Effects of growth hormone on body composition and bone metabolism

Metabolic Responses to Epinephrine by Periparturient Dairy Cows Fed Prepartum Diets Differing in Predicted Metabolizable Protein Supply

We determined the effects of prepartum dietary metabolizable protein (MP) supply on lipolytic and glucose response to epinephrine stimulus during the periparturient period. Twelve non-lactating cows in second or greater pregnancies were assigned to a low MP (LMP) diet formulated to provide ~900 g/day MP or a high MP (HMP) diet to provide ~1,100 g/day MP. Cows received prepartum diets from 28 days before expected parturition to day of parturition and then received a common lactation diet until 35 days postpartum. Blood was sampled weekly to day −7, daily to day 7, and weekly through day 35 relative to parturition for analysis of glucose, non-esterified fatty acids (NEFAs), 3-hydroxybutyrate (BHB), urea N, and total protein concentrations. Epinephrine challenges were conducted on day −10 before expected parturition and days 7 and 14 postpartum. Epinephrine [1.4 μg/kg body weight (BW)] was administered via jugular vein and blood was collected from the opposite jugular vein from −45 min to +120 min relative to epinephrine administration. Plasma was analyzed for glucose and NEFA concentrations. Prepartum dry matter intake (DMI) (14.7 and 12.6 ± 1.5 kg/day for LMP and HMP, respectively), postpartum DMI (21.4 and 19.4 ± 1.3 kg/day for LMP and HMP, respectively), and 4% fat-corrected milk (FCM) (37.0 and 36.8 ± 1.5 kg/day for LMP and HMP, respectively) did not differ significantly between diets. Cows fed HMP had higher plasma concentrations of urea N prepartum than cows fed LMP (14.0 vs. 7.9 ± 0.8 mg/dl). Cows fed HMP tended to have greater prepartum concentrations of total protein in plasma than those fed LMP (7.5 vs. 7.0 ± 0.2 g/dl). The area under the curve (AUC) for NEFA response to epinephrine did not differ between diets, but differed by day relative to parturition [8,284, 29,018, and 18,219 ± 2,302 min × (μeq/l) for days −10, 7, and 14, respectively]. Maximal response of NEFA concentration to epinephrine was greater for HMP than for LMP (744 vs. 438 ± 72 μeq/l). The glucose AUC did not differ between diets or among days. Lipolytic response, but not glucose response, to epinephrine was enhanced during the early postpartum period relative to the late dry period. However, those responses were not affected by prepartum MP supply.

Bone and body composition analyses by DXA in adults with GH deficiency: effects of long-term replacement therapy

PURPOSE

The effects of growth hormone (GH) replacement on bone mass and body composition in adult with GH deficiency (AGHD) are still debated with regard to their persistence in the long term. Moreover, the impact of the gender on the response to GH is controversial. Aim of this study was to evaluate the long-term effects of rhGH replacement on bone mass and body composition in a monocentric cohort of patients with AGHD.

METHODS

Data from 118 patients with AGHD (34.8 ± 14.4 years, 43 women and 75 men) treated with rhGH for a period of at least 3 years up to a maximum of 10 were retrospectively collected. Bone mineral density (BMD) at the lumbar spine, femur, and 1/3 radius, and total and truncular body composition were evaluated by dual-energy X-ray absorption (DXA) before and during treatment. Clinical and laboratory evaluations were performed before and during the treatment period on an annual basis.

RESULTS

Lumbar spine BMD consistently increased in males, while it decreased in females after a transient improvement observed during the first 4 years of therapy. There were no significant changes in femoral and 1/3 radial BMD in either sexes. Lean mass significantly increased in both sexes, while fat mass only decreased in males.

CONCLUSIONS

In AGHD patients long-term rhGH replacement therapy induces a positive effect with regard to bone mass and body composition. A sexual dimorphism in the response to treatment is evident, with males displaying a more favorable outcome.

Diabetes and Metabolic Syndrome in Survivors of Childhood Cancer

Endocrine complications, including diabetes and metabolic syndrome, are highly prevalent in childhood cancer survivors. These metabolic derangements may contribute to survivors' risk of excess cardiovascular morbidity and premature mortality. This review summarizes existing knowledge on risk of diabetes and metabolic syndrome among childhood cancer survivors, focusing specifically on known risk factors, potential mechanisms, and screening recommendations. Early diagnosis via standardized risk-based screening can improve long-term outcomes in this population. Additional work is needed to elucidate the mechanisms underlying these metabolic complications and to inform the design of risk-reducing interventions and optimize long-term cardiometabolic health among survivors of childhood cancer.

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.

Effect of one-year growth hormone therapy on body composition and cardio-metabolic risk in Indian children with growth hormone deficiency

Growth hormone (GH) deficiency in children manifests as short stature but is also associated with metabolic disturbances. Paucity of GH is also likely to be associated with increased intima media thickness. Data on body composition (BC) and carotid intima media thickness (cIMT) in children with growth hormone deficiency (GHD) from developing countries are very scarce. Therefore, objectives of present study were to assess effect of 1 year of rhGH therapy on (i) BC and lipid profile (LP) in a cohort of Indian GHD children and (ii) effect on atherosclerotic markers - cIMT in subsample. Anthropometry, BC [% body fat (BF), % lean body mass (LBM), bone mineral content (BMC)] (DXA) and LP were measured in 49 pre-pubertal GHD-children (9.3 ± 3.1 years) at baseline and after 1 year of rhGH therapy. On subset of 20 children, cIMT of right common carotid artery was also measured. Baseline BC parameters were compared with age-gender matched healthy controls (n = 49). At baseline % BF was 23 ± 9 %, LBM was 9 ± 3 kg and BMC was 0.306 ± 0.15 kg in GHD- children; BF was comparable, while lean and bone were less than controls (p < 0.05). Post therapy, significant reduction in fat (15%), and cIMT (7%) and increase in LBM and BMC by 40% and 44%, respectively (p < 0.05) was seen. Our cohort of untreated GHD children had abnormal BC and cIMT as compared to controls. rhGH therapy for 1 year had beneficial effect on BC and cardiovascular risk factors.

Enhanced effect of zinc and calcium supplementation on bone status in growth hormone-deficient children treated with growth hormone: a pilot randomized controlled trial

Reduced bone mineral content in growth hormone-deficient children (GHD) has been reported. Calcium, zinc, and vitamin D play an important role in bone formation. Hence, the aim of this pilot randomized controlled study was to evaluate the effect of calcium, vitamin D, and zinc supplementation in prepubertal GHD children treated with GH on bone health parameters. After 1 year of treatment with GH (20 mg/m(2)/week), 31 GHD (mean age 8.7 ± 2.8 years, 18 boys) prepubertal children were randomised to receive calcium (500 mg/day) and vitamin D (60,000 IU/3 months) [Group A] or a similar supplement of calcium, vitamin D, and zinc (as per Indian Recommended Allowance) [Group B] along with GH therapy for the next 12 months. The two groups were similar in anthropometric and body composition parameters at baseline (p > 0.1). After 1 year of GH therapy, height-adjusted % gain was similar in both groups, 48 % in bone mineral content (BMC) and 45 % in bone area (BA). Height-adjusted % increase in BMC was significantly (p < 0.05) higher in the second year than in the first in both the groups. This % increase in BMC and BA was greater in Group B (51 and 36 % respectively) than in Group A (49 and 34 %), although marginally (p < 0.05). Supplementation of calcium and vitamin D along with GH therapy in GHD Indian children has the potential for enhancing bone mass accrual; this effect was further enhanced through the addition of zinc supplement.

Hormones as doping in sports

Though we may still sing today, as did Pindar in his eighth Olympian Victory Ode, "… of no contest greater than Olympia, Mother of Games, gold-wreathed Olympia…", we must sadly admit that today, besides blatant over-commercialization, there is no more ominous threat to the Olympic games than doping. Drug-use methods are steadily becoming more sophisticated and ever harder to detect, increasingly demanding the use of complex analytical procedures of biotechnology and molecular medicine. Special emphasis is thus given to anabolic androgenic steroids, recombinant growth hormone and erythropoietin as well as to gene doping, the newly developed mode of hormones abuse which, for its detection, necessitates high-tech methodology but also multidisciplinary individual measures incorporating educational and psychological methods. In this Olympic year, the present review offers an update on the current technologically advanced endocrine methods of doping while outlining the latest procedures applied-including both the successes and pitfalls of proteomics and metabolomics-to detect doping while contributing to combating this scourge.

Increase in serum pregnancy-associated plasma protein-A is correlated with increase in cardiovascular risk factors in adult patients with growth hormone deficiency

Adult Growth Hormone Deficiency (AGHD) is correlated to many adverse effects on metabolism and increased cardiovascular risk. Pregnancy-associated plasma protein-A (PAPP-A) is a protease that promotes IGF-I availability in vascular tissues in recent study, and PAPP-A levels have been proposed as an early predictor of cardiac events. The aim of our study was to compare PAPP-A levels in AGHD patients with that of healthy adult subjects to determine if there is a relationship between serum PAPP-A and glucose and lipid metabolism. Twenty AGHD patients and 20 healthy, age-matched and weight-matched persons were chosen for the study. Their weight, height, blood pressure, body mass index (BMI), body fat percentage, waist and hip circumference, and waist-hips ratio were assessed. An oral glucose tolerance test was performed and venous blood was collected from the each patient's cubital vein for biochemical analysis. Serum PAPP-A level in AGHD patients was significantly higher than that of the control group [(7.62 ± 1.62 vs. 6.54 ± 1.31) p < 0.05], and PAPP-A was positively correlated to age, BMI, waist circumference and so on. After adjusting for the waist circumference, waist-hip ratio, 2 h postprandial blood glucose, triglycerides, the serum PAPP-A in AGHD patients was positively correlated to the BMI (r = 0.728, p < 0.05) and fasting insulin (r = 0.433, p < 0.05). In a multiple step-wise regression analysis, BMI, 2 h postprandial glucose, fasting insulin, HOMA-IR were independently associated with serum PAPP-A in AGHD patients. The increase in serum PAPP-A levels is associated with abnormal glucose metabolism and increased risk of atherosclerosis in AGHD patients.

New factors controlling the balance between osteoblastogenesis and adipogenesis

The majority of conditions associated with bone loss, including aging, are accompanied by increased marrow adiposity possibly due to shifting of the balance between osteoblast and adipocyte differentiation in bone marrow stromal (skeletal) stem cells (MSC). In order to study the relationship between osteoblastogenesis and adipogenesis in bone marrow, we have characterized cellular models of multipotent MSC as well as pre-osteoblastic and pre-adipocytic cell populations. Using these models, we identified two secreted factors in the bone marrow microenviroment: secreted frizzled-related protein 1 (sFRP-1) and delta-like1 (preadipocyte factor 1) (Dlk1/Pref-1). Both exert regulatory effects on osteoblastogenesis and adipogenesis. Our studies suggest a model for lineage fate determination of MSC that is regulated through secreted factors in the bone marrow microenvironment that mediate a cross-talk between lineage committed cell populations in addition to controlling differentiation choices of multipotent MSC.

GH does not modulate the early fasting-induced release of free fatty acids in mice

Fasting results in the mobilization of adipose stores and the elevation of levels of free fatty acids (FFA). In humans, this process is driven by a release in GH. Little is known regarding the role of GH in modulating this process during early stages of fasting in the mouse. Confirmation of the role of GH in modulating FFA release in the fasting mouse is of particular importance given the frequent use of mouse models to study metabolic mechanisms. Here, we correlate the initial release of FFA throughout fasting in mice with pulsatile GH secretion. Observations illustrate the rapid release of FFA in response to food withdrawal. This does not correlate with a rise in GH secretion. Rather, we observed a striking loss in pulsatile secretion of GH throughout the first 6 h of fasting, suggesting that GH does not modulate the initial release of FFA in the mouse in response to fasting. This was confirmed in GH receptor knockout mice, in which we observed a robust fasting-induced rise in FFA. We further illustrate the dynamic relationship between the orexigenic and anorexigenic hormones ghrelin and leptin during fasting in the mouse. Our findings show an initial suppression of leptin and the eventual rise in circulating levels of acyl-ghrelin with fasting. However, altered acyl-ghrelin and leptin secretion occurs well after the rise in FFA and the suppression of GH secretion. Consequently, we conclude that although acyl-ghrelin and leptin may modulate the physiological response to drive food intake, these changes do not contribute to the initial loss of pulsatile GH secretion. Rather, it appears that the suppression of GH secretion in fasting may occur in response to an elevation in fasting levels of FFA or physiological stress. Observations highlight a divergent role for GH in modulating FFA release between man and mouse.

Cardiovascular and metabolic risk profile and acylation-stimulating protein levels in children with Prader-Willi syndrome and effects of growth hormone treatment

CONTEXT

Reports on the cardiovascular and metabolic risk profile in children with Prader-Willi syndrome (PWS) and the effects of GH treatment are scarce. Acylation-stimulating protein (ASP) stimulates glucose uptake and triglyceride storage in adipose tissue.

OBJECTIVES

The aim was to study the metabolic and cardiovascular risk profile and ASP levels and to investigate the effects of GH treatment.

DESIGN

We conducted a randomized controlled GH trial. Infants and prepubertal children were assigned to receive GH (1 mg/m(2) . d) or to serve as controls for 12 and 24 months, respectively.

PATIENTS

Eighty-five children with PWS (mean +/- sd age of 4.9 +/- 3.0 yr) participated in the study.

MAIN OUTCOME MEASURES

We measured fat percentage (fat%) with dual-energy x-ray absorptiometry, blood pressure, fasting insulin and glucose levels, serum lipids, and ASP levels.

RESULTS

Mean +/- SD fat% was 28.4 +/- 6.2 in infants and 36.9 +/- 8.5 in prepubertal children. Fat% sd score (SDS) was above 2 SDS in 95% of prepubertal children. In addition, 63% of infants and 73% of prepubertal children demonstrated at least one cardiovascular risk factor, defined as hypertension or dyslipidemia. The metabolic syndrome was demonstrated in 5% of all children. Mean +/- sd baseline ASP was 107 +/- 45 nmol/liter (normal < 58 nmol/liter) and correlated with fat mass and TG levels. GH improved fat%SDS and the HDLc/LDLc ratio (P < 0.0001 and P = 0.04). GH had no effect on mean ASP levels in this population.

CONCLUSIONS

Many children with PWS had dyslipidemia and high ASP levels. GH improved fat% and high-density lipoprotein cholesterol/low-density lipoprotein cholesterol, but not ASP. High ASP levels may prevent complete normalization of fat%SDS during GH treatment but may contribute in keeping glucose and insulin levels within normal range.

Bone mineral density and effects of growth hormone treatment in prepubertal children with Prader-Willi syndrome: a randomized controlled trial

BACKGROUND

Bone mineral density (BMD) is unknown in children with Prader-Willi syndrome (PWS), but is decreased in adults with PWS. In patients with GH deficiency, BMD increases during GH treatment.

OBJECTIVES

The aim of the study was to evaluate BMD in children with PWS and to study the effects of GH treatment.

DESIGN

We conducted a randomized controlled GH trial. Forty-six prepubertal children were randomized into either a GH-treated group (1.0 mg/m(2) . d) or a control group for 2 yr. At start, 6, 12, and 24 months of study, total body and lumbar spine BMD were measured by dual-energy x-ray absorptiometry, and lumbar spine bone mineral apparent density (BMAD) was calculated.

RESULTS

Baseline total body and lumbar spine BMD sd score (SDS) were normal [mean (sd), -0.2 SDS (1.1) and -0.4 SDS (1.2), respectively]. BMADSDS, which corrects for short stature, was also normal [mean (sd), 0.40 SDS (1.1)]. Total body BMDSDS decreased during the first 6 months of GH (P < 0.0001), but increased during the second year of treatment. After 24 months of study, total body and lumbar spine BMDSDS, and the BMADSDS did not significantly differ between GH-treated children and randomized controls (P = 0.30, P = 0.44, and P = 0.47, respectively). Results were similar when corrected for body mass index SDS. Repeated measurements analysis showed a significant positive association between IGF-I SDS and total body and lumbar spine BMDSDS, but not with BMADSDS.

CONCLUSIONS

Our results show that prepubertal children with PWS have a normal BMD. GH treatment had no effect on BMD, except for a temporary decrease of total body BMDSDS in the first 6 months.

Randomized controlled trial to investigate the effects of growth hormone treatment on scoliosis in children with Prader-Willi syndrome

CONTEXT

The prevalence of scoliosis in children with Prader-Willi syndrome (PWS) is 30-80%, depending on age. Although reports about effects of GH treatment on scoliosis in children with PWS are limited, scoliosis is generally considered a contraindication for GH treatment.

OBJECTIVE

The aim was to study the effects of GH treatment on the onset of scoliosis and curve progression in children with PWS.

DESIGN

We conducted a multicenter, randomized, controlled GH study in infants and prepubertal and pubertal children. Infants and prepubertal children were randomized into a GH-treated group (1.0 mg/m(2) . d) and a control group for 1 and 2 yr, respectively. Pubertal children were randomized to receive somatropin 1.0 or 1.5 mg/m(2) . d. Yearly, x-rays of the spine were taken, and height, weight, truncal lean body mass (with dual energy x-ray absorptiometry), and IGF-I were measured.

PATIENTS

A total of 91 children with PWS (median age, 4.7 yr; interquartile range, 2.1-7.4) participated in the study.

MAIN OUTCOME MEASURES

We measured the onset of scoliosis (Cobb >10 degrees ) and scoliotic curve progression.

RESULTS

GH-treated children had similar onset of scoliosis and curve progression as randomized controls (P = 0.27-0.79 and P = 0.18-0.98, respectively). GH treatment, IGF-I sd score (SDS), and catch-up growth had no adverse effect on the onset of scoliosis or curve progression, even after adjustment for confounders. Height SDS, truncal lean body mass, and IGF-I SDS were significantly higher in GH-treated children than in randomized controls. At baseline, a higher IGF-I SDS was associated with a lower severity of scoliosis.

CONCLUSIONS

Scoliosis should no longer be considered a contraindication for GH treatment in children with PWS.

Imprinted genes and neuroendocrine function

Imprinted genes are monoallelically expressed in a parent-of-origin dependent manner. Whilst the full functional repertoire of these genes remains obscure, they are generally highly expressed in the brain and are often involved in fundamental neural processes. Besides influencing brain neurochemistry, imprinted genes are important in the development and function of the hypothalamus and pituitary gland, key sites of neuroendocrine regulation. Moreover, imprinted genes may directly modulate hormone-dependent signalling cascades, both in the brain and elsewhere. Much of our knowledge about imprinted gene function has come from studying knockout mice and human disorders of imprinting. One such disorder is Prader-Willi syndrome, a neuroendocrine disorder characterised by hypothalamic abnormalities and aberrant feeding behaviour. Through examining the role of imprinted genes in neuroendocrine function, it may be possible to shed light on the neurobiological basis of feeding and aspects of social behaviour and underlying cognition, and to provide insights into disorders where these functions go awry.

High prevalence of central adrenal insufficiency in patients with Prader-Willi syndrome

CONTEXT

The annual death rate of Prader-Willi syndrome (PWS) patients is very high (3%). Many of these deaths are sudden and unexplained.

OBJECTIVE

Because most deaths occur during moderate infections and PWS patients suffer from various hypothalamic insufficiencies, we investigated whether PWS patients suffer from central adrenal insufficiency (CAI) during stressful conditions.

DESIGN

Overnight single-dose metyrapone tests were performed. Metyrapone (30 mg/kg) was administered at 2330 h. At 0400, 0600, and 0730 h, ACTH, 11-deoxycortisol, cortisol, and glucose levels were measured. Diurnal salivary cortisol profiles were assessed on a different day at wake-up, 30 min after wake-up, at 1400 h, and at 2000 h.

SETTING

The study was conducted in a pediatric intensive care unit.

PATIENTS

Patients included 25 randomly selected PWS patients.

MAIN OUTCOME MEASURE

Patients were considered as having CAI when ACTH levels remained below 33 pmol/liter at 0730 h.

RESULTS

Median (interquartile range) age was 9.7 (6.8-13.6) yr. Fifteen patients (60%) had an insufficient ACTH response (CAI, P < 0.001). There was no significant difference in age, gender, genotype, and body mass index SD score between patients with CAI and those without. Morning salivary cortisol levels and diurnal profiles were normal in all children, suggesting that CAI becomes apparent only during stressful conditions.

CONCLUSIONS

Strikingly, 60% of our PWS patients had CAI. The high percentage of CAI in PWS patients might explain the high rate of sudden death in these patients, particularly during infection-related stress. Based on our data, one should consider treatment with hydrocortisone during acute illness in PWS patients unless CAI has recently been ruled out with a metyrapone test.

Administration of exogenous ghrelin in obese patients with polycystic ovary syndrome: effects on plasma levels of growth hormone, glucose, and insulin

OBJECTIVE

To assess the effects of the administration of exogenous ghrelin, a peptide with potent GH-releasing activity and glucose-enhancing and insulin-lowering properties, in obese patients with polycystic ovary syndrome (PCOS).

DESIGN

Prospective, controlled study.

SETTING

Academic research environment.

PATIENT(S)

Twenty obese women with PCOS, and 15 obese controls.

INTERVENTION(S)

Oral glucose tolerance test (OGTT) and ghrelin test (1 microg/kg i.v. bolus).

MAIN OUTCOME MEASURE(S)

Basal hormonal assays, including ghrelin, were performed. Glucose, insulin, and C-peptide were assessed in a fasting condition and during the OGTT. Growth hormone, insulin, and glucose were measured basally and every 15 minutes for 90 minutes after the injection of ghrelin.

RESULT(S)

Both groups showed an insulin response to the glucose load above the normal range. Significantly lower levels of ghrelin were detected in patients with PCOS compared to controls (108.96 +/- 27.65 Fmol/mL versus 162.47 +/- 42.23 Fmol/mL). Administration of ghrelin markedly enhanced GH levels in both groups (1,888.59 +/- 1,209.53 ng/mL and 1,639.95 +/- 631.79 ng/mL per 90 minutes as GH area under the curve, respectively), with a peak occurring 30 minutes after injection. Ghrelin also induced a trend toward an increase in plasma glucose levels, and a significant decrease in insulin concentrations in both groups.

CONCLUSION(S)

The injection of ghrelin seems to override the GH secretion defect in obese women with PCOS, and to induce glucoinsulinemic changes in both controls and obese patients with PCOS.

[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.

Novel approaches to treatment of autoimmune neuroinflammation and lessons for drug development

Drug development, and especially that intended for central nervous system (CNS) disorders, still poses a challenge. We investigated both the use of bifunctional compounds designed for multiple targeting and enhanced CNS permeability, and of recombinant alpha-fetoprotein (AFP), a natural pregnancy-associated immunomodulating protein for the treatment of CNS inflammation. Bifunctional compounds showed a novel pharmacokinetic profile due to the conjugation, yet retained, and even improved pharmacodynamics. AFP was well tolerated and decreased various aspects of neuroinflammation, including disease severity, axonal loss and damage, T-cell reactivity, and antigen presentation. Our results show that both strategies may serve as future drug modalities.

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

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

Ghrelin and truncated ghrelin variant plasmid vectors administration into skeletal muscle augments long-term growth in rats

Ghrelin is an acylated peptide recently identified as an endogenous ligand for the growth hormone (GH) secretagogues (GHSs) receptor (GHS-R) and is involved in a novel system for regulating GH release. To study the biological activities of ghrelin using plasmid vector administration, we constructed myogenic expression vectors containing the full length cDNA of swine ghrelin-28 (pGEM-wt-sGhln) and truncated variant (pGEM-tmt-sGhln) consisting of the first seven residues of ghrelin (including Ser3 substituted with Trp3) with addition of a basic amino acid, Lys (K) at the C-terminus. After intramuscular injection of pGEM-wt-sGhln and pGEM-tmt-sGhln, RT-PCR analysis demonstrated that the ectopic expressions of ghrelin and its variant were observed 30 days post-injection. The level of GH increased in rat serum, and was significantly higher than that of the control group 20 days post-injection with pGEM-tmt-sGhln (P < 0.05). Administration of 150 microg of pGEM-wt-sGhln and pGEM-tmt-sGhln enhanced growth in rats over 30 days and great stimulatory responses were observed at day 10 and 20 post-injection respectively, whose body weight gains were on average 15% (P < 0.05) and 21% P < 0.033 significantly heavier than controls. These results suggested that skeletal muscle might have the potential to perform post-translational acylation for ghrelin, and short ghrelin variant might have the biological effects as wild type ghrelin.

Prospective randomised treatment with recombinant human growth hormone in cystic fibrosis

AIM

To evaluate the efficacy and safety of treatment with recombinant growth hormone (rGH) in patients with cystic fibrosis (CF).

METHODS

Twenty patients with CF (aged 10-23 years) were randomised to age and sex matched treatment and control groups. The treatment group received daily subcutaneous injections of 1 IU/kg/wk rGH for 12 months. Pulmonary function (forced expiratory volume in one second (FEV1) and airway resistance), exercise capacity measured with a bicycle ergometer, body composition (dual energy x ray absorptiometry), and weight were assessed at the beginning of the study and after 6 and 12 months.

RESULTS

rGH treatment did not improve weight and pulmonary function, but lean body mass increased significantly in the treatment group. Exercise capacity increased in the treatment group from 143 (16) W (mean (SD)) to 164 (19) W after 12 months of rGH treatment.

CONCLUSION

Treatment of CF patients with rGH for one year improved the exercise capacity significantly but not pulmonary function. The improved exercise capacity needs confirmation in a larger population before such an expensive treatment is justified.

Hypopituitarism in childhood

BACKGROUND

Childhood hypopituitarism may be present at birth or may be acquired. Early diagnosis and treatment promote the best possible outcomes.

METHODS

The anatomy, etiologies, clinical presentation, diagnostic testing strategies, and current treatments relevant to childhood hypopituitarism are reviewed.

RESULTS

Children with congenital hypopituitarism may present with life-threatening hypoglycemia, abnormal serum sodium concentrations, shock, microphallus in males, and, only later, growth failure. Causes of congenital hypopituitarism include septo-optic dysplasia, other midline syndromes, and mutations of transcription factors involved in pituitary gland development. Children with acquired hypopituitarism typically present with growth failure and may have other complaints depending on the etiology and the extent of missing pituitary hormones. Acquired hypopituitarism may result from tumors (most commonly craniopharyngioma), radiation, infection, hydrocephalus, vascular anomalies, and trauma.

CONCLUSIONS

An MRI of the head is critical in determining the etiology. Testing for pituitary hormone deficiencies is undertaken along with appropriate hormonal replacement and, in some cases, direct treatment of the cause of the hypopituitarism. All children with hypopituitarism require coordination of medical care by a pediatric endocrinologist and, when older, transition to the care of an internist endocrinologist. Referrals to a reproductive endocrinologist may be required as fertility issues arise.

Body composition, bone mass and microstructural analysis in GH-transgenic mice reveals that skeletal changes are specific to bone compartment and gender

Experimental and clinical studies suggest that high serum levels of growth hormone (GH) increase cortical but not trabecular bone. We studied body composition and bone structure in transgenic mice (MT-bGH) with systemic overexpression of GH. Body composition was examined with dual-energy X-ray absorptiometry (DXA), ashing, and chemical analysis, and the femora with DXA and micro computerized tomography. The absolute fat and bone tissue contents were significantly higher in GH transgenic mice vs controls (P < or = 0.05), but no significant difference was noted when normalizing the values to body weight. Male transgenics displayed no change in apparent (volumetric) femoral bone density, relative cortical area and trabecular bone volume fraction. Female transgenic mice demonstrated an increase in apparent femoral density and in trabecular bone volume fraction (+130%; P < or = 0.01). The mineralized tissue matrix density was decreased in male and female transgenic mice (P < or = 0.05). The results show that chronic GH excess affects trabecular bone in a gender-specific manner and that bone changes depend on the compartment investigated.

Hypothalamic obesity in humans: what do we know and what can be done?

Obesity is a common sequel to tumours of the hypothalamic region and their treatment with surgery and radiotherapy. The prevalence of hypothalamic obesity has been underestimated because it may take some years to develop, and the problem has been under-recognized by physicians. Weight gain results from damage to the ventromedial hypothalamus which leads, variously, to hyperphagia, a low metabolic rate, autonomic imbalance, growth hormone (GH) deficiency and various other problems that contribute to weight gain. However, with the exception of GH replacement, few clinical trials have evaluated significant numbers of patients and so the roles of various behavioural, dietary, pharmacological and obesity surgery approaches are controversial. Sufficient knowledge exists to identify those at high risk of hypothalamic obesity so that weight gain prevention approaches can be offered. In those who are already obese, we propose that the principal causal mechanisms in individual patients should be considered as a basis for guiding clinical management.

Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment

OBJECTIVE

To observe the chronic effects of human growth hormone (hGH) and AOD9604 (a C-terminal fragment of hGH) on body weight, energy balance, and substrate oxidation rates in obese (ob/ob) and lean C57BL/6Jmice. In vitro assays were used to confirm whether the effects of AOD9604 are mediated through the hGH receptor, and if this peptide is capable of cell proliferation via the hGH receptor.

METHOD

Obese and lean mice were treated with hGH, AOD or saline for 14 days using mini-osmotic pumps. Body weight, caloric intake, resting energy expenditure, fat oxidation, glucose oxidation, and plasma glucose, insulin and glycerol were measured before and after treatment. BaF-BO3 cells transfected with the hGH receptor were used to measure in vitro 125I-hGH receptor binding and cell proliferation.

RESULTS

Both hGH and AOD significantly reduced body weight gain in obese mice. This was associated with increased in vivo fat oxidation and increased plasma glycerol levels (an index of lipolysis). Unlike hGH, however, AOD9604 did not induce hyperglycaemia or reduce insulin secretion. AOD9604 does not compete for the hGH receptor and nor does it induce cell proliferation, unlike hGH.

CONCLUSIONS

Both hGH and its C-terminal fragment reduce body weight gain, increase fat oxidation, and stimulate lipolysis in obese mice, yet AOD9604 does not interact with the hGH receptor. Thus, the concept of hGH behaving as a pro-hormone is further confirmed. This data shows that fragments of hGH can act in a manner novel to traditional hGH-stimulated pathways.