Tissue-specific angiogenic and invasive properties of human neonatal thymus and bone MSCs: Role of SLIT3-ROBO1

Although mesenchymal stem/stromal cells (MSCs) are being explored in numerous clinical trials as proangiogenic and proregenerative agents, the influence of tissue origin on the therapeutic qualities of these cells is poorly understood. Complicating the functional comparison of different types of MSCs are the confounding effects of donor age, genetic background, and health status of the donor. Leveraging a clinical setting where MSCs can be simultaneously isolated from discarded but healthy bone and thymus tissues from the same neonatal patients, thereby controlling for these confounding factors, we performed an in vitro and in vivo paired comparison of these cells. We found that both neonatal thymus (nt)MSCs and neonatal bone (nb)MSCs expressed different pericytic surface marker profiles. Further, ntMSCs were more potent in promoting angiogenesis in vitro and in vivo and they were also more motile and efficient at invading ECM in vitro. These functional differences were in part mediated by an increased ntMSC expression of SLIT3, a factor known to activate endothelial cells. Further, we discovered that SLIT3 stimulated MSC motility and fibrin gel invasion via ROBO1 in an autocrine fashion. Consistent with our findings in human MSCs, we found that SLIT3 and ROBO1 were expressed in the perivascular cells of the neonatal murine thymus gland and that global SLIT3 or ROBO1 deficiency resulted in decreased neonatal murine thymus gland vascular density. In conclusion, ntMSCs possess increased proangiogenic and invasive behaviors, which are in part mediated by the paracrine and autocrine effects of SLIT3.

Mesenchymal stem or stromal cells: a review of clinical applications and manufacturing practices

Mesenchymal stem cells (MSCs) have recently generated great interest in the fields of regenerative medicine and immunotherapy due to their unique biologic properties. In this review we attempt to provide an overview of the current clinical status of MSC therapy, primarily focusing on immunomodulatory and regenerative or tissue repair applications of MSCs. In addition, current manufacturing is reviewed with attention to variation in practices (e.g., starting material, approach to culture and product testing). There is considerable variation among the 218 clinical trials assessed here; variations include proposed mechanisms of action, optimal dosing strategy, and route of administration. To ensure the greatest likelihood of success in clinical trials as the field progresses, attention must be given to the optimization of MSC culture.

Intracavernous administration of bone marrow mononuclear cells: a new method of treating erectile dysfunction?

While PDE5 inhibitors have revolutionized treatment of ED, approximately 30% of patients are non-responsive. A significant cause of this is vascular and smooth muscle dysfunction, as well as nerve atrophy. Autologous administration of bone marrow mononuclear cells (BMMC) has been performed in over 2000 cardiac patients without adverse effects, for stimulation of angiogenesis/regeneration. Despite its ease of access, and dependence on effective vasculature for function, comparatively little has been perform in terms of BMMC therapy for ED. Here we outline the rationale for use of autologous BMMC in patients with ED, as well as provide early safety data on the first use of this procedure clinically.

Effects of Storage Solutions on the Viability of Human Umbilical Cord Mesenchymal Stem Cells for Transplantation

Human umbilical cord-derived mesenchymal stem cell (UC-MSC) transplantation has shown promise for the treatment of various diseases. For clinical applications, UC-MSCs have been stored in 0.9% saline, 5% dextrose, dextrose and sodium chloride injection, Plasma-Lyte A, 1% human serum albumin (1% HSA), or 5% HSA before administration, but the effect of storage conditions on the viability and biological function of the cells remains unknown. Freshly harvested UC-MSCs were resuspended and incubated in these solutions for 2, 4, or 6 h at 4°C or room temperature (24°C). Cell viability, apoptotic/necrotic fraction, poststorage growth potential, immunophenotype, immunosuppressive capacity, and differentiation capacity were analyzed. When stored in parenteral solutions, UC-MSCs showed progressive deterioration in survival viability and adhesion ability. After 6-h storage, the best viability and attachment rate of UC-MSCs decreased to 83.0 ± 1.6% and 71.8 ± 3.2%, respectively. Our results suggested that UC-MSCs in these conditions lose their viability in a short time. However, it seems that the other biological functions of the surviving UC-MSCs were little affected. Since UC-MSCs suspended in these mediums lose their survival viability in a short time to levels significantly below the permissible limits (70%) by FDA, precautions need to be taken on using these solutions as suspension medium and further studies on the optimal methods for preservation are urgent.

