Growth hormone in the aging male

Associations between temporal eating patterns and body composition in young adults: a cross-sectional study

PURPOSE

The aim of this study was to examine the associations between body composition and temporal eating patterns, including time of first eating occasion, time of last eating occasion, eating window, and eating jet lag (the variability in meal timing between weekdays and weekends).

METHODS

A total of 131 participants were included in the study. Temporal eating pattern information was collected through consecutive 7-day eat timing questionnaires and photographic food records. Body composition was assessed by bioelectrical impedance analysis. Multiple linear regression models were used to evaluate the relationships of temporal eating patterns with body composition, and age was adjusted. Eating midpoint was additionally adjusted in the analysis of eating window.

RESULTS

On weekdays, both later first eating occasion and last eating occasion were associated with lower lean mass, and longer eating window was associated with lower body fat percentage. On weekends, both later first eating occasion and last eating occasion were associated with lower lean mass, and longer eating window was associated with higher FFMI. Longer first eating occasion jet lag was associated with lower lean mass.

CONCLUSION

Our study suggested that earlier and more regular eating patterns may have a benefit on body composition.

[Unfavourable cardiovascular consequences of adult growth hormone deficiency]

The growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis plays a crucial role in maintaining the normal function of the cardiovascular system. Results of the last decades demonstrated that GH-IGF-1 takes part in regulating peripheral resistance and contributes to preserving physiological cardiac mass and left ventricular function. Vasculoprotective functions of the GH-IGF-1 axis are believed to counteract atherosclerosis. Unlike in childhood, when GH-deficiency results in growth retardation, GH deficiency does not cause specific symptoms in adults. Adult growth hormone deficiency (AGHD) is characterized by a clustering of cardiometabolic risk factors resulting in a clinical picture similar to the metabolic syndrome. Besides visceral obesity, dyslipidemia and insulin resistance, novel cardiovascular risk factors, such as chronic low-grade inflammation, oxidative stress and prothrombotic state have also been reported in AGHD and may contribute to the increased cardiometabolic risk. Based on a growing body of evidence, long-term GH-replacement improves lipid profile significantly and has a favorable impact on body composition, endothelial function, left ventricular mass as well as the novel, non-traditional cardiometabolic risk factors. Increased mortality associated with the disease is now considered to be multicausal and as such cannot be solely attributed to the GH-deficiency. The etiology of GH-deficiency, treatment of the underlying pathology as well as the inadequate treatment of coexisting hormonal deficiencies might also be responsible for the increased mortality. Nevertheless, in hypopituitarism, adequate replacement therapy including GH-substitution may result in a mortality that is comparable to the general population. Orv Hetil. 2023; 164(41): 1616-1627.

A Comprehensive Review of Pathological Mechanisms and Natural Dietary Ingredients for the Management and Prevention of Sarcopenia

Sarcopenia is characterized by an age-related loss of skeletal muscle mass and function and has been recognized as a clinical disease by the World Health Organization since 2016. Substantial evidence has suggested that dietary modification can be a feasible tool to combat sarcopenia. Among various natural dietary ingredients, the present study focused on botanical and marine extracts, phytochemicals, and probiotics. Aims of this review were (1) to provide basic concepts including the definition, diagnosis, prevalence, and adverse effects of sarcopenia, (2) to describe possible pathological mechanisms including protein homeostasis imbalance, inflammation, mitochondrial dysfunction, and satellite cells dysfunction, and (3) to analyze recent experimental studies reporting potential biological functions against sarcopenia. A recent literature review for dietary ingredients demonstrated that protein homeostasis is maintained via an increase in the PI3K/Akt pathway and/or a decrease in the ubiquitin-proteasome system. Regulation of inflammation has primarily targeted inhibition of NF-κB signaling. Elevated Pgc-1α or Pax7 expression reverses mitochondrial or satellite cell dysfunction. This review provides the current knowledge on dietary components with the potential to assist sarcopenia prevention and/or treatment. Further in-depth studies are required to elucidate the role of and develop various dietary materials for healthier aging, particularly concerning muscle health.

Six-Month Synbio® Administration Affects Nutritional and Inflammatory Parameters of Older Adults Included in the PROBIOSENIOR Project

The physiological changes associated with ageing contribute to the incidence of diseases, morbidity, and mortality. For modern society, it is essential to find solutions to improve elderly people's health and quality of life. Among promising strategies, the PROBIOSENIOR project proposed a daily six-month supplementation with new probiotic functional foods and nutraceuticals. The aim of this work was to evaluate the modulating effects of the probiotic diet on inflammatory markers and nutritional status. Ninety-seven elderly volunteers were randomly assigned to either a placebo-diet group or a probiotic-diet group (SYNBIO^®). Faeces, urine, and blood samples were collected before and after the supplementation to determine serum cytokines, biogenic amines, and inflammation markers. Comparing the results obtained before and after the intervention, probiotic supplementations significantly decreased the TNF-α circulating levels and significantly increased those of IGF-1. Biogenic-amine levels showed high variability, with significant variation only for histamine that decreased after the probiotic supplementation. The supplementation influenced the serum concentration of some crucial cytokines (IL-6, IL-8, and MIP-1α) that significantly decreased in the probiotic group. In addition, the Mini Nutritional Assessment questionnaire revealed that the probiotic-supplemented group had a significant improvement in nutritional status. In conclusion, the PROBIOSENIOR project demonstrated how SYNBIO^® supplementation may positively influence some nutritional and inflammatory parameters in the elderly.

The multiple roles of GH in neural ageing and injury

Advanced age is typically associated with a decrease in cognitive function including impairment in the formation and retention of new memories. The hippocampus is critical for learning and memory, especially spatial learning, and is particularly affected by ageing. With advanced age, multiple neural components can be detrimentally affected including a reduction in the number of neural stem and precursor cells, a decrease in the formation of adult born neurons (neurogenesis), and deficits in neural circuitry, all of which ultimately contribute to impaired cognitive function. Importantly, physical exercise has been shown to ameliorate many of these impairments and is able to improve learning and memory. Relevantly, growth hormone (GH) is an important protein hormone that decreases with ageing and increases following physical exercise. Originally described due to its role in longitudinal growth, GH has now been identified to play several additional key roles, especially in relation to the brain. Indeed, the regular decrease in GH levels following puberty is one of the most well documented components of neuroendocrine ageing. Growth hormone deficiency (GHD) has been described to have adverse effects on brain function, which can be ameliorated via GH replacement therapy. Physical exercise has been shown to increase circulating GH levels. Furthermore, we recently demonstrated the increase in exercise-mediated GH is critical for improved cognitive function in the aged mouse. Here we examine the multiple roles that GH plays, particularly in the aged brain and following trauma, irradiation and stroke, and how increasing GH levels can ameliorate deficits in cognition.

