MMP induction and inhibition in myocardial infarction

Short-term survival following a myocardial infarction (MI) has greatly improved, due in part to therapeutic interventions that restore blood flow and limit infarct size. The increased incidence of infarct-stimulated left ventricular (LV) remodeling that advances to congestive heart failure (CHF), however, is a significant long-term complication and a leading cause of mortality. Changes to ECM structure and function are primary components of IV remodeling and are precipitated by the early increase in infarct area collagen levels that replace necrotic myocytes and form a scar. ECM turnover is coordinated through the synthesis and degradation of ECM and non-ECM components, particularly the matrix metalloproteinases (MMP), a family of proteolytic enzymes that cleave ECM. MMPs have multiple roles in remodeling events that lead to IV dilation. The inhibition or targeted deletion of specific MMPs attenuates IV remodeling events post-MI. MMP inhibitors have been used in animal models to delineate IV remodeling mechanisms and to evaluate the pharmacologic potential of targeting the ECM to modify IV remodeling post-MI. This review summarizes the current knowledge and limitations of MMP inhibition in the post-MI myocardium.