Primary Ciliary Dyskinesia

Compartmentalized mitochondrial ferroptosis converges with optineurin-mediated mitophagy to impact airway epithelial cell phenotypes and asthma outcomes

A stable mitochondrial pool is crucial for healthy cell function and survival. Altered redox biology can adversely affect mitochondria through induction of a variety of cell death and survival pathways, yet the understanding of mitochondria and their dysfunction in primary human cells and in specific disease states, including asthma, is modest. Ferroptosis is traditionally considered an iron dependent, hydroperoxy-phospholipid executed process, which induces cytosolic and mitochondrial damage to drive programmed cell death. However, in this report we identify a lipoxygenase orchestrated, compartmentally-targeted ferroptosis-associated peroxidation process which occurs in a subpopulation of dysfunctional mitochondria, without promoting cell death. Rather, this mitochondrial peroxidation process tightly couples with PTEN-induced kinase (PINK)-1(PINK1)-Parkin-Optineurin mediated mitophagy in an effort to preserve the pool of functional mitochondria and prevent cell death. These combined peroxidation processes lead to altered epithelial cell phenotypes and loss of ciliated cells which associate with worsened asthma severity. Ferroptosis-targeted interventions of this process could preserve healthy mitochondria, reverse cell phenotypic changes and improve disease outcomes.

Regional anesthesia in a patient with primary ciliary dyskinesia: A case report

BACKGROUND

Primary ciliary dyskinesia (PCD) is an inherited autosomal-recessive disorder of impaired mucociliary clearance characterized by chronic respiratory diseases, otolaryngological diseases, central nervous system abnormalities, reproductive system abnormalities, and cardiac function abnormalities. General anesthesia in these patients is associated with a higher incidence of respiratory complications than in patients without the disease.

CASE SUMMARY

A 16-year-old male patient was referred to the emergency room complaining of right ankle pain due to distal tibiofibular fracture. Three years prior, he had been diagnosed with PCD. At that time, he had experienced several episodes of pneumonia, sinusitis, and chronic middle ear infections, for which he underwent surgical interventions. At the current admission, he presented with cough and sputum but no other respiratory symptoms. A chest computed tomography scan revealed centrilobular ground-glass opacities in both lower lobes and a calcified nodule in the left lower lobe. For the surgical procedure and postoperative pain management, combined spinal-epidural anesthesia was employed. The patient's postoperative pain score was measured by the numerical rating scale (NRS). On the day of surgery, his NRS was 5 points. By the second postoperative day, the NRS score had decreased to 2-3 points. The epidural catheter was removed on the fourth day following the operation. The patient was subsequently discharged no respiratory complications.

CONCLUSION

We performed combined spinal-epidural anesthesia in a patient with PCD. The patient experienced no additional respiratory complications and was discharged with a low NRS score for pain.

Genetic Spectrum and Clinical Characteristics of Patients with Primary Ciliary Dyskinesia: a Belgian Single Center Study

PURPOSE

We aimed to examine the correlation between clinical characteristics and the pathogenic gene variants in patients with Primary Ciliary Dyskinesia (PCD).

METHODS

We conducted a retrospective single-center study in patients with PCD followed at the University Hospitals Leuven. We included patients with genetically confirmed PCD and described their genotype, data from ultrastructural ciliary evaluation and clinical characteristics. Genotype/phenotype correlations were studied in patients with the most frequently involved genes.

RESULTS

We enrolled 74 patients with a median age of 25.58 years. The most frequently involved genes were DNAH11 (n = 23) and DNAH5 (n = 19). The most frequent types of pathogenic variants were missense (n = 42) and frameshift variants (n = 36) and most patients had compound heterozygous variants (n = 44). Ciliary ultrastructure (p < 0.001), situs (p = 0.015) and age at diagnosis (median 9.50 vs 4.71 years, p = 0.037) differed between DNAH11 and DNAH5. When correcting for situs this difference in age at diagnosis was no longer significant (p = 0.973). Patients with situs inversus were diagnosed earlier (p = 0.031). Respiratory tract microbiology (p = 0.161), lung function (cross-sectional, p = 0.829 and longitudinal, p = 0.329) and chest CT abnormalities (p = 0.202) were not significantly different between DNAH11 and DNAH5 variants.

CONCLUSION

This study suggests a genotype-phenotype correlation for some of the evaluated clinical characteristics of the two most frequently involved genes in this study, namely DNAH11 and DNAH5.

Two Japanese Pediatric Patients With Primary Ciliary Dyskinesia Caused by Loss-of-Function Variants in the CCNO gene

Primary ciliary dyskinesia (PCD) is a rare congenital disorder caused by pathogenic variants of genes related to cilia. Here, we report two Japanese pediatric patients with PCD caused by pathogenic compound heterozygous variants in the cyclin O (CCNO) gene (Case 1, NM_021147.4:c.[262C>T];[781delC], p.[Gln88Ter];[Leu261fs]; Case 2, c.[262C>T];[c.248_252dupTGCCC], p.[Gln88Ter];[Gly85fs]). The clinical symptoms of the patients were varied. Neither of the patients had situs inversus. Transmission electron microscopy of the respiratory cilia from the nasal mucosa in Case 1 showed a remarkable reduction of cilia and the few residual cilia had central pair defects and microtubular disorganization.

The primary ciliary dyskinesia-related genetic risk score is associated with susceptibility to adult-onset asthma

BACKGROUND

Disturbance of mucociliary clearance is an important factor in the pathogenesis of asthma. We hypothesized that common variants in genes responsible for ciliary function may contribute to the development of asthma with certain phenotypes.

METHODS

Three independent adult Japanese populations (including a total of 1,158 patients with asthma and 2,203 non-asthmatic healthy participants) were studied. First, based on the ClinVar database (https://www.ncbi.nlm.nih.gov/clinvar/), we selected 12 common single-nucleotide polymorphisms (SNPs) with molecular consequences (missense, nonsense, and 3'-untranslated region mutation) in 5 primary ciliary dyskinesia (PCD)-related genes and calculated a PCD-genetic risk score (GRS) as a cumulative effect of these PCD-related genes. Second, we performed a two-step cluster analysis using 3 variables, including PCD-GRS, forced expiratory volume in 1 second (%predicted FEV1), and age of asthma onset.

RESULTS

Compared to adult asthma clusters with an average PCD-GRS, clusters with high and low PCD-GRS had similar overall characteristics: adult-onset, female predominance, preserved lung function, and fewer features of type 2 immunity as determined by IgE reactivity and blood eosinophil counts. The allele frequency of rs1530496, a SNP representing an expression quantitative trait locus (eQTL) of DNAH5 in the lung, showed the largest statistically significant difference between the PCD-GRS-High and PCD-GRS-Low asthma clusters (p = 1.4 x 10-15).

CONCLUSION

Genes associated with PCD, particularly the common SNPs associated with abnormal expression of DNAH5, may have a certain influence on the development of adult-onset asthma, perhaps through impaired mucociliary clearance.

Pulmonary functions, nasal symptoms, and quality of life in patients with primary ciliary dyskinesia (PCD)

BACKGROUND

Several factors may influence quality of life (QOL) for patients with primary ciliary dyskinesia (PCD). We aimed to evaluate the association between pulmonary functions, nasal symptoms and QOL in PCD patients.

METHODS

A prospective single center study. Patients performed spirometry, whole body plethysmography, forced oscillation technique (FOT), lung clearance index (LCI), 6-min walk test (6MWT), and filled two questionnaires: a specific PCD QOL questionnaire (PCD-QOL) and Sino-nasal outcome test (SNOT-22) questionnaire, assessing symptoms of chronic rhinosinusitis and health related QOL.

RESULTS

Twenty-seven patients (56% females), age 19.4 ± 10.5 years were included; their, FEV1 was 74.6 ± 22.7%, and RV/TLC was (157.3 ± 39.3% predicted). Health perception and lower respiratory symptoms domains of PCD-QOL had the lowest score (median [IQR]: 50 [33.3-64.6] and 57.1 [38.9-72.2], respectively). FOT parameters correlated with several PCD-QOL domains. R5 z-score (indicating total airway resistance) and AX z-score (indicating airway reactance) correlated negatively with physical domain (r = -0.598, p = .001, and r = -0.42, p = .03, respectively); R5 z-score also correlated negatively with hearing domain (r = -0.57, p = .002). R5-20 z-score (indicating small airway resistance) correlated negatively with role domain (r = -0.49, p = .03). SNOT-22 score correlated negatively with several PCD-QOL domains (lower respiratory symptoms r = -0.77, p < .001; physical r = -0.72, p < .001; upper respiratory symptoms r = -0.66, p < .001). No correlations were found between spirometry values, LCI, 6MWT, and PCD-QOL.

