[Roles of Sodium-Glucose Cotransporter 1 (SGLT1) in the Induction of Cardiac Remodeling].

　It is well-known that metabolic remodeling occurs in the presence of cardiomyopathy induced by cardiac ischemia and hypertrophy, and diabetes mellitus. It is also known that a novel cardiac glucose transporter, sodium-glucose co-transporter 1 (SGLT1), is expressed in the human heart. However, the role of SGLT1 in the development of cardiac metabolic remodeling is still unclear. Recent studies demonstrated that SGLT1 activation improves ischemia-reperfusion-induced cardiac injury, and increased SGLT1 gene expression is observed in hypertrophic, ischemic, and diabetic cardiomyopathy in human hearts. Moreover, increases in SGLT1 protein expression cause cardiac remodeling such as hypertrophy and increased interstitial fibrosis in mice. We demonstrated that ischemia-reperfusion-induced cardiac injury was potentiated in SGLT1-deficient mice. In contrast, chronic pressure overload induced by transverse aortic constriction (TAC) caused cardiac hypertrophy and reduced left ventricular fractional shortening in C57BL/6J wild-type mice. Moreover, the TAC-induced hypertrophied heart showed increased SGLT1 and AMPKαprotein expressions. These results suggest the different effects of SGLT1 activation on cardiac diseases such as acute ischemia-reperfusion-induced cardiac injury and chronically-induced cardiac hypertrophy. Thus, SGLT1 may be a novel therapeutic target for the treatment of patients with cardiac diseases such as ischemic and hypertrophic cardiomyopathy.