1
|
Kim HJ, Kwon O. Nutrition and exercise: Cornerstones of health with emphasis on obesity and type 2 diabetes management-A narrative review. Obes Rev 2024; 25:e13762. [PMID: 38715378 DOI: 10.1111/obr.13762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 02/22/2024] [Accepted: 04/06/2024] [Indexed: 07/11/2024]
Abstract
While a broad consensus exists that integrated nutrition and regular exercise are foundational for health maintenance and serve as a robust non-pharmacological strategy against cardiometabolic diseases, the nuanced interplay between these elements remains incompletely understood. Through multifaceted interactions, these factors profoundly influence primary metabolic organs, notably the skeletal muscle and adipose tissue. Despite the critical nature of this interactivity, a holistic understanding of the combined effects of physical activity and dietary practices is still emerging. This narrative review aims to elucidate the intertwined roles of nutrition and exercise. It provides a comprehensive overview of their synergistic dynamics and emphasizes the importance of a dual-focus approach in mitigating and managing cardiometabolic disorders, predominantly obesity and type 2 diabetes.
Collapse
Affiliation(s)
- Hye Jin Kim
- Laboratory of Developmental Biology and Genomics, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Korea Mouse Phenotyping Center (KMPC), Seoul, Republic of Korea
- Logme Inc., Seoul, Republic of Korea
| | - Oran Kwon
- Logme Inc., Seoul, Republic of Korea
- Department of Nutritional Science and Food Management, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, Republic of Korea
| |
Collapse
|
2
|
Alqallaf J, Orange ST, Matu J, Griffiths A, Johnson K, Stavropoulos-Kalinoglou A, Holliday A, Wilson O. The Effect of High-Fat Diet on Intramyocellular Lipid Content in Healthy Adults: A Systematic Review, Meta-Analysis, and Meta-Regression. J Nutr 2024; 154:1087-1100. [PMID: 38417551 PMCID: PMC11007750 DOI: 10.1016/j.tjnut.2024.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 03/01/2024] Open
Abstract
Fatty acids are stored within the muscle as intramyocellular lipids (IMCL). Some, but not all, studies indicate that following a high-fat diet (HFD), IMCL may accumulate and affect insulin sensitivity. This systematic review and meta-analysis aimed to quantify the effects of an HFD on IMCL. It also explored the potential modifying effects of HFD fat content and duration, IMCL measurement technique, physical activity status, and the associations of IMCL with insulin sensitivity. Five databases were systematically searched for studies that examined the effect of ≥3 d of HFD (>35% daily energy intake from fat) on IMCL content in healthy individuals. Meta-regressions were used to investigate associations of the HFD total fat content, duration, physical activity status, IMCL measurement technique, and insulin sensitivity with IMCL responses. Changes in IMCL content and insulin sensitivity (assessed by hyperinsulinemic-euglycemic clamp) are presented as standardized mean difference (SMD) using a random effects model with 95% confidence intervals (95% CIs). Nineteen studies were included in the systematic review and 16 in the meta-analysis. IMCL content increased following HFD (SMD = 0.63; 95% CI: 0.31, 0.94, P = 0.001). IMCL accumulation was not influenced by total fat content (P = 0.832) or duration (P = 0.844) of HFD, physical activity status (P = 0.192), or by the IMCL measurement technique (P > 0.05). Insulin sensitivity decreased following HFD (SMD = -0.34; 95% CI: -0.52, -0.16; P = 0.003), but this was not related to the increase in IMCL content following HFD (P = 0.233). Consumption of an HFD (>35% daily energy intake from fat) for ≥3 d significantly increases IMCL content in healthy individuals regardless of HFD total fat content and duration of physical activity status. All IMCL measurement techniques detected the increased IMCL content following HFD. The dissociation between changes in IMCL and insulin sensitivity suggests that other factors may drive HFD-induced impairments in insulin sensitivity in healthy individuals. This trial was registered at PROSPERO as CRD42021257984.
Collapse
Affiliation(s)
- Jasem Alqallaf
- Carnegie School of Sport, Leeds Beckett University, United Kingdom
| | - Samuel T Orange
- School of Biomedical, Nutritional, and Sport Sciences, Faculty of Medical Sciences, Newcastle University, United Kingdom; Newcastle University Centre for Cancer, Newcastle University, United Kingdom
| | - Jamie Matu
- School of Health, Leeds Beckett University, United Kingdom
| | - Alex Griffiths
- School of Health, Leeds Beckett University, United Kingdom
| | - Kelsie Johnson
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, United Kingdom
| | | | - Adrian Holliday
- School of Biomedical, Nutritional, and Sport Sciences, Faculty of Medical Sciences, Newcastle University, United Kingdom
| | - Oliver Wilson
- Carnegie School of Sport, Leeds Beckett University, United Kingdom.
| |
Collapse
|
3
|
Ashcroft SP, Stocks B, Egan B, Zierath JR. Exercise induces tissue-specific adaptations to enhance cardiometabolic health. Cell Metab 2024; 36:278-300. [PMID: 38183980 DOI: 10.1016/j.cmet.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 10/06/2023] [Accepted: 12/05/2023] [Indexed: 01/08/2024]
Abstract
The risk associated with multiple cancers, cardiovascular disease, diabetes, and all-cause mortality is decreased in individuals who meet the current recommendations for physical activity. Therefore, regular exercise remains a cornerstone in the prevention and treatment of non-communicable diseases. An acute bout of exercise results in the coordinated interaction between multiple tissues to meet the increased energy demand of exercise. Over time, the associated metabolic stress of each individual exercise bout provides the basis for long-term adaptations across tissues, including the cardiovascular system, skeletal muscle, adipose tissue, liver, pancreas, gut, and brain. Therefore, regular exercise is associated with a plethora of benefits throughout the whole body, including improved cardiorespiratory fitness, physical function, and glycemic control. Overall, we summarize the exercise-induced adaptations that occur within multiple tissues and how they converge to ultimately improve cardiometabolic health.
