Placental mesenchymal and cord blood stem cell therapy for dilated cardiomyopathy

Human Umbilical Cord Mesenchymal Stem Cells: Current Literature and Role in Periodontal Regeneration

Periodontal disease can cause irreversible damage to tooth-supporting tissues such as the root cementum, periodontal ligament, and alveolar bone, eventually leading to tooth loss. While standard periodontal treatments are usually helpful in reducing disease progression, they cannot repair or replace lost periodontal tissue. Periodontal regeneration has been demonstrated to be beneficial in treating intraosseous and furcation defects to varied degrees. Cell-based treatment for periodontal regeneration will become more efficient and predictable as tissue engineering and progenitor cell biology advance, surpassing the limitations of present therapeutic techniques. Stem cells are undifferentiated cells with the ability to self-renew and differentiate into several cell types when stimulated. Mesenchymal stem cells (MSCs) have been tested for periodontal regeneration in vitro and in humans, with promising results. Human umbilical cord mesenchymal stem cells (UC-MSCs) possess a great regenerative and therapeutic potential. Their added benefits comprise ease of collection, endless source of stem cells, less immunorejection, and affordability. Further, their collection does not include the concerns associated with human embryonic stem cells. The purpose of this review is to address the most recent findings about periodontal regenerative mechanisms, different stem cells accessible for periodontal regeneration, and UC-MSCs and their involvement in periodontal regeneration.

Biofabrication in Congenital Cardiac Surgery: A Plea from the Operating Theatre, Promise from Science

Despite significant advances in numerous fields of biofabrication, clinical application of biomaterials combined with bioactive molecules and/or cells largely remains a promise in an individualized patient settings. Three-dimensional (3D) printing and bioprinting evolved as promising techniques used for tissue-engineering, so that several kinds of tissue can now be printed in layers or as defined structures for replacement and/or reconstruction in regenerative medicine and surgery. Besides technological, practical, ethical and legal challenges to solve, there is also a gap between the research labs and the patients' bedside. Congenital and pediatric cardiac surgery mostly deal with reconstructive patient-scenarios when defects are closed, various segments of the heart are connected, valves are implanted. Currently available biomaterials lack the potential of growth and conduits, valves derange over time surrendering patients to reoperations. Availability of viable, growing biomaterials could cancel reoperations that could entail significant public health benefit and improved quality-of-life. Congenital cardiac surgery is uniquely suited for closing the gap in translational research, rapid application of new techniques, and collaboration between interdisciplinary teams. This article provides a succinct review of the state-of-the art clinical practice and biofabrication strategies used in congenital and pediatric cardiac surgery, and highlights the need and avenues for translational research and collaboration.

Mtu1 defects are correlated with reduced osteogenic differentiation

Accumulating evidence has revealed that mitochondria dynamics and function regulation is essential for the successful mesenchymal stem cell (MSC) differentiation. In the present study, the researchers reported for the first time that Mtu1 defects are correlated with reduced osteogenic differentiation. Using in vitro cultured bone marrow MSCs and stromal cell line MS5, we demonstrated that depressed Mtu1 expression was associated with reduced 2-thiouridine modification of the U34 of mitochondrial tRNA^Gln, tRNA^Glu, and tRNA^Lys, which led to respiratory deficiencies and reduced mitochondrial ATP production, and finally suppressed osteogenic differentiation. As expected, these Mtu1-deficient mice exhibited obvious osteopenia. Therefore, our findings in this study provide new insights into the pathophysiology of osteopenia.

Umbilical cord stem cells: Background, processing and applications

Stem cells have currently gained attention in the field of medicine not only due to their ability to repair dysfunctional or damaged cells, but also they could be used as drug delivery system after being engineered to do so. Human umbilical cord is attractive source for autologous and allogenic stem cells that are currently amenable to treatment of various diseases. Human umbilical cord stem cells are -in contrast to embryonic and fetal stem cells- ethically noncontroversial, inexpensive and readily available source of cells. Umbilical cord, umbilical cord vein, amnion/placenta and Wharton's jelly are all rich of many types of multipotent stem cell populations capable of forming many different cell types. This review will focus on umbilical cord stem cells processing and current application in medicine.

