ACE2 downregulation contributes to adverse cardiovascular and reproductive outcomes in female mice on high fat diet.

Obesity is a growing concern among women of reproductive age, as it can significantly impact both maternal and fetal health. A potential mechanism linking obesity to cardiometabolic dysfunction is the imbalance between the classical (pressor) and the compensatory (protective) arms of the renin angiotensin system (RAS). The objective of this study was to investigate how high fat diet (HFD) impacts cardiovascular and reproductive health in female mice and its associated mechanisms with an emphasis on the protective angiotensin converting enzyme 2 (ACE2)/Angiotensin (Ang)-(1-7) axis. Female C57BL/6J mice at 8 weeks of age were assigned to either a HFD (60% kcal fat) or a regular diet (RD, 22 kcal% fat). Following 10-12 weeks' dietary exposure, HFD-fed females exhibited significantly greater weight gain and glucose intolerance compared to RD-fed controls. Telemetry recordings revealed that HFD exposure led to significantly elevated blood pressure (BP), increased heart rate, reduced spontaneous baroreflex sensitivity, and dampened parasympathetic tone. The above cardiometabolic dysfunction persisted or further exacerbated during pregnancy. Although HFD exposure did not alter fertility (ability to conceive), delivery or litter size, offspring from HFD mothers suffered low birth weight and markedly increased postnatal mortality. Examination of the RAS revealed reduced ACE2 mRNA and protein expression in both the heart and the kidney of HFD-fed females. Importantly, Ang-(1-7) infusion in HFD-fed females starting two weeks before mating improved glucose tolerance, reduced BP, and improved offspring survival. In conclusion, downregulation of ACE2/Ang-(1-7) axis contributes to HFD-induced cardiometabolic and reproductive dysfunction in female mice.