Collapse
Affiliation(s)
- Stephen P Ashcroft
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ben Stocks
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Brendan Egan
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Juleen R Zierath
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Integrative Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
| |
Collapse
|
4
|
Knudsen CB, Nielsen J, Ørtenblad N, Mohr M, Overgaard K, Vigh-Larsen JF. No net utilization of intramuscular lipid droplets during repeated high-intensity intermittent exercise. Am J Physiol Endocrinol Metab 2023; 325:E700-E710. [PMID: 37877795 DOI: 10.1152/ajpendo.00298.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 10/26/2023]
Abstract
Intramuscular lipids are stored as subsarcolemmal or intramyofibrillar droplets with potential diverse roles in energy metabolism. We examined intramuscular lipid utilization through transmission electron microscopy during repeated high-intensity intermittent exercise, an aspect that is hitherto unexplored. Seventeen moderately to well-trained males underwent three periods (EX1-EX3) of 10 × 45-s high-intensity cycling [∼100%-120% Wattmax (Wmax)] combined with maximal repeated sprints (∼250%-300% Wmax). M. vastus lateralis biopsies were obtained at baseline, after EX1, and EX3. During the complete exercise session, no net decline in either subsarcolemmal or intermyofibrillar lipid volume density occurred. However, a temporal relationship emerged for subsarcolemmal lipids with an ∼11% increase in droplet size after EX1 (P = 0.024), which reverted to baseline levels after EX3 accompanied by an ∼30% reduction in the numerical density of subsarcolemmal lipid droplets compared with both baseline (P = 0.019) and after EX1 (P = 0.018). Baseline distinctions were demonstrated with an approximately twofold higher intermyofibrillar lipid volume in type 1 versus type 2 fibers (P = 0.008), mediated solely by a higher number rather than the size of lipid droplets (P < 0.001). No fiber-type-specific differences were observed in subsarcolemmal lipid volume although type 2 fibers exhibited ∼17% larger droplets (P = 0.034) but a lower numerical density (main effect; P = 0.010) including 3% less droplets at baseline. Collectively, these findings suggest that intramuscular lipids do not serve as an important substrate during high-intensity intermittent exercise; however, the repeated exercise pattern mediated a temporal remodeling of the subsarcolemmal lipid pool. Furthermore, fiber-type- and compartment-specific differences were found at baseline underscoring the heterogeneity in lipid droplet deposition.NEW & NOTEWORTHY Undertaking a severe repeated high-intensity intermittent exercise protocol led to no net decline in neither subsarcolemmal nor intermyofibrillar lipid content in the thigh muscle of young moderately to well-trained participants. However, a temporal remodeling of the subsarcolemmal pool of lipid droplets did occur indicative of potential transient lipid accumulation. Moreover, baseline fiber-type distinctions in subcellular lipid droplet deposition were present underscoring the diversity in lipid droplet storage among fiber types and subcellular regions.
Collapse
Affiliation(s)
- Christian B Knudsen
- Department of Public Health, Research Unit for Exercise Biology, Aarhus University, Aarhus, Denmark
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Magni Mohr
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
- Centre of Health Science, University of the Faroe Islands, Tórshavn, Faroe Islands
| | - Kristian Overgaard
- Department of Public Health, Research Unit for Exercise Biology, Aarhus University, Aarhus, Denmark
| | - Jeppe F Vigh-Larsen
- Department of Public Health, Research Unit for Exercise Biology, Aarhus University, Aarhus, Denmark
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| |
Collapse
|
5
|
Bajpeyi S, Apaflo JN, Rosas V, Sepulveda-Rivera K, Varela-Ramirez A, Covington JD, Galgani JE, Ravussin E. Effect of an acute long-duration exercise bout on skeletal muscle lipid droplet morphology, GLUT 4 protein, and perilipin protein expression. Eur J Appl Physiol 2023; 123:2771-2778. [PMID: 37368137 DOI: 10.1007/s00421-023-05266-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 06/21/2023] [Indexed: 06/28/2023]
Abstract
PURPOSE Smaller lipid droplet morphology and GLUT 4 protein expression have been associated with greater muscle oxidative capacity and glucose uptake, respectively. The main purpose of this study was to determine the effect of an acute long-duration exercise bout on skeletal muscle lipid droplet morphology, GLUT4, perilipin 3, and perilipin 5 expressions. METHODS Twenty healthy men (age 24.0 ± 1.0 years, BMI 23.6 ± 0.4 kg/m2) were recruited for the study. The participants were subjected to an acute bout of exercise on a cycle ergometer at 50% VO2max until they reached a total energy expenditure of 650 kcal. The study was conducted after an overnight fast. Vastus lateralis muscle biopsies were obtained before and immediately after exercise for immunohistochemical analysis to determine lipid, perilipin 3, perilipin 5, and GLUT4 protein contents while GLUT 4 mRNA was quantified using RT-qPCR. RESULTS Lipid droplet size decreased whereas total intramyocellular lipid content tended to reduce (p = 0.07) after an acute bout of endurance exercise. The density of smaller lipid droplets in the peripheral sarcoplasmic region significantly increased (0.584 ± 0.04 to 0.638 ± 0.08 AU; p = 0.01) while larger lipid droplets significantly decreased (p < 0.05). GLUT4 mRNA tended to increase (p = 0.05). There were no significant changes in GLUT 4, perilipin 3, and perilipin 5 protein levels. CONCLUSION The study demonstrates that exercise may impact metabolism by enhancing the quantity of smaller lipid droplets over larger lipid droplets.
