BioMed Research International: Tissue Engineering The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. An ECM-Mimicking, Mesenchymal Stem Cell-Embedded Hybrid Scaffold for Bone Regeneration Wed, 15 Nov 2017 00:00:00 +0000 While biologically feasible, bone repair is often inadequate, particularly in cases of large defects. The search for effective bone regeneration strategies has led to the emergence of bone tissue engineering (TE) techniques. When integrating electrospinning techniques, scaffolds featuring randomly oriented or aligned fibers, characteristic of the extracellular matrix (ECM), can be fabricated. In parallel, mesenchymal stem cells (MSCs), which are capable of both self-renewing and differentiating into numerous tissue types, have been suggested to be a suitable option for cell-based tissue engineering therapies. This work aimed to create a novel biocompatible hybrid scaffold composed of electrospun polymeric nanofibers combined with osteoconductive ceramics, loaded with human MSCs, to yield a tissue-like construct to promote in vivo bone formation. Characterization of the cell-embedded scaffolds demonstrated their resemblance to bone tissue extracellular matrix, on both micro- and nanoscales and MSC viability and integration within the electrospun nanofibers. Subcutaneous implantation of the cell-embedded scaffolds in the dorsal side of mice led to new bone, muscle, adipose, and connective tissue formation within 8 weeks. This hybrid scaffold may represent a step forward in the pursuit of advanced bone tissue engineering scaffolds. Jozafina Haj, Tharwat Haj Khalil, Mizied Falah, Eyal Zussman, and Samer Srouji Copyright © 2017 Jozafina Haj et al. All rights reserved. Effects of Electrostatic Field on Osteoblast Cells for Bone Regeneration Applications Mon, 13 Nov 2017 00:00:00 +0000 Many external stimulations have been shown to promote bone regeneration. The effects of an alternating current (AC) electrostatic field, one of external stimulations, generated from a device with high voltage and low current output on human osteoblastic cell line have been investigated in this study. We investigated how human osteoblasts responded to an AC electrostatic field, and the output parameters were set as 1 kV and 160 μA. Our results showed that, under such condition, the AC electrostatic field had a downregulation effect on the production ability of alkaline phosphatase and type 1 collagen expression. However, the expression of osteocalcin gene was elevated on the end of EFID treatment suggesting that AC electrostatic field might be a potential stimulation for accelerating the differentiation of osteoblastic cells. Chen-Ying Su, Tzan Fang, and Hsu-Wei Fang Copyright © 2017 Chen-Ying Su et al. All rights reserved. Multilevel Thresholding Method Based on Electromagnetism for Accurate Brain MRI Segmentation to Detect White Matter, Gray Matter, and CSF Thu, 09 Nov 2017 00:00:00 +0000 This work explains an advanced and accurate brain MRI segmentation method. MR brain image segmentation is to know the anatomical structure, to identify the abnormalities, and to detect various tissues which help in treatment planning prior to radiation therapy. This proposed technique is a Multilevel Thresholding (MT) method based on the phenomenon of Electromagnetism and it segments the image into three tissues such as White Matter (WM), Gray Matter (GM), and CSF. The approach incorporates skull stripping and filtering using anisotropic diffusion filter in the preprocessing stage. This thresholding method uses the force of attraction-repulsion between the charged particles to increase the population. It is the combination of Electromagnetism-Like optimization algorithm with the Otsu and Kapur objective functions. The results obtained by using the proposed method are compared with the ground-truth images and have given best values for the measures sensitivity, specificity, and segmentation accuracy. The results using 10 MR brain images proved that the proposed method has accurately segmented the three brain tissues compared to the existing segmentation methods such as K-means, fuzzy C-means, OTSU MT, Particle Swarm Optimization (PSO), Bacterial Foraging Algorithm (BFA), Genetic Algorithm (GA), and Fuzzy Local Gaussian Mixture Model (FLGMM). G. Sandhya, Giri Babu Kande, and T. Satya Savithri Copyright © 2017 G. Sandhya et al. All rights reserved. Rapid Analyses of Polyetheretherketone Wear Characteristics by Accelerated Wear Testing with Microfabricated Surfaces for Artificial Joint Systems Thu, 02 Nov 2017 06:10:30 +0000 Wear particle-induced biological responses are the major factors resulting in the loosening and then failure of total joint arthroplasties. It is feasible to improve the lubrication and reduce the wear of artificial joint system. Polyetheretherketone (PEEK) is considered as a potential bearing material due to its mechanical characteristics of resistance to fatigue strain. The PEEK wear particles have been indicated to be involved in biological responses in vitro, and further studies regarding the wear phenomena and wear particle generation are needed. In this study, we have established an accelerated wear testing system with microfabricated surfaces. Various contact pressures and lubricants have been utilized in the accelerated wear tests. Our results showed that increasing contact pressure resulted in an increase of wear particle sizes and wear rate, and the size of PEEK wear particles can be controlled by the feature size of microfabricated surfaces. These results provided the information rapidly about factors that affect the morphology and amount of PEEK wear particles and can be applied in the future for application of PEEK on the biological articulation system. Chen-Ying Su, Chien-Wei Kuo, and Hsu-Wei Fang Copyright © 2017 Chen-Ying Su et al. All rights reserved. Evaluation of Immunosuppressive Therapy Use for Tracheal Transplantation with Trachea-Mimetic Bellows Scaffolds in a Rabbit Model Thu, 26 Oct 2017 06:53:20 +0000 The objective of this study was to evaluate the use of immunosuppressive therapy with high-dose cyclosporine, high-dose azathioprine, and a combination of low-dose cyclosporine and azathioprine after tracheal reconstruction by using a trachea-mimetic graft of polycaprolactone (PCL) bellows-type scaffold in a rabbit model. Twenty-four healthy New Zealand white rabbits were used in the study. All underwent circumferential tracheal replacement using tissue-engineered tracheal graft, prepared from PCL bellows scaffold reinforced with silicone ring, collagen hydrogel, and human turbinate mesenchymal stromal cell (hTMSC) sheets. The control group (Group 1) received no medication. The three experimental groups were given daily cyclosporine intramuscular doses of 10 mg/kg (Group 2), azathioprine oral doses of 5 mg/kg (Group 3), and azathioprine oral doses of 2.5 mg/kg plus cyclosporine intramuscular doses of 5 mg/kg (Group 4) for 4 weeks or until death. Group 1 had longer survival times compared to Group 2 or Group 3. Each group except for Group 1 experienced decreases in amount of nutrition and weight loss. In addition, compared with the other groups, Group 2 had significantly increased serum interleukin-2 and interferon- levels 7 days after transplantation. The results of this study showed that the administration of cyclosporine and/or azathioprine after tracheal transplantation had no beneficial effects. Furthermore, the administration of cyclosporine had side effects, including extreme weight loss, respiratory distress, and diarrhea. Therefore, cyclosporine and azathioprine avoidance may be recommended for tracheal reconstruction using a native trachea-mimetic graft of PCL bellows-type scaffold in a rabbit model. Jae Yeon Lee, Jeong Hun Park, Soo Jin Son, Mina Han, Gonhyung Kim, Seong Soo Kang, Seok Hwa Choi, and Dong-Woo Cho Copyright © 2017 Jae Yeon Lee et al. All rights reserved. Dental Implant Surrounding Marginal Bone Level Evaluation: Platform Switching versus Platform Matching—One-Year Retrospective Study Tue, 24 Oct 2017 00:00:00 +0000 The benefits and feasibility of platform switching have been discussed in several studies, reporting lesser crestal bone loss in platform-switched implants than in platform-matched implants. Objective. The aim of the present study was to observe the changes in vertical and horizontal marginal bone levels in platform-switched and platform-matched dental implants. Materials and Methods. 51 patients received 60 dental implants in the present study over a 1-year period. Measurement was performed between the implant shoulder and the most apical and horizontal marginal defect by periapical radiographs to examine the changes of peri-implant alveolar bone before and 12 months after prosthodontic restoration delivery. Results. These marginal bone measurements showed a bone gain of  mm in the vertical gap and  mm in the horizontal gap of platform matching, while in platform switching a bone gain of  mm () in the vertical gap and  mm in the horizontal gap was found. The average vertical gap reduction from the baseline until 12 months was  mm in platform switching and  mm in platform matching (). Conclusions. Within the limitations of the present study, platform switching seemed to be more effective for a better peri-implant alveolar bone vertical and horizontal gap reduction at 1 year. Eisner Salamanca, Jerry C.-Y. Lin, Chi-Yang Tsai, Yung-Szu Hsu, Haw-Ming Huang, Nai-Chia Teng, Peter D. Wang, Sheng-Wei Feng, May-Show Chen, and Wei-Jen Chang Copyright © 2017 Eisner Salamanca et al. All rights reserved. Effects of rhBMP-2 Loaded Titanium Reinforced Collagen Membranes on Horizontal Bone Augmentation in Dogs Tue, 17 Oct 2017 09:52:11 +0000 The aim of this study was to evaluate the efficacy of growth factor loaded collagen membranes on new bone formation during horizontal bone augmentation. Mandibular defects (4 × 4 × 4 mm) were surgically prepared in six male beagle dogs, which were then protected with one of three types of membranes: (1) titanium mesh, (2) titanium reinforced collagen, or (3) rhBMP-2 loaded titanium reinforced collagen. Animals were euthanized 8 and 16 weeks after surgery, and nondecalcified specimens were prepared and histomorphologically investigated to determine the degree of osteogenesis. Data were analyzed with Friedman test. With respect to the degree of osteogenesis at earlier stage (8 weeks after surgery), there was significantly higher new bone ratio in rhBMP-2 loaded membrane group (). However, with respect to the long-term results (16 weeks after surgery), there were no significant differences among the three membranes (). Based on histomorphometric analysis, there were no significant differences in horizontal bone gaining ratio (). Ki-Sun Lee, Yu-Sung Jeon, Sang-Wan Shin, and Jeong-Yol Lee Copyright © 2017 Ki-Sun Lee et al. All rights reserved. Tapered, Double-Lead Threads Single Implants Placed in Fresh Extraction Sockets and Healed Sites of the Posterior Jaws: A Multicenter Randomized Controlled Trial with 1 to 3 Years of Follow-Up Wed, 13 Sep 2017 00:00:00 +0000 Purpose. To evaluate the survival, success, and complication rates of tapered double-lead threads single implants, placed in fresh extraction sockets and healed sites of the posterior jaws. Methods. The enrolled patients were randomly divided into 2 groups: in the test group (TG), all implants were inserted at the time of tooth extraction; in the control group (CG), all implants were placed 3 months after extraction. The implants were followed for a period of 1 to 3 years after loading. The main outcomes were implant survival, complications, and implant-crown success. Results. Ninety-two patients had 97 installed implants (49 in the TG, 48 in the CG). Only two implants failed, in the TG; the survival rates were therefore 95.9% (47/49) and 100% (48/48) for TG and CG, respectively. In the surviving implants, no complications were reported, for an implant-crown success of 100%. Conclusions. Although a significant difference was found in the levels of primary stability between TG and CG, single implants placed in fresh extraction sockets and healed sites of the posterior jaws had similar survival and complication rates. Crestal bone levels and peri-implant bone resorption showed similar values. A longer follow-up period is however required, to confirm these positive outcomes. Alessandro Cucchi, Elisabetta Vignudelli, Simonetta Franco, Luca Levrini, Dario Castellani, Luca Pagliani, Massimiliano Rea, Claudio Modena, Giulio Sandri, and Carlo Longhi Copyright © 2017 Alessandro Cucchi et al. All rights reserved. Expression of C4.4A in an In Vitro Human Tissue-Engineered Skin Model Thu, 07 Sep 2017 00:00:00 +0000 A multi-LU-domain-containing protein denoted C4.4A exhibits a tightly regulated membrane-associated expression in the suprabasal layers of stratified squamous epithelia such as skin and the esophagus, and the expression of C4.4A is dysregulated in various pathological conditions. However, the biological function of C4.4A remains unknown. To enable further studies, we evaluated the expression of C4.4A in monolayer cultures of normal human keratinocytes and in tissue-engineered skin substitutes (TESs) produced by the self-assembly approach, which allow the formation of a fully differentiated epidermis tissue. Results showed that, in monolayer, C4.4A was highly expressed in the centre of keratinocyte colonies at cell-cell contacts areas, while some cells located at the periphery presented little C4.4A expression. In TES, emergence of C4.4A expression coincided with the formation of the stratum spinosum. After the creation of a wound within the TES, C4.4A expression was observed in the suprabasal keratinocytes of the migrating epithelium, with the exception of the foremost leading keratinocytes, which were negative for C4.4A. Our results are consistent with previous data in mouse embryogenesis and wound healing. Based on these findings, we conclude that this human TES model provides an excellent surrogate for studies of C4.4A and Haldisin expressions in human stratified epithelia. Benedikte Jacobsen, Danielle Larouche, Olivier Rochette-Drouin, Michael Ploug, and Lucie Germain Copyright © 2017 Benedikte Jacobsen et al. All rights reserved. Growth Factor-Reinforced ECM Fabricated from Chemically Hypoxic MSC Sheet with Improved In Vivo Wound Repair Activity Tue, 05 Sep 2017 00:00:00 +0000 MSC treatment can promote cutaneous wound repair through multiple mechanisms, and paracrine mediators secreted by MSC are responsible for most of its therapeutic benefits. Recently, MSC sheet composed of live MSCs and their secreted ECMs was reported to promote wound healing; however, whether its ECM alone could accelerate wound closure remained unknown. In this study, Nc-ECM and Cc-ECM were prepared from nonconditioned and CoCl2-conditioned MSC sheets, respectively, and their wound healing properties were evaluated in a mouse model of full-thickness skin defect. Our results showed that Nc-ECM can significantly promote wound repair through early adipocyte recruitment, rapid reepithelialization, enhanced granulation tissue growth, and augmented angiogenesis. Moreover, conditioning of MSC sheet with CoCl2 dramatically enriched its ECM with collagen I, collagen III, TGF-β1, VEGF, and bFGF via activation of HIF-1α and hence remarkably improved its ECM’s in vivo wound healing potency. All the Cc-ECM-treated wounds completely healed on day 7, while Nc-ECM-treated wounds healed about , and no-treatment wounds only healed (). Therefore, we believe that such growth factor-reinforced ECM fabricated from chemically hypoxic MSC sheet has the potential for clinical translation and will lead to a MSC-derived, cost-effective, bankable biomaterial for wound management. Hui-Cong Du, Lin Jiang, Wen-Xin Geng, Jing Li, Rui Zhang, Jin-Ge Dang, Mao-Guo Shu, and Li-Wen Li Copyright © 2017 Hui-Cong Du et al. All rights reserved. Vascular Tissue Engineering: Effects of Integrating Collagen into a PCL Based Nanofiber Material Mon, 28 Aug 2017 00:00:00 +0000 The engineering of vascular grafts is a growing field in regenerative medicine. Although numerous attempts have been made, the current vascular grafts made of polyurethane (PU), Dacron®, or Teflon® still display unsatisfying results. Electrospinning of biopolymers and native proteins has been in the focus of research to imitate the extracellular matrix (ECM) of vessels to produce a small caliber, off-the-shelf tissue engineered vascular graft (TEVG) as a substitute for poorly performing PU, Dacron, or Teflon prostheses. Blended poly-ε-caprolactone (PCL)/collagen grafts have shown promising results regarding biomechanical and cell supporting features. In order to find a suitable PCL/collagen blend, we fabricated plane electrospun PCL scaffolds using various collagen type I concentrations ranging from 5% to 75%. We analyzed biocompatibility and morphological aspects in vitro. Our results show beneficial features of collagen I integration regarding cell viability and functionality, but also adverse effects like the loss of a confluent monolayer at high concentrations of collagen. Furthermore, electrospun PCL scaffolds containing 25% collagen I seem to be ideal for engineering vascular grafts. Ulf Bertram, Dominik Steiner, Benjamin Poppitz, Dirk Dippold, Katrin Köhn, Justus P. Beier, Rainer Detsch, Aldo R. Boccaccini, Dirk W. Schubert, Raymund E. Horch, and Andreas Arkudas Copyright © 2017 Ulf Bertram et al. All rights reserved. Histological Evidence of the Osseointegration of Fractured Direct Metal Laser Sintering Implants Retrieved after 5 Years of Function Sun, 27 Aug 2017 00:00:00 +0000 Background. Direct metal laser sintering (DMLS) is an additive manufacturing technique that allows the fabrication of dental implants layer by layer through the laser fusion of titanium microparticles. The surface of DMLS implants is characterized by a high open porosity with interconnected pores of different sizes; therefore, it has the potential to enhance and accelerate bone healing. To date, however, there are no histologic/histomorphometric studies in the literature evaluating the interface between bone and DMLS implants in the long-term. Purpose. To evaluate the interface between bone and DMLS implants retrieved after 5 years of functional loading. Methods. Two fractured DMLS implants were retrieved from the human jaws, using a 5 mm trephine bur. Both the implants were clinically stable and functioned regularly before fracture. The specimens were processed for histologic/histomorphometric evaluation; the bone-to-implant contact (BIC%) was calculated. Results. Compact, mature lamellar bone was found over most of the DMLS implants in close contact with the implant surface; the histomorphometric evaluation showed a mean BIC% of 66.1% (±4.5%). Conclusions. The present histologic/histomorphometric study showed that DMLS implants were well integrated in bone, after 5 years of loading, with the peri-implant bone undergoing continuous remodeling at the interface. Francesco Mangano, Carlo Mangano, Adriano Piattelli, and Giovanna Iezzi Copyright © 2017 Francesco Mangano et al. All rights reserved. Towards a Biohybrid Lung: Endothelial Cells Promote Oxygen Transfer through Gas Permeable Membranes Wed, 23 Aug 2017 06:51:56 +0000 In patients with respiratory failure, extracorporeal lung support can ensure the vital gas exchange via gas permeable membranes but its application is restricted by limited long-term stability and hemocompatibility of the gas permeable membranes, which are in contact with the blood. Endothelial cells lining these membranes promise physiological hemocompatibility and should enable prolonged application. However, the endothelial cells increase the diffusion barrier of the blood-gas interface and thus affect gas transfer. In this study, we evaluated how the endothelial cells affect the gas exchange to optimize performance while maintaining an integral cell layer. Human umbilical vein endothelial cells were seeded on gas permeable cell culture membranes and cultivated in a custom-made bioreactor. Oxygen transfer rates of blank and endothelialized membranes in endothelial culture medium were determined. Cell morphology was assessed by microscopy and immunohistochemistry. Both setups provided oxygenation of the test fluid featuring small standard deviations of the measurements. Throughout the measuring range, the endothelial cells seem to promote gas transfer to a certain extent exceeding the blank membranes gas transfer performance by up to 120%. Although the underlying principles hereof still need to be clarified, the results represent a significant step towards the development of a biohybrid lung. Sarah Menzel, Nicole Finocchiaro, Christine Donay, Anja Lena Thiebes, Felix Hesselmann, Jutta Arens, Suzana Djeljadini, Matthias Wessling, Thomas Schmitz-Rode, Stefan Jockenhoevel, and Christian Gabriel Cornelissen Copyright © 2017 Sarah Menzel et al. All rights reserved. Bioengineering Materials in Dental Application Mon, 21 Aug 2017 08:37:03 +0000 Wei-Jen Chang, Abe Shinichi, Shinji Kamakura, Ren-Yeong Huang, and Jung-Wei Chen Copyright © 2017 Wei-Jen Chang et al. All rights reserved. Histologic and Histomorphometric Comparison between Sintered Nanohydroxyapatite and Anorganic Bovine Xenograft in Maxillary Sinus Grafting: A Split-Mouth Randomized Controlled Clinical Trial Sun, 06 Aug 2017 00:00:00 +0000 The presence of vital bone after maxillary sinus augmentation is crucial to enhance the quality of bone-implant interface, ensuring predictable long-term results. The aims of this RCT with split-mouth design were the histologic and histomorphometric comparison of two different biomaterials in sinus elevation after 6 months of healing and the evaluation of the clinical outcomes of implants inserted in the augmented areas after 12 months of prosthetic loading. Twenty-eight patients (10 females, 18 males) were treated with bilateral sinus floor elevation with lateral approach. Pure sintered nanohydroxyapatite (NHA) and anorganic bovine bone (ABB) were used as test and active control, respectively. After six months, 52 bone biopsies were harvested from 26 patients, and 107 implants were inserted in the augmented areas. Histomorphometry showed that, in the two groups, vital bone percentages were % (NHA) and % (ABB) (), marrow spaces percentages were % (NHA) and % (ABB) (), and residual graft percentages were % (NHA) and % (ABB) (). After 6 months of healing, no statistically significant difference was present in histomorphometric outcomes between NHA and ABB groups. Implant survival rate in NHA group after 12 months of loading was 96.4%, showing no statistically significant differences with ABB group. Claudio Stacchi, Teresa Lombardi, Francesco Oreglia, Andrea Alberghini Maltoni, and Tonino Traini Copyright © 2017 Claudio Stacchi et al. All rights reserved. Adipose Extracellular Matrix/Stromal Vascular Fraction Gel Secretes Angiogenic Factors and Enhances Skin Wound Healing in a Murine Model Tue, 01 Aug 2017 08:58:01 +0000 Mesenchymal stem cells are an attractive cell type for cytotherapy in wound healing. The authors recently developed a novel, adipose-tissue-derived, injectable extracellular matrix/stromal vascular fraction gel (ECM/SVF-gel) for stem cell therapy. This study was designed to assess the therapeutic effects of ECM/SVF-gel on wound healing and potential mechanisms. ECM/SVF-gel was prepared for use in nude mouse excisional wound healing model. An SVF cell suspension and phosphate-buffered saline injection served as the control. The expression levels of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and monocyte chemotactic protein-1 (MCP-1) in ECM/SVF-gel were analyzed at different time points. Angiogenesis (tube formation) assays of ECM/SVF-gel extracts were evaluated, and vessels density in skin was determined. The ECM/SVF-gel extract promoted tube formation in vitro and increased the expression of the angiogenic factors VEGF and bFGF compared with those in the control. The expression of the inflammatory chemoattractant MCP-1 was high in ECM/SVF-gel at the early stage and decreased sharply during the late stage of wound healing. The potent angiogenic effects exerted by ECM/SVF-gel may contribute to the improvement of wound healing, and these effects could be related to the enhanced inflammatory response in ECM/SVF-gel during the early stage of wound healing. Mingliang Sun, Yunfan He, Tao Zhou, Pan Zhang, Jianhua Gao, and Feng Lu Copyright © 2017 Mingliang Sun et al. All rights reserved. In Vitro Laser Treatment Platform Construction with Dental Implant Thread Surface on Bacterial Adhesion for Peri-Implantitis Sun, 16 Jul 2017 00:00:00 +0000 This study constructs a standard in vitro laser treatment platform with dental implant thread surface on bacterial adhesion for peri-implantitis at different tooth positions. The standard clinical adult tooth jaw model was scanned to construct the digital model with 6 mm bone loss depth on behalf of serious peri-implantitis at the incisor, first premolar, and first molar. A cylindrical suite connected to the implant and each tooth root in the jaw model was designed as one experimental unit set to allow the suite to be replaced for individual bacterial adhesion. The digital peri-implantitis and suite models were exported to fulfill the physical model using ABS material in a 3D printer. A 3 mm diameter specimen implant on bacterial adhesion against Escherichia coli was performed for gram-negative bacteria. An Er:YAG laser, working with a chisel type glass tip, was moved from the buccal across the implant thread to the lingual for about 30 seconds per sample to verify the in vitro laser treatment platform. The result showed that the sterilization rate can reach 99.3% and the jaw model was not damaged after laser irradiation testing. This study concluded that using integrated image processing, reverse engineering, CAD system, and a 3D printer to construct a peri-implantitis model replacing the implant on bacterial adhesion and acceptable sterilization rate proved the feasibility of the proposed laser treatment platform. Hsien-Nan Kuo, Hsiang-I Mei, Tung-Kuan Liu, Tse-Ying Liu, Lun-Jou Lo, and Chun-Li Lin Copyright © 2017 Hsien-Nan Kuo et al. All rights reserved. Retracted: Exogenous IL-4-Expressing Bone Marrow Mesenchymal Stem Cells for the Treatment of Autoimmune Sensorineural Hearing Loss in a Guinea Pig Model Thu, 13 Jul 2017 00:00:00 +0000 BioMed Research International Copyright © 2017 BioMed Research International. All rights reserved. Retracted: Experimental Study of Local Inner Ear Gene Therapy for Controlling Autoimmune Sensorineural Hearing Loss Thu, 13 Jul 2017 00:00:00 +0000 BioMed Research International Copyright © 2017 BioMed Research International. All rights reserved. Breast Carcinoma: From Initial Tumor Cell Detachment to Settlement at Secondary Sites Wed, 12 Jul 2017 07:10:17 +0000 Metastasis represents a multistep cascade of cancer cell alterations accompanied by structural and functional changes within the tumor microenvironment which may involve the induction of a retrodifferentiation program. Major steps in metastatic developments include (A) cell detachment from the primary tumor site involving epithelial-mesenchymal transition (EMT), (B) migration and invasion into surrounding tissue, (C) transendothelial intravasation into the vasculature of blood and/or lymphatic vessels as circulating tumor cells (CTCs), (D) dissemination to distant organs, and (E) extravasation of CTCs to secondary sites as disseminated tumor cells (DTCs). This article highlights some aspects of the metastatic cascade with a focus on breast cancer cells. Metastatic steps critically depend on the capability of cancer cells to adapt to distant tissues and the corresponding new microenvironment. As a consequence, increasing plasticity and developmental changes paralleled by acquisition of new cancer cell functionalities challenge a successful therapeutic approach. Catharina Melzer, Juliane von der Ohe, and Ralf Hass Copyright © 2017 Catharina Melzer et al. All rights reserved. Natural Scaffolds for Regenerative Medicine: Direct Determination of Detergents Entrapped in Decellularized Heart Valves Tue, 06 Jun 2017 00:00:00 +0000 The increasing urgency for replacement of pathological heart valves is a major stimulus for research on alternatives to glutaraldehyde-treated grafts. New xenogeneic acellular heart valve substitutes that can be repopulated by host cells are currently under investigation. Anionic surfactants, including bile acids, have been widely used to eliminate the resident cell components chiefly responsible for the immunogenicity of the tissue, even if detergent toxicity might present limitations to the survival and/or functional expression of the repopulating cells. To date, the determination of residual detergent has been carried out almost exclusively on the washings following cell removal procedures. Here, a novel HPLC-based procedure is proposed for the direct quantification of detergent (cholate, deoxycholate, and taurodeoxycholate) residues entrapped in the scaffold of decellularized porcine aortic and pulmonary valves. The method was demonstrated to be sensitive, reproducible, and extendable to different types of detergent. This assessment also revealed that cell-depleted heart valve scaffolds prepared according to procedures currently considered for clinical use might contain significant amount of surfactant. Monica Dettin, Annj Zamuner, Filippo Naso, Antonella Monteleone, Michele Spina, and Gino Gerosa Copyright © 2017 Monica Dettin et al. All rights reserved. Influence of Deformation and Stress between Bone and Implant from Various Bite Forces by Numerical Simulation Analysis Sun, 28 May 2017 09:43:08 +0000 Endosseous oral implant is applied for orthodontic anchorage in subjects with multiple tooth agenesis. Its effectiveness under orthodontic loading has been demonstrated clinically and experimentally. This study investigates the deformation and stress on the bone and implant for different bite forces by three-dimensional (3D) finite element (FE) methods. A numerical simulation of deformation and stress distributions around implants was used to estimate the survival life for implants. The model was applied to determine the pattern and distribution of deformations and stresses within the endosseous implant and on supporting tissues when the endosseous implant is used for orthodontic anchorage. A threaded implant was placed in an edentulous segment of a human mandible with cortical and cancellous bone. Analytical results demonstrate that maximum stresses were always located around the implant neck in marginal bone. The results also reveal that the stress for oblique force has the maximum value followed by the horizontal force; the vertical force causes the stress to have the minimum value between implant and bone. Thus, this area should be preserved clinically to maintain the structure and function of a bone implant. Hsin-Chung Cheng, Boe-Yu Peng, May-Show Chen, Chiung-Fang Huang, Yi Lin, and Yung-Kang Shen Copyright © 2017 Hsin-Chung Cheng et al. All rights reserved. Implant Stability in the Posterior Maxilla: A Controlled Clinical Trial Thu, 25 May 2017 06:28:40 +0000 Aim. To evaluate the primary and secondary stability of implants in the posterior maxilla. Methods. Patients were allocated into three groups: (A) native bone, (B) partially regenerated bone, and (C) nearly totally regenerated bone. Insertion torque (IT) and implant stability quotient (ISQ) were measured at placement, to evaluate whether satisfactory high primary stability (IT ≥ 45 N/cm; ISQ ≥ 60) was achieved; ISQ was measured 15, 30, 45, and 60 days after placement, to investigate the evolution to secondary stability. Results. 133 implants (Anyridge®, Megagen) were installed in 59 patients: 55 fixtures were placed in Group A, 57 in Group B, and 21 in Group C. Fifty-two implants had satisfactory high primary stability (IT ≥ 45 N/cm; ISQ ≥ 60). A positive correlation was found between all variables (IT, ISQ at t = 0, t = 60), and statistically higher IT and ISQ values were found for implants with satisfactory high primary stability. Significant differences were found for IT and ISQ between the groups (A, B, and C); however, no drops were reported in the median ISQ values during the healing period. Conclusions. The evaluation of the primary and secondary implant stability may contribute to higher implant survival/success rates in critical areas, such as the regenerated posterior maxilla. The present study is registered in the ISRCTN registry with ID ISRCTN33469250. Raquel Zita Gomes, Mario Ramalho de Vasconcelos, Isabel Maria Lopes Guerra, Rute Alexandra Borges de Almeida, and Antonio Cabral de Campos Felino Copyright © 2017 Raquel Zita Gomes et al. All rights reserved. From Human Mesenchymal Stem Cells to Insulin-Producing Cells: Comparison between Bone Marrow- and Adipose Tissue-Derived Cells Thu, 11 May 2017 00:00:00 +0000 The aim of this study is to compare human bone marrow-derived mesenchymal stem cells (BM-MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs), for their differentiation potentials to form insulin-producing cells. BM-MSCs were obtained during elective orthotopic surgery and AT-MSCs from fatty aspirates during elective cosmetics procedures. Following their expansion, cells were characterized by phenotyping, trilineage differentiation ability, and basal gene expression of pluripotency genes and for their metabolic characteristics. Cells were differentiated according to a Trichostatin-A based protocol. The differentiated cells were evaluated by immunocytochemistry staining for insulin and c-peptide. In addition the expression of relevant pancreatic endocrine genes was determined. The release of insulin and c-peptide in response to a glucose challenge was also quantitated. There were some differences in basal gene expression and metabolic characteristics. After differentiation the proportion of the resulting insulin-producing cells (IPCs), was comparable among both cell sources. Again, there were no differences neither in the levels of gene expression nor in the amounts of insulin and c-peptide release as a function of glucose challenge. The properties, availability, and abundance of AT-MSCs render them well-suited for applications in regenerative medicine. Conclusion. BM-MSCs and AT-MSCs are comparable regarding their differential potential to form IPCs. The availability and properties of AT-MSCs render them well-suited for applications in regenerative medicine. Mahmoud M. Gabr, Mahmoud M. Zakaria, Ayman F. Refaie, Engy A. Abdel-Rahman, Asmaa M. Reda, Sameh S. Ali, Sherry M. Khater, Sylvia A. Ashamallah, Amani M. Ismail, Hossam El-Din A. Ismail, Nagwa El-Badri, and Mohamed A. Ghoneim Copyright © 2017 Mahmoud M. Gabr et al. All rights reserved. Bone Tissue Engineering: Scaffolds with Osteoinductivity for Bone Regeneration Tue, 02 May 2017 00:00:00 +0000 Shen Liu, Changmin Hu, and Zheng Ren Copyright © 2017 Shen Liu et al. All rights reserved. Surface Treatment on Physical Properties and Biocompatibility of Orthodontic Power Chains Sun, 30 Apr 2017 00:00:00 +0000 The conventional orthodontic power chain, often composed of polymer materials, has drawbacks such as a reduction of elasticity owing to water absorption as well as surface discoloration and staining resulting from food or beverages consumed by the patient. The goal of this study was to develop a surface treatment (nanoimprinting) for orthodontic power chains and to alleviate their shortcomings. A concave template (anodic alumina) was manufactured by anodization process using pure aluminum substrate by employing the nanoimprinting process. Convex nanopillars were fabricated on the surface of orthodontic power chains, resulting in surface treatment. Distinct parameters of the nanoimprinting process (e.g., imprinting temperature, imprinting pressure, imprinting time, and demolding temperature) were used to fabricate nanopillars on the surface of orthodontic power chains. The results of this study showed that the contact angle of the power chains became larger after surface treatment. In addition, the power chains changed from hydrophilic to hydrophobic. The power chain before surface treatment without water absorption had a water absorption rate of approximately 4%, whereas a modified chain had a water absorption rate of approximately 2%–4%. Furthermore, the color adhesion of the orthodontic power chains after surface modification was less than that before surface modification. H. C. Cheng, M. S. Chen, B. Y. Peng, W. T. Lin, Y. K. Shen, and Y. H. Wang Copyright © 2017 H. C. Cheng et al. All rights reserved. Decellularization Strategies for Regenerative Medicine: From Processing Techniques to Applications Sun, 30 Apr 2017 00:00:00 +0000 As the gap between donors and patients in need of an organ transplant continues to widen, research in regenerative medicine seeks to provide alternative strategies for treatment. One of the most promising techniques for tissue and organ regeneration is decellularization, in which the extracellular matrix (ECM) is isolated from its native cells and genetic material in order to produce a natural scaffold. The ECM, which ideally retains its inherent structural, biochemical, and biomechanical cues, can then be recellularized to produce a functional tissue or organ. While decellularization can be accomplished using chemical and enzymatic, physical, or combinative methods, each strategy has both benefits and drawbacks. The focus of this review is to compare the advantages and disadvantages of these methods in terms of their ability to retain desired ECM characteristics for particular tissues and organs. Additionally, a few applications of constructs engineered using decellularized cell sheets, tissues, and whole organs are discussed. Anna Gilpin and Yong Yang Copyright © 2017 Anna Gilpin and Yong Yang. All rights reserved. Fabrication and Evaluation of Electrospun, 3D-Bioplotted, and Combination of Electrospun/3D-Bioplotted Scaffolds for Tissue Engineering Applications Thu, 27 Apr 2017 07:50:41 +0000 Electrospun scaffolds provide a dense framework of nanofibers with pore sizes and fiber diameters that closely resemble the architecture of native extracellular matrix. However, it generates limited three-dimensional structures of relevant physiological thicknesses. 