Medical and Surgical Advancements in the Management of Cystic Fibrosis Chronic Rhinosinusitis

Hypoxia-induced cystic fibrosis transmembrane conductance regulator dysfunction is a universal mechanism underlying reduced mucociliary transport in sinusitis

INTRODUCTION

Hypoxia due to sinus obstruction is a major pathogenic mechanism leading to sinusitis. The objective of the current study is to define the electrophysiologic characteristics of hypoxia in vitro and in vivo.

METHODS

Cystic fibrosis bronchoepithelial cells expressing wild-type cystic fibrosis transmembrane conductance regulator (CFTR) and human sinonasal epithelial cells were exposed to 1% or atmospheric O2 for 24 h. Time-dependent production of cytoplasmic free radicals was measured. Cells were subjected to Ussing chamber and patch clamp technique where CFTR currents were recorded in whole-cell and cell-attached mode for single channel studies. Indices of mucociliary transport (MCT) were measured using micro-optical coherence tomography. In a rabbit hypoxic maxillary sinus model, tissue oxygenation, relative mRNA expression of HIF-1α, pH, sinus potential difference (SPD), and MCT were determined.

RESULTS

Ussing chamber (p < 0.05), whole-cell (p < 0.001), and single channel patch-clamp (p < 0.0001) showed significant inhibition of Cl- currents in hypoxic cells. Cytoplasmic free radicals showed time-dependent elevation peaking at 4 h (p < 0.0001). Airway surface liquid (p < 0.0001), periciliary liquid (p < 0.001), and MCT (p < 0.01) were diminished. Co-incubation with the free radical scavenger glutathione negated the impact of hypoxia on single channel currents and MCT markers. In sinusitis rabbits, mucosa exhibited low tissue oxygenation (p < 0.0001), increased HIF1α mRNA (p < 0.05), reduced pH (p < 0.01), and decreased MCT (p < 0.001). SPD measurements demonstrated markedly diminished transepithelial Cl- transport (p < 0.0001).

CONCLUSION

Hypoxia induces severe CFTR dysfunction via free radical production causing reduced MCT in vitro and in vivo. Improved oxygenation is critical to reducing the impact of persistent mucociliary dysfunction.

Efficacy of Elexacaftor-Tezacaftor-Ivacaftor on chronic rhinosinusitis in cystic fibrosis

PURPOSE

Our work aims to add evidence on the effectiveness of Elexacaftor-Tezacaftor-Ivacaftor on chronic rhinosinusitis in cystic fibrosis.

MATERIALS AND METHODS

We conducted an observational retrospective cohort study at the Cystic Fibrosis Center of a tertiary care hospital to investigate the effect of Elexacaftor-Tezacaftor-Ivacaftor on chronic rhinosinusitis in cystic fibrosis patients, aged 12 or older. The study's endpoints were the change in the occurrence of acute exacerbations of chronic rhinosinusitis, and the variation of the endoscopic and radiologic findings scored using the Lund-Kennedy endoscopic scale, Lund-Mackay, and modified Lund-Mackay radiologic scales, in patients who underwent both pre-treatment and post-treatment examinations.

RESULTS

The study population comprised 136 patients, of which 28 underwent both pre-treatment and post-treatment nasal endoscopy and 15 had pre- and post-treatment CT scans. Elexacaftor-Tezacaftor-Ivacaftor provided a significant improvement in chronic rhinosinusitis. The mean number of acute exacerbations of chronic rhinosinusitis per year in the pre-treatment time was 0.55 versus 0.35 during the treatment (p < 0.0021). The Lund-Kennedy scale had a pre-treatment average score of 4.21 points versus 1.5 points after the start of Elexacaftor-Tezacaftor-Ivacaftor (p < 0.0001). The average Lund-Mackay and modified Lund-Mackay scores in the pre-treatment time were respectively 14.6 and 16.45 points; and after the start of the therapy, they became 5.87 and 6.73 (p < 0.0001).

