The influence of growth hormone status on physical impairments, functional limitations, and health-related quality of life in adults

Efficacy, safety, and patient satisfaction of norditropin and sogroya in patients with growth hormone deficiency: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Growth hormone deficiency occurs when the pituitary gland does not produce enough growth hormone. Norditropin®, a recombinant human growth hormone, and Sogroya®, an albumin-binding growth hormone derivative, are prescribed for patients with growth hormone deficiency. This systematic review assesses the efficacy, safety, and patient satisfaction associated with Norditropin and Sogroya.

METHODS

We systematically searched PubMed, Web of Science, and Scopus databases to identify eligible comparative studies. All studies published until June 2023 were included in our analysis. Our outcomes for children included height velocity and height velocity standard deviation score. In contrast, adult outcomes included adverse events, insulin-like growth factor 1-standard deviation score (IGF-1 SDS), and the Treatment Satisfaction Questionnaire for Medication-9 (TSQM-9). Results are reported as odds ratio (OR) and mean difference (MD) with a 95% confidence interval (95% CI).

RESULTS

Ten studies involving 1058 participants (665 children and 393 adults) were included in the meta-analysis. In children, Norditropin at doses of 0.034 and 0.067 mg/kg/day was compared to Sogroya at doses of 0.04, 0.08, 0.16, and 0.24 mg/kg/week. The results showed that 0.034 mg/kg/day Norditropin had a favorable impact on height velocity (MD -2.01, 95% CI -3.7 to -2.12, p < 0.00001) and height velocity standard deviation score (Mean Difference -3.61, 95% CI -5.06 to -2.16, p < 0.00001) when compared to Sogroya 0.04 mg/kg/day. Other doses showed comparable results. In adults, the only significant side effect noted was rash, which favored Sogroya (OR 0.1, 95% CI 0.04-0.27, p < 0.00001). Additionally, IGF-1 SDS was significantly higher in the Sogroya group than in the Norditropin group (MD 0.25, 95% CI 0.02-0.48, p = 0.03). Furthermore, the overall score of the TSQM-9 questionnaire, which includes three domains: convenience, effectiveness, and satisfaction, was significantly higher in the Sogroya group compared to the Norditropin group (OR 6.36, 95% CI 3.92-8.8, p < 0.00001).

CONCLUSION

Norditropin and Sogroya showed comparable efficacy and safety profiles, except for the prevalence of rash in the Norditropin group, and Sogroya has higher satisfaction among adults. More high-quality studies with more patients are required to confirm these results.

Mild traumatic brain injury as a cause of adult growth hormone deficiency: Diagnosis and treatment

In recent years, mild traumatic brain injury (mTBI) has been recognized as a cause of acquired growth hormone deficiency (AGHD) and is likely much more prevalent than previous estimates. There is great overlap between persistent symptoms following mTBI and those of AGHD and it is possible that these persistent symptoms of mTBI are, at least in part, due to or aggravated by AGHD. This article reviews the current literature of AGHD following mTBI, and proposes practice recommendations for the screening, diagnosis, and management of patients with AGHD following mTBI.

The influence of growth hormone deficiency on bone health and metabolisms

Growth hormone (GH) is a key peptide hormone in the regulation of bone metabolism, through its systemic and paracrine action mediated directly as well as by insulin-like growth factor-1 (IGF-1). Growth hormone exerts pleiotropic effects leading to an increase in linear bone growth, accumulation of bone mineral content and preservation of peak bone mass. Furthermore, it influences protein, lipid, and carbohydrate metabolism.Growth hormone deficiency (GHD) causes a low bone turnover rate leading to reduced bone mineral density (BMD) and increased bone fragility. The results of GH insufficiency are the most pronounced among children as it negatively affects longitudinal bone growth, causing short stature and in adolescents, in whom it hinders the acquisition of peak bone mass. Most studies show that treatment with recombinant human growth hormone (rhGH) in GHD patients could improve BMD and decrease fracture risk. This review aims to summarize the pathophysiology, clinical picture and management of bone complications observed in GHD.

Association Between the Growth Hormone/Insulin-Like Growth Factor-1 Axis and Muscle Density in Children and Adolescents of Short Stature

OBJECTIVE

To evaluate the association between the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis and muscle density in children and adolescents of short stature.

METHODS

Participants were children and adolescents of short stature hospitalized in the Affiliated Hospital of Jining Medical University between January 2020 and June 2021. All participants had CT scan images available. We performed an analysis of the images to calculate the muscle density or skeletal muscle attenuation (SMA), skeletal muscle index (SMI), and fat mass index (FMI). Bioelectrical impedance analysis (BIA) was used to ensure that chest CT is a credible way of evaluating body composition.

RESULTS

A total of 297 subjects were included with the mean age of 10.00 ± 3.42 years, mean height standard deviation score (SDS) of -2.51 ± 0.53, and mean IGF-1 SDS of -0.60 ± 1.07. The areas of muscle and fat tissues at the fourth thoracic vertebra level in the CT images showed strong correlation with the total weights of the participants (R²  = 0.884 and 0.897, respectively). The peak of GH was negatively associated with FMI (r = - 0.323, P <.01) and IGF-1 SDS was positively associated with SMI (r = 0.303, P <.01). Both the peak GH and IGF-1 SDS were positively associated with SMA (r = 0.244, P <.01 and r = 0.165, P <.05, respectively). Multiple stepwise linear regression analysis demonstrated that the GH peak was the predictor of FMI (β = - 0.210, P < .01), the IGF-1 SDS was the predictor of SMI (β = 0.224, P < .01), and both the peak GH and IGF-1 SDS were predictors of SMA (β = 0.180, P < .01 and β = 0.222, P < .01).

CONCLUSIONS

A chest CT scan is a credible method of evaluating body composition in children and adolescents of short stature. In these patients, peak GH and IGF-1 SDS are independent predictors of muscle density and the GF/IGF-1 axis may regulate body composition through complex mechanisms.

Growth hormone deficiency in adults with hypopituitarism-What are the risks and can they be eliminated by therapy?

Growth hormone (GH) deficiency develops early in patients with hypothalamic-pituitary disorders and is therefore common among these patients. GH deficiency in adults is associated with increased morbidity, increased body fat mass, abdominal obesity, dyslipidaemia, reduced exercise capacity, impaired cardiac function as well as reduced self-reported well-being and impaired quality of life. Since recombinant human GH became available as replacement therapy more than 25 years ago, randomised controlled trials and long-term studies, together with meta-analyses, have shown improved outcomes in adult patients with hypopituitarism receiving GH. Many of the features associated with GH deficiency in adults improve, or even normalize, and the safety profile is reassuring. The increased interest in GH deficiency in adults with hypothalamic-pituitary disorders has also contributed to the identification of other factors of importance for an outcome such as the replacement of other pituitary hormone deficiencies, and the management of the underlying hypothalamic-pituitary disease, most commonly a pituitary tumour. In this narrative review, we summarize the burden of GH deficiency in adults with hypopituitarism, the impact of GH replacement on the outcome, as well as safety. Based on currently available data, GH replacement should be considered routine management of adults with hypopituitarism.

Safety and effectiveness of Omnitrope® in patients with growth hormone deficiency: snapshot analysis of PATRO Adults study in the Italian population

PURPOSE

PATRO adults is an ongoing, multicenter, observational, post-marketing surveillance study aimed at investigating the long-term safety (primary endpoint) and effectiveness (secondary endpoint) of the recombinant human growth hormone (rhGH) Omnitrope® during routine clinical practice. This report describes data from Italian participants in PATRO Adults with growth hormone deficiency (GHD), up to August 2017.

