Association of Apelin Levels in Overweight-obese Children with Pubertal Development, but Not with Insulin Sensitivity: 6.5 Years Follow up Evaluation.

BACKGROUND: Obesity in youth is associated with increased risk of metabolic disorders. Adipose tissue hormones are involved in body-weight regulation. Among these, apelin is recognized as an insulin-sensitizer adipokine. Data on apelin levels in obese children and its relation to insulin-sensitivity are limited. OBJECTIVE: We aimed to evaluate apelin levels in relation to obesity and insulin sensitivity in a large cohort of overweight/obese children and adolescents. Furthermore, these youths were reevaluated after a median 6.5 years of follow-up, thus allowing assessing changes in apelin levels in relation to increasing age and weight changes. METHODS: Clinical data in 909 children and adolescents were collected between 2007 and 2010. Two hundred and one were reexamined at a median 6.5 years of follow-up. All subjects at baseline and at follow-up underwent an OGTT. Apelin levels were measured on sera by ELISA method. RESULTS: At baseline, lower apelin levels were associated with increasing age and puberty (Tanner ≥II 0.67 ± 0.96 ng/mL vs. Tanner I 0.89 ± 1.13 ng/mL, p < .002), but not with body-weight. At follow-up, apelin levels in the 201 subjects reexamined were significantly lower than at baseline (0.45 ± 0.77 ng/mL at follow-up, 0.68 ± 0.95 ng/mL baseline, p < .001), confirming the effects of age and puberty. Body-weight did not affect apelin levels. Multiple regression analysis confirmed that sex and puberty were associated with lower apelin levels, independently from age and insulin-sensitivity. CONCLUSIONS: Apelin levels decrease significantly with pubertal development, whilst body-weight in children and adolescents did not determine changes in apelin. Reduced levels of apelin in children and adolescents may therefore represent a necessary response to maintain the "physiological" insulin resistance of puberty. Abbreviations: ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; G: glucose; BMI: Body mass index; DBP: Diastolic blood pressure; ELISA: enzyme-linked immunosorbent assay; HDL-C: High-density lipoprotein-cholesterol; HOMA-B: Homeostatic model assessment for beta-cell function; HOMA-IR: Homeostatic model assessment of insulin-resistance; INS: Insulin; ISI: insulin-sensitivity index; LDL-C: Low-density lipoprotein cholesterol; NW: normal weight; OB: obese; OGTT: oral glucose tolerance test; OW: overweight; SBP: Systolic blood pressure; TC: Total cholesterol; TGs: Triglycerides.

Testing for type 1 diabetes autoantibodies in gestational diabetes mellitus (GDM): is it clinically useful?

Gestational Diabetes Mellitus (GDM) is the most common metabolic disorder in pregnancy, and it is associated with increased risk of morbidity in maternal-fetal outcomes. GDM is also associated with a higher risk to develop diabetes in the future. Diabetes-related autoantibodies (AABs) have been detected in a small percentage (usually less than 10%) of women with gestational diabetes. The prevalence in gestational diabetes of these autoimmune markers of type 1 diabetes (T1D) has been assessed in many studies, together with the risk of progression of AABs-positive GDM towards impaired glucose regulation (IFG or IGT) and overt diabetes after pregancy. The question whether it is necessary to test for T1D autoantibodies in all pregnancies with GDM is still debated. Here we examine the epidemiology of T1D autoantibodies in GDM, their clinical relevance in term of future risk of diabetes or impaired glucose regulation and in term of maternal-fetal outcomes, and discuss when it may be the most appropriate time to search for T1D autoantibodies in women with gestational diabetes.

The Arg282Ser missense mutation in APOA5 gene determines a reduction of triglyceride and LDL-cholesterol in children, together with low serum levels of apolipoprotein A-V.

