Search

Objective: The extent to which weight loss contributes to increases in insulin sensitivity (IS) and β-cell function after surgical or medical intervention has not been directly compared in individuals with impaired glucose tolerance or newly diagnosed type 2 diabetes., Methods: The Restoring Insulin Secretion (RISE) Study included adults in the Beta-Cell Restoration Through Fat Mitigation Study (n = 88 randomized to laparoscopic gastric banding or metformin [MET]) and the Adult Medication Study (n = 267 randomized to placebo, MET, insulin glargine/MET, or liraglutide + MET [L + M]). IS and β-cell responses were measured at baseline and after 12 months by modeling of oral glucose tolerance tests and during arginine-stimulated hyperglycemic clamps. Linear regression models assessed differences between and within treatments over time., Results: BMI decreased in all treatment groups, except placebo, at 12 months. IS increased in all arms except placebo and was inversely correlated with changes in BMI. L + M was the only treatment arm that enhanced multiple measures of β-cell function independent of weight loss. Insulin secretion decreased in the laparoscopic gastric banding arm proportional to increases in IS, with no net benefit on β-cell function., Conclusions: Reducing demand on the β-cell by improving IS through weight loss does not reverse β-cell dysfunction. L + M was the only treatment that enhanced β-cell function., (© 2022 The Obesity Society.)

Objective: To identify predictors of glycemic worsening among youth and adults with impaired glucose tolerance (IGT) or recently diagnosed type 2 diabetes in the Restoring Insulin Secretion (RISE) Study., Research Design and Methods: A total of 91 youth (10-19 years) were randomized 1:1 to 12 months of metformin (MET) or 3 months of glargine, followed by 9 months of metformin (G-MET), and 267 adults were randomized to MET, G-MET, liraglutide plus MET (LIRA+MET), or placebo for 12 months. All participants underwent a baseline hyperglycemic clamp and a 3-h oral glucose tolerance test (OGTT) at baseline, month 6, month 12, and off treatment at month 15 and month 21. Cox models identified baseline predictors of glycemic worsening (HbA 1c increase ≥0.5% from baseline)., Results: Glycemic worsening occurred in 17.8% of youth versus 7.5% of adults at month 12 ( P = 0.008) and in 36% of youth versus 20% of adults at month 21 ( P = 0.002). In youth, glycemic worsening did not differ by treatment. In adults, month 12 glycemic worsening was less on LIRA+MET versus placebo (hazard ratio 0.21, 95% CI 0.05-0.96, P = 0.044). In both age-groups, lower baseline clamp-derived β-cell responses predicted month 12 and month 21 glycemic worsening ( P < 0.01). Lower baseline OGTT-derived β-cell responses predicted month 21 worsening ( P < 0.05). In youth, higher baseline HbA 1c and 2-h glucose predicted month 12 and month 21 glycemic worsening, and higher fasting glucose predicted month 21 worsening ( P < 0.05). In adults, lower clamp- and OGTT-derived insulin sensitivity predicted month 12 and month 21 worsening ( P < 0.05)., Conclusions: Glycemic worsening was more common among youth than adults with IGT or recently diagnosed type 2 diabetes, predicted by lower baseline β-cell responses in both groups, hyperglycemia in youth, and insulin resistance in adults., (© 2021 by the American Diabetes Association.)

Objective: We examined the glucose response curves (biphasic [BPh], monophasic [MPh], incessant increase [IIn]) during an oral glucose tolerance test (OGTT) and their relationship to insulin sensitivity (IS) and β-cell function (βCF) in youth versus adults with impaired glucose tolerance or recently diagnosed type 2 diabetes.RESEARCH DESIGN AND METHODSThis was both a cross-sectional and a longitudinal evaluation of participants in the RISE study randomized to metformin alone for 12 months or glargine for 3 months followed by metformin for 9 months. At baseline/randomization, OGTTs (85 youth, 353 adults) were categorized as BPh, MPh, or IIn. The relationship of the glucose response curves to hyperglycemic clamp-measured IS and βCF at baseline and the change in glucose response curves 12 months after randomization were assessed.RESULTSAt randomization, the prevalence of the BPh curve was significantly higher in youth than adults (18.8% vs. 8.2%), with no differences in MPh or IIn. IS did not differ across glucose response curves in youth or adults. However, irrespective of curve type, youth had lower IS than adults ( P < 0.05). βCF was lowest in IIn versus MPh and BPh in youth and adults ( P < 0.05), yet compared with adults, youth had higher βCF in BPh and MPh ( P < 0.005) but not IIn. At month 12, the change in glucose response curves did not differ between youth and adults, and there was no treatment effect.CONCLUSIONSDespite a twofold higher prevalence of the more favorable BPh curve in youth at randomization, RISE interventions did not result in beneficial changes in glucose response curves in youth compared with adults. Moreover, the typical β-cell hypersecretion in youth was not present in the IIn curve, emphasizing the severity of β-cell dysfunction in youth with this least favorable glucose response curve., (© 2021 by the American Diabetes Association.)

