Active synovial matrix metalloproteinase-2 is associated with radiographicerosions in patients with early synovitis

Serum and synovial tissue expression of the matrix metalloproteinase (MMP)- 2 and -9 and their molecular regulators, MMP-14 and TIMP-2 was examined in 28 patients with inflammatory early synovitis and 4 healthy volunteers and correlated with the presence of erosions in the patients. Immunohistologica l staining of MMP-2, MMP-14 and TIMP-2 localized to corresponding areas in the synovial lining layer and was almost absent in normal synovium. Patient s with radiographic erosions had significantly higher levels of active MMP- 2 than patients with no erosions, suggesting that activated MMP-2 levels in synovial tissue may be a marker for a more aggressive synovial lesion.