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Pixner T, Chaikouskaya T, Lauth W, Zimmermann G, Mörwald K, Lischka J, Furthner D, Awender E, Geiersberger S, Maruszczak K, Forslund A, Anderwald CH, Cadamuro J, Weghuber D, Bergsten P. Rise in fasting and dynamic glucagon levels in children and adolescents with obesity is moderate in subjects with impaired fasting glucose but accentuated in subjects with impaired glucose tolerance or type 2 diabetes. Front Endocrinol (Lausanne) 2024; 15:1368570. [PMID: 39027470 PMCID: PMC11254805 DOI: 10.3389/fendo.2024.1368570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 06/14/2024] [Indexed: 07/20/2024] Open
Abstract
Background Fasting levels of glucagon are known to be elevated in youth and adults with type 2 diabetes mellitus (T2D). Children and adolescents with obesity were previously reported to show increasing fasting and post-glucose-challenge hyperglucagonemia across the spectrum of glucose tolerance, while no data are available in those with impaired fasting glucose (IFG). Materials and methods Individuals from the Beta-JUDO study population (Uppsala and Salzburg 2010-2016) (n=101, age 13.3 ± 2.8, m/f =50/51) were included (90 with overweight or obesity, 11 with normal weight). Standardized OGTT were performed and plasma glucose, glucagon and insulin concentrations assessed at baseline, 5, 10, 15, 30, 60, 90 and 120 minutes. Patients were grouped according to their glycemic state in six groups with normal glucose metabolism (NGM) and normal weight (NG-NW), NGM with obesity or overweight (NG-O), impaired glucose tolerance (IGT), impaired fasting glucose (IFG), IGT+IFG and T2D, and in two groups with NGM and impaired glucose metabolism (IGM), for statistical analysis. Results and conclusion Glucagon concentrations were elevated in young normoglycemic individuals with overweight or obesity (NG-O) compared to normoglycemic individuals with normal weight. Glucagon levels, fasting and dynamic, increased with progressing glycemic deterioration, except in IFG, where levels were comparable to those in NG-O. All glycemic groups showed an overall suppression of glucagon during OGTT. An initial increase of glucagon could be observed in T2D. In T2D, glucagon showed a strong direct linear correlation with plasma glucose levels during OGTT. Glucagon in adolescents, as in adults, may play a role in the disease progression of T2D.
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Affiliation(s)
- Thomas Pixner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Tatsiana Chaikouskaya
- Institut national supérieur des sciences agronomiques de l'alimentation et de l'environnement, Dijon, France
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Wanda Lauth
- Biostatistics and Big Medical Data, Lab for Intelligent Data Analytics (IDA) Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Georg Zimmermann
- Biostatistics and Big Medical Data, Lab for Intelligent Data Analytics (IDA) Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Katharina Mörwald
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Julia Lischka
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Dieter Furthner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Elisabeth Awender
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Sabine Geiersberger
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Clinical Research Center Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Katharina Maruszczak
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Anders Forslund
- Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
| | - Christian-Heinz Anderwald
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
- Direction, Arnoldstein Healthcare Centre, Arnoldstein, Austria
| | - Janne Cadamuro
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Daniel Weghuber
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Peter Bergsten
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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Vella M, Mohan S, Christie H, Bailey KR, Cobelli C, Dalla Man C, Matveyenko A, Egan AM, Vella A. Diabetes-associated Genetic Variation in MTNR1B and Its Effect on Islet Function. J Endocr Soc 2024; 8:bvae130. [PMID: 39011323 PMCID: PMC11249077 DOI: 10.1210/jendso/bvae130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Indexed: 07/17/2024] Open
Abstract
Context Multiple common genetic variants have been associated with type 2 diabetes, but the mechanism by which they predispose to diabetes is incompletely understood. One such example is variation in MTNR1B, which implicates melatonin and its receptor in the pathogenesis of type 2 diabetes. Objective To characterize the effect of diabetes-associated genetic variation at rs10830963 in the MTNR1B locus on islet function in people without type 2 diabetes. Design The association of genetic variation at rs10830963 with glucose, insulin, C-peptide, glucagon, and indices of insulin secretion and action were tested in a cohort of 294 individuals who had previously undergone an oral glucose tolerance test (OGTT). Insulin sensitivity, β-cell responsivity to glucose, and Disposition Indices were measured using the oral minimal model. Setting The Clinical Research and Translation Unit at Mayo Clinic, Rochester, MN. Participants Two cohorts were utilized for this analysis: 1 cohort was recruited on the basis of prior participation in a population-based study in Olmsted County. The other cohort was recruited on the basis of TCF7L2 genotype at rs7903146 from the Mayo Biobank. Intervention Two-hour, 7-sample OGTT. Main Outcome Measures Fasting, nadir, and integrated glucagon concentrations. Results One or 2 copies of the G-allele at rs10830963 were associated with increased postchallenge glucose and glucagon concentrations compared to subjects with the CC genotype. Conclusion The effects of rs10830963 on glucose homeostasis and predisposition to type 2 diabetes are likely to be partially mediated through changes in α-cell function.
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Affiliation(s)
- Max Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Sneha Mohan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Hannah Christie
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Claudio Cobelli
- Department of Women and Children's Health, University of Padova, 35128 Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, 35128 Padova, Italy
| | - Aleksey Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Aoife M Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Welch AA, Farahani RA, Egan AM, Laurenti MC, Zeini M, Vella M, Bailey KR, Cobelli C, Dalla Man C, Matveyenko A, Vella A. Glucagon-like peptide-1 receptor blockade impairs islet secretion and glucose metabolism in humans. J Clin Invest 2023; 133:e173495. [PMID: 37751301 PMCID: PMC10645389 DOI: 10.1172/jci173495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/12/2023] [Indexed: 09/27/2023] Open
Abstract
BACKGROUNDProglucagon can be processed to glucagon-like peptide1 (GLP-1) within the islet, but its contribution to islet function in humans remains unknown. We sought to understand whether pancreatic GLP-1 alters islet function in humans and whether this is affected by type 2 diabetes.METHODSWe therefore studied individuals with and without type 2 diabetes on two occasions in random order. On one occasion, exendin 9-39, a competitive antagonist of the GLP-1 Receptor (GLP1R), was infused, while on the other, saline was infused. The tracer dilution technique ([3-3H] glucose) was used to measure glucose turnover during fasting and during a hyperglycemic clamp.RESULTSExendin 9-39 increased fasting glucose concentrations; fasting islet hormone concentrations were unchanged, but inappropriate for the higher fasting glucose observed. In people with type 2 diabetes, fasting glucagon concentrations were markedly elevated and persisted despite hyperglycemia. This impaired suppression of endogenous glucose production by hyperglycemia.CONCLUSIONThese data show that GLP1R blockade impairs islet function, implying that intra-islet GLP1R activation alters islet responses to glucose and does so to a greater degree in people with type 2 diabetes.TRIAL REGISTRATIONThis study was registered at ClinicalTrials.gov NCT04466618.FUNDINGThe study was primarily funded by NIH NIDDK DK126206. AV is supported by DK78646, DK116231 and DK126206. CDM was supported by MIUR (Italian Minister for Education) under the initiative "Departments of Excellence" (Law 232/2016).
