Increased mucus concentration reduces airflow-mediated clearance in an in vitro model of cough clearance
Undergraduates: Ayushi Deshwal, Sidd Shenoy, Brian Button
Faculty Advisor: Brian Button
Department: Exercise & Sport Science
Cough clearance is widely known for its significance in diagnosing breathing ailments, in helping to clear blocked airways and in maintaining health. In patients with Cystic Fibrosis, the high velocity and shear forces associated with cough may help to break away mucus from the lumen, and clear pathologic, concentrated and highly viscoelastic mucus. To better understand why cough-clearance fails in CF, we developed an in vitro ¿¿¿cough machine¿¿¿ which incorporates human bronchial epithelial cell cultures with endogenous mucus over a range of mucus concentrations to study effects of air flow rates in the cough regime.
In this study, we investigated mucus clearance rates by airflow that simulated cough. The cough clearance of mucus was captured by observing particles that were stuck to mucus and by using a hi-speed camera during airflow pulses that lasted for a fraction of a second, which emulates a cough event. The results helped correlate complex relationships between various mucus properties such as mucus concentration, oncotic pressure, and rheological properties.
Overall, we found that this in vitro cough clearance model elucidated cough clearance as a relationship with mucus solids concentration, which in turn predicted mucus oncotic pressure and rheological properties. We anticipate that drug therapeutics that modify viscoelastic properties may improve cough clearance rates for both mild and severe CF-like mucus concentrations.