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Shapiro ALB, Tjaden AH, Edelstein SL, Kahn SE, Srikanthan P, Knowler WC, Venditti EM, Golden SH, Carmichael O, Luchsinger JA. The association of insulin responses and insulin sensitivity with cognition in adults with pre-diabetes: The Diabetes Prevention Program Outcomes Study. J Diabetes Complications 2024; 38:108764. [PMID: 38701667 DOI: 10.1016/j.jdiacomp.2024.108764] [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: 02/14/2024] [Revised: 04/06/2024] [Accepted: 04/29/2024] [Indexed: 05/05/2024]
Abstract
OBJECTIVE Dysglycemia is a significant risk factor for cognitive impairment. However, which pathophysiologic determinant(s) of dysglycemia, impaired insulin sensitivity (ISens) or the islet β-cell's response (IResp), contribute to poorer cognitive function, independent of dysglycemia is not established. Among 1052 adults with pre-diabetes from the Diabetes Prevention Program Outcomes Study (DPPOS), we investigated the relationship between IResp, ISens and cognitive function. RESEARCH DESIGN AND METHODS IResp was estimated by the insulinogenic index (IGI; pmol/mmol) and ISens as 1/fasting insulin from repeated annual oral glucose tolerance tests. The mean IResp and mean ISens were calculated over approximately 12 years of follow-up. Verbal learning (Spanish-English Verbal Learning Test [SEVLT]) and executive function (Digital Symbol Substitution Test [DSST]) were assessed at the end of the follow-up period. Linear regression models were run for each cognitive outcome and were adjusted for dysglycemia and other factors. RESULTS Higher IResp was associated with poorer performance on the DSST (-0.69 points per 100 unit increase in IGI, 95 % CI: -1.37, -0.01). ISens was not associated with DSST, nor were IResp or ISens associated with performance on the SEVLT. CONCLUSIONS These results suggest that a greater β-cell response in people at high risk for type 2 diabetes is associated with poorer executive function, independent of dysglycemia and ISens.
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Affiliation(s)
- Allison L B Shapiro
- Lifecourse Epidemiology of Adiposity and Diabetes (LEAD) Center, University of Colorado at Anschutz (CU-Anschutz), USA; Section of Endocrinology, Department of Pediatrics, School of Medicine, CU-Anschutz, USA.
| | - Ashley H Tjaden
- Biostatistics Center, Milken Institute School of Public Health, George Washington University, Rockville, MD, USA
| | - Sharon L Edelstein
- Biostatistics Center, Milken Institute School of Public Health, George Washington University, Rockville, MD, USA
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA, USA
| | - Preethi Srikanthan
- Division of Endocrinology, UCLA Health System, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - William C Knowler
- Consultant: Biostatistics Center, Milken Institute School of Public Health, George Washington University, Rockville, MD, USA
| | | | - Sherita H Golden
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - José A Luchsinger
- Departments of Medicine and Epidemiology, Columbia University Irving Medical Center, New York, NY, USA
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Weingarten MFJ, Scholz M, Wohland T, Horn K, Stumvoll M, Kovacs P, Tönjes A. Circulating Oxytocin Is Genetically Determined and Associated With Obesity and Impaired Glucose Tolerance. J Clin Endocrinol Metab 2019; 104:5621-5632. [PMID: 31361301 DOI: 10.1210/jc.2019-00643] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 07/22/2019] [Indexed: 01/01/2023]
Abstract
CONTEXT Despite the emerging evidence on the role of oxytocin (OXT) in metabolic diseases, there is a lack of well-powered studies addressing the relationship of circulating OXT with obesity and diabetes. OBJECTIVES AND DESIGN Here, we measured OXT in a study cohort (n = 721; 396 women, 325 men; mean age ± SD, 47.7 ± 15.2 years) with subphenotypes related to obesity, including anthropometric traits such as body mass index [BMI (mean ± SD), 26.8 ± 4.6 kg/m2], waist-to-hip ratio (WHR; 0.88 ± 0.09), blood parameters (glucose, 5.32 ± 0.50 mmol/L; insulin, 5.3 ± 3.3 µU/mL), and oral glucose tolerance test to clarify the association with OXT. We also tested in a genome-wide association study (GWAS) whether the interindividual variation in OXT serum levels might be explained by genetic variation. RESULTS The OXT concentration was increased in subjects with elevated BMI and positively correlated with WHR, waist circumference, and triglyceride levels. The OXT concentration in subjects with BMI <25 kg/m2 was significantly lower (n = 256; 78.6 pg/mL) than in subjects with a BMI between 25 and 30 kg/m2 (n = 314; 98.5 pg/mL, P = 6 × 10-6) and with BMI >30 kg/m2 (n = 137; 106.4 pg/mL, P = 8 × 10-6). OXT levels were also positively correlated with plasma glucose and insulin and were elevated in subjects with impaired glucose tolerance (P = 4.6 × 10-3). Heritability of OXT was estimated at 12.8%. In a GWAS, two hits in linkage disequilibrium close (19 kb) to the OXT reached genome-wide significant association (top-hit rs12625893, P = 3.1 × 10-8, explained variance 3%). CONCLUSIONS Our data show that OXT is genetically affected by a variant near OXT and is associated with obesity and impaired glucose tolerance.
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Affiliation(s)
| | - Markus Scholz
- Institute for Medical Informatics, Statistics, and Epidemiology, University of Leipzig, Leipzig, Germany
- LIFE Research Center, University of Leipzig, Leipzig, Germany
| | - Tobias Wohland
- IFB Adiposity Diseases, University of Leipzig Medical Center, Leipzig, Germany
| | - Katrin Horn
- Institute for Medical Informatics, Statistics, and Epidemiology, University of Leipzig, Leipzig, Germany
- LIFE Research Center, University of Leipzig, Leipzig, Germany
| | - Michael Stumvoll
- Medical Department III-Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Peter Kovacs
- Medical Department III-Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
- IFB Adiposity Diseases, University of Leipzig Medical Center, Leipzig, Germany
| | - Anke Tönjes
- Medical Department III-Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
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Beta-cell function is associated with carotid intima-media thickness independently of insulin resistance in healthy individuals. J Hypertens 2016; 34:685-91. [DOI: 10.1097/hjh.0000000000000842] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hivert MF, Christophi CA, Franks PW, Jablonski KA, Ehrmann DA, Kahn SE, Horton ES, Pollin TI, Mather KJ, Perreault L, Barrett-Connor E, Knowler WC, Florez JC. Lifestyle and Metformin Ameliorate Insulin Sensitivity Independently of the Genetic Burden of Established Insulin Resistance Variants in Diabetes Prevention Program Participants. Diabetes 2016; 65:520-6. [PMID: 26525880 PMCID: PMC4747453 DOI: 10.2337/db15-0950] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/27/2015] [Indexed: 12/15/2022]
Abstract
Large genome-wide association studies of glycemic traits have identified genetics variants that are associated with insulin resistance (IR) in the general population. It is unknown whether people with genetic enrichment for these IR variants respond differently to interventions that aim to improve insulin sensitivity. We built a genetic risk score (GRS) based on 17 established IR variants and effect sizes (weighted IR-GRS) in 2,713 participants of the Diabetes Prevention Program (DPP) with genetic consent. We tested associations between the weighted IR-GRS and insulin sensitivity index (ISI) at baseline in all participants, and with change in ISI over 1 year of follow-up in the DPP intervention (metformin and lifestyle) and control (placebo) arms. All models were adjusted for age, sex, ethnicity, and waist circumference at baseline (plus baseline ISI for 1-year ISI change models). A higher IR-GRS was associated with lower baseline ISI (β = -0.754 [SE = 0.229] log-ISI per unit, P = 0.001 in fully adjusted models). There was no differential effect of treatment for the association between the IR-GRS on the change in ISI; higher IR-GRS was associated with an attenuation in ISI improvement over 1 year (β = -0.520 [SE = 0.233], P = 0.03 in fully adjusted models; all treatment arms). Lifestyle intervention and metformin treatment improved the ISI, regardless of the genetic burden of IR variants.
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Affiliation(s)
- Marie-France Hivert
- Department of Population Medicine, Harvard Pilgrim Health Care Institute, Harvard Medical School, Boston, MA Diabetes Research Center (Diabetes Unit), Department of Medicine, Massachusetts General Hospital, Boston, MA Department of Medicine, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | | | - Paul W Franks
- Genetic & Molecular Epidemiology Unit, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö, Sweden Department of Nutrition, Harvard School of Public Health, Boston, MA Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden
| | | | - David A Ehrmann
- Department of Medicine, The University of Chicago School of Medicine, Chicago, IL
| | - Steven E Kahn
- Division of Metabolism, Endocrinology & Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, WA
| | - Edward S Horton
- Section on Clinical, Behavioral & Outcomes Research, Joslin Diabetes Center, Boston, MA Department of Medicine, Harvard Medical School, Boston, MA
| | - Toni I Pollin
- Departments of Medicine and Epidemiology & Public Health, University of Maryland School of Medicine, Baltimore, MD Program in Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD
| | - Kieren J Mather
- Division of Endocrinology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Leigh Perreault
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Elizabeth Barrett-Connor
- Division of Epidemiology, Department of Family Medicine and Public Health, University of California, San Diego, La Jolla, CA
| | - William C Knowler
- Diabetes Epidemiology and Clinical Research Section, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
| | - Jose C Florez
- Diabetes Research Center (Diabetes Unit), Department of Medicine, Massachusetts General Hospital, Boston, MA Department of Medicine, Harvard Medical School, Boston, MA Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA Program in Medical and Population Genetics, Broad Institute, Cambridge, MA
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Hamman RF, Horton E, Barrett-Connor E, Bray GA, Christophi CA, Crandall J, Florez JC, Fowler S, Goldberg R, Kahn SE, Knowler WC, Lachin JM, Murphy MB, Venditti E. Factors affecting the decline in incidence of diabetes in the Diabetes Prevention Program Outcomes Study (DPPOS). Diabetes 2015; 64:989-98. [PMID: 25277389 PMCID: PMC4338587 DOI: 10.2337/db14-0333] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 09/21/2014] [Indexed: 12/21/2022]
Abstract
During the first 7 years of the Diabetes Prevention Program Outcomes Study (DPPOS), diabetes incidence rates, when compared with the Diabetes Prevention Program (DPP), decreased in the placebo (-42%) and metformin (-25%), groups compared with the rates in the intensive lifestyle intervention (+31%) group. Participants in the placebo and metformin groups were offered group intensive lifestyle intervention prior to entering the DPPOS. The following two hypotheses were explored to explain the rate differences: "effective intervention" (changes in weight and other factors due to intensive lifestyle intervention) and "exhaustion of susceptible" (changes in mean genetic and diabetes risk scores). No combination of behavioral risk factors (weight, physical activity, diet, smoking, and antidepressant or statin use) explained the lower DPPOS rates of diabetes progression in the placebo and metformin groups, whereas weight gain was the factor associated with higher rates of progression in the intensive lifestyle intervention group. Different patterns in the average genetic risk score over time were consistent with exhaustion of susceptibles. Results were consistent with exhaustion of susceptibles for the change in incidence rates, but not the availability of intensive lifestyle intervention to all persons before the beginning of the DPPOS. Thus, effective intervention did not explain the lower diabetes rates in the DPPOS among subjects in the placebo and metformin groups compared with those in the DPP.
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Affiliation(s)
- Richard F Hamman
- Department of Epidemiology, Colorado School of Public Health, University of Colorado at Denver, Aurora, CO
| | - Edward Horton
- Section on Clinical Research, Joslin Diabetes Center, Boston, MA
| | | | - George A Bray
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA
| | | | | | | | - Sarah Fowler
- Biostatistics Center, George Washington University, Rockville, MD
| | - Ronald Goldberg
- Diabetes Research Institute, University of Miami School of Medicine, Miami, FL
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA
| | - William C Knowler
- National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
| | - John M Lachin
- Biostatistics Center, George Washington University, Rockville, MD
| | - Mary Beth Murphy
- Division of Endocrinology, University of Tennessee Health Science Center, Memphis, TN
| | - Elizabeth Venditti
- Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center Health Systems, Pittsburgh, PA
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Nutrients utilization in obese individuals with and without hypertriglyceridemia. Nutrients 2014; 6:790-8. [PMID: 24566437 PMCID: PMC3942732 DOI: 10.3390/nu6020790] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/23/2014] [Accepted: 02/12/2014] [Indexed: 11/24/2022] Open
Abstract
Background: Low fat utilization is linked to weight gain and to the presence of certain atherosclerosis markers. It is not clear whether the presence of hyperlipidemia can further affect nutrients utilization. The main objective of this study was to investigate the fasting fuel utilization of obese subjects suffering from hypertriglyceridemia, and to compare it with that of individuals that are solely obese. Method: We recruited 20 obese individuals with hypertriglyceridemia and 20 matched individuals not affected by hypertriglyceridemia. The fuel utilization (respiratory quotient) was measured by respiratory gas exchange, by Indirect Calorimetry. Results: There was a significant difference in fuel utilization and HDL-cholesterol between cases and controls (respiratory quotient 0.89 ± 0.07 vs. 0.84 ± 0.06; p = 0.020 respectively). The univariate and multivariate linear regression analysis confirmed that hypertrygliceridemia was positively correlated to the respiratory quotient (p = 0.035). Conclusion: obese subjects with hypertriglyceridemia had a higher respiratory quotient in comparison to unaffected subjects. This could suggest a limitation in the beta-oxidation mechanisms; this could actually imply that fatty acids may be redirected from oxidation to reesterification into triglycerides. The study could suggest the presence of different mechanisms unrelated to obesity and also a potential new therapeutic target for hypertriglyceridemia management.
