Methods: Nasal mucosa (NM, n=3) and nasal polyps (NP, n=3) were obtained from patients undergoing nasal corrective surgery and endoscopic sinus surgery, respectively. Epithelial cells were obtained from the explant method, and differentiated in ALI culture during 28 days. Cultures were studied at different time points (0, 7, 14, 21, and 28 days): tissue ultrastructure by scanning electron microscopy (SEM) and transmission electron microscopy (TEM); mucous (MUC5AC, MUC5B) and serous (lactoferrin) cell secretion by ELISA; and cytokeratin 18 (epithelial marker), β-tubulin IV (cilia marker), MUC5AC (goblet cell marker), and p63 (basal cell marker) expression by immunocytochemistry.
Results: In both NM and NP ALI cultures and at days 14 and 28, a pseudostratified epithelium with ciliated, mucus-secreting and basal cells was observed, and expression of cytokeratin 18, b-tubulin IV, MUC5AC and p63 was detected. In NP cultures, both MUC5AC (day 14: 2.2±0.1 folds; day 28: 3.6±0.7 folds) and MUC5B (day 14: 3.2±0.6 folds; day 28: 3.1±1 folds) increased over time compared to day 0 (p<0.05). In NM cultures, only MUC5B (day 14: 3.9±0.9 folds; day 28: 3.4±0.4 folds; p<0.05) but not MUC5AC increased over time compared to day 0 (p<0.05). Secretion of lactoferrin was present but showed no changes over time in either NM or NP ALI cultures.
Conclusions: Epithelial cell ALI cultures provide a well-differentiated human nasal mucosa and polyp tissues that may be used as an in vitro model to study mucin regulation, inflammatory mechanisms of upper airways, and their regulation by antiinflammatory drugs.