The potential of human fetal mesenchymal stem cells for off-the-shelf bone tissue engineering application

Mesenchymal stem cells (MSCs) have become one of the most promising cell sources for bone tissue engineering (BTE) applications. In this review, we first highlight recent progress in the understanding of MSC biology, their in vivo niche, multi-faceted contribution to fracture healing and bone re-modelling, and their role in BTE. A literature review from clinicaltrials.gov and Pubmed on clinical usage of MSC for both orthopedic and non-orthopedic indications suggests that translational use of MSC for BTE indications is likely to bear fruit in the ensuing decade. Last, we disscuss the profound influence of ontological and antomical origins of MSC on their proliferation and osteogenesis and demonstrated human fetal MSC (hfMSC) as a superior cellular candidate for off-the-shelf BTE applications. This relates to their superior proliferation capacity, more robust osteogenic potential and lower immunogenecity, as compared to MSC from perinatal and postnatal sources. Furthermore, we discuss our experience in developing a hfMSC based BTE strategy with the integrated use of bioreactor-based dynamic priming within macroporous scaffolds, now ready for evaluation in clinical trials. In conclusion, hfMSC is likely the most promising cell source for allogeneic based BTE application, with proven advantages compared to other MSC based ones.

The mobilization of autologous bone marrow stem cells in the treatment of heart failure with Chinese medicine

Heart failure (HF) is a severe heart disease. The use of autologous bone marrow stem cells (BMCs) mobilization in the treatment of HF has been a hot topic to research both in Western medicine and Chinese medicine (CM). There are many clinical trials and experiments on study of BMCs mobilization for HF therapy, including integrative medicine. The effect of BMCs mobilization is favorable for cardiac repair, while some advantages of CM support the advanced study of its application in BMCs mobilization to treat HF. In addition, with mechanisms of autologous BMCs mobilization for the treatment of HF that will be revealed in the future, especially stem cells niches, integrative medicine would play an important role in this clinical thought of therapy model gradually. Simultaneously, CM should adapt the new approaches of stem cells progresses on HF treatment as holding characteristics of itself.

Myocardial remodeling: cellular and extracellular events and targets

The focus of this review is on translational studies utilizing large-animal models and clinical studies that provide fundamental insight into cellular and extracellular pathways contributing to post-myocardial infarction (MI) left ventricle (LV) remodeling. Specifically, both large-animal and clinical studies have examined the potential role of endogenous and exogenous stem cells to alter the course of LV remodeling. Interestingly, there have been alterations in LV remodeling with stem cell treatment despite a lack of long-term cell engraftment. The translation of the full potential of stem cell treatments to clinical studies has yet to be realized. The modulation of proteolytic pathways that contribute to the post-MI remodeling process has also been examined. On the basis of recent large-animal studies, there appears to be a relationship between stem cell treatment post-MI and the modification of proteolytic pathways, generating the hypothesis that stem cells leave an echo effect that moderates LV remodeling.

Culture media for the differentiation of mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) can be isolated from various tissues such as bone marrow aspirates, fat or umbilical cord blood. These cells have the ability to proliferate in vitro and differentiate into a series of mesoderm-type lineages, including osteoblasts, chondrocytes, adipocytes, myocytes and vascular cells. Due to this ability, MSCs provide an appealing source of progenitor cells which may be used in the field of tissue regeneration for both research and clinical purposes. The key factors for successful MSC proliferation and differentiation in vitro are the culture conditions. Hence, we here summarize the culture media and their compositions currently available for the differentiation of MSCs towards osteogenic, chondrogenic, adipogenic, endothelial and vascular smooth muscle phenotypes. However, optimal combination of growth factors, cytokines and serum supplements and their concentration within the media is essential for the in vitro culture and differentiation of MSCs and thereby for their application in advanced tissue engineering.

Bone marrow stem cells in clinical application: harnessing paracrine roles and niche mechanisms

The being of any individual throughout life is a dynamic process relying on the capacity to retain processes of self-renewal and differentiation, both of which are hallmarks of stem cells. Although limited in the adult human organism, regeneration and repair do take place in virtue of the presence of adult stem cells. In the bone marrow, two major populations of stem cells govern the dynamic equilibrium of both hemopoiesis and skeletal homeostasis; the hematopoietic and the mesenchymal stem cells. Recent cell based clinical trials utilizing bone marrow-derived stem cells as therapeutic agents have revealed promising results, while others have failed to display as such. It is therefore imperative to strive to understand the mechanisms by which these cells function in vivo, how their properties can be maintained ex-vivo, and to explore further their recently highlighted immunomodulatory and trophic effects.