Mucociliary clearance – a critical upper airway host defense mechanism and methods of assessment

Abstract

Mucociliary clearance is a critical host defense mechanism of the airways. Effective mucociliary clearance requires appropriate mucus production and coordinated ciliary activity. The important role of these two components is best demonstrated in disorders such as primary ciliary dyskinesia and cystic fibrosis, both of which lead to lifelong recurrent respiratory tract infections. We review the methods used to analyze mucociliary clearance. Utilization of microdialysis probes has improved temporal resolution of mucociliary clearance in murine airways, availing many genetic mouse models to critical mucociliary clearance analysis, while improved fixation technique for transmission electron microscopy has allowed for detailed resolution of the airway surface liquid. High-speed digital video analysis has improved quantification of ciliary beat frequency while advancements in air-liquid interface culturing techniques have generated in-vitro models to investigate mucociliary clearance. Advancements in techniques for analysis of mucociliary clearance have improved our understanding of the interaction between the respiratory epithelium and the airway surface liquid, resulting in the ability to study pathologic processes involving mucociliary clearance in great detail.