Breathomics in Chronic Airway Diseases

Chronic airway diseases cause a large burden for patients and caregivers and have large economic impact. Moreover, the burden is expected to increase with an increasing life expectancy of the world population. Therefore, there is a need for new biomarkers that can guide diagnosis, monitoring and the treatment of chronic airway diseases. Exhaled breath contains a complex mixture of volatile organic compounds (VOC) that can reflect local, systemic and exogenous (patho)physiological processes in the airways and alveoli and may thus be a promising target for biomarker discovery. Furthermore, breathomics holds the potential for non-invasive, easy, safe and point-of-care analysis. Several techniques for exhaled breath analysis exist that can be distinguished by three main aspects; the ability to detect individual VOCs or VOC patterns, real-time or offline measurements, and targeted or untargeted approaches. Available techniques have different advantages and limitations regarding sensitivity, specificity, costs and complexity. Multiple clinical studies already show the many opportunities of exhaled breath analysis regarding disease diagnosis, monitoring and prediction in diseases like asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF). To allow for implementation of exhaled breath in clinical practice, limitations of current detection techniques (e.g., the need for highly specialized personnel and machinery or sensitivity to detect very low concentrations of molecules in exhaled breath) should be overcome and results should be validated. Breathomics has large potential to make more personalized treatment possible in chronic airway diseases.