AN ANGIOTENSIN-II RECEPTOR ANTAGONIST REDUCES MYOCARDIAL DAMAGE IN AN ANIMAL-MODEL OF MYOCARDITIS

Background Recently, an angiotensin-converting enzyme inhibitor was shown to have a beneficial effect on virus-induced myocardial injury. We investigated the effect of a new angiotensin II type 1 receptor antagonist, (+/-)-1-(cyclohexyl-oxycarbonyloxy)ethyl 2-ethoxy-1-({[2'-(1H-tetrazol-5-yl)biphe nyl-4-yl]methyl)-1H-benzimidazole-7-carboxylate (TCV-116), in an animal model of viral myocarditis induced by encephalomyocarditis virus. Methods and Results Four-week-old DBA/2 mice were inoculated with the encephalomyocarditis virus. TCV-116 (in 5% gum arabic) was given 1 day before (1 or 10 mg/kg) or 2 days after virus inoculation (0.3 or 3 mg/kg). Control mice received the vehicle only. All drugs were administered orally on a daily basis, and the animals were killed on day 14. When treatment was started 1 day before inoculation, the survival of mice receiving 10 mg/kg of TCV-116 improved (17 of 20 [85%] versus 14 of 22 [64%] control mice), but the difference was not significant. Heart weight (106+/-24 mg versus 133+/-33 mg, P<.05), histological scores for myocardial necrosis (1.1+/-0.3 versus 2.3+/-1.2, P<.01), cellular infiltration (1.4+/-0.7 versus 2.6+/-1.3, P<.05), and calcification (1.1+/-0.3 versus 2.1+/-1.1, P<.01) were significantly decreased in mice given TCV-116 at 3 mg/kg compared with the vehicle control mice. The plasma angiotensin II level was significantly higher in infected mice than in noninfected mice (71.8+/-30.2 versus 31.8+/-22.5 pg/mL, P<.05). TCV-116 did not inhibit viral replication in the heart. Conclusions This study suggests that angiotensin II plays an important pathophysiological role in viral myocarditis. Treatment with TCV-116, an angiotensin II receptor antagonist, had a cardioprotective effect.