Primary Ciliary Dyskinesia Research Articles

Airway ciliary microenvironment responses in mice with primary ciliary dyskinesia and central pair apparatus defects

Airway ciliary microenvironment responses in mice with primary ciliary dyskinesia and central pair apparatus defects

Eosinophilic Pneumonia Triggered by Toxocara canis in a Patient with Primary Ciliary Dyskinesia: A Clinical Case Report

Eosinophilic Pneumonia Triggered by Toxocara canis in a Patient with Primary Ciliary Dyskinesia: A Clinical Case Report

Uplift of genetic diagnosis of rare respiratory disease using airway epithelium transcriptome analysis.

Rare genetic respiratory disease has an incidence rate of more than 1:2500 live births in Northern Europe and carries significant disease burden. Early diagnosis improves outcomes, but many individuals remain without a confident genetic diagnosis. Improved and expanded molecular testing methods are required to improve genetic diagnosis rates and thereby improve clinical outcomes. Using primary ciliary dyskinesia (PCD) as an exemplar rare genetic respiratory disease, we developed a standardized method to identify pathogenic variants using whole transcriptome RNA-sequencing (RNA-seq) of nasal epithelial cells cultured at air-liquid interface (ALI). The method was optimized using cells from healthy volunteers, and people with rhino-pulmonary disease but no diagnostic indication of PCD. We validated the method using nasal epithelial cells from PCD patients with known genetic cause. We then assessed the ability of RNA-seq to identify pathogenic variants and the disease mechanism in PCD likely patients but in whom DNA genetic testing was inconclusive. The majority of 49 targeted PCD genes were optimally identified in RNA-seq data from nasal epithelial cells grown for 21days at ALI culture. Four PCD-likely patients without a previous genetic diagnosis received a confirmed genetic diagnosis from the findings of the RNA-seq data. We demonstrate the clinical potential of RNA-seq of nasal epithelial cells to identify variants in individuals with genetically unsolved PCD. This uplifted genetic diagnosis should improve genetic counselling, enables family cascade screening, opens the door to potential personalised treatment and care approaches. This methodology could be implemented in other rare lung diseases such as cystic fibrosis.

Novel variants in DNAH9 are present in two infertile patients with severe asthenospermia.

Asthenospermia is a type of sperm that has malformed sperm with movement disorders that lead to male infertility. DNAH9 is a member of the dynein family and a central part of the outer dynein arm of cilia and flagella. DNAH9 gene defects are associated with primary ciliary dyskinesia and ultrastructural abnormalities in ciliary axial ultrastructure. However, the role of DNAH9 in sperm motility remains unclear, prompting us to investigate its function in spermatozoa. Familial Sanger sequencing showed that sterile males carried homozygous DNAH9 variants (c. 12218A>C, p. N4073T) and compound heterozygous variants (c.8617G>A, p.V2873M; c.11742A>T, p.E3914D), respectively. Transmission electron microscopy revealed these variants resulted in a significant lack of outer dynein arms in the cross-sectional view of the axoneme in both patients. Immunofluorescence results showed that these variants can lead to decline in DNAH9 protein expression, which led to the dysfunction of flagellar ultrastructure-related proteins, including DNAI1, DNAH1 and DNAH10. In conclusion, we identified novel biallelic variants in DNAH9 that likely bring about sharply decreased motility of spermatozoa in the two patients with asthenospermia. Our findings will widen the variant spectrum of known DNAH9 variants involving asthenospermia and further offer more proofs for genetic counseling and diagnosis.

Life-long functional regeneration of in vivo airway epithelium by the engraftment of airway basal stem cells.

Durable and functional regeneration of the airway epithelium in vivo with transplanted stem cells has the potential to reconstitute healthy tissue in diseased airways, such as in cystic fibrosis or primary ciliary dyskinesia. Here, we present detailed protocols for the preparation and culture expansion of murine primary and induced pluripotent stem cell-derived airway basal stem cells (iBCs) and methods for their intra-airway transplantation into polidocanol-conditioned murine recipients to achieve durable in vivo airway regeneration. Reconstitution of the airway tissue resident epithelial stem cell compartment of immunocompetent mice with syngeneic donor cells leverages the extensive self-renewal and multipotent differentiation properties of basal stem cells (BCs) to durably generate a broad diversity of mature airway epithelial lineages in vivo. Engrafted donor-derived cells re-establish planar cell polarity as well as functional ciliary transport. By using this same approach, human primary BCs or iBCs transplanted into NOD-SCID gamma recipient mice similarly display engraftment and multilineage airway epithelial differentiation in vivo. The time to generate mouse or human iBCs takes ~60 d, which can be reduced to ~20 d if previously differentiated cells are thawed from cryopreserved iBC archives. The tracheal conditioning regimen and cell transplantation procedure is completed in 1 d. A competent graduate student or postdoctoral trainee should be able to perform the procedures listed in this protocol.

