Wharton's jelly-derived cells are a primitive stromal cell population

Somatic stem cell aging and malignant transformation – impact on therapeutic application

Somatic stem cells possess unique properties of self-renewal and plasticity which make them promising candidates for use in tissue engineering and regenerative medicine, in addition to serving as efficient delivery vehicles in site-specific therapy. In the case of therapeutic application, it is essential to isolate and culture stem cells in vitro, to obtain them in sufficient quantities. Although long-term cultivation provides an adequate number of cells, it has been shown that this approach is associated with increased risk of transformation of cultured cells, which presents a significant biological hazard. This article reviews information about biological features and cellular events which occur during long-term cultivation of somatic stem cells, with respect to their safe utilization in potential clinical practice.

An in vitro model for hepatocyte-like cell differentiation from Wharton's jelly derived-mesenchymal stem cells by cell-base aggregates

AIM

The present study investigated the differentiation potential of human Umbilical Cord Mesenchymal Stem Cells (UCMSCs) into hepatic lineage through embryonic body-like aggregate formation in the presence of IGF-1.

BACKGROUND

Cells derived from Wharton's jelly have been reported to display a wide multilineage differentiation potential, showing some similarities to both embryonic (ESC) and mesenchymal stem cells (MSCs).

PATIENTS AND METHODS

Human MSCs isolated from the umbilical cord were plated in 20 μL micro drops. A two-step differentiation protocol was used and the cell aggregates were exposed to the media supplemented with IGF, HGF, oncostatin M, and dexamethasone for 21 days. Immunoperoxidase and immuno-fluorescence were performed for cyrokeratins 18, 19 and albumin. Functional assays were done by periodic acid Schiff (PAS) and indocyanine green.

RESULTS

The expression of cytokeratin 19 was shown to be higher in the cells derived from 3D spheroids compared to those cultured in conventional protocol. They showed a polygonal shape after being exposed to hepatogenic media. Immunostaining demonstrated the expression of cytokeratin-18, 19 and albumin by the differentiated cells. Besides, PAS staining revealed glycogen storage in differentiated cells. Also, a greater number of large size differentiated cells were found at the periphery of the expanded cell aggregates.

CONCLUSION

We established a protocol for UCMSC differentiation into hepatocytes and these cells were morphologically and functionally similar to hepatocytes. Thus, hepatocyte differentiation may be facilitated by the UCMSCs aggregate formation before administration of the differentiation protocols.

Neural differentiation of human umbilical cord mesenchymal stem cells by cerebrospinal fluid

OBJECTIVE

Wharton's jelly (WJ) is the gelatinous connective tissue from the umbilical cord. It is composed of mesenchymal stem cells, collagen fibers, and proteoglycans. The stem cells in WJ have properties that are interesting for research. For example, they are simple to harvest by noninvasive methods, provide large numbers of cells without risk to the donor, the stem cell population may be expanded in vitro, cryogenically stored, thawed, genetically manipulated, and differentiated in vitro. In our study, we investigated the effect of human cerebrospinal fluid (CSF) on neural differentiation of human WJ stem cells.

MATERIAL & METHODS

The cells in passage 2 were induced into neural differentiation with different concentrations of human cerebrospinal fluid. Differentiation along with neural lineage was documented by expression of three neural markers: Nestin, Microtubule-Associated Protein 2 (MAP2), and Glial Fibrillary Astrocytic Protein (GFAP) for 21 days. The expression of the identified genes was confirmed by Reverse Transcriptase PCR (RT-PCR).

RESULTS

Treatment with 100 and 200μg/ml CSF resulted in the expression of GFAP and glial cells marker on days 14 and 21. The expression of neural-specific genes following CSF treatment was dose-dependent and time-dependent. Treatment of the cells with a twofold concentration of CSF, led to the expression of MAP2 on day 14 of induction. No expression of GFAP was detected before day 14 or MAP2 before day 21, which shows the importance of the treatment period. In the present study, expression analysis for the known neural markers: Nestin, GFAP, and MAP2 using RT-PCR were performed. The data demonstrated that CSF could play a role as a strong inducer.

CONCLUSION

RT-PCR showed that cerebrospinal fluid promotes the expression of Nestin, MAP2, and GFAP mRNA in a dose-dependent manner, especially at a concentration of 200 μl/ml. In summary, CSF induces neurogenesis of WJ stem cells that encourages tissue engineering applications with these cells for treatments of neurodegenerative defects and traumatic brain injury.

Investigation of immunomodulatory properties of human Wharton's Jelly-derived mesenchymal stem cells after lentiviral transduction

Human Wharton's Jelly-derived Mesenchymal Stem Cells (hWJ-MSCs) are considered as an alternative for bone-marrow-derived MSCs. These cells have immunosuppressive properties. It was unclear whether the WJ-MSCs would sustain their immunomodulatory characteristics after lentiviral transduction or not. In this study, we evaluated immunomodulatory properties of WJ-MSCs after lentiviral transduction. HWJ-MSCs were transduced with lentiviral particles. Expression of transduced and un-transduced hWJ-MSCs surface molecules and secretion of IL-10, HGF, VEGF and TGF-β was analyzed. Cell proliferation and frequency of CD4(+)CD25(+) CD127(low/neg) Foxp3(+) T regulatory cells was measured. There was no difference between the surface markers and secretion of IL-10, HGF, VEGF and TGF-β in transduced and un-transduced hWJ-MSCs. Both cells inhibited the proliferation of PHA stimulated PBMCs, and improved the frequency of T regulatory cells. These findings suggest that lentiviral transduction does not alter the immunomodulatory function of hWJ-MSCs. However, lentiviral transduction may have a wide range of applications in gene therapy.

Platelet-rich plasma (PRP) promotes fetal mesenchymal stem/stromal cell migration and wound healing process

Numerous studies have shown the presence of high levels of growth factors during the process of healing. Growth factors act by binding to the cell surface receptors and contribute to the subsequent activation of signal transduction mechanisms. Wound healing requires a complex of biological and molecular events that includes attraction and proliferation of different type of cells to the wound site, differentiation and angiogenesis. More specifically, migration of various cell types, such as endothelial cells and their precursors, mesenchymal stem/stromal cells (MSCs) or skin fibroblasts (DFs) plays an important role in the healing process. In recent years, the application of platelet rich plasma (PRP) to surgical wounds and skin ulcerations is becoming more frequent, as it is believed to accelerate the healing process. The local enrichment of growth factors at the wound after PRP application causes a stimulation of tissue regeneration. Herein, we studied: (i) the effect of autologous PRP in skin ulcers of patients of different aetiology, (ii) the proteomic profile of PRP, (iii) the migration potential of amniotic fluid MSCs and DFs in the presence of PRP extract in vitro, (iv) the use of the PRP extract as a substitute for serum in cultivating AF-MSCs. Considering its easy access, PRP may provide a valuable tool in multiple therapeutic approaches.

Current perspectives in mesenchymal stem cell therapies for osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease most commonly occurring in the ageing population. It is a slow progressive condition resulting in the destruction of hyaline cartilage followed by pain and reduced activity. Conventional treatments have little effects on the progression of the condition often leaving surgery as the last option. In the last 10 years tissue engineering utilising mesenchymal stem cells has been emerging as an alternative method for treating OA. Mesenchymal stem cells (MSCs) are multipotent progenitor cells found in various tissues, most commonly bone marrow and adipose tissue. MSCs are capable of differentiating into osteocytes, adipocytes, and chondrocytes. Autologous MSCs can be easily harvested and applied in treatment, but allogenic cells can also be employed. The early uses of MSCs focused on the implantations of cell rich matrixes during open surgeries, resulting in the formation of hyaline-like durable cartilage. More recently, the focus has completely shifted towards direct intra-articular injections where a great number of cells are suspended and injected into affected joints. In this review the history and early uses of MSCs in cartilage regeneration are reviewed and different approaches in current trends are explained and evaluated.

