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Stehouwer CDA. Microvascular Dysfunction and Hyperglycemia: A Vicious Cycle With Widespread Consequences. Diabetes 2018; 67:1729-1741. [PMID: 30135134 DOI: 10.2337/dbi17-0044] [Citation(s) in RCA: 176] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 06/18/2018] [Indexed: 11/13/2022]
Abstract
Microvascular and metabolic physiology are tightly linked. This Perspective reviews evidence that 1) the relationship between hyperglycemia and microvascular dysfunction (MVD) is bidirectional and constitutes a vicious cycle; 2) MVD in diabetes affects many, if not all, organs, which may play a role in diabetes-associated comorbidities such as depression and cognitive impairment; and 3) MVD precedes, and contributes to, hyperglycemia in type 2 diabetes (T2D) through impairment of insulin-mediated glucose disposal and, possibly, insulin secretion. Obesity and adverse early-life exposures are important drivers of MVD. MVD can be improved through weight loss (in obesity) and through exercise. Pharmacological interventions to improve MVD are an active area of investigation.
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Affiliation(s)
- Coen D A Stehouwer
- Department of Internal Medicine and CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre+, Maastricht, the Netherlands
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Guzik TJ, Cosentino F. Epigenetics and Immunometabolism in Diabetes and Aging. Antioxid Redox Signal 2018; 29:257-274. [PMID: 28891325 PMCID: PMC6012980 DOI: 10.1089/ars.2017.7299] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 09/04/2017] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE A strong relationship between hyperglycemia, impaired insulin pathway, and cardiovascular disease in type 2 diabetes (T2D) is linked to oxidative stress and inflammation. Immunometabolic pathways link these pathogenic processes and pose important potential therapeutic targets. Recent Advances: The link between immunity and metabolism is bidirectional and includes the role of inflammation in the pathogenesis of metabolic disorders such as T2D, obesity, metabolic syndrome, and hypertension and the role of metabolic factors in regulation of immune cell functions. Low-grade inflammation, oxidative stress, balance between superoxide and nitric oxide, and the infiltration of macrophages, T cells, and B cells in insulin-sensitive tissues lead to metabolic impairment and accelerated aging. CRITICAL ISSUES Inflammatory infiltrate and altered immune cell phenotype precede development of metabolic disorders. Inflammatory changes are tightly linked to alterations in metabolic status and energy expenditure and are controlled by epigenetic mechanisms. FUTURE DIRECTIONS A better comprehension of these mechanistic insights is of utmost importance to identify novel molecular targets. In this study, we describe a complex scenario of epigenetic changes and immunometabolism linking to diabetes and aging-associated vascular disease. Antioxid. Redox Signal. 29, 257-274.
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Affiliation(s)
- Tomasz J. Guzik
- BHF Centre for Research Excellence, Institute of Cardiovascular and Medical Research (ICAMS), University of Glasgow, Glasgow, United Kingdom
- Department of Internal and Agricultural Medicine, Laboratory of Translational Medicine, Jagiellonian University Collegium Medicum, Krakow, Poland
| | - Francesco Cosentino
- Cardiology Unit, Department of Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
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Fujita N, Aono S, Karasaki K, Sera F, Kurose T, Fujino H, Urakawa S. Changes in lipid metabolism and capillary density of the skeletal muscle following low-intensity exercise training in a rat model of obesity with hyperinsulinemia. PLoS One 2018; 13:e0196895. [PMID: 29718998 PMCID: PMC5931644 DOI: 10.1371/journal.pone.0196895] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/20/2018] [Indexed: 02/06/2023] Open
Abstract
Although exercise is effective in improving obesity and hyperinsulinemia, the exact influence of exercise on the capillary density of skeletal muscles remains unknown. The aim of this study was to investigate the effects of low-intensity exercise training on metabolism in obesity with hyperinsulinemia, focusing specifically on the capillary density within the skeletal muscle. Otsuka Long-Evans Tokushima fatty (OLETF) rats were used as animal models of obesity with hyperinsulinemia, whereas Long-Evans Tokushima Otsuka (LETO) rats served as controls (no obesity, no hyperinsulinemia). The animals were randomly assigned to either non-exercise or exercise groups (treadmill running for 60 min/day, for 4 weeks). The exercise groups were further divided into subgroups according to training mode: single bout (60 min, daily) vs. multiple bout (three bouts of 20 min, daily). Fasting insulin levels were significantly higher in OLETF than in LETO rats. Among OLETF rats, there were no significant differences in fasting glucose levels between the exercise and the non-exercise groups, but the fasting insulin levels were significantly lower in the exercise group. Body weight and triacylglycerol levels in the liver were significantly higher in OLETF than in LETO rats; however, among OLETF rats, these levels were significantly lower in the exercise than in the non-exercise group. The capillary-to-fiber ratio of the soleus muscle was significantly higher in OLETF than in LETO rats; however, among OLETF rats, the ratio was lower in the exercise group than in the non-exercise group. No significant differences in any of the studied parameters were noted between the single-bout and multiple-bout exercise training modes among either OLETF or LETO rats. These results suggest that low-intensity exercise training improves insulin sensitivity and fatty liver. Additionally, the fact that attenuation of excessive capillarization in the skeletal muscle of OLETF rats was accompanied by improvement in increased body weight.
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Affiliation(s)
- Naoto Fujita
- Department of Musculoskeletal Functional Research and Regeneration, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
- * E-mail:
| | - Saki Aono
- Department of Musculoskeletal Functional Research and Regeneration, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Kohei Karasaki
- Department of Musculoskeletal Functional Research and Regeneration, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Fumi Sera
- Department of Musculoskeletal Functional Research and Regeneration, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Tomoyuki Kurose
- Department of Musculoskeletal Functional Research and Regeneration, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Hidemi Fujino
- Life and Medical Science Area, Health Sciences Discipline, Kobe University, Suma-ku, Kobe, Japan
| | - Susumu Urakawa
- Department of Musculoskeletal Functional Research and Regeneration, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
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Lan D, Xu N, Sun J, Li Z, Liao R, Zhang H, Liang X, Yi W. Electroacupuncture mitigates endothelial dysfunction via effects on the PI3K/Akt signalling pathway in high fat diet-induced insulin-resistant rats. Acupunct Med 2018; 36:162-169. [PMID: 29502072 DOI: 10.1136/acupmed-2016-011253] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2017] [Indexed: 01/06/2023]
Abstract
OBJECTIVE To investigate the effect of electroacupuncture (EA) on endothelial dysfunction related to high fat diet (HFD)-induced insulin resistance through the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) signalling pathway. METHODS Twenty-four male Sprague-Dawley rats were fed a regular diet (Control group, n=8) or a HFD (n=16) for 12 weeks to induce an insulin resistance model. HFD-fed rats were divided into two groups that remained untreated (HFD group, n=8) or received electroacupuncture (HFD+EA group, n=8). EA was applied at PC6, ST36, SP6 and BL23. At the end of the experiment, fasting blood glucose (FBG), serum insulin (FINS), serum C-peptide (C-P) and homeostatic model assessment of insulin resistance (HOMA-IR) indices were determined. Pancreatic islet samples were subjected to histopathological examination. The thoracic aorta was immunostained with anti-rat insulin receptor substrate (IRS)-1, Akt and endothelial nitric oxide synthase (eNOS) antibodies. mRNA and protein expression of IRS-1, PI3K, Akt2 and eNOS in the vascular endothelium were determined by real-time PCR and Western blot analysis, respectively. RESULTS The bodyweight increase of the HFD+EA group was smaller than that of the untreated HFD group. Compared with the HFD group, the levels of FBG, FINS, C-P and HOMA-IR in the HFD+EA group decreased significantly (P<0.01). Histopathological evaluation indicated that EA improved pancreatic islet inflammation. The expression of endothelial markers, such as IRS-1, PI3K, Akt2 and eNOS, decreased in the HFD group, while EA treatment appeared to ameliorate the negative impact of diet. CONCLUSION EA may improve insulin resistance and attenuate endothelial dysfunction, and therefore could play a potential role in the prevention or treatment of diabetic complications and cardiovascular disease through the PI3K/Akt signalling pathway.
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Affiliation(s)
- Danchun Lan
- Department of Acupuncture and Moxibustion, Foshan Hospital of TCM, Foshan, Guangdong, China
| | - Nenggui Xu
- Clinical Medical College of Acupuncture and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jian Sun
- Department of Acupuncture and Moxibustion, Guangdong Provincial Hospital of TCM, Guangzhou, China
| | - Zhixing Li
- Department of Soft Tissue Traumatology, Shenzhen Hospital of Chinese Medicine, Shenzhen, China
| | - Rongzhen Liao
- Department of Orthopedics, The Third Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Hongtao Zhang
- Clinical Medical College of Acupuncture and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiaoli Liang
- Clinical Medical College of Acupuncture and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wei Yi
- Clinical Medical College of Acupuncture and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
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55
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Sanchez-Garcia ME, Ramirez-Lara I, Gomez-Delgado F, Yubero-Serrano EM, Leon-Acuña A, Marin C, Alcala-Diaz JF, Camargo A, Lopez-Moreno J, Perez-Martinez P, Tinahones FJ, Ordovas JM, Caballero J, Blanco-Molina A, Lopez-Miranda J, Delgado-Lista J. Evaluación cuantitativa de los cambios microvasculares capilaroscópicos en pacientes con cardiopatía isquémica establecida. Med Clin (Barc) 2018; 150:131-137. [DOI: 10.1016/j.medcli.2017.06.068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/23/2017] [Accepted: 06/08/2017] [Indexed: 11/28/2022]
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Iredahl F, Högstedt A, Henricson J, Sjöberg F, Tesselaar E, Farnebo S. Skin glucose metabolism and microvascular blood flow during local insulin delivery and after an oral glucose load. Microcirculation 2018; 23:597-605. [PMID: 27681957 DOI: 10.1111/micc.12325] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/20/2016] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Insulin causes capillary recruitment in muscle and adipose tissue, but the metabolic and microvascular effects of insulin in the skin have not been studied in detail. The aim of this study was to measure glucose metabolism and microvascular blood flow in the skin during local insulin delivery and after an oral glucose load. METHODS Microdialysis catheters were inserted intracutanously in human subjects. In eight subjects two microdialysis catheters were inserted, one perfused with insulin and one with control solution. First the local effects of insulin was studied, followed by a systemic provocation by an oral glucose load. Additionally, as control experiment, six subjects did not recieve local delivery of insulin or the oral glucose load. During microdialysis the local blood flow was measured by urea clearance and by laser speckle contrast imaging (LSCI). RESULTS Within 15 minutes of local insulin delivery, microvascular blood flow in the skin increased (urea clearance: P=.047, LSCI: P=.002) paralleled by increases in pyruvate (P=.01) and lactate (P=.04), indicating an increase in glucose uptake. An oral glucose load increased urea clearance from the catheters, indicating an increase in skin perfusion, although no perfusion changes were detected with LSCI. The concentration of glucose, pyruvate and lactate increased in the skin after the oral glucose load. CONCLUSION Insulin has metabolic and vasodilatory effects in the skin both when given locally and after systemic delivery through an oral glucose load.
