Ciliary function analysis for the diagnosis of primary ciliary dyskinesia: advantages of ciliogenesis in culture

Clinical implications of respiratory ciliary dysfunction in heterotaxy patients with congenital heart disease: elevated risk of postoperative airway complications

Objective

Cardiac surgery in Congenital Heart Disease-Heterotaxy (CHD-HTX) patients often leads to increased postoperative airway complications. Abnormal respiratory ciliary function, resembling primary ciliary dyskinesia, has been observed. We expanded the sample size by retrospectively reviewing Ciliary Dysfunction (CD) in CHD-HTX patients to verify the increased risk of post-surgical respiratory complications.

Methods

We conducted a retrospective review of 69 CHD-HTX patients undergoing cardiac surgery, assessing abnormal respiratory function using nasal nitric oxide (nNO) levels and nasal ciliary motion observed in video microscopy. Data collected included demographics, surgical details, postoperative complications, length of stay, ICU hours, salvage procedures, intubation duration, and mortality.

Results

The CD and no-CD cohorts exhibited notable similarities in risk adjustment in Congenital Heart Surgery-1 (RACHS-1) risk categories, age at the time of surgery, and the duration of follow-up evaluations. We observed a trend toward an increased length of post-operative stay in the CD group (15.0 vs. 14.0; P = 0.0017). CHD-HTX patients with CD showed significantly higher rates of respiratory complications (70% vs. 44.4%; P = 0.008). There were no notable variances observed in postoperative hospitalization duration, mechanical ventilation period, or surgical mortality.

Conclusion

Our findings suggest that CHD-HTX patients with CD may face an elevated risk of respiratory complications. These results offer guidance for perioperative management and serve as a reference for further pathological studies.

The Short Term Influence of Chest Physiotherapy on Lung Function Parameters in Children With Cystic Fibrosis and Primary Ciliary Dyskinesia

Airway clearance therapy (ACT) is one of the cornerstone treatment modalities to improve mucociliary clearance for patients with bronchiectasis. The progression of lung disease in patients with bronchiectasis can be evaluated by spirometry and multiple breath washout (MBW) and it is advised to monitor these on a regular basis. However, the short term effect of ACT on spirometry and MBW parameters is insufficiently clear and this variability may impact standardization. For cystic fibrosis (CF), available literature refutes a short time effect on spirometry and MBW parameters in children, however, for primary ciliary dyskinesia (PCD) no data are available. We performed a single-center, prospective cross-over study to evaluate the short term effect of a single ACT session using positive expiratory pressure mask on forced expiratory volume in 1 s (FEV₁) and lung clearance index (LCI), derived from MBW, compared to no ACT (control) in pediatric patients with CF and PCD. A total of 31 children were included: 14 with PCD and 17 with CF. For the whole group, there was no difference in median change of FEV₁ pp between the treatment and the control group (p 0.969), nor in median change of LCI (p 0.294). For the CF subgroup, the mean change in FEV₁ pp with ACT was -1.4% (range -9 to + 5) versus -0.2% (range -6 to + 5) for no ACT (p 0.271), the mean change in LCI with ACT was + 0.10 (range -0.7 to + 1.2) versus + 0.17 (range -0.5 to + 2.8) for no ACT (p 0.814). In the PCD subgroup, the mean change in FEV₁ pp with ACT was + 1.0 (range -7 to + 8) versus -0.3 (range -6 to + 5) for no ACT (p 0.293) and the mean change in LCI with ACT was -0.46 (range -3.7 to + 0.9) versus -0.11 (range -1.4 to + 1.3) for no ACT (p 0.178). There was no difference between PCD and CF for change in FEV₁ pp after ACT (p = 0.208), nor for LCI (p = 0.095). In this small group of pediatric patients, no significant short-term effect of chest physiotherapy on FEV₁ pp nor LCI in PCD and CF values nor variability was documented.

Stem Cell-derived Respiratory Epithelial Cell Cultures as Human Disease Models

Advances in stem cell biology and the understanding of factors that determine lung stem cell self-renewal have enabled long-term in vitro culture of human lung cells derived from airway basal and alveolar type II cells. Improved capability to expand and study primary cells long term, including in clonal cultures that are recently derived from a single cell, will allow experiments that address fundamental questions about lung homeostasis and repair, as well as translational questions in asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and lung cancer research. Here, we provide a brief history of postnatal lung epithelial cell culture and describe recent methodological advances. We further discuss the applications of primary cultures in defining "normal" epithelium, in modeling lung disease, and in future cell therapies.

Respiratory Cilia as a Therapeutic Target of Phosphodiesterase Inhibitors

Mucociliary clearance is an essential airway defense mechanism dependent predominantly on the proper ciliary function and mucus rheology. The crucial role of cilia is evident in `a variety of respiratory diseases, as the ciliary dysfunction is associated with a progressive decline in lung function over time. The activity of cilia is under supervision of multiple physiological regulators, including second messengers. Their role is to enable a movement in coordinated metachronal waves at certain beat frequency. Ciliary function can be modulated by various stimuli, including agents from the group of beta₂ agonists, cholinergic drugs, and adenosine triphosphate (ATP). They trigger cilia to move faster in response to elevated cytoplasmic Ca²⁺ originated from intracellular sources or replenished from extracellular space. Well-known cilia-stimulatory effect of Ca²⁺ ions can be abolished or even reversed by modulating the phosphodiesterase (PDE)-mediated breakdown of cyclic adenosine monophosphate (cAMP) since the overall change in ciliary beating has been dependent on the balance between Ca²⁺ ions and cAMP. Moreover, in chronic respiratory diseases, high ATP levels may contribute to cAMP hydrolysis and thus to a decrease in the ciliary beat frequency (CBF). The role of PDE inhibitors in airway cilia-driven transport may help in prevention of progressive loss of pulmonary function often observed despite current therapy. Furthermore, administration of selective PDE inhibitors by inhalation lowers the risk of their systemic effects. Based on this review we may conclude that selective (PDE1, PDE4) or dual PDE inhibitors (PDE3/4) increase the intracellular level of cyclic nucleotides in airway epithelial cells and thus may be an important target in the development of new inhaled mucokinetic agents. Further research is required to provide evidence of their effectiveness and feasibility regarding their cilia-modulating properties.