Differentiation of human umbilical cord matrix mesenchymal stem cells into neural-like progenitor cells and maturation into an oligodendroglial-like lineage

Mesenchymal stem cells (MSCs) are viewed as safe, readily available and promising adult stem cells, which are currently used in several clinical trials. Additionally, their soluble-factor secretion and multi-lineage differentiation capacities place MSCs in the forefront of stem cell types with expected near-future clinical applications. In the present work MSCs were isolated from the umbilical cord matrix (Wharton's jelly) of human umbilical cord samples. The cells were thoroughly characterized and confirmed as bona-fide MSCs, presenting in vitro low generation time, high proliferative and colony-forming unit-fibroblast (CFU-F) capacity, typical MSC immunophenotype and osteogenic, chondrogenic and adipogenic differentiation capacity. The cells were additionally subjected to an oligodendroglial-oriented step-wise differentiation protocol in order to test their neural- and oligodendroglial-like differentiation capacity. The results confirmed the neural-like plasticity of MSCs, and suggested that the cells presented an oligodendroglial-like phenotype throughout the differentiation protocol, in several aspects sharing characteristics common to those of bona-fide oligodendrocyte precursor cells and differentiated oligodendrocytes.

Embryonic stem cells conditioned medium enhances Wharton's jelly-derived mesenchymal stem cells expansion under hypoxic condition

Mesenchymal stem cells (MSCs) are accepted as a promising tool for therapeutic purposes. However, low proliferation and early senescence are still main obstacles of MSCs expansion for using as cell-based therapy. Thus, clinical scale of cell expansion is needed to obtain a large number of cells serving for further applications. In this study, we investigated the value of embryonic stem cells conditioned medium (ESCM) for in vitro expansion of Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) as compared to typical culture medium for MSCs, Dulbecco's modified Eagle's medium with 1.0 g/l glucose (DMEM-LG) supplemented with 10 % FBS, under hypoxic condition. The expanded cells from ESCM (ESCM-MSCs) and DMEM-LG (DMEM-MSCs) were characterized for both phenotype and biological activities including proliferation rate, population doubling time, cell cycle distribution and MSCs characteristics. ESCM and DMEM-LG could enhance WJ-MSCs proliferation as 204.66 ± 10.39 and 113.77 ± 7.89 fold increase at day 12, respectively. ESCM-MSCs could express pluripotency genes including Oct-4, Oct-3/4, Nanog, Klf-4, C-Myc and Sox-2 both in early and late passages whereas the downregulations of Oct-4 and Nanog were detected in late passage cells of DMEM-MSCs. The 2 cell populations also showed common MSCs characteristics including normal cell cycle, fibroblastic morphology, cell surface markers expressions (CD29(+), CD44(+), CD90(+), CD34(-), CD45(-)) and differentiation capacities into adipogenic, chondrogenic and osteogenic lineages. Moreover, our results revealed that ESCM exhibited as a rich source of several factors which are required for supportive WJ-MSCs proliferation. In conclusion, ESCM under hypoxic condition could accelerate WJ-MSCs expansion while maintaining their pluripotency properties. Our knowledge provide short term and cost-saving in WJ-MSCs expansion which has benefit to overcome insufficient cell numbers for clinical applications by reusing the discarded cell culture supernates from human ES culture system. Moreover, these findings can also apply for stem cell banking, regenerative medicine and pharmacological applications.

Human Wharton's Jelly-Derived Stem Cells Display Immunomodulatory Properties and Transiently Improve Rat Experimental Autoimmune Encephalomyelitis

Umbilical cord matrix or Wharton's jelly-derived stromal cells (WJ-MSCs) are an easily accessible source of mesenchymal-like stem cells. Recent studies describe a hypoimmunogenic phenotype, multipotent differentiation potential, and trophic support function for WJ-MSCs, with variable clinical benefit in degenerative disease models such as stroke, myocardial infarction, and Parkinson's disease. It remains unclear whether WJ-MSCs have therapeutic value for multiple sclerosis (MS), where autoimmune-mediated demyelination and neurodegeneration need to be halted. In this study, we investigated whether WJ-MSCs possess the required properties to effectively and durably reverse these pathological hallmarks and whether they survive in an inflammatory environment after transplantation. WJ-MSCs displayed a lowly immunogenic phenotype and showed intrinsic expression of neurotrophic factors and a variety of anti-inflammatory molecules. Furthermore, they dose-dependently suppressed proliferation of activated T cells using contact-dependent and paracrine mechanisms. Indoleamine 2,3-dioxygenase 1 was identified as one of the main effector molecules responsible for the observed T-cell suppression. The immune-modulatory phenotype of WJ-MSCs was further enhanced after proinflammatory cytokine treatment in vitro (licensing). In addition to their effect on adaptive immunity, WJ-MSCs interfered with dendritic cell differentiation and maturation, thus directly affecting antigen presentation and therefore T-cell priming. Systemically infused WJ-MSCs potently but transiently ameliorated experimental autoimmune encephalomyelitis (EAE), an animal model for MS, when injected at onset or during chronic disease. This protective effect was paralleled with a reduction in autoantigen-induced T-cell proliferation, confirming their immunomodulatory activity in vivo. Surprisingly, in vitro licensed WJ-MSCs did not ameliorate EAE, indicative of a fast rejection as a result of enhanced immunogenicity. Collectively, we show that WJ-MSCs have trophic support properties and effectively modulate immune cell functioning both in vitro and in the EAE model, suggesting WJ-MSC may hold promise for MS therapy. Future research is needed to optimize survival of stem cells and enhance clinical durability.

A high-efficiency induction of dopaminergic cells from human umbilical mesenchymal stem cells for the treatment of hemiparkinsonian rats

The success rate in previous attempts at transforming human umbilical mesenchymal stem cells (HUMSCs) isolated from Wharton's jelly of the umbilical cord into dopaminergic cells was a mere 12.7%. The present study was therefore initiated to establish a more effective procedure for better yield of dopaminergic cells in such transformation for more effective HUMSC-based therapy for parkinsonism. To examine, in vitro, the effects of enhanced Nurr1 expression in HUMSCs on their differentiation, cells were processed through the three-stage differentiation protocol. The capacity of such cells to synthesize and release dopamine was measured by HPLC. The therapeutic effects of Nurr1-overexppressed HUMSCs were examined in 6-hydroxydopamine-lesioned rats by quantification of rotations in response to amphetamine. Enhanced Nurr1 expression in HUMSCs promoted the transformation into dopaminergic cells in vitro through stepwise culturing in sonic hedgehog, fibroblast growth factor-8, and neuron-conditioned medium. The success rate was about 71%, as determined by immunostaining for tyrosine hydroxylase and around 94 nM dopamine synthesis (intracellular and released into the culture medium), as measured by HPLC. Additionally, transplantation of such cells into the striatum of hemiparkinsonian rats resulted in improvement of their behavioral deficits, as indicated by amphetamine-evoked rotation scores. Viability of the transplanted cells lasted for at least 3 months as verified by positive staining for tyrosine hydroxylase. Nurr1, FGF8, Shh, and NCM can synergistically enhance the differentiation of HUMSCs into dopaminergic cells and may pave the way for HUMSC-based treatments for Parkinson's disease.

Expression of epithelial markers by human umbilical cord stem cells. A topographical analysis

INTRODUCTION

Human umbilical cord stem cells have inherent differentiation capabilities and potential usefulness in regenerative medicine. However, the epithelial differentiation capability and the heterogeneity of these cells have not been fully explored to the date.

METHODS

We analyzed the expression of several undifferentiation and epithelial markers in cells located in situ in different zones of the umbilical cord -in situ analysis- and in primary ex vivo cell cultures of Wharton's jelly stem cells by microarray and immunofluorescence.