CONCLUSION

Elexacaftor-Tezacaftor-Ivacaftor was associated with fewer acute exacerbations of chronic rhinosinusitis, and a significant improvement of chronic rhinosinusitis evaluated endoscopically and radiologically. To our knowledge, this is the first study investigating the change in the occurrence of acute exacerbation of chronic rhinosinusitis in patients affected by cystic fibrosis in therapy with Elexacaftor-Tezacaftor-Ivacaftor.

Predictors of Sinonasal Improvement After Highly Effective Modulator Therapy in Adults with Cystic Fibrosis

OBJECTIVES

The 22-question SinoNasal Outcome Test (SNOT-22) assesses chronic rhinosinusitis (CRS) severity. We aimed to identify predictors of SNOT-22 score improvement following highly effective modulator therapy (HEMT) initiation and to corroborate the SNOT-22 minimal clinically important difference (MCID) in adults with cystic fibrosis (CF).

METHODS

Prospective observational data was pooled from four studies across 10 US centers investigating people with CF (PwCF) and CRS. Three studies evaluated HEMT's impact on CRS. For participants enrolled prior to HEMT initiation, SNOT-22 scores were obtained at baseline and after 3-6 months of HEMT. Multivariate regression identified predictors of improvement. Cronbach's alpha and four distribution-based methods were used to assess internal consistency and calculate the MCID of the SNOT-22.

RESULTS

A total of 184 PwCF participated with mean baseline SNOT-22 scores ranging from 18.1 to 56.7. Cronbach's alpha was ≥0.90 across sites. Participants at sites with pre- and post-HEMT data reported improvement in SNOT-22 scores after initiating HEMT (all p < 0.05). Worse baseline SNOT-22 score (odds ratio (OR): 1.05, p < 0.001, 95% CI: 1.02-1.08), F508del homozygosity (OR: 4.30, p = 0.040, 95% CI: 1.14-18.99), and absence of prior modulator therapy (OR: 4.99, p = 0.017, 95% CI: 1.39-20.11) were associated with greater SNOT-22 improvement. The mean MCID calculated via distribution-based methods was 8.5.

CONCLUSION

Worse baseline sinonasal symptoms, F508del homozygosity, and absence of prior modulator therapy predicted greater improvement after HEMT initiation. The mean MCID for SNOT-22 in PwCF is 8.5 points, similar to non-CF individuals with CRS, and provides a threshold specifically for PwCF. The SNOT-22 has strong internal consistency in PwCF.

LEVEL OF EVIDENCE

3 Laryngoscope, 2024.

Safety and Pharmacokinetics of a Ciprofloxacin and Azithromycin Stent for Chronic Rhinosinusitis

OBJECTIVES

Previously, we developed a novel double-coated sinus stent containing ciprofloxacin (inner layer) and azithromycin (outer layer) (CASS), but released drug concentrations were found to be insufficient for clinical usage. Our objectives are to improve drug release of CASS and assess safety and pharmacokinetics in rabbits.

METHODS

Dip coating was used to create the CASS with 2 mg ciprofloxacin and 5 mg azithromycin. A uniformed double coating was assessed with scanning electron microscopy (SEM), and the release patterns of both drugs and lactate dehydrogenase (LDH) assay were evaluated over 14 days in vitro. Safety, tolerability, and pharmacokinetics of the CASS were tested in rabbits through insertion into the maxillary sinus and evaluated with nasal endoscopy, CT scans, histology, blood counts and chemistries, and in vivo drug release.

RESULTS

SEM confirmed the uniformity of the dual coating of ciprofloxacin and azithromycin, and thickness (μm) was found to be 14.7 ± 2.4 and 28.1 ± 4.6, respectively. The inner coated ciprofloxacin showed a sustained release over 14 days (release %) when soaked in saline solution (day 7, 86.2 ± 3.4 vs. day 14,99.2 ± 5.1). In vivo analysis showed that after 12 days, 78.92 ± 7.67% of CP and 84.12 ± 0.45% of AZ were released into the sinus. There were no significant differences in body weight, white blood cell counts, and radiographic changes before and after CASS placement. No significant histological changes were observed compared to the contralateral control side.

