Quantitative Redox Biology of Exercise

Abstract

Biology is rich in claims that reactive oxygen and nitrogen species are involved in every biological process and disease. However, many quantitative aspects of redox biology remain elusive. The important quantitative parameters you need to address the feasibility of redox reactions in vivo are: rate of formation and consumption of a reactive oxygen and nitrogen species, half-life, diffusibility and membrane permeability. In the first part, we explain the basic chemical kinetics concepts and algebraic equations required to perform “street fighting” quantitative analysis. In the second part, we provide key numbers to help thinking about sizes, concentrations, rates and other important quantities that describe the major oxidants (superoxide, hydrogen peroxide, nitric oxide) and antioxidants (vitamin C, vitamin E, glutathione). In the third part, we present the quantitative effect of exercise on superoxide, hydrogen peroxide and nitric oxide concentration in mitochondria and whole muscle and calculate how much hydrogen peroxide concentration needs to increase to transduce signalling. By taking into consideration the quantitative aspects of redox biology we can: i) refine the broad understanding of this research area, ii) design better future studies and facilitate comparisons among studies, and iii) define more efficiently the “borders” between cellular signaling and stress.

Key words

free radicals - oxidative stress - oxidation - oxidative damage - skeletal muscle - training adaptations

Publication History

Received: 14 January 2020

Accepted: 30 March 2020

Article published online:
26 May 2020

• References

• 1 Nikolaidis MG, Margaritelis NV. Same redox evidence but different physiological “stories”: The Rashomon effect in biology. Bioessays 2018; 40: e1800041. doi:10.1002/bies.201800041
• 2 Margaritelis NV, Cobley JN, Paschalis V. et al. Principles for integrating reactive species into in vivo biological processes: Examples from exercise physiology. Cell Signal 2016; 28: 256-271.
• 3 Powers SK, Jackson MJ. Exercise-induced oxidative stress: Cellular mechanisms and impact on muscle force production. Physiol Rev 2008; 88: 1243-1276. doi:10.1152/physrev.00031.2007
• 4 Dolopikou CF, Kourtzidis IA, Margaritelis NV. et al. Acute nicotinamide riboside supplementation improves redox homeostasis and exercise performance in old individuals: A double-blind cross-over study. Eur J Nutr 2019;
• 5 Georgakouli K, Fatouros IG, Fragkos A. et al. Exercise and redox status responses following alpha-lipoic acid supplementation in G6PD deficient individuals. Antioxidants (Basel) 2018; 7: 162.
• 6 Kourtzidis IA, Dolopikou CF, Tsiftsis AN. et al. Nicotinamide riboside supplementation dysregulates redox and energy metabolism in rats: Implications for exercise performance. Exp Physiol 2018; 103: 1357-1366.
• 7 Margaritelis NV, Paschalis V, Theodorou AA. et al. Antioxidants in personalized nutrition and exercise. Adv Nutr 2018; 9: 813-823
• 8 Margaritelis NV, Paschalis V, Theodorou AA. et al. Rapid decreases of key antioxidant molecules in critically ill patients: A personalized approach. Clin Nutr 2019;
• 9 Paschalis V, Theodorou AA, Kyparos A. et al. Low vitamin C values are linked with decreased physical performance and increased oxidative stress: Reversal by vitamin C supplementation. Eur J Nutr 2016; 55: 45-53.
• 10 Paschalis V, Theodorou AA, Margaritelis NV. et al. N-acetylcysteine supplementation increases exercise performance and reduces oxidative stress only in individuals with low levels of glutathione. Free Radic Biol Med 2018; 115: 288-297.
• 11 Nikolaidis MG, Kyparos A, Spanou C. et al. Redox biology of exercise: An integrative and comparative consideration of some overlooked issues. J Exp Biol 2012; 215: 1615-1625.