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Affiliation(s)
- Fredrik Iredahl
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
| | - Alexandra Högstedt
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Joakim Henricson
- Department of Dermatology and Venerology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Folke Sjöberg
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Department of Hand Surgery, Plastic Surgery, and Burns, Linköping University, Linköping, Sweden
| | - Erik Tesselaar
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Department of Radiation Physics, Linköping University, Linköping, Sweden
| | - Simon Farnebo
- Department of Hand Surgery, Plastic Surgery, and Burns, Linköping University, Linköping, Sweden
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57
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Tan AWK, Subaran SC, Sauder MA, Chai W, Jahn LA, Fowler DE, Patrie JT, Aylor KW, Basu A, Liu Z. GLP-1 and Insulin Recruit Muscle Microvasculature and Dilate Conduit Artery Individually But Not Additively in Healthy Humans. J Endocr Soc 2018; 2:190-206. [PMID: 29568814 PMCID: PMC5841186 DOI: 10.1210/js.2017-00446] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/17/2018] [Indexed: 01/04/2023] Open
Abstract
Context Glucagon-like peptide-1 (GLP-1) and insulin increase muscle microvascular perfusion, thereby increasing tissue endothelial surface area and nutrient delivery. Objective To examine whether GLP-1 and insulin act additively on skeletal and cardiac microvasculature and conduit artery. Design Healthy adults underwent three study protocols in random order. Setting Clinical Research Unit at the University of Virginia. Methods Overnight-fasted participants received an intravenous infusion of GLP-1 (1.2 pmol/kg/min) or normal saline for 150 minutes with or without a 2-hour euglycemic insulin clamp (1 mU/kg/min) superimposed from 30 minutes onward. Skeletal and cardiac muscle microvascular blood volume (MBV), flow velocity, and flow; brachial artery diameter, flow velocity, and blood flow; and pulse wave velocity (PWV) were measured. Results GLP-1 significantly increased skeletal and cardiac muscle MBV and microvascular blood flow (MBF) after 30 minutes; these remained elevated at 150 minutes. Insulin also increased skeletal and cardiac muscle MBV and MBF. Addition of insulin to GLP-1 did not further increase skeletal and cardiac muscle MBV and MBF. GLP-1 and insulin increased brachial artery diameter and blood flow, but this effect was not additive. Neither GLP-1, insulin, nor GLP-1 and insulin altered PWV. Combined GLP-1 and insulin infusion did not result in higher whole-body glucose disposal. Conclusion GLP-1 and insulin at physiological concentrations acutely increase skeletal and cardiac muscle microvascular perfusion and dilate conduit artery in healthy adults; these effects are not additive. Thus, GLP-1 and insulin may regulate skeletal and cardiac muscle endothelial surface area and nutrient delivery under physiological conditions.
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Affiliation(s)
- Alvin W K Tan
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908.,Department of Endocrinology, Tan Tock Seng Hospital, Singapore 308433
| | - Sharmila C Subaran
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Matthew A Sauder
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Weidong Chai
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Linda A Jahn
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Dale E Fowler
- Division of Cardiovascular Medicine, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - James T Patrie
- Department of Public Health Sciences, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Kevin W Aylor
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Ananda Basu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Zhenqi Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
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Interstitial Glucose and Physical Exercise in Type 1 Diabetes: Integrative Physiology, Technology, and the Gap In-Between. Nutrients 2018; 10:nu10010093. [PMID: 29342932 PMCID: PMC5793321 DOI: 10.3390/nu10010093] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 01/11/2018] [Accepted: 01/12/2018] [Indexed: 01/06/2023] Open
Abstract
Continuous and flash glucose monitoring systems measure interstitial fluid glucose concentrations within a body compartment that is dramatically altered by posture and is responsive to the physiological and metabolic changes that enable exercise performance in individuals with type 1 diabetes. Body fluid redistribution within the interstitial compartment, alterations in interstitial fluid volume, changes in rate and direction of fluid flow between the vasculature, interstitium and lymphatics, as well as alterations in the rate of glucose production and uptake by exercising tissues, make for caution when interpreting device read-outs in a rapidly changing internal environment during acute exercise. We present an understanding of the physiological and metabolic changes taking place with acute exercise and detail the blood and interstitial glucose responses with different forms of exercise, namely sustained endurance, high-intensity, and strength exercises in individuals with type 1 diabetes. Further, we detail novel technical information on currently available patient devices. As more health services and insurance companies advocate their use, understanding continuous and flash glucose monitoring for its strengths and limitations may offer more confidence for patients aiming to manage glycemia around exercise.
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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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Irace C, Messiniti V, Tassone B, Cortese C, Barrett EJ, Gnasso A. Evidence for congruent impairment in micro and macrovascular function in type 1 diabetes. PLoS One 2017; 12:e0187525. [PMID: 29131837 PMCID: PMC5683560 DOI: 10.1371/journal.pone.0187525] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 10/21/2017] [Indexed: 01/22/2023] Open
Abstract
Diabetes affects large and small vessels through mechanisms only partially known. In the present study, we evaluated the function of capillaries and large arteries in subjects with type 1 diabetes mellitus (T1DM) to study the effect of chronic hyperglycemia in the absence of other cardiovascular risk factors. Twenty-five subjects with T1DM and 12 healthy age-matched controls were enrolled. Nine patients had mild or moderate retinopathy. Contrast enhanced ultrasound was used to measure perfusion of the deep forearm flexor muscle of the non-dominant arm at rest (baseline) and after an ischemic stimulus (reactive hyperemia). Perfusion was expressed as Video Intensity (VI) in arbitrary unit (a.u.)/mm2. The time to reach peak VI after ischemia was also recorded. The function of large arteries was evaluated using flow-mediated vasodilation (FMD). VI was significantly lower in T1DM compared to control subjects both at baseline (0.22±0.16 vs 0.44±0.35 a.u./mm2, p<0.05), and after ischemia (0.33±0.24 vs 0.68±0.46 a.u./mm2, p<0.05). The time to reach peak VI after ischemia was markedly longer in T1DM (5.6±2.2 vs 4.0±1.7 seconds, p<0.02). These differences were more marked in T1DM subjects with retinopathy. FMD was lower in TIDM patients compared to controls (5.4±6.4 vs 10.7±4.5%, p<0.01). The present findings demonstrate that T1DM patients have defective peripheral skeletal muscle perfusion both at rest and after ischemia compared with control subjects. Low muscle perfusion associates with low FMD of the brachial artery. Furthermore, T1DM subjects with retinopathy have the least muscle perfusion and blunted response to hyperemia compared to T1DM without retinopathy.
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Affiliation(s)
- Concetta Irace
- Department of Health Science, Magna Græcia University of Catanzaro, Catanzaro, Italy
| | - Valentina Messiniti
- Department of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Catanzaro, Italy
| | - Bruno Tassone
- Department of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Catanzaro, Italy
| | - Claudio Cortese
- Department of Experimental Medicine and Surgery, Tor Vergata University, Rome, Italy
| | - Eugene J. Barrett
- Division of Endocrinology, Department of Medicine, University of Virginia, School of Medicine, Charlottesville, Virginia, United States of America
| | - Agostino Gnasso
- Department of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Catanzaro, Italy
- * E-mail:
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Tejedor Jorge A. Hemodynamic and renal implications of sodium-glucose cotransporter- 2 inhibitors in type 2 diabetes mellitus. Med Clin (Barc) 2017; 147 Suppl 1:35-43. [PMID: 28760224 DOI: 10.1016/s0025-7753(17)30624-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In DM2, there is increased expression of the proximal glucose transporter SGLT2. The increased glucose reabsorption from the urine to the proximal tubule and subsequently to the bloodstream, has three direct effects on the prognosis of patients with DM2: a) it increases the daily glucose load by raising the renal threshold for glucose, thus augmenting requirements for oral antidiabetics and insulin. This progressive increase occurs throughout the course of the disease and in parallel with the increase in renal mass (renal hypertrophy); b) because of the greater glucose reabsorption, glycosuria is lower than the level corresponding to glycaemia, decreasing the stimulus on the tubuloglomerular feedback system of the distal nephron. As a result, the glomerular vasodilation caused by hyperglycaemia is not arrested, maintaining glomerular hyperfiltration, and c) the excess glucose transported to the proximal tubular cells modifies their redox status, increasing local production of glycosylating products and activating local production of proinflammatory and profibrotic proliferative mediators. These mediators are responsible for the direct free radical damage to proximal tubular cells, for increased SGLT2 expression, increased production of collagen IV and extracellular matrix, and activation of monocyte/macrophages able to cause endothelial injury. The use of SGLT2 inhibitors not only reduces the reabsorption of glucose from the glomerular filtrate back into the circulationthus improving metabolic control in diabetesbut also restores tubuloglomerular feedback by increasing glycosuria and distal urinary flow. However, the most notable effect is due to inhibition of glucose entry to the proximal tubular cells. Glycosuria is toxic to the kidney: it harms glucosetransporting cells, that is, the proximal cells, which contain SGLT2. In animal models, SGLT2 inhibition reduces local production of oxygen-free radicals, the formation of mesangial matrix and collagen IV, glomerular infiltration by inflammatory cells and monocyte/macrophage-dependent arteriosclerosis. In humans, SGLT2 have a demonstrated ability to reduce renal injury and cardiovascular risk in patients with type 2 diabetes mellitus.
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Jonasson H, Bergstrand S, Nystrom FH, Länne T, Östgren CJ, Bjarnegård N, Fredriksson I, Larsson M, Strömberg T. Skin microvascular endothelial dysfunction is associated with type 2 diabetes independently of microalbuminuria and arterial stiffness. Diab Vasc Dis Res 2017; 14:363-371. [PMID: 28482676 DOI: 10.1177/1479164117707706] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Skin and kidney microvascular functions may be affected independently in diabetes mellitus. We investigated skin microcirculatory function in 79 subjects with diabetes type 2, where 41 had microalbuminuria and 38 not, and in 41 age-matched controls. The oxygen saturation, fraction of red blood cells and speed-resolved microcirculatory perfusion (% red blood cells × mm/s) divided into three speed regions: 0-1, 1-10 and above 10 mm/s, were assessed during baseline and after local heating of the foot with a new device integrating diffuse reflectance spectroscopy and laser Doppler flowmetry. Arterial stiffness was assessed as carotid-femoral pulse wave velocity. Subjects with diabetes and microalbuminuria had significantly higher carotid-femoral pulse wave velocity compared to subjects without microalbuminuria and to controls. The perfusion for speeds 0-1 mm/s and red blood cell tissue fraction were reduced in subjects with diabetes at baseline and after heating, independent of microalbuminuria. These parameters were correlated to HbA1c. In conclusion, the reduced nutritive perfusion and red blood cell tissue fraction in type 2 diabetes were related to long-term glucose control but independent of microvascular changes in the kidneys and large-vessel stiffness. This may be due to different pathogenic pathways in the development of nephropathy, large-vessel stiffness and cutaneous microvascular impairment.
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Affiliation(s)
- Hanna Jonasson
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Sara Bergstrand
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Fredrik H Nystrom
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Toste Länne
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Carl Johan Östgren
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Niclas Bjarnegård
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Ingemar Fredriksson
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
- 3 Perimed AB, Stockholm, Sweden
| | - Marcus Larsson
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
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Endothelial and Perivascular Adipose Tissue Abnormalities in Obesity-Related Vascular Dysfunction: Novel Targets for Treatment. J Cardiovasc Pharmacol 2017; 69:360-368. [DOI: 10.1097/fjc.0000000000000469] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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65
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Ghosh A, Freestone NS, Anim-Nyame N, Arrigoni FIF. Microvascular function in pre-eclampsia is influenced by insulin resistance and an imbalance of angiogenic mediators. Physiol Rep 2017; 5:5/8/e13185. [PMID: 28455450 PMCID: PMC5408277 DOI: 10.14814/phy2.13185] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 02/06/2017] [Indexed: 12/12/2022] Open
Abstract
In preeclampsia, maternal microvascular function is disrupted and angiogenesis is dysfunctional. Insulin resistance that occurs in some pregnancies also pathologically affects microvascular function. We wished to examine the relationship of angiogenic mediators and insulin resistance on microvascular health in pregnancy. We performed a nested, case–control study of 16 women who developed preeclampsia with 17 normal pregnant controls. We hypothesized that the impaired microvascular blood flow in preeclamptic women associated with an increased ratio of the antiangiogenic factors; (s‐endoglin [sEng] and soluble fms‐like tyrosine kinase‐1 [sFlt‐1]) and proangiogenic molecule (placental growth factor [PlGF]) could be influenced by insulin resistance. Serum samples taken after 28 weeks of gestation were measured for the angiogenic factors, insulin, and glucose alongside the inflammatory marker; tumor necrosis factor‐α and endothelial activation, namely; soluble vascular cell adhesion molecule 1, intercellular adhesion molecule‐1, and e‐selectin. Maternal microvascular blood flow, measured by strain gauge plethysmography, correlated with ratios of pro‐ and antiangiogenic mediators independently of preeclampsia. Decreased microvascular function measured in preeclampsia strongly correlated with both the antiangiogenic factor (sFlt‐1 + sEng): PlGF ratio and high levels of insulin resistance, and combining insulin resistance with antiangiogenic factor ratios further strengthened this relationship. In pregnancy, microvascular blood flow is strongly associated with perturbations in pro‐ and antiangiogenic mediators. In preeclampsia, the relationship of maternal microvascular dysfunction with antiangiogenic mediators is strengthened when combined with insulin resistance.
