Relationship between glucose homeostasis and obesity in early life-a study of Italian children and adolescents

Continuous Glucose Monitoring-New Diagnostic Tool in Complex Pathophysiological Disorder of Glucose Metabolism in Children and Adolescents with Obesity

Obesity is one of the leading causes of chronic diseases, and its prevalence is still rising in children and adolescent populations. Chronic cardiovascular complications result in metabolic syndrome (MS) and type 2 diabetes mellitus. Key factors in the development of MS are insulin resistance and low-grade inflammation. The disorder of glucose and insulin metabolism has not been fully elucidated so far, and an oral glucose tolerance test (OGTT) has been the only tool used to look into the complex metabolism disorder in children and adolescents with obesity. Continuous glucose monitoring (CGM) has become commercially available for over two decades and is primarily used to manage type 1 diabetes mellitus in pediatric populations. This review aims to present the current knowledge about the use of CGM in children and adolescent populations with obesity. CGM systems have the potential to serve as valuable tools in everyday clinical practices, not only in the better diagnosis of chronic complications associated with obesity, but CGM can also assist in interventions to make better adjustments to nutritional and therapeutic approaches based on real-time glucose monitoring data. Despite these promising benefits, further research is needed to fully understand the role of CGM in metabolic disorders in pediatric populations with obesity, which will additionally strengthen the importance of CGM systems in everyday clinical practices.

Sex- and time-specific associations of obesity with glycaemic traits: A two-step multivariate Mendelian randomization study

AIM

To assess the sex- and time-specific causal effects of obesity-related anthropometric traits on glycaemic traits.

MATERIALS AND METHODS

We used univariate and multivariate Mendelian randomization to assess the causal associations of anthropometric traits (gestational variables, birth weight, childhood body mass index [BMI], BMI, waist-to-hip ratio [WHR], BMI-adjusted WHR [WHRadj BMI]) with fasting glucose and insulin in Europeans from the Early Growth Genetics Consortium (n ≤ 298 142), the UK Biobank, the Genetic Investigation of Anthropometric Traits Consortium (n ≤ 697 734; females: n ≤ 434 794; males: n ≤ 374 754) and the Meta-Analyses of Glucose and Insulin-related traits Consortium (n ≤ 151 188; females: n ≤ 73 089; males: n ≤ 67 506), adjusting for maternal genetic effects, smoking, alcohol consumption, and age at menarche.

RESULTS

We observed a null association for gestational variables, a negative association for birth weight, and positive associations for childhood BMI and adult traits (BMI, WHR, and WHRadj BMI). In female participants, increased birth weight causally decreased fasting insulin (betaIVW , -0.07, 95% confidence interval [CI] -0.11 to -0.03; p = 1.92 × 10-3 ), but not glucose levels, which was annulled by adjusting for age at menarche. In male participants, increased birth weight causally decreased fasting glucose (betainverse-variance-weighted (IVW) , -0.07, 95% CI -0.11 to -0.03; p = 3.22 × 10-4 ), but not insulin levels. In time-specific analyses, independent effects of birth weight were absent in female participants, and were more pronounced in male participants. Independent effects of childhood BMI were attenuated in both sexes; independent effects of adult traits differed by sex.

CONCLUSIONS

Our findings provide evidence for causal and independent effects of sex- and time-specific anthropometric traits on glycaemic variables, and highlight the importance of considering multiple obesity exposures at different time points in the life course.

High 1-h glucose in youths with obesity as marker of prediabetes and cardiovascular risk

PURPOSE

Testing 1-h glucose (1HG) concentration during oral glucose tolerance test is cost-effective to identify individuals at risk of incident type 2 diabetes. Aim of the study was to define 1HG cutoffs diagnostic of incident impaired glucose tolerance (IGT) in youths with obesity, and to evaluate prevalence and association of cutoffs identified in the cohort and from the literature (133 and 155 mg/dl) to cardiovascular disease (CVD) in a population of youths with obesity.

METHODS

This is a longitudinal study of 154 youths to identify 1HG cutoffs, and cross-sectional study of 2295 youths to estimate prevalence of high 1HG and association to CVD. Receiver-operating characteristic curves (ROC) were used to establish 1HG cutoffs, and univariate regression analyses to test association of 1HG to blood pressure, lipids and aminotransferases.

