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Potential of Beetroot and Blackcurrant Compounds to Improve Metabolic Syndrome Risk Factors. Metabolites 2021; 11:metabo11060338. [PMID: 34070362 PMCID: PMC8228969 DOI: 10.3390/metabo11060338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/20/2021] [Accepted: 05/20/2021] [Indexed: 12/15/2022] Open
Abstract
Metabolic syndrome (MetS) is a group of metabolic abnormalities, which together lead to increased risk of coronary heart disease (CHD) and type 2 diabetes mellitus (T2DM), as well as reduced quality of life. Dietary nitrate, betalains and anthocyanins may improve risk factors for MetS and reduce the risk of development of CHD and T2DM. Beetroot is a rich source of dietary nitrate, and anthocyanins are present in high concentrations in blackcurrants. This narrative review considers the efficacy of beetroot and blackcurrant compounds as potential agents to improve MetS risk factors, which could lead to decreased risk of CHD and T2DM. Further research is needed to establish the mechanisms through which these outcomes may occur, and chronic supplementation studies in humans may corroborate promising findings from animal models and acute human trials.
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Stokes SM, Bertin FR, Stefanovski D, Belknap JK, Medina-Torres CE, Pollitt CC, van Eps AW. Lamellar energy metabolism and perfusion in the euglycaemic hyperinsulinaemic clamp model of equine laminitis. Equine Vet J 2020; 52:577-584. [PMID: 31845378 DOI: 10.1111/evj.13224] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/29/2019] [Accepted: 12/04/2019] [Indexed: 01/19/2023]
Abstract
BACKGROUND Hyperinsulinaemia is associated with the development of endocrinopathic laminitis; however, the mechanisms remain unclear. OBJECTIVES Evaluate the effects of hyperinsulinaemia on lamellar energy metabolism and perfusion during laminitis development. STUDY DESIGN In vivo experiment. METHODS Eight Standardbred horses were instrumented with a microdialysis probe in the lamellae of a forelimb. A 24 hours baseline period (BASELINE) was followed by 48 hours of a continuous euglycaemic hyperinsulinaemic clamp (EHC) from 24 to 72 hours (CLAMP). Microdialysate was collected every 6 hours and analysed for glucose, lactate and pyruvate concentrations and lactate-to-pyruvate ratio (L:P). Microdialysis urea clearance was used to estimate lamellar tissue perfusion. Archived microdialysis samples from six identically instrumented Standardbred horses served as controls (CON). Variables were compared over time and between EHC and CON horses using a mixed-effects linear regression model. RESULTS Glucose concentration decreased during the CLAMP period in CON and EHC horses (P < .001), but there was no difference between CON and EHC (P > .9). Lactate concentration increased during the CLAMP period in CON and EHC horses (P < .001), however, the rate of increase was significantly higher in EHC horses relative to CON (P = .014). There was a relative increase in pyruvate concentration in EHC horses compared with CON during the CLAMP period (P = .03). L:P increased significantly in CON horses during the CLAMP period (P < .001) but not in EHC (P = .1). Urea clearance did not change in CON (P = .9) or EHC (P = .05) during the CLAMP, but did increase in EHC relative to CON (P = .02). MAIN LIMITATIONS The effects of microdialysis probe implantation on perfusion and metabolism remain unclear. The EHC model may not mimic natural endocrinopathic laminitis. CONCLUSIONS Laminitis developed without evidence of lamellar hypoperfusion or energy stress. Therapies to improve perfusion are unlikely to affect the initial development of endocrinopathic laminitis.
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Affiliation(s)
- Simon M Stokes
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia
| | - Francois R Bertin
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia
| | - Darko Stefanovski
- New Bolton Center, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania
| | - James K Belknap
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Carlos E Medina-Torres
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia
| | - Christopher C Pollitt
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia
| | - Andrew W van Eps
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia.,New Bolton Center, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania
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Ale-Agha N, Goy C, Jakobs P, Spyridopoulos I, Gonnissen S, Dyballa-Rukes N, Aufenvenne K, von Ameln F, Zurek M, Spannbrucker T, Eckermann O, Jakob S, Gorressen S, Abrams M, Grandoch M, Fischer JW, Köhrer K, Deenen R, Unfried K, Altschmied J, Haendeler J. CDKN1B/p27 is localized in mitochondria and improves respiration-dependent processes in the cardiovascular system-New mode of action for caffeine. PLoS Biol 2018; 16:e2004408. [PMID: 29927970 PMCID: PMC6013014 DOI: 10.1371/journal.pbio.2004408] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 05/18/2018] [Indexed: 12/16/2022] Open
Abstract
We show that the cyclin-dependent kinase inhibitor 1B (CDKN1B)/p27, previously known as a cell cycle inhibitor, is also localized within mitochondria. The migratory capacity of endothelial cells, which need intact mitochondria, is completely dependent on mitochondrial p27. Mitochondrial p27 improves mitochondrial membrane potential, increases adenosine triphosphate (ATP) content, and is required for the promigratory effect of caffeine. Domain mapping of p27 revealed that the N-terminus and C-terminus are required for those improvements. Further analysis of those regions revealed that the translocation of p27 into the mitochondria and its promigratory activity depend on serine 10 and threonine 187. In addition, mitochondrial p27 protects cardiomyocytes against apoptosis. Moreover, mitochondrial p27 is necessary and sufficient for cardiac myofibroblast differentiation. In addition, p27 deficiency and aging decrease respiration in heart mitochondria. Caffeine does not increase respiration in p27-deficient animals, whereas aged mice display improvement after 10 days of caffeine in drinking water. Moreover, caffeine induces transcriptome changes in a p27-dependent manner, affecting mostly genes relevant for mitochondrial processes. Caffeine also reduces infarct size after myocardial infarction in prediabetic mice and increases mitochondrial p27. Our data characterize mitochondrial p27 as a common denominator that improves mitochondria-dependent processes and define an increase in mitochondrial p27 as a new mode of action of caffeine.
