Stem Cells International The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Differentiation of Equine Mesenchymal Stromal Cells into Cells of Neural Lineage: Potential for Clinical Applications Mon, 24 Nov 2014 12:44:58 +0000 Mesenchymal stromal cells (MSCs) are able to differentiate into extramesodermal lineages, including neurons. Positive outcomes were obtained after transplantation of neurally induced MSCs in laboratory animals after nerve injury, but this is unknown in horses. Our objectives were to test the ability of equine MSCs to differentiate into cells of neural lineage in vitro, to assess differences in morphology and lineage-specific protein expression, and to investigate if horse age and cell passage number affected the ability to achieve differentiation. Bone marrow-derived MSCs were obtained from young and adult horses. Following demonstration of stemness, MSCs were neurally induced and microscopically assessed at different time points. Results showed that commercially available nitrogen-coated tissue culture plates supported proliferation and differentiation. Morphological changes were immediate and all the cells displayed a neural crest-like cell phenotype. Expression of neural progenitor proteins, was assessed via western blot or immunofluorescence. In our study, MSCs generated from young and middle-aged horses did not show differences in their ability to undergo differentiation. The effect of cell passage number, however, is inconsistent and further experiments are needed. Ongoing work is aimed at transdifferentiating these cells into Schwann cells for transplantation into a peripheral nerve injury model in horses. Claudia Cruz Villagrán, Lisa Amelse, Nancy Neilsen, John Dunlap, and Madhu Dhar Copyright © 2014 Claudia Cruz Villagrán et al. All rights reserved. A Comparative View on Human Somatic Cell Sources for iPSC Generation Thu, 06 Nov 2014 09:05:46 +0000 The breakthrough of reprogramming human somatic cells was achieved in 2006 by the work of Yamanaka and Takahashi. From this point, fibroblasts are the most commonly used primary somatic cell type for the generation of induced pluripotent stem cells (iPSCs). Various characteristics of fibroblasts supported their utilization for the groundbreaking experiments of iPSC generation. One major advantage is the high availability of fibroblasts which can be easily isolated from skin biopsies. Furthermore, their cultivation, propagation, and cryoconservation properties are uncomplicated with respect to nutritional requirements and viability in culture. However, the required skin biopsy remains an invasive approach, representing a major drawback for using fibroblasts as the starting material. More and more studies appeared over the last years, describing the reprogramming of other human somatic cell types. Cells isolated from blood samples or urine, as well as more unexpected cell types, like pancreatic islet beta cells, synovial cells, or mesenchymal stromal cells from wisdom teeth, show promising characteristics for a reprogramming strategy. Here, we want to highlight the advantages of keratinocytes from human plucked hair as a widely usable, noninvasive harvesting method for primary material in comparison with other commonly used cell types. Stefanie Raab, Moritz Klingenstein, Stefan Liebau, and Leonhard Linta Copyright © 2014 Stefanie Raab et al. All rights reserved. Phenotypic and Proteomic Characteristics of Human Dental Pulp Derived Mesenchymal Stem Cells from a Natal, an Exfoliated Deciduous, and an Impacted Third Molar Tooth Tue, 14 Oct 2014 12:56:09 +0000 The level of heterogeneity among the isolated stem cells makes them less valuable for clinical use. The purpose of this study was to understand the level of heterogeneity among human dental pulp derived mesenchymal stem cells by using basic cell biology and proteomic approaches. The cells were isolated from a natal (NDPSCs), an exfoliated deciduous (stem cells from human exfoliated deciduous (SHED)), and an impacted third molar (DPSCs) tooth of three different donors. All three stem cells displayed similar features related to morphology, proliferation rates, expression of various cell surface markers, and differentiation potentials into adipocytes, osteocytes, and chondrocytes. Furthermore, using 2DE approach coupled with MALDI-TOF/TOF, we have generated a common 2DE profile for all three stem cells. We found that % of the protein spots were conserved among the three mesenchymal stem cell lines. Sixty-one of these conserved spots were identified by MALDI-TOF/TOF analysis. Classification of the identified proteins based on biological function revealed that structurally important proteins and proteins that are involved in protein folding machinery are predominantly expressed by all three stem cell lines. Some of these proteins may hold importance in understanding specific properties of human dental pulp derived mesenchymal stem cells. Gurler Akpinar, Murat Kasap, Ayca Aksoy, Gokhan Duruksu, Gulcin Gacar, and Erdal Karaoz Copyright © 2014 Gurler Akpinar et al. All rights reserved. Effects of Human Mesenchymal Stem Cells Isolated from Wharton’s Jelly of the Umbilical Cord and Conditioned Media on Skeletal Muscle Regeneration Using a Myectomy Model Tue, 14 Oct 2014 10:32:48 +0000 Skeletal muscle has good regenerative capacity, but the extent of muscle injury and the developed fibrosis might prevent complete regeneration. The in vivo application of human mesenchymal stem