CONCLUSIONS

FOT suggested small airway dysfunction, and correlated negatively with several PCD-QOL domains. Nasal symptoms had strong negative correlations with PCD-QOL. Larger longitudinal studies will further elucidate factors affecting QOL in PCD.

A gel-coated air-liquid-interface culture system with tunable substrate stiffness matching healthy and diseased lung tissues

Since its invention in the late 1980s, the air-liquid-interface (ALI) culture system has been the standard in vitro model for studying human airway biology and pulmonary diseases. However, in a conventional ALI system, cells are cultured on a porous plastic membrane that is much stiffer than human airway tissues. Here, we develop a gel-ALI culture system by simply coating the plastic membrane with a thin layer of hydrogel with tunable stiffness matching that of healthy and fibrotic airway tissues. We determine the optimum gel thickness that does not impair the transport of nutrients and biomolecules essential to cell growth. We show that the gel-ALI system allows human bronchial epithelial cells (HBECs) to proliferate and differentiate into pseudostratified epithelium. Furthermore, we discover that HBECs migrate significantly faster on hydrogel substrates with stiffness matching that of fibrotic lung tissues, highlighting the importance of mechanical cues in human airway remodeling. The developed gel-ALI system provides a facile approach to studying the effects of mechanical cues in human airway biology and in modeling pulmonary diseases.NEW & NOTEWORTHY In a conventional ALI system, cells are cultured on a plastic membrane that is much stiffer than human airway tissues. We develop a gel-ALI system by coating the plastic membrane with a thin layer of hydrogel with tunable stiffness matching that of healthy and fibrotic airway tissues. We discover that human bronchial epithelial cells migrate significantly faster on hydrogel substrates with pathological stiffness, highlighting the importance of mechanical cues in human airway remodeling.

Absolute quantitation of human wild-type DNAI1 protein in lung tissue using a nanoLC-PRM-MS-based targeted proteomics approach coupled with immunoprecipitation

BACKGROUND

Dynein axonemal intermediate chain 1 protein (DNAI1) plays an essential role in cilia structure and function, while its mutations lead to primary ciliary dyskinesia (PCD). Accurate quantitation of DNAI1 in lung tissue is crucial for comprehensive understanding of its involvement in PCD, as well as for developing the potential PCD therapies. However, the current protein quantitation method is not sensitive enough to detect the endogenous level of DNAI1 in complex biological matrix such as lung tissue.

METHODS

In this study, a quantitative method combining immunoprecipitation with nanoLC-MS/MS was developed to measure the expression level of human wild-type (WT) DNAI1 protein in lung tissue. To our understanding, it is the first immunoprecipitation (IP)-MS based method for absolute quantitation of DNAI1 protein in lung tissue. The DNAI1 quantitation was achieved through constructing a standard curve with recombinant human WT DNAI1 protein spiked into lung tissue matrix.

RESULTS

This method was qualified with high sensitivity and accuracy. The lower limit of quantitation of human DNAI1 was 4 pg/mg tissue. This assay was successfully applied to determine the endogenous level of WT DNAI1 in human lung tissue.

CONCLUSIONS

The results clearly demonstrate that the developed assay can accurately quantitate low-abundance WT DNAI1 protein in human lung tissue with high sensitivity, indicating its high potential use in the drug development for DNAI1 mutation-caused PCD therapy.

A BEAT-PCD consensus statement: a core outcome set for pulmonary disease interventions in primary ciliary dyskinesia

Background

Consistent use of reliable and clinically appropriate outcome measures is a priority for clinical trials, with clear definitions to allow comparability. We aimed to develop a core outcome set (COS) for pulmonary disease interventions in primary ciliary dyskinesia (PCD).

Methods

A multidisciplinary international PCD expert panel was set up. A list of outcomes was created based on published literature. Using a modified three-round e-Delphi technique, the panel was asked to decide on relevant end-points related to pulmonary disease interventions and how they should be reported. First, inclusion of an outcome in the COS was determined. Second, the minimum information that should be reported per outcome. The third round finalised statements. Consensus was defined as ≥80% agreement among experts.

Results

During the first round, experts reached consensus on four out of 24 outcomes to be included in the COS. Five additional outcomes were discussed in subsequent rounds for their use in different subsettings. Consensus on standardised methods of reporting for the COS was reached. Spirometry, health-related quality-of-life scores, microbiology and exacerbations were included in the final COS.

Conclusion

This expert consensus resulted in a COS for clinical trials on pulmonary health among people with PCD.

The First Case of a Homozygous CCNO NM 021147.4 Mutation Associated With Primary Ciliary Dyskinesia in Two Indian Siblings

Primary ciliary dyskinesia (PCD) is a heterogeneous autosomal recessive disease marked by organ lateralization in 50% of patients, chronic sinopulmonary disease, infertility in men, and neonatal respiratory distress. Respiratory control cells contain CCNO in their apical cytoplasm, which is necessary for the development of multiciliate cells, basal body amplification, and migration. Reduced generation of multiple motile cilia, a rare form of PCD, has been linked to CCNO gene abnormalities. Individuals with CCNO mutations have been reported to suffer from severe lower respiratory infections that cause progressive impairment of lung function. For the first time, we describe the CCNO NM 021147.4 (c.258 262dup.p, Gln88argfs*8 Homozygous) gene mutation in an Indian consanguineous family that resulted in severe PCD.

Cilia-related diseases

More and more attention is paid to diseases such as internal transfer and brain malformation which are caused by the abnormal morphogenesis of cilia. These cilia-related diseases are divided into two categories: ciliopathy resulting from defects of primary cilia and primary ciliary dyskinesia (PCD) caused by functional dysregulation of motile cilia. Cilia are widely distributed, and their related diseases can cover many human organs and tissues. Recent studies prove that primary cilia play a key role in maintaining homeostasis in the cardiovascular system. However, molecular mechanisms of cilia-related diseases remain elusive. Here, we reviewed recent research progresses on characteristics, molecular mechanisms and treatment methods of ciliopathy and PCD. Our review is beneficial to the further research on the pathogenesis and treatment strategies of cilia-related diseases.

Lack of CFAP54 causes primary ciliary dyskinesia in a mouse model and human patients

Primary ciliary dyskinesia (PCD) is a highly heterogeneous recessive inherited disorder. FAP54, the homolog of CFAP54 in Chlamydomonas reinhardtii, was previously demonstrated as the C1d projection of the central microtubule apparatus of flagella. A Cfap54 knockout mouse model was then reported to have PCD-relevant phenotypes. Through whole-exome sequencing, compound heterozygous variants c.2649_2657delinC (p. E883Dfs*47) and c.7312_7313insCGCAGGCTGAATTCTTGG (p. T2438delinsTQAEFLA) in a new suspected PCD-relevant gene, CFAP54, were identified in an individual with PCD. Two missense variants, c.4112A>C (p. E1371A) and c.6559C>T (p. P2187S), in CFAP54 were detected in another unrelated patient. In this study, a minigene assay was conducted on the frameshift mutation showing a reduction in mRNA expression. In addition, a CFAP54 in-frame variant knock-in mouse model was established, which recapitulated the typical symptoms of PCD, including hydrocephalus, infertility, and mucus accumulation in nasal sinuses. Correspondingly, two missense variants were deleterious, with a dramatic reduction in mRNA abundance from bronchial tissue and sperm. The identification of PCD-causing variants of CFAP54 in two unrelated patients with PCD for the first time provides strong supportive evidence that CFAP54 is a new PCD-causing gene. This study further helps expand the disease-associated gene spectrum and improve genetic testing for PCD diagnosis in the future.

