Growth hormone therapy in adults and children

Approach to the Peripubertal Patient With Short Stature

CONTEXT

The assessment and treatment of children with growth retardation is increasingly complex, and due to availability of targeted genetic sequencing, an ever-expanding number of conditions impeding growth are being identified. Among endocrine-related etiologies of short stature amenable to hormonal treatment, defects in the growth hormone (GH)-insulin-like growth factor I axis remain pre-eminent, with a multiplicity of disorders causing decreased secretion or insensitivity to GH action. Sex steroids in puberty increase epiphyseal senescence and eventual growth plate closure. This is mediated mostly via estrogen receptor (ER)α in males and females, effects that can greatly limit time available for growth.

EVIDENCE ACQUISITION

Extensive literature review through PubMed and other search engines.

EVIDENCE SYNTHESIS

Therapeutic strategies to be considered in peripubertal and pubertal children with disordered growth are here discussed, including daily and weekly GH, low-dose sex steroids, gonadotropin hormone releasing hormone (GnRH) analogues in combination with GH, aromatase inhibitors (AIs) alone and in combination with GH in boys. When used for at least 2 to 3 years, GnRH analogues combined with GH can result in meaningful increases in height. AIs used with GH permit puberty to progress in boys without hindrance, selectively decreasing estrogen, and resulting in taller height. With more than 20 years of cumulative experience in clinical use of these medications, we discuss the safety profile of these treatments.

CONCLUSION

The approach of growth retardation in the peripubertal and pubertal years must consider the sex steroid milieu and the tempo of bone acceleration. Treatment of affected children in this period must be individualized.

Evaluation of the safety and efficacy of biosimilar recombinant growth hormone in children with growth hormone deficiency: non-inferiority, randomized, parallel, multicentric and Phase III trial

OBJECTIVES

This study is designed in order to compare the efficacy and safety of recombinant human growth hormone (rhGH) with the reference brand.

METHODS

According to the inclusion criteria, 85 people in 13 Iranian centers were randomly selected to receive biosimilar Somatropin (Somatin®) (44 people) and reference Somatropin (Norditropin®) (41 people) at a dose of 35 µg/kg/d, seven days/week for 12 months. The primary outcomes included height velocity (HV) was measured during 12 months of treatment.

RESULTS

The two intervention groups' Height changes were similar. The mean HV was 10.96 cm/year in the biosimilar group and 10.05 cm/year in the reference groups after 12 months. Estimates of the lower bounds of 95% CI for mean height differences in the biosimilar intervention group compared to the reference intervention group did not exceed the 2 cm margin. Therefore, the non-inferiority of biosimilar intervention compared to the brand product is verified. Common ADRs in both groups were nausea in two patients (2.4%), diarrhea in two patients (2.4%), increased body temperature in one patient (1.2%), and headache in one patient (1.2%).

CONCLUSIONS

The finding of this study indicated that Somatin® and Norditropin® have comparable efficacy and safety profiles.

CLINICAL TRIAL REGISTRATION

www.IRCT.irIRCT20171122037571N1.

Growth hormone receptor agonists and antagonists: From protein expression and purification to long-acting formulations

Recombinant human growth hormone (rhGH) and GH receptor antagonists (GHAs) are used clinically to treat a range of disorders associated with GH deficiency or hypersecretion, respectively. However, these biotherapeutics can be difficult and expensive to manufacture with multiple challenges from recombinant protein generation through to the development of long-acting formulations required to improve the circulating half-life of the drug. In this review, we summarize methodologies and approaches used for making and purifying recombinant GH and GHA proteins, and strategies to improve pharmacokinetic and pharmacodynamic properties, including PEGylation and fusion proteins. Therapeutics that are in clinical use or are currently under development are also discussed.

Somapacitan in children born small for gestational age: a multi-centre, open-label, controlled phase 2 study

OBJECTIVE

Investigate efficacy, safety, and tolerability of 3 once-weekly somapacitan doses compared with daily growth hormone (GH) administration in short children born small for gestational age (SGA).

DESIGN

Randomised, multi-centre, open-label, controlled phase 2 study comprising a 26-week main phase and a 4-year extension (NCT03878446). The study was conducted at 38 sites across 12 countries. 26-week main phase results are presented here.Sixty-two GH treatment-naïve, prepubertal short children born SGA were randomised and exposed; 61 completed the main phase. Three somapacitan doses (0.16 [n = 12], 0.20 [n = 13], 0.24 [n = 12] mg/kg/week) and 2 daily GH doses (0.035 [n = 12], 0.067 [n = 13] mg/kg/day) were administered subcutaneously.

RESULTS

After 26 weeks of treatment, the estimated mean annualised height velocity (HV) was 8.9, 11.0, and 11.3 cm/year for somapacitan 0.16, 0.20, and 0.24 mg/kg/week, respectively, compared to 10.3 and 11.9 cm/year for daily GH 0.035 and 0.067 mg/kg/day. Changes from baseline in HV standard deviation score (SDS), height SDS, and insulin-like growth factor I (IGF-I) SDS showed similar dose-dependent responses. Exposure-response modelling indicated the greatest efficacy correlated with the highest somapacitan exposure. Similar safety and tolerability were demonstrated for all weekly somapacitan and daily GH doses.

CONCLUSIONS

Based on the totality of data on improvements in height-based parameters combined with exposure-response analyses, somapacitan 0.24 mg/kg/week appears most efficacious, providing similar efficacy, safety, and tolerability as daily GH 0.067 mg/kg/day in short children born SGA after 26 weeks of treatment.

Experience of switching from a daily to a less frequent administration of injection treatments

BACKGROUND

Daily injections of recombinant human growth hormone are the standard of care to treat growth failure due to pediatric growth hormone deficiency (GHD). While effective, daily injections are burdensome and can compromise adherence. In recent years, novel injection treatments requiring less frequent administration for growth hormone deficiency (GHD) have been developed. A targeted, pragmatic literature review was conducted to summarize and document the patient experience of moving from daily to less frequent injections, with a specific focus on changing from daily to weekly injection treatments in pediatric GHD (pGHD).

OBJECTIVE

Explore and describe the patient experience when switching from a daily to a less frequent injection schedule for GHD.

METHODS

Targeted literature searches were conducted to identify literature describing the patient experience of moving from a daily to weekly injection in GHD. Supplementary searches were conducted to identify literature describing the patient experience of moving from daily to less frequent injection regimens in other medical conditions.

RESULTS

Across searches, 1,691 abstracts were reviewed and 13 articles were included in the final analysis. These publications reported that patients moving to less frequent injections across a variety of conditions, including GHD, experienced increased convenience and satisfaction, higher adherence rates, fewer adverse events, and improved quality of life. Less frequent injections were also reported to be at least as efficacious as daily treatments.

CONCLUSIONS

Less frequent injections in GHD and as other conditions are less burdensome, positively benefit patients, and result in improved adherence that may lead to improved clinical outcomes. Clinicians may consider weekly regimens as an effective alternative for patients, in particular in pGHD, especially when missed injections can negatively impact treatment outcomes. More research is needed to better understand the real-world benefits of injectable therapies that require less frequent administration (e.g., weekly versus daily).

Growth hormone concentration and risk of all-cause and cardiovascular mortality: The REasons for Geographic And Racial Disparities in Stroke (REGARDS) study

BACKGROUND AND AIMS

Identifying individuals at elevated risk for mortality, especially from cardiovascular disease, may help guide testing and treatment. Risk factors for mortality differ by sex and race. We investigated the association of growth hormone (GH) with all-cause and cardiovascular mortality in a racially diverse cohort in the United States.

METHODS

Among an age, sex and race stratified subgroup of 1046 Black and White participants from the REasons for Geographic And Racial Disparities in Stroke (REGARDS) study, 881 had GH available; values were log₂ transformed. Associations with all-cause and cardiovascular mortality were assessed in the whole subgroup, and by sex and race, using multivariable Cox-proportional hazard models and C-index.

