Beneficial Effects of Combined Blockade of ACE and AT1 Receptor on Intimal Hyperplasia in Balloon-Injured Rat Artery

Abstract

Objective—The present study was undertaken to elucidate the effect of the ACE inhibitor and the angiotensin II type 1 (AT1) receptor antagonist in combination on neointimal hyperplasia after balloon injury. Methods and Results—Temocapril (an ACE inhibitor), CS-866 (an AT1 receptor antagonist), or their combination was given orally to rats, and their effects were compared on vascular hyperplasia induced by balloon injury. The maximal preventive effect of temocapril and CS-866 alone on neointimal thickening after balloon injury was obtained at a dose of 20 and 10 mg/kg per day, respectively. However, compared with either agent alone, combined temocapril and CS-866 (20 and 10 mg/kg per day, respectively) prevented intimal thickening to a larger extent. Furthermore, compared with either agent alone, combined temocapril and CS-866 prevented vascular smooth muscle cell proliferation in the intima more potently. The increase in platelet-derived growth factor receptor tyrosyl phosphorylation was reduced more potently by the combination of both agents compared with either agent alone. The nonpeptide bradykinin B2 receptor antagonist or the NO synthase inhibitor reduced the prevention of intimal thickening by combined temocapril and CS-866. Conclusions—Compared with either agent alone, the combination of an ACE inhibitor and an AT1 receptor antagonist is more effective in the prevention of vascular hyperplasia due to bradykinin or NO.