Inherent differences in nasal and tracheal ciliary function in response to Pseudomonas aeruginosa challenge

Sinonasal mucosal biofilms are recognized as contributors to the pathogenesis of chronic rhinosinusitis (CRS). Attachment of bacteria to the sinonasal surface is an initial step in biofilm formation. A critical defense against this occurrence is mucociliary clearance (MCC). To ascertain whether the ciliary component of MCC is uniform throughout the airway we compared ciliary beat frequency (CBF) in the murine nasal septum and trachea at baseline and after challenge with Pseudomonas aeruginosa, a common pathogen of CRS.

Murine septal and tracheal air-liquid interface cultures were evaluated for basal and stimulated CBF after exposure to control or conditioned media from Pseudomonas. Additionally, the attachment of Pseudomonas to nasal and tracheal cultures was assessed after pretreatment with control or conditioned media.

Basal CBF is significantly slower in primary nasal airway cultures compared with tracheal airway cultures. Tracheal airway cultures show resistance to Pseudomonas secreted ciliotoxins not evident in nasal septal cultures. Furthermore, after challenge with viable Pseudomonas, significantly more bacteria attach to the nasal cultures compared with the tracheal cultures.

Using primary murine nasal and tracheal airway cultures we show inherent differences in cilia function and increased susceptibility of the upper airway to attachment by Pseudomonas. Understanding the differences between upper and subglottic airway mucociliary clearance should lead to novel approaches in the management of upper airway infection.