RESULTS

The mean age was 67.4 years, 51.1% were women, and 50.2% were Black participants. The median GH was 280 (interquartile range 79-838) ng/L. There were 237 deaths and 74 cardiovascular deaths over a mean of 8.0 years. In multivariable Cox analysis, GH was associated with higher risk of all-cause mortality per doubling (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.09-1.25) and cardiovascular mortality (HR 1.21, 95% CI 1.06-1.37). The association did not differ by sex or race (interaction p > 0.05). The addition of GH to a model of clinical variables significantly improved the C-index compared to clinical model alone for all-cause and cardiovascular death.

CONCLUSIONS

Higher fasting GH was associated with higher risk of all-cause and cardiovascular mortality and improved risk prediction, regardless of sex or race.

The association between idiopathic scoliosis and growth hormone treatment in short children

PURPOSE

Idiopathic scoliosis is the most common form of scoliosis, and the risk of onset and progression has been found to correlate with growth spurts. Therefore, treatment with recombinant human growth hormone (GH) treatment in short children may initiate and/or aggravate scoliosis. The aim of this study was to investigate the relationship between idiopathic scoliosis and GH treatment in short children.

METHODS

The medical records of 113 subjects seen at the participating institution between January 2010 and December 2020 and who were diagnosed with GH deficiency and small for gestational age, had idiopathic short stature, and were treated with GH for at least one year were reviewed. Scoliosis was defined as a Cobb angle greater than 10 degrees as assessed using a spine x-ray. Clinical data and laboratory findings before and 12 months after GH treatment were compared.

RESULTS

There was significant increase in height, height-standard deviation score, insulin-like growth factor 1, and insulin-like growth factor binding protein 3 (p<0.001) with GH treatment. However, there were no significant differences in the average Cobb angle (6.2°±3.3° vs. 6.1°±3.5°, p=0.842) and the prevalence of scoliosis (9.7% vs. 13.3%, p=0.481) before and after one year of GH treatment. A comparative analysis of both initial Cobb angle and change in Cobb angle during GH treatment showed no relationship with other factors.

CONCLUSION

Although GH treatment in short children increased height and growth velocity, it was not associated with development or aggravation of idiopathic scoliosis.

Facile expression and purification of active human growth hormone in E. coli by a cleavable self-aggregating tag scheme

Human growth hormone (hGH) plays an important role in growth control, growth promotion, cell development, and regulation of numerous metabolic pathways in the human body and has been approved by the U.S. FDA for the treatment of several human dysfunctions. Over-expression of recombinant hGH (rhGH) affords a misfolded form in cytoplasm of Escherichia coli, and the refolding step required to obtain active rhGH greatly affects its production costs. Herein, the cleavable self-aggregating tag (cSAT) scheme was used for the expression and purification of rhGH in E. coli. Four aggregating tags (L₆KD/α3-peptide/EFK8/ELK16) successfully drove rhGH into active protein aggregates. After the Mxe GyrA intein-mediated cleavage, 2.8-21.4 μg rhGH/mg wet cell weight was obtained at laboratory scale, of which the L₆KD fusion achieved the highest rhGH yield. The further refined rhGH maintained 92% of the bioactivity compared to commercial rhGH. The self-assembling of the aggregating tag might physically separate the hGH polypeptide chains, which in turn was beneficial to its folding into the active form. This study provided a simple and cost-effective approach for active rhGH production, and suggested an opportunity for improve folding of recombinant proteins in E. coli.

Femoral neck-shaft angle and bone age in 4- to 24-year-olds based on 1005 EOS three-dimensional reconstructions

The aim of the study was to assess the correlation between femoral neck-shaft angles (NSAs) and skeletal maturity in EOS reconstructions from a large population of children. Full-body three-dimensional (3D) reconstructions were generated from 1005 children and young adults (4-24 years old; 449 male, 556 female) using the EOS three-dimensional/3D scanner, with images taken during routine clinical practice. The true NSAs were measured and assessed for correlation with individuals' chronological age and bone age, based on cervical vertebral morphology. Statistical analysis was performed using Spearman correlation, independent t-test and multiple linear regression. NSAs of older and younger individuals within each bone age group and chronological age were further assessed by t-test. NSA values fell from mean 131.89° ± 6.07° at 4 years old to 128.85° ± 4.46° at the age of 16, with only minor decreases thereafter. Significantly higher NSAs (3.16° and 4.45°, respectively) were found in those with a bone age advanced or delayed by more two or more stages compared to their peers of the same chronological age (P < 0.001; P < 0.001). Similarly, within most bone age stages, individuals of advanced or delayed chronological age exhibited elevated values (mean difference ranged from 2.9° to 8.9°, P < 0.05). Incorporation of bone age assessment into proximal femoral evaluation allowed identification of 'fast maturing' and 'slow maturing' sub-categories in developing children, with different expected NSAs. The earlier ossification seen in faster-maturing individuals may lead to the NSA becoming fixed in a more immature valgus conformation.

Development and Psychometric Evaluation of the Life Interference Questionnaire for Growth Hormone Deficiency (LIQ-GHD) to Assess Growth Hormone Injection Burden in Children and Adults

Background

Current recombinant human growth hormone (r-hGH) replacement therapy involves long-term daily subcutaneous injections to treat growth hormone deficiency (GHD) in children and adults. Daily r-hGH injections can be burdensome, often resulting in poor treatment compliance. Clinical outcome assessments (COAs) can capture the burden of these injections from the patient (and caregiver) perspective and may demonstrate the benefit of a less-frequent r-hGH injection regimen, which may ultimately improve treatment compliance and long-term outcomes.

Objective

To address this knowledge gap, qualitative research was conducted to inform the development of a new Life Interference Questionnaire for Growth Hormone Deficiency (LIQ-GHD), designed to measure the experiences of patients taking r-hGH GHD injections. A second objective was to evaluate the hypothesized factor structure and preliminary performance of the LIQ-GHD in a cross-sectional observational study.

Methods

An empirical literature review and expert advice meetings were conducted to inform development of the draft LIQ-GHD (pediatric and adult versions). In-person concept elicitation and cognitive debriefing interviews were conducted with GHD patients (and patient dyads including caregivers) to explore and confirm concept coverage and evaluate respondents’ ability to understand the questionnaire. The draft LIQ-GHD was then tested in a cross-sectional field study involving pediatric and adult patients receiving daily r-hGH injections for GHD. The factor structure, reliability, and validity were analyzed for the overall sample and for pediatric, adolescent, and adult subgroups.

Results

Results from the literature review and input from six experts were used to develop and refine the LIQ-GHD, with content covering pen ease of use; regimen convenience; life interference due to regimen; benefit/satisfaction/willingness to continue treatment; regimen choice/preference; intent to comply with regimen; injection-related signs/symptoms; and reasons for missed injections. Twenty-one patient interviews confirmed comprehensive concept coverage and patient/caregiver comprehension of the LIQ-GHD. A total of 224 patients (n = 70 children/caregiver dyads, n = 79 adolescents/caregiver dyads, n = 75 adults) participated in the field study. While most items showed floor effects, confirmatory factor analysis fit statistics were good for the overall sample (root mean square error of approximation = 0.07, comparative fit index = 0.98) and for the full pediatric sample after dropping co-dependent questions from the model. Cronbach’s alpha (α) ranged from 0.746 to 0.905 and intra-class correlation coefficients ranged from 0.761 to 0.918 for the overall sample on LIQ-GHD domains. Scores correlated as predicted with an existing criterion measure in the overall sample and LIQ-GHD domain scores distinguished known groups as expected.

Conclusions

The LIQ-GHD is a new COA for the measurement of r-hGH injection treatment burden. This research provides evidence supporting its content validity, hypothesized factor structure, score reliability, and construct validity in pediatric and adult populations.

