GH/IGF-I axis in Prader-Willi syndrome: evaluation of IGF-I levels and of the somatotroph responsiveness to various provocative stimuli. Genetic Obesity Study Group of Italian Society of Pediatric Endocrinology and Diabetology

Endocrine features of Prader-Willi syndrome: a narrative review focusing on genotype-phenotype correlation

Prader-Willi syndrome (PWS) is a complex genetic disorder caused by three different types of molecular genetic abnormalities. The most common defect is a deletion on the paternal 15q11-q13 chromosome, which is seen in about 60% of individuals. The next most common abnormality is maternal disomy 15, found in around 35% of cases, and a defect in the imprinting center that controls the activity of certain genes on chromosome 15, seen in 1-3% of cases. Individuals with PWS typically experience issues with the hypothalamic-pituitary axis, leading to excessive hunger (hyperphagia), severe obesity, various endocrine disorders, and intellectual disability. Differences in physical and behavioral characteristics between patients with PWS due to deletion versus those with maternal disomy are discussed in literature. Patients with maternal disomy tend to have more frequent neurodevelopmental problems, such as autistic traits and behavioral issues, and generally have higher IQ levels compared to those with deletion of the critical PWS region. This has led us to review the pertinent literature to investigate the possibility of establishing connections between the genetic abnormalities and the endocrine disorders experienced by PWS patients, in order to develop more targeted diagnostic and treatment protocols. In this review, we will review the current state of clinical studies focusing on endocrine disorders in individuals with PWS patients, with a specific focus on the various genetic causes. We will look at topics such as neonatal anthropometry, thyroid issues, adrenal problems, hypogonadism, bone metabolism abnormalities, metabolic syndrome resulting from severe obesity caused by hyperphagia, deficiencies in the GH/IGF-1 axis, and the corresponding responses to treatment.

Clinical Characteristics and Growth Hormone Treatment in Patients with Prader-Willi Syndrome

OBJECTIVE

To investigate clinical characteristics and response to growth hormone (GH) treatment in patients with Prader-Willi syndrome (PWS) in Turkey.

METHODS

The data of 52 PWS patients from ten centers was retrospectively analyzed. A nation-wide, web-based data system was used for data collection. Demographic, clinical, genetic, and laboratory data and follow-up information of the patients were evaluated.

RESULTS

The median age of patients at presentation was 1.5 years, and 50% were females. Genetic analysis showed microdeletion in 69.2%, uniparental disomy in 11.5%, imprinting defect in 1.9% and methylation abnormality in 17.3%. Hypotonia (55.7%), feeding difficulties (36.5%) and obesity (30.7%) were the most common complaints. Cryptorchidism and micropenis were present in 69.2% and 15.3% of males, respectively. At presentation, 25% had short stature, 44.2% were obese, 9.6% were overweight and 17.3% were underweight. Median age of obese patients was significantly higher than underweight patients. Central hypothyroidism and adrenal insufficiency were present in 30.7% and 4.7%, respectively. Hypogonadism was present in 75% at normal age of puberty. GH treatment was started in 40% at a mean age of 4.7±2.7 years. After two years of GH treatment, a significant increase in height SDS was observed. However, body mass index (BMI) standard deviation (SDS) remained unchanged.

CONCLUSION

The most frequent complaints were hypotonia and feeding difficulty at first presentation. Obesity was the initial finding in 44.2%. GH treatment was started in less than half of the patients. While GH treatment significantly increased height SDS, BMI SDS remained unchanged, possibly due to the relatively older age at GH start.

Human Growth and Growth Hormone: From Antiquity to the Recominant Age to the Future

Since antiquity Man has been fascinated by the variations in human (and animal) growth. Stories and art abound about giants and little people. Modern genetics have solved some of etiologies at both extremes of growth. Serious study began with the pathophysiology of acromegaly followed by early attempts at treatment culminating in modern endoscopic surgery and multiple pharmacologic agents. Virtually at the same time experiments with the removal of the pituitary from laboratory animals noted the slowing or stopping of linear growth and then over a few decades the extraction and purification of a protein within the anterior pituitary that restored, partially or in full, the animal's growth. Human growth hormone was purified decades after those from large animals and it was noted that it was species specific, that is, only primate growth hormone was metabolically active in primates. That was quite unlike the beef and pork insulins which revolutionized the care of children with diabetes mellitus. A number of studies included mild enzymatic digestion of beef growth hormone to determine if those "cores" had biologic activity in primates and man. Tantalizing data showed minimal but variable metabolic efficacy leading to the "active core" hypothesis, for these smaller peptides would be amenable to peptide synthesis in the time before recombinant DNA. Recombinant DNA changed the landscape remarkably promising nearly unlimited quantities of metabolically active hormone. Eight indications for therapeutic use have been approved by the Food and Drug Administration and a large number of clinical trials have been undertaken in multiple other conditions for which short stature in childhood is a sign. The future predicts other clinical indications for growth hormone therapy (and perhaps other components of the GH?IGF-1 axis), longer-acting analogues and perhaps a more physiologic method of administration as virtually all methods at present are far from physiologic.

Effects of Bifidobacterium animalis Subsp. lactis (BPL1) Supplementation in Children and Adolescents with Prader-Willi Syndrome: A Randomized Crossover Trial

Prader-Willi syndrome (PWS) is a rare genetic disorder characterized by a wide range of clinical manifestations, including obesity, hyperphagia, and behavioral problems. Bifidobacterium animalis subsp. lactis strain BPL1 has been shown to improve central adiposity in adults with simple obesity. To evaluate BPL1's effects in children with PWS, we performed a randomized crossover trial among 39 patients (mean age 10.4 years). Participants were randomized to placebo-BPL1 (n = 19) or BPL1-placebo (n = 20) sequences and underwent a 12-week period with placebo/BPL1 treatments, a 12-week washout period, and a 12-week period with the crossover treatment. Thirty-five subjects completed the study. The main outcome was changes in adiposity, measured by dual-energy X-ray absorptiometry. Secondary outcomes included lipid and glucose metabolism, hyperphagia, and mental health symptoms. Generalized linear modeling was applied to assess differences between treatments. While BPL1 did not modify total fat mass compared to placebo, BPL1 decreased abdominal adiposity in a subgroup of patients older than 4.5 years (n = 28). BPL1 improved fasting insulin concentration and insulin sensitivity. Furthermore, we observed modest improvements in some mental health symptoms. A follow-up trial with a longer treatment period is warranted to determine whether BPL1 supplementation can provide a long-term therapeutic approach for children with PWS (ClinicalTrials.gov NCT03548480).

Uniparental disomy and pretreatment IGF-1 may predict elevated IGF-1 levels in Prader-Willi patients on GH treatment

Pediatric patients with Prader-Willi syndrome (PWS) can be treated with recombinant human GH (rhGH). These patients are highly sensitive to rhGH and the standard doses suggested by the international guidelines often result in IGF-1 above the normal range. We aimed to evaluate 1 the proper rhGH dose to optimize auxological outcomes and to avoid potential overtreatment, and 2 which patients are more sensitive to rhGH. In this multicenter real-life study, we recruited 215 patients with PWS older than 1 year, on rhGH at least for 6 months, from Italian Centers for PWS care. We collected auxological parameters, rhGH dose, IGF-1 at recruitment and (when available) at start of treatment. The rhGH dose was 4.3 (0.7/8.4) mg/m²/week. At recruitment, IGF-1 was normal in 72.1% and elevated in 27.9% of the patients. In the group of 115 patients with IGF-1 available at start of rhGH, normal pretreatment IGF-1 and uniparental disomy were associated with elevated IGF-1 during the therapy. No difference in height and growth velocity was found between patients treated with the highest and the lowest range dose. The rhGH dose prescribed in Italy seems lower than the recommended one. Normal pretreatment IGF-1 and uniparental disomy are risk factors for elevated IGF-1. The latter seems to be associated with higher sensitivity to GH. In case of these risk factors, we recommend a more accurate titration of the dose to avoid overtreatment and its potential side effects.

Prevalence of growth hormone (GH) deficiency in previously GH-treated young adults with Prader-Willi syndrome

OBJECTIVE

Some features of subjects with Prader-Willi syndrome (PWS) resemble those seen in growth hormone deficiency (GHD). Children with PWS are treated with growth hormone (GH), which has substantially changed their phenotype. Currently, young adults with PWS must discontinue GH after attainment of adult height when they do not fulfil the criteria of adult GHD. Limited information is available about the prevalence of GHD in adults with PWS. This study aimed to investigate the GH/insulin-like growth factor (IGF-I) axis and the prevalence of GHD in previously GH-treated young adults with PWS.

DESIGN

Cross-sectional study in 60 young adults with PWS.

MEASUREMENTS

Serum IGF-I and IGFBP-3 levels, GH peak during combined growth hormone-releasing hormone (GHRH)-arginine stimulation test.

RESULTS

Serum IGF-I was <-2 standard deviation scores (SDS) in 2 (3%) patients, and IGFBP-3 was within the normal range in all but one patient. Median (IQR) GH peak was 17.8 μg/L (12.2; 29.7) [~53.4 mU/L] and below 9 μg/L in 9 (15%) patients. Not one patient fulfilled the criteria for adult GHD (GH peak < 9 μg/L and IGF-I < -2 SDS), also when BMI-dependent criteria were used. A higher BMI and a higher fat mass percentage were significantly associated with a lower GH peak. There was no significant difference in GH peak between patients with a deletion or a maternal uniparental disomy (mUPD).

CONCLUSIONS

In a large group of previously GH-treated young adults with PWS, approximately 1 in 7 exhibited a GH peak <9 μg/L during a GHRH-arginine test. However, none of the patients fulfilled the consensus criteria for adult GHD.

Growth hormone therapy for Prader-willi syndrome: challenges and solutions

Prader-Willi syndrome (PWS) is characterized by a dysregulation of growth hormone (GH)/insulin-like growth factor I axis, as the consequence of a complex hypothalamic involvement. PWS' clinical picture seems to resemble the classic non-PWS GH deficiency (GHD), including short stature, excessive body fat, decreased muscle mass, and impaired quality of life. GH therapy is able to ameliorate the phenotypic appearance of the syndrome, as well as to improve body composition, physical strength, and cognitive level. In this regard, however, some pathophysiologic and clinical questions still remain, representing a challenge to give the most appropriate care to PWS patients. Data about the prevalence of GHD in PWS children are not unequivocal, ranging from 40% to 100%. In this context, to establish whether the presence (or not) of GHD may have a different effect on clinical course during GH therapy may be helpful. In addition, the comparison of GH effects in PWS children diagnosed as small for gestational age with those obtained in subjects born appropriate for gestational age is of potential interest for future trials. Emerging information seems to demonstrate the maintenance of beneficial effects of GH therapy in PWS subjects after adolescent years. Thus, GH retesting after achievement of final height should be taken into consideration for all PWS patients. However, it is noteworthy that GH administration exerts positive effects both in PWS adults with and without GHD. Another critical issue is to clarify whether the genotype-phenotype correlations may be relevant to specific outcome measures related to GH therapy. Moreover, progress of our understanding of the role of GH replacement and concomitant therapies on bone characteristics of PWS is required. Finally, a long-term surveillance of benefits and risks of GH therapy is strongly recommended for PWS population, since most of the current studies are uncontrolled and of short duration.

Somatropin therapy for children with prader-willi syndrome : guidelines for use

Prader-Willi syndrome is a neurogenetic disorder that occurs due to the lack of a paternally expressed gene or genes on chromosome 15q11-q13. Many of the symptoms present in Prader-Willi syndrome are due to a hypothalamic-pituitary dysfunction. The main characteristics are muscular hypotonia, delayed psychomotor development, insatiable appetite resulting in overweight if a diet is not maintained, compromised growth and puberty resulting in a short final height and incomplete sexual development, respiratory disturbances, and dysmorphic features. Individuals with Prader-Willi syndrome have compromised growth and abnormal body composition with increased fat mass, decreased lean body mass, and low bone density, resembling a growth hormone-deficient status. Somatropin treatment has a beneficial effect on growth with increased final height and an improvement in and maintenance of body composition, as well as a beneficial effect on respiratory functions. Before initiating somatropin therapy, weight should be kept at an appropriate level, and polysomnography, as well as an otorhinolaryngologic examination should be performed. During somatropin therapy, carbohydrate metabolism and the development of scoliosis should be monitored, as well as bodyweight.A comprehensive team to manage the various components of medical, psychologic, and sociologic care is required for individuals with Prader-Willi syndrome.

Positive effect of growth hormone treatment in maternal uniparental disomy chromosome 14

OBJECTIVE

Maternal uniparental disomy of chromosome 14 (matUPD(14)) resembles Prader-Willi syndrome (PWS). As positive effects of growth hormone (GH) are observed in individuals with PWS, treatment with GH may be useful in individuals with matUPD(14) as well. The aim of this study was to investigate the effect of GH treatment on growth and body composition in children with matUPD(14).

DESIGN

This is a prospective observational study of GH treatment in two girls with matUPD(14) during 2 years, and spontaneous growth in another matUPD(14) girl of similar age.

PATIENTS

Three girls (patient A, B and C, aged 8·9, 11·4 and 12·7 years, respectively) with matUPD(14) were included in this study.

MEASUREMENTS

Patients A and B were treated with GH during 2 years. Patient C was not treated with GH, as she was diagnosed at an age at which she attained near-final height. Main outcome measures included height, weight, body proportions, IGF-1, bone age, and DXA scan for body composition.

RESULTS

In both treated girls, a considerable increase in height (from -2·3SD and -1·2SD to -1·2SD and -0·6SD, respectively) and IGF-1 levels (from +0·1SD and -1·4SD to +1·3SD and +0·9SD, respectively) and, in patient A, a decrease in weight (+1·2 SD to -0·7SD), and improved body composition (fat percentage from 51·5% to 45·4%) were found. Both experienced improved muscle strength.

CONCLUSIONS

GH treatment in matUPD(14) cases can show beneficial effects on growth and body composition if started in time. Larger, international studies to determine detailed effectivity and side effects are suggested.

Long-term side effects of growth hormone treatment in children with Prader-Willi syndrome

The main motivations of growth hormone (GH) treatment of Prader-Willi syndrome (PWS) are the stimulation of growth and lean muscle mass. Furthermore GH therapy in Prader-Willi children seems to favorably affect their behavior and mental performances. It is still a matter of discussion whether GH therapy in PWS should be considered responsible for specific adverse events. The most significant of them are scoliosis and breathing disorders, the latter considered being responsible for some deaths, reported in children with PWS, mainly at the beginning of GH therapy. Obstructive sleep apnea was occasionally reported also in patients treated with GH for several years. The review reports and discusses the latest data related to side effects of long-term GH treatment in children with PWS.

Growth hormone treatment in non-growth hormone-deficient children

Until 1985 growth hormone (GH) was obtained from pituitary extracts, and was available in limited amounts only to treat severe growth hormone deficiency (GHD). With the availability of unlimited quantities of GH obtained from recombinant DNA technology, researchers started to explore new modalities to treat GHD children, as well as to treat a number of other non-GHD conditions. Although with some differences between different countries, GH treatment is indicated in children with Turner syndrome, chronic renal insufficiency, Prader-Willi syndrome, deletions/mutations of the SHOX gene, as well as in short children born small for gestational age and with idiopathic short stature. Available data from controlled trials indicate that GH treatment increases adult height in patients with Turner syndrome, in patients with chronic renal insufficiency, and in short children born small for gestational age. Patients with SHOX deficiency seem to respond to treatment similarly to Turner syndrome. GH treatment in children with idiopathic short stature produces a modest mean increase in adult height but the response in the individual patient is unpredictable. Uncontrolled studies indicate that GH treatment may be beneficial also in children with Noonan syndrome. In patients with Prader-Willi syndrome GH treatment normalizes growth and improves body composition and cognitive function. In any indication the response to GH seems correlated to the dose and the duration of treatment. GH treatment is generally safe with no major adverse effects being recorded in any condition.

GrowthHormone Research Society workshop summary: consensus guidelines for recombinant human growth hormone therapy in Prader-Willi syndrome

CONTEXT

Recombinant human GH (rhGH) therapy in Prader-Willi syndrome (PWS) has been used by the medical community and advocated by parental support groups since its approval in the United States in 2000 and in Europe in 2001. Its use in PWS represents a unique therapeutic challenge that includes treating individuals with cognitive disability, varied therapeutic goals that are not focused exclusively on increased height, and concerns about potential life-threatening adverse events.

OBJECTIVE

The aim of the study was to formulate recommendations for the use of rhGH in children and adult patients with PWS.

EVIDENCE

We performed a systematic review of the clinical evidence in the pediatric population, including randomized controlled trials, comparative observational studies, and long-term studies (>3.5 y). Adult studies included randomized controlled trials of rhGH treatment for ≥ 6 months and uncontrolled trials. Safety data were obtained from case reports, clinical trials, and pharmaceutical registries.

METHODOLOGY

Forty-three international experts and stakeholders followed clinical practice guideline development recommendations outlined by the AGREE Collaboration (www.agreetrust.org). Evidence was synthesized and graded using a comprehensive multicriteria methodology (EVIDEM) (http://bit.ly.PWGHIN).

CONCLUSIONS

Following a multidisciplinary evaluation, preferably by experts, rhGH treatment should be considered for patients with genetically confirmed PWS in conjunction with dietary, environmental, and lifestyle interventions. Cognitive impairment should not be a barrier to treatment, and informed consent/assent should include benefit/risk information. Exclusion criteria should include severe obesity, uncontrolled diabetes mellitus, untreated severe obstructive sleep apnea, active cancer, or psychosis. Clinical outcome priorities should vary depending upon age and the presence of physical, mental, and social disability, and treatment should be continued for as long as demonstrated benefits outweigh the risks.

Growth hormone: the expansion of available products and indications

Growth hormone is a widely used hormone. This article describes its historical use, current indications and studies for possible future uses.

The relationship between IGF-I concentration, cognitive function and quality of life in adults with Prader-Willi syndrome

Mental retardation is one of the clinical characteristics of Prader-Willi syndrome (PWS) and in part of the patients growth hormone deficiency is demonstrable. Cognitive function seems to be influenced by insulin-like growth factor I (IGF-I); however, little is known about cognitive function in relation to IGF-I levels in PWS adults. The aim of the present study was to evaluate cognitive function in adult PWS patients in comparison to healthy siblings and to investigate whether there is a correlation between cognitive function and IGF-I levels. Anthropometric measurements, IGF-I levels, quality of life (QoL), Appetite Assessment Score, IQ (GIT and Raven) and cognitive function (by four subtests of the Cambridge Neuropsychological Automated Testing Battery, CANTAB) were evaluated in PWS patients and their healthy siblings served as control group. PWS patients had significantly lower IGF-I levels, IQ and QoL when compared to controls. Reaction times were longer and performance was worse on CANTAB subtests in PWS adults. IGF-I on one hand and IQ, Appetite Assessment Score and cognitive performance on the other hand seem to be correlated in PWS patients. In conclusion, IGF-I levels, IQ and QoL are significantly lower in PWS subjects when compared to healthy siblings. In PWS adults, temporal as well as prefrontal cognitive functions are impaired. Higher IGF-I levels appear to be related to better intellectual skills and faster temporal memory processing in PWS patients.

Psychiatric adverse effects of rimonobant in adults with Prader Willi syndrome

BACKGROUND

Prader Willi syndrome (PWS) without strict environmental modifications can lead to obesity associated with significant morbidity and mortality. In addition to increased appetite, these individuals have decreased energy expenditure with lower insulin like growth factor 1 (IGF1), which contributes to adiposity. No effective treatment is available for this condition. Endocannabinoid receptor CB1 antagonist, rimonobant, has been effective for treatment of obesity in adult subjects. Rimonabant promotes weight loss by multiple proposed mechanisms, including decreased appetite and lipogenesis, and increased energy expenditure. Therefore, we conducted this pilot study to evaluate the effect of rimonabant on body weight and composition of adults with PWS.

METHOD

This was a double blind placebo controlled study. Body weight, total fat mass, fasting ghrelin, leptin, IGF1 and insulin like growth factor binding protein (IGFBP-3) were collected at baseline, and after 90 and 180 days of treatment with placebo or 20 mg of rimonabant.

RESULTS

Due to psychiatric adverse effects, 50% of subjects in the rimonabant group withdrew, and the study was terminated early (N=10) for safety concerns. There was a trend for weight loss, lower fat mass and higher IGF1 level at the end of study in this group. Leptin followed the fat mass and decreased with rimonabant treatment.

CONCLUSION

Rimonabant administration may be efficacious for weight loss in adults with PWS; unfortunately it is associated with an unacceptably high risk of psychiatric side effects. Future CB1 antagonists will need a better psychiatric profile before considered in the treatment of obesity in this genetic condition.

Long-term effects of growth hormone therapy on patients with Prader-Willi syndrome

AIM

To assess the effects of recombinant human growth hormone (rhGH) treatment in children with Prader-Willi syndrome.

DESIGN

A 1-year study and an observational follow-up visit 10 years later.

METHODS

In 20 patients with Prader-Willi syndrome (PWS): clinical assessment, laboratory tests, body composition analysis by dual energy X-ray absorptiometry, sleep polygraphy, health-related quality of life assessed by 16D.

RESULTS

Only two patients had normal growth hormone secretion at baseline. All patients were significantly shorter than their expected heights, but experienced catch-up growth during growth hormone treatment. At follow-up, 13 patients had reached adult heights and were markedly taller than historical controls. The cumulative dose of rhGH over 10 years correlated inversely with the total body fat percentage (p = 0.033). However, patients remained severely obese at 10 years. Sleep polygraphy was abnormal in more than half of the patients. Health-related quality of life of the patients remained substantially below that of normal population.

CONCLUSION

Growth hormone markedly improved adult height in subjects with PWS when compared to historical data. The cumulative dose of growth hormone correlated with reduction in body fat; nevertheless, patients remained severely obese.

Long-term growth hormone therapy changes the natural history of body composition and motor function in children with prader-willi syndrome

BACKGROUND

Children with Prader-Willi syndrome (PWS) have decreased muscle mass, hypotonia, and impaired linear growth. Recombinant human GH (hGH) treatment reportedly improves body composition and physical function in children with PWS, but these studies lack long-term control data. To assess the impact of hGH therapy begun early in life on the natural history of PWS, we compared height, body composition, and strength in similar-age children with PWS naïve to hGH with those treated with hGH for 6 yr.

OBJECTIVES

Forty-eight children with PWS were studied: 21 subjects (aged 6-9 yr) treated with hGH for 6 yr (beginning at 4-32 months, mean 13 +/- 6 months) were compared with 27 children of similar age (5-9 yr) prior to treatment with hGH. Percent body fat, lean body mass, carbohydrate/lipid metabolism, and motor strength were compared using analysis of covariance.

RESULTS

PWS children treated with hGH demonstrated lower body fat (mean, 36.1 +/- 2.1 vs. 44.6 +/- 1.8%, P < 0.01), greater height (131 +/- 2 vs. 114 +/- 2 cm; P < 0.001), greater motor strength [increased standing broad jump 22.9 +/- 2.1 vs. 14.6 +/- 1.9 in. (P < 0.001) and sit-ups 12.4 +/- 0.9 vs. 7.1 +/- 0.7 in 30 sec (P < 0.001)], increased high-density lipoprotein cholesterol (58.9 +/- 2.6 vs. 44.9 +/- 2.3 mg/dl, P < 0.001), decreased low-density lipoprotein (100 +/- 8 vs. 131 +/- 7 mg/dl, P < 0.01), and no difference in fasting glucose or insulin.

CONCLUSIONS

hGH treatment in children with PWS, begun prior to 2 yr of age, improves body composition, motor function, height, and lipid profiles. The magnitude of these effects suggests that long-term hGH therapy favorably alters the natural history of PWS to an extent that exceeds risks and justifies consideration for initiation during infancy.

Efficacy and safety of long-term continuous growth hormone treatment in children with Prader-Willi syndrome

BACKGROUND

Children with Prader-Willi syndrome (PWS) have abnormal body composition and impaired growth. Short-term GH treatment has beneficial effects.

OBJECTIVES

The aim of the study was to investigate effects of long-term continuous GH treatment on body composition, growth, bone maturation, and safety parameters.

SETTING

We conducted a multicenter prospective trial.

DESIGN

Fifty-five children with a mean +/- sd age of 5.9 +/- 3.2 yr were followed during 4 yr of continuous GH treatment (1 mg/m(2) . d). Data were annually obtained in one center: fat percentage (fat%) and lean body mass (LBM) by dual-energy x-ray absorptiometry, height, weight, head circumference, bone age, blood pressure, and fasting IGF-I, IGF binding protein-3, glucose, insulin, glycosylated hemoglobin, total cholesterol, high-density lipoprotein, and low-density lipoprotein. sd scores (SDS) were calculated according to Dutch and PWS reference values (SDS and SDS(PWS)).

RESULTS

Fat%SDS was significantly lower after 4 yr of GH treatment (P < 0.0001). LBMSDS significantly increased during the first year (P = 0.02) but returned to baseline values the second year and remained unchanged thereafter. Mean +/- sd height normalized from -2.27 +/- 1.2 SDS to -0.24 +/- 1.2 SDS (P < 0.0001). Head circumference SDS increased from -0.79 +/- 1.0 at start to 0.07 +/- 1.1 SDS after 4 yr. BMISDS(PWS) significantly decreased. Mean +/- sd IGF-I and the IGF-I/IGF binding protein-3 ratio significantly increased to 2.08 +/- 1.1 and 2.32 +/- 0.9 SDS, respectively. GH treatment had no adverse effects on bone maturation, blood pressure, glucose homeostasis, and serum lipids.

CONCLUSIONS

Our study in children with PWS shows that 4 yr of continuous GH treatment (1 mg/m(2) . d) improves body composition by decreasing fat%SDS and stabilizing LBMSDS and head circumference SDS and normalizes heightSDS without adverse effects. Thus, long-term continuous GH treatment is an effective and safe therapy for children with PWS.

Growth hormone: the expansion of available products and indications

Growth hormone is a widely used hormone. This article describes its historical use, current indications and studies for possible future uses.

Short-term effects of growth hormone treatment on the upper airways of non severely obese children with Prader-Willi syndrome

AIMS

The aim of this study was to establish whether short-term GH treatment causes obstructive apnea in patients with Prader-Willi syndrome and normal upper airway patency.

SUBJECTS AND METHODS

We performed an observational longitudinal 6-week GH treatment study. Thirty-four non-severely obese Prader-Willi syndrome patients (20 boys, age range 0.94-11.8 yr, median 2.24 yr) entered an observational longitudinal 6-week study. Sixteen boys received recombinant human GH (rhGH) treatment; the remaining 18 represented the control group and received no treatment. Polysomnography monitoring and othorhinolaringoiatric video endoscopy were performed one night before and after 6 weeks of rhGH treatment (0.03 mg/kg body weight/day). All patients underwent auxologic assessment, fasting blood glucose, insulin and IGF-I evaluation. The main polysomnographic parameter considered was total apnea hypopnea index, consisting of two components: central apnea hypopnea index and obstructive apnea hypopnea index. All patients were free of severe or moderate upper airway obstruction when rhGH treatment began.

RESULTS

After 6 weeks of rhGH therapy, obstructive apnea hypopnea index increased in 8/16 (50%), decreased in 5/16 (31%), and did not change in 3/16 (19%) patients. The changes were not statistically significant. The rhGH-treated group did not differ from the control group for the apnea hypopnea index both before and after 6 weeks of treatment. Adenoids and tonsils showed a slight increase in 1 and 2 patients on rhGH treatment, respectively, and did not change in the untreated patients.

CONCLUSIONS

Our data show that short-term rhGH treatment does not cause restrictions of the upper airways in patients with Prader-Willi syndrome and normal upper airway patency.

Central precocious puberty and growth hormone deficiency in a boy with Prader-Willi syndrome

In Prader-Willi syndrome (PWS) hypothalamic dysfunction is the cause of hormonal disturbances, such as growth hormone deficiency (GHD), hypogonadism, and delayed or incomplete puberty. Only a few cases of central precocious puberty (CPP) have been reported. We describe an 8.8-year-old PWS boy, with microdeletion of chromosome 15q, who developed CPP. On admission, height was 131.1 cm (+0.17 SD), BMI 26.2 kg/m(2), pubic hair (Ph) 2, and testis 4.5 ml. We found increased growth velocity (7 cm/year), high testosterone levels, pubertal response to GnRH test, and advanced bone age (10.6 years). An evaluation of growth hormone (GH) secretion revealed a deficiency. Pituitary MRI was normal. LHRH analogue therapy (Leuproreline 3.75 mg/28 days i.m.) was started at 8.9 years and discontinued at 11.3 years, when the patient had bone age of 13 years. During therapy, growth velocity, testosterone, FSH, and LH peak decreased significantly, with no pubertal progression. Growth hormone therapy (0.24 mg/kg/week) was started at 9.5 years and discontinued at 15.3 years because the patient had bone age of 17 years. After interrupting LHRH therapy the patient demonstrated spontaneous pubertal progression with pubertal gonadotropin and testosterone. At 16.3 years, height was 170 cm (-0.48 SDS), BMI 36.3 kg/m(2), Ph 4, testis volume 10 ml and there was a combined hypothalamic and peripheral hypogonadism hormonal pattern (normal LH even with low testosterone and undetectable inhibin B with high FSH). To our knowledge this is the fourth male patient with genetically-confirmed PWS demonstrating CPP and GHD and the first with a long follow-up to young adulthood.

Final adult height in children with Prader-Willi syndrome with and without human growth hormone treatment

Short stature is characteristic of children with Prader-Willi syndrome (PWS). While previous studies have demonstrated acceleration of linear height velocity with growth hormone (GH) treatment, the long-term benefit on final adult height (AH) has not been reported. The objective of this study was to compare AH attained in PWS subjects with and without GH treatment. We reviewed the records of 21 children (aged 8.3 +/- 2.7 years) with PWS and confirmed GH deficiency that attained AH after receiving human GH treatment (0.25 +/- 0.06 mg/kg/week) for a period of 7.9 +/- 1.7 years. A group of 39 non-GH-treated adults with matched initial height standard deviation score (SDS) at age 6.8 +/- 1.3 years was used as control. In the GH-treated group the mean initial height and AH-SDS was -1.9 +/- 1.7 and -0.3 +/- 1.2 respectively (P < 0.0001), whereas the mean initial and AH-SDS in the control group was -1.9 +/- 1.3 and -3.1 +/- 1 respectively (P < 0.0001). Scoliosis was seen in 43% and 39% in the GH-treated and control group respectively. Premature adrenarche (PA) was noticed in 57% of GH-treated group. Six subjects in the control group but none of the GH-treated subjects developed type 2 diabetes mellitus. Our data show that administration of GH to children with PWS restores linear growth and final AH without significant adverse effects other than PA. Further studies will be necessary to determine related morbidity and mortality in individuals with PWS that reached final AH with or without GH treatment.

[Prader-Willi syndrome: metabolic aspects related to growth hormone treatment]

AIM

The focus of this study was to evaluate the metabolic profile of Prader-Willi Syndrome (PWS) patients treated with growth hormone.

PATIENTS AND METHODS

Seven patients (four boys and three girls) with ages between six years and six months and 14 years and 11 months were treated with GH 0.1 U/kg/day subcutaneous by six times a week, for two years. Anthropometric data, lipids, glucose, IGF-I and body composition were evaluated at baseline and after 12 and 24 months.

RESULTS

IGF-I levels increased in all cases. Skin folds decreased. The mean reduction in body fat was 5.0% and the mean increased in lean mass was 7.6 kg in the prepubertal patients. The pubescent girl increased 4.8 kg and showed a 5.6% decrease in fat mass. A mean gain in the bone mass was 0.07 g/cm(2) (7.3%) in prepubescent cases, and 0.02 g/cm(2) (2.0%) in the pubescent girl.

CONCLUSION

In our study GH treatment improved lean body and bone masses and had beneficial effect on lipid values.

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.

Conditional cardiovascular response to growth hormone therapy in adult patients with Prader-Willi syndrome

CONTEXT

In Prader-Willi syndrome (PWS), an altered GH secretion has been related to reduced cardiac mass and systolic function when compared with controls.

OBJECTIVES

The objective of the study was to evaluate the cardiovascular response to GH therapy in adult PWS patients.

STUDY PARTICIPANTS

Thirteen obese PWS adults (seven males and six females, aged 26.9+/-1.2 yr, body mass index 46.3+/-1.6 kg/m2) participated in the study.

METHODS

Determination of IGF-I, metabolic parameters, echocardiography, and cardioscintigraphy with dobutamine stimulation was made during 12 months GH therapy, with results analyzed by repeated-measures ANOVA.

RESULTS

GH therapy increased IGF-I (P<0.0001); decreased C-reactive protein levels (P<0.05); and improved lean mass (P<0.001), fat mass (P<0.05), and visceral fat (P<0.001). Echocardiography showed that 6- and 12-month GH therapy increased left ventricle mass in 76 and in 61% of patients, respectively (P<0.05), did not change diastolic function, and slightly decreased the left ventricle ejection fraction (LVEF) (P=0.054). Cardioscintigraphy documented stable values of LVEF throughout the study, whereas right ventricle ejection fraction decreased significantly (P<0.05) being normally responsive to dobutamine infusion. A positive association between IGF-I z-scores and LVEF occurred at the 6- and 12-month follow-up (P<0.05).

CONCLUSIONS

In PWS, GH therapy increased cardiac mass devoid of diastolic consequences. The observation of a slight deterioration of right heart function as well as the association between IGF-I and left ventricular function during GH therapy suggest the need for appropriate cardiac and hormonal monitoring in the therapeutic strategy for Prader-Willi syndrome.

Effects of Growth Hormone Therapy on Glucose Metabolism and Insulin Sensitivity Indices in Prepubertal Children with Prader-Willi Syndrome

In Prader-Willi syndrome (PWS) growth hormone therapy (GHT) improves height, body composition, agility and muscular strength. In such patients it is necessary to consider the potential diabetogenic effect of GHT, since they tend to develop type 2 diabetes, particularly after the pubertal age. The aim of our study was to investigate the effects of GHT on glucose and insulin homeostasis in PWS children. An oral glucose tolerance test (OGTT) was performed in 24 prepubertal PWS children (15 male, 9 female, age: 5.8 +/- 2.8 years), 16 were obese (group A) and 8 had normal weight (group B), before and after 2.7 +/- 1.3 years GHT (0.22 +/- 0.03 mg/kg/week) and, only at baseline, in 35 prepubertal children with simple obesity (19 male, 16 female) (group C). Fasting glucose and insulin, glucose tolerance, insulin sensitivity index (ISI), homeostasis model assessment of insulin resistance (HOMA-IR), quick insulin check index (QUICKI), area under the curves (AUC) of glucose and insulin were estimated. At the start of GHT, all PWS children were normoglycaemic and normotolerant but two developed impaired glucose tolerance after 2.2 and 1.9 years of therapy, respectively. At baseline, group A showed lower fasting insulin levels, HOMA-IR and AUC of insulin, higher ISI, QUICKI and AUC of glucose than group C. Comparing groups A and B, AUC of insulin was higher and ISI lower in group A. During GHT, a significant increase of fasting insulin and glucose, a worsening of insulin resistance (HOMA-IR) and insulin sensitivity (QUICKI) was found only in group A while ISI did not change. The AUC of glucose decreased in both groups instead AUC of insulin did not change. BMI-SDS decreased in group A and increased in group B. The increased insulin resistance and decreased insulin sensitivity in obese PWS patients, as well as the occurrence of impaired glucose tolerance during GHT, suggest that a close monitoring of glucose and insulin homeostasis is mandatory, especially in treated obese PWS children.

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.

Growth hormone treatment in children: review of safety and efficacy

Since the advent of growth hormone (GH), the pediatric applications of GH therapy have expanded. Children with a wide variety of growth disorders have received GH treatment. The therapeutic effects and safety profile of GH in a number of pediatric conditions are reviewed, including GH deficiency (GHD), Turner syndrome, chronic renal failure, children born small for gestational age, Prader-Willi syndrome, juvenile chronic arthritis, and cystic fibrosis. GH therapy has been clearly shown to improve height velocity during childhood in a variety of pediatric conditions in which growth is compromised. There is now data that confirms GH treatment also improves final height in a number of diagnostic subgroups. Early initiation and individualization of GH treatment has the potential to normalize childhood growth in children with idiopathic GHD and enable them to achieve their genetic target height in a cost-effective manner. In children in whom GHD is not the main factor compromising growth, supra-physiological doses of GH have been shown to increase height velocity during childhood and final height. The development of predictive models for these conditions may allow further improvements in height outcome while maintaining an acceptable safety profile. Survivors of childhood malignancy, particularly those who have had craniospinal irradiation, represent a particularly challenging group. They appear to be less responsive to GH than children with idiopathic GHD and have a tendency to enter puberty at an earlier age. Both of these factors have a negative impact on their final height. Strategies that combine GH treatment with suppression of puberty using a gonadotropin releasing hormone analog may result in improved height outcomes. When children with GHD are treated with standard doses of GH there is a strong safety record. Adverse events during GH therapy are uncommon and often not drug related. Continued surveillance into adult life is crucial however, particularly in children receiving supra-physiological doses of GH or whose underlying condition increases their risk of adverse effects.

Hypothalamic growth hormone-releasing hormone (GHRH) cell number is increased in human illness, but is not reduced in Prader-Willi syndrome or obesity

BACKGROUND

Acute illness leads to increased GH, but reduced IGF-I secretion, while both are reduced in chronic illness. Prader-Willi syndrome (PWS) is a genetic obesity syndrome, with GH deficiency a feature independent of obesity. Reduced GH secretion may result from decreased hypothalamic release of GH-releasing hormone (GHRH).

OBJECTIVE

To quantify hypothalamic GHRH neurone cell number in control subjects with various lengths of premorbid illness duration, PWS and non-PWS obese subjects.

DESIGN

We examined GHRH neurones in the infundibular nucleus/median eminence complex of control subjects (n = 26, including four children), PWS (n = 6) and non-PWS (n = 4) obese adults and PWS children (n = 2), by quantitative immunocytochemistry, using postmortem material.

RESULTS

We found: (i) higher GHRH cell number during prolonged illness prior to death in both control adults (r = +0.62, P = 0.002, cell number vs. premorbid illness duration) and PWS adults (r = +0.90, P = 0.02); (ii) higher GHRH cell number in female than male adults [by 53% (95% confidence interval 28-83%) in controls, P = 0.005, correcting for premorbid illness duration]; (iii) no difference in GHRH cell number between PWS adults and control or non-PWS obese adults (P = 0.7 and P = 0.4, adjusting for sex and illness duration); and (iv) low GHRH cell number in only one PWS child (who had been receiving exogenous GH therapy).

CONCLUSIONS

These findings suggest continued activation of GHRH neurones during prolonged illness. There is no evidence that the GH deficiency in PWS results from reduced GHRH cell number, and GHRH neuronal responses to illness and exogenous GH treatment appear normal in PWS.

Growth hormone treatment in a girl with Prader Willi syndrome

Prader Willi syndrome (PWS) is a rare endocrine-metabolic disorder that is characterised by neonatal hypotonia, hyperphagia, marked obesity, short stature, hypogonadism and behavioural problems. 7-20% percent of these children develop diabetes mellitus. A large number of individuals with PWS show growth hormone (GH) deficiency. Recent studies indicate beneficial effects of GH replacement therapy not only for their linear growth but also for correction of metabolic dysfunction. In the present communication this article details about the therapeutic outcome in a girl with PWS who received recombinant growth hormone (rGH), Genotropin. Some carry-over therapeutic benefits have been observed even after discontinuation of rGH.

Endocrine dysfunction in Prader-Willi syndrome: a review with special reference to GH

Prader-Willi syndrome is a genetic disorder occurring in 1 in 10,000-16,000 live-born infants. In the general population, approximately 60 people in every 1,000,000 are affected. The condition is characterized by short stature, low lean body mass, muscular hypotonia, mental retardation, behavioral abnormalities, dysmorphic features, and excessive appetite with progressive obesity. Furthermore, morbidity and mortality are high, probably as a result of gross obesity. Most patients have reduced GH secretory capacity and hypogonadotropic hypogonadism, suggesting hypothalamic-pituitary dysfunction. Replacement of GH and/or sex hormones may therefore be beneficial in Prader-Willi syndrome, and several clinical trials have now evaluated GH replacement therapy in affected children. Results of GH treatment have been encouraging: improved growth, increased lean body mass, and reduced fat mass. There was also some evidence of improvements in respiratory function and physical activity. The long-term benefits of GH treatment are, however, still to be established. Similarly, the role of sex hormone replacement therapy needs to be clarified as few data exist on its efficacy and potential benefits. In summary, Prader-Willi syndrome is a disabling condition associated with GH deficiency and hypogonadism. More active treatment of these endocrine disorders is likely to benefit affected individuals.

Visceral adipose tissue and metabolic complications of obesity are reduced in Prader-Willi syndrome female adults: evidence for novel influences on body fat distribution

Visceral obesity is detrimental to health, but the mechanisms controlling body fat distribution are not fully understood. In premenopausal adult females (30 nonobese, 14 obese [body mass index >30 kg/m(2)]), variance in fasting insulin, glucose, insulin/glucose ratio, C-peptide/insulin ratio, triglycerides, and high-density lipoprotein/low-density lipoprotein-cholesterol ratio, were independently influenced by visceral but not total sc or abdominal sc adipose tissue, as measured by whole-body magnetic resonance imaging. Adult females with Prader-Willi syndrome (n = 13) had significantly reduced visceral adiposity, compared with obese controls (visceral/total sc adipose tissue ratio: 0.067 +/- 0.017 vs. 0.108 +/- 0.021), independent of their total adiposity (P < 0.001), or use of exogenous sex steroids. This is in contrast to that expected by their physical inactivity, hypogonadism, adult GH deficiency, and psychiatric problems. Females with Prader-Willi syndrome not receiving sex steroids (n = 8) had significantly reduced fasting insulin, insulin/glucose ratio, and triglycerides and increased C-peptide/insulin ratio, compared with obese controls, adjusting for total (P < 0.05) but not visceral adiposity (P = 0.3-0.6), supporting their association. The cause of the reduced visceral adiposity in Prader-Willi syndrome may reflect novel hormonal, hypothalamic, and/or genetic influences on body fat distribution.

Impairment of GH responsiveness to GH-releasing hexapeptide (GHRP-6) in Prader-Willi syndrome

The aim of this study was to evaluate the GH-releasing activity of a synthetic hexapeptide, GHRP-6, in the Prader-Willi syndrome (PWS). Sixteen PWS patients (7 males and 9 females, aged 12.7-38.3 yr), 15 with essential obesity (OB) (7 males and 8 females, aged 12.9-42.9 yr), and 8 short normal children (SN; 3 males and 5 females, aged 10.2-14.3 yr) underwent 2 tests on separate occasions, being challenged with GHRP-6 (1 microg/kg, iv) or GHRH (1 microg/kg, iv)+PD (60 or 120 mg for children or adults, po). Moreover, in 11 patients with PWS and in the group of SN, the GH response to at least 2 stimulation tests had been previously determined. GH was analyzed either as mean peak values (GHp, mcg/l), or as the area under the curve (AUC, mcg/l/h) and the net incremental area under the curve (nAUC, mcg/l/h). In the group of PWS subjects, GH responses to both GHRP-6 (GHp: 11.4+/-2.0; AUC: 588+/-113; nAUC: 483+/-108) and GHRH+PD (GHp: 7.3+/-1.8; AUC: 486+/-122; nAUC: 371+/-250) were significantly lower than those observed either in OB (GHRP-6: GHp: 25.7+/-3.2, p<0.003; AUC: 1833+/-305, p<0.005; nAUC: 1640+/-263, p<0.0001. GHRH+PD: GHp: 15.1+/-2.4, p<0.009; AUC: 1249+/-248, p<0.003; nAUC: 918+/-230, p<0.006) or in SN patients (GHRP-6: GHp: 39.1+/-3.1, p<0.0001; AUC: 2792+/-158, p<0.0001; nAUC: 2705+/-165, p<0.00005. GHRH+PD: GHp: 27.5+/-3.7, p<0.0001; AUC: 1873+/-251, p<0.0001; nAUC: 1692+/-219, p<0.0005). Unlike control groups, in PWS patients GH levels after GHRP-6 did not differ from those obtained after GHRH+PD. Interestingly, low IGF-I values were present in all PWS subjects. Furthermore, no patient with PWS showed normal GH response to the previously performed GH stimulation tests. As already reported, GH release after GHRP-6 or GHRH+PD was significantly lower in OB than in SN subjects. In conclusion, our data indicate that: 1) GH response to GHRP-6 is clearly impaired in PWS; 2) the blunted GH responses to the provocative stimuli in PWS are not an artifact of obesity; 3) short stature in PWS is caused by a complex dysfunction of the hypothalamo-pituitary structures.