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Beaudry KM, Devries MC. Sex-based differences in hepatic and skeletal muscle triglyceride storage and metabolism 1. Appl Physiol Nutr Metab 2019; 44:805-813. [PMID: 30702924 DOI: 10.1139/apnm-2018-0635] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Women and men store lipid differently within the body with men storing more fat in the android region and women storing more fat in the gynoid region. Fat is predominately stored in adipose tissue as triacylglycerides (TG); however, TG are also stored in other tissues including the liver and skeletal muscle. Excess hepatic TG storage, defined as a TG concentration >5% of liver weight and known as nonalcoholic fatty liver disease (NAFLD), is related to the metabolic syndrome. Similarly, elevated skeletal muscle TG, termed intramyocellular lipids (IMCL), are related to insulin resistance in obesity and type II diabetes. Men store more hepatic TG than women and, unsurprisingly, NAFLD is more prevalent in men than women. Women store more IMCL than men, yet type II diabetes risk is not greater, which is likely due to the manner in which women store TG within muscle. Sex-based differences in TG storage between men and women are underpinned by differences in messenger RNA expression, protein content, and enzyme activities of skeletal muscle and hepatic lipid metabolic pathways. Furthermore, women have a greater reliance on lipid during exercise because of upregulation of lipid oxidative pathways. The purpose of this review is to discuss the role of sex in mediating lipid storage and metabolism within skeletal muscle and the liver at rest and during exercise and its relationship with metabolic disease.
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Affiliation(s)
- Kayleigh M Beaudry
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Michaela C Devries
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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Janssens S, Jonkers RAM, Groen AK, Nicolay K, van Loon LJC, Prompers JJ. Effects of acute exercise on lipid content and dietary lipid uptake in liver and skeletal muscle of lean and diabetic rats. Am J Physiol Endocrinol Metab 2015; 309:E874-83. [PMID: 26419590 DOI: 10.1152/ajpendo.00292.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/26/2015] [Indexed: 12/24/2022]
Abstract
Insulin resistance is associated with ectopic lipid accumulation. Physical activity improves insulin sensitivity, but the impact of exercise on lipid handling in insulin-resistant tissues remains to be elucidated. The present study characterizes the effects of acute exercise on lipid content and dietary lipid partitioning in liver and skeletal muscle of lean and diabetic rats by use of magnetic resonance spectroscopy (MRS). After baseline measurements, rats were randomized to exercise or no-exercise groups. A subset of animals was subjected to MRS directly after 1 h of treadmill running for measurement of total intrahepatocellular lipid (IHCL) and intramyocellular lipid (IMCL) content (n=7 lean and diabetic rats). The other animals were administered 13C-labeled lipids orally after treadmill visit (with or without exercise) followed by MRS measurements after 4 and 24 h to determine the 13C enrichment of IHCL and IMCL (n=8 per group). Total IHCL and IMCL content were fivefold higher in diabetic vs. lean rats (P<0.001). Exercise did not significantly affect IHCL content but reduced IMCL by 25±7 and 33±4% in lean and diabetic rats (P<0.05), respectively. Uptake of dietary lipids in liver and muscle was 2.3-fold greater in diabetic vs. lean rats (P<0.05). Prior exercise did not significantly modulate dietary lipid uptake into muscle, but in liver of both lean and diabetic rats, lipid uptake was 44% reduced after acute exercise (P<0.05). In conclusion, IMCL but not IHCL represents a viable substrate source during exercise in both lean and diabetic rats, and exercise differentially affects dietary lipid uptake in muscle and liver.
