Identification and treatment of metabolic complications in pediatric obesity

Metabolic Consequences of Pediatric Obesity: A Review of Pathophysiology, Screening, and Treatment

The prevalence of pediatric obesity has been increasing during the last 30 years, and the subsequent metabolic consequences of obesity, which were mainly seen in adults, are now presenting in childhood. Type 2 diabetes, prediabetes, metabolic syndrome, and nonalcoholic fatty liver disease are serious metabolic ramifications of pediatric obesity; pediatricians need to be familiar in screening and treatment of these metabolic issues. This review will discuss the inflammation and insulin resistance involved in obesity that can lead to these conditions. We will explore the pathophysiology of type 2 diabetes and prediabetes, metabolic syndrome, and nonalcoholic fatty liver disease and review screening and treatment modalities. Finally, we will highlight other important endocrine related comorbidities in pediatric obesity, including polycystic ovary syndrome, precocious puberty, and early accelerated growth. [Pediatr Ann. 2023;52(2):e62-e67.].

The Emerging Role of Sfrp5 and Wnt5a in the Pathogenesis of Obesity: Implications for a Healthy Diet and Lifestyle

In recent decades, the prevalence of obesity has risen dramatically worldwide among all age groups. Obesity is characterized by excess fat accumulation and chronic low-grade inflammation. The adipose tissue functions as a metabolically active endocrine organ secreting adipokines. A novel duo of adipokines, the anti-inflammatory secreted frizzled-related protein 5 (Sfrp5) and the proinflammatory wingless type mouse mammary tumor virus (MMTV) integration site family member 5A (Wnt5a), signal via the non-canonical Wnt pathway. Recent evidence suggests that Sfpr5 and Wnt5a play a key role in the pathogenesis of obesity and its metabolic complications. This review summarizes the current knowledge on the novel regulatory system of anti-inflammatory Sfrp5 and pro-inflammatory Wnt5a, and their relation to obesity and obesity-related complications. Future studies are required to investigate the potential role of Sfrp5 and Wnt5a as biomarkers for monitoring the response to lifestyle interventions and for predicting the development of cardiometabolic risk factors. These adipokines may also serve as novel therapeutic targets for obesity-related disorders.

Secreted frizzled-related protein 4 promotes brown adipocyte differentiation

Secreted frizzled-related protein 4 (SFRP4) is a member of the SFRP family that contains a cysteine-rich domain homologous to the putative Wnt-binding site of frizzled proteins. In the present report, the effects of SFRP4 on murine brown adipocyte differentiation were evaluated, which exhibited an intrinsic capacity to differentiate with high efficiency. Brown preadipocytes were isolated from the scapular region of brown adipose tissue, which showed that the overexpression of recombinant active SFRP4 protein at three concentrations (1, 10 and 100 ng/ml) significantly increased the expression of adipocyte differentiation-associated genes (C/EBPα, C/EBPβ, UCP-1, PRDM16, PGC1α and GLUT4) in a dose-dependent manner compared with the control group. Secondly, adiponectin protein expression was significantly inhibited in a dose-independent manner, while leptin was increased in brown adipocytes by incubation with the high concentration (100 ng/ml) of SFRP4. Thirdly, the role of interleukin-1β (IL-1β) was investigated in brown adipocytes and discovered that IL-1β cannot induce SFRP4 mRNA expression in brown adipocytes, similar to human islet cells. These data suggested that SFRP4-treated brown adipocytes represent a valuable in vitro model for the study of adipogenesis and indicated that SFRP4 served various functions during brown adipocyte differentiation.

Nonalcoholic fatty liver disease, insulin resistance, and sweeteners: a literature review

Introduction: Sweeteners are substances used to replace sugar. They can either be chemically produced (artificial sweeteners) or extracted from plants (natural sweeteners). In the last two decades, there is an increased popularity in their role as sugar substitutes in individuals to promote weight loss or maintain glycemic control. However, despite their favorable effects, there is concern regarding their side effects and especially their influence in the development of nonalcoholic fatty liver disease (NAFLD).Areas covered: A comprehensive literature search was conducted on Medline including systematic reviews, longitudinal controlled studies, and retrospective cohort studies. We present an up-to-date systematic review of the current literature regarding the safety in artificial and natural sweeteners use as a means of weight loss or diabetes control.Expert opinion: Natural sweeteners have not been associated directly with NAFLD, and on the contrary, some, such as stevia, and trehalose, may have a protective effect. Rare sugars and polyols can be used safely and have significant benefits that include anti-oxidant effect and optimal glycemic control. Artificial sweeteners, due to their effect on NAFLD development and insulin resistance, are not indicated in patients with obesity or diabetes. Further studies in human subjects are required to verify the above findings.

Obesity in Adolescents with Psychiatric Disorders

PURPOSE OF REVIEW

This narrative review synthesized recent research related to obesity in adolescents with psychiatric disorders, with a focus on epidemiology, mechanisms, and weight management approaches. The paper reviews literature on depressive and anxiety disorders, bipolar disorder, and schizophrenia spectrum and other psychotic disorders.

RECENT FINDINGS

Depression has a bidirectional relationship with obesity. Bipolar disorder and schizophrenia spectrum disorders, and their treatments, increase the risk of developing obesity. Mechanisms underlying this weight gain include lifestyle and environmental factors and psychiatric medications, though emerging evidence has also suggested the role of genetic and neuroendocrine processes. Evidence about the most effective treatments for obesity in adolescents with psychiatric disorders remains limited. Adolescents with psychiatric disorders are at high risk for obesity. Close monitoring for increases in weight and cardiometabolic risk factors with use of antipsychotic and mood-stabilizing medications is recommended. Clinical trials are needed that test the efficacy of weight management strategies for this population.