cells (HMSCs) of the umbilical cord and the conditioned media (CM) where the HMSCs were cultured and expanded, associated with different vehicles to induce muscle regeneration, was evaluated in a rat myectomy model. Two commercially available vehicles and a spherical hydrogel developed by our research group were used. The treated groups obtained interesting results in terms of muscle regeneration, both in the histological and in the functional assessments. A less evident scar tissue, demonstrated by collagen type I quantification, was present in the muscles treated with HMSCs or their CM. In terms of the histological evaluation performed by ISO 10993-6 scoring, it was observed that HMSCs apparently have a long-term negative effect, since the groups treated with CM presented better scores. CM could be considered an alternative to the in vivo transplantation of these cells, as it can benefit from the local tissue response to secreted molecules with similar results in terms of muscular regeneration. Searching for an optimal vehicle might be the key point in the future of skeletal muscle tissue engineering. T. Pereira, P. A. S. Armada-da Silva, I. Amorim, A. Rêma, A. R. Caseiro, A. Gärtner, M. Rodrigues, M. A. Lopes, P. J. Bártolo, J. D. Santos, A. L. Luís, and A. C. Maurício Copyright © 2014 T. Pereira et al. All rights reserved. Osteogenic Potential of Mouse Adipose-Derived Stem Cells Sorted for CD90 and CD105 In Vitro Mon, 15 Sep 2014 07:18:38 +0000 Adipose tissue-derived stromal cells, termed ASCs, play an important role in regenerative applications. They resemble mesenchymal stem cells owing to their inexhaustibility, general differentiation potential, and plasticity and display a series of cell-specific and cluster-of-differentiation (CD) marker profiles similar to those of other somatic stem cells. Variations in phenotypes or differentiation are intimately associated with CD markers. The purpose of our study was to exhibit distinct populations of ASCs with differing characteristics for osteogenic differentiation. The primary cell batch of murine-derived ASCs was extracted from subcutaneous adipose tissue and the cells were sorted for the expression of the surface protein molecules CD90 and CD105 using flow cytometry. Each cell population sorted for CD90 and CD105 was analyzed for osteogenic potency after cell culture. The results suggested that ASCs exhibit distinct populations with differing characteristics for osteogenic differentiation: unsorted ASCs stimulated comparable mineralized nodule formation as bone marrow stromal cells (BMSCs) in osteogenic medium and viral transfection for BMP2 accelerated the formation of mineralized nodules in CD90 and/or CD105 positive ASCs with observation of decrease in CD105 expression after 14 days. Future studies assessing different immunophenotypes of ASCs should be undertaken to develop cell-based tissue engineering. Maiko Yamamoto, Hidemi Nakata, Jia Hao, Joshua Chou, Shohei Kasugai, and Shinji Kuroda Copyright © 2014 Maiko Yamamoto et al. All rights reserved. Bone Marrow-Derived Multipotent Stromal Cells Attenuate Inflammation in Obliterative Airway Disease in Mouse Tracheal Allografts Wed, 10 Sep 2014 05:45:02 +0000 Obliterative bronchiolitis (OB) remains the most significant cause of death in long-term survival of lung transplantation. Using an established murine heterotopic tracheal allograft model, the effects of different routes of administration of bone marrow-derived multipotent stromal cells (MSCs) on the development of OB were evaluated. Tracheas from BALB/c mice were implanted into the subcutaneous tissue of major histocompatibility complex- (MHC-) disparate C57BL/6 mice. At the time of transplant, bone marrow-derived MSCs were administered either systemically or locally or via a combination of the two routes. The allografts were explanted at various time points after transplantation and were evaluated for epithelial integrity, inflammatory cell infiltration, fibrosis, and luminal obliteration. We found that the most effective route of bone marrow-derived MSC administration is the combination of systemic and local delivery. Treatment of recipient mice with MSCs suppressed neutrophil, macrophage, and T-cell infiltration and reduced fibrosis. These beneficial effects were observed despite lack of significant MSC epithelial engraftment or new epithelial cell generation. Our study suggests that optimal combination of systemic and local delivery of MSCs may ameliorate the development of obliterative airway disease through modulation of immune response. Alicia Casey, Fabian Dirks, Olin D. Liang, Hakima Harrach, Katharina Schuette-Nuetgen, Kristen Leeman, Carla F. Kim, Craig Gerard, and Meera Subramaniam Copyright © 2014 Alicia Casey et al. All rights reserved. Evidence for Transfer of Membranes from Mesenchymal Stem Cells to HL-1 Cardiac Cells Tue, 09 Sep 2014 05:35:10 +0000 This study examined the interaction of mouse bone marrow mesenchymal stem cells (MSC) with cardiac HL-1 cells during coculture by fluorescent dye labeling and then flow cytometry. MSC were layered onto confluent HL-1 cell cultures in a 1 : 4 ratio. MSC gained gap junction permeant calcein from HL-1 cells after 4 hours which was partially reduced by oleamide. After 20 hours, 99% MSC gained calcein, unaffected by oleamide. Double-labeling HL-1 cells with calcein and the membrane dye DiO resulted in transfer of both calcein and DiO to MSC. When HL-1 cells were labeled with calcein