RESULTS

Our results demonstrated that umbilical cord cells were heterogeneous and had intrinsic capability to express in situ stem cell markers, CD90 and CD105 and the epithelial markers cytokeratins 3, 4, 7, 8, 12, 13, 19, desmoplakin and zonula occludens 1 as determined by microarray and immunofluorescence, and most of these markers remained expressed after transferring the cells from the in situ to the ex vivo cell culture conditions. However, important differences were detected among some cell types in the umbilical cord, with subvascular zone cells showing less expression of stem cell markers and cells in Wharton's jelly and the amnioblastic zones showing the highest expression of stem cells and epithelial markers.

CONCLUSIONS

These results suggest that umbilical cord mesenchymal cells have intrinsic potential to express relevant epithelial markers, and support the idea that they could be used as alternative cell sources for epithelial tissue engineering.

CD29 of human umbilical cord mesenchymal stem cells is required for expansion of CD34(+) cells

OBJECTIVES

Human umbilical cord mesenchymal stem cells (hUCMSCs) play a critical role in expanding haematopoietic stem cells (HSCs) by providing the essential microenvironment for haematopoiesis. In this study, we sought to investigate whether CD29 of hUCMSCs would play a key role in the ability of hUCMSCs to help expand HSCs in vivo and in vitro.

MATERIAL AND METHODS

To investigate whether CD29 of hUCMSCs would play a key role for the ability of hUCMSCs to expand HSCs, soluble anti-CD29 antibody was added to co-cultures of hUCMSCs and cord blood (CB) CD34(+) cells. It significantly blocked expansion of CB CD34(+) cells induced by hUCMSCs. Using CD29-deficient hUCMSCs models, long-term culture-initiating cell and non-obese diabetic/severe combined immunodeficient disease mouse repopulating cell assay, revealed that CB CD34(+) cells co-cultured with CD29-deficient hUCMSCs only retained the capacity of multipotent differentiation for 5 weeks at the most.

RESULTS

Soluble anti-CD29 antibody significantly blocked expansion of CB CD34(+) cells induced by hUCMSCs. CB CD34(+) cells co-cultured with CD29-deficient hUCMSCs only retained the capacity of multipotent differentiation for 5 weeks at the most.

CONCLUSIONS

CB CD34(+) cells co-cultured with CD29-deficient hUCMSCs gave rise to all major haematopoietic lineages, but failed to engraft long term.

Wharton's jelly mesenchymal stem cells differentiate into retinal progenitor cells

Human Wharton's jelly mesenchymal stem cells were isolated from fetal umbilical cord. Cells were cultured in serum-free neural stem cell-conditioned medium or neural stem cell-conditioned medium supplemented with Dkk-1, a Wnt/β catenin pathway antagonist, and LeftyA, a Nodal signaling pathway antagonist to induce differentiation into retinal progenitor cells. Inverted microscopy showed that after induction, the spindle-shaped or fibroblast-like Wharton's jelly mesenchymal stem cells changed into bulbous cells with numerous processes. Immunofluorescent cytochemical ing and reverse-transcription PCR showed positive expression of retinal progenitor cell markers, Pax6 and Rx, as well as weakly down-regulated nestin expression. These results demonstrate that Wharton's jelly mesenchymal stem cells are capable of differentiating into retinal progenitor cells in vitro.

Application of adipose-derived stem cells in heart disease

Therapy with mesenchymal stem cells is one of the promising tools to improve outcomes after myocardial infarction. Adipose-derived stem cells (ASCs) are an ideal source of mesenchymal stem cells due to their abundance and ease of preparation. Studies in animal models of myocardial infarction have demonstrated the ability of injected ASCs to engraft and differentiate into cardiomyocytes and vasculature cells. ASCs secrete a wide array of angiogenic and anti-apoptotic paracrine factors such as vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor 1. ASCs are capable of enhancing heart function, reducing myocardial infarction, promoting vascularization, and reversing remodeling in the ischemically injured hearts. Furthermore, several ongoing clinical trials using ASCs are producing promising results for heart diseases. This article reviews the isolation, differentiation, immunoregulatory properties, mechanisms of action, animal models, and ongoing clinical trials of ASCs for cardiac disease.

Induction of multipotency in umbilical cord-derived mesenchymal stem cells cultivated under suspension conditions

Due to the limitations in the clinical application of embryonic stem cells (ESC) and induced pluripotent stem cells, mesenchymal stem cells (MSCs) are now much more interesting for cell-based therapy. Although MSCs have several advantages, they are not capable of differentiating to all three embryonic layers (three germ layers) without cultivation under specific induction media. Hence, improvement of MSCs for cell therapy purposes is under intensive study now. In this study, we isolated MSCs from umbilical cord tissue at the single-cell level, by treatment with trypsin, followed by cultivation under suspension conditions to form a colony. These colonies were trypsin resistant, capable of self-renewal differentiation to the three germ layers without any induction, and they were somewhat similar to ESC colonies. The cells were able to grow in both adherent and suspension culture conditions, expressed both the MSCs markers, especially CD105, and the multipotency markers, i.e., SSEA-3, and had a limited lifespan. The cells were expanded under simple culture conditions at the single-cell level and were homogenous. Further and complementary studies are required to understand how trypsin-tolerant mesenchymal stem cells are established. However, our study suggested non-embryonic resources for future cell-based therapy.

Treatment of spinal cord injury: a review of engineering using neural and mesenchymal stem cells

Over time, various treatment modalities for spinal cord injury have been trialed, including pharmacological and nonpharmacological methods. Among these, replacement of the injured neural and paraneural tissues via cellular transplantation of neural and mesenchymal stem cells has been the most attractive. Extensive experimental studies have been done to identify the safety and effectiveness of this transplantation in animal and human models. Herein, we review the literature for studies conducted, with a focus on the human-related studies, recruitment, isolation, and transplantation, of these multipotent stem cells, and associated outcomes.

Effects of lentiviral infection of mesenchymal stem cells on the expression of octamer transcription factor 4

The present study aimed to investigate the effects of lentiviral infection of human umbilical cord mesenchymal stem cells (hUCMSCs) on the expression of octamer transcription factor 4 (Oct4). hUCMSCs were infected with lentivirus carrying the green fluorescent protein gene (GFP) at different multiplicities of infection (MOI), and the optimal MOI was determined by flow cytometry; the proliferation of non-infected and GFP-carrying lentivirus-infected hUCMSCs was evaluated by the MTT assay; and the expression of the Oct4 gene was measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunofluorescence staining in hUCMSCs cultured in vitro for eight weeks. Positive GFP staining of hUCMSCs was estimated at >75% at 48 h following infection with the GFP-carrying lentivirus (MOI = 20); no effect on hUCMSC proliferation was detected by the MTT assay following the infection; immunofluorescence analysis detected positive Oct4 expression in the cell nuclei at two and eight weeks of culture, while the relative expression of Oct4 assessed by qRT-PCR was 0.9075±0.0124. The GFP gene carried by the lentivirus was successfully expressed in hUCMSCs and had no significant effect on Oct4 expression, which lays a solid foundation for future studies investigating gene functions via the use of exogenous markers.

Recellularization potential assessment of Wharton's Jelly-derived endothelial progenitor cells using a human fetal vascular tissue model

Mesenchymal stem cells isolated from Wharton's Jelly have demonstrated an excellent differentiation potential into the endothelial lineage. We hypothesize that endothelial progenitor cells differentiated from Wharton's Jelly-derived mesenchymal stem cells have the potential to repopulate a decellularized vascular bed employed as a biological scaffold. For this purpose, we aimed at investigating the behavior of the endothelial progenitor cells in the decellularized matrix and their potential to repopulate decellularized human vascular tissue. Our main objectives were to differentiate Wharton's Jelly-derived mesenchymal stem cells into endothelial progenitor cells and to obtain a human vascular tissue slice experimental model using the umbilical cord arteries. We employed a decellularization method using enzymatic treatment of the umbilical cord arteries and a recellularization method with the endothelial progenitor cells differentiated from Wharton's Jelly mesenchymal cells in a co-culture system, in order to investigate our hypothesis. The cellular integration within the biological scaffold was determined by using flow cytometry analysis and confirmed by visualization of histological staining as well as fluorescence microscopy. The morphological observations of the recellularized scaffolds revealed the presence of endothelial progenitor cells within the decellularized tissue slices, displaying no degradation of the scaffold's extracellular matrix. The flow cytometry analysis revealed the presence of Wharton's Jelly-derived endothelial progenitor cells population in the decellularized fetal blood vessel scaffold after recellularization. In conclusion, our results have shown that an in vitro human vascular tissue slice experimental model using decellularized human fetal arteries is able to sustain an adequate scaffold for cellular implants.