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Fat depots, free fatty acids, and dyslipidemia. Nutrients 2013; 5:498-508. [PMID: 23434905 PMCID: PMC3635208 DOI: 10.3390/nu5020498] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 01/31/2013] [Accepted: 02/04/2013] [Indexed: 11/29/2022] Open
Abstract
Body fat deposition and excess free fatty acid (FFA) metabolism contribute to dyslipidemia and the adverse health consequences of obesity. Individuals with upper body obesity have impaired functioning of adipocytes, the primary fatty acid storage site. Excess visceral fat is strongly associated with impaired suppression of FFA release in response to insulin, as well as with hypertriglyceridemia and low concentrations of high density lipoprotein (HDL) cholesterol. High FFA concentrations can induce insulin resistance in muscle and liver. Furthermore, failure of hyperinsulinemia to normally suppress FFA is associated with impaired carbohydrate oxidation and muscle glucose storage, reduced hepatic insulin clearance and elevated triglycerides. Understanding the impact of body fat distribution on FFA metabolism and dyslipidemia is critical for determining the link between overweight and obesity and cardiovascular disease risk. In the current review, we will explore the relationship between adipose tissue, body fat depots, and FFA metabolism.
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Bush NC, Basu R, Rizza RA, Nair KS, Khosla S, Jensen MD. Insulin-mediated FFA suppression is associated with triglyceridemia and insulin sensitivity independent of adiposity. J Clin Endocrinol Metab 2012; 97:4130-8. [PMID: 22933539 PMCID: PMC3485612 DOI: 10.1210/jc.2012-2285] [Citation(s) in RCA: 19] [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: 12/30/2022]
Abstract
CONTEXT A central/visceral fat distribution and excess free fatty acid (FFA) availability are associated with dyslipidemia and insulin resistance. However, these two characteristics often coexist, making it difficult to detect the independent contributions of each. Whether FFA suppression is more closely linked to metabolic abnormalities is not clear. OBJECTIVE The aim of the study was to examine the relationship between FFA suppression, body fat distribution, and fitness as contributors toward insulin resistance and hypertriglyceridemia. DESIGN We measured systemic palmitate turnover using an iv infusion of [9,10-(3)H]palmitate; upper body sc adipose tissue (UBSQ) and visceral adipose tissue (VAT) with dual-energy x-ray absorptiometry and a single-slice abdominal computed tomography scan; fitness with a graded exercise treadmill test; and insulin sensitivity with both the iv glucose tolerance test (IVGTT) (SI(IVGTT)) and mixed meal tolerance test (SI(Meal)). SETTING The study was conducted at a General Clinical Research Center. PARTICIPANTS Baseline data were obtained from 140 elderly adults (age, 60-88 yr; 83 males) and 60 young adults (age, 18-31 yr; 31 males) who participated in a previously published trial assessing the effects of 2-yr supplementation of dehydroepiandrosterone or testosterone on body composition, glucose metabolism, and bone density. INTERVENTIONS There were no interventions. MAIN OUTCOME MEASURES We measured fasting plasma triglyceride (TG) concentrations, SI(IVGTT), and SI(Meal). RESULTS Using multivariate regression analysis, the strongest combined predictors of TG concentrations were VAT, postmeal nadir FFA concentrations, sex, and age. The best predictors of SI(IVGTT) were IVGTT nadir palmitate concentration, VAT, UBSQ fat, fitness, and age, whereas the best predictors of SI(Meal) were meal nadir palmitate concentration, UBSQ fat, fitness, and sex. CONCLUSIONS FFA suppression is associated with both fasting TG concentrations and insulin sensitivity, independent of measures of adiposity.
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Affiliation(s)
- Nikki C Bush
- Mayo Clinic, Endocrine Research Unit, 200 First Street SW, Room 5-194 Joseph, Rochester, Minnesota 55905, USA
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9
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Salgin B, Ong KK, Thankamony A, Emmett P, Wareham NJ, Dunger DB. Higher fasting plasma free fatty acid levels are associated with lower insulin secretion in children and adults and a higher incidence of type 2 diabetes. J Clin Endocrinol Metab 2012; 97:3302-9. [PMID: 22740706 DOI: 10.1210/jc.2012-1428] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CONTEXT There are limited data in humans on the association between fasting free fatty acid (FFA) levels and pancreatic β-cell function. OBJECTIVE Our objective was to examine this association in children and adults with normal glucose tolerance and to explore fasting FFA levels in relation to subsequent risk of impaired glucose tolerance (IGT) and type 2 diabetes (T2D). DESIGN We measured FFA, glucose, and insulin levels after an overnight fast and 30 min after an oral glucose load in 797 children aged 8 yr in the Avon Longitudinal Study of Parents and Children and 770 adults aged 44-71 yr in the Medical Research Council Ely Study. We calculated the homeostasis model assessment to estimate fasting insulin sensitivity, the insulinogenic index to estimate insulin secretion, and the disposition index to assess insulin secretion corrected for insulin sensitivity. RESULTS Higher fasting FFA levels were associated with lower insulin secretion in children (boys, P = 0.03; girls, P = 0.001) and adults (men, P = 0.03, women, P = 0.04). Associations with insulin sensitivity were more variable, but after adjustment for insulin sensitivity, higher fasting FFA levels remained associated with lower insulin secretion (disposition index). Compared with adults in the lowest tertile of fasting FFA levels, those in the middle and highest tertiles had a 3-fold higher incidence of IGT or T2D over the following 5-8 yr. CONCLUSIONS Higher fasting FFA levels were consistently associated with lower insulin secretion in children and adults with normal glucose tolerance. Furthermore, higher fasting FFA levels were prospectively associated with a greater risk of subsequent IGT and T2D.
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Affiliation(s)
- Burak Salgin
- University Department of Paediatrics, University of Cambridge, Cambridge CB2 0QQ, United Kingdom.
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Byrne CD. Dorothy Hodgkin Lecture 2012: non-alcoholic fatty liver disease, insulin resistance and ectopic fat: a new problem in diabetes management. Diabet Med 2012; 29:1098-107. [PMID: 22672330 DOI: 10.1111/j.1464-5491.2012.03732.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Non-alcoholic fatty liver disease is now recognized as the hepatic component of the metabolic syndrome. Non-alcoholic fatty liver disease is a spectrum of fat-associated liver conditions that can result in end-stage liver disease and the need for liver transplantation. Simple steatosis, or fatty liver, occurs early in non-alcoholic fatty liver disease and may progress to non-alcoholic steatohepatitis, fibrosis and cirrhosis with increased risk of hepatocellular carcinoma. Prevalence estimates for non-alcoholic fatty liver disease range from 17 to 33% in the general populations and it has been estimated that non-alcoholic fatty liver disease exists in up to 70% of people with Type 2 diabetes. Non-alcoholic fatty liver disease increases risk of Type 2 diabetes and cardiovascular disease. In people with Type 2 diabetes, non-alcoholic fatty liver disease is the most frequent cause (∼80%) of fatty liver diagnosed by ultrasound. As non-alcoholic fatty liver disease is strongly associated with insulin resistance, the presence of non-alcoholic fatty liver disease with diabetes often contributes to poor glycaemic control. Consequently, strategies that decrease liver fat and improve whole-body insulin sensitivity may both contribute to prevention of Type 2 diabetes and to better glycaemic control in people who already have developed diabetes. This review summarizes the Dorothy Hodgkin lecture given by the author at the 2012 Diabetes UK annual scientific conference, proposing that fatty acid fluxes through the liver are crucial for the pathogenesis of non-alcoholic fatty liver disease and for increasing insulin resistance.
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Affiliation(s)
- C D Byrne
- Nutrition and Metabolism and NIHR Southampton Biomedical Research Centre, University Hospital Southampton and Faculty of Medicine, University of Southampton, Southampton, UK.
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Hivert MF, Jablonski KA, Perreault L, Saxena R, McAteer JB, Franks PW, Hamman RF, Kahn SE, Haffner S, Meigs JB, Altshuler D, Knowler WC, Florez JC. Updated genetic score based on 34 confirmed type 2 diabetes Loci is associated with diabetes incidence and regression to normoglycemia in the diabetes prevention program. Diabetes 2011; 60:1340-8. [PMID: 21378175 PMCID: PMC3064108 DOI: 10.2337/db10-1119] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Over 30 loci have been associated with risk of type 2 diabetes at genome-wide statistical significance. Genetic risk scores (GRSs) developed from these loci predict diabetes in the general population. We tested if a GRS based on an updated list of 34 type 2 diabetes-associated loci predicted progression to diabetes or regression toward normal glucose regulation (NGR) in the Diabetes Prevention Program (DPP). RESEARCH DESIGN AND METHODS We genotyped 34 type 2 diabetes-associated variants in 2,843 DPP participants at high risk of type 2 diabetes from five ethnic groups representative of the U.S. population, who had been randomized to placebo, metformin, or lifestyle intervention. We built a GRS by weighting each risk allele by its reported effect size on type 2 diabetes risk and summing these values. We tested its ability to predict diabetes incidence or regression to NGR in models adjusted for age, sex, ethnicity, waist circumference, and treatment assignment. RESULTS In multivariate-adjusted models, the GRS was significantly associated with increased risk of progression to diabetes (hazard ratio [HR] = 1.02 per risk allele [95% CI 1.00-1.05]; P = 0.03) and a lower probability of regression to NGR (HR = 0.95 per risk allele [95% CI 0.93-0.98]; P < 0.0001). At baseline, a higher GRS was associated with a lower insulinogenic index (P < 0.001), confirming an impairment in β-cell function. We detected no significant interaction between GRS and treatment, but the lifestyle intervention was effective in the highest quartile of GRS (P < 0.0001). CONCLUSIONS A high GRS is associated with increased risk of developing diabetes and lower probability of returning to NGR in high-risk individuals, but a lifestyle intervention attenuates this risk.
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Affiliation(s)
- Marie-France Hivert
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | | | - Leigh Perreault
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado at Denver School of Medicine, Aurora, Colorado
| | - Richa Saxena
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute, Cambridge, Massachusetts
| | - Jarred B. McAteer
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute, Cambridge, Massachusetts
| | - Paul W. Franks
- Department of Public Health and Clinical Medicine, Division of Medicine, Genetic Epidemiology and Clinical Research Group, Umeå University Hospital, Umeå, Sweden
- Department of Clinical Sciences, Lund University Diabetes Center, Lund University, Malmö, Sweden
| | - Richard F. Hamman
- Department of Epidemiology, Colorado School of Public Health, University of Colorado at Denver, Aurora, Colorado
| | - Steven E. Kahn
- Division of Metabolism, Endocrinology and Nutrition, Veterans’ Affairs Puget Sound Health Care System and the University of Washington, Seattle, Washington
| | | | | | - James B. Meigs
- General Medicine Unit, Massachusetts General Hospital, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - David Altshuler
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute, Cambridge, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
- Diabetes Research Center (Diabetes Unit), Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - William C. Knowler
- Diabetes Epidemiology and Clinical Research Section, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona
| | - Jose C. Florez
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute, Cambridge, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
- Diabetes Research Center (Diabetes Unit), Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Corresponding author: Jose C. Florez, and
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Lemieux S, Bédard A, Piché MÈ, Weisnagel SJ, Corneau L, Bergeron J. Visceral adipose tissue accumulation and cardiovascular disease risk profile in postmenopausal women with impaired glucose tolerance or type 2 diabetes. Clin Endocrinol (Oxf) 2011; 74:340-5. [PMID: 21092050 DOI: 10.1111/j.1365-2265.2010.03933.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Women with impaired glucose tolerance (IGT) and type 2 diabetes (T2D) are more at risk of cardiovascular disease. The aim of this study was to test the hypothesis that increased visceral adipose tissue (VAT) could explain to a large extent alterations in the cardiovascular disease risk profile of postmenopausal women with IGT or T2D. DESIGN, PATIENTS AND MEASUREMENTS Sixty-two women with normal glucose tolerance (NGT), 33 with IGT and 18 with de novo diagnosed T2D were tested. The sample was further divided into five groups: (i) NGT-low VAT (<130 cm(2) ); (ii) NGT-high VAT (≥130 cm(2)); (iii) IGT-low VAT (<130 cm(2) ); (iv) IGT-high VAT (≥130 cm(2) ) and (v) T2D. RESULTS Women with T2D, women with IGT-high VAT and those with NGT-high VAT all had lower insulin sensitivity as determined by the euglycaemic-hyperinsulinaemic clamp (M_I), higher triglyceride (TG), lower HDL(2)-cholesterol (chol) levels and higher levels of high-sensitivity C-reactive protein than women with NGT-low VAT. Only differences in M_I and early insulin response (EIR) were observed between women with IGT-high VAT and those with NGT-high VAT (lower values in IGT-high VAT). Women with T2D had lower M_I and EIR as well as higher plasma TG and lower plasma Apo A1 and HDL-chol concentrations than women with NGT-high VAT. CONCLUSIONS Our results suggest that increase in VAT accumulation usually found in women with IGT explains to a large extent the deterioration in their plasma lipid-lipoprotein and inflammatory profile. However, factors other than VAT are involved in explaining the high TG-low HDL dyslipidaemia observed in women with T2D.
