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Florez CM, Prather J, Miller D, Vargas A, Soto B, Harrison A, Tinsley G, Taylor L. The Effects of Two Servings of a Thermogenic Supplement on Metabolism, Hemodynamic Variables, and Mood State Outcomes in Young Overweight Adults. Cureus 2024; 16:e54484. [PMID: 38516475 PMCID: PMC10954375 DOI: 10.7759/cureus.54484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2024] [Indexed: 03/23/2024] Open
Abstract
Introduction We examined if acute ingestion of a novel thermogenic supplement influences resting energy expenditure (REE), mood, and hemodynamic function. Methods Forty-six adults completed this randomized, placebo-controlled, double-blind, crossover study. Participants underwent two conditions: placebo (PL) and treatment (TX) containing 300 mg of caffeine and 3 g of acetyl-L-carnitine. REE, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and mood states were assessed at baseline and 30, 60, and 120 minutes post-ingestion. Data were analyzed using repeated measures analysis of variance. Results A significant condition-by-time interaction was observed for REE. At the 30-, 60-, and 120-minute post-ingestion timepoints, REE was 202 ± 26, 238 ± 40, and 209 ± 29 kcal/d greater in the TX condition compared to PL. No significant differences were observed for SBP and HR but a significant interaction indicated that DBP was elevated at 30 minutes in the TX vs. PL, though values remained within normal ranges. Significant interactions were observed for perceived alertness, concentration, energy, and focus, with increases in TX. Conclusion These data provide evidence that acute consumption of the thermogenic dietary supplement OxyShred (EHPlabs, Salt Lake City, Utah, USA) stimulates increases in REE that are sustained for ≥ two hours, along with increasing perceived alertness, concentration, energy, and focus. Changes in hemodynamic function are minimal and within normal ranges.
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Affiliation(s)
| | - Jessica Prather
- Human Performance Lab, University of Mary Hardin-Baylor, Belton, USA
| | - Dylon Miller
- Human Performance Lab, University of Mary Hardin-Baylor, Belton, USA
| | - Amie Vargas
- Human Performance Lab, University of Mary Hardin-Baylor, Belton, USA
| | - Bella Soto
- Human Performance Lab, University of Mary Hardin-Baylor, Belton, USA
| | - Abby Harrison
- Human Performance Lab, University of Mary Hardin-Baylor, Belton, USA
| | - Grant Tinsley
- Kinesiology & Sport Management, Texas Tech University, Lubbock, USA
| | - Lem Taylor
- Physiology and Nutrition, University of Mary Hardin-Baylor, Belton, USA
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2
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Shannon CE, Ní Chathail MB, Mullin SM, Meehan A, McGillicuddy FC, Roche HM. Precision nutrition for targeting pathophysiology of cardiometabolic phenotypes. Rev Endocr Metab Disord 2023; 24:921-936. [PMID: 37402955 PMCID: PMC10492734 DOI: 10.1007/s11154-023-09821-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/22/2023] [Indexed: 07/06/2023]
Abstract
Obesity is a heterogenous disease accompanied by a broad spectrum of cardiometabolic risk profiles. Traditional paradigms for dietary weight management do not address biological heterogeneity between individuals and have catastrophically failed to combat the global pandemic of obesity-related diseases. Nutritional strategies that extend beyond basic weight management to instead target patient-specific pathophysiology are warranted. In this narrative review, we provide an overview of the tissue-level pathophysiological processes that drive patient heterogeneity to shape distinct cardiometabolic phenotypes in obesity. Specifically, we discuss how divergent physiology and postprandial phenotypes can reveal key metabolic defects within adipose, liver, or skeletal muscle, as well as the integrative involvement of the gut microbiome and the innate immune system. Finally, we highlight potential precision nutritional approaches to target these pathways and discuss recent translational evidence concerning the efficacy of such tailored dietary interventions for different obesity phenotypes, to optimise cardiometabolic benefits.
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Affiliation(s)
- Christopher E Shannon
- Nutrigenomics Research Group, UCD Conway Institute, and Institute of Food and Health, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Republic of Ireland
- School of Medicine, University College Dublin, Dublin, Republic of Ireland
- Division of Diabetes, Department of Medicine, UT Health San Antonio, San Antonio, TX, USA
| | - Méabh B Ní Chathail
- Nutrigenomics Research Group, UCD Conway Institute, and Institute of Food and Health, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Republic of Ireland
| | - Sinéad M Mullin
- Nutrigenomics Research Group, UCD Conway Institute, and Institute of Food and Health, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Republic of Ireland
| | - Andrew Meehan
- School of Medicine, University College Dublin, Dublin, Republic of Ireland
| | | | - Helen M Roche
- Nutrigenomics Research Group, UCD Conway Institute, and Institute of Food and Health, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Republic of Ireland.
- Institute for Global Food Security, Queen's University Belfast, Belfast, Northern Ireland.
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3
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West S, Monteyne AJ, van der Heijden I, Stephens FB, Wall BT. Nutritional Considerations for the Vegan Athlete. Adv Nutr 2023; 14:774-795. [PMID: 37127187 PMCID: PMC10334161 DOI: 10.1016/j.advnut.2023.04.012] [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: 02/22/2023] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/03/2023] Open
Abstract
Accepting a continued rise in the prevalence of vegan-type diets in the general population is also likely to occur in athletic populations, it is of importance to assess the potential impact on athletic performance, adaptation, and recovery. Nutritional consideration for the athlete requires optimization of energy, macronutrient, and micronutrient intakes, and potentially the judicious selection of dietary supplements, all specified to meet the individual athlete's training and performance goals. The purpose of this review is to assess whether adopting a vegan diet is likely to impinge on such optimal nutrition and, where so, consider evidence based yet practical and pragmatic nutritional recommendations. Current evidence does not support that a vegan-type diet will enhance performance, adaptation, or recovery in athletes, but equally suggests that an athlete can follow a (more) vegan diet without detriment. A clear caveat, however, is that vegan diets consumed spontaneously may induce suboptimal intakes of key nutrients, most notably quantity and/or quality of dietary protein and specific micronutrients (eg, iron, calcium, vitamin B12, and vitamin D). As such, optimal vegan sports nutrition requires (more) careful consideration, evaluation, and planning. Individual/seasonal goals, training modalities, athlete type, and sensory/cultural/ethical preferences, among other factors, should all be considered when planning and adopting a vegan diet.
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Affiliation(s)
- Sam West
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Alistair J Monteyne
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Ino van der Heijden
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Francis B Stephens
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Benjamin T Wall
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom.
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4
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Wall BT, Machin D, Dunlop MV, Stephens FB. Caffeine ingestion stimulates plasma carnitine clearance in humans. Physiol Rep 2023; 11:e15615. [PMID: 36806708 PMCID: PMC9938004 DOI: 10.14814/phy2.15615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/20/2023] Open
Abstract
Increasing skeletal muscle carnitine content can manipulate fuel metabolism and improve exercise performance. Intravenous insulin infusion during hypercarnitinemia increases plasma carnitine clearance and Na+ -dependent muscle carnitine accretion, likely via stimulating Na+ /K+ ATPase pump activity. We hypothesized that the ingestion of high-dose caffeine, also known to stimulate Na+ /K+ ATPase activity, would stimulate plasma carnitine clearance during hypercarnitinemia in humans. In a randomized placebo-controlled study, six healthy young adults (aged 24 ± 5 years, height 175 ± 8 cm, and weight 70 ± 13 kg) underwent three 5-h laboratory visits involving the primed continuous intravenous infusion of l-carnitine (CARN and CARN + CAFF) or saline (CAFF) in parallel with ingestion of caffeine (CARN + CAFF and CAFF) or placebo (CARN) at 0, 2, 3, and 4 h. Regular blood samples were collected to determine concentrations of blood Na+ and K+ , and plasma carnitine and caffeine, concentrations. Caffeine ingestion (i.e., CAFF and CARN + CAFF conditions) and l-carnitine infusion (i.e., CARN and CARN + CAFF) elevated steady-state plasma caffeine (to ~7 μg·mL-1 ) and carnitine (to ~400 μmol·L-1 ) concentrations, respectively, throughout the 5 h infusions. Plasma carnitine concentration was ~15% lower in CARN + CAFF compared with CARN during the final 90 min of the infusion (at 210 min, 356 ± 96 vs. 412 ± 94 μmol·L-1 ; p = 0.0080: at 240 min, 350 ± 91 vs. 406 ± 102 μmol·L-1 ; p = 0.0079: and at 300 min, 357 ± 91 vs. 413 ± 110 μmol·L-1 ; p = 0.0073, respectively). Blood Na+ concentrations were greater in CAFF and CARN + CAFF compared with CARN. Ingestion of high-dose caffeine stimulates plasma carnitine clearance during hypercarnitinemia, likely via increased Na+ /K+ ATPase activity. Carnitine co-ingestion with caffeine may represent a novel muscle carnitine loading strategy in humans, and therefore manipulate skeletal muscle fuel metabolism and improve exercise performance.
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Affiliation(s)
- Benjamin T. Wall
- Department of Public Health and Sport SciencesUniversity of ExeterExeterUK
| | - David Machin
- Department of Public Health and Sport SciencesUniversity of ExeterExeterUK
| | - Mandy V. Dunlop
- Department of Public Health and Sport SciencesUniversity of ExeterExeterUK
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5
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Shur NF, Simpson EJ, Crossland H, Chivaka PK, Constantin D, Cordon SM, Constantin-Teodosiu D, Stephens FB, Lobo DN, Szewczyk N, Narici M, Prats C, Macdonald IA, Greenhaff PL. Human adaptation to immobilization: Novel insights of impacts on glucose disposal and fuel utilization. J Cachexia Sarcopenia Muscle 2022; 13:2999-3013. [PMID: 36058634 PMCID: PMC9745545 DOI: 10.1002/jcsm.13075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 06/21/2022] [Accepted: 08/14/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Bed rest (BR) reduces whole-body insulin-stimulated glucose disposal (GD) and alters muscle fuel metabolism, but little is known about metabolic adaptation from acute to chronic BR nor the mechanisms involved, particularly when volunteers are maintained in energy balance. METHODS Healthy males (n = 10, 24.0 ± 1.3 years), maintained in energy balance, underwent 3-day BR (acute BR). A second cohort matched for sex and body mass index (n = 20, 34.2 ± 1.8 years) underwent 56-day BR (chronic BR). A hyperinsulinaemic euglycaemic clamp (60 mU/m2 /min) was performed to determine rates of whole-body insulin-stimulated GD before and after BR (normalized to lean body mass). Indirect calorimetry was performed before and during steady state of each clamp to calculate rates of whole-body fuel oxidation. Muscle biopsies were taken to determine muscle glycogen, metabolite and intramyocellular lipid (IMCL) contents, and the expression of 191 mRNA targets before and after BR. Two-way repeated measures analysis of variance was used to detect differences in endpoint measures. RESULTS Acute BR reduced insulin-mediated GD (Pre 11.5 ± 0.7 vs. Post 9.3 ± 0.6 mg/kg/min, P < 0.001), which was unchanged in magnitude following chronic BR (Pre 10.2 ± 0.4 vs. Post 7.9 ± 0.3 mg/kg/min, P < 0.05). This reduction in GD was paralleled by the elimination of the 35% increase in insulin-stimulated muscle glycogen storage following both acute and chronic BR. Acute BR had no impact on insulin-stimulated carbohydrate (CHO; Pre 3.69 ± 0.39 vs. Post 4.34 ± 0.22 mg/kg/min) and lipid (Pre 1.13 ± 0.14 vs. Post 0.59 ± 0.11 mg/kg/min) oxidation, but chronic BR reduced CHO oxidation (Pre 3.34 ± 0.18 vs. Post 2.72 ± 0.13 mg/kg/min, P < 0.05) and blunted the magnitude of insulin-mediated inhibition of lipid oxidation (Pre 0.60 ± 0.07 vs. Post 0.85 ± 0.06 mg/kg/min, P < 0.05). Neither acute nor chronic BR increased muscle IMCL content. Plentiful mRNA abundance changes were detected following acute BR, which waned following chronic BR and reflected changes in fuel oxidation and muscle glycogen storage at this time point. CONCLUSIONS Acute BR suppressed insulin-stimulated GD and storage, but the extent of this suppression increased no further in chronic BR. However, insulin-mediated inhibition of fat oxidation after chronic BR was less than acute BR and was accompanied by blunted CHO oxidation. The juxtaposition of these responses shows that the regulation of GD and storage can be dissociated from substrate oxidation. Additionally, the shift in substrate oxidation after chronic BR was not explained by IMCL accumulation but reflected by muscle mRNA and pyruvate dehydrogenase kinase 4 protein abundance changes, pointing to lack of muscle contraction per se as the primary signal for muscle adaptation.
