title: Omega-3 supplementation alters mitochondrial membrane composition and respiration kinetics in human skeletal muscle.
abstract: Studies have shown increased incorporation of omega-3 fatty acids into whole skeletal muscle following supplementation, although little has been done to investigate the potential impact on the fatty acid composition of mitochondrial membranes and the functional consequences on mitochondrial bioenergetics. Therefore, we supplemented young healthy male subjects (n = 18) with fish oils [2 g eicosapentaenoic acid (EPA) and 1 g docosahexanoic acid (DHA) per day] for 12 weeks and skeletal muscle biopsies were taken prior to (Pre) and following (Post) supplementation for the analysis of mitochondrial membrane phospholipid composition and various assessments of mitochondrial bioenergetics. Total EPA and DHA content in mitochondrial membranes increased (P < 0.05) ∼450 and ∼320%, respectively, and displaced some omega-6 species in several phospholipid populations. Mitochondrial respiration, determined in permeabilized muscle fibres, demonstrated no change in maximal substrate-supported respiration, or in the sensitivity (apparent Km) and maximal capacity for pyruvate-supported respiration. In contrast, mitochondrial responses during ADP titrations demonstrated an enhanced ADP sensitivity (decreased apparent Km) that was independent of the creatine kinase shuttle. As the content of ANT1, ANT2, and subunits of the electron transport chain were unaltered by supplementation, these data suggest that prolonged omega-3 intake improves ADP kinetics in human skeletal muscle mitochondria through alterations in membrane structure and/or post-translational modification of ATP synthase and ANT isoforms. Omega-3 supplementation also increased the capacity for mitochondrial reactive oxygen species emission without altering the content of oxidative products, suggesting the absence of oxidative damage. The current data strongly emphasize a role for omega-3s in reorganizing the composition of mitochondrial membranes while promoting improvements in ADP sensitivity.
authors.affiliation: Human Health and Nutritional Sciences, University of Guelph, 491 Gordon St., Guelph, ON N1G 2W1, Canada. ghollowa@uoguelph.ca.
authors.forename: E A F
authors.initials: EA
authors.lastname: Herbst
authors.forename: S
authors.initials: S
authors.lastname: Paglialunga
authors.forename: C
authors.initials: C
authors.lastname: Gerling
authors.forename: J
authors.initials: J
authors.lastname: Whitfield
authors.forename: K
authors.initials: K
authors.lastname: Mukai
authors.forename: A
authors.initials: A
authors.lastname: Chabowski
authors.forename: G J F
authors.initials: GJ
authors.lastname: Heigenhauser
authors.forename: L L
authors.initials: LL
authors.lastname: Spriet
authors.forename: G P
authors.initials: GP
authors.lastname: Holloway
mesh_terms: D033741:Adenine Nucleotide Translocator 1 / Q000378:metabolism; D033742:Adenine Nucleotide Translocator 2 / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism; D019069:Cell Respiration / Q000502:physiology; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000493:pharmacokinetics; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics; D004734:Energy Metabolism; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism; D018384:Oxidative Stress; D010743:Phospholipids / Q000378:metabolism; D052097:Quadriceps Muscle / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D055815:Young Adult
chemical_list: D033741:Adenine Nucleotide Translocator 1; D033742:Adenine Nucleotide Translocator 2; D015525:Fatty Acids, Omega-3; D010743:Phospholipids; D017382:Reactive Oxygen Species; C580832:SLC25A4 protein, human; D004281:Docosahexaenoic Acids; D000244:Adenosine Diphosphate; D015118:Eicosapentaenoic Acid; D006861:Hydrogen Peroxide