Association between plasma apelin levels and coronary collateral development in patients with stable angina pectoris.

Apelin is an endogenous ligand for the orphan G protein-coupled receptor (APJ receptor). Apelin is predominantly expressed in endocardial and vascular endothelial cells, while APJ receptor is localized to endothelial and smooth muscle cells, and cardiomyocytes. Apelin has recently attracted much attention due to its promotive effects on angiogenesis and its protective effects against mycardial infarction. In this issue of Atherosclerosis, Akboga et al. investigated plasma apelin levels in patients with stable angina and severe coronary artery stenosis and provided the first evidence that higher plasma apelin levels are associated with better coronary collateral development, suggesting that apelin plays a role in coronary collateral development.