The cardiac microRNA that shields the heart from reperfusion

Researchers have identified a microRNA that may help protect the heart from myocardial ischaemia/reperfusion injury, a problem that still lacks an effective drug treatment. A team led by Liwenjing Xu and Qiyu Sun at the Affiliated Hospital of Chengde Medical University reports that miR-486—an abundant microRNA in cardiac tissue—can blunt damage after blood flow returns. Using rats, they delivered miR-486 via an adeno-associated virus vector, AAV9, injected into tail veins three weeks before inducing heart attack. After ligating the left anterior descending coronary artery for 30 minutes, they restored reperfusion. Compared with controls, treated rats showed better cardiac function 72 hours later, including higher left ventricular ejection fraction and fractional shortening on echocardiography. Infarct size was smaller, and tissue analysis showed reduced early collagen deposition, suggesting less adverse matrix remodeling.