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Affiliation(s)
- Natalie F Shur
- Centre for Sport, Exercise and Osteoarthritis Research Versus Arthritis, School of Life Sciences, The University of Nottingham, Nottingham, UK.,National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK
| | - Elizabeth J Simpson
- National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK.,MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK
| | - Hannah Crossland
- National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK.,MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK
| | - Prince K Chivaka
- Centre for Sport, Exercise and Osteoarthritis Research Versus Arthritis, School of Life Sciences, The University of Nottingham, Nottingham, UK
| | - Despina Constantin
- National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK.,MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK
| | - Sally M Cordon
- MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK
| | - Dumitru Constantin-Teodosiu
- MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK
| | | | - Dileep N Lobo
- National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK.,MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK
| | - Nate Szewczyk
- National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK.,MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK.,Ohio Musculoskeletal and Neurological Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Marco Narici
- MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Clara Prats
- Core Facility for Integrated Microscopy, The University of Copenhagen, Copenhagen, Denmark
| | - Ian A Macdonald
- National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK.,MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK
| | - Paul L Greenhaff
- Centre for Sport, Exercise and Osteoarthritis Research Versus Arthritis, School of Life Sciences, The University of Nottingham, Nottingham, UK.,National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK.,MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, UK
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6
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The Association of Serum L-Carnitine Concentrations with the Risk of Cancer in Chinese Adults with Hypertension. Nutrients 2022; 14:nu14234999. [PMID: 36501029 PMCID: PMC9738465 DOI: 10.3390/nu14234999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/20/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND The effect of serum L-carnitine (LC) concentrations on cancer risk remains unclear. This study aims to explore the association between serum LC and the risk of incident cancer. METHODS This is a case-control study, including 574 patients with incident cancer and 574 controls matched in a 1:1 ratio by age, sex, and residence, nested within the China H-Type Hypertension Registry Study (CHHRS). Conditional logistic regression analysis was used to assess the association of serum LC and incident cancer risk. RESULTS When LC was assessed as quartiles, compared with patients with low LC (Q1), patients in the highest quartile (Q4) had a 33% (OR = 0.67, 95% CI: 0.46 to 0.99), 52% (OR = 0.48, 95% CI: 0.23 to 0.99), and 39% (OR = 0.61, 95% CI: 0.38 to 0.99) decreased risk of overall, digestive system, and non-digestive system cancer in the adjusted models, respectively. In subgroup analyses, an inverse association of LC with cancer risk was observed in individuals who were overweight (obese), who never drink, who never smoke, and who were female. In the mediation analysis, serum trimethylamine-N-oxide (TMAO) concentrations did not mediate the reversed association of LC with cancer risk. CONCLUSIONS This study showed that serum LC concentrations had a protective impact on overall, digestive system, and non-digestive system cancer risk.
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7
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Wang JX, Rahimnejad S, Zhang YY, Ren J, Wang J, Qiao F, Zhang ML, Du ZY. Mildronate triggers growth suppression and lipid accumulation in largemouth bass (Micropterus salmoides) through disturbing lipid metabolism. FISH PHYSIOLOGY AND BIOCHEMISTRY 2022; 48:145-159. [PMID: 35034221 DOI: 10.1007/s10695-021-01040-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/05/2021] [Indexed: 06/14/2023]
Abstract
Many metabolic diseases in fish are often associated with lowered mitochondrial fatty acid β-oxidation (FAO). However, the physiological role of mitochondrial FAO in lipid metabolism has not been verified in many carnivorous fish species, for example in largemouth bass (Micropterus salmonids). In the present study, a specific mitochondrial FAO inhibitor, mildronate (MD), was used to investigate the effects of impaired mitochondrial FAO on growth performance, health status, and lipid metabolism of largemouth bass. The results showed that the dietary MD treatment significantly suppressed growth performance and caused heavy lipid accumulation, especially neutral lipid, in the liver. The MD-treated fish exhibited lower monounsaturated fatty acid and higher long-chain polyunsaturated fatty acids in the muscle. The MD treatment downregulated the gene expressions in lipolysis and lipogenesis, as well as the expressions of the genes and some key proteins in FAO without enhancing peroxisomal FAO. Additionally, the MD-treated fish had lower serum aspartate aminotransferase activity and lower pro-inflammation- and apoptosis-related genes in the liver. Taken together, MD treatment markedly induced lipid accumulation via depressing lipid catabolism. Our findings reveal the pivotal roles of mitochondrial FAO in maintaining health and lipid homeostasis in largemouth bass and could be hopeful in understanding metabolic diseases in farmed carnivorous fish.
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Affiliation(s)
- Jun-Xian Wang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Samad Rahimnejad
- Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in České Budějovice, Vodňany, Czech Republic
| | - Yan-Yu Zhang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | | | - Jie Wang
- HANOVE Research Center, Wuxi, China
| | - Fang Qiao
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Mei-Ling Zhang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Zhen-Yu Du
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China.
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8
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Mielgo-Ayuso J, Pietrantonio L, Viribay A, Calleja-González J, González-Bernal J, Fernández-Lázaro D. Effect of Acute and Chronic Oral l-Carnitine Supplementation on Exercise Performance Based on the Exercise Intensity: A Systematic Review. Nutrients 2021; 13:4359. [PMID: 34959912 PMCID: PMC8704793 DOI: 10.3390/nu13124359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/28/2021] [Accepted: 12/01/2021] [Indexed: 11/16/2022] Open
Abstract
l-Carnitine (l-C) and any of its forms (glycine-propionyl l-Carnitine (GPL-C) or l-Carnitine l-tartrate (l-CLT)) has been frequently recommended as a supplement to improve sports performance due to, among others, its role in fat metabolism and in maintaining the mitochondrial acetyl-CoA/CoA ratio. The main aim of the present systematic review was to determine the effects of oral l-C supplementation on moderate- (50-79% V˙O2 max) and high-intensity (≥80% V˙O2 max) exercise performance and to show the effective doses and ideal timing of its intake. A structured search was performed according to the PRISMA® statement and the PICOS guidelines in the Web of Science (WOS) and Scopus databases, including selected data obtained up to 24 October 2021. The search included studies where l-C or glycine-propionyl l-Carnitine (GPL-C) supplementation was compared with a placebo in an identical situation and tested its effects on high and/or low-moderate performance. The trials that used the supplementation of l-C together with additional supplements were eliminated. There were no applied filters on physical fitness level, race, or age of the participants. The methodological quality of studies was evaluated by the McMaster Critical Review Form. Of the 220 articles obtained, 11 were finally included in this systematic review. Six studies used l-C, while three studies used l-CLT, and two others combined the molecule propionyl l-Carnitine (PL-C) with GPL-C. Five studies analyzed chronic supplementation (4-24 weeks) and six studies used an acute administration (<7 days). The administration doses in this chronic supplementation varied from 1 to 3 g/day; in acute supplementation, oral l-C supplementation doses ranged from 3 to 4 g. On the one hand, the effects of oral l-C supplementation on high-intensity exercise performance variables were analyzed in nine studies. Four of them measured the effects of chronic supplementation (lower rating of perceived exertion (RPE) after 30 min at 80% V˙O2 max on cycle ergometer and higher work capacity in "all-out" tests, peak power in a Wingate test, and the number of repetitions and volume lifted in leg press exercises), and five studies analyzed the effects of acute supplementation (lower RPE after graded exercise test on the treadmill until exhaustion and higher peak and average power in the Wingate cycle ergometer test). On the other hand, the effects of l-C supplementation on moderate exercise performance variables were observed in six studies. Out of those, three measured the effect of an acute supplementation, and three described the effect of a chronic supplementation, but no significant improvements on performance were found. In summary, l-C supplementation with 3 to 4 g ingested between 60 and 90 min before testing or 2 to 2.72 g/day for 9 to 24 weeks improved high-intensity exercise performance. However, chronic or acute l-C or GPL-C supplementation did not present improvements on moderate exercise performance.
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Affiliation(s)
- Juan Mielgo-Ayuso
- Department of Health Sciences, Faculty of Health Sciences, University of Burgos, 09001 Burgos, Spain;
| | - Laura Pietrantonio
- Faculty of Sport Science, Universidad Europea de Madrid, 28670 Madrid, Spain;
| | - Aitor Viribay
- Glut4Science, Physiology, Nutrition and Sport, 01004 Vitoria-Gasteiz, Spain;
| | - Julio Calleja-González
- Department of Physical Education and Sport, Faculty of Education and Sport, University of the Basque Country, 01007 Vitoria, Spain;
| | - Jerónimo González-Bernal
- Department of Health Sciences, Faculty of Health Sciences, University of Burgos, 09001 Burgos, Spain;
| | - Diego Fernández-Lázaro
- Department of Cellular Biology, Histology and Pharmacology, Faculty of Health Sciences, Campus of Soria, University of Valladolid, 42003 Soria, Spain;
- Neurobiology Research Group, Faculty of Medicine, University of Valladolid, 47005 Valladolid, Spain
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9
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Lim RMH, Koh AS. Cardiovascular Aging and Physical Activity: Insights From Metabolomics. Front Cardiovasc Med 2021; 8:728228. [PMID: 34616784 PMCID: PMC8488139 DOI: 10.3389/fcvm.2021.728228] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/26/2021] [Indexed: 12/22/2022] Open
Abstract
The purpose of this review is to explore how metabolomics can help uncover mechanisms through which physical activity may influence the progression of cardiovascular aging. Cardiovascular aging is a process of functional and structural changes in older adults which can progress to cardiovascular disease. Metabolomics profiling is an investigative tool that can track the diverse changes which occur in human biochemistry with physical activity and aging. This mini review will summarize published investigations in metabolomics and physical activity, with a specific focus on the metabolic pathways that connect physical activity with cardiovascular aging.
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Affiliation(s)
| | - Angela S Koh
- National Heart Centre Singapore, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
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10
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Chee C, Shannon CE, Burns A, Selby AL, Wilkinson D, Smith K, Greenhaff PL, Stephens FB. Increasing skeletal muscle carnitine content in older individuals increases whole-body fat oxidation during moderate-intensity exercise. Aging Cell 2021; 20:e13303. [PMID: 33464721 PMCID: PMC7884033 DOI: 10.1111/acel.13303] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/20/2020] [Accepted: 12/21/2020] [Indexed: 12/13/2022] Open
Abstract
Intramyocellular lipid (IMCL) utilization is impaired in older individuals, and IMCL accumulation is associated with insulin resistance. We hypothesized that increasing muscle total carnitine content in older men would increase fat oxidation and IMCL utilization during exercise, and improve insulin sensitivity. Fourteen healthy older men (69 ± 1 year, BMI 26.5 ± 0.8 kg/m2 ) performed 1 h of cycling at 50% VO2 max and, on a separate occasion, underwent a 60 mU/m2 /min euglycaemic hyperinsulinaemic clamp before and after 25 weeks of daily ingestion of a 220 ml insulinogenic beverage (44.4 g carbohydrate, 13.8 g protein) containing 4.5 g placebo (n = 7) or L-carnitine L-tartrate (n = 7). During supplementation, participants performed twice-weekly cycling for 1 h at 50% VO2 max. Placebo ingestion had no effect on muscle carnitine content or total fat oxidation during exercise at 50% VO2 max. L-carnitine supplementation resulted in a 20% increase in muscle total carnitine content (20.1 ± 1.2 to 23.9 ± 1.7 mmol/kg/dm; p < 0.01) and a 20% increase in total fat oxidation (181.1 ± 15.0 to 220.4 ± 19.6 J/kg lbm/min; p < 0.01), predominantly due to increased IMCL utilization. These changes were associated with increased expression of genes involved in fat metabolism (ACAT1, DGKD & PLIN2; p < 0.05). There was no change in resting insulin-stimulated whole-body or skeletal muscle glucose disposal after supplementation. This is the first study to demonstrate that a carnitine-mediated increase in fat oxidation is achievable in older individuals. This warrants further investigation given reduced lipid turnover is associated with poor metabolic health in older adults.
