Idiopathic pulmonary arterial hypertension remains an enigma for physician in both diagnosis and treatment. Existing biomarkers, tissue characteristics and definite treatment are restricted. There are many evidences suggested that Apelin-APJ system associated with Idiopathic Pulmonary Arterial Hypertension (IPAH). A comprehensive characterise circulating peptide levels and investigate any tissue gradients of apelin in patients with idiopathic pulmonary arterial hypertension and healthy volunteers might provide important information about pathophysiologic process and diagnostic marker. In addition, first time human study to assessment the effect of exogenous apelin infusion on exercise performance in healthy volunteers and patients with idiopathic pulmonary arterial hypertension is essential to confirm whether the relevance between animal models and clinical subjects.
