Increased matrix metalloproteinase 2 expression in vascular smooth muscle cells cultured from abdominal aortic aneurysms

Objectives: Recent evidence has implicated matrix metalloproteinase 2 (MMP-2) in the pathogenesis of aneurysms. The aim of this study was to examine MMP-2 production and expression by aortic smooth muscle cells (SMCs) and dermal fibroblasts derived from patients with abdominal aortic aneurysms (AAAs). Methods: Aortic SMCs and dermal fibroblasts were cultured from patients with AAAs or from age-matched controls with atherosclerosis. The production of MMP and tissue inhibitor of metalloproteinase into culture media was analyzed with the use of gelatin zymography, Western blotting, and enzyme-linked immunosorbent assay. Gene expression was analyzed with Northern blotting. Results: All cells studied constitutively produced MMP-2. Aortic SMCs cultured from aneurysmal tissue expressed MMP-2 protein and messenger RNA at a significantly higher level than SMCs from controls (P = .008). Dermal fibroblasts from patients with AAAs expressed MMP-2 at a similar level to controls. In both cell types, tissue inhibitor of metalloproteinase 2 and membrane type 1-MMP were expressed at similar levels. Conclusions: These data suggested that the regulation of MMP-2 gene expression was altered in the aortic SMCs of patients with aneurysms, but this finding was not repeated in other mesenchymal tissue.