Three weekly injections (TWI) of low-dose growth hormone (GH) restore low normal circulating IGF-I concentrations and reverse cardiac abnormalities associated with adult onset GH deficiency (GHD)

Patient preferences for growth hormone treatment in Japanese children

BACKGROUND

There are not clear evidence to date evaluating patients' and caregivers' preferences for the recombinant-human growth hormone (r-hGH) injection in children in Japan. This study aimed to quantitatively evaluated the factors driving preferences for daily r-hGH injections among Japanese children with growth hormone deficiency (GHD) or their caregivers and to determine the relative importance of treatment delivery factors.

METHODS

This study was performed among Japanese children with GHD or their caregivers who visited a specialized clinic in Japan as part of their routine care. The participants were asked to complete a web-based discrete choice experiment (DCE) questionnaire.

RESULTS

Choice-based conjoint analysis was used to evaluate the relative importance of the attributes of the choice predictors and determine utility scores for each attribute. Of the 47 respondents who participated in this study, 41 were caregivers who responded on behalf of the patients, the remaining six were patients who completed the DCE themselves. The injection schedule was found to be the most important factor for both patients and caregivers; a once-weekly injection schedule was preferred over a daily injection schedule. Storage and preparation was deemed more important to patients than it was to caregivers, with patients preferring storage at room temperature even if it required additional mixing (reconstitution). Both patients and caregivers showed a clear preference for devices that offered a dose-setting memory.

CONCLUSIONS

A less frequent injection schedule may enhance adherence to r-hGH treatment and expected improve quality of life for GHD patients over the long term.

Adherence, Attitudes and Beliefs of Growth Hormone Deficient Patients - A Questionnaire-based Cohort Study

INTRODUCTION

GHD is a chronic and systemic disease requiring daily replacement of growth hormone (GHRT). Adherence and attitudes of adult GHD patients are not well known. We sought to assess patients' knowledge of growth hormone deficiency (GHD) in association with treatment adherence and attitudes regarding available and upcoming treatment options.

METHODS

We performed a cross-sectional survey with a custom-made questionnaire at a single centre assessing data on demographics, knowledge of GHD, adherence and attitudes towards GHRT.

RESULTS

Of 106 eligible patients actively followed for GHD 70 returned the completed survey (return-rate 66%, 34 m/36 f; age 56±14 years). 46 patients were actively treated, but almost one third (n=24) refused GHRT. 12 patients had participated in clinical trials with LAGH (long-acting growth hormone). Overall, patients with GHRT showed good adherence. Patients refusing GHRT mostly feared side effects and/or had a lack of information/perceived effect. Disease knowledge and level of education were higher in treated than untreated patients (p=0.023/0.017). Only 36% of respondents would initiate treatment with LAGH. Patients with prior LAGH experience and patients with childhood-onset GHD were more likely to adopt LAGH (p=0.048/0.031).

DISCUSSION

Most often, misinformation causes patients to refuse GHRT. Possibly the understanding of their condition and consequences of non-treatment is limited. To improve adherence more focused educational and behavioural strategies may be needed. Willingness to begin a therapy with LAGH was lower than expected (36%). The reasons for reluctance against LAGH need to be elucidated.

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.

More Favorable Metabolic Impact of Three-Times-Weekly versus Daily Growth Hormone Treatment in Naïve GH-Deficient Children

OBJECTIVE

To evaluate whether two different regimens of weekly injections could lead to similar auxological and metabolic effects in children with growth hormone deficiency (GHD).

DESIGN

32 GHD children (25 males, mean age 10.5 ± 2.2 yr) were randomly assigned to receive daily (group A, 16 patients) or TIW (group B, 16 patients) GHT for 12 months.

METHODS

Auxological parameters, insulin-like growth factor-I (IGF-I), glucose and insulin during OGTT, glycosylated hemoglobin (HbA1c), lipid profile, the oral disposition index (DIo), the homeostasis model assessment estimate of insulin resistance (Homa-IR), and the insulin sensitivity index (ISI).

RESULTS

After 12 months, both groups showed a significant and comparable improvement in height (p < 0.001) and IGF-I (p < 0.001). As regards the metabolic parameters, in both groups, we found a significant increase in fasting insulin (p < 0.001 and p = 0.026) and Homa-IR (p < 0.001 and p = 0.019). A significant increase in fasting glucose (p = 0.001) and a decrease in ISI (p < 0.001) and DIo (p = 0.002) were only found in group A.

