Neural cells derived from adult bone marrow and umbilical cord blood

Cell Therapy Strategies on Duchenne Muscular Dystrophy: A Systematic Review of Clinical Applications

Duchenne Muscular Dystrophy (DMD) is an inherited genetic disorder characterized by progressive degeneration of muscle tissue, leading to functional disability and premature death. Despite extensive research efforts, the discovery of a cure for DMD continues to be elusive, emphasizing the need to investigate novel treatment approaches. Cellular therapies have emerged as prospective approaches to address the underlying pathophysiology of DMD. This review provides an examination of the present situation regarding cell-based therapies, including CD133 + cells, muscle precursor cells, mesoangioblasts, bone marrow-derived mononuclear cells, mesenchymal stem cells, cardiosphere-derived cells, and dystrophin-expressing chimeric cells. A total of 12 studies were found eligible to be included as they were completed cell therapy clinical trials, clinical applications, or case reports with quantitative results. The evaluation encompassed an examination of limitations and potential advancements in this particular area of research, along with an assessment of the safety and effectiveness of cell-based therapies in the context of DMD. In general, the available data indicates that diverse cell therapy approaches may present a new, safe, and efficacious treatment modality for patients diagnosed with DMD. However, further studies are required to comprehensively understand the most advantageous treatment approach and therapeutic capacity.

Cdk5 activation promotes Cos-7 cells transition towards neuronal-like cells

Objectives

Cyclin-dependent kinase 5 (Cdk5) activity is specifically active in neurogenesis, and Cdk5 and neocortical neurons migration related biomarker are expressed in Cos-7 cells. However, the function of Cdk5 on the transformation of immortalized Cos-7 cells into neuronal-like cells is not clear.

Methods

Cdk5 kinase activity was measured by [γ-32P] ATP and p81 phosphocellulose pads based method. The expression of neuron liker markers was evaluated by immunofluorescence, real-time PCR, Western blot, and Elisa.

Results

P35 overexpression upregulated Cdk5 kinase activity in Cos-7 cells. p35 mediated Cdk5 expression promoted the generation of nerite-like outgrowth. Compared with the empty vector, p35-induced Cdk5 activation resulted in time-dependent increase in neuron-like marker, including Tau, NF-H, NF-H&M, and TuJ1. Tau-5 and NF-M exhibited increased expression at 48 h while TuJ1 was only detectable after 96 h in p35 expressed Cos-7 cells. Additionally, the neural cell biomarkers exhibited well colocation with p35 proteins. Next-generation RNA sequence showed that p35 overexpression significantly upregulated the level of nerve growth factor (NGF). Gene set enrichment analysis showed significant enrichment of multiple neuron development pathways and increased NGF expression after p35 overexpression.

Conclusion

p35-mediated Cdk5 activation promotes the transformation of immortalized Cos-7 cells into neuronal-like cells by upregulating NGF level.

Neuronal induction and bioenergetics characterization of human forearm adipose stem cells from Parkinson’s disease patients and healthy controls

Neurodegenerative diseases, such as Parkinson’s disease, are heterogeneous disorders with a multifactorial nature involving impaired bioenergetics. Stem-regenerative medicine and bioenergetics have been proposed as promising therapeutic targets in the neurologic field. The rationale of the present study was to assess the potential of human-derived adipose stem cells (hASCs) to transdifferentiate into neuronal-like cells (NhASCs and neurospheres) and explore the hASC bioenergetic profile. hASC neuronal transdifferentiation was performed through neurobasal media and differentiation factor exposure. High resolution respirometry was assessed. Increased MAP-2 neuronal marker protein expression upon neuronal induction (p<0.05 undifferentiated hASCs vs. 28–36 days of differentiation) and increased bIII-tubulin neuronal marker protein expression upon neuronal induction (p<0.05 undifferentiated hASCs vs. 6-28-36 days of differentiation) were found. The bioenergetic profile was detectable through high-resolution respirometry approaches in hASCs but did not lead to differential oxidative capacity rates in healthy or clinically diagnosed PD-hASCs. We confirmed the capability of transdifferentiation to the neuronal-like profile of hASCs derived from the forearms of human subjects and characterized the bioenergetic profile. Suboptimal maximal respiratory capacity trends in PD were found. Neuronal induction leading to positive neuronal protein expression markers is a relevant issue that encourages the suitability of NhASC models in neurodegeneration.

Capacitive electrical stimulation of a conducting polymeric thin film induces human mesenchymal stem cell osteogenesis

Electroactive materials based on conductive polymers are promising options for tissue engineering and regenerative medicine applications. In the present work, the conducting copolymers of poly (3,4-ethylenedioxythiophene) and poly (d, l-lactic acid) (PEDOT-co-PDLLA) with PEDOT:PDLLA molar ratios of 1:50, 1:25, and 1:5 were synthesized and compared to the insulating macromonomer of EDOT-PDLLA as an experimental control. Bone marrow-derived human mesenchymal stem cells (hMSC-BM) were cultured on the copolymers and the macromonomer thin films inside a bioreactor that induced a capacitive electrical stimulation (CES) with an electric field of 100 mV/mm for 2 h per day for 21 days. Under CES, the copolymers exhibited good cell viability and promoted the differentiation from hMSC-BM to osteogenic lineages, revealed by higher mineralization mainly when the contents of conducting segments of PEDOT (i.e., copolymer with 1:25 and 1:5 PEDOT:PDLLA ratios) were increased. The results indicate that the intrinsic electrical conductivity of the substrates is an important key point for the effectiveness of the electric field generated by the CES, intending to promote the differentiation effect for bone cells.

Clinical Practice of Umbilical Cord Blood Stem Cells in Transplantation and Regenerative Medicine - Prodigious Promise for Imminent Times

The umbilical cord blood is usually disposed of as an unwanted material after parturition; however, today, it is viewed as a regenerative medication so as to create the organ tissues. This cord blood gathered from the umbilical cord is made up of mesenchymal stem cells, hematopoietic stem cells, and multipotent non-hematopoietic stem cells having many therapeutic effects as these stem cells are utilized to treat malignancies, hematological ailments, inborn metabolic problem, and immune deficiencies. Presently, numerous clinical applications for human umbilical cord blood inferred stem cells, as stem cell treatment initiate new research. These cells are showing such a boon to stem cell treatment; it is nevertheless characteristic that the prospect of conservation of umbilical cord blood is gaining impetus. Current research works have demonstrated that about 80 diseases, including cancer, can be treated or relieved utilizing umbilical cord blood stem cells, and every year, many transplants have been effectively done around the world. However, in terms of factors, including patient selection, cell preparation, dosing, and delivery process, the treatment procedure for therapy with minimally manipulated stem cells can be patented. It is also worth thinking about how this patent could affect cord blood banks. Meanwhile, the utilization of cord blood cells is controversial and adult-derived cells may not be as successful, so numerous clinicians have begun working with stem cells that are acquired from umbilical cord blood. This review epitomizes a change in outlook from what has been completed with umbilical cord blood cell research and cord blood banking on the grounds that cord blood cells do not require much in the method of handling for cryopreservation or for transplantation in regenerative medicine.

