Combination of genetic eNOS deficiency and high-fat diet induces reproducible cardiometabolic HFpEF.

Heart failure with preserved ejection fraction (HFpEF) is a complex, multi-organ cardiometabolic syndrome lacking universally effective therapies. We developed and validated a robust murine model leveraging complete, constitutive genetic endothelial nitric oxide synthase deficiency (eNOS KO) coupled with metabolic stress via a high-fat diet (HFD) in both male and female cohorts. eNOS KO mice subjected to HFD (10 weeks for males; 15 weeks for females) developed a severe and highly reproducible cardiometabolic HFpEF phenotype. Despite preserved left ventricular ejection fraction, both sexes exhibited profound diastolic dysfunction, characterized by elevated E/e' ratios and left ventricular end-diastolic pressures (LVEDP), alongside severe exercise intolerance. Consistent with the systemic clinical syndrome, pathological remodeling extended to multi-organ damage, featuring prominent cardiac fibrosis, severe hepatic steatosis, and renal tubulointerstitial fibrosis. Finally, chronic administration of the dual GIP/GLP-1 receptor agonist tirzepatide largely reversed the hemodynamic, functional, and systemic fibrotic derangements. In conclusion, this novel eNOS KO mouse + HFD model provides a rapidly developing, highly penetrant, and chemically unconfounded platform that ensures robust HFpEF induction across both sexes. This model can be readily adopted for the investigation of mechanistic insights into HFpEF pathobiology and for the study of novel HFpEF therapeutics.