Transplantation of human umbilical mesenchymal stem cells from Wharton's jelly after complete transection of the rat spinal cord

Background

Human umbilical mesenchymal stem cells (HUMSCs) isolated from Wharton''s jelly of the umbilical cord can be easily obtained and processed compared with embryonic or bone marrow stem cells. These cells may be a valuable source in the repair of spinal cord injury.

Methodology/Principal Findings

We examine the effects of HUMSC transplantation after complete spinal cord transection in rats. Approximately 5×10⁵ HUMSCs were transplanted into the lesion site. Three groups of rats were implanted with either untreated HUMSCs (referred to as the stem cell group), or HUMSCs treated with neuronal conditioned medium (NCM) for either three days or six days (referred to as NCM-3 and NCM-6 days, respectively). The control group received no HUMSCs in the transected spinal cord. Three weeks after transplantation, significant improvements in locomotion were observed in all the three groups receiving HUMSCs (stem cell, NCM-3 and NCM-6 days groups). This recovery was accompanied by increased numbers of regenerated axons in the corticospinal tract and neurofilament-positive fibers around the lesion site. There were fewer microglia and reactive astrocytes in both the rostral and caudal stumps of the spinal cord in the stem cell group than in the control group. Transplanted HUMSCs survived for 16 weeks and produced large amounts of human neutrophil-activating protein-2, neurotrophin-3, basic fibroblast growth factor, glucocorticoid induced tumor necrosis factor receptor, and vascular endothelial growth factor receptor 3 in the host spinal cord, which may help spinal cord repair.

Conclusions/Significance

Transplantation of HUMSCs is beneficial to wound healing after spinal cord injury in rats.     

Islet-like clusters derived from mesenchymal stem cells in Wharton's Jelly of the human umbilical cord for transplantation to control type 1 diabetes

Background

There is a widespread interest in developing renewable sources of islet-replacement tissue for type I diabetes mellitus. Human mesenchymal cells isolated from the Wharton''s jelly of the umbilical cord (HUMSCs), which can be easily obtained and processed compared with embryonic and bone marrow stem cells, possess stem cell properties. HUMSCs may be a valuable source for the generation of islets.

Methodology and Principal Findings

HUMSCs were induced to transform into islet-like cell clusters in vitro through stepwise culturing in neuron-conditioned medium. To assess the functional stability of the islet-like cell clusters in vivo, these cell clusters were transplanted into the liver of streptozotocin-induced diabetic rats via laparotomy. Glucose tolerance was measured on week 12 after transplantation accompanied with immunohistochemistry and electron microscopy analysis. These islet-like cell clusters were shown to contain human C-peptide and release human insulin in response to physiological glucose levels. Real-time RT-PCR detected the expressions of insulin and other pancreatic β-cell-related genes (Pdx1, Hlxb9, Nkx2.2, Nkx6.1, and Glut-2) in these islet-like cell clusters. The hyperglycemia and glucose intolerance in streptozotocin-induced diabetic rats was significantly alleviated after xenotransplantation of islet-like cell clusters, without the use of immunosuppressants. In addition to the existence of islet-like cell clusters in the liver, some special fused liver cells were also found, which characterized by human insulin and nuclei-positive staining and possessing secretory granules.

Conclusions and Significance

In this study, we successfully differentiate HUMSCs into mature islet-like cell clusters, and these islet-like cell clusters possess insulin-producing ability in vitro and in vivo. HUMSCs in Wharton''s Jelly of the umbilical cord seem to be the preferential source of stem cells to convert into insulin-producing cells, because of the large potential donor pool, its rapid availability, no risk of discomfort for the donor, and low risk of rejection.     

Functional neural differentiation of human adipose tissue-derived stem cells using bFGF and forskolin

Background  

Adult mesenchymal stem cells (MSCs) derived from adipose tissue have the capacity to differentiate into mesenchymal as well as endodermal and ectodermal cell lineage in vitro. We characterized the multipotent ability of human adipose tissue-derived stem cells (hADSCs) as MSCs and investigated the neural differentiation potential of these cells.     

Gravity, a regulation factor in the differentiation of rat bone marrow mesenchymal stem cells

Background

Stem cell therapy has emerged as a potential therapeutic option for tissue engineering and regenerative medicine, but many issues remain to be resolved, such as the amount of seed cells, committed differentiation and the efficiency. Several previous studies have focused on the study of chemical inducement microenvironments. In the present study, we investigated the effects of gravity on the differentiation of bone marrow mesenchymal stem cells (BMSCs) into force-sensitive or force-insensitive cells.

