Impairment of Nasal Epithelial Barrier Function in Nasal Polyps

Epithelial barrier dysfunction and sinonasal mucosal inflammation caused by multiple risk factors such as infection, genetic, environment, and immunity are commonly reported in chronic rhinosinusitis (CRS) with and without nasal polyps (NP). In particularly, hyperplasia of basal cells and goblet cells, impairment of cilia architecture together with abnormal expression levels of ciliogenesis-associated proteins in ciliated columnar cells are commonly shown in epithelium of NPs. These findings are also confirmed by in vitro data with reduced growth and proliferation activities in human nasal epithelial stem/progenitor cells (hNESPCs), increased mucus production, and abnormal cilia architecture in differentiated nasal epithelial cells derived from hNESPCs, suggesting that these pathophysiological changes are likely underlying intricate immune-pathophysiological processes. This chapter reviews mainly our own research findings in histopathological and pathogenic alterations in nasal epithelium of NPs together with the literature data.