Elevated circulatory MMP-2 and MMP-9 levels and activities in patients with rheumatoid arthritis and systemic lupus erythematosus

Objectives Matrix metalloproteinases (MMPs) are suggested to play important roles in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). This study is to examine the MMPs expressions and activities in Taiwanese RA and SLE patients. Design and methods Levels and activities of plasma MMP-2 and MMP-9 were investigated by enzyme-linked immunosorbent assay and zymography, respectively. Results MMP-2 levels in control subjects, RA and SLE patients were 146.1 ± 34.2, 194.0 ± 24.2 and 208.9 ± 75.9 ng/mL respectively, and for MMP-9 were 51.4 ± 57.1, 567.7 ± 313.1 and 208.7 ± 105.5 ng/mL respectively. Both MMP-2 and MMP-9 levels and activities from all patients were significantly higher than that from control subjects. Conclusions MMP-2 levels in both patients groups were approximately 1.3–1.4 folds higher than that in control subjects, notably, MMP-9 levels were 11- and 4-folds significantly higher, respectively, in RA and SLE patients. The results which MMP-2 and MMP-9 levels and activities are significantly elevated support the involvement of MMPs proteins in these autoimmune disorders.