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Seckiner S, Bas M, Simsir IY, Ozgur S, Akcay Y, Aslan CG, Kucukerdonmez O, Cetinkalp S. Effects of Dietary Carbohydrate Concentration and Glycemic Index on Blood Glucose Variability and Free Fatty Acids in Individuals with Type 1 Diabetes. Nutrients 2024; 16:1383. [PMID: 38732629 PMCID: PMC11085728 DOI: 10.3390/nu16091383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/08/2024] [Accepted: 04/08/2024] [Indexed: 05/13/2024] Open
Abstract
Monitoring glycemic control status is the cornerstone of diabetes management. This study aimed to reveal whether moderate-carbohydrate (CHO) diets increase the risk of free fatty acid (FFA) levels, and it presents the short-term effects of four different diet models on blood sugar, glycemic variability (GV), and FFA levels. This crossover study included 17 patients with type 1 diabetes mellitus to identify the effects of four diets with different CHO contents and glycemic index (GI) on GV and plasma FFA levels. Diet 1 (D1) contained 40% CHO with a low GI, diet 2 (D2) contained 40% CHO with a high GI, diet 3 (D3) contained 60% CHO with a low GI, and diet 4 (D4) contained 60% CHO with a high GI. Interventions were performed with sensor monitoring in four-day periods and completed in four weeks. No statistical difference was observed among the groups in terms of blood glucose area under the curve (p = 0.78), mean blood glucose levels (p = 0.28), GV (p = 0.59), and time in range (p = 0.567). FFA and total triglyceride levels were higher in the D1 group (p < 0.014 and p = 0.002, respectively). Different diets may increase the risk of cardiovascular diseases by affecting GI, FFA, and blood glucose levels.
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Affiliation(s)
- Selda Seckiner
- Department of Nutrition and Dietetics, Faculty of Health Sciences, İstanbul Beykent University, Istanbul 34520, Turkey
- Institute of Health Sciences, Acibadem Mehmet Ali Aydınlar University, Istanbul 34450, Turkey
| | - Murat Bas
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Acibadem Mehmet Ali Aydınlar University, Istanbul 34450, Turkey;
| | - Ilgin Yildirim Simsir
- Division of Endocrinology and Metabolism Disorders, Department of Internal Medicine, Faculty of Medicine, Ege University, Izmir 35100, Turkey; (I.Y.S.); (S.C.)
| | - Su Ozgur
- Department of Biostatistics and Medical Informatics, Faculty of Medicine, Ege University, Izmir 35100, Turkey;
| | - Yasemin Akcay
- Department of Medical Biochemistry, Faculty of Medicine, Ege University, Izmir 35100, Turkey;
| | - Cigdem Gozde Aslan
- Department of Medical Biochemistry, Faculty of Medicine, Biruni University, Istanbul 34010, Turkey;
| | - Ozge Kucukerdonmez
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Ege University, Izmir 35100, Turkey;
| | - Sevki Cetinkalp
- Division of Endocrinology and Metabolism Disorders, Department of Internal Medicine, Faculty of Medicine, Ege University, Izmir 35100, Turkey; (I.Y.S.); (S.C.)
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2
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Scoditti E, Sabatini S, Carli F, Gastaldelli A. Hepatic glucose metabolism in the steatotic liver. Nat Rev Gastroenterol Hepatol 2024; 21:319-334. [PMID: 38308003 DOI: 10.1038/s41575-023-00888-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/13/2023] [Indexed: 02/04/2024]
Abstract
The liver is central in regulating glucose homeostasis, being the major contributor to endogenous glucose production and the greatest reserve of glucose as glycogen. It is both a target and regulator of the action of glucoregulatory hormones. Hepatic metabolic functions are altered in and contribute to the highly prevalent steatotic liver disease (SLD), including metabolic dysfunction-associated SLD (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). In this Review, we describe the dysregulation of hepatic glucose metabolism in MASLD and MASH and associated metabolic comorbidities, and how advances in techniques and models for the assessment of hepatic glucose fluxes in vivo have led to the identification of the mechanisms related to the alterations in glucose metabolism in MASLD and comorbidities. These fluxes can ultimately increase hepatic glucose production concomitantly with fat accumulation and alterations in the secretion and action of glucoregulatory hormones. No pharmacological treatment has yet been approved for MASLD or MASH, but some antihyperglycaemic drugs approved for treating type 2 diabetes have shown positive effects on hepatic glucose metabolism and hepatosteatosis. A deep understanding of how MASLD affects glucose metabolic fluxes and glucoregulatory hormones might assist in the early identification of at-risk individuals and the use or development of targeted therapies.
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Affiliation(s)
- Egeria Scoditti
- Institute of Clinical Physiology, National Research Council, Lecce, Italy
| | - Silvia Sabatini
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Fabrizia Carli
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Amalia Gastaldelli
- Institute of Clinical Physiology, National Research Council, Pisa, Italy.
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3
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Kitamoto T, Accili D. Unraveling the mysteries of hepatic insulin signaling: deconvoluting the nuclear targets of insulin. Endocr J 2023; 70:851-866. [PMID: 37245960 DOI: 10.1507/endocrj.ej23-0150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
Over 100 years have passed since insulin was first administered to a diabetic patient. Since then great strides have been made in diabetes research. It has determined where insulin is secreted from, which organs it acts on, how it is transferred into the cell and is delivered to the nucleus, how it orchestrates the expression pattern of the genes, and how it works with each organ to maintain systemic metabolism. Any breakdown in this system leads to diabetes. Thanks to the numerous researchers who have dedicated their lives to cure diabetes, we now know that there are three major organs where insulin acts to maintain glucose/lipid metabolism: the liver, muscles, and fat. The failure of insulin action on these organs, such as insulin resistance, result in hyperglycemia and/or dyslipidemia. The primary trigger of this condition and its association among these tissues still remain to be uncovered. Among the major organs, the liver finely tunes the glucose/lipid metabolism to maintain metabolic flexibility, and plays a crucial role in glucose/lipid abnormality due to insulin resistance. Insulin resistance disrupts this tuning, and selective insulin resistance arises. The glucose metabolism loses its sensitivity to insulin, while the lipid metabolism maintains it. The clarification of its mechanism is warranted to reverse the metabolic abnormalities due to insulin resistance. This review will provide a brief historical review for the progress of the pathophysiology of diabetes since the discovery of insulin, followed by a review of the current research clarifying our understanding of selective insulin resistance.
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Affiliation(s)
- Takumi Kitamoto
- Department of Diabetes, Metabolism and Endocrinology, Chiba University Hospital, Chiba 260-8670, Japan
| | - Domenico Accili
- Department of Medicine and Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons of Columbia University, New York, NY 10032 USA
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4
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Guilherme A, Rowland LA, Wang H, Czech MP. The adipocyte supersystem of insulin and cAMP signaling. Trends Cell Biol 2023; 33:340-354. [PMID: 35989245 PMCID: PMC10339226 DOI: 10.1016/j.tcb.2022.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 01/28/2023]
Abstract
Adipose tissue signals to brain, liver, and muscles to control whole body metabolism through secreted lipid and protein factors as well as neurotransmission, but the mechanisms involved are incompletely understood. Adipocytes sequester triglyceride (TG) in fed conditions stimulated by insulin, while in fasting catecholamines trigger TG hydrolysis, releasing glycerol and fatty acids (FAs). These antagonistic hormone actions result in part from insulin's ability to inhibit cAMP levels generated through such G-protein-coupled receptors as catecholamine-activated β-adrenergic receptors. Consistent with these antagonistic signaling modes, acute actions of catecholamines cause insulin resistance. Yet, paradoxically, chronically activating adipocytes by catecholamines cause increased glucose tolerance, as does insulin. Recent results have helped to unravel this conundrum by revealing enhanced complexities of these hormones' signaling networks, including identification of unexpected common signaling nodes between these canonically antagonistic hormones.
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Affiliation(s)
- Adilson Guilherme
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.
| | - Leslie A Rowland
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Hui Wang
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Michael P Czech
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.
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5
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Kraft G, Coate KC, Smith M, Farmer B, Scott M, Hastings J, Cherrington AD, Edgerton DS. Profound Sensitivity of the Liver to the Direct Effect of Insulin Allows Peripheral Insulin Delivery to Normalize Hepatic but Not Muscle Glucose Uptake in the Healthy Dog. Diabetes 2023; 72:196-209. [PMID: 36280227 PMCID: PMC9871195 DOI: 10.2337/db22-0471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/18/2022] [Indexed: 01/28/2023]
Abstract
Endogenous insulin secretion is a key regulator of postprandial hepatic glucose metabolism, but this process is dysregulated in diabetes. Subcutaneous insulin delivery alters normal insulin distribution, causing relative hepatic insulin deficiency and peripheral hyperinsulinemia, a major risk factor for metabolic disease. Our aim was to determine whether insulin's direct effect on the liver is preeminent even when insulin is given into a peripheral vein. Postprandial-like conditions were created (hyperinsulinemia, hyperglycemia, and a positive portal vein to arterial glucose gradient) in healthy dogs. Peripheral (leg vein) insulin infusion elevated arterial and hepatic levels 8.0-fold and 2.8-fold, respectively. In one group, insulin's full effects were allowed. In another, insulin's indirect hepatic effects were blocked with the infusion of triglyceride, glucagon, and inhibitors of brain insulin action (intracerebroventricular) to prevent decreases in plasma free fatty acids and glucagon, while blocking increased hypothalamic insulin signaling. Despite peripheral insulin delivery the liver retained its full ability to store glucose, even when insulin's peripheral effects were blocked, whereas muscle glucose uptake markedly increased, creating an aberrant distribution of glucose disposal between liver and muscle. Thus, the healthy liver's striking sensitivity to direct insulin action can overcome the effect of relative hepatic insulin deficiency, whereas excess insulin in the periphery produces metabolic abnormalities in nonhepatic tissues.
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Affiliation(s)
| | | | | | | | | | | | | | - Dale S. Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
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Sasaki N, Maeda R, Ozono R, Yoshimura K, Nakano Y, Higashi Y. Early-Phase Changes in Serum Free Fatty Acid Levels After Glucose Intake Are Associated With Type 2 Diabetes Incidence: The Hiroshima Study on Glucose Metabolism and Cardiovascular Diseases. Diabetes Care 2022; 45:2309-2315. [PMID: 35944240 DOI: 10.2337/dc21-2554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 06/27/2022] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Experimental studies suggest that excess serum free fatty acid (FFA) levels result in impaired glucose metabolism. This study investigated the relationship between changes in serum FFA levels after glucose intake and type 2 diabetes risk. RESEARCH DESIGN AND METHODS This observational study included 6,800 individuals without diabetes who underwent a 75-g oral glucose tolerance test. Serum FFA levels were measured before and 30 and 60 min after glucose intake. The percentages of changes in serum FFA levels from 0 to 30 and from 30 to 60 min were compared, and a low rate of change in FFA levels was determined using the receiver operating characteristic curve analysis. RESULTS Over a mean 5.3-year follow-up period, 485 participants developed type 2 diabetes. After adjusting for plasma glucose levels and indices of insulin resistance and β-cell function, low rates of change in FFA levels at 0-30 min (adjusted odds ratio [aOR] 1.91; 95% CI 1.54-2.37) and 30-60 min (aOR 1.48; 95% CI 1.15-1.90) were associated with the incidence of type 2 diabetes. Stratified analysis revealed that the low rate of change in FFA levels at 30-60 min (aOR 1.97; 95% CI 1.05-3.69) was associated with the incidence of type 2 diabetes even in participants with normal fasting glucose levels or glucose tolerance. CONCLUSIONS Changes in serum FFA levels within the 1st h after glucose intake could be a primary predictor of type 2 diabetes. This change may occur prior to the onset of impaired glucose metabolism.
