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Brayner B, Keske MA, Roberts-Thomson KM, Parker L, Betik AC, Thomas HJ, Mason S, Way KL, Livingstone KM, Hamilton DL, Kaur G. Short-term high-calorie high-fat feeding induces hyperinsulinemia and blunts skeletal muscle microvascular blood flow in healthy humans. Am J Physiol Endocrinol Metab 2024; 327:E42-E54. [PMID: 38717363 DOI: 10.1152/ajpendo.00070.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/01/2024] [Accepted: 05/02/2024] [Indexed: 06/22/2024]
Abstract
Skeletal muscle microvascular blood flow (MBF) plays an important role in glucose disposal in muscle. Impairments in muscle MBF contribute to insulin resistance and prediabetes. Animal studies show that short-term (3 day) high-fat feeding blunts skeletal muscle MBF before impairing insulin-stimulated glucose disposal. It is not known whether this occurs in humans. We investigated the temporal impact of a 7-day high-calorie high-fat (HCHF) diet intervention (+52% kJ; 41% fat) on fasting and postprandial cardiometabolic outcomes in 14 healthy adults (18-37 yr). Metabolic health and vascular responses to a mixed-meal challenge (MMC) were measured at pre (day 0)-, mid (day 4)- and post (day 8)-intervention. There were no significant differences in body weight, body fat %, fasting blood glucose, and fasting plasma insulin concentrations at pre-, mid- and postintervention. Compared with preintervention there was a significant increase in insulin (but not glucose) total area under the curve in response to the MMC at midintervention (P = 0.041) and at postintervention (P = 0.028). Unlike at pre- and midintervention, at postintervention muscle MBF decreased at 60 min (P = 0.024) and 120 min (P = 0.023) after the MMC. However, macrovascular blood flow was significantly increased from 0 to 60 min (P < 0.001) and 120 min (P < 0.001) after the MMC at pre-, mid- and postintervention. Therefore, short-term HCHF feeding in healthy individuals leads to elevated postprandial insulin but not glucose levels and a blunting of meal-induced skeletal muscle MBF responses but not macrovascular blood flow responses.NEW & NOTEWORTHY This is the first study to investigate skeletal muscle microvascular blood flow (MBF) responses in humans after short-term high-calorie high-fat (HCHF) diet. The main findings were that HCHF diet causes elevated postprandial insulin in healthy individuals within 3 days and blunts meal-induced muscle MBF within 7 days, despite no impairments in postprandial glucose or macrovascular blood flow.
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Affiliation(s)
- Barbara Brayner
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Michelle A Keske
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | | | - Lewan Parker
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Andrew C Betik
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Hannah J Thomas
- Institute for Health and Sport, Victoria University, Melbourne, Victoria, Australia
| | - Shaun Mason
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Kimberley L Way
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Exercise Physiology and Cardiovascular Health Lab, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Katherine M Livingstone
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - D Lee Hamilton
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Gunveen Kaur
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
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White MR, Yates DT. Dousing the flame: reviewing the mechanisms of inflammatory programming during stress-induced intrauterine growth restriction and the potential for ω-3 polyunsaturated fatty acid intervention. Front Physiol 2023; 14:1250134. [PMID: 37727657 PMCID: PMC10505810 DOI: 10.3389/fphys.2023.1250134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/14/2023] [Indexed: 09/21/2023] Open
Abstract
Intrauterine growth restriction (IUGR) arises when maternal stressors coincide with peak placental development, leading to placental insufficiency. When the expanding nutrient demands of the growing fetus subsequently exceed the capacity of the stunted placenta, fetal hypoxemia and hypoglycemia result. Poor fetal nutrient status stimulates greater release of inflammatory cytokines and catecholamines, which in turn lead to thrifty growth and metabolic programming that benefits fetal survival but is maladaptive after birth. Specifically, some IUGR fetal tissues develop enriched expression of inflammatory cytokine receptors and other signaling cascade components, which increases inflammatory sensitivity even when circulating inflammatory cytokines are no longer elevated after birth. Recent evidence indicates that greater inflammatory tone contributes to deficits in skeletal muscle growth and metabolism that are characteristic of IUGR offspring. These deficits underlie the metabolic dysfunction that markedly increases risk for metabolic diseases in IUGR-born individuals. The same programming mechanisms yield reduced metabolic efficiency, poor body composition, and inferior carcass quality in IUGR-born livestock. The ω-3 polyunsaturated fatty acids (PUFA) are diet-derived nutraceuticals with anti-inflammatory effects that have been used to improve conditions of chronic systemic inflammation, including intrauterine stress. In this review, we highlight the role of sustained systemic inflammation in the development of IUGR pathologies. We then discuss the potential for ω-3 PUFA supplementation to improve inflammation-mediated growth and metabolic deficits in IUGR offspring, along with potential barriers that must be considered when developing a supplementation strategy.
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Affiliation(s)
| | - Dustin T. Yates
- Stress Physiology Laboratory, Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, United States
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3
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Is vascular insulin resistance an early step in diet-induced whole-body insulin resistance? Nutr Diabetes 2022; 12:31. [PMID: 35676248 PMCID: PMC9177754 DOI: 10.1038/s41387-022-00209-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/09/2022] [Accepted: 05/25/2022] [Indexed: 11/30/2022] Open
Abstract
There is increasing evidence that skeletal muscle microvascular (capillary) blood flow plays an important role in glucose metabolism by increasing the delivery of glucose and insulin to the myocytes. This process is impaired in insulin-resistant individuals. Studies suggest that in diet-induced insulin-resistant rodents, insulin-mediated skeletal muscle microvascular blood flow is impaired post-short-term high fat feeding, and this occurs before the development of myocyte or whole-body insulin resistance. These data suggest that impaired skeletal muscle microvascular blood flow is an early vascular step before the onset of insulin resistance. However, evidence of this is still lacking in humans. In this review, we summarise what is known about short-term high-calorie and/or high-fat feeding in humans. We also explore selected animal studies to identify potential mechanisms. We discuss future directions aimed at better understanding the ‘early’ vascular mechanisms that lead to insulin resistance as this will provide the opportunity for much earlier screening and timing of intervention to assist in preventing type 2 diabetes.
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Liu J, Aylor KW, Chai W, Barrett EJ, Liu Z. Metformin prevents endothelial oxidative stress and microvascular insulin resistance during obesity development in male rats. Am J Physiol Endocrinol Metab 2022; 322:E293-E306. [PMID: 35128961 PMCID: PMC8897003 DOI: 10.1152/ajpendo.00240.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 11/22/2022]
Abstract
Insulin increases muscle microvascular perfusion, which contributes to its metabolic action in muscle, but this action is impaired in obesity. Metformin improves endothelial function beyond its glucose lowering effects. We aim to examine whether metformin could prevent microvascular insulin resistance and endothelial dysfunction during the development of obesity. Adult male rats were fed a high-fat diet (HFD) with or without simultaneous metformin administration for either 2 or 4 wk. Insulin's metabolic and microvascular actions were determined using a combined euglycemic-hyperinsulinemic clamp and contrast-enhanced ultrasound approach. Compared with chow-fed controls, HFD feeding increased body adiposity without excess body weight gain, and this was associated with a marked decrease in insulin-mediated whole body glucose disposal and abolishment of insulin-induced muscle microvascular recruitment. Simultaneous administration of metformin fully rescued insulin-induced muscle microvascular recruitment as early as 2 wk and normalized insulin-mediated whole body glucose disposal at week 4. The divergent responses between insulin's microvascular and metabolic actions seen at week 2 were accompanied with reduced endothelial oxidative stress and vascular inflammation, and improved endothelial function and vascular insulin signaling in metformin-treated rats. In conclusions, metformin could prevent the development of microvascular insulin resistance and endothelial dysfunction by alleviating endothelial oxidative stress and vascular inflammation during obesity development.NEW & NOTEWORTHY Muscle microvascular insulin action contributes to insulin-mediated glucose use. Microvascular insulin resistance is an early event in diet-induced obesity and is associated with vascular inflammation. Metformin effectively reduces endothelial oxidative stress, improves endothelial function, and prevents microvascular insulin resistance during obesity development. These may contribute to metformin's salutary diabetes prevention and cardiovascular protective actions.
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Affiliation(s)
- Jia Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
| | - Kevin W Aylor
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
| | - Weidong Chai
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
| | - Eugene J Barrett
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
| | - Zhenqi Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
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Hicks ZM, Yates DT. Going Up Inflame: Reviewing the Underexplored Role of Inflammatory Programming in Stress-Induced Intrauterine Growth Restricted Livestock. FRONTIERS IN ANIMAL SCIENCE 2021; 2. [PMID: 34825243 PMCID: PMC8612632 DOI: 10.3389/fanim.2021.761421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The impact of intrauterine growth restriction (IUGR) on health in humans is well-recognized. It is the second leading cause of perinatal mortality worldwide, and it is associated with deficits in metabolism and muscle growth that increase lifelong risk for hypertension, obesity, hyperlipidemia, and type 2 diabetes. Comparatively, the barrier that IUGR imposes on livestock production is less recognized by the industry. Meat animals born with low birthweight due to IUGR are beset with greater early death loss, inefficient growth, and reduced carcass merit. These animals exhibit poor feed-to-gain ratios, less lean mass, and greater fat deposition, which increase production costs and decrease value. Ultimately, this reduces the amount of meat produced by each animal and threatens the economic sustainability of livestock industries. Intrauterine growth restriction is most commonly the result of fetal programming responses to placental insufficiency, but the exact mechanisms by which this occurs are not well-understood. In uncompromised pregnancies, inflammatory cytokines are produced at modest rates by placental and fetal tissues and play an important role in fetal development. However, unfavorable intrauterine conditions can cause cytokine activity to be excessive during critical windows of fetal development. Our recent evidence indicates that this impacts developmental programming of muscle growth and metabolism and contributes to the IUGR phenotype. In this review, we outline the role of inflammatory cytokine activity in the development of normal and IUGR phenotypes. We also highlight the contributions of sheep and other animal models in identifying mechanisms for IUGR pathologies.
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Affiliation(s)
- Zena M Hicks
- Stress Physiology Laboratory, Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Dustin T Yates
- Stress Physiology Laboratory, Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, United States
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Ramos-Arellano LE, Matia-Garcia I, Marino-Ortega LA, Castro-Alarcón N, Muñoz-Valle JF, Salgado-Goytia L, Salgado-Bernabé AB, Parra-Rojas I. Obesity, dyslipidemia, and high blood pressure are associated with cardiovascular risk, determined using high-sensitivity C-reactive protein concentration, in young adults. J Int Med Res 2020; 48:300060520980596. [PMID: 33342336 PMCID: PMC7756045 DOI: 10.1177/0300060520980596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective Few studies have investigated the relationships between high-sensitivity C-reactive protein (hs-CRP) concentration and conventional cardiometabolic markers in young adults. The aim of this study was to characterize the cardiometabolic profile of young adults who are at high cardiovascular risk, according to hs-CRP concentration. Methods A cross-sectional study was conducted in 300 young adults (18 to 30 years old) from southern Mexico (n = 150 normal-weight and n = 150 obese). Their circulating lipid and glucose concentrations were measured using colorimetric enzymatic assays, and their hs-CRP, ApoA, and ApoB concentrations were measured using turbidimetric assays. Results The most prevalent abnormalities in the participants with high cardiovascular risk, determined using an hs-CRP >28.57 nmol/L, were high waist circumference (85.7%), obesity (83.9%), high low-density lipoprotein-cholesterol (64.3%), low high-density lipoprotein-cholesterol (50%), Apo B in the highest tertile (39.3%), hypertriglyceridemia (35.7%), and high blood pressure (30.4%). In addition, there were strong associations between hs-CRP >28.57 nmol/L and obesity (odds ratio [OR] = 13.9), high waist circumference (OR = 8.0), hypertriglyceridemia (OR = 4.0), high blood pressure (OR = 3.4), hypercholesterolemia (OR = 2.8), and Apo B in the highest tertile (OR = 2.4). Conclusion The principal cardiometabolic alterations associated with high cardiovascular risk, determined using hs-CRP, are obesity, dyslipidemia, and high blood pressure in young adults.