Methods and results

Rat BMSCs (rBMSCs) were cultured under hypergravity or simulated microgravity (SMG) conditions with or without inducement medium. The expression levels of the characteristic proteins were measured and analyzed using immunocytochemical, RT-PCR and Western-blot analyses. After treatment with 5-azacytidine and hypergravity, rBMSCs expressed more characteristic proteins of cardiomyocytes such as cTnT, GATA4 and β-MHC; however, fewer such proteins were seen with SMG. After treating rBMSCs with osteogenic inducer and hypergravity, there were marked increases in the expression levels of ColIA1, Cbfa1 and ALP. Reverse results were obtained with SMG. rBMSCs treated with adipogenic inducer and SMG expressed greater levels of PPARgamma. Greater levels of Cbfa1- or cTnT-positive cells were observed under hypergravity without inducer, as shown by FACS analysis. These results indicate that hypergravity induces differentiation of rBMSCs into force-sensitive cells (cardiomyocytes and osteoblasts), whereas SMG induces force-insensitive cells (adipocytes).

Conclusion

Taken together, we conclude that gravity is an important factor affecting the differentiation of rBMSCs; this provides a new avenue for mechanistic studies of stem cell differentiation and a new approach to obtain more committed differentiated or undifferentiated cells.     

Comparison of transdifferentiated and untransdifferentiated human umbilical mesenchymal stem cells in rats after traumatic brain injury

Transdifferentiated and untransdifferentiated mesenchymal stem cells (MSCs) have shown therapeutic benefits in central nervous system (CNS) injury. However, it is unclear which would be more appropriate for transplantation. To address this question, we transplanted untransdifferentiated human umbilical mesenchymal stem cells (HUMSCs) and transdifferentiated HUMSCs (HUMSC-derived neurospheres, HUMSC-NSs) into a rat model of traumatic brain injury. Cognitive function, cell survival and differentiation, brain tissue morphology and neurotrophin expression were compared between groups. Significant improvements in cognitive function and brain tissue morphology were seen in the HUMSCs group compared with HUMSC-NSs group, which was accompanied by increased neurotrophin expression. Moreover, only few grafted cells survived in both the HUMSCs and HUMSC-NSs groups, with very few of the cells differentiating into neural-like cells. These findings indicate that HUMSCs are more appropriate for transplantation and their therapeutic benefits may be associated with neuroprotection rather than cell replacement.     

In Vitro and In Vivo Magnetic Resonance Tracking of Sinerem-Labeled Human Umbilical Mesenchymal Stromal Cell-Derived Schwann Cells

Tracking of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles-labeled embryonic stem cells, neural stem cells, or adult mesenchymal stem cells in vitro and in vivo by using magnetic resonance (MR) imaging have been reported. However, whether the transdifferentiated cells can be effectively labeled by USPIO has not yet been investigated. The requirement for nerve donor material evokes additional morbidity and inability to generate a sufficiently large number of cells in a short time to hamper the clinic application of Schwann cells (SCs) transplantation. These limitations may be avoided if SCs can be generated from clinically accessible sources, such as bone marrow and umbilical cord. However, a reliable means of inducing the selective differentiation of human mesenchymal stromal cells isolated from the umbilical cord (HUMSCs) into SCs in vitro has not yet been established. In this study, we induce HUMSCs into Schwann-like cells in terms of morphology, phenotype, and function by an improved protocol basing on our previous studies. Furthermore, HUMSCs-derived SCs are labeled efficiently in vitro with ultrasmall superparamagnetic iron oxide contrast agent (USPIO) Sinerem and poly-l-lysine (PLL) without affecting morphology, cell cycle, proliferation, and differentiation ability of the labeled cells between the concentration of 200 to 800 μg/ml. Importantly, when grafted into the intact cerebral cortex and striatum, the survival and migration of these Sinerem-labeled cells were observed using MRI. Our study suggest the effective concentration field for Sinerem use in tracking transdifferentiated HUMSCs, and Sinerem labeling transdifferentiated HUMSCs is feasible, efficient, and safe for MRI tracing following grafting into nervous system.     

Postnatal stem/progenitor cells derived from the dental pulp of adult chimpanzee

Background  

Chimpanzee dental pulp stem/stromal cells (ChDPSCs) are very similar to human bone marrow derived mesenchymal stem/stromal cells (hBMSCs) as demonstrated by the expression pattern of cell surface markers and their multipotent differentiation capability.     