• 12 Tryfidou DV, McClean C, Nikolaidis MG. et al. DNA damage following acute aerobic exercise: A systematic review and meta-analysis. Sports Med 2020; 50: 103-127
• 13 Held JM. Redox systems biology: Harnessing the sentinels of the cysteine redoxome. Antioxid Redox Signal 2020; 32: 659-676
• 14 Cheng AJ, Yamada T, Rassier DE. et al. Reactive oxygen/nitrogen species and contractile function in skeletal muscle during fatigue and recovery. J Physiol 2016; 594: 5149-5160.
• 15 Cobley JN, Close GL, Bailey DM. et al. Exercise redox biochemistry: Conceptual, methodological and technical recommendations. Redox Biol 2017; 12: 540-548.
• 16 Gomez-Cabrera MC, Salvador-Pascual A, Cabo H. et al. Redox modulation of mitochondriogenesis in exercise. Does antioxidant supplementation blunt the benefits of exercise training?. Free Radic Biol Med 2015; 86: 37-46.
• 17 Neufer PD. The bioenergetics of exercise. Cold Spring Harb Perspect Med. 2018: 8-a029678
• 18 Radak Z, Zhao Z, Koltai E. et al. Oxygen consumption and usage during physical exercise: The balance between oxidative stress and ROS-dependent adaptive signaling. Antioxid Redox Signal 2013; 18: 1208-1246
• 19 Reid MB. Reactive oxygen species as agents of fatigue. Med Sci Sports Exerc 2016; 48: 2239-2246. doi:10.1249/MSS.0000000000001006
• 20 Flohe L. The fairytale of the GSSG/GSH redox potential. Biochim Biophys Acta 2013; 1830: 3139-3142 doi:10.1016/j.bbagen.2012.10.020
• 21 Schafer FQ, Buettner GR. Redox environment of the cell as viewed through the redox state of the glutathione disulfide/glutathione couple. Free Radic Biol Med 2001; 30: 1191-1212. doi:10.1016/s0891-5849(01)00480-4
• 22 Lee JK, Walker KL, Han HS. et al. Spontaneous generation of hydrogen peroxide from aqueous microdroplets. Proc Natl Acad Sci USA 2019; 116: 19294-19298
• 23 Halliwell B, Gutteridge JMC. Free Radicals in Biology and Medicine. 5^th edition Oxford: Oxford University Press; 2015
• 24 Harriss DJ, MacSween A, Atkinson G. Ethical standards in sport and exercise science research: 2020 update. Int J Sports Med 2019; 40: 813-817. doi:10.1055/a-1015-3123
• 25 Koppenol WH, Bounds PL. Signaling by sulfur-containing molecules. Quantitative aspects. Arch Biochem Biophys 2017; 617: 3-8 doi:10.1016/j.abb.2016.09.012
• 26 Winterbourn CC. The biological chemistry of hydrogen peroxide. Methods Enzymol 2013; 528: 3-25. doi:10.1016/B978-0-12-405881-1.00001-X
• 27 Antunes F, Brito PM. Quantitative biology of hydrogen peroxide signaling. Redox Biol 2017; 13: 1-7 doi:10.1016/j.redox.2017.04.039
• 28 Parvez S, Long MJC, Poganik JR. et al. Redox signaling by reactive electrophiles and oxidants. Chem Rev 2018; 118: 8798-8888
• 29 Lancaster JR. A tutorial on the diffusibility and reactivity of free nitric oxide. Nitric Oxide 1997; 1: 18-30 doi:10.1006/niox.1996.0112
• 30 Phillips R, Kondev J, Theriot J. et al. Physical Biology of the Cell. 2^nd edition New York: Garland Science; 2012
• 31 Milo R, Phillips R. Cell Biology by the Numbers. New York: Garland Science; 2016
• 32 Winterbourn CC. Reconciling the chemistry and biology of reactive oxygen species. Nat Chem Biol 2008; 4: 278-286. doi:10.1038/nchembio.85
• 33 Hegarty PV, Hooper AC. Sarcomere length and fibre diameter distributions in four different mouse skeletal muscles. J Anat 1971; 110: 249-257
• 34 Kinsey ST, Locke BR, Dillaman RM. Molecules in motion: influences of diffusion on metabolic structure and function in skeletal muscle. J Exp Biol 2011; 214: 263-274. doi:10.1242/jeb.047985
• 35 Moller MN, Rios N, Trujillo M. et al. Detection and quantification of nitric oxide-derived oxidants in biological systems. J Biol Chem 2019; 294: 14776-14802
• 36 Moller MN, Cuevasanta E, Orrico F. et al. Diffusion and transport of reactive species across cell membranes. Adv Exp Med Biol 2019; 1127: 3-19.
