Glucose dysregulation in obese children: predictive, risk, and potential protective factors

Difference in Insulin Resistance Assessment between European Union and Non-European Union Obesity Treatment Centers (ESPE Obesity Working Group Insulin Resistance Project)

INTRODUCTION

The obesity epidemic has become one of the most important public health issues of modern times. Impaired insulin sensitivity seems to be the cornerstone of multiple obesity related comorbidities. However, there is no accepted definition of impaired insulin sensitivity.

OBJECTIVE

We hypothesize that assessment of insulin resistance differs between centers.

METHODS

The ESPE Obesity Working Group (ESPE ObWG) Scientific Committee developed a questionnaire with a focus on the routine practices of assessment of hyperinsulinemia and insulin resistance, which was distributed through Google Docs platform to the clinicians and researchers from the current ESPE ObWG database (n = 73). Sixty-one complete responses (84% response rate) from clinicians and researchers were analyzed: 32 from European Union (EU) centers (representatives of 14 countries) and 29 from Non-EU centers (representatives from 10 countries). Standard statistics were used for the data analysis.

RESULTS

The majority of respondents considered insulin resistance (IR) as a clinical tool (85.2%) rather than a research instrument. For the purpose of IR assessment EU specialists prefer analysis of the oral glucose tolerance test (OGTT) results, whereas non-EU ones mainly use Homeostatic Model Assessment of Insulin Resistance (HOMA-IR; p = 0.032). There was no exact cutoff for the HOMA-IR in either EU or non-EU centers. A variety of OGTT time points and substances measured per local protocol were reported. Clinicians normally analyzed blood glucose (88.52% of centers) and insulin (67.21%, mainly in EU centers, p = 0.0051). Furthermore, most participants (70.5%) considered OGTT insulin levels as a more sensitive parameter of IR than glucose. Meanwhile, approximately two-thirds (63.9%) of the centers did not use any cutoffs for the insulin response to the glucose load.

CONCLUSIONS

Since there is no standard for the IR evaluation and uniform accepted indication of performing, an OGTT the assessment of insulin sensitivity varies between EU and non-EU centers. A widely accepted standardized protocol is needed to allow comparison between centers.

The Potential Role of Exosomes in Child and Adolescent Obesity

Child and adolescent obesity constitute one of the greatest contemporary public health menaces. The enduring disproportion between calorie intake and energy consumption, determined by a complex interaction of genetic, epigenetic, and environmental factors, finally leads to the development of overweight and obesity. Child and adolescent overweight/obesity promotes smoldering systemic inflammation (“para-inflammation”) and increases the likelihood of later metabolic and cardiovascular complications, including metabolic syndrome and its components, which progressively deteriorate during adulthood. Exosomes are endosome-derived extracellular vesicles that are secreted by a variety of cells, are naturally taken-up by target cells, and may be involved in many physiological and pathological processes. Over the last decade, intensive research has been conducted regarding the special role of exosomes and the non-coding (nc) RNAs they contain (primarily micro (mi) RNAs, long (l) non-coding RNAs, messenger (m) RNAs and other molecules) in inter-cellular communications. Through their action as communication mediators, exosomes may contribute to the pathogenesis of obesity and associated disorders. There is increasing evidence that exosomal miRNAs and lncRNAs are involved in pivotal processes of adipocyte biology and that, possibly, play important roles in gene regulation linked to human obesity. This review aims to improve our understanding of the roles of exosomes and their cargo in the development of obesity and related metabolic and inflammatory disorders. We examined their potential roles in adipose tissue physiology and reviewed the scarce data regarding the altered patterns of circulating miRNAs and lncRNAs observed in obese children and adolescents, compared them to the equivalent, more abundant existing findings of adult studies, and speculated on their proposed mechanisms of action. Exosomal miRNAs and lncRNAs could be applied as cardiometabolic risk biomarkers, useful in the early diagnosis and prevention of obesity. Furthermore, the targeting of crucial circulating exosomal cargo to tissues involved in the pathogenesis and maintenance of obesity could provide a novel therapeutic approach to this devastating and management-resistant pandemic.

The prognosis for glycemic status among children and youth with obesity 2 years after entering a weight management program

BACKGROUND

To address gaps in knowledge of the longitudinal trajectory of dysglycemia in children with obesity, this study aimed to: (1) describe the changes in glycemic status over 2 years; (2) establish a predictive model for development of prediabetes among children with euglycemia; and (3) evaluate the influence of change in body mass index (BMI) z-score on glycemic status.

METHODS

Children aged 5 to 17 years entered this prospective, longitudinal study at the time of entry to a weight management program. Measures included a 75-g oral glucose tolerance test (OGTT), fasting blood glucose, hemoglobin A1c (HbA1c), lipid profile, liver enzymes and anthropometric measures at baseline, 1 and 2 years. Cox proportional hazard was used to build a predictive model for prediabetes.

RESULTS

The cohort included 270 children, mean age: 11.6 ± 2.7 years and BMI z-score: 3.1. The baseline prevalence of prediabetes, based upon elevated 2-hour glucose in OGTT or HbA1c, was 100/270 (37.0%). Among children with prediabetes at baseline, 53 (53.0%) continued to have prediabetes over the following 2 years, 15 (15.0%) were euglycemic at 1 year and had prediabetes at 2 years, 20 (20.0%) became euglycemic and remained so. Change in BMI z-score predicted dysglycemic status at 2 years. Among those euglycemic at baseline, the incidence of prediabetes was 14 (8.2%) after 1 year, 20 (12.8%) at 2 years. Predictors of incident prediabetes were baseline BMI z-score; hazard ratio (HR): 1.72, 95th confidence interval (CI: 1.08, 2.74) and baseline HbA1c HR: 1.26, 95th CI (1.02-1.56) when controlling for age, family history of diabetes and sex.

