Adolescents with obesity treated with exenatide maintain endogenous GLP-1, reduce DPP-4, and improve glycemic control

BackgroundGLP-1 receptor agonists (GLP-1RA) are increasingly used to treat adolescent obesity. However, the effect on endogenous GLP-1 secretory patterns following treatment in adolescents is unknown. The GLP-1RA exenatide was shown to significantly lower BMI and 2-hour glucose in adolescents with obesity, in the placebo-controlled, randomized controlled trial Combat-JUDO. The aim of this study was to evaluate effects of weekly injections of 2 mg exenatide extended release on secretory patterns of endogenous hormones during OGTT.Subjects and MeasurementsThis study was a pre-planned sub-study of the Combat-JUDO trial, set at the Pediatric clinic at Uppsala University Hospital, Sweden and Paracelsus Medical University, Austria. 44 adolescents with obesity were included and randomized 1:1 to treatment:placebo. 19 patients in the treatment group and 18 in the placebo group completed the trial. Before and after treatment, GLP-1, glucose, insulin, glucagon and glicentin levels were measured during OGTT; DPP-4 and proinsulin were measured at fasting. A per-protocol approach was used in the analyses.ResultsExenatide treatment did not affect GLP-1 levels during OGTT. Treatment significantly lowered DPP-4, proinsulin and the proinsulin-to-insulin ratio at fasting, increased glicentin levels but did not affect insulin, C-peptide or glucagon levels during OGTT.ConclusionWeekly s.c. injections with 2 mg of exenatide maintains endogenous total GLP-1 levels and lowers circulating DPP-4 levels. This adds an argument in favor of using exenatide in the treatment of pediatric obesity.Clinical trial registrationclinicaltrials.gov, identifier NCT0279440

Impaired Glucose Tolerance in Childhood Obesity : Contribution of Glucagon, GLP-1 and Inflammation

In the wake of increased obesity prevalence, impaired glucose tolerance (IGT) and type 2 diabetes (T2D) in childhood and adolescence is increasingly common. Given the negative impacts these conditions have on health over time, understanding the pathophysiology in those affected early in life is important. Both the proglucagon-derived peptides and low-grade inflammation have been implicated in the development of obesity-related complications. The aim of this thesis was to study across the glucose tolerance spectrum in children and adolescents with obesity 1) proglucagon-derived peptides glucagon, GLP-1 and glicentin, 2) dipeptidyl peptidase-4 (DPP-4) and its degradation of GLP-1 and 3) novel inflammatory markers. To this end, children and adolescents of the Uppsala Longitudinal Study of Childhood Obesity were studied.    Children and adolescents with obesity had higher fasting plasma glucagon concentrations than lean controls. In particular visceral adiposity, hyperinsulinemia, triglycerides and free fatty acids (FFAs) were associated with high plasma glucagon concentrations. In isolated islets elevated FFAs caused hypersecretion of glucagon. In children and adolescents with IGT or T2D, fasting plasma glucagon was further elevated and the GLP-1 and glicentin response to an oral glucose tolerance test (OGTT) was decreased. In T2D plasma glucagon increased during the first 15 minutes of OGTT. Plasma DPP-4 concentrations were elevated in obesity and associated with lower proportion of intact GLP-1 but not with IGT. Several pro-inflammatory markers were elevated in children and adolescents with obesity but not further elevated in IGT or T2D with the exception of low plasma Tumor necrosis factor-related weak inducer of apoptosis (TWEAK) levels, which were associated with IGT, hyperinsulinemia and hyperglucagonemia. High plasma hepatocyte growth factor (HGF) concentration was associated with increased risk of further weight gain in children and adolescents with obesity. In conclusion, elevated glucagon concentration at fasting, a hyperglucagonemic response to OGTT and reduced GLP-1 and glicentin are characteristics of IGT and T2D development in childhood obesity reflecting altered usage of the proglucagon gene. DPP-4 concentrations are elevated in childhood obesity but not associated with IGT. Reduced circulating TWEAK was identified as a novel marker of IGT early in life. Children with obesity and high HGF are less likely to respond well to lifestyle intervention

Impaired Glucose Tolerance in Childhood Obesity : Contribution of Glucagon, GLP-1 and Inflammation