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Affiliation(s)
- Nobuo Sasaki
- Health Management and Promotion Center, Hiroshima Atomic Bomb Casualty Council, Hiroshima, Japan
| | - Ryo Maeda
- Health Management and Promotion Center, Hiroshima Atomic Bomb Casualty Council, Hiroshima, Japan
| | - Ryoji Ozono
- Department of General Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Kenichi Yoshimura
- Department of Biostatistics, Medical Center for Translational and Clinical Research, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Yukiko Nakano
- Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Yukihito Higashi
- Department of Cardiovascular Regeneration and Medicine, Research Institute for Radiation Biology and Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
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7
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Granade ME, Hargett SR, Lank DS, Lemke MC, Luse MA, Isakson BE, Bochkis IM, Linden J, Harris TE. Feeding desensitizes A1 adenosine receptors in adipose through FOXO1-mediated transcriptional regulation. Mol Metab 2022; 63:101543. [PMID: 35811051 PMCID: PMC9304768 DOI: 10.1016/j.molmet.2022.101543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/24/2022] [Accepted: 07/04/2022] [Indexed: 12/03/2022] Open
Abstract
OBJECTIVE Adipose tissue is a critical regulator of energy balance that must rapidly shift its metabolism between fasting and feeding to maintain homeostasis. Adenosine has been characterized as an important regulator of adipocyte metabolism primarily through its actions on A1 adenosine receptors (A1R). We sought to understand the role A1R plays specifically in adipocytes during fasting and feeding to regulate glucose and lipid metabolism. METHODS We used Adora1 floxed mice with an inducible, adiponectin-Cre to generate FAdora1-/- mice, where F designates a fat-specific deletion of A1R. We used these FAdora1-/- mice along with specific agonists and antagonists of A1R to investigate changes in adenosine signaling within adipocytes between the fasted and fed state. RESULTS We found that the adipose tissue response to adenosine is not static, but changes dynamically according to nutrient conditions through the insulin-Akt-FOXO1 axis. We show that under fasted conditions, FAdora1-/- mice had impairments in the suppression of lipolysis by insulin on normal chow and impaired glucose tolerance on high-fat diet. FAdora1-/- mice also exhibited a higher lipolytic response to isoproterenol than WT controls when fasted, however this difference was lost after a 4-hour refeeding period. We demonstrate that FOXO1 binds to the A1R promoter, and refeeding leads to a rapid downregulation of A1R transcript and desensitization of adipocytes to A1R agonism. Obesity also desensitizes adipocyte A1R, and this is accompanied by a disruption of cyclical changes in A1R transcription between fasting and refeeding. CONCLUSIONS We propose that FOXO1 drives high A1R expression under fasted conditions to limit excess lipolysis during stress and augment insulin action upon feeding. Subsequent downregulation of A1R under fed conditions leads to desensitization of these receptors in adipose tissue. This regulation of A1R may facilitate reentrance into the catabolic state upon fasting.
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Affiliation(s)
- Mitchell E Granade
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Stefan R Hargett
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Daniel S Lank
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Michael C Lemke
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Melissa A Luse
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA, USA
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA, USA
| | - Irina M Bochkis
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Joel Linden
- Department of Medicine, Center for Immunity, Inflammation and Regenerative Medicine, University of Virginia, Charlottesville, VA, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.
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8
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Metabolic Action of Metformin. Pharmaceuticals (Basel) 2022; 15:ph15070810. [PMID: 35890109 PMCID: PMC9317619 DOI: 10.3390/ph15070810] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/14/2022] [Accepted: 06/26/2022] [Indexed: 12/12/2022] Open
Abstract
Metformin, a cheap and safe biguanide derivative, due to its ability to influence metabolism, is widely used as a first-line drug for type 2 diabetes (T2DM) treatment. Therefore, the aim of this review was to present the updated biochemical and molecular effects exerted by the drug. It has been well explored that metformin suppresses hepatic glucose production in both AMPK-independent and AMPK-dependent manners. Substantial scientific evidence also revealed that its action is related to decreased secretion of lipids from intestinal epithelial cells, as well as strengthened oxidation of fatty acids in adipose tissue and muscles. It was recognized that metformin’s supra-therapeutic doses suppress mitochondrial respiration in intestinal epithelial cells, whereas its therapeutic doses elevate cellular respiration in the liver. The drug is also suggested to improve systemic insulin sensitivity as a result of alteration in gut microbiota composition, maintenance of intestinal barrier integrity, and alleviation of low-grade inflammation.
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9
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Gasser E, Sancar G, Downes M, Evans RM. Metabolic Messengers: fibroblast growth factor 1. Nat Metab 2022; 4:663-671. [PMID: 35681108 PMCID: PMC9624216 DOI: 10.1038/s42255-022-00580-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/15/2022] [Accepted: 04/27/2022] [Indexed: 11/09/2022]
Abstract
While fibroblast growth factor (FGF) 1 is expressed in multiple tissues, only adipose-derived and brain FGF1 have been implicated in the regulation of metabolism. Adipose FGF1 production is upregulated in response to dietary stress and is essential for adipose tissue plasticity in these conditions. Similarly, in the brain, FGF1 secretion into the ventricular space and the adjacent parenchyma is increased after a hypercaloric challenge induced by either feeding or glucose infusion. Potent anorexigenic properties have been ascribed to both peripheral and centrally injected FGF1. The ability of recombinant FGF1 and variants with reduced mitogenicity to lower glucose, suppress adipose lipolysis and promote insulin sensitization elevates their potential as candidates in the treatment of type 2 diabetes mellitus and associated comorbidities. Here, we provide an overview of the known metabolic functions of endogenous FGF1 and discuss its therapeutic potential, distinguishing between peripherally or centrally administered FGF1.
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Affiliation(s)
- Emanuel Gasser
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Gencer Sancar
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Michael Downes
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA.
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10
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McKenzie BA, Chen FL, Gruen ME, Olby NJ. Canine Geriatric Syndrome: A Framework for Advancing Research in Veterinary Geroscience. Front Vet Sci 2022; 9:853743. [PMID: 35529834 PMCID: PMC9069128 DOI: 10.3389/fvets.2022.853743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 03/23/2022] [Indexed: 12/26/2022] Open
Abstract
Biological aging is the single most important risk factor for disease, disability, and ultimately death in geriatric dogs. The effects of aging in companion dogs also impose significant financial and psychological burdens on their human caregivers. The underlying physiologic processes of canine aging may be occult, or early signs of aging may be ignored because of the misconception that biological aging is natural and therefore inevitable. The ability to detect, quantify, and mitigate the deleterious processes of canine aging would greatly enhance veterinary preventative medicine and animal welfare. In this paper we propose a new conceptual framework for aging in dogs, the Canine Geriatric Syndrome (CGS). CGS consists of the multiple, interrelated physical, functional, behavioral, and metabolic changes that characterize canine aging as well as the resulting clinical manifestations, including frailty, diminished quality of life, and age-associated disease. We also identify potential key components of a CGS assessment tool, a clinical instrument that would enable veterinarians to diagnose CGS and would facilitate the development and testing of interventions to prolong healthspan and lifespan in dogs by directly targeting the biological mechanisms of aging. There are many gaps in our knowledge of the mechanisms and phenotype of aging in dogs that must be bridged before a CGS assessment tool can be deployed. The conceptual framework of CGS should facilitate identifying these gaps and should stimulate research to better characterize the processes and effects of aging in dogs and to identify the most promising preventative strategies to target these.
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Affiliation(s)
| | - Frances L. Chen
- Cellular Longevity Inc., dba Loyal, San Francisco, CA, United States
| | - Margaret E. Gruen
- College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States
| | - Natasha J. Olby
- College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States
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Gao D, Jiao J, Wang Z, Huang X, Ni X, Fang S, Zhou Q, Zhu X, Sun L, Yang Z, Yuan H. The roles of cell-cell and organ-organ crosstalk in the type 2 diabetes mellitus associated inflammatory microenvironment. Cytokine Growth Factor Rev 2022; 66:15-25. [PMID: 35459618 DOI: 10.1016/j.cytogfr.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 11/30/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a classic metaflammatory disease, and the inflammatory states of the pancreatic islet and insulin target organs have been well confirmed. However, abundant evidence demonstrates that there are countless connections between these organs in the presence of a low degree of inflammation. In this review, we focus on cell-cell crosstalk among local cells in the islet and organ-organ crosstalk among insulin-related organs. In contrast to that in acute inflammation, macrophages are the dominant immune cells causing inflammation in the islets and insulin target organs in T2DM. In the inflammatory microenvironment (IME) of the islet, cell-cell crosstalk involving local macrophage polarization and proinflammatory cytokine production impair insulin secretion by β-cells. Furthermore, organ-organ crosstalk, including the gut-brain-pancreas axis and interactions among insulin-related organs during inflammation, reduces insulin sensitivity and induces endocrine dysfunction. Therefore, this crosstalk ultimately results in a cascade leading to β-cell dysfunction. These findings could have broad implications for therapies aimed at treating T2DM.
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Affiliation(s)
- Danni Gao
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China; Peking University Fifth School of Clinical Medicine, Beijing 100730, PR China
| | - Juan Jiao
- Department of Clinical Laboratory, the Seventh Medical Centre of Chinese PLA General Hospital, Beijing 100700, PR China
| | - Zhaoping Wang
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China
| | - Xiuqing Huang
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China
| | - Xiaolin Ni
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China
| | - Sihang Fang
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China
| | - Qi Zhou
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China
| | - Xiaoquan Zhu
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China
| | - Liang Sun
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China
| | - Ze Yang
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China
| | - Huiping Yuan
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing 100730, PR China; Peking University Fifth School of Clinical Medicine, Beijing 100730, PR China.
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12
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Sarbazi-Golezari A, Haghdoost-Yazdi H. Chronic and progressive dopaminergic neuronal death in substantia nigra associates with a decrease in serum levels of glucose and free fatty acids, the role of interlokin-1 beta. Metab Brain Dis 2022; 37:373-381. [PMID: 34767157 DOI: 10.1007/s11011-021-00868-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 10/31/2021] [Indexed: 11/24/2022]
Abstract
Human studies indicate that Parkinson's disease (PD) associates with disruption in metabolism of glucose and free fatty acids (FFA). Studies have shown that interlukin-1beta (IL-1β) causes hypoglycemia through insulin- independent mechanisms. Here, we investigated association between dopaminergic neuronal death, as the main pathophysiological mechanism underlying PD, and serum levels of glucose, FFA and IL-1β in 6-hydroxydopamine (6-OHDA) animal model of PD. Neurotoxin of 6-OHDA was injected into medial forebrain bundle and multiple behavioral testes were carried out during eight weeks thereafter. Blood was collected before the toxin and in second and eight weeks thereafter. Then, brain of the animals was perfused to assess survival of dopaminergic (DAergic) neurons in substantia nigra by tyrosine hydroxylase (TH) immunohistochemistry. Glucose, FFA and IL-1β levels were determined using calorimetric method and specific ELISA kits. In compare to control, 6-OHDA- treated rats had less glucose and FFA levels in the eight week and higher IL-1β level in the both second and eight weeks. Based on severity of behavioral symptoms, 6-OHDA- treated rats were divided into two subgroups of severe and mild. Number of TH- positive cells in these subgroups was 83 and 45% less than that in control. Also, both subgroups showed less weight gain, lower glucose and FFA and higher IL-1β in eight week. Our data indicate that moderate to severe progressive DAergic neuronal death in substantia nigra associates with a decrease in serum levels of glucose and FFA. Increase in IL-1β production following neuronal death possibly mediated this decrease.
