Involvement of Apelin/APJ axis in thrombogenesis in valve heart disease patients with atrial fibrillation

Abstract

The mechanism underlying thrombosis in atrial fibrillation (AF) is not yet clearly understood. The apelin/ APJ axis parallel and counter-regulate with the angiotensin system. The present study hypothesizes that apelin/ APJ axis exert its anti-thrombus effect in normal left atrial tissue and is disrupted by up-regulated reninangiotensin- aldosterone system (RAAS) signaling during AF. The specimens of left atrial appendages collected from patients with rheumatic mitral stenosis who underwent valve replacement were divided into 3 groups: sinus rhythm, AF + /thrombus - , and AF + /thrombus + . The amounts of angiotensin II receptor subtype 1 (AT1), apelin/ APJ and its downstream plasminogen activator inhibitor-1 (PAI-1) were detected by western blot. The expression of apelin/APJ was significantly decreased in the AF + /thrombus + group compared with the sinus rhythm and AF + /thrombus- groups. Meanwhile the expressions of AT1 and PAI-1 were highest in the AF + /thrombus + group compared to the other two groups. Taken together, the present study reveals apelin/APJ axis might be correlated with thrombosis in patients with AF mediated by PAI-1.