The Role of Sarcopenia in Heart Failure with Depression

Heart failure (HF) and depression are both major medical health issues in our society. Currently, an increasing number of studies demonstrate an association between HF and depression. The prevalence of depression is higher in patients with HF, and depression also increases the incidence of HF. Currently, depression has been listed as a major risk factor for heart disease. Patients with HF and comorbid depression have significantly higher rates of hospitalization and mortality, and clinical symptoms manifest as decreased activity tolerance and decreased muscle mass. Enhancement of the muscle function improves the prognosis of patients with HF and depression. Sarcopenia is defined as age-related loss of skeletal muscle mass plus loss of muscle strength and/or reduced physical performance, and its pathogenesis involves malnutrition, physical inactivity, endocrine disorders and chronic inflammation, which are also involved in the pathogenesis of HF with comorbid depression. Therefore, it would be intriguing to explore the linkage between HF, depression and sarcopenia. This review presents an overview of HF with comorbid depression and sarcopenia, elucidates the mechanisms involved in these disorders, and finally summarizes the treatment strategies of HF with comorbid depression and sarcopenia.

Hormonal and metabolic responses of older adults to resistance training in normobaric hypoxia

PURPOSE

In young adults, the hormonal responses to resistance exercise are amplified by normobaric hypoxia. Hormone concentrations and metabolism are typically dysregulated with age, yet the impact of hypoxia on these responses to resistance exercise are uncharacterised. Therefore, this study aimed to characterise the acute and chronic hormonal and metabolic responses of older adults to resistance training in normobaric hypoxia.

METHODS

Adults aged 60-75 years completed 8 weeks of resistance training in either normoxia (20.9% O₂; n = 10) or normobaric hypoxia (14.4% O₂, n = 10) twice weekly at 70% of their predicted 1-repetition maximum. Growth hormone, glucose, lactate, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), cortisol, total testosterone, adrenaline, noradrenaline and dopamine were quantified at pre- and post-training, and in the 60 min following the first training session (untrained state) and the last training session (trained state).

RESULTS

Eight weeks of training in hypoxia did not affect the resting levels of the hormones or physiological factors measured. However, hypoxia significantly blunted the acute growth hormone response in the 15 min following the last training session at week eight (43.87% lower in the hypoxic group; p = 0.017). This novel and unexpected finding requires further investigation. All other hormones were unaffected acutely by hypoxia in the 60 min following the first and the last training session.

CONCLUSION

Chronic resistance training in normobaric hypoxia supresses the growth hormone response to exercise in older adults. All other hormones and metabolic markers were unaffected both acutely and chronically by hypoxia.

Role of MicroRNAs and Long Non-Coding RNAs in Sarcopenia

Sarcopenia is an age-related pathological process characterized by loss of muscle mass and function, which consequently affects the quality of life of the elderly. There is growing evidence that non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), play a key role in skeletal muscle physiology. Alterations in the expression levels of miRNAs and lncRNAs contribute to muscle atrophy and sarcopenia by regulating various signaling pathways. This review summarizes the recent findings regarding non-coding RNAs associated with sarcopenia and provides an overview of sarcopenia pathogenesis promoted by multiple non-coding RNA-mediated signaling pathways. In addition, we discuss the impact of exercise on the expression patterns of non-coding RNAs involved in sarcopenia. Identifying non-coding RNAs associated with sarcopenia and understanding the molecular mechanisms that regulate skeletal muscle dysfunction during aging will provide new insights to develop potential treatment strategies.

The poorly conducted orchestra of steroid hormones, oxidative stress and inflammation in frailty needs a maestro: Regular physical exercise

This review outlines the various factors associated with unhealthy aging which includes becoming frail and dependent. With many people not engaging in recommended exercise, facilitators and barriers to engage with exercise must be investigated to promote exercise uptake and adherence over the lifespan for different demographics, including the old, less affluent, women, and those with different cultural-ethnic backgrounds. Governmental and locally funded public health messages and environmental facilitation (gyms, parks etc.) can play an important role. Studies have shown that exercise can act as a conductor to balance oxidative stress, immune and endocrine functions together to promote healthy aging and reduce the risk for age-related morbidities, such as cardiovascular disease and atherosclerosis, and promote cognition and mood over the lifespan. Like a classic symphony orchestra, consisting of four groups of related musical instruments - the woodwinds, brass, percussion, and strings - the aging process should also perform in harmony, with compassion, avoiding the aggrandizement of any of its individual parts during the presentation. This review discusses the wide variety of molecular, cellular and endocrine mechanisms (focusing on the steroid balance) underlying this process and their interrelationships.

The involvement of Sestrin2 in the effect of IGF-I and leucine on mTROC1 activity in C2C12 and L6 myocytes

OBJECTIVE

IGF-I and branched-chain amino acids have been reported to promote muscle hypertrophy via the stimulation of protein synthesis. Sestrin2, the function of which is regulated by leucine, has been reported to attenuate the activity of the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) that stimulates protein synthesis. The objective of this study was to examine whether IGF-I modulates Sestrin2 abundance and to clarify the involvement of Sestrin2 in the effect of IGF-I and leucine on mTROC1.

DESIGN

C2C12 and L6 myocytes were stimulated by leucine (1 mM) with or without pretreatment with IGF-I (100 ng/mL). Phosphorylation of p70 S6 kinase (S6K) and 4E-binding protein 1 (4E-BP1), both of which are targets of the mTORC1, was examined by western blotting. Effects of Sestrin2 small interfering RNA (siRNA) on the actions of leucine and IGF-I were examined. Sestrin2 mRNA and protein levels were also determined after Sestrin2 siRNA.

RESULTS

Leucine increased the phosphorylation of S6K and 4E-BP1 in a dose-dependent manner. Pretreatment with IGF-I for 5 h further increased the stimulatory effect of leucine on the phosphorylation of S6K and 4E-BP1 in C2C12 cells. IGF-I increased Sestrin2 protein and messenger RNA levels. Sestrin2 siRNA increased or tended to increase basal phosphorylation of 4E-BP1 and decreased the leucine-induced phosphorylation in C2C12 and L6 cells, in particular after IGF-I treatment, suggesting the involvement of Sestrin2 in the action of leucine and IGF-I. The net increase in leucine-induced 4E-BP1 phosphorylation appeared to be attenuated by Sestrin2 siRNA. Likewise, Sestrin2 siRNA attenuated leucine-induced S6K phosphorylation in L6 cells. However, Sestrin2 siRNA did not influence leucine-induced S6K phosphorylation in C2C12 cells.

CONCLUSIONS

IGF-I and leucine cooperatively increased mTORC1 activity in C2C12 cells. IGF-I increased Sestrin2. Sestrin2 siRNA experiments showed that Sestrin2 was involved in the effect of leucine and IGF-I on mTORC1 activity in C2C12 and L6 cells, and suggested that increased Sestrin2 by IGF-I pretreatment might play a role in enhancing the effect of leucine on mTORC1.