Cardiac Laterality: Surgical Results of Right Atrial Isomerism

Right atrial isomerism (RAI) is a complex entity with varying diagnostic and treatment outcomes due to its rarity. Treatment options range from palliative to corrective surgeries, resulting in heterogeneous outcomes. The aim of this study was to analyze the results obtained after cardiac surgery in patients with RAI. A retrospective study was conducted, including patients diagnosed with RAI who underwent cardiac surgery. Their follow-up was from 1 January 2010 to 31 March 2020. Demographic characteristics and perioperative conditions were described. Thirty-eight patients were included, the median age was 4 years (IQR 2-9.2) and 57.9% were men. The main diagnoses were atrioventricular canal (63.2%) and pulmonary stenosis (55.3%). The most common surgical procedures were modified Blalock-Taussig shunt (65.8%) and total cavopulmonary connection with an extracardiac conduit fenestrated without cardiopulmonary bypass (15.9%). We did not find any factors associated with negative outcomes in these patients. The overall survival was 86.8%, with a better outcome in those who did not require reintubation (log rank, p < 0.01). The survival of RAI was similar to other centers. Individuals with RAI should be evaluated rigorously to determine an adequate repair strategy, considering high morbidity and mortality.

Results and perinatal outcomes from 189 ICSI cycles of couples with asthenozoospermic men and flagellar defects assessed by transmission electron microscopy

RESEARCH QUESTION

Do patients presenting with flagella ultrastructural defects as assessed by electron microscopy, and defined within three phenotypes (dysplasia of the fibrous sheath [DFS], primary flagellar dyskinesia [PFD] and non-specific flagellar abnormalities [NSFA]), have decreased chances of success in intracytoplasmic sperm injection (ICSI) or adverse obstetric and neonatal outcomes?

DESIGN

Retrospective analysis of 189 ICSI cycles from 80 men with spermatozoa flagellum ultrastructural defects (DFS [n = 16]; PFD [n = 14]; NSFA [n = 50] compared with a control group (n = 97). Cycles were cumulatively analysed. All fresh and frozen embryo transfers resulting from each ICSI attempt were included. The effect of transmission electron microscopy (TEM) phenotype on the main ICSI outcomes was assessed by a multivariate logistic regression combined with a generalized linear mixed model to account for the non-independence of the observations.

RESULTS

No predictive value of TEM phenotype was found on the main outcomes of ICSI, namely fertilization rates, pregnancy and delivery rates, and cumulative pregnancy and delivery rates. Cumulative pregnancy rates ranged from 29.0-43.3% in the different TEM phenotype subgroups compared with 36.8% in the control group. Cumulative live birth rates ranged from 24.6-36.7% compared with 31.4% in the control group. No increase was found in miscarriages, preterm births, low birth weights or birth abnormalities.

CONCLUSIONS

Data on the cumulative chances of success in ICSI of patients with ultrastructural flagellar defects, a rare cause of male infertility often associated with an underlying genetic cause, are reassuring, as are obstetrical and neonatal outcomes in this population.

Muco-Obstructive Lung Disease: A Systematic Review

Muco-obstructive lung disease is a new classification under the diseases of respiratory tract. A lot of discussion is still going on regarding this new group of diseases. It is characterised by obstruction of the respiratory tract with a thick mucin layer. Usually in normal individuals, the mucus is swept out of the respiratory system while coughing in the form of sputum or phlegm, but if the consistency of the mucus is thick, or the amount is heavy or there is a certain defect in the ciliary function of the respiratory tract, the mucus is not cleared and it gets accumulated in the lungs alveoli, therefore blocking it. The mucus trapped in the distal airways cannot be cleared by coughing therefore forming a layer in the alveoli and bronchioles. Long-standing condition causes inflammation and infection. This new group of diseases specifically includes chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), primary ciliary dyskinesia (PCD) and non-cystic fibrosis bronchiectasis (NCFB). Asthma, although an obstructive disease of the lung, is not particularly included under muco-obstructive lung disease. The major symptoms with which these diseases present are sputum production, chronic cough and acute exacerbations of the condition. The mucus adheres to the lung parenchyma causing airway obstruction and hyperinflation. In this article, we will see how muco-obstructive lung diseases affect the normal physiology of the respiratory system and how is it different from other obstructive and restrictive lung diseases. We will individually look into all the four conditions that come under the category of muco-obstructive lung diseases.

Primary ciliary dyskinesia diagnosis and management and its implications in America: a mini review

Introduction

Primary ciliary dyskinesia (PCD) is a rare genetic disorder that can result in significant morbidity and mortality if left untreated. Clinical manifestations of PCD include recurrent respiratory infections, laterality defects, and infertility, all of which arise from impaired or absent ciliary motility. Diagnostic approaches for PCD may include high-speed video microscopy, measurement of nasal nitric oxide levels, and genetic testing; however, no single definitive diagnostic test exists. The present study aims to highlight the lack of standardized diagnostic and treatment guidelines for PCD in Latin America (Central and South America, and the Caribbean). To this effect, we compared North American and European recommendations for the diagnosis and management of PCD and found that certain diagnostic tools and treatment options mentioned in these guidelines are not readily accessible in many Latin American countries.

Methods & Results

This review gathers disease information in North America, Europe, and Latin America organizing guideline results into tables for clarity and potential interventions. Management information for Latin America is inferred from case reports, as most findings are from North American recommendations and studies on PubMed, Google Scholar, and Scopus. Treatment and management information is based on North American and European standards.Among 5,774 publications reviewed, only 15 articles met the inclusion criteria (focused on PCD management, peer-reviewed, and located in America). No clinical guideline for PCD in Latin America was found, but recommendations on respiratory management from Colombia and Chile were discovered. The lack of guidelines in Latin America may originate from limited resources and research on the disease in those countries.

Discussion

PCD lacks documentation, research, and recommendations regarding its prevalence in Latin America, likely due to unfavorable economic conditions. This disadvantage results in limited access to diagnostic tests available in North America and Europe. The PICADAR score, discussed in this review, can be used in low-income nations as a screening tool for the disorder.

Biallelic mutations in CFAP54 cause male infertility with severe MMAF and NOA

BACKGROUND

Spermatogenic impairments can lead to male infertility by different pathological conditions, such as multiple morphological abnormalities of the sperm flagella (MMAF) and non-obstructive azoospermia (NOA). Genetic factors are involved in impaired spermatogenesis.

METHODS AND RESULTS

Here, we performed genetic analyses through whole-exome sequencing in a cohort of 334 Han Chinese probands with severe MMAF or NOA. Biallelic variants of CFAP54 were identified in three unrelated men, including one homozygous frameshift variant (c.3317del, p.Phe1106Serfs*19) and two compound heterozygous variants (c.878G>A, p.Arg293His; c.955C>T, p.Arg319Cys and c.4885C>T, p.Arg1629Cys; c.937G>A, p.Gly313Arg). All of the identified variants were absent or extremely rare in the public human genome databases and predicted to be damaging by bioinformatic tools. The men harbouring CFAP54 mutations exhibited abnormal sperm morphology, reduced sperm concentration and motility in ejaculated semen. Significant axoneme disorganisation and other ultrastructure abnormities were also detected inside the sperm cells from men harbouring CFAP54 mutations. Furthermore, immunofluorescence assays showed remarkably reduced staining of four flagellar assembly-associated proteins (IFT20, IFT52, IFT122 and SPEF2) in the spermatozoa of CFAP54-deficient men. Notably, favourable clinical pregnancy outcomes were achieved with sperm from men carrying CFAP54 mutations after intracytoplasmic sperm injection treatment.

CONCLUSION

Our genetic analyses and experimental observations revealed that biallelic deleterious mutations of CFAP54 can induce severe MMAF and NOA in humans.

In Vitro Effect of Combined Hypertonic Saline and Salbutamol on Ciliary Beating Frequency and Mucociliary Transport in Human Nasal Epithelial Cells of Healthy Volunteers and Patients with Cystic Fibrosis

Background: Inhalation of hypertonic saline (HS) is standard of care in patients with cystic fibrosis (CF). However, it is unclear if adding salbutamol has-besides bronchodilation-further benefits, for example, on the mucociliary clearance. We assessed this in vitro by measuring the ciliary beating frequency (CBF) and the mucociliary transport rate (MCT) in nasal epithelial cells (NECs) of healthy volunteers and patients with CF. Aims: To investigate the effect of HS, salbutamol, and its combination on (muco)ciliary activity of NECs in vitro, and to assess potential differences between healthy controls and patients with CF. Methods: NECs obtained from 10 healthy volunteers and 5 patients with CF were differentiated at the air-liquid interface and aerosolized with 0.9% isotonic saline ([IS] control), 6% HS, 0.06% salbutamol, or combined HS and salbutamol. CBF and MCT were monitored over 48-72 hours. Results: In NECs of healthy controls, the absolute CBF increase was comparable for all substances, but CBF dynamics were different: HS increased CBF slowly and its effect lasted for an extended period, salbutamol and IS increased CBF rapidly and the effect subsided similarly fast, and HS and salbutamol resulted in a rapid and long-lasting CBF increase. Results for CF cells were comparable, but less pronounced. Similar to CBF, MCT increased after the application of all the tested substances. Conclusion: CBF and MCT of NECs of healthy participants and CBF of patients with CF increased upon treatment with aerosolized IS, HS, salbutamol, or HS and salbutamol, showing a relevant effect for all tested substances. The difference in the CBF dynamics can be explained by the fact that the properties of the mucus are changed differently by different saline concentrations.