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Affiliation(s)
- Niloofar Ale-Agha
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Christine Goy
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Philipp Jakobs
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Ioakim Spyridopoulos
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Stefanie Gonnissen
- Core Unit Biosafety Level 2 Laboratory, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Nadine Dyballa-Rukes
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Karin Aufenvenne
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Florian von Ameln
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
- Core Unit Biosafety Level 2 Laboratory, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Mark Zurek
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Tim Spannbrucker
- Environmentally-induced Skin and Lung Aging, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Olaf Eckermann
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Sascha Jakob
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Simone Gorressen
- Institute for Pharmacology and Clinical Pharmacology, Medical Faculty, HHU Duesseldorf, Duesseldorf, Germany
| | - Marcel Abrams
- Institute for Pharmacology and Clinical Pharmacology, Medical Faculty, HHU Duesseldorf, Duesseldorf, Germany
| | - Maria Grandoch
- Institute for Pharmacology and Clinical Pharmacology, Medical Faculty, HHU Duesseldorf, Duesseldorf, Germany
| | - Jens W. Fischer
- Institute for Pharmacology and Clinical Pharmacology, Medical Faculty, HHU Duesseldorf, Duesseldorf, Germany
| | - Karl Köhrer
- Biological and Medical Research Center (BMFZ), HHU, Duesseldorf, Germany
| | - René Deenen
- Biological and Medical Research Center (BMFZ), HHU, Duesseldorf, Germany
| | - Klaus Unfried
- Environmentally-induced Skin and Lung Aging, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Joachim Altschmied
- Core Unit Biosafety Level 2 Laboratory, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Judith Haendeler
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
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Efficacy of Endovascular Radiofrequency Ablation for Thromboangiitis Obliterans (Buerger's Disease). Ann Vasc Surg 2017; 42:78-83. [DOI: 10.1016/j.avsg.2016.11.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 10/31/2016] [Accepted: 11/09/2016] [Indexed: 01/04/2023]
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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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Bedinger DH, Adams SH. Metabolic, anabolic, and mitogenic insulin responses: A tissue-specific perspective for insulin receptor activators. Mol Cell Endocrinol 2015; 415:143-56. [PMID: 26277398 DOI: 10.1016/j.mce.2015.08.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/05/2015] [Accepted: 08/09/2015] [Indexed: 12/17/2022]
Abstract
Insulin acts as the major regulator of the fasting-to-fed metabolic transition by altering substrate metabolism, promoting energy storage, and helping activate protein synthesis. In addition to its glucoregulatory and other metabolic properties, insulin can also act as a growth factor. The metabolic and mitogenic responses to insulin are regulated by divergent post-receptor signaling mechanisms downstream from the activated insulin receptor (IR). However, the anabolic and growth-promoting properties of insulin require tissue-specific inter-relationships between the two pathways, and the nature and scope of insulin-regulated processes vary greatly across tissues. Understanding the nuances of this interplay between metabolic and growth-regulating properties of insulin would have important implications for development of novel insulin and IR modulator therapies that stimulate insulin receptor activation in both pathway- and tissue-specific manners. This review will provide a unique perspective focusing on the roles of "metabolic" and "mitogenic" actions of insulin signaling in various tissues, and how these networks should be considered when evaluating selective pharmacologic approaches to prevent or treat metabolic disease.
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Affiliation(s)
| | - Sean H Adams
- Arkansas Children's Nutrition Center and University of Arkansas for Medical Sciences, Department of Pediatrics, Little Rock, AR, USA
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Hussain M, Janghorbani M, Schuette S, Considine RV, Chisholm RL, Mather KJ. Failure of hyperglycemia and hyperinsulinemia to compensate for impaired metabolic response to an oral glucose load. J Diabetes Complications 2015; 29:238-44. [PMID: 25511878 PMCID: PMC4333082 DOI: 10.1016/j.jdiacomp.2014.11.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 11/05/2014] [Accepted: 11/17/2014] [Indexed: 01/23/2023]
Abstract
OBJECTIVE To evaluate whether the augmented insulin and glucose response to a glucose challenge is sufficient to compensate for defects in glucose utilization in obesity and type 2 diabetes, using a breath test measurement of integrated glucose metabolism. METHODS Non-obese, obese normoglycemic and obese type 2 diabetic subjects were studied on 2 consecutive days. A 75g oral glucose load spiked with ¹³C-glucose was administered, measuring exhaled breath ¹³CO₂ as an integrated measure of glucose metabolism and oxidation. A hyperinsulinemic euglycemic clamp was performed, measuring whole body glucose disposal rate. Body composition was measured by DEXA. Multivariable analyses were performed to evaluate the determinants of the breath ¹³CO₂. RESULTS Breath ¹³CO₂ was reduced in obese and type 2 diabetic subjects despite hyperglycemia and hyperinsulinemia. The primary determinants of breath response were lean mass, fat mass, fasting FFA concentrations, and OGTT glucose excursion. Multiple approaches to analysis showed that hyperglycemia and hyperinsulinemia were not sufficient to compensate for the defect in glucose metabolism in obesity and diabetes. CONCLUSIONS Augmented insulin and glucose responses during an OGTT are not sufficient to overcome the underlying defects in glucose metabolism in obesity and diabetes.
