Continued Efforts to Diagnose Joint Diseases in Horses

In an effort to prolong the performance careers of horses, veterinary researchers continue to search for solutions to the diagnostic and therapeutic challenges of osteoarthritis and osteochondrosis.

“Many sectors of the equine industry rely on radiographs to assess the health and stability of the horse’s musculoskeletal system. These pictures can provide valuable information regarding the presence of lesions that need to be addressed immediately as well as information on the horse’s future ability to perform in athletic venues and in breeding programs,” explained Catherine Whitehouse, M.S., a nutrition advisor for Kentucky Equine Research.

Radiographs present some diagnostic and interpretation challenges. As such, other methods of assessing joint health would be of great value to the equine industry in minimizing lameness, wastage of horses, and economic losses.

In a recent attempt to identify other diagnostic tools to assess joint health, European researchers^* hypothesized that measuring blood markers of joint inflammation and cartilage breakdown might work. They selected four markers to compare with the radiographic findings of joint health and disease: insulin growth factor-I, myeloperoxidases, collagen type 2-1 (Coll2-1), and its nitrated form, Coll2-1NO₂.

The markers were selected based on data collected in other studies on joint diseases in which changes in blood levels of these molecules could predict a problem. Type 2 collagen, for example, is a protein found only in articular cartilage. Elevated levels of type 2 collagen is recognized as a “diagnostical, prognostical, and burden of disease marker in human osteoarthritis,” explained the researchers.

To evaluate the usefulness of these markers on joint health, the researchers evaluated 63 stallions between the ages of two and six. All horses underwent standard “stud book admission” examinations, including orthopedic assessment and radiographs. In addition, blood was collected and analyzed for the four markers.

Unfortunately, the researchers reported, “results failed to demonstrate the hypothesis that the radiological score could be predicted by the combination of the selected biochemical markers.”

In this study, only Coll2-1NO_2, a marker for inflammation and cartilage degradation, was identified as a potential predictor of the osteoarticular status of horses. Specifically, circulating Coll2-1NO₂ levels were higher in horses with radiographically evident lesions. The researchers suggested that markers of cartilage synthesis should also be analyzed to potentially improve the ability to predict the existence of bone or joint lesions.

“Considering the lack of highly reliable means of predicting and assessing joint disease and inflammation in horses, protecting these delicate structures remains a highly recommended means of maximizing long-term joint health,” advised Whitehouse. “Offering joint supplements containing glucosamine, chondroitin sulfate, hyaluronic acid, and omega-3 fatty acids supports healthy joints and can even protect joints prior to trauma.”

Look for KER’s collection of joint products.

*Coppelman, E.B., F.H. David, F. Tóth, et al. The association between collagen and bone biomarkers and radiographic osteoarthritis in the distal tarsal joints of horses. Equine Veterinary Journal. In press.