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Affiliation(s)
- Ali Sarbazi-Golezari
- Cellular and Molecular Research Center, Research Institute for Prevention of Non- Communicable Disease, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Hashem Haghdoost-Yazdi
- Cellular and Molecular Research Center, Research Institute for Prevention of Non- Communicable Disease, Qazvin University of Medical Sciences, Qazvin, Iran.
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13
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Sancar G, Liu S, Gasser E, Alvarez JG, Moutos C, Kim K, van Zutphen T, Wang Y, Huddy TF, Ross B, Dai Y, Zepeda D, Collins B, Tilley E, Kolar MJ, Yu RT, Atkins AR, van Dijk TH, Saghatelian A, Jonker JW, Downes M, Evans RM. FGF1 and insulin control lipolysis by convergent pathways. Cell Metab 2022; 34:171-183.e6. [PMID: 34986332 PMCID: PMC8863067 DOI: 10.1016/j.cmet.2021.12.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/08/2021] [Accepted: 12/06/2021] [Indexed: 01/07/2023]
Abstract
Inexorable increases in insulin resistance, lipolysis, and hepatic glucose production (HGP) are hallmarks of type 2 diabetes. Previously, we showed that peripheral delivery of exogenous fibroblast growth factor 1 (FGF1) has robust anti-diabetic effects mediated by the adipose FGF receptor (FGFR) 1. However, its mechanism of action is not known. Here, we report that FGF1 acutely lowers HGP by suppressing adipose lipolysis. On a molecular level, FGF1 inhibits the cAMP-protein kinase A axis by activating phosphodiesterase 4D (PDE4D), which separates it mechanistically from the inhibitory actions of insulin via PDE3B. We identify Ser44 as an FGF1-induced regulatory phosphorylation site in PDE4D that is modulated by the feed-fast cycle. These findings establish the FGF1/PDE4 pathway as an alternate regulator of the adipose-HGP axis and identify FGF1 as an unrecognized regulator of fatty acid homeostasis.
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Affiliation(s)
- Gencer Sancar
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Sihao Liu
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Emanuel Gasser
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jacqueline G Alvarez
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Christopher Moutos
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Kyeongkyu Kim
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Tim van Zutphen
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 GZ, Groningen, the Netherlands
| | - Yuhao Wang
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Timothy F Huddy
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Brittany Ross
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Yang Dai
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - David Zepeda
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Brett Collins
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Emma Tilley
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Matthew J Kolar
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Ruth T Yu
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Annette R Atkins
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Theo H van Dijk
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 GZ, Groningen, the Netherlands
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Johan W Jonker
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 GZ, Groningen, the Netherlands
| | - Michael Downes
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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14
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Lee SH, Park SY, Choi CS. Insulin Resistance: From Mechanisms to Therapeutic Strategies. Diabetes Metab J 2022; 46:15-37. [PMID: 34965646 PMCID: PMC8831809 DOI: 10.4093/dmj.2021.0280] [Citation(s) in RCA: 175] [Impact Index Per Article: 87.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/27/2021] [Indexed: 11/12/2022] Open
Abstract
Insulin resistance is the pivotal pathogenic component of many metabolic diseases, including type 2 diabetes mellitus, and is defined as a state of reduced responsiveness of insulin-targeting tissues to physiological levels of insulin. Although the underlying mechanism of insulin resistance is not fully understood, several credible theories have been proposed. In this review, we summarize the functions of insulin in glucose metabolism in typical metabolic tissues and describe the mechanisms proposed to underlie insulin resistance, that is, ectopic lipid accumulation in liver and skeletal muscle, endoplasmic reticulum stress, and inflammation. In addition, we suggest potential therapeutic strategies for addressing insulin resistance.
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Affiliation(s)
- Shin-Hae Lee
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Korea
| | - Shi-Young Park
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Korea
| | - Cheol Soo Choi
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Korea
- Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Korea
- Division of Molecular Medicine, Gachon University College of Medicine, Incheon, Korea
- Corresponding author: Cheol Soo Choi https://orcid.org/0000-0001-9627-058X Division of Molecular Medicine, Gachon University College of Medicine, 21 Namdongdaero 774beon-gil, Namdong-gu, Incheon 21565, Korea E-mail:
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15
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The aetiology and molecular landscape of insulin resistance. Nat Rev Mol Cell Biol 2021; 22:751-771. [PMID: 34285405 DOI: 10.1038/s41580-021-00390-6] [Citation(s) in RCA: 201] [Impact Index Per Article: 67.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2021] [Indexed: 02/07/2023]
Abstract
Insulin resistance, defined as a defect in insulin-mediated control of glucose metabolism in tissues - prominently in muscle, fat and liver - is one of the earliest manifestations of a constellation of human diseases that includes type 2 diabetes and cardiovascular disease. These diseases are typically associated with intertwined metabolic abnormalities, including obesity, hyperinsulinaemia, hyperglycaemia and hyperlipidaemia. Insulin resistance is caused by a combination of genetic and environmental factors. Recent genetic and biochemical studies suggest a key role for adipose tissue in the development of insulin resistance, potentially by releasing lipids and other circulating factors that promote insulin resistance in other organs. These extracellular factors perturb the intracellular concentration of a range of intermediates, including ceramide and other lipids, leading to defects in responsiveness of cells to insulin. Such intermediates may cause insulin resistance by inhibiting one or more of the proximal components in the signalling cascade downstream of insulin (insulin receptor, insulin receptor substrate (IRS) proteins or AKT). However, there is now evidence to support the view that insulin resistance is a heterogeneous disorder that may variably arise in a range of metabolic tissues and that the mechanism for this effect likely involves a unified insulin resistance pathway that affects a distal step in the insulin action pathway that is more closely linked to the terminal biological response. Identifying these targets is of major importance, as it will reveal potential new targets for treatments of diseases associated with insulin resistance.
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16
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Abstract
The reactions of the tricarboxylic acid (TCA) cycle allow the controlled combustion of fat and carbohydrate. In principle, TCA cycle intermediates are regenerated on every turn and can facilitate the oxidation of an infinite number of nutrient molecules. However, TCA cycle intermediates can be lost to cataplerotic pathways that provide precursors for biosynthesis, and they must be replaced by anaplerotic pathways that regenerate these intermediates. Together, anaplerosis and cataplerosis help regulate rates of biosynthesis by dictating precursor supply, and they play underappreciated roles in catabolism and cellular energy status. They facilitate recycling pathways and nitrogen trafficking necessary for catabolism, and they influence redox state and oxidative capacity by altering TCA cycle intermediate concentrations. These functions vary widely by tissue and play emerging roles in disease. This article reviews the roles of anaplerosis and cataplerosis in various tissues and discusses how they alter carbon transitions, and highlights their contribution to mechanisms of disease. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Melissa Inigo
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA;
| | - Stanisław Deja
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; .,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Shawn C Burgess
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; .,Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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17
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Mechanisms and disease consequences of nonalcoholic fatty liver disease. Cell 2021; 184:2537-2564. [PMID: 33989548 DOI: 10.1016/j.cell.2021.04.015] [Citation(s) in RCA: 758] [Impact Index Per Article: 252.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/21/2021] [Accepted: 04/09/2021] [Indexed: 02/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the leading chronic liver disease worldwide. Its more advanced subtype, nonalcoholic steatohepatitis (NASH), connotes progressive liver injury that can lead to cirrhosis and hepatocellular carcinoma. Here we provide an in-depth discussion of the underlying pathogenetic mechanisms that lead to progressive liver injury, including the metabolic origins of NAFLD, the effect of NAFLD on hepatic glucose and lipid metabolism, bile acid toxicity, macrophage dysfunction, and hepatic stellate cell activation, and consider the role of genetic, epigenetic, and environmental factors that promote fibrosis progression and risk of hepatocellular carcinoma in NASH.
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18
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Lewis GF, Carpentier AC, Pereira S, Hahn M, Giacca A. Direct and indirect control of hepatic glucose production by insulin. Cell Metab 2021; 33:709-720. [PMID: 33765416 DOI: 10.1016/j.cmet.2021.03.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/23/2021] [Accepted: 03/05/2021] [Indexed: 01/08/2023]
Abstract
There is general agreement that the acute suppression of hepatic glucose production by insulin is mediated by both a direct and an indirect effect on the liver. There is, however, no consensus regarding the relative magnitude of these effects under physiological conditions. Extensive research over the past three decades in humans and animal models has provided discordant results between these two modes of insulin action. Here, we review the field to make the case that physiologically direct hepatic insulin action dominates acute suppression of glucose production, but that there is also a delayed, second order regulation of this process via extrahepatic effects. We further provide our views regarding the timing, dominance, and physiological relevance of these effects and discuss novel concepts regarding insulin regulation of adipose tissue fatty acid metabolism and central nervous system (CNS) signaling to the liver, as regulators of insulin's extrahepatic effects on glucose production.
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Affiliation(s)
- Gary F Lewis
- Departments of Medicine and Physiology, University of Toronto, Toronto, ON, Canada; Banting & Best Diabetes Centre, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
| | - Andre C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Sandra Pereira
- Centre for Addiction and Mental Health and Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Margaret Hahn
- Banting & Best Diabetes Centre, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada; Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Adria Giacca
- Departments of Medicine and Physiology, University of Toronto, Toronto, ON, Canada; Banting & Best Diabetes Centre, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
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19
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Dokukina IV, Yamashev MV, Samarina EA, Tilinova OM, Grachev EA. Calcium-dependent insulin resistance in hepatocytes: mathematical model. J Theor Biol 2021; 522:110684. [PMID: 33794287 DOI: 10.1016/j.jtbi.2021.110684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 03/07/2021] [Accepted: 03/15/2021] [Indexed: 02/07/2023]
Abstract
Hepatocyte insulin resistance is one of the early factors of developing type II diabetes. If insulin resistance is treated early, type II diabetes could be prevented. In recent years, scientists have been conducting extensive research on the underlying issues on a cellular and molecular level. It was found that the modulation of IP3-receptors, the mitochondrial ability to form the mitochondria-associated membranes (MAMs) and the endoplasmic reticulum stress during Ca2+ signaling play a key role in hepatocyte being able to maintain euglycemia and provide metabolic flexibility. However, researchers cannot agree on what factor is the key one in resulting in insulin resistance. In this work, we propose a mathematical model of Ca2+ signaling. We included in the model all the major contributors of a proper Ca2+ signaling during both the fasting and the postprandial state. Our modeling results are in good agreement with available experimental data. The analysis of modeling results suggests that MAMs dysfunction alone cannot result in abnormal Ca2+ signaling and the wrong modulation of IP3-receptors is a more definite reason. However, both the MAMs dysfunction and the IP3 signaling dysregulation combined can lead to a robust Ca2+ signal and improper glucose release. In addition, our model results suggest a strong dependence of Ca2+ oscillations pattern on morphological characteristics of the ER and the mitochondria.
