Apelin is the endogenous ligand of the G protein-coupled receptor, APJ. Vascular smooth muscle cells express both apelin and APJ, which are important regulatory factors in the cardiovascular and nervous systems. Importantly, APJ is also involved in the pathogenesis if HIV-1 infection. We investigated whether vascular smooth muscle cell proliferation was regulated through an apelin-pERK1/2-cycli...

Apelin, the endogenous ligand of the G protein-coupled receptor (APJ), plays an important role in the physiological response to homeostatic perturbations. The aim of the present study was to investigate the effect of apelin on the functions of peritoneal macrophages. A double staining immunofluorescence technique was used to determine the expression of APJ in peritoneal macrophages. Rat periton...

The hypothalamus is a key element of the neural circuits that control energy homeostasis. Specific neuronal populations within the hypothalamus are sensitive to a variety of homeostatic indicators such as circulating nutrient levels and hormones that signal circulating glucose and body fat content. Central injection of apelin secreted by adipose tissues regulates feeding and glucose homeostasis...

BACKGROUND To assess cardiovascular actions of APJ agonism during prolonged (Pyr(1))apelin-13 infusion and renin-angiotensin system activation. METHODS AND RESULTS Forty-eight volunteers and 12 patients with chronic stable heart failure attended a series of randomized placebo-controlled studies. Forearm blood flow, cardiac index, left ventricular dimensions, and mean arterial pressure were me...

OBJECTIVE Apelin is an endogenous ligand for the G protein-coupled receptor, APJ, and participates in multiple physiological processes. To identify the roles of endogenous apelin, we investigated the phenotype of apelin-deficient (apelin-KO) mice. METHODS AND RESULTS Apelin-KO mice showed impaired retinal vascularization and ocular development, which were analyzed by histology, immunohistoche...

Angiogenesis involves the formation of new blood vessels by sprouting or splitting of existing blood vessels. During sprouting, a highly motile type of endothelial cell, called the tip cell, migrates from the blood vessels followed by stalk cells, an endothelial cell type that forms the body of the sprout. To get more insight into how tip cells contribute to angiogenesis, we extended an existin...

Blood vessels change their caliber to adapt to the demands of tissues or organs for oxygen and nutrients. This event is mainly organized at the capillary level and requires a size-sensing mechanism. However, the molecular regulatory mechanism involved in caliber size modification in blood vessels is not clear. Here we show that apelin, a protein secreted from endothelial cells under the activat...

Apelin and its receptor APJ constitute a signaling pathway best recognized as an important regulator of cardiovascular homeostasis. This multifunctional peptidergic system is currently being described to be involved in embryonic events which extend into vascular, ocular and heart development. Additionally, it is highly expressed in pulmonary tissue. Therefore, the aim of this study was to inves...

Apelin and its cognate G protein-coupled receptor APJ constitute a signaling pathway with a positive inotropic effect on cardiac function and a vasodepressor function in the systemic circulation. The apelin-APJ pathway appears to have opposing physiological roles to the renin-angiotensin system. Here we investigated whether the apelin-APJ pathway can directly antagonize vascular disease-related...

We studied whether apelin-13 is cardioprotective against ischemia/reperfusion injury if given as either a pre- or postconditioning mimetic and whether the improved postischemic mechanical recovery induced by apelin-13 depends only on the reduced infarct size or also on a recovery of function of the viable myocardium. We also studied whether nitric oxide (NO) is involved in apelin-induced protec...