Helping Cultured Stem Cells Roll

Sources of stem cells
Veterinary applications of stem cell therapy as a means of tissue regeneration have been largely shaped by research that began with the use of adult-derived mesenchymal stem cells to treat animals with injuries or defects affecting bone, cartilage, ligaments and/or tendons.[62][63][64] There are two main categories of stem cells used for treatments: allogeneic stem cells derived from a genetically different donor within the same species[65][60] and autologous mesenchymal stem cells, derived from the patient prior to use in various treatments.[58] A third category, xenogenic stem cells, or stem cells derived from different species, are used primarily for research purposes, especially for human treatments.[66]
Most stem cells intended for regenerative therapy are generally isolated either from the patient’s bone marrow or from adipose tissue.[60][59] Mesenchymal stem cells can differentiate into the cells that make up bone, cartilage, tendons, and ligaments, as well as muscle, neural and other progenitor tissues, they have been the main type of stem cells studied in the treatment of diseases affecting these tissues.[63][67] The number of stem cells transplanted into damaged tissue may alter efficacy of treatment. Accordingly, stem cells derived from bone marrow aspirates, for instance, are cultured in specialized laboratories for expansion to millions of cells.[60][59] Although adipose-derived tissue also requires processing prior to use, the culturing methodology for adipose-derived stem cells is not as extensive as that for bone marrow-derived cells.[68][69] While it is thought that bone-marrow derived stem cells are preferred for bone, cartilage, ligament, and tendon repair, others believe that the less challenging collection techniques and the multi-cellular microenvironment already present in adipose-derived stem cell fractions make the latter the preferred source for autologous transplantation.[58]
New sources of mesenchymal stem cells are currently being researched, including stem cells present in the skin and dermis which are of interest because of the ease at which they can be harvested with minimal risk to the animal.[70] Hematopoetic stem cells have also been discovered to be travelling in the blood stream and possess equal differentiating ability as other mesenchymal stem cells, again with a very non-invasive harvesting technique.[71]
There has been more recent interest in the use of extra embryonic mesenchymal stem cells. Research is currently underway to examine the differentiating capabilities of stem cells found in the umbilical cord, yolk sac and placenta of different animals. These stem cells are thought to have more differentiating ability than their adult counterparts, including the ability to more readily form tissues of endodermal and ectodermal origin. [61]
[edit]Stem cells and Soft Tissue Repair
Because of the general positive healing capabilities of stem cells, they have gained interest for the treatment of cutaneous wounds. This is important interest for those with reduced healing capabilities, like diabetics and those undergoing chemotherapy. In one trial, stem cells were isolated from the Wharton’s jelly of the umbilical cord. These cells were injected directly into the wounds. Within a week, full re-epithelialization of the wounds had occurred, compared to minor re-epithelialization in the control wounds. This also showed the capabilities of mesenchymal stem cells in the repair of epidermal tissues.[72]
Soft palate defects in horses are caused by a failure of the embryo to fully close at the midline during embryogenesis. These are often not found until after they have become worse because of the difficulty in visualizing the entire soft palate. This lack of visualization is thought to also contribute to the low success rate in surgical intervention to repair the defect. As a result, the horse often has to be euthanized. Recently, the use of mesenchymal stem cells has been added to the conventional treatments. After the surgeon has sutured the palate closed, autologous mesenchymal cells are injected into the soft palate. The stem cells were found to be integrated into the healing tissue especially along the border with the old tissue. There was also a large reduction in the number of inflammatory cells present, which is thought to aid in the healing process.