CONCLUSION

Findings suggest that the CASS is an effective method for delivering therapeutic levels of antibiotics. Further studies are needed to validate efficacy in a preclinical sinusitis model.

LEVEL OF EVIDENCE

N/A Laryngoscope, 2024.

Surgery for nasal polyposis in cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a life-shortening, autosomal recessive disease that leads to abnormal electrolyte concentration in exocrine secretions. Secretion stasis in paranasal sinuses determines chronic rhinosinusitis (CRS) and nasal polyposis. Endoscopic sinus surgery is used to open the sinuses and allow medical treatment to work properly.

OBJECTIVES

To determine the effects of sinus surgery alone or in combination with medical treatment (non-surgical) compared to medical treatment (non-surgical) alone on both nasal and pulmonary function in people with CF diagnosed with CRS with nasal polyposis. Further, to evaluate the impact of sinus surgery (with or without medical treatment) on hospitalization rates, use of antibiotics and pulmonary exacerbation rates.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and hand searching of journals and conference abstract books. Date of last search: 4 July 2022. We also searched other databases (Pubmed, Embase, World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), Virtual Health Library and ClinicalTrials.gov). Date of last search: 18 September 2022.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing groups who underwent endoscopic sinus surgery and groups with medical treatment alone.

DATA COLLECTION AND ANALYSIS

The review authors independently selected studies, extracted data, assessed the risk of bias and evaluated the certainty of the evidence using GRADE. They contacted the authors of the included study for additional information.

MAIN RESULTS

We identified 66 publications relating to 50 studies from electronic searches. Only one study fulfilled the inclusion criteria, and only limited information was available. In this study, 28 participants aged 19 to 28 years were randomized in equal numbers to either nasal irrigation alone or nasal irrigation with surgery (endoscopic polypectomy with extended sinusotomy). The certainty of the evidence was very low according to the GRADE approach. We are uncertain whether, compared to medical treatment alone, the addition of surgical intervention improves nasal symptoms, or reduces bacterial colonization, the use of antibiotics and pulmonary exacerbations. We are also uncertain whether the addition of surgery to medical treatment leads to changes in pulmonary function. There was one episode of bleeding during surgery that was corrected during the procedure with no further consequences. The study did not report on survival.

AUTHORS' CONCLUSIONS

Very low-certainty evidence means we are not certain if endoscopic sinus surgery to treat chronic rhinosinusitis with nasal polyposis in cystic fibrosis is effective. Future research should be multicentric to increase the number of participants and increase statistical power. Adequate randomization and allocation concealment are important to guarantee that the groups are similar. Blinding, however, may not be possible in an ethical trial; even without blinding, results can achieve high-level evidence if the outcomes used are objective parameters. Future research should follow participants of all ages for at least 12 months to evaluate the evolution of nasal polyposis, its recurrence and how symptoms may return. We also consider mortality an important outcome to be assessed. Future clinical research should consider the effects of cystic fibrosis transmembrane conductance regulators, a new group of drugs that may affect the development of nasal polyps.

Upper Airway Disease in Adults with Cystic Fibrosis in the Era of CFTR Modulators

OBJECTIVES

Chronic rhinosinusitis (CRS) is prevalent in people with cystic fibrosis (PwCF) and is often refractory to treatments. Uncontrolled CRS might negatively impact the lower airways and the quality of life. The aim of this study is to evaluate the burden of cystic fibrosis (CF)-related CRS in the era of CF transmembrane conductance regulator (CFTR) modulators.

METHODS

Adult PwCF were asked to fill in a questionnaire on sinonasal complaints, they underwent a nasal endoscopy, bacteriological sampling, and a CT scan. Afterwards, these outcome measures were compared between patients treated with and without modulators.

RESULTS

In the 122 included patients, CRS was present in 83%. CFTR modulators were prescribed in 48% of the patients, with a median of 10 months since the start of the treatment. Subjectively, the median SNOT-22 score was 16/110. Objectively, a median Lund-Kennedy score of 6/12 and modified Lund-Mackay score of 10/24 were observed. No correlation could be found between SNOT-22 score and other outcome measures including endoscopy and radiology. Altogether, 21% of the patients had controlled disease. When comparing patients treated with and without modulators, significantly lower CT scores (p = 0.0018) and less bacterial colonization (p = 0.0082) were observed in patients receiving modulators.

