New analysis of the mechanisms controlling the bronchial mucus balance

Lining the bronchi in the lung, the mucus constitutes a protective layer from harmful pathogens and particles. Its displacement due to the coordinated beating of the bronchial epithelium cilia contributes to its clearance from the lung. As this mucociliary clearance is impaired in numerous pathologies, a comprehensive understanding of this process is critical. A simple mass balance over the mucus layer in an airway suggests that the cilia beating, on its own, is not sufficient enough for controlling the bronchial mucus balance in the entire lung. In this article, we show through a mathematical modeling approach that the evaporation of the water contained in the mucus layer could act as a control mechanism of the mucus balance. Furthermore, we suggest that other control mechanisms act in parallel to evaporation to maintain the mucus balance. Our model and results could be useful in the study and management of several mucus-related airway diseases , such as cystic fibrosis or exercise-induced asthma.