Evaluation of DNA damage profile in obese women and its association to risk of metabolic syndrome, polycystic ovary syndrome and recurrent preeclampsia

Metabolic syndrome (MS) is a cluster of metabolic abnormalities. Obesity and MS are always accompanied by elevated oxidative stress which might affect cellular bio-molecules such as DNA. The aim of the present study is to investigate DNA damage profile in obese premenopausal women and its relation to the risk of MS, polycystic ovary syndrome (PCOS) and history of recurrent pre-eclampsia. The study included 90 obese women included cases with MS (n = 30), PCOS (n = 30) and previous history of recurrent preeclampsia (n = 30) and, age-matched healthy non-obese control women (n = 50). The assessment of leukocyte DNA damage was done by comet assay for all cases and controls. Anthropometry and biochemical parameters have been measured. Results showed that mean percent of DNA damage was significantly higher in MS, PCOS as well as in women with the recurrent preeclampsia as compared to healthy controls. The high level of mean DNA damage frequency in obese women was significantly associated with the increased number of metabolic syndrome components. Cases with 2, 3 and 3-5 components showed significantly higher levels of DNA damage than controls. Moreover, cases with 3-5 MS components showed significant higher DNA compared to those with the two components. Regarding PCOS, significant positive association between the mean frequency of DNA damage and waist circumference was observed. The study suggests that metabolic abnormalities, PCOS and recurrent pre-eclampsia might be contributed in development of DNA damage in obese women. DNA damage can serve as an early marker for obesity complications in premenopausal women.

The safety of pharmacologic treatment for pediatric obesity

INTRODUCTION

Pediatric obesity is a serious public health concern. Five medications have been approved by the Food and Drug Administration (FDA) for chronic weight management in adults with obesity, when used as an adjunct to lifestyle modification. Orlistat is the only FDA-approved medication for pediatric patients aged 12 years and above.

AREAS COVERED

This paper summarizes safety and efficacy data from clinical trials of weight loss medications conducted among pediatric samples. Relevant studies were identified through searches in PubMed.

EXPERT OPINION

Orlistat, as an adjunct to lifestyle modification, results in modest weight losses and may be beneficial for some pediatric patients with obesity. However, gastrointestinal side effects are common and may limit use. In adults taking orlistat, rare but severe adverse events, including liver and renal events, have been reported. Recent pediatric pharmacokinetic studies of liraglutide have demonstrated similar safety and tolerability profiles as found in adults, with gastrointestinal disorders being the most common adverse events. Clinical trials are needed of liraglutide, as well as other medications for obesity, that systematically evaluate their risks and benefits in pediatric patients.

Serum glypican 4 level in obese children and its relation to degree of obesity

OBJECTIVE

Previous adult studies have demonstrated associations of serum glypican 4 (Gpc4) and obesity parameters and insulin sensitivity. However, an association of serum Gpc4 and glucose metabolism remains contradictory. Study of serum Gpc4 in obese children has not been conducted. We aimed to determine serum Gpc4 levels in obese children with various degrees of obesity.

DESIGN, PATIENTS AND MEASUREMENTS

Up to 370 overweight and obese children, aged 6-18 years were enrolled in this cross-sectional study. Oral glucose tolerance test (OGTT) was performed with fasting serum Gpc4, lipid profiles, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) measured. Insulin sensitivity and β-cell function indices were calculated from plasma glucose and serum insulin levels derived from the OGTT. Bioelectrical impedance analysis was performed for body fat determination. Comparisons of serum Gpc4 levels among the groups of children with various degrees of obesity were performed.

RESULTS

Serum Gpc4 levels progressively increased in children with increasing body mass index standard deviation score (BMI SDS) tertiles [median (interquartile range, IQR): 2.3 (1.8, 3.2), 2.6 (1.9, 3.4) and 3.2 (2.4, 3.8) μg/L, P<.001]. There were no differences in serum Gpc4 levels among children in the different glucose metabolism categories. Log serum Gpc4 levels were positively correlated with SDSs of weight and BMI, cholesterol, AST and ALT. No associations of log serum Gpc4 and insulin sensitivity and β-cell function indices were demonstrated.

CONCLUSIONS

Serum Gpc4 levels were increased with increasing degrees of obesity. There were no differences in serum Gpc4 levels among glucose metabolism categories.

Who seeks bariatric surgery? Psychosocial functioning among adolescent candidates, other treatment-seeking adolescents with obesity and healthy controls

Limited data are available on the characteristics of adolescents with obesity who seek bariatric surgery. Existing data suggest that adolescent surgery candidates have a higher body mass index (BMI) than comparison adolescents with obesity, but the limited findings regarding psychosocial functioning are mixed. This study aimed to compare BMI and psychosocial functioning among adolescent bariatric surgery candidates, outpatient medical-treatment-seeking adolescents with obesity (receiving lifestyle modification), and adolescents in the normal-weight range. All adolescents completed self-report measures of impulsivity, delay discounting, depression, anxiety, stress, eating pathology, family functioning and quality of life, and had their height and weight measured. Adolescent surgical candidates had higher BMIs than both comparison groups. Surgical candidates did not differ from medical-treatment-seeking adolescents with obesity on any measure of psychosocial functioning, but both groups of adolescents with obesity reported greater anxiety and eating pathology and poorer quality of life than normal-weight adolescents. Quality of life no longer differed across groups after controlling for BMI, suggesting that it is highly related to weight status. Adolescents with obesity may experience greater anxiety, eating pathology, and quality of life impairments than their peers in the normal-weight range regardless of whether they are seeking surgery or outpatient medical treatment. Clinical implications and directions for future research are discussed.

