Researchers at the University of Cambridge, in partnership with the University of Strathclyde, have found that cilia—small hair-like structures that line the human airways—not only facilitate the lateral movement of mucus but also create vertical fluid motion that may assist in preventing lung infections.
The study, which appeared in the Proceedings of the National Academy of Sciences (PNAS), was spearheaded by Dr. Erika Causa and her team within Professor Pietro Cicuta’s group at Cambridge, with mathematical modeling contributions from Dr. Debasish Das at the University of Strathclyde. The findings indicate that ciliary activity generates both horizontal and vertical fluid flows, establishing what the authors refer to as a “dynamic barrier” that could hinder bacteria, viruses, and harmful particles from reaching the airway lining cells.
Dr. Das, affiliated with the Department of Mathematics and Statistics at the University of Strathclyde, remarked, “Our research indicates that cilia do more than just transport mucus along the airways; they also propel fluid upwards, away from the lung lining. The synchronized beating of cilia not only supports respiratory health by clearing mucus but also creates a dynamic barrier against the entry of pathogens. This novel insight may pave the way for improved treatments for lung diseases where ciliary function is compromised.”
This research builds upon the well-established knowledge that cilia beat in a coordinated fashion to move mucus and trapped particles toward the mouth. However, through real-time imaging of fluid dynamics within cultured human airway epithelia, the Cambridge team discovered that this coordinated beating also generates upward vertical flow, a phenomenon that had not been documented before.
To monitor this vertical movement, the researchers utilized a technique to ‘uncage’ fluorescent markers within human airway samples. This enabled them to visualize both the rapid horizontal and the slower vertical flows resulting from ciliary activity.
To support the experimental findings, Dr. Das created computational simulations based on slender-body theory.
