Platelets contain many growth factors that can be released upon activation.
Transforming growth factor from platelets helps promote new blood-vessel growth, formation of new connective tissue (fibroplasia)
and the re-growth of skin.
Platelet-rich plasma (PRP) therefore has been used to improve healing and help regenerate damaged tissue.
It has been shown to enhance early bone healing.
This blood component is a potent activator of collagenase, which promotes tissue strength and of TGF-b, which stimulates
the deposition of collagen within the wound as a step toward tissue repair.
PRP is prepared by drawing the horse's blood into a specially prepared bag. The blood is processed and eventually a syringe
of PRP is produced.
This preparation can then be injected into the tendon or ligament injury.
Research results are encouraging, but there are no head-to-head comparative studies involving these products. Clients and
DVMs need more information to evaluate and choose these therapies properly.
"Evaluation of clinical cases is ongoing," according to Dr. Andris Kaneps of the New England Medical and Surgical Center in
Dover, N.H., "but our initial results indicate that PRP treatment of tendon and ligament injuries is a tremendous improvement
over other current techniques."
Research shows that one of the main substances responsible for cartilage destruction is interleukin-1 (IL-1). Antibodies against
this destructive substance are known to have a beneficial effect in arresting cartilage damage.
IRAP, or interleukin receptor antagonist protein, is the term for this technology that requires that blood be drawn in a special
The blood tube is then incubated, resulting in a high level of interleukin antibodies. The syringe is centrifuged and the
serum harvested and later injected into the joint in question.
This technique is only minimally invasive. The risks are the same as for any type of joint injection, with infection and scar
formation topping the list.
IRAP is relatively expensive but has no negative effect on cartilage. Because no prohibited substances are administered, there
is no withdrawal time for competition.
Dr. Andrew McDiarmid of Clyde Vet Group in the U.K. say, "Although use of this treatment is still in its early stages, preliminary
results are encouraging and IRAP represents an exciting addition to our therapeutic range in the management of equine lameness."
He adds that most veterinarians in England currently use IRAP on refractory cases that have not responded to conventional
Tildren is another newer drug that is being used for equine joint problems. It is licensed in Europe but not currently in
England or the United States.
Tildren works by regulating bone destruction as it reduces the activity of osteoclasts (bone destroyers) and activates
osteoblasts (bone producers).
Competition horses often have sufficient bone stress to force remodeling into an activated state as the body attempts to thicken
and protect some areas and to lighten and thin others. Tildren slows this overactive process and leads to better overall joint
health. Some horses may experience a mild to more severe colic while receiving Tildren, so caution is warranted and appropriate
treatment should be started if needed.
Tildren is shown to be effective for treating navicular disease but there is some debate about its use in hock arthritis relief.
Overall, it is easy to see why clients and clinicians become overwhelmed and confused as to treatment choices for tendon,
ligament and joint disease in the horse.
Many good practitioners have used PRP, developed a certain comfort level with it and are likely to recommend it to their clients
over other modalities.
An equal number facing similar cases will recommend Acell, Tildren or stem cells.
The follow-up article will feature discussions with surgeons and clinicians.
They will share their clinical experiences with these drugs, techniques and modalities.
And some will discuss the process they use in making their treatment choices.
Marcella is an equine practitioner
in Canton, Ga.