Postnatally overfed mice display cardiac function alteration following myocardial infarction

Background: Cardiovascular (CV) pathologies remain a leading cause of death worldwide, often associated with common comorbidities such as overweight, obesity, type 2 diabetes or hypertension. An innovative mouse model of metabolic syndrome induced by postnatal overfeeding (PNOF) through litter size reduction after birth was developed experimentally. This study aimed to evaluate the impact of PNOF on cardiac remodelling and the development of heart failure following myocardial infarction. Methods: C57BL/6 male mice were raised in litter adjusted to 9 or 3 pups for normally-fed (NF) control and PNOF group respectively. After weaning, all mice had free access to standard diet and water. At 4 months, mice were subjected to myocardial infarction (MI). Echocardiographic follows-up were performed up to 6-months post-surgery and biomolecular analyses were carried-out after heart collection. Findings: At 4 months, PNOF mice exhibited a significant increase in body weight, along with a basal reduction in left ventricular ejection fraction (LVEF) and an increase in left ventricular end-systolic area (LVESA), compared to NF mice. Following MI, PNOF mice demonstrated a significant decrease in stroke volume and an increased heart rate compared to their respective initial values, as well as a notable reduction in cardiac output 4-months after MI. After 6-months, left ventricle and lung masses, fibrosis staining, and mRNA expression were all similar in the NF-MI and PNOF-MI groups. Interpretation: After MI, PNOF mice display signs of cardiac function worsening as evidenced by a decrease in cardiac output, which could indicate an early sign of heart failure decompensation.