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Affiliation(s)
- Luz Elena Ramos-Arellano
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México
| | - Ines Matia-Garcia
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México
| | - Linda Anahi Marino-Ortega
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México
| | - Natividad Castro-Alarcón
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México
| | - José Francisco Muñoz-Valle
- Instituto de Investigación en Ciencias Biomédicas, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, México
| | - Lorenzo Salgado-Goytia
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México
| | | | - Isela Parra-Rojas
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México
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7
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Poole DC, Pittman RN, Musch TI, Østergaard L. August Krogh's theory of muscle microvascular control and oxygen delivery: a paradigm shift based on new data. J Physiol 2020; 598:4473-4507. [PMID: 32918749 DOI: 10.1113/jp279223] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022] Open
Abstract
August Krogh twice won the prestigious international Steegen Prize, for nitrogen metabolism (1906) and overturning the concept of active transport of gases across the pulmonary epithelium (1910). Despite this, at the beginning of 1920, the consummate experimentalist was relatively unknown worldwide and even among his own University of Copenhagen faculty. But, in early 1919, he had submitted three papers to Dr Langley, then editor of The Journal of Physiology in England. These papers coalesced anatomical observations of skeletal muscle capillary numbers with O2 diffusion theory to propose a novel active role for capillaries that explained the prodigious increase in blood-muscle O2 flux from rest to exercise. Despite his own appraisal of the first two papers as "rather dull" to his friend, the eminent Cambridge respiratory physiologist, Joseph Barcroft, Krogh believed that the third one, dealing with O2 supply and capillary regulation, was"interesting". These papers, which won Krogh an unopposed Nobel Prize for Physiology or Medicine in 1920, form the foundation for this review. They single-handedly transformed the role of capillaries from passive conduit and exchange vessels, functioning at the mercy of their upstream arterioles, into independent contractile units that were predominantly closed at rest and opened actively during muscle contractions in a process he termed 'capillary recruitment'. Herein we examine Krogh's findings and some of the experimental difficulties he faced. In particular, the boundary conditions selected for his model (e.g. heavily anaesthetized animals, negligible intramyocyte O2 partial pressure, binary open-closed capillary function) have not withstood the test of time. Subsequently, we update the reader with intervening discoveries that underpin our current understanding of muscle microcirculatory control and place a retrospectroscope on Krogh's discoveries. The perspective is presented that the imprimatur of the Nobel Prize, in this instance, may have led scientists to discount compelling evidence. Much as he and Marie Krogh demonstrated that active transport of gases across the blood-gas barrier was unnecessary in the lung, capillaries in skeletal muscle do not open and close spontaneously or actively, nor is this necessary to account for the increase in blood-muscle O2 flux during exercise. Thus, a contemporary model of capillary function features most muscle capillaries supporting blood flow at rest, and, rather than capillaries actively vasodilating from rest to exercise, increased blood-myocyte O2 flux occurs predominantly via elevating red blood cell and plasma flux in already flowing capillaries. Krogh is lauded for his brilliance as an experimentalist and for raising scientific questions that led to fertile avenues of investigation, including the study of microvascular function.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University Manhattan, Manhattan, KS, 66506, USA
| | - Roland N Pittman
- Department of Physiology and Biophysics, Virginia Commonwealth University Richmond, Richmond, VA, 23298-0551, USA
| | - Timothy I Musch
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University Manhattan, Manhattan, KS, 66506, USA
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
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Love KM, Liu J, Regensteiner JG, Reusch JE, Liu Z. GLP-1 and insulin regulation of skeletal and cardiac muscle microvascular perfusion in type 2 diabetes. J Diabetes 2020; 12:488-498. [PMID: 32274893 PMCID: PMC8393916 DOI: 10.1111/1753-0407.13045] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/24/2020] [Accepted: 03/31/2020] [Indexed: 12/25/2022] Open
Abstract
Muscle microvasculature critically regulates skeletal and cardiac muscle health and function. It provides endothelial surface area for substrate exchange between the plasma compartment and the muscle interstitium. Insulin fine-tunes muscle microvascular perfusion to regulate its own action in muscle and oxygen and nutrient supplies to muscle. Specifically, insulin increases muscle microvascular perfusion, which results in increased delivery of insulin to the capillaries that bathe the muscle cells and then facilitate its own transendothelial transport to reach the muscle interstitium. In type 2 diabetes, muscle microvascular responses to insulin are blunted and there is capillary rarefaction. Both loss of capillary density and decreased insulin-mediated capillary recruitment contribute to a decreased endothelial surface area available for substrate exchange. Vasculature expresses abundant glucagon-like peptide 1 (GLP-1) receptors. GLP-1, in addition to its well-characterized glycemic actions, improves endothelial function, increases muscle microvascular perfusion, and stimulates angiogenesis. Importantly, these actions are preserved in the insulin resistant states. Thus, treatment of insulin resistant patients with GLP-1 receptor agonists may improve skeletal and cardiac muscle microvascular perfusion and increase muscle capillarization, leading to improved delivery of oxygen, nutrients, and hormones such as insulin to the myocytes. These actions of GLP-1 impact skeletal and cardiac muscle function and systems biology such as functional exercise capacity. Preclinical studies and clinical trials involving the use of GLP-1 receptor agonists have shown salutary cardiovascular effects and improved cardiovascular outcomes in type 2 diabetes mellitus. Future studies should further examine the different roles of GLP-1 in cardiac as well as skeletal muscle function.
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Affiliation(s)
- Kaitlin M. Love
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
| | - Jia Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
| | - Judith G. Regensteiner
- Center for Women’s Health Research, University of Colorado School of Medicine, Aurora, Colorado
- Department of Medicine, University of Colorado, Aurora, Colorado
| | - Jane E.B. Reusch
- Center for Women’s Health Research, University of Colorado School of Medicine, Aurora, Colorado
- Department of Medicine, University of Colorado, Aurora, Colorado
- Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, Colorado
| | - Zhenqi Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia
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Roberts-Thomson KM, Betik AC, Premilovac D, Rattigan S, Richards SM, Ross RM, Russell RD, Kaur G, Parker L, Keske MA. Postprandial microvascular blood flow in skeletal muscle: Similarities and disparities to the hyperinsulinaemic-euglycaemic clamp. Clin Exp Pharmacol Physiol 2019; 47:725-737. [PMID: 31868941 DOI: 10.1111/1440-1681.13237] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 12/12/2019] [Accepted: 12/18/2019] [Indexed: 12/22/2022]
Abstract
Skeletal muscle contributes to ~40% of total body mass and has numerous important mechanical and metabolic roles in the body. Skeletal muscle is a major site for glucose disposal following a meal. Consequently, skeletal muscle plays an important role in postprandial blood glucose homeostasis. Over the past number of decades, research has demonstrated that insulin has an important role in vasodilating the vasculature in skeletal muscle in response to an insulin infusion (hyperinsulinaemic-euglycaemic clamp) or following the ingestion of a meal. This vascular action of insulin is pivotal for glucose disposal in skeletal muscle, as insulin-stimulated vasodilation increases the delivery of both glucose and insulin to the myocyte. Notably, in insulin-resistant states such as obesity and type 2 diabetes, this vascular response of insulin in skeletal muscle is significantly impaired. Whereas the majority of work in this field has focussed on the action of insulin alone on skeletal muscle microvascular blood flow and myocyte glucose metabolism, there is less understanding of how the consumption of a meal may affect skeletal muscle blood flow. This is in part due to complex variations in glucose and insulin dynamics that occurs postprandially-with changes in humoral concentrations of glucose, insulin, amino acids, gut and pancreatic peptides-compared to the hyperinsulinaemic-euglycaemic clamp. This review will address the emerging body of evidence to suggest that postprandial blood flow responses in skeletal muscle may be a function of the nutritional composition of a meal.
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Affiliation(s)
- Katherine M Roberts-Thomson
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Andrew C Betik
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Dino Premilovac
- School of Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Stephen Rattigan
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | | | - Renee M Ross
- School of Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Ryan D Russell
- Department of Health and Human Performance, College of Health Professions, University of Texas Rio Grande Valley, Brownsville, TX, USA
| | - Gunveen Kaur
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Lewan Parker
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Michelle A Keske
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia.,Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
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10
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Park HS, Lim JS, Lim SK. Determinants of Bone Mass and Insulin Resistance in Korean Postmenopausal Women: Muscle Area, Strength, or Composition? Yonsei Med J 2019; 60:742-750. [PMID: 31347329 PMCID: PMC6660447 DOI: 10.3349/ymj.2019.60.8.742] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 06/14/2019] [Accepted: 06/18/2019] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Muscle mass, strength, and composition determine muscle quantity and quality. However, data on muscle properties in relation to bone mass or insulin resistance are limited in Asian populations. This study aimed to investigate the relative importance of muscle measurements in regards to their relationship with lower bone mass and insulin resistance. MATERIALS AND METHODS In this study, 192 postmenopausal women (age, 72.39±6.07 years) were enrolled. We measured muscle cross-sectional area (CSA) and attenuation at the gluteus maximus and quadriceps muscles through quantitative computed tomography. Muscle strength and physical performance were evaluated with the hand grip test and Short Physical Performance Battery (SPPB). Pearson correlation analysis and linear regression were performed to evaluate the relationship between muscle properties and homeostatic model assessment-insulin resistance (HOMA-IR) or bone mineral density (BMD). RESULTS Muscle CSA, hand grip strength, and SPPB score held positive correlations with spine and hip BMDs, but not with insulin resistance. In contrast, muscle attenuation of the gluteus maximus or quadriceps was inversely related to HOMA-IR (r=-0.194, p=0.018 and r=-0.292, p<0.001, respectively), but not BMD. Compared with the control group, muscle CSA was significantly decreased in patients with osteoporosis; however, decreased muscle attenuation, indicating high fat infiltration, was found only in patients with diabetes. CONCLUSION Muscle mass, strength, and physical performance were associated with low bone mass, and accumulation of intramuscular fat, a histological hallmark of persistently damaged muscles, may play a major role in the development of insulin resistance in Korean postmenopausal women.
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Affiliation(s)
- Hye Sun Park
- Department of Endocrinology, H Plus Yangji Hospital, Seoul, Korea
| | - Jung Soo Lim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Institute of Evidence-based Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Sung Kil Lim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
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11
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Boam GC, Weber WJ, Benjamin A, Kahl S, Allen Bridges G, Elsasser TH, Kerr D, Crooker BA. Effect of bovine genotype on innate immune response of heifers to repeated lipopolysaccharide (LPS) administration. Vet Immunol Immunopathol 2019; 215:109914. [PMID: 31420065 DOI: 10.1016/j.vetimm.2019.109914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 06/27/2019] [Accepted: 07/30/2019] [Indexed: 01/26/2023]
Abstract
This pilot study provides a preliminary assessment of the impact of genotype on acute innate immune pro-inflammatory, metabolic and endocrine responses to repeated lipopolysaccharide (LPS) administered to growing heifers. Heifers (n = 4/genotype) were from unselected (stable milk yield since 1964, UH) or contemporary (CH) Holstein cows that differed in milk yield (6200 vs 11,100 kg milk/305 d) or from contemporary Black Angus (CA) cows bred to contemporary Red Angus bulls. Heifers were challenged with iv administration of 0.5 μg LPS/kg body weight on day 1 (Challenge 1) and d 5 (Challenge 2) of study to assess endotoxin tolerance. Plasma was collected at -1, -0.5, 0, 1, 2, 3, 4, 6, 8, and 24 h relative to each LPS administration. Rectal body temperature (BT) was measured before each blood sampling and at 5 and 7 h. Data were analyzed by repeated measures with sampling time as the repeated effect. Each genotype had at least one pro-inflammatory response that indicated it might have a more robust response than the other genotypes. The CH heifers had a greater TNF-α response, UH heifers had greater IL-6 and XO responses and CA heifers had greater BT and SAA response to LPS than the other genotypes. There was a genotype by time by interaction as cortisol peaked earlier in CH and UH than in CA heifers. Glucose response was less in CA and insulin response was greater in CH heifers. Endotoxin tolerance to LPS was evident as pro-inflammatory, cortisol, glucose and insulin responses were less during Challenge 2 than during Challenge 1. Differences among genotypes during Challenge 1 were eliminated during Challenge 2 except for the greater SAA response in CA heifers and indicate the potential for differential impacts of genotype on the development of endotoxin tolerance. Specific reasons for these effects of genotype are not clear from these data but the results support the hypothesis for differential innate immune signaling among these bovine genotypes.
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Affiliation(s)
| | - Wanda J Weber
- Department of Animal Science, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Aimee Benjamin
- Department of Animal and Veterinary Sciences, University of Vermont, Burlington, VT, 05405, USA
| | - Stanislaw Kahl
- Animal Biosciences and Biotechnology Laboratory, U. S. Department of Agriculture, Agricultural Research Service, Beltsville, MD, 20705, USA
| | - G Allen Bridges
- Department of Animal Science, University of Minnesota, Grand Rapids, MN, 55744, USA
| | - Theodore H Elsasser
- Animal Biosciences and Biotechnology Laboratory, U. S. Department of Agriculture, Agricultural Research Service, Beltsville, MD, 20705, USA
| | - David Kerr
- Department of Animal and Veterinary Sciences, University of Vermont, Burlington, VT, 05405, USA
| | - Brian A Crooker
- Department of Animal Science, University of Minnesota, Saint Paul, MN, 55108, USA.