• 37 Huang BK, Sikes HD. Quantifying intracellular hydrogen peroxide perturbations in terms of concentration. Redox Biol 2014; 2: 955-962. doi:10.1016/j.redox.2014.08.001
• 38 Nikolaidis MG, Kyparos A, Vrabas IS. F(2)-isoprostane formation, measurement and interpretation: The role of exercise. Prog Lipid Res 2011; 50: 89-103. doi:10.1016/j.plipres.2010.10.002
• 39 Gulaboski R, Mirčeski V, Kappl R. et al. Quantification of hydrogen peroxide by electrochemical methods and electron spin resonance spectroscopy. J Electrochem Soc 2019; 166: G82-G101
• 40 Radi R. Oxygen radicals, nitric oxide, and peroxynitrite: Redox pathways in molecular medicine. Proc Natl Acad Sci USA 2018; 115: 5839-5848 doi:10.1073/pnas.1804932115
• 41 Cobley JN, Sakellariou GK, Husi H. et al. Proteomic strategies to unravel age-related redox signalling defects in skeletal muscle. Free Radic Biol Med 2019; 132: 24-32.
• 42 Goncalves RLS, Watson MA, Wong HS. et al. The use of site-specific suppressors to measure the relative contributions of different mitochondrial sites to skeletal muscle superoxide and hydrogen peroxide production. Redox Biol 2020; 28: 101341.
• 43 Henriquez-Olguin C, Boronat S, Cabello-Verrugio C. et al. The emerging roles of nicotinamide adenine dinucleotide phosphate oxidase 2 in skeletal muscle redox signaling and metabolism. Antioxid Redox Signal 2019; 31: 1371-1410.
• 44 Sakellariou GK, Jackson MJ, Vasilaki A. Redefining the major contributors to superoxide production in contracting skeletal muscle. The role of NAD(P)H oxidases. Free Radic Res 2014; 48: 12-29. doi:10.3109/10715762.2013.830718
• 45 Forman HJ, Bernardo A, Davies KJ. What is the concentration of hydrogen peroxide in blood and plasma?. Arch Biochem Biophys 2016; 603: 48-53. doi:10.1016/j.abb.2016.05.005
• 46 Sikes HD. Quantification of intracellular H2O2: Methods and significance. Oxidative Stress 2019; 113-124
• 47 Weydert CJ, Cullen JJ. Measurement of superoxide dismutase, catalase and glutathione peroxidase in cultured cells and tissue. Nat Protoc 2010; 5: 51-66. doi:10.1038/nprot.2009.197
• 48 Forman HJ, Fridovich I. Superoxide dismutase: A comparison of rate constants. Arch Biochem Biophys 1973; 158: 396-400. doi:10.1016/0003-9861(73)90636-x
• 49 Foyer CH, Noctor G. Stress-triggered redox signalling: What’s in pROSpect?. Plant Cell Environ 2016; 39: 951-964. doi:10.1111/pce.12621
• 50 Li X, Imlay JA. Improved measurements of scant hydrogen peroxide enable experiments that define its threshold of toxicity for Escherichia coli. Free Radic Biol Med 2018; 120: 217-227. doi:10.1016/j.freeradbiomed.2018.03.025
• 51 Moller MN, Denicola A. Diffusion of nitric oxide and oxygen in lipoproteins and membranes studied by pyrene fluorescence quenching. Free Radic Biol Med 2018; 128: 137-143 doi:10.1016/j.freeradbiomed.2018.04.553
• 52 Loureiro AC, do Rego-Monteiro IC, Louzada RA. et al. Differential expression of NADPH oxidases depends on skeletal muscle fiber type in rats. Oxid Med Cell Longev 2016; 2016: 6738701
