Increased Endoplasmic Reticulum Stress in Atherosclerotic Plaques Associated With Acute Coronary Syndrome A Balancing Act Between Plaque Stability and Rupture

Acute coronary syndrome (ACS) represents a series of indications of sudden cardiac ischemia that involve a variety of causes, including acute myocardial infarction and unstable angina.1 ACS usually is associated with thrombus formation in the coronary artery or coronary artery vasospasm, resulting in myocardial ischemia. 2 Thrombus formation may involve platelet adhesion and degranulation on damaged or dysfunctional endothelium overlying the intact or ruptured atherosclerotic plaque, as well as microthrombi.3 Atherosclerotic plaque rupture represents a series of deleterious events linked to the breakdown of the fibrous cap. This process may occur as a result of the increased secretion of matrix metalloproteinases by lesion resident macrophages or enhanced apoptotic cell death within the fibrous cap. However, viable smooth muscle cells (SMCs) within the fibrous cap synthesize interstitial collagen fibers that enhance the structural integrity of the plaque and prevent its rupture.4