Fecal Metabolome and the Intestinal Microbiota in Irritable Bowel Syndrome

There is emerging evidence that alterations in bile acids and SCFA associated with IBS could
be associated with changes in the gut microbiota. In addition to modulating levels of
intraluminal organic acids, it has been hypothesized that gut microbiota may alter local
immune responses, modulate visceral pain responses, and impair gut barrier function.

Our overall goal is to investigate the relationship between fecal bile acids, SCFA and the
gut microbiota in IBS. Results of this pilot study could reveal insights into the interplay
of the gut microbiota and small molecule mediators of IBS to suggest targeted clinical
strategies for improved diagnosis and management of this important syndrome.

AIM 1: Test the hypothesis that fecal organic acids (SFCA and bile acids) and fecal
microbiota play an important role in IBS.

AIM 2: Test the hypothesis that there is association between colonic transit and fecal
microbiota in IBS

Inclusion Criteria:

- Patients with IBS, ages 18-65 fulfilling Rome IV criteria and asymptomatic controls
with no prior history of GI disease or symptoms.

- Participants should be on a stable and consistent diet regimen and should not be
following an extreme diet intervention such as gluten-free or a low FODMAP diet at the
time of study participation.

Exclusion Criteria:

- Participants with microscopic/lymphocytic/collagenous colitis, inflammatory bowel
disease, celiac disease, visceral cancer, chronic infectious disease,
immunodeficiency, uncontrolled thyroid disease, history of liver disease or history of
elevated AST/ALT > 2.0x the upper limit of normal

- Prior radiation therapy of the abdomen or abdominal surgeries with the exception of
appendectomy or cholecystectomy > 6 months prior to study initiation

- Ingestion of any prescription, over the counter, or herbal medications which can
affect GI transit or study interpretation (e.g. opioids, narcotics, anticholinergics,
norepinephrine reuptake inhibitors, nonsteroidal anti-inflammatory drugs, COX-2
inhibitors, bile acid sequestrants) within 6 months of study initiation for
asymptomatic volunteers or within 2 days before study initiation for IBS patients

- Any females who are pregnant or trying to become pregnant or breast-feeding

- Antibiotic usage within 3 months prior to study participation

- Prebiotic or probiotic usage within the 2 weeks prior to study initiation

- Use of tobacco products within the past 6 months.