Proliferation associated 2G4 is required for the ciliation of vertebrate motile cilia

Motile cilia are critical structures that regulate early embryonic development and tissue homeostasis through synchronized ciliary motility. The formation of motile cilia is dependent on precisely controlled sequential processes including the generation, migration, and docking of centrioles/basal bodies as well as ciliary growth. Using the published proteomics data from various organisms, we identified proliferation-associated 2G4 as a novel regulator of ciliogenesis. Loss-of-function studies using Xenopus laevis as a model system reveal that Pa2G4 is essential for proper ciliogenesis and synchronized movement of cilia in multiciliated cells (MCCs) and the gastrocoel roof plate (GRP). Pa2G4 morphant MCCs exhibit defective basal body docking to the surface as a result of compromised Rac1 activity, apical actin network formation, and immature distal appendage generation. Interestingly, the regions that include the RNA-binding domain and the C-terminus of Pa2G4 are necessary for ciliogenesis in both MCCs and GRP cells. Our findings may provide insights into motile cilia-related genetic diseases such as Primary Ciliary Dyskinesia.

Ciliopathy Organoid Models - a Comprehensive Review.

Cilia are membrane-bound organelles found on the surface of most mammalian cell types and play numerous roles in human physiology and development, including osmo- and mechanosensation, as well as signal transduction. Ciliopathies are a large group of - usually rare - genetic disorders resulting from abnormal ciliary structure or ciliary dysfunction that have a high collective prevalence. Autosomal dominant or recessive polycystic kidney disease (ADPKD/ARPKD), Bardet-Biedl-Syndrome and primary ciliary dyskinesia (PCD) are the most frequent etiologies. Rodent and zebrafish models have improved the understanding of ciliopathy pathophysiology. Yet, the limitations of these genetically modified animal strains include the inability to fully replicate the phenotypic heterogeneity found in humans, including variable multi-organ involvement. Organoids, self-assembled 3D-cell-based models derived from human induced pluripotent stem cells (iPSCs) or primary tissues, can recapitulate certain aspects of the development, architecture, and function of the target organ in the dish. The potential of organoids to model patient-specific genotype-phenotype correlations has increased their popularity in ciliopathy research and led to the first preclinical organoid-based ciliopathy drug screens. This review comprehensively summarizes and evaluates current ciliopathy organoid models, focusing on kidney, airway, liver, and retinal organoids, as well as the specific methodologies used for their cultivation and for interrogating ciliary dysfunction.

Laparoscopic cholecystectomy in a patient with Kartagener syndrome having multiple cystic arteries: a case report

Introduction and importance: Situs inversus totalis (SIT) is a rare condition that involves transposition of thoracic and abdominal viscera. It is associated with Kartagener syndrome (KS) that comprises a triad of SIT, bronchiectasis, and chronic sinusitis. Considering this anatomical variation, it poses a technical challenge for right-handed surgeons performing laparoscopic cholecystectomy. This is the only case report for a patient having KS presenting for cholelithiasis found to have multiple cystic arteries during surgery. Case presentation: A 55-year-old man with KS, known to have bronchiectasis, presented with nonspecific diffuse upper abdominal pain and positive murphy sign on the left. Biliary colic with cholelithiasis was diagnosed using ultrasound of the abdomen. The patient was admitted to the surgical floor for persistent biliary colic and was planned for laparoscopic cholecystectomy. The cholecystectomy was done by a single right-handed surgeon, and the patient was discharged on the next day. Clinical discussion: The American laparoscopic cholecystectomy technique with reversed mirror-image of routine laparoscopic cholecystectomy port sites was adopted. The operative team including the operating surgeon and camera operator were on the patient’s right side, and the laparoscopic devices with the technician nurse were located on the left side for safer dissection and easier access to the different structures. The procedure was complicated by the Calot triangle anatomy variation along with the presence of three cystic arteries and one cystic duct. The surgery was completed within 50 minutes, a shorter duration compared to other reported cases. Conclusion: Laparoscopic cholecystectomy in patients with SIT is a challenging, technically demanding procedure due to anatomical inversion and structural variations. The surgeon must modify various technical steps to perform this procedure successfully and dissect the gallbladder and its structures. A good knowledge of anatomy and a skillful dissection intraoperatively remain the gold standards for a successful outcome with minimal complications.

