Abstract 611: The Kinin B1 Receptor Contributes to the Cardioprotective Effect of ACE Inhibitors and Angiotensin Receptor Blockade
Activation of the kinin B2 receptor contributes to the cardioprotective effect of angiotensin- converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB), whereas the role of B1 remains unclear. We previously showed that mice lacking B1 (−/ −) had increased LV mass and chamber dilatation, indicating that B1 exert a physiological role in maintaining cardiac structure and function. We further hypothesized that kinins acting on B1 partially contribute to the cardiac beneficial effect of ACEi or ARB. Female B1−/ − mice and wild-type controls (C57BL/6J, B1+/+) were subjected to sham MI or MI by ligating the left anterior descending coronary artery. Three weeks after MI, each strain was treated with vehicle, ACEi (ramipril, 2.5 mg/kg/day in drinking water) or ARB (valsartan, 40 mg/kg/day in drinking water) for 5 weeks. LV ejection fraction (EF) and LV diastolic dimension (LVDd) were evaluated by echocardiography. Infarct size was studied histologically. SBP and EF did not differ between strains in sham-MI and decreased similarly after MI in both B1+/+ and B1−/ −. Infarct size was similar among groups. However, B1−/ − had a greater LV mass and LVDd either at baseline or after MI. ACEi and ARB significantly increased EF and decreased LVDd and these effects were diminished in B1−/ − (Table⇓), although SBP decreased to a similar degree in both strains. Our data suggest that kinins acting on the B1 receptor may exert a cardioprotective role and contribute to the cardiac beneficial effects of ACEi and ARB.