Umbilical cord-derived mesenchymal stromal cells in cardiovascular disease: review of preclinical and clinical data

The human umbilical cord has recently emerged as an attractive potential source of mesenchymal stromal cells (MSCs) to be adopted for use in regenerative medicine. Umbilical cord MSCs (UC-MSCs) not only share the same features of all MSCs such as multi-lineage differentiation, paracrine functions and immunomodulatory properties, they also have additional advantages, such as no need for bone marrow aspiration and higher self-renewal capacities. They can be isolated from various compartments of the umbilical cord (UC) and can be used for autologous or allogeneic purposes. In the past decade, they have been adopted in cardiovascular disease and have shown promising results mainly due to their pro-angiogenic and anti-inflammatory properties. This review offers an overview of the biological properties of UC-MSCs describing available pre-clinical and clinical data with respect to their potential therapeutic use in cardiovascular regeneration, with current challenges and future directions discussed.

Cell-Based Therapy Using Umbilical Cord Blood for Novel Indications in Regenerative Therapy and Immune Modulation: An Updated Systematic Scoping Review of the Literature

Cell-based therapy using umbilical cord blood (UCB) is being used increasingly in novel applications. To balance heightened public expectations and ensure appropriateness of emerging cell-based treatment choices, regular evidence-based assessment of novel UCB-derived therapies is needed. We performed a systematic search of the literature and identified 57 studies (814 patients) for analysis. Sixteen of these studies (353 patients) included a control group for comparison. The most commonly reported novel indication for therapy was neurologic diseases (25 studies, 476 patients), including studies of cerebral palsy (12 studies, 276 patients). Other indications included diabetes mellitus (9 studies, 149 patients), cardiac and vascular diseases (7 studies, 24 patients), and hepatic diseases (4 studies, 106 patients). Most studies administered total nucleated cells, mononuclear cells, or CD34-selected cells (31 studies, 513 patients), whereas 20 studies described the use of UCB-derived mesenchymal stromal cells. The majority of reports (46 studies, 627 patients) described cellular products obtained from allogeneic sources, whereas 11 studies (187 patients) used autologous products. We identified 3 indications where multiple prospective controlled studies have been published: 4 of 4 studies reported clinical benefit in cerebral palsy, 1 of 3 studies reported benefit for cirrhosis, and 1 of 3 studies reported biochemical response in type 1 diabetes), although heterogeneity among the studies precluded meaningful pooled analysis of results. We anticipate a more clear understanding of the clinical benefit for specific indications once more controlled studies are reported. Patients should continue to be enrolled on registered clinical trials for novel therapies. Blood establishments, transplantation centers, and regulatory bodies need to prepare for greater clinical demand.

A Prospective, Nonrandomized, no Placebo-Controlled, Phase I/II Clinical Trial Assessing the Safety and Efficacy of Intramuscular Injection of Autologous Adipose Tissue-Derived Mesenchymal Stem Cells in Patients With Severe Buerger's Disease

Buerger's disease is a rare and severe disease affecting the blood vessels of the limbs. Adipose tissue-derived mesenchymal stem cells (ADSCs) have the potential to cure Buerger's disease when developed as a stem cell drug. In the present study, we conducted a prospective, nonrandomized, no placebo-controlled, phase I/II clinical trial with a 2-year follow-up questionnaire survey. A total of 17 patients were intramuscularly administered autologous ADSCs at a dose of 5 million cells/kg. The incidence of adverse events (AEs), adverse drug reaction (ADR), and serious adverse events (SAEs) was monitored. No ADRs and SAEs related to stem cell treatment occurred during the 6-month follow-up. In terms of efficacy, the primary endpoint was increase in total walking distance (TWD). The secondary endpoint was improvement in rest pain, increase in pain-free walking distance (PFWD), toe-brachial pressure index (TBPI), transcutaneous oxygen pressure (TcPO₂), and arterial brachial pressure index (ABPI). ADSCs demonstrated significant functional improvement results including increased TWD, PFWD, and rest pain reduction. No amputations were reported during the 6-month clinical trial period and in the follow-up questionnaire survey more than 2 years after the ADSC injection. In conclusion, intramuscular injection of ADSCs is very safe and is shown to prompt functional improvement in patients with severe Buerger's disease at a dosage of 300 million cells per 60 kg of body weight. However, the confirmatory therapeutic efficacy and angiogenesis need further study.

Umbilical cord blood-derived mesenchymal stem cells: new therapeutic weapons for idiopathic dilated cardiomyopathy?