Effect of Oxygen on Cardiac Differentiation in Mouse iPS Cells: Role of Hypoxia Inducible Factor-1 and Wnt/Beta-Catenin Signaling

Background

Disturbances in oxygen levels have been found to impair cardiac organogenesis. It is known that stem cells and differentiating cells may respond variably to hypoxic conditions, whereby hypoxia may enhance stem cell pluripotency, while differentiation of multiple cell types can be restricted or enhanced under hypoxia. Here we examined whether HIF-1alpha modulated Wnt signaling affected differentiation of iPS cells into beating cardiomyocytes.

Objective

We investigated whether transient and sustained hypoxia affects differentiation of cardiomyocytes derived from murine induced pluripotent stem (iPS) cells, assessed the involvement of HIF-1alpha (hypoxia-inducible factor-1alpha) and the canonical Wnt pathway in this process.

Methods

Embryoid bodies (EBs) derived from iPS cells were differentiated into cardiomyocytes and were exposed either to 24 h normoxia or transient hypoxia followed by a further 13 days of normoxic culture.

Results

At 14 days of differentiation, 59±2% of normoxic EBs were beating, whilst transient hypoxia abolished beating at 14 days and EBs appeared immature. Hypoxia induced a significant increase in Brachyury and islet-1 mRNA expression, together with reduced troponin C expression. Collectively, these data suggest that transient and sustained hypoxia inhibits maturation of differentiating cardiomyocytes. Compared to normoxia, hypoxia increased HIF-1alpha, Wnt target and ligand genes in EBs, as well as accumulation of HIF-1alpha and beta-catenin in nuclear protein extracts, suggesting involvement of the Wnt/beta-catenin pathway.

Conclusion

Hypoxia impairs cardiomyocyte differentiation and activates Wnt signaling in undifferentiated iPS cells. Taken together the study suggests that oxygenation levels play a critical role in cardiomyocyte differentiation and suggest that hypoxia may play a role in early cardiogenesis.     

Human Umbilical Mesenchymal Stem Cells-Seeded Bladder Acellular Matrix Grafts for Reconstruction of Bladder Defects in a Canine Model

Background

The goal of this study was to explore the feasibility of utilizing human umbilical mesenchymal stem cells (HUMSCs)-seeded Bladder acellular matrix graft (BAMG) for bladder reconstruction in a canine model.

Methodology/Principal Findings

HUMSCs were isolated from newborn umbilical cords and identified by flow cytometry. Partial cystectomy was performed in the experimental and control group. Bladder defects were repaired with HUMSCs-BAMG in the experimental group and repaired with unseeded-BAMG in control group. The implanted grafts were harvested after surgery. H&E and immunohistochemistry staining were performed to evaluate the regeneration of the bladder defect. Primary cultured HUMSCs displayed typical fibroblast morphology with spindle-shaped. Flow cytometry indicated that these cells were positive for CD105 (97.3%) and CD44 (99%), but negative for CD34 (2.8%), CD31 (2.1%), and CD45 (1.7%). Immunohistochemistry staining showed that a multilayered urothelium and well-developed smooth muscle were observed at 12 weeks in experiment group. In contrast, multilayered urothelial tissues were also observed at 12 weeks in group B, but well-developed smooth muscle bundles were observed.

Conclusions/Significance

Our preliminary results demonstrate that UMSC-seeded BAMGs are superior to unseeded BAMGs to promote the regeneration of bladder defects. Our findings indicated that HUMSCs may be a potential cell source for bladder tissue engineering.     

Differentiation of human umbilical cord Wharton's jelly‐derived mesenchymal stem cells into germ‐like cells in vitro

Recent studies have demonstrated that mesenchymal stem cells could differentiate into germ cells under appropriate conditions. We sought to determine whether human umbilical cord Wharton's jelly‐derived mesenchymal stem cells (HUMSCs) could form germ cells in vitro. HUMSCs were induced to differentiate into germ cells in all‐trans retinoic acid, testosterone and testicular‐cell‐conditioned medium prepared from newborn male mouse testes. HUMSCs formed “tadpole‐like” cells after induction with different reagents and showed both mRNA and protein expression of germ‐cell‐specific markers Oct4 (POUF5), Ckit, CD49_f (α6), Stella (DDPA3), and Vasa (DDX4). Our results may provide a new route for reproductive therapy involving HUMSCs and a novel in vitro model to investigate the molecular mechanisms that regulate the development of the mammalian germ lineage. J. Cell. Biochem. 109: 747–754, 2010. © 2010 Wiley‐Liss, Inc.     