and MSC with DiO, MSC gained calcein while HL-1 cells gained DiO. Very little fusion was observed since more than 90% Sca-1 positive MSC gained DiO from HL-1 cells while less than 9% gained gap junction impermeant CMFDA after 20 hours with no Sca-1 transfer to HL-1 cells. Time dependent transfer of membrane DiD was observed from HL-1 cells to MSC (100%) and vice versa (50%) after 20 hours with more limited transfer of CMFDA. These results demonstrate that MSC and HL-1 cells exchange membrane components which may account for some of the beneficial effect of MSC in the heart after myocardial infarction. Robert A. Boomsma and David L. Geenen Copyright © 2014 Robert A. Boomsma and David L. Geenen. All rights reserved. Acupoint Injection of Autologous Stromal Vascular Fraction and Allogeneic Adipose-Derived Stem Cells to Treat Hip Dysplasia in Dogs Mon, 11 Aug 2014 08:51:25 +0000 Stem cells isolated from adipose tissue show great therapeutic potential in veterinary medicine, but some points such as the use of fresh or cultured cells and route of administration need better knowledge. This study aimed to evaluate the effect of autologous stromal vascular fraction (SVF, ) or allogeneic cultured adipose-derived stem cells (ASCs, ) injected into acupuncture points in dogs with hip dysplasia and weak response to drug therapy. Canine ASCs have proliferation and differentiation potential similar to ASCs from other species. After the first week of treatment, clinical evaluation showed marked improvement compared with baseline results in all patients treated with autologous SVF and three of the dogs treated with allogeneic ASCs. On days 15 and 30, all dogs showed improvement in range of motion, lameness at trot, and pain on manipulation of the joints, except for one ASC-treated patient. Positive results were more clearly seen in the SVF-treated group. These results show that autologous SVF or allogeneic ASCs can be safely used in acupoint injection for treating hip dysplasia in dogs and represent an important therapeutic alternative for this type of pathology. Further studies are necessary to assess a possible advantage of SVF cells in treating joint diseases. Camila Marx, Maiele Dornelles Silveira, Isabel Selbach, Ariel Silveira da Silva, Luisa Maria Gomes de Macedo Braga, Melissa Camassola, and Nance Beyer Nardi Copyright © 2014 Camila Marx et al. All rights reserved. Immunological Barriers to Stem Cell Therapy in the Central Nervous System Tue, 05 Aug 2014 09:08:25 +0000 The central nervous system is vulnerable to many neurodegenerative disorders such as Alzheimer’s disease that result in the extensive loss of neuronal cells. Stem cells have the ability to differentiate into many types of cells, which make them ideal for treating such disorders. Although stem cell therapy has shown some promising results in animal models for many brain disorders it has yet to translate into the clinic. A major hurdle to the translation of stem cell therapy into the clinic is the immune response faced by stem cell transplants. Here, we focus on immunological and related hurdles to stem cell therapies for central nervous system disorders. Gregory E. Tullis, Kathleen Spears, and Mark D. Kirk Copyright © 2014 Gregory E. Tullis et al. All rights reserved. Efficacy of Topical Mesenchymal Stem Cell Therapy in the Treatment of Experimental Dry Eye Syndrome Model Thu, 17 Jul 2014 08:59:04 +0000 Purpose. The current study was set out to address the therapeutic efficacy of topically applied mesenchymal stem cells (MSCs) on dry eye syndrome (DES) induced by benzalkonium chloride (BAC) in rats. Methods. Rats were divided into two groups just after establishment of DES. Eye drops containing either bromodeoxyuridine labeled MSCs () or phosphate buffer solution () were topically applied once daily for one week. Schirmer test, break-up time score, ocular surface evaluation tests, and corneal inflammatory index scoring tests were applied to all rats at baseline and after treatment. All rats were sacrificed after one week for histological and electron microscopic analysis. Results. Mean aqueous tear volume and tear film stability were significantly increased in rats treated with MSCs (). Infiltration of bromodeoxyuridine labeled MSCs into the meibomian glands and conjunctival epithelium was observed in MSCs treated rats. Increased number of secretory granules and number of goblet cells were observed in MSCs treated rats. Conclusion. Topical application of MSCs could be a safe and effective method for the treatment of DES and could potentially be used for further clinical research studies. Emrullah Beyazyıldız, Ferda Alpaslan Pınarlı, Özlem Beyazyıldız, Emine Rümeysa Hekimoğlu, Uğur Acar, Muhammed Necati Demir, Aynur Albayrak, Figen Kaymaz, Güngör Sobacı, and Tuncay Delibaşı Copyright © 2014 Emrullah Beyazyıldız et al. All rights reserved. The Secretome of Bone Marrow and Wharton Jelly Derived Mesenchymal Stem Cells Induces Differentiation and Neurite Outgrowth in SH-SY5Y Cells Tue, 15 Jul 2014 06:53:07 +0000 The goal of this study was to determine and compare the effects of the secretome of mesenchymal stem cells (MSCs) isolated from human bone-marrow (BMSCs) and the Wharton jelly surrounding the vein and arteries of the umbilical cord (human umbilical cord perivascular cells (HUCPVCs)) on the survival and differentiation of a human neuroblastoma cell line (SH-SY5Y). For this purpose, SH-SY5Y cells were differentiated with conditioned