Osteoarthritis, or arthritis as it is known, is the most common cause of lameness in racehorses. It is usually diagnosed late in the course of the disease when the joint damage is long-standing and there are no good treatment options. With the aim of identifying small changes long before the horse becomes lame, researchers at the Swedish University of Agricultural Sciences (SLU) are working to develop reliable markers for osteoarthritis in horses.
Osteoarthritis is the most common cause of lameness in racehorses
In osteoarthritis, the joint cartilage breaks down and fragments of tissue from the joint are released into the joint fluid and blood. Researchers at SLU have identified an interesting degradation product from articular cartilage, a fragment of the COMP protein, which could potentially be used as an osteoarthritis marker. A recent study investigated whether the COMP fragment can be measured in normal blood samples and used to distinguish between healthy and sick horses.
By developing antibodies specifically targeting the COMP fragment, the researchers were able to develop an ELISA test and detect the fragment in blood. Horses were then monitored by blood sampling during light exercise and rest, to see how the fragment varies with circadian rhythm. In addition, blood levels of the fragment were compared in healthy and acutely lame horses.
Horses with acute lameness have markedly elevated concentrations of the COMP marker in their blood
The daily rhythm and light exercise did not affect the concentration of the COMP fragment in the blood. In contrast, horses with acute lameness had markedly elevated concentrations of the marker in the blood compared to healthy horses.
The study shows that the COMP fragment can be used as a marker for osteoarthritis in acutely ill horses and work is continuing to find out if the marker can also identify earlier stages of disease.
Link to the publication: https://doi.org/10.1111/evj.13082
Ekman S, Lindahl A, Rüetschi U, Jansson A, Björkman K, Abrahamsson-Aurell K, Björnsdóttir S, Löfgren M, Hultén LM, Skiöldebrand E. "Effect of circadian rhythm, age, training and acute lameness on serum concentrations of cartilage oligomeric matrix protein (COMP) neo-epitope in horses". Equine Vet J. 2019 Sep;51(5):674-680.
Text from SLU's website.