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Ahrén B, Pacini G. Glucose effectiveness: Lessons from studies on insulin-independent glucose clearance in mice. J Diabetes Investig 2021; 12:675-685. [PMID: 33098240 PMCID: PMC8088998 DOI: 10.1111/jdi.13446] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/15/2020] [Accepted: 10/19/2020] [Indexed: 01/07/2023] Open
Abstract
Besides insulin-mediated transport of glucose into the cells, an important role is also played by the non-insulin-mediated transport. This latter process is called glucose effectiveness (acronym SG ), which is estimated by modeling of glucose and insulin data after an intravenous glucose administration, and accounts for ≈70% of glucose disposal. This review summarizes studies on SG , mainly in humans and rodents with focus on results achieved in model experiments in mice. In humans, SG is reduced in type 2 diabetes, in obesity, in liver cirrhosis and in some elderly populations. In model experiments in mice, SG is independent from glucose levels, but increases when insulin secretion is stimulated, such as after administration of the incretin hormones, glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide. SG is reduced in insulin resistance induced by high-fat feeding and by exogenous administration of glucagon. Glucose-dependent (insulin-independent) glucose disposal is therefore important for glucose elimination, and it is also well regulated. It might be of pathophysiological relevance for the development of type 2 diabetes, in particular during insulin resistance, and might also be a target for glucose-reducing therapy. Measuring SG is essentially important when carrying out metabolic studies to understand glucose homeostasis.
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Affiliation(s)
- Bo Ahrén
- Department of Clinical Sciences LundLund UniversityLundSweden
| | - Giovanni Pacini
- Metabolic UnitInstitute of Neurosciences (IN‐CNR)PadovaItaly
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Hu S, Lu Y, Tura A, Pacini G, D’Argenio DZ. An Analysis of Glucose Effectiveness in Subjects With or Without Type 2 Diabetes via Hierarchical Modeling. Front Endocrinol (Lausanne) 2021; 12:641713. [PMID: 33854483 PMCID: PMC8039510 DOI: 10.3389/fendo.2021.641713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/24/2021] [Indexed: 11/20/2022] Open
Abstract
Glucose effectiveness, defined as the ability of glucose itself to increase glucose utilization and inhibit hepatic glucose production, is an important mechanism maintaining normoglycemia. We conducted a minimal modeling analysis of glucose effectiveness at zero insulin (GEZI) using intravenous glucose tolerance test data from subjects with type 2 diabetes (T2D, n=154) and non-diabetic (ND) subjects (n=343). A hierarchical statistical analysis was performed, which provided a formal mechanism for pooling the data from all study subjects, to yield a single composite population model that quantifies the role of subject specific characteristics such as weight, height, age, sex, and glucose tolerance. Based on the resulting composite population model, GEZI was reduced from 0.021 min-1 (standard error - 0.00078 min-1) in the ND population to 0.011 min-1 (standard error - 0.00045 min-1) in T2D. The resulting model was also employed to calculate the proportion of the non-insulin-dependent net glucose uptake in each subject receiving an intravenous glucose load. Based on individual parameter estimates, the fraction of total glucose disposal independent of insulin was 72.8% ± 12.0% in the 238 ND subjects over the course of the experiment, indicating the major contribution to the whole-body glucose clearance under non-diabetic conditions. This fraction was significantly reduced to 48.8% ± 16.9% in the 30 T2D subjects, although still accounting for approximately half of the total in the T2D population based on our modeling analysis. Given the potential application of glucose effectiveness as a predictor of glucose intolerance and as a potential therapeutic target for treating diabetes, more investigations of glucose effectiveness in other disease conditions can be conducted using the hierarchical modeling framework reported herein.
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Affiliation(s)
- Shihao Hu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Yuzhi Lu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Andrea Tura
- Metabolic Unit, CNR Institute of Neuroscience, Padova, Italy
| | | | - David Z. D’Argenio
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
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Zhu M, Liu X, Liu W, Lu Y, Cheng J, Chen Y. β cell aging and age-related diabetes. Aging (Albany NY) 2021; 13:7691-7706. [PMID: 33686020 PMCID: PMC7993693 DOI: 10.18632/aging.202593] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/23/2020] [Indexed: 02/05/2023]
Abstract
Type 2 diabetes is characterized by insulin resistance and loss of β cell mass and function. Aging is considered as a major risk factor for development of type 2 diabetes. However, the roles of pancreatic β cell senescence and systemic aging in the pathogenesis of type 2 diabetes in elderly people remain poorly understood. In this review, we aimed to discuss the current findings and viewpoints focusing on β cell aging and the development of type 2 diabetes.
