BioMed Research International: Tissue Engineering The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . 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. Characterization of an Ovine Bilateral Critical Sized Bone Defect Iliac Wing Model to Examine Treatment Modalities Based on Bone Tissue Engineering Sun, 16 Feb 2014 12:35:23 +0000 Critical sized bone defect (CSBD) animal models are used to evaluate and confirm efficacy and potency of new treatment modalities based on bone tissue engineering before the latter can be applied in clinical practice. In this study, a bilateral CSBD model in the iliac wings of sheep is described in detail. To demonstrate that this is a large animal CSBD model in sheep, bone healing within the defect left empty (negative control) or filled with autologous corticocancellous bone graft (clinical gold standard, positive control) was assessed using micro-CT, histology, histomorphometric, and fluorochrome analysis. After three months, new bone into the defect site was formed across the whole defect in the positive controls but limited to the edge of the defects in the negative controls. Bone volume in the positive controls was statistically higher than in the negative controls, with the latter having less than 10% new bone growth. There were no intraoperative or postoperative complications. The model described here represents a reliable and reproducible bilateral CSBD in sheep with low morbidity that can be used for in vivo evaluation of new treatment modalities based on bone tissue engineering. Jennifer L. Lansdowne, Declan Devine, Ursula Eberli, Pieter Emans, Tim J. M. Welting, Jim C. E. Odekerken, Damiano Schiuma, Martin Thalhauser, Ludovic Bouré, and Stephan Zeiter Copyright © 2014 Jennifer L. Lansdowne et al. All rights reserved. Interleukin-10 Inhibits Bone Resorption: A Potential Therapeutic Strategy in Periodontitis and Other Bone Loss Diseases Sun, 16 Feb 2014 12:05:40 +0000 Periodontitis and other bone loss diseases, decreasing bone volume and strength, have a significant impact on millions of people with the risk of tooth loss and bone fracture. The integrity and strength of bone are maintained through the balance between bone resorption and bone formation by osteoclasts and osteoblasts, respectively, so the loss of bone results from the disruption of such balance due to increased resorption or/and decreased formation of bone. The goal of therapies for diseases of bone loss is to reduce bone loss, improve bone formation, and then keep healthy bone density. Current therapies have mostly relied on long-term medication, exercise, anti-inflammatory therapies, and changing of the life style. However there are some limitations for some patients in the effective treatments for bone loss diseases because of the complexity of bone loss. Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine, and recent studies have indicated that IL-10 can contribute to the maintenance of bone mass through inhibition of osteoclastic bone resorption and regulation of osteoblastic bone formation. This paper will provide a brief overview of the role of IL-10 in bone loss diseases and discuss the possibility of IL-10 adoption in therapy of bone loss diseases therapy. Qian Zhang, Bin Chen, Fuhua Yan, Jianbin Guo, Xiaofeng Zhu, Shouzhi Ma, and Wenrong Yang Copyright © 2014 Qian Zhang et al. All rights reserved. Association between Postmenopausal Osteoporosis and Experimental Periodontitis Mon, 10 Feb 2014 13:02:10 +0000 To investigate the correlation between postmenopausal osteoporosis (PMO) and the pathogenesis of periodontitis, ovariectomized rats were generated and the experimental periodontitis was induced using a silk ligature. The inflammatory factors and bone metabolic markers were measured in the serum and periodontal tissues of ovariectomized rats using an automatic chemistry analyzer, enzyme-linked immunosorbent assays, and immunohistochemistry. The bone mineral density of whole body, pelvis, and spine was analyzed using dual-energy X-ray absorptiometry and image analysis. All data were analyzed using SPSS 13.0 statistical software. It was found that ovariectomy could upregulate the expression of interleukin- (IL-)6, the receptor activator of nuclear factor-κB ligand (RANKL), and osteoprotegerin (OPG) and downregulate IL-10 expression in periodontal tissues, which resulted in progressive alveolar bone loss in experimental periodontitis. This study indicates that changes of cytokines and bone turnover markers in the periodontal tissues of ovariectomized rats contribute to the damage of periodontal tissues. Kai Luo, Souzhi Ma, Jianbin Guo, Yongling Huang, Fuhua Yan, and Yin Xiao Copyright © 2014 Kai Luo et al. All rights reserved. Regenerative Repair of Damaged Meniscus with Autologous Adipose Tissue-Derived Stem Cells Thu, 30 Jan 2014 06:35:35 +0000 Mesenchymal stem cells (MSCs) are defined as pluripotent cells found in numerous human tissues, including bone marrow and adipose tissue. Such MSCs, isolated from bone marrow and adipose tissue, have been shown to differentiate into bone and cartilage, along with other types of tissues. Therefore, MSCs represent a promising new therapy in regenerative medicine. The initial treatment of meniscus tear of the knee is managed conservatively with nonsteroidal anti-inflammatory drugs and physical therapy. When such conservative treatment fails, an arthroscopic resection of the meniscus is necessary. However, the major drawback of the meniscectomy is an early onset of osteoarthritis. Therefore, an effective and noninvasive treatment for patients with continuous knee pain due to damaged meniscus has been sought. Here, we present a review, highlighting the possible regenerative mechanisms of damaged meniscus with MSCs (especially adipose tissue-derived stem cells (ASCs)), along with a case of successful repair of torn meniscus with significant reduction of knee pain by percutaneous injection of autologous ASCs into an adult human knee. Jaewoo Pak, Jung Hun Lee, and Sang Hee Lee Copyright © 2014 Jaewoo Pak et al. All rights reserved. rhPDGF-BB Promotes Proliferation and Osteogenic Differentiation of Bone Marrow Stromal Cells from Streptozotocin-Induced Diabetic Rats through ERK Pathway Wed, 29 Jan 2014 00:00:00 +0000 Management of nonunion fracture and massive segmental bone defects in diabetes remains a challenging clinical problem. Bone marrow stromal cells (BMSCs) are crucial for bone remodeling and hold promise for bone regeneration. However, we have showed previously that diabetes can affect the proliferation and osteogenic potential of BMSCs adversely and a strategy to attenuate the impaired functions of BMSCs is required. Platelet-derived growth factor-BB (PDGF-BB) plays an important role in bone formation. However, little information is available about its effect on diabetic BMSCs. In this study, BMSCs were isolated from streptozotocin-induced diabetic rats. After treatment with recombinant human PDGF-BB (rhPDGF-BB), diabetic BMSCs demonstrated enhanced cell proliferation and osteogenic differentiation based on increased expressions of osteogenic genes (Runx2, alkaline phosphatase, and osteocalcin) and Runx2 protein, as well as upregulated alkaline phosphatase activity and mineralization. Furthermore, blocking extracellular signal regulated kinase (ERK) pathway by inhibitor PD98059 repressed the enhanced proliferation and osteogenic differentiation in diabetic BMSCs induced by rhPDGF-BB. Together, these results indicated that rhPDGF-BB stimulates proliferation and osteogenic differentiation partially through ERK pathway in diabetic BMSCs. Therefore, modulation of diabetic BMSCs could augment BMSCs function affected by diabetes and holds significance for future strategies to treat diabetic bone complications. Yanfang Zhao, Songmei Zhang, Deliang Zeng, Lunguo Xia, Ashwini Lamichhane, Xinquan Jiang, and Fuqiang Zhang Copyright © 2014 Yanfang Zhao et al. All rights reserved. Development of a Stereotaxic Device for Low Impact Implantation of Neural Constructs or Pieces of Neural Tissues into the Mammalian Brain Thu, 23 Jan 2014 07:02:33 +0000 Implanting pieces of tissue or scaffolding material into the mammalian central nervous system (CNS) is wrought with difficulties surrounding the size of tools needed to conduct such implants and the ability to maintain the orientation and integrity of the constructs during and after their transplantation. Here, novel technology has been developed that allows for the implantation of neural constructs or intact pieces of neural tissue into the CNS with low trauma. By “laying out” (instead of forcibly expelling) the implantable material from a thin walled glass capillary, this technology has the potential to enhance neural transplantation procedures by reducing trauma to the host brain during implantation and allowing for the implantation of engineered/dissected tissues or constructs in such a way that their orientation and integrity are maintained in the host. Such technology may be useful for treating various CNS disorders which require the reestablishment of point-to-point contacts (e.g., Parkinson’s disease) across the adult CNS, an environment which is not normally permissive to axonal growth. Andrzej Jozwiak, Yiwen Liu, Ying Yang, and Monte A. Gates Copyright © 2014 Andrzej Jozwiak et al. All rights reserved. PHBV/PAM Scaffolds with Local Oriented Structure through UV Polymerization for Tissue Engineering Wed, 22 Jan 2014 11:08:38 +0000 Locally oriented tissue engineering scaffolds can provoke cellular orientation and direct cell spread and migration, offering an exciting potential way for the regeneration of the complex tissue. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffolds with locally oriented hydrophilic polyacrylamide (PAM) inside the macropores of the scaffolds were achieved through UV graft polymerization. The interpenetrating PAM chains enabled good interconnectivity of PHBV/PAM scaffolds that presented a lower porosity and minor diameter of pores than PHBV scaffolds. The pores with diameter below 100 μm increased to 82.15% of PHBV/PAM scaffolds compared with 31.5% of PHBV scaffolds. PHBV/PAM scaffold showed a much higher compressive elastic modulus than PHBV scaffold due to PAM stuffing. At 5 days of culturing, sheep chondrocytes spread along the similar direction in the macropores of PHBV/PAM scaffolds. The locally oriented PAM chains might guide the attachment and spreading of chondrocytes and direct the formation of microfilaments via contact guidance. Yu Ke, Gang Wu, and Yingjun Wang Copyright © 2014 Yu Ke et al. All rights reserved. Chemical Synthesis, Characterisation, and Biocompatibility of Nanometre Scale Porous Anodic Aluminium Oxide Membranes for Use as a Cell Culture Substrate for the Vero Cell Line: A Preliminary Study Tue, 21 Jan 2014 08:04:31 +0000 In this preliminary study we investigate for the first time the biomedical potential of using porous anodic aluminium oxide (AAO) membranes as a cell substrate for culturing the Cercopithecus aethiops (African green monkey) Kidney (Vero) epithelial cell line. One advantage of using the inorganic AAO membrane is the presence of nanometre scale pore channels that allow the exchange of molecules and nutrients across the membrane. The size of the pore channels can be preselected by adjusting the controlling parameters of a temperature controlled two-step anodization process. The cellular interaction and response of the Vero cell line with an in-house synthesised AAO membrane, a commercially available membrane, and a glass control were assessed by investigating cell adhesion, morphology, and proliferation over a 72 h period. The number of viable cells proliferating over the respective membrane surfaces revealed that the locally produced in-house AAO membrane had cells numbers similar to the glass control. The study revealed evidence of focal adhesion sites over the surface of the nanoporous membranes and the penetration of cellular extensions into the pore structure as well. The outcome of the study has revealed that nanometre scale porous AAO membranes have the potential to become practical cell culture scaffold substrates with the capability to enhance adhesion and proliferation of Vero cells. Gérrard Eddy Jai Poinern, Xuan Thi Le, Mark O'Dea, Thomas Becker, and Derek Fawcett Copyright © 2014 Gérrard Eddy Jai Poinern et al. All rights reserved. A Novel Platelet Concentrate: Titanium-Prepared Platelet-Rich Fibrin Tue, 21 Jan 2014 00:00:00 +0000 We developed a new product called titanium-prepared platelet-rich fibrin (T-PRF). The T-PRF method is based on the hypothesis that titanium may be more effective in activating platelets than the silica activators used with glass tubes in Chouckroun’s leukocyte- and platelet-rich fibrin (L-PRF) method. In this study, we aimed to define the structural characteristics of T-PRF and compare it with L-PRF. Blood samples were collected from 10 healthy male volunteers. The blood samples were drawn using a syringe. Nine milliliters was transferred to a dry glass tube, and 9 mL was transferred to a titanium tube. Half of each clot (i.e., the blood that was clotted using T-PRF or L-PRF) was processed with a scanning electron microscope (SEM). The other half of each clot was processed for fluorescence microscopy analysis and light microscopy analysis. The T-PRF samples seemed to have a highly organized network with continuous integrity compared to the other L-PRF samples. Histomorphometric analysis showed that T-PRF fibrin network covers larger area than L-PRF fibrin network; also fibrin seemed thicker in the T-PRF samples. This is the first human study to define T-PRF as an autogenous leukocyte- and platelet-rich fibrin product. The platelet activation by titanium seems to offer some high characteristics to T-PRF. Mustafa Tunalı, Hakan Özdemir, Zafer Küçükodacı, Serhan Akman, Emre Yaprak, Hülya Toker, and Erhan Fıratlı Copyright © 2014 Mustafa Tunalı et al. All rights reserved. Synergistic Effects of Orbital Shear Stress on In Vitro Growth and Osteogenic Differentiation of Human Alveolar Bone-Derived Mesenchymal Stem Cells Tue, 14 Jan 2014 11:17:00 +0000 Cellular behavior is dependent on a variety of physical cues required for normal tissue function. In order to mimic native tissue environments, human alveolar bone-derived mesenchymal stem cells (hABMSCs) were exposed to orbital shear stress (OSS) in a low-speed orbital shaker. The synergistic effects of OSS on proliferation and differentiation of hABMSCs were investigated. In particular, we induced the osteoblastic differentiation of hABMSCs cultured in the absence of OM by exposing hABMSCs to OSS (0.86–1.51 dyne/cm2). Activation of Cx43 was associated with exposure of hABMSCs to OSS. The viability of cells stimulated for 10, 30, 60, 120, and 180 min/day increased by approximately 10% compared with that of control. The OSS groups with stimulation of 10, 30, and 60 min/day had more intense mineralized nodules compared with the control group. In quantification of vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) protein, VEGF protein levels under stimulation for 10, 60, and 180 min/day and BMP-2 levels under stimulation for 60, 120, and 180 min/day were significantly different compared with those of the control. In conclusion, the results indicated that exposing hABMSCs to OSS enhanced their differentiation and maturation. Ki Taek Lim, Jin Hexiu, Jangho Kim, Hoon Seonwoo, Pill-Hoon Choung, and Jong Hoon Chung Copyright © 2014 Ki Taek Lim et al. All rights reserved. Erratum to “Detergent-Enzymatic Decellularization of Swine Blood Vessels: Insight on Mechanical Properties for Vascular Tissue Engineering” Sun, 05 Jan 2014 14:14:16 +0000 Alessandro F. Pellegata, M. Adelaide Asnaghi, Ilaria Stefani, Anna Maestroni, Silvia Maestroni, Tommaso Dominioni, Sandro Zonta, Gianpaolo Zerbini, and Sara Mantero Copyright © 2014 Alessandro F. Pellegata et al. All rights reserved. αVβ5 and CD44 Are Oxygen-Regulated Human Embryonic Stem Cell Attachment Factors Thu, 26 Dec 2013 12:38:40 +0000 Human embryonic stem cells (hESCs) have great potential for clinical therapeutic use. However, relatively little is known of the mechanisms which dictate their specificity of adhesion to substrates through adhesion proteins including integrins. Previous observations demonstrated enhanced clonogenicity in reduced oxygen culture systems. Here, we demonstrated via antibody blocking experiments that αVβ5 and α6 significantly promoted hESC attachment in 2% O2 only, whereas blockage of CD44 inhibited cell attachment in 21% O2 alone. Immunofluorescence confirmed expression of αVβ5 and CD44 in both 2% O2 and 21% O2 cultured hESCs while flow cytometry revealed significantly higher αVβ5 expression in 2% O2 versus 21% O2 cultured hESCs and higher CD44 expression in 21% O2 versus 2% O2 cultured hESCs. Adhered hESCs following blockage of αVβ5 in 2% O2 displayed a reduction in nuclear colocalisation of Oct-4 and Nanog with little effect observed in 21% O2. Blockage of CD44 had the converse effect with dramatic reductions in nuclear colocalisation of Oct-4 and Nanog in 21% O2 cultured hESC which retained adherence, but not in 2% O2 cultured cells. Identification of oxygen-dependent substrate attachment mechanisms in hESCs has the potential to play a role in the development of novel substrates to improve hESC attachment and culture. Deepak Kumar, Saniya Gupta, Ying Yang, and Nicholas R. Forsyth Copyright © 2013 Deepak Kumar et al. All rights reserved. Cellular Performance Comparison of Biomimetic Calcium Phosphate Coating and Alkaline-Treated Titanium Surface Tue, 24 Dec 2013 08:55:32 +0000 The influence of biomimetic calcium phosphate coating on osteoblasts behavior in vitro is not well established yet. In this study, we investigated the behavior of osteoblastic rat osteosarcoma 17/2.8 cells (ROS17/2.8) on two groups of biomaterial surfaces: alkaline-treated titanium surface (ATT) and biomimetic calcium phosphate coated ATT (CaP). The cell attachment, proliferation, differentiation, and morphology on these surfaces were extensively evaluated to reveal the impact of substrate surface on osteoblastic cell responses. It was found that the ROS17/2.8 cells cultured on the ATT surface had higher attachment and proliferation rates compared to those on the CaP surface. Our results also showed that the calcium phosphate coatings generated in this work have an inhibiting effect on osteoblast adhesion and further