# Fecal microbiota, short chain fatty acids, bile acids, and colonic transit in Irritable Bowel Syndrome

> **NIH NIH K23** · INDIANA UNIVERSITY INDIANAPOLIS · 2021 · $180,481

## Abstract

PROJECT SUMMARY
The precise mechanisms by which the gut microbiome and contributes to irritable bowel syndrome (IBS)
symptoms are unclear. However , it is recognized that microbial metabolites such as short chain fatty acids
(SCFA) and bile acids exert important effects on gastrointestinal physiology. Thus, an enhanced understanding
of the relationships between the gut microbiome, SCFAs, and bile acids will be essential to developing novel
strategies for effective IBS treatment. This career development application is submitted on response to PA-18-
374 in which the candidate proposes a hypothesis-driven research strategy to (1) identify changes in the fecal
microbiota that are associated with SCFA and bile acid profiles in IBS, (2) establish SCFAs as an actionable IBS
biomarker, and (3) interrogate interactions between SCFA and bile acids in IBS. This proposal builds on
preliminary data acquired through the support of an institutional KL2. The specific aims of this research strategy
are to (1) identify shifts in the relative abundance of SCFA-producing bacteria that are associated with fecal
SCFA levels, markers of SCFA production through inulin fermentation (residual fecal inulin after inulin challenge),
and colonic transit in IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), and controls and (2) identify shifts
in the relative abundance of bile acid dehydroxylating bacteria that are associated with fecal bile acids and
markers of SCFA production in IBS-C, IBS-D, and controls and test if bile acid profiles are associated with
markers of SCFA production. To achieve these aims, the candidate will develop a prospective cohort of well-
phenotyped IBS patients and matched-controls who will undergo (1) baseline assessments of their fecal
microbiota, fecal SCFAs, fecal bile acids, and colonic transit, followed by (2) repeat assessments of fecal
microbiota, fecal SCFAs, fecal bile acids, as well as measurement of fecal inulin after standardized dietary
intervention with inulin supplementation. The proposed career development plan integrates in-depth mentoring
from a multidisciplinary team of senior scientists, advanced coursework in bioinformatics and microbiome
analysis, experiential learning through the conduct of the proposed research, and a highly supportive research
environment. The mentorship team, which includes independent investigators with expertise in clinical and
translational research in microbiome science (Nelson) and functional gastrointestinal disorders (Camilleri); data
analysis and biostatistics (Xu); bioinformatics (Dong); and career development (Chalasani) will guide the
candidate's research and career development. The superb institutional infrastructure for facilitating junior
investigators and substantial institutional commitment greatly strengthen this application. At the conclusion of
the program, the candidate will be well positioned to become an independent physician investigator studying
novel microbial and metabolomic...

## Key facts

- **NIH application ID:** 10158484
- **Project number:** 5K23DK122015-03
- **Recipient organization:** INDIANA UNIVERSITY INDIANAPOLIS
- **Principal Investigator:** Andrea Shin
- **Activity code:** K23 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $180,481
- **Award type:** 5
- **Project period:** 2019-08-13 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10158484

## Citation

> US National Institutes of Health, RePORTER application 10158484, Fecal microbiota, short chain fatty acids, bile acids, and colonic transit in Irritable Bowel Syndrome (5K23DK122015-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10158484. Licensed CC0.

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