CONCLUSIONS

The TIW regimen is effective and comparable with the daily regimen in improving auxological parameters and has a more favorable metabolic impact in GHD children. This trial is registered with ClinicalTrials.gov NCT03033121.

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.

GH therapy in adult GH deficiency: a review of treatment schedules and the evidence for low starting doses

Recombinant human GH has been licensed for use in adult patients with GH deficiency (GHD) for over 15 years. Early weight- and surface area-based dosing regimens were effective but resulted in supraphysiological levels of IGF1 and increased incidence of side effects. Current practice has moved towards individualised regimens, starting with low GH doses and gradually titrating the dose according to the level of serum IGF1 to achieve an optimal dose. Here we present the evidence supporting the dosing recommendations of current guidelines and consider factors affecting dose responsiveness and parameters of treatment response. The published data discussed here lend support for the use of low GH dosing regimens in adult GHD. The range of doses defined as 'low dose' in the studies discussed here (∼1-4  mg/week) is in accordance with those recommended in current guidelines and encompasses the dose range recommended by product labels.

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.

Age-related changes in body composition of bovine growth hormone transgenic mice

GH has a significant impact on body composition due to distinct anabolic and catabolic effects on lean and fat mass, respectively. Several studies have assessed body composition in mice expressing a GH transgene. Whereas all studies report enhanced growth of transgenic mice as compared with littermate controls, there are inconsistencies in terms of the relative proportion of lean mass to fat mass in these animals. The purpose of this study was to characterize the accumulation of adipose and lean mass with age and according to gender in a bovine (b) GH transgenic mouse line. Weight and body composition measurements were assessed in male and female bGH mice with corresponding littermate controls in the C57BL/6J genetic background. Body composition measurements began at 6 wk and continued through 1 yr of age. At the conclusion of the study, tissue weights were determined and triglyceride content was quantified in liver and kidney. Although body weights for bGH mice were significantly greater than their corresponding littermate controls at all time points, body composition measurements revealed an unexpected transition midway through analyses. That is, younger bGH mice had relatively more fat mass than nontransgenic littermates, whereas bGH mice became significantly leaner than controls by 4 months in males and 6 months in females. These results reveal the importance in timing and gender when conducting studies related to body composition or lean and fat tissue in GH transgenic mice or in other genetically manipulated mouse strains in which body composition may be impacted.

Role of the GH/IGF-1 axis in lifespan and healthspan: lessons from animal models

Animal models are fundamentally important in our quest to understand the genetic, epigenetic, and environmental factors that contribute to human aging. In comparison to humans, relatively short-lived mammals are useful models as they allow for rapid assessment of both genetic manipulation and environmental intervention as related to longevity. These models also allow for the study of clinically relevant pathologies as a function of aging. Data associated with more distant species offers additional insight and critical consideration of the basic physiological processes and molecular mechanisms that influence lifespan. Consistently, two interventions, caloric restriction and repression of the growth hormone (GH)/insulin-like growth factor-1/insulin axis, have been shown to increase lifespan in both invertebrates and vertebrate animal model systems. Caloric restriction (CR) is a nutrition intervention that robustly extends lifespan whether it is started early or later in life. Likewise, genes involved in the GH/IGF-1 signaling pathways can lengthen lifespan in vertebrates and invertebrates, implying evolutionary conservation of the molecular mechanisms. Specifically, insulin and insulin-like growth factor-1 (IGF-1)-like signaling and its downstream intracellular signaling molecules have been shown to be associated with lifespan in fruit flies and nematodes. More recently, mammalian models with reduced growth hormone (GH) and/or IGF-1 signaling have also been shown to have extended lifespans as compared to control siblings. Importantly, this research has also shown that these genetic alterations can keep the animals healthy and disease-free for longer periods and can alleviate specific age-related pathologies similar to what is observed for CR individuals. Thus, these mutations may not only extend lifespan but may also improve healthspan, the general health and quality of life of an organism as it ages. In this review, we will provide an overview of how the manipulation of the GH/IGF axis influences lifespan, highlight the invertebrate and vertebrate animal models with altered lifespan due to modifications to the GH/IGF-1 signaling cascade or homologous pathways, and discuss the basic phenotypic characteristics and healthspan of these models.

