The ACE-inhibitor captopril improves myocardial perfusion in spontaneously diabetic (BB) rats.

The aim of this study was to examine the influence of inhibition on angiotensin converting enzyme (ACE) of myocardial function and perfusion of the rat impaired by diabetes. Spontaneously diabetic rats were treated with the ACE-inhibitor captopril for 4 months. Cardiac performance was analysed in the isolated heart perfused at constant volume. Epicardial perfusion was determined by measuring changes in epicardial fluorescence after injection of a bolus of fluoresceinisothiocyanate-dextrane (3 kDa) as described previously. As compared to untreated diabetic controls, captopril prevented the increase of end diastolic pressure, coronary perfusion pressure and vascular resistance. The intravascular volume was enlarged and the epicardial perfusion rate increased in hearts of diabetic rats treated with captopril as compared to diabetic controls. Treatment of diabetic rats with the ACE-inhibitor captopril (1) increases the number of perfused capillaries, and (2) can partly prevent the development of cardiac dysfunction in diabetes. Together with morphological data demonstrating an inhibition of interstitial and perivascular fibrosis in hearts of diabetic rats treated with captopril, our data suggest that ACE-inhibition is cardioprotective in diabetes. These observations are also compatible with the assumption that an accelerated generation of angiotensin II may be involved in the pathophysiological chain of events leading to diabetic cardiopathy.