METHODS

Participants were adults (aged > 18 years) with GHD requiring rhGH therapy and were prescribed Omnitrope®, including those who had previously received another rhGH product. Adverse events (AEs) were evaluated in all study participants. Data were collected on insulin-like growth factor (IGF)-I levels and cardiovascular risk factors, including blood pressure, lipids, and anthropometric parameters.

RESULTS

From September 2007 to August 2017, 88 patients (mean age 48.9 years, 58.0% male) were enrolled at 8 sites in Italy. The mean treatment duration with Omnitrope® was 51.5 ± 37 months. AEs occurred in 54 patients; the most common were asthenia (20.5%), headache (14.8%), and arthralgia (13.6%). Serious AEs occurred in 22 patients (25%), including pneumonia (n = 2) and renal failure (n = 2). Neoplasms (2 benign and 1 malignant) developed in three patients, but none were considered to be drug-related. There were no significant changes in fasting glucose or glycosylated hemoglobin (HbA1c) during the study period. Long-term Omnitrope® therapy showed slight positive effects on lipid profile, while no significant changes were observed in body weight and BMI during the study.

CONCLUSION

This snapshot analysis of Italian participants in PATRO Adults confirmed the long-term safety and effectiveness of Omnitrope® in adults with GHD.

Body Composition Changes with Long-term Pegvisomant Therapy of Acromegaly

Context

In active acromegaly, the lipolytic and insulin antagonistic effects of growth hormone (GH) excess alter adipose tissue (AT) deposition, reduce body fat, and increase insulin resistance. This pattern reverses with surgical therapy. Pegvisomant treats acromegaly by blocking GH receptor (GHR) signal transduction and lowering insulin-like growth factor 1 (IGF-1) levels. The long-term effects of GHR antagonist treatment of acromegaly on body composition have not been studied.

Methods

We prospectively studied 21 patients with active acromegaly who were starting pegvisomant. Body composition was examined by whole body magnetic resonance imaging, proton magnetic resonance spectroscopy of liver and muscle and dual-energy x-ray absorptiometry, and endocrine and metabolic markers were measured before and serially during 1.0 to 13.4 years of pegvisomant therapy. The data of patients with acromegaly were compared with predicted and to matched controls.

Results

Mass of visceral AT (VAT) increased to a peak of 187% (1.56-229%) (P < .001) and subcutaneous AT (SAT) to 109% (–17% to 57%) (P = .04) of baseline. These remained persistently and stably increased, but did not differ from predicted during long-term pegvisomant therapy. Intrahepatic lipid rose from 1.75% to 3.04 % (P = .04). Although lean tissue mass decreased significantly, skeletal muscle (SM) did not change. IGF-1 levels normalized, and homeostasis model assessment insulin resistance and HbA1C were lowered.

Conclusion

Long-term pegvisomant therapy is accompanied by increases in VAT and SAT mass that do not differ from predicted, stable SM mass and improvements in glucose metabolism. Long-term pegvisomant therapy does not produce a GH deficiency-like pattern of body composition change.

Combined resistance and aerobic exercise intervention improves fitness, insulin resistance and quality of life in survivors of childhood haemopoietic stem cell transplantation with total body irradiation

PURPOSE

To investigate the effects of a supervised combined resistance and aerobic training programme on cardiorespiratory fitness, body composition, insulin resistance and quality of life (QoL) in survivors of childhood haematopoietic stem cell transplantation (HSCT) with total body irradiation (TBI).

PARTICIPANTS

HSCT/TBI survivors (n = 20; 8 females). Mean (range) for age at study and time since HSCT/TBI was 16.7 (10.9-24.5) and 8.4 (2.3-16.0) years, respectively.

METHODS

After a 6-month run-in, participants undertook supervised 45- to 60-minute resistance and aerobic training twice weekly for 6 months, with a 6-month follow-up. The following assessments were made at 0, 6 (start of exercise programme), 12 (end of exercise programme) and 18 months: Body composition via dual energy X-ray absorptiometry, homeostatic model assessment of insulin resistance (HOMA-IR), cardiorespiratory fitness (treadmill-based peak rate of oxygen uptake (VO₂ peak) test), QoL questionnaires (36-Item Short Form Health Survey (SF-36) and Minneapolis-Manchester Quality of Life Instrument (MMQL).

RESULTS

Results expressed as mean (standard deviation) or geometric mean (range). There were significant improvements in VO₂ peak (35.7 (8.9) vs 41.7 (16.1) mL/min/kg, P = 0.05), fasted plasma insulin (16.56 (1.48-72.8) vs 12.62 (1.04-54.97) mIU/L, P = 0.03) and HOMA-IR (3.65 (0.30-17.26) vs 2.72 (0.22-12.89), P = 0.02) after the exercise intervention. There were also significant improvements in the SF-36 QoL general health domain (69.7 (14.3) vs 72.7 (16.0), P = 0.001) and the MMQL school domain (69.1 (25.2) vs (79.3 (21.6), P = 0.03) during the exercise intervention. No significant changes were observed in percentage body fat, fat mass or lean mass.

CONCLUSION

The supervised 6-month combined resistance and aerobic exercise programme significantly improved cardiorespiratory fitness, insulin resistance and QoL in childhood HSCT/TBI survivors, with no change in body composition, suggesting a metabolic training effect on muscle. These data support a role for targeted physical rehabilitation services in this group at high risk of diabetes and cardiovascular disease.

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.

Review of WADA Prohibited Substances: Limited Evidence for Performance-Enhancing Effects

The World Anti-Doping Agency is responsible for maintaining a Prohibited List that describes the use of substances and methods that are prohibited for athletes. The list currently contains 23 substance classes, and an important reason for the existence of this list is to prevent unfair competition due to pharmacologically enhanced performance. The aim of this review was to give an overview of the available evidence for performance enhancement of these substance classes. We searched the scientific literature through PubMed for studies and reviews evaluating the effects of substance classes on performance. Findings from double-blind, randomized controlled trials were considered as evidence for (the absence of) effects if they were performed in trained subjects measuring relevant performance outcomes. Only 5 of 23 substance classes show evidence of having the ability to enhance actual sports performance, i.e. anabolic agents, β2-agonists, stimulants, glucocorticoids and β-blockers. One additional class, growth hormone, has similar evidence but only in untrained subjects. The observed effects all relate to strength or sprint performance (and accuracy for β-blockers); there are no studies showing positive effects on reliable markers of endurance performance. For 11 classes, no well-designed studies are available, and, for the remaining six classes, there is evidence of an absence of a positive effect. In conclusion, for the majority of substance classes, no convincing evidence for performance enhancement is available, while, for the remaining classes, the evidence is based on a total of only 266 subjects from 11 studies.

The heart in growth hormone (GH) deficiency and the cardiovascular effects of GH

Besides its effects on longitudinal growth in childhood and its metabolic effects with consequences on body composition and lipid levels, growth hormone (GH) has important roles on maintaining the structure and function of the normal adult heart. GH/insulin like growth factor-I (IGF-I) also interacts with the vascular system and plays a role in the regulation of vascular tone. GH deficiency (GHD) in adulthood is associated with increased fat mass (particularly visceral) and abnormal lipid profile, which may contribute to the excess cardiovascular mortality observed in patients with panhypopituitarism. Treatment with GH improved body composition (by increasing lean mass and decreasing fat mass) and improved lipid profile. It also has beneficial effects on vascular walls. The improvement in cardiovascular morbidity and mortality induced by GH is less clear as data are scarce and obtained on small populations. The importance of alteration in cardiac morphology and function observed in GHD is debated, particularly when cardiac magnetic resonance is used rather than echocardiography. The effects of treatment with GH on heart function and morphology are modest when studied by echocardiography.

