Angiotensin II receptor antagonist TCV-116 reduces graft coronary artery disease and preserves graft status in a murine model - A comparative study with captopril

Background Despite the current progress in immunosuppressive regimens, the incidence of graft coronary artery disease (CAD) after cardiac transplantation has not decreased. Recent study has revealed that angiotensin-converting enzyme (ACE) inhibition decreases CAD in rats; however, it is not clear whether this beneficial effect of ACE inhibition is due to a decrease in production of angiotensin II (Ang II) or inhibition of bradykinin degradation. To determine whether Ang II type 1 receptor (AT(1)-R) blockade has an inhibitory effect on CAD, we evaluated the effects of TCV-116, an, AT(1)-R antagonist, in a murine model of cardiac transplantation. Methods and Results Hearts of DBA/2 mice (H-2(d)) were transplanted heterotopically to B10.D2 mice (H-2(d)). Recipients were treated orally with TCV-116 (10 mg/kg per day), captopril (100 mg/kg per day), or vehicle only. Graft status, as assessed by palpation and inspection at laparotomy 70 days after transplantation, was preserved better in the TCV-116-treated group (P<.005) and in the captopril-treated group (P<.05) than in the vehicle-treated group. Intimal area in the graft coronary arterial wall decreased to 31% in the TCV-116-treated group (P<.001 versus vehicle-treated group) and to 34% (P<.005) in the captopril-treated group but was 45% in the vehicle-treated group. Fibrotic lesions of the left ventricle were less prominent in the TCV-116-treated (31%; P<.01 versus vehicle-treated group) and captopril-treated groups (33%; P<.05) than in the vehicle-treated group (54%). Conclusions These findings show that AT(1)-R blockade is at least as effective as ACE inhibition in management of chronic allograft rejection and suggest that Ang II may play an important role in chronic allograft rejection.