Higher levels of physical activity buffered the negative effect of pain severity on physical frailty in older Latinx adults

This cross-sectional study examined whether and to what extent physical activity (PA) mediated the effect of chronic pain on physical frailty in a sample of predominantly older Latinx adults. Study participants were 118 community-dwelling older adults in southwest United States. Physical frailty was measured by a summary score of physical function tests. Pain severity and pain interference were measured by the Brief Pain Inventory. PA levels were defined as meeting the PA recommendation by 7-day accelerometry. Pain outcomes and PA were associated with physical frailty, respectively. Hierarchical regression analysis revealed that PA mediated the relationship between pain severity and physical frailty. However, no mediation effect of PA was found in the relationship between pain interference and physical frailty scores. Higher levels of PA buffered the negative effect of pain severity on physical frailty. Future studies should pay attention to PA promotion to prevent the negative consequences of frailty in older minority adults.

Role of hormones in sarcopenia

Aging involves numerous changes in body composition that include a decrease in skeletal muscle mass. The gradual reduction in muscle mass is associated with a simultaneous decrease in muscle strength, which leads to reduced mobility, fragility and loss of independence. This process called sarcopenia is secondary to several factors such as sedentary lifestyle, inadequate nutrition, chronic inflammatory state and neurological alterations. However, the endocrine changes associated with aging seem to be of special importance in the development of sarcopenia. On one hand, advancing age is associated with a decreased secretion of the main hormones that stimulate skeletal muscle mass and function (growth hormone, insulin-like growth factor 1 (IGFI), testosterone and estradiol). On the other hand, the alteration of the IGF-I signaling along with decreased insulin sensitivity also have an important impact on myogenesis. Other hormones that decline with aging such as the adrenal-derived dehydroepiandrosterone, thyroid hormones and vitamin D seem to also be involved in sarcopenia. Adipokines released by adipose tissue show important changes during aging and can affect muscle physiology and metabolism. In addition, catabolic hormones such as cortisol and angiotensin II can accelerate aged-induced muscle atrophy, as they are involved in muscle wasting and their levels increase with age. The role played by all of these hormones and the possible use of some of them as therapeutic tools for treating sarcopenia will be discussed.

Clinical relevance of insulin-like growth factor-1 to cardiovascular risk markers

OBJECTIVE

Insulin-like growth factor-1 (IGF-1) is an anabolic hormone, the levels of which decline with age. The present study aimed to determine the impact of age-related declines in serum IGF-1 levels on various physiological processes.

DESIGN

We retrospectively reviewed the medical records of patients whose serum IGF-1 levels were estimated in our department, and assessed the relationships between serum IGF-1 levels and various physiological parameters.

RESULTS

A total of 427 patients with a mean (± standard deviation) age of 52.8 (± 17.1) years were included in the analysis. The levels of serum IGF-1 showed significant positive correlation with those of hemoglobin and hematocrit, and negative correlation with the presence of inflammatory and fibrin-related markers including C-reactive protein (CRP) and procalcitonin (PCT), and D-dimer and fibrin degradation products (FDP). These tendencies persisted after exclusion of patients with pituitary disease.

CONCLUSIONS

In this study population of diverse diseases and backgrounds, a decline in serum IGF-1 levels with age was associated with an increase in inflammatory and fibrin-related markers. This may explain the correlation between low serum IGF-1 levels and an increased risk of cardiovascular events. Our findings suggest that serum IGF-1 is a clinically relevant marker of cardiovascular risk, particularly in males.

Quercetin 3-O-malonylglucoside in the leaves of mulberry (Morus alba) is a functional analog of ghrelin

Mulberry (Morus alba) leaf is traditionally consumed as a functional tea with remedial effects, such as preventing aging-related diseases. Two similar compounds, quercetin 3-O-malonylglucoside, and kaempferol 3-O-malonylglucoside, were detected in mulberry leaves and found to be structural recombinant composites of teaghrelin and emoghrelin, two classes of non-peptidyl compounds functionally identified as analogs of ghrelin. Molecular modeling showed that these two mulberry compounds were able to enter and interact with the ghrelin receptor and theoretical calculation revealed that they were similar to emoghrelin but slightly weaker than teaghrelin in terms of interaction with the receptor. The relatively abundant compound, quercetin 3-O-malonylglucoside was subjected to a bioactivity assay, and the result confirmed that it was able to increase the growth hormone secretion of rat anterior pituitary cells. It seems that quercetin 3-O-malonylglucoside is also a functional analog of ghrelin and presumably a key ingredient for the anti-aging activity of mulberry leaves. PRACTICAL APPLICATIONS: According to this study, quercetin 3-O-malonylglucoside and kaempferol 3-O-malonylglucoside are suggested to serve as active ingredients in tea products prepared from mulberry leaves. Contents of these two compounds might be used as key factors for breeding or screening mulberry varieties for commercial cultivation. Moreover, water extract of mulberry leaves containing these compounds can be used as an adequate supplement for functional food.

Manipulating Cellular Energetics to Slow Aging of Tissues and Organs

Up to now numerous studies in the field of gerontology have been published. Nevertheless, a well-known food restriction remains the most reliable and efficient way of lifespan extension. Physical activity is also a well-documented anti-aging intervention being especially efficient in slowing down the age-associated decline of skeletal muscle mass. In this review we focus on the molecular mechanisms of the effect of physical exercise on muscle tissues. We also discuss the possibilities of pharmacological extension of this effect to the rest of the tissues. During the exercise, the level of ATP decreases triggering activation of AMP-dependent protein kinase (AMPK). This kinase stimulates antioxidant potential of the cells and their mitochondrial respiratory capacity. The exercise also induces mild oxidative stress, which, in turn, mediates the stimulation via hormetic response. Furthermore, during the exercise cells generate activators of mammalian target of rapamycin (mTOR). The intracellular ATP level increases during the rest periods between exercises thus promoting mTOR activation. Therefore, regular exercise intermittently activates anti-oxidant defenses and mitochondrial biogenesis (via AMPK and the hormetic response) of the muscle tissue, as well as its proliferative potential (via mTOR), which, in turn, impedes the age-dependent muscle atrophy. Thus, the intermittent treatment with activators of (i) AMPK combined with the inducers of hormetic response and of (ii) mTOR might partly mimic the effects of physical exercise. Importantly, pharmacological activation of AMPK takes place in the absence of ATP level decrease. The use of uncouplers of respiration and oxidative phosphorylation at the phase of AMPK activation could also prevent negative consequences of the cellular hyper-energization. It is believed that the decline of both antioxidant and proliferative potentials of the cells causes the age-dependent decline of multiple tissues, rather than only the muscular one. We argue that the approach above is applicable for the majority of tissues in an organism.

Association between sarcopenia and levels of growth hormone and insulin-like growth factor-1 in the elderly

Background

Age-related sarcopenia is a serious global health issue in elderly individuals and for the community as it induces disability and significant economic burden. The purpose of the study is to understand the factors associated with sarcopenia and the role of growth hormone (GH) and insulin-like growth factor (IGF-1) in the occurrence of sarcopenia.

