title: Oxidized vitamin E and glutathione as markers of clinical status in asthma.
abstract: OBJECTIVE
  Antioxidant status is disturbed in asthma. Measurement of both oxidized and reduced forms of antioxidants provides important information regarding the oxidant/antioxidant balance. The aim of this study was to investigate the clinical relevance of key antioxidants (alpha-tocopherol and glutathione) in asthma, by measuring the oxidized and reduced forms, in the airways (induced sputum) and systemically (peripheral blood).
  
  
  METHODS
  This cross-sectional study examines stable asthmatics (n=44) and healthy controls (n=31) recruited through John Hunter Hospital, NSW, Australia. We collected peripheral blood and induced sputum during hypertonic saline challenge. Alpha-tocopherol and alpha-tocopherol quinone were measured by HPLC. Total glutathione and glutathione disulfide were determined by a colorimetric assay.
  
  
  RESULTS
  Plasma alpha-tocopherol was low in asthma versus controls. Subjects with asthma had higher levels of whole blood alpha-tocopherol quinone and %alpha-tocopherol quinone than controls and %alpha-tocopherol quinone correlated with asthma control (p=0.009). Sputum supernatant levels of total, reduced and oxidized glutathione were elevated in asthma versus controls. Oxidized glutathione in sputum supernatant negatively correlated with FEV(1)/FVC% (p=0.029).
  
  
  CONCLUSIONS
  In asthma, both systemic and airway antioxidant defences are disturbed. Oxidized forms of alpha-tocopherol and glutathione are associated with clinical asthma outcomes, and should be further investigated as a tool for monitoring asthma.
authors.affiliation: Department of Respiratory and Sleep Medicine, Level 3, Hunter Medical Research Institute, John Hunter Hospital, Locked Bag 1, Hunter Region Mail Centre, Newcastle, 2310 NSW, Australia. lisa.wood@newcastle.edu.au
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Wood
authors.forename: Manohar L
authors.initials: ML
authors.lastname: Garg
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Blake
authors.forename: Jodie L
authors.initials: JL
authors.lastname: Simpson
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gibson
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D001249:Asthma / Q000097:blood / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D003124:Colorimetry; D003430:Cross-Sectional Studies; D005260:Female; D005978:Glutathione / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D013183:Sputum / Q000737:chemistry*; D014810:Vitamin E / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D014810:Vitamin E; D005978:Glutathione