Positive selection of Wharton's jelly-derived CD105(+) cells by MACS technique and their subsequent cultivation under suspension culture condition: A simple, versatile culturing method to enhance the multipotentiality of mesenchymal stem cells

OBJECTIVE

Wharton's jelly (WJ), an appropriate source of mesenchymal stem cells (MSCs), has been shown to have a wide array of therapeutic applications. However, the WJ-derived MSCs are very heterogeneous and have limited expression of pluripotency markers. Hence, improvement of their culture condition would promote the efficiency of WJ-MSCs. This study aims to employ a simple method of cultivation to obtain WJ-MSCs which express more pluripotency markers.

METHODS

CD105(+) cells were separated by magnetic-associated (activated) cell sorting from umbilical cord mucous tissue. CD105(+) cells were added to Methocult medium diluted in α-minimum essential medium (α-MEM) and seeded in poly(2-hydroxyethyl methacrylate) (poly-HEMA)-coated plates for suspension culture preparation. Differentiation capacity of isolated cells was evaluated in the presence of differentiation-inducing media. The expression of pluripotency markers such as Oct3/4, Nanog, and Sox2 was also analyzed by RT-PCR and western blot techniques. Moreover, immunocytochemistry was performed to detect alpha-smooth muscle actin (antigene) (α-SMA) protein.

RESULTS

WJ-MSCs grew homogeneously and formed colonies when cultured under suspension culture conditions (Non-adhesive WJ-MSCs). They maintained their growth ability in both adherent and suspension cultures for several passages. Non-adhesive WJ-MSCs expressed Oct3/4, Nanog, and Sox2 both at transcriptional and translational levels in comparison to those cultured in conventional adherent cultures. They also expressed α-SMA protein.

DISCUSSION

In this study, we isolated WJ-MSCs using a slightly modified culture condition. Our simple non-genetic method resulted in a homogeneous population of WJ-MSCs, which highly expressed pluripotency markers.

CONCLUSION

In the future, more multipotent WJ-MSCs can be harnessed as a non-embryonic source of MSCs in MSC-based cell therapy.

Are serum-free and xeno-free culture conditions ideal for large scale clinical grade expansion of Wharton's jelly derived mesenchymal stem cells? A comparative study

Introduction

Mesenchymal stromal/stem cells (MSCs) for clinical use have largely been isolated from the bone marrow, although isolation of these cells from many different adult and fetal tissues has been reported as well. One such source of MSCs is the Whartons Jelly (WJ) of the umbilical cord, as it provides an inexhaustible source of stem cells for potential therapeutic use. Isolation of MSCs from the umbilical cord also presents little, if any, ethical concerns, and the process of obtaining the cord tissue is relatively simple with appropriate consent from the donor. However, a great majority of studies rely on the use of bovine serum containing medium for isolation and expansion of these cells, and porcine derived trypsin for dissociating the cells during passages, which may pose potential risks for using these cells in clinical applications. It is therefore of high priority to develop a robust production process by optimizing culture variables to efficiently and consistently generate MSCs that retain desired regenerative and differentiation properties while minimizing risk of disease transmission.

Methods

We have established a complete xeno-free, serum-free culture condition for isolation, expansion and characterization of WJ-MSCs, to eliminate the use of animal components right from initiation of explant culture to clinical scale expansion and cryopreservation. Growth kinetics, in vitro differentiation capacities, immunosuppressive potential and immunophenotypic characterization of the cells expanded in serum-free media have been compared against those cultured under standard fetal bovine serum (FBS) containing medium. We have also compared the colony-forming frequency and genomic stability of the large scale expanded cells. Secretome analysis was performed to compare the angiogenic cytokines and functional angiogenic potency was proved by Matrigel assays.

Results

Results presented in this report identify one such serum-free, xeno-free medium for WJ expansion. Cells cultured in serum-free, xeno-free medium exhibit superior growth kinetics and functional angiogenesis, alongside other MSC characteristics.

Conclusions

We report here that WJ-MSCs cultured and expanded in Mesencult XF, SF Medium retain all necessary characteristics attributed to MSC for potential therapeutic use.

Electronic supplementary material

The online version of this article (doi:10.1186/scrt477) contains supplementary material, which is available to authorized users.

Periosteum derived stem cells for regenerative medicine proposals: Boosting current knowledge

Periosteum is a thin fibrous layer that covers most bones. It resides in a dynamic mechanically loaded environment and provides a niche for pluripotent cells and a source for molecular factors that modulate cell behaviour. Elucidating periosteum regenerative potential has become a hot topic in orthopaedics. This review discusses the state of the art of osteochondral tissue engineering rested on periosteum derived progenitor cells (PDPCs) and suggests upcoming research directions. Periosteal cells isolation, characterization and migration in the site of injury, as well as their differentiation, are analysed. Moreover, the role of cell mechanosensing and its contribution to matrix organization, bone microarchitecture and bone stenght is examined. In this regard the role of periostin and its upregulation under mechanical stress in order to preserve PDPC survival and bone tissue integrity is contemplated. The review also summarized the role of the periosteum in the field of dentistry and maxillofacial reconstruction. The involvement of microRNAs in osteoblast differentiation and in endogenous tissue repair is explored as well. Finally the novel concept of a guided bone regeneration based on the use of periosteum itself as a smart material and the realization of constructs able to mimic the extracellular matrix features is talked out. Additionally, since periosteum can differentiate into insulin producing cells it could be a suitable source in allogenic transplantations. That innovative applications would take advantage from investigations aimed to assess PDPC immune privilege.

Human Wharton's jelly stem cells and its conditioned medium enhance healing of excisional and diabetic wounds

Wound healing is a major problem in diabetic patients and current treatments have met with limited success. We evaluated the treatment of excisional and diabetic wounds using a stem cell isolated from the human umbilical cord Wharton's jelly (hWJSC) that shares unique properties with embryonic and adult mesenchymal stem cells. hWJSCs are non-controversial, available in abundance, hypo-immunogenic, non-tumorigenic, differentiate into keratinocytes, and secrete important molecules for tissue repair. When human skin fibroblasts (CCD) in conventional scratch-wound assays were exposed to hWJSC-conditioned medium (hWJSC-CM) the fibroblasts at the wound edges migrated and completely covered the spaces by day 2 compared to controls. The number of invaded cells, cell viability, total collagen, elastin, and fibronectin levels were significantly greater in the hWJSC-CM treatment arm compared to controls (P < 0.05). When a single application of green fluorescent protein (GFP)-labeled hWJSCs (GFP-hWJSCs) or hWJSC-CM was administered to full-thickness murine excisional and diabetic wounds, healing rates were significantly greater compared to controls (P < 0.05). Wound biopsies collected at various time points showed the presence of green GFP-labeled hWJSCs, positive human keratinocyte markers (cytokeratin, involucrin, filaggrin) and expression of ICAM-1, TIMP-1, and VEGF-A. On histology, the GFP-hWJSCs and hWJSC-CM treated wounds showed reepithelialization, increased vascularity and cellular density and increased sebaceous gland and hair follicle numbers compared to controls. hWJSCs showed increased expression of several miRNAs associated with wound healing compared to CCDs. Our studies demonstrated that hWJSCs enhance healing of excisional and diabetic wounds via differentiation into keratinocytes and release of important molecules.