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Affiliation(s)
- Anshuman Ghosh
- School of Life Sciences, Pharmacy and Chemistry, Kingston University London, Kingston upon Thames, UK
| | - Nicholas S Freestone
- School of Life Sciences, Pharmacy and Chemistry, Kingston University London, Kingston upon Thames, UK
| | - Nicholas Anim-Nyame
- Department of Obstetrics & Gynaecology, Kingston Hospital, Kingston upon Thames, UK
| | - Francesca I F Arrigoni
- School of Life Sciences, Pharmacy and Chemistry, Kingston University London, Kingston upon Thames, UK
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66
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Nederveen JP, Snijders T, Joanisse S, Wavell CG, Mitchell CJ, Johnston LM, Baker SK, Phillips SM, Parise G. Altered muscle satellite cell activation following 16 wk of resistance training in young men. Am J Physiol Regul Integr Comp Physiol 2016; 312:R85-R92. [PMID: 27834290 DOI: 10.1152/ajpregu.00221.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 11/02/2016] [Accepted: 11/02/2016] [Indexed: 01/07/2023]
Abstract
Skeletal muscle satellite cells (SC) play an important role in muscle adaptation. In untrained individuals, SC content and activation status have been observed to increase in response to a single bout of exercise. Muscle fiber characteristics change considerably when resistance exercise is performed chronically, but whether training status affects the activity of SC in response to a single bout of exercise remains unknown. We examined the changes in SC content and activation status following a single bout of resistance exercise, before and following a 16-wk progressive resistance training (RT) program in 14 young (25 ± 3 yr) men. Before and after RT, percutaneous biopsies from the vastus lateralis muscle were taken before a single bout of resistance exercise and after 24 and 72 h of postexercise recovery. Muscle fiber size, capillarization, and SC response were determined by immunohistochemistry. Following RT, there was a greater activation of SC after 24 h in response to a single bout of resistance exercise (Pre, 1.4 ± 0.3; 24 h, 3.1 ± 0.3 Pax7+/MyoD+ cells per 100 fibers) compared with before RT (Pre, 1.4 ± 0.3; 24 h, 2.2 ± 0.3 Pax7+/MyoD+ cells per 100 fibers, P < 0.05); no difference was observed 72 h postexercise. Following 16 wk of RT, MyoD mRNA expression increased from basal to 24 h after the single bout of exercise (P < 0.05); this change was not observed before training. Individual capillary-to-fiber ratio (C/Fi) increased in both type I (1.8 ± 0.3 to 2.0 ± 0.3 C/Fi, P < 0.05) and type II (1.7 ± 0.3 to 2.2 ± 0.3 C/Fi, P < 0.05) fibers in response to RT. After RT, enhanced activation of SC in response to resistance exercise is accompanied by increases in muscle fiber capillarization.
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Affiliation(s)
- Joshua P Nederveen
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Tim Snijders
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Sophie Joanisse
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | | | - Cameron J Mitchell
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Leeann M Johnston
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Steven K Baker
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Gianni Parise
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada; .,Department of Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada; and
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67
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Relationship of the Cold-Heat Sensation of the Limbs and Abdomen with Physiological Biomarkers. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:2718051. [PMID: 27818698 PMCID: PMC5080491 DOI: 10.1155/2016/2718051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/31/2016] [Accepted: 08/31/2016] [Indexed: 12/20/2022]
Abstract
The present study explored the relationship between the regional Cold-Heat sensation, the key indicator of the Cold-Heat patterns in traditional East Asian medicine (TEAM), and various biomarkers in Korean population. 734 apparently healthy volunteers aged 20 years and older were enrolled. Three scale self-report questions on the general thermal feel in hands, legs, and abdomen were examined. We found that 65% of women tended to perceive their body, particularly their hands and legs, to be cold, versus 25% of men. Energy expenditure and temperature load at resting state were lower in women, independently of body mass index (BMI). Those with warm hands and warm legs had a 0.74 and 0.52 kg/m2 higher BMI than those with cold hands and cold legs, respectively, regardless of age, gender, and body weight. Norepinephrine was higher, whereas the dynamic changes in glucose and insulin during an oral glucose tolerance test were lower in those with cold extremities, particularly hands. No consistent differences in biomarkers were found for the abdominal dimension. These results suggest that gender, BMI, the sympathetic nervous system, and glucose metabolism are potential determinants of the Cold-Heat sensation in the hands and legs, but not the abdomen.
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68
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Kung CP, Murphy ME. The role of the p53 tumor suppressor in metabolism and diabetes. J Endocrinol 2016; 231:R61-R75. [PMID: 27613337 PMCID: PMC5148674 DOI: 10.1530/joe-16-0324] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 09/08/2016] [Indexed: 12/12/2022]
Abstract
In the context of tumor suppression, p53 is an undisputedly critical protein. Functioning primarily as a transcription factor, p53 helps fend off the initiation and progression of tumors by inducing cell cycle arrest, senescence or programmed cell death (apoptosis) in cells at the earliest stages of precancerous development. Compelling evidence, however, suggests that p53 is involved in other aspects of human physiology, including metabolism. Indeed, recent studies suggest that p53 plays a significant role in the development of metabolic diseases, including diabetes, and further that p53's role in metabolism may also be consequential to tumor suppression. Here, we present a review of the literature on the role of p53 in metabolism, diabetes, pancreatic function, glucose homeostasis and insulin resistance. Additionally, we discuss the emerging role of genetic variation in the p53 pathway (single-nucleotide polymorphisms) on the impact of p53 in metabolic disease and diabetes. A better understanding of the relationship between p53, metabolism and diabetes may one day better inform the existing and prospective therapeutic strategies to combat this rapidly growing epidemic.
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Affiliation(s)
- Che-Pei Kung
- Department of Internal MedicineWashington University School of Medicine, St Louis, Missouri, USA
| | - Maureen E Murphy
- Department of Internal MedicineWashington University School of Medicine, St Louis, Missouri, USA
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69
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Reynolds LJ, Credeur DP, Manrique C, Padilla J, Fadel PJ, Thyfault JP. Obesity, type 2 diabetes, and impaired insulin-stimulated blood flow: role of skeletal muscle NO synthase and endothelin-1. J Appl Physiol (1985) 2016; 122:38-47. [PMID: 27789766 DOI: 10.1152/japplphysiol.00286.2016] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 02/07/2023] Open
Abstract
Increased endothelin-1 (ET-1) and reduced endothelial nitric oxide phosphorylation (peNOS) are hypothesized to reduce insulin-stimulated blood flow in type 2 diabetes (T2D), but studies examining these links in humans are limited. We sought to assess basal and insulin-stimulated endothelial signaling proteins (ET-1 and peNOS) in skeletal muscle from T2D patients. Ten obese T2D [glucose disposal rate (GDR): 6.6 ± 1.6 mg·kg lean body mass (LBM)-1·min-1] and 11 lean insulin-sensitive subjects (Lean GDR: 12.9 ± 1.2 mg·kg LBM-1·min-1) underwent a hyperinsulinemic-euglycemic clamp with vastus lateralis biopsies taken before and 60 min into the clamp. Basal biopsies were also taken in 11 medication-naïve, obese, non-T2D subjects. ET-1, peNOS (Ser1177), and eNOS protein and mRNA were measured from skeletal muscle samples containing native microvessels. Femoral artery blood flow was assessed by duplex Doppler ultrasound. Insulin-stimulated blood flow was reduced in obese T2D (Lean: +50.7 ± 6.5% baseline, T2D: +20.8 ± 5.2% baseline, P < 0.05). peNOS/eNOS content was higher in Lean under basal conditions and, although not increased by insulin, remained higher in Lean during the insulin clamp than in obese T2D (P < 0.05). ET-1 mRNA and peptide were 2.25 ± 0.50- and 1.52 ± 0.11-fold higher in obese T2D compared with Lean at baseline, and ET-1 peptide remained 2.02 ± 1.9-fold elevated in obese T2D after insulin infusion (P < 0.05) but did not increase with insulin in either group (P > 0.05). Obese non-T2D subjects tended to also display elevated basal ET-1 (P = 0.06). In summary, higher basal skeletal muscle expression of ET-1 and reduced peNOS/eNOS may contribute to a reduced insulin-stimulated leg blood flow response in obese T2D patients. NEW & NOTEWORTHY Although impairments in endothelial signaling are hypothesized to reduce insulin-stimulated blood flow in type 2 diabetes (T2D), human studies examining these links are limited. We provide the first measures of nitric oxide synthase and endothelin-1 expression from skeletal muscle tissue containing native microvessels in individuals with and without T2D before and during insulin stimulation. Higher basal skeletal muscle expression of endothelin-1 and reduced endothelial nitric oxide phosphorylation (peNOS)/eNOS may contribute to reduced insulin-stimulated blood flow in obese T2D patients.
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Affiliation(s)
- Leryn J Reynolds
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Daniel P Credeur
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Camila Manrique
- Department of Medicine-Division of Endocrinology, University of Missouri, Columbia, Missouri
| | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and.,Department of Child Health, University of Missouri, Columbia, Missouri
| | - Paul J Fadel
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and
| | - John P Thyfault
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri;
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70
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La Favor JD, Dubis GS, Yan H, White JD, Nelson MAM, Anderson EJ, Hickner RC. Microvascular Endothelial Dysfunction in Sedentary, Obese Humans Is Mediated by NADPH Oxidase: Influence of Exercise Training. Arterioscler Thromb Vasc Biol 2016; 36:2412-2420. [PMID: 27765769 DOI: 10.1161/atvbaha.116.308339] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 10/06/2016] [Indexed: 12/27/2022]
Abstract
OBJECTIVE The objectives of this study were to determine the impact of in vivo reactive oxygen species (ROS) on microvascular endothelial function in obese human subjects and the efficacy of an aerobic exercise intervention on alleviating obesity-associated dysfunctionality. APPROACH AND RESULTS Young, sedentary men and women were divided into lean (body mass index 18-25; n=14), intermediate (body mass index 28-32.5; n=13), and obese (body mass index 33-40; n=15) groups. A novel microdialysis technique was utilized to detect elevated interstitial hydrogen peroxide (H2O2) and superoxide levels in the vastus lateralis of obese compared with both lean and intermediate subjects. Nutritive blood flow was monitored in the vastus lateralis via the microdialysis-ethanol technique. A decrement in acetylcholine-stimulated blood flow revealed impaired microvascular endothelial function in the obese subjects. Perfusion of apocynin, an NADPH oxidase inhibitor, lowered (normalized) H2O2 and superoxide levels, and reversed microvascular endothelial dysfunction in obese subjects. After 8 weeks of exercise, H2O2 levels were decreased in the obese subjects and microvascular endothelial function in these subjects was restored to levels similar to lean subjects. Skeletal muscle protein expression of the NADPH oxidase subunits p22phox, p47phox, and p67phox was increased in obese relative to lean subjects, where p22phox and p67phox expression was attenuated by exercise training in obese subjects. CONCLUSIONS This study implicates NADPH oxidase as a source of excessive ROS production in skeletal muscle of obese individuals and links excessive NADPH oxidase-derived ROS to microvascular endothelial dysfunction in obesity. Furthermore, aerobic exercise training proved to be an effective strategy for alleviating these maladies.
