Evaluation of left ventricular function following myocardial infarction in adult postnatally overfed mice

Abstract

Perinatal environment, such as nutritional state, is of major importance for short- and long-term cardio-metabolic status. Postnatal overfeeding (PNOF) induced in rodents by litter size reduction at birth reproduces the effects of childhood overnutrition and was shown to affect the cardiovascular function and to predispose to cardiovascular pathologies. The aim of our work was to follow the evolution of cardiac function for 28 days after in vivo myocardial infarction in control or PNOF mice. C57BL/6 male mice were raised in litter adjusted to 9 or 3 pups for control and PNOF group respectively. After weaning, mice of both groups had free access to standard diet and water. At 4 months, they were subjected to permanent ligation of the left anterior descending artery (LAD) to induce myocardial infarction or to sham surgery. Echocardiographic measurements were acquired at baseline and 1, 7, 15 and 28 days after surgery for cardiac function evaluation. Twenty-eight days after surgery, the left ventricle (LV) and lungs were weighed and infarct size was assessed. At basal state, no difference of cardiac function was observed between the 4 groups. In both control and PNOF mice subjected to LAD ligation, the fractional area change (FAC) was significantly decreased 24 h after surgery and the systolic/diastolic LV area was significantly increased 7 d after surgery, and both remained stable until 28 d. However, no differences neither in LV contractile function nor in infarct size were noticed between control and PNOF mice, except for an increased LV mass in PNOF mice. While all groups of mice subjected to myocardial infarction developed heart failure, as demonstrated by decreased LV contractility and dilation, there were no differences between control and PNOF groups. Further measures will be done in order to assess circulating biomarkers as cardiac troponin I (cTnI), brain natriuretic peptide (BNP) and growth differentiation factor-15 (GDF-15).