First of all, we are not talking about embryonic stem cells here, but adult-origin stem cells that are taken from the same patient that will be treated with them. Stem cells are present in every tissue of an adult animal’s body. These cells use blood vessels to travel to injured areas where they can differentiate directly into the type of cell needed and/or stimulate and recruit other cells in the area to do so. Their presence in a tissue also helps block pain through a mechanism similar morphine’s mechanism of action, down regulates inflammation, blocks cell death, stimulates the creation of new blood cells, and blocks the formation of or resolves scar tissue.
Stem cell therapy seems most effective when tissue damage is being caused by inflammation and/or a lack of adequate blood supply. Research abounds into exactly which conditions may be amenable to treatment, but right know orthopedic diseases like osteoarthritis, tendon and ligament injuries, and fractures top the list of current uses in veterinary medicine. In the not too distant future, treatment for laminitis in horses; some types of liver, heart, and kidney disease; and immune-mediated diseases (e.g., inflammatory bowel disease and atopic dermatitis) may also be commercially available. In fact, some doctors and stem cell processers are currently involved in research protocols and the "compassionate use" of these therapeutic options right now.
The exact details regarding how the service is provided depends on the veterinarian and other service providers involved. Generally, the doctor will collect tissue (fat or bone marrow) from the animal under local or general anesthesia; the tissue is processed to isolate, replicate, and concentrate the stem cells; and the stem cell solution is either injected directly into the injured area (e.g., a joint) and/or given intravenously. Treatment can be repeated more than once if the benefits start to wear off over a period of time.
Determining whether or not stem cell therapy is a reasonable option for a particular individual is very important. Like any type of medical therapy, to be most effective it should be based on an accurate diagnosis, a reasonable expectation as to what the best, worst, and most likely outcomes could be, and dedication to treating the animal as a whole (e.g., surgery to repair a fully ruptured ligament followed stem cell therapy and physical rehabilitation). Stem cells are not magical cure-alls, but they are invaluable for some pets.
Dr. Jennifer Coates
Stem Cell 101: Principles of Regenerative Medicine. Robert Harman DVM, MPVM. Wild West Veterinary Conference. Reno, NV. October 17-20, 2012.