Noninvasive Quantification of Volatile Metabolites in Breath: A Potential Indicator of Inflammatory Bowel Diseases Activity

Abstract

All tests currently used in clinical diagnostics and the activity monitoring of inflammatory bowel disease (IBD) have limited sensitivity and specificity or are directly linked to discomfort or risk to the patient (endoscopy or repeated CT tests), therefore necessitating new, non-invasive methods. The quantification of volatile metabolites in breath is a potential biomarker of IBD presence and activity.

Selected ion flow tube mass spectrometry (SIFT-MS) is a relatively new analytical technique for quantitative analysis of the tracegases, chiefly in human breath. In our pilot project, SIFT-MS was used for the analysis of volatile IBD biomarkers in breath.

Differences in their concentrations were studied in relation to the presence of IBD and activity of the disease. The study sample was composed of 48 IBD patients, 28 with ulcerative colitis (UC) and 20 with Crohn’s disease (CD).

Of the 48 patients, 25 were female and 23 male. The mean age was 30 years and disease duration 10 years.

Significant differences between subgroups of patients were found in the concentrations of pentane, carbon disulphide, acetone and propanol. Patients with CD (both with active and quiescent disease) had significantly higher concentrations of pentane compared to the group of healthy individuals (115 vs. 61 nmol/mol;p < 0.01), as was the case for patients with active UC (91 vs. 61 nmol/mol; p < 0.01).

The concentration of carbon disulphide (H2S) was significantly higher in patients with active CD (111 vs. 50 nmol/mol; p < 0.01) and concentrations of acetone (1,495 vs. 509 nmol/mol; p < 0.01) and propanol were significantly higher in the breath of patients who had undergone colonoscopy prior to breath analysis (this was likely due to a lack of nutrition). Based on the results of this study, we consider the use of breath testing using SIFT-MS to be a beneficial non-invasive diagnostic and monitoring method for IBD activity.

Further targeted studies are necessary to address this issue.