Metalloproteinases-2, -9 and TIMP-1 expression in stable and unstable coronary plaques undergoing PCI.

Introduction: Experimental models and ex-vivo studies suggest a crucial role of some matrix metalloproteinases (MMPs) in the development of acute coronary syndromes, but expression levels of MMP-2, MMP-9 and TIMP-1 in human coronary plaques causing stable angina or an acute coronary syndrome have not been reported, yet. Methods: MMP-2, -9 and TIMP-1 expressions were assessed by real-time PCR from the debris collected into distal protective vascular guards from patients with stable angina (SA-Group, n=16), acute coronary syndrome (ACS-Group, n=16) undergoing percutaneous coronary interventions (PCI). MMP-2 and -9 activities were also evaluated by gelatin-substrate zymography on plasma samples collected immediately before PCI, and compared to those of healthy subjects (Control-Group). Results: The expression of MMP-2 was similar in ACS and SA-Groups. MMP-9 (P=0.011), but not TIMP-1, expression was higher in debris samples from patients in the ACS-Group than in SA-Group. In both groups, the expression of MMP-2 and MMP-9 were inversely correlated (rho=−0.7; Pb0.004). Zymography data indicated that pro and active MMP-9 were higher in ACS than in SA-Group, while no difference in MMP-2 was found. Conclusions: MMP-9, but not TIMP-1 or MMP-2 expression is increased in plaques causing acute coronary syndrome.