Metabolic syndrome's risk factors and its association with nutritional status in schoolchildren

The metabolic risk factors (RF) to the diagnosis of metabolic syndrome (MetS) have been evidenced at early ages, including children. The aim of the present study was to identify the prevalence of RF to the diagnosis of MetS and its association with nutritional status of schoolchildren from 6 to 10 years old. A cross-sectional study was carried out in 505 students of municipal schools in Macae, Brazil, conducted from 2013 to 2014. The RF evaluated were: blood pressure (mm Hg), triglycerides (mmol/L), HDL-cholesterol (mmol/L) fasting glucose (mmol/L) and waist circumference (cm). At least one RF was present in 61% (n = 308) of the sample. By nutritional status, there was higher prevalence of RF in overweight/obese schoolchildren compared to those with normal weight, except in the concentration of HDL-c. The prevalence of one, two and three RF (MetS) were 34.7% (n = 175), 21.0% (n = 106) and 5.3% (n = 27), respectively. Two RF were more present in overweight (28.2% 95%CI 19.0; 39.0) and obese (41.5% 95%CI 31.4; 52.1) compared to normal weight children (13.5% 95%CI 9.9; 17.8). Three or more RF were more frequent among obese (25.5% 95%CI 17.0; 35.5) in relation to overweight (2.4% 95%CI 0.2; 8.2) and normal weight children (0.3% 95%CI 0; 1.7). The data indicate high prevalence of RF and its relationship with the magnitude of body weight excess. Therefore, the identification and early treatment of these RF might minimize the risk of MetS and related diseases.

Wnt3a regulates mitochondrial biogenesis through p38/CREB pathway

Wnt3a is established as an important regulator of various developmental processes, especially in osteogenesis, adipogenesis and mitochondrial biogenesis. Numerous studies reported Wnt3a regulates osteogenesis and adipogenesis, but the mechanisms by which Wnt3a regulates mitochondrial biogenesis are not well understood. In this study, results suggested that Wnt3a stimulates mitochondrial biogenesis by increasing the expression of mitochondrial biogenesis genes and regulators, as well as mitochondrial copy number in adipocytes. As a key mediator of canonical Wnt/β-catenin pathway, β-catenin knockdown had no effect on basal or Wnt3a-mediated mitochondrial biogenesis in adipocytes, which suggested that Wnt3a-mediated mitochondrial biogenesis was independent of β-catenin-dependent canonical Wnt/β-catenin pathway. However, Wnt3a inhibited p38/CREB (p38 mitogen-activated protein kinase/cAMP response element-binding protein) signaling activation and p38 inhibitor impaired Wnt3a-stimulated mitochondrial biogenesis, indicating p38/CREB pathway could be involved in the regulation of Wnt3a-mediated mitochondrial biogenesis in adipocytes. In conclusion, our data showed that Wnt3a stimulates mitochondrial biogenesis in adipocytes, which is at least partially through activation of p38/CREB pathway.

Regulation of Adipogenesis by Quinine through the ERK/S6 Pathway

Quinine is a bitter tasting compound that is involved in the regulation of body weight as demonstrated in in vivo animal models and in vitro models of the adipogenic system. Arguments exist over the positive or negative roles of quinine in both in vivo animal models and in vitro cell models, which motivates us to further investigate the functions of quinine in the in vitro adipogenic system. To clarify the regulatory functions of quinine in adipogenesis, mouse primary preadipocytes were induced for differentiation with quinine supplementation. The results showed that quinine enhanced adipogenesis in a dose dependent manner without affecting lipolysis. The pro-adipogenic effect of quinine was specific, as other bitter tasting agonists had no effect on adipogenesis. Moreover, the pro-adipogenic effect of quinine was mediated by activation of ERK/S6 (extracellular-signal-regulated kinase/Ribosomal protein S6) signaling. Knockdown of bitter taste receptor T2R106 (taste receptor, type 2, member 106) impaired the pro-adipogenic effect of quinine and suppressed the activation of ERK/S6 signaling. Taken together, quinine stimulates adipogenesis through ERK/S6 signaling, which at least partly functions via T2R106.

Association of Urinary Sodium Excretion With Insulin Resistance in Korean Adolescents: Results From the Korea National Health and Nutrition Examination Survey 2009-2010

