Ciliary Videomicroscopy: A Long Beat from the European Respiratory Society Guidelines to the Recognition as a Confirmatory Test for Primary Ciliary Dyskinesia

Similar effect of lidocaine and saline on ciliary beating of nasal epithelial cells in vitro

Primary ciliary dyskinesia is a rare genetic disease affecting ciliary motility and causing respiratory symptoms. Diagnosis can be done by high-speed-videomicroscopy using nasal epithelial cells (NECs) obtained via brushings. This procedure can be painful, especially for children. The use of lidocaine is proposed to reduce this pain; however, it is not clear whether lidocaine changes ciliary beating frequency (CBF) or pattern (CBP) in the subsequent high-speed-videomicroscopy. The aim of this study was to analyse the effect of lidocaine on the CBF and the CBP of differentiated, air-liquid-interface cultured NECs.NECs from healthy volunteers were obtained via brushings and cultured at the air-liquid-interface. After differentiation, lidocaine or isotonic saline (IS, control) were added apically for 1 or 5 min each and CBF (in top view of whole inserts and side views of scratched cells) and CBP (only side view) were assessed and recorded up to 150 min. CBF was computed and CBP was analysed semiquantitatively.Lidocaine as well as IS increased the CBF in the top view approach significantly compared to baseline. However, we found no significant differences between lidocaine and IS (control) treatment. Additionally, no effect of lidocaine on CBF, CBP, amplitude, inter- and intracellular coordination or transport was seen in the side view approach.We conclude that the observed CBF increase is related to the addition of liquid on the mucus layer and not by the lidocaine itself. Therefore, it seems possible to use lidocaine for nasal analgesia without impact on subsequent analysis of the ciliary motility.

Impact of local anesthesia on ciliary dyskinesia diagnosis by digital high-speed videomicroscopy

This prospective study investigates the impact of local anesthesia on ciliary function in nasal epithelium. The primary objective was to assess whether lidocaine 2% and naphazoline 0.5% nasal spray alter ciliary beat frequency and pattern in subjects undergoing nasal brushing, aiming to enhance primary ciliary dyskinesia (PCD) diagnosis.

HYPOTHESIS

It was hypothesized that local anesthesia administration would not significantly affect ciliary function in nasal epithelium.

STUDY DESIGN

A prospective, simple-blind randomized study was conducted between 2020 and 2023. The study employed digital high-speed videomicroscopy to analyze ciliary beat frequency and pattern.

PATIENT/SUBJECT SELECTION

A cohort of 38 participants was recruited, consisting of 25 healthy volunteers and 13 referred individuals (including seven diagnosed with PCD). Selection criteria ensured the absence of chronic respiratory diseases, recent respiratory tract infections, or regular use of nasal medications.

METHODOLOGY

Participants underwent nasal brushing with administration of lidocaine and naphazoline nasal spray in one nostril and saline in the contralateral nostril. Ciliary beat frequency and pattern were measured using digital high-speed video microscopy.

RESULTS

Nasal spray administration did not significantly alter ciliary beat frequency or pattern compared to saline (p = 0.841 and p = 0.125, respectively). Subgroup analysis revealed consistent results across healthy volunteers, referred patients, and PCD patients.

CONCLUSION

Local anesthesia with lidocaine and naphazoline spray did not affect ciliary function outcomes. These findings support the safe use of these agents in clinical practice for PCD diagnostic procedures. Further research with larger cohorts is warranted for validation.

Evidence for secondary ciliary dyskinesia in patients with cystic fibrosis

BACKGROUND

Mucociliary clearance (MCC) impairment can be due to mucus abnormalities or to a ciliary dysfunction, which can be innate, or secondary to infection and/or inflammation. In cystic fibrosis (CF), it is well documented that MCC is impaired due to mucus abnormalities, but little is known concerning ciliary beating. This study aimed to confirm that ciliary dyskinesia is present in CF, and if this might be innate or secondary to the chronic infection and/or inflammation.

