The complex relationship between obesity and the somatropic axis: the long and winding road

The Association Between Preoperative Insulin-Like Growth Factor 1 Levels and the Total Body Weight Loss in Women Post Laparoscopic Sleeve Gastrectomy

BACKGROUND

Despite the well-described optimal initial clinical response of sleeve gastrectomy (SG) in the treatment of obesity, some patients do not achieve optimal initial clinical response. Insulin-like growth factor-1 (IGF-1) has currently shown an association with post-bariatric surgery weight loss. This study aimed to assess the IGF-1 levels in female patients with obesity, the change after surgery, and their association with the metabolic profile and weight loss after surgery.

PATIENTS AND METHODS

This was a prospective study that was conducted on adult female patients who were recruited for SG. The patients underwent clinical and laboratory investigations that included the IGF-1 measurement. At the 1-year follow-up, the same clinical and laboratory measures were repeated.

RESULTS

This study included 100 female patients. At the 1-year follow-up, there was a statistically significant reduction in body mass index (BMI) (p < 0.001), fasting HbA1C levels (p < 0.001), and triglycerides (p < 0.001), as well as a statistically significant increase in HDL (p < 0.001) and IGF-1 (p < 0.001). Multiple regression analysis revealed that, among the patients baseline characteristics, the significant predictors for the percentage of total weight loss (%TWL) were the patients' BMI (p < 0.001) and IGF-1 levels (p < 0.001). The ROC curve showed that an IGF1 cutoff value of ≤ 23 ng/ml detected suboptimal initial clinical response, with a sensitivity of 95.35% and a specificity of 100%.

CONCLUSION

This study underscores the significant impact of SG on weight loss and metabolic improvements in female patients. Baseline IGF-1 levels emerged as a crucial predictor of optimal initial clinical response.

The Fascinating Interplay between Growth Hormone, Insulin-Like Growth Factor-1, and Insulin

This review intends to provide the reader with a practical overview of several (patho)physiological conditions in which knowledge of the interplay between growth hormone (GH), insulin-like growth factor-1 (IGF-1), and insulin is important. This might help treating physicians in making the right decisions on how to intervene and improve metabolism for the benefit of patients, and to understand why and how metabolism responds in their specific cases. We will specifically address the interplay between GH, IGF-1, and insulin in type 1 and 2 diabetes mellitus, liver cirrhosis, and acromegaly as examples in which this knowledge is truly necessary.

Implications of MCU complex in metabolic diseases

Metabolic diseases are considered the primary culprit for physical and mental health of individuals. Although the diagnosis of these diseases is relatively easy, more effective and convenient potent drugs are still being explored. Ca2+ across the inner mitochondrial membrane is a vital intracellular messenger that regulates energy metabolism and cellular Ca2+ homeostasis and is involved in cell death. Mitochondria rely on a selective mitochondrial Ca2+ unidirectional transport complex (MCU complex) in their inner membrane for Ca2+ uptake. We found that the channel contains several subunits and undergoes dramatic transformations in various pathological processes, especially in metabolic diseases. In this way, we believe that the MCU complex becomes a target with significant potential for these diseases. However, there is no review linking the two factors, thus hindering the possibility of new drug production. Here, we highlight the connection between MCU complex-related Ca2+ transport and the pathophysiology of metabolic diseases, adding understanding and insight at the molecular level to provide new insights for targeting MCU to reverse metabolism-related diseases.

Obesity-induced thymic involution and cancer risk

Declining thymic functions associated either with old age (i.e., age-related thymic involution), or with acute involution as a result of stress, infectious disease, or cytoreductive therapies (e.g., chemotherapy/radiotherapy), have been associated with cancer development. A key mechanism underlying such increased cancer risk is the thymus-dependent debilitation of adaptive immunity, which is responsible for orchestrating immunoediting mechanisms and tumor immune surveillance. In the past few years, a blooming set of evidence has intriguingly linked obesity with cancer development and progression. The majority of such studies has focused on obesity-driven chronic inflammation, steroid/sex hormone and adipokine production, and hyperinsulinemia, as principal factors affecting the tumor microenvironment and driving the development of primary malignancy. However, experimental observations about the negative impact of obesity on T cell development and maturation have existed for more than half a century. Here, we critically discuss the molecular and cellular mechanisms of obesity-driven thymic involution as a previously underrepresented intermediary pathology leading to cancer development and progression. This knowledge could be especially relevant in the context of childhood obesity, because impaired thymic function in young individuals leads to immune system abnormalities, and predisposes to various pediatric cancers. A thorough understanding behind the molecular and cellular circuitries governing obesity-induced thymic involution could therefore help towards the rationalized development of targeted thymic regeneration strategies for obese individuals at high risk of cancer development.

Analysis of clinical features of primary empty sella

OBJECTIVE

A retrospective analysis of clinical data of 60 patients with primary empty sella (PES) was conducted to further improve the understanding of the disease.

METHODS

The clinical data of 60 patients diagnosed with PES admitted to the Department of Endocrinology of Wuhan Union Hospital for different reasons from January 2000 to September 2018 were analyzed.

RESULTS

The 60 cases comprised 22 (36.67%) male and 38 (63.33%) female patients, for a male-to-female ratio of 1:1.73. There was predominance of 50-59 year-olds and women with multiple pregnancies. Of the 60 patients, 41.67% showed fatigue, 26.67% dizziness and headache, 21.67% nausea and vomiting, 18.33% anorexia, and 6.67% visual impairment and other symptoms. Twenty-seven patients (45.0%) had normal pituitary function, and 33 (55.0%) had hypopituitarism. Complete PES was more prone to result in hypopituitarism than partial PES. Men with PES were more likely to have hypopituitarism than women.

CONCLUSION

The incidence of PES was significantly higher in women than in men; PES was common in middle-aged and older women with multiple pregnancies. Symptoms were diverse and clinical manifestations may lack specificity compared to other diseases and need to be differentiated. About half of PES patients may develop hypopituitarism. Therefore, for patients with empty sella detected on magnetic resonance imaging (MRI) with or without clinical symptoms, the pituitary function should be thoroughly and promptly evaluated.

Insulin-like growth factor-1 levels are associated with high comorbidity of metabolic disorders in obese subjects; a Japanese single-center, retrospective-study

Insulin like growth factor-1 (IGF-1) plays important roles in metabolic functions, especially in adulthood. Additionally, obese subjects are reportedly predisposed to having low absolute IGF-1 levels. However, the prevalence and clinical characteristics of obese subjects with low IGF-1 levels are unknown. We examined 64 obese subjects with a body mass index (BMI) ≥ 35 kg/m², with no history of endocrinological disorders, receiving inpatient care. IGF-1 levels were interpreted based on the IGF-1 standard deviation score (SDS) clinically used and standardized by age and sex (low IGF-1 group; ≤ - 2.0 SDS and standard IGF-1 group; - 2.0 < and <  + 2.0 SDS). Notably, 26.6% of the subjects had low IGF-1. Body fat mass and percentage, but not BMI, were significantly higher in the low than in the standard IGF-1 group. Furthermore, natural log-transformed high-sensitivity C-reactive protein, and the frequencies of dyslipidemia and hyperuricemia were higher in the low IGF-1 group. Moreover, among the subjects without diabetes, fasting glucose levels were significantly higher in the low IGF-1 group. Stepwise variable selection procedure revealed body fat percentage to be a parameter most strongly associated with low IGF-1. Thus, low IGF-1 levels may be an important marker of adiposity-associated metabolic disorders in obese patients.

Obesity: A Doorway to a Molecular Path Leading to Infertility

The dramatic rise in obesity has recently made it a global health issue. About 1.9 billion were overweight, and 650 million global populations were obese in 2016. Obese women suffer longer conception time, lowered fertility rates, and greater rates of miscarriage. Obesity alters hormones such as adiponectin and leptin, affecting all levels within the hypothalamic-pituitary-gonadal axis. Advanced glycation end products (AGEs) and monocyte chemotactic protein-1 (MCP-1) are inflammatory cytokines that may play an important role in the pathophysiology of ovarian dysfunction in obesity. In obese males, there are altered sperm parameters, reduced testosterone, increased estradiol, hypogonadism, and epigenetic modifications transmitted to offspring. The focus of this article is on the possible adverse effects on reproductive health resulting from obesity and sheds light on different molecular pathways linking obesity with infertility in both female and male subjects. Electronic databases such as Google Scholar, Embase, Science Direct, PubMed, and Google Search Engine were utilized to find obesity and infertility-related papers. The search strategy is detailed in the method section. Even though multiple research work has shown that obesity impacts fertility in both male and female negatively, it is significant to perform extensive research on the molecular mechanisms that link obesity to infertility. This is to find therapeutics that may be developed aiming at these mechanisms to manage and prevent the negative effects of obesity on the reproductive system.