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12
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Reitzner SM, Hengevoss J, Isenmann E, Diel P. Modulation of exercise training related adaptation of body composition and regulatory pathways by anabolic steroids. J Steroid Biochem Mol Biol 2019; 190:44-53. [PMID: 30926427 DOI: 10.1016/j.jsbmb.2019.03.023] [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: 02/28/2019] [Revised: 03/25/2019] [Accepted: 03/25/2019] [Indexed: 10/27/2022]
Abstract
Anabolic steroids have a long history of abuse in amateur and professional athletics. However, their interaction with training and the resulting effects on body composition and tissue adaptation, relying on a concert of factors and pathways, remain under investigation. This study aims at investigating the changes of body composition and the expression of selected genes and pathways essential for this adaptation process. Therefore, male wistar rats were treated with the anabolic steroid metandienone in two groups (n = 16; metandienone, metandienone + exercise) alongside with control groups (n = 16; control, exercise). Following a 6-week steep-angle treadmill training protocol, weight of organs, visceral fat and muscles was determined. M. gastrocnemius was histologically assessed by ATPase staining, mRNA and protein levels of factors of regeneration, hypertrophy and myogenesis and selected master regulators and markers were determined. Results show additive effects of anabolic steroids and exercise on body, tibia and reproductive organs weight. Mm. gastrocnemius and soleus weight was increased by training but not anabolic steroids. Muscle fiber diameter and composition remained unchanged. Visceral fat mass and fat cell size was affected by training and anabolic steroids but no additive effects could be observed. Exercise and anabolic steroids result in a complex regulation of the expression of genes in M. Gastrocnemius involved in skeletal muscle metabolism, hypertrophy, inflammation and regeneration. In summary, our data suggests distinct molecular mechanisms involved in the adaptation of the skeletal muscle to anabolic androgenic steroids and exercise. Metandienone treatment neither results in skeletal muscle hypertrophy nor liver-toxic effects but in an induction of skeletal muscle regeneration and an activation of endocrine negative feedback. Moreover our study demonstrates that visceral fat and bone responds with higher sensitivity to ASS and exercise than the skeletal muscle. This apparent plasticity of adipose and bone tissue rather than skeletal muscle could indicate a potentially superior future role of fat rather than muscle related parameters to detect and AAS abuse in a biologic passport strategy in professional athletes.
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Affiliation(s)
| | - Jonas Hengevoss
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Germany
| | - Eduard Isenmann
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Germany
| | - Patrick Diel
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Germany
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Poole DC. Edward F. Adolph Distinguished Lecture. Contemporary model of muscle microcirculation: gateway to function and dysfunction. J Appl Physiol (1985) 2019; 127:1012-1033. [PMID: 31095460 DOI: 10.1152/japplphysiol.00013.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This review strikes at the very heart of how the microcirculation functions to facilitate blood-tissue oxygen, substrate, and metabolite fluxes in skeletal muscle. Contemporary evidence, marshalled from animals and humans using the latest techniques, challenges iconic perspectives that have changed little over the past century. Those perspectives include the following: the presence of contractile or collapsible capillaries in muscle, unitary control by precapillary sphincters, capillary recruitment at the onset of contractions, and the notion of capillary-to-mitochondrial diffusion distances as limiting O2 delivery. Today a wealth of physiological, morphological, and intravital microscopy evidence presents a completely different picture of microcirculatory control. Specifically, capillary red blood cell (RBC) and plasma flux is controlled primarily at the arteriolar level with most capillaries, in healthy muscle, supporting at least some flow at rest. In healthy skeletal muscle, this permits substrate access (whether carried in RBCs or plasma) to a prodigious total capillary surface area. Pathologies such as heart failure or diabetes decrease access to that exchange surface by reducing the proportion of flowing capillaries at rest and during exercise. Capillary morphology and function vary disparately among tissues. The contemporary model of capillary function explains how, following the onset of exercise, muscle O2 uptake kinetics can be extremely fast in health but slowed in heart failure and diabetes impairing contractile function and exercise tolerance. It is argued that adoption of this model is fundamental for understanding microvascular function and dysfunction and, as such, to the design and evaluation of effective therapeutic strategies to improve exercise tolerance and decrease morbidity and mortality in disease.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology, Anatomy and Physiology, Kansas State University, Manhattan, Kansas
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14
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Muscle Insulin Resistance and the Inflamed Microvasculature: Fire from Within. Int J Mol Sci 2019; 20:ijms20030562. [PMID: 30699907 PMCID: PMC6387226 DOI: 10.3390/ijms20030562] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/21/2019] [Accepted: 01/22/2019] [Indexed: 12/18/2022] Open
Abstract
Insulin is a vascular hormone and regulates vascular tone and reactivity. Muscle is a major insulin target that is responsible for the majority of insulin-stimulated glucose use. Evidence confirms that muscle microvasculature is an important insulin action site and critically regulates insulin delivery to muscle and action on myocytes, thereby affecting insulin-mediated glucose disposal. Insulin via activation of its signaling cascade in the endothelial cells increases muscle microvascular perfusion, which leads to an expansion of the endothelial exchange surface area. Insulin’s microvascular actions closely couple with its metabolic actions in muscle and blockade of insulin-mediated microvascular perfusion reduces insulin-stimulated muscle glucose disposal. Type 2 diabetes is associated with chronic low-grade inflammation, which engenders both metabolic and microvascular insulin resistance through endocrine, autocrine and paracrine actions of multiple pro-inflammatory factors. Here, we review the crucial role of muscle microvasculature in the regulation of insulin action in muscle and how inflammation in the muscle microvasculature affects insulin’s microvascular actions as well as metabolic actions. We propose that microvascular insulin resistance induced by inflammation is an early event in the development of metabolic insulin resistance and eventually type 2 diabetes and its related cardiovascular complications, and thus is a potential therapeutic target for the prevention or treatment of obesity and diabetes.
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Hu D, Russell RD, Remash D, Greenaway T, Rattigan S, Squibb KA, Jones G, Ross RM, Roberts CK, Premilovac D, Richards SM, Keske MA. Are the metabolic benefits of resistance training in type 2 diabetes linked to improvements in adipose tissue microvascular blood flow? Am J Physiol Endocrinol Metab 2018; 315:E1242-E1250. [PMID: 30351988 DOI: 10.1152/ajpendo.00234.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The microcirculation in adipose tissue is markedly impaired in type 2 diabetes (T2D). Resistance training (RT) often increases muscle mass and promotes a favorable metabolic profile in people with T2D, even in the absence of fat loss. Whether the metabolic benefits of RT in T2D are linked to improvements in adipose tissue microvascular blood flow is unknown. Eighteen sedentary people with T2D (7 women/11 men, 52 ± 7 yr) completed 6 wk of RT. Before and after RT, overnight-fasted participants had blood sampled for clinical chemistries (glucose, insulin, lipids, HbA1c, and proinflammatory markers) and underwent an oral glucose challenge (OGC; 50 g glucose × 2 h) and a DEXA scan to assess body composition. Adipose tissue microvascular blood volume and flow were assessed at rest and 1 h post-OGC using contrast-enhanced ultrasound. RT significantly reduced fasting blood glucose ( P = 0.006), HbA1c ( P = 0.007), 2-h glucose area under the time curve post-OGC ( P = 0.014), and homeostatic model assessment of insulin resistance ( P = 0.005). This was accompanied by a small reduction in total body fat ( P = 0.002), trunk fat ( P = 0.023), and fasting triglyceride levels ( P = 0.029). Lean mass ( P = 0.003), circulating TNF-α ( P = 0.006), and soluble VCAM-1 ( P < 0.001) increased post-RT. There were no significant changes in adipose tissue microvascular blood volume or flow following RT; however those who did have a higher baseline microvascular blood flow post-RT also had lower fasting triglyceride levels ( r = -0.476, P = 0.045). The anthropometric, glycemic, and insulin-sensitizing benefits of 6 wk of RT in people with T2D are not associated with an improvement in adipose tissue microvascular responses; however, there may be an adipose tissue microvascular-linked benefit to fasting triglyceride levels.
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Affiliation(s)
- Donghua Hu
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
- Department of Pharmacology, Anhui Medical University , Hefei , China
| | - Ryan D Russell
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
- Department of Health and Human Performance, College of Health Services, University of Texas Rio Grande Valley , Brownsville, Texas
| | - Devika Remash
- School of Medicine, University of Tasmania , Hobart, Tasmania , Australia
| | - Timothy Greenaway
- School of Medicine, University of Tasmania , Hobart, Tasmania , Australia
- Royal Hobart Hospital , Hobart, Tasmania , Australia
| | - Stephen Rattigan
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
| | - Kathryn A Squibb
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
| | - Graeme Jones
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
| | - Renee M Ross
- School of Medicine, University of Tasmania , Hobart, Tasmania , Australia
| | - Christian K Roberts
- Geriatric Research, Education and Clinical Center, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
| | - Dino Premilovac
- School of Medicine, University of Tasmania , Hobart, Tasmania , Australia
| | - Stephen M Richards
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
- School of Medicine, University of Tasmania , Hobart, Tasmania , Australia
| | - Michelle A Keske
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University , Geelong , Australia
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Emanuel AL, de Clercq NC, Koopen AM, van Poelgeest E, Serlie MJM, van Raalte DH, Kramer MHH, Nieuwdorp M, Eringa EC, Serné EH. Iloprost infusion prevents the insulin-induced reduction in skeletal muscle microvascular blood volume but does not enhance peripheral glucose uptake in type 2 diabetic patients. Diabetes Obes Metab 2018; 20:2523-2531. [PMID: 29885045 DOI: 10.1111/dom.13410] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/22/2018] [Accepted: 06/05/2018] [Indexed: 01/26/2023]
Abstract
AIMS In type 2 diabetes impaired insulin-induced muscle perfusion is thought to contribute to reduced whole-body glucose uptake. In this study, we examined the effects of iloprost, a stable prostacyclin analogue, on insulin-induced muscle capillary recruitment and whole-body glucose uptake. MATERIALS AND METHODS In a randomized cross-over design, 12 type 2 diabetes patients (age, 55 [46-69] years; BMI, 33.1 [31.0-39] kg/m2 ) underwent two hyperinsulinaemic-euglycaemic clamps, one with and one without simultaneous low-dose iloprost infusion. Contrast-enhanced ultrasonography of the vastus lateralis muscle was performed before and during the clamp. Muscle capillary recruitment was calculated as percentage change in microvascular blood volume (MBV) before and during the clamp. RESULTS Insulin infusion reduced skeletal muscle MBV by ~50% compared to the fasting state (fasting, 1.77·10-4 [1.54·10-5 -2.44·10-3 ] arbitrary units (AU); hyperinsulinaemia, 6.69·10-5 [2.68·10-6 -5.72·10-4 ] AU; P = 0.050). Infusion of iloprost prevented this insulin-induced skeletal muscle capillary derecruitment, from (-49.5 [-89.5 to 55.3] %) to (8.0 [-68.8 to 306.6] %), for conditions without and with iloprost, respectively. The rate of glucose disappearance (Rd ) did not change significantly during iloprost infusion (17.3 [10.0-40.8] μmol/kg/min) compared with insulin infusion alone (17.6 [9.9-68.7] μmol/kg/min). CONCLUSIONS Our data suggest that acute improvement in insulin-stimulated muscle perfusion is not an attractive therapeutic approach to bypass cellular resistance to glucose uptake in type 2 diabetes. Whether long-term improvements in insulin-induced muscle perfusion may prove beneficial for glucose disposal remains to be determined.
