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McCarthy DG, Bostad W, Powley FJ, Little JP, Richards DL, Gibala MJ. Increased cardiorespiratory stress during submaximal cycling after ketone monoester ingestion in endurance-trained adults. Appl Physiol Nutr Metab 2021; 46:986-993. [PMID: 33646860 DOI: 10.1139/apnm-2020-0999] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
There is growing interest in the effect of exogenous ketone body supplementation on exercise responses and performance. The limited studies to date have yielded equivocal data, likely due in part to differences in dosing strategy, increase in blood ketones, and participant training status. Using a randomized, double-blind, counterbalanced design, we examined the effect of ingesting a ketone monoester (KE) supplement (600 mg/kg body mass) or flavour-matched placebo in endurance-trained adults (n = 10 males, n = 9 females; V̇O2peak = 57 ± 8 mL/kg/min). Participants performed a 30-min cycling bout at ventilatory threshold intensity (71 ± 3% V̇O2peak), followed 15 min later by a 3 kJ/kg body mass time-trial. KE versus placebo ingestion increased plasma β-hydroxybutyrate concentration before exercise (3.9 ± 1.0 vs 0.2 ± 0.3 mM, p < 0.0001, dz = 3.4), ventilation (77 ± 17 vs 71 ± 15 L/min, p < 0.0001, dz = 1.3) and heart rate (155 ± 11 vs 150 ± 11 beats/min, p < 0.001, dz = 1.2) during exercise, and rating of perceived exertion at the end of exercise (15.4 ± 1.6 vs 14.5 ± 1.2, p < 0.01, dz = 0.85). Plasma β-hydroxybutyrate concentration remained higher after KE vs placebo ingestion before the time-trial (3.5 ± 1.0 vs 0.3 ± 0.2 mM, p < 0.0001, dz = 3.1), but performance was not different (KE: 16:25 ± 2:50 vs placebo: 16:06 ± 2:40 min:s, p = 0.20; dz = 0.31). We conclude that acute ingestion of a relatively large KE bolus dose increased markers of cardiorespiratory stress during submaximal exercise in endurance-trained participants. Novelty: Limited studies have yielded equivocal data regarding exercise responses after acute ketone body supplementation. Using a randomized, double-blind, placebo-controlled, counterbalanced design, we found that ingestion of a large bolus dose of a commercial ketone monoester supplement increased markers of cardiorespiratory stress during cycling at ventilatory threshold intensity in endurance-trained adults.
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Affiliation(s)
- Devin G McCarthy
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - William Bostad
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Fiona J Powley
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Jonathan P Little
- School of Health and Exercise Sciences, The University of British Columbia Okanagan, Kelowna, BC, Canada
| | | | - Martin J Gibala
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
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2
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Klein DJ, Anthony TG, McKeever KH. Metabolomics in equine sport and exercise. J Anim Physiol Anim Nutr (Berl) 2020; 105:140-148. [PMID: 32511844 DOI: 10.1111/jpn.13384] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 04/15/2020] [Indexed: 01/27/2023]
Abstract
metabolomics is the high-throughput, multiparametric identification and classification of hundreds of low molecular weight metabolites in a biological sample. Ultimately, metabolites are the downstream readouts of cellular signalling, transcriptomic and proteomic changes that can provide a comprehensive view of tissue and organismal phenotype. The popularity of metabolomics in human sport and exercise has been gaining over the past decade and has provided important insights into the energetic demands and mechanistic underpinnings of exercise and training. To the contrary, metabolomics in the field of equine exercise physiology is lagging despite the horse's superior aerobic and muscular capabilities, as well as its prominence in competitive sport. As such, this narrative review aims to describe metabolomics, its routine implementation, the various analytical methods applied and the state of its use in the equine athlete. Sufficient attention will be paid to methodological considerations, as well as gaps in the equine literature, particularly with regard to the skeletal muscle metabolome. Finally, there will be a brief discussion of the future directions and barriers to metabolomics use in the athletic horse. A thorough understanding of the metabolomics changes that occur in the equine athlete with exercise will undoubtedly help to improve horse management and health across the lifespan.
