1. Changes in exhaled volatile organic compounds following indirect bronchial challenge in suspected asthmaAdam Peel, Ran Wang, Waqar Ahmed, Iain R. White, Maxim Wilkinson, Yoon K. Loke, Andrew M. Wilson, Stephen J. Fowler, 2023, original scientific article 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: asthma, exhaled volatile organic compounds, pulmonology, breath metabolomics
Published in RUNG: 31.07.2023; Views: 874; Downloads: 3
 Link to file |
2. Breath and plasma metabolomics to assess inflammation in acute strokeWaqar Ahmed, Iain R. White, Maxim Wilkinson, Craig Johnson, Nicholas J. W. Rattray, Amit K. Kishore, Royston Goodacre, Craig J. Smith, Stephen J. Fowler, 2021, original scientific article Abstract: Inflammation is strongly implicated in both injury and repair processes occurring after stroke. In this exploratory study we assessed the feasibility of repeated sampling of exhaled volatile organic compounds and performed an untargeted metabolomic analysis of plasma collected at multiple time periods after stroke. Metabolic profiles were compared with the time course of the inflammatory markers C-reactive protein (CRP) and interleukin-6 (IL-6). Serial breath sampling was well-tolerated by all patients and the measurement appears feasible in this group. We found that exhaled decanal tracks CRP and IL-6 levels post-stroke and correlates with several metabolic pathways associated with a post-stroke inflammatory response. This suggests that measurement of breath and blood metabolites could facilitate development of novel therapeutic and diagnostic strategies. Results are discussed in relation to the utility of breath analysis in stroke care, such as in monitoring recovery and complications including stroke associated infection.
Keywords: stroke, metabolomics, breath, VOCs, inflammation
Published in RUNG: 18.11.2021; Views: 1699; Downloads: 62
Link to full text
This document has many files! More... |
3. Untargeted molecular analysis of exhaled breath as a diagnostic test for ventilator-associated lower respiratory tract infections (BreathDx)Pouline M. van Oort, Tamara M. E. Nijsen, Iain R. White, Hugo Knobel, Timothy Felton, Nicholas J. W. Rattray, Oluwasola Lawal, Murtaza Bulut, Waqar Ahmed, Antonio Artigas, 2021, short scientific article Abstract: Patients suspected of ventilator-associated lower respiratory tract infections (VA-LRTIs) commonly receive broad-spectrum antimicrobial therapy unnecessarily. We tested whether exhaled breath analysis can discriminate between patients suspected of VA-LRTI with confirmed infection, from patients with negative cultures. Breath from 108 patients suspected of VA-LRTI was analysed by gas chromatography-mass spectrometry. The breath test had a sensitivity of 98% at a specificity of 49%, confirmed with a second analytical method. The breath test had a negative predictive value of 96% and excluded pneumonia in half of the patients with negative cultures. Trial registration number: UKCRN ID number 19086, registered May 2015.
Keywords: ventilator-associated pneumonia, breath analysis, volatile organic compounds, metabolomics, intensive care, hospital acquired infections
Published in RUNG: 07.09.2021; Views: 4157; Downloads: 0
This document has many files! More... |
4. Breathomics and its Application for Disease Diagnosis: A Review of Analytical Techniques and ApproachesDavid J Beale, Oliver A H Jones, Avinash V Karpe, Ding Y Oh, Iain R. White, Konstantinos A Kouremenos, Enzo A Palombo, 2018, independent scientific component part or a chapter in a monograph Abstract: The application of metabolomics to an ever-greater variety of sample types is a key focus of systems biology research. Recently, there has been a strong focus on applying these approaches toward the rapid analysis of metabolites found in non-invasively acquired samples, such as exhaled breath (also known as ‘breathomics’). The sampling process involved in collecting exhaled breath is nonintrusive and comparatively low-cost. It uses a series of globally approved methods and provides researchers with easy access to the metabolites secreted by the human body. Owing to its accuracy and rapid nature, metabolomic analysis of breath is a rapidly growing field that has proven effective in detecting and diagnosing the early stages of numerous diseases and infections. This review discusses the various collection and analysis methods currently applied in breathomics research. Some of the salient research completed in this field to date is also assessed and discussed in order to provide a basis for possible future scientific directions.
Keywords: Metabolomics, breath research, VOCs, breathomics
Published in RUNG: 22.07.2019; Views: 3156; Downloads: 0
This document has many files! More... |