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Affiliation(s)
- Anna L Emanuel
- Department of Internal Medicine, VU University Medical Centre, Diabetes Centre, Amsterdam, Netherlands
| | - Nicolien C de Clercq
- Department of Internal Medicine, Academic Medical Centre, Amsterdam, Netherlands
| | - Annefleur M Koopen
- Department of Internal Medicine, Academic Medical Centre, Amsterdam, Netherlands
| | - Erik van Poelgeest
- Department of Internal Medicine, VU University Medical Centre, Diabetes Centre, Amsterdam, Netherlands
| | - Mireille J M Serlie
- Department of Internal Medicine, Academic Medical Centre, Amsterdam, Netherlands
| | - Daniel H van Raalte
- Department of Internal Medicine, VU University Medical Centre, Diabetes Centre, Amsterdam, Netherlands
| | - Mark H H Kramer
- Department of Internal Medicine, VU University Medical Centre, Diabetes Centre, Amsterdam, Netherlands
| | - Max Nieuwdorp
- Department of Internal Medicine, VU University Medical Centre, Diabetes Centre, Amsterdam, Netherlands
- Department of Internal Medicine, Academic Medical Centre, Amsterdam, Netherlands
| | - Etto C Eringa
- Department of Physiology, VU University Medical Centre, Amsterdam, Netherlands
| | - Erik H Serné
- Department of Internal Medicine, VU University Medical Centre, Diabetes Centre, Amsterdam, Netherlands
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Tang H, Yonemitsu I, Ikeda Y, Watakabe K, Shibata S, Hosomichi J, Ono T. Effects of unilateral nasal obstruction on the characteristics of jaw-closing muscles in growing rats. Angle Orthod 2018; 89:102-110. [PMID: 30221984 DOI: 10.2319/021918-132.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Mouth breathing caused by nasal obstruction (owing to abnormal pressure of masticatory muscles) affects craniofacial growth and development. The influence of unilateral nasal obstruction on jaw-closing muscles was investigated in rats to reveal one of the etiologic mechanisms. MATERIALS AND METHODS Forty 8-day-old male Wistar rats were used in this study. Experimental rats were subjected to left-sided nasal obstruction by burning the external nostril tissue at the age of 8 days. Pulse oxygen saturation was recorded each week. Morphologic changes were evaluated by staining with hematoxylin and eosin (to assess the cross-sectional area) and by adenosine triphosphatase activity staining (to assess the myosin heavy chain isoform composition). Immunohistochemical and reverse transcription quantitative real-time polymerase chain reaction analyses of tumor necrosis factor-α and glucose transporter 4 were carried out at 5 and 9 weeks of age. RESULTS The cross-sectional area of the jaw-closing muscles was lower in the experimental group at 9 weeks of age. The percentage of myosin heavy chain-2a in masseter muscles was increased in the experimental group compared with the control group. An increase in the tumor necrosis factor-α messenger RNA and protein levels and a decrease in the glucose transporter 4 messenger RNA and protein levels at 5 and 9 weeks of age in the jaw-closing muscles in the experimental group were noted. CONCLUSIONS Unilateral nasal obstruction could affect the morphology and contractile characteristics of jaw-closing muscles during growth in rats.
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18
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Russell RD, Hu D, Greenaway T, Sharman JE, Rattigan S, Richards SM, Keske MA. Oral glucose challenge impairs skeletal muscle microvascular blood flow in healthy people. Am J Physiol Endocrinol Metab 2018; 315:E307-E315. [PMID: 29763373 DOI: 10.1152/ajpendo.00448.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Skeletal muscle microvascular (capillary) blood flow increases in the postprandial state or during insulin infusion due to dilation of precapillary arterioles to augment glucose disposal. This effect occurs independently of changes in large artery function. However, acute hyperglycemia impairs vascular function, causes insulin to vasoconstrict precapillary arterioles, and causes muscle insulin resistance in vivo. We hypothesized that acute hyperglycemia impairs postprandial muscle microvascular perfusion, without disrupting normal large artery hemodynamics, in healthy humans. Fifteen healthy people (5 F/10 M) underwent an oral glucose challenge (OGC, 50 g glucose) and a mixed-meal challenge (MMC) on two separate occasions (randomized, crossover design). At 1 h, both challenges produced a comparable increase (6-fold) in plasma insulin levels. However, the OGC produced a 1.5-fold higher increase in blood glucose compared with the MMC 1 h postingestion. Forearm muscle microvascular blood volume and flow (contrast-enhanced ultrasound) were increased during the MMC (1.3- and 1.9-fold from baseline, respectively, P < 0.05 for both) but decreased during the OGC (0.7- and 0.6-fold from baseline, respectively, P < 0.05 for both) despite a similar hyperinsulinemia. Both challenges stimulated brachial artery flow (ultrasound) and heart rate to a similar extent, as well as yielding comparable decreases in diastolic blood pressure and total vascular resistance. Systolic blood pressure and aortic stiffness remained unaltered by either challenge. Independently of large artery hemodynamics, hyperglycemia impairs muscle microvascular blood flow, potentially limiting glucose disposal into skeletal muscle. The OGC reduced microvascular blood flow in muscle peripherally and therefore may underestimate the importance of skeletal muscle in postprandial glucose disposal.
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Affiliation(s)
- Ryan D Russell
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
- Department of Health and Human Performance, College of Health Affairs, University of Texas Rio Grande Valley , Brownsville, Texas
| | - Donghua Hu
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
| | - Timothy Greenaway
- Royal Hobart Hospital , Hobart, Tasmania , Australia
- School of Medicine, University of Tasmania , Hobart, Tasmania , Australia
| | - James E Sharman
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
| | - Stephen Rattigan
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
| | - Stephen M Richards
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
- School of Medicine, University of Tasmania , Hobart, Tasmania , Australia
| | - Michelle A Keske
- Menzies Institute for Medical Research, University of Tasmania , Hobart, Tasmania , Australia
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition. Deakin University , Geelong, Victoria , Australia
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Madonna R, Salerni S, Schiavone D, Glatz J, Geng YJ, Caterin R. Omega-3 fatty acids attenuate constitutive and insulin-induced CD36 expression through a suppression of PPARα/γ activity in microvascular endothelial cells. Thromb Haemost 2017; 106:500-10. [DOI: 10.1160/th10-09-0574] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 06/02/2011] [Indexed: 12/31/2022]
Abstract
SummaryMicrovascular dysfunction occurs in insulin resistance and/or hyperinsulinaemia. Enhanced uptake of free fatty acids (FFA) and oxidised low-density lipoproteins (oxLDL) may lead to oxidative stress and microvascular dysfunction interacting with CD36, a PPARα/γ-regulated scavenger receptor and long-chain FFA transporter. We investigated CD36 expression and CD36-mediated oxLDL uptake before and after insulin treatment in human dermal microvascular endothelial cells (HMVECs), ± different types of fatty acids (FA), including palmitic, oleic, linoleic, arachidonic, eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids. Insulin (10−8 and 10−7 M) time-dependently increased DiI-oxLDL uptake and CD36 surface expression (by 30 ± 13%, p<0.05 vs. untreated control after 24 hours incubation), as assessed by ELISA and flow cytometry, an effect that was potentiated by the PI3-kinase inhibitor wortmannin and reverted by the ERK1/2 inhibitor PD98059 and the PPARα/γ antagonist GW9662. A ≥24 hour exposure to 50 μM DHA or EPA, but not other FA, blunted both the constitutive (by 23 ± 3% and 29 ± 2%, respectively, p<0.05 for both) and insulin-induced CD36 expressions (by 45 ± 27 % and 12 ± 3 %, respectively, p<0.05 for both), along with insulin-induced uptake of DiI-oxLDL and the downregulation of phosphorylated endothelial nitric oxide synthase (P-eNOS). At gel shift assays, DHA reverted insulin-induced basal and oxLDL-stimulated transactivation of PPRE and DNA binding of PPARα/γ and NF-κB. In conclusion, omega-3 fatty acids blunt the increased CD36 expression and activity promoted by high concentrations of insulin. Such mechanisms may be the basis for the use of omega-3 fatty acids in diabetic microvasculopathy.
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Dion F, Dumayne C, Henley N, Beauchemin S, Arias EB, Leblond FA, Lesage S, Lefrançois S, Cartee GD, Pichette V. Mechanism of insulin resistance in a rat model of kidney disease and the risk of developing type 2 diabetes. PLoS One 2017; 12:e0176650. [PMID: 28459862 PMCID: PMC5411038 DOI: 10.1371/journal.pone.0176650] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/13/2017] [Indexed: 12/19/2022] Open
Abstract
Chronic kidney disease is associated with homeostatic imbalances such as insulin resistance. However, the underlying mechanisms leading to these imbalances and whether they promote the development of type 2 diabetes is unknown. The effect of chronic kidney disease on insulin resistance was studied on two different rat strains. First, in a 5/6th nephrectomised Sprague-Dawley rat model of chronic kidney disease, we observed a correlation between the severity of chronic kidney disease and hyperglycemia as evaluated by serum fructosamine levels (p<0.0001). Further, glucose tolerance tests indicated an increase of 25% in glycemia in chronic kidney disease rats (p<0.0001) as compared to controls whereas insulin levels remained unchanged. We also observed modulation of glucose transporters expression in several tissues such as the liver (decrease of ≈40%, p≤0.01) and muscles (decrease of ≈29%, p≤0.05). Despite a significant reduction of ≈37% in insulin-dependent glucose uptake in the muscles of chronic kidney disease rats (p<0.0001), the development of type 2 diabetes was never observed. Second, in a rat model of metabolic syndrome (Zucker Leprfa/fa), chronic kidney disease caused a 50% increased fasting hyperglycemia (p<0.0001) and an exacerbated glycemic response (p<0.0001) during glucose challenge. Similar modulations of glucose transporters expression and glucose uptake were observed in the two models. However, 30% (p<0.05) of chronic kidney disease Zucker rats developed characteristics of type 2 diabetes. Thus, our results suggest that downregulation of GLUT4 in skeletal muscle may be associated with insulin resistance in chronic kidney disease and could lead to type 2 diabetes in predisposed animals.
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Affiliation(s)
- François Dion
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
- Département de pharmacologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
- * E-mail: (VP); (FD)
| | - Christopher Dumayne
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
- Département de pharmacologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Nathalie Henley
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
| | - Stéphanie Beauchemin
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
| | - Edward B. Arias
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - François A. Leblond
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
| | - Sylvie Lesage
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Stéphane Lefrançois
- Centre INRS-Institut Armand-Frappier, Institut National de la Recherche Scientifique, Laval, Québec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Gregory D. Cartee
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Vincent Pichette
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
- Département de pharmacologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
- * E-mail: (VP); (FD)
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Emanuel AL, Meijer RI, Muskiet MHA, van Raalte DH, Eringa EC, Serné EH. Role of Insulin-Stimulated Adipose Tissue Perfusion in the Development of Whole-Body Insulin Resistance. Arterioscler Thromb Vasc Biol 2017; 37:411-418. [PMID: 28126826 DOI: 10.1161/atvbaha.116.308670] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/17/2017] [Indexed: 01/08/2023]
Abstract
After food ingestion, macronutrients are transported to and stored in the skeletal muscle and adipose tissue. They can be subsequently used as an energy source in times of energy deprivation. Uptake of these nutrients in myocytes and adipocytes depends largely on adequate tissue perfusion. Interestingly, insulin is able to dilate skeletal muscle arterioles, which facilitates the delivery of macronutrients and insulin itself to muscle tissue. Insulin-stimulated skeletal muscle perfusion is impaired in several insulin-resistant states and is believed to contribute to impaired skeletal muscle glucose uptake and consequently impaired whole-body glucose disposal. Insulin-resistant individuals also exhibit blunted postprandial adipose tissue perfusion. However, the relevance of this impairment to metabolic dysregulation is less clear. In this review, we provide an overview of adipose tissue perfusion in healthy and insulin-resistant individuals, its regulation among others by insulin, and the possible influences of impaired adipose tissue perfusion on whole-body insulin sensitivity. Finally, we propose a novel hypothesis that acute overfeeding impacts distribution of macronutrients by reducing skeletal muscle perfusion, while adipose tissue perfusion remains intact. VISUAL OVERVIEW An online visual overview is available for this article.
