Myocardial extra-cellular matrix and its regulation by metalloproteinases and their inhibitors

Cardiovascular disease poses a major health care burden in the Western world. Following myocardial injuries, ventricular remodelling and dysfunction ensue, which can eventually culminate in heart failure. An important event in left ventricular (LV) remodelling is alteration of the extracellular matrix (ECM) integrity, the structural network that interconnects the myocardial components. The critical role of ECM remodelling in cardiac dilation and heart failure was recognized more than a decade ago, and the molecular factors responsible for this process are now being explored. Abnormal ECM turnover is primarily brought about by an imbalance in the activity of matrix metalloproteinases (MMPs) that degrade ECM components, and their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMPs). Here we provide an overview of composition of the cardiac ECM, and alterations in ECM regulatory proteins, MMPs and TIMPs, in human heart disease. We also discuss the role of TIMPs, MMPs, and a disintegrin and metalloproteinase (ADAMs) enzymes in cardiac development and function as learned through genetically altered mouse models.