Triple ACE-ECE-NEP inhibition in heart failure: a comparison with ACE and dual ECE-NEP inhibition.

Mortality remains high in chronic heart failure (CHF) because under ACE inhibitor treatment other neurohumoral systems remain/become (de)activated, such as the endothelin and atrial natriuretic peptide pathways. Dual endothelin-converting enzyme-neutral endopeptidase (ECE-NEP) inhibition exerts beneficial effects in experimental CHF, but whether "triple" ACE-ECE-NEP inhibition is superior to ACE or ECE-NEP inhibition is unknown. We compared, in rats with CHF, ACE-ECE-NEP to ACE or ECE-NEP inhibition in terms of left ventricular (LV) hemodynamics and remodeling. Benazepril (2 mg/kg/d) or the ECE-NEP inhibitor CGS26303 (10 mg/kg/d) were administered alone or in combination (subcutaneously for 28 days starting 7 days after coronary ligation). ACE-ECE-NEP inhibition reduced blood pressure more markedly than ACE or ECE-NEP inhibition. All treatments increased cardiac output to the same extent, but ACE-ECE-NEP inhibition reduced LV diameter and LV end-diastolic pressure more markedly than ACE or ECE-NEP inhibition. The reduction of LV weight and collagen accumulation in the "viable" myocardium was most pronounced after ACE-ECE-NEP inhibition. These results, obtained in experimental CHF, illustrate a further improvement of LV hemodynamics and structure after ACE-ECE-NEP inhibition compared with either ACE or ECE-NEP inhibition, but whether this is associated with a further improvement of exercise tolerance and/or survival remains to be determined.