Background: This study evaluated whether the nitric oxide precursor L-arginine could reduce ischemia/reperfusion injury by preventing leukocyte-endothelial interactions.
Methods: Normothermic regional ischemia was induced in the open-chest working pig heart for 30 minutes followed by 90 minutes of reperfusion. A preischemic 10-minute intravenous infusion of 4 mg.kg-1.min-1 of L-arginine (n = 12) was compared with 12 control pigs. Nitric oxide release was measured from the coronary sinus using an amperometric probe. Left ventricular function, malonaldehyde, creatine kinase, myocardial oxygen extraction, and the soluble adhesion molecules (intracellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1) were measured.
Results: Nitric oxide release was significantly reduced from baseline throughout ischemia/reperfusion only in the control group. Systolic and diastolic function, and myocardial oxygen extraction were also significantly decreased during early reperfusion in the control compared with the L-arginine group. Peak creatine kinase release was not significantly different between groups. The incidence of ventricular fibrillation, malonaldehyde release, and soluble intracellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1 were each significantly decreased during reperfusion in the L-arginine group.
Conclusions: L-Arginine reduced lipid peroxidation, plasma levels of soluble adhesion molecules, myocardial stunning, and arrhythmias. These results support an excessive endothelial injury/inflammatory response after regional ischemia/reperfusion that can be ameliorated through augmented nitric oxide.