Increased MMP-3 Levels in Sera from Patients with Rheumatoid Arthritis

Metalloproteinase-3 (MMP-3) plays a role in the destruction of the cartilage matrix in rheumatoid arthritis (RA). In this study, MMP-3 serum levels in patients with RA and osteoarthritis (OA) were measured by immunoassay, and comparisons were made between patients with early RA and patients with progressive RA and OA. In addition, correlations between serum MMP-3 levels and classical clinical parameters and other molecular indexes that indicate the disease activity of RA, were investigated. Furthermore, trends in the concentrations of molecular indexes were analyzed and the changes in MMP-3 concentrations were observed over a period of one year. MMP-3 serum levels were significantly higher in early and progressive RA than in OA. Elevated MMP-3 serum levels seem to appear during the early stage of RA when joint destruction is not yet severe. Significant correlations were found between MMP-3 levels and many clinical parameters that indicate inflammation (TIMP-1, HA, plt, ESR, CRP, Fe, TIBC, Ferrit, ALP, WBC, joint score) in patints with early RA. CRP, Fe, HA and ICTP levels correlated positively with MMP-3 levels in progressive RA, though the number of parameters that correlate with MMP-3 levels decreased. Changes in MMP-3 levels over the course of one year were similar to those of CRP in most cases. However, some cases with progressive RA showed a wider variation, and their MMP-3 levels did not correlate with CRP. HA, ICTP and TIMP-1 concentrations showed similar tendencies to that of MMP-3 in patients with RA. Our studies suggest that changes in MMP-3 serum levels reflect both joint inflammation and joint destruction and can be used as a marker for both conditions. Monitoring of MMP-3 levels may be useful for early and differential diagnoses and the assessment of present joint activity as well as the patient's response to treatment, especially during early stage of the disease. MMP-3 levels may also be useful in predicting the degree of joint destruction, especially in progressive RA