BACKGROUND: Apolipoprotein A-V (ApoA-V) is a recognized regulator of plasma triglycerides (TGs), and previous studies have shown associations between variants in APOA5 (apolipoprotein-A5) gene and high TG levels. Recently, a new association between the Arg282Ser missense mutation (rs778114184 G > T) in APOA5 gene and decreased triglyceride levels has been shown in an adult population from Sardinia. In this study we add further insight into the role of APOA5 by exploring whether this association begins early in life in children, or becomes manifest only in adulthood. We performed the genetic association analysis of APOA5 in a cohort of 925 overweight and obese children and adolescents from Sardinia, Italy, to see if the genetic burden is already at play before modifying risk factors are interacting. RESULTS: We identified 24 heterozygous subjects for the Arg282Ser variant and no homozygous subject. Here we show that the Arg282Ser mutation in APOA5 gene is associated with a significant reduction of TG (-15.5 mg/dl), total (-18.1 mg/dl) and LDL-cholesterol (-14.8 mg/dl) levels in overweight/obese children and adolescents, indicating that indeed this association appears early in life. Also, we observed a significant reduction in serum apoA-V levels in heterozygous children. CONCLUSIONS: Our data clearly show that the Arg282Ser mutation in APOA5 gene determines a reduction of TG, total and LDL-cholesterol and apolipoprotein A-V levels in overweight/obese children and adolescents, demonstrating that this mutation has the power to affect lipid levels already since childhood.

The vitamin D receptor functional variant rs2228570 (C>T) does not associate with type 2 diabetes mellitus.

AIM: Vitamin D acts through the binding to the vitamin D receptor (VDR). Several polymorphisms in VDR gene have been studied. Among these, the rs2228570 C>T (FokI) variant has been demonstrated to be functional, leading to a protein with a different size and activity. So far, genetic studies on the association between VDR gene rs2228570 single nucleotide polymorphism (SNP) and type 2 diabetes mellitus (T2DM) showed contradictory results. Thus, we performed an association study in a large cohort of adult Italian subjects with T2DM and in nondiabetic controls. MATERIALS AND METHODS: For this study, 1713 subjects, 883 T2DM patients and 830 controls, were genotyped for the polymorphism. All participants without a diagnosis of diabetes underwent oral glucose tolerance test (OGTT), with measurement of glucose and insulin levels. Indices of insulin resistance (Homeostatic model assessment of insulin resistance, insulin sensitivity index), secretion (homeostatic model assessment for beta-cell, corrected insulin response at 30 minutes) and disposition index were calculated. RESULTS: Genotype distributions and allele frequencies did not show difference between T2DM subjects and controls. We did not find significant differences among the three genotypes regarding gender, age, BMI, waist, hip, waist-to-hip ratio, and blood pressure. There were also no significant differences in lipid parameters, aspartate aminotransferase, and alanine aminotransferase levels. We tested for association with OGTT-derived data and surrogate indices of insulin resistance and secretion. We did not find significant differences among the genotypes in any of above-mentioned parameters. Furthermore, vitamin D levels were measured in a subgroup of subjects. We did not find significant differences among the genotypes. CONCLUSIONS: Our study does not provide evidence for the association of the rs2228570 polymorphism with T2DM in a Caucasian population.

Effects of Metformin and Exercise Training, Alone or in Combination, on Cardiac Function in Individuals with Insulin Resistance.

INTRODUCTION: In patients affected by insulin resistance (IR), metformin (MET) therapy has been shown to exert its positive effects by improving glucose tolerance and preventing the evolution to diabetes. Recently, it was shown that the addition of metformin to physical training did not improve sensitivity to insulin or peak oxygen consumption (peak VO2). The purpose of this study was to establish the effect of metformin and exercise, separately or in combination, on systolic left ventricular (LV) function in individuals with IR. METHODS: Seventy-five patients with IR were enrolled and subsequently assigned to MET, combination MET and exercise, or exercise alone. The LV systolic and diastolic functions were evaluated with standard echocardiography tissue Doppler imaging (TDI) and speckle tracking echocardiography at baseline and after 12 weeks of treatment. RESULTS: MET, administered alone or in association with exercise, improved longitudinal LV function, as evidenced by an increase in systolic (S) wave on TDI, alongside increases in longitudinal global strain and strain rate in comparison to the group undergoing physical training alone. The traditional echocardiographic parameters showed no statistically significant differences among the three groups before or after the different cycles of therapy. CONCLUSIONS: Treatment with MET, either with or without exercise, but not exercise alone, produced a significant increase in global longitudinal LV systolic function at rest. These findings validate the observation that the use of MET alone or in association with exercise has a crucial role to counteract the negative effects of IR on cardiovascular function.

