Regenerative Medicine – What Can We Learn from Our Equine Surgeon Colleagues?

Autologous conditioned serum (IRAP)
Autologous conditioned serum (ACS) is an example of an available treatment that may become more targeted in the future when clearer indications are developed. It uses the idea of specific inhibition of deleterious cytokines and mediators using anti-inflammatories inflammatory substances produced by the animal’s own blood cells. Extrapolation from the human data, and recently published equine data (Frisbie et al. 2007), suggests that there would be up-regulation of IL-1 receptor antagonist, IL-4, IL-10, fibroblast growth factor and transforming growth factor- in such serum. Specifically, IRAP, a substance that inhibits IL-1 activity, decreases the progression of joint disease and is believed to be present in high amounts in ACS.

Controlled data on the efficacy of ACS in clinical cases are currently lacking in the horse, although in the CSU OA model, treated horses showed a significant improvement in lameness and improvement in some parameters of articular morphology (Frisbie et al. 2007).

The original indication for the use of ACS was degenerative joint disease that failed to respond to intra- articular corticosteroids. However, clinical impressions in horses with chronic lameness have been disappointing. Therefore ACS is used predominantly in cases of mild synovitis and early OA, particularly in patients where corticosteroids may be contraindicated. For example, ACS is commonly used as a ‘maintenance’ injection in mild lameness and performance problems in competition horses. Horses successfully treated with IRAP that return to competition often receive prophylactic treatment before, after or during competitions. Therefore, it is preferable to recover and store additional doses for later use in these patients.  [...]