Growth hormone treatment in children: review of safety and efficacy

Near-Infrared Triggered Biodegradable Microneedle Patch for Controlled Macromolecule Drug Release

Transdermal drug delivery of macromolecule drugs attracts significant attention due to the advantage of convenience and biocompatibility. However, the practical usage of it is limited by the low delivery efficiency and poor drug absorption. To develop an efficient, safe, and controllable transdermal delivery method, the near-infrared (NIR) triggered calcium sulfate and gelatin biodegradable composite microneedle (MN) patches are developed. The MN patches are fabricated by polydimethylsiloxane (PDMS) molds, and the structure data can be adjusted by changing the molds. Such an MN patch can release both macro and micro molecule drugs. After loading with photothermal converter IR780, which can transfer energy of light to heat, the release of macromolecule drugs in MNs can be controlled by applying NIR irradiation. The control effect can be enhanced by spraying 1-tetradecanol (TD) coating and optimizing the ratio (weight) of gelatin and calcium sulfate to 2:6. Besides, the MN patch can deliver drugs through the skin barrier, and the process can be controlled by NIR. Moreover, the insulin-loaded MN patch exhibits some therapeutic effects on healthy mice. This work suggests that biodegradable MNs can achieve controllable drug delivery and potentially be applied in individual treatment via transdermal ingestion.

Evaluating the TUITEK® patient support program in supporting caregivers of children diagnosed with growth hormone deficiency in Argentina

Introduction

The appropriate use of recombinant human growth hormone (r-hGH) treatment provides an opportunity to improve growth outcomes among pediatric patients with growth hormone deficiency (GHD). However, a major challenge in clinical practice is to adequately recognize and address factors that negatively affect treatment adherence. TUITEK® patient support program (PSP) was designed to help caregivers of children diagnosed with GHD to personalize the care pathway, improve adherence, and achieve better outcomes. Effectiveness of TUITEK® PSP has been demonstrated previously in a smaller sample (n = 31) in Taiwanese population. Here, we present the results from Argentina.

Methods

TUITEK® PSP was piloted among 76 caregivers of children with GHD administering r-hGH using easypod™ (Merck KGaA, Darmstadt, Germany) auto-injector device in Argentina. Based on TUITEK® personalization questionnaire, caregivers were assigned to high- and low-risk groups across four categories that may influence adherence, including disease and treatment coherence (DTC), self-administration (SA), treatment-related anxiety (TRA), and emotional burden (EB). The caregivers who were included in atleast one high-risk group had the provision of telephone calls with a nurse practitioner every 2 weeks for 3 months. The Wilcoxon signed-rank test was employed to assess changes in questionnaire-based scoring patterns between baseline and follow-up evaluations.

Results

Statistically significant changes (p < 0.05) in questionnaire scores between baseline and follow-up evaluations were observed across the four categories. The mean/median DTC (n = 11) and SA (n = 23) scores changed from 2.45/3 and 2.17/2, respectively, to 4/4, with all the caregivers moving to low-risk group following program completion (100%) for both categories. The mean/median TRA score (n = 40) changed from 3.58/3 to 2.5/2 and 67.5% of patients (27/40) moved to low-risk group. The mean/median EB score (n = 32) changed from 3.69/3 to 3.13/3 however, none of the caregivers moved to low-risk group (0%).

Conclusion

TUITEK® PSP is a simple, practical, and time-efficient interventional tool that can be used to address key adherence-related issues among caregivers of children with GHD and provide personalized adherence support. Our findings demonstrate that TUITEK® PSP has the potential to improve treatment adherence and self-management, thereby improving growth outcomes in Argentina.

Epidemiology of Disorders Associated with Short Stature in Childhood: A 20-Year Birth Cohort Study in Finland

Background

Many primary and secondary disorders disturb growth and cause short stature (height below −2 SDS) in childhood. Growth monitoring programs aim at their early detection but are not evidence-based: epidemiology of childhood growth disorders is poorly characterized, and no consensus exists on priority target conditions. Herein, we describe population-based epidemiological data on several primary and secondary growth disorders associated with short stature in childhood.