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Affiliation(s)
- Simone Lemieux
- Institute of Nutraceuticals and Functional Foods, Laval University, Québec, Québec, Canada.
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Bailey WA, Westman EC, Marquart ML, Guyton JR. Low glycemic diet for weight loss in hypertriglyceridemic patients attending a lipid clinic. J Clin Lipidol 2010; 4:508-14. [PMID: 21122698 DOI: 10.1016/j.jacl.2010.08.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 08/18/2010] [Accepted: 08/18/2010] [Indexed: 11/18/2022]
Abstract
PURPOSE To assess the effectiveness of low glycemic dietary counseling for weight loss among moderately hypertriglyceridemic patients in an academic referral lipid clinic. METHODS During 1998 to 2000, weight loss advice followed traditional guidelines. Beginning in 2001, hypertriglyceridemic patients were advised to greatly reduce intake of high glycemic carbohydrates. The clinic database was queried for all patients initiating consultative treatment from 1998 through 2004. Subjects were included if initial fasting triglyceride was 200 to 800 mg/dL and if at least two follow-up visits were made during a period of 365 days or more. Mean percent changes from baseline in weight and lipid/lipoproteins beyond 1 year were calculated. Macronutrient composition was determined 3- to 5-day food diaries submitted by subjects from the highest quartile of weight loss. RESULTS Patients (n = 56) first seen in 1998-2000 had 0.2 ± 0.7% mean weight gain beyond one year compared with 3.0 ± 0.5% weight loss for patients (n = 141) initially seen in 2001 to 2004 (P < .001 comparing groups). Weight loss correlated with triglyceride reduction (-2.6 mg/dL per kilogram body weight, r = 0.29, P < .001) and with HDL-C increase (0.22 mg/dL per kilogram body weight, r = 0.16; P = .038). Highest quartile weight losers in the low glycemic group (n = 15) reported consuming 44% carbohydrate calories, 32% fat, 22% protein, and 2% alcohol. CONCLUSION Hypertriglyceridemic patients who received low glycemic dietary counseling and maintained clinic attendance more than 1 year achieved mean 3.0% weight loss. This was improved compared with historical controls with traditional dietary counseling. Food diaries from successful weight losers suggested compliance with a low glycemic, moderately reduced carbohydrate diet plan.
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Richards JC, Johnson TK, Kuzma JN, Lonac MC, Schweder MM, Voyles WF, Bell C. Short-term sprint interval training increases insulin sensitivity in healthy adults but does not affect the thermogenic response to beta-adrenergic stimulation. J Physiol 2010. [PMID: 20547683 DOI: 10.1113/jphysiol.2010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Sprint interval training (SIT) and traditional endurance training elicit similar physiological adaptations. From the perspective of metabolic function, superior glucose regulation is a common characteristic of endurance-trained adults. Accordingly, we have investigated the hypothesis that short-term SIT will increase insulin sensitivity in sedentary/recreationally active humans. Thirty one healthy adults were randomly assigned to one of three conditions: (1) SIT (n = 12): six sessions of repeated (4-7) 30 s bouts of very high-intensity cycle ergometer exercise over 14 days; (2) sedentary control (n = 10); (3) single-bout SIT (n = 9): one session of 4 x 30 s cycle ergometer sprints. Insulin sensitivity was determined (hyperinsulinaemic euglycaemic clamp) prior to and 72 h following each intervention. Compared with baseline, and sedentary and single-bout controls, SIT increased insulin sensitivity (glucose infusion rate: 6.3 +/- 0.6 vs. 8.0 +/- 0.8 mg kg(1) min(1); mean +/- s.e.m.; P = 0.04). In a separate study, we investigated the effect of SIT on the thermogenic response to beta-adrenergic receptor (beta-AR) stimulation, an important determinant of energy balance. Compared with baseline, and sedentary and single-bout control groups, SIT did not affect resting energy expenditure (EE: ventilated hood technique; 6274 +/- 226 vs. 6079 +/- 297 kJ day(1); P = 0.51) or the thermogenic response to isoproterenol (6, 12 and 24 ng (kg fat-free mass)(1) min(1): %EE 11 +/- 2, 14 +/- 3, 23 +/- 2 vs. 11 +/- 1, 16 +/- 2, 25 +/- 3; P = 0.79). Combined data from both studies revealed no effect of SIT on fasted circulating concentrations of glucose, insulin, adiponectin, pigment epithelial-derived factor, non-esterified fatty acids or noradrenaline (all P > 0.05). Sixteen minutes of high-intensity exercise over 14 days augments insulin sensitivity but does not affect the thermogenic response to beta-AR stimulation.
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Affiliation(s)
- Jennifer C Richards
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523-1582, USA
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Richards JC, Johnson TK, Kuzma JN, Lonac MC, Schweder MM, Voyles WF, Bell C. Short-term sprint interval training increases insulin sensitivity in healthy adults but does not affect the thermogenic response to beta-adrenergic stimulation. J Physiol 2010; 588:2961-72. [PMID: 20547683 DOI: 10.1113/jphysiol.2010.189886] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sprint interval training (SIT) and traditional endurance training elicit similar physiological adaptations. From the perspective of metabolic function, superior glucose regulation is a common characteristic of endurance-trained adults. Accordingly, we have investigated the hypothesis that short-term SIT will increase insulin sensitivity in sedentary/recreationally active humans. Thirty one healthy adults were randomly assigned to one of three conditions: (1) SIT (n = 12): six sessions of repeated (4-7) 30 s bouts of very high-intensity cycle ergometer exercise over 14 days; (2) sedentary control (n = 10); (3) single-bout SIT (n = 9): one session of 4 x 30 s cycle ergometer sprints. Insulin sensitivity was determined (hyperinsulinaemic euglycaemic clamp) prior to and 72 h following each intervention. Compared with baseline, and sedentary and single-bout controls, SIT increased insulin sensitivity (glucose infusion rate: 6.3 +/- 0.6 vs. 8.0 +/- 0.8 mg kg(1) min(1); mean +/- s.e.m.; P = 0.04). In a separate study, we investigated the effect of SIT on the thermogenic response to beta-adrenergic receptor (beta-AR) stimulation, an important determinant of energy balance. Compared with baseline, and sedentary and single-bout control groups, SIT did not affect resting energy expenditure (EE: ventilated hood technique; 6274 +/- 226 vs. 6079 +/- 297 kJ day(1); P = 0.51) or the thermogenic response to isoproterenol (6, 12 and 24 ng (kg fat-free mass)(1) min(1): %EE 11 +/- 2, 14 +/- 3, 23 +/- 2 vs. 11 +/- 1, 16 +/- 2, 25 +/- 3; P = 0.79). Combined data from both studies revealed no effect of SIT on fasted circulating concentrations of glucose, insulin, adiponectin, pigment epithelial-derived factor, non-esterified fatty acids or noradrenaline (all P > 0.05). Sixteen minutes of high-intensity exercise over 14 days augments insulin sensitivity but does not affect the thermogenic response to beta-AR stimulation.
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Affiliation(s)
- Jennifer C Richards
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523-1582, USA
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Ingelsson E, Langenberg C, Hivert MF, Prokopenko I, Lyssenko V, Dupuis J, Mägi R, Sharp S, Jackson AU, Assimes TL, Shrader P, Knowles JW, Zethelius B, Abbasi FA, Bergman RN, Bergmann A, Berne C, Boehnke M, Bonnycastle LL, Bornstein SR, Buchanan TA, Bumpstead SJ, Böttcher Y, Chines P, Collins FS, Cooper CC, Dennison EM, Erdos MR, Ferrannini E, Fox CS, Graessler J, Hao K, Isomaa B, Jameson KA, Kovacs P, Kuusisto J, Laakso M, Ladenvall C, Mohlke KL, Morken MA, Narisu N, Nathan DM, Pascoe L, Payne F, Petrie JR, Sayer AA, Schwarz PEH, Scott LJ, Stringham HM, Stumvoll M, Swift AJ, Syvänen AC, Tuomi T, Tuomilehto J, Tönjes A, Valle TT, Williams GH, Lind L, Barroso I, Quertermous T, Walker M, Wareham NJ, Meigs JB, McCarthy MI, Groop L, Watanabe RM, Florez JC. Detailed physiologic characterization reveals diverse mechanisms for novel genetic Loci regulating glucose and insulin metabolism in humans. Diabetes 2010; 59:1266-75. [PMID: 20185807 PMCID: PMC2857908 DOI: 10.2337/db09-1568] [Citation(s) in RCA: 194] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Recent genome-wide association studies have revealed loci associated with glucose and insulin-related traits. We aimed to characterize 19 such loci using detailed measures of insulin processing, secretion, and sensitivity to help elucidate their role in regulation of glucose control, insulin secretion and/or action. RESEARCH DESIGN AND METHODS We investigated associations of loci identified by the Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC) with circulating proinsulin, measures of insulin secretion and sensitivity from oral glucose tolerance tests (OGTTs), euglycemic clamps, insulin suppression tests, or frequently sampled intravenous glucose tolerance tests in nondiabetic humans (n = 29,084). RESULTS The glucose-raising allele in MADD was associated with abnormal insulin processing (a dramatic effect on higher proinsulin levels, but no association with insulinogenic index) at extremely persuasive levels of statistical significance (P = 2.1 x 10(-71)). Defects in insulin processing and insulin secretion were seen in glucose-raising allele carriers at TCF7L2, SCL30A8, GIPR, and C2CD4B. Abnormalities in early insulin secretion were suggested in glucose-raising allele carriers at MTNR1B, GCK, FADS1, DGKB, and PROX1 (lower insulinogenic index; no association with proinsulin or insulin sensitivity). Two loci previously associated with fasting insulin (GCKR and IGF1) were associated with OGTT-derived insulin sensitivity indices in a consistent direction. CONCLUSIONS Genetic loci identified through their effect on hyperglycemia and/or hyperinsulinemia demonstrate considerable heterogeneity in associations with measures of insulin processing, secretion, and sensitivity. Our findings emphasize the importance of detailed physiological characterization of such loci for improved understanding of pathways associated with alterations in glucose homeostasis and eventually type 2 diabetes.