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Affiliation(s)
- Dylan J Klein
- Department of Health and Exercise Science, Rowan University, Glassboro, New Jersey, USA
| | - Tracy G Anthony
- Department of Nutritional Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.,New Jersey Institute for Food, Nutrition and Health, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Kenneth H McKeever
- Rutgers Equine Science Center, Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA
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3
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Vigelsø A, Gram M, Dybboe R, Kuhlman AB, Prats C, Greenhaff PL, Constantin-Teodosiu D, Birk JB, Wojtaszewski JFP, Dela F, Helge JW. The effect of age and unilateral leg immobilization for 2 weeks on substrate utilization during moderate-intensity exercise in human skeletal muscle. J Physiol 2016; 594:2339-58. [PMID: 26801521 DOI: 10.1113/jp271712] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/15/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS This study aimed to provide molecular insight into the differential effects of age and physical inactivity on the regulation of substrate metabolism during moderate-intensity exercise. Using the arteriovenous balance technique, we studied the effect of immobilization of one leg for 2 weeks on leg substrate utilization in young and older men during two-legged dynamic knee-extensor moderate-intensity exercise, as well as changes in key proteins in muscle metabolism before and after exercise. Age and immobilization did not affect relative carbohydrate and fat utilization during exercise, but the older men had higher uptake of exogenous fatty acids, whereas the young men relied more on endogenous fatty acids during exercise. Using a combined whole-leg and molecular approach, we provide evidence that both age and physical inactivity result in intramuscular lipid accumulation, but this occurs only in part through the same mechanisms. ABSTRACT Age and inactivity have been associated with intramuscular triglyceride (IMTG) accumulation. Here, we attempt to disentangle these factors by studying the effect of 2 weeks of unilateral leg immobilization on substrate utilization across the legs during moderate-intensity exercise in young (n = 17; 23 ± 1 years old) and older men (n = 15; 68 ± 1 years old), while the contralateral leg served as the control. After immobilization, the participants performed two-legged isolated knee-extensor exercise at 20 ± 1 W (∼50% maximal work capacity) for 45 min with catheters inserted in the brachial artery and both femoral veins. Biopsy samples obtained from vastus lateralis muscles of both legs before and after exercise were used for analysis of substrates, protein content and enzyme activities. During exercise, leg substrate utilization (respiratory quotient) did not differ between groups or legs. Leg fatty acid uptake was greater in older than in young men, and although young men demonstrated net leg glycerol release during exercise, older men showed net glycerol uptake. At baseline, IMTG, muscle pyruvate dehydrogenase complex activity and the protein content of adipose triglyceride lipase, acetyl-CoA carboxylase 2 and AMP-activated protein kinase (AMPK)γ3 were higher in young than in older men. Furthermore, adipose triglyceride lipase, plasma membrane-associated fatty acid binding protein and AMPKγ3 subunit protein contents were lower and IMTG was higher in the immobilized than the contralateral leg in young and older men. Thus, immobilization and age did not affect substrate choice (respiratory quotient) during moderate exercise, but the whole-leg and molecular differences in fatty acid mobilization could explain the age- and immobilization-induced IMTG accumulation.