Materials and Methods

This retrospective population-based 20-year birth cohort study examined 1 144 503 children (51% boys) born in Finland between 1998 and 2017, with 16.5 million care notifications including medical diagnoses. The first occurrences of key primary or secondary growth disorders were identified in multiple registers. Median ages at diagnosis (MAD), and age- and sex-specific cumulative incidences (CMI) from birth until 16 years of age were determined.

Results

Turner syndrome was the most common primary growth disorder (CMI 52 per 100 000 at 16 years, MAD 4.0 years). Most primary growth disorders were diagnosed before the age of 4 years, and thereafter, secondary growth disorders increased in number. MAD of growth hormone deficiency (GHD) was 8.7 (boys) and 7.2 years (girls). At 16 years, the CMI of GHD was higher in boys than in girls (127 versus 93 per 100 000, respectively), whereas the CMI of hypothyroidism was higher in girls (569 versus 306 per 100 000). Celiac disease was the most common secondary growth disorder and more common in girls than in boys (988 versus 546 per 100 000 at 16 years, respectively).

Conclusion

These population-based epidemiological data indicate that childhood growth monitoring should be age- and sex-specific. In the early childhood, the focus should be on primary growth disorders, and from preschool age also on secondary growth disorders. These results provide evidence for improving growth monitoring programs and diagnostic practices targeting on Turner syndrome, GHD, hypothyroidism, and celiac disease.

Investigating the Impact of the TUITEK® Patient Support Programme, Designed to Support Caregivers of Children Prescribed Recombinant Human Growth Hormone Treatment in Taiwan

PURPOSE

Poor adherence to recombinant human growth hormone (r-hGH) treatment presents a significant barrier to achieving optimal growth outcomes. It is important to identify and address the treatment adherence-related needs of children prescribed r-hGH treatment, and develop new approaches to improve adherence. We aimed to measure the impact of the TUITEK^® patient support programme, a multi-component personalized service intervention, on caregivers' knowledge, beliefs, and perceptions of short stature and adherence to its treatment.

PATIENTS AND METHODS

The evaluation of the TUITEK^® patient support programme was conducted among 31 caregivers of children with short stature and receiving r-hGH treatment via the easypod™ auto-injector device in Taiwan. Caregivers within the 'high risk' category for knowledge, beliefs and perception factors influencing adherence to r-hGH treatment (disease and treatment coherence, emotional burden, self-administration, and treatment-related anxiety) were identified via the TUITEK^® personalization questionnaire and followed up with bi-weekly telephone calls by a nurse practitioner over a 3-month period. A Wilcoxon signed-rank test was used to compare changes in questionnaire-based scoring patterns between baseline and follow-up.

RESULTS

Between baseline and follow-up, the percentage of caregivers scoring as 'high risk' for emotional burden reduced by 37%; there was an improvement in confidence of self-administration by 57% and the percentage of caregivers scoring as 'high risk' for treatment-related anxiety reduced by 52%. At follow-up, all caregivers classified as 'high risk' within the disease and treatment coherence item at baseline moved into the 'low risk' category. Statistically significant changes in questionnaire scores between baseline and follow-up for disease and treatment understanding, emotional burden, self-administration, and treatment-related anxiety were also observed.

CONCLUSION

These findings indicate that the TUITEK^® patient support programme can positively address disease and treatment-related barriers amongst caregivers regarding optimal adherence of their children to r-hGH treatment, which has the potential to positively impact on adherence levels and patient clinical health outcomes.

Weekly Lonapegsomatropin in Treatment-Naïve Children With Growth Hormone Deficiency: The Phase 3 heiGHt Trial

CONTEXT

For children with growth hormone deficiency (GHD), treatment burden with daily somatropin injections [human growth hormone (hGH)] is high, which may lead to poor adherence and suboptimal overall treatment outcomes. Lonapegsomatropin (TransCon hGH) is an investigational long-acting, once-weekly prodrug for the treatment of GHD.

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of once-weekly lonapegsomatropin vs daily somatropin.

DESIGN

The heiGHt trial was a randomized, open-label, active-controlled, 52-week Phase 3 trial (NCT02781727).

SETTING

This trial took place at 73 sites across 15 countries.

PATIENTS

This trial enrolled and dosed 161 treatment-naïve, prepubertal patients with GHD.