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Affiliation(s)
- Carolyn Chee
- MRC/Versus Arthritis Centre for Musculoskeletal Ageing ResearchSchool of Life SciencesUniversity of NottinghamNottinghamUK
| | - Chris E. Shannon
- Diabetes DivisionUniversity of Texas Health Science CentreSan AntonioTXUSA
| | - Aisling Burns
- Sam and Ann Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science CentreSan AntonioTXUSA
| | - Anna L. Selby
- MRC/Versus Arthritis Centre for Musculoskeletal Ageing ResearchSchool of MedicineUniversity of NottinghamNottinghamUK
| | - Daniel Wilkinson
- MRC/Versus Arthritis Centre for Musculoskeletal Ageing ResearchSchool of MedicineUniversity of NottinghamNottinghamUK
| | - Kenneth Smith
- MRC/Versus Arthritis Centre for Musculoskeletal Ageing ResearchSchool of MedicineUniversity of NottinghamNottinghamUK
| | - Paul L. Greenhaff
- MRC/Versus Arthritis Centre for Musculoskeletal Ageing ResearchSchool of Life SciencesUniversity of NottinghamNottinghamUK
| | - Francis B. Stephens
- Department of Sport and Health SciencesSt Luke's CampusUniversity of ExeterExeterUK
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11
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The Regulation of Fat Metabolism During Aerobic Exercise. Biomolecules 2020; 10:biom10121699. [PMID: 33371437 PMCID: PMC7767423 DOI: 10.3390/biom10121699] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/09/2020] [Accepted: 12/15/2020] [Indexed: 12/19/2022] Open
Abstract
Since the lipid profile is altered by physical activity, the study of lipid metabolism is a remarkable element in understanding if and how physical activity affects the health of both professional athletes and sedentary subjects. Although not fully defined, it has become clear that resistance exercise uses fat as an energy source. The fatty acid oxidation rate is the result of the following processes: (a) triglycerides lipolysis, most abundant in fat adipocytes and intramuscular triacylglycerol (IMTG) stores, (b) fatty acid transport from blood plasma to muscle sarcoplasm, (c) availability and hydrolysis rate of intramuscular triglycerides, and (d) transport of fatty acids through the mitochondrial membrane. In this review, we report some studies concerning the relationship between exercise and the aforementioned processes also in light of hormonal controls and molecular regulations within fat and skeletal muscle cells.
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12
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Sawicka AK, Renzi G, Olek RA. The bright and the dark sides of L-carnitine supplementation: a systematic review. J Int Soc Sports Nutr 2020; 17:49. [PMID: 32958033 PMCID: PMC7507632 DOI: 10.1186/s12970-020-00377-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 09/04/2020] [Indexed: 12/16/2022] Open
Abstract
Background L-carnitine (LC) is used as a supplement by recreationally-active, competitive and highly trained athletes. This systematic review aims to evaluate the effect of prolonged LC supplementation on metabolism and metabolic modifications. Methods A literature search was conducted in the MEDLINE (via PubMed) and Web of Science databases from the inception up February 2020. Eligibility criteria included studies on healthy human subjects, treated for at least 12 weeks with LC administered orally, with no drugs or any other multi-ingredient supplements co-ingestion. Results The initial search retrieved 1024 articles, and a total of 11 studies were finally included after applying inclusion and exclusion criteria. All the selected studies were conducted with healthy human subjects, with supplemented dose ranging from 1 g to 4 g per day for either 12 or 24 weeks. LC supplementation, in combination with carbohydrates (CHO) effectively elevated total carnitine content in skeletal muscle. Twenty-four-weeks of LC supplementation did not affect muscle strength in healthy aged women, but significantly increased muscle mass, improved physical effort tolerance and cognitive function in centenarians. LC supplementation was also noted to induce an increase of fasting plasma trimethylamine-N-oxide (TMAO) levels, which was not associated with modification of determined inflammatory nor oxidative stress markers. Conclusion Prolonged LC supplementation in specific conditions may affect physical performance. On the other hand, LC supplementation elevates fasting plasma TMAO, compound supposed to be pro-atherogenic. Therefore, additional studies focusing on long-term supplementation and its longitudinal effect on the cardiovascular system are needed.
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Affiliation(s)
- Angelika K Sawicka
- Department of Human Physiology, Faculty of Health Sciences, Medical University of Gdansk, 80-210, Gdansk, Poland
| | | | - Robert A Olek
- Department of Athletics, Strength and Conditioning, Poznan University of Physical Education, Krolowej Jadwigi 27/39, 61-871, Poznan, Poland.
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13
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Watanabe M, Risi R, Masi D, Caputi A, Balena A, Rossini G, Tuccinardi D, Mariani S, Basciani S, Manfrini S, Gnessi L, Lubrano C. Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review. Nutrients 2020; 12:E2873. [PMID: 32962190 PMCID: PMC7551574 DOI: 10.3390/nu12092873] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/14/2020] [Accepted: 09/18/2020] [Indexed: 02/06/2023] Open
Abstract
The use of food supplements for weight loss purposes has rapidly gained popularity as the prevalence of obesity increases. Navigating through the vast, often low quality, literature available is challenging, as is providing informed advice to those asking for it. Herein, we provide a comprehensive literature revision focusing on most currently marketed dietary supplements claimed to favor weight loss, classifying them by their purported mechanism of action. We conclude by proposing a combination of supplements most supported by current evidence, that leverages all mechanisms of action possibly leading to a synergistic effect and greater weight loss in the foreseen absence of adverse events. Further studies will be needed to confirm the weight loss and metabolic improvement that may be obtained through the use of the proposed combination.
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Affiliation(s)
- Mikiko Watanabe
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Renata Risi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Davide Masi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Alessandra Caputi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Angela Balena
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Giovanni Rossini
- Department of Endocrinology and Diabetes, University Campus Bio-Medico of Rome, 00128 Rome, Italy; (G.R.); (D.T.); (S.M.)
| | - Dario Tuccinardi
- Department of Endocrinology and Diabetes, University Campus Bio-Medico of Rome, 00128 Rome, Italy; (G.R.); (D.T.); (S.M.)
| | - Stefania Mariani
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Sabrina Basciani
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Silvia Manfrini
- Department of Endocrinology and Diabetes, University Campus Bio-Medico of Rome, 00128 Rome, Italy; (G.R.); (D.T.); (S.M.)
| | - Lucio Gnessi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Carla Lubrano
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
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14
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Hargreaves M, Spriet LL. Skeletal muscle energy metabolism during exercise. Nat Metab 2020; 2:817-828. [PMID: 32747792 DOI: 10.1038/s42255-020-0251-4] [Citation(s) in RCA: 411] [Impact Index Per Article: 102.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/25/2020] [Indexed: 12/12/2022]
Abstract
The continual supply of ATP to the fundamental cellular processes that underpin skeletal muscle contraction during exercise is essential for sports performance in events lasting seconds to several hours. Because the muscle stores of ATP are small, metabolic pathways must be activated to maintain the required rates of ATP resynthesis. These pathways include phosphocreatine and muscle glycogen breakdown, thus enabling substrate-level phosphorylation ('anaerobic') and oxidative phosphorylation by using reducing equivalents from carbohydrate and fat metabolism ('aerobic'). The relative contribution of these metabolic pathways is primarily determined by the intensity and duration of exercise. For most events at the Olympics, carbohydrate is the primary fuel for anaerobic and aerobic metabolism. Here, we provide an overview of exercise metabolism and the key regulatory mechanisms ensuring that ATP resynthesis is closely matched to the ATP demand of exercise. We also summarize various interventions that target muscle metabolism for ergogenic benefit in athletic events.
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Affiliation(s)
- Mark Hargreaves
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Lawrence L Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
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15
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Cheung WW, Ding W, Hoffman HM, Wang Z, Hao S, Zheng R, Gonzalez A, Zhan JY, Zhou P, Li S, Esparza MC, Lieber RL, Mak RH. Vitamin D ameliorates adipose browning in chronic kidney disease cachexia. Sci Rep 2020; 10:14175. [PMID: 32843714 PMCID: PMC7447759 DOI: 10.1038/s41598-020-70190-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/21/2020] [Indexed: 12/15/2022] Open
Abstract
Patients with chronic kidney disease (CKD) are often 25(OH)D3 and 1,25(OH)2D3 insufficient. We studied whether vitamin D repletion could correct aberrant adipose tissue and muscle metabolism in a mouse model of CKD-associated cachexia. Intraperitoneal administration of 25(OH)D3 and 1,25(OH)2D3 (75 μg/kg/day and 60 ng/kg/day respectively for 6 weeks) normalized serum concentrations of 25(OH)D3 and 1,25(OH)2D3 in CKD mice. Vitamin D repletion stimulated appetite, normalized weight gain, and improved fat and lean mass content in CKD mice. Vitamin D supplementation attenuated expression of key molecules involved in adipose tissue browning and ameliorated expression of thermogenic genes in adipose tissue and skeletal muscle in CKD mice. Furthermore, repletion of vitamin D improved skeletal muscle fiber size and in vivo muscle function, normalized muscle collagen content and attenuated muscle fat infiltration as well as pathogenetic molecular pathways related to muscle mass regulation in CKD mice. RNAseq analysis was performed on the gastrocnemius muscle. Ingenuity Pathway Analysis revealed that the top 12 differentially expressed genes in CKD were correlated with impaired muscle and neuron regeneration, enhanced muscle thermogenesis and fibrosis. Importantly, vitamin D repletion normalized the expression of those 12 genes in CKD mice. Vitamin D repletion may be an effective therapeutic strategy for adipose tissue browning and muscle wasting in CKD patients.
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MESH Headings
- Adipocytes, Beige/drug effects
- Adipocytes, Beige/metabolism
- Adipocytes, Brown/metabolism
- Adipocytes, White/metabolism
- Animals
- Cachexia/drug therapy
- Cachexia/etiology
- Cachexia/physiopathology
- Calcifediol/blood
- Calcifediol/deficiency
- Calcifediol/pharmacology
- Calcifediol/therapeutic use
- Calcitriol/blood
- Calcitriol/deficiency
- Calcitriol/pharmacology
- Calcitriol/therapeutic use
- Disease Models, Animal
- Eating/drug effects
- Fibrosis/genetics
- Gene Expression Regulation/drug effects
- Hand Strength
- Mice
- Mice, Inbred C57BL
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/pathology
- Nephrectomy
- Parathyroid Hormone/blood
- RNA, Messenger/biosynthesis
- Renal Insufficiency, Chronic/blood
- Renal Insufficiency, Chronic/complications
- Renal Insufficiency, Chronic/drug therapy
- Rotarod Performance Test
- Sequence Analysis, RNA
- Thermogenesis/drug effects
- Weight Gain/drug effects
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Affiliation(s)
- Wai W Cheung
- Pediatric Nephrology, Rady Children's Hospital San Diego, University of California, San Diego, USA
| | - Wei Ding
- Division of Nephrology, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Hal M Hoffman
- Department of Pediatrics, University of California, San Diego, USA
| | - Zhen Wang
- Department of Pediatrics, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Sheng Hao
- Department of Nephrology and Rheumatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Ronghao Zheng
- Department of Pediatrics, Hubei Maternal and Child Health Hospital, Wuhan, China
| | - Alex Gonzalez
- Pediatric Nephrology, Rady Children's Hospital San Diego, University of California, San Diego, USA
| | - Jian-Ying Zhan
- Children's Hospital, Zhejiang University, Hangzhou, China
| | - Ping Zhou
- Department of Pediatrics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Shiping Li
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China
| | - Mary C Esparza
- Department of Orthopedic Surgery, University of California, San Diego, USA
| | - Richard L Lieber
- Shirley Ryan AbilityLab and Northwestern University, Chicago, USA
| | - Robert H Mak
- Pediatric Nephrology, Rady Children's Hospital San Diego, University of California, San Diego, USA.
- Division of Pediatric Nephrology, Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, MC 0831, La Jolla, CA, 92093-0831, USA.