Effectiveness and Overall Safety of NutropinAq® for Growth Hormone Deficiency and Other Paediatric Growth Hormone Disorders: Completion of the International Cooperative Growth Study, NutropinAq® European Registry (iNCGS)

Objective

The International Cooperative Growth Study, NutropinAq® European Registry (iNCGS) (NCT00455728) monitored long-term safety and effectiveness of recombinant human growth hormone (rhGH; NutropinAq® [somatropin]) in paediatric growth disorders.

Methods

Open-label, non-interventional, post-marketing surveillance study recruiting children with growth disorders. Endpoints included gain in height standard deviation score (SDS), adult height, and occurrence of adverse events (AEs).

Results

2792 patients were enrolled. 2082 patients (74.6%) had growth hormone deficiency (GHD), which was isolated idiopathic in 1825 patients (87.7%). Non-GHD diagnoses included Turner syndrome (TS) (n=199), chronic renal insufficiency (CRI) (n=10), other non-GHD (n=498), and missing data for three participants. Improvements from baseline height SDS occurred at all time points to Month 132, and in all subgroups by disease aetiology. At Month 12, mean (95% CI) change in height SDS by aetiology was: idiopathic GHD 0.63 (0.61;0.66), organic GHD 0.71 (0.62;0.80), TS 0.59 (0.53; 0.65), CRI 0.54 (-0.49;1.56), and other non-GHD 0.64 (0.59;0.69). Mean height ( ± SD) at the last visit among the 235 patients with adult or near-adult height recorded was 154.0 cm ( ± 8.0) for girls and 166.7 cm ( ± 8.0) for boys. The most frequent biological and clinical non-serious drug-related AEs were increased insulin-like growth factor concentrations (314 events) and injection site haematoma (99 events). Serious AEs related to rhGH according to investigators were reported (n=30); the most frequent were scoliosis (4 events), epiphysiolysis (3 events), and strabismus (2 events).

Conclusions

There was an improvement in mean height SDS in all aetiology subgroups after rhGH treatment. No new safety concerns were identified.

Association of thyroid autoimmunity and the response to recombinant human growth hormone in Turner syndrome

OBJECTIVES

Short stature and thyroid autoimmunity are common comorbidities in Turner syndrome (TS). Recombinant human growth hormone (rhGH) significantly improves height growth in TS individuals. This study aims to investigate the association of thyroid autoimmunity and the response to rhGH treatment in TS patients.

METHODS

Medical records of 494 patients with TS were reviewed. Among 126 patients who regularly tested for thyroid autoantibodies, 108 patients had received rhGH treatment. Clinical characteristics, including karyotype and the presence of autoimmune thyroid diseases, as well as rhGH treatment records were analyzed. Height velocity (HV) of patients with or without thyroid autoimmunity was compared to assess the response to rhGH treatment. For patients who developed thyroid autoantibodies during rhGH treatment, HV before and after antibody presence were compared.

RESULTS

45XO monosomy presented in 36% (176/496) of patients. 42.1% of patients (53/126) had elevated circulating anti-thyroid peroxidase antibody and anti-thyroglobulin antibody. In 108 patients who received rhGH treatment, HVs were significantly correlated to age, height, weight and BMI at the initiation of treatment. For patients who developed thyroid autoantibodies during rhGH treatment, HVs after thyroid autoantibody presence significantly decreased compared with HVs before thyroid autoantibody detection (n=44, p=0.0017).

CONCLUSIONS

Our data suggested that in TS patients who developed thyroid autoantibodies during rhGH treatment, the response to rhGH is negatively associated with the development of thyroid autoimmunity.

Early overnutrition sensitizes the growth hormone axis to the impact of diet-induced obesity via sex-divergent mechanisms

In addition to its essential role in the physiological control of longitudinal growth, growth-hormone (GH) is endowed with relevant metabolic functions, including anabolic actions in muscle, lipolysis in adipose-tissue and glycemic modulation. Adult obesity is known to negatively impact GH-axis, thereby promoting a vicious circle that may contribute to the exacerbation of the metabolic complications of overweight. Yet, to what extent early-overnutrition sensitizes the somatotropic-axis to the deleterious effects of obesity remains largely unexplored. Using a rat-model of sequential exposure to obesogenic insults, namely postnatal-overfeeding during lactation and high-fat diet (HFD) after weaning, we evaluated in both sexes the individual and combined impact of these nutritional challenges upon key elements of the somatotropic-axis. While feeding HFD per se had a modest impact on the adult GH-axis, early overnutrition had durable effects on key elements of the somatotropic-system, which were sexually different, with a significant inhibition of pituitary gene expression of GH-releasing hormone-receptor (GHRH-R) and somatostatin receptor-5 (SST5) in males, but an increase in pituitary GHRH-R, SST2, SST5, GH secretagogue-receptor (GHS-R) and ghrelin expression in females. Notably, early-overnutrition sensitized the GH-axis to the deleterious impact of HFD, with a significant suppression of pituitary GH expression in both sexes and lowering of circulating GH levels in females. Yet, despite their similar metabolic perturbations, males and females displayed rather distinct alterations of key somatotropic-regulators/ mediators. Our data document a synergistic effect of postnatal-overnutrition on the detrimental impact of HFD-induced obesity on key elements of the adult GH-axis, which is conducted via mechanisms that are sexually-divergent.

Growth hormone therapy for people with thalassaemia

BACKGROUND

Thalassaemia is a recessively-inherited blood disorder that leads to anaemia of varying severity. In those affected by the more severe forms, regular blood transfusions are required which may lead to iron overload. Accumulated iron from blood transfusions may be deposited in vital organs including the heart, liver and endocrine organs such as the pituitary glands which can affect growth hormone production. Growth hormone deficiency is one of the factors that can lead to short stature, a common complication in people with thalassaemia. Growth hormone replacement therapy has been used in children with thalassaemia who have short stature and growth hormone deficiency. This review on the role of growth hormone was originally published in September 2017 and updated in April 2020.

OBJECTIVES

To assess the benefits and safety of growth hormone therapy in people with thalassaemia.

SEARCH METHODS

We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of latest search: 14 November 2019. We also searched the reference lists of relevant articles, reviews and clinical trial registries. Date of latest search: 06 January 2020.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing the use of growth hormone therapy to placebo or standard care in people with thalassaemia of any type or severity.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion. Data extraction and assessment of risk of bias were also conducted independently by two authors. The certainty of the evidence was assessed using GRADE criteria.

MAIN RESULTS

We included one parallel trial conducted in Turkey. The trial recruited 20 children with homozygous beta thalassaemia who had short stature; 10 children received growth hormone therapy administered subcutaneously on a daily basis at a dose of 0.7 IU/kg per week and 10 children received standard care. The overall risk of bias in this trial was low except for the selection criteria and attrition bias which were unclear. The certainty of the evidence for all major outcomes was moderate, the main concern was imprecision of the estimates due to the small sample size leading to wide confidence intervals. Final height (cm) (the review's pre-specified primary outcome) and change in height were not assessed in the included trial. The trial reported no clear difference between groups in height standard deviation (SD) score after one year, mean difference (MD) -0.09 (95% confidence interval (CI) -0.33 to 0.15 (moderate-certainty evidence). However, modest improvements appeared to be observed in the following key outcomes in children receiving growth hormone therapy compared to control (moderate-certainty evidence): change between baseline and final visit in height SD score, MD 0.26 (95% CI 0.13 to 0.39); height velocity, MD 2.28 cm/year (95% CI 1.76 to 2.80); height velocity SD score, MD 3.31 (95% CI 2.43 to 4.19); and change in height velocity SD score between baseline and final visit, MD 3.41 (95% CI 2.45 to 4.37). No adverse effects of treatment were reported in either group; however, while there was no clear difference between groups in the oral glucose tolerance test at one year, fasting blood glucose was significantly higher in the growth hormone therapy group compared to control, although both results were still within the normal range, MD 6.67 mg/dL (95% CI 2.66 to 10.68). There were no data beyond the one-year trial period.