RESULTS

ROC analysis identified the 1HG cutoff of 159 mg/dl as having diagnostic accuracy of IGT with area under the ROC 0.82 (95% CI 0.66-0.98), sensitivity 0.86% and specificity 0.79%. In the cross-sectional population, prevalence of high 1HG was 36% and 15% for 133 and 155 mg/dl cutoffs, respectively, and 17% for the 159 mg/dl value. All the examined cutoffs were significantly associated with worse lipid profile, liver function test, reduced insulin sensitivity, secretion and disposition index.

CONCLUSION

High 1HG is marker of persistent IGT and increased risk of metabolic abnormalities in youths. The 155 mg/dl cutoff is a convenient estimate in young people but longitudinal studies with retinopathy and overt diabetes as end points are advised to verify the 1HG cutoff with the best diagnostic accuracy.

Magnesium Deficiency and Cardiometabolic Disease

Magnesium (Mg²⁺) has many physiological functions within the body. These include important roles in maintaining cardiovascular functioning, where it contributes to the regulation of cardiac excitation-contraction coupling, endothelial functioning and haemostasis. The haemostatic roles of Mg²⁺ impact upon both the protein and cellular arms of coagulation. In this review, we examine how Mg²⁺ homeostasis is maintained within the body and highlight the various molecular roles attributed to Mg²⁺ in the cardiovascular system. In addition, we describe how nutritional and/or disease-associated magnesium deficiency, seen in some metabolic conditions, has the potential to influence cardiac and vascular outcomes. Finally, we also examine the potential for magnesium supplements to be employed in the prevention and treatment of cardiovascular disorders and in the management of cardiometabolic health.

From Metabolic Syndrome to Type 2 Diabetes in Youth

In the frame of metabolic syndrome, type 2 diabetes emerges along a continuum of the risk from the clustering of all its components, namely visceral obesity, high blood pressure and lipids, and impaired glucose homeostasis. Insulin resistance is the hallmark common to all the components and, in theory, is a reversible condition. Nevertheless, the load that this condition can exert on the β-cell function at the pubertal transition is such as to determine its rapid and irreversible deterioration leading to plain diabetes. The aim of this review is to highlight, in the context of metabolic syndrome, age-specific risk factors that lead to type 2 diabetes onset in youth; resume age specific screening and diagnostic criteria; and anticipate potential for treatment. Visceral obesity and altered lipid metabolism are robust grounds for the development of the disease. Genetic differences in susceptibility to hampered β-cell function in the setting of obesity and insulin resistance largely explain why some adolescents with obesity do develop diabetes at a young age and some others do not. Lifestyle intervention with a healthy diet and physical activity remains the pillar of the type 2 diabetes treatment in youth. As to the pharmacological management, metformin and insulin have failed to rescue β-cell function and to ensure long-lasting glycemic control in youth. A new era might start with the approval for use in pediatric age of drugs largely prescribed in adults, such as dipeptidyl peptidase-4 and sodium-dependent glucose transport inhibitors, and of new weight-lowering drugs in the pipeline such as single and multiple agonists of the glucagon-like peptide 1 receptor. The latter drugs can have tremendous impact on the natural history of the disease. By treating diabetes, they will reduce the burden of all the metabolic abnormalities belonging to the syndrome while causing a tremendous weight loss hitherto never seen before.

Circulating Extracellular Vesicles Impair Mesenchymal Stromal Cell Differentiation Favoring Adipogenic Rather than Osteogenic Differentiation in Adolescents with Obesity

Excess body weight has been considered beneficial to bone health because of its anabolic effect on bone formation; however, this results in a poor quality bone structure. In this context, we evaluated the involvement of circulating extracellular vesicles in the impairment of the bone phenotype associated with obesity. Circulating extracellular vesicles were collected from the plasma of participants with normal weight, as well as overweight and obese participants, quantified by flow cytometry analysis and used to treat mesenchymal stromal cells and osteoblasts to assess their effect on cell differentiation and activity. Children with obesity had the highest amount of circulating extracellular vesicles compared to controls. The treatment of mesenchymal stromal cells with extracellular vesicles from obese participants led to an adipogenic differentiation in comparison to vesicles from controls. Mature osteoblasts treated with extracellular vesicles from obese participants showed a reduction in differentiation markers in comparison to controls. Children with obesity who regularly performed physical exercise had a lower circulating extracellular vesicle amount in comparison to those with a sedentary lifestyle. This pilot study demonstrates how the high amount of circulating extracellular vesicles in children with obesity affects the bone phenotype and that physical activity can partially rescue this phenotype.