Increased circulating levels of irisin are associated with cardiovascular risk factors in subjects with acromegaly

AIMS

Irisin, a peptide secreted from muscle and adipose tissues, is associated with insulin resistance as well as metabolic and cardiovascular diseases. Acromegaly is a rare disorder caused by overproduction of growth hormone (GH) and is associated with functional and structural differentiation of adipose and muscle tissues. Acromegalic subjects are also at risk of vascular diseases and metabolic dysfunctions. We aimed to determine the altered levels of irisin in subjects with active acromegaly and controlled acromegaly and in controls, and to ascertain whether there is an association between irisin and hormonal and cardiometabolic parameters.

METHODS

We enrolled 40 subjects with active acromegaly, 30 subjects with controlled acromegaly, and 40 control subjects of matched age, gender, BMI, and occurrence of hypertension, diabetes, and metabolic syndrome distribution in the present cross-sectional study. Hormonal and metabolic parameters, carotid intima media thickness (cIMT), and epicardial fat thickness (EFT) of the subjects were evaluated. Irisin levels were measured using ELISA.

RESULTS

Circulating levels of irisin were significantly higher in acromegalic subjects compared to both controlled acromegalic subjects and controls. Moreover, irisin levels were elevated in controlled acromegalic subjects compared to controls. Irisin displayed a positive correlation with insulin resistance, cIMT, EFT, BMI, GH, and insulin-like growth factor (IGF-1) in acromegalic subjects. Irisin levels were independently associated with cIMT and EFT according to multiple regression analyses. There was an independent relationship between irisin and IGF-1.

CONCLUSIONS

Elevated irisin levels in acromegalic subjects were associated with cIMT and EFT, suggesting that irisin is a surrogate marker for cardiovascular risk in acromegalic subjects.

Physical exercise improves functional capacity and quality of life in patients with acromegaly: a 12-week follow-up study

OBJECTIVE

Although the focus of acromegaly treatment is the hormonal control of the disease, a new perspective must be given to the functional rehabilitation of these patients, especially when considering the recent increase in survival. The aim of this study was to evaluate the effects of therapist-oriented home rehabilitation (TOHR) on patients with acromegaly.

PATIENTS AND METHODS

Seventeen adults with acromegaly followed an exercise programme from a booklet with instructions for each exercise prescribed, for 2 months, and were reassessed after 1 month of washout. At each of the 3 timepoints (before and after the intervention and at the 1-month follow-up), the participants were subjected to the following assessments: body composition through bioimpedance, health-related quality of life (HRQoL) using the Acromegaly Quality of Life (AcroQoL) questionnaire, general fatigue through the Functional Assessment of Chronic Illness Therapy-Fatigue scale, handgrip strength, lower extremity functionality using isometric dynamometry and the Lower Extremity Functional Scale (LEFS), body balance through stabilometry, and functional capacity through 6-minute walking distance (6MWD).

RESULTS

After performing TOHR, improvements in general fatigue, quadriceps muscle strength, LEFS, 6MWD, balance control and all AcroQoL dimensions were observed (all P < 0.05). After 1 month of washout, however, these gains were lost for all parameters, except the LEFS and balance control.

CONCLUSIONS

In acromegaly, TOHR results in improvements in muscle function, functional capacity, general fatigue, body balance, and HRQoL. Large randomized controlled trials are needed to replicate these benefits and to recommend rehabilitation, especially for those with long-term illness.

Static and dynamic balances of patients with acromegaly and impact of exercise on balance

PURPOSE

Patients with acromegaly may have balance abnormalities due to changes in body composition. We aim to compare static and dynamic balances in patients with acromegaly and healthy volunteers, and to evaluate the effects of exercise on balance in patients with acromegaly.

METHODS

This prospective study included 25 patients with acromegaly followed at endocrinology clinic of Cerrahpasa Medical Faculty and 13 healthy volunteers. The acromegalic patients were divided into 2 groups. Group A (n = 11) attended an exercise program 3 days/week for 3 months, whereas group B (n = 14) and healthy volunteers (Group C) were exercise-free. Bipedal and unipedal stance static and dynamic balance tests were performed using a Prokin 252N device.

RESULTS

The ages, demographic characteristics, and body compositions were similar. In acromegalic patients, the static balance parameters of displacement of center-of-pressure in anterior-posterior direction (C.o.P.Y) while eyes open (p = 0.002) and on left leg (p = 0.001), in left-right direction (C.o.P.X) on right leg (p = 0.03), eyes-closed average medio-lateral velocity (AMLV) (p = 0.001) and the dynamic parameter of forward/backward front/right standard deviation (FBFRSD) (p = 0.02) were significantly different from healthy controls. When the exercise effect on balance was evaluated between group A and B, there were significant improvements in most parameters of dynamic balance measurements of both forward-backward and medial-lateral sway (FBFRSD, FBDME, and RLBLSD) (p = 0.02, p = 0.02, and p = 0.004, respectively) after exercise in group A.

CONCLUSIONS

Patients with acromegaly had impairments at various static and dynamic balance parameters, especially in posterior direction. After a 3-month exercise program, the dynamic balance profoundly improved, but static balance was relatively preserved in patients with acromegaly.

Growth Hormone Deficiency Following Traumatic Brain Injury

Traumatic brain injury (TBI) is fairly common and annually affects millions of people worldwide. Post traumatic hypopituitarism (PTHP) has been increasingly recognized as an important and prevalent clinical entity. Growth hormone deficiency (GHD) is the most common pituitary hormone deficit in long-term survivors of TBI. The pathophysiology of GHD post TBI is thought to be multifactorial including primary and secondary mechanisms. An interplay of ischemia, cytotoxicity, and inflammation post TBI have been suggested, resulting in pituitary hormone deficits. Signs and symptoms of GHD can overlap with those of TBI and may delay rehabilitation/recovery if not recognized and treated. Screening for GHD is recommended in the chronic phase, at least six months to a year after TBI as GH may recover in those with GHD in the acute phase; conversely, it may manifest in those with a previously intact GH axis. Dynamic testing is the standard method to diagnose GHD in this population. GHD is associated with long-term poor medical outcomes. Treatment with recombinant human growth hormone (rhGH) seems to ameliorate some of these features. This review will discuss the frequency and pathophysiology of GHD post TBI, its clinical consequences, and the outcomes of treatment with GH replacement.

Pituitary dysfunction due to sports-related traumatic brain injury

PURPOSE

After traumatic brain injury was accepted as an important etiologic factor of pituitary dysfunction (PD), awareness of risk of developing PD following sports-related traumatic brain injury (SR-TBI) has also increased. However there are not many studies investigating PD following SR-TBIs yet. We aimed to summarize the data reported so far and to discuss screening algorithms and treatment strategies.

METHODS

Recent data on pituitary dysfunction after SR-TBIs is reviewed on basis of diagnosis, clinical perspectives, therapy, screening and possible prevention strategies.

