Summary

Mucin gene 5AC (MUC5AC), a secreted mucin, is the most important component of the gastric mucus unstirred, protecting layer, preventing the enzymatic attack of acid and pepsin, toxins, and microorganisms. We investigated the effect of Helicobacter pylori (H. pylori) infection on MUC5AC expression in the gastric mucosa. English language medical literature searches were conducted for gastric MUC5AC expression in H. pylori infected patients compared to uninfected people, or cases after eradication. PubMed, EMBASE, Scopus, and CENTRAL databases were searched. Meta-analysis was performed and pooled odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated. Heterogeneity was evaluated and I² statistic was used to measure the proportion of inconsistency in individual studies.

We also calculated a potential publication bias. In all, 11 studies representing 13 sub-studies were selected according to the inclusion criteria. The OR of MUC5AC expression in a random effect analysis was 0.217, 95%CI 0.124–0.377, P < 0.0001, significantly lower in H. pylori gastritis than in normal mucosa. When only studies with high-quality scores were calculated, OR was 0.239, 95%CI 0.137–0.419, P < 0.0001. Heterogeneity and inconsistency were small, with no significant publication bias. MUC5AC expression is lower in H. pylori infected mucosa, which may significantly affect the effective colonization and survival of the bacterium and persistent chronic inflammation.