Characterization of mesenchymal stromal cells derived from full-term umbilical cord blood

Mesenchymal Stem Cell Therapy for Huntington Disease: A Meta-Analysis

Objective

Mesenchymal stem cell (MSC) therapy has been explored in Huntington disease (HD) as a potential therapeutic approach; however, a complete synthesis of these results is lacking. We conducted a meta-analysis to evaluate the effects of MSCs on HD.

Method

Eligible studies published before November 2022 were screened from Embase, PubMed, Web of Science, Medline, and Cochrane in accordance with PRISMA guidelines. ClinicalTrial.gov and the World Health Organization International Clinical Trials Registry Platform were also searched for registered clinical trials. The outcomes in rodent studies evaluated included morphological changes (striatal volume and ventricular volume), motor function (rotarod test, wire hang test, grip strength test, limb-clasping test, apomorphine-induced rotation test, and neuromuscular electromyography activity), cognition (Morris water maze test), and body weight.

Result

The initial search returned 362 records, of which 15 studies incorporating 346 HD rodents were eligible for meta-analysis. Larger striatal and smaller ventricular volumes were observed in MSC-treated animals compared to controls. MSCs transplanted before the occurrence of motor dysfunction rescued the motor incoordination of HD. Among different MSC sources, bone marrow mesenchymal stem cells were the most investigated cells and were effective in improving motor coordination. MSC therapy improved muscle strength, neuromuscular electromyography activity, cortex-related motor function, and striatum-related motor function, while cognition was not changed. The body weight of male HD rodents increased after MSC transplantation, while that of females was not affected.

Conclusion

Meta-analysis showed a positive effect of MSCs on HD rodents overall, as reflected in morphological changes, motor coordination, muscle strength, neuromuscular electromyography activity, cortex-related motor function, and striatum-related motor function, while cognition was not changed by MSC therapy.

Culture, Expansion and Differentiation of Mouse Bone-Derived Mesenchymal Stromal Cells

Mesenchymal stem/stromal cells (MSCs) are multipotent adult cells that are present in several tissues including the bone marrow (BM), in which they can differentiate in a variety of cell types such as osteoblasts, chondrocytes and adipocytes. The isolation of MSCs has been carried out by many studies that aim to control their differentiation into cartilaginous and bone cells in vitro in order to use this technology in the repair of damaged tissues. Here we describe the minimum requirements and an efficient method for isolation, expansion of mouse bone-derived multipotent mesenchymal stromal cells and their differentiation into osteoblasts, responsible for the bone matrix synthesis and mineralization.

Cross talk between mesenchymal and glioblastoma stem cells: Communication beyond controversies

Mesenchymal stem cells (MSCs) can be isolated from bone marrow or other adult tissues (adipose tissue, dental pulp, amniotic fluid, and umbilical cord). In vitro, MSCs grow as adherent cells, display fibroblast-like morphology, and self-renew, undergoing specific mesodermal differentiation. High heterogeneity of MSCs from different origin, and differences in preparation techniques, make difficult to uniform their functional properties for therapeutic purposes. Immunomodulatory, migratory, and differentiation ability, fueled clinical MSC application in regenerative medicine, whereas beneficial effects are currently mainly ascribed to their secretome and extracellular vesicles. MSC translational potential in cancer therapy exploits putative anti-tumor activity and inherent tropism toward tumor sites to deliver cytotoxic drugs. However, controversial results emerged evaluating either the therapeutic potential or homing efficiency of MSCs, as both antitumor and protumor effects were reported. Glioblastoma (GBM) is the most malignant brain tumor and its development and aggressive nature is sustained by cancer stem cells (CSCs) and the identification of effective therapeutic is required. MSC dualistic action, tumor-promoting or tumor-targeting, is dependent on secreted factors and extracellular vesicles driving a complex cross talk between MSCs and GBM CSCs. Tumor-tropic ability of MSCs, besides providing an alternative therapeutic approach, could represent a tool to understand the biology of GBM CSCs and related paracrine mechanisms, underpinning MSC-GBM interactions. In this review, recent findings on the complex nature of MSCs will be highlighted, focusing on their elusive impact on GBM progression and aggressiveness by direct cell-cell interaction and via secretome, also facing the perspectives and challenges in treatment strategies.

A simple, efficient and economical method for isolating and culturing human umbilical cord blood‑derived mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) hold broad therapeutic potential in various diseases, however, it is difficult to produce sufficient numbers of MSCs for clinical application, therefore, improved culture systems are required. The present study aimed to develop a novel method for isolating and culturing human umbilical cord blood‑derived mesenchymal stromal cells (hUCB‑MSCs). A sequential culture method was developed that uses two types of culture media to optimize the isolation and culture of hUCB‑MSCs. First, DMEM supplemented with mesenchymal stem cell growth supplement was used to improve the colony formation and primary culture success rates of hUCB‑MSCs. Then, after removing the heterogeneous cell population, ordinary DMEM was used from the fourth passage. This method obtained hUCB‑MSCs with high culture efficiency and at a greatly reduced cost. The optimal culture conditions were determined and the hUCB‑MSCs were phenotypically characterized after passaging. Taken together, this simple, efficient and economical method can produce a large number of high‑quality hUCB‑MSCs in <1 month, therefore facilitating the future clinical applications of hUCB‑MSCs.

Preterm umbilical cord blood derived mesenchymal stem/stromal cells protect preterm white matter brain development against hypoxia-ischemia

INTRODUCTION

Preterm infants are at high risk for white matter injury and subsequent neurodevelopmental impairments. Mesenchymal stem/stromal cells (MSC) have anti-inflammatory/immunomodulatory actions and are of interest for neural repair in adults and newborns. This study examined the neuroprotective effects of allogeneic MSC, derived from preterm umbilical cord blood (UCB), in a preterm sheep model of white matter injury.

METHODS

Quad-lineage differentiation, clonogenicity and self-renewal ability of UCB-derived MSC were confirmed. Chronically instrumented fetal sheep (0.7 gestation) received either 25 min hypoxia-ischemia (HI) to induce preterm brain injury, or sham-HI. Ten million MSC, or saline, were administered iv to fetuses at 12 h after HI. Fetal brains were collected 10d after HI for histopathology and immunocytochemistry.