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Affiliation(s)
- Erik Ingelsson
- Corresponding authors: Erik Ingelsson, ; Leif Groop, ; Richard M. Watanabe, ; Jose C. Florez,
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Leif Groop
- Corresponding authors: Erik Ingelsson, ; Leif Groop, ; Richard M. Watanabe, ; Jose C. Florez,
| | - Richard M. Watanabe
- Corresponding authors: Erik Ingelsson, ; Leif Groop, ; Richard M. Watanabe, ; Jose C. Florez,
| | - Jose C. Florez
- Corresponding authors: Erik Ingelsson, ; Leif Groop, ; Richard M. Watanabe, ; Jose C. Florez,
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Ramachandran A, Snehalatha C, Mary S, Selvam S, Kumar CKS, Seeli AC, Shetty AS. Pioglitazone does not enhance the effectiveness of lifestyle modification in preventing conversion of impaired glucose tolerance to diabetes in Asian Indians: results of the Indian Diabetes Prevention Programme-2 (IDPP-2). Diabetologia 2009; 52:1019-26. [PMID: 19277602 DOI: 10.1007/s00125-009-1315-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 02/09/2009] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS The objective of this prevention programme was to study whether combining pioglitazone with lifestyle modification would enhance the efficacy of lifestyle modification in preventing type 2 diabetes in Asian Indians with impaired glucose tolerance. METHODS In a community-based, placebo-controlled 3 year prospective study, 407 participants with impaired glucose tolerance (mean age 45.3 +/- 6.2 years, mean BMI 25.9 +/- 3.3 kg/m(2)) were sequentially grouped to receive either: lifestyle modification plus pioglitazone, 30 mg (n = 204) or lifestyle modification plus placebo (n = 203). The participants and investigators were blinded to the assignment. The primary outcome was development of diabetes. RESULTS At baseline, both groups had similar demographic, anthropometric and biochemical characteristics. At year 3, the response rate was 90.2%. The cumulative incidence of diabetes was 29.8% with pioglitazone and 31.6% with placebo (unadjusted HR 1.084 [95% CI 0.753-1.560], p = 0.665). Normoglycaemia was achieved in 40.9% and 32.3% of participants receiving pioglitazone and placebo, respectively (p = 0.109). In pioglitazone group, two deaths and two non-fatal hospitalisations occurred due to cardiac problems; in the placebo group there were two occurrences of cardiac disease. CONCLUSIONS/INTERPRETATION Despite good adherence to lifestyle modification and drug therapy, no additional effect of pioglitazone was seen above that achieved with placebo. The effectiveness of the intervention in both groups was comparable with that of lifestyle modification alone, as reported from the Indian Diabetes Prevention Programme-1. The results are at variance with studies that showed significant relative risk reduction in conversion to diabetes with pioglitazone in Americans with IGT. An ethnicity-related difference in the action of pioglitazone in non-diabetic participants may be one explanation. TRIAL REGISTRATION ClinicalTrials.gov NCT00276497 FUNDING: This study was funded by the India Diabetes Research Foundation.
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Affiliation(s)
- A Ramachandran
- India Diabetes Research Foundation, Egmore, Chennai, India.
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Moore AF, Jablonski KA, Mason CC, McAteer JB, Arakaki RF, Goldstein BJ, Kahn SE, Kitabchi AE, Hanson RL, Knowler WC, Florez JC. The association of ENPP1 K121Q with diabetes incidence is abolished by lifestyle modification in the diabetes prevention program. J Clin Endocrinol Metab 2009; 94:449-55. [PMID: 19017751 PMCID: PMC2646511 DOI: 10.1210/jc.2008-1583] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Insulin resistance is an important feature of type 2 diabetes. Ectoenzyme nucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) inhibits insulin signaling, and a recent meta-analysis reported a nominal association between the Q allele in the K121Q (rs1044498) single nucleotide polymorphism in its gene ENPP1 and type 2 diabetes. OBJECTIVE AND INTERVENTION: We examined the impact of this polymorphism on diabetes incidence as well as insulin secretion and sensitivity at baseline and after treatment with a lifestyle intervention or metformin vs. placebo in the Diabetes Prevention Program (DPP). DESIGN, SETTING, PARTICIPANTS, AND OUTCOME: We genotyped ENPP1 K121Q in 3548 DPP participants and performed Cox regression analyses using genotype, intervention, and interactions as predictors of diabetes incidence. RESULTS Fasting glucose and glycated hemoglobin were higher in QQ homozygotes at baseline (P < 0.001 for both). There was a significant interaction between genotype at rs1044498 and intervention under the dominant model (P = 0.03). In analyses stratified by treatment arm, a positive association with diabetes incidence was found in Q allele carriers compared to KK homozygotes [hazard ratio (HR), 1.38; 95% confidence interval (CI), 1.08-1.76; P = 0.009] in the placebo arm (n = 996). Lifestyle modification eliminated this increased risk. These findings persisted after adjustment for body mass index and race/ethnicity. Association of ENPP1 K121Q genotype with diabetes incidence under the additive and recessive genetic models showed consistent trends [HR, 1.10 (95% CI, 0.99-1.23), P = 0.08; and HR, 1.16 (95% CI, 0.92-1.45), P = 0.20, respectively] but did not reach statistical significance. CONCLUSIONS ENPP1 K121Q is associated with increased diabetes incidence; the DPP lifestyle intervention eliminates this increased risk.
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Affiliation(s)
- Allan F Moore
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts 02114-2622, USA
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Moore AF, Jablonski KA, McAteer JB, Saxena R, Pollin TI, Franks PW, Hanson RL, Shuldiner AR, Knowler WC, Altshuler D, Florez JC. Extension of type 2 diabetes genome-wide association scan results in the diabetes prevention program. Diabetes 2008; 57:2503-10. [PMID: 18544707 PMCID: PMC2518503 DOI: 10.2337/db08-0284] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 06/01/2008] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Genome-wide association scans (GWASs) have identified novel diabetes-associated genes. We evaluated how these variants impact diabetes incidence, quantitative glycemic traits, and response to preventive interventions in 3,548 subjects at high risk of type 2 diabetes enrolled in the Diabetes Prevention Program (DPP), which examined the effects of lifestyle intervention, metformin, and troglitazone versus placebo. RESEARCH DESIGN AND METHODS We genotyped selected single nucleotide polymorphisms (SNPs) in or near diabetes-associated loci, including EXT2, CDKAL1, CDKN2A/B, IGF2BP2, HHEX, LOC387761, and SLC30A8 in DPP participants and performed Cox regression analyses using genotype, intervention, and their interactions as predictors of diabetes incidence. We evaluated their effect on insulin resistance and secretion at 1 year. RESULTS None of the selected SNPs were associated with increased diabetes incidence in this population. After adjustments for ethnicity, baseline insulin secretion was lower in subjects with the risk genotype at HHEX rs1111875 (P = 0.01); there were no significant differences in baseline insulin sensitivity. Both at baseline and at 1 year, subjects with the risk genotype at LOC387761 had paradoxically increased insulin secretion; adjustment for self-reported ethnicity abolished these differences. In ethnicity-adjusted analyses, we noted a nominal differential improvement in beta-cell function for carriers of the protective genotype at CDKN2A/B after 1 year of troglitazone treatment (P = 0.01) and possibly lifestyle modification (P = 0.05). CONCLUSIONS We were unable to replicate the GWAS findings regarding diabetes risk in the DPP. We did observe genotype associations with differences in baseline insulin secretion at the HHEX locus and a possible pharmacogenetic interaction at CDKNA2/B.
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Affiliation(s)
- Allan F. Moore
- Center for Human Genetic Research, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Diabetes Center, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
| | | | - Jarred B. McAteer
- Center for Human Genetic Research, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Richa Saxena
- Center for Human Genetic Research, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Toni I. Pollin
- Department of Medicine, Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, Maryland
| | - Paul W. Franks
- Genetic Epidemiology and Clinical Research Group, Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University Hospital, Umeå, Sweden
| | - Robert L. Hanson
- Diabetes Epidemiology and Clinical Research Section, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona
| | - Alan R. Shuldiner
- Department of Medicine, Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, Maryland
| | - William C. Knowler
- Diabetes Epidemiology and Clinical Research Section, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona
| | - David Altshuler
- Center for Human Genetic Research, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Diabetes Center, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Jose C. Florez
- Center for Human Genetic Research, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Diabetes Center, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
- Program in Medical and Population Genetics, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
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Martínez-López E, Ruíz-Madrigal B, Hernández-Cañaveral I, Panduro A. Association of the T54 allele of the FABP2 gene with cardiovascular risk factors in obese Mexican subjects. Diab Vasc Dis Res 2007; 4:235-6. [PMID: 17907115 DOI: 10.3132/dvdr.2007.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Genetic predisposition to cardiovascular risk may vary between different ethnic groups. We studied the effect of the FABP2 A54T polymorphism on biochemical and anthropometric cardiovascular risk factors in 114 obese Mexican subjects. The mean age of the patients studied was 36.8+/-13.3 years. Insulin resistance was present in 47%, hypercholesterolaemia in 49% and hypertriglyceridaemia in 45%. Frequency of the FABP2 genotype was 39% AA, 54.8% AT and 6.2% TT. The AT/TT group showed an increase in body mass index (34+/-7.1 vs. 31+/-4.8 kg/m2), waist circumference (101+/-15.7 vs. 96.5+/-15.8 cm), triglycerides (145+/-60.8 vs. 127+/-79.4 mg/dL; 1.64+/-0.67 vs. 1.43+/-0.89 mmol/L), total cholesterol (176+/-39.4 vs. 164+/-38.2 mg/dL; 4.55+/-1.02 vs. 4.24+/-0.99 mmol/L), LDL (121+/-24.2 vs. 111+/-25.9 mg/dL; 3.13+/-0.62 vs. 2.88+/-0.67 mmol/L) and VLDL (28.8+/-12.1 vs. 25.1+/-16.1 mg/dL; 0.74+/-0.31 vs. 0.64+/-0.41 mmol/L) compared to the AA group (p<0.05). The AT/TT group had greatly increased cardiovascular risk, with an OR of 7.56 (95% CI, 1.82-36.24; p<0.001) compared to the AA group. Our results suggest that A54T polymorphism of the FABP2 gene is associated with cardiovascular disease risk in obese subjects.
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Affiliation(s)
- Erika Martínez-López
- Service of Molecular Biology in Medicine, Civil Hospital of Guadalajara Fray Antonio Alcalde, PO Box 2-500, Guadalajara, Jalisco, Mexico 44280
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Florez JC, Sjögren M, Agapakis CM, Burtt NP, Almgren P, Lindblad U, Berglund G, Tuomi T, Gaudet D, Daly MJ, Ardlie KG, Hirschhorn JN, Altshuler D, Groop L. Association testing of common variants in the insulin receptor substrate-1 gene (IRS1) with type 2 diabetes. Diabetologia 2007; 50:1209-17. [PMID: 17443311 DOI: 10.1007/s00125-007-0657-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Accepted: 02/08/2007] [Indexed: 10/23/2022]
Abstract
AIMS/HYPOTHESIS Activation of the insulin receptor substrate-1 (IRS1) is a key initial step in the insulin signalling pathway. Despite several reports of association of the G972R polymorphism in its gene IRS1 with type 2 diabetes, we and others have not observed this association in well-powered samples. However, other nearby variants might account for the putative association signal. SUBJECTS AND METHODS We characterised the haplotype map of IRS1 and selected 20 markers designed to capture common variations in the region. We genotyped this comprehensive set of markers in several family-based and case-control samples of European descent totalling 12,129 subjects. RESULTS In an initial sample of 2,235 North American and Polish case-control pairs, the minor allele of the rs934167 polymorphism showed nominal evidence of association with type 2 diabetes (odds ratio [OR] 1.25, 95% CI 1.03-1.51, p = 0.03). This association showed a trend in the same direction in 7,659 Scandinavian samples (OR 1.16, 95% CI 0.96-1.39, p = 0.059). The combined OR was 1.20 (p = 0.008), but statistical correction for the number of variants examined yielded a p value of 0.086. We detected no differences across rs934167 genotypes in insulin-related quantitative traits. CONCLUSIONS/INTERPRETATION Our data do not support an association of common variants in IRS1 with type 2 diabetes in populations of European descent.
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Affiliation(s)
- J C Florez
- Simches Research Building-CPZN 6820, Diabetes Unit/Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA.
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Florez JC, Jablonski KA, Sun MW, Bayley N, Kahn SE, Shamoon H, Hamman RF, Knowler WC, Nathan DM, Altshuler D. Effects of the type 2 diabetes-associated PPARG P12A polymorphism on progression to diabetes and response to troglitazone. J Clin Endocrinol Metab 2007; 92:1502-9. [PMID: 17213274 PMCID: PMC2267936 DOI: 10.1210/jc.2006-2275] [Citation(s) in RCA: 110] [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] [Indexed: 11/19/2022]
Abstract
CONTEXT The common P12A polymorphism in PPARG (a target for thiazolidinedione medications) has been consistently associated with type 2 diabetes. OBJECTIVE We examined whether PPARG P12A affects progression from impaired glucose tolerance to diabetes, or responses to preventive interventions (lifestyle, metformin, or troglitazone vs. placebo). PATIENTS This study included 3548 Diabetes Prevention Program participants. DESIGN We performed Cox regression analysis using genotype at PPARG P12A, intervention, and their interactions as predictors of diabetes incidence. We also genotyped five other PPARG variants implicated in the response to troglitazone and assessed their effect on insulin sensitivity at 1 yr. RESULTS Consistent with prior cross-sectional studies, P/P homozygotes at PPARG P12A appeared more likely to develop diabetes than alanine carriers (hazard ratio, 1.24; 95% confidence interval, 0.99-1.57; P=0.07) with no interaction of genotype with intervention. There was a significant interaction of genotype with body mass index and waist circumference (P=0.03 and 0.002, respectively) with the alanine allele conferring less protection in more obese individuals. Neither PPARG P12A nor five other variants significantly affected the impact of troglitazone on insulin sensitivity in 340 participants at 1 yr. CONCLUSIONS The proline allele at PPARG P12A increases risk for diabetes in persons with impaired glucose tolerance, an effect modified by body mass index. In addition, PPARG P12A has little or no effect on the beneficial response to troglitazone.