High sodium intake is a well-known risk factor for elevated blood pressure and is responsible for a higher incidence of cardiovascular events. Reports have suggested an association of sodium intake with insulin resistance (IR) and type 2 diabetes mellitus in adults. However, evidence on an association between sodium intake assessed on the basis of urinary sodium excretion and IR in adolescents is scarce. The present study aimed at investigating the association between urinary sodium excretion and IR among South Korean adolescents.This population-based, cross-sectional study analyzed the data obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) 2009 to 2010. The data of a total of 1353 adolescents (779 boys and 574 girls) were included in the final analysis. Spot urine samples were collected, and urinary sodium excretion was estimated by using the urinary sodium concentration (U[Na]), U[Na] to urinary creatinine ratio (U[Na]/Cr), and U[Na] to specific gravity unit (SGU) ratio (U[Na]/SGU). IR was assessed by using the homeostasis model assessment of IR (HOMA-IR). Hierarchical multivariable logistic regression analysis was performed to assess the risk for a high HOMA-IR according to urinary sodium excretion.The mean levels of U[Na], U[Na]/Cr, and U[Na]/SGU were significantly higher in subjects in the highest HOMA-IR quartile (Q4) than in subjects in the lowest, second, or third quartiles (Q1-3) of HOMA-IR. The mean values of HOMA-IR and several cardiometabolic parameters tended to progressively increase with the U[Na], U[Na]/Cr, and U[Na]/SGU quartiles. Q3 of U[Na] was at a significantly higher risk than Q1 of U[Na] of an association with Q4 of HOMA-IR, after adjustment for confounding variables. Q3 and Q4 of U[Na]/Cr and U[Na]/SGU, respectively, had significantly higher risks, than the respective Q1s, of an association with Q4 of HOMA-IR. The risk of an association with Q4 of HOMA-IR demonstrated significantly increasing trends with increasing quartiles of U[Na], U[Na]/Cr, and U[Na]/SGU irrespective of confounding factors.Urinary sodium excretion was positively associated with IR in South Korean adolescents. The monitoring and control of urinary sodium excretion may be recommended as an important intervention for the prevention of IR and related diseases in adolescents.

Serum fibroblast growth factor 21 in overweight and obese Thai children and adolescents: its relation to glucose metabolism and its change after glucose loading

OBJECTIVES

Fibroblast growth factor 21 (FGF21) has been demonstrated to be beneficial for glucose metabolism in animal and in vitro studies. However, its role in humans is still unclear. This study aimed to determine serum FGF21 in relation to glucose metabolism in obese children and to evaluate serum FGF21 changes during an oral glucose tolerance test (OGTT).

DESIGN, PATIENTS AND MEASUREMENTS

A cross-sectional study of 301 obese children was conducted in a tertiary hospital. All children underwent an OGTT and had their fasting serum FGF21 and adiponectin measured. A subgroup of 71 children had their serum FGF21 levels serially measured at 0, 60 and 120 min during the OGTT.

RESULTS

Serum FGF21 levels were progressively increased in children with normal glucose tolerance without hyperinsulinaemia, normal glucose tolerance with hyperinsulinaemia and abnormal glucose tolerance [median (IQR): 72 (34-148), 96 (55-182), 122 (75-220) pg/ml, respectively, P = 0·003]. Log serum FGF21 was associated with homoeostatic model assessment of insulin resistance (r = 0·174, P = 0·002). There was no correlation between log serum FGF21 and serum adiponectin level. During the OGTT, there were changes in serum FGF21 levels with a decrease in FGF21 at 60 min from the baseline and an increase above the baseline at 120 min.

CONCLUSIONS

Serum FGF21 level was highest in obese children with the highest insulin resistance or abnormal glucose tolerance. Log serum FGF21 was not correlated with serum adiponectin. Changes in serum FGF21 levels during the OGTT were observed.

Population-Based Studies on the Epidemiology of Insulin Resistance in Children

BACKGROUND

In view of the alarming incidence of obesity in children, insight into the epidemiology of the prediabetic state insulin resistance (IR) seems important. Therefore, the aim of this systematic review was to give an overview of all population-based studies reporting on the prevalence and incidence rates of IR in childhood.

METHODS

PubMed, Embase, and Cochrane library were searched in order to find all available population-based studies describing the epidemiology of IR in pediatric populations. Prevalence rates together with methods and cut-off values used to determine IR were extracted and summarized with weight and sex specific prevalence rates of IR if available.

RESULTS

Eighteen population-based studies were identified, describing prevalence rates varying between 3.1 and 44%, partly explained by different definitions for IR. Overweight and obese children had higher prevalence rates than normal weight children. In seven out of thirteen studies reporting sex specific results, girls seemed to be more affected than boys.

CONCLUSION

Prevalence rates of IR reported in children vary widely which is partly due to the variety of definitions used. Overweight and obese children had higher prevalence and girls were more insulin resistant than boys. Consensus on the definition for IR in children is needed to allow for comparisons between different studies.

The clinical translation gap in child health exercise research: a call for disruptive innovation

In children, levels of play, physical activity, and fitness are key indicators of health and disease and closely tied to optimal growth and development. Cardiopulmonary exercise testing (CPET) provides clinicians with biomarkers of disease and effectiveness of therapy, and researchers with novel insights into fundamental biological mechanisms reflecting an integrated physiological response that is hidden when the child is at rest. Yet the growth of clinical trials utilizing CPET in pediatrics remains stunted despite the current emphasis on preventative medicine and the growing recognition that therapies used in children should be clinically tested in children. There exists a translational gap between basic discovery and clinical application in this essential component of child health. To address this gap, the NIH provided funding through the Clinical and Translational Science Award (CTSA) program to convene a panel of experts. This report summarizes our major findings and outlines next steps necessary to enhance child health exercise medicine translational research. We present specific plans to bolster data interoperability, improve child health CPET reference values, stimulate formal training in exercise medicine for child health care professionals, and outline innovative approaches through which exercise medicine can become more accessible and advance therapeutics across the broad spectrum of child health.

Balanced duo of anti-inflammatory SFRP5 and proinflammatory WNT5A in children

BACKGROUND

Secreted frizzled-related protein 5 (SFRP5) is an adipokine protecting against obesity-related insulin resistance and diabetes. SFRP5 binds to wingless type mouse mammary tumor virus (MMTV) integration site family member 5A (WNT5A) to improve insulin sensitivity. We performed the first study of SFRP5 and WNT5A simultaneously in children.