RESULTS

HI induced white matter injury, as indicated by a reduction in CNPase-positive myelin fiber density. HI also induced microglial activation (Iba-1) in the periventricular white matter and internal capsule (P < .05 vs control). MSC administration following HI preserved myelination (P < .05), modified microglial activation, and promoted macrophage migration (CD163) and cell proliferation (Ki-67) within cerebral white matter (P < .05). Cerebral CXCL10 concentration was increased following MSC administration (P < .05), which was likely associated with macrophage migration and cell proliferation within the preterm brain. Additionally, MSC administration reduced systemic pro-inflammatory cytokine TNFα at 3d post-HI (P < .05).

CONCLUSIONS

UCB-derived MSC therapy preserved white matter brain structure following preterm HI, mediated by a suppression of microglial activation, promotion of macrophage migration and acceleration of self-repair within the preterm brain. UCB-derived MSC are neuroprotective, acting via peripheral and cerebral anti-inflammatory and immunomodulatory mechanisms.

Current Status of Canine Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Veterinary Medicine

Stem cell therapy has prompted the expansion of veterinary medicine both experimentally and clinically, with the potential to contribute to contemporary treatment strategies for various diseases and conditions for which limited or no therapeutic options are presently available. Although the application of various types of stem cells, such as bone marrow-derived mesenchymal stem cells (BM-MSCs), adipose tissue-derived mesenchymal stem cells (AT-MSCs), and umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), has promising potential to improve the health of different species, it is crucial that the benefits and drawbacks are completely evaluated before use. Umbilical cord blood (UCB) is a rich source of stem cells; nonetheless, isolation of mesenchymal stem cells (MSCs) from UCB presents technical challenges. Although MSCs have been isolated from UCB of diverse species such as human, equine, sheep, goat, and canine, there are inherent limitations of using UCB from these species for the expansion of MSCs. In this review, we investigated canine UCB (cUCB) and compared it with UCB from other species by reviewing recent articles published from February 2003 to June 2017 to gain an understanding of the limitations of cUCB in the acquisition of MSCs and to determine other suitable sources for the isolation of MSCs from canine. Our review indicates that cUCB is not an ideal source of MSCs because of insufficient volume and ethical issues. However, canine reproductive organs discarded during neutering may help broaden our understanding of effective isolation of MSCs. We recommend exploring canine reproductive and adipose tissue rather than UCB to fulfill the current need in veterinary medicine for the well-designed and ethically approved source of MSCs.

External magnetic field promotes homing of magnetized stem cells following subcutaneous injection

Background

Mesenchymal stem cells (MSCs) are multipotent stromal cells that have the ability to self-renew and migrate to sites of pathology. In vivo tracking of MSCs provides insights into both, the underlying mechanisms of MSC transformation and their potential as gene delivery vehicles. The aim of our study was to assess the ability of superparamagnetic iron oxide nanoparticles (SPIONs)-labeled Wharton’s Jelly of the human umbilical cord-derived MSCs (WJ-MSCs) to carry the green fluorescent protein (GFP) gene to cutaneous injury sites in a murine model.

Methods

WJ-MSCs were isolated from a fresh umbilical cord and were genetically transformed to carry the GFP gene using lentiviral vectors with magnetically labeled SPIONs. The SPIONs/GFP-positive WJ-MSCs expressed multipotent cell markers and demonstrated the potential for osteogenic and adipogenic differentiation. Fifteen skin-injured mice were divided into three groups. Group I was treated with WJ-MSCs, group II with SPIONs/GFP-positive WJ-MSCs, and group III with SPIONs/GFP-positive WJ-MSCs exposed to an external magnetic field (EMF). Magnetic resonance imaging and optical molecular imaging were performed, and images were acquired 1, 2, and 7 days after cell injection.

Results

The results showed that GFP could be intensively detected around the wound in vivo 24 h after the cells were injected. Furthermore, we observed an accumulation of WJ-MSCs at the wound site, and EMF exposure increased the speed of cell transport. In conclusion, our study demonstrated that SPIONs/GFP function as cellular probes for monitoring in vivo migration and homing of WJ-MSCs. Moreover, exposure to an EMF can increase the transportation efficiency of SPIONs-labeled WJ-MSCs in vivo.

Conclusions

Our findings could lead to the development of a gene carrier system for the treatment of diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12860-017-0140-1) contains supplementary material, which is available to authorized users.

The effects of culture conditions on the functionality of efficiently obtained mesenchymal stromal cells from human cord blood

BACKGROUND AIMS

Cord blood (CB) is an attractive source of mesenchymal stromal cells (MSCs) because of its abundant availability and ease of collection. However, the success rate of generating CB-MSCs is low. In this study, our aim was to demonstrate the efficiency of our previously described method to obtain MSCs from CB and further characterize them and to study the effects of different culture conditions on MSCs.

METHODS

CB-MSC cultures were established in low oxygen (3%) conditions on fibronectin in 10% fetal bovine serum containing culture medium supplemented with combinations of growth factors. Cells were characterized for their adipogenic, osteogenic and chondrogenic differentiation capacity; phenotype; and HOX gene expression profile. The functionality of the cells cultured in different media was tested in vitro with angiogenesis and T-cell proliferation assays.

RESULTS

We demonstrate 87% efficacy in generating MSCs from CB. The established cells had typical MSC characteristics with reduced adipogenic differentiation potential and a unique HOX gene fingerprint. Growth factor-rich medium and a 3% oxygen condition enhanced cell proliferation; however, the growth factor-rich medium had a negative effect on the expression of CD90. Dexamethasone-containing medium improved the capacity of the cells to suppress T-cell proliferation, whereas the cells grown without dexamethasone were more able to support angiogenesis.

CONCLUSIONS

Our results demonstrate that the composition of expansion medium is critical for the functionality of MSCs and should always be appropriately defined for each purpose.

Quality and exploitation of umbilical cord blood for cell therapy: Are we beyond our capabilities?

