Growth hormone therapy

Height outcomes in Korean children with idiopathic short stature receiving growth hormone treatment

Objectives

Growth hormone (GH) therapy's capacity to increase height velocity and height at the end of the study in children with idiopathic short stature (ISS) is controversial. We aimed to investigate the height standard deviation score (SDS) and height velocity of patients with ISS in Korea who received GH treatment.

Methods

We retrospectively reviewed and performed linear mixed model and survival analyses on data from 12 tertiary hospitals in Korea, including subjects diagnosed with ISS from January 2009 to September 2019, treated with GH therapy for more than 6 months, and who were at a pre-pubertal state at the time of diagnosis.

Results

We included 578 children (330 boys and 248 girls). The mean daily dose of GH in this study was 0.051 mg/kg, which was lower than the approved dose in Korea of 0.062 - 0.067 mg/kg. Height SDS was higher in patients who started treatment before the age of 6 years. The probability of reaching the target SDS (-1 SDS) from the beginning of treatment to 2-3 years after its start was higher in children starting treatment before the age of 6 years. The hazard ratio to reach the target SDS (-1 SDS) when using automatic pen or electronic devices was 1.727 times higher than that when using the needle and syringe device.

Conclusion

ISS patients should start GH treatment at an early age, and even lower-than-recommended drug doses may be effective. The selection of automatic pen or electronic device can have a positive effect on reaching the target height SDS.

Gender-Dependent Growth and Insulin-Like Growth Factor-1 Responses to Growth Hormone Therapy in Prepubertal Growth Hormone-Deficient Children

Gender seems to be an important factor influencing the response to recombinant human growth hormone (rhGH) therapy in GH-deficient adolescents and adults. The results of studies evaluating gender-specific response to rhGH therapy in prepubertal GH-deficient children are divergent. The aim of this study was to determine the effect of gender on the growth and insulin-like growth factor-1 (IGF-1) responses in 75 prepubertal GH-deficient children during the first 2 years of rhGH therapy. There were no baseline gender differences in age, bone age, anthropometrical parameters, and IGF-1 SDS for bone age. After the initiation of rhGH therapy, there were no gender-specific differences concerning the reduction of height deficit. Serum IGF-1 levels were higher in the prepubertal GH-deficient girls than in the age-matched boys, but the difference was not significant when expressed as IGF-1 SDS for bone age. The increase in IGF-1 SDS for bone age was significantly greater in girls versus boys after the first 6 months of therapy, comparable between girls and boys after the first year of therapy, and tended to be higher in boys after the second year of therapy. In conclusion, prepubertal GH-deficient girls and boys do not differ significantly in growth response in the first 2 years of rhGH therapy.

Iontophoretic Transdermal Delivery of Human Growth Hormone (hGH) and the Combination Effect of a New Type Microneedle, Tappy Tok Tok®

Transdermal drug administration presents several advantages and it is therefore favorable as an alternative drug delivery route. However, transdermal delivery of biopharmaceutical drugs is made difficult by the skin barrier. Microneedle application and iontophoresis are strategies which can be used to overcome this barrier. Therefore, recombinant human growth hormone (rhGH) was used as a model macromolecular drug and was transdermally delivered using microneedle application and iontophoresis. Methylene blue staining, stereomicroscopy and scanning electron microscope (SEM) imaging were used to characterize the microchannels produced. To optimize the iontophoresis protocol, the effects of molecular charge and current density on transdermal delivery were evaluated in an in vitro permeation study using excised rat skin tissues. Using the optimized iontophoresis protocol, the combination effects of iontophoretic delivery via microchannels were evaluated in three different experimental designs. The flux obtained with anodal iontophoresis in citrate buffer was approximately 10-fold higher that that with cathodal iontophoresis in phosphate buffered saline (PBS). Flux also increased with current density in anodal iontophoresis. The combination of iontophoresis and microneedle application produced higher flux than single application. These results suggest that anodal iontophoresis with higher current density enhances the permeation of macromolecules through microchannels created by microneedles. In conclusion, the combination of iontophoresis and microneedles is a potential strategy for the enhancement of transdermal delivery of macromolecular drugs.

