Sustained benefits of growth hormone on body composition, fat utilization, physical strength and agility, and growth in Prader-Willi syndrome are dose-dependent

BACKGROUND: Obesity and hypotonia in children with Prader-Willi syndrome (PWS) are accompanied by abnormal body composition resembling a growth hormone (GH) deficient state. Hypothalamic dysfunction in PWS includes decreased GH secretion, suggesting a possible therapeutic role for GH treatment. While recent studies have demonstrated short-term benefits of treatment with GH, a critical question is whether beneficial changes persist or wane with prolonged therapy, and whether these effects on body composition are dose-dependent as seen in adult GH deficiency. OBJECTIVES AND METHODS: After 24 months of GH theapy at a dose of 1 mg/m2/day ("standard dose"), the effects of 12 additional months of GH treatment at varying doses (0.3-1.5 mg/m2/day) on growth, body composition, strength and agility, pulmonary function, resting energy expenditure (REE), and fat utilization were assessed in 46 children with PWS. Percent body fat, lean muscle mass, and bone mineral density (BMD) were measured by dual X-ray absorptiometry (DXA). Indirect calorimetry was used to determine REE and to calculate respiratory quotient (RQ). RESULTS: During months 24-36 of GH therapy, further changes in body composition (decrease in fat mass, and increase in lean body mass), growth velocity, and REE occurred with standard and higher-dose GH therapy (1.5 mg/m2/day), but not with lower dose GH (0.3 mg/m2/day). Prior improvements in BMD, and strength and agility, which occurred during the initial 24 months, were sustained during the additional 12 months (to 36 months) regardless of dose. CONCLUSIONS: Salutary and sustained GH-induced changes in growth, body composition, and physical function in children with PWS require GH doses of >0.3 mg/m2/day. Conversely, BMD increased during the additional 12 months of therapy regardless of GH dose. Lower doses of GH, effective in improving body composition in adults with GHD, do not appear to be effective in children with PWS.     

Transition of childhood-onset growth hormone-deficient patients to adult healthcare

In patients with childhood-onset growth hormone (GH) deficiency who have reached adult height, the transition from pediatric to adult healthcare is an appropriate time for reassessment of GH status. For patients in whom persistent GH deficiency (GHD) is established by appropriate testing, reinstitution of GH therapy or its continuation can improve quality of life, optimize body composition and bone mineral density, as well as reduce cardiovascular risks associated with GHD. Ongoing GH therapy should be individualized with attention paid to changes in serum insulin-like growth factor (IGF)-I concentrations, body composition, and occurrence of adverse effects such as edema and arthralgia. GH deficient patients who discontinue childhood GH replacement therapy and are not restarted as adults should undergo long-term surveillance to detect possible adverse consequences (e.g. reduced bone mineral density) typically associated with interruption of GH treatment.     

Mechanisms of reduced body growth in the pubertal feminized male rat: unbalanced estrogen and androgen action on the somatotropic axis

It is well known that the sex difference in body growth at puberty is modulated by a complex interplay between sex steroids and somatotropic axis; however, the exact role played by sex steroids remains a matter of controversy. The aim of this study was to assess the mechanisms by which sex steroids regulate body growth during pubertal development. Flutamide, a non-steroid-blocking androgen receptor, was subcutaneously administered to 30-d-old male Wistar rats for 4 wk. The blockade of the androgen receptor led to a marked elevation in serum testosterone and an increment in serum estradiol. Flutamide administration decreased body weight gain, serum IGF-I levels, hepatic IGF-I mRNA, and GH receptor mRNA content. There were no significant changes in serum GH concentration, pituitary GH reserve, and pituitary GH mRNA content. Flutamide lowered hypothalamic somatostatin mRNA content and augmented hypothalamic immunoreactive somatostatin stores, but did not alter hypothalamic immunoreactive GH-releasing factor stores. Our findings indicate that during pubertal development of the male rat, the imbalance between androgen and estrogen actions determines an abnormal somatic growth, which is at least partly exerted through the peripheral or hepatic modification of the somatotropic axis that occurs under the high or exclusive action of estrogens. Potential implication of coincident sex-specific regulated mode of pulsatile GH secretion cannot be excluded from this random serum GH sample study.     

Five years of growth hormone treatment in children with Prader-Willi syndrome. Swedish National Growth Hormone Advisory Group

The authors have followed 18 prepubertal children (3-12 years of age) with Prader-Willi syndrome during 5 years of growth hormone (GH) treatment. Initially, all the children participated in a randomized, controlled GH trial, conducted to assess the effects of GH treatment on growth, body composition and behaviour. GH was administered to group A (n = 9) at a dose of 0.1 IU/kg/day (0.033 mg/kg/day) for 2 years. Group B (n = 9) was untreated for the first year, but the children were given GH at a dose of 0.2 IU/kg/day (0.066 mg/kg/day) during the second year. Thereafter, all children stopped GH treatment for 6 months and were then restarted with GH at a dose of 0.1 IU/kg/day (0.033 mg/kg/day). During the first year of GH treatment, there was a dramatic increase in height SDS in both groups. The attained height percentile was maintained during the continued GH treatment. Five years after the start of GH treatment, mean height SDS is still above average for age. Four children have reached final height, all within 2 SD of target height. During the first year of GH treatment, body mass index (BMI) SDS decreased significantly from 3.0 to 1.5 SDS in group A and from 2.8 to 1.2 SDS in group B, but it increased again during the 6-month period without treatment. Following the restart of GH treatment, BMI SDS has stabilized at 1.7 SDS for group A and 2.5 SDS for group B. In 16 of 18 patients, fasting insulin, glucose and the A1c fraction of glycosylated haemoglobin remained within normal ranges during 5 years of GH treatment. Following a period of rapid weight gain, two children have developed non-insulin-dependent diabetes mellitus. Glucose homeostasis returned to normal when GH treatment was withdrawn. In conclusion, GH treatment has a proven favourable effect on growth and body composition in patients with Prader-Willi syndrome. Treatment should be individualized, and close surveillance of glucose homeostasis is needed, especially if the patient is severely obese.     

Growth and Development of Children with Chronic Renal Failure

ABSTRACT. Preliminary results from an ongoing multicentre study on pubertal growth and sexual maturation in chronic renal failure are presented. Puberty was delayed by approximately 2.5 years in both sexes in children with chronic renal failure. There was also an irreversible decline in height SDS during puberty. The pulsatile secretion of growth hormone (GH) and luteinizing hormone (LH) were disrupted in patients on conservative treatment or dialysis compared with those in patients with renal transplants; the mean nocturnal GH level and the mean GH peak amplitude were increased, while the number of pulses and peak amplitude of LH were decreased. The biopotency of LH, expressed as the ratio of bioactive to immunoreactive LH, was suppressed in patients with renal transplants.     

Gender and hormonal regulation of growth

Puberty is the transitional period between childhood and adulthood when substantial growth, sexual maturation, and reproductive capacity is attained. The onset of puberty is triggered by the combined action of the somatotropic (GH-IGF-I) and gonadotropic (GnRH-LH/FSH-sex steroid) hormone axes, the latter of which stimulates the former to produce the pubertal growth spurt. Studies of GH secretion in boys and girls, in Turner's syndrome, in hypogonadal girls, and in androgen-deficient boys have revealed estrogen-dependent mechanisms controlling GH production, age-dependent response to and control of GH, and gender-dependent differences in response to GH therapy. The interplay between the somatotropic and gonadotropic hormone axes during puberty has profound implications on the treatment of adolescent patients in need of hormone replacement therapy for growth deficiency or hypogonadism.     

Growth retardation in chronic diseases: possible mechanisms

Multiple and complex mechanisms are likely to be involved in producing the growth retardation that occurs in children with chronic disease. The principal mechanisms in the pathway leading to growth arrest include too little substrate available to the child, excessive need for and over-consumption of substrate, and inefficient management of body components needed for growth. It is proposed that alterations in the growth hormone (GH)-insulin-like growth factor (IGF) system play a major role at each of the steps between insult from chronic disease and growth retardation. When substrate is insufficient, the production and action of IGF-I are attenuated at multiple points in the GH-IGF cascade. When over-consumption of substrate occurs, a situation of 'internal starvation' probably develops--leading to events similar to those that take place when substrate supply is inadequate. Finally, conditions that cause inefficient management of body components needed for growth, as characterized by increased proteolysis, appear to be attenuated by GH and IGF-I.     

Five-years growth hormone (GH) treatment in adults with Prader-Willi syndrome

AIM: We have previously shown that 1 year of growth hormone (GH) treatment to adults with Prader-Willi syndrome (PWS) has beneficial effects on body composition. The aim of the present observational study was to re-evaluate our cohort, with focus on long-term GH treatment. METHODS: Seven men and seven women, median age 31 years, were available for follow-up for 6 years. Nine were on GH treatment for 5 years. Body composition was measured with Dual Energy X-ray absorptiometry (DXA). RESULTS: In six GH treated patients with genetically verified PWS there was a substantial increase in lean body mass of 5 kg (p = 0.031) and a concomitant, however, non-significant, decrease in body fat of 5% (p = 0.156). The changes in the genetically verified patients without GH treatment were small and unsystematic. No compliance problems were reported. Only one non-GH-treated woman developed overt diabetes. CONCLUSION: Despite inherent behavioural problems it was possible to continue GH injections for 5 years with sustained favourable effects on body composition without clinically, significant side effects.     

Growth retardation in chronic diseases: possible mechanisms

Underwood LE. Growth retardation in chronic diseases: possible mechanisms. Acta Pædiatr 1999; Suppl 428: 93–6. Stockholm. ISSN 0803–5326
Multiple and complex mechanisms are likely to be involved in producing the growth retardation that occurs in children with chronic disease. The principal mechanisms in the pathway leading to growth arrest include too little substrate available to the child, excessive need for and over-consumption of substrate, and inefficient management of body components needed for growth. It is proposed that alterations in the growth hormone (GH)-insulin-like growth factor (IGF) system play a major role at each of the steps between insult from chronic disease and growth retardation. When substrate is insufficient, the production and action of IGF-I are attenuated at multiple points in the GH-IGF cascade. When over-consumption of substrate occurs, a situation of'internal starvation'probably develops - leading to events similar to those that take place when substrate supply is inadequate. Finally, conditions that cause inefficient management of body components needed for growth, as characterized by increased proteolysis, appear to be attenuated by GH and IGF-I. □ Chronic disease, growth hormone, growth retardation, insulin-like growth factor I     

Body composition in Prader-Willi syndrome: assessment and effects of growth hormone administration

Children and adults with Prader-Willi syndrome are usually overweight, if not obese. Nevertheless, it is now thought that the body composition exhibited by such individuals is markedly dissimilar to that found in simple obesity. In fact, the body composition typical of Prader-Willi syndrome is actually more characteristic of that found in individuals with growth hormone (GH) deficiency, namely an increased level of adiposity in the limbs in comparison with the trunk and an overall reduction in fat-free mass. This variation in body composition may impact upon the assumptions inherent in many techniques used to measure body size and body composition, such as the use of body mass index and skinfolds. Therefore, it is important that the potential error in body composition assessment is understood by professionals evaluating patients with Prader-Willi syndrome. Accurate assessment of body composition is critical in Prader-Willi syndrome, as a number of recent studies have revealed extremely similar findings relating to the effect of exogenous GH on the body composition of patients with this syndrome. Other notable findings of these studies include significant increases in muscle strength and exercise capacity, which probably result from the changes in body composition. The routine use of exogenous GH to treat this extremely debilitating syndrome should now be considered.     

Body composition in Prader-Willi syndrome: assessment and effects of growth hormone administration

Children and adults with Prader-Willi syndrome are usually overweight, if not obese. Nevertheless, it is now thought that the body composition exhibited by such individuals is markedly dissimilar to that found in simple obesity. In fact, the body composition typical of Prader-Willi syndrome is actually more characteristic of that found in individuals with growth hormone (GH) deficiency, namely an increased level of adiposity in the limbs in comparison with the trunk and an overall reduction in fat-free mass. This variation in body composition may impact upon the assumptions inherent in many techniques used to measure body size and body composition, such as the use of body mass index and skinfolds. Therefore, it is important that the potential error in body composition assessment is understood by professionals evaluating patients with Prader-Willi syndrome. Accurate assessment of body composition is critical in Prader-Willi syndrome, as a number of recent studies have revealed extremely similar findings relating to the effect of exogenous GH on the body composition of patients with this syndrome. Other notable findings of these studies include significant increases in muscle strength and exercise capacity, which probably result from the changes in body composition. The routine use of exsogenous GH to treat this extremely debilitating syndrome should now be considered.     

Transdermal estradiol priming during clonidine stimulation test in non-growth hormone deficient children with short stature: a pilot study

The diagnosis of growth hormone (GH) deficiency is strongly influenced by age, body mass index and presence of gonadal steroids. Priming with oral estradiol (E2) is one possible way to overcome the impact of variable levels of sex steroids. We describe the effects of transdermal estradiol (E2-t) priming on GH response after clonidine stimulation in prepubertal children with familial short stature (group 1, n = 12) or constitutional growth delay (group 2, n = 22). All patients underwent a clonidine test (0.1 mg/m2, p.o.) followed by a clonidine plus E2-t test (50 microg/day) with a 7-day interval. Before E2-t, basal GH and insulin-like growth factor-I (IGF-I) values were similar in the two groups. After E2-t priming, basal GH was significantly higher only in group 2. When compared with group 1, patients from group 2 had a significant increase of GH peak response when submitted to E2-t. The number of patients in both groups with adequate GH peak response was higher after E2-t priming. We conclude that E2-t priming is able to increase GH peak response after clonidine stimulation and also improves the accuracy of the clonidine test in the diagnosis of GH deficiency. Compared to oral administration, E2-t delivery can prevent liver toxicity, providing a more physiological mechanism of GH secretion.     

Gender does not influence prepubertal growth velocity during standard growth hormone therapy--analysis of United States KIGS data

BACKGROUND: Gender is an important determinant that affects the ultimate dose of growth hormone (GH) used for replacement in adult GH deficiency (GHD). Women require larger doses of GH per body weight to achieve comparable age-adjusted serum IGF-I concentrations than do men. OBJECTIVE: To test whether this is entirely a sex steroid effect or biologically inherent in gender. PATIENTS AND METHODS: We examined growth response to GH (0.25-0.35 mg/kg/week) during the first 2 years of therapy in 147 children (44 girls), and in the first 3 years of therapy in 83 of these children (23 girls). Children were aged 3-8 years at onset of therapy, had peak stimulated GH <10 microg/l, and were reported to be prepubertal during the period of analysis. RESULTS: In the relative absence of sex steroid, there was no gender difference in growth velocity SDS or gain in height SDS during 2 or 3 years of GH therapy. CONCLUSIONS: Inherent gender differences in linear growth response to GH prior to puberty may exist, but are not evident in the first years of GH therapy at this GH dose.     

Longitudinal study of physiologic insulin resistance and metabolic changes of puberty

Cross-sectional studies have shown that 1) adolescents are insulin resistant compared with prepubertal children and adults, 2) pubertal insulin resistance is likely mediated by growth hormone (GH), and 3) pubertal insulin resistance is associated with increased fat oxidation and decreased glucose oxidation. The aim of this study was to assess the validity of these cross-sectional observations by performing a longitudinal study in normal children during the prepubertal and pubertal periods. Nine healthy, normal weight, prepubertal children underwent hyperinsulinemic-euglycemic and hyperglycemic clamp studies for evaluation of insulin sensitivity and insulin secretion. Children had repeat evaluations during puberty. Consistent with cross-sectional observations, this longitudinal study demonstrated that during puberty: 1) insulin sensitivity decreased by approximately 50%, 2) the decrease in insulin sensitivity was compensated by a doubling in insulin secretion, and 3) the decrease in insulin sensitivity was independent of changes in percentage of body fat. Puberty was associated with increased total body lipolysis and decreased glucose oxidation. A novel observation is the demonstration of approximately 50% decrease in adiponectin levels at the pubertal time point. These metabolic changes are proposed to be partially mediated by increased GH secretion and are consistent with the Randle cycle of competition between glucose and fat oxidation.     

Sustained benefit after 2 years of growth hormone on body composition, fat utilization, physical strength and agility, and growth in Prader-Willi syndrome

BACKGROUND: Obesity and hypotonia in children with Prader-Willi syndrome (PWS) are accompanied by abnormal body composition resembling a growth hormone (GH)-deficient state. Hypothalamic dysfunction in PWS includes decreased GH secretion, suggesting a possible therapeutic role for GH treatment. Although recent studies have demonstrated short-term benefits of treatment with GH, a critical question is whether beneficial changes persist or wane with prolonged therapy. OBJECTIVES AND METHODS: Effects of 24 months of GH treatment (1 mg/m(2)/d) on growth, body composition, strength and agility, pulmonary function, resting energy expenditure, and fat utilization were assessed in 35 children with PWS. Percent body fat, lean muscle mass, and bone mineral density were measured by dual-energy x-ray absorptiometry. Indirect calorimetry was used to determine resting energy expenditure and to calculate the respiratory quotient. RESULTS: Compared with baseline evaluations, increased height velocity (SD score -1.1 +/- 2.5 to 2.2 +/- 2.3; P <. 001), reduced percent body fat (46.4% +/- 8.4% to 40.3% +/- 10.0%, P <.001), and improved respiratory muscle function and physical strength and agility (sit-ups, weight-lifts, running speed, and broad jump; P <.01) were observed after 24 months of GH treatment. A decline in respiratory quotient (0.81 +/- 0.07 to 0.75 +/- 0.06; P <. 01) and a trend toward increased resting energy expenditure were also observed. Changes in response to GH occurred predominantly during the initial 12 months of GH therapy. CONCLUSIONS: Children with PWS had sustained increases in lean body mass, decreases in percent body fat, improvements in physical strength and agility, and increased fat oxidation after 24 months of GH therapy. However, between 12 and 24 months, the growth rate slowed. Consequently, encouraging initial results require even more prolonged study to draw conclusions regarding the long-term value of GH therapy in changing body composition in children with PWS.     

Growth hormone improves mobility and body composition in infants and toddlers with Prader-Willi syndrome

OBJECTIVES: To determine the effect of growth hormone (GH) on body composition and motor development in infants and toddlers with Prader-Willi syndrome (PWS). STUDY DESIGN: Twenty-nine subjects with PWS (4-37 months of age) were randomized to GH treatment (1mg/m 2 /day) or observation for 12 months. Percent body fat, lean body mass, and bone mineral density were measured by dual x-ray absorptiometry; energy expenditure was measured by deuterium dilution; and motor constructs of mobility (M) and stability (S) were assessed using the Toddler Infant Motor Evaluation (TIME). RESULTS: GH-treated subjects, compared with controls, demonstrated decreased percent body fat (mean, 22.6% +/- 8.9% vs 28.5% +/- 7.9%; P < .001), increased lean body mass (mean, 9.82 +/- 1.9 kg vs 6.3 +/- 1.9 kg; P < .001), and increased height velocity Z scores (mean, 5. 0 +/- 1.8 vs 1.4 +/- 1.0; P < .001). Patients who began GH before 18 months of age showed higher mobility skill acquisition compared with controls within the same age range (mean increase in raw score, 284 +/- 105 vs 206 +/- 63; P < .05). CONCLUSIONS: GH treatment of infants and toddlers with PWS for 12 months significantly improves body composition and when begun before 18 months of age increases mobility skill acquisition. These results suggest that GH therapy instituted early in life may lessen deterioration of body composition in PWS while also accelerating motor development.     

Metabolic effects of discontinuing growth hormone treatment.

AIMS: To evaluate the effects of discontinuing growth hormone (GH) treatment on energy expenditure and body composition, which might help predict those most likely to benefit from early reintroduction of GH treatment in young adult life. METHODS: Body composition was calculated from skinfold thicknesses and dual energy x ray absorptometry (DXA). Resting metabolic rate (RMR) and whole body bone mineral content (BMC) were also measured. Measurements were made before stopping treatment, at discontinuation of GH treatment, and two weeks, six months, and one year later in 11 adolescents with growth hormone deficiency (GHD) and five adolescents without GHD who were treated with GH. Measurements were compared with 10 healthy controls, in whom measurements were repeated one year later. RESULTS: During the nine months before discontinuation of GH there were no changes in body composition, RMR, or BMC of patients with GHD, nor differences when compared with controls. RMR was reduced by 11.3 kJ/kg fat free mass two weeks after stopping GH in GHD patients and remained suppressed thereafter compared with controls. Percentage body fat increased by 4.3%/year in patients with GHD after discontinuing GH, whereas no changes were noted in control or non-GHD patients at one year. The patients experiencing the greatest reductions in RMR/kg fat free mass at six months showed the largest increases in body fat at one year. No change in BMC was noted in patients one year after stopping treatment. CONCLUSION: Important metabolic changes occur early after discontinuing GH treatment. In patients whose growth is complete, these changes might be used to predict those most likely to benefit from continuation of GH treatment into adult life.     

Nutrient intake and body composition variables in Prader-Willi syndrome--effect of growth hormone supplementation and genetic subtype

In patients with Prader-Willi syndrome (PWS), limited information exists on the effects of growth hormone (GH) therapy, gender and genetic subtype on nutrient intake and body composition. We therefore compared GH-treated and nontreated patients, taking into account Tanner stage, gender, and genetic form. PATIENTS AND METHODS: In 37 individuals with PWS (20/17 M/F; 21/16 GH+/GH-), dietary intake and body composition (BMI, DEXA) were assessed. RESULTS: Older GH-treated children (Tanner stage 3-4) displayed improved body composition variables (BMI, total and percentage fat mass, truncal fat) (p < 0.05), despite dietary intake similar to non-treated patients; younger children (Tanner stage 1-2) displayed a different pattern, despite greater total caloric and fat intake (p < 0.05) with GH treatment, with only minor differences in body composition. Genetic form and gender had no intrinsic effect on nutrient intake or body composition. CONCLUSION: In 37 patients with PWS, GH treatment selectively affected body composition (BMI, fat mass), and dietary fat intake based on patients' developmental status, while these variables were unaffected by gender or genetic subtype.     

Growth hormone improves body composition and motor development in infants with Prader-Willi syndrome after six months

BACKGROUND: Infants with Prader-Willi syndrome (PWS) show abnormalities of body composition. Children with PWS treated with growth hormone (GH) demonstrate improved body composition and motor skills. OBJECTIVE: To assess body composition and motor changes in infants with PWS following 6 months GH therapy. METHODS: Twenty-five infants with PWS (mean age 15.5 mo) underwent dual energy X-ray absorptiometry (DEXA) assessment of body composition, and motor assessment with the Toddler Infant Motor Evaluation (TIME). Patients were then randomized to treatment (Genotropin, 1 mg/m2/day) or control, with reassessment at 6 months. RESULTS: GH treatment significantly increased lean body mass (6.4 +/- 2.4 kg to 8.9 +/- 2.7 kg) and decreased body fat (27.6 +/- 9.9% to 22.4 +/- 10.3%). Age equivalent motor scores improved 4 months in the treated group vs 2 months in controls (p < 0.01). CONCLUSIONS: Infants with PWS show significant body composition and motor development improvement following 6 months GH therapy. We are investigating whether this improvement leads to long-term reductions in obesity.     

Effects of growth hormone therapy on bone mass, metabolic balance, and well-being in young adult survivors of childhood acute lymphoblastic leukemia

Growth hormone deficiency (GHD), mostly after cranial radiotherapy (CRT), may lead to several negative effects. Young adult survivors of acute lymphoblastic leukemia (ALL) could benefit from GH therapy in different ways. Twenty ALL survivors (17.1 ± 4.3 y after diagnosis) with low bone mineral densities and/or low insulin-like growth factor-1 were included. Two of the 3 patients who only received chemotherapy had GHD. Of the 20 patients, 17 started with GH therapy and 14 completed the 2-year study period. At several time points, bone mineral density (BMD) was measured. Psychological functioning was assessed. At the start of the study, standard deviation scores of height, insulin-like growth factor-1, lumbar spine, and femoral neck BMD were all below -1. After 2 years of GH therapy, total body BMD and lean mass were significantly higher (P < 0.01 and P < 0.001, respectively), whereas the percentage fat was significantly lower (P < 0.02). Several psychological measures improved significantly after 2 years. In conclusion, GH therapy during 2 years in young adult survivors of childhood ALL did have a number of benefits, such as improvement of total body bone density and body composition. Results also suggest improvement of psychological well being. Furthermore, it also became clear that patients after chemotherapy alone should be tested for GHD.