In the wake of increased obesity prevalence, impaired glucose tolerance (IGT) and type 2 diabetes (T2D) in childhood and adolescence is increasingly common. Given the negative impacts these conditions have on health over time, understanding the pathophysiology in those affected early in life is important. Both the proglucagon-derived peptides and low-grade inflammation have been implicated in the development of obesity-related complications. The aim of this thesis was to study across the glucose tolerance spectrum in children and adolescents with obesity 1) proglucagon-derived peptides glucagon, GLP-1 and glicentin, 2) dipeptidyl peptidase-4 (DPP-4) and its degradation of GLP-1 and 3) novel inflammatory markers. To this end, children and adolescents of the Uppsala Longitudinal Study of Childhood Obesity were studied.    Children and adolescents with obesity had higher fasting plasma glucagon concentrations than lean controls. In particular visceral adiposity, hyperinsulinemia, triglycerides and free fatty acids (FFAs) were associated with high plasma glucagon concentrations. In isolated islets elevated FFAs caused hypersecretion of glucagon. In children and adolescents with IGT or T2D, fasting plasma glucagon was further elevated and the GLP-1 and glicentin response to an oral glucose tolerance test (OGTT) was decreased. In T2D plasma glucagon increased during the first 15 minutes of OGTT. Plasma DPP-4 concentrations were elevated in obesity and associated with lower proportion of intact GLP-1 but not with IGT. Several pro-inflammatory markers were elevated in children and adolescents with obesity but not further elevated in IGT or T2D with the exception of low plasma Tumor necrosis factor-related weak inducer of apoptosis (TWEAK) levels, which were associated with IGT, hyperinsulinemia and hyperglucagonemia. High plasma hepatocyte growth factor (HGF) concentration was associated with increased risk of further weight gain in children and adolescents with obesity. In conclusion, elevated glucagon concentration at fasting, a hyperglucagonemic response to OGTT and reduced GLP-1 and glicentin are characteristics of IGT and T2D development in childhood obesity reflecting altered usage of the proglucagon gene. DPP-4 concentrations are elevated in childhood obesity but not associated with IGT. Reduced circulating TWEAK was identified as a novel marker of IGT early in life. Children with obesity and high HGF are less likely to respond well to lifestyle intervention

Altered mitochondrial metabolism in peripheral blood cells from patients with inborn errors of β-oxidation

Inborn errors of mitochondrial fatty acid oxidation (FAO), such as medium-chain acyl-CoA dehydrogenase deficiency (MCAD) and very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) affects cellular function and whole-body metabolism. Carnitine uptake deficiency (CUD) disturbs the transportation of fatty acids into the mitochondria, but when treated is a mild disease without significant effects on FAO. For improved clinical care of VLCAD in particular, estimation of FAO severity could be important. We have investigated whether the oxygen consumption rate (OCR) of peripheral blood mononuclear cells (PBMCs) obtained from patients with MCAD, VLCAD, and CUD can be used to study cellular metabolism in patients with FAO defects and to determine the severity of FAO impairment. PBMCs were isolated from patients with VLCAD (n = 9), MCAD (n = 5–7), and CUD (n = 5). OCR was measured within 6-hours of venous puncture using the Seahorse XFe96. The PBMCs were exposed to glucose alone or with caprylic acid (C8:0) or palmitic acid (C16:0). OCR was significantly lower in cells from patients with β-oxidation deficiencies (MCAD and VLCAD) compared to CUD at basal conditions. When exposed to C16:0, OCR in VLCAD cells was unchanged, whereas OCR in MCAD cells increased but not to the levels observed in CUD. However, C8:0 did not increase OCR, as would be expected, in VLCAD cells. There was no clear relationship between clinical severity level and OCR. In patients with β-oxidation deficiencies, changes of mitochondrial respiration in PBMCs are detectable, which indicate that PBMCs have translational potential for studies of β-oxidation defects. However, further studies are warranted.Title in Web of Science: Altered mitochondrial metabolism in peripheral blood cells from patients with inborn errors of beta-oxidation</p

Metformin Can Attenuate Beta-Cell Hypersecretion—Implications for Treatment of Children with Obesity

In children with obesity, insulin hypersecretion is proposed to precede insulin resistance. We investigated if metformin could be used to attenuate insulin secretion from palmitate-treated isolated islets and its implication for children with obesity. Human islets were exposed to palmitate for 0.5 or 1 day, when metformin was introduced. After culture, glucose-stimulated insulin secretion (GSIS) was measured. Children with obesity, who had received metformin for over six months (n = 21, age 13.9 ± 1.8), were retrospectively evaluated. Children were classified as either “reducing” or “increasing” based on the difference between AUC0–120 of insulin during OGTT before and after metformin treatment. In human islets, GSIS increased after culture in palmitate for up to 1 day but declined with continued palmitate exposure. Whereas adding metformin after 1 day of palmitate exposure increased GSIS, adding metformin after 0.5 days reduced GSIS. In children with “reducing” insulin AUC0–120 (n = 9), 2 h glucose and triglycerides decreased after metformin treatment, which was not observed in patients with “increasing” insulin AUC0–120 (n = 12). In isolated islets, metformin attenuated insulin hypersecretion if introduced when islet secretory capacity was maintained. In children with obesity, improved glycemic and lipid levels were accompanied by reduced insulin levels during OGTT after metformin treatment