Gene Profiles in the Early Stage of Neuronal Differentiation of Mouse Bone Marrow Stromal Cells Induced by Basic Fibroblast Growth Factor

A stably established population of mouse bone marrow stromal cells (BMSCs) with self-renewal and multilineage differentiation potential was expanded in vitro for more than 50 passages. These cells express high levels of mesenchymal stem cell markers and can be differentiated into adipogenic, chondrogenic, and osteogenic lineages in vitro. Subjected to basic fibroblast growth factor (bFGF) treatment, a typical neuronal phenotype was induced in these cells, as supported by neuronal morphology, induction of neuronal markers, and relevant electrophysiological excitability. To identify the genes regulating neuronal differentiation, cDNA microarray analysis was conducted using mRNAs isolated from cells differentiated for different time periods (0, 4, 24, and 72 h) after bFGF treatment. Various expression patterns of neuronal genes were stimulated by bFGF. These gene profiles were shown to be involved in developmental, functional, and structural integration of the nervous system. The expression of representative genes stimulated by bFGF in each group was verified by RT-PCR. Amongst proneural genes, the mammalian achate-schute homolog 1 (Mash-1), a basic helix-loop-helix transcriptional factor, was further demonstrated to be significantly upregulated. Overexpression of Mash-1 in mouse BMSCs was shown to induce the expression of neuronal specific enolase (NSE) and terminal neuronal morphology, suggesting that Mash-1 plays an important role in the induction of neuronal differentiation of mouse BMSCs.

New insights on the reparative cells in bone regeneration and repair

Bone possesses a remarkable repair capacity to regenerate completely without scar tissue formation. This unique characteristic, expressed during bone development, maintenance and injury (fracture) healing, is performed by the reparative cells including skeletal stem cells (SSCs) and their descendants. However, the identity and functional roles of SSCs remain controversial due to technological difficulties and the heterogeneity and plasticity of SSCs. Moreover, for many years, there has been a biased view that bone marrow is the main cell source for bone repair. Together, these limitations have greatly hampered our understanding of these important cell populations and their potential applications in the treatment of fractures and skeletal diseases. Here, we reanalyse and summarize current understanding of the reparative cells in bone regeneration and repair and outline recent progress in this area, with a particular emphasis on the temporal and spatial process of fracture healing, the sources of reparative cells, an updated definition of SSCs, and markers of skeletal stem/progenitor cells contributing to the repair of craniofacial and long bones, as well as the debate between SSCs and pericytes. Finally, we also discuss the existing problems, emerging novel technologies and future research directions in this field.

Differences in Mitochondrial Membrane Potential Identify Distinct Populations of Human Cardiac Mesenchymal Progenitor Cells

Adult human cardiac mesenchymal progenitor cells (hCmPC) are multipotent resident populations involved in cardiac homeostasis and heart repair. Even if the mechanisms have not yet been fully elucidated, the stem cell differentiation is guided by the mitochondrial metabolism; however, mitochondrial approaches to identify hCmPC with enhanced stemness and/or differentiation capability for cellular therapy are not established. Here we demonstrated that hCmPCs sorted for low and high mitochondrial membrane potential (using a lipophilic cationic dye tetramethylrhodamine methyl ester, TMRM), presented differences in energy metabolism from preferential glycolysis to oxidative rates. TMRM-high cells are highly efficient in terms of oxygen consumption rate, basal and maximal respiration, and spare respiratory capacity compared to TMRM-low cells. TMRM-high cells showed characteristics of pre-committed cells and were associated with higher in vitro differentiation capacity through endothelial, cardiac-like, and, to a lesser extent, adipogenic and chondro/osteogenic cell lineage, when compared with TMRM-low cells. Conversely, TMRM-low showed higher self-renewal potential. To conclude, we identified two hCmPC populations with different metabolic profile, stemness maturity, and differentiation potential. Our findings suggest that metabolic sorting can isolate cells with higher regenerative capacity and/or long-term survival. This metabolism-based strategy to select cells may be broadly applicable to therapies.

Role of cerebrospinal fluid in differentiation of human dental pulp stem cells into neuron-like cells

Human dental pulp stem cells (hDPSCs) could be differentiated into neuron like-cells under particular microenvironments. It has been reported that a wide range of factors, presented in cerebrospinal fluid (CSF), playing part in neuronal differentiation during embryonic stages, we herein introduce a novel culture media complex to differentiate hDPSCs into neuron-like cells. The hDPSCs were initially isolated and characterized. The CSF was prepared from the Cisterna magna of 19-day-old Wistar rat embryos, embryonic cerebrospinal fluid (E-CSF). The hDPSCs were treated by 5% E-CSF for 2 days, then neurospheres were cultured in DMEM/F12 supplemented with 10^-6 μm retinoic acid (RA), glial-derived neurotrophic factor and brain-derived neurotrophic factor for 6 days. The cells which were cultured in basic culture medium were considered as control group. Morphology of differentiated cells as well as process elongation were examined by an inverted microscope. In addition, the neural differentiation markers (Nestin and MAP2) were studied employing immunocytochemistry. Neuronal-like processes appeared 8 days after treatment. Neural progenitor marker (Nestin) and a mature neural marker (MAP2) were expressed in treated group. Moreover Nissl bodies were found in the cytoplasm of treated group. Taking these together, we have designed a simple protocol for generating neuron-like cells using CSF from the hDPSCs, applicable for cell therapy in several neurodegenerative disorders including Alzheimer's disease.

The Extracts of Human Fetal Brain Induce the Differentiation of Human Umbilical Cord Mesenchymal Stem Cells into Dopaminergic Neuron Containing Cells

Mesenchymal stem cells (MSCs) have the potential to differentiate into neuron-like cells, which may provide a new strategy for the clinical treatment of neurodegenerative diseases such as Parkinson's disease (PD). However, the application of MSCs in the patients is still limited as the reason of efficiency and safety of transplantation. The aim of this study is to develop a new method and induce human umbilical cord MSCs (hUCMSCs) into neuron-like cells. Results from flow cytometry indicate that the isolated MSCs from hUCMSCs exhibited a typical phenotype of adult stem cells and express CD44, CD54, CD73, CD90, CD105, CD166, and HLA-ABC. Furthermore, the induced cells from hUCMSCs could spontaneously express different neural cell markers [neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP)], even transcription factors related to dopaminergic neuron's development (Nurr1, Wnt-1, and En-1). Moreover, after treatment of EHFBT (extracts of human fetal brain tissue), hUCMSCs can express neuronal markers such as Nestin, LIM homeobox transcription factor 1 beta (LMX1B), dopamine beta hydroxylase (DBH), and dopamine transporter (DAT). In summary, a method that can induce hUCMSCs into dopaminergic neuron containing cells is established in vitro by the treatment of EHFBT. This would provide us a new cell source for PD in clinical treatment in the future.

