Effects of growth hormone replacement therapy on metabolic and cardiac parameters, in adult patients with childhood-onset growth hormone deficiency

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.

Effect of long-term growth hormone replacement on glucose metabolism in adults with growth hormone deficiency: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis was performed to summarize the long-term (more than 6 months) effect of growth hormone (GH) replacement therapy (GHRT) on glucose metabolism among adults growth hormone deficiency (AGHD) patients.

METHODS

We searched MEDLINE, EMBASE and the Cochrane Library databases from inception till March 2020 for relevant studies evaluating the effect of GHRT on glucose metabolism in AGHD patients. Results were stratified into two periods (6-12 months and more than12 months) according to the length of follow-up.

RESULTS

Thirty-three studies including 11 randomized controlled trials (RCTs) and 22 prospective open-label studies (POLs) were included in the meta-analysis. The findings of this meta-analysis showed that GH supplementation with a duration of 6-12 months among adults with growth hormone deficiency (GHD) significantly increased fasting plasma glucose (FPG) (SMD 0.37; 95% CI 0.25 to 0.49; I² = 0%; P < 0.00001), fasting insulin (FI) (SMD 0.2; 95% CI 0.08 to 0.33; I² = 9%; P = 0.001), glycated hemoglobin (HbA1c) (SMD 0.31; 95% CI 0.17 to 0.46; I² = 10%; P < 0.0001) and homeostasis model of assessment-insulin resistance (HOMA-IR) (SMD 0.28; 95% CI 0.08 to 0.47; I² = 13%; P = 0.006). Notably, GH intervention with a duration of more than 12 months showed no significant effect on FI (SMD 0.14; 95% CI - 0.09 to 0.37; I² = 0%; P = 0.24), HbA1c (SMD - 0.02; 95% CI - 0.3 to 0.26; I² = 72%; P = 0.89) and HOMA-IR levels (SMD 0.04; 95% CI - 0.24 to 0.31; I² = 0%; P = 0.80) in adults with GHD. However, FPG levels in AGHD were still significantly increased with more than one year intervention period (SMD 0.41; 95% CI 0.29 to 0.53; I² = 0%; P < 0.00001).

CONCLUSION

Overall, the current meta-analysis demonstrated that GHRT with a shorter duration (6-12 months) led to a deterioration in glucose metabolism including FPG, FI, HbA1c and HOMA-IR in AGHD patients. However, the negative effects of GH therapy on these glucose homeostasis parameters were not seen in longer duration of GHRT, except for FPG.

Characterisation of myocardial structure and function in adult-onset growth hormone deficiency using cardiac magnetic resonance

Growth hormone (GH) can profoundly influence cardiac function. While GH excess causes well-defined cardiac pathology, fewer data are available regarding the more subtle cardiac changes seen in GH deficiency (GHD). This preliminary study uses cardiac magnetic resonance imaging (CMR) to assess myocardial structure and function in GHD. Ten adult-onset GHD patients underwent CMR, before and after 6 and 12 months of GH replacement. They were compared to 10 age-matched healthy controls and sex-matched healthy controls. Left ventricular (LV) mass index (LVMi) increased with 1 year of GH replacement (53.8 vs. 57.0 vs. 57.3 g/m², analysis of variance p = 0.0229). Compared to controls, patients showed a trend towards reduced LVMi at baseline (51.4 vs. 60.0 g/m², p = 0.0615); this difference was lost by 1 year of GH treatment (57.3 vs. 59.9 g/m², p = 0.666). Significantly reduced aortic area was observed in GHD (13.2 vs. 19.0 cm²/m², p = 0.001). This did not change with GH treatment. There were no differences in other LV parameters including end-diastolic volume index (EDVi), end-systolic volume index, stroke volume index (SVi), cardiac index and ejection fraction. There was a trend towards reduced baseline right ventricular (RV)SVi (44.1 vs. 49.1 ml/m², p = 0.0793) and increased RVEDVi over 1 year (70.3 vs. 74.3 vs. 73.8 ml/m², p = 0.062). Two patients demonstrated interstitial expansion, for example with fibrosis, and three myocardial ischaemia as assessed by late gadolinium enhancement and stress perfusion. The increased sensitivity of CMR to subtle cardiac changes demonstrates that adult-onset GHD patients have reduced aortic area and LVMi increases after 1 year of GH treatment. These early data should be studied in larger studies in the future.

Hormone replacement therapy and physical function in healthy older men. Time to talk hormones?

