Management of growth hormone deficiency in adults

Towards a Göttingen minipig model of adult onset growth hormone deficiency: evaluation of stereotactic electrocoagulation method

Background

Adult onset growth hormone (GH) deficiency (AGDH) is a potentially underdiagnosed condition, caused by damage to the pituitary gland. AGHD is treated with growth hormone replacement therapy. A large variety of clinical symptoms and changes in the metabolic homeostasis can be observed and quantified. New large animal models are needed for future drug development.

New method

In this study, we evaluate methods for a new large non-primate animal model of GH deficiency in post pubertal Göttingen Minipigs (minipig). Lesions in the pituitary gland were made by stereotaxic monopolar thermo-coagulation guided by magnetic resonance imaging (MRI), and pituitary function was evaluated using insulin tolerance test (ITT) with measurements of growth hormone secretion induced by hypoglycemia.

Results

Lesions were successfully applied to the pituitary gland without any damage to surrounding tissue including the hypothalamus, which was confirmed by post-operative MRI and post mortem histology. Plasma levels of GH during ITT showed no decrease in secreted levels one week after surgery compared to levels obtained before surgery.

Comparison with existing methods

Compared to other GH insufficiency models, eloquent brain tissue is spared. Furthermore, alternatively to rodent models, a large animal model would allow the use of human intended equipment to evaluate disease. Using the minipig avoids social, economical and ethical issues, compared with primates.

Conclusion

The lesions did not remove all GH production, but proof of concept is demonstrated. In addition, the ITT is presented as a safe and efficient method to diagnose GH deficiency in minipigs.

Comorbidities in patients with non-functioning pituitary adenoma: influence of long-term growth hormone replacement

BACKGROUND

Patients with hypopituitarism have an increased mortality. The aim of this study was to investigate comorbidities including cerebral infarction, type 2 diabetes mellitus (T2DM) and malignant tumors in patients with non-functioning pituitary adenomas (NFPA) with and without growth hormone replacement therapy (GHRT).

METHODS

Observational cohort study in patients with NFPA within the western region of Sweden. Subjects were identified through the National Patient Registry and followed between 1987 and 2014. Patient records were reviewed and standardized incidence ratios (SIRs) with 95% CIs for comorbidities were calculated.

RESULTS

In total, 426 patients were included, 206 with GHRT and 219 without. Median (range) follow-up time for patients with and without GHRT was 12.2 (0–24) and 8.2 (0–27) years, respectively. Mean ± s.d. BMI was 28.5 ± 4.5 and 26.5 ± 4.4 for patients with and without GHRT, respectively (P < 0.001). Incidence of cerebral infarction was increased (SIR: 1.39; 95% CI: 1.03–1.84; P = 0.032), with no difference between patients with and without GHRT. SIR for T2DM in patients not receiving GHRT was increased (1.65; 1.06–2.46; P = 0.018), whereas the incidence in patients receiving GHRT was not (0.99; 0.55–1.63; P = 0.99). The incidence of malignant tumors was not increased, either in patients with or without GHRT.

CONCLUSION

The incidence of cerebral infarction is increased in patients with NFPA irrespective of GHRT. Patients without GHRT had an increased risk of T2DM, whereas patients with GHRT had a normal incidence of T2DM, despite having higher BMI. Incidence of malignant tumors was not increased. Thus, long-term GHRT seems to be safe regarding risk of comorbidities.

Treatment of adult growth hormone deficiency with human recombinant growth hormone: an update on current evidence and critical review of advantages and pitfalls

Adult-onset growth-hormone (GH) deficiency (GHD) is a rare disorder, which most commonly results from pituitary or peripituitary tumors and their treatment, and is characterized by alterations in body composition, carbohydrate and lipid metabolism, bone mineral density, cardiovascular risk profile and quality of life, all of which may contribute to an increased morbidity and mortality. Since recombinant human GH (rhGH) became available in 1985, several studies have provided evidence of its beneficial effects, despite the potential risk of developing adverse effects, and much clinical experience has been accumulated. However, in adults, the precise therapeutic role of GH replacement therapy and the individual response to it remains highly variable and is still a matter of debate. In this article, we present a critical review of the available evidence on rhGH replacement therapy in GHD adults, emphasizing the pitfalls clinicians encounter in the diagnosis of GHD and monitoring of rhGH replacement therapy. We will cover all the relevant aspects regarding the potential usefulness of GH treatment, including the hot topic of mortality.

Predictors of Insulin-Like Growth Factor-I Responses to Growth Hormone Replacement in Young Adults with Growth Hormone Deficiency

BACKGROUND/AIMS

Physiological growth hormone (GH) secretion and insulin-like growth factor-I (IGF-I) levels are greater in young compared to older adults. We evaluated IGF-I levels and predictors of IGF-I responses in young adults on GH replacement.

DESIGN

From the KIMS database, 310 young adults (age 15-26 years) with severe GH deficiency related to childhood-onset disease and commenced on 'adult GH replacement' were identified. 'IGF-I responses' were estimated from first-year increments in IGF-I standard deviation scores (SDS) and adjusted for GH dose. Body composition was assessed by bioimpedance in 143 patients.

RESULTS

IGF-I levels increased markedly from baseline to 1 year of replacement (-3.75 ± 1.94 vs. -1.36 ± 1.86 SDS, p < 0.0001), but remained low compared to normative data despite dose titration. In multivariate models, IGF-I responses were positively associated with age [B (SE) SDS/(mg/m2); 0.52 (0.15), p = 0.0007] and BMI SDS [1.06 (0.25), p < 0.0001] and inversely associated with female gender [-4.45 (0.79), p < 0.0001] and baseline IGF-I SDS [-1.44 (0.20), p < 0.0001]. IGF-I responses were positively associated with first-year increases in lean body mass (r = 0.19, p = 0.003) and haemoglobin A1c (r = 0.15, p = 0.031).

CONCLUSIONS

Low IGF-I levels in young adults on treatment may reflect suboptimal GH replacement. Identification of predictors for IGF-I responses could lead to a more appropriate replacement strategy. Association between IGF-I responses and lean body mass suggests that maintaining age-appropriate IGF-I levels is important during therapy.

Seven years of growth hormone (GH) replacement improves quality of life in hypopituitary patients with adult-onset GH deficiency

OBJECTIVE

Few studies have determined the effects of long-term growth hormone (GH) replacement on quality of life (QoL). This study investigated the effects of 7 years of GH replacement on QoL.

DESIGN

A prospective, single-center, open-label study of 95 adults (mean age 52.8 years; 46 men) with adult-onset GH deficiency (GHD).

METHODS

QoL was measured using Quality of Life-Assessment for Growth Hormone Deficiency in Adults (QoL-AGHDA) and Psychological General Well-Being (PGWB) scores.

RESULTS

The GH dose was gradually increased from 0.13 mg/day to 0.42 mg/day. IGF-I SD score increased from -1.49 at baseline to 0.35 at study end. The GH replacement induced sustained improvements in total QoL-AGHDA and PGWB scores. GHD women had a more marked improvement in total QoL-AGHDA score than GHD men after 5 and 7 years. Most of the improvement in QoL was seen during the first year, but there was a small further improvement also after one year as measured using QoL-AGHDA. All QoL-AGHDA dimensions improved, but the improvement in memory and concentration as well as tenseness occurred later than that of other dimensions. Correlation analysis demonstrated that the patients with the lowest baseline QoL had the greatest improvement in QoL.

CONCLUSIONS

Seven years of GH replacement improved QoL with the most marked improvements in GHD women and in patients with low baseline QoL. Most, but not all, of the improvement in QoL was seen during the first year. Some QoL-AGHDA dimensions (memory and concentration, tenseness) responded at a slower rate than other dimensions.

Reviewing the safety of GH replacement therapy in adults

CONTEXT

Systematic data on safety of growth hormone (GH) replacement therapy in adult GH deficiency is lacking.

OBJECTIVE

To systematically describe safety of adult GH replacement therapy on glucose metabolism and long term safety.

DESIGN

A systematic web-based search of PubMed was performed guided by the Standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

OUTCOME

Randomised controlled trials of ≥3 months and open trials for ≥12 months with more than 50 adult patients (50 patient years, prospective and retrospective) including adverse event reporting as well as articles on mortality primarily on adult onset patients, reporting mortality ratios on GH treated patients, were included for the review.

RESULTS

Based on the defined selection criteria 94 studies were included. The short-term early placebo controlled trials did not demonstrate an increased frequency of diabetes mellitus (DM) and the long-term open studies did not consistently show an increased incidence of DM during GH replacement. The concern that long-term GH replacement might increase the risk of primary cancer, secondary neoplasia after tumour treatment and recurrence of previous tumours was not evident in the study data.

CONCLUSION

Based on available data, short- and long-term adult GH replacement in patients with severe GH deficiency and hypopituitarism is safe. However, the small number of subjects, limitation of long-term of GH treatment data and absence of an adequate control population is still a limitation for the interpretation of these data.

Adult growth hormone deficiency: current concepts

The clinical syndrome of adult growth hormone deficiency (AGHD) was widely recognized in the 1980s. In this review, we first describe the clinical features and diagnosis of AGHD and then state the effects of growth hormone (GH) therapy for these patients. The main characteristics of AGHD are abnormal body composition, dyslipidemia, insulin resistance, and an impaired quality of life (QoL) due to decreased psychological well-being. For diagnosing AGHD, the international consensus guidelines have suggested that an insulin tolerance test (ITT) is the gold standard, but in Japan, the growth hormone releasing peptide-2 (GHRP-2) test is available and is recommended as a convenient and safe GH stimulating test. The cut-off for diagnosing severe AGHD is a peak GH concentration of 9 g/L during the GHRP-2 test. Since 2006, GH therapy has been approved for Japanese patients with severe AGHD. For adults, GH replacement therapy should be initiated at a low dose (3 g/kg body weight/day), followed by individualized dose titration while monitoring patients' clinical status and serum insulin-like growth factor-I (IGF-I) concentrations. A variety of favorable effects of GH replacement have been indicated; however, it has not yet been established fully whether there is a direct effect of GH treatment on reducing mortality.

Baseline characteristics and effects of ten years of growth hormone (GH) replacement therapy in adults previously treated with pituitary irradiation

CONTEXT

Little is known of the importance of previous irradiation therapy for baseline characteristics and responsiveness to GH replacement in GH deficient (GHD) adults.

OBJECTIVE/DESIGN/PATIENTS

In this prospective, single-centre, open-label study, the effects of 10-year GH replacement were determined in 18 GHD adults that had previously received conventional external fractionated pituitary irradiation therapy (IRR group) and 18 non-irradiated GHD patients (non-IRR group). All patients had adult onset disease and complete deficiency of anterior pituitary hormones and both groups were comparable in terms of age, gender, body mass index (BMI), and waist:hip ratio.

RESULTS

At baseline, IRR patients had higher serum triglyceride (TG) and insulin levels and lower high density lipoprotein (HDL)-cholesterol (HDL-C) level than non-IRR patients (all p<0.05). The 10-year GH replacement improved body composition, bone mass and serum lipid profile without any between-group differences, except for a marginally more beneficial response in serum TG level in the IRR patients. After 10 years, there was no between-group difference in any variable after correction for a higher replacement dose of glucocorticoids in the IRR patients at study end using an analysis of covariance. During the 10-year GH replacement, 5 IRR patients suffered from vascular events (2 fatal) whereas only one non-fatal vascular event occurred in the non-IRR patients.

CONCLUSIONS

IRR patients with GHD display a more severely impaired cardiovascular risk profile at baseline, which was reversed by the 10-year GH replacement after correction for the higher glucocorticoid dose at study end. However, vascular events occurred more frequently in the IRR patients.

Epicardial fat thickness significantly decreases after short-term growth hormone (GH) replacement therapy in adults with GH deficiency

BACKGROUND AND AIM

Growth Hormone Deficiency (GHD) is characterized by increased visceral fat accumulation. Echocardiographic epicardial fat thickness is a new marker of visceral adiposity. Aim of the present study was to evaluate whether epicardial fat thickness can significantly change and therefore serve as a marker of visceral fat reduction after short-term rhGH replacement therapy in patients with adult-onset GHD.

METHODS AND RESULTS

Echocardiographic epicardial fat thickness was measured in 18 patients (10 M, 8 F, age 48 ± 11.8 yrs, BMI 29 ± 5.9 kg/m(2)) with adult-onset GHD, at baseline and after 6 and 12 months of rhGH therapy and in 18 healthy matched controls, at baseline. Echocardiographic epicardial fat thickness, conventional anthropometric and metabolic parameters, body fat percentage and quality of life were also evaluated. Epicardial fat thickness in adult GHD patients was higher than in controls (9.8 ± 2.8 vs 8 ± 3 mm, p < 0.05). Epicardial fat thickness significantly decreased after 6-months of rhGH replacement therapy (from 9.8 ± 2.8 to 7.0 ± 2.3 mm, P < 0.01, i.e. -29% from baseline). After 12 months of rhGH replacement therapy, epicardial fat thickness showed a further significant decrease (from 7.0 ± 2.3 to 5.9 ± 3.1 mm, P < 0.01, i.e. -40% from baseline). No significant changes in BMI or waist circumference after 6 or 12 months of rhGH therapy were observed.

CONCLUSIONS

Echocardiographic epicardial fat thickness may represent a valuable and easy marker of visceral fat and visceral fat changes during rhGH replacement treatment in patients with adult-onset growth hormone deficiency.

Efficacy and safety of growth hormone replacement therapy in Japanese adults with growth hormone deficiency: a post-marketing observational study

This large-scale observational study examined the long-term effectiveness and safety of growth hormone (GH) replacement therapy for adult GH deficiency (GHD) in Japanese clinical practice using the Hypopituitary Control and Complications Study database. The study included 402 GHD patients for safety analyses and a subset of 209 patients (149 adult-onset and 60 childhood-onset GHD patients) who had not previously received GH replacement therapy for the efficacy analyses. Data on clinical, metabolic, quality of life (QoL) characteristics, and all adverse events (AEs) were collected at baseline (start of GH treatment), 6 months, 1 year and 2 years. Over the observation period, there were improvements from baseline in insulin-like growth factor-I standard deviation scores (P<0.001), although the changes in metabolic parameters were minimal. QoL (Short Form-36) Z-scores significantly increased from baseline in both onset-type groups for several subscale domains (P<0.05). A total of 145 (36.1%) patients experienced ≥1 AE. Common AEs were hyperlipidaemia (2.7%) and hyperinsulinaemia (2.2%). Some patients experienced recurrent hypothalamic/pituitary tumour (events per 1000 patient-years: 2.78), new benign (0.93), malignant tumour (10.28) or other new tumour (0.93), new diabetes mellitus (7.45), and new stroke (3.71). Seven patients died during the observation period. Our safety findings are inconclusive about the associations between GH replacement and AEs, although the incidence of diabetes mellitus and cardiovascular events are similar to those reported in the Japanese general population. In conclusion, the key beneficial effects of GH replacement therapy for GHD are observed in routine clinical practice in Japan.

Recombinant human growth hormone affects the density and functionality of GABAB receptors in the male rat brain

The beneficial effects of growth hormone (GH) on memory and learning have previously been confirmed in both humans and in animal models. An important role of GABAB receptors for multiple forms of learning and memory has also been reported. In this study, we examined the effect of GH on the density and functionality of the metabotropic GABAB receptors in the rat brain. Male Sprague-Dawley rats (n = 24) divided into 3 groups were injected twice daily with recombinant human GH (0.07 or 0.7 IU/kg) for 7 days. The effects of the hormone were determined by quantitative autoradiography and by GABAB stimulated [(35)S]-GTPγS binding using the selective GABAB receptor agonist baclofen. The results demonstrate moderate but significant alterations in both receptor density and functionality in a number of brain regions. For example, a dose-dependent upregulation of GABAB receptors was found in the cingulate cortex, primary motor cortex and caudate putamen, whereas attenuation in the receptor density was encountered in, for example, the medial geniculate nucleus. Although the GH-induced effects on the GABAB receptor in brain areas associated with cognition were fairly pronounced, they were significant and we propose that the physiological responses observed after GH administration at least partly can be mediated through a mechanism involving GABAB receptors.

Nonalcoholic fatty liver disease in adult hypopituitary patients with GH deficiency and the impact of GH replacement therapy

BACKGROUND

Liver dysfunction in adult hypopituitary patients with GH deficiency (GHD) has been reported and an increased prevalence of nonalcoholic fatty liver disease (NAFLD) has been suggested.

OBJECTIVE

The objective of the present study was to elucidate the pathophysiology of the liver in adult hypopituitary patients with GHD.

PATIENTS AND METHODS

We recruited 69 consecutive Japanese adult hypopituitary patients with GHD and examined the prevalence of NAFLD by ultrasonography and nonalcoholic steatohepatitis (NASH) by liver biopsy. Patients had been given routine replacement therapy except for GH. We compared these patients with healthy age-, gender-, and BMI-matched controls. We further analyzed the effect of GH replacement therapy on liver function, inflammation and fibrotic markers, and histological changes.

RESULTS

The prevalence of NAFLD in hypopituitary patients with GHD was significantly higher than in controls (77 vs 12%, P<0.001). Of 16 patients assessed by liver biopsy, 14 (21%) patients were diagnosed with NASH. GH replacement therapy significantly reduced serum liver enzyme concentrations in the patients and improved the histological changes in the liver concomitant with reduction in fibrotic marker concentrations in patients with NASH.

CONCLUSIONS

Adult hypopituitary patients with GHD demonstrated a high NAFLD prevalence. The effect of GH replacement therapy suggests that the NAFLD is predominantly attributable to GHD.

Protein glycoengineering enabled by the versatile synthesis of aminooxy glycans and the genetically encoded aldehyde tag

Homogeneously glycosylated proteins are important targets for fundamental research and for biopharmaceutical development. The use of unnatural protein–glycan linkages bearing structural similarity to their native counterparts can accelerate the synthesis of glycoengineered proteins. Here we report an approach toward generating homogeneously glycosylated proteins that involves chemical attachment of aminooxy glycans to recombinantly produced proteins via oxime linkages. We employed the recently introduced aldehyde tag method to obtain a recombinant protein with the aldehyde-bearing formylglycine residue at a specific site. Complex aminooxy glycans were synthesized using a new route that features N-pentenoyl hydroxamates as key intermediates that can be readily elaborated chemically and enzymatically. We demonstrated the method by constructing site-specifically glycosylated variants of the human growth hormone.

Clinical characteristics of Japanese adults with growth hormone deficiency: a HypoCCS database study

The clinical characteristics of Caucasian adults with growth hormone (GH) deficiency (GHD) have been well defined. However, no large-scale clinical practice study has examined the clinical characteristics of Japanese adults with GHD. The aim of our study was to describe the clinical characteristics of Japanese adults with GHD by reviewing the records of participants who were GH-naive at the time of enrollment in the Hypopituitary Control and Complications Study (N = 349). The majority of participants (280 of 349; 80.2%) had adult-onset rather than childhood-onset GHD. Hypothalamo-pituitary tumors were the most common cause of GHD in Japanese adults (247 of 349; 70.8%); these tumors were primarily pituitary adenomas in participants with adult-onset GHD (156 of 243; 64.2%), and germ cell tumors (19 of 40; 47.5%) and craniopharyngiomas (18 of 40; 45.0%) in participants with childhood-onset GHD. Most participants (310 of 349; 88.8%) had multiple pituitary hormone deficiencies. Dyslipidemia (195 of 349; 55.9%), visual field loss (67 of 349; 19.2%), hypertension (59 of 349; 16.9%), and liver disease (54 of 349; 15.5%) were the most common pre-existing conditions in Japanese adults with GHD. Quality of life was decreased in seven of the eight short form-36 domains in participants with GHD compared with age- and sex-matched healthy Japanese individuals. Our findings confirm that the clinical characteristics of Japanese adults with GHD are similar to those of Caucasian adults with GHD. Confirmation of these clinical characteristics will enhance the ability of clinicians to identify and treat Japanese adults with GHD.

Psychiatric and neuropsychological changes in growth hormone-deficient patients after traumatic brain injury in response to growth hormone therapy

OBJECTIVE

Traumatic brain injury (TBI) has been recently recognized as a risk factor for cognitive impairment and hypopituitarism, presented most frequently with GH deficiency (GHD). GHD is associated not only with changes in body composition, but also with impaired quality of life, cognitive dysfunctions and some psychiatric sequelae, usually classified as "depression" or "atypical depression". The impact of GH therapy on mental status in TBI patients is still unknown.

DESIGN

Psychiatric and cognitive functions were tested in 6 GHD patients at baseline (minimum 3 yr after TBI), reassessed after 6 months of GH therapy as well as 12 months after discontinuation of GH therapy. Psychiatric and cognitive examinations included semi-structured interviews and 3 instruments: Symptom-checklist (SCL-90-R), Zung Depression Inventory, and standard composite neuropsychological battery.

RESULTS

Six months of GH therapy in GHD TBI patients improved cognitive abilities (particularly verbal and non-verbal memory) and significantly improved psychiatric functioning. Severity of depression decreased, as well as intensity of interpersonal sensitivity, hostility, paranoid ideation, anxiety, and psychoticism. Somatization, obsessive-compulsive symptoms and phobic anxiety decreased in all except in one patient. In 3 GHD patients who stopped GH therapy for 12 months we registered worsening of the verbal and non-verbal memory, as well symptoms in 3 SCL dimensions: inter-personal sensitivity, anxiety, and paranoid ideation.

CONCLUSION

GH-deficient TBI patients are depressed and have cognitive impairment. GH therapy induced reduction of depression, social dysfunction, and certain cognitive domains. Our preliminary data support the necessity of conducting randomized placebo-controlled trials on the effects of GH therapy on neuropsychological and psychiatric status in GHD TBI patients.

Human growth hormone expressed in tobacco cells as an arabinogalactan-protein fusion glycoprotein has a prolonged serum life

Therapeutic proteins with molecular weights lower than 40 kDa often have short serum half-lives due to their susceptibility to serum proteases and rapid renal clearance. Chemical derivatization, such as PEGylation, or expression as serum albumin fusions increases molecular mass and overcome these problems but at the expense of decreased bioactivity. Here we applied a new method that yields biologically potent recombinant human growth hormone (rhGH) with increased serum half-life when expressed as an arabinogalactan-protein (AGP) in tobacco BY-2 cells. Thus, rhGH was expressed with 10 repeats of the AGP glycomodule Ser-Hyp (SO) at the C-terminus (rhGH-(SO)(10)). We also expressed rhGH as an AGP-enhanced green fluorescent protein (EGFP) fusion, designated rhGH-(SO)(10)-EGFP, to assess the cellular distribution of the glycoprotein, which was mainly extracellular. Recombinant hGH-(SO)(10) bound the hGH receptor with an affinity similar to that of a rhGH standard, stimulated the same intracellular signaling pathway as hGH, but possessed an in vivo serum half-life more than sixfold that of the hGH control. Furthermore, rhGH-(SO)(10) gave a 500 fold greater secreted yield than the non-glycosylated control rhGH that was also targeted for secretion. Detailed analysis of the rhGH-(SO)(10) glycans indicated a conserved structure with relatively little microheterogeneity and an average size of 25 monosaccharide residues. These results were consistent with earlier work expressing interferon alpha 2b as an AGP chimera and further demonstrate the feasibility of this approach to the production of long-acting, biologically potent therapeutic proteins by plant cells.

Vasoprotective effects of life span-extending peripubertal GH replacement in Lewis dwarf rats

In humans, growth hormone deficiency (GHD) and low circulating levels of insulin-like growth factor 1 (IGF-1) significantly increase the risk for cerebrovascular disease. Genetic growth hormone (GH)/IGF-1 deficiency in Lewis dwarf rats significantly increases the incidence of late-life strokes, similar to the effects of GHD in elderly humans. Peripubertal treatment of Lewis dwarf rats with GH delays the occurrence of late-life stroke, which results in a significant extension of life span. The present study was designed to characterize the vascular effects of life span-extending peripubertal GH replacement in Lewis dwarf rats. Here, we report, based on measurements of dihydroethidium fluorescence, tissue isoprostane, GSH, and ascorbate content, that peripubertal GH/IGF-1 deficiency in Lewis dwarf rats increases vascular oxidative stress, which is prevented by GH replacement. Peripubertal GHD did not alter superoxide dismutase or catalase activities in the aorta nor the expression of Cu-Zn-SOD, Mn-SOD, and catalase in the cerebral arteries of dwarf rats. In contrast, cerebrovascular expression of glutathione peroxidase 1 was significantly decreased in dwarf vessels, and this effect was reversed by GH treatment. Peripubertal GHD significantly decreases expression of the Nrf2 target genes NQO1 and GCLC in the cerebral arteries, whereas it does not affect expression and activity of endothelial nitric oxide synthase and vascular expression of IGF-1, IGF-binding proteins, and inflammatory markers (tumor necrosis factor alpha, interluekin-6, interluekin-1β, inducible nitric oxide synthase, intercellular adhesion molecule 1, and monocyte chemotactic protein-1). In conclusion, peripubertal GH/IGF-1 deficiency confers pro-oxidative cellular effects, which likely promote an adverse functional and structural phenotype in the vasculature, and results in accelerated vascular impairments later in life.

Dose-dependent changes in body composition during growth hormone (GH) treatment in Japanese patients with adult GH deficiency: a randomized, placebo-controlled trial

OBJECTIVE

A clinical study was carried out to investigate the efficacy and safety of two doses of GH treatment on adult growth hormone deficiency (AGHD) patients in Japan. Dose-responsiveness between GH doses and changes of body composition was examined.

DESIGN

A 24-week, randomized, placebo-controlled, double-blind clinical study in 96 Japanese AGHD patients followed by a 48-week, open-label, long-term study.

RESULTS

During the double-blind study, serum insulin-like growth factor (IGF)-I SDS and lean body mass increased and total fat mass and serum total cholesterol decreased similarly in both GH treated groups. Mean changes in IGF-I SDS were 3.63+/-1.67, 1.97+/-1.27, and -0.13+/-0.55 in high-dose (HD) group (0.012 mg/kg/day), low-dose (LD) group (0.006 mg/kg/day), and placebo group, respectively. Trunk fat mass decreased significantly (p<0.001) in HD group and LD group but not in placebo group (mean changes in percent trunk fat mass were -4.6+/-2.6%, -3.0+/-2.5% and 0.2+/-2.1% in HD group, LD group and placebo group, respectively). Serum LDL-cholesterol decreased in both GH treated groups but significantly only in HD group. Statistically significant dose-responsiveness was shown among three groups (p<0.001) with regards to IGF-I SDS, trunk fat mass, total fat mass, and lean body mass. The changes in serum IGF-I SDS, body composition, total cholesterol, and LDL-cholesterol at the end of double-blind study persisted throughout the open-label study. In addition, there was no clinically relevant adverse event during the both studies.

CONCLUSIONS

GH treatment significantly improved serum levels of IGF-I and body composition in a dose-responsive manner in Japanese AGHD patients. Total cholesterol and LDL-cholesterol levels also decreased. GH treatment was safe and generally well tolerated.

Models to predict changes in serum IGF1 and body composition in response to GH replacement therapy in GH-deficient adults

OBJECTIVE

Clinical response to GH therapy in GH-deficient (GHD) adults varies widely. Good predictors of treatment response are lacking. The aim of the study was to develop mathematical models to predict changes in serum IGF1 and body composition (BC) in response to GH therapy in GHD adults.

DESIGN AND METHODS

One hundred and sixty-seven GHD patients (103 men, median age 50 years) were studied before and after 12 months of GH treatment. GH dose was tailored according to serum IGF1 concentrations. Good responders (GR) and poor responders (PR) to GH therapy were defined as patients with a response >60th and <40th percentile respectively, for changes in serum IGF1 levels (adjusted for GH cumulative dose) and in BC (lean body mass (LBM) and body fat determined using dual-energy X-ray absorptiometry). A logistic regression model was used to predict the probability of being a GR or PR.

RESULTS

In the IGF1 prediction model, men (odds ratio (OR) 5.62: 95% confidence interval 2.59-12.18) and patients with higher insulin levels (OR 1.06: 1.00-1.12) were more likely to be GR. The accuracy of the prediction model was 70%. In the BC model, men (OR 10.72: 1.36-84.18) and GHD patients with lower LBM (OR 0.82: 0.73-0.92) and greater height (OR 1.23: 1.08-1.40) at baseline were more likely to be GR. The accuracy of the prediction model was 80%.

CONCLUSION

Accurate mathematical models to predict GH responsiveness in GHD adults were developed using gender, body height, baseline LBM, and serum insulin levels as the major clinical predictors.

The role of the somatotrophic axis in neuroprotection and neuroregeneration of the addictive brain

Early studies have shown that the abuse of alcohol, central stimulants, and opiates such as heroin destroys brain cells, reducing attention span and memory. However, new research has suggested that there may be a way to regain some of the lost attention and recall. It has recently been shown that brain cells targeted for early death by continued opiate use can be salvaged by injections of synthetic human growth hormone (GH). GH is a polypeptide hormone, normally secreted by the anterior pituitary gland, which stimulates cell growth and controls body metabolism. Recombinant human GH is currently used in replacement therapy to alleviate the symptoms of adults and children with GH deficiency syndrome. The recent observation that GH can reverse morphine-induced cell damage could open the door to new ways of treating and preventing damage from the abuse of opiates in addicts and also of treating cell damage induced by alcohol and central stimulants. This article reviews current knowledge of the somatotrophic axis, including GH and insulin-like growth factor-1 (IGF-1), in the brain and also discusses the potential use of GH/IGF-1 as agents for treatment of brain pathology in addictive diseases.

Early-onset GH deficiency results in spatial memory impairment in mid-life and is prevented by GH supplementation

GH levels increase to high concentrations immediately before puberty then progressively decline with age. GH deficiency (GHD) originating in childhood is treated with GH supplementation to foster somatic development during adolescence. It is not clear if or how early GH replacement affects memory in adulthood, or whether it can prevent the cognitive deficits commonly observed in adults with childhood-onset GHD. Rats homozygous for the Dw-4 mutation (dwarf) do not exhibit the normal increase in GH at 4 weeks of age when GH levels normally rise and are used to model childhood or early-onset GHD (EOGHD). One group of these rats was injected with GH from 4 to 14 weeks of age to model GH supplementation during adolescence with GHD beginning in adulthood (adult-onset GHD; AOGHD). Another group received GH from 4 weeks throughout the lifespan to model normal lifespan GH (GH-replete). Age-matched, Dw-4 heterozygous rats (HZ) do not express the dwarf phenotype and were used as controls. At 8 and 18 months of age, spatial learning in the water maze was assessed. At 8 months of age all experimental groups were equally proficient. However, at 18 months of age, the EOGHD group had poor spatial learning compared to the AOGHD, GH-replete, and HZ groups. Our data indicate that GHD during adolescence has negative effects on learning and memory that emerge by middle-age unless prevented by GH supplementation.

Treatment of adult growth hormone deficiency: who, why and how? A review

Adult growth hormone deficiency (AGHD) is nowadays recognized as a distinct clinical entity and replacement therapy has become a standard practice. Reflecting on the accumulated evidence, questions nevertheless arise. Should all AGHD patients be treated? What dose of GH should be given and for how long? What are the real long-term benefits, in particular regarding life expectancy? if the diagnosis of severe GHD is firmly established and if there is no contra-indication (such as an active cancer or uncontrolled diabetes), it is worthwile initiating GH replacement therapy. Treatment can indeed correct the abnormal body composition, improve various adverse cardiovascular parameters and risk factors, increase muscle strength and bone mineral density and, although to a variable degree, improve the patient's quality of life and psychological well-being. Treatment should be started with very low doses to avoid side-effects related to fluid retention and should then be gradually titrated against IGF-I values, clinical response and individual tolerance.There is unfortunately no confirmed predictive factor for the overall therapeutic response in a given individual. Thus, the decision to whether or not pursue the therapy will depend on the ratio of perceived and expected benefits over cost and risks of treatment, as well as on the persistent motivation of the patient.

Diabetes mellitus in long-term survivors of childhood cancer. Increased risk associated with radiation therapy: a report for the childhood cancer survivor study

BACKGROUND

Childhood cancer survivors are at increased risk of morbidity and mortality. To further characterize this risk, this study aimed to compare the prevalence of diabetes mellitus (DM) in childhood cancer survivors and their siblings.

METHODS

Participants included 8599 survivors in the Childhood Cancer Survivor Study (CCSS), a retrospectively ascertained North American cohort of long-term survivors who were diagnosed between 1970 and 1986 as well as 2936 randomly selected siblings of the survivors. The main outcome was self-reported DM.

RESULTS

The mean ages of the survivors and the siblings were 31.5 years (age range, 17.0-54.1 years) and 33.4 years (age range, 9.6-58.4 years), respectively. Diabetes mellitus was reported in 2.5% of the survivors and 1.7% of the siblings. After adjustment for body mass index, age, sex, race/ethnicity, household income, and insurance, the survivors were 1.8 times more likely than the siblings to report DM (95% confidence interval [CI], 1.3-2.5; P < .001), with survivors who received total body irradiation (odds ratio [OR], 12.6; 95% CI, 6.2-25.3; P < .001), abdominal irradiation (OR, 3.4; 95% CI, 2.3-5.0; P < .001), and cranial irradiation (OR, 1.6; 95% CI 1.0-2.3; P = .03) at increased risk. In adjusted models, an increased risk of DM was associated with total body irradiation (OR, 7.2; 95% CI, 3.4-15.0; P < .001), abdominal irradiation (OR, 2.7; 95% CI, 1.9-3.8; P < .001), use of alkylating agents (OR, 1.7; 95% CI, 1.2-2.3; P < .01), and younger age at diagnosis (0-4 years; OR, 2.4; 95% CI, 1.3-4.6; P < .01).

CONCLUSION

Childhood cancer survivors treated with total body or abdominal irradiation have an increased risk of diabetes that appears unrelated to body mass index or physical inactivity.

Adult-onset growth hormone deficiency: causes, complications and treatment options

PURPOSE OF REVIEW

Description of the progresses related to the complications and treatment of adult-onset growth hormone deficiency.

RECENT FINDINGS

Growth hormone deficiency in adults has gained attention as a clinical syndrome associated with increased morbidity and possibly mortality. Many studies have been conducted on the consequences of growth hormone deficiency and of its replacement, supporting its use in appropriate patients. Early studies were characterized by a high incidence of side effects due to a lack of pilot data to guide appropriate dosing. Given the wide variability in individual responsiveness to growth hormone therapy based on age, sex, and body composition, recent work has been dedicated to understanding which patients derive benefit from therapy, minimizing side effects, and ensuring cost-effectiveness.

SUMMARY

Long-term prospective trials have shown that growth hormone replacement therapy results in improvements in body composition, dyslipidemia, bone mineral density, and quality of life. The effects on endpoints such as cardiovascular morbidity and mortality and fractures are, however, not fully proven. Randomized trials that compare homogenous groups of growth hormone deficiency patients are still needed. Given the high cost of treatment, dynamic testing for growth hormone deficiency should only be performed in patients in whom there is high clinical suspicion, and therapy should be limited to those with biochemically proven growth hormone deficiency.

[Growth hormone deficiency in adulthood: how to diagnose and when to treat?]

Adult growth hormone deficiency (AGHD) is a well-established clinical entity with heterogeneous characteristics, in which the main causes are hypothalamus-pituitary tumors and/or their treatment. The diagnosis of ADGH should be considered in patients with a prior history of childhood-onset GH deficiency or a history of organic hypothalamus-pituitary disease. In these patients diagnosis is performed biochemically by provocative tests of GH secretion, once the measurement of the biological markers for GH action:IGF-l and IGFBP-3 levels, can be in the normal range in an important percentage of AGHD patients. The current treatment using an initial low dose of hrGH followed by individualised dose titration adjusted according to serum IGF-1 levels, leads to similar beneficial effects with less incidence of side effects, improved tolerance to treatment and a lower stable GH dose as compared to hrGH replacement therapy based on body weight or body surface area. As some patients might not profit from hrGH therapy, the potential beneficial effects of hrGH replacement therapy should be analyzed on individualized basis. Alternative available therapies with similar efficacy should be taken into consideration. Physical activity may improve body compostion, cardiovascular perfomance and well being in ADGH subjects not submitted to hrGH treatment. An important target of hrGH replacement therapy is its impact on quality of life, leading to social and professional improvement. Epidemiological evidence points to a decreasing life expectancy in ADGH patients but data regarding the impact of hrGH replacement on life expectancy are still lacking.