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Affiliation(s)
- Justin D La Favor
- From the Human Performance Laboratory, Departments of Kinesiology (J.D.L.F., G.S.D., H.Y., J.D.W., R.C.H.), Pharmacology and Toxicology (M.A.M.N., E.J.A.), Physiology (R.C.H.), East Carolina Diabetes and Obesity Institute (J.D.L.F., M.A.M.N., E.J.A., R.C.H.), Center for Health Disparities (R.C.H.), East Carolina University, Greenville, NC; Department of Urology, The James Buchannan Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, MD (J.D.L.F.); Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City (E.J.A.); and Department of Biokinetics, Exercise and Leisure Science, University of KwaZulu-Natal, Durban, South Africa (R.C.H.).
| | - Gabriel S Dubis
- From the Human Performance Laboratory, Departments of Kinesiology (J.D.L.F., G.S.D., H.Y., J.D.W., R.C.H.), Pharmacology and Toxicology (M.A.M.N., E.J.A.), Physiology (R.C.H.), East Carolina Diabetes and Obesity Institute (J.D.L.F., M.A.M.N., E.J.A., R.C.H.), Center for Health Disparities (R.C.H.), East Carolina University, Greenville, NC; Department of Urology, The James Buchannan Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, MD (J.D.L.F.); Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City (E.J.A.); and Department of Biokinetics, Exercise and Leisure Science, University of KwaZulu-Natal, Durban, South Africa (R.C.H.)
| | - Huimin Yan
- From the Human Performance Laboratory, Departments of Kinesiology (J.D.L.F., G.S.D., H.Y., J.D.W., R.C.H.), Pharmacology and Toxicology (M.A.M.N., E.J.A.), Physiology (R.C.H.), East Carolina Diabetes and Obesity Institute (J.D.L.F., M.A.M.N., E.J.A., R.C.H.), Center for Health Disparities (R.C.H.), East Carolina University, Greenville, NC; Department of Urology, The James Buchannan Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, MD (J.D.L.F.); Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City (E.J.A.); and Department of Biokinetics, Exercise and Leisure Science, University of KwaZulu-Natal, Durban, South Africa (R.C.H.)
| | - Joseph D White
- From the Human Performance Laboratory, Departments of Kinesiology (J.D.L.F., G.S.D., H.Y., J.D.W., R.C.H.), Pharmacology and Toxicology (M.A.M.N., E.J.A.), Physiology (R.C.H.), East Carolina Diabetes and Obesity Institute (J.D.L.F., M.A.M.N., E.J.A., R.C.H.), Center for Health Disparities (R.C.H.), East Carolina University, Greenville, NC; Department of Urology, The James Buchannan Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, MD (J.D.L.F.); Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City (E.J.A.); and Department of Biokinetics, Exercise and Leisure Science, University of KwaZulu-Natal, Durban, South Africa (R.C.H.)
| | - Margaret A M Nelson
- From the Human Performance Laboratory, Departments of Kinesiology (J.D.L.F., G.S.D., H.Y., J.D.W., R.C.H.), Pharmacology and Toxicology (M.A.M.N., E.J.A.), Physiology (R.C.H.), East Carolina Diabetes and Obesity Institute (J.D.L.F., M.A.M.N., E.J.A., R.C.H.), Center for Health Disparities (R.C.H.), East Carolina University, Greenville, NC; Department of Urology, The James Buchannan Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, MD (J.D.L.F.); Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City (E.J.A.); and Department of Biokinetics, Exercise and Leisure Science, University of KwaZulu-Natal, Durban, South Africa (R.C.H.)
| | - Ethan J Anderson
- From the Human Performance Laboratory, Departments of Kinesiology (J.D.L.F., G.S.D., H.Y., J.D.W., R.C.H.), Pharmacology and Toxicology (M.A.M.N., E.J.A.), Physiology (R.C.H.), East Carolina Diabetes and Obesity Institute (J.D.L.F., M.A.M.N., E.J.A., R.C.H.), Center for Health Disparities (R.C.H.), East Carolina University, Greenville, NC; Department of Urology, The James Buchannan Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, MD (J.D.L.F.); Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City (E.J.A.); and Department of Biokinetics, Exercise and Leisure Science, University of KwaZulu-Natal, Durban, South Africa (R.C.H.)
| | - Robert C Hickner
- From the Human Performance Laboratory, Departments of Kinesiology (J.D.L.F., G.S.D., H.Y., J.D.W., R.C.H.), Pharmacology and Toxicology (M.A.M.N., E.J.A.), Physiology (R.C.H.), East Carolina Diabetes and Obesity Institute (J.D.L.F., M.A.M.N., E.J.A., R.C.H.), Center for Health Disparities (R.C.H.), East Carolina University, Greenville, NC; Department of Urology, The James Buchannan Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, MD (J.D.L.F.); Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City (E.J.A.); and Department of Biokinetics, Exercise and Leisure Science, University of KwaZulu-Natal, Durban, South Africa (R.C.H.)
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71
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Broussard JL, Castro AVB, Iyer M, Paszkiewicz RL, Bediako IA, Szczepaniak LS, Szczepaniak EW, Bergman RN, Kolka CM. Insulin access to skeletal muscle is impaired during the early stages of diet-induced obesity. Obesity (Silver Spring) 2016; 24:1922-8. [PMID: 27569119 PMCID: PMC5004780 DOI: 10.1002/oby.21562] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/06/2016] [Accepted: 04/28/2016] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Insulin must move from the blood to the interstitium to initiate signaling, yet access to the interstitium may be impaired in cases of insulin resistance, such as obesity. This study investigated whether consuming a short- and long-term high-fat diet (HFD) impairs insulin access to skeletal muscle, the major site of insulin-mediated glucose uptake. METHODS Male mongrel dogs were divided into three groups consisting of control diet (n = 16), short-term (n = 8), and long-term HFD (n = 8). Insulin sensitivity was measured with intravenous glucose tolerance tests. A hyperinsulinemic euglycemic clamp was performed in each animal at the conclusion of the study. During the clamp, lymph fluid was measured as a representation of the interstitial space to assess insulin access to muscle. RESULTS Short- and long-term HFD induced obesity and reduced insulin sensitivity. Lymph insulin concentrations were approximately 50% of plasma insulin concentrations under control conditions. Long-term HFD caused fasting plasma hyperinsulinemia; however, interstitial insulin concentrations were not increased, suggesting impaired insulin access to muscle. CONCLUSIONS A HFD rapidly induces insulin resistance at the muscle and impairs insulin access under basal insulin concentrations. Hyperinsulinemia induced by a long-term HFD may be a compensatory mechanism necessary to maintain healthy insulin levels in muscle interstitium.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ana V B Castro
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Malini Iyer
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | | | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
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72
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Kouw IWK, Cermak NM, Burd NA, Churchward-Venne TA, Senden JM, Gijsen AP, van Loon LJC. Sodium nitrate co-ingestion with protein does not augment postprandial muscle protein synthesis rates in older, type 2 diabetes patients. Am J Physiol Endocrinol Metab 2016; 311:E325-34. [PMID: 27221118 DOI: 10.1152/ajpendo.00122.2016] [Citation(s) in RCA: 6] [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] [Received: 03/29/2016] [Accepted: 05/19/2016] [Indexed: 12/24/2022]
Abstract
The age-related anabolic resistance to protein ingestion is suggested to be associated with impairments in insulin-mediated capillary recruitment and postprandial muscle tissue perfusion. The present study investigated whether dietary nitrate co-ingestion with protein improves muscle protein synthesis in older, type 2 diabetes patients. Twenty-four men with type 2 diabetes (72 ± 1 yr, 26.7 ± 1.4 m/kg(2) body mass index, 7.3 ± 0.4% HbA1C) received a primed continuous infusion of l-[ring-(2)H5]phenylalanine and l-[1-(13)C]leucine and ingested 20 g of intrinsically l-[1-(13)C]phenylalanine- and l-[1-(13)C]leucine-labeled protein with (PRONO3) or without (PRO) sodium nitrate (0.15 mmol/kg). Blood and muscle samples were collected to assess protein digestion and absorption kinetics and postprandial muscle protein synthesis rates. Upon protein ingestion, exogenous phenylalanine appearance rates increased in both groups (P < 0.001), resulting in 55 ± 2% and 53 ± 2% of dietary protein-derived amino acids becoming available in the circulation over the 5h postprandial period in the PRO and PRONO3 groups, respectively. Postprandial myofibrillar protein synthesis rates based on l-[ring-(2)H5]phenylalanine did not differ between groups (0.025 ± 0.004 and 0.021 ± 0.007%/h over 0-2 h and 0.032 ± 0.004 and 0.030 ± 0.003%/h over 2-5 h in PRO and PRONO3, respectively, P = 0.7). No differences in incorporation of dietary protein-derived l-[1-(13)C]phenylalanine into de novo myofibrillar protein were observed at 5 h (0.016 ± 0.002 and 0.014 ± 0.002 mole percent excess in PRO and PRONO3, respectively, P = 0.8). Dietary nitrate co-ingestion with protein does not modulate protein digestion and absorption kinetics, nor does it further increase postprandial muscle protein synthesis rates or the incorporation of dietary protein-derived amino acids into de novo myofibrillar protein in older, type 2 diabetes patients.
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Affiliation(s)
- Imre W K Kouw
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Naomi M Cermak
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Nicholas A Burd
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Tyler A Churchward-Venne
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Joan M Senden
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Annemarie P Gijsen
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Luc J C van Loon
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
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73
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Fuchs D, Nyakayiru J, Draijer R, Mulder TPJ, Hopman MTE, Eijsvogels TMH, Thijssen DH. Impact of flavonoid-rich black tea and beetroot juice on postprandial peripheral vascular resistance and glucose homeostasis in obese, insulin-resistant men: a randomized controlled trial. Nutr Metab (Lond) 2016; 13:34. [PMID: 27182277 PMCID: PMC4866334 DOI: 10.1186/s12986-016-0094-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 05/02/2016] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Insulin-stimulated muscle blood flow facilitates plasma glucose disposal after a meal, a mechanism that is impaired in obese, insulin-resistant volunteers. Nitrate- or flavonoid-rich products, through their proposed effects on nitric oxide, may improve postprandial blood flow and, subsequently, glucose disposal. To investigate whether a single dose of nitrate-rich beetroot juice or flavonoid-rich black tea lowers postprandial muscle vascular resistance in obese volunteers and alters postprandial glucose or insulin concentrations. METHOD In a randomised, controlled, cross-over study, 16 obese, insulin-resistant males consumed 75 g glucose, which was combined with 100 ml black tea, beetroot juice or control (water). Peripheral vascular resistance (VR), calculated as mean arterial pressure divided by blood flow, was assessed in the arm and leg conduit arteries, resistance arteries and muscle microcirculation across 3 h (every 30-min) after the oral glucose load. RESULTS During control, we found no postprandial response in VR in conduit, resistance and microvessels (all P > 0.05). Black tea decreased VR compared to control in conduit, resistance and microvessels (all P < 0.05). Beetroot juice decreased postprandial VR in resistance vessels, but not in conduit artery and microvessels. Although postprandial glucose response was similar after all interventions, postprandial insulin response was attenuated by ~29 % after tea (P < 0.0005), but not beetroot juice. CONCLUSIONS A single dose of black tea decreased peripheral VR across upper and lower limbs after a glucose load which was accompanied by a lower insulin response. Future studies in insulin-resistant subjects are warranted to confirm the observed effects and to explore whether long-term regular tea consumption affects glucose homeostasis. TRIAL REGISTRATION The study was registered at clinicaltrials.gov on 30(th) November 2012 (NCT01746329).
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Affiliation(s)
- Dagmar Fuchs
- />Unilever Research and Development, Vlaardingen, Olivier van Noortlaan 120, PO Box 114, 3130 AC Vlaardingen, The Netherlands
| | - Jean Nyakayiru
- />Research Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Geert Grooteplein-West 32, 6525 GA Nijmegen, The Netherlands
| | - Richard Draijer
- />Unilever Research and Development, Vlaardingen, Olivier van Noortlaan 120, PO Box 114, 3130 AC Vlaardingen, The Netherlands
| | - Theo P. J. Mulder
- />Unilever Research and Development, Vlaardingen, Olivier van Noortlaan 120, PO Box 114, 3130 AC Vlaardingen, The Netherlands
| | - Maria T. E. Hopman
- />Research Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Geert Grooteplein-West 32, 6525 GA Nijmegen, The Netherlands
| | - Thijs M. H. Eijsvogels
- />Research Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Geert Grooteplein-West 32, 6525 GA Nijmegen, The Netherlands
| | - Dick H. Thijssen
- />Research Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Geert Grooteplein-West 32, 6525 GA Nijmegen, The Netherlands
- />Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Byrom Street, L3 3AF Liverpool, UK
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Phillips BE, Atherton PJ, Varadhan K, Limb MC, Williams JP, Smith K. Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men. Appl Physiol Nutr Metab 2016; 41:548-56. [PMID: 27120341 DOI: 10.1139/apnm-2015-0543] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The anabolic effects of nutrition on skeletal muscle may depend on adequate skeletal muscle perfusion, which is impaired in older people. Cocoa flavanols have been shown to improve flow-mediated dilation, an established measure of endothelial function. However, their effect on muscle microvascular blood flow is currently unknown. Therefore, the objective of this study was to explore links between the consumption of cocoa flavanols, muscle microvascular blood flow, and muscle protein synthesis (MPS) in response to nutrition in older men. To achieve this objective, leg blood flow (LBF), muscle microvascular blood volume (MBV), and MPS were measured under postabsorptive and postprandial (intravenous Glamin (Fresenius Kabi, Germany), dextrose to sustain glucose ∼7.5 mmol·L(-1)) conditions in 20 older men. Ten of these men were studied with no cocoa flavanol intervention and a further 10 were studied with the addition of 350 mg of cocoa flavanols at the same time that nutrition began. Leg (femoral artery) blood flow was measured by Doppler ultrasound, muscle MBV by contrast-enhanced ultrasound using Definity (Lantheus Medical Imaging, Mass., USA) perflutren contrast agent and MPS using [1, 2-(13)C2]leucine tracer techniques. Our results show that although older individuals do not show an increase in LBF or MBV in response to feeding, these absent responses are apparent when cocoa flavanols are given acutely with nutrition. However, this restoration in vascular responsiveness is not associated with improved MPS responses to nutrition. We conclude that acute cocoa flavanol supplementation improves muscle macro- and microvascular responses to nutrition, independently of modifying muscle protein anabolism.