INTERVENTIONS

Patients were randomized 2:1 to receive lonapegsomatropin 0.24 mg hGH/kg/week or an equivalent weekly dose of somatropin delivered daily.

MAIN OUTCOME MEASURE

The primary end point was annualized height velocity (AHV) at week 52. Secondary efficacy end points included change from baseline in height SD scores (SDS).

RESULTS

Least squares (LS) mean (SE) AHV at 52 weeks was 11.2 (0.2) cm/year for lonapegsomatropin vs 10.3 (0.3) cm/year for daily somatropin (P = 0.009), with lonapegsomatropin demonstrating both noninferiority and superiority over daily somatropin. LS mean (SE) height SDS increased from baseline to week 52 by 1.10 (0.04) vs 0.96 (0.05) in the weekly lonapegsomatropin vs daily somatropin groups (P = 0.01). Bone age/chronological age ratio, adverse events, tolerability, and immunogenicity were similar between groups.

CONCLUSIONS

The trial met its primary objective of noninferiority in AHV and further showed superiority of lonapegsomatropin compared to daily somatropin, with similar safety, in treatment-naïve children with GHD.

Pharmacogenomics applied to recombinant human growth hormone responses in children with short stature

We present current knowledge concerning the pharmacogenomics of growth hormone therapy in children with short stature. We consider the evidence now emerging for the polygenic nature of response to recombinant human growth hormone (r-hGH). These data are related predominantly to the use of transcriptomic data for prediction. The impact of the complex interactions of developmental phenotype over childhood on response to r-hGH are discussed. Finally, the issues that need to be addressed in order to develop a clinical test are described.

A microneedle platform for buccal macromolecule delivery

Alternative means for drug delivery are needed to facilitate drug adherence and administration. Microneedles (MNs) have been previously investigated transdermally for drug delivery. To date, drug loading into MNs has been limited by drug solubility in the polymeric blend. We designed a highly drug-loaded MN patch to deliver macromolecules and applied it to the buccal area, which allows for faster delivery than the skin. We successfully delivered 1-mg payloads of human insulin and human growth hormone to the buccal cavity of swine within 30 s. In addition, we conducted a trial in 100 healthy volunteers to assess potential discomfort associated with MNs when applied in the oral cavity, identifying the hard palate as the preferred application site. We envisage that MN patches applied on buccal surfaces could increase medication adherence and facilitate the painless delivery of biologics and other drugs to many, especially for the pediatric and elderly populations.

Systematic profiling of clinical missence mutation effects on the intermolecular interaction between human growth hormone and its receptor in isolated growth hormone deficiency

Isolated growth hormone deficiency (IGHD) is the most common pituitary hormone deficiency and can result from congenital or acquired causes. Among the known factors, genetic mutations in human growth hormone (hGH) remain the most frequent cause of IGHD, which influence the binding of hGH to its cognate receptor (hGHbp). Although previous studies have systematically investigated the residue importance at hGH-hGHbp complex interface, the molecular role of IGHD-associated residue mutations in the complex function still remains largely unexplored. Here, a total of 21 known hGH naturally-occurring missence mutations that have been clinically observed to be involved in IGHD disorder are collected and confirmed by original literature; they effects on the conformation, energetics and dynamics of hGH-hGHbp recognition and interaction are dissected at molecular level by using atomistic dynamics simulations, binding energy calculations and fluorescence spectroscopy assays. A systematic profile of hGH-hGHbp binding response to these clinical missence mutations is created, based on which it is revealed that (i) most mutations have appreciably unfavorable effect on the binding, which potentially destabilize the complex interaction, while only very few are predicted as moderate stabilizers for the complex system, and (ii) these disease-related mutations can locate either at complex interface or in hGH protein interior far away from the interface; both can influence the complex binding through either direct interaction or indirect allostericity. Two mutations, E100K (non-interface) and G146R (interface), are identified to address potent destabilization effect on hGH-hGHbp complex system; they can reduce the complex binding affinity by 8-fold (K_d changes from 0.76 to 5.9 nM) and 46-fold (K_d changes from 0.76 to 34.7 nM), respectively.