Ex vivo expansion of hematopoietic stem- and progenitor cells from cord blood in coculture with mesenchymal stroma cells from amnion, chorion, Wharton's jelly, amniotic fluid, cord blood, and bone marrow

In most cases, the amount of hematopoietic stem and progenitor cells (HSPCs) in a single cord blood (CB) unit is not sufficient for allogenic transplantation of adults. Therefore, two CB units are usually required. The ex vivo expansion of HSPCs from CB in coculture with mesenchymal stroma cells (MSCs) might be an alternative. It was investigated, whether bone marrow-derived MSCs, which have to be obtained in an invasive procedure, introduce a further donor and increases the risk of transmissible infectious diseases for the patient can be replaced by MSCs from amnion, chorion, Wharton's jelly, amniotic fluid, and CB, which can be isolated from placental tissue which is readily available when CB is sampled. In a two-step ex vivo coculture mononuclear cells from cryopreserved CB were cultured with different MSC-feederlayers in a medium supplemented with cytokines (stem cell factor, thrombopoietin [TPO], and granulocyte colony-stimulating factor). Expansion rates were analyzed as well, by long-term culture-initiating cell (LTC-IC) and colony-forming unit (CFU) assays, as by measuring CD34(+)- and CD45(+)-cells. Due to the comparably low number of 5×10(2) to 1×10(4) CD34(+)-cells per cm(2) MSC-monolayer, we observed comparably high expansion rates from 80 to 391,000 for CFU, 70 to 313,000 for CD34(+)-, and 200 to 352,000 for CD45(+)-cells. Expansion of LTC-IC was partly observed. Compared to the literature, we found a better expansion rate of CD34(+)-cells with MSCs from all different sources. This is probably due to the comparably low number of 5×10(2) to 1×10 CD34(+)-cells per cm(2) MSC-monolayer we used. Comparably, high expansion rates were observed from 80 to 391,000 for CFUs, 70 to 313,000 for CD34(+)-, and 200 to 352,000 for CD45(+)-cells. However, the expansion of CD34(+)-cells was significantly more effective with MSCs from bone marrow compared to MSCs from amnion, chorion, and Wharton's jelly. The comparison of MSCs from bone marrow with MSCs from CB and amniotic fluid showed no significant difference. We conclude that MSCs from placental tissues might be useful in the expansion of HSPCs, at least if low numbers of CD34(+)-cells per cm(2) MSC-monolayer and a high TPO concentration are implemented in the expansion culture.

Co-transplantation of mesenchymal stromal cells and cord blood cells in treatment of diabetes

BACKGROUND AIMS

Stem cells provide a promising source for treatment of type 1 diabetes, but the treatment strategy and mechanism remain unclear. The aims of this study were to investigate whether co-transplantation of umbilical cord-derived mesenchymal stromal cells (UC-MSCs) and cord blood mononuclear cells (CB-MNCs) could reverse hyperglycemia in type 1 diabetic mice and to determine the appropriate ratio for co-transplantation. The treatment mechanism was also studied.

METHODS

A simple and efficient isolation method was developed to generate qualified UC-MSCs. UC-MSCs and CB-MNCs were then transplanted into type 1 diabetic mice at different ratios (UC-MSCs to CB-MNCs = 1:1, 1:4, 1:10) to observe the change in blood glucose concentration. Histology, immunohistochemistry, and human Alu polymerase chain reaction assay were performed to evaluate for the presence of donor-derived cells and the repair of endogenous islets. We also induced UC-MSCs into islet-like cells under specific culture conditions to determine their differentiate potential in vitro.

RESULTS

Co-transplantation of UC-MSCs and CB-MNCs at a ratio of 1:4 effectively reversed hyperglycemia in diabetic mice. The detection of human Alu sequence indicated that the engraftment of donor-derived cells had homed into the recipient's pancreas and kidney. Although neither human insulin nor human nuclei antigen was detected in the regenerated pancreas, UC-MSCs could differentiate into insulin-secreted cells in vitro.

CONCLUSIONS

Co-transplantation of UC-MSCs and CB-MNCs at a ratio of 1:4 could efficiently reverse hyperglycemia and repair pancreatic tissue.

Assessment of umbilical cord tissue as a source of mesenchymal stem cell/endothelial cell mixtures for bone regeneration

AIM

To enumerate and characterize mesenchymal stem cells (MSCs) and endothelial cells (ECs) in umbilical cord (UC) tissue digests.

MATERIALS & METHODS

Cultured UC cells were characterized phenotypically, and functionally by using 48-gene arrays. Native MSCs and ECs were enumerated using flow cytometry.

RESULTS

Compared with bone marrow (BM) MSCs, UC MSCs displayed significantly lower (range 4-240-fold) basal levels of bone-related transcripts, but their phenotypes were similar (CD73⁺, CD105⁺, CD90⁺, CD45⁻ and CD31⁻). UC MSCs responded well to osteogenic induction, but day 21 postinduction levels remained below those achieved by BM MSCs. The total yield of native UC MSCs (CD90⁺, CD45⁻ and CD235α⁻) and ECs (CD31⁺, CD45⁻ and CD235α⁻) exceeded 150 and 15 million cells/donation, respectively. Both UC MSCs and ECs expressed CD146.

CONCLUSION

While BM MSCs are more predisposed to osteogenesis, UC tissue harbors large numbers of MSCs and ECs; such minimally manipulated 'off-the-shelf' cellular mixtures can be used for regenerating bone in patients with compromised vascular supply.

The assessment of CD146-based cell sorting and telomere length analysis for establishing the identity of mesenchymal stem cells in human umbilical cord

Adult stem cells are characterised by longer telomeres compared to mature cells from the same tissue. In this study, candidate CD146 (+) umbilical cord (UC) mesenchymal stem cells (MSCs) were purified by cell sorting from UC tissue digests and their telomere lengths were measured in comparison to donor-matched CD146-negative fraction. UC tissue fragments were enzymatically treated with collagenase and the cells were used for cell sorting, colony-forming fibroblast (CFU-F) assay or for long-term MSC cultivation. Telomere lengths were measured by qPCR in both culture-expanded MSCs and candidate native UC MSCs. Immunohistochemistry was undertaken to study the topography of CD146 (+) cells. Culture-expanded UC MSCs had a stable expression of CD73, CD90 and CD105, whereas CD146 declined in later passages which correlated with the shortening of telomeres in the same cultures. In five out of seven donors, telomeres in candidate native UC MSCs (CD45 (-)CD235α (-)CD31 (-)CD146 (+)) were longer compared to donor-matched CD146 (-) population (CD45 (-)CD235α (-)CD31 (-)CD146 (-)). The frequency of CD45 (-)CD235α (-)CD31 (-)CD146 (+) cells measured by flow cytometry was ~1000-fold above that of CFU-Fs (means 10.4% and 0.01%, respectively). CD146 (+) cells were also abundant in situ having a broad topography including high levels of positivity in muscle areas in addition to vessels. Although qPCR-based telomere length analysis in sorted populations could be limited in its sensitivity, very high frequency of CD146 (+) cells in UC tissue suggests that CD146 expression alone is unlikely to be sufficient to identify and purify native MSCs from the UC tissue.

Using human umbilical cord cells for tissue engineering: a comparison with skin cells

The epithelial cells and Wharton׳s jelly cells (WJC) from the human umbilical cord have yet to be extensively studied in respect to their capacity to generate tissue-engineered substitutes for clinical applications. Our reconstruction strategy, based on the self-assembly approach of tissue engineering, allows the production of various types of living human tissues such as skin and cornea from a wide range of cell types originating from post-natal tissue sources. Here we placed epithelial cells and WJC from the umbilical cord in the context of a reconstructed skin substitute in combination with skin keratinocytes and fibroblasts. We compared the ability of the epithelial cells from both sources to generate a stratified, differentiated skin-like epithelium upon exposure to air when cultured on the two stromal cell types. Conversely, the ability of the WJC to behave as dermal fibroblasts, producing extracellular matrix and supporting the formation of a differentiated epithelium for both types of epithelial cells, was also investigated. Of the four types of constructs produced, the combination of WJC and keratinocytes was the most similar to skin engineered from dermal fibroblasts and keratinocytes. When cultured on dermal fibroblasts, the cord epithelial cells were able to differentiate in vitro into a stratified multilayered epithelium expressing molecules characteristic of keratinocyte differentiation after exposure to air, and maintaining the expression of keratins K18 and K19, typical of the umbilical cord epithelium. WJC were able to support the growth and differentiation of keratinocytes, especially at the early stages of air-liquid culture. In contrast, cord epithelial cells cultured on WJC did not form a differentiated epidermis when exposed to air. These results support the premise that the tissue from which cells originate can largely affect the properties and homoeostasis of reconstructed substitutes featuring both epithelial and stromal compartments.