Collapse
Affiliation(s)
- Sudip Bajpeyi
- Metabolic, Nutrition, and Exercise Research (MiNER) Laboratory, Department of Kinesiology, The University of Texas at El Paso, 500 University Ave, El Paso, TX, 79968, USA.
| | - Jehu N Apaflo
- Metabolic, Nutrition, and Exercise Research (MiNER) Laboratory, Department of Kinesiology, The University of Texas at El Paso, 500 University Ave, El Paso, TX, 79968, USA
| | - Victoria Rosas
- Metabolic, Nutrition, and Exercise Research (MiNER) Laboratory, Department of Kinesiology, The University of Texas at El Paso, 500 University Ave, El Paso, TX, 79968, USA
| | - Keisha Sepulveda-Rivera
- Metabolic, Nutrition, and Exercise Research (MiNER) Laboratory, Department of Kinesiology, The University of Texas at El Paso, 500 University Ave, El Paso, TX, 79968, USA
| | - Armando Varela-Ramirez
- The Cellular Characterization and Biorepository (CCB) Core Facility, Border Biomedical Research Center, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, USA
| | - Jeffrey D Covington
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Jose E Galgani
- Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Eric Ravussin
- Laboratory of Skeletal Muscle Physiology, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| |
Collapse
|
6
|
Smith JAB, Murach KA, Dyar KA, Zierath JR. Exercise metabolism and adaptation in skeletal muscle. Nat Rev Mol Cell Biol 2023; 24:607-632. [PMID: 37225892 PMCID: PMC10527431 DOI: 10.1038/s41580-023-00606-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2023] [Indexed: 05/26/2023]
Abstract
Viewing metabolism through the lens of exercise biology has proven an accessible and practical strategy to gain new insights into local and systemic metabolic regulation. Recent methodological developments have advanced understanding of the central role of skeletal muscle in many exercise-associated health benefits and have uncovered the molecular underpinnings driving adaptive responses to training regimens. In this Review, we provide a contemporary view of the metabolic flexibility and functional plasticity of skeletal muscle in response to exercise. First, we provide background on the macrostructure and ultrastructure of skeletal muscle fibres, highlighting the current understanding of sarcomeric networks and mitochondrial subpopulations. Next, we discuss acute exercise skeletal muscle metabolism and the signalling, transcriptional and epigenetic regulation of adaptations to exercise training. We address knowledge gaps throughout and propose future directions for the field. This Review contextualizes recent research of skeletal muscle exercise metabolism, framing further advances and translation into practice.
Collapse
Affiliation(s)
- Jonathon A B Smith
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Kevin A Murach
- Molecular Mass Regulation Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Kenneth A Dyar
- Metabolic Physiology, Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Juleen R Zierath
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
7
|
Stokie JR, Abbott G, Howlett KF, Hamilton DL, Shaw CS. Intramuscular lipid utilization during exercise: a systematic review, meta-analysis, and meta-regression. J Appl Physiol (1985) 2023; 134:581-592. [PMID: 36656983 DOI: 10.1152/japplphysiol.00637.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Intramuscular lipid (IMCL) utilization during exercise was controversial as numerous studies did not observe a decline in IMCL content post-exercise when assessed in muscle biopsies using biochemical techniques. Contemporary techniques including immunofluorescence microscopy and 1H-magnetic resonance spectroscopy (1H-MRS) offer advantages over biochemical techniques. The primary aim of this systematic review, meta-analysis, and meta-regression was to examine the net degradation of IMCL in response to an acute bout of cycling exercise in humans, as assessed with different analytical approaches. A secondary aim was to explore the factors influencing IMCL degradation including feeding status, exercise variables, and participant characteristics. A total of 44 studies met the inclusion criteria using biochemical, immunofluorescence, and 1H-MRS techniques. A meta-analysis was completed using a random effects model and percentage change in IMCL content calculated from the standardized mean difference. Cycling exercise resulted in a net degradation of IMCL regardless of technique (total effect -23.7%, 95% CI = -28.7 to -18.7%) and there was no difference when comparing fasted versus fed-state exercise (P > 0.05). IMCL degradation using immunofluorescence techniques detected larger effects in type I fibers compared with whole muscle using biochemical techniques (P = 0.003) and in type I fibers compared with type II fibers (P < 0.001). Although IMCL degradation was associated with exercise duration, V̇o2max, and BMI, none of these factors independently related to the change in IMCL content. These findings provide strong evidence that the analytical approach can influence the assessment of IMCL degradation in human skeletal muscle in response to exercise.
Collapse
Affiliation(s)
- Jayden R Stokie
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Gavin Abbott
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Kirsten F Howlett
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - David L Hamilton
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Christopher S Shaw
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| |
Collapse
|
8
|
Kirwan R. Differential effects of vitamin D on upper and lower body fat-free mass: potential mechanisms. Mol Biol Rep 2023; 50:883-888. [PMID: 36352180 PMCID: PMC9646270 DOI: 10.1007/s11033-022-07998-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 09/30/2022] [Indexed: 11/10/2022]
Abstract
Vitamin D insufficiency is a global health concern and low vitamin D status is regularly associated with reduced muscle mass and sarcopenia in observational research. Recent research using Mendelian randomization (MR) has highlighted the potentially causal positive effect of serum vitamin D (25(OH)D) on total, trunk and upper body appendicular fat-free mass (FFM). However, no such effect was found in lower body FFM, a result that mirrors the outcomes of some vitamin D intervention studies. Here we review the current literature on vitamin D, muscle mass and strength and discuss some potential mechanisms for the differing effects of vitamin D on upper and lower body FFM. In particular, differences in distribution of the vitamin D receptor as well as androgen receptors, in the upper and lower body musculature, will be discussed.
