The abundance of Akkermansia muciniphila and its relationship with sulphated colonic mucins in health and ulcerative colitis

Akkermansia muciniphila utilises colonic mucin as its substrate. Abundance is reduced in ulcerative colitis (UC), as is the relative proportion of sulphated mucin in the mucus gel layer (MGL). It is unknown if these phenomena are related, however reduced sulphated mucins could contribute to reduced abundance, owing to a lack of substrate. The aim of this study was to quantify A. muciniphila within the MGL and to relate these findings with markers of inflammation and the relative proportion of sulphomucin present. Colonic biopsies and mucus brushings were obtained from 20 patients with active UC (AC), 14 with quiescent UC (QUC) and 20 healthy controls (HC). A. muciniphila abundance was determined by RT-PCR. High iron diamine alcian-blue staining was performed for histological analysis. Patients with AC had reduced abundance of A. muciniphila compared to HC and QUC. A positive association was found between A. muciniphila abundance and higher percentage of sulphated mucin (ρ 0.546, p = 0.000). Lower abundances of A. muciniphila correlated with higher inflammatory scores (ρ = 0.294 (p = 0.001)). This study confirms an inverse relationship between A. muciniphila and inflammation and a positive association between A. muciniphila abundance and percentage of sulfated mucin in the MGL.