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Affiliation(s)
- A Vigelsø
- XLAB, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M Gram
- XLAB, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - R Dybboe
- XLAB, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.,Section of Molecular Physiology, The August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - A B Kuhlman
- XLAB, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - C Prats
- XLAB, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - P L Greenhaff
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, School of Life Sciences, The Medical School, University of Nottingham, Nottingham, UK
| | - D Constantin-Teodosiu
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, School of Life Sciences, The Medical School, University of Nottingham, Nottingham, UK
| | - J B Birk
- Section of Molecular Physiology, The August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - J F P Wojtaszewski
- Section of Molecular Physiology, The August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - F Dela
- XLAB, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - J W Helge
- XLAB, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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4
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Affiliation(s)
- Andreas Børsting Jordy
- Section of Molecular Physiology; August Krogh Centre; Department of Nutrition; Exercise and Sports (NEXS); University of Copenhagen Copenhagen Denmark
| | - Bente Kiens
- Section of Molecular Physiology; August Krogh Centre; Department of Nutrition; Exercise and Sports (NEXS); University of Copenhagen Copenhagen Denmark
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5
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Heemskerk MM, Dharuri HK, van den Berg SAA, Jónasdóttir HS, Kloos DP, Giera M, van Dijk KW, van Harmelen V. Prolonged niacin treatment leads to increased adipose tissue PUFA synthesis and anti-inflammatory lipid and oxylipin plasma profile. J Lipid Res 2014; 55:2532-40. [PMID: 25320342 DOI: 10.1194/jlr.m051938] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Prolonged niacin treatment elicits beneficial effects on the plasma lipid and lipoprotein profile that is associated with a protective CVD risk profile. Acute niacin treatment inhibits nonesterified fatty acid release from adipocytes and stimulates prostaglandin release from skin Langerhans cells, but the acute effects diminish upon prolonged treatment, while the beneficial effects remain. To gain insight in the prolonged effects of niacin on lipid metabolism in adipocytes, we used a mouse model with a human-like lipoprotein metabolism and drug response [female APOE*3-Leiden.CETP (apoE3 Leiden cholesteryl ester transfer protein) mice] treated with and without niacin for 15 weeks. The gene expression profile of gonadal white adipose tissue (gWAT) from niacin-treated mice showed an upregulation of the "biosynthesis of unsaturated fatty acids" pathway, which was corroborated by quantitative PCR and analysis of the FA ratios in gWAT. Also, adipocytes from niacin-treated mice secreted more of the PUFA DHA ex vivo. This resulted in an increased DHA/arachidonic acid (AA) ratio in the adipocyte FA secretion profile and in plasma of niacin-treated mice. Interestingly, the DHA metabolite 19,20-dihydroxy docosapentaenoic acid (19,20-diHDPA) was increased in plasma of niacin-treated mice. Both an increased DHA/AA ratio and increased 19,20-diHDPA are indicative for an anti-inflammatory profile and may indirectly contribute to the atheroprotective lipid and lipoprotein profile associated with prolonged niacin treatment.
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Affiliation(s)
- Mattijs M Heemskerk
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Harish K Dharuri
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Sjoerd A A van den Berg
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Hulda S Jónasdóttir
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Dick-Paul Kloos
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Martin Giera
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Ko Willems van Dijk
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Vanessa van Harmelen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
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6
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Heemskerk MM, van den Berg SAA, Pronk ACM, van Klinken JB, Boon MR, Havekes LM, Rensen PCN, van Dijk KW, van Harmelen V. Long-term niacin treatment induces insulin resistance and adrenergic responsiveness in adipocytes by adaptive downregulation of phosphodiesterase 3B. Am J Physiol Endocrinol Metab 2014; 306:E808-13. [PMID: 24473440 PMCID: PMC3962609 DOI: 10.1152/ajpendo.00641.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The lipid-lowering effect of niacin has been attributed to the inhibition of cAMP production in adipocytes, thereby inhibiting intracellular lipolysis and release of nonesterified fatty acids (NEFA) to the circulation. However, long-term niacin treatment leads to a normalization of plasma NEFA levels and induces insulin resistance, for which the underlying mechanisms are poorly understood. The current study addressed the effects of long-term niacin treatment on insulin-mediated inhibition of adipocyte lipolysis and focused on the regulation of cAMP levels. APOE*3-Leiden.CETP transgenic mice treated with niacin for 15 wk were subjected to an insulin tolerance test and showed whole body insulin resistance. Similarly, adipocytes isolated from niacin-treated mice were insulin resistant and, interestingly, exhibited an increased response to cAMP stimulation by 8Br-cAMP, β1- and β2-adrenergic stimulation. Gene expression analysis of the insulin and β-adrenergic pathways in adipose tissue indicated that all genes were downregulated, including the gene encoding the cAMP-degrading enzyme phosphodiesterase 3B (PDE3B). In line with this, we showed that insulin induced a lower PDE3B response in adipocytes isolated from niacin-treated mice. Inhibiting PDE3B with cilostazol increased lipolytic responsiveness to cAMP stimulation in adipocytes. These data show that long-term niacin treatment leads to a downregulation of PDE3B in adipocytes, which could explain part of the observed insulin resistance and the increased responsiveness to cAMP stimulation.