METHODS

Prepubertal children (n = 342) were assessed for circulating SFRP5 (all subjects) and circulating WNT5A (210 subjects), and associations were sought with metabolic markers. In conditioned media of adipose tissue explants from 12 additional children, SFRP5 and WNT5A were studied further.

RESULTS

The concentrations of SFRP5 and WNT5A correlated positively in serum and in conditioned media (all P < 0.001). Lower level of circulating SFRP5 (lowest quartile) was associated with higher BMI (15% increase, P < 0.0001) and lower level of high-molecular-weight adiponectin (26% decrease, P = 0.002). Circulating WNT5A related closely with insulin resistance assessed by the homeostasis model assessment for insulin resistance and hepatic markers (alanine transaminase and gamma glutamyl transpeptidase), particularly in children with lower circulating SFRP5 levels (all P < 0.004).

CONCLUSION

SFRP5 and WNT5A comprise a balanced duo that may regulate metabolic homeostasis in prepubertal children.

Testing the effectiveness of an abbreviated version of the Nutrition Detectives program

Introduction

Obese or overweight children have an increased risk for chronic diseases. Targeting diet and exercise in schools could help prevent childhood obesity. We have previously shown the effectiveness of a 90-minute nutrition program in improving elementary school students’ food-label literacy. The objective of this study was to investigate the effectiveness of a 45-minute version of the program.

Methods

We conducted a pre–post study in a public school district, with no control group. We provided teacher training and program materials. Participants were 5th-grade students in 5 schools who had parental consent and were willing to take part. We condensed the program to a 45-minute lesson with a presentation and hands-on activity. The lesson showed students why and how to make healthful food choices based on Nutrition Facts panels and ingredient lists. The district’s physical education teachers taught the lesson. The primary outcome measure was food-label literacy (ie, the ability to distinguish between more and less healthful foods using a validated test instrument with Nutrition Facts panels and ingredient lists).

Results

A total of 212 students completed pre–post measures. Following program delivery, we observed a significant gain of 16.2 percentage points in scores overall, ranging from 4.3 percentage points to 23.6 percentage points among schools. Results were similar to those achieved with the 90-minute program.

Discussion

The condensed nutrition program improved students’ food-label literacy while requiring a minimal allocation of time. Further studies in other school districts would be useful.

Body mass index and waist circumference: relationship to cardiometabolic risk factors in children--Busselton Health Study 2005-2007

AIM

This study aims to analyse the continuous relationship of each cardiometabolic risk factor with body mass index (BMI) and waist circumference percentiles in a population-based sample of children.

METHODS

A cross-sectional sample of 996 school children aged 6-16.9 years in Busselton, Western Australia, (2005-2007) had anthropometry and fasting blood tests for total cholesterol, high density lipoprotein, low density lipoprotein, triglycerides, glucose, insulin, high-sensitive C-reactive protein, liver function tests and adiponectin. Age- and menarche (for girls)-adjusted means of each risk factor were related to BMI and waist circumference centiles across the full normal-overweight-obese range.

RESULTS

The correlations between BMI and waist circumference (boys 0.91 and girls 0.91) and between BMI z-score and waist z-score (boys 0.80 and girls 0.82) were high. An increase in insulin across all centile groups (for BMI and waist circumference) was found in both sexes. An increase was found for diastolic blood pressure and systolic blood pressure z-score, high density lipoprotein, high-sensitive C-reactive protein, alanine transaminase and gamma-glutamyltransferase in only the centile groups >85% for BMI and waist circumference for both sexes. Mixed and sex-discordant results were found for triglycerides, adiponectin and glucose.

CONCLUSION

There are important differences in the relationships between increasing BMI/adiposity, and each comorbidity and these relationships can differ between boys and girls. This information has implications for screening and management of adiposity-related cardiometabolic risk factors in children and for public health initiatives to reduce future burden of cardiovascular disease.

ROCK1 in AgRP neurons regulates energy expenditure and locomotor activity in male mice

Normal leptin signaling is essential for the maintenance of body weight homeostasis. Proopiomelanocortin- and agouti-related peptide (AgRP)-producing neurons play critical roles in regulating energy metabolism. Our recent work demonstrates that deletion of Rho-kinase 1 (ROCK1) in the AgRP neurons of mice increased body weight and adiposity. Here, we report that selective loss of ROCK1 in AgRP neurons caused a significant decrease in energy expenditure and locomotor activity of mice. These effects were independent of any change in food intake. Furthermore, AgRP neuron-specific ROCK1-deficient mice displayed central leptin resistance, as evidenced by impaired Signal Transducer and Activator of Transcription 3 activation in response to leptin administration. Leptin's ability to hyperpolarize and decrease firing rate of AgRP neurons was also abolished in the absence of ROCK1. Moreover, diet-induced and genetic forms of obesity resulted in reduced ROCK1 activity in murine arcuate nucleus. Of note, high-fat diet also impaired leptin-stimulated ROCK1 activity in arcuate nucleus, suggesting that a defect in hypothalamic ROCK1 activity may contribute to the pathogenesis of central leptin resistance in obesity. Together, these data demonstrate that ROCK1 activation in hypothalamic AgRP neurons is required for the homeostatic regulation of energy expenditure and adiposity. These results further support previous work identifying ROCK1 as a key regulator of energy balance and suggest that targeting ROCK1 in the hypothalamus may lead to development of antiobesity therapeutics.