influenced the proliferation and differentiation of osteoblast compared to the ATT surface in vitro. Cells on the ATT surface also exhibited a higher alkaline phosphatase activity than on the CaP surface after two weeks of culture. Immunofluorescence staining and scanning electron microscopy results showed that the cells adhered and spread faster on the ATT surface than on the CaP surface. These results collectively suggested that substrate surface properties directly influence cell adhesion on different biomaterials, which would result in further influence on the cell proliferation and differentiation. Xiaohua Yu and Mei Wei Copyright © 2013 Xiaohua Yu and Mei Wei. All rights reserved. Enhancing the Migration Ability of Mesenchymal Stromal Cells by Targeting the SDF-1/CXCR4 Axis Thu, 05 Dec 2013 17:44:51 +0000 Mesenchymal stromal cells (MSCs) are currently being investigated in numerous clinical trials of tissue repair and various immunological disorders based on their ability to secrete trophic factors and to modulate inflammatory responses. MSCs have been shown to migrate to sites of injury and inflammation in response to soluble mediators including the chemokine stromal cell-derived factor-(SDF-)1, but during in vitro culture expansion MSCs lose surface expression of key homing receptors particularly of the SDF-1 receptor, CXCR4. Here we review studies on enhancement of SDF-1-directed migration of MSCs with the premise that their improved recruitment could translate to therapeutic benefits. We describe our studies on approaches to increase the CXCR4 expression in in vitro-expanded cord blood-derived MSCs, namely, transfection, using the commercial liposomal reagent IBAfect, chemical treatment with the histone deacetylase inhibitor valproic acid, and exposure to recombinant complement component C1q. These methodologies will be presented in the context of other cell targeting and delivery strategies that exploit pathways involved in MSC migration. Taken together, these findings indicate that MSCs can be manipulated in vitro to enhance their in vivo recruitment and efficacy for tissue repair. Leah A. Marquez-Curtis and Anna Janowska-Wieczorek Copyright © 2013 Leah A. Marquez-Curtis and Anna Janowska-Wieczorek. All rights reserved. The Study on Biocompatibility of Porous nHA/PLGA Composite Scaffolds for Tissue Engineering with Rabbit Chondrocytes In Vitro Wed, 27 Nov 2013 10:37:29 +0000 Objective. To examine the biocompatibility of a novel nanohydroxyapatite/poly[lactic-co-glycolic acid] (nHA/PLGA) composite and evaluate its feasibility as a scaffold for cartilage tissue engineering. Methods. Chondrocytes of fetal rabbit were cultured with nHA/PLGA scaffold in vitro and the cell viability was assessed by MTT assay first. Cells adhering to nHA/PLGA scaffold were then observed by inverted microscope and scanning electron microscope (SEM). The cell cycle profile was analyzed by flow cytometry. Results. The viability of the chondrocytes on the scaffold was not affected by nHA/PLGA comparing with the control group as it was shown by MTT assay. Cells on the surface and in the pores of the scaffold increased in a time-dependent manner. Results obtained from flow cytometry showed that there was no significant difference in cell cycle profiles between the coculture group and control (). Conclusion. The porous nHA/PLGA composite scaffold is a biocompatible and good kind of scaffold for cartilage tissue engineering. Lei Chen, Wei-Min Zhu, Zhi-Qiang Fei, Jie-Lin Chen, Jian-Yi Xiong, Ju-Feng Zhang, Li Duan, Jianghong Huang, Zhiyong Liu, Daping Wang, and Yanjun Zeng Copyright © 2013 Lei Chen et al. All rights reserved. Chitosan Dermal Substitute and Chitosan Skin Substitute Contribute to Accelerated Full-Thickness Wound Healing in Irradiated Rats Wed, 13 Nov 2013 10:38:40 +0000 Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%), longest epithelial tongue (1.62 ± 0.13 mm), and shortest migratory tongue distance (7.11 ± 0.25 mm). The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02 cm) and chitosan skin substitute (0.16 ± 0.05 cm) were significantly decreased () compared with duoderm (0.45 ± 0.11 cm). Human leukocyte antigen (HLA) expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation. Abu Bakar Mohd Hilmi, Ahmad Sukari Halim, Hasnan Jaafar, Abu Bakar Asiah, and Asma Hassan Copyright © 2013 Abu Bakar Mohd Hilmi et al. All rights reserved. Biocompatibility Assessment of Novel Collagen-Sericin Scaffolds Improved with Hyaluronic Acid and Chondroitin Sulfate for Cartilage Regeneration Thu, 07 Nov 2013 15:38:10 +0000 Cartilage tissue engineering (CTE) applications are focused towards the use of implantable biohybrids consisting of biodegradable scaffolds combined with in vitro cultured cells. Hyaluronic acid (HA) and chondroitin sulfate (CS) were identified as the most potent prochondrogenic factors used to design new biomaterials for CTE, while human adipose-derived stem cells (ASCs) were proved to display high chondrogenic potential. In this context, our aim was not only to build novel 3D porous scaffolds based on natural compounds but also to evaluate their in vitro biological performances. Therefore, for prospective CTE, collagen-sericin (Coll-SS) scaffolds improved with HA (5% or 10%) and CS (5% or 10%) were used as temporary physical supports for ASCs and were analyzed in terms of structural, thermal, morphological, and swelling properties and cytotoxic potential. To complete biocompatibility data, ASCs viability and proliferation potential were also assessed. Our studies revealed that Coll-SS hydrogels improved with 10% HA and 5% CS displayed the best biological performances in terms of cell viability, proliferation, morphology, and distribution. Thus, further work will address a novel 3D system including both HA 10% and CS 5% glycoproteins, which will probably be exposed to prochondrogenic conditions in order to assess its potential use in CTE applications. Sorina Dinescu, Bianca Gălăţeanu, Mădălina Albu, Adriana Lungu, Eugen Radu, Anca Hermenean, and Marieta Costache Copyright © 2013 Sorina Dinescu et al. All rights reserved. The Use of Carbon Nanotubes to Reinforce 45S5 Bioglass-Based Scaffolds for Tissue Engineering Applications Mon, 04 Nov 2013 15:02:11 +0000 Bioglass has been used for bone-filling material in bone tissue engineering, but its lean mechanical strength limits its applications in load-bearing positions. Carbon nanotubes (CNTs), with their high aspect ratio and excellent mechanical properties, have the potential to strengthen and toughen bioactive glass material without offsetting its bioactivity. Therefore, in this research, multiwall carbon nanotube (MWCNT)/45S5 Bioglass composite scaffolds have been successfully prepared by means of freeze casting process. 45S5 Bioglass was synthesized by the sol-gel processing method. The obtained material was characterized with X-ray powder diffraction (XRD). The mechanical properties of the scaffolds, such as compression strength and elastic modulus, were measured. Finally, compared with the scaffolds prepared by 100% 45S5 Bioglass powders, the addition of 0.25 wt.% MWCNTs increases the compressive strength and elastic modulus of 45S5 Bioglass scaffolds from 2.08 to 4.56 MPa (a 119% increase) and 111.50 to 266.59 MPa (a 139% increase), respectively. R. Touri, F. Moztarzadeh, Z. Sadeghian, D. Bizari, M. Tahriri, and M. Mozafari Copyright © 2013 R. Touri et al. All rights reserved. Transplantation of Autologous Minced Bladder Mucosa for a One-Step Reconstruction of a Tissue Engineered Bladder Conduit Thu, 31 Oct 2013 18:39:27 +0000 Surgical intervention is sometimes needed to create a conduit from the abdominal wall to the bladder for self-catheterization. We developed a method for tissue engineering a conduit for bladder emptying without in vitro cell culturing as a one-step procedure. In a porcine animal model bladder, wall tissue was excised and the mucosa was minced to small particles. The particles were attached to a tube in a 1 : 3 expansion rate with fibrin glue and transplanted back by attaching the tube to the bladder and through the abdominal wall. Sham served as controls. After 4-5 weeks, conduits were assessed in respect to macroscopic and microscopic appearance in 6 pigs. Two pigs underwent radiology before termination. Gross examination revealed a patent conduit with an opening to the bladder. Histology and immunostaining showed a multilayered transitional uroepithelium in all cases. Up to 89% of the luminal surface area was neoepithelialized but with a loose attachment to the submucosa. No epithelium was found in control animals. CT imaging revealed a patent channel that could be used for filling and emptying the bladder. Animals that experienced surgical complications did not form conduits. Minced autologous bladder mucosa can be transplanted around a tubular mold to create a conduit to the urinary bladder without in vitro culturing. Gisela Reinfeldt Engberg, Johan Lundberg, Clara Ibel Chamorro, Agneta Nordenskjöld, and Magdalena Fossum Copyright © 2013 Gisela Reinfeldt Engberg et al. All rights reserved. In Vitro Effects of Low-Intensity Pulsed Ultrasound Stimulation on the Osteogenic Differentiation of Human Alveolar Bone-Derived Mesenchymal