media (CM) from the MSCs populations referred above. Retinoic acid cultured cells were used as control for neuronal differentiated SH-SY5Y cells. SH-SY5Y cells viability assessment revealed that the secretome of BMSCs and HUCPVCs, in the form of CM, was able to induce their survival. Moreover, immunocytochemical experiments showed that CM from both MSCs was capable of inducing neuronal differentiation of SH-SY5Y cells. Finally, neurite lengths assessment and quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR) analysis demonstrated that CM from BMSCs and HUCPVCs differently induced neurite outgrowth and mRNA levels of neuronal markers exhibited by SH-SY5Y cells. Overall, our results show that the secretome of both BMSCs and HUCPVCs was capable of supporting SH-SY5Y cells survival and promoting their differentiation towards a neuronal phenotype. Ana O. Pires, Andreia Neves-Carvalho, Nuno Sousa, and António J. Salgado Copyright © 2014 Ana O. Pires et al. All rights reserved. Management of Fibrosis: The Mesenchymal Stromal Cells Breakthrough Mon, 14 Jul 2014 09:59:56 +0000 Fibrosis is the endpoint of many chronic inflammatory diseases and is defined by an abnormal accumulation of extracellular matrix components. Despite its slow progression, it leads to organ malfunction. Fibrosis can affect almost any tissue. Due to its high frequency, in particular in the heart, lungs, liver, and kidneys, many studies have been conducted to find satisfactory treatments. Despite these efforts, current fibrosis management therapies either are insufficiently effective or induce severe adverse effects. In the light of these facts, innovative experimental therapies are being investigated. Among these, cell therapy is regarded as one of the best candidates. In particular, mesenchymal stromal cells (MSCs) have great potential in the treatment of inflammatory diseases. The value of their immunomodulatory effects and their ability to act on profibrotic factors such as oxidative stress, hypoxia, and the transforming growth factor-β1 pathway has already been highlighted in preclinical and clinical studies. Furthermore, their propensity to act depending on the microenvironment surrounding them enhances their curative properties. In this paper, we review a large range of studies addressing the use of MSCs in the treatment of fibrotic diseases. The results reported here suggest that MSCs have antifibrotic potential for several organs. Benoît Usunier, Marc Benderitter, Radia Tamarat, and Alain Chapel Copyright © 2014 Benoît Usunier et al. All rights reserved. Stem Cells: Innovations in Clinical Applications Mon, 07 Jul 2014 07:48:08 +0000 The use of mesenchymal stem cells (MSCs) as clinical therapeutics is a relatively new avenue of study for treatment of a variety of diseases. The therapeutic impact of the MSCs is based upon their multiplicities of function and interaction with host tissues. MSCs can be anti-inflammatory, antifibrotic, antimicrobial, and regenerative, all which may improve outcomes in scenarios of damaged tissues and inflammation. Although most studies focus on utilizing MSCs to direct clinical efficacy, it is the ability to orchestrate host response in surrounding tissue that is especially unique and versatile. This orchestration of host response can be applied to a variety of clinical scenarios not only through cell-cell interactions but also through production of bioactive secreted factors. These bioactive factors include small proteins, chemokines, cytokines, and other cellular regulators. These factors have the capacity to induce angiogenesis or blood vessel development, be chemotactic, and induce cellular recruitment. MSCs also have the capacity to differentiate with the implicated environment to regenerate tissue or accommodate host tissue in a cell specific manner. The differentiation cannot only be done in vivo but also can be optimized in vitro prior to in vivo administration, potentiating the versatility of the MSCs and opening avenues for corrective therapy and cell delivery of genes. The differentiation process depends on the environment with which the MSCs are put and results in active communication between the newly administered cells host tissue. Since these properties have been identified, there are a variety of clinical trials and studies being conducted on MSCs ability to treat human disease. This review outlines the potential use of MSCs, the types of tissue, and the innovative applications of MSCs for the treatment of diseases. Morgan T. Sutton and Tracey L. Bonfield Copyright © 2014 Morgan T. Sutton and Tracey L. Bonfield. All rights reserved. A Cocktail Method for Promoting Cardiomyocyte Differentiation from Bone Marrow-Derived Mesenchymal Stem Cells Mon, 23 Jun 2014 08:10:22 +0000 A growing body of evidence supports the argument that bone marrow-derived mesenchymal stem cells (MSCs) can differentiate into cardiomyocyte-like cells in an appropriate cellular environment, but the differentiation rate is low. A cocktail method was designed: we investigated the role of 5-azacytidine (5-aza), salvianolic acid B (SalB), and cardiomyocyte lysis medium (CLM) in inducing MSCs to acquire the phenotypical characteristics of cardiomyocytes. The fourth-passage MSCs were treated with 5-aza, SalB, CLM, 5-aza+salB, 5-aza+CLM, SalB+CLM, and 5-aza+SalB+CLM for 2 weeks. Immunofluorescence results showed that cTnT expression in the 5-aza+salB+CLM group was stronger than other groups. Real-time qPCR and