title: Relationships between adult asthma and oxidative stress markers and pH in exhaled breath condensate: a systematic review.
abstract: Oxidative stress has a recognized role in the pathophysiology of asthma. Recently, interest has increased in the assessment of pH and airway oxidative stress markers. Collection of exhaled breath condensate (EBC) and quantification of biomarkers in breath samples can potentially indicate lung disease activity and help in the study of airway inflammation, and asthma severity. Levels of oxidative stress markers in the EBC have been systematically evaluated in children with asthma; however, there is no such systematic review conducted for adult asthma. A systematic review of oxidative stress markers measured in EBC of adult asthma was conducted, and studies were identified by searching MEDLINE and SCOPUS databases. Sixteen papers met the inclusion criteria. Concentrations of exhaled hydrogen ions, nitric oxide products, hydrogen peroxide and 8-isoprostanes were generally elevated and related to lower lung function tests in adults with asthma compared to healthy subjects. Assessment of EBC markers may be a noninvasive approach to evaluate airway inflammation, exacerbations, and disease severity of asthma, and to monitor the effectiveness of anti-inflammatory treatment regimens. Longitudinal studies, using standardized analytical techniques for EBC collection, are required to establish reference values for the interpretation of EBC markers in the context of asthma.
authors.affiliation: Allergy and Lung Health Unit, The University of Melbourne, Melbourne, Australia.|Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
authors.forename: F M
authors.initials: FM
authors.lastname: Aldakheel
authors.affiliation: Department of Respiratory Medicine and Prince of Wales Hospital Clinical School, University of New South Wales, Sydney, Australia.
authors.forename: P S
authors.initials: PS
authors.lastname: Thomas
authors.affiliation: Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Australia.
authors.forename: J E
authors.initials: JE
authors.lastname: Bourke
authors.affiliation: Allergy and Lung Health Unit, The University of Melbourne, Melbourne, Australia.|Murdoch Childrens Research Institute, Melbourne, Australia.
authors.forename: M C
authors.initials: MC
authors.lastname: Matheson
authors.affiliation: Allergy and Lung Health Unit, The University of Melbourne, Melbourne, Australia.|Murdoch Childrens Research Institute, Melbourne, Australia.
authors.forename: S C
authors.initials: SC
authors.lastname: Dharmage
authors.affiliation: Allergy and Lung Health Unit, The University of Melbourne, Melbourne, Australia.|Murdoch Childrens Research Institute, Melbourne, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Lowe
mesh_terms: D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000453:epidemiology / Q000378:metabolism* / Q000628:therapy; D015415:Biomarkers; D001944:Breath Tests / Q000379:methods; D045853:Exhalation; D005163:Factor Analysis, Statistical; D006801:Humans; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D009569:Nitric Oxide; D018384:Oxidative Stress; D015995:Prevalence; D066232:Pulmonary Elimination; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide; D006861:Hydrogen Peroxide
keywords: asthma; exhaled breath condensate; oxidative stress; pH; reactive oxygen species