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Zhao et al. Microbiome Res Rep. 2025;4:28 Microbiome Research
DOI: 10.20517/mrr.2025.12
Reports

Review Open Access

Bile salt hydrolase: a key player in gut microbiota
and its implications for metabolic dysfunction-

associated steatotic liver disease

3
1,#
Weixing Zhao 1,2,# , Huiying Wang , Minghua Zheng , Yan Ni 1,2
1
Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou
310052, Zhejiang, China.
2
Department of Epidemiology and Biostatistics, School of Public Health, Zhejiang University, Hangzhou 310058, Zhejiang, China.
3
MAFLD Research Center, Department of Hepatology, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou
325000, Zhejiang, China.
#
Authors contributed equally.
Correspondence to: Prof. Yan Ni, Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center
for Child Health, 3333 Binsheng Road, Hangzhou 310052, Zhejiang, China. E-mail: yanni617@zju.edu.cn
How to cite this article: Zhao W, Wang H, Zheng M, Ni Y. Bile salt hydrolase: a key player in gut microbiota and its implications
for metabolic dysfunction-associated steatotic liver disease. Microbiome Res Rep. 2025;4:28. https://dx.doi.org/10.20517/mrr.
2025.12
Received: 5 Mar 2025 First Decision: 23 Jun 2025 Revised: 12 Jul 2025 Accepted: 28 Jul 2025 Published: 30 Jul 2025

Academic Editors: Marco Ventura, Jie Yin Copy Editor: Ping Zhang Production Editor: Ping Zhang

Abstract
The rising prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) poses a significant
global public health challenge. Bile acids (BAs), synthesized in the liver and further metabolized in the gut, are
essential in maintaining host metabolic homeostasis. Bile salt hydrolase (BSH), an enzyme produced by the gut
microbiota, catalyzes the hydrolysis of conjugated BAs, thus regulating the balance between primary and
secondary BAs. Growing evidence suggests that BSH activity is intricately linked to the pathogenesis of MASLD.
This review comprehensively examines the structural and functional properties of BSH enzymes, their distribution
among gut microbial communities, and current methodologies for assessing BSH expression and activity.
Furthermore, it highlights the alterations in BSH observed in MASLD and explores the potential mechanistic
pathways involved, offering a foundation for the development of novel diagnostic and therapeutic strategies.

Keywords: Bile salt hydrolase, gut microbiota, bile acids, metabolic dysfunction-associated steatotic liver disease

© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0
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