Primary ciliary dyskinesia in children: clinical, laboratory-instrumental and genetic characteristics

Primary ciliary dyskinesia in children: clinical, laboratory-instrumental and genetic characteristics

Novel CYCLIN-O pathogenic variants in a patient presenting with bronchiectasis secondary to reduced generation of multiple motile cilia.

Reduced generation of multiple motile cilia (RGMC) represents a rare variant of Primary Ciliary Dyskinesia (PCD), associated with CYCLIN-O (CCNO) mutations. We report a novel compound mutation in the CCNO gene in an adult Chinese Singaporean exhibiting chronic productive cough since childhood and recurrent sino-pulmonary infections. Low nasal nitric oxide and bronchiectasis suggests PCD. Bronchoscopy for epithelial and nasal brushings for ciliary studies were repeated after adequate treatment of lower respiratory tract infections. Demonstration of oligo-cilia via transmission electron microscopy, and detection of CCNO mutation through genetic analysis were utilized to diagnose RGMC. Repeated courses of antibiotics including nebulised antibiotics were used to treat recurrent infections and exacerbations. Airway clearance techniques, immunizations and collaboration with otorhinolaryngologist form part of the long-term management. Heightened clinical suspicion and adherence to established diagnostic algorithms are essential for timely recognition of this entity.

Incidence of primary ciliary dyskinesia: A study across diverse communities.

Incidence of primary ciliary dyskinesia: A study across diverse communities.

Understanding primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is a rare, inherited disease characterized by impaired motile ciliary function leading to chronic sinopulmonary disease, persistent middle ear effusions, laterality defects, and subfertility. Over fifty PCD-associated genes have also been identified, which have provided new insights into the processes involved into ciliary assembly, structure, and function. Historically, the diagnosis of PCD was based on the presence of ultrastructural defects in the ciliary axoneme but with identification of a growing number of disease-associated genes, genetic testing has become a first-line diagnostic tool. Other approaches have also evolved, that have improved our diagnostic capabilities. Treatments for PCD have lagged, and though our growing understanding of the genetic and pathophysiological bases of the disease of PCD may yield to better therapeutic strategies.

Multiomic comparison of GLP1R analogues interaction networks

Abstract Background GLP1R analogs are drugs increasingly used in clinical practice in patients with type 2 diabetes, and obesity. Subsequent clinical trials indicate their beneficial effects, including cardioprotection, but the exact mechanisms of those actions are still not known. Aim of the study: This study aims to understand how GLP1R analogs exert cardioprotective and therapeutic effects in patients with type 2 diabetes and obesity. Through analyzing GLP1R interaction networks and associated metabolomic and lipidomic data, we seek to uncover the molecular mechanisms underlying these effects and their potential therapeutic implications. Methods We performed an integrative analysis of four GLP1Ri interaction networks and associated metabolomic and lipidomic datasets. Interactomics revealed 130 common genes among semaglutide, exenatide, tirzapeptide, and retatrutide, primarily associated with diabetes-related processes, including obesity and hyperglycemia. Noteworthy findings encompassed ontological terms related to cardiovascular diseases (CVDs), such as hypertension, calcium regulation in cardiac cells, and amino acid accumulation-induced mTOR activation. Additionally, enrichment in gene sets linked to longevity, less recognized terms like fatty liver disease, chemokine signaling, and sirtuin interactome, were observed. Results Specific processes for tirzepatide included behavior-related terms and hydrochloric acid secretion, while retatrutide exhibited associations with fibrosarcoma, thinking and speaking disturbances, and adipogenesis signaling. Shared processes like primary ciliary dyskinesia differed in implicated genes. Metabolomics identified shared metabolites associated with diverse pathways, including galactose metabolism and nitric oxide-related pathways. Lipidomics highlighted enriched phenotypes and pathways, such as arachidonic acid metabolism and cholesterol biosynthesis. Conclusion Integration of interaction networks with metabolomic and lipidomic data revealed top interactors and impacted metabolites, shedding light on the intricate molecular landscape of GLP1Ri. These findings contribute valuable insights into the potential therapeutic implications and broader health considerations of GLP1R drugsfig1fig2

Genetic Variants Supporting the Diagnosis of Primary Ciliary Dyskinesia in Japan.