Western blotting analyses showed that cTnT, alpha-cardiac actin, mef-2c, Cx43, and GSK-3beta expression increased while beta-catenin expression decreased. The salB+5-aza+CLM group had the most evident effects. SalB combined with 5-aza and CLM improved cardiomyocyte differentiation from MSCs. In the MSCs differentiation process, the Wnt/beta-catenin signaling pathway had been inhibited. Qing Gao, Maojuan Guo, Xijuan Jiang, Xiantong Hu, Yijing Wang, and Yingchang Fan Copyright © 2014 Qing Gao et al. All rights reserved. A Proposed Quantitative Index for Assessing the Potential Contribution of Reprogramming to Cancer Stem Cell Kinetics Mon, 12 May 2014 13:54:06 +0000 Enrichment of cancer stem cells (CSCs) is thought to be responsible for glioblastoma multiforme (GBM) recurrence after radiation therapy. Simulation results from our agent-based cellular automata model reveal that the enrichment of CSCs may result either from an increased symmetric self-renewal division rate of CSCs or a reprogramming of non-stem cancer cells (CCs) to a stem cell state. Based on plateau-to-peak ratio of the CSC fraction in the tumor following radiation, a downward trend from peak to subsequent plateau (i.e., a plateau-to-peak ratio exceeding 1.0) was found to be inconsistent with increased symmetric division alone and favors instead a strong reprogramming component. The two contributions together are seen to be the product of a dynamic equilibrium between CSCs and CCs that is highly regulated by the kinetics of single cells, including the potential for CCs to reacquire a stem cell state and confer phenotypic plasticity to the population as a whole. We conclude that tumor malignancy can be gauged by a degree of cancer cell plasticity. Xuefeng Gao, J. Tyson McDonald, Mamta Naidu, Philip Hahnfeldt, and Lynn Hlatky Copyright © 2014 Xuefeng Gao et al. All rights reserved. The Efficacy of Mesenchymal Stem Cell Transplantation in Caustic Esophagus Injury: An Experimental Study Sun, 04 May 2014 12:06:24 +0000 Introduction. Ingestion of corrosive substances may lead to stricture formation in esophagus as a late complication. Full thickness injury seems to exterminate tissue stem cells of esophagus. Mesenchymal stem cells (MSCs) can differentiate into specific cell lineages and have the capacity of homing in sites of injury. Aim and Methods. We aimed to investigate the efficacy of MSC transplantation, on prevention of esophageal damage and stricture formation after caustic esophagus injury in rats. 54 rats were allocated into four groups; 4 rats were sacrificed for MSC production. Group 1, untreated controls (: 10). Group 2, membrane labeled MSCs-treated rats (: 20). Group 3, biodistribution of fluorodeoxyglucose labeled MSCs via positron emission tomography (PET) imaging (: 10). Group 4, sham operated (: 10). Standard caustic esophageal burns were created and MSCs were transplanted 24 hours after. All rats were sacrificed at the 21st days. Results. PET scan images revealed the homing behavior of MSCs to the injury site. The histopathology damage score was not significantly different from controls. However, we demonstrated Dil labeled epithelial and muscle cells which were originating from transplanted MSCs. Conclusion. MSC transplantation after caustic esophageal injury may be a helpful treatment modality; however, probably repeated infusions are needed. Murat Kantarcioglu, Bahadir Caliskan, Hakan Demirci, Ozgur Karacalioglu, Murat Kekilli, Zulfikar Polat, Armagan Gunal, Melih Akinci, Cagri Uysal, Sami Eksert, Hasan Gurel, Gurkan Celebi, Ferit Avcu, Ali Ugur Ural, and Sait Bagci Copyright © 2014 Murat Kantarcioglu et al. All rights reserved. Enhanced Adipogenicity of Bone Marrow Mesenchymal Stem Cells in Aplastic Anemia Wed, 30 Apr 2014 08:26:37 +0000 Fatty bone marrow (BM) and defective hematopoiesis are a pathologic hallmark of aplastic anemia (AA). We have investigated adipogenic and osteogenic potential of BM mesenchymal stem cells (BM-MSC) in 10 AA patients (08 males and 02 females) with median age of 37 years (range: 06 to 79 years) and in the same number of age and sex matched controls. It was observed that BM-MSC of AA patients had a morphology, phenotype, and osteogenic differentiation potential similar to control subjects but adipocytes differentiated from AA BM-MSC had a higher density and larger size of lipid droplets and they expressed significantly higher levels of adiponectin and FABP4 genes and proteins as compared to control BM-MSC ( for both). Thus our data shows that AA BM-MSC have enhanced adipogenicity, which may have an important implication in the pathogenesis of the disease. Naresh Kumar Tripathy, Saurabh Pratap Singh, and Soniya Nityanand Copyright © 2014 Naresh Kumar Tripathy et al. All rights reserved. Clinical Applications of Mesenchymal Stem Cells in Chronic Diseases Wed, 30 Apr 2014 07:59:24 +0000 Extraordinary progress in understanding several key features of stem cells has been made in the last ten years, including definition of the niche, and identification of signals regulating mobilization and homing as well as partial understanding of the mechanisms controlling self-renewal, commitment, and differentiation. This progress produced invaluable tools for the development of rational cell therapy protocols that have yielded positive results in preclinical models of genetic and acquired diseases and, in several cases, have entered clinical experimentation with positive outcome. Adult mesenchymal stem