Stem Cells for Tooth Tissue Engineering Mon, 30 Sep 2013 08:54:54 +0000 Ultrasound stimulation produces significant multifunctional effects that are directly relevant to alveolar bone formation, which is necessary for periodontal healing and regeneration. We focused to find out effects of specific duty cycles and the percentage of time that ultrasound is being generated over one on/off pulse period, under ultrasound stimulation. Low-intensity pulsed ultrasound ((LIPUS) 1 MHz) with duty cycles of 20% and 50% was used in this study, and human alveolar bone-derived mesenchymal stem cells (hABMSCs) were treated with an intensity of 50 mW/cm2 and exposure time of 10 min/day. hABMSCs exposed at duty cycles of 20% and 50% had similar cell viability (O.D.), which was higher () than that of control cells. The alkaline phosphatase (ALP) was significantly enhanced at 1 week with LIPUS treatment in osteogenic cultures as compared to control. Gene expressions showed significantly higher expression levels of CD29, CD44, COL1, and OCN in the hABMSCs under LIPUS treatment when compared to control after two weeks of treatment. The effects were partially controlled by LIPUS treatment, indicating that modulation of osteogenesis in hABMSCs was related to the specific stimulation. Furthermore, mineralized nodule formation was markedly increased after LIPUS treatment than that seen in untreated cells. Through simple staining methods such as Alizarin red and von Kossa staining, calcium deposits generated their highest levels at about 3 weeks. These results suggest that LIPUS could enhance the cell viability and osteogenic differentiation of hABMSCs, and could be part of effective treatment methods for clinical applications. KiTaek Lim, Jangho Kim, Hoon Seonwoo, Soo Hyun Park, Pill-Hoon Choung, and Jong Hoon Chung Copyright © 2013 KiTaek Lim et al. All rights reserved. P.R.L. Platelet Rich Lipotransfert: Our Experience and Current State of Art in the Combined Use of Fat and PRP Sat, 28 Sep 2013 11:49:46 +0000 The authors report their experience about the use of P.R.L. PLATELET RICH LIPOTRANSFERT method (platelet rich plasma mixed fat grafting) in 223 patients affected by soft tissue defects (ulcers, Romberg syndrome, Hemifacial atrophy, loss of substance, and signs of aging). This paper introduces the reader to PRP therapy and reviews the current literature on this emerging treatment modality, showing at the current clinical use of PRP in plastic and reconstructive surgery, with description of innovative methods and future prospects. This technique provides a promising alternative to surgery by promoting safe and natural healing. Here recent studies concerning the use of PRP in the treatment of chronic ulcers and soft tissue defect are reviewed. V. Cervelli, I. Bocchini, C. Di Pasquali, B. De Angelis, G. Cervelli, C. B. Curcio, A. Orlandi, M. G. Scioli, E. Tati, P. Delogu, and Pietro Gentile Copyright © 2013 V. Cervelli et al. All rights reserved. Osteogenic Matrix Cell Sheet Transplantation Enhances Early Tendon Graft to Bone Tunnel Healing in Rabbits Wed, 11 Sep 2013 13:59:53 +0000 The objective of this study was to determine whether osteogenic matrix cell sheets (OMCS) could induce bone formation around grafted tendons, thereby enhancing early stage tendon to bone tunnel healing in skeletally mature male Japanese white rabbits. First, the osteogenic potential of rabbit OMCS was evaluated. Then, the OMCS were transplanted into the interface between the grafted tendon and the bone tunnel created at the tibia. Histological assessments and biomechanical tensile testing were performed after 3 weeks. The rabbit OMCS showed high alkaline phosphatase (ALP) activity, positive staining of ALP, and osteogenic potential when transplanted subcutaneously with beta tricalcium phosphate disks. Newly formed bony walls and positive collagen type I staining were seen around the grafted tendon with OMCS transplantation, whereas such bony walls were thinner or less frequent without OMCS transplantation. Micro-computed tomography images showed significantly higher bone volume in the OMCS transplantation group. The pullout strength was significantly higher with OMCS ( N/mm2) than without OMCS ( N/mm2). These results show that OMCS enhance early tendon to bone tunnel healing. This method can be applied to cases requiring early tendon to bone tunnel healing after ligament reconstruction surgery. Yusuke Inagaki, Kota Uematsu, Manabu Akahane, Yusuke Morita, Munehiro Ogawa, Tomoyuki Ueha, Takamasa Shimizu, Tomohiko Kura, Kenji Kawate, and Yasuhito Tanaka Copyright © 2013 Yusuke Inagaki et al. All rights reserved. Myogenic Differentiation of Mesenchymal Stem Cells in a Newly Developed Neurotised AV-Loop Model Tue, 10 Sep 2013 14:31:43 +0000 Generation of axially vascularized muscle tissue constitutes a promising new approach to restoration of damaged muscle tissue. Mesenchymal stemcells (MSC), with their ability to be expanded to large cell numbers without losing their differentiation capacity into the myogenic lineage, could offer a promising cell source to generate neomuscle tissue. In vitro experiments showed that cocultures of primary myoblasts and MSC undergo myogenic differentiation by stimulation with bFGF and dexamethasone. A newly developed AV-Loop model with neurotization was established in this study. It encompasses axial vascularization and the additional implantation of a motor nerve serving as myogenic stimulator. Myoblasts and MSCs were coimplantated in a prevascularized isolation chamber. Cells were differentiated by addition of bFGF and dexamethasone plus implantation of a motor nerve. After 8 weeks, we could observe areas of myogenic differentiation with α-sarcomeric actin and MHC expression in the constructs. Quantitative PCR analysis showed an expression of myogenic markers in all specimens. Thus, neurotization and addition of bFGF and dexamethasone allow myogenic differentiation of MSC in an axially vascularized in vivo model for the first time. These findings are a new step towards clinical applicability of skeletal muscle tissue engineering and display its potential for regenerative medicine. Franz F. Bitto, Dorothee Klumpp, Claudia Lange, Anja M. Boos, Andreas Arkudas, Oliver Bleiziffer, Raymund E. Horch, Ulrich Kneser, and Justus P. Beier Copyright © 2013 Franz F. Bitto et al. All rights reserved. Mesenchymal Stem Cells and Platelet Gel Improve Bone Deposition within CAD-CAM Custom-Made Ceramic HA Scaffolds for Condyle Substitution Sun, 01 Sep 2013 14:04:31 +0000 Purpose. This study evaluated the efficacy of a regenerative approach using mesenchymal stem cells (MSCs) and CAD-CAM customized pure and porous hydroxyapatite (HA) scaffolds to replace the temporomandibular joint (TMJ) condyle. Methods. Pure HA scaffolds with a 70% total porosity volume were prototyped using CAD-CAM technology to replace the two temporomandibular condyles (left and right) of the same animal. MSCs were derived from the aspirated iliac crest bone marrow, and platelets were obtained from the venous blood of the sheep. Custom-made surgical guides were created by direct metal laser sintering and were used to export the virtual planning of the bone cut lines into the surgical environment. Sheep were sacrificed 4 months postoperatively. The HA scaffolds were explanted, histological specimens were prepared, and histomorphometric analysis was performed. Results. Analysis of the porosity reduction for apposition of newly formed bone showed a statistically significant difference in bone formation between condyles loaded with MSC and condyles without (). The bone ingrowth (BI) relative values of split-mouth comparison (right versus left side) showed a significant difference between condyles with and without MSCs (). Analysis of the test and control sides in the same animal using a split-mouth study design was performed; the condyle with MSCs showed greater bone formation. Conclusion. The split-mouth design confirmed an increment of bone regeneration into the HA scaffold of up to 797% upon application of MSCs. L. Ciocca, D. Donati, S. Ragazzini, B. Dozza, F. Rossi, M. Fantini, A. Spadari, N. Romagnoli, E. Landi, A. Tampieri, A. Piattelli, G. Iezzi, and R. Scotti Copyright © 2013 L. Ciocca et al. All rights reserved. Activation of the ERK1/2 Signaling Pathway during the Osteogenic Differentiation of Mesenchymal Stem Cells Cultured on Substrates Modified with Various Chemical Groups Wed, 28 Aug 2013 09:24:26 +0000 The current study examined the influence of culture substrates modified with the functional groups –OH, –COOH, –NH2, and –CH3 using SAMs technology, in conjunction with TAAB control, on the osteogenic differentiation of rabbit BMSCs. The CCK-8 assay revealed that BMSCs exhibited substrate-dependent cell viability. The cells plated on –NH2- and –OH-modified substrates were well spread and homogeneous, but those on the –COOH- and –CH3-modified substrates showed more rounded phenotype. The mRNA expression of BMSCs revealed that –NH2-modified substrate promoted the mRNA expression and osteogenic differentiation of the BMSCs. The contribution of ERK1/2 signaling pathway to the osteogenic differentiation of BMSCs cultured on the –NH2-modified substrate was investigated