RESULTS

Pituitary dysfunction is reported to occur in a range of 15-46.6% following SR-TBIs depending on the study design. Growth hormone is the most commonly reported pituitary hormone deficiency in athletes. Pituitary hormone deficiencies may occur during acute phase after head trauma, may improve with time or new deficiencies may develop during follow-up. Central adrenal insufficiency is the only and most critical impairment that requires urgent detection and replacement during acute phase. Decision on replacement of growth hormone and gonadal deficiencies should be individualized. Moreover these two hormones are abused by many athletes and a therapeutic use exemption from the league's drug policy may be required.

CONCLUSIONS

Even mild and forgotten SR-TBIs may cause PD that may have distressing consequences in some cases if remain undiagnosed. More studies are needed to elucidate epidemiology and pathophysiology of PD after SR-TBIs. Also studies to establish screening algorithms for PD as well as strategies for prevention of SR-TBIs are urgently required.

Clinical and functional variables can predict general fatigue in patients with acromegaly: an explanatory model approach

OBJECTIVE

To evaluate whether hormonal profile, arterial function, and physical capacity are predictors of fatigue in patients with acromegaly. Subjects and methods: This is a cross-sectional study including 23 patients. The subjects underwent a Modified Fatigue Impact Scale (MFIS) assessment; serum growth hormones (GH) and IGF-1 measurements; pulse wave analysis comprising pulse wave velocity (PWV), arterial compliance (AC), and the reflection index (IR1,2); dominant upper limb dynamometry (DYN); and the six-minute walking distance test (6MWT). Multiple linear regression models were used to identify predictors for MFIS. The coefficient of determination R2 was used to assess the quality of the models' fit. The best model was further analyzed using a calibration plot and a limits of agreement (LOA) plot.

RESULTS

The mean ± SD values for the participants' age, MFIS, PWV, AC, IR1,2, DYN, and the distance in the 6MWT were 49.4 ± 11.2 years, 31.2 ± 18.9 score, 10.19 ± 2.34 m/s, 1.08 ± 0.46 x106 cm5/din, 85.3 ± 29.7%, 33.9 ± 9.3 kgf, and 603.0 ± 106.1 m, respectively. The best predictive model (R2 = 0.378, R2 adjusted = 0.280, standard error = 16.1, and P = 0.026) comprised the following regression equation: MFIS = 48.85 - (7.913 × IGF-I) + (1.483 × AC) - (23.281 × DYN).

CONCLUSION

Hormonal, vascular, and functional variables can predict general fatigue in patients with acromegaly.

Adult individuals with congenital, untreated, severe isolated growth hormone deficiency have satisfactory muscular function

PURPOSE

While growth hormone (GH) and the insulin-like growth factor type I (IGF-I) are known to exert synergistic actions on muscle anabolism, the consequences of prolonged GH deficiency (GHD) on muscle function have not been well defined. We have previously described a large cohort of subjects with isolated GHD (IGHD) caused by a mutation in the GH-releasing hormone receptor gene, with low serum levels of GH and IGF-I. The aim of this study was to assess muscular function in these IGHD subjects.

METHODS

A total of 31 GH-naïve IGHD (16 males) and 40 control (20 males) subjects, matched by age and degree of daily physical activity, were enrolled. Fat free mass was measured by bioelectrical impedance; muscle strength by dynamometry of handgrip, trunk extension, and knee extension; myoelectric activity and muscle fatigue by fractal dimension; conduction velocity in vastus medialis, rectus femoris, and vastus lateralis muscles by surface electromyography.

RESULTS

The IGHD group showed higher knee extension strength both when corrected for weight and fat free mass, and higher handgrip and trunk extension strength corrected by fat free mass. They also exhibit higher conduction velocity of the muscles vastus medialis, rectus femoris, and vastus lateralis, but lower free fat mass and myoelectric activity of the vastus medialis, rectus femoris and vastus lateralis. There were no differences between the two groups in fractal dimension in all studied muscles.

CONCLUSION

Individuals with untreated IGHD have better muscle strength parameters adjusted for weight and fat free mass than controls. They also exhibit greater peripheral resistance to fatigue, demonstrating satisfactory muscle function.

Decreased quality of life (QoL) in hypopituitary patients: involvement of glucocorticoid replacement and radiation therapy

PURPOSE

Hypopituitary patients are assumed to have decreased QoL due to GHD. However, in placebo controlled trials, the effects of GH replacement are no different from placebo. Hydrocortisone dose > 20 mg/day and pituitary radiation are independently associated with poorer QoL. We assessed QoL in panhypopituitary GH- deficient patients never treated with GH.

METHODS

Study group was divided into: (a) surgery followed by radiation (n = 21) and (b) surgery alone (n = 32). Mean duration of GHD was 71.4 ± 7.8 months and mean daily hydrocortisone dose was 15 ± 0.7 mg. Control group had transnasal surgery for benign sinus conditions (n = 54).

RESULTS

AGHDA scores were significantly worse in the entire study group compared to controls (8.1 ± 1.0 vs. 5.1 ± 0.9, p = 0.03). In patients with history of radiation therapy AGHDA scores were significantly worse than in controls (9.1 ± 1.5, p = 0.02) and SNOT-22 (Sino-Nasal Outcome Test) scores were also significantly worse (15.8 ± 2.0 vs. 23.2 ± 3.5, p = 0.04). However, AGHDA scores in patients without history of radiation and on "physiological" dose of hydrocortisone were similar to those in controls (5.1 ± 0.9 vs. 7.3 ± 1.3, p = 0.17).

CONCLUSIONS

Replacement with hydrocortisone doses not exceeding 20 mg/day and avoidance of radiation therapy was accompanied by normal QoL in patients not replaced with GH. Thus, we suggest that the decreased QoL in hypopituitary patients may not be due to GH deficiency per se, but rather to high hydrocortisone doses and to aftereffects of cranial radiation.

Resistance exercise alone improves muscle strength in growth hormone deficient males in the transition phase

Background During the transition phase (TP), patients with growth hormone deficiency (GHD) exhibit decreased muscle strength. Studies assessing the effects of resistance exercise alone on muscle strength in these individuals are scarce. The objective of this study was to evaluate the effects of a program of resistance exercise (PRE) on parameters of muscle strength in subjects in the TP and with childhood-onset GHD treated with recombinant GH (rGH). Methods Sixteen male patients were enrolled and divided into two groups: GHD (n=9) and GH sufficiency (GHS, n=7). Patients with GHD underwent a 12-week PRE followed by another 12-week PRE plus rGH, while GHS patients underwent a 12-week PRE alone. Dynamic knee muscle strength was evaluated using an isokinetic dynamometer. Results Before PRE, there were significant differences between the groups regarding the results of flexor peak torque (FPT) normalized to body weight (BW-FPT) in the dominant (DO, p=0.008) and non-dominant (ND, p=0.01) limbs, and in the agonist/antagonist (A/A) ratio in the DO (p=0.02) and ND (p=0.006) limbs. After PRE in the GHD group, values of FPT and BW-FPT in both limbs increased significantly (p<0.001) and independently of rGH, while the A/A ratio value improved significantly (p<0.001) in the ND limb. Conclusions A short period of PRE alone was sufficient to improve parameters of muscle strength in young male adults with childhood-onset GHD.