Unveiling the genetic etiology of primary ciliary dyskinesia: When standard genetic approach is not enough

PURPOSE

Primary ciliary dyskinesia (PCD) is a ciliopathy caused by dysfunction of motile cilia. As there is still no standard PCD diagnostics, the final diagnosis requires a combination of several tests. The genetic screening is a hallmark for the final diagnosis and requires high-throughput techniques, such as whole-exome sequencing (WES). Nevertheless, WES has limitations that may prevent a definitive genetic diagnosis. Here we present a case that demonstrates how the PCD genetic diagnosis may not be trivial.

MATERIALS/METHODS

A child with PCD and situs inversus totalis (designated as Kartagener syndrome (KS)) was subjected to clinical assessments, ultrastructural analysis of motile cilia, extensive genetic evaluation by WES and chromosomal array analysis, bioinformatic analysis, gene expression analysis and immunofluorescence to identify the genetic etiology. His parents and sister, as well as healthy controls were also evaluated.

RESULTS

Here we show that a disease-causing variant in the USP11 gene and copy number variations in CRHR1 and KRT34 genes may be involved in the patient PCD phenotype. None of these genes were previously reported in PCD patients and here we firstly show its presence and immunolocalization in respiratory cells.

CONCLUSIONS

This work highlights how the genetic diagnosis can turn to be rather complex and that combining several approaches may be needed. Overall, our results contribute to increase the understanding of the genetic factors involved in the pathophysiology of PCD/KS, which is of paramount importance to assist the current diagnosis and future development of newer therapies.

Ciliary functional analysis: Beating a path towards standardization

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.

Quantifying Ciliary Dynamics during Assembly Reveals Stepwise Waveform Maturation in Airway Cells

Motile cilia are essential for clearance of particulates and pathogens from airways. For effective transport, ciliary motor proteins and axonemal structures interact to generate the rhythmic, propulsive bending, but the mechanisms that produce a dynamic waveform remain incompletely understood. Biomechanical measures of human ciliary motion and their relationships to ciliary assembly are needed to illuminate the biophysics of normal ciliary function and to quantify dysfunction in ciliopathies. To these ends, we analyzed ciliary motion by high-speed video microscopy of ciliated cells sampled from human lung airways compared with primary culture cells that undergo ciliogenesis in vitro. Quantitative assessment of waveform parameters showed variations in waveform shape between individual cilia; however, general trends in waveform parameters emerged, associated with progression of cilia length and stage of differentiation. When cilia emerged from cultured cells, beat frequency was initially elevated, then fell and remained stable as cilia lengthened. In contrast, the average bending amplitude and the ability to generate force gradually increased and eventually approached values observed in ex vivo samples. Dynein arm motor proteins DNAH5, DNAH9, DNAH11, and DNAH6 were localized within specific regions of the axoneme in the ex vivo cells; however, distinct stages of in vitro waveform development identified by biomechanical features were associated with the progressive movement of dyneins to the appropriate proximal or distal sections of the cilium. These observations suggest that the stepwise variation in waveform development during ciliogenesis is dependent on cilia length and potentially on outer dynein arm assembly.

Motile Ciliary Disorders in Chronic Airway Inflammatory Diseases: Critical Target for Interventions

PURPOSE OF REVIEW

Impaired mucociliary clearance has been implicated in chronic upper and lower airway inflammatory diseases (i.e., allergic and non-allergic rhinitis, chronic rhinosinusitis with or without nasal polyps and asthma). How motile ciliary disorders (impaired ciliogenesis, ciliary beating and ultrastructural defects) are implicated in chronic airway inflammatory diseases is not fully understood. Elaboration of the role of motile ciliary disorders may serve as therapeutic targets for improving mucociliary clearance, thereby complementing contemporary disease management.

RECENT FINDINGS

We have summarized the manifestations of motile ciliary disorders and addressed the underlying associations with chronic airway inflammatory diseases. A panel of established and novel diagnostic tests and therapeutic interventions are outlined. Physicians should be vigilant in screening for motile ciliary disorders, particularly in patients with co-existing upper and lower airway inflammatory diseases. Proper assessment and treatment of motile ciliary disorders may have added value to the management and prevention of chronic airway inflammatory diseases.

Diagnosis of primary ciliary dyskinesia: When and how?

INTRODUCTION

Primary ciliary dyskinesia (PCD) is a rare congenital disorder involving permanent ubiquitous structural and/or functional ciliary abnormalities.

METHODS

A single-center retrospective study included 56 cases of PCD (respiratory form) out of a cohort of 280 patients with suspected PCD. The main features of history-taking and clinical examination were analyzed, to formulate a pragmatic diagnostic procedure, easy to implement in clinical practice.

RESULTS

Chronic respiratory tract infectious symptoms are sensitive but non-specific for the diagnosis of PCD. Nasal brushing for phase-contrast microscopy study of ciliary morphology and activity proved to be a fast, easy, non-invasive, cost-effective and age-independent diagnostic method. In doubtful cases, depending on local availability, further tests are indicated: nasal nitric oxide level, electronic microscopy, genetic study and cell culture.

