Current Stem Cell Research & Therapy - Volume 9, Issue 6, 2014

Stem cell treatment or therapy is gaining interest as future medicine to treat several dreadful diseases/disorders. Especially mesenchymal stem cells (MSCs) derived from both embryonic and adult cell sources have shown tremendous impact on improving human health. These MSCs have evolved into intensely studied research subjects and clearly collected a great deal of experimental data in the past decade. Even after all these years, research on MSCs still remains a hot and happening area with lot many questions to be answered. In this direction, in our special issue we discussed the safety issue of MSCs as allogenic transplant subject (Sarah Broeckx et al.) and their differentiation potential into cartilage (Vuk Savkovic et al.). We also discussed how nanobiomaterials influence the stem cell modulation (Kiran Kumar Bokara) and how the signaling molecules and signaling pathways influence MSCs fate in regenerative medicine (Rama Raju Baadhe et al. and Birru Bhaskar et al.). In this special issue we also highlighted MSC’s interaction and interference with cancer cells (Chinnapandi Bharathiraja et al.). To the end we discussed advanced bone marrow aspiration by perfusion reactor system.

It has been reported that mesenchymal stem cells (MSCs) have homing capacities and immunomodulating effects after an intravenous injection. However, transplanting MSCs in murine tail veins can result in pulmonary reactions and even death of the animals. Unfortunately, only a few intravenous MSC transplantations have been reported in large animal species and these were performed in a limited number of individuals. To assess the safety of MSC transplantations, a large study on 291 recipient horses is reported here. MSCs were isolated from the peripheral blood (PB) of a 4-year-old and 6-year-old donor horse after having tested their PB for a wide range of transmittable diseases. The MSC samples from both donor horses were characterized and resuspended in 1ml of Dulbecco’s Modified Eagle Medium (DMEM) supplemented with 10% Dimethyl Sulfoxide (DMSO). After hand-thawing in the field, 291 horses with ages ranging from 3-months to 33-years were directly injected into their jugular vein. 281 horses (97%) received a single injection of a physiological dose of 0.2 x106 MSCs, 5 horses (1.7%) were re-injected after approximately 6 weeks (using the same dose and donor cells) and a single superphysiological dose of 106 MSCs was administered to 5 horses as well. In total, 176 recipients were injected with MSCs from the 4-year-old donor and 115 recipients received MSCs from the 6-year-old donor. From all the injected horses (n=291) no acute clinical adverse effects were noticed. Apart from one horse that died of colic 7 months after the treatment, no deaths were registered and all the horses were monitored for 1 year after the injection. In conclusion, no adverse effects were noticed in 291 recipients after an intravenous injection of allogenic PBderived MSCs. Nevertheless, further research is warranted in order to verify the immunogenic properties of these cells after allogenic transplantation into various (patho)physiological sites.

Stem cells, either neural [NSCs] or mesenchymal [MSCs], possess tremendous untapped potential for cell therapy. Unlike the NSCs, MSCs are multi-potent and they have high self-renewal capability and broad tissue distribution. Since they do not produce significant immune rejection on post-transplantation; they are better suited for cell-based therapies. However, several critical issues need to be addressed to maximize stem cell-derived therapeutic effects. The key factor affecting the therapeutic application of stem cells is exposure to hostile conditions in vivo such as oxidative stress, which results in considerably low survival rate of these cells at transplanted sites, thereby reducing the therapeutic efficiency. Such limitation has led scientists to design clinically relevant, innovative and multifaceted solutions including the use of nanobiomaterials. Use of cytocompatible nanobiomaterials holds great promise and has gained attention of researchers, worldwide. Various nanobiomaterials are being explored to increase the survival efficiency and direct differentiation of stem cells to generate tissue-specific cells for biomedical research and futuristic therapies. These materials have superior cytocompatability, mechanical, electrical, optical, catalytic and magnetic properties. Non-invasive visualization of the biological system has been developed using magnetic nanoparticles and magnetic resonance imaging [MRI] approaches. Apart from viral vectors, non-viral carriers such as DNA nano carriers, single stranded RNA nanoparticles, liposomes and carbon nanotubes/wires are being exploited for gene delivery into stem cells. This article reviews potential application of various biocompatible nanomaterials in stem cell research and development.