Partial Improvement of Spatial Memory Damages by Bone Marrow Mesenchymal Stem Cells Transplantation Following Trimethyltin Chloride Administration in the Rat CA1

Introduction:

Trimethyltin Chloride (TMT) is a neurotoxin that can kill neurons in the nervous system and activate astrocytes. This neurotoxin mainly damages the hippocampal neurons. After TMT injection, behavioral changes such as aggression and hyperactivity have been reported in animals along with impaired spatial and learning memory. Hence, TMT is a suitable tool for an experimental model of neurodegeneration. The present study aims to determine the palliative effects of Bone Marrow-derived Mesenchymal Stem Cells (BM-MSCs) on the hippocampi of rats damaged from TMT exposure.

Methods:

We assigned 28 male Wistar rats to the following groups: control, model, vehicle, and treatment. The groups received Intraperitoneal (IP) injections of 8 mg/kg TMT. After one week, stem cells were stereotactically injected into the CA1 of the right rats’ hippocampi. Spatial memory was determined by the Morris Water Maze (MWM) test 6 weeks after cell transplantation. Finally, the rats’ brains were perfused and stained by cresyl violet to determine the numbers of cells in the Cornus Ammonis (CA1) section of the hippocampus. We assessed the expressions of Glial Fibrillary Acidic Protein (GFAP) and Neuronal-specific Nuclear (NeuN) proteins in the right hippocampus by Western blot.

Results:

The MWM test showed that the treatment group had significantly higher traveled distances in the target quarter compared with the model and vehicle groups (P<0.05). Based on the result of cell count (Nissl staining), the number of cells increased in the treatment group compared with the model and vehicle groups (P<0.05). Western blot results showed up-regulation of GFAP and NeuN proteins in the model, vehicle, and treatment groups compared with the control group.

Conclusion:

Injection of BM-MSCs may lead to a behavioral and histological improvement in TMT-induced neurotoxicity by increasing the number of pyramidal neurons and improving memory.

Nanoparticle technology and stem cell therapy team up against neurodegenerative disorders

The convergence of nanoparticles and stem cell therapy holds great promise for the study, diagnosis, and treatment of neurodegenerative disorders. Researchers aim to harness the power of nanoparticles to regulate cellular microenvironment, improve the efficiency of cell and drug delivery to the brain, and enhance the survival of stem cell transplants. Understanding the various properties of different nanoparticles is key to applying them to clinical therapies; the many distinct types of nanoparticles offer unique capacities for medical imaging, diagnosis, and treatment of neurodegeneration disorders. In this review we introduce the biology of Alzheimer's, Parkinson's Disease, and amyotrophic lateral sclerosis, and discuss the potentials and shortcomings of metal, silica, lipid-based, polymeric, and hydrogel nanoparticles for diagnosis and treatment of neurodegenerative disorders. We then provide an overview of current strategies in stem cell therapies and how they can be combined with nanotechnology to improve clinical outcomes.

Cell-based therapy against prion diseases

Despite multiple efforts to find treatments, prion diseases are still incurable. The currently available therapeutic strategies are mostly based on compounds to inhibit pathological PrP (PrPSc) accumulation, and cellular PrP (PrP^C) conversion into PrP^Sc. However, they cannot reverse the pathological changes already present in the brain. Cell-based therapeutic strategies could promote the repair of the pre-existing brain damage. The few available data come mostly from preclinical studies using neural stem cells, bone marrow-derived microglia and mesenchymal stem cells, as cell sources. Moreover, the benefits of cell-based therapeutic strategies could be linked not only to the replacement of damaged cells, but also to the secretion of trophic factors by the grafted cells that might modulate inflammation, cell death, or endogenous neurogenesis.

Bone Marrow Stromal Cells for Repair of the Spinal Cord: Towards Clinical Application

Stem cells have been recognized and intensively studied for their potential use in restorative approaches for degenerative diseases and traumatic injuries. In the central nervous system (CNS), stem cell-based strategies have been proposed to replace lost neurons in degenerative diseases such as Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis (Lou Gehrig's disease), or to replace lost oligodendrocytes in demyelinating diseases such as multiple sclerosis. Stem cells have also been implicated in repair of the adult spinal cord. An impact to the spinal cord results in immediate damage to tissue including blood vessels, causing loss of neurons, astrocytes, and oligodendrocytes. In time, more tissue nearby or away from the injury site is lost due to secondary injury. In case of relatively minor damage to the cord some return of function can be observed, but in most cases the neurological loss is permanent. This review will focus on in vitro and in vivo studies on the use of bone marrow stromal cells (BMSCs), a heterogeneous cell population that includes mesenchymal stem cells, for repair of the spinal cord in experimental injury models and their potential for human application. To optimally benefit from BMSCs for repair of the spinal cord it is imperative to develop in vitro techniques that will generate the desired cell type and/or a large enough number for in vivo transplantation approaches. We will also assess the potential and possible pitfalls for use of BMSCs in humans and ongoing clinical trials.

"Neuronal-Like Differentiation of Murine Mesenchymal Stem Cell Line: Stimulation by Juglans regia L. Oil"

Mesenchymal stem cells have been extensively used for cell-based therapies especially in neuronal diseases. Studies still continue to delineate mechanisms involved in differentiating mesenchymal stem cells into neuronal cells under experimental conditions as they have low mortality rate and hence, the number of cells available for experiments is much more limited. Culturing and differentiating of neuronal cell is more challenging as they do not undergo cell division thus, bringing them to differentiate proves to be a difficult task. Here, the aim of this study is to investigate whether Juglans regia L. (walnut oil) differentiates multipotent, C3H10T1/2 cells, a murine mesenchymal stem cell line, into neuronal cells. A simple treatment protocol induced C3H10T1/2 cells to exhibit a neuronal phenotype. With this optimal differentiation protocol, almost all cells exhibited neuronal morphology. The cell bodies extended long processes. C3H10T1/2 cells were plated and treated with walnut oil post 24 h of plating. The treatment was given (with walnut oil treated cultures with or without control cultures) at different concentrations. The cultured cells were then stained with cresyl violet acetate solution which was used to stain the Nissl substance in the cytoplasm of the induced neuronal culture. The results indicated that the C3H10T1/2 cells differentiated into neuronal-like cells with long outgrowths of axon-like structures able to take up the cresyl violet acetate stain indicating their preliminary differentiation into neuronal-like morphology with walnut oil treatment. Treating the mesenchymal stem cells can in future establish a cultured mesenchymal stem cell line as neuronal differentiating cell line model.