CONCLUSIONS

In suspected PCD, there being no gold standard method of screening and early diagnosis, nasal brushing with ciliary study is contributive, alongside numerous other complementary tests, on condition that the clinician is experienced and results are interpreted in the light of clinical examination and history-taking.

Patient-specific three-dimensional explant spheroids derived from human nasal airway epithelium: a simple methodological approach for ex vivo studies of primary ciliary dyskinesia

BACKGROUND

Three-dimensional explant spheroid formation is an ex vivo technique previously used in studies of airway epithelial ion and water transport. Explanted cells and sheets of nasal epithelium form fully differentiated spheroids enclosing a partly fluid-filled lumen with the ciliated apical surface facing the outside and accessible for analysis of ciliary function.

METHODS

We performed a two-group comparison study of ciliary beat pattern and ciliary beat frequency in spheroids derived from nasal airway epithelium in patients with primary ciliary dyskinesia (PCD) and in healthy controls. Nasal ciliary cells and sheets were removed on day 1 by nasal brush biopsy and analyzed with regard to ciliary beat pattern-and frequency using high-speed video imaging for standard reference values. Three-dimensional explant spheroid formation was initiated in the same individual on the same day by incubation of cells and sheets from a separate brush biopsy. Harvested spheroids were analyzed earliest possible and values of spheroid ciliary beat pattern and frequency were compared to the corresponding reference values from day 1.

RESULTS

Spheroids formed fast in serum-free culture medium. Formation was successful in 15 out of 18 (82%) sampled individuals. Thus, formation was successful in seven healthy controls and eight PCD patients, while unsuccessful in 3 with PCD due to infection. Median (range) number of days in culture before harvesting of spheroids was 4 (1-5) in healthy versus 2 (1-5) in PCD. Spheroid ciliary beat pattern and frequency were unchanged compared to their corresponding day 1 standard reference values. Spheroid ciliary beat frequency discriminated highly significant between healthy controls (9.3 Hz) and PCD patients (2.4 Hz) (P < 0.0001). Survival of spheroids was 16 days in a single healthy person.

CONCLUSION

Patient-specific three-dimensional explant spheroid formation from a minimal invasive nasal brush biopsy is a feasible, fast and valid ex vivo method to assess ciliary function with potential of aiding the diagnosis of PCD. In addition, it may be a useful model in the investigation of pathophysiological aspects and drug effects in human nasal airway epithelium.

European Respiratory Society guidelines for the diagnosis of primary ciliary dyskinesia

The diagnosis of primary ciliary dyskinesia is often confirmed with standard, albeit complex and expensive, tests. In many cases, however, the diagnosis remains difficult despite the array of sophisticated diagnostic tests. There is no "gold standard" reference test. Hence, a Task Force supported by the European Respiratory Society has developed this guideline to provide evidence-based recommendations on diagnostic testing, especially in light of new developments in such tests, and the need for robust diagnoses of patients who might enter randomised controlled trials of treatments. The guideline is based on pre-defined questions relevant for clinical care, a systematic review of the literature, and assessment of the evidence using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. It focuses on clinical presentation, nasal nitric oxide, analysis of ciliary beat frequency and pattern by high-speed video-microscopy analysis, transmission electron microscopy, genotyping and immunofluorescence. It then used a modified Delphi survey to develop an algorithm for the use of diagnostic tests to definitively confirm and exclude the diagnosis of primary ciliary dyskinesia; and to provide advice when the diagnosis was not conclusive. Finally, this guideline proposes a set of quality criteria for future research on the validity of diagnostic methods for primary ciliary dyskinesia.

Cystic Fibrosis and Other Respiratory Diseases of Impaired Mucus Clearance

Exposed to a diverse array of potentially noxious agents, the respiratory tract is protected by a highly developed innate defense system. Physiologically regulated epithelial ion and water transport coordinated with mucin secretion, beating cilia, and cough results in continuous flow of fluid and mucus over airway surfaces toward the larynx. This cleansing action is the initial and perhaps most quantitatively important innate defense mechanism. Repeated lung infections and eventual respiratory insufficiency characteristic of human cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) illustrate the consequences of impaired mucus clearance. Altered mucus clearance likely contributes to the initiation, progression, and chronicity of other airway diseases characterized by inflammation and mucous secretory cell hyper/metaplasia that afflict millions worldwide, including chronic obstructive pulmonary disease (COPD). This review concisely discusses the pathophysiology of human diseases characterized by genetic defects that impair mucus clearance. It then explores animal models in which components of the mucus clearance system have been disrupted. These models firmly establish the importance of mucus clearance for respiratory health, and will help elucidate disease mechanisms and therapeutic strategies in CF, PCD and COPD.

Diagnostic Methods in Primary Ciliary Dyskinesia

Diagnosing primary ciliary dyskinesia is difficult. With no reference standard, a combination of tests is needed; most tests require expensive equipment and specialist scientists. We review the advances in diagnostic testing over the past hundred years, with emphasis on recent advances. We particularly focus on use of high-speed video analysis, transmission electron microscopy, nasal nitric oxide and genetic testing. We discuss the international efforts that are in place to advance the evidence base for diagnostic tests.

Accuracy of diagnostic testing in primary ciliary dyskinesia

Diagnosis of primary ciliary dyskinesia (PCD) lacks a “gold standard” test and is therefore based on combinations of tests including nasal nitric oxide (nNO), high-speed video microscopy analysis (HSVMA), genotyping and transmission electron microscopy (TEM). There are few published data on the accuracy of this approach.

Using prospectively collected data from 654 consecutive patients referred for PCD diagnostics we calculated sensitivity and specificity for individual and combination testing strategies. Not all patients underwent all tests.