Primary ciliary dyskinesia (PCD; OMIM 244400) is a rare genetic disorder affecting motile cilia and is characterized by impaired mucociliary clearance in the airway epithelium that leads to chronic oto-sinopulmonary manifestations. To date, over 50 PCD-causing genes have been identified, with these genes and their variants varying globally across populations. We performed targeted resequencing of 42 PCD-causative genes in 150 Japanese patients suspected of having PCD and identified pathogenic or likely pathogenic variants in 51 patients. Among these, 24 patients exhibited a homozygous deletion of DRC1 exons 1-4, the most common cause of PCD in Japan. The allele frequency of this deletion was estimated at 0.0034 (95% CI: 0.0025-0.0044), based on bioinformatic analysis of 7906 whole-genome sequences from the general Japanese population. Additionally, RNA sequencing of nasal samples supplemented in silico variant predictions, aiding in the identification of causative variants. Considering potential ethnic differences, it is essential to accumulate global data on these variants and their functional impacts.

Direct Comparison of Quality of Life in Patients with Allergic Rhinitis Undergoing Sublingual Versus Subcutaneous Immunotherapy.

Background/Objectives: Subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are commonly used for allergic rhinitis (AR), yet limited research has directly compared their effects on quality of life (QoL). We aimed to assess QoL differences between SLIT and SCIT recipients. As both forms of immunotherapy have reported benefits, we hypothesize that patients undergoing SLIT and SCIT will have comparable QoL improvements. Methods: A cohort study included patients with AR treated with immunotherapy from 2018 to 2022. Patients with obstructive sleep apnea, primary ciliary dyskinesia, cystic fibrosis, vasculitis, rheumatoid arthritis, sarcoidosis, or lupus were excluded. QoL was evaluated using the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) at multiple time points. Demographics, additional therapies, and allergen sensitivities were recorded. Data were analyzed using SPSS Statistics. Results: A total of 41 participants were eligible for inclusion. Both SLIT and SCIT groups exhibited reductions from baseline RQLQ scores. Within SLIT recipients, 5/7 RQLQ domains significantly improved. SCIT recipients showed significant QoL enhancement in 3/7 domains. The mean difference between SLIT and SCIT cohorts was -0.18 (p = 0.57, d = -0.18, 95% CI [-0.79, 0.43] at a mean treatment time of 18 months. Conclusions: SLIT and SCIT showed comparable RQLQ score reductions after 18 months of therapy, suggesting similar QoL benefits between the two treatment paradigms. Further investigation is needed to explore SLIT vs. SCIT differences in long-term QoL improvements beyond two years.

Long-Term Lung Function and Pseudomonas aeruginosa Infection in Genotyped Primary Ciliary Dyskinesia.

Rationale: Primary ciliary dyskinesia is a rare genetic disorder characterized by progressive lung disease. Pseudomonas aeruginosa is a major pathogen in this disease, known to impact lung function. Previous genotype-phenotype studies have been limited by cross-sectional designs, isolated adult or pediatric populations, small numbers, or short follow-up durations. Objectives: We aimed to explore long-term lung function in primary ciliary dyskinesia grouped by genotypes and ultrastructural defects, considering the influence of P. aeruginosa. Methods: In this retrospective, observational study, we analyzed 43 years of spirometry and 20 years of microbiology data. Using linear mixed-effects models, we estimated FEV1 z-score trends and compared them at ages 10, 25, and 50 years, while Generalized Estimating Equations were used to assess P. aeruginosa prevalence between groups. In a secondary analysis, we matched spirometry and microbiology samples to evaluate the influence of P. aeruginosa on lung function. Measurements and Main Results: We included 127 genotyped subjects, 6,691 spirometries and 10,082 microbiology samples. CCDC39 and CCDC40 variants showed early onset and sustained decline in lung function, while DNAH11 and HYDIN variants demonstrated relative stability. Lung function in the proximity of positive P. aeruginosa cultures were on average 0.06 z-score lower. Despite this, differences between groups remained largely unaffected by P. aeruginosa. Conclusion: Long-term lung function in primary ciliary dyskinesia follows discrete genotype specific profiles and appear independent of P. aeruginosa infection. We confirm and extend previous findings of CCDC39 and CCDC40 as variants associated with early onset severe lung function impairment persisting in the long term.

