The influence of growth hormone (GH) therapy on cardiac performance in patients with childhood onset GH deficiency

Electrocardiographic Findings in Children With Growth Hormone Deficiency

Introduction It has been shown that cardiac functions begin to deteriorate in growth hormone (GH) deficiency even in childhood. However, little is known about how GH deficiency affects arrhythmogenesis. The aim of this study was to evaluate the parameters of P wave dispersion (Pd), QT dispersion (QTd), corrected QT (QTc) dispersion (QTcd), T wave peak-to-end (Tp-e) interval, Tp-e/QT ratio, and Tp-e/QTc ratio in children with GH deficiency. This study also aimed to evaluate the relationship of these parameters with insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3). Method In the study, records of children diagnosed with GH deficiency in Adana City Training and Research Hospital Pediatric Endocrine Outpatient Clinic between September 2021 and December 2022 were retrospectively reviewed. The control group consisted of children in the same age group who applied to the Emergency Outpatient Clinic with a complaint of chest pain and no pathological finding was detected. The electrocardiograms (ECGs) of all patients were retrospectively evaluated. Results There were a total of 82 children in the study, 41 of whom were diagnosed with GH deficiency and 41 in the healthy control group. The age and male/female ratio of children with GH deficiency were similar to those in the control group (p>0.05). There were 27 (66%) children with complete GH deficiency and 14 (34%) children with partial GH deficiency. P wave dispersion was similar in both GH-deficient children and control group children. It was also similar in children with complete and partial GH deficiency (p>0.05). QT and QTc dispersions were found to be increased in children with GH deficiency, although not statistically significant, compared to the control group (p>0.05). Tp-e interval, Tp-e/QTmax (longest QT interval), and Tp-e/QTcmax (longest QTc interval) ratios were increased in children with GH deficiency compared to the control group (p=0.001, p=0.003, and p=0.001, respectively). QT and QTc dispersion, Tp-e interval, Tp-e/QTmax, and Tp-e/QTcmax ratios were found to be increased in children with complete GH deficiency compared to children with partial GH deficiency, but the difference was not significant (p>0.05). No correlation was found between these ECG parameters and IGF-1, IGFBP-3, and peak GH levels after stimulation tests (p>0.05). Conclusion We found in our study that the Tp-e interval was longer and Tp-e/QT and Tp-e/QTc ratios were increased in children with GH deficiency. These results suggest that the risk of ventricular arrhythmias in children with GH deficiency may start to increase from childhood. However, further prospective studies are needed to confirm our results.

Evaluation of cardiac structure, exercise capacity and electrocardiography parameters in children with partial and complete growth hormone deficiency and their changes with short term growth hormone replacement therapy

PURPOSE

To evaluate cardiac structure, exercise capacity and electrocardiography (ECG) parameters of children with complete and partial growth hormone (GH) deficiency (GHD) and the effect of 12 months GH treatment on these.

METHODS

M-mode echocardiography, ECG and exercise test expressed as metabolic equivalent (MET) were performed in children with GHD, aged 9-14 years, divided into those with a peak GH response < 7 µg/L (complete GHD; n = 30) and 7-10 µg/L (partial GHD; n = 17) after two GH stimulation tests, at baseline and 12 months after GH initiation. Forty-eight healthy peers underwent the same tests once.

RESULTS

Left ventricular mass (LVM) was significantly lower before treatment in both groups with GHD compared to healthy peers (p = 0.015 and p = 0.032) but LVM in the GHD groups was similar to controls after 12 months of treatment. The increase in LVM in the complete GHD group was significant (p = 0.044). LVM index was significantly reduced with treatment in children with partial GHD (p = 0.035). Max METs, VO_2max and exercise duration were significantly increased in children with complete GHD after treatment (p = 0.022, p = 0.015 and p = 0.002, respectively). Significant changes in P wave and QTc dispersion on ECG between groups were within physiological limits.

CONCLUSION

This study showed that children with both partial and complete GHD had smaller cardiac structures and less exercise capacity compared to their healthy peers prior to GH treatment but this improved with 12 months of treatment. The cardiac trophic effect of GH, as well as the effect of increasing exercise capacity, is greater in those with complete GHD than in those with partial GHD.

