Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013;8(3):e58204.
doi: 10.1371/journal.pone.0058204. Epub 2013 Mar 13.

An investigation of fecal volatile organic metabolites in irritable bowel syndrome

Iftikhar Ahmed  1 , Rosemary Greenwood, Ben de Lacy Costello, Norman M Ratcliffe, Chris S Probert
Affiliations

An investigation of fecal volatile organic metabolites in irritable bowel syndrome

Iftikhar Ahmed et al. PLoS One. 2013.

Abstract

Diagnosing irritable bowel syndrome (IBS) can be a challenge; many clinicians resort to invasive investigations in order to rule out other diseases and reassure their patients. Volatile organic metabolites (VOMs) are emitted from feces; understanding changes in the patterns of these VOMs could aid our understanding of the etiology of the disease and the development of biomarkers, which can assist in the diagnosis of IBS. We report the first comprehensive study of the fecal VOMs patterns in patients with diarrhea-predominant IBS (IBS-D), active Crohn's disease (CD), ulcerative colitis (UC) and healthy controls. 30 patients with IBS-D, 62 with CD, 48 with UC and 109 healthy controls were studied. Diagnosis of IBS-D was made using the Manning criteria and all patients with CD and UC met endoscopic, histologic and/or radiologic criteria. Fecal VOMs were extracted by solid phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). 240 VOMs were identified. Univariate analysis showed that esters of short chain fatty acids, cyclohexanecarboxylic acid and its ester derivatives were associated with IBS-D (p<0.05), while aldehydes were more abundant in IBD (p<0.05). A predictive model, developed by multivariate analysis, separated IBS-D from active CD, UC and healthy controls with a sensitivity of 94%, 96% and 90%; and a specificity of 82%, 80% and 80% respectively (p<0.05). The understanding of the derivation of these VOMs may cast light on the etiology of IBS-D and IBD. These data show that fecal VOMs analyses could contribute to the diagnosis of IBS-D, for which there is no laboratory test, as well as IBD.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1
Figure 1A: A typical chromatogram from fecal headspace gas from a healthy volunteer. Figure 1B: A comparison of chromatograms from three different study groups (CD, IBS-D and healthy controls) showing absence and presence of VOMs peaks.
Figure 2
Figure 2
Figure 2A1: Statistical analysis of IBS vs. CD. AUC = 0.97. 2: Cross-validation of IBS vs. CD analysis. AUC = 0.93. Figure 2B1: Statistical analysis of IBS vs. UC. AUC = 0.96. Figure 2B2: Cross-validation of IBS vs. UC analysis. AUC = 0.88.
Figure 3
Figure 3. Box and Whisker plot of discrimination of IBS from active IBD.
Figure 4
Figure 4
Figure 4A: ROC curve for IBS vs. controls. Figure 4B: ROC curve for cross-validation.
See this image and copyright information in PMC

References

    1. Jones J, Boorman J, Cann P, Forbes A, Gornborone J, et al. (2000) British Society of Gastroenterology guidelines for the management of the irritable bowel syndrome. GUT 47: 1–19. - PMC - PubMed
    1. Williams JG, Roberts SE, Ali MF, Cheung WY, Cohen DR, et al. (2007) Gastroenterology services in the UK. The burden of disease, and the organisation and delivery of services for gastrointestinal and liver disorders: a review of the evidence. GUT 56: 1–113. - PMC - PubMed
    1. Sandler RS (1990) Epidemiology of irritable bowel syndrome in the United States. Gastroenterology 99: 409–15. - PubMed
    1. Azpiroz F, Bouin M, Camilleri M, Mayer EA, Poitras P, et al. (2007) Mechanisms of hypersensitivity in IBS and functional disorders. Neurogastroenterol Motill 19: 62–88. - PubMed
    1. Grundy D, Al-Chaer ED, Aziz Q, Collins SM, Meiyun KE, et al. (2006) Fundamentals of Neurogastroenterology: Basic Science. Gastroenterology 130(5): 1391–1411. - PubMed

Publication types

Substances