title: Impact of eNOS-Dependent Oxidative Stress on Endothelial Function and Neointima Formation.
abstract: OBJECTIVE
  Vascular oxidative stress generated by endothelial NO synthase (eNOS) was observed in experimental and clinical cardiovascular disease, but its relative importance for vascular pathologies is unclear. We investigated the impact of eNOS-dependent vascular oxidative stress on endothelial function and on neointimal hyperplasia.
  
  
  RESULTS
  A dimer-destabilized mutant of bovine eNOS where cysteine 101 was replaced by alanine was cloned and introduced into an eNOS-deficient mouse strain (eNOS-KO) in an endothelial-specific manner. Destabilization of mutant eNOS in cells and eNOS-KO was confirmed by the reduced dimer/monomer ratio. Purified mutant eNOS and transfected cells generated less citrulline and NO, respectively, while superoxide generation was enhanced. In eNOS-KO, introduction of mutant eNOS caused a 2.3-3.7-fold increase in superoxide and peroxynitrite formation in the aorta and myocardium. This was completely blunted by an NOS inhibitor. Nevertheless, expression of mutant eNOS in eNOS-KO completely restored maximal aortic endothelium-dependent relaxation to acetylcholine. Neointimal hyperplasia induced by carotid binding was much larger in eNOS-KO than in mutant eNOS-KO and C57BL/6, while the latter strains showed comparable hyperplasia. Likewise, vascular remodeling was blunted in eNOS-KO only.
  
  
  METHODS
  Our results provide the first in vivo evidence that eNOS-dependent oxidative stress is unlikely to be an initial cause of impaired endothelium-dependent vasodilation and/or a pathologic factor promoting intimal hyperplasia. These findings highlight the importance of other sources of vascular oxidative stress in cardiovascular disease.
  
  
  CONCLUSIONS
  eNOS-dependent oxidative stress is unlikely to induce functional vascular damage as long as concomitant generation of NO is preserved. This underlines the importance of current and new therapeutic strategies in improving endothelial NO generation.
authors.affiliation: 1 Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University , Düsseldorf, Germany .
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Suvorava
authors.affiliation: 1 Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University , Düsseldorf, Germany .
authors.forename: Nadine
authors.initials: N
authors.lastname: Nagy
authors.affiliation: 1 Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University , Düsseldorf, Germany .
authors.forename: Stephanie
authors.initials: S
authors.lastname: Pick
authors.affiliation: 2 Institute for Animal Developmental and Molecular Biology, Heinrich-Heine-University , Düsseldorf, Germany .
authors.forename: Oliver
authors.initials: O
authors.lastname: Lieven
authors.affiliation: 2 Institute for Animal Developmental and Molecular Biology, Heinrich-Heine-University , Düsseldorf, Germany .
authors.forename: Ulrich
authors.initials: U
authors.lastname: Rüther
authors.affiliation: 1 Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University , Düsseldorf, Germany .
authors.forename: Vu Thao-Vi
authors.initials: VT
authors.lastname: Dao
authors.affiliation: 1 Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University , Düsseldorf, Germany .
authors.forename: Jens W
authors.initials: JW
authors.lastname: Fischer
authors.affiliation: 3 Division of Cardiology, Emory University School of Medicine , Atlanta, Georgia .
authors.forename: Martina
authors.initials: M
authors.lastname: Weber
authors.affiliation: 1 Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University , Düsseldorf, Germany .
authors.forename: Georg
authors.initials: G
authors.lastname: Kojda
mesh_terms: D000409:Alanine / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000378:metabolism; D002417:Cattle; D002956:Citrulline / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009206:Myocardium / Q000378:metabolism; D058426:Neointima / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D013481:Superoxides / Q000378:metabolism; D014664:Vasodilation
chemical_list: D013481:Superoxides; D002956:Citrulline; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D003545:Cysteine; D000409:Alanine