Metabolic Profile and Echocardiographic Evaluation in Adults with Growth Hormone Deficiency

Adult growth hormone deficiency (AGHD) is associated with increased cardiovascular risks. The primary endpoint of this retrospective cohort study was to compare metabolic profile and echocardiographic parameters in childhood-onset (CO) and adulthood-onset (AO) AGHD patients. 26 patients with CO AGHD (19 males, 26.8±8.5 years) and 41 patients with AO AGHD (23 males, 35.1±6.8 years) were included. The standard deviation score of insulin-like growth factor-1 (IGF-1 SDS), metabolic profile, liver sonography and echocardiographic parameters were compared. The IGF-1 SDS were significantly lower in CO AGHD patients (p<0.05). AO AGHD patients showed much profound glycolipid aberrations, elevated C-reactive protein levels (p=0.012), and proportionally higher prevalence of non-alcoholic fatty liver disease (95.2% vs.8.3%, p<0.001). In all subjects, IGF-1 SDS was negatively related to low-density lipoprotein cholesterol, and positively related to total cholesterol and lipoprotein a (Lpa). There were significant differences between the two group with regard to the correlations between IGF-1 SDS and high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, LPa, uric acid and creatinine (all p for interaction<0.05). CO AGHD patients exhibited smaller heart, but similar ventricular ejection fraction compared to AO AGHD patients. AGHD may be a group of heterogenous entity based on the onset ages of disease. AO patients had prominent metabolic disorders, while CO patients had smaller heart but similar cardiac performance. Whether growth hormone replacement therapy will equally benefit both CO and AO AGHD patients needs further investigations.

Cardiac functions in children with growth hormone deficiency: Effects of one year of GH replacement therapy

INTRODUCTION

Children with Growth Hormone deficiency (GHD) are prone to heart dysfunction and, if left untreated, will result in marked cardiac dysfunction in adulthood. The aim was to evaluate the effect of GHD and growth hormone (GH) therapy on cardiac structure in children and adolescents, and to investigate the role of insulin like growth factor-1 (IGF-1) in this.

METHODS

M-mode, pulse-wave Doppler echocardiography and tissue Doppler imaging (TDI) were performed in 49 children with GHD who were divided into those with a peak GH response < 7 μg/L and 7-10 μg/L after two GH stimulation tests, aged 8-16 years at baseline and at six and 12 months after GH initiation, and 49 healthy peers. IGF-1 concentration was measured.

RESULTS

Although the left ventricular end diastolic and systolic diameters in both GH deficient groups were significantly lower than controls (p < 0.01), both diameters increased significantly with one year of treatment and achieved normal values (p > 0.05). Using TDI in both two patients group revealed increased E/A, prolonged isovolumic relaxation time, shortened ejection time, and a significant increase in myocardial performance index compared to controls (p < 0.001). Significant improvement was observed in these parameters from the sixth month of GH treatment (p < 0.001), this improvement does not match parameters measured in healthy peers, even after one year of treatment in both patients group. (p < 0.001). No correlation was found between IGF-1 concentration and any echocardiographic parameter.

CONCLUSION

Echocardiographic parameters were similar in children with a GH peak < 7 μg/L and 7-10 μg/L. In TDI, both systolic and diastolic function was impaired in GHD children compared to controls. These parameters improved after one year of GH therapy but did not recover to healthy control levels.

Effects of human recombinant growth hormone on exercise capacity, cardiac structure, and cardiac function in patients with adult-onset growth hormone deficiency

Objective

Epidemiological studies suggest that adult-onset growth hormone deficiency (AGHD) might increase the risk of death from cardiovascular causes.

Methods

This was a 6-month double-blind, placebo-controlled, randomised, cross-over trial followed by a 6-month open-label phase. Seventeen patients with AGHD received either recombinant human growth hormone (rGH) (0.4 mg injection daily) or placebo for 12 weeks, underwent washout for 2 weeks, and were then crossed over to the alternative treatment for a further 12 weeks. Cardiac magnetic resonance imaging, echocardiography, and cardiopulmonary exercise testing were performed at baseline, 12 weeks, 26 weeks, and the end of the open phase (12 months). The results were compared with those of 16 age- and sex-matched control subjects.