CONCLUSION

CF-CRS is highly prevalent in our cohort and only the minority of PwCF has a well-controlled disease. A multidisciplinary ENT-pneumology clinic would be beneficial, as there is a high discrepancy between patient-reported symptoms and the extent of the disease. CFTR modulators are promising, as lower CT scores and less bacterial colonization were observed in the modulator group.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 133:2898-2909, 2023.

Advances in Sinus Surgery for Nasal Polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is comprised of a diverse group of endotypes that cause significant morbidity for afflicted patients. While endoscopic sinus surgery helps ameliorate the disease, polyps frequently recur. Newer strategies are intended to provide access for topical steroid irrigations in attempts to improve the disease process and quality of life, and decrease overall recurrence of polyps.

OBJECTIVE

To review the current literature examining the latest surgical approaches for CRSwNP.

METHODS

Review article.

RESULTS

In dealing with the recalcitrant nature of CRSwNP, surgical techniques have simultaneously become more nuanced and aggressive. Bony resection in anatomically unfavorable areas such as the frontal, maxillary, and sphenoid outflow regions, replacing diseased or denuded mucosa with healthy grafts or flaps at the neo-ostia, and introducing drug-eluting biomaterials to newly opened sinus outflow tracts are highlights in the recent advancements in sinus surgery for CRSwNP. The Draf 3 or modified endoscopic Lothrop procedure has become a standard technique and demonstrated to improve quality of life and decrease polyp recurrence. A number of mucosal grafting or mucosal flap techniques have been described that cover exposed bone of the neo-ostium and evidence shows that this improves healing and diameter of the Draf 3. Partial middle turbinectomy, while controversial, appears to help decrease polyp recurrence in long-term follow-up studies. Modified endoscopic medial maxillectomy improves access to the maxillary sinus mucosa, facilitates debridement and, particularly, in the cystic fibrosis nasal polyp patient, improves overall management of the disease. Sphenoid drill-out procedure provides wider access for topical steroid irrigations and also may improve management of CRSwNP.

CONCLUSION

Surgical intervention remains a mainstay of therapy for CRSwNP. Newer techniques revolve around improving access for topical steroid therapy.

Cystic Fibrosis Foundation otolaryngology care multidisciplinary consensus recommendations

BACKGROUND

Cystic fibrosis (CF) is a multisystem disease that often requires otolaryngology care. Individuals with CF commonly have chronic rhinosinusitis but also present with hearing loss and dysphonia. Given these manifestations of CF, otolaryngologists are frequently involved in the care of patients with CF; however, there is limited consensus on optimal management of sinonasal, otologic, and laryngologic symptoms.

METHODS

The Cystic Fibrosis Foundation convened a multidisciplinary team of otolaryngologists, pulmonologists, audiologists, pharmacists, a social worker, a nurse coordinator, a respiratory therapist, two adults with CF, and a caregiver of a child with CF to develop consensus recommendations. Workgroups developed draft recommendation statements based on a systematic literature review, and a ≥80% consensus was required for acceptance of each recommendation statement.

RESULTS

The committee voted on 25 statements. Eleven statements were adopted recommending a treatment or intervention, while five statements were formulated recommending against a specific treatment or intervention. The committee recommended eight statements as an option for select patients in certain circumstances, and one statement did not reach consensus.

CONCLUSION

These multidisciplinary consensus recommendations will help providers navigate decisions related to otolaryngology consultation, medical and surgical management of CF-CRS, hearing, and voice in individuals with CF. A collaborative and multidisciplinary approach is advocated to best care for our patients with CF. Future clinical research is needed utilizing standardized, validated outcomes with comprehensive reporting of patient outcome, effects of modulator therapies, and genetic characteristics to help continue to advance care, decrease morbidity, and improve the quality of life for individuals with CF.