There is increasing interest in identifying novel stem cell sources for application in emerging cell therapies. In this context, umbilical cord blood (UCB) shows great promise in multiple clinical settings. The number of UCB banks has therefore increased worldwide, with the objective of preserving potentially life-saving cells that are usually discarded after birth. After a rather long and costly processing procedure, the resultant UCB-derived cell products are cryopreserved until transplantation to patients. However, in many cases, only a small proportion of administered cells engraft successfully. Thus, can we do any better regarding current UCB-based therapeutic approaches? Here we discuss concerns about the use of UCB that are not critically pondered by researchers, clinicians, and banking services, including wasting samples with small volumes and the need for more reliable quality and functional controls to ensure the biological activity of stem cells and subsequent engraftment and treatment efficacy. Finally, we appeal for collaborative agreements between research institutions and UCB banks in order to redirect currently discarded small-volume UCB units for basic and clinical research purposes. Developmental Dynamics 245:710-717, 2016. © 2016 Wiley Periodicals, Inc.

Vascular stem cells-potential for clinical application

INTRODUCTION

Cell therapy is a growing area of research as an alternative to pharmaceuticals or surgery for the treatment of ischaemic disease. Studies are focusing on delivering tissue-derived cells into damaged organs to promote vascular regeneration or gain of function.

SOURCES OF DATA

Pubmed, clinicaltrials.gov, BHF website.

AREAS OF AGREEMENT

Stem cells have the potential to become a viable treatment for many diseases, as indicated by the numerous pre-clinical studies demonstrating therapeutic benefit.

AREAS OF CONTROVERSY

The mechanisms of action for transplanted stem cells are still open to debate. Proposed mechanism includes direct cell incorporation and paracrine action. Additionally, the secretome produced by transplanted cells remains largely unknown.

GROWING POINTS

Initial studies focused on delivering stem cells by injection; however, current research is utilizing biomaterials to target cell delivery to specific areas.

AREAS TIMELY FOR DEVELOPING RESEARCH

Whilst stem cell research in the laboratory is expanding rapidly, transition into clinical studies is hindered by the availability of equivalent clinical grade reagents.

Isolation of human umbilical cord blood-derived osteoprogenitor cells: a promising candidate for cell-based therapy for bone repair

OBJECTIVE

The aim of this study was to evaluate the osteogenic potential of human umbilical cord blood-derived osteoprogenitor cells and to prove its applicability as a promising candidate for cell-based therapeutics for bone repair.

METHODS

Primary cultures of human umbilical blood cord adherent cells were expanded in vitro until passage 2 and seeded for osteodifferentiation study. Morphological (light microscopy), cytochemical (Von Kossa's method), and functional analyses (calcium level, alkaline phosphatase activity, and total protein content in cell culture) were carried out 7, 14, 21, and 28 days after the osteoinduction protocol.

RESULTS

The proliferative step showed colony-forming units in 7 days. After osteoinduction, cuboidal cellular morphology similar to osteoblasts at 14 days and mineralization nodules and biochemical changes (increased alkaline phosphatase level and calcium deposits) at 21 days confirmed the osteodifferentiation process.

CONCLUSION

Cell culture of human umbilical blood cord is a reliable technique, constituting itself as an alternative source of osteoprogenitor cells for experimental needs. More animal tests and clinical trials must be carried out to validate its use and to establish quality control of future autologous or allogeneic cell-based therapy aimed at bone repair.

Potency of umbilical cord blood- and Wharton's jelly-derived mesenchymal stem cells for scarless wound healing

Postnatally, scars occur as a consequence of cutaneous wound healing. Scarless wound healing is highly desired for patients who have undergone surgery or trauma, especially to exposed areas. Based on the properties of mesenchymal stem cells (MSCs) for tissue repair and immunomodulation, we investigated the potential of MSCs for scarless wound healing. MSCs were expanded from umbilical cord blood (UCB-MSCs) and Wharton’s jelly (WJ-MSCs) from healthy donors who underwent elective full-term pregnancy caesarean sections. UCB-MSCs expressed lower levels of the pre-inflammatory cytokines IL1A and IL1B, but higher levels of the extracellular matrix (ECM)-degradation enzymes MMP1 and PLAU compared with WJ-MSCs, suggesting that UCB-MSCs were more likely to favor scarless wound healing. However, we failed to find significant benefits for stem cell therapy in improving wound healing and reducing collagen deposition following the direct injection of 1.0 × 10⁵ UCB-MSCs and WJ-MSCs into 5 mm full-thickness skin defect sites in nude mice. Interestingly, the implantation of UCB-MSCs tended to increase the expression of MMP2 and PLAU, two proteases involved in degradation of the extracellular matrix in the wound tissues. Based on our data, UCB-MSCs are more likely to be a favorable potential stem cell source for scarless wound healing, although a better experimental model is required for confirmation.

Mesenchymal stromal cells derived from various tissues: Biological, clinical and cryopreservation aspects

Originally isolated from bone marrow, mesenchymal stromal cells (MSCs) have since been obtained from various fetal and post-natal tissues and are the focus of an increasing number of clinical trials. Because of their tremendous potential for cellular therapy, regenerative medicine and tissue engineering, it is desirable to cryopreserve and bank MSCs to increase their access and availability. A remarkable amount of research and resources have been expended towards optimizing the protocols, freezing media composition, cooling devices and storage containers, as well as developing good manufacturing practices in order to ensure that MSCs retain their therapeutic characteristics following cryopreservation and that they are safe for clinical use. Here, we first present an overview of the identification of MSCs, their tissue sources and the properties that render them suitable as a cellular therapeutic. Next, we discuss the responses of cells during freezing and focus on the traditional and novel approaches used to cryopreserve MSCs. We conclude that viable MSCs from diverse tissues can be recovered after cryopreservation using a variety of freezing protocols, cryoprotectants, storage periods and temperatures. However, alterations in certain functions of MSCs following cryopreservation warrant future investigations on the recovery of cells post-thaw followed by expansion of functional cells in order to achieve their full therapeutic potential.

Impact of umbilical cord blood-derived mesenchymal stem cells on cardiovascular research

Over the years, cell therapy has become an exciting opportunity to treat human diseases. Early enthusiasm using adult stem cell sources has been tempered in light of preliminary benefits in patients. Considerable efforts have been dedicated, therefore, to explore alternative cells such as those extracted from umbilical cord blood (UCB). In line, UCB banking has become a popular possibility to preserve potentially life-saving cells that are usually discarded after birth, and the number of UCB banks has grown worldwide. Thus, a brief overview on the categories of UCB banks as well as the properties, challenges, and impact of UCB-derived mesenchymal stem cells (MSCs) on the area of cardiovascular research is presented. Taken together, the experience recounted here shows that UCBMSCs are envisioned as attractive therapeutic candidates against human disorders arising and/or progressing with vascular deficit.