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Affiliation(s)
- Anna L Emanuel
- From the Departments of Internal Medicine (A.L.E., R.I.M., M.H.A.M., D.H.v.R., E.H.S.) and Physiology (E.C.E.), VU University Medical Center, Amsterdam.
| | - Rick I Meijer
- From the Departments of Internal Medicine (A.L.E., R.I.M., M.H.A.M., D.H.v.R., E.H.S.) and Physiology (E.C.E.), VU University Medical Center, Amsterdam
| | - Marcel H A Muskiet
- From the Departments of Internal Medicine (A.L.E., R.I.M., M.H.A.M., D.H.v.R., E.H.S.) and Physiology (E.C.E.), VU University Medical Center, Amsterdam
| | - Daniël H van Raalte
- From the Departments of Internal Medicine (A.L.E., R.I.M., M.H.A.M., D.H.v.R., E.H.S.) and Physiology (E.C.E.), VU University Medical Center, Amsterdam
| | - Etto C Eringa
- From the Departments of Internal Medicine (A.L.E., R.I.M., M.H.A.M., D.H.v.R., E.H.S.) and Physiology (E.C.E.), VU University Medical Center, Amsterdam
| | - Erik H Serné
- From the Departments of Internal Medicine (A.L.E., R.I.M., M.H.A.M., D.H.v.R., E.H.S.) and Physiology (E.C.E.), VU University Medical Center, Amsterdam
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Keske MA, Dwyer RM, Russell RD, Blackwood SJ, Brown AA, Hu D, Premilovac D, Richards SM, Rattigan S. Regulation of microvascular flow and metabolism: An overview. Clin Exp Pharmacol Physiol 2016; 44:143-149. [DOI: 10.1111/1440-1681.12688] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/07/2016] [Accepted: 10/21/2016] [Indexed: 01/12/2023]
Affiliation(s)
- Michelle A Keske
- Menzies Institute for Medical Research University of Tasmania Hobart Tas. Australia
| | - Renee M Dwyer
- School of Medicine University of Tasmania Hobart Tas. Australia
| | - Ryan D Russell
- Menzies Institute for Medical Research University of Tasmania Hobart Tas. Australia
| | - Sarah J Blackwood
- Menzies Institute for Medical Research University of Tasmania Hobart Tas. Australia
| | - Aascha A Brown
- Menzies Institute for Medical Research University of Tasmania Hobart Tas. Australia
| | - Donghua Hu
- Menzies Institute for Medical Research University of Tasmania Hobart Tas. Australia
| | - Dino Premilovac
- School of Medicine University of Tasmania Hobart Tas. Australia
| | | | - Stephen Rattigan
- Menzies Institute for Medical Research University of Tasmania Hobart Tas. Australia
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Röhling M, Herder C, Stemper T, Müssig K. Influence of Acute and Chronic Exercise on Glucose Uptake. J Diabetes Res 2016; 2016:2868652. [PMID: 27069930 PMCID: PMC4812462 DOI: 10.1155/2016/2868652] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/31/2016] [Accepted: 02/03/2016] [Indexed: 02/06/2023] Open
Abstract
Insulin resistance plays a key role in the development of type 2 diabetes. It arises from a combination of genetic predisposition and environmental and lifestyle factors including lack of physical exercise and poor nutrition habits. The increased risk of type 2 diabetes is molecularly based on defects in insulin signaling, insulin secretion, and inflammation. The present review aims to give an overview on the molecular mechanisms underlying the uptake of glucose and related signaling pathways after acute and chronic exercise. Physical exercise, as crucial part in the prevention and treatment of diabetes, has marked acute and chronic effects on glucose disposal and related inflammatory signaling pathways. Exercise can stimulate molecular signaling pathways leading to glucose transport into the cell. Furthermore, physical exercise has the potential to modulate inflammatory processes by affecting specific inflammatory signaling pathways which can interfere with signaling pathways of the glucose uptake. The intensity of physical training appears to be the primary determinant of the degree of metabolic improvement modulating the molecular signaling pathways in a dose-response pattern, whereas training modality seems to have a secondary role.
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Affiliation(s)
- Martin Röhling
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Munich, 85764 Neuherberg, Germany
| | - Christian Herder
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Munich, 85764 Neuherberg, Germany
| | - Theodor Stemper
- Department Fitness and Health, University Wuppertal, 42119 Wuppertal, Germany
| | - Karsten Müssig
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Munich, 85764 Neuherberg, Germany
- Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
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Sabanayagam C, Lye WK, Klein R, Klein BEK, Cotch MF, Wang JJ, Mitchell P, Shaw JE, Selvin E, Sharrett AR, Wong TY. Retinal microvascular calibre and risk of diabetes mellitus: a systematic review and participant-level meta-analysis. Diabetologia 2015; 58:2476-85. [PMID: 26232097 PMCID: PMC4751991 DOI: 10.1007/s00125-015-3717-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/08/2015] [Indexed: 12/26/2022]
Abstract
AIMS/HYPOTHESIS The calibre of the retinal vessels has been linked to diabetes mellitus but studies have not shown consistent results. We conducted a participant-level meta-analysis to evaluate the association between retinal arteriolar and venular calibre and diabetes. METHODS We performed a systematic review on MEDLINE and EMBASE for articles published up to December 2014. We identified five population-based prospective cohort studies that provided individual-level data on 18,771 diabetes-free participants. We used discrete time proportional hazards models to estimate pooled HRs of diabetes associated with 1 SD (20 μm) change in retinal vascular calibre. RESULTS We identified 2,581 incident cases of diabetes over a median follow-up period of 10 years (interquartile interval of 3.4-15.8 years). After adjustment for demographic, lifestyle and clinical factors, retinal venular calibre was significantly associated with incident diabetes (pooled HR 1.09 [95% CI 1.02, 1.15] per SD increase in venular calibre). This association persisted in analyses excluding individuals with <5 years of follow-up (1.07 [1.0, 1.12]) or those with impaired fasting glucose at baseline (1.10 [1.03, 1.17]); in subgroup analyses, the association was stronger in men than in women but was consistent across subgroups of race/ethnicity, smoking status, hypertension and BMI categories. Retinal arteriolar calibre was not associated with diabetes (0.95 [0.86, 1.06] per SD decrease in arteriolar calibre). CONCLUSIONS/INTERPRETATION Wider retinal venules but not narrower retinal arterioles were associated with a modestly increased risk for diabetes. Knowledge of pathological mechanisms underlying wider retinal venule may provide further insights concerning microvascular alterations in diabetes.
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Affiliation(s)
- Charumathi Sabanayagam
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Republic of Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore, Republic of Singapore
- Department of Ophthalmology, National University of Singapore, Singapore, Republic of Singapore
| | - Weng Kit Lye
- Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore, Republic of Singapore
| | - Ronald Klein
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Barbara E K Klein
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Mary Frances Cotch
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jie Jin Wang
- Department of Ophthalmology and Westmead Millennium Institute, Centre for Vision Research, University of Sydney, Sydney, NSW, Australia
| | - Paul Mitchell
- Department of Ophthalmology and Westmead Millennium Institute, Centre for Vision Research, University of Sydney, Sydney, NSW, Australia
| | - Jonathan E Shaw
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Elizabeth Selvin
- Department of Epidemiology, John Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - A Richey Sharrett
- Department of Epidemiology, John Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Tien Y Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Republic of Singapore.
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore, Republic of Singapore.
- Department of Ophthalmology, National University of Singapore, Singapore, Republic of Singapore.
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Inflammation-induced microvascular insulin resistance is an early event in diet-induced obesity. Clin Sci (Lond) 2015; 129:1025-36. [PMID: 26265791 PMCID: PMC4613534 DOI: 10.1042/cs20150143] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 08/11/2015] [Indexed: 01/04/2023]
Abstract
Obesity and diabetes are associated with inflammation, endothelial dysfunction and insulin resistance in the muscle microvasculature. Inflammation-induced microvascular insulin resistance is an early event and plays a causative role in the development of metabolic insulin resistance in diet-induced obesity. Endothelial dysfunction and vascular insulin resistance usually coexist and chronic inflammation engenders both. In the present study, we investigate the temporal relationship between vascular insulin resistance and metabolic insulin resistance. We assessed insulin responses in all arterial segments, including aorta, distal saphenous artery and the microvasculature, as well as the metabolic insulin responses in muscle in rats fed on a high-fat diet (HFD) for various durations ranging from 3 days to 4 weeks with or without sodium salicylate treatment. Compared with controls, HFD feeding significantly blunted insulin-mediated Akt (protein kinase B) and eNOS [endothelial nitric oxide (NO) synthase] phosphorylation in aorta in 1 week, blunted vasodilatory response in small resistance vessel in 4 weeks and microvascular recruitment in as early as 3 days. Insulin-stimulated whole body glucose disposal did not begin to progressively decrease until after 1 week. Salicylate treatment fully inhibited vascular inflammation, prevented microvascular insulin resistance and significantly improved muscle metabolic responses to insulin. We conclude that microvascular insulin resistance is an early event in diet-induced obesity and insulin resistance and inflammation plays an essential role in this process. Our data suggest microvascular insulin resistance contributes to the development of metabolic insulin resistance in muscle and muscle microvasculature is a potential therapeutic target in the prevention and treatment of diabetes and its related complications.
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26
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Keske MA, Ng HLH, Premilovac D, Rattigan S, Kim JA, Munir K, Yang P, Quon MJ. Vascular and metabolic actions of the green tea polyphenol epigallocatechin gallate. Curr Med Chem 2015; 22:59-69. [PMID: 25312214 PMCID: PMC4909506 DOI: 10.2174/0929867321666141012174553] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/05/2014] [Accepted: 08/05/2014] [Indexed: 01/04/2023]
Abstract
Epidemiological studies demonstrate robust correlations between green tea consumption and reduced risk of type 2 diabetes and its cardiovascular complications. However, underlying molecular, cellular, and physiological mechanisms remain incompletely understood. Health promoting actions of green tea are often attributed to epigallocatechin gallate (EGCG), the most abundant polyphenol in green tea. Insulin resistance and endothelial dysfunction play key roles in the pathogenesis of type 2 diabetes and its cardiovascular complications. Metabolic insulin resistance results from impaired insulin-mediated glucose disposal in skeletal muscle and adipose tissue, and blunted insulin-mediated suppression of hepatic glucose output that is often associated with endothelial/vascular dysfunction. This endothelial dysfunction is itself caused, in part, by impaired insulin signaling in vascular endothelium resulting in reduced insulin-stimulated production of NO in arteries, and arterioles that regulate nutritive capillaries. In this review, we discuss the considerable body of literature supporting insulin-mimetic actions of EGCG that oppose endothelial dysfunction and ameliorate metabolic insulin resistance in skeletal muscle and liver. We conclude that EGCG is a promising therapeutic to combat cardiovascular complications associated with the metabolic diseases characterized by reciprocal relationships between insulin resistance and endothelial dysfunction that include obesity, metabolic syndrome and type 2 diabetes. There is a strong rationale for well-powered randomized placebo controlled intervention trials to be carried out in insulin resistant and diabetic populations.
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Affiliation(s)
| | | | | | | | | | | | | | - Michael J Quon
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, 7000, Australia.
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27
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Zheng C, Liu Z. Vascular function, insulin action, and exercise: an intricate interplay. Trends Endocrinol Metab 2015; 26:297-304. [PMID: 25735473 PMCID: PMC4450131 DOI: 10.1016/j.tem.2015.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/29/2015] [Accepted: 02/03/2015] [Indexed: 01/04/2023]
Abstract
Insulin enhances the compliance of conduit arteries, relaxes resistance arterioles to increase tissue blood flow, and dilates precapillary arterioles to expand muscle microvascular blood volume. These actions are impaired in the insulin resistant states. Exercise ameliorates endothelial dysfunction and improves insulin responses in insulin resistant patients, but the precise underlying mechanisms remain unclear. The microvasculature critically regulates insulin action in muscle by modulating insulin delivery to the capillaries nurturing the myocytes and trans-endothelial insulin transport. Recent data suggest that exercise may exert its insulin-sensitizing effect via recruiting muscle microvasculature to increase insulin delivery to and action in muscle. The current review focuses on how the interplay among exercise, insulin action, and the vasculature contributes to exercise-mediated insulin sensitization in muscle.
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Affiliation(s)
- Chao Zheng
- Diabetes Center and Department of Endocrinology, the Second Affiliated Hospital of Wenzhou Medical University, Zhejiang, China
| | - Zhenqi Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA.
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28
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Tissue inflammation and nitric oxide-mediated alterations in cardiovascular function are major determinants of endotoxin-induced insulin resistance. Cardiovasc Diabetol 2015; 14:56. [PMID: 25986700 PMCID: PMC4484635 DOI: 10.1186/s12933-015-0223-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/05/2015] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Endotoxin (i.e. LPS) administration induces a robust inflammatory response with accompanying cardiovascular dysfunction and insulin resistance. Overabundance of nitric oxide (NO) contributes to the vascular dysfunction. However, inflammation itself also induces insulin resistance in skeletal muscle. We sought to investigate whether the cardiovascular dysfunction induced by increased NO availability without inflammatory stress can promote insulin resistance. Additionally, we examined the role of inducible nitric oxide synthase (iNOS or NOS2), the source of the increase in NO availability, in modulating LPS-induced decrease in insulin-stimulated muscle glucose uptake (MGU). METHODS The impact of NO donor infusion on insulin-stimulated whole-body and muscle glucose uptake (hyperinsulinemic-euglycemic clamps), and the cardiovascular system was assessed in chronically catheterized, conscious mice wild-type (WT) mice. The impact of LPS on insulin action and the cardiovascular system were assessed in WT and global iNOS knockout (KO) mice. Tissue blood flow and cardiac function were assessed using microspheres and echocardiography, respectively. Insulin signaling activity, and gene expression of pro-inflammatory markers were also measured. RESULTS NO donor infusion decreased mean arterial blood pressure, whole-body glucose requirements, and MGU in the absence of changes in skeletal muscle blood flow. LPS lowered mean arterial blood pressure and glucose requirements in WT mice, but not in iNOS KO mice. Lastly, despite an intact inflammatory response, iNOS KO mice were protected from LPS-mediated deficits in cardiac output. LPS impaired MGU in vivo, regardless of the presence of iNOS. However, ex vivo, insulin action in muscle obtained from LPS treated iNOS KO animals was protected. CONCLUSION Nitric oxide excess and LPS impairs glycemic control by diminishing MGU. LPS impairs MGU by both the direct effect of inflammation on the myocyte, as well as by the indirect NO-driven cardiovascular dysfunction.