Dilated cardiomyopathy is the most frequent etiology of non-ischemic heart failure. In a majority of cases the causal mechanism is unknown, giving rise to the term 'idiopathic' dilated cardiomyopathy (IDCM). Major pathological derangements include patchy interstitial fibrosis, degenerated cardiomyocytes, and dilatation of the cardiac chambers, but recent evidence suggests that disease progression may also have the signature of cardiac endothelial dysfunction. As we better understand the molecular basis of IDCM, novel therapeutic approaches, mainly gene transfer and cell-based therapies, are being explored. Cells with regenerative potential have been extensively tested in cardiac diseases of ischemic origin in both pre-clinical and clinical settings. However, whether cell therapy has any clinical value in IDCM patients is still being evaluated. This article is a concise summary of cell therapy studies for IDCM, with a focus on recent advances that highlight the vascular potential exhibited by umbilical cord blood-derived mesenchymal stem cells (UCBMSCs). We also provide an overview of cardiac vasculature as a key regulator of subjacent myocardial integrity and function, and discuss the potential mechanisms of UCBMSC amelioration of IDCM myocardium. Consideration of these issues shows that these cells are conceivably new therapeutic agents for this complex and elusive human disorder.

Infusion of autologous bone marrow mononuclear cells leads to transient reduction in proteinuria in treatment refractory patients with Idiopathic membranous nephropathy

Background

The current treatment options for idiopathic membranous nephropathy (IMN) carry significant toxicity. In this prospective, observational pilot study, we used single time infusion of bone marrow derived autologous mononuclear cells (MNCs) in adult patients with treatment refractory IMN.

Methods

Twelve patients of biopsy proven IMN who had failed a cyclical 6-month regimen of steroid and cyclophosphamide were enrolled in the study. Bone-marrow was harvested from the iliac crest and underwent processing to isolate MNCs. Cells were counted and subjected to viability testing before being infused through a peripheral vein on the same day. After the infusion, subjects were followed up monthly for the next six months. Supportive treatment including angiotensin antagonists and statins was continued throughout the study period.

Result

The proteinuria, serum albumin and creatinine values at entry were 2.97 ± 0.6 gm/1.73 m²/d, 2.27 ± 1.1 gm/l and 0.9 ± 0.8 mg/dl respectively. There was a reduction in proteinuria (p < 0.0001), and increase in serum albumin (p = 0.001) at 1 month, with 64% of the subjects showing >50% reduction in proteinuria. However, the response was ill sustained. At 6 months, only 2 patients had >50% reduction. Serum creatinine remained stable throughout the study period. No infusion related side effects were noted.

Conclusion

Autologous mononuclear cell infusion leads to transitory reduction in proteinuria and improvement in serum albumin in treatment refractory IMN. This effect, however, is transient. Whether this can be overcome by repeated infusion of cultured mesenchymal cells needs to be investigated.

Transplantation of umbilical cord blood-derived cells for novel indications in regenerative therapy or immune modulation: a scoping review of clinical studies

Although used mainly for transplantation of hematopoietic stem cells in the treatment of blood disorders, umbilical cord blood (UCB)-based therapies are now being used increasingly for novel applications in nonhematopoietic diseases and as a form of cellular regenerative therapy or immune modulation. We performed a systematic scoping review by searching Medline, EMBASE, and the Cochrane Library for published articles, and we searched www.clinicaltrials.com and the World Health Organization International Clinical Trials Registry Platform to describe the breadth of published studies and ongoing clinical activity in umbilical cord-based cellular therapy for regenerative therapy and immune modulation. The most commonly published area of expertise in the use of UCB-derived cellular transplantation for novel indications is for neurological disorders and this remains the most active area of study in ongoing registered trials. An increasingly broad range of disorders, however, are reflected in ongoing registered trials, which suggests greater activity, interest, and investment in UCB-derived cellular therapy. Interestingly, adult patients compose the majority of patients reported in published reports and registered ongoing clinical studies continue to enroll predominantly adult subjects. Geographically, Asian countries appear most active in UCB-derived cellular therapy and our analysis of ongoing studies suggests this trend will likely continue. Regular assessment of published and ongoing activity in UCB transplantation for emerging novel indications will be critical for informing UCB banking establishments and funding agencies to guide changes in banking practices related to emerging trends in cell therapy.

