Metabolomics Analysis Method Used for Diagnosis of IBD

A team of Canadian researchers used an advanced metabolomics approach to differentiate inflammatory bowel syndrome (IBS) from other related gastrointestinal disorders.

Irritable bowel syndrome (IBS), the most commonly diagnosed functional gastrointestinal (GI) disorder in developed countries, is characterized by chronic abdominal pain and altered bowel habits. Accurate and timely diagnosis of IBS is challenging as it relies on observation of symptoms and an evolving set of exclusion criteria to distinguish it from other related GI disorders such as inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis.

To develop better a better method for diagnosis of IBS, investigators at McMaster University (Montreal, Canada) used multisegment injection-capillary electrophoresis-mass spectrometry to generate metabolite profiles in repeat urine specimens collected from a cohort of 42 IBS patients and compared them to profiles from 20 healthy controls.

Results revealed ten consistently elevated urinary metabolites in repeat samples collected from IBS patients at two different time points, which were associated with greater collagen degradation and intestinal mucosal turn-over processes likely due to low-grade inflammation. IBS-specific metabolites identified in urine included a series of hydroxylysine metabolites (O-glycosylgalactosyl-hydroxylysine, O-galactosyl-hydroxylysine, lysine), mannopyranosy-l-tryptophan, imidazole propionate, glutamine, serine, ornithine, dimethylglycine, and dimethylguanosine.

While the metabolomics approach avoided invasive blood sampling, colonoscopy, and/or tissue biopsies, the investigators warned that at this time its usefulness was limited somewhat by the propensity of IBS patients to suffer from additional illnesses, including depression, and that they took more prescribed medications than did the healthy controls.

“Diagnostic testing for IBS involves a long process of excluding other related gut disorders, such as inflammatory bowel disease,” said senior author Dr. Philip Britz-McKibbin, professor of chemistry and chemical biology at McMaster University.

"We were interested in finding if there is a better way to detect and monitor IBS that avoids invasive colonoscopy procedures while also giving us better insights into its underlying mechanisms.”

The study was published in the May 20, 2019, online edition of the journal Metabolomics.

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