Heart failure with preserved ejection fraction (HFpEF) is a cardiovascular disease characterized by diastolic dysfunction. Main risk factors include advanced age, sex (women being more susceptible), and comorbidities like obesity, type 2 diabetes, and renal dysfunction. The etiology of the disease is poorly known. Our pathophysiological hypothesis is that metabolic disorders and renal dysfunction induced by the risk factors generate a systemic pro-inflammatory state and hemodynamical changes that, accumulating with age, are responsible for endothelial dysfunction and pathological reorganization of the microvascular morphology, leading to diastolic dysfunction. The objective of the study was, using an HFpEF mouse model, to (1) identify the metabolic disorders and the renal dysfunction, (2) evaluate the pro-inflammatory state, (3) quantify the cardiac microvascular morphology, and (4) characterize the cardiac diastolic function. Experiments were done on 14-week-old female C57BL/Ks mice, predisposed to renal dysfunction, deficient for leptin receptors, and hence developing obesity and type 2 diabetes. 8-week-old male C57BL/6J mice, lacking HFpEF risk factors, were used as healthy control. Glycemia, triglyceridemia, cholesterolemia, and % pro-inflammatory cells were analyzed on blood samples. 3D imaging of glomeruli was done by light-sheet microscopy (LSM) on optically cleared kidneys. 3D imaging of the coronary capillary network was done by LSM on optically cleared hearts. Diastolic pressure, developed pressure, and relaxation rate was measured on Langendorff's isolated perfused hearts. Compared to controls, HFpEF mice showed increased plasmatic glucose, triglyceride, and cholesterol concentration, and increased monocyte and granulocyte %. Their kidneys had decreased glomerular volume, and compactness. The coronary capillary network was altered in the left and right ventricles. Isolated hearts showed left ventricle diastolic dysfunction. Our study suggests that risk factors induce diastolic dysfunction related to coronary microvascularisation morphological alteration via a systemic pro-inflammatory state. Further studies are needed to investigate hemodynamic alteration and endothelial dysfunction.
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