Effects of a 12-Week Lifestyle Intervention on Novel Biomarkers for Type 2 Diabetes (T2D) in Obese Latino Youth

In obese non-diabetic youth, glucose response curve (GRC) and 1-hr glucose concentration during an oral glucose tolerance test (OGTT) represent novel biomarkers for T2D risk. Obese youth with monophasic- vs. biphasic-GRC and 1-hr glucose concentration of ≥155 (Above155) vs. <155 mg/dL (Below155) are at increased risk for T2D. However, to date, it is unknown whether these OGTT-derived phenotypes can be improved in response to any interventions, thereby hindering their practical use as indicators of intervention effectiveness. The purpose of this was to investigate the effects of lifestyle intervention on OGTT-GRC and 1-hr glucose concentration in obese Latino youth at increased risk for T2D. Sixteen obese Latino youth (age 15.6±0.9 years; 7M/9F; body mass index %tile=98.3±1.2) completed a 12-week lifestyle intervention that included weekly nutrition education and 180 minutes of moderate-vigorous exercise per week. All participants completed a 2-hr OGTT before and after the lifestyle intervention to assess changes in OGTT-GRC & 1-hr glucose as well as other pathophysiological risk factors including insulin sensitivity index, insulinogenic index, and oral disposition index (oDI). Chi-square and paired t test were used to compare changes in response to the intervention. At baseline, the prevalence of biphasic-GRC and Below155 was 12.5% and 43.8%, respectively. After the 12-week intervention, OGTT-derived phenotypes were improved, exhibiting significant increases in the prevalence of biphasic-GRC (37.5%, P=0.05) and Below155 (75%, P=0.042). Together with improvement on GRC and 1-hr glucose, oDI was enhanced (Pre: 7.36 ± 6.20 vs. Post: 8.16 ± 5.13, P<0.05), despite no improvement in insulin sensitivity index and insulinogenic index. A 12-week lifestyle intervention is efficacious in improving glucose response curve and 1-hr glucose concentration during an OGTT in conjunction with ß-cell improvement in obese Latino youth. Our data further suggest that these emerging T2D risk biomarkers have prospective utility in terms of assessing change following interventions/therapeutic trials.

Mifepristone Improves Adipose Tissue Insulin Sensitivity in Insulin Resistant Individuals

Background Increased tissue cortisol availability has been implicated in abnormal glucose and fat metabolism in patients with obesity, metabolic syndrome, and type 2 diabetes (T2DM). Our objective was to evaluate whether blockade of glucocorticoid receptor (GR) with mifepristone ameliorates insulin resistance (IR) in overweight/obese subjects with glucose intolerance. Methods We conducted a randomized, double-blinded, placebo-controlled, crossover study in overweight/obese individuals (n = 16, 44% female) with prediabetes or mild T2DM but not clinical hypercortisolism. Mifepristone (50 mg every 6 h) or placebo was administered for 9 days, followed by crossover to the other treatment arm after a washout period of 6 to 8weeks. At baseline and following each treatment, oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test (FSIVGTT) were performed. Insulin sensitivity was measured using FSIVGTT [primary outcome: insulin sensitivity index (SI)] and OGTT [Matsuda index (MI) and oral glucose insulin sensitivity index (OGIS)]. Hepatic and adipose insulin resistance were assessed using hepatic insulin resistance index (HIRI), and adipose tissue insulin sensitivity index (Adipo-SI) and adipo-IR, derived from the FSIVGTT. Results Mifepristone administration did not alter whole-body glucose disposal indices of insulin sensitivity (SI, MI, and OGIS). GR blockade significantly improved Adipo-SI (61.7 ± 32.9 vs 42.8 ± 23.9; P = 0.002) and reduced adipo-IR (49.9 ± 45.9 vs 65.5 ± 43.8; P = 0.004), and HIRI (50.2 ± 38.7 vs 70.0 ± 44.3; P = 0.08). Mifepristone increased insulin clearance but did not affect insulin secretion or β-cell glucose sensitivity. Conclusion Short-term mifepristone administration improves adipose and hepatic insulin sensitivity among obese individuals with hyperglycemia without hypercortisolism.