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Affiliation(s)
- Mattijs M. Heemskerk
- 1Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands;
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
| | - Sjoerd A. A. van den Berg
- 1Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands;
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
| | - Amanda C. M. Pronk
- 1Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands;
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
| | - Jan-Bert van Klinken
- 1Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands;
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
| | - Mariëtte R. Boon
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
- 3Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands; and
| | - Louis M. Havekes
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
- 3Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands; and
- 4TNO Quality of Life, Leiden, The Netherlands
| | - Patrick C. N. Rensen
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
- 3Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands; and
| | - Ko Willems van Dijk
- 1Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands;
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
- 3Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands; and
| | - Vanessa van Harmelen
- 1Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands;
- 2Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands;
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Décombaz J, Grathwohl D, Pollien P, Schmitt JAJ, Borrani F, Lecoultre V. Effect of short-duration lipid supplementation on fat oxidation during exercise and cycling performance. Appl Physiol Nutr Metab 2013; 38:766-72. [PMID: 23980735 DOI: 10.1139/apnm-2012-0459] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of intramyocellular lipids (IMCLs) on endurance performance with high skeletal muscle glycogen availability remains unclear. Previous work has shown that a lipid-supplemented high-carbohydrate (CHO) diet increases IMCLs while permitting normal glycogen loading. The aim of this study was to assess the effect of fat supplementation on fat oxidation (Fox) and endurance performance. Twenty-two trained male cyclists performed 2 simulated time trials (TT) in a randomized crossover design. Subjects cycled at ∼53% maximal voluntary external power for 2 h and then followed 1 of 2 diets for 2.5 days: a high-CHO low-fat (HC) diet, consisting of CHO 7.4 g·kg(-1)·day(-1) and fat 0.5 g·kg(-1)·day(-1); or a high-CHO fat-supplemented (HCF) diet, which was a replication of the HC diet with ∼240 g surplus fat (30% saturation) distributed over the last 4 meals of the diet period. On trial morning, fasting blood was sampled and Fox was measured during an incremental exercise; a ∼1-h TT followed. Breath volatile compounds (VOCs) were measured at 3 time points. Mental fatigue, measured as reaction time, was evaluated during the TT. Plasma free fatty acid concentration was 50% lower after the HCF diet (p < 0.0001), and breath acetone was reduced (p < 0.05) "at rest". Fox peaked (∼0.35 g·kg(-1)) at ∼42% peak oxygen consumption, and was not influenced by diet. Performance was not significantly different between the HCF and HC diets (3369 ± 46 s vs 3398 ± 48 s; p = 0.39), nor were reaction times to the attention task and VOCs (p = NS for both). In conclusion, the short-term intake of a lipid supplement in combination with a glycogen-loading diet designed to boost intramyocellular lipids while avoiding fat adaptation did not alter substrate oxidation during exercise or 1-hour cycling performance.
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Affiliation(s)
- Jacques Décombaz
- Nestlé Research Center, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland.
