A MECHANICAL EVALUATION OF THE CILIARY BEATING EFFICIENCY
PRESENTING AUTHORS FULL NAME: Bruno Louis
INSTITUTION: INSERM U955 – CNRS ERL 7000 – UPEC Faculté de médecine Créteil, France
ADDITIONAL AUTHORS NAMES, AS TO BE PUBLISHED: Marion Renaud, Mathieu Bottier, Sylvain Blanchon, Emilie Bequignon, Daniel Isabey, André Coste, Estelle Escudier, Jean-François Papon, James B. Grotberg, Marcel Filoche
BACKGROUND/PURPOSE: Mucociliary clearance is one of the major lines of defense of the respiratory system. Goblet cells produce mucus trapping the aerocontaminants. The mucus layer is carried along the airway tree towards the pharynx where it is swallowed. This transport relies on the constant ciliary beating of the respiratory epithelium. Ciliary beating is a complex motion resulting from the asymmetrical beating pattern of each individual cilium that combinates with all the adjacent cilia forming the so-called metachronal wave. Diseases relating to dysfunction of motile cilia can include rare inherited diseases like primary ciliary dyskinesia but also much more common diseases such as rhinosinusitis, otitis, asthma or chronic obstructive pulmonary disease. An understanding of the characteristics of ciliary beating may inform treatment and diagnostic decisions, but reliable methods for evaluating the efficiency of ciliary beating on the mucociliary transport are lacking.
METHOD: To assess cilary beating efficiency, we developed an ex vivo experimental microbead tracking method in order to evaluate the steady contribution of the wall shear stress due to the ciliary beating. Backed by a mathematical model, this measurement of the shear stress provides a direct estimate of the force applied by the ciliated epithelium on the surrounding fluid. As such, it appears as a global index of the potential ciliary beat efficiency. By comparing a chronic rhinosinusitis group and a control group, we evaluated the clinical relevance of wall shear stress measurement and compared this new parameter with the results of the classical high-speed videomicroscopy analysis of ciliary beating.
RESULTS: The wall shear stress is significantly lowered in the rhinosinusitis group whereas the frequency is not modified. Measuring the shear stress allows us to distinguish between the 2 groups with a sensitivity of 93% and a specificity of 89% (cut-off of 0.34mPa.)
CONCLUSION: The wall shear stress appears as a new promising parameter to evaluate the ciliary beating efficiency in pathologies affecting ciliary motion and mucociliary clearance. Further study are needed to precise the contribution of this parameter when considering severity of these diseases and ongoing therapeutic interventions.