Decreased MMP-9 activity in the serum of patients with diffuse cutaneous systemic sclerosis

Abstract

Summary Matrix metalloproteinase‐9 (MMP‐9) and its inhibitor, tissue inhibitors of metalloproteinases‐1 (TIMP‐1) are involved in tissue inflammation and fibrotic processes. We previously reported an elevated serum TIMP‐1 level in patients with systemic sclerosis (SSc). We measured serum TIMP‐1 and active MMP‐9 levels in 62 patients with SSc, 10 patients with rheumatoid arthritis (RA) and 15 normal controls using a modified enzyme‐linked immunosorbent assay. The active MMP‐9 level in the serum of the patients with RA or SSc was not significantly different from that of controls. Serum MMP‐9 activity in patients with diffuse cutaneous SSc was significantly decreased compared with that of limited cutaneous SSc or normal controls. The MMP‐9 activity and modified‐Rodnan total skin thickness score in patients with SSc were negatively correlated. Serum MMP‐9 activity and TIMP‐1 level in patients with SSc were not correlated. Serum MMP‐9 activity might be a useful indicator of disease activity, especially skin severity, in SSc patients.