Interleukin-6 in obese children and adolescents with and without glucose intolerance

IL-6 Trans-Signaling Is Increased in Diabetes, Impacted by Glucolipotoxicity, and Associated With Liver Stiffness and Fibrosis in Fatty Liver Disease

Many people living with diabetes also have nonalcoholic fatty liver disease (NAFLD). Interleukin-6 (IL-6) is involved in both diseases, interacting with both membrane-bound (classical) and circulating (trans-signaling) soluble receptors. We investigated whether secretion of IL-6 trans-signaling coreceptors are altered in NAFLD by diabetes and whether this might associate with the severity of fatty liver disease. Secretion patterns were investigated with use of human hepatocyte, stellate, and monocyte cell lines. Associations with liver pathology were investigated in two patient cohorts: 1) biopsy-confirmed steatohepatitis and 2) class 3 obesity. We found that exposure of stellate cells to high glucose and palmitate increased IL-6 and soluble gp130 (sgp130) secretion. In line with this, plasma sgp130 in both patient cohorts positively correlated with HbA1c, and subjects with diabetes had higher circulating levels of IL-6 and trans-signaling coreceptors. Plasma sgp130 strongly correlated with liver stiffness and was significantly increased in subjects with F4 fibrosis stage. Monocyte activation was associated with reduced sIL-6R secretion. These data suggest that hyperglycemia and hyperlipidemia can directly impact IL-6 trans-signaling and that this may be linked to enhanced severity of NAFLD in patients with concomitant diabetes.

ARTICLE HIGHLIGHTS

IL-6 and its circulating coreceptor sgp130 are increased in people with fatty liver disease and steatohepatitis. High glucose and lipids stimulated IL-6 and sgp130 secretion from hepatic stellate cells. sgp130 levels correlated with HbA1c, and diabetes concurrent with steatohepatitis further increased circulating levels of all IL-6 trans-signaling mediators. Circulating sgp130 positively correlated with liver stiffness and hepatic fibrosis. Metabolic stress to liver associated with fatty liver disease might shift the balance of IL-6 classical versus trans-signaling, promoting liver fibrosis that is accelerated by diabetes.

High tissue-sodium associates with systemic inflammation and insulin resistance in obese individuals

BACKGROUND AND AIMS

High sodium intake is associated with obesity and insulin resistance, and high extracellular sodium content may induce systemic inflammation, leading to cardiovascular disease. In this study, we aim to investigate whether high tissue sodium accumulation relates with obesity-related insulin resistance and whether the pro-inflammatory effects of excess tissue sodium accumulation may contribute to such association.

METHODS AND RESULTS

In a cross-sectional study of 30 obese and 53 non-obese subjects, we measured insulin sensitivity determined as glucose disposal rate (GDR) using hyperinsulinemic euglycemic clamp, and tissue sodium content using 23Na magnetic resonance imaging. Median age was 48 years, 68% were female and 41% were African American. Median (interquartile range) BMI was 33 (31.5, 36.3) and 25 (23.5, 27.2) kg/m2 in the obese and non-obese individuals, respectively. In obese individuals, insulin sensitivity negatively correlated with muscle (r = -0.45, p = 0.01) and skin sodium (r = -0.46, p = 0.01). In interaction analysis among obese individuals, tissue sodium had a greater effect on insulin sensitivity at higher levels of high-sensitivity C-reactive protein (p-interaction = 0.03 and 0.01 for muscle and skin Na+, respectively) and interleukin-6 (p-interaction = 0.024 and 0.003 for muscle and skin Na+, respectively). In interaction analysis of the entire cohort, the association between muscle sodium and insulin sensitivity was stronger with increasing levels of serum leptin (p-interaction = 0.01).

CONCLUSIONS

Higher muscle and skin sodium are associated with insulin resistance in obese patients. Whether high tissue sodium accumulation has a mechanistic role in the development of obesity-related insulin resistance through systemic inflammation and leptin dysregulation remains to be examined in future studies.

CLINICALTRIALS

gov registration: NCT02236520.

Case report: Molecular characterisation of adipose-tissue derived cells from a patient with ROHHAD syndrome

There have been over 100 cases of Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) syndrome reported, but there is currently no curative treatment for children with this condition. We aimed to better characterise adipose cells from a child with ROHHAD syndrome. We isolated pre-adipocytes from a 4 year-old female patient with ROHHAD syndrome and assessed proliferation rate of these cells. We evaluated levels of DLP-Pref-1(pre-adipocyte marker) using western blotting, and concentrations of interleukin-6(IL-6) using ELISA. We performed next-generation sequencing (NGS) and bioinformatic analyses on these cells compared to tissue from an age/sex-matched control. The two most up-/down-regulated genes were validated using QPCR. We successfully isolated pre-adipocytes from a fat biopsy, by confirming the presence of Pref-1 and differentiated them to mature adipocytes. Interleukin 6, (Il-6) levels were 5.6-fold higher in ROHHAD cells compared to a control age/sex-matched biopsy. NGS revealed 25,703 differentially expressed genes (DEGs) from ROHHAD cells vs. control of which 2,237 genes were significantly altered. The 20 most significantly up/down-regulated genes were selected for discussion. This paper describes the first transcriptomic analysis of adipose cells from a child with ROHHAD vs. normal control adipose tissue as a first step in identifying targetable pathways/mechanisms underlying this condition with novel therapeutic interventions.