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Affiliation(s)
- Andrew A. Welch
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Rahele A. Farahani
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Aoife M. Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Marcello C. Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Maya Zeini
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Max Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Kent R. Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Aleksey Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Schembri Wismayer D, Laurenti MC, Song Y, Egan AM, Welch AA, Bailey KR, Cobelli C, Dalla Man C, Jensen MD, Vella A. Effects of acute changes in fasting glucose and free fatty acid concentrations on indices of β-cell function and glucose metabolism in subjects without diabetes. Am J Physiol Endocrinol Metab 2023; 325:E119-E131. [PMID: 37285600 PMCID: PMC10393375 DOI: 10.1152/ajpendo.00043.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/19/2023] [Accepted: 06/06/2023] [Indexed: 06/09/2023]
Abstract
Elevated fasting free fatty acids (FFAs) and fasting glucose are additively associated with impaired glucose tolerance (IGT) and decreased β-cell function [quantified as disposition index (DI)]. We sought to examine how changes in fasting FFA and glucose alter islet function. We studied 10 subjects with normal fasting glucose (NFG) and normal glucose tolerance (NGT) on two occasions. On one occasion, Intralipid and glucose were infused overnight to mimic conditions present in IFG/IGT. In addition, we studied seven subjects with IFG/IGT on two occasions. On one occasion, insulin was infused to lower overnight FFA and glucose concentrations to those observed in people with NFG/NGT. The following morning, a labeled mixed meal was used to measure postprandial glucose metabolism and β-cell function. Elevation of overnight fasting FFA and glucose in NFG/NGT did not alter peak or integrated glucose concentrations (2.0 ± 0.1 vs. 2.0 ± 0.1 Mol per 5 h, Saline vs. Intralipid/glucose, P = 0.55). Although overall β-cell function quantified by the Disposition Index was unchanged, the dynamic component of β-cell responsivity (ϕd) was decreased by Intralipid and glucose infusion (9 ± 1 vs. 16 ± 3 10-9, P = 0.02). In people with IFG/IGT, insulin did not alter postprandial glucose concentrations or indices of β-cell function. Endogenous glucose production and glucose disappearance were also unchanged in both groups. We conclude that acute, overnight changes in FFA, and glucose concentrations do not alter islet function or glucose metabolism in prediabetes.NEW & NOTEWORTHY This experiment studied the effect of changes in overnight concentrations of free fatty acids (FFAs) and glucose on β-cell function and glucose metabolism. In response to elevation of these metabolites, the dynamic component of the β-cell response to glucose was impaired. This suggests that in health overnight hyperglycemia and FFA elevation can deplete preformed insulin granules in the β-cell.
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Affiliation(s)
- Daniel Schembri Wismayer
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, United States
| | - Marcello C Laurenti
- Biomedical Engineering and Physiology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, Minnesota, United States
| | - Yilin Song
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, United States
| | - Aoife M Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, United States
| | - Andrew A Welch
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, United States
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, United States
| | - Claudio Cobelli
- Department of Woman and Child's Health, University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Michael D Jensen
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, United States
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, United States
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Farahani RA, Egan AM, Welch AA, Laurenti MC, Cobelli C, Dalla Man C, Vella A. The Effect of Glucagon-Like Peptide 1 Receptor Blockade on Glucagon-Induced Stimulation of Insulin Secretion. Diabetes 2023; 72:449-454. [PMID: 36562995 PMCID: PMC10260388 DOI: 10.2337/db22-0709] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
Data from transgenic rodent models suggest that glucagon acts as an insulin secretagogue by signaling through the glucagon-like peptide 1 receptor (GLP-1R) present on β-cells. However, its net contribution to physiologic insulin secretion in humans is unknown. To address this question, we studied individuals without diabetes in two separate experiments. Each subject was studied on two occasions in random order. In the first experiment, during a hyperglycemic clamp, glucagon was infused at 0.4 ng/kg/min, increasing by 0.2 ng/kg/min every hour for 5 h. On one day, exendin-9,39 (300 pmol/kg/min) was infused to block GLP-1R, while on the other, saline was infused. The insulin secretion rate (ISR) was calculated by nonparametric deconvolution from plasma concentrations of C-peptide. Endogenous glucose production and glucose disappearance were measured using the tracer-dilution technique. Glucagon concentrations, by design, did not differ between study days. Integrated ISR was lower during exendin-9,39 infusion (213 ± 26 vs. 191 ± 22 nmol/5 h, saline vs. exendin-9,39, respectively; P = 0.02). In the separate experiment, exendin-9,39 infusion, compared with saline infusion, also decreased the β-cell secretory response to a 1-mg glucagon bolus. These data show that, in humans without diabetes, glucagon partially stimulates the β-cell through GLP-1R.
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Affiliation(s)
- Rahele A. Farahani
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN
| | - Aoife M. Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN
| | - Andrew A. Welch
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN
| | - Marcello C. Laurenti
- Biomedical Engineering and Physiology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN
| | - Claudio Cobelli
- Department of Women’s and Children’s Health, University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN
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Kohlenberg JD, Laurenti MC, Egan AM, Wismayer DS, Bailey KR, Cobelli C, Man CD, Vella A. Differential contribution of alpha and beta cell dysfunction to impaired fasting glucose and impaired glucose tolerance. Diabetologia 2023; 66:201-212. [PMID: 36112169 PMCID: PMC9742343 DOI: 10.1007/s00125-022-05794-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/02/2022] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS People with isolated impaired fasting glucose (IFG) have normal beta cell function. We hypothesised that an increased glucose threshold for beta cell secretion explains IFG. METHODS We used graded glucose infusion to examine the relationship of insulin secretion rate (ISR) and glucagon secretion rate (GSR) with rising glucose. We studied 39 non-diabetic individuals (53 ± 2 years, BMI 30 ± 1 kg/m2), categorised by fasting glucose and glucose tolerance status. After an overnight fast, a variable insulin infusion was used to maintain glucose at ~4.44 mmol/l (07:00 to 08:30 hours). At 09:00 hours, graded glucose infusion commenced at 1 mg kg-1 min-1 and doubled every 60 min until 13:00 hours. GSR and ISR were calculated by nonparametric deconvolution from concentrations of glucagon and C-peptide, respectively. RESULTS The relationship of ISR with glucose was linear and the threshold for insulin secretion in isolated IFG did not differ from that in people with normal fasting glucose and normal glucose tolerance. GSR exhibited a single-exponential relationship with glucose that could be characterised by G50, the change in glucose necessary to suppress GSR by 50%. G50 was increased in IFG compared with normal fasting glucose regardless of the presence of impaired or normal glucose tolerance. CONCLUSIONS/INTERPRETATION These data show that, in non-diabetic humans, alpha cell dysfunction contributes to the pathogenesis of IFG independently of defects in insulin secretion. We also describe a new index that quantifies the suppression of glucagon secretion by glucose.
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Affiliation(s)
- Jacob D Kohlenberg
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Marcello C Laurenti
- Biomedical Engineering and Physiology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | - Aoife M Egan
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Daniel Schembri Wismayer
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA
| | - Claudio Cobelli
- Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA.
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Predicting Factors for Metabolic Non-Response to a Complex Lifestyle Intervention-A Replication Analysis to a Randomized-Controlled Trial. Nutrients 2022; 14:nu14224721. [PMID: 36432409 PMCID: PMC9699496 DOI: 10.3390/nu14224721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/17/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND T2DM heterogeneity affects responsiveness to lifestyle treatment. Beta-cell failure and nonalcoholic fatty liver disease (NAFLD) independently predict T2DM, but NAFLD inconsistently predicts metabolic response to lifestyle intervention. AIM We attempt to replicate a prediction model deducted from the Tübinger Lifestyle Intervention Program by assessing similar metabolic factors to predict conversion to normal glucose regulation (NGR) in a comparable lifestyle intervention trial. METHODS In the Optimal Fiber Trial (OptiFiT), 131 Caucasian participants with prediabetes completed a one-year lifestyle intervention program and received a fiber or placebo supplement. We compared baseline parameters for responders and non-responders, assessed correlations of major metabolic changes and conducted a logistic regression analysis for predictors of remission to NGR. RESULTS NGR was achieved by 33 participants, respectively. At baseline, for the placebo group only, 1 h and 2 h glucose levels, glucose AUC and Cederholm index predicted conversion to NGR. HOMA-beta, HOMA-IR or liver fat indices did not differ between responders and non-responders of the placebo or the fiber group. Changes in waist circumference or fatty liver index correlated with changes in glycemia and insulin resistance, but not with changes in insulin secretion. Insulin-resistant NAFLD did not predict non-response. Differences in compliance did not explain the results. CONCLUSIONS Higher post-challenge glucose levels strongly predicted the metabolic non-response to complex lifestyle intervention in our cohort. Depending on the specific intervention and the investigated cohort, fasting glucose levels and insulin sensitivity might contribute to the risk pattern. Beta-cell function did not improve in accordance with other metabolic improvements, qualifying as a potential risk factor for non-response. We could not replicate previous data suggesting that an insulin-resistant fatty liver is a specific risk factor for treatment failure. Replication studies are required.