Could cord blood cell therapy reduce preterm brain injury?

Major advances in neonatal care have led to significant improvements in survival rates for preterm infants, but this occurs at a cost, with a strong causal link between preterm birth and neurological deficits, including cerebral palsy (CP). Indeed, in high-income countries, up to 50% of children with CP were born preterm. The pathways that link preterm birth and brain injury are complex and multifactorial, but it is clear that preterm birth is strongly associated with damage to the white matter of the developing brain. Nearly 90% of preterm infants who later develop spastic CP have evidence of periventricular white matter injury. There are currently no treatments targeted at protecting the immature preterm brain. Umbilical cord blood (UCB) contains a diverse mix of stem and progenitor cells, and is a particularly promising source of cells for clinical applications, due to ethical and practical advantages over other potential therapeutic cell types. Recent studies have documented the potential benefits of UCB cells in reducing brain injury, particularly in rodent models of term neonatal hypoxia–ischemia. These studies indicate that UCB cells act via anti-inflammatory and immuno-modulatory effects, and release neurotrophic growth factors to support the damaged and surrounding brain tissue. The etiology of brain injury in preterm-born infants is less well understood than in term infants, but likely results from episodes of hypoperfusion, hypoxia–ischemia, and/or inflammation over a developmental period of white matter vulnerability. This review will explore current knowledge about the neuroprotective actions of UCB cells and their potential to ameliorate preterm brain injury through neonatal cell administration. We will also discuss the characteristics of UCB-derived from preterm and term infants for use in clinical applications.

Comparative analysis of multilineage properties of mesenchymal stromal cells derived from fetal sources shows an advantage of mesenchymal stromal cells isolated from cord blood in chondrogenic differentiation potential

Background aims

Cord blood (CB) and amniotic fluid (AF) could represent new and attractive mesenchymal stromal cell (MSC) sources, but their potential therapeutic applications are still limited by lack of standardized protocols for isolation and differentiation. In particular, chondrogenic differentiation has never been deeply investigated.

Methods

MSCs were obtained from CB and AF samples collected during cesarean sections at term and compared for their biological and differentiation properties, with particular interest in cartilage differentiation, in which quantitative real-time polymerase chain reaction and immunohistochemical analyses were performed to evaluate the expression of type 2 collagen, type 10 collagen, SRY-box9 and aggrecan.

Results

We were able to isolate MSCs from 12 of 30 (40%) and 5 of 20 (25%) CB and AF units, respectively. Fluorescence in situ hybridization analysis indicated the fetal origin of isolated MSC strains. Both populations expressed mesenchymal but not endothelial and hematopoietic markers, even though we observed a lower expression of human leukocyte antigen (HLA) I in CB-MSCs. No differences in proliferation rate and cell cycle analysis could be detected. After osteogenic induction, both populations showed matrix mineralization and typical marker expression. Under chondrogenic conditions, pellets derived from CB-MSCs, in contrast with AF-MSCs pellets, were significantly larger, showed cartilage-like morphology and resulted positive for chondrocyte-associated markers, such as type 2 collagen, type 10 collagen, SRY-box9 and aggrecan.

Conclusions

Our results show that CB-MSCs and AF-MSCs collected at term differ from each other in their biological and differentiation properties. In particular, only CB-MSCs showed a clear chondrogenic potential and thus could represent an ideal candidate for cartilage-tissue engineering.

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.

Migration, proliferation, and differentiation of cord blood mesenchymal stromal cells treated with histone deacetylase inhibitor valproic Acid

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.

Transplantation of umbilical cord-derived mesenchymal stem cells into the striata of R6/2 mice: behavioral and neuropathological analysis

Introduction

Huntington’s disease (HD) is an autosomal dominant disorder caused by an expanded CAG repeat on the short arm of chromosome 4 resulting in cognitive decline, motor dysfunction, and death, typically occurring 15 to 20 years after the onset of motor symptoms. Neuropathologically, HD is characterized by a specific loss of medium spiny neurons in the caudate and the putamen, as well as subsequent neuronal loss in the cerebral cortex. The transgenic R6/2 mouse model of HD carries the N-terminal fragment of the human HD gene (145 to 155 repeats) and rapidly develops some of the behavioral characteristics that are analogous to the human form of the disease. Mesenchymal stem cells (MSCs) have shown the ability to slow the onset of behavioral and neuropathological deficits following intrastriatal transplantation in rodent models of HD. Use of MSCs derived from umbilical cord (UC) offers an attractive strategy for transplantation as these cells are isolated from a noncontroversial and inexhaustible source and can be harvested at a low cost. Because UC MSCs represent an intermediate link between adult and embryonic tissue, they may hold more pluripotent properties than adult stem cells derived from other sources.

Methods

Mesenchymal stem cells, isolated from the UC of day 15 gestation pups, were transplanted intrastriatally into 5-week-old R6/2 mice at either a low-passage (3 to 8) or high-passage (40 to 50). Mice were tested behaviorally for 6 weeks using the rotarod task, the Morris water maze, and the limb-clasping response. Following behavioral testing, tissue sections were analyzed for UC MSC survival, the immune response to the transplanted cells, and neuropathological changes.

Results

Following transplantation of UC MSCs, R6/2 mice did not display a reduction in motor deficits but there appeared to be transient sparing in a spatial memory task when compared to untreated R6/2 mice. However, R6/2 mice receiving either low- or high-passage UC MSCs displayed significantly less neuropathological deficits, relative to untreated R6/2 mice.

Conclusions

The results from this study demonstrate that UC MSCs hold promise for reducing the neuropathological deficits observed in the R6/2 rodent model of HD.

A comparative analysis of the adipogenic potential in human mesenchymal stromal cells from cord blood and other sources

BACKGROUND AIMS

Mesenchymal stromal cells (MSCs) from umbilical cord blood (CB) attract attention by significantly impaired or absent adipogenic differentiation compared with MSCs derived from bone marrow (BM) and adipose tissue (AT). The diverging adipogenic propensity between the developmentally younger CB-MSCs and MSCs of the adult AT and BM resembles the age-dependent process in the BM, where adipose tissue increases with advancing age, accompanied by loss of bone stability. Thus, MSCs appeal as an attractive model to study the adipogenic process with respect to tissue sources and developmental ages.