Collapse
Affiliation(s)
- Richard Kirwan
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.
| |
Collapse
|
9
|
Barrett JS, Whytock KL, Strauss JA, Wagenmakers AJM, Shepherd SO. High intramuscular triglyceride turnover rates and the link to insulin sensitivity: influence of obesity, type 2 diabetes and physical activity. Appl Physiol Nutr Metab 2022; 47:343-356. [PMID: 35061523 DOI: 10.1139/apnm-2021-0631] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Large intramuscular triglyceride (IMTG) stores in sedentary, obese individuals have been linked to insulin resistance, yet well-trained athletes exhibit high IMTG levels whilst maintaining insulin sensitivity. Contrary to previous assumptions, it is now known that IMTG content per se does not result in insulin resistance. Rather, insulin resistance is caused, at least in part, by the presence of high concentrations of harmful lipid metabolites, such as diacylglycerols and ceramides in muscle. Several mechanistic differences between obese sedentary individuals and their highly trained counterparts have been identified, which determine the differential capacity for IMTG synthesis and breakdown in these populations. In this review, we first describe the most up-to-date mechanisms by which a low IMTG turnover rate (both breakdown and synthesis) leads to the accumulation of lipid metabolites and results in skeletal muscle insulin resistance. We then explore current and potential exercise and nutritional strategies that target IMTG turnover in sedentary obese individuals, to improve insulin sensitivity. Overall, improving IMTG turnover should be an important component of successful interventions that aim to prevent the development of insulin resistance in the ever-expanding sedentary, overweight and obese populations. Novelty: A description of the most up-to-date mechanisms regulating turnover of the IMTG pool. An exploration of current and potential exercise/nutritional strategies to target and enhance IMTG turnover in obese individuals. Overall, highlights the importance of improving IMTG turnover to prevent the development of insulin resistance.
Collapse
Affiliation(s)
- J S Barrett
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - K L Whytock
- Translational Research Institute, AdventHealth, Orlando, FL 32804, USA
| | - J A Strauss
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - A J M Wagenmakers
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - S O Shepherd
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| |
Collapse
|
10
|
Pathophysiology of Lipid Droplets in Neuroglia. Antioxidants (Basel) 2021; 11:antiox11010022. [PMID: 35052526 PMCID: PMC8773017 DOI: 10.3390/antiox11010022] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 12/12/2022] Open
Abstract
In recent years, increasing evidence regarding the functional importance of lipid droplets (LDs), cytoplasmic storage organelles in the central nervous system (CNS), has emerged. Although not abundantly present in the CNS under normal conditions in adulthood, LDs accumulate in the CNS during development and aging, as well as in some neurologic disorders. LDs are actively involved in cellular lipid turnover and stress response. By regulating the storage of excess fatty acids, cholesterol, and ceramides in addition to their subsequent release in response to cell needs and/or environmental stressors, LDs are involved in energy production, in the synthesis of membranes and signaling molecules, and in the protection of cells against lipotoxicity and free radicals. Accumulation of LDs in the CNS appears predominantly in neuroglia (astrocytes, microglia, oligodendrocytes, ependymal cells), which provide trophic, metabolic, and immune support to neuronal networks. Here we review the most recent findings on the characteristics and functions of LDs in neuroglia, focusing on astrocytes, the key homeostasis-providing cells in the CNS. We discuss the molecular mechanisms affecting LD turnover in neuroglia under stress and how this may protect neural cell function. We also highlight the role (and potential contribution) of neuroglial LDs in aging and in neurologic disorders.
Collapse
|
11
|
Daemen S, van Polanen N, Bilet L, Phielix E, Moonen-Kornips E, Schrauwen-Hinderling VB, Schrauwen P, Hesselink MKC. Postexercise changes in myocellular lipid droplet characteristics of young lean individuals are affected by circulatory nonesterified fatty acids. Am J Physiol Endocrinol Metab 2021; 321:E453-E463. [PMID: 34396784 DOI: 10.1152/ajpendo.00654.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intramyocellular lipid (IMCL) content is an energy source during acute exercise. Nonesterified fatty acid (NEFA) levels can compete with IMCL utilization during exercise. IMCL content is stored as lipid droplets (LDs) that vary in size, number, subcellular distribution, and in coating with LD protein PLIN5. Little is known about how these factors are affected during exercise and recovery. Here, we aimed to investigate the effects of acute exercise with and without elevated NEFA levels on intramyocellular LD size and number, intracellular distribution and PLIN5 coating, using high-resolution confocal microscopy. In a crossover study, 9 healthy lean young men performed a 2-h moderate intensity cycling protocol in the fasted (high NEFA levels) and glucose-fed state (low NEFA levels). IMCL and LD parameters were measured at baseline, directly after exercise and 4 h postexercise. We found that total IMCL content was not changed directly after exercise (irrespectively of condition), but IMCL increased 4 h postexercise in the fasting condition, which was due to an increased number of LDs rather than changes in size. The effects were predominantly detected in type I muscle fibers and in LDs coated with PLIN5. Interestingly, subsarcolemmal, but not intermyofibrillar IMCL content, was decreased directly after exercise in the fasting condition and was replenished during the 4 h recovery period. In conclusion, acute exercise affects IMCL storage during exercise and recovery, particularly in type I muscle fibers, in the subsarcolemmal region and in the presence of PLIN5. Moreover, the effects of exercise on IMCL content are affected by plasma NEFA levels.NEW & NOTEWORTHY Skeletal muscle stores lipids in lipid droplets (LDs) that can vary in size, number, and location and are a source of energy during exercise. Specifically, subsarcolemmal LDs were used during exercise when fasted. Exercising in the fasted state leads to postrecovery elevation in IMCL levels due to an increase in LD number in type I muscle fibers, in subsarcolemmal region and decorated with PLIN5. These effects are blunted by glucose ingestion during exercise and recovery.