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Cobelli C, Dalla Man C. Minimal and Maximal Models to Quantitate Glucose Metabolism: Tools to Measure, to Simulate and to Run in Silico Clinical Trials. J Diabetes Sci Technol 2022; 16:1270-1298. [PMID: 34032128 PMCID: PMC9445339 DOI: 10.1177/19322968211015268] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Several models have been proposed to describe the glucose system at whole-body, organ/tissue and cellular level, designed to measure non-accessible parameters (minimal models), to simulate system behavior and run in silico clinical trials (maximal models). Here, we will review the authors' work, by putting it into a concise historical background. We will discuss first the parametric portrait provided by the oral minimal models-building on the classical intravenous glucose tolerance test minimal models-to measure otherwise non-accessible key parameters like insulin sensitivity and beta-cell responsivity from a physiological oral test, the mixed meal or the oral glucose tolerance tests, and what can be gained by adding a tracer to the oral glucose dose. These models were used in various pathophysiological studies, which we will briefly review. A deeper understanding of insulin sensitivity can be gained by measuring insulin action in the skeletal muscle. This requires the use of isotopic tracers: both the classical multiple-tracer dilution and the positron emission tomography techniques are discussed, which quantitate the effect of insulin on the individual steps of glucose metabolism, that is, bidirectional transport plasma-interstitium, and phosphorylation. Finally, we will present a cellular model of insulin secretion that, using a multiscale modeling approach, highlights the relations between minimal model indices and subcellular secretory events. In terms of maximal models, we will move from a parametric to a flux portrait of the system by discussing the triple tracer meal protocol implemented with the tracer-to-tracee clamp technique. This allows to arrive at quasi-model independent measurement of glucose rate of appearance (Ra), endogenous glucose production (EGP), and glucose rate of disappearance (Rd). Both the fast absorbing simple carbs and the slow absorbing complex carbs are discussed. This rich data base has allowed us to build the UVA/Padova Type 1 diabetes and the Padova Type 2 diabetes large scale simulators. In particular, the UVA/Padova Type 1 simulator proved to be a very useful tool to safely and effectively test in silico closed-loop control algorithms for an artificial pancreas (AP). This was the first and unique simulator of the glucose system accepted by the U.S. Food and Drug Administration as a substitute to animal trials for in silico testing AP algorithms. Recent uses of the simulator have looked at glucose sensors for non-adjunctive use and new insulin molecules.
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Affiliation(s)
- Claudio Cobelli
- Department of Woman and Child’s Health University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
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Adams JD, Egan AM, Laurenti MC, Schembri Wismayer D, Bailey KR, Cobelli C, Dalla Man C, Vella A. The Effect of Diabetes-Associated Variation in TCF7L2 on Postprandial Glucose Metabolism When Glucagon and Insulin Concentrations Are Matched. Metab Syndr Relat Disord 2022; 20:329-335. [PMID: 35442800 PMCID: PMC9419949 DOI: 10.1089/met.2021.0136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background: The rs7903146 variant in the TCF7L2 gene is associated with defects in postprandial insulin and glucagon secretion and increased risk of type 2 diabetes. However, it is unclear if this variant has effects on glucose metabolism that are independent of islet function. Methods: We studied 54 nondiabetic subjects on two occasions where endogenous hormone secretion was inhibited by somatostatin. Twenty-nine subjects were homozygous for the diabetes-associated allele (TT) and 25 for the diabetes-protective allele (CC) at rs7903146, but otherwise matched for anthropometric characteristics. On 1 day, glucagon infused at a rate of 0.65 ng/kg/min, and at 0 min prevented a fall in glucagon (nonsuppressed day). On the contrary, infusion commenced at 120 min to create a transient fall in glucagon (suppressed day). Subjects received glucose (labeled with [3-3H]-glucose) infused to mimic the systemic appearance of oral glucose. Insulin was infused to mimic a prandial insulin response. Endogenous glucose production (EGP) was measured using the tracer dilution technique. Results: Lack of glucagon suppression increased postchallenge glucose concentrations and impaired EGP suppression. However, in the presence of matched insulin and glucagon concentrations, genetic variation in TCF7L2 did not alter glucose metabolism. Conclusion: These data suggest that genetic variation in TCF7L2 alters glucose metabolism through changes in islet hormone secretion.
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Affiliation(s)
- Jon D Adams
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Aoife M Egan
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Marcello C Laurenti
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Daniel Schembri Wismayer
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
| | - Claudio Cobelli
- Department of Woman and Child's Health and University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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10
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Adams JD, Egan AM, Laurenti MC, Schembri Wismayer D, Bailey KR, Cobelli C, Dalla Man C, Vella A. Insulin secretion and action and the response of endogenous glucose production to a lack of glucagon suppression in nondiabetic subjects. Am J Physiol Endocrinol Metab 2021; 321:E728-E736. [PMID: 34658253 PMCID: PMC8782666 DOI: 10.1152/ajpendo.00284.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Type 2 diabetes is a disease characterized by impaired insulin secretion and defective glucagon suppression in the postprandial period. We examined the effect of impaired glucagon suppression on glucose concentrations and endogenous glucose production (EGP) at different degrees of insulin secretory impairment. The contribution of anthropometric characteristics, peripheral, and hepatic insulin action to this variability was also examined. To do so, we studied 54 nondiabetic subjects on two occasions in which endogenous hormone secretion was inhibited by somatostatin, with glucagon infused at a rate of 0.65 ng/kg/min, at 0 min to prevent a fall in glucagon (nonsuppressed day) or at 120 min to create a transient fall in glucagon (suppressed day). Subjects received glucose (labeled with [3-3H]-glucose) infused to mimic the systemic appearance of 50-g oral glucose. Insulin was infused to mimic a prandial insulin response in 18 subjects, another 18 received 80% of the dose, and the remaining 18 received 60%. EGP was measured using the tracer-dilution technique. Decreased prandial insulin resulted in greater % increase in peak glucose but not in integrated glucose concentrations attributable to nonsuppressed glucagon. The % change in integrated EGP was unaffected by insulin dose. Multivariate regression analysis, adjusted for age, sex, weight, and insulin dose, did not show a relationship between the EGP response to impaired suppression of glucagon and insulin action as measured at the time of screening by oral glucose tolerance. A similar analysis for hepatic insulin action also did not show a relationship with the EGP response. These data indicate that the effect of impaired glucagon suppression on EGP is independent of anthropometric characteristics and insulin action.NEW & NOTEWORTHY In prediabetes, anthropometric characteristics as well as insulin action do not alter the hepatic response to glucagon. The postprandial suppression or lack of suppression of glucagon secretion is an important factor governing postprandial glucose tolerance independent of insulin secretion.
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Affiliation(s)
- Jon D Adams
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
- Department of Health and Human Performance, College of Charleston, Charleston, South Carolina
| | - Aoife M Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Marcello C Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Daniel Schembri Wismayer
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota
| | - Claudio Cobelli
- Department of Woman and Child's Health, University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
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11
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Laurenti MC, Matveyenko A, Vella A. Measurement of Pulsatile Insulin Secretion: Rationale and Methodology. Metabolites 2021; 11:409. [PMID: 34206296 PMCID: PMC8305896 DOI: 10.3390/metabo11070409] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 12/29/2022] Open
Abstract
Pancreatic β-cells are responsible for the synthesis and exocytosis of insulin in response to an increase in circulating glucose. Insulin secretion occurs in a pulsatile manner, with oscillatory pulses superimposed on a basal secretion rate. Insulin pulses are a marker of β-cell health, and secretory parameters, such as pulse amplitude, time interval and frequency distribution, are impaired in obesity, aging and type 2 diabetes. In this review, we detail the mechanisms of insulin production and β-cell synchronization that regulate pulsatile insulin secretion, and we discuss the challenges to consider when measuring fast oscillatory secretion in vivo. These include the anatomical difficulties of measuring portal vein insulin noninvasively in humans before the hormone is extracted by the liver and quickly removed from the circulation. Peripheral concentrations of insulin or C-peptide, a peptide cosecreted with insulin, can be used to estimate their secretion profile, but mathematical deconvolution is required. Parametric and nonparametric approaches to the deconvolution problem are evaluated, alongside the assumptions and trade-offs required for their application in the quantification of unknown insulin secretory rates from known peripheral concentrations. Finally, we discuss the therapeutical implication of targeting impaired pulsatile secretion and its diagnostic value as an early indicator of β-cell stress.
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Affiliation(s)
- Marcello C. Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, MN 55905, USA; (M.C.L.); (A.M.)
- Biomedical Engineering and Physiology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| | - Aleksey Matveyenko
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, MN 55905, USA; (M.C.L.); (A.M.)
