Role of a selective aldosterone blocker in mice with chronic heart failure

Spironolactone, a nonselective aldosterone blocker, has a cardioprotective effect; however, significant endocrine side effects limit its use. Eplerenone is a new selective aldosterone blocker. We investigated whether eplerenone attenuates cardiac remodeling and improves function in a mouse model of heart failure and whether coadministration of eplerenone and an angiotensin-converting enzyme inhibitor (ACEi) provides better cardioprotection than either agent alone.

C57BL/6J mice were subjected to myocardial infarction (MI) by ligating the left anterior descending coronary artery. Two weeks later, the mice were either left untreated or treated with (1) eplerenone, (2) ACEi, or (3) eplerenone plus ACEi for 12 weeks. Systolic blood pressure (SBP) was measured and echocardiography performed before MI and weekly thereafter. At the end of the study, interstitial collagen fraction (ICF) and myocyte cross-sectional area (MCSA) were examined histologically. We found that (1) eplerenone significantly improved ejection fraction and cardiac output and decreased left ventricular (LV) systolic area, LV weight, ICF, and MCSA independently of changes in SBP compared with untreated animals; (2) ACEi had similar beneficial effects, accompanied by a significant reduction in SBP; and (3) combined treatment offered limited additional benefit beyond monotherapy.

In mice with MI, eplerenone attenuates progression of heart failure comparably to ACEi, and its effect is independent of BP lowering.