in vitro. The –NH2-modified substrate promoted the expression of integrins; the activation of FAK and ERK1/2. Inhibition of ERK1/2 activation by PD98059, a specific inhibitor of the ERK signaling pathway, blocked ERK1/2 activation in a dose-dependent manner, as revealed for expression of Cbfα-1 and ALP. Blockade of ERK1/2 phosphorylation in BMSCs by PD98059 suppressed osteogenic differentiation on chemical surfaces. These findings indicate a potential role for ERK in the osteogenic differentiation of BMSCs on surfaces modified by specific chemical functional groups, indicating that the microenvironment affects the differentiation of BMSCs. This observation has important implications for bone tissue engineering. Bing Bai, Jin He, Yan-Shu Li, Xiu-Mei Wang, Hong-Jun Ai, and Fu-Zhai Cui Copyright © 2013 Bing Bai et al. All rights reserved. The Influence of Chain Microstructure of Biodegradable Copolyesters Obtained with Low-Toxic Zirconium Initiator to In Vitro Biocompatibility Sun, 25 Aug 2013 15:02:16 +0000 Because of the wide use of biodegradable materials in tissue engineering, it is necessary to obtain biocompatible polymers with different mechanical and physical properties as well as degradation ratio. Novel co- and terpolymers of various composition and chain microstructure have been developed and applied for cell culture. The aim of this study was to evaluate the adhesion and proliferation of human chondrocytes to four biodegradable copolymers: lactide-coglycolide, lactide-co--caprolactone, lactide-co-trimethylene carbonate, glycolide-co--caprolactone, and one terpolymer glycolide-colactide-co--caprolactone synthesized with the use of zirconium acetylacetonate as a nontoxic initiator. Chain microstructure of the copolymers was analyzed by means of 1H and 13C NMR spectroscopy and surface properties by AFM technique. Cell adhesion and proliferation were determined by CyQUANT Cell Proliferation Assay Kit. After 4 h the chondrocyte adhesion on the surface of studied materials was comparable to standard TCPS. Cell proliferation occurred on all the substrates; however, among the studied polymers poly(L-lactide-coglycolide) 85 : 15 that characterized the most blocky structure best supported cell growth. Chondrocytes retained the cell membrane integrity evaluated by the LDH release assay. As can be summarized from the results of the study, all the studied polymers are well tolerated by the cells that make them appropriate for human chondrocytes growth. Arkadiusz Orchel, Katarzyna Jelonek, Janusz Kasperczyk, Piotr Dobrzynski, Andrzej Marcinkowski, Elzbieta Pamula, Joanna Orchel, Ireneusz Bielecki, and Anna Kulczycka Copyright © 2013 Arkadiusz Orchel et al. All rights reserved. Engineering Parameters in Bioreactor’s Design: A Critical Aspect in Tissue Engineering Mon, 05 Aug 2013 11:38:11 +0000 Bioreactors are important inevitable part of any tissue engineering (TE) strategy as they aid the construction of three-dimensional functional tissues. Since the ultimate aim of a bioreactor is to create a biological product, the engineering parameters, for example, internal and external mass transfer, fluid velocity, shear stress, electrical current distribution, and so forth, are worth to be thoroughly investigated. The effects of such engineering parameters on biological cultures have been addressed in only a few preceding studies. Furthermore, it would be highly inefficient to determine the optimal engineering parameters by trial and error method. A solution is provided by emerging modeling and computational tools and by analyzing oxygen, carbon dioxide, and nutrient and metabolism waste material transports, which can simulate and predict the experimental results. Discovering the optimal engineering parameters is crucial not only to reduce the cost and time of experiments, but also to enhance efficacy and functionality of the tissue construct. This review intends to provide an inclusive package of the engineering parameters together with their calculation procedure in addition to the modeling techniques in TE bioreactors. Nasim Salehi-Nik, Ghassem Amoabediny, Behdad Pouran, Hadi Tabesh, Mohammad Ali Shokrgozar, Nooshin Haghighipour, Nahid Khatibi, Fatemeh Anisi, Khosrow Mottaghy, and Behrouz Zandieh-Doulabi Copyright © 2013 Nasim Salehi-Nik et al. All rights reserved. Development of Composite Scaffolds for Load-Bearing Segmental Bone Defects Mon, 29 Jul 2013 10:00:20 +0000 The need for a suitable tissue-engineered scaffold that can be used to heal load-bearing segmental bone defects (SBDs) is both immediate and increasing. During the past 30 years, various ceramic and polymer scaffolds have been investigated for this application. More recently, while composite scaffolds built using a combination of ceramics and polymeric materials are being investigated in a greater number, very few products have progressed from laboratory benchtop studies to preclinical testing in animals. This review is based on an exhaustive literature search of various composite scaffolds designed to serve as bone regenerative therapies. We analyzed the benefits and drawbacks of different composite scaffold manufacturing techniques, the properties of commonly used ceramics and polymers, and the properties of currently investigated synthetic composite grafts. To follow, a comprehensive review of in vivo models used to test composite scaffolds in SBDs is detailed to serve as a guide to design appropriate translational studies and to identify the challenges that need to be overcome in scaffold design for successful translation. This includes selecting the animal type, determining the anatomical location within the animals, choosing the correct study duration, and finally, an overview of scaffold performance assessment. Marcello Pilia, Teja Guda, and Mark Appleford Copyright © 2013 Marcello Pilia et al. All rights reserved. Isolation and Characterisation of Mesenchymal Stem Cells from Different Regions of the Human Umbilical Cord Thu, 25 Jul 2013 11:35:38 +0000 Umbilical cords as a source of stem cells are of increasing interest for cell therapies as they present little ethical consideration and are reported to contain immune privileged cells which may be suitable for allogeneic based therapies. Mesenchymal stem cells (MSCs) sourced from several different cord regions, including artery, vein, cord lining, and Wharton’s jelly, are described in the literature. However, no one study has yet isolated and characterised MSCs from all regions of the same cord to determine the most suitable cells for cell based therapeutics. Claire Mennan, Karina Wright, Atanu Bhattacharjee, Birender Balain, James Richardson, and Sally Roberts Copyright © 2013 Claire Mennan et al. All rights reserved. In Vivo Biocompatibility of PLGA-Polyhexylthiophene Nanofiber Scaffolds in a Rat Model Tue, 23 Jul 2013 09:03:32 +0000 Electroactive polymers have applications in tissue engineering as a physical template for cell adhesion and carry electrical signals to improve tissue regeneration. Present study demonstrated the biocompatibility and biodegradability of poly(lactide-co-glycolide)-poly(3-hexylthiophene) (PLGA-PHT) blend electrospun scaffolds in a subcutaneous rat model. The biocompatibility of PLGA-undoped PHT, PLGA-doped PHT, and aligned PLGA-doped PHT nanofibers was evaluated and compared with random PLGA fibers. The animals were sacrificed at 2, 4, and 8 weeks; the surrounding tissue along with the implant was removed to evaluate biocompatibility and biodegradability by histologic analysis and GPC, respectively. Histology results demonstrated that all scaffolds except PLGA-undoped PHT showed decrease in inflammation over time. It was observed that the aligned PLGA-doped PHT fibers elicited moderate response at 2 weeks, which further reduced to a mild response over time with well-organized tissue structure and collagen deposition. The degradation of aligned nanofibers was found to be very slow when compared to random fibers. Further, there was no reduction in the molecular weight of undoped form of PHT throughout the study. These experiments revealed the biocompatibility and biodegradability of PLGA-PHT nanofibers that potentiate it to be used as a biomaterial for various applications. Anuradha Subramanian, Uma Maheswari Krishnan, and Swaminathan Sethuraman Copyright © 2013 Anuradha Subramanian et al. All rights reserved. Three-Dimensional Supermacroporous Carrageenan-Gelatin Cryogel Matrix for Tissue Engineering Applications Sun, 07 Jul 2013 16:12:43 +0000 A tissue-engineered polymeric scaffold should provide suitable macroporous structure similar to that of extracellular matrix which can induce cellular activities and guide tissue regeneration. Cryogelation is a technique in which appropriate monomers or polymeric precursors frozen at sub-zero temperature leads to the formation of supermacroporous cryogel matrices. In this study carrageenan-gelatin (natural polymers) cryogels were synthesized by using glutaraldehyde and 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride and N-hydroxysuccinimide (EDC-NHS) as crosslinking agent at optimum concentrations. Matrices showed large and interconnected pores which were in the range of 60–100 μm diameter. Unconfined compression