Miki Abo

Nasal nitric oxide (nNO) is an effective screening indicator for primary ciliary dyskinesia (PCD) and a potential biomarker for nasal diseases; however, Measurement of nNO using standard methods is not available everywhere. Therefore, we aimed to estimate nNO values from measured fractional exhaled NO (FeNO) and nasal FeNO (nFeNO) levels using a widely used FeNO analyzer. In this single-center cross-sectional study, the proportion of NO from the lower airway mixed with nFeNO was calculated by simultaneously measuring nFeNO and nNO in 15 healthy participants. Additionally, nNO values were estimated from the measured FeNO and nFeNO in healthy controls and patients with asthma or PCD. The average rate of mixed NO from the lower airway tract was 0.86±0.04. Assuming NO to be 0.86, nNO estimated from the measured FeNO and nFeNO was 329.1±127.8 and 313.4±203.7 parts per billion (ppb) in healthy participants (n=53) and patients with asthma (n=19), respectively. Among patients with asthma, no significant difference was observed in the estimated nNO values between patients with and without peripheral blood eosinophilia; however, the nNO-FeNO ratio was significantly lower in those with eosinophilia. The estimated nNO value in four of eight patients with PCD was <77 nL/min and was used as a cutoff used to identify patients with PCD. The estimated nNO value, which is derived from the average rate of NO contamination from the lower respiratory tract, may be a possible substitute for nNO and can be measured with instruments that are widely used.

Background: A long deletion in the DRC1 gene is one of the common genetic variants observed in primary ciliary dyskinesia (PCD) in Japan. Approximately 49% of PCD cases in Japan are reported to have DRC1 long deletions (Takeuchi K, et al. Mol Genet Genomic Med. 2020;8(3):e1137.) Objective: We analysed the ciliary movements of cultured respiratory epithelial cells obtained from patients with PCD who had DRC1-long deletions. Methods: Respiratory epithelial cells were obtained using a cytology brush from the nasal or bronchial walls of four patients with PCD and several controls without PCD. Written informed consent was obtained from all study subjects before sample collection, and the study was approved by our institution’s ethics committee. Following air-liquid interface culturing, the ciliary movements of the cells were observed using high-speed video analysis. Result: The average ciliary stroke angle was 40.9 ± 13.2° in patients with DRC1 long deletions, and 91 ± 17.5° in the controls. The ciliary beat frequency (CBF) ranged between 4.8 and 31.8 Hz, with an average of 16.3 ± 10.8 Hz in patient 1 and 16.9 ± 9.6 Hz in patient 2 (both with DRC1 long deletions). In a control patient without PCD, CBF ranged between 10.3 and 14.1 Hz, with an average of 12.5 ± 1.2 Hz. Conclusion: Ciliary movement was less flexible and had a smaller amplitude, with a greater degree of CBF variation, in patients with DRC1 long deletions. We believe that this may reduce mucociliary transport. Understanding ciliary movement in cases of PCD with DRC1 long deletions may deepen the general understanding of this disease and aid in the development of new treatment approaches.

In this study, we analyze mucociliary transport (MCT) by measuring the magnitude and identifying regions of ciliary beats using high-frame-rate microscopic videos. Our methodology, integrating dense optical flow (DOF), connected component labeling (CCL), Butterworth filter, and Fast Fourier Transform (FFT), captures ciliary movement and magnitude. We focus on region extraction, quantification of ciliary activity, and classification of power and recovery strokes in ciliary beat frequency (CBF), which are crucial for evaluating MCT efficiency. Our approach was able to extract the ciliary region semi-automatically, obtain the CBF, and visualize the ciliary movement in each frame. Despite dataset challenges and limited ground truth, our approach shows a promising result for ciliary dynamics research and medical diagnostics. We hope for future open-source datasets with ground-truth ciliary beat patterns to enable developing and evaluating automated ciliary analysis techniques, leading to improved assessment.

Turkthoracj, Turkish Thoracic Journal