Collapse
Affiliation(s)
- Sabine Daemen
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Nynke van Polanen
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Lena Bilet
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Esther Phielix
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Esther Moonen-Kornips
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Vera B Schrauwen-Hinderling
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
- Department of Radiology, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Patrick Schrauwen
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Matthijs K C Hesselink
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| |
Collapse
|
12
|
Mitochondrial Functionality in Inflammatory Pathology-Modulatory Role of Physical Activity. Life (Basel) 2021; 11:life11010061. [PMID: 33467642 PMCID: PMC7831038 DOI: 10.3390/life11010061] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/14/2022] Open
Abstract
The incidence and severity of metabolic diseases can be reduced by introducing healthy lifestyle habits including moderate exercise. A common observation in age-related metabolic diseases is an increment in systemic inflammation (the so-called inflammaging) where mitochondrial reactive oxygen species (ROS) production may have a key role. Exercise prevents these metabolic pathologies, at least in part, due to its ability to alter immunometabolism, e.g., reducing systemic inflammation and by improving immune cell metabolism. Here, we review how exercise regulates immunometabolism within contracting muscles. In fact, we discuss how circulating and resident macrophages alter their function due to mitochondrial signaling, and we propose how these effects can be triggered within skeletal muscle in response to exercise. Finally, we also describe how exercise-induced mitochondrial adaptations can help to fight against virus infection. Moreover, the fact that moderate exercise increases circulating immune cells must be taken into account by public health agencies, as it may help prevent virus spread. This is of interest in order to face not only acute respiratory-related coronavirus (SARS-CoV) responsible for the COVID-19 pandemic but also for future virus infection challenges.
Collapse
|
13
|
Seibert JT, Najt CP, Heden TD, Mashek DG, Chow LS. Muscle Lipid Droplets: Cellular Signaling to Exercise Physiology and Beyond. Trends Endocrinol Metab 2020; 31:928-938. [PMID: 32917515 PMCID: PMC7704552 DOI: 10.1016/j.tem.2020.08.002] [Citation(s) in RCA: 1] [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: 04/01/2020] [Revised: 07/09/2020] [Accepted: 08/13/2020] [Indexed: 12/21/2022]
Abstract
Conventionally viewed as energy storage depots, lipid droplets (LDs) play a central role in muscle lipid metabolism and intracellular signaling, as recognized by recent advances in our biological understanding. Specific subpopulations of muscle LDs, defined by location and associated proteins, are responsible for distinct biological functions. In this review, the traditional view of muscle LDs is examined, and the emerging role of LDs in intracellular signaling is highlighted. The effects of chronic and acute exercise on muscle LD metabolism and signaling is discussed. In conclusion, future directions for muscle LD research are identified. The primary focus will be on human studies, with inclusion of select animal/cellular/non-muscle studies as appropriate, to provide the underlying mechanisms driving the observed findings.
Collapse
Affiliation(s)
- Jacob T Seibert
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Charles P Najt
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Timothy D Heden
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA
| | - Lisa S Chow
- Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA.
| |
Collapse
|
14
|
Gemmink A, Schrauwen P, Hesselink MKC. Exercising your fat (metabolism) into shape: a muscle-centred view. Diabetologia 2020; 63:1453-1463. [PMID: 32529413 PMCID: PMC7351830 DOI: 10.1007/s00125-020-05170-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/23/2020] [Indexed: 12/11/2022]
Abstract
Fatty acids are an important energy source during exercise. Training status and substrate availability are determinants of the relative and absolute contribution of fatty acids and glucose to total energy expenditure. Endurance-trained athletes have a high oxidative capacity, while, in insulin-resistant individuals, fat oxidation is compromised. Fatty acids that are oxidised during exercise originate from the circulation (white adipose tissue lipolysis), as well as from lipolysis of intramyocellular lipid droplets. Moreover, hepatic fat may contribute to fat oxidation during exercise. Nowadays, it is clear that myocellular lipid droplets are dynamic organelles and that number, size, subcellular distribution, lipid droplet coat proteins and mitochondrial tethering of lipid droplets are determinants of fat oxidation during exercise. This review summarises recent insights into exercise-mediated changes in lipid metabolism and insulin sensitivity in relation to lipid droplet characteristics in human liver and muscle. Graphical abstract.