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16
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Varney JL, Fowler JW, McClaughry TC, Vignale K, Caldas J, Weil JT, Coon CN. L-Carnitine metabolism, protein turnover and energy expenditure in supplemented and exercised Labrador Retrievers. J Anim Physiol Anim Nutr (Berl) 2020; 104:1540-1550. [PMID: 32557872 PMCID: PMC7540169 DOI: 10.1111/jpn.13391] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 03/24/2020] [Accepted: 04/30/2020] [Indexed: 11/28/2022]
Abstract
L-Carnitine is critical for protection against bioaccumulation, long-chain fatty acid transportation and energy production. Energy production becomes important as the body maintains lean mass, repairs muscles and recovers from oxidative stress. The aim was to investigate the effects of supplemented L-carnitine on protein turnover (PT), energy expenditure (EE) and carnitine metabolism in muscle/serum of Labrador Retrievers. In a series of experiments, all dogs were fed a low-carnitine diet and sorted into one of two groups: L-carnitine (LC) supplemented daily with 125 mg L-carnitine and 3.75 g sucrose or placebo (P) supplemented with 4 g sucrose daily. The experiments consisted of analyses of muscle/serum for L-carnitine content (EXP1), a protein turnover experiment (EXP2) and analysis of substrate utilization via indirect calorimetry (EXP3). EXP1: 20 Labradors (10 M/10 F) performed a 13 week running regimen. L-Carnitine content was analysed in the serum and biceps femoris muscle before/after a 24.1 km run. LC serum had higher total (p < .001; p = .001), free (p < .001; p = .001) and esterified (p = .001; p = .003) L-carnitine pre- and post-run respectively. LC muscle had significantly higher free L-carnitine post-run (p = .034). EXP2: 26 Labs (13 M/13 F) performed a 60-day running regimen. For the final run, half of the Labradors from each treatment rested and half ran 24.1 km. Twenty-four Labradors received isotope infusion, and then, a biopsy of the biceps femoris of all 26 Labradors was taken to determine PT. Resting/exercised LC had a lower fractional breakdown rate (FBR) versus P group (p = .042). LC females had a lower FBR v. P females (p = .046). EXP3: Respiration of 16 Labradors (8 M/8 F) was measured via indirect calorimetry over 15 week. All dogs ran on a treadmill for 30 min at 30% VO2 max (6.5 kph), resulting in higher maximum and mean EE in LC females v. P females (p = .021; p = .035). Implications for theory, practice and future research are discussed.
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17
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Bruls YM, de Ligt M, Lindeboom L, Phielix E, Havekes B, Schaart G, Kornips E, Wildberger JE, Hesselink MK, Muoio D, Schrauwen P, Schrauwen-Hinderling VB. Carnitine supplementation improves metabolic flexibility and skeletal muscle acetylcarnitine formation in volunteers with impaired glucose tolerance: A randomised controlled trial. EBioMedicine 2019; 49:318-330. [PMID: 31676389 PMCID: PMC6945245 DOI: 10.1016/j.ebiom.2019.10.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/10/2019] [Accepted: 10/10/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Type 2 diabetes patients and individuals at risk of developing diabetes are characterized by metabolic inflexibility and disturbed glucose homeostasis. Low carnitine availability may contribute to metabolic inflexibility and impaired glucose tolerance. Here, we investigated whether carnitine supplementation improves metabolic flexibility and insulin sensitivity in impaired glucose tolerant (IGT) volunteers. METHODS Eleven IGT- volunteers followed a 36-day placebo- and L-carnitine treatment (2 g/day) in a randomised, placebo-controlled, double blind crossover design. A hyperinsulinemic-euglycemic clamp (40 mU/m2/min), combined with indirect calorimetry (ventilated hood) was performed to determine insulin sensitivity and metabolic flexibility. Furthermore, metabolic flexibility was assessed in response to a high-energy meal. Skeletal muscle acetylcarnitine concentrations were measured in vivo using long echo time proton magnetic resonance spectroscopy (1H-MRS, TE=500 ms) in the resting state (7:00AM and 5:00PM) and after a 30-min cycling exercise. Twelve normal glucose tolerant (NGT) volunteers were included without any intervention as control group. RESULTS Metabolic flexibility of IGT-subjects completely restored towards NGT control values upon carnitine supplementation, measured during a hyperinsulinemic-euglycemic clamp and meal test. In muscle, carnitine supplementation enhanced the increase in resting acetylcarnitine concentrations over the day (delta 7:00 AM versus 5:00 PM) in IGT-subjects. Furthermore, carnitine supplementation increased post-exercise acetylcarnitine concentrations and reduced long-chain acylcarnitine species in IGT-subjects, suggesting the stimulation of a more complete fat oxidation in muscle. Whole-body insulin sensitivity was not affected. CONCLUSION Carnitine supplementation improves acetylcarnitine formation and rescues metabolic flexibility in IGT-subjects. Future research should investigate the potential of carnitine in prevention/treatment of type 2 diabetes.
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Affiliation(s)
- Yvonne Mh Bruls
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands; Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Marlies de Ligt
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Lucas Lindeboom
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands; Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Esther Phielix
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Bas Havekes
- Department of Internal Medicine, Division of Endocrinology, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Gert Schaart
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Esther Kornips
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Joachim E Wildberger
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Matthijs Kc Hesselink
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Deborah Muoio
- Department of Medicine, Duke University Medical Center, Durham, NC NC22704, United States of America
| | - Patrick Schrauwen
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Vera B Schrauwen-Hinderling
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands; Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands.
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19
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van de Weijer T, Schrauwen-Hinderling VB. Application of Magnetic Resonance Spectroscopy in metabolic research. Biochim Biophys Acta Mol Basis Dis 2019; 1865:741-748. [DOI: 10.1016/j.bbadis.2018.09.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 09/08/2018] [Accepted: 09/10/2018] [Indexed: 02/08/2023]
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20
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Vallance HD, Koochin A, Branov J, Rosen-Heath A, Bosdet T, Wang Z, Hazen SL, Horvath G. Marked elevation in plasma trimethylamine-N-oxide (TMAO) in patients with mitochondrial disorders treated with oral l-carnitine. Mol Genet Metab Rep 2018; 15:130-133. [PMID: 30023305 PMCID: PMC6047224 DOI: 10.1016/j.ymgmr.2018.04.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/20/2018] [Accepted: 04/20/2018] [Indexed: 11/26/2022] Open
Abstract
Oral supplementation with l-carnitine is a common therapeutic modality for mitochondrial disorders despite limited evidence of efficacy. Recently, a number of studies have demonstrated that a gut microbiota-dependent metabolite of l-carnitine, trimethylamine oxide (TMAO), is an independent and dose-dependent risk factor for cardiovascular disease (CVD). Given the limited data demonstrating efficacy with oral l-carnitine therapy and the newly raised questions of potential harm, we assessed plasma TMAO levels in patients with mitochondrial disease with and without oral l-carnitine supplementation. Nine subjects were recruited and completed the study. Eight out of 9 subjects at baseline had plasma TMAO concentrations <97.5th percentile (<15.5 μM). One subject with stage 3 renal disease, had marked elevation in plasma TMAO (pre 33.98 μm versus post 101.6 μm). Following at least 3 months of l-carnitine supplementation (1000 mg per day), plasma TMAO levels were markedly increased in 7out of 9 subjects; overall, plasma TMAO significantly increased 11.8-fold (p < 0.001) from a baseline median level of 3.54 μm (interquartile range (IQR) 2.55–8.72) to 43.26 (IQR 23.99–56.04) post supplementation. The results of this study demonstrate that chronic oral l-carnitine supplementation markedly increases plasma TMAO levels in subjects with mitochondrial disorders. Further studies to evaluate both the efficacy and long term safety of oral l-carnitine supplementation for the treatment of mitochondrial disorders are warranted.
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Affiliation(s)
- H D Vallance
- Biochemical Genetics laboratory, Department of Pathology and Laboratory Medicine, BC Children's Hospital, 4480 Oak Street, Vancouver, BC, Canada
| | - A Koochin
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
| | - J Branov
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
| | - A Rosen-Heath
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
| | - T Bosdet
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
| | - Z Wang
- Department of Cellular and Molecular Medicine, Center for Microbiome & Human Health, Lerner Research Institute, Cleveland Clinic, OH 44195, USA
| | - S L Hazen
- Department of Cellular and Molecular Medicine, Center for Microbiome & Human Health, Lerner Research Institute, Cleveland Clinic, OH 44195, USA.,Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH 44195,USA
| | - G Horvath
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
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Abstract
Given its pivotal role in fatty acid oxidation and energy metabolism, l-carnitine has been investigated as ergogenic aid for enhancing exercise capacity in the healthy athletic population. Early research indicates its beneficial effects on acute physical performance, such as increased maximum oxygen consumption and higher power output. Later studies point to the positive impact of dietary supplementation with l-carnitine on the recovery process after exercise. It is demonstrated that l-carnitine alleviates muscle injury and reduces markers of cellular damage and free radical formation accompanied by attenuation of muscle soreness. The supplementation-based increase in serum and muscle l-carnitine contents is suggested to enhance blood flow and oxygen supply to the muscle tissue via improved endothelial function thereby reducing hypoxia-induced cellular and biochemical disruptions. Studies in older adults further showed that l-carnitine intake can lead to increased muscle mass accompanied by a decrease in body weight and reduced physical and mental fatigue. Based on current animal studies, a role of l-carnitine in the prevention of age-associated muscle protein degradation and regulation of mitochondrial homeostasis is suggested.
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Affiliation(s)
- Roger Fielding
- Tufts University, 136 Harrison Avenue, Boston, MA 02111, USA.
| | - Linda Riede
- analyze & realize GmbH, Waldseeweg 6, 13467 Berlin, Germany.
| | - James P Lugo
- Lonza Inc., 90 Boroline Road, Allendale, NJ 07401, USA.
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Bardanzellu F, Fanos V, Strigini FAL, Artini PG, Peroni DG. Human Breast Milk: Exploring the Linking Ring Among Emerging Components. Front Pediatr 2018; 6:215. [PMID: 30131948 PMCID: PMC6091001 DOI: 10.3389/fped.2018.00215] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/13/2018] [Indexed: 12/19/2022] Open
Abstract
Maternal breast milk (BM) is a complex and unique fluid that evolution adapted to satisfy neonatal needs; in addition to classical nutrients, it contains several bioactive components. BM characteristically shows inter-individual variability, modifying its composition during different phases of lactation. BM composition, determining important consequences on neonatal gut colonization, influences both short and long-term development. Maternal milk can also shape neonatal microbiota, through its glycobiome rich in Lactobacilli spp. and Bifidobacteria spp. Therefore, neonatal nourishment during the first months of life seems the most important determinant of individual's outcomes. Our manuscript aims to provide new evidence in the characterization of BM metabolome and microbiome, and its comparison to formula milk, allowing the evaluation of each nutrient's influence on neonatal metabolism. This result very interesting since potentially offers an innovative approach to investigate the complex relationship between BM components and infant's health, also providing the chance to intervene in a sartorial way on diet composition, according to the nutritional requests. Future research, integrating metabolomics, microbiomics and stem cells knowledge, could make significant steps forward in understanding BM extraordinary properties and functions.
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Affiliation(s)
- Flaminia Bardanzellu
- Neonatal Intensive Care Unit, Neonatal Pathology and Neonatal Section, Azienda Ospedaliera Universitaria di Cagliari, University of Cagliari, Cagliari, Italy
| | - Vassilios Fanos
- Neonatal Intensive Care Unit, Neonatal Pathology and Neonatal Section, Azienda Ospedaliera Universitaria di Cagliari, University of Cagliari, Cagliari, Italy
| | | | - Paolo G Artini
- Gynecology and Obstetrics, Università degli Studi di Pisa, Pisa, Italy
| | - Diego G Peroni
- Section of Pediatric, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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Choi JW, Ohn JH, Jung HS, Park YJ, Jang HC, Chung SS, Park KS. Carnitine induces autophagy and restores high-fat diet-induced mitochondrial dysfunction. Metabolism 2018; 78:43-51. [PMID: 28966077 DOI: 10.1016/j.metabol.2017.09.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/12/2017] [Accepted: 09/23/2017] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Autophagy is suppressed in skeletal muscle and the liver with insulin resistance induced by a high-fat diet. Autophagy is essential for maintaining mitochondrial function, and dysfunctional mitochondria are associated with insulin resistance. As carnitine treatment is well known to improve insulin resistance by promoting mitochondrial function, we investigated if carnitine affects autophagy in the skeletal muscle of a high-fat diet-induced rodent model of obesity. RESULTS After 6weeks on a high-fat diet (48kcal% fat), mice developed glucose intolerance, and the gastrocnemius muscle showed a decrease in insulin signaling and mitochondrial function, which was reversed after carnitine (100mg/kg/day) treatment by oral gavage for 2weeks. Swollen mitochondria with destroyed cristae were observed in the skeletal muscle of high-fat diet-fed mice but were not there after carnitine treatment. High-fat diet decreased LC3B-II, a marker of autophagosome formation, and increased sequestosome 1 (SQSTM1), expression of which was reversed after carnitine treatment. In C2C12 myotubes, prolonged treatment with palmitate suppressed autophagy, which was relieved by carnitine treatment. However, the induction of autophagy by carnitine in C2C12 myotubes was not observed after knock-down of peroxisome proliferator-activated receptor γ (PPARγ), which is known to regulate autophagy. CONCLUSION We conclude that the removal of dysfunctional mitochondria by induction of autophagy through PPARγ may be a novel mechanism by which carnitine improves insulin resistance and mitochondrial dysfunction in obesity.