The assessment of CD146-based cell sorting and telomere length analysis for establishing the identity of mesenchymal stem cells in human umbilical cord

Adult stem cells are characterised by longer telomeres compared to mature cells from the same tissue. In this study, candidate CD146 ⁺ umbilical cord (UC) mesenchymal stem cells (MSCs) were purified by cell sorting from UC tissue digests and their telomere lengths were measured in comparison to donor-matched CD146-negative fraction.

UC tissue fragments were enzymatically treated with collagenase and the cells were used for cell sorting, colony-forming fibroblast (CFU-F) assay or for long-term MSC cultivation. Telomere lengths were measured by qPCR in both culture-expanded MSCs and candidate native UC MSCs. Immunohistochemistry was undertaken to study the topography of CD146 ⁺ cells.

Culture-expanded UC MSCs had a stable expression of CD73, CD90 and CD105, whereas CD146 declined in later passages which correlated with the shortening of telomeres in the same cultures. In five out of seven donors, telomeres in candidate native UC MSCs (CD45 ^-CD235α ^-CD31 ^-CD146 ⁺) were longer compared to donor-matched CD146 ^- population (CD45 ^-CD235α ^-CD31 ^-CD146 ^-). The frequency of CD45 ^-CD235α ^-CD31 ^-CD146 ⁺ cells measured by flow cytometry was ~1000-fold above that of CFU-Fs (means 10.4% and 0.01%, respectively). CD146 ⁺ cells were also abundant in situ having a broad topography including high levels of positivity in muscle areas in addition to vessels.

Although qPCR-based telomere length analysis in sorted populations could be limited in its sensitivity, very high frequency of CD146 ⁺ cells in UC tissue suggests that CD146 expression alone is unlikely to be sufficient to identify and purify native MSCs from the UC tissue.

Preeclampsia enhances neuroglial marker expression in umbilical cord Wharton's jelly-derived mesenchymal stem cells

OBJECTIVE

The aim of the study was to compare the neuroglial phenotype of Wharton's jelly-derived mesenchymal stem cells (WJ-MSC) from pregnancies complicated with preeclampsia and gestational age (GA)-matched controls.

METHODS

WJ-MSC were isolated from umbilical cords from both groups and analyzed for the cell surface expression of MSC markers and the gene and protein expression of neuroglial markers.

RESULTS

All WJ cells were highly positive for the MSC markers CD105, CD90 and CD73, but negative for markers specific for hematopoietic (CD34) and immunological cells (CD45, CD14, CD19 and HLA-DR). WJ-MSC from both groups expressed neuroglial markers (MAP-2, GFAP, MBP, Musashi-1 and Nestin) at the mRNA and protein level. The protein expressions of neuronal (MAP-2) and oligodendrocytic (MBP) markers were significantly increased in WJ-MSC from preeclampsia versus GA-matched controls.

CONCLUSIONS

WJ-MSC from preeclamptic patients are possibly more committed to neuroglial differentiation through the activation of pathways involved both in the pathophysiology of the disease and in neurogenesis.

Human umbilical cord-derived mesenchymal stem cells do not undergo malignant transformation during long-term culturing in serum-free medium

BACKGROUND

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are in the foreground as a preferable application for treating diseases. However, the safety of hUC-MSCs after long-term culturing in vitro in serum-free medium remains unclear.

METHODS

hUC-MSCs were separated by adherent tissue culture. hUC-MSCs were cultured in serum-free MesenCult-XF medium and FBS-bases DMEM complete medium. At the 1st, 3rd, 5th, 8th, 10th, and 15th passage, the differentiation of MSCs into osteogenic, chondrogenic, and adipogenic cells was detected, and MTT, surface antigens were measured. Tumorigenicity was analyzed at the 15th passage. Conventional karyotyping was performed at passage 0, 8, and 15. The telomerase activity of hUC-MSCs at passage 1-15 was analyzed.

RESULTS

Flow cytometry analysis showed that very high expression was detected for CD105, CD73, and CD90 and very low expression for CD45, CD34, CD14, CD79a, and HLA-DR. MSCs could differentiate into osteocytes, chondrocytes, and adipocytes in vitro. There was no obvious chromosome elimination, displacement, or chromosomal imbalance as determined from the guidelines of the International System for Human Cytogenetic Nomenclature. Telomerase activity was down-regulated significantly when the culture time was prolonged. Further, no tumors formed in rats injected with hUC-MSCs (P15) cultured in serum-free and in serum-containing conditions.

CONCLUSION

Our data showed that hUC-MSCs met the International Society for Cellular Therapy standards for conditions of long-term in vitro culturing at P15. Since hUC-MSCs can be safely expanded in vitro and are not susceptible to malignant transformation in serum-free medium, these cells are suitable for cell therapy.

Treatment of osteoarthritis with mesenchymal stem cells

Osteoarthritis (OA) is one of the most prevalent joint diseases with prominent symptoms affecting the daily life of millions of middle aged and elderly people. Despite this, there are no successful medical interventions that can prevent the progressive destruction of OA joints. The onset of pathological changes in OA is associated with deviant activity of mesenchymal stem cells (MSCs), the multipotent precursors of connective tissue cells that reside in joints. Current therapies for OA have resulted in poor clinical outcomes without repairing the damaged cartilage. Intra-articular delivery of culture-expanded MSCs has opened new avenues of OA treatment. Pre-clinical and clinical trials demonstrated the feasibility, safety, and efficacy of MSC therapy. The Wnt/β-catenin, bone morphogenetic protein 2, Indian hedgehog, and Mitogen-activated protein kinase signaling pathways have been demonstrated to be involved in OA and the mechanism of action of MSC therapies.

Current status of cell-mediated regenerative therapies for human spinal cord injury

During the past decade, significant advances have been made in refinements for regenerative therapies following human spinal cord injury (SCI). Positive results have been achieved with different types of cells in various clinical studies of SCI. In this review, we summarize recently-completed clinical trials using cell-mediated regenerative therapies for human SCI, together with ongoing trials using neural stem cells. Specifically, clinical studies published in Chinese journals are included. These studies show that current transplantation therapies are relatively safe, and have provided varying degrees of neurological recovery. However, many obstacles exist, hindering the introduction of a specific clinical therapy, including complications and their causes, selection of the target population, and optimization of transplantation material. Despite these and other challenges, with the collaboration of research groups and strong support from various organizations, cell-mediated regenerative therapies will open new perspectives for SCI treatment.

Neurotrauma and mesenchymal stem cells treatment: From experimental studies to clinical trials

Mesenchymal stem cell (MSC) therapy has attracted the attention of scientists and clinicians around the world. Basic and pre-clinical experimental studies have highlighted the positive effects of MSC treatment after spinal cord and peripheral nerve injury. These effects are believed to be due to their ability to differentiate into other cell lineages, modulate inflammatory and immunomodulatory responses, reduce cell apoptosis, secrete several neurotrophic factors and respond to tissue injury, among others. There are many pre-clinical studies on MSC treatment for spinal cord injury (SCI) and peripheral nerve injuries. However, the same is not true for clinical trials, particularly those concerned with nerve trauma, indicating the necessity of more well-constructed studies showing the benefits that cell therapy can provide for individuals suffering the consequences of nerve lesions. As for clinical trials for SCI treatment the results obtained so far are not as beneficial as those described in experimental studies. For these reasons basic and pre-clinical studies dealing with MSC therapy should emphasize the standardization of protocols that could be translated to the clinical set with consistent and positive outcomes. This review is based on pre-clinical studies and clinical trials available in the literature from 2010 until now. At the time of writing this article there were 43 and 36 pre-clinical and 19 and 1 clinical trials on injured spinal cord and peripheral nerves, respectively.