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Affiliation(s)
- Min Zhu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Xiaohong Liu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Wen Liu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Yanrong Lu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Jingqiu Cheng
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Younan Chen
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, P.R. China
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Ehrhardt N, Cui J, Dagdeviren S, Saengnipanthkul S, Goodridge HS, Kim JK, Lantier L, Guo X, Chen YDI, Raffel LJ, Buchanan TA, Hsueh WA, Rotter JI, Goodarzi MO, Péterfy M. Adiposity-Independent Effects of Aging on Insulin Sensitivity and Clearance in Mice and Humans. Obesity (Silver Spring) 2019; 27:434-443. [PMID: 30801985 PMCID: PMC6474357 DOI: 10.1002/oby.22418] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/21/2018] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Aging is associated with impaired insulin sensitivity and increased prevalence of type 2 diabetes. However, it remains unclear whether aging-associated insulin resistance is due to increased adiposity or other age-related factors. To address this question, the impact of aging on insulin sensitivity was investigated independently of changes in body composition. METHODS Cohorts of mice aged 4 to 8 months ("young") and 18 to 27 months ("aged") exhibiting similar body composition were characterized for glucose metabolism on chow and high-fat diets. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp analyses. The relationship between aging and insulin resistance in humans was investigated in 1,250 nondiabetic Mexican Americans who underwent hyperinsulinemic-euglycemic clamps. RESULTS In mice with similar body composition, age had no detrimental effect on plasma glucose and insulin levels. While aging did not diminish glucose tolerance, hyperinsulinemic-euglycemic clamps demonstrated impaired insulin sensitivity and reduced insulin clearance in aged mice on chow and high-fat diets. Consistent with results in the mouse, age remained an independent determinant of insulin resistance after adjustment for body composition in Mexican American males. CONCLUSIONS This study demonstrates that in addition to altered body composition, adiposity-independent mechanisms also contribute to aging-associated insulin resistance in mice and humans.
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Affiliation(s)
- Nicole Ehrhardt
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Jinrui Cui
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Sezin Dagdeviren
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Suchaorn Saengnipanthkul
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Helen S. Goodridge
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Jason K. Kim
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37235, USA
| | - Xiuqing Guo
- Institute for Translational Genomics and Population Sciences, Los Angeles BioMedical Research Institute and Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Yii-Der I. Chen
- Institute for Translational Genomics and Population Sciences, Los Angeles BioMedical Research Institute and Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Leslie J. Raffel
- Department of Pediatrics, Division of Genetic and Genomic Medicine, University of California, Irvine, CA 92697, USA
| | - Thomas A. Buchanan
- Department of Physiology and Biophysics and Department of Medicine, Keck School of Medicine of USC, Los Angeles, CA 90033, USA
| | - Willa A. Hsueh
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA
| | - Jerome I. Rotter
- Institute for Translational Genomics and Population Sciences, Los Angeles BioMedical Research Institute and Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Mark O. Goodarzi
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Corresponding authors: Mark O. Goodarzi () and Miklós Péterfy () Tel: +1 909 706 3949
| | - Miklós Péterfy
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Corresponding authors: Mark O. Goodarzi () and Miklós Péterfy () Tel: +1 909 706 3949
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Morettini M, Di Nardo F, Burattini L, Fioretti S, Göbl C, Kautzky-Willer A, Pacini G, Tura A. Assessment of glucose effectiveness from short IVGTT in individuals with different degrees of glucose tolerance. Acta Diabetol 2018; 55:1011-1018. [PMID: 29931422 DOI: 10.1007/s00592-018-1182-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/12/2018] [Indexed: 02/06/2023]
Abstract
AIMS Minimal model analysis of intravenous glucose tolerance test (IVGTT) data represents the reference method to assess insulin sensitivity (SI) and glucose effectiveness (SG) that quantify the insulin-dependent and insulin-independent processes of glucose disappearance, respectively. However, test duration (3 h) and need for modeling expertise limit the applicability of this method. Aim of this study was providing a simple predictor of SG applicable to short test (1 h), as previously done with SI. METHODS Three groups of subjects reflecting different glucose tolerance degrees underwent a 3 h IVGTT: subjects with normal glucose tolerance (NGT, n = 164), with defective glucose regulation (DGR, n = 191), and with type 2 diabetes (T2D, n = 39). Minimal model analysis provided reference SG and its components at zero (GEZI) and basal (BIE) insulin. The simple predictor CSG (calculated SG) was described by the formula CSG = α0 + α1 × KG/Gpeak, being KG the glucose disappearance rate (between 10 and 50 min) and Gpeak the maximum of the glucose curve during the test; α0 and α1 coefficients were provided by linear regression analysis. RESULTS CSG and SG showed a markedly significant relationship in the whole dataset (r = 0.72, p < 0.0001) and in the single groups (r = 0.70 in NGT, r = 0.71 in DGR and r = 0.70 in T2D, p < 0.0001 for all); α1 × KG/Gpeak was significantly related to GEZI (r ≥ 0.60). CONCLUSIONS The interest for insulin-independent glucose disappearance is increasing, due to the recent availability of SGLT2 pharmacological agents, lowering glycemic levels without requiring insulin action. This study proposes a reliable predictor of SG based on IVGTT lasting 1 h only, and not requiring mathematical modeling skills.
