Circulating IGF-I levels are associated with increased biventricular contractility in top-level rowers.
BACKGROUND
The intensive physical activity is often associated with cardiac changes.


OBJECTIVE
(i) To evaluate the IGF-I system and myocardial structure and function by standard Doppler echocardiography and Tissue Doppler in athletes and sedentary controls; and (ii) to determine any relationship between IGF-I system and echocardiographic parameters.


METHODS
Nineteen male top-level rowers and 19 age-matched healthy sedentary male controls underwent blood determination of fasting serum IGF-I, IGFBP-3 and acid-labile subunit levels and standard Doppler echocardiography combined with pulsed Tissue Doppler of posterior septal wall, left ventricular (LV) lateral mitral annulus and right ventricular (RV) tricuspid annulus. Myocardial presystolic (PS(m)), systolic (S(m)), the ratio of early diastolic (E(m)) to atrial (A(m)) velocities as well as myocardial time intervals were calculated.


RESULTS
Rowers had higher serum IGF-I levels (P = 0.04), higher biventricular cavity dimensions and wall thicknesses compared to controls. They also had better LV and RV myocardial function than controls. In the rowers, IGF-I was associated with LV ejection fraction (r = 0.50, P = 0.03), RV PS(m) velocity (r = 0.55, P = 0.01) and with RV myocardial precontraction time (r = -0.57, P = 0.01). These associations remained significant after adjusting for age and heart rate.


CONCLUSIONS
Top-level athletes showed higher IGF-I levels and a better myocardial performance than controls, particularly for the RV systolic activity. The independent correlations between IGF-I and systolic parameters of the left (ejection fraction) and right (PS(m) velocity and precontraction time) ventricles may possibly indicate a role of IGF-I system in the modulation of myocardial inotropism in athletes. Further studies are needed to confirm this hypothesis.
Vitale
Giovanni
G
Department of Molecular and Clinical Endocrinology and Oncology, University of Naples Federico II, Naples, Italy.
Galderisi
Maurizio
M
Colao
Annamaria
A
Innelli
Pasquale
P
Guerra
Germano
G
Guerra
Ermelinda
E
Dini
Frank Lloyd
FL
Orio
Francesco
F
Soscia
Antonio
A
De Divitiis
Oreste
O
Lombardi
Gaetano
G
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D015150:Echocardiography, Doppler; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000378:metabolism; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D013177:Sports / Q000502:physiology*; D016276:Ventricular Function / Q000502:physiology*; D055815:Young Adult
D007334:Insulin-Like Growth Factor I