Stem cell therapies in age-related neurodegenerative diseases and stroke

Aging, a complex process associated with various structural, functional and metabolic changes in the brain, is an important risk factor for neurodegenerative diseases and stroke. These diseases share similar neuropathological changes, such as the formation of misfolded proteins, oxidative stress, loss of neurons and synapses, dysfunction of the neurovascular unit (NVU), reduction of self-repair capacity, and motor and/or cognitive deficiencies. In addition to gray matter dysfunction, the plasticity and repair capacity of white matter also decrease with aging and contribute to neurodegenerative diseases. Aging not only renders patients more susceptible to these disorders, but also attenuates their self-repair capabilities. In addition, low drug responsiveness and intolerable side effects are major challenges in the prevention and treatment of senile diseases. Thus, stem cell therapies-characterized by cellular plasticity and the ability to self-renew-may be a promising strategy for aging-related brain disorders. Here, we review the common pathophysiological changes, treatments, and the promises and limitations of stem cell therapies in age-related neurodegenerative diseases and stroke.

Systemic Administration of Allogeneic Mesenchymal Stem Cells Does Not Halt Osteoporotic Bone Loss in Ovariectomized Rats

Mesenchymal stem cells (MSCs) have innate ability to self-renew and immunosuppressive functions, and differentiate into various cell types. They have become a promising cell source for treating many diseases, particular for bone regeneration. Osteoporosis is a common metabolic bone disorder with elevated systemic inflammation which in turn triggers enhanced bone loss. We hypothesize that systemic infusion of MSCs may suppress the elevated inflammation in the osteoporotic subjects and slow down bone loss. The current project was to address the following two questions: (1) Will a single dose systemic administration of allogenic MSCs have any effect on osteoporotic bone loss? (2) Will multiple administration of allogenic MSCs from single or multiple donors have similar effect on osteoporotic bone loss? 18 ovariectomized (OVX) rats were assigned into 3 groups: the PBS control group, MSCs group 1 (receiving 2x106 GFP-MSCs at Day 10, 46, 91 from the same donor following OVX) and MSCs group 2 (receiving 2x106 GFP-MSCs from three different donors at Day 10, 46, 91). Examinations included Micro-CT, serum analysis, mechanical testing, immunofluorescence staining and bone histomorphometry analysis. Results showed that BV/TV at Day 90, 135, BMD of TV and trabecular number at Day 135 in the PBS group were significantly higher than those in the MSCs group 2, whereas trabecular spacing at Day 90, 135 was significantly smaller than that in MSCs group 2. Mechanical testing data didn't show significant difference among the three groups. In addition, the ELISA assay showed that level of Rantes in serum in MSCs group 2 was significantly higher than that of the PBS group, whereas IL-6 and IL-10 were significantly lower than those of the PBS group. Bone histomorphometry analysis showed that Oc.S/BS and Oc.N/BS in the PBS group were significant lower than those in MSCs group 2; Ob.S/BS and Ob.N/BS did not show significant difference among the three groups. The current study demonstrated that systemic administration of allogenic MSCs had no obvious effect on osteoporotic bone loss in OVX rats when using the cells from the same donor; and repeated injection of allogeneic MSCs from different donors might promote bone loss in OVX rats. These findings indicate that despite allogenic MSCs systemic infusion is safe, their administration alone may not be an effective mean for preventing osteoporotic bone loss.

Supplementation freeze-thawed media with selenium protect adipose-derived mesenchymal stem cells from freeze-thawed induced injury

Successful freezed-thaw of adipose-derived mesenchymal stem cells (ADMSCs) could be a major step in regenerative medicine as well as in the cloning of animal breeds. The aim of this study was to evaluate the efficacy of selenium on the optimizing of freezed-thaw media in the ADMSCs. ADMSCs were extracted from NMRI mice and purified with positive selection Monoclonal CD105 Antibody (PE) and negative selection Monoclonal CD31 and CD45 Antibody using MACS method as well as differentiation to adipose and bone tissue. ADMSCs were divided into four groups. ADMSCs were freezed-thaw under standard condition with or without the addition of 5 ng/ml selenium to both the cryopreservation and thawing solutions. Frozen cells were thawed after four months and viability and cytotoxicity of the cells were analyzed by the Trypan blue test and MTT assay respectively. RNA was extracted and cDNA was synthesized and the expression of apoptotic genes (P53, Fas, Bax, Caspase3, and Bcl2) was examined using Real time-PCR Rotor gene 2009. This study compares slow and rapid methods of cryopreservation. After thawing, viability of the cells treated with selenium was higher than the control group in rapid and slow cryopreserved ADMSCs. Also, the percentage of living cells in the slow cooling method was considerably more than with the rapid cooling method. After analysis of the results using Real time-PCR, the Bcl2 gene was shown to be expressed in both the rapid and slow cooling methods. In the rapid cooling group in addition to the BCL-2 gene, p53 was also expressed. It appears that selenium prevented the apoptotic genes from expression due to its anti-apoptotic effects. The slow cooling method is better and more optimized for ADMSCs protecting them from oxidative damage to a greater extent compared to the rapid cooling method.

Human pluripotent stem cell (PSC)-derived mesenchymal stem cells (MSCs) show potent neurogenic capacity which is enhanced with cytoskeletal rearrangement

Mesenchymal stem cells (MSCs) are paraxial mesodermal progenitors with potent immunomodulatory properties. Reports also indicate that MSCs can undergo neural-like differentiation, offering hope for use in neurodegenerative diseases. However, ex vivo expansion of these rare somatic stem cells for clinical use leads to cellular senescence. A newer source of MSCs derived from human pluripotent stem cells (PSC) can offer the 'best-of-both-worlds' scenario, abrogating the concern of teratoma formation while preserving PSC proliferative capacity. PSC-derived MSCs (PSC-MSCs) also represent MSCs at the earliest developmental stage, and we found that these MSCs harbor stronger neuro-differentiation capacity than post-natal MSCs. PSC-MSCs express higher levels of neural stem cell (NSC)-related genes and transcription factors than adult bone marrow MSCs at baseline, and rapidly differentiate into neural-like cells when cultured in either standard neurogenic differentiation medium (NDM) or when the cytoskeletal modulator RhoA kinase (ROCK) is inhibited. Interestingly, when NDM is combined with ROCK inhibition, PSC-MSCs undergo further commitment, acquiring characteristics of post-mitotic neurons including nuclear condensation, extensive dendritic growth, and neuron-restricted marker expression including NeuN, β-III-tubulin and Doublecortin. Our data demonstrates that PSC-MSCs have potent capacity to undergo neural differentiation and also implicate the important role of the cytoskeleton in neural lineage commitment.

