APJ polymorphisms in coronary artery disease patients with and without hypertension

Apelin is an endogenous peptide that increases cardiac inotropism through its APJ receptor. Certain findings indicate that the apelinergic system may have a pathophysiological role in cardiovascular disease and there is evidence showing the role of the apelinergic system in blood pressure regulation in vitro and in animal models. The role of the apelin-APJ system in cardiovascular physiology and its interaction with other neuroendocrine pathways has not been fully elucidated. However, the small number of reported studies indicates that apelin signaling may be involved in the regulation of blood pressure, cardiac contractile function, fluid balance, angiogenesis and inhibition of apoptosis. We evaluated the possible relationship between the G212A and A445C APJ polymorphisms and coronary artery disease (CAD) in Italian patients and in healthy controls by RFLP-PCR. We analyzed the allelic and genotypic frequencies of APJ polymorphisms in 664 patients (378 with hypertension) and 143 controls. There were no differences between allelic and genotypic frequencies in patients in respect to the controls for both polymorphisms analyzed. In the CAD population, there was an increased frequency of the G212 allele in patients with hypertension in respect to patients without hypertension. No differences were present in the two subgroups for the A445C polymorphism. Although the functional role of the G212A polymorphism has not yet been identified, it is possible to hypothesize that the presence of the A allele may cause a gain in function of the apelin/APJ system associated with a lower risk of hypertension.