The relationship between serum IGF-1, handgrip strength, physical performance and falls in elderly men and women

OBJECTIVE

Human aging is accompanied by a decrease in growth hormone secretion and serum insulin-like growth factor (IGF)-1 levels. Also, loss of muscle mass and strength and impairment of physical performance, ending in a state of frailty, are seen in elderly. We aimed to investigate whether handgrip strength, physical performance and recurrent falls are related to serum IGF-1 levels in community-dwelling elderly.

DESIGN

Observational cohort study (cross-sectional and prospective).

METHODS

We studied the association between IGF-1 and handgrip strength, physical performance and falls in participants of the Longitudinal Aging Study Amsterdam. A total of 1292 participants were included (633 men, 659 women). Serum IGF-1 levels were divided into quartiles (IGF-1-Q1 to IGF-1-Q4). Data on falls were collected prospectively for a period of 3 years. All analyses were stratified for age and physical activity and adjusted for relevant confounders.

RESULTS

Men with a low physical activity score in IGF-1-Q1 and IGF-1-Q2 of the younger age group had a lower handgrip strength compared to IGF-1-Q4. In younger more active males in IGF-1-Q2 physical performance was worse. Recurrent fallers were less prevalent in older, low active males with low IGF-1 levels. In females, recurrent fallers were more prevalent in older, more active females in IGF-1-Q2. IGF-1 quartile may predict changes in handgrip strength and physical performance in men and women.

CONCLUSIONS

Our results indicate that lower IGF-1 levels are associated with lower handgrip strength and worse physical performance, but less recurrent fallers especially in men. Associations were often more robust in IGF-1-Q2. Future studies on this topic are desirable.

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.

Deregulation of the growth hormone/insulin-like growth factor-1 axis in adults with cystic fibrosis

PURPOSE

Patients with cystic fibrosis (CF) present with signs and symptoms that overlap with those of adult growth hormone deficiency (GHD) syndrome: loss of muscle mass, bone fragility and lower stress tolerance. In literature, the prevalence of GHD in pediatric CF patients is higher than general population, but these studies have been performed on children with growth delay. To our knowledge, there are no studies on adult patients. The aim of this paper is to evaluate GH-IGF1 axis in an adult CF population.

METHODS

Fifty clinically stable adult patients, 30 males; age 36 ± 2 years; BMI 21.39 ± 0.22 kg/m² and FEV₁ 67 ± 4% were studied. Data regarding glycometabolic status and results of pituitary, thyroid, parathyroid, gonadal and adrenal function tests were recorded. All patients underwent a GH releasing hormone (GHRH) + Arginine stimulation test to confirm a GHD.

RESULTS

GHRH + Arginine test revealed the presence of GHD in 16 patients (32%); specifically 7 patients had a severe deficiency and 9 a partial deficiency.

CONCLUSIONS

Adult patients with CF may show GHD. These patients should be followed over time to assess if the GHD could impact the clinical progression of CF.

Elevated (Pro)renin Receptor Expression Contributes to Maintaining Aerobic Metabolism in Growth Hormone Deficiency

Context

Growth hormone deficiency (GHD) leads to obesity and may induce tissue hypoxia. As (pro)renin receptor [(P)RR] is reported to contribute to the aerobic metabolism by stabilizing pyruvate dehydrogenase (PDH), it may play a substantial role in GHD.

Objective

We aimed to investigate serum soluble (P)RR [s(P)RR] concentration, the origin of s(P)RR, and significance of (P)RR in GHD.

Design, Setting, and Participants

Serum s(P)RR concentration was examined in 72 patients with pituitary diseases, including 32 patients with severe GHD (SGHD) and after GH replacement in 16 SGHD patients. Leptin-deficient ob/ob obese mice were treated with pegvisomant, a GH receptor antagonist, to explore the source of elevated serum s(P)RR in GHD. Adipocytes were cultured with 5% O₂ to examine the effects of hypoxia.

Results

Serum s(P)RR concentration was higher in patients with SGHD than in those without SGHD. Obesity was the important determinant of s(P)RR concentration. Serum s(P)RR concentration significantly decreased after GH replacement in SGHD patients. (P)RR mRNA expression was increased specifically in the adipose tissue (AT) of pegvisomant-treated obese mice compared with that of control obese mice. Hypoxia in cultured adipocytes increased (P)RR expression without affecting the PDH E1 β subunit (PDHB) expression; however, with (P)RR knockdown by small interfering RNA, hypoxia significantly decreased the expression of PDHB.

Conclusion

GHD patients showed increased serum s(P)RR concentration, possibly caused by obesity and hypoxia. (P)RR expression in AT of GHD patients may be elevated to help maintain aerobic metabolism under hypoxia. Thus, the elevated serum s(P)RR level may reflect hypoxia in ATs.

Effects of Growth Hormone Replacement on Peripheral Muscle and Exercise Capacity in Severe Growth Hormone Deficiency

OBJECTIVE

The aim of this study is to evaluate the effect of growth hormone therapy (rGH) on mitochondrial function on peripheral muscle and to correlate with exercise capacity in subjects with severe adult growth hormone deficiency (GHD).

DESIGN

Six months, double-blind, randomized, crossover, placebo-controlled trial of subcutaneous rGH in 17 patients with GHD.

MEASUREMENTS

Quadriceps muscle biopsies were obtained at baseline, 3 months, and 6 months to measure succinate dehydrogenase (SDH) to assess mitochondrial activity. Exercise capacity was measured with cardiopulmonary exercise testing. Lipids, glycemic parameters, and body fat levels were also measured.

RESULTS

Serum insulin-like growth factor 1 (IGF1) levels reduced fat mass by 3.2% (p < 0.05) and normalized with rGH in the active phase (p < 0.005). Patients showed an increase in SDH (p < 0.01) from base line that differed between placebo and rGH therapy treatment groups (p < 0.05): those treated by rGH followed by placebo showed a significant increase in SDH (p < 0.001) followed by a decrease, with a significant between group difference at the end of 6 months (p < 0.05). No significant improvements or correlation with exercise capacity was found.

CONCLUSION

Short-term rGH for 3 months normalized IGF1 levels, reduced fat mass, and had a significant effect on mitochondrial function, but exercise capacity was unchanged.

CLINICAL TRIAL REGISTRATION

Number ISRCTN94165486.

Comparison of Walking, Muscle Strength, Balance, and Fear of Falling Between Repeated Fall Group, One-time Fall Group, and Nonfall Group of the Elderly Receiving Home Care Service

PURPOSE

The purpose of this study was to provide information to develop a program to prevent repeated falls by analyzing the difference in gait, muscle strength, balance, and fear of falling according to their fall experience.

METHODS

The study subjects were 110 elderly individuals aged over 60 years who agreed to their participation in this research. The study participants were categorized into a repeated fall group (n = 40), a one-time fall group (n = 15), and a nonfall group (n = 46) of the elderly. Measurements of gait, muscle strength, balance, and fear of falling were taken in each group.

RESULTS

With regard to gait, there were significant differences among three groups in gait cycle (F = 3.50, p = .034), speed (F = 13.06, p < .001), and cadence (F = 5.59, p = .005). Regarding muscle strength in the upper and lower limbs, statistically significant differences were shown among three groups in muscle strength of upper (F = 16.98, p < .001) and lower (F = 10.55, p < .001) limbs. With regard to balance, the nonfall group had significantly greater results than the one-time fall group and repeated fall group in dynamic balance (F = 10.80, p < .001) and static balance (F = 8.20, p = .001). In the case of the fear of falling, the repeated fall group had significantly higher score than other two groups (F = 20.62, p < .001).