3D printing allows digitally controlled fabrication of three-dimensional single/multimaterial constructs with precisely ordered fiber and pore architecture in a single build. However, this approach generally lacks the ability to achieve submicron resolution features to mimic native tissue. The goal of this study was to fabricate and evaluate 3D printed, electrospun, and combination of 3D printed/electrospun scaffolds to mimic the native architecture of heterogeneous tissue. We assessed their ability to support viability and proliferation of human adipose derived stem cells (hASC). Cells had increased proliferation and high viability over 21 days on all scaffolds. We further tested implantation of stacked-electrospun scaffold versus combined electrospun/3D scaffold on a cadaveric pig knee model and found that stacked-electrospun scaffold easily delaminated during implantation while the combined scaffold was easier to implant. Our approach combining these two commonly used scaffold fabrication technologies allows for the creation of a scaffold with more close resemblance to heterogeneous tissue architecture, holding great potential for tissue engineering and regenerative medicine applications of osteochondral tissue and other heterogeneous tissues. Liliana F. Mellor, Pedro Huebner, Shaobo Cai, Mahsa Mohiti-Asli, Michael A. Taylor, Jeffrey Spang, Rohan A. Shirwaiker, and Elizabeth G. Loboa Copyright © 2017 Liliana F. Mellor et al. All rights reserved. Culture of iPSCs Derived Pancreatic β-Like Cells In Vitro Using Decellularized Pancreatic Scaffolds: A Preliminary Trial Wed, 05 Apr 2017 06:43:23 +0000 Diabetes mellitus is a disease which has affected 415 million patients in 2015. In an effort to replace the significant demands on transplantation and morbidity associated with transplantation, the production of β-like cells differentiated from induced pluripotent stem cells (iPSCs) was evaluated. This approach is associated with promising decellularized scaffolds with natural extracellular matrix (ECM) and ideal cubic environment that will promote cell growth in vivo. Our efforts focused on combining decellularized rat pancreatic scaffolds with mouse GFP+-iPSCs-derived pancreatic β-like cells, to evaluate whether decellularized scaffolds could facilitate the growth and function of β-like cells. β-like cells were differentiated from GFP+-iPSCs and evaluated via cultivating in the dynamic circulation perfusion device. Our results demonstrated that decellularized pancreatic scaffolds display favorable biochemical properties. Furthermore, not only could the scaffolds support the survival of β-like cells, but they also accelerated the expression of the insulin as compared to plate-based cell culture. In conclusion, these results suggest that decellularized pancreatic scaffolds could provide a suitable platform for cellular activities of β-like cells including survival and insulin secretion. This study provides preliminary support for regenerating insulin-secreting organs from the decellularized scaffolds combined with iPSCs derived β-like cells as a potential clinical application. Jian Wan, Yan Huang, Pengcheng Zhou, Yibing Guo, Cen Wu, Shajun Zhu, Yao Wang, Lei Wang, Yuhua Lu, and Zhiwei Wang Copyright © 2017 Jian Wan et al. All rights reserved. Management of Hepple Stage V Osteochondral Lesion of the Talus with a Platelet-Rich Plasma Scaffold Thu, 16 Mar 2017 10:01:37 +0000 There has been no consensus on the treatment or prognosis of Hepple stage V osteochondral lesions of the talus (OLTs), especially for lesions greater than 1.5 cm2 in size. The objective of this study was to investigate the clinical outcomes achieved upon application of a platelet-rich plasma (PRP) scaffold with a cancellous bone autograft for Hepple stage V OLTs. Fourteen patients (mean age, 39 years) were treated with a cancellous bone graft and a PRP scaffold between 2013 and 2015. The mean time to surgical treatment was 23.5 months. Ankle X-ray and magnetic resonance imaging were performed at the final follow-up. Functional outcomes were evaluated according to the Visual Analog Scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) score, and Short Form 36 (SF-36) score. The range of motion (ROM) of the ankle joint and complications also were recorded. Thirteen patients completed the full follow-up, with a mean follow-up duration of 18 months. MRI demonstrated the complete regeneration of subchondral bone and cartilage in all patients. The postoperative VAS, AOFAS ankle and hindfoot, and SF-36 scores were improved significantly (all ) without obvious complications. We suggest that, for the Hepple stage V OLTs, management with cancellous bone graft and PRP scaffold may be a safe and effective treatment. Wenqi Gu, Tanzhu Li, Zhongmin Shi, Guohua Mei, Jianfeng Xue, Jian Zou, Xiaokang Wang, Haotong Zhang, and Hongwei Xu Copyright © 2017 Wenqi Gu et al. All rights reserved. Collagen Sponge Functionalized with Chimeric Anti-BMP-2 Monoclonal Antibody Mediates Repair of Critical-Size Mandibular Continuity Defects in a Nonhuman Primate Model Thu, 16 Mar 2017 00:00:00 +0000 Antibody-mediated osseous regeneration (AMOR) has been introduced by our research group as a tissue engineering approach to capture of endogenous growth factors through the application of specific monoclonal antibodies (mAbs) immobilized on a scaffold. Specifically, anti-Bone Morphogenetic Protein- (BMP-) 2 mAbs have been demonstrated to be efficacious in mediating bone repair in a number of bone defects. The present study sought to investigate the application of AMOR for repair of mandibular continuity defect in nonhuman primates. Critical-sized mandibular continuity defects were created in Macaca fascicularis locally implanted with absorbable collagen sponges (ACS) functionalized with chimeric anti-BMP-2 mAb or isotype control mAb. 2D and 3D analysis of cone beam computed tomography (CBCT) imaging demonstrated increased bone density and volume observed within mandibular continuity defects implanted with collagen scaffolds functionalized with anti-BMP-2 mAb, compared with isotype-matched control mAb. Both CBCT imaging and histologic examination demonstrated de novo bone formation that was in direct apposition to the margins of the resected bone. It is hypothesized that bone injury may be necessary for AMOR. This is evidenced by de novo bone formation adjacent to resected bone margins, which may be the source of endogenous BMPs captured by anti-BMP-2 mAb, in turn mediating bone repair. Yilin Xie, Yingying Su, Seiko Min, Jianxia Tang, Bee Tin Goh, Leonardo Saigo, Sahar Ansari, Alireza Moshaverinia, Chunmei Zhang, Jinsong Wang, Yi Liu, Arash Khojasteh, Homayoun H. Zadeh, and Songlin Wang Copyright © 2017 Yilin Xie et al. All rights reserved. Isolation of Mesenchymal Stem Cells from Human Deciduous Teeth Pulp Thu, 09 Mar 2017 00:00:00 +0000 This study aimed to identify predictors of success rate of mesenchymal stem cell (MSC) isolation from human deciduous teeth pulp. A total of 161 deciduous teeth were extracted at the dental clinic of Chang Gung Memorial Hospital. The MSCs were isolated from dental pulps using a standard protocol. In total, 128 colonies of MSCs were obtained and the success rate was 79.5%. Compared to teeth not yielding MSCs successfully, those successfully yielding MSCs were found to have less severe dental caries (no/mild-to-moderate/severe: 63.3/24.2/12.5% versus 12.5/42.4/42.4%, ) and less frequent pulpitis (no/yes: 95.3/4.7% versus 51.5/48.5%, ). In a multivariate regression model, it was confirmed that the absence of dental caries (OR = 4.741, 95% CI = 1.564–14.371, ) and pulpitis (OR = 9.111, 95% CI = 2.921–28.420, ) was significant determinants of the successful procurement of MSCs. MSCs derived from pulps with pulpitis expressed longer colony doubling time than pulps without pulpitis. Furthermore, there were higher expressions of proinflammatory cytokines, interleukin- (IL-) 6 and monocyte chemoattractant protein- (MCP-) 1, , and innate immune response [toll-like receptor 1 (TLR1) and TLR8, ; TLR2, TLR3, and TLR6, ] in the inflamed than noninflamed pulps. Therefore, a carious deciduous tooth or tooth with pulpitis was relatively unsuitable for MSC processing and isolation. Aileen I. Tsai, Hsiang-Hsi Hong, Wey-Ran Lin, Jen-Fen Fu, Chih-Chun Chang, I-Kuan Wang, Wen-Hung Huang, Cheng-Hao Weng, Ching-Wei Hsu, and Tzung-Hai Yen Copyright © 2017 Aileen I. Tsai et al. All rights reserved. Monitoring the Changes of Material Properties at Bone-Implant Interface during the Healing Process In Vivo: A Viscoelastic Investigation Wed, 08 Mar 2017 06:59:52 +0000 The aim of this study was to monitor the changes of viscoelastic properties at bone-implant interface via resonance frequency analysis (RFA) and the Periotest device during the healing process in an experimental rabbit model. Twenty-four dental implants were inserted into the femoral condyles of rabbits. The animals were sacrificed immediately after implant installation or on day 14, 28, or 56 after surgery. Viscoelastic properties at bone-implant interface were evaluated by measuring the implant stability quotient (ISQ) using RFA and by measuring the Periotest values (PTVs) using the Periotest device. The bone/implant specimens were evaluated histopathologically and histomorphometrically to determine the degree of osseointegration (BIC%). The BIC% values at different time points were then compared with the corresponding ISQ values and PTVs. The mean ISQ value increased gradually and reached on day 56, whereas the mean PTV decreased over time, finally reaching − on day 56. Significant correlations were found between ISQ and BIC% (, ), PTV and BIC% (, ), and ISQ and PTV (, ). These results show that there is a positive correlation between implant stability parameters and peri-implant-bone healing, indicating that the RFA and Periotest are useful for measuring changes of viscoelastic properties at bone-implant interface and are reliable for indirectly predicting the degree of osseointegration. Hsiang-Ho Chen, Wei-Yi Lai, Tze-Jian Chee, Ya-Hui Chan, and Sheng-Wei Feng Copyright © 2017 Hsiang-Ho Chen et al. All rights reserved. Maxillary Sinus Augmentation with Decellularized Bovine Compact Particles: A Radiological, Clinical, and Histologic Report of 4 Cases Thu, 02 Mar 2017 00:00:00 +0000 Background. One of the most problematic regions for endosseous implants is the posterior maxilla, not only having poor bone density, but also lacking adequate vertical height as a result of sinus pneumatization. The purpose of the present study was a radiologic, histological, and histomorphometrical evaluation, in humans, of specimens retrieved from sinuses augmented with decellularized bovine compact particles, after a healing period of 6 months. Methods. Four patients, with atrophic resorbed maxillas, underwent a sinus lift augmentation with decellularized bovine compact bone from bovine femur. The size of the particles used was 0.25–1 mm. A total of four grafts and 5 biopsies were retrieved and processed to obtain thin ground sections with the Precise 1 Automated System. Results. The mean volume after graft elevation calculated for each of the 4 patients was 2106 mm3 in the immediate postoperative period (5–7 days), ranging from 1408.8 to 2946.4 mm3. In the late postoperative period (6 months) it was 2053 mm3, ranging from 1339.9 to 2808.9 mm3. Histomorphometry showed that newly formed bone was % and marrow spaces were %, while the residual graft material was %. Conclusion. In conclusion, based on the outcome of the present study, Re-Bone® can be used with success in sinus augmentation procedures and 6 months are considered an adequate time for maturation before implant placement. Antonio Scarano Copyright © 2017 Antonio Scarano. All rights reserved. In Vitro Studies on the Degradability, Bioactivity, and Cell Differentiation of PRP/AZ31B Mg Alloys Composite Scaffold Wed, 01 Mar 2017 08:17:21 +0000 In recent years, more and more methods have been developed to improve the bioactivity of the biodegradable materials in bone tissue regeneration. In present study, we used rat mesenchymal stem cells (rMSCs) to evaluate the outcomes of Mg alloys (AZ31B, Magnesium, and Aluminum) and Platelet-rich plasma (PRP)/Mg alloys on rMSCs biocompatibility and osteogenic differentiation. Water absorption experiments indicated that both bare AZ31B and PRP/AZ31B were capable of absorbing large amounts of water. But the water absorption ratio for PRP/AZ31B was significantly higher than that for bare AZ31B. The degradability experiments implied that both samples degraded at same speed. rMSCs on the surface of AZ31B distributed more and better than those on the AZ31B scaffold. In ALP activity experiment, the activity of rMSCs on the PRP/AZ31B was markedly higher than that on the AZ31B scaffolds on the 7th day and 14th day. qRT-PCR also showed that OPN and OCN were expressed in both samples. OPN and OCN expression in PRP/AZ31B sample were higher than those in bare AZ31B samples. In summary, the in vitro study implied that AZ31B combined with PRP could remarkably improve cell seeding, attachment, proliferation, and differentiation. Jian Zou, Zhongmin Shi, Hongwei Xu, and Xiaolin Li Copyright © 2017 Jian Zou et al. All rights reserved. Rapid Chondrocyte Isolation for Tissue Engineering Applications: The Effect of Enzyme Concentration and Temporal Exposure on the Matrix Forming Capacity of Nasal Derived Chondrocytes Tue, 28 Feb 2017 08:31:54 +0000 Laboratory based processing and expansion to yield adequate cell numbers had been the standard in Autologous Disc Chondrocyte Transplantation (ADCT), Allogeneic Juvenile Chondrocyte Implantation (NuQu®), and Matrix-Induced Autologous Chondrocyte Implantation (MACI). Optimizing cell isolation is a key challenge in terms of obtaining adequate cell numbers while maintaining a vibrant cell population capable of subsequent proliferation and matrix elaboration. However, typical cell yields from a cartilage digest are highly variable between donors and based on user competency. The overall objective of this study was to optimize chondrocyte isolation from cartilaginous nasal tissue through modulation of enzyme concentration exposure (750 and 3000 U/ml) and incubation time (1 and 12 h), combined with physical agitation cycles, and to assess subsequent cell viability and matrix forming capacity. Overall, increasing enzyme exposure time was found to be more detrimental than collagenase concentration for subsequent viability, proliferation, and matrix forming capacity (sGAG and collagen) of these cells resulting in nonuniform cartilaginous matrix deposition. Taken together, consolidating a 3000 U/ml collagenase digest of 1 h at a ratio of 10 ml/g of cartilage tissue with physical agitation cycles can improve efficiency of chondrocyte isolation, yielding robust, more uniform matrix formation. Srujana Vedicherla and Conor Timothy Buckley Copyright © 2017 Srujana Vedicherla and Conor Timothy Buckley. All rights reserved. Skin Tissue Engineering: Application of Adipose-Derived Stem Cells Mon, 27 Feb 2017 09:48:03 +0000 Perception of the adipose tissue has changed dramatically over the last few decades. Identification of adipose-derived stem cells (ASCs) ultimately transformed paradigm of this tissue from a passive energy depot into a promising stem cell source with properties of self-renewal and multipotential differentiation. As compared to bone marrow-derived stem cells (BMSCs), ASCs are more easily accessible and their isolation yields higher amount of stem cells. Therefore, the ASCs are of high interest for stem cell-based therapies and skin tissue engineering. Currently, freshly isolated stromal vascular fraction (SVF), which may be used directly without any expansion, was also assessed to be highly effective in treating skin radiation injuries, burns, or nonhealing wounds such as diabetic ulcers. In this paper, we review the characteristics of SVF and ASCs and the efficacy of their treatment for skin injuries and disorders. Agnes S. Klar, Jakub Zimoch, and Thomas Biedermann Copyright © 2017 Agnes S. Klar et al. All rights reserved. A Comparison of Tissue Engineering Scaffolds Incorporated with Manuka Honey of Varying UMF Thu, 23 Feb 2017 00:00:00 +0000 Purpose. Manuka honey (MH) is an antibacterial agent specific to the islands of New Zealand containing both hydrogen peroxide and a Unique Manuka Factor (UMF). Although the antibacterial properties of MH have been studied, the effect of varying UMF of MH incorporated into tissue engineered scaffolds have not. Therefore, this study was designed to compare silk fibroin cryogels and electrospun scaffolds incorporated with a 5% MH concentration of various UMF. Methods. Characteristics such as porosity, bacterial clearance and adhesion, and cytotoxicity were compared. Results. Pore diameters for all cryogels were between 51 and 60 µm, while electrospun scaffolds were 10 µm. Cryogels of varying UMF displayed clearance of approximately 0.16 cm for E. coli and S. aureus. In comparison, the electrospun scaffolds clearance ranged between 0.5 and 1 cm. A glucose release of 0.5 mg/mL was observed for the first 24 hours by all scaffolds, regardless of UMF. With respect to cytotoxicity, neither scaffold caused the cell number to drop below 20,000. Conclusions. Overall, when comparing the effects of the various UMF within the two scaffolds, no significant differences were observed. This suggests that the fabricated scaffolds in this study displayed similar bacterial effects regardless of the UMF value. Katherine R. Hixon, Tracy Lu, Sarah H. McBride-Gagyi, Blythe E. Janowiak, and Scott A. Sell Copyright © 2017 Katherine R. Hixon et al. All rights reserved. Three-Dimensional Human Cardiac Tissue Engineered by Centrifugation of Stacked Cell Sheets and Cross-Sectional Observation of Its Synchronous Beatings by Optical Coherence Tomography Wed, 22 Feb 2017 00:00:00 +0000 Three-dimensional (3D) tissues are engineered by stacking cell sheets, and these tissues have been applied in clinical regenerative therapies. The optimal fabrication technique of 3D human tissues and the real-time observation system for these tissues are important in tissue engineering, regenerative medicine, cardiac physiology, and the safety testing of candidate chemicals. In this study, for aiming the clinical application, 3D human cardiac tissues were rapidly fabricated by human induced pluripotent stem (iPS) cell-derived cardiac cell sheets with centrifugation, and the structures and beatings in the cardiac tissues were observed cross-sectionally and noninvasively by two optical coherence tomography (OCT) systems. The fabrication time was reduced to approximately one-quarter by centrifugation. The cross-sectional observation showed that multilayered cardiac cell sheets adhered tightly just after centrifugation. Additionally, the cross-sectional transmissions of beatings within multilayered human cardiac tissues were clearly detected by OCT. The observation showed the synchronous beatings of the thicker 3D human cardiac tissues, which were fabricated rapidly by cell sheet technology and centrifugation. The rapid tissue-fabrication technique and OCT technology will show a powerful potential in cardiac tissue engineering, regenerative medicine, and drug discovery research. Yuji Haraguchi, Akiyuki Hasegawa, Katsuhisa Matsuura, Mari Kobayashi, Shin-ichi Iwana, Yasuhiro Kabetani, and Tatsuya Shimizu Copyright © 2017 Yuji Haraguchi et al. All rights reserved. Cytotoxicity and Antimicrobial Effects of a New Fast-Set MTA Mon, 20 Feb 2017 12:25:54 +0000 Purpose. To compare the biocompatibility and antimicrobial effectiveness of the new Fast-Set MTA (FS-MTA) with ProRoot MTA (RS-MTA). Methods. The agar overlay method with neutral red dye was used. L929 mouse fibroblast cells were cultured. The liquid and oil extracts and solid test material were placed on the agar overlay, four samples for each material. Phenol was used as the positive control and cottonseed oil and MEM extracts were used as negative controls. Cytotoxicity was examined by measuring the zones of decolorization and evaluating cell lysis under an inverted microscope using the established criteria after 24 and 48 hours. The antimicrobial test was performed using the Kirby-Bauer disk-diffusion method against S. mutans, E. faecalis, F. nucleatum, P. gingivalis, and P. intermedia. The size of the zone of inhibition was measured in millimeters. Results. There was no zone of decolorization seen under or around the test materials for FS-MTA and RS-MTA at 24 and 48 hours. The antimicrobial test demonstrated no inhibitory effect of FS-MTA or RS-MTA on any bacterial species after 24 and 48 hours. Conclusions. There was no cytotoxicity or bacterial inhibition observed by the new Fast-Set MTA when compared to the ProRoot MTA after setting. Michelle Shin, Jung-Wei Chen, Chi-Yang Tsai, Raydolfo Aprecio, Wu Zhang, Ji Min Yochim, Naichia Teng, and Mahmoud Torabinejad Copyright © 2017 Michelle Shin et al. All rights reserved. Developing Customized Dental Miniscrew Surgical Template from Thermoplastic Polymer Material Using Image Superimposition, CAD System, and 3D Printing Thu, 09 Feb 2017 06:37:47 +0000 This study integrates cone-beam computed tomography (CBCT)/laser scan image superposition, computer-aided design (CAD), and 3D printing (3DP) to develop a technology for producing customized dental (orthodontic) miniscrew surgical templates using polymer material. Maxillary bone solid models with the bone and teeth reconstructed using CBCT images and teeth and mucosa outer profile acquired using laser scanning were superimposed to allow miniscrew visual insertion planning and permit surgical template fabrication. The customized surgical template CAD model was fabricated offset based on the teeth/mucosa/bracket contour profiles in the superimposition model and exported to duplicate the plastic template using the 3DP technique and polymer material. An anterior retraction and intrusion clinical test for the maxillary canines/incisors showed that two miniscrews were placed safely and did not produce inflammation or other discomfort symptoms one week after surgery. The fitness between the mucosa and template indicated that the average gap sizes were found smaller than 0.5 mm and confirmed that the surgical template presented good holding power and well-fitting adaption. This study addressed integrating CBCT and laser scan image superposition; CAD and 3DP techniques can be applied to fabricate an accurate customized surgical template for dental orthodontic miniscrews. Yu-Tzu Wang, Jian-Hong Yu, Lun-Jou Lo, Pin-Hsin Hsu, and CHun-Li Lin Copyright © 2017 Yu-Tzu Wang et al. All rights reserved. Early Bone Formation around Immediately Loaded Transitional Implants Inserted in the Human Posterior Maxilla: The Effects of Fixture Design and Surface Thu, 09 Feb 2017 00:00:00 +0000 Aim. To evaluate the effects of fixture design and surface on the early bone formation around immediately loaded implants inserted in the human posterior maxilla. Materials and Methods. Ten totally edentulous subjects received two transitional implants: one tapered implant with knife-edge threads/nanostructured calcium-incorporated surface (test: Anyridge®, Megagen, Gyeongbuk, South Korea) and one cylindrical implant with self-tapping threads/sandblasted surface (control: EZPlus®, Megagen). The implants were placed according to a split-mouth design and immediately loaded to support an interim complete denture; after 8 weeks, they were removed for histologic/histomorphometric analysis. The bone-to-implant contact (BIC%) and the bone density (BD%) were calculated. The Wilcoxon test was used to evaluate the differences. Results. With test implants, a mean BIC% and BD% of 35.9 (±9.1) and 31.8 (±7.5) were found. With control implants, a mean BIC% and BD% of 29.9 (±7.6) and 32.5 (±3.9) were found. The mean BIC% was higher with test implants, but this difference was not significant (). Similar BD% were found in the two groups (). Conclusions. In the posterior maxilla, under immediate loading conditions, implants with a knife-edge thread design/nanostructured calcium-incorporated surface seem to increase the peri-implant endosseous healing properties, when compared to implants with self-tapping thread design/sandblasted surface. Carlo Mangano, Jamil Awad Shibli, Jefferson Trabach Pires, Giuseppe Luongo, Adriano Piattelli, and Giovanna Iezzi Copyright © 2017 Carlo Mangano et al. All rights reserved. Repair of Osteochondral Defects Using Human Umbilical Cord Wharton’s Jelly-Derived Mesenchymal Stem Cells in a Rabbit Model Sun, 05 Feb 2017 10:08:59 +0000 Umbilical cord Wharton’s jelly-derived mesenchymal stem cell (WJMSC) is a new-found mesenchymal stem cell in recent years with multiple lineage potential. Due to its abundant resources, no damage procurement, and lower immunogenicity than other adult MSCs, WJMSC promises to be a good xenogenous cell candidate for tissue engineering. This in vivo pilot study explored the use of human umbilical cord Wharton’s jelly mesenchymal stem cells (hWJMSCs) containing a tissue engineering construct xenotransplant in rabbits to repair full-thickness cartilage defects in the femoral patellar groove. We observed orderly spatial-temporal remodeling of hWJMSCs into cartilage tissues during repair over 16 months, with characteristic architectural features, including a hyaline-like neocartilage layer with good surface regularity, complete integration with adjacent host cartilage, and regenerated subchondral bone. No immune rejection was detected when xenograft hWJMSCs were implanted into rabbit cartilage defects. The repair results using hWJMSCs were superior to those of chondrogenically induced hWJMSCs after assessing gross appearance and histological grading scores. These preliminary results suggest that using novel undifferentiated hWJMSCs as seed cells might be a better approach than using transforming growth factor-β-induced differentiated hWJMSCs for in vivo tissue engineering treatment of cartilage defects. hWJMSC allografts may be promising for clinical applications. Shuyun Liu, Yanhui Jia, Mei Yuan, Weimin Guo, Jingxiang Huang, Bin Zhao, Jiang Peng, Wenjing Xu, Shibi Lu, and Quanyi Guo Copyright © 2017 Shuyun Liu et al. All rights reserved. Fixed Full Arches Supported by Tapered Implants with Knife-Edge Thread Design and Nanostructured, Calcium-Incorporated Surface: A Short-Term Prospective Clinical Study Sun, 29 Jan 2017 00:00:00 +0000 Purpose. To evaluate implant survival, peri-implant bone loss, and complications affecting fixed full-arch (FFA) restorations supported by implants with a knife-edge thread design and nanostructured, calcium-incorporated surface. Methods. Between January 2013 and December 2015, all patients referred for implant-supported FFA restorations were considered for enrollment in this study. All patients received implants with a knife-edge thread design and nanostructured calcium-incorporated surface (Anyridge®, Megagen, South Korea) were restored with FFA restorations and enrolled in a recall program. The final outcomes were implant survival, peri-implant bone loss, biologic/prosthetic complications, and “complication-free” survival of restorations. Results. Twenty-four patients were selected. Overall, 215 implants were inserted (130 maxilla, 85 mandible), 144 in extraction sockets and 71 in healed ridges. Thirty-six FFAs were delivered (21 maxilla, 15 mandible): 27 were immediately loaded and 9 were conventionally loaded. The follow-up ranged from 1 to 3 years. Two fixtures failed, yielding an implant survival rate of 95.9% (patient-based). A few complications were registered, for a “complication-free” survival of restorations of 88.9%. Conclusions. FFA restorations supported by implants with a knife-edge thread design and nanostructured, calcium-incorporated surface are successful in the short term, with high survival and low complication rates; long-term studies are needed to confirm these outcomes. Soheil Bechara, Algirdas Lukosiunas, Giorgio Andrea Dolcini, and Ricardas Kubilius Copyright © 2017 Soheil Bechara et al. All rights reserved. Tissue Engineering: From Basic Sciences to Clinical Perspectives Mon, 23 Jan 2017 09:32:31 +0000 Pornanong Aramwit, Antonella Motta, and Subhas C. Kundu Copyright © 2017 Pornanong Aramwit et al. All rights reserved. In Vitro and In Vivo Evaluation of Commercially Available Fibrin Gel as a Carrier of Alendronate for Bone Tissue Engineering Sun, 22 Jan 2017 00:00:00 +0000 Alendronate (ALN) is a bisphosphonate drug that is widely used for the treatment of osteoporosis. Furthermore, local delivery of ALN has the potential to improve the bone regeneration. This study was designed to investigate an ALN-containing fibrin (fibrin/ALN) gel and evaluate the effect of this gel on both in vitro cellular behavior using human mesenchymal stem cells (hMSCs) and in vivo bone regenerative capacity. Fibrin hydrogels were fabricated using various ALN concentrations (10−7–10−4 M) with fibrin glue and the morphology, mechanical properties, and ALN release kinetics were characterized. Proliferation and osteogenic differentiation of and cytotoxicity in fibrin/ALN gel-embedded hMSCs were examined. In vivo bone formation was evaluated using a rabbit calvarial defect model. The fabricated fibrin/ALN gel was transparent with Young’s modulus of ~13 kPa, and these properties were not affected by ALN concentration. The in vitro studies showed sustained release of ALN from the fibrin gel and revealed that hMSCs cultured in fibrin/ALN gel showed significantly increased proliferation and osteogenic differentiation. In addition, microcomputed tomography and histological analysis revealed that the newly formed bone was significantly enhanced by implantation of fibrin/ALN gel in a calvarial defect model. These results suggest that fibrin/ALN has the potential to improve bone regeneration. Beom Su Kim, Feride Shkembi, and Jun Lee Copyright © 2017 Beom Su Kim et al. All rights reserved. Design and Validation of Equiaxial Mechanical Strain Platform, EQUicycler, for 3D Tissue Engineered Constructs Thu, 12 Jan 2017 09:36:30 +0000 It is crucial to replicate the micromechanical milieu of native tissues to achieve efficacious tissue engineering and regenerative therapy. In this study, we introduced an innovative loading platform, EQUicycler, that utilizes a simple, yet effective, and well-controlled mechanism to apply physiologically relevant homogenous mechanical equiaxial strain on three-dimensional cell-embedded tissue scaffolds. The design of EQUicycler ensured elimination of gripping effects through the use of biologically compatible silicone posts for direct transfer of the mechanical load to the scaffolds. Finite Element Modeling (FEM) was created to understand and to quantify how much applied global strain was transferred from the loading mechanism to the tissue constructs. In vitro studies were conducted on various cell lines associated with tissues exposed to equiaxial mechanical loading in their native environment. In vitro results demonstrated that EQUicycler was effective in maintaining and promoting the viability of different musculoskeletal cell lines and upregulating early differentiation of osteoprogenitor cells. By utilizing EQUicycler, collagen fibers of the constructs were actively remodeled. Residing cells within the collagen construct elongated and aligned with strain direction upon mechanical loading. EQUicycler can provide an efficient and cost-effective tool to conduct mechanistic studies for tissue engineered constructs designed for tissue systems under mechanical loading in vivo. Mostafa Elsaadany, Matthew Harris, and Eda Yildirim-Ayan Copyright © 2017 Mostafa Elsaadany et al. All rights reserved. Tissue Engineering and Oral Rehabilitation in the Stomatognathic System Tue, 10 Jan 2017 08:58:24 +0000 Tomasz Gedrange, Christiane Kunert-Keil, Friedhelm Heinemann, and Marzena Dominiak Copyright © 2017 Tomasz Gedrange et al. All rights reserved. Laminin-521 Promotes Rat Bone Marrow Mesenchymal Stem Cell Sheet Formation on Light-Induced Cell Sheet Technology Mon, 09 Jan 2017 09:10:22 +0000 Rat bone marrow mesenchymal stem cell sheets (rBMSC sheets) are attractive for cell-based tissue engineering. However, methods of culturing rBMSC sheets are critically limited. In order to obtain intact rBMSC sheets, a light-induced cell sheet method was used in this study. TiO2 nanodot films were coated with (TL) or without (TN) laminin-521. We investigated the effects of laminin-521 on rBMSCs during cell sheet culturing. The fabricated rBMSC sheets were subsequently assessed to study cell sheet viability, reattachment ability, cell sheet thickness, collagen type I deposition, and multilineage potential. The results showed that laminin-521 could promote the formation of rBMSC sheets with good viability under hyperconfluent conditions. Cell sheet thickness increased from an initial 26.7 ± 1.5 μm (day 5) up to 47.7 ± 3.0 μm (day 10). Moreover, rBMSC sheets maintained their potential of osteogenic, adipogenic, and chondrogenic differentiation. This study provides a new strategy to obtain rBMSC sheets using light-induced cell sheet technology. Zhiwei Jiang, Yue Xi, Kaichen Lai, Ying Wang, Huiming Wang, and Guoli Yang Copyright © 2017 Zhiwei Jiang et al. All rights reserved. Analysis of the Osteogenic Effects of Biomaterials Using Numerical Simulation Mon, 02 Jan 2017 08:02:38 +0000 We describe the development of an optimization algorithm for determining the effects of different properties of implanted biomaterials on bone growth, based on the finite element method and bone self-optimization theory. The rate of osteogenesis and the bone density distribution of the implanted biomaterials were quantitatively analyzed. Using the proposed algorithm, a femur with implanted biodegradable biomaterials was simulated, and the osteogenic effects of different materials were measured. Simulation experiments mainly considered variations in the elastic modulus (20–3000 MPa) and degradation period (10, 20, and 30 days) for the implanted biodegradable biomaterials. Based on our algorithm, the osteogenic effects of the materials were optimal when the elastic modulus was 1000 MPa and the degradation period was 20 days. The simulation results for the metaphyseal bone of the left femur were compared with micro-CT images from rats with defective femurs, which demonstrated the effectiveness of the algorithm. The proposed method was effective for optimization of the bone structure and is expected to have applications in matching appropriate bones and biomaterials. These results provide important insights into the development of implanted biomaterials for both clinical medicine and materials science. Lan Wang, Jie Zhang, Wen Zhang, Hui-Lin Yang, and Zong-Ping Luo Copyright © 2017 Lan Wang et al. All rights reserved. Fabrication of Novel Hydrogel with Berberine-Enriched Carboxymethylcellulose and Hyaluronic Acid as an Anti-Inflammatory Barrier Membrane Thu, 29 Dec 2016 13:32:17 +0000 An antiadhesion barrier membrane is an important biomaterial for protecting tissue from postsurgical complications. However, there is room to improve these membranes. Recently, carboxymethylcellulose (CMC) incorporated with hyaluronic acid (HA) as an antiadhesion barrier membrane and drug delivery system has been reported to provide excellent tissue regeneration and biocompatibility. The aim of this study was to fabricate a novel hydrogel membrane composed of berberine-enriched CMC prepared from bark of the P. amurense tree and HA (PE-CMC/HA). In vitro anti-inflammatory properties were evaluated to determine possible clinical applications. The PE-CMC/HA membranes were fabricated by mixing PE-CMC and HA as a base with the addition of polyvinyl alcohol to form a film. Tensile strength and ultramorphology of the membrane were evaluated using a universal testing machine and scanning electron microscope, respectively. Berberine content of the membrane was confirmed using a UV-Vis spectrophotometer at a wavelength of 260 nm. Anti-inflammatory property of the membrane was measured using a Griess reaction assay. Our results showed that fabricated PE-CMC/HA releases berberine at a concentration of 660 μg/ml while optimal plasticity was obtained at a 30 : 70 PE-CMC/HA ratio. The berberine-enriched PE-CMC/HA had an inhibited 60% of inflammation stimulated by LPS. These results suggest that the PE-CMC/HA membrane fabricated in this study is a useful anti-inflammatory berberine release system. Yu-Chih Huang, Kuen-Yu Huang, Bing-Yuan Yang, Chun-Han Ko, and Haw-Ming Huang Copyright © 2016 Yu-Chih Huang et al. All rights reserved. UV Photofunctionalization Effect on Bone Graft in Critical One-Wall Defect around Implant: A Pilot Study in Beagle Dogs Wed, 28 Dec 2016 09:23:35 +0000 The purpose of this study was to compare and evaluate, through histomorphometric and radiological analysis, the effects of UV photofunctionalization on an implant placed over a critical defect area with and without a bone graft. Four female beagle dogs were first divided into control and bone graft groups. Each group was then subdivided into UV-treated and UV-untreated groups. The mandibular premolars in each dog were extracted. 