Analysis of serum and synovial fluid biomarkers for detection of early stage osteoarthritis and to compare efficacy of intra-articular treatment with triamcinolone and triamcinolone with hyaluronate

Abstract

Summary Reasons for performing study: To evaluate the potential of biomarkers in serum and synovial fluid samples to diagnose horses with early stage osteoarthritis and to monitor the response on therapy. Objectives: Analysis of serum and synovial fluid biomarkers for detection of early stage osteoarthritis and to compare efficacy of intra-articular treatment with triamcinolone and triamcinolone with hyaluronate in horses with clinical joint disease. Methods: In total 80 horses owned by clients from 13 veterinary clinics were included. At baseline lameness scores were assessed and serum and synovial fluid samples were taken before intra-articular treatment with triamcinolone or triamcinolone with hyaluronate was administered. 3 weeks after intra-articular treatment serum samples were taken and lameness scores were assessed by the same veterinarian. Biomarkers (CCL2, PGE2, total MMP and GAG) in serum and synovial fluid were analysed and compared to positive and negative control groups. Clinical efficacy is evaluated comparing clinical outcome with the reduction/elevation of biomarkers in % of both treatment groups. Results: Serum concentrations of CCL2, PGE2, total MMP and GAG showed no significant difference between the negative and positive control group, serum concentrations at baseline and 3 weeks after IA treatment of the patients with clinical joint disease did not differ or were significantly lower compared to healthy horses. CCL2 concentrations in paired serum samples showed a significant reduction (average of 32%) 3 weeks after IA treatment, but no significant difference between treatments groups or correlation to clinical outcome was found. Synovial fluid concentrations of total MMP and GAG measured at baseline were significantly higher compared to healthy horses. Synovial fluid concentration of CCL2 and PGE2 of the patient group was significantly lower compared to the negative control group, while the positive control group showed significantly higher concentrations. Conclusions: Serum concentrations of CCL2, PGE2, total MMP and GAG of a single serum sample can’t be used for detection of early stage OA as normal values can’t be set. Measuring CCL2 concentrations in repeated serum samples of individual horses can be used to monitor the amount of inflammation as a response to treatment. Results indicate synovial fluid total MMP and GAG concentrations have potential to be used for diagnostics and prognosis as an indirect and direct biomarker of cartilage degeneration. Reduction of CCL2 is not correlated to clinical outcome and no significant difference of efficacy was found comparing both treatments. More research is needed before analysis of serum and synovial fluid biomarkers can be used in practical settings for diagnosis and prognosis of early stage OA.