Regenerative medicine is one of the fastest growing areas of research and development in veterinary medicine for the treatment of osteoarthritis, and if you have a dog who is suffering from arthritis or joint pain, then you need to know about it! Because PRP and stem cell therapy are both still relatively new in the veterinary marketplace and require some specialized training, not all veterinarians are aware of these therapies or trained to utilize them. Big Barker’s consulting vet, Dr. Sarah Wooten, had a chat with David Dycus, DVM, MS, DACVS-SA to learn more about these therapies.
PRP is platelet-rich plasma sourced from your own dog’s blood. A veterinary technician draws blood and spins it down in a special centrifuge, separating out platelet-rich plasma, which is then injected back into the affected joint. PRP contains an abundance of growth factors, which are the compounds in the body that stimulate cells to start healing. When PRP is injected into a damaged joint, tendon, or ligament, cells in the injured tissue are stimulated to heal faster.
Stem cell therapy is sourced from your own dog’s fat cells. Following sedation, fat cells are harvested from your dog’s body and sent to a laboratory, where stem cells are grown from the fatty tissue. The stem cells are then shipped back to your veterinarian’s office, and then injected into injured ligaments, muscles, joints, or tendons. The idea is that the stem cells promote healing and growth of healthy tissue at a faster rate, helping your dog to heal faster.
Dr. Sarah Wooten: PRP and stem cell therapy: Why should clients be considering these regenerative therapies for their dogs?
Dr. David Dycus: Regenerative medicine in orthopedics is used for osteoarthritis management and orthopedic soft tissue injuries. The goal is not to replace or grow new tissue but rather take a high concentration of growth factors and anti-inflammatories to an area of otherwise poor healing. It is suspected that regenerative medicine can initiate resident cells to up-regulate and facilitate a better healing response.
SW: How best is PRP and stem cell therapy used to help dogs?
DD: To get the best response from regenerative medicine, your dog needs a diagnosis of arthritis, and you must be willing to treat the underlying condition. It’s not a magic silver bullet that is going to replace conventional medicine. Regenerative medicine augments other therapies. Therefore, combination therapy is key when considering regenerative medicine such as medical and surgical intervention, incorporation of regenerative medicine, and rehabilitation therapy.
SW: What are the pros and cons of stem cell therapy? Any new studies out there that I should know about?
DD: The original thought of stem cell therapy was simply just to replace lost tissue and the stem cells would regenerate new tissue. However, research has shown that the #1 mechanism of repair is the release of trophic factors. These trophic factors in the form of cytokines and chemokines release different growth factors and also provide an anti-inflammatory environment as well as help with immune system modulation. The trophic support provided from MSC helps to diminish tissue injury, promote neovascularization, recruit and induce proliferation of resident stem cells, inhibit fibrosis, and act as a carrier for therapeutic genes. In terms of cons, it would really be the cost at this point in time as there are really no side effects that can result from it. The one downside would be that it may not be effective in all cases; however, I think when used appropriately, then it is likely to be effective.
There are tons and tons of new papers coming out in the human field using animal models. Two new ones would be from Sherman Canapp on using stem cell/PRP for shoulder injuries and for partial CCL injuries.
For us, we never use stem cells alone; it is always in combination with PRP as we found that PRP alone works well, stem cells alone work well, but stem cell/PRP tends to work better together.
SW: What are the pros and cons of PRP?
DD: Essentially PRP is blood plasma concentrated with platelets. Within these platelets, there are huge reservoirs of bioactive proteins and growth factors. These proteins have been shown to initiate and/or accelerate tendon, ligament, and cartilage repair. It has been stated that it can induce some regeneration, but I would be very cautious about using this statement. Primarily PRP is great in decreasing inflammatory mediators especially in osteoarthritis (OA) along with initiating reparative cytokines. Furthermore, they reduce pain and improve articular function in OA.
Within PRP we are primarily interested in the growth factors found in the alpha granules of the platelets such as transforming growth factor β (TGF-β), platelet derived growth factor (PDGF), insulin-like growth factor (IGF-1), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and fibroblast growth factor (FGF).
So why should we care about these growth factors? The answer is simple in that knowing what is contained in the granules and what growth factors are involved help understand the healing properties of PRP. For example VEGF and FGF promote blood vessel growth while PDGF, FGF, and TGF-β enhance cellular proliferation. Lastly, TGF-β and IGF-1 promote extracellular matrix formation, which is especially important in OA. The primary roles and functions of PRP are to enhance recruitment, proliferation, and differentiation of cells associated with tissue healing and regeneration. Furthermore, it provides fibrin to serve as a matrix and scaffold, building blocks of healing.
SW: What should dog owners be asking their regular providers about regenerative medicine therapies?
DD: Make sure to ask your veterinarian if the product/machine they are using has been validated for dogs. Not all companies are created equal, and what makes things more complicated is that we still are not entirely sure what we want in a product, how often should we inject, do we want white blood cells or not (likely depends on the condition and severity of the condition being treated)? Owners should also make sure that their vet is comfortable with intra-articular injections and ultrasound guided injections into the injured tissue, as injecting intravenously is likely not effective.
SW: What is the next great thing in regenerative medicine?
DD: Allogeneic stem cell therapy would be the holy grail for stem cell usage. It is where the tissue is harvested from a donor, the cells are isolated and expanded, and then the cells are returned to a different patient. When stem cells are cultured it changes the cell markers and effectively disables the immune response; therefore, rejection by the recipient is not expected. The thought of allogeneic stem cells allows for more rapid use because they will be available for use “off the shelf”. Also, some individuals produce more and better stem cells (their cells are more predictable and consistent). Furthermore, as we age, so do our stem cells, so having younger individuals available is ideal. This is an area that is going to be looked at very soon and clinical trials are beginning. It is currently available in Australia.
Dr. Sarah Wooten is Big Barker’s consulting veterinarian. Dr. Wooten is a small animal veterinarian with more than 15 years of clinical experience. She is an expert contributor to sites such as vetstreet.com, DVM360.com, and The Bark Magazine.