H pylori colocalises with MUC5AC in the human stomach

Abstract

BACKGROUND The bacterium Helicobacter pyloriis able to adhere to and to colonise the human gastric epithelium, yet the primary gene product responsible as a receptor for its adherence has not been identified. AIMS To investigate the expression of the gastric mucins MUC5AC and MUC6 in the gastric epithelium in relation to H pyloricolonisation in order to examine their possible roles in the binding of H pylori. PATIENTS Seventy two consecutive patients suspected of having H pylori infection. METHODS MUC5AC, MUC6, and H pylori were detected in single sections of antral biopsy specimens using immunohistochemical triple staining. RESULTS MUC5AC was expressed in the superficial epithelium and the upper part of the gastric pits. MUC6 expression was detected in the lower part of the gastric pits. The expression of both mucins in the epithelium was complementary. In each patient, there was a sharply delineated transition between MUC5AC and MUC6 producing cell populations. In allH pylori positive patients there was a striking colocalisation of H pylori and MUC5AC; more than 99% of the bacteria were associated with either extracellular MUC5AC or the apical domain of MUC5AC producing cells. CONCLUSIONS H pylori is very closely associated with extracellular MUC5AC and epithelial cells that produce MUC5AC. This indicates that MUC5AC, but not MUC6, plays a role in the adhesion ofH pylori to the gastric mucosa.