Circulating phagocytes: the ancient and conserved interface between immune and neuroendocrine function

Immune and neuroendocrine functions display significant overlap in highly divergent and evolutionarily distant models such as molluscs, crustaceans, insects and mammals. Fundamental players in this crosstalk are professional phagocytes: macrophages in vertebrates and immunocytes in invertebrates. Although they have different developmental origins, macrophages and immunocytes possess comparable functions and differentiate under the control of evolutionarily conserved transcription factors. Macrophages and immunocytes share their pools of receptors, signalling molecules and pathways with neural cells and the neuro-endocrine system. In crustaceans, adult transdifferentiation of circulating haemocytes into neural cells has been documented recently. In light of developmental, molecular and functional evidence, we propose that the immune-neuroendocrine role of circulating phagocytes pre-dates the split of protostomian and deuterostomian superphyla and has been conserved during the evolution of the main groups of metazoans.

The fate of systemically administrated allogeneic mesenchymal stem cells in mouse femoral fracture healing

Introduction

The fate and whereabouts of the allogenic mesenchymal stem cells (MSCs) following their transplantation are not well understood. The present study investigated the fate of systemically administrated allogeneic MSCs in mouse fracture healing by using in vivo imaging and immunohistochemistry methods.

Methods

Open femoral fracture with internal fixation was established in 30 FVB mice, which were assigned to three groups receiving phosphate-buffered saline (PBS) injection, MSC systemic injection, or MSC local injection. Luc-MSCs (5 × 10⁵) isolated from the luciferase transgenic mice with FVB background were injected at 4 days after fracture. All animals were terminated at 5 weeks after fracture; examinations included bioluminescence-based in vivo imaging, micro-computer tomography, mechanical testing, histology, immunohistochemistry, and double immunofluorescence staining.

Results

The bioluminescence signals of the Luc-MSCs at the fracture site could be detected for 12–14 days following their injection in the Luc-MSC local injection group, whereas in the Luc-MSC systemic injection group, Luc-MSCs were initially trapped in lungs for about 8–9 days and then gradually redistributed to the fracture site. Bone mineral density, bone volume/tissue volume, ultimate load, and E-modulus in the MSC injection groups were significantly higher than those in the PBS group. Double immunostaining demonstrated that the MSC local injection group had more Luc-positive cells, and there was a higher apoptotic rate at the fracture site than the MSC systemic injection group. Both Luciferase-positive MSCs and osteoblasts were present in the callus in the MSC injection groups at 5 weeks after fracture, suggesting that some of allogenic Luc-MSCs contributed to the new bone formation. Only less than 3 % of injected Luc-MSCs remained at the fracture site in the MSC injection groups at 5 weeks following the fracture, and the rest of the injected Luc-MSCs disappeared.

Conclusions

Our data showed that both systemic and local injection of allogeneic MSCs promoted fracture healing through enhancing biomechanical properties, bone content, and enlarged callus sizes. Immunohistochemistry confirmed that the injected MSCs are still present in the fracture site and can differentiate into osteoblasts to participate in fracture healing even at 5 weeks following the fracture. These findings provide useful information for the use of allogenic MSCs for cell therapy applications.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0198-7) contains supplementary material, which is available to authorized users.

Bone Marrow Stromal Cells Combined with a Honeycomb Collagen Sponge Facilitate Neurite Elongation in Vitro and Neural Restoration in the Hemisected Rat Spinal Cord

In the last decade, researchers and clinicians have reported that transplantation of bone marrow stromal cells (BMSCs) promotes functional recovery after brain or spinal cord injury (SCI). However, an appropriate scaffold designed for the injured spinal cord is needed to enhance the survival of transplanted BMSCs and to promote nerve regeneration. We previously tested a honeycomb collagen sponge (HC), which when applied to the transected spinal cord allowed bridging of the gap with nerve fibers. In this study, we examined whether the HC implant combined with rat BMSCs increases nerve regeneration in vitro and enhances functional recovery in vivo. We first evaluated the neurite outgrowth of rat dorsal root ganglion (DRG) explants cultured on HC with or without BMSCs in vitro. Regeneration of neurites from the DRGs was increased by BMSCs combined with HC scaffolds. In the in vivo study, 3-mm-long HC scaffolds with or without BMSCs were implanted into the hemisected rat thoracic spinal cord. Four weeks after the procedure, rats implanted with HC scaffolds containing BMSCs displayed better motor and sensory recovery than those implanted with HC scaffolds only. Histologically, more CGRP-positive sensory fibers at the implanted site and 5-HT-positive serotonergic fibers contralateral to the implanted site were observed in spinal cords receiving BMSCs. Furthermore, more rubrospinal neurons projected distally to the HC implant containing BMSCs. Our study indicates that the application of BMSCs in a HC scaffold in the injured spinal cord directly promoted sensory nerve and rubrospinal tract regeneration, thus resulting in functional recovery.

Wharton's jelly derived mesenchymal stromal cells: Biological properties, induction of neuronal phenotype and current applications in neurodegeneration research

Multipotent mesenchymal stromal cells, also known as mesenchymal stem cells (MSC), can be isolated from bone marrow or other tissues, including fat, muscle and umbilical cord. It has been shown that MSC behave in vitro as stem cells: they self-renew and are able to differentiate into mature cells typical of several mesenchymal tissues. Moreover, the differentiation toward non-mesenchymal cell lineages (e.g. neurons) has been reported as well. The clinical relevance of these cells is mainly related to their ability to spontaneously migrate to the site of inflammation/damage, to their safety profile thanks to their low immunogenicity and to their immunomodulation capacities. To date, MSCs isolated from the post-natal bone marrow have represented the most extensively studied population of adult MSCs, in view of their possible use in various therapeutical applications. However, the bone marrow-derived MSCs exhibit a series of limitations, mainly related to their problematic isolation, culturing and use. In recent years, umbilical cord (UC) matrix (i.e. Wharton's jelly, WJ) stromal cells have therefore emerged as a more suitable alternative source of MSCs, thanks to their primitive nature and the easy isolation without relevant ethical concerns. This review seeks to provide an overview of the main biological properties of WJ-derived MSCs. Moreover, the potential application of these cells for the treatment of some known dysfunctions in the central and peripheral nervous system will also be discussed.

