Dual ET(A)-ET(B) receptor antagonism improves metabolic syndrome-induced heart failure with preserved ejection fraction.

BACKGROUND: Metabolic syndrome (MetS) is a multifaceted disease associated with heart failure (HF), which affects the vascular system. The endothelin (ET) system is a key player in MetS and HF; therefore, targets for ET receptors are of therapeutic interest. OBJECTIVES: This study sought to evaluate the effects of macitentan, a dual endothelin receptor antagonist (ERA), in a rat model of MetS-induced heart failure with preserved ejection fraction (HFpEF). METHODS: We assessed in 12-week-old Zucker fa/fa rats the effects of macitentan (10 mg/kg/day as a food additive for short-term/7- or long-term/90-day treatment) on right ventricular (RV) and left ventricular (LV) function/remodelling (MRI), RV and LV haemodynamics (catheterization) and RV and LV coronary function (myograph). RESULTS: After 7- and 90-days, untreated Zucker fa/fa rats presented isolated LV diastolic dysfunction (illustrated by elevated LV end-diastolic pressure [EDP] and LV end-diastolic pressure-volume relationship [EDPVR] without changes in LV EDPVR). This was associated with increased collagen deposition and impaired endothelium-dependent coronary artery relaxation. Macitentan 7- and 90-day treatment significantly decreased blood pressure and prevented LV, RV and coronary dysfunctions and long-term treatment reduced LV collagen density. Moreover, 7- and 90-day macitentan treatment significantly reduced cardiac inflammation and reactive oxygen species (ROS) production. CONCLUSIONS: Dual ERA macitentan improved both LV and RV diastolic dysfunction. This was associated with improved coronary vasodilation, diminished cardiac oxidative stress and improved blood composition. These results suggest that antagonizing the ET system with macitentan is a promising approach to treat HFpEF and its complications.