Comparison of ciliary wave disorders measured by image analysis and electron microscopy

Self-organization of self-clearing beating patterns in an array of locally interacting ciliated cells formulated as an adaptive Boolean network

The observed spatiotemporal ciliary beat patterns leading to proper mucociliary clearance on multiciliated epithelia are suspected to be the result of self-organizing processes on various levels. Here, we present a simplified pluricellular epithelium model, which intends to make the self-organization of ciliary beating patterns as well as of the associated fluid transport across the airway epithelium plausible. The model is based on a two-dimensional array of locally interacting oscillating ciliated cells. Ciliated cells are represented by Boolean actuators, and abstracted hydrodynamic mucociliary interactions are formulated in terms of logical update rules (Boolean functions). In the course of a simulation, initial random conformations of an array of actuators self-organize toward metachronally coordinated states exhibiting efficient transport of mucus. Within the framework of Boolean networks ciliated cells represent the nodes of the network and as the mucus establishes the local interactions among nodes, its distribution (together with the formulated local interactions) determines the topology of the network. Consequently, we propose to consider the dynamics on multiciliated epithelia in the context of adaptive (Boolean) networks. Furthermore, we would like to present insights gained from conducted comprehensive parameter studies. In particular, the dynamical response of the network with respect to variations of the boundary conditions, updating schemes (representing intercellular signaling mechanisms) and the proportion of ciliated cells is presented.

An Automated Measurement of Ciliary Beating Frequency using a Combined Optical Flow and Peak Detection

Objectives

The mucociliary transport system is a major defense mechanism of the respiratory tract. The performance of mucous transportation in the nasal cavity can be represented by a ciliary beating frequency (CBF). This study proposes a novel method to measure CBF by using optical flow.

Methods

To obtain objective estimates of CBF from video images, an automated computer-based image processing technique is developed. This study proposes a new method based on optical flow for image processing and peak detection for signal processing. We compare the measuring accuracy of the method in various combinations of image processing (optical flow versus difference image) and signal processing (fast Fourier transform [FFT] vs. peak detection [PD]). The digital high-speed video method with a manual count of CBF in slow motion video play, is the gold-standard in CBF measurement. We obtained a total of fifty recorded ciliated sinonasal epithelium images to measure CBF from the Department of Otolaryngology. The ciliated sinonasal epithelium images were recorded at 50-100 frames per second using a charge coupled device camera with an inverted microscope at a magnification of ×1,000.

Results

The mean square errors and variance for each method were 1.24, 0.84 Hz; 11.8, 2.63 Hz; 3.22, 1.46 Hz; and 3.82, 1.53 Hz for optical flow (OF) + PD, OF + FFT, difference image [DI] + PD, and DI + FFT, respectively. Of the four methods, PD using optical flow showed the best performance for measuring the CBF of nasal mucosa.

Conclusions

The proposed method was able to measure CBF more objectively and efficiently than what is currently possible.

Epithelium, cilia, and mucus: their importance in chronic rhinosinusitis

Chronic rhinosinusitis is a common disease resulting from inflammation of the sinonasal mucosa. It has long been recognized that patients with chronic rhinosinusitis have impaired capacity to clear sinonasal secretions. However, the cause of this pathologic process is not well understood. In this article the components of mucociliary clearance, including cilia, mucus production, and cilia beat frequency, are reviewed and alterations of the system discussed regarding contribution to the disease process.

[Value of nasal nitric oxide in the diagnosis of primary ciliary dyskinesia]

OBJECTIVE

The aim of this study is to report nasal nitric oxide (nNO) values in children with primary ciliary dyskinesia (PCD) and to compare them with nNO values in healthy children, asthmatic children, children with cystic fibrosis and children with post infectious bronchiectasis.

PATIENTS AND METHODS

We determined nNO values in 9 children with PCD, 36 asthmatic children, 31 children with cystic fibrosis, 8 children with post infectious bronchiectasis and 37 healthy children. We compared nNO values between these different conditions and calculated sensitivity and specificity of nNO to diagnose PCD.