Search for Genetic Variant in the Apelin Gene by Resequencing and Association Study in European Subjects.

AIMS: Apelin is a peptide produced and secreted by white adipose tissue. It is synthesized as preproapelin, a protein containing 77 aminoacids which is then cleaved to shorter active fragments. As an adipokine, apelin plays a role in the regulation of many biological functions, including body energy homeostasis and glucose metabolism, water balance, and immunity. We have recently demonstrated that subjects with type 2 diabetes (T2D) have significantly higher serum apelin levels compared with controls, and that these levels associate with fasting glucose, basal disposition index, age, and diagnosis of T2D. The first aim of this study was to search for sequence variants in the apelin gene (APLN), located on chromosome Xq25-q26.1 that may associate with serum levels of apelin. The second aim was to analyze the possible association between diabetes and diabetes-related traits and APLN variants. METHODS: We designed a two-step genetic association study. Step one consisted of an initial screen of 100 individuals selected from the extremes of the apelin distribution levels wherein we sequenced the APLN gene to identify common variants. In step two, the rs181301686 with a minor allele frequency >0.2 was genotyped in 917 individuals to explore its association with T2D and diabetes-related traits. RESULTS: Five sequence variations were found across the APLN gene. To test for association with apelin levels, the rs181301686 and rs2281069 single-nucleotide polymorphisms were genotyped in 256 subjects for whom serum apelin levels were available. No significant differences were observed in apelin levels between genotypes. Association analysis in 917 individuals did not show significant differences between APLN genotypes and diabetes and diabetes-related traits. CONCLUSIONS: Resequencing of the apelin gene in subjects stratified by low or high apelin levels identified five APLN variants in an European population. No association was found between the most frequent variant, diabetes, and metabolic parameters.

The perilipin 2 (PLIN2) gene Ser251Pro missense mutation is associated with reduced insulin secretion and increased insulin sensitivity in Italian obese subjects.

BACKGROUND: Perilipin 2 (PLIN2), a member of the family of perilipin lipid droplets coating proteins, is very widely expressed. The Ser251Pro (rs35568725) missense mutation in exon 6 of PLIN2 gene was previously associated with increased lipid accumulation, decreased lipolysis and increased number of small lipid droplets per cell. Furthermore, the Pro251 mutation was associated with decreased plasma triglyceride and very low density lipoprotein concentrations in population studies. The aim of this study was to evaluate the effect of the Ser251Pro mutation of PLIN2 gene in a cohort with a higher predisposition to obesity-associated metabolic alterations, such as insulin resistance, decreased insulin-secretion, hyperglycaemia, and dyslipidaemia. METHODS: A large cohort (N = 1692) of Italian obese subjects (mean body mass index = 41 kg/m(2) ) was genotyped for the Ser251Pro mutation. All participants underwent oral glucose tolerance tests (OGTT), with measurement of glucose and insulin levels. Indices of insulin resistance and of insulin secretion were also calculated. Clinical and biochemical parameters were collected for all participants. RESULTS: We observed that insulin concentration was significantly reduced at 120 min after the administration of glucose in Pro251 allele carriers, whereas glucose levels were similar in Pro251 allele carriers and non-carriers throughout the OGTT. Furthermore, the CIR120 index of insulin secretion was significantly lower (P < 0.035) and the ISI index of insulin-sensitivity was significantly higher (P < 0.031) in carriers of the Pro251 allele. When we analysed men and women separately to test for gender-specific associations, we observed that in women insulin levels were significantly lower in Pro251 allele carriers compared with wild-type subjects throughout the whole OGTT. In men, we confirmed a significant reduction in insulin concentration only at 120 min after the OGTT. No significant differences between genotype groups regarding triglyceride levels and anyother clinical and metabolic parameters were observed. CONCLUSION: We observed a strong significant association between the PLIN2 Pro251 mutation and lower insulin secretion associated with an increased insulin sensitivity. Copyright © 2015 John Wiley & Sons, Ltd.

