title: Mitochondrial oxidative stress and nitrate tolerance--comparison of nitroglycerin and pentaerithrityl tetranitrate in Mn-SOD+/- mice.
abstract: BACKGROUND
  Chronic therapy with nitroglycerin (GTN) results in a rapid development of nitrate tolerance which is associated with an increased production of reactive oxygen species (ROS). According to recent studies, mitochondrial ROS formation and oxidative inactivation of the organic nitrate bioactivating enzyme mitochondrial aldehyde dehydrogenase (ALDH-2) play an important role for the development of nitrate and cross-tolerance.
  
  
  METHODS
  Tolerance was induced by infusion of wild type (WT) and heterozygous manganese superoxide dismutase mice (Mn-SOD+/-) with ethanolic solution of GTN (12.5 mug/min/kg for 4 d). For comparison, the tolerance-free pentaerithrityl tetranitrate (PETN, 17.5 mug/min/kg for 4 d) was infused in DMSO. Vascular reactivity was measured by isometric tension studies of isolated aortic rings. ROS formation and aldehyde dehydrogenase (ALDH-2) activity was measured in isolated heart mitochondria.
  
  
  RESULTS
  Chronic GTN infusion lead to impaired vascular responses to GTN and acetylcholine (ACh), increased the ROS formation in mitochondria and decreased ALDH-2 activity in Mn-SOD+/- mice. In contrast, PETN infusion did not increase mitochondrial ROS formation, did not decrease ALDH-2 activity and accordingly did not lead to tolerance and cross-tolerance in Mn-SOD+/- mice. PETN but not GTN increased heme oxygenase-1 mRNA in EA.hy 926 cells and bilirubin efficiently scavenged GTN-derived ROS.
  
  
  CONCLUSIONS
  Chronic GTN infusion stimulates mitochondrial ROS production which is an important mechanism leading to tolerance and cross-tolerance. The tetranitrate PETN is devoid of mitochondrial oxidative stress induction and according to the present animal study as well as numerous previous clinical studies can be used without limitations due to tolerance and cross-tolerance.
authors.affiliation: The 2nd Medical Clinic, Johannes Gutenberg-University, Mainz, Germany. mollnau@uni-mainz.de <mollnau@uni-mainz.de>
authors.forename: Hanke
authors.initials: H
authors.lastname: Mollnau
authors.forename: Philip
authors.initials: P
authors.lastname: Wenzel
authors.forename: Matthias
authors.initials: M
authors.lastname: Oelze
authors.forename: Nicolai
authors.initials: N
authors.lastname: Treiber
authors.forename: Andrea
authors.initials: A
authors.lastname: Pautz
authors.forename: Eberhard
authors.initials: E
authors.lastname: Schulz
authors.forename: Swenja
authors.initials: S
authors.lastname: Schuhmacher
authors.forename: Kurt
authors.initials: K
authors.lastname: Reifenberg
authors.forename: Dirk
authors.initials: D
authors.lastname: Stalleicken
authors.forename: Karin
authors.initials: K
authors.lastname: Scharffetter-Kochanek
authors.forename: Hartmut
authors.initials: H
authors.lastname: Kleinert
authors.forename: Thomas
authors.initials: T
authors.lastname: Münzel
authors.forename: Andreas
authors.initials: A
authors.lastname: Daiber
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001663:Bilirubin / Q000378:metabolism; D002460:Cell Line; D004334:Drug Administration Schedule; D004361:Drug Tolerance; D016166:Free Radical Scavengers / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008929:Mitochondria, Heart / Q000378:metabolism*; D005996:Nitroglycerin / Q000008:administration & dosage / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D010417:Pentaerythritol Tetranitrate / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors; D013482:Superoxide Dismutase / Q000172:deficiency* / Q000235:genetics; D014664:Vasodilation; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D016166:Free Radical Scavengers; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014665:Vasodilator Agents; D010417:Pentaerythritol Tetranitrate; D051547:Heme Oxygenase-1; D013482:Superoxide Dismutase; C515029:ALDH2 protein, mouse; D000444:Aldehyde Dehydrogenase; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D005996:Nitroglycerin; D000109:Acetylcholine; D001663:Bilirubin