analysis showed elasticity and physical integrity of all cryogels, as these matrices regained their original length after 90% compressing from the original size. Moreover Young’s modulus was found to be in the range of 4–11 kPa for the dry cryogel sections. These cryogels also exhibited good in vitro degradation capacity at 37 °C within 4 weeks of incubation. Supermacroporous carrageenan-gelatin cryogels showed efficient cell adherence and proliferation of Cos-7 cells which was examined by SEM. PI nuclear stain was used to observe cell-matrix interaction. Cytotoxicity of the scaffolds was checked by MTT assay which showed that cryogels are biocompatible and act as a potential material for tissue engineering and regenerative medicine. Archana Sharma, Sumrita Bhat, Tanushree Vishnoi, Vijayashree Nayak, and Ashok Kumar Copyright © 2013 Archana Sharma et al. All rights reserved. Side-by-Side Comparison of the Biological Characteristics of Human Umbilical Cord and Adipose Tissue-Derived Mesenchymal Stem Cells Sun, 07 Jul 2013 08:08:08 +0000 Both human adipose tissue-derived mesenchymal stem cells (ASCs) and umbilical cord-derived mesenchymal stem cells (UC-MSCs) have been explored as attractive mesenchymal stem cells (MSCs) sources, but very few parallel comparative studies of these two cell types have been made. We designed a side-by-side comparative study by isolating MSCs from the adipose tissue and umbilical cords from mothers delivering full-term babies and thus compared the various biological aspects of ASCs and UC-MSCs derived from the same individual, in one study. Both types of cells expressed cell surface markers characteristic of MSCs. ASCs and UC-MSCs both could be efficiently induced into adipocytes, osteoblasts, and neuronal phenotypes. While there were no significant differences in their osteogenic differentiation, the adipogenesis of ASCs was more prominent and efficient than UC-MSCs. In the meanwhile, ASCs responded better to neuronal induction methods, exhibiting the higher differentiation rate in a relatively shorter time. In addition, UC-MSCs exhibited a more prominent secretion profile of cytokines than ASCs. These results indicate that although ASCs and UC-MSCs share considerable similarities in their immunological phenotype and pluripotentiality, certain biological differences do exist, which might have different implications for future cell-based therapy. Li Hu, Jingqiong Hu, Jiajia Zhao, Jiarong Liu, Weixiang Ouyang, Chao Yang, Niya Gong, Luyang Du, Abhilasha Khanal, and Lili Chen Copyright © 2013 Li Hu et al. All rights reserved. Comparative Study of Various Delivery Methods for the Supply of Alpha-Ketoglutarate to the Neural Cells for Tissue Engineering Wed, 26 Jun 2013 11:20:29 +0000 Delivery of growth factors or bioactive molecules plays an important role in tissue engineering, as the duration to which these are supplied can modulate the cell fate. Thus, the delivery method plays an important role, and the same is presented in this work wherein the exogenous supply of alpha-ketoglutarate (α-KG) gave better results for fast proliferating cells as compared to delivery by microspheres or microspheres incorporated scaffolds which can be used while culturing slow growing cells. All these studies were performed in two dimensional (2D) and three dimensional (3D) setups in which chitosan-gelatin-polypyrrole has been used as 3-D scaffolds. Chitosan and gelatin microspheres alone as well as incorporated in the cryogels were characterized. MTT assay done using neuro-2a cell line showed approximately 42% and 70% increment in cellular proliferation when gelatin and chitosan microspheres were added in a 3-D setup, respectively, as compared to the control. Biochemical analysis of ammonia showed 6-fold reductions in ammonia level in a 3-D setup compared to the control. We also studied the synthesis of a neurotransmitter-like glutamate and found that its concentration increased up to 0.25 mg/ml when the microspheres were added exogenously in a 3-D system. Tanushree Vishnoi and Ashok Kumar Copyright © 2013 Tanushree Vishnoi and Ashok Kumar. All rights reserved. Detergent-Enzymatic Decellularization of Swine Blood Vessels: Insight on Mechanical Properties for Vascular Tissue Engineering Thu, 20 Jun 2013 09:07:45 +0000 Small caliber vessels substitutes still remain an unmet clinical need; few autologous substitutes are available, while synthetic grafts show insufficient patency in the long term. Decellularization is the complete removal of all cellular and nuclear matters from a tissue while leaving a preserved extracellular matrix representing a promising tool for the generation of acellular scaffolds for tissue engineering, already used for various tissues with positive outcomes. The aim of this work is to investigate the effect of a detergent-enzymatic decellularization protocol on swine arteries in terms of cell removal, extracellular matrix preservation, and mechanical properties. Furthermore, the effect of storage at −80°C on the mechanical properties of the tissue is evaluated. Swine arteries were harvested, frozen, and decellularized; histological analysis revealed complete cell removal and preserved extracellular matrix. Furthermore, the residual DNA content in decellularized tissues was far low compared to native one. Mechanical testings were performed on native, defrozen, and decellularized tissues; no statistically significant differences were reported for Young’s modulus, ultimate stress, compliance, burst pressure, and suture retention strength, while ultimate strain and stress relaxation of decellularized vessels were significantly different from the native ones. Considering the overall results, the process was confirmed to be suitable for the generation of acellular scaffolds for vascular tissue engineering. Alessandro F. Pellegata, M. Adelaide Asnaghi, Ilaria Stefani, Anna Maestroni, Silvia Maestroni, Tommaso Dominioni, Sandro Zonta, Gianpaolo Zerbini, and Sara Mantero Copyright © 2013 Alessandro F. Pellegata et al. All rights reserved. Effects of Electromagnetic Fields on Osteogenesis of Human Alveolar Bone-Derived Mesenchymal Stem Cells Wed, 19 Jun 2013 14:31:01 +0000 This study was performed to investigate the effects of extremely low frequency pulsed electromagnetic fields (ELF-PEMFs) on the proliferation and differentiation of human alveolar bone-derived mesenchymal stem cells (hABMSCs). Osteogenesis is a complex series of events involving the differentiation of mesenchymal stem cells to generate new bone. In this study, we examined not merely the effect of ELF-PEMFs on cell proliferation, alkaline phosphatase (ALP) activity, and mineralization of the extracellular matrix but vinculin, vimentin, and calmodulin (CaM) expressions in hABMSCs during osteogenic differentiation. Exposure of hABMSCs to ELF-PEMFs increased proliferation by 15% compared to untreated cells at day 5. In addition, exposure to ELF-PEMFs significantly increased ALP expression during the early stages of osteogenesis and substantially enhanced mineralization near the midpoint of osteogenesis within 2 weeks. ELF-PEMFs also increased vinculin, vimentin, and CaM expressions, compared to control. In particular, CaM indicated that ELF-PEMFs significantly altered the expression of osteogenesis-related genes. The results indicated that ELF-PEMFs could enhance early cell proliferation in hABMSCs-mediated osteogenesis and accelerate the osteogenesis. KiTaek Lim, Jin Hexiu, Jangho Kim, Hoon Seonwoo, Woo Jae Cho, Pill-Hoon Choung, and Jong Hoon Chung Copyright © 2013 KiTaek Lim et al. All rights reserved. Modification of Decellularized Goat-Lung Scaffold with Chitosan/Nanohydroxyapatite Composite for Bone Tissue Engineering Applications Thu, 13 Jun 2013 13:02:15 +0000 Decellularized goat-lung scaffold was fabricated by removing cells from cadaver goat-lung tissue, and the scaffold was modified with chitosan/nanohydroxyapatite composite for the purpose of bone tissue engineering applications. MTT assay with osteoblasts, seeded over the chitosan/nanohydroxyapatite-modified decellularized scaffold, demonstrated significantly higher cell growth as compared to the decellularized scaffold without modification. SEM analysis of cell-seeded scaffold, after incubation for 7 days, represented a good cell adhesion, and the cells spread over the chitosan/nanohydroxyapatite-modified decellularized scaffold. Expression of bone-tissue-specific osteocalcin gene in the osteoblast cells grown over the chitosan/nanohydroxyapatite-modified decellularized scaffold clearly signifies that the cells maintained their osteoblastic phenotype with the chitosan/nanohydroxyapatite-modified decellularized scaffold. Therefore, it can be concluded that the decellularized goat-lung scaffold-modified with chitosan/nanohydroxyapatite composite, may provide enhanced osteogenic potential when used as a scaffold for bone tissue engineering. Sweta K. Gupta, Amit K. Dinda, Pravin D. Potdar, and Narayan C. Mishra Copyright © 2013 Sweta K. Gupta et al. All rights reserved. Preparation, Modification, and Characterization of Alginate Hydrogel with Nano-/Microfibers: A New Perspective for Tissue Engineering Wed, 05 Jun 2013 14:43:05 +0000 We aimed to develop an alginate hydrogel (AH) modified with nano-/microfibers of titanium dioxide (nfTD) and hydroxyapatite (nfHY) and evaluated its biological and chemical properties. Nano-/microfibers of nfTD and nfHY were combined with AH, and its chemical properties were evaluated by FTIR spectroscopy, X-ray diffraction, energy dispersive X-Ray analysis, and the cytocompatibility by the WST-1 assay. The results demonstrate that the association of nfTD and nfHY nano-/microfibers to AH did not modified the chemical characteristics of the scaffold and that the association was not cytotoxic. In the first 3 h of culture with NIH/3T3 cells nfHY AH scaffolds showed a slight increase in cell viability when compared to AH alone or associated with nfTD. However, an increase in cell viability was observed in 24 h when nfTD was associated with AH scaffold. In conclusion our study demonstrates that the combination of nfHY and nfTD nano-/microfibers in AH scaffold maintains the chemical characteristics of alginate and that this association is cytocompatible. Additionally the combination of nfHY with AH favored cell viability in a short term, and the addition of nfTD increased cell viability in a long term. Bianca Palma Santana, Fernanda Nedel, Evandro Piva, Rodrigo Varella de Carvalho, Flávio Fernando Demarco, and Neftali Lenin Villarreal Carreño Copyright © 2013 Bianca Palma Santana et al. All rights reserved. Differentiation of Mesenchymal Stem Cells from Human Umbilical Cord Tissue into Odontoblast-Like Cells Using the Conditioned Medium of Tooth Germ Cells In Vitro Mon, 13 May 2013 14:59:16 +0000 The easily accessible mesenchymal stem cells in the Wharton's jelly of human umbilical cord tissue (hUCMSCs) have excellent proliferation and differentiation potential, but it remains unclear whether hUCMSCs can differentiate into odontoblasts. In this study, mesenchymal stem cells were isolated from the Wharton's jelly of human umbilical cord tissue using the simple method of tissue blocks culture attachment. UCMSC surface marker expression was then evaluated for the isolated cells using flow cytometry. The third-passage hUCMSCs induced by conditioned medium from developing tooth germ cells (TGC-CM) displayed high alkaline phosphatase (ALP) levels (), an enhanced ability to proliferate (), and the presence of mineralized nodules. These effects were not observed in cells treated with regular medium. After induction of hUCMSCs, the results of reverse transcriptional polymerase chain reaction (PCR) indicated that the dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP1) genes were significantly tested. Additionally, dentin sialoprotein (DSP) and DMP1 demonstrated significant levels of staining in an immunofluorescence analysis. In contrast, the control cells failed to display the characteristics of odontoblasts. Taken together, these results suggest that hUCMSCs can be induced to differentiate into odontoblast-like cells with TGC-CM and provide a novel strategy for tooth regeneration research. Tian Xia Li, Jie Yuan, Yan Chen, Li Jie Pan, Chun Song, Liang Jia Bi, and Xiao Hui Jiao Copyright © 2013 Tian Xia Li et al. All rights reserved. Late Adherent Human Bone Marrow Stromal Cells Form Bone and Restore the Hematopoietic Microenvironment In Vivo Wed, 24 Apr 2013 10:15:14 +0000 Bone marrow stromal cells (BMSCs) are a valuable resource for skeletal regenerative medicine because of their osteogenic potential. In spite of the very general term “stem cell,” this population of cells is far from homogeneous, and different BMSCs clones have greatly different phenotypic properties and, therefore, potentially different therapeutic potential. Adherence to a culture flask surface is a primary defining characteristic of BMSCs. We hypothesized that based on the adherence time we could obtain an enriched population of cells with a greater therapeutic potential. We characterized two populations of bone marrow-derived cells, those that adhered by three days (R-cells) and those that did not adhere by three days but did by six days (L-cells). Clones derived from L-cells could be induced into adipogenic, chondrogenic, and osteogenic differentiation in vitro. L-cells appeared to have greater proliferative capacity, as manifested by larger colony diameter and clones with higher CD146 expression. Only clones from L-cells developed bone marrow stroma in vivo. We conclude that the use of late adherence of BMSCs is one parameter that can be used to enrich for cells that will constitute a superior final product for cell therapy in orthopedics. Verônica Fernandes Vianna, Danielle Cabral Bonfim, Amanda dos Santos Cavalcanti, Marco Cury Fernandes, Suzana Assad Kahn, Priscila Ladeira Casado, Inayá Correa Lima, Samuel S. Murray, Elsa J. Brochmann Murray, and Maria Eugenia Leite Duarte Copyright © 2013 Verônica Fernandes Vianna et al. All rights reserved. Comparison of Explant-Derived and Enzymatic Digestion-Derived MSCs and the Growth Factors from Wharton’s Jelly Tue, 09 Apr 2013 10:58:21 +0000 Wharton’s jelly is not only one of the most promising tissue sources for mesenchymal stem cells (MSCs) but also a source of natural growth factors. To prove that we can get both natural growth factors and MSCs from Wharton’s jelly, we compared cellular characteristics and the level of basic fibroblast growth factor (bFGF) from samples using the explant culture method to those derived from the traditional enzymatic culture method. The levels of bFGF were  ng/g on day 3,  ng/g on day 6, and decreased to  ng/g on day 14. The total amount of bFGF released was  ng/g on explant culture. Compared with the traditional enzymatic digestion method, the explant culture method showed a tendency to release higher levels of bFGF in supernatant media for the first week of culture, and the higher cellular yield at passage 0 (/g versus /g, ). In addition, the genes related to mitosis were upregulated in the explant-derived MSCs. Jong Hyun Yoon, Eun Youn Roh, Sue Shin, Nam Hee Jung, Eun Young Song, Ju Young Chang, Byoung Jae Kim, and Hye Won Jeon Copyright © 2013 Jong Hyun Yoon et al. All rights reserved. In Vitro Construction of Scaffold-Free Bilayered Tissue-Engineered Skin Containing Capillary Networks Wed, 27 Mar 2013 15:37:31 +0000 Many types of skin substitutes have been constructed using exogenous materials. Angiogenesis is an important factor for tissue-engineered skin constructs. In this study, we constructed a scaffold-free bilayered tissue-engineered skin containing a capillary network. First, we cocultured dermal fibroblasts with dermal microvascular endothelial cells at a ratio of 2 : 1. A fibrous sheet was formed by the interactions between the fibroblasts and the endothelial cells, and capillary-like structures were observed after 20 days of coculture. Epithelial cells were then seeded on the fibrous sheet to assemble the bilayered tissue. HE staining showed that tissue-engineered skin exhibited a stratified epidermis after 7 days. Immunostaining showed that the epithelium promoted the formation of capillary-like structures. Transmission electron microscopy (TEM) analysis showed that the capillary-like structures were typical microblood vessels. ELISA demonstrated that vascularization was promoted by significant upregulation of vascularization associated growth factors due to interactions among the 3 types of cells in the bilayer, as compared to cocultures of fibroblast and endothelial cells and monocultures. Yuan Liu, Hailang Luo, Xinwen Wang, Akimichi Takemura, Yi Ru Fang, Yan Jin, and Fumihiko Suwa Copyright © 2013 Yuan Liu et al. All rights reserved. Stem Cell Therapy for Lower Extremity Diabetic Ulcers: Where Do We Stand? Mon, 18 Mar 2013 09:16:53 +0000 The impairment of wound healing in diabetic patients is an important clinical problem affecting millions of patients worldwide. Various clinical and basic science studies show that stem cell therapy, as a regenerative medical therapy, can be a good solution. In this paper, we begin with an introduction of the cellular mechanism of the diabetic ulcer. We will then discuss the advantages and limitations of various stem cell therapies that have been under extensive recent study. Mei Yang, Lingling Sheng, Tian R. Zhang, and Qingfeng Li Copyright © 2013 Mei Yang et al. All rights reserved. Trends in Tissue Engineering for Blood Vessels Thu, 08 Nov 2012 15:44:19 +0000 Over the years, cardiovascular diseases continue to increase and affect not only human health but also the economic stability worldwide. The advancement in tissue engineering is contributing a lot in dealing with this immediate need of alleviating human health. Blood vessel diseases are considered as major cardiovascular health problems. Although blood vessel transplantation is the most convenient treatment, it has been delimited due to scarcity of donors and the patient’s conditions. However, tissue-engineered blood vessels are promising alternatives as mode of treatment for blood vessel defects. The purpose of this paper is to show the importance of the advancement on biofabrication technology for treatment of soft tissue defects particularly for vascular tissues. This will also provide an overview and update on the current status of tissue reconstruction especially from autologous stem