HSVMA had excellent sensitivity and specificity (100% and 93%, respectively). TEM was 100% specific, but 21% of PCD patients had normal ultrastructure. nNO (30 nL·min⁻¹ cut-off) had good sensitivity and specificity (91% and 96%, respectively). Simultaneous testing using HSVMA and TEM was 100% sensitive and 92% specific.

In conclusion, combination testing was found to be a highly accurate approach for diagnosing PCD. HSVMA alone has excellent accuracy, but requires significant expertise, and repeated sampling or cell culture is often needed. TEM alone is specific but misses 21% of cases. nNO (≤30 nL·min⁻¹) contributes well to the diagnostic process. In isolation nNO screening at this cut-off would miss ∼10% of cases, but in combination with HSVMA could reduce unnecessary further testing. Standardisation of testing between centres is a future priority.

Combination testing in PCD diagnosis remains the most accurate approach, but standardisation is neededhttp://ow.ly/TLEDu

Lung structure-function correlation in patients with primary ciliary dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare disease, characterised by chronic airway infection. In cystic fibrosis, FEV1 is insensitive to detect patients with structural damage, and Lung Clearance Index (LCI) was proposed as a better marker of early lung damage. In PCD, the relationship between functional and structural abnormalities has been less studied. We aimed to re-examine this in a cohort of children and adults with mild to moderate PCD.

METHODS

Thirty-eight patients with PCD (5.2-25.0 years) and 70 healthy controls (4.4-25.8 years) were recruited to compare LCI, measured by N2 multiple breath washout and FEV1 in a prospective observational trial. In a subset of 30 patients who underwent chest imaging, structural abnormalities were evaluated with cystic fibrosis computed tomography (CFCT) scores.

RESULTS

LCI was abnormal in 28 of 38 patients and a moderate correlation was observed between LCI and FEV1 (r=-0.519, p=0.001). Moreover, LCI correlated well with CFCT total score (r=0.800, p<0.001) and also with subscores for airway wall thickening (r=0.809, p<0.001), mucus plugging (r=0.720, p<0.001) and bronchiectasis (r=0.494, p<0.001). Concordance was seen between LCI and CFCT in 25 of 30 (83%) patients, but between FEV1 and CFCT in only 16 of 30 (53%) patients. LCI was more sensitive (90.9%, 95% CI 70.8 to 98.6) to detect patients with structural abnormalities than FEV1 (36.4%, 95% CI 17.2 to 59.3).

CONCLUSIONS

We demonstrated that measuring LCI in patients with PCD is of clinical relevance; it was more frequently abnormal than FEV1, correlated well with CFCT and was more sensitive than FEV1 to detect patients with structural abnormalities.

A new tool improves diagnostic test performance for transmission em evaluation of axonemal dynein arms

Abstract Diagnosis of primary ciliary dyskinesia (PCD) by identification of dynein arm loss in transmission electron microscopy (TEM) images can be confounded by high background noise due to random electron-dense material within the ciliary matrix, leading to diagnostic uncertainty even for experienced morphologists. The authors developed a novel image analysis tool to average the axonemal peripheral microtubular doublets, thereby increasing microtubular signal and reducing random background noise. In a randomized, double-blinded study that compared two experienced morphologists and three different diagnostic approaches, they found that use of this tool led to improvement in diagnostic TEM test performance.

Primary Ciliary Dyskinesia: An Update on New Diagnostic Modalities and Review of the Literature

Primary ciliary dyskinesia (PCD) is a genetic condition affecting approximately 1 in 15,000-20,000 individuals, and the majority of cases exhibit an autosomal recessive inheritance pattern. However, genetic heterogenicity is seen in PCD and reflects the complexity of ciliary structure and biogenesis. There have been many recent advances in the diagnosis and management of PCD in the last few years, including advanced genetic sequencing, nasal nitric oxide assay, and ciliary motility tests. This article focuses on the ultrastructure and pathophysiology of ciliary dyskinesias, along with a review of clinical features, screening, and diagnostic tests. It also reflects upon the diagnostic challenge caused by the diverse clinical presentation, which will be of great value to pediatricians for considering PCD in their differential list, henceforth leading to early recognition and management, along with awareness of the recent advances in the field of genetics and other techniques for diagnosis of this condition.

Diagnostic accuracy of nitric oxide measurements to detect primary ciliary dyskinesia

BACKGROUND

Primary Ciliary Dyskinesia (PCD) is an orphan disease characterized by recurrent respiratory infections and an increased prevalence of situs inversus and male infertility. Low nasal Nitric Oxide (nNO) is used as a new test to diagnose PCD. The test sensitivity is good, but specificity has not been studied widely. Therefore, we evaluated the diagnostic accuracy of low nNO to diagnose PCD in a large cohort, including healthy patients and different disease controls.

MATERIALS AND METHODS

Nasal nitric oxide was measured during plateau exhalation against resistance (nNOplat) and during tidal breathing (nNOtid). Moreover, we measured fractional exhaled NO (FENO). We included 226 patients: 38 with PCD, 49 healthy controls, and 139 disease controls (cystic fibrosis, humoral immunodeficiency, and asthma).

RESULTS

The nNOplat cut-off value of 300 ppb provided the best sensitivity (89·5%) and specificity (87·3%) to detect PCD. There was overlap between PCD and disease controls: 16·5% of disease controls had a false-positive result. nNOtid correlated with nNOplat (r=0·912), but values differed (P=0·0001). The nNOtid cut-off of 200 ppb had a sensitivity of 89·5% and a specificity of 80·6% to detect PCD. The FENO cut-off of 10 ppb had an acceptable sensitivity (89·5%), but a low specificity (58·3%). Positive and negative likelihood ratios were suboptimal for all tests.