• 53 Buettner GR, Wagner BA, Rodgers VG. Quantitative redox biology: An approach to understand the role of reactive species in defining the cellular redox environment. Cell Biochem Biophys 2013; 67: 477-483. doi:10.1007/s12013-011-9320-3
• 54 Nikolaidis MG, Jamurtas AZ. Blood as a reactive species generator and redox status regulator during exercise. Arch Biochem Biophys 2009; 490: 77-84. doi:10.1016/j.abb.2009.08.015
• 55 Turell L, Radi R, Alvarez B. The thiol pool in human plasma: The central contribution of albumin to redox processes. Free Radic Biol Med 2013; 65: 244-253. doi:10.1016/j.freeradbiomed.2013.05.050
• 56 Clifford T, Jeffries O, Stevenson EJ. et al. The effects of vitamin C and E on exercise-induced physiological adaptations: A systematic review and meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr 2019; 1-11.
• 57 Nyberg M, Mortensen SP, Cabo H. et al. Roles of sedentary aging and lifelong physical activity in exchange of glutathione across exercising human skeletal muscle. Free Radic Biol Med 2014; 73: 166-173.
• 58 Niki E. Role of vitamin E as a lipid-soluble peroxyl radical scavenger: In vitro and in vivo evidence. Free Radic Biol Med 2014; 66: 3-12. doi:10.1016/j.freeradbiomed.2013.03.022
• 59 Traber MG, Stevens JF. Vitamins C and E: Beneficial effects from a mechanistic perspective. Free Radic Biol Med 2011; 51: 1000-1013. doi:10.1016/j.freeradbiomed.2011.05.017
• 60 Traber MG, Atkinson J. Vitamin E, antioxidant and nothing more. Free Radic Biol Med 2007; 43: 4-15. doi:10.1016/j.freeradbiomed.2007.03.024
• 61 Niki E. Tocopherylquinone and tocopherylhydroquinone. Redox Rep 2007; 12: 204-210. doi:10.1179/135100007X200353
• 62 Brigelius-Flohé R, Maiorino M. Glutathione peroxidases. Biochim Biophys Acta 2013; 1830: 3289-3303 doi:10.1016/j.bbagen.2012.11.020
• 63 Winther JR, Jakob U. Redox control: A black hole for oxidized glutathione. Nat Chem Biol 2013; 9: 69-70. doi:10.1038/nchembio.1161
• 64 Nikolaidis MG, Margaritelis NV, Paschalis V. et al. Common questions and tentative answers on how to assess oxidative stress after antioxidant supplementation and exercise. In: Lamprecht M, Ed. Antioxidants in Sport Nutrition Boca Raton (FL): CRC Press; 2015
• 65 Aon MA, Cortassa S, O’Rourke B. Redox-optimized ROS balance: A unifying hypothesis. Biochim Biophys Acta 2010; 1797: 865-877 doi:10.1016/j.bbabio.2010.02.016
• 66 Go YM, Jones DP. Thiol/disulfide redox states in signaling and sensing. Crit Rev Biochem Mol Biol 2013; 48: 173-181. doi:10.3109/10409238.2013.764840
• 67 Margaritelis NV, Cobley JN, Paschalis V. et al. Going retro: Oxidative stress biomarkers in modern redox biology. Free Radic Biol Med 2016; 98: 2-12
• 68 Aydin J, Andersson DC, Hanninen SL. et al. Increased mitochondrial Ca2+ and decreased sarcoplasmic reticulum Ca2+ in mitochondrial myopathy. Hum Mol Genet 2009; 18: 278-288
• 69 Cheng AJ, Bruton JD, Lanner JT. et al. Antioxidant treatments do not improve force recovery after fatiguing stimulation of mouse skeletal muscle fibres. J Physiol 2015; 593: 457-472.