Background: The RISE Pediatric Medication Study compared strategies for preserving β-cell function, including a 9-month follow-up after treatment withdrawal to test treatment effect durability., Objective: Evaluate OGTT measures of glucose and β-cell response through 12 months of intervention and 9 months of medication washout., Participants: Youth (n = 91) aged 10 to 19 years with BMI ≥85th percentile and impaired glucose tolerance (IGT) or recently diagnosed type 2 diabetes (T2D)., Methods: A multicenter randomized clinical trial comparing insulin glargine for 3 months followed by metformin for 9 months (G→Met) or metformin alone (Met) for 12 months. We report within-group changes from baseline to end of medication intervention (M12), baseline to 9 months post-medication withdrawal (M21), and end of medication (M12) to M21. OGTT C-peptide index [CPI] paired with 1/fasting insulin evaluated β-cell response., Results: At M12, both treatments were associated with stable fasting glucose (G→Met baseline 6.0 ± 0.1 vs M12 5.9 ± 0.2 mmol/L, P = .62; Met baseline 6.1 ± 0.2 vs M12 6.0 ± 0.2 mmol/L, P = .73) and 2-hour glucose (G→Met baseline 10.2 ± 0.4 vs M12 9.3 ± 0.5 mmol/L, P = .03; Met baseline 10.2 ± 0.4 vs M12 10.6 ± 0.6 mmol/L, P = .88). Following medication withdrawal, fasting glucose worsened (G→Met M21 8.6 ± 1.8, P = .004; Met M21 7.8 ± 0.7 mmol/L, P = .003), as did 2-hour glucose (G→Met M21 13.2 ± 1.4, P = .002; Met M21 13.1 ± 1.2 mmol/L, P = .006), associated with declines in β-cell response., Conclusions: G→Met and Met were associated with stable glucose measures during 12 months of treatment in youth with IGT or recently diagnosed T2D. Glucose and β-cell response worsened post-medication withdrawal, suggesting treatment must be long-term or alternative treatments pursued., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: Glycemic control deteriorates more rapidly in youth vs adults. We compared model-derived measures of β-cell function between youth and adults with either impaired glucose tolerance (IGT) or type 2 diabetes to determine if a β-cell defect differentiates these age groups., Methods: This is a cross-sectional analysis of baseline data from the Restoring Insulin Secretion (RISE) Study. Youth (54 Y-IGT, 33 Y-D) and adults (250 A-IGT, 104 A-D) underwent 3-hour oral glucose tolerance tests for modeling of insulin secretion rates (ISRs), glucose sensitivity, and rate sensitivity. Insulin sensitivity was quantified as the glucose infusion rate/insulin (M/I) from a hyperglycemic clamp., Results: Youth had lower insulin sensitivity despite similar body mass index. Analyses were adjusted for insulin sensitivity. Youth had higher basal ISRs (Y-IGT 200 ± 161 vs A-IGT 152 ± 74, P < .001; Y-D 245 ± 2.5 vs A-D 168 ± 115 pmol/min/m 2 , P = .007) and total ISRs (Y-IGT 124 ± 86 vs A-IGT 98 ± 39, P < .001; Y-D 116 ± 110 vs A-D 97 ± 62 nmol/m 2 , P = .002). Within IGT, glucose sensitivity (Y-IGT 140 ± 153 vs A-IGT 112 ± 70 pmol/min/m 2 /mM, P = .004) and rate sensitivity (median[interquartile range]:Y-IGT 2271[1611, 3222] vs A-IGT 1164[685, 1565] pmol/m 2 /mM, P < .001) were higher in youth, but not different by age group within diabetes., Conclusions: Model-derived measures of β-cell function provide additional insight into the pathophysiology of type 2 diabetes in youth with higher ISRs and β-cell secretion more responsive to glucose in youth relative to adults even after adjusting for differences in insulin sensitivity. It is unknown whether these findings in youth reflect β-cells that are healthier or whether this is a defect that contributes to more rapid loss of function., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: Impaired glucose tolerance (IGT) represents a pre-diabetic state. Controversy continues in regards to its pathophysiology. The aim of this study was to investigate the differences in insulin sensitivity (IS) and secretion in obese adolescents with IGT compared with those with normal glucose tolerance (NGT) and type 2 diabetes., Research Design and Methods: A total of 12 obese adolescents with NGT, 19 with IGT, and 17 with type 2 diabetes underwent evaluation of insulin sensitivity (3-h hyperinsulinemic [80 micro/m(2)/min]-euglycemic clamp), first-phase insulin and second-phase insulin secretion (2-h hyperglycemic clamp), body composition, and abdominal adiposity. Glucose disposition index (GDI) was calculated as the product of first-phase insulin x insulin sensitivity., Results: Insulin-stimulated glucose disposal was significantly lower in subjects with type 2 diabetes compared with subjects with NGT and IGT, with no difference between the latter two. However, compared with youth with NGT, youth with IGT have significantly lower first-phase insulin and C-peptide levels and GDI (P = 0.012), whereas youth with type 2 diabetes have an additional defect in second-phase insulin. Fasting and 2-h glucose correlated with GDI (r = -0.68, P < 0.001 and r = -0.73, P < 0.001, respectively) and first-phase insulin but not with insulin sensitivity., Conclusions: Compared with youth with NGT, obese adolescents with IGT have evidence of a beta-cell defect manifested in impaired first-phase insulin secretion, with a more profound defect in type 2 diabetes involving both first- and second-phase insulin. GDI shows a significantly declining pattern: it is highest in NGT, intermediate in IGT, and lowest in type 2 diabetes. Such data suggest that measures to prevent progression or conversion from pre-diabetes to type 2 diabetes should target improvement in beta-cell function.