METHODS

We followed the expression of main adipogenic transcription factors, genes and protein markers in CB-, BM- and AT-MSCs under adipogenic induction, after silencing of preadipocyte factor 1 (Pref-1, PREF1) and after incubation with CB-plasma supplemented adipogenic media.

RESULTS

An inverse relation in the expression of adipogenesis-associated markers and PREF1 in CB-MSCs suggested an inhibitory role of Pref-1 toward adipogenesis. However, Pref-1 protein was rarely detected in CB-MSCs, and siRNA silencing of Pref-1 failed to induce adipogenic differentiation in CB-MSCs. Thus, the impaired adipogenic differentiation of CB-MSCs in vitro was unrelated to endogenous Pref-1 protein expression. Nevertheless CB-plasma containing Pref-1 protein revealed an anti-adipogenic effect on AT-MSCs.

CONCLUSIONS

Because Pref-1 is vastly abundant in CB-plasma and confers anti-adipogenic properties, Pref-1 in association with the ontogenic milieu probably induces long-lasting unresponsiveness toward adipogenic stimuli in CB-MSCs.

Third party cord blood transplant boosts autologous hematopoiesis in a case of persistent bone marrow aplasia after double transplant failure for B-thalassemia major

A 9-year-old female received an allogeneic stem cell transplant (SCT) from an ABO-incompatible HLA-matched sibling for β-thalassemia major, without achieving a complete donor chimerism. Subsequently, the patient received five donor lymphocyte infusions, without increasing donor chimerism, and autologous SCT. Due to the persistent bone marrow aplasia, the patient received a second allogeneic SCT from the same donor without obtaining any engrafment. After the double transplant failure, we performed an unrelated transplant from a full-matched umbilical cord blood (UCBT) without administering any neither conditioning regimen nor GVHD prophylaxis. Forty days after UCBT, trilinear engraftment was documented. Surprisingly, the hematopoietic reconstitution was related to the re-expansion of the autologous (beta-thalassemic) hematopoietic stem cell, as documented by chimerism studies. At present, 30 months after UCBT, there is stable hematopoietic autologous reconstitution. This is the first description of the restoration of autologous hematopoiesis obtained with UCBT in a thalassemia-major patient after a double transplant failure.

Comparative Evaluation of Human Mesenchymal Stem Cells of Fetal (Wharton's Jelly) and Adult (Adipose Tissue) Origin during Prolonged In Vitro Expansion: Considerations for Cytotherapy

Mesenchymal stem cells (MSCs) are somatic cells with a dual capacity for self-renewal and differentiation, and diverse therapeutic applicability, both experimentally and in the clinic. These cells can be isolated from various human tissues that may differ anatomically or developmentally with relative ease. Heterogeneity due to biological origin or in vitro manipulation is, nevertheless, considerable and may equate to differences in qualitative and quantitative characteristics which can prove crucial for successful therapeutic use. With this in mind, in the present study we have evaluated the proliferation kinetics and phenotypic characteristics of MSCs derived from two abundant sources, that is, fetal umbilical cord matrix (Wharton's jelly) and adult adipose tissue (termed WJSC and ADSC, resp.) during prolonged in vitro expansion, a process necessary for obtaining cell numbers sufficient for clinical application. Our results show that WJSC are derived with relatively high efficiency and bear a substantially increased proliferation capacity whilst largely sustaining the expression of typical immunophenotypic markers, whereas ADSC exhibit a reduced proliferation potential showing typical signs of senescence at an early stage. By combining kinetic with phenotypic data we identify culture thresholds up to which both cell types maintain their stem properties, and we discuss the practical implications of their differences.

Parameters that influence the isolation of multipotent mesenchymal stromal cells from human umbilical cord blood

BACKGROUND AND OBJECTIVES

Umbilical cord blood is an important source of stem cells. However, isolating multipotent mesenchymal stromal cells (MSCs) from umbilical cord blood presents methodological challenges. We compared the effectiveness of six approaches to improve the success rate of MSC isolation and proliferation from umbilical cord blood.

METHODS

Thirty umbilical cord blood units underwent investigation. In 10 samples, MNCs from each sample were divided into four groups to test the effect of negative immunodepletion (NI) alone (group A); NI plus basic fibroblastic growth factor (bFGF) supplementation together (group B); bFGF supplementation alone (group C); and culture with neither NI nor bFGF (group D). The cells of each group were isolated from 10mL of umbilical cord blood. For investigating the effect of sample volume (group E) and MesenCult Proliferation Kits (group F), cells were isolated from 45±2ml. MSCs were identified on the basis of morphological, flow cytometric and differentiation potential characteristics.

RESULTS

In groups of A-D, one week after the initial seeding, the cells showed a rounded appearance, and in the fourth week, many of them died. MSCs outgrowth was seen in 40% of the samples from group F, and this yield was further enhanced to 60% in cultures done with the MesenCult Proliferation Kit (group F). The fibroblast-like cells expanded rapidly and showed features of MSCs.

CONCLUSION

Sample volume was the parameter that showed the greatest influence on the isolation yield of MSCs from umbilical cord blood. This could be further enhanced by adding the MesenCult Proliferation Kit.

Umbilical cord blood for cardiovascular cell therapy: from promise to fact

Endothelial recovery and cell replacement are therapeutic challenges for cardiovascular medicine. Initially employed in the treatment of blood malignancies due to its high concentration of hematological precursors, umbilical cord blood (UCB) is now a non-controversial and accepted source of both hematopoietic and non-hematopoietic progenitors for a variety of emerging cell therapies in clinical trials. Here, we review the current therapeutic potential of UCB, focusing in recent evidence demonstrating the ability of UCB-derived mesenchymal stem cells to differentiate into the endothelial lineage and to develop new vasculature in vivo.