Associations of Obesity with Linear Growth and Puberty

BACKGROUND

The prevalence of obesity in childhood has increased dramatically in recent decades with increased risk of developing cardiometabolic and other comorbidities. Childhood adiposity may also influence processes of growth and puberty.

SUMMARY

Growth patterns of obesity during childhood have been shown to be associated with increased linear growth in early childhood, leading to accelerated epiphyseal growth plate (EGP) maturation. Several hormones secreted by the adipose tissue may affect linear growth in the context of obesity, both via the growth hormone IGF-1 axis and via a direct effect on the EGP. The observation that children with obesity tend to mature earlier than lean children has led to the assumption that the degree of body fatness may trigger the neuroendocrine events that lead to pubertal onset. The most probable link between obesity and puberty is leptin and its interaction with the kisspeptin system, which is an important regulator of puberty. However, peripheral action of adipose tissue could also be involved in changes in the onset of puberty. In addition, nutritional factors, epigenetics, and endocrine-disrupting chemicals are potential mediators linking pubertal onset to obesity. In this review, we focused on interactions of obesity with linear growth and pubertal processes, based on basic research and clinical data in humans.

KEY MESSAGE

Children with obesity are subject to accelerated linear growth with risk of impaired adult height and early puberty, with its psychological consequences. The data highlight another important objective in combatting childhood obesity, for the prevention of abnormal growth and pubertal patterns.

Time course and reaction types of serum IGF-1 and its relationship to BMI and leptin regarding inpatients with anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) is a severe mental disorder that is characterized by restriction of energy intake, low weight, and endocrine abnormalities. One of the known endocrine changes in relation to underweight is in the GH/IGF-I axis. The aim of the study was (a) to investigate longitudinal characteristics of the IGF-I-change during therapy and weight gain in adult AN, (b) to determine relationships between IGF-I and leptin, (c) to characterize patients with weak and pronounced hormonal reactions to underweight.

DESIGN

Data was assessed from 19 AN patients. Over the first two months, serum IGF-I concentrations were assessed on a weekly basis; thereafter on a monthly basis. The trend of IGF-I values over time was analyzed using individual growth models.

RESULTS

In total, n = 177 IGF-I measurements were analyzed. IGF-I increased significantly dependent on BMI (slope = 20.81, p < 0.001), not modulated by duration of disease. The increase in IGF-I was significantly related to the increase in leptin concentrations over time (slope = 15.57, p < 0.001). Patients with a weaker hormonal reaction to underweight were significantly older compared to patients with a pronounced hormonal reaction (t(17) = 3.07, p = 0.007).

CONCLUSIONS

During treatment, IGF-I change is clearly related to BMI as well as to leptin. Age appears to be associated with the IGF-I response to underweight.

Biochemical discrepancies in the evaluation of the somatotroph axis: Elevated GH or IGF-1 levels do not always diagnose acromegaly

The most frequent diagnosis underlying the finding of an elevated growth hormone (GH) and insulin-like growth factor-1 (IGF-1) is acromegaly due to a GH-secreting pituitary tumour. However, GH and IGF-1 levels can be discordant in patients with acromegaly due to early or partially treated disease, or there might be another cause of high GH or high IGF-1 unrelated to acromegaly, such as pre-analytical and technical pitfalls, physiological circumstances and pathological conditions. High GH and normal or low serum IGF-1, or alternatively, normal GH with elevated serum IGF-1, should be carefully assessed to avoid misinterpreting the activity of acromegaly or misdiagnosing a patient with acromegaly. We summarise here these biochemical discrepancies in the evaluation of the somatotroph axis.

ENDOCRINE OBESITY: Pituitary dysfunction in obesity

Obesity, the growing pandemic of the 21st century, is associated with multiple organ dysfunction, either by a direct increase in fatty organ content or by indirect modifications related to general metabolic changes driven by a specific increase in biologic products. The pituitary gland is not protected against such a situation. Different hypothalamic-pituitary axes experience functional modifications initially oriented to an adaptive situation that, with years of obesity, turn to maladaptive dynamics that contribute to perpetuating obesity and specific symptoms of their hormonal nature. This paper reviews the recent knowledge on obesity-related pituitary dysfunction and its pathogenic mechanisms and discusses potential therapeutic actions aimed at contributing to ameliorating the complex treatment of severe cases of obesity.

Body mass index trajectory from childhood to puberty and high blood pressure: the China Health and Nutrition Survey

OBJECTIVES

The prevalence of childhood hypertension is rising in parallel with the increasing prevalence of overweight and obesity in children. How growth trajectories from childhood to puberty relate to high blood pressure (HBP) is not well defined. We aimed to characterise potential body mass index (BMI) dynamic changing trajectories from childhood to puberty and investigate their association with HBP.

DESIGN

A dynamic prospective cohort.

SETTING

China Health and Nutrition Survey 1991-2015.

PARTICIPANTS

There were 1907 participants (1027 men and 880 women) in this study.

OUTCOMES

The primary outcome was HBP defined as systolic blood pressure (SBP)/diastolic blood pressure (DBP) exceeding the standards or diagnosis by medical records or taking antihypertensive medication.

RESULTS

A model of cubic parameters with three groups was chosen, labelled as normal increasing group (85.16%, n=1624), high increasing group (9.81%, n=187) and resolving group (5.03%, n=96). Compared with the normal increasing group, the unadjusted HRs (95% CIs) for the resolving and high increasing groups were 0.91 (0.45 to 1.86) and 1.88 (1.26 to 2.81), respectively. After adjusting for baseline age, region, sex, baseline BMI z-score, baseline SBP and baseline DBP in model 3, the HRs (95% CIs) for the resolving and high increasing groups were 0.66 (0.30 to 1.45) and 1.56 (1.02 to 2.38).

CONCLUSIONS

These results indicate that the BMI trajectories from childhood to puberty have significant impact on HBP risk. Puberty is a crucial period for the development of HBP.

Weight regain after bariatric surgery: Promoters and potential predictors

Obesity is globally viewed as chronic relapsing disease. Bariatric surgery offers the most efficient and durable weight loss approach. However, weight regain after surgery is a distressing issue as obesity can revert. Surgical procedures were originally designed to reduce food intake and catalyze weight loss, provided that its role is marginalized in long-term weight maintenance. Consequently, it is essential to establish a scientifically standardized applicable definitions for weight regain, which necessitates enhanced comprehension of the clinical situation, as well as have realistic expectations concerning weight loss. Moreover, several factors are proposed to influence weight regain as psychological, behavioral factors, hormonal, metabolic, anatomical lapses, as well as genetic predisposition. Recently, there is a growing evidence of utilization of scoring system to anticipate excess body weight loss, along with characterizing certain biomarkers that identify subjects at risk of suboptimal weight loss after surgery. Furthermore, personalized counseling is warranted to help select bariatric procedure, reinforce self-monitoring skills, motivate patient, encourage mindful eating practices, to avoid recidivism.

Interplay between adipose tissue secreted proteins, eating behavior and obesity

Purpose

Adipokines may play an important role in the complex etiology of human obesity and its metabolic complications. Here, we analyzed the relationship between 15 adipokines, eating behavior and body-mass index (BMI).

Methods

The study included 557 participants of the Sorbs (62.1% women, 37.9% men) and 3101 participants of the population-based LIFE-Adult cohorts (53.4% women, 46.4% men) who completed the German version of the Three-Factor-Eating Questionnaire to assess the eating behavior types cognitive restraint, disinhibition and hunger. Serum levels of 15 adipokines, including adiponectin, adipocyte fatty acid-binding protein (AFABP), angiopoietin-related growth factor (AGF), chemerin, fibroblast growth factor (FGF)-19, FGF-21, FGF-23, insulin-like growth factor (IGF)-1, interleukin (IL) 10, irisin, progranulin, vaspin, pro-neurotensin (pro-NT), pro-enkephalin (PENK) and leptin were measured. Based on significant correlations between several adipokines with different eating behavior items and BMI, we conducted mediation analyses, considering the eating behavior items as potential mediation variable towards BMI.

