Current Stem Cell Research & Therapy - Volume 7, Issue 5, 2012

Introduction: Osteoarthritis (OA) represents an increasing health issue worldwide. Regenerative medicine (RM) has raised the hope for introducing revolutionary therapies in clinical practice. Detection of autologus cell sources can improve accessibility to RM strategies. Objectives: To assess the presence and biological potential of mesehchymal stem cells in three tissues (subchondral bone, synovial layer, periarticular adipose tissue) in late stages osteoarthritic patients. Material and Methods: Samples were collected from subjects undergoing total knee replacement (TKR). MSCs were isolated and cultured in complete αMEM with β FGF. Cell morphology and growth potential was assessed. Flow cytometry was used for detection of several relevant cell surface markers. Quantitative and qualitative assessment of differentiation potential towards three mesenchymal lineages (osteogenesis adipogenesis chondrogenesis) was performed. Time lapse life cell imaging of nondiferentiated cells over 24 hours period was used to determine cell kinetics. Results: Mesenchymal cells derived from all donors and tissue types showed morphology, growth and surface cell markers associated with stemness. All cell types underwent differentiation toward three mesenchymal lineages with significant differences between tissues of origin, not between donors. Cell kinetics, as derived from life imaging records, was variable with tissue of origin, significant higher for adipose derived MSCS. Conclusion: Human late stage OA mesenchymal tissues, contain progenitors with proliferative and differentiation potential of MSCs. These populations can be used for research and autologus regenerative therapies. Further comparative studies with age matched non OA samples has the potential of contributing to deepening knowledge about disease occurrence and progression.

Background: Stem cell culture for regenerative medicine needs platelet rich plasma (PRP) as fetal bovine/calf serum (FBS/FCS) substitute. However, the various studies used various protocols in preparing and processing the PRP. This study aimed to compare and conclude the most effective and efficient protocol. Methods: we searched in vitro studies that used human PRP as FBS/FCS substitute to culture human cells, and compared the various available protocols to identify the easiest and effective protocols for the preparation of PRP and the release of the growth factors (GFs) to support the highest cell growth in stem cell culture. Results: ten studies fulfilled the selection criteria and were included in the analysis. Discussion: Almost all studies on bone marrow mesenchymal stem cell (BM-MSC) and adipose stem cell (AT-SC) showed that platelet lysate and/or activated platelet releasate were superior or at least the same as either FBS or FCS, except for one study that got different results on human AT-SC. Several studies showed that either 5% activated PRP (aPRP) or platelet lysate (PL) was sufficient to support cell growth, or even better when they were compared to 10% FBS, while higher concentrations were counterproductive. However, some studies showed that 10% aPRP or PL was needed. The difference between studies was due to the difference in either the PRP preparation from blood and in the PRP processing to release the GFs, which yield various GF concentrations. Conclusion: In conclusion, studies are needed to reveal the optimal final platelet counts for the various PRP processing methods for various kinds of cells. The easiest PRP processing is freezing to -20°C followed by thawing, or thrombin activation using a final concentration of 100U/mL.

A growing array of synthetic bone regeneration scaffolds has been in use over the last century. These scaffolds aim to provide a three dimensional substrate for bone cells to populate on and to function appropriately. The majority of commercially-available scaffolds are based on calcium sulphate salts, calcium phosphate salts, or composites of the two. The mechanical and biological properties of these scaffolds are a result of the properties of the constituent materials and their ratio in the composite. This review addresses the mechanical and biological characteristics and provides an up-to-date summary of the clinical data available about the use of these calcium-based scaffolds. It will also assess the benefit of using stem cell technology along with this type of scaffolds. This article links between the basic science evidence and the clinical outcomes and details the commercially-available options.