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Affiliation(s)
- Jin Woo Choi
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Jung Hun Ohn
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Hye Seung Jung
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Young Joo Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hak Chul Jang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Sung Soo Chung
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
| | - Kyong Soo Park
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
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Reproduction affects locomotor behaviour and muscle physiology in the sea cucumber, Apostichopus japonicus. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.09.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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25
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Abstract
Fat and carbohydrate are the major fuel sources utilised for oxidative, mitochondrial ATP resynthesis during human skeletal muscle contraction. The relative contribution of these two substrates to ATP resynthesis and total energy expenditure during exercise can vary substantially, and is predominantly determined by fuel availability and exercise intensity and duration. For example, the increased ATP demand that occurs with an increase in exercise intensity is met by increases in both fat and carbohydrate oxidation up to an intensity of approximately 60-70 % of maximal oxygen consumption. When exercise intensity increases beyond this workload, skeletal muscle carbohydrate utilisation is accelerated, which results in a reduction and inhibition of the relative and absolute contribution of fat oxidation to total energy expenditure. However, the precise mechanisms regulating muscle fuel selection and underpinning the decline in fat oxidation remain unclear. This brief review will primarily address the theory that a carbohydrate flux-mediated reduction in the availability of muscle carnitine to the mitochondrial enzyme carnitine palmitoyltransferase 1, a rate-limiting step in mitochondrial fat translocation, is a key mechanism for the decline in fat oxidation during high-intensity exercise. This is discussed in relation to recent work in this area investigating fuel metabolism at various exercise intensities and taking advantage of the discovery that skeletal muscle carnitine content can be nutritionally increased in vivo in human subjects.
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Abstract
Manipulating thermogenesis could increase energy expenditure and improve metabolism. Brown fat is a major site of nonshivering thermogenesis, but other tissues, notably muscle and liver, can contribute to cold adaptation. In this issue, Simcox et al. (2017) demonstrate in cold-exposed mice that liver-generated acylcarnitines are required to fuel thermogenesis.
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Affiliation(s)
- Nada A Abumrad
- Medicine and Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA.
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Krähenbühl S. Importance of the skeletal muscle carnitine stores in fuel selection. J Physiol 2017; 595:5727-5728. [DOI: 10.1113/jp274755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Stephan Krähenbühl
- Clinical Pharmacology & Toxicology; University Hospital Basel; Basel Switzerland
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Bardanzellu F, Fanos V, Reali A. "Omics" in Human Colostrum and Mature Milk: Looking to Old Data with New Eyes. Nutrients 2017; 9:E843. [PMID: 28783113 PMCID: PMC5579636 DOI: 10.3390/nu9080843] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/02/2017] [Accepted: 08/04/2017] [Indexed: 12/21/2022] Open
Abstract
Human Milk (HM) is the best source for newborn nutrition until at least six months; it exerts anti-inflammatory and anti-infective functions, promotes immune system formation and supports organ development. Breastfeeding could also protect from obesity, diabetes and cardiovascular disease. Furthermore, human colostrum (HC) presents a peculiar role in newborn support as a protective effect against allergic and chronic diseases, in addition to long-term metabolic benefits. In this review, we discuss the recent literature regarding "omics" technologies and growth factors (GF) in HC and the effects of pasteurization on its composition. Our aim was to provide new evidence in terms of transcriptomics, proteomics, metabolomics, and microbiomics, also in relation to maternal metabolic diseases and/or fetal anomalies and to underline the functions of GF. Since HC results are so precious, particularly for the vulnerable pre-terms category, we also discuss the importance of HM pasteurization to ensure donated HC even to neonates whose mothers are unable to provide. To the best of our knowledge, this is the first review analyzing in detail the molecular pattern, microbiota, bioactive factors, and dynamic profile of HC, finding clinical correlations of such mediators with their possible in vivo effects and with the consequent impact on neonatal outcomes.
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Affiliation(s)
- Flaminia Bardanzellu
- Neonatal Intensive Care Unit, Neonatal Pathology and Neonatal Section, AOU and University of Cagliari, 09124 Cagliari, Italy.
| | - Vassilios Fanos
- Neonatal Intensive Care Unit, Neonatal Pathology and Neonatal Section, AOU and University of Cagliari, 09124 Cagliari, Italy.
| | - Alessandra Reali
- Neonatal Intensive Care Unit, Neonatal Pathology and Neonatal Section, AOU and University of Cagliari, 09124 Cagliari, Italy.
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Porter C, Constantin-Teodosiu D, Constantin D, Leighton B, Poucher SM, Greenhaff PL. Muscle carnitine availability plays a central role in regulating fuel metabolism in the rodent. J Physiol 2017; 595:5765-5780. [PMID: 28605113 DOI: 10.1113/jp274415] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/31/2017] [Indexed: 01/05/2023] Open
Abstract
KEY POINTS Meldonium inhibits endogenous carnitine synthesis and tissue uptake, and accelerates urinary carnitine excretion, although the impact of meldonium-mediated muscle carnitine depletion on whole-body fuel selection, and muscle fuel metabolism and its molecular regulation is under-investigated. Ten days of oral meldonium administration did not impact on food or fluid intake, physical activity levels or body weight gain in the rat, whereas it depleted muscle carnitine content (all moieties), increased whole-body carbohydrate oxidation and muscle and liver glycogen utilization, and reduced whole-body fat oxidation. Meldonium reduced carnitine transporter protein expression across muscles of different contractile and metabolic phenotypes. A TaqMan PCR low-density array card approach revealed the abundance of 189 mRNAs regulating fuel selection was altered in soleus muscle by meldonium, highlighting the modulation of discrete cellular functions and metabolic pathways. These novel findings strongly support the premise that muscle carnitine availability is a primary regulator of fuel selection in vivo. ABSTRACT The body carnitine pool is primarily confined to skeletal muscle, where it regulates carbohydrate (CHO) and fat usage. Meldonium (3-(2,2,2-trimethylhydrazinium)-propionate) inhibits carnitine synthesis and tissue uptake, although the impact of carnitine depletion on whole-body fuel selection, muscle fuel metabolism and its molecular regulation is under-investigated. Male lean Zucker rats received water (control, n = 8) or meldonium-supplemented water (meldonium, n = 8) for 10 days [1.6 g kg-1 body mass (BM) day-1 days 1-2, 0.8 g kg-1 BM day-1 thereafter]. From days 7-10, animals were housed in indirect calorimetry chambers after which soleus muscle and liver were harvested. Food and fluid intake, weight gain and physical activity levels were similar between groups from days 7 to 10. Compared to control, meldonium depleted muscle total carnitine (P < 0.001) and all carnitine esters. Furthermore, whole-body fat oxidation was less (P < 0.001) and CHO oxidation was greater (P < 0.05) compared to the control, whereas soleus and liver glycogen contents were less (P < 0.01 and P < 0.01, respectively). In a second study, male Wistar rats received water (n = 8) or meldonium-supplemented water (n = 8) as above, and kidney, heart and extensor digitorum longus muscle (EDL) and soleus muscles were collected. Compared to control, meldonium depleted total carnitine content (all P < 0.001), reduced carnitine transporter protein and glycogen content, and increased pyruvate dehydrogenase kinase 4 mRNA abundance in the heart, EDL and soleus. In total, 189 mRNAs regulating fuel selection were differentially expressed in soleus in meldonium vs. control, and a number of cellular functions and pathways strongly associated with carnitine depletion were identified. Collectively, these data firmly support the premise that muscle carnitine availability is a primary regulator of fuel selection in vivo.
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Affiliation(s)
- Craig Porter
- MRC/ARUK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Nottingham, UK
| | - Dumitru Constantin-Teodosiu
- MRC/ARUK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Nottingham, UK
| | - Despina Constantin
- MRC/ARUK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Nottingham, UK
| | | | | | - Paul L Greenhaff
- MRC/ARUK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Nottingham, UK
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Shannon CE, Ghasemi R, Greenhaff PL, Stephens FB. Increasing skeletal muscle carnitine availability does not alter the adaptations to high-intensity interval training. Scand J Med Sci Sports 2017; 28:107-115. [PMID: 28345160 DOI: 10.1111/sms.12885] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2017] [Indexed: 11/27/2022]
Abstract
Increasing skeletal muscle carnitine availability alters muscle metabolism during steady-state exercise in healthy humans. We investigated whether elevating muscle carnitine, and thereby the acetyl-group buffering capacity, altered the metabolic and physiological adaptations to 24 weeks of high-intensity interval training (HIIT) at 100% maximal exercise capacity (Wattmax ). Twenty-one healthy male volunteers (age 23±2 years; BMI 24.2±1.1 kg/m2 ) performed 2 × 3 minute bouts of cycling exercise at 100% Wattmax , separated by 5 minutes of rest. Fourteen volunteers repeated this protocol following 24 weeks of HIIT and twice-daily consumption of 80 g carbohydrate (CON) or 3 g l-carnitine+carbohydrate (CARN). Before HIIT, muscle phosphocreatine (PCr) degradation (P<.0001), glycogenolysis (P<.0005), PDC activation (P<.05), and acetylcarnitine (P<.005) were 2.3-, 2.1-, 1.5-, and 1.5-fold greater, respectively, in exercise bout two compared to bout 1, while lactate accumulation tended (P<.07) to be 1.5-fold greater. Following HIIT, muscle free carnitine was 30% greater in CARN vs CON at rest and remained 40% elevated prior to the start of bout 2 (P<.05). Following bout 2, free carnitine content, PCr degradation, glycogenolysis, lactate accumulation, and PDC activation were all similar between CON and CARN, albeit markedly lower than before HIIT. VO2max , Wattmax , and work output were similarly increased in CON and CARN, by 9, 15, and 23% (P<.001). In summary, increased reliance on non-mitochondrial ATP resynthesis during a second bout of intense exercise is accompanied by increased carnitine acetylation. Augmenting muscle carnitine during 24 weeks of HIIT did not alter this, nor did it enhance muscle metabolic adaptations or performance gains beyond those with HIIT alone.
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Affiliation(s)
- Christopher E Shannon
- MRC/ARUK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Nottingham, UK.,Diabetes Division, University of Texas Health Science Centre, San Antonio, TX, USA
| | - Reza Ghasemi
- MRC/ARUK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Paul L Greenhaff
- MRC/ARUK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Francis B Stephens
- MRC/ARUK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Nottingham, UK.,Sport and Health Sciences, University of Exeter, Exeter, UK
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Intramyocellular lipid content and lipogenic gene expression responses following a single bout of resistance type exercise differ between young and older men. Exp Gerontol 2017; 93:36-45. [PMID: 28385599 DOI: 10.1016/j.exger.2017.03.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/07/2017] [Accepted: 03/28/2017] [Indexed: 11/21/2022]
Abstract
The aim of this study was to examine the temporal relationship between intramyocellular lipid (IMCL) content and the expression of genes associated with IMCL turnover, fat metabolism, and inflammation during recovery from an acute bout of resistance type exercise in old versus young men. Seven healthy young (23±2years, 77.2±2.9kg) and seven healthy older (72±1years, 79.3±4.9kg) males performed a single bout of resistance exercise involving 6 sets of 10 repetitions of leg press and 6 sets of 10 repetitions of leg extension at 75% one-repetition maximum (1-RM). Muscle biopsy samples were obtained before and 12, 24 and 48h after the completion of exercise and analysed for IMCL content and the expression of 48 genes. The subjects refrained from further heavy physical exercise and consumed a standardized diet for the entire experimental period. The IMCL content was ~2-fold higher at baseline and 12h post-exercise in old compared with young individuals. However, no differences between groups were apparent after 48h of recovery. There was higher expression of genes involved in fatty acid synthesis (FASN and PPARγ) during the first 24h of recovery. Differential responses to exercise were observed between groups for a number of genes indicating increased inflammatory response (IL6, IkBalpha, CREB1) and impaired fat metabolism and TCA cycle (LPL, ACAT1, SUCLG1) in older compared with younger individuals. A singe bout of resistance type exercise leads to molecular changes in skeletal muscle favouring reduced lipid oxidation, increased lipogenesis, and exaggerated inflammation during post-exercise recovery in the older compared with younger individuals, which may be indicative of a blunted response of IMCL turnover with ageing.