Systemic and Local Administration of Allogeneic Bone Marrow-Derived Mesenchymal Stem Cells Promotes Fracture Healing in Rats

Mesenchymal stem cells (MSCs) are immune privileged and a cell source for tissue repair. Previous studies showed that there is systemic mobilization of osteoblastic precursors to the fracture site. We hypothesized that both systemic and local administration of allogeneic MSCs may promote fracture healing. Bone marrow-derived MSCs and skin fibroblasts were isolated from GFP Sprague-Dawley rats, cultured, and characterized. Closed transverse femoral fracture with internal fixation was established in 48 adult male Sprague-Dawley rats, which were randomly assigned into four groups receiving PBS injection, MSC systemic injection, fibroblast systemic injection, and MSC fracture site injection; 2 × 10(6) cells were injected at 4 days after fracture. All animals were sacrificed at 5 weeks after fracture; examinations included weekly radiograph, micro-CT, mechanical testing, histology, immunohistochemistry, and double immunofluorescence. The callus size of MSC injection groups was significantly larger among all the groups. Radiographs and 3D reconstruction images showed that the fracture gaps united in the MSC injected groups, while gaps were still seen in the fibroblast and PBS injection groups. The mechanical properties were significantly higher in the MSC injection groups than those in the fibroblast and PBS groups, but no difference was found between the MSC local and systemic injection groups. Immunohistochemistry and double immunofluorescence demonstrated that GFP-positive MSCs were present in the callus in the MSC injection groups at 5 weeks after fracture, and some differentiated into osteoblasts. Quantitative analysis revealed the number of GFP-positive cells in the callus in the MSC systemic injection group was significantly lower than that of the MSC local injection group. The proportion of GFP osteoblasts in GFP-positive cells in the MSC systemic injection group was significantly lower than that of the MSC local injection group. These findings provide critical insight for developing MSC-based therapies, and systemic injection of allogeneic MSCs may be a novel treatment method for promoting fracture repair.

Differentiation of equine mesenchymal stromal cells into cells of neural lineage: potential for clinical applications

Mesenchymal stromal cells (MSCs) are able to differentiate into extramesodermal lineages, including neurons. Positive outcomes were obtained after transplantation of neurally induced MSCs in laboratory animals after nerve injury, but this is unknown in horses. Our objectives were to test the ability of equine MSCs to differentiate into cells of neural lineage in vitro, to assess differences in morphology and lineage-specific protein expression, and to investigate if horse age and cell passage number affected the ability to achieve differentiation. Bone marrow-derived MSCs were obtained from young and adult horses. Following demonstration of stemness, MSCs were neurally induced and microscopically assessed at different time points. Results showed that commercially available nitrogen-coated tissue culture plates supported proliferation and differentiation. Morphological changes were immediate and all the cells displayed a neural crest-like cell phenotype. Expression of neural progenitor proteins, was assessed via western blot or immunofluorescence. In our study, MSCs generated from young and middle-aged horses did not show differences in their ability to undergo differentiation. The effect of cell passage number, however, is inconsistent and further experiments are needed. Ongoing work is aimed at transdifferentiating these cells into Schwann cells for transplantation into a peripheral nerve injury model in horses.

Neural cell injury microenvironment induces neural differentiation of human umbilical cord mesenchymal stem cells

This study aimed to investigate the neural differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs) under the induction of injured neural cells. After in vitro isolation and culture, passage 5 hUCMSCs were used for experimentation. hUCMSCs were co-cultured with normal or Aβ_1-40-injured PC12 cells, PC12 cell supernatant or PC12 cell lysate in a Transwell co-culture system. Western blot analysis and flow cytometry results showed that choline acetyltransferase and microtubule-associated protein 2, a specific marker for neural cells, were expressed in hUCMSCs under various culture conditions, and highest expression was observed in the hUCMSCs co-cultured with injured PC12 cells. Choline acetyltransferase and microtubule-associated protein 2 were not expressed in hUCMSCs cultured alone (no treatment). Cell Counting Kit-8 assay results showed that hUCMSCs under co-culture conditions promoted the proliferation of injured PC12 cells. These findings suggest that the microenvironment during neural tissue injury can effectively induce neural cell differentiation of hUCMSCs. These differentiated hUCMSCs likely accelerate the repair of injured neural cells.

Umbilical cord-derived mesenchymal stem cells retain immunomodulatory and anti-oxidative activities after neural induction

The immunomodulatory and anti-oxidative activities of differentiated mesenchymal stem cells contribute to their therapeutic efficacy in cell-replacement therapy. Mesenchymal stem cells were isolated from human umbilical cord and induced to differentiate with basic fibroblast growth factor, nerve growth factor, epidermal growth factor, brain-derived neurotrophic factor and forskolin. The mesenchymal stem cells became rounded with long processes and expressed the neural markers, Tuj1, neurofilament 200, microtubule-associated protein-2 and neuron-specific enolase. Nestin expression was significantly reduced after neural induction. The expression of immunoregulatory and anti-oxidative genes was largely unchanged prior to and after neural induction in mesenchymal stem cells. There was no significant difference in the effects of control and induced mesenchymal stem cells on lymphocyte proliferation in co-culture experiments. However, the expression of human leukocyte antigen-G decreased significantly in induced neuron-like cells. These results suggest that growth factor-based methods enable the differentiation of mesenchymal stem cell toward immature neuronal-like cells, which retain their immunomodulatory and anti-oxidative activities.

Neural stem cells: ready for therapeutic applications?

Neural stem cells (NSCs) offer a unique and powerful tool for basic research and regenerative medicine. However, the challenges that scientists face in the comprehension of the biology and physiological function of these cells are still many. Deciphering NSCs fundamental biological aspects represents indeed a crucial step to control NSCs fate and functional integration following transplantation, and is essential for a safe and appropriate use of NSCs in injury/disease conditions. In this review, we focus on the biological properties of NSCs and discuss how these cells may be exploited to provide effective therapies for neurological disorders. We also review and discuss ongoing NSC-based clinical trials for these diseases.

Neural stem cells: ready for therapeutic applications?

Neural stem cells (NSCs) offer a unique and powerful tool for basic research and regenerative medicine. However, the challenges that scientists face in the comprehension of the biology and physiological function of these cells are still many. Deciphering NSCs fundamental biological aspects represents indeed a crucial step to control NSCs fate and functional integration following transplantation, and is essential for a safe and appropriate use of NSCs in injury/disease conditions. In this review, we focus on the biological properties of NSCs and discuss how these cells may be exploited to provide effective therapies for neurological disorders. We also review and discuss ongoing NSC-based clinical trials for these diseases.

Long live the stem cell: the use of stem cells isolated from post mortem tissues for translational strategies

The "stem cell" has become arguably one of the most important biological tools in the arsenal of translational research directed at regeneration and repair. It remains to be seen whether every tissue has its own stem cell niche, although relatively recently a large amount of research has focused on isolating and characterizing tissue-specific stem cell populations, as well as those that are able to be directed to transdifferentiate into a variety of different lineages. Traditionally, stem cells are isolated from the viable tissue of embryonic, fetal, or adult living hosts; from "fresh" donated tissues that have been surgically or otherwise removed (biopsies), or obtained directly from tissues within minutes to several hours post mortem (PM). These human progenitor/stem cell sources remain potentially highly controversial, since they are accompanied by various still-unresolved ethical, social, moral and legal challenges. Due to the limited number of "live" donors, the small amount of material obtained from biopsies and difficulties during purification processes, harvesting from cadaveric material presents itself as an alternative strategy that could provide a hitherto untapped source of stem cells. However, PM stem cells are not without their own unique set of limitations including difficulty of obtaining samples, limited supply of material, variations in delay between death and sample collection, possible lack of medication history and suboptimal retrospective assignment of diagnostic and demographic data. This article is part of a Directed Issue entitled: Regenerative Medicine: The challenge of translation.