Results

Here, we found that the positive association between chemerin, AFABP or leptin and BMI in Sorbian women was mediated by higher restraint or disinhibited eating, respectively. Additionally, in Sorbian women, the negative relation between IGF-1 and BMI was mediated by higher disinhibition and the positive link between AGF and BMI by lower disinhibition. In Sorbian men, the negative relationship between PENK and BMI was mediated by lower disinhibition and hunger, whereas the negative relation between IGF-1 and BMI was mediated by higher hunger. In the LIFE-Adult women´s cohort, associations between chemerin and BMI were mediated by decreased hunger or disinhibition, respectively, whereas relations between PENK and BMI were fully mediated by decreased disinhibition.

Conclusion

Our study suggests that adipokines such as PENK, IGF-1, chemerin, AGF, AFABP and leptin might affect the development of obesity by directly modifying individual eating behavior. Given the observational nature of the study, future experimental or mechanistic work is warranted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02687-w.

Growth hormone receptor disrupts glucose homeostasis via promoting and stabilizing retinol binding protein 4

Rationale: The molecular mechanisms underlying the pathogenesis of systemic insulin resistance in type 2 diabetes remain elusive. Growth hormone receptor (GHR) deficiency has long been known to improved insulin sensitivity. However, whether hepatic GHR overexpression or activation is a cause of insulin resistance is still unknown. The aim of this study was to identify the new role of GHR in systemic insulin resistance and explore the underlying mechanism.

Method: Different samples obtained from obese humans, ob/ob mice, db/db mice, high-fat diet (HFD)-fed mice and primary mouse hepatocytes were used to evaluate the correlations between GHR and metabolic disorders. Recombinant adeno-associated viruses encoding GHR and STAT5 and GHR knockout mice were used to investigate the roles of hepatic GHR in glucose homeostasis. Tissue H&E, Oil Red O and PAS staining were performed for histomorphological analysis. Gel filtration chromatography was employed for the separation of serum RBP4-TTR complexes. Plasmids (related to GHR, STAT5 and HIF1α), siRNA oligos (siGHR and siSTAT5), luciferase activity and ChIP assays were used to explore the potential mechanism of hepatic GHR.

Results: Here, we found that hepatic GHR expression was elevated during metabolic disorder. Accordingly, hepatic GHR overexpression disrupted systemic glucose homeostasis by promoting gluconeogenesis and disturbing insulin responsiveness in the liver. Meanwhile, hepatic GHR overexpression promoted lipolysis in white adipose tissue and repressed glucose utilization in skeletal muscle by promoting the circulating level of RBP4, which contributed to impaired systemic insulin action. A mechanistic study revealed that hepatic GHR disrupted systemic insulin sensitivity by increasing RBP4 transcription by activating STAT5. Additionally, overexpression of hepatic GHR promoted TTR transcriptional levels by enhancing the expression of HIF1α, which not only increased the protein stability of RBP4 but also inhibited renal clearance of RBP4 in serum.

Conclusions: Hepatic GHR overexpression and activation accelerated systemic insulin resistance by increasing hepatic RBP4 production and maintaining circulating RBP4 homeostasis. Our current study provides novel insights into the pathogenesis of type 2 diabetes and its associated metabolic complications.

Obesity and its impact on COVID-19

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic has proven a challenge to healthcare systems since its first appearance in late 2019. The global spread and devastating effects of coronavirus disease 2019 (COVID-19) on patients have resulted in countless studies on risk factors and disease progression. Overweight and obesity emerged as one of the major risk factors for developing severe COVID-19. Here we review the biology of coronavirus infections in relation to obesity. In particular, we review literature about the impact of adiposity-related systemic inflammation on the COVID-19 disease severity, involving cytokine, chemokine, leptin, and growth hormone signaling, and we discuss the involvement of hyperactivation of the renin-angiotensin-aldosterone system (RAAS). Due to the sheer number of publications on COVID-19, we cannot be completed, and therefore, we apologize for all the publications that we do not cite.

Association between triglyceride glucose index and peak growth hormone in children with short stature

Growth hormone (GH) secretion is related to many factors, such as weight and puberty, and the reproducibility of GH provocation tests is very poor. This study aimed to evaluate whether the triglyceride (TyG) index was associated with peak GH in children with short stature. This study included 1095 children with short stature divided into two groups based on peak GH level in GH provocation tests [GH deficiency (GHD) group = 733 children; non-GHD group = 362 children]. We found that the TyG index was significantly higher in the GHD group than in the non-GHD group (P < 0.001). A nonlinear relationship was detected between the TyG index and peak GH, whose point was 7.8. A significant negative association between the TyG index and peak GH was observed when the TyG index was greater than 7.8 (β - 2.61, 95% CI - 3.98, - 1.24; P < 0.001), whereas, the relationship between the TyG index and peak GH was not significant when the TyG index was lower than 7.8 (β 0.25, 95% CI - 1.68, 2.17; P = 0.799). There is a nonlinear relationship between the TyG index and peak GH, and a higher TyG index is associated with decreased peak GH in children with short stature.

Reduced Growth Hormone Response to Anaerobic Exercise Among Children With Overweight and Obesity

Hejla, D, Dror, N, Pantanowitz, M, Nemet, D, and Eliakim, A. Reduced growth hormone response to anaerobic exercise among children with overweight and obesity. J Strength Cond Res XX(X): 000-000, 2020-The aim of the present study was to examine the effect of an anaerobic exercise test on growth hormone (GH) secretion in children with overweight and obesity compared with children with normal weight. Fifteen children with overweight (body mass index percentile [BMI%ile] ≥85 < 95) and obesity (BMI%ile ≥95) and 10 children with normal weight (BMI%ile >5 < 85) participated in the study. Subjects performed a modification of the Wingate anaerobic test (WAnT), with 10 bouts of 15-second cycling separated by 1 minute of rest. Blood samples for GH and lactate were collected before and 15, 30, 45, and 60 minutes after the beginning of the exercise test. There was a significant increase in GH levels following the modified repeated WAnT in both groups, but the increase in GH levels was significantly greater among the normal weight children compared with those with overweight and obesity (p < 0.003). Seven of the 10 subjects with normal weight had GH increase above the threshold for GH sufficiency compared with only 2 subjects with overweight and obesity. Growth hormone response to the modified repeated WAnT was significantly reduced among children with overweight and obesity compared with those with normal weight. Anaerobic interval-type training may not be a sufficient exercise alternative to stimulate appropriate GH levels among children with obesity.

Diet-Induced Growth Is Regulated via Acquired Leptin Resistance and Engages a Pomc-Somatostatin-Growth Hormone Circuit

Anorexigenic pro-opiomelanocortin (Pomc)/alpha-melanocyte stimulating hormone (αMSH) neurons of the hypothalamic melanocortin system function as key regulators of energy homeostasis, also controlling somatic growth across different species. However, the mechanisms of melanocortin-dependent growth control still remain ill-defined. Here, we reveal a thus-far-unrecognized structural and functional connection between Pomc neurons and the somatotropic hypothalamo-pituitary axis. Excessive feeding of larval zebrafish causes leptin resistance and reduced levels of the hypothalamic satiety mediator pomca. In turn, this leads to reduced activation of hypophysiotropic somatostatin (Sst)-neurons that express the melanocortin receptor Mc4r, elevated growth hormone (GH) expression in the pituitary, and enhanced somatic growth. Mc4r expression and αMSH responsiveness are conserved in Sst-expressing hypothalamic neurons of mice. Thus, acquired leptin resistance and attenuation of pomca transcription in response to excessive caloric intake may represent an ancient mechanism to promote somatic growth when food resources are plentiful.

Somatotropic Axis and Obesity: Is There Any Role for the Mediterranean Diet?

