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Effects of exercise training on insulin-like growth factor-I expression in the skeletal muscle of non-cachectic patients with chronic heart failure

2005; SAGE Publishing; Volume: 12; Issue: 4 Linguagem: Inglês

10.1097/01.hjr.0000173106.68485.b7

1741-8275

Rainer Hambrecht, P. Christian Schulze, Stephan Gielen, Axel Linke, Sven Möbius‐Winkler, Sandra Erbs, Jürgen Kratzsch, Andreas Schubert, Volker Adams, Gerhard Schüler,

Nutrition and Health in Aging

Background Chronic heart failure (CHF) is associated with progressive muscle atrophy and reduced local expression of insulin-like growth factor I (IGF-I). Design The present study was designed to test the hypothesis that the local deficiency of IGF-I in the skeletal muscle of patients with CHF would respond to a 6-months aerobic training intervention. Therefore, 18 patients [mean age 52.4 (SD 4.8) years, left ventricular ejection function (LVEF) 27 (SD 6)%] were prospectively randomized to either 6 months of training or sedentary lifestyle. Methods Serum levels of growth hormone (GH) were measured by immunofluorometric assay, IGF-I by competitive solid phase immunoassay. IGF-I expression was assessed in vastus lateralis biopsies by real-time PCR. Results Exercise training led to a significant increase in peak oxygen uptake by 26% [from 20.3 (SD 3.3) ml/kg per min to 25.5 (SD 5.7) ml/kg per min, P=0.003 versus control]. Local expression of IGF-I increased significantly after exercise training by 81% [from 6.3 (SE 0.8) to 11.4 (SE 1.4) relative units, P=0.007 versus control] while IGF-I receptor expression was reduced by 33% [from 20.0 (SE 2.1) to 13.8 (SE 1.7) relative units, P=0.008 versus control]. Serum growth hormone (GH) rose modestly from 0.12 (SE 0.07) to 0.65 (SE 0.37) ng/ml in the training group ( P=0.043 versus baseline), however, this change was not significant compared to the control group ( P=0.848). IGF-I serum levels remained virtually unchanged. Conclusions Exercise training improves local IGF-I expression without significant changes of systemic parameters of the GH/IGF-I axis. These findings indicate that exercise training has the therapeutic potential to attenuate peripheral skeletal muscle alterations in particular with respect to local IGF-I expression in patients with moderate CHF.