Methods

Elderly patients (n = 3276) were included in this cross-sectional study. Survey and measurement of body composition (bioelectrical impedance), grip strength, and step speed were performed according to the Asian Working Group on Sarcopenia (AWGS) diagnostic criteria. Hematological and hormonal indicators were compared between patients with and without sarcopenia in order to identify the associated factors.

Results

There were significant differences in the demographic parameters between the sarcopenia and non-sarcopenia groups (all P < 0.05). There were significant differences between the two groups regarding the blood levels of GH, IGF-1, testosterone (T), and mechanical growth factor (MGF) (all P < 0.001). Correlation analyses showed that the appendicular skeletal muscle mass (ASMI) was positively associated with gender and BMI, and with GH, T, IGF-1, MGF, BUN, Cr, and Hb levels, but negatively associated with HDL-C (all P < 0.05). Logistic multivariable regression analysis showed that IGF-1, MGF, BMI, and gender were independently associated with appendicular skeletal muscle mass (ASMI) (all P < 0.05).

Conclusions

GH and IGF-1 are associated with sarcopenia in the elderly. IGF-1 and MGF are independently associated with the reduction of skeletal muscle mass, along with BMI and gender.

Mutations in growth hormone gene affect stability of protein structure leading to reduced growth, reproduction, and milk production in crossbred cattle-an insight

The GH has a multifaceted role in growth, reproduction, and milk production. Nonsynonymous mutations identified as L153V were observed from GH1 (L) to GH2 (V) with higher genotypic frequency for GH1 being 0.87. GH2 (V) allele was identified as a rare allele and the population followed Hardy-Weinberg equilibrium. LL homozygote variant had significantly better growth, reproduction, and expected milk production at different ages in crossbred (CB) males. Reports are scanty explaining the molecular mechanism of how individuals with LV genotype were phenotypically inferior to that of wild-type LL. In the present study, it was explored that GH peptide with LV heterozygotes of GH gene, were observed to have reduced structural stability thermodynamically and thus functionally leads to reduced economic traits in CB animals. The fact was first time reported and confirmed through genomic analysis, bioinformatics, and later confirmed through immunohistochemistry. Differential expression analysis of the GH gene with respect to other genes in the hypothalamus-pituitary growth axis of CB cattle was also studied to have a complete insight of the GH gene.

A high-fat diet reverses metabolic disorders and premature aging by modulating insulin and IGF1 signaling in SIRT6 knockout mice

Mammalian sirtuin 6 (SIRT6) is involved in the regulation of many essential processes, especially metabolic homeostasis. SIRT6 knockout mice undergo premature aging and die at age ~4 weeks. Severe glycometabolic disorders have been found in SIRT6 knockout mice, and whether a dietary intervention can rescue SIRT6 knockout mice remains unknown. In our study, we found that at the same calorie intake, a high‐fat diet dramatically increased the lifespan of SIRT6 knockout mice to 26 weeks (males) and 37 weeks (females), reversed multi‐organ atrophy, and reduced body weight, hypoglycemia, and premature aging. Furthermore, the high‐fat diet partially but significantly normalized the global gene expression profile in SIRT6 knockout mice. Regarding the mechanism, excessive glucose uptake and glycolysis induced by the SIRT6 deficiency were attenuated in skeletal muscle through inhibition of insulin and IGF1 signaling by the high‐fat diet. Similarly, fatty acids but not ketone bodies inhibited glucose uptake, glycolysis, and senescence in SIRT6 knockout fibroblasts, whereas PI3K inhibition antagonized the effects of a high‐fatty‐acid medium in vitro. Overall, the high‐fat diet dramatically reverses numerous consequences of SIRT6 deficiency through modulation of insulin and IGF1 signaling, providing a new basis for elucidation of SIRT6 and fatty‐acid functions and supporting novel therapeutic approaches against metabolic disorders and aging‐related diseases.

Prevalence of growth hormone deficiency in middle-age adults recovering from stroke

Objective: The prevalence of chronic growth hormone deficiency (GHD) and its association with other hormonal deficiencies was determined in middle-aged patients post-stroke with and without consideration of body mass index (BMI).Methods: Clinical records were reviewed to determine pituitary function at least 3 months post-stroke. Patients with a history of endocrine anomalies were excluded. GHD was determined by utilizing standard peak GH cutoffs following the glucagon stimulation test. A secondary analysis was conducted with stricter BMI-adjusted cutoffs. The accuracy of IGF-1 in predicting GHD was also examined.Results: GHD was diagnosed in 54% of patients (≥5.0 μg/L), with 32% falling into the severe (≤3 μg/L) category. Patients with GHD had lower levels of FSH, T3, LH, and SHBG. Analyzes of BMI-adjusted GH levels, revealed that 14% of patients were GHD. These patients had higher prolactin. IGF-1 values were not predictive of GHD. Latency to be admitted to post-acute rehabilitation was greater in patients with GHD.Conclusions: Evidence suggests patients with stroke may be at risk for developing GHD. GHD was associated with decreased levels of other hormones. Co-morbidities for stroke and neuroendocrine dysfunction overlap and may have implications for recovery following stroke.

Risk factors for premature aging in childhood cancer survivors

Over the last decades, the overall survival rate for childhood cancer has increased from 20% to 80%, which is the result of advances in treatment. Nevertheless, most data from the international registers of childhood cancer survivors (CCS) stress that this population of patients is at high risk for late sequelae and their biological aging starts earlier in life. Anticancer therapy (chemotherapy, radiotherapy, surgery, immunotherapy) affects the intracellular processes leading to the chronic deterioration of organ function and premature senescence. The present review focuses on the late effects of anticancer treatment on various human organs that may lead to premature aging.

The Effect of Exercise on Glucoregulatory Hormones: A Countermeasure to Human Aging: Insights from a Comprehensive Review of the Literature

Hormones are secreted in a circadian rhythm, but also follow larger-scale timetables, such as monthly (hormones of the menstrual cycle), seasonal (i.e., winter, summer), and, ultimately, lifespan-related patterns. Several contexts modulate their secretion, such as genetics, lifestyle, environment, diet, and exercise. They play significant roles in human physiology, influencing growth of muscle, bone, and regulating metabolism. Exercise training alters hormone secretion, depending on the frequency, duration, intensity, and mode of training which has an impact on the magnitude of the secretion. However, there remains ambiguity over the effects of exercise training on certain hormones such as glucoregulatory hormones in aging adults. With advancing age, there are many alterations with the endocrine system, which may ultimately alter human physiology. Some recent studies have reported an anti-aging effect of exercise training on the endocrine system and especially cortisol, growth hormone and insulin. As such, this review examines the effects of endurance, interval, resistance and combined training on hormones (i.e., at rest and after) exercise in older individuals. We summarize the influence of age on glucoregulatory hormones, the influence of exercise training, and where possible, examine masters' athletes' endocrinological profile.

