Volatiles in Exhaled Breath and Blood in Crohn's Disease: Validation Cohort

In the recent study(doi: 10.1097/Mib.0000000000000436) it was shown the potential of analysis of exhaled air to differentiate active and inactive state of Crohn's Disease (CD). Although, the molecules found in this cohort have shown potential to differentiate between CD patients in remission or with active disease, the validation of the outcomes has to be performed in new population. One crucial pathophysiologic factor in CD is excessive lipid peroxidation during oxidative stress, i.e. during overproduction of oxidants compared to the protective antioxidants. Oxidative stress is a potential aetiological factor and/or a triggering factor in CD. Many volatile compounds including hydrocarbons and aldehydes are produced during oxidative stress and they can be non-invasively measured in exhaled air 5, 6. However, exhaled breath contains volatile metabolites originating from previous or current uptake of environmental contaminants, and more interestingly from metabolism of foreign organisms (bacteria, viruses, fungi or yeasts). Therefore, it is important to study not only exhaled air but also blood in which blood borne volatile molecules can be measured. Since the current study also aims for validating the use of volatile molecules in exhaled air as non-invasive markers for disease activity in CD patients, the investigators will compare the outcome of exhaled air analysis with currently established non-invasive measure of disease activity, i.e. fecal calprotectin.