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Utilisation of supplemented l-carnitine for fuel efficiency, as an antioxidant, and for muscle recovery in Labrador retrievers. J Nutr Sci 2017; 6:e8. [PMID: 28620483 PMCID: PMC5465856 DOI: 10.1017/jns.2017.4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/01/2016] [Accepted: 01/05/2017] [Indexed: 11/30/2022] Open
Abstract
The primary goal was to investigate the effects of l-carnitine on fuel efficiency, as an antioxidant, and for muscle recovery in Labrador retrievers. Dogs were split into two groups, with one group being supplemented with 250 mg/d of Carniking™ l-carnitine powder. Two experiments (Expt 1 and Expt 2) were performed over a 2-year period which included running programmes, activity monitoring, body composition scans and evaluation of recovery using biomarkers. Each experiment differed slightly in dog number and design: fifty-six v. forty dogs; one endurance and two sprint runs per week v. two endurance runs; and differing blood collection time points. All dogs were fed a low-carnitine diet in which a fixed amount was offered based on maintaining the minimum starting weight. Results from Expt 1 found that the carnitine dogs produced approximately 4000 more activity points per km compared with the control group during sprint (P = 0·052) and endurance runs (P = 0·0001). Male carnitine dogs produced half the creatine phosphokinase (CPK) following exercise compared with male control dogs (P = 0·05). Carnitine dogs had lower myoglobin at 6·69 ng/ml following intensive exercise compared with controls at 24·02 ng/ml (P = 0·0295). Total antioxidant capacity (TAC) and thiobarbituric acid reactive substance (TBARS) results were not considered significant. In Expt 2, body composition scans indicated that the carnitine group gained more total tissue mass while controls lost tissue mass (P = 0·0006) and also gained lean mass while the control group lost lean mass (P < 0·0001). Carnitine dogs had lower CPK secretion at 23·06 v. control at 28·37 mU/ml 24 h after post-run (P = 0·003). Myoglobin levels were lower in carnitine v. control dogs both 1 h post-run (P = 0·0157; 23·83 v. 37·91 ng/ml) and 24 h post-run (P = 0·0189; 6·25 v.13·5 ng/ml). TAC indicated more antioxidant activity in carnitine dogs at 0·16 mmv. control at 0·13 mm (P = 0·0496). TBARS were also significantly lower in carnitine dogs both pre-run (P = 0·0013; 15·36 v. 23·42 µm) and 1 h post-run (P = 0·056; 16·45 v. 20·65 µm). Supplementing l-carnitine in the form of Carniking™ had positive benefits in Labrador retrievers for activity intensity, body composition, muscle recovery and oxidative capacity.
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Deane CS, Wilkinson DJ, Phillips BE, Smith K, Etheridge T, Atherton PJ. "Nutraceuticals" in relation to human skeletal muscle and exercise. Am J Physiol Endocrinol Metab 2017; 312:E282-E299. [PMID: 28143855 PMCID: PMC5406990 DOI: 10.1152/ajpendo.00230.2016] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 01/25/2017] [Accepted: 01/25/2017] [Indexed: 12/16/2022]
Abstract
Skeletal muscles have a fundamental role in locomotion and whole body metabolism, with muscle mass and quality being linked to improved health and even lifespan. Optimizing nutrition in combination with exercise is considered an established, effective ergogenic practice for athletic performance. Importantly, exercise and nutritional approaches also remain arguably the most effective countermeasure for muscle dysfunction associated with aging and numerous clinical conditions, e.g., cancer cachexia, COPD, and organ failure, via engendering favorable adaptations such as increased muscle mass and oxidative capacity. Therefore, it is important to consider the effects of established and novel effectors of muscle mass, function, and metabolism in relation to nutrition and exercise. To address this gap, in this review, we detail existing evidence surrounding the efficacy of a nonexhaustive list of macronutrient, micronutrient, and "nutraceutical" compounds alone and in combination with exercise in relation to skeletal muscle mass, metabolism (protein and fuel), and exercise performance (i.e., strength and endurance capacity). It has long been established that macronutrients have specific roles and impact upon protein metabolism and exercise performance, (i.e., protein positively influences muscle mass and protein metabolism), whereas carbohydrate and fat intakes can influence fuel metabolism and exercise performance. Regarding novel nutraceuticals, we show that the following ones in particular may have effects in relation to 1) muscle mass/protein metabolism: leucine, hydroxyl β-methylbutyrate, creatine, vitamin-D, ursolic acid, and phosphatidic acid; and 2) exercise performance: (i.e., strength or endurance capacity): hydroxyl β-methylbutyrate, carnitine, creatine, nitrates, and β-alanine.
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Affiliation(s)
- Colleen S Deane
- Medical Research Council-Arthritis Research UK Centre of Excellence for Musculoskeletal Ageing Research and Clinical, Metabolic, and Molecular Physiology, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
- Faculty of Health and Social Science, Bournemouth University, Bournemouth, United Kingdom; and
- Department of Sport and Health Science, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Daniel J Wilkinson
- Medical Research Council-Arthritis Research UK Centre of Excellence for Musculoskeletal Ageing Research and Clinical, Metabolic, and Molecular Physiology, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
| | - Bethan E Phillips
- Medical Research Council-Arthritis Research UK Centre of Excellence for Musculoskeletal Ageing Research and Clinical, Metabolic, and Molecular Physiology, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
| | - Kenneth Smith
- Medical Research Council-Arthritis Research UK Centre of Excellence for Musculoskeletal Ageing Research and Clinical, Metabolic, and Molecular Physiology, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
| | - Timothy Etheridge
- Department of Sport and Health Science, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Philip J Atherton
- Medical Research Council-Arthritis Research UK Centre of Excellence for Musculoskeletal Ageing Research and Clinical, Metabolic, and Molecular Physiology, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom;
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Shaw A, Jeromson S, Watterson KR, Pediani JD, Gallagher IJ, Whalley T, Dreczkowski G, Brooks N, Galloway SD, Hamilton DL. Multiple AMPK activators inhibit l-carnitine uptake in C2C12 skeletal muscle myotubes. Am J Physiol Cell Physiol 2017; 312:C689-C696. [PMID: 28298333 DOI: 10.1152/ajpcell.00026.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 02/21/2017] [Accepted: 03/14/2017] [Indexed: 12/29/2022]
Abstract
Mutations in the gene that encodes the principal l-carnitine transporter, OCTN2, can lead to a reduced intracellular l-carnitine pool and the disease Primary Carnitine Deficiency. l-Carnitine supplementation is used therapeutically to increase intracellular l-carnitine. As AMPK and insulin regulate fat metabolism and substrate uptake, we hypothesized that AMPK-activating compounds and insulin would increase l-carnitine uptake in C2C12 myotubes. The cells express all three OCTN transporters at the mRNA level, and immunohistochemistry confirmed expression at the protein level. Contrary to our hypothesis, despite significant activation of PKB and 2DG uptake, insulin did not increase l-carnitine uptake at 100 nM. However, l-carnitine uptake was modestly increased at a dose of 150 nM insulin. A range of AMPK activators that increase intracellular calcium content [caffeine (10 mM, 5 mM, 1 mM, 0.5 mM), A23187 (10 μM)], inhibit mitochondrial function [sodium azide (75 μM), rotenone (1 μM), berberine (100 μM), DNP (500 μM)], or directly activate AMPK [AICAR (250 μM)] were assessed for their ability to regulate l-carnitine uptake. All compounds tested significantly inhibited l-carnitine uptake. Inhibition by caffeine was not dantrolene (10 μM) sensitive despite dantrolene inhibiting caffeine-mediated calcium release. Saturation curve analysis suggested that caffeine did not competitively inhibit l-carnitine transport. To assess the potential role of AMPK in this process, we assessed the ability of the AMPK inhibitor Compound C (10 μM) to rescue the effect of caffeine. Compound C offered a partial rescue of l-carnitine uptake with 0.5 mM caffeine, suggesting that AMPK may play a role in the inhibitory effects of caffeine. However, caffeine likely inhibits l-carnitine uptake by alternative mechanisms independently of calcium release. PKA activation or direct interference with transporter function may play a role.
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Affiliation(s)
- Andy Shaw
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Stewart Jeromson
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Kenneth R Watterson
- Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; and
| | - John D Pediani
- Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; and
| | - Iain J Gallagher
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Tim Whalley
- Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Gillian Dreczkowski
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Naomi Brooks
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Stuart D Galloway
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - D Lee Hamilton
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom;
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Sung D, Kim S, Kim J, An H, So WY. Role of l-carnitine in sports performance: Focus on ergogenic aid and antioxidant. Sci Sports 2016. [DOI: 10.1016/j.scispo.2016.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Murton AJ, Maddocks M, Stephens FB, Marimuthu K, England R, Wilcock A. Consequences of Late-Stage Non-Small-Cell Lung Cancer Cachexia on Muscle Metabolic Processes. Clin Lung Cancer 2016; 18:e1-e11. [PMID: 27461772 DOI: 10.1016/j.cllc.2016.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/07/2016] [Accepted: 06/13/2016] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The loss of muscle is common in patients with advanced non-small-cell lung cancer (NSCLC) and contributes to the high morbidity and mortality of this group. The exact mechanisms behind the muscle loss are unclear. PATIENTS AND METHODS To investigate this, 4 patients with stage IV NSCLC who met the clinical definitions for sarcopenia and cachexia were recruited, along with 4 age-matched healthy volunteers. After an overnight fast, biopsy specimens were obtained from the vastus lateralis, and the key components associated with inflammation and the control of muscle protein, carbohydrate, and fat metabolism were assessed. RESULTS Compared with the healthy volunteers, significant increases in mRNA levels for interleukin-6 and NF-κB signaling and lower intramyocellular lipid content in slow-twitch fibers were observed in NSCLC patients. Although a significant decrease in phosphorylation of the mechanistic target of rapamycin (mTOR) signaling protein 4E-BP1 (Ser65) was observed, along with a trend toward reduced p70 S6K (Thr389) phosphorylation (P = .06), no difference was found between groups for the mRNA levels of MAFbx (muscle atrophy F box) and MuRF1 (muscle ring finger protein 1), chymotrypsin-like activity of the proteasome, or protein levels of multiple proteasome subunits. Moreover, despite decreases in intramyocellular lipid content, no robust changes in mRNA levels for key proteins involved in insulin signaling, glycolysis, oxidative metabolism, or fat metabolism were observed. CONCLUSION These findings suggest that examining the contribution of suppressed mTOR signaling in the loss of muscle mass in late-stage NSCLC patients is warranted and reinforces our need to understand the potential contribution of impaired fat metabolism and muscle protein synthesis in the etiology of cancer cachexia.
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Affiliation(s)
- Andrew J Murton
- Division of Nutritional Sciences, School of Biosciences, The University of Nottingham, Loughborough, United Kingdom; MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom.
| | - Matthew Maddocks
- Department of Palliative Medicine, The University of Nottingham, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom; King's College London, Cicely Saunders Institute, London, United Kingdom
| | - Francis B Stephens
- MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Kanagaraj Marimuthu
- MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Ruth England
- Department of Palliative Medicine, The University of Nottingham, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Andrew Wilcock
- Department of Palliative Medicine, The University of Nottingham, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
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Cheung WW, Cherqui S, Ding W, Esparza M, Zhou P, Shao J, Lieber RL, Mak RH. Muscle wasting and adipose tissue browning in infantile nephropathic cystinosis. J Cachexia Sarcopenia Muscle 2016; 7:152-64. [PMID: 27493869 PMCID: PMC4864942 DOI: 10.1002/jcsm.12056] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 04/21/2015] [Accepted: 06/03/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Muscle wasting is a common complication in patients with infantile nephropathic cystinosis, but its mechanism and association with energy metabolism is not known. We define the metabolic phenotype in Ctns(-/-) mice, an established murine model of infantile nephropathic cystinosis, with focus on muscle wasting and energy homeostasis. METHODS Male Ctns(-/-) mice and wild-type (WT) controls were studied at 1, 4, 9, and 12 months of age. As Ctns(-/-) mice started to develop chronic kidney disease (CKD) at 9 months of age, 9- and 12-month-old Ctns(-/-) mice were also compared with age-matched WT mice with CKD. Serum and urine chemistry and energy homeostasis parameters were measured. Skeletal muscle histomorphometry and in vivo muscle function were measured. We studied expression of genes involved in muscle mass regulation, thermogenesis, energy metabolism, adipogenesis, and adipose tissue browning in Ctns(-/-) mice. RESULTS Ctns(-/-) mice showed loss of weight and lean mass and increased energy expenditure. Ctns(-/-) mice exhibited abnormal energy homeostasis before the onset of their CKD. Food intake in Ctns(-/-) mice was comparable with age-matched WT controls. However, significantly lower total body mass starting at 1 month of age and increased energy expenditure at 4 months of age preceded the onset of CKD at 9 months of age in Ctns(-/-) mice. Muscle accept content in 1- and 4-month-old Ctns(-/-) mice was significantly lower than that in age-matched WT controls. At 12 months of age, muscle fibre area and in vivo muscle strength was reduced in Ctns(-/-) mice than that in WT or CKD controls. Muscle wasting in Ctns(-/-) mice was associated with inhibition of myogenesis, activation of muscle proteolysis pathways, and overexpression of pro-inflammatory cytokines. Increased energy expenditure was associated with elevation of thermogenesis in skeletal muscle and adipose tissues. The development of beige adipocytes in Ctns(-/-) mice is a novel finding. Expression of beige adipose cell surface markers (CD137, Tmem26, and Tbx1) and uncoupling protein-1, which is a brown adipose tissue marker, was observed in inguinal white adipose tissue of Ctns(-/-) mice. Expression of key molecules implicated in the pathogenesis of adipose tissue browning (Cox2, cytochrome c oxidase subunit II; PGF2α, prostaglandin F2α; IL-1α, interleukin 1α; IL-6, interleukin 6; TNF-α, tumor necrosis factor α) was significantly increased in inguinal white adipose tissue of Ctns(-/-) mice than that in WT controls. CONCLUSION This study describes a mouse model of nephropathic cystinosis presenting with profound muscle wasting. The mechanism for hypermetabolism in Ctns(-/-) mice may involve up-regulation of thermogenesis pathways in skeletal muscle and adipose tissues. This study demonstrates, for the first time, the development of beige adipocytes in Ctns(-/-) mice. Understanding the underlying mechanisms of adipose tissue browning in cystinosis may lead to novel therapy.