VGF Peptide Profiles in Type 2 Diabetic Patients' Plasma and in Obese Mice.

To address the possible involvement of VGF peptides in obesity and diabetes, we studied type 2 diabetes (T2D) and obese patients, and high-fat diet induced obese mice. Two VGF peptides (NAPP-19 and QQET-30) were identified in human plasma by HPLC-ESI-MS. The VGF C-terminus, the above two cleaved peptides, and the TLQP-21 related peptide/s were studied using ELISA and immunohistochemistry. In euglycemic patients, plasma NAPPE and TLQP like peptides were significantly reduced with obesity (74±10 vs. 167±28, and 92±10 vs. 191±19 pmol/ml, mean+SEM, n = 10 and 6, obese vs. normal BMI, respectively, p<0.03). Upon a standard glucose load, a distinct response was shown for VGF C-terminus, TLQP and QQET-like (ERVW immunoreactive) peptides in euglycemic normal BMI patients, but was virtually abolished in euglycemic obese, and in T2D patients independently of BMI. High-fat diet induced obese mice showed reduced plasma VGF C-terminus, NAPPE and QQET-like (ERVW) peptide/s (3±0.2 vs. 4.6±0.3, 22±3.5 vs. 34±1.3, and 48±7 vs. 100±7 pmol/ml, mean+SEM, n = 8/group, obese vs. slim, respectively, p<0.03), with a loss of the response to glucose for all VGF peptides studied. In immunohistochemistry, TLQP and/or VGF C-terminus antibodies labelled VGF containing perikarya in mouse celiac ganglia, pancreatic islet cells and thin beaded nerve fibres in brown adipose tissues, with fewer in white adipose tissue. Upon the glucose load, tyrosine hydroxylase and VGF C-terminus immunoreactive axons became apparent in pancreatic islets of slim animals, but not in obese animals. Alltogether, a significant loss of VGF peptide immunoreactivity and/or their response to glucose was demonstrated in obese patients, with or without T2D, in parallel with a similar loss in high-fat diet induced obese mice. An involvement of VGF in metabolic regulations, including those of brown and/or white adipose tissues is underlined, and may point out specific VGF peptides as potential targets for diagnosis and/or treatment.

Glycated hemoglobin for the diagnosis of diabetes and prediabetes: Diagnostic impact on obese and lean subjects, and phenotypic characterization.

AIMS/INTRODUCTION: Measurement of glycated hemoglobin (HbA1c) has been recommended for the diagnosis of diabetes and prediabetes. However, epidemiological studies have shown significant discordance between HbA1c and glucose-based tests. Of the factors that could influence agreement between HbA1c and the oral glucose tolerance test (OGTT), bodyweight has not been fully evaluated. The aims of the present study were to evaluate the impact of HbA1c criteria to diagnose diabetes and prediabetes compared with OGTT, and to examine HbA1c in relation to body mass index. MATERIALS AND METHODS: Two cohorts were studied, one from an obesity clinic (n = 592) and one from subjects undergoing screening for diabetes (n = 462). All underwent OGTT and HbA1c measurement. RESULTS: In the obese cohort, HbA1c ≥6.5% (≥48 mmol/mol) showed a sensitivity of 69.3% for diabetes, whereas HbA1c 5.7-6.4% (39-46 mmol/mol) did not identify prediabetes well (sensitivity 39.1%). In the diabetes screening cohort, HbA1c had low sensitivities for both diabetes (39.2%) and prediabetes (53.3%). When participants were stratified according to body mass index class I-III, HbA1c agreement with the OGTT for diabetes was much higher (80%, P < 0.005) in class I obesity compared with class II-III obesity; whereas for prediabetes, HbA1c had a low sensitivity in all obesity classes. CONCLUSIONS: The agreement between HbA1c, fasting plasma glucose and 2-h glucose post-OGTT for the diagnosis of prediabetes was poor in our Italian population; whereas HbA1c ≥6.5% showed a relatively good agreement with OGTT for the diagnosis of diabetes. For the first time, we have shown that obesity class influences the diagnostic performance of HbA1c.