Toward the use of endometrial and menstrual blood mesenchymal stem cells for cell-based therapies

INTRODUCTION

Bone marrow is a widely used source of mesenchymal stem cells (MSCs) for cell-based therapies. Recently, endometrium - the highly regenerative lining of the uterus - and menstrual blood have been identified as more accessible sources of MSCs. These uterine MSCs include two related cell types: endometrial MSCs (eMSCs) and endometrial regenerative cells (ERCs).

AREAS COVERED

The properties of eMSCs and ERCs and their application in preclinical in vitro and in vivo studies for pelvic organ prolapse, heart disorders and ischemic conditions are reviewed. Details of the first clinical Phase I and Phase II studies will be provided.

EXPERT OPINION

The authors report that eMSCs and ERCs are a readily available source of adult stem cells. Both eMSCs and ERCs fulfill the key MSC criteria and have been successfully used in preclinical models to treat various diseases. Data on clinical trials are sparse. More research is needed to determine the mechanism of action of eMSCs and ERCs in these regenerative medicine models and to determine the long-term benefits and any adverse effects after their administration.

Clinical applications of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are self-renewing, multipotent progenitor cells with multilineage potential to differentiate into cell types of mesodermal origin, such as adipocytes, osteocytes, and chondrocytes. In addition, MSCs can migrate to sites of inflammation and exert potent immunosuppressive and anti-inflammatory effects through interactions between lymphocytes associated with both the innate and adaptive immune system. Along with these unique therapeutic properties, their ease of accessibility and expansion suggest that use of MSCs may be a useful therapeutic approach for various disorders. In the clinical setting, MSCs are being explored in trials of various conditions, including orthopedic injuries, graft versus host disease following bone marrow transplantation, cardiovascular diseases, autoimmune diseases, and liver diseases. Furthermore, genetic modification of MSCs to overexpress antitumor genes has provided prospects for clinical use as anticancer therapy. Here, we highlight the currently reported uses of MSCs in clinical trials and discuss their efficacy as well as their limitations.

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.

Beneficial effects of non-matched allogeneic cord blood mononuclear cells upon patients with idiopathic osteoporosis

Background

Immunological arguments and historical examples have shown that treatment with cord blood for non-hematopoietic activities, such as growth factor production and stimulation of angiogenesis, may not require matching or immune suppression.

Methods

To study the benefit of blood mononuclear cell therapy, 8 patients with idiopathic osteoporosis were given intermittent treatments with non-matched allogeneic cord blood mononuclear cells for 3 months. Morning fasting samples were collected for measuring urine N telopeptide of type-1 collagen, serum bone-specific alkaline phosphatase, and insulin-like growth factor 1 during one-year study.

Results

Clinical response was striking. Serum insulin-like growth factor 1 significantly increased in all patients at 3 months compared with baseline values, from 264.1 ± 107.0 to 384.4 ± 63.1 ng/mL (P = 0.002), with a tendency to return to baseline values at 12 months (312.9 ± 75.5 ng/mL, P = 0.083). In contrast, differences in serum bone-specific alkaline phosphatase and urine N telopeptide of type-1 collagen were not significant at 3 (P = 0.765, P = 0.057) or 12 months (P = 0.889, P = 0.122). A beneficial effect on bone density was observed in all patients at the lumbar spine. The mean bone mineral density calculated during therapy (0.6811 ± 0.1442 g/cm²) tended higher than baseline values (0.6239 ± 0.1362 g/cm², P < 0), and percentage change (median) varied from 8.85% at 3 months to 7.85% at one year. All patients are now well after one year.

Conclusions

The findings indicate that for these patients with idiopathic osteoporosis, treatment with cord blood mononuclear cells led to a significant increase in insulin-like growth factor 1 levels, which favors the increase in bone mineral density.

Uric acid promotes neuronal differentiation of human placenta-derived mesenchymal stem cells in a time- and concentration-dependent manner