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Affiliation(s)
- Wai W Cheung
- Department of Pediatrics University of California San Diego CA USA
| | | | - Wei Ding
- Department of Pediatrics University of California San Diego CA USA; Division of Nephrology, The 5th People's Hospital of Shanghai Fudan University Shanghai China
| | - Mary Esparza
- Department of Orthopedic Surgery University of California San Diego CA USA
| | - Ping Zhou
- Department of Pediatrics University of California San Diego CA USA; Department of Pediatrics The 2nd Hospital of Harbin Medical University Harbin China
| | - Jianhua Shao
- Department of Pediatrics University of California San Diego CA USA
| | - Richard L Lieber
- Department of Orthopedic Surgery University of California San Diego CA USA; Rehabilitation Institute of Chicago Chicago
| | - Robert H Mak
- Department of Pediatrics University of California San Diego CA USA
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Chee C, Shannon CE, Burns A, Selby AL, Wilkinson D, Smith K, Greenhaff PL, Stephens FB. Relative Contribution of Intramyocellular Lipid to Whole-Body Fat Oxidation Is Reduced With Age but Subsarcolemmal Lipid Accumulation and Insulin Resistance Are Only Associated With Overweight Individuals. Diabetes 2016; 65:840-50. [PMID: 26740597 PMCID: PMC4894456 DOI: 10.2337/db15-1383] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/28/2015] [Indexed: 12/22/2022]
Abstract
Insulin resistance is closely related to intramyocellular lipid (IMCL) accumulation, and both are associated with increasing age. It remains to be determined to what extent perturbations in IMCL metabolism are related to the aging process per se. On two separate occasions, whole-body and muscle insulin sensitivity (euglycemic-hyperinsulinemic clamp with 2-deoxyglucose) and fat utilization during 1 h of exercise at 50% VO2max ([U-(13)C]palmitate infusion combined with electron microscopy of IMCL) were determined in young lean (YL), old lean (OL), and old overweight (OO) males. OL displayed IMCL content and insulin sensitivity comparable with those in YL, whereas OO were markedly insulin resistant and had more than twofold greater IMCL in the subsarcolemmal (SSL) region. Indeed, whereas the plasma free fatty acid Ra and Rd were twice those of YL in both OL and OO, SSL area only increased during exercise in OO. Thus, skeletal muscle insulin resistance and lipid accumulation often observed in older individuals are likely due to lifestyle factors rather than inherent aging of skeletal muscle as usually reported. However, age per se appears to cause exacerbated adipose tissue lipolysis, suggesting that strategies to reduce muscle lipid delivery and improve adipose tissue function may be warranted in older overweight individuals.
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Affiliation(s)
- Carolyn Chee
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham, Nottingham, U.K
| | - Chris E Shannon
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham, Nottingham, U.K
| | - Aisling Burns
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham, Nottingham, U.K
| | - Anna L Selby
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Medicine, The University of Nottingham, Nottingham, U.K
| | - Daniel Wilkinson
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Medicine, The University of Nottingham, Nottingham, U.K
| | - Kenneth Smith
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Medicine, The University of Nottingham, Nottingham, U.K
| | - Paul L Greenhaff
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham, Nottingham, U.K
| | - Francis B Stephens
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham, Nottingham, U.K.
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Shannon CE, Nixon AV, Greenhaff PL, Stephens FB. Protein ingestion acutely inhibits insulin-stimulated muscle carnitine uptake in healthy young men. Am J Clin Nutr 2016; 103:276-82. [PMID: 26675771 PMCID: PMC4756606 DOI: 10.3945/ajcn.115.119826] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/26/2015] [Indexed: 10/22/2022] Open
Abstract
BACKGROUND Increasing skeletal muscle carnitine content represents an appealing intervention in conditions of perturbed lipid metabolism such as obesity and type 2 diabetes but requires chronic L-carnitine feeding on a daily basis in a high-carbohydrate beverage. OBJECTIVE We investigated whether whey protein ingestion could reduce the carbohydrate load required to stimulate insulin-mediated muscle carnitine accretion. DESIGN Seven healthy men [mean ± SD age: 24 ± 5 y; body mass index (in kg/m(2)): 23 ± 3] ingested 80 g carbohydrate, 40 g carbohydrate + 40 g protein, or control (flavored water) beverages 60 min after the ingestion of 4.5 g L-carnitine tartrate (3 g L-carnitine; 0.1% (2)[H]3-L-carnitine). Serum insulin concentration, net forearm carnitine balance (NCB; arterialized-venous and venous plasma carnitine difference × brachial artery flow), and carnitine disappearance (Rd) and appearance (Ra) rates were determined at 20-min intervals for 180 min. RESULTS Serum insulin and plasma flow areas under the curve (AUCs) were similarly elevated by carbohydrate [4.5 ± 0.8 U/L · min (P < 0.01) and 0.5 ± 0.6 L (P < 0.05), respectively] and carbohydrate+protein [3.8 ± 0.6 U/L · min (P < 0.01) and 0.4 ± 0.6 L (P = 0.05), respectively] consumption, respectively, compared with the control visit (0.04 ± 0.1 U/L · min and -0.5 ± 0.2 L). Plasma carnitine AUC was greater after carbohydrate+protein consumption (3.5 ± 0.5 mmol/L · min) than after control and carbohydrate visits [2.1 ± 0.2 mmol/L · min (P < 0.05) and 1.9 ± 0.3 mmol/L · min (P < 0.01), respectively]. NCB AUC with carbohydrate (4.1 ± 3.1 μmol) was greater than during control and carbohydrate-protein visits (-8.6 ± 3.0 and -14.6 ± 6.4 μmol, respectively; P < 0.05), as was Rd AUC after carbohydrate (35.7 ± 25.2 μmol) compared with control and carbohydrate consumption [19.7 ± 15.5 μmol (P = 0.07) and 14.8 ± 9.6 μmol (P < 0.05), respectively]. CONCLUSIONS The insulin-mediated increase in forearm carnitine balance with carbohydrate consumption was acutely blunted by a carbohydrate+protein beverage, which suggests that carbohydrate+protein could inhibit chronic muscle carnitine accumulation.
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Affiliation(s)
- Chris E Shannon
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Aline V Nixon
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Paul L Greenhaff
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Francis B Stephens
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
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Ashmore T, Roberts LD, Morash AJ, Kotwica AO, Finnerty J, West JA, Murfitt SA, Fernandez BO, Branco C, Cowburn AS, Clarke K, Johnson RS, Feelisch M, Griffin JL, Murray AJ. Nitrate enhances skeletal muscle fatty acid oxidation via a nitric oxide-cGMP-PPAR-mediated mechanism. BMC Biol 2015; 13:110. [PMID: 26694920 PMCID: PMC4688964 DOI: 10.1186/s12915-015-0221-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/10/2015] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Insulin sensitivity in skeletal muscle is associated with metabolic flexibility, including a high capacity to increase fatty acid (FA) oxidation in response to increased lipid supply. Lipid overload, however, can result in incomplete FA oxidation and accumulation of potentially harmful intermediates where mitochondrial tricarboxylic acid cycle capacity cannot keep pace with rates of β-oxidation. Enhancement of muscle FA oxidation in combination with mitochondrial biogenesis is therefore emerging as a strategy to treat metabolic disease. Dietary inorganic nitrate was recently shown to reverse aspects of the metabolic syndrome in rodents by as yet incompletely defined mechanisms. RESULTS Herein, we report that nitrate enhances skeletal muscle FA oxidation in rodents in a dose-dependent manner. We show that nitrate induces FA oxidation through a soluble guanylate cyclase (sGC)/cGMP-mediated PPARβ/δ- and PPARα-dependent mechanism. Enhanced PPARβ/δ and PPARα expression and DNA binding induces expression of FA oxidation enzymes, increasing muscle carnitine and lowering tissue malonyl-CoA concentrations, thereby supporting intra-mitochondrial pathways of FA oxidation and enhancing mitochondrial respiration. At higher doses, nitrate induces mitochondrial biogenesis, further increasing FA oxidation and lowering long-chain FA concentrations. Meanwhile, nitrate did not affect mitochondrial FA oxidation in PPARα(-/-) mice. In C2C12 myotubes, nitrate increased expression of the PPARα targets Cpt1b, Acadl, Hadh and Ucp3, and enhanced oxidative phosphorylation rates with palmitoyl-carnitine; however, these changes in gene expression and respiration were prevented by inhibition of either sGC or protein kinase G. Elevation of cGMP, via the inhibition of phosphodiesterase 5 by sildenafil, also increased expression of Cpt1b, Acadl and Ucp3, as well as CPT1B protein levels, and further enhanced the effect of nitrate supplementation. CONCLUSIONS Nitrate may therefore be effective in the treatment of metabolic disease by inducing FA oxidation in muscle.
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Affiliation(s)
- Tom Ashmore
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Lee D Roberts
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- MRC-Human Nutrition Research, University of Cambridge, Cambridge, UK
| | - Andrea J Morash
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Aleksandra O Kotwica
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - John Finnerty
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - James A West
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Steven A Murfitt
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Bernadette O Fernandez
- Faculty of Medicine, Clinical & Experimental Sciences, University of Southampton, Southampton, UK
| | - Cristina Branco
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Andrew S Cowburn
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Kieran Clarke
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, UK
| | - Randall S Johnson
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Martin Feelisch
- Faculty of Medicine, Clinical & Experimental Sciences, University of Southampton, Southampton, UK
| | - Julian L Griffin
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- MRC-Human Nutrition Research, University of Cambridge, Cambridge, UK
| | - Andrew J Murray
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
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Kim JH, Pan JH, Lee ES, Kim YJ. l -Carnitine enhances exercise endurance capacity by promoting muscle oxidative metabolism in mice. Biochem Biophys Res Commun 2015; 464:568-73. [DOI: 10.1016/j.bbrc.2015.07.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 11/15/2022]
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Panchal SK, Poudyal H, Ward LC, Waanders J, Brown L. Modulation of tissue fatty acids by L-carnitine attenuates metabolic syndrome in diet-induced obese rats. Food Funct 2015; 6:2496-506. [PMID: 26190559 DOI: 10.1039/c5fo00480b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Obesity and dyslipidaemia are metabolic defects resulting from impaired lipid metabolism. These impairments are associated with the development of cardiovascular disease and non-alcoholic fatty liver disease. Correcting the defects in lipid metabolism may attenuate obesity and dyslipidaemia, and reduce cardiovascular risk and liver damage. L-Carnitine supplementation was used in this study to enhance fatty acid oxidation so as to ameliorate diet-induced disturbances in lipid metabolism. Male Wistar rats (8-9 weeks old) were fed with either corn starch or high-carbohydrate, high-fat diets for 16 weeks. Separate groups were supplemented with L-carnitine (1.2% in food) on either diet for the last 8 weeks of the protocol. High-carbohydrate, high-fat diet-fed rats showed central obesity, dyslipidaemia, hypertension, impaired glucose tolerance, hyperinsulinaemia, cardiovascular remodelling and non-alcoholic fatty liver disease. L-Carnitine supplementation attenuated these high-carbohydrate, high-fat diet-induced changes, together with modifications in lipid metabolism including the inhibition of stearoyl-CoA desaturase-1 activity, reduced storage of short-chain monounsaturated fatty acids in the tissues with decreased linoleic acid content and trans fatty acids stored in retroperitoneal fat. Thus, L-carnitine supplementation attenuated the signs of metabolic syndrome through inhibition of stearoyl-CoA desaturase-1 activity, preferential β-oxidation of some fatty acids and increased storage of saturated fatty acids and relatively inert oleic acid in the tissues.
