title: Low Cytochrome Oxidase 1 Links Mitochondrial Dysfunction to Atherosclerosis in Mice and Pigs.
abstract: BACKGROUND
  Cytochrome oxidase IV complex regulates energy production in mitochondria. Therefore, we determined the relation of COX genes with atherosclerosis in mice and pigs.
  
  
  RESULTS
  First, we compared atherosclerosis in the aortic arch of age-matched (24 weeks) C57BL/6J control (n = 10), LDL-receptor deficient (n = 8), leptin-deficient ob/ob (n = 10), and double knock-out (lacking LDL-receptor and leptin) mice (n = 12). Low aortic mitochondria-encoded cytochrome oxidase 1 in obese diabetic double knock-out mice was associated with a larger plaque area and higher propensity of M1 macrophages and oxidized LDL. Caloric restriction increased mitochondria-encoded cytochrome oxidase 1 and reduced plaque area and oxidized LDL. This was associated with a reduction of titer of anti-oxidized LDL antibodies, a proxy of systemic oxidative stress. Low of mitochondria-encoded cytochrome oxidase 1 was related to low expression of peroxisome proliferative activated receptors α, δ, and γ and of peroxisome proliferative activated receptor, gamma, co-activator 1 alpha reflecting mitochondrial dysfunction. Caloric restriction increased them. To investigate if there was a diabetic/obesity requirement for mitochondria-encoded cytochrome oxidase 1 to be down-regulated, we then studied atherosclerosis in LAD of hypercholesterolemic pigs (n = 37). Pigs at the end of the study were divided in three groups based on increasing LAD plaque complexity according to Stary (Stary I: n = 12; Stary II: n = 13; Stary III: n = 12). Low mitochondria-encoded cytochrome oxidase 1 in isolated plaque macrophages was associated with more complex coronary plaques and oxidized LDL. Nucleus-encoded cytochrome oxidase 4I1 and cytochrome oxidase 10 did not correlate with plaque complexity and oxidative stress. In mice and pigs, MT-COI was inversely related to insulin resistance.
  
  
  CONCLUSIONS
  Low MT-COI is related to mitochondrial dysfunction, oxidative stress and atherosclerosis and plaque complexity.
authors.affiliation: Department of Cardiovascular Sciences, Atherosclerosis and Metabolism Unit, KU Leuven, Belgium.
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0001-9201-0772
authors.initials: P
authors.lastname: Holvoet
authors.affiliation: Department of Clinical Cardiology, Leuven, Belgium.
authors.forename: Maarten
authors.initials: M
authors.lastname: Vanhaverbeke
authors.affiliation: Department of Cardiovascular Sciences, Atherosclerosis and Metabolism Unit, KU Leuven, Belgium.
authors.forename: Benjamine
authors.initials: B
authors.lastname: Geeraert
authors.affiliation: Department of Cardiovascular Sciences, Atherosclerosis and Metabolism Unit, KU Leuven, Belgium.
authors.forename: Dieuwke
authors.initials: D
authors.lastname: De Keyzer
authors.affiliation: Department of Cardiovascular Sciences, Atherosclerosis and Metabolism Unit, KU Leuven, Belgium.
authors.forename: Maarten
authors.initials: M
authors.lastname: Hulsmans
authors.affiliation: Department of Clinical Cardiology, Leuven, Belgium.
authors.forename: Stefan
authors.initials: S
authors.lastname: Janssens
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism / Q000473:pathology; D050197:Atherosclerosis / Q000201:enzymology / Q000209:etiology* / Q000235:genetics; D031204:Caloric Restriction; D003331:Coronary Vessels / Q000378:metabolism / Q000473:pathology; D030401:Cytochrome-c Oxidase Deficiency / Q000150:complications* / Q000473:pathology / Q000503:physiopathology*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000502:physiology*; D004734:Energy Metabolism; D006937:Hypercholesterolemia / Q000201:enzymology / Q000473:pathology; D007333:Insulin Resistance; D020738:Leptin / Q000172:deficiency / Q000235:genetics; D008077:Lipoproteins, LDL / Q000378:metabolism; D008264:Macrophages / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008820:Mice, Obese; D008928:Mitochondria / Q000378:metabolism*; D056918:Nuclear Receptor Coactivators / Q000096:biosynthesis / Q000235:genetics; D018384:Oxidative Stress; D047492:Peroxisome Proliferator-Activated Receptors / Q000096:biosynthesis / Q000235:genetics; D058226:Plaque, Atherosclerotic / Q000473:pathology; D011973:Receptors, LDL / Q000172:deficiency / Q000235:genetics; D054411:Receptors, Leptin / Q000172:deficiency / Q000235:genetics; D013552:Swine; D013556:Swine, Miniature / Q000378:metabolism*
chemical_list: D020738:Leptin; D008077:Lipoproteins, LDL; C405683:Ncoa6 protein, mouse; D056918:Nuclear Receptor Coactivators; D047492:Peroxisome Proliferator-Activated Receptors; D011973:Receptors, LDL; D054411:Receptors, Leptin; C515447:leptin receptor, mouse; C099252:oxidized low density lipoprotein; C000604261:Cox4i1 protein, mouse; D003576:Electron Transport Complex IV