Measuring β-cell function relative to insulin sensitivity in youth: does the hyperglycemic clamp suffice?

OBJECTIVE

To compare β-cell function relative to insulin sensitivity, disposition index (DI), calculated from two clamps (2cDI, insulin sensitivity from the hyperinsulinemic-euglycemic clamp and first-phase insulin from the hyperglycemic clamp) with the DI calculated from the hyperglycemic clamp alone (hcDI).

RESEARCH DESIGN AND METHODS

Complete data from hyperglycemic and hyperinsulinemic-euglycemic clamps were available for 330 youth: 73 normal weight, 168 obese with normal glucose tolerance, 57 obese with impaired glucose tolerance, and 32 obese with type 2 diabetes. The correlation between hcDI and 2cDI and Bland-Altman analysis of agreement between the two were examined.

RESULTS

Insulin sensitivity and first-phase insulin from hcDI showed a hyperbolic relationship. The hcDI correlated significantly with 2cDI in the groups combined (r = 0.85, P < 0.001) and within each group separately (r ≥ 62, P < 0.001). Similar to 2cDI, hcDI showed a declining pattern of β-cell function across the glucose-tolerance groups. Overall, hcDI values were 27% greater than 2cDI, due to the hyperglycemic versus euglycemic conditions, reflected in a positive bias with Bland-Altman analysis.

CONCLUSIONS

β-Cell function relative to insulin sensitivity could be accurately evaluated from a single hyperglycemic clamp, obviating the need for two separate clamp experiments, when lessening participant burden and reducing research costs are important considerations.

Pediatric post-transplant metabolic syndrome: new clouds on the horizon

Liver transplantation (LT) is a standard treatment for children with end-stage liver disease, standing at more than 90% survival rate after one yr, and at over a 70% survival rate after five yr. The majority of transplanted children enjoy an excellent quality of life but complications can occur in the long term, and can develop subclinically in otherwise well children; there are various underestimated nutritional and metabolic aspects, including the so-called post-transplant metabolic syndrome (PTMS). During the post-transplant period, the use of immunosuppressants, corticosteroids, calcineurin inhibitors, and the presence of risk factors, including non-alcoholic fatty liver disease (NAFLD), and kidney and bone complications have been largely implicated in PTMS development. Strategies to reduce the progression of PMTS should include careful screening of patients for diabetes, dyslipidemia, and obesity, and to support weight reduction with a carefully constructed program, particularly based on diet modification and exercise. With early identification and appropriate and aggressive management, excellent long-term health outcomes and acceptable graft survival can be achieved.

What is metabolic syndrome, and why are children getting it?

Metabolic syndrome comprises a cluster of cardiovascular risk factors (hypertension, altered glucose metabolism, dyslipidemia, and abdominal obesity) that occur in obese children. However, metabolic syndrome can also occur in lean individuals, suggesting that obesity is a marker for the syndrome, not a cause. Metabolic syndrome is difficult to define, due to its nonuniform classification and reliance on hard cutoffs in the evaluation of disorders with non-Gaussian distributions. Defining the syndrome is even more difficult in children, owing to racial and pubertal differences and lack of cardiovascular events. Lipid partitioning among specific fat depots is associated with insulin resistance, which can lead to mitochondrial overload and dysfunctional subcellular energy use and drive the various elements of metabolic syndrome. Multiple environmental factors, in particular a typical Western diet, drive mitochondrial overload, while other changes in Western society, such as stress and sleep deprivation, increase insulin resistance and the propensity for food intake. These culminate in an adverse biochemical phenotype, including development of altered glucose metabolism and early atherogenesis during childhood and early adulthood.

Secreted frizzled-related protein 5 suppresses adipocyte mitochondrial metabolism through WNT inhibition

Preadipocytes secrete several WNT family proteins that act through autocrine/paracrine mechanisms to inhibit adipogenesis. The activity of WNT ligands is often decreased by secreted frizzled-related proteins (SFRPs). Sfrp5 is strongly induced during adipocyte differentiation and increases in adipocytes during obesity, presumably to counteract WNT signaling. We tested the hypothesis that obesity-induced Sfrp5 expression promotes the development of new adipocytes by inhibiting endogenous suppressors of adipogenesis. As predicted, mice that lack functional SFRP5 were resistant to diet-induced obesity. However, counter to our hypothesis, we found that adipose tissue of SFRP5-deficient mice had similar numbers of adipocytes, but a reduction in large adipocytes. Transplantation of adipose tissue from SFRP5-deficient mice into leptin receptor-deficient mice indicated that the effects of SFRP5 deficiency are tissue-autonomous. Mitochondrial gene expression was increased in adipose tissue and cultured adipocytes from SFRP5-deficient mice. In adipocytes, lack of SFRP5 stimulated oxidative capacity through increased mitochondrial activity, which was mediated in part by PGC1α and mitochondrial transcription factor A. WNT3a also increased oxygen consumption and the expression of mitochondrial genes. Thus, our findings support a model of adipogenesis in which SFRP5 inhibits WNT signaling to suppress oxidative metabolism and stimulate adipocyte growth during obesity.

Changes in lifestyle improve body composition, thyroid function, and structure in obese children

BACKGROUND

Alterations in thyroid function and structure have been reported in obesity. Function reverses to normal after weight loss, but nothing is known about structure.

AIM

To evaluate the effect of weight loss on thyroid function and structure in obese children.

