| Title: | Changes in exhaled volatile organic compounds following indirect bronchial challenge in suspected asthma |
| Author(s): | Peel A; Wang R; Ahmed W; White I; Wilkinson M; Loke YK; Wilson AM; Fowler SJ; |
| Address: | "Respiratory medicine, Norfolk Community Health and Care NHS Trust, Norwich, Norfolk, UK. Division of Immunology, Immunity to infection & Respiratory Medicine, School of Biological Sciences, The University of Manchester, Manchester, UK. Department of Respiratory Medicine, Manchester University NHS Foundation Trust, Manchester, UK. Laboratory for Environmental and Life Sciences, University of Nova Gorica, Nova Gorica, Slovenia. Norwich Medical School, University of East Anglia, Norwich, Norfolk, UK. Department of Respiratory Medicine, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich, UK. Division of Immunology, Immunity to infection & Respiratory Medicine, School of Biological Sciences, The University of Manchester, Manchester, UK stephen.fowler@manchester.ac.uk" |
| DOI: | 10.1136/thorax-2022-219708 |
| ISSN/ISBN: | 1468-3296 (Electronic) 0040-6376 (Linking) |
| Abstract: | "BACKGROUND: Inhaled mannitol provokes bronchoconstriction via mediators released during osmotic degranulation of inflammatory cells, and, hence represents a useful diagnostic test for asthma and model for acute attacks. We hypothesised that the mannitol challenge would trigger changes in exhaled volatile organic compounds (VOCs), generating both candidate biomarkers and novel insights into their origin. METHODS: Participants with a clinical diagnosis of asthma, or undergoing investigation for suspected asthma, were recruited. Inhaled mannitol challenges were performed, followed by a sham challenge after 2 weeks in participants with bronchial hyper-responsiveness (BHR). VOCs were collected before and after challenges and analysed using gas chromatography-mass spectrometry. RESULTS: Forty-six patients (mean (SD) age 52 (16) years) completed a mannitol challenge, of which 16 (35%) were positive, and 15 of these completed a sham challenge. Quantities of 16 of 51 identified VOCs changed following mannitol challenge (p<0.05), of which 11 contributed to a multivariate sparse partial least square discriminative analysis model, with a classification error rate of 13.8%. Five of these 16 VOCs also changed (p<0.05) in quantity following the sham challenge, along with four further VOCs. In patients with BHR to mannitol distinct postchallenge VOC signatures were observed compared with post-sham challenge. CONCLUSION: Inhalation of mannitol was associated with changes in breath VOCs, and in people with BHR resulted in a distinct exhaled breath profile when compared with a sham challenge. These differentially expressed VOCs are likely associated with acute airway inflammation and/or bronchoconstriction and merit further investigation as potential biomarkers in asthma" |
| Keywords: | Humans Middle Aged *Volatile Organic Compounds *Asthma/diagnosis Bronchial Provocation Tests Biomarkers/analysis Mannitol Breath Tests/methods asthma; |
| Notes: | "MedlinePeel, Adam Wang, Ran Ahmed, Waqar White, Iain Wilkinson, Maxim Loke, Yoon K Wilson, Andrew M Fowler, Stephen J eng England 2023/07/27 Thorax. 2023 Oct; 78(10):966-973. doi: 10.1136/thorax-2022-219708. Epub 2023 Jul 26" |