Molecular Biomarkers for Cardiometabolic Disease: Risk Assessment in Young Individuals

Cardiometabolic diseases, including cardiovascular disease and diabetes, are major causes of morbidity and mortality worldwide. Despite progress in prevention and treatment, recent trends show a stalling in the reduction of cardiovascular disease morbidity and mortality, paralleled by increasing rates of cardiometabolic disease risk factors in young adults, underscoring the importance of risk assessments in this population. This review highlights the evidence for molecular biomarkers for early risk assessment in young individuals. We examine the utility of traditional biomarkers in young individuals and discuss novel, nontraditional biomarkers specific to pathways contributing to early cardiometabolic disease risk. Additionally, we explore emerging omic technologies and analytical approaches that could enhance risk assessment for cardiometabolic disease.

Obesity Programs Macrophages to Support Cancer Progression

Obesity induces multifactorial effects such as dyslipidemia, insulin resistance, and arterial hypertension that influence the progression of many diseases. Obesity is associated with an increased incidence of cancers, and multiple mechanisms link obesity with cancer initiation and progression. Macrophages participate in the homeostasis of adipose tissue and play an important role in cancer. Adipose tissue expansion in obesity alters the balance between pro- and anti-inflammatory macrophages, which is a primary cause of inflammation. Chronic low-grade inflammation driven by macrophages is also an important characteristic of cancer. Adipocytes secrete various adipokines, including adiponectin, leptin, IL6, and TNFα, that influence macrophage behavior and tumor progression. Furthermore, other metabolic effects of obesity, such as hyperlipidemia, hyperglycemia, and hypercholesterolemia, can also regulate macrophage functionality in cancer. This review summarizes how obesity influences macrophage-tumor cell interactions and the role of macrophages in the response to anticancer therapies under obese conditions.

Cardiorespiratory fitness in children with overweight/obesity: Insights into the molecular mechanisms

OBJECTIVES

High cardiorespiratory fitness (CRF) levels reduce the risk of developing cardiovascular disease (CVD) during adulthood. However, little is known about the molecular mechanisms underlying the health benefits of high CRF levels at the early stage of life. This study aimed to analyze the whole-blood transcriptome profile of fit children with overweight/obesity (OW/OB) compared to unfit children with OW/OB.

DESIGN

27 children with OW/OB (10.14 ± 1.3 years, 59% boys) from the ActiveBrains project were evaluated. VO₂ peak was assessed using a gas analyzer, and participants were categorized into fit or unfit according to the CVD risk-related cut-points. Whole-blood transcriptome profile (RNA sequencing) was analyzed. Differential gene expression analysis was performed using the limma R/Bioconductor software package (analyses adjusted by sex and maturational status), and pathways' enrichment analysis was performed with DAVID. In addition, in silico validation data mining was performed using the PHENOPEDIA database.

RESULTS

256 genes were differentially expressed in fit children with OW/OB compared to unfit children with OW/OB after adjusting by sex and maturational status (FDR < 0.05). Enriched pathway analysis identified gene pathways related to inflammation (eg, dopaminergic and GABAergic synapse pathways). Interestingly, in silico validation data mining detected a set of the differentially expressed genes to be related to CVD, metabolic syndrome, hypertension, inflammation, and asthma.

CONCLUSION

The distinct pattern of whole-blood gene expression in fit children with OW/OB reveals genes and gene pathways that might play a role in reducing CVD risk factors later in life.

LIFR-α-dependent adipocyte signaling in obesity limits adipose expansion contributing to fatty liver disease

The role of chronic adipose inflammation in diet-induced obesity (DIO) and its sequelae including fatty liver disease remains unclear. Leukemia inhibitory factor (LIF) induces JAK-dependent adipocyte lipolysis and altered adipo/cytokine expression, suppressing in vivo adipose expansion in normal and obese mouse models. To characterize LIF receptor (LIFR-α)-dependent cytokine signaling in DIO, we created an adipocyte-specific LIFR knockout mouse model (Adipoq-Cre;LIFR^fl/fl). Differentiated adipocytes derived from this model blocked LIF-induced triacylglycerol lipolysis. Adipoq-Cre;LIFR^fl/fl mice on a high-fat diet (HFD) displayed reduced adipose STAT3 activation, 50% expansion in adipose, 20% body weight increase, and a 75% reduction in total hepatic triacylglycerides compared with controls. To demonstrate that LIFR-α signals adipocytes through STAT3, we also created an Adipoq-Cre;STAT3^fl/fl model that showed similar findings when fed a HFD as Adipoq-Cre;LIFR^fl/fl mice. These findings establish the importance of obesity-associated LIFR-α/JAK/STAT3 inflammatory signaling in adipocytes, blocking further adipose expansion in DIO contributing to ectopic liver triacylglyceride accumulation.