SUBJECTS AND METHODS

The study was conducted in 72 overweight and obese children. Measurement of free T(3) (fT(3)), free T4 (fT(4)), TSH, antithyroid- antibodies and a thyroid ultrasound was performed at the beginning (phase 1) and after a period of 1.8±1.0 yr of lifestyle intervention (phase 2).

RESULTS

Height SD score (SDS), body mass index SDS, total fat mass did not change from phase 1 to phase 2. Percentage of fat free mass decreased significantly (p<0.05). Waist/height ratio decreased (0.6±0.1 vs 0.5±0.1; p<0.05) as well as waist/hip ratio (0.9±0.1 vs 0.8±0.1; p<0.05). In phase 1, TSH was 2.8±1.7 mU/l; in phase 2, it was 2.2±0.9 mU/l (p<0.05); 17.2% of children showed a TSH level above the normal range (3.6 mU/l) in phase 1, and 6.2% in phase 2 (p<0.05). fT(4) was 10.8±2.2 pg/ml in phase 1 and 10.7±1.9 pg/ml in phase 2. fT(3) was 4.4±1.3 pg/ml (phase 1) and 3.9±1.1 pg/ml (phase 2) (p<0.05). Thyroid volume was -0.5±0.8 SDS (phase 1) and -0.5±1 SDS (phase 2). A non-significant improvement in thyroid structure was observed.

CONCLUSIONS

In conclusion, healthier lifestyle improves body composition, thyroid function, and structure.

Obesity, inflammation and metabolic syndrome in Danish adolescents

AIM

To describe biomarkers of inflammation and markers related to the metabolic syndrome (MS) in healthy obese Danish adolescent and compare to a normal-weight group.

METHODS

Fifty-one obese and 30 normal-weight adolescents (12-15 years) were included. Anthropometry and blood pressure were measured, and blood was sampled.

RESULTS

Obese adolescents had significantly higher blood pressure, insulin, homeostasis model assessment of insulin resistance, C-peptide, total cholesterol, low-density lipoprotein cholesterol (LDL), triglyceride, C-reactive protein (CRP), interleukin-6 and tumour necrosis factor alpha and lower high-density lipoprotein cholesterol values, compared with normal-weight adolescents, whereas there were no differences between the groups for glucose, free fatty acids or faecal calprotectin. Within the obese group insulin, low-density lipoprotein cholesterol, and CRP were positively associated with body mass index (BMI) Z-scores. The MS was present in 14% of obese adolescents. CRP was positively associated with most anthropometric measures within the obese group, and in multiple linear regression analysis both BMI Z-score and the sum of skin folds explained a considerable part (R(2) = 0.421) of the variation in CRP.

CONCLUSION

Otherwise healthy Danish obese adolescents had marked low-grade inflammation, elevated biomarkers of the MS and high prevalence of the MS.

Body composition measured by dual-energy X-ray absorptiometry half-body scans in obese children

AIM

To perform a methods comparison of a left or right half-body scan versus whole-body scan for measuring body composition in a sample of obese children.

METHODS

A group of obese children (n = 58; ≥ 95th BMI percentile; 8-18 years) were required to undergo a dual-energy X-ray absorptiometry (DXA) body composition measurement as part of an ongoing cohort study; 34 fit within the imaging field of the DXA scanner and were eligible for inclusion in the present analysis. Percent fat, total mass, fat mass, lean mass and bone mineral content (BMC) were estimated from half-body scans and compared with the whole-body results. Assessment was completed using GE enCORE 11.40 software.

RESULTS

In comparing left- and right-side scans to whole-body scans, there was significant correlation for all body composition variables (p ≤ 0.005, R(2) = 0.996-1.0). Bland Altman analyses also showed high levels of agreement between half-body estimates and whole-body measurements.

CONCLUSION

This study supports using a half-body scan methodology for percent fat, total mass, fat mass, lean mass, and BMC as a valid alternative to full-body analysis in obese children and youth.

Family-based behavioural treatment of childhood obesity in a UK National Health Service setting: randomized controlled trial

Background

The best outcomes for treating childhood obesity have come from comprehensive family-based programmes. However there are questions over their generalisability.

Objective

To examine the acceptability and effectiveness of ‘family-based behavioural treatment’ (FBBT) for childhood obesity in an ethnically and socially diverse sample of families in a UK National Health Service (NHS) setting.

Methods

In this parallel group, randomised controlled trial, 72 obese children were randomised to FBBT or waiting list control. Primary outcomes were body mass index (BMI) and BMI standard deviation scores (SDS). Secondary outcomes were weight, weight SDS, height, height SDS, waist, waist SDS, fat mass index, fat free mass index, blood pressure, and psychosocial measures. Outcomes were assessed at baseline and post-treatment, with analyses on the 6 month data done on an intent-to-treat (ITT) basis. Follow-up anthropometric data were collected at twelve months for the treatment group.

Results

ITT analyses included all children with baseline data (n=60). There were significant BMI SDS changes (p<0.01) for the treatment and control groups of −0.11 (0.16) and −0.10 (1.6). The treatment group showed a significant reduction in systolic blood pressure (−0.24 (0.7), p<0.05) and improvements in quality of life and eating attitudes (p<0.05), with no significant changes for the control group. However the between-group treatment effects for BMI, body composition, blood pressure and psychosocial outcomes were not significant. There was no overall change in BMI or BMI SDS from 0-12 months for the treatment group. No adverse effects were reported.

Conclusions

Both treatment and control groups experienced significant reductions in level of overweight, but with no significant difference between them. There were no significant group differences for any of the secondary outcomes.