CONCLUSIONS

nNOplat, nNOtid and FENO measurements overlap between PCD and disease controls. Sensitivity is comparable for the three tests. Applying composite scores slightly improves diagnostic accuracy. Given the less than 90% test sensitivity, PCD should be considered in patients with intermediate results.

Primary ciliary dyskinesia and humoral immunodeficiency--is there a missing link?

BACKGROUND

Primary ciliary dyskinesia (PCD) and humoral mmunodeficiency (HID) are both rare disorders which cause recurrent upper and lower respiratory tract infections.

OBJECTIVE

To examine the concurrence of PCD and HID in a patient cohort with known PCD.

METHODS

Retrospective review of the patient files.

RESULTS

We describe 11 patients of a cohort of 168 patients with PCD (6.5%) with a combination of PCD and some form of HID. The patients all presented with typical clinical symptoms for PCD, however the role of the concomitant immunological abnormalities is not clear.

CONCLUSION

PCD and HID coincided in 6.5% of the patients. We suggest that a common pathophysiological pathway results in both disorders.

Culture of primary ciliary dyskinesia epithelial cells at air-liquid interface can alter ciliary phenotype but remains a robust and informative diagnostic aid

Background

The diagnosis of primary ciliary dyskinesia (PCD) requires the analysis of ciliary function and ultrastructure. Diagnosis can be complicated by secondary effects on cilia such as damage during sampling, local inflammation or recent infection. To differentiate primary from secondary abnormalities, re-analysis of cilia following culture and re-differentiation of epithelial cells at an air-liquid interface (ALI) aids the diagnosis of PCD. However changes in ciliary beat pattern of cilia following epithelial cell culture has previously been described, which has brought the robustness of this method into question. This is the first systematic study to evaluate ALI culture as an aid to diagnosis of PCD in the light of these concerns.

Methods

We retrospectively studied changes associated with ALI-culture in 158 subjects referred for diagnostic testing at two PCD centres. Ciliated nasal epithelium (PCD n = 54; non-PCD n = 111) was analysed by high-speed digital video microscopy and transmission electron microscopy before and after culture.

Results

Ciliary function was abnormal before and after culture in all subjects with PCD; 21 PCD subjects had a combination of static and uncoordinated twitching cilia, which became completely static following culture, a further 9 demonstrated a decreased ciliary beat frequency after culture. In subjects without PCD, secondary ciliary dyskinesia was reduced.

Conclusions

The change to ciliary phenotype in PCD samples following cell culture does not affect the diagnosis, and in certain cases can assist the ability to identify PCD cilia.

Primary ciliary dyskinesia: critical evaluation of clinical symptoms and diagnosis in patients with normal and abnormal ultrastructure

Background

Primary ciliary dyskinesia (PCD) is a rare disorder with variable disease progression. To date, mutations in more than 20 different genes have been found. At present, PCD subtypes are described according to the ultrastructural defect on transmission electron microscopy (TEM) of the motile cilia. PCD with normal ultrastructure (NU) is rarely reported because it requires additional testing. Biallelic mutations in DNAH11 have been described as one cause of PCD with NU.

The aim of our study was to describe the clinical characteristics of a large population of patients with PCD, in relation to the ultrastructural defect. Additionally, we aimed to demonstrate the need for biopsy and cell culture to reliably diagnose PCD, especially the NU subtype.

Methods

We retrospectively analyzed data from 206 patients with PCD. We compared the clinical characteristics, lung function, microbiology and imaging results of 68 patients with PCD and NU to those of 90 patients with dynein deficiencies and 41 patients with central pair abnormalities. In addition, we aimed to demonstrate the robustness of the diagnosis of the NU subtype in cell culture by data from genetic analysis.

Results

PCD with NU comprised 33% (68/206) of all patients with PCD. Compared to other subtypes, patients with PCD and NU had a similar frequency of upper and lower respiratory tract problems, as well as similar lung function and imaging. With the currently widely applied approach, without cell culture, the diagnosis would have been missed in 16% (11/68) of patients with NU. Genetic analysis was performed in 29/68 patients with PCD and NU, and biallelic mutations were found in 79% (23/29) of tested patients.

Conclusions

We reported on the clinical characteristics of a large population of patients with PCD and NU. We have shown that systematic performance of biopsy and cell culture increases sensitivity to detect PCD, especially the subtype with NU.

PCD with NU has similar clinical characteristics as other PCD types and requires biopsy plus ciliogenesis in culture for optimal diagnostic yield.

Impact of cilia ultrastructural examination on the diagnosis of primary ciliary dyskinesia

Ultrastructural examination of cilia is the "gold standard" for diagnosing primary ciliary dyskinesia. There is little evidence suggesting the most effective method of procuring a ciliary biopsy and scant benchmark data on rates of conclusive biopsies or on the diagnostic impact of such biopsies. To critically assess rates of inconclusive, positive, and negative ciliary biopsies and to identify clinical factors associated with conclusive results, we reviewed ciliary biopsies submitted for electron microscopy from 2006 to 2011, noting whether specimens were adequate for analysis and whether the ciliary structure was normal. The biopsy site, method used, procedurist's specialty, and clinical diagnoses were determined. Biopsy findings were categorized by diagnostic impact. Over 5 years, 187 patients had 211 biopsies. Conclusive results were obtained on 133/211 biopsies (63%); the remainder were insufficient. The rate of inconclusive biopsies did not vary significantly (P > 0.05; Fisher's exact) among sampling methods. Abnormal results were identified in 8/133 (6.0%) of the adequate specimens. Forceps compared to brush biopsies (abnormal in 4/12 versus 4/121 of the adequate specimens, P  =  0.002), along with multiple biopsy samples (taken on same or different days) compared with a single biopsy sample (abnormal in 3/12 versus 1/110 of the adequate specimens, P  =  0.01), were more likely to yield an abnormal result. Only 63% of pediatric ciliary biopsies provide adequate morphology for analysis, the large majority of these samples showing normal ciliary anatomy. The method of obtaining biopsies did not significantly affect result conclusiveness. Understanding the diagnostic impact of ultrastructural analysis is important as new diagnostic algorithms are developed for primary ciliary dyskinesia.