MECHANISMS OF ENDOCRINE DISEASE: Sarcopenia in endocrine and non-endocrine disorders

Objective This paper reviews the main mechanisms, diagnostic criteria, treatment options and available data on sarcopenia in endocrine and non-endocrine disorders. The literature notes the presence of sarcopenia as a comorbid condition or a complication of another clinical situation and not a disease that only affects elderly patients. Method We performed a literature review, focusing on the following: mechanisms related to sarcopenia in elderly patients, and sarcopenia as it presents in the context of chronic and endocrine diseases; diagnostic tools and methods; aspects of sarcopenia and treatment options specific to chronic diseases and endocrine disorders respectively. Results Sarcopenia in chronic and endocrine disorders shares many mechanisms with sarcopenia affecting elderly patients, but certain diseases can have a predominant aspect that leads to sarcopenia. The prevalence of sarcopenia varies, depending on different diagnostic criteria, from around 12 to 60% in chronic illnesses and 15 to 90% in endocrine disorders. The interplay between sarcopenia, chronic diseases and elderly patients requires further study, to clarify the impact of each, in terms of prognosis and mortality. Conclusion Awareness of the presentation of sarcopenia in the context of other diseases and ages (and not just the elderly) is fundamental to ensure that preventive measures can be deployed.

Echinacoside Isolated from Cistanche tubulosa Putatively Stimulates Growth Hormone Secretion via Activation of the Ghrelin Receptor

Cistanche species, the ginseng of the desert, has been recorded to possess many biological activities in traditional Chinese pharmacopoeia and has been used as an anti-aging medicine. Three phenylethanoid glycosides—echinacoside, tubuloside A, and acteoside—were detected in the water extract of Cistanche tubulosa (Schenk) R. Wight and the major constituent, echinacoside, was further purified. Echinacoside of a concentration higher than 10⁻⁶ M displayed significant activity to stimulate growth hormone secretion of rat pituitary cells. Similar to growth hormone-releasing hormone-6, a synthetic analog of ghrelin, the stimulation of growth hormone secretion by echinacoside was inhibited by [D-Arg¹, D-Phe⁵, D-Trp^7,9, Leu¹¹]-substance P, an inverse agonist of the ghrelin receptor. Molecular modeling showed that all the three phenylethanoid glycosides adequately interacted with the binding pocket of the ghrelin receptor, and echinacoside displayed a slightly better interaction with the receptor than tubuloside A and acteoside. The results suggest that phenylethanoid glycosides, particularly echinacoside, are active constituents putatively responsible for the anti-aging effects of C. tubulosa and may be considered to develop as non-peptidyl analogues of ghrelin.

Elemental Analysis of Aging Human Pituitary Glands Implicates Mercury as a Contributor to the Somatopause

Background: Growth hormone levels often decline on aging, and this "somatopause" is associated with muscle and bone loss, visceral adiposity and impaired cardiovascular function. Mercury has been detected in human pituitary glands, so to see if mercury could play a part in the somatopause we measured the proportion of people at different ages who had mercury in their anterior pituitary cells. Materials and methods: Paraffin sections of pituitary glands taken at autopsy from 94 people between the ages of 2 and 99 years were stained for inorganic mercury using autometallography. Pituitary mercury content was classified as none, low (<30% of cells) or high (>30% of cells) in increasing two-decade age groups. Autometallography combined with immunohistochemistry determined which hormone-producing cells contained mercury. Laser ablation-inductively coupled plasma-mass spectrometry was used to confirm the presence of mercury. Results: The proportion of people with low-content pituitary mercury remained between 33 and 42% at all ages. The proportion of people with high-content mercury increased with increasing age, from 0% of people in the 2-20 year group to a peak of 50% of people in the 61-80 years group, followed by a fall to 35% of people in the 81-99 years group. Mercury, when present, was found always in somatotrophs, occasionally in corticotrophs, rarely in thyrotrophs and gonadotrophs, and never in lactotrophs. Laser ablation-inductively coupled plasma-mass spectrometry detected mercury in regions of pituitaries that stained with autometallography. Conclusions: The proportion of people with mercury in their anterior pituitary cells, mostly somatotrophs, increases with aging, suggesting that mercury toxicity could be one factor contributing to the decline in growth hormone levels found in advancing age.

A useful model to compare human and mouse growth hormone gene chromosomal structure, expression and regulation, and immune tolerance of human growth hormone analogues

Human (h) pituitary growth hormone (GH) is both physiologically and clinically important. GH reaches its highest circulatory levels in puberty, where it contributes to energy homeostasis and somatogenic growth. GH also helps to maintain tissues and organs and, thus, health and homeostasis. A reduction in the rate of hGH production begins in middle age but if GH insufficiency occurs this may result in tissue degenerative and metabolic diseases. As a consequence, hGH is prescribed under conditions of GH deficiency and, because of its lipolytic activity, stimulation of hGH release has also been used to treat obesity. However, studies of normal GH production and particularly synthesis versus secretion are not feasible in humans as they require sampling normal pituitaries from living subjects. Furthermore, human (or primate) GH structure and, as such, regulation and potential function, is distinct from non-primate rodent GH. As a result, most information about hGH regulation comes from measurements of secreted levels of GH in humans. Thus, partially humanized hGH transgenic mice, generated containing fragments of human chromosome 17 that include the intact hGH gene locus and many thousands of flanking base pairs as well as the endogenous mouse (m) GH gene provide a potentially useful model. Here we review this mouse model in terms of its ability to allow comparison of hGH versus mGH gene expression, and specifically: (i) GH locus structure as well as regulated and rhythmic expression; (ii) their ability to model a clinical assessment of hGH production in response to overeating and hyperinsulinemia as well as a possible effect of exercise, and (iii) their hGH-related immune tolerance and thus potential for testing hGH-related analogue immunogenicity.

Comparison of performing 12 weeks' resistance training before, after and/or in between aerobic exercise on the hormonal status of aged women: a randomized controlled trial

Background Physiological aging can now be considered as a multi-factorial process that is associated with anatomical and signaling changes associated with endocrine function. The purpose of this study was to investigate the comparison of performing 12 weeks' resistance training before, after and/or in between aerobic exercise on the hormonal status of aged women. Materials and methods Forty healthy aged women (age: 67.35 ± 1.40 years) were randomly divided into three training groups and a control group: resistance followed by endurance training (ER, n = 12), endurance training followed by resistance training (RE, n = 12, interval resistance-endurance (RE) training (INT, n = 12) and a control (Con, n = 12) groups. The training program was done over 12 weeks, 3 times per week. Endurance training was performed on a cycle ergometer (intensity: 60-90% maximum heart rate) and resistance training involved selected resistance exercises (intensity: 40-75 one-repetition maximum, 8-18 repeats). All participants were evaluated before and after the training period. Results and conclusion The data showed that performing resistance training before, after and/or in between aerobic exercise did not influence the adaptive response of insulin like growth factor-1 (IGF-1) (p = 0.07), growth hormone (p = 0.35), cortisol (p = 0.20), insulin (p = 0.72), epinephrine (p = 0.83) and norepinephrine (p = 0.86) levels throughout the study. However, when comparing pre and post, no significant differences were shown following combined training within the SE, ES and INT groups for all variables (p < 0.05), except of IGF-1 within ES (p = 0.04) and SE (p = 0.02), and testosterone within ES (p = 0.007). In conclusion, combined training with RE order may be more effective than other orders for increasing anabolic status in aged women.