cells (MSCs) are nonhematopoietic cells with multilineage potential to differentiate into various tissues of mesodermal origin. They can be isolated from bone marrow and other tissues and have the capacity to extensively proliferate in vitro. Moreover, MSCs have also been shown to produce anti-inflammatory molecules which can modulate humoral and cellular immune responses. Considering their regenerative potential and immunoregulatory effect, MSC therapy is a promising tool in the treatment of degenerative, inflammatory, and autoimmune diseases. It is obvious that much work remains to be done to increase our knowledge of the mechanisms regulating development, homeostasis, and tissue repair and thus to provide new tools to implement the efficacy of cell therapy trials. Andrea Farini, Clementina Sitzia, Silvia Erratico, Mirella Meregalli, and Yvan Torrente Copyright © 2014 Andrea Farini et al. All rights reserved. Mesenchymal Stromal Cells: Novel Methods for Characterization, Understanding Differentiation, and Function Wed, 09 Apr 2014 13:43:20 +0000 Vivek Tanavde, Mohan C. Vemuri, and Radhika Pochampally Copyright © 2014 Vivek Tanavde et al. All rights reserved. Magnetic Nanoparticle Based Nonviral MicroRNA Delivery into Freshly Isolated CD105+ hMSCs Mon, 31 Mar 2014 06:36:12 +0000 Genetic modifications of bone marrow derived human mesenchymal stem cells (hMSCs) using microRNAs (miRs) may be used to improve their therapeutic potential and enable innovative strategies in tissue regeneration. However, most of the studies use cultured hMSCs, although these can lose their stem cell characteristics during expansion. Therefore, we aimed to develop a nonviral miR carrier based on polyethylenimine (PEI) bound to magnetic nanoparticles (MNPs) for efficient miR delivery in freshly isolated hMSCs. MNP based transfection is preferable for genetic modifications in vivo due to improved selectivity, safety of delivery, and reduced side effects. Thus, in this study different miR/PEI and miR/PEI/MNP complex formulations were tested in vitro for uptake efficiency and cytotoxicity with respect to the influence of an external magnetic field. Afterwards, optimized magnetic complexes were selected and compared to commercially available magnetic vectors (Magnetofectamine, CombiMag). We found that all tested transfection reagents had high miR uptake rates (yielded over 60%) and no significant cytotoxic effects. Our work may become crucial for virus-free introduction of therapeutic miRs as well as other nucleic acids in vivo. Moreover, in the field of targeted stem cell therapy nucleic acid delivery prior to transplantation may allowfor initial cell modulation in vitro. Anna Schade, Paula Müller, Evgenya Delyagina, Natalia Voronina, Anna Skorska, Cornelia Lux, Gustav Steinhoff, and Robert David Copyright © 2014 Anna Schade et al. All rights reserved. Migration, Proliferation, and Differentiation of Cord Blood Mesenchymal Stromal Cells Treated with Histone Deacetylase Inhibitor Valproic Acid Sun, 16 Mar 2014 11:45:51 +0000 Mesenchymal stromal cells (MSC) have great potential for cellular therapies as they can be directed to differentiate into certain lineages or to exert paracrine effects at sites of injury. The interactions between stromal cell-derived factor (SDF)-1 and its receptors CXCR4 and CXCR7 play pivotal roles in the migration of MSC to injured tissues. We evaluated whether a histone deacetylase inhibitor valproic acid (VPA) modulates the migration of cord blood (CB-) derived MSC towards SDF-1 and their proliferation and differentiation. We found that in MSC, VPA increased (i) the gene and total protein expression of CXCR4 and CXCR7 and primed migration towards a low gradient of SDF-1, (ii) the gene expression of MMP-2 and secretion and activation of proMMP-2, (iii) the proliferation and gene expression of pluripotency markers SOX2 and Oct-4, and exposure to lower concentrations of VPA (≤5 mM) had no effect on their differentiation to osteocytes and chondrocytes. Thus, our study indicates that VPA enhances the migration of CB MSC towards SDF-1 by increasing the expression of CXCR4, CXCR7, and MMP-2. VPA at low concentrations may be used for ex vivo treatment of MSC to increase their recruitment to sites of injury without compromising their ability to proliferate or differentiate. Leah A. Marquez-Curtis, Yuanyuan Qiu, April Xu, and Anna Janowska-Wieczorek Copyright © 2014 Leah A. Marquez-Curtis et al. All rights reserved. Mesenchymal Stem Cell Biodistribution, Migration, and Homing In Vivo Tue, 11 Mar 2014 12:23:33 +0000 Weian Zhao, Donald G. Phinney, Dominique Bonnet, Massimo Dominici, and Mauro Krampera Copyright © 2014 Weian Zhao et al. All rights reserved. Use of Autologous Mesenchymal Stem Cells Derived from Bone Marrow for the Treatment of Naturally Injured Spinal Cord in Dogs Tue, 25 Feb 2014 12:54:55 +0000 The use of stem cells in injury repair has been extensively investigated. Here, we examined the therapeutic effects of autologous bone marrow mesenchymal stem cells (MSC) transplantation in four dogs with natural traumatic spinal cord injuries. MSC were cultured in vitro, and proliferation rate and cell viability were evaluated. Cell suspensions were prepared and surgically administered into the spinal cord. The animals were clinically evaluated and examined by nuclear magnetic resonance. Ten days after the surgical procedure and MSC transplantation, we observed a progressive recovery of the panniculus