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LIFR-α signaling induces adipocyte lipolysis, restricting adipose expansion in DIO

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LIFR-α signaling requires STAT3 for adipocyte lipolysis

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LIFR-α/JAK/STAT3 lipolysis signaling in adipocytes promotes hepatic steatosis

High-Fat Diet from Weaning until Early Adulthood Impairs T Cell Development in the Thymus

The growing prevalence of childhood obesity has become a serious health problem over the past few decades. Although the immune system is greatly affected by childhood obesity, whether obesity influences the T cell development in the thymus is poorly understood. In this study, we used a high-fat diet (HFD)-induced obesity mice model to study the influence of HFD from weaning on the thymus. C57BL/6 mice (male, 3 weeks old) were fed a HFD or standard diet (lean controls) for 6 weeks. The bodyweight of mice fed with an HFD was 28% higher than that in the control group, while the thymus weight of HFD mice decreased by 15% compared with controls. As expected, thymic triacylglycerol content of the HFD mice increased by 37% compared to the control mice. Importantly, the frequencies of CD4⁺ and CD8⁺ single-positive (SP) thymocytes decreased by 38% and 44%, respectively. The apoptotic analysis revealed that thymic tissue of HFD mice had a higher level of Annexin-V positive thymocytes than control animals. Furthermore, the immunoblotting analysis showed that survival signal pathways in the thymus were impaired in the HFD mice, including the AKT/mTOR and ERK pathways. With the analysis of T-cell receptor excision circles (TREC), we found that HFD-induced obesity decreased recent thymic emigrants in spleen tissue. Our findings indicate that HFD from the weaning period impairs T cell development in the thymus, possibly by induction of apoptosis of thymocytes, involving disruption of survival signal pathways.

Prenatal pesticide exposure associated with glycated haemoglobin and markers of metabolic dysfunction in adolescents

BACKGROUND

Pesticide exposure has been associated with increased risk of diabetes mellitus in adults, but potential effects of prenatal exposure on glucose regulation have not been investigated. The aim of this study was to investigate if maternal occupational pesticide exposure in pregnancy was associated with glycated haemoglobin A1c (HbA1c) in adolescents and whether an association was modified by sex and paraoxonase-1 (PON1) Q192R polymorphism.

METHODS

A prospective cohort study of children whose mothers were either occupationally exposed or unexposed to pesticides in early pregnancy. At age 10-to-16 years, the children (n = 168) underwent clinical examinations including pubertal stage assessment (accepted by 141 children) and blood sampling. PON1 Q192R genotype was available for 139 children and 103 mothers. The main outcome measure was HbA1c but other relevant biomarkers were also included.

RESULTS

Prenatal pesticide exposure was associated with a 5.0% (95% confidence interval: 1.8; 8.2) higher HbA1c compared to unexposed children after adjustment for confounders. After stratification, the association remained significant for girls (6.2% (1.6; 11.1)) and if the child or the mother had the PON1 192R-allele (6.1% (1.6; 10.8) and 7.1% (2.0; 12.6), respectively). Besides, an exposure-related increase was seen for the leptin-to-adiponectin ratio, for plasminogen activator inhibitor type-1 in girls, and for interleukin-6 in children whose mothers had the R-allele.

CONCLUSION

Prenatal pesticide exposure was associated with higher HbA1c and changes in related biomarkers in adolescents. Our results suggest an adverse effect on glucose homeostasis and support previous findings from this cohort of an exposure-associated metabolic risk profile with higher susceptibility related to female sex and the PON1 192R-allele.

Influence of Interleukin-6 (174G/C) Gene Polymorphism on Obesity in Egyptian Children

BACKGROUND:

Obesity is a multi-factorial chronic disorder. A considerable number of studies have been performed to figure out whether there is an association between obesity and polymorphisms of gene IL-6 (174G/C), but the results are equivocal.

AIM:

This study aimed to find out whether the IL-6 (174G/C) gene was associated with the risk of developing obesity in Egyptian children.