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, MN 55905, USA; (M.C.L.); (A.M.)
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12
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Laurenti MC, Dalla Man C, Varghese RT, Andrews JC, Jones JG, Barosa C, Rizza RA, Matveyenko A, De Nicolao G, Bailey KR, Cobelli C, Vella A. Insulin Pulse Characteristics and Insulin Action in Non-diabetic Humans. J Clin Endocrinol Metab 2021; 106:1702-1709. [PMID: 33606017 PMCID: PMC8344841 DOI: 10.1210/clinem/dgab100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Pulsatile insulin secretion is impaired in diseases such as type 2 diabetes that are characterized by insulin resistance. This has led to the suggestion that changes in insulin pulsatility directly impair insulin signaling. We sought to examine the effects of pulse characteristics on insulin action in humans, hypothesizing that a decrease in pulse amplitude or frequency is associated with impaired hepatic insulin action. METHODS We studied 29 nondiabetic subjects on two occasions. On 1 occasion, hepatic and peripheral insulin action was measured using a euglycemic clamp. The deuterated water method was used to estimate the contribution of gluconeogenesis to endogenous glucose production. On a separate study day, we utilized nonparametric stochastic deconvolution of frequently sampled peripheral C-peptide concentrations during fasting to reconstruct portal insulin secretion. In addition to measuring basal and pulsatile insulin secretion, we used approximate entropy to measure orderliness and Fourier transform to measure the average, and the dispersion of, insulin pulse frequencies. RESULTS In univariate analysis, basal insulin secretion (R2 = 0.16) and insulin pulse amplitude (R2 = 0.09) correlated weakly with insulin-induced suppression of gluconeogenesis. However, after adjustment for age, sex, and weight, these associations were no longer significant. The other pulse characteristics also did not correlate with the ability of insulin to suppress endogenous glucose production (and gluconeogenesis) or to stimulate glucose disappearance. CONCLUSIONS Overall, our data demonstrate that insulin pulse characteristics, considered independently of other factors, do not correlate with measures of hepatic and peripheral insulin sensitivity in nondiabetic humans.
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Affiliation(s)
- Marcello C Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, MN, USA
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Ron T Varghese
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, MN, USA
| | - James C Andrews
- Vascular and Interventional Radiology, Mayo Clinic, Rochester, MN, USA
| | - John G Jones
- Center for Neurosciences, University of Coimbra, Coimbra, Portugal
| | - Cristina Barosa
- Center for Neurosciences, University of Coimbra, Coimbra, Portugal
| | - Robert A Rizza
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, MN, USA
| | - Aleksey Matveyenko
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, MN, USA
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Giuseppe De Nicolao
- Department of Computer Engineering and Systems Science, University of Pavia, Pavia, Italy
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
| | - Claudio Cobelli
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, MN, USA
- Correspondence: Adrian Vella MD, Endocrine Research Unit, Mayo Clinic College of Medicine, 200 First ST SW, 5–194 Joseph, Rochester, MN 55905, USA.
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13
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Laurenti MC, Vella A, Adams JD, Schembri Wismayer DJ, Egan AM, Dalla Man C. Assessment of individual and standardized glucagon kinetics in healthy humans. Am J Physiol Endocrinol Metab 2021; 320:E71-E77. [PMID: 33135460 PMCID: PMC8194411 DOI: 10.1152/ajpendo.00488.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Impaired glucose tolerance arises out of impaired postprandial insulin secretion and delayed suppression of glucagon. These defects occur early and independently in the pathogenesis of prediabetes. Quantification of the contribution of α-cell dysfunction to glucose tolerance has been lacking because knowledge of glucagon kinetics in humans is limited. Therefore, in a series of experiments examining the interaction of glucagon suppression with insulin secretion we studied 51 nondiabetic subjects (age = 54 ± 13 yr, BMI = 28 ± 4 kg/m2). Glucose was infused to mimic the systemic appearance of an oral challenge. Somatostatin was used to inhibit endogenous hormone secretion. 120 min after the start of the experiment, glucagon was infused at 0.65 ng/kg/min. The rise in glucagon concentrations was used to estimate its kinetic parameters [volume of distribution (Vd), half-life (t1/2), and clearance rate (CL)]. A single-exponential model provided the best fit for the data, and individualized kinetic parameters were estimated: Vd = 8.2 ± 2.7 L, t1/2 = 4 ± 1.1 min, CL = 1.4 ± 0.33 L/min. Stepwise linear regression was used to correlate Vd with BMI and sex (R2adj = 0.44), whereas CL similarly correlated with lean body mass or BSA (both R2 = 0.28). This enabled the development of a population-based model using anthropometric characteristics to predict Vd and CL. These data demonstrate that it is feasible to derive glucagon kinetic parameters from anthropometric characteristics, thereby enabling quantitation of the rate of glucagon appearance in the systemic circulation in large populations.NEW & NOTEWORTHY State-of-the-art measurement of insulin secretion in humans is accomplished by deconvolution of peripheral C-peptide concentrations using population-derived parameters of C-peptide kinetics. In contrast, knowledge of the kinetic parameters of glucagon in humans is lacking so that measurement of glucagon secretion to date is largely qualitative. This series of experiments enabled measurement of glucagon kinetics in 51 subjects, and subsequently, stepwise linear regression was used to correlate these parameters with anthropometric characteristics. This enabled the development of a population-based model using anthropometric characteristics to predict the volume of distribution and the rate of clearance. This is a necessary first step in the development of a model to quantitate of glucagon secretion and action (and its contribution to glucose tolerance) in large populations.
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Affiliation(s)
- Marcello C Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Jon D Adams
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | | | - Aoife M Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
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14
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Laurenti MC, Dalla Man C, Varghese RT, Andrews JC, Rizza RA, Matveyenko A, De Nicolao G, Cobelli C, Vella A. Diabetes-associated genetic variation in TCF7L2 alters pulsatile insulin secretion in humans. JCI Insight 2020; 5:136136. [PMID: 32182220 DOI: 10.1172/jci.insight.136136] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/05/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUNDMetabolic disorders such as type 2 diabetes have been associated with a decrease in insulin pulse frequency and amplitude. We hypothesized that the T allele at rs7903146 in TCF7L2, previously associated with β cell dysfunction, would be associated with changes in these insulin pulse characteristics.METHODSTwenty-nine nondiabetic subjects (age 46 ± 2, BMI 28 ± 1 kg/m2) participated in this study. Of these, 16 were homozygous for the C allele at rs7903146 and 13 were homozygous for the T allele. Deconvolution of peripheral C-peptide concentrations allowed the reconstruction of portal insulin secretion over time. These data were used for subsequent analyses. Pulse orderliness was assessed by approximate entropy (ApEn), and the dispersion of insulin pulses was measured by a frequency dispersion index (FDI) after a Fast Fourier Transform (FFT) of individual insulin secretion rates.RESULTSDuring fasting conditions, the CC genotype group exhibited decreased pulse disorderliness compared with the TT genotype group (1.10 ± 0.03 vs. 1.19 ± 0.04, P = 0.03). FDI decreased in response to hyperglycemia in the CC genotype group, perhaps reflecting less entrainment of insulin secretion during fasting.CONCLUSIONDiabetes-associated variation in TCF7L2 is associated with decreased orderliness and pulse dispersion, unchanged by hyperglycemia. Quantification of ApEn and FDI could represent novel markers of β cell health.FUNDINGThis work was funded by US NIH (DK78646, DK116231), University of Padova research grant CPDA145405, and Mayo Clinic General Clinical Research Center (UL1 TR000135).