Collapse
Affiliation(s)
- Anne Gemmink
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, 6200 MD, Maastricht, the Netherlands
| | - Patrick Schrauwen
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, 6200 MD, Maastricht, the Netherlands
| | - Matthijs K C Hesselink
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, 6200 MD, Maastricht, the Netherlands.
| |
Collapse
|
15
|
Strauss JA, Shepherd DA, Macey M, Jevons EFP, Shepherd SO. Divergence exists in the subcellular distribution of intramuscular triglyceride in human skeletal muscle dependent on the choice of lipid dye. Histochem Cell Biol 2020; 154:369-382. [PMID: 32627050 PMCID: PMC7532971 DOI: 10.1007/s00418-020-01898-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2020] [Indexed: 01/19/2023]
Abstract
Despite over 50 years of research, a comprehensive understanding of how intramuscular triglyceride (IMTG) is stored in skeletal muscle and its contribution as a fuel during exercise is lacking. Immunohistochemical techniques provide information on IMTG content and lipid droplet (LD) morphology on a fibre type and subcellular-specific basis, and the lipid dye Oil Red O (ORO) is commonly used to achieve this. BODIPY 493/503 (BODIPY) is an alternative lipid dye with lower background staining and narrower emission spectra. Here we provide the first quantitative comparison of BODIPY and ORO for investigating exercise-induced changes in IMTG content and LD morphology on a fibre type and subcellular-specific basis. Estimates of IMTG content were greater when using BODIPY, which was predominantly due to BODIPY detecting a larger number of LDs, compared to ORO. The subcellular distribution of intramuscular lipid was also dependent on the lipid dye used; ORO detects a greater proportion of IMTG in the periphery (5 μm below cell membrane) of the fibre, whereas IMTG content was higher in the central region using BODIPY. In response to 60 min moderate-intensity cycling exercise, IMTG content was reduced in both the peripheral (− 24%) and central region (− 29%) of type I fibres (P < 0.05) using BODIPY, whereas using ORO, IMTG content was only reduced in the peripheral region of type I fibres (− 31%; P < 0.05). As well as highlighting some methodological considerations herein, our investigation demonstrates that important differences exist between BODIPY and ORO for detecting and quantifying IMTG on a fibre type and subcellular-specific basis.
Collapse
Affiliation(s)
- Juliette A Strauss
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, L3 3AF, UK.
| | - Daisy A Shepherd
- Clinical Epidemiology and Biostatistics Unit, Murdoch Children's Research Institute, Royal Children's Hospital, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, Victoria, 3010, Australia
| | - Myfanwy Macey
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Emily F P Jevons
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Sam O Shepherd
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
| |
Collapse
|
16
|
Jevons EFP, Gejl KD, Strauss JA, Ørtenblad N, Shepherd SO. Skeletal muscle lipid droplets are resynthesized before being coated with perilipin proteins following prolonged exercise in elite male triathletes. Am J Physiol Endocrinol Metab 2020; 318:E357-E370. [PMID: 31935113 DOI: 10.1152/ajpendo.00399.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Intramuscular triglycerides (IMTG) are a key substrate during prolonged exercise, but little is known about the rate of IMTG resynthesis in the postexercise period. We investigated the hypothesis that the distribution of the lipid droplet (LD)-associated perilipin (PLIN) proteins is linked to IMTG storage following exercise. Fourteen elite male triathletes (27 ± 1 yr, 66.5 ± 1.3 mL·kg-1·min-1) completed 4 h of moderate-intensity cycling. During the first 4 h of recovery, subjects received either carbohydrate or H2O, after which both groups received carbohydrate. Muscle biopsies collected pre- and postexercise and 4 and 24 h postexercise were analyzed using confocal immunofluorescence microscopy for fiber type-specific IMTG content and PLIN distribution with LDs. Exercise reduced IMTG content in type I fibers (-53%, P = 0.002), with no change in type IIa fibers. During the first 4 h of recovery, IMTG content increased in type I fibers (P = 0.014), but was not increased more after 24 h, where it was similar to baseline levels in both conditions. During recovery the number of LDs labeled with PLIN2 (70%), PLIN3 (63%), and PLIN5 (62%; all P < 0.05) all increased in type I fibers. Importantly, the increase in LDs labeled with PLIN proteins only occurred at 24 h postexercise. In conclusion, IMTG resynthesis occurs rapidly in type I fibers following prolonged exercise in highly trained individuals. Furthermore, increases in IMTG content following exercise preceded an increase in the number of LDs labeled with PLIN proteins. These data, therefore, suggest that the PLIN proteins do not play a key role in postexercise IMTG resynthesis.
Collapse
Affiliation(s)
- Emily F P Jevons
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Kasper D Gejl
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Juliette A Strauss
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Sam O Shepherd
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| |
Collapse
|
17
|
Abstract
Lipid droplets (LDs) are fat storage organelles integral to energy homeostasis and a wide range of cellular processes. LDs physically and functionally interact with many partner organelles, including the ER, mitochondria, lysosomes, and peroxisomes. Recent findings suggest that the dynamics of LD inter-organelle contacts is in part controlled by LD intracellular motility. LDs can be transported directly by motor proteins along either actin filaments or microtubules, via Kinesin-1, Cytoplasmic Dynein, and type V Myosins. LDs can also be propelled indirectly, by hitchhiking on other organelles, cytoplasmic flows, and potentially actin polymerization. Although the anchors that attach motors to LDs remain elusive, other regulators of LD motility have been identified, ranging from modification of the tracks to motor co-factors to members of the perilipin family of LD proteins. Manipulating these regulatory pathways provides a tool to probe whether altered motility affects organelle contacts and has revealed that LD motility can promote interactions with numerous partners, with profound consequences for metabolism. LD motility can cause dramatic redistribution of LDs between a clustered and a dispersed state, resulting in altered organelle contacts and LD turnover. We propose that LD motility can thus promote switches in the metabolic state of a cell. Finally, LD motility is also important for LD allocation during cell division. In a number of animal embryos, uneven allocation results in a large difference in LD content in distinct daughter cells, suggesting cell-type specific LD needs.