Monolayered mesenchymal stem cells repair scarred myocardium after myocardial infarction

Mesenchymal stem cells are multipotent cells that can differentiate into cardiomyocytes and vascular endothelial cells. Here we show, using cell sheet technology, that monolayered mesenchymal stem cells have multipotent and self-propagating properties after transplantation into infarcted rat hearts. We cultured adipose tissue-derived mesenchymal stem cells characterized by flow cytometry using temperature-responsive culture dishes. Four weeks after coronary ligation, we transplanted the monolayered mesenchymal stem cells onto the scarred myocardium. After transplantation, the engrafted sheet gradually grew to form a thick stratum that included newly formed vessels, undifferentiated cells and few cardiomyocytes. The mesenchymal stem cell sheet also acted through paracrine pathways to trigger angiogenesis. Unlike a fibroblast cell sheet, the monolayered mesenchymal stem cells reversed wall thinning in the scar area and improved cardiac function in rats with myocardial infarction. Thus, transplantation of monolayered mesenchymal stem cells may be a new therapeutic strategy for cardiac tissue regeneration.     

Mesenchymal progenitor cell markers in human articular cartilage: normal distribution and changes in osteoarthritis

Introduction  

Recent findings suggest that articular cartilage contains mesenchymal progenitor cells. The aim of this study was to examine the distribution of stem cell markers (Notch-1, Stro-1 and VCAM-1) and of molecules that modulate progenitor differentiation (Notch-1 and Sox9) in normal adult human articular cartilage and in osteoarthritis (OA) cartilage.     

Individual fates of mesenchymal stem cells <Emphasis Type="Italic">in vitro</Emphasis>

Background  

In vitro cultivated stem cell populations are in general heterogeneous with respect to their expression of differentiation markers. In hematopoietic progenitor populations, this heterogeneity has been shown to regenerate within days from isolated subpopulations defined by high or low marker expression. This kind of plasticity has been suggested to be a fundamental feature of mesenchymal stem cells (MSCs) as well. Here, we study MSC plasticity on the level of individual cells applying a multi-scale computer model that is based on the concept of noise-driven stem cell differentiation.     

Murine mesenchymal progenitor cells from different tissues differentiated via mesenchymal microspheres into the mesodermal direction

Background  

Because specific marker molecules for phenotypical identification of mesenchymal stem and progenitor cells are missing, the assessment of the in vitro-differentiation capacity is a prerequisite to characterize these cells. However, classical differentiation protocols are often cell-consuming and time intensive. Therefore, the establishment of novel strategies for differentiation is one topic of current efforts in stem cell biology. The goal of this study was to demonstrate the practicability of a new differentiation test using plastic adherent cell isolates from different tissues.     

Donor age and cell passage affects differentiation potential of murine bone marrow-derived stem cells

Background  

Bone marrow-derived mesenchymal stem cells (BMSCs) are a widely researched adult stem cell population capable of differentiation into various lineages. Because many promising applications of tissue engineering require cell expansion following harvest and involve the treatment of diseases and conditions found in an aging population, the effect of donor age and ex vivo handling must be understood in order to develop clinical techniques and therapeutics based on these cells. Furthermore, there currently exists little understanding as to how these two factors may be influenced by one another.     

Differential expression level of cytokeratin 8 in cells of the bovine nucleus pulposus complicates the search for specific intervertebral disc cell markers

Introduction  

Development of cell therapies for repairing the intervertebral disc is limited by the lack of a source of healthy human disc cells. Stem cells, particularly mesenchymal stem cells, are seen as a potential source but differentiation strategies are limited by the lack of specific markers that can distinguish disc cells from articular chondrocytes.     

Chromatin remodeling agent trichostatin A: a key-factor in the hepatic differentiation of human mesenchymal stem cells derived of adult bone marrow

Background  

The capability of human mesenchymal stem cells (hMSC) derived of adult bone marrow to undergo in vitro hepatic differentiation was investigated.     

Mechanical strain modulates age-related changes in the proliferation and differentiation of mouse adipose-derived stromal cells

Background  

Previous studies on the effects of aging in human and mouse mesenchymal stem cells suggest that a decline in the number and differentiation potential of stem cells may contribute to aging and aging-related diseases. In this report, we used stromal cells isolated from adipose tissue (ADSCs) of young (8-10 weeks), adult (5 months), and old (21 months) mice to test the hypothesis that mechanical loading modifies aging-related changes in the self-renewal and osteogenic and adipogenic differentiation potential of these cells.