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Affiliation(s)
- Bethan E Phillips
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Philip J Atherton
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Krishna Varadhan
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Marie C Limb
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - John P Williams
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Kenneth Smith
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
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75
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Zhao HY, Li J, Xu M, Wang TG, Sun WW, Chen Y, Bi YF, Wang WQ, Ning G. Elevated whole blood viscosity is associated with insulin resistance and non-alcoholic fatty liver. Clin Endocrinol (Oxf) 2015; 83:806-11. [PMID: 25823525 DOI: 10.1111/cen.12776] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 01/08/2015] [Accepted: 03/19/2015] [Indexed: 01/06/2023]
Abstract
BACKGROUND Accumulating evidences demonstrate that abnormalities in whole blood viscosity (WBV) have been implicated in insulin resistance which may lead to non-alcoholic fatty liver disease (NAFLD). However, epidemiological studies exploring the association between WBV and NAFLD were not available. OBJECTIVE Our objective was to evaluate the association between WBV levels and risk of prevalent NAFLD. DESIGN This was a cross-sectional population-based study performed in Shanghai, China. PATIENTS A total of 8673 participants aged 40 years or older were included. MEASUREMENTS WBV was calculated from haematocrit and plasma protein concentration, at a shear rate of 208(-1) s, by a validated equation. NAFLD was diagnosed by hepatic ultrasound after the exclusion of alcohol abuse and other liver diseases. Insulin resistance (IR) was assessed by homeostasis model assessment (HOMA-IR). RESULTS The overall prevalence of NAFLD was 30·2% in this population. With the increase of WBV level, participants have larger waist circumference (WC), more severe insulin resistance and the prevalence of NAFLD increased significantly with elevated WBV quartiles. Compared with those in the lowest quartiles, adults in the highest quartile of WBV levels have higher prevalence of NAFLD (adjusted odds ratio 1·77, 95% confidence interval [CI] 1·48-2·13) and IR (2·72, 95% CI 2·26-3·27). CONCLUSIONS Elevated WBV is associated with prevalence of NAFLD and IR in middle-aged and elderly Chinese population.
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Affiliation(s)
- Hong-yan Zhao
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Jing Li
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Min Xu
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Tian-ge Wang
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Wan-wan Sun
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Ying Chen
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Yu-fang Bi
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Wei-qing Wang
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Guang Ning
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, The National Clinical Research Center for Metabolic Diseases of Ministry of Health, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, E-Institute of Shanghai Universities, Shanghai, China
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
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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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77
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Zeng C, Wei J, Yang T, Li H, Xiao WF, Luo W, Gao SG, Li YS, Xiong YL, Lei GH. Higher blood hematocrit predicts hyperuricemia: a prospective study of 62,897 person-years of follow-up. Sci Rep 2015; 5:13765. [PMID: 26337238 PMCID: PMC4559718 DOI: 10.1038/srep13765] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/20/2015] [Indexed: 01/06/2023] Open
Abstract
This prospective study aimed to investigate the relationship between higher hematocrit (Hct) level and hyperuricemia (HU) incidence. A total of 27,540 subjects were included. Baseline Hct was classified into four categories based on the quartile distribution of the study population. A cox proportional hazards regression was used to evaluate the risk of HU incidence across the Hct quartiles after adjusting a number of potential confounding factors. Out of the 62,897 person-years of follow-up, 2745 new cases of HU were developed. In models adjusted for known risk factors of HU, higher Hct was used to predict HU incidence independently in a graded manner (p = 0.02): compared with subjects in the lowest quartile, subjects in the highest quartile of Hct (hazard ratio = 1.20; 95% confidence interval: 1.03-1.41) were n20% more likely to develop HU. Sensitivity analysis indicated that the hazard ratios increased with the extension of the minimum follow-up interval. When the minimum follow-up interval was restricted to 4 years, subjects in the highest quartile of Hct were 70% more likely to develop HU, compared with the lowest quartile. Higher Hct, a routinely measured inexpensive biomarker was independently associated with the incidence of HU even within the normal range.
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Affiliation(s)
- Chao Zeng
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
| | - Jie Wei
- Department of Epidemiology and Health Statistics, School of Public Health, Central South University, Changsha, Hunan Province, China, 410008
| | - Tuo Yang
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
| | - Hui Li
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
| | - Wen-Feng Xiao
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
| | - Wei Luo
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
| | - Shu-Guang Gao
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
| | - Yu-Sheng Li
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
| | - Yi-Lin Xiong
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
| | - Guang-Hua Lei
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China, 410008
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78
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Crissey JM, Padilla J, Vieira-Potter VJ, Thorne PK, Koch LG, Britton SL, Thyfault JP, Laughlin MH. Divergent role of nitric oxide in insulin-stimulated aortic vasorelaxation between low- and high-intrinsic aerobic capacity rats. Physiol Rep 2015. [PMID: 26197933 PMCID: PMC4552535 DOI: 10.14814/phy2.12459] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Low-intrinsic aerobic capacity is associated with increased risk for cardiovascular and metabolic diseases and is a strong predictor of early mortality. The effects of intrinsic aerobic capacity on the vascular response to insulin are largely unknown. We tested the hypothesis that rats selectively bred for a low capacity to run (LCR) exhibit vascular dysfunction and impaired vascular reactivity to insulin compared to high capacity running (HCR) rats. Mature female LCR (n = 21) and HCR (n = 17) rats were maintained under sedentary conditions, and in vitro thoracic aortic vascular function was assessed. LCR exhibited greater body mass (13%), body fat (35%), and subcutaneous, perigonadal, and retroperitoneal adipose tissue mass, than HCR. During an intraperitoneal glucose tolerance test, glucose area under the curve (AUC) was not different but insulin AUC was 2-fold greater in LCR than HCR. Acetylcholine and insulin-stimulated aortic vasorelaxation was significantly greater in LCR (65.2 ± 3.8%, and 32.7 ± 4.1%) than HCR (55.0 ± 3.3%, and 16.7 ± 2.8%). Inhibition of nitric oxide synthase (NOS) with L-NAME entirely abolished insulin-mediated vasorelaxation in the aorta of LCR, with no effect in HCR. LCR rats exhibited greater expression of Insulin Receptor protein, lower Endothelin Receptor-A protein, a down-regulation of transcripts for markers of immune cell infiltration (CD11C, CD4, and F4/80) and up-regulation of pro-atherogenic inflammatory genes (VCAM-1 and MCP-1) in the aorta wall. Contrary to our hypothesis, low-aerobic capacity was associated with enhanced aortic endothelial function and NO-mediated reactivity to insulin, despite increased adiposity and evidence of whole body insulin resistance.
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Affiliation(s)
| | - Jaume Padilla
- Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri Child Health, University of Missouri, Columbia, Missouri
| | | | - Pamela K Thorne
- Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - Lauren G Koch
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan
| | - Steven L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan
| | - John P Thyfault
- Department of Molecular and Integrative Physiology, Kansas University Medical Center, Kansas, Kansas
| | - M Harold Laughlin
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri Biomedical Sciences, University of Missouri, Columbia, Missouri Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
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79
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Bradley EA, Zhang L, Genders AJ, Richards SM, Rattigan S, Keske MA. Enhancement of insulin-mediated rat muscle glucose uptake and microvascular perfusion by 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside. Cardiovasc Diabetol 2015; 14:91. [PMID: 26194188 PMCID: PMC4509722 DOI: 10.1186/s12933-015-0251-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/30/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Insulin-induced microvascular recruitment is important for optimal muscle glucose uptake. 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR, an activator of AMP-activated protein kinase), can also induce microvascular recruitment, at doses that do not acutely activate glucose transport in rat muscle. Whether low doses of AICAR can augment physiologic insulin action is unknown. In the present study we used the euglycemic hyperinsulinemic clamp to assess whether insulin action is augmented by low dose AICAR. METHODS Anesthetized rats were studied during saline infusion or euglycemic insulin (3 mU/kg/min) clamp for 2 h in the absence or presence of AICAR for the last hour (5 mg bolus followed by 3.75 mg/kg/min). Muscle glucose uptake (R'g) was determined radioisotopically with (14)C-2-deoxyglucose and muscle microvascular perfusion by contrast-enhanced ultrasound with microbubbles. RESULTS AICAR did not affect blood glucose, or lower leg R'g, although it significantly (p < 0.05) increased blood lactate levels and augmented muscle microvascular blood volume via a nitric oxide synthase dependent pathway. Insulin increased femoral blood flow, whole body glucose infusion rate (GIR), R'g, hindleg glucose uptake, and microvascular blood volume. Addition of AICAR during insulin infusion increased lactate production, further increased R'g in Type IIA (fast twitch oxidative) and IIB (fast twitch glycolytic) fiber containing muscles, and hindleg glucose uptake, but decreased R'g in the Type I (slow twitch oxidative) fiber muscle. AICAR also decreased GIR due to inhibition of insulin-mediated suppression of hepatic glucose output. AICAR augmented insulin-mediated microvascular perfusion. CONCLUSIONS AICAR, at levels that have no direct effect on muscle glucose uptake, augments insulin-mediated microvascular blood flow and glucose uptake in white fiber type muscles. Agents targeted to endothelial AMPK activation are promising insulin sensitizers, however, the decrease in GIR and the propensity to increase blood lactate cautions against AICAR as an acute insulin sensitizer.
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Affiliation(s)
- Eloise A Bradley
- Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, 7001, TAS, Australia.
| | - Lei Zhang
- Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
| | - Amanda J Genders
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia.
| | | | - Stephen Rattigan
- Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, 7001, TAS, Australia.
| | - Michelle A Keske
- Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, 7001, TAS, Australia.
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John D, Lyden K, Bassett DR. A Physiological Perspective on Treadmill and Sit-to-Stand Workstations. ERGONOMICS IN DESIGN 2015. [DOI: 10.1177/1064804615585411] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Active workstations, such as treadmill and sit-to-stand workstations, enable office employees to break prolonged sitting with bouts of light-intensity walking and/or standing. Compared with sitting, walking and/or standing accumulated during the workday using these workstations will increase muscle contractions, which may influence blood flow, energy expenditure, metabolism, musculoskeletal health, and brain function. Physiological responses when using treadmill and sit-to-stand workstations may vary due to differences in muscle contraction type (dynamic vs. static) and may thus affect cardio-metabolic and musculoskeletal health and brain function in different ways.