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Affiliation(s)
- Marcello C Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, Minnesota, USA
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Ron T Varghese
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Robert A Rizza
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, Minnesota, USA
| | - Aleksey Matveyenko
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Giuseppe De Nicolao
- Department of Computer Engineering and Systems Science, University of Pavia, Pavia, Italy
| | - Claudio Cobelli
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, Rochester, Minnesota, USA
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15
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Visentin R, Schiavon M, Göbel B, Riz M, Cobelli C, Klabunde T, Dalla Man C. Dual glucagon-like peptide-1 receptor/glucagon receptor agonist SAR425899 improves beta-cell function in type 2 diabetes. Diabetes Obes Metab 2020; 22:640-647. [PMID: 31808298 DOI: 10.1111/dom.13939] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 12/15/2022]
Abstract
AIM To evaluate the change in insulin sensitivity, β-cell function and glucose absorption after 28 days of treatment with high and low doses of SAR425899, a novel dual glucagon-like peptide-1 receptor/glucagon receptor agonist, versus placebo. MATERIALS AND METHODS Thirty-six overweight to obese subjects with type 2 diabetes were randomized to receive daily subcutaneous administrations of low-dose SAR425899 (0.03, 0.06 and 0.09 mg) and high-dose SAR425899 (0.06, 0.12 and 0.18 mg) or placebo for 28 days; dose escalation occurred after days 7 and 14. Mixed meal tolerance tests were conducted before treatment (day -1) and on days 1 and 28. Oral glucose and C-peptide minimal models were used to quantify metabolic indices of insulin sensitivity, β-cell responsiveness and glucose absorption. RESULTS With low-dose SAR425899, high-dose SAR425899 and placebo, β-cell function from day -1 to day 28 increased by 163%, 95% and 23%, respectively. The change in area under the curve for the rate of meal glucose appearance between 0 and 120 minutes was -32%, -20% and 8%, respectively. CONCLUSIONS After 28 days of treatment, SAR425899 improved postprandial glucose control by significantly enhancing β-cell function and slowing glucose absorption rate.
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Affiliation(s)
- Roberto Visentin
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Michele Schiavon
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Britta Göbel
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - Michela Riz
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - Claudio Cobelli
- Department of Information Engineering, University of Padova, Padova, Italy
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
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16
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Mengozzi A, Tricò D, Nesti L, Petrie J, Højlund K, Mitrakou A, Krebs M, Mari A, Natali A. Disruption of fasting and post-load glucose homeostasis are largely independent and sustained by distinct and early major beta-cell function defects: a cross-sectional and longitudinal analysis of the Relationship between Insulin Sensitivity and Cardiovascular risk (RISC) study cohort. Metabolism 2020; 105:154185. [PMID: 32061908 DOI: 10.1016/j.metabol.2020.154185] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 02/10/2020] [Accepted: 02/12/2020] [Indexed: 01/26/2023]
Abstract
BACKGROUND/AIMS Uncertainty still exists on the earliest beta-cell defects at the bases of the type 2 diabetes. We assume that this depends on the inaccurate distinction between fasting and post-load glucose homeostasis and aim at providing a description of major beta-cell functions across the full physiologic spectrum of each condition. METHODS In 1320 non-diabetic individuals we performed an OGTT with insulin secretion modeling and a euglycemic insulin clamp, coupled in subgroups to glucose tracers and IVGTT; 1038 subjects underwent another OGTT after 3.5 years. Post-load glucose homeostasis was defined as mean plasma glucose above fasting levels (δOGTT). The analysis was performed by two-way ANCOVA. RESULTS Fasting plasma glucose (FPG) and δOGTT were weakly related variables (stβ = 0.12) as were their changes over time (r = -0.08). Disruption of FPG control was associated with an isolated and progressive decline (approaching 60%) of the sensitivity of the beta-cell to glucose values within the normal fasting range. Disruption of post-load glucose control was characterized by a progressive decline (approaching 60%) of the slope of the full beta-cell vs glucose dose-response curve and an early minor (30%) decline of potentiation. The acute dynamic beta-cell responses, neither per se nor in relation to the degree of insulin resistance appeared to play a relevant role in disruption of fasting or post-load homeostasis. Follow-up data qualitatively and quantitatively confirmed the results of the cross-sectional analysis. CONCLUSION In normal subjects fasting and post-load glucose homeostasis are largely independent, and their disruption is sustained by different and specific beta-cell defects.
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Affiliation(s)
- Alessandro Mengozzi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
| | - Domenico Tricò
- Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Italy
| | - Lorenzo Nesti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - John Petrie
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Kurt Højlund
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
| | - Asimina Mitrakou
- Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Alexandra Hospital, Athens, Greece
| | - Michael Krebs
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Andrea Mari
- Institute of Neuroscience, National Research Council, Padua, Italy
| | - Andrea Natali
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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17
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Adams JD, Treiber G, Hurtado MD, Laurenti MC, Dalla Man C, Cobelli C, Rizza RA, Vella A. Increased Rates of Meal Absorption Do Not Explain Elevated 1-Hour Glucose in Subjects With Normal Glucose Tolerance. J Endocr Soc 2018; 3:135-145. [PMID: 30591957 PMCID: PMC6302905 DOI: 10.1210/js.2018-00222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/16/2018] [Indexed: 01/12/2023] Open
Abstract
Context In subjects with normal fasting glucose (NFG) and normal glucose tolerance (NGT), glucose concentrations >155 mg/dL 1 hour after 75 g of oral glucose predict increased risk of progression to diabetes. Recently, it has been suggested that the mechanism underlying this abnormality is increased gut absorption of glucose. Objective We sought to determine the rate of systemic appearance of meal-derived glucose in subjects classified by their 1-hour glucose after a 75-g oral glucose challenge. Design This was a cross-sectional study. Participating subjects underwent a 75-g oral glucose challenge and a labeled mixed meal test. Setting An inpatient clinical research unit at an academic medical center. Participants Thirty-six subjects with NFG/NGT participated in this study. Interventions Subjects underwent an oral glucose tolerance test. Subsequently, they underwent a labeled mixed meal to measure fasting and postprandial glucose metabolism. Main Outcome Measures We examined β-cell function and the rate of meal appearance (Meal Ra) in NFG/NGT subjects. Subsequently, we examined the relationship of peak postchallenge glucose with Meal Ra and indices of β-cell function. Results Peak glucose concentrations correlated inversely with β-cell function. No relationship of Meal Ra with peak postchallenge glucose concentrations was observed. Conclusion In subjects with NFG/NGT, elevated 1-hour peak postchallenge glucose concentrations reflect impaired β-cell function rather than increased systemic meal appearance.
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Affiliation(s)
- J D Adams
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, Minnesota
| | - Gerlies Treiber
- Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Graz, Austria
| | - Maria Daniela Hurtado
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, Minnesota
| | - Marcello C Laurenti
- Department of Information Engineering, Università di Padova, 36131 Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, Università di Padova, 36131 Padova, Italy
| | - Claudio Cobelli
- Department of Information Engineering, Università di Padova, 36131 Padova, Italy
| | - Robert A Rizza
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, Minnesota
| | - Adrian Vella
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, Minnesota
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18
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Adams JD, Vella A. What Can Diabetes-Associated Genetic Variation in TCF7L2 Teach Us About the Pathogenesis of Type 2 Diabetes? Metab Syndr Relat Disord 2018; 16:383-389. [PMID: 29993315 DOI: 10.1089/met.2018.0024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a polygenic metabolic disorder characterized by hyperglycemia occurring as a result of impaired insulin secretion and/or insulin resistance. Among the various genetic factors associated with T2DM, a common genetic variant within the transcription factor 7-like 2 locus (TCF7L2) confers the greatest genetic risk for development of the disease. However, the mechanism(s) by which TCF7L2 predisposes to diabetes remain uncertain. Here we review the current literature pertaining to the potential mechanisms by which TCF7L2 confers risk of T2DM, using genetic variation as a probe to understand the pathogenesis of the disease.
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Affiliation(s)
- J D Adams
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine , Rochester, Minnesota
| | - Adrian Vella
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine , Rochester, Minnesota
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19
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Varghese RT, Man CD, Laurenti MC, Piccinini F, Sharma A, Shah M, Bailey KR, Rizza RA, Cobelli C, Vella A. Performance of individually measured vs population-based C-peptide kinetics to assess β-cell function in the presence and absence of acute insulin resistance. Diabetes Obes Metab 2018; 20:549-555. [PMID: 28862812 PMCID: PMC5946313 DOI: 10.1111/dom.13106] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/22/2017] [Accepted: 08/29/2017] [Indexed: 01/07/2023]
Abstract
AIMS To compare the performance of population-based kinetics with that of directly measured C-peptide kinetics when used to calculate β-cell responsivity indices, and to study people with and without acute insulin resistance to ensure that population-based kinetics apply to all conditions where β-cell function is measured. METHODS Somatostatin was used to inhibit endogenous insulin secretion in 56 people without diabetes. Subsequently, a C-peptide bolus was administered and the changing concentrations were used to calculate individual kinetic measures of C-peptide clearance. In addition, the participants were studied on 2 occasions in random order using an oral glucose tolerance test (OGTT). On one occasion, free fatty acid elevation, to cause insulin resistance, was achieved by infusion of Intralipid + heparin. The Disposition Index (DI) was then estimated by the oral minimal model using either population-based or individual C-peptide kinetics. RESULTS There were marked differences in the exchange variables (k 12 and k 21 ) of the model describing C-peptide kinetics, but smaller differences in the fractional clearance; that is, the irreversible loss from the accessible compartment (k 01 ), obtained from population-based estimates compared with experimental measurement. Because it is predominantly influenced by k 01 , DI estimated using individual kinetics correlated well with DI estimated using population-based kinetics. CONCLUSIONS These data support the use of population-based measures of C-peptide kinetics to estimate β-cell function during an OGTT.