METHODS

Ciliated epithelial samples were obtained by nasal brushing from 51 CF patients, and from 30 healthy subjects. Ciliary beating was evaluated using digital high-speed videomicroscopy at 37 °C, allowing to evaluate ciliary beat frequency (CBF) and the percentage of abnormal beat pattern (CBP); this was repeated after air-liquid interface (ALI) cell culture.

RESULTS

Ciliary dyskinesia was higher in CF patients than in healthy subjects, with a lower CBF and a higher percentage of abnormal CBP. Ciliary dyskinesia, already present in childhood, normalized after ALI cell culture. A chronic airway colonization did not worsen ciliary dyskinesia.

CONCLUSIONS

We showed that, in CF, a ciliary dyskinesia, present from childhood, might contribute to the impaired MCC. Our results also found that the abnormal ciliary beating was not associated with a chronic infection, and resolved after ALI cell culture, suggesting that ciliary dyskinesia in CF is not innate, and might be secondary to chronic inflammation.

Evaluation of Open-Source Ciliary Analysis Software in Primary Ciliary Dyskinesia: A Comparative Assessment

Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder characterized by alterations in motile cilia function. The diagnosis of PCD is challenging due to the lack of standardized methods in clinical practice. High-speed video microscopy analysis (HSVA) directly evaluates ciliary beat frequency (CBF) in PCD. Recently, open-source ciliary analysis software applications have shown promise in measuring CBF accurately. However, there is limited knowledge about the performance of different software applications, creating a gap in understanding their comparative effectiveness in measuring CBF in PCD. We compared two open-source software applications, CiliarMove (v219) and Cilialyzer (v1.2.1-b3098cb), against the manual count method. We used high-speed videos of nasal ciliary brush samples from PCD RSPH4A-positive (PCD (RSPH4A)) patients and healthy controls. All three methods showed lower median CBF values for patients with PCD (RSPH4A) than in healthy controls. CiliarMove and Cilialyzer identified lower CBF in patients with PCD (RSPH4A), similarly to the manual count. Cilialyzer, CiliarMove, and manual count methods demonstrated statistical significance (p-value < 0.0001) in the difference of median CBF values between patients with PCD (RSPH4A) and healthy controls. Correlation coefficients between the manual count values against both software methods demonstrated positive linear relationships. These findings support the utility of open-source software-based analysis tools. Further studies are needed to validate these findings with other genetic variants and identify the optimal software for accurate CBF measurement in patients with PCD.

Comparing region of interest selection and whole-field analysis for measurement of ciliary beat frequency in high-speed video analysis

BACKGROUND

Ciliary beat frequency (CBF) is crucial in mucociliary clearance. High-speed video analysis (HSVA) is commonly used to measure CBF but lacks standardization. We compared visual observation and computer-assisted calculation using fast Fourier transformation (FFT) in freshly collected bronchial ciliary epithelial cells and cultured cells.

METHODS

Bronchial epithelial cells were obtained from 12 patients who required bronchoscopic examination. Eighty-five videos of ciliary movement of freshly collected and cultured cells were recorded and used to calculate CBF using manual observation, region of interest (ROI) selection, and whole-field analysis.

RESULTS

CBF measured by the ROI selection method strongly correlated with that measured using manual observation, especially in freshly collected cells. However, 27.8% of the manual observation method values were doubled in the ROI selection method, probably because a round trip of cilia was calculated as two cycles and needed to be corrected to 1/2 value. Upon increasing the number of ROIs, the results of the ROI selection method came closer to that of WFA.

CONCLUSIONS

Computer-assisted calculation using FFT can aid in measuring CBF; however, current methods require visual confirmation. Further automated evaluation techniques are needed to establish more standardized and generalized CBF measurement methods using HSVA.

