Longitudinal Study on Bacterial Production of LPC and LPA in Patients With Inflammatory Bowel Disease

The human body is inhabited by a complex community of microbes, collectively referred to as "microbiota". A vast majority of these bacteria are found in the lumen of the gastrontestinal tract (colon, small intestine, stomach and esophagus). Several lines of evidence indicate that changes in microbiota (bacteria) may be involved in the origin of different gastrointestinal diseases, including inflammatory Bowel Disease (IBD), with its two main types: Crohn´s disease and Ulcerative colitis.

Recent data suggest that the gut bacteria have the capability to produce lysophosphatidylcholine (LPC) and its derivative, lysophosphatidic acid (LPA), small lipid molecules that were shown previously to be involved in the genesis and maintenance of chronic pain. The investigators found that these molecules are higher in stool of patients with Inflammatory Bowel Disease (IBD), but it is unclear whether 1) they are produced by gut bacteria, and 2) whether their production underlies chronic pain in patients with IBD.

The purpose of this study is to determine whether the gut bacteria produce LPC and LPA and induce chronic abdominal pain, which is common in many patients with IBD, even when their colitis is in remission (absence of overt gut inflammation).

In this exploratory longitudinal study, the investigators will recruit patients with IBD, aged 18-70 years, of both sexes, with a history of moderate to severe chronic abdominal pain (as defined by their gastroenterologist), which persists during remission of colitis (absence of overt inflammation on CT or MRI imaging, and baseline fecal calprotectin less than 200 μg/g of stool) or while having only mild gut inflammation, defined by either colonoscopy (Endoscopic Mayo score: 0-1 or Simple Endoscopic Score for Crohn's Disease score: 0-10). We will recruit 15 patients with baseline stool LPC less that 200 μg/mg and LPA less than 100 μg/mg levels after first assessment in screening visit. Recruitment will take place at McMaster University IBD clinic (https://www.mcmasteribd.com).

After study participant meets the eligibility criteria and signs the informed consent, stool and urine samples will be collected and abdominal pain scores recorded for 3 weeks. Daily stool and urine samples (first stool of the day and morning (overnight) urine) will be collected, and LPC/LPA measured by ELISA. Abdominal pain will be assessed daily with a visual analogue scale (VAS). In addition, clinical symptoms will be evaluated by PROMIS (GI Belly Pain, Diarrhea, Constipation and Bloating) and DASS-21 questionnaires at the end of each week, as they assess symptoms during the preceding 7 days. Dietary intake will be assessed at the beginning of each week by a 3-day food diary. The clinical surveys will be provided online, using RedCap software and secure servers already operational within McMaster.