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Affiliation(s)
- Ron T. Varghese
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, 200 1 St SW, 5-194 Joseph, Rochester, Minnesota USA
| | - Chiara Dalla Man
- Department of Information Engineering, Universita’ di Padova, Via Gradenigo 6B, Padova, Italy
| | - Marcello C. Laurenti
- Department of Information Engineering, Universita’ di Padova, Via Gradenigo 6B, Padova, Italy
| | - Francesca Piccinini
- Department of Information Engineering, Universita’ di Padova, Via Gradenigo 6B, Padova, Italy
| | - Anu Sharma
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, 200 1 St SW, 5-194 Joseph, Rochester, Minnesota USA
| | - Meera Shah
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, 200 1 St SW, 5-194 Joseph, Rochester, Minnesota USA
| | - Kent R. Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, 200 1 St SW, Rochester, Minnesota USA
| | - Robert A. Rizza
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, 200 1 St SW, 5-194 Joseph, Rochester, Minnesota USA
| | - Claudio Cobelli
- Department of Information Engineering, Universita’ di Padova, Via Gradenigo 6B, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic, 200 1 St SW, 5-194 Joseph, Rochester, Minnesota USA
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20
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Sharma A, Varghese RT, Shah M, Man CD, Cobelli C, Rizza RA, Bailey KR, Vella A. Impaired Insulin Action Is Associated With Increased Glucagon Concentrations in Nondiabetic Humans. J Clin Endocrinol Metab 2018; 103:314-319. [PMID: 29126197 PMCID: PMC5761487 DOI: 10.1210/jc.2017-01197] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 11/01/2017] [Indexed: 01/18/2023]
Abstract
Context Abnormal glucagon concentrations contribute to hyperglycemia, but the mechanisms of α-cell dysfunction in prediabetes are unclear. Objective We sought to determine the relative contributions of insulin secretion and action to α-cell dysfunction in nondiabetic participants across the spectrum of glucose tolerance. Design This was a cross-sectional study. A subset of participants (n = 120) was studied in the presence and absence of free fatty acid (FFA) elevation, achieved by infusion of Intralipid (Baxter Healthcare, Deerfield, IL) plus heparin, to cause insulin resistance. Setting An inpatient clinical research unit at an academic medical center. Participants A total of 310 nondiabetic persons participated in this study. Interventions Participants underwent a seven-sample oral glucose tolerance test. Subsequently, 120 participants were studied on two occasions. On one day, infusion of Intralipid plus heparin raised FFA. On the other day, participants received glycerol as a control. Main Outcome Measure(s) We examined the relationship of glucagon concentration with indices of insulin action after adjusting for the effects of age, sex, and weight. Subsequently, we sought to determine whether an acute decrease in insulin action, produced by FFA elevation, altered glucagon concentrations in nondiabetic participants. Results Fasting glucagon concentrations correlated positively with fasting insulin and C-peptide concentrations and inversely with insulin action. Fasting glucagon was not associated with any index of β-cell function in response to an oral challenge. As expected, FFA elevation decreased insulin action and also raised glucagon concentrations. Conclusions In nondiabetic participants, glucagon secretion was altered by changes in insulin action.
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Affiliation(s)
- Anu Sharma
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Ron T. Varghese
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Meera Shah
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Chiara Dalla Man
- Department of Information Engineering, Università di Padova, 35131 Padova, Italy
| | - Claudio Cobelli
- Department of Information Engineering, Università di Padova, 35131 Padova, Italy
| | - Robert A. Rizza
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Kent R. Bailey
- Biomedical Statistics and Informatics, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
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Sharma A, Laurenti MC, Dalla Man C, Varghese RT, Cobelli C, Rizza RA, Matveyenko A, Vella A. Glucose metabolism during rotational shift-work in healthcare workers. Diabetologia 2017; 60:1483-1490. [PMID: 28551698 PMCID: PMC5860643 DOI: 10.1007/s00125-017-4317-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 04/26/2017] [Indexed: 01/05/2023]
Abstract
AIMS/HYPOTHESIS Shift-work is associated with circadian rhythm disruption and an increased risk of obesity and type 2 diabetes. We sought to determine the effect of rotational shift-work on glucose metabolism in humans. METHODS We studied 12 otherwise healthy nurses performing rotational shift-work using a randomised crossover study design. On each occasion, participants underwent an isotope-labelled mixed meal test during a simulated day shift and a simulated night shift, enabling simultaneous measurement of glucose flux and beta cell function using the oral minimal model. We sought to determine differences in fasting and postprandial glucose metabolism during the day shift vs the night shift. RESULTS Postprandial glycaemic excursion was higher during the night shift (381±33 vs 580±48 mmol/l per 5 h, p<0.01). The time to peak insulin and C-peptide and nadir glucagon suppression in response to meal ingestion was also delayed during the night shift. While insulin action did not differ between study days, the beta cell responsivity to glucose (59±5 vs 44±4 × 10-9 min-1; p<0.001) and disposition index were decreased during the night shift. CONCLUSIONS/INTERPRETATION Impaired beta cell function during the night shift may result from normal circadian variation, the effect of rotational shift-work or a combination of both. As a consequence, higher postprandial glucose concentrations are observed during the night shift.
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Affiliation(s)
- Anu Sharma
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine, 200 First St SW, 5-194 Joseph, Rochester, MN, 55905, USA
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Ron T Varghese
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine, 200 First St SW, 5-194 Joseph, Rochester, MN, 55905, USA
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Robert A Rizza
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine, 200 First St SW, 5-194 Joseph, Rochester, MN, 55905, USA
| | - Aleksey Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Adrian Vella
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine, 200 First St SW, 5-194 Joseph, Rochester, MN, 55905, USA.
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Cobelli C, Vella A. Exocrine and Endocrine Interactions in Cystic Fibrosis: A Potential Key to Understanding Insulin Secretion in Health and Disease? Diabetes 2017; 66:20-22. [PMID: 27999103 PMCID: PMC5204318 DOI: 10.2337/dbi16-0049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Claudio Cobelli
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Metabolism, Diabetes, Nutrition, and Internal Medicine, Mayo Clinic, Rochester, MN
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Varghese RT, Dalla Man C, Sharma A, Viegas I, Barosa C, Marques C, Shah M, Miles JM, Rizza RA, Jones JG, Cobelli C, Vella A. Mechanisms Underlying the Pathogenesis of Isolated Impaired Glucose Tolerance in Humans. J Clin Endocrinol Metab 2016; 101:4816-4824. [PMID: 27603902 PMCID: PMC5155694 DOI: 10.1210/jc.2016-1998] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Prediabetes is a heterogeneous disorder classified on the basis of fasting glucose concentrations and 2-hour glucose tolerance. OBJECTIVE We sought to determine the relative contributions of insulin secretion and action to the pathogenesis of isolated impaired glucose tolerance (IGT). DESIGN The study consisted of an oral glucose tolerance test and a euglycemic clamp performed in two cohorts matched for anthropometric characteristics and fasting glucose but discordant for glucose tolerance. SETTING An inpatient clinical research unit at an academic medical center. PATIENTS OR OTHER PARTICIPANTS Twenty-five subjects who had normal fasting glucose (NFG) and normal glucose tolerance (NGT) and 19 NFG/IGT subjects participated in this study. INTERVENTION(S) Subjects underwent a seven-sample oral glucose tolerance test and a 4-hour euglycemic, hyperinsulinemic clamp on separate occasions. Glucose turnover during the clamp was measured using tracers, and endogenous hormone secretion was inhibited by somatostatin. MAIN OUTCOME MEASURES We sought to determine whether hepatic glucose metabolism, specifically the contribution of gluconeogenesis to endogenous glucose production, differed between subjects with NFG/NGT and those with NFG/IGT. RESULTS Endogenous glucose production did not differ between groups before or during the clamp. Insulin-stimulated glucose disappearance was lower in NFG/IGT (24.6 ± 2.2 vs 35.0 ± 3.6 μmol/kg/min; P = .03). The disposition index was decreased in NFG/IGT (681 ± 102 vs 2231 ± 413 × 10-14 dL/kg/min2 per pmol/L; P < .001). CONCLUSIONS We conclude that innate defects in the regulation of glycogenolysis and gluconeogenesis do not contribute to NFG/IGT. However, insulin-stimulated glucose disposal is impaired, exacerbating defects in β-cell function.
