Assessment of ciliary phenotype in primary ciliary dyskinesia by micro-optical coherence tomography.

Ciliary motion defects cause defective mucociliary transport (MCT) in primary ciliary dyskinesia (PCD). Current diagnostic tests do not assess how MCT is affected by perturbation of ciliary motion. In this study, we sought to use micro-optical coherence tomography (μOCT) to delineate the mechanistic basis of cilia motion defects of PCD genes by functional categorization of cilia motion. Tracheae from three PCD mouse models were analyzed using μOCT to characterize ciliary motion and measure MCT. We developed multiple measures of ciliary activity, integrated these measures, and quantified dyskinesia by the angular range of the cilia effective stroke (ARC). Ccdc39 ^-/- mice, with a known severe PCD mutation of ciliary axonemal organization, had absent motile ciliary regions, resulting in abrogated MCT. In contrast, Dnah5 ^-/- mice, with a missense mutation of the outer dynein arms, had reduced ciliary beat frequency (CBF) but preserved motile area and ciliary stroke, maintaining some MCT. Wdr69 ^-/- PCD mice exhibited normal motile area and CBF and partially delayed MCT due to abnormalities of ciliary ARC. Visualization of ciliary motion using μOCT provides quantitative assessment of ciliary motion and MCT. Comprehensive ciliary motion investigation in situ classifies ciliary motion defects and quantifies their contribution to delayed mucociliary clearance.
Competing Interests: Conflict of interest: The University of Alabama at Birmingham and Massachusetts General Hospital have filed for an unlicensed patent on the use of µOCT toward the functional imaging of respiratory mucosa, including for the use of high-throughput screening, estimation of rheology, and functional anatomy (e.g., cilia beating, airway surface liquid depth, and mucociliary transport) (US patent application 14/240,938). K.K. Chu, G.J. Tearney, and S.M. Rowe are named on the patent application.