Preservation of Left Ventricular function and Coronary Flow by Angiotensin I-Converting Enzyme Inhibition in the Hypertensive-Diabetic Dahl Rat

The effect of the angiotensin I-converting enzyme (ACE) inhibitor benazepril (55 mg/kg orally) on the preservation of cardiac performance in diabetichypertensive'Dahl S rats was investigated. Diabetes mellitus was produced by streptozotocin. Fasting (4-h) blood glucose levels were 279 ± 50 mg/dL in diabetic Dahl salt-sensitive ν 79 ± 5 mg/dL in nondiabetic Dahl salt-sensitive rats. Cardiac performance was determined at the end of 8 weeks in an isolated perfused working heart apparatus. Peak left ventricular pressure (LVPm a x ) , left ventricular peak negative dP/dt, and coronary flow were depressed in diabetic Dahl S rats (P < .05 ν control). These deficits in cardiac function were not observed in diabetic Dahl S rats chronically treated with benazepril. The beneficial effects of benazepril apparently were independent of systolic blood pressure reduction. Although plasma ACE activity was increased in diabetic Dahl S rats, plasma renin activity was reduced. This suggests that the beneficial effects of ACE inhibition may be due to an effect upon the kinin system rather than the renin-angiotensin system. The benazeprilassociated preservation of cardiac function in this study suggests that ACE inhibitors may be beneficial in the treatment of diabetic heart disease. Am J Hypertens 1994;7:919–925