Results

At baseline, patients with AGHD had a significantly higher systolic blood pressure, ejection fraction, and left ventricular mass than the control group, even when corrected for body surface area. Treatment with rGH normalised the insulin-like growth factor 1 concentration without an effect on exercise capacity, cardiac structure, or cardiac function.

Conclusion

Administration of rGH therapy for 6 to 9 months failed to normalise the functional and structural cardiac differences observed in patients with AGHD when compared with a control group.

Extrapituitary growth hormone synthesis in humans

The gene for pituitary growth hormone (GH-N) in man belongs to a multigene locus located at chromosome 17q24.2, which also harbors four additional genes: one for a placental variant of GH-N (named GH-V) and three of chorionic somatommamotropin (CSH) type. Their tandem arrangement from 5' to 3' is: GH-N, CSH-L, CSH-1, GH-V and CSH-2. GH-N is mainly expressed in the pituitary from birth throughout life, while the remaining genes are expressed in the placenta of pregnant women. Pituitary somatotrophs secrete GH into the bloodstream to act at receptor sites in most tissues. GH participates in the regulation of several complex physiological processes, including growth and metabolism. Recently, the presence of GH has been described in several extrapituitary sites, such as neural, ocular, reproductive, immune, cardiovascular, muscular, dermal and skeletal tissues. It has been proposed that GH has an autocrine action in these tissues. While the body of evidence for its presence is constantly growing, research of its possible function and implications lag behind. In this review we highlight the evidence of extrapituitary synthesis of GH in humans.

Cranial irradiation as an additional risk factor for anthracycline cardiotoxicity in childhood cancer survivors: an analysis from the cardiac risk factors in childhood cancer survivors study

Anthracycline-treated childhood cancer survivors experience cardiac damage that results in decreased left ventricular (LV) mass, leading to increased LV wall stress, which underlies their greater risk of cardiomyopathy. Many of these survivors also are at risk of growth hormone (GH) abnormalities from cranial irradiation exposure, although it is unknown whether such exposure is associated with cardiotoxicity. Echocardiograms and insulin-like growth factor-1 (IGF-1), a marker of GH, were measured in 130 anthracycline-treated childhood cancer survivors, 59 of whom had been exposed to cranial irradiation, a mean 10 years after their cancer diagnosis. Echocardiographic parameters and IGF-1 were standardized relative to age or body surface area using data from sibling control subjects and expressed as the percentage difference from normal values. The results showed that after adjustment for other risk factors, survivors exposed to cranial irradiation had an additional 12 % decrease in LV mass compared with unexposed survivors (P < 0.01) and an additional 3.6 % decrease in LV dimension (P = 0.03). Survivors exposed to cranial irradiation also had a 30.8 % decrease in IGF-1 relative to normal values, which was greater than the 10.5 % decrease in unexposed survivors (P < 0.01). The above findings led us to conclude that in anthracycline-treated childhood cancer survivors a mean 10 years after their diagnosis, those with cranial irradiation exposure had significantly greater decreases in LV mass and dimension. Because cranial irradiation also was associated with decreased IGF-1, it is possible that GH deficiencies mediated this effect, suggesting that GH replacement therapy may help to prevent the development of cardiotoxicity.

Panhypopituitarism presenting as life-threatening heart failure caused by an inherited microdeletion in 1q25 including LHX4