CONCLUSION

This study suggests that intervention program should be tailored to fall risk factors to enhance gait and balance and lower body muscle strength and reduce the fear of falling to prevent repeated incidences of falls in this population.

The Effects of Physical Training are Varied and Occur in an Exercise Type-Dependent Manner in Elderly Men

Regular exercise can decrease the deleterious effects of aging and limit the development and progression of chronic disease in elderly people, depending on the type, intensity, frequency, and duration of exercise. This study aimed to investigate the potential protective effects of different physical training programs on oxidative stress parameters and inflammatory and neurotrophic mediators in the serum of elderly men. Healthy male volunteers [60 to 80 years; n=55] were divided into four groups: control [Ctr, n=14], aerobic training on dry land [ATdl, n=12]; and combined training on dry land [CTdl, n=12] or in water [CTw, n=17]. The training protocols were performed over 8 weeks, three times per week. Each 1 h session included 5 min warming-up exercise, 50 min specific training [aerobic, strength, or combined], and 5 min stretching. Blood samples were drawn 72 h before [baseline] the beginning of the 8 weeks’ protocol and 48 h after the last training session, processed, and the serum was aliquoted and stored at -70 °C until biochemical assessment of oxidative damage, antioxidant system and neurotrophic, growth and inflammatory factors. Elevated BDNF or IGF-1 levels were observed in the ATdl or CTdl groups, respectively. Overall oxidative stress parameters were improved including reduced lipid oxidative damage and increased thioredoxin reductase and glutathione peroxidase activities and total glutathione. Significant decreases in the inflammatory mediators IL-6 and IL-8 were observed; IL-6 was more susceptible to the effects of type of physical training. Thus, the effects of training in elderly men vary in an exercise type-dependent manner.

Growth Hormone Improves Cardiopulmonary Capacity and Body Composition in Children With Growth Hormone Deficiency

CONTEXT

Growth hormone deficiency (GHD) in children may be associated with early cardiovascular risk factors and alterations in left ventricular (LV) structure and function; data on cardiopulmonary functional capacity are lacking.

OBJECTIVES

Aim of the study was to evaluate the effect of GHD and growth hormone (GH) therapy on cardiopulmonary functional capacity, left and right cardiac structure and function, and body composition in children and adolescents.

DESIGN

Prospective, case-control study.

PATIENTS AND METHODS

Twenty-one untrained GHD children (11.3 ± 0.8 years) underwent cardiopulmonary exercise testing, echocardiography and dual-energy x-ray absorptiometry, before and after 12 months of GH therapy. Twenty-one controls matched for sex, pubertal status, body mass index, and physical activity (PA) were evaluated at baseline and after 1 year.

RESULTS

At baseline, GHD patients showed reduced LV mass (LVM; 63.32 ± 7.80 vs 80.44 ± 26.29 g/m2, P = 0.006), peak oxygen consumption (VO2peak; 22.92 ± 4.80 vs 27.48 ± 6.71 mL/Kg/min, P = 0.02), peak workload (80.62 ± 29.32 vs 103.76 ± 36.20 W, P = 0.02), and O2 pulse (4.93 ± 1.30 vs 7.67 ± 2.93 mL/beat, P = 0.0003), compared with controls. GHD patients also exhibited lower lean body mass (LBM 65.36 ± 7.84% vs 76.13 ± 8.23%, P < 0.001), and higher fat mass (FM 30.84 ± 7.92% vs 22.19 ± 8.18%, P = 0.001) than controls. GH therapy resulted in a significant increase of LVM (72.01 ± 15.88, P = 0.03), VO2peak (26.80 ± 4.97; P = 0.01), peak workload (103.67 ± 32.24, P = 0.001), O2 pulse (6.64 ± 1.68, P = 0.0007), and LBM (75.36 ± 7.59%, P = 0.0001), with a reduction in FM (22.62 ± 7.73%, P = 0.001). No difference was found in either left or right ventricular function.

CONCLUSION

Our results suggest that cardiac structure, body composition and cardiopulmonary functional capacity are impaired in children with untreated GHD and can be restored after short-term GH replacement therapy.

Muscle strength in patients with acromegaly at diagnosis and during long-term follow-up

OBJECTIVE

Patients with acromegaly have decreased body fat (BF) and increased extracellular water (ECW) and muscle mass. Although there is a lack of systematic studies on muscle function, it is believed that patients with acromegaly may suffer from proximal muscle weakness despite their increased muscle mass. We studied body composition and muscle function in untreated acromegaly and after biochemical remission.

DESIGN

Prospective observational study.

METHODS

Patients with acromegaly underwent measurements of muscle strength (dynamometers) and body composition (four-compartment model) at diagnosis (n = 48), 1 year after surgery (n = 29) and after long-term follow-up (median 11 years) (n = 24). Results were compared to healthy subjects.

RESULTS

Untreated patients had increased body cell mass (113 ± 9% of predicted) and ECW (110 ± 20%) and decreased BF (67 ± 7.6%). At one-year follow-up, serum concentration of IGF-I was reduced and body composition had normalized. At baseline, isometric muscle strength in knee flexors and extensors was normal and concentric strength was modestly increased whereas grip strength and endurance was reduced. After one year, muscle strength was normal in both patients with still active disease and patients in remission. At long-term follow-up, all patients were in remission. Most muscle function tests remained normal, but isometric flexion and the fatigue index were increased to 153 ± 42% and 139 ± 28% of predicted values, respectively.

CONCLUSIONS

Patients with untreated acromegaly had increased body cell mass and normal or modestly increased proximal muscle strength, whereas their grip strength was reduced. After biochemical improvement and remission, body composition was normalized, hand grip strength was increased, whereas proximal muscle fatigue increased.

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.

Sex steroids and the GH axis: Implications for the management of hypopituitarism

Growth hormone (GH) regulates somatic growth, substrate metabolism and body composition. Sex hormones exert profound effect on the secretion and action of GH. Estrogens stimulate the secretion of GH, but inhibit the action of GH on the liver, an effect that occurs when administered orally. Estrogens suppress GH receptor signaling by stimulating the expression proteins that inhibit cytokine receptor signaling. This effect of estrogens is avoided when physiological doses of estrogens are administered via a non-oral route. Estrogen-like compounds, such as selective estrogen receptor modulators, possess dual properties of inhibiting the secretion as well as the action of GH. In contrast, androgens stimulate GH secretion, driving IGF-1 production. In the periphery, androgens enhance the action of GH. The differential effects of estrogens and androgens influence the dose of GH replacement in patients with hypopituitarism on concomitant treatment with sex steroids. Where possible, a non-oral route of estrogen replacement is recommended for optimizing cost-benefit of GH replacement in women with GH deficiency. Adequate androgen replacement in conjunction with GH replacement is required to achieve the full anabolic effect in men with hypopituitarism.