Effects of PPARG and PPARGC1A gene polymorphisms on obesity markers

Pediatric obesity presents a multifactorial etiology, which involves genetic traits as well, including single nucleotide polymorphisms. The aim of the study is to investigate the contribution of PPARG gene polymorphisms (namely Pro12Ala rs1801282, His447His rs3856806, and Pro115Gln rs1800571) and PPARGC1A rs8192678 SNP on the anthropometric and metabolic parameters in a population of Romanian children. We conducted a cross-sectional study of 295 Caucasian children, divided according to the body mass index (BMI) z-score into the study (obese and overweight) group of 130 children and the control (normoponderal) group of 165 children. Anthropometric parameters were greater in the obese and overweight population as opposed to controls, with significant differences (p < 0.01) found for the weight (2.77 ± 1.54 SD vs. -0.04 ± 1.15 SD), body mass index (BMI) (2.28 ± 0.97 SD vs. -0.18 ± 1.19 SD), mid-upper arm circumference (MUAC) (4.59 ± 2.28 SD vs. 0.28 ± 3.45 SD), tricipital skin-fold (TSF) (3.31 ± 3.09 SD vs. 0.62 ± 7.28 SD) and waist-to-height ratio (WHtR) (0.61 ± 1.51 SD vs. -0.35 ± 1.35 SD) z-scores. Moreover, triglyceride values were higher in the study group (118.70 ± 71.99 SD vs. 77.09 ± 37.39 SD). No significant difference in the allele and genotype distribution of investigates gene polymorphisms was observed between the studied groups (p > 0.05). PPARG (rs1801282, rs3856806, and rs1800571) were not associated with demographic, anthropometric, and laboratory parameters. However, PPARGC1A rs8192678 CC genotype was associated with TSF z-score (p = 0.03), whereas total and LDL cholesterol levels were significantly higher among TT homozygotes (p < 0.01). Our data suggest that PPARG (rs1801282, rs3856806, and rs1800571) and PPARGC1A (rs8192678) gene polymorphisms were not associated with childhood and adolescence overweight and obesity. The present study identified a significant increase in fasting glucose levels, triglyceride, albumin, and ALT levels in children with excess weight, as well as expected important upward variation of anthropometric parameters (BMI, MUAC, TSF z-scores).

Circulating levels of PIN1 and glucose metabolism in young people with obesity

PURPOSE

Impaired activity of the peptidylprolyl cis/trans isomerase NIMA-interacting 1 (PIN1) isomerase might contribute to link disturbed glucose metabolism and risk of glucose related neurotoxicity, neurodegeneration and cognitive decline. The isomerase modulates also pathways of peripheral insulin sensitivity and secretion. We aimed at investigating the levels of circulating PIN1 in adolescents with obesity and any association with their glucose metabolism.

METHODS

We enrolled 145 adolescents (age 12-17.8 years); 67 lean controls (46.2%) and 78 (53.8%) with overweight or obesity (males n = 62, 46%). We estimated glucose and insulin in fasting condition and after a standard oral glucose tolerance test; fasting serum levels of PIN1, amyloid β-protein 42 (Aβ42), presenilin 1 (PSEN1), glucagon-like peptide 1 (GLP1) and Non Esterified Fatty Acids (NEFA). We calculated the homeostasis model assessment of insulin resistance (HOMA-IR), the β cell function (HOMA-β) and the Adipo-IR.

RESULTS

There was no difference in PIN1 serum levels between normal weight individuals and patients with obesity. However, there was an inverse correlation between serum fasting PIN1 and glucose (r - 0.183 and p = 0.027). We confirmed levels of Aβ42 and PSEN1 were higher in teens with obesity than in lean controls and their correlation with the body mass index (Aβ42: r = 0.302, p = 0.0001, PSEN1 r = 0.231, p = 0.005) and the HOMA-IR (Aβ42: r = 0.219, p = 0.009, r = 0.170, p < 0.042).

CONCLUSIONS

There was no significant rise of circulating PIN1 levels in young individuals with obesity. Increased levels reported in the literature in adult patients are likely to occur late in the natural history of the disease with the onset of an overt impairment of glucose homeostasis.