SUBJECTS AND METHODS:

The study included 149 children and adolescents with age ranged between 9.5 – 18 years. Eighty-five of them were obese which BMIZ-score is > 2, and sixty-four children with BMIZ-score ≤ 2 served as control group. Serum level of IL-6 and genetic analysis for IL-6 (174G/C) gene polymorphism were done.

RESULTS:

Obese children had significantly higher serum levels of IL-6 as compared to those of control children (P = 0.003). A high percentage of IL-6 polymorphism GC was found in obese subjects (93.7%), while the control group had a higher percentage of IL-6 polymorphism GG (70.6 %).

CONCLUSION:

Our study showed that carriers of the C allele for the IL-6 (174G/C) polymorphism have higher BMI. As the G174C polymorphism is likely to affect IL-6 expression and its physiological regulation; consequently this polymorphism may affect adiposity.

Childhood adiposity and risk of type 1 diabetes: A Mendelian randomization study

BACKGROUND

The incidence of type 1 diabetes (T1D) is increasing globally. One hypothesis is that increasing childhood obesity rates may explain part of this increase, but, as T1D is rare, intervention studies are challenging to perform. The aim of this study was to assess this hypothesis with a Mendelian randomization approach that uses genetic variants as instrumental variables to test for causal associations.

METHODS AND FINDINGS

We created a genetic instrument of 23 single nucleotide polymorphisms (SNPs) associated with childhood adiposity in children aged 2-10 years. Summary-level association results for these 23 SNPs with childhood-onset (<17 years) T1D were extracted from a meta-analysis of genome-wide association study with 5,913 T1D cases and 8,828 reference samples. Using inverse-variance weighted Mendelian randomization analysis, we found support for an effect of childhood adiposity on T1D risk (odds ratio 1.32, 95% CI 1.06-1.64 per standard deviation score in body mass index [SDS-BMI]). A sensitivity analysis provided evidence of horizontal pleiotropy bias (p = 0.04) diluting the estimates towards the null. We therefore applied Egger regression and multivariable Mendelian randomization methods to control for this type of bias and found evidence in support of a role of childhood adiposity in T1D (odds ratio in Egger regression, 2.76, 95% CI 1.40-5.44). Limitations of our study include that underlying genes and their mechanisms for most of the genetic variants included in the score are not known. Mendelian randomization requires large sample sizes, and power was limited to provide precise estimates. This research has been conducted using data from the Early Growth Genetics (EGG) Consortium, the Genetic Investigation of Anthropometric Traits (GIANT) Consortium, the Tobacco and Genetics (TAG) Consortium, and the Social Science Genetic Association Consortium (SSGAC), as well as meta-analysis results from a T1D genome-wide association study.

CONCLUSIONS

This study provides genetic support for a link between childhood adiposity and T1D risk. Together with evidence from observational studies, our findings further emphasize the importance of measures to reduce the global epidemic of childhood obesity and encourage mechanistic studies.

Investigating the link between drug-naive first episode psychoses (FEPs), weight gain abnormalities and brain structural damages: Relevance and implications for therapy

Evidence suggests that obesity and overweight may be associated with severe brain structural abnormalities and poor cognitive and functional outcomes in the general population. Despite these observations and the high prevalence of weight gain abnormalities in patients with psychosis spectrum disorders (PSDs), no studies have investigated the impact that these metabolic disturbances may have on brain structures and development in the earliest stages of PSDs. In the present review we shed light on the association between weight gain and brain structural abnormalities that may affect the course of illness in drug-naïve FEPs. Given the lack of studies directly investigating this issue, we firstly identified and critically evaluated the literature assessing weight gain abnormalities and gray or white matter (GM, WM) volumes (either globally or in specific regions of interest) in otherwise healthy obese/overweight adolescents and young adults. We then compared the results of this systematic review with those of two recent meta-analysis investigating GM and WM abnormalities in drug-naïve FEPs. Weight gain in otherwise healthy subjects was consistently associated with frontal and temporal GM atrophy and with reduced integrity of WM in the corpus callosum. Of relevance, all these brain regions are affected in drug-naïve FEPs, and their integrity is associated with clinical, cognitive and functional outcomes. The underlying mechanisms that may explain the association between weight gain, adiposity, and brain damage in both healthy subjects and drug-naïve FEPs are widely discussed. On the basis of this knowledge, we tried: a) to deduce an integrative model for the development of obesity in psychosis spectrum disorders; b) to identify the key vulnerability factors underlying the association between weight gain and psychosis; c) to provide information on new potential targets of intervention.

Postload hyperglycemia is associated with increased subclinical inflammation in patients with prediabetes

BACKGROUND/AIMS

In this present study, we aimed: (i) To clarify if prediabetes is associated with subclinical inflammation independent of underlying obesity, and (ii) to evaluate the effect of postload glucose concentration on subclinical inflammation markers in a group of patients with elevated fasting glucose.