Obesity is associated with reduced spontaneous and stimulated growth hormone (GH) secretion and basal insulin-like growth factor I (IGF-1) levels—which in turn is associated with increased prevalence of cardiovascular risk factors. The aim of this study was to investigate: (1) the association of somatotropic axis with cardiometabolic status; (2) the association of somatotropic axis with the Mediterranean diet and nutritional pattern in people with obesity. Cross-sectional observational study was carried out in 200 adult women, aged 36.98 ± 11.10 years with severe obesity (body mass index—BMI of 45.19 ± 6.30 kg/m²). The adherence to the Mediterranean diet and the total calorie intake was assessed. Anthropometric measurements, body composition and biochemical profile were determined along with Growth Hormone (GH)/Insulin like Growth Factor 1 (IGF-1) axis and insulin resistance (homeostatic model assessment for insulin resistance—HoMA-IR). The enrolled subjects were compared after being divided according to GH peak response and according to IGF-1 standard deviation scores (SDS). Derangements of GH peak were detected in 61.5% of studied patients while IGF-1 deficiency was detected in 71% of the population. Both blunted GH peak response and IGF-1 SDS were indicators of derangements of somatotropic axis and were associated with comparable results in terms of cardiometabolic sequelae. Both GH peak and IGF-1 levels were inversely associated with anthropometric and metabolic parameters. The adherence to the Mediterranean diet predicts GH peak response. Fatty liver index (FLI), fat mass (FM) and phase angle (PhA) were predictive factors of GH peak response as well. In conclusion derangements of somatotropic axis is associated with a worse cardiometabolic profile in people with obesity. A high adherence to the Mediterranean diet—and in particular protein intake—was associated with a better GH status.

Serum level of insulin-like growth factor-I in type 2 diabetic patients: impact of obesity

Background Insulin-like growth factor-I (IGF-I) is homologous to proinsulin and possesses glucose reducing activity. The association between the level of IGF-I and diabetes has been highlighted. However, this association is controversial due to the influence of different factors including obesity. The aim of the study was to evaluate serum level of IGF-I in type 2 diabetic patients compared to control subjects. Materials and methods A cross-sectional study involving 100 participants was conducted. Serum levels of IGF-I were measured using enzyme-linked immunosorbent assay (ELISA) and the fasting plasma glucose (FPG) levels were measured using the glucose oxidase method. Results IGF-I levels in the diabetic patients were significantly lower than in non-diabetic control subjects (105.13 ± 6.34 vs. 159.96 ± 9.62 ng/mL, p < 0.0001). Among the diabetic group, there was no significant difference in IGF-I levels between obese diabetic patients and non-obese diabetic patients, p = 0.18. Similarly, among the non-diabetic group, a non-significant difference was found in IGF-I levels between obese non-diabetic and non-obese non-diabetic subjects, p = 0.156. However, among the obese group, obese diabetic patients had significantly lower IGF-I serum levels compared to obese non-diabetic subjects (112.07 ± 7.97 vs. 147.07 ± 13.05 ng/mL, p = 0.02). Furthermore, among the non-obese group, the non-obese diabetic patients had significantly lower IGF-I serum levels compared to the non-obese non-diabetic subjects (91.66 ± 9.93 vs. 171.86 ± 13.86 ng/mL, p < 0.0001). No significant associations were observed between IGF-I level and any of the age, gender, body mass index (BMI), FPG levels, or the duration of diabetes. Conclusions Type 2 diabetes mellitus is associated with lower levels of IGF-I regardless to the presence or absence of obesity.

Assessment of Cardiometabolic Risk Factors, Physical Activity Levels, and Quality of Life in Stratified Groups up to 10 Years after Bariatric Surgery

Obesity is a highly prevalent chronic metabolic disease, with an increasing incidence, and is currently approaching epidemic proportions in developing countries. Ouraim was to evaluate the activity levels, quality of life (QoL), clinical parameters, laboratory parameters, and cardiometabolic risk factors afterbariatric surgery (BS). We classified78 patients who underwentBS into four groups, as follows: Those evaluated 1-2 years after BS (BS2), 2-4 years after BS (BS4), 4-6 years after BS (BS6), and 6-10 years after BS (BS+6). Body weight (BW), body mass index (BMI), comorbidities associated with obesity (ACRO), physical activity level, and QoL were evaluated. Patients exhibited improvements in BW, BMI, cardiometabolic risk, hypertension, dyslipidemia, and diabetes and significant changes in lipid profiles in the first postoperative yearafter BS.The physical activity level inthe BS2, BS4, and BS6 groups was increased, compared with that in the first postoperative year, with a decrease in International Physical Activity Questionnaire scores at 1 year in the BS2 (207.50 ± 30.79), BS4 (210.67 ± 33.69), and BS6 (220.00 ± 42.78) groups. The QoL of patients in theBS2 and BS4 groups was excellent and that of patients in the BS4 and BS+6 groupswas very good. These findings suggest that BS promoted improved physical activity levels and QoL and reduced comorbidities in patients with morbid obesity.

Female infertility: which role for obesity?

Obesity is associated with infertility in women through multiple and complex mechanisms. Briefly, the adipose tissue through the production of many factors, such as leptin, free fatty acids (FFA), and cytokines may affect both ovarian and endometrium functions, with a final alteration in oocyte maturation and endometrial epithelium receptivity. In addition, through the development of peripheral insulin resistance obesity produces a condition of functional hyperandrogenism and hyperestrogenism that contribute to produce anovulation and to reduce endometrial receptivity and, therefore participate to cause infertility. Weight loss is able to restore fertility in most cases, but there are no practical indications to guide the clinician to choice the best method among increased physical activity, diet, drugs, and bariatric surgery.

Loss of Growth Hormone Gene (gh1) in Zebrafish Arrests Folliculogenesis in Females and Delays Spermatogenesis in Males

As a master hormone controlling growth and metabolism, GH is also known to regulate reproduction. Studies in mammals have shown that mutations in GH or its receptor (GHR) not only result in retardation in body growth but also reproductive dysfunctions in both sexes. However, the roles of GH in reproduction of other vertebrates are poorly defined. In this study, we created two zebrafish GH (gh1) mutant lines using CRISPR/Cas9. The mutant developed normally up to 14 days postfertilization (dpf); however, a high rate of mortality was observed afterward in both lines, and only a small number of mutant fish could survive to adult stage. The body growth of the mutants was significantly retarded in both sexes in a gene dose-dependent manner compared with their wild-type siblings. A severe dysfunction of gonadal development was observed in survived mutant females, with ovarian folliculogenesis being arrested completely at primary growth stage until 100 dpf. Interestingly, the folliculogenesis in the mutant resumed after months of delay with a certain number of follicles entering vitellogenic growth. As for male reproduction, although the spermatogenesis in mutant males seemed normal in adults, the GH-insufficient heterozygote showed an obvious delay of spermatogenesis (puberty onset) at early developmental stages. The adult mutant males could not breed with wild-type females through natural spawning; however, the sperm isolated from the mutant testes could fertilize eggs through artificial fertilization. This study provides further genetic evidence for the dependence of puberty onset on somatic growth, but not age, in fish.

Serum levels of insulin-like growth factor 1 are negatively associated with log transformation of thyroid-stimulating hormone in Graves' disease patients with hyperthyroidism or subjects with euthyroidism: A prospective observational study

Insulin-like growth factor 1 (IGF-1) has a molecular structure similar to that of insulin. As an essential mediator of growth hormone, IGF-1 plays a vital role in growth of children and anabolic effects of adults. We evaluated the serum levels of IGF-1 in patients with hyperthyroidism or euthyroidism.In this study, 30 patients each of Graves' disease with hyperthyroidism (HY group) and euthyroid individuals (EU group) were recruited. The HY patients were treated with antithyroid regimens as clinically indicated. No medications were given to EU patients. The demographic characteristics and anthropometric and laboratory data of both groups at baseline and 6 months were compared. Associations between levels of IGF-1 and free thyroxine (fT4), thyroid-stimulating hormone (TSH), or log transformation of TSH (logTSH) were analyzed.At baseline, the HY patients had significantly higher serum IGF-1 levels than EU patients (median [Q1, Q3]: 305.4 [257.4, 368.1] vs. 236.7 [184.6, 318.8] ng/mL, P = .007). At 6 months, the HY patients still had higher serum levels of IGF-1 than EU patients (299.5 [249.9, 397.9] vs 222.1 [190.2, 305.4] ng/mL, P = .003). At baseline, the serum levels of IGF-1 in the HY and EU patients were positively associated with fT4 (β = 29.02, P = .002) and negatively associated with TSH (β = -31.46, P = .042) and logTSH (β = -29.04, P = .007). The associations between serum levels of IGF-1 with fT4 or TSH became insignificant at 6 months. However, the serum IGF-1 levels had persistent negative associations with logTSH at 6 months (β = -26.65, P = .021). The negative associations between IGF-1 and logTSH at baseline and 6 months remained significant even after adjustment with sex and age (β = -20.22, P = .023 and β = -20.51, P = .024, respectively).The HY patients had higher serum IGF-1 levels than EU patients. The serum IGF-1 concentrations were negatively associated with logTSH in patients with hyperthyroidism or euthyroidism.