Improving physical function and mobility in a continuously expanding elderly population emerges as a high priority of medicine today. Muscle mass, strength/power, and maximal exercise capacity are major determinants of physical function, and all decline with aging. This contributes to the incidence of frailty and disability observed in older men. Furthermore, it facilitates the accumulation of body fat and development of insulin resistance. Muscle adaptation to exercise is strongly influenced by anabolic endocrine hormones and local load-sensitive autocrine/paracrine growth factors. GH, IGF-I, and testosterone (T) are directly involved in muscle adaptation to exercise because they promote muscle protein synthesis, whereas T and locally expressed IGF-I have been reported to activate muscle stem cells. Although exercise programs improve physical function, in the long-term most older men fail to comply. The GH/IGF-I axis and T levels decline markedly with aging, whereas accumulating evidence supports their indispensable role in maintaining physical function integrity. Several studies have reported that the administration of T improves lean body mass and maximal voluntary strength in healthy older men. On the other hand, most studies have shown that administration of GH alone failed to improve muscle strength despite amelioration of the detrimental somatic changes of aging. Both GH and T are anabolic agents that promote muscle protein synthesis and hypertrophy but work through separate mechanisms, and the combined administration of GH and T, albeit in only a few studies, has resulted in greater efficacy than either hormone alone. Although it is clear that this combined approach is effective, this review concludes that further studies are needed to assess the long-term efficacy and safety of combined hormone replacement therapy in older men before the medical rationale of prescribing hormone replacement therapy for combating the sarcopenia of aging can be established.

Update: Systemic Diseases and the Cardiovascular System (II). The endocrine system and the heart: a review

Normal endocrine function is essential for cardiovascular health. Disorders of the endocrine system, consisting of hormone hyperfunction and hypofunction, have multiple effects on the cardiovascular system. In this review, we discuss the epidemiology, diagnosis, and management of disorders of the pituitary, thyroid, parathyroid, and adrenal glands, with respect to the impact of endocrine dysfunction on the cardiovascular system. We also review the cardiovascular benefits of restoring normal endocrine function.

Update: Systemic Diseases and the Cardiovascular System (II). The endocrine system and the heart: a review

Normal endocrine function is essential for cardiovascular health. Disorders of the endocrine system, consisting of hormone hyperfunction and hypofunction, have multiple effects on the cardiovascular system. In this review, we discuss the epidemiology, diagnosis, and management of disorders of the pituitary, thyroid, parathyroid, and adrenal glands, with respect to the impact of endocrine dysfunction on the cardiovascular system. We also review the cardiovascular benefits of restoring normal endocrine function.

IGF-I replacement therapy in children with congenital IGF-I deficiency (Laron syndrome) maintains heart dimension and function

OBJECTIVE

Untreated patients with congenital growth hormone deficiency (GHD) and IGF-I deficiency are characterized not only by dwarfism but also by acromicria and organomicria, such as the heart. We assessed cardiac dimensions and function in very young patients with Laron syndrome (LS) undergoing IGF-I replacement therapy.

DESIGN

Two to seven echocardiographic measurements were performed during IGF-I replacement therapy on male (n=4) and female (n=4) LS -patients, mean+/-SD age of 7.1+/-3.6 years (range 1.6-11.6 years), weight 16.1+/-9.7 kg, and height 89.9+/-18.5 cm. As aged- and gender-matched controls served 44 healthy children, age: 8.7+/-5.5 years, weight: 36.1+/-22.4 kg, and height: 129.7+/-33.1cm. Data of LS patients were normalized to body surface area and compared to the control group as well as nomograms of normal echocardiographic parameters for this age group.

RESULTS

Left ventricular diastolic and systolic dimensions (LVDD/ LVSD, mm) and LV mass (gr) were significantly smaller in boys and girls with IGF-I treated LS compared with controls while the shortening fraction (%) and intraventricular septum thickness (mm) were similar. When compared with standard values for this age group, all treated LS patients were within 1 standard deviation of the mean.

CONCLUSION

IGF-I therapy of young patients with Laron syndrome maintain LV dimensions and function within the normal range of aged-matched controls.

The effect of growth hormone replacement on exercise capacity in patients with GH deficiency: a metaanalysis

CONTEXT/OBJECTIVES

GH replacement in GH-deficient adults exerts clear effects on body composition, but there is a lack of high-quality evidence concerning its functional effects, which are more clinically important. This metaanalysis was carried out to determine the effects of GH replacement on exercise performance.