Low Fasting Concentrations of Glucagon in Patients with Very Long-Chain Acyl-CoA Dehydrogenase Deficiency

(1) Background: Deficiencies of mitochondrial fatty acid oxidation (FAO) define a subgroup of inborn errors of metabolism, with medium-chain acyl-CoA dehydrogenase deficiency (MCAD) and very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) being two of the most common. Hypoketotic hypoglycemia is a feared clinical complication and the treatment focuses on avoiding hypoglycemia. In contrast, carnitine uptake deficiency (CUD) is treated as a mild disease without significant effects on FAO. Impaired FAO has experimentally been shown to impair glucagon secretion. Glucagon is an important glucose-mobilizing hormone. If and how glucagon is affected in patients with VLCAD or MCAD remains unknown. (2) Methods: A cross-sectional study was performed with plasma hormone concentrations quantified after four hours of fasting. Patients with VLCAD (n = 10), MCAD (n = 7) and CUD (n = 6) were included. (3) Results: The groups were similar in age, sex, weight, and height. The glucagon and insulin levels were significantly lower in the VLCAD group compared to the CUD group (p &lt; 0.05, respectively). The patients with CUD had glucagon concentrations similar to the normative data. No significant differences were seen in GLP-1, glicentin, glucose, amino acids, or NEFAs. (4) Conclusions: Low fasting concentrations of glucagon are present in patients with VLCAD and cannot be explained by altered stimuli in plasma

Determinants of hyperglucagonemia in pediatric non-alcoholic fatty liver disease

ObjectiveOver the years, non-alcoholic fatty liver (NAFLD) disease has progressed to become the most frequent chronic liver disease in children and adolescents. The full pathology is not yet known, but disease progression leads to cirrhosis and hepatocellular carcinoma. Risk factors included hypercaloric diet, obesity, insulin resistance and genetics. Hyperglucagonemia appears to be a pathophysiological consequence of hepatic steatosis, thus, the hypothesis of the study is that hepatic fat accumulation leads to increased insulin resistance and impaired glucagon metabolism leading to hyperglucagonemia in pediatric NAFLD. Methods132 children and adolescents between 10 and 18 years, with varying degrees of obesity, were included in the study. Using Magnetic Resonance Imaging (MRI) average liver fat was determined, and patients were stratified as NAFLD (&gt;5% liver fat content) and non-NAFLD (&lt;5%). All patients underwent a standardized oral glucose tolerance test (OGTT). Additionally, anthropometric parameters (height, weight, BMI, waist circumference, hip circumference) such as lab data including lipid profile (triglycerides, HDL, LDL), liver function parameters (ALT, AST), uric acid, glucose metabolism (fasting insulin and glucagon, HbA1c, glucose 120 min) and indices evaluating insulin resistance (HIRI, SPISE, HOMA-IR, WBISI) were measured. ResultsChildren and adolescents with NAFLD had significantly higher fasting glucagon values compared to the non-NAFLD cohort (p=0.0079). In the NAFLD cohort univariate analysis of fasting glucagon was associated with BMI-SDS (p&lt;0.01), visceral adipose tissue volume (VAT) (p&lt;0.001), average liver fat content (p&lt;0.001), fasting insulin concentration (p&lt;0.001), triglycerides (p&lt;0.001) and HDL (p=0.034). This correlation equally applied to all insulin indices HOMA-IR, WBISI, HIRI (all p&lt;0.001) and SPISE (p&lt;0.002). Multivariate analysis (R-2 adjusted 0.509) for the same subgroup identified HIRI (p=0.003) and VAT volume (p=0.017) as the best predictors for hyperglucagonemia. Average liver fat content is predictive in pediatric overweight and obesity but not NAFLD. ConclusionsChildren and adolescents with NAFLD have significantly higher fasting plasma glucagon values, which were best predicted by hepatic insulin resistance and visceral adipose tissue, but not average liver fat content