Metabolic and Endocrine Consequences of Bariatric Surgery

Obesity is one of the most serious worldwide epidemics of the twenty-first century according to the World Health Organization. Frequently associated with a number of comorbidities, obesity threatens and compromises individual health and quality of life. Bariatric surgery (BS) has been demonstrated to be an effective treatment to achieve not only sustained weight loss but also significant metabolic improvement that goes beyond mere weight loss. The beneficial effects of BS on metabolic traits are so widely recognized that some authors have proposed BS as metabolic surgery that could be prescribed even for moderate obesity. However, most of the BS procedures imply malabsorption and/or gastric acid reduction which lead to nutrient deficiency and, consequently, further complications could be developed in the long term. In fact, BS not only affects metabolic homeostasis but also has pronounced effects on endocrine systems other than those exclusively involved in metabolic function. The somatotropic, corticotropic, and gonadal axes as well as bone health have also been shown to be affected by the various BS procedures. Accordingly, further consequences and complications of BS in the long term in systems other than metabolic system need to be addressed in large cohorts, taking into account each bariatric procedure before making generalized recommendations for BS. In this review, current data regarding these issues are summarized, paying special attention to the somatotropic, corticotropic, gonadal axes, and bone post-operative health.

Metabolic effects of reduced growth hormone action in fatty liver disease

Background

Adult growth hormone (GH) deficiency is associated with fatty liver disease and shows several features of the metabolic syndrome. Vice versa obesity is characterized as a state of low GH function. Here, we aimed to define the role of hepatic GH signaling and its metabolic consequences in non-alcoholic fatty liver disease.

Methods

In humans, GHR and IGF-1 levels were determined in liver samples of 29 obese patients with non-alcoholic steatohepatitis (NASH) or simple steatosis. Cellular effects of GH on insulin signaling were investigated in GH receptor (GHR) knockdown HepG2 cells.

Results

Hepatic IGF-1 expression levels reflecting GH action were significantly lower and fasting glucose concentrations higher in patients with NASH than in patients with simple steatosis. GHR knockdown in hepatocytes resulted in a scenario of high glucose output displayed by reduced glycogen content, increased gluconeogenesis and diminished insulin signaling.

Conclusions

Our data suggest that GH signaling in the liver is diminished in patients with NASH and associated with deteriorated hepatic insulin sensitivity and metabolic activity. Reduced hepatic GH action might contribute to insulin resistance in obese patients with NASH.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Influence of Maternal Obesity and Breastfeeding on Infant Appetite- and Growth-Related Hormone Concentrations: The SKOT Cohort Studies

BACKGROUND/AIMS

Exposure to obesity during pregnancy may lead to adverse changes in the offspring's metabolic profile. We compared appetite- and growth-related hormones in a cohort of infants born to obese mothers (SKOT-II) with infants born mainly to nonobese mothers (SKOT-I).

METHODS

Infants from SKOT-I (n = 273) and SKOT-II (n = 132) were examined including anthropometric measurements and blood samples analyzed for glucose, insulin, insulin-like growth factor-I (IGF-I), adiponectin, and leptin. Information on breastfeeding and parental characteristics were also collected.

RESULTS

At 9 months of age, SKOT-II infants were 3.6% heavier and 1.2% longer than SKOT-I infants even though their mothers were shorter. There was no difference in body mass index (BMI). SKOT-II infants had higher levels of insulin, adiponectin, and leptin but lower levels of IGF-I compared to SKOT-I infants (all p ≤ 0.015). These differences remained, except for leptin, when adjusted for current weight. Breastfeeding versus nonbreastfeeding at 9 months was associated with lower concentrations of all hormones (all p ≤ 0.003). In adjusted models, maternal BMI at 9 months was positively associated with insulin and adiponectin and negatively with IGF-I.

CONCLUSIONS

Pre-pregnancy obesity confers symmetrically larger infant body size and higher levels of most growth- and appetite-related hormones but surprisingly lower levels of IGF-I, suggesting other possible infant growth-promoting effects through insulin.

The IGF-Axis and Diabetic Retinopathy Before and After Gastric Bypass Surgery

BACKGROUND

Laparoscopic gastric bypass (LGB) abruptly causes remission of type 2 diabetes (T2D). Such dramatic metabolic changes have previously been found to cause worsening of diabetic retinopathy (DR) and circulating insulin-like growth factor I (IGF-I) has been suggested as a causal mediator. We aimed to evaluate baseline imbalances in the circulating IGF-system and changes after LGB in patients with T2D.

METHODS

Prospective ocular examinations and measurement of the IGF-axis before and 3 and 12 months after LGB. IGF-bioactivity was measured by cell-based IGF-I receptor (IGF-IR) kinase activation assay (bioactive IGF). Total IGF-I, IGF-II and IGF binding protein (IGFBP) 1 and 3 were determined by immunoassays.

RESULTS

At baseline, 18 of 36 patients presented with DR. These patients had higher levels of bioactive IGF (p = 0.03) than patients without DR and this association was strengthened in multivariate analysis (p = 0.006). Three patients had worsening of DR, unrelated to other markers. In univariate analysis, bioactive IGF increased at 3 months (p = 0.05) but this change became insignificant in multivariate analysis (p = 0.11). IGFBP-1 increased whereas IGFBP-3 and total IGF-II decreased at the two postoperative visits (p ≤ 0.001). Total IGF-I showed no significant changes. HbA1c, glucose, HOMA-IR and lipids improved after surgery. Two patients did not complete the 12-month visit.

CONCLUSIONS

In obese T2D patients, bioactive IGF is a potential biomarker for DR and levels tended to increase 3 months after bariatric surgery. IGFBP-1 increased while IGFBP-3 and total IGF-II decreased postoperatively, but these changes were unassociated with the development of DR. Markers of the metabolic syndrome improved.

The visceral adiposity index is associated with insulin sensitivity and IGF-I levels in adults with growth hormone deficiency

The visceral adiposity index, based on anthropometric and metabolic parameters, has been shown to be related to adipose tissue function and insulin sensitivity. We aimed to evaluate the performance of the visceral adiposity index in adult patients with growth hormone deficiency. We enrolled 52 patients(mean age 51 ± 13 years) with newly diagnosed growth hormone deficiency and 50 matched healthy subjects as controls at baseline. At baseline and after 12 and 24 months of treatment we evaluated anthropometric measures, lipid profile, glucose and insulin during an oral glucose tolerance test, hemoglobin A1c, homeostasis model assessment estimate of insulin resistance, quantitative insulin sensitivity check index, insulin sensitivity index Matsuda, insulin-like growth factor-I and visceral adiposity index. At baseline growth hormone deficiency patients showed higher waist circumference (p < 0.001), low-density lipoprotein cholesterol (p < 0.001) and visceral adiposity index (p = 0.003) with lower insulin sensitivity index (p = 0.007) and high-density lipoprotein cholesterol (p = 0.001) than controls. During growth hormone treatment we observed a significant increase in insulin-like growth factor-I (p < 0.001), high-density lipoprotein (p < 0.001) with a trend toward increase in insulin sensitivity index (p = 0.055) and a significant decrease in total cholesterol (p < 0.001) and visceral adiposity index (p < 0.001), while no significant changes were observed in other clinical and metabolic parameters. The visceral adiposity index was the only parameter that significantly correlated with growth hormone peak at diagnosis (p < 0.001) and with insulin-like growth factor-I and insulin sensitivity index both at diagnosis (p = 0.009 and p < 0.001) and after 12 (p = 0.026 and p = 0.001) and 24 months (p < 0.001 and p = 0.001) of treatment. The visceral adiposity index, which has shown to be associated with both insulin-like growth factor-I and insulin sensitivity, proved to be the most reliable index of metabolic perturbation, among the most common indexes of adiposity assessment and a marker of benefit during treatment in adult growth hormone deficiency patients.