RESULTS

All children with PCD - except one (nNO 348 ppb) - had nNO values below 112 ppb, mean 88 ppb (95%CI 9.6-166). The nNO mean was 898 ppb (95%CI 801-995) in healthy children, 1023 ppb (95%CI 911-1137) in asthmatic children, 438 ppb (95%CI 367-508) in cystic fibrosis children and 361 ppb (95%CI 252-470) in children with post infectious bronchiectasis. The mean concentration of nNO was lower (P<0.05) in PCD patients, compared to the other groups. The measurement of nasal NO in our study population showed, at a cut-off level of < or =112 ppb, a sensitivity of 88.9% and a specificity of 99.1% in the diagnosis of PCD [ROC 0.98 (95%CI 0.94-0.99); P<0.0001; probability ratio 95.1].

CONCLUSIONS

The measurement of nasal NO appears to be a useful tool for screening children for PCD, in which a cut-off level of < or =112 ppb suggests the disease, although nNO above 112 ppb does not exclude PCD.

Survival Time of Nasal Mucous Membrane Ciliated Cells: A Preliminary Study of Cytological Examination by Phase-Contrast Microscopy

The observation of the ciliated cell dynamics by phase-contrast microscope has allowed a profound study of some parameters of the cellular components. The aim of this preliminary study is to assess the surviving time of ciliary cells using the phase-contrast microscope. Nasal cytology was carried out on 50 healthy volunteers. The ciliary beat time was assessed by a video-camera connected with a PC. The time of ciliary beat persistence was extraordinarily long (mean 210 minutes, with range 74–1260). The ciliary activity remained valid as rhythm, synchronism and metachronality. In conclusion, this preliminary study demonstrated that cilia has an energetic autonomy of great importance, able to allow a valid functional activity also in the case of partial sufferance of the cellular unit.

Functional recovery of rabbit maxillary sinus mucosa in two different experimental injury models

OBJECTIVE/HYPOTHESIS

Ciliary wave disorder (CWD) is essential for effective mucociliary transport. The purpose of this study was to investigate morphologic and functional restoration in recovered sinus mucosa after 12 weeks of experimentally induced rhinosinusitis and regenerated sinus mucosa after mechanical injury.

STUDY DESIGN

Prospective study with animal models.

METHODS

Ten New Zealand white rabbits weighing between 2.5 and 3 kg were used for this experiment. In the recovered mucosa group (n = 5), the natural ostium of the maxillary sinus was closed with a synthetic sponge and removed 2 weeks later. In the regenerated sinus mucosa group (n = 5), maxillary sinus mucosa was stripped off through the anterior wall. Left sinus mucosae were used as controls. Twelve weeks postoperatively, ciliary beat frequency (CBF) and CWD were measured using an image analysis system. Morphologic changes in cilia were also observed using a scanning electron microscope (SEM).

RESULTS

The average CBFs in control, recovered, and regenerated mucosa were 13.21 +/- 3.66 Hz, 13.20 +/- 3.53 Hz, and 14.16 +/- 3.87 Hz, respectively. The average CWDs in these groups were 8.46 +/- 4.4, 21.04 +/- 14.73, and 24.43 +/- 19.2, respectively. SEM showed that loss of cilia and irregularities of ciliary arrangements were prominent in regenerated sinus mucosa.

CONCLUSION

Although 12 weeks is enough for morphologic regeneration of the ciliated epithelium after experimental sinusitis in rabbit maxillary sinuses, it does not appear long enough for full functional recovery. Restoration of CBFs does not equate to concurrent CWD restoration.

Mucociliary clearance – a critical upper airway host defense mechanism and methods of assessment

PURPOSE OF REVIEW

Mucociliary clearance is a critical host defense mechanism of the airways. Effective mucociliary clearance requires appropriate mucus production and coordinated ciliary activity. The important role of these two components is best demonstrated in disorders such as primary ciliary dyskinesia and cystic fibrosis, both of which lead to lifelong recurrent respiratory tract infections. We review the methods used to analyze mucociliary clearance.

RECENT FINDINGS

Utilization of microdialysis probes has improved temporal resolution of mucociliary clearance in murine airways, availing many genetic mouse models to critical mucociliary clearance analysis, while improved fixation technique for transmission electron microscopy has allowed for detailed resolution of the airway surface liquid. High-speed digital video analysis has improved quantification of ciliary beat frequency while advancements in air-liquid interface culturing techniques have generated in-vitro models to investigate mucociliary clearance.

SUMMARY

Advancements in techniques for analysis of mucociliary clearance have improved our understanding of the interaction between the respiratory epithelium and the airway surface liquid, resulting in the ability to study pathologic processes involving mucociliary clearance in great detail.