P2Y12 inhibition in macrophages reduces ventricular arrhythmias in rats after myocardial ischemia-reperfusion.

Abstract

Myocardial ischemia-reperfusion (I/R) injury is still thought to be an unsolved puzzle that may lead to reperfusion arrhythmias and sudden cardiac death. Inflammation plays a key role in myocardial I/R. Studies have indicated that purinoceptor 2Y12 (P2Y12) antagonists have anti-inflammatory properties that are cardioprotective. In this study, we explored whether inhibition of P2Y12 in macrophages could reduce cardiac inflammation and attenuate reperfusion arrhythmias after myocardial I/R. Rats were randomly divided into 4 groups: group A (control + vehicle); group B (control + P2Y12 shRNA lentiviral vector); group C (myocardial I/R + vehicle); and group D (myocardial I/R + P2Y12 shRNA lentiviral vector). Infarct size, reperfusion arrhythmias, and P2Y12 and platelet endothelial cell adhesion molecule-1 (CD31) protein expression were measured. The incidence of reperfusion ventricular tachycardia and fibrillation (VT/VF) was 90% in the I/R group, while it was reduced to 50% by P2Y12 shRNA treatment. Ionized calcium binding adapter molecule 1 and P2Y12 immunoreactivity in the myocardial I/R + P2Y12 shRNA group was lower compared to the myocardial I/R group. P2Y12 shRNA treatment increased α-smooth muscle actin (α-SMA) and CD31 protein expression, as evidence by western blot and immunohistochemistry analyses (0.31 ±0.01 compared to 0.26 ±0.008, group D compared to group C, p < 0.05). Inhibition of P2Y12 in macrophages improved reperfusion arrhythmias in our rat I/R model, suggesting that blocking P2Y12 could decrease the inflammatory response after cardiac perfusion.