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8
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Ringseis R, Rosenbaum S, Gessner DK, Herges L, Kubens JF, Mooren FC, Krüger K, Eder K. Supplementing obese Zucker rats with niacin induces the transition of glycolytic to oxidative skeletal muscle fibers. J Nutr 2013; 143:125-31. [PMID: 23256146 DOI: 10.3945/jn.112.164038] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the present study, we tested the hypothesis that niacin increases the oxidative capacity of muscle by increasing the oxidative type I muscle fiber content. Twenty-four obese Zucker rats were assigned to 2 groups of 12 rats that were fed either a control diet (O group) or a diet supplemented with 750 mg/kg diet niacin (O+N group) for 4 wk. In addition, one group of lean rats (L group) was included in the experiment and fed the control diet for 4 wk. Plasma and liver concentrations of TG were markedly greater in obese groups than in the L group but markedly lower in the O+N group than in the O group (P < 0.05). Rats of the O+N group had a higher percentage of oxidative type I fibers and higher mRNA levels of genes encoding regulators of muscle fiber composition (Ppard, Ppargc1a, Ppargc1b), angiogenic factors (Vegfa, Vegfb), and genes involved in fatty acid utilization (Cpt1b, Slc25a20, Slc22a4, Slc22a5, Slc27a1) and oxidative phosphorylation (Cox4i1, Cox6a2) and a higher activity of the mitochondrial oxidative enzyme succinate dehydrogenase in muscle than rats of the O and L groups (P < 0.05). These niacin-induced changes in muscle metabolic phenotype are indicative of an increased capacity of muscle for oxidative utilization of fatty acids and are likely mediated by the upregulation of Ppard, Ppargc1a, and Ppargc1b, which are key regulators of muscle fiber composition, mitochondrial biogenesis, angiogenesis, and genes involved in fatty acid catabolism and oxidative phosphorylation. The increased utilization of fatty acids by muscle might contribute to the strong TG-lowering effect of niacin treatment.
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Affiliation(s)
- Robert Ringseis
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University, Giessen,Germany
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9
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Djoussé L, Driver JA, Gaziano JM, Buring JE, Lee IM. Association between modifiable lifestyle factors and residual lifetime risk of diabetes. Nutr Metab Cardiovasc Dis 2013; 23:17-22. [PMID: 21982361 PMCID: PMC3274624 DOI: 10.1016/j.numecd.2011.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 08/02/2011] [Accepted: 08/03/2011] [Indexed: 02/07/2023]
Abstract
BACKGROUND AND AIMS While clinical trials have reported beneficial effects of diet, exercise, and weight loss on incident diabetes in subjects with obesity or impaired glucose tolerance, little is known about the incremental benefit of not smoking and moderate drinking on diabetes risk. We sought to examine the association between modifiable lifestyle factors and residual lifetime risk of diabetes. METHODS AND RESULTS Prospective cohorts involving 20,915 men (1982-2008) and 36,594 women (1992-2008). Modifiable lifestyle factors and adiposity were ascertained at baseline in each cohort and incident diabetes was ascertained during follow up. The mean age at baseline was 53.5 y in men and 54.6 y in women. During an average follow up of 22.6 y in men and 13.0 y in women, 2096 men and 2390 women developed diabetes. At age 45 y, the residual lifetime risk of diabetes (95% CI) for men with 0, 1, 2, 3, and 4 + healthy lifestyle factors was 30.5 (27.3-33.7); 21.5 (19.9-23.0); 15.1 (13.9-16.3); 10.3 (9.1-11.5); and 7.3 (5.7-8.9) percent; respectively. Corresponding values for women were 31.4 (28.3-34.5); 24.1 (21.8-26.5); 14.2 (12.7-15.7); 11.6 (9.7-13.5); and 6.4 (4.2-8.6) percent, respectively. CONCLUSIONS These data show an inverse and graded relation between desirable lifestyle factors and residual lifetime risk of diabetes in men and women. Not smoking and moderate drinking may have additional benefits when added to exercise, weight control, and diet.
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Affiliation(s)
- L Djoussé
- Divisions of Aging, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02120, USA.