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Affiliation(s)
- Sharon Janssens
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; The Netherlands Consortium for Systems Biology, Den Haag, The Netherlands
| | - Richard A M Jonkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Albert K Groen
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; and Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Luc J C van Loon
- NUTRIM, School for Nutrition, Toxicology and Metabolism, Department of Human Movement Sciences, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands;
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Lautt WW, Ming Z, Legare DJ, Chowdhury KK, Hatch GM, Wang HH. Fatty Liver and Fatty Heart—Where do They Stand in the AMIS Syndrome? Healthcare (Basel) 2015; 3:666-82. [PMID: 27417789 PMCID: PMC4939563 DOI: 10.3390/healthcare3030666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 07/14/2015] [Accepted: 07/31/2015] [Indexed: 11/16/2022] Open
Abstract
Meal-induced insulin sensitization (MIS) refers to the augmented glucose uptake response to insulin following a meal. Absence of MIS (AMIS) causes significant decrease in post-meal glucose disposal leading to postprandial hyperglycemia, hyperinsulinemia, hyperlipidemia, adiposity, increased free radical stress, and a cluster of progressive metabolic, vascular, and cardiac dysfunctions referred to as the AMIS syndrome. We tested the hypothesis that fat accumulation in the liver and heart is part of the AMIS syndrome. Questions examined in the study: (1) Is prediabetic fat accumulation in the heart and liver a component of the AMIS syndrome? (2) Is fatty liver a cause or consequence of peripheral insulin resistance? (3) Is early cardiac dysfunction in the AMIS syndrome attributable to fat accumulation in the heart? and (4) Can the synergistic antioxidant cocktail SAMEC (S-adenosylmethionine, vitamin E, and vitamin C), known to benefit MIS, affect cardiac and hepatic triglyceride levels? Four animal models of AMIS were used in aged male Sprague-Dawley rats (52 weeks ± sucrose ± SAMEC), compared with young controls (nine weeks). Fat accumulation in the heart was not significant and therefore cannot account for the early cardiac dysfunction. Hepatic triglycerides increased only in the most severe AMIS model but the small changes correlated with the much more rapidly developing peripheral adiposity. Systemic adiposity represents an early stage, whereas accumulation of cardiac and hepatic triglycerides represents a late stage of the prediabetic AMIS syndrome. Fat accumulation in the liver is a consequence, not a cause, of AMIS. SAMEC protected against the sucrose effects on whole body adiposity and hepatic lipid accumulation.
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Affiliation(s)
- W Wayne Lautt
- Department of Pharmacology and Therapeutics, College of Medicine, Faculty of Health Sciences, University of Manitoba, A224-753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada.
| | - Zhi Ming
- Department of Pharmacology and Therapeutics, College of Medicine, Faculty of Health Sciences, University of Manitoba, A224-753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada.
| | - Dallas J Legare
- Department of Pharmacology and Therapeutics, College of Medicine, Faculty of Health Sciences, University of Manitoba, A224-753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada.
| | - Kawshik K Chowdhury
- Department of Pharmacology and Therapeutics, College of Medicine, Faculty of Health Sciences, University of Manitoba, A224-753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada.
| | - Grant M Hatch
- Department of Pharmacology and Therapeutics, College of Medicine, Faculty of Health Sciences, University of Manitoba, A224-753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada.
| | - Hui Helen Wang
- Department of Pharmacology and Therapeutics, College of Medicine, Faculty of Health Sciences, University of Manitoba, A224-753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada.
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Bilet L, Brouwers B, van Ewijk PA, Hesselink MKC, Kooi ME, Schrauwen P, Schrauwen-Hinderling VB. Acute exercise does not decrease liver fat in men with overweight or NAFLD. Sci Rep 2015; 5:9709. [PMID: 25866366 PMCID: PMC4394193 DOI: 10.1038/srep09709] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/17/2015] [Indexed: 01/05/2023] Open
Abstract
Elevated hepatic lipid content (IntraHepatic Lipid, IHL) increases the risk of metabolic complications. Although prolonged exercise training lowers IHL, it is unknown if acute exercise has the same effect. Furthermore, hepatic ATP content may be related to insulin resistance and IHL. We aimed to investigate if acute exercise leads to changes in IHL and whether this is accompanied by changes in hepatic ATP. Twenty-one men (age 54.8 ± 7.2 years, BMI 29.7 ± 2.2 kg/m2) performed a 2 h cycling protocol, once while staying fasted and once while ingesting glucose. IHL was determined at baseline, 30 min post-exercise and 4 h post-exercise. Additionally ATP/Total P ratio was measured at baseline and 4 h post-exercise. Compared with baseline values we did not observe any statistically significant changes in IHL within 30 min post-exercise in neither the fasted nor the glucose-supplemented condition. However, IHL was elevated 4 h post-exercise compared with baseline in the fasted condition (from 8.3 ± 1.8 to 8.7 ± 1.8%, p = 0.010), an effect that was blunted by glucose supplementation (from 8.3 ± 1.9 to 8.3 ± 1.9%, p = 0.789). Acute exercise does not decrease liver fat in overweight middle-aged men. Moreover, IHL increased 4 h post-exercise in the fasted condition, an increase that was absent in the glucose-supplemented condition. These data suggest that a single bout of exercise may not be able to lower IHL.