12 weeks after extraction, implants were placed according to the condition of each group. Four and 12 weeks after implantation on left and right mandible, the dogs were sacrificed. The specimens were prepared for histomorphometric and micro-computed tomographic analysis. In both 4-week and 12-week groups, UV-treated implant surfaces showed better osseointegration than SA implant surfaces. Also, with implant surfaces placed over the critical defect with bone graft, UV photofunctionalization increased bone-to-implant contact (BIC) and new bone formation at the initial stage (4 weeks). Based on the results of this study, it can be suggested that UV photofunctionalization on the surface of implants placed over large critical defects with bone graft aids initial osseointegration and osteogenesis. Min-Young Kim, Hyunmin Choi, Jae-Hoon Lee, Jee-Hwan Kim, Han-Sung Jung, Jae-Hong Kim, Young-Bum Park, and Hong-Seok Moon Copyright © 2016 Min-Young Kim et al. All rights reserved. Potential Osteoinductive Effects of Calcitriol on the m-RNA of Mesenchymal Stem Cells Derived from Human Alveolar Periosteum Sun, 25 Dec 2016 12:18:49 +0000 This study characterized alveolar periosteum-derived mesenchymal stem cells (P-MSCs) and examined the hypothesis that 1,25-(OH)2D3 (calcitriol) exerts osteoinductive effects on P-MSCs. The mRNA expressions of alkaline phosphatase (ALP), bone sialoprotein (BSP), core-binding factor alpha-1 (CBFA1), collagen-1 (Col-1), osteocalcin (OCN), and vitamin D3 receptor (VDR) were assessed after incubation with calcitriol for 2 weeks. Vitamin C as positive control (Vit. C-p) increased ALP and CBFA1 mRNA expression at both 1 and 2 weeks and increased BSP and Col-1 mRNA expression only at the first week. A concentration of 10−8 M calcitriol enhanced ALP, CBFA1, Col-1, and OCN mRNA expression at both weeks and BSP mRNA expression at the first week. Furthermore, 10−7 M calcitriol increased the mRNA expressions of all compounds at both weeks, except that of CBFA1 at the first week. 10−8 M calcitriol and Vit. C-p enhanced ALP activity at the second and third weeks. The results revealed that 10−9, 10−8, and 10−7 M calcitriol induced osteoinduction in alveolar P-MSCs by increasing ALP, CBFA1, Col-1, and OCN mRNA expression. A 10−7 M calcitriol yielded a higher mRNA expression than Vit. Cp on VDR and OCN mRNA expression at both weeks and on Col-1 mRNA at the second week. Hsiang-Hsi Hong, Adrienne Hong, Tzung-Hai Yen, and Yen-Li Wang Copyright © 2016 Hsiang-Hsi Hong et al. All rights reserved. Placenta Derived Mesenchymal Stem Cells Hosted on RKKP Glass-Ceramic: A Tissue Engineering Strategy for Bone Regenerative Medicine Applications Mon, 19 Dec 2016 08:01:18 +0000 In tissue engineering protocols, the survival of transplanted stem cells is a limiting factor that could be overcome using a cell delivery matrix able to support cell proliferation and differentiation. With this aim, we studied the cell-friendly and biocompatible behavior of RKKP glass-ceramic coated Titanium (Ti) surface seeded with human amniotic mesenchymal stromal cells (hAMSCs) from placenta. The sol-gel synthesis procedure was used to prepare the RKKP glass-ceramic material, which was then deposited onto the Ti surface by Pulsed Laser Deposition method. The cell metabolic activity and proliferation rate, the cytoskeletal actin organization, and the cell cycle phase distribution in hAMSCs seeded on the RKKP coated Ti surface revealed no significant differences when compared to the cells grown on the treated plastic Petri dish. The health of of hAMSCs was also analysed studying the mRNA expressions of MSC key genes and the osteogenic commitment capability using qRT-PCR analysis which resulted in being unchanged in both substrates. In this study, the combination of the hAMSCs’ properties together with the bioactive characteristics of RKKP glass-ceramics was investigated and the results obtained indicate its possible use as a new and interesting cell delivery system for bone tissue engineering and regenerative medicine applications. Mario Ledda, Marco Fosca, Angela De Bonis, Mariangela Curcio, Roberto Teghil, Maria Grazia Lolli, Adriana De Stefanis, Rodolfo Marchese, Julietta V. Rau, and Antonella Lisi Copyright © 2016 Mario Ledda et al. All rights reserved. Periosteal Distraction Osteogenesis: An Effective Method for Bone Regeneration Sun, 18 Dec 2016 10:14:57 +0000 The treatment of bone defects is challenging and controversial. As a new technology, periosteal distraction osteogenesis (PDO) uses the osteogenicity of periosteum, which creates an artificial space between the bone surface and periosteum to generate new bone by gradually expanding the periosteum with no need for corticotomy. Using the newly formed bone of PDO to treat bone defects is effective, which can not only avoid the occurrence of immune-related complications, but also solve the problem of insufficient donor. This review elucidates the availability of PDO in the aspects of mechanisms, devices, strategies, and measures. Moreover, we also focus on the future prospects of PDO and hope that PDO will be applied to the clinical treatment of bone defects in the future. Danyang Zhao, Yu Wang, and Dong Han Copyright © 2016 Danyang Zhao et al. All rights reserved. Bone Healing Improvements Using Hyaluronic Acid and Hydroxyapatite/Beta-Tricalcium Phosphate in Combination: An Animal Study Wed, 14 Dec 2016 13:40:13 +0000 The purpose of this study was to investigate whether the use of HLA as an aqueous binder of hydroxyapatite/beta-tricalcium phosphate (HA-βTCP) particles can reduce the amount of bone graft needed and increase ease of handling in clinical situations. In this study, HA/βTCP was loaded in commercially available crosslinking HLA to form a novel HLA/HA-βTCP composite. Six New Zealand White rabbits (3.0–3.6 kg) were used as test subjects. Four 6 mm defects were prepared in the parietal bone. The defects were filled with the HLA/HA-βTCP composite as well as HA-βTCP particle alone. New bone formation was analyzed by micro-CT and histomorphometry. Our results indicated that even when the HA-βTCP particle numbers were reduced, the regenerative effect on bone remained when the HLA existed. The bone volume density (BV/TV ratio) of HLA/HA-βTCP samples was 1.7 times larger than that of the control sample at week 2. The new bone increasing ratio (NBIR) of HLA/HA-βTCP samples was 1.78 times higher than the control group at week 2. In conclusion, HA-βTCP powder with HLA contributed to bone healing in rabbit calvarial bone defects. The addition of HLA to bone grafts not only promoted osteoconduction but also improved handling characteristics in clinical situations. Yen-Lan Chang, Yi-June Lo, Sheng-Wei Feng, Yu-Chih Huang, Hsin-Yuan Tsai, Che-Tong Lin, Kan-Hsin Fan, and Haw-Ming Huang Copyright © 2016 Yen-Lan Chang et al. All rights reserved. Synergistic Effects of Vascular Endothelial Growth Factor on Bone Morphogenetic Proteins Induced Bone Formation In Vivo: Influencing Factors and Future Research Directions Tue, 13 Dec 2016 12:29:39 +0000 Vascular endothelial growth factor (VEGF) and bone morphogenetic proteins (BMPs), as key mediators in angiogenesis and osteogenesis, are used in a combined delivery manner as a novel strategy in bone tissue engineering. VEGF has the potential to enhance BMPs induced bone formation. Both gene delivery and material-based delivery systems were incorporated in previous studies to investigate the synergistic effects of VEGF and BMPs. However, their results were controversial due to variation of methods incorporated in different studies. Factors influencing the synergistic effects of VEGF on BMPs induced bone formation were identified and analyzed in this review to reduce confusion on this issue. The potential mechanisms and directions of future studies were also proposed here. Further investigating mechanisms of the synergistic effects and optimizing these influencing factors will help to generate more effective bone regeneration. Bo Li, Hai Wang, Guixing Qiu, Xinlin Su, and Zhihong Wu Copyright © 2016 Bo Li et al. All rights reserved. Proteomic Profiling of Neuroblastoma Cells Adhesion on Hyaluronic Acid-Based Surface for Neural Tissue Engineering Wed, 07 Dec 2016 06:21:07 +0000 The microenvironment of neuron cells plays a crucial role in regulating neural development and regeneration. Hyaluronic acid (HA) biomaterial has been applied in a wide range of medical and biological fields and plays important roles in neural regeneration. PC12 cells have been reported to be capable of endogenous NGF synthesis and secretion. The purpose of this research was to assess the effect of HA biomaterial combining with PC12 cells conditioned media (PC12 CM) in neural regeneration. Using SH-SY5Y cells as an experimental model, we found that supporting with PC12 CM enhanced HA function in SH-SY5Y cell proliferation and adhesion. Through RP-nano-UPLC-ESI-MS/MS analyses, we identified increased expression of HSP60 and RanBP2 in SH-SY5Y cells grown on HA-modified surface with cotreatment of PC12 CM. Moreover, we also identified factors that were secreted from PC12 cells and may promote SH-SY5Y cell proliferation and adhesion. Here, we proposed a biomaterial surface enriched with neurotrophic factors for nerve regeneration application. Ming-Hui Yang, Ko-Chin Chen, Pei-Wen Chiang, Tze-Wen Chung, Wan-Jou Chen, Pei-Yu Chu, Sharon Chia-Ju Chen, Yi-Shan Lu, Cheng-Hui Yuan, Ming-Chen Wang, Chia-Yang Lin, Ying-Fong Huang, Shiang-Bin Jong, Po-Chiao Lin, and Yu-Chang Tyan Copyright © 2016 Ming-Hui Yang et al. All rights reserved. Cytotoxicity of Titanate-Calcium Complexes to MC3T3 Osteoblast-Like Cells Thu, 01 Dec 2016 06:48:11 +0000 Monosodium titanates (MST) are a relatively novel form of particulate titanium dioxide that have been proposed for biological use as metal sorbents or delivery agents, most recently calcium (II). In these roles, the toxicity of the titanate or its metal complex is crucial to its biological utility. The aim of this study was to determine the cytotoxicity of MST and MST-calcium complexes with MC3T3 osteoblast-like cells; MST-Ca(II) complexes could be useful to promote bone formation in various hard tissue applications. MC3T3 cells were exposed to native MST or MST-Ca(II) complexes for 24–72 h. A CellTiter-Blue® assay was employed to assess the metabolic activity of the cells. The results showed that MST and MST-Ca(II) suppressed MC3T3 metabolic activity significantly in a dose-, time-, and cell-density-dependent fashion. MST-Ca(II) suppressed MC3T3 metabolism in a statistically identical manner as native MST at all concentrations. We concluded that MST and MST-Ca(II) are significantly cytotoxic to MC3T3 cells through a mechanism yet unknown; this is a potential problem to the biological utility of these complexes. Yen-Wei Chen, Jeanie L. Drury, Joelle Moussi, Kathryn M. L. Taylor-Pashow, David T. Hobbs, and John C. Wataha Copyright © 2016 Yen-Wei Chen et al. All rights reserved. Efficiency of Human Epiphyseal Chondrocytes with Differential Replication Numbers for Cellular Therapy Products Thu, 24 Nov 2016 12:05:16 +0000 The cell-based therapy for cartilage or bone requires a large number of cells; serial passages of chondrocytes are, therefore, needed. However, fates of expanded chondrocytes from extra fingers remain unclarified. The chondrocytes from human epiphyses morphologically changed from small polygonal cells to bipolar elongated spindle cells and to large polygonal cells with degeneration at early passages. Gene of type II collagen was expressed in the cells only at a primary culture (Passage 0) and Passage 1 (P1) cells. The nodules by implantation of P0 to P8 cells were composed of cartilage and perichondrium. The cartilage consisted of chondrocytes with round nuclei and type II collagen-positive matrix, and the perichondrium consisted of spindle cells with type I collage-positive matrix. The cartilage and perichondrium developed to bone with marrow cavity through enchondral ossification. Chondrogenesis and osteogenesis by epiphyseal chondrocytes depended on replication number in culture. It is noteworthy to take population doubling level in correlation with pharmaceutical efficacy into consideration when we use chondrocytes for cell-based therapies. Michiyo Nasu, Shinichiro Takayama, and Akihiro Umezawa Copyright © 2016 Michiyo Nasu et al. All rights reserved. Cogels of Hyaluronic Acid and Acellular Matrix for Cultivation of Adipose-Derived Stem Cells: Potential Application for Vocal Fold Tissue Engineering Thu, 17 Nov 2016 07:15:34 +0000 Stem cells based tissue engineering has been one of the potential promising therapies in the research on the repair of tissue diseases including the vocal fold. Decellularized extracellular matrix (DCM) as a promising scaffold has be used widely in tissue engineering; however, it remained to be an important issue in vocal fold regeneration. Here, we applied the hydrogels (hyaluronic acid [HA], HA-collagen [HA-Col], and HA-DCM) to determine the effects of hydrogel on the growth and differentiation of human adipose-derived stem cells (hADSCs) into superficial lamina propria fibroblasts. hADSCs were isolated and characterized by fluorescence-activated cell sorting. The results indicated that HA-DCM hydrogel enhanced cell proliferation and prolonged cell morphology significantly compared to HA and HA-Col hydrogel. Importantly, the differentiation of hADSCs into fibroblasts was also promoted by cogels of HA-Col and HA-DCM significantly. The differentiation of hADSCs towards superficial lamina propria fibroblasts was accelerated by the secretion of HGF, IL-8, and VEGF, the decorin and elastin expression, and the synthesis of chondroitin sulfate significantly. Therefore, the cogel of HA-DCM hydrogel was shown to be outstanding in apparent stimulation of hADSCs proliferation and differentiation to vocal fold fibroblasts through secretion of important growth factors and synthesis of extracellular matrix. Dongyan Huang, Rongguang Wang, and Shiming Yang Copyright © 2016 Dongyan Huang et al. All rights reserved. Assessment of Temperature Rise and Time of Alveolar Ridge Splitting by Means of Er:YAG Laser, Piezosurgery, and Surgical Saw: An Ex Vivo Study Thu, 10 Nov 2016 11:44:44 +0000 The most common adverse effect after bone cutting is a thermal damage. The aim of our study was to evaluate the bone temperature rise during an alveolar ridge splitting, rating the time needed to perform this procedure and the time to raise the temperature of a bone by 10°C, as well as to evaluate the bone carbonization occurrence. The research included 60 mandibles () of adult pigs, divided into 4 groups (). Two vertical and one horizontal cut have been done in an alveolar ridge using Er:YAG laser with set power of 200 mJ (G1), 400 mJ (G2), piezosurgery unit (G3), and a saw (G4). The temperature was measured by K-type thermocouple. The highest temperature gradient was noted for piezosurgery on the buccal and lingual side of mandible. The temperature rises on the bone surface along with the increase of laser power. The lower time needed to perform ridge splitting was measured for a saw, piezosurgery, and Er:YAG laser with power of 400 mJ and 200 mJ, respectively. The temperature rise measured on the bone over 10°C and bone carbonization occurrence was not reported in all study groups. Piezosurgery, Er:YAG laser (200 mJ and 400 mJ), and surgical saw are useful and safe tools in ridge splitting surgery. Jacek Matys, Rafał Flieger, and Marzena Dominiak Copyright © 2016 Jacek Matys et al. All rights reserved. Fabrication of Poly(-caprolactone) Scaffolds Reinforced with Cellulose Nanofibers, with and without the Addition of Hydroxyapatite Nanoparticles Mon, 31 Oct 2016 11:51:54 +0000 Biomaterial properties and controlled architecture of scaffolds are essential features to provide an adequate biological and mechanical support for tissue regeneration, mimicking the ingrowth tissues. In this study, a bioextrusion system was used to produce 3D biodegradable scaffolds with controlled architecture, comprising three types of constructs: (i) poly(ε-caprolactone) (PCL) matrix as reference; (ii) PCL-based matrix reinforced with cellulose nanofibers (CNF); and (iii) PCL-based matrix reinforced with CNF and hydroxyapatite nanoparticles (HANP). The effect of the addition and/or combination of CNF and HANP into the polymeric matrix of PCL was investigated, with the effects of the biomaterial composition on the constructs (morphological, thermal, and mechanical performances) being analysed. Scaffolds were produced using a single lay-down pattern of 0/90°, with the same processing parameters among all constructs being assured. The performed morphological analyses showed a satisfactory distribution of CNF within the polymer matrix and high reliability was obtained among the produced scaffolds. Significant effects on surface wettability and thermal properties were observed, among scaffolds. Regarding the mechanical properties, higher scaffold stiffness in the reinforced scaffolds was obtained. Results from the cytotoxicity assay suggest that all the composite scaffolds presented good biocompatibility. The results of this first study on cellulose and hydroxyapatite reinforced constructs with controlled architecture clearly demonstrate the potential of these 3D composite constructs for cell cultivation with enhanced mechanical properties. Pedro Morouço, Sara Biscaia, Tânia Viana, Margarida Franco, Cândida Malça, Artur Mateus, Carla Moura, Frederico C. Ferreira, Geoffrey Mitchell, and Nuno M. Alves Copyright © 2016 Pedro Morouço et al. All rights reserved. Use of Adipose-Derived Stem Cells to Support Topical Skin Adhesive for Wound Closure: A Preliminary Report from Animal In Vivo Study Mon, 10 Oct 2016 10:40:07 +0000 The aim of this study was to determine the local and systemic effects of adipose-derived stem cells (ADSCs) as a component of topical skin adhesive in an animal artificial wound closure model. In presented study the cosmetic effects, histological analysis, mechanical properties, and cell migration have been assessed to evaluate the usefulness of ADSCs as supporting factor for octyl blend cyanoacrylate adhesive. The total of 40 rats were used and divided into six groups. In the Study Group, ADSCs were administered by multipoint injection of the six surrounding intrawound areas with additional freely leaving procedure of the cells between the skin flaps just before applying adhesive to close the wound. Five control groups without using ADSCs, utilizing different types of standard wound closure, were created in order to check efficiency of experimental stem cell therapy. In our study, we proved that ADSCs could be used effectively also as a supportive tool in topical skin adhesive for wound closure. However we did not achieve any spectacular differences related to such aspects as better mechanical properties or special biological breakthroughs in wound healing properties. The use of stem cells, especially ADSCs for wound closure can provide an inspiring development in plastic and dermatologic surgery. Maciej Nowacki, Katarzyna Pietkun, Arkadiusz Jundziłł, Tomasz Kloskowski, Dariusz Grzanka, Joanna Skopinska-Wisniewska, Kinga Scibior, Maciej Gagat, Marta Pokrywczyńska, Alina Grzanka, Wojciech Zegarski, Rafał Czajkowski, Tomasz Drewa, and Barbara Zegarska Copyright © 2016 Maciej Nowacki et al. All rights reserved. The Alteration of the Epidermal Basement Membrane Complex of Human Nevus Tissue and Keratinocyte Attachment after High Hydrostatic Pressurization Mon, 26 Sep 2016 14:09:57 +0000 We previously reported that human nevus tissue was inactivated after high hydrostatic pressure (HHP) higher than 200 MPa and that human cultured epidermis (hCE) engrafted on the pressurized nevus at 200 MPa but not at 1000 MPa. In this study, we explore the changes to the epidermal basement membrane in detail and elucidate the cause of the difference in hCE engraftment. Nevus specimens of 8 mm in diameter were divided into five groups (control and 100, 200, 500, and 1000 MPa). Immediately after HHP, immunohistochemical staining was performed to detect the presence of laminin-332 and type VII collagen, and the specimens were observed by transmission electron microscopy (TEM). hCE was placed on the pressurized nevus specimens in the 200, 500, and 1000 MPa groups and implanted into the subcutis of nude mice; the specimens were harvested at 14 days after implantation. Then, human keratinocytes were seeded on the pressurized nevus and the attachment was evaluated. The immunohistochemical staining results revealed that the control and 100 MPa, 200 MPa, and 500 MPa groups were positive for type VII collagen and laminin-332 immediately after HHP. TEM showed that, in all of the groups, the lamina densa existed; however, anchoring fibrils were not clearly observed in the 500 or 1000 MPa groups. Although the hCE took in the 200 and 500 MPa groups, keratinocyte attachment was only confirmed in the 200 MPa group. This result indicates that HHP at 200 MPa is preferable for inactivating nevus tissue to allow its reuse for skin reconstruction in the clinical setting. Naoki Morimoto, Chizuru Jinno, Atsushi Mahara, Michiharu Sakamoto, Natsuko Kakudo, Masukazu Inoie, Toshia Fujisato, Shigehiko Suzuki, Kenji Kusumoto, and Tetsuji Yamaoka Copyright © 2016 Naoki Morimoto et al. All rights reserved. Angiogenic Effects of Collagen/Mesoporous Nanoparticle Composite Scaffold Delivering VEGF165 Mon, 05 Sep 2016 11:00:22 +0000 Vascularization is a key issue for the success of tissue engineering to repair damaged tissue. In this study, we report a composite scaffold delivering angiogenic factor for this purpose. Vascular endothelial growth factor (VEGF) was loaded on mesoporous silica nanoparticle (MSN), which was then incorporated within a type I collagen sponge, to produce collagen/MSN/VEGF (CMV) scaffold. The CMV composite scaffold could release VEGF sustainably over the test period of 28 days. The release of VEGF improved the cell proliferation. Moreover, the in vivo angiogenesis of the scaffold, as studied by the chick chorioallantoic membrane (CAM) model, showed that the VEGF-releasing scaffold induced significantly increased number of blood vessel complexes when compared with VEGF-free scaffold. The composite scaffold showed good biocompatibility, as examined in rat subcutaneous tissue. These results demonstrate that the CMV scaffold with VEGF-releasing capacity can be potentially used to stimulate angiogenesis and tissue repair. Joong-Hyun Kim, Tae-Hyun Kim, Min Sil Kang, and Hae-Won Kim Copyright © 2016 Joong-Hyun Kim et al. All rights reserved. Hypothyroidism Affects Olfactory Evoked Potentials Tue, 30 Aug 2016 06:05:06 +0000 Background. Objective electrophysiological methods for investigations of the organ of smell consist in recordings of olfactory cortex responses to specific, time restricted odor stimuli. In hypothyroidism have impaired sense of smell. Material and Methods. Two groups: control of 31 healthy subjects and study group of 21 with hypothyroidism. The inclusion criterion for the study group was the TSH range from 3.54 to 110 μIU/mL. Aim. Assessment of the latency time of evoked responses from the olfactory nerve N1 and the trigeminal nerve N5 using two smells of mint and anise in hypothyroidism. Results. The smell perception in subjective olfactory tests was normal in 85% of the hypothyroid group. Differences were noticed in the objective tests. The detailed intergroup analysis of latency times of recorded cortical responses and performed by means between the groups of patients with overt clinical hypothyroidism versus subclinical hypothyroidism demonstrated a significant difference () whereas no such differences were found between the control group versus subclinical hypothyroidism group (). Conclusion. We can conclude that registration of cortex potentials at irritation of olfactory and trigeminal nerves offers possibilities for using this method as an objective indicator of hypothyroidism severity and prognostic process factor. Teodor Świdziński, Kamila Linkowska-Świdzińska, Hanna Czerniejewska-Wolska, Bożena Wiskirska-Woźnica, Maciej Owecki, Maria Danuta Głowacka, Anna Frankowska, Katarzyna Łącka, Mariusz Glapiński, Zofia Maciejewska-Szaniec, and Piotr Świdziński Copyright © 2016 Teodor Świdziński et al. All rights reserved. Synergistic Effect of Mesoporous Silica and Hydroxyapatite in Loaded Poly(DL-lactic-co-glycolic acid) Microspheres on the Regeneration of Bone Defects Mon, 29 Aug 2016 06:04:18 +0000 A microsphere composite made of poly(DL-lactic-co-glycolic acid) (PLGA), mesoporous silica nanoparticle (MSN), and nanohydroxyapatite (nHA) (PLGA-MSN/nHA) was prepared and evaluated as bone tissue engineering materials. The objective of this study was to investigate the synergistic effect of MSN/nHA on biocompatibility as well as its potential ability for bone formation. First, we found that this PLGA-MSN/nHA composite performed good characteristics on microstructure, mechanical strength, and wettability. By cell culture experiments, the adhesion and proliferation rate of the cells seeded on PLGA-MSN/nHA composite was higher than those of the controls and high levels of osteogenetic factors such as ALP and Runx-2 were detected by reverse transcriptase polymerase chain reaction. Finally, this PLGA-MSN/nHA composite was implanted into the femur bone defect in a rabbit model, and its ability to induce bone regeneration was observed by histological examinations. Twelve weeks after implantation, the bone defects had significantly more formation of mature bone and less residual materials than in the controls. These results demonstrate that this PLGA-MSN/nHA composite, introducing both MSN and nHA into PLGA microspheres, can improve the biocompatibility and osteoinductivity of composite in vitro and in vivo and had potential application in bone regeneration. Shu He, Kai-Feng Lin, Jun-Jun Fan, Gang Hu, Xin Dong, Yi-Nan Zhao, Yue Song, Zhong-Shang Guo, Long Bi, and Jian Liu Copyright © 2016 Shu He et al. All rights reserved. Embryoid Body-Explant Outgrowth Cultivation from Induced Pluripotent Stem Cells in an Automated Closed Platform Sun, 28 Aug 2016 14:11:50 +0000 Automation of cell culture would facilitate stable cell expansion with consistent quality. In the present study, feasibility of an automated closed-cell culture system “P 4C S” for an embryoid body- (EB-) explant outgrowth culture was investigated as a model case for explant culture. After placing the induced pluripotent stem cell- (iPSC-) derived EBs into the system, the EBs successfully adhered to the culture surface and the cell outgrowth was clearly observed surrounding the adherent EBs. After confirming the outgrowth, we carried out subculture manipulation, in which the detached cells were simply dispersed by shaking the culture flask, leading to uniform cell distribution. This enabled continuous stable cell expansion, resulting in a cell yield of 3.1 × 107. There was no evidence of bacterial contamination throughout the cell culture experiments. We herewith developed the automated cultivation platform for EB-explant outgrowth cells. Hiroshi Tone, Saeko Yoshioka, Hirokazu Akiyama, Akira Nishimura, Masaki Ichimura, Masaru Nakatani, Tohru Kiyono, Masashi Toyoda, Masatoshi Watanabe, and Akihiro Umezawa Copyright © 2016 Hiroshi Tone et al. All rights reserved. Hydrogel-Based Controlled Delivery Systems for Articular Cartilage Repair Tue, 23 Aug 2016 15:28:35 +0000 Delivery of bioactive factors is a very valuable strategy for articular cartilage repair. Nevertheless, the direct supply of such biomolecules is limited by several factors including rapid degradation, the need for supraphysiological doses, the occurrence of immune and inflammatory responses, and the possibility of dissemination to nontarget sites that may impair their therapeutic action and raise undesired effects. The use of controlled delivery systems has the potential of overcoming these hurdles by promoting the temporal and spatial presentation of such factors in a defined target. Hydrogels are promising materials to develop delivery systems for cartilage repair as they can be easily loaded with bioactive molecules controlling their release only where required. This review exposes the most recent technologies on the design of hydrogels as controlled delivery platforms of bioactive molecules for cartilage repair. Ana Rey-Rico, Henning Madry, and Magali Cucchiarini Copyright © 2016 Ana Rey-Rico et al. All rights reserved. Applications of Chondrocyte-Based Cartilage Engineering: An Overview Thu, 18 Aug 2016 08:57:26 +0000 Chondrocytes are the exclusive cells residing in cartilage and maintain the functionality of cartilage tissue. Series of biocomponents such as different growth factors, cytokines, and transcriptional factors regulate the mesenchymal stem cells (MSCs) differentiation to chondrocytes. The number of chondrocytes and dedifferentiation are the key limitations in subsequent clinical application of the chondrocytes. Different culture methods are being developed to overcome such issues. Using tissue engineering and cell based approaches, chondrocytes offer prominent therapeutic option specifically in orthopedics for cartilage repair and to treat ailments such as tracheal defects, facial reconstruction, and urinary incontinence. Matrix-assisted autologous chondrocyte transplantation/implantation is an improved version of traditional autologous chondrocyte transplantation (ACT) method. An increasing number of studies show the clinical significance of this technique for the chondral lesions treatment. Literature survey was carried out to address clinical and functional findings by using various ACT procedures. The current study was conducted to study the pharmacological significance and biomedical application of chondrocytes. Furthermore, it is inferred from the present study that long term follow-up studies are required to evaluate the potential of these methods and specific positive outcomes. Abdul-Rehman Phull, Seong-Hui Eo, Qamar Abbas, Madiha Ahmed, and Song Ja Kim Copyright © 2016 Abdul-Rehman Phull et al. All rights reserved. Bone Regeneration after Treatment with Covering Materials Composed of Flax Fibers and Biodegradable Plastics: A Histological Study in Rats Thu, 11 Aug 2016 14:38:10 +0000 The aim of this study was to examine the osteogenic potential of new flax covering materials. Bone defects were created on the skull of forty rats. Materials of pure PLA and PCL and their composites with flax fibers, genetically modified producing PHB (PLA-transgen, PCL-transgen) and unmodified (PLA-wt, PCL-wt), were inserted. The skulls were harvested after four weeks and subjected to histological examination. The percentage of bone regeneration by using PLA was less pronounced than after usage of pure PCL in comparison with controls. After treatment with PCL-transgen, a large amount of new formed bone could be found. In contrast, PCL-wt decreased significantly the bone regeneration, compared to the other tested groups. The bone covers made of pure PLA had substantially less influence on bone regeneration and the bone healing proceeded with a lot of connective tissue, whereas PLA-transgen and PLA-wt showed nearly comparable amount of new formed bone. Regarding the histological data, the hypothesis could be proposed that PCL and its composites have contributed to a higher quantity of the regenerated bone, compared to PLA. The histological studies showed comparable bone regeneration processes after treatment with tested covering materials, as well as in the untreated bone lesions. Tomasz Gredes, Franziska Kunath, Tomasz Gedrange, and Christiane Kunert-Keil Copyright © 2016 Tomasz Gredes et al. All rights reserved. Influence of Botulinumtoxin A on the Expression of Adult MyHC Isoforms in the Masticatory Muscles in Dystrophin-Deficient Mice (Mdx-Mice) Sun, 07 Aug 2016 06:25:57 +0000 The most widespread animal model to investigate Duchenne muscular dystrophy is the mdx-mouse. In contrast to humans, phases of muscle degeneration are replaced by regeneration processes; hence there is only a restricted time slot for research. The aim of the study was to investigate if an intramuscular injection of BTX-A is able to break down muscle regeneration and has direct implications on the gene expression of myosin heavy chains in the corresponding treated and untreated muscles. Therefore, paralysis of the right masseter muscle was induced in adult healthy and dystrophic mice by a specific intramuscular injection of BTX-A. After 21 days the mRNA expression and protein content of MyHC isoforms of the right and left masseter, temporal, and the tongue muscle were determined using quantitative RT-PCR and Western blot technique. MyHC-IIa and MyHC-I-mRNA expression significantly increased in the paralyzed masseter muscle of control-mice, whereas MyHC-IIb and MyHC-IIx/d-mRNA were decreased. In dystrophic muscles no effect of BTX-A could be detected at the level of MyHC. This study suggests that BTX-A injection is a suitable method to simulate DMD-pathogenesis in healthy mice but further investigations are necessary to