Inverse association between free insulin-like growth factor-1 and isovolumic relaxation in arterial systemic hypertension

Several trials have suggested that insulin-like growth factor-1 (IGF-1) may have a pathophysiological role in the development of arterial essential hy pertension. To verify the possible association of IGF-1 with left ventricul ar morphological and functional echocardiographic parameters in hypertensio n, we studied 40 male patients with newly diagnosed hypertension and 15 nor motensive control subjects. Doppler echocardiography was performed and circ ulating free IGF-1 levels were determined in all subjects. Circulating free IGF-1 levels were higher in hypertensives than in control subjects (P<0.01 ). A significant inverse correlation was observed between free IGF-1 and is ovolumic relaxation time in the overall population (r= -0.37, P<0.01) and i n hypertensives (r= -0.57, P<0.0001), whereas this relation disappears in n ormotensives. These results were confirmed by multivariate analysis. The pr esent study confirms that arterial essential hypertension represents a clin ical condition associated with an increased synthesis of IGF-1. The observa tion of an inverse, independent association between free IGF-1 and isovolum ic relaxation time suggests 2 alternative hypotheses: a possible beneficial effect of IGF-1 to diastolic relaxation or a resistance to IGF-1 in hypert ension.