Clinical presentation of hypopituitarism in the neonate may be variable, ranging from absent to severe nonspecific symptoms and may be life-threatening in patients with adrenocorticotropic hormone deficiency. The LIM homeobox gene 4 (LHX4) transcription factor regulates early embryonic development of the anterior pituitary gland. Autosomal dominant mutations in LHX4 cause congenital hypopituitarism with variable combined pituitary hormone deficiency (CPHD). We report on a neonate with unexplained heart failure and minor physical anomalies, suggesting a midline defect. She was diagnosed with complete CPHD. Cardiac function was rescued by replacement with hydrocortisone and thyroxine; hypoglycaemia stopped under growth hormone therapy. Magnetic resonance imaging revealed a dysgenetic pituitary gland suggesting an early developmental defect. Array comparative genomic hybridization showed a maternally inherited 1.5-megabase microdeletion in 1q25.2q25.3, including the LHX4 gene. Haploinsufficiency of LHX4 likely explains the predominant pituitary phenotype in the proposita and we suggest variable intrafamilial penetrance of the inherited microdeletion. To the best of our knowledge, we are the first to report on heart failure as a rare nonspecific symptom of treatable CPHD in the newborn. Variably penetrant pituitary insufficiency, including this severe and atypical presentation, can be correlated with LHX4 insufficiency and highlights the role of LHX4 for pituitary development.

Early-onset growth hormone deficiency results in diastolic dysfunction in adult-life and is prevented by growth hormone supplementation

OBJECTIVE

The primary goal of growth hormone (GH) replacement is to promote linear growth in children with growth hormone deficiency (GHD). GH and insulin-like growth factor-1 (IGF-1) are also known to have roles in cardiac development and as modulators of myocardial structure and function in the adult heart. However, little is known about cardiac diastolic function in young adults with childhood onset GH deficiency in which GH treatment was discontinued following puberty. The aim of the study was to evaluate the effects of long standing GHD and peri-pubertal or continuous GH replacement therapy on diastolic function in the adult dwarf rat.

DESIGN

The dwarf rat, which possesses a mutation in a transcription factor necessary for development of the somatotroph, does not exhibit the normal peri-pubertal rise in GH around day 28 and was used to model childhood or early-onset GHD (EOGHD). In another group of male dwarfs, GH replacement therapy was initiated at 4 weeks of age when GH pulsatility normally begins. Ten weeks after initiation of injections, GH-treated dwarf rats were divided into 2 groups; continued treatment with GH for 12 weeks (GH-replete) or treatment with saline for 12 weeks. This latter group models GH supplementation during adolescence with GHD beginning in adulthood (adult-onset GHD; AOGHD). Saline-treated heterozygous (HZ) rats were used as age-matched controls. At 26 weeks of age, cardiac function was assessed using invasive or noninvasive (conventional and tissue Doppler) indices of myocardial contractility and lusitropy.

RESULTS

Systolic function, as determined by echocardiography, was similar among groups. Compared with HZ rats and GH-replete dwarfs, the EOGHD group exhibited significant reductions in myocardial relaxation and increases in left ventricular filling pressure, indicative of moderate diastolic dysfunction. This was further associated with a decrease in the cardiac content of sarcoplasmic reticulum Ca(2+) ATPase (SERCA2), one of the important cardiac calcium regulatory proteins. Dwarfs supplemented with GH during the peri-adolescence stage, but not beyond (AOGHD), exhibited a subtle prolongation in the deceleration time to early filling. In contrast, continual GH replacement preserved diastolic function such that the cardiac phenotype of the GH-replete dwarfs resembled that of their age-matched HZ counterpart.

DISCUSSION

Our data indicate that GHD during adolescence leads to overt diastolic dysfunction in early adulthood and this is prevented by continual GH replacement therapy. Since discontinuation of GH replacement following adolescence only mitigated the lusitropic deficits that were observed in untreated dwarfs, GH treatment into adulthood could be beneficial.

Cardiac function in growth hormone deficient patients before and after 1 year with replacement therapy: a magnetic resonance imaging study