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Affiliation(s)
- Irina V Dokukina
- Sarov Physical and Technical Institute, National Research Nuclear University MEPhI, Sarov, Russian Federation.
| | | | - Ekaterina A Samarina
- Sarov Physical and Technical Institute, National Research Nuclear University MEPhI, Sarov, Russian Federation
| | - Oksana M Tilinova
- Sarov Physical and Technical Institute, National Research Nuclear University MEPhI, Sarov, Russian Federation
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20
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Rawlinson S, Andrews ZB. Hypothalamic insulin signalling as a nexus regulating mood and metabolism. J Neuroendocrinol 2021; 33:e12939. [PMID: 33634518 DOI: 10.1111/jne.12939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 01/23/2023]
Abstract
Insulin has long been known as a metabolic hormone critical in the treatment of diabetes for its peripheral effects on blood glucose. However, in the last 50 years, insulin has entered the realm of neuroendocrinology and many studies have described its function on insulin receptors in the brain in relation to both metabolic and mood disorders. Indeed, rodent models of impaired insulin signalling show signs of dysregulated energy and glucose homeostasis, as well as anxiety-like and depressive behaviours. Importantly, many metabolic diseases such as obesity and diabetes increase the risk of developing mood disorders; however, the brain mechanisms underlying the connection between metabolism and mood remain unresolved. We present the current literature on the importance of the insulin receptor with respect to regulating glucose and energy homeostasis and mood-related behaviours. Specifically, we hypothesise that the insulin receptor in the hypothalamus, classically known as the homeostatic centre of the brain, plays a causal role in linking metabolic and behavioural effects of insulin signalling. In this review, we discuss insulin signalling in the hypothalamus as a critical point of neural integration controlling metabolism and mood.
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Affiliation(s)
- Sasha Rawlinson
- Department of Physiology, Monash Biomedicine Discovery Institute Monash University, Clayton, VIC, Australia
| | - Zane B Andrews
- Department of Physiology, Monash Biomedicine Discovery Institute Monash University, Clayton, VIC, Australia
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21
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LaMoia TE, Shulman GI. Cellular and Molecular Mechanisms of Metformin Action. Endocr Rev 2021; 42:77-96. [PMID: 32897388 PMCID: PMC7846086 DOI: 10.1210/endrev/bnaa023] [Citation(s) in RCA: 273] [Impact Index Per Article: 91.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/04/2020] [Indexed: 02/07/2023]
Abstract
Metformin is a first-line therapy for the treatment of type 2 diabetes, due to its robust glucose-lowering effects, well-established safety profile, and relatively low cost. While metformin has been shown to have pleotropic effects on glucose metabolism, there is a general consensus that the major glucose-lowering effect in patients with type 2 diabetes is mostly mediated through inhibition of hepatic gluconeogenesis. However, despite decades of research, the mechanism by which metformin inhibits this process is still highly debated. A key reason for these discrepant effects is likely due to the inconsistency in dosage of metformin across studies. Widely studied mechanisms of action, such as complex I inhibition leading to AMPK activation, have only been observed in the context of supra-pharmacological (>1 mM) metformin concentrations, which do not occur in the clinical setting. Thus, these mechanisms have been challenged in recent years and new mechanisms have been proposed. Based on the observation that metformin alters cellular redox balance, a redox-dependent mechanism of action has been described by several groups. Recent studies have shown that clinically relevant (50-100 μM) concentrations of metformin inhibit hepatic gluconeogenesis in a substrate-selective manner both in vitro and in vivo, supporting a redox-dependent mechanism of metformin action. Here, we review the current literature regarding metformin's cellular and molecular mechanisms of action.
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Affiliation(s)
- Traci E LaMoia
- Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut.,Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Gerald I Shulman
- Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut.,Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
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22
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Rojas-Rodriguez R, Ziegler R, DeSouza T, Majid S, Madore AS, Amir N, Pace VA, Nachreiner D, Alfego D, Mathew J, Leung K, Moore Simas TA, Corvera S. PAPPA-mediated adipose tissue remodeling mitigates insulin resistance and protects against gestational diabetes in mice and humans. Sci Transl Med 2020; 12:eaay4145. [PMID: 33239385 PMCID: PMC8375243 DOI: 10.1126/scitranslmed.aay4145] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 04/25/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022]
Abstract
Pregnancy is a physiological state of continuous adaptation to changing maternal and fetal nutritional needs, including a reduction of maternal insulin sensitivity allowing for appropriately enhanced glucose availability to the fetus. However, excessive insulin resistance in conjunction with insufficient insulin secretion results in gestational diabetes mellitus (GDM), greatly increasing the risk for pregnancy complications and predisposing both mothers and offspring to future metabolic disease. Here, we report a signaling pathway connecting pregnancy-associated plasma protein A (PAPPA) with adipose tissue expansion in pregnancy. Adipose tissue plays a central role in the regulation of insulin sensitivity, and we show that, in both mice and humans, pregnancy caused remodeling of adipose tissue evidenced by altered adipocyte size, vascularization, and in vitro expansion capacity. PAPPA is known to be a metalloprotease secreted by human placenta that modulates insulin-like growth factor (IGF) bioavailability through prolteolysis of IGF binding proteins (IGFBPs) 2, 4, and 5. We demonstrate that recombinant PAPPA can stimulate ex vivo human adipose tissue expansion in an IGFBP-5- and IGF-1-dependent manner. Moreover, mice lacking PAPPA displayed impaired adipose tissue remodeling, pregnancy-induced insulin resistance, and hepatic steatosis, recapitulating multiple aspects of human GDM. In a cohort of 6361 pregnant women, concentrations of circulating PAPPA are inversely correlated with glycemia and odds of developing GDM. These data identify PAPPA and the IGF signaling pathway as necessary for the regulation of maternal adipose tissue physiology and systemic glucose homeostasis, with consequences for long-term metabolic risk and potential for therapeutic use.
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Affiliation(s)
- Raziel Rojas-Rodriguez
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
- Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rachel Ziegler
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Tiffany DeSouza
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sana Majid
- Clinical Translational Research Pathway, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Aylin S Madore
- Departments of Obstetrics and Gynecology, University of Massachusetts Medical School and UMass Memorial Healthcare, Worcester, MA 01605, USA
| | - Nili Amir
- Departments of Obstetrics and Gynecology, University of Massachusetts Medical School and UMass Memorial Healthcare, Worcester, MA 01605, USA
| | - Veronica A Pace
- Clinical Translational Research Pathway, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Daniel Nachreiner
- Clinical Translational Research Pathway, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - David Alfego
- Division of Data Sciences and Technology, IT, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jomol Mathew
- Division of Data Sciences and Technology, IT, University of Massachusetts Medical School, Worcester, MA 01605, USA
- Department of Population and Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Katherine Leung
- Departments of Obstetrics and Gynecology, University of Massachusetts Medical School and UMass Memorial Healthcare, Worcester, MA 01605, USA
| | - Tiffany A Moore Simas
- Departments of Obstetrics and Gynecology, University of Massachusetts Medical School and UMass Memorial Healthcare, Worcester, MA 01605, USA
| | - Silvia Corvera
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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23
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Bergman RN. Origins and History of the Minimal Model of Glucose Regulation. Front Endocrinol (Lausanne) 2020; 11:583016. [PMID: 33658981 PMCID: PMC7917251 DOI: 10.3389/fendo.2020.583016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 12/22/2020] [Indexed: 01/17/2023] Open
Abstract
It has long been hoped that our understanding of the pathogenesis of diabetes would be helped by the use of mathematical modeling. In 1979 Richard Bergman and Claudio Cobelli worked together to find a "minimal model" based upon experimental data from Bergman's laboratory. Model was chosen as the simplest representation based upon physiology known at the time. The model itself is two quasi-linear differential equations; one representing insulin kinetics in plasma, and a second representing the effects of insulin and glucose itself on restoration of the glucose after perturbation by intravenous injection. Model would only be sufficient if it included a delay in insulin action; that is, insulin had to enter a remote compartment, which was interstitial fluid (ISF). Insulin suppressed endogenous glucose output (by liver) slowly. Delay proved to be due to initial suppression of lipolysis; resultant lowering of free fatty acids reduced liver glucose output. Modeling also demanded that normalization of glucose after injection included an effect of glucose itself on glucose disposal and endogenous glucose production - these effects were termed "glucose effectiveness." Insulin sensitivity was calculated from fitting the model to intravenous glucose tolerance test data; the resulting insulin sensitivity index, SI, was validated with the glucose clamp method in human subjects. Model allowed us to examine the relationship between insulin sensitivity and insulin secretion. Relationship was described by a rectangular hyperbola, such that Insulin Secretion x Insulin Sensitivity = Disposition Index (DI). Latter term represents ability of the pancreatic beta-cells to compensate for insulin resistance due to factors such as obesity, pregnancy, or puberty. DI has a genetic basis, and predicts the onset of Type 2 diabetes. An additional factor was clearance of insulin by the liver. Clearance varies significantly among animal or human populations; using the model, clearance was shown to be lower in African Americans than Whites (adults and children), and may be a factor accounting for greater diabetes prevalence in African Americans. The research outlined in the manuscript emphasizes the powerful approach by which hypothesis testing, experimental studies, and mathematical modeling can work together to explain the pathogenesis of metabolic disease.
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24
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Calcium Signaling in ß-cell Physiology and Pathology: A Revisit. Int J Mol Sci 2019; 20:ijms20246110. [PMID: 31817135 PMCID: PMC6940736 DOI: 10.3390/ijms20246110] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 11/28/2019] [Accepted: 12/02/2019] [Indexed: 12/12/2022] Open
Abstract
Pancreatic beta (β) cell dysfunction results in compromised insulin release and, thus, failed regulation of blood glucose levels. This forms the backbone of the development of diabetes mellitus (DM), a disease that affects a significant portion of the global adult population. Physiological calcium (Ca2+) signaling has been found to be vital for the proper insulin-releasing function of β-cells. Calcium dysregulation events can have a dramatic effect on the proper functioning of the pancreatic β-cells. The current review discusses the role of calcium signaling in health and disease in pancreatic β-cells and provides an in-depth look into the potential role of alterations in β-cell Ca2+ homeostasis and signaling in the development of diabetes and highlights recent work that introduced the current theories on the connection between calcium and the onset of diabetes.
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25
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Abstract
Obesity and type 2 diabetes are the most frequent metabolic disorders, but their causes remain largely unclear. Insulin resistance, the common underlying abnormality, results from imbalance between energy intake and expenditure favouring nutrient-storage pathways, which evolved to maximize energy utilization and preserve adequate substrate supply to the brain. Initially, dysfunction of white adipose tissue and circulating metabolites modulate tissue communication and insulin signalling. However, when the energy imbalance is chronic, mechanisms such as inflammatory pathways accelerate these abnormalities. Here we summarize recent studies providing insights into insulin resistance and increased hepatic gluconeogenesis associated with obesity and type 2 diabetes, focusing on data from humans and relevant animal models.
