# Oxalobacter formigenes colonization and oxalate excretion in calcium oxalate kidney stone disease

> **NIH NIH R01** · UNIVERSITY OF ALABAMA AT BIRMINGHAM · 2020 · $442,131

## Abstract

Project Summary
Calcium oxalate kidney stone disease occurs in approximately 9 % of the U.S. population and contributes
significantly to health care costs. Small reductions in urinary oxalate excretion are thought to limit stone risk.
Recent studies have indicated that a lack of Oxalobacter formigenes colonization is a significant risk factor
for calcium oxalate kidney stone formation. Our Preliminary data shows that healthy human subjects lacking
O.formigenes can be readily colonized with live preparations of O.formigenes. This ability to colonize
individuals offers a powerful means of assessing responses to varying diets before and after colonization. It
is still not clear under what conditions O.formigenes modifies stone risk, and much still needs to be learned
about how this organism establishes and maintains gut colonization. In the previous funding cycle
we identified in a mouse model conditions that influence the growth of O.formigenes in the gut, its
degradation of oxalate in the gut, its effects on the amount of oxalate excreted in urine and into the intestine,
and its sustainability in the absence of dietary oxalate. In this application we will extend these findings to
humans by examining individuals before and after colonization with O.formigenes. Diets controlled in their
contents of oxalate, calcium and other nutrients, including a diet ultra-low in oxalate, will be used to examine
the interaction between diet, O.formigenes colonization and urinary oxalate excretion. This proposal will use
spinach that contains carbon 13-oxalate to accurately determine whether colonization modifies the response
to an oxalate-rich meal. Continuous intravenous infusions of the stable, non-radioactive oxalate isotope, 13C2-
oxalate, before and after colonization will directly determine if gastrointestinal oxalate secretion occurs and
whether colonization influences such secretion. Recent evidence suggests individuals are colonized with
different strains and in some cases more than one strain. However, it is not known whether the biological
differences between strains influence colonization persistence and urinary oxalate excretion and this will be
examined in this application. If the specific aims are successfully completed they will provide valuable
information about the importance of O.formigenes colonization in influencing oxalate levels, will create insight
into the factors that impact O.formigenes colonization, and will help identify new strategies for modifying the
gut milieu and calcium oxalate kidney stone risk.

## Key facts

- **NIH application ID:** 9896806
- **Project number:** 5R01DK087967-09
- **Recipient organization:** UNIVERSITY OF ALABAMA AT BIRMINGHAM
- **Principal Investigator:** John Knight
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $442,131
- **Award type:** 5
- **Project period:** 2017-02-01 → 2023-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9896806

## Citation

> US National Institutes of Health, RePORTER application 9896806, Oxalobacter formigenes colonization and oxalate excretion in calcium oxalate kidney stone disease (5R01DK087967-09). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9896806. Licensed CC0.

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