Insulin resistance in children

PURPOSE OF REVIEW

Insulin resistance (IR) is a clinical condition due to the decline in the efficiency of insulin promoting glucose uptake and utilization. The aim of this review is to provide an overview of the current knowledge on IR in children, focusing on its physiopathology, the most appropriate methods of measurement of IR, the assessment of risk factors, the effects of IR in children, and finally giving indications on screening and treatment.

RECENT FINDINGS

IR has evolved more and more to be a global public health problem associated with several chronic metabolic diseases.

SUMMARY

Detecting a correct measurement method and specific risk predictors, in order to reduce the incidence of IR, represents a challenging goal.

Prevalence of prediabetes in children and adolescents by class of obesity

BACKGROUND

To evaluate prevalence of prediabetes (impaired fasting glucose, IFG; impaired glucose tolerance, IGT; and high glycated haemoglobin, h-HbA1c) in children and adolescents in relation to class of age and obesity; to appraise association with estimates of insulin metabolism, cardiovascular risk factors and alanine aminotransferase (ALT) levels.

METHODS

Study of marginal prevalence (i.e., as function of sex, age and obesity class) of isolated and combined IFG, IGT and h-HbA1c in children (age 4-9.9 years) and adolescents (age 10-17.9 years) and association to blood pressure (BP), total, HDL and non-HDL cholesterol, triglycerides, ALT and insulin sensitivity/secretion indexes.

RESULTS

Data of 3110 participants (51% males, 33% children; 33% overweight, 39% obesity class I, 20.5% class II, 7.5% class III) were available. Unadjusted prevalence of prediabetes was 13.9% in children (2.1% IFG, 6.7% IGT, 3.9% h-HbA1c, IFG-IGT 0.06%) and 24.6% in adolescents (3.4% IFG, 9.4% IGT, 5.5% h-HbA1c, IFG-IGT 0.09%). Combined h-HBA1c was found in very few adolescents. Prevalence of prediabetes increased significantly by class of obesity up to 20.5% in children and 31.6% in adolescents. Phenotypes of prediabetes were differently but significantly associated with increased systolic and diastolic BP (by 2-7.3 and ~8 mmHg, respectively), triglycerides (by 23-66 mg/dl), and ALT levels (by 10-22 UI/L) depending on the prediabetes phenotype.

CONCLUSION AND RELEVANCE

It is worth screening prediabetes in children aged <10 years old with obesity classes II and III and in adolescents. In those with prediabetes, monitoring of blood pressure, triglycerides and ALT levels must be encouraged.

Genetic Variants Relate to Fasting Plasma Glucose, 2-Hour Postprandial Glucose, Glycosylated Hemoglobin, and BMI in Prediabetes

Diabetes mellitus (DM) is a chronic disease that seriously threatens human health. Prediabetes is a stage in the progression of DM. The level of clinical indicators including fasting plasma glucose (FPG), 2-h postprandial glucose (2hPG), and glycosylated hemoglobin (HbA1C) are the diagnostic markers of diabetes. In this genome-wide association study (GWAS), we aimed to investigate the association of genetic variants with these phenotypes in Hainan prediabetes. In this study, we recruited 451 prediabetes patients from the residents aged ≥18 years who participated in the National Diabetes Prevalence Survey of the Chinese Medical Association in 2017. The GWAS of FPG, 2hPG, HbA1C, and body mass index (BMI) in prediabetes was analyzed with a linear model using an additive genetic model with adjustment for age and sex. We identified that rs13052524 in MRPS6 and rs62212118 in SLC5A3 were associated with 2hPG in Hainan prediabetes (p = 4.35 × 10^-6, p = 4.05 × 10^-6, respectively). Another six variants in the four genes (LINC01648, MATN1, CRAT37, and SLCO3A1) were related to HbA1C. Moreover, rs11142842, rs1891298, rs1891299, and rs11142843 in TRPM3/TMEM2 and rs78432036 in MLYCD/OSGIN1 were correlated to BMI (all p < 5 × 10^-6). This study is the first to determine the genome-wide association of FPG, 2hPG, and HbA1C, which emphasizes the importance of in-depth understanding of the phenotypes of high-value susceptibility gene markers in the diagnosis of prediabetes.