Clean Run - September 2012 - 54

and time resources necessary to go through the FDA-licensing process. There is a growing body of scientific evidence to support that the age of the donor affects not only the function of the cells but also the number of cells that can be harvested. Younger is better! This paired with the convenience of “off the shelf ” mesenchymal stem cells have made the future use of allogeneic mesenchymal stem cells interesting to veterinary clinicians. To date, there is not a licensed allogeneic mesenchymal stem cell product available for dogs or horses. Clinical trials utilizing allogeneic MSCs are the only legal way to access this therapy. For this reason, most veterinary stem cell procedures involve autologous cells recovered from the patient’s own body.

blood cells to minimize the possibility of an immune reaction. Platelet therapy can usually be provided for under $700 making it a reasonable addition to most treatment protocols. Because cost and availability make this treatment option a reasonable one for most patients, the platelet has become a “workhorse” in regenerative therapies centering around muscle, tendon, ligament, and joint injury.

Interleukin-1 Receptor Antagonist Protein
Interleukin-1 receptor antagonist protein (IRAP-1) has also been utilized particularly in the equine patient to treat inflammation. This cytokine or natural chemical is released by monocytes, a type of white blood cell, and is known to be capable of decreasing inflammation. IRAP is collected by first drawing whole blood and then culturing it for 24 hours. Many of these products are created by activating the monocytes in the whole blood with glass beads. After 24 hours, the whole blood is centrifuged. The plasma phase is collected and the IRAP within the plasma can be used intralesionally to decrease inflammation. Joints have been the sites of this therapy most often. This product can be stored frozen for use up to 5 years from collection. Cost for this therapy is usually $300-500.

Platelets
The use of the platelet either in platelet rich plasma, platelet concentrate, or platelet lysate has gained in popularity particularly in equine medicine. For regenerative medicine, the platelets may be either fresh or frozen. Most people understand the platelet as a part of whole blood necessary for primary clotting. The platelet appears to have the unique ability to provide growth factors such as PDGF (platelet derived growth factor), TGF-B (transforming growth factor-beta) and VEGF (vascular endothelial growth factor) to an injured area. Platelets act as messengers and orchestrate a healing matrix in the tissue. The healing action of the platelet is actually to call mesenchymal stem cells in the body to an area of concern. There are a number of placebocontrolled studies in horses, goats, and dogs that support the use of platelets in tendon and ligament injury. Platelets have also been used topically for large wound healing particularly in areas where skin grafts are not available. Platelet therapy has the advantage of being readily available and easy to provide without substantial upgrades in the average veterinary laboratory. Standard preparations of platelet rich plasmas have been documented in the dog through transfusion practice for over 50 years. Early pilot trials indicate that it is important that the platelets selected for therapeutic use have not been exposed to nonsteroidal anti-inflammatory drugs or platelet inhibitors. Exposure to these drugs makes the platelets less capable of participating in the healing process. This can limit the use of recipient’s own cells if the injury has been treated with these systemic drugs. Like transfusion, it is important when using platelets for this type of therapy that the cells be separated from red blood cells and white

Which Cellular Therapy?
How do you decide if the new cellular therapies, autologous or allogeneic, are going to help your dog? Placebo controlled studies give us the best comparison of the use of cellular products with more traditional therapies. There are a number of multi-institutional studies that have evaluated the use of intralesional cell therapy for osteoarthritis in multiple and single joint applications. Results of these studies support the use of platelets and MSCs for connective tissue injury and osteoarthritis. A growing number of case reports and small number studies for many of these applications are now appearing in the veterinary literature. This is a start towards documenting the scientific basis for use of these cells. Time will tell what role regenerative medicine will play for the canine athlete. Until the scientific evidence is available, make sure that you know what cellular product is used, how it was prepared, and how many treatments are needed for the desired effect. Platelets, hematopoietic stem cells, mesenchymal stem cells, and IRAP when used properly should offer new solutions to old problems. D

Dr Hale is a nationally recognized expert in veterinary transfusion medicine and regenerative medicine with over 20 years experience. She is a member of the regulatory committee for the North American Veterinary Regenerative Medicine Association. Currently, Dr. Hale is in private referral practice limited to critical care and regenerative medicine. She can be reached at the Ann Arbor Animal Hospital, Ann Arbor, Michigan, (734) 662-4474 or via email at drhale@annarboranimalhospital.com. 54 Clean Run | September 12

Clean Run - September 2012

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