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29
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Keske MA, Premilovac D, Bradley EA, Dwyer RM, Richards SM, Rattigan S. Muscle microvascular blood flow responses in insulin resistance and ageing. J Physiol 2015; 594:2223-31. [PMID: 25581640 DOI: 10.1113/jphysiol.2014.283549] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 12/08/2014] [Indexed: 12/18/2022] Open
Abstract
Insulin resistance plays a key role in the development of type 2 diabetes. Skeletal muscle is the major storage site for glucose following a meal and as such has a key role in maintenance of blood glucose concentrations. Insulin resistance is characterised by impaired insulin-mediated glucose disposal in skeletal muscle. Multiple mechanisms can contribute to development of muscle insulin resistance and our research has demonstrated an important role for loss of microvascular function within skeletal muscle. We have shown that insulin can enhance blood flow to the microvasculature in muscle thus improving the access of glucose and insulin to the myocytes to augment glucose disposal. Obesity, insulin resistance and ageing are all associated with impaired microvascular responses to insulin in skeletal muscle. Impairments in insulin-mediated microvascular perfusion in muscle can directly cause insulin resistance, and this event can occur early in the aetiology of this condition. Understanding the mechanisms involved in the loss of microvascular function in muscle has the potential to identify novel treatment strategies to prevent or delay progression of insulin resistance and type 2 diabetes.
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Affiliation(s)
- Michelle A Keske
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Dino Premilovac
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia.,School of Medicine, University of Tasmania, Hobart, Australia
| | - Eloise A Bradley
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Renee M Dwyer
- School of Medicine, University of Tasmania, Hobart, Australia
| | | | - Stephen Rattigan
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
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30
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Akerstrom T, Laub L, Vedel K, Brand CL, Pedersen BK, Lindqvist AK, Wojtaszewski JFP, Hellsten Y. Increased skeletal muscle capillarization enhances insulin sensitivity. Am J Physiol Endocrinol Metab 2014; 307:E1105-16. [PMID: 25352432 DOI: 10.1152/ajpendo.00020.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Increased skeletal muscle capillarization is associated with improved glucose tolerance and insulin sensitivity. However, a possible causal relationship has not previously been identified. Therefore, we investigated whether increased skeletal muscle capillarization increases insulin sensitivity. Skeletal muscle-specific angiogenesis was induced by adding the α1-adrenergic receptor antagonist prazosin to the drinking water of Sprague-Dawley rats (n = 33), whereas 34 rats served as controls. Insulin sensitivity was measured ≥40 h after termination of the 3-wk prazosin treatment, which ensured that prazosin was cleared from the blood stream. Whole body insulin sensitivity was measured in conscious, unrestrained rats by hyperinsulinemic euglycemic clamp. Tissue-specific insulin sensitivity was assessed by administration of 2-deoxy-[(3)H]glucose during the plateau phase of the clamp. Whole body insulin sensitivity increased by ∼24%, and insulin-stimulated skeletal muscle 2-deoxy-[(3)H]glucose disposal increased by ∼30% concomitant with an ∼20% increase in skeletal muscle capillarization. Adipose tissue insulin sensitivity was not affected by the treatment. Insulin-stimulated muscle glucose uptake was enhanced independent of improvements in skeletal muscle insulin signaling to glucose uptake and glycogen synthesis, suggesting that the improvement in insulin-stimulated muscle glucose uptake could be due to improved diffusion conditions for glucose in the muscle. The prazosin treatment did not affect the rats on any other parameters measured. We conclude that an increase in skeletal muscle capillarization is associated with increased insulin sensitivity. These data point toward the importance of increasing skeletal muscle capillarization for prevention or treatment of type 2 diabetes.
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Affiliation(s)
- Thorbjorn Akerstrom
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark;
| | - Lasse Laub
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Kenneth Vedel
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | | | - Bente Klarlund Pedersen
- Centre of Inflammation and Metabolism at the Department of Infectious Diseases and Copenhagen Muscle Research Centre, Rigshospitalet and Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna Kaufmann Lindqvist
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Ylva Hellsten
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
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31
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Premilovac D, Richards SM, Rattigan S, Keske MA. A vascular mechanism for high-sodium-induced insulin resistance in rats. Diabetologia 2014; 57:2586-95. [PMID: 25212260 DOI: 10.1007/s00125-014-3373-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/18/2014] [Indexed: 10/24/2022]
Abstract
AIMS/HYPOTHESIS High sodium (HS) effects on hypertension are well established. Recent evidence implicates a relationship between HS intake and insulin resistance, even in the absence of hypertension. The aim of the current study was to determine whether loss of the vascular actions of insulin may be the driving factor linking HS intake to insulin resistance. METHODS Sprague Dawley rats were fed a control (0.31% wt/wt NaCl) or HS (8.00% wt/wt NaCl) diet for 4 weeks and subjected to euglycaemic-hyperinsulinaemic clamp (10 mU min(-1) kg(-1)) or constant-flow pump-perfused hindlimb studies following an overnight fast. A separate group of HS rats was given quinapril during the dietary intervention and subjected to euglycaemic-hyperinsulinaemic clamp as above. RESULTS HS intake had no effect on body weight or fat mass or on fasting glucose, insulin, endothelin-1 or NEFA concentrations. However, HS impaired whole body and skeletal muscle glucose uptake, in addition to a loss of insulin-stimulated microvascular recruitment. These effects were present despite enhanced insulin signalling (Akt) in both liver and skeletal muscle. Constant-flow pump-perfused hindlimb experiments revealed normal insulin-stimulated myocyte glucose uptake in HS-fed rats. Quinapril treatment restored insulin-mediated microvascular recruitment and muscle glucose uptake in vivo. CONCLUSIONS/INTERPRETATION HS-induced insulin resistance is driven by impaired microvascular responsiveness to insulin, and is not due to metabolic or signalling defects within myocytes or liver. These results imply that reducing sodium intake may be important not only for management of hypertension but also for insulin resistance, and highlight the vasculature as a potential therapeutic target in the prevention of insulin resistance.
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Affiliation(s)
- Dino Premilovac
- Menzies Research Institute Tasmania, University of Tasmania, 17 Liverpool Street, Hobart, TAS, 7000, Australia
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32
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Zhao L, Fu Z, Liu Z. Adiponectin and insulin cross talk: the microvascular connection. Trends Cardiovasc Med 2014; 24:319-24. [PMID: 25220977 DOI: 10.1016/j.tcm.2014.08.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/02/2014] [Accepted: 08/03/2014] [Indexed: 12/20/2022]
Abstract
Adiponectin exerts both vasodilatory and insulin-sensitizing actions and its levels are decreased in insulin-resistant humans and animals. The mechanisms underlying adiponectin׳s insulin-sensitizing effect have been extensively investigated but remain largely unclear. Muscle microvasculature critically regulates muscle insulin action by modulating insulin delivery to the microvessels nurturing the muscle cells and the trans-endothelial insulin transport. We have recently reported that adiponectin exerts its insulin-sensitizing effect via recruiting muscle microvasculature, expanding the endothelial surface area, and increasing insulin delivery to and thus action in muscle. The current review focuses on the microvascular connection between the adiponectin and insulin cross talk.
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Affiliation(s)
- Lina Zhao
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, PO Box 801410, Charlottesville, VA 22908
| | - Zhuo Fu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, PO Box 801410, Charlottesville, VA 22908
| | - Zhenqi Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, PO Box 801410, Charlottesville, VA 22908.
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Abstract
There is growing recognition that obesity is reaching epidemic proportions throughout the world. In adults, obesity is associated with increased cardiovascular morbidity and mortality. A series of endocrine, metabolic and hemodynamic mechanisms have been responsible for the development of obesity-hypertension. These mechanisms include: a suppressed biologic activity and availability of natriuretic peptide, increased sympathetic adrenergic activity, release of angiotensin ll from adipocytes and activation of the renin-angiotensin-aldosterone system, leptin resistance, chronic hyperleptinemia and hyperinsulinemia. The systemic hemodynamic profile of obesity includes high intravascular volume, increased cardiac output and inappropriately normal peripheral resistance. The cardiovascular adaptations to these changes include changes in vascular responsiveness and concentric-eccentric left ventricular hypertrophy, and may be responsible for increased risk of congestive heart failure, arrhythmia and sudden death.
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Affiliation(s)
- Stephen A Morse
- Louisiana State University Health Sciences Center, Section of Nephrology, Department of Medicine, New Orleans, LA 70112, USA
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34
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Bradley EA, Richards SM, Keske MA, Rattigan S. Local NOS inhibition impairs vascular and metabolic actions of insulin in rat hindleg muscle in vivo. Am J Physiol Endocrinol Metab 2013; 305:E745-50. [PMID: 23900417 DOI: 10.1152/ajpendo.00289.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin stimulates microvascular recruitment in skeletal muscle, and this vascular action augments muscle glucose disposal by ∼40%. The aim of the current study was to determine the contribution of local nitric oxide synthase (NOS) to the vascular actions of insulin in muscle. Hooded Wistar rats were infused with the NOS inhibitor N(ω)-nitro-L-arginine methylester (L-NAME, 10 μM) retrogradely via the epigastric artery in one leg during a systemic hyperinsulinemic-euglycemic clamp (3 mU·min(-1)·kg(-1) × 60 min) or saline infusion. Femoral artery blood flow, microvascular blood flow (assessed from 1-methylxanthine metabolism), and muscle glucose uptake (2-deoxyglucose uptake) were measured in both legs. Local L-NAME infusion did not have any systemic actions on blood pressure or heart rate. Local L-NAME blocked insulin-stimulated changes in femoral artery blood flow (84%, P < 0.05) and microvascular recruitment (98%, P < 0.05), and partially blocked insulin-mediated glucose uptake in muscle (reduced by 34%, P < 0.05). L-NAME alone did not have any metabolic effects in the hindleg. We conclude that insulin-mediated microvascular recruitment is dependent on local activation of NOS in muscle and that this action is important for insulin's metabolic actions.
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Affiliation(s)
- Eloise A Bradley
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Australia
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35
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Tishinsky JM, De Boer AA, Dyck DJ, Robinson LE. Modulation of visceral fat adipokine secretion by dietary fatty acids and ensuing changes in skeletal muscle inflammation. Appl Physiol Nutr Metab 2013; 39:28-37. [PMID: 24383504 DOI: 10.1139/apnm-2013-0135] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Given the link between obesity and insulin resistance, the role of adipose-derived factors in communicating with skeletal muscle to affect its function is important. We sought to determine if high fat diets modulate visceral adipose tissue (VAT) adipokines with subsequent effects on skeletal muscle inflammation and insulin sensitivity. Rats were fed (i) low fat (LF), (ii) high saturated fatty acid (SFA), or (iii) high SFA with n-3 polyunsaturated fatty acid (SFA/n-3 PUFA) diets for 4 weeks. VAT-derived adipokines were measured in adipose conditioned medium (ACM) after 72 h. Next, skeletal muscles from LF-fed rats were incubated for 8 h in (i) control buffer (CON), (ii) CON with 2 mmol·L(-1) palmitate (PALM, positive control), (iii) ACM from LF, (iv) ACM from SFA, or (v) ACM from SFA/n-3 PUFA. ACM from rats fed SFA and SFA/n-3 PUFA had increased (P ≤ 0.05) interleukin-6 (IL-6) (+31%) and monocyte chemoattractant protein-1 (MCP-1) (+30%). Adiponectin was decreased (-29%, P ≤ 0.05) in ACM from SFA, and this was prevented in SFA/n-3 PUFA ACM. Toll-like receptor 4 (TLR4) gene expression was increased (P ≤ 0.05) in PALM soleus muscle (+356%) and all ACM groups (+175%-191%). MCP-1 gene expression was elevated (P ≤ 0.05) in PALM soleus muscle (+163%) and soleus muscle incubated in ACM from animals fed SFA (+159%) and SFA/n-3 PUFA (+151%). Glucose transport was impaired (P ≤ 0.05) in PALM muscles but preserved in ACM groups. Acute exposure of muscle to fatty acid modulated adipokines affects skeletal muscle inflammatory gene expression but not insulin sensitivity.