fully analyse the BTX-A effect and to generate sustained muscular atrophy in mdx-mice. Ute Ulrike Botzenhart, Constantin Wegenstein, Teodor Todorov, and Christiane Kunert-Keil Copyright © 2016 Ute Ulrike Botzenhart et al. All rights reserved. Approaches to Peripheral Nerve Repair: Generations of Biomaterial Conduits Yielding to Replacing Autologous Nerve Grafts in Craniomaxillofacial Surgery Sun, 31 Jul 2016 13:45:55 +0000 Peripheral nerve injury is a common clinical entity, which may arise due to traumatic, tumorous, or even iatrogenic injury in craniomaxillofacial surgery. Despite advances in biomaterials and techniques over the past several decades, reconstruction of nerve gaps remains a challenge. Autografts are the gold standard for nerve reconstruction. Using autografts, there is donor site morbidity, subsequent sensory deficit, and potential for neuroma development and infection. Moreover, the need for a second surgical site and limited availability of donor nerves remain a challenge. Thus, increasing efforts have been directed to develop artificial nerve guidance conduits (ANCs) as new methods to replace autografts in the future. Various synthetic conduit materials have been tested in vitro and in vivo, and several first- and second-generation conduits are FDA approved and available for purchase, while third-generation conduits still remain in experimental stages. This paper reviews the current treatment options, summarizes the published literature, and assesses future prospects for the repair of peripheral nerve injury in craniomaxillofacial surgery with a particular focus on facial nerve regeneration. Robert Gaudin, Christian Knipfer, Anders Henningsen, Ralf Smeets, Max Heiland, and Tessa Hadlock Copyright © 2016 Robert Gaudin et al. All rights reserved. Long-Term Fatigue and Its Probability of Failure Applied to Dental Implants Tue, 19 Jul 2016 14:23:03 +0000 It is well known that dental implants have a high success rate but even so, there are a lot of factors that can cause dental implants failure. Fatigue is very sensitive to many variables involved in this phenomenon. This paper takes a close look at fatigue analysis and explains a new method to study fatigue from a probabilistic point of view, based on a cumulative damage model and probabilistic finite elements, with the goal of obtaining the expected life and the probability of failure. Two different dental implants were analysed. The model simulated a load of 178 N applied with an angle of 0°, 15°, and 20° and a force of 489 N with the same angles. Von Mises stress distribution was evaluated and once the methodology proposed here was used, the statistic of the fatigue life and the probability cumulative function were obtained. This function allows us to relate each cycle life with its probability of failure. Cylindrical implant has a worst behaviour under the same loading force compared to the conical implant analysed here. Methodology employed in the present study provides very accuracy results because all possible uncertainties have been taken in mind from the beginning. María Prados-Privado, Juan Carlos Prados-Frutos, Sérgio Alexandre Gehrke, Mariano Sánchez Siles, José Luis Calvo Guirado, and José Antonio Bea Copyright © 2016 María Prados-Privado et al. All rights reserved. Non-Mulberry and Mulberry Silk Protein Sericins as Potential Media Supplement for Animal Cell Culture Tue, 19 Jul 2016 11:34:49 +0000 Silk protein sericins, in the recent years, find application in cosmetics and pharmaceuticals and as biomaterials. We investigate the potential of sericin, extracted from both mulberry Bombyx mori and different non-mulberry sources, namely, tropical tasar, Antheraea mylitta; muga, Antheraea assama; and eri, Samia ricini, as growth supplement in serum-free culture medium. Sericin supplemented media containing different concentrations of sericins from the different species are examined for attachment, growth, proliferation, and morphology of fibrosarcoma cells. The optimum sericin supplementation seems to vary with the source of sericins. The results indicate that all the sericins promote the growth of L929 cells in serum-free culture media; however, S. ricini sericin seems to promote better growth of cells amongst other non-mulberry sericins. Neety Sahu, Shilpa Pal, Sunaina Sapru, Joydip Kundu, Sarmistha Talukdar, N. Ibotambi Singh, Juming Yao, and Subhas C. Kundu Copyright © 2016 Neety Sahu et al. All rights reserved. Application of Hydrogel in Reconstruction Surgery: Hydrogel/Fat Graft Complex Filler for Volume Reconstruction in Critical Sized Muscle Defects Thu, 30 Jun 2016 16:08:39 +0000 Autogenic fat graft usually suffers from degeneration and volume shrinkage in volume reconstruction applications. How to maintain graft viability and graft volume is an essential consideration in reconstruction therapies. In this presented investigation, a new fat graft transplantation method was developed aiming to improve long term graft viability and volume reconstruction effect by incorporation of hydrogel. The harvested fat graft is dissociated into small fragments and incorporated into a collagen based hydrogel to form a hydrogel/fat graft complex for volume reconstruction purpose. In vitro results indicate that the collagen based hydrogel can significantly improve the survivability of cells inside isolated graft. In a 6-month investigation on artificial created defect model, this hydrogel/fat graft complex filler has demonstrated the ability of promoting fat pad formation inside the targeted defect area. The newly generated fat pad can cover the whole defect and restore its original dimension in 6-month time point. Compared to simple fat transplantation, this hydrogel/fat graft complex system provides much improvement on long term volume restoration effect against degeneration and volume shrinkage. One notable effect is that there is continuous proliferation of adipose tissue throughout the 6-month period. In summary, the hydrogel/fat graft system presented in this investigation demonstrated a better and more significant effect on volume reconstruction in large sized volume defect than simple fat transplantation. Y. F. Lui and W. Y. Ip Copyright © 2016 Y. F. Lui and W. Y. Ip. All rights reserved. Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Contribute to Chondrogenesis in Coculture with Chondrocytes Thu, 30 Jun 2016 13:56:31 +0000 Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) have been shown as the most potential stem cell source for articular cartilage repair. In this study, we aimed to develop a method for long-term coculture of human articular chondrocytes (hACs) and hUCB-MSCs at low density in vitro to determine if the low density of hACs could enhance the hUCB-MSC chondrogenic differentiation as well as to determine the optimal ratio of the two cell types. Also, we compared the difference between direct coculture and indirect coculture at low density. Monolayer cultures of hUCB-MSCs and hACs were investigated at different ratios, at direct cell-cell contact groups for 21 days. Compared to direct coculture, hUCB-MSCs and hACs indirect contact culture significantly increased type II collagen (COL2) and decreased type I collagen (COL1) protein expression levels. SRY-box 9 (SOX9) mRNA levels and protein expression were highest in indirect coculture. Overall, these results indicate that low density direct coculture induces fibrocartilage. However, indirect coculture in conditioned chondrocyte cell culture medium can increase expression of chondrogenic markers and induce hUCB-MSCs differentiation into mature chondrocytes. This work demonstrates that it is possible to promote chondrogenesis of hUCB-MSCs in combination with hACs, further supporting the concept of novel coculture strategies for tissue engineering. Xingfu Li, Li Duan, Yujie Liang, Weimin Zhu, Jianyi Xiong, and Daping Wang Copyright © 2016 Xingfu Li et al. All rights reserved. Effect of Water-Glass Coating on HA and HA-TCP Samples for MSCs Adhesion, Proliferation, and Differentiation Sun, 26 Jun 2016 12:34:37 +0000 Ca-P and silicon based materials have become very popular as bone tissue engineering materials. In this study, water-glass (also known as sodium silicate glass) was coated on sintered hydroxyapatite (HA) and HA-TCP (TCP stands for tricalcium phosphate) samples and subsequently heat-treated at 600°C for 2 hrs. X-rays diffraction showed the presence of β- and α-TCP phases along with HA in the HA-TCP samples. Samples without coating, with water-glass coating, and heat-treated after water-glass coating were used to observe the adhesion and proliferation response of bone marrow derived-mesenchymal stem cells (MSCs). Cell culture was carried out for 4 hrs, 1 day, and 7 days. Interestingly, all samples showed similar response for cell adhesion and proliferation up to 7-day culture but fibronectin, E-cadherin, and osteogenic differentiation related genes (osteocalcin and osteopontin) were significantly induced in heat-treated water-glass coated HA-TCP samples. A water-glass coating on Ca-P samples was not found to influence the cell proliferation response significantly but activated some extracellular matrix genes and induced osteogenic differentiation in the MSCs. Indu Bajpai, Duk Yeon Kim, Jung Kyong-Jin, In-Hwan Song, and Sukyoung Kim Copyright © 2016 Indu Bajpai et al. All rights reserved. Open-Porous Hydroxyapatite Scaffolds for Three-Dimensional Culture of Human Adult Liver Cells Wed, 15 Jun 2016 12:03:34 +0000 Liver cell culture within three-dimensional structures provides an improved culture system for various applications in basic research, pharmacological screening, and implantable or extracorporeal liver support. Biodegradable calcium-based scaffolds in such systems could enhance liver cell functionality by providing endothelial and hepatic cell support through locally elevated calcium levels, increased surface area for cell attachment, and allowing three-dimensional tissue restructuring. Open-porous hydroxyapatite scaffolds were fabricated and seeded with primary adult human liver cells, which were embedded within or without gels of extracellular matrix protein collagen-1 or hyaluronan. Metabolic functions were assessed after 5, 15, and 28 days. Longer-term cultures exhibited highest cell numbers and liver specific gene expression when cultured on hydroxyapatite scaffolds in collagen-1. Endothelial gene expression was induced in cells cultured on scaffolds without extracellular matrix proteins. Hydroxyapatite induced gene expression for cytokeratin-19 when cells were cultured in collagen-1 gel while culture in hyaluronan increased cytokeratin-19 gene expression independent of the use of scaffold in long-term culture. The implementation of hydroxyapatite composites with extracellular matrices affected liver cell cultures and cell differentiation depending on the type of matrix protein and the presence of a scaffold. The hydroxyapatite scaffolds enable scale-up of hepatic three-dimensional culture models for regenerative medicine applications. Anthony Finoli, Eva Schmelzer, Patrick Over, Ian Nettleship, and Joerg C. Gerlach Copyright © 2016 Anthony Finoli et al. All rights reserved. Development of a Regenerative Peripheral Nerve Interface for Control of a Neuroprosthetic Limb Tue, 17 May 2016 14:20:57 +0000 Background. The purpose of this experiment was to develop a peripheral nerve interface using cultured myoblasts within a scaffold to provide a biologically stable interface while providing signal amplification for neuroprosthetic control and preventing neuroma formation. Methods. A Regenerative Peripheral Nerve Interface (RPNI) composed of a scaffold and cultured myoblasts was implanted on the end of a divided peroneal nerve in rats (). The scaffold material consisted of either silicone mesh, acellular muscle, or acellular muscle with chemically polymerized poly(3,4-ethylenedioxythiophene) conductive polymer. Average implantation time was 93 days. Electrophysiological tests were performed at endpoint to determine RPNI viability and ability to transduce neural signals. Tissue samples were examined using both light microscopy and immunohistochemistry. Results. All implanted RPNIs, regardless of scaffold type, remained viable and displayed robust vascularity. Electromyographic activity and stimulated compound muscle action potentials were successfully recorded from all RPNIs. Physiologic efferent motor action potentials were detected from RPNIs in response to sensory foot stimulation. Histology and transmission electron microscopy revealed mature muscle fibers, axonal regeneration without neuroma formation, neovascularization, and synaptogenesis. Desmin staining confirmed the preservation and maturation of myoblasts within the RPNIs. Conclusions. RPNI demonstrates significant myoblast maturation, innervation, and vascularization without neuroma formation. Melanie G. Urbanchek, Theodore A. Kung, Christopher M. Frost, David C. Martin, Lisa M. Larkin, Adi Wollstein, and Paul S. Cederna Copyright © 2016 Melanie G. Urbanchek et al. All rights reserved. Tissue Engineering in Gene and Cell Therapies for Neurological Disorders Wed, 20 Apr 2016 11:52:41 +0000 Jun Liu, William Z. Suo, Xing-Mei Zhang, Chen Zhang, and Gongxiong Wu Copyright © 2016 Jun Liu et al. All rights reserved. Bone-Healing Capacity of PCL/PLGA/Duck Beak Scaffold in Critical Bone Defects in a Rabbit Model Thu, 03 Mar 2016 07:45:25 +0000 Bone defects are repaired using either natural or synthetic bone grafts. Poly(-caprolactone) (PCL), β-tricalcium phosphate (TCP), and poly(lactic-co-glycolic acid) (PLGA) are widely used as synthetic materials for tissue engineering. This study aimed to investigate the bone-healing capacity of PCL/PLGA/duck beak scaffold in critical bone defects and the oxidative stress status of the graft site in a rabbit model. The in vivo performance of 48 healthy New Zealand White rabbits, weighing between 2.5 and 3.5 kg, was evaluated. The rabbits were assigned to the following groups: group 1 (control), group 2 (PCL/PLGA hybrid scaffolds), group 3 (PCL/PLGA/TCP hybrid scaffolds), and group 4 (PCL/PLGA/DB hybrid scaffolds). A 5 mm critical defect was induced in the diaphysis of the left radius. X-ray, micro-CT, and histological analyses were conducted at (time 0) 4, 8, and 12 weeks after implantation. Furthermore, bone formation markers (bone-specific alkaline phosphatase, carboxyterminal propeptide of type I procollagen, and osteocalcin) were measured and oxidative stress status was determined. X-ray, micro-CT, biochemistry, and histological analyses revealed that the PCL/PLGA/duck beak scaffold promotes new bone formation in rabbit radius by inducing repair, suggesting that it could be a good option for the treatment of fracture. Jae Yeon Lee, Soo Jin Son, Jun Sik Son, Seong Soo Kang, and Seok Hwa Choi Copyright © 2016 Jae Yeon Lee et al. All rights reserved. A Study of Using Massage Therapy Accompanied with Stretching Exercise for Rehabilitation of Mammary Gland Hyperplasia Sun, 28 Feb 2016 08:20:55 +0000 Purpose. To apply massage therapy accompanied with stretching exercises for treatment of mammary gland hyperplasia, evaluate the clinical outcome in patients, and estimate the therapy as a novel treatment method for mammary hyperplasia. Methods. 28 adult female patients were selected and treated with massage therapy and stretching exercises focusing on skeleton muscles of chest, abdomen, and axilla. The mammary gland oxyhemoglobin (OxyHb) and deoxyhemoglobin (DeoxyHb) levels were detected before and after treatment after 15, 30, and 45 days. Results. In this cohort, pretreatment OxyHb (mean ± SD) is (medium-high), and DeoxyHb is (normal). All patients were clinically diagnosed with benign mammary gland hyperplasia and mastitis. The posttreatment OxyHb levels are (normal-medium, 15-day), (normal, 30-day), and (normal, 45-day), and DeoxyHb levels are (normal, 15-day), (normal, 30-day), and (normal, 45-day). Patients were diagnosed with decreased hyperplasia 15 and 30 days after treatment and with no symptom of hyperplasia in mammary gland 45 days after treatment. Conclusion. Mammary gland hyperplasia is closely correlated with pathological changes of skeletal muscles and could be significantly improved by massage therapy and stretching exercises targeting neighboring skeletal muscles. Pin Lv, Yuping Chong, Huagang Zou, and Xiangxian Chen Copyright © 2016 Pin Lv et al. All rights reserved. Clinical Application of Antimicrobial Bone Graft Substitute in Osteomyelitis Treatment: A Systematic Review of Different Bone Graft Substitutes Available in Clinical Treatment of Osteomyelitis Thu, 21 Jan 2016 09:27:09 +0000 Osteomyelitis is a common occurrence in orthopaedic surgery, which is caused by different bacteria. Treatment of osteomyelitis patients aims to eradicate infection by debridement surgery and local and systemic antibiotic therapy. Local treatment increases success rates and can be performed with different antimicrobial bone graft substitutes. This review is performed to assess the level of evidence of synthetic bone graft substitutes in osteomyelitis treatment. According to the PRISMA statement for reporting systematic reviews, different types of clinical studies concerning treatment of osteomyelitis with bone graft substitutes are included. These studies are assessed on their methodological quality as level of evidence and bias and their clinical outcomes as eradication of infection. In the fifteen included studies, the levels of evidence were weak and in ten out of the fifteen studies there was a moderate to high risk of bias. However, first results of the eradication of infection in these studies showed promising results with their relatively high success rates and low complication rates. Due to the low levels of evidence and high risks of bias of the included studies, these results are inconclusive and no conclusions regarding the performed clinical studies of osteomyelitis treatment with antimicrobial bone graft substitutes can be drawn. T. A. G. van Vugt, J. Geurts, and J. J. Arts Copyright © 2016 T. A. G. van Vugt et al. All rights reserved. Cartilage Regeneration in Human with Adipose Tissue-Derived Stem Cells: Current Status in Clinical Implications Wed, 06 Jan 2016 12:37:00 +0000 Osteoarthritis (OA) is one of the most common debilitating disorders among the elderly population. At present, there is no definite cure for the underlying causes of OA. However, adipose tissue-derived stem cells (ADSCs) in the form of stromal vascular fraction (SVF) may offer an alternative at this time. ADSCs are one type of mesenchymal stem cells that have been utilized and have demonstrated an ability to regenerate cartilage. ADSCs have been shown to regenerate cartilage in a variety of animal models also. Non-culture-expanded ADSCs, in the form of SVF along with platelet rich plasma (PRP), have recently been used in humans to treat OA and other cartilage abnormalities. These ADSCs have demonstrated effectiveness without any serious side effects. However, due to regulatory issues, only ADSCs in the form of SVF are currently allowed for clinical uses in humans. Culture-expanded ADSCs, although more convenient, require clinical trials for a regulatory approval prior to uses in clinical settings. Here we present a systematic review of currently available clinical studies involving ADSCs in the form of SVF and in the culture-expanded form, with or without PRP, highlighting the clinical effectiveness and safety in treating OA. Jaewoo Pak, Jung Hun Lee, Wiwi Andralia Kartolo, and Sang Hee Lee Copyright © 2016 Jaewoo Pak et al. All rights reserved. Cross-Sectional Nakagami Images in Passive Stretches Reveal Damage of Injured Muscles Tue, 05 Jan 2016 13:17:11 +0000 Muscle strain is still awanting a noninvasive quantitatively diagnosis tool. High frequency ultrasound (HFU) improves image resolution for monitoring changes of tissue structures, but the biomechanical factors may influence ultrasonography during injury detection. We aim to illustrate the ultrasonic parameters to present the histological damage of overstretched muscle with the consideration of biomechanical factors. Gastrocnemius muscles from mice were assembled and ex vivo passive stretching was performed before or after injury. After injury, the muscle significantly decreased mechanical strength. Ultrasonic images were obtained by HFU at different deformations to scan in cross and longitudinal orientations of muscle. The ultrasonography was quantified by echogenicity and Nakagami parameters (NP) for structural evaluation and correlated with histological results. The injured muscle at its original length exhibited decreased echogenicity and NP from HFU images. Cross-sectional ultrasonography revealed a loss of correlation between NP and passive muscle stretching that suggested a special scatterer pattern in the cross section of injured muscle. The independence of NP during passive stretching of injured muscle was confirmed by histological findings in ruptured collagen fibers, decreased muscle density, and increased intermuscular fiber space. Thus, HFU analysis of NP in cross section represents muscle injury that may benefit the clinical diagnosis. Shih-Ping Lin, Yi-Hsun Lin, Shih-Chen Fan, Bu-Miin Huang, Wei-Yin Lin, Shyh-Hau Wang, K. Kirk Shung, Fong-Chin Su, and Chia-Ching Wu Copyright © 2016 Shih-Ping Lin et al. All rights reserved. Vocal Fold Augmentation with Beta Glucan Hydrogel Cross-Linked by γ Irradiation for Enhanced Duration of Effect: In Vivo Animal Study Sun, 13 Dec 2015 13:51:27 +0000 This study explored a novel strategy to restore the vocal gap by using cross-linked β-glucan hydrogel by γ-irradiation. An aqueous solution of 5 wt% β-glucan was prepared and cross-linked using 60Co γ irradiation. Ten nude mice were injected with 0.8 mL of irradiated β-glucan on the left back and the same volume of nonirradiated β-glucan on the right back for comparison. The mice were sacrificed at 1 and 2 weeks after injection and histological evaluations were performed. Irradiated β-glucan demonstrated a significantly larger volume than nonirradiated β-glucan in the back of nude mice with less inflammatory reaction. After unilateral recurrent laryngeal nerve section in New Zealand White rabbits, irradiated and nonirradiated β-glucan were injected into paralyzed vocal folds. Irradiated β-glucan remained at the paralyzed vocal fold without definite inflammatory signs on endoscopy. High-speed recordings of vocal fold vibration showed decreased vocal gap in irradiated group compared to nonirradiated group. Histologically, the laryngeal epithelium and lamina propria remained intact, without inflammatory cell infiltration. Our newly developed injection material, irradiated β-glucan, showed excellent biocompatibility and remained longer than nonirradiated β-glucan in vivo, suggesting irradiated hydrogels as a new therapeutic approach that may be useful for the long-term treatment of vocal fold palsy. Youn-Mook Lim, Bo Hae Kim, Hee-Bok Kim, EunJi Park, Seok-Won Park, Jong-Seok Park, Se In Choi, Tack-Kyun Kwon, and Seong Keun Kwon Copyright © 2015 Youn-Mook Lim et al. All rights reserved. 3D Culture of MIN-6 Cells on Decellularized Pancreatic Scaffold: In Vitro and In Vivo Study Tue, 24 Nov 2015 12:36:06 +0000 Type 1 diabetes is an autoimmune disease which is due to the lack of β cells. The ideal therapy to cure the disease is pancreas transplantation, but its application is confined to a limited number of people due to the shortage of organ and the need for life-long immunosuppression. Regenerative medicine methods such as a tissue engineered pancreas seem to provide a useful method. In order to construct a microenvironment similar to the native pancreas that is suitable for not only cell growth but also cellular function exertion, a decellularized mouse pancreas was used as a natural 3D scaffold in this experiment. MIN-6 β cells were planted in the bioscaffold. The cell engraftment was verified by HE staining and SEM. Immunostaining procedures were performed to confirm the normal function of the engrafted cells. qRT-PCR demonstrated that insulin gene expression of the recellularized pancreas was upregulated compared with conventional plate-cultured cells. In vivo experiment was also accomplished to further evaluate the function of the recellularized bioscaffold and the result was inspiring. And beyond doubt this will bring new hope for type 1 diabetic patients. Di Wu, Jian Wan, Yan Huang, Yibing Guo, Tianxin Xu, Mingyan Zhu, Xiangjun Fan, Shajun Zhu, Changchun Ling, Xiaohong Li, Jingjing Lu, Hui Zhu, Pengcheng Zhou, Yuhua Lu, and Zhiwei Wang Copyright © 2015 Di Wu et al. All rights reserved. In Vivo Targeted Magnetic Resonance Imaging of Endogenous Neural Stem Cells in the Adult Rodent Brain Sun, 25 Oct 2015 11:40:21 +0000 Neural stem cells in the adult mammalian brain have a significant level of neurogenesis plasticity. In vivo monitoring of adult endogenous NSCs would be of great benefit to the understanding of the neurogenesis plasticity under normal and pathological conditions. Here we show the feasibility of in vivo targeted MR imaging of endogenous NSCs in adult mouse brain by intraventricular delivery of monoclonal anti-CD15 antibody conjugated superparamagnetic iron oxide nanoparticles. After intraventricular administration of these nanoparticles, the subpopulation of NSCs in the anterior subventricular zone and the beginning of the rostral migratory stream could be in situ labeled and were in vivo visualized with 7.0-T MR imaging during a period from 1 day to 7 days after the injection. Histology confirmed that the injected targeted nanoparticles were specifically bound to CD15 positive cells and their surrounding extracellular matrix. Our results suggest that in vivo targeted MR imaging of endogenous neural stem cells in adult rodent brain could be achieved by using anti-CD15-SPIONs as the molecular probe; and this targeting imaging strategy has the advantage of a rapid in vivo monitoring of the subpopulation of endogenous NSCs in adult brains. Xiao-Mei Zhong, Fang Zhang, Ming Yang, Xue-Hua Wen, Xiang Zhang, Xiao-Hui Duan, and Jun Shen Copyright © 2015 Xiao-Mei Zhong et al. All rights reserved. Calreticulin Binds to Fas Ligand and Inhibits Neuronal Cell Apoptosis Induced by Ischemia-Reperfusion Injury Sun, 25 Oct 2015 11:30:36 +0000 Background. Calreticulin (CRT) can bind to Fas ligand (FasL) and inhibit Fas/FasL-mediated apoptosis of Jurkat T cells. However, its effect on neuronal cell apoptosis has not been investigated. Purpose. We aimed to evaluate the neuroprotective effect of CRT following ischemia-reperfusion injury (IRI). Methods. Mice underwent middle cerebral artery occlusion (MCAO) and SH-SY5Y cells subjected to oxygen glucose deprivation (OGD) were used as models for IRI. The CRT protein level was detected by Western blotting, and mRNA expression of CRT, caspase-3, and caspase-8 was measured by real-time PCR. Immunofluorescence was used to assess the localization of CRT and FasL. The interaction of CRT with FasL was verified by coimmunoprecipitation. SH-SY5Y cell viability was determined by MTT assay, and cell apoptosis was assessed by flow cytometry. The measurement of caspase-8 and caspase-3 activity was carried out using caspase activity assay kits. Results. After IRI, CRT was upregulated on the neuron surface and bound to FasL, leading to increased viability of OGD-exposed SH-SY5Y cells and decreased activity of caspase-8 and caspase-3. Conclusions. This study for the first time revealed that increased CRT inhibited Fas/FasL-mediated neuronal cell apoptosis during the early stage of ischemic stroke, suggesting it to be a potential protector activated soon after IRI. Beilei Chen, Zhengzheng Wu, Jun Xu, and Yun Xu Copyright © 2015 Beilei Chen et al. All rights reserved. Effects of Nogo-A Silencing on TNF-α and IL-6 Secretion and TH Downregulation in Lipopolysaccharide-Stimulated PC12 Cells Sun, 25 Oct 2015 11:19:32 +0000 Parkinson’s disease (PD) is a common degenerative disease that lacks efficient treatment. Myelin-associated neurite outgrowth inhibitor A (Nogo-A) is relevant with inhibition of nerve regeneration and may play vital role in pathogenesis of PD. The study aimed to establish the shRNA expression plasmids of Nogo-A gene and explore the regulatory effects of Nogo-A silencing on the expression of inflammation factor tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) as well as tyrosine hydroxylase (TH) in lipopolysaccharide- (LPS-) stimulated rat PC12 cells. The results showed that both mRNA and protein levels of Nogo-A in pGenesil-nogoA-shRNA group were downregulated. The viabilities of PC12 cells decreased with increase of LPS concentrations. LPS significantly increased the supernatant TNF-alpha and IL-6 concentrations and reduced TH protein expression in PC12 cells, while silencing Nogo-A could block these effects. These results suggested that LPS can activate PC12 cells to secrete inflammatory cytokines and lower the TH expression, which can be regulated by Nogo-A gene silencing. Nogo-A silencing might provide new ideas for PD treatment in the future. Jianbin Zhong, Shengnuo Fan, Zhenwen Yan, Songhua Xiao, Limei Wan, Chibang Chen, Simin Zhong, Lu Liu, and Jun Liu Copyright © 2015 Jianbin Zhong et al. All rights reserved. Screening and Identification of ssDNA Aptamer for Human GP73 Sun, 25 Oct 2015 11:06:30 +0000 As one tumor marker of HCC, Golgi Protein 73 (GP73) is given more promise in the early diagnosis of HCC, and aptamers have been developed to compete with antibodies as biorecognition probes in different detection system. In this study, we utilized GP73 to screen specific ssDNA aptamers by SELEX technique. First, GP73 proteins were expressed and purified by prokaryotic expression system and Nickle ion affinity chromatography, respectively. At the same time, the immunogenicity of purified GP73 was confirmed by Western blotting. The enriched ssDNA library with high binding capacity for GP73 was obtained after ten rounds of SELEX. Then, thirty ssDNA aptamers were sequenced, in which two ssDNA aptamers with identical DNA sequence were confirmed, based on the alignment results, and designated as A10-2. Furthermore, the specific antibody could block the binding of A10-2 to GP73, and the specific binding of A10-2 to GP73 was also supported by the observation that several tumor cell lines exhibited variable expression level of GP73. Significantly, the identified aptamer A10-2 could distinguish normal and cancerous liver tissues. So, our results indicate that the aptamer A10-2 might be developed into one molecular probe to detect HCC from normal liver specimens. Jingchun Du, Jianming Hong, Chun Xu, Yuanyuan Cai, Bo Xiang, Chengbo Zhou, and Xia Xu Copyright © 2015 Jingchun Du et al. All rights reserved. PI3K/AKT/mTOR/p70S6K Pathway Is Involved in Aβ25-35-Induced Autophagy Sun, 25 Oct 2015 09:08:14 +0000 Disruption or deregulation of the autophagy system has been implicated in neurodegenerative disorders such as Alzheimer’s disease (AD). Aβ plays an important role in this autophagic system. In many cases, autophagy is regulated by the phosphatidylinositol 3-phosphate kinase/AKT/mammalian target of rapamycin/p70 ribosomal protein S6 kinase (PI3K/AKT/mTOR/p70S6K) signaling pathway. However, whether this signaling pathway is involved in Aβ-induced autophagy in neuronal cells is not known. Here, we studied whether Aβ25-35 induces autophagy in HT22 cells and C57 mice and investigated whether PI3K is involved in the autophagy induction. We found that Aβ25-35 inhibited HT22 cell viability in a dose- and time-dependent manner. Aβ25-35 induced autophagosome formation, the conversion of microtubule-associated protein light chain 3 (LC3), and the suppression of the mTOR pathway both in vitro and in vivo. Furthermore, Aβ25-35 impaired the learning abilities of C57 mice. Our study suggests that Aβ25-35 induces autophagy and the PI3K/AKT/mTOR/p70S6K pathway is involved in the process, which improves our understanding of the pathogenesis of AD and provides an additional model for AD research. Shengnuo Fan, Bei Zhang, Ping Luan, Beibei Gu, Qing Wan, Xiaoyun Huang, Wang Liao, and Jun Liu Copyright © 2015 Shengnuo Fan et al. All rights reserved. Overexpression of NTRK1 Promotes Differentiation of Neural Stem Cells into Cholinergic Neurons Mon, 05 Oct 2015 14:23:05 +0000 Neurotrophic tyrosine kinase type 1 (NTRK1) plays critical roles in proliferation, differentiation, and survival of cholinergic neurons; however, it remains unknown whether enhanced expression of NTRK1 in neural stem cells (NSCs) can promote their differentiation into mature neurons. In this study, a plasmid encoding the rat NTRK1 gene was constructed and transfected into C17.2 mouse neural stem cells (NSCs). NTRK1 overexpression in C17.2 cells was confirmed by western blot. The NSCs overexpressing NTRK1 and the C17.2 NSCs transfected by an empty plasmid vector were treated with or without 100 ng/mL nerve growth factor (NGF) for 7 days. Expression of the cholinergic cell marker, choline acetyltransferase (ChAT), was detected by florescent immunocytochemistry (ICC). In the presence of NGF induction, the NSCs overexpressing NTRK1 differentiated into ChAT-immunopositive cells at 3-fold higher than the NSCs transfected by the plasmid vector (26% versus 9%, ). The data suggest that elevated NTRK1 expression increases differentiation of NSCs into cholinergic neurons under stimulation of NGF. The approach also represents an efficient strategy for generation of cholinergic neurons. Limin Wang, Feng He, Zhuoyuan Zhong, Ruiyan Lv, Songhua Xiao, and Zhonglin Liu Copyright © 2015 Limin Wang et al. All rights reserved. Bone and Tooth Regeneration in Maxillofacial Region Mon, 28 Sep 2015 12:06:22 +0000 Kazuhisa Bessho, Joo L. Ong, Norbert R. Kübler, and John G. Clement Copyright © 2015 Kazuhisa Bessho et al. All rights reserved. Amniotic Mesenchymal Stem Cells Can Enhance Angiogenic Capacity via MMPs In Vitro and In Vivo Sun, 27 Sep 2015 12:52:22 +0000 The aim of this study was to evaluate the angiogenic capacity and proteolytic mechanism of coculture using human amniotic mesenchymal stem cells (hAMSCs) with human umbilical vein endothelial cells (HUVECs) in vivo and in vitro by comparing to those of coculture using bone marrow mesenchymal stem cells with HUVEC. For the in vivo experiment, cells (HUVEC-monoculture, HUVEC-hAMSC coculture, and HUVEC-BMMSC coculture) were seeded in fibrin gels and injected subcutaneously in nude mice. The samples were collected on days 7 and 14 and histologically analyzed by H&E and CD31 staining. CD31-positive staining percentage and vessel-like structure (VLS) density were evaluated as quantitative parameters for angiogenesis. The increases of CD31-positive staining area and VLS density in both HUVEC-hAMSC group and HUVEC-BMMSC group were found between two time points, while obvious decline of those was observed in HUVEC-only group. For the in vitro experiment, we utilized the same 3D culture model to investigate the proteolytic mechanism related to capillary formation. Intensive vascular networks formed by HUVECs were associated with hAMSCs or BMMSCs and related to MMP2 and MMP9. In conclusion, hAMSCs shared similar capacity and proteolytic mechanism with BMMSCs on neovascularization. Fei Jiang, Jie Ma, Yi Liang, Yuming Niu, Ning Chen, and Ming Shen Copyright © 2015 Fei Jiang et al. All rights reserved. Endothelial Progenitor Cell Fraction Contained in Bone Marrow-Derived Mesenchymal Stem Cell Populations Impairs Osteogenic Differentiation Sun, 27 Sep 2015 12:34:55 +0000 In bone tissue engineering (TE) endothelial cell-osteoblast cocultures are known to induce synergies of cell differentiation and activity. Bone marrow mononucleated cells (BMCs) are a rich source of mesenchymal stem cells (MSCs) able to develop an osteogenic phenotype. Endothelial progenitor cells (EPCs) are also present within BMC. In this study we investigate the effect of EPCs present in the BMC population on MSCs osteogenic differentiation. Human BMCs were isolated and separated into two populations. The MSC population was selected through plastic adhesion capacity. EPCs (CD34+ and CD133+) were removed from the BMC population and the resulting population was named depleted MSCs. Both populations were cultured over 28 days in osteogenic medium (Dex+) or medium containing platelet lysate (PL). MSC population grew faster than depleted MSCs in both media, and PL containing medium accelerated the proliferation for both populations. Cell differentiation was much higher in Dex+ medium in both cases. Real-time RT-PCR revealed upregulation of osteogenic marker genes in depleted MSCs. Higher values of ALP activity and matrix mineralization analyses confirmed these results. Our study advocates that absence of EPCs in the MSC population enables higher osteogenic gene expression and matrix mineralization and therefore may lead to advanced bone neoformation necessary for TE constructs. Fabian Duttenhoefer, Rafael Lara de Freitas, Markus Loibl, Gido Bittermann, R. Geoff Richards, Mauro Alini, and Sophie Verrier Copyright © 2015 Fabian Duttenhoefer et al. All rights reserved. Are Biodegradable Osteosyntheses Still an Option for Midface Trauma? Longitudinal Evaluation of Three Different PLA-Based Materials Sun, 27 Sep 2015 12:32:52 +0000 The aim was to evaluate three different biodegradable polylactic acid- (PLA-) based osteosynthesis materials (OM). These OM (BioSorb, LactoSorb, and Delta) were used in 64 patients of whom 55 (85.9%) had fractures of the zygoma, five (7.8%) in the LeFort II level, two of the frontal bone (3.1%), and two of the maxillary sinus wall (3.1%). In addition to routine follow-up (FU) at 3, 6, and 12 months (m) (T1, T2, and T3) all patients were finally evaluated at a mean FU after 14.1 m for minor (e.g., nerve disturbances, swelling, and pain) and major (e.g., infections and occlusal disturbances) complications. Out of all 64 patients 38 presented with complications; of these 28 were minor (43.8%) and 10 major (15.6%) resulting in an overall rate of 59.4%. Differences in minor complications regarding sensibility disturbance at T1 and T3 were statistically significant (). Differences between the OM were not statistically significant. Apart from sufficient mechanical stability for clinical use of all tested OM complications mostly involved pain and swelling probably mainly related to the initial bulk reaction attributable to the drop of pH value during the degradation process. This paper includes a review of the current aspects of biodegradable OM. Andreas Kolk, Robert Köhnke, Christoph H. Saely, and Oliver Ploder Copyright © 2015 Andreas Kolk et al. All rights reserved. Biocompatibility of Novel Type I Collagen Purified from Tilapia Fish Scale: An In Vitro Comparative Study Sun, 27 Sep 2015 12:03:46 +0000 Type I collagen (COL-1) is the prevailing component of the extracellular matrix in a number of tissues including skin, ligament, cartilage, bone, and dentin. It is the most widely used tissue-derived natural polymer. Currently, mammalian animals, including pig, cow, and rat, are the three major sources for purification of COL-1. To reduce the risk of zoonotic infectious diseases transmission, minimize the possibility of immunogenic reaction, and avoid problems related to religious issues, exploration of new sources (other than mammalian animals) for the purification of type I collagen is highly desirable. Hence, the purpose of the current study was to investigate the in vitro responses of MDPC-23 to type I collagen isolated from tilapia scale in terms of cellular proliferation, differentiation, and mineralization. The results suggested that tilapia scale collagen exhibited comparable biocompatibility to porcine skin collagen, indicating it might be a potential alternative to type I collagen from mammals in the application for tissue regeneration in oral-maxillofacial area. Jia Tang and Takashi Saito Copyright © 2015 Jia Tang and Takashi Saito. All rights reserved. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole Sun, 27 Sep 2015 10:57:26 +0000 Recently a submicron particle of biphasic calcium phosphate ceramic (BCP) with through-hole (donut-shaped BCP (d-BCP)) was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing. Byung-Chul Jeong, Hyuck Choi, Sung-Woong Hur, Jung-Woo Kim, Sin-Hye Oh, Hyun-Seung Kim, Soo-Chang Song, Keun-Bae Lee, Kwang-Bum Park, and Jeong-Tae Koh Copyright © 2015 Byung-Chul Jeong et al. All rights reserved. Potentiated Osteoinductivity via Cotransfection with BMP-2 and VEGF Genes in Microencapsulated C2C12 Cells Wed, 16 Sep 2015 13:32:08 +0000 Microcapsules with entrapped cells hold great promise for repairing bone defects. Unfortunately, the osteoinductivity of microcapsules has been restricted by many factors, among which the deficiency of functional proteins is a significant priority. We potentiated the osteoinductivity of microencapsulated cells via cotransfection with BMP-2 and VEGF genes. Various tissue-derived mesenchymal stem cells and cell lines were compared for BMP-2 and VEGF cotransfection. Ethidium bromide (EB)/Calcein AM staining revealed that all of the cell categories could survive for 4 weeks after microencapsulation. An ELISA assay indicated that all microencapsulated BMP-2 or VEGF transfected cells could secrete gene products constitutively for 1 month. Particularly, the recombinant microencapsulated C2C12 cells released the most desirable level of BMP-2 and VEGF. Further experiments demonstrated that microencapsulated BMP-2 and VEGF cotransfected C2C12 cells generated both BMP-2 and VEGF for 4 weeks. Additionally, the cotransfection of BMP-2 and VEGF in microencapsulated C2C12 cells showed a stronger osteogenic induction against BMSCs than individual BMP-2-transfected microencapsulated C2C12 cells. These results demonstrated that the cotransfection of BMP-2 and VEGF into microencapsulated C2C12 cells is of potent utility for the potentiation of bone regeneration, which would provide a promising clinical strategy for cellular therapy in bone defects. Yang Shen, Han Qiao, Qiming Fan, Shuhong Zhang, and Tingting Tang Copyright © 2015 Yang Shen et al. All rights reserved. Comprehensive Review of Adipose Stem Cells and Their Implication in Distraction Osteogenesis and Bone Regeneration Sun, 13 Sep 2015 14:04:05 +0000 Bone is one of the most dynamic tissues in the human body that can heal following injury without leaving a scar. However, in instances of extensive bone loss, this intrinsic capacity of bone to heal may not be sufficient and external intervention becomes necessary. Several techniques are available to address this problem, including autogenous bone grafts and allografts. However, all these techniques have their own limitations. An alternative method is the technique of distraction osteogenesis, where gradual and controlled distraction of two bony segments after osteotomy leads to induction of new bone formation. Although distraction osteogenesis usually gives satisfactory results, its major limitation is the prolonged duration of time required before the external fixator is removed, which may lead to numerous complications. Numerous methods to accelerate bone formation in the context of distraction osteogenesis have been reported. A viable alternative to autogenous bone grafts for a source of osteogenic cells is mesenchymal stem cells from bone marrow. However, there are certain problems with bone marrow aspirate. Hence, scientists have investigated other sources for mesenchymal stem cells, specifically adipose tissue, which has been shown to be an excellent source of mesenchymal stem cells. In this paper, the potential use of adipose stem cells to stimulate bone formation is discussed. Mina W. Morcos, Hadil Al-Jallad, and Reggie Hamdy Copyright © 2015 Mina W. Morcos et al. All rights reserved. The Effects of TiO2 Nanodot Films with RGD Immobilization on Light-Induced Cell Sheet Technology Mon, 31 Aug 2015 06:10:21 +0000 Cell sheet technology is a new strategy in tissue engineering which could be possible to implant into the body without a scaffold. In order to get an integrated cell sheet, a light-induced method via UV365 is used for cell sheet detachment from culture dishes. In this study, we investigated the possibility of cell detachment and growth efficiency on TiO2 nanodot films with RGD immobilization on light-induced cell sheet technology. Mouse calvaria-derived, preosteoblastic (MC3T3-E1) cells were cultured on TiO2 nanodot films with (TR) or without (TN) RGD immobilization. After cells were cultured with or without 5.5 mW/cm2 UV365 illumination, cell morphology, cell viability, osteogenesis related RNA and protein expression, and cell detachment ability were compared, respectively. Light-induced cell detachment was possible when cells were cultured on TR samples. Also, cells cultured on TR samples showed better cell viability, alongside higher protein and RNA expression than on TN samples. This study provides a new biomaterial for light-induced cell/cell sheet harvesting. Meng-Liu Yu, Meng-Fei Yu, Li-Qin Zhu, Tian-Tian Wang, Yi Zhou, and Hui-Ming Wang Copyright © 2015 Meng-Liu Yu et al. All rights reserved. Probiotics (Bifidobacterium longum) Increase Bone Mass Density and Upregulate Sparc and Bmp-2 Genes in Rats with Bone Loss Resulting from Ovariectomy Thu, 20 Aug 2015 13:09:50 +0000 Probiotics are live microorganisms that exert beneficial effects on the host, when administered in adequate amounts. Mostly, probiotics affect the gastrointestinal (GI) tract of the host and alter the composition of gut microbiota. Nowadays, the incidence of hip fractures due to osteoporosis is increasing worldwide. Ovariectomized (OVX) rats have fragile bone due to estrogen deficiency and mimic the menopausal conditions in women. Therefore, this study aimed to examine the effects of Bifidobacterium longum (B. longum) on bone mass density (BMD), bone mineral content (BMC), bone remodeling, bone structure, and gene expression in OVX rats. The rats were randomly assigned into 3 groups (sham, OVX, and the OVX group supplemented with 1 mL of B. longum 108–109 colony forming units (CFU)/mL). B. longum was given once daily for 16 weeks, starting from 2 weeks after the surgery. The B. longum supplementation increased () serum osteocalcin (OC) and osteoblasts, bone formation parameters, and decreased serum C-terminal telopeptide (CTX) and osteoclasts, bone resorption parameters. It also altered the microstructure of the femur. Consequently, it increased BMD by increasing () the expression of Sparc and Bmp-2 genes. B. longum alleviated bone loss in OVX rats and enhanced BMD by decreasing bone resorption and increasing bone formation. Kolsoom Parvaneh, Mahdi Ebrahimi, Mohd Redzwan Sabran, Golgis Karimi, Angela Ng Min Hwei, Saif Abdul-Majeed, Zuraini Ahmad, Zuriati Ibrahim, and Rosita Jamaluddin Copyright © 2015 Kolsoom Parvaneh et al. All rights reserved. The Effect of Bone Marrow-Derived Mesenchymal Stem Cells and Their Conditioned Media Topically Delivered in Fibrin Glue on Chronic Wound Healing in Rats Tue, 07 Jul 2015 12:15:36 +0000 Bone marrow-derived mesenchymal stem cells (BM-MSCs) represent a modern approach for management of chronic skin injuries. In this work, we describe BM-MSCs application versus their conditioned media (CM) when delivered topically admixed with fibrin glue to enhance the healing of chronic excisional wounds in rats. Fifty-two adult male rats were classified into four groups after induction of large-sized full-thickness skin wound: control group (CG), fibrin only group (FG), fibrin + MSCs group (FG + SCs), and fibrin + CM group (FG + CM). Healing wounds were evaluated functionally and microscopically. Eight days after injury, number of CD68+ macrophages infiltrating granulation tissue was considerably higher in the latter two groups. Although—later—none of the groups depicted a substantially different healing rate, the quality of regenerated skin was significantly boosted by the application of either BM-MSCs or their CM both (1) structurally as demonstrated by the obviously increased mean area percent of collagen fibers in Masson’s trichrome-stained skin biopsies and (2) functionally as supported by the interestingly improved epidermal barrier as well as dermal tensile strength. Thus, we conclude that topically applied BM-MSCs and their CM—via fibrin vehicle—could effectively improve the quality of healed skin in chronic excisional wounds in rats, albeit without true acceleration of wound closure. Radwa A. Mehanna, Iman Nabil, Noha Attia, Amany A. Bary, Khalid A. Razek, Tamer A. E. Ahmed, and Fatma Elsayed Copyright © 2015 Radwa A. Mehanna et al. All rights reserved. Synthesis and Properties of Flexible Polyurethane Using Ferric Catalyst for Hypopharyngeal Tissue Engineering Mon, 06 Jul 2015 09:52:08 +0000 Biodegradable polyurethane is an ideal candidate material to fabricate tissue engineered hypopharynx from its good mechanical properties and biodegradability. We thus synthesized a hydrophilic polyurethane via reactions among polyethylene glycol (PEG), e-caprolactone (e-CL) and hexamethylene diisocyanate (HDI), and thrihydroxymethyl propane (TMP). The product possessed a fast degradability due to its good wettability and good mechanical parameters with the elongations at break (137 ± 10%) and tensile strength (4.73 ± 0.46 MPa), which will make it a good matrix material for soft tissue like hypopharynx. Its biological properties were evaluated via in vitro and in vivo tests. The results showed that this hydrophilic polyurethane material can support hypopharyngeal fibroblast growth and owned good degradability and low inflammatory reaction in subcutaneous implantation. It will be proposed as the scaffold for hypopharyngeal tissue engineering research in our future study. Zhisen Shen, Jian Wang, Dakai Lu, Qun Li, Chongchang Zhou, Yabin Zhu, and Xiao Hu Copyright © 2015 Zhisen Shen et al. All rights reserved. Cyclic Tensile Strain Induces Tenogenic Differentiation of Tendon-Derived Stem Cells in Bioreactor Culture Wed, 01 Jul 2015 10:54:40 +0000 Different loading regimens of cyclic tensile strain impose different effects on cell proliferation and tenogenic differentiation of TDSCs in three-dimensional (3D) culture in vitro, which has been little reported in previous literatures. In this study we assessed the efficacy of TDSCs in a poly(L-lactide-co-ε-caprolactone)/collagen (P(LLA-CL)/Col) scaffold under mechanical stimulation in the custom-designed 3D tensile bioreactor, which revealed that cyclic tensile strain with different frequencies (0.3 Hz, 0.5 Hz, and 1.0 Hz) and amplitudes (2%, 4%, and 8%) had no influence on TDSC viability, while it had different effects on the proliferation and the expression of type I collagen, tenascin-C, tenomodulin, and scleraxis of TDSCs, which was most obvious at 0.5 Hz frequency with the same amplitude and at 4% amplitude with the same frequency. Moreover, signaling pathway from microarray analysis revealed that reduced extracellular matrix (ECM) receptor interaction signaling initiated the tendon genius switch. Cyclic tensile strain highly upregulated genes encoding regulators of NPM1 and COPS5 transcriptional activities as well as MYC related transcriptional factors, which contributed to cell proliferation and differentiation. In particular, the transcriptome analysis provided certain new insights on the molecular and signaling networks for TDSCs loaded in these conditions. Yuan Xu, Qiang Wang, Yudong Li, Yibo Gan, Pei Li, Songtao Li, Yue Zhou, and Qiang Zhou Copyright © 2015 Yuan Xu et al. All rights reserved. Immunomodulatory Role of Adipose-Derived Stem Cells on Equine Endometriosis Tue, 09 Jun 2015 16:07:18 +0000 Endometriosis is a degenerative process due to a chronic inflammatory damage leading to extracellular matrix components deposition and glandular fibrosis. It is known that mesenchymal stem cells secrete a wide range of bioactive molecules, some of them modulating the immune inflammatory response, and others providing regeneration and remodeling of injured tissue. We have performed in vitro experiments in order to analyze the capability of allogenic equine adipose-derived stem cells (ADSCs) to infiltrate mares’ endometrial tissues and to stimulate the expression of cytokines and metallopeptidases. Differences in the biologic response to the exposure to ADSCs between pathological and healthy endometrial tissue have been identified. These results could challenge researchers to progress forward with future studies for the development of a biological therapy with a possible application in translational medicine. Maria Elena Falomo, Letizia Ferroni, Ilaria Tocco, Chiara Gardin, and Barbara Zavan Copyright © 2015 Maria Elena Falomo et al. All rights reserved. Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells into Insulin-Producing Cells: Evidence for Further Maturation In Vivo Tue, 12 May 2015 11:29:24 +0000 The aim of this study was to provide evidence for further in vivo maturation of insulin-producing cells (IPCs) derived from human bone marrow-derived mesenchymal stem cells (HBM-MSCs). HBM-MSCs were obtained from three insulin-dependent type 2 diabetic volunteers. Following expansion, cells were differentiated according to a trichostatin-A/GLP protocol. One million cells were transplanted under the renal capsule of 29 diabetic nude mice. Blood glucose, serum human insulin and c-peptide levels, and glucose tolerance curves were determined. Mice were euthanized 1, 2, 4, or 12 weeks after transplantation. IPC-bearing kidneys were immunolabeled, number of IPCs was counted, and expression of relevant genes was determined. At the end of in vitro differentiation, all pancreatic endocrine genes were expressed, albeit at very low values. The percentage of IPCs among transplanted cells was small (≤3%). Diabetic animals became euglycemic days after transplantation. Thereafter, the percentage of IPCs reached a mean of ~18% at 4 weeks. Relative gene expression of insulin, glucagon, and somatostatin showed a parallel increase. The ability of the transplanted cells to induce euglycemia was due to their further maturation in the favorable in vivo microenvironment. Elucidation of the exact mechanism(s) involved requires further investigation. Mahmoud M. Gabr, Mahmoud M. Zakaria, Ayman F. Refaie, Sherry M. Khater, Sylvia A. Ashamallah, Amani M. Ismail, Sawsan M. El-Halawani, and Mohamed A. Ghoneim Copyright © 2015 Mahmoud M. Gabr et al. All rights reserved. Osteogenic Matrix Cell Sheets Facilitate Osteogenesis in Irradiated Rat Bone Tue, 12 May 2015 08:23:58 +0000 Reconstruction of large bone defects after resection of malignant musculoskeletal tumors is a significant challenge in orthopedic surgery. Extracorporeal autogenous irradiated bone grafting is a treatment option for bone reconstruction. However, nonunion often occurs because the osteogenic capacity is lost by irradiation. In the present study, we established an autogenous irradiated bone graft model in the rat femur to assess whether osteogenic matrix cell sheets improve osteogenesis of the irradiated bone. Osteogenic matrix cell sheets were prepared from bone marrow-derived stromal cells and co-transplanted with irradiated bone. X-ray images at 4 weeks after transplantation showed bridging callus formation around the irradiated bone. Micro-computed tomography images at 12 weeks postoperatively showed abundant callus formation in the whole circumference of the irradiated bone. Histology showed bone union between the irradiated bone and host femur. Mechanical testing showed that the failure force at the irradiated bone site was significantly higher than in the control group. Our study indicates that osteogenic matrix cell sheet transplantation might be a powerful method to facilitate osteogenesis in irradiated bones, which may become a treatment option for reconstruction of bone defects after resection of malignant musculoskeletal tumors. Yoshinobu Uchihara, Manabu Akahane, Takamasa Shimizu, Tomoyuki Ueha, Yusuke Morita, Shintaro Nakasaki, Tomohiko Kura, Yasuaki Tohma, Akira Kido, Kenji Kawate, and Yasuhito Tanaka Copyright © 2015 Yoshinobu Uchihara et al. All rights reserved. The Role of Microvesicles Derived from Mesenchymal Stem Cells in Lung Diseases Tue, 12 May 2015 06:28:08 +0000 Microvesicles (MVs) are membrane vesicles that are released by many types of cells and have recently been considered important mediators of cell-to-cell communication. MVs serve as a vehicle to transfer proteins and messenger RNA and microRNA (miRNA) to distant cells, which alters the gene expression, proliferation, and differentiation of the recipient cells. Several studies have demonstrated that mesenchymal stem cells (MSCs) have the capacity to reverse acute and chronic lung injury in different experimental models through paracrine mechanisms. This paracrine action may be partially accounted for by MVs that are derived from MSCs. MSC-derived MVs may confer a stem cell-like phenotype to injured cells with the consequent activation of self-regenerative programmers. In this review, we summarize the characteristics and biological activities of MSC-derived MVs, and we describe their potential in novel therapeutic approaches in regenerative medicine to repair damaged tissues. Additionally, we provide an overview of studies that have assessed the role of MSC-derived MVs in lung diseases, including the mechanisms that may account for their therapeutic potential. Finally, we discuss the clinical use of MSC-derived MVs with several suggestions for enhancing their therapeutic efficiency. Jie Chen, Chonghui Li, and Liangan Chen Copyright © 2015 Jie Chen et al. All rights reserved. Comment on “Microsurgical Techniques Used to Construct the Vascularized and Neurotized Tissue Engineered Bone” Wed, 06 May 2015 12:04:46 +0000 Annika Weigand, Justus P. Beier, Andreas Arkudas, Raymund E. Horch, and Anja M. Boos Copyright © 2015 Annika Weigand et al. All rights reserved. Mechanical Strain Regulates Osteogenic and Adipogenic Differentiation of Bone Marrow Mesenchymal Stem Cells Thu, 02 Apr 2015 11:28:56 +0000 This study examined the effects of mechanical strain on osteogenic and adipogenic differentiation of cultured MSCs by stimulating MSCs cultured in general and adipogenic differentiation media using a mechanical strain device. Markers of osteogenic (Runx2, Osx, and I-collagen) and adipogenic (PPARγ-2, C/EBPα, and lipid droplets) differentiation were examined using real-time PCR, western blot, immunocytochemical, or histochemical stain analyses. Levels of Runx2 and Osx gradually increased in MSC groups in general medium subject to strain stimulation, as compared with in unstrained groups. After adding the stress signal, I-collagen protein levels of expression were obviously promoted in cells in comparison to the controls. The levels of PPARγ-2 and C/EBPα were decreased, and the emergence of lipid droplets was delayed in MSCs groups in adipogenic differentiation medium subject to strain stimulation, as compared with in unstrained groups. Mechanical strain can promote differentiation of MSCs into osteoblasts and can impede differentiation into adipocytes. These results clarify the mechanisms underlying the effects of exercise on bone repair and reconstruction and provide a more adequate scientific basis for the use of exercise therapy in the treatment of obesity and metabolic osteoporosis. Runguang Li, Liang Liang, Yonggang Dou, Zeping Huang, Huiting Mo, Yaning Wang, and Bin Yu Copyright © 2015 Runguang Li et al. All rights reserved. Design, Materials, and Mechanobiology of Biodegradable Scaffolds for Bone Tissue Engineering Thu, 26 Mar 2015 07:27:29 +0000 A review about design, manufacture, and mechanobiology of biodegradable scaffolds for bone tissue engineering is given. First, fundamental aspects about bone tissue engineering and considerations related to scaffold design are established. Second, issues related to scaffold biomaterials and manufacturing processes are discussed. Finally, mechanobiology of bone tissue and computational models developed for simulating how bone healing occurs inside a scaffold are described. Marco A. Velasco, Carlos A. Narváez-Tovar, and Diego A. Garzón-Alvarado Copyright © 2015 Marco A. Velasco et al. All rights reserved. The Rapid Inactivation of Porcine Skin by Applying High Hydrostatic Pressure without Damaging the Extracellular Matrix Tue, 24 Mar 2015 14:13:21 +0000 We previously reported that high hydrostatic pressure (HHP) of 200 MPa for 10 minutes could induce cell killing. In this study, we explored whether HHP at 200 MPa or HHP at lower pressure, in combination with hyposmotic distilled water (DW), could inactivate the skin, as well as cultured cells. We investigated the inactivation of porcine skin samples 4 mm in diameter. They were immersed in either a normal saline solution (NSS) or DW, and then were pressurized at 100 and 200 MPa for 5, 10, 30, or 60 min. Next, we explored the inactivation of specimens punched out from the pressurized skin 10 × 2 cm in size. The viability was evaluated using a WST-8 assay and an outgrowth culture. The histology of specimens was analyzed histologically. The mitochondrial activity was inactivated after the pressurization at 200 MPa in both experiments, and no outgrowth was observed after the pressurization at 200 MPa. The arrangement and proportion of the dermal collagen fibers or the elastin fibers were not adversely affected after the pressurization at 200 MPa for up to 60 minutes. This study showed that a HHP at 200 MPa for 10 min could inactivate the skin without damaging the dermal matrix. Naoki Morimoto, Atsushi Mahara, Kouji Shima, Mami Ogawa, Chizuru Jinno, Natsuko Kakudo, Kenji Kusumoto, Toshia Fujisato, Shigehiko Suzuki, and Tetsuji Yamaoka Copyright © 2015 Naoki Morimoto et al. All rights reserved. mir-21 Overexpressing Mesenchymal Stem Cells Accelerate Fracture Healing in a Rat Closed Femur Fracture Model Mon, 23 Mar 2015 08:49:49 +0000 MicroRNAs are small noncoding RNAs involved in numerous biological processes. Emerging pieces of evidence suggest that microRNAs play important roles in osteogenesis and skeletal homeostasis. Recent studies indicated the significant regulation function of mir-21 in osteogenesis in vitro, but little information is known about its veritable functions in vivo. In the present study, we aimed to investigate the effect of mir-21 intervention on osteogenic differentiation of rats bone marrow derived mesenchymal stem cells (rBMSCs) and repair capacity in rats closed femur fracture model with internal fixation. The results showed that the upregulation of mir-21 not only increased the expression of osteopontin and alkaline phosphatase in rBMSCs but also promoted mineralization in the condition of osteogenic induction. Furthermore, the bone healing properties were also improved in fracture healing model according to the results of micro-CT, mechanical test, and histological analysis. The current study confirms that the overexpression of mir-21 could promote osteogenesis and accelerate bone fracture healing, which may contribute to a new therapeutic way for fracture repair. Yuxin Sun, Liangliang Xu, Shuo Huang, Yonghui Hou, Yang Liu, Kai-Ming Chan, Xiao-Hua Pan, and Gang Li Copyright © 2015 Yuxin Sun et al. All rights reserved. Synthesis and Characterization of Biodegradable Polyurethane for Hypopharyngeal Tissue Engineering Sun, 08 Mar 2015 11:26:59 +0000 Biodegradable crosslinked polyurethane (cPU) was synthesized using polyethylene glycol (PEG), L-lactide (L-LA), and hexamethylene diisocyanate (HDI), with iron acetylacetonate (Fe(acac)3) as the catalyst and PEG as the extender. Chemical components of the obtained polymers were characterized by FTIR spectroscopy, 1H NMR spectra, and Gel Permeation Chromatography (GPC). The thermodynamic properties, mechanical behaviors, surface hydrophilicity, degradability, and cytotoxicity were tested via differential scanning calorimetry (DSC), tensile tests, contact angle measurements, and cell culture. The results show that the synthesized cPU possessed good flexibility with quite low glass transition temperature (, −22°C) and good wettability. Water uptake measured as high as 229.7 ± 18.7%. These properties make cPU a good candidate material for engineering soft tissues such as the hypopharynx. In vitro and in vivo tests showed that cPU has the ability to support the growth of human hypopharyngeal fibroblasts and angiogenesis was observed around cPU after it was implanted subcutaneously in SD rats. Zhisen Shen, Dakai Lu, Qun Li, Zongyong Zhang, and Yabin Zhu Copyright © 2015 Zhisen Shen et al. All rights reserved. Cooperative Regulation of Substrate Stiffness and Extracellular Matrix Proteins in Skin Wound Healing of Axolotls Sun, 08 Mar 2015 09:35:07 +0000 Urodele amphibians (Ambystoma mexicanum), unique among vertebrates, can regenerate appendages and other body parts entirely and functionally through a scar-free healing process. The wound epithelium covering the amputated or damaged site forms early and is essential for initiating the subsequent regenerative steps. However, the molecular mechanism through which the wound reepithelializes during regeneration remains unclear. In this study, we developed an in vitro culture system that mimics an in vivo wound healing process; the biomechanical properties in the system were precisely defined and manipulated. Skin explants that were cultured on 2 to 50 kPa collagen-coated substrates rapidly reepithelialized within 10 to 15 h; however, in harder (1 GPa) and other extracellular matrices (tenascin-, fibronectin-, and laminin-coated environments), the wound epithelium moved slowly. Furthermore, the reepithelialization rate of skin explants from metamorphic axolotls cultured on a polystyrene plate (1 GPa) increased substantially. These findings afford new insights and can facilitate investigating wound epithelium formation during early regeneration using biochemical and mechanical techniques. Ting-Yu Huang, Cheng-Han Wu, Mu-Hui Wang, Bo-Sung Chen, Ling-Ling Chiou, and Hsuan-Shu Lee Copyright © 2015 Ting-Yu Huang et al. All rights reserved. Hydroxyapatite Whisker Reinforced 63s Glass Scaffolds for Bone Tissue Engineering Wed, 04 Mar 2015 14:24:13 +0000 Bioactive glass (BG) is widely used for bone tissue engineering. However, poor mechanical properties are the major shortcomings. In the study, hydroxyapatite nanowhisker (HANw) was used as a reinforcement to improve the mechanical properties. 63s glass/HANw scaffolds were successfully fabricated by selective laser sintering (SLS). It was found that the optimal compressive strength and fracture toughness were achieved when 10 wt.% HANw was added. This led to 36% increase in compressive strength and 83% increase in fracture toughness, respectively, compared with pure 63s glass scaffolds. Different reinforcement mechanisms were analyzed based on the microstructure investigation. Whisker bridging and whisker pulling-out were efficient in absorbing crack propagating energy, resulting in the improvement of the mechanical properties. Moreover, bioactivity and biocompatibility of the scaffolds were evaluated in vitro. The results showed that composite scaffolds with 10 wt.