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Affiliation(s)
- Micaela Morettini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Francesco Di Nardo
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Laura Burattini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Sandro Fioretti
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Christian Göbl
- Division of Obstetrics and Feto-maternal Medicine, Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria
| | - Alexandra Kautzky-Willer
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Giovanni Pacini
- Metabolic Unit, CNR Institute of Neuroscience, Corso Stati Uniti 4, 35127, Padova, Italy
| | - Andrea Tura
- Metabolic Unit, CNR Institute of Neuroscience, Corso Stati Uniti 4, 35127, Padova, Italy.
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de Jesús Garduno-Garcia J, Gastaldelli A, DeFronzo RA, Lertwattanarak R, Holst JJ, Musi N. Older Subjects With β-Cell Dysfunction Have an Accentuated Incretin Release. J Clin Endocrinol Metab 2018; 103:2613-2619. [PMID: 29672742 PMCID: PMC6669818 DOI: 10.1210/jc.2018-00260] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/11/2018] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Insulin secretion (IS) declines with age, which increases the risk of impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) in older adults. IS is regulated by the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). Here we tested the hypotheses that incretin release is lower in older adults and that this decline is associated with β-cell dysfunction. RESEARCH DESIGN A total of 40 young (25 ± 3 years) and 53 older (74 ± 7 years) lean nondiabetic subjects underwent a 2-hour oral glucose tolerance test (OGTT). Based on the OGTT, subjects were divided into three groups: young subjects with normal glucose tolerance (Y-NGT; n = 40), older subjects with normal glucose tolerance (O-NGT; n = 32), and older subjects with IGT (O-IGT; n = 21). MAIN OUTCOME MEASURES Plasma insulin, C-peptide, GLP-1, and GIP concentrations were measured every 15 to 30 minutes. We quantitated insulin sensitivity (Matsuda index) and insulin secretory rate (ISR) by deconvolution of C-peptide with the calculation of β-cell glucose sensitivity. RESULTS Matsuda index, early phase ISR (0 to 30 minutes), and parameters of β-cell function were lower in O-IGT than in Y-NGT subjects but not in O-NGT subjects. GLP-1 concentrations were elevated in both older groups [GLP-1 area under the curve (AUC)0-120 was 2.8 ± 0.1 in Y-NGT, 3.8 ± 0.5 in O-NGT, and 3.7 ± 0.4 nmol/L∙120 minutes in O-IGT subjects; P < 0.05], whereas GIP secretion was higher in O-NGT than in Y-NGT subjects (GIP AUC0-120 was 4.7 ± 0.3 in Y-NGT, 6.0 ± 0.4 in O-NGT, and 4.8 ± 0.3 nmol/L∙120 minutes in O-IGT subjects; P < 0.05). CONCLUSIONS Aging is associated with an exaggerated GLP-1 secretory response. However, it was not sufficient to increase insulin first-phase release in O-IGT and overcome insulin resistance.