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10
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Kang I, Kim SW, Youn JH. Effects of nicotinic acid on gene expression: potential mechanisms and implications for wanted and unwanted effects of the lipid-lowering drug. J Clin Endocrinol Metab 2011; 96:3048-55. [PMID: 21816780 PMCID: PMC3200242 DOI: 10.1210/jc.2011-1104] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
CONTEXT Nicotinic acid (NA), or niacin, lowers circulating levels of lipids, including triglycerides, very low-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol. The lipid-lowering effects have been attributed to its effect to inhibit lipolysis in adipocytes and thus lower plasma free fatty acid (FFA) level. However, evidence accumulates that the FFA-lowering effect may account for only a fraction of NA effects on plasma lipids, and other mechanisms may be involved. Recent studies have reported NA effects on gene expression in various tissues in vivo and in cultured cells in vitro. EVIDENCE ACQUISITION We reviewed articles reporting NA effects on gene expression, identified by searching PubMed, focusing on potential underlying mechanisms and implications for unexplained NA effects. CONCLUSION The effects of NA on gene expression may be mediated directly via the NA receptor in the affected cells, indirectly via changes in circulating FFA or hormone levels induced by NA, or by activating the transcription factor FOXO1 in insulin-sensitive tissues. NA effects on gene expression provide new insights into previously unexplained NA effects, such as FFA-independent lipid-lowering effects, FFA rebound, and insulin resistance observed in clinics during NA treatment.
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Affiliation(s)
- Insug Kang
- Department of Biochemistry and Molecular Biology, Kyung Hee University School of Medicine, Seoul 1130-701, Korea
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11
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Oh YT, Oh KS, Choi YM, Jokiaho A, Donovan C, Choi S, Kang I, Youn JH. Continuous 24-h nicotinic acid infusion in rats causes FFA rebound and insulin resistance by altering gene expression and basal lipolysis in adipose tissue. Am J Physiol Endocrinol Metab 2011; 300:E1012-21. [PMID: 21386057 PMCID: PMC3118587 DOI: 10.1152/ajpendo.00650.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nicotinic acid (NA) has been used as a lipid drug for five decades. The lipid-lowering effects of NA are attributed to its ability to suppress lipolysis in adipocytes and lower plasma FFA levels. However, plasma FFA levels often rebound during NA treatment, offsetting some of the lipid-lowering effects of NA and/or causing insulin resistance, but the underlying mechanisms are unclear. The present study was designed to determine whether a prolonged, continuous NA infusion in rats produces a FFA rebound and/or insulin resistance. NA infusion rapidly lowered plasma FFA levels (>60%, P < 0.01), and this effect was maintained for ≥5 h. However, when this infusion was extended to 24 h, plasma FFA levels rebounded to the levels of saline-infused control rats. This was not due to a downregulation of NA action, because when the NA infusion was stopped, plasma FFA levels rapidly increased more than twofold (P < 0.01), indicating that basal lipolysis was increased. Microarray analysis revealed many changes in gene expression in adipose tissue, which would contribute to the increase in basal lipolysis. In particular, phosphodiesterase-3B gene expression decreased significantly, which would increase cAMP levels and thus lipolysis. Hyperinsulinemic glucose clamps showed that insulin's action on glucose metabolism was improved during 24-h NA infusion but became impaired with increased plasma FFA levels after cessation of NA infusion. In conclusion, a 24-h continuous NA infusion in rats resulted in an FFA rebound, which appeared to be due to altered gene expression and increased basal lipolysis in adipose tissue. In addition, our data support a previous suggestion that insulin resistance develops as a result of FFA rebound during NA treatment. Thus, the present study provides an animal model and potential molecular mechanisms of FFA rebound and insulin resistance, observed in clinical studies with chronic NA treatment.