AUTHORS' CONCLUSIONS

A small single trial contributed evidence of moderate certainty that the use of growth hormone for a year may improve height velocity of children with thalassaemia although height SD score in the treatment group was similar to the control group. There are no randomised controlled trials in adults or trials that address the use of growth hormone therapy over a longer period and assess its effect on final height and quality of life. The optimal dosage of growth hormone and the ideal time to start this therapy remain uncertain. Large well-designed randomised controlled trials over a longer period with sufficient duration of follow up are needed.

The heart in growth hormone (GH) deficiency and the cardiovascular effects of GH

Besides its effects on longitudinal growth in childhood and its metabolic effects with consequences on body composition and lipid levels, growth hormone (GH) has important roles on maintaining the structure and function of the normal adult heart. GH/insulin like growth factor-I (IGF-I) also interacts with the vascular system and plays a role in the regulation of vascular tone. GH deficiency (GHD) in adulthood is associated with increased fat mass (particularly visceral) and abnormal lipid profile, which may contribute to the excess cardiovascular mortality observed in patients with panhypopituitarism. Treatment with GH improved body composition (by increasing lean mass and decreasing fat mass) and improved lipid profile. It also has beneficial effects on vascular walls. The improvement in cardiovascular morbidity and mortality induced by GH is less clear as data are scarce and obtained on small populations. The importance of alteration in cardiac morphology and function observed in GHD is debated, particularly when cardiac magnetic resonance is used rather than echocardiography. The effects of treatment with GH on heart function and morphology are modest when studied by echocardiography.

Quantification of osteoblastic activity in epiphyseal growth plates by quantitative bone SPECT/CT

OBJECTIVE

Quantifying the function of the epiphyseal plate is worthwhile for the management of children with growth disorders. The aim of this retrospective study was to quantify the osteoblastic activity at the epiphyseal plate using the quantitative bone SPECT/CT.

MATERIALS AND METHODS

We enrolled patients under the age of 20 years who received Tc-99m hydroxymethylene diphosphonate bone scintigraphy acquired by a quantitative SPECT/CT scanner. The images were reconstructed by ordered subset conjugate-gradient minimizer, and the uptake on the distal margin of the femur was quantified by peak standardized uptake value (SUVpeak). A public database of standard body height was used to calculate growth velocities (cm/year).

RESULTS

Fifteen patients (6.9-19.7 years, 9 female, 6 male) were enrolled and a total of 25 legs were analyzed. SUVpeak in the epiphyseal plate was 18.9 ± 2.4 (average ± standard deviation) in the subjects under 15 years and decreased gradually by aging. The SUVpeak correlated significantly with the age- and sex-matched growth velocity obtained from the database (R² = 0.83, p < 0.0001).

CONCLUSION

The SUV measured by quantitative bone SPECT/CT was increased at the epiphyseal plates of children under the age of 15 years in comparison with the older group, corresponding to higher osteoblastic activity. Moreover, this study suggested a correlation between growth velocity and the SUV. Although this is a small retrospective pilot study, the objective and quantitative values measured by the quantitative bone SPECT/CT has the potential to improve the management of children with growth disorder.

Molecular therapeutic strategies for FGFR3 gene-related skeletal dysplasia

The FGFR3 gene encodes fibroblast growth factor receptor 3 protein, a negative regulator of chondrogenesis. Gain-of-function mutations result in constitutively activated FGFR3, leading to aberrant signal transduction, and accounting for inhibition of chondrocyte proliferation and differentiation. Generally, these pathogenic mutations maintain FGFR3 in an active state and cause diverse phenotypes in patients with skeletal dysplasia. For decades, studies have revealed the molecular mechanisms of constitutively activated FGFR3 and relevant therapeutic strategies. By modulating the FGFR3-induced signalling pathway with methods such as blocking binding between ligands and receptors, blocking tyrosine kinase activities, or antagonising the FGFR3 downstream signalling pathway, these strategies offer the possibility to ameliorate FGFR3 gene-related skeletal dysplasia phenotypes. In this review, we describe the mechanisms of potential therapeutic targets and underlying regulators and then systematically review molecular therapeutic strategies for FGFR3 gene-related skeletal dysplasia based on current knowledge.

Effects of exogenous growth hormone administration on dexamethasone-induced growth impairment in adolescent male rats

Growth impairment (GI) is one of the adverse effects of dexamethasone (DXM), and growth hormone (GH) has been used clinically to improve GI. The present study aimed to evaluate the manner in which DXM disturbs the growth rate of longitudinal bones, and the recovery effects of GH on DXM-induced GI in the longitudinal bones of adolescent male rats. In the first experiment, DXM (0, 0.5, 1, 2 and 5 mg/kg) was administered subcutaneously to identify a potential dose-dependent activity and calculate the median effective dose (ED50) of DXM-induced GI. The ED50 was identified to be 1.15 mg/kg. In the second experiment, GH (0, 2.5, 5 and 10 mg/kg) with 1.15 mg/kg DXM was injected subcutaneously to assess the recovery effects of GH on DXM-induced GI. The growth rates of the longitudinal bones, total height of the growth plate, local mRNA expressions of insulin-like growth factor 1 (IGF-1), GH receptor (GHR) and IGF-1 receptor (IGF-1R), and local protein expression of IGF-1 were measured to evaluate the recovery effects of GH on DXM-induced GI. The local expressions of IGF-1, GHR and IGF-1R mRNA, and IGF-1 protein were measured using quantitative polymerase chain reaction following laser microdissection and antigen-specific immunohistochemistry, respectively. GH administration partially recovered DXM-induced GI in the longitudinal bones and growth plate. GH significantly increased the levels of IGF-1, GHR and IGF-1R mRNA in the proliferative zone of the control group (P<0.05), whereas it failed to increase them in the proliferative zone of the DXM-treated group. Furthermore, GH increased the levels of IGF-1, GHR and IGF-1R mRNA in the hypertrophic zone of both the vehicle and DXM-treated groups (P<0.05). Immunohistochemical analysis of IGF-1 protein expression revealed a similar pattern to that of IGF-1 mRNA. These results suggest that increased GH insensitivity in the proliferative zone of the growth plate, induced by DXM, leads to GI in longitudinal bones. Thus, combined administration of GH with GH insensitivity-alleviating medications may be more effective in the treatment of DXM-induced GI.

Physiologic Growth Hormone-Replacement Therapy and Craniopharyngioma Recurrence in Pediatric Patients: A Meta-Analysis

OBJECTIVE

A systematic review and meta-analysis were conducted to examine the effect of growth hormone-replacement therapy (GHRT) on the recurrence of craniopharyngioma in children.

METHODS

PubMed, Embase, and Cochrane databases were searched through April 2017 for studies that evaluated the effect of GHRT on the recurrence of pediatric craniopharyngioma. Pooled effect estimates were calculated with fixed- and random-effects models.

RESULTS

Ten studies (n = 3487 patients) met all inclusion criteria, including 2 retrospective cohorts and 8 case series. Overall, 3436 pediatric patients were treated with GHRT after surgery and 51 were not. Using the fixed effect model, we found that the overall craniopharyngioma recurrence rate was lower among children who were treated by GHRT (10.9%; 95% confidence interval 9.80%-12.1%; I² = 89.1%; P for heterogeneity <0.01; n = 10 groups) compared with those who were not (35.2%; 95% confidence interval 23.1%-49.6%; I² = 61.7%; P for heterogeneity = 0.11; n = 3); the P value comparing the 2 groups was <0.01. Among patients who were treated with GHRT, subgroup analysis revealed that there was a greater prevalence of craniopharyngioma recurrence among studies conducted outside the United States (P < 0.01), single-center studies (P < 0.01), lower impact factor studies (P = 0.03), or studies with a lower quality rating (P = 0.01). Using the random-effects model, we found that the results were not materially different except for when stratifying by GHRT, impact factor, or study quality; this led to nonsignificant differences. Both Begg's rank correlation test (P = 0.7) and Egger's linear regression test (P = 0.06) indicated no publication bias.