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Affiliation(s)
- M Hussain
- Indiana University School of Medicine, Indianapolis, IN
| | - M Janghorbani
- BioChemAnalysis Inc., Chicago IL; Center for Stable Isotope Research Inc, Chicago IL
| | | | - R V Considine
- Indiana University School of Medicine, Indianapolis, IN
| | - R L Chisholm
- Indiana University School of Medicine, Indianapolis, IN
| | - K J Mather
- Indiana University School of Medicine, Indianapolis, IN.
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Rajendran P, Rengarajan T, Thangavel J, Nishigaki Y, Sakthisekaran D, Sethi G, Nishigaki I. The vascular endothelium and human diseases. Int J Biol Sci 2013; 9:1057-69. [PMID: 24250251 PMCID: PMC3831119 DOI: 10.7150/ijbs.7502] [Citation(s) in RCA: 916] [Impact Index Per Article: 83.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/07/2013] [Indexed: 02/07/2023] Open
Abstract
Alterations of endothelial cells and the vasculature play a central role in the pathogenesis of a broad spectrum of the most dreadful of human diseases, as endothelial cells have the key function of participating in the maintenance of patent and functional capillaries. The endothelium is directly involved in peripheral vascular disease, stroke, heart disease, diabetes, insulin resistance, chronic kidney failure, tumor growth, metastasis, venous thrombosis, and severe viral infectious diseases. Dysfunction of the vascular endothelium is thus a hallmark of human diseases. In this review the main endothelial abnormalities found in various human diseases such as cancer, diabetes mellitus, atherosclerosis, and viral infections are addressed.
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Affiliation(s)
- Peramaiyan Rajendran
- 1. NPO-International Laboratory of Biochemistry,1-166, Uchide, Nakagawa-ku, Nagoya 454-0926, Japan
| | | | - Jayakumar Thangavel
- 2. Department of Pharmacology and Center of Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Yutaka Nishigaki
- 1. NPO-International Laboratory of Biochemistry,1-166, Uchide, Nakagawa-ku, Nagoya 454-0926, Japan
| | - Dhanapal Sakthisekaran
- 3. Department of Medical Biochemistry, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India 600 113
| | - Gautam Sethi
- 4. Department of Pharmacology,Yong Loo Lin School of Medicine,National University Health System, 10 Medical Drive, MD11, #05-09, Clinical Research Centre, Singapore 117597
| | - Ikuo Nishigaki
- 1. NPO-International Laboratory of Biochemistry,1-166, Uchide, Nakagawa-ku, Nagoya 454-0926, Japan
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Bourgoin F, Bachelard H, Badeau M, Larivière R, Nadeau A, Pitre M. Effects of tempol on endothelial and vascular dysfunctions and insulin resistance induced by a high-fat high-sucrose diet in the rat. Can J Physiol Pharmacol 2013; 91:547-61. [DOI: 10.1139/cjpp-2012-0273] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the effects of treatment with tempol (an antioxidant) on vascular and metabolic dysfunction induced by a high-fat high-sucrose (HFHS) diet. Rats were randomized to receive an HFHS or chow diet with or without tempol treatment (1.5 mmol·(kg body mass)−1·day−1) for 4 weeks. Blood pressure, heart rate, and blood flow were measured in the rats by using intravascular catheters and Doppler flow probes. Insulin sensitivity and vascular responses to insulin were assessed during a euglycemic–hyperinsulinemic clamp. In-vitro studies were performed to evaluate vascular reactivity and endothelial and inducible nitric oxide synthase (eNOS; iNOS) expression in vascular and muscle tissues. Endothelin, nitrotyrosine, and NAD(P)H oxidase expressions were determined in vascular tissues, and glucose transport activity and glucose transporter 4 (GLUT4) expression were examined in muscles. Tempol treatment was found to prevent alterations in insulin sensitivity, glucose transport activity, GLUT4 expression, and vascular reactivity, and to prevent increases in plasma insulin, blood pressure, and heart rate noted in the untreated HFHS-fed rats. These were associated with increased levels of eNOS expression in vascular and muscle tissues, but reductions in nitrotyrosine, endothelin, NAD(P)H oxidase, and iNOS expressions. Therefore, oxidative stress induced by a relatively short-term HFHS diet could contribute to the early development of vascular and metabolic abnormalities in rats.
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Affiliation(s)
- Frédéric Bourgoin
- Endocrinology and Nephrology Axis, CHUQ Research Center from the CHUL, Department of Medicine, Laval University, 2705 Laurier boulevard, Québec, QC G1V 4G2, Canada
| | - Hélène Bachelard
- Endocrinology and Nephrology Axis, CHUQ Research Center from the CHUL, Department of Medicine, Laval University, 2705 Laurier boulevard, Québec, QC G1V 4G2, Canada
| | - Mylène Badeau
- Endocrinology and Nephrology Axis, CHUQ Research Center from the CHUL, Department of Medicine, Laval University, 2705 Laurier boulevard, Québec, QC G1V 4G2, Canada
| | - Richard Larivière
- Division of Nephrology and Hypertension, CHUQ Research Center from the Hôtel-Dieu de Québec, Department of Medicine, Faculty of Medicine, Laval University, Québec, Canada
| | - André Nadeau
- Endocrinology and Nephrology Axis, CHUQ Research Center from the CHUL, Department of Medicine, Laval University, 2705 Laurier boulevard, Québec, QC G1V 4G2, Canada
| | - Maryse Pitre
- Endocrinology and Nephrology Axis, CHUQ Research Center from the CHUL, Department of Medicine, Laval University, 2705 Laurier boulevard, Québec, QC G1V 4G2, Canada
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Tabit CE, Chung WB, Hamburg NM, Vita JA. Endothelial dysfunction in diabetes mellitus: molecular mechanisms and clinical implications. Rev Endocr Metab Disord 2010; 11:61-74. [PMID: 20186491 PMCID: PMC2882637 DOI: 10.1007/s11154-010-9134-4] [Citation(s) in RCA: 386] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cardiovascular disease is a major complication of diabetes mellitus, and improved strategies for prevention and treatment are needed. Endothelial dysfunction contributes to the pathogenesis and clinical expression of atherosclerosis in diabetes mellitus. This article reviews the evidence linking endothelial dysfunction to human diabetes mellitus and experimental studies that investigated the responsible mechanisms. We then discuss the implications of these studies for current management and for new approaches for the prevention and treatment of cardiovascular disease in patients with diabetes mellitus.