Medicalising short children with growth hormone? Ethical considerations of the underlying sociocultural aspects

In 2003, the Food and Drug Administration approved the use of growth hormone treatment for idiopathic short stature children, i.e. children shorter than average due to an unknown medical cause. Given the absence of any pathological conditions, this decision has been contested as a case of medicalisation. The aim of this paper is to broaden the debate over the reasons for and against the treatment, to include considerations of the sociocultural phenomenon of the medicalisation of short stature, by means of a critical understanding of the concept of medicalisation. After defining my understanding of medicalisation and describing both the treatment and the condition of idiopathic short stature, I will problematise two fundamental issues: the medical/non-medical distinction and the debate about the goals of medicine. I will analyse them, combining perspectives of bioethics, medical sociology, philosophy of medicine and medical literature, and I will suggest that there are different levels of normativity of medicalisation. Ultimately, this study shows that: (1) the definition of idiopathic short stature, focusing only on actual height measurement, does not provide enough information to assess the need for treatment or not; (2) the analysis of the goals of medicine should be broadened to include justifications for the treatment; (3) the use of growth hormone for idiopathic short stature involves strong interests from different stakeholders. While the treatment might be beneficial for some children, it is necessary to be vigilant about possible misconduct at different levels of medicalisation.

Growth hormone - past, present and future

Growth hormone (GH) research and its clinical application for the treatment of growth disorders span more than a century. During the first half of the 20th century, clinical observations and anatomical and biochemical studies formed the basis of the understanding of the structure of GH and its various metabolic effects in animals. The following period (1958-1985), during which pituitary-derived human GH was used, generated a wealth of information on the regulation and physiological role of GH - in conjunction with insulin-like growth factors (IGFs) - and its use in children with GH deficiency (GHD). The following era (1985 to present) of molecular genetics, recombinant technology and the generation of genetically modified biological systems has expanded our understanding of the regulation and role of the GH-IGF axis. Today, recombinant human GH is used for the treatment of GHD and various conditions of non-GHD short stature and catabolic states; however, safety concerns still accompany this therapeutic approach. In the future, new therapeutics based on various components of the GH-IGF axis might be developed to further improve the treatment of such disorders. In this Review, we describe the history of GH research and clinical use with a particular focus on disorders in childhood.

Selection for growth rate and body size have altered the expression profiles of somatotropic axis genes in chickens

The growth hormone / insulin-like growth factor-1 (GH/IGF-1) pathway of the somatotropic axis is the major controller for growth rate and body size in vertebrates, but the effect of selection on the expression of GH/IGF-1 somatotropic axis genes and their association with body size and growth performance in farm animals is not fully understood. We analyzed a time series of expression profiles of GH/IGF-1 somatotropic axis genes in two chicken breeds, the Daweishan mini chickens and Wuding chickens, and the commercial Avian broilers hybrid exhibiting markedly different body sizes and growth rates. We found that growth rate and feed conversion efficiency in Daweishan mini chickens were significantly lower than those in Wuding chickens and Avian broilers. The Wuding and Daweishan mini chickens showed higher levels of plasma GH, pituitary GH mRNA but lower levels of hepatic growth hormone receptor (GHR) mRNA than in Avian broilers. Daweishan mini chickens showed significantly lower levels of plasma IGF-1, thigh muscle and hepatic IGF-1 mRNA than did Avian broilers and Wuding chickens. These results suggest that the GH part of the somatotropic axis is the main regulator of growth rate, while IGF-1 may regulate both growth rate and body weight. Selection for growth performance and body size have altered the expression profiles of somatotropic axis genes in a breed-, age-, and tissue-specific manner, and manner, and alteration of regulatory mechanisms of these genes might play an important role in the developmental characteristics of chickens.

