Equine sports medicine has the reputation of being, in some cases, cutting edge. This makes equine veterinary medicine both exciting and challenging to keep up with. One of the neatest new therapies on the scene that has been gaining popularity over the last decade is a field called regenerative medicine. Here are the highlights.


A very common range of injuries seen in equine athletes include tendon and ligament tears and strains, not unlike what human athletes deal with. These types of injuries can be challenging to fix because the connective tissue that surrounds joints and connects bone to bone and bone to other structures does not have fantastic blood supply and once damaged, never heals back to its original strength. The concept of regenerative medicine is to employ certain types of cells and cellular products to heal these tissues close to their original strength.


The three most common types of regenerative medicine therapies are stem cells, platelet-rich plasma (PRP), and interleukin-1 receptor antagonist protein (IRAP). Although they all work in different ways, each therapy can help with connective tissue healing. Let’s look at each type in a little greater detail.


Stem Cell Regenerative Therapy


Stem cells are undifferentiated cells in the body that can develop into another cell type. For use in equine therapy, stem cells from an injured horse are taken via a sample of the horse’s own bone marrow or fat. These cells are then modified in a laboratory and then re-injected back into the same horse, either directly into the injured area or into the bloodstream.


When these stem cells enter the injured area, they can help decrease inflammation. While initial inflammation in an acute injury is necessary for the body to begin its own healing process, prolonged inflammation has detrimental effects on the tissue. Additionally, stem cells can help “organize” the growth of new connective tissue. One of the problems with healing tendons or ligaments is that scar tissue is unorganized which can cause a decrease in elasticity and hamper overall mobility of the new tissue. With stem cells helping to orchestrate the arrangement of new tissue, scars are less bulky and more mechanically useful, transforming the injured tissue as close to its original state as possible.


Platelet-Rich Plasma (PRP) Regenerative Therapy


Most people understand the purpose of platelets for clotting, but platelets do a lot more than help stop blood. Rich in chemicals called growth factors, platelets stimulate tissue healing. Therefore, when administered in concentrated quantities to an injured site, these platelets can get a jump-start on the healing process.


IRAP Regenerative Therapy


When the body is injured, lots of chemical molecules are released that send signals telling various cells to take multitudes of actions in the healing process. Interleukin-1 is one of these chemical molecules and its role is to increase inflammation. As explained before, some inflammation is necessary to initiate healing, but ongoing inflammation is detrimental. IRAP therapy blocks interleukin-1, thereby decreasing inflammation at an injury site.


Like the other therapies, IRAP is made directly from the injured horse. A blood sample is taken, and then incubated in a special way that increases IRAP. This is then re-injected in the horse, usually into an injured joint.


As with all new technologies, there are still many obstacles to overcome with these new modalities. Firstly, there are few standards to adhere to when using these therapies. There are not yet any FDA-approved regenerative medicines on the market for horses and lack of regulatory oversight can mean great variations in the end product that is administered to the patient. Additionally, much more research is needed to fully understand the mechanisms by which some of these therapies work, or at what dose they work best. Still, the advent of these new options is exciting and gives hope to some cases that, maybe twenty years ago, had no hope of recovery. They aren’t miracle drugs, but an extra tool in the toolbox is always helpful.


Dr. Anna O'Brien


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