Angiotensin-(1-7) attenuates the development of heart failure after myocardial infarction in rats

The renin-angiotensin system (RAS) is a key player in the progression of heart failure. Angiotensin-(1-7) is thought to modulate the activity of the RAS. Furthermore, this peptide may play a part in the beneficial effects of angiotensin-converting enzyme inhibitors in cardiovascular disease. We assessed the effects of angiotensin-(1-7) on the progression of heart failure. Male Sprague-Dawley rats underwent either coronary ligation or sham surgery. Two weeks after induction of myocardial infarction, intravenous infusion of angiotensin-(1-7) (24 microg/kg per hour) or saline was started by minipump. After 8 weeks of treatment, hemodynamic parameters were measured, endothelial function was assessed in isolated aortic rings, and plasma angiotensin-(1-7) levels were determined. Myocardial infarction resulted in a significant deterioration of left ventricular systolic and diastolic pressure, dP/dt, and coronary flow. Raising plasma levels 40-fold, angiotensin-(1-7) infusion attenuated this impairment to a nonsignificant level, markedly illustrated by a 40% reduction in left ventricular end-diastolic pressure. Furthermore, angiotensin-(1-7) completely preserved aortic endothelial function, whereas endothelium-dependent relaxation in aortas of saline-treated infarcted rats was significantly decreased. Angiotensin-(1-7) preserved cardiac function, coronary perfusion, and aortic endothelial function in a rat model for heart failure.