title: Effect of N-acetylcysteine supplementation on oxidative stress status and alveolar inflammation in people exposed to asbestos: a double-blind, randomized clinical trial.
abstract: OBJECTIVE
  Many of the pathological consequences in the lung following inhalation of asbestos fibres arise as a consequence of persistent oxidative stress and inflammation. Inflammatory responses can be observed in asymptomatic asbestos-exposed individuals. There are currently no interventions to reduce inflammatory or oxidative responses to asbestos before disease develops. We investigated the effects of oral N-acetylcysteine (NAC) on indicators of inflammation or oxidative stress in asymptomatic people previously exposed to asbestos.
  
  
  METHODS
  A double-blind, randomized, placebo-controlled study was conducted to assess the effectiveness and safety of 1800 mg of NAC given orally over a period of 4 months. This was a proof of principle study. Effectiveness was assessed using indicators of inflammation or oxidation as primary end-points. Serum levels of total combined thiols (cysteine, cysteinylglycine, glutathione and homocysteine) were used to monitor the NAC supplementation.
  
  
  RESULTS
  Thirty-four subjects were randomly allocated to NAC and 32 to placebo. Serum levels of total combined thiols were similar between the groups after intervention. There were no differences in levels of inflammatory or oxidative stress end-points between the groups. No adverse effects were identified.
  
  
  CONCLUSIONS
  No evidence was found that NAC supplementation replenishes total combined thiols in the blood of healthy subjects with a history of asbestos exposure. There was also no evidence of reduced indicators of inflammation or oxidative stress. Further studies should determine the conditions required to increase levels of total anti-oxidant capacity in the blood and in the lungs of subjects with either asbestos-related diseases or subclinical lung inflammation.
authors.affiliation: School of Population Health, University of Western Australia, Perth, Western Australia, Australia.|School of Public Health, Curtin University, Perth, Western Australia, Australia.
authors.forename: Helman
authors.initials: H
authors.lastname: Alfonso
authors.affiliation: School of Population Health, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Franklin
authors.affiliation: Department of Clinical Biochemistry, Path West Laboratory Medicine, Perth, Western Australia, Australia.
authors.forename: Simon
authors.initials: S
authors.lastname: Ching
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Kevin
authors.initials: K
authors.lastname: Croft
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Phil
authors.initials: P
authors.lastname: Burcham
authors.affiliation: School of Population Health, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Nola
authors.initials: N
authors.lastname: Olsen
authors.affiliation: School of Population Health, University of Western Australia, Perth, Western Australia, Australia.|Centre for Medical Research, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Alison
authors.initials: A
authors.lastname: Reid
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Joyce
authors.affiliation: School of Population Health, University of Western Australia, Perth, Western Australia, Australia.|Institute of Child Health Research, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Nick
authors.initials: N
authors.lastname: de Klerk
authors.affiliation: School of Population Health, University of Western Australia, Perth, Western Australia, Australia.|School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia.|Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
authors.forename: Aw Bill
authors.initials: AB
authors.lastname: Musk
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage*; D000368:Aged; D001194:Asbestos / Q000009:adverse effects*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D016166:Free Radical Scavengers / Q000008:administration & dosage; D006801:Humans; D007249:Inflammation / Q000188:drug therapy / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D018384:Oxidative Stress / Q000187:drug effects*; D011014:Pneumonia / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D016166:Free Radical Scavengers; D001194:Asbestos; D000111:Acetylcysteine
keywords: asbestos-induced lung disease; interstitial fibrosis; occupational lung disease; oxidative stress