High normal post-load plasma glucose, cardiometabolic risk factors and signs of organ damage in obese children.

OBJECTIVE: To evaluate normoglycemic overweight/obese (Ow/Ob) children whose post-load plasma glucose (2hPG) cut-point may be significantly associated with cardiometabolic risk factors (CMRFs) and whether this cut-point predicts preclinical signs of organ damage. METHODS: One thousand seven hundred and thrity four normoglycemic Ow/Ob children were stratified into quintiles of 2hPG, the sixth group was constituted by 101 children with impaired glucose tolerance (IGT). RESULTS: Moving from the lower quintiles of 2hPG to IGT, the groups differed for Prepubertal stage, BMI, fasting PG, insulin levels, blood pressure, and lipids. To evaluate the best cut-off of 2hPG related to CMRFs, the area under the receiver operating characteristic curve and the Youden's index was calculated. Insulin resistance, high blood pressure, and high triglyceride/HDL-C ratio were associated with a 2hPG cut-off of 110 mg/dl. Children with 2hPG ≥110 mg/dl showed 1.3-3.2 fold higher risk to have high levels of ALT (as surrogate of nonalcoholic fatty liver disease) or increased carotid intima-media thickness. CONCLUSIONS: This study, performed in a large cohort of Ow/Ob children, shows that an atherogenic risk profile and preclinical signs of organ damage are associated with post-challenge elevations in plasma glucose still considered in the high normal range.

Association of RXR-Gamma Gene Variants with Familial Combined Hyperlipidemia: Genotype and Haplotype Analysis.

Background. Familial combined hyperlipidemia (FCHL), the most common genetic form of hyperlipdemia, is characterized by a strong familial clustering and by premature coronary heart disease. The FCHL locus has been mapped to human chromosome 1q21-q23. This region includes the retinoid X receptor gamma (RXRG), a nuclear factor member of the RXR superfamily, which plays important roles in lipid homeostasis. Objective. To investigate the possible role of the RXRG gene in the genetic susceptibility to FCHL. Methods. Variations in RXRG gene were searched by direct sequencing, and the identified SNPs were genotyped by PCR-RFLP in 192 FCHL individuals from 74 families and in 119 controls. Results. We identified 5 polymorphisms in the RXRG gene (rs1128977, rs2651860, rs2134095, rs283696, and rs10918169). Genotyping showed that the A-allele of rs283696 SNP was significantly associated with FCHL (corrected P, P c < 0.01). Also the alleles of the rs10918169 and of the rs2651860 SNP were more frequent in FCHL subjects compared to those in controls, although not significantly after correction. When the clinical characteristics of the FCHL subjects were stratified by allele carrier status for each SNP, the rs2651860 SNP was significantly associated with increased levels of LDL-cholesterol and of Apo-B in T-allele carriers (P < 0.04). Finally, haplotypes analysis with all 5 SNPs confirmed the significant association of RXRG gene with FCHL. Specifically, the haplotype containing all 3 "at-risk" alleles, significantly associated with FCHL (A-allele of rs283696, G-allele of rs10918169, and T-allele of rs2651860), showed an OR (Odds Ratio) of 2.02, P c < 0.048. Conversely, the haplotype without all these 3 alleles was associated with a reduced risk for FCHL (OR = 0.39, P c < 0.023). The "at-risk" haplotype CTTAG was also associated with higher LDL-C (P < 0.015). In conclusion, variation in the RXRG gene may contribute to the genetic dyslipidemia in FCHL subjects.

The COBLL1 C allele is associated with lower serum insulin levels and lower insulin resistance in overweight and obese children.