Comparison of body surface area versus weight-based growth hormone dosing for girls with Turner syndrome

BACKGROUND/AIMS

Growth Hormone (GH) dosage in childhood is adjusted for body size, but there is no consensus whether body weight (BW) or body surface area (BSA) should be used. We aimed at comparing the biological effect and cost-effectiveness of GH treatment dosed per m2 BSA in comparison with dosing per kg BW in girls with Turner syndrome (TS).

METHODS

Serum IGF-I, GH dose, and adult height gain (AHG) from girls participating in two Dutch and five Swedish studies on the efficacy of GH were analyzed, and the cumulative GH dose and costs were calculated for both dose adjustment methods. Additional medication included estrogens (if no spontaneous puberty occurred) and oxandrolone in some studies.

RESULTS

At each GH dose, the serum IGF-I standard deviation score remained stable over time after an initial increase after the start of treatment. On a high dose (at 1 m2 equivalent to 0.056-0.067 mg/kg/day), AHG was at least equal on GH dosed per m2 BSA compared with dosing per kg BW. The cumulative dose and cost were significantly lower if the GH dose was adjusted for m2 BSA.

CONCLUSION

Dosing GH per m2 BSA is at least as efficacious as dosing per kg BW, and is more cost-effective.

Towards optimal treatment with growth hormone in short children and adolescents: evidence and theses

Treatment with growth hormone (GH) has become standard practice for replacement in GH-deficient children or pharmacotherapy in a variety of disorders with short stature. However, even today, the reported adult heights achieved often remain below the normal range. In addition, the treatment is expensive and may be associated with long-term risks. Thus, a discussion of the factors relevant for achieving an optimal individual outcome in terms of growth, costs, and risks is required. In the present review, the heterogenous approaches of treatment with GH are discussed, considering the parameters available for an evaluation of the short- and long-term outcomes at different stages of treatment. This discourse introduces the potential of the newly emerging prediction algorithms in comparison to other more conventional approaches for the planning and evaluation of the response to GH. In rare disorders such as those with short stature, treatment decisions cannot easily be deduced from personal experience. An interactive approach utilizing the derived experience from large cohorts for the evaluation of the individual patient and the required decision-making may facilitate the use of GH. Such an approach should also lead to avoiding unnecessary long-term treatment in unresponsive individuals.

A review of guidelines for use of growth hormone in pediatric and transition patients

Growth hormone (GH) is approved by the US Food and Drug Administration (FDA) for use in pediatric patients with disorders of growth failure or short stature and in adults with growth hormone deficiency (GHD) and HIV/AIDS wasting and cachexia. For pediatric patients, guidelines for the use of GH have been developed by several organizations that have identified specific criteria for initiating GH therapy for each FDA-approved indication. Guidelines for adults have also been developed and include recommendations for transition (adolescent) patients with GHD. These patients are often treated with GH as children but may require continued treatment as young adults to attain full skeletal mineralization and improve cardiovascular risk factors. Adult and pediatric guidelines are supported by efficacy and safety studies, which show that, when started at an early age, GH treatment can increase growth velocity and that GH is safe and well-tolerated. We summarize the guidelines that are available for all FDA-approved indications among pediatric and transition patients. Adherence to these guidelines will help to ensure that patients with disorders of growth failure or short stature receive the necessary therapy to increase linear growth and transition smoothly to healthy adulthood.

Growth hormone: health considerations beyond height gain

The therapeutic benefit of growth hormone (GH) therapy in improving height in short children is widely recognized; however, GH therapy is associated with other metabolic actions that may be of benefit in these children. Beneficial effects of GH on body composition have been documented in several different patient populations as well as improvements in lipid profile. Marked augmentation of bone mineral density also seems evident in many pediatric populations. Some of these benefits may require continued therapy past the acquisition of adult height. With long-term therapy of any kind, the adverse consequences of treatment should also be considered. Fortunately, long-term GH treatment seems to be safe and well-tolerated. This review describes the long-term metabolic effects of GH treatment in the pediatric population and considers how these may benefit children who are treated with GH.