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.

Growth Hormone and Aging: Updated Review

Role of growth hormone (GH) in mammalian aging is actively explored in clinical, epidemiological, and experimental studies. The age-related decline in GH levels is variously interpreted as a symptom of neuroendocrine aging, as one of causes of altered body composition and other unwelcome symptoms of aging, or as a mechanism of natural protection from cancer and other chronic diseases. Absence of GH signals due to mutations affecting anterior pituitary development, GH secretion, or GH receptors produces an impressive extension of longevity in laboratory mice. Extension of healthspan in these animals and analysis of survival curves suggest that in the absence of GH, aging is slowed down or delayed. The corresponding endocrine syndromes in the human have no consistent impact on longevity, but are associated with remarkable protection from age-related disease. Moreover, survival to extremely old age has been associated with reduced somatotropic (GH and insulin-like growth factor-1) signaling in women and men. In both humans and mice, elevation of GH levels into the supranormal (pathological) range is associated with increased disease risks and reduced life expectancy likely representing acceleration of aging. The widely advertised potential of GH as an anti-aging agent attracted much interest. However, results obtained thus far have been disappointing with few documented benefits and many troublesome side effects. Possible utility of GH in the treatment of sarcopenia and frailty remains to be explored.

Mediators and Patterns of Muscle Loss in Chronic Systemic Inflammation

Besides its primary function in locomotion, skeletal muscle (SKM), which represents up to half of human's weight, also plays a fundamental homeostatic role. Through the secretion of soluble peptides, or myokines, SKM interacts with major organs involved in metabolic processes. In turn, metabolic cues from these organs are received by muscle cells, which adapt their response accordingly. This is done through an intricate intracellular signaling network characterized by the cross-talking between anabolic and catabolic pathways. A fine regulation of the network is required to protect the organism from an excessive energy expenditure. Systemic inflammation evokes a catabolic reaction in SKM known as sarcopenia. In turn this response comprises several mechanisms, which vary depending on the nature of the insult and its magnitude. In this regard, aging, chronic inflammatory systemic diseases, osteoarthritis and idiopathic inflammatory myopathies can lead to muscle loss. Interestingly, sarcopenia may persist despite remission of chronic inflammation, an issue which warrants further research. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) system stands as a major participant in muscle loss during systemic inflammation, while it is also a well-recognized orchestrator of muscle cell turnover. Herein we summarize current knowledge about models of sarcopenia, their triggers and major mediators and their effect on both protein and cell growth yields. Also, the dual action of the JAK/STAT pathway in muscle mass changes is discussed. We highlight the need to unravel the precise contribution of this system to sarcopenia in order to design targeted therapeutic strategies.

Somatopause, weaknesses of the therapeutic approaches and the cautious optimism based on experimental ageing studies with soy isoflavones

The pathological phenomenon of somatopause, noticeable in hypogonadal ageing subjects, is based on the growth hormone (GH) production and secretion decrease along with the fall in GH binding protein and insulin-like growth factor 1 (IGF-1) levels, causing different musculoskeletal, metabolic and mental issues. From the perspective of safety and efficacy, GH treatment is considered to be highly controversial, while some other therapeutic approaches (application of IGF-1, GH secretagogues, gonadal steroids, cholinesterase-inhibitors or various combinations) exhibit more or less pronounced weaknesses in this respect. Soy isoflavones, phytochemicals that have already demonstrated the health benefits in treated elderly, at least experimentally reveal their potential for the somatopausal symptoms remediation. Namely, genistein enhanced GHRH-stimulated cAMP accumulation and GH release in rat anterior pituitary cells; refreshed and stimulated the somatotropic system (hypothalamic nuclei and pituitary GH cells) function in a rat model of the mild andropause, and stimulated the GH output in ovariectomized ewes as well as the amplitude of GH pulses in the rams. Daidzein, on the other hand, increased body mass, trabecular bone mass and decreased bone turnover in the animal model of severe andropause, while both isoflavones demonstrated blood cholesterol-lowering effect in the same model. These data, which necessarily need to be preclinically and clinically filtered, hint some cautious optimism and call for further innovative designing of balanced soy isoflavone-based therapeutics.

The Role of IGF-1 Signaling in Skeletal Muscle Atrophy

Insulin-like growth factor 1 (IGF-1) is a key anabolic growth factor stimulating phosphatidylinositol 3-kinase (PI3K)/Akt signaling which is well known for regulating muscle hypertrophy. However, the role of IGF-1 in muscle atrophy is less clear. This review provides an overview of the mechanisms via which IGF-1 signaling is implicated in several conditions of muscle atrophy and via which mechanisms protein turnover is altered. IGF-1/PI3K/Akt signaling stimulates the rate of protein synthesis via p70S6Kinase and p90 ribosomal S6 kinase and negatively regulates protein degradation, predominantly by its inhibiting effect on proteasomal and lysosomal protein degradation. Caspase-dependent protein degradation is also attenuated by IGF/PI3K/Akt signaling, whereas evidence for an effect on calpain-dependent protein degradation is inconclusive. IGF-1/PI3K/Akt signaling reduces during denervation-, unloading-, and joint immobilization-induced muscle atrophy, whereas IGF-1/PI3K/Akt signaling seems unaltered during aging-associated muscle atrophy. During denervation and aging, IGF-1 overexpression or injection counteracts denervation- and aging-associated muscle atrophy, despite enhanced anabolic resistance with regard to IGF-1 signaling with aging. It remains unclear whether pharmacological stimulation of IGF-1/PI3K/Akt signaling attenuates immobilization- or unloading-induced muscle atrophy. Exploration of the possibilities to interfere with IGF-1/PI3K/Akt signaling reveals that microRNAs targeting IGF-1 signaling components are promising targets to counterbalance muscle atrophy. Overall, the findings summarized in this review show that in disuse conditions, but not with aging, IGF-1/PI3K/Akt signaling is attenuated and that in some conditions stimulation of this pathway may alleviate skeletal muscle atrophy.

Effect of intra-hippocampal injection of human recombinant growth hormone on synaptic plasticity in the nucleus basalis magnocellularis-lesioned aged rats

In this study, we proposed that administration of hippocampal growth hormone in ageing animals with growth hormone deficiency can compensate long-term potentiation and synaptic plasticity in nucleus basalis magnocellularis (NBM)-lesioned rats. Aged male Wistar rats were randomly divided into six groups (seven in each) of sham-operated healthy rats (Cont); NBM-lesioned rats (L); NBM-lesioned rats and intrahippocampal injection of growth hormone vehicle (L + Veh); NBM-lesioned and intrahippocampal injection of growth hormone (10, 20 and 40 µg.2 µl-1) (L + GH). In vivo electrophysiological recording techniques were used to characterize maintenance of long-term potentiation at distinct times (1, 2, 3, 24 and 48 hours) after high-frequency stimulation. The population spike was enhanced significantly for about 48 hours following tetanic stimulation in rats treated with a dose-dependent growth hormone compared to the vehicle group (p < 0.05), possibly through neuronal plasticity and neurogenesis in affected areas.