Uric acid is an important, naturally occurring serum antioxidant. The present study investigates the use of uric acid for promoting proliferation and neuronal differentiation of mesenchymal stem cells derived from human placenta tissue. Human placenta-derived mesenchymal stem cells were pre-induced in the presence of either 0, 0.2, 0.4 or 0.8 mM uric acid in combination with 1 mM β-mercaptoethanol for 24 hours, followed by exposure to identical uric acid concentrations and 5 mM β-mercaptoethanol for 6 and 10 hours. Cells developed a neuronal-like morphology, with formation of interconnected process extensions, typical of neural cells. Immunocytochemistry and immunofluorescence staining showed neuron specific enolase positive cells were present in each group except the control group. A greater number of neuron specific enolase positive cells were observed in 0.8 mM uric acid in combination with 5 mM β-mercaptoethanol at 10 hours. After 24 hours of induction, Nissl bodies were detected in the cytoplasm of all differentiated cell groups except the control group and Nissl body numbers were greatest in human placenta-derived mesenchymal stem cells grown in the presence of 0.8 mM uric acid and 5 mM β-mercaptoethanol. These results suggest uric acid accelerates differentiation of human placenta-derived mesenchymal stem cells into neuronal-like cells in a time- and concentration-dependent manner.

Mesenchymal stem cells for cardiac cell therapy

Despite refinements of medical and surgical therapies, heart failure remains a fatal disease. Myocardial infarction is the most common cause of heart failure, and only palliative measures are available to relieve symptoms and prolong the patient's life span. Because mammalian cardiomyocytes irreversibly exit the cell cycle at about the time of birth, the heart has traditionally been considered to lack any regenerative capacity. This paradigm, however, is currently shifting, and the cellular composition of the myocardium is being targeted by various regeneration strategies. Adult progenitor and stem cell treatment of diseased human myocardium has been carried out for more than 10 years (Menasche et al., 2001; Stamm et al., 2003), and it has become clear that, in humans, the regenerative capacity of hematopoietic stem cells and endothelial progenitor cells, despite potent proangiogenic effects, is limited (Stamm et al., 2009). More recently, mesenchymal stem cells (MSCs) and related cell types are being evaluated in preclinical models of heart disease as well as in clinical trials (see Published Clinical Trials, below). MSCs have the capacity to self-renew and to differentiate into lineages that normally originate from the embryonic mesenchyme (connective tissues, blood vessels, blood-related organs) (Caplan, 1991; Prockop, 1997; Pittenger et al., 1999). The current definition of MSCs includes plastic adherence in cell culture, specific surface antigen expression (CD105(+)/CD90(+)/CD73(+), CD34(-)/CD45(-)/CD11b(-) or CD14(-)/CD19(-) or CD79α(-)/HLA-DR1(-)), and multilineage in vitro differentiation potential (osteogenic, chondrogenic, and adipogenic) (Dominici et al., 2006 ). If those criteria are not met completely, the term "mesenchymal stromal cells" should be used for marrow-derived adherent cells, or other terms for MSC-like cells of different origin. For the purpose of this review, MSCs and related cells are discussed in general, and cell type-specific properties are indicated when appropriate. We first summarize the preclinical data on MSCs in models of heart disease, and then appraise the clinical experience with MSCs for cardiac cell therapy.

Feasibility of combination allogeneic stem cell therapy for spinal cord injury: a case report

Cellular therapy for spinal cord injury (SCI) is overviewed focusing on bone marrow mononuclear cells, olfactory ensheathing cells, and mesenchymal stem cells. A case is made for the possibility of combining cell types, as well as for allogeneic use. We report the case of 29 year old male who suffered a crush fracture of the L1 vertebral body, lacking lower sensorimotor function, being a score A on the ASIA scale. Stem cell therapy comprised of intrathecal administration of allogeneic umbilical cord blood ex-vivo expanded CD34 and umbilical cord matrix MSC was performed 5 months, 8 months, and 14 months after injury. Cell administration was well tolerated with no adverse effects observed. Neuropathic pain subsided from intermittent 10/10 to once a week 3/10 VAS. Recovery of muscle, bowel and sexual function was noted, along with a decrease in ASIA score to "D". This case supports further investigation into allogeneic-based stem cell therapies for SCI.

Mesenchymal stromal cells from human perinatal tissues: From biology to cell therapy

Cell-based regenerative medicine is of growing interest in biomedical research. The role of stem cells in this context is under intense scrutiny and may help to define principles of organ regeneration and develop innovative therapeutics for organ failure. Utilizing stem and progenitor cells for organ replacement has been conducted for many years when performing hematopoietic stem cell transplantation. Since the first successful transplantation of umbilical cord blood to treat hematological malignancies, non-hematopoietic stem and progenitor cell populations have recently been identified within umbilical cord blood and other perinatal and fetal tissues. A cell population entitled mesenchymal stromal cells (MSCs) emerged as one of the most intensely studied as it subsumes a variety of capacities: MSCs can differentiate into various subtypes of the mesodermal lineage, they secrete a large array of trophic factors suitable of recruiting endogenous repair processes and they are immunomodulatory.Focusing on perinatal tissues to isolate MSCs, we will discuss some of the challenges associated with these cell types concentrating on concepts of isolation and expansion, the comparison with cells derived from other tissue sources, regarding phenotype and differentiation capacity and finally their therapeutic potential.