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Affiliation(s)
- Young Taek Oh
- Department of Physiology and Biophysics, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA
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12
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Choi S, Yoon H, Oh KS, Oh YT, Kim YI, Kang I, Youn JH. Widespread effects of nicotinic acid on gene expression in insulin-sensitive tissues: implications for unwanted effects of nicotinic acid treatment. Metabolism 2011; 60:134-44. [PMID: 20303128 PMCID: PMC2912158 DOI: 10.1016/j.metabol.2010.02.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Revised: 02/09/2010] [Accepted: 02/11/2010] [Indexed: 11/26/2022]
Abstract
Nicotinic acid (NA; or niacin) has been used as a hypolipidemic agent for more than 4 decades. However, the mechanisms underlying the effects of NA treatment (wanted and unwanted) are still poorly understood. In the present study, we discovered that NA infusion in rats resulted in dephosphorylation (ie, activation) of the forkhead transcription factor FOXO1 in insulin-sensitive tissues such as skeletal and cardiac muscles, liver, and adipose tissue. These NA effects were opposite to the effects of insulin to increase FOXO1 phosphorylation. To test whether NA alters gene expression in these tissues, rats were infused for 7 hours with NA (30 μmol/h) and/or insulin (5 mU/[kg min]); and gene expression was evaluated using a microarray analysis. Nicotinic acid had widespread effects on gene expression in all of the tissues studied, and the number of genes affected by NA greatly exceeded that of genes affected by insulin. A systematic (or strategic) analysis of the microarray data revealed that there were numerous genes whose expression was regulated inversely by insulin and NA in correlation with FOXO1 phosphorylation, representing potential FOXO1 target genes. We also identified a group of genes whose expression was altered by NA exclusively in adipose tissue, presumably because of stimulation of the NA receptor in this tissue. Finally, there were genes whose expression was altered by both NA and insulin, likely via lowering plasma free fatty acid levels, including lipoprotein lipase and adenosine triphosphate-binding cassette A1, which play a major role in the regulation of circulating lipids. Thus, our data suggest that NA alters gene expression in insulin-sensitive tissues by various mechanisms. Some of the NA-induced changes in gene expression are discussed as potential mechanisms underlying wanted and unwanted effects of NA treatment.
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Affiliation(s)
- Sangdun Choi
- Department of Molecular Science and Technology, Ajou University, Suwon, Korea
| | - Hana Yoon
- Department of Biochemistry and Molecular Biology, Kyung Hee University, School of Medicine, Seoul, Korea
- Department of Physiology and Biophysics, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA
| | - Ki-Sook Oh
- Department of Physiology and Biophysics, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA
| | - Young Taek Oh
- Department of Biochemistry and Molecular Biology, Kyung Hee University, School of Medicine, Seoul, Korea
- Department of Physiology and Biophysics, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA
| | - Young I. Kim
- Department of Physiology and Biophysics, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA
| | - Insug Kang
- Department of Biochemistry and Molecular Biology, Kyung Hee University, School of Medicine, Seoul, Korea
| | - Jang H. Youn
- Department of Physiology and Biophysics, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA
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13
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Moro C, Bajpeyi S, Smith SR. Determinants of intramyocellular triglyceride turnover: implications for insulin sensitivity. Am J Physiol Endocrinol Metab 2008; 294:E203-13. [PMID: 18003718 DOI: 10.1152/ajpendo.00624.2007] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Increased intramyocellular triglyceride (IMTG) content is found in both insulin-sensitive endurance-trained subjects and insulin-resistant obese/type 2 diabetic subjects. A high turnover rate of the IMTG pool in athletes is proposed to reduce accumulation of lipotoxic intermediates interfering with insulin signaling. IMTG turnover is a composite measure of the dynamic balance between lipolysis and lipid synthesis; both are influenced by mitochondrial fat oxidation and plasma free fatty acid availability. Therefore, more attention should be given to the factors controlling the rate of turnover of IMTG. In this review, particular attention has been given to muscle oxidative capacity, plasma free fatty acid availability, and IMTG hydrolysis (lipolysis) and synthesis. A higher oxidative, lipolytic, and lipid storage capacity in the muscle of endurance-trained subjects reflects a higher fractional turnover of the IMTG pool. Thus the co-localization of intermyofibrillar lipid droplets and mitochondria allows for a fine coupling of lipolysis of the IMTG pool to mitochondrial beta-oxidation. Conversely, reduced oxidative capacity and a mismatch between IMTG lipolysis and beta-oxidation might be detrimental to insulin sensitivity by generating several lipotoxic intermediates in sedentary populations including obese/type 2 diabetic subjects. Further studies are clearly required to better understand the relationship between the rate of turnover of IMTG and the accumulation of lipotoxic intermediates in the pathophysiology of insulin resistance.