Elexacaftor-Tezacaftor-Ivacaftor Treatment Reduces Abdominal Symptoms in Cystic Fibrosis-Early results Obtained With the CF-Specific CFAbd-Score

Background: The novel and highly effective CFTR modulator combination of elexacaftor-tezacaftor-ivacaftor (ETI) has been shown to improve lung function and body weight in people with Cystic Fibrosis (pwCF) carrying a F508del mutation. However, the impact of these modulators on gastrointestinal (GI) symptoms is relatively unknown. Therefore, the CFAbd-Score was developed and validated following FDA recommendations for development of a PROM including focus groups, multidisciplinary CF specialists, people with CF and their families. The aim of this study was to assess effects of ETI on GI symptoms using the CFAbd-Score. Methods: Gastrointestinal symptoms were prospectively assessed in pwCF using the CFAbd-Score before and up to 26 weeks during therapy. The CFAbd-Score was also administered to a healthy control (HC) group. The one-sided questionnaire includes 28 items grouped in five domains. Data analysis included calculation of scores with a weighting tool, developed according to FDA recommendations. Results: A total of 107 pwCF attended in four CF centres in Germany and four centres in the UK completed the CFAbd-Score on at least two occasions. Results were compared to those obtained from the questionnaire of 45 HCs. Despite differences in demographics, age and proportion of pancreatic insufficiency between German and UK patients, analyses based on linear mixed-effects models at week 24 of ETI therapy revealed that estimated marginal means (EMMs) of total CFAbd-Scores significantly reduced (mean ± SE: 14.9 ± 1.2→10.6 ± 1.4; p < 0.01). Also EMMs of all five domains significantly declined ("pain" 16.3 ± 1.6→10.2 ± 2.3, "GERD" 15.8 ± 1.8→8.2 ± 1.9, "disorders of bowel movement" 20.9 ± 1.5→16.0 ± 1.7, "disorders of appetite" 7.9 ± 1.1→2.6 ± 1.1 and "quality of life impairment" 10.1 ± 1.92→3.9 ± 1.9). However, during 24 weeks, CF participants' symptoms mostly still did not reach the reference levels of HCs. Discussion: Using the CFAbd-Score, the first PROM specifically developed for assessment of CF-related abdominal symptoms, we demonstrate comprehensive improvements in GI symptoms after initiation of the highly effective modulator therapy ETI.

Surgery for nasal polyposis in cystic fibrosis

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To determine the effects of sinus surgery alone or in combination with medical treatment (non‐surgical) compared to medical treatment (non‐surgical) alone on both nasal and pulmonary function in people with cystic fibrosis diagnosed with CRS with nasal polyposis. Further, to evaluate the impact of sinus surgery (with or without medical treatment) on hospitalization rates, use of antibiotics and pulmonary exacerbation rates.

Ivacaftor restores delayed mucociliary transport caused by Pseudomonas aeruginosa-induced acquired cystic fibrosis transmembrane conductance regulator dysfunction in rabbit nasal epithelia

BACKGROUND

Abnormal chloride (Cl^- ) transport dehydrates airway surface liquid (ASL) in sinonasal epithelium leading to mucus stasis and chronic rhinosinusitis. As an experimental epithelium, rabbit tissue provides an excellent representation of human sinus disease, and the rabbit sinusitis model is both established and well suited for therapeutic interventions in vivo. Our objective in this study was to evaluate whether ivacaftor reverses the consequences of Pseudomonas aeruginosa-induced acquired cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction.

METHODS

Rabbit nasal cavities were assessed for responsiveness to ivacaftor in vivo (by nasal potential difference [NPD] assay). Rabbit nasal epithelial (RNE) cultures were incubated with an ultrafiltrate of P aeruginosa (PAO1 strain) for 4 hours and tested for acquired CFTR dysfunction. Markers of mucociliary function, including airway surface liquid depth (ASL), periciliary liquid depth (PCL), ciliary beat frequency (CBF), and mucociliary transport (MCT), were measured by micro-optical coherence tomography (μOCT) after PAO1 and/or ivacaftor incubation.

