Beneficial effects of quinaprilat on coronary vasomotor function, endothelial oxidative stress, and endothelin activation after human heart transplantation

We evaluated the potential of angiotensin-converting enzyme inhibition (ACEI) to modulate resting coronary vasomotor tone and endothelial dysfunction, and to decrease vascular oxidative stress and endothelin (ET)-1 activity in human heart transplant recipients. Coronary vasomotor responses and transcardiac metabolism of glutathione, oxidized glutathione, and ET-1 were determined before and after quinaprilat infusion in 32 heart transplant recipients. Furthermore, the potential effects of ACEI on endothelial oxidative stress, ET-1 activity, and nitrosoglutathione formation were investigated using endothelial cell cultures. Epicardial diameter increased in response to quinaprilat by 6% +/- 1% (proximal segments; P