Tissue engineering approaches for promoting the repair of peripheral nerve injuries have focused on cell-based therapies involving Adipose-derived stem cells (ASCs). The authors evaluated the effects of undifferentiated ASCs and of neurally differentiated ASCs on the regenerating abilities of peripheral nerves. We hope that this would demonstrate the feasibility of using adipose derived stem cells for peripheral nerve regeneration and provide clues regarding the use of adipose- derived stem cells. ASCs were isolated and cultured. Then the cells were cultured with neuronal induction agents for neural differentiation. ASCs and neurally differentiated ASCs were transplanted into sciatic nerve defects. After 12 weeks, the number and diameter of the myelinated fibers were measured and nerve conduction study was done. The extent of regeneration of myelinated fibers in the neurally differentiated ASCs transplanted group was greater than that in the ASCs transplanted group or the control group. However, thickness of myelin sheath and diameter of nerve fibers in the ASCs transplanted group were greater than those in the neutrally differentiated ASCs transplanted group or the control group. Nerve conduction study showed good recovery in the neurally differentiated ASCs transplanted groups. Muscles can atrophy and contract if denervation has started. It would be difficult to recover muscle function even if the nerve was reinnervated. Therefore, although neurally differentiated ASCs were found to have a greater functional effect than non-differentiated ASCs, time constraint is important when considering a method of ASCs transplantation.

The usefulness of adult stem cells in research and therapeutic applications highly relies on their genomic integrity and stability. Many laboratories including ours have addressed this concern using methods such as karyotyping, Qbanding, fluorescent in situ hybridization, array CGH, flow cytometry and Pap test to evaluate number and structure of chromosomes and cellular phenotype. This review attempts to summarize the findings reported so far for the studies on chromosomal aberrations in adult stem cells and warrant to perform certain basic tests before transplantation to avoid any adverse reactions, which will thus aid in better therapeutic output after cellular transplantation in the treatment of various diseases.

Spinal cord injury is a devastating, traumatic event, and experienced mainly among young people. Until the modern era, spinal cord injury was so rapidly fatal that no seriously injured persons would survive long enough for regeneration to occur. Treatment of spinal cord injury can be summarized as follows: prevent further cord injury, maintain blood flow, relieve spinal cord compression, and provide secure vertebral stabilization so as to allow mobilization and rehabilitation, none of which achieves functional recovery. Previous studies have focused on analyzing the pathogenesis of secondary injury that extends from the injury epicenter to the periphery, as well as the tissue damage and neural cell death associated with secondary injury. Now, there are hundreds of current experimental and clinical regenerative treatment studies. One of the most popular treatment method is cell transplantation in injured spinal cord. For this purpose bone marrow stromal cells, mononuclear stem cells, mesenchymal stem cells, embryonic stem cells, neural stem cells, and olfactory ensheathing cells can be used. As a result, cell transplantation has become a promising therapeutic option for spinal cord injury patients. In this paper we discuss the effectiveness of stem cell therapy in spinal cord injury.

Mesenchymal stem cells (also known as multipotent stromal cells, MSCs) are considered as promising candidate cells for stem cell-based therapy. However, the applications of MSCs are facing controversial concerns of potential tumorigenic risks. There is also increasing evidence that MSCs may play a modulatory role in the development and progression of tumors. MSCs have the potential to migrate to tumor sites and promote tumor cell proliferation, invasion and metastasis. In addition to these risks, MSCs also have shown to be an attractive target for gene/cell-mediated anti-tumor therapy. These complicated behaviors of MSCs in cancer warrant further study to evaluate the benefits of MSCs treatment and the long-term risk of tumor origin or incidence from MSCs under different pathological conditions.

Allogeneic hematopoietic stem cell transplantation (HSCT) use has expanded markedly to treat different disorders like hematologic malignancies, immunodeficiency, and inborn errors of metabolism. However, it is commonly associated with complications that limit the benefit of this therapy. Acute renal failure occurs commonly after HSCT and results in increased risk of mortality. In many instances, children post-HSCT develop acute renal insufficiency in the context of other organ failure, necessitating intensive care unit admission for management. Recently, continuous renal replacement therapy (CRRT) has emerged as the favored modality of renal replacement therapy in the care of critically ill children who are hemodynamically unstable. Currently, CRRT is being utilized more often in the care of critically ill post- HSCT children to treat renal failure or to prevent fluid overload (FO). FO>20% has been shown in many studies to be an independent risk of mortality in critically ill children and therefore, many clinicians will initiate this therapy due to FO even without overt renal failure. CRRT may be beneficial in disease processes as acute lung injury due to removal of fluid. CRRT results in improved oxygenation in post-HSCT children with acute lung injury and this improvement is sustained for at least 48 hours after initiation of this therapy. Survival in post-HSCT children requiring this therapy ranges from 17% to 45%, however, long term survival is still poor. This review will discuss current practice of CRRT in children post-HSCT, as well as future directions.