BACKGROUND: Childhood obesity is a growing epidemic worldwide, and it is associated with metabolic complications, such as insulin resistance. Recently, a genetic variation (rs7607980) in the COBLL1 gene has been associated with lower insulin resistance in adults. The aim of the study was to investigate if the association between COBLL1 rs7607980 genetic variant and lower insulin resistance was present early in life. METHODS: This sequence variant was genotyped in 878 overweight and obese children (mean age: 10 years) from Sardinia, Italy, from the outpatient clinic of the Pediatric Endocrine Unit, at the Regional Hospital for Microcitaemia in Cagliari. Insulin resistance was assessed by measurement of fasting circulating insulin levels before and after an oral glucose tolerance test and by HOMA-IR. RESULTS: The COBLL1 rs7607980 C allele was associated with lower fasting insulin and HOMA-IR levels (p = 0.002 and p = 0.035, respectively) in overweight and obese children. Importantly, lower insulin levels were also observed 2 h after oral glucose tolerance test in C allele carriers (p = 0.009). CONCLUSIONS: The present study shows for the first time, the association between COBLL1 rs7607980 C allele, lower serum insulin levels and lower insulin resistance in overweight and obese children.

Altered glucose homeostasis is associated with increased serum apelin levels in type 2 diabetes mellitus.

BACKGROUND: Apelin is an adipokine that plays a role in the regulation of glucose homeostasis and in obesity. The relationship between apelin serum concentration and dysmetabolic conditions such as type 2 diabetes (T2D) is still controversial. Aims of our study are: 1) determine the circulating levels of apelin in a large cohort of Italian subjects with T2D, T1D and in non-diabetic controls; 2) identify putative metabolic determinants of modified apelin concentrations, in order to search possible mechanism of apelin control; 3) investigate changes in apelin levels in response to sharp modifications of glucose/insulin metabolism in T2D obese subjects before and 3 days after bariatric surgery. METHODS: We recruited 369 subjects, 119 with T2D, 113 with T1D and 137 non-diabetic controls. All subjects underwent a complete clinical examination, including anthropometric and laboratory measurements. Serum apelin levels were determined by EIA (immunoenzyme assay). RESULTS: Patients with T2D had significantly higher serum apelin levels compared to controls (1.23 ± 1.1 ng/mL vs 0.91 ± 0.7 ng/mL, P<0.001) and to T1D subjects (0.73 ± 0.39 ng/mL, P<0.001). Controls and T1D subjects did not differ significantly in apelin levels. Apelin concentrations were directly associated with fasting blood glucose (FBG), body mass index (BMI), basal Disposition Index (DI-0), age, and diagnosis of T2D at bivariate correlation analysis. Multiple regression analysis confirmed that diagnosis of T2D, basal DI-0 and FBG were all determinants of serum apelin levels independently from age and BMI. Bariatric surgery performed in a subgroup of obese diabetic subjects (n = 12) resulted in a significant reduction of apelin concentrations compared to baseline levels (P = 0.01). CONCLUSIONS: Our study demonstrates that T2D, but not T1D, is associated with increased serum apelin levels compared to non-diabetic subjects. This association is dependent on impaired glucose homeostasis, and disappears after bariatric surgery, providing further evidence regarding the relationship between apelin and the regulation of glucose metabolism.

Association of FTO polymorphisms with early age of obesity in obese Italian subjects.

Obesity is recognized as a major health problem worldwide. Genetic factors play a major role in obesity, and genomewide association studies have provided evidence that several common variants within the fat mass- and obesity-associated (FTO) gene are significantly associated with obesity. Very limited data is available on FTO in the Italian population. Aims of our study are to investigate: (1) the association of FTO gene SNPs rs9939609 and rs9930506 with body mass index (BMI) and obesity-related parameters in a large cohort (n = 752) of Italian obese subjects; (2) the association between the two FTO SNPs and age of onset of obesity. Our results demonstrate a strong association between FTO SNPs rs9939609 (P < 0.043) and rs9930506 (P < 0.029) with BMI in the Italian population. FTO rs9930506 was significantly associated with higher BMI in a G allele dose-dependent manner (BMI + 1.4 kg/m² per G allele). We also observed that the association with BMI of the two FTO variants varied with age, with the carriers of the risk alleles developing an increase in body weight earlier in life. In conclusion, our study further demonstrates a role of the genetic variability in FTO on BMI in a large Italian population.