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Affiliation(s)
- Corey E. Tabit
- Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - William B. Chung
- Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Naomi M. Hamburg
- Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Joseph A. Vita
- Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
- Section of Cardiology, Boston Medical Center, 88 East Newton Street, Boston, MA 02118, USA,
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Versari D, Daghini E, Virdis A, Ghiadoni L, Taddei S. Endothelial dysfunction as a target for prevention of cardiovascular disease. Diabetes Care 2009; 32 Suppl 2:S314-21. [PMID: 19875572 PMCID: PMC2811443 DOI: 10.2337/dc09-s330] [Citation(s) in RCA: 359] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Daniele Versari
- Department of Internal Medicine, University of Pisa, Pisa, Italy
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Abstract
Insulin is a vascular hormone, able to influence vascular cell responses. In this review, we consider the insulin actions on vascular endothelium and on vascular smooth muscle cells (VSMC) both in physiological conditions and in the presence of insulin resistance. In particular, we focus the relationships between activation of insulin signalling pathways of phosphatidylinositol-3 kinase (PI3-K) and mitogen-activated protein kinase (MAPK) and the different vascular actions of insulin, with a particular attention to the insulin ability to activate the pathway nitric oxide (NO)/cyclic GMP/PKG via PI3-K, owing to the peculiar relevance of NO in vascular biology. We also discuss the insulin actions mediated by the MAPK pathway (such as endothelin-1 synthesis and secretion and VSMC proliferation and migration) and by the interactions between the two pathways, both in insulin-sensitive and in insulin-resistant states. Finally, we consider the influence of free fatty acids, cytokines and endothelin on vascular insulin resistance.
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Affiliation(s)
- Giovanni Anfossi
- Internal Medicine University Unit, San Luigi Gonzaga Faculty of Medicine and Department of Clinical and Biological Sciences, Turin University, San Luigi Gonzaga Hospital, 10043 Orbassano, Turin, Italy
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Clough GF, Turzyniecka M, Walter L, Krentz AJ, Wild SH, Chipperfield AJ, Gamble J, Byrne CD. Muscle microvascular dysfunction in central obesity is related to muscle insulin insensitivity but is not reversed by high-dose statin treatment. Diabetes 2009; 58:1185-91. [PMID: 19208914 PMCID: PMC2671046 DOI: 10.2337/db08-1688] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To test the hypotheses that decreased insulin-mediated glucose disposal in muscle is associated with a reduced muscle microvascular exchange capacity (Kf) and that 6 months of high-dose statin therapy would improve microvascular function in people with central obesity. RESEARCH DESIGN AND METHODS We assessed skeletal muscle microvascular function, visceral fat mass, physical activity levels, fitness, and insulin sensitivity in skeletal muscle in 22 female and 17 male volunteers with central obesity whose age (mean +/- SD) was 51 +/- 9 years. We tested the effect of atorvastatin (40 mg daily) on muscle microvascular function in a randomized, double-blind, placebo-controlled trial lasting 6 months. RESULTS Kf was negatively associated with a measure of glycemia (A1C; r = -0.44, P = 0.006) and positively associated with insulin sensitivity (the ratio of insulin-stimulated glucose effectiveness, or M value, to the mean insulin concentration, or I value; r = 0.39, P = 0.02). In regression modeling, A1C, visceral fat mass, and M:I explained 38% of the variance in Kf (in a linear regression model with Kf as the outcome [R2 = 0.38, P = 0.005]). M:I was associated with Kf independently of visceral fat mass (B coefficient 3.13 [95% CI 0.22-6.02], P = 0.036). Although 6 months' treatment with atorvastatin decreased LDL cholesterol by 51% (P < 0.001) and plasma high-sensitivity C-reactive protein by 75% (P = 0.02), microvascular function was unchanged. CONCLUSIONS Decreased insulin-mediated glucose uptake in skeletal muscle is associated with impaired muscle microvascular exchange capacity (Kf), independently of visceral fat mass. Muscle microvascular function is not improved by 6 months of high-dose statin treatment, despite marked statin-mediated improvements in lipid metabolism and decreased inflammation.
