Potential role of abnormal ion transport in the pathogenesis of chronic sinusitis

Objectives: To create well-differentiated cultures of normal and chronic sinusitis paranasal sinus epithelial cells and to compare their electrophysiologic properties. Design: In vitro investigation using primary sinus epithelial cells, initially cultured on plastic tissue culture dishes. Cells were characterized by means of immunocytochemical analysis and then passaged to air-liquid interface culture conditions. The morphologic features of air-liquid interface cultures were assessed using light and electron microscopy. Epithelial Na+ channel, Na+-K+-2Cl-cotransporter, cystic fibrosis transmembrane conductance regulator, and Ca2+-activated Cl- channel function were investigated in Ussing chambers. Subjects: Specimens were obtained from 15 patients undergoing transsphenoidal pituitary procedures, tumor removal, or trauma repair and from 9 patients with chronic sinusitis. Results: After culture at an air-liquid interface for 21 days, the epithelium was pseudostratified and contained basal, mucous secretory, and ciliated cells. There were no detectable morphologic differences between normal and chronic sinusitis cells. In cultures of normal cells, median basal short circuit current was 4.7 mu A/cm(2), and Na+ transport, defined as the amiloride hydrochloride-sensitive component, was approximately 20% of the total. Basal and amiloride-sensitive short circuit currents were greater in cultures of chronic sinusitis cells. Basal short circuit currents in both types of cultures were insensitive to the Cl- transport inhibitor bumetanide, but all responded to forskolin or uridine triphosphate. After amiloride pretreatment, forskolin and uridine triphosphate responses were greater in chronic sinusitis cells. Conclusions: We established methods for well-differentiated sinus epithelial cultures. The cells exhibited Na+ absorption and Cl- secretion, and elevated rates of ion transport may be pathophysiologically relevant in chronic sinusitis.