Expression of slow skeletal TnI in adult mouse hearts confers metabolic protection to ischemia

► Isoform changes in myofilament proteins induce changes in cardiac metabolic phenotype. ► Expression of the ssTnI, in place of adult cTnI, induces metabolic protection to ischemic stress. ► Adult mouse hearts expressing ssTnI exhibit augmented glycolytic ATP production during ischemia. ► Expression of fetal ssTnI induces resistance to hypoxia, due to ischemia, similar to fetal hearts.