Mucolytic treatment of chronic rhinosinusitis in a murine model of primary ciliary dyskinesia

Background: Genetic defects in motile cilia cause primary ciliary dyskinesia (PCD), a rare disease with no specific therapeutics. Individuals with PCD often have impaired fertility and laterality defects and universally suffer from upper and lower airway diseases. Chronic rhinosinusitis is a universal feature of PCD, and mucus accumulation and subsequent infections of the sinonasal cavity cause significant morbidity in individuals with PCD. Despite this, there are no approved treatments that specifically target mucus. Objective: The goals of this study were to determine whether computed tomography (CT) imaging could be used to quantify mucus accumulation and whether the use of a mucolytic agent to reduce disulfide cross-links present in mucins would improve the effectiveness of nasal lavage at removing mucus in a murine model of PCD. Methods: Adult mice with a deletion of the axonemal dynein Dnaic1 were imaged using CT scanning to characterize mucus accumulation. The animals were then treated by nasal lavage with saline, with/without the disulfide-reducing agent tris(2-carboxyethyl)phosphine. Post-treatment CT scans were used to quantify improvement in the sinonasal cavity. Results: Mucus accumulation in the nasal cavity was readily quantified by CT. Compared to sham-treated control animals, nasal lavage with/without a mucolytic agent resulted in a significant reduction of accumulated mucus (p < 0.01). Treatment with the mucolytic agent showed a greater reduction of accumulated mucus than treatment with saline alone. Conclusion: The results suggest that inclusion of a mucolytic agent may increase the effectiveness of nasal lavage at reducing mucus burden in PCD.

Risk factors for the deterioration of pulmonary function in primary ciliary dyskinesia

BACKGROUND

PCD is a genetic disease leading to a decline in pulmonary function. There is only little knowledge of factors determining the long-term pulmonary outcome. Especially adherence has not been addressed yet although being an independent risk factor for an increased loss of lung capacity in other chronic respiratory diseases.

OBJECTIVE

Assessing the impact of bacterial airway colonization and adherence on long-term lung function in patients with PCD.

METHODS

Data on colonization and lung function parameters like forced expiratory volume in the first second (FEV1, Z-score) and lung clearance index (LCI2,5% ) were collected for 7.01 ± 2.2 years (893 quarters) in 44 PCD patients. Adherence was classified as good, moderate or poor. The impact of both adherence and colonization was assessed for the long-term course of FEV1, the association of colonization with lung function also quarterly.

STATISTICS

Kruskall-Wallis test, T test, ANOVA, linear regression, linear mixed model.

RESULTS

Chronic colonization did not show any impact on the for long-term course of FEV1 , but adherence was a significant factor: patients with good adherence showed better FEV1 at the end of the observation period than children with poor adherence (-0.15 ± 0.88 vs. -2.63 ± 1.79, p < 0.01).

CONCLUSION

Adherence has not yet been investigated for PCD. However, we found it to be a major significant factor affecting long-term FEV1 in PCD. Thus, it should be taken into consideration in the treatment protocols for PCD.

Case Report: A Novel Homozygous Mutation of Cyclin O Gene Mutation in Primary Ciliary Dyskinesia with Short Stature

Background

Primary ciliary dyskinesia (PCD) is a group of autosomal recessive genetic diseases caused by abnormal ciliary ultrastructure and/or function, resulting in reduced ciliary clearance function or other dysfunctions. PCD is one of the causes of recurrent respiratory tract infections in children. At present, there is no gold standard for diagnosis. In patients clinically suspected with PCD, a variety of examination methods are available to assist in diagnosis, such as high-speed video microscopic imaging to analyze ciliary movement patterns, transmission electron microscopy to observe ciliary ultrastructure, genetic testing, and detection of nitric oxide content in nasal expiratory air.

Case Description

We present a case summary of the clinical data and treatment process of a child with PCD and short stature induced by Novel exon 1 of CCNO mutation (NM-021147.5) at c.323del, and the proband father and mother were heterozygous mutators, who was diagnosed and treated in the Pediatric Healthcare Department of our hospital. We treated the child with recombinant human growth hormone to increase the height, and the patient was also advised to improve nutrition, prevent and control infections, and encouraged sputum expectoration. We also recommended regular follow-up visits to the outpatient department, and to seek other symptomatic and supportive treatments as necessary.

Conclusion

The height and nutritional status of the child improved after treatment. We also reviewed relevant literature to help clinicians improve their understanding of this disease.

Revisiting Host-Pathogen Interactions in Cystic Fibrosis Lungs in the Era of CFTR Modulators

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators, a new series of therapeutics that correct and potentiate some classes of mutations of the CFTR, have provided a great therapeutic advantage to people with cystic fibrosis (pwCF). The main hindrances of the present CFTR modulators are related to their limitations in reducing chronic lung bacterial infection and inflammation, the main causes of pulmonary tissue damage and progressive respiratory insufficiency, particularly in adults with CF. Here, the most debated issues of the pulmonary bacterial infection and inflammatory processes in pwCF are revisited. Special attention is given to the mechanisms favoring the bacterial infection of pwCF, the progressive adaptation of Pseudomonas aeruginosa and its interplay with Staphylococcus aureus, the cross-talk among bacteria, the bronchial epithelial cells and the phagocytes of the host immune defenses. The most recent findings of the effect of CFTR modulators on bacterial infection and the inflammatory process are also presented to provide critical hints towards the identification of relevant therapeutic targets to overcome the respiratory pathology of pwCF.

Pathophysiology of pulmonary nontuberculous mycobacterial (NTM) disease

In recent years, the incidence and prevalence of pulmonary nontuberculous mycobacterial (NTM) disease have increased worldwide. Although the reasons for this increase are unclear, dealing with this disease is essential. Pulmonary NTM disease is a chronic pulmonary infection caused by NTM bacteria, which are ubiquitous in various environments. In Japan, Mycobacterium avium-intracellulare complex (MAC) accounts for approximately 90% of the causative organisms of pulmonary NTM disease, which is also called pulmonary MAC disease or pulmonary MAI disease. It is important to elucidate the pathophysiology of this disease, which occurs frequently in postmenopausal women despite the absence of obvious immunodeficiency. The pathophysiology of this disease has not been fully elucidated; however, it can largely be divided into bacterial (environmental) and host-side problems. The host factors can be further divided into immune and airway problems. The authors suggest that the triangular relationship between bacteria, immunity, and the airway is important in the pathophysiology of this disease. The latest findings on the pathophysiology of pulmonary NTM disease are reviewed.

Use of dornase alfa in pediatric patients without cystic fibrosis

OBJECTIVES

Literature regarding clinical benefits of dornase alfa (DNase) in pediatric patients without cystic fibrosis is lacking. In December 2020, the study institution implemented restrictions to limit DNase use in this patient population. The primary objective was adherence to DNase ordering restrictions. Secondary objectives included length of stay, respiratory function, and use of inhaled mucolytic agents.

METHODS

This single-center retrospective chart review included patients less than 18 years of age who received DNase one year prior to through one year after order restriction implementation. Data collected included patient demographics and respiratory clinical parameters. Dosing regimens for DNase, n-acetylcysteine, and hypertonic saline were collected, as well as changes in length of stay (LOS) and adherence to ordering restrictions.

RESULTS

Of 101 total DNase orders, 45 were placed after implementation of ordering restrictions and 16 (36%) met all ordering criteria. Hospital and intensive care unit (ICU) LOS after implementation of restrictions were not significantly different (p = 0.767 and p = 0.219, respectively). There was no significant change in patients' mean oxygenation index (p = 0.252) or FiO2% (p = 0.113) 24 hours after DA administration.

CONCLUSION

Respiratory function did not significantly change after DNase administration. Implementing restrictions on DNase did not impact intensive care unit or hospital LOS. Adherence to DNase ordering restrictions could be improved.