MATERIAL AND METHODS

In a cohort of 165 patients with newly detected fasting hyperglycemia, according to 75 g oral glucose tolerance test (OGTT), subjects were classified either as newly diagnosed type 2 diabetes (diabetes group, n = 40), impaired fasting glucose (IFG) plus impaired glucose tolerance (IGT) (IFG/IGT group, n = 42) or IFG only (IFG group, n = 83). A control group (n = 47) consisted of age- and body mass index (BMI)-matched healthy subjects with a normal OGTT. Circulating concentrations of lipids, insulin, interleukin-6 (IL-6), interleukin-8 (IL-8) and high sensitive C-reactive protein (hsCRP) were measured. HOMA index was calculated.

RESULTS

Subclinical inflammation markers were elevated in patients with diabetes and IFG/IGT compared to healthy controls and also IFG patients (diabetes vs. control: p < 0.05 for hsCRP, IL-8, and IL-6; IFG/IGT vs. control: p < 0.05 for hsCRP, and IL-6; diabetes vs. IFG: p < 0.05 for hsCRP, and IL-6; IFG/IGT vs. IFG: p < 0.05 for hsCRP, and IL-6). In multiple regression analysis, postload glucose concentration was independently associated with circulating hsCRP and IL-6 concentrations when the data was controlled for age, gender, BMI and lipid concentrations (p < 0.05 for hsCRP, and IL-6).

CONCLUSION

Our results suggest that patients with prediabetes, independent of underlying obesity, have increased concentrations of subclinical inflammation which is mostly driven by postload glucose concentrations.

Cardiovascular disease in childhood: the role of obesity

In recent years, childhood obesity is becoming an epidemic health problem. It is now evident from many studies that childhood obesity is correlated with adult excess weight status and the development of risk factors for cardiovascular diseases in adulthood, including hypertension, type 2 diabetes mellitus, dyslipidemia, and metabolic syndrome. The exposure to obesity and to the above risk factors during childhood subsequently lead to atherosclerotic development, such as altered vascular structure and function, although the mechanisms are still unclear. Several non-invasive, and thus easy-to-obtain measures of arterial structure and function, have been shown to be clinically useful in providing information about vasculature early in the course of atherosclerosis, including measurement of endothelial function, carotid intima media thickness, and arterial stiffness. The early detection of cardiovascular abnormalities is essential because the control of the atherogenic process is more effective during its early stages. The present review focuses on the cardiovascular consequences of obesity, on the mechanisms and the methods of measurement of endothelial dysfunction in obese children and adolescents, and on the ways of intervention for the improvement of vascular health.

[Adipokines in healthy and obese children]

The worldwide increase in the prevalence of obesity in children and adolescents during the last decades, as well as the mounting evidence indicating that obesity is associated with an increased incidence of comorbidities and the risk of premature death, resulting in a high economic impact, has stimulated obesity focused research. These studies have highlighted the prominent endocrine activity of adipose tissue, which is exerted through the synthesis and secretion of a wide variety of peptides and cytokines, called adipokines. This review presents a summary of the current knowledge and most relevant studies of adipokine dynamics and actions in children, focusing on the control of energy homeostasis, metabolic regulation (particularly carbohydrate metabolism), and inflammation. The particularities of adipose secretion and actions in healthy children, from birth to adolescence, and the modifications induced by early onset obesity are highlighted.

Adipokines in childhood obesity

The worldwide increase in the prevalence of obesity in children and adolescents during the past decades, in addition to mounting evidence indicating that obesity is associated with an increased incidence of comorbidities and the risk of premature death, resulting in a high economical impact, has stimulated obesity-focused research. These studies have highlightened the prominent endocrine activity of adipose tissue, which is exerted through the synthesis and secretion of a wide variety of peptides and cytokines, called adipokines. In the present review, we have summarized the current knowledge and most relevant studies of adipokine dynamics and actions in children, focusing on the control of energy homeostasis, metabolic regulation (particularly, carbohydrate metabolism), and inflammation. The particularities of adipose secretion and actions in healthy children, from birth to adolescence, and the modifications induced by early-onset obesity are highlighted.