IGF-1/GH axis enhances losartan treatment in Lama2-related muscular dystrophy

As the complexities of dystrophic pathology have been elucidated over the last few years, it has become increasingly clear that primary monogenetic defects result in multiple secondary pathologies capable of autonomously driving disease progression. Consequently, single-mode therapies fail to comprehensively ameliorate all aspects of pathology. Lama2-related muscular dystrophy (MDC1A) is a devastating congenital muscular dystrophy caused by mutations in the LAMA2 gene that results in multi-faceted secondary pathologies that include inflammation, fibrosis, apoptosis, and necrosis leading to severe muscle weakness and minimal postnatal growth. This study sought to implement a novel combinatorial treatment utilizing losartan, previously shown to ameliorate fibrosis and inflammation in conjunction with transgenic IGF-1 overexpression to improve postnatal growth. We found that dual-therapy rescued inflammation and fibrosis, improved weight gain, and led to remarkable restoration of muscle architecture and locomotory function in DyW mice (mouse model of MDC1A). We further showed using murine growth hormone that postnatal intervention with both therapies also yielded impressive amelioration of dystrophic pathology. Our results suggest for the first time that a combinatorial anti-fibrotic and pro-myogenic therapy could be the foundation of future therapies to a population of afflicted children in serious need.

Endocrine disorders in Fanconi anemia: recommendations for screening and treatment

CONTEXT

Endocrine problems are common in patients with Fanconi anemia (FA). About 80% of children and adults with FA have at least one endocrine abnormality, including short stature, GH deficiency, abnormal glucose or insulin metabolism, dyslipidemia, hypothyroidism, pubertal delay, hypogonadism, or impaired fertility. The goal of this report is to provide an overview of endocrine abnormalities and guidelines for routine screening and treatment to allow early diagnosis and timely intervention.

EVIDENCE ACQUISITION

This work is based on a comprehensive literature review, including relevant articles published between 1971 and 2014, and proceedings of a Consensus Conference held by the Fanconi Anemia Research Fund in 2013.

EVIDENCE SYNTHESIS

The panel of experts collected published evidence and discussed its relevance to reflect current information about the endocrine care of children and adults with FA before the Consensus Conference and through subsequent deliberations that led to the consensus.

CONCLUSIONS

Individuals with FA should be routinely screened for endocrine abnormalities, including evaluation of growth; glucose, insulin, and lipid metabolism; thyroid function; puberty; gonadal function; and bone mineral metabolism. Inclusion of an endocrinologist as part of the multidisciplinary patient care team is key to providing comprehensive care for patients with FA.

Adherence to growth hormone therapy: a practical approach

BACKGROUND

Early detection of suspected poor adherence to growth hormone (GH) therapy is crucial to achieve normal final height in GH-deficient (GHD) patients.

PATIENTS

106 children (73 M, 33 F) with a median age of 10.47±3.48 years (mean±standard deviation score (SDS)) exhibited short stature (-1.76±0.64 SDS) and a delayed bone age (8.68±3.42 years). Severe GHD was found in 28, while partial GHD was seen in 78 cases, with low IGF-I values. Recombinant human GH was administered by daily subcutaneous injection at a dosage of 21 µg/kg in prepubertal and 25 µg/kg in pubertal patients.

RESULTS

Poor adherence was suspected in a number of patients, but clearly demonstrated in only 4 cases with persistent reduced height velocity in spite of a corrected therapeutic regimen. These patients admitted incomplete adherence to GH injections and clinical and anthropometric measurements revealed their poor response to therapy.

CONCLUSIONS

To efficaciously improve adherence in GHD patients, it is mandatory to regularly interview patients; a non-aggressive approach might be utilized to ensure effective communication with patients and their parents.

Growth hormone treatment enhances the functional recovery of sciatic nerves after transection and repair

INTRODUCTION

Although nerves can spontaneously regenerate in the peripheral nervous system without treatment, functional recovery is generally poor, and thus there is a need for strategies to improve nerve regeneration.

METHODS

The left sciatic nerve of adult rats was transected and immediately repaired by epineurial sutures. Rats were then assigned to one of two experimental groups treated with either growth hormone (GH) or saline for 8 weeks. Sciatic nerve regeneration was estimated by histological evaluation, nerve conduction tests, and rotarod and treadmill performance.