RESULTS

Ivacaftor resulted in a significant mean NPD polarization of 21.8 ± 2.1 mV, which was significantly greater than that seen in the low Cl^- control (12.9 ± 1.3; p = 0.01). PAO1 exposure induced a state of acquired CFTR dysfunction in rabbit nasal epithelium as measured by forskolin-stimulated short-circuit current (I_SC ) (control, 37.0 ± 1.1 μA/cm² ; PAO1, 24.4 ± 1.1 μA/cm² ; p < 0.001). RNE cultures exposed to PAO1 had inhibited mucociliary function, whereas coincubation with ivacaftor restored mucociliary clearance, as measured by μOCT.

CONCLUSION

In rabbit nasal epithelium, ivacaftor robustly stimulates CFTR-mediated Cl^- secretion and normalizes ASL and CBF in PAO1-induced acquired CFTR dysfunction. Preclinical testing of CFTR potentiators as therapy for P aeruginosa rabbit sinusitis is planned.

Medical interventions for chronic rhinosinusitis in cystic fibrosis

BACKGROUND

Chronic rhinosinusitis frequently occurs in people with cystic fibrosis. Several medical interventions are available for treating chronic rhinosinusitis in people with cystic fibrosis; for example, different concentrations of nasal saline irrigations, topical or oral corticosteroids, antibiotics - including nebulized antibiotics - dornase alfa and modulators of the cystic fibrosis transmembrane conductance regulator (CFTR) (such as lumacaftor, ivacaftor or tezacaftor). However, the efficacy of these interventions is unclear. This is an update of a previously published review.

OBJECTIVES

The objective of this review is to compare the effects of different medical interventions in people diagnosed with cystic fibrosis and chronic rhinosinusitis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and hand searching of journals and conference abstract books. Date of last search of trials register: 09 September 2021. We also searched ongoing trials databases, other medical databases and the reference lists of relevant articles and reviews. Date of latest additional searches: 22 November 2021.

SELECTION CRITERIA

Randomized and quasi-randomized trials of different medical interventions compared to each other or to no intervention or to placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials identified for potential inclusion in the review. We planned to conduct data collection and analysis in accordance with Cochrane methods and to independently rate the quality of the evidence for each outcome using the GRADE guidelines.

MAIN RESULTS

We identified no trials that met the pre-defined inclusion criteria. The most recent searches identified 44 new references, none of which were eligible for inclusion in the current version of this review; 12 studies are listed as excluded and one as ongoing.

AUTHORS' CONCLUSIONS

We identified no eligible trials assessing the medical interventions in people with cystic fibrosis and chronic rhinosinusitis. High-quality trials are needed which should assess the efficacy of different treatment options detailed above for managing chronic rhinosinusitis, preventing pulmonary exacerbations and improving quality of life in people with cystic fibrosis.

Understanding Cystic Fibrosis Comorbidities and Their Impact on Nutritional Management

Cystic fibrosis (CF) is a chronic, multisystem disease with multiple comorbidities that can significantly affect nutrition and quality of life. Maintaining nutritional adequacy can be challenging in people with cystic fibrosis and has been directly associated with suboptimal clinical outcomes. Comorbidities of CF can result in significantly decreased nutritional intake and intestinal absorption, as well as increased metabolic demands. It is crucial to utilize a multidisciplinary team with expertise in CF to optimize growth and nutrition, where patients with CF and their loved ones are placed in the center of the care model. Additionally, with the advent of highly effective modulators (HEMs), CF providers have begun to identify previously unrecognized nutritional issues, such as obesity. Here, we will review and summarize commonly encountered comorbidities and their nutritional impact on this unique population.

The prevalence of CFTR mutations in patients with chronic rhinosinusitis: A systematic review and meta-analysis

OBJECTIVES

Undetected cystic fibrosis transmembrane regulator (CFTR) mutations may predispose individuals to develop CRS independent of formal CF diagnosis. The objective of this study was to determine the prevalence of CFTR mutations among individuals with CRS.

