EDITOR--In their editorial Smith et al review the literature relating high circulating concentrations of insulin-like growth factor-I to the risk of developing certain malignancies. They warn of the dangers of the use of exogenous insulin-like growth factor-I by athletes, in whom the additional lifetime risk of developing an associated cancer may be increased. Towards the end of life, however, maybe the anabolic anti-apoptotic properties of insulinlike growth factor-I be should be considered in a different light.
Cardiac cachexia is a devastating phenotype of chronic heart failure associated with high morbidity and reduced survival. High concentrations of growth hormone and inappropriately low concentrations of insulin-like growth factor-I are recognised features of this syndrome and suggest that a state of growth hormone resistance pervades. The finding that skeletal muscle bulk also correlates inversely with concentrations of insulin-like growth factor-I hints at a pathophysiological link between these findings. Furthermore, in dogs with heart failure, which have a high incidence of cachexia, those with raised concentrations of circulating insulin-like growth factor-I actually show an advantage in survival. These findings perhaps reflect the possible advantages of higher concentrations of insulin-like growth factor-I in chronic disease alluded to by Smith et al.
In patients with chronic wasting diseases approaching the end of life, when the theoretical risk of treatment associated malignancy can reasonably be ignored, higher concentrations of insulin-like growth factor-I may be beneficial. There is, therefore, a valid argument for the use of exogenous, anabolic, anti-apoptotic compounds, such as insulin-like growth factor-I, in catabolic states where mortality is high and even short term benefits are elusive. Such new approaches to the treatment of a crippling syndrome such as cardiac cachexia would be most welcomed.
Aidan Bolger research fellow email@example.com
Wolfram Doehner research fellow
Stefan D Anker research associate Department of Clinical Cardiology, National Heart and Lung Institute, London SW3 6LY
 Smith GD, Gunnell D, Holly J. Cancer and insulin-like growth factor-I. BMJ 2000;321:847-8. (7 October.)
 Anker SD, Ponikowski P, Varney S, Chua TP, Clark AL, Webb-Peploe KM, et al. Wasting as independent risk factor for mortality in chronic heart failure. Lancet 1997;349:1050-3.
 Anker SD, Chua TP, Ponikowski P, Harrington D, Swan JW, Kox WJ, et al. Hormonal changes and catabolic/anabolic imbalance in chronic heart failure and their importance for cardiac cachexia. Circulation 1997;96:526-34.
 Niebauer J, Pflaum C-D, Clark AL, Strasburger CJ, Hooper J, Poole-Wilson PA, et al. Deficient insulin-like growth factor-1 in chronic heart failure predicts altered body composition, cytokine and neurohormonal activation. JAm Coil Cardiol 1998;32:393-7.
 Freeman LM, Rush JE, Kehayias JJ, Ross JN Jr, Meydani SN, Brown DJ, et al. Nutritional alterations and the effect of fish oil supplementation in dogs with heart failure. Intern Med 1998;12:440-8.
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