The Role of the Growth Hormone/Insulin-Like Growth Factor System in Visceral Adiposity

There is substantial evidence that the growth hormone (GH)/insulin-like growth factor (IGF) system is involved in the pathophysiology of obesity. Both GH and IGF-I have direct effects on adipocyte proliferation and differentiation, and this system is involved in the cross-talk between adipose tissue, liver, and pituitary. Transgenic animal models have been of importance in identifying mechanisms underlying these interactions. It emerges that this system has key roles in visceral adiposity, and there is a rationale for targeting this system in the treatment of visceral obesity associated with GH deficiency, metabolic syndrome, and lipodystrophies. This evidence is reviewed, gaps in knowledge are highlighted, and recommendations are made for future research.

Cardiovascular alterations in adult GH deficiency

There is a growing body of evidence indicating that patients with adult GH deficiency (GHD) are characterized by a cluster of traditional and emerging cardiovascular risk factors and markers, which can significantly increase their cardiovascular morbidity and mortality possibly linked to aberrations in GH status. Patients with adult GHD present multiple different cardiovascular abnormalities. In addition, cardiovascular risk in adult GHD is increased due to altered body composition, abnormal lipid profile, insulin resistance and impaired glucose metabolism. Cardiovascular risk factors can be reversed, at least partially, after GH replacement. However, evidence on the effects of GH replacement on cardiovascular events and mortality is too limited in adult GHD patients. Aim of this review is to provide an at-a-glance overview of the role of the GH/IGF-I on the cardiovascular system and the state of art of the effects of GH replacement on cardiovascular system.

GH Responsiveness to Combined GH-Releasing Hormone and Arginine Administration in Obese Patients with Fibromyalgia Syndrome

Reportedly, fibromyalgia (FM) is frequently associated with reduced IGF-1 levels and GH hyporesponsiveness to different GH stimulation tests. Since there is a high prevalence of obesity in FM, and obesity itself is characterized by hyposomatotropism, the aim of this study was to assess IGF-1 levels and GH responsiveness in sixteen severely obese women suffering from FM, who, subdivided into two subgroups on the basis of their age-dependent IGF-1 values (> or <-2 SDS), underwent the combined GHRH plus arginine test. Four out of 16 obese women with FM (25%) had low IGF-1 SDS values, 2 cases of this subgroup (12.5%) failing also to normally respond to the test. Among patients with normal GH responses, 4 showed a delayed GH peak. The subgroup with low IGF-1 SDS values had higher BMI than that with normal IGF-1 SDS. GH peak and area under the curve were not correlated with CRP, ESR, or tender point score, while significant correlations were found with fat-free mass and fat mass. In conclusion, this study shows the existence of a high prevalence of GH-IGF-1 dysfunction in patients with both FM and obesity, presumably as a consequence of the obese rather than fibromyalgic condition.

PAPP-A, IGFBP-4 and IGF-II are secreted by human adipose tissue cultures in a depot-specific manner

OBJECTIVE

Adipose tissue secretes pregnancy-associated plasma protein-A (PAPP-A), which may increase local IGF action through cleavage of IGF-binding protein-4 (IGFBP-4). We tested whether this mechanism was operational in human visceral and subcutaneous adipose tissue (i.e. VAT and SAT).

DESIGN

Explants of VAT and SAT from 26 obese subjects (hereof 17 women, BMI 39.5 (37.2; 42.8) kg/m² (median (25%; 75% confidence interval) and SAT from eight lean, age-matched women (BMI 23.6 (22.4; 24.9) kg/m²) were incubated with or without GH (100 µg/L) and the media were harvested.

METHODS

Media were assessed for concentrations of PAPP-A, intact and PAPP-A-cleaved IGFBP-4, IGF-I and IGF-II, and IGF-I receptor (IGF-IR) activation by bioassay.

RESULTS

In obese subjects, VAT media contained higher concentrations than SAT of PAPP-A (4.4-fold) and both PAPP-A-generated IGFBP-4 fragments (C-terminal: 3.3-fold, N-terminal: 1.5-fold) (all P < 0.0005). Intact IGFBP-4 levels were similar in SAT and VAT. VAT media contained elevated IGF-II (1.4-fold; P < 0.005), but similar IGF-I concentrations compared with SAT. Still, VAT media contained a 1.8-fold increased ability to stimulate the IGF-IR (P < 0.005). IGF-I protein concentration and IGF-IR activation increased more in VAT media than SAT media following GH stimulation (both P < 0.05). At baseline, SAT media protein levels from lean and obese women were similar, with the exception of PAPP-A being 1.8-fold elevated in VAT media (P < 0.05). GH induced a similar increase in IGF-I media levels in SAT from obese and lean women.

CONCLUSION

Human adipose tissue cultures secrete enzymatically active PAPP-A, IGFBP-4 and IGF-II in a depot-specific manner, suggesting differential regulation of IGF activity. Further, IGF-II appears to be more prominent than IGF-I. Finally, VAT appears more GH responsive than SAT.

Could Intermittent Energy Restriction and Intermittent Fasting Reduce Rates of Cancer in Obese, Overweight, and Normal-Weight Subjects? A Summary of Evidence

Animal studies and human observational data link energy restriction (ER) to reduced rates of carcinogenesis. Most of these studies have involved continuous energy restriction (CER), but there is increasing public and scientific interest in the potential health and anticancer effects of intermittent energy restriction (IER) or intermittent fasting (IF), which comprise periods of marked ER or total fasting interspersed with periods of normal eating. This review summarizes animal studies that assessed tumor rates with IER and IF compared with CER or ad libitum feed consumption. The relevance of these animal data to human cancer is also considered by summarizing available human studies of the effects of IER or IF compared with CER on cancer biomarkers in obese, overweight, and normal-weight subjects. IER regimens that include periods of ER alternating with ad libitum feed consumption for 1, 2, or 3 wk have been reported to be superior to CER in reducing tumor rates in most spontaneous mice tumor models. Limited human data from short-term studies (≤6 mo) in overweight and obese subjects have shown that IER can lead to greater improvements in insulin sensitivity (homeostasis model assessment) than can CER, with comparable reductions in adipokines and inflammatory markers and minor changes in the insulin-like growth factor axis. There are currently no data comparing IER or IF with CER in normal-weight subjects. The benefits of IER in these short-term trials are of interest, but not sufficient evidence to recommend the use of IER above CER. Longer-term human studies of adherence to and efficacy and safety of IER are required in obese and overweight subjects, as well as normal-weight subjects.

Bone resorption following weight loss surgery is associated with treatment procedure and changes in secreted Wnt antagonists

To assess if altered bone turnover following bariatric surgery is related to metabolic consequences of the surgical procedure or weight loss. We evaluated serum markers reflecting bone turnover and metabolic pathways at baseline and after 1-year in a controlled non-randomized clinical trial comparing Roux-en-Y gastric bypass surgery (n = 74) with lifestyle intervention (n = 63) on obesity-related comorbidities. The decrease in body mass index (BMI) was larger in the surgery (-14.0 kg/m(2)) compared to lifestyle (-3.7 kg/m(2)). Markedly increased bone turnover was observed following surgery compared to lifestyle intervention and was correlated with change in BMI. Stepwise multivariable regression analysis revealed that group (β = 0.31, p < 0.01), and changes in BMI (β = -0.28, p < 0.01), dickkopf-1 (β = 0.20, p < 0.001) and sclerostin (β = 0.11, p < 0.05) were predictors of change in the bone resorption marker N-terminal telopeptide. Our data support that mechanisms related to the procedure itself and changes in secreted Wnt antagonists may contribute to increased bone turnover following bariatric surgery.

Low insulin-like growth factor 1 is associated with low high-density lipoprotein cholesterol and metabolic syndrome in Chinese nondiabetic obese children and adolescents: a cross-sectional study

Background

Low serum high-density lipoprotein cholesterol (HDL-C) is an independent risk factor for developing cardiovascular disease. Insulin-like growth factor 1(IGF-1) levels have been proven to be positively associated with HDL-C, but few studies were based on the dataset of children or adolescents. The aim of this study is to investigate the relationship among IGF-1, HDL-C and the metabolic syndrome in Chinese nondiabetic obese children and adolescents.

