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IRAP (Interleukin-1receptor Antagonist Protein) Therapy

This regenerative therapy has been used for decades in equine medicine for arthritic joints. Dr. Brown brought this therapy to Central Animal Hospitals and Tampa Bay K-9 Rehabilitation Center over 15 years ago to help dogs with painful joints due to arthritis.


 IRAP is made in our regenerative therapy lab by collecting a blood sample from the patient and placed in a special IRAP receptacle. This sample is processed through incubation over the next 24 hours where special white blood cells, called monocytes, adhere to the surfaces of the receptacle and the specially treated beads that are within. During this incubation process, these monocytes produce IRAP in the blood sample. After 24 hours, the blood sample is specifically processed to produce a rich Autologous Conditioned Serum (ACS). The sample generally renders between 8-14 mls of ACS. This is withdrawn and placed in individual sterile vials and frozen. Frozen ACS or IRAP rich serum may be stored for up to one year frozen. Injections into the affected joint occur three times over a six-week duration. Each treatment occurs two weeks apart and generally provides significant pain relief that is typically noticed after the second injection at two weeks. 


IRAP by definition is a protein that has an affinity for the surface receptors of Interleuken 1 commonly referred to as IL-1. Our bodies as well as animals’ have many interleukins which initiate different cascade processes. The IL-1 cascade is responsible for inflammation which results in pain in most cases. Chronic inflammation degrades cartilage within the joint and attracts mineralization or arthritis. When IRAP attaches to IL-1 surface protein receptors within the joint, there is a blockade effect which in turn, doesn’t allow the cytokine production that results in inflammation and pain in that joint. Since the IRAP is injected into the affected joint, the resultant anti-inflammatory, anti-pain effect is localized to the tissues in that joint. In Dr. Brown’s experience, if the only pain being experienced by the pet is from a specific joint, after the three treatments, many pets discontinue their pain medications. This pain blockade can last up to a full year. 


Elbow dysplasia is a nagging condition that can rarely be managed well with pain medication alone. In older dogs, many have fragments of bone from the medial coronoid process referred to as FCP or fractured coronoid process. Surgical removal of these fragments in older dogs rarely improves the pain. Off-loading the medial compartment via PAUL surgery is extremely painful and has variable results. Dr. Brown was very frustrated with this condition over the years and the poor response to surgery and medical management and looked to the horse racing industry to see how they were managing similar injuries. That was when IRAP was introduced to him. Many dogs have experienced excellent results from this non-invasive, non-surgical treatment. 


The stifle, or knee, is the most common joint injury in a dog. Dogs that have experienced cruciate injury or instability typically need surgery to have the best outcome. Many dogs have had cruciate injuries at a young age but did not have corrective surgery. Over time, arthritis has developed rendering the pet a poor candidate for surgery. These dogs are excellent candidates for IRAP. To be clear, IRAP is not an option for cruciate injury in lieu of surgery during the initial injury phase. Surgery is the best option. 


Dogs who have experienced shoulder injuries and have either had surgery or not, often develop chronic inflammation in the joint. Many injuries involve primary muscle tendons that make up the shoulder apparatus. In some cases, surgical correction may be the best option for the patient, but once treatment options are exhausted, IRAP is an excellent therapy to help alleviate pain. Again, surgery may be the best option initially, but once considerable morbidity has developed, IRAP may be very helpful. 


Dogs with hip dysplasia have variable issues. Dogs are typically born with this condition and over time, secondary arthritis develops due to the the incongruity of the joint surfaces. Muscles, tendons, and tissue sheaths tighten which only worsen the condition. Surgical correction is often the best long-term solution for these cases, but many times, age or other factors make surgery less desirable. IRAP “may” help these cases with joint pain, but will not have any effect on the other issues that could be adding to the pain score. Assessment of these pets via a rehabilitation exam and medical record/X-ray review will help determine if IRAP may be beneficial. 

Currently, the spine is not treated with IRAP at our hospital. 

Since IRAP is an autologous serum (derived from the patient), it can be repeated as needed with virtually no risk of developing antibodies against it. When biologicals are injected into patients that are not autologous, the body’s natural response is antibody production. With time, this would render the treatment ineffective. 

Interleuken therapy is an exciting area of regenerative medicine. There is much to come on the horizon in regard to the treatment of conditions in both veterinary medicine and human medicine.