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Affiliation(s)
| | | | - Lara Walter
- School of Medicine, University of Southampton, Southampton, U.K.; the
| | - Andrew J. Krentz
- School of Medicine, University of Southampton, Southampton, U.K.; the
| | - Sarah H. Wild
- Public Health Sciences, University of Edinburgh, Edinburgh, U.K.; the
| | | | | | - Christopher D. Byrne
- School of Medicine, University of Southampton, Southampton, U.K.; the
- Corresponding author: Christopher D. Byrne,
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Lteif AA, Fulford AD, Considine RV, Gelfand I, Baron AD, Mather KJ. Hyperinsulinemia fails to augment ET-1 action in the skeletal muscle vascular bed in vivo in humans. Am J Physiol Endocrinol Metab 2008; 295:E1510-7. [PMID: 18957616 PMCID: PMC2603554 DOI: 10.1152/ajpendo.90549.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Endogenous endothelin action is augmented in human obesity and type 2 diabetes and contributes to endothelial dysfunction and impairs insulin-mediated vasodilation in humans. We hypothesized that insulin resistance-associated hyperinsulinemia could preferentially drive endothelin-mediated vasoconstriction. We applied hyperinsulinemic-euglycemic clamps with higher insulin dosing in obese subjects than lean subjects (30 vs. 10 mU.m(-2).min(-1), respectively), with the goal of matching insulin's nitric oxide (NO)-mediated vascular effects. We predicted that, under these circumstances, insulin-stimulated endothelin-1 (ET-1) action (assessed with the type A endothelin receptor antagonist BQ-123) would be augmented in proportion to hyperinsulinemia. NO bioactivity was assessed using the nitric oxide synthase inhibitor N(G)-monomethyl-l-arginine. Insulin-mediated vasodilation and insulin-stimulated NO bioavailability were well matched across groups by this approach. As expected, steady-state insulin levels were approximately threefold higher in obese than lean subjects (109.2 +/- 10.2 pmol/l vs. 518.4 +/- 84.0, P = 0.03). Despite this, the augmentation of insulin-mediated vasodilation by BQ-123 was not different between groups. ET-1 flux across the leg was not augmented by insulin alone but was increased with the addition of BQ-123 to insulin (P = 0.01 BQ-123 effect, P = not significant comparing groups). Endothelin antagonism augmented insulin-stimulated NO bioavailability and NOx flux, but not differently between groups and not proportional to hyperinsulinemia. These findings do not support the hypothesis that insulin resistance-associated hyperinsulinemia preferentially drives endothelin-mediated vasoconstriction.
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Affiliation(s)
- Amale A Lteif
- Indiana Univ. School of Medicine, Indianapolis, IN 46202, USA
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17
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SIVAKUMAR P, SOARES M. Postprandial hypotension in older Australians: Relationship to glycaemia and habitual food intake. Nutr Diet 2007. [DOI: 10.1111/j.1747-0080.2007.00131.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Albertini JP, McMorn SO, Chen H, Mather RA, Valensi P. Effect of rosiglitazone on factors related to endothelial dysfunction in patients with type 2 diabetes mellitus. Atherosclerosis 2007; 195:e159-66. [PMID: 17280678 DOI: 10.1016/j.atherosclerosis.2007.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Revised: 12/19/2006] [Accepted: 01/02/2007] [Indexed: 11/23/2022]
Abstract
The effect of the insulin sensitizer rosiglitazone (RSG) on biological markers of endothelial dysfunction in subjects with type 2 diabetes mellitus (T2DM) was investigated in a 12-week, multi-center, randomized, double-blind study. One hundred and thirty-six subjects aged 40-70 years, with FPG > or = 7.0 and < or = 15.0 mmol/l, previously treated with a single oral anti-diabetic agent or diet/exercise, were randomized to RSG 8 mg/day (n=65) or placebo (PBO, n=71). Results revealed that RSG significantly reduced soluble (s)E-selectin by -10.9% (P=0.004) compared with PBO, but did not significantly alter soluble vascular cell adhesion molecule-1 (+0.6%, P=NS). Compared with PBO, RSG also significantly reduced plasminogen activator inhibitor-1 (-36.9%, P<0.001), tissue plasminogen activator antigen (-22.7%, P<0.001), FPG (-2.8 mmol/l, P<0.001), fasting fructosamine (-42.0 mg/dl, P<0.001). Post-prandial AUC(0-4h) for free fatty acids (FFAs) reduced by -6.5 mg/dl*h from baseline (P=0.03), a change that positively and significantly correlated with changes in sE-selectin (r=0.22, P=0.05). The incidence of adverse events was similar in the two groups (RSG: 35.4%; PBO: 40.8%); the majority mild or moderate. These data support the hypothesis that, in patients with T2DM, rosiglitazone has beneficial effects on biological markers of endothelial dysfunction. Improvements in insulin sensitivity and decreases in FFAs may play a role in these effects.
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Abstract
Insulin has important vascular actions to stimulate production of nitric oxide from endothelium. This leads to capillary recruitment, vasodilation, increased blood flow, and subsequent augmentation of glucose disposal in classical insulin target tissues (e.g., skeletal muscle). Phosphatidylinositol 3-kinase-dependent insulin-signaling pathways regulating endothelial production of nitric oxide share striking parallels with metabolic insulin-signaling pathways. Distinct MAPK-dependent insulin-signaling pathways (largely unrelated to metabolic actions of insulin) regulate secretion of the vasoconstrictor endothelin-1 from endothelium. These and other cardiovascular actions of insulin contribute to coupling metabolic and hemodynamic homeostasis under healthy conditions. Cardiovascular diseases are the leading cause of morbidity and mortality in insulin-resistant individuals. Insulin resistance is typically defined as decreased sensitivity and/or responsiveness to metabolic actions of insulin. This cardinal feature of diabetes, obesity, and dyslipidemia is also a prominent component of hypertension, coronary heart disease, and atherosclerosis that are all characterized by endothelial dysfunction. Conversely, endothelial dysfunction is often present in metabolic diseases. Insulin resistance is characterized by pathway-specific impairment in phosphatidylinositol 3-kinase-dependent signaling that in vascular endothelium contributes to a reciprocal relationship between insulin resistance and endothelial dysfunction. The clinical relevance of this coupling is highlighted by the findings that specific therapeutic interventions targeting insulin resistance often also ameliorate endothelial dysfunction (and vice versa). In this review, we discuss molecular mechanisms underlying cardiovascular actions of insulin, the reciprocal relationships between insulin resistance and endothelial dysfunction, and implications for developing beneficial therapeutic strategies that simultaneously target metabolic and cardiovascular diseases.
