FOXO1 and cardiac hypertrophy: To better understand the role of FoxO1 in mediating regression of cardiac hypertrophy, we created an in vitro model of regression of cardiac hypertrophy in which cardiomyocytes were cultured in collagen-I-coated special culture dishes, subjected to repetitive mechanical stretch for 36 hours and subsequently incubated without stretch (de-stretch) for the same length of time (Fig. 5A).