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.
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