Evidence for a role of iron-catalyzed oxidants in functional and metabolic stunning in the canine heart.

Abstract

Brief (15-minute) coronary occlusion and subsequent reperfusion lead to prolonged functional and metabolic abnormalities (stunned myocardium). Previous work suggests that one factor responsible for this phenomenon is oxygen-derived free radicals. The formation of the highly reactive hydroxyl radical requires the presence of metal ions, most importantly iron. In the present study, the effect of the iron-chelator deferoxamine on the recovery of segment shortening (%SS) in the stunned myocardium was compared with a control group in barbital anesthetized dogs. Deferoxamine (500 mg intra-atrially) was administered 15 minutes prior to and throughout 15 minutes of coronary occlusion. %SS, regional myocardial blood flow, hemodynamics, and myocardial high-energy phosphates were measured. Areas at risk, collateral blood flow, and all hemodynamic parameters were similar between control and deferoxamine-treated animals. While deferoxamine did not prevent the loss of systolic wall function that occurred during ischemi...