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26
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Bergman RN, Piccinini F, Kabir M, Ader M. Novel aspects of the role of the liver in carbohydrate metabolism. Metabolism 2019; 99:119-125. [PMID: 31158368 PMCID: PMC7216693 DOI: 10.1016/j.metabol.2019.05.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/23/2019] [Accepted: 05/25/2019] [Indexed: 01/21/2023]
Abstract
Malfunction of the liver is a central factor in metabolic disease. Glucose production by liver is complex and controlled via indirect mechanisms; insulin regulates adipose tissue lipolysis, and free fatty acids in turn regulate liver glucose output. This latter concept is confirmed by studies in L-Akt-Foxo1 knockout mice. The adipocyte is a likely locus of hepatic insulin resistance. Also, kidneys play a role in regulating glucose production; denervated kidneys abrogate the effect of fat feeding to cause insulin resistance. Glucose itself is an important regulator of liver metabolism ("glucose effectiveness"); after entering liver, glucose is phosphorylated and can be exported as lactate. Using the dynamic glucose/lactate relationship, we have been able to estimate glucose effectiveness in intact animals and human subjects. Families have been identified with a glucokinase regulatory protein defect; modeling demonstrates elevated glucokinase activity. Insulin clearance by liver is highly variable among normal individuals, and is under environmental control: high fat diet reduces clearance by 30%. Liver insulin clearance is significantly lower in African American (AA) adults and children compared to European American participants, accounting for fasting hyperinsulinemia in AA. We hypothesize that reduced hepatic insulin clearance causes peripheral insulin resistance and increased Type 2 diabetes in AA.
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Affiliation(s)
- Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States of America.
| | - Francesca Piccinini
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States of America
| | - Morvarid Kabir
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States of America
| | - Marilyn Ader
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States of America
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27
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Abstract
PURPOSE OF REVIEW Increased glucose production associated with hepatic insulin resistance contributes to the development of hyperglycemia in T2D. The molecular mechanisms accounting for increased glucose production remain controversial. Our aims were to review recent literature concerning molecular mechanisms regulating glucose production and to discuss these mechanisms in the context of physiological experiments and observations in humans and large animal models. RECENT FINDINGS Genetic intervention studies in rodents demonstrate that insulin can control hepatic glucose production through both direct effects on the liver, and through indirect effects to inhibit adipose tissue lipolysis and limit gluconeogenic substrate delivery. However, recent experiments in canine models indicate that the direct effects of insulin on the liver are dominant over the indirect effects to regulate glucose production. Recent molecular studies have also identified insulin-independent mechanisms by which hepatocytes sense intrahepatic carbohydrate levels to regulate carbohydrate disposal. Dysregulation of hepatic carbohydrate sensing systems may participate in increased glucose production in the development of diabetes.
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Affiliation(s)
- Ashot Sargsyan
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - Mark A Herman
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA.
- Division of Diabetes, Endocrinology, and Metabolism, Duke University, Durham, NC, USA.
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Cappel DA, Deja S, Duarte JAG, Kucejova B, Iñigo M, Fletcher JA, Fu X, Berglund ED, Liu T, Elmquist JK, Hammer S, Mishra P, Browning JD, Burgess SC. Pyruvate-Carboxylase-Mediated Anaplerosis Promotes Antioxidant Capacity by Sustaining TCA Cycle and Redox Metabolism in Liver. Cell Metab 2019; 29:1291-1305.e8. [PMID: 31006591 PMCID: PMC6585968 DOI: 10.1016/j.cmet.2019.03.014] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 01/12/2019] [Accepted: 03/26/2019] [Indexed: 01/09/2023]
Abstract
The hepatic TCA cycle supports oxidative and biosynthetic metabolism. This dual responsibility requires anaplerotic pathways, such as pyruvate carboxylase (PC), to generate TCA cycle intermediates necessary for biosynthesis without disrupting oxidative metabolism. Liver-specific PC knockout (LPCKO) mice were created to test the role of anaplerotic flux in liver metabolism. LPCKO mice have impaired hepatic anaplerosis, diminution of TCA cycle intermediates, suppressed gluconeogenesis, reduced TCA cycle flux, and a compensatory increase in ketogenesis and renal gluconeogenesis. Loss of PC depleted aspartate and compromised urea cycle function, causing elevated urea cycle intermediates and hyperammonemia. Loss of PC prevented diet-induced hyperglycemia and insulin resistance but depleted NADPH and glutathione, which exacerbated oxidative stress and correlated with elevated liver inflammation. Thus, despite catalyzing the synthesis of intermediates also produced by other anaplerotic pathways, PC is specifically necessary for maintaining oxidation, biosynthesis, and pathways distal to the TCA cycle, such as antioxidant defenses.
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Affiliation(s)
- David A Cappel
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Stanisław Deja
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - João A G Duarte
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Blanka Kucejova
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Melissa Iñigo
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Justin A Fletcher
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaorong Fu
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eric D Berglund
- Center for Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Tiemin Liu
- Sate Key Laboratory of Genetic Engineering, School of Life Sciences, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, Shanghai 200438, China
| | - Joel K Elmquist
- Center for Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Suntrea Hammer
- Department of Pathology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Prashant Mishra
- Children's Medical Center Research Institute, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey D Browning
- Department of Clinical Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shawn C Burgess
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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29
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Edgerton DS, Scott M, Farmer B, Williams PE, Madsen P, Kjeldsen T, Brand CL, Fledelius C, Nishimura E, Cherrington AD. Targeting insulin to the liver corrects defects in glucose metabolism caused by peripheral insulin delivery. JCI Insight 2019; 5:126974. [PMID: 30830873 DOI: 10.1172/jci.insight.126974] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Peripheral hyperinsulinemia resulting from subcutaneous insulin injection is associated with metabolic defects which include abnormal glucose metabolism. The first aim of this study was to quantify the impairments in liver and muscle glucose metabolism that occur when insulin is delivered via a peripheral vein compared to when it is given through its endogenous secretory route (the hepatic portal vein) in overnight fasted conscious dogs. The second aim was to determine if peripheral delivery of a hepato-preferential insulin analog could restore the physiologic response to insulin that occurs under meal feeding conditions. This study is the first to show that hepatic glucose uptake correlates with insulin's direct effects on the liver under hyperinsulinemic-hyperglycemic conditions. In addition, glucose uptake was equally divided between the liver and muscle when insulin was infused into the portal vein, but when it was delivered into a peripheral vein the percentage of glucose taken up by muscle was 4-times greater than that going to the liver, with liver glucose uptake being less than half of normal. These defects could not be corrected by adjusting the dose of peripheral insulin. On the other hand, hepatic and non-hepatic glucose metabolism could be fully normalized by a hepato-preferential insulin analog.
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Affiliation(s)
- Dale S Edgerton
- Vanderbilt University School of Medicine, Department of Molecular Physiology and Biophysics, Nashville, Tennessee, USA
| | - Melanie Scott
- Vanderbilt University School of Medicine, Department of Molecular Physiology and Biophysics, Nashville, Tennessee, USA
| | - Ben Farmer
- Vanderbilt University School of Medicine, Department of Molecular Physiology and Biophysics, Nashville, Tennessee, USA
| | - Phillip E Williams
- Vanderbilt University Medical Center, Division of Surgical Research, Nashville, Tennessee, USA
| | - Peter Madsen
- Research and Development, Novo Nordisk A/S, Novo Nordisk Park, Maaleov, Denmark
| | - Thomas Kjeldsen
- Research and Development, Novo Nordisk A/S, Novo Nordisk Park, Maaleov, Denmark
| | - Christian L Brand
- Research and Development, Novo Nordisk A/S, Novo Nordisk Park, Maaleov, Denmark
| | - Christian Fledelius
- Research and Development, Novo Nordisk A/S, Novo Nordisk Park, Maaleov, Denmark
| | - Erica Nishimura
- Research and Development, Novo Nordisk A/S, Novo Nordisk Park, Maaleov, Denmark
| | - Alan D Cherrington
- Vanderbilt University School of Medicine, Department of Molecular Physiology and Biophysics, Nashville, Tennessee, USA
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Perry RJ, Rabin-Court A, Song JD, Cardone RL, Wang Y, Kibbey RG, Shulman GI. Dehydration and insulinopenia are necessary and sufficient for euglycemic ketoacidosis in SGLT2 inhibitor-treated rats. Nat Commun 2019; 10:548. [PMID: 30710078 PMCID: PMC6358621 DOI: 10.1038/s41467-019-08466-w] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 01/07/2019] [Indexed: 12/15/2022] Open
Abstract
Sodium-glucose transport protein 2 (SGLT2) inhibitors are a class of anti-diabetic agents; however, concerns have been raised about their potential to induce euglycemic ketoacidosis and to increase both glucose production and glucagon secretion. The mechanisms behind these alterations are unknown. Here we show that the SGLT2 inhibitor (SGLT2i) dapagliflozin promotes ketoacidosis in both healthy and type 2 diabetic rats in the setting of insulinopenia through increased plasma catecholamine and corticosterone concentrations secondary to volume depletion. These derangements increase white adipose tissue (WAT) lipolysis and hepatic acetyl-CoA content, rates of hepatic glucose production, and hepatic ketogenesis. Treatment with a loop diuretic, furosemide, under insulinopenic conditions replicates the effect of dapagliflozin and causes ketoacidosis. Furthermore, the effects of SGLT2 inhibition to promote ketoacidosis are independent from hyperglucagonemia. Taken together these data in rats identify the combination of insulinopenia and dehydration as a potential target to prevent euglycemic ketoacidosis associated with SGLT2i. The use of sodium-glucose transport protein 2 (SGLT2) inhibitors for the treatment of diabetes has been associated with euglycemic ketoacidosis and increased glucose production and glucagon secretion. Here Perry et al. show that these effects rely on both insulinopenia and dehydration, and thus suggest ways to manage the side effects associated with the use of SGLT2 inhibitors.
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Affiliation(s)
- Rachel J Perry
- Departments of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA.,Departments of Cellular and Molecular Physiology, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA
| | - Aviva Rabin-Court
- Departments of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA
| | - Joongyu D Song
- Departments of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA
| | - Rebecca L Cardone
- Departments of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA
| | - Yongliang Wang
- Departments of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA
| | - Richard G Kibbey
- Departments of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA.,Departments of Cellular and Molecular Physiology, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA
| | - Gerald I Shulman
- Departments of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA. .,Departments of Cellular and Molecular Physiology, Yale University School of Medicine, P.O. Box 208020, TAC S269, New Haven, CT, 06519, USA.
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31
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Homeostasis of Glucose and Lipid in Non-Alcoholic Fatty Liver Disease. Int J Mol Sci 2019; 20:ijms20020298. [PMID: 30642126 PMCID: PMC6359196 DOI: 10.3390/ijms20020298] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/07/2019] [Accepted: 01/09/2019] [Indexed: 02/07/2023] Open
Abstract
Industrialized society-caused dysregular human behaviors and activities such as overworking, excessive dietary intake, and sleep deprivation lead to perturbations in the metabolism and the development of metabolic syndrome. Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease worldwide, affects around 30% and 25% of people in Western and Asian countries, respectively, which leads to numerous medical costs annually. Insulin resistance is the major hallmark of NAFLD and is crucial in the pathogenesis and for the progression from NAFLD to non-alcoholic steatohepatitis (NASH). Excessive dietary intake of saturated fats and carbohydrate-enriched foods contributes to both insulin resistance and NAFLD. Once NAFLD is established, insulin resistance can promote the progression to the more severe state of liver endangerment like NASH. Here, we review current and potential studies for understanding the complexity between insulin-regulated glycolytic and lipogenic homeostasis and the underlying causes of NAFLD. We discuss how disruption of the insulin signal is associated with various metabolic disorders of glucoses and lipids that constitute both the metabolic syndrome and NAFLD.