Transplantation of umbilical cord-derived mesenchymal stem cells as a novel strategy to protect the central nervous system: technical aspects, preclinical studies, and clinical perspectives

The prevention of perinatal neurological disabilities remains a major challenge for public health, and no neuroprotective treatment to date has proven clinically useful in reducing the lesions leading to these disabilities. Efforts are, therefore, urgently needed to test other neuroprotective strategies including cell therapies. Although stem cells have raised great hopes as an inexhaustible source of therapeutic products that could be used for neuroprotection and neuroregeneration in disorders affecting the brain and spinal cord, certain sources of stem cells are associated with potential ethical issues. The human umbilical cord (hUC) is a rich source of stem and progenitor cells including mesenchymal stem cells (MSCs) derived either from the cord or from cord blood. hUC MSCs (hUC-MSCs) have several advantages as compared to other types and sources of stem cells. In this review, we will summarize the most recent findings regarding the technical aspects and the preclinical investigation of these promising cells in neuroprotection and neuroregeneration, and their potential use in the developing human brain. However, extensive studies are needed to optimize the administration protocol, safety parameters, and potential preinjection cell manipulations before designing a controlled trial in human neonates.

Chondrogenesis from umbilical cord blood cells stimulated with BMP-2 and BMP-6

Umbilical cord blood contains undifferentiated mesenchymal stem cells (MSCs) with chondrogenic potential that may be used for the repair of joint damage. The role of growth factors during the process of chondrogenesis is still not entirely understood. The objective of this study was to evaluate the formation of chondrocytes, cartilaginous matrix and type II collagen from human umbilical cord blood stem cells exposed to two different growth factors, BMP-6 and BMP-2, while being cultured as a micromass or a monolayer. Umbilical cord blood was obtained from full-term deliveries, and then, mononuclear cells were separated and cultured for expansion. Afterward, these cells were evaluated by flow cytometry using antibodies specific for MSCs and induced to chondrogenic differentiation in micromass and monolayer cultures supplemented with BMP-2 and BMP-6. Cellular phenotype was evaluated after 7, 14 and 21 days by RT-PCR and Western blot analysis to identify the type II collagen and aggrecan. The expanded cells displayed surface antigens characteristic of mesenchymal progenitor cells and were negative for hematopoietic differentiation antigens. Type II collagen and aggrecan mRNAs were expressed from day 14 in cells stimulated with BMP-2 or BMP-6. Type II collagen was demonstrated by Western blotting in both groups, and the greatest expression was observed 21 days after the cells were stimulated with BMP-2 cultured in micromass. BMP-2 in micromass culture was more efficient to induce the chondrogenesis.

Mesenchymal stem cells isolated from human uterine cervix cancer tissues

In the present study, MSCs (mesenchymal stem cells) were successfully isolated and identified from hUCC (human uterine cervix cancer) tissues. The morphological appearance, immunophenotype, growth curve, cell cycle, cytogenetic features and differentiation potential of these cells were investigated. Results showed that cells isolated from the uterine cervix cancer tissues displayed fibroblast-like morphology and grew into colonies. Immunophenotyping by flow cytometry revealed that the isolated cells were positive for CD13, CD29, CD44, CD105 and HLA-I, while negative for CD10, CD14, CD31, CD34, CD38 and HLA-DR. The cells kept a normal karyotype by chromosome analysis. At the third passage, the percentages of cells in G0-/G1-, 2-/M- and S-phase were 84.94, 8.36 and 6.71%, respectively. Under appropriate induction conditions, these cells can differentiate into osteogenic, adipogenic cells and hepatocytes. Taken together, MSCs were confirmed to exist in hUCC tissues, which may provide a new target for clinical cancer therapy.

DLK-1 as a marker to distinguish unrestricted somatic stem cells and mesenchymal stromal cells in cord blood

In addition to hematopoietic stem cells, cord blood (CB) also contains different nonhematopoietic CD45-, CD34- adherent cell populations: cord blood mesenchymal stromal cells (CB MSC) that behave almost like MSC from bone marrow (BM MSC) and unrestricted somatic stem cells (USSC) that differentiate into cells of all 3 germ layers. Distinguishing between these populations is difficult due to overlapping features such as the immunophenotype or the osteogenic and chondrogenic differentiation pathway. Functional differences in the differentiation potential suggest different developmental stages or different cell populations. Here we demonstrate that the expression of genes and the differentiation toward the adipogenic lineage can discriminate between these 2 populations. USSC, including clonal-derived cells lacking adipogenic differentiation, strongly expressed &#x03B4;-like 1/preadipocyte factor 1 (DLK-1/PREF1) correlating with high proliferative potential, while CB MSC were characterized by a strong differentiation toward adipocytes correlating with a weak or negative DLK-1/PREF1 expression. Constitutive overexpression of DLK-1/PREF1 in CB MSC resulted in a reduced adipogenic differentiation, whereas silencing of DLK-1 in USSC resulted in adipogenic differentiation.

Umbilical cord-derived mesenchymal stromal cells modulate monocyte function to suppress T cell proliferation

Mesenchymal stromal cells (MSCs) may be derived from a variety of tissues, with human umbilical cord (UC) providing an abundant and noninvasive source. Human UC-MSCs share similar in vitro immunosuppressive properties as MSCs obtained from bone marrow and cord blood. However, the mechanisms and cellular interactions used by MSCs to control immune responses remain to be fully elucidated. In this paper, we report that suppression of mitogen-induced T cell proliferation by human UC-, bone marrow-, and cord blood-MSCs required monocytes. Removal of monocytes but not B cells from human adult PBMCs (PBMNCs) reduced the immunosuppressive effects of MSCs on T cell proliferation. There was rapid modulation of a number of cell surface molecules on monocytes when PBMCs or alloantigen-activated PBMNCs were cultured with UC-MSCs. Indomethacin treatment significantly inhibited the ability of UC-MSCs to suppress T cell proliferation, indicating an important role for PGE(2). Monocytes purified from UC-MSC coculture had significantly reduced accessory cell and allostimulatory function when tested in subsequent T cell proliferation assays, an effect mediated in part by UC-MSC PGE(2) production and enhanced by PBMNC alloactivation. Therefore, we identify monocytes as an essential intermediary through which UC-MSCs mediate their suppressive effects on T cell proliferation.