reflex and diminished superficial and deep pain response, although there were still low proprioceptive reflexes in addition to a hyperreflex in the ataxic hind limb movement responses. Each dog demonstrated an improvement in these gains over time. Conscious reflex recovery occurred simultaneously with moderate improvement in intestine and urinary bladder functions in two of the four dogs. By the 18th month of clinical monitoring, we observed a remarkable clinical amelioration accompanied by improved movement, in three of the four dogs. However, no clinical gain was associated with alterations in magnetic resonance imaging. Our results indicate that MSC are potential candidates for the stem cell therapy following spinal cord injury. Euler Moraes Penha, Cássio Santana Meira, Elisalva Teixeira Guimarães, Marcus Vinícius Pinheiro Mendonça, Faye Alice Gravely, Cláudia Maria Bahia Pinheiro, Taiana Maria Bahia Pinheiro, Stella Maria Barrouin-Melo, Ricardo Ribeiro-dos-Santos, and Milena Botelho Pereira Soares Copyright © 2014 Euler Moraes Penha et al. All rights reserved. SOX2 Is Regulated Differently from NANOG and OCT4 in Human Embryonic Stem Cells during Early Differentiation Initiated with Sodium Butyrate Wed, 19 Feb 2014 08:10:27 +0000 Transcription factors NANOG, OCT4, and SOX2 regulate self-renewal and pluripotency in human embryonic stem (hES) cells; however, their expression profiles during early differentiation of hES cells are unclear. In this study, we used multiparameter flow cytometric assay to detect all three transcription factors (NANOG, OCT4, and SOX2) simultaneously at single cell level and monitored the changes in their expression during early differentiation towards endodermal lineage (induced by sodium butyrate). We observed at least four distinct populations of hES cells, characterized by specific expression patterns of NANOG, OCT4, and SOX2 and differentiation markers. Our results show that a single cell can express both differentiation and pluripotency markers at the same time, indicating a gradual mode of developmental transition in these cells. Notably, distinct regulation of SOX2 during early differentiation events was detected, highlighting the potential importance of this transcription factor for self-renewal of hES cells during differentiation. Ade Kallas, Martin Pook, Annika Trei, and Toivo Maimets Copyright © 2014 Ade Kallas et al. All rights reserved. Long-Term Quantitative Biodistribution and Side Effects of Human Mesenchymal Stem Cells (hMSCs) Engraftment in NOD/SCID Mice following Irradiation Tue, 11 Feb 2014 12:04:06 +0000 There is little information on the fate of infused mesenchymal stem cells (MSCs) and long-term side effects after irradiation exposure. We addressed these questions using human MSCs (hMSCs) intravenously infused to nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice submitted to total body irradiation (TBI) or local irradiation (abdominal or leg irradiation). The animals were sacrificed 3 to 120 days after irradiation and the quantitative and spatial distribution of hMSCs were studied by polymerase chain reaction (PCR). Following their infusion into nonirradiated animals, hMSCs homed to various tissues. Engraftment depended on the dose of irradiation and the area exposed. Total body irradiation induced an increased hMSC engraftment level compared to nonirradiated mice, while local irradiations increased hMSC engraftment locally in the area of irradiation. Long-term engraftment of systemically administered hMSCs in NOD/SCID mice increased significantly in response to tissue injuries produced by local or total body irradiation until 2 weeks then slowly decreased depending on organs and the configuration of irradiation. In all cases, no tissue abnormality or abnormal hMSCs proliferation was observed at 120 days after irradiation. This work supports the safe and efficient use of MSCs by injection as an alternative approach in the short- and long-term treatment of severe complications after radiotherapy for patients refractory to conventional treatments. Sabine François, Benoit Usunier, Luc Douay, Marc Benderitter, and Alain Chapel Copyright © 2014 Sabine François et al. All rights reserved. Stimulation of Neural Stem Cell Proliferation by Inhibition of Phosphodiesterase 5 Sun, 12 Jan 2014 00:00:00 +0000 The involvement of nitric oxide (NO) and cyclic GMP (cGMP) in neurogenesis has been progressively unmasked over the last decade. Phosphodiesterase 5 (PDE5) specifically degrades cGMP and is highly abundant in the mammalian brain. Inhibition of cGMP hydrolysis by blocking PDE5 is a possible strategy to enhance the first step of neurogenesis, proliferation of neural stem cells (NSC). In this work, we have studied the effect on cell proliferation of 3 inhibitors with different selectivity and potency for PDE5, T0156, sildenafil, and zaprinast, using subventricular zone-(SVZ-) derived NSC cultures. We observed that a short- (6 h) or a long-term (24 h) treatment with PDE5 inhibitors increased SVZ-derived NSC proliferation. Cell proliferation induced by PDE5 inhibitors was dependent on the activation of the mitogen-activated protein kinase (MAPK) and was abolished by inhibitors of MAPK signaling, soluble guanylyl cyclase, and protein kinase G. Moreover, sildenafil neither activated ERK1/2 nor altered levels, suggesting the involvement of pathways different from those activated by T0156 or zaprinast. In agreement with the present results, PDE5 inhibitors