Growth hormone: a newcomer in cardiovascular medicine.

Abstract

Time for primary review 31 days. Growth hormone (GH) controls linear growth and a variety of other functions, including nutrient metabolism, skeletal muscle performance, regulation of body composition, and even psychological well-being. The recent finding that GH plays a role in cardiovascular physiology has enlarged GH's spectrum of action even further [1, 2]. GH is essential for cardiac development and for preserving cardiac morphology and performance in adult life. Patients with GH deficiency, particularly those with the congenital form, present with cardiac atrophy and significant impairment of cardiac performance and exercise capacity [3]. Epidemiologic studies have shown that GH deficiency is associated with a high incidence of cardiovascular mortality, mostly due to heart failure [4]. In single case reports, GH deficiency was associated with severe dilated cardiomyopathy, which was unresponsive to conventional therapy but successfully treated with replacement therapy [5–7]. Clinical studies of GH's role in cardiac physiology are intersecting with experimental attempts to treat heart failure with growth factors. Unlike traditional therapeutic approaches that aim at slowing the development of excessive, pathologic cardiac hypertrophy, the new strategy is to favor the induction of ‘physiologic’ forms of hypertrophy. Indeed, both GH and IGF-I have already proven beneficial in several models of experimental heart failure [8–14]. Endeavors to treat human cardiac failure with a growth factor approach are just beginning. In a preliminary study of a small group of selected patients with idiopathic dilated cardiomyopathy, a 3-month treatment with GH improved ventricular geometry, function, and energetics [15]. These data will hopefully encourage the implementation of more robust clinical trials. At this stage of events, it may be useful to examine this novel approach, the underlying rationale, and the studies that generated the idea to approach heart failure with growth factors. ### 2.1 GH deficiency The importance of GH in … * Medicina Interna, via Pansini 5, 80131-Napoli, Italy. Tel.: 81-7473519, fax: 81-7463199, e-mail: sacca@cds.unina.it