Influence of polymorphonuclear leukocytes and plasma on coronary vasomotion after ischemia

Background. The role of plasma and neutrophils in endothelial dysfunction following myocardial ischemia was investigated. Methods. Isolated rabbit hearts were perfused at constant pressure with a modified Krebs-Henseleit solution. After a 30-minute global ischemia the hearts were perfused at the onset of reperfusion for 10 minutes with either NaCl (group I, n = 6), autologous plasma alone (group II, n = 5), autologous polymorphonuclear leukocytes alone (PMN, group III, n = 6), or PMN and plasma in combination (group IV, n = 5). Before and after ischemia the effects of intracoronary endothelial dependent and independent vasodilation by acetylcholine (1 × 10−7mol/L) and glycerol trinitrate (1 × 10−6mol/L) were investigated. Results. A similar increase in coronary flow was induced in groups I, II, and III by acetylcholine and glycerol trinitrate before and after ischemia. In contrast, in group IV the endothelial dependent vasodilation was significantly depressed (p< 0.05). In groups II and IV a moderate but significant reduction in the recovery of the left ventricular pressure was observed after ischemia and reperfusion. Conclusions. These results suggest that after myocardial ischemia, plasma is required for neutrophil-mediated endothelial dysfunction.