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Affiliation(s)
- Ron T Varghese
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Chiara Dalla Man
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Anu Sharma
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Ivan Viegas
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Cristina Barosa
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Catia Marques
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Meera Shah
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - John M Miles
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Robert A Rizza
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - John G Jones
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Claudio Cobelli
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
| | - Adrian Vella
- Division of Endocrinology, Diabetes, and Metabolism (R.T.V., A.S., M.S., J.M.M., R.A.R., A.V.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Information Engineering (C.D.M., C.C.), Universitá di Padova, 35122 Padova, Italy; Center for Neurosciences and Cell Biology (I.V., C.B., C.M., J.G.J.), University of Coimbra, 3000-370 Coimbra, Portugal; and APDP-Portuguese Diabetes Association (J.G.J.), 1250-203 Lisbon, Portugal
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Shankar SS, Vella A, Raymond RH, Staten MA, Calle RA, Bergman RN, Cao C, Chen D, Cobelli C, Dalla Man C, Deeg M, Dong JQ, Lee DS, Polidori D, Robertson RP, Ruetten H, Stefanovski D, Vassileva MT, Weir GC, Fryburg DA. Standardized Mixed-Meal Tolerance and Arginine Stimulation Tests Provide Reproducible and Complementary Measures of β-Cell Function: Results From the Foundation for the National Institutes of Health Biomarkers Consortium Investigative Series. Diabetes Care 2016; 39:1602-13. [PMID: 27407117 PMCID: PMC5001146 DOI: 10.2337/dc15-0931] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/15/2016] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Standardized, reproducible, and feasible quantification of β-cell function (BCF) is necessary for the evaluation of interventions to improve insulin secretion and important for comparison across studies. We therefore characterized the responses to, and reproducibility of, standardized methods of in vivo BCF across different glucose tolerance states. RESEARCH DESIGN AND METHODS Participants classified as having normal glucose tolerance (NGT; n = 23), prediabetes (PDM; n = 17), and type 2 diabetes mellitus (T2DM; n = 22) underwent two standardized mixed-meal tolerance tests (MMTT) and two standardized arginine stimulation tests (AST) in a test-retest paradigm and one frequently sampled intravenous glucose tolerance test (FSIGT). RESULTS From the MMTT, insulin secretion in T2DM was >86% lower compared with NGT or PDM (P < 0.001). Insulin sensitivity (Si) decreased from NGT to PDM (∼50%) to T2DM (93% lower [P < 0.001]). In the AST, insulin secretory response to arginine at basal glucose and during hyperglycemia was lower in T2DM compared with NGT and PDM (>58%; all P < 0.001). FSIGT showed decreases in both insulin secretion and Si across populations (P < 0.001), although Si did not differ significantly between PDM and T2DM populations. Reproducibility was generally good for the MMTT, with intraclass correlation coefficients (ICCs) ranging from ∼0.3 to ∼0.8 depending on population and variable. Reproducibility for the AST was very good, with ICC values >0.8 across all variables and populations. CONCLUSIONS Standardized MMTT and AST provide reproducible and complementary measures of BCF with characteristics favorable for longitudinal interventional trials use.
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Affiliation(s)
- Sudha S Shankar
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN
| | | | - Myrlene A Staten
- Kelly Government Solutions for National Institute of Diabetes and Digestive and Kidney Diseases, Rockville, MD
| | | | - Richard N Bergman
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA
| | - Charlie Cao
- Takeda Development Center Americas, Deerfield, IL
| | | | - Claudio Cobelli
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Mark Deeg
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | | | | | | | - R Paul Robertson
- Pacific Northwest Diabetes Research Institute, Seattle, WA Division of Endocrinology, Departments of Medicine and Pharmacology, University of Washington, Seattle, WA
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Shah M, Varghese RT, Miles JM, Piccinini F, Dalla Man C, Cobelli C, Bailey KR, Rizza RA, Vella A. TCF7L2 Genotype and α-Cell Function in Humans Without Diabetes. Diabetes 2016; 65:371-80. [PMID: 26525881 PMCID: PMC4747457 DOI: 10.2337/db15-1233] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/26/2015] [Indexed: 12/20/2022]
Abstract
The diabetes-associated allele in TCF7L2 increases the rate of conversion to diabetes; however, the mechanism by which this occurs remains elusive. We hypothesized that the diabetes-associated allele in this locus (rs7903146) impairs insulin secretion and that this defect would be exacerbated by acute free fatty acid (FFA)-induced insulin resistance. We studied 120 individuals of whom one-half were homozygous for the diabetes-associated allele TT at rs7903146 and one-half were homozygous for the protective allele CC. After a screening examination during which glucose tolerance status was determined, subjects were studied on two occasions in random order while undergoing an oral challenge. During one study day, FFA was elevated by infusion of Intralipid plus heparin. On the other study day, subjects received the same amount of glycerol as present in the Intralipid infusion. β-Cell responsivity indices were estimated with the oral C-peptide minimal model. We report that β-cell responsivity was slightly impaired in the TT genotype group. Moreover, the hyperbolic relationship between insulin secretion and β-cell responsivity differed significantly between genotypes. Subjects also exhibited impaired suppression of glucagon after an oral challenge. These data imply that a genetic variant harbored within the TCF7L2 locus impairs glucose tolerance through effects on glucagon as well as on insulin secretion.
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Affiliation(s)
- Meera Shah
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition Research, Mayo Clinic, Rochester, MN
| | - Ron T Varghese
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition Research, Mayo Clinic, Rochester, MN
| | - John M Miles
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition Research, Mayo Clinic, Rochester, MN
| | - Francesca Piccinini
- Department of Information Engineering, Università degli Studi di Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, Università degli Studi di Padova, Padova, Italy
| | - Claudio Cobelli
- Department of Information Engineering, Università degli Studi di Padova, Padova, Italy
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN
| | - Robert A Rizza
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition Research, Mayo Clinic, Rochester, MN
| | - Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition Research, Mayo Clinic, Rochester, MN
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Vella A, Cobelli C. Defective Glucagon-Like Peptide 1 Secretion in Prediabetes and Type 2 Diabetes Is Influenced by Weight and Sex. Chicken, Egg, or None of the Above? Diabetes 2015; 64:2324-5. [PMID: 26106191 PMCID: PMC4876752 DOI: 10.2337/db15-0292] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
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Javed A, Balagopal PB, Vella A, Fischer PR, Piccinini F, Dalla Man C, Cobelli C, Giesler PD, Laugen JM, Kumar S. Association between thyrotropin levels and insulin sensitivity in euthyroid obese adolescents. Thyroid 2015; 25:478-84. [PMID: 25777801 PMCID: PMC4426325 DOI: 10.1089/thy.2015.0005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Thyrotropin (TSH) levels display a positive association with body mass index (BMI), and the prevalence of isolated hyperthyrotropinemia is higher in obese adolescents compared to their normal weight controls. However, the metabolic significance of the higher TSH in obese adolescents is less clear. The objective of this study was to determine the relationship between TSH concentrations and insulin sensitivity, lipids, and adipokines in euthyroid, non-diabetic, obese adolescents. METHODS Thirty-six euthyroid, non-diabetic, obese adolescents between the ages of 12 and 18 years underwent a 75 g oral glucose tolerance test. Insulin sensitivity (Si) and pancreatic β-cell function as assessed by disposition index (DI) were measured using the oral glucose minimal model approach. Cholesterol (total, low-density lipoprotein [LDL-C], and high-density lipoprotein [HDL-C]), triglycerides (TG), interleukin-6 (IL-6), total and high molecular weight (HMW) adiponectin, and retinol binding protein-4 (RBP4) were also determined. Associations between measures of thyroid function and Si, DI, lipids, and adipokines were computed using Pearson's correlation coefficient and multiple regression analysis. RESULTS The mean age of the subjects was 14.3±1.88 years, and the mean BMI was 32.5±4.65 kg/m2; 97% were non-Hispanic white and 47% were male. The mean TSH was 2.7±1.2 mIU/L. Increasing serum TSH was correlated with decreasing Si (log Si) in the entire cohort (p=0.03), but this relationship persisted only in males (p=0.02). The correlation between TSH and Si in males remained significant after adjusting for BMI (p=0.02). There was no correlation between TSH and pancreatic β-cell function as assessed by DI (p=0.48). TSH correlated positively with LDL-C (p=0.04) and IL-6 (p=0.03), but these associations vanished or weakened after adjusting for BMI (LDL-C p-value=0.44; IL-6 p-value=0.07). CONCLUSIONS This study suggests a sex-specific association between TSH and insulin sensitivity in euthyroid, non-diabetic, obese adolescent males. Prospective studies are warranted to explore further this sexual dimorphism in the relationship between thyroid function and insulin sensitivity and to determine if obese adolescents with insulin resistance receiving thyroid supplements for hypothyroidism would benefit from targeting TSH levels in the lower half of normal range.
