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Research has shown as much as 500 to 1000 times as many mesenchymal and stromal vascular stem-like cells exist in adipose as compared to bone marrow.77-79 For further information on ongoing stem cell research, go to todaysveterinarypractice.com. STEM CELL HARVESTING & ADMINISTRATION The ability of AD-SCs to support and serve as a cell reservoir for connective tissue and joint repair is the basic theory for their use in joint regenerative medicine. Autologous AD-SC therapy involves: 1. Harvesting fat from the available sites 2. Isolating the stem and regenerative cells 3. Administering the cells back to the patient. In veterinary practice, these cells are typically found in the adipose deposits near the tail (horses) and from the ventral fat pad (dogs). In these cases, fat is either lipoaspirated80 or, if taken surgically, en bloc, morselized to permit separation of the stem– stromal elements within the adipose complex. After preparation, this tissue, combined with HDPRP, can then be injected during open surgical intervention or by guided injection. It is important to understand that undifferentiated stem/stromal cells must adhere to other cells (cell-to-cell contact) or to extracellular matrix/perivascular tissues in order to proliferate effectively. Within an injured or degenerative site, the stem/ stromal cell fate is controlled by a complex set of physical (cell-to-cell) and chemical signals (paracrine-autocrine effects) dictated by the cellular and chemical microenvironment (niche).81 Further, these cells are believed to proliferate and differentiate from signaling based on the environment in which they are placed. Therefore, if AD-SCs are placed within and adherent to damaged connective tissue, uncommitted progenitor and stem/stromal elements within the AD-SC graft are activated and differentiate toward the specific connective tissue lineages for growth and repair. CONCLUSION Stem cell therapy in regenerative veterinary medicine is a viable option for the equine as well as the small animal veterinarian, offering a safe and clinically effective tool for the clinician to assist in his/ her treatment of the animal with difficult wounds or unresolved musculoskeletal or joint pain. n AD-SC = adipose-derived stem/stromal cell; HDPRP = high-density platelet-rich plasma Techno logy for Stem Cell & Plasma Con centrate Harvesting Stem Cell Harvesting Currently, 2 companies provide stem cell technology for veterinary medicine. Vet-Stem (vet-stem.com), the first company to commercially offer stem cell use, provides a practical “as needed” approach: Veterinarians can remove fat from an animal and ship it overnight to the Vet-Stem laboratory. There, the fat sample is processed by chemical digestion, isolation, and concentration, then returned to the veterinarian for injection into the animal’s injury site. MediVet America (medivet-america.com) offers the ability to do stem cell procedures at point of care, within clinical surgical facilities. Both companies have reported favorable results in their treatment protocols and reported case studies.1,2 Plasma Concentrate Harvesting Various portable commercial centrifugation units exist that process blood samples, resulting in platelet-rich plasma concentrates. The one used for our investigation was the patented Harvest Technologies (harvesttech.com) Smart PReP2 centrifugation system: This system uses a sterilized blood collection kit that allows in-office phlebotomy and processing in a tabletop bidirectional centrifugation unit.3 It is capable of consistently concentrating 4 to 5 times, or more, the patient’s circulating level of platelets, achieving the needed therapeutic level of HDPRP. References 1. Vet Stem case studies: vet-stem.com/equine/casestudies.php, vet-stem.com/ smallanimal/casestudies.php 2. MediVet America case studies: medivet-america.com/casestudies.html 3. Harvest Technologies product information: harvesttechnologies.com/products/ smartprepmain.html Go to TodaysVeterinaryPractice.com for further information on how adipose-derived stem cells were originally introduced for use in medicine as well as details regarding current research taking place. | Advances in Stem Cell Therapy 28 Today’s Veterinary Practice July/August 2011 In the early 1990s, adult mesenchymal stem cells were discovered to have an active role in connective tissue repair.1 These cells were first labeled as mesenchymal stem cells (MSCs)2 because of the ability to differentiate to lineages of mesenchymal tissue, and were recognized to be an essential component of the tissue repair process.3 An interesting observation made about MSCs was the ability to “home in” and help repair areas of tissue injury using chemotactic mechanisms.1 While bone marrow has historically been used as a source of MSCs, adipose-derived stromal elements were shown to have nearly identical fibroblast-like morphology and colonization, immunophenotypic capabilities, successful rate of isolation, and differentiation capabilities.4-6 The healing potentials of the very heterogenic, adipose-derived stem/stromal cells (AD-SCs) were demonstrated in early clinical use for cranial defect and chronic fistula repair, without side effects.7,8 MSCs, along with other cells within the adipose stroma (together making up AD-SCs), react to cellular and chemical signals, and have been shown to differentiate and assist in
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