Anesthetic Management of Patients With Kartagener Syndrome: A Systematic Review of 99 Cases

KARTAGENER SYNDROME (KS) is characterized by the triad of chronic sinusitis, bronchiectasis, and situs inversus. The mirrored anatomy and respiratory infections in patients with KS patients pose great challenges for anesthetic management. The aim of this review is to summarize published cases with the hope of helping anesthesiologists perform anesthesia in patients with KS more safely. A comprehensive literature search for all cases of anesthetic management of KS patients was performed in Pubmed, EMBASE, CNKI, and Wanfang Database. The extracted data included age, sex, type of surgery, preoperative treatment, type of anesthesia, anesthetic agents, airway management, central venous catheterization, transesophageal echocardiogram, reversal of neuromuscular blockade, adverse events during the surgery, and postoperative complications. The study authors included 82 single-case reports, 3 case series, and 1 case cohort, with a total number of 99 patients. The most common surgical procedures were thoracic surgery (51.5%), which was followed by ear, nose, and throat surgery (16.5%), and general surgery (14.5%). The preoperative treatment of the patients was reported in only 20 patients, and included antibiotics, bronchodilators, steroids, chest physiotherapy, and postural drainage. General anesthesia was performed for 85.4% of the surgeries, and regional anesthesia was performed in 14.6% of the cases. For nonthoracic surgery, an endotracheal tube was the most commonly used airway device. For thoracic surgery, a double-lumen tube was the most commonly used airway device. The intraoperative process was uneventful in most patients, and most patients recovered smoothly in the postoperative course.

The EZ-Blocker® for one-lung ventilation in a patient with Kartagener syndrome and tracheal bronchus -a case report

BACKGROUND

The tracheal bronchus in Kartagener syndrome is a rare case that may cause difficulty in one-lung ventilation (OLV). Here we reported a case of successful OLV using bronchial blocker in a patient with tracheal bronchus and Kartagener syndrome (KS).

CASE

A 66-year-old female patient with Kartagener syndrome was admitted for left-side diaphragmatic plication. The patient's preoperative computed tomography image showed a tracheal bronchus of the apical segment in the right upper lobe. The patient received epidural analgesia and general anesthesia through total intravenous anesthesia. An EZ-Blocker® (Teleflex Life Sciences Ltd., Ireland) was used to perform OLV.

CONCLUSIONS

OLV through an EZ-Blocker® can be successfully performed in tracheal bronchus patients with Kartagener syndrome without side effects.

Towards an atomic model of a beating ciliary axoneme

The axoneme of motile cilia and eukaryotic flagella is an ordered assembly of hundreds of proteins that powers the locomotion of single cells and generates flow of liquid and particles across certain mammalian tissues. The symmetric and organized structure of the axoneme has invited structural biologists to unravel its intricate architecture at different scales. In the last few years, single-particle cryo-electron microscopy provided high-resolution structures of axonemal complexes that comprise dozens of proteins and are key to cilia function. This review summarizes unique structural features of the axoneme and the framework they provide to understand cilia assembly, the mechanism of ciliary beating, and clinical conditions associated with impaired cilia motility.

Cilia Ultrastructure Associated with Primary Ciliary Dyskinesia in Omani Patients

Objectives

Primary ciliary dyskinesia (PCD) is a disorder affecting the structure and function of the motile cilia of the respiratory system. Transmission electron microscopy is one method that can be used to examine ciliary ultrastructure in airway biopsies. Although the role of ultrastructural findings in PCD has been described in the literature, this role has not been well-studied in the Middle East or, specifically, Oman. This study aimed to describe ultrastructural features in Omani patients with high suspicion of PCD.

Methods

This retrospective cross-sectional study included 129 adequate airway biopsies obtained from Omani patients attending pulmonary clinics at Sultan Qaboos University Hospital and the Royal Hospital, Muscat, Oman, from 2010 to 2020 who were suspected of having PCD.

Results

Ciliary ultrastructural abnormalities in the current study population were outer dynein arm (ODA) associated with inner dynein arm (IDA) defects (8%), microtubular disorganisation associated with IDA defect (5%) and isolated ODA defect (2%). Most of the biopsies showed normal ultrastructure (82%).

Conclusion

In Omani patients suspected to have PCD, normal ultrastructure was the most common feature.

Homozygous variants in AKAP3 induce asthenoteratozoospermia and male infertility

BACKGROUND

As a common type of asthenoteratozoospermia, multiple morphological abnormalities of the sperm flagella (MMAF) can cause male infertility. Previous studies have revealed genetic factors as a major cause of MMAF. The known MMAF-associated genes are involved in the mitochondrial sheath, outer dense fibre or axoneme of the sperm flagella. These findings indicate the genetic heterogeneity of MMAF.

METHODS AND RESULTS

Here, we conducted genetic analyses using whole-exome sequencing in a cohort of 150 Han Chinese men with asthenoteratozoospermia. Homozygous deleterious variants of AKAP3 (A-kinase anchoring protein 3) were identified in two MMAF-affected men from unrelated families. One AKAP3 variant was a frameshift (c.2286_2287del, p.His762Glnfs*22) and the other variant was a missense mutation (c.44G>A, p.Cys15Tyr), which was predicted to be damaging by multiple bioinformatics tools. Further western blotting and immunofluorescence assays revealed the absence of AKAP3 in the spermatozoa from the man harbouring the homozygous frameshift variant, whereas the expression of AKAP3 was markedly reduced in the spermatozoa of the man with the AKAP3 missense variant p.Cys15Tyr. Notably, the clinical outcomes after intracytoplasmic sperm injection (ICSI) were divergent between these two cases, suggesting a possibility of AKAP3 dosage-dependent prognosis of ICSI treatment.

CONCLUSIONS

Our study revealed AKAP3 as a novel gene involved in human asthenoteratozoospermia.

DNAH11 and a Novel Genetic Variant Associated with Situs Inversus: A Case Report and Review of the Literature

Background

Primary ciliary dyskinesia (PCD), also known as the immotile-cilia syndrome, is a clinically and genetically heterogeneous syndrome. Improper function of the cilia causes impaired mucociliary clearance. Neonatal respiratory distress, rhinosinusitis, recurrent chest infections, wet cough, and otitis media are respiratory presentations of this disease. It could also manifest as infertility in males as well as laterality defects in both sexes, such as situs abnormalities (Kartagener syndrome). During the past decade, numerous pathogenic variants in 40 genes have been identified as the causatives of primary ciliary dyskinesia. DNAH11 (dynein axonemal heavy chain 11) is a gene that is responsible for the production of cilia's protein and encodes the outer dynein arm. Dynein heavy chains are motor proteins of the outer dynein arms and play an essential role in ciliary motility. Case Presentation. A 3-year-old boy, the offspring of consanguineous parents, was referred to the pediatric clinical immunology outpatient department with a history of recurrent respiratory tract infections and periodic fever. Furthermore, on medical examination, situs inversus was recognized. His lab results revealed elevated levels of erythrocyte sedimentation rate (ESR) and C reactive protein (CRP). Serum IgG, IgM, and IgA levels were normal, while IgE levels were elevated. Whole exome sequencing (WES) was performed for the patient. WES demonstrated a novel homozygous nonsense variant in DNAH11 (c.5247G > A; p. Trp1749Ter).

Conclusion

We reported a novel homozygous nonsense variant in DNAH11 in a 3-year-old boy with primary ciliary dyskinesia. Biallelic pathogenic variants in one of the many coding genes involved in the process of ciliogenesis lead to PCD.

Homozygous mutation in DNAAF4 causes primary ciliary dyskinesia in a Chinese family

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disorder that affects the structure and function of motile cilia, leading to classic clinical phenotypes, such as situs inversus, chronic sinusitis, bronchiectasis, repeated pneumonia and infertility. In this study, we diagnosed a female patient with PCD who was born in a consanguineous family through classic clinical manifestations, transmission electron microscopy and immunofluorescence staining. A novel DNAAF4 variant NM_130810: c.1118G>A (p. G373E) was filtered through Whole-exome sequencing. Subsequently, we explored the effect of the mutation on DNAAF4 protein from three aspects: protein expression, stability and interaction with downstream DNAAF2 protein through a series of experiments, such as transfection of plasmids and Co-immunoprecipitation. Finally, we confirmed that the mutation of DNAAF4 lead to PCD by reducing the stability of DNAAF4 protein, but the expression and function of DNAAF4 protein were not affected.

