Cartilage oligomeric matrix protein and hyaluronan levels in synovial fluid from horses with osteoarthritis of the tarsometatarsal joint compared to a control population.

The research investigates the levels of cartilage oligomeric matrix protein (COMP) and hyaluronan (HA) in the synovial fluid of horses suffering from osteoarthritis in the tarsometatarsal joint, comparing these levels to healthy, control horses in order to understand whether these could be useful indicators in monitoring disease progression and treatment.

Research Objective and Methods

• The primary goal of this research was to quantify the levels of COMP and HA in the synovial fluid from the tarsometatarsal joint, and check for any significant differences in these levels between horses with osteoarthritis and a control population. It aimed to establish a correlation between these levels and any radiographic changes noticed in the horses suffering from osteoarthritis. To carry this out, synovial fluid was collected from the tarsometatarsal joint of 25 lame horses (with osteoarthritis), and 25 healthy horses.
• The concentrations of COMP were measured using a homologous inhibition ELISA while hyaluronan concentration in the synovial fluid was determined using a competition ELISA.
• Radiographic images of the afflicted horses were taken, scored, and then an attempt to correlate the scores with the levels of COMP and HA was conducted.

Results

• The research found that COMP concentrations in the synovial fluid of horses with osteoarthritis were significantly lower than in the fluid from the control group.
• The study also identified an additional fragment band of COMP (approximately 30 kDa) in the afflicted horses, which were not present in the controls.
• However, the study observed no significant differences in HA or the HA:COMP ratio between the patient and control groups.
• They found no correlation between the levels of COMP and HA in the synovial fluid, and the radiographic changes observed.

Conclusion

• The results suggested that lowered COMP levels in the synovial fluid correlate with the presence of osteoarthritis, but these levels cannot be used singularly to establish the stage of the disease.
• The HA levels may not serve as a useful marker for osteoarthritis.
• A noteworthy conclusion drawn was that decrease, rather than increase, in COMP levels might reflect significant loss of cartilage in well-established osteoarthritis cases.
• The researchers suggested future exploration of a specific assay for the COMP fragment correlated with osteoarthritis as it may enable earlier detection of clinical cases.