Controversies in the risk of neoplasia in GH deficiency

Growth hormone (GH) replacement in GH deficient (GHD) children secures normal linear growth, while in GHD adults it improves metabolic status, body composition and quality of life. Safety of GH treatment is an important issue in particular concerning the controversy of potential cancer risk. Unlike in congenital IGF-1 deficiency, there is no complete protection against cancer in GHD patients. Important modifiable risk factors in GHD patients are obesity, insulin resistance, sedentary behavior, circadian rhythm disruption, chronic low grade inflammation and concomitant sex hormone replacement. Age, family history, hereditary cancer predisposition syndromes or cranial irradiation may present non-modifiable risk factors. Quantifying the risk of cancer in relation to GH therapy in adult GHD patients is complex. There is evidence that links GH to cancer occurrence or promotion, but the evidence is progressively weaker when moving from in vitro studies to in vivo animal studies to epidemiological studies and finally to studies on GH treated patients. GH-IGF inhibition in experimental animals leads to decreased cancer incidence and progression. Epidemiological studies suggest an association of high normal circulating IGF-1 or GH to cancer incidence in general population. Data regarding cancer incidence in acromegaly are inconsistent but thyroid and colorectal neoplasias are the main source of concern. Replacement therapy with rhGH for GHD is generally safe. Overall the rate of de novo cancers was not increased in studies of GH-treated GHD patients. Additional caution is mandated in patients with history of cancer, strong family history of cancer and with advancing age. Childhood cancer survivors may be at increased risk for secondary neoplasms compared with general population. In this subgroup GH therapy should be used cautiously and with respect to other risk factors (cranial irradiation etc). We believe that the benefits of GH therapy against the morbidity of untreated GH deficiency outweigh the theoretical cancer risk. Proper monitoring of GH treatment with diligent cancer surveillance remains essential.

Muscle and skeletal health in children and adolescents with GH deficiency

In addition to promoting linear growth, GH plays a key role in the regulation of bone and muscle development and metabolism. Although GH deficiency is frequently listed among the causes of secondary osteoporosis in children, its impact on bone and muscle health and on fracture risk is still not completely established. Current data suggest that childhood-onset GH deficiency can affect bone and muscle mass and strength, with GH replacement therapy exerting beneficial effects. Moreover, GH withdrawal at final height can result in reduced peak bone and muscle mass, potentially leading to increased fracture risk in adulthood. Thus, the muscle-bone unit in GH deficient subjects should be monitored during childhood and adolescence in order to prevent osteoporosis and increased fracture risk and GH replacement should be tailored to ensure an optimal bone and muscle health.

Functional Changes after Recombinant Human Growth Hormone Replacement in Patients with Chronic Traumatic Brain Injury and Abnormal Growth Hormone Secretion

We explored the effects of recombinant human growth hormone (rhGH) replacement on physical and cognitive functioning in subjects with a moderate-to-severe traumatic brain injury (TBI) with abnormal growth hormone (GH) secretion. Fifteen individuals who sustained a TBI at least 12 months prior to study enrollment were identified as having abnormal GH secretion by glucagon stimulation testing (maximum GH response less than 8 ng/mL). Peak cardiorespiratory capacity, body composition, and muscle force testing were assessed at baseline and one year after rhGH replacement. Additionally, standardized neuropsychological tests that assess memory, processing speed, and cognitive flexibility, as well as self-report inventories related to depression and fatigue, were administered at baseline and 1 year after rhGH replacement. Comparison tests were performed with proper post hoc analyses. All analyses were carried out at α < 0.05. Peak O₂ consumption, peak oxygen pulse (estimate of cardiac stroke volume), and peak ventilation all significantly increased (p < 0.05). Maximal isometric and isokinetic force production were not altered. Skeletal muscle fatigue did not change but the perceptual rating of fatigue was reduced by ∼25% (p = 0.06). Cognitive performance did not change significantly over time, whereas self-reported symptoms related to depression and fatigue significantly improved. The observed changes suggest that rhGH replacement has a positive impact on cardiorespiratory fitness and a positive impact on perceptual fatigue in survivors of TBI with altered GH secretion.

Growth hormone (GH) enhances anaerobic capacity: impact on physical function and quality of life in adults with GH deficiency

CONTEXT

Anaerobic capacity is impaired in adults with GH deficiency (GHD), adversely affecting physical function and quality of life (QoL).

OBJECTIVE

To investigate whether GH replacement improves anaerobic capacity, physical function and QoL in adults with GHD.

DESIGN

One-month double-blind placebo-controlled crossover study of GH (0·5 mg/day), followed by a 6-month open phase.

PATIENTS

A total of 18 adults with GHD.

MEASUREMENTS

Anaerobic power (watts) was assessed by the 30-s Wingate test, and aerobic capacity by the VO2 max (l/min) test. Physical functional was assessed by the stair climb test, chair stand test, 7-day pedometry and QoL by the AGHDA questionnaire. Lean body mass (LBM) was quantified by dual-energy X-ray absorptiometry.

RESULTS

GH replacement normalized IGF-1 levels during both study phases. During the 1-month placebo-controlled study, improvement in stair climb and chair stand performance was observed during GH and placebo treatment; however, there were no significant GH effects observed in any outcome measure compared to placebo. Six months of GH treatment significantly increased anaerobic power (P < 0·05), chair stand repetitions (P < 0·0001), daily step count (P < 0·05) and QoL scores (P < 0·001) compared to baseline measurements. GH treatment did not significantly improve VO2 max. Improvement in anaerobic power independently predicted an improvement in energy and vitality domain of QoL (P = 0·03).

CONCLUSIONS

GH replacement improves anaerobic capacity, physical function and QoL in a time-dependent manner in adults with GHD. Improvement in the anaerobic but not aerobic energy system is likely to underlie the improvement in QoL in patients with GHD during GH replacement.

Dyshomeostasis, obesity, addiction and chronic stress

When eating control is overridden by hedonic reward, a condition of obesity dyshomeostasis occurs. Appetitive hedonic reward is a natural response to an obesogenic environment containing endemic stress and easily accessible and palatable high-energy foods and beverages. Obesity dyshomeostasis is mediated by the prefrontal cortex, amygdala and hypothalamic-pituitary-adrenal axis. The ghrelin axis provides the perfect signalling system for feeding dyshomeostasis, affect control and hedonic reward. Dyshomeostasis plays a central role in obesity causation, the addictions and chronic conditions and in persons with diverse bodies. Prevention and treatment efforts that target sources of dyshomeostasis provide ways of reducing adiposity, ameliorating the health impacts of addiction and raising the quality of life in people suffering from chronic stress.

Estrogen receptor antagonism uncovers gender-dimorphic suppression of whole body fat oxidation in humans: differential effects of tamoxifen on the GH and gonadal axes

CONTEXT

Tamoxifen, a selective estrogen receptor modulator, suppresses GH secretion in women but not in men. It increases testosterone levels in men. As GH and testosterone stimulate fat metabolism, the metabolic consequences of tamoxifen may be greater in women than in men.

OBJECTIVE

To determine whether tamoxifen suppresses fat oxidation (Fox) to a greater degree in women than in men.

DESIGN

An open-label study of ten healthy postmenopausal women and ten healthy men receiving 2-week treatment with tamoxifen (20  mg/day).

ENDPOINT MEASURES

GH response to arginine stimulation, serum levels of IGF1, testosterone and LH (men only), sex hormone binding globulin (SHBG) and whole body basal and postprandial Fox.

RESULTS

In women, tamoxifen significantly reduced the mean GH response to arginine stimulation (Δ -87%, P<0.05) and circulating IGF1 levels (Δ -23.5±5.4%, P<0.01). Tamoxifen reduced postprandial Fox in women (Δ -34.6±10.3%; P<0.05). In men, tamoxifen did not affect the GH response to arginine stimulation but significantly reduced mean IGF1 levels (Δ -24.8±6.1%, P<0.01). Tamoxifen increased mean testosterone levels (Δ 52±14.2%; P<0.01). Fox was not significantly affected by tamoxifen in men.