Primary ciliary dyskinesia, an orphan disease

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disease, caused by specific primary structural and/or functional abnormalities of the motile cilia, in contrast with the transitory abnormalities seen in secondary ciliary dyskinesia. Disease-causing mutations in at least 16 genes have already been identified. The true incidence of PCD may be higher than currently reported, because the diagnosis is challenging and often missed. For the confirmation of PCD, both ciliary motility as well as ciliary ultrastructure must be evaluated. An early and adequate diagnosis and therapy can theoretically prevent bronchiectasis. Measurement of nasal nitric oxide has some value as a screening test but cannot be performed in young children. In the respiratory tract epithelium, impaired mucociliary clearance leads to chronic and/or recurrent upper and lower respiratory tract infections. In up to 75 % of the patients, respiratory manifestations start in the newborn period, although the diagnosis is often missed at that time. During embryogenesis, nodal cilia, which are motile cilia, determine the correct lateralization of the organs. Dysfunction of these cilia leads to random lateralization and thus situs inversus in approximately 50 % of the patients with PCD. The tail of a spermatozoon has a structure similar to that of a motile cilium. Consequently, male infertility due to immotile spermatozoa is often part of the characteristics of PCD. Given the heterogeneity and the rarity of the disorder, therapy is not evidence-based. Many treatment schedules are proposed in analogy with the treatment for cystic fibrosis.

CONCLUSION

Respiratory infections, situs inversus and male infertility are typical manifestations of PCD, a rare autosomal recessive disorder.

Splice-site mutations in the axonemal outer dynein arm docking complex gene CCDC114 cause primary ciliary dyskinesia

Defects in motile cilia and sperm flagella cause primary ciliary dyskinesia (PCD), characterized by chronic airway disease, infertility, and left-right laterality disturbances, usually as a result of loss of the outer dynein arms (ODAs) that power cilia/flagella beating. Here, we identify loss-of-function mutations in CCDC114 causing PCD with laterality malformations involving complex heart defects. CCDC114 is homologous to DCC2, an ODA microtubule-docking complex component of the biflagellate alga Chlamydomonas. We show that CCDC114 localizes along the entire length of human cilia and that its deficiency causes a complete absence of ciliary ODAs, resulting in immotile cilia. Thus, CCDC114 is an essential ciliary protein required for microtubular attachment of ODAs in the axoneme. Fertility is apparently not greatly affected by CCDC114 deficiency, and qPCR shows that this may explained by low transcript expression in testis compared to ciliated respiratory epithelium. One CCDC114 mutation, c.742G>A, dating back to at least the 1400s, presents an important diagnostic and therapeutic target in the isolated Dutch Volendam population.

Diagnostic tools in Rhinology EAACI position paper

This EAACI Task Force document aims at providing the readers with a comprehensive and complete overview of the currently available tools for diagnosis of nasal and sino-nasal disease. We have tried to logically order the different important issues related to history taking, clinical examination and additional investigative tools for evaluation of the severity of sinonasal disease into a consensus document. A panel of European experts in the field of Rhinology has contributed to this consensus document on Diagnostic Tools in Rhinology.

Safety assessment of thiolated polymers: effect on ciliary beat frequency in human nasal epithelial cells

OBJECTIVE

The aim of this study was to investigate the nasal safety of gel formulations of thiolated polymers (thiomers) by assessing their effect on ciliary beat frequency (CBF) in human nasal epithelial cells.

METHODS

Poly(acrylic acid) 450 kDa-cysteine (PAA-cys) and alginate-cysteine (alg-cys) were synthesized by covalent attachment of L-cysteine to the polymeric backbone. The cationic polymer chitosan-thiobutylamidine (chito-TBA) was synthesized by attaching iminothiolane to chitosan. CBF using was measured by a photometric system. CBF was measured before incubating the cells with test gels, during incubation and after washing out the polymeric test gels to evaluate reversibility of cilio-inhibition. The influence of viscosity on CBF was determined by using hydroxyethylcellulose (HEC)-gels of various concentrations.

RESULTS

Ciliary beating was observed to be affected by viscosity, but cilia were still beating in the presence of a HEC-gel displaying an apparent viscosity of 25 Pa.s. In case of thiolated polymers and their unmodified control, a concentration-dependent decrease in CBF could be observed. PAA-cys, alg-cys, chito-TBA and their corresponding unmodified controls exhibited a moderate cilio-inhibitory effect, followed by a partial recovery of CBF when used at a concentration of 1%. Alg-cys 2% and chito-TBA 2% (m/v) gels exhibited severe cilio-inhibition, which was partially reversible. L-cysteine and reduced glutathione led to mild cilio-inhibition at concentrations of 3% (m/v).

CONCLUSIONS

Taking into account that dilution after application and cilio-modifying effects is usually more pronounced under in vitro conditions, thiomers can be considered as suitable excipients for nasal drug delivery systems.