Adolescents with obesity treated with exenatide maintain endogenous GLP-1, reduce DPP-4, and improve glycemic control

Background: GLP-1 receptor agonists (GLP-1RA) are increasingly used to treat adolescent obesity. However, the effect on endogenous GLP-1 secretory patterns following treatment in adolescents is unknown. The GLP-1RA exenatide was shown to significantly lower BMI and 2-hour glucose in adolescents with obesity, in the placebo-controlled, randomized controlled trial Combat-JUDO. The aim of this study was to evaluate effects of weekly injections of 2 mg exenatide extended release on secretory patterns of endogenous hormones during OGTT. Subjects and Measurements: This study was a pre-planned sub-study of the Combat-JUDO trial, set at the Pediatric clinic at Uppsala University Hospital, Sweden and Paracelsus Medical University, Austria. 44 adolescents with obesity were included and randomized 1:1 to treatment:placebo. 19 patients in the treatment group and 18 in the placebo group completed the trial. Before and after treatment, GLP-1, glucose, insulin, glucagon and glicentin levels were measured during OGTT; DPP-4 and proinsulin were measured at fasting. A per-protocol approach was used in the analyses. Results: Exenatide treatment did not affect GLP-1 levels during OGTT. Treatment significantly lowered DPP-4, proinsulin and the proinsulin-to-insulin ratio at fasting, increased glicentin levels but did not affect insulin, C-peptide or glucagon levels during OGTT. Conclusion: Weekly s.c. injections with 2 mg of exenatide maintains endogenous total GLP-1 levels and lowers circulating DPP-4 levels. This adds an argument in favor of using exenatide in the treatment of pediatric obesity

Single Point Insulin Sensitivity Estimator in Pediatric Non-Alcoholic Fatty Liver Disease

BackgroundAttenuated insulin-sensitivity (IS) is a central feature of pediatric non-alcoholic fatty liver disease (NAFLD). We recently developed a new index, single point insulin sensitivity estimator (SPISE), based on triglycerides, high-density-lipoprotein and body-mass-index (BMI), and validated by euglycemic-hyperinsulinemic clamp-test (EHCT) in adolescents. This study aims to assess the performance of SPISE as an estimation of hepatic insulin (in-)sensitivity. Our results introduce SPISE as a novel and inexpensive index of hepatic insulin resistance, superior to established indices in children and adolescents with obesity. Materials and MethodsNinety-nine pubertal subjects with obesity (13.5 +/- 2.0 years, 59.6% males, overall mean BMI-SDS + 2.8 +/- 0.6) were stratified by MRI (magnetic resonance imaging) into a NAFLD (&gt;5% liver-fat-content; male n=41, female n=16) and non-NAFLD (&lt;= 5%; male n=18, female n=24) group. Obesity was defined according to WHO criteria (&gt; 2 BMI-SDS). EHCT were used to determine IS in a subgroup (n=17). Receiver-operating-characteristic (ROC)-curve was performed for diagnostic ability of SPISE, HOMA-IR (homeostatic model assessment for insulin resistance), and HIRI (hepatic insulin resistance index), assuming null hypothesis of no difference in area-under-the-curve (AUC) at 0.5. ResultsSPISE was lower in NAFLD (male: 4.8 +/- 1.2, female: 4.5 +/- 1.1) than in non-NAFLD group (male 6.0 +/- 1.6, female 5.6 +/- 1.5; P&lt; 0.05 {95% confidence interval [CI]: male NAFLD 4.5, 5.2; male non-NAFLD 5.2, 6.8; female NAFLD 4.0, 5.1, female non-NAFLD 5.0, 6.2}). In males, ROC-AUC was 0.71 for SPISE (P=0.006, 95% CI: 0.54, 0.87), 0.68 for HOMA-IR (P=0.038, 95% CI: 0.48, 0.88), and 0.50 for HIRI (P=0.543, 95% CI: 0.27, 0.74). In females, ROC-AUC was 0.74 for SPISE (P=0.006), 0.59 for HOMA-IR (P=0.214), and 0.68 for HIRI (P=0.072). The optimal cutoff-level for SPISE between NAFLD and non-NAFLD patients was 5.18 overall (Youden-index: 0.35; sensitivity 0.68%, specificity 0.67%). ConclusionSPISE is significantly lower in juvenile patients with obesity-associated NAFLD. Our results suggest that SPISE indicates hepatic IR in pediatric NAFLD patients with sensitivity and specificity superior to established indices of hepatic IR