CONCLUSION

Tamoxifen attenuated the GH response to stimulation and reduced postprandial Fox in women but not in men. We conclude that at a therapeutic dose, the suppressive effect of tamoxifen on fat metabolism is gender-dependent. Higher testosterone levels may mitigate the suppression of GH secretion and Fox during tamoxifen treatment in men.

What is the effect of peripheral muscle fatigue, pulmonary function, and body composition on functional exercise capacity in acromegalic patients?

[Purpose] The six-minute walk test (6MWT) is increasingly being used as an important tool for analyzing functional capacity in patients with multisystem disorders. The aim of this study was to evaluate the effect of body composition, peripheral muscle function, and pulmonary function on the six-minute walk distance (6MWD) in acromegalic patients. [Subjects and Methods] Thirty-two patients with active acromegaly, with a mean age of 48.6 ± 12.1 years, underwent an evaluation of body composition using electrical bioimpedance, isometric dynamometry with surface electromyography, tests of pulmonary function, and the 6MWT. [Results] The mean ± SD values for the 6MWD, fat-free mass (FFM), and maximal expiratory pressure (MEP) were 65.5 ± 11.7% predicted, 55.1 ± 10.6 kg, and 55.2 ± 16.8% predicted, respectively. There was a significant correlation between the 6MWD and the following parameters: the angle of the linear regression line obtained using the values of the median frequency electromyography signal over time during the fatigability test for the vastus medialis muscle (MDF, r=0.65), FFM (r=0.62), MEP (r=0.60), height⁽²⁾/resistance index (r=0.52), resistance (r=−0.50), and forced expiratory volume in 1 second (r=0.50). Multivariate analysis showed that MDF, FFM, and MEP were independent predictors of the 6MWD (R²=0.52). [Conclusion] The fatigability of the peripheral muscles, FFM, and MEP are the primary determinants of the 6MWD in acromegalics.

Growth hormone deficiency in treated acromegaly

Growth hormone deficiency (GHD) of the adult is characterized by reduced quality of life (QoL) and physical fitness, skeletal fragility, and increased weight and cardiovascular risk. Hypopituitarism may develop in patients after definitive treatment of acromegaly, but an exact prevalence of GHD in this population is still uncertain owing to limited awareness and the scarce and conflicting data available on this topic. Because acromegaly and GHD may yield adverse consequences on similar target systems, the final outcomes of some complications of acromegaly may be further affected by the occurrence of GHD. However, it is still largely unknown whether patients with post-acromegaly GHD may benefit from GH replacement. We review the diagnostic, clinical, and therapeutic aspects of GHD in adult patients treated for acromegaly.

Molecular effects of supraphysiological doses of doping agents on health

Supraphysiological doses of doping agents, such as T/DHT and GH/IGF-1, affect cellular pathways associated with apoptosis and inflammation.

Psychological profile and quality of life in patients with acromegaly in Greece. Is there any difference with other chronic diseases?

Several studies have shown that acromegaly is associated with increased psychological morbidity. However, it is not known whether this is attributed to acromegaly per se or to its chronicity as a debilitating disease affecting quality of life (QoL). The aim of this study was to assess psychological profile in acromegalics compared with those suffering from other serious chronic diseases and healthy controls. Secondary end points were QoL assessment and its association with mood disturbances. Comparative, cross-sectional study conducted in Northern Greece (2011-2012). The Greek versions of the Profile of Mood States (POMS) and AcroQoL questionnaires were used to assess psychological status and QoL, respectively. Forty acromegalics, 40 age- and sex-matched people with other chronic diseases and 80 healthy controls were included. No significant differences were identified between acromegalics and those suffering from other chronic diseases, regarding tension, anger, depression, confusion, fatigue and vigor. Compared with healthy controls, acromegalics suffered more from depression and anger, which remained significant after controlling for age, gender and marital status (p = 0.003 and p = 0.048, respectively). Negative predictors were female gender, macroadenomas and radiotherapy. AcroQoL scores were negatively associated with POMS subscales. Males had better QoL than females. Other than a negative association between AcroQoL-relationships subscale and disease duration, no association with other parameters was observed. Acromegaly has a negative impact on psychological status, which is worse than that of general population, but comparable to other chronic diseases. Mood disturbances are associated with impaired QoL, mainly in females and those with longer disease duration.

Posture and balance control in patients with acromegaly: results of a cross-sectional study

Acromegaly is a chronic debilitating disease that presents with multiple systemic manifestations, including changes in body composition, joint abnormalities, muscular impairment and visual disturbances. This study aimed to assess posture and body balance in acromegalic patients and to establish the correlation between these measures. Twenty-eight acromegalic patients and a similar number of control subjects matched for sex, age, weight, height and body mass index underwent postural evaluation using the photogrammetry and measurement of balance using the stabilometry in two tasks: feet apart, eyes open and feet together, eyes closed. In comparison with the control group, the acromegalic group presented postural deviations in lateral views in the vertical alignment of the trunk (P=0.001 for the right side and P=0.021 for the left), the hip angle (P=0001 for the right side and P=0.016 for the left side) and horizontal alignment of the pelvis (P=0.017 for the right and P<0.001 for the left side). Compared with healthy subjects, the acromegalic patients presented displacement of the centre of pressure in both the anterior-posterior direction and the medial-lateral direction in both evaluated tasks. We observed significant correlations between balance measures and the following posture evaluation variables: distance between the lower limbs, horizontal alignment of the head and vertical alignment of the head. Our results suggest that posture and balance need to be evaluated for acromegalic patients in clinical practice, as there are significant postural imbalances and deviations in these patients.

Neuropsychological and physiological correlates of fatigue following traumatic brain injury

BACKGROUND

Fatigue is a common and debilitating phenomenon experienced by individuals with traumatic brain injury (TBI) that can negatively influence rate and extent of functional recovery by reducing participation in brain injury rehabilitation services and increasing maladaptive lifestyle practices. The underlying mechanisms of TBI-related fatigue are not entirely understood and focused research on symptom reduction or prevention is limited.

REVIEW

The current review of the literature suggests that the aetiology of TBI-related fatigue can be viewed as a multifactorial and complex model impacting physiological systems (i.e. endocrine, skeletal muscle and cardiorespiratory) that can be directly or indirectly influenced by neuropsychological correlates including cognitive and psychological impairment. Distinguishing central from peripheral fatigue is helpful in this regard. Potential therapeutic strategies and pharmacological agents to help alleviate fatigue in this patient population are discussed.

Action of GH on skeletal muscle function: molecular and metabolic mechanisms

Skeletal muscle is a target tissue of GH. Based on its anabolic properties, it is widely accepted that GH enhances muscle performance in sports and muscle function in the elderly. This paper critically reviews information on the effects of GH on muscle function covering structure, protein metabolism, the role of IGF1 mediation, bioenergetics and performance drawn from molecular, cellular and physiological studies on animals and humans. GH increases muscle strength by enhancing muscle mass without affecting contractile force or fibre composition type. GH stimulates whole-body protein accretion with protein synthesis occurring in muscular and extra-muscular sites. The energy required to power muscle function is derived from a continuum of anaerobic and aerobic sources. Molecular and functional studies provide evidence that GH stimulates the anaerobic and suppresses the aerobic energy system, in turn affecting power-based functional measures in a time-dependent manner. GH exerts complex multi-system effects on skeletal muscle function in part mediated by the IGF system.