Effects of Bacterial Toxins on Air-Exposed Cultured Human Respiratory Sinus Epithelium

The present study was designed to investigate the effects of the bacterial toxins lipopolysaccharide (LPS) and lipoteichoic acid (LTA) on air-exposed cultured human respiratory sinus epithelium. The morphological changes, proliferation, and differentiation of sphenoid sinus mucosa were examined after incubation with different LPS or LTA concentrations. Air-exposed cultured sinus mucosa differentiated from pseudostratified respiratory epithelium to squamous ciliated epithelium with few goblet cells. High concentrations of bacterial toxins induced a significant increase in mucus production and a decrease in ciliated cells. Ki67 immunostaining showed an increased cell proliferation after incubation with moderate levels of LPS or LTA. High concentrations of bacterial toxins, on the other hand, induced a decreased proliferation. Involucrin expression was clearly altered by incubation with high levels of bacterial toxins, indicating an increased degree of terminal differentiation. These results indicate that the bacterial toxins LPS and LTA both induce comparable dose-dependent morphological changes in sinus epithelium.