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Affiliation(s)
- Jose C Florez
- Center for Human Genetic Research and Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston 02114, USA.
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Rondinone CM. Kinase-dependent pathways and the development of insulin resistance in hepatocytes. Expert Rev Endocrinol Metab 2007; 2:195-203. [PMID: 30754170 DOI: 10.1586/17446651.2.2.195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hepatic insulin resistance is considered to be a dominant component in the pathogenesis of fasting hyperglycemia in Type 2 diabetes. The role of nutrients, free fatty acids and secretory inflammatory factors released by visceral fat in the pathogenesis of liver insulin resistance requires clarification, but a number of signaling pathways and serine kinases have been implicated. These include the discovery of c-Jun N-terminal kinase, I κβ kinase, protein kinase C θ, δ and ε, and ribosomal protein S6 kinase 1 as critical regulators of insulin action and steatosis in liver. In this article, the causes and mechanisms involved in the development of hepatic insulin resistance, and the signaling pathways and kinases involved, will be discussed. Elucidation of the molecular mechanisms underlying regulation and specificity may prompt novel approaches to the pharmacological modulation of protein kinase activities involved in hepatic insulin resistance. This review will detail recent discoveries and highlight emerging kinase targets that hold potential to reduce hepatic insulin resistance and normalize blood glucose.
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Affiliation(s)
- Cristina M Rondinone
- a Hoffmann-La Roche, Department of Metabolic Diseases, 340 Kingsland Street Nutley, New Jersey 07110, USA.
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Hansen T, Drivsholm T, Urhammer SA, Palacios RT, Vølund A, Borch-Johnsen K, Pedersen O. The BIGTT test: a novel test for simultaneous measurement of pancreatic beta-cell function, insulin sensitivity, and glucose tolerance. Diabetes Care 2007; 30:257-62. [PMID: 17259491 DOI: 10.2337/dc06-1240] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Insulin resistance and impaired beta-cell function are key elements in the pathogenesis of type 2 diabetes. We aimed to develop valid algorithms for estimation of the insulin sensitivity index (S(I)) and acute insulin response (AIR) derived from simple and cheap physiological measurements that could be used in large-scale metabolic, genetic, and epidemiological studies. RESEARCH DESIGN AND METHODS For our purpose, data from an oral glucose tolerance test (OGTT) (18 samples during 240 min) and a tolbutamide-modified intravenous glucose tolerance test (IVGTT) (33 samples during 180 min) from 258 individuals with fasting plasma glucose <7 mmol/l and 2-h plasma glucose <7.8 mmol/l were used for model development and internal validation. Data from an additional 28 individuals were used for external validation. Bergman's minimal model was used to calculate S(I), and the trapezoidal method was used to calculate AIR(0-8 min). Multiple linear regression was applied to derive predictive equations of log(S(I)) and log(AIR(0-8 min)) using data on sex, BMI, plasma glucose, and serum insulin levels obtained during the OGTT. RESULTS We demonstrate that it is possible to obtain estimates of S(I) (BIGTT-S(I)) and AIR (BIGTT-AIR) that are highly correlated to IVGTT-derived values of S(I) (R(2) = 0.77) and AIR (R(2) = 0.54). In the two validation datasets we obtained similar results. CONCLUSIONS Data from OGTTs can provide accurate measures of insulin sensitivity and beta-cell function, which can be used in large scale metabolic, genetic, and epidemiological studies.
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Affiliation(s)
- Torben Hansen
- Steno Diabetes Center, Niels Steensens Vej 2, DK-2820 Gentofte, Denmark.
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25
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Florez JC, Jablonski KA, Kahn SE, Franks PW, Dabelea D, Hamman RF, Knowler WC, Nathan DM, Altshuler D. Type 2 diabetes-associated missense polymorphisms KCNJ11 E23K and ABCC8 A1369S influence progression to diabetes and response to interventions in the Diabetes Prevention Program. Diabetes 2007; 56:531-6. [PMID: 17259403 PMCID: PMC2267937 DOI: 10.2337/db06-0966] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The common polymorphisms KCNJ11 E23K and ABCC8 A1369S have been consistently associated with type 2 diabetes. We examined whether these variants are also associated with progression from impaired glucose tolerance (IGT) to diabetes and responses to preventive interventions in the Diabetes Prevention Program. We genotyped both variants in 3,534 participants and performed Cox regression analysis using genotype, intervention, and their interactions as predictors of diabetes incidence over approximately 3 years. We also assessed the effect of genotype on insulin secretion and insulin sensitivity at 1 year. As previously shown in other studies, lysine carriers at KCNJ11 E23K had reduced insulin secretion at baseline; however, they were less likely to develop diabetes than E/E homozygotes. Lysine carriers were less protected by 1-year metformin treatment than E/E homozygotes (P < 0.02). Results for ABCC8 A1369S were essentially identical to those for KCNJ11 E23K. We conclude that the lysine variant in KCNJ11 E23K leads to diminished insulin secretion in individuals with IGT. Given our contrasting results compared with case-control analyses, we hypothesize that its effect on diabetes risk may occur before the IGT-to-diabetes transition. We further hypothesize that the diabetes-preventive effect of metformin may interact with the impact of these variants on insulin regulation.
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Affiliation(s)
- Jose C Florez
- Diabetes Prevention Program Coordinating Center, Biostatistics Center, George Washington University, 6110 Executive Blvd., Suite 750, Rockville, MD 20852, USA.
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Chen SE, McMurtry JP, Walzem RL. Overfeeding-induced ovarian dysfunction in broiler breeder hens is associated with lipotoxicity. Poult Sci 2006; 85:70-81. [PMID: 16493948 DOI: 10.1093/ps/85.1.70] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In mammals, triacylglycerol (TAG) accumulation in nonadipose tissue, termed lipotoxicity, develops with obesity and can provoke insulin resistance, overt diabetes, and ovarian dysfunction. Leptin, an adipose tissue hormone, may mediate these effects. Feed-satiated broiler breeder hens manifest lipotoxicity-like symptoms. Changes in body and organ weights, hepatic and plasma TAG, nonesterified fatty acids (NEFA), ovarian morphology, and egg production in response to acute voluntary increases of feed intake were measured in 2 studies with Cobb 500 broiler breeder hens provided with either 145 or > or = 290 g of feed/d per hen for 10 d. In both studies, no hen fed 145 g of feed/d exhibited ovarian abnormalities, whereas approximately 50% of feed-satiated hens did. Egg production in feed-satiated hens was reduced from 73.3 to 55.8% (P = 0.001). Morphology indicated that apoptosis-induced atresia occurred in the hierarchical follicles. Fractional weight of yolk increased from 29.3 to 30.6% (P = 0.016) and no longer correlated to egg weight. Body, liver, and abdominal adipose weights were significantly greater (P < 0.05) in feed-satiated hens, as were plasma concentrations of glucose, NEFA, TAG, insulin, and leptin (P < 0.05). Feed-satiated hens with abnormal ovaries had significantly more liver and abdominal fat, greater plasma leptin and TAG concentrations, and more saturated fatty acids in plasma NEFA than did feed-satiated hens with normal ovaries. Differences in severity of lipotoxic metabolic and hormonal responses among feed-satiated hens were closely linked to the incidence of ovarian abnormalities and granulosa cell susceptibility to apoptosis and necrosis.
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Affiliation(s)
- S E Chen
- Department of Poultry Science, Texas A&M University, College Station 77843-2472, USA.
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27
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Abstract
An optimal diet is one that not only prevents nutrient deficiencies by providing sufficient nutrients and energy for human growth and reproduction, but that also promotes health and longevity and reduces the risk of diet-related chronic diseases. The composition of the optimal diet for women with polycystic ovary syndrome (PCOS) is not yet known, but such a diet must not only assist short term with weight management, symptoms and fertility, but also specifically target the long-term risks of type 2 diabetes, CVD and certain cancers. With insulin resistance and compensatory hyperinsulinaemia now recognised as a key factor in the pathogenesis of PCOS, it has become clear that reducing insulin levels and improving insulin sensitivity are an essential part of management. Diet plays a significant role in the regulation of blood glucose and insulin levels, yet research into the dietary management of PCOS is lacking and most studies have focused on energy restriction rather than dietary composition per se. On the balance of evidence to date, a diet low in saturated fat and high in fibre from predominantly low-glycaemic-index-carbohydrate foods is recommended. Because PCOS carries significant metabolic risks, more research is clearly needed.
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Affiliation(s)
- Kate Marsh
- Human Nutrition Unit, School of Molecular and Microbial Biosciences, University of Sydney, NSW Australia 2006.
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Zhang J, Holt H, Wang C, Hadid OH, Byrne CD. Expression of AdipoR1 in vivo in skeletal muscle is independently associated with measures of truncal obesity in middle-aged caucasian men. Diabetes Care 2005; 28:2058-60. [PMID: 16043761 DOI: 10.2337/diacare.28.8.2058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Junlong Zhang
- Endocrinology & Metabolism Unit, Developmental Origins of Health and Disease Division, University of Southampton, Level F, Central Block, Mailpoint 113, Southampton General Hospital, Southampton, SO16 6YD, UK
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29
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Cleasby ME, Dzamko N, Hegarty BD, Cooney GJ, Kraegen EW, Ye JM. Metformin prevents the development of acute lipid-induced insulin resistance in the rat through altered hepatic signaling mechanisms. Diabetes 2004; 53:3258-66. [PMID: 15561958 DOI: 10.2337/diabetes.53.12.3258] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Metformin reduces the incidence of progression to type 2 diabetes in humans with obesity or impaired glucose tolerance. We used an animal model to investigate whether metformin could prevent acute lipid-induced insulin resistance and the mechanisms involved. Metformin or vehicle was administered to rats daily for 1 week. Rats were studied basally, after 3.75 h of intralipid-heparin or glycerol infusion, or after 5 h of infusion with a hyperinsulinemic-euglycemic clamp between 3 and 5 h. Metformin had no effect on plasma triacylglycerol or nonesterified fatty acid concentrations and did not alter glucose turnover or gluconeogenic enzyme mRNA after lipid infusion. However, metformin normalized hepatic glucose output and increased liver glycogen during lipid infusion and clamp. Basal liver (but not muscle or fat) AMP-activated protein kinase activity was increased by metformin (by 310%; P < 0.01), associated with increased phosphorylation of acetyl CoA carboxylase. Postclamp liver but not muscle phosphorylated/total Akt protein was increased, whereas basal c-Jun NH2-terminal kinase-1 and -2 protein expression were reduced (by 39 and 53%, respectively; P < 0.05). Metformin also increased hepatic basal IkappaBalpha levels (by 260%; P < 0.001) but had no effect on tyrosine phosphorylation or expression of insulin receptor substrate-1 (IRS-1). In summary, metformin opposes the development of acute lipid-induced insulin resistance in the liver through alterations in multiple signaling pathways.
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Affiliation(s)
- Mark E Cleasby
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, Australia
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30
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Florez JC, Sjögren M, Burtt N, Orho-Melander M, Schayer S, Sun M, Almgren P, Lindblad U, Tuomi T, Gaudet D, Hudson TJ, Daly MJ, Ardlie KG, Hirschhorn JN, Altshuler D, Groop L. Association testing in 9,000 people fails to confirm the association of the insulin receptor substrate-1 G972R polymorphism with type 2 diabetes. Diabetes 2004; 53:3313-8. [PMID: 15561965 DOI: 10.2337/diabetes.53.12.3313] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The insulin receptor substrate (IRS)-1 is an important component of the insulin signal transduction cascade. Several reports suggest that a Gly-->Arg change in codon 972 is associated with type 2 diabetes and related traits, and a recent meta-analysis reported a modest but nominally significant association with type 2 diabetes (odds ratio [OR] 1.25 in favor of carriers of the Arg allele [95% CI 1.05-1.48). To test the reproducibility of the model in a recent meta-analysis, we examined genotype-phenotype correlation in three large Caucasian samples (not previously reported for this variant) totaling 9,000 individuals (estimated to have >95% power to obtain a P < 0.05 for the OR of 1.25 estimated in the meta-analysis). In our combined sample, comprising 4,279 case and 3,532 control subjects, as well as 1,189 siblings discordant for type 2 diabetes, G972R was not associated with type 2 diabetes (OR 0.96 [0.84-1.10], P = 0.60). Genotype at G972R had no significant effect on various measures of insulin secretion or insulin resistance in a set of Scandinavian samples in whom we had detailed phenotypic data. In contrast, the well-documented associations of peroxisome proliferator-activated receptor gamma P12A and Kir6.2 E23K with type 2 diabetes are both robustly observed in these 9,000 subjects, including an additional (previously unpublished) confirmation of Kir6.2 E23K and type 2 diabetes in the Polish and North American samples (combined OR 1.15 [1.05-1.26], P = 0.001). Despite genotyping 9,000 people and >95% power to reproduce the estimated OR from the recent meta-analysis, we were unable to replicate the association of the IRS-1 G972R polymorphism with type 2 diabetes.