RESULTS

GH-treated rats showed increased cellularity at the lesion site together with more abundant immunoreactive axons and Schwann cells. Compound muscle action potential (CMAP) amplitude was also higher in these animals, and CMAP latency was significantly lower. Treadmill performance increased in rats receiving GH.

CONCLUSION

GH enhanced the functional recovery of the damaged nerves, thus supporting the use of GH treatment, alone or combined with other therapeutic approaches, in promoting nerve repair.

Treatment of short stature and growth hormone deficiency in children with somatotropin (rDNA origin)

Somatotropin (growth hormone, GH) of recombinant DNA origin has provided a readily available and safe drug that has greatly improved management of children and adolescents with GH deficiency (GHD) and other disorders of growth. In the US and Europe, regulatory agencies have given approval for the use of GH in children and adults who meet specific criteria. However, clinical and ethical controversies remain regarding the diagnosis of GHD, dosing of GH, duration of therapy and expected outcomes. Areas which also require consensus include management of pubertal patients, transitioning pediatric patients to adulthood, management of children with idiopathic short stature and the role of recombinant IGF-1 in treatment. Additionally, studies have demonstrated anabolic benefits of GH in children who have inflammatory-based underlying disease and efficacy of GH in overcoming growth delays in people treated chronically with corticosteroids. These areas are open for possible new uses of this drug. This review summarizes current indications for GH use in children and discusses areas of clinical debate and potential anabolic uses in chronic illness.

Identification of factors associated with good response to growth hormone therapy in children with short stature: results from the ANSWER Program®

OBJECTIVE

To identify factors associated with growth in children on growth hormone (GH) therapy using data from the American Norditropin Studies: Web-enabled Research (ANSWER) Program® registry.

METHODS

GH-naïve children with GH deficiency, multiple pituitary hormone deficiency, idiopathic short stature, Turner syndrome, or a history of small for gestational age were eligible (N = 1,002). Using a longitudinal statistical approach, predictive factors were identified in patients with GHD for change from baseline in height standard deviation score (ΔHSDS) following 2 years of treatment.

RESULTS

Gradual increases in ΔHSDS over time were observed for all diagnostic categories. Significant predictive factors of ΔHSDS, ranked by significance were: height velocity (HV) at 4 months > baseline age > baseline HSDS > baseline body mass index (BMI) SDS > baseline insulin-like growth factor I (IGF-I) SDS; gender was not significant. HV at 4 months and baseline BMI SDS were positively correlated, whereas baseline age, HSDS, and IGF-I SDS were negatively correlated with ΔHSDS.

CONCLUSIONS

These results may help guide GH therapy based on pretreatment characteristics and early growth response.

The cost-effectiveness of somatropin treatment for short children born small for gestational age (SGA) and children with growth hormone deficiency (GHD) in Sweden

OBJECTIVE

Reduction in health-related quality of life is common in children born small for gestational age (SGA) or children with growth hormone deficiency (GHD). Growth hormone treatment with somatropin in these children leads to normalisation of height. The aim of this study was to determine whether somatropin is a cost-effective treatment option for short children born SGA and GHD children in Sweden.

METHODS

A Markov decision-tree model was used to calculate the relative costs and health benefits associated with somatropin treatment over the lifetime of SGA and GHD children, compared with no treatment. The analysis was undertaken from a Swedish Health Service perspective. As quality-adjusted life-year (QALY) data were not obtained directly in the clinical studies, a degree of uncertainty is related to these results. Sensitivity analyses assessed the degree of uncertainty surrounding central parameters.

RESULTS

For short children born SGA, somatropin treatment was associated with an additional 3.29 QALYs at an incremental cost of 792,489 SEK (Swedish Krona), compared with no treatment. For GHD, somatropin treatment resulted in 3.25 additional QALYs at an incremental cost of 391,291 SEK. This equates to an incremental cost per QALY of 240,831 SEK and 120,494 SEK for SGA and GHD, respectively, below a cost-effectiveness threshold of 500,000-600,000 SEK/QALY.

CONCLUSIONS

Somatropin is a cost-effective treatment strategy in Sweden for children with GHD and SGA. To overcome present study limitations future clinical research should incorporate appropriate quality of life questionnaires.