Assessed by conventional echocardiography the influence of growth hormone deficiency (GHD) and effects of replacement therapy on left ventricle (LV) function and mass (LVM) have shown inconsistent results. We aimed to evaluate cardiac function before and during replacement therapy employing the gold standard method cardiac magnetic resonance imaging (CMRI) and measurements of circulating levels of B-type natriuretic peptides. Sixteen patients (8 males and 8 females, mean age 49 years (range 18-75)) with severe GHD and 16 matched control subjects were included. CMRI was performed at baseline and after 1 year of GH replacement therapy. IGF-I, B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) were measured after 0, 1, 2, 3, 6 and 12 months of treatment. IGF-I Z-score increased from (median (IQR)) -2.3 (-3.8 to -1.4) to 0.5 (-0.3 to 1.7). LVM index (LVMI), ejection fraction (range 63-80%), cardiac output index and levels of BNP and NT-proBNP were similar at baseline in patients compared to controls (P-values from 0.09 to 0.37). The patients had significantly smaller LV end-diastolic volume index (P = 0.032) and end-systolic volume index (P = 0.038). No significant change in LV systolic function or LVM occurred during 1 year of GH treatment. BNP levels were unchanged (P = 0.88), whereas NT-proBNP tended to decrease (P = 0.052). Assessed by the highly sensitive and precise CMRI method, untreated GHD was not associated with impaired systolic function or reduced LVMI and 1 year of GH replacement using physiological doses did not influence cardiac mass or function.

Effects of 5 years of growth hormone (GH) replacement therapy on cardiac parameters and physical performance in adults with GH deficiency

The purpose of this study was to evaluate the effects of 5 years of GH substitution on cardiac structure and function, physical work capacity and blood pressure levels in adults with GH deficiency (GHD). Fourteen patients were clinically assessed every 3 months for 5 years. Transthoracic echocardiography and exercise test were performed at baseline, 24, 48 and 60 months. Blood pressure (BP) was measured by means of ambulatory monitoring of blood pressure at baseline, 6, 12, 24 and 60 months. Left ventricular mass and its index increased progressively during the 5 years of GH substitution (P = 0.008 and 0.007, respectively). There were no significant changes in all others cardiac parameters evaluated. It was observed a significant improve in functional capacity (P < 0.001) and maximal oxygen uptake (P = 0.006) during the treatment. Diurnal systolic BP increased by 15 mmHg (P = 0.024) and diurnal diastolic BP by 4.5 mmHg (P = 0.037). There was no change in dirnal systolic pressure load but a considerable but non-statistically significant reduction in diurnal diastolic pressure load was observed during the study. During the night diastolic BP increased by 4 mmHg (P = 0.012) despite a substantial but non-statistically significant reduction in diastolic pressure load. We observed an increase in the proportion of persons with a non-physiological nocturnal fall (non-dippers) throughout the study (from 36.4% at baseline to 54.6% after 60 months of therapy). We concluded that 5 years of GH replacement promoted positive effects on exercise capacity and maximum oxygen uptake in spite of a modest increase in BP levels and left ventricular mass. Continuous monitoring is mandatory to arrive at further conclusions concerning the effects of GH substitution in adults on cardiovascular parameters with respect to possible unfavorable long term effects.

Effect of growth hormone on cardiac contractility in patients with adult onset growth hormone deficiency

This study was conducted to investigate the effect of growth hormone (GH) replacement on cardiac function assessed by standard or tissue Doppler echocardiography in GH deficiency. Ten patients (mean age 47+/-14 years) received GH at a dose of 1.0 IU/day (6 times/week). After 6 months of GH replacement, GH substitution was discontinued. Echocardiography was performed at baseline, after 6 months of therapy, and 1 year after the withdrawal of GH replacement. All parameters were compared with those from 11 healthy controls matched for age, gender, and left ventricular (LV) mass index. After GH replacement, LV ejection fractions were nonsignificantly increased. However, fractional shortening, LV dimensions, and LV volumes did not change. Compared with controls, peak strain (-18.9+/-4.8% vs -15.7+/-6.9%, p<0.01) and strain rate (-1.3+/-0.4/s vs -1.0+/-0.5/s, p<0.01) at baseline were significantly decreased in patients with GH deficiency. Strain and strain rate increased significantly after 6 months of replacement but returned to baseline levels after 12 months off therapy. In conclusion, GH replacement in adult-onset GH deficiency demonstrated beneficial effects on cardiac contractility assessed by strain and strain rate, but these parameters returned to baseline levels after the withdrawal of GH. Strain and strain rate can be used to evaluate subtle changes in myocardium after GH replacement.