Background: Takayasu arteritis (TA) is a chronic vasculitis that primarily affects large elastic arteries. Monitoring of disease activity is crucial because the disease tends to progress despite treatment with glucocorticoid and/or immunosuppressive agents. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) have generally been used as disease activity markers, but these are nonspecific inflammatory markers and lack the sensitivity and specificity to accurately monitor the disease status. Given the histological findings characterized by destruction of elastic fibers, we hypothesized that matrix metalloproteinases (MMPs) could be useful as markers of disease activity in TA.
Methods and results: A consecutive series of 25 patients with TA were enrolled in this study. According to the National Institutes of Health criteria of disease activity, 11 were in an active phase and the remaining 14 were in remission. Circulating levels of MMP-2, MMP-3, and MMP-9 were determined by ELISA in all patients with TA and controls. MMP-2 levels were higher in patients with TA than in controls, but no correlation was found between serum MMP-2 and disease activity score. In contrast, MMP-3 and MMP-9 levels in patients with active disease were higher than in patients in remission and controls, and a positive correlation was demonstrated between circulating levels of MMP-3 or MMP-9 and disease activity score. The high levels of MMP-3 and MMP-9 improved when patients underwent remission.
Conclusions: The present results indicate that MMP-2 can be helpful in diagnosing TA and that MMP-3 and MMP-9 can be used as activity markers for TA.