Wnts enhance neurotrophin-induced neuronal differentiation in adult bone-marrow-derived mesenchymal stem cells via canonical and noncanonical signaling pathways

Wnts were previously shown to regulate the neurogenesis of neural stem or progenitor cells. Here, we explored the underlying molecular mechanisms through which Wnt signaling regulates neurotrophins (NTs) in the NT-induced neuronal differentiation of human mesenchymal stem cells (hMSCs). NTs can increase the expression of Wnt1 and Wnt7a in hMSCs. However, only Wnt7a enables the expression of synapsin-1, a synaptic marker in mature neurons, to be induced and triggers the formation of cholinergic and dopaminergic neurons. Human recombinant (hr)Wnt7a and general neuron makers were positively correlated in a dose- and time-dependent manner. In addition, the expression of synaptic markers and neurites was induced by Wnt7a and lithium, a glycogen synthase kinase-3β inhibitor, in the NT-induced hMSCs via the canonical/β-catenin pathway, but was inhibited by Wnt inhibitors and frizzled-5 (Frz5) blocking antibodies. In addition, hrWnt7a triggered the formation of cholinergic and dopaminergic neurons via the non-canonical/c-jun N-terminal kinase (JNK) pathway, and the formation of these neurons was inhibited by a JNK inhibitor and Frz9 blocking antibodies. In conclusion, hrWnt7a enhances the synthesis of synapse and facilitates neuronal differentiation in hMSCS through various Frz receptors. These mechanisms may be employed widely in the transdifferentiation of other adult stem cells.

An improved protocol for isolation and culture of mesenchymal stem cells from mouse bone marrow

Mesenchymal stem cells (MSCs) from bone marrow are main cell source for tissue repair and engineering, and vehicles of cell-based gene therapy. Unlike other species, mouse bone marrow derived MSCs (BM-MSCs) are difficult to harvest and grow due to the low MSCs yield. We report here a standardised, reliable, and easy-to-perform protocol for isolation and culture of mouse BM-MSCs. There are five main features of this protocol. (1) After flushing bone marrow out of the marrow cavity, we cultured the cells with fat mass without filtering and washing them. Our method is simply keeping the MSCs in their initial niche with minimal disturbance. (2) Our culture medium is not supplemented with any additional growth factor. (3) Our method does not need to separate cells using flow cytometry or immunomagnetic sorting techniques. (4) Our method has been carefully tested in several mouse strains and the results are reproducible. (5) We have optimised this protocol, and list detailed potential problems and trouble-shooting tricks. Using our protocol, the isolated mouse BM-MSCs were strongly positive for CD44 and CD90, negative CD45 and CD31, and exhibited tri-lineage differentiation potentials. Compared with the commonly used protocol, our protocol had higher success rate of establishing the mouse BM-MSCs in culture. Our protocol may be a simple, reliable, and alternative method for culturing MSCs from mouse bone marrow tissues.

Differentiation of neurosphere-derived rat neural stem cells into oligodendrocyte-like cells by repressing PDGF-α and Olig2 with triiodothyronine

One of the approaches for treating demyelination diseases is cytotherapy, and adult stem cells are potential sources. In this investigation, we tried to increase the yield of oligodendrocyte-like cells (OLCs) by inducing neural stem cells generated from BMSCs-derived neurospheres, which were used for deriving the neural stem cells (NSCs). The latter were induced into OLCs by heregulin, PDGF-AA, bFGF and triiodothyronine (T3). The BMSCs, NS, NSCs and OLCs were characterized by using immunocytochemistry for fibronectin, CD44, CD90, CD45, Oct-4, O4, Olig2, O1 and MBP markers. PDGF receptor α (PDGFR-α), Olig2 and MOG expression were evaluated by RT-PCR. The BMSCs expressed CD44, CD90, CD106 and Oct-4; the NSCs were immunoreactive to nestin and neurofilament 68. Incubation of the NSCs for 4 days with heregulin, PDGF-AA and bFGF resulted in their induction into oligodendrocyte progenitor-like cells (OPLCs), which immunoreacted to O4, Olig2 and O1, while Olig2 and PDGFR-α were detected by RT-PCR. Replacing heregulin, PDGF-AA and bFGF with T3 for 6 days resulted in repression of O4, O1, Olig2 and PDGFR-α. The OLCs were co-cultured with motoneurons resulted in induction of MOG and MBP, which were expressed in functional OLCs. The latter can be generated from BMSCs-derive NS with high yield.

Behaviour and ultrastructure of human bone marrow-derived mesenchymal stem cells immobilised in alginate-poly-l-lysine-alginate microcapsules

CONTEXT

Human bone marrow mesenchymal stem cells (hBM-MSCs) show a great promise for the treatment of a variety of diseases. Despite the previous trials to encapsulate hBM-MSCs in alginate-poly-l-lysine-alginate (APA) systems, the various changes that follow immobilisation have not been ascertained yet.

OBJECTIVE

Determine the various consequences derived from entrapment on cell behaviour, putting special emphasis on the ultrastructure.

METHODS

hBM-MSCs were immobilised in APA microcapsules to further characterise their viability, metabolic activity, proliferation, VEGF-secretability, and morphology.

RESULTS

The VEGF produced by monolayer hBM-MSCs increased significantly 1 d post-encapsulation, and was maintained for at least 4  weeks. TEM imaging of cells revealed well preserved ultrastructure indicating protein synthesis and high metabolic activity.

CONCLUSION

Although APA microencapsulation did not support 100% of fully viable hBM-MSCs for long-term cultures, it was conceived to enhance both VEGF secretion and metabolic activity while not losing their stemness characteristics.