% HANw exhibited good apatite-forming ability and cellular affinity. Cijun Shuai, Yiyuan Cao, Chengde Gao, Pei Feng, Tao Xiao, and Shuping Peng Copyright © 2015 Cijun Shuai et al. All rights reserved. Recent Developments in Vascular Imaging Techniques in Tissue Engineering and Regenerative Medicine Mon, 02 Mar 2015 07:56:14 +0000 Adequate vascularisation is key in determining the clinical outcome of stem cells and engineered tissue in regenerative medicine. Numerous imaging modalities have been developed and used for the visualization of vascularisation in tissue engineering. In this review, we briefly discuss the very recent advances aiming at high performance imaging of vasculature. We classify the vascular imaging modalities into three major groups: nonoptical methods (X-ray, magnetic resonance, ultrasound, and positron emission imaging), optical methods (optical coherence, fluorescence, multiphoton, and laser speckle imaging), and hybrid methods (photoacoustic imaging). We then summarize the strengths and challenges of these methods for preclinical and clinical applications. Paul Kumar Upputuri, Kathyayini Sivasubramanian, Chong Seow Khoon Mark, and Manojit Pramanik Copyright © 2015 Paul Kumar Upputuri et al. All rights reserved. Application of Bladder Acellular Matrix in Urinary Bladder Regeneration: The State of the Art and Future Directions Sun, 22 Feb 2015 09:46:55 +0000 Construction of the urinary bladder de novo using tissue engineering technologies is the “holy grail” of reconstructive urology. The search for the ideal biomaterial for urinary bladder reconstruction has been ongoing for decades. One of the most promising biomaterials for this purpose seems to be bladder acellular matrix (BAM). In this review we determine the most important factors, which may affect biological and physical properties of BAM and its regeneration potential in tissue engineered urinary bladder. We also point out the directions in modification of BAM, which include incorporation of exogenous growth factors into the BAM structure. Finally, we discuss the results of the urinary bladder regeneration with cell seeded BAM. Marta Pokrywczynska, Iga Gubanska, Gerard Drewa, and Tomasz Drewa Copyright © 2015 Marta Pokrywczynska et al. All rights reserved. Behaviour of Endothelial Cells in a Tridimensional In Vitro Environment Thu, 19 Feb 2015 10:19:00 +0000 Angiogenesis is a fundamental process in healing, tumor growth, and a variety of medical conditions. For this reason, in vitro angiogenesis is an area of interest for researchers. Additionally, in vitro angiogenesis is important for the survival of prevascularized tissue-engineering models. The aim of this study was to observe the self-tubular organization behaviour of endothelial cells in the self-assembly method. In this study, bilayered and dermal substitutes were prepared using the self-assembly method. Histological, immunostaining, and biochemical tests were performed. The behavioural dynamics of endothelial cells in this biological environment of supportive cells were observed, as were the steps of the in vitro angiogenic cascade with self-organizing capillary-like structures formation. The epidermal component of the substitutes was seen to promote network expansion and density. It also increased the quantity of angiogenic factors (VEGF and Ang-1) without increasing the proinflammatory factor (IL-8). In addition, the increased MMP activity contributed to matrix degradation, which facilitated capillary formation. Raif Eren Ayata, Stéphane Chabaud, Michèle Auger, and Roxane Pouliot Copyright © 2015 Raif Eren Ayata et al. All rights reserved. Hypergravity Stimulation Enhances PC12 Neuron-Like Cell Differentiation Mon, 16 Feb 2015 08:49:48 +0000 Altered gravity is a strong physical cue able to elicit different cellular responses, representing a largely uninvestigated opportunity for tissue engineering/regenerative medicine applications. Our recent studies have shown that both proliferation and differentiation of C2C12 skeletal muscle cells can be enhanced by hypergravity treatment; given these results, PC12 neuron-like cells were chosen to test the hypothesis that hypergravity stimulation might also affect the behavior of neuronal cells, in particular promoting an enhanced differentiated phenotype. PC12 cells were thus cultured under differentiating conditions for either 12 h or 72 h before being stimulated with different values of hypergravity (50 g and 150 g). Effects of hypergravity were evaluated at transcriptional level 1 h and 48 h after the stimulation, and at protein level 48 h from hypergravity exposure, to assess its influence on neurite development over increasing differentiation times. PC12 differentiation resulted strongly affected by the hypergravity treatments; in particular, neurite length was significantly enhanced after exposure to high acceleration values. The achieved results suggest that hypergravity might induce a faster and higher neuronal differentiation and encourage further investigations on the potential of hypergravity in the preparation of cellular constructs for regenerative medicine and tissue engineering purposes. Giada Graziana Genchi, Francesca Cialdai, Monica Monici, Barbara Mazzolai, Virgilio Mattoli, and Gianni Ciofani Copyright © 2015 Giada Graziana Genchi et al. All rights reserved. Acoustic-Frequency Vibratory Stimulation Regulates the Balance between Osteogenesis and Adipogenesis of Human Bone Marrow-Derived Mesenchymal Stem Cells Sun, 08 Feb 2015 11:23:09 +0000 Osteoporosis can be associated with the disordered balance between osteogenesis and adipogenesis of bone marrow-derived mesenchymal stem cells (BM-MSCs). Although low-frequency mechanical vibration has been demonstrated to promote osteogenesis, little is known about the influence of acoustic-frequency vibratory stimulation (AFVS). BM-MSCs were subjected to AFVS at frequencies of 0, 30, 400, and 800 Hz and induced toward osteogenic or adipogenic-specific lineage. Extracellular matrix mineralization was determined by Alizarin Red S staining and lipid accumulation was assessed by Oil Red O staining. Transcript levels of osteogenic and adipogenic marker genes were evaluated by real-time reverse transcription-polymerase chain reaction. Cell proliferation of BM-MSCs was promoted following exposure to AFVS at 800 Hz. Vibration at 800 Hz induced the highest level of calcium deposition and significantly increased mRNA expression of COL1A1, ALP, RUNX2, and SPP1. The 800 Hz group downregulated lipid accumulation and levels of adipogenic genes, including FABP4, CEBPA, PPARG, and LEP, while vibration at 30 Hz supported adipogenesis. BM-MSCs showed a frequency-dependent response to acoustic vibration. AFVS at 800 Hz was the most favorable for osteogenic differentiation and simultaneously suppressed adipogenesis. Thus, acoustic vibration could potentially become a novel means to prevent and treat osteoporosis. Xi Chen, Fan He, Dong-Yan Zhong, and Zong-Ping Luo Copyright © 2015 Xi Chen et al. All rights reserved. A Therapeutic Strategy for Spinal Cord Defect: Human Dental Follicle Cells Combined with Aligned PCL/PLGA Electrospun Material Wed, 28 Jan 2015 06:57:19 +0000 Stem cell implantation has been utilized for the repair of spinal cord injury; however, it shows unsatisfactory performance in repairing large scale lesion of an organ. We hypothesized that dental follicle cells (DFCs), which possess multipotential capability, could reconstruct spinal cord defect (SCD) in combination with biomaterials. In the present study, mesenchymal and neurogenic lineage characteristics of human DFCs (hDFCs) were identified. Aligned electrospun PCL/PLGA material (AEM) was fabricated and it would not lead to cytotoxic reaction; furthermore, hDFCs could stretch along the oriented fibers and proliferate efficiently on AEM. Subsequently, hDFCs seeded AEM was transplanted to restore the defect in rat spinal cord. Functional observation was performed but results showed no statistical significance. The following histologic analyses proved that AEM allowed nerve fibers to pass through, and implanted hDFCs could express oligodendrogenic lineage maker Olig2 in vivo which was able to contribute to remyelination. Therefore, we concluded that hDFCs can be a candidate resource in neural regeneration. Aligned electrospun fibers can support spinal cord structure and induce cell/tissue polarity. This strategy can be considered as alternative proposals for the SCD regeneration studies. Xinghan Li, Chao Yang, Lei Li, Jie Xiong, Li Xie, Bo Yang, Mei Yu, Lian Feng, Zongting Jiang, Weihua Guo, and Weidong Tian Copyright © 2015 Xinghan Li et al. All rights reserved. Hematopoietic Stem and Progenitor Cells Can Be Enriched by Implanting Biomaterial into Spatium Intermusculare Wed, 28 Jan 2015 06:22:21 +0000 Hematopoietic stem and progenitor cells (HSPCs) have been used successfully to treat patients with cancer and disorders of the blood and immune systems. In this study, we tried to enrich HSPCs by implanting biomaterials into the spatium intermusculare of mice hind limbs. Gelatine sponges were implanted into the spatium intermusculare of mice and then retrieved after 12 days. The presence of HSPCs in the migrating cells (MCs) was detected by phenotypically probing with CD34+Sca-1+ and functionally confirming the presence of using colony-forming cell assay and assessing the long-term reconstitution ability. The frequency of CD34+, Sca-1+, and CD34+Sca-1+ cells and colony formation unit in the MCs was much higher than that in the bone marrow (BM). Moreover, transplanted MCs were able to home to BM, muscle, and spleen, which induced an efficient long-term hematopoietic reconstitution in vivo. In addition, HSPCs within the MCs originated from the BM. Furthermore, the administration of G-CSF greatly reduced the time of implantation, and increased the number of MCs and frequency of HSPCs in the MCs. These data provide compelling evidence that HSPCs can be enriched by implanting biomaterial into spatium intermusculare. Implantation of biomaterial may be seen as the first step to a proof of their applicability to clinical practice in enriching HSPCs. Jia-Bei Tong, Xiao-Yun Wu, Ge-Liuchang Jia, Kui-Jun Zhao, Shi-Li Wang, and Zhi-Jie Ma Copyright © 2015 Jia-Bei Tong et al. All rights reserved. Activation of Cannabinoid Receptor 2 Enhances Osteogenic Differentiation of Bone Marrow Derived Mesenchymal Stem Cells Wed, 21 Jan 2015 13:08:46 +0000 Bone marrow derived mesenchymal stem cells (BM-MSCs) are considered as the most promising cells source for bone engineering. Cannabinoid (CB) receptors play important roles in bone mass turnover. The aim of this study is to test if activation of CB2 receptor by chemical agonist could enhance the osteogenic differentiation and mineralization in bone BM-MSCs. Alkaline phosphatase (ALP) activity staining and real time PCR were performed to test the osteogenic differentiation. Alizarin red staining was carried out to examine the mineralization. Small interference RNA (siRNA) was used to study the role of CB2 receptor in osteogenic differentiation. Results showed activation of CB2 receptor increased ALP activity, promoted expression of osteogenic genes, and enhanced deposition of calcium in extracellular matrix. Knockdown of CB2 receptor by siRNA inhibited ALP activity and mineralization. Results of immunofluorescent staining showed that phosphorylation of p38 MAP kinase is reduced by knocking down of CB2 receptor. Finally, bone marrow samples demonstrated that expression of CB2 receptor is much lower in osteoporotic patients than in healthy donors. Taken together, data from this study suggested that activation of CB2 receptor plays important role in osteogenic differentiation of BM-MSCs. Lack of CB2 receptor may be related to osteoporosis. Yong-Xin Sun, Ai-Hua Xu, Yang Yang, Jia-Xing Zhang, and Ai-Wen Yu Copyright © 2015 Yong-Xin Sun et al. All rights reserved. Biofunctionalized Nanofibers Using Arthrospira (Spirulina) Biomass and Biopolymer Thu, 15 Jan 2015 11:25:48 +0000 Electrospun nanofibers composed of polymers have been extensively researched because of their scientific and technical applications. Commercially available polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-valerate (PHB-HV) copolymers are good choices for such nanofibers. We used a highly integrated method, by adjusting the properties of the spinning solutions, where the cyanophyte Arthrospira (formally Spirulina) was the single source for nanofiber biofunctionalization. We investigated nanofibers using PHB extracted from Spirulina and the bacteria Cupriavidus necator and compared the nanofibers to those made from commercially available PHB and PHB-HV. Our study assessed nanofiber formation and their selected thermal, mechanical, and optical properties. We found that nanofibers produced from Spirulina PHB and biofunctionalized with Spirulina biomass exhibited properties which were equal to or better than nanofibers made with commercially available PHB or PHB-HV. Our methodology is highly promising for nanofiber production and biofunctionalization and can be used in many industrial and life science applications. Michele Greque de Morais, Christopher Stillings, Roland Dersch, Markus Rudisile, Patrícia Pranke, Jorge Alberto Vieira Costa, and Joachim Wendorff Copyright © 2015 Michele Greque de Morais et al. All rights reserved. ECM-Like Scaffolds: Nature Drives Research Sun, 28 Dec 2014 06:24:59 +0000 Costantino Del Gaudio, Silvia Baiguera, Alessandra Bianco, and Luca Urbani Copyright © 2014 Costantino Del Gaudio et al. All rights reserved. Bone Tissue Engineering for Dentistry and Orthopaedics Wed, 26 Nov 2014 08:24:13 +0000 Yin Xiao Copyright © 2014 Yin Xiao. All rights reserved. 3D Dynamic Culture of Rabbit Articular Chondrocytes Encapsulated in Alginate Gel Beads Using Spinner Flasks for Cartilage Tissue Regeneration Mon, 24 Nov 2014 11:36:22 +0000 Cell-based therapy using chondrocytes for cartilage repair suffers from chondrocyte dedifferentiation. In the present study, the effects of an integrated three-dimensional and dynamic culture on rabbit articular chondrocytes were investigated. Cells (passages 1 and 4) were encapsulated in alginate gel beads and cultured in spinner flasks in chondrogenic and chondrocyte growth media. Subcutaneous implantation of the cell-laden beads was performed to evaluate the ectopic chondrogenesis. It was found that cells remained viable after 35 days in the three-dimensional dynamic culture. Passage 1 cells demonstrated a proliferative growth in both media. Passage 4 cells showed a gradual reduction in DNA content in growth medium, which was attenuated in chondrogenic medium. Deposition of glycosaminoglycans (GAG) was found in all cultures. While passage 1 cells generally produced higher amounts of GAG than passage 4 cells, GAG/DNA became similar on day 35 for both cells in growth media. Interestingly, GAG/DNA in growth medium was greater than that in chondrogenic medium for both cells. Based on GAG quantification and gene expression analysis, encapsulated passage 1 cells cultured in growth medium displayed the best ectopic chondrogenesis. Taken together, the three-dimensional and dynamic culture for chondrocytes holds great potential in cartilage regeneration. Feiyue Xu, Lei Xu, Qi Wang, Zhaoyang Ye, Yan Zhou, and Wen-Song Tan Copyright © 2014 Feiyue Xu et al. All rights reserved. Periodontal Ligament Mesenchymal Stromal Cells Increase Proliferation and Glycosaminoglycans Formation of Temporomandibular Joint Derived Fibrochondrocytes Mon, 10 Nov 2014 14:01:28 +0000 Objectives. Temporomandibular joint (TMJ) disorders are common disease in maxillofacial surgery. The aim of this study is to regenerate fibrocartilage with a mixture of TMJ fibrochondrocytes and periodontal ligament derived mesenchymal stem cells (PD-MSCs). Materials and Methods. Fibrochondrocytes and PD-MSC were cocultured (ratio 1 : 1) for 3 weeks. Histology and glycosaminoglycans (GAGs) assay were performed to examine the deposition of GAG. Green florescent protein (GFP) was used to track PD-MSC. Conditioned medium of PD-MSCs was collected to study the soluble factors. Gene expression of fibrochondrocytes cultured in conditioned medium was tested by quantitative PCR (qPCR). Results. Increased proliferation of TMJ-CH was observed in coculture pellets when compared to monoculture. Enhanced GAG production in cocultures was shown by histology and GAG quantification. Tracing of GFP revealed the fact that PD-MSC disappears after coculture with TMJ-CH for 3 weeks. In addition, conditioned medium of PD-MSC was also shown to increase the proliferation and GAG deposition of TMJ-CH. Meanwhile, results of qPCR demonstrated that conditioned medium enhanced the expression levels of matrix-related genes in TMJ-CH. Conclusions. Results from this study support the mechanism of MSC-chondrocyte interaction, in which MSCs act as secretor of soluble factors that stimulate proliferation and extracellular matrix deposition of chondrocytes. Jianli Zhang, Fujun Guo, Jianqiang Mi, and Zhiye Zhang Copyright © 2014 Jianli Zhang et al. All rights reserved. Age Dependent Differences in Collagen Alignment of Glutaraldehyde Fixed Bovine Pericardium Sun, 14 Sep 2014 10:31:34 +0000 Bovine pericardium is used for heart valve leaflet replacement where the strength and thinness are critical properties. Pericardium from neonatal animals (4–7 days old) is advantageously thinner and is considered as an alternative to that from adult animals. Here, the structures of adult and neonatal bovine pericardium tissues fixed with glutaraldehyde are characterized by synchrotron-based small angle X-ray scattering (SAXS) and compared with the mechanical properties of these materials. Significant differences are observed between adult and neonatal tissue. The glutaraldehyde fixed neonatal tissue has a higher modulus of elasticity (83.7 MPa) than adult pericardium (33.5 MPa) and a higher normalised ultimate tensile strength (32.9 MPa) than adult pericardium (19.1 MPa). Measured edge on to the tissue, the collagen in neonatal pericardium is significantly more aligned (orientation index (OI) 0.78) than that in adult pericardium (OI 0.62). There is no difference in the fibril diameter between neonatal and adult pericardium. It is shown that high alignment in the plane of the tissue provides the mechanism for the increased strength of the neonatal material. The superior strength of neonatal compared with adult tissue supports the use of neonatal bovine pericardium in heterografts. Katie H. Sizeland, Hannah C. Wells, John Higgins, Crystal M. Cunanan, Nigel Kirby, Adrian Hawley, Stephen T. Mudie, and Richard G. Haverkamp Copyright © 2014 Katie H. Sizeland et al. All rights reserved. Tissue Engineered Scaffolds for an Effective Healing and Regeneration: Reviewing Orthotopic Studies Wed, 27 Aug 2014 07:11:58 +0000 It is commonly stated that tissue engineering is the most promising approach to treat or replace failing tissues/organs. For this aim, a specific strategy should be planned including proper selection of biomaterials, fabrication techniques, cell lines, and signaling cues. A great effort has been pursued to develop suitable scaffolds for the restoration of a variety of tissues and a huge number of protocols ranging from in vitro to in vivo studies, the latter further differentiating into several procedures depending on the type of implantation (i.e., subcutaneous or orthotopic) and the model adopted (i.e., animal or human), have been developed. All together, the published reports demonstrate that the proposed tissue engineering approaches spread toward multiple directions. The critical review of this scenario might suggest, at the same time, that a limited number of studies gave a real improvement to the field, especially referring to in vivo investigations. In this regard, the present paper aims to review the results of in vivo tissue engineering experimentations, focusing on the role of the scaffold and its specificity with respect to the tissue to be regenerated, in order to verify whether an extracellular matrix-like device, as usually stated, could promote an expected positive outcome. Silvia Baiguera, Luca Urbani, and Costantino Del Gaudio Copyright © 2014 Silvia Baiguera et al. All rights reserved. Designer Self-Assembling Peptide Nanofiber Scaffolds Containing Link Protein N-Terminal Peptide Induce Chondrogenesis of Rabbit Bone Marrow Stem Cells Tue, 26 Aug 2014 13:06:35 +0000 Designer self-assembling peptide nanofiber hydrogel scaffolds have been considered as promising biomaterials for tissue engineering because of their excellent biocompatibility and biofunctionality. Our previous studies have shown that a novel designer functionalized self-assembling peptide nanofiber hydrogel scaffold (RLN/RADA16, LN-NS) containing N-terminal peptide sequence of link protein (link N) can promote nucleus pulposus cells (NPCs) adhesion and three-dimensional (3D) migration and stimulate biosynthesis of type II collagen and aggrecan by NPCs in vitro. The present study has extended these investigations to determine the effects of this functionalized LN-NS on bone marrow stem cells (BMSCs), a potential cell source for NP regeneration. Although the functionalized LN-NS cannot promote BMSCs proliferation, it significantly promotes BMSCs adhesion compared with that of the pure RADA16 hydrogel scaffold. Moreover, the functionalized LN-NS remarkably stimulates biosynthesis and deposition of type II collagen and aggrecan. These data demonstrate that the functionalized peptide nanofiber hydrogel scaffold containing link N peptide as a potential matrix substrate will be very useful in the NP tissue regeneration. Baichuan Wang, Caixia Sun, Zengwu Shao, Shuhua Yang, Biao Che, Qiang Wu, and Jianxiang Liu Copyright © 2014 Baichuan Wang et al. All rights reserved. Cell/Tissue Microenvironment Engineering and Monitoring in Tissue Engineering, Regenerative Medicine, and In Vitro Tissue Models Tue, 26 Aug 2014 07:28:46 +0000 Nihal Engin Vrana, Vasif Hasirci, Garrett Brian McGuinness, and Albana Ndreu-Halili Copyright © 2014 Nihal Engin Vrana et al. All rights reserved. Bone Tissue Engineering: Cell Motility, Vascularization, Micro-Nano Scaffolding, and Remodeling Tue, 19 Aug 2014 11:52:23 +0000 Guo-Xian Pei, Yi-Xian Qin, Dietmar Werner Hutmacher, and Zhi-Yong Zhang Copyright © 2014 Guo-Xian Pei et al. All rights reserved. Mechanotransduction in Musculoskeletal Tissue Regeneration: Effects of Fluid Flow, Loading, and Cellular-Molecular Pathways Mon, 18 Aug 2014 07:50:39 +0000 While mechanotransductive signal is proven essential for tissue regeneration, it is critical to determine specific cellular responses to such mechanical signals and the underlying mechanism. Dynamic fluid flow induced by mechanical loading has been shown to have the potential to regulate bone adaptation and mitigate bone loss. Mechanotransduction pathways are of great interests in elucidating how mechanical signals produce such observed effects, including reduced bone loss, increased bone formation, and osteogenic cell differentiation. The objective of this review is to develop a molecular understanding of the mechanotransduction processes in tissue regeneration, which may provide new insights into bone physiology. We discussed the potential for mechanical loading to induce dynamic bone fluid flow, regulation of bone adaptation, and optimization of stimulation parameters in various loading regimens. The potential for mechanical loading to regulate microcirculation is also discussed. Particularly, attention is allotted to the potential cellular and molecular pathways in response to loading, including osteocytes associated with Wnt signaling, elevation of marrow stem cells, and suppression of adipotic cells, as well as the roles of LRP5 and microRNA. These data and discussions highlight the complex yet highly coordinated process of mechanotransduction in bone tissue regeneration. Yi-Xian Qin and Minyi Hu Copyright © 2014 Yi-Xian Qin and Minyi Hu. All rights reserved. A Low Protein Diet Alters Bone Material Level Properties and the Response to In Vitro Repeated Mechanical Loading Thu, 14 Aug 2014 11:35:00 +0000 Low protein intake is associated with an alteration of bone microstructure and material level properties. However, it remains unknown whether these alterations of bone tissue could influence the response to repeated mechanical loading. The authors investigated the in vitro effect of repeated loading on bone strength in humeri collected from 20 6-month-old female rats pair-fed with a control (15% casein) or an isocaloric low protein (2.5% casein) diet for 10 weeks. Bone specimens were cyclically loaded in three-point bending under load control for 2000 cycles. Humeri were then monotonically loaded to failure. The load-displacement curve of the in vitro cyclically loaded humerus was compared to the contralateral noncyclically loaded humerus and the influence of both protein diets. Material level properties were also evaluated through a nanoindentation test. Cyclic loading decreased postyield load and plastic deflection in rats fed a low protein diet, but not in those on a regular diet. Bone material level properties were altered in rats fed a low protein diet. This suggests that bone biomechanical alterations consequent to cyclic loading are more likely to occur in rats fed a low protein diet than in control animals subjected to the same in vitro cyclic loading regimen. Victor Dubois-Ferrière, René Rizzoli, and Patrick Ammann Copyright © 2014 Victor Dubois-Ferrière et al. All rights reserved. Cartilage Repair and Subchondral Bone Migration Using 3D Printing Osteochondral Composites: A One-Year-Period Study in Rabbit Trochlea Thu, 07 Aug 2014 07:37:16 +0000 Increasing evidences show that subchondral bone may play a significant role in the repair or progression of cartilage damage in situ. However, the exact change of subchondral bone during osteochondral repair is still poorly understood. In this paper, biphasic osteochondral composite scaffolds were fabricated by 3D printing technology using PEG hydrogel and β-TCP ceramic and then implanted in rabbit trochlea within a critical size defect model. Animals were euthanized at 1, 2, 4, 8, 16, 24, and 52 weeks after implantation. Histological results showed that hyaline-like cartilage formed along with white smooth surface and invisible margin at 24 weeks postoperatively, typical tidemark formation at 52 weeks. The repaired subchondral bone formed from 16 to 52 weeks in a “flow like” manner from surrounding bone to the defect center gradually. Statistical analysis illustrated that both subchondral bone volume and migration area percentage were highly correlated with the gross appearance Wayne score of repaired cartilage. Therefore, subchondral bone migration is related to cartilage repair for critical size osteochondral defects. Furthermore, the subchondral bone remodeling proceeds in a “flow like” manner and repaired cartilage with tidemark implies that the biphasic PEG/β-TCP composites fabricated by 3D printing provides a feasible strategy for osteochondral tissue engineering application. Weijie Zhang, Qin Lian, Dichen Li, Kunzheng Wang, Dingjun Hao, Weiguo Bian, Jiankang He, and Zhongmin Jin Copyright © 2014 Weijie Zhang et al. All rights reserved. Recent Advances in Application of Biosensors in Tissue Engineering Wed, 06 Aug 2014 07:25:30 +0000 Biosensors research is a fast growing field in which tens of thousands of papers have been published over the years, and the industry is now worth billions of dollars. The biosensor products have found their applications in numerous industries including food and beverages, agricultural, environmental, medical diagnostics, and pharmaceutical industries and many more. Even though numerous biosensors have been developed for detection of proteins, peptides, enzymes, and numerous other biomolecules for diverse applications, their applications in tissue engineering have remained limited. In recent years, there has been a growing interest in application of novel biosensors in cell culture and tissue engineering, for example, real-time detection of small molecules such as glucose, lactose, and H2O2 as well as serum proteins of large molecular size, such as albumin and alpha-fetoprotein, and inflammatory cytokines, such as IFN-g and TNF-α. In this review, we provide an overview of the recent advancements in biosensors for tissue engineering applications. Anwarul Hasan, Md Nurunnabi, Mahboob Morshed, Arghya Paul, Alessandro Polini, Tapas Kuila, Moustafa Al Hariri, Yong-kyu Lee, and Ayad A. Jaffa Copyright © 2014 Anwarul Hasan et al. All rights reserved. Characterization of Human Vaginal Mucosa Cells for Autologous In Vitro Cultured Vaginal Tissue Transplantation in Patients with MRKH Syndrome Tue, 05 Aug 2014 09:42:07 +0000 Mayer-Rokitansky-Küster-Hauser (MRKH) is a rare syndrome characterized by congenital aplasia of the uterus and vagina. The most common procedure used for surgical reconstruction of the neovagina is the McIndoe vaginoplasty, which consists in creation of a vaginal canal covered with a full-thickness skin graft. Here we characterized the autologous in vitro cultured vaginal tissue proposed as alternative material in our developed modified McIndoe vaginoplasty in order to underlie its importance in autologous total vaginal replacement. To this aim human vaginal mucosa cells (HVMs) were isolated from vaginal mucosa of patients affected by MRKH syndrome and characterized with respect to growth kinetics, morphology, PAS staining, and expression of specific epithelial markers by immunofluorescence, Western blot, and qRT-PCR analyses. The presence of specific epithelial markers along with the morphology and the presence of mucified cells demonstrated the epithelial nature of HMVs, important for an efficient epithelialization of the neovagina walls and for creating a functional vaginal cavity. Moreover, these cells presented characteristics of effective proliferation as demonstrated by growth kinetics assay. Therefore, the autologous in vitro cultured vaginal tissue might represent a highly promising and valid material for McIndoe vaginoplasty. Cristina Nodale, Enrica Vescarelli, Sirio D’Amici, Diana Maffucci, Simona Ceccarelli, Marco Monti, Pierluigi Benedetti Panici, Ferdinando Romano, Antonio Angeloni, and Cinzia Marchese Copyright © 2014 Cristina Nodale et al. All rights reserved. Tailored PVA/ECM Scaffolds for Cartilage Regeneration Thu, 24 Jul 2014 07:17:01 +0000 Articular cartilage lesions are a particular challenge for regenerative medicine due to cartilage low self-ability repair in case of damage. Hence, a significant goal of musculoskeletal tissue engineering is the development of suitable structures in virtue of their matrix composition and biomechanical properties. The objective of our study was to design in vitro a supporting structure for autologous chondrocyte growth. We realized a biohybrid composite scaffold combining a novel and nonspecific extracellular matrix (ECM), which is decellularized Wharton’s jelly ECM, with the biomechanical properties of the synthetic hydrogel polyvinyl alcohol (PVA). Wharton’s jelly ECM was tested for its ability in promoting scaffold colonization by chondrocytes and compared with polyvinyl alcohol itself and the more specific decellularized cartilage matrix. Our preliminary evidences highlighted the chance of using Wharton’s jelly ECM in combination with PVA hydrogels as an innovative and easily available scaffold for cartilage restoration. Elena Stocco, Silvia Barbon, Daniele Dalzoppo, Silvano Lora, Leonardo Sartore, Marcella Folin, Pier Paolo Parnigotto, and Claudio Grandi Copyright © 2014 Elena Stocco et al. All rights reserved. Biological Effects of Spirulina (Arthrospira) Biopolymers and Biomass in the Development of Nanostructured Scaffolds Wed, 23 Jul 2014 09:34:32 +0000 Spirulina is produced from pure cultures of the photosynthetic prokaryotic cyanobacteria Arthrospira. For many years research centers throughout the world have studied its application in various scientific fields, especially in foods and medicine. The biomass produced from Spirulina cultivation contains a variety of biocompounds, including biopeptides, biopolymers, carbohydrates, essential fatty acids, minerals, oligoelements, and sterols. Some of these compounds are bioactive and have anti-inflammatory, antibacterial, antioxidant, and antifungal properties. These compounds can be used in tissue engineering, the interdisciplinary field that combines techniques from cell science, engineering, and materials science and which has grown in importance over the past few decades. Spirulina biomass can be used to produce polyhydroxyalkanoates (PHAs), biopolymers that can substitute synthetic polymers in the construction of engineered extracellular matrices (scaffolds) for use in tissue cultures or bioactive molecule construction. This review describes the development of nanostructured scaffolds based on biopolymers extracted from microalgae and biomass from Spirulina production. These scaffolds have the potential to encourage cell growth while reducing the risk of organ or tissue rejection. Michele Greque de Morais, Bruna da Silva Vaz, Etiele Greque de Morais, and Jorge Alberto Vieira Costa Copyright © 2014 Michele Greque de Morais et al. All rights reserved. Bone Tissue Engineering and Regeneration Tue, 22 Jul 2014 09:31:22 +0000 Benjamin Levi, Bruno Péault, and Aaron W. James Copyright © 2014 Benjamin Levi et al. All rights reserved. Cell Microenvironment Engineering and Monitoring for Tissue Engineering and Regenerative Medicine: The Recent Advances Sun, 20 Jul 2014 00:00:00 +0000 In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells’ behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future. Julien Barthes, Hayriye Özçelik, Mathilde Hindié, Albana Ndreu-Halili, Anwarul Hasan, and Nihal Engin Vrana Copyright © 2014 Julien Barthes et al. All rights reserved. Blood Vessel-Derived Acellular Matrix for Vascular Graft Application Wed, 16 Jul 2014 11:51:20 +0000 To overcome the issues connected to the use of autologous vascular grafts and artificial materials for reconstruction of small diameter (<6 mm) blood vessels, this study aimed to develop acellular matrix- (AM-) based vascular grafts. Rat iliac arteries were decellularized by a detergent-enzymatic treatment, whereas endothelial cells (ECs) were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Sixteen female Lewis rats (8 weeks old) received only AM or previously in vitro reendothelialized AM as abdominal aorta interposition grafts (about 1 cm). The detergent-enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. One month after surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM preseeded with ECs could be a promising approach for the replacement of blood vessels. Luigi Dall’Olmo, Ilenia Zanusso, Rosa Di Liddo, Tatiana Chioato, Thomas Bertalot, Enrica Guidi, and Maria Teresa Conconi Copyright © 2014 Luigi Dall’Olmo et al. All rights reserved. Preparation of Three-Dimensional Vascularized MSC Cell Sheet Constructs for Tissue Regeneration Tue, 08 Jul 2014 09:46:23 +0000 Engineering three-dimensional (3D) vascularized constructs remains a challenge due to the inability to form rich microvessel networks. In this study we engineered a prevascularized 3D cell sheet construct for tissue regeneration using human bone marrow-derived mesenchymal stem cells (hMSCs) and human umbilical vein endothelial cells as cell sources. hMSCs were cultured to form a thick cell sheet, and human umbilical vein endothelial cells (HUVECs) were then seeded on the hMSCs sheet to form networks. The single prevascularized HUVEC/hMSC cell sheet was folded to form a 3D construct by a modified cell sheet engineering technique. In vitro results indicated that the hMSCs cell sheet promoted the HUVECs cell migration to form networks in horizontal and vertical directions. In vivo results showed that many blood vessels grew into the 3D HUVEC/hMSC cell sheet constructs after implanted in the subcutaneous pocket of immunodeficient mice. The density of blood vessels in the prevascularized constructs was higher than that in the nonprevascularized constructs. Immunohistochemistry staining further showed that in vitro preformed human capillaries in the prevascularized constructs anastomosed with the host vasculature to form functional blood vessels. These results suggest the promising potential of this 3D prevascularized construct using hMSCs cell sheet as a platform for wide applications in engineering vascularized tissues. Liling Ren, Dongyang Ma, Bin Liu, Jinda Li, Jia Chen, Dan Yang, and Peng Gao Copyright © 2014 Liling Ren et al. All rights reserved. Repair of Segmental Load-Bearing Bone Defect by Autologous Mesenchymal Stem Cells and Plasma-Derived Fibrin Impregnated Ceramic Block Results in Early Recovery of Limb Function Tue, 08 Jul 2014 00:00:00 +0000 Calcium phosphate-based bone substitutes have not been used to repair load-bearing bone defects due to their weak mechanical property. In this study, we reevaluated the functional outcomes of combining ceramic block with osteogenic-induced mesenchymal stem cells and platelet-rich plasma (TEB) to repair critical-sized segmental tibial defect. Comparisons were made with fresh marrow-impregnated ceramic block (MIC) and partially demineralized allogeneic bone block (ALLO). Six New Zealand White female rabbits were used in each study group and three rabbits with no implants were used as negative controls. By Day 90, 4/6 rabbits in TEB group and 2/6 in ALLO and MIC groups resumed normal gait pattern. Union was achieved significantly faster in TEB group with a radiological score of 4.50 ± 0.78 versus ALLO (1.06 ± 0.32), MIC (1.28 ± 0.24), and negative controls (0). Histologically, TEB group scored the highest percentage of new bone (82% ± 5.1%) compared to ALLO (5% ± 2.5%) and MIC (26% ± 5.2%). Biomechanically, TEB-treated tibiae achieved the highest compressive strength (43.50 ± 12.72 MPa) compared to those treated with ALLO (15.15 ± 3.57 MPa) and MIC (23.28 ± 6.14 MPa). In conclusion, TEB can repair critical-sized segmental load-bearing bone defects and restore limb function. Min Hwei Ng, Suryasmi Duski, Kok Keong Tan, Mohd Reusmaazran Yusof, Kiat Cheong Low, Isa Mohamed Rose, Zahiah Mohamed, Aminuddin Bin Saim, and Ruszymah Bt Hj Idrus Copyright © 2014 Min Hwei Ng et al. All rights reserved. Prevention of Peritendinous Adhesions Using an Electrospun DegraPol Polymer Tube: A Histological, Ultrasonographic, and Biomechanical Study in Rabbits Wed, 02 Jul 2014 14:10:34 +0000 Purpose. One of the great challenges in surgical tendon rupture repair is to minimize peritendinous adhesions. In order to reduce adhesion formation, a physical barrier was applied to a sutured rabbit Achilles tendon, with two different immobilization protocols used postoperatively. Methods. Thirty New Zealand white rabbits received a laceration on the Achilles tendon, sutured with a 4-strand Becker suture, and half of the rabbits got a DegraPol tube at the repair site. While fifteen rabbits had their treated hind leg in a 180° stretched position during 6 weeks (adhesion provoking immobilization), the other fifteen rabbits were recasted with a 150° position after 3 weeks (adhesion inhibiting immobilization). Adhesion extent was analysed macroscopically, via ultrasound and histology. Inflammation was determined histologically. Biomechanical properties were analysed. Results. Application of a DegraPol tube reduced adhesion formation by approximately 20%—independently of the immobilization protocol. Biomechanical properties of extracted specimen were not affected by the tube application. There was no serious inflammatory reaction towards the implant material. Conclusions. Implantation of a DegraPol tube tightly set around a sutured tendon acts as a beneficial physical barrier and prevents adhesion formation significantly—without affecting the tendon healing process. Gabriella Meier Bürgisser, Maurizio Calcagni, Angela Müller, Eliana Bonavoglia, Gion Fessel, Jess G. Snedeker, Pietro Giovanoli, and Johanna Buschmann Copyright © 2014 Gabriella Meier Bürgisser et al. All rights reserved. Repairing the Osteochondral Defect in Goat with the Tissue-Engineered Osteochondral Graft Preconstructed in a Double-Chamber Stirring Bioreactor Wed, 02 Jul 2014 00:00:00 +0000 To investigate the reparative efficacy of tissue-engineered osteochondral (TEO) graft for repairing the osteochondral defect in goat, we designed a double-chamber stirring bioreactor to construct the bone and cartilage composites simultaneously in one β-TCP scaffold and observed the reparative effect in vivo. The osteochondral defects were created in goats and all the animals were divided into 3 groups randomly. In groups A, the defect was treated with the TEO which was cultured with mechanical stimulation of stir; in group B, the defect was treated with TEO which was cultured without mechanical stimulation of stir; in groups C, the defect was treated without TEO. At 12 weeks and 24 weeks after operation, the reparative effects in different groups were assessed and compared. The results indicated that the reparative effect of the TEO cultured in the bioreactor was better than the control group, and mechanical stimulation of stir could further improve the reparative effect. We provided a feasible and effective method to construct the TEO for treatment of osteochondral defect using autologous BMSCs and the double-chamber bioreactor. Yang Pei, Jun-jun Fan, Xiao-qiang