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Affiliation(s)
- Ranganath Muniyappa
- Diabetes Unit, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, Maryland 20892-1632, USA
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20
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Curran JN, Winter DC, Bouchier-Hayes D. Biological fate and clinical implications of arginine metabolism in tissue healing. Wound Repair Regen 2007; 14:376-86. [PMID: 16939563 DOI: 10.1111/j.1743-6109.2006.00151.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Since its discovery in 1987, many biological roles (including wound healing) have been identified for nitric oxide (NO). The gas is produced by NO synthase using the dibasic amino acid L-arginine as a substrate. It has been established that a lack of dietary L-arginine delays experimental wound healing. Arginine can also be metabolized to urea and ornithine by arginase-1, a pathway that generates L-proline, a substrate for collagen synthesis, and polyamines, which stimulate cellular proliferation. Herein, we review subjects of interest in arginine metabolism, with emphasis on the biochemistry of wound NO production, relative NO synthase isoform activity in healing wounds, cellular contributions to NO production, and NO effects and mechanisms of action in wound healing.
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Affiliation(s)
- John N Curran
- Department of Surgery, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland.
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21
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Affiliation(s)
- Deborah J Collinson
- Centre for Integrated Systems Biology & Medicine, School of Medical & Surgical Sciences, University of Nottingham, Nottingham, UK
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22
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Kim JA, Montagnani M, Koh KK, Quon MJ. Reciprocal relationships between insulin resistance and endothelial dysfunction: molecular and pathophysiological mechanisms. Circulation 2006; 113:1888-904. [PMID: 16618833 DOI: 10.1161/circulationaha.105.563213] [Citation(s) in RCA: 1121] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Endothelial dysfunction contributes to cardiovascular diseases, including hypertension, atherosclerosis, and coronary artery disease, which are also characterized by insulin resistance. Insulin resistance is a hallmark of metabolic disorders, including type 2 diabetes mellitus and obesity, which are also characterized by endothelial dysfunction. Metabolic actions of insulin to promote glucose disposal are augmented by vascular actions of insulin in endothelium to stimulate production of the vasodilator nitric oxide (NO). Indeed, NO-dependent increases in blood flow to skeletal muscle account for 25% to 40% of the increase in glucose uptake in response to insulin stimulation. Phosphatidylinositol 3-kinase-dependent insulin-signaling pathways in endothelium related to production of NO share striking similarities with metabolic pathways in skeletal muscle that promote glucose uptake. Other distinct nonmetabolic branches of insulin-signaling pathways regulate secretion of the vasoconstrictor endothelin-1 in endothelium. Metabolic insulin resistance is characterized by pathway-specific impairment in phosphatidylinositol 3-kinase-dependent signaling, which in endothelium may cause imbalance between production of NO and secretion of endothelin-1, leading to decreased blood flow, which worsens insulin resistance. Therapeutic interventions in animal models and human studies have demonstrated that improving endothelial function ameliorates insulin resistance, whereas improving insulin sensitivity ameliorates endothelial dysfunction. Taken together, cellular, physiological, clinical, and epidemiological studies strongly support a reciprocal relationship between endothelial dysfunction and insulin resistance that helps to link cardiovascular and metabolic diseases. In the present review, we discuss pathophysiological mechanisms, including inflammatory processes, that couple endothelial dysfunction with insulin resistance and emphasize important therapeutic implications.
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Affiliation(s)
- Jeong-a Kim
- Diabetes Unit, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, MD 20892-1632, USA
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23
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Wheatcroft SB, Shah AM, Li JM, Duncan E, Noronha BT, Crossey PA, Kearney MT. Preserved glucoregulation but attenuation of the vascular actions of insulin in mice heterozygous for knockout of the insulin receptor. Diabetes 2004; 53:2645-52. [PMID: 15448096 DOI: 10.2337/diabetes.53.10.2645] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Type 2 diabetes is preceded by years of insulin resistance and is characterized by reduced bioavailability of the antiatherosclerotic signaling molecule nitric oxide (NO) and premature atherosclerosis. The relationship between resistance to the glucoregulatory actions of insulin and its effects on the vasculature (in particular NO-dependent responses) is poorly characterized. We studied this relationship in mice heterozygous for knockout of the insulin receptor (IRKO), which have a mild perturbation of insulin signaling. Male heterozygous IRKO mice aged 8-12 weeks were compared with age- and sex-matched littermates. IRKO mice had fasting blood glucose, insulin, free fatty acid, and triglyceride levels similar to those of wild-type mice. Intraperitoneal glucose and insulin tolerance tests were also similar in the two groups. Insulin levels in response to a glucose load were approximately twofold higher in IRKO compared with wild-type mice (1.08 +/- 0.11 vs. 0.62 +/- 0.13 ng/ml; P = 0.004). Despite this mild metabolic phenotype, IRKO mice had increased systolic blood pressure (124 +/- 4 vs. 110 +/- 3 mmHg; P = 0.01). Basal NO bioactivity, assessed from the increase in tension of phenylephrine preconstricted aortic rings in response to the NO synthase inhibitor N(G)-monomethyl-l-arginine, was reduced in IRKO (61 +/- 14 vs. 152 +/- 30%; P = 0.005). Insulin-mediated NO release in aorta, assessed as the reduction in phenylephrine constrictor response after insulin preincubation, was lost in IRKO mice (5 +/- 8% change vs. 66 +/- 9% reduction in wild-type; P = 0.03). Insulin-stimulated aortic endothelial NO synthase phosphorylation was also significantly blunted in IRKO mice (P < 0.05). These data demonstrate that insulin-stimulated NO responses in the vasculature are exquisitely sensitive to changes in insulin-signaling pathways in contrast to the glucoregulatory actions of insulin. These findings underscore the importance of early intervention in insulin-resistant states, where glucose homeostasis may be normal but substantial abnormalities of the vascular effects of insulin may already be present.
