Effect of apelin/APJ in retinal vascular diseases

The G protein-coupled receptor was deorphanized with cloning of the APJ-endogenous ligand apelin, which is an important active peptides.Apelin/APJ system is widely distributed in central nervous system, cardiovascular system, immune system and endocrine system.Therefore, apelin plays important physiological and pathological roles in blood pressure regulation, fluid homeostasis, potent inotropic, insulin sensitivity regulation, pituitary hormone release, human immunodeficiency virus (HIV) entry inhibition, etc.Recently, the studies found apelin/APJ system also regulates the vasculogenesis and angiogenesis of retina through inducing cell proliferation, migration and tube formation in endothelium.The experiments in vivo also demonstrate apelin/APJ system plays a role in physiological and pathological retinal vascular formation.This review summarizes the evidence of apelin in physiological retinal vascular diseases and diabetic retinopathy, retinopathy of prematurity and choroidal neovascular ization.