LOF variants identifying candidate genes of laterality defects patients with congenital heart disease

Defects in laterality pattern can result in abnormal positioning of the internal organs during the early stages of embryogenesis, as manifested in heterotaxy syndrome and situs inversus, while laterality defects account for 3~7% of all congenital heart defects (CHDs). However, the pathogenic mechanism underlying most laterality defects remains unknown. In this study, we recruited 70 laterality defect patients with CHDs to identify candidate disease genes by exome sequencing. We then evaluated rare, loss-of-function (LOF) variants, identifying candidates by referring to previous literature. We chose TRIP11, DNHD1, CFAP74, and EGR4 as candidates from 776 LOF variants that met the initial screening criteria. After the variants-to-gene mapping, we performed function research on these candidate genes. The expression patterns and functions of these four candidate genes were studied by whole-mount in situ hybridization, gene knockdown, and gene rescue methods in zebrafish models. Among the four genes, trip11, dnhd1, and cfap74 morphant zebrafish displayed abnormalities in both cardiac looping and expression patterns of early signaling molecules, suggesting that these genes play important roles in the establishment of laterality patterns. Furthermore, we performed immunostaining and high-speed cilia video microscopy to investigate Kupffer's vesicle organogenesis and ciliogenesis of morphant zebrafish. Impairments of Kupffer's vesicle organogenesis or ciliogenesis were found in trip11, dnhd1, and cfap74 morphant zebrafish, which revealed the possible pathogenic mechanism of their LOF variants in laterality defects. These results highlight the importance of rare, LOF variants in identifying disease-related genes and identifying new roles for TRIP11, DNHD1, and CFAP74 in left-right patterning. Additionally, these findings are consistent with the complex genetics of laterality defects.

Physiology and pathophysiology of human airway mucus

The mucus clearance system is the dominant mechanical host defense system of the human lung. Mucus is cleared from the lung by cilia and airflow, including both two-phase gas-liquid pumping and cough-dependent mechanisms, and mucus transport rates are heavily dependent on mucus concentration. Importantly, mucus transport rates are accurately predicted by the gel-on-brush model of the mucociliary apparatus from the relative osmotic moduli of the mucus and periciliary-glycocalyceal (PCL-G) layers. The fluid available to hydrate mucus is generated by transepithelial fluid transport. Feedback interactions between mucus concentrations and cilia beating, via purinergic signaling, coordinate Na+ absorptive vs Cl- secretory rates to maintain mucus hydration in health. In disease, mucus becomes hyperconcentrated (dehydrated). Multiple mechanisms derange the ion transport pathways that normally hydrate mucus in muco-obstructive lung diseases, e.g., cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), non-CF bronchiectasis (NCFB), and primary ciliary dyskinesia (PCD). A key step in muco-obstructive disease pathogenesis is the osmotic compression of the mucus layer onto the airway surface with the formation of adherent mucus plaques and plugs, particularly in distal airways. Mucus plaques create locally hypoxic conditions and produce airflow obstruction, inflammation, infection, and, ultimately, airway wall damage. Therapies to clear adherent mucus with hydrating and mucolytic agents are rational, and strategies to develop these agents are reviewed.

Clinical and genetic spectrum of primary ciliary dyskinesia in Chinese patients: a systematic review

Background

Primary ciliary dyskinesia (PCD) represents a highly heterogenous disorder with extensive clinical and genetic patterns among populations of different geographic location and ethnic origin. However, data about Chinese patients are limited. We aimed to summarize the clinical and genetic spectrum of Chinese PCD patients based on all available literatures.

Methods

We searched Embase, Pubmed, Web of Science and Chinese databases including CNKI, SinoMed and Wanfang from 1981 to 2021, to identify articles reporting patients with PCD in China, which had included information about transmission electron microscopy and/or genetic testing.

Results

A total of 244 Chinese PCD patients in 52 articles were included. Of these patients, the mean age was 13.1 years, and 55 patients (22.5%) were diagnosed with PCD after 18 years old. Compared with patients diagnosed with PCD in childhood or infancy, patients diagnosed with PCD in adulthood had a higher prevalence of chronic wet cough, sinusitis, Pseudomonas aeruginosa (PA) isolation and radiological bronchiectasis as well as worse lung function. 25 PCD-related genes were identified in 142 patients, and DNAH5, DNAH11, CCDC39 and CCDC40 were the most frequently detected mutations. More than half of genetic variants were loss-of-function mutations, and the majority of these variants were seen only once. Correlations between PCD phenotype, genotype and ciliary ultrastructure were also evidenced.

Conclusions

Diagnostic delay and under-recognition of PCD remain a big issue in China, which contributes to progressive lung disease and PA infection indicating worse outcome. Specialist equipment and expertise are urgently required to facilitate the early diagnosis and treatment of PCD.

Trial registry

PROSPERO; No.: CRD42021257804; URL:www.crd.york.ac.uk/prospero/

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02427-1.

Case Report: DNAAF4 Variants Cause Primary Ciliary Dyskinesia and Infertility in Two Han Chinese Families

Background: Primary ciliary dyskinesia (PCD) is a rare genetic disorder, predominantly autosomal recessive. The dynein axonemal assembly factor 4 (DNAAF4) is mainly involved in the preassembly of multisubunit dynein protein, which is fundamental to the proper functioning of cilia and flagella. There are few reports of PCD-related pathogenic variants of DNAAF4, and almost no DNAAF4-related articles focused on sperm phenotype. Moreover, the association between DNAAF4 and scoliosis has never been reported, to the best of our knowledge.

Materials and Methods: We recruited two patients with a clinical diagnosis of PCD. One came from a consanguineous and another from a non-consanguineous family. Clinical data, laboratory test results, and imaging data were analyzed. Through whole exome sequencing, immunofluorescence, electron microscopy, high-speed video microscopy analysis, and hematoxylin–eosin (HE) staining, we identified the disease-associated variants and validated the pathogenicity.

Results: Proband 1 (P1, F1: II-1), a 19-year-old man, comes from a non-consanguineous family-I, and proband 2 (P2, F2: II-1), a 37-year-old woman, comes from a consanguineous family-II. Both had sinusitis, bronchiectasis, situs inversus, and scoliosis. P1 also had asthenoteratozoospermia, and P2 had an immature uterus. Two homozygous pathogenic variants in DNAAF4 (NM_130810.4), c.988C &gt; T, p.(Arg330Trp), and DNAAF4 (NM_130810.4), c.733 C &gt; T, p.(Arg245*), were identified through whole exome sequencing. High-speed microscopy analysis showed that most of the cilia were static in P1, with complete static of the respiratory cilia in P2. Immunofluorescence showed that the outer dynein arms (ODA) and inner dynein arms (IDA) were absent in the respiratory cilia of both probands, as well as in the sperm flagellum of P1. Transmission electron microscopy revealed the absence of ODA and IDA of respiratory cilia of P2, and HE staining showed irregular, short, absent, coiled, and bent flagella.

Conclusion: Our study identified a novel variant c.733C &gt; T, which expanded the spectrum of DNAAF4 variants. Furthermore, we linked DNAAF4 to asthenoteratozoospermia and likely scoliosis in patients with PCD. This study will contribute to a better understanding of PCD.

Genetic and Clinical Features of Heterotaxy in a Prenatal Cohort

Objectives: Some genetic causes of heterotaxy have been identified in a small number of heterotaxy familial cases or animal models. However, knowledge on the genetic causes of heterotaxy in the fetal population remains scarce. Here, we aimed to investigate the clinical characteristics and genetic spectrum of a fetal cohort with heterotaxy.

Methods: We retrospectively investigated all fetuses with a prenatal diagnosis of heterotaxy at a single center between October 2015 and November 2020. These cases were studied using the genetic testing data acquired from a combination of copy number variation sequencing (CNV-seq) and whole-exome sequencing (WES), and their clinical phenotypes were also reviewed.

Result: A total of 72 fetuses diagnosed with heterotaxy and complete clinical and genetic results were enrolled in our research. Of the 72 fetuses, 18 (25%) and 54 (75%) had left and right isomerism, respectively. Consistent with the results of a previous study, intracardiac anomalies were more severe in patients with right atrial isomerism than in those with left atrial isomerism (LAI) and mainly manifested as atrial situs inversus, bilateral right atrial appendages, abnormal pulmonary venous connection, single ventricles or single atria, and pulmonary stenosis or atresia. In 18 fetuses diagnosed with LAI, the main intracardiac anomalies were bilateral left atrial appendages. Of the 72 fetuses that underwent CNV-seq and WES, 11 (15.3%) had positive genetic results, eight had definitive pathogenic variants, and three had likely pathogenic variants. The diagnostic genetic variant rate identified using WES was 11.1% (8/72), in which primary ciliary dyskinesia (PCD)-associated gene mutations (CCDC40, CCDC114, DNAH5, DNAH11, and ARMC4) accounted for the vast majority (n = 5). Other diagnostic genetic variants, such as KMT2D and FOXC1, have been rarely reported in heterotaxy cases, although they have been verified to play roles in congenital heart disease.