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Affiliation(s)
- Jose C Florez
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
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Kaushal K, Heald AH, Siddals KW, Sandhu MS, Dunger DB, Gibson JM, Wareham NJ. The impact of abnormalities in IGF and inflammatory systems on the metabolic syndrome. Diabetes Care 2004; 27:2682-8. [PMID: 15505005 DOI: 10.2337/diacare.27.11.2682] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Low plasma levels of IGF-I, particularly when coupled with low levels of the potentially inhibitory IGF binding protein (IGFBP)-1 and higher levels of C-reactive protein (CRP), have been implicated in the pathogenesis of metabolic syndrome X and cardiovascular disease. We report the relative contributions of IGFBP-1 and CRP to the occurrence of the metabolic syndrome in a healthy population cohort to establish the extent to which these factors may contribute to subsequent risk of cardiovascular disease. RESEARCH DESIGN AND METHODS The volunteers in the study were all participants in the Ely study, a continuing population-based cohort in Ely, Cambridgeshire, U.K. Of 839 individuals studied, 154 (18.4%) fulfilled criteria for the metabolic syndrome. RESULTS Subjects with the metabolic syndrome had lower IGFBP-1 (14.4 microg/l [95% CI 12.9-16.0] vs. 25.4 [24.1-26.7], P < 0.001) and higher CRP (1.9 mg/l [1.6-2.2] vs. 1.0 [0.9-1.1], P < 0.001). Logistic regression, adjusted for age, sex, fasting insulin, and IGF-I, demonstrated a striking 14-fold increased risk for the metabolic syndrome (odds ratio 14.1 [4.1-48.4], P < 0.001) in individuals with a CRP value in the highest tertile and IGFBP-1 levels below the median. CONCLUSIONS The combination of a high CRP concentration coupled with a low IGFBP-1 results in a dramatic increase in an individual's risk of having the metabolic syndrome. Further elucidation of the biological processes linking the IGF and inflammatory systems may allow the identification of novel therapeutic targets for cardiovascular risk reduction.
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Affiliation(s)
- Kalpana Kaushal
- Department of Diabetes and Endocrinology, Hope Hospital, Stott Lane, Salford, UK
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32
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Florez JC, Burtt N, de Bakker PIW, Almgren P, Tuomi T, Holmkvist J, Gaudet D, Hudson TJ, Schaffner SF, Daly MJ, Hirschhorn JN, Groop L, Altshuler D. Haplotype structure and genotype-phenotype correlations of the sulfonylurea receptor and the islet ATP-sensitive potassium channel gene region. Diabetes 2004; 53:1360-8. [PMID: 15111507 DOI: 10.2337/diabetes.53.5.1360] [Citation(s) in RCA: 238] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The genes for the sulfonylurea receptor (SUR1; encoded by ABCC8) and its associated islet ATP-sensitive potassium channel (Kir6.2; encoded by KCNJ11) are adjacent to one another on human chromosome 11. Multiple studies have reported association of the E23K variant of Kir6.2 with risk of type 2 diabetes. Whether and how E23K itself-or other variant(s) in either of these two closely linked genes-influences type 2 diabetes remains to be fully determined. To better understand genotype-phenotype correlation at this important candidate gene locus, we 1) characterized haplotype structures across the gene region by typing 77 working, high-frequency markers spanning 207 kb and both genes; 2) performed association studies of E23K and nearby markers in >3,400 patients (type 2 diabetes and control) not previously reported in the literature; and 3) analyzed the resulting data for measures of insulin secretion. These data independently replicate the association of E23K with type 2 diabetes with an odds ratio (OR) in the new data of 1.17 (P = 0.003) as compared with an OR of 1.14 provided by meta-analysis of previously published, nonoverlapping data (P = 0.0002). We find that the E23K variant in Kir6.2 demonstrates very strong allelic association with a coding variant (A1369S) in the neighboring SUR1 gene (r(2) > 0.9) across a range of population samples, making it difficult to distinguish which gene and polymorphism in this region are most likely responsible for the reported association. We show that E23K is also associated with decreased insulin secretion in glucose-tolerant control subjects, supporting a mechanism whereby beta-cell dysfunction contributes to the common form of type 2 diabetes. Like peroxisome proliferator-activated receptor gamma, the SUR1/Kir6.2 gene region both contributes to the inherited risk of type 2 diabetes and encodes proteins that are targets for hypoglycemic medications, providing an intriguing link between the underlying mechanism of disease and validated targets for pharmacological treatment.
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Affiliation(s)
- Jose C Florez
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
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Bailhache E, Nguyen P, Krempf M, Siliart B, Magot T, Ouguerram K. Lipoproteins abnormalities in obese insulin-resistant dogs. Metabolism 2003; 52:559-64. [PMID: 12759884 DOI: 10.1053/meta.2003.50110] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Many studies have shown that obesity and low insulin sensitivity are associated with lipoprotein abnormalities, which are risk factors for coronary heart disease. The effects of insulin resistance on lipoprotein metabolism were investigated in hyperenergetic-fed beagle dogs, a new model of insulin resistance. Insulin resistance was assessed by the 3-hour euglycemic-hyperinsulinemic glucose clamp technique. Lipoproteins were separated by fast-protein liquid chromatography (FPLC) and lipid composition of the different lipoproteins was determined by enzymatic methods. Hyperenergetic diet was associated with a 43% +/- 5% increase in dog body weight and a reduction in insulin-mediated glucose uptake (28 +/- 3 to 16 +/- 1 mg. kg(-1). min(-1), P <.05). Low insulin sensitivity associated with obesity was related to an increase in plasma triglyceride (TG) through an increase in very-low-density lipoprotein (VLDL)-TG (0.071 +/- 0.020 v 0.382 +/- 0.242 mmol/L, P <.05) and high-density lipoprotein (HDL)-TG (0.025 +/- 0.012 v 0.242 +/- 0.143 mmol/L, P <.05). Other lipid abnormalities common in insulin resistant humans were also found: lower plasma HDL-cholesterol (4.690 +/- 0.151 v 3.937 +/- 0.141 mmol/L, P <.05) and higher plasma nonesterified fatty acids (NEFA) (0.974 +/- 0.094 v 1.590 +/- 0.127 mmol/L, P <.05) levels. These data show that this model of the insulin-resistant obese dog could be useful in studying insulin resistance-associated dyslipidemia.
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Affiliation(s)
- Edwige Bailhache
- Centre de Recherche en Nutrition Humaine, INSERM U539, CHU Nantes, France
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Variants in the APOC3 promoter insulin responsive element modulate insulin secretion and lipids in middle-aged men. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1637:200-6. [PMID: 12697301 DOI: 10.1016/s0925-4439(03)00021-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Variation in the insulin responsive element (IRE) of the APOC3 promoter has been shown to be associated with insulin and glucose concentrations after an oral glucose tolerance test (OGTT) in young healthy men. We evaluated two variants in the IRE (-455T>C and -482C>T) in the Ely study, a prospective cohort study of middle-aged men (n=223) and women (n=279), to determine if the effect of these variants on glucose homeostasis could be explained by altered nonesterified fatty acid (NEFA) levels and if these effects are modulated by age and gender. Both variants had significant effects on the 30-min insulin incremental response in men alone (-482C>T, P=0.007; -455T>C, P=0.0155), with rare allele homozygotes having a 33.3% and 23.3% lower insulin increment as compared to common allele homozygotes, respectively. Thirty-minute NEFA concentrations were also significantly associated with genotype in men and levels were approximately 10% higher in carriers homozygous for the rare alleles as compared to subjects homozygous for the common alleles (-482C>T, P=0.04; -455T>C, P=0.006). In addition, there was a strong interaction between both variants and cigarette smoking affecting fasting triglyceride levels in both men (interaction: -455T>C, P=0.02; -482C>T, P=0.008) and women (interaction: -455T>C, P=0.007; -482C>T, P=0.013). Taken together, the data shows that men who carry the rare alleles of the IRE variants have disturbed glucose homeostasis and an unfavourable lipid phenotype. The finding of an elevated 30-min NEFA may be an important mechanistic link between triglyceride-rich lipoprotein (TRL) metabolism and glucose homeostasis.
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Bailhache E, Ouguerram K, Gayet C, Krempf M, Siliart B, Magot T, Nguyen P. An insulin-resistant hypertriglyceridaemic normotensive obese dog model: assessment of insulin resistance by the euglycaemic hyperinsulinaemic clamp in combination with the stable isotope technique. J Anim Physiol Anim Nutr (Berl) 2003; 87:86-95. [PMID: 14511132 DOI: 10.1046/j.1439-0396.2003.00419.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many studies have shown that in humans insulin resistance (IR) is associated with obesity and hypertriglyceridaemia. The aim of our study was to develop slowly dietary-induced obesity in dogs through long-term overfeeding of a high-fat diet, and to characterize this IR, hypertriglyceridaemic and normotensive model. Insulin resistance was assessed by the euglycaemic hyperinsulinaemic clamp technique. The contribution of hepatic glucose production during the clamp was evaluated using a constant stable-isotope-labelled glucose infusion. Overfeeding a high-fat diet for 7 months was associated with a 43+/-5% body weight increase. Insulin resistance was characterized by hyperinsulinaemia in the unfed state (10+/-1 vs. 24+/-1 microU/ml, in healthy and obese dogs, respectively, p<0.02) and by a reduction of the insulin-mediated glucose uptake (28+/-3 vs. 16+/-1 mg/kg/min, p<0.02). Hepatic glucose production suppression under insulin infusion allowed to conclude that this reduced glucose uptake resulted from a decrease of insulin sensitivity in obese dogs. Furthermore, animals remained normotensive and exhibited a marked hypertriglyceridaemia (0.26+/-0.04 vs. 0.76+/-0.15 mmol/l, in healthy and obese dogs, respectively, p<0.02). Because hypertriglyceridaemia is the most common lipid abnormality in insulin-resistant humans, this dog with slowly induced obesity may constitute a good model to study the consequences of IR in lipid metabolism independently of vascular changes.
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Affiliation(s)
- E Bailhache
- USC INRA de Nutrition et Endocrinologie, Ecole nationale vétérinaire de Nantes, France
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Wolever TMS, Mehling C. Long-term effect of varying the source or amount of dietary carbohydrate on postprandial plasma glucose, insulin, triacylglycerol, and free fatty acid concentrations in subjects with impaired glucose tolerance. Am J Clin Nutr 2003; 77:612-21. [PMID: 12600851 DOI: 10.1093/ajcn/77.3.612] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Reducing the glycemic load (GL) is considered beneficial for managing insulin resistance. The GL can be reduced either by reducing carbohydrate intake or by reducing the glycemic index (GI). OBJECTIVE We studied whether these 2 dietary maneuvers have the same long-term effects on postprandial plasma glucose, insulin, triacylglycerol, and free fatty acid (FFA) concentrations in subjects with impaired glucose tolerance (IGT). DESIGN Thirty-four subjects with IGT were randomly assigned to high-carbohydrate, high-GI (high-GI); high-carbohydrate, low-GI (low-GI); and low-carbohydrate, high-monounsaturated fatty acid (MUFA) diets for 4 mo. Plasma glucose, insulin, and FFAs were measured from 0800 to 1600 at baseline in response to high-GI meals (60% carbohydrate, GI = 61, GL = 63) and after 4 mo in response to meals representative of the study diet. RESULTS Carbohydrate intake (% of energy), GI, and GL in the high-GI, low-GI, and MUFA groups (breakfast and lunch meals combined), respectively, were 60%, 61, and 63; 60%, 53, and 55; and 49%, 61, and 52. Compared with the change after 4 mo of the high-GI diet, both the low-GI and MUFA diets reduced 0-8-h mean plasma glucose concentrations by 0.35 mmol/L (P < 0.05). Mean plasma insulin was approximately 20% higher (P < 0.05) and FFAs approximately 12% lower (P < 0.05) after the low-GI diet than after the high-GI diet, with no significant effect of MUFA. Changes in 0-8-h mean plasma triacylglycerols in the 3 treatment groups differed significantly: -0.14, 0.04, and 0.18 mmol/L, respectively, with the high-GI, MUFA, and low-GI diets. CONCLUSIONS In subjects with IGT, reducing the GI of the diet for 4 mo reduced postprandial plasma glucose by the same amount as did reducing carbohydrate intake. The 2 dietary maneuvers had different effects on postprandial plasma insulin, triacylglycerols, and FFAs.