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Affiliation(s)
- Justine M Tishinsky
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
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Kubota T, Kubota N, Kadowaki T. The role of endothelial insulin signaling in the regulation of glucose metabolism. Rev Endocr Metab Disord 2013; 14:207-16. [PMID: 23589150 DOI: 10.1007/s11154-013-9242-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The skeletal muscle is one of the major target organs of insulin and plays an essential role in insulin-induced glucose uptake. Some evidence indicates that insulin delivery to skeletal muscle interstitium through the endothelial cells is the rate-limiting step in insulin-stimulated glucose uptake. Researchers have also found that this process is impaired by insulin resistance in type 2 diabetes and obesity. A recent study of ours demonstrated that insulin signaling in the endothelial cells plays a pivotal role in the regulation of glucose uptake by the skeletal muscle. Specifically, impaired insulin signaling in the endothelial cells, with reduction of insulin-induced eNOS phosphorylation, causes attenuation of the insulin-induced capillary recruitment and insulin delivery, which, in turn reduces glucose uptake by the skeletal muscle in high-fat diet-fed mice. Moreover, restoration of the insulin-induced eNOS phosphorylation in the endothelial cells completely reverses the reduction in the capillary recruitment and insulin delivery, and as a result, significantly restores glucose uptake by the skeletal muscle. In the present review, we describe the recent progress in research on the physiological and pathophysiological roles of endothelial insulin signaling in the regulation of insulin-induced glucose uptake by the skeletal muscle.
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Affiliation(s)
- Tetsuya Kubota
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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Wang N, Chai W, Zhao L, Tao L, Cao W, Liu Z. Losartan increases muscle insulin delivery and rescues insulin's metabolic action during lipid infusion via microvascular recruitment. Am J Physiol Endocrinol Metab 2013; 304:E538-45. [PMID: 23299501 PMCID: PMC3602659 DOI: 10.1152/ajpendo.00537.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin delivery and transendothelial insulin transport are two discrete steps that limit muscle insulin action. Angiotensin II type 1 receptor (AT1R) blockade recruits microvasculature and increases glucose use in muscle. Increased muscle microvascular perfusion is associated with increased muscle delivery and action of insulin. To examine the effect of acute AT1R blockade on muscle insulin uptake and action, rats were studied after an overnight fast to examine the effects of losartan on muscle insulin uptake (protocol 1), microvascular perfusion (protocol 2), and insulin's microvascular and metabolic actions in the state of insulin resistance (protocol 3). Endothelial cell insulin uptake was assessed, using (125)I-insulin as tracer. Systemic lipid infusion was used to induce insulin resistance. Losartan significantly increased muscle insulin uptake (∼60%, P < 0.03), which was associated with a two- to threefold increase in muscle microvascular blood volume (MBV; P = 0.002) and flow (MBF; P = 0.002). Losartan ± angiotensin II had no effect on insulin internalization in cultured endothelial cells. Lipid infusion abolished insulin-mediated increases in muscle MBV and MBF and lowered insulin-stimulated whole body glucose disposal (P = 0.0001), which were reversed by losartan administration. Inhibition of nitric oxide synthase abolished losartan-induced muscle insulin uptake and reversal of lipid-induced metabolic insulin resistance. We conclude that AT1R blockade increases muscle insulin uptake mainly via microvascular recruitment and rescues insulin's metabolic action in the insulin-resistant state. This may contribute to the clinical findings of decreased cardiovascular events and new onset of diabetes in patients receiving AT1R blockers.
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Affiliation(s)
- Nasui Wang
- Div. of Endocrinology and Metabolism, Dept. of Medicine, Univ. of Virginia Health System, Charlottesville, VA 22908, USA
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Muris DMJ, Houben AJHM, Schram MT, Stehouwer CDA. Microvascular dysfunction: an emerging pathway in the pathogenesis of obesity-related insulin resistance. Rev Endocr Metab Disord 2013; 14:29-38. [PMID: 23299657 DOI: 10.1007/s11154-012-9231-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The prevalence of type 2 diabetes mellitus (T2DM) and its major risk factor, obesity, has reached epidemic proportions in Western society. How obesity leads to insulin resistance and subsequent T2DM is incompletely understood. It has been established that insulin can redirect blood flow in skeletal muscle from non-nutritive to nutritive capillary networks, without increasing total blood flow. This results in a net increase of the overall number of perfused nutritive capillary networks and thereby increases insulin-mediated glucose uptake by skeletal muscle. This process, referred to as functional (nutritive) capillary recruitment, has been shown to be endothelium-dependent and to require activation of the phosphatidylinositol-kinase (PI3K) pathway in the endothelial cell. Several studies have demonstrated that these processes are impaired in states of microvascular dysfunction. In obesity, changes in several adipokines are likely candidates to influence insulin signaling pathways in endothelial cells, thereby causing microvascular dysfunction. Microvascular dysfunction, in turn, impairs the timely access of glucose and insulin to their target tissues, and may therefore be an additional cause of insulin resistance. Thus, microvascular dysfunction may be a key feature in the development of obesity-related insulin resistance. In the present review, we will discuss the evidence for this emerging role for the microcirculation as a possible link between obesity and insulin resistance.
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Affiliation(s)
- Dennis M J Muris
- Department of Internal Medicine, Maastricht University Medical Centre (MUMC+), P.O. Box 5800, 6202 AZ, Maastricht, the Netherlands
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Meijer RI, Bakker W, Alta CLA, Sipkema P, Yudkin JS, Viollet B, Richter EA, Smulders YM, van Hinsbergh VW, Serné EH, Eringa EC. Perivascular adipose tissue control of insulin-induced vasoreactivity in muscle is impaired in db/db mice. Diabetes 2013; 62:590-8. [PMID: 23048187 PMCID: PMC3554353 DOI: 10.2337/db11-1603] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Microvascular recruitment in muscle is a determinant of insulin sensitivity. Whether perivascular adipose tissue (PVAT) is involved in disturbed insulin-induced vasoreactivity is unknown, as are the underlying mechanisms. This study investigates whether PVAT regulates insulin-induced vasodilation in muscle, the underlying mechanisms, and how obesity disturbs this vasodilation. Insulin-induced vasoreactivity of resistance arteries was studied with PVAT from C57BL/6 or db/db mice. PVAT weight in muscle was higher in db/db mice compared with C57BL/6 mice. PVAT from C57BL/6 mice uncovered insulin-induced vasodilation; this vasodilation was abrogated with PVAT from db/db mice. Blocking adiponectin abolished the vasodilator effect of insulin in the presence of C57BL/6 PVAT, and adiponectin secretion was lower in db/db PVAT. To investigate this interaction further, resistance arteries of AMPKα2(+/+) and AMPKα2(-/-) were studied. In AMPKα2(-/-) resistance arteries, insulin caused vasoconstriction in the presence of PVAT, and AMPKα2(+/+) resistance arteries showed a neutral response. On the other hand, inhibition of the inflammatory kinase Jun NH(2)-terminal kinase (JNK) in db/db PVAT restored insulin-induced vasodilation in an adiponectin-dependent manner. In conclusion, PVAT controls insulin-induced vasoreactivity in the muscle microcirculation through secretion of adiponectin and subsequent AMPKα2 signaling. PVAT from obese mice inhibits insulin-induced vasodilation, which can be restored by inhibition of JNK.
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Affiliation(s)
- Rick I. Meijer
- Department of Internal Medicine, VU University Medical Center, Amsterdam, the Netherlands
- Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Wineke Bakker
- Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Caro-Lynn A.F. Alta
- Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Pieter Sipkema
- Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - John S. Yudkin
- Department of Internal Medicine, VU University Medical Center, Amsterdam, the Netherlands
- Department of Medicine, University College London, London, U.K
| | - Benoit Viollet
- INSERM, U1016, Cochin Institute, Paris, France
- Centre National de la Recherche Scientifique, UMR8104, Paris, France
- Paris Descartes University, Paris, France
| | - Erik A. Richter
- Department of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yvo M. Smulders
- Department of Internal Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | | | - Erik H. Serné
- Department of Internal Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Etto C. Eringa
- Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
- Corresponding author: Etto C. Eringa,
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Premilovac D, Bradley EA, Ng HL, Richards SM, Rattigan S, Keske MA. Muscle insulin resistance resulting from impaired microvascular insulin sensitivity in Sprague Dawley rats. Cardiovasc Res 2013; 98:28-36. [DOI: 10.1093/cvr/cvt015] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Reihmane D, Hansen AV, Gram M, Kuhlman AB, Nørregaard J, Pedersen HP, Lund MT, Helge JW, Dela F. Immobilization increases interleukin-6, but not tumour necrosis factor-α, release from the leg during exercise in humans. Exp Physiol 2012; 98:778-83. [PMID: 23143992 DOI: 10.1113/expphysiol.2012.069211] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Data on interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) release during acute exercise are not conclusive, and information is lacking about the impact of physical inactivity. Some studies have shown an increase, but others report no changes in IL-6 and TNF-α release during exercise. We have now studied the temporal relationship of leg IL-6 and TNF-α release before and during isolated two-legged exercise after 14 days of one-leg immobilization (IM) while the other leg served as the control (CON) leg. Fifteen healthy male subjects (mean ± SEM age, 23 ± 1 years; body mass index, 23.6 ± 0.7 kg m(-2); and maximal oxygen uptake, 46.8 ± 1.4 ml kg(-1) min(-1)) performed 45 min of two-legged dynamic knee-extensor exercise at 19.6 ± 0.8 W. Arterial and femoral venous blood samples from the CON and the IM leg were collected every 15 min during exercise, and leg blood flow was measured with Doppler ultrasound. The arterial plasma IL-6 concentration increased (P < 0.05) with exercise (rest, 1.3 ± 0.1 pg ml(-1); 15 min, 1.9 ± 0.2 pg ml(-1); 30 min, 2.4 ± 0.2 pg ml(-1); and 45 min, 3.1 ± 0.3 pg ml(-1)). Interleukin-6 release occurred after 15 min of exercise, and the release from the IM leg was significantly greater compared with the CON leg after 45 min (1114 ± 152 versus 606 ± 14 pg min(-1), respectively, P < 0.05). Tumour necrosis factor-α release did not differ between the CON and the IM leg, and arterial concentrations remained unchanged during exercise (P > 0.05). In conclusion, prior immobilization enhances release of IL-6 from the leg during exercise at a moderate workload, and the release is already present in the early phase of exercise. Neither immobilization nor exercise had an effect on TNF-α release in the working legs.
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Affiliation(s)
- Dace Reihmane
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
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St-Pierre P, Keith LJ, Richards SM, Rattigan S, Keske MA. Microvascular blood flow responses to muscle contraction are not altered by high-fat feeding in rats. Diabetes Obes Metab 2012; 14:753-61. [PMID: 22429614 DOI: 10.1111/j.1463-1326.2012.01598.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
AIM Exercise and insulin each increase microvascular blood flow and enhance glucose disposal in skeletal muscle. We have reported that insulin-mediated microvascular recruitment in a diet-induced model of insulin resistance (high-fat feeding for 4 weeks) is markedly impaired; however, the effect of muscle contraction in this model has not been previously explored. METHODS We fed rats either normal (ND, 10% calories from fat) or high-fat (HFD, 60% calories from fat) diets ad libitum for 4-8 weeks. Animals were then anaesthetized and one hindlimb electrically stimulated to contract at 0.05, 0.1 and 2 Hz (field stimulation, 30 V, 0.1 ms duration) in 15 min stepwise increments. Femoral artery blood flow (Transonic flow probe), muscle microvascular blood flow (hindleg metabolism of 1-methylxanthine and contrast-enhanced ultrasound) and muscle glucose disposal (uptake of radiolabelled 2-deoxy-d-glucose and hindleg glucose disappearance) were measured. RESULTS Both ND and HFD rats received the same voltage across the leg and consequently developed the same muscle tension. Femoral artery blood flow in the contracting leg increased during 2 Hz contraction, but not during the lower frequencies and these effects were similar between ND and HFD rats. Muscle microvascular blood flow significantly increased in a contraction frequency-dependent manner, and preceded increases in total limb blood flow and these effects were similar between ND and HFD rats. Muscle glucose disposal was markedly elevated during 2 Hz contraction and was comparable between ND and HFD rats. CONCLUSION Contraction-mediated muscle microvascular recruitment and glucose uptake are not impaired in the HFD insulin resistant rat.
