Clinical potential of growth hormone in the treatment of congestive heart failure

Substantial evidence supports a role for the growth hormone (GH)/insulin-li ke growth factor 1 (IGF-1) axis in regulation of normal cardiac growth, str ucture and function. Moreover, experimental data suggest beneficial effects of GH and IGF-1 on contractility and peripheral resistance in rats with im paired cardiac function. An increased Ca++ responsiveness is one possible u nderlying cause for the improvement in contractility, although effects of G H and IGF 1 on apoptosis may also play a more long term role for cardiomyoc yte survival. Until recently, studies regarding GH treatment in heart failure were limite d to case reports where administration dramatically improved cardiac functi on. In a small non-blind study of 7 patients with idiopathic dilated cardio myopathy and congestive heart failure (CHF) without GH deficiency who recei ved treatment with recombinant GH (somatropin) for 3 months, considerable i mprovement of cardiac function was reported. More recent studies have demon strated beneficial effects in patients with CHF due to both ischaemic and i diopathic dilated cardiomyopathy, with improvements in haemodynamics when s omatropin was added both as a maintenance therapy and as a short term infus ion. So far, 2 placebo-controlled studies with somatropin as adjunctive therapy in patients with CHF have been reported, although neither study could confi rm previously reported improvement in systolic function and lowering of wal l stress. In summary, it is clear that further placebo-controlled clinical trials are mandatory to verify positive effects and to monitor long term safety when somatropin is administered as an agent in the treatment of CHF.