The common exon 3 polymorphism of the growth hormone receptor gene and the effect of growth hormone therapy on growth in Korean patients with Turner syndrome

OBJECTIVE

Recombinant human growth hormone (GH) can achieve final adult height gain in girls with Turner syndrome (TS), but its efficacy varies widely across individuals. The exon 3-deleted polymorphism of growth hormone receptor (d3-GHR) has been reported to be associated with responsiveness to GH therapy. The short-term growth response of Turner patients to GH therapy was analysed according to their GHR-exon 3 polymorphism genotype.

DESIGN AND PATIENTS

This was a retrospective study of 175 TS patients. Auxological and endocrine parameters were measured, and the GHR-exon 3 genotype was analysed. Allelic frequencies of GHR-exon 3 genotype were compared between patients with TS and control individuals. GH had been administered to 147 patients, 115 of which remained pre-pubertal after the first follow-up year. Changes in height standard deviation score (SDS), height velocity (HV), body mass index (BMI), IGF-1 and IGF binding protein-3 (IGFBP-3) concentrations were compared between these patients, grouped according to genotype, after the first follow-up year.

RESULTS

There was no difference in GHR-exon 3 genotype frequency between the TS and control groups of Koreans. According to the GHR-exon 3 genotype (fl/fl group vs. d3/fl and d3/d3 group), HV gain and height SDS gain did not differ significantly at the first year of GH therapy. Moreover, changes in IGF-1, IGFBP-3 concentration and BMI showed no significant difference between the groups with and without d3-GHR after 1 year of GH therapy.

CONCLUSION

The distribution of the GHR-exon 3 genotype was similar in the TS and control groups in a Korean population. The growth promotion efficacy of GH therapy did not differ significantly between TS patients with and without the d3-GHR allele. These findings indicate that the GHR-exon 3 genotype may not be a major factor to affect the GH response in Korean Turner patients.

Common exon 3 polymorphism of the GH receptor (GHR) gene and effect of GH therapy on growth in Korean children with idiopathic short stature (ISS)

OBJECTIVE

A human GH receptor (GHR) gene exon 3 polymorphism (d3-GHR) has been reported to be associated with responsiveness to GH therapy. We assessed the frequencies of this polymorphism in Korean control and idiopathic short stature (ISS) populations, and analysed short-term growth response to GH therapy according to GHR-exon 3 genotypes in Korean children with ISS.

DESIGN AND PATIENTS

This was a retrospective study in 158 ISS children. Auxological and endocrine parameters were measured, and the GHR-exon 3 genotype was analysed. Allelic frequencies of GHR-exon 3 genotype were compared between the ISS group and a control group. GH had been administered for 62 patients, 52 of whom remained prepubertal after the first follow-up year. Changes in height velocity (HV) and IGF-1 and IGFBP-3 concentrations following GH therapy were compared in patients with these genotypes.

RESULTS

There was no difference in GHR-exon 3 genotype frequency between ISS and control groups of Koreans. However, the fl/fl genotype was more frequent in Koreans than in Caucasians. ISS children with d3-GHR showed a significantly higher increment in HV (P = 0.002) and a marginally significant increment in IGF-1 concentration (P = 0.064) at the first year of GH therapy.

CONCLUSION

fl-GHR was more frequently detected in a Korean population than in Caucasians. The growth promotion efficacy of GH therapy differed significantly between ISS patients with and without the d3-GHR allele. These findings indicate that the GHR-exon 3 polymorphism can affect the growth promoting efficacy of short-term GH therapy in Korean children with ISS.

Long-term psychosocial consequences of hormone treatment for short stature

AIM

To examine psychosocial functioning of young adults with idiopathic short stature or short stature born small for gestational age after growth hormone (GH) and gonadotropin-releasing hormone agonist (GnRHa) treatment in early adolescence or no intervention.

METHODS

Thirty young adults (18 treated, 12 untreated; age 17-23 years; on average 5.5 years after the end of treatment) completed questionnaires regarding perceived competence and psychological distress. They and their parents were interviewed on social circumstances, height-related psychosocial stressors and parental worries about prospects in society.