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32
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Petersen MC, Shulman GI. Mechanisms of Insulin Action and Insulin Resistance. Physiol Rev 2018; 98:2133-2223. [PMID: 30067154 PMCID: PMC6170977 DOI: 10.1152/physrev.00063.2017] [Citation(s) in RCA: 1324] [Impact Index Per Article: 220.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/22/2018] [Accepted: 03/24/2018] [Indexed: 12/15/2022] Open
Abstract
The 1921 discovery of insulin was a Big Bang from which a vast and expanding universe of research into insulin action and resistance has issued. In the intervening century, some discoveries have matured, coalescing into solid and fertile ground for clinical application; others remain incompletely investigated and scientifically controversial. Here, we attempt to synthesize this work to guide further mechanistic investigation and to inform the development of novel therapies for type 2 diabetes (T2D). The rational development of such therapies necessitates detailed knowledge of one of the key pathophysiological processes involved in T2D: insulin resistance. Understanding insulin resistance, in turn, requires knowledge of normal insulin action. In this review, both the physiology of insulin action and the pathophysiology of insulin resistance are described, focusing on three key insulin target tissues: skeletal muscle, liver, and white adipose tissue. We aim to develop an integrated physiological perspective, placing the intricate signaling effectors that carry out the cell-autonomous response to insulin in the context of the tissue-specific functions that generate the coordinated organismal response. First, in section II, the effectors and effects of direct, cell-autonomous insulin action in muscle, liver, and white adipose tissue are reviewed, beginning at the insulin receptor and working downstream. Section III considers the critical and underappreciated role of tissue crosstalk in whole body insulin action, especially the essential interaction between adipose lipolysis and hepatic gluconeogenesis. The pathophysiology of insulin resistance is then described in section IV. Special attention is given to which signaling pathways and functions become insulin resistant in the setting of chronic overnutrition, and an alternative explanation for the phenomenon of ‟selective hepatic insulin resistanceˮ is presented. Sections V, VI, and VII critically examine the evidence for and against several putative mediators of insulin resistance. Section V reviews work linking the bioactive lipids diacylglycerol, ceramide, and acylcarnitine to insulin resistance; section VI considers the impact of nutrient stresses in the endoplasmic reticulum and mitochondria on insulin resistance; and section VII discusses non-cell autonomous factors proposed to induce insulin resistance, including inflammatory mediators, branched-chain amino acids, adipokines, and hepatokines. Finally, in section VIII, we propose an integrated model of insulin resistance that links these mediators to final common pathways of metabolite-driven gluconeogenesis and ectopic lipid accumulation.
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Affiliation(s)
- Max C Petersen
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
| | - Gerald I Shulman
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
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33
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Asare-Bediako I, Paszkiewicz RL, Kim SP, Woolcott OO, Kolka CM, Burch MA, Kabir M, Bergman RN. Variability of Directly Measured First-Pass Hepatic Insulin Extraction and Its Association With Insulin Sensitivity and Plasma Insulin. Diabetes 2018; 67:1495-1503. [PMID: 29752425 PMCID: PMC6054441 DOI: 10.2337/db17-1520] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/03/2018] [Indexed: 01/20/2023]
Abstract
Although the β-cells secrete insulin, the liver, with its first-pass insulin extraction (FPE), regulates the amount of insulin allowed into circulation for action on target tissues. The metabolic clearance rate of insulin, of which FPE is the dominant component, is a major determinant of insulin sensitivity (SI). We studied the intricate relationship among FPE, SI, and fasting insulin. We used a direct method of measuring FPE, the paired portal/peripheral infusion protocol, where insulin is infused stepwise through either the portal vein or a peripheral vein in healthy young dogs (n = 12). FPE is calculated as the difference in clearance rates (slope of infusion rate vs. steady insulin plot) between the paired experiments. Significant correlations were found between FPE and clamp-assessed SI (rs = 0.74), FPE and fasting insulin (rs = -0.64), and SI and fasting insulin (rs = -0.67). We also found a wide variance in FPE (22.4-77.2%; mean ± SD 50.4 ± 19.1) that is reflected in the variability of plasma insulin (48.1 ± 30.9 pmol/L) and SI (9.4 ± 5.8 × 104 dL · kg-1 · min-1 · [pmol/L]-1). FPE could be the nexus of regulation of both plasma insulin and SI.
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Affiliation(s)
| | | | - Stella P Kim
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA
| | - Orison O Woolcott
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA
| | - Cathryn M Kolka
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA
| | - Miguel A Burch
- Cedars-Sinai Medical Center, Department of Surgery, Los Angeles, CA
| | - Morvarid Kabir
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA
| | - Richard N Bergman
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA
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34
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Fang YL, Chen H, Wang CL, Liang L. Pathogenesis of non-alcoholic fatty liver disease in children and adolescence: From “two hit theory” to “multiple hit model”. World J Gastroenterol 2018; 24:2974-2983. [PMID: 30038464 PMCID: PMC6054950 DOI: 10.3748/wjg.v24.i27.2974] [Citation(s) in RCA: 211] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 05/26/2018] [Accepted: 06/27/2018] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) has become the dominant form of chronic liver disease in children and adolescents with the increasing prevalence of obesity worldwide. NAFLD represents a wide spectrum of conditions, ranging from fatty liver - which generally follows a benign, non-progressive clinical course - to non-alcoholic steatohepatitis, a subset of NAFLD that may progress to cirrhosis and end-stage liver disease or liver carcinoma. The underlying pathophysiological mechanism of “pediatric” NAFLD remains unclear, although it is strongly associated with obesity and insulin resistance. In this review we provide a general overview on the current understanding of NAFLD in children and adolescents, which underpins practice, enabling early diagnosis and appropriate therapeutic intervention for this life-threatening liver disease.
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Affiliation(s)
- Yan-Lan Fang
- Department of Pediatrics, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
| | - Hong Chen
- College of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
| | - Chun-Lin Wang
- Department of Pediatrics, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
| | - Li Liang
- Department of Pediatrics, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
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35
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Fuller KN, Valentine RJ, Miranda ER, Kumar P, Prabhakar BS, Haus JM. A single high-fat meal alters human soluble RAGE profiles and PBMC RAGE expression with no effect of prior aerobic exercise. Physiol Rep 2018; 6:e13811. [PMID: 30047241 PMCID: PMC6060105 DOI: 10.14814/phy2.13811] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 07/02/2018] [Indexed: 12/18/2022] Open
Abstract
A high-fat diet can induce inflammation and metabolic diseases such as diabetes and atherosclerosis. The receptor for advanced glycation endproducts (RAGE) plays a critical role in metabolic disease pathophysiology and the soluble form of the receptor (sRAGE) can mitigate these effects. However, little is known about RAGE in the postprandial condition and the effect of exercise in this context. Thus, we aimed to determine the effects of a single high-fat meal (HFM) with and without prior exercise on peripheral blood mononuclear cell (PBMC) RAGE biology. Healthy males (n = 12) consumed a HFM on two occasions, one without prior exercise and one 16-18 hours following acute aerobic exercise. Total soluble RAGE (sRAGE) and endogenous secretory RAGE (esRAGE) were determined via ELISA and cleaved RAGE (cRAGE) was calculated as the difference between the two. Isolated PBMCs were analyzed for RAGE, ADAM10, TLR4, and MyD88 protein expression and ADAM10 activity. The HFM significantly (P < 0.01) attenuated sRAGE, esRAGE, and cRAGE by 9.7%, 6.9%, and 10.5%, respectively. Whereas, the HFM increased PBMC RAGE protein expression by 10.3% (P < 0.01), there was no meal effect on PBMC TLR4, MYD88, or ADAM10 protein expression, nor ADAM10 activity. There was also no exercise effect on any experimental outcomes. These findings suggest that PBMC RAGE and soluble RAGE may be important in the postprandial response to a HFM, and that prior aerobic exercise does not alter these processes in young healthy adult males. The mechanisms by which a HFM induces RAGE expression and reduces circulating soluble RAGE isoforms requires further study.
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Affiliation(s)
- Kelly N.Z. Fuller
- Department of Kinesiology and NutritionUniversity of Illinois at ChicagoChicagoIllinois
| | | | - Edwin R. Miranda
- Department of Kinesiology and NutritionUniversity of Illinois at ChicagoChicagoIllinois
- School of KinesiologyUniversity of MichiganAnn ArborMichigan
| | - Prabhakaran Kumar
- Department of Microbiology and ImmunologyUniversity of Illinois at ChicagoChicagoIllinois
| | - Bellur S. Prabhakar
- Department of Microbiology and ImmunologyUniversity of Illinois at ChicagoChicagoIllinois
| | - Jacob M. Haus
- Department of Kinesiology and NutritionUniversity of Illinois at ChicagoChicagoIllinois
- School of KinesiologyUniversity of MichiganAnn ArborMichigan
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Harvey I, Stephenson EJ, Redd JR, Tran QT, Hochberg I, Qi N, Bridges D. Glucocorticoid-Induced Metabolic Disturbances Are Exacerbated in Obese Male Mice. Endocrinology 2018; 159:2275-2287. [PMID: 29659785 PMCID: PMC5946848 DOI: 10.1210/en.2018-00147] [Citation(s) in RCA: 24] [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: 02/07/2018] [Accepted: 04/05/2018] [Indexed: 12/16/2022]
Abstract
The purpose of this study was to determine the effects of glucocorticoid-induced metabolic dysfunction in the presence of diet-induced obesity. C57BL/6J adult male lean and diet-induced obese mice were given dexamethasone, and levels of hepatic steatosis, insulin resistance, and lipolysis were determined. Obese mice given dexamethasone had significant, synergistic effects on fasting glucose, insulin resistance, and markers of lipolysis, as well as hepatic steatosis. This was associated with synergistic transactivation of the lipolytic enzyme adipose triglyceride lipase. The combination of chronically elevated glucocorticoids and obesity leads to exacerbations in metabolic dysfunction. Our findings suggest lipolysis may be a key player in glucocorticoid-induced insulin resistance and fatty liver in individuals with obesity.
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Affiliation(s)
- Innocence Harvey
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Erin J Stephenson
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - JeAnna R Redd
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Quynh T Tran
- Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Irit Hochberg
- Institute of Endocrinology, Diabetes and Metabolism, Rambam Health Care Campus, Haifa, Israel
| | - Nathan Qi
- Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, Michigan
| | - Dave Bridges
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
- Correspondence: Dave Bridges, PhD, Department of Nutritional Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, Michigan 48109. E-mail:
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Zhang Q, Xu L, Xia J, Wang D, Qian M, Ding S. Treatment of Diabetic Mice with a Combination of Ketogenic Diet and Aerobic Exercise via Modulations of PPARs Gene Programs. PPAR Res 2018; 2018:4827643. [PMID: 29743883 PMCID: PMC5884211 DOI: 10.1155/2018/4827643] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 02/06/2018] [Indexed: 02/07/2023] Open
Abstract
Type 2 diabetes is a prevalent chronic disease arising as a serious public health problem worldwide. Diet intervention is considered to be a critical strategy in glycemic control of diabetic patients. Recently, the low-carbohydrate ketogenic diet is shown to be effective in glycemic control and weight loss. However, hepatic lipid accumulation could be observed in mice treated with ketogenic diet. On the other hand, exercise is a well-known approach for treating nonalcoholic fatty liver disease. We thus hypothesize that the combination of ketogenic diet and exercise could improve insulin sensitivity, while minimizing adverse effect of hepatic steatosis. In order to test this hypothesis, we established diabetic mice model with streptozotocin (STZ) and divided them into control group, ketogenic diet group, and ketogenic diet with aerobic exercise group. We found that after six weeks of intervention, mice treated with ketogenic diet and ketogenic diet combined with exercise both have lower body weights, HbAlc level, HOMA index, and improvements in insulin sensitivity, compared with diabetes group. In addition, mice in ketogenic diet intervention exhibited hepatic steatosis shown by serum and hepatic parameters, as well as histochemistry staining in the liver, which could be largely relieved by exercise. Furthermore, gene analysis revealed that ketogenic diet in combination with exercise reduced PPARγ and lipid synthetic genes, as well as enhancing PPARα and lipid β-oxidation gene program in the liver compared to those in ketogenic diet without exercise. Overall, the present study demonstrated that the combination of ketogenic diet and a moderate-intensity aerobic exercise intervention improved insulin sensitivity in diabetic mice, while avoiding hepatic steatosis, which provided a novel strategy in the combat of diabetes.