CONCLUSION

Prediabetes presents significant morbidity in children with obesity. Family-based lifestyle interventions might delay prediabetes progression.

Involvement of stanniocalcins in the deregulation of glycaemia in obese mice and type 2 diabetic patients

Stanniocalcins are expressed in the pancreas tissue, and it was suggested a direct correlation between circulating insulin and STC2 concentrations in human. Here, we show a significant correlation between STC1 and both glycaemia and glycosylated haemoglobin among DM2 patients, while DM2 patients who present the greatest glycosylated haemoglobin values exhibited the lowest STC2 expression. However, treatment of patients with antiglycaemic drugs does not significantly modify the expression of both STCs. On the other hand, STC2-/- mice that exhibited neonatal and adult overweight further presented deregulated glycaemia when they were feed with a hypercaloric diet (breeding pellet, BP). This alteration is more evident at the early stages of the animal life. Deregulated glycaemia in these mice was confirmed using glucose oral test. In addition, STC2-/- mice present enhanced pancreas size; thus, the histological analysis reveals that WT mice respond to BP diet by increasing the size of the pancreatic islets through inducing cell division, and STC2-/- mice lack this compensatory mechanism. Contrary, BP fed STC2-/- mice show enhanced number of islets but of similar size than those fed with regular pellet. Histopathological analysis demonstrates tissue structure disruption and erythrocytes infiltrations in STC2-/- mice, possibly due to the stress evoked by the BP diet. Finally, enhanced glucagon immunostaining was observed in the islet of STC2-/- mice, and the glucagon ELISA assay confirmed the increase in the circulating glucagon. Summarizing, we present evidence of the role of STCs, mainly STC2, as a possible early marker during development of diabetes mellitus.

Does visceral adiposity index signify early metabolic risk in children and adolescents?: association with insulin resistance, adipokines, and subclinical inflammation

BACKGROUND

Visceral adiposity index (VAI) is a novel gender-specific index based on waist circumference (WC), BMI, and lipid parameters. Although VAI does not actually estimate visceral adiposity, it accurately reflects visceral fat function and insulin resistance. This index has not been studied in children thus far. This study aims to fill this gap.

METHODS

In a cohort of Saudi children and adolescents, anthropometric measurements and metabolic/hormonal profile were obtained.

RESULTS

A total of 543 subjects, 292 of whom were boys, were included (mean age: 11.9 ± 3.3 y; BMI: 19.8 ± 5.6 kg/m(2)). In all subjects, VAI was inferior to BMI and WC regarding its correlations with adiponectin, leptin, insulin resistance (homeostasis model of assessment-insulin resistance (HOMA-IR)), C-reactive protein (CRP) level, and systolic blood pressure, but it exhibited a stronger association with glucose in boys (r = 0.23; P < 0.01). In stepwise multivariate analyses, only BMI was consistent as an independent predictor of adiponectin, leptin, HOMA-IR, and CRP. VAI was the only index independently associated with glucose.

CONCLUSION

Although VAI is related to glucose in children, it seems to be inferior to BMI in terms of association with insulin resistance, adipokines, and subclinical inflammation. Until specific studies can be performed in children, VAI should be extrapolated with caution in this age range.

Integrating risks for type 2 diabetes across childhood: a life course perspective

Type 2 diabetes (T2DM) emerged among children, due in large measure to a strong physiological link between increased weight states and T2DM. In this article, cumulative risk factors for T2DM across childhood and its underlying mechanisms are reviewed. The points of intervention for T2DM should occur throughout childhood. The use of Halfon and Hochstein's framework enables practitioners and researchers in the nursing field to better understand a child's individual risk for T2DM. Only with this long view will prevention and interventions be successful in stemming the tide of the "twin epidemic" threatening children worldwide.

Vitamin D status and glucose homeostasis in obese children and adolescents living in the tropics

BACKGROUND

Pediatric obesity continues to rise and has become a major health problem worldwide. Vitamin D deficiency has been increasing among obese non-Asian children and is associated with abnormal glucose homeostasis in obese adults. However, data on the vitamin D status and its association with glucose homeostasis in obese children residing in tropical Asian countries are unavailable.

OBJECTIVE

To assess vitamin D status and glucose homeostasis in obese Thai children.

PATIENTS AND METHODS

A total of 150 obese, and 29 healthy non-obese children and adolescents were enrolled. Weight, height, body mass index (BMI) and waist circumference were obtained. All obese children underwent an oral glucose tolerance test with glucose and insulin measurements. Plasma 25-hydroxyvitamin D (25-OHD) and calciotropic blood chemistries were measured in all participants. Insulin sensitivity indices were calculated from the measured glucose and insulin levels.

RESULTS

Approximately 25% of the obese children and adolescents had impaired glucose tolerance, impaired fasting plasma glucose (FPG) and diabetes. Seventeen out of 150 (11.3%) obese children and 3 out of 29 (10.3%) non-obese children had vitamin D deficiency, which was defined as a 25-OHD level of <50 nmol l(-1). Glucose tolerance and insulin sensitivity indices were comparable between obese children with sufficient vitamin D and those with vitamin D deficiency. There were no relationships among serum 25-OHD; weight, height, and BMI standard deviation scores; insulin sensitivity indices; FPG and insulin; and 2-h plasma glucose and insulin levels.

CONCLUSION

Vitamin D deficiency is not as prevalent in obese Thai children as in obese non-Asian children from high-latitude countries. Adiposity per se is unlikely to be a determinant of vitamin D status in these obese individuals. There was no association between vitamin D deficiency and abnormal glucose homeostasis.