title: Plasma cysteine and glutathione are independent markers of postmethionine load endothelial dysfunction.
abstract: OBJECTIVE
  Oxidative stress caused by acute hyperhomocysteinemia impairs endothelial function in human arteries. We sought to identify markers of endothelial dysfunction during methionine-induced hyperhomocysteinemia.
  
  
  METHODS
  35 subjects underwent flow-mediated dilation (FMD) of the brachial artery by high-resolution ultrasonography and fasting blood samples before and 3 h postmethionine load (PML). Clinical, conventional biochemical, and redox status (plasma total and reduced homocysteine, glutathione, cysteine, cysteinylglycine, ascorbic acid, alpha-tocopherol, free malondialdehyde, blood glutathione) data were sequentially entered into an univariate and multivariate stepwise linear regression analysis to evaluate their relation with the dependent variable FMD.
  
  
  RESULTS
  Median [interquartile range] FMD decreased from 4.1% [2.8-6.3] to 3.2% [0.7-4.3] PML (P=0.02). At the multivariate analysis PML total cysteine (beta=-0.008, P=0.002) and glutathione (beta=0.21, P=0.005) were the only independent variables associated with FMD after methionine, adjusted for baseline FMD.
  
  
  CONCLUSIONS
  Elevated plasma total cysteine and decreased plasma total glutathione levels were associated with abnormal FMD PML. Cysteine and glutathione are stronger markers of endothelial dysfunction than clinical and all other biochemical variables explored.
authors.affiliation: CNR Clinical Physiology Institute-Milan, Department of Cardiology, Niguarda Ca' Granda Hospital, Milan, Italy. ifcnig@tin.it
authors.forename: Oberdan
authors.initials: O
authors.lastname: Parodi
authors.forename: Benedetta
authors.initials: B
authors.lastname: De Chiara
authors.forename: Damiano
authors.initials: D
authors.lastname: Baldassarre
authors.forename: Marina
authors.initials: M
authors.lastname: Parolini
authors.forename: Raffaele
authors.initials: R
authors.lastname: Caruso
authors.forename: Linda
authors.initials: L
authors.lastname: Pustina
authors.forename: Guido
authors.initials: G
authors.lastname: Parodi
authors.forename: Jonica
authors.initials: J
authors.lastname: Campolo
authors.forename: Valentina
authors.initials: V
authors.lastname: Sedda
authors.forename: Francesco
authors.initials: F
authors.lastname: Baudo
authors.forename: Cesare
authors.initials: C
authors.lastname: Sirtori
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000187:drug effects; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000209:etiology; D003545:Cysteine / Q000097:blood*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005978:Glutathione / Q000097:blood*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008715:Methionine / Q000008:administration & dosage; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011379:Prognosis; D012039:Regional Blood Flow / Q000187:drug effects; D014463:Ultrasonography; D014664:Vasodilation
chemical_list: D015415:Biomarkers; D008715:Methionine; D005978:Glutathione; D003545:Cysteine