The association of hyperglycaemia and insulin resistance with incident depressive symptoms over 4 years of follow-up: The Maastricht Study

Aims/hypothesis Depression is twice as common in individuals with type 2 diabetes as in the general population. However, it remains unclear whether hyperglycaemia and insulin resistance are directly involved in the aetiology of depression. Therefore, we investigated the association of markers of hyperglycaemia and insulin resistance, measured as continuous variables, with incident depressive symptoms over 4 years of follow-up. Methods We used data from the longitudinal population-based Maastricht Study (n = 2848; mean age 59.9 ± 8.1 years, 48.8% women, 265 incident depression cases, 10,932 person-years of follow-up). We assessed hyperglycaemia by fasting and 2 h post-load OGTT glucose levels, HbA1c and skin autofluorescence (reflecting AGEs) at baseline. We used the Matsuda insulin sensitivity index and HOMA-IR to calculate insulin resistance at baseline. Depressive symptoms (nine-item Patient Health Questionnaire score ≥10) were assessed at baseline and annually over 4 years. We used Cox regression analyses, and adjusted for demographic, cardiovascular and lifestyle risk factors. Results Fasting plasma glucose, 2 h post-load glucose and HbA1c levels were associated with an increased risk for incident depressive symptoms after full adjustment (HR 1.20 [95% CI 1.08, 1.33]; HR 1.25 [1.08, 1.44]; and HR 1.22 [1.09, 1.37] per SD, respectively), while skin autofluorescence, insulin sensitivity index and HOMA-IR were not (HR 0.99 [0.86, 1.13]; HR 1.02 [0.85, 1.25]; and HR 0.93 [0.81, 1.08], per SD, respectively). Conclusions/interpretation The observed temporal association between hyperglycaemia and incident depressive symptoms in this study supports the presence of a mechanistic link between hyperglycaemia and the development of depressive symptoms.

184 Insulin Sensitivity and Glucose Metabolism of Olanzapine and Combination Olanzapine and Samidorphan: A Phase 1 Exploratory Study in Healthy Volunteers

Background:A combination of olanzapine and samidorphan (OLZ/SAM) is in development for schizophrenia to provide the efficacy of olanzapine while mitigating olanzapine-associated weight gain. The objective of this phase 1 exploratory study was to assess metabolic treatment effects of OLZ/SAM.Methods:Healthy, non-obese adults (18–40 years) were randomized 2:2:1 to once-daily OLZ/SAM, olanzapine, or placebo for 21 days. Assessments included oral glucose tolerance test (OGTT), hyperinsulinemic-euglycemic clamp, weight gain, and adverse event (AE) monitoring. Treatment effects were estimated with analysis of covariance.Results:Sixty subjects were randomized (OLZ/SAM, n=24; olanzapine, n=24; placebo, n=12); 19 (79.2%), 22 (91.7%), and 11 (91.7%), respectively, completed the study. In the OGTT, olanzapine led to significant hyperinsulinemia (P<0.0001) and significantly reduced insulin sensitivity (2-hour Matsuda index) at day 19 vs baseline (P=0.0012), changes not observed with OLZ/SAM. No significant between-group differences were observed for change from baseline in clamp-derived insulin sensitivity index at day 21. Least squares mean weight change from baseline was similar with OLZ/SAM (3.16 kg) and olanzapine (2.87 kg); both were significantly higher than placebo (0.57 kg; both P<0.01). Caloric intake significantly decreased from baseline to day 22 with OLZ/SAM (P=0.015) but not with olanzapine or placebo. Forty-nine subjects (81.7%) experienced ≥1 AE (OLZ/SAM, 87.5%; olanzapine, 79.2%; placebo, 75.0%).Conclusions:In this exploratory study, hyperinsulinemia and decreased insulin sensitivity were observed in the OGTT with olanzapine but not with OLZ/SAM or placebo. Clamp-derived insulin sensitivity index and weight changes were similar with OLZ/SAM and olanzapine in healthy subjects during the 3-week study.Funding Acknowledgements:This study was funded by Alkermes, Inc.