Cardiac effects of growth hormone treatment in chronic heart failure: A meta-analysis

CONTEXT

Experimental studies suggest that GH treatment may improve cardiovascular parameters in chronic heart failure (CHF). However, clinical trials involved small numbers of patients and did not allow a conclusion to be drawn on the effect of this treatment in humans.

OBJECTIVE

We systematically reviewed and analyzed all randomized controlled trials and open studies of sustained GH treatment in CHF.

STUDY SELECTION

Twelve trials were identified in three databases. We conducted a combined analysis of GH effects on cardiovascular parameters using the overall effect size to evaluate significance and computing the weighted mean differences with and without treatment to assess effect size.

DATA SYNTHESIS

GH treatment significantly modified morphological cardiovascular parameters [interventricular septum thickness, +0.55 (sd, 0.43) mm (P < 0.001); posterior wall thickness, +1.01 (0.44) mm (P < 0.01); left ventricle (LV) end-diastolic diameter, -2.02 (1.22) mm (P < 0.01); and LV end-systolic diameter, -5.30 (2.33) mm (P < 0.05)]; LV and systemic hemodynamics [LV end-systolic wall stress, -38.9 (13.3) dynes/cm(2) (P < 0.001); LV ejection fraction, +5.10 (1.74)% (P < 0.05); and systemic vascular resistance, +195.0 (204.5) dyn x sec(-1) x cm(-5) (P < 0.01)]; and functional parameters [New York Heart Association class, -0.97 (0.23) (P < 0.01); exercise duration, +103.7 (37.6) sec (P < 0.001); and maximal oxygen uptake, +2.48 (1.76) ml/kg x min (P < 0.01)]. Subgroup analysis and meta-regression showed significant relationships between the IGF-I response and GH treatment effects.

CONCLUSION

Our meta-analysis suggests that GH treatment improves several relevant cardiovascular parameters in patients with CHF. However, these results must be confirmed by a large randomized placebo-controlled trial on hemodynamic, morphological, and functional parameters during long-term high-dose GH treatment of patients with CHF.

Growth hormone releasing hormone plasmid supplementation, a potential treatment for cancer cachexia, does not increase tumor growth in nude mice

Growth hormone releasing hormone (GHRH) is known to have multiple anabolic effects and immune-stimulatory effects. Previous studies suggest that treatment with anabolic hormones also has the potential to mitigate the deleterious effects of cancer cachexia in animals. We studied the effects of plasmid-mediated GHRH supplementation on tumor growth and the role of antitumor immune cells with two different human tumor cell lines, NCI-H358 human bronchioalveolar carcinoma and MDA-MB-468 human breast adenocarcinoma, subcutaneously implanted in nude mice. GHRH supplementation by delivery of human GHRH from a muscle-specific GHRH expression plasmid did not increase tumor progression in tumor-bearing nude mice. Male animals implanted with the NCI-H358 tumor cell line and treated with the GHRH-expressing plasmid exhibited a 40% decrease in the size of the tumors (P<.02), a 48% increase in white blood cells (P<.025) and a 300% increase in monocyte count (P<.0001), as well as an increase in the frequency of activated CD3+ and CD4+ cells in the tumors, compared to tumors of control animals. No adverse effects were observed in animals that received the GHRH-plasmid treatment. The present study shows that physiological stimulation of the GHRH-GH-IGF-I axis in mice with cancer does not promote tumor growth and may provide a viable treatment for cancer cachexia in humans.

Bridging Regional and Global Perspectives

In recent years, medical practice has evolved towards greater reliance on evidence-based medicine. Societies and reimbursement agencies often publish recommendations for treatment based on literature review and trial data. Despite this, growth hormone (GH) replacement therapy in adults varies substantially from region to region. The reasons for this include differing beliefs in quality of life benefits, the cost-effectiveness of GH and the role of GH in reducing cardiovascular mortality. Reimbursement varies from almost complete take-up in Sweden and Germany, to strict guidelines in the UK, while in some countries GH is not reimbursable for adults with GH deficiency, leaving patients open to the short- and long-term consequences of the condition. Clearly, there is a need for further evidence regarding the overall value of GH replacement. Randomized, controlled trials are the foundation of evidence-based medicine, but long-term treatment is difficult to assess in such trials. Thus, there is an important role for large-scale registries in gathering evidence. For example, the MEGHA (Metabolic Endocrinology and Growth Hormone Assessment) database provides participants with a sub- studies function, allowing them to create and design collective, observational studies to investigate areas of GH medicine that are of particular interest or concern to them and their patients.