Role of Leukocytes in Coronary Vascular Endothelial Injury Due to Ischemia and Reperfusion

A possible cause of the coronary endothelial injury that occurs with ischemia and reperfusion is the local accumulation of leukocytes during these events. To investigate the role of leukocytes in coronary endothelial injury, we tested the effect of leukocyte removal by filtering on coronary endothelial function in a canine model of regional myocardial ischemia and reperfusion. Blood was supplied to the left anterior descending and circumflex arteries of anesthetized dogs via an extracorporeal circulation. A 60-minute left anterior descending occlusion was followed by 120 minutes of reperfusion either with (n=6) or without (n=6) leukocyte filters in the extracorporeal circuit. Regional myocardial blood flow was measured with radiolabeled microspheres. Radiolabeled autologous transferrin (In) and erythrocytes (Tc) were given intravenously during reperfusion for assessment of microvascular permeability. Left anterior descending and circumflex coronary artery rings were assessed in vitro for endothelium-dependent dilation to acetylcholine, ADP, and thrombin. In unfiltered dogs, ischemia and reperfusion increased the protein leak index of ischemic myocardium 2.3-fold compared with that of nonischemic myocardium (2.3±0.5 to 5.2±1.6, p