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Affiliation(s)
- Thomas M S Wolever
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, and the Clinical Nutrition and Risk Factor Modification Centre, St Michael's Hospital, Ontario, Canada.
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Nielsen EMD, Hansen L, Carstensen B, Echwald SM, Drivsholm T, Glümer C, Thorsteinsson B, Borch-Johnsen K, Hansen T, Pedersen O. The E23K variant of Kir6.2 associates with impaired post-OGTT serum insulin response and increased risk of type 2 diabetes. Diabetes 2003; 52:573-7. [PMID: 12540638 DOI: 10.2337/diabetes.52.2.573] [Citation(s) in RCA: 213] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The E23K polymorphism of the pancreatic beta-cell ATP-sensitive K(+) (K(ATP)) channel subunit Kir6.2 (KCNJ11) is associated with type 2 diabetes in whites, and a recent in vitro study of the E23K variant suggests that the association to diabetes might be explained by a slight inhibition of serum insulin release. In a study comprising 519 unrelated glucose-tolerant subjects, we addressed the question as to whether the E23K variant was related to reduced serum insulin release during an oral glucose tolerance test (OGTT). Furthermore, the polymorphism was examined in a case-control study comprising 803 type 2 diabetic patients and 862 glucose-tolerant control subjects. The E23K variant was associated with significant reductions in the insulinogenic index (P = 0.022) and serum insulin levels under the response curve during an OGTT (0-120 min) (P = 0.014) as well as with an increase in BMI (P = 0.013). In the present study, the association of the E23K polymorphism with type 2 diabetes was not significant (P = 0.26). However, the K23K genotype significantly associated with type 2 diabetes in a meta-analysis of white case and control subjects (n = 2,824, odds ratio [OR] 1.49, P = 0.00022). In conclusion, the widespread E23K polymorphism may have a diabetogenic effect by impairing glucose-induced insulin release and increasing BMI.
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Affiliation(s)
- Eva-Maria D Nielsen
- Steno Diabetes Center and Hagedorn Research Institute, Gentofte, Copenhagen, Denmark
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Franks PW, Wong MY, Luan J, Mitchell J, Hennings S, Wareham NJ. Non-esterified fatty acid levels and physical inactivity: the relative importance of low habitual energy expenditure and cardio-respiratory fitness. Br J Nutr 2002; 88:307-13. [PMID: 12207841 DOI: 10.1079/bjn2002663] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The fasting concentration of non-esterified fatty acids (NEFA) and the degree to which it declines during an oral glucose tolerance test are closely associated with insulin resistance and glucose intolerance. However, relatively few studies have described possible environmental determinants of NEFA concentrations. Physical activity is likely to be related to NEFA levels, but habitual activity level is difficult to quantify in epidemiological studies. In particular, it is unclear whether NEFA is more closely related to cardio-respiratory fitness or to habitual energy expenditure. In order to quantify these relationships, we analysed data from the Ely prospective population-based study in which 931 subjects underwent a glucose tolerance test with measurements of cardio-respiratory fitness and 4 d energy expenditure by heart-rate monitoring, a technique previously validated against whole-body calorimetry and doubly-labelled water. In order to estimate the latent variables of usual fitness and energy expenditure, a subset of 190 subjects underwent repeat testing on three further occasions over 1 year. In analyses adjusting only for age and sex, energy expenditure and cardio-respiratory fitness were both negatively correlated with the total area under the NEFA curve following the oral glucose load (standardised beta coefficients -0.030 and -0.039 respectively; both P<0.001) However, further adjustment for degree of obesity and bivariate measurement error suggested that the effect of energy expenditure was significantly greater than that for fitness (-0.047 and -0.005 respectively). These results suggest that the area under the NEFA curve in the oral glucose tolerance test, a measure of insulin sensitivity, is strongly associated with the habitual level of physical activity.
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Affiliation(s)
- Paul W Franks
- Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge, CB2 2SR, UK
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Meirhaeghe A, Luan J, Selberg-Franks P, Hennings S, Mitchell J, Halsall D, O'Rahilly S, Wareham NJ. The effect of the Gly16Arg polymorphism of the beta(2)-adrenergic receptor gene on plasma free fatty acid levels is modulated by physical activity. J Clin Endocrinol Metab 2001; 86:5881-7. [PMID: 11739457 DOI: 10.1210/jcem.86.12.8103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The lipolytic effects of catecholamines are mediated through members of the beta(2)-adrenergic receptor (BAR-2) family. Previous studies have suggested that genetic variants in the BAR-2 gene may be associated with obesity in some populations. To our knowledge, no studies have directly examined the effects of this polymorphism on circulating nonesterified fatty acid (NEFA) levels. To explore this issue further, a cohort of 604 Caucasian individuals (aged 40-65 yr) was genotyped for a common polymorphism in the BAR-2 gene (Gly16Arg), and the relationships between genotype, body mass index (BMI), NEFA, and lipid levels were examined. Women bearing the Arg16 allele had higher BMI values (P < 0.01) than Gly16Gly women. Women carriers of the Arg16Arg genotype had lower fasting plasma NEFAs (P < 0.01) and greater suppression of NEFAs (P < 0.01) after an oral glucose load than women bearing the Gly16 allele. In multivariate analysis after adjustment for age, sex, and smoking status, the interaction between the BAR-2 genotype and BMI in determining fasting NEFA concentrations was statistically significant (P < 0.05). The availability of objective measures of total energy expenditure in this population permitted the further examination of interactions, particularly that between genotype and physical activity. In the population as a whole, after adjustment for confounding by age, smoking, and BMI, the effect of the Arg16Arg genotype on the suppression of NEFA levels was modified by physical activity level (P for interaction <0.05). These data suggest the existence in this population of a gene-physical activity interaction on NEFA levels.
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Affiliation(s)
- A Meirhaeghe
- Department of Medicine, University of Cambridge, Cambridge CB2 2SR, United Kingdom
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Talmud PJ, Palmen J, Luan J, Flavell D, Byrne CD, Waterworth DM, Wareham NJ. Variation in the promoter of the human hormone sensitive lipase gene shows gender specific effects on insulin and lipid levels: results from the Ely study. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1537:239-44. [PMID: 11731226 DOI: 10.1016/s0925-4439(01)00076-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We previously identified a hormone sensitive lipase (HSL) promoter variant, -60C>G, which in vitro exhibits 40% reduced promoter activity. In this study we examined the effect of the -60C>G on glycemic and lipid measures in the population based Ely study of metabolic function and insulin resistance in 218 middle-aged men and 276 middle-aged women. Adipose tissue HSL is the rate-limiting step in triglyceride lipolysis, generating free fatty acids for energy utilization. HSL is also expressed in pancreatic beta-cells where its activity therefore may affect insulin secretion. In the women, carriers of the HSL -60G allele had significantly lower fasting insulin levels (P=0.0005) and a lower total area under the curve for insulin during the oral glucose tolerance test (P=0.005). There was no demonstrable association in men with these measures of insulin sensitivity but carriers of the -60G allele had significantly lower fasting non-esterified fatty acid (NEFA) levels (P=0.025) and higher low density lipoprotein cholesterol levels (P=0.02) than men who were non-carriers. This study provides additional evidence for a role for HSL in the development of insulin resistance, from which carriers of the -60G allele, associated here with markers of insulin sensitivity in women, and with lower NEFA levels in men, might be protected.
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Affiliation(s)
- P J Talmud
- Division of Cardiovascular Genetics, Department of Medicine, Royal Free and University College Medical School, The Rayne Institute, London, UK.
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Hanley AJ, McKeown-Eyssen G, Harris SB, Hegele RA, Wolever TM, Kwan J, Connelly PW, Zinman B. Cross-sectional and prospective associations between proinsulin and cardiovascular disease risk factors in a population experiencing rapid cultural transition. Diabetes Care 2001; 24:1240-7. [PMID: 11423509 DOI: 10.2337/diacare.24.7.1240] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To examine cross-sectional and prospective associations between proinsulin and cardiovascular disease risk factors using data from a population-based study of type 2 diabetes among Native Canadians. RESEARCH DESIGN AND METHODS Between 1993 and 1995, 72% of eligible members of a Native Canadian community participated in a baseline diabetes prevalence survey. Fasting samples were collected for glucose, C-peptide, proinsulin, lipids, and apolipoproteins. A 75-g oral glucose tolerance test was administered, and a second sample for glucose was drawn after 120 min. Blood pressure and waist circumference were determined. In the present study, subjects with normal glucose tolerance (NGT) (n = 505) and impaired glucose tolerance (IGT) (n = 74) were included in cross-sectional analyses. In 1998, 95 individuals who had IGT or NGT at baseline with an elevated 2-h glucose concentration (> or = 7.0 mmol/l) participated in a follow-up evaluation using the protocol used at baseline. Cross-sectional and prospective associations between proinsulin and cardiovascular risk factors were assessed using correlation and multiple linear regression analyses. RESULTS After adjustment for covariates including age, sex, C-peptide, waist circumference, and glucose tolerance status, fasting proinsulin concentration was significantly associated with concurrently measured lipid and apolipoprotein concentrations (triglycerides: r = 0.18, P < 0.0001; total cholesterol: r = 0.10, P = 0.02; LDL cholesterol: r = 0.11, P = 0.01; HDL cholesterol: r = -0.16, P = 0.0002; apolipoprotein (apo) B: r = 0.17, P < 0.0001; apoAI: r = -0.11, P = 0.008). In the adjusted prospective analysis, baseline triglycerides, HDL cholesterol, and apoB were associated with changes over time in proinsulin (r = 0.23, P = 0.04; r = -0.30, P = 0.01; r = 0.23, P = 0.04; respectively). CONCLUSIONS These results confirm previously reported cross-sectional associations between proinsulin and lipid concentrations. In addition, an unexpected association between baseline lipids and proinsulin change was documented.
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Affiliation(s)
- A J Hanley
- Department of Public Health Sciences, University of Toronto, Toronto, Ontario, Canada
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Abstract
Essential hypertension is frequently associated with the metabolic abnormalities of insulin resistance and dyslipidemia. This prevalent clustering of multiple cardiovascular risk factors may help explain the less-than-expected improvement in coronary heart disease mortality provided by simple blood pressure reduction alone. Many antihypertensive medications effectively reduce blood pressure while providing no benefit or even causing a detrimental effect on the associated metabolic abnormalities. beta-Blockers and diuretics tend to negatively affect both glucose tolerance and plasma lipids. Calcium channel blockers, angiotensin converting enzyme inhibitors, and angiotensin II receptor blockers are most often found to be metabolically neutral. alpha-Blockers provide the most favorable metabolic effects of antihypertensive agents by improving both insulin sensitivity and dyslipidemia. The multiple physiologic mechanisms by which blood pressure medications alter plasma lipids are discussed in detail. The effects of antihypertensive medications on postprandial lipid metabolism and the associated postprandial lipemia-induced endothelial dysfunction deserve special attention.
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Affiliation(s)
- R D Brook
- Division of Hypertension, 3918 Taubman Center, University of Michigan, 1500 E. Medical Center Drive, Ann Arbor, MI 48104, USA.