Can whole body vibration exercises affect growth hormone concentration? A systematic review

Whole body vibration (WBV) has been recognized as an effective alternative exercise modality to resistance exercise for its ability in enhancing force and power, generating capacity in skeletal muscle, increasing bone mass and improving cardiovascular function. Since the effect of WBV exercises on growth hormone (GH) levels has been never compared and discussed, the aim of this study was to review systematically the literature to verify the WBV effects on GH concentration. By using PubMed, Scopus and PEDRo databases with the keywords 'growth hormone' or GH and 'whole body vibration' or WBV, we found and analysed 12 papers (182 subjects recruited), verifying their level of evidence (National Health and Medical Research Council hierarchy of evidence) and the methodological quality (PEDRo scale). Although WBV induced GH responses in nine out of 12 publications, caution should be however taken when considering the results due to the markedly different methodologies among these publications.

Further Clinical Evidence for the Effect of IGF-1 on Hair Growth and Alopecia

Observations on the Laron syndrome originally offered the opportunity to explore the effect of insulin-like growth factor 1 (IGF-1) deficiency on human hair growth and differentiation. According to its expression in the dermal hair papilla, IGF-1 is likely involved in reciprocal signaling. It has been shown to affect follicular proliferation, tissue remodeling, and the hair growth cycle, as well as follicular differentiation, identifying IGF-1 signaling as an important mitogenic and morphogenetic regulator in hair follicle biology. Of all the cytokines or growth factors that have been postulated to play a role in hair follicles, ultimately IGF-1 is known to be regulated by androgens. Accordingly, dermal papillary cells from balding scalp follicles were found to secrete significantly less IGF-1 than their counterparts from nonbalding scalp follicles. Herein, hypotrichosis in primary growth hormone deficiency, and a lack of response of female and male androgenetic-type alopecia to treatment with topical minoxidil and oral finasteride in patients who had undergone surgical resection of the pituitary gland, provide further evidence for an effect of IGF-1 on hair growth and alopecia.

Nonandrogenic Anabolic Hormones Predict Risk of Frailty: European Male Ageing Study Prospective Data

CONTEXT

Low levels of nonandrogenic anabolic hormones have been linked with frailty, but evidence is conflicting and prospective data are largely lacking.

OBJECTIVE

To determine associations between nonandrogenic anabolic hormones and prospective changes in frailty status.

DESIGN/SETTING

A 4.3-year prospective observational study of community-dwelling men participating in the European Male Ageing Study.

PARTICIPANTS

Men (n = 3369) aged 40 to 79 years from eight European centers.

MAIN OUTCOME MEASURES

Frailty status was determined using frailty phenotype (FP; n = 2114) and frailty index (FI; n = 2444).

ANALYSIS

Regression models assessed relationships between baseline levels of insulinlike growth factor 1 (IGF-1), its binding protein 3 (IGFBP-3), dehydroepiandrosterone sulfate (DHEA-S), 25-hydroxyvitamin D (25OHD), and parathyroid hormone (PTH), with changes in frailty status (worsening or improving frailty).

RESULTS

The risk of worsening FP and FI decreased with 1 standard deviation higher IGF-1, IGFBP-3, and 25OHD in models adjusted for age, body mass index, center, and baseline frailty [IGF-1: odds ratio (OR) for worsening FP, 0.82 (0.73, 0.93), percentage change in FI, -3.7% (-6.0, -1.5); IGFBP-3: 0.84 (0.75, 0.95), -4.2% (-6.4, -2.0); 25OHD: 0.84 (0.75, 0.95); -4.4%, (-6.7, -2.0)]. Relationships between IGF-1 and FI were attenuated after adjusting for IGFBP-3. Higher DHEA-S was associated with a lower risk of worsening FP only in men >70 years old [OR, 0.57 (0.35, 0.92)]. PTH was unrelated to change in frailty status.

CONCLUSIONS

These longitudinal data confirm the associations between nonandrogenic anabolic hormones and the changes in frailty status. Interventional studies are needed to establish causality and determine therapeutic implications.

Molecular mechanisms underlying metabolic syndrome: the expanding role of the adipocyte

The metabolic syndrome (MetS) is defined as a cluster of 3 or more metabolic and cardiovascular risk factors and represents a serious problem for public health. Altered function of adipose tissue has a significant impact on whole-body metabolism and represents a key driver for the development of these metabolic derangements, collectively referred as to MetS. In particular, increased visceral and ectopic fat deposition play a major role in the development of insulin resistance and MetS. A large body of evidence demonstrates that aging and MetS share several metabolic alterations. Of importance, molecular pathways that regulate lifespan affect key processes of adipose tissue physiology, and transgenic mouse models with adipose-specific alterations in these pathways show derangements of adipose tissue and other metabolic features of MetS, which highlights a causal link between dysfunctional adipose tissue and deleterious effects on whole-body homeostasis. This review analyzes adipose tissue-specific dysfunctions, including metabolic alterations that are related to aging, that have a significant impact on the development of MetS.-Armani, A., Berry, A., Cirulli, F., Caprio, M. Molecular mechanisms underlying metabolic syndrome: the expanding role of the adipocyte.

SARCOPENIA: AN ENDOCRINE DISORDER?

Sarcopenia is defined as low muscle function (walking speed or grip strength) in the presence of low muscle mass. A simple screening test-the SARC-F-is available to identify persons with sarcopenia. The major endocrine causes of sarcopenia are diabetes mellitus and male hypogonadism. Other causes are decreased physical activity, loss of motor neuron units, weight loss, inflammatory cytokines, reduced blood flow to muscles, very low 25(OH) vitamin D levels, and decreased growth hormone and insulin-like growth factor 1. Treatment for sarcopenia includes resistance and aerobic exercise, leucine-enriched essential amino acids, and vitamin D. In hypogonadal males, testosterone improves muscle mass, strength, and function. Selective androgen receptor molecules and anti-myostatin activin II receptor molecules are under development as possible treatments for sarcopenia.

ABBREVIATIONS

COPD = chronic obstructive pulmonary disease DHEA = dehydroepiandrosterone IGF-1 = insulin-like growth factor 1 GH = growth hormone mTOR = mammalian target of rapamycin SARM = selective androgen receptor molecule.

l-Ornithine stimulates growth hormone release in a manner dependent on the ghrelin system

We found that intraduodenal administration of l-ornithine (l-Orn) stimulates growth hormone (GH) secretion in Wistar rats, and then investigated its mechanism. GH-releasing activity after intraduodenal administration of l-Orn was blocked by [d-Lys³]-GHRP-6, an antagonist of the ghrelin receptor; however, l-Orn (100 μM) has no affinity for the ghrelin receptor, suggesting that the GH-releasing activity of l-Orn is mediated via ghrelin release and activation of the ghrelin receptor. Intraduodenally administered l-Orn increased ghrelin mRNA expression in the duodenum but not in the stomach or hypothalamus. In addition, l-Orn-induced GH-releasing activity was inhibited by propranolol, an antagonist of β-adrenergic receptor, which is known to be coupled to ghrelin release. In conclusion, intraduodenally administered l-Orn stimulates GH secretion through the sympathetic nervous and ghrelin systems.