The Cilialyzer - A freely available open-source software for the analysis of mucociliary activity in respiratory cells

BACKGROUND AND OBJECTIVE

Primary ciliary dyskinesia (PCD) is a rare genetic disorder causing a defective ciliary structure, which predominantly leads to an impaired mucociliary clearance and associated airway disease. As there is currently no single diagnostic gold standard test, PCD is diagnosed by a combination of several methods comprising genetic testing and the examination of the ciliary structure and function. Among the approved diagnostic methods, only high-speed video microscopy (HSVM) allows to directly observe the ciliary motion and therefore, to directly assess ciliary function. In the present work, we present our recently developed freely available open-source software - termed "Cilialyzer", which has been specifically designed to support and facilitate the analysis of the mucociliary activity in respiratory epithelial cells captured by high-speed video microscopy.

METHODS

In its current state, the Cilialyzer software enables clinical PCD analysts to load, preprocess and replay recorded image sequences as well as videos with a feature-rich replaying module facilitating the commonly performed qualitative visual assessment of ciliary function (including the assessment of the ciliary beat pattern). The image processing methods made accessible through an intuitive user interface allow clinical specialists to comfortably compute the ciliary beating frequency (CBF), the activity map and the "frequency correlation length" - an observable getting newly introduced. Furthermore, the Cilialyzer contains a simple-to-use particle tracking interface to determine the mucociliary transport speed.

RESULTS

Cilialyzer is fully written in the Python programming language and freely available under the terms of the MIT license. The proper functioning of the computational analysis methods constituting the Cilialyzer software is demonstrated by using simulated and representative sample data from clinical practice. Additionally, the software was used to analyze high-speed videos showing samples obtained from healthy controls and genetically confirmed PCD cases (DNAI1 and DNAH11 mutations) to show its clinical applicability.

CONCLUSIONS

Cilialyzer serves as a useful clinical tool for PCD analysts and provides new quantitative information awaiting to be clinically evaluated using cohorts of PCD. As Cilialyzer is freely available under the terms of a permissive open-source license, it serves as a ground frame for further development of computational methods aiming at the quantification and automation of the analysis of mucociliary activity captured by HSVM.

Temporal Stability of Ciliary Beating Post Nasal Brushing, Modulated by Storage Temperature

Primary ciliary dyskinesia is a heterogeneous, inherited motile ciliopathy in which respiratory cilia beat abnormally, and some ultrastructural ciliary defects and specific genetic mutations have been associated with particular ciliary beating alterations. Ciliary beating can be evaluated using digital high-speed videomicroscopy (DHSV). However, normal reference values, essential to assess ciliary beating in patients referred for a PCD diagnostic, vary between centres, as minor variations in protocols might influence ciliary beating. Consequently, establishment of normal values is essential for each PCD diagnostic centre. We aimed to evaluate whether delay after sampling, and temperature for conservation of respiratory ciliated samples, might modify assessments of ciliary beating. In total, 37 healthy nasal brushing samples of respiratory ciliated epithelia were collected. Video sequences were recorded at 37 °C immediately using DHSV. Then, the samples were divided and conserved at 4 °C or at room temperature (RT). Ciliated beating edges were then recorded at 37 °C, at 3 h and at 9 h post sampling. In six samples, recordings were continued up to 72 h after sampling. Ciliary beating was assessed manually by ciliary beat frequency (CBFM) and ciliary beat pattern (CBP). A semi-automatic software was used for quantitative analysis. Both CBF and CBP evaluated manually and by a semi-automated method were stable 9 h after sampling. CBFM was higher when evaluated using samples stored at RT than at 4 °C. CBP and the semi-automated evaluation of ciliary beating were not affected by storage temperature. When establishing normal references values, ciliary beating can be evaluated at 37 °C up to 9 h after nasal brushing, but the storage temperature modifies ciliary beating and needs to be controlled.