Primary ciliary dyskinesia: evaluation using cilia beat frequency assessment via spectral analysis of digital microscopy images

Ciliary beat frequency (CBF) measurements provide valuable information for diagnosing of primary ciliary dyskinesia (PCD). We developed a system for measuring CBF, used it in association with electron microscopy to diagnose PCD, and then analyzed characteristics of PCD patients. The CBF measurement system was based on power spectra measured through digital imaging. Twenty-four patients suspected of having PCD (age 1-19 yr) were selected from a group of 75 children and adolescents with pneumopathies of unknown causes. Ten healthy, nonsmoking volunteers (age ≥ 17 yr) served as a control group. Nasal brush samples were collected, and CBF and electron microscopy were performed. PCD was diagnosed in 12 patients: 5 had radial spoke defects, 3 showed absent central microtubule pairs with transposition, 2 had outer dynein arm defects, 1 had a shortened outer dynein arm, and 1 had a normal ultrastructure. Previous studies have reported that the most common cilia defects are in the dynein arm. As expected, the mean CBF was higher in the control group (P < 0.001) and patients with normal ultrastructure (P < 0.002), than in those diagnosed with cilia ultrastructural defects (i.e., PCD patients). An obstructive ventilatory pattern was observed in 70% of the PCD patients who underwent pulmonary function tests. All PCD patients presented bronchial wall thickening on chest computed tomography scans. The protocol and diagnostic techniques employed allowed us to diagnose PCD in 16% of patients in this study.

Physiology and pathophysiology of respiratory mucosa of the nose and the paranasal sinuses

In this review, anatomy and physiology of the respiratory mucosa of nose and paranasal sinuses are summarized under the aspect of its clinical significance. Basics of endonasal cleaning including mucociliary clearance and nasal reflexes, as well as defence mechanisms are explained. Physiological wound healing, aspects of endonasal topical medical therapy and typical diagnostic procedures to evaluate the respiratory functions are presented. Finally, the pathophysiologies of different subtypes of non-allergic rhinitis are outlined together with treatment recommendations.

Ultrastructural abnormalities of respiratory cilia: a 25-year experience

CONTEXT

Ciliary dyskinesia is a rare, but significant, cause of chronic respiratory infections, and transmission electron microscopy is a critical adjunct to making the diagnosis.

OBJECTIVE

To investigate a single institution's experience with patients demonstrating abnormal ciliary ultrastructure.

DESIGN

Retrospective clinicopathologic review of 278 bronchial or nasal turbinate brushings or biopsies from 1983 through 2007.

RESULTS

There were 12 women and 9 men (mean age, 19.6 years; range, 1-54 years) with abnormal ciliary ultrastructure. Clinical history was unavailable in 3 patients, 15 (83%) of 18 patients presented with chronic or recurrent upper respiratory infections, and 3 (17%) presented with infertility. Seven (39%) of 18 patients had findings of Kartagener syndrome with situs inversus, dextrocardia, and bronchiectasis. Truncation or absence of inner or outer dynein arms occurred in 15 (71%) of 21 cases, and 5 (24%) revealed transposition defects with displacement of the central microtubules and peripheral doublets in 9 + 0 and 8 + 1 patterns. Radial spoke defects with microtubular disarray occurred in 4 (19%) of 21 cases. Compound cilia with multiple axonemes within a single outer sheath and supernumerary microtubules each occurred in 2 (10%) of the cases. Random ciliary orientation was also found in 2 (10%) of the cases, and dense granular basal body inclusions occurred in 1 case (5%). Multiple abnormalities occurred in 6 (29%) of the 21 cases.

CONCLUSIONS

Most patients presented with chronic respiratory tract infections or infertility. Dynein arm defects, transposition defects, and radial spoke defects were the most commonly encountered abnormal findings. Less-frequent abnormal findings included compound cilia, supernumerary microtubules, and dense granular basal body inclusions.

Discinesia ciliar primária: quando o pediatra deve suspeitar e como diagnosticar?

OBJETIVO: Revisar a discinesia ciliar primária (DCP) quanto aos seus aspectos ultra-estruturais, discriminar os defeitos ciliares primários dos secundários, descrever o quadro clínico, os testes laboratoriais de triagem e de diagnóstico disponíveis, bem como seu manejo clínico. FONTE DE DADOS: Pesquisa nas bases de dados Medline, Lilacs e SciELO, no período de 1980 a 2007. SÍNTESE DOS DADOS: A DCP é uma doença autossômica recessiva que compromete a estrutura e/ou a função ciliar e, conseqüentemente, o transporte mucociliar. As manifestações clínicas envolvem o trato respiratório superior e inferior, com infecções recorrentes do ouvido médio, seios paranasais e pulmonares, que podem evoluir para bronquiectasias. Outras manifestações incluem situs inversus totalis e infertilidade masculina. O diagnóstico deve ser suspeitado pelos pediatras em várias situações: recém-nascidos de termo com desconforto respiratório sem causa aparente; neonatos portadores de dextrocardia; lactentes com tosse persistente e/ou infecções otorrinolaringológicas de repetição, excluindo-se as imunodeficiências e a fibrose cística; crianças com asma atípica e as com bronquiectasias sem causa definida. Os testes de triagem diagnóstica são os da sacarina e do óxido nítrico nasal. As avaliações do defeito ultra-estrutural e funcional exigem análise por microscopia eletrônica e da freqüência e formato da onda de batimento ciliar. CONCLUSÕES: A DCP, apesar da baixa prevalência, é pouco diagnosticada pelas dificuldades de estabelecer o diagnóstico definitivo do defeito ciliar devido à complexidade da investigação laboratorial e pela falta de reconhecimento da doença pelos médicos. A suspeita clínica e o diagnóstico precoce são fundamentais para reduzir a morbidade e prevenir o desenvolvimento de complicações.

Pulmonary Radioaerosol Mucociliary Clearance in Diagnosis of Primary Ciliary Dyskinesia

BACKGROUND

Methods relying on nasal ciliary motility for the diagnosis of primary ciliary dyskinesia (PCD) are often hampered by secondary ciliary dyskinesia. A functional test for pulmonary mucociliary clearance, which is not influenced by secondary nasal ciliary defects, would be a valuable tool in a PCD workup.