Umbilical cord-derived mesenchymal stem cells: Their advantages and potential clinical utility

Human umbilical cord (UC) is a promising source of mesenchymal stem cells (MSCs). Apart from their prominent advantages, such as a painless collection procedure and faster self-renewal, UC-MSCs have shown the ability to differentiate into three germ layers, to accumulate in damaged tissue or inflamed regions, to promote tissue repair, and to modulate immune response. There are diverse protocols and culture methods for the isolation of MSCs from the various compartments of UC, such as Wharton’s jelly, vein, arteries, UC lining and subamnion and perivascular regions. In this review, we give a brief introduction to various compartments of UC as a source of MSCs and emphasize the potential clinical utility of UC-MSCs for regenerative medicine and immunotherapy.

Umbilical cord mesenchymal stem cells: the new gold standard for mesenchymal stem cell-based therapies?

Due to their self-renewal capacity, multilineage differentiation potential, paracrine effects, and immunosuppressive properties, mesenchymal stromal cells (MSCs) are an attractive and promising tool for regenerative medicine. MSCs can be isolated from various tissues but despite their common immunophenotypic characteristics and functional properties, source-dependent differences in MSCs properties have recently emerged and lead to different clinical applications. Considered for a long time as a medical waste, umbilical cord appears these days as a promising source of MSCs. Several reports have shown that umbilical cord-derived MSCs are more primitive, proliferative, and immunosuppressive than their adult counterparts. In this review, we aim at synthesizing the differences between umbilical cord MSCs and MSCs from other sources (bone marrow, adipose tissue, periodontal ligament, dental pulp,…) with regard to their proliferation capacity, proteic and transcriptomic profiles, and their secretome involved in their regenerative, homing, and immunomodulatory capacities. Although umbilical cord MSCs are until now not particularly used as an MSC source in clinical practice, accumulating evidence shows that they may have a therapeutic advantage to treat several diseases, especially autoimmune and neurodegenerative diseases.

Characterization and in vitro differentiation potency of early-passage canine amnion- and umbilical cord-derived mesenchymal stem cells as related to gestational age

Fetal adnexa are a non-controversial source of mesenchymal stem cells (MSCs) that have high plasticity, a high proliferation rate, and the ability to differentiate towards multiple lineages. MSC populations have been characterized for their stemness and differentiation capabilities; more recent work has focused on MSC selection and on establishing predictable elements to discriminate the cells with the most potential for regenerative medicine. In this study, we cytogenetically and molecularly characterized and followed the in vitro proliferation and differentiation potential of early-passage canine amniotic membrane MSCs (AM-MSCs) and umbilical cord matrix MSCs (UCM-MSCs) isolated from fetuses at early (35-40 days) and late (45-55 days) gestational ages. We found that cells from both fetal gestational ages showed similar features. In all examined cell lines, the morphology of proliferating cells typically appeared fibroblast-like. Population doublings, passaged up to 10 times, increased significantly with passage number. In both cell types, cell viability and chromosomal number and structure were not affected by gestational age at early passages. Passage-3 AM- and UCM-MSCs from both gestational phases also expressed embryonic (POU5F1) and mesenchymal (CD29, CD44) stemness markers, whereas hematopoietic and histocompatibility markers were never found in any sample. Passage-3 cell populations of each cell type were also multipotential as they could differentiate into neurocytes and osteocytes, based on cell morphology, specific stains, and molecular analysis. These results indicated that MSCs retrieved from the UCM and AM in the early and late fetal phases of gestation could be used for canine regenerative medicine.

Unravelling the pluripotency paradox in fetal and placental mesenchymal stem cells: Oct-4 expression and the case of The Emperor's New Clothes

Mesenchymal stem cells (MSC) from fetal-placental tissues have translational advantages over their adult counterparts, and have variably been reported to express pluripotency markers. OCT-4 expression in fetal-placental MSC has been documented in some studies, paradoxically without tumourogenicity in vivo. It is possible that OCT-4 expression is insufficient to induce true "stemness", but this issue is important for the translational safety of fetal-derived MSC. To clarify this, we undertook a systematic literature review on OCT-4 in fetal or adnexal MSC to show that most studies report OCT-4 message or protein expression, but no study provides definitive evidence of true OCT-4A expression. Discrepant findings were attributable not to different culture conditions, tissue sources, or gestational ages but instead to techniques used. In assessing OCT-4 as a pluripotency marker, we highlight the challenges in detecting the correct OCT-4 isoform (OCT-4A) associated with pluripotency. Although specific detection of OCT-4A mRNA is achievable, it appears unlikely that any antibody can reliably distinguish between OCT-4A and the pseudogene OCT-4B. Finally, using five robust techniques we demonstrate that fetal derived-MSC do not express OCT-4A (or by default OCT-4B). Reports suggesting OCT-4 expression in fetal-derived MSC warrant reassessment, paying attention to gene and protein isoforms, pseudogenes, and antibody choice as well as primer design. Critical examination of the OCT-4 literature leads us to suggest that OCT-4 expression in fetal MSC may be a case of "The Emperor's New Clothes" with early reports of (false) positive expression amplified in subsequent studies without critical attention to emerging refinements in knowledge and methodology.

Equine mesenchymal stem cells inhibit T cell proliferation through different mechanisms depending on tissue source

Mesenchymal stem cells (MSCs) are used in both human clinical trials and veterinary medicine for the treatment of inflammatory and immune-mediated diseases. MSCs modulate inflammation by decreasing the cells and products of the inflammatory response. Stimulated equine MSCs from bone marrow (BM), adipose tissue (AT), cord blood (CB), and umbilical cord tissue (CT) inhibit lymphocyte proliferation and decrease inflammatory cytokine production. We hypothesized that equine MSCs inhibit T cell proliferation through secreted mediators and that MSCs from different tissue sources decrease T cell proliferation through different mechanisms. To test our hypotheses, we inhibited interleukin-6 (IL-6), nitric oxide (NO), and prostaglandin E2 (PGE2) to determine their impact on stimulated T cell proliferation. We also determined how equine MSCs modulate lymphocyte proliferation either via cell cycle arrest or apoptosis. Inhibition of IL-6 or NO did not reverse the immunomodulatory effect of MSCs on activated T cells. In contrast, inhibition of PGE2 restored T cell proliferation, restored the secretion of tumor necrosis factor-α and interferon-γ, and increased IL-10 levels. MSCs from solid-tissue-derived sources, AT and CT, inhibited T cell proliferation through induction of lymphocyte apoptosis while blood-derived MSCs, BM and CB, induced lymphocyte cell cycle arrest. Equine MSCs from different tissue sources modulated immune cell function by both overlapping and unique mechanisms. MSC tissue source may determine immunomodulatory properties of MSCs and may have very practical implications for MSC selection in the application of MSC therapy.

Equine mesenchymal stem cells from bone marrow, adipose tissue and umbilical cord: immunophenotypic characterization and differentiation potential

Introduction

Studies with mesenchymal stem cells (MSCs) are increasing due to their immunomodulatory, anti-inflammatory and tissue regenerative properties. However, there is still no agreement about the best source of equine MSCs for a bank for allogeneic therapy. The aim of this study was to evaluate the cell culture and immunophenotypic characteristics and differentiation potential of equine MSCs from bone marrow (BM-MSCs), adipose tissue (AT-MSCs) and umbilical cord (UC-MSCs) under identical in vitro conditions, to compare these sources for research or an allogeneic therapy cell bank.

