To investigate the correlation between synovial fluid (SF) concentrations of metalloproteinase (MMP) -2, -3, and -9, tissue inhibitors of metalloproteinases (TIMP)-1 and -2, chondroitin 4-, 6-sulfate (deltadi-C4S, deltadi-C6S), hyaluronic acid (deltadi-HA), antigenic keratan sulfate (KS), and radiologic grade in patients with rheumatoid arthritis (RA) and to assess the clinical value of these factors as disease markers.
Enzyme linked immunoassays and high performance liquid chromatography were used. SF samples were collected from 52 patients with RA. Radiographic (Larsen grade) and clinical evaluations were also done.
There was no significant correlation between the concentrations of MMP, TIMP, and deltadi-C4S, deltadi-C6S, deltadi-HA, and antigenic KS. No significant correlations were found between the radiologic grade and the concentrations of MMP or TIMP in SF. There was a significant increase in the concentration of antigenic KS and deltadi-C6S/deltadi-C4S ratio in SF from patients with Larsen grade 2 compared to grade 5. A significant correlation between deltadi-C6S and antigenic KS concentrations in SF was observed.
Although there were large variances between the samples in this study, proteoglycan metabolism in the cartilage matrix of the patients with RA might have been increased in the early phases of tissue destruction and decreased in advanced stages because of scanty cartilage tissue. The concentrations of MMP-2, -3, -9 and TIMP-1, -2 in SF did not seem to be influenced by the amount of residual cartilage.