Zhang, Zhi-yong Zhang, and Min Yu Copyright © 2014 Yang Pei et al. All rights reserved. Different Effects of Implanting Sensory Nerve or Blood Vessel on the Vascularization, Neurotization, and Osteogenesis of Tissue-Engineered Bone In Vivo Mon, 30 Jun 2014 11:15:05 +0000 To compare the different effects of implanting sensory nerve tracts or blood vessel on the osteogenesis, vascularization, and neurotization of the tissue-engineered bone in vivo, we constructed the tissue engineered bone and implanted the sensory nerve tracts (group SN), blood vessel (group VB), or nothing (group Blank) to the side channel of the bone graft to repair the femur defect in the rabbit. Better osteogenesis was observed in groups SN and VB than in group Blank, and no significant difference was found between groups SN and VB at 4, 8, and 12 weeks postoperatively. The neuropeptides expression and the number of new blood vessels in the bone tissues were increased at 8 weeks and then decreased at 12 weeks in all groups and were highest in group VB and lowest in group Blank at all three time points. We conclude that implanting either blood vessel or sensory nerve tract into the tissue-engineered bone can significantly enhance both the vascularization and neurotization simultaneously to get a better osteogenesis effect than TEB alone, and the method of implanting blood vessel has a little better effect of vascularization and neurotization but almost the same osteogenesis effect as implanting sensory nerve. Jun-jun Fan, Tian-wang Mu, Jun-jun Qin, Long Bi, and Guo-xian Pei Copyright © 2014 Jun-jun Fan et al. All rights reserved. Local Sympathetic Denervation of Femoral Artery in a Rabbit Model by Using 6-Hydroxydopamine In Situ Mon, 30 Jun 2014 08:52:42 +0000 Both artery bundle and sympathetic nerve were involved with the metabolism of bone tissues. Whether the enhancing effects of artery bundle result from its accompanying sympathetic nerve or blood supply is still unknown. There is no ideal sympathetic nerve-inhibited method for the in situ denervation of artery bundle. Therefore, we dipped the femoral artery in the 6-hydroxydopamine (6-OHDA) locally and observed its effect. Compared with control group, the in situ treatment of 6-OHDA did not damage the normal structure of vascular bundle indicated by hematoxylin-eosin (HE) staining. However, the functions of sympathetic nerve was completely inhibited for more than 2 weeks, and only a few function of sympathetic nerve resumed 4 weeks later, evidenced by glyoxylic acid staining and the expression of tyrosine hydroxylase (TH) and nerve peptide Y (NPY). Thus, 6-OHDA is promising as an ideal reagent for the local denervation of sympathetic nerve from artery system. Yufei Jin, Junjun Fan, Fuhang Li, Long Bi, and Guoxian Pei Copyright © 2014 Yufei Jin et al. All rights reserved. Effect of Thickness of HA-Coating on Microporous Silk Scaffolds Using Alternate Soaking Technology Sun, 29 Jun 2014 08:21:06 +0000 Hydroxyapatite (HA) can be coated on various materials surface and has the function of osteogenicity. Microporous silk scaffold has excellent biocompatibility. In this study, alternate soaking technology was used to coat HA on microporous silk scaffolds. However, the cell proliferation was found to decrease with the increasing thickness (cycles of soaking) of HA-coating. This study aims to determine the best thickness (cycles of soaking) of HA-coating on microporous silk scaffolds. The SEM observation showed that group with one cycle of alternate soaking (1C-HA) has the most optimal porosity like non-HA-modified microporous silk scaffolds. The proliferation of osteoblasts has no significant difference between noncoated HA (N-HA) and 1C-HA groups, which are both significantly higher than those in two cycles of soaking (2C-HA) and three cycles of soaking (3C-HA) groups. The transcription levels of specific genes (runx2 and osteonectin) in osteoblasts of 1C-HA group were significantly higher than those of N-HA group. Moreover, the levels showed no significant difference among 1C-HA, 2C-HA, and 3C-HA groups. In conclusion, microporous silk scaffold with 1 cycle of HA-coating can combine the biocompatibility of silk and osteogenicity of HA. Hongguo Li, Rui Zhu, Liguo Sun, Yingsen Xue, Zhangying Hao, Zhenghong Xie, Xiangli Fan, and Hongbin Fan Copyright © 2014 Hongguo Li et al. All rights reserved. Neuropeptide Substance P Improves Osteoblastic and Angiogenic Differentiation Capacity of Bone Marrow Stem Cells In Vitro Mon, 23 Jun 2014 08:51:00 +0000 Our previous work showed that implanting a sensory nerve or vascular bundle when constructing vascularized and neurotized bone could promote bone osteogenesis in tissue engineering. This phenomenon could be explained by the regulatory function of neuropeptides. Neuropeptide substance P (SP) has been demonstrated to contribute to bone growth by stimulating the proliferation and differentiation of bone marrow stem cells (BMSCs). However, there have been no prior studies on the association between Wnt signaling and the mechanism of SP in the context of BMSC differentiation. Our results have shown that SP could enhance the differentiation of BMSCs by activating gene and protein expression via the Wnt pathway and by translocating β-catenin, which can be inhibited by Wnt signaling blocker treatment or by the NK-1 antagonist. SP could also increase the growth factor level of bone morphogenetic protein-2 (BMP-2). Additionally, SP could enhance the migration ability of BMSCs, and the promotion of vascular endothelial growth factor (VEGF) expression by SP has been studied. In conclusion, SP could induce osteoblastic differentiation via the Wnt pathway and promote the angiogenic ability of BMSCs. These results indicate that a vascularized and neurotized tissue-engineered construct could be feasible for use in bone tissue engineering strategies. Su Fu, Gang Mei, Zhao Wang, Zhen-Lv Zou, Song Liu, Guo-Xian Pei, Long Bi, and Dan Jin Copyright © 2014 Su Fu et al. All rights reserved. Platelet-Rich Plasma in Bone Regeneration: Engineering the Delivery for Improved Clinical Efficacy Mon, 23 Jun 2014 08:18:39 +0000 Human bone is a tissue with a fairly remarkable inherent capacity for regeneration; however, this regenerative capacity has its limitations, and defects larger than a critical size lack the ability to spontaneously heal. As such, the development and clinical translation of effective bone regeneration modalities are paramount. One regenerative medicine approach that is beginning to gain momentum in the clinical setting is the use of platelet-rich plasma (PRP). PRP therapy is essentially a method for concentrating platelets and their intrinsic growth factors to stimulate and accelerate a healing response. While PRP has shown some efficacy in both in vitro and in vivo scenarios, to date its use and delivery have not been optimized for bone regeneration. Issues remain with the effective delivery of the platelet-derived growth factors to a localized site of injury, the activation and temporal release of the growth factors, and the rate of growth factor clearance. This review will briefly describe the physiological principles behind PRP use and then discuss how engineering its method of delivery may ultimately impact its ability to successfully translate to widespread clinical use. Isaac A. Rodriguez, Emily A. Growney Kalaf, Gary L. Bowlin, and Scott A. Sell Copyright © 2014 Isaac A. Rodriguez et al. All rights reserved. Shock Absorbing Function Study on Denucleated Intervertebral Disc with or without Hydrogel Injection through Static and Dynamic Biomechanical Tests In Vitro Sun, 22 Jun 2014 07:00:37 +0000 Hydrogel injection has been recently proposed as a novel therapy for disc degenerative diseases, with the potential to restore the spine motion and the intervertebral disc height. However, it remains unknown whether the new technique could also maintain the shock absorbing property of the treated intervertebral disc. In this study, 18 porcine lumbar bone-disc-bone specimens were collected and randomly divided into three groups: the normal with intact intervertebral discs, the mimic for the injection of disulfide cross-linked hyaluronan hydrogels following discectomy, and the control disc with discectomy only. In the static compression test, specimens in the mimic group exhibited displacements similar to those in the normal discs, whereas the control group showed a significantly larger displacement range in the first two steps (). With the frequency increasing, all specimens generally displayed an increasing storage modulus, decreasing loss modulus, and tanδ. At any frequency point, the control group exhibited the largest value in all the three parameters among three groups while the normal group was the lowest, with the mimic group being mostly close to the normal group. Therefore, the hydrogel injection into the intervertebral discs greatly restored their shock absorbing function, suggesting that the technique could serve as an effective approach to maintaining biomechanical properties of the degenerative intervertebral disc. Zhiyu Zhou, Manman Gao, Fuxin Wei, Jiabi Liang, Wenbin Deng, Xuejun Dai, Guangqian Zhou, and Xuenong Zou Copyright © 2014 Zhiyu Zhou et al. All rights reserved. Comparative Analysis of Proliferation and Differentiation Potentials of Stem Cells from Inflamed Pulp of Deciduous Teeth and Stem Cells from Exfoliated Deciduous Teeth Sun, 22 Jun 2014 00:00:00 +0000 Stem cells isolated from exfoliated deciduous teeth (SHEDs) are highly capable of proliferation and differentiation, and they represent good cell sources for mesenchymal stem cell- (MSC-) mediated dental tissue regeneration, but the supply of SHEDs is limited. A previous study found that stem cells could be isolated from inflamed tissues, but it is unknown whether primary dental pulp diagnosed with irreversible pulpitis might contain stem cells with appropriate tissue regeneration capacity. In this study, we aimed to isolate stem cells from both inflamed pulps of deciduous teeth (SCIDs) and SHEDs from Chinese children and to compare their proliferation and differentiation potentials. Our results showed that SCIDs were positive for cell surface markers, including CD105, CD90, and CD146, and they had high proliferation ability and osteogenic, adipogenic, and chondrogenic differentiation potentials. There was no significant difference in proliferation and differentiation potentials between SCIDs and SHEDs. The mRNA of inflammatory factors, including IL-1β, IL-6, and TNF-α, was expressed at similar levels in SCIDs and SHEDs, but SCIDs secreted more TNF-α protein. In conclusion, our in vitro results showed that SCIDs have proliferation and differentiation potentials similar to those of SHEDs. Thus, SCIDs represent a new potentially applicable source for MSC mediated tissue regeneration. Shi Yu, Shu Diao, Jinsong Wang, Gang Ding, Dongmei Yang, and Zhipeng Fan Copyright © 2014 Shi Yu et al. All rights reserved. Effects of Parathyroid Hormone on Calcium Ions in Rat Bone Marrow Mesenchymal Stem Cells Wed, 18 Jun 2014 09:38:33 +0000 The present study was conducted in order to explore the mechanisms whereby parathyroid hormone (PTH) maintains in vitro proliferation of bone marrow mesenchymal stem cells (BMSCs). Bone marrow was isolated from Sprague Dawley (SD) rat femurs, cultured in vitro, and passaged using a cell adherent culture method. The BMSC proliferation was evaluated by the methyl thiazolyl tetrazolium (MTT) assay and the fluorescence intensity of calcium ions in BMSCs was analyzed by laser scanning confocal microscopy (LSCM). Our results show that BMSC proliferation in the experimental group treated with PTH was more significant than controls. The calcium ion fluorescence intensity in BMSCs was significantly higher for the experimental group as compared to the control group. For each group, there was significant difference in the fluorescence intensity of calcium ions in BMSCs between 7 d and 14 d. In conclusion, parathyroid hormone increased the fluorescence intensity of calcium ions in BMSCs, which might represent a key mechanism whereby BMSC proliferation is maintained. Yushu Chen, Bo Bai, Shujiang Zhang, Jing Ye, Yi Chen, and Yanjun Zeng Copyright © 2014 Yushu Chen et al. All rights reserved. Construction and Biomechanical Properties of PolyAxial Self-Locking Anatomical Plate Based on the Geometry of Distal Tibia Mon, 16 Jun 2014 00:00:00 +0000 In order to provide scientific and empirical evidence for the clinical application of the polyaxial self-locking anatomical plate, 80 human tibias from healthy adults were scanned by spiral CT and their three-dimensional images were reconstructed using the surface shaded display (SSD) method. Firstly, based on the geometric data of distal tibia, a polyaxial self-locking anatomical plate for distal tibia was designed and constructed. Biomechanical tests were then performed by applying axial loading, 4-point bending, and axial torsion loading on the fracture fixation models of fresh cadaver tibias. Our results showed that variation in twisting angles of lateral tibia surface was found in various segments of the distal tibia. The polyaxial self-locking anatomical plate was constructed based on the geometry of the distal tibia. Compared to the conventional anatomical locking plate, the polyaxial self-locking anatomical plate of the distal tibia provides a better fit to the geometry of the distal tibia of the domestic population, and the insertion angle of locking screws can be regulated up to 30°. Collectively, this study assesses the geometry of the distal tibia and provides variable locking screw trajectory to improve screw-plate stability through the design of a polyaxial self-locking anatomical plate. Weiguo Liang, Weixiong Ye, Dongping Ye, Ziqiang Zhou, Zhiguang Chen, Aiguo Li, Zong-Han Xie, Lihai Zhang, and Jiake Xu Copyright © 2014 Weiguo Liang et al. All rights reserved. Chondrogenic Differentiation of Human Adipose-Derived Stem Cells: A New Path in Articular Cartilage Defect Management? Thu, 12 Jun 2014 09:26:57 +0000 According to data published by the Centers for Disease Control and Prevention, over 6 million people undergo a variety of medical procedures for the repair of articular cartilage defects in the U.S. each year. Trauma, tumor, and age-related degeneration can cause major defects in articular cartilage, which has a poor intrinsic capacity for healing. Therefore, there is substantial interest in the development of novel cartilage tissue engineering strategies to restore articular cartilage defects to a normal or prediseased state. Special attention has been paid to the expansion of chondrocytes, which produce and maintain the cartilaginous matrix in healthy cartilage. This review summarizes the current efforts to generate chondrocytes from adipose-derived stem cells (ASCs) and provides an outlook on promising future strategies. Jan-Philipp Stromps, Nora Emilie Paul, Björn Rath, Mahtab Nourbakhsh, Jürgen Bernhagen, and Norbert Pallua Copyright © 2014 Jan-Philipp Stromps et al. All rights reserved. Immobilized Lentivirus Vector on Chondroitin Sulfate-Hyaluronate Acid-Silk Fibroin Hybrid Scaffold for Tissue-Engineered Ligament-Bone Junction Thu, 12 Jun 2014 07:18:53 +0000 The lack of a fibrocartilage layer between graft and bone remains the leading cause of graft failure after anterior cruciate ligament (ACL) reconstruction. The objective of this study was to develop a gene-modified silk cable-reinforced chondroitin sulfate-hyaluronate acid-silk fibroin (CHS) hybrid scaffold for reconstructing the fibrocartilage layer. The scaffold was fabricated by lyophilizing the CHS mixture with braided silk cables. The scanning electronic microscopy (SEM) showed that microporous CHS sponges were formed around silk cables. Each end of scaffold was modified with lentiviral-mediated transforming growth factor-β3 (TGF-β3) gene. The cells on scaffold were transfected by bonded lentivirus. In vitro culture demonstrated that mesenchymal stem cells (MSCs) on scaffolds proliferated vigorously and produced abundant collagen. The transcription levels of cartilage-specific genes also increased with culture time. After 2 weeks, the MSCs were distributed uniformly throughout scaffold. Deposited collagen was also found to increase. The chondral differentiation of MSCs was verified by expressions of collagen II and TGF-β3 genes in mRNA and protein level. Histology also confirmed the production of cartilage extracellular matrix (ECM) components. The results demonstrated that gene-modified silk cable-reinforced CHS scaffold was capable of supporting cell proliferation and differentiation to reconstruct the cartilage layer of interface. Liguo Sun, Hongguo Li, Ling Qu, Rui Zhu, Xiangli Fan, Yingsen Xue, Zhenghong Xie, and Hongbin Fan Copyright © 2014 Liguo Sun et al. All rights reserved. Influence of Heating and Cyclic Tension on the Induction of Heat Shock Proteins and Bone-Related Proteins by MC3T3-E1 Cells Wed, 11 Jun 2014 11:29:41 +0000 Stress conditioning (e.g., thermal, shear, and tensile stress) of bone cells has been shown to enhance healing. However, prior studies have not investigated whether combined stress could synergistically promote bone regeneration. This study explored the impact of combined thermal and tensile stress on the induction of heat shock proteins (HSPs) and bone-related proteins by a murine preosteoblast cell line (MC3T3-E1). Cells were exposed to thermal stress using a water bath (44°C for 4 or 8 minutes) with postheating incubation (37°C for 4 hours) followed by exposure to cyclic strain (equibiaxial 3%, 0.2 Hz, cycle of 10-second tensile stress followed by 10-second rest). Combined thermal stress and tensile stress induced mRNA expression of HSP27 (1.41 relative fold induction (RFI) compared to sham-treated control), HSP70 (5.55 RFI), and osteopontin (1.44 RFI) but suppressed matrix metalloproteinase-9 (0.6 RFI) compared to the control. Combined thermal and tensile stress increased vascular endothelial growth factor (VEGF) secretion into the culture supernatant (1.54-fold increase compared to the control). Therefore, combined thermal and mechanical stress preconditioning can enhance HSP induction and influence protein expression important for bone tissue healing. Eunna Chung, Alana Cherrell Sampson, and Marissa Nichole Rylander Copyright © 2014 Eunna Chung et al. All rights reserved. ECM Inspired Coating of Embroidered 3D Scaffolds Enhances Calvaria Bone Regeneration Wed, 11 Jun 2014 09:05:37 +0000 Resorbable polymeric implants and surface coatings are an emerging technology to treat bone defects and increase bone formation. This approach is of special interest in anatomical regions like the calvaria since adults lose the capacity to heal large calvarial defects. The present study assesses the potential of extracellular matrix inspired, embroidered polycaprolactone-co-lactide (PCL) scaffolds for the treatment of 13 mm full thickness calvarial bone defects in rabbits. Moreover the influence of a collagen/chondroitin sulfate (coll I/cs) coating of PCL scaffolds was evaluated. Defect areas filled with autologous bone and empty defects served as reference. The healing process was monitored over 6 months by combining a novel ultrasonographic method, radiographic imaging, biomechanical testing, and histology. The PCL coll I/cs treated group reached 68% new bone volume compared to the autologous group (100%) and the biomechanical stability of the defect area was similar to that of the gold standard. Histological investigations revealed a significantly more homogenous bone distribution over the whole defect area in the PCL coll I/cs group compared to the noncoated group. The bioactive, coll I/cs coated, highly porous, 3-dimensional PCL scaffold acted as a guide rail for new skull bone formation along and into the implant. C. Rentsch, B. Rentsch, S. Heinemann, R. Bernhardt, B. Bischoff, Y. Förster, D. Scharnweber, and S. Rammelt Copyright © 2014 C. Rentsch et al. All rights reserved. Different Angiogenic Abilities of Self-Setting Calcium Phosphate Cement Scaffolds Consisting of Different Proportions of Fibrin Glue Tue, 10 Jun 2014 00:00:00 +0000 To investigate the different angiogenic abilities of the self-setting calcium phosphate cement (CPC) consisting of different proportions of fibrin glue (FG), the CPC powder and the FG solution were mixed at the powder/liquid (P/L) ratios of 1 : 0.5, 1 : 1, and 1 : 2 (g/mL), respectively, and pure CPC was used as a control. After being implanted into the lumbar dorsal fascia of the rabbit, the angiogenic process was evaluated by histological examination and CD31 immunohistochemistry to detect the new blood vessels. The result of the new blood vessel showed that the P/L ratio of 1 : 1 group indicated the largest quantity of new blood vessel at 4 weeks, 8 weeks, and 12 weeks after implantation, respectively. The histological evaluation also showed the best vascular morphology in the 1 : 1 group at 4 weeks, 8 weeks, and 12 weeks after the operation, respectively. Our study indicated that the CPC-FG composite scaffold at the P/L ratio of 1 : 1  (g/mL) stimulated angiopoiesis better than any other P/L ratios and has significant potential as the bioactive material for the treatment of bone defects. Jintao Xiu, Junjun Fan, Jie Li, Geng Cui, and Wei Lei Copyright © 2014 Jintao Xiu et al. All rights reserved. N-Isopropylacrylamide-co-glycidylmethacrylate as a Thermoresponsive Substrate for Corneal Endothelial Cell Sheet Engineering Mon, 09 Jun 2014 07:05:54 +0000 Endothelial keratoplasty is a recent shift in the surgical treatment of corneal endothelial dystrophies, where the dysfunctional endothelium is replaced whilst retaining the unaffected corneal layers. To overcome the limitation of donor corneal shortage, alternative use of tissue engineered constructs is being researched. Tissue constructs with intact extracellular matrix are generated using stimuli responsive polymers. In this study we evaluated the feasibility of using the thermoresponsive poly(N-isopropylacrylamide-co-glycidylmethacrylate) polymer as a culture surface to harvest viable corneal endothelial cell sheets. Incubation below the lower critical solution temperature of the polymer allowed the detachment of the intact endothelial cell sheet. Phase contrast and scanning electron microscopy revealed the intact architecture, cobble stone morphology, and cell-to-cell contact in the retrieved cell sheet. Strong extracellular matrix deposition was also observed. The RT-PCR analysis confirmed functionally active endothelial cells in the cell sheet as evidenced by the positive expression of aquaporin 1, collagen IV, Na+-K+ ATPase, and FLK-1. Na+-K+ ATPase protein expression was also visualized by immunofluorescence staining. These results suggest that the in-house developed thermoresponsive culture dish is a suitable substrate for the generation of intact corneal endothelial cell sheet towards transplantation for endothelial keratoplasty. Bernadette K. Madathil, Pallickaveedu RajanAsari Anil Kumar, and Thrikkovil Variyath Kumary Copyright © 2014 Bernadette K. Madathil et al. All rights reserved. Image-Based Three-Dimensional Analysis to Characterize the Texture of Porous Scaffolds Thu, 05 Jun 2014 11:10:33 +0000 The aim of the present study is to characterize the microstructure of composite scaffolds for bone tissue regeneration containing different ratios of chitosan/gelatin blend and bioactive glasses. Starting from realistic 3D models of the scaffolds reconstructed from micro-CT images, the level of heterogeneity of scaffold architecture is evaluated performing a lacunarity analysis. The results demonstrate that the presence of the bioactive glass component affects not only macroscopic features such as porosity, but mainly scaffold microarchitecture giving rise to structural heterogeneity, which could have an impact on the local cell-scaffold interaction and scaffold performances. The adopted approach allows to investigate the scale-dependent pore distribution within the scaffold and the related structural heterogeneity features, providing a comprehensive characterization of the scaffold texture. Diana Massai, Francesco Pennella, Piergiorgio Gentile, Diego Gallo, Gianluca Ciardelli, Cristina Bignardi, Alberto Audenino, and Umberto Morbiducci Copyright © 2014 Diana Massai et al. All rights reserved. Applications and Implications of Heparin and Protamine in Tissue Engineering and Regenerative Medicine Tue, 03 Jun 2014 09:23:16 +0000 Drug repositioning is one of the most rapidly emerging fields of study. This concept is anchored on the principle that diseases have similar damaged or affected signaling pathways. Recently, drugs have been repositioned not only for their alternative therapeutic uses but also for their applications as biomaterials in various fields. However, medical drugs as biomaterials are rarely focused on in reviews. Fragmin and protamine have been recently the sources of increasing attention in the field of tissue engineering and regenerative medicine. Fragmin and protamine have been manufactured primarily as a safe antidote for the circulating heparin. Lately, these drugs have been utilized as either micro- or nanoparticle biomaterials. In this paper, we will briefly describe the concept of drug repositioning and some of the medical drugs that have been repurposed for their alternative therapeutic uses. Also, this will feature the historical background of the studies focused on fragmin/protamine micro/nanoparticles (F/P M/NPs) and their applications as biomaterials in tissue engineering, stem cell therapy, and regenerative medicine. Judee Grace E. Nemeno, Soojung Lee, Wojong Yang, Kyung Mi Lee, and Jeong Ik Lee Copyright © 2014 Judee Grace E. Nemeno et al. All rights reserved. Experimental Study of Diffusion Coefficients of Water through the Collagen: Apatite Porosity in Human Trabecular Bone Tissue Wed, 21 May 2014 07:58:18 +0000 We firstly measured the swelling of single trabeculae from human femur heads during water imbibition. Since the swelling is caused by water diffusing from external surfaces to the core of the sample, by measuring the sample swelling over time, we obtained direct information about the transport of fluids through the intimate constituents of bone, where the mineralization process takes place. We developed an apparatus to measure the free expansion of the tissue during the imbibition. In particular, we measured the swelling along three natural axes (length L, width W, and thickness T) of plate-like trabeculae. For this aim, we developed a 3D analytical model of the water uptake by the sample that was performed according to Fickian transport mechanism. The results were then utilized to predict the swelling over time along the three sample directions (L, W, T) and the apparent diffusion coefficients DT, DW, and DL. Franco Marinozzi, Fabiano Bini, Alessandro Quintino, Massimo Corcione, and Andrea Marinozzi Copyright © 2014 Franco Marinozzi et al. All rights reserved. Effect of Nonviral Plasmid Delivered Basic Fibroblast Growth Factor and Low Intensity Pulsed Ultrasound on Mandibular Condylar Growth: A Preliminary Study Tue, 20 May 2014 08:00:22 +0000 Objective. Basic fibroblast growth factor (bFGF) is an important regulator of tissue growth. Previous studies have shown that low intensity pulsed ultrasound (LIPUS) stimulates bone growth. The objective of this study was to evaluate the possible synergetic effect of LIPUS and local injection of nonviral bFGF plasmid DNA (pDNA) on mandibular growth in rats. Design. Groups were control, blank pDNA, bFGF pDNA, LIPUS, and bFGF pDNA + LIPUS. Treatments were performed for 28 days. Significant increase was observed in mandibular height and condylar length in LIPUS groups. MicroCT analysis showed significant increase in bone volume fraction in bFGF pDNA + LIPUS group. Histomorphometric analysis showed increased cell count and condylar proliferative and hypertrophic layers widths in bFGF pDNA group. Results. Current study showed increased mandibular condylar growth in either bFGF pDNA or LIPUS groups compared to the combined group that showed only increased bone volume fraction. Conclusion. It appears that there is an additive effect of bFGF + LIPUS on the mandibular growth. Harmanpreet Kaur, Hasan Uludağ, and Tarek El-Bialy Copyright © 2014 Harmanpreet Kaur et al. All rights reserved. Gene Modification of Mesenchymal Stem Cells and Articular Chondrocytes to Enhance Chondrogenesis Mon, 19 May 2014 13:13:35 +0000 Current cell based treatment for articular cartilage and osteochondral defects are hampered by issues such as cellular dedifferentiation and hypertrophy of the resident or transplanted cells. The reduced expression of chondrogenic signalling molecules and transcription factors is a major contributing factor to changes in cell phenotype. Gene modification of chondrocytes may be one approach to redirect cells to their primary phenotype and recent advances in nonviral and viral gene delivery technologies have enabled the expression of these lost factors at high efficiency and specificity to regain chondrocyte function. This review focuses on the various candidate genes that encode signalling molecules and transcription factors that are specific for the enhancement of the chondrogenic phenotype and also how epigenetic regulators of chondrogenesis in the form of microRNA may also play an important role. Saliya Gurusinghe and Padraig Strappe Copyright © 2014 Saliya Gurusinghe and Padraig Strappe. All rights reserved. The ECM-Cell Interaction of Cartilage Extracellular Matrix on Chondrocytes Sun, 18 May 2014 11:10:01 +0000 Cartilage extracellular matrix (ECM) is composed primarily of the network type II collagen (COLII) and an interlocking mesh of fibrous proteins and proteoglycans (PGs), hyaluronic acid (HA), and chondroitin sulfate (CS). Articular cartilage ECM plays a crucial role in regulating chondrocyte metabolism and functions, such as organized cytoskeleton through integrin-mediated signaling via cell-matrix interaction. Cell signaling through integrins regulates several chondrocyte functions, including differentiation, metabolism, matrix remodeling, responses to mechanical stimulation, and cell survival. The major signaling pathways that regulate chondrogenesis have been identified as wnt signal, nitric oxide (NO) signal, protein kinase C (PKC), and retinoic acid (RA) signal. Integrins are a large family of molecules that are central regulators in multicellular biology. They orchestrate cell-cell and cell-matrix adhesive interactions from embryonic development to mature tissue function. In this review, we emphasize the signaling molecule effect and the biomechanics effect of cartilage ECM on chondrogenesis. Yue Gao, Shuyun Liu, Jingxiang Huang, Weimin Guo, Jifeng Chen, Li Zhang, Bin Zhao, Jiang Peng, Aiyuan Wang, Yu Wang, Wenjing Xu, Shibi Lu, Mei Yuan, and Quanyi Guo Copyright © 2014 Yue Gao et al. All rights reserved. Extracellular Matrix Modulates Angiogenesis in Physiological and Pathological Conditions Sun, 18 May 2014 10:26:41 +0000 Angiogenesis is a multistep process driven by a wide range of positive and negative regulatory factors. Extracellular matrix (ECM) plays a crucial role in the regulation of this process. The degradation of ECM, occurring in response to an angiogenic stimulus, leads to degradation or partial modification of matrix molecules, release of soluble factors, and exposure of cryptic sites with pro- and/or antiangiogenic activity. ECM molecules and fragments, resulting from proteolysis, can also act directly as inflammatory stimuli, and this can explain the exacerbated angiogenesis that drives and maintains several inflammatory diseases. In this review we have summarized some of the more recent literature data concerning the molecular control of ECM in angiogenesis in both physiological and pathological conditions. Anna Neve, Francesco Paolo Cantatore, Nicola Maruotti, Addolorata Corrado, and Domenico Ribatti Copyright © 2014 Anna Neve et al. All rights reserved. Novel Scaffolds Fabricated Using Oleuropein for Bone Tissue Engineering Tue, 13 May 2014 09:13:09 +0000 We investigated the feasibility of oleuropein as a cross-linking agent for fabricating three-dimensional (3D) porous composite scaffolds for bone tissue engineering. Human-like collagen (HLC) and nanohydroxyapatite (n-HAp) were used to fabricate the composite scaffold by way of cross-linking. The mechanical tests revealed superior properties for the cross-linked scaffolds compared to the uncross-linked scaffolds. The as-obtained composite scaffold had a 3D porous structure with pores ranging from 120 to 300 μm and a porosity of %. The cross-linked scaffolds were seeded with MC3T3-E1 Subclone 14 mouse osteoblasts. Fluorescence staining, the Cell Counting Kit-8 (CCK-8) assay, and scanning electron microscopy (SEM) indicated that the scaffolds enhanced cell adhesion and proliferation. Our results indicate the potential of these scaffolds for bone tissue engineering. Hui Fan, Junfeng Hui, Zhiguang Duan, Daidi Fan, Yu Mi, Jianjun Deng, and Hui Li Copyright © 2014 Hui Fan et al. All rights reserved. Microsurgical Techniques Used to Construct the Vascularized and Neurotized Tissue Engineered Bone Tue, 13 May 2014 00:00:00 +0000 The lack of vascularization in the tissue engineered bone results in poor survival and ossification. Tissue engineered bone can be wrapped in the soft tissue flaps which are rich in blood supply to complete the vascularization in vivo by microsurgical technique, and the surface of the bone graft can be invaded with new vascular network. The intrinsic vascularization can be induced via a blood vessel or an arteriovenous loop located centrally in the bone graft by microsurgical technique. The peripheral nerve especially peptidergic nerve has effect on the bone regeneration. The peptidergic nerve can be used to construct the neurotized tissue engineered bone by implanting the nerve fiber into the center of bone graft. Thus, constructing a highly vascularized and neurotized tissue engineered bone according with the theory of biomimetics has become a useful method for repairing the large bone defect. Many researchers have used the microsurgical techniques to enhance the vascularization and neurotization of tissue engineered bone and to get a better osteogenesis effect. This review aims to summarize the microsurgical techniques mostly used to construct the vascularized and neurotized tissue engineered bone. Junjun Fan, Long Bi, Dan Jin, Kuanhai Wei, Bin Chen, Zhiyong Zhang, and Guoxian Pei Copyright © 2014 Junjun Fan et al. All rights reserved. Synthesis and Characterization of Poly(lactic-co-glycolic) Acid Nanoparticles-Loaded Chitosan/Bioactive Glass Scaffolds as a Localized Delivery System in the Bone Defects Sun, 11 May 2014 11:42:22 +0000 The functionality of tissue engineering scaffolds can be enhanced by localized delivery of appropriate biological macromolecules incorporated within biodegradable nanoparticles. In this research, chitosan/58S-bioactive glass (58S-BG) containing poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been prepared and then characterized. The effects of further addition of 58S-BG on the structure of scaffolds have been investigated to optimize the characteristics of the scaffolds for bone tissue engineering applications. The results showed that the scaffolds had high porosity with open pores. It was also shown that the porosity decreased with increasing 58S-BG content. Furthermore, the PLGA nanoparticles were homogenously distributed within the scaffolds. According to the obtained results, the nanocomposites could be considered as highly bioactive bone tissue engineering scaffolds with the potential of localized delivery of biological macromolecules. K. Nazemi, F. Moztarzadeh, N. Jalali, S. Asgari, and M. Mozafari Copyright © 2014 K. Nazemi et al. All rights reserved. Perilipin Expression Reveals Adipogenic Potential of hADSCs inside Superporous Polymeric Cellular Delivery Systems Sun, 04 May 2014 14:03:06 +0000 Recent progress in tissue engineering and regenerative medicine envisages the use of cell-scaffold bioconstructs to best mimic the natural in vivo microenvironment. Our aim was not only to develop novel 3D porous scaffolds for