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Tsihlias EB, Gibbs AL, McBurney MI, Wolever TM. Comparison of high- and low-glycemic-index breakfast cereals with monounsaturated fat in the long-term dietary management of type 2 diabetes. Am J Clin Nutr 2000; 72:439-49. [PMID: 10919939 DOI: 10.1093/ajcn/72.2.439] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Results of 6-wk studies suggest that high-carbohydrate diets are deleterious for people with type 2 diabetes. OBJECTIVE Our objective was to see whether long-term replacement of dietary monounsaturated fatty acids (MUFAs) with carbohydrate from breakfast cereals with either a high or a low glycemic index (GI) affected blood glucose and lipids in subjects with type 2 diabetes. DESIGN Subjects with type 2 diabetes (n = 91) were randomly assigned to receive approximately 10% of energy from a low-GI breakfast cereal, a high-GI cereal, or oil or margarine containing MUFA for 6 mo. Eating breakfast cereal was prohibited for subjects in the MUFA group. RESULTS Seventy-two subjects completed the trial. The subjects who received cereals consumed approximately 10% more energy from carbohydrate than did the subjects in the MUFA group. Changes in glycated hemoglobin, body weight, and fasting cholesterol and triacylglycerol did not differ significantly among groups. HDL cholesterol increased by approximately 10% in the MUFA group compared with subjects who consumed either high- or low-GI cereals (P = 0.002). The ratio of total to HDL cholesterol was higher in the subjects who consumed the high-GI cereal than in the MUFA group at 3 mo but not at 6 mo (diet x time interaction, P = 0.041). During 8-h metabolic profiles, mean plasma insulin was higher and mean free fatty acids were lower in the 2 cereal groups than in the MUFA group (P < 0.05). CONCLUSIONS A 10% increase in carbohydrate intake associated with breakfast cereal consumption had no deleterious effects on glycemic control or blood lipids over 6 mo in subjects with type 2 diabetes. The increase in plasma insulin and the reduction in free fatty acids associated with higher carbohydrate intake may reduce the rate of progression of diabetes.
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Affiliation(s)
- E B Tsihlias
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Canada
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Carlsson M, Wessman Y, Almgren P, Groop L. High levels of nonesterified fatty acids are associated with increased familial risk of cardiovascular disease. Arterioscler Thromb Vasc Biol 2000; 20:1588-94. [PMID: 10845876 DOI: 10.1161/01.atv.20.6.1588] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To address the question of whether elevated concentrations of nonesterified fatty acids (NEFAs) are associated with an increased risk of cardiovascular disease, we measured NEFA concentrations in 140 diabetic and 343 nondiabetic unrelated Swedish subjects with a family history of type 2 diabetes and related the findings to history of cardiovascular disease in their parents. Parents of nondiabetic offspring belonging to the quartile of highest NEFA concentrations had a higher risk of myocardial infarction (35% versus 16%, P<0.01) and stroke (45% versus 16%, P<0.0005) than did parents of offspring from the lowest NEFA quartile. In a multiple logistic regression analysis, a high NEFA concentration in offspring was significantly associated with myocardial infarction and stroke in their parents. No such relationship was observed between diabetic offspring and their parents. Assuming that the same relationship between NEFA concentrations and cardiovascular disease is seen in the offspring and their parents, the findings suggest that elevated NEFA concentration is a risk factor for cardiovascular disease and could be pathogenically involved in the atherosclerotic process.
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Affiliation(s)
- M Carlsson
- Department of Endocrinology, Malmö University Hospital, University of Lund, Lund, Sweden
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Davies MJ, Raymond NT, Day JL, Hales CN, Burden AC. Impaired glucose tolerance and fasting hyperglycaemia have different characteristics. Diabet Med 2000; 17:433-40. [PMID: 10975211 DOI: 10.1046/j.1464-5491.2000.00246.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS Use of the oral glucose tolerance test (OGTT) to define glucose intolerance in the general population may bias towards selection of those with insulin resistance. Beta cell function and insulin resistance markers were analysed in four groups: controls (n = 101); fasting hyperglycaemia (FH, n 45); impaired glucose tolerance; (IGT, n = 16) and those with features of both FH and IGT ('Both', n = 30). METHODS Subjects underwent an OGTT. Plasma glucose, fasting lipid profiles, fasting, 30 and 120 min insulin were measured and beta cell function (% B) and insulin sensitivity (% S) assessed by homeostatic model assessment (HOMA) RESULTS: The FH group compared to controls had a significantly lower % B. The IGT group compared to controls had features of insulin resistance (higher body mass index (BMI), systolic blood pressure and 2 h insulin concentration). Subjects with 'both' IGT and FH had features of insulin resistance (higher BMI, systolic and diastolic blood pressure and triglyceride concentration) as well as beta cell dysfunction with a lower % B and 30 min insulin-glucose ratio compared to controls. There was a preponderance of males in this group. In all, 192 subjects' 30-min insulin concentration and incremental insulin response showed only a significantly negative correlation with fasting glucose concentration. In a linear regression analysis, a low 30-min insulin-glucose ratio was only a significant factor in the fasting glucose model. Thus, higher fasting glucose concentrations appear to be associated with beta cell dysfunction. However, HbA1 only showed a significant correlation with 120-min glucose, not fasting glucose concentration. CONCLUSIONS In those with milder degrees of glucose intolerance, FH is associated with beta cell dysfunction and those with IGT and a relatively 'normal' fasting glucose have features of the insulin resistance syndrome.
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Affiliation(s)
- M J Davies
- Department of Diabetes and Endocrinology, Leicester Royal Infirmary, UK
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46
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Maison P, Byrne CD, Hales CN, Wareham NJ. Hypertension and its treatment influence changes in fasting nonesterified fatty acid concentrations: a link between the sympathetic nervous system and the metabolic syndrome? Metabolism 2000; 49:81-7. [PMID: 10647068 DOI: 10.1016/s0026-0495(00)90788-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In previous studies, a cross-sectional association has been described between blood pressure (BP) and nonesterified fatty acid (NEFA) concentrations. The direction of causality, and thus, the mechanism explaining this relationship, remains uncertain. Therefore, we analyzed a prospective population-based cohort of 937 subjects who underwent an oral glucose tolerance test (OGTT) on two occasions separated by 4.5 years. In cross-sectional analysis, NEFA measures were correlated with systolic and diastolic BP, both at baseline and at follow-up study. In longitudinal analysis, baseline systolic and diastolic BP predicted changes in fasting NEFA levels (both P < .01). However, baseline NEFA levels did not predict change in BR In multivariate analysis, the relationship between baseline BP and change in fasting NEFA was independent of age and sex. Obesity and its interaction with BP did not explain this association. Absolute changes in NEFA concentrations were greater among subjects who were hypertensive at baseline compared with the normotensive individuals. This change was greater in subjects treated with diuretics compared with those treated with beta-adrenergic antagonists (P < .01), an observation that provides support for a role of sympathetic nervous system (SNS) activity in explaining the relationship between BP and NEFA concentration.
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Affiliation(s)
- P Maison
- University of Cambridge Department of Community Medicine, Institute of Public Health, Addenbrooke's Hospital, UK
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Playford D, Watts GF. Endothelial dysfunction, insulin resistance and diabetes: exploring the web of causality. AUSTRALIAN AND NEW ZEALAND JOURNAL OF MEDICINE 1999; 29:523-34. [PMID: 10868531 DOI: 10.1111/j.1445-5994.1999.tb00754.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- D Playford
- University Department of Medicine, University of Western Australia, Royal Perth Hospital
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48
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Byrne CD. Triglyceride-rich lipoproteins: are links with atherosclerosis mediated by a procoagulant and proinflammatory phenotype? Atherosclerosis 1999; 145:1-15. [PMID: 10428291 DOI: 10.1016/s0021-9150(99)00110-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Specific treatment that primarily reduces low density lipoprotein cholesterol (LDLc) levels improves survival of patients with pre-existing vascular disease by 20-30%. Failure to produce a more marked improvement in outcome is most likely explained by: (1) the observation from angiographic studies that established atherosclerotic vascular disease (AVD) is largely irreversible with current therapy and (2) other important factors cause AVD besides LDLc. One such risk factor predicting development of AVD is the atherogenic lipoprotein phenotype (ALP), comprising abnormalities of triglyceride enriched lipoproteins, high density lipoprotein cholesterol (HDLc) and small dense LDL particles. Despite strong links between the ALP and AVD, the mechanism(s) linking these relatively subtle lipoprotein abnormalities to vascular disease is poorly understood. Recent evidence suggests that a procoagulant and proinflammatory state develops within the vasculature, perhaps mediating a link between the ALP and AVD. The purpose of this review is to discuss mechanisms by which the ALP, and specifically, certain triglyceride-rich lipoproteins, may cause AVD by adverse affects on platelet function, coagulation and vascular inflammation. All rights reserved.
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Affiliation(s)
- C D Byrne
- University Department of Medicine, Southampton General Hospital, UK.
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Snehalatha C, Satyavani K, Sivasankari S, Vijay V, Ramachandran A. Insulin secretion and action in different stages of glucose tolerance in Asian Indians. Diabet Med 1999; 16:408-14. [PMID: 10342341 DOI: 10.1046/j.1464-5491.1999.00084.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To evaluate the sequence of changes in insulin secretion and action in different stages of glucose tolerance and the effect of obesity on insulin profile in South Indian adults. Blood samples from 260 consecutive cases with no known history of diabetes were collected. Plasma insulin levels were measured during a 75-g oral glucose tolerance test. Insulin resistance (IR) was calculated, using the homeostasis model assessment (HOMA). An index of insulin secretion was derived as the ratio of incremental insulin at 30 min divided by 30 minute plasma glucose (delta I/G). RESULTS Normoglycaemia was present in 164, impaired glucose tolerance (IGT) in 60 and diabetes in 36 subjects. Fasting and 2 h insulin secretion showed bell shaped curves with increasing plasma glucose. The peak values corresponded to the cut-off values used for the diagnosis of clinical diabetes. IR was higher in obese than in nonobese, nondiabetic subjects but the effect of obesity on IR was not found in subjects with diabetes. IGT was associated with higher IR, but not with evidence of a beta-cell defect. CONCLUSIONS Evaluation of insulin resistance and beta-cell function in different stages of glucose tolerance indicate that insulin resistance is manifested in the early stage of glucose intolerance in South Indians, i.e. IGT. A beta-cell defect was mostly found in people with diabetes. The beta-cell defect is more common in diabetes among the nonobese.
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Affiliation(s)
- C Snehalatha
- Diabetes Research Centre, Royapuram, Madras, India.
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50
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Koopmans SJ, Kushwaha RS, DeFronzo RA. Chronic physiologic hyperinsulinemia impairs suppression of plasma free fatty acids and increases de novo lipogenesis but does not cause dyslipidemia in conscious normal rats. Metabolism 1999; 48:330-7. [PMID: 10094109 DOI: 10.1016/s0026-0495(99)90081-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Type 2 diabetes mellitus and obesity are characterized by fasting hyperinsulinemia, insulin resistance with respect to glucose metabolism, elevated plasma free fatty acid (FFA) levels, hypertriglyceridemia, and decreased high-density lipoprotein (HDL) cholesterol. An association between hyperinsulinemia and dyslipidemia has been suggested, but the causality of the relationship remains uncertain. Therefore, we infused eight 12-week-old male catheterized conscious normal rats with insulin (1 mU/min) for 7 days while maintaining euglycemia using a modification of the glucose clamp technique. Control rats (n = 8) received vehicle infusion. Baseline FFAs were 1.07+/-0.13 mmol/L, decreased to 0.57+/-0.10 (P < .05) upon initiation of the insulin infusion, and gradually increased to 0.95+/-0.12 by day 7 (P = NS vbaseline). On day 7 after a 6-hour fast, plasma insulin, glucose, and FFA levels in control and chronically hyperinsulinemic rats were 32+/-5 versus 116+/-21 mU/L (P < .005), 122+/-4 versus 129+/-8 mg/dL (P = NS), and 1.13+/-0.18 versus 0.95+/-0.12 mmol/L (P = NS); total plasma triglyceride and cholesterol levels were 78+/-7 versus 66+/-9 mg/dL (P = NS) and 50+/-3 versus 47+/-2 mg/dL (P = NS), respectively. Very-low-density lipoprotein (VLDL) + intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and HDL2 and HDL3 subfractions of plasma triglyceride and cholesterol were similar in control and hyperinsulinemic rats. Plasma FFA correlated positively with total (r = .61, P < .005) triglycerides. On day 7 after an 8-hour fast, hyperinsulinemic-euglycemic clamps with 3-3H-glucose infusion were performed in all rats. Chronically hyperinsulinemic rats showed peripheral insulin resistance (glucose uptake, 15.8+/-0.8 v 19.3+/-1.4 mg/kg x min, P < .02) but normal suppression of hepatic glucose production (HGP) compared with control rats (4.3+/-1.0 v 5.6+/-1.4 mg/kg x min, P = NS). De novo tissue lipogenesis (3-3H-glucose incorporation into lipids) was increased in chronically hyperinsulinemic versus control rats (0.90+/-0.10 v 0.44+/-0.08 mg/kg x min, P < .005). In conclusion, chronic physiologic hyperinsulinemia (1) causes insulin resistance with regard to the suppression of plasma FFA levels and increases lipogenesis; (2) induces peripheral but not hepatic insulin resistance with respect to glucose metabolism; and (3) does not cause an elevation in VLDL-triglyceride or a reduction in HDL-cholesterol.
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Affiliation(s)
- S J Koopmans
- Department of Medicine, University of Texas Health Science Center, San Antonio 78284-7886, USA
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