How gut bacteria breaking down tryptophan may drive inflammatory arthritis
Official title: Influence of bacterial tryptophan metabolism on inflammatory arthritis
Funded at University of Colorado Denver · NIH-11166419 · Data updated 2026-11-12
This project looks at whether gut bacteria that convert the amino acid tryptophan into indole compounds promote inflammation in people with rheumatoid arthritis and spondyloarthritis.
Quick facts
| Grant type | R01 grant |
|---|---|
| Study type | NIH-funded research |
| Funding institution | University of Colorado Denver NIH-funded |
| Lab location | 1 site (Aurora, UNITED STATES) |
| Project start | April 10, 2019 |
| Project end | July 31, 2029 |
| Funding year | 2025 |
| Award (this year) | $423,552 |
| NIH project number | 5R01AR075033-07 |
| Project ID | NIH-11166419 on NIH RePORTER |
Who could benefit from this research
✓Could help
People with rheumatoid arthritis or axial spondyloarthritis, and individuals considered at high risk for these autoimmune diseases, are the kinds of patients whose samples and immune responses are being studied.
✕Less likely to help
People with non-autoimmune joint conditions such as osteoarthritis or those whose disease is unrelated to gut microbial metabolism may not benefit from these findings.
What this research studies
Researchers compare gut microbes and metabolites from people with rheumatoid arthritis or axial spondyloarthritis to find bacteria that make indoles from tryptophan. They study human intestinal tissue, antibodies, and T cells to see immune reactions tied to those bacteria. In parallel, they use mouse models to test whether indole-producing bacteria, indole supplementation, low-tryptophan diets, or antibiotics change joint inflammation. The team will examine how indoles affect intestinal dendritic cells and Th17 cells and how that influences autoantibody-driven disease.
Why it matters
Potential benefit: If successful, this work could point to gut-targeted approaches (diet changes, microbiome therapies, or drugs) to prevent or reduce inflammatory joint damage in RA and spondyloarthritis.
How similar studies have gone: Previous human-sample and animal-model work has linked the gut microbiome to inflammatory arthritis and mouse studies support a role for indole, but translating these findings into human treatments is still early and novel.
Where this research is happening
-
University of Colorado Denver
Aurora, United States Active
Researchers
- Principal investigator: Kuhn, Kristine a. — University of Colorado Denver
- Study coordinator: Kuhn, Kristine a.
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About this research
- This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
- Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
- For full project details, budget, and progress reports, visit the official NIH RePORTER page.