may be an interesting therapeutic approach for enhancing the proliferation stage of adult neurogenesis. Ana I. Santos, Bruno P. Carreira, Rui J. Nobre, Caetana M. Carvalho, and Inês M. Araújo Copyright © 2014 Ana I. Santos et al. All rights reserved. Strategies Affording Prevascularized Cell-Based Constructs for Myocardial Tissue Engineering Sun, 05 Jan 2014 13:08:16 +0000 The production of a functional cardiac tissue to be transplanted in the injured area of the infarcted myocardium represents a challenge for regenerative medicine. Most cell-based grafts are unviable because of inadequate perfusion; therefore, prevascularization might be a suitable approach for myocardial tissue engineering. To this aim, cells with a differentiation potential towards vascular and cardiac muscle phenotypes have been cocultured in 2D or 3D appropriate scaffolds. In addition to these basic approaches, more sophisticated strategies have been followed employing mixed-cell sheets, microvascular modules, and inosculation from vascular explants. Technologies exerting spatial control of vascular cells, such as topographical surface roughening and ordered patterning, represent other ways to drive scaffold vascularization. Finally, microfluidic devices and bioreactors exerting mechanical stress have also been employed for high-throughput scaling-up production in order to accelerate muscle differentiation and speeding the endothelialization process. Future research should address issues such as how to optimize cells, biomaterials, and biochemical components to improve the vascular integration of the construct within the cardiac wall, satisfying the metabolic and functional needs of the myocardial tissue. Claudio Muscari, Emanuele Giordano, Francesca Bonafè, Marco Govoni, and Carlo Guarnieri Copyright © 2014 Claudio Muscari et al. All rights reserved. Nonviral Gene Delivery of Growth and Differentiation Factor 5 to Human Mesenchymal Stem Cells Injected into a 3D Bovine Intervertebral Disc Organ Culture System Mon, 23 Dec 2013 09:13:02 +0000 Intervertebral disc (IVD) cell therapy with unconditioned 2D expanded mesenchymal stem cells (MSC) is a promising concept yet challenging to realize. Differentiation of MSCs by nonviral gene delivery of growth and differentiation factor 5 (GDF5) by electroporation mediated gene transfer could be an excellent source for cell transplantation. Human MSCs were harvested from bone marrow aspirate and GDF5 gene transfer was achieved by in vitro electroporation. Transfected cells were cultured as monolayers and as 3D cultures in 1.2% alginate bead culture. MSC expressed GDF5 efficiently for up to 21 days. The combination of GDF5 gene transfer and 3D culture in alginate showed an upregulation of aggrecan and SOX9, two markers for chondrogenesis, and KRT19 as a marker for discogenesis compared to untransfected cells. The cells encapsulated in alginate produced more proteoglycans expressed in GAG/DNA ratio. Furthermore, GDF5 transfected MCS injected into an IVD papain degeneration organ culture model showed a partial recovery of the GAG/DNA ratio after 7 days. In this study we demonstrate the potential of GDF5 transfected MSC as a promising approach for clinical translation for disc regeneration. Christian Bucher, Amiq Gazdhar, Lorin M. Benneker, Thomas Geiser, and Benjamin Gantenbein-Ritter Copyright © 2013 Christian Bucher et al. All rights reserved. Multipotent to Pluripotent Properties of Adult Stem Cells Sun, 15 Dec 2013 18:16:30 +0000 Deepa Bhartiya, Kenneth R. Boheler, and Pranela Rameshwar Copyright © 2013 Deepa Bhartiya et al. All rights reserved. A Review of Stem Cell Translation and Potential Confounds by Cancer Stem Cells Tue, 10 Dec 2013 08:22:28 +0000 Mesenchymal stem cells (MSCs) are multipotent cells found in both fetal and adult tissues. MSCs show promise for cellular therapy for several disorders such as those associated with inflammation. In adults, MSCs primarily reside in the bone marrow (BM) and adipose tissues. In BM, MSCs are found at low frequency around blood vessels and trabecula. MSCs are attractive candidates for regenerative medicine given their ease in harvesting and expansion and their unique ability to bypass the immune system in an allogeneic host. Additionally, MSCs exert pathotropism by their ability to migrate to diseased regions. Despite the “attractive” properties of MSCs, their translation to patients requires indepth research. “Off-the-shelf” MSCs are proposed for use in an allogeneic host. Thus, the transplanted MSCs, when placed in a foreign host, could receive cue from the microenvironment for cellular transformation. An important problem with the use of MSCs involves their ability to facilitate the support of breast and other cancers as carcinoma-associated fibroblasts. MSCs could show distinct effect on each subset of cancer cells. This could lead to untoward effect during MSC therapy since the MSCs would be able to interact with undiagnosed cancer cells, which might be in a dormant state. Based on these arguments, further preclinical research is needed to ensure patient safety with MSC therapy. Here, we discuss the basic biology of MSCs, discuss current applications, and provide evidence why it is important to understand MSC biology in the context of diseased microenvironment for safe application. Bernadette Bibber, Garima Sinha, Aline R. M. Lobba, Steven J. Greco, and Pranela Rameshwar Copyright © 2013 Bernadette Bibber et al. All rights reserved.