Influence of sex on ventricular remodeling after myocardial infarction in mice

Murine models are increasingly used to elucidate the molecular mechanisms contributing to left ventricular (LV) remodeling. Epidemiologic and animal studies have suggested that women undergo differing patterns of LV remodeling than men after myocardial infarction (MI). We, therefore, sought to compare LV remodeling after MI in male and female mice. Echocardiography was performed in male and female C57BL6 mice before and serially after MI. Two days after MI, end-diastolic LV internal diameter and shortening fraction were similar in males and females. Between days 2 and 28 after MI, LV internal diameter increased in male mice but remained unchanged in female mice. During this time period, shortening fraction declined in males, but not in females. Posterior wall thickness increased more in females than in males. The size of the MI and the LV mass/body weight were similar between the 2 sexes after MI. Echocardiography showed that after MI, female mice undergo less extensive LV remodeling than males, with less dilation and better preserved LV systolic function 28 days after MI. These sex differences should be taken into account when studying murine cardiac adaptation to MI.