Safety evaluation of allogeneic umbilical cord blood mononuclear cell therapy for degenerative conditions

Background

The current paradigm for cord blood transplantation is that HLA matching and immune suppression are strictly required to prevent graft versus host disease (GVHD). Immunological arguments and historical examples have been made that the use of cord blood for non-hematopoietic activities such as growth factor production, stimulation of angiogenesis, and immune modulation may not require matching or immune suppression.

Methods

114 patients suffering from non-hematopoietic degenerative conditions were treated with non-matched, allogeneic cord blood. Doses of 1-3 × 10⁷ cord blood mononuclear cells per treatment, with 4-5 treatments both intrathecal and intravenously were performed. Adverse events and hematological, immunological, and biochemical parameters were analyzed for safety evaluation.

Results

No serious adverse effects were reported. Hematological, immunological, and biochemical parameters did not deviate from normal ranges as a result of therapy.

Conclusion

The current hematology-based paradigm of need for matching and immune suppression needs to be revisited when cord blood is used for non-hematopoietic regenerative purposes in immune competent recipients.

Hypoxia promotes efficient differentiation of human embryonic stem cells to functional endothelium

Early development of mammalian embryos occurs in an environment of relative hypoxia. Nevertheless, human embryonic stem cells (hESC), which are derived from the inner cell mass of blastocyst, are routinely cultured under the same atmospheric conditions (21% O(2)) as somatic cells. We hypothesized that O(2) levels modulate gene expression and differentiation potential of hESC, and thus, we performed gene profiling of hESC maintained under normoxic or hypoxic (1% or 5% O(2)) conditions. Our analysis revealed that hypoxia downregulates expression of pluripotency markers in hESC but increases significantly the expression of genes associated with angio- and vasculogenesis including vascular endothelial growth factor and angiopoitein-like proteins. Consequently, we were able to efficiently differentiate hESC to functional endothelial cells (EC) by varying O(2) levels; after 24 hours at 5% O(2), more than 50% of cells were CD34+. Transplantation of resulting endothelial-like cells improved both systolic function and fractional shortening in a rodent model of myocardial infarction. Moreover, analysis of the infarcted zone revealed that transplanted EC reduced the area of fibrous scar tissue by 50%. Thus, use of hypoxic conditions to specify the endothelial lineage suggests a novel strategy for cellular therapies aimed at repair of damaged vasculature in pathologies such as cerebral ischemia and myocardial infarction.

Combination stem cell therapy for heart failure

Patients with congestive heart failure (CHF) that are not eligible for transplantation have limited therapeutic options. Stem cell therapy such as autologous bone marrow, mobilized peripheral blood, or purified cells thereof has been used clinically since 2001. To date over 1000 patients have received cellular therapy as part of randomized trials, with the general consensus being that a moderate but statistically significant benefit occurs. Therefore, one of the important next steps in the field is optimization. In this paper we discuss three ways to approach this issue: a) increasing stem cell migration to the heart; b) augmenting stem cell activity; and c) combining existing stem cell therapies to recapitulate a "therapeutic niche". We conclude by describing a case report of a heart failure patient treated with a combination stem cell protocol in an attempt to augment beneficial aspects of cord blood CD34 cells and mesenchymal-like stem cells.

Cord blood-derived early outgrowth endothelial progenitor cells

The presence of circulating endothelial repopulating cells in the adult human peripheral blood has been proposed since long time ago. In the late 1990s, the putative endothelial progenitor cells (EPCs) were first identified and reported by Asahara and co-workers. Since then, a number of studies have demonstrated that these cells are derived from bone marrow and induce microvascular vasculogenesis and re-endothelialization of injured vessels. Meantime, human umbilical cord blood also gained much attention for the reason of possible additional source to obtain EPCs since cord blood has been shown to contain more number of active hematopoietic stem cells as compared to adult peripheral blood. This review summarizes the aspect of human cord blood-derived EPCs with special focuses into their identity and future clinical application.