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81
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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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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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83
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Lambadiari V, Triantafyllou K, Dimitriadis GD. Insulin action in muscle and adipose tissue in type 2 diabetes: The significance of blood flow. World J Diabetes 2015; 6:626-633. [PMID: 25987960 PMCID: PMC4434083 DOI: 10.4239/wjd.v6.i4.626] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 12/03/2014] [Accepted: 02/11/2015] [Indexed: 02/05/2023] Open
Abstract
Under normal metabolic conditions insulin stimulates microvascular perfusion (capillary recruitment) of skeletal muscle and subcutaneous adipose tissue and thus increases blood flow mainly after meal ingestion or physical exercise. This helps the delivery of insulin itself but also that of substrates and of other signalling molecules to multiple tissues beds and facilitates glucose disposal and lipid kinetics. This effect is impaired in insulin resistance and type 2 diabetes early in the development of metabolic dysregulation and reflects early-onset endothelial dysfunction. Failure of insulin to increase muscle and adipose tissue blood flow results in decreased glucose handling. In fat depots, a blunted postprandial blood flow response will result in an insufficient suppression of lipolysis and an increased spill over of fatty acids in the circulation, leading to a more pronounced insulin resistant state in skeletal muscle. This defect in blood flow response is apparent even in the prediabetic state, implying that it is a facet of insulin resistance and exists long before overt hyperglycaemia develops. The following review intends to summarize the contribution of blood flow impairment to the development of the atherogenic dysglycemia and dyslipidaemia.
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84
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Hong YH, Betik AC, Premilovac D, Dwyer RM, Keske MA, Rattigan S, McConell GK. No effect of NOS inhibition on skeletal muscle glucose uptake during in situ hindlimb contraction in healthy and diabetic Sprague-Dawley rats. Am J Physiol Regul Integr Comp Physiol 2015; 308:R862-71. [DOI: 10.1152/ajpregu.00412.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 03/10/2015] [Indexed: 11/22/2022]
Abstract
Nitric oxide (NO) has been shown to be involved in skeletal muscle glucose uptake during contraction/exercise, especially in individuals with Type 2 diabetes (T2D). To examine the potential mechanisms, we examined the effect of local NO synthase (NOS) inhibition on muscle glucose uptake and muscle capillary blood flow during contraction in healthy and T2D rats. T2D was induced in Sprague-Dawley rats using a combined high-fat diet (23% fat wt/wt for 4 wk) and low-dose streptozotocin injections (35 mg/kg). Anesthetized animals had one hindlimb stimulated to contract in situ for 30 min (2 Hz, 0.1 ms, 35 V) with the contralateral hindlimb rested. After 10 min, the NOS inhibitor, NG-nitro-l-arginine methyl ester (l-NAME; 5 μM) or saline was continuously infused into the femoral artery of the contracting hindlimb until the end of contraction. Surprisingly, there was no increase in skeletal muscle NOS activity during contraction in either group. Local NOS inhibition had no effect on systemic blood pressure or muscle contraction force, but it did cause a significant attenuation of the increase in femoral artery blood flow in control and T2D rats. However, NOS inhibition did not attenuate the increase in muscle capillary recruitment during contraction in these rats. Muscle glucose uptake during contraction was significantly higher in T2D rats compared with controls but, unlike our previous findings in hooded Wistar rats, NOS inhibition had no effect on glucose uptake during contraction. In conclusion, NOS inhibition did not affect muscle glucose uptake during contraction in control or T2D Sprague-Dawley rats, and this may have been because there was no increase in NOS activity during contraction.
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Affiliation(s)
- Yet Hoi Hong
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Andrew C. Betik
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
| | - Dino Premilovac
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; and
| | - Renee M. Dwyer
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; and
- School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Michelle A. Keske
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; and
| | - Stephen Rattigan
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; and
| | - Glenn K. McConell
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
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85
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Phillips BE, Atherton PJ, Varadhan K, Limb MC, Wilkinson DJ, Sjøberg KA, Smith K, Williams JP. The effects of resistance exercise training on macro- and micro-circulatory responses to feeding and skeletal muscle protein anabolism in older men. J Physiol 2015; 593:2721-34. [PMID: 25867865 DOI: 10.1113/jp270343] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/07/2015] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Increases in limb blood flow in response to nutrition are reduced in older age. Muscle microvascular blood flow (MBF) in response to nutrition is also reduced with advancing age and this may contribute to age-related 'anabolic resistance'. Resistance exercise training (RET) can rejuvenate limb blood flow responses to nutrition in older individuals. We report here that 20 weeks of RET also restores muscle MBF in older individuals. Restoration of MBF does not, however, enhance muscle anabolic responses to nutrition. ABSTRACT The anabolic effects of dietary protein on skeletal muscle depend on adequate skeletal muscle perfusion, which is impaired in older people. This study explores fed state muscle microvascular blood flow, protein metabolism and exercise training status in older men. We measured leg blood flow (LBF), muscle microvascular blood volume (MBV) and muscle protein turnover under post-absorptive and fed state (i.v. Glamin to double amino acids, dextrose to sustain glucose ∼7-7.5 mmol l(-1) ) conditions in two groups: 10 untrained men (72.3 ± 1.4 years; body mass index (BMI) 26.5 ± 1.15 kg m(2) ) and 10 men who had undertaken 20 weeks of fully supervised, whole-body resistance exercise training (RET) (72.8 ± 1.4 years; BMI 26.3 ± 1.2 kg m(2) ). We measured LBF by Doppler ultrasound and muscle MBV by contrast-enhanced ultrasound. Muscle protein synthesis (MPS) was measured using [1, 2-(13) C2 ] leucine with breakdown (MPB) and net protein balance (NPB) by ring-[D5 ] phenylalanine tracers. Plasma insulin was measured via ELISA and indices of anabolic signalling (e.g. Akt/mTORC1) by immunoblotting from muscle biopsies. Whereas older untrained men did not exhibit fed-state increases in LBF or MBV, the RET group exhibited increases in both LBF and MBV. Despite our hypothesis that enhanced fed-state circulatory responses would improve anabolic responses to nutrition, fed-state increases in MPS (∼50-75%; P < 0.001) were identical in both groups. Finally, whereas only the RET group exhibited fed-state suppression of MPB (∼-38%; P < 0.05), positive NPB achieved was similar in both groups. We conclude that RET enhances fed-state LBF and MBV and restores nutrient-dependent attenuation of MPB without robustly enhancing MPS or NPB.
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Affiliation(s)
- Bethan E Phillips
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Philip J Atherton
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Krishna Varadhan
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Marie C Limb
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Daniel J Wilkinson
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Kim A Sjøberg
- University of Copenhagen, Department of Exercise and Sport Sciences, Copenhagen, Denmark
| | - Kenneth Smith
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - John P Williams
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
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Shearer J, Graham TE. Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal. Nutr Rev 2015; 72 Suppl 1:121-36. [PMID: 25293551 DOI: 10.1111/nure.12124] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
This review documents two opposing effects of caffeine and caffeine-containing energy drinks, i.e., their positive effects on athletic performance and their negative impacts on glucose tolerance in the sedentary state. Analysis of studies examining caffeine administration prior to performance-based exercise showed caffeine improved completion time by 3.6%. Similar analyses following consumption of caffeine-containing energy drinks yielded positive, but more varied, benefits, which were likely due to the diverse nature of the studies performed, the highly variable composition of the beverages consumed, and the range of caffeine doses administered. Conversely, analyses of studies administering caffeine prior to either an oral glucose tolerance test or insulin clamp showed a decline in whole-body glucose disposal of ~30%. The consequences of this resistance are unknown, but there may be implications for the development of a number of chronic diseases. Both caffeine-induced performance enhancement and insulin resistance converge with the primary actions of caffeine on skeletal muscle.
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Affiliation(s)
- Jane Shearer
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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87
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Paneni F, Costantino S, Cosentino F. Role of oxidative stress in endothelial insulin resistance. World J Diabetes 2015; 6:326-332. [PMID: 25789114 PMCID: PMC4360426 DOI: 10.4239/wjd.v6.i2.326] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/11/2014] [Accepted: 12/31/2014] [Indexed: 02/05/2023] Open
Abstract
The International Diabetes Federation estimates that 316 million people are currently affected by impaired glucose tolerance (IGT). Most importantly, recent forecasts anticipate a dramatic IGT increase with more that 470 million people affected by the year 2035. Impaired insulin sensitivity is major feature of obesity and diabetes and is strongly linked with adverse cardiometabolic phenotypes. However, the etiologic pathway linking impaired glucose tolerance and cardiovascular disease remains to be deciphered. Although insulin resistance has been attributed to inflammatory programs starting in adipose tissue, emerging evidence indicates that endothelial dysfunction may represent the upstream event preceding peripheral impairment of insulin sensitivity. Indeed, suppression of reactive oxygen species-dependent pathways in the endothelium has shown to restore insulin delivery to peripheral organs by preserving nitric oxide (NO) availability. Here we describe emerging theories concerning endothelial insulin resistance, with particular emphasis on the role oxidative stress. Complex molecular circuits including endothelial nitric oxide synthase, prostacyclin synthase, mitochondrial adaptor p66Shc, nicotinamide adenine dinucleotide phosphate-oxidase oxidase and nuclear factor kappa-B are discussed. Moreover, the review provides insights on the effectiveness of available compounds (i.e., ruboxistaurin, sildenafil, endothelin receptor antagonists, NO donors) in restoring endothelial insulin signalling. Taken together, these aspects may significantly contribute to design novel therapeutic approaches to restore glucose homeostasis in patients with obesity and diabetes.
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88
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Kolka CM, Castro AVB, Kirkman EL, Bergman RN. Modest hyperglycemia prevents interstitial dispersion of insulin in skeletal muscle. Metabolism 2015; 64:330-7. [PMID: 25468139 PMCID: PMC4277905 DOI: 10.1016/j.metabol.2014.10.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 09/22/2014] [Accepted: 10/28/2014] [Indexed: 10/24/2022]
Abstract
UNLABELLED Insulin injected directly into skeletal muscle diffuses rapidly through the interstitial space to cause glucose uptake, but this is blocked in insulin resistance. As glucotoxicity is associated with endothelial dysfunction, the observed hyperglycemia in diet-induced obese dogs may inhibit insulin access to muscle cells, and exacerbate insulin resistance. Here we asked whether interstitial insulin diffusion is reduced in modest hyperglycemia, similar to that induced by a high fat diet. METHODS During normoglycemic (100 mg/dl) and moderately hyperglycemic (120 mg/dl) clamps in anesthetized canines, sequential doses of insulin were injected into the vastus medialis of one hindlimb; the contra-lateral limb served as a control. Plasma samples were collected and analyzed for insulin content. Lymph vessels of the hind leg were also catheterized, and lymph samples were analyzed as an indicator of interstitial insulin concentration. RESULTS Insulin injection increased lymph insulin in normoglycemic animals, but not in hyperglycemic animals. Muscle glucose uptake was elevated in response to hyperglycemia, however the insulin-mediated glucose uptake in normoglycemic controls was not observed in hyperglycemia. Modest hyperglycemia prevented intra-muscularly injected insulin from diffusing through the interstitial space reduced insulin-mediated glucose uptake. CONCLUSION Hyperglycemia prevents the appearance of injected insulin in the interstitial space, thus reducing insulin action on skeletal muscle cells.