Lack of effect of apolipoprotein C3 polymorphisms on indices of liver steatosis, lipid profile and insulin resistance in obese Southern Europeans.

BACKGROUND: Apolipoprotein C3 (APOC3) is a component of triglyceride-rich lipoproteins, and APOC3 rs2854116 and rs2854117 polymorphisms have been associated with non-alcoholic fatty liver disease, hypertriglyceridaemia, and insulin-resistance. OBJECTIVE: To determine if the APOC3 variants alter the susceptibility of obese subjects to develop liver damage, hypertrigliceridaemia, and insulin-resistance. METHODS: The study was carried out on 585 unrelated obese Italians (median body mass index BMI = 41 kg/m2) who were genotyped for the rs2854116 and rs2854117 variants. All participants underwent oral glucose tolerance tests (OGTT), with measurement of glucose, insulin, lipid parameters. Indices of insulin-resistance (HOMA and ISI) were calculated. Alanine transaminase (ALT) and aspartate transaminase (AST) were used as markers of liver injury. RESULTS: The study subjects were divided into two groups: those homozygous for the wild-type alleles at both SNPs (-482C and -455T alleles) and those who were carriers of at least one variant allele or both (-482T, -455C or both). Also each SNP was analysed independently. No significant differences were found in ALT and AST levels and in the lipid profile between the two groups. Insulin concentrations, glucose tolerance and insulin sensitivity were similar in the two groups. CONCLUSION: We did not identify any significant association between APOC3 polymorphisms and fatty liver disease, lipids, and insulin-resistance in obese subjects, thus not confirming the suggested role of these APOC3 gene sequence variants.

The 148M allele of the PNPLA3 gene is associated with indices of liver damage early in life.

BACKGROUND & AIMS: Childhood obesity is a growing problem worldwide. Non-alcoholic fatty liver disease (NAFLD) is frequently associated with obesity in children. Recently, the PNPLA3 gene I148M (rs738409) variant was demonstrated to be strongly associated with hepatic steatosis in obese adults. In this study we add further insight into the role of PNPLA3 by exploring whether this association begins early in life in obese children or becomes manifest only in adulthood. METHODS: Four hundred and seventy-five obese/overweight children and adolescents were genotyped for the I148M allele. Clinical and biochemical parameters were collected for all participants, including indices of hepatic injury, glucose tolerance and insulin resistance. Ultrasound imaging of the liver was obtained to assess the degree of steatosis in a subset of children. RESULTS: Carriers of two 148M alleles had a 52% increase in circulating ALT levels compared to carriers of two 148I alleles, with individuals with one 148M allele showing a 9.5% increase (p=0.001). AST concentration was also significantly higher in carriers of two and one M alleles (17.4% and 4%, respectively, p=0.022). A total of 36% of carries of two 148M alleles showed elevated ALT, defined as >30U/L, compared to only 10% of carriers of two 148I alleles (p<0.001). Liver steatosis was more prevalent in carriers of two 148M alleles. Glucose tolerance and insulin sensitivity were similar across all three genotypes. CONCLUSIONS: Our data show that the PNPLA3 gene I148M variant is associated with increased levels of ALT/AST in obese children and adolescents, suggesting that it confers genetic susceptibility to liver damage from a young age.

Prevalence of type 1 diabetes autoantibodies (GADA, IA2, and IAA) in overweight and obese children.

OBJECTIVE: Little is known about the prevalence of beta-cell autoantibodies in children with excess body weight. The prevalence of type 1 diabetes autoantibodies and its relation with hyperglycemia was analyzed in 686 overweight/obese children and adolescents. RESEARCH DESIGN AND METHODS: All children underwent an oral glucose tolerance test, and anti-GAD, anti-IA2, and anti-IAA autoantibodies were measured. Autoantibody prevalence was evaluated in 107 normal-weight children for comparison. RESULTS: A single autoantibody was present in 2.18% of overweight/obese subjects and 1.86% normal-weight subjects (P = NS). Postload glycemia was significantly higher in antibody-positive children (133 +/- 69.9 vs. 105.4 +/- 17.7 mg/dl, P < 0.0001) compared with autoantibody-negative subjects. No difference in autoantibody distribution was seen when our cohort was stratified by age, sex, SDS-BMI, pubertal stage, and homeostasis model assessment-insulin resistance (HOMA-IR). CONCLUSIONS: The 2.18% prevalence of type 1 diabetes autoantibodies is similar to that reported in nonobese children. This study provided evidence that excess body weight and insulin resistance do not influence autoantibody frequency.