Conditioned medium of human adipose-derived mesenchymal stem cells mediates protection in neurons following glutamate excitotoxicity by regulating energy metabolism and GAP-43 expression

Glutamate excitotoxicity has been implicated as one of the pathological mechanisms contributing to neuronal cell death and is involved in many neurological disorders. Stem cell transplantation is a promising approach for the treatment of nervous system damage or diseases. Previous studies have shown that mesenchymal stem cells (MSCs) have important therapeutic effects in experimental animal and preclinical disease model of central nervous system pathology. However, it is not well understood whether neurogenesis of MSCs or MSC conditioned-medium (CM) containing microparticles mediates therapeutic effects. Here, we investigated the neuroprotective effects of human adipose-derived MSCs (AMSCs) on cortical neurons using models of glutamate excitotoxicity. Following exposure to glutamate (100 μM, 15 min), cortical neurons were co-cultured with either AMSCs separated by a semiporous membrane (prohibiting direct cell-cell contact) or with AMSC-CM for 18 h. Compared to untreated control groups, AMSCs and AMSC-CM partially and similarly reduced neuronal cell damages, as indicated by reduced LDH release, a decreased number of trypan-positive cells and a decline in the number of apoptotic nuclei. Protection by CM was associated with increased GAP-43 expression and an elevated number of GAP-43-positive neurites. Furthermore, CM increased levels of ATP, NAD(+) and NADH and the ratio of NAD(+)/NADH, while preventing a glutamate-induced decline in mitochondrial membrane potential. These results demonstrate that AMSC-CM mediates direct neuroprotection by inhibiting neuronal cell damage/apoptosis, promoting nerve regeneration and repair, and restoring bioenergy following energy depletion caused by glutamate excitotoxicity.

Cell therapy with human MSCs isolated from the umbilical cord Wharton jelly associated to a PVA membrane in the treatment of chronic skin wounds

The healing process of the skin is a dynamic procedure mediated through a complex feedback of growth factors secreted by a variety of cells types. Despite the most recent advances in wound healing management and surgical procedures, these techniques still fail up to 50%, so cellular therapies involving mesenchymal stem cells (MSCs) are nowadays a promising treatment of skin ulcers which are a cause of high morbidity. The MSCs modulate the inflammatory local response and induce cell replacing, by a paracrine mode of action, being an important cell therapy for the impaired wound healing. The local application of human MSCs (hMSCs) isolated from the umbilical cord Wharton's jelly together with a poly(vinyl alcohol) hydrogel (PVA) membrane, was tested to promote wound healing in two dogs that were referred for clinical examination at UPVET Hospital, showing non-healing large skin lesions by the standard treatments. The wounds were infiltrated with 1000 cells/µl hMSCs in a total volume of 100 µl per cm(2) of lesion area. A PVA membrane was applied to completely cover the wound to prevent its dehydration. Both animals after the treatment demonstrated a significant progress in skin regeneration with decreased extent of ulcerated areas confirmed by histological analysis. The use of Wharton's jelly MSCs associated with a PVA membrane showed promising clinical results for future application in the treatment of chronic wounds in companion animals and humans.

Application of Umbilical Cord Blood Derived Stem Cells in Diseases of the Nervous System

Umbilical cord blood (UCB) derived multipotent stem cells are capable of giving rise hematopoietic, epithelial, endothelial and neural progenitor cells. Thus suggested to significantly improve graft-versus-host disease and represent the distinctive therapeutic option for several malignant and non-malignant diseases. Recent advances in strategies to isolate, expand and shorten the timing of UCB stem cells engraftment have tremendously improved the efficacy of transplantations. Nervous system has limited regenerative potential in disease conditions such as cancer, neurodegeneration, stroke, and several neural injuries. This review focuses on application of UCB derived stem/progenitor cells in aforementioned pathological conditions. We have discussed the possible attempts to make use of UCB therapies to generate neural cells and tissues with developmental and functional similarities to neuronal cells. In addition, emerging applications of UCB derived AC133+ (CD133+) endothelial progenitor cells (EPCs) as imaging probe, regenerative agent, and gene delivery vehicle are mentioned that will further improve the understanding of use of UCB cells in therapeutic modalities. However, safe and effective protocols for cell transplantations are still required for therapeutic efficacy.

Very small embryonic-like stem cells (VSELs) represent a real challenge in stem cell biology: recent pros and cons in the midst of a lively debate

The concept that adult tissue, including bone marrow (BM), contains early-development cells with broader differentiation potential has again been recently challenged. In response, we would like to review the accumulated evidence from several independent laboratories that adult tissues, including BM, harbor a population of very rare stem cells that may cross germ layers in their differentiation potential. Thus, the BM stem cell compartment hierarchy needs to be revisited. These dormant, early-development cells that our group described as very small embryonic-like stem cells (VSELs) most likely overlap with similar populations of stem cells that have been identified in adult tissues by other investigators as the result of various experimental strategies and have been given various names. As reported, murine VSELs have some pluripotent stem cell characteristics. Moreover, they display several epiblast/germline markers that suggest their embryonic origin and developmental deposition in adult BM. Moreover, at the molecular level, changes in expression of parentally imprinted genes (for example, Igf2–H19) and resistance to insulin/insulin-like growth factor signaling (IIS) regulates their quiescent state in adult tissues. In several emergency situations related to organ damage, VSELs can be activated and mobilized into peripheral blood, and in appropriate animal models they contribute to tissue organ/regeneration. Interestingly, their number correlates with lifespan in mice, and they may also be involved in some malignancies. VSELs have been successfully isolated in several laboratories; however, some investigators experience problems with their isolation.

Adult bone marrow neural crest stem cells and mesenchymal stem cells are not able to replace lost neurons in acute MPTP-lesioned mice

Adult bone marrow stroma contains multipotent stem cells (BMSC) that are a mixed population of mesenchymal and neural-crest derived stem cells. Both cells are endowed with in vitro multi-lineage differentiation abilities, then constituting an attractive and easy-available source of material for cell therapy in neurological disorders. Whereas the in vivo integration and differentiation of BMSC in neurons into the central nervous system is currently matter of debate, we report here that once injected into the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, pure populations of either bone marrow neural crest stem cells (NCSC) or mesenchymal stem cells (MSC) survived only transiently into the lesioned brain. Moreover, they do not migrate through the brain tissue, neither modify their initial phenotype, while no recovery of the dopaminergic system integrity was observed. Consequently, we tend to conclude that MSC/NCSC are not able to replace lost neurons in acute MPTP-lesioned dopaminergic system through a suitable integration and/or differentiation process. Altogether with recent data, it appears that neuroprotective, neurotrophic and anti-inflammatory features characterizing BMSC are of greater interest as regards CNS lesions management.

Evidence for bone marrow adult stem cell plasticity: properties, molecular mechanisms, negative aspects, and clinical applications of hematopoietic and mesenchymal stem cells transdifferentiation

In contrast to the pluripotent embryonic stem cells (ESCs) which are able to give rise to all cell types of the body, mammalian adult stem cells (ASCs) appeared to be more limited in their differentiation potential and to be committed to their tissue of origin. Recently, surprising new findings have contradicted central dogmas of commitment of ASCs by showing their plasticity to differentiate across tissue lineage boundaries, irrespective of classical germ layer designations. The present paper supports the plasticity of the bone marrow stem cells (BMSCs), bringing the most striking and the latest evidences of the transdifferentiation properties of the bone marrow hematopoietic and mesenchymal stem cells (BMHSCs, and BMMSCs), the two BM populations of ASCs better characterized. In addition, we report the possible mechanisms that may explain these events, outlining the clinical importance of these phenomena and the relative problems.