Methods

As a cross-sectional study, this study includes 120 obese Chinese children and adolescents and 120 healthy ones. The obese subjects were divided into two groups based on using 1.03 mmol/L as a threshold value for HDL-C. Clinical examination and laboratory examinations were assessed for all participants.

Results

Obese subjects had significantly lower IGF-1SDS and higher Height SDS than those in the control group. Among 120 obese children and adolescents, 22 (18.3 %) subjects had an HDL-C level <1.03 mmol/L. IGF-1SDS was significantly lower (P = 0.001) in obese subjects with low HDL-C. According to the results of multivariate logistic regression analysis, IGF-1 SDS is significantly associated with low HDL-C(OR 0.518, 95 % CI 0.292–0.916; P = 0.024), after being adjusted for age, gender, pubertal status, BMI SDS, SBP, DBP, HOMR-IR, total cholesterol, low density lipoprotein-cholesterol, triglycerides, ALT and uric acid. In addition, IGF-1 SDS is significantly correlated with the level of serum HDL-C in study population (r = 0.19, P = 0.003). Based on logistic regression analysis with adjustment for age, gender and pubertal status, the increased IGF-1 SDS was associated with a decreased probability of metabolic syndrome (OR 0.555, 95 % CI 0.385–0.801; P = 0.002) and hypertriglyceridemia (OR 0.582, 95 % CI 0.395–0.856; P = 0.006), but no significant correlation with hypertension.

Conclusion

Obese children had lower IGF-1SDS and taller stature compared with the control group. Low levels of IGF-1 SDS were associated with low levels of HDL-C in chinese nondiabetic obese children and adolescents, independent of insulin resistance, as well as other traditional cardiovascular disease risk markers.

Copeptin under glucagon stimulation

Stimulation of growth hormone (GH) and adrenocorticotropic hormone (ACTH) secretion by glucagon is a standard procedure to assess pituitary dysfunction but the pathomechanism of glucagon action remains unclear. As arginine vasopressin (AVP) may act on the release of both, GH and ACTH, we tested here the role of AVP in GST by measuring a stable precursor fragment, copeptin, which is stoichiometrically secreted with AVP in a 1:1 ratio. ACTH, cortisol, GH, and copeptin were measured at 0, 60, 90, 120, 150, and 180 min during GST in 79 subjects: healthy controls (Group 1, n = 32), subjects with pituitary disease, but with adequate cortisol and GH responses during GST (Group 2, n = 29), and those with overt hypopituitarism (Group 3, n = 18). Copeptin concentrations significantly increased over baseline 150 and 180 min following glucagon stimulation in controls and patients with intact pituitary function but not in hypopituitarism. Copeptin concentrations were stimulated over time and the maximal increment correlated with ACTH, while correlations between copeptin and GH were weaker. Interestingly, copeptin as well as GH secretion was significantly attenuated when comparing subjects within the highest to those in the lowest BMI quartile (p < 0.05). Copeptin is significantly released following glucagon stimulation. As this release is BMI-dependent, the time-dependent relation between copeptin and GH may be obscured, whereas the close relation to ACTH suggests that AVP/copeptin release might be linked to the activation of the adrenal axis.

IGF-1 Levels are Inversely Associated With Metabolic Syndrome in Obstructive Sleep Apnea

STUDY OBJECTIVES

This study examined insulin-like growth factor-1 (IGF-1) production and its association with the metabolic syndrome (MS) in men with obstructive sleep apnea (OSA).

METHODS

In total, 47 overweight and obese men who had been referred for suspected OSA underwent polysomnography and were classified based on the apnea-hypopnea index (AHI) into three groups: no OSA, < 5 events/h (n = 11); mild OSA, ≥ 5 to < 15 events/h (n = 8); and moderate-severe OSA, ≥ 15 events/h (n = 28). The assessment of the somatotropic axis function included IGF-1 measurement. MS was diagnosed according to the National Cholesterol Education Program guidelines.

RESULTS

IGF-1 level in the moderate-severe OSA group was lower than in the no-OSA group (156.8 ± 54.3 μg/L versus 225.5 ± 80.5 μg/L; p = 0.013). IGF-1 level was negatively correlated with body mass index, waist circumference (WC), AHI, and sleep duration with oxygen (O2) saturation < 90% and positively correlated with the average and minimum O2 saturation (p = 0.027). In a multivariable linear regression, considering WC and minimum O2 saturation as independent variables, only the minimum O2 saturation was a predictor of low IGF-1 levels. The proportions of patients with MS were different between the three groups (18.2% in no OSA; 25% in mild OSA, and 57.1% in moderate-severe OSA; p = 0.047). Furthermore, in the lowest tertile of IGF-1 value, 66.7% of patients were affected by MS (p = 0.049). Hemoglobin (Hb)A1c correlated negatively with the minimum O2 saturation and IGF-1 levels. However, in multivariable linear regression only IGF-1 levels were a predictor of HbA1c levels.

CONCLUSION

The occurrence of OSA is associated with a reduction in IGF-1 levels. IGF-1 alterations in OSA also seem to be associated with a higher prevalence of MS.

Klotho and the Growth Hormone/Insulin-Like Growth Factor 1 Axis: Novel Insights into Complex Interactions

The growth hormone (GH)/insulin-like growth factor (IGF)-1 axis is pivotal for many metabolic functions, including proper development and growth of bones, skeletal muscles, and adipose tissue. Defects in the axis' activity during childhood result in growth abnormalities, while increased secretion of GH from the pituitary results in acromegaly. In order to keep narrow physiologic concentration, GH and IGF-1 secretion and activity are tightly regulated by hypothalamic, pituitary, endocrine, paracrine, and autocrine factors. Klotho was first discovered as an aging-suppressor gene. Mice that do not express klotho die prematurely with multiple symptoms of aging, several of them are also characteristic of decreased GH/IGF-1 axis activity. Klotho is highly expressed in the brain, the kidney, and parathyroid and pituitary glands, but can also serve as a circulating hormone by its shedding, forming soluble klotho that can be detected in blood, cerebrospinal fluid, and urine. Several lines of evidence suggest an association between klotho levels and activity of the GH/IGF-1 axis: the GH-secreting cells in the anterior pituitary of klotho-deficient mice are hypotrophic; klotho levels are altered in subjects with pathologies of the GH/IGF-1 axis; and accumulating data indicate that klotho is a direct regulator of GH secretion. Thus, klotho seems to be a new player in the intricate regulation of the GH/IGF-1 axis.

Insulin-like growth factor-1 deficiency and metabolic syndrome

Consistent evidence associates IGF-1 deficiency and metabolic syndrome. In this review, we will focus on the metabolic effects of IGF-1, the concept of metabolic syndrome and its clinical manifestations (impaired lipid profile, insulin resistance, increased glucose levels, obesity, and cardiovascular disease), discussing whether IGF-1 replacement therapy could be a beneficial strategy for these patients. The search plan was made in Medline for Pubmed with the following mesh terms: IGF-1 and "metabolism, carbohydrate, lipids, proteins, amino acids, metabolic syndrome, cardiovascular disease, diabetes" between the years 1963-2015. The search includes animal and human protocols. In this review we discuss the relevant actions of IGF-1 on metabolism and the implication of IGF-1 deficiency in the establishment of metabolic syndrome. Multiple studies (in vitro and in vivo) demonstrate the association between IGF-1 deficit and deregulated lipid metabolism, cardiovascular disease, diabetes, and an altered metabolic profile of diabetic patients. Based on the available data we propose IGF-1 as a key hormone in the pathophysiology of metabolic syndrome; due to its implications in the metabolism of carbohydrates and lipids. Previous data demonstrates how IGF-1 can be an effective option in the treatment of this worldwide increasing condition. It has to distinguished that the replacement therapy should be only undertaken to restore the physiological levels, never to exceed physiological ranges.

Influence of nutrition on somatotropic axis: Milk consumption in adult individuals with moderate-severe obesity

BACKGROUND & AIMS

Nutrition is the major environmental factor that influences the risk of developing pathologies, such as obesity. Although a number of recent reviews pinpoint a protective effects of milk on body weight and obesity related co-morbidities, an inaccurate estimate of milk might contribute to hamper its beneficial effects on health outcomes. Seven-day food records provide prospective food intake data, reducing recall bias and providing extra details about specific food items. Milk intake stimulates the somatotropic axis at multiple levels by increasing both growth hormone (GH) and insulin-like growth factor-1 (IGF-1) secretion. On the other hand, obesity is associated with reduced spontaneous and stimulated GH secretion and basal IGF-1 levels. Aim of this study was to evaluate the milk consumption by using the 7-days food record in obese individuals and to investigate the association between milk intake and GH secretory status in these subjects.

