Growth hormone: health considerations beyond height gain

Assessment of anterior-posterior spinal curvatures in children suffering from hypopituitarism

BACKGROUND

Body posture may be disordered by vestibular dysfunction, neurological disorders, problems with the distribution of muscle tone, brain injuries, and other dysfunctions. Growth hormone deficiency (GHD) can lead to many disorders, particularly of the musculoskeletal system. During treatment with recombinant human growth hormone (rhGH), an increase in muscle mass and an improvement in bone structure can be observed in children suffering from hypopituitarism from GHD.

METHODS

The study involved 33 children suffering from hypopituitarism with GHD (9 girls and 24 boys), aged 10-14 years old. Measurements of the magnitude of their anterior-posterior spinal curvatures were made using an inclinometer. The children were examined at the medianus of the sacrum bone, the Th12-L1 intervertebral area, and the C7-Th1 intervertebral area. In order to characterize the anterior-posterior curvature of the spine, the results were compared with the general norms reported by Saunders. Statistical calculations were carried out using the statistical package Statistica 10 PL.

RESULTS

Lumbar lordosis angles were higher in the patients currently receiving growth hormone (GH) treatment than in those who had yet to receive it. There is a statistically significant positive correlation between the length of growth hormone treatment and the alpha angle. There are also statistically significant correlations between age at the beginning of growth hormone therapy and the angle of lordosis. Statistically significant correlations were also seen between age at the beginning of growth hormone therapy and the alpha angle.

CONCLUSIONS

Although there may be changes in posture at the beginning of rhGH treatment, the sooner growth hormone therapy begins, the better the body posture. The longer the growth hormone treatment, the better the posture, as expressed by the alpha angle in the sagittal plane.

Glucose Metabolism Evaluated by Glycated Hemoglobin and Insulin Sensitivity Indices in Children Treated with Recombinant Human Growth Hormone

Objective

To evaluate glucose metabolism and insulin sensitivity in children with idiopathic growth hormone (GH) deficiency, treated with recombinant human GH (rhGH), and to identify possible risk factors for the development of glucose abnormalities in this population.

Methods

We retrospectively collected data from 101 patients (60 males, median age 10.4 years, 77 prepubertal), with confirmed GH deficiency, enrolled before starting rhGH and followed up during the first three years of treatment. Glucose metabolism was evaluated annually by oral glucose tolerance test (OGTT) and glycated hemoglobin A1c (HbA1c). OGTT was used to calculate insulin sensitivity (HOMA-S) and insulin resistance (HOMA-IR), defined as HOMA-IR >3.

Results

RhGH was effective in improving growth and dosages significantly reduced after the first year of therapy. No patient developed diabetes mellitus. After one year of therapy, a significant increase in HbA1c (p=0.0042) and insulin levels (fasting p<0.0001, 60 min p=0.0018, 120 min p=0.0003) was observed, with a higher prevalence of IR (p<0.05). These indices did not alter further during the follow-up and were not related to GH dose or to family history of diabetes. A significant correlation was found only for IR indices and pubertal status, weight and age (p<0.05).

Conclusion

In this retrospective study on a large GH deficient pediatric population, conventional use of replacement therapy resulted in an increase in HbA1c and IR after one year of therapy, regardless of rhGH dosage. These alterations did not worsen significantly in the following two years and were not associated with overt diabetes.

Growth hormone therapy in children born small for gestational age: results from the ANSWER program

Growth hormone (GH) is used to treat short stature and growth failure associated with growth disorders. Birth size and GH status variably modulate response to GH therapy. The aim of this study was to determine the effect of birth size on response to GH therapy, and to determine the impact of GH status in patients born small for gestational age (SGA) on response to GH therapy. Data from the prospective, non-interventional American Norditropin® Studies: Web-Enabled Research (ANSWER) Program were analyzed for several growth outcomes in response to GH therapy over 3 years. GH-naïve children from the ANSWER Program were included in this analysis: SGA with peak GH ≥10 ng/mL (20 mIU/l), SGA with peak GH <10 ng/mL (20 mIU/l), isolated growth hormone deficiency (IGHD) born SGA, IGHD not born SGA, and idiopathic short stature. For patients with IGHD, those who did not meet criteria for SGA at birth showed greater improvements in height SDS and BMI SDS than patients with IGHD who met criteria for SGA at birth. For patients born SGA, response to GH therapy varied with GH status. Therefore, unlike previous guidelines, we recommend that GH status be established in patients born SGA to optimize GH therapy.

Is growth hormone deficiency associated with anxiety disorder and depressive symptoms in children and adolescents?: A case-control study

AIM

Children with growth hormone deficiency (GHD) are reported to experience failure in psychological maturation, and to have a lack of self-confidence in social life, and depressive symptoms. The purpose of this study was to investigate the relation between GHD and anxiety disorders and depression in children and adolescents.

METHOD

122 children and adolescents aged 7-17, 87 receiving GHD therapy and 35 before treatment, and 122 healthy volunteers were included in the study. All participants were evaluated using the Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children - Present and Lifetime Version-Turkish Version (K-SADS-PL-T). Diagnoses falling outside this semi-structured interview were made with clinical evaluation based on DSM-V diagnostic criteria. Participants were also assessed using an information form, the State-Trait Anxiety Inventory for Children (STAI-C), the Social Anxiety Scale for Children-Revised (SASC-R), and the Children's Depression Inventory (CDI), and the results were subjected to statistical analysis.

RESULTS

Generalized Anxiety Disorder (GAD) and Social Anxiety Disorder (SAD) were significantly more common in children with GHD compared to the control group (p ≤0.001 and p = 0.033, respectively). Receipt of treatment significantly reduced GAD and SAD rates in the group diagnosed with GHD (p = 0.012, and p = 0.014). Being in receipt of GH therapy also caused a significant decrease in STAIC (State) (p ≤0.001), STAIC (Trait) (p ≤0.001), SASC-R (p ≤0.001), and CDI (p ≤0.001) scale scores. Untreated subjects had more adverse scale scores than treated subjects, and treated subjects had more adverse scale scores than the control group. An increase was observed in all scale scores in the form of control group < treated group < pre-treatment group. IGF and GH-PEAK exhibited moderate negative correlation with STAIC-TRAIT, STAIC-STATE, and SASC-R, and weak negative, significant correlation with CDI (Spearman's rho p ≤0.05).

CONCLUSION

Having GHD and being in receipt of treatment resulted in lower scale scores. Children with GHD had higher GAD and SAD burdens compared to the healthy controls. The etiology of these children's existing psychiatric diseased now requires identification using more variables in psychosocial and hormonal terms.

Effects of growth hormone and functional appliance on mandibular growth in an adolescent rat model

OBJECTIVES

To investigate the individual and synergistic effects of growth hormone (GH) and functional appliance (FA) on mandibular growth in an adolescent rat model.

MATERIALS AND METHODS

Forty adolescent (6-week-old) female Wistar rats were randomly divided into four groups (10 rats in each group). The control group received a sham treatment (intra-abdominal injection of phosphate-buffered saline), the GH group received an intra-abdominal injection of recombinant human growth hormone, the FA group was treated with a mandibular advancement device, and the GH+FA group received both the GH and FA treatments. The amount of mandibular growth in each group was measured quantitatively using cone-bean computed tomography. The growth of condylar cartilage and expression of matrix metalloproteinases-1 and -13 (MMP-1 and MMP-13) and type II and X collagen (Col II and Col X) were assessed using histological staining and immunostaining techniques.

RESULTS

After 4 weeks, there was significant mandibular growth in the FA group compared with the control group ( P < .05). The GH+FA group had significantly greater mandibular length, thickness of condylar cartilage, and expression of MMP-1, MMP-13, Col II, and Col X in the cartilage than the other groups ( P < .05). The GH+FA group and GH group had significantly greater weight than the FA and control groups ( P < .05).

CONCLUSIONS

The FA as well as GH+FA stimulated mandibular growth in adolescent rats.

Possible effects of an early diagnosis and treatment in patients with growth hormone deficiency: the state of art

Growth hormone deficiency (GHD) is a relatively uncommon and heterogeneous endocrine disorder presenting in childhood with short stature. However, during the neonatal period, the metabolic effects of GHD may to require prompt replacement therapy to avoid possible life-threatening complications. An increasing amount of data suggests the importance of an early diagnosis and treatment of GHD because of its auxological, metabolic, and neurodevelopmental features with respect to the patients diagnosed and treated later in life.

The available results show favourable auxological outcomes for patients with GHD diagnosed and treated with r-hGH early in life compared with those from patients with GHD who do not receive this early diagnosis and treatment. Because delayed referral for GHD diagnosis and treatment is still frequent, these results highlight the need for more attention in the diagnosis and treatment of GHD.

Despite these very encouraging data regarding metabolic and neurodevelopmental features, further studies are needed to better characterize these findings. Overall, the importance of early diagnosis and treatment of GHD needs to be addressed.

Real-life GH dosing patterns in children with GHD, TS or born SGA: a report from the NordiNet® International Outcome Study

OBJECTIVE

To describe real-life dosing patterns in children with growth hormone deficiency (GHD), born small for gestational age (SGA) or with Turner syndrome (TS) receiving growth hormone (GH) and enrolled in the NordiNet International Outcome Study (IOS; Nbib960128) between 2006 and 2016.

DESIGN

This non-interventional, multicentre study included paediatric patients diagnosed with GHD (isolated (IGHD) or multiple pituitary hormone deficiency (MPHD)), born SGA or with TS and treated according to everyday clinical practice from the Czech Republic (IGHD/MPHD/SGA/TS: n = 425/61/316/119), France (n = 1404/188/970/206), Germany (n = 2603/351/1387/411) and the UK (n = 259/60/87/35).

METHODS

GH dosing was compared descriptively across countries and indications. Proportions of patients by GH dose group (low/medium/high) or GH dose change (decrease/increase/no change) during years 1 and 2 were also evaluated across countries and indications.

RESULTS

In the Czech Republic, GH dosing was generally within recommended levels. In France, average GH doses were higher for patients with IGHD, MPHD and SGA than in other countries. GH doses in TS tended to be at the lower end of the recommended label range, especially in Germany and the UK; the majority of patients were in the low-dose group. A significant inverse association between baseline height standard deviation score and GH dose was shown (P < 0.05); shorter patients received higher doses. Changes in GH dose, particularly increases, were more common in the second (40%) than in the first year (25%).

CONCLUSIONS

GH dosing varies considerably across countries and indications. In particular, almost half of girls with TS received GH doses below practice guidelines and label recommendations.

The Influence of Growth Hormone Treatment on Glucose Homeostasis in GrowthHormone-Deficient Children: A Six-Year Follow-Up Study

BACKGROUND

Growth hormone (GH) influences glucose homeostasis by negatively affecting insulin sensitivity, leading to a compensatory increase in insulin secretion. It has recently been reported, in animals and humans, that GH might also stimulate insulin secretion by directly affecting the growth and function of pancreatic β-cells. The aim of this work was to longitudinally study the insulin sensitivity (HOMA-S), insulin secretion [insulinogenic index (IGI)] and capacity of β-cells to adapt to changes in insulin sensitivity [oral disposition index (ODI)] in GH-deficient (GHD) children under GH treatment.

METHODS

We studied 99 GHD (62 male, 37 female; age 8.9 ± 3.5 years) children for a median period of 6 years (range 1.5-16.2). Every year, our patients underwent an oral glucose tolerance test, which was used to calculate the HOMA-S, IGI and ODI.

RESULTS

Although HOMA-S remained unchanged, an increase in IGI and ODI was observed, becoming significant after 6 years of treatment (1.25 ± 1.28 vs. 2.35 ± 2.38, p < 0.05 and 0.57 ± 0.68 vs. 1.50 ± 1.92, p < 0.01, respectively).

CONCLUSION

Our results suggest a positive influence of GH treatment on the β-cell secretory capacity in children with GH deficiency. © 2016 S. Karger AG, Basel.

Attaining genetic height potential: Analysis of height outcomes from the ANSWER Program in children treated with growth hormone over 5 years

OBJECTIVE

This study aimed to assess attainment of genetic height potential after long-term growth hormone (GH) treatment in GH-naïve children diagnosed with isolated growth hormone deficiency (IGHD), multiple pituitary hormone deficiency (MPHD), born small for gestational age (SGA), or idiopathic short stature (ISS) enrolled in the American Norditropin®

STUDIES

Web-enabled Research (ANSWER) Program.

DESIGN

Children with IGHD (n=2884), MPHD (n=200), SGA (n=481), or ISS (n=733) with baseline height standard deviation score (HSDS)≤-2 were assessed over 5 years of GH treatment for mean HSDS, change in HSDS (ΔHSDS), and corrected HSDS (HSDS-target HSDS).

RESULTS

Mean HSDS and corrected HSDS significantly increased to close to target height across all diagnostic groups after 5 years of GH treatment (P<0.0001). ∆HSDS at year 5 increased for all groups (IGHD: 1.8; MPHD: 2.1; SGA: 1.8; ISS: 1.6). Among patients who continued GH for 5 years, mean insulin-like growth factor-I (IGF-I) SDS increased to within normal range across all groups. Body mass index (BMI) SDS remained relatively stable in all diagnostic groups. Bone age (BA) increased, and the mean BA to chronological age (BA/CA) ratio reached or approached 1 across diagnostic groups over 5 years of GH treatment.

CONCLUSIONS

Long-term GH therapy resulted in a significant increase in mean HSDS and corrected HSDS from baseline values in all diagnostic groups. The observed increase in mean corrected HSDS is consistent with growth that approached the patients' genetic height potential, although complete height gains will be evaluated at the attainment of final height.

Increased height standard deviation scores in response to growth hormone therapy to near-adult height in older children with delayed skeletal maturation: results from the ANSWER Program

Background

A primary goal of recombinant human growth hormone therapy (GHT) in children is attaining normal adult height. In this study, children with growth hormone deficiency (GHD) (including isolated idiopathic growth hormone deficiency [IGHD] and multiple pituitary hormone deficiency [MPHD]), idiopathic short stature (ISS), and Turner syndrome (TS) were evaluated for near-adult height (NAH) and percent achieving NAH within the normal range after approximately 4 years of GHT.

Methods

Data from the American Norditropin® Studies: Web-Enabled Research (ANSWER) Program were analyzed for NAH from age at treatment start (ATS) (i.e., referral age as defined by age at enrollment in the study) to last clinic visit using one of the following two criteria: 1) age ≥18 years, or 2) if male: ≥16 years and height velocity (HV) <2 cm/year; if female: ≥15 years and HV <2 cm/year. All patients had a baseline height standard deviation score (HSDS) ≤ -2, and either GHD (n = 201), ISS (n = 19), or TS (n = 41). The main outcome measures included HSDS and corrected HSDS (HSDS-target HSDS) in response to GH treatment, and correlation of ATS with NAH HSDS.

Results

Mean (± SD) chronological and bone ages at baseline were 14.0 ± 2.1 years and 11.7 ± 2.0 years, respectively, and mean GHT duration was 4.0 ± 1.6 years. Mean HSDS (baseline to NAH; GHD: -2.7 to -1.0; ISS: -2.8 to -1.4; TS: -3.0 to -1.8) and mean corrected HSDS (baseline to NAH; GHD: -2.1 to -0.3; ISS: -2.1 to -0.6; TS: -1.8 to -0.6) increased across diagnostic indications. Percentages of patients reaching near-adult HSDS > -2 were GHD: 87.6%; ISS: 78.9%; TS: 65.8%. Significant negative correlations were found between ATS and NAH HSDS when analyzed by sex.

Conclusions

Despite a relatively advanced childhood age, the majority of GH-treated patients attained mean near-adult HSDS within the normal range (HSDS > -2). Negative correlations of ATS with near-adult HSDS indicate that an earlier age at treatment start would likely have resulted in greater adult height achieved in both male and female patients.

The effect of recombinant human growth hormone therapy on left-ventricular chamber size and function in children with growth hormone deficiency

This study was designed to assess the effect of recombinant human growth hormone (rhGH) therapy on left-ventricular (LV) chamber size and function in children with idiopathic isolated growth hormone deficiency (GHD) using conventional echocardiography and tissue Doppler imaging (TDI). Thirty patients (19 boys and 11 girls) with idiopathic isolated GHD were followed-up for 12 months. Mean age of patients was 11.0 ± 2.6 years (range 6.3-15.5). At baseline and at 3, 6, and 12 months of treatment, the structure of the left ventricle was assessed by conventional echocardiography and myocardial rates and time intervals by TDI. There was a significant increase in LV mass (LVM) compared with pretreatment values. Like LVM, relative wall thickness (RWT) was also increased significantly. The significant increase in LVM indexed to body surface area and RWT became apparent at month 3 of treatment with a significant increase in LVM indexed to height(2.7) at treatment month 6. Normalized LVM increased as early month 3 of treatment, and a steady increase was observed until month 12. However, no patient had LVM > +2 standard deviation scores at month 12 of treatment. No significant differences were observed in functional parameters of the left ventricle and the interventricular septum. The results of this study showed that rhGH therapy causes an increase in myocardial mass without changing the geometry or function of the myocardium. Therefore, the increase in myocardial mass appears to be concentric, thus causing remodeling instead of hypertrophy.

Isolated growth hormone deficiency (GHD) in childhood and adolescence: recent advances

The diagnosis of GH deficiency (GHD) in childhood is a multistep process involving clinical history, examination with detailed auxology, biochemical testing, and pituitary imaging, with an increasing contribution from genetics in patients with congenital GHD. Our increasing understanding of the factors involved in the development of somatotropes and the dynamic function of the somatotrope network may explain, at least in part, the development and progression of childhood GHD in different age groups. With respect to the genetic etiology of isolated GHD (IGHD), mutations in known genes such as those encoding GH (GH1), GHRH receptor (GHRHR), or transcription factors involved in pituitary development, are identified in a relatively small percentage of patients suggesting the involvement of other, yet unidentified, factors. Genome-wide association studies point toward an increasing number of genes involved in the control of growth, but their role in the etiology of IGHD remains unknown. Despite the many years of research in the area of GHD, there are still controversies on the etiology, diagnosis, and management of IGHD in children. Recent data suggest that childhood IGHD may have a wider impact on the health and neurodevelopment of children, but it is yet unknown to what extent treatment with recombinant human GH can reverse this effect. Finally, the safety of recombinant human GH is currently the subject of much debate and research, and it is clear that long-term controlled studies are needed to clarify the consequences of childhood IGHD and the long-term safety of its treatment.

Etiologies and early diagnosis of short stature and growth failure in children and adolescents

Accurate measurement of height and weight using standardized techniques is a fundamental component of pediatric medical visits. Calculation of height velocity over time enables comparison with standardized growth charts to identify potential deviations from normal. Growth deviations may be expressed as SD from the normal population mean for children of comparable age and sex; children with heights >2 SD below the mean are generally classified as short stature. In a child with suspected impaired growth, a detailed evaluation should be conducted to identify the cause. Such an evaluation may include a combination of personal, family, and social history; physical examination; general and perhaps specialized laboratory evaluations; radiologic examinations; genetic testing; and consultation with a pediatric subspecialist, such as a pediatric endocrinologist. Variants of normal growth include familial short stature, constitutional delay of growth and puberty, and small for gestational age with catch-up growth. Pathological causes of abnormal growth include many systemic diseases and their treatments, growth hormone deficiency, and a series of genetic syndromes, including Noonan syndrome and Turner syndrome. Children with short stature in whom no specific cause is identified may be diagnosed with idiopathic short stature. Early identification of abnormal growth patterns and prompt referral to specialist care offer children with growth failure and/or short stature the greatest chance for appropriate diagnosis, treatment, and improved clinical outcomes.

Growth hormone treatment adherence in prepubertal and pubertal children with different growth disorders

BACKGROUND/AIMS

Treatment of children with growth disorders with recombinant human growth hormone is necessary for improved outcomes, including final height.

METHODS

Adherence data from the Observational Study Saizen®-online, recorded with the easypod™ device collected between October 2009 and May 2011, were analyzed in pediatric patients receiving recombinant human growth hormone treatment for a variety of growth disorders.

RESULTS

Data from 75 children (46 boys, 29 girls) with different growth disorders were analyzed over a period of 343 ± 201 (SD) days. Boys and girls showed similar mean ± SD adherence rates of 90.5 ± 3.1% and 92.2 ± 10.7%, respectively. Pubertal children (n = 41) had a significantly lower adherence rate (89.1 ± 13.7%) than prepubertal children (n = 29) (96.5 ± 3.9%; p < 0.005). There were nonsignificant differences in adherence rates according to diagnosis: growth hormone deficiency (n = 48) 91.4 ± 11.0%, small for gestational age (n = 18) 91.1 ± 15.3%, Turner syndrome (n = 6) 86.0 ± 14.5%, and chronic renal failure (n = 3) 99.3 ± 1.0%, although the latter two groups were small.

CONCLUSION

Our data indicate that only a small number of pediatric patients using the easypod device had poor adherence to treatment. Further reliable adherence data are required to identify factors affecting long-term adherence in this population.

The association between growth response to growth hormone and baseline body composition of children with growth hormone deficiency

OBJECTIVE

We wanted to examine the relationship between initial growth response to recombinant human Growth Hormone (rhGH) treatment and body composition in children with growth hormone deficiency (GHD).

DESIGN AND METHODS

Forty-two patients (21 boys and 21 girls) aged between 5.7-15.5 years (mean age: 10.8 ± 2.6 years) with isolated GHD. The auxological and laboratory data (GH and IGF-I levels) and results of bioelectrical impedance analyses were evaluated. Children with GHD were followed up for 12 months and categorized according to growth response to rhGH into good and poor responders (change in height of > 0.7 SDS or < 0.7 SDS over one year respectively). Mean doses of rhGH per kg of fat free mass (FFM) were calculated.

RESULTS

Forty-eight percent of patients showed a good growth response to rhGH therapy. At study entry, mean age, height SDS, weight SDS, serum IGF-1 SDS, IGFBP-3 SDS, growth velocity prior to rhGH therapy, GH after clonidine and l-dopa were similar in the two groups. At baseline, BMI SDS and waist-hip ratio were significantly higher in good responders (p = 0.02 and p = 0.006, respectively). Good responders had lower percentages of FFM (73.4 ± 8.9 vs. 83.1 ± 5.9) and total body water (TBW) (56.5 ± 5.3 vs. 63.1 ± 4.4), compared to poor responders (p < 0.05). There were significant correlations between changes in height SDS over one year and baseline body composition in children with GHD on rhGH treatment (r = -0.617 for percentage of FFM, r = -0.629 for percentage of TBW, p < 0.001). A correlation between BMI SDS, waist-hip ratio, mean rhGH dose per FFM and growth response was observed only in prepubertal subjects.

CONCLUSION

Baseline body composition data in children with GHD can be used to predict the growth response to rhGH treatment. A management strategy that involves titrating rhGH dose according to FFM as a means of optimizing the growth response to intervention requires further study.

Product wastage from modern human growth hormone administration devices: a laboratory and computer simulation analysis

BACKGROUND

Treatment of growth hormone disorders typically involves daily injections of human growth hormone (GH) over many years, incurring substantial costs. We assessed the extent of undesired GH loss due to leakage in the course of pen preparation prior to injection, and differences between the prescribed dose, based on patient weight, and the actual delivered dose based on pen dosing increments in five GH administration devices.

METHODS

Norditropin® prefilled FlexPro®, NordiFlex®, NordiLet®, and durable NordiPen®/SimpleXx® 5 mg pens (Novo Nordisk A/S, Bagsværd, Denmark) and durable Omnitrope® Pen-5 devices (Sandoz, Holzkirchen, Germany) were tested (n = 40 for each device type). Product wastage was measured in accordance with validated protocols in an ISO (International Organization for Standardization) 11608-1 and Good Manufacturing Practice compliant laboratory. The average mass of wasted GH from each device type was measured in simulations of dripping with the needle attached prior to injection and while setting a dose. Statistical significance (P < 0.05) was confirmed by Student's t-test, and a model was constructed to estimate mean annual GH wastage per patient in cohorts of pediatric patients with GH disorders.

RESULTS

Mean GH mass wasted with the needle on prior to injection was 0.0 μg with Norditropin pens, relative to 98 μg with Omnitrope Pen-5. During dose dialing, 0.0-2.3 μg of GH was lost with Norditropin pens versus 0.8 μg with Omnitrope Pen-5. All Norditropin and Omnitrope device comparisons were statistically significant. Modeling GH wastage in a US cohort showed 5.5 mg of annual GH wastage per patient with FlexPro versus 43.6 mg with Omnitrope, corresponding to 7-8 additional pens per patient annually.

CONCLUSION

Overall, Norditropin pens resulted in significantly less wastage than the Omnitrope Pen-5. The study suggests that GH devices of the same nominal volume exhibit differences that may affect the frequency of GH prescription refills required to remain adherent to therapy.

Treatment of children and adolescents with idiopathic short stature

Idiopathic short stature (ISS) is defined as shortness in childhood without a specific cause. ISS may be familial or nonfamilial and may be associated with or without delay of pubertal development. Treatment can be considered in an attempt to reduce the psychological burden caused by short stature in childhood and adult life. If counselling alone is not sufficient, medical modifications of the growth process can be attempted. In cases with pubertal delay, sex steroids, such as testosterone and oxandrolone, can favourably influence height velocity and growth tempo, although adult height is not affected. Medications that prolong the process of growth--for example, gonadotropin-releasing hormone agonists or aromatase inhibitors--might increase adult height, but findings to date are still experimental. Growth hormone therapy is approved for the treatment of very short children with reduced adult height expectation, as evidence has accumulated that this therapy can increase height in childhood and in adult life. Sensitivity to growth hormone is impaired in patients with ISS; therefore, doses higher than a replacement dose have to be applied. This treatment still needs to be optimized in terms of efficacy, cost-effectiveness and long-term safety. A debate is ongoing concerning the psychological benefit of height increase, with clinicians warning against the medicalization of a deviation in height.

Blunted response to a growth hormone stimulation test is associated with unfavorable cardiovascular risk factor profile in childhood cancer survivors

BACKGROUND

Childhood cancer survivors (CCS) are at risk for growth hormone (GH) deficiency. CCS are also at increased risk for early mortality from cardiovascular (CV) disease, but the association between GH levels and CV risk remains poorly understood. The goal of this study was to examine the cross-sectional association between stimulated GH levels and CV risk factors in CCS younger than 18 years.

PROCEDURE

A total of 276 CCS (147 males, 14.4 ± 2.6 years) ≥5 years after cancer diagnosis, and 208 sibling controls (112 males, 13.6 ± 2.4 years) participated in this cross-sectional study, which included anthropometry, body composition, and metabolic studies. Blunted response (BR) was defined as peak GH level <7 µg/L after clonidine and arginine. Insulin sensitivity (M(lbm) ) was measured by euglycemic hyperinsulinemic clamp. Statistical analyses used linear and logistic regression accounting for sibling clustering, adjusted for age, sex, Tanner stage, and adiposity.

RESULTS

Thirty-four (12%) CCS showed BR to GH stimulation. BR CCS were shorter and had a lower IGF-1 than controls; only 6 of 34 received cranial radiation therapy. CCS with normal stimulated GH response were similar to controls for CV risk factors. Conversely, BR CCS had greater adiposity, higher lipids, and lower M(lbm) than controls. Differences in lipids and M(lbm) between BR CCS and controls remained significant after adjustment for BMI or visceral fat.

CONCLUSIONS

BR to GH stimulation is prevalent in CCS youth and is associated with an unfavorable CV risk factor profile. Further studies are needed to establish the mechanisms of these associations.

Urine metabonomic profiling of a female adolescent with PIT-1 mutation before and during growth hormone therapy: insights into the metabolic effects of growth hormone

OBJECTIVE

Growth hormone (GH) is a protein hormone with important roles in growth and metabolism. The objective of this study was to investigate the metabolism of a human subject with severe GH deficiency (GHD) due to a PIT-1 gene mutation and the metabolic effects of GH therapy using Nuclear Magnetic Resonance (NMR)-based metabonomics. NMR-based metabonomics is a platform that allows the metabolic profile of biological fluids such as urine to be recorded, and any alterations in the profile modulated by GH can potentially be detected.

DESIGN

Urine samples were collected from a female subject with severe GHD before, during and after GH therapy, and from healthy age- and sex-matched controls and analysed with NMR-based metabonomics.

SETTING

The samples were collected at a hospital and the study was performed at a research facility.

PARTICIPANTS

We studied a 17 year old female adolescent with severe GHD secondary to PIT-1 gene mutation who had reached final adult height and who had ceased GH therapy for over 3 years. The subject was subsequently followed for 5 years with and without GH therapy. Twelve healthy age-matched female subjects acted as control subjects.

INTERVENTION

The GH-deficient subject re-commenced GH therapy at a dose of 1 mg/day to normalise serum IGF-1 levels.

MAIN OUTCOME MEASURES

Urine metabolic profiles were recorded using NMR spectroscopy and analysed with multivariate statistics to distinguish the profiles at different time points and identify significant metabolites affected by GH therapy.

RESULTS

NMR-based metabonomics revealed that the metabolic profile of the GH-deficient subject altered with GH therapy and that her profile was different from healthy controls before, and during withdrawal of GH therapy.

CONCLUSION

This study illustrates the potential use of NMR-based metabonomics for monitoring the effects of GH therapy on metabolism by profiling the urine of GH-deficient subjects. Further controlled studies in larger numbers of GH-deficient subjects are required to determine the clinical benefits of NMR-based metabonomics in subjects receiving GH therapy.

Synergistic effect of obesity and lipid ingestion in suppressing the growth hormone response to exercise in children

Diet plays an important role in modulating exercise responses, including activation of the growth hormone (GH)/insulin-like growth factor-I (IGF-1) axis. Obesity and fat ingestion were separately shown to reduce exercise GH responses, but their combined effect, especially important in children, has not been studied. We therefore measured the GH response to exercise [30-min intermittent cycling, ten 2-min bouts at ~80% maximal aerobic capacity (Vo(2max)), separated by 1-min rest], started 45 min after ingestion of a high-fat meal (HFM) in 16 healthy [controls; body mass index percentile (BMI%ile) 51 ± 7], and 19 obese (Ob, BMI%ile 97 ± 0.4) children. Samples were drawn at baseline (premeal), and at start, peak, and 30 min postexercise. In the Ob group, a marked ~75% suppression of the GH response (ng/ml) to exercise was observed (2.4 ± 0.6 vs. 10.6 ± 2.1, P < 0.001). This level of suppression was also significantly greater compared with age-, fitness-, and BMI-matched historical controls that had performed identical exercise in fasting conditions. Our data indicate that the reduction in the GH response to exercise, already present in obese children vs. healthy controls, is considerably amplified by ingestion of fat nutrients shortly before exercise, implying a potentially downstream negative impact on growth factor homeostasis and long-term modulation of physiological growth.

Microarchitecture, but not bone mechanical properties, is rescued with growth hormone treatment in a mouse model of growth hormone deficiency

Growth hormone (GH) deficiency is related to an increased fracture risk although it is not clear if this is due to compromised bone quality or a small bone size. We investigated the relationship between bone macrostructure, microarchitecture and mechanical properties in a GH-deficient (GHD) mouse model undergoing GH treatment commencing at an early (prepubertal) or late (postpubertal) time point. Microcomputed tomography images of the femur and L4 vertebra were obtained to quantify macrostructure and vertebral trabecular microarchitecture, and mechanical properties were determined using finite element analyses. In the GHD animals, bone macrostructure was 25 to 43% smaller as compared to the GH-sufficient (GHS) controls (P < 0.001). GHD animals had 20% and 19% reductions in bone volume ratio (BV/TV) and trabecular thickness (Tb.Th), respectively. Whole bone mechanical properties of the GHD mice were lower at the femur and vertebra (67% and 45% resp.) than the GHS controls (P < 0.001). Both early and late GH treatment partially recovered the bone macrostructure (15 to 32 % smaller than GHS controls) and the whole bone mechanical properties (24 to 43% larger than GHD animals) although there remained a sustained 27-52% net deficit compared to normal mice (P < 0.05). Importantly, early treatment with GH led to a recovery of BV/TV and Tb.Th with a concomitant improvement of trabecular mechanical properties. Therefore, the results suggest that GH treatment should start early, and that measurements of microarchitecture should be considered in the management of GHD.

The role of growth hormone and insulin-like growth factor-1 in Crohn's disease: implications for therapeutic use of human growth hormone in pediatric patients

PURPOSE OF REVIEW

This review evaluates the role of the growth hormone (GH) and insulin-like growth factor (IGF) in influencing linear growth in pediatric Crohn's disease. It also examines the current evidence concerning the use of recombinant human growth hormone (rhGH) as a potential therapy in achieving optimal growth and inducing mucosal healing for pediatric Crohn's disease.

RECENT FINDINGS

Current treatment strategies for Crohn's disease including antitumor necrosis factor-α (TNF-α) therapy have been demonstrated to improve growth velocity, but linear growth deficits persist despite optimization of therapy. By complex mechanisms, including the reduction of levels of IGF-1 and induction of systemic and hepatic GH resistance, cytokines such as TNF-α and interleukin-6 (IL-6), commonly elevated in active Crohn's disease, are important as mediators of linear growth delay. Recent evidence suggests that rhGH therapy is effective in improving short-term linear growth for a selected group of patients but of limited benefit as a therapy for improving mucosal disease and reducing clinical disease activity.

SUMMARY

Crohn's disease interacts with the GH-IGF-1 axis in important ways. Recent studies evaluating rhGH use in pediatric Crohn's disease have demonstrated some efficacy in reversing persistent linear growth delay but limited benefits in terms of improving mucosal disease and clinical disease activity. Larger studies of adequate power are needed to confirm a true benefit in terms of growth, to examine a potential benefit with regard to modification of disease activity, and to evaluate long-term risks.

Efficacy and harms of nasal calcitonin in improving bone density in young patients with inflammatory bowel disease: a randomized, placebo-controlled, double-blind trial

OBJECTIVES

There are very few published studies of agents having the potential to improve bone health in children with inflammatory bowel disease (IBD). The objective of this study was to establish the efficacy and safety of intranasal calcitonin in improving bone mineral density (BMD) in young patients with IBD and to define additional factors that impact bone mineral accrual.

METHODS

We conducted a randomized, placebo-controlled, double-blind clinical trial in 63 participants, ages 8-21 years, with a spinal BMD Z-score ≤ -1.0 s.d. measured by dual energy X-ray absorptiometry. Subjects were randomized to 200 IU intranasal calcitonin (n=31) or placebo (n=32) daily. All received age-appropriate calcium and vitamin D supplementation. Subsequent BMD measurements were obtained at 9 and 18 months.

RESULTS

Intranasal calcitonin was well tolerated. Adverse event frequency was similar in both treatment groups, and such events were primarily minor, reversible, and limited to the upper respiratory tract. The BMD Z-score change documented at screening and 9 months and screening and 18 months did not differ between the two therapeutic arms. In participants with Crohn's disease, the spinal BMD Z-score improved between screening and 9 months (change in spine BMD Z-score (ΔZSBMD)(9-0)) in the calcitonin group (ΔZSBMD(9-0)(calcitonin)=0.21 (0.37), ΔZSBMD(9-0)(placebo)=-0.15 (0.5), P=0.02); however, this was only a secondary subgroup analysis. Bone mineral accrual rate during the trial did not lead to normalization of BMD Z-score in this cohort. Factors favoring higher bone mineral accrual rate were lower baseline BMD and higher baseline body mass index Z-score, improvement in height Z-score, higher serum albumin, hematocrit and iron concentration, and more hours of weekly weight-bearing activity. Factors associated with lower bone mineral accrual rate were more severe disease-as indicated by elevated inflammatory markers, need for surgery, hospitalization, and the use of immunomodulators-and higher daily caffeine intake.

CONCLUSIONS

Intranasal calcitonin is well tolerated but does not offer a long-term advantage in youth with IBD and decreased BMD. Bone mineral accrual rate remains compromised in youth with IBD and low BMD raising concerns for long-term bone health outcomes. Improvement in nutritional status, catch-up linear growth, control of inflammation, increase in weight-bearing activity, and lower daily caffeine intake may be helpful in restoring bone density in children with IBD and low BMD.

Therapy of growth disorders

PURPOSE OF REVIEW

We review recent developments in the therapy of growth disorders, focusing mainly on recent developments in the field of growth hormone (GH) therapy.

RECENT FINDINGS

Review of current practice reveals wide variation in the approach to short stature and the institution of GH therapy. No new indications for GH treatment have been approved by the Food and Drug Administration since 2007, but off-label use has been explored in several chronic illnesses. There is also increasing focus on GH effects beyond increase in stature (e.g. effects on body composition and bone density). As the experience with GH increases, the long-term risks and outcomes are better understood and risks appear to be low. Data regarding beneficial effects of GH in Prader-Willi syndrome are accumulating but questions remain about patient selection, start age and safety. Recombinant insulin-like growth factor 1 has become more widely available and has been aggressively promoted for Food and Drug Administration-approved indications as well as off-label uses in the last few years. The use of aromatase inhibitors has been tempered by concern about side-effects and lack of efficacy.

SUMMARY

Growth hormone remains the mainstay of therapy for growth disorders, though other options, including recombinant insulin-like growth factor 1, are being investigated in various settings.

Uniparental disomies 7 and 14

Normally, one inherits one chromosome of each pair from one parent and the second chromosome from the other parent. Uniparental disomy (UPD) describes the inheritance of both homologues of a chromosome pair from the same parent. The biological basis of UPD syndromes is disturbed genomic imprinting. The consequences of UPD depend on the specific chromosome/segment involved and its parental origin. Phenotypes range from unapparent to unmasking of an autosomal-recessive disease to presentation as a syndromic imprinting disorder. Whilst paternal UPD(7) is clinically unapparent, maternal UPD(7) is one of several causes of Silver-Russell syndrome. Presentation of paternal UPD(14) ("Kagami syndrome") is a thoracic dysplasia syndrome with mental retardation and limited survival. Findings in maternal UPD(14) ("Temple") syndrome show an age-dependent overlap with the well-known maternal UPD(15) (Prader-Willi) syndrome and are dominated by initial failure to thrive followed by obesity, learning difficulties and precocious puberty. Diagnostic strategies to tackle the genetic heterogeneity of UPD(7) and UPD(14) syndromes will be explained. Management issues in UPD(7) and UPD(14) patients will be discussed, and finally areas requiring further research will be outlined.

Human growth hormone treatment: synthesis of literature on product delivery systems and administration practices

PURPOSE

To synthesize current literature on recombinant human growth hormone (rhGH) use and to identify areas of research that have received little to no attention in light of administration practice and patient perception/behavior.

DESIGN AND METHODS

Relevant articles for a systematic review were identified through PubMed.

RESULTS

A total of 43 articles were identified: 9 (15.9%) studies on product administration practices and 34 (84.1%) on patient behavior patterns. Patients primarily preferred simple, convenient, and easy-to-use delivery devices. However, literature addressing the effect of convenient product administration practices on treatment outcomes using real-world patient/caregiver data is lacking.

PRACTICE IMPLICATIONS

Better understanding of real-world product administration practices will help nurses identify areas of improvement in patient education and training.