Observations of nonadherence to recombinant human growth hormone therapy in clinical practice

BACKGROUND

The effectiveness of all prescribed treatments is contingent on patient adherence. The reported levels of adherence to recombinant human growth hormone (r-hGH) therapy are highly variable, but it has been suggested that nonadherence might be as high as 36% to 49%.

OBJECTIVES

This commentary discusses the factors that affect long-term adherence to injection treatment, of which r-hGH therapy is a particular challenge. It also explores potential strategies to improve adherence to injection treatments in clinical practice.

METHODS

The opinion of the authors was validated and supported by published literature. A PubMed literature search was conducted in November 2006, identifying English-language articles containing key terms growth hormone, adherence, and compliance.

RESULTS

This study found that factors associated with poor adherence to injection treatments include patients' lack of understanding of their disease, patient age, chronicity of the disease, complex treatment regimens, and insufficient information on the implications of nonadherence. Strengthening the patient-physician relationship by providing the patient with a clear understanding of his/her disease and the benefits of adherence, making improvements in injection devices, and eliminating subjective illness concepts, might increase adherence to SC injection treatments, thereby reducing increasing health care costs associated with nonadherence.

CONCLUSIONS

Poor adherence to r-hGH therapy has a dual effect, in that it leads to reduced efficacy out-comes and increased health care costs. Implementing strategies to improve adherence with injection treatment might be of particular clinical benefit to patients undergoing r-hGH therapy.

[Congenital adrenal hyperplasia and growth hormone deficiency. Special care in transition to adulthood]

Children with chronically endocrine diseases should be treated as young adults by adult endocrinologists. To optimize the transfer from the pediatric to adult endocrinologist, the model of a common transition clinic has been developed. Within this setting it should be possible to exchange experiences, extend the knowledge and understanding of the disease with the other side, and to provide for the patient an optimal outpatient care. This model, however, has only been sporadically realized to date. To set an example for the problems of the transition into adult endocrinology, we used two different endocrine diseases, the classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency, and the childhood-onset growth hormone deficiency. Specific problems for this transfer to adult care are the fixation of the patients to their pediatricians and the lack of comprehension in the need of a long term and continuous therapy. The consequence is a dramatic impairment in the quality of the therapy.

Final height in children with idiopathic growth hormone deficiency treated with a fixed dose of recombinant growth hormone

There is no consensus regarding the optimal dosing of recombinant human growth hormone (rhGH) for children with growth hormone deficiency (GHD). Our objective was to evaluate the final adult height (FAH) in children with idiopathic GHD treated with a fixed rhGH dose of 0.18 mg/kg/week. We reviewed all charts of patients with idiopathic GHD treated with rhGH since 1985 who reached FAH. Ninety-six patients were treated for an average of 5.4 years. The mean age was 11.9 years, the mean height -2.87 standard deviation score (SDS) and the mean FAH was -1.04 SDS. Females had a lower predicted adult height than males at the initiation of therapy (-2.0 vs. -1.01 SDS; p = 0.0087) but a higher FAH - predicted adult height (1.08 vs. 0.04 SDS; p = 0.0026). In multiple regression analysis, the FAH SDS was positively related to the midparental height SDS, the height SDS at GH initiation and growth velocity during the first year of therapy, and negatively correlated with peak GH and bone age at initiation (r(2) = 0.51; p < 0.005). Treatment of children with idiopathic GHD with a fixed dose of 0.18 mg/kg/week rhGH is sufficient to reach FAH within 2 SDS of the normal population range (84%) with an average FAH within -0.5 SDS of midparental height.

Relationship between Nocturnal Growth Hormone Concentrations, Serum IGF-I/IGFBP-3 Levels, Insulin Sensitivity and GH Receptor Allelic Variant in Small for Gestational Age Children