RESULTS

Height gain was on average 2.3 cm more for the treated than for the untreated group. On none of the psychosocial variables differences were found between treated and untreated participants. Compared to Dutch population norms, psychological and social functioning was normal.

CONCLUSION

GH/GnRHa treatment, with arrest of pubertal development and lower than expected effects on final height, is not observed to lead to long-term negative or positive effects. Both treated and untreated participants go well through the psychosocial transition period of young adulthood. This suggests that, in the long term and independent of hormone treatment, adequate psychosocial adjustment is expected in case of short stature.

Craniofacial growth in growth hormone-deficient rats after growth hormone supplementation

INTRODUCTION

Growth hormone (GH) supplementation is an established therapy to increase stature in GH-deficient or short-for-age children, but comparatively little is known of its effects on the craniofacial skeleton.

METHODS

Using a mutant strain of Lewis rats (dw/dw) in which GH levels were 6% to 10% of normal, but other trophic hormones were unaffected, we investigated the differential susceptibility of craniofacial measures to GH supplementation, characterized their potential for partial or complete catch-up growth, and compared their growth changes with those in long bones. At 24 days of age and for 3 subsequent weeks, radiographs of the lateral head, upper limb, and lower limb were obtained from 3 groups of growing rats (n = 8-9 in each group): dwarf (experimental) with GH injection, dwarf (sham) with vehicle injection, and wild type (control) with vehicle injection. The x-ray images were scanned, standardized points digitized, and linear distances measured. Absolute growth curves were generated for each group by using multilevel modeling procedures and iterative generalized least-squares curve fitting.

RESULTS

For every measure, growth differences were evident between the experimental and the sham groups, but the treatment effect varied inversely with relative maturity of the measure. Although all craniofacial measures showed some catch-up growth, only 31% of craniofacial measures had complete catch-up compared with all limb measures. The percentage of catch-up varied inversely with relative maturity of the measure. Our results suggest that the effects of GH supplementation vary considerably, so that measures with the lowest relative maturity (greatest baseline potential) show the greatest treatment effect and catch-up, whereas more mature measures show less growth response to GH replacement.

CONCLUSIONS

These results suggest that, depending on the timing of GH supplementation, there is potential for change in proportions or shape of the craniofacial complex.

Growing up with idiopathic short stature: psychosocial development and hormone treatment; a critical review

To facilitate decisions on interventions in medically referred children with idiopathic short stature, the research on psychosocial functioning of these children, possible risk and protective factors influencing adaptation, and effects of hormone treatment were reviewed. Parents ranked the behaviour of their children on average between normal and below normal. The magnitude of these deviations varied from small to large. Little is known about the children's self-perceived psychosocial functioning. Some risk factors were found: being teased, being juvenilised, being a boy, having a younger but taller sibling, low intelligence, and low socioeconomic status. There have been few studies on the impact of protective factors including temperament, coping strategies, and social support. On average, hormone treatment did not improve psychosocial functioning. The research shows the advantages and disadvantages of hormone treatment that must be considered when choosing a suitable intervention. It is suggested that psychosocial adjustment can be improved by focusing on factors other than height alone.

Cost-utility of somatropin (rDNA origin) in the treatment of growth hormone deficiency in children

OBJECTIVE

The objective of this study was to generate estimates of cost-effectiveness/utility of somatropin (rDNA origin) in the treatment of growth hormone deficiency (GHD) in children.

METHODS

A decision-analytic model of the epidemiology and treatment of GHD in children was developed. Treatment of GHD was assessed in two hypothetical cohorts compared to no treatment--treatment with somatropin 0.030 mg/kg/day from ages 5 to 16 years, and treatment from ages 3 to 18 years. Costs (stated in 2005 US$) included those related to drug acquisition, endocrinologist consultations, and primary care office visits. Estimates of patient weight by age and sex were derived from published literature, as was the proportion of patients achieving normal height through somatropin treatment and pre/post-treatment patient utilities. Cost-effectiveness/utility was estimated over patients' expected lifetimes, and was stated alternatively as discounted (3% per annum) US dollars per normal height year (NHY) gained, and cost per quality adjusted life-year (QALY) gained. Multivariate sensitivity analyses were conducted to ensure robustness of the model.