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Affiliation(s)
- L Bilet
- 1] NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands [2] Department of Human Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - B Brouwers
- 1] NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands [2] Department of Human Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - P A van Ewijk
- 1] NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands [2] Department of Human Biology, Maastricht University Medical Center, Maastricht, The Netherlands [3] Department of Radiology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - M K C Hesselink
- 1] NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands [2] Department of Human Movement Sciences, Maastricht University Medical Center, Maastricht, The Netherlands
| | - M E Kooi
- 1] NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands [2] Department of Radiology, Maastricht University Medical Center, Maastricht, The Netherlands [3] CARIM, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - P Schrauwen
- 1] NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands [2] Department of Human Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - V B Schrauwen-Hinderling
- 1] NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands [2] Department of Human Biology, Maastricht University Medical Center, Maastricht, The Netherlands [3] Department of Radiology, Maastricht University Medical Center, Maastricht, The Netherlands
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Effect of exercise training on liver antioxidant enzymes in STZ-diabetic rats. Life Sci 2015; 128:64-71. [PMID: 25744399 DOI: 10.1016/j.lfs.2015.01.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/09/2015] [Accepted: 01/31/2015] [Indexed: 12/30/2022]
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Obesity as an Early Symptom of the AMIS Syndrome. J Clin Med 2014; 3:1178-98. [PMID: 26237598 PMCID: PMC4470177 DOI: 10.3390/jcm3041178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/24/2014] [Accepted: 09/30/2014] [Indexed: 11/17/2022] Open
Abstract
We review evidence that the AMIS (Absence of Meal-induced Insulin Sensitization) syndrome describes a paradigm fundamental to development of obesity. The hypoglycemic response to a pulse of insulin is doubled after a meal as a result of Hepatic Insulin Sensitizing Substance (HISS), released from the liver to act selectively on muscle, heart and kidney. In the absence of HISS action, the hypoglycemic response to insulin is the same as in the fasted state, and only half of what it should be. Postprandial hyperglycemia ensues, with compensatory hyperinsulinemia, resultant hyperlipidemia and elevated free radical stress. Storage of nutrient energy shifts from glycogen in muscle to fat. Chronic AMIS results in adiposity, occurs with age, is accelerated with sucrose supplement, and prevented by a synergistic antioxidant. Exercise reverses AMIS, as do pharmaceuticals that mimic the "feeding signals". The AMIS syndrome develops as a sequence of pathologies based on the consequences of absence of HISS action, including adiposity as the earliest symptom. Cardiac dysfunction, hypertension, hypercholesterolemia, and fatty liver are related to lack of HISS action. The AMIS syndrome hypothesis is mechanistic-based and accounts for the major pathologies associated with prediabetes, obesity, diabetes and metabolic syndrome. AMIS can be diagnosed, prevented and treated.
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Gonçalves IO, Oliveira PJ, Ascensão A, Magalhães J. Exercise as a therapeutic tool to prevent mitochondrial degeneration in nonalcoholic steatohepatitis. Eur J Clin Invest 2013; 43:1184-94. [PMID: 24033085 DOI: 10.1111/eci.12146] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 07/27/2013] [Indexed: 12/15/2022]
Abstract
Nonalcoholic fatty liver disease, encompassing hepatic steatosis, nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis, is a significant health problem associated with modern lifestyle, based on caloric overconsumption and physical inactivity. Although the mechanisms associated with progression from the 'benign' steatosis to NASH are still elusive, mitochondrial dysfunction seems to play an important role in this degenerative process. Degeneration of mitochondrial function during NASH has been associated with impaired β-oxidation, oxidative phosphorylation and increased reactive oxygen species production, contributing to hepatocyte death and inflammatory response. Despite the fact that several therapeutic approaches can be used in the context of NASH, including insulin-sensitizing agents, anti-obesity drugs, lipid-lowering drugs or mitochondrial-targeted drugs, dietary and physical activity are still the most effective strategies. In fact, active lifestyles decrease insulin resistance and body weight and result in decreased histological signs of liver injury. In fatty liver, physical activity prevents the disease progression through mitochondrial adaptations, namely by increasing cytochrome c content, enzyme activities and fatty acid oxidation, which are lost after some days of physical inactivity. However, less is known about the effect of physical activity on NASH-associated mitochondrial dysfunction. After a brief characterization of NASH and its association with liver mitochondrial (dys)function, the present review addresses the impact of physical (in)activity on NASH and, particularly, the possible contribution of active lifestyles to the modulation of liver mitochondrial dysfunction.
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Affiliation(s)
- Inês O Gonçalves
- Research Center in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
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Comment to "serum osteopontin levels as a predictor of portal inflammation in patients with nonalcoholic fatty liver disease". Dig Liver Dis 2013; 45:783. [PMID: 23816693 DOI: 10.1016/j.dld.2013.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 02/11/2013] [Accepted: 02/15/2013] [Indexed: 12/11/2022]
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