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Affiliation(s)
- Sunil K Panchal
- Institute for Agriculture and the Environment, University of Southern Queensland, Toowoomba, QLD 4350, Australia.
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Nag S, Khan MA, Samuel P, Ali Q, Hussain T. Chronic angiotensin AT2R activation prevents high-fat diet-induced adiposity and obesity in female mice independent of estrogen. Metabolism 2015; 64:814-25. [PMID: 25869303 PMCID: PMC4437825 DOI: 10.1016/j.metabol.2015.01.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/12/2014] [Accepted: 01/05/2015] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Obesity is a known risk factor for various metabolic disorders and cardiovascular diseases. Recently we demonstrated that female angiotensin AT2 receptor (AT2R) knockout mice on high-fat diet (HFD) had higher body weight and adiposity with a parallel reduction in estrogen (17,β-estradiol/E2). The present study investigated whether the anti-adiposity effects of the AT2R are estrogen-dependent in female mice. METHODS Female C57BL/6 ovary-intact (Ovi) mice were treated with an AT2R agonist (C21, 0.3 mg/kg, daily i.p.). Ovariectomized (Ovx) mice, supplemented with E2 (5 μg/day, pellets implanted subcutaneously), were treated with an AT2R agonist (C21, 0.3 mg/kg, daily i.p.) or vehicle. After 4-days of pre-treatment with C21, Ovi and Ovx mice were placed on either normal diet (ND) or HFD while the C21 treatment continued for the next 10 days. For a long-term study, Ovi mice were placed on HFD and treated with C21 for 12 weeks. RESULTS Ovi mice fed the HFD had increased parametrial white adipose tissue (pWAT) weight, plasma free fatty acid and triglycerides compared to Ovi mice on ND. Ovariectomy alone caused similar changes in these parameters which were further increased by HFD-feeding. C21 treatment attenuated these HFD-induced changes in Ovi as well as Ovx mice. HFD also, increased the liver/body-weight ratio and decreased the liver expression of the β-oxidation enzyme, carnitine palmitoyltransferase 1 (CPT1-A). C21 treatment attenuated these changes as well. The long-term C21 treatment of Ovi mice lowered the HFD-induced body weight gain, increase in pWAT weight, parametrial adipocyte size and hyperinsulinemia induced by HFD. Finally, HFD drastically reduced urinary estrogen and the beneficial metabolic changes in response to C21-treatment occurred without significantly increasing urinary estrogen. CONCLUSION We suggest that the pharmacological activation of AT2R by the agonist C21 reduces adiposity and body weight gain independent of estrogen in female mice. Improvement in fatty acid metabolism is a potential mechanism by which the AT2R exerts anti-adiposity effects.
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Affiliation(s)
- Sourashish Nag
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204
| | - Mohammad Azhar Khan
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204
| | - Preethi Samuel
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204
| | - Quaisar Ali
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204
| | - Tahir Hussain
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204.
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Performance Enhancing Diets and the PRISE Protocol to Optimize Athletic Performance. J Nutr Metab 2015; 2015:715859. [PMID: 25949823 PMCID: PMC4408745 DOI: 10.1155/2015/715859] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 03/03/2015] [Indexed: 12/14/2022] Open
Abstract
The training regimens of modern-day athletes have evolved from the sole emphasis on a single fitness component (e.g., endurance athlete or resistance/strength athlete) to an integrative, multimode approach encompassing all four of the major fitness components: resistance (R), interval sprints (I), stretching (S), and endurance (E) training. Athletes rarely, if ever, focus their training on only one mode of exercise but instead routinely engage in a multimode training program. In addition, timed-daily protein (P) intake has become a hallmark for all athletes. Recent studies, including from our laboratory, have validated the effectiveness of this multimode paradigm (RISE) and protein-feeding regimen, which we have collectively termed PRISE. Unfortunately, sports nutrition recommendations and guidelines have lagged behind the PRISE integrative nutrition and training model and therefore limit an athletes' ability to succeed. Thus, it is the purpose of this review to provide a clearly defined roadmap linking specific performance enhancing diets (PEDs) with each PRISE component to facilitate optimal nourishment and ultimately optimal athletic performance.
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Mallinson JE, Marimuthu K, Murton A, Selby A, Smith K, Constantin-Teodosiu D, Rennie MJ, Greenhaff PL. Statin myalgia is not associated with reduced muscle strength, mass or protein turnover in older male volunteers, but is allied with a slowing of time to peak power output, insulin resistance and differential muscle mRNA expression. J Physiol 2015; 593:1239-57. [PMID: 25620655 PMCID: PMC4358682 DOI: 10.1113/jphysiol.2014.285577] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 12/19/2014] [Indexed: 12/13/2022] Open
Abstract
Key points Statins cause muscle‐specific side effects, most commonly muscle aches/weakness (myalgia), particularly in older people. Furthermore, evidence has linked statin use to increased risk of type 2 diabetes. However, the mechanisms involved are unknown. This is the first study to measure muscle protein turnover rates and insulin sensitivity in statin myalgic volunteers and age‐matched, non‐statin users under controlled fasting and fed conditions using gold standard methods. We demonstrate in older people that chronic statin myalgia is not associated with deficits in muscle strength and lean mass or the dysregulation of muscle protein turnover compared to non‐statin users. Furthermore, there were no between‐group differences in blood or muscle inflammatory markers. Statin users did, however, show blunting of muscle power output at the onset of dynamic exercise, increased abdominal adiposity, whole body and leg insulin resistance, and clear differential expression of muscle genes linked to mitochondrial dysfunction and apoptosis, which warrant further investigation.
Abstract Statins are associated with muscle myalgia and myopathy, which probably reduce habitual physical activity. This is particularly relevant to older people who are less active, sarcopaenic and at increased risk of statin myalgia. We hypothesised that statin myalgia would be allied to impaired strength and work capacity in older people, and determined whether differences aligned with divergences in lean mass, protein turnover, insulin sensitivity and the molecular regulation of these processes. Knee extensor strength and work output during 30 maximal isokinetic contractions were assessed in healthy male volunteers, nine with no statin use (control 70.4 ± 0.7 years) and nine with statin myalgia (71.5 ± 0.9 years). Whole body and leg glucose disposal, muscle myofibrillar protein synthesis (MPS) and leg protein breakdown (LPB) were measured during fasting (≈5 mU l−1 insulin) and fed (≈40 mU l−1 insulin + hyperaminoacidaemia) euglyceamic clamps. Muscle biopsies were taken before and after each clamp. Lean mass, MPS, LPB and strength were not different but work output during the initial three isokinetic contractions was 19% lower (P < 0.05) in statin myalgic subjects due to a delay in time to reach peak power output. Statin myalgic subjects had reduced whole body (P = 0.05) and leg (P < 0.01) glucose disposal, greater abdominal adiposity (P < 0.05) and differential expression of 33 muscle mRNAs (5% false discovery rate (FDR)), six of which, linked to mitochondrial dysfunction and apoptosis, increased at 1% FDR. Statin myalgia was associated with impaired muscle function, increased abdominal adiposity, whole body and leg insulin resistance, and evidence of mitochondrial dysfunction and apoptosis.
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Affiliation(s)
- Joanne E Mallinson
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, NG7 2UH, UK
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Novakova K, Kummer O, Bouitbir J, Stoffel SD, Hoerler-Koerner U, Bodmer M, Roberts P, Urwyler A, Ehrsam R, Krähenbühl S. Effect of l-carnitine supplementation on the body carnitine pool, skeletal muscle energy metabolism and physical performance in male vegetarians. Eur J Nutr 2015; 55:207-17. [DOI: 10.1007/s00394-015-0838-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Accepted: 01/13/2015] [Indexed: 11/30/2022]
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Rossow HA, Calvert CC. Computer modeling of obesity links theoretical energetic measures with experimental measures of fuel use for lean and obese men. J Nutr 2014; 144:1650-7. [PMID: 25122649 DOI: 10.3945/jn.114.192351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The goal of this research was to use a computational model of human metabolism to predict energy metabolism for lean and obese men. The model is composed of 6 state variables representing amino acids, muscle protein, visceral protein, glucose, triglycerides, and fatty acids (FAs). Differential equations represent carbohydrate, amino acid, and FA uptake and output by tissues based on ATP creation and use for both lean and obese men. Model parameterization is based on data from previous studies. Results from sensitivity analyses indicate that model predictions of resting energy expenditure (REE) and respiratory quotient (RQ) are dependent on FA and glucose oxidation rates with the highest sensitivity coefficients (0.6, 0.8 and 0.43, 0.15, respectively, for lean and obese models). Metabolizable energy (ME) is influenced by ingested energy intake with a sensitivity coefficient of 0.98, and a phosphate-to-oxygen ratio by FA oxidation rate and amino acid oxidation rate (0.32, 0.24 and 0.55, 0.65 for lean and obese models, respectively). Simulations of previously published studies showed that the model is able to predict ME ranging from 6.6 to 9.3 with 0% differences between published and model values, and RQ ranging from 0.79 to 0.86 with 1% differences between published and model values. REEs >7 MJ/d are predicted with 6% differences between published and model values. Glucose oxidation increases by ∼0.59 mol/d, RQ increases by 0.03, REE increases by 2 MJ/d, and heat production increases by 1.8 MJ/d in the obese model compared with lean model simulations. Increased FA oxidation results in higher changes in RQ and lower relative changes in REE. These results suggest that because fat mass is directly related to REE and rate of FA oxidation, body fat content could be used as a predictor of RQ.
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Affiliation(s)
- Heidi A Rossow
- Population Health and Reproduction, School of Veterinary Medicine, and
| | - C Chris Calvert
- Department of Animal Science, University of California at Davis, Davis, CA
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Shang R, Sun Z, Li H. Effective dosing of L-carnitine in the secondary prevention of cardiovascular disease: a systematic review and meta-analysis. BMC Cardiovasc Disord 2014; 14:88. [PMID: 25044037 PMCID: PMC4223629 DOI: 10.1186/1471-2261-14-88] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 07/14/2014] [Indexed: 11/10/2022] Open
Abstract
Background L-carnitine supplementation has been associated with a significant reduction in all-cause mortality, ventricular arrhythmia, and angina in the setting of acute myocardial infarction (MI). However, on account of strict homeostatic regulation of plasma L-carnitine concentrations, higher doses of L-carnitine supplementation may not provide additional therapeutic benefits. This study aims to evaluate the effects of various oral maintenance dosages of L-carnitine on all-cause mortality and cardiovascular morbidities in the setting of acute MI. Methods After a systematic review of several major electronic databases (PubMed, EMBASE, and the Cochrane Library) up to November 2013, a meta-analysis of five controlled trials (n = 3108) was conducted to determine the effects of L-carnitine on all-cause mortality and cardiovascular morbidities in the setting of acute MI. Results The interaction test yielded no significant differences between the effects of the four daily oral maintenance dosages of L-carnitine (i.e., 2 g, 3 g, 4 g, and 6 g) on all-cause mortality (risk ratio [RR] = 0.77, 95% CI [0.57-1.03], P = 0.08) with a statistically insignificant trend favoring the 3 g dose (RR = 0.48) over the lower 2 g dose (RR = 0.62), which was favored over the higher 4 g and 6 g doses (RR = 0.78, 0.78). There was no significant differences between the effects of the daily oral maintenance dosages of 2 g and 6 g on heart failure (RR = 0.53, 95% CI [0.25-1.13], P = 0.10), unstable angina (RR = 0.90, 95% CI [0.51-1.58], P = 0.71), or myocardial reinfarction (RR = 0.74, 95% CI [0.30-1.80], P = 0.50). Conclusions There appears to be no significant marginal benefit in terms of all-cause mortality, heart failure, unstable angina, or myocardial reinfarction in the setting of acute MI for oral L-carnitine maintenance doses of greater or less than 3 g per day.
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Affiliation(s)
- Ruiping Shang
- Department of Cardiology, Daqing General Hospital Group, Oilfield General Hospital, No, 9 Zhongkang Road, Daqing City 163001, Heilong Jiang Province, China.
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