Nasal polyps and middle turbinates epithelial cells sensitivity to amphotericin B

Intranasal application of the antimycotic agent amphotericin B (AmphoB) has been proposed as an effective treatment of chronic rhinosinusitis (CRS) with polyps. AmphoB is a sterol-binding agent known to modify cell membrane structure. The cytotoxic effects of AmphoB were studied on primary human nasal epithelial cells in vitro.

Human epithelial cells were isolated from nasal polyps and middle turbinates of patients suffering from CRS, and grown on collagen-coated polycarbonate filters with an air liquid-interface. After 15 days of culture, cells were exposed apically to 50 microM AmphoB during 4 h daily for 5 days. Some cells were treated during 4 weeks. The bioelectric properties of cells were then studied in Ussing chambers. Integrity of the cell monolayers was assessed by measurement of the transepithelial resistance (R) and immunofluorescent localization of the tight junction protein occludin.

Disruption of the epithelial monolayer integrity was observed in all of the nasal polyps cell cultures, as demonstrated by a 60% drop in R. Immunofluorescence microscopy showed significant loss in cell number and disruption in the distribution of occludin. Turbinate cell cultures elicited no change in R and expression of occludin after AmphoB treatment. However, the transepithelial potential, the basal short-circuit current and the amiloride-sensitive current were reduced by 70%.

AmphoB was cytotoxic for nasal polyp epithelial cells with disruption of the epithelium integrity and loss of tight junctions. In contrast, integrity of turbinate epithelial cells was conserved despite alterations in transepithelial ion transport. These observations may explain the beneficial effect of intranasal application of AmphoB on CRS observed in clinical trials.