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MESH Headings
- Absorption, Physiological
- Animals
- Biological Transport/drug effects
- Diffusion
- Dogs
- Dose-Response Relationship, Drug
- Extracellular Space/chemistry
- Glucose/metabolism
- Glucose Clamp Technique
- Hindlimb
- Hyperglycemia/blood
- Hyperglycemia/drug therapy
- Hyperglycemia/metabolism
- Hyperglycemia/physiopathology
- Hypoglycemic Agents/administration & dosage
- Hypoglycemic Agents/metabolism
- Hypoglycemic Agents/pharmacokinetics
- Hypoglycemic Agents/therapeutic use
- Injections, Intramuscular
- Insulin Resistance
- Insulin, Regular, Pork/administration & dosage
- Insulin, Regular, Pork/analysis
- Insulin, Regular, Pork/pharmacokinetics
- Insulin, Regular, Pork/therapeutic use
- Lymph/chemistry
- Lymph/drug effects
- Male
- Quadriceps Muscle/chemistry
- Quadriceps Muscle/drug effects
- Quadriceps Muscle/metabolism
- Severity of Illness Index
- Tissue Distribution
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Affiliation(s)
- Cathryn M Kolka
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA.
| | - Ana Valeria B Castro
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA
| | - Erlinda L Kirkman
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA
| | - Richard N Bergman
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA
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Mitrou P, Petsiou E, Papakonstantinou E, Maratou E, Lambadiari V, Dimitriadis P, Spanoudi F, Raptis SA, Dimitriadis G. Vinegar Consumption Increases Insulin-Stimulated Glucose Uptake by the Forearm Muscle in Humans with Type 2 Diabetes. J Diabetes Res 2015; 2015:175204. [PMID: 26064976 PMCID: PMC4438142 DOI: 10.1155/2015/175204] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/07/2015] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND AND AIMS Vinegar has been shown to have a glucose-lowering effect in patients with glucose abnormalities. However, the mechanisms of this effect are still obscure. The aim of this randomised, crossover study was to investigate the effect of vinegar on glucose metabolism in muscle which is the most important tissue for insulin-stimulated glucose disposal. MATERIALS AND METHODS Eleven subjects with DM2 consumed vinegar or placebo (at random order on two separate days, a week apart), before a mixed meal. Plasma glucose, insulin, triglycerides, nonesterified fatty acids (NEFA), and glycerol were measured preprandially and at 30-60 min for 300 min postprandially from the radial artery and from a forearm vein. Muscle blood flow was measured with strain-gauge plethysmography. Glucose uptake was calculated as the arteriovenous difference of glucose multiplied by blood flow. RESULTS Vinegar compared to placebo (1) increased forearm glucose uptake (p = 0.0357), (2) decreased plasma glucose (p = 0.0279), insulin (p = 0.0457), and triglycerides (p = 0.0439), and (3) did not change NEFA and glycerol. CONCLUSIONS In DM2 vinegar reduces postprandial hyperglycaemia, hyperinsulinaemia, and hypertriglyceridaemia without affecting lipolysis. Vinegar's effect on carbohydrate metabolism may be partly accounted for by an increase in glucose uptake, demonstrating an improvement in insulin action in skeletal muscle. This trial is registered with Clinicaltrials.gov NCT02309424.
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Affiliation(s)
- Panayota Mitrou
- Hellenic National Center for Research, Prevention and Treatment of Diabetes Mellitus and Its Complications (HNDC), 3 Ploutarchou Street, 10675 Athens, Greece
- *Panayota Mitrou:
| | - Eleni Petsiou
- 2nd Department of Internal Medicine and Research Institute, Athens University Medical School, Attikon University Hospital, 1 Rimini Street, 12462 Haidari, Greece
| | - Emilia Papakonstantinou
- 2nd Department of Internal Medicine and Research Institute, Athens University Medical School, Attikon University Hospital, 1 Rimini Street, 12462 Haidari, Greece
| | - Eirini Maratou
- Hellenic National Center for Research, Prevention and Treatment of Diabetes Mellitus and Its Complications (HNDC), 3 Ploutarchou Street, 10675 Athens, Greece
| | - Vaia Lambadiari
- 2nd Department of Internal Medicine and Research Institute, Athens University Medical School, Attikon University Hospital, 1 Rimini Street, 12462 Haidari, Greece
| | - Panayiotis Dimitriadis
- Department of Water Resources and Environmental Engineering, School of Civil Engineering, NTUA, Heroon Polytechniou 5-9, 15780 Athens, Greece
| | - Filio Spanoudi
- 2nd Department of Internal Medicine and Research Institute, Athens University Medical School, Attikon University Hospital, 1 Rimini Street, 12462 Haidari, Greece
| | - Sotirios A. Raptis
- Hellenic National Center for Research, Prevention and Treatment of Diabetes Mellitus and Its Complications (HNDC), 3 Ploutarchou Street, 10675 Athens, Greece
- 2nd Department of Internal Medicine and Research Institute, Athens University Medical School, Attikon University Hospital, 1 Rimini Street, 12462 Haidari, Greece
| | - George Dimitriadis
- 2nd Department of Internal Medicine and Research Institute, Athens University Medical School, Attikon University Hospital, 1 Rimini Street, 12462 Haidari, Greece
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van Sloten TT, Henry RMA, Dekker JM, Nijpels G, Unger T, Schram MT, Stehouwer CDA. Endothelial Dysfunction Plays a Key Role in Increasing Cardiovascular Risk in Type 2 Diabetes. Hypertension 2014; 64:1299-305. [DOI: 10.1161/hypertensionaha.114.04221] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Thomas T. van Sloten
- From the Department of Medicine (T.T.v.S., R.M.A.H., M.T.S., C.D.A.S.), Cardiovascular Research Institute Maastricht (T.T.v.S., R.M.A.H., T.U., M.T.S., C.D.A.S.), and School for Nutrition, Toxicology and Metabolism (T.T.v.S.), Maastricht University Medical Centre, Maastricht, the Netherlands; and EMGO Institute for Health and Care Research (J.M.D., G.N.) and Department of Epidemiology and Biostatistics (J.M.D.), VU University Medical Centre, Amsterdam, the Netherlands
| | - Ronald M. A. Henry
- From the Department of Medicine (T.T.v.S., R.M.A.H., M.T.S., C.D.A.S.), Cardiovascular Research Institute Maastricht (T.T.v.S., R.M.A.H., T.U., M.T.S., C.D.A.S.), and School for Nutrition, Toxicology and Metabolism (T.T.v.S.), Maastricht University Medical Centre, Maastricht, the Netherlands; and EMGO Institute for Health and Care Research (J.M.D., G.N.) and Department of Epidemiology and Biostatistics (J.M.D.), VU University Medical Centre, Amsterdam, the Netherlands
| | - Jacqueline M. Dekker
- From the Department of Medicine (T.T.v.S., R.M.A.H., M.T.S., C.D.A.S.), Cardiovascular Research Institute Maastricht (T.T.v.S., R.M.A.H., T.U., M.T.S., C.D.A.S.), and School for Nutrition, Toxicology and Metabolism (T.T.v.S.), Maastricht University Medical Centre, Maastricht, the Netherlands; and EMGO Institute for Health and Care Research (J.M.D., G.N.) and Department of Epidemiology and Biostatistics (J.M.D.), VU University Medical Centre, Amsterdam, the Netherlands
| | - Giel Nijpels
- From the Department of Medicine (T.T.v.S., R.M.A.H., M.T.S., C.D.A.S.), Cardiovascular Research Institute Maastricht (T.T.v.S., R.M.A.H., T.U., M.T.S., C.D.A.S.), and School for Nutrition, Toxicology and Metabolism (T.T.v.S.), Maastricht University Medical Centre, Maastricht, the Netherlands; and EMGO Institute for Health and Care Research (J.M.D., G.N.) and Department of Epidemiology and Biostatistics (J.M.D.), VU University Medical Centre, Amsterdam, the Netherlands
| | - Thomas Unger
- From the Department of Medicine (T.T.v.S., R.M.A.H., M.T.S., C.D.A.S.), Cardiovascular Research Institute Maastricht (T.T.v.S., R.M.A.H., T.U., M.T.S., C.D.A.S.), and School for Nutrition, Toxicology and Metabolism (T.T.v.S.), Maastricht University Medical Centre, Maastricht, the Netherlands; and EMGO Institute for Health and Care Research (J.M.D., G.N.) and Department of Epidemiology and Biostatistics (J.M.D.), VU University Medical Centre, Amsterdam, the Netherlands
| | - Miranda T. Schram
- From the Department of Medicine (T.T.v.S., R.M.A.H., M.T.S., C.D.A.S.), Cardiovascular Research Institute Maastricht (T.T.v.S., R.M.A.H., T.U., M.T.S., C.D.A.S.), and School for Nutrition, Toxicology and Metabolism (T.T.v.S.), Maastricht University Medical Centre, Maastricht, the Netherlands; and EMGO Institute for Health and Care Research (J.M.D., G.N.) and Department of Epidemiology and Biostatistics (J.M.D.), VU University Medical Centre, Amsterdam, the Netherlands
| | - Coen D. A. Stehouwer
- From the Department of Medicine (T.T.v.S., R.M.A.H., M.T.S., C.D.A.S.), Cardiovascular Research Institute Maastricht (T.T.v.S., R.M.A.H., T.U., M.T.S., C.D.A.S.), and School for Nutrition, Toxicology and Metabolism (T.T.v.S.), Maastricht University Medical Centre, Maastricht, the Netherlands; and EMGO Institute for Health and Care Research (J.M.D., G.N.) and Department of Epidemiology and Biostatistics (J.M.D.), VU University Medical Centre, Amsterdam, the Netherlands
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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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93
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Triggle CR, Ding H. Cardiovascular impact of drugs used in the treatment of diabetes. Ther Adv Chronic Dis 2014; 5:245-68. [PMID: 25364492 PMCID: PMC4205571 DOI: 10.1177/2040622314546125] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The International Diabetes Federation predicts that by 2035 10% of the population of the world will have been diagnosed with diabetes, raising serious concerns over the resulting elevated morbidity and mortality as well as the impact on health care budgets. It is also well recognized that cardiovascular disease is the primary cause of the high morbidity and mortality associated with diabetes, raising the concern that appropriate drug therapy should not only correct metabolic dysfunction, but also protect the cardiovascular system from the effects of, in particular, the epigenetic changes that result from hyperglycaemia. A number of new classes of drugs for the treatment of diabetes have been introduced in the past decade, providing the opportunity to optimize treatment; however, comparative information of the cardiovascular benefits, or risks, of the newer drugs versus older therapies such as metformin is variable. This review, in addition to summarizing the cellular basis for the therapeutic action of these drugs, addresses the evidence for their cardiovascular benefits and risks. A particular focus is provided on metformin as it is the first choice drug for most patients with type 2 diabetes.
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Affiliation(s)
- Chris R Triggle
- Departments of Pharmacology and Medical Education, Weill Cornell Medical College in Qatar, PO Box 24144, Education City, Doha, Qatar
| | - Hong Ding
- Departments of Pharmacology and Medical Education, Weill Cornell Medical College in Qatar, Education City, Doha, Qatar
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Cantley JL, Vatner DF, Galbo T, Madiraju A, Petersen M, Perry RJ, Kumashiro N, Guebre-Egziabher F, Gattu AK, Stacy MR, Dione DP, Sinusas AJ, Ragolia L, Hall CE, Manchem VP, Bhanot S, Bogan JS, Samuel VT. Targeting steroid receptor coactivator 1 with antisense oligonucleotides increases insulin-stimulated skeletal muscle glucose uptake in chow-fed and high-fat-fed male rats. Am J Physiol Endocrinol Metab 2014; 307:E773-83. [PMID: 25159329 PMCID: PMC4216948 DOI: 10.1152/ajpendo.00148.2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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
The steroid receptor coactivator 1 (SRC1) regulates key metabolic pathways, including glucose homeostasis. SRC1(-/-) mice have decreased hepatic expression of gluconeogenic enzymes and a reduction in the rate of endogenous glucose production (EGP). We sought to determine whether decreasing hepatic and adipose SRC1 expression in normal adult rats would alter glucose homeostasis and insulin action. Regular chow-fed and high-fat-fed male Sprage-Dawley rats were treated with an antisense oligonucleotide (ASO) against SRC1 or a control ASO for 4 wk, followed by metabolic assessments. SRC1 ASO did not alter basal EGP or expression of gluconeogenic enzymes. Instead, SRC1 ASO increased insulin-stimulated whole body glucose disposal by ~30%, which was attributable largely to an increase in insulin-stimulated muscle glucose uptake. This was associated with an approximately sevenfold increase in adipose expression of lipocalin-type prostaglandin D2 synthase, a previously reported regulator of insulin sensitivity, and an approximately 70% increase in plasma PGD2 concentration. Muscle insulin signaling, AMPK activation, and tissue perfusion were unchanged. Although GLUT4 content was unchanged, SRC1 ASO increased the cleavage of tether-containing UBX domain for GLUT4, a regulator of GLUT4 translocation. These studies point to a novel role of adipose SRC1 as a regulator of insulin-stimulated muscle glucose uptake.