Articular cartilage provides life-long weight-bearing and mechanical lubrication with extraordinary biomechanical performance and simple structure. However, articular cartilage is apparently vulnerable to multifactorial damage and insufficient to self-repair, isolated in articular capsule without nerves or blood vessels. Osteoarthritis (OA) is known as a degenerative articular cartilage deficiency progressively affecting large proportion of the world population, and restoration of hyaline cartilage is clinical challenge to repair articular cartilage lesion and recreate normal functionality over long period. Mesenchymal stem cells (MSC) are highly proliferative and multipotent somatic cells that are able to differentiate mesoderm-derived cells including chondrocytes and osteoblasts. Continuous endeavors in basic research and preclinical trial have achieved promising outcomes in cartilage regeneration using MSCs. This review focuses on rationale and technologies of MSC-based hyaline cartilage repair involving tissue engineering, 3D biomaterials and growth factors. By comparing conventional treatment and current research progress, we describe insights of advantage and challenge in translation and application of MSC-based chondrogenesis for OA treatment.

Stem and progenitor cell research is a complex and exciting field which promises curative discoveries in numerous areas including cancer, diabetes, and regenerative medicine. Use of biotic factors or growth factors has played an essential role in the development of stem cell research. These biologically active components have been administered into stem cells either to improve or maintain the stem cell proliferation, or to encourage controlled differentiation into more defined cell types. Small molecules such as 6-Bromoindirubin-3´-oxime (BIO), cardiogenol-C, etc can help stem cell research by controlling or influencing the regulatory changes in a controlled manner and to help understand the mechanisms during stem cell differentiation. Extra cellular matrix (ECM) is another significant biotic factor, which mediates cell and tissue behavior by influencing cell-matrix interactions. Thus, in this review we would like to emphasize significance of various growth factors in stem cell research.

Cell-based therapies, such as treatments with mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) are thought to have beneficial effects on the clinical outcome of orthopedic injuries, but very few animal studies with large sample size are published so far. Therefore, the aim of this study was to assess the safety and report the clinical outcome of allogenic, immature or chondrogenic induced MSCs in combination with PRP for the treatment of degenerative joint disease (DJD) in 165 horses. MSCs and PRP were isolated from a 6-year-old donor horse and transplanted either in their native state or after chondrogenic induction in combination with PRP into degenerated stifle (n=30), fetlock (n=58), pastern (n=34) and coffin (n=43) joints. Safety was assessed by means of clinical evaluation and the outcome was defined as failure to return to work (score 0), rehabilitation (score 1), return to work (score 2) and return to previous level (score 3), shortly (6 weeks) after treatment or at 18 weeks for the patients that returned for long-term follow-up (n=91). No adverse effects were noticed, except for three patients who showed a moderate flare reaction within one week after treatment of the fetlock joint without long-term effects (1.8% of 165 horses). Already after 6 weeks, 45% (native MSCs) and 60% (chondrogenic induced MSCs) of the treated patients returned to work (→ score 2+3) and the beneficial effects of the treatment further increased after 18 weeks (78% for native MSCs and 86% for chondrogenic induced MSCs). With the odds ratio of 1.47 for short-term and 1.24 for long-term, higher average scores (but statistically not significant) could be noticed using chondrogenic induced MSCs as compared to native MSCs. For all three lower limb joints a higher percentage of the treated patients returned to work after chondrogenic induced MSC treatment, whereas the opposite trend could be noticed for stifle joints. Nevertheless, more protracted follow-up data should confirm the sustainability of these joints.

Currently, pre-clinical and clinical studies have demonstrated the importance of stem cell based therapies for the treatment of human diseases. Fetal Mesenchymal Stem Cells (Fetal MSCs) are potential candidates that can be utilized for the treatment of different types of cancer. Recently, Wharton’s jelly (umbilical cord matrix) was proved to be a rich source of MSCs and they can be isolated by non-invasive methods such as Ficoll density gradient and antibodies coupled magnetic beads without any ethical issues. Documentation based on various literatures emphasized that fetal MSCs isolated from fetal umbilical cord possess beneficial activity in cancer therapy than adult MSCs. Specific markers of fetal MSCs such as tumor tropism (exhibit tumor microenvironments which act similar to anti inflammation immune cells) and low immunogenicity conferred them as a promising tool in gene therapy based oncology research. Based on these facts, this review summarizes the potential interaction of fetal mesenchymal stem cells with tumor cells and their use in clinical protocols.