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Affiliation(s)
- Stephen B Wheatcroft
- Department of Cardiology, Guy's King's & St. Thomas' School of Medicine, King's College London, Bessemer Road, London SE5 9PJ, UK
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de Jongh RT, Clark ADH, IJzerman RG, Serné EH, de Vries G, Stehouwer CDA. Physiological hyperinsulinaemia increases intramuscular microvascular reactive hyperaemia and vasomotion in healthy volunteers. Diabetologia 2004; 47:978-86. [PMID: 15168017 DOI: 10.1007/s00125-004-1412-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2003] [Accepted: 03/01/2004] [Indexed: 01/04/2023]
Abstract
AIMS/HYPOTHESIS Insulin possesses vasodilatory actions that may be important in regulating its access to insulin-sensitive tissues. Our study aims to directly measure changes in response to insulin in the human skeletal muscle microcirculation. Measurement was by an implanted laser Doppler probe. METHODS We investigated changes in intramuscular and skin microvascular perfusion in 12 healthy individuals during a hyperinsulinaemic and a control clamp. We determined leg blood flow with plethysmography, finger skin functional capillary recruitment with capillaroscopy, endothelium-(in)dependent vasodilation by iontophoresis of acetylcholine and sodium nitroprusside, and leg intramuscular reactive hyperaemia and vasomotion with laser Doppler measurements. RESULTS Compared to the control study, hyperinsulinaemia (416+/-82 pmol/l) caused: (i) an increase in leg blood flow (1.0+/-1.0 vs 0.1+/-0.6 ml.min(-1).100 ml, p<0.05); (ii) an increase in finger skin capillary recruitment (14.9+/-10.1 vs -5.6+/-11.0%, p<0.01); (iii) no change in baseline laser Doppler perfusion either in finger skin or leg muscle; (iv) a tendency to increase acetylcholine-mediated vasodilation (475+/-534 vs 114+/-337%, p=0.07) with no change in sodium-nitroprusside-mediated vasodilation ( p=0.2) in finger skin; (v) an increase in intramuscular reactive hyperaemia (423+/-507 vs 0+/-220%, p<0.01); and (vi) a decrease in time needed to reach peak intramuscular perfusion (-3.6+/-3.0 vs 1.1+/-3.1 s, p<0.01). In addition, hyperinsulinaemia induced an increase in intramuscular vasomotion by increasing the contribution of frequencies between 0.01 and 0.04 Hz ( p<0.05 for all), which probably represents increased endothelial and neurogenic activity. CONCLUSIONS/INTERPRETATION Physiological hyperinsulinaemia not only stimulates total blood flow and skin microvascular perfusion, but also augments human skeletal muscle microvascular recruitment and vasomotion as detected directly by laser Doppler measurements.
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Affiliation(s)
- R T de Jongh
- Department of Internal Medicine and Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, PO Box 7057, 1007 MB Amsterdam, The Netherlands
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Creager MA, Lüscher TF, Cosentino F, Beckman JA. Diabetes and vascular disease: pathophysiology, clinical consequences, and medical therapy: Part I. Circulation 2003; 108:1527-32. [PMID: 14504252 DOI: 10.1161/01.cir.0000091257.27563.32] [Citation(s) in RCA: 899] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Mark A Creager
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, Mass 02115, USA.
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26
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Laaksonen DE, Nuutinen J, Lahtinen T, Rissanen A, Niskanen LK. Changes in abdominal subcutaneous fat water content with rapid weight loss and long-term weight maintenance in abdominally obese men and women. Int J Obes (Lond) 2003; 27:677-83. [PMID: 12833111 DOI: 10.1038/sj.ijo.0802296] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Insulin resistance decreases blood flow and volume in fat tissue. We hypothesised that fat tissue nutritive blood flow and volume, and thereby water content, would increase during weight loss and weight maintenance in obese persons. DESIGN Longitudinal clinical intervention with a 9-week very-low-calorie diet (VLCD) followed by one year of weight maintenance. SUBJECTS Obese men (n=13) and women (n=14) with the metabolic syndrome. MEASUREMENTS Water content of abdominal subcutaneous fat tissue as estimated by a sensor on the skin surface measuring the dielectric constant at 300 MHz. Anthropometric measures of fatness and fat distribution. Biochemical measures related to insulin resistance. RESULTS Subjects lost 14.5+/-3.4% of body weight during the VLCD, and generally sustained this weight loss during weight maintenance. Insulin sensitivity as estimated by an index (qualitative insulin sensitivity check index) increased during the VLCD, and remained increased throughout weight maintenance. The dielectric constant increased from 23.3+/-2.3 to 25.0+/-2.1 (P<0.001) during the VLCD, and further to 27.8+/-1.9 (P<0.001) during weight maintenance, indicating an increase in the water content of subcutaneous fat. The increase in subcutaneous fat water content did not correlate with weight loss and other measures of adiposity during the VLCD, but there was an inverse correlation that strengthened in significance from baseline to 6, 9 and 12 mo (r=-0.32 to -0.64, P=0.079-0.002). Increases in subcutaneous fat water content also correlated with improvements in insulin sensitivity at 6, 9 and 12 months of weight maintenance (r=0.34-0.54, P=0.094-0.006). CONCLUSIONS Water content of abdominal subcutaneous adipose tissue increases with weight loss in obese persons with the metabolic syndrome, and may reflect increased subcutaneous fat tissue nutritive blood flow. The increase in water content correlates with the increase in insulin sensitivity, suggesting that weight loss and consequent improved insulin sensitivity could mediate the increase in abdominal subcutaneous fat hydration.