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Affiliation(s)
- Jennifer L Cantley
- Howard Hughes Medical Institute and Departments of Internal Medicine and
| | | | | | | | | | | | - Naoki Kumashiro
- Howard Hughes Medical Institute and Departments of Internal Medicine and
| | | | - Arijeet K Gattu
- Departments of Internal Medicine and West Haven Veterans Affairs Medical Center, West Haven, Connecticut
| | | | | | | | - Louis Ragolia
- Vascular Biology Institute, Winthrop-University Hospital, Mineola, New York
| | - Christopher E Hall
- Vascular Biology Institute, Winthrop-University Hospital, Mineola, New York
| | | | | | - Jonathan S Bogan
- Departments of Internal Medicine and Cell Biology, Yale School of Medicine, New Haven, Connecticut
| | - Varman T Samuel
- Departments of Internal Medicine and West Haven Veterans Affairs Medical Center, West Haven, Connecticut;
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95
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Crissey JM, Padilla J, Jenkins NT, Martin JS, Rector RS, Thyfault JP, Harold Laughlin M. Metformin does not enhance insulin-stimulated vasodilation in skeletal muscle resistance arteries of the OLETF rat. Microcirculation 2014; 20:764-75. [PMID: 23879830 DOI: 10.1111/micc.12078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 07/19/2013] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To test the hypothesis that chronic metformin treatment enhances insulin-induced vasodilation in skeletal muscle resistance arteries and arterioles. METHODS We assessed the effect of metformin treatment (from 20 to 32 weeks of age) of obese Otsuka Long Evans Tokushima Fatty (OLETF) rats and lean LETO rats (300 mg/kg) on insulin-stimulated vasodilation in isolated skeletal muscle feed arteries and arterioles. RESULTS Metformin treatment significantly lowered food intake, body weight, percent body fat, and HbA1c in OLETF rats. Metformin resulted in a ~30% reduction in insulin-induced vasodilation of soleus feed arteries (SFA) from OLETF rats. Inhibition of endothelin-1 (ET-1) signaling produced 20% dilation and eliminated the difference between metformin-treated and untreated OLETF rats in insulin-induced dilation of SFA. In contrast to the SFA, metformin did not alter insulin-stimulated vasodilation in gastrocnemius feed arteries (GFA), or second-order arterioles in the red (G2A-R) or white (G2A-W) portions of the gastrocnemius muscle of OLETF rats. Metformin had no effects on vasomotor responses of arteries from LETO. CONCLUSIONS Although metformin exerts favorable effects on body composition and HbA1c, it does not enhance the vasodilatory responses to insulin in the skeletal muscle feed arteries or arterioles of the obese OLETF rat.
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Affiliation(s)
- Jacqueline M Crissey
- Biomedical Sciences, University of Missouri, Columbia, Missouri, USA; Nutrition & Exercise Physiology, University of Missouri, Columbia, Missouri, USA
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96
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Hong YH, Betik AC, McConell GK. Role of nitric oxide in skeletal muscle glucose uptake during exercise. Exp Physiol 2014; 99:1569-73. [PMID: 25192731 DOI: 10.1113/expphysiol.2014.079202] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Nitric oxide is produced within skeletal muscle fibres and has various functions in skeletal muscle. There is evidence that NO may be essential for normal increases in skeletal muscle glucose uptake during contraction/exercise. Although there have been some discrepant results, it has been consistently demonstrated that inhibition of NO synthase (NOS) attenuates the increase in skeletal muscle glucose uptake during contraction in mouse and rat muscle ex vivo, during in situ contraction in rats and during exercise in humans. The NO-mediated increase in skeletal muscle glucose uptake during contraction/exercise is probably due to the modulation of intramuscular signalling that ultimately increases glucose transporter 4 (GLUT4) translocation and is, surprisingly, independent of blood flow. In this review, we discuss the evidence for and against a role of NO in regulating skeletal muscle glucose uptake during contraction/exercise and outline the possible mechanism(s) involved. Emerging findings regarding the role of neuronal NOS mu (nNOSμ) in this process are also discussed.
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Affiliation(s)
- Yet Hoi Hong
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia Department of Physiology, Faculty of Medicine, University of Malaya, Malaysia
| | - Andrew C Betik
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia
| | - Glenn K McConell
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia
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97
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Schreuder THA, Duncker DJ, Hopman MTE, Thijssen DHJ. Randomized controlled trial using bosentan to enhance the impact of exercise training in subjects with type 2 diabetes mellitus. Exp Physiol 2014; 99:1538-47. [PMID: 25172889 DOI: 10.1113/expphysiol.2014.081182] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In type 2 diabetes patients, endothelin (ET) receptor blockade may enhance blood flow responses to exercise training. The combination of exercise training and ET receptor blockade may represent a more potent stimulus than training alone to improve vascular function, physical fitness and glucose homeostasis. We assessed the effect of an 8 week exercise training programme combined with either ET blockade or placebo on vasculature, fitness and glucose homeostasis in people with type 2 diabetes. In a double-blind randomized controlled trial, brachial endothelium-dependent and ‑independent dilatation (using flow-mediated dilatation and glyceryl trinitrate, respectively), glucose homeostasis (using Homeostasis Model Assessment for Insulin Resistance (HOMA-IR)) and physical fitness (maximal cycling test) were assessed in 18 men with type 2 diabetes (60 ± 6 years old). Subjects underwent an 8 week exercise training programme, with half of the subjects receiving ET receptor blockade (bosentan) and the other half a placebo, followed by reassessment of the tests above. Exercise training improved physical fitness to a similar extent in both groups, but we did not detect changes in vascular function in either group. This study suggests that there is no adaptation in brachial and femoral artery endothelial function after 8 weeks of training in type 2 diabetes patients. Endothelin receptor blockade combined with exercise training does not additionally alter conduit artery endothelial function or physical fitness in type 2 diabetes.
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Affiliation(s)
- Tim H A Schreuder
- Department of Physiology, Radboud University Nijmegen Medical Centre, The Netherlands
| | - Dirk J Duncker
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Maria T E Hopman
- Department of Physiology, Radboud University Nijmegen Medical Centre, The Netherlands
| | - Dick H J Thijssen
- Department of Physiology, Radboud University Nijmegen Medical Centre, The Netherlands Division of Experimental Cardiology, Department of Cardiology, Erasmus University Medical Centre, Rotterdam, The Netherlands
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98
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Bruder-Nascimento T, da Silva MAB, Tostes RC. The involvement of aldosterone on vascular insulin resistance: implications in obesity and type 2 diabetes. Diabetol Metab Syndr 2014; 6:90. [PMID: 25352918 PMCID: PMC4210491 DOI: 10.1186/1758-5996-6-90] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/02/2014] [Indexed: 12/31/2022] Open
Abstract
Aldosterone, a mineralocorticoid hormone produced at the adrenal glands, controls corporal hydroelectrolytic balance and, consequently, has a key role in blood pressure adjustments. Aldosterone also has direct effects in many organs, including the vasculature, leading to many cellular events that influence proliferation, migration, inflammation, redox balance and apoptosis. Aldosterone effects depend on its binding to mineralocorticoid receptors (MR). Aldosterone binding to MR triggers two pathways, the genomic pathway and the non-genomic pathway. In the vasculature e.g., activation of the non-genomic pathway by aldosterone induces rapid effects that involve activation of kinases, phosphatases, transcriptional factors and NAD(P)H oxidases. Aldosterone also plays a crucial role on systemic and vascular insulin resistance, i.e. the inability of a tissue to respond to insulin. Insulin has a critical role on cell function and vascular insulin resistance is considered an early contributor to vascular damage. Accordingly, aldosterone impairs insulin receptor (IR) signaling by altering the phosphatidylinositol 3-kinase (PI3K)/nitric oxide (NO) pathway and by inducing oxidative stress and crosstalk between the IR and the insulin-like growth factor-1 receptor (IGF-1R). This mini-review focuses on the relationship between aldosterone and vascular insulin resistance. Evidence indicating MR antagonists as therapeutic tools to minimize vascular injury associated with obesity and diabetes type 2 is also discussed.
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Affiliation(s)
- Thiago Bruder-Nascimento
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av Bandeirantes 3900, Ribeirao Preto, SP 14049-900 Brazil
| | - Marcondes AB da Silva
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av Bandeirantes 3900, Ribeirao Preto, SP 14049-900 Brazil
| | - Rita C Tostes
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av Bandeirantes 3900, Ribeirao Preto, SP 14049-900 Brazil
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99
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Chai W, Zhang X, Barrett EJ, Liu Z. Glucagon-like peptide 1 recruits muscle microvasculature and improves insulin's metabolic action in the presence of insulin resistance. Diabetes 2014; 63:2788-99. [PMID: 24658303 PMCID: PMC4113068 DOI: 10.2337/db13-1597] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Glucagon-like peptide 1 (GLP-1) acutely recruits muscle microvasculature, increases muscle delivery of insulin, and enhances muscle use of glucose, independent of its effect on insulin secretion. To examine whether GLP-1 modulates muscle microvascular and metabolic insulin responses in the setting of insulin resistance, we assessed muscle microvascular blood volume (MBV), flow velocity, and blood flow in control insulin-sensitive rats and rats made insulin-resistant acutely (systemic lipid infusion) or chronically (high-fat diet [HFD]) before and after a euglycemic-hyperinsulinemic clamp (3 mU/kg/min) with or without superimposed systemic GLP-1 infusion. Insulin significantly recruited muscle microvasculature and addition of GLP-1 further expanded muscle MBV and increased insulin-mediated glucose disposal. GLP-1 infusion potently recruited muscle microvasculature in the presence of either acute or chronic insulin resistance by increasing muscle MBV. This was associated with an increased muscle delivery of insulin and muscle interstitial oxygen saturation. Muscle insulin sensitivity was completely restored in the presence of systemic lipid infusion and significantly improved in rats fed an HFD. We conclude that GLP-1 infusion potently expands muscle microvascular surface area and improves insulin's metabolic action in the insulin-resistant states. This may contribute to improved glycemic control seen in diabetic patients receiving incretin-based therapy.
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Affiliation(s)
- Weidong Chai
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, VA
| | - Xingxing Zhang
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, VADepartment of Pediatrics, Central South University 2nd Xiangya Hospital, Hunan, China
| | - Eugene J Barrett
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, VA
| | - Zhenqi Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, VA
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100
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Churchward-Venne TA, Cotie LM, MacDonald MJ, Mitchell CJ, Prior T, Baker SK, Phillips SM. Citrulline does not enhance blood flow, microvascular circulation, or myofibrillar protein synthesis in elderly men at rest or following exercise. Am J Physiol Endocrinol Metab 2014; 307:E71-83. [PMID: 24824653 DOI: 10.1152/ajpendo.00096.2014] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [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
Aging is associated with anabolic resistance, a reduced sensitivity of myofibrillar protein synthesis (MPS) to postprandial hyperaminoacidemia, particularly with low protein doses. Impairments in postprandial skeletal muscle blood flow and/or microvascular perfusion with hyperaminoacidemia and hyperinsulinemia may contribute to anabolic resistance. We examined whether providing citrulline, a precursor for arginine and nitric oxide synthesis, would increase arterial blood flow, skeletal muscle microvascular perfusion, MPS, and signaling through mTORC1. Twenty-one elderly males (65-80 yr) completed acute unilateral resistance exercise prior to being assigned to ingest a high dose (45 g) of whey protein (WHEY) or a low dose (15 g) of whey protein with 10 g of citrulline (WHEY + CIT) or with 10 g of nonessential amino acids (WHEY + NEAA). A primed, continuous infusion of L-[ring-(13)C6] phenylalanine with serial muscle biopsies was used to measure MPS and protein phosphorylation, whereas ultrasound was used to measure microvascular circulation under basal and postprandial conditions in both a rested (FED) and exercised (EX-FED) leg. Argininemia was greater in WHEY + CIT vs. WHEY and WHEY + NEAA from 30 to 300 min postexercise (P < 0.001), but there were no treatment differences in blood flow or microvascular perfusion (all P > 0.05). Phosphorylation of p70S6K-Thr(389) was greater in WHEY vs. WHEY + NEAA (P = 0.02). Postprandial MPS was greater in WHEY vs. WHEY + CIT and WHEY + NEAA under both FED (WHEY: ~128%; WHEY + CIT: ~56%; WHEY + NEAA: ~38%) and EX-FED (WHEY: ~251%; WHEY + CIT: ~124%; WHEY + NEAA: ~108%) conditions (P = 0.003). Citrulline coingestion with a low quantity of protein was ineffective in augmenting the anabolic properties of protein compared with nonessential amino acids.
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Affiliation(s)
| | | | | | | | | | - Steven K Baker
- Neurology, Exercise Metabolism Research Group, McMaster University, Hamilton, Ontario, Canada
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