Effective inhibition of tissue angiotensin-converting enzyme attenuates pressure-overload aortic hypertrophy in early stage in rats

Trandolapril, an angiotensin-converting enzyme (ACE) inhibitor, has been reported to have higher efficiency on tissue ACE than other ACE inhibitors. In this study, effect of trandolapril on pressure-overload cardiovascular hypertrophy in early stage was examined in rats by comparing with the effect of enalapril. Rats with abdominal aorta banded or sham-operated were orally treated with trandolapril (1 mg/kg/day), enalapril (2O mg/kg/day), or vehicle for 2 weeks after the surgical maneuvers. In vehicle-treated rats, the banding raised intra-aortic pressure, maximum velocity ofpressure rise, left ventricular (LV) weight, LV ACE activity, and aortic mass. Although both ACE iuhibitors equally reduced the aortic pressure, only trandolapril elicited a significant prevention of the aortic hypertrophy. In contrast, cardiac hypertrophy was insignificantly prevented by either inhibitor. The LV ACE activity was completely inhibited by traldolapril, whereas insignificantly suppressed by enalapril. These results suggest that effective inhibition of tissue ACE attenuates the 2-week pressure overload-induced hypertrophy of the aorta but not of the LV.