Microbial Isolates and Antimicrobial Resistance Patterns in Adults with Inborn Errors of Immunity: A Retrospective Longitudinal Analysis of Sputum Cultures

Introduction: Individuals with inborn errors of immunity (IEI) are at increased risk of respiratory infection and frequently receive prolonged broad-spectrum antibiotics, leading to antibiotic resistance. The aim of this study was to identify respiratory pathogens and antibiotic resistance patterns in IEI patients. Methods: We retrospectively studied 36 IEI patients with positive bacterial growth in sputum cultures between 2014 and 2023. Data covered hospitalizations, respiratory infections, yearly antibiotic prescriptions, past sputum cultures, and antibiotic sensitivities. Patients with primary ciliary dyskinesia (PCD) and bronchiectasis served as a control group. Results: A total of 314 sputum cultures were analyzed from patients with IEI, alongside 585 cultures from individuals with PCD and 113 cultures from patients with bronchiectasis. Patients with IEI had a median age of 23.5 years, with 61% male participants. The study compared the differences in bacterial isolates from sputum cultures and antibiotic resistance between patients with IEI and the control groups. The most common bacterial isolates across all groups were Haemophilus influenzae (159 isolates in IEI vs. 314 in PCD and 26 in bronchiectasis), Pseudomonas aeruginosa, and Streptococcus pneumoniae. In IEI patients, 992 symptomatic respiratory exacerbations and 43 pneumonia-related hospitalizations were recorded. Notably, H. influenzae in IEI patients showed high resistance rates to cefuroxime (82%), amoxicillin/clavulanic acid (66%), trimethoprim/sulfamethoxazole (59%), and ampicillin/sulbactam (49%). P. aeruginosa in IEI patients displayed significant resistance to ciprofloxacin (85%), ceftazidime (42%), and aminoglycosides (23–33%). Additionally, all S. pneumoniae isolates in IEI patients were tetracycline resistant, with high resistance rates to penicillin, clindamycin, and erythromycin. It is essential to highlight the substantial resistance of common pathogens to oral antibiotics. In contrast, the control groups exhibited lower resistance rates across all bacterial isolates. Conclusion: Antimicrobial resistance is a growing concern among vulnerable IEI patients. We suggest conducting similar investigations in other regions to address this issue. The findings should inform future infection management guidelines for IEIs.

Delayed Diagnosis of Primary Ciliary Dyskinesia in Low-Middle-Income Countries: The Clinical Value of Nasal Nitric Oxide

Delayed Diagnosis of Primary Ciliary Dyskinesia in Low-Middle-Income Countries: The Clinical Value of Nasal Nitric Oxide

Primary ciliary dyskinesia in children: clinical, laboratory-instrumental and genetic characteristics

Background. Primary ciliary dyskinesia (PCD) is an orphan disease, and diagnosis is difficult because there is no gold standard for diagnosis. Aim. Clinical, laboratory-instrumental, genetic characteristics of PCD in children. Materials and methods. From 2009 to 2024, 31 patients with a genetically confirmed diagnosis of PCD were observed as part of a multicenter, open-ended, descriptive pilot longitudinal study. Examination methods: clinical and anamnestic method; X-ray examination and computed tomography of the chest organs and paranasal sinuses, tracheobronchoscopy; sputum/aspirate cultures of the tracheobroncheal tree with determination of sensitivity to antibiotics; transmission electron microscopy, high-speed video microscopy of the ciliated epithelium, cytological examination of bronchoalveolar lavage; monitoring computer pulse oximetry, echocardiography, audiometry, spirometry with bronchodilator test. Results. Respiratory symptoms in the neonatal period have 80% of children with PCD, lateralization defects – 35%, congenital heart defects – 13%, bronchiectasis – 68%, purulent endobronchitis – 62%, year-round rhinitis – 84%, hearing loss, otitis – 65%. The average age of onset of symptoms was 1 [1; 1] weeks, and the verification of diagnosis was 6 [2,5; 8] years. The main pathogens of chronic respiratory infection with PCD are Haemophilus influenzae, Pseudomonas aeruginosa, Staphylococcus aureus. The most common cause of PCD was biallelic variants of the DNAH5 gene. Conclusion. The diagnosis of PCD should be based on the application of the maximum number of diagnostic tests.

Impact of TAS2R38 polymorphisms on nasal nitric oxide and Pseudomonas infections in primary ciliary dyskinesia: relation to genotype

ObjectivePrimary ciliary dyskinesia (PCD) severity has been related to genotype and levels of nasal nitric oxide (nNO). The most common TAS2R38 haplotypes (PAV/PAV, PAV/AVI, AVI/AVI) encoding the bitter taste receptor...