Nasal Brushing Sampling and Processing Using Digital High Speed Ciliary Videomicroscopy – Adaptation for the COVID-19 Pandemic

Summary

To guarantee a successful and high-quality ciliary functional analysis for PCD diagnosis, a precise and careful method for respiratory epithelium sampling and processing is essential. To continue providing PCD diagnostic service during the COVID-19 pandemic, the ciliary videomicroscopy protocol has been updated to include appropriate infection control measures.

Abstract

Primary Ciliary Dyskinesia (PCD) is a genetic motile ciliopathy, leading to significant otosinopulmonary disease. PCD diagnosis is often missed or delayed due to challenges with different diagnostic modalities. Ciliary videomicroscopy, using Digital High-Speed Videomicroscopy (DHSV), one of the diagnostic tools for PCD, is considered the optimal method to perform ciliary functional analysis (CFA), comprising of ciliary beat frequency (CBF) and beat pattern (CBP) analysis. However, DHSV lacks standardized, published operating procedure for processing and analyzing samples. It also uses living respiratory epithelium, a significant infection control issue during the COVID-19 pandemic. To continue providing a diagnostic service during this health crisis, the ciliary videomicroscopy protocol has been adapted to include adequate infection control measures.

Here, we describe a revised protocol for sampling and laboratory processing of ciliated respiratory samples, highlighting adaptations made to comply with COVID-19 infection control measures. Representative results of CFA from nasal brushing samples obtained from 16 healthy subjects, processed and analyzed according to this protocol, are described. We also illustrate the importance of obtaining and processing optimal quality epithelial ciliated strips, as samples not meeting quality selection criteria do now allow for CFA, potentially decreasing the diagnostic reliability and the efficiency of this technique.

Introduction

Primary ciliary dyskinesia (PCD) is an inherited heterogeneous motile ciliopathy, in which respiratory cilia are stationary, slow or dyskinetic, leading to impaired mucociliary clearance and chronic oto-sino-pulmonary disease^1,2,3,4. The clinical manifestations of PCD are chronic wet cough and chronic nasal congestion starting in early infancy, recurrent or chronic upper and lower respiratory tract infections leading to bronchiectasis, and recurrent or chronic otitis media and sinusitis^5,6....

Protocol

Approval was obtained from the Liege hospital-faculty ethics committee and the University Department for Hygiene and Health Protection at Work.

1. Sampling respiratory ciliated epithelium

1. Ensure that subjects are free of infection for at least 4-6 weeks, and free of nasal and inhaled medication, before sampling.
2. Prepare supplemented M199 preparation: Supplement Cell Culture Medium 199 (M199) (500 mL) with antibiotic solution (5 mL of streptomycin/penicillin (50 μg/mL.......

Discussion

This paper aims to provide a standard operating procedure for CFA using nasal brushing samples, with adjustments made for appropriate infection control considerations during the COVID-19 pandemic. PCD diagnosis is challenging, and currently requires a panel of different diagnostic tests, according to international recommendation, including nasal nitric oxide measurement, CFA using DHSV, ciliary ultrastructural analysis using transmission electron microscopy (TEM), labelling of ciliary proteins using immunofluorescence, a.......

Materials

Name	Company	Catalog Number	Comments
15 mL conical tubes	FisherScientific	352096	15 ml High-Clarity Polypropylene Conical Tube with lid
Amphotericin B	LONZA	17-836E	Antifungal solution
Blakesley-weil nasal forceps	NOVO SURGICAL	E7739-12	Used to hold the brush to perform the nasal brushing
Bronchial cytology brush	CONMED	129	Used for nasal brushing
Cotton swab	NUOVA APTACA	2150/SG	Used for COVID-19 testing
Digitial high-speed videomicroscopy camera	IDTeu Innovation in motion	CrashCam Mini 1510
Glass slide	ThermoScientific	12372098	Microscope slides used to create the visualization chamber
Heated Box	IBIDI cells in focus	10918	Used to heat the sample
Inverted Light microscope	Zeiss	AXIO Vert.A1
Lens Heater	TOKAI HIT	TPiE-LH	Used to heat the oil immersion lens
Medium 199 (M199), HEPES	TermoFisher Scientific	12340030	Cell Culture Medium
Motion Studio X64	IDT Motion	version 2.14.01	Software
Oil	FischerScientific, Carl Zeiss	11825153
Rectangular cover slip	VWR	631-0145	Used to cover the visualization chamber
Spacer (Ispacer) 0.25 mm	Sunjinlab	IS203	Used for the creation of the hermetic closed visualization chamber
Square cover slip	VWR	631-0122	Used for the creation of lab-built open visualization chamber
Streptomycin/Penicillin	FisherScientific, Gibco	11548876	Antiobiotics solution