The growth hormone and insulin-like growth factor 1 axis in heart failure

Experimental data suggests that growth hormone and IGF-1 have beneficial ef fects on myocardial function in animal models of heart failure. Preliminary evidence suggests an abnormality in the growth hormone-IGF-l axis in heart failure with relative growth hormone resistance. Beneficial effects of gro wth hormone and IGF-1 include vasodilatation, stimulation of cardiac hypert rophy, increase in calcium sensitivity of cardiac myofilaments and preventi on of apoptosis. Recently, cardiac cachexia has been shown to be a powerful negative predictive factor in heart failure. Cachectic patients have highe r angiotensin II levels. In the rat there is an important interaction betwe en the renin-angiotensin system and IGF-1. Thus, angiotensin II infusion ca uses weight loss in part through a catabolic effect. This effect results fr om increased protein degradation. Angiotensin II reduces circulating and sk eletal muscle IGF-1 but increases IGF-1 and the IGF-IR expression in cardia c muscle. Preliminary data suggest a potential beneficial effect of growth hormone in heart failure. Further trials are necessary to test the potentia l beneficial effect of growth hormone and/or IGF-1 in heart failure.