• 70 Diaz-Vegas A, Campos CA, Contreras-Ferrat A. et al. ROS production via P2Y1-PKC-NOX2 is triggered by extracellular ATP after electrical stimulation of skeletal muscle cells. PLoS One 2015; 10: e0129882.
• 71 Grundtman C, Bruton J, Yamada T. et al. Effects of HMGB1 on in vitro responses of isolated muscle fibers and functional aspects in skeletal muscles of idiopathic inflammatory myopathies. FASEB J 2010; 24: 570-578.
• 72 Henriquez-Olguin C, Altamirano F, Valladares D. et al. Altered ROS production, NF-kappaB activation and interleukin-6 gene expression induced by electrical stimulation in dystrophic mdx skeletal muscle cells. Biochim Biophys Acta 2015; 1852: 1410-1419.
• 73 Henriquez-Olguin C, Knudsen JR, Raun SH. et al. Cytosolic ROS production by NADPH oxidase 2 regulates muscle glucose uptake during exercise. Nat Commun 2019; 10: 4623.
• 74 Henriquez-Olguin C, Renani LB, Arab-Ceschia L. et al. Adaptations to high-intensity interval training in skeletal muscle require NADPH oxidase 2. Redox Biol 2019; 24: 101188.
• 75 Liu Y, Hernandez-Ochoa EO, Randall WR. et al. NOX2-dependent ROS is required for HDAC5 nuclear efflux and contributes to HDAC4 nuclear efflux during intense repetitive activity of fast skeletal muscle fibers. Am J Physiol Cell Physiol 2012; 303: C334-347.
• 76 Michaelson LP, Shi G, Ward CW. et al. Mitochondrial redox potential during contraction in single intact muscle fibers. Muscle Nerve 2010; 42: 522-529.
• 77 Miotto PM, Holloway GP. Exercise-induced reductions in mitochondrial ADP sensitivity contribute to the induction of gene expression and mitochondrial biogenesis through enhanced mitochondrial H2O2 emission. Mitochondrion 2019; 46: 116-122. doi:10.1016/j.mito.2018.03.003
• 78 Pal R, Basu Thakur P, Li S. et al. Real-time imaging of NADPH oxidase activity in living cells using a novel fluorescent protein reporter. PLoS One 2013; 8: e63989
• 79 Pattwell DM, McArdle A, Morgan JE. et al. Release of reactive oxygen and nitrogen species from contracting skeletal muscle cells. Free Radic Biol Med 2004; 37: 1064-1072.
• 80 Pearson T, Kabayo T, Ng R. et al. Skeletal muscle contractions induce acute changes in cytosolic superoxide, but slower responses in mitochondrial superoxide and cellular hydrogen peroxide. PLoS One 2014; 9: e96378.
• 81 Pearson T, McArdle A, Jackson MJ. Nitric oxide availability is increased in contracting skeletal muscle from aged mice, but does not differentially decrease muscle superoxide. Free Radic Biol Med 2015; 78: 82-88. doi:10.1016/j.freeradbiomed.2014.10.505
• 82 Place N, Ivarsson N, Venckunas T. et al. Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise. Proc Natl Acad Sci USA 2015; 112: 15492-15497.
• 83 Pye D, Palomero J, Kabayo T. et al. Real-time measurement of nitric oxide in single mature mouse skeletal muscle fibres during contractions. J Physiol 2007; 581: 309-318
• 84 Vasilaki A, Mansouri A, Van Remmen H. et al. Free radical generation by skeletal muscle of adult and old mice: Effect of contractile activity. Aging Cell 2006; 5: 109-117.
• 85 Wei L, Salahura G, Boncompagni S. et al. Mitochondrial superoxide flashes: Metabolic biomarkers of skeletal muscle activity and disease. FASEB J 2011; 25: 3068-3078
• 86 Anderson EJ, Yamazaki H, Neufer PD. Induction of endogenous uncoupling protein 3 suppresses mitochondrial oxidant emission during fatty acid-supported respiration. J Biol Chem 2007; 282: 31257-31266 doi:10.1074/jbc.M706129200
• 87 Balon TW, Nadler JL. Nitric oxide release is present from incubated skeletal muscle preparations. J Appl Physiol (1985) 1994; 77: 2519-2521. doi:10.1152/jappl.1994.77.6.2519
• 88 Espinosa A, Leiva A, Pena M. et al. Myotube depolarization generates reactive oxygen species through NAD(P)H oxidase; ROS-elicited Ca2+ stimulates ERK, CREB, early genes. J Cell Physiol 2006; 209: 379-388
• 89 Lambertucci RH, Silveira Ldos R, Hirabara SM. et al. Effects of moderate electrical stimulation on reactive species production by primary rat skeletal muscle cells: Cross talk between superoxide and nitric oxide production. J Cell Physiol 2012; 227: 2511-2518
• 90 Pinheiro CH, Silveira LR, Nachbar RT. et al. Regulation of glycolysis and expression of glucose metabolism-related genes by reactive oxygen species in contracting skeletal muscle cells. Free Radic Biol Med 2010; 48: 953-960.
• 91 Silveira LR, Pereira-Da-Silva L, Juel C. et al. Formation of hydrogen peroxide and nitric oxide in rat skeletal muscle cells during contractions. Free Radic Biol Med 2003; 35: 455-464.
• 92 Petrick HL, Pignanelli C, Barbeau PA. et al. Blood flow restricted resistance exercise and reductions in oxygen tension attenuate mitochondrial H2O2 emission rates in human skeletal muscle. J Physiol 2019; 597: 3985-3997.
• 93 Trewin AJ, Levinger I, Parker L. et al. Acute exercise alters skeletal muscle mitochondrial respiration and H2O2 emission in response to hyperinsulinemic-euglycemic clamp in middle-aged obese men. PLoS One 2017; 12: e0188421.
• 94 Hardy M, Zielonka J, Karoui H. et al. Detection and characterization of reactive oxygen and nitrogen species in biological systems by monitoring species-specific products. Antioxid Redox Signal 2018; 28: 1416-1432.
• 95 Kalyanaraman B, Darley-Usmar V, Davies KJ. et al. Measuring reactive oxygen and nitrogen species with fluorescent probes: Challenges and limitations. Free Radic Biol Med 2012; 52: 1-6
• 96 Zhang Y, Dai M, Yuan Z. Methods for the detection of reactive oxygen species. Anal Methods 2018; 10: 4625-4638
• 97 Lyublinskaya O, Antunes F. Measuring intracellular concentration of hydrogen peroxide with the use of genetically encoded H2O2 biosensor HyPer. Redox Biol 2019; 24: 101200. doi:10.1016/j.redox.2019.101200
• 98 Schroder K. NADPH oxidase-derived reactive oxygen species: Dosis facit venenum. Exp Physiol 2019; 104: 447-452 doi:10.1113/EP087125
• 99 Xu X, Arriaga EA. Chemical cytometry quantitates superoxide levels in the mitochondrial matrix of single myoblasts. Anal Chem 2010; 82: 6745-6750. doi:10.1021/ac101509d
• 100 Bartesaghi S, Radi R. Fundamentals on the biochemistry of peroxynitrite and protein tyrosine nitration. Redox Biol 2018; 14: 618-625. doi:10.1016/j.redox.2017.09.009
• 101 Chen K, Pittman RN, Popel AS. Nitric oxide in the vasculature: Where does it come from and where does it go? A quantitative perspective. Antioxid Redox Signal 2008; 10: 1185-1198 doi:10.1089/ars.2007.1959
• 102 Hall CN, Garthwaite J. What is the real physiological NO concentration in vivo?. Nitric Oxide 2009; 21: 92-103 doi:10.1016/j.niox.2009.07.002
• 103 Winterbourn CC, Metodiewa D. The reaction of superoxide with reduced glutathione. Arch Biochem Biophys 1994; 314: 284-290 doi:10.1006/abbi.1994.1444
• 104 Carr AC, Bozonet SM, Pullar JM. et al. Human skeletal muscle ascorbate is highly responsive to changes in vitamin C intake and plasma concentrations. Am J Clin Nutr 2013; 97: 800-807.
• 105 Hickey S, Roberts H. Misleading information on the properties of vitamin C. PLoS Med 2005; 2: e307. author reply e309. doi:10.1371/journal.pmed.0020307
• 106 Buettner GR, Jurkiewicz BA. Ascorbate radical: A valuable marker of oxidative stress. In: Favier AE, Cadet J, Kalyanaraman B, Fontecave M, Pierre J-L, eds. Analysis of Free Radicals in Biological Systems. Basel: Birkhäuser; 1995
• 107 Padayatty SJ, Levine M. Vitamins C and E and the prevention of preeclampsia. N Engl J Med 2006; 355: 1065-1066 author reply 1066. doi:10.1056/NEJMc061414
• 108 Dhariwal KR, Hartzell WO, Levine M. Ascorbic acid and dehydroascorbic acid measurements in human plasma and serum. Am J Clin Nutr 1991; 54: 712-716 doi:10.1093/ajcn/54.4.712
• 109 Bode AM, Cunningham L, Rose RC. Spontaneous decay of oxidized ascorbic acid (dehydro-L-ascorbic acid) evaluated by high-pressure liquid chromatography. Clin Chem 1990; 36: 1807-1809
• 110 Traber MG. Vitamin E inadequacy in humans: Causes and consequences. Adv Nutr 2014; 5: 503-514. doi:10.3945/an.114.006254
• 111 Meydani M, Fielding RA, Cannon JG. et al. Muscle uptake of vitamin E and its association with muscle fiber type. J Nutr Biochem 1997; 8: 74-78
• 112 Traber MG, Leonard SW, Bobe G. et al. alpha-Tocopherol disappearance rates from plasma depend on lipid concentrations: Studies using deuterium-labeled collard greens in younger and older adults. Am J Clin Nutr 2015; 101: 752-759
• 113 Veskoukis AS, Kyparos A, Paschalis V. et al. Spectrophotometric assays for measuring redox biomarkers in blood. Biomarkers 2016; 21: 208-217.
• 114 Jones DP, Carlson JL, Mody VC. et al. Redox state of glutathione in human plasma. Free Radic Biol Med 2000; 28: 625-635.
• 115 Giustarini D, Colombo G, Garavaglia ML. et al. Assessment of glutathione/glutathione disulphide ratio and S-glutathionylated proteins in human blood, solid tissues, and cultured cells. Free Radic Biol Med 2017; 112: 360-375
• 116 Agostini F, Dalla Libera L, Rittweger J. et al. Effects of inactivity on human muscle glutathione synthesis by a double-tracer and single-biopsy approach. J Physiol 2010; 588: 5089-5104
• 117 Margaritelis NV, Theodorou AA, Paschalis V. et al. Adaptations to endurance training depend on exercise-induced oxidative stress: Exploiting redox interindividual variability. Acta Physiol (Oxf) 2018; 222
• 118 Veskoukis AS, Tsatsakis A, Kouretas D. Approaching reactive species in the frame of their clinical significance: A toxicological appraisal. Food Chem Toxicol 2020; 138: 111206. doi: 10.1016/j.fct.2020.111206