Collapse
Affiliation(s)
- Marcus D Kilwein
- Department of Biology, University of Rochester, RC Box 270211, Rochester, NY 14627, USA
| | - M A Welte
- Department of Biology, University of Rochester, RC Box 270211, Rochester, NY 14627, USA
| |
Collapse
|
18
|
Hansen MT, Rømer T, Frandsen J, Larsen S, Dela F, Helge JW. Determination and validation of peak fat oxidation in endurance-trained men using an upper body graded exercise test. Scand J Med Sci Sports 2019; 29:1677-1690. [PMID: 31309617 DOI: 10.1111/sms.13519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/26/2019] [Accepted: 07/02/2019] [Indexed: 12/13/2022]
Abstract
Peak fat oxidation rate (PFO) and the intensity that elicits PFO (Fatmax ) are commonly determined by a validated graded exercise test (GE) on a cycling ergometer with indirect calorimetry. However, for upper body exercise fat oxidation rates are not well elucidated and no protocol has been validated. Thus, our aim was to test validity and inter-method reliability for determination of PFO and Fatmax in trained men using a GE protocol applying double poling on a ski-ergometer. PFO and Fatmax were assessed during two identical GE tests (GE1 and GE2) and validated against separated short continuous exercise bouts (SCE) at 35%, 50%, and 65% of V̇O2peak on the ski-ergometer in 10 endurance-trained men (V̇O2peak : 65.1 ± 1.0 mL·min-1 ·kg-1 , mean ± SEM). Between GE tests no differences were found in PFO (GE1: 0.42 ± 0.03; GE2: 0.45 ± 0.03 g·min-1 , P = .256) or Fatmax (GE1: 41 ± 2%; GE2: 43 ± 3% of V̇O2peak , P = .457) and the intra-individual coefficient of variation (CV) was 8 ± 2% and 11 ± 2% for PFO and Fatmax , respectively. Between GE and SCE tests, PFO (GEavg : 0.44 ± 0.03; SCE; 0.47 ± 0.06 g·min-1 , P = .510) was not different, whereas a difference in Fatmax (GEavg : 42 ± 2%; SCE: 52 ± 4% of V̇O2peak , P = .030) was observed with a CV of 17 ± 4% and 15 ± 4% for PFO and Fatmax , respectively. In conclusion, GE has a high day-to-day reliability in determination of PFO and Fatmax in trained men, whereas it is unclear if PFO and Fatmax determined by GE reflect continuous exercise in general.
Collapse
Affiliation(s)
- Mikkel Thunestvedt Hansen
- Xlab, Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark
| | - Tue Rømer
- Xlab, Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark
| | - Jacob Frandsen
- Xlab, Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark
| | - Steen Larsen
- Xlab, Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark.,Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
| | - Flemming Dela
- Xlab, Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark.,Department of Geriatrics, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Jørn Wulff Helge
- Xlab, Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
19
|
Skeletal Muscle Lipid Droplets and the Athlete's Paradox. Cells 2019; 8:cells8030249. [PMID: 30875966 PMCID: PMC6468652 DOI: 10.3390/cells8030249] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/07/2019] [Accepted: 03/12/2019] [Indexed: 12/17/2022] Open
Abstract
The lipid droplet (LD) is an organelle enveloped by a monolayer phospholipid membrane with a core of neutral lipids, which is conserved from bacteria to humans. The available evidence suggests that the LD is essential to maintaining lipid homeostasis in almost all organisms. As a consequence, LDs also play an important role in pathological metabolic processes involving the ectopic storage of neutral lipids, including type 2 diabetes mellitus (T2DM), atherosclerosis, steatosis, and obesity. The degree of insulin resistance in T2DM patients is positively correlated with the size of skeletal muscle LDs. Aerobic exercise can reduce the occurrence and development of various metabolic diseases. However, trained athletes accumulate lipids in their skeletal muscle, and LD size in their muscle tissue is positively correlated with insulin sensitivity. This phenomenon is called the athlete’s paradox. This review will summarize previous studies on the relationship between LDs in skeletal muscle and metabolic diseases and will discuss the paradox at the level of LDs.
Collapse
|
20
|
Koh HCE, Ørtenblad N, Winding KM, Hellsten Y, Mortensen SP, Nielsen J. High-intensity interval, but not endurance, training induces muscle fiber type-specific subsarcolemmal lipid droplet size reduction in type 2 diabetic patients. Am J Physiol Endocrinol Metab 2018; 315:E872-E884. [PMID: 30016151 DOI: 10.1152/ajpendo.00161.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This study compared the effects of moderate-intensity endurance training and high-intensity interval training on fiber type-specific subcellular volumetric content and morphology of lipid droplets and mitochondria in skeletal muscles of type 2 diabetic patients. Sixteen sedentary type 2 diabetic patients (57 ± 7 yr old) were randomized to complete 11 wk of either 40-min cycling at 50% peak workload (Endurance, n = 8) or 10 1-min cycling intervals at 95% peak workload separated by 1 min of recovery (High-Intensity Interval, n = 8), three times per week. Assessments for cardiorespiratory fitness, body composition, glycemic control, together with muscle biopsies were performed before and after the intervention. Morphometric analyses of lipid droplets and mitochondria were conducted in the subcellular fractions of biopsied muscle fibers using quantitative electron microscopy. The training intervention increased cardiorespiratory fitness, lowered fat mass, and improved nonfasting glycemic control ( P < 0.05), with no difference between training modalities. In the subsarcolemmal space, training decreased lipid droplet volume ( P = 0.003), and high-intensity interval, but not endurance, training reduced the size of lipid droplets, specifically in type 2 fibers ( P < 0.001). No training-induced change in intermyofibrillar lipid droplets was observed in both fiber types. Subsarcolemmal mitochondrial volume was increased by high-intensity interval ( P = 0.02), but not endurance, training ( P = 0.79). Along with improvement in glycemic control, low-volume high-intensity interval training is an alternative time-saving training modality that affects subcellular morphology and volumetric content of lipid droplets in skeletal muscle of type 2 diabetic patients.