Elevated glucose level at 30 minutes during an oral glucose tolerance test in obese adolescents: a new disorder of glucose tolerance

We observed glucose levels >140 mg/dL measured at 30 minutes (min) during an oral glucose tolerance test (OGTT) in some obese patients. We aimed to investigate the significance of this finding by comparing lipid profiles, insulin resistance indices, and systemic inflammatory mediators between obese adolescents with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and elevated glucose levels at 30 min. The study involved 80 obese (body mass index >95(th) percentile for age and sex) adolescents (48 female, 32 male) between 11 and 16 years of age. Depending on OGTT results, patients were divided into NGT and IGT groups. The third group was recruited from the NGT group as having glucose levels > 140 mg/dL at 30 minutes. Lipid profiles, [interleukin-6 (IL-6)], neopterin, and lipoprotein associated phospholipase A₂ (Lp-PLA₂)] were assessed. Neopterin and Lp-PLA₂ levels were significantly higher in obese adolescents with elevated glucose levels at 30 min. compared with those in both NGT and IGT groups (p=0.013, and 0.004, respectively). In these adolescents, IL-6 levels were significantly higher only than the NGT group (p=0.01). In logistic regression analysis, IL-6, neopterin and Lp-PLA₂ levels were detected to be related to high blood glucose levels at 30 min (OR 1.11, p=0.01; OR 9.03, p=0.013; OR 1.01, p=0.004 respectively). Obese adolescents with elevated glucose levels at 30 min. demonstrated higher inflammatory mediators levels, which were atherosclerotic indicators, than obese adolescents with NGT and IGT. These results suggest that glucose levels >140 mg/dL measured at 30 min during an OGTT may be a new disorder of glucose tolerance in obesity.

Inflammatory and prothrombotic states in obese children of European descent

Adipose tissue may release mediators that induce a chronic inflammatory state and alterations in coagulation, which contribute to insulin resistance, atherosclerosis, and thrombosis. We investigated whether inflammatory and/or prothrombotic states exist in obese children and assessed their interrelationship. Sixty-one subjects were recruited, aged between 6 and 16 years, to participate in a cross-sectional study at Children's University Hospital of Geneva. Selected pro/anti-inflammatory cytokines/chemokines and hemostasis parameters were measured in obese children and lean controls. Cardiovascular risk factors in the family were indexed. Fasting glucose level, insulin, prothrombin time (PT), fibrinogen, activated partial thromboplastin time (aPTT), D-dimer, endogenous thrombin potential (ETP), C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-10 (IL-10), interferon-γ-inducible-protein (IP-10), monocyte chemoattractant protein 1 (MCP-1), and interleukin-1 receptor antagonist (IL-1Ra) were measured. We estimated insulin resistance by homeostatic model assessment (HOMA). Anti- (IL-1Ra) and proinflammatory cytokines (MCP-1, IL-6) were significantly increased in obese children in comparison to the control group, even before puberty. Hemostasis was also altered in obese children with a significantly increased fibrinogen level, increased D-dimer, a shortened PT, as well as an increased ETP. No correlation was found between cytokine levels and hemostasis parameters, except for IL-6 and fibrinogen. Obese children present with inflammatory and prothrombotic states as early as 6 years of age and these states are similar in prepubertal and pubertal obese children. The cytokines IL-1Ra and MCP-1 were most significantly increased in obese children. Further investigation is necessary to determine if these cytokines, together with ETP, can reliably predict the development of diabetes and atherosclerosis.

Circulating pro-inflammatory cytokines and adiponectin in young men with type 2 diabetes

This study was designed to investigate plasma circulating pro-inflammatory cytokines, adiponectin and high-sensitive C-reactive protein (hsCRP) in young men with type 2 diabetes. New-onset young men with type 2 diabetes (young diabetes, YDM; age between 10 and 25) were recruited and divided into a non-obese group (NOYDM, body mass index, BMI ≦ 25 kg/m(2), N = 23) and an obese group (OBYDM, BMI ≧ 25 kg/m(2), N = 24). Twenty-four non-obese non-diabetic young men served as controls. Hemoglobin A1c, fasting glycemic index, lipids, adiponectin, hsCRP, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined. Insulin sensitivity and β-cell function were calculated using the homeostasis model assessment method (HOMA-IR and HOMA-β, respectively). Compared to controls, significantly greater HOMA-IR (7.9 ± 1.9 and 10.4 ± 2.5 vs. 1.5 ± 0.3, P < 0.001) and fasting insulin (103.3 ± 21.1 and 209.9 ± 24.4 vs. 48.5 ± 6.7 pmol/l, P < 0.01 and P < 0.001, respectively) were observed in NOYDM and OBYDM. There were significantly lower plasma adiponectin and higher hsCRP and TNF-α levels in OBYDM, whereas higher TNF-α and IL-6 were shown in NOYDM. Spearman rank correlation analysis demonstrated significant correlations between BMI and adiponectin (R = -0.44, P < 0.005), CRP (R = 0.28, P < 0.05), TNF-α (R = 0.42, P < 0.005) and IL-6 (R = 0.33, P < 0.01) in all YDM. Among measured cytokines, only adiponectin was significantly correlated with HOMA-IR, this correlation was abolished when adjusted for age and BMI (R = -0.24, P = 0.12). YDM not only exhibits insulin resistance, but also has inflammatory and atherogenic properties. BMI might be a major determinant of those markers.