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Affiliation(s)
- D E Laaksonen
- 1Department of Medicine, Kuopio University Hospital, Kuopio, Finland
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27
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Vicent D, Ilany J, Kondo T, Naruse K, Fisher SJ, Kisanuki YY, Bursell S, Yanagisawa M, King GL, Kahn CR. The role of endothelial insulin signaling in the regulation of vascular tone and insulin resistance. J Clin Invest 2003; 111:1373-80. [PMID: 12727929 PMCID: PMC154437 DOI: 10.1172/jci15211] [Citation(s) in RCA: 261] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Insulin receptors (IRs) on vascular endothelial cells have been suggested to participate in insulin-regulated glucose homeostasis. To directly address the role of insulin action in endothelial function, we have generated a vascular endothelial cell IR knockout (VENIRKO) mouse using the Cre-loxP system. Cultured endothelium of VENIRKO mice exhibited complete rearrangement of the IR gene and a more than 95% decrease in IR mRNA. VENIRKO mice were born at the expected Mendelian ratio, grew normally, were fertile, and exhibited normal patterns of vasculature in the retina and other tissues. Glucose homeostasis under basal condition was comparable in VENIRKO mice. Both eNOS and endothelin-1 mRNA levels, however, were reduced by approximately 30-60% in endothelial cells, aorta, and heart, while vascular EGF expression was maintained at normal levels. Arterial pressure tended to be lower in VENIRKO mice on both low- and high-salt diets, and on a low-salt diet VENIRKO mice showed insulin resistance. Thus, inactivation of the IR on endothelial cell has no major consequences on vascular development or glucose homeostasis under basal conditions, but alters expression of vasoactive mediators and may play a role in maintaining vascular tone and regulation of insulin sensitivity to dietary salt intake.
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Affiliation(s)
- David Vicent
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
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Clark MG, Wallis MG, Barrett EJ, Vincent MA, Richards SM, Clerk LH, Rattigan S. Blood flow and muscle metabolism: a focus on insulin action. Am J Physiol Endocrinol Metab 2003; 284:E241-58. [PMID: 12531739 DOI: 10.1152/ajpendo.00408.2002] [Citation(s) in RCA: 237] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The vascular system controls the delivery of nutrients and hormones to muscle, and a number of hormones may act to regulate muscle metabolism and contractile performance by modulating blood flow to and within muscle. This review examines evidence that insulin has major hemodynamic effects to influence muscle metabolism. Whole body, isolated hindlimb perfusion studies and experiments with cell cultures suggest that the hemodynamic effects of insulin emanate from the vasculature itself and involve nitric oxide-dependent vasodilation at large and small vessels with the purpose of increasing access for insulin and nutrients to the interstitium and muscle cells. Recently developed techniques for detecting changes in microvascular flow, specifically capillary recruitment in muscle, indicate this to be a key site for early insulin action at physiological levels in rats and humans. In the absence of increases in bulk flow to muscle, insulin may act to switch flow from nonnutritive to the nutritive route. In addition, there is accumulating evidence to suggest that insulin resistance of muscle in vivo in terms of impaired glucose uptake could be partly due to impaired insulin-mediated capillary recruitment. Exercise training improves insulin-mediated capillary recruitment and glucose uptake by muscle.
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Affiliation(s)
- Michael G Clark
- Department of Biochemistry, Medical School, University of Tasmania, Hobart 7001, Australia.
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29
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Affiliation(s)
- John M Kinney
- Columbia University, College of Physicians and Surgeons, NY, USA
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30
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31
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Rask-Madsen C, Ihlemann N, Krarup T, Christiansen E, Kober L, Nervil Kistorp C, Torp-Pedersen C. Insulin therapy improves insulin-stimulated endothelial function in patients with type 2 diabetes and ischemic heart disease. Diabetes 2001; 50:2611-8. [PMID: 11679442 DOI: 10.2337/diabetes.50.11.2611] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Blunted insulin-stimulated endothelial function may be a mechanism for the development of atherothrombotic disease in type 2 diabetes, but it is unknown whether hypoglycemic drug therapy can modulate this abnormality. We studied patients with type 2 diabetes and stable ischemic heart disease (n = 28) and lean, healthy control subjects (n = 31). Forearm blood flow was measured by venous occlusion plethysmography during dose-response studies of acetylcholine (ACh) and sodium nitroprusside (SNP) infused into the brachial artery. In the patients and 10 healthy control subjects, ACh was repeated after intrabrachial infusion of insulin. Patients were restudied after 2 months of insulin therapy with four daily subcutaneous injections (treatment group, n = 19) or without hypoglycemic drug therapy (time control group, n = 9). Insulin infusion raised venous serum insulin in the forearm to high physiological levels (133 +/- 14.6 mU/l in patients) with a minor increase in systemic venous serum insulin. This increased the ACh response by 149 +/- 47, 110 +/- 33, 100 +/- 45, and 106 +/- 44% during the four ACh doses in healthy control subjects (P < 0.0001) but had no effect in patients (P = 0.3). After 2 months, HbA(1c) in the treatment group had decreased from 10.0 +/- 0.4 to 7.5 +/- 0.2%. Although neither the ACh response (P = 0.09) nor the SNP response (P = 0.4) had changed significantly, insulin stimulation had a significant effect, as the ACh response increased by 58 +/- 25, 84 +/- 66, 120 +/- 93, and 69 +/- 36% (P = 0.0002). In the time control group, insulin stimulation remained without effect after 8 weeks (P = 0.7). In conclusion, insulin therapy partly restores insulin-stimulated endothelial function in patients with type 2 diabetes and ischemic heart disease.
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Affiliation(s)
- C Rask-Madsen
- Department of Cardiology P, Gentofte University Hospital, Copenhagen, Denmark.
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