Collapse
Affiliation(s)
- Han-Chow E Koh
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark , Odense , Denmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark , Odense , Denmark
| | - Kamilla M Winding
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen , Copenhagen , Denmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen , Copenhagen , Denmark
| | - Stefan P Mortensen
- Department of Cardiovascular and Renal Research, Faculty of Health Sciences, University of Southern Denmark , Odense , Denmark
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen , Copenhagen , Denmark
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark , Odense , Denmark
| |
Collapse
|
21
|
Ørtenblad N, Nielsen J, Boushel R, Söderlund K, Saltin B, Holmberg HC. The Muscle Fiber Profiles, Mitochondrial Content, and Enzyme Activities of the Exceptionally Well-Trained Arm and Leg Muscles of Elite Cross-Country Skiers. Front Physiol 2018; 9:1031. [PMID: 30116201 PMCID: PMC6084043 DOI: 10.3389/fphys.2018.01031] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 07/11/2018] [Indexed: 01/11/2023] Open
Abstract
As one of the most physically demanding sports in the Olympic Games, cross-country skiing poses considerable challenges with respect to both force generation and endurance during the combined upper- and lower-body effort of varying intensity and duration. The isoforms of myosin in skeletal muscle have long been considered not only to define the contractile properties, but also to determine metabolic capacities. The current investigation was designed to explore the relationship between these isoforms and metabolic profiles in the arms (triceps brachii) and legs (vastus lateralis) as well as the range of training responses in the muscle fibers of elite cross-country skiers with equally and exceptionally well-trained upper and lower bodies. The proportion of myosin heavy chain (MHC)-1 was higher in the leg (58 ± 2% [34-69%]) than arm (40 ± 3% [24-57%]), although the mitochondrial volume percentages [8.6 ± 1.6 (leg) and 9.0 ± 2.0 (arm)], and average number of capillaries per fiber [5.8 ± 0.8 (leg) and 6.3 ± 0.3 (arm)] were the same. In these comparable highly trained leg and arm muscles, the maximal citrate synthase (CS) activity was the same. Still, 3-hydroxy-acyl-CoA-dehydrogenase (HAD) capacity was 52% higher (P < 0.05) in the leg compared to arm muscles, suggesting a relatively higher capacity for lipid oxidation in leg muscle, which cannot be explained by the different fiber type distributions. For both limbs combined, HAD activity was correlated with the content of MHC-1 (r2 = 0.32, P = 0.011), whereas CS activity was not. Thus, in these highly trained cross-country skiers capillarization of and mitochondrial volume in type 2 fiber can be at least as high as in type 1 fibers, indicating a divergence between fiber type pattern and aerobic metabolic capacity. The considerable variability in oxidative metabolism with similar MHC profiles provides a new perspective on exercise training. Furthermore, the clear differences between equally well-trained arm and leg muscles regarding HAD activity cannot be explained by training status or MHC distribution, thereby indicating an intrinsic metabolic difference between the upper and lower body. Moreover, trained type 1 and type 2A muscle fibers exhibited similar aerobic capacity regardless of whether they were located in an arm or leg muscle.
Collapse
Affiliation(s)
- Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster, University of Southern Denmark, Odense, Denmark.,School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster, University of Southern Denmark, Odense, Denmark
| | - Robert Boushel
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Karin Söderlund
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Bengt Saltin
- Copenhagen Muscle Research Centre, Copenhagen, Denmark
| | - Hans-Christer Holmberg
- Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden.,School of Sport Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| |
Collapse
|
22
|
Loiselle DS, Barclay CJ. The ineluctable constraints of thermodynamics in the aetiology of obesity. Clin Exp Pharmacol Physiol 2017; 45:219-225. [PMID: 28994136 DOI: 10.1111/1440-1681.12869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/23/2017] [Accepted: 09/25/2017] [Indexed: 11/30/2022]
Abstract
We exploit the detail-independence feature of thermodynamics to examine issues related to the development of obesity. We adopt a 'global' approach consistent with focus on the first law of thermodynamics - namely that the metabolic energy provided by dietary foodstuffs has only three possible fates: the performance of work (be it microscopic or macroscopic), the generation of heat, or storage - primarily in the form of adipose tissue. Quantification of the energy expended, in the form of fat metabolised, during selected endurance events, reveals the inherent limitation of over-reliance on exercise as a primary agent of weight loss. This result prompts examination of various (non-exercise based) possibilities of increasing the rate of heat loss. Since these, too, give little cause for optimism, we are obliged to conclude that obesity can be prevented, or weight loss achieved, only if exercise is supplemented by reduction of food intake.
Collapse
Affiliation(s)
- Denis S Loiselle
- Department of Physiology, The University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Christopher J Barclay
- Auckland Bioengineering Institute (Honorary membership), The University of Auckland, Auckland, New Zealand
| |
Collapse
|
23
|
Whytock KL, Jevons EFP, Strauss JA, Shepherd SO. Under the microscope: insights into limb-specific lipid droplet metabolism. J Physiol 2017; 595:6229-6230. [PMID: 28791715 DOI: 10.1113/jp275014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- K L Whytock
- Research Institute for Sport & Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - E F P Jevons
- Research Institute for Sport & Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - J A Strauss
- Research Institute for Sport & Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - S O Shepherd
- Research Institute for Sport & Exercise Science, Liverpool John Moores University, Liverpool, UK
| |
Collapse
|