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Affiliation(s)
- Qiang Zhang
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai 200241, China
- School of Physical Education & Health Care, East China Normal University, Shanghai 200241, China
| | - Lingyan Xu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Jie Xia
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai 200241, China
- School of Physical Education & Health Care, East China Normal University, Shanghai 200241, China
| | - Dongmei Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Min Qian
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Shuzhe Ding
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai 200241, China
- School of Physical Education & Health Care, East China Normal University, Shanghai 200241, China
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38
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Sam S. Differential effect of subcutaneous abdominal and visceral adipose tissue on cardiometabolic risk. Horm Mol Biol Clin Investig 2018. [PMID: 29522417 DOI: 10.1515/hmbci-2018-0014] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metabolic and cardiovascular diseases are increasing worldwide due to the rise in the obesity epidemic. The metabolic consequences of obesity vary by distribution of adipose tissue. Visceral and ectopic adipose accumulation are associated with adverse cardiometabolic consequences, while gluteal-femoral adipose accumulation are negatively associated with these adverse complications and subcutaneous abdominal adipose accumulation is more neutral in its associations. Gender, race and ethnic differences in adipose tissue distribution have been described and could account for the observed differences in risk for cardiometabolic disease. The mechanisms behind the differential impact of adipose tissue on cardiometabolic risk have started to be unraveled and include differences in adipocyte biology, inflammatory profile, connection to systemic circulation and most importantly the inability of the subcutaneous adipose tissue to expand in response to positive energy balance.
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Affiliation(s)
- Susan Sam
- University of Chicago Pritzker School of Medicine, Department of Medicine, Section of Endocrinology, 5841 S. Maryland Avenue, Chicago, IL 60637, USA, Phone: +773-702 5641, Fax: +773-702 7686
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Samuel VT, Shulman GI. Nonalcoholic Fatty Liver Disease as a Nexus of Metabolic and Hepatic Diseases. Cell Metab 2018; 27:22-41. [PMID: 28867301 PMCID: PMC5762395 DOI: 10.1016/j.cmet.2017.08.002] [Citation(s) in RCA: 446] [Impact Index Per Article: 74.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/01/2017] [Accepted: 08/01/2017] [Indexed: 12/15/2022]
Abstract
NAFLD is closely linked with hepatic insulin resistance. Accumulation of hepatic diacylglycerol activates PKC-ε, impairing insulin receptor activation and insulin-stimulated glycogen synthesis. Peripheral insulin resistance indirectly influences hepatic glucose and lipid metabolism by increasing flux of substrates that promote lipogenesis (glucose and fatty acids) and gluconeogenesis (glycerol and fatty acid-derived acetyl-CoA, an allosteric activator of pyruvate carboxylase). Weight loss with diet or bariatric surgery effectively treats NAFLD, but drugs specifically approved for NAFLD are not available. Some new pharmacological strategies act broadly to alter energy balance or influence pathways that contribute to NAFLD (e.g., agonists for PPAR γ, PPAR α/δ, FXR and analogs for FGF-21, and GLP-1). Others specifically inhibit key enzymes involved in lipid synthesis (e.g., mitochondrial pyruvate carrier, acetyl-CoA carboxylase, stearoyl-CoA desaturase, and monoacyl- and diacyl-glycerol transferases). Finally, a novel class of liver-targeted mitochondrial uncoupling agents increases hepatocellular energy expenditure, reversing the metabolic and hepatic complications of NAFLD.
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Affiliation(s)
- Varman T Samuel
- Department of Medicine, Yale University School of Medicine, New Haven, CT 06510, USA; Veterans Affairs Medical Center, West Haven, CT 06516, USA.
| | - Gerald I Shulman
- Department of Medicine, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA.
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40
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Shestakova MV, Sklyanik IA, Dedov II. [Is it possible to achieve sustained remission or cure of type 2 diabetes mellitus in the 21st century?]. TERAPEVT ARKH 2017; 89:4-11. [PMID: 29171463 DOI: 10.17116/terarkh201789104-11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A practitioner has a wide range of the hypoglycemic drugs for type 2 diabetes mellitus (T2DM) treatment, which can be used within a normal or near-normal range for long-term glycemic control. However, the question remains whether there are ways to achieve not only satisfactory glycemic control, but also T2DM remission (or even complete cure). The review presents an update on the concept of T2DM remission and describes the ways of its possible achievement with non-drug and drug treatments and surgery. The mechanisms of T2DM remission are given.
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Affiliation(s)
- M V Shestakova
- Endocrinology Research Center, Ministry of Health of Russia, Moscow, Russia; M.V. Lomonosov Moscow State University, Moscow, Russia
| | - I A Sklyanik
- Endocrinology Research Center, Ministry of Health of Russia, Moscow, Russia; M.V. Lomonosov Moscow State University, Moscow, Russia
| | - I I Dedov
- Endocrinology Research Center, Ministry of Health of Russia, Moscow, Russia; M.V. Lomonosov Moscow State University, Moscow, Russia
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Jois T, Chen W, Howard V, Harvey R, Youngs K, Thalmann C, Saha P, Chan L, Cowley MA, Sleeman MW. Deletion of hepatic carbohydrate response element binding protein (ChREBP) impairs glucose homeostasis and hepatic insulin sensitivity in mice. Mol Metab 2017; 6:1381-1394. [PMID: 29107286 PMCID: PMC5681238 DOI: 10.1016/j.molmet.2017.07.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 07/11/2017] [Accepted: 07/12/2017] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE Carbohydrate response element binding protein (ChREBP) is a transcription factor that responds to glucose and activates genes involved in the glycolytic and lipogenic pathways. Recent studies have linked adipose ChREBP to insulin sensitivity in mice. However, while ChREBP is most highly expressed in the liver, the effect of hepatic ChREBP on insulin sensitivity remains unknown. To clarify the importance of hepatic ChREBP on glucose homeostasis, we have generated a knockout mouse model that lacks this protein specifically in the liver (Liver-ChREBP KO). METHODS Using Liver-ChREBP KO mice, we investigated whether hepatic ChREBP deletion influences insulin sensitivity, glucose homeostasis and the development of hepatic steatosis utilizing various dietary stressors. Furthermore, we determined gene expression changes in response to fasted and fed states in liver, white, and brown adipose tissues. RESULTS Liver-ChREBP KO mice had impaired insulin sensitivity as indicated by reduced glucose infusion to maintain euglycemia during hyperinsulinemic-euglycemic clamps on both chow (25% lower) and high-fat diet (33% lower) (p < 0.05). This corresponded with attenuated suppression of hepatic glucose production. Although Liver-ChREBP KO mice were protected against carbohydrate-induced hepatic steatosis, they displayed worsened glucose tolerance. Liver-ChREBP KO mice did not show the expected gene expression changes in liver in response to fasted and fed states. Interestingly, hepatic ChREBP deletion also resulted in gene expression changes in white and brown adipose tissues, suggesting inter-tissue communication. This included an almost complete abolition of BAT ChREBPβ induction in the fed state (0.15-fold) (p = 0.015) along with reduced lipogenic genes. In contrast, WAT showed inappropriate increases in lipogenic genes in the fasted state along with increased PEPCK1 in both fasted (3.4-fold) and fed (5.1-fold) states (p < 0.0001). CONCLUSIONS Overall, hepatic ChREBP is protective in regards to hepatic insulin sensitivity and whole body glucose homeostasis. Hepatic ChREBP action can influence other peripheral tissues and is likely essential in coordinating the body's response to different feeding states.
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Affiliation(s)
- Tara Jois
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Weiyi Chen
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Victor Howard
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Rebecca Harvey
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Kristina Youngs
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Claudia Thalmann
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Pradip Saha
- Diabetes and Endocrinology Research Center, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Lawrence Chan
- Diabetes and Endocrinology Research Center, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Michael A Cowley
- Department of Physiology, Monash University, Clayton, Victoria, Australia; Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Mark W Sleeman
- Department of Physiology, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia; Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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42
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Abstract
The liver is crucial for the maintenance of normal glucose homeostasis - it produces glucose during fasting and stores glucose postprandially. However, these hepatic processes are dysregulated in type 1 and type 2 diabetes mellitus, and this imbalance contributes to hyperglycaemia in the fasted and postprandial states. Net hepatic glucose production is the summation of glucose fluxes from gluconeogenesis, glycogenolysis, glycogen synthesis, glycolysis and other pathways. In this Review, we discuss the in vivo regulation of these hepatic glucose fluxes. In particular, we highlight the importance of indirect (extrahepatic) control of hepatic gluconeogenesis and direct (hepatic) control of hepatic glycogen metabolism. We also propose a mechanism for the progression of subclinical hepatic insulin resistance to overt fasting hyperglycaemia in type 2 diabetes mellitus. Insights into the control of hepatic gluconeogenesis by metformin and insulin and into the role of lipid-induced hepatic insulin resistance in modifying gluconeogenic and net hepatic glycogen synthetic flux are also discussed. Finally, we consider the therapeutic potential of strategies that target hepatosteatosis, hyperglucagonaemia and adipose lipolysis.
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Affiliation(s)
- Max C Petersen
- Department of Internal Medicine, Yale School of Medicine
- Department of Cellular &Molecular Physiology, Yale School of Medicine
| | | | - Gerald I Shulman
- Department of Internal Medicine, Yale School of Medicine
- Department of Cellular &Molecular Physiology, Yale School of Medicine
- Howard Hughes Medical Institute, Yale School of Medicine, New Haven, Connecticut 06520, USA
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Subi S, Lee SJ, Shiwani S, Singh NK. Differential characterization of myogenic satellite cells with linolenic and retinoic acid in the presence of thiazolidinediones from prepubertal Korean black goats. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2017; 31:439-448. [PMID: 28920418 PMCID: PMC5838350 DOI: 10.5713/ajas.17.0257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 06/15/2017] [Accepted: 08/31/2017] [Indexed: 12/27/2022]
Abstract
Objective Myogenic satellite cells were isolated from semitendinosus muscle of prepubertal Korean black goat to observe the differential effect of linolenic and retinoic acid in thepresence of thiazolidinediones (TZD) and also to observe the production insulin sensitive preadipocyte. Methods Cells were characterized for their stemness with cluster of differentiation 34 (CD34), CD13, CD106, CD44, Vimentin surface markers using flow cytometry. Cells characterized themselves as possessing significant (p<0.05) levels of CD13, CD34, CD106, Vimentin revealing their stemness potential. Goat myogenic satellite cells also exhibited CD44, indicating that they possessed a % of stemness factors of adipose lineage apart from their inherent stemness of paxillin factors 3/7. Results Cells during proliferation stayed absolutely and firmly within the myogenic fate without any external cues and continued to show a significant (p<0.05) fusion index % to express myogenic differentiation, myosin heavy chain, and smooth muscle actin in 2% horse serum. However, confluent myogenic satellite cells were the ones easily turning into adipogenic lineage. Intriguingly, upregulation in adipose specific genetic markers such as peroxisome proliferation-activated receptor γ, adiponectin, lipoprotein lipase, and CCAAT/enhancer binding protein α were observed and confirmed in all given treatments. However, the amount of adipogenesis was found to be statistically significant (p<0.01) with linolenic acid as compared to retinoic acid in combination with TZD’s. Conclusion Retinoic acid was found to produce smaller preadipocytes which have been assumed to have insulin sensitization and hence retinoic acid could be used as a potential agent to sensitize tissues to insulin in combination with TZD’s to treat diabetic conditions in humans and animals in future.