cells, scaffolds, and scaffold-free cellular transplantable constructs. The discussion of this paper will be focused on the historical view of cardiovascular tissue engineering and stem cell biology. The representative studies featured in this paper are limited within the last decade in order to trace the trend and evolution of techniques for blood vessel tissue engineering. Judee Grace Nemeno-Guanzon, Soojung Lee, Johan Robert Berg, Yong Hwa Jo, Jee Eun Yeo, Bo Mi Nam, Yong-Gon Koh, and Jeong Ik Lee Copyright © 2012 Judee Grace Nemeno-Guanzon et al. All rights reserved. Adipose Tissue Regeneration: A State of the Art Wed, 03 Oct 2012 10:27:55 +0000 Adipose tissue pathologies and defects have always represented a reconstructive challenge for plastic surgeons. In more recent years, several allogenic and alloplastic materials have been developed and used as fillers for soft tissue defects. However, their clinical use has been limited by further documented complications, such as foreign-body reactions potentially affecting function, degradation over time, and the risk for immunogenicity. Tissue-engineering strategies are thus being investigated to develop methods for generating adipose tissue. This paper will discuss the current state of the art in adipose tissue engineering techniques, exploring the biomaterials used, stem cells application, culture strategies, and current regulatory framework that are in use are here described and discussed. Alessandro Casadei, Roberta Epis, Letizia Ferroni, Ilaria Tocco, Chiara Gardin, Eriberto Bressan, Stefano Sivolella, Vincenzo Vindigni, Paolo Pinton, Giuseppe Mucci, and Barbara Zavan Copyright © 2012 Alessandro Casadei et al. All rights reserved. Controlling Self-Renewal and Differentiation of Stem Cells via Mechanical Cues Tue, 02 Oct 2012 12:17:54 +0000 The control of stem cell response in vitro, including self-renewal and lineage commitment, has been proved to be directed by mechanical cues, even in the absence of biochemical stimuli. Through integrin-mediated focal adhesions, cells are able to anchor onto the underlying substrate, sense the surrounding microenvironment, and react to its properties. Substrate-cell and cell-cell interactions activate specific mechanotransduction pathways that regulate stem cell fate. Mechanical factors, including substrate stiffness, surface nanotopography, microgeometry, and extracellular forces can all have significant influence on regulating stem cell activities. In this paper, we review all the most recent literature on the effect of purely mechanical cues on stem cell response, and we introduce the concept of “force isotropy” relevant to cytoskeletal forces and relevant to extracellular loads acting on cells, to provide an interpretation of how the effects of insoluble biophysical signals can be used to direct stem cells fate in vitro. Michele M. Nava, Manuela T. Raimondi, and Riccardo Pietrabissa Copyright © 2012 Michele M. Nava et al. All rights reserved. The Osteogenic Study of Tissue Engineering Bone with BMP2 and BMP7 Gene-Modified Rat Adipose-Derived Stem Cell Thu, 21 Jun 2012 08:33:45 +0000 To evaluate the feasibility and advantages of constructing a novel tissue engineering bone, using 𝛽-tricalcium phosphate (𝛽-TCP) and rat adipose-derived stem cells (ADSCs), modified with BMP2 and BMP7 by lentivirus. In the present study, ADSCs transfected with Lv-BMP2 and Lv-BMP7, alone or together, were seeded on 𝛽-TCP scaffold and cultured in vitro. Based on the results of DNA assay, alkaline phosphatase (ALP) activity, alizarin red staining and osteogenic marker genes expression analysis, the BMP2 and BMP7 genes cotransfection group exhibited a higher degree of osteogenic differentiation in vitro. To investigate the in vivo osteogenesis of the tissue engineering bone, the ADSCs/𝛽-TCP constructs were implanted in rat femurs defects for 6 weeks and studied histomorphology and radiography. The results showed that BMP2 and BMP7 genes cotransfection group dramatically enhanced the efficiency of new bone formation than BMP2 group and BMP7 group in vivo. These results demonstrated that it was advantageous to construct tissue engineering bone using ADSCs cotransfected with BMP2 and BMP7 on 𝛽-TCP, providing a potential way for treating bone defects. Wang Qing, Chen Guang-Xing, Guo Lin, and Yang Liu Copyright © 2012 Wang Qing et al. All rights reserved. Physical Properties and Biocompatibility of a Core-Sheath Structure Composite Scaffold for Bone Tissue Engineering In Vitro Thu, 15 Mar 2012 11:07:38 +0000 Scaffolds play a critical role in the practical realization of bone tissue engineering. The purpose of this study was to assess whether a core-sheath structure composite scaffold possesses admirable physical properties and biocompatibility in vitro. A novel scaffold composed of poly(lactic-co-glycolic acid)/β-tricalcium phosphate (PLGA/β-TCP) skeleton wrapped with Type I collagen via low-temperature deposition manufacturing (LDM) was prepared, and bone mesenchymal stem cells (BMSCs) were used to evaluate cell behavior on the scaffold. PLGA/β-TCP skeleton was chosen as the control group. Physical properties were evaluated by pority ratio, compressive strength, and Young’s modulus. Scanning electron microscope (SEM) was used to study morphology of cells. Hydrophilicity was evaluated by water absorption ratio. Cell proliferation was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (MTT). Osteogenic differentiation of BMSCs was evaluated by alkaline phosphates activity (ALP). The results indicated that physical properties of the novel scaffold were as good as those of the control group, hydrophilicity was observably better (𝑃<0.01) than that of control group, and abilities of proliferation and osteogenic differentiation of BMSCs on novel scaffold were significantly greater (𝑃<0.05) than those of control group, which suggests that the novel scaffold possesses preferable characteristics and have high value in bone tissue engineering. Chuangjian Wang, Guolin Meng, Laquan Zhang, Zuo Xiong, and Jian Liu Copyright © 2012 Chuangjian Wang et al. All rights reserved. Xenogenic Esophagus Scaffolds Fixed with Several Agents: Comparative In Vivo Study of Rejection and Inflammation Thu, 08 Mar 2012 08:38:19 +0000 Most infants with long-gap esophageal atresia receive an esophageal replacement with tissue from stomach or colon, because the native esophagus is too short for true primary repair. Tissue-engineered esophageal conducts could present an attractive alternative. In this paper, circular decellularized porcine esophageal scaffold tissues were implanted subcutaneously into Sprague-Dawley rats. Depending on scaffold cross-linking with genipin, glutaraldehyde, and carbodiimide (untreated scaffolds : positive control; bovine pericardium : gold standard), the number of infiltrating fibroblasts, lymphocytes, macrophages, giant cells, and capillaries was determined to quantify the host response after 1, 9, and 30 days. Decellularized esophagus scaffolds were shown to maintain native matrix morphology and extracellular matrix composition. Typical inflammatory reactions were observed in all implants; however, the cellular infiltration was reduced in the genipin group. We conclude that genipin is the most efficient and best tolerated cross-linking agent to attenuate inflammation and to improve the integration of esophageal scaffolds into its surrounding tissue after implantation. Holger Koch, Cora Graneist, Frank Emmrich, Holger Till, Roman Metzger, Heike Aupperle, Katrin Schierle, Ulrich Sack, and Andreas Boldt Copyright © 2012 Holger Koch et al. All rights reserved. CFP and YFP, but Not GFP, Provide Stable Fluorescent Marking of Rat Hepatic Adult Stem Cells Sun, 30 Mar 2008 00:00:00 +0000 The stable expression of reporter genes in adult stem cells (ASCs) has important applications in stem cell biology. The ability to integrate a noncytotoxic, fluorescent reporter gene into the genome of ASCs with the capability to track ASCs and their progeny is particularly desirable for transplantation studies. The use of fluorescent proteins has greatly aided the investigations of protein and cell function on short-time scales. In contrast, the obtainment of stably expressing cell strains with low variability in expression for studies on longer-time scales is often problematic. We show that this difficulty is partly due to the cytotoxicity of a commonly used reporter, green fluorescent protein (GFP). To avoid GFP-specific toxicity effects during attempts to stably mark a rat hepatic ASC strain and, therefore, obtain stable, long-term fluorescent ASCs, we evaluated cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP), in addition to GFP. Although we were unable to derive stable GFP-expressing strains, stable fluorescent clones (up to 140 doublings) expressing either CFP or YFP were established. When fluorescently marked ASCs were induced to produce differentiated progeny cells, stable fluorescence expression was maintained. This property is essential for studies that track fluorescently marked ASCs and their differentiated progeny in transplantation studies. Rouzbeh R. Taghizadeh and James L. Sherley Copyright © 2008 Rouzbeh R. Taghizadeh and James L. Sherley. All rights reserved.