nasal-brushing-sampling-processing-using-digital-high-speed-ciliary

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

Primary Ciliary Dyskinesia (PCD) is a genetic motile ciliopathy, leading to significant otosinopulmonary disease. PCD diagnosis is often missed or delayed ...

University of British Columbia and British Columbia Children's Hospital

This study aimed to determine whether antimicrobial susceptibility testing of Pseudomonas aeruginosa grown as a biofilm, rather than planktonically, improves efficacy of antibiotic treatment for pulmonary exacerbations. This was a multicenter randomized, double-blind controlled trial of 14 days of intravenous antibiotic treatment for pulmonary exacerbations chosen based on conventional vs. biofilm antimicrobial susceptibility results in CF patients with chronic P. aeruginosa infection. There were 74 exacerbations in 39 patients. A total of 46% (12/26) exacerbations in the conventional group compared to 40% (19/48) exacerbations in the biofilm group achieved a ≥3 log drop in P. aeruginosa sputum density (difference -0.03, 95% CI -0.5 to 0.4, p=0.9). Lung function improvements were similar in both groups. Biofilm antimicrobial susceptibility testing did not lead to improved microbiological or clinical outcomes compared to conventional methods in the treatment of pulmonary exacerbations in CF patients with chronic P. aeruginosa.

Randomized controlled trial of biofilm antimicrobial susceptibility testing in cystic fibrosis patients.

Pulmonary exacerbations are associated with significant lung function decline from baseline in cystic fibrosis (CF) and it is not well understood why some patients do not respond to antibiotic therapy. The objective of this study was to identify factors associated with lung function response to antibiotic treatment of pulmonary exacerbations.

Factors associated with response to treatment of pulmonary exacerbations in cystic fibrosis patients.

Digital high-speed video microscopy (DHSV) allows analysis of ciliary beat frequency (CBF) and ciliary beat pattern (CBP) of respiratory cilia in three planes. Normal reference data use a sideways edge to evaluate ciliary dyskinesia and calculate CBF using the time needed for a cilium to complete 10 beat cycles. Variability in CBF within the respiratory epithelium has been described, but data concerning variation of CBP is limited in healthy epithelium. This study aimed to document variability of CBP in normal samples, to compare ciliary function in three profiles, and to compare CBF calculated over five or 10 beat cycles.

Variation of Ciliary Beat Pattern in Three Different Beating Planes in Healthy Subjects.

Response.

Cilia are widely distributed throughout the human body, and have numerous roles in physiology, development, and disease. Ciliary ultrastructure is complex, consisting of nine parallel microtubules doublets, with or without motor dynein arms and a central pair of microtubules. Classification of cilia has evolved over time, and currently, four main classes are described: motile and non-motile cilia with a "9 + 2" structure, and motile and non-motile cilia with a "9 + 0" structure, which depend on the presence or absence of dynein arms and a central pair. Ciliopathies are inherited multisystem disorders of cilia, and may present with a varied spectrum of genotypes and phenotypes. Motor and sensory ciliopathies were historically considered as distinct dysfunctions of motile and non-motile cilia, but recent data indicate that the classical features of motor and sensory cilia may overlap.

To beat, or not to beat, that is question! The spectrum of ciliopathies.

KIWI (NCT01705145) was a 24-week, single-arm, pharmacokinetics, safety, and efficacy study of ivacaftor in children aged 2 to 5 years with cystic fibrosis (CF) and a CFTR gating mutation. Here, we report the results of KLIMB (NCT01946412), an 84-week, open-label extension of KIWI.

An open-label extension study of ivacaftor in children with CF and a CFTR gating mutation initiating treatment at age 2-5 years (KLIMB).

Tezacaftor/ivacaftor is a new treatment option in many regions for patients aged ≥12 years who are homozygous (F/F) or heterozygous for the F508del-CFTR mutation and a residual function (F/RF) mutation. This Phase 3, 2-part, open-label study evaluated the pharmacokinetics (PK), safety, tolerability, and efficacy of tezacaftor/ivacaftor in children aged 6 through 11 years with these mutations.

A phase 3 study of tezacaftor in combination with ivacaftor in children aged 6 through 11 years with cystic fibrosis.

Primary ciliary dyskinesia is an inherited disorder in which respiratory cilia are stationary, or beat in a slow or dyskinetic manner, leading to impaired mucociliary clearance and significant sinopulmonary disease. One diagnostic test is ciliary functional analysis using digital high-speed video microscopy (DHSV), which allows real-time analysis of complete ciliary function, comprising ciliary beat frequency (CBF) and ciliary beat pattern (CBP). However, DHSV lacks standardization. In this paper, the current knowledge of DHSV ciliary functional analysis is presented, and recommendations given for a standardized protocol for ciliary sample collection and processing. A proposal is presented for a quantitative and qualitative CBP evaluation system, to be used to develop international consensus agreement, and future DHSV research areas are identified.

Ciliary functional analysis: Beating a path towards standardization.

Newborn screening for Cystic Fibrosis has been implemented in most programs worldwide, but the approach used varies, including combinations of immunoreactive trypsinogen (IRT) and CFTR mutation analysis on one or more specimens. The British Columbia (BC) newborn screening program tests ~45,000 infants per year in BC and the Yukon Territory, covering almost 1.5 million km in western Canada. CF screening was initiated using an IRT-DNA-IRT approach with a second bloodspot card at 21 days of age for all CFTR mutation heterozygotes and any non-carriers in the top 0.1% for IRT. This second IRT was implemented to avoid sweat testing of infants without persistent hypertrypsinemia, reducing the burden of travel for families. Over nine years (2010-2018), 401,977 infants were screened and CF was confirmed in 76, and a further 28 were deemed CF screen positive inconclusive diagnosis (CFSPID). Day 21 IRT was normal in 880 CFTR mutation carriers who were quoted a very low CF risk and offered optional sweat testing. Only 13% of families opted for sweat testing and a total of 1036 sweat tests were avoided. There were six false negative CF cases (and three CFSPID) due to a low initial IRT or no CFTR mutations. Although one CFSPID case had a normal repeat IRT result, the addition of the day 21 IRT did not contribute to any CF false negatives.

Article	Year
Randomized controlled trial of biofilm antimicrobial susceptibility testing in cystic fibrosis patients. Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society\| PubMed ID: 25453872	2015
Factors associated with response to treatment of pulmonary exacerbations in cystic fibrosis patients. Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society\| PubMed ID: 25690407	2015
Variation of Ciliary Beat Pattern in Three Different Beating Planes in Healthy Subjects. Chest\| PubMed ID: 27693596	2017
Response. Chest\| PubMed ID: 29223262	2017
To beat, or not to beat, that is question! The spectrum of ciliopathies. Pediatric pulmonology\| PubMed ID: 29938933	2018
An open-label extension study of ivacaftor in children with CF and a CFTR gating mutation initiating treatment at age 2-5 years (KLIMB). Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society\| PubMed ID: 31053538	2019
A phase 3 study of tezacaftor in combination with ivacaftor in children aged 6 through 11 years with cystic fibrosis. Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society\| PubMed ID: 31253540	2019
Ciliary functional analysis: Beating a path towards standardization. Pediatric pulmonology\| PubMed ID: 31313529	2019
Performance of a Three-Tier (IRT-DNA-IRT) Cystic Fibrosis Screening Algorithm in British Columbia. International journal of neonatal screening\| PubMed ID: 33073036	2020

Mark A. Chilvers

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