Muscle wasting and cachexia in heart failure: mechanisms and therapies

Body wasting is a serious complication that affects a large proportion of patients with heart failure. Muscle wasting, also known as sarcopenia, is the loss of muscle mass and strength, whereas cachexia describes loss of weight. After reaching guideline-recommended doses of heart failure therapies, the most promising approach to treating body wasting seems to be combined therapy that includes exercise, nutritional counselling, and drug treatment. Nutritional considerations include avoiding excessive salt and fluid intake, and replenishment of deficiencies in trace elements. Administration of omega-3 polyunsaturated fatty acids is beneficial in selected patients. High-calorific nutritional supplements can also be useful. The prescription of aerobic exercise training that provokes mild or moderate breathlessness has good scientific support. Drugs with potential benefit in the treatment of body wasting that have been tested in clinical studies in patients with heart failure include testosterone, ghrelin, recombinant human growth hormone, essential amino acids, and β₂-adrenergic receptor agonists. In this Review, we summarize the pathophysiological mechanisms of muscle wasting and cachexia in heart failure, and highlight the potential treatment strategies. We aim to provide clinicians with the relevant information on body wasting to understand and treat these conditions in patients with heart failure.

Effects of paternal obesity on growth and adiposity of male rat offspring

Emerging evidence suggests that paternal obesity plays an important role in offspring health. Our previous work using a rodent model of diet-induced paternal obesity showed that female offspring from high-fat diet (HFD)-fed fathers develop glucose intolerance due to impairment of pancreatic insulin secretion. Here, we focused on the health outcomes of male offspring from HFD-fed fathers. Male Sprague-Dawley rats (3 wk old) were fed control (CD-F0) or HFD (HFD-F0) for 12 wk before mating with control-fed females. Male offspring were fed control diets for up to 8 wk or 6 mo. Although male offspring from HFD-F0 did not develop any obvious glucose metabolism defects in this study, surprisingly, a growth deficit phenotype was observed from birth to 6 mo of age. Male offspring from HFD-F0 had reduced birth weight compared with CD-F0, followed by reduced postweaning growth from 9 wk of age. This resulted in 10% reduction in body weight at 6 mo with significantly smaller fat pads and skeletal muscles. Reduced circulating levels of growth hormone (GH) and IGF-I were detected at 8 wk and 6 mo, respectively. Expression of adipogenesis markers was decreased in adipose tissue of HFD-F0 offspring at 8 wk and 6 mo, and expression of growth markers was decreased in muscle of HFD-F0 offspring at 8 wk. We propose that the reduced GH secretion at 8 wk of age altered the growth of male offspring from HFD-F0, resulting in smaller animals from 9 wk to 6 mo of age. Furthermore, increased muscle triglyceride content and expression of lipogenic genes were observed in HFD-F0 offspring, potentially increasing their metabolic risk.

Ginkgoghrelins, unique acylated flavonoid diglycosides in Folium Ginkgo, stimulate growth hormone secretion via activation of the ghrelin receptor

ETHNOPHARMACOLOGICAL RELEVANCE

Folium Ginkgo, the dried leaf of Ginkgo biloba L. is a traditional Chinese medicine listed in the Pharmacopoeia of the People's Republic of China with several therapeutic effects, including prevention of aging. It is used as herbal medicine for the treatment of several aging-related diseases. The therapeutic effects of Folium Ginkgo on aging-related diseases are suspected to be similar to the anti-aging effects of growth hormone release induced by ghrelin.

MATERIALS AND METHODS

Candidate components responsible for the anti-aging effects via the ghrelin receptor-activated pathway were searched from the known compounds found in Folium Ginkgo. Two acylated flavonoid diglycosides, tentatively named ginkgoghrelins in this study, were selected and isolated from the methanol extract of Folium Ginkgo, and their chemical structures were confirmed by spectroscopic analysis. These two compounds were examined for their capability of stimulating growth hormone release of rat primary anterior pituitary cells via activation of the ghrelin receptor. The major metabolites of ginkgoghrelins in rat bile were detected after intravenous injection and structurally analyzed by mass spectroscopy. Molecular modeling of ginkgoghrelins docking to the ghrelin receptor was exhibited to explore the possible interaction within the binding pocket.

RESULTS

Similar to growth hormone-releasing hormone-6 (GHRP-6), a synthetic analog of ghrelin, ginkgoghrelins were demonstrated to stimulate growth hormone secretion of rat primary anterior pituitary cells in a dose dependent manner, and the stimulation was inhibited by [d-Arg¹, d-Phe⁵, d-Trp^7,9, Leu¹¹]-substance P, an inverse agonist of the ghrelin receptor. Putative metabolites of ginkgoghrelins via glucuronidation and methylation were detected in bile of rats after intravenous injection. Molecular modeling and docking showed that ginkgoghrelins as well as GHRP-6 could fit in and adequately interact with the binding pocket of the ghrelin receptor.

CONCLUSION

The results suggest that ginkgoghrelins are putative components partly accounting for the anti-aging effects of Folium Ginkgo possibly via activation of the ghrelin receptor, and possess great potential to be developed as non-peptidyl analogs of ghrelin.

Growth hormone secretion is diminished and tightly controlled in humans enriched for familial longevity

Reduced growth hormone (GH) signaling has been consistently associated with increased health and lifespan in various mouse models. Here, we assessed GH secretion and its control in relation with human familial longevity. We frequently sampled blood over 24 h in 19 middle‐aged offspring of long‐living families from the Leiden Longevity Study together with 18 of their partners as controls. Circulating GH concentrations were measured every 10 min and insulin‐like growth factor 1 (IGF‐1) and insulin‐like growth factor binding protein 3 (IGFBP3) every 4 h. Using deconvolution analysis, we found that 24‐h total GH secretion was 28% lower (P = 0.04) in offspring [172 (128–216) mU L⁻¹] compared with controls [238 (193–284) mU L⁻¹]. We used approximate entropy (ApEn) to quantify the strength of feedback/feedforward control of GH secretion. ApEn was lower (P = 0.001) in offspring [0.45 (0.39–0.53)] compared with controls [0.66 (0.56–0.77)], indicating tighter control of GH secretion. No significant differences were observed in circulating levels of IGF‐1 and IGFBP3 between offspring and controls. In conclusion, GH secretion in human familial longevity is characterized by diminished secretion rate and more tight control. These data imply that the highly conserved GH signaling pathway, which has been linked to longevity in animal models, is also associated with human longevity.