Growth hormone, vascular reactivity, and heart failure

Recombinant bovine growth hormone-induced reduction of atrial natriuretic peptide is associated with improved left ventricular contractility and reverse remodeling in cardiomyopathic UM-X7.1 hamsters with congestive heart failure

OBJECTIVE

To assess the effect of short-term treatment with GH on left ventricular contractility and remodeling, after the development of heart failure in cardiomyopathic hamsters (CMH).

DESIGN

Two groups of 200-day-old UM-X7.1 CMH received daily subcutaneous injections of recombinant bovine (rb) GH (1mg/kg/day) or 0.9% NaCl for 40 days. Golden Syrian hamsters (GSH) were used as controls. At 240-day-old, the hamsters were randomly subjected to (i) assessment of left ventricular systolic function in a Langendorff perfused mode followed by the determination of the passive diastolic pressure-volume relationship and morphometric measurements; (ii) assessment of left ventricular mRNA expression of genes belonging to the fetal gene program including atrial (ANP) and brain (BNP) natriuretic peptides and cardiac myosin heavy chain isoforms and of the circulating levels of the natriuretic peptides.

RESULTS

Hearts from CMH were hypertrophied and dilated (p<0.05) compared to hearts from GSH, along with a approximately 10-fold increase in the circulating ANP and BNP levels. Left ventricular BNP and ANP mRNAs were elevated by 2- and 3-fold, respectively, compared to GSH. rbGH reduced both ANP mRNA and ANP circulating levels by 34% (p<0.01) but did not significantly modulate BNP levels. This effect was associated with a preserved systolic function and reverse remodeling as assessed by a leftward shift of the passive diastolic pressure-volume relationship indicating reduced ventricular dilatation.

CONCLUSIONS

The data show that a short-term administration of GH in the terminal phase of the disease confers cardioprotection by attenuating systolic dysfunction and by inducing beneficial reverse remodeling.

A case and review of acromegaly-induced cardiomyopathy and the relationship between growth hormone and heart failure: cause or cure or neither or both?

Growth hormone plays an integral role in the development and maintenance of structure and function of the heart. Specific involvement of the heart in acromegaly is termed acromegalic cardiomyopathy, manifested as concentric left ventricular hypertrophy and diastolic dys-function. Left untreated, it ultimately progresses to systolic heart failure. Heart failure from acromegalic cardiomyopathy is one of the most common causes of death in acromegaly. Current treatment options include different approaches to lower elevated growth hormone levels with improvement in symptoms, exercise tolerance, and echocardiographic improvement in regression of left ventricular hypertrophy and indices of diastolic dysfunction. On the other hand, growth hormone is essential for cardiac growth and function and exerts beneficial and protective effects on the cardiovascular system. Its potential role as adjunctive therapy in the treatment of heart failure as derived from experimental studies and clinical trials is discussed.

Use of ACE inhibitors is associated with elevated levels of IGFBP-3 among hypertensive older adults: results from the IlSIRENTE study

OBJECTIVE

Several studies in vitro or in rodent models have suggested a potential relationship between angiotensin-converting enzyme (ACE) inhibition and the insulin-like growth factor 1 (IGF-1) axis. However, this relationship has only rarely been investigated in humans. The aim of the present cross-sectional study was to assess the association of ACE inhibitors with free IGF-1 and IGFBP-3 in the blood of older hypertensive adults.

METHODS

Data are from the baseline evaluation of the IlSIRENTE study, which enrolled 364 subjects aged 80 or older. For the present study we selected a subpopulation of 264 hypertensive participants without congestive heart failure. Free IGF-1 and IGFBP-3 in the blood were measured by a radioimmunoassay method. Analyses of covariance were performed to evaluate the differences in free IGF-1 and IGFBP-3 levels according to the use of ACE inhibitors.

RESULTS

The mean age of participants was 85.7 years (SD: 4.9), 170 (64%) were women and 123 (47%) were using an ACE inhibitor. Following adjustment for potential confounders, the concentration of free IGF-1 was slightly, but not significantly higher among ACE inhibitor users than among non-users (0.74 vs. 0.65 ng/mL; p=0.20). In contrast, ACE inhibitor users had a significantly higher IGFBP-3 serum levels than non-users (4821 vs. 4330 ng/mL; p=0.005). In addition, the concentration of IGFBP-3 was significantly higher among ACE inhibitors users than among non-users of antihypertensive drugs (p=0.02) and users of other antihypertensive drugs (p=0.01).

CONCLUSION

Among hypertensive older adults, ACE inhibitors use is associated with higher IGFBP-3 levels.