[Obesity-related metabolic disorders in childhood and adolescence]

Obesity is the most frequent nutritional disorder in childhood and adolescence. The rise in its prevalence and severity has underlined the numerous and significant obesity-related metabolic disorders. Altered glucose metabolism, manifested as impaired glucose tolerance, appears early in severely obese children and adolescents. Obese young people with glucose intolerance are characterized by marked peripheral insulin resistance and relative beta-cell failure. Lipid deposition in muscle and the visceral compartment, and not only obesity per se, is related to increased peripheral insulin resistance, the triggering factor of the metabolic syndrome. Other elements of the metabolic syndrome, such as dyslipidaemia, and hypertension, are already present in obese youngsters and worsen with the degree of obesity. The long-term impact of obesity-related insulin resistance on cardiovascular morbidity in these patients is expected to emerge as these youngsters become young adults.

Hormones and cytokines in childhood obesity

OBJECTIVE

Obesity is a growing worldwide health problem affecting both adults and children. Effective prevention and treatment modalities can be achieved by understanding the pathogenesis of obesity better. This review addresses some of the issues related to the hormones and cytokines taking part in the pathogenesis of obesity, energy balance and inflammation.

DESIGN

We reviewed current literature on this broad subject especially concentrating on the functions of the hormones and cytokines taking part in the pathogenesis of the childhood obesity. Using the key words obesity, children, hormones, cytokines publications and cross references were evaluated from PubMed database between 1957 and 2009.

RESULTS

In children, leptin and ghrelin are two hormones which have major influence on energy balance. Leptin is responsible from long term regulation of energy balance and ghrelin functions as an appetite stimulatory signal. In contrast to ghrelin, obestatin acts as an anorexigenic hormone by suppressing food intake. Adipokines secreted from adipose tissue are the key regulators of inflammation in obesity. Increased TNF-alpha and IL-6 levels but decreased levels of adiponectin and IL-10 are associated with increased inflammation, tissue injury and complications of obesity.

CONCLUSIONS

Development, pathogenesis and complications of childhood obesity consist of complex mechanisms including numerous cytokines and hormones. New treatment modalities depend on understanding these complex mechanisms.

Obesity and low-grade inflammation: a paediatric perspective

Childhood obesity is a major public health problem. Low-grade inflammation, a hallmark characterizing adult obesity, may be a pivotal mechanism linking obesity to its numerous systemic complications, with adipose tissue depots secreting and producing inflammatory mediators and visceral fat displaying an increased inflammatory profile. While knowledge is relatively scarce regarding the importance of the adipose tissue inflammation process in children, identifying its contribution in childhood obesity and the associated influences of age, sex, weight status, growth, and adipose depot phenotypes are crucial for understanding physiopathology and implementing early intervention strategies. We review the latest research linking obesity and inflammation in childhood focusing on serum inflammatory markers and the effectiveness of lifestyle interventions in improving systemic inflammation. Generally, there are significant correlations between body mass index and increased c-reactive protein and decreased adiponectin levels in children; these levels tend to be improved in interventions resulting in approximately 5% weight loss, regardless of the type or length of intervention. There is a need for further research measuring other inflammatory mediators (e.g. tumour necrosis factor (TNF)-alpha, IL-6, IL-8) and histological studies examining immune cell infiltration in adipose tissue depots in obese children.

The exon 3-deleted/full-length growth hormone receptor polymorphism does not influence the effect of puberty or growth hormone therapy on glucose homeostasis in short non-growth hormone-deficient small-for-gestational-age children: results from a two-year controlled prospective study

CONTEXT

The exon 3-deleted/full-length (d3/fl) GH receptor polymorphism (d3/fl-GHR) has been associated with responsiveness to GH therapy in short small-for-gestational-age (SGA) patients, although consensus is lacking. However, its influence on glucose homeostasis, at baseline or under GH therapy, has not been investigated.

OBJECTIVE

Our objective was to evaluate whether the d3/fl-GHR genotypes influence insulin sensitivity in short SGA children before or after puberty onset or during GH therapy.

DESIGN

We conducted a 2-yr prospective, controlled, randomized trial.

SETTING

Thirty Spanish hospitals participated. Auxological, GH secretion, and glucose homeostasis evaluation was hospital based, whereas molecular analyses and data computation were centralized.

PATIENTS

Patients included 219 short SGA children [body mass index sd score (SDS) < or = 2.0]; 159 were prepubertal (group 1), and 60 had entered puberty (group 2).

INTERVENTION

Seventy-eight patients from group 1 were treated with GH (66 microg/kg.d) for 2 yr (group 3).

MAIN OUTCOME MEASURES

Previous and 2-yr follow-up auxological and biochemical data were recorded, d3/fl-GHR genotypes determined, and data analyzed.

