Related Experiment Videos
Role of growth hormone in chronic heart failure: therapeutic implications
M Volterrani1, A Giustina, F Manelli
1Division of Cardiology, Salvatore Maugeri Foundation, Medical Center, Gussago, Italy. mvolterrani@fsm.it
Insights
Growth hormone (GH) may impact heart function, but recent studies show mixed results for heart failure treatment. Further research is needed to determine GH
Area of Science:
- Cardiology
- Endocrinology
- Molecular Biology
Background:
- Chronic heart failure (CHF) is a prevalent cardiovascular disorder with significant mortality.
- Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) play roles in cardiac structure and function.
- Existing CHF treatments include diuretics, ACE inhibitors, and beta-blockers.
Purpose of the Study:
- To investigate the potential benefits of GH therapy in patients with heart failure.
- To explore the role of GH and IGF-1 in myocardial function and their modulation by hemodynamic changes.
Main Methods:
- Review of existing literature on GH, IGF-1, and heart failure.
- Analysis of studies involving GH administration in patients with dilated cardiomyopathy.
- Consideration of animal models of heart failure to understand GH/IGF-1 regulation.
Main Results:
- GH and IGF-1 receptors are present in cardiac myocytes, suggesting direct cardiac effects.
- GH deficiency impairs cardiac efficiency, while GH administration improves function in some cases.
- Recent randomized trials showed no significant improvement in cardiac performance with GH in dilated cardiomyopathy, despite increased IGF-1.
Conclusions:
- Acquired GH resistance may occur in severe heart failure, explaining variable treatment responses.
- The efficacy and optimal use of GH in heart failure management require further investigation.
- Current evidence does not definitively establish GH as a standard treatment for heart failure.
Abstract:
Chronic heart failure is a multi-etiological cardiovascular disorder with high prevalence and poor prognosis. Medical treatment of dilated cardiomyopathy is aimed at alleviating heart failure symptoms. Diuretics, angiotensin-converting enzyme (ACE) inhibitors and very recently, beta-blockers have been shown to have favorable effects on symptoms, exercise capacity and mortality. Growth hormone (GH) and insulin-like growth factor (IGF)-1 are involved in several physiological processes such as the control of muscle mass and function, body composition and regulation of nutrient metabolism. The role of GH and IGF-1 as modulators of myocardial structure and function is well established. Receptors for both GH and IGF-1 are expressed by cardiac myocytes; therefore, GH may act directly on the heart or via the induction of local or systemic IGF-1, while IGF-1 may act by endocrine, paracrine or autocrine mechanisms. Patients with acromegaly have an increased propensity to develop ventricular hypertrophy and cardiovascular diseases; impaired cardiac efficiency can also be observed in patients with GH deficiency. Animal models of pressure and volume overload have demonstrated up-regulation of cardiac IGF-1 production and expression of GH and IGF-1 receptors, implying that the local regulation of these factors is influenced by hemodynamic changes. Moreover, experimental studies suggest that GH and IGF-1 have stimulatory effects on myocardial contractility, possibly mediated by changes in intracellular calcium handling. Heart failure is due to ventricular dilation with inadequate wall thickening that leads to impaired cardiac performance; therefore, based on previous evidence we would expect beneficial effects from the use of GH in these patients. Several papers have highlighted the positive influence of GH in the regulation of heart development and performance. In patients with GH deficiency, GH administration dramatically improves cardiac function. In small open studies, acute and chronic GH treatment has demonstrated beneficial effects in patients with heart failure due to ischemic or idiopathic cardiomyopathy. Recently, two randomized, placebo-controlled studies did not show any significant GH-mediated improvement in cardiac performance in patients with dilated cardiomyopathy, despite significant increases in IGF-1. Acquired GH resistance might be an important feature of severe heart failure and explain the diverse responses to GH therapy observed in different patients. Whether GH treatment will finally find a place in the treatment of heart failure, and with which modalities, remains to be established.