PT - JOURNAL ARTICLE AU - Maxim Wilkinson AU - Robert Maidstone AU - Andrew Loudon AU - John Blaikley AU - Iain R. White AU - Dave Singh AU - David W. Ray AU - Royston Goodacre AU - Stephen J. Fowler AU - Hannah J. Durrington TI - Circadian rhythm of exhaled biomarkers in health and asthma AID - 10.1183/13993003.01068-2019 DP - 2019 Jan 01 TA - European Respiratory Journal PG - 1901068 4099 - http://erj.ersjournals.com/content/early/2019/06/04/13993003.01068-2019.short 4100 - http://erj.ersjournals.com/content/early/2019/06/04/13993003.01068-2019.full AB - Question addressed Circadian rhythms control many biological processes in the body in both health and disease. Greater understanding of diurnal variability in disease related biomarkers is crucial for their application in clinical practice and biomarkers of circadian rhythm are required to facilitate further research into disturbed chronicity. To determine if fractional exhaled nitric oxide and breath volatile biomarkers vary rhythmically during the day in healthy and asthmatic individuals.Methods Ten individuals with moderate, atopic asthma (on regular inhaled corticosteroids) and 10 healthy volunteers (all non-smokers) completed an overnight visit where their exhaled breath volatiles and forced exhaled nitric oxide levels were collected every 6 h. Breath volatiles were analysed using gas chromatography mass spectrometry, after trapping these volatiles on sorbent materials for thermal desorption.Results Nine breath volatiles (including acetone and isoprene) exhibit diurnal variation across all individuals. Furthermore the circadian pattern of several VOCs is altered in individuals with asthma and fractional exhaled nitric oxide is rhythmic in asthma but not in healthy controls.Conclusions Markers of circadian rhythm can be identified in breath and may offer insight into circadian profiling to help treat disease. Additionally this work suggests that time of day must be controlled when designing future biomarker discovery studies. Further work is required with larger cohorts to validate and extend these findings.FootnotesThis manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.Conflict of interest: Mr Wilkinson reports no conflicts of interest.Conflict of interest: Dr. Maidstone has nothing to disclose.Conflict of interest: Dr. Loudon has nothing to disclose.Conflict of interest: Dr. Blaikley reports grants from Medical Research Council, during the conduct of the study; .Conflict of interest: Dr. White has nothing to disclose.Conflict of interest: Dr. Singh reports grants and personal fees from AstraZeneca, grants and personal fees from Boehringer Ingelheim, grants and personal fees from Chiesi, personal fees from Cipla, personal fees from Genentech, grants and personal fees from GlaxoSmithKline, grants and personal fees from Glenmark, grants and personal fees from Menarini, grants and personal fees from Mundipharma, grants and personal fees from Novartis, personal fees from Peptinnovate, grants and personal fees from Pfizer, grants and personal fees from Pulmatrix, grants and personal fees from Therevance, grants and personal fees from Verona, outside the submitted work.Conflict of interest: Dr. Ray has nothing to disclose.Conflict of interest: Dr. Goodacre has nothing to disclose.Conflict of interest: Dr. Fowler reports personal fees and non-financial support from AstraZeneca, grants and personal fees from Boehringer Ingelheim, personal fees from Novartis, personal fees from Teva, personal fees from Chiesi, outside the submitted work.Conflict of interest: Dr. Durrington has nothing to disclose.