RESULTS

In groups 1 and 2, fasting glucose, insulin, homeostasis model assessment (HOMA), and quantitative insulin sensitivity check index (QUICKI) were similar in each d3/fl-GHR genotype. Group 2 glucose, insulin, and HOMA were significantly higher and QUICKI lower than in group 1. In group 3 GH-treated patients, height SDS, growth velocity SDS, fasting glucose, insulin, and HOMA significantly increased as did body mass index SDS at the end of the second year, and QUICKI decreased during the first and second years, with no differences among the d3/fl-GHR genotypes.

CONCLUSION

In short SGA patients, the d3/fl-GHR genotypes do not seem to influence prepubertal or pubertal insulin sensitivity indexes or their changes over 2 yr of GH therapy (66 mug/kg.d).

Glucose intolerance and diabetes are observed in the long-term follow-up of nonpancreatectomized patients with persistent hyperinsulinemic hypoglycemia of infancy due to mutations in the ABCC8 gene

OBJECTIVE

To report the long-term follow-up of three nonpancreatectomized patients with persistent hyperinsulinemic hypoglycemia of infancy due to mutations in the ABCC8 gene.

RESEARCH DESIGN AND METHODS

Oral glucose tolerance test (OGTT) and venous 24-h glucose-insulin profile were performed yearly from adolescence.

RESULTS

Patient 1 (now aged 31 years) developed insulin-dependent diabetes at the age of 25 years. In patient 2 (now aged 17 years), impaired fasting glucose and a diabetic OGTT response with normal A1C values have been observed since the age of 10 years. In patient 3 (now aged 24 years), intolerant OGTT response and hyperglycemic episodes with normal A1C have been observed since the age of 16 years. All patients presented relatively low insulin levels during hyperglycemia, normal BMI, and negative autoantibodies (GAD antibody, insulinoma-associated protein 2, and islet cell antibody).

CONCLUSIONS

Development of glucose metabolism impairment ranging from glucose intolerance to insulin-dependent diabetes is observed in the evolution of these patients.

Low-grade inflammation and the metabolic syndrome in children and adolescents

PURPOSE OF REVIEW

The prevalence of overweight and the metabolic syndrome is increasing in young people. This review aims to summarize current research in children and adolescents on inflammatory markers related to components of the metabolic syndrome.

RECENT FINDINGS

Obesity is characterized by a state of low-grade inflammation at all ages. Body fat has been shown to correlate with the various components of the metabolic syndrome. There is evidence to show that chronic subclinical inflammation in childhood and adolescence is associated with metabolic dysfunction, which can lead to insulin resistance and the metabolic syndrome.

SUMMARY

The results presented in this review highlight the underlying inflammatory mechanisms of the early stages of metabolic disorders related to obesity. The preclinical phases of diabetes and cardiovascular disease last many decades, and this feature of the diseases provides an opportunity for the early identification of target groups and the use of appropriate prevention strategies while the pathological processes are still completely reversible.

Low-grade inflammation, obesity, and insulin resistance in adolescents

CONTEXT

Low-grade inflammation is associated with insulin resistance and precedes the onset of type 2 diabetes mellitus in adults, but there are no comparable data in youth.

OBJECTIVE

The objective of the study was to characterize the pattern of subclinical immune activation that is associated with indices of obesity and insulin resistance in youth and analyze whether this association is explained by obesity.

DESIGN

This was a cross-sectional study.

SETTING

Medical check-up of schoolchildren was conducted by the Public Health Office in Düsseldorf (Germany).

PARTICIPANTS

Participants included 519 adolescents (mean age 15.5 +/- 0.8 yr).

MAIN OUTCOME MEASURES

Measures included body mass index (BMI) and waist circumference (WC) as indices of obesity; fasting glucose, insulin, and homeostasis model assessment of insulin resistance; serum concentrations of TNFalpha, IL-6, IL-8, IL-18, monocyte chemoattractant protein-1, interferon-gamma-inducible protein (IP)-10 and adiponectin as immunological variables.

RESULTS

In age-, sex-, and lipid-adjusted analyses, IL-6, IL-18, IP-10, and adiponectin (inversely) were associated with both BMI and WC (all P <or= 0.002). None of the immune markers was related to glucose, but IL-6, IL-18, and adiponectin (inversely) were associated with insulin and homeostasis model assessment of insulin resistance in age- and sex-adjusted models. Adjustment for BMI or WC indicated that a considerable proportion of these associations may be mediated by obesity.

CONCLUSIONS

We found that a differential low-grade immune activation is associated with parameters of obesity in adolescents. Moreover, there is evidence that IL-6, IL-18, IP-10, and adiponectin (inversely) are associated with insulin resistance and that these associations can mainly be attributed to obesity.