Conclusion: Thus, diagnostic genetic variants contributed to a substantial fraction in the etiology of fetal heterotaxy. PCD mutations accounted for approximately 6.9% of heterotaxy cases in our fetal cohort. WES was identified as an effective tool to detect genetic causes prenatally in heterotaxy patients.

Spectrum of Genetic Variants in a Cohort of 37 Laterality Defect Cases

Laterality defects are defined by the perturbed left–right arrangement of organs in the body, occurring in a syndromal or isolated fashion. In humans, primary ciliary dyskinesia (PCD) is a frequent underlying condition of defective left–right patterning, where ciliary motility defects also result in reduced airway clearance, frequent respiratory infections, and infertility. Non-motile cilia dysfunction and dysfunction of non-ciliary genes can also result in disturbances of the left–right body axis. Despite long-lasting genetic research, identification of gene mutations responsible for left–right patterning has remained surprisingly low. Here, we used whole-exome sequencing with Copy Number Variation (CNV) analysis to delineate the underlying molecular cause in 35 mainly consanguineous families with laterality defects. We identified causative gene variants in 14 families with a majority of mutations detected in genes previously associated with PCD, including two small homozygous CNVs. None of the patients were previously clinically diagnosed with PCD, underlining the importance of genetic diagnostics for PCD diagnosis and adequate clinical management. Identified variants in non-PCD-associated genes included variants in PKD1L1 and PIFO, suggesting that dysfunction of these genes results in laterality defects in humans. Furthermore, we detected candidate variants in GJA1 and ACVR2B possibly associated with situs inversus. The low mutation detection rate of this study, in line with other previously published studies, points toward the possibility of non-coding genetic variants, putative genetic mosaicism, epigenetic, or environmental effects promoting laterality defects.

A change of heart: new roles for cilia in cardiac development and disease

Although cardiac abnormalities have been observed in a growing class of human disorders caused by defective primary cilia, the function of cilia in the heart remains an underexplored area. The primary function of cilia in the heart was long thought to be restricted to left-right axis patterning during embryogenesis. However, new findings have revealed broad roles for cilia in congenital heart disease, valvulogenesis, myocardial fibrosis and regeneration, and mechanosensation. In this Review, we describe advances in our understanding of the mechanisms by which cilia function contributes to cardiac left-right axis development and discuss the latest findings that highlight a broader role for cilia in cardiac development. Specifically, we examine the growing line of evidence connecting cilia function to the pathogenesis of congenital heart disease. Furthermore, we also highlight research from the past 10 years demonstrating the role of cilia function in common cardiac valve disorders, including mitral valve prolapse and aortic valve disease, and describe findings that implicate cardiac cilia in mechanosensation potentially linking haemodynamic and contractile forces with genetic regulation of cardiac development and function. Finally, given the presence of cilia on cardiac fibroblasts, we also explore the potential role of cilia in fibrotic growth and summarize the evidence implicating cardiac cilia in heart regeneration.

Primary Ciliary Dyskinesia: A Rare and Often Underdiagnosed Disease

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disease with clinical features of ear, sinus, and pulmonary infections that overlap with common respiratory illnesses of childhood. It is a progressive disorder that has significant influence on quality of life, lung function, and survival. Given the considerable overlap of symptoms between common illnesses and PCD, a high index of suspicion by primary care providers is needed to consider the diagnosis. There is not a single "gold standard" diagnostic test for PCD and multiple diagnostic methods coupled with specialized expertise is often needed to make the diagnosis. Patients with PCD also have comorbidities requiring a multidisciplinary approach for optimal clinical management. It is important for primary care physicians to recognize the PCD clinical phenotype and have a diagnostic framework for these patients. [Pediatr Ann. 2022;51(2):e82-e85.].

Full-Face Mask Use during SCUBA Diving Counters Related Oxidative Stress and Endothelial Dysfunction

Impaired flow mediated dilation (FMD), an index of vascular stress, is known after SCUBA diving. This is related to a dysfunction of nitric oxide (NO) availability and a disturbance of the redox status, possibly induced by hyperoxic/hyperbaric gas breathing. SCUBA diving is usually performed with a mask only covering “half face” (HF) and therefore forcing oral breathing. Nasal NO production is involved in vascular homeostasis and, as consequence, can significantly reduce NO possibly promoting vascular dysfunction. More recently, the utilization of “full-face” (FF) mask, allowing nasal breathing, became more frequent, but no reports are available describing their effects on vascular functions in comparison with HF masks. In this study we assessed and compared the effects of a standard shallow dive (20 min at 10 m) wearing either FF or a HF mask on different markers of vascular function (FMD), oxidative stress (ROS, 8-iso-PGF2α) and NO availability and metabolism (NO₂, NOx and 3-NT and iNOS expression). Data from a dive breathing a hypoxic (16% O₂ at depth) gas mixture with HF mask are shown allowing hyperoxic/hypoxic exposure. Our data suggest that nasal breathing might significantly reduce the occurrence of vascular dysfunction possibly due to better maintenance of NO production and bioavailability, resulting in a better ability to counter reactive oxygen and nitrogen species. Besides the obvious outcomes in terms of SCUBA diving safety, our data permit a better understanding of the effects of oxygen concentrations, either in normal conditions or as a strategy to induce selected responses in health and disease.

Axonemal Symmetry Break, a New Ultrastructural Diagnostic Tool for Primary Ciliary Dyskinesia?

Diagnosis testing for primary ciliary dyskinesia (PCD) requires a combination of investigations that includes study of ciliary beat pattern by high-speed video-microscopy, genetic testing and assessment of the ciliary ultrastructure by transmission electron microscopy (TEM). Historically, TEM was considered to be the “gold standard” for the diagnosis of PCD. However, with the advances in molecular genetic techniques, an increasing number of PCD variants show normal ultrastructure and cannot be diagnosed by TEM. During ultrastructural assessment of ciliary biopsies of patients with suspicion of PCD, we observed an axonemal defect not previously described that affects peripheral doublets tilting. To further characterize this defect of unknown significance, we studied the ciliary axonemes by TEM from both PCD-confirmed patients and patients with other sino-pulmonary diseases. We detected peripheral doublets tilting in all the PCD patients, without any significant difference in the distribution of ciliary beat pattern or mutated gene. This defect was also present in those patients with normal ultrastructure PCD subtypes. We believe that the performance of axonemal asymmetry analysis would be helpful to enhance diagnosis of PCD.

Feasibility of nasal NO screening in healthy newborns

BACKGROUND

Nasal nitric oxide (nNO) measurement is recommended as a first line screening test for primary ciliary dyskinesia (PCD). While reliable velum- and non-velum-closure techniques exist for preschool children and older individuals, no data are available for neonates.

AIMS

To determine feasibility of nNO screening and nNO concentration in healthy newborns in the first week of life.

METHODS

Nasal NO was analyzed in tidal breathing during natural sleep using a CLD-88 sp NO analyzer (chemoluminescence sensor) and a NIOX MINO (electrochemical sensor). Test success and nNO concentration were determined and compared between the two devices.

RESULTS

Nasal NO was measured in 62 healthy neonates within the first week of life. Feasibility of nNO measurement was 100% for at least one nostril and 85.5% for both nostrils using the chemoluminescence device, but significantly lower with the electrochemical device (85.5% and 53.2%; p < .001). Median nNO concentration was 38 ppb (interquartile range, 27-55; range, 9-100) with the ECOMEDICS device and 23 (15-33, 8-59) with the NIOX MINO (p < .001), with a trend towards higher values for older subjects. None of the subjects exceeded nNO levels of 100 ppb.

CONCLUSION

Measurement of nNO using a chemoluminescence device is highly feasible in newborns during natural sleep. However, nNO levels are considerably lower compared to the published data for older individuals and in the range of a PCD reference group of infants between 4 and 8 weeks of age, potentially resulting in a great overlap with subjects with PCD in this age group. Therefore, screening for PCD using nasal NO might not be useful in the first week of life. Upon clinical suspicion, other diagnostic tests such as high-speed video analysis of the cilia should be applied.