Organ-based clues for diagnosis of inborn errors of immunity: A practical guide for clinicians

Inborn errors of immunity (IEI) comprise a group of about 490 genetic disorders that lead to aberrant functioning or the development of distinct immune system components. So far, a broad spectrum of IEI-related manifestations has been noted in the literature. Due to overlapping signs and symptoms of IEI, physicians face challenges in appropriately diagnosing and managing affected individuals. The last decade has witnesses improving in the molecular diagnosis of IEI patients. As a result, it can be the mainstay of diagnostic algorithms, prognosis, and possibly therapeutic interventions in patients with IEI. Furthermore, reviewing IEI clinical complications demonstrates that the manifestations and severity of the symptoms depend on the involved gene that causes the disease and its penetrance. Although several diagnostic criteria have been used for IEI, not every patient can be explored in the same way. As a result of the failure to consider IEI diagnosis and the variety of diagnostic capabilities and laboratory facilities in different regions, undiagnosed patients are increasing. On the other hand, early diagnosis is an almost essential element in improving the quality of life in IEI patients. Since there is no appropriate guideline for IEI diagnosis in different organs, focusing on the clues in the patient's chief complaint and physical exams can help physicians narrow their differential diagnosis. This article aims to provide a practical guide for IEI diagnosis based on the involved organ. We hope to assist clinicians in keeping IEI diagnosis in mind and minimizing possible related complications due to delayed diagnosis.

The RSPH4A Gene in Primary Ciliary Dyskinesia

The radial spoke head protein 4 homolog A (RSPH4A) gene is one of more than 50 genes that cause Primary ciliary dyskinesia (PCD), a rare genetic ciliopathy. Genetic mutations in the RSPH4A gene alter an important protein structure involved in ciliary pathogenesis. Radial spoke proteins, such as RSPH4A, have been conserved across multiple species. In humans, ciliary function deficiency caused by RSPH4A pathogenic variants results in a clinical phenotype characterized by recurrent oto-sino-pulmonary infections. More than 30 pathogenic RSPH4A genetic variants have been associated with PCD. In Puerto Rican Hispanics, a founder mutation (RSPH4A (c.921+3_921+6delAAGT (intronic)) has been described. The spectrum of the RSPH4A PCD phenotype does not include laterality defects, which results in a challenging diagnosis. PCD diagnostic tools can combine transmission electron microscopy (TEM), nasal nitric oxide (nNO), High-Speed Video microscopy Analysis (HSVA), and immunofluorescence. The purpose of this review article is to provide a comprehensive overview of current knowledge about the RSPH4A gene in PCD, ranging from basic science to human clinical phenotype.

Quantifying cilia beat frequency using high-speed video microscopy: Assessing frame rate requirements when imaging different ciliated tissues

Motile cilia are found in numerous locations throughout our body and play a critical role in various physiological processes. The most commonly used method to assess cilia motility is to quantify cilia beat frequency (CBF) via video microscopy. However, a large heterogeneity exists within published literature regarding the framerate used to image cilia motility for calculating CBF. The aim of this study was to determine the optimal frame rate required to image cilia motility for CBF assessment, and if the Nyquist theorem may be used to set this rate. One‐second movies of cilia were collected at >600 fps from mouse airways and ependyma at room‐temperature or 37°C. Movies were then down‐sampled to 30–300 fps. CBF was quantified for identical cilia at different framerates by either manual counting or automated MATLAB script. Airway CBF was significantly impaired in 30 fps movies, while ependymal CBF was significantly impaired in both 60 and 30 fps movies. Pairwise comparison showed that video framerate should be at least 150 fps to accurately measure CBF, with minimal improvement in CBF accuracy in movies >150 fps. The automated script was also found to be less accurate for measuring CBF in lower fps movies than manual counting, however, this difference disappeared in higher framerate movies (>150 fps). In conclusion, our data suggest the Nyquist theorem is unreliable for setting sampling rate for CBF measurement. Instead, sampling rate should be 3–4 times faster than CBF for accurate CBF assessment. Especially if CBF calculation is to be automated.