Extracellular matrix metalloproteinase inducer (EMMPRIN) is increased in human left ventricle after acute myocardial infarction.

BACKGROUND AND AIMS Elevated activities of matrix metalloproteinases (MMPs) following acute myocardial infarction (AMI) have been shown to mediate ventricular remodeling. The extracellular MMP inducer (EMMPRIN) plays a key regulatory role for MMP activities. The aim of this study was to evaluate changes of EMMPRIN, MMP-2 and MMP-9 and determine the correlation between EMMPRIN expression and MMPs in human left ventricle after AMI. METHODS Immunohistochemistry for MMP-2, MMP-9 and EMMPRIN were performed postmortem in 15 human left ventricles including 10 patients with AMI and five normal subjects who were accident victims. Western blot was used to determine protein levels of MMP-2, MMP-9 and EMMPRIN. The correlation between EMMPRIN expression and MMPs was determined by linear regression. RESULTS Our results showed that there was slight EMMPRIN expression on the membranes of normal cardiac myocytes, whereas its expression strongly increased around the zone of necrosis in the AMI group. Compared with the control group, EMMPRIN (1.10+/-0.17 vs. 0.25+/-0.04, p<0.001), MMP-2 (0.25+/-0.03 vs. 0.64+/-0.11, p<0.001) and MMP-9 (0.16+/-0.03 vs. 0.39+/-0.07, p<0.001) protein levels were significantly increased in the AMI group. The expression of MMP-2 (r(2)=0.82, p<0.001), and MMP-9 (r(2)=0.424, p=0.041) were correlated with EMMPRIN expression in AMI patients. CONCLUSIONS Our findings demonstrate for the first time that EMMPRIN expression increases in the human left ventricle after AMI. As one of the upregulators of local MMP expression, augmented expression of EMMPRIN may play a critical role in ventricular remodeling in AMI subjects.