CCDC40 mutation as a cause of infertility in a Chinese family with primary ciliary dyskinesia

TRIAL DESIGN

Primary ciliary dyskinesia (PCD) is a genetical disease that inherited in an autosomal-recessive way. Its clinical manifestations (such as male infertility) are mainly caused by defects of motion-related cilia that encoded by mutated genes. Although some mutation has been verified, a number of mutations of PCD remain elusive. The main purpose of this study is to identify mutant genes in a Chinese family with PCD, and to verify the safety and effectiveness of intracytoplasmic sperm injection (ICSI) of infertility caused by PCD.

METHODS

Imaging examination was used to exclude pulmonary inflammation and visceral translocation. Semen analysis was used to assess the quality of the proband's sperm. Transmission electron microscopy (TEM) was conducted to assess the ultrastructure of flagella and cilia. Targeted next generation sequencing and Sanger sequencing and qPCR (real-time quantitative polymerase chain reaction detecting system) were applied to identified mutation of Chinese Family suspected of having PCD. Viable sperm were selected by hypo-osmotic swelling test (HOST) for ICSI.

RESULTS

We report 2 novel mutations in CCDC40 gene (c.1259delA and EX17_20 deletion) resulted in immobility of sperm and infertility of the proband. These mutations were confirmed in the proband's sister (heterozygous) and his parents (recessive carrier) by Sanger sequencing and qPCR. All the spermatozoa from the proband were immotile. Ultrastructural defects were found in flagella and cilia of proband and his sister. Viable sperms were selected by HOST for ICSI and fertilized 9 of 21 eggs. Two frozen embryos were transplanted and a healthy 3500 g boy was delivered at 40 + 4 weeks' gestation. And then, we summarized the genes related to PCD and the mutant sites of CCDC40 gene.

CONCLUSION

We reported 2 novel mutants in CCDC40 gene (c.1259delA and EX17_20 deletion), which could be candidates for genetic diagnosis in PCD patients. The combination of targeted next generation sequencing and Sanger sequencing may be a useful tool to diagnose PCD. ICSI is a considerable method in treatment of infertility caused by PCD.

Update on genetic screening and treatment for infertile men with genetic disorders in the era of assisted reproductive technology

A genetic etiology of male infertility is identified in fewer than 25% of infertile men, while 30% of infertile men lack a clear etiology, resulting in a diagnosis of idiopathic male infertility. Advances in reproductive genetics have provided insights into the mechanisms of male infertility, and a characterization of the genetic basis of male infertility may have broad implications for understanding the causes of infertility and determining the prognosis, optimal treatment, and management of couples. In a substantial proportion of patients with azoospermia, known genetic factors contribute to male infertility. Additionally, the number of identified genetic anomalies in other etiologies of male infertility is growing through advances in whole-genome amplification and next-generation sequencing. In this review, we present an up-to-date overview of the indications for appropriate genetic tests, summarize the characteristics of chromosomal and genetic diseases, and discuss the treatment of couples with genetic infertility by microdissection-testicular sperm extraction, personalized hormone therapy, and in vitro fertilization with pre-implantation genetic testing.

Modelling of primary ciliary dyskinesia using patient-derived airway organoids

Patient-derived human organoids can be used to model a variety of diseases. Recently, we described conditions for long-term expansion of human airway organoids (AOs) directly from healthy individuals and patients. Here, we first optimize differentiation of AOs towards ciliated cells. After differentiation of the AOs towards ciliated cells, these can be studied for weeks. When returned to expansion conditions, the organoids readily resume their growth. We apply this condition to AOs established from nasal inferior turbinate brush samples of patients suffering from primary ciliary dyskinesia (PCD), a pulmonary disease caused by dysfunction of the motile cilia in the airways. Patient-specific differences in ciliary beating are observed and are in agreement with the patients' genetic mutations. More detailed organoid ciliary phenotypes can thus be documented in addition to the standard diagnostic procedure. Additionally, using genetic editing tools, we show that a patient-specific mutation can be repaired. This study demonstrates the utility of organoid technology for investigating hereditary airway diseases such as PCD.

Identification of Two Novel DNAAF2 Variants in Two Consanguineous Families with Primary Ciliary Dyskinesia

Background

Dynein axonemal assembly factor 2 (DNAAF2) is involved in the early preassembly of dynein in the cytoplasm, which is essential for motile cilia function. Primary ciliary dyskinesia (PCD) associated with DNAAF2 variants has rarely been reported in females with infertility. Moreover, there is no report linking DNAAF2 to scoliosis in human.

Materials and Methods

We recruited patients from two consanguineous families with a clinical diagnosis of PCD and collected their clinical history, laboratory tests, and radiographic data. Sequencing and bioinformatics analysis were then performed. Immunofluorescence and high-speed microscope analysis were used to support the pathogenicity of the variant.

Results

Proband 1, a 26-year-old female from family I, exhibited scoliosis, bronchiectasis, sinusitis, situs inversus, and infertility. We found a novel homozygous missense variant in DNAAF2, c.491T>C, p.(Leu164Pro) in this patient. Subsequent immunofluorescence indicated the absence of outer dynein arm and inner dynein arm of cilia, and high-speed microscopy analysis showed that the most of the cilia are static, which support the pathogenicity of this variant. Proband 2, a 53-year-old female, presented with bronchiectasis, sinusitis, and infertility. In this patient, a new homozygous frameshift variant DNAAF2, c.822del, p.(Ala275Profs*10) was identified. The disease-causing variants mentioned above are not included in the current authorized genetic databases.

Conclusion

Our findings expand the spectrum of DNAAF2 variants and link DNAAF2 to female infertility and likely scoliosis in patients with PCD.

Genetic animal models of scoliosis: A systematical review

Scoliosis is a complex disease with undetermined pathogenesis and has a strong relationship with genetics. Models of scoliosis in animals have been established for better comprehending its pathogenesis and treatment. In this review, we searched all the genetic animal models with body curvature in databases, and reviewed the related genes and scoliosis types. Meanwhile, we also summarized the pathogenesis of scoliosis reported so far. Summarizing the positive phenotypic animal models contributes to a better understanding on the pathogenesis of scoliosis and facilitates the selection of experimental models when a possible pathogenic factor is concerned.

[Isomorfismo cardiaco: Una perspectiva multidisciplinaria]

Atrial isomerism describes complex anatomical findings with defects in the determination of lateralization; being a rare situation, with a prevalence of 1 in every 10.000 to 20.000 live births, with an incidence of up to 4% of all cardiac malformations. The diagnosis can be made in the neonatal age; however, clinical presentation is nonspecific. Depending on the spectrum of malformations, complex and invasive diagnostic tools may be required. Treatment is varied and can range from palliative surgery in view of univentricular physiology to total correction surgery for biventricular repair.

A Study on the Genetics of Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a poorly understood disorder. It is primarily autosomal recessive and is prevalent in tribal communities of the United Arab Emirates due to consanguineous marriages. This retrospective study aimed to assess the pathogenicity of the genetic variants of PCD in indigenous patients with significant clinical respiratory problems. Pathogenicity scores of variants obtained from the chart review were consolidated using the Ensembl Variant Effect Predictor. The multidimensional dataset of scores was clustered into three groups based on their pathogenicity. Sequence alignment and the Jensen–Shannon Divergence (JSD) were generated to evaluate the amino acid conservation at the site of the variation. One-hundred and twelve variants of 28 genes linked to PCD were identified in 66 patients. Twenty-two variants were double heterozygous, two triple heterozygous, and seven homozygous. Of the thirteen novel variants, two, c.11839 + 1G > A in dynein, axonemal, heavy chain 11 (DNAH11) and p.Lys92Trpfs in dynein, axonemal, intermediate chain 1 (DNAI1) were associated with dextrocardia with situs inversus, and one, p.Gly21Val in coiled-coil domain-containing protein 40 (CCDC40), with absent inner dynein arms. Homozygous C1orf127:p.Arg113Ter (rs558323413) was also associated with laterality defects in two related patients. The majority of variants were missense involving conserved residues with a median JSD score of 0.747. Homology models of two deleterious variants in the stalk of DNAH11, p.Gly3102Asp and p.Leu3127Arg, revealed structural importance of the conserved glycine and leucine. These results define potentially damaging PCD variants in the region. Future studies, however, are needed to fully comprehend the genetic underpinnings of PCD.