Increased small intestinal permeability and RNA expression profiles of mucosa from terminal ileum in patients with diarrhoea-predominant irritable bowel syndrome.

BACKGROUND

Altered intestinal permeability in diarrhoea-predominant irritable bowel syndrome (IBS-D) has been reported in some studies.

AIMS: The study aimed to investigate the altered intestinal permeability and its associated clinical characteristics and RNA expression profiles in IBS-D.

METHODS

We stratified IBS-D patients into two groups according to the P95 value of the permeability in controls. The clinical characteristics of the two groups were evaluated, and two biopsy cases from each of the two groups were selected for the RNA-seq analysis.

RESULTS

IBS-D patients had a significant increase in the small intestinal permeability compared with controls [0.0245 (0.0229) median (interquartile range)] versus 0.0156 (0.0098), P=0.010), but no significant difference was found in the colonic permeability [23.286 (10.470) versus 21.650 (6.650), P=0.574]. The IBS-D patients with increased small intestinal permeability had worse psychological effects (P=0.027) and quality of life (P=0.044). Analysis of RNA-seq data revealed 185 genes differentially expressed, many of which were related to mucosal inflammation and immunity.

CONCLUSIONS

Small intestinal permeability, but not colonic permeability, is increased in IBS-D patients. IBS-D patients with increased small intestinal permeability tend to be more severely impaired in terms of psychological effects and quality of life, and analysis of RNA-seq data reveals that increased small intestinal permeability is related to mucosal inflammation and immunity.