Combined high-fat, high-sucrose diet and streptozotocin treatment induces cardiometabolic heart failure with preserved ejection fraction in mice.

Diabetes is associated with an increased incidence of heart failure with preserved ejection fraction (HFpEF), but the underlying mechanisms are poorly understood. A shortage of mouse models reflecting the diverse HFpEF pathophysiology contributes to this inadequate understanding of disease mechanisms. We conducted a comprehensive analysis of a nongenetic, inducible type 2 diabetes mellitus (T2DM) mouse model about its suitability as a preclinical model of cardiometabolic, diabetes-induced HFpEF. T2DM was induced in C57Bl/6 mice by a high-fat/high-sucrose diet and a low-dose streptozotocin (DIO-STZ). Cardiac function was assessed in vivo by echocardiography and left ventricular catheterization and in vitro using the isolated perfused heart. Structural, molecular, and bioenergetic disturbances were analyzed by immunohistochemistry, RNA-seq, qPCR, Western blot, and extracellular flux analysis of myocardial tissue. Blood glucose, fatty acids, and ketone body levels were elevated, and insulin levels were reduced in DIO-STZ compared with chow. DIO-STZ mice showed an HFpEF phenotype with reduced cardiac output, end-diastolic volume, and increased filling pressure. No differences in myocardial fibrosis or in vitro stiffness were detected between DIO-STZ and chow. RNA-Seq pointed toward disturbances in lipid and ketone metabolism. Extracellular flux analysis revealed increased fatty acid oxidation capacity without differences in glucose metabolism. No general mitochondrial dysfunction was observed, but a reduced capacity for β-hydroxybutyrate oxidation. The diabetic DIO-STZ mouse model showed a pronounced functional HFpEF phenotype with underlying mechanisms that remarkably differ from other HFpEF models, making the DIO-STZ model a relevant extension of the range of HFpEF mouse models, especially for investigating molecular mechanisms or therapeutic interventions in diabetes-associated HFpEF.NEW & NOTEWORTHY Heart failure with preserved ejection fraction (HFpEF) is a clinical syndrome whose pathophysiological mechanisms are incompletely understood, potentially due to a lack of preclinical models reflecting the broad range of pathophysiological aspects. We describe a diabetic DIO-STZ mouse model showing a pronounced HFpEF with underlying mechanisms that remarkably differ from other HFpEF models, making this model a relevant extension of the range of HFpEF models, especially for investigating molecular mechanisms or therapeutical interventions in diabetes.