Multilineage differentiation potential of fibroblast-like stromal cells derived from human skin

Adult stem cells that reside in adult tissues have been deemed to possess great potential for clinical application because of their capabilities of self-renewal and differentiation. However, the limitations such as infection risks and low isolation rate make the search for appropriate source to be continued. Here, we demonstrate isolation of progenitors from human foreskin tissue samples, which have fibroblast-like morphology and could be easily propagated for more than 50 passages. These foreskin-derived fibroblast-like stromal cells (FDSCs) expressed CD90, CD105, CD166, CD73, SH3, and SH4, which is similar to the immunophenotypes of human bone marrow-derived mesenchymal stem cells. In comparison with Hs68, the human fibroblast cell line, FDSCs are positive for CD105 and absent for CD54 expression. Further, FDSCs could be induced to differentiate into osteocytes, adipocytes, neural cells, smooth muscle cells, Schwann-like cells, and hepatocyte-like cells. Interestingly, when cultured in Dulbecco's modified Eagle's medium/F12 medium, FDSCs can form spheres with increased expression levels of fibronectin and vimentin. In conclusion, foreskin can serve as a valuable source of multipotent cells with the capabilities for endodermal, mesodermal, and ectodermal cells. Coupled with the advantages of their easy access, isolation, and propagation, these foreskin-derived stromal cells might be of potential use in future studies in stem cell differentiation and therapeutic application.

Life-sparing effect of human cord blood-mesenchymal stem cells in experimental acute kidney injury

In search for new sources of mesenchymal stem cells (MSCs) for renal repair in acute kidney injury (AKI), we investigated the potential of human cord blood (CB)-MSCs to cure mice with AKI. Infusion of CB-MSCs in immunodeficient mice with cisplatin-induced AKI ameliorated both renal function and tubular cell injury, and prolonged survival. Transplanted CB-MSCs localized in peritubular areas, limited capillary alterations and neutrophil infiltration. Apoptosis reduced and tubular cell proliferation increased by virtue of stem cell capacity to produce growth factors. The reno-protective effect of CB-MSCs was further confirmed by their ability to inhibit oxidative damage and to induce the prosurvival factor Akt in tubular cells. The evidence that CB-MSCs in vitro increased the production of growth factors and inhibited IL-1 beta and TNFalpha synthesis when cocultured with damaged proximal tubular cells indicates a regenerative and anti-inflammatory action of stem cell treatment. Altogether these results highlight the potential of human CB-MSCs as future cell therapy for testing in human AKI.

Identification of variables that optimize isolation and culture of multipotent mesenchymal stem cells from equine umbilical-cord blood

OBJECTIVE-To optimize the isolation and culture of mesenchymal stem cells (MSCs) from umbilical-cord blood (UCB), identify variables that predicted successful MSC isolation, and determine whether shipping, processing, and cryopreservation altered MSC viability, recovery rates, and expansion kinetics. SAMPLE POPULATION-UCB samples from 79 Thoroughbred and Quarter Horse mares. PROCEDURES-UCB samples were processed to reduce volume and remove RBCs. Nucleated cells (NCs) were cryopreserved or grown in various culture conditions to optimize MSC monolayer expansion and proliferation. Donor and UCB-sample factors were analyzed to determine their influence on the success of MSC isolation and monolayer expansion. RESULTS-MSCs capable of multilineage in vitro differentiation were expanded from > 80% of UCB samples. Automated UCB processing and temperature-controlled shipping facilitated sterile and standardized RBC reduction and NC enrichment from UCB samples. The number of NCs after UCB samples were processed was the sole variable that predicted successful MSC expansion. The UCB-derived MSCs and NCs were successfully cryopreserved and thawed with no decrease in cell recovery, viability, or MSC proliferation. The use of fibronectin-coated culture plates and reduction of incubator oxygen tension from 20% to 5% improved the MSC isolation rate. Some UCB-derived MSC clones proliferated for > 20 passages before senescence. Onset of senescence was associated with specific immunocytochemical changes. CONCLUSIONS AND CLINICAL RELEVANCE-Equine UCB samples appeared to be a rich source of readily obtainable, highly proliferative MSCs that could be banked for therapeutic use.

Efficient expansion of mesenchymal stromal cells from umbilical cord under low serum conditions

BACKGROUND

Mesenchymal stromal cells (MSC) are of clinical interest for their potential use in regenerative medicine and immunotherapy. Originally derived from bone marrow (BM), MSC have now been isolated from most tissues, including umbilical cord (UC) and UC blood (UCB). If MSC from UC are biologically equivalent to those from BM, they would be attractive as a readily available and non-invasive source for cellular therapies.

METHODS

Sections of UC were separated into vascular and Wharton's jelly (WJ) fractions, which were then digested individually to release MSC that were isolated by plastic adherence in a 10% fetal calf serum (FCS) medium, or a low serum medium designed for multipotent adult progenitor cells (MAPC). The resulting perivascular (PV) and WJ MSC lines were assayed for expression of characteristic markers and differentiation and immunosuppressive properties.

RESULTS

MSC lines were readily derived from most UC tested. Cells grown in MAPC medium (MM) tended to be smaller and more elongated and expressed more nestin, but did not differ substantially in their growth rate, expression of other markers and differentiation capacity. All UC lines tested were adipogenic but poorly osteogenic, and were equivalent in their ability to suppress T-cell proliferation induced by phytohemagglutinin (PHA), activation beads and allostimulation.

CONCLUSIONS

UC is a convenient, efficient source of MSC that can be expanded under low serum conditions for application on future studies of tissue regeneration and immunosuppression.

A decreased positivity for CD90 on human mesenchymal stromal cells (MSCs) is associated with a loss of immunosuppressive activity by MSCs

Biologic and clinical interest in human mesenchymal stromal cells (hMSC) has risen over the last years, mainly due to their immunosuppressive properties. In this study, we investigated the basis of immunomodulant possible variability using hMSC from different sources (amniotic membrane, chorion, and bone marrow from either healthy subjects or patients with hematological malignancies, HM) and having discordant positivity for several immunological markers. The CD90+ hMSC reduced lymphoproliferative response in phytohemagglutinin (PHA) activated peripheral blood mononuclear cells (PBMC) via sHLA-G and IL-10 up-modulation. On the contrary, hMSC showing a significantly lower expression for CD90 antigen, elicited a lymphoproliferative allogeneic response in PHA/PBMCs without any increase in soluble HLA-G and IL-10 levels. These data seems to suggest that CD90 molecule may be considered a novel predictive marker for hMSC inhibitory ability, and might cooperate with HLA-G molecule in regulating suppressive versus stimulatory properties of hMSC. These results may have clinical implication in either transplantation or in regenerative medicine fields.

