MMP2 and heart failure: The activation of MMP-2 by ONOO− leads to the formation of active 72 kDa intracellular MMP-2 [8], which is implicated in the degradation of critical intracellular targets in the contractile machinery of cardiomyocytes during ischemia and reperfusion, such as troponin I [22], alpha-actinin [21], titin [16] and light chain myosin [20], probably leading to heart failure.