Differential effects of Mas receptor deficiency on cardiac function and blood pressure in obese male and female mice

Angiotensin-(1–7) [ANG- (1–7)] acts at Mas receptors (MasR) to oppose effects of angiotensin II (ANG II). Previous studies demonstrated that protection of female mice from obesity-induced hypertension was associated with increased systemic ANG-(1–7), whereas male obese hypertensive mice exhibited increased systemic ANG II. We hypothesized that MasR deficiency (MasR^-/-) augments obesity-induced hypertension in males and abolishes protection of females. Male and female wild-type (MasR^+/+) and MasR^-/- mice were fed a low-fat (LF) or high-fat (HF) diet for 16 wk. MasR deficiency had no effect on obesity. At baseline, male and female MasR^-/- mice had reduced ejection fraction (EF) and fractional shortening than MasR^+/+ mice. Male, but not female, HF-fed MasR^+/+ mice had increased systolic and diastolic (DBP) blood pressures compared with LF-fed controls. In HF-fed females, MasR deficiency increased DBP compared with LF-fed controls. In contrast, male HF-fed MasR^-/- mice had lower DBP than MasR^+/+ mice. We quantified cardiac function after 1 mo of HF feeding in males of each genotype. HF-fed MasR^-/- mice had higher left ventricular (LV) wall thickness than MasR^+/+ mice. Moreover, MasR^+/+, but not MasR^-/-, mice displayed reductions in EF from HF feeding that were reversed by ANG-(1–7) infusion. LV fibrosis was reduced in HF-fed MasR^+/+ but not MasR^-/- ANG-(1–7)- infused mice. These results demonstrate that MasR deficiency promotes obesity-induced hypertension in females. In males, HF feeding reduced cardiac function, which was restored by ANG-(1–7) in MasR^+/+ but not MasR^-/- mice. MasR agonists may be effective therapies for obesity-associated cardiovascular conditions. NEW & NOTEWORTHY MasR deficiency abolishes protection of female mice from obesity-induced hypertension. Male MasR-deficient obese mice have reduced blood pressure and declines in cardiac function. ANG-(1–7) infusion restores obesity-induced cardiac dysfunction of wild-type, but not MasR-deficient, male mice. MasR agonists may be cardioprotective in obese males and females.