Mesenchymal stem cells as anti-inflammatories: implications for treatment of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a lethal X-linked musculodegenerative condition consisting of an underlying genetic defect whose manifestation is augmented by inflammatory mechanisms. Previous treatment approaches using gene replacement, exon-skipping or allogeneic cell therapy have been relatively unsuccessful. The only intervention to mediate improvement in survival, albeit minor, is glucocorticoid treatment. Given this modality appears to function via suppression of underlying inflammation; we focus this review on the inflammatory response as a target for mesenchymal stem cell (MSC) therapy. In contrast to other cell based therapies attempted in DMD, MSC have the advantages of (a) ability to fuse with and genetically complement dystrophic muscle; (b) possess anti-inflammatory activities; and (c) produce trophic factors that may augment activity of endogenous repair cells. We conclude by describing one practical scenario of stem cell therapy for DMD.

Skeletal muscle-derived stem cells exhibit cardiocyte competences

Adult stem cells from skeletal muscle cells were induced to differentiate into cardiocytes to see if stem cells from another different but histologically-comparable tissues can differentiate to the target cells. Skeletal muscles-derived stem cells (MDSCs) were isolated from adult skeleton muscle tissues by differential adhesion, and immunocytochemically identified by using Sca-1. In order to induce the proliferation but not differentiation of MDSCs, the cells were cultured in Dulbecco's modified Eagle's medium/F12 (DMEM/F12) supplemented with 1:50 B27, 20 ng/mL basic fibroblast growth factor (bFGF), 20 ng/mL epidermal growth factor (EGF) in a suspension for 6 days. Then these stem cells were treated with 5 mumol/L 5-azacytidine for 24 h in an adherence culture. The characteristics of induced cells were examined by immunocytochemistry, quantitative real time RT-PCR and morphological observation of cell phenotype. Our results showed that the appearance of some cells gradually changed from spindle-shape into polygonal or short-column-shape. Some of these post-treated cells could contract spontaneously and rhythmically. The expression of GATA-4 and cTnT was increased 1 and 2 week(s) after the treatment. And about 16.6% of post-treated cells were cTnT-positive. Therefore, we are led to conclude that skeletal muscle-derived stem cells could differentiate into cardiocyte-like cells, which exhibited some characteristics of cardiocytes.

Effect of human umbilical cord blood cells on Ang-II-induced hypertrophy in mice

We have assessed the capacity of human umbilical cord blood (hUCB)-derived stem cells to differentiate into cardiomyocytes and repair angiotensin II induced insult in culture and in mouse hearts when injected. hUCB were able to differentiate into cardiomyocyte-like cells, when induced with 5-azacytidine or co-cultured with rat neonatal cardiomyocytes (NRCM). When co-cultured, hUCB reversed the pathological effects induced by angiotensin II (Ang-II) in NRCM and in mice injected after Ang-II infusion. As assessed by increased heart weight to body mass ratio and Ang-II-induced fibrosis, cardiac hypertrophy was also reduced after hUCB were injected. hUCB also reversed the pathological heart failure markers induced by Ang-II in mice. Further, we observed a shift from pathological hypertrophy towards physiological hypertrophy by hUCB in Ang-II-challenged mice. Our findings support hUCB as a feasible model for experimentation in stem cell therapy and emphasize the relevance of the hUCB in reversing heart failure conditions.

From embryonic stem cells to blastema and MRL mice

New scientific knowledge offers fresh opportunities for regenerative medicine and tissue repair. Among various clinical options, multipotent embryonic stem cells (ESC) prepared from inner cell masses of rabbit blastocysts have been tested over many years. More recently, stem cells have been isolated from individual tissues and from umbilical cord blood. These methods seemingly offer similar rates of repair and avoid ethical complexities arising from the need for human embryos to prepare ESC. Different methods of regenerating tissues have now emerged, based on the well-known forms of organ regeneration in urodeles such as salamanders. These methods depend on the formation of a blastema, and recent studies on MRL mice have revealed that they possess similar methods of repair as in salamanders. There is also some evidence showing that this form of repair is also active in human fetuses but not in adults. Detailed knowledge of these various forms of tissue repair is now urgently needed in order to assess the benefits of each form of treatment. These matters are discussed at the end of this review where various investigations clarify the benefits and drawbacks of these varied approaches to tissue repair.