Growth hormone may help to increase final height in patients with short stature, but its efficacy is variable. It has been recently reported that the isoform of the GH receptor (GHR) that lacks exon 3 (d3-GHR) is associated with a greater growth response to GH therapy. We hypothesized that nocturnal growth hormone concentrations, basal IGF-I and IGFBP-3 levels, and insulin sensitivity might show variations among individuals depending on their GHR allelic variant. To test this hypothesis, we studied 38 prepubertal LBW children with nocturnal GH concentrations, IGF-I and IGFBP-3 levels and insulin sensitivity during OGTT and Insulin test. The GHR allelic variant was analyzed through multiplex PCR analysis in DNA from peripheral leukocytes. Characteristics of the overnight GH secretion [(mean GH: 6.8 +/- 0.6 vs. 6.2 +/- 0.5 ng/ml), (AUC: 3,227 +/- 280 vs. 2,908 +/- 212 ng/ml.min), (peak number: 4.4 +/- 0.3 vs. 4.4 +/- 0.2), (amplitude: 12 +/- 1.1 vs. 10.8 +/- 1.1 ng/ml)] did not differ between groups (f1/f1 vs. f1/d3 plus d3/d3). In addition, we did not observe any significant differences in serum IGF-I SDS (-0.49 +/- 0.26 vs. -0.40 +/- 0.35) or IGFBP-3 SDS (-1.21 +/- 0.24 vs. -0.89 +/- 0.21) nor in insulin sensitivity (WIBSI: 12 +/- 1.2 vs. 10.8 +/- 1.1) in LBW children with full length GHR compared to children carrying at least one GHRd3 allele. The distribution of the f1/f1 allelic variant and fi/d3 or d3/d3 was similar in the LBW children with or without catch-up growth. These results suggest that the GHR allelic variant does not play a significant role in the regulation of GH-IGF-I/BP3 axis or in insulin sensitivity in prepubertal LBW children.

Major determinants of height development in Turner syndrome (TS) patients treated with GH: analysis of 987 patients from KIGS

Little is known about factors determining height outcome during GH treatment in Turner syndrome (TS). We investigated 987 TS children within the Kabi International Growth Study (KIGS) who had reached near adult height (NAH) after >4 y GH treatment (including >1 y before puberty). Through multiple regression analysis we developed a model for NAH and total gain. Our results were as follows (median): 1) At start, age 9.7 yrs, height (HT) 118.0 cm (0.0 TS SDS), projected adult height 146.1 cm, GH dose 0.27 mg/kg wk; 2) NAH HT 151.0 cm (1.5 TS SDS); 3) Prepubertal gain 21.2 cm (1.6 TS SDS); 4) Pubertal gain 9.4 cm (0.0 TS SDS). NAH correlated (r = 0.67) with (ranked) HT at GH start (+), 1 year responsiveness to GH (+), MPH (+), age at puberty onset (+), age at GH start (-), and dose (+). The same factors explained (R = 0.90) the total HT gain. However, HT at GH start correlated negatively. Karyotype had no influence on outcome. Evidently, height at GH start (the taller, the better), age at GH start (the younger, the better), the responsiveness to GH (the higher, the better) and age at puberty (the later, the better) determine NAH.

Indications and recommendations for the use of recombinant human growth hormone in adult short bowel syndrome patients dependent on parenteral nutrition

Given the lack of published guidelines regarding the use of trophic factors to treat patients with short bowel syndrome (SBS), a group of experts in the field convened to discuss best-practice strategies. Trophic factors, such as recombinant human growth hormone (r-hGH) and glucagon-like peptide-2 (GLP-2), may enhance intestinal adaptation and decrease parenteral nutrition (PN) requirements; therefore, their utility in treating SBS patients was evaluated. Available clinical data on use of r-hGH therapy in SBS patients were discussed, as were the utility of r-hGH in the PN weaning process, the optimal timing of r-hGH therapy, and how to select appropriate patients for r-hGH therapy. In addition, contraindications and precautions as well as adverse effects of r-hGH treatment were discussed. The meeting culminated with the development of a treatment algorithm to summarize best-practice recommendations for the management of SBS in adult patients. This algorithm involves attempting to wean patients off PN without the use of trophic factors. If this is unsuccessful, it is recommended that patients be treated with an r-hGH regimen or participate in investigational studies using other trophic factors.

Congenital growth hormone deficiency and eye refraction: a longitudinal study

The aim of this study was to study the influence of growth hormone deficiency (GHD) on emmetropization and to evaluate the effect of growth hormone replacement therapy on eye refraction. Twenty-eight children affected by congenital GHD and undergoing substitutive therapy (group 1), and 28 healthy subjects (group 2), were prospectively studied. All patients had a thorough eye examination, including cycloplegic refraction and axial length measurement (only GHD children). After 2 years, we found in both groups a reduction of the dioptric power of the eye. A t test for paired data showed statistically significant differences in both groups (p<0.001), but the change of refraction was higher in group 2 (p<0.01). Axial length showed a statistically significant increase, according to the myopic shift (p<0.001). The change of the refraction found in GHD children could be related to the somatic growth and partially induced by growth hormone therapy. The difference between the two groups could be explained with the late beginning of the therapy in GHD children. It is possible to form the hypothesis that a correct and well-timed substitutive therapy could permit a normal emmetropization process.

Prader-Willi syndrome: clinical genetics, cytogenetics and molecular biology

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder that arises from lack of expression of paternally inherited genes known to be imprinted and located in the chromosome 15q11-q13 region. PWS is considered the most common syndromal cause of life-threatening obesity and is estimated at 1 in 10,000 to 20,000 individuals. A de novo paternally derived chromosome 15q11-q13 deletion is the cause of PWS in about 70% of cases, and maternal disomy 15 accounts for about 25% of cases. The remaining cases of PWS result either from genomic imprinting defects (microdeletions or epimutations) of the imprinting centre in the 15q11-q13 region or from chromosome 15 translocations. Here, we describe the clinical presentation of PWS, review the current understanding of causative cytogenetic and molecular genetic mechanisms, and discuss future directions for research.

Growth hormone injections improve bone quality in a mouse model of osteogenesis imperfecta

Systemic growth hormone injections increased spine and femur length in a mouse model of OI. Femur BMC, cross-sectional area, and BMD were increased. Smaller gains were produced in vertebral BMC and cross-sectional area. Biomechanical testing showed improvements to structural and material properties in the femur midshaft, supporting expanded testing of growth hormone therapy in children with OI.

INTRODUCTION

Osteoblasts in heterozygous Cola2oim mutant mice produce one-half the normal amounts of the alpha2 strand of type I procollagen. The mice experience a mild osteogenesis imperfecta (OI) phenotype, with femurs and vertebrae that require less force than normal to break in a biomechanical test.

MATERIALS AND METHODS

Subcutaneous injections of recombinant human growth hormone (rhGH) or saline were given 6 days per week to oim/+ mice between 3 and 12 weeks of age, in a protocol designed to simulate a trial on OI children.

RESULTS

rhGH injections promoted significant weight gain and skeletal growth compared with saline-treated control animals. Femur and spine lengths were increased significantly. Significant increases at the femur midshaft in cortical BMD (2.2%), BMC (15.5%), and cross-sectional area (13%) were produced by rhGH treatment. Increases in the same cortical bone parameters were measured in the metaphyseal region of the femur and in tail vertebrae, but lumbar vertebrae showed significant increases in BMC (9.6%) and cross-sectional area (10.1%) of trabecular bone. Three-point bending testing documented functional improvements to the femur mid-shafts. GH treatment produced significant increases in bone stiffness (23.7%), maximum load (30.8%), the energy absorbed by the femurs to the point of maximum load (44.5%), and the energy to actual fracture (40.4%). The ultimate stress endured by the bone material was increased by 14.1%.

CONCLUSIONS

Gains in bone length, cross-sectional area, BMD, BMC, structural biomechanical properties, and strength were achieved without directly addressing the genetic collagen defect in the mice. Results support expanded clinical testing of GH injections in children with OI.

Growth hormone (GH): usage and abuse

Growth hormone is essential for body growth but it also modulates metabolic pathways as well as neural, reproductive, immune, cardiovascular, and pulmonary functions. Numerous beneficial effects of growth hormone have led to its expanded therapeutic use in both children and adults. There are several officially approved applications of human growth hormone and many more proposed applications that resulted from huge number of clinical studies on GH therapy. Growth hormone abuse includes improper or excessive use. Over the last decade GH has become one of the most commonly abused drugs in sport due to the fact that its administration is currently undetectable. Enormous doses that are injected and frequent simultaneous abuse of other substances such as other anabolic steroids (testosterone) lead to frequent side effects that may be fatal. In spite of numerous beneficial effects of growth hormone the true physiological impact of GH replacement therapy on various metabolic parameters may be confounded by the dose and route of administration of GH so accurate physicians' monitoring during GH therapy is needed.