DESIGN

A systematic search following PRISMA guidelines was performed. A meta-analysis was performed to calculate pooled estimates for the prevalence of any CFTR mutation and for the DF508 mutation.

SETTING AND PARTICIPANTS

The systematic search included all studies identifying adults diagnosed with CRS, with no limitation to region or publication date. Studies had to identify a sample of patients previously diagnosed with CRS but not with CF and reporting testing for the prevalence of CF or the CFTR gene mutation.

MAIN OUTCOME MEASURES

Prevalence of CFTR mutations among the general CRS population, with subgroup analysis of individuals with the dF508 mutation.

RESULTS AND CONCLUSIONS

The 6 included studies represented five countries: the United States, the UK, France, Poland and Finland. The pooled prevalence of CFTR mutations of any kind in CRS subjects without CF was 5.65% (RE 95% CI 2.99 - 10.41). The overall prevalence for the dF508 mutation was 4.22% (RE 95% CI 1.71 - 10.07). These estimates were significantly higher than the baseline estimated prevalence of CFTR carrier status of 3%-4% in the general population. However, the clinical relevance of the presence of CFTR mutations in CRS patients who have not been diagnosed with CF is currently unclear. Future studies should include sweat chloride testing as a measure of CFTR function.

Association of Quality of Life Measures and Otolaryngologic Care in Cystic Fibrosis Patients

OBJECTIVES

Appropriate management of chronic rhinosinusitis (CRS) among patients with cystic fibrosis (CF) is important in improving quality of life. Otolaryngologists play a critical role in reducing CRS symptom burden. This study seeks to evaluate the role of patient-reported quality-of-life measures in guiding interventions for CF-related sinus disease.

METHODS

We performed a prospective, cross-sectional study of 105 patients presenting to a CF-accredited clinic between July and September 2018. Demographic data and sinus surgery history were collected, in addition to Sino-Nasal Outcome Test (SNOT-22) and Questionnaire of Olfactory Disorders (QOD-NS) scores. Statistical analysis was conducted using correlation and non-parametric Mann-Whitney U tests.

RESULTS

Baseline well-care visits accounted for 71.4% of all clinical evaluations. Prior otolaryngology intervention was noted in 69 (66%) patients, where the majority of these patients (63/69; 91%) underwent endoscopic sinus surgery (ESS). Patients with a history of otolaryngology intervention had an average SNOT-22 score of 33.2 (SD = 20.6) compared to 24.9 (SD = 18.5) for patients without prior intervention (P = .048). The average QOD-NS score was 5.5 (SD = 6.4) among patients referred to otolaryngologists and 3.1 (SD = 5.7) for non-referred patients (P = .012). SNOT-22 and QOD-NS scores were modestly correlated (R of .43).

CONCLUSION

CF patients with symptoms resulting in worse quality-of-life assessments were more likely to have established coordinated care with an otolaryngologist. Further validation of the utility of SNOT-22 and QOD-NS questionnaires as care coordination metrics is necessary in the CF population.

Chronic rhinosinusitis in cystic fibrosis: a review of therapeutic options

Purpose

Chronic rhinosinusitis (CRS) is observed in almost 100% of patients with cystic fibrosis (CF). CF-related CRS treatment is extremely challenging because of the underlying genetic defect leading to its development. CRS in CF is often refractory to standard therapy, while recurrences after surgical treatment are inevitable in the majority of patients. This study provides a precise review of the current knowledge regarding possible therapeutic options for CF-related CRS.

Methods

The Medline and Web of Science databases were searched without a time limit using the terms “cystic fibrosis” in conjunction with “otorhinolaryngological manifestation”, “rhinology” and “sinusitis”.

Results

Precise guidelines for CF-induced CRS therapy are lacking due to the lack of large cohort randomized controlled trials. None of the existing therapeutic agents has already been recommended for CRS in CF. Therapy targeting the underlying genetic defect, intranasal dornase alfa administration, and topical delivery of colistin and tobramycin showed promising results in CF-related CRS therapy. Besides the potential effectiveness of nasal steroids, strong recommendations for their usage in CF have not been provided yet. