Congenital growth hormone (GH) deficiency and atherosclerosis: effects of GH replacement in GH-naive adults

Brain morphometry and estimation of aging brain in subjects with congenital untreated isolated GH deficiency

PURPOSE

Individuals with isolated GH deficiency (IGHD) due to a mutation in the GHRH receptor gene have a normal life expectancy and above 50 years of age, similar total cognitive performance, with better attention and executive function than controls. Our objectives were to evaluate their brain morphometry and brain aging using MRI.

METHODS

Thirteen IGHD and 14 controls matched by age, sex, and education, were enrolled. Quantitative volumetric data and cortical thickness were obtained by automatic segmentation using Freesurfer software. The volume of each brain region was normalized by the intracranial volume. The difference between the predicted brain age estimated by MRI using a trained neuronal network, and the chronological age, was obtained. p < 0.005 was considered significant and 0.005 < p < 0.05 as a suggestive evidence of difference.

RESULTS

In IGHD, most absolute values of cortical thickness and regional brain volumes were similar to controls, but normalized volumes were greater in the white matter in the frontal pole and in the insula bilaterally, and in the gray matter, in the right insula and in left Caudate (p < 0.005 for all comparisons) We also noticed suggestive evidence of a larger volume in IGHD in left thalamus (p = 0.006), right thalamus (p = 0.025), right caudate (p = 0.046) and right putamen (p = 0.013). Predicted brain ages were similar between groups.

CONCLUSION

IGHD is primarily associated with similar absolute brain measurements, and a set of larger normalized volumes, and does not appear to alter the process of brain aging.

Common and uncommon mouse models of growth hormone deficiency

Mouse models of growth hormone deficiency (GHD) have provided important tools for uncovering the various actions of GH. Nearly 100 years of research using these mouse lines has greatly enhanced our knowledge of the GH/IGF-1 axis. Some of the shared phenotypes of the five "common" mouse models of GHD include reduced body size, delayed sexual maturation, decreased fertility, reduced muscle mass, increased adiposity, and enhanced insulin sensitivity. Since these common mouse lines outlive their normal-sized littermates - and have protection from age-associated disease - they have become important fixtures in the aging field. On the other hand, the twelve "uncommon" mouse models of GHD described herein have tremendously divergent health outcomes ranging from beneficial aging phenotypes (similar to those described for the common models) to extremely detrimental features (such as improper development of the CNS, numerous sensory organ defects, and embryonic lethality). Moreover, advancements in next generation sequencing technologies have led to the identification of an expanding array of genes that are recognized as causative agents to numerous rare syndromes with concomitant GHD. Accordingly, this review provides researchers with a comprehensive up-to-date collection of the common and uncommon mouse models of GHD that have been used to study various aspects of physiology and metabolism associated with multiple forms of GHD. For each mouse line presented, the closest comparable human syndromes are discussed providing important parallels to the clinic.

Skin assessment in congenital untreated isolated GH deficiency

PURPOSE

The separation between the inside and outside through the skin was fundamental for the evolution of prevertebrates, which grow through extrapituitary circuits, to vertebrates, which grow through the somatotrophic axis, namely pituitary growth hormone (GH). and circulating IGF1.Individuals with untreated isolated growth hormone (GH) deficiency (IGHD) due to a mutation in the GH-releasing hormone receptor (GHRH) gene, residing in Itabaianinha, Brazil, are vulnerable to skin cancer and have reduced sweating. However other aspects of their skin physiology are still unknown. Our objectives were to evaluate the number of skin cancers, skin aging, and functional aspects of the skin in this IGHD cohort.

METHODS

Twenty-six IGHD individuals and 26 controls matched by age, sex, ethnicity, and occupation were submitted to a biochemical, dermatological and a functional skin assessment by the Multi Probe Adapter Cutometer® MPA 580.

RESULTS

There was no difference in the number of skin cancers and in the degrees of photodamage between the groups. The melanin content in the forearm was similar between the groups but was lower in the buttocks (p = 0.005), as well as skin resistance (p < 0.0001) and elasticity (p = 0.003), lower in the IGHD. There was no difference in hydration and sebum content between the two groups.

CONCLUSION

IGHD is apparently associated with a neutral profile in terms of skin cancer and photodamage, with similar melanin on the forearm and lower buttocks, lower skin resistance and elasticity, with hydration and sebum similar to controls.

Childhood-Onset GH Deficiency versus Adult-Onset GH Deficiency: Relevant Differences Regarding Insulin Sensitivity

The results of the studies on the pattern of insulin sensitivity (IS) are contradictory in patients with GH deficiency (GHD); however, the interference of the GHD onset stage, childhood or adulthood in the IS has not been assessed by euglycemic hyperinsulinemic clamp (EHC), a gold-standard method for the assessment of insulin sensitivity. In a prospective cross-sectional study, we assessed IS and body composition in 17 adults with hypopituitarism without GH replacement, ten with childhood-onset (COGHD) and seven with adulthood-onset (AOGHD) and compared them to paired control groups. COGHD presented higher IS (p = 0.0395) and a similar percentage of fat mass (PFM) to AOGHD. COGHD showed higher IS than the control group (0.0235), despite a higher PFM (0.0022). No differences were found between AODGH and the control group. In AOGHD and the control group, IS was negatively correlated with PFM (rs: −0.8214, p = 0.0234 and rs: −0.3639, p < 0.0344), while this correlation was not observed with COGHD (rs: −0.1152, p = 0.7514). Despite the higher PFM, patients with COGHD were more sensitive to insulin than paired healthy individuals, while patients with AOGHD showed similar IS compared to controls. The lack of GH early in life could modify the metabolic characteristics of tissues related to the glucose metabolism, inducing beneficial effects on IS that persist into adulthood. Thus, the glycometabolic findings in patients with COGHD seems to be not applicable to AOGHD.

Metabolic Profile and Echocardiographic Evaluation in Adults with Growth Hormone Deficiency

Adult growth hormone deficiency (AGHD) is associated with increased cardiovascular risks. The primary endpoint of this retrospective cohort study was to compare metabolic profile and echocardiographic parameters in childhood-onset (CO) and adulthood-onset (AO) AGHD patients. 26 patients with CO AGHD (19 males, 26.8±8.5 years) and 41 patients with AO AGHD (23 males, 35.1±6.8 years) were included. The standard deviation score of insulin-like growth factor-1 (IGF-1 SDS), metabolic profile, liver sonography and echocardiographic parameters were compared. The IGF-1 SDS were significantly lower in CO AGHD patients (p<0.05). AO AGHD patients showed much profound glycolipid aberrations, elevated C-reactive protein levels (p=0.012), and proportionally higher prevalence of non-alcoholic fatty liver disease (95.2% vs.8.3%, p<0.001). In all subjects, IGF-1 SDS was negatively related to low-density lipoprotein cholesterol, and positively related to total cholesterol and lipoprotein a (Lpa). There were significant differences between the two group with regard to the correlations between IGF-1 SDS and high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, LPa, uric acid and creatinine (all p for interaction<0.05). CO AGHD patients exhibited smaller heart, but similar ventricular ejection fraction compared to AO AGHD patients. AGHD may be a group of heterogenous entity based on the onset ages of disease. AO patients had prominent metabolic disorders, while CO patients had smaller heart but similar cardiac performance. Whether growth hormone replacement therapy will equally benefit both CO and AO AGHD patients needs further investigations.

Growth hormone in fertility and infertility: Mechanisms of action and clinical applications

Secreted by the anterior pituitary gland, growth hormone (GH) is a peptide that plays a critical role in regulating cell growth, development, and metabolism in multiple targeted tissues. Studies have shown that GH and its functional receptor are also expressed in the female reproductive system, including the ovaries and uterus. The experimental data suggest putative roles for GH and insulin-like growth factor 1 (IGF-1, induced by GH activity) signaling in the direct control of multiple reproductive functions, including activation of primordial follicles, folliculogenesis, ovarian steroidogenesis, oocyte maturation, and embryo implantation. In addition, GH enhances granulosa cell responsiveness to gonadotropin by upregulating the expression of gonadotropin receptors (follicle-stimulating hormone receptor and luteinizing hormone receptor), indicating crosstalk between this ovarian regulator and the endocrine signaling system. Notably, natural gene mutation of GH and the age-related decline in GH levels may have a detrimental effect on female reproductive function, leading to several reproductive pathologies, such as diminished ovarian reserve, poor ovarian response during assisted reproductive technology (ART), and implantation failure. Association studies using clinical samples showed that mature GH peptide is present in human follicular fluid, and the concentration of GH in this fluid is positively correlated with oocyte quality and the subsequent embryo morphology and cleavage rate. Furthermore, the results obtained from animal experiments and human samples indicate that supplementation with GH in the in vitro culture system increases steroid hormone production, prevents cell apoptosis, and enhances oocyte maturation and embryo quality. The uterine endometrium is another GH target site, as GH promotes endometrial receptivity and pregnancy by facilitating the implantation process, and the targeted depletion of GH receptors in mice results in fewer uterine implantation sites. Although still controversial, the administration of GH during ovarian stimulation alleviates age-related decreases in ART efficiency, including the number of oocytes retrieved, fertilization rate, embryo quality, implantation rate, pregnancy rate, and live birth rate, especially in patients with poor ovarian response and recurrent implantation failure.

Vasculometabolic effects in patients with congenital growth hormone deficiency with and without GH replacement therapy during adulthood

PURPOSE

To evaluated the metabolic profiles and vascular properties in congenital growth hormone (GH) deficiency (GHD) and its replacement in adults.

PATIENTS AND METHODS

Cross-sectional study conducted in a single tertiary center for pituitary diseases. Eighty-one adult subjects were divided into three groups: (1) 29 GHD patients with daily subcutaneous GH replacement therapy (GHRT) during adulthood; (2) 20 GHD patients without GHRT during adulthood and (3) 32 controls. Only patients with adequate adherence to others pituitary hormone deficiencies were included. Anthropometric parameters, body composition by dual-energy X-ray absorptiometry, metabolic profiles and vascular properties (carotid intima media thickness, pulse wave velocity and flow-mediated dilation) were compared among the groups.

RESULTS

Waist-to-height ratio (WHR), body fat percentages and fat mass index (FMI) were lower in patients with GHRT than patients without GHRT during adulthood (0.49 ± 0.06 vs. 0.53 ± 0.06 p = 0.026, 30 ± 10 vs. 40 ± 11 p = 0.003 and 7.3 ± 4 vs. 10 ± 3.5 p = 0.041, respectively). In addition, association between longer GHRT and lower body fat percentage was observed (r =  - 0.326, p = 0.04). We found higher triglyceride (113.5 ± 62 vs. 78 ± 36, p = 0.025) and lower HDL cholesterol (51 ± 17 vs. 66 ± 23, p = 0.029) levels in patients without GHRT during adulthood in comparison to controls. No statistical differences were observed for vascular properties among the groups.

CONCLUSIONS

No differences in vascular properties were observed in congenital GHD adult patients with or without GHRT despite patients without GHRT had an unfavorable body composition. GHRT currently remains an individualized decision in adults with GHD and these findings bring new insight into the treatment and follow-up of these patients.

Disruption of the GHRH receptor and its impact on children and adults: The Itabaianinha syndrome

Since 1994, we have been studying an extended kindred with 105 subjects (over 8 generations) residing in Itabaianinha County, in the Brazilian state of Sergipe, who have severe isolated GH deficiency (IGHD) due to a homozygous inactivating mutation (c.57 + 1G > A) in the GH releasing hormone (GHRH) receptor (GHRHR) gene. Most of these individuals have never received GH replacement therapy. They have low GH, and very low and often undetectable levels of serum IGF-I. Their principal physical findings are proportionate short stature, doll facies, high-pitched-voice, central obesity, wrinkled skin, and youthful hair with delayed pigmentation, and virtual absence of graying. The newborns from this cohort are of normal size, indicating that GH is not needed for intra-uterine growth. However, these IGHD individuals exhibit a myriad of phenotypic changes throughout the body, with a greater number of beneficial than harmful consequences. This GHRH signal disruption syndrome has been a valuable model to study the GH roles in body size and function. This reviews summarized the findings we have reported on this cohort.

Clinical, Diagnostic, and Therapeutic Aspects of Growth Hormone Deficiency During the Transition Period: Review of the Literature

The role of growth hormone (GH) during childhood and adulthood is well established. Once final stature is reached, GH continues to act during the transition, the period between adolescence and adulthood in which most somatic and psychological development is obtained. The achievement of peak bone mass represents the most relevant aspect of GH action during the transition period; however, equally clear is its influence on body composition and metabolic profile and, probably, in the achievement of a complete gonadal and sexual maturation. Despite this, there are still some aspects that often make clinical practice difficult and uncertain, in particular in evaluating a possible persistence of GH deficiency once final stature has been reached. It is also essential to identify which subjects should undergo re-testing and, possibly, replacement therapy, and the definition of unambiguous criteria for therapeutic success. Moreover, even during the transition phase, the relationship between GH substitution therapy and cancer survival is of considerable interest. In view of the above, the aim of this paper is to clarify these relevant issues through a detailed analysis of the literature, with particular attention to the clinical, diagnostic and therapeutic aspects.

Association between Growth Differentiation Factor-15 and Risk of Cardiovascular Diseases in Patients with Adult Growth Hormone Deficiency

OBJECTIVE

Patients with adult growth hormone deficiency (AGHD) confer a heightened risk of cardiovascular disease and increased mortality because of metabolic disorders. Growth differentiation factor-15 (GDF-15) plays an important role in predicting metabolic abnormalities. We sought to investigate the correlation between GDF-15 and cardiovascular risk in AGHD patients.

METHODS

The study enrolled 80 AGHD patients and 80 healthy subjects. We analyzed the association between GDF-15 and some major biochemical indicators. The potential association between GDF-15 and cardiovascular disease risk was analyzed.

RESULTS

The AGHD group exhibited increased waist-hip ratio and high-sensitivity C-reactive protein (hs-CRP) and lipid levels compared with the healthy control group. Serum GDF-15 levels in AGHD group were elevated significantly compared with the control group (P < 0.001). GDF-15 levels were negatively associated with insulin-like growth factor-1 in AGHD group (P=0.006) and positively correlated with waist-to-hip ratio (P=0.018), triglycerides (P=0.007), and hs-CRP (P=0.046). In addition, GDF-15 was positively correlated with Framingham risk score significantly after adjustment for other factors (r = 0.497, P < 0.001). Moreover, GDF-15 was an independent risk factor for cardiovascular disease in AGHD patients after adjusting for traditional cardiovascular risk factors.

CONCLUSION

Elevated GDF-15 levels were significantly associated with cardiovascular risk factors and can be considered as a predictive biomarker of cardiovascular risk in AGHD patients.

Growth hormone therapy in adults with growth hormone deficiency: a critical assessment of the literature

PURPOSE

Growth hormone (GH) therapy has been studied as treatment for clinical manifestations of adult-onset growth hormone deficiency (AO-GHD), including cardiovascular risk, bone health, and quality of life. Patients with AO-GHD typically also have significant history of pituitary pathology and hypopituitarism, which raises the question of what proportion of their clinical presentation can be attributed to GHD alone. Currently, much of the existing data for GH therapy in AO-GHD come from uncontrolled retrospective studies and observational protocols. These considerations require careful reassessment of the role of GH as a therapeutic agent in adult patients with hypopituitarism.

METHODS

We contrast results from placebo-controlled trials with those from uncontrolled and retrospective studies for GH replacement in patients with hypopituitarism. We also examine the evidence for the manifestations of AO-GHD being attributed to GHD alone, as well as the data on adults with congenital, life-long untreated isolated GHD.

RESULTS

The evidence for increased morbidity and mortality in hypopituitary patients with GHD, and for the benefits of GH therapy, are conflicting. There remains the possibility that the described clinical manifestations of AO-GHD may not be due to GHD alone, but may also be related to underlying pituitary pathology, treatment history and suboptimal hormone replacement.

CONCLUSIONS

In the setting of inconsistent data on the benefits of GH therapy, treatment of AO-GHD remains an individualized decision. There is a need for more randomized, placebo-controlled studies to evaluate the long-term outcomes of GH therapy in adults with hypopituitarism.

Growth Hormone Deficiency: Health and Longevity

The important role of GH in the control of mammalian longevity was first deduced from extended longevity of mice with genetic GH deficiency (GHD) or GH resistance. Mice with isolated GHD (IGHD) due to GHRH or GHRH receptor mutations, combined deficiency of GH, prolactin, and TSH, or global deletion of GH receptors live longer than do their normal siblings. They also exhibit multiple features of delayed and/or slower aging, accompanied by extension of healthspan. The unexpected, remarkable longevity benefit of severe endocrine defects in these animals presumably represents evolutionarily conserved trade-offs among aging, growth, maturation, fecundity, and the underlying anabolic processes. Importantly, the negative association of GH signaling with longevity extends to other mammalian species, apparently including humans. Data obtained in humans with IGHD type 1B, owing to a mutation of the GHRH receptor gene, in the Itabaianinha County, Brazil, provide a unique opportunity to study the impact of severe reduction in GH signaling on age-related characteristics, health, and functionality. Individuals with IGHD are characterized by proportional short stature, doll facies, high-pitched voices, and central obesity. They have delayed puberty but are fertile and generally healthy. Moreover, these IGHD individuals are partially protected from cancer and some of the common effects of aging and can attain extreme longevity, 103 years of age in one case. We think that low, but detectable, residual GH secretion combined with life-long reduction of circulating IGF-1 and with some tissue levels of IGF-1 and/or IGF-2 preserved may account for the normal longevity and apparent extension of healthspan in these individuals.

GH Supplementation Effects on Cardiovascular Risk in GH Deficient Adult Patients: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

The current meta-analysis aims at evaluating whether the existing clinical evidence may ascertain the effects of growth hormone (GH) replacement therapy on cardiovascular risk, both in isolated GH deficiency (GHD) and in compensated panhypopituitarism including GH deficit.

METHODS

Original articles published from 1991 to 2015 were searched on Medline (Pubmed). Among an overall number of 181 potentially suitable studies, 24 fulfilled the selection criteria and were included in the analysis. Data aggregation was carried out through the calculation of the absolute risk reduction. The meta-analysis was then conducted by means of a fixed-effects model, according to the heterogeneity test (Chi-square statistic).

RESULTS

Fat-free mass (FFM) increase and fat mass (FM) reduction were found, together with a C-LDL reduction, a wide variation in glycaemia and a neutral effect on glycated haemoglobin (HbA1c) and blood pressure. These effects were valid both for isolated GHD patients and for those with compensated panhypopituitarism. The global outcome D showed a nonsignificant reduction of the overall cardiovascular risk (0.53; 95% C.I. -1.23, 2.85).

CONCLUSION

Our meta-analysis shows no signnificatly positive trend in cardiovascular risk after both short and long-term GH supplementation therapy in adult GHD patients. However, a reduction of LDL cholesterol levels has been found. No differences were found between isolated GHD participants and those affected by panhypopituitarism well compensated since at least 3 months.

Insulin growth factor-1 correlates with higher bone mineral density and lower inflammation status in obese adult subjects

PURPOSE

Obesity is a severe public health problem worldwide, leading to an insulin-resistant state in liver, adipose, and muscle tissue, representing a risk factor for type 2 diabetes mellitus, cardiovascular diseases, and cancer. We have shown that abdominal obesity is associated with homeostasis derangement, linked to several hormonal and paracrine factors. Data regarding potential link between GH/IGF1 axis, bone mineral density, and inflammation in obesity are lacking. Thus, aim of this study was to evaluate correlation among IGF-1, BMD, and inflammation in obese individuals.

METHODS

The study included 426 obese subjects, mean age 44.8 ± 14 years; BMI 34.9 ± 6.1. Exclusion criteria were chronic medical conditions, use of medications affecting bone metabolism, hormonal and nutritional status, recent weight loss, and prior bariatric surgery. Patients underwent measurements of BMD and body composition by DEXA and were evaluated for hormonal, metabolic profile, and inflammatory markers.

RESULTS

In this population, IGF-1 was inversely correlated with abdominal FM% (p < 0.001, r ² = 0.12) and directly correlated with osteocalcin (OSCA) (p < 0.002, r ² = 0.14). A negative correlation was demonstrated between IGF-1 levels and nonspecific inflammatory index, such as fibrinogen (p < 0.01, r ² = 0.04) and erythrocyte sedimentation rate (p < 0.0001, r ² = 0.03). IGF-1 was directly correlated with higher BMD, at both lumbar (p < 0.02, r ² = 0.03) and femoral site (p < 0.04, r ² = 0.03).

CONCLUSIONS

In conclusion, our results show that higher levels of serum IGF-1 in obese patients correlate with lower inflammatory pattern and better skeletal health, as demonstrated by higher BMD and osteocalcin levels. These results lead to speculate the existence of a bone-adipose-muscle interplay modulating energy homeostasis, glucose, bone metabolism, and chronic inflammation in individuals affected by abdominal obesity.

Treatment with Growth Hormone for Adults with Growth Hormone Deficiency Syndrome: Benefits and Risks

Pharmacological treatment of growth hormone deficiency (GHD) in adults began in clinical practice more than 20 years ago. Since then, a great volume of experience has been accumulated on its effects on the symptoms and biochemical alterations that characterize this hormonal deficiency. The effects on body composition, muscle mass and strength, exercise capacity, glucose and lipid profile, bone metabolism, and quality of life have been fully demonstrated. The advance of knowledge has also taken place in the biological and molecular aspects of the action of this hormone in patients who have completed longitudinal growth. In recent years, several epidemiological studies have reported interesting information about the long-term effects of GH replacement therapy in regard to the possible induction of neoplasms and the potential development of diabetes. In addition, GH hormone receptor polymorphism could potentially influence GH therapy. Long-acting GH are under development to create a more convenient GH dosing profile, while retaining the excellent safety, efficacy, and tolerability of daily GH. In this article we compile the most recent data of GH replacement therapy in adults, as well as the molecular aspects that may condition a different sensitivity to this treatment.

Growth hormone actions during development influence adult phenotype and longevity

There is considerable evidence that exposure to undernutrition, overnutrition, stress or endocrine disruptors during fetal development can increase the probability of obesity, hypertension, cardiovascular disease and other problems in adult life. In contrast to these findings, reducing early postnatal growth by altering maternal diet or number of pups in a litter can increase longevity. In hypopituitary Ames dwarf mice, which are remarkably long lived, a brief period of growth hormone therapy starting at 1 or 2weeks of age reduces longevity and normalizes ("rescues") multiple aging-related traits. Collectively, these findings indicate that nutritional and hormonal signals during development can have profound impact on the trajectory of aging. We suspect that altered "programming" of aging during development may represent one of the mechanisms of the Developmental Origins of Health and Disease (DOHaD) and the detrimental effects of "catch-up" growth.

Transcriptome profiling reveals divergent expression shifts in brown and white adipose tissue from long-lived GHRKO mice

Mice lacking the growth hormone receptor (GHRKO) exhibit improved lifespan and healthspan due to loss of growth hormone signaling. Both the distribution and activity of brown and white adipose tissue (BAT and WAT) are altered in GHRKO mice, but the contribution of each tissue to age-related phenotypes has remained unclear. We therefore used whole-genome microarrays to evaluate transcriptional differences in BAT and WAT depots between GHRKO and normal littermates at six months of age. Our findings reveal a unique BAT transcriptome as well as distinctive responses of BAT to Ghr ablation. BAT from GHRKO mice exhibited elevated expression of genes associated with mitochondria and metabolism, along with reduced expression of genes expressed by monocyte-derived cells (dendritic cells [DC] and macrophages). Largely the opposite was observed in WAT, with increased expression of DC-expressed genes and reduced expression of genes associated with metabolism, cellular respiration and the mitochondrial inner envelope. These findings demonstrate divergent response patterns of BAT and WAT to loss of GH signaling in GHRKO mice. These patterns suggest both BAT and WAT contribute in different ways to phenotypes in GHRKO mice, with Ghr ablation blunting inflammation in BAT as well as cellular metabolism and mitochondrial biogenesis in WAT.

Cardiovascular Risk in Growth Hormone Deficiency: Beneficial Effects of Growth Hormone Replacement Therapy

Growth hormone deficiency (GHD) in adulthood is associated with an increased risk of developing adverse cardiovascular events and with reduced life expectancy. Cardiovascular and metabolic abnormalities have so far been evaluated only in a small number of children with GHD and adolescents. In this article we review these abnormalities and their underlying mechanisms and discuss the beneficial effect of growth hormone treatment in subjects with GHD.

An examination of the effects of different doses of recombinant human growth hormone on children with growth hormone deficiency

The aim of the present study was to examine the effects of different doses of recombinant human growth hormone (rhGH) on children with growth hormone deficiency (GHD) and on thyroid and glucose metabolism to identify more reasonable therapeutic doses of growth hormone (GH) for the treatment of this condition. In total, 60 prepubertal patients with GHD were randomly divided into the high-dose and low-dose groups (n=30 per group). The groups were treated with 0.1 or 0.05 U/kg for 6 months, respectively. The follow-up study focused on changes to the serum levels of insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein (IGFBP)-3, blood glucose, thyroid hormone [triiodothyronine (T3) and its prohormone, thyroxine (T4), and thyroid stimulating hormone (TSH)] and the analysis of variance of the repeated data. Changes in the height, body weight and bone age of the high-dose group were greater than those of the low-dose group. After 6 months of treatment, the difference in height between the two groups was statistically significant (P<0.05). Glucose metabolism in the two groups was consistent, but there was a statistically significant difference in the fasting blood glucose (FBG) levels of the two groups after 6 months of treatment (P<0.05). Prior to treatment, the T3, T4 and TSH values (the thyroid function tests) in the two groups, especially for the value of T3 in high-dose group were varied. However, 6 months after treatment, statistically significant differences between the two groups (P<0.05) were identified. In conclusion, 0.1 U/kg of GH is beneficial to children with GHD in attaining a satisfactory height, but it leads to insulin resistance. Thus, glucose metabolism and thyroid function should be monitored on a regular basis in a clinical setting.

The somatotropic axis and aging: Benefits of endocrine defects

Reduced somatotropic [growth hormone (GH) and insulin-like growth factor-1 (IGF-1)] action has been associated with delayed and slower aging, reduced risk of frailty, reduced age-related disease and functional decline, and with remarkably extended longevity. Recent studies have added to the evidence that these relationships discovered in laboratory populations of mice apply to other mammalian species. However, the relationship of the somatotropic signaling to human aging is less striking, complex and controversial. In mice, targeted deletion of GH receptors (GHR) in the liver, muscle or adipose tissue affected multiple metabolic parameters but failed to reproduce the effects of global GHR deletion on longevity. Continued search for mechanisms of extended longevity in animals with GH deficiency or resistance focused attention on different pathways of mechanistic target of rapamycin (mTOR), energy metabolism, regulation of local IGF-1 levels and resistance to high-fat diet (HFD).

Healthspan and longevity can be extended by suppression of growth hormone signaling

Average and maximal lifespan are important biological characteristics of every species, but can be modified by mutations and by a variety of genetic, dietary, environmental, and pharmacological interventions. Mutations or disruption of genes required for biosynthesis or action of growth hormone (GH) produce remarkable extension of longevity in laboratory mice. Importantly, the long-lived GH-related mutants exhibit many symptoms of delayed and/or slower aging, including preservation of physical and cognitive functions and resistance to stress and age-related disease. These characteristics could be collectively described as "healthy aging" or extension of the healthspan. Extension of both the healthspan and lifespan in GH-deficient and GH-resistant mice appears to be due to multiple interrelated mechanisms. Some of these mechanisms have been linked to healthy aging and genetic predisposition to extended longevity in humans. Enhanced insulin sensitivity combined with reduced insulin levels, reduced adipose tissue, central nervous system inflammation, and increased levels of adiponectin represent such mechanisms. Further progress in elucidation of mechanisms that link reduced GH action to delayed and healthy aging should identify targets for lifestyle and pharmacological interventions that could benefit individuals as well as society.

Brazilian adult individuals with untreated isolated GH deficiency do not have accelerated subclinical atherosclerosis

GH and its principal mediator IGF1 have important effects on metabolic and cardiovascular (CV) status. While acquired GH deficiency (GHD) is often associated with increased CV risk, the consequences of congenital GHD are not known. We have described a large group of patients with isolated GHD (IGHD) due to a homozygous mutation (c.57+1G>A) in the GH releasing hormone receptor gene, and shown that adult GH-naïve individuals have no evidence of clinically evident premature atherosclerosis. To test whether subclinical atherosclerosis is anticipated in untreated IGHD, we performed a cross-sectional study of 25 IGHD and 27 adult controls matched for age and gender. A comprehensive clinical and biochemical panel and coronary artery calcium scores were evaluated by multi-detector tomography. Height, weight, IGF1, homeostasis model assessment of insulin resistance, creatinine and creatininekinase were lower in the IGHD group. Median and interquartile range of calcium scores distribution was similar in the two groups: IGHD 0(0) and control 0(4.9). The vast majority of the calcium scores (20 of 25 IGHD (80%) and 18 of 27 controls (66.6%)) were equal to zero (difference not significant). There was no difference in the calcium scores classification. None of IGHD subjects had minimal calcification, which were present in four controls. Three IGHD and four controls had mild calcification. There were two IGHD individuals with moderate calcification and one control with severe calcification. Our study provides evidence that subjects with congenital isolated lifetime and untreated severe IGHD do not have accelerated subclinical coronary atherosclerosis.

[Benefits and risks of growth hormone in adults with growth hormone deficiency]

Adult growth hormone (GH) deficiency is a well-recognized clinical syndrome with adverse health consequences. Many of these may improve after replacement therapy with recombinant GH. This treatment induces an increase in lean body mass and a decrease in fat mass. In long-term studies, bone mineral density increases and muscle strength improves. Health-related quality of life tends to increase after treatment with GH. Lipid profile and markers of cardiovascular risk also improve with therapy. Nevertheless, GH replacement therapy is not without risk. According to some studies, GH increases blood glucose, body mass index and waist circumference and may promote long-term development of diabetes and metabolic syndrome. Risk of neoplasia does not appear to be increased in adults treated with GH, but there are some high-risk subgroups. Methodological shortcomings and difficulties inherent to long-term studies prevent definitive conclusions about the relationship between GH and survival. Therefore, research in this field should remain active.

Monocentric study of 112 consecutive patients with childhood onset GH deficiency around and after transition

OBJECTIVES

Our aim was to analyze a large cohort of childhood onset GH deficiency (CO-GHD) adults from a unique adult center, in order to analyze their clinical management and to study the metabolic and bone status in relation to GHD and to the other pituitary deficits, and to evaluate these parameters during the long-term follow-up.

DESIGN AND METHODS

Observational retrospective cohort study on 112 consecutive CO-GHD adults transferred to our unit from 1st January 1994 to 1st March 2012. Evaluation of GHD in pediatrics and after transition was conducted following consensus guidelines. Data recorded from pediatric and adult files were GH doses, pituitary magnetic resonance imaging and function, and metabolic and bone status.

RESULTS

Most patients presented with severe CO-GHD (64%) associated with other pituitary deficits (66%). CO-GHD was acquired in 56%, congenital in 33%, and idiopathic in 11% cases. Most patients (83%) stopped GH before transfer, at 16.3 years (median), despite persistence of GHD. Median age at transfer was 19.4 years. After transfer, GHD persisted in 101 patients and four of the 11 resolutive GHD were non idiopathic. IGF1 level was <-2 SDS in 70% of treated patients at transfer and in 34% of them after 3 years of treatment. Follow-up showed improvement in lipid profile and bone mineral density in severely persistent GHD patients under GH therapy. In multivariate analysis, the associated pituitary deficits seemed stronger determinant factors of metabolic and bone status than GHD.

CONCLUSIONS

This study raises concern about discontinuation of GH replacement therapy in pediatrics in severely persistent GHD patients and about the often insufficient dose of GH in the treatment of adult patients.

Diagnosis and treatment of growth hormone deficiency in adults

The availability of synthetic recombinant human growth hormone (GH) in potentially unlimited quantities since the 1980s has improved understanding of the many nonstatural effects of GH on metabolism, body composition, physical and psychological function, as well as the consequences of GH deficiency in adult life. Adult GH deficiency is now recognized as a distinct if nonspecific syndrome with considerable adverse health consequences. GH replacement therapy in lower doses than those used in children can reverse many of these abnormalities and restore functional capacities toward or even to normal; if dosed appropriately, GH therapy has few adverse effects. Although some doubts remain about possible long-term risks of childhood GH therapy, most registries of adult GH replacement therapy, albeit limited in study size and duration, have not shown an increased incidence of cancers or of cardiovascular morbidity or mortality.

Somatotropic signaling: trade-offs between growth, reproductive development, and longevity

Growth hormone (GH) is a key determinant of postnatal growth and plays an important role in the control of metabolism and body composition. Surprisingly, deficiency in GH signaling delays aging and remarkably extends longevity in laboratory mice. In GH-deficient and GH-resistant animals, the "healthspan" is also extended with delays in cognitive decline and in the onset of age-related disease. The role of hormones homologous to insulin-like growth factor (IGF, an important mediator of GH actions) in the control of aging and lifespan is evolutionarily conserved from worms to mammals with some homologies extending to unicellular yeast. The combination of reduced GH, IGF-I, and insulin signaling likely contributes to extended longevity in GH or GH receptor-deficient organisms. Diminutive body size and reduced fecundity of GH-deficient and GH-resistant mice can be viewed as trade-offs for extended longevity. Mechanisms responsible for delayed aging of GH-related mutants include enhanced stress resistance and xenobiotic metabolism, reduced inflammation, improved insulin signaling, and various metabolic adjustments. Pathological excess of GH reduces life expectancy in men as well as in mice, and GH resistance or deficiency provides protection from major age-related diseases, including diabetes and cancer, in both species. However, there is yet no evidence of increased longevity in GH-resistant or GH-deficient humans, possibly due to non-age-related deaths. Results obtained in GH-related mutant mice provide striking examples of mutations of a single gene delaying aging, reducing age-related disease, and extending lifespan in a mammal and providing novel experimental systems for the study of mechanisms of aging.

Growth hormone and the cardiovascular system

Growth hormone (GH) exerts its effects through insulin-like growth factor-1, and although ubiquitous in human tissues, it has a significant role in cardiovascular function. In recent years, there has been a great deal of interest in GH as an etiologic factor in many cardiovascular disease states. Acromegaly, a state of endogenous GH excess, results in myocardial hypertrophy and decreased cardiac performance with increased cardiovascular mortality. Additional insight into the role of excess GH on the cardiovascular system has been gained from data collected in athletes doping with GH. Likewise, GH deficiency is associated with increased mortality, possibly from the associated increase in atherosclerosis, lipid abnormalities, and endothelial dysfunction. However, further research is required to clarify the benefit of GH treatment in both deficient states and in heart failure patients.

Arrest of atherosclerosis progression after interruption of GH replacement in adults with congenital isolated GH deficiency

OBJECTIVE

GH replacement therapy (GHRT) in adult-onset GH deficiency (AOGHD) reduces carotid intima-media thickness (IMT) and increases myocardial mass, with improvement of systolic and diastolic function. These observations have reinforced the use of GHRT on AOGHD. Conversely, we have previously reported that in adults with lifetime congenital and severe isolated GH deficiency (IGHD) due to a mutation in GHRH receptor gene (GHRHR), a 6-month treatment with depot GH increased carotid IMT, caused the development of atherosclerotic plaques, and an increase in left ventricular mass index (LVMI), posterior wall, and septal thickness and ejection fraction. Such effects persisted 12 months after treatment (12-month washout - 12 mo).

METHODS

We have studied the cardiovascular status (by echocardiography and carotid ultrasonography) of these subjects 60 months after completion of therapy (60-month washout - 60 mo).

RESULTS

Carotid IMT reduced significantly from 12 to 60 mo, returning to baseline (pre-therapy) value. The number of individuals with plaques was similar at 12 and 60 mo, remaining higher than pre-therapy. LVMI, relative posterior wall thickness, and septum thickness did not change between 12 and 60 mo, but absolute posterior wall increased from 12 to 60 mo. Systolic function, evaluated by ejection fraction and shortening fraction, was reduced at 60 mo in comparison with 12 mo returning to baseline levels. The E/A wave ratio (expression of diastolic function) decreased at 60 mo compared with both 12 mo and baseline.

CONCLUSIONS

In adults with lifetime congenital IGHD, the increase in carotid IMT elicited by GHRT was transitory and returned to baseline 5 years after therapy discontinuation. Despite this, the number of subjects with plaques remained stable at 60 mo and higher than at baseline.

Growth factors, nutrient signaling, and cardiovascular aging

Growth factors regulated by specific macronutrients have been shown to promote aging and accelerate mortality in the majority of the organisms studied. In particular, the enzymes activated by growth hormone, insulin, and insulin-like growth factor-1 in mammals and their orthologs in simple model organisms represent perhaps the best-understood proteins involved in the aging process. Dietary restriction, which reduces the level of insulin-like growth factor-1 and of other growth factors, has been associated with protection from diabetes, cancer, and cardiovascular diseases, and deficiencies in growth hormone signaling and insulin-like growth factor-1 are strongly associated with protection from cancer and diabetes in both mice and humans; however, their role in cardiac function and cardiovascular diseases is controversial. Here, we review the link between growth factors, cardiac function, and heart disease with focus on the cardioprotective and sensitizing effect of growth factors in both model organisms and humans.

Effects of depot growth hormone replacement on thyroid function and volume in adults with congenital isolated growth hormone deficiency

BACKGROUND

Conflicting data exist on the effects of GH replacement therapy (GHRT) on thyroid function and thyroid volume (TV) in GH-deficient (GHD) patients.

AIM

The aim of this study was to assess the effects of GHRT on thyroid function and TV in adults with congenital lifetime isolated GHD (IGHD).

SUBJECTS AND METHODS

We studied 20 GH-naïve adults with IGHD due to a homozygous mutation of the GHRH-receptor gene at baseline, after 6-month depot- GH replacement therapy (pGH), and 6-month washout (6mo). Total T(3), free T(4) (FT(4)), reverse T(3) (rT(3)), TSH, IGF-I, SHBG, and TV were measured; body surface area-corrected TV (CTV) was calculated.

RESULTS

IGF-I and T(3) increased pGH. T(3) levels remained elevated at 6mo. GHRT did not significantly change FT(4), rT(3), TSH, and SHBG. TV and CTV increased pGH and remained elevated at 6mo.

CONCLUSIONS

GHRT in IGHD adults caused an increase in serum T(3) levels and TV, suggesting an important role of the GH-IGF-I axis in thyroid function.

Healthy aging: is smaller better? - a mini-review

A recent report of virtually complete protection from diabetes and cancer in a population of people with hereditary dwarfism revived interest in elucidating the relationships between growth, adult body size, age-related disease and longevity. In many species, smaller individuals outlive those that are larger and a similar relationship was shown in studies of various human populations. Adult body size is strongly dependent on the actions of growth hormone (GH) and the absence of GH or GH receptor in mice leads to a remarkable extension of longevity. Many mechanisms that may account for, or contribute to, this association have been identified. It is suggested that modest modifications of the diet at different ages may extend human healthspan and lifespan by reducing levels of hormones that stimulate growth.

Single-gene mutations and healthy ageing in mammals

Studies of the effects of single-gene mutations on longevity in Caenorhabditis elegans, Drosophila melanogaster and Mus musculus identified homologous, highly conserved signalling pathways that influence ageing. In each of these very distantly related species, single mutations which lead-directly or indirectly-to reduced insulin, insulin-like growth factor (IGF) or insulin/IGF-like signalling (IIS) can produce significant increases in both average and maximal lifespan. In mice, most of the life-extending mutations described to date reduce somatotropic (growth hormone (GH) and IGF-1) signalling. The reported extensions of longevity are most robust in GH-deficient and GH-resistant mice, while suppression of somatotropic signalling 'downstream' of the GH receptor produces effects that are generally smaller and often limited to female animals. This could be due to GH influencing ageing by both IGF-1-mediated and IGF-1-independent mechanisms. In mutants that have been examined in some detail, increased longevity is associated with various indices of delayed ageing and extended 'healthspan'. The mechanisms that probably underlie the extension of both lifespan and healthspan of these animals include increased stress resistance, improved antioxidant defences, alterations in insulin signalling (e.g. hypoinsulinaemia combined with improved insulin sensitivity in some mutants and insulin resistance in others), a shift from pro- to anti-inflammatory profile of circulating adipokines, reduced mammalian target of rapamycin-mediated translation and altered mitochondrial function including greater utilization of lipids when compared with carbohydrates.

Growth hormone status predicts left ventricular mass in patients after cure of acromegaly

CONTEXT

Growth hormone excess and growth hormone deficiency (GHD) are both associated with increased cardiovascular morbidity. A specific acromegaly-related cardiomyopathy has been described, characterized in part by increased left ventricular mass (LVM). Growth hormone deficiency is associated with reduced LVM. Following cure of acromegaly with surgery or radiation therapy, GHD may develop; however, its effects on cardiac morphology and function in this population are not established.

OBJECTIVE

We hypothesized that the development of GHD in patients with prior acromegaly would be associated with cardiac morphologic and functional changes that differ from those in patients who are GH sufficient following cure of acromegaly.

DESIGN

A cross-sectional study was conducted in a Clinical Research Center. Study participants consisted of three groups of subjects (n=34): I. Cured acromegaly with GHD (n=15), II. Cured acromegaly with GH sufficiency (n=8), and III. Active acromegaly (n=11). Main outcome measures included cardiac morphology and function, using echocardiography parameters.

RESULTS

Mean age and BMI, 44.6 ± 2.3 years (SEM) and 30.7 ± 1.3 kg/m², respectively, were not different among the three groups. Mean peak GH values were: I. 2.8 ± 0.4 ng/ml; II. 30.1 ± 9.1 ng/ml (p=0.0002.) In group I, left ventricular mass, indexed to body surface area (LVMi), was within the normal range in all patients; moreover, left ventricular (LV) geometry was normal. At least 50% of patients in groups II and III had elevated LVMi, and in 50% of patients, LV geometry was abnormal, indicating pathologic hypertrophy. Ejection fraction was similar between all three groups. There were no significant differences in diastolic function.

CONCLUSIONS

Patients who develop GHD following cure of acromegaly do not demonstrate elevated LV mass, in contrast to patients with a history of acromegaly but normal GH levels or to patients with active acromegaly. This suggests that GH status after treatment of acromegaly correlates with LV mass, and that, in GH sufficient patients, reversal of remodeling may be slower than previously thought. These data suggest that it will be important to determine whether GH replacement alters left ventricular morphology over time.

Growth hormone, insulin and aging: the benefits of endocrine defects

Longevity of mice can be increased by spontaneous or experimentally induced mutations that interfere with the biosynthesis or actions of growth hormone (GH), insulin-like growth factor 1 (IGF-1), or insulin in the adipose tissue. The effects of GH resistance and deficiency of GH (along with thyrotropin and prolactin) on aging and lifespan are the most pronounced and best established of these mutations. Potential mechanisms linking these endocrine deficits with delayed aging and extended longevity include increased stress resistance, alterations in insulin and mammalian target of rapamycin (mTOR) signaling and metabolic adjustments. Physiological relationships deduced from the extreme phenotypes of long-lived mouse mutants appear to apply broadly, encompassing genetically normal ("wild-type") mice and other mammalian species. The role of GH in the control of human aging continues to be hotly debated, but recent data indicate that reduced somatotropic signaling provides protection from cancer and other age-related diseases and may promote old age survival.

Extending healthy life span--from yeast to humans

When the food intake of organisms such as yeast and rodents is reduced (dietary restriction), they live longer than organisms fed a normal diet. A similar effect is seen when the activity of nutrient-sensing pathways is reduced by mutations or chemical inhibitors. In rodents, both dietary restriction and decreased nutrient-sensing pathway activity can lower the incidence of age-related loss of function and disease, including tumors and neurodegeneration. Dietary restriction also increases life span and protects against diabetes, cancer, and cardiovascular disease in rhesus monkeys, and in humans it causes changes that protect against these age-related pathologies. Tumors and diabetes are also uncommon in humans with mutations in the growth hormone receptor, and natural genetic variants in nutrient-sensing pathways are associated with increased human life span. Dietary restriction and reduced activity of nutrient-sensing pathways may thus slow aging by similar mechanisms, which have been conserved during evolution. We discuss these findings and their potential application to prevention of age-related disease and promotion of healthy aging in humans, and the challenge of possible negative side effects.

Adipokine profile and urinary albumin excretion in isolated growth hormone deficiency

BACKGROUND

GH deficiency (GHD) is often associated with cardiovascular risk factors, including abdominal fat accumulation, hypercholesterolemia, and increased C-reactive protein. Despite the presence of these risk factors, adults with congenital lifetime isolated GHD (IGHD) due to an inactivating mutation in the GHRH receptor gene do not have premature atherosclerosis.

OBJECTIVE

The aim was to study the serum levels of adiponectin and leptin (antiatherogenic and atherogenic adipokine, respectively), and the urinary albumin excretion (UAE) in these IGHD individuals.

DESIGN AND PATIENTS

We conducted a cross-sectional study of 20 IGHD individuals (seven males; age, 50.8 +/- 14.6 yr) and 22 control subjects (eight males; age, 49.9 +/- 11.5 yr).

MAIN OUTCOME MEASURES

Anthropometric factors, body composition, blood pressure, serum adiponectin, leptin, and UAE were measured.

RESULTS

Adiponectin was higher [12.8 (7.1) vs. 9.7 (5) ng/ml; P = 0.041] in IGHD subjects, whereas no difference was observed in leptin [7.3 (6.3) vs. 9.3 (18.7 ng/ml] and UAE [8.6 (13.8) vs. 8.5 (11.1) microg/min].

CONCLUSIONS

Subjects with lifetime untreated IGHD have an adipokine profile with high adiponectin and normal leptin levels that may delay vascular damage and lesions of the renal endothelium.

Investigation of early atherosclerotic changes in acromegalic patients

BACKGROUND

Functional and morphological changes of endothelium were risk factors for mortality attributed to atherosclerosis. Studies investigating early atherosclerotic alterations and the effect of the treatment of acromegaly on these alterations gave conflicting results.

OBJECTIVE

Surrogate markers of early atherosclerotic changes, i.e. brachial artery flow-mediated dilation (FMD) and carotid artery intima-media-thickness (IMT) in active and inactive acromegalic patients were compared with control subjects matched to patients for age, sex and cardiovascular risk factors to find out the direct effects of growth hormone (GH)/insulin-like growth factor-1 excess.

METHODS

In 14 active acromegalics and their 14 matched controls, 14 inactive acromegalics and their 14 matched controls, carotid artery IMT and FMD of brachial artery were measured. Inactive acromegalics were in remission for at least 1 year.

RESULTS

Active acromegalics had higher IMT than matched controls and inactive acromegalics (0.85 +/- 0.20 mm, 0.64 +/- 1.77 mm, 0.66 +/- 0.20 mm respectively; p < 0.005, p < 0.05) and IMT of inactive acromegalics was not different from their matched controls (0.61 +/- 0.12 mm). FMD was significantly lower in active acromegalics than in matched controls and inactive acromegalics (2.910 +/- 2.00 mm, 6.5 +/- 2.81 mm, 5.68 +/- 2.9 mm respectively; p < 0.005, p < 0.05). FMD of inactive acromegalics was not significantly different from their matched controls (7.96 +/- 3.12 mm). A significant inverse relationship was found between GH and FMD in active acromegalics (r = -0.659, p = 0.010).

CONCLUSION

In active acromegalics, early atherosclerotic changes are not only attributed to the high prevalence of risk factors, but also to the abnormal GH secretion itself.

Quality of life in congenital, untreated, lifetime isolated growth hormone deficiency

Impaired quality of life (QoL) is commonly described as being associated with growth hormone (GH) deficiency (GHD), and beneficial effects of GH replacement therapy on QoL have been reported. However, most studies examined heterogeneous cohorts of patients GHD of varying etiologies, severities and age of onset. Most of these patients miss other pituitary hormones, whose replacement can also influence QoL. We studied the QoL of a homogeneous cohort of 20 adults with isolated GH deficiency (IGHD) due to the same mutation in the GH-releasing hormone receptor gene (IGHD, 10 men) using the Life Satisfaction Hypopituitarism Module (QLS-H), and compared them with 20 matched controls residing in the same community (CO, 10 men). Additionally, the IGHD group was evaluated after 6 months of treatment with bi-monthly depot GH, and after 12 months from its interruption. There was no difference in the total score of QoL (TSQoL) or in any of the nine categories that composes the questionnaire between IGHD and CO. Similar results were obtained when data were analyzed by sex. GH treatment only increased satisfaction with physical endurance, but did not cause an increase in the TSQoL. We conclude that in this unique population congenital, untreated, lifetime IGHD does not reduce QoL, and treatment with GH for 6 months only causes improvement in satisfaction with physical resistance.

The somatotropic axis and aging: mechanisms and persistent questions about practical implications

Reduced somatotropic (GH/IGF-1) signaling delays aging and extends longevity in laboratory mice. However, it is unclear whether the physiological decrease of GH and IGF-1 levels with age represents a symptom of declining neuroendocrine function, a cause of age-related alterations in body composition and functionality or a protective mechanism against age-associated disease. Although available clinical evidence does not support the use of recombinant GH as an anti-aging therapy, many studies suggest the potential utility of GH and GH secretagogues in the treatment of sarcopenia and frailty.

Pereira F, Oliveira CRP, Pereira RMC, Farias CT, Vicente TAR, Salvatori R. Consequences of lifetime isolated growth hormone (GH) deficiency and effects of short-term GH treatment on bone in adults with a mutation in the GHRH-receptor gene

OBJECTIVE

Growth hormone (GH) influences bone mass maintenance. However, the consequences of lifetime isolated GH deficiency (IGHD) on bone are not well established. We assessed the bone status and the effect of 6 months of GH replacement in GH-naive adults with IGHD due to a homozygous mutation of the GH-releasing hormone (GHRH)-receptor gene (GHRHR).

PATIENTS AND METHODS

We studied 20 individuals (10 men) with IGHD at baseline, after 6 months of depot GH treatment, and 6 and 12 months after discontinuation of GH. Quantitative ultrasound (QUS) of the heel was performed and serum osteocalcin (OC) and C-terminal cross-linking telopeptide of type I collagen (ICTP) were measured. QUS was also performed at baseline and 12 months later in a group of 20 normal control individuals (CO), who did not receive GH treatment.

RESULTS

At baseline, the IGHD group had a lower T-score on QUS than CO (-1.15 +/- 0.9 vs.-0.07 +/- 0.9, P < 0.001). GH treatment improved this parameter, with improvement persisting for 12 months post-treatment (T-score for IGHD = -0.59 +/- 0.9, P < 0.05). GH also caused an increase in serum OC (baseline vs. pGH, P < 0.001) and ICTP (baseline vs. pGH, P < 0.01). The increase in OC was more marked during treatment and its reduction was slower after GH discontinuation than in ICTP.

CONCLUSIONS

These data suggest that lifetime severe IGHD is associated with significant reduction in QUS parameters, which are partially reversed by short-term depot GH treatment. The treatment induces a biochemical pattern of bone anabolism that persists for at least 6 months after treatment discontinuation.

[News options and preparations in growth hormone therapy]

In the last twenty years, recombinant human Growth hormone (hrGH) has been available for the treatment of Growth Hormone Deficiency (GHD) in children and more recently in adults. However, the necessity of daily injections compromises the patient's compliance. Attempts to improve this compliance includes the use of pens and needle free devices, once the infusion pumps, not always physiologic, are of restricted use. When growth is the purpose of treatment, daily subcutaneous hrGH is still the most indicated. Nevertheless the expansion of GH replacement to new uses and especially in adults will need new preparations. Nowadays, the oral secretagogues have not proved efficacy to be used in clinical practice and the slow- release preparations of GH and GH releasing hormone that could improve the patient's compliance will need to be studied considering long term efficacy and safety.

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.