Mesenchymal Stem Cells or Marrow Stromal Cells (MSCs) have long been viewed as a potent tool for regenerative cell therapy. MSCs are easily accessible from both healthy donor and patient tissue and expandable in vitro on a therapeutic scale without posing significant ethical or procedural problems. MSC based therapies have proven to be effective in preclinical studies for graft versus host disease, stroke, myocardial infarction, pulmonary fibrosis, autoimmune disorders and many other conditions and are currently undergoing clinical trials at a number of centers all over the world. MSCs are also being extensively researched as a therapeutic tool against neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Amyotrophic Lateral Sclerosis (ALS), Huntington’s disease (HD) and Multiple Sclerosis (MS). MSCs have been discussed with regard to two aspects in the context of neurodegenerative diseases: their ability to transdifferentiate into neural cells under specific conditions and their neuroprotective and immunomodulatory effects. When transplanted into the brain, MSCs produce neurotrophic and growth factors that protect and induce regeneration of damaged tissue. Additionally, MSCs have also been explored as gene delivery vehicles, for example being genetically engineered to over express glial-derived or brain-derived neurotrophic factor in the brain. Clinical trials involving MSCs are currently underway for MS, ALS, traumatic brain injuries, spinal cord injuries and stroke. In the present review, we explore the potential that MSCs hold with regard to the aforementioned neurodegenerative diseases and the current scenario with reference to the same.

Bone marrow transplant (BMT) is done by the replacement of damaged bone marrow with healthy one. These healthy bone marrow cells (BMCs) are usually collected from the crest of the Ilium in humans hence these cells are used to replace damaged ones in the treatment of bone marrow related diseases such as leukemia, aplastic anemia, congenital immunodeficiency and autoimmune diseases. Even though there are different methods, perfusion method is one of the simple, safe and less contaminated methods used to harvest BMCs and it can reduce the risk in allogenic BMT. Intra bone marrow – bone marrow transfer (IBM-BMT) is one of the best procedures for allogenic BMT. Due to enlisting of hematopoietic stem cells and mesenchymal stem cells, which are derived from donor, this method has distinguishable advantages in allogenic BMT. In this paper the perfusion method (for harvesting BMCs) and IBM-BMT (for their transplantation) have been critically reviewed and showed that both methods are together will become an effective combination in allogeneic BMT.

Introduction: In 1996, Goodell et al. first described a rare subpopulation of bone marrow stem cells termed the Side Population (SP). SP cells are known to be CD34 negative and to have a high repopulating capability. The SP was identified by ultraviolet excitation based on the efflux of the DNA binding dye, Hoechst 33342 (Ho342). ABCG2, a halftransporter that belongs to the ATP binding cassette transporter superfamily, is the major contributor to the SP phenotype by actively pumping Ho432 selectively from stem cells. To date, very little is known about the identification of the SP in peripheral blood samples, and about its peripheral circulation, enrichment or isolation to evaluate its therapeutic potential. Due to the SP potential role in tissue regeneration, we studied the numbers of the SP in bone marrow and peripheral blood samples in regard to count accuracy and reproducibility. Materials and methods: Bone marrow (BM) and apheresis (AP) specimens were obtained from healthy donors and patients undergoing stem cell transplantation. Bone marrow samples were obtained by aspiration. Peripheral blood cells after granulocyte colony stimulating factor (G-CSF) mobilization with or without chemotherapy, were obtained by apheresis. All samples were prepared for identification of SP cells by flow cytometry. Results: SP cells were detected in only 19 of 111 apheretic products, with relative frequency ranging from 0.01 to 4.75% of cells by the Ho342 exclusion method and flow cytometry analysis. Cell preparations used for these measurements consisted of 5 x 106 cells. However, no SP cells were detected when aliquots from the same positive specimens, consisting of previously stained 55 x 106 cells and fractionated into independent aliquots with 5 x 106 cells were used. Conclusions: In this study, we show that there is great variability in SP cell numbers when aliquots obtained either from leukapheresis or bone marrow products represent about 1% of the total product volume. In contrast, when aliquots represented about 12% of the total product volume SP cells measurements were consistent. The high cell number of some specimens can be a limitation for the accurate identification and isolation of the SP compartment. Aliquots containing a minimum of 55 × 106 cells should be used for statistical significance.