METHODS

The diagnostic validity and repeatability of a pulmonary radioaerosol mucociliary clearance (PRMC) test for the diagnosis of PCD was assessed in the following three sequentially performed substudies: (1) a preliminary cross-sectional study of PRMC in patients with known PCD; (2) a prospective blinded trial of patients referred for suspicion of PCD; and (3) an implementation study of PRMC as a routine method used in a PCD workup. PRMC was studied after (99m)Tc-albumin colloid aerosol inhalation, and the results were compared to (1) the results of nasal ciliary motility studies, (2) ciliary ultrastructure, and (3) the final clinical diagnosis. The repeatability of PRMC was assessed in 14 patients.

RESULTS

A total of 95 patients, 5 to 74 years of age, were included in the study (57 patients in whom PCD was diagnosed, 26 non-PCD patients, and 12 patients referred for PCD workup without a conclusive workup result). In substudy 1, 14 of 15 patients with known PCD showed impaired PRMC; the results were inconclusive in 1 patient. In substudy 2, among 59 patients referred for PCD workup PRMC test results, compared to nasal ciliary motility, showed a sensitivity of 88% and a specificity of 100%. In substudy 3, among 21 patients referred for PCD investigation who were included in a routine PCD workup after PRMC implementation, 71% of PRMC test results were in alignment with nasal ciliary motility. Repeatability of interpretation was seen in 13 of 14 cases. A conclusive PRMC after only one test was found in 81 of 95 patients (85%).

CONCLUSION

PRMC is a noninvasive functional test for total tracheobronchial mucociliary clearance with a high sensitivity and specificity for PCD, a high rate of conclusive results after only one test and a further ability to separate PCD from focal pulmonary mucociliary defects.

Bronchiectasis and sino-nasal disease: a review

The 'one airway' model for upper and lower respiratory tract disease is a concept gaining increasing momentum in both respiratory medicine and otorhinolaryngology. The specific common aetiology and pathophysiology of concomitant bronchiectasis and sino-nasal disease, such as chronic rhinosinusitis, are discussed here, as well as the clinical manifestations, along with a review of all the relevant literature in the field.

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.

[The respiratory mucociliary system and its exploration in primary ciliary dyskinesia]

BACKGROUND

We analyzed the main characteristic features of the respiratory epithelium mucociliary system and the different tests of ciliary beat and mucociliary transport (mucociliary clearance). This knowledge is necessary for an often interdisciplinary diagnosis and treatment of primary ciliary dyskinesia.

METHODS

Review of the literature and personal experience of the different tests of ciliary structure and function.

RESULTS

This disease is characterized by abnormalities in ciliary structure/function. The genetic mechanisms and the ultrastructural abnormalities that are involved are heterogenous compared to the relative homogeneity of the clinical presentation.

CONCLUSION

The diagnostic criteria are compatible clinical features (chronic upper airway and bronchopulmonary infections, situs inversus...) coupled with tests of ciliary structure and function.

Mucociliary transport using 99mTc-albumin colloid: a reliable screening test for primary ciliary dyskinesia

BACKGROUND

A study was undertaken to assess the reliability of the nasal mucociliary transport test using 99mTc-albumin colloid as a screening test for primary ciliary dyskinesia (PCD) and to compare it with the gold standard nasal biopsy for study of ciliary motility and ultrastructure.

METHODS

During a 4 year period both tests were performed in 55 children referred with persistent or recurrent respiratory tract infections. Their median age was 4 years (range 1 month to 15 years).

RESULTS

The nasal biopsy results were as follows: PCD, n = 8; secondary ciliary dyskinesia (SCD), n = 19; normal, n = 28. The mucociliary transport test was abnormal in 29 patients (all 8 with PCD, 7/19 with SCD, and 14/28 with a normal biopsy). The sensitivity of the mucociliary transport test to diagnose PCD was therefore 100% (8/8) (95% exact confidence limits 63.06 to 100.00); the specificity was only 55% (26/47) (40.95 to 69.89). The negative predictive value was 100% (26/26) (86.77 to 100.00) and the positive predictive value was 28% (8/29) (12.37 to 47.24).

CONCLUSION

Mucociliary transport is a non-invasive screening test that can be performed even in infants. The sensitivity of the test is high but its specificity is low. A normal test result excludes PCD.

La dyskinésie ciliaire primitive

Primary ciliary dyskinesia (PCD) is a genetic disease characterized by abnormalities in ciliary structure/function.

OBJECTIVE

We analyzed the main clinical features and test results of PCD in order to evaluate their usefulness for diagnosis.

PATIENTS AND METHODS

Retrospective study of 35 cases of PCD evaluated by the same team, with nasal brushings in all cases (special light microscopy) and electron microscopy and/or by isotopic mucociliary clearance study in some.

RESULTS

In a cohort of 145 patients with suspected PCD, the diagnosis of PCD was established in 35 cases using a combination of compatible clinical features coupled with the study of nasal brushings: 13 females and 22 males, average age at time of diagnosis 25 years, situs inversus in 12 patients (34%).

CONCLUSION

In the absence of consensus in the literature for diagnosis of PCD, we propose the association of the following diagnostic criteria: upper airway and bronchopulmonary infections beginning often early in the life, more inconstantly situs inversus, familial cases of PCD, consanguinity, infertility and permanent and ubiquitous abnormalities of ciliary structure/function. Nasal brushing with ciliary study (special light microscopy) seems to be an easy and reliable diagnostic criterion. Electron microscopy is necessary for proving ultrastructural abnormalities.