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Affiliation(s)
- José de Jesús Garduno-Garcia
- Diabetes Division, University of Texas Health Science Center, San Antonio, Texas
- Texas Diabetes Institute, San Antonio, Texas
| | - Amalia Gastaldelli
- Diabetes Division, University of Texas Health Science Center, San Antonio, Texas
- Institute of Clinical Physiology, Pisa, Italy
- Correspondence and Reprint Requests: Nicolas Musi, MD, Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, 15355 Lambda Drive, San Antonio, Texas 78245. E-mail: ; or Amalia Gastaldelli, PhD, Institute of Clinical Physiology, CNR, via Moruzzi, 56124 Pisa, Italy. E-mail:
| | - Ralph A DeFronzo
- Diabetes Division, University of Texas Health Science Center, San Antonio, Texas
- Texas Diabetes Institute, San Antonio, Texas
| | - Raweewan Lertwattanarak
- Diabetes Division, University of Texas Health Science Center, San Antonio, Texas
- Texas Diabetes Institute, San Antonio, Texas
| | | | - Nicolas Musi
- Diabetes Division, University of Texas Health Science Center, San Antonio, Texas
- San Antonio Geriatric Research, Education and Clinical Center, San Antonio, Texas
- Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas
- Correspondence and Reprint Requests: Nicolas Musi, MD, Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, 15355 Lambda Drive, San Antonio, Texas 78245. E-mail: ; or Amalia Gastaldelli, PhD, Institute of Clinical Physiology, CNR, via Moruzzi, 56124 Pisa, Italy. E-mail:
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Abstract
Testosterone levels are lower in men with metabolic syndrome and type 2 diabetes mellitus (T2DM) and also predict the onset of these adverse metabolic states. Body composition (body mass index, waist circumference) is an important mediator of this relationship. Sex hormone binding globulin is also inversely associated with insulin resistance and T2DM but the data regarding estrogen are inconsistent. Clinical models of androgen deficiency including Klinefelter's syndrome and androgen deprivation therapy in the treatment of advanced prostate cancer confirm the association between androgens and glucose status. Experimental manipulation of the insulin/glucose milieu and suppression of endogenous testicular function suggests the relationship between androgens and insulin sensitivity is bidirectional. Androgen therapy in men without diabetes is not able to differentiate the effect on insulin resistance from that on fat mass, in particular visceral adiposity. Similarly, several small clinical studies have examined the efficacy of exogenous testosterone in men with T2DM, however, the role of androgens, independent of body composition, in modifying insulin resistance is uncertain.
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Affiliation(s)
- Carolyn A Allan
- Prince Henry's Institute, Clayton,; Monash Health, Clayton; Department of Obstetrics and Gynaecology, Monash University, Clayton; Andrology Australia, c/o School of Public Health and Preventive Medicine, Monash University, Prahran, Australia
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Manco M, Castagneto-Gissey L, Arrighi E, Carnicelli A, Brufani C, Luciano R, Mingrone G. Insulin dynamics in young women with polycystic ovary syndrome and normal glucose tolerance across categories of body mass index. PLoS One 2014; 9:e92995. [PMID: 24705280 PMCID: PMC3976408 DOI: 10.1371/journal.pone.0092995] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 02/27/2014] [Indexed: 12/15/2022] Open
Abstract
Background Evidence favours insulin resistance and compensatory hyperinsulinemia as the predominant, perhaps primary, defects in polycystic ovary syndrome (PCOS). The aim of the present study was to evaluate insulin metabolism in young women with PCOS but normal glucose tolerance as compared with age, body mass index and insulin resistance-matched controls to answer the question whether women with PCOS hypersecrete insulin in comparison to appropriately insulin resistance-matched controls. Research Design and Methods Sixty-nine cases were divided according to their body mass index (BMI) in normal-weight (N = 29), overweight (N = 24) and obese patients (N = 16). Controls were 479 healthy women (age 16–49 y). Whole body Insulin Sensitivity (WBISI), fasting, and total insulin secretion were estimated following an oral glucose tolerance test (C-peptide deconvolution method). Results Across classes of BMI, PCOS patients had greater insulin resistance than matched controls (p<0.0001 for all the comparisons), but they showed higher fasting and total insulin secretion than their age, BMI and insulin resistance-matched peers (p<0.0001 for all the comparisons). Conclusion Women with PCOS show higher insulin resistance but also larger insulin secretion to maintain normal glucose homeostasis than age-, BMI- and insulin resistance-matched controls.
