Probiotics fortify intestinal barrier function: a systematic review and meta-analysis of randomized trials

DOI: https://doi.org/10.3389/fimmu.2023.1143548

Yanfei Zheng^1 2, Zengliang Zhang³, Ping Tang^1 2, Yuqi Wu^1 2, Anqi Zhang², Delong Li^1 2, Chong-Zhi Wang^4 5, Jin-Yi Wan^1 2, Haiqiang Yao^1 2, Chun-Su Yuan^4 5

¹School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China; ²National Institute of Traditional Chinese Medicine (TCM) Constitution and Preventive Medicine, Beijing University of Chinese Medicine, Beijing, China; ³Traditional Chinese Medicine College, Inner Mongolia Medical University, Inner Mongolia, China; ⁴Tang Center for Herbal Medicine Research, The University of Chicago, Chicago, IL, United States; ⁵Department of Anesthesia and Critical Care, The University of Chicago, Chicago, IL, United States

Abstract

Background: Probiotics play a vital role in treating immune and inflammatory diseases by improving intestinal barrier function; however, a comprehensive evaluation is missing. The present study aimed to explore the impact of probiotics on the intestinal barrier and related immune function, inflammation, and microbiota composition. A systematic review and meta-analyses were conducted.

Methods: Four major databases (PubMed, Science Citation Index Expanded, CENTRAL, and Embase) were thoroughly searched. Weighted mean differences were calculated for continuous outcomes with corresponding 95% confidence intervals (CIs), heterogeneity among studies was evaluated utilizing I2 statistic (Chi-Square test), and data were pooled using random effects meta-analyses.

Results: Meta-analysis of data from a total of 26 RCTs (n = 1891) indicated that probiotics significantly improved gut barrier function measured by levels of TER (MD, 5.27, 95% CI, 3.82 to 6.72, P < 0.00001), serum zonulin (SMD, -1.58, 95% CI, -2.49 to -0.66, P = 0.0007), endotoxin (SMD, -3.20, 95% CI, -5.41 to -0.98, P = 0.005), and LPS (SMD, -0.47, 95% CI, -0.85 to -0.09, P = 0.02). Furthermore, probiotic groups demonstrated better efficacy over control groups in reducing inflammatory factors, including CRP, TNF-α, and IL-6. Probiotics can also modulate the gut microbiota structure by boosting the enrichment of Bifidobacterium and Lactobacillus.

Conclusion: The present work revealed that probiotics could improve intestinal barrier function, and alleviate inflammation and microbial dysbiosis. Further high-quality RCTs are warranted to achieve a more definitive conclusion.

Clinical trial registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=281822, identifier CRD42021281822.

Keywords: immune function; inflammation; intestinal barrier function; probiotics; randomized controlled trial.