Oral glucose tolerance test in Italian overweight/obese children and adolescents results in a very high prevalence of impaired fasting glycaemia, but not of diabetes.

BACKGROUND: Very few studies on glucose abnormalities in European overweight/obese children and adolescents are available, and scientific evidence on the value of standard oral glucose tolerance test (OGTT) in childhood is lacking. We therefore aimed to establish prevalence and features of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes (T2D) in a large cohort of Italian overweight/obese children and adolescents and to assess the validity of standard OGTT in the paediatric population. METHODS: This is a 1-year observational study conducted on 736 (535 overweight/obese and 201 normal weight) consecutive paediatric patients attending the outpatient clinic of Paediatric Endocrine Unit. Clinical and biochemical parameters were collected for all participants. All overweight/obese subjects underwent OGTT. RESULTS: We observed a high prevalence of IFG (7.66%), more than twice that observed in other European children, but a low prevalence of IGT (3.18%) and T2D (0.18%). IFG was useless to predict IGT, having very low predictive value (7.3%) and sensitivity (17.6%). Compared to normal weight children, overweight/obese subjects showed significant differences in most metabolic and clinical parameters. In the overweight/obese group, having hyperglycaemia was associated to significantly higher blood pressure, homeostasis model assessment for insulin resistance, insulin and triglycerides. CONCLUSIONS: In our children, the prevalence of IFG is higher than that reported in other European cohorts, whereas T2D is rare. IFG appears not useful to detect IGT in childhood. Paediatric diagnostic cut-points, glucose load and timing of sampling need to be further validated to define glucose abnormalities in obese children that, compared with normal weight subjects, already are characterised by a different metabolic phenotype.

Assessment of adiponectin and leptin as biomarkers of positive metabolic outcomes after lifestyle intervention in overweight and obese children.

BACKGROUND: A number of metabolic changes are caused by childhood obesity, including insulin resistance, diabetes, and dyslipidemia. To counteract them, lifestyle modification with changes in dietary habits and physical activity is the primary intervention. Anthropometric parameters may not identify all positive changes associated with lifestyle modifications, whereas circulating adipokines may represent an alternative as biomarkers. The aim of this study was to evaluate adiponectin and leptin levels as markers of positive metabolic outcomes in childhood obesity. METHODS: Changes in clinical, anthropometric, and metabolic parameters, including adiponectin and leptin, were assessed in 104 overweight and obese children before and after 1 yr of lifestyle intervention. Obesity and overweight were defined according to the Italian body mass index reference tables for age and sex. Fifty-four normal-weight children were evaluated as controls. Forty-eight of the children (47.5%) returned for follow-up at 1 yr. RESULTS: Compared with normal-weight children, overweight and obese subjects differed significantly at baseline for glycemia, insulinemia, homeostasis model assessment for insulin resistance, adiponectinemia (5.8 vs. 18.2 microg/ml in controls), low-density lipoprotein-cholesterol, and triglycerides. These parameters were all higher in the overweight/obese children. At follow-up, most parameters improved in overweight/obese children. The most significant changes were observed in adiponectin concentration, which increased by 245% (P < 0.0001), reaching the levels observed in normal-weight children. Leptin levels showed changes unrelated to positive metabolic outcomes, remaining high at 1 yr of follow-up in overweight/obese children. Regardless of changes in weight status, children with lifestyle intervention reported changes in homeostasis model assessment for insulin resistance and in adiponectin that were associated with loss of fat mass. CONCLUSIONS: After lifestyle intervention, adiponectin increased regardless of changes in weight, whereas no consistent changes was observed in serum leptin. Therefore, circulating adiponectin may represent a good biomarker to evaluate the efficacy of lifestyle intervention in overweight/obese children.