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Affiliation(s)
- Melania Manco
- Research Unit for Multi-factorial Diseases, Obesity and Diabetes, Scientific Directorate, Bambino Gesù Children Hospital, Rome, Italy
- * E-mail:
| | | | - Eugenio Arrighi
- Department of Internal Medicine, Catholic University, School of Medicine, Rome, Italy
| | - Annamaria Carnicelli
- Department of Internal Medicine, Catholic University, School of Medicine, Rome, Italy
| | - Claudia Brufani
- Research Unit for Multi-factorial Diseases, Obesity and Diabetes, Scientific Directorate, Bambino Gesù Children Hospital, Rome, Italy
| | - Rosa Luciano
- Research Unit for Multi-factorial Diseases, Obesity and Diabetes, Scientific Directorate, Bambino Gesù Children Hospital, Rome, Italy
| | - Geltrude Mingrone
- Department of Internal Medicine, Catholic University, School of Medicine, Rome, Italy
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Hoenig M, Jordan ET, Glushka J, Kley S, Patil A, Waldron M, Prestegard JH, Ferguson DC, Wu S, Olson DE. Effect of macronutrients, age, and obesity on 6- and 24-h postprandial glucose metabolism in cats. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1798-807. [PMID: 21940405 DOI: 10.1152/ajpregu.00342.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Obesity and age are risk factors for feline diabetes. This study aimed to test the hypothesis that age, long-term obesity, and dietary composition would lead to peripheral and hepatorenal insulin resistance, indicated by higher endogenous glucose production (EGP) in the fasted and postprandial state, higher blood glucose and insulin, and higher leptin, free thyroxine, and lower adiponectin concentrations. Using triple tracer-(2)H(2)O, [U-(13)C(3)] propionate, and [3,4-(13)C(2)] glucose infusion, and indirect calorimetry-we investigated carbohydrate and fat metabolic pathways in overnight-fasted neutered cats (13 young lean, 12 old lean, and 12 old obese), each fed three different diets (high protein with and without polyunsaturated fatty acids, and high carbohydrate) in a crossover design. EGP was lowest in fasted and postprandial obese cats despite peripheral insulin resistance, indicated by hyperinsulinemia. Gluconeogenesis was the most important pathway for EGP in all groups, but glycogen contributed significantly. Insulin and leptin concentrations were higher in old than in young lean cats; adiponectin was lowest in obese cats but surprisingly highest in lean old cats. Diet had little effect on metabolic parameters. We conclude that hepatorenal insulin resistance does not develop in the fasted or postprandial state, even in long-term obese cats, allowing the maintenance of euglycemia through lowering EGP. Glycogen plays a major role in EGP, especially in lean fasted cats, and in the postprandial state. Aging may predispose to insulin resistance, which is a risk factor for diabetes in cats. Mechanisms underlying the high adiponectin of healthy old lean cats need to be further explored.
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Affiliation(s)
- Margarethe Hoenig
- Department of Physiology and Pharmacology, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA.
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Dynamics of insulin action in hypertension: assessment from minimal model interpretation of intravenous glucose tolerance test data. Med Biol Eng Comput 2011; 49:831-41. [PMID: 21448693 DOI: 10.1007/s11517-011-0760-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 03/10/2011] [Indexed: 10/18/2022]
Abstract
Based on glucose kinetics minimal model (GKMM) interpretation of frequently sampled intravenous glucose tolerance test (FSIGTT), the aim was to broaden the characterization of insulin-mediated glucose disposal in hypertension by aid of a dynamic insulin sensitivity index, S(D)(I), and the related efficiency, η = S(D)(I) / S(I), of the metabolic system to convert the maximal individual response capacity, measured by S (I), into an effective insulin control on glucose. The C-peptide minimal model (CPMM) was used to interpret the role of β-cell function. Plasma glucose, insulin, and C-peptide concentrations were measured, during a 5-h FSIGTT, in eighteen normoglycemic individuals: ten hypertensive patients (H-group) and eight normotensive subjects (N-group) with no metabolic syndrome. Compared to our N-group, the H-group showed a significant (P < 0.05) reduction of both S(I) (56%) and S(D)(I) (50%), no significant change of η, a significant increase of both the first-phase β-cell responsiveness to glucose (105%) and total insulin secretion (55%), and no significant change in disposition indexes, defined as the product of insulin sensitivity (either S(I) and S(D)(I)) and β-cell responsiveness. These findings suggest that, in spite of no change of efficiency, insulin resistance in normoglycemic hypertensive patients is primarily compensated by an increase in first-phase insulin secretion to preserve glucose tolerance to intravenous glucose load.