RESULTS

The cost-effectiveness and cost-utility of treating children from ages 5 to 16 years with somatropin was estimated at approximately $8,900 per NHY gained and $37,000 per QALY gained, respectively. Corresponding ratios pertaining to treatment of children from ages 3 to 18 years were $9,300 per NHY gained and $42,600 per QALY gained. Findings were relatively insensitive to variation in most model parameters.

CONCLUSIONS

For both age cohorts, the cost-effectiveness/utility of somatropin in the treatment of GHD compares favorably to well-accepted threshold values. The use of somatropin represents reasonable value for money for the treatment of GHD in children.

GH1 splicing is regulated by multiple enhancers whose mutation produces a dominant-negative GH isoform that can be degraded by allele-specific small interfering RNA (siRNA)

The majority of mutations that cause isolated GH deficiency type II affect splicing of GH1 transcripts, leading to the production of a dominant-negative GH isoform. Because numerous mutations and polymorphisms throughout the GH1 gene have not yet been tested for aberrant splicing, we used a deletion mutagenesis screen across intron 2-exon 3-intron 3 to identify splicing regulatory sequences. These analyses identified a new enhancer element, ESE2, upstream of the cryptic splice site in exon 3 and further defined a previously described enhancer (ESE1) to include the first seven nucleotides of exon 3. Besides enhancers, the overall size of intron 3 is also crucial for exon inclusion. Given the deleterious effects of the dominant-negative 17.5-kDa isoform, these and previous studies underscore the extent to which splicing regulatory elements serve to prevent exon skipping. Importantly, we show here that small interfering RNAs can be used to specifically degrade exon 3-skipped transcripts, potentially a new avenue of therapeutic intervention in isolated GH deficiency II and other dominant disorders.

Growth hormone and exercise tolerance in patients with cystic fibrosis

Cystic fibrosis (CF) is a life-limiting inherited disorder characterised by pulmonary disease, pancreatic dysfunction and symptoms of malnutrition that are all interrelated with low exercise capacity and poor survival rate. Therapy with growth hormone (GH) may improve the reduced dimensional and functional capacity associated with poor nutritional status and catabolism and therefore improve exercise tolerance, quality of life and survival rate in patients with CF. The literature about GH treatment and its effect on exercise tolerance are rather limited, not always consistent and methodological concerns restrict further analysis. GH treatment may have beneficial effects on both growth and exercise tolerance without serious complications in prepubertal children with CF. The observed dimensional changes of the muscular, cardiovascular and pulmonary system seem to improve aerobic exercise capacity and respiratory and peripheral muscle strength. The physiological background of the observed changes is not yet fully understood, therefore, larger-scale studies with an optimised design are required.

Advances in Growth Hormone Therapy: A New Registry Tool

Growth hormone (GH) deficiency is a rare condition, and physicians may lack clinical experience of its treatment. Despite evidence for the efficacy and tolerability of GH therapy, a substantial proportion of patients remain untreated. Registries and other large-scale databases are an important tool for expanding the evidence base for GH treatment. Since the mid-1980s, registries have provided data on important aspects of the safety and efficacy of GH treatment. Registries have also allowed pooling of data from patients with rare conditions that could otherwise not be recruited in sufficient numbers for clinical trials. Importantly for patients and their relatives, use of registry data has allowed the development of prediction models that indicate the likely outcomes of treatment. MEGHA (Metabolic Endocrinology and Growth Hormone Assessment) is a recently developed, observational database with a number of features not found in existing registries, including its use as a day-to-day clinical management tool, the ability to create individual sub-studies, direct comparison of personal data against the full database, and a particular focus on the transition from childhood to adulthood. This creative registry is a promising instrument for further research into GH-related disorders that will improve GH therapy and thus provide benefits for patients.