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Investigation of faecal volatile organic metabolites as novel diagnostic biomarkers in inflammatory bowel disease
Author(s) -
Ahmed I.,
Greenwood R.,
Costello B.,
Ratcliffe N.,
Probert C. S.
Publication year - 2016
Publication title -
alimentary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.308
H-Index - 177
eISSN - 1365-2036
pISSN - 0269-2813
DOI - 10.1111/apt.13522
Subject(s) - inflammatory bowel disease , ulcerative colitis , gastroenterology , medicine , feces , metabolomics , dysbiosis , crohn's disease , disease , chromatography , chemistry , biology , microbiology and biotechnology
Summary Background The aetiology of inflammatory bowel disease ( IBD ) remains poorly understood. Recent evidence suggests an important role of gut microbial dysbiosis in IBD , and this may be associated with changes in faecal volatile organic metabolites ( VOM s). Aim To describe the changes in the faecal VOM s of patients with IBD and establish their diagnostic potential as non‐invasive biomarkers. Methods Faecal samples were obtained from 117 people with Crohn's disease ( CD ), 100 with ulcerative colitis ( UC ), and 109 healthy controls. Faecal VOM s were extracted using solid‐phase micro‐extraction and analysed by gas chromatography mass spectrometry. Data analysis was carried out using partial least squares‐discriminate analysis ( PLS ‐ DA ) to determine class membership based on distinct metabolomic profiles. Results The PLS ‐ DA model showed clear separation of active CD from inactive disease and healthy controls ( P < 0.001). Heptanal, 1‐octen‐3‐ol, 2‐piperidinone and 6‐methyl‐2‐heptanone were up‐regulated in the active CD group [variable important in projection ( VIP ) score 2.8, 2.7, 2.6 and 2.4, respectively], while methanethiol, 3‐methyl‐phenol, short‐chain fatty acids and ester derivatives were found to be less abundant ( VIP score of 3.5, 2.6, 1.5 and 1.2, respectively). The PLS ‐ DA model also separated patients with small bowel CD from healthy controls and those with colonic CD from UC ( P < 0.001). In contrast, less distinct separation was observed between active UC , inactive UC and healthy controls. Conclusions Analysis of faecal volatile organic metabolites can provide an understanding of gut metabolomic changes in IBD . It has the potential to provide a non‐invasive means of diagnosing IBD , and can differentiate between UC and CD .