As a lameness specialty practice, we treat lameness due to arthritis more than any other pathology. There are many therapeutic options available today including the gold standard - intra-articular steroids with hyaluronic acid - and other supplemental treatments such as shock wave therapy, systemic injectables such as Legend and Adequan, and oral nutraceutical products such as glucosamine, chondroitin sulphate, and hyaluronic acid. Even with this arsenal of therapeutics, we still sometimes find osteoarthritis a frustrating management issue. Recently, a new therapeutic option has become available which involves gene therapy. The technique is called IRAP - or Interleukin-1 Receptor Antagonist Protein. In order to understand how IRAP therapy works, it is necessary to understand the basics of osteoarthritis and joint pathology.
What causes osteoarthritis?
Osteoarthritis can occur for a variety of reasons, including acute trauma, joint sepsis and soft tissue injury; however it is most commonly caused by some initial insult to a joint followed by daily wear and tear from performance use. Regardless of the cause, a cycle of events continues the inflammatory process, resulting in continual degradation of the cartilage matrix. Until now, the goal in managing osteoarthritis has been breaking this cycle of inflammation with the use of steroids and hyaluronic acid. While steroids can be very successful in reducing inflammation in a joint and thus slowing the degradation of cartilage, it is a short-term fix and they do little to protect actual joint tissues.
What does the procedure involve?
Blood is drawn aseptically from the horse into a syringe containing prepared beads that induce an inflammatory response while being incubated for 24 hours. The blood is then spun and separated, and the serum which contains these anti-inflammatory proteins is put into individual dose syringes which can then be frozen for future use. The intra-articular treatments are administered every 7 to 10 days for three treatments. Results are typically seen by the second treatment. IRAP can also be used as maintenance therapy throughout a competition season to reduce the amount of steroid use. IRAP therapy is not for every horse. There are some factors that make a horse a less successful candidate; however the therapy shows great promise for horses that have become refractory to traditional management of osteoarthritis. Ask if your horse is a candidate for IRAP therapy at your next appointment!