Mucin Genes Expression in the Intestine of Crohn's Disease Patients: a Systematic Review and Meta-analysis

Background & Aims: The mucus layer of the intestinal tract is the main barrier between luminal microbes and the mucosa, and has an essential role in the body defense mechanisms. Previous research could not establish consistent results for mucin genes expression in Crohn's disease (CD) patients. In this meta-analysis we looked at the mucin expression in CD patients and compared it with healthy controls. Method. English medical literature searches were conducted for mucin expression in the mucosa of the ileum and colon of CD patients and compared it with normal mucosa. Case control studies were included. Meta-analysis was performed by using Comprehensive meta-anaslysis software. Pooled odds ratios and 95% confidence intervals were calculated. Results. We found 160 eligible studies. Twenty studies were rejected because they have been performed in animals or did not have full text, and 134 studies were excluded because of language, being editorials, review articles, or because of duplications. We were left with 6 case-control studies from 4 countries that fulfilled the inclusion criteria, published till 31.12.2015. No significant heterogeneity was demonstrated: Q = 149.256, df (Q) = 40.00, I-2= 73.2% (less than 75%). We found a decrease of 34% in the total mucin expression in CD patients (Odds Ratio 0.660, 95% CI 0.486-0.897, P = 0.008). We also found a significantly decreased expression in CD patients for MUC5AC, MUC5B and MUC7. Conclusion. We demonstrated a global decrease in mucin expression in CD patients when compared with healthy controls.