regenerative applications by the association of gelatin (G), alginate (A), and polyacrylamide (PAA) major assets but also to evaluate their in vitro potential to support human adipose-derived stem cells (hADSCs) adipogenesis. G-A-PAA biomatrix investigated in this work is an interesting substrate combining the advantages of the three individual constituents, namely, biodegradability of G, hydrophilicity of A and PAA, superior elasticity at compression with respect to the G-A and PAA controls, and the capacity to generate porous scaffolds. hADSCs inside these novel interpenetrating polymer networks (IPNs) were able to populate the entire scaffold structure and to display their characteristic spindle-like shape as a consequence of a good interaction with G component of the matrices. Additionally, hADSCs proved to display the capacity to differentiate towards mature adipocytes, to accumulate lipids inside their cytoplasm, and to express perilipin late adipogenic marker inside novel IPNs described in this study. On long term, this newly designed biomatrix aims to represent a stem cell delivery system product dedicated for modern regenerative strategies. Sorina Dinescu, Bianca Galateanu, Adriana Lungu, Eugen Radu, Sorin Nae, Horia Iovu, and Marieta Costache Copyright © 2014 Sorina Dinescu et al. All rights reserved. Cartilage Repair Surgery: Outcome Evaluation by Using Noninvasive Cartilage Biomarkers Based on Quantitative MRI Techniques? Sun, 04 May 2014 00:00:00 +0000 Background. New quantitative magnetic resonance imaging (MRI) techniques are increasingly applied as outcome measures after cartilage repair. Objective. To review the current literature on the use of quantitative MRI biomarkers for evaluation of cartilage repair at the knee and ankle. Methods. Using PubMed literature research, studies on biochemical, quantitative MR imaging of cartilage repair were identified and reviewed. Results. Quantitative MR biomarkers detect early degeneration of articular cartilage, mainly represented by an increasing water content, collagen disruption, and proteoglycan loss. Recently, feasibility of biochemical MR imaging of cartilage repair tissue and surrounding cartilage was demonstrated. Ultrastructural properties of the tissue after different repair procedures resulted in differences in imaging characteristics. T2 mapping, T1rho mapping, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), and diffusion weighted imaging (DWI) are applicable on most clinical 1.5 T and 3 T MR scanners. Currently, a standard of reference is difficult to define and knowledge is limited concerning correlation of clinical and MR findings. The lack of histological correlations complicates the identification of the exact tissue composition. Conclusions. A multimodal approach combining several quantitative MRI techniques in addition to morphological and clinical evaluation might be promising. Further investigations are required to demonstrate the potential for outcome evaluation after cartilage repair. Pia M. Jungmann, Thomas Baum, Jan S. Bauer, Dimitrios C. Karampinos, Benjamin Erdle, Thomas M. Link, Xiaojuan Li, Siegfried Trattnig, Ernst J. Rummeny, Klaus Woertler, and Goetz H. Welsch Copyright © 2014 Pia M. Jungmann et al. All rights reserved. Development and Retranslational Validation of an In Vitro Model to Characterize Acute Infections in Large Human Joints Wed, 30 Apr 2014 14:04:46 +0000 Bacterial infections can destroy cartilage integrity, resulting in osteoarthritis. Goal was to develop an in vitro model with in vivo validation of acute joint inflammation. Inflammation in cocultivated human synovial fibroblasts (SFB), chondrocytes (CHDR), and mononuclear cells (MNC) was successively relieved for 10 days. Articular effusions from patients with () and without () postoperative joint infection in healthy patients (ASA 1-2) were used as model validation. Inflammation in vitro resulted in an enormous increase in IL-1 and a successive reduction in SFB numbers. CHDR however, maintained metabolic activity and proteoglycan synthesis. While concentrations of bFGF in vivo and in vitro rose consistently, the mRNA increase was only moderate. Concurring with our in vivo data, cartilage-specific IGF-1 steadily increased, while IGF-1 mRNA in the CHDR and SFB did not correlate with protein levels. Similarly, aggrecan (ACAN) protein concentrations increased in vivo and failed to correlate in vitro with gene expression in either the CHDR or the SFB, indicating extracellular matrix breakdown. Anabolic cartilage-specific BMP-7 with highly significant intra-articular levels was significantly elevated in vitro on day 10 following maximum inflammation. Our in vitro model enables us to validate early inflammation of in vivo cell- and cytokine-specific regulatory patterns. This trial is registered with MISSinG, DRKS 00003536. Ingo H. Pilz, Alexander Mehlhorn, David Dovi-Akue, Elia Raoul Langenmair, Norbert P. Südkamp, and Hagen Schmal Copyright © 2014 Ingo H. Pilz et al. All rights reserved. Biodegradable Polyphosphazene Biomaterials for Tissue Engineering and Delivery of Therapeutics Tue, 29 Apr 2014 11:59:10 +0000 Degradable biomaterials continue to play a major role in tissue engineering and regenerative medicine as well as for delivering therapeutic agents. Although the chemistry of polyphosphazenes has been studied extensively, a systematic review of their applications for a wide range of biomedical applications is lacking. Polyphosphazenes are synthesized through a relatively well-known two-step reaction scheme which involves the substitution of the initial linear precursor with a wide range of nucleophiles. The ease of substitution has led to the development of a broad class of materials that have been studied for numerous biomedical applications including as scaffold materials for tissue engineering and regenerative medicine. The objective of this review is to discuss the suitability of poly(amino acid ester)phosphazene biomaterials in regard to their unique stimuli responsive properties, tunable degradation rates and mechanical properties, as well as in vitro and in vivo biocompatibility. The application of these materials in areas such as tissue engineering and drug delivery is discussed systematically. Lastly, the utility of polyphosphazenes is further extended as they are being employed in blend materials for new applications and as another method of tailoring material properties. Amanda L. Baillargeon and Kibret Mequanint Copyright © 2014 Amanda L. Baillargeon and Kibret Mequanint. All rights reserved. Human Periodontal Ligament Derived Progenitor Cells: Effect of STRO-1 Cell Sorting and Wnt3a Treatment on Cell Behavior Mon, 28 Apr 2014 06:57:01 +0000 Objectives. STRO-1 positive periodontal ligament cells (PDLCs) and unsorted PDLCs have demonstrated potential for periodontal regeneration, but the comparison between unsorted cells and the expanded STRO-1 sorted cells has never been reported. Additionally, Wnt3a is involved in cell proliferation thus may benefit in vitro PDLC expansion. The aim was to evaluate the effect of STRO-1 cell sorting and Wnt3a treatment on cell behavior of human PDLCs (hPDLCs). Materials and Methods. STRO-1 positive hPDLCs were sorted and the sorted cells were expanded and compared with their unsorted parental cells. Thereafter, hPDLCs were treated with or without Wnt3a and the cell proliferation, self-renewal, and osteogenic differentiation were evaluated. Results. No differences were measured between the expanded STRO-1-sorted cells and unsorted parental cells in terms of proliferation, CFU, and mineralization capacity. Wnt3a enhanced the proliferation and self-renewal ability of hPDLCs significantly as displayed by higher DNA content values, a shorter cell population doubling time, and higher expression of the self-renewal gene Oct4. Moreover, Wnt3a promoted the expansion of hPDLCs for 5 passages without affecting cell proliferation, CFU, and osteogenic capacity. Conclusions. Expanded STRO-1-sorted hPDLCs showed no superiority compared to their unsorted parental cells. On the other hand, Wnt3a promotes the efficient hPDLC expansion and retains the self-renewal and osteogenic differentiation capacity. Xiang-Zhen Yan, Sanne K. Both, Pi-Shan Yang, John A. Jansen, Jeroen J. J. P. van den Beucken, and Fang Yang Copyright © 2014 Xiang-Zhen Yan et al. All rights reserved. Exogenous IL-4-Expressing Bone Marrow Mesenchymal Stem Cells for the Treatment of Autoimmune Sensorineural Hearing Loss in a Guinea Pig Model Tue, 22 Apr 2014 14:02:33 +0000 Bone marrow mesenchymal stem cells (BMSCs) expressing recombinant IL-4 have the potential to remediate inflammatory diseases. We thus investigated whether BMSCs expressing exogenous IL-4 could alleviate autoimmune sensorineural hearing loss. BMSCs isolated from guinea pigs were transfected with recombinant lentivirus expressing IL-4. A total of 33 animals were divided into three groups. Group A received scala tympani injection of IL-4-expressing BMSCs, and Group B received control vector-expressing BMSCs, and Group C received phosphate-buffered saline. The distribution of implanted BMSCs in the inner ears was assessed by immunohistochemistry and fluorescence microscopy. Auditory brain-stem response (ABR) was monitored to evaluate the auditory changes. Following BMSCs transplantation, the threshold levels of ABR wave III decreased in Groups A and B and significant differences were observed between these two groups . Transplanted BMSCs distributed in the scala tympani and scala vestibuli. In some ears with hearing loss, there was a decrease in the number of spiral ganglion cells and varying degrees of endolymphatic hydrops or floccule. Following transplantation, the lentivirus-infected BMSCs migrated to the inner ear and produced IL-4. Our results demonstrate that, upon transplantation, BMSCs and BMSCs expressing recombinant IL-4 have the ability to remediate the inflammatory injury in autoimmune inner ear diseases. Chang-qiang Tan, Xia Gao, Lang Guo, and He Huang Copyright © 2014 Chang-qiang Tan et al. All rights reserved. The Study of the Frequency Effect of Dynamic Compressive Loading on Primary Articular Chondrocyte Functions Using a Microcell Culture System Wed, 16 Apr 2014 07:15:41 +0000 Compressive stimulation can modulate articular chondrocyte functions. Nevertheless, the relevant studies are not comprehensive. This is primarily due to the lack of cell culture apparatuses capable of conducting the experiments in a high throughput, precise, and cost-effective manner. To address the issue, we demonstrated the use of a perfusion microcell culture system to investigate the stimulating frequency (0.5, 1.0, and 2.0 Hz) effect of compressive loading (20% and 40% strain) on the functions of articular chondrocytes. The system mainly integrates the functions of continuous culture medium perfusion and the generation of pneumatically-driven compressive stimulation in a high-throughput micro cell culture system. Results showed that the compressive stimulations explored did not have a significant impact on chondrocyte viability and proliferation. However, the metabolic activity of chondrocytes was significantly affected by the stimulating frequency at the higher compressive strain of 40% (2 Hz, 40% strain). Under the two compressive strains studied, the glycosaminoglycans (GAGs) synthesis was upregulated when the stimulating frequency was set at 1 Hz and 2 Hz. However, the stimulating frequencies explored had no influence on the collagen production. The results of this study provide useful fundamental insights that will be helpful for cartilage tissue engineering and cartilage rehabilitation. Wan-Ying Lin, Yu-Han Chang, Hsin-Yao Wang, Tzu-Chi Yang, Tzu-Keng Chiu, Song-Bin Huang, and Min-Hsien Wu Copyright © 2014 Wan-Ying Lin et al. All rights reserved. The Pilot Study of Fibrin with Temporomandibular Joint Derived Synovial Stem Cells in Repairing TMJ Disc Perforation Tue, 15 Apr 2014 13:12:10 +0000 TMJ disc related diseases are difficult to be cured due to the poor repair ability of the disc. TMJ-SDSCs were ideal cell sources for cartilage tissue engineering which have been widely used in hyaline cartilage regeneration. Fibrin gel has been demonstrated as a potential scaffold for neocartilage formation. The aim of this study was to repair the TMJ disc perforation using fibrin/chitosan hybrid scaffold combined with TMJ-SDSCs. Rat TMJ-SDSCs were cultured on hybrid scaffold or pure chitosan scaffolds. The cell seeding efficiency, distribution, proliferation, and chondrogenic differentiation capacity were investigated. To evaluate the in vivo repair ability of cell/scaffold construct, rat TMJ disc explants were punched with a defect to mimic TMJ disc perforation. Cell seeded scaffolds were inserted into the defect of TMJ disc explants and then were implanted subcutaneously in nude mice for 4 weeks. Results demonstrated that fibrin may improve cell seeding, proliferation, and chondrogenic induction in vitro. The in vivo experiments showed more cartilage ECM deposition in fibrin/chitosan scaffold, which suggested an enhanced reparative ability. This pilot study demonstrated that the regenerative ability of TMJ-SDSCs seeded in fibrin/chitosan scaffold could be applied for repairing TMJ disc perforation. Yang Wu, Zhongcheng Gong, Jian Li, Qinggong Meng, Wei Fang, and Xing Long Copyright © 2014 Yang Wu et al. All rights reserved. Generation of Insulin-Producing Cells from Human Bone Marrow-Derived Mesenchymal Stem Cells: Comparison of Three Differentiation Protocols Thu, 10 Apr 2014 11:14:48 +0000 Introduction. Many protocols were utilized for directed differentiation of mesenchymal stem cells (MSCs) to form insulin-producing cells (IPCs). We compared the relative efficiency of three differentiation protocols. Methods. Human bone marrow-derived MSCs (HBM-MSCs) were obtained from three insulin-dependent type 2 diabetic patients. Differentiation into IPCs was carried out by three protocols: conophylline-based (one-step protocol), trichostatin-A-based (two-step protocol), and β-mercaptoethanol-based (three-step protocol). At the end of differentiation, cells were evaluated by immunolabeling for insulin production, expression of pancreatic endocrine genes, and release of insulin and c-peptide in response to increasing glucose concentrations. Results. By immunolabeling, the proportion of generated IPCs was modest (≃3%) in all the three protocols. All relevant pancreatic endocrine genes, insulin, glucagon, and somatostatin, were expressed. There was a stepwise increase in insulin and c-peptide release in response to glucose challenge, but the released amounts were low when compared with those of pancreatic islets. Conclusion. The yield of functional IPCs following directed differentiation of HBM-MSCs was modest and was comparable among the three tested protocols. Protocols for directed differentiation of MSCs need further optimization in order to be clinically meaningful. To this end, addition of an extracellular matrix and/or a suitable template should be attempted. Mahmoud M. Gabr, Mahmoud M. Zakaria, Ayman F. Refaie, Sherry M. Khater, Sylvia A. Ashamallah, Amani M. Ismail, Nagwa El-Badri, and Mohamed A. Ghoneim Copyright © 2014 Mahmoud M. Gabr et al. All rights reserved. Evaluation of Insulin Medium or Chondrogenic Medium on Proliferation and Chondrogenesis of ATDC5 Cells Thu, 10 Apr 2014 09:09:17 +0000 Background. The ATDC5 cell line is regarded as an excellent cell model for chondrogenesis. In most studies with ATDC5 cells, insulin medium (IM) was used to induce chondrogenesis while chondrogenic medium (CM), which was usually applied in chondrogenesis of mesenchymal stem cells (MSCs), was rarely used for ATDC5 cells. This study was mainly designed to investigate the effect of IM, CM, and growth medium (GM) on chondrogenesis of ATDC5 cells. Methods. ATDC5 cells were, respectively, cultured in IM, CM, and GM for a certain time. Then the proliferation and the chondrogenesis progress of cells in these groups were analyzed. Results. Compared with CM and GM, IM promoted the proliferation of cells significantly. CM was effective for enhancement of cartilage specific markers, while IM induced the cells to express endochondral ossification related genes. Although GAG deposition per cell in CM group was significantly higher than that in IM and GM groups, the total GAG contents in IM group were the most. Conclusion. This study demonstrated that CM focused on induction of chondrogenic differentiation while IM was in favor of promoting proliferation and expression of endochondral ossification related genes. Combinational use of these two media would be more beneficial to bone/cartilage repair. Yongchang Yao, Zhichen Zhai, and Yingjun Wang Copyright © 2014 Yongchang Yao et al. All rights reserved. Enhanced Osteogenicity of Bioactive Composites with Biomimetic Treatment Wed, 09 Apr 2014 07:12:59 +0000 Purpose. This study aimed to explore if initiation of biomimetic apatite nucleation can be used to enhance osteoblast response to biodegradable tissue regeneration composite membranes. Materials and Methods. Bioactive thermoplastic composites consisting of poly(ε-caprolactone/DL-lactide) and bioactive glass (BAG) were prepared at different stages of biomimetic calcium phosphate deposition by immersion in simulated body fluid (SBF). The modulation of the BAG dissolution and the osteogenic response of rat mesenchymal stem cells (MSCs) were analyzed. Results. SBF treatment resulted in a gradual calcium phosphate deposition on the composites and decreased BAG reactivity in the subsequent cell cultures. Untreated composites and composites covered by thick calcium phosphate layer (14 days in SBF) expedited MSC mineralization in comparison to neat polymers without BAG, whereas other osteogenic markers—alkaline phosphatase activity, bone sialoprotein, and osteocalcin expression—were initially decreased. In contrast, surfaces with only small calcium phosphate aggregates (five days in SBF) had similar early response than neat polymers but still demonstrated enhanced mineralization. Conclusion. A short biomimetic treatment enhances osteoblast response to bioactive composite membranes. Ville V. Meretoja, Teemu Tirri, Minna Malin, Jukka V. Seppälä, and Timo O. Närhi Copyright © 2014 Ville V. Meretoja et al. All rights reserved. Effect of Cyclic Mechanical Stimulation on the Expression of Osteogenesis Genes in Human Intraoral Mesenchymal Stromal and Progenitor Cells Mon, 07 Apr 2014 07:12:18 +0000 We evaluated the effects of mechanical stimulation on the osteogenic differentiation of human intraoral mesenchymal stem and progenitor cells (MSPCs) using the Flexcell FX5K Tension System that mediated cyclic tensile stretch on the cells. MSPCs were isolated from human mandibular retromolar bones and characterized using flow cytometry. The positive expression of CD73, CD90, and CD105 and negativity for CD14, CD19, CD34, CD45, and HLA-DR confirmed the MSPC phenotype. Mean MSPC doubling time was  hrs. The percentage of lactate dehydrogenase (LDH) release showed no significant difference between the mechanically stimulated groups and the unstimulated controls. Reverse transcription quantitative real-time PCR revealed that 10% continuous cyclic strain (0.5 Hz) for 7 and 14 days induced a significant increase in the mRNA expression of the osteogenesis-specific markers type-I collagen (Col1A1), osteonectin (SPARC), bone morphogenetic protein 2 (BMP2), osteopontin (SPP1), and osteocalcin (BGLAP) in osteogenic differentiated MSPCs. Furthermore, mechanically stimulated groups produced significantly higher amounts of calcium deposited into the cultures and alkaline phosphatase (ALP). These results will contribute to a better understanding of strain-induced bone remodelling and will form the basis for the correct choice of applied force in oral and maxillofacial surgery. Birgit Lohberger, Heike Kaltenegger, Nicole Stuendl, Michael Payer, Beate Rinner, and Andreas Leithner Copyright © 2014 Birgit Lohberger et al. All rights reserved. Current Trends in Bone Tissue Engineering Sun, 06 Apr 2014 12:21:10 +0000 The development of tissue engineering and regeneration constitutes a new platform for translational medical research. Effective therapies for bone engineering typically employ the coordinated manipulation of cells, biologically active signaling molecules, and biomimetic, biodegradable scaffolds. Bone tissue engineering has become increasingly dependent on the merging of innovations from each of these fields, as they continue to evolve independently. This foreword will highlight some of the most recent advances in bone tissue engineering and regeneration, emphasizing the interconnected fields of stem cell biology, cell signaling biology, and biomaterial research. These include, for example, novel methods for mesenchymal stem cell purification, new methods of Wnt signaling pathway manipulation, and cutting edge computer assisted nanoscale design of bone scaffold materials. In the following special issue, we sought to incorporate these diverse areas of emphasis in order to reflect current trends in the field. Marco Mravic, Bruno Péault, and Aaron W. James Copyright © 2014 Marco Mravic et al. All rights reserved. Expressions of ABCG2, CD133, and Podoplanin in Salivary Adenoid Cystic Carcinoma Sun, 06 Apr 2014 11:28:47 +0000 Adenoid cystic carcinoma (ACC) is one of the most common salivary gland malignant tumors with a high risk of recurrence and metastasis. Current studies on cancer stem cells (CSCs) have verified that CSCs are the driving force behind tumor initiation and progression, suggesting that new cancer therapies may be established by effectively targeting and killing the CSCs. The primary goal of this study is to investigate the expression patterns of ABCG2, CD133, and podoplanin in ACC of minor salivary glands by immunohistochemistry analysis. We found that ABCG2 was weakly expressed in normal looking salivary gland tissues. A significant upregulation of ABCG2 expression in ACC was observed with a similar expression pattern of Ki-67. CD133 was detected in apical membrane of epithelial cells and podoplanin was expressed positively in myoepithelial cells of both normal looking tissue and ACC. However, no significant difference was found of the expression pattern of CD133 and podoplanin between normal looking tissues and ACC. Our observations suggest that CSCs may exist in quiescent cells with ABCG2 positive staining, which are surrounded by cells with positive expression of ABCG2 and Ki-67 in ACC, and costaining with ABCG2 and Ki-67 may help predict the location of CSCs. Wuwei Li, Ryo Tamamura, Bo Wang, Qigui Liu, Han Liu, Tingjiao Liu, Naoki Katase, Jing Xiao, and Hitoshi Nagatsuka Copyright © 2014 Wuwei Li et al. All rights reserved. Deregulation of Bone Forming Cells in Bone Diseases and Anabolic Effects of Strontium-Containing Agents and Biomaterials Mon, 31 Mar 2014 15:17:17 +0000 Age-related bone loss and osteoporosis are associated with bone remodeling changes that are featured with decreased trabecular and periosteal bone formation relative to bone resorption. Current anticatabolic therapies focusing on the inhibition of bone resorption may not be sufficient in the prevention or reversal of age-related bone deterioration and there is a big need in promoting osteoblastogenesis and bone formation. Enhanced understanding of the network formed by key signaling pathways and molecules regulating bone forming cells in health and diseases has therefore become highly significant. The successful development of agonist/antagonist of the PTH and Wnt signaling pathways are profits of the understanding of these key pathways. As the core component of an approved antiosteoporosis agent, strontium takes its effect on osteoblasts at multilevel through multiple pathways, representing a good example in revealing and exploring anabolic mechanisms. The recognition of strontium effects on bone has led to its expected application in a variety of biomaterial scaffolds used in tissue engineering strategies aiming at bone repairing and regeneration. While summarizing the recent progress in these respects, this review also proposes the new approaches such as systems biology in order to reveal new insights in the pathology of osteoporosis as well as possible discovery of new therapies. Shuang Tan, Binbin Zhang, Xiaomei Zhu, Ping Ao, Huajie Guo, Weihong Yi, and Guang-Qian Zhou Copyright © 2014 Shuang Tan et al. All rights reserved. Characterization of Silk Fibroin Modified Surface: A Proteomic View of Cellular Response Proteins Induced by Biomaterials Tue, 25 Mar 2014 13:30:48 +0000 The purpose of this study was to develop the pathway of silk fibroin (SF) biopolymer surface induced cell membrane protein activation. Fibroblasts were used as an experimental model to evaluate the responses of cellular proteins induced by biopolymer material using a mass spectrometry-based profiling system. The surface was covered by multiwalled carbon nanotubes (CNTs) and SF to increase the surface area, enhance the adhesion of biopolymer, and promote the rate of cell proliferation. The amount of adhered fibroblasts on CNTs/SF electrodes of quartz crystal microbalance (QCM) greatly exceeded those on other surfaces. Moreover, analyzing differential protein expressions of adhered fibroblasts on the biopolymer surface by proteomic approaches indicated that CD44 may be a key protein. Through this study, utilization of mass spectrometry-based proteomics in evaluation of cell adhesion on biopolymer was proposed. Ming-Hui Yang, Shyng-Shiou Yuan, Tze-Wen Chung, Shiang-Bin Jong, Chi-Yu Lu, Wan-Chi Tsai, Wen-Cheng Chen, Po-Chiao Lin, Pei-Wen Chiang, and Yu-Chang Tyan Copyright © 2014 Ming-Hui Yang et al. All rights reserved. Adipose-Derived Mesenchymal Stem Cells from Ventral Hernia Repair Patients Demonstrate Decreased Vasculogenesis Mon, 17 Mar 2014 08:40:41 +0000 Introduction. In adipose tissue healing, angiogenesis is stimulated by adipose-derived stromal stem cells (ASCs). Ventral hernia repair (VHR) patients are at high risk for wound infections. We hypothesize that ASCs from VHR patients are less vasculogenic than ASCs from healthy controls. Methods. ASCs were harvested from the subcutaneous fat of patients undergoing VHR by the component separation technique and from matched abdominoplasty patients. RNA and protein were harvested on culture days 0 and 3. Both groups of ASCs were subjected to hypoxic conditions for 12 and 24 hours. RNA was analyzed using qRT-PCR, and protein was used for western blotting. ASCs were also grown in Matrigel under hypoxic conditions and assayed for tubule formation after 24 hours. Results. Hernia patient ASCs demonstrated decreased levels of VEGF-A protein and vasculogenic RNA at 3 days of growth in differentiation media. There were also decreases in VEGF-A protein and vasculogenic RNA after growth in hypoxic conditions compared to control ASCs. After 24 hours in hypoxia, VHR ASCs formed fewer tubules in Matrigel than in control patient ASCs. Conclusion. ASCs derived from VHR patients appear to express fewer vasculogenic markers and form fewer tubules in Matrigel than ASCs from abdominoplasty patients, suggesting decreased vasculogenic activity. Jeffrey Lisiecki, Jacob Rinkinen, Oluwatobi Eboda, Jonathan Peterson, Sara De La Rosa, Shailesh Agarwal, Justin Dimick, Oliver A. Varban, Paul S. Cederna, Stewart C. Wang, and Benjamin Levi Copyright © 2014 Jeffrey Lisiecki et al. All rights reserved. A Standardized Critical Size Defect Model in Normal and Osteoporotic Rats to Evaluate Bone Tissue Engineered Constructs Tue, 11 Mar 2014 09:15:33 +0000 Tissue engineered constructs should be tested for their efficacy not only in normal but also in osteoporotic bone. The rat is an established animal model for osteoporosis and is used often for bone healing studies. In this study a defined and standardized critical size defect model in the rat suitable for screening new tissue engineered constructs in normal and osteoporotic bone is described and validated. Normal and ovariectomised Wistar rats received a unilateral middiaphyseal 5 mm defect in the femur, which was instrumented with a radiolucent PEEK plate fixed with angular stable titanium screws and left untreated. All animals were euthanized eight weeks after defect surgery and the bone healing was evaluated using radiographs, computed tomography measurements, and histology. The developed fixation system provided good stability, even in osteoporotic bone. The implants and ancillary instruments ensured consistent and facile placement of the PEEK plates. The untreated defects did not heal without intervention making the model a well-defined and standardized critical size defect model highly useful for evaluating tissue engineered solutions in normal and osteoporotic bone. Livia Poser, Romano Matthys, Peter Schawalder, Simon Pearce, Mauro Alini, and Stephan Zeiter Copyright © 2014 Livia Poser et al. All rights reserved. Nanosized Mesoporous Bioactive Glass/Poly(lactic-co-glycolic Acid) Composite-Coated CaSiO3 Scaffolds with Multifunctional Properties for Bone Tissue Engineering Sun, 02 Mar 2014 12:09:56 +0000 It is of great importance to prepare multifunctional scaffolds combining good mechanical strength, bioactivity, and drug delivery ability for bone tissue engineering. In this study, nanosized mesoporous bioglass/poly(lactic-co-glycolic acid) composite-coated calcium silicate scaffolds, named NMBG-PLGA/CS, were successfully prepared. The morphology and structure of the prepared scaffolds were characterized by scanning electron microscopy and X-ray diffraction. The effects of NMBG on the apatite mineralization activity and mechanical strength of the scaffolds and the attachment, proliferation, and alkaline phosphatase activity of MC3T3 cells as well as drug ibuprofen delivery properties were systematically studied. Compared to pure CS scaffolds and PLGA/CS scaffolds, the prepared NMBG-PLGA/CS scaffolds had greatly improved apatite mineralization activity in simulated body fluids, much higher mechanical property, and supported the attachment of MC3T3 cells and enhanced the cell proliferation and ALP activity. Furthermore, the prepared NMBG-PLGA/CS scaffolds could be used for delivering ibuprofen with a sustained release profile. Our study suggests that the prepared NMBG-PLGA/CS scaffolds have improved physicochemical, biological, and drug-delivery property as compared to conventional CS scaffolds, indicating that the multifunctional property of the prepared scaffolds for the potential application of bone tissue engineering. Mengchao Shi, Dong Zhai, Lang Zhao, Chengtie Wu, and Jiang Chang Copyright © 2014 Mengchao Shi et al. All rights reserved. RANKL Expression in Periodontal Disease: Where Does RANKL Come from? Thu, 27 Feb 2014 07:02:34 +0000 Periodontitis is an inflammatory disease characterized by periodontal pocket formation and alveolar bone resorption. Periodontal bone resorption is induced by osteoclasts and receptor activator of nuclear factor-κB ligand (RANKL) which is an essential and central regulator of osteoclast development and osteoclast function. Therefore, RANKL plays a critical role in periodontal bone resorption. In this review, we have summarized the sources of RANKL in periodontal disease and explored which factors may regulate RANKL expression in this disease. Bin Chen, Wenlei Wu, Weibin Sun, Qian Zhang, Fuhua Yan, and Yin Xiao Copyright © 2014 Bin Chen et al. All rights reserved. Calcium Phosphate Based Three-Dimensional Cold Plotted Bone Scaffolds for Critical Size Bone Defects Wed, 26 Feb 2014 13:36:35 +0000 Bone substitutes, like calcium phosphate, are implemented more frequently in orthopaedic surgery to reconstruct critical size defects, since autograft often results in donor site morbidity and allograft can transmit diseases. A novel bone cement, based on β-tricalcium phosphate, polyethylene glycol, and trisodium citrate, was developed to allow the rapid manufacturing of scaffolds, by extrusion freeform fabrication, at room temperature. The cement composition exhibits good resorption properties and serves as a basis for customised (e.g., drug or growth factor loaded) scaffolds for critical size bone defects. In vitro toxicity tests confirmed proliferation and differentiation of ATDC5 cells in scaffold-conditioned culture medium. Implantation of scaffolds in the iliac wing of sheep showed bone remodelling throughout the defects, outperforming the empty defects on both mineral volume and density present in the defect after 12 weeks. Both scaffolds outperformed the autograft filled defects on mineral density, while the mineral volume present in the scaffold treated defects was at least equal to the mineral volume present in the autograft treated defects. We conclude that the formulated bone cement composition is suitable for scaffold production at room temperature and that the established scaffold material can serve as a basis for future bone substitutes to enhance de novo bone formation in critical size defects. Christian J. D. Bergmann, Jim C. E. Odekerken, Tim J. M. Welting, Franz Jungwirth, Declan Devine, Ludovic Bouré, Stephan Zeiter, Lodewijk W. van Rhijn, Rainer Telle, Horst Fischer, and Pieter J. Emans Copyright © 2014 Christian J. D. Bergmann et al. All rights reserved. Comparing Microspheres with Different Internal Phase of Polyelectrolyte as Local Drug Delivery System for Bone Tuberculosis Therapy Sun, 23 Feb 2014 00:00:00 +0000 We use hydrophobic poly(lactic-co-glycolic) acid (PLGA) to encapsulate hydrophilic ofloxacin to form drug loading microspheres. Hyaluronic acid (HA) and polylysine (Pls) were used as internal phase additives to see their influences on the drug loading and releasing. Double emulsion (water-in-oil-in-water) solvent extraction/evaporation method was used for the purpose. Particle size analysis display that the polyelectrolytes have low impact on the microsphere average size and distribution. Scanning electron microscope (SEM) pictures show the wrinkled surface resulted by the internal microcavity of the microspheres. Microspheres with HA inside have higher drug loading amounts than microspheres with Pls inside. The loading drug amounts of the microspheres increase with the HA amounts inside, while decreasing with the Pls amounts inside. All the polyelectrolytes adding groups have burst release observed in experiments. The microspheres with Pls internal phase have faster release rate than the HA groups. Among the same polyelectrolyte internal phase groups, the release rate increases with the amounts increasing when Pls is inside, while it decreases with the amounts increasing when HA is inside. Gang Wu, Long Chen, Hong Li, Chun-Ling Deng, and Xiao-Feng Chen Copyright © 2014 Gang Wu et al. All rights reserved. The Effect of Hypoxia on the Stemness and Differentiation Capacity of PDLC and DPC Thu, 20 Feb 2014 09:35:14 +0000 Introduction. Stem cells are regularly cultured under normoxic conditions. However, the physiological oxygen tension in the stem cell niche is known to be as low as 1-2% oxygen, suggesting that hypoxia has a distinct impact on stem cell maintenance. Periodontal ligament cells (PDLCs) and dental pulp cells (DPCs) are attractive candidates in dental tissue regeneration. It is of great interest to know whether hypoxia plays a role in maintaining the stemness and differentiation capacity of PDLCs and DPCs. Methods. PDLCs and DPCs were cultured either in normoxia (20% O2) or hypoxia (2% O2). Cell viability assays were performed and the expressions of pluripotency markers (Oct-4, Sox2, and c-Myc) were detected by qRT-PCR and western blotting. Mineralization, glycosaminoglycan (GAG) deposition, and lipid droplets formation were assessed by Alizarin red S, Safranin O, and Oil red O staining, respectively. Results. Hypoxia did not show negative effects on the proliferation of PDLCs and DPCs. The pluripotency markers and differentiation potentials of PDLCs and DPCs significantly increased in response to hypoxic environment. Conclusions. Our findings suggest that hypoxia plays an important role in maintaining the stemness and differentiation capacity of PDLCs and DPCs. Yinghong Zhou, Wei Fan, and Yin Xiao Copyright © 2014 Yinghong Zhou et al. All rights reserved.