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Affiliation(s)
- S Subi
- College of Animal life sciences, Kangwon National University, Chuncheon 24341, Korea
| | - S J Lee
- College of Animal life sciences, Kangwon National University, Chuncheon 24341, Korea
| | - S Shiwani
- College of Animal life sciences, Kangwon National University, Chuncheon 24341, Korea
| | - N K Singh
- Department of Veterinary Surgery and Radiology, Faculty of Veterinary and Animal Sciences, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
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44
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Insulin action and resistance in obesity and type 2 diabetes. Nat Med 2017; 23:804-814. [PMID: 28697184 DOI: 10.1038/nm.4350] [Citation(s) in RCA: 754] [Impact Index Per Article: 107.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 05/11/2017] [Indexed: 12/12/2022]
Abstract
Nutritional excess is a major forerunner of type 2 diabetes. It enhances the secretion of insulin, but attenuates insulin's metabolic actions in the liver, skeletal muscle and adipose tissue. However, conflicting evidence indicates a lack of knowledge of the timing of these events during the development of obesity and diabetes, pointing to a key gap in our understanding of metabolic disease. This Perspective reviews alternate viewpoints and recent results on the temporal and mechanistic connections between hyperinsulinemia, obesity and insulin resistance. Although much attention has addressed early steps in the insulin signaling cascade, insulin resistance in obesity seems to be largely elicited downstream of these steps. New findings also connect insulin resistance to extensive metabolic cross-talk between the liver, adipose tissue, pancreas and skeletal muscle. These and other advances over the past 5 years offer exciting opportunities and daunting challenges for the development of new therapeutic strategies for the treatment of type 2 diabetes.
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45
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Insulin Resistance and NAFLD: A Dangerous Liaison beyond the Genetics. CHILDREN-BASEL 2017; 4:children4080074. [PMID: 28805745 PMCID: PMC5575596 DOI: 10.3390/children4080074] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 02/08/2023]
Abstract
Over the last decade, the understanding of the association between insulin resistance (IR) and non-alcoholic fatty liver disease (NAFLD) has dramatically evolved. There is clear understanding that carriers of some common genetic variants, i.e., the patatin-like phospholipase domain-containing 3 (PNPLA3) or the transmembrane 6 superfamily member 2 (TM6SF2) are at risk of developing severe forms of NAFLD even in the presence of reduced or absent IR. In contrast, there are obese patients with “metabolic” (non-genetically driven) NAFLD who present severe IR. Owing to the epidemic obesity and the high prevalence of these genetic variants in the general population, the number of pediatric cases with combination of genetic and metabolic NAFLD is expected to be very high. Gut dysbiosis, excessive dietary intake of saturated fats/fructose-enriched foods and exposure to some chemicals contribute all to both IR and NAFLD, adding further complexity to the understanding of their relationship. Once NAFLD is established, IR can accelerate the progression to the more severe form of liver derangement that is the non-alcoholic steatohepatitis.
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46
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Bergman RN, Iyer MS. Indirect Regulation of Endogenous Glucose Production by Insulin: The Single Gateway Hypothesis Revisited. Diabetes 2017. [PMID: 28637826 DOI: 10.2337/db16-1320] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
On the basis of studies that investigated the intraportal versus systemic insulin infusion and transendothelial transport of insulin, we proposed the "single gateway hypothesis," which supposes an indirect regulation of hepatic glucose production by insulin; the rate-limiting transport of insulin across the adipose tissue capillaries is responsible for the slow suppression of free fatty acids (FFAs), which in turn is responsible for delayed suppression of hepatic endogenous glucose production (EGP) during insulin infusion. Preventing the fall in plasma FFAs during insulin infusion either by administering intralipids or by inhibiting adipose tissue lipolysis led to failure in EGP suppression, thus supporting our hypothesis. More recently, mice lacking hepatic Foxo1 in addition to Akt1 and Akt2 (L-AktFoxo1TKO), all required for insulin signaling, surprisingly showed normal glycemia. Inhibiting the fall of plasma FFAs in these mice prevented the suppression of EGP during a clamp, reaffirming that the site of insulin action to control EGP is extrahepatic. Measuring whole-body turnover rates of glucose and FFAs in L-AktFoxo1TKO mice also confirmed that hepatic EGP was regulated by insulin-mediated control of FFAs. The knockout mouse model in combination with sophisticated molecular techniques confirmed our physiological findings and the single gateway hypothesis.
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Affiliation(s)
- Richard N Bergman
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA
| | - Malini S Iyer
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA
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Titchenell PM, Lazar MA, Birnbaum MJ. Unraveling the Regulation of Hepatic Metabolism by Insulin. Trends Endocrinol Metab 2017; 28:497-505. [PMID: 28416361 PMCID: PMC5477655 DOI: 10.1016/j.tem.2017.03.003] [Citation(s) in RCA: 236] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/15/2017] [Accepted: 03/23/2017] [Indexed: 01/26/2023]
Abstract
During insulin-resistant states such as type 2 diabetes mellitus (T2DM), insulin fails to suppress hepatic glucose production but promotes lipid synthesis leading to hyperglycemia and hypertriglyceridemia. Defining the downstream signaling pathways underlying the control of hepatic metabolism by insulin is necessary for understanding both normal physiology and the pathogenesis of metabolic disease. We summarize recent literature highlighting the importance of both hepatic and extrahepatic mechanisms in insulin regulation of liver glucose and lipid metabolism. We posit that a failure of insulin to inappropriately regulate liver metabolism during T2DM is not exclusively from an inherent defect in canonical liver insulin signaling but is instead due to a combination of hyperinsulinemia, altered substrate supply, and the input of several extrahepatic signals.
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Affiliation(s)
- Paul M Titchenell
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
| | - Mitchell A Lazar
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Morris J Birnbaum
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Present address: Internal Medicine, Pfizer Inc., Cambridge, MA, USA.
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48
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Abstract
Adipose tissue represents a critical component in healthy energy homeostasis. It fulfills important roles in whole-body lipid handling, serves as the body's major energy storage compartment and insulation barrier, and secretes numerous endocrine mediators such as adipokines or lipokines. As a consequence, dysfunction of these processes in adipose tissue compartments is tightly linked to severe metabolic disorders, including obesity, metabolic syndrome, lipodystrophy, and cachexia. While numerous studies have addressed causes and consequences of obesity-related adipose tissue hypertrophy and hyperplasia for health, critical pathways and mechanisms in (involuntary) adipose tissue loss as well as its systemic metabolic consequences are far less understood. In this review, we discuss the current understanding of conditions of adipose tissue wasting and review microenvironmental determinants of adipocyte (dys)function in related pathophysiologies.
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Affiliation(s)
- Alexandros Vegiopoulos
- Junior Group Metabolism and Stem Cell Plasticity, German Cancer Research Center (DKFZ) Heidelberg, Heidelberg, Germany
| | - Maria Rohm
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Stephan Herzig
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Joint Heidelberg-IDC Translational Diabetes Program Inner Medicine I, Neuherberg, Germany
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49
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Caprio S, Perry R, Kursawe R. Adolescent Obesity and Insulin Resistance: Roles of Ectopic Fat Accumulation and Adipose Inflammation. Gastroenterology 2017; 152:1638-1646. [PMID: 28192105 PMCID: PMC9390070 DOI: 10.1053/j.gastro.2016.12.051] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/13/2016] [Accepted: 12/14/2016] [Indexed: 12/17/2022]
Abstract
As a consequence of the global rise in the prevalence of adolescent obesity, an unprecedented phenomenon of type 2 diabetes has emerged in pediatrics. At the heart of the development of type 2 diabetes lies a key metabolic derangement: insulin resistance (IR). Despite the widespread occurrence of IR affecting an unmeasurable number of youths worldwide, its pathogenesis remains elusive. IR in obese youth is a complex phenomenon that defies explanation by a single pathway. In this review we first describe recent data on the prevalence, severity, and racial/ethnic differences in pediatric obesity. We follow by elucidating the initiating events associated with the onset of IR, and describe a distinct "endophenotype" in obese adolescents characterized by a thin superficial layer of abdominal subcutaneous adipose tissue, increased visceral adipose tissue, marked IR, dyslipidemia, and fatty liver. Further, we provide evidence for the cellular and molecular mechanisms associated with this peculiar endophenotype and its relations to IR in the obese adolescent.
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Affiliation(s)
- Sonia Caprio
- Department of Pediatric Endocrinology, Yale University School of Medicine, New Haven, Connecticut.
| | - Rachel Perry
- Department of Internal Medicine, Endocrinology, Yale
University School of Medicine, New Haven, Connecticut
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50
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Edgerton DS, Kraft G, Smith M, Farmer B, Williams PE, Coate KC, Printz RL, O'Brien RM, Cherrington AD. Insulin's direct hepatic effect explains the inhibition of glucose production caused by insulin secretion. JCI Insight 2017; 2:e91863. [PMID: 28352665 DOI: 10.1172/jci.insight.91863] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Insulin can inhibit hepatic glucose production (HGP) by acting directly on the liver as well as indirectly through effects on adipose tissue, pancreas, and brain. While insulin's indirect effects are indisputable, their physiologic role in the suppression of HGP seen in response to increased insulin secretion is not clear. Likewise, the mechanisms by which insulin suppresses lipolysis and pancreatic α cell secretion under physiologic circumstances are also debated. In this study, insulin was infused into the hepatic portal vein to mimic increased insulin secretion, and insulin's indirect liver effects were blocked either individually or collectively. During physiologic hyperinsulinemia, plasma free fatty acid (FFA) and glucagon levels were clamped at basal values and brain insulin action was blocked, but insulin's direct effects on the liver were left intact. Insulin was equally effective at suppressing HGP when its indirect effects were absent as when they were present. In addition, the inhibition of lipolysis, as well as glucagon and insulin secretion, did not require CNS insulin action or decreased plasma FFA. This indicates that the rapid suppression of HGP is attributable to insulin's direct effect on the liver and that its indirect effects are redundant in the context of a physiologic increase in insulin secretion.
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Affiliation(s)
- Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Phillip E Williams
- Division of Surgical Research, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Katie C Coate
- Samford University, Department of Nutrition and Dietetics, Birmingham, Alabama, USA
| | - Richard L Printz
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Richard M O'Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
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