IRAP and PRP: Two New Weapons In The Arsenal To Treat Tendon and Joint Injuries In Horses

These two cutting-edge treatments are similar in certain ways, but very different in others.

By Michelle Delco, DVM Diplomate ACVS


Delco IRAP 1What is IRAP?

IRAP is a treatment that decreases inflammation and promotes healing.  Unlike traditional anti-inflammatory therapies like steroids or bute, IRAP is the horse’s natural anti-inflammatory – made by it’s own cells.   To understand what IRAP is and how it works, we must talk a bit about inflammation. When your horse sustains an injury, the damaged tissues release signals to the body that cause inflammation – you recognize inflammation as heat, swelling and pain.  One of the major signals for inflammation is a substance called IL-1.  Think of IL-1 as a “key” that turns on inflammation.  The “lock” that IL-1 fits into is called IL-1 receptor.  To prevent inflammation from getting out of control, the body has a natural blocker of inflammation called IL-1 receptor antagonist protein, or IRAP. 

Delco IRAP 2How does IRAP work?

So IRAP is a protein produced by your horse’s own cells to block inflammation.  Some very smart scientists figured out how to induce blood cells to increase the natural synthesis of these anti-inflammatory proteins.  The system involves harvesting about 60 mls of your horse’s blood and incubating it with special glass beads for 24 hours.  The blood cells produce large amounts of IRAP as well as other healing factors.  The IRAP-rich serum is then separated from the blood, harvested, frozen and stored for later use.   It can then be thawed and injected directly into a damaged or inflamed area (such as a joint) at any time.  Early studies and the experience of veterinarians who use IRAP suggests that it is an extremely useful tool to treat injuries in horses.  Again, because IRAP is derived from the horses’ own cells, we are able to avoid certain risks and negative effects of other “traditional” drugs.

What is PRP?Delco IRAP 3

Like IRAP, Platelet Rich Plasma or PRP is another product derived from your horse’s own blood.  PRP is loaded with natural healing proteins that accelerate tissue repair.  So what is a platelet? Platelets are the component of blood that cause clotting.  In addition to initiating clotting, platelets also act as factories and storage units for a myriad of growth and healing factors. When platelets are activated, they release these growth factors, which accelerate healing and improve the quality of healing.  The aim is not just fast healing, but good quality repair, so that your horse is less likely to re-injure.  

Unlike IRAP that requires 24 hours to process, PRP can be obtained in just a few minutes.  Your horse’s blood is again drawn, and spun in a centerfuge.  The process concentrates platelets into the plasma, and this platelet rich plasma is then separated from the rest of the blood.  The PRP can then be directly injected in to injured tissue, such as a tendon tear.  Often, this accomplished with ultrasound guidance.

Are one of these treatments right for your horse?  The first important step in answering this question is obtaining a diagnosis.  All injuries are not equal- they have different causes, different treatments and carry different prognoses.  To know what treatment is best, first a veterinarian specializing in lameness diagnosis needs to perform a thorough evaluation- likely to include an orthopedic examination, diagnostic analgesia (joint or nerve blocks) and imaging such as radiographs, ultrasound or MRI.   Once an accurate diagnosis has been made, your veterinary specialist can discuss the options and provide state of the art treatment options.  The goal is to get your equine athlete back to soundness as quickly as possible and keep them sound for the long haul.