DESIGN/METHODS

A Medline search and examination of reference lists of included studies and relevant review articles identified 11 studies with utilizable, robust data, involving a total of 268 patients. All included studies were randomized, double blind, placebo controlled, and of either parallel or crossover design. Information was retrieved in uniform format, with data pertaining to patient numbers, study design, GH dose, age, IGF-I levels, and the exercise variables maximal oxygen uptake and maximal power output recorded. The data were analyzed using a fixed-effects model, using continuous data measured on different scales. A summary effect measure (ds) was derived for the individual exercise parameters, whereas an overall summary effect was derived from the sum of all studies across different variables; 95% confidence intervals were calculated from the weighted variances of individual study effects.

RESULTS

GH replacement was associated with significant improvement with all studies combined (ds=+0.32, 0.08-0.56), for maximal power output (ds=+0.4, 0.06-0.74), and maximal oxygen uptake (ds=+0.34, 0.07-0.62). There was no association between age or GH dose on the degree of improvement.

CONCLUSIONS

There is strong evidence that GH replacement improves exercise performance in GH-deficient patients. This evidence should be considered when decisions are made regarding prescription of GH.

[Growth hormone deficiency in adulthood: how to diagnose and when to treat?]

Adult growth hormone deficiency (AGHD) is a well-established clinical entity with heterogeneous characteristics, in which the main causes are hypothalamus-pituitary tumors and/or their treatment. The diagnosis of ADGH should be considered in patients with a prior history of childhood-onset GH deficiency or a history of organic hypothalamus-pituitary disease. In these patients diagnosis is performed biochemically by provocative tests of GH secretion, once the measurement of the biological markers for GH action:IGF-l and IGFBP-3 levels, can be in the normal range in an important percentage of AGHD patients. The current treatment using an initial low dose of hrGH followed by individualised dose titration adjusted according to serum IGF-1 levels, leads to similar beneficial effects with less incidence of side effects, improved tolerance to treatment and a lower stable GH dose as compared to hrGH replacement therapy based on body weight or body surface area. As some patients might not profit from hrGH therapy, the potential beneficial effects of hrGH replacement therapy should be analyzed on individualized basis. Alternative available therapies with similar efficacy should be taken into consideration. Physical activity may improve body compostion, cardiovascular perfomance and well being in ADGH subjects not submitted to hrGH treatment. An important target of hrGH replacement therapy is its impact on quality of life, leading to social and professional improvement. Epidemiological evidence points to a decreasing life expectancy in ADGH patients but data regarding the impact of hrGH replacement on life expectancy are still lacking.

Therapeutic aspects of growth hormone and insulin-like growth factor-I treatment on visceral fat and insulin sensitivity in adults

Growth hormone (GH) is generally considered to exert anti-insulin actions, whereas insulin-like growth factor I (IGF-I) has insulin-like properties. Paradoxically, GH deficient adults and those with acromegaly are both predisposed to insulin resistance, but one cannot extrapolate from these pathological conditions to determine the normal metabolic roles of GH and IGF-I on glucose homeostasis. High doses of GH treatment have major effects on lipolysis, which plays a crucial role in promoting its anti-insulin effects, whereas IGF-I acts as an insulin sensitizer that does not exert any direct effect on lipolysis or lipogenesis. Under physiological conditions, the insulin-sensitizing effect of IGF-I is only evident after feeding when the bioavailability of circulating IGF-I is increased. In contrast, many studies in GH deficient adults have consistently shown that GH replacement improves the body composition profile although these studies differ considerably in terms of age, the presence or absence of multiple pituitary hormone deficiency, and whether GH deficiency was childhood or adult-onset. However, the improvement in body composition does not necessarily translate into improvements in insulin sensitivity presumably due to the anti-insulin effects of high doses of GH therapy. More recently, we have found that a very low dose GH therapy (0.1 mg/day) improved insulin sensitivity without affecting body composition in GH-deficient adults and in subjects with metabolic syndrome, and we postulate that these effects are mediated by its ability to increase free 'bioavailable' IGF-I without the induction of lipolysis. These results raise the possibility that this low GH dose may play a role in preventing the decline of beta-cell function and the development of type 2 diabetes in these "high risk" subjects.

Applying the Growth Failure in CKD Consensus Conference: evaluation and treatment algorithm in children with chronic kidney disease

Growth failure is a common and significant clinical problem for children with chronic kidney disease (CKD), particularly those with chronic renal insufficiency (CRI). Children with CRI (typically defined by a glomerular filtration rate [GFR] <75 mL/min/1.73 m2) who have growth impairment exhibit a variety of medical and psychological problems in addition to increased mortality. Growth failure in children with CKD is usually multifactorial in etiology, including abnormalities in the growth hormone (GH)-insulin-like growth factor (IGF)-I axis and a variety of nutritional and metabolic concerns characteristic of CKD. Proper management of these factors contributes to better growth in affected children. Although the safety and efficacy of recombinant human GH (rhGH) therapy in promoting growth in children with CKD are well established, recent data indicate that the use of rhGH administration in children with CKD and growth failure remains low. Recently, guidelines were developed by the Consensus Conference for Evaluation and Treatment of Growth Failure in Children with CKD. This paper focuses on the application of these guidelines to children with CKD.

