Exhaled breath contains thousands of volatile organic compounds (VOCs) that reflect the metabolic process occurring in the host both locally in the airways and systemically. They also arise from the environment and the airway microbiome. Comprehensive analysis of breath VOCs (breathomics) provides opportunities for non-invasive biomarker discovery and novel mechanistic insights.
Applications in obstructive lung diseases, such as asthma and COPD, include not only diagnostics (especially in children and other challenging diagnostic areas) but also the identification of clinical treatable traits such as airway eosinophilia and risk of infection/exacerbation that are not specific to diagnostic labels. Whilst many aspects of breath sampling and analysis are challenging, proof of concept studies with mass-spectrometry and electronic noses technologies have provided independent studies with moderate to good diagnostic- and phenotypic accuracies.
The present review evaluates the data obtained by breathomics in:
- predicting the inception of asthma or COPD,
- inflammatory phenotyping,
- predicting exacerbations
- and treatment stratification.
The current findings merit the current efforts step of large multi-centre studies, using standardized sampling, shared anaytical methods and databases, including external validation cohorts. This will position this non-invasive technology in the clinical assessment and monitoring of chronic airways diseases.