Adipokine ganglioside GM2 activator protein stimulates insulin secretion

Recently, we identified ganglioside GM2 activator protein (GM2AP) as a novel adipokine, and revealed that treatment of cultured cells with GM2AP impairs insulin signal transduction. The aim of this study was to examine the impact of GM2AP on glucose metabolism in vivo. Injection of recombinant GM2AP in mice significantly lowered blood glucose levels in glucose tolerance tests. Administration of GM2AP to mice for 10 days increased serum insulin levels, whereas the contents of glucose, leptin and FFA were significantly decreased. Stimulation of calcium influx and insulin secretion by GM2AP was observed in hamster insulinoma HIT-T15 cells. Blockage of GM2AP function by specific antibodies inhibited GM2AP-induced insulin secretion. These results provide novel insights into the physiological functions of GM2AP in obesity.

Management of metabolic syndrome in children and adolescents

Concomitantly with the increasing prevalence of childhood obesity, the prevalence of metabolic syndrome (MS) is rising among children and adolescents, leading to fears for future epidemics of type 2 diabetes mellitus and cardiovascular disease in the young. This makes the accurate identification and the appropriate treatment of children and adolescents with MS an important priority for health care systems. This review will focus on the management of each component of MS, including the nonalcoholic fatty liver disease (NAFLD), which is currently considered as the hepatic component of the syndrome. The most relevant target of treatment of MS in children and adolescents is the abdominal obesity. To this end, we will discuss the efficacy of dietary approaches, possibly coupled with regular physical activity, on eliciting visceral fat reduction. We will also highlight several aspects of the treatment of the high triglyceride/low high-density lipoprotein cholesterol phenotype, including the use of non-pharmacological measures, and indications for instituting drug therapies. Part of this review will address treatment of glucose abnormalities, including the benefits of lifestyle modification alone, and the potential adjunctive role of hypoglycemic drugs. The treatment of hypertension in children with MS also requires a multifaceted approach and the available data of this topic will be examined. The remainder of this review will address treatment to reverse NAFLD and prevent progression to end-stage disease.

The association of micronucleus frequency with obesity, diabetes and cardiovascular disease

Obesity and metabolic syndrome (MetS) are serious and growing health care problems worldwide, leading an increased risk for type 2 diabetes (T2D) and cardiovascular disease (CVD). Over the past decade, emerging evidence has shown that an increased chromosomal damage, as determined by the cytokinesis-block micronucleus (CBMN) assay, is correlated to the pathogenesis of metabolic and CVD. An increased micronuclei (MN) frequency has been demonstrated in peripheral blood lymphocytes of patients with polycystic ovary syndrome, a common condition in reproductive-aged women associated with impaired glucose tolerance, T2D mellitus and the MetS. High levels of MN have been detected to be significantly correlated with T2D as well as with the occurrence and the severity of coronary artery disease (CAD). Long-term follow-up studies have shown that an increased MN frequency is a predictive biomarker of cardiovascular mortality within a population of healthy subjects as well as of major adverse cardiovascular events in patients with known CAD. Overall, these findings support the hypothesis that CBMN assay may provide an useful tool for screening of the MetS and its progression to diabetes and CVD in adults as well in children. Large population-based cohorts are needed in order to compare the MN frequencies as well as to better define whether MN is a biomarker or a mediator of cardiometabolic diseases.

Impact of obesity on children undergoing liver transplantation

Controversies exist with respect to the mortality of patients undergoing liver transplantation at the extremes of the body mass index (BMI). For pediatric liver transplantation, weight is usually the only factor considered in survival analysis. A review of the United Network for Organ Sharing database (1987-2007) revealed 9701 pediatric patients (<18 years old) who underwent primary liver transplantation. Patients were stratified into 5 BMI categories established by the World Health Organization according to their Z score, which was based on age, gender, and BMI: -3, -2, 0, +2, and +3. The survival rates in these 5 categories were compared with Kaplan-Meier survival curves and log-rank testing. Patients with thinness (Z score = -2) and severe thinness (Z score = -3) had significantly (P < 0.0001) lower survival at 1 year (84.4%) versus the survival (88.7%) of the normal and overweight groups (Z score = 0 and Z score = + 2, respectively). For patients with obesity (Z score = +3), there was no significant difference in survival early after transplantation, but their mortality gradually increased in the later years after transplantation. By 12 years after liver transplantation, the obese group had significantly (P = 0.04) lower survival (72%) than the normal and overweight groups (77%). In conclusion, liver transplantation holds increased risk for obese pediatric patients. Thin pediatric patients experience early mortality after liver transplantation, and obese pediatric patients experience late mortality after liver transplantation. Transplant management can be modified to optimize the care of these patients.

A novel adipokine GM2AP impairs insulin signaling

In an attempt to discover novel adipokines, we performed proteomics analyses using culture medium from differentiated 3T3-L1 adipocytes, and first identified GM2AP. The levels of GM2AP mRNA and protein were augmented by adipogenesis in cultured adipocytes and expression in adipose tissue and serum of obese mice or human subjects was found to be significantly higher than in lean counterparts. Exposure of 3T3-L1 adipocytes to GM2AP protein accelerated dissociation of insulin receptor-beta (IRβ) from caveolin-1, and interrupted insulin signal transduction. Abrogation of GM2AP function by specific antibodies augmented glucose uptake. Furthermore, treatment of rat pheochromocytoma PC12 NS1 cells with GM2AP impaired NGF signal transduction. Taken together, these results provide novel insights into the physiological functions of GM2AP in obesity.