Nanosecond pulse electric field activation of platelet-rich plasma reduces myocardial infarct size and improves left ventricular mechanical function in the rabbit heart.

In the current study, we used the novel, nonchemical method of nanosecond pulsed electric fields (nsPEF) to investigate the efficiency of a protocol involving the in vivo treatment of the ischemic and reperfused heart and heart cells in culture with platelet-rich plasma (PRP). Associated with the restoration of blood flow to the ischemic tissue is a phenomenon referred to as "ischemic reperfusion injury." Clinically a type of reperfusion injury occurs during coronary bypass surgery once blood perfusion to the heart is restarted. Although the restoration of oxygen to ischemic myocardial cells is critical for tissue survival, reperfusion causes myocardial oxidative stress, attributable in part to the increased production of reactive oxygen species (ROS). Enhanced ROS production is associated with mitochondrial damage. Adult female New Zealand white rabbits were anesthetized and a left thoracotomy performed to expose the heart. The distal segment of the left anterior descending coronary artery was occluded for 15 minutes and then released so reperfusion of the tissue could occur. PRP (.21 mg/heart) or saline was injected into the ischemic area of the myocardium. Mechanical function of the left ventricle was analyzed using a Millar catheter attached to a Micro-Med Analysis System. H9c2 cells in culture were treated with 1 mL of nsPEF activated PRP (1.05 mg/flask) for 24 hours before analysis for ROS production or mitochondrial depolarization damage). The left ventricle contracted and relaxed faster and infarct size was reduced in hearts treated with PRP compared with saline. ROS production and mitochondrial depolarization were reduced in H9c2 cells treated with PRP and stimulated with hydrogen peroxide. These results provide evidence that nsPEFs can successfully be used to prepare PRP and that the PRP is functional in heart protection possibly by reducing ROS generation and stabilizing the mitochondria of the ischemic/reperfused heart.