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Affiliation(s)
- Cédric Moro
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA
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14
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Holloway GP, Bezaire V, Heigenhauser GJF, Tandon NN, Glatz JFC, Luiken JJFP, Bonen A, Spriet LL. Mitochondrial long chain fatty acid oxidation, fatty acid translocase/CD36 content and carnitine palmitoyltransferase I activity in human skeletal muscle during aerobic exercise. J Physiol 2005; 571:201-10. [PMID: 16357012 PMCID: PMC1805655 DOI: 10.1113/jphysiol.2005.102178] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial fatty acid transport is a rate-limiting step in long chain fatty acid (LCFA) oxidation. In rat skeletal muscle, the transport of LCFA at the level of mitochondria is regulated by carnitine palmitoyltransferase I (CPTI) activity and the content of malonyl-CoA (M-CoA); however, this relationship is not consistently observed in humans. Recently, fatty acid translocase (FAT)/CD36 was identified on mitochondria isolated from rat and human skeletal muscle and found to be involved in LCFA oxidation. The present study investigated the effects of exercise (120 min of cycling at approximately 60% V(O2peak)) on CPTI palmitoyl-CoA and M-CoA kinetics, and on the presence and functional significance of FAT/CD36 on skeletal muscle mitochondria. Whole body fat oxidation rates progressively increased during exercise (P < 0.05), and concomitantly M-CoA inhibition of CPTI was progressively attenuated. Compared to rest, 120 min of cycling reduced (P < 0.05) the inhibition of 0.7, 2, 5 and 10 microM M-CoA by 16%, 21%, 30% and 34%, respectively. Whole body fat oxidation and palmitate oxidation rates in isolated mitochondria progressively increased (P < 0.05) during exercise, and were positively correlated (r = 0.78). Mitochondrial FAT/CD36 protein increased by 63% (P < 0.05) during exercise and was significantly (P < 0.05) correlated with mitochondrial palmitate oxidation rates at all time points (r= 0.41). However, the strongest (P < 0.05) correlation was observed following 120 min of cycling (r = 0.63). Importantly, the addition of sulfo-N-succimidyloleate, a specific inhibitor of FAT/CD36, reduced mitochondrial palmitate oxidation to approximately 20%, indicating FAT/CD36 is functionally significant with respect to LCFA oxidation. We hypothesize that exercise-induced increases in fatty acid oxidation occur as a result of an increased ability to transport LCFA into mitochondria. We further suggest that decreased CPTI M-CoA sensitivity and increased mitochondrial FAT/CD36 protein are both important for increasing whole body fatty acid oxidation during prolonged exercise.
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Affiliation(s)
- Graham P Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada.
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15
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Donsmark M, Langfort J, Holm C, Ploug T, Galbo H. Hormone-Sensitive Lipase as Mediator of Lipolysis in Contracting Skeletal Muscle. Exerc Sport Sci Rev 2005; 33:127-33. [PMID: 16006820 DOI: 10.1097/00003677-200507000-00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The authors propose that the enzyme hormone-sensitive lipase (HSL), which is the rate-limiting enzyme for hydrolysis of triacylglycerol in adipocytes, also regulates the intramyocellular triacylglycerol mobilization and is controlled by mechanisms similar to those regulating glycogen phosphorylase. From an exercise perspective, it is fascinating that the primary enzymatic setting allows simultaneous mobilization of all major extramuscular and intramuscular energy stores.
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Affiliation(s)
- Morten Donsmark
- Copenhagen Muscle Research Centre at Department of Medical Physiology, The Panum Institute, University of Copenhagen, Copenhagen, Denmark.
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