Methods

The BM-MSCs, AT-MSCs and UC-MSCs were cultured and evaluated in vitro for their osteogenic, adipogenic and chondrogenic differentiation potential. Additionally, MSCs were assessed for CD105, CD44, CD34, CD90 and MHC-II markers by flow cytometry, and MHC-II was also assessed by immunocytochemistry. To interpret the flow cytometry results, statistical analysis was performed using ANOVA.

Results

The harvesting and culturing procedures of BM-MSCs, AT-MSCs and UC-MSCs were feasible, with an average cell growth until the third passage of 25 days for BM-MSCs, 15 days for AT-MSCs and 26 days for UC-MSCs. MSCs from all sources were able to differentiate into osteogenic (after 10 days for BM-MSCs and AT-MSCs and 15 days for UC-MSCs), adipogenic (after 8 days for BM-MSCs and AT-MSCs and 15 days for UC-MSCs) and chondrogenic (after 21 days for BM-MSCs, AT-MSCs and UC-MSCs) lineages. MSCs showed high expression of CD105, CD44 and CD90 and low or negative expression of CD34 and MHC-II. The MHC-II was not detected by immunocytochemistry techniques in any of the MSCs studied.

Conclusions

The BM, AT and UC are feasible sources for harvesting equine MSCs, and their immunophenotypic and multipotency characteristics attained minimal criteria for defining MSCs. Due to the low expression of MHC-II by MSCs, all of the sources could be used in clinical trials involving allogeneic therapy in horses. However, the BM-MSCs and AT-MSCs showed fastest ‘‘in vitro’’ differentiation and AT-MSCs showed highest cell growth until third passage. These findings suggest that BM and AT may be preferable for cell banking purposes.

Human umbilical cord mesenchymal stem cells transplantation promotes cutaneous wound healing of severe burned rats

BACKGROUND

Severe burns are a common and highly lethal trauma. The key step for severe burn therapy is to promote the wound healing as early as possible, and reports indicate that mesenchymal stem cell (MSC) therapy contributes to facilitate wound healing. In this study, we investigated effect of human umbilical cord MSCs (hUC-MSCs) could on wound healing in a rat model of severe burn and its potential mechanism.

METHODS

Adult male Wistar rats were randomly divided into sham, burn, and burn transplanted hUC-MSCs. GFP labeled hUC-MSCs or PBS was intravenous injected into respective groups. The rate of wound closure was evaluated by Image Pro Plus. GFP-labeled hUC-MSCs were tracked by in vivo bioluminescence imaging (BLI), and human-specific DNA expression in wounds was detected by PCR. Inflammatory cells, neutrophils, macrophages, capillaries and collagen types I/III in wounds were evaluated by histochemical staining. Wound blood flow was evaluated by laser Doppler blood flow meter. The levels of proinflammatory and anti-inflammatory factors, VEGF, collagen types I/III in wounds were analyzed using an ELISA.

RESULTS

We found that wound healing was significantly accelerated in the hUC-MSC therapy group. The hUC-MSCs migrated into wound and remarkably decreased the quantity of infiltrated inflammatory cells and levels of IL-1, IL-6, TNF-α and increased levels of IL-10 and TSG-6 in wounds. Additionally, the neovascularization and levels of VEGF in wounds in the hUC-MSC therapy group were markedly higher than those in other control groups. The ratio of collagen types I and III in the hUC-MSC therapy group were markedly higher than that in the burn group at indicated time after transplantation.

CONCLUSION

The study suggests that hUC-MSCs transplantation can effectively improve wound healing in severe burned rat model. Moreover, these data might provide the theoretical foundation for the further clinical application of hUC-MSC in burn areas.

Gene therapy of ovarian cancer using IL-21-secreting human umbilical cord mesenchymal stem cells in nude mice

Background

The human umbilical cord mesenchymal stem cells (hUCMSCs) have the ability to migrate into tumors and therefore have been considered as an alternative source of mesenchymal progenitors for the therapy of malignant diseases. The present study was aimed to investigate effect of hUCMSCs as vehicles for a constant source of transgenic interleukin-21 (IL-21) on ovarian cancer in vivo.

Methods

The hUCMSCs were engineered to express IL-21 via lentiviral vector- designated ‘hUCMSCs-LV-IL-21’, and then were transplanted into SKOV3 ovarian cancer xenograft-bearing nude mice. The therapeutic efficacy and mechanisms of this procedure on ovarian cancer was evaluated.

Results

The isolated hUCMSCs were induced to differentiate efficiently into osteoblast and adipocyte lineages in vitro. The expressed IL-21 in the supernatant from hUCMSCs-LV-IL-21 obviously stimulated splenocyte’s proliferation. The hUCMSCs-LV-IL-21 significantly reduced SKOV3 ovarian cancer burden in mice indicated by tumor sizes compared with control mice. The expressed IL-21 not only regulated the levels of IFN-γ and TNF-α in the mouse serum but also increased the expression of NKG2D and MIC A molecules in the tumor tissues. The down regulation of β-catenin and cyclin-D1 in the tumor tissues may refer to the inhibition of SKOV3 ovarian cancer growth in mice. In addition, hUCMSCs did not form gross or histological teratomas up to 60 days posttransplantation in murine lung, liver, stomach and spleen.

Conclusion

These results clearly indicate a safety and usability of hUCMSCs-LV- IL-21 in ovarian cancer gene therapy, suggesting the strategy may be a promising new method for clinical treatment of ovarian cancer.

Biocompatibility of nano-hydroxyapatite/Mg-Zn-Ca alloy composite scaffolds to human umbilical cord mesenchymal stem cells from Wharton's jelly in vitro

Seeding cells and scaffolds play pivotal roles in bone tissue engineering and regenerative medicine. Wharton's jelly-derived mesenchymal stem cells (WJCs) from human umbilical cord represent attractive and promising seeding cells in tissue regeneration and engineering for treatment applications. This study was carried out to explore the biocompatibility of scaffolds to seeding cells in vitro. Rod-like nano-hydroxyapatite (RN-HA) and flake-like micro-hydroxyapatite (FM-HA) coatings were prepared on Mg-Zn-Ca alloy substrates using micro-arc oxidation and electrochemical deposition. WJCs were utilized to investigate the cellular biocompatibility of Mg-Zn-Ca alloys after different surface modifications by observing the cell adhesion, morphology, proliferation, and osteoblastic differentiation. The in vitro results indicated that the RN-HA coating group was more suitable for cell proliferation and cell osteoblastic differentiation than the FM-HA group, demonstrating better biocompatibility. Our results suggested that the RN-HA coating on Mg-Zn-Ca alloy substrates might be of great potential in bone tissue engineering.

Immunosuppressive properties of mesenchymal stromal cells derived from amnion, placenta, Wharton's jelly and umbilical cord

BACKGROUND

The role of bone marrow-derived mesenchymal stromal cells (BM-MSC) in preventing the incidence and ameliorating the severity of graft-versus-host disease (GvHD) has recently been reported. However, as the collection of BM-MSC is an invasive procedure, more accessible sources of MSC are desirable.

AIM

This study aimed to explore the alternative sources of MSC from amnion, placenta, Wharton's jelly and umbilical cord, which are usually discarded.

METHODS

MSC from those tissues were isolated using mechanical dissociation and enzymatic digestion. Their capacity for proliferation and differentiation, and ability to suppress alloreactive T-lymphocytes were studied and compared with those of BM-MSC.

RESULTS

MSC derived from amnion, placenta, Wharton's jelly and umbilical cord were similar to BM-MSC regarding the cell morphology, the immunophenotype as well as the differentiation ability. These MSC also elicited a similar degree of immunosuppression, as evidenced by the inhibition of alloreactive T-lymphocytes in the mixed lymphocyte reaction, compared with that of BM-MSC. MSC from umbilical cord and Wharton's jelly had a higher proliferative capacity, whereas those from amnion and placenta had a lower proliferative capacity compared with BM-MSC.

CONCLUSION

The results obtained from this study suggest that MSC from amnion, placenta, Wharton's jelly and umbilical cord can therefore be potentially used for substituting BM-MSC in several therapeutic applications, including the treatment of GvHD.