Mitochondrial mutation m.3243A>G associates with insulin resistance in non-diabetic carriers

Aim This case–control study aimed to examine impairments in glucose metabolism in non-diabetic carriers of the mitochondrial mutation m.3243A>G by evaluating insulin secretion capacity and sensitivity. Methods Glucose metabolism was investigated in 23 non-diabetic m.3243A>G carriers and age-, sex- and BMI-matched healthy controls with an extended 4-h oral glucose tolerance test (OGTT). Insulin sensitivity index and acute insulin response were estimated on the basis of the OGTT. This was accompanied by examination of body composition by dual-energy X-ray absorptiometry (DXA), maximum aerobic capacity and a Recent Physical Activity Questionnaire (RPAQ). Results Fasting p-glucose, s-insulin and s-c-peptide levels did not differ between m.3243A>G carriers and controls. Insulin sensitivity index (BIGTT-S1) was significantly lower in the m.3243A>G carriers, but there was no difference in the acute insulin response between groups. P-lactate levels were higher in carriers throughout the OGTT. VO2max, but not BMI, waist and hip circumferences, lean and fat body mass%, MET or grip strength, was lower in mutation carriers. BIGTT-S1 remained lower in mutation carriers after adjustment for multiple confounding factors including VO2max in regression analyses. Conclusions Glucose metabolism in m.3243A>G carriers was characterized by reduced insulin sensitivity, which could represent the earliest phase in the pathogenesis of m.3243A>G-associated diabetes.

Insulin Sensitivity Is Associated with Lipoprotein Lipase (LPL) and Catenin Delta 2 (CTNND2) DNA Methylation in Peripheral White Blood Cells in Non-Diabetic Young Women

Hyperglycaemia and type 2 diabetes (T2D) are associated with impaired insulin secretion and/or insulin action. Since few studies have addressed the relation between DNA methylation patterns with elaborated surrogates of insulin secretion/sensitivity based on the intravenous glucose tolerance test (IVGTT), the aim of this study was to evaluate the association between DNA methylation and an insulin sensitivity index based on IVGTT (calculated insulin sensitivity index (CSi)) in peripheral white blood cells from 57 non-diabetic female volunteers. The CSi and acute insulin response (AIR) indexes, as well as the disposition index (DI = CSi × AIR), were estimated from abbreviated IVGTT in 49 apparently healthy Chilean women. Methylation levels were assessed using the Illumina Infinium Human Methylation 450k BeadChip. After a statistical probe filtering, the two top CpGs whose methylation was associated with CSi were cg04615668 and cg07263235, located in the catenin delta 2 (CTNND2) and lipoprotein lipase (LPL) genes, respectively. Both CpGs conjointly predicted insulin sensitivity status with an area under the curve of 0.90. Additionally, cg04615668 correlated with homeostasis model assessment insulin-sensitivity (HOMA-S) and AIR, whereas cg07263235 was associated with plasma creatinine and DI. These results add further insights into the epigenetic regulation of insulin sensitivity and associated complications, pointing the CTNND2 and LPL genes as potential underlying epigenetic biomarkers for future risk of insulin-related diseases.

Inflammatory markers predict insulin sensitivity in active rheumatoid arthritis but not in psoriatic arthritis

Whether the insulin resistance commonly observed in patients with inflammatory arthritis is a disease-specific feature and/or is limited to a disease phase (i.e., it occurs only during phases of high disease activity) is unknown. Fifty-three rheumatoid arthritis (RA) and 44 psoriatic arthritis (PsA) patients were recruited consecutively along with 194 controls matched for age, sex and body mass index for a case-control study. All underwent an oral glucose tolerance test, the results of which were analysed to derive the following indexes: homeostatic model of insulin resistance (HOMA-IR), insulin sensitivity index (ISI) and early insulin sensitivity index (EISI). These data were related to anthropometric, clinical and laboratory findings. Metabolic parameters of patients and controls were similar. Neither inflammatory markers nor disease activity scores were related to glucose metabolism for the generality of RA and PsA patients; however, by restricting the analysis to the subset of RA patients with residual disease activity, an association emerged between erythrocyte sedimentation rate, on the one hand, and fasting insulin (β=0.46, p=0.047) and HOMA-IR (β=0.44, p=0.02), on the other. Moreover, C-reactive protein (CRP) levels were associated with plasma glucose and insulin levels measured 120 min after the glucose load (β=0.91, p=0.0003 and β=0.77, p=0.0006, respectively); ISI and EISI were predicted by CRP (β=-0.79, p=0.0006; β=-0.80, p=0.0001, respectively). The same did not hold true for PsA patients. The association between systemic inflammation and insulin resistance indexes is a feature of RA with residual disease activity, not a universal feature of inflammatory arthritides.