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Affiliation(s)
- P St-Pierre
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Australia
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43
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De Boer MP, Meijer RI, Wijnstok NJ, Jonk AM, Houben AJ, Stehouwer CD, Smulders YM, Eringa EC, Serné EH. Microvascular dysfunction: a potential mechanism in the pathogenesis of obesity-associated insulin resistance and hypertension. Microcirculation 2012; 19:5-18. [PMID: 21883642 DOI: 10.1111/j.1549-8719.2011.00130.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The intertwined epidemics of obesity and related disorders such as hypertension, insulin resistance, type 2 diabetes, and subsequent cardiovascular disease pose a major public health challenge. To meet this challenge, we must understand the interplay between adipose tissue and the vasculature. Microvascular dysfunction is important not only in the development of obesity-related target-organ damage but also in the development of cardiovascular risk factors such as hypertension and insulin resistance. The present review examines the role of microvascular dysfunction as an explanation for the associations among obesity, hypertension, and impaired insulin-mediated glucose disposal. We also discuss communicative pathways from adipose tissue to the microcirculation.
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Affiliation(s)
- Michiel P De Boer
- Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
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Abstract
Insulin increases microvascular perfusion and substrate exchange surface area in muscle, which is pivotal for hormone action and substrate exchange, by activating insulin signaling cascade in the endothelial cells to produce nitric oxide. This action of insulin is closely coupled with its metabolic action and type 2 diabetes is associated with both metabolic and microvascular insulin resistance. Muscle microvascular perfusion/volume can be assessed by 1-methylxanthine metabolism, contrast-enhanced ultrasound and positron emission tomography. In addition to insulin, several factors have been shown to recruit muscle microvasculature, including exercise or muscle contraction, mixed meals, glucagon-like peptide 1 and angiotensin II type 1 receptor (AT(1)R) blocker. On the other hand, factors that cause metabolic insulin resistance, such as inflammatory cytokines, free fatty acids, and selective activation of the AT(1)R, are capable of causing microvascular insulin resistance. Therapies targeting microvascular insulin resistance may help prevent or control diabetes and decrease the associated cardiovascular morbidity and mortality.
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Affiliation(s)
- Zhenqi Liu
- Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Virginia Health System, Charlottesville, VA, USA
| | - Seung-Hyun Ko
- Division of Endocrinology & Metabolism, Department of Internal Medicine, The Catholic University of Korea College of Medicine, Suwon, Korea
| | - Weidong Chai
- Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Virginia Health System, Charlottesville, VA, USA
| | - Wenhong Cao
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Mulligan KX, Morris RT, Otero YF, Wasserman DH, McGuinness OP. Disassociation of muscle insulin signaling and insulin-stimulated glucose uptake during endotoxemia. PLoS One 2012; 7:e30160. [PMID: 22276152 PMCID: PMC3262801 DOI: 10.1371/journal.pone.0030160] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 12/14/2011] [Indexed: 01/04/2023] Open
Abstract
Lipopolysaccharide (LPS) elicits a strong immune response, which leads to the release of inflammatory cytokines. Increased cytokine production has been shown to impair insulin-mediated glucose disposal. LPS can alter other factors, such as muscle blood flow and insulin signaling in the myocyte,that can influence glucose disposal. We hypothesize that LPS induced impairments in cardiovascular function contribute to the associated impairments in insulin action in vivo. Male wild-type C57BL/6J mice had a catheter implanted in the jugular vein for infusions and the carotid artery for sampling 5 days prior to the hyperinsulinemic-euglycemic clamp. Mice were treated with vehicle, low-(1 ug/gBW) or high-dose (10 ug/gBW) LPS 4 hours prior to the clamp. Muscle glucose uptake (MGU) was assessed using [2-14C] deoxyglucose. While both low- and high-dose LPS inhibited insulin-stimulated MGU compared to vehicle-treated mice, the impairment was more significant with the high-dose treatment (∼25% in soleus and ∼70% in both gastrocnemius and vastus lateralis). Interestingly, insulin signaling through the PI3-kinase pathway in the muscle was not affected by this treatment suggesting that the decrease in MGU is not directly due to impairments in muscle insulin action. Echocardiography demonstrated that high-dose LPS treatment significantly decreased stroke volume (∼30%), heart rate (∼35%), and cardiac output (∼50%). These observations were not seen with vehicle or low-dose LPS treatment. High-dose LPS treatment also significantly decreased muscle blood flow (∼70%) and whole body oxygen consumption (∼50%). Thus, in vivo acute endotoxemia does not impair insulin signaling through the PI3-kinase pathway in skeletal muscle and decreased tissue blood flow likely plays a central role in the impairment of glucose uptake in the muscle.
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Affiliation(s)
- Kimberly X. Mulligan
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine Nashville, Tennessee, United States of America
| | - R. Tyler Morris
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine Nashville, Tennessee, United States of America
| | - Yolanda F. Otero
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine Nashville, Tennessee, United States of America
| | - David H. Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine Nashville, Tennessee, United States of America
| | - Owen P. McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine Nashville, Tennessee, United States of America
- * E-mail:
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Assoumou HGN, Barthelemy JC, Garet M, Dauphinot V, Celle S, Pichot V, Kossovsky M, Gaspoz JM, Roche F. Increased Waist Circumference Is the Component of Metabolic Syndrome the Most Strongly Associated with Elevated C-Reactive Protein in Elderly. Metab Syndr Relat Disord 2011; 9:281-5. [DOI: 10.1089/met.2010.0115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Hourfil-Gabin Ntougou Assoumou
- Clinical and Exercise Physiology Laboratory, University Hospital and Jean Monnet University, PRES University of Lyon, Saint-Etienne, France
| | - Jean Claude Barthelemy
- Clinical and Exercise Physiology Laboratory, University Hospital and Jean Monnet University, PRES University of Lyon, Saint-Etienne, France
| | - Martin Garet
- Clinical and Exercise Physiology Laboratory, University Hospital and Jean Monnet University, PRES University of Lyon, Saint-Etienne, France
| | - Virginie Dauphinot
- Neurology Unit D, Research Memory Centre, University Hospital of Lyon, Lyon, France
| | - Sébastien Celle
- Clinical and Exercise Physiology Laboratory, University Hospital and Jean Monnet University, PRES University of Lyon, Saint-Etienne, France
| | - Vincent Pichot
- Clinical and Exercise Physiology Laboratory, University Hospital and Jean Monnet University, PRES University of Lyon, Saint-Etienne, France
| | - Michel Kossovsky
- Department of Community Medicine and Primary Care, Geneva University Hospitals and Geneva University Medical School, Geneva, Switzerland
| | - Jean-Michel Gaspoz
- Department of Community Medicine and Primary Care, Geneva University Hospitals and Geneva University Medical School, Geneva, Switzerland
| | - Frédéric Roche
- Clinical and Exercise Physiology Laboratory, University Hospital and Jean Monnet University, PRES University of Lyon, Saint-Etienne, France
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Genders AJ, Bradley EA, Rattigan S, Richards SM. cGMP phosphodiesterase inhibition improves the vascular and metabolic actions of insulin in skeletal muscle. Am J Physiol Endocrinol Metab 2011; 301:E342-50. [PMID: 21653225 DOI: 10.1152/ajpendo.00691.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is considerable support for the concept that insulin-mediated increases in microvascular blood flow to muscle impact significantly on muscle glucose uptake. Since the microvascular blood flow increases with insulin have been shown to be nitric oxide-dependent inhibition of cGMP-degrading phosphodiesterases (cGMP PDEs) is predicted to enhance insulin-mediated increases in microvascular perfusion and muscle glucose uptake. Therefore, we studied the effects of the pan-cGMP PDE inhibitor zaprinast on the metabolic and vascular actions of insulin in muscle. Hyperinsulinemic euglycemic clamps (3 mU·min(-1)·kg(-1)) were performed in anesthetized rats and changes in microvascular blood flow assessed from rates of 1-methylxanthine metabolism across the muscle bed by capillary xanthine oxidase in response to insulin and zaprinast. We also characterized cGMP PDE isoform expression in muscle by real-time PCR and immunostaining of frozen muscle sections. Zaprinast enhanced insulin-mediated microvascular perfusion by 29% and muscle glucose uptake by 89%, while whole body glucose infusion rate during insulin infusion was increased by 33% at 2 h. PDE2, -9, and -10 were the major isoforms expressed at the mRNA level in muscle, while PDE1B, -9A, -10A, and -11A proteins were expressed in blood vessels. Acute administration of the cGMP PDE inhibitor zaprinast enhances muscle microvascular blood flow and glucose uptake response to insulin. The expression of a number of cGMP PDE isoforms in skeletal muscle suggests that targeting specific cGMP PDE isoforms may provide a promising avenue for development of a novel class of therapeutics for enhancing muscle insulin sensitivity.
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Affiliation(s)
- A J Genders
- Menzies Research Institute, University of Tasmania, Hobart 7001, Tasmania, Australia
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Ko SH, Cao W, Liu Z. Hypertension management and microvascular insulin resistance in diabetes. Curr Hypertens Rep 2011; 12:243-51. [PMID: 20582734 DOI: 10.1007/s11906-010-0114-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Type 2 diabetes is in essence a vascular disease and is frequently associated with hypertension, macrovascular events, and microvascular complications. Microvascular dysfunction, including impaired recruitment and capillary rarefaction, has been implicated in the pathogenesis of diabetic complications. Microvascular insulin resistance and renin-angiotensin system upregulation are present in diabetes, and each contributes to the development of hypertension and microvascular dysfunction. In the insulin-sensitive state, insulin increases microvascular perfusion by increasing endothelial nitric oxide production, but this effect is abolished by insulin resistance. Angiotensin II, acting via the type 1 receptors, induces inflammation and oxidative stress, leading to impaired insulin signaling, reduced nitric oxide availability, and vasoconstriction. Conversely, it acts on the type 2 receptors to cause vasodilatation. Because substrate and hormonal exchanges occur in the microvasculature, antihypertensive agents targeted to improve microvascular insulin sensitivity and function may have beneficial effects beyond their capacity to lower blood pressure in patients with diabetes.
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Affiliation(s)
- Seung-Hyun Ko
- Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Virginia Health System, PO Box 801410, Charlottesville, VA 22908-1410, USA
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Jonk AM, Houben AJ, Schaper NC, de Leeuw PW, Serné EH, Smulders YM, Stehouwer CD. Meal-related increases in microvascular vasomotion are impaired in obese individuals: a potential mechanism in the pathogenesis of obesity-related insulin resistance. Diabetes Care 2011; 34 Suppl 2:S342-8. [PMID: 21525480 PMCID: PMC3632204 DOI: 10.2337/dc11-s240] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Amy M Jonk
- Department of Internal Medicine, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands
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Wang N, Ko SH, Chai W, Li G, Barrett EJ, Tao L, Cao W, Liu Z. Resveratrol recruits rat muscle microvasculature via a nitric oxide-dependent mechanism that is blocked by TNFα. Am J Physiol Endocrinol Metab 2011; 300:E195-201. [PMID: 20978231 PMCID: PMC3023212 DOI: 10.1152/ajpendo.00414.2010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Resveratrol, a polyphenol found in many plants, has antioxidant and anti-inflammatory actions. It also improves endothelial function and may be cardioprotective. Tumor necrosis factor-α (TNFα) causes oxidative stress and microvascular endothelial dysfunction. Whether resveratrol affects microvascular function in vivo and, if so, whether inflammatory cytokines antagonize its microvascular action are not clear. In cultured bovine aortic endothelial cells (BAECs), resveratrol (100 nM) increased the phosphorylation of protein kinase B (Akt), endothelial nitric oxide (NO) synthase (eNOS), and ERK1/2 within 15 min by more than twofold, and this effect lasted for at least 2 h. Treatment of BAECs with TNFα (10 ng/ml) significantly increased the NADPH oxidase activity and the production of hydrogen peroxide and superoxide. Pretreatment of cells with resveratrol (100 nM) prevented each of these. Injection (ip) of resveratrol in rats potently increased muscle microvascular blood volume (MBV; P = 0.007) and flow (MBF; P < 0.02) within 30 min, and this was sustained for at least 2 h. The phosphorylation of Akt in liver or muscle was unchanged. Superimposed systemic infusion of L-NAME (NOS inhibitor) completely abolished resveratrol-induced increases in MBV and MBF. Similarly, systemic infusion of TNFα prevented resveratrol-induced muscle microvascular recruitment. In conclusion, resveratrol activates eNOS and increases muscle microvascular recruitment via an NO-dependent mechanism. Despite the potent antioxidant effect of resveratrol, TNFα at concentrations that block insulin-mediated muscle microvascular recruitment completely neutralized resveratrol's microvascular action. Thus, chronic inflammation, as seen in type 2 diabetes, may limit resveratrol's vasodilatory actions on muscle microvasculature.
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Affiliation(s)
- Nasui Wang
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908, USA
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