Evaluation and treatment of adult growth hormone deficiency: an Endocrine Society Clinical Practice Guideline

OBJECTIVE

The objective is to provide guidelines for the evaluation and treatment of adults with GH deficiency (GHD).

PARTICIPANTS

The chair of the Task Force was selected by the Clinical Guidelines Subcommittee of The Endocrine Society (TES). The chair selected five other endocrinologists and a medical writer, who were approved by the Council. One closed meeting of the group was held. There was no corporate funding, and members of the group received no remuneration.

EVIDENCE

Only fully published, peer-reviewed literature was reviewed. The Grades of Evidence used are outlined in the Appendix.

CONSENSUS PROCESS

Consensus was achieved through one group meeting and e-mailing of drafts that were written by the group with grammatical/style help from the medical writer. Drafts were reviewed successively by the Clinical Guidelines Subcommittee, the Clinical Affairs Committee, and TES Council, and a version was placed on the TES web site for comments. At each level, the writing group incorporated needed changes.

CONCLUSIONS

GHD can persist from childhood or be newly acquired. Confirmation through stimulation testing is usually required unless there is a proven genetic/structural lesion persistent from childhood. GH therapy offers benefits in body composition, exercise capacity, skeletal integrity, and quality of life measures and is most likely to benefit those patients who have more severe GHD. The risks of GH treatment are low. GH dosing regimens should be individualized. The final decision to treat adults with GHD requires thoughtful clinical judgment with a careful evaluation of the benefits and risks specific to the individual.

Cardiac changes associated with growth hormone therapy among children treated with anthracyclines

OBJECTIVE

The objective was to assess the cardiac effects of growth hormone (GH) therapy. Anthracycline-treated childhood cancer survivors frequently have reduced left ventricular (LV) wall thickness and contractility, and GH therapy may affect these factors.

METHODS

We examined serial cardiac findings for 34 anthracycline-treated childhood cancer survivors with several years of GH therapy and baseline cardiac z scores similar to those of a comparison group (86 similar cancer survivors without GH therapy).

RESULTS

LV contractility was decreased among GH-treated patients before, during, and after GH therapy (-1.08 SD below the age-adjusted population mean before therapy and -1.88 SD 4 years after therapy ceased, with each value depressed below normal). Contractility was higher in the control group than in the GH-treated group, with this difference being nearly significant. The GH-treated children had thinner LV walls before GH therapy (-1.38 SD). Wall thickness increased during GH therapy (from -1.38 SD to -1.09 SD after 3 years of GH therapy), but the effect was lost shortly after GH therapy ended and thickness diminished over time (-1.50 SD at 1 year after therapy and -1.96 SD at 4 years). During GH therapy, the wall thickness for the GH-treated group was greater than that for the control group; however, by 4 years after therapy, there was no difference between the GH-treated group and the control group.

CONCLUSIONS

GH therapy among anthracycline-treated survivors of childhood cancer increased LV wall thickness, but the effect was lost after therapy was discontinued. The therapy did not affect the progressive LV dysfunction.

Effects of growth hormone on anthropometric measurements and cardiac function in children with thermal injury

Severe burn injuries are associated with growth delays a persistent hypermetabolic response and severe muscle catabolism and wasting. Growth hormone (GH), a potent anabolic agent and salutary modulator of post-traumatic metabolic responses has been shown to decrease muscle wasting, improve net protein synthesis and attenuate growth delays in burned children. In non-burned populations, GH has recently been shown to be of benefit in enhancing cardiac performance and improving cardiac contractility and efficiency. Yet, whether administration of GH will induce similar improvements in cardiac function in severely burned children is presently unknown. We therefore, investigated whether the administration of GH initiated upon hospital discharge (95% healed) and continued for 1-year post-burn would improve resting cardiac function in burned children. Severely burned children were randomized to receive either saline placebo (n = 37) or 0.05 mg/kg per day of GH (n = 39) from discharge until 12-month post-burn. Outcome variables included height, weight, lean body mass, resting energy expenditure, cardiac index, stroke-volume index, heart rate and left ventricular ejection fraction.

RESULTS

height, weight, lean body mass and ejection fraction showed a significant increase with GH. Our results indicate that severely burned children treated with long-term GH show a significant improvement in left ventricular ejection fraction.