Functional adrenal hyperandrogenism occurs in women with polycystic ovary syndrome (PCOS). Insulin, similar to its ovarian effect, may impact the regulation of adrenal steroidogenesis by modulating the activity of P450c17alpha, the rate-limiting enzyme in androgen biosynthesis. We previously demonstrated that obese adolescents with PCOS are severely insulin resistant and are at heightened risk for impaired glucose tolerance and type 2 diabetes. In the present study we tested the hypothesis that metformin therapy in obese adolescents with PCOS will attenuate the adrenal steroidogenic response to ACTH, with reduction of insulin resistance/insulinemia. Fifteen adolescents with PCOS and impaired glucose tolerance received 3 months of metformin (850 mg, twice daily) therapy. Pre- and posttherapy they had oral glucose tolerance testing, ACTH stimulation test, a 3-h hyperinsulinemic (80 mU/m(2).min)-euglycemic clamp to assess insulin sensitivity and a hyperglycemic clamp to assess insulin secretion. After 3 months of metformin treatment, glucose intolerance improved, with eight subjects having normal glucose tolerance. Total and free T decreased [1.5 +/- 0.2 vs. 1.0 +/- 0.1 nmol/liter (P = 0.022) and 41.3 +/- 8.3 vs. 22.2 +/- 2.1 pmol/liter (P = 0.028), respectively]. Insulin-stimulated glucose disposal increased (21.5 +/- 2.2 vs. 25.0 +/- 2.2 micromol/kg.min; P = 0.041). Fasting insulin and oral glucose tolerance test insulin and glucose area under the curve decreased significantly. ACTH-stimulated increases in androstenedione, 17-hydroxyprogesterone, and 17-hydroxypregnenelone were lower after metformin treatment [2.8 +/- 0.4 vs. 1.7 +/- 0.3 nmol/liter (P = 0.014), 7.0 +/- 0.6 vs. 5.3 +/- 0.5 nmol/liter (P = 0.011), and 30.4 +/- 3.7 vs. 25.7 +/- 4.2 nmol/liter (P = 0.054)]. Fasting insulin correlated with the 17-hydroxypregnenelone response to ACTH stimulation (r = 0.52; P = 0.008). In summary, metformin treatment of obese adolescents with PCOS and impaired glucose tolerance is beneficial in improving glucose tolerance and insulin sensitivity, in lowering insulinemia, and in reducing elevated androgen levels. Moreover, metformin therapy is associated with attenuation of the adrenal steroidogenic response to ACTH. Metformin therapy was well tolerated. In conclusion, double blind, placebo-controlled studies will determine whether insulin-sensitizing therapy corrects not only ovarian hyperandrogenism but also functional adrenal hyperandrogenism in adolescents with PCOS.

The roles of insulin resistance and insulin secretion in the pathogenesis of glucose intolerance in polycystic ovary syndrome (PCOS) were evaluated in 11 adolescents with impaired glucose tolerance (IGT) and 10 with normal glucose tolerance (NGT). Hepatic glucose production and insulin-stimulated glucose disposal were measured using [6,6-(2)H(2)]glucose and a 3-h hyperinsulinemic (80 mu/m(2).min)-euglycemic clamp. First and second phase insulin secretions were evaluated during a hyperglycemic clamp. Automated blood pressure measurements were made to assess the nocturnal change in blood pressure. Hepatic glucose production was significantly higher in IGT vs. NGT. Insulin-stimulated glucose disposal was not different between the two groups. The first phase insulin level was lower in IGT (207.9 +/- 21.0 vs. 357.0 +/- 62.9 muu/mL; P = 0.025; 1247 +/- 126 vs. 2142 +/- 377 pmol/L) without a difference in second phase insulin. The glucose disposition index (product of insulin sensitivity x first phase insulin) was lower in IGT vs. NGT (278 +/- 40 vs. 567 +/- 119 mg/kg.min; P = 0.023; 1546 +/- 223 vs. 3249 +/- 663 micromol/kg.min). The glucose disposition index correlated inversely with OGTT glucose concentrations at 30, 60, and 120 min. Adolescents with PCOS-IGT lacked the normal nocturnal decline in blood pressure. We conclude that in obese adolescents with PCOS, glucose intolerance is associated with 1) decreased first phase insulin secretion, 2) decreased glucose disposition index, and 3) increased hepatic glucose production. These metabolic abnormalities are precursors of type 2 diabetes and are present early in the course of PCOS. Furthermore, the absence of nocturnal dipping in blood pressure may herald the early expression of cardiovascular disease risk in these adolescents.