Human umbilical cord blood-derived mesenchymal stem cells do not differentiate into neural cell types or integrate into the retina after intravitreal grafting in neonatal rats

This study investigated the ability of mesenchymal stem cells (MSCs) derived from full-term human umbilical cord blood to survive, integrate and differentiate after intravitreal grafting to the degenerating neonatal rat retina following intracranial optic tract lesion. MSCs survived for 1 week in the absence of immunosuppression. When host animals were treated with cyclosporin A and dexamethasone to suppress inflammatory and immune responses, donor cells survived for at least 3 weeks, and were able to spread and cover the entire vitreal surface of the host retina. However, MSCs did not significantly integrate into or migrate through the retina. They also maintained their human antigenicity, and no indication of neural differentiation was observed in retinas where retinal ganglion cells either underwent severe degeneration or were lost. These results have provided the first in vivo evidence that MSCs derived from human umbilical cord blood can survive for a significant period of time when the host rat response is suppressed even for a short period. These results, together with the observation of a lack of neuronal differentiation and integration of MSCs after intravitreal grafting, has raised an important question as to the potential use of MSCs for neural repair through the replacement of lost neurons in the mammalian retina and central nervous system.

Umbilical cord blood mesenchymal stromal cells are neuroprotective and promote regeneration in a rat optic tract model

Exploitation of the ability of stem cells to protect damaged neuronal tissue may be a more viable strategy than cell replacement for repair of the central nervous system (CNS). In this study we assessed the capacity of human umbilical cord blood (hUCB)-derived mesenchymal stromal cells (MSCs) to protect and promote regeneration of axotomised neurons within the rat optic system. The optic tract of neonatal rats was transected at the level of the lateral geniculate nucleus, and MSCs were introduced into the lesion site. MSCs survived well up to 2 weeks after grafting, and did not migrate significantly or differentiate. In the presence of MSC grafts, host axonal processes were found to be present in the lesion site, and there was stimulation of an endogenous neural precursor population. Four weeks after grafting, retrograde tracer experiments demonstrated that grafted MSCs, as well as cells of a human fibroblast line, exerted a neuroprotective effect, rescuing a significant percentage of axotomised retinal ganglion cells (RGCs). Further experiments with retrograde and anterograde tracers strongly indicated that MSCs could also promote re-growth of axotomised RGCs to their target, the superior colliculus (SC). Further analysis showed that hUCB-derived MSCs secreted several immunomodulatory and neurotrophic factors in vitro, including TGFbeta1, CNTF, NT-3 and BDNF, which are likely to play a role in neuroprotection. Our data indicate that hUCB-derived MSCs may be an easily accessible, widely available source of cells that can contribute towards neural repair through rescue and regeneration of injured neurons.

Analysis of neural potential of human umbilical cord blood-derived multipotent mesenchymal stem cells in response to a range of neurogenic stimuli

We investigated the neurogenic potential of full-term human umbilical cord blood (hUCB)-derived multipotent mesenchymal stem cells (MSCs) in response to neural induction media or coculture with rat neural cells. Phenotypic and functional changes were assessed by immunocytochemistry, RT-PCR, and whole-cell patch-clamp recordings. Naive MSCs expressed both mesodermal and ectodermal markers prior to neural induction. Exposure to retinoic acid, basic fibroblast growth factor, or cyclic adenosine monophosphate (cAMP) did not stimulate neural morphology, whereas exposure to dibutyryl cAMP and 3-isobutyl-1-methylxanthine stimulated a neuron-like morphology but also appeared to be cytotoxic. All protocols stimulated increases in expression of the neural precursor marker nestin, but expression of mature neuronal or glial markers MAP2 and GFAP was not observed. Nestin expression increases were serum level dependent. Electrophysiological properties of MSCs were studied with whole-cell patch-clamp recordings. The MSCs possessed no ionic currents typical of neurons before or after neural induction protocols. Coculture of hUCB-derived MSCs and rat neural cells induced some MSCs to adopt an astrocyte-like morphology and express GFAP protein and mRNA. Our data suggest hUCB-derived MSCs do not transdifferentiate into mature functioning neurons in response to the above neurogenic protocols; however, coculture with rat neural cells led to a minority adopting an astrocyte-like phenotype.

5-Azacytidine-treated human mesenchymal stem/progenitor cells derived from umbilical cord, cord blood and bone marrow do not generate cardiomyocytes in vitro at high frequencies

BACKGROUND AND OBJECTIVES

Mesenchymal stem/progenitor cells (MSCs) are multipotent progenitors that differentiate into such lineages as bone, fat, cartilage and stromal cells that support haemopoiesis. Bone marrow MSCs can also contribute to cardiac repair, although the mechanism for this is unclear. Here, we examine the potential of MSCs from different sources to generate cardiomyocytes in vitro, as a means for predicting their therapeutic potential after myocardial infarction.

MATERIALS AND METHODS

Mesenchymal stem/progenitor cells were isolated from the perivascular tissue and Wharton's jelly of the umbilical cord and from cord blood. Their immunophenotype and differentiation potential to generate osteoblasts, chondrocytes, adipocytes and cardiomyoxcytes in vitro was compared with those of bone marrow MSCs.

RESULTS

Mesenchymal stem/progenitor cells isolated from umbilical cord and cord blood were phenotypically similar to bone marrow MSCs, the exception being in the expression of CD106, which was absent on umbilical cord MSCs, and CD146 that was highly expressed in cord blood MSCs. They have variable abilities to give rise to osteoblasts, chondrocytes and adipocytes, with bone marrow MSCs being the most robust. While a small proportion (approximately 0.07%) of bone marrow MSCs could generate cardiomyocyte-like cells in vitro, those from umbilical cord and cord blood did not express cardiac markers either spontaneously or after treatment with 5-azacytidine.

CONCLUSION

Although MSCs may be useful for such clinical applications as bone or cartilage repair, the results presented here indicate that such cells do not generate cardiomyocytes frequently enough for cardiac repair. Their efficacy in heart repair is likely to be due to paracrine mechanisms.