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Affiliation(s)
- Asma Javed
- Division of Pediatric Endocrinology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
| | | | - Adrian Vella
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Philip R. Fischer
- Division of General Pediatric and Adolescent Medicine, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Paula D. Giesler
- Endocrine Research Unit, Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Jeanette M. Laugen
- Endocrine Research Unit, Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Seema Kumar
- Division of Pediatric Endocrinology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
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Vella A. β-cell function after weight-loss induced by bariatric surgery. Physiology (Bethesda) 2014; 29:84-5. [PMID: 24583763 DOI: 10.1152/physiol.00003.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Abstract
The simultaneous assessment of insulin action, secretion, and hepatic extraction is key to understanding postprandial glucose metabolism in nondiabetic and diabetic humans. We review the oral minimal method (i.e., models that allow the estimation of insulin sensitivity, β-cell responsivity, and hepatic insulin extraction from a mixed-meal or an oral glucose tolerance test). Both of these oral tests are more physiologic and simpler to administer than those based on an intravenous test (e.g., a glucose clamp or an intravenous glucose tolerance test). The focus of this review is on indices provided by physiological-based models and their validation against the glucose clamp technique. We discuss first the oral minimal model method rationale, data, and protocols. Then we present the three minimal models and the indices they provide. The disposition index paradigm, a widely used β-cell function metric, is revisited in the context of individual versus population modeling. Adding a glucose tracer to the oral dose significantly enhances the assessment of insulin action by segregating insulin sensitivity into its glucose disposal and hepatic components. The oral minimal model method, by quantitatively portraying the complex relationships between the major players of glucose metabolism, is able to provide novel insights regarding the regulation of postprandial metabolism.
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Affiliation(s)
- Claudio Cobelli
- Department of Information Engineering, University of Padova, Padova, Italy
- Corresponding author: Claudio Cobelli,
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Gianna Toffolo
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Rita Basu
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN
| | - Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN
| | - Robert Rizza
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN
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Sathananthan M, Farrugia LP, Miles JM, Piccinini F, Dalla Man C, Zinsmeister AR, Cobelli C, Rizza RA, Vella A. Direct effects of exendin-(9,39) and GLP-1-(9,36)amide on insulin action, β-cell function, and glucose metabolism in nondiabetic subjects. Diabetes 2013; 62:2752-6. [PMID: 23545708 PMCID: PMC3717878 DOI: 10.2337/db13-0140] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exendin-(9,39) is a competitive antagonist of glucagon-like peptide-1 (GLP-1) at its receptor. However, it is unclear if it has direct and unique effects of its own. We tested the hypothesis that exendin-(9,39) and GLP-1-(9,36)amide have direct effects on hormone secretion and β-cell function as well as glucose metabolism in healthy subjects. Glucose containing [3-(3)H]glucose was infused to mimic the systemic appearance of glucose after a meal. Saline, GLP-1-(9,36)amide, or exendin-(9,39) at 30 pmol/kg/min (Ex 30) or 300 pmol/kg/min (Ex 300) were infused in random order on separate days. Integrated glucose concentrations were slightly but significantly increased by exendin-(9,39) (365 ± 43 vs. 383 ± 35 vs. 492 ± 49 vs. 337 ± 50 mmol per 6 h, saline, Ex 30, Ex 300, and GLP-1-[9,36]amide, respectively; P = 0.05). Insulin secretion did not differ among groups. However, insulin action was lowered by exendin-(9,39) (25 ± 4 vs. 20 ± 4 vs. 18 ± 3 vs. 21 ± 4 10(-4) dL/kg[min per μU/mL]; P = 0.02), resulting in a lower disposition index (DI) during exendin-(9,39) infusion (1,118 ± 118 vs. 816 ± 83 vs. 725 ± 127 vs. 955 ± 166 10(-14) dL/kg/min(2) per pmol/L; P = 0.003). Endogenous glucose production and glucose disappearance did not differ significantly among groups. We conclude that exendin-(9,39), but not GLP-1-(9,36)amide, decreases insulin action and DI in healthy humans.
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Affiliation(s)
- Matheni Sathananthan
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Luca P. Farrugia
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - John M. Miles
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Alan R. Zinsmeister
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Robert A. Rizza
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
- Corresponding author: Adrian Vella,
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Abstract
Uncarboxylated osteocalcin enhances insulin and adiponectin release and improves glucose tolerance in mice. Data in humans do not unequivocally support a role for osteocalcin in glucose homeostasis. Changes in the amount of uncarboxylated osteocalcin induced by vitamin K or warfarin treatment are not associated with changes in glucose and insulin concentrations. Interventional studies in humans, designed to detect small changes in insulin secretion and action attributable to changes in uncarboxylated osteocalcin, will be required to reliably detect effects of osteocalcin on glucose metabolism and to better understand its interaction with adiposity and adipokines.
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Smushkin G, Sathananthan M, Sathananthan A, Dalla Man C, Micheletto F, Zinsmeister AR, Cobelli C, Vella A. Diabetes-associated common genetic variation and its association with GLP-1 concentrations and response to exogenous GLP-1. Diabetes 2012; 61:1082-9. [PMID: 22461567 PMCID: PMC3331759 DOI: 10.2337/db11-1732] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 02/16/2012] [Indexed: 12/12/2022]
Abstract
The mechanisms by which common genetic variation predisposes to type 2 diabetes remain unclear. The disease-associated variants in TCF7L2 (rs7903146) and WFS1 (rs10010131) have been shown to affect response to exogenous glucagon-like peptide 1 (GLP-1), while variants in KCNQ1 (rs151290, rs2237892, and rs2237895) alter endogenous GLP-1 secretion. We set out to validate these observations using a model of GLP-1-induced insulin secretion. We studied healthy individuals using a hyperglycemic clamp and GLP-1 infusion. In addition, we measured active and total GLP-1 in response to an oral challenge in nondiabetic subjects. After genotyping the relevant single nucleotide polymorphisms, generalized linear regression models and repeated-measures ANCOVA models incorporating potential confounders, such as age and BMI, were used to assess the associations, if any, of response with genotype. These variants did not alter GLP-1 concentrations in response to oral intake. No effects on β-cell responsiveness to hyperglycemia and GLP-1 infusion were apparent. Diabetes-associated variation (T allele at rs7903146) in TCF7L2 may impair the ability of hyperglycemia to suppress glucagon (45 ± 2 vs. 47 ± 2 vs. 60 ± 5 ng/L for CC, CT, and TT, respectively, P = 0.02). In nondiabetic subjects, diabetes-associated genetic variation does not alter GLP-1 concentrations after an oral challenge or its effect on insulin secretion.
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Affiliation(s)
- Galina Smushkin
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Matheni Sathananthan
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Airani Sathananthan
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | | | - Alan R. Zinsmeister
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
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Affiliation(s)
- Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota, USA.
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