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Uranga RM, Bruce-Keller AJ, Morrison CD, Fernandez-Kim SO, Ebenezer PJ, Zhang L, Dasuri K, Keller JN. Intersection between metabolic dysfunction, high fat diet consumption, and brain aging. J Neurochem 2010; 114:344-61. [PMID: 20477933 PMCID: PMC2910139 DOI: 10.1111/j.1471-4159.2010.06803.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Deleterious neurochemical, structural, and behavioral alterations are a seemingly unavoidable aspect of brain aging. However, the basis for these alterations, as well as the basis for the tremendous variability in regards to the degree to which these aspects are altered in aging individuals, remains to be elucidated. An increasing number of individuals regularly consume a diet high in fat, with high-fat diet consumption known to be sufficient to promote metabolic dysfunction, although the links between high-fat diet consumption and aging are only now beginning to be elucidated. In this review we discuss the potential role for age-related metabolic disturbances serving as an important basis for deleterious perturbations in the aging brain. These data not only have important implications for understanding the basis of brain aging, but also may be important to the development of therapeutic interventions which promote successful brain aging.
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Affiliation(s)
- Romina M. Uranga
- Pennington Biomedical Research Center/Louisiana State University System, Baton Rouge, LA, USA
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, Bahía Blanca, Argentina
| | | | - Christopher D. Morrison
- Pennington Biomedical Research Center/Louisiana State University System, Baton Rouge, LA, USA
| | - Sun Ok Fernandez-Kim
- Pennington Biomedical Research Center/Louisiana State University System, Baton Rouge, LA, USA
| | - Philip J. Ebenezer
- Pennington Biomedical Research Center/Louisiana State University System, Baton Rouge, LA, USA
| | - Le Zhang
- Pennington Biomedical Research Center/Louisiana State University System, Baton Rouge, LA, USA
| | - Kalavathi Dasuri
- Pennington Biomedical Research Center/Louisiana State University System, Baton Rouge, LA, USA
| | - Jeffrey N. Keller
- Pennington Biomedical Research Center/Louisiana State University System, Baton Rouge, LA, USA
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Matveyenko AV, Veldhuis JD, Butler PC. Adaptations in pulsatile insulin secretion, hepatic insulin clearance, and beta-cell mass to age-related insulin resistance in rats. Am J Physiol Endocrinol Metab 2008; 295:E832-41. [PMID: 18664594 PMCID: PMC2575907 DOI: 10.1152/ajpendo.90451.2008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In health insulin is secreted in discrete insulin secretory bursts from pancreatic beta-cells, collectively referred to as beta-cell mass. We sought to establish the relationship between beta-cell mass, insulin secretory-burst mass, and hepatic insulin clearance over a range of age-related insulin sensitivity in adult rats. To address this, we used a novel rat model with chronically implanted portal vein catheters in which we recently established the parameters to permit deconvolution of portal vein insulin concentration profiles to measure insulin secretion and resolve its pulsatile components. In the present study, we examined total and pulsatile insulin secretion, insulin sensitivity, hepatic insulin clearance, and beta-cell mass in 35 rats aged 2-12 mo. With aging, insulin sensitivity declined, but euglycemia was sustained by an adaptive increase in fasting and glucose-stimulated insulin secretion through the mechanism of a selective augmentation of insulin pulse mass. The latter was attributable to a closely related increase in beta-cell mass (r=0.8, P<0.001). Hepatic insulin clearance increased with increasing portal vein insulin pulse amplitude, damping the delivery of insulin in the systemic circulation. In consequence, the curvilinear relationship previously reported between insulin secretion and insulin sensitivity was extended to both insulin pulse mass and beta-cell mass vs. insulin sensitivity. These data support a central role of adaptive changes in beta-cell mass to permit appropriate insulin secretion in the setting of decreasing insulin sensitivity in the aging animal. They emphasize the cooperative role of pancreatic beta-cells and the liver in regulating the secretion and delivery of insulin to the systemic circulation.
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Affiliation(s)
- Aleksey V Matveyenko
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA.
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