Insulin-like growth factor I as a cardiac hormone: Physiological and pathophysiological implications in heart disease

Accumulating evidence has indicated that insulin-like growth factor-1 (IGF- 1) plays a specific role in the intricate cascade of events of cardiovascul ar function, in addition to its well established growth-promoting and metab olic effects, IGF-1 is believed to mediate many effects of growth hormone ( GH). IGF-1 promotes cardiac growth, improves cardiac contractility, cardiac output, stroke volume, and ejection fraction. In humans, IGF-1 improves ca rdiac function after myocardial infarction by stimulating contractility and promoting tissue remodeling. Furthermore, IGF-1 facilitates glucose metabo lism, lowers insulin levels, increases insulin sensitivity, and improves th e lipid profile, These data suggest an attractive therapeutic potential of IGF-1. Both clinically observed and experimentally induced impairments of c ardiac function are also found to be associated with abnormal IGF-1 levels. IGF-1 and its binding proteins have been considered as markers for the pre sence of certain cardiac abnormalities, indicating that IGF-1 may be a risk factor for certain cardiac disorders. The present review will emphasize th e role of IGF-1 in the regulation of cardiac growth and function, and the p otential pathophysiological role of IGF-1 in cardiac function. (C) 1999 Aca demic Press.