CONCLUSIONS

This meta-analysis demonstrated a lower recurrence rate of craniopharyngioma among children treated with GHRT than those who were not.

Growth hormone therapy for people with thalassaemia

BACKGROUND

Thalassaemia is a recessively-inherited blood disorder that leads to anaemia of varying severity. In those affected by the more severe forms, regular blood transfusions are required which may lead to iron overload. Accumulated iron from blood transfusions may be deposited in vital organs including the heart, liver and endocrine organs such as the pituitary glands which can affect growth hormone production. Growth hormone deficiency is one of the factors that can lead to short stature, a common complication in people with thalassaemia. Growth hormone replacement therapy has been used in children with thalassaemia who have short stature and growth hormone deficiency.

OBJECTIVES

To assess the benefits and safety of growth hormone therapy in people with thalassaemia.

SEARCH METHODS

We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles, reviews and clinical trial registries. Our database and trial registry searches are current to 10 August 2017 and 08 August 2017, respectively.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing the use of growth hormone therapy to placebo or standard care in people with thalassaemia of any type or severity.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion. Data extraction and assessment of risk of bias were also conducted independently by two authors. The quality of the evidence was assessed using GRADE criteria.

MAIN RESULTS

One parallel trial conducted in Turkey was included. The trial recruited 20 children with homozygous beta thalassaemia who had short stature; 10 children received growth hormone therapy administered subcutaneously on a daily basis at a dose of 0.7 IU/kg per week and 10 children received standard care. The overall risk of bias in this trial was low except for the selection criteria and attrition bias which were unclear. The quality of the evidence for all major outcomes was moderate, the main concern was imprecision of the estimates due to the small sample size leading to wide confidence intervals. Final height (cm) (the review's pre-specified primary outcome) and change in height were not assessed in the included trial. The trial reported no clear difference between groups in height standard deviation (SD) score after one year, mean difference (MD) -0.09 (95% confidence interval (CI) -0.33 to 0.15 (moderate quality evidence). However, modest improvements appeared to be observed in the following key outcomes in children receiving growth hormone therapy compared to control (moderate quality evidence): change between baseline and final visit in height SD score, MD 0.26 (95% CI 0.13 to 0.39); height velocity, MD 2.28 cm/year (95% CI 1.76 to 2.80); height velocity SD score, MD 3.31 (95% CI 2.43 to 4.19); and change in height velocity SD score between baseline and final visit, MD 3.41 (95% CI 2.45 to 4.37). No adverse effects of treatment were reported in either group; however, while there was no clear difference between groups in the oral glucose tolerance test at one year, fasting blood glucose was significantly higher in the growth hormone therapy group compared to control, although both results were still within the normal range, MD 6.67 mg/dL (95% CI 2.66 to 10.68). There were no data beyond the one-year trial period.

AUTHORS' CONCLUSIONS

A small single trial contributed evidence of moderate quality that the use of growth hormone for a year may improve height velocity of children with thalassaemia although height SD score in the treatment group was similar to the control group. There are no randomised controlled trials in adults or trials that address the use of growth hormone therapy over a longer period and assess its effect on final height and quality of life. The optimal dosage of growth hormone and the ideal time to start this therapy remain uncertain. Large well-designed randomised controlled trials over a longer period with sufficient duration of follow up are needed.

One-year GH replacement therapy reduces early cardiac target organ damage (TOD) in adult GHD patients

Hypopituitarism reduces life expectancy and increases the risk of cardiovascular and cerebrovascular diseases, as well as death. Abnormalities in the cardiovascular system may be independently related to GH deficiency (GHD). The aim of this study was to prospectively investigate coronary flow reserve and diastolic function in GHD adult patients at diagnosis and after 1 year of GH replacement therapy. As control group, an age- and sex-matched population was chosen. All patients and controls were non-smokers, non-diabetic, and normotensive, with no history of vascular disease. 14 patients with adult-onset GHD and 17 controls represent the two study groups. Anthropometric data, blood pressure, lipid profile, glycosylated hemoglobin (HbA1c) and IGF-I plasma levels, coronary flow reserve (CFR), and LV diastolic function (evaluated by E/A) were collected in all subjects before and after 12 months of GH replacement therapy. Compared with controls, systolic and diastolic blood pressure and LDL cholesterol levels were significantly higher at baseline and return, comparable to controls after 1 year of GH replacement (GHRT). GHD patients showed a blunted CFR at baseline (P < 0.001) and a significant improvement after GHRT, returning to values comparable with those recorded in the control group. In addition, after therapy a significant (P < 0.001) improvement in E/A was recorded. One year of GH therapy improves CFR and E/A in the patient population analyzed, thereby encouraging the early start of GHRT.

Exploiting Nanobodies in the Detection and Quantification of Human Growth Hormone via Phage-Sandwich Enzyme-Linked Immunosorbent Assay

BACKGROUND

Monitoring blood levels of human growth hormone (hGH) in most children with short stature deficiencies is crucial for taking a decision of treatment with extended course of daily and expensive doses of recombinant hGH (rhGH or Somatropin^®). Besides, misusing of rhGH by sportsmen is banned by the World Anti-Doping Agency and thus sensitive GH-detecting methods are highly welcome in this field. Nanobodies are the tiniest antigen-binding entity derived from camel heavy chain antibodies. They were successfully generated against numerous antigens including hormones.

METHODS

A fully nanobody-based sandwich ELISA method was developed in this work for direct measurement of GH in biological samples.

RESULTS

Two major characteristics of nanobody were exploited for this goal: the robust and stable structure of the nanobody (NbGH04) used to capture hGH from tested samples, and the great ability of tailoring, enabling the display of the anti-GH detector nanobody (NbGH07) on the tip of M13-phage. Such huge, stable, and easy-to-prepare phage-Nb was used in ELISA to provide an amplified signal. Previously, NbGH04 was retrieved on immobilized hGH by phage display from a wide "immune" cDNA library prepared from a hGH-immunized camel. Here, and in order to assure epitope heterogeneity, NbGH07 was isolated from the same library using NbGH04-captured hGH as bait. Interaction of both nanobodies with hGH was characterized and compared with different anti-GH nanobodies and antibodies. The sensitivity (~0.5 ng/ml) and stability of the nanobody-base sandwich ELISA were assessed using rhGH before testing in the quantification of hGH in blood sera and cell culture supernatants.

CONCLUSION

In regard to all advantages of nanobodies; stability, solubility, production affordability in Escherichia coli, and gene tailoring, nanobody-based phage sandwich ELISA developed here would provide a valuable method for hGH detection and quantification.

High level expression of recombinant human growth hormone in Escherichia coli: crucial role of translation initiation region

For high-throughput production of recombinant protein in Escherichia coli (E. coli), besides important parameters such as efficient vector with strong promoter and compatible host, other important issues including codon usage, rare codons, and GC content specially at N-terminal region should be considered. In the current study, the effect of decreasing the percentage of GC nucleotides and optimizing codon usage at N-terminal region of human growth hormone (hGH) cDNA on the level of its expression in E. coli were investigated. Mutation in cDNA of hGH was performed through site-directed mutagenesis using PCR. Then, the mutant genes were amplified and cloned into the expression vector, pET-28a. The new constructs were transformed into the BL21(DE3) strain of E. coli and chemically induced for hGH expression. At the final stage, expressed proteins were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), scanning gel densitometry, and western blot. SDS-PAGE scanning gel densitometry assay and western blot analysis revealed higher expression level of hGH by using the two new expressions constructs (mutant genes vectors with decreasing GC content and optimized-codon usage at N-terminal of cDNA) in comparison with wild gene expression vector. Obtained results demonstrated that decreasing the GC nucleotide content and optimization of codon usage at N-terminal of the hGH cDNA could significantly enhance the expression of the target protein in E. coli. Our results highlight the important role of both 5´ region of the heterologous genes in terms of codon usage and also GC content on non-host protein expression in E. coli.