METHODS

Cross-sectional observational study carried out on 281 adult individuals (200 women and 81 men, aged 18-74 years) with moderate-severe obesity (BMI 35.2-69.4 kg/m²). Baseline milk intake data were collected using a 7 day food record. Anthropometric measurements and biochemical profile were determined. The GH/IGF-1 axis was evaluated by peak GH response after GHRH + ARGININE and IGF-1 standard deviation score (SDS).

RESULTS

The majority of individuals (72.2%) reported consuming milk; 250 mL low-fat milk was the most frequently serving of milk consumed, while no subjects reported to consume whole milk. Milk consumers vs no milk consumers presented the better anthropometric measurements and metabolic profile. At the bivariate proportional odds ratio model, after adjusting for BMI, age and gender, milk consumption was associated the better GH status (OR = 0.60; p < 0.001). Among milk consumers, subjects consuming 250 mL reduced-fat milk vs 250 mL low-fat milk presented the better anthropometric measurements and metabolic profile. At the bivariate proportional odds ratio model, after adjusting for BMI, age and gender, the consume of 250 mL reduced-fat milk was associated better GH status (OR = 0.54; p = 0.003).

CONCLUSIONS

A novel positive association between milk consumption, GH status, and metabolic profile in obese individuals was evidenced. Regardless of the pathogenetic mechanisms, this novel association might be relevant in a context where commonly obese individuals skip breakfast, and suggests the need of a growing cooperation between Nutritionists and Endocrinologists in the management of the obese patients.

Association between exonic polymorphism (rs629849, Gly1619Arg) of IGF2R gene and obesity in Korean population

The aim of this study is to investigate the relationship between single nucleotide polymorphisms (SNPs) and susceptibility to obesity. A previous study suggested that insulin-like growth factors (IGFs) may affect obesity and that IGFs regulate cellular signals by receptors that include the insulin-like growth factor 1 receptor (IGF1R) and the insulin-like growth factor 2 receptor (IGF2R). In this research, the rs3743262 and rs2229765 SNPs of IGF1R gene and rs629849 and rs1805075 SNPs of IG-F2R gene were genotyped in 120 overweight and obese patients with a BMI≥23 kg/m2 (Body Mass Index) and 123 healthy controls with a BMI of 18.5–23.0 kg/m2. Genotyping of each SNP was performed by direct sequencing. Among tested SNPs in IGF1R and IGF2R genes, rs629849 SNP of IGF2R gene showed significant association with obesity (OR=1.86, 95% CI=1.02–3.40, P=0.044 in codominant1 model; OR=1.99, 95% CI=1.10–3.57, P=0.020 in dominant model; OR=1.93, 95% CI=1.13–3.31, P=0.013 in log-additive model). And allele distribution between the control group and overweight/obese group also showed significant difference (OR=1.93, 95% CI=1.14–3.28, P=0.015). In conclusion, these results indicate that rs629849 SNP of IGF2R might be contributed to development of obesity in the Korean population.

Fat Mass and Obesity Associated Gene Variants Are Associated With Increased Growth Hormone Levels and Affect Glucose and Lipid Metabolism in Lean Women

First intron variability of the fat mass and obesity associated gene (FTO) has strong impact on adiposity. We focused on lean women carrying the most “obesity-risk” haplotype to study their anthropometric parameters and hormonal and metabolic profile. Genotype-phenotype correlation was performed in a group of 172 lean women (body mass index (BMI) 18.5 and 25 kg/m2; age 26.8±7.26 years), 77 of them used hormonal contraceptives. Even in lean women the association of the risk haplotype CAGA with BMI was confirmed but it did not influence the anthropometric indices of body composition. CAGA carriers compared to non-carriers had significantly higher both fasting (p=0.016) and post glucose load (p<0.001) levels of growth hormone (GH), significantly higher glucose, insulin and C-peptide levels in the late phase of oGTT and lower fasting concentration of total cholesterol and LDL-cholesterol. Administration of hormonal contraceptives further increased observed hormonal and metabolic effects in CAGA carriers. We conclude that higher levels of GH in lean women carrying the FTO “obesity risk” haplotype could protect them from the development of obesity. The relation between the FTO gene variability and GH secretion has to be elucidated. This is the first study demonstrating the interaction of FTO genotype with hormonal contraception.

Altered liver expression of genes involved in lipid and glucose metabolism in mice with partial IGF-1 deficiency: an experimental approach to metabolic syndrome

Background

Insulin growth factor 1 (IGF-1) has multiple effects on metabolism. Much evidence suggests that the deficiency of this hormone increases insulin resistance, impairs lipid metabolism, augments oxidative damage and deregulates the neuro-hormonal axis. An inverse relationship between IGF-1 levels and the prevalence of Metabolic Syndrome (MetS) with its cardiovascular complications has been identified. However, the underlying mechanisms linking IGF-1 and MetS are still poorly understood. In order to elucidate such mechanisms, the aim of this work was to study, in mice with partial IGF-1 deficiency, liver expression of genes involved in glucose and lipid metabolism as well as serum levels of glucose, triglycerides and cholesterol, as well as liver malondialdehyde (MDA) levels, as a marker for oxidative damage.

Methods

Three experimental groups were studied in parallel: Controls (CO), wild type mice (igf-1^+/+); untreated heterozygous mice (Hz, igf-1^+/−) and Hz (igf-1^+/−) mice treated with low doses of IGF-1 for 10 days (Hz + IGF-1).

Results

A reduction of IGF-1 serum levels in the Hz group was found, which was normalized by IGF-1 therapy. Serum levels of glucose, triglycerides and cholesterol were significantly increased in the untreated Hz group as compared to both controls and Hz + IGF-1 groups. The expression of genes involved in gluconeogenesis, glycogenolysis, lipid synthesis and transport, and catabolism were altered in untreated Hz animals and the expression of most of them was normalized by IGF-1 therapy; MDA was also significantly increased in the Hz untreated group.

Conclusions

The mere partial IGF-1 deficiency is responsible for the reduction in the expression of genes involved in glucose and lipid metabolism, resulting in dyslipidemia and hyperglycemia. Such genetic alterations may seriously contribute to the establishment of MetS.

Insulin-Like Growth Factor-1 and Resistance Exercise in Community Dwelling Old Adults

BACKGROUND

Insulin-like growth factor-1 (IGF-1) is related to the preservation of lean body mass. Its decline during ageing is thought to make old adults more susceptible to sarcopenia and functional dependency. The aim of the present study was to investigate circulating total IGF-1 in old adults who engaged in a 12-weeks of progressive resistance training.

DESIGN

Intervention study.

SETTING

Community.

PARTICIPANTS

Old Icelandic adults (N = 235, 73.7 ± 5.7 years, 58.2% female).

INTERVENTION

Twelve-week resistance exercise program (3 times/week; 3 sets, 6-8 repetitions at 75-80% of the 1-repetition maximum) designed to increase strength and muscle mass of major muscle groups.

MEASUREMENTS

IGF-1.

RESULTS

At baseline IGF-1 was significantly associated with lean body mass and appendicular muscle mass (also when corrected for age, gender and various covariates). After the training IGF-1 decreased significantly from 112.1 ± 35.6 to 106.1 ± 35.2 µg/L during the course of the study. On and individual level, IGF-1 decreased in 59% and increased in 39% of the participants. Changes in IGF-1 were inversely related to changes in lean body mass (rho = -0.176, P = 0.013 ) and appendicular muscle mass (rho = -0.162, P = 0.019) also when corrected for protein intake, age, gender, and other covariates.

CONCLUSION

Serum total IGF-1 decreases after 12 weeks of resistance exercise in community dwelling old adults. When looked at IGF-1 changes for participants individually it becomes clear that IGF-1 response to resistances exercise is highly variable. Changes in IGF-1 are negatively related to changes in lean body mass during training, which supports the hypothesis that IGF-1 is redistributed from circulation into tissue during periods of active muscle building.