Protective effect of ACE- and kininase-inhibitor on the onset of cardiomyopathy

Abstract

Attempts at treating idiopathic cardiomyopathy have been made both clinically and experimentally using the cardiomyopathic Syrian hamster. In recent years, the angiotensin converting enzyme (ACE) inhibitor has attracted considerable attention as an agent to treat heart failure. We administered the ACE inhibitor captopril to the cardiomyopathic hamster. In this study, 15 mg/kg body weight of captopril was administered to the cardiomyopathic hamster J2N at 5 weeks of age for 10 weeks; age matched J2N hamsters were used as non-treated control animals. At the end of captopril administration, blood was collected from the ventral aorta. Serum malondialdehyde (MDA), serum CPK, aldolase and LDH were determined, and myosin isoenzyme patterns of the extirpated myocardium were compared. Additionally, ECGs were compared and the fibrotic ratio of both ventricles determined. Serum MDA, CPK, and aldolase increased significantly in the cardiomyopathic hamster, whereas these indices were significantly inhibited in the hamster treated with captopril. The pathological ECG findings and the ventricular V3 predominant myosin isoenzyme patterns of the J2N were also much improved in the captopril group. However, the improvement in these parameters by enalapril administration was less than that seen with captopril. These results suggested that the effect of captopril is not only due to decrease of the angiotensin II level, but also due to increase in tissue kinin and vasodilatory prostaglandin which play an important role in the beneficial effect of captopril.