Growth and growth hormone: An overview

Growth is a good indicator of a child's health. Growth disturbances, including short stature or growth failure, could be indications of illnesses such as chronic disease, nutritional deficits, celiac disease or hormonal abnormalities. Therefore, a careful assessment of the various requirements for normal growth needs to be done by history, physical examination, and screening laboratory tests. More details will be reviewed about the GH-IGF axis, its abnormalities with special emphasis on GH deficiency, its diagnosis and treatment. GH treatment indications in the US will be reviewed and a few only will be highlighted. They will include GH deficiency, as well as the treatment of children born SGA, including the results of a US study using FDA approved dose of 0.48mg/kg/week. GH deficiency in adults will also be briefly reviewed. Treatment of patients with SHOX deficiency will also be discussed. Possible side effects of GH treatment and the importance of monitoring safety will be highlighted.

A Randomized Safety and Efficacy Study of Somavaratan (VRS-317), a Long-Acting rhGH, in Pediatric Growth Hormone Deficiency

CONTEXT

Somavaratan (VRS-317) is a long-acting form of recombinant human GH under development for children and adults with GH deficiency (GHD).

OBJECTIVES

To determine the optimal somavaratan dose regimen to normalize IGF-1 in pediatric GHD and to evaluate safety and efficacy of somavaratan over 6 months.

DESIGN

Open-label, multicenter, single ascending dose study followed by 6-month randomized comparison of 3 dosing regimens.

SETTING

Twenty-five United States pediatric endocrinology centers.

PATIENTS

Naive-to-treatment, prepubertal children with GHD (n = 68).

INTERVENTION(S)

Patients received single sc doses of somavaratan (0.8, 1.2, 1.8, 2.7, 4.0, or 6.0 mg/kg) during the 30-day dose-finding phase, then were randomized to somavaratan 1.15 mg/kg weekly, 2.5 mg/kg twice monthly, or 5.0 mg/kg monthly for 6 months.

MAIN OUTCOME MEASURES

Safety, pharmacokinetics, pharmacodynamics, 6-month height velocity (HV).

RESULTS

Somavaratan pharmacokinetics was linearly proportional to dose; dose-dependent increases in the magnitude and duration of IGF-1 responses enabled weekly, twice-monthly or monthly dosing. A single dose of somavaratan sustained IGF-1 responses for up to 1 month. No somavaratan or IGF-1 accumulation occurred with repeat dosing. Mean annualized HVs for somavaratan administered monthly, twice monthly, or weekly (7.86 ± 2.5, 8.61 ± 2.7, and 7.58 ± 2.5 cm/y, respectively) were similar between groups. Adverse events were mostly mild and transient.

CONCLUSIONS

Somavaratan demonstrated clinically meaningful improvements in HV and IGF-1 in prepubertal children with GHD, with no significant differences between monthly, twice-monthly, or weekly dosing.

A dosimetric comparison of proton and intensity modulated radiation therapy in pediatric rhabdomyosarcoma patients enrolled on a prospective phase II proton study

BACKGROUND

Pediatric rhabdomyosarcoma (RMS) is highly curable, however, cure may come with significant radiation related toxicity in developing tissues. Proton therapy (PT) can spare excess dose to normal structures, potentially reducing the incidence of adverse effects.

METHODS

Between 2005 and 2012, 54 patients were enrolled on a prospective multi-institutional phase II trial using PT in pediatric RMS. As part of the protocol, intensity modulated radiation therapy (IMRT) plans were generated for comparison with clinical PT plans.

RESULTS

Target coverage was comparable between PT and IMRT plans with a mean CTV V95 of 100% for both modalities (p=0.82). However, mean integral dose was 1.8 times higher for IMRT (range 1.0-4.9). By site, mean integral dose for IMRT was 1.8 times higher for H&N (p<0.01) and GU (p=0.02), 2.0 times higher for trunk/extremity (p<0.01), and 3.5 times higher for orbit (p<0.01) compared to PT. Significant sparing was seen with PT in 26 of 30 critical structures assessed for orbital, head and neck, pelvic, and trunk/extremity patients.

CONCLUSIONS

Proton radiation lowers integral dose and improves normal tissue sparing when compared to IMRT for pediatric RMS. Correlation with clinical outcomes is necessary once mature long-term toxicity data are available.

Switching to Omnitrope(®) from Other Recombinant Human Growth Hormone Therapies: A Retrospective Study in an Integrated Healthcare System

INTRODUCTION

This study was conducted using an integrated retrospective database to evaluate the effectiveness of Omnitrope(®) (Sandoz) on children with growth hormone deficiency (GHD), idiopathic short stature (ISS), and Turner Syndrome (TS) who switched from a non-Omnitrope recombinant human growth hormone (rhGH) preparation during routine clinical care.

METHODS

This was a retrospective study which identified patients with GHD, ISS, and TS during the study time period of January 1, 2006 and July 31, 2011. Patients were included if they switched to Omnitrope from another non-Omnitrope rhGH therapy during the study time period, were <18 years of age at time of switch, and on a prior rhGH therapy for at least 15 months pre-switch and on Omnitrope for 15 months post-switch. Auxological parameters (height, height standard deviation score [HSDS], height velocity [HV], and height velocity standard deviation score [HVSDS]) were evaluated during post-switch.

RESULTS

One hundred and three patients were identified: GHD (n = 57), ISS (n = 26), and TS (n = 20). There was continuous growth in height for all 103 patients with an average rate of 6.52 cm over the 15-month post-switch period. Patients with GHD grew an average rate of 6.30 cm, patients with ISS grew an average rate of 6.58 cm, and patients with TS grew an average rate of 6.52 cm over the 15-month post-switch period. The average rate of HSDS was increased by 0.04 for all patients. The HV and HVSDS demonstrated the expected decline with advancing age and prolonged duration of treatment.

CONCLUSIONS

The growth trajectories of rhGH-treated patients were not negatively impacted by switching to Omnitrope and growth rates remained as expected prior to the switch.

Generation and characterization of nanobodies against rhGH expressed as sfGFP fusion protein

Growth hormone (GH) deficiencies are diagnosed in most children with short stature and treated with a long course of administrating expensive and daily doses of recombinant human GH (rhGH or Somatropin®). This work describes for the first time the production of several GH specific nanobodies with great potential in the field of GH production and detection. Nanobodies are the smallest intact antigen binders derived from heavy chain-only antibodies (HCAbs) of camelids. They are very stable, highly soluble and are produced as recombinant proteins in Escherichiacoli at an affordable cost for various biotechnological applications. To increase its solubility and immunogenicity, GH was produced as fusion with superfolder green fluorescent protein (sfGFP) and was used in this form to successfully immunize an adult camel. The active involvement of HCAbs in the specific camel immune response encouraged the preparation of large nanobody "immune" library. Phage display biopanning of this library against GH resulted in the isolation of five interesting and different nanobodies, referred to as NbGH01, 02, 03, 04 and 06. All nanobodies were able to recognize GH in its fusion and free formats and the detection sensitivity ranged from 0.5 to 10 ng/ml in sandwich ELISA. Pure rhGH was successfully purified by affinity chromatography, using immobilized NbGH06, from the cleavage reaction of fusion proteins with the tobaccos etch virus (TEV) protease. These specific molecular binders, especially NbGH06, provide valuable tools for rhGH diagnostic as well as for production purposes.

Adult and near-adult height in patients with severe insulin-like growth factor-I deficiency after long-term therapy with recombinant human insulin-like growth factor-I

BACKGROUND

Treatment with recombinant human insulin-like growth factor-I (IGF-I) stimulates linear growth in children with severe IGF-I deficiency (IGFD).

AIMS

To evaluate the efficacy and safety of treatment with IGF-I in patients with severe IGFD treated until adult or near-adult height.

METHODS

Twenty-one children with severe IGFD were treated until adult or near-adult height under a predominantly open-label design. All patients were naive to IGF-I. Recombinant human IGF-I was administered subcutaneously in doses between 60 and 120 µg/kg twice daily. Nine patients received additional therapy with gonadotropin- releasing hormone (GnRH) analog for a mean period of 2.9 ± 1.8 years.

RESULTS

Mean duration of treatment was 10.0 years. Mean height velocity increased from 3.1 cm/year prior to treatment to 7.4 cm/year during the first year of treatment. Height velocities during the subsequent years were lower, but remained above baseline for up to 12 years. Cumulative mean Δ height SD score at (near) adult height was +2. The observed mean gain in height was 13.4 cm more than had been expected without treatment. The adult height achieved by the patients also treated with GnRH analog was not different from those who received IGF-I therapy alone. There were no new safety signals identified in these patients, a subset of those previously reported.

CONCLUSION

Long-term therapy with IGF-I improves adult height of patients with severe IGFD. Most patients did not bring their heights into the normal adult range.

Obesity in the ageing man

As the population is ageing globally, both ageing and obesity are recognized as major public health challenges. The aim of this narrative review is to present and discuss the current evidence on the changes in body composition, energy balance and endocrine environment that occur in the ageing man. Obesity in the ageing man is related to changes in both body weight and composition due to alterations in energy intake and total energy expenditure. In addition, somatopenia (decreased GH secretion), late-onset hypogonadism (LOH), changes in thyroid and adrenal function, as well as changes in appetite-related peptides (leptin, ghrelin) and, most importantly, insulin action are related to obesity, abnormal energy balance, redistribution of the adipose tissue and sarcopenia (decreased muscle mass). A better understanding of the complex relationship of ageing-related endocrine changes and obesity could lead to more effective interventions for elderly men.

The metabolic effects of growth hormone in adipose tissue

There is a general consensus that a reduction in growth hormone (GH) secretion results in obesity. However, the pathophysiologic role of GH in the metabolism of lipids is yet to be fully understood. The major somatic targets of GH are bones and muscles, but GH stimulates lipolysis and seems to regulate lipid deposition in adipose tissue. Patients with isolated GH deficiency (GHD) have enlarged fat depots due to higher fat cell volume, but their fat cell numbers are lower than those of matched controls. The treatment of patients with GH results in a relative loss of body fat and shifts both fat cell number and fat cell volume toward normal, indicating an adipogenic effect of GH. Adults with GHD are characterized by perturbations in body composition, lipid metabolism, cardiovascular risk profile, and bone mineral density. It is well established that GHD is usually accompanied by an increase in fat accumulation; GH replacement in GHD results in the reduction of fat mass, particularly abdominal fat mass. In addition, abdominal obesity results in a secondary reduction in GH secretion that is reversible with weight loss. However, whereas GH replacement in patients with GHD leads to specific depletion of intra-abdominal fat, administering GH to obese individuals does not seem to result in a consistent reduction or redistribution of body fat. Although administering GH to obese non-GHD subjects has only led to equivocal results, more recent studies indicate that GH still remains a plausible metabolic candidate.

Growth hormone and aging

The potential usefulness of growth hormone (GH) as an anti-aging therapy is of considerable current interest. Secretion of GH normally declines during aging and administration of GH can reverse age-related changes in body composition. However, mutant dwarf mice with congenital GH deficiency and GH resistant GH-R-KO mice live much longer than their normal siblings, while a pathological elevation of GH levels reduces life expectancy in both mice and men. We propose that the actions of GH on growth, development, and adult body size may serve as important determinants of aging and life span, while the age-related decline in GH levels contributes to some of the symptoms of aging.

Pharmacology of somatrotropin pegylated by electron-beam synthesis nanotechnology

Pharmacological characteristics of somatotropin pegylated using electron-beam synthesis nanotechnology (PEG-STH) were studied. Oral PEG-STH stimulated the intensity of protein and lipid metabolism and endochondral bone growth without modifying the processes of periosteal and endosteal bone formation. Specific activity of this substance administered orally significantly surpassed that of parenteral non-modified growth hormone.

Growth and growth disorders in children and adolescents

Evaluation of a child's growth is one of the most important aspects of the general pediatric visit. Concerns about abnormal growth are the leading reasons general pediatricians refer patients to a pediatric endocrinologist. There is wide variation in normal growth patterns and an even greater variety of conditions that manifest with growth abnormalities. Here, we review patterns of normal growth in the pediatric and adolescent populations. We then review abnormal patterns of growth that require further evaluation and possible treatment.

Growth hormone secretion after conformal radiation therapy in pediatric patients with localized brain tumors

PURPOSE

Growth hormone deficiency (GHD) after radiation therapy negatively affects growth and development and quality of life in children with brain tumors.

PATIENTS AND MATERIALS

Between 1997 and 2008, 192 pediatric patients with localized primary brain tumors (ependymoma, n = 88; low-grade glioma, n = 51; craniopharyngioma, n = 28; high-grade glioma, n = 23; and other tumor types, n = 2) underwent provocative testing of GH secretion by using the secretogogues arginine and L-dopa before and after (6, 12, 36, and 60 months) conformal radiation therapy (CRT). A total of 664 arginine/l-dopa test procedures were performed.

RESULTS

Baseline testing revealed preirradiation GHD in 22.9% of tested patients. On the basis of data from 118 patients, peak GH was modeled as an exponential function of time after CRT and mean radiation dose to the hypothalamus. The average patient was predicted to develop GHD with the following combinations of the time after CRT and mean dose to the hypothalamus: 12 months and more than 60 Gy; 36 months and 25 to 30 Gy; and 60 months and 15 to 20 Gy. A cumulative dose of 16.1 Gy to the hypothalamus would be considered the mean radiation dose required to achieve a 50% risk of GHD at 5 years (TD(50/5)).

CONCLUSION

GH secretion after CRT can be predicted on the basis of dose and time after irradiation in pediatric patients with localized brain tumors. These findings provide an objective radiation dose constraint for the hypothalamus.

Pegylated long-acting human growth hormone possesses a promising once-weekly treatment profile, and multiple dosing is well tolerated in adult patients with growth hormone deficiency

BACKGROUND

Recombinant human GH (rhGH) replacement therapy in children and adults currently requires daily sc injections for several years or lifelong, which may be both inconvenient and distressing for patients. NNC126-0083 is a pegylated rhGH developed for once-weekly administration.

OBJECTIVES

Our objective was to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of multiple doses of NNC126-0083 in adult patients with GH deficiency (GHD).

SUBJECTS AND METHODS

Thirty-three adult patients with GHD, age 20-65 yr, body mass index 18.5-35.0 kg/m(2), and glycated hemoglobin of 8.0% or below. Fourteen days before randomization, subjects discontinued daily rhGH. NNC126-0083 (0.01, 0.02, 0.04, and 0.08 mg/kg) was given sc once weekly for 3 wk (NNC126-0083 for six subjects and placebo for two subjects). Blood samples were collected up to 168 h after the first and up to 240 h after the third dosing. Physical examination, antibodies, and local tolerability were assessed.

RESULTS

NNC126-0083 was well tolerated with no difference in local tolerability compared with placebo and with no signs of lipoatrophy. A more than dose-proportional exposure was observed at the highest NNC126-0083 dose (0.16 mg protein/kg). Steady-state pharmacokinetics seemed achieved after the second dosing. A clear dose-dependent pharmacodynamic response in circulating IGF-I levels was observed [from a predose mean (SD) IGF-I SD score of -3.2 (1.7) to peak plasma concentration of -0.5 (1.3), 1.6 (1.3), 2.1 (0.5), and 4.4 (0.9) in the four dose groups, respectively].

CONCLUSION

After multiple dosing of NNC126-0083, a sustained pharmacodynamic response was observed. NNC126-0083 has the potential to serve as an efficacious, safe, and well-tolerated once-weekly treatment of adult patients with GHD.

Obesity, growth hormone and weight loss

Growth hormone (GH) is the most important hormonal regulator of postnatal longitudinal growth in man. In adults GH is no longer needed for longitudinal growth. Adults with growth hormone deficiency (GHD) are characterised by perturbations in body composition, lipid metabolism, cardiovascular risk profile and bone mineral density. It is well established that adult GHD usually is accompanied by an increase in fat accumulation and GH replacement in adult patients with GHD results in reduction of fat mass and abdominal fat mass in particular. It is also recognized that obesity and abdominal obesity in particular results in a secondary reduction in GH secretion and subnormal insulin-like growth factor-I (IGF-I) levels. The recovery of the GH IGF-I axis after weight loss suggest an acquired defect, however, the pathophysiologic role of GH in obesity is yet to be fully understood. In clinical studies examining the efficacy of GH in obese subjects very little or no effect are observed with respect to weight loss, whereas GH seems to reduce total and abdominal fat mass in obese subjects. The observed reductions in abdominal fat mass are modest and similar to what can be achieved by diet or exercise interventions.

Treatment of adult growth hormone deficiency: who, why and how? A review

Adult growth hormone deficiency (AGHD) is nowadays recognized as a distinct clinical entity and replacement therapy has become a standard practice. Reflecting on the accumulated evidence, questions nevertheless arise. Should all AGHD patients be treated? What dose of GH should be given and for how long? What are the real long-term benefits, in particular regarding life expectancy? if the diagnosis of severe GHD is firmly established and if there is no contra-indication (such as an active cancer or uncontrolled diabetes), it is worthwile initiating GH replacement therapy. Treatment can indeed correct the abnormal body composition, improve various adverse cardiovascular parameters and risk factors, increase muscle strength and bone mineral density and, although to a variable degree, improve the patient's quality of life and psychological well-being. Treatment should be started with very low doses to avoid side-effects related to fluid retention and should then be gradually titrated against IGF-I values, clinical response and individual tolerance.There is unfortunately no confirmed predictive factor for the overall therapeutic response in a given individual. Thus, the decision to whether or not pursue the therapy will depend on the ratio of perceived and expected benefits over cost and risks of treatment, as well as on the persistent motivation of the patient.

Disturbance of the growth hormone-insulin-like growth factor-1 axis associated with poor performance status in patients with solid tumors

OBJECTIVE

Hormonal imbalance characterized by excessive production of growth hormone (GH) and a low circulating concentration of insulin-like growth factor (IGF)-1 has been demonstrated in individuals with various serious conditions. However, little is known about changes in the GH-IGF-1 axis in cancer patients.

METHODS

We prospectively examined the circulating levels of several hormones in 58 patients with solid tumors who were classified according to Eastern Cooperative Oncology Group performance status (PS): PS 0-1, n = 15; PS 2, n = 15; PS 3, n = 15; and PS 4, n = 13. The relations of hormone concentrations, with a focus on the GH-IGF-1 system, to PS were evaluated by Spearman's rank correlation test and regression analysis.

RESULTS

The circulating levels of IGF-1, IGF-binding protein-3 and thyroid hormones (total T(3) and T(4)) were inversely correlated with PS score. The concentration of GH was increased irrespective of PS but not statistically significant. The ratio of IGF-I to GH was inversely correlated with PS. The levels of GH and IGF-1 in all patients were also inversely correlated.

CONCLUSIONS

The present study suggests that the GH-IGF-1 axis is disturbed in patients with cancer.

Pharmacological and physiological growth hormone stimulation tests to predict successful GH therapy in children

Although the current use of growth hormone (GH) stimulation tests (GHSTs) is still subject to debate, the tests are widely used to diagnose GH deficiency. This literature review evaluates primarily the sensitivity, specificity and reliability of GHSTs and secondarily their convenience. Single pharmacological tests typically address only a single pathway in the complex physiological regulation of GH secretion and are therefore characterized by lower sensitivity, specificity and reliability than combined pharmacological tests or physiological tests. In spite of the high levels of sensitivity, specificity and reliability, physiological tests require considerably more effort to perform, from the physician as well as from the child. Therefore, a need for an alternative, convenient, physiological GHST still remains. Oral ingestion of dietary protein is convenient in practice and may induce more physiological stimulation of GH secretion, hence may be a promising valuable addition to the existing GHSTs in GH deficiency.

Disruption of growth hormone receptor prevents calorie restriction from improving insulin action and longevity

Most mutations that delay aging and prolong lifespan in the mouse are related to somatotropic and/or insulin signaling. Calorie restriction (CR) is the only intervention that reliably increases mouse longevity. There is considerable phenotypic overlap between long-lived mutant mice and normal mice on chronic CR. Therefore, we investigated the interactive effects of CR and targeted disruption or knock out of the growth hormone receptor (GHRKO) in mice on longevity and the insulin signaling cascade. Every other day feeding corresponds to a mild (i.e. 15%) CR which increased median lifespan in normal mice but not in GHRKO mice corroborating our previous findings on the effects of moderate (30%) CR on the longevity of these animals. To determine why insulin sensitivity improves in normal but not GHRKO mice in response to 30% CR, we conducted insulin stimulation experiments after one year of CR. In normal mice, CR increased the insulin stimulated activation of the insulin signaling cascade (IR/IRS/PI3K/AKT) in liver and muscle. Livers of GHRKO mice responded to insulin by increased activation of the early steps of insulin signaling, which was dissipated by altered PI3K subunit abundance which putatively inhibited AKT activation. In the muscle of GHRKO mice, there was elevated downstream activation of the insulin signaling cascade (IRS/PI3K/AKT) in the absence of elevated IR activation. Further, we found a major reduction of inhibitory Ser phosphorylation of IRS-1 seen exclusively in GHRKO muscle which may underpin their elevated insulin sensitivity. Chronic CR failed to further modify the alterations in insulin signaling in GHRKO mice as compared to normal mice, likely explaining or contributing to the absence of CR effects on insulin sensitivity and longevity in these long-lived mice.

Effect of dimethyl-beta-cyclodextrin concentrations on the pulmonary delivery of recombinant human growth hormone dry powder in rats

The aim of this article is to prepare and characterize inhalable dry powders of recombinant human growth hormone (rhGH), and assess their efficacy for systemic delivery of the protein in rats. The powders were prepared by spray drying using dimethyl-beta-cyclodextrin (DMbetaCD) at different molar ratios in the initial feeds. Size exclusive chromatography was performed in order to determine protecting effect of DMbetaCD on the rhGH aggregation during spray drying. By increasing the concentration of DMbetaCD, rhGH aggregation was decreased from 9.67 (in the absence of DMbetaCD) to 0.84% (using DMbetaCD at 1000 molar ratio in the spray solution). The aerosol performance of the spray dried (SD) powders was evaluated using Andersen cascade impactor. Fine particle fraction values of 53.49%, 33.40%, and 23.23% were obtained using DMbetaCD at 10, 100, and 1000 molar ratio, respectively. In vivo studies showed the absolute bioavailability of 25.38%, 76.52%, and 63.97% after intratracheal insufflation of the powders produced after spray drying of the solutions containing DMbetaCD at 10, 100, and 1000 molar ratio, respectively in rat. In conclusion, appropriate cyclodextrin concentration was achieved considering the protein aggregation and aerosol performance of the SD powders and the systemic absorption following administration through the rat lung.