Early acidification of stool and urine as a simple noninvasive screening tool for ulcerative colitis activity

Abstract

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by recurrent inflammation of the colon. The absence of simple, noninvasive, and early biomarkers for disease onset and progression remains a major clinical challenge. This study aimed to evaluate the potential of pH values in biological samples as noninvasive indicators for the early disease-related changes in an experimental rat model of UC. Experimental colitis was induced in rats by administering dextran sulfate sodium, and the results were compared to those of healthy controls. Disease progression was monitored by evaluating disease severity scores and histopathological changes. Throughout the experimental period, stool and urinary pH were measured daily, while colonic and serum pH were assessed post-mortem. As the experiment progressed, the colitic rats exhibited marked weight loss and severe inflammatory changes in the colon. Despite the worsening disease, no significant alterations were observed in colonic or serum pH. In contrast, both stool and urinary pH values significantly decreased during the early phase of experimental colitis. However, these pH fluctuations did not consistently correlate with UC severity. In conclusion, our findings suggest that stool and urinary pH represent promising, noninvasive biomarkers for the early detection and monitoring of disease activity in UC.

Keywords

pH / Stool / Ulcerative colitis / Urine / Rat

Acknowledgments

We would like to express our sincere gratitude to the Nagahama Life Science Laboratory, Oriental Yeast Co., Ltd., Shiga, Japan, for analyzing the rat serum.

Funding

This study was supported by a Grant-in-Aid for Academic Research Promotion from Kyoto Tachibana University (2025-5).

Conflict of interest

The authors declare that they have no competing interests.

Author contributions

Conceptualization: Kohki Okada

Data curation: All authors

Formal analysis: Kohki Okada, Ruku Sasaki

Investigation: Kohki Okada, Ruku Sasaki

Methodology: Kohki Okada

Project administration: Kohki Okada

Supervision: Kohki Okada

Visualization: All authors

Writing-original draft: Kohki Okada

Writing-review & editing: Shintaro Noborio, Yugo Taoka, Kaito Yamamoto

Ethics approval and consent to participate

The animal experiments complied with the Animal Research: Reporting of In Vivo Experiments guidelines and were approved by the Animal Care and Use Committee of Kyoto Tachibana University (permission number: 22-07).

Consent for publication

Not applicable.

Availability of data

The data that support the findings of this study are available upon reasonable request from the corresponding author.

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