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Abstract Objective Mucociliary transport function in the airway mucosa is essential for maintaining a clean mucosal surface. This function is impaired in upper and lower airway diseases. Nasal polyps are a noticeable pathological feature that develop in some of the patients with chronic rhinosinusitis. Like ordinary nasal mucosae, nasal polyps have a ciliated pseudostratified epithelium with vigorous ciliary beating. We measured ex vivo Mucociliary Transport Velocity (MCTV) and Ciliary Beat Frequency (CBF) and explored the expressions of Planar Cell Polarity (PCP) proteins in nasal polyps in comparison with turbinate mucosae. Methods Inferior turbinates and nasal polyps were surgically collected from patients with chronic rhinosinusitis. Ex vivo MCTV and CBF were measured using a high-speed digital imaging system. Expressions of PCP proteins were explored by fluorescence immunohistochemistry and quantitative RT-PCR. Results The MCTV of nasal polyps was significantly lower than that of the turbinates (7.43 ± 2.01 vs. 14.56 ± 2.09 μm/s; p= 0.0361), whereas CBF did not differ between the two tissues. The MCTV vector was pointed to the posteroinferior direction in all turbinates with an average inclination angle of 41.0 degrees. Immunohistochemical expressions of Dishevelled-1, Dishevelled-3, Frizzled3, Frizzled6, Prickle2 and Vangl2 were lower in the nasal polyps than in the turbinates. Confocal laser scanning microscopy showed that Frizzled3 was localized along the cell junction on the apical surface. The expression levels of mRNAs for Dishevelled-1, Dishevelled-3 and Frizzled3 in the nasal polyps were also decreased in comparison with the turbinates. Conclusion These results indicate that muco ciliary transport in nasal polyps is impaired although vigorous ciliary beating is maintained, and that the impairment may be caused by a decrease in Dishevelled/Frizzled proteins and resultant PCP disarrangement. Level of evidence: Level 3.
RESUMO
BACKGROUNDS AND OBJECTIVES: Mucus hypersecretion is a common feature in chronic sinusitis with polyps. Since mucus hypersecretion is commonly accompanied by goblet cell hyperplasia, it is important to identify which mucin gene mRNAs are expressed in the goblet cells of the surface epithelium in the human airway. This study aims to investigate the pattern of expression of MUC5AC mRNA in the goblet cells of human nasal mucosa. MATERIALS AND METHODS: Six nasal polyps, five inferior turbinate mucosa specimens, and three normal-appearing mucosa specimens of the posterior ethmoid sinus were obtained. Each of the specimens were cut into 10 micromiter thick serial frozen sections and in situ hybridization of MUC5AC mRNA was performed with an oligonucleotide probe. Alcian blue(pH 2.5)-periodic acid-Schiff staining was performed on the serial sections. RESULTS: In human nasal polyps, MUC5AC mRNA was expressed in the cytoplasm of most of the goblet cells. However, in the inferior turbinate, MUC5AC mRNA was expressed in only some of the goblet cells. On the contrary, in the normal appearing mucosa of the posterior ethmoid sinus, MUC5AC mRNA was barely expressed in the goblet cells. Furthermore, MUC5AC mRNA was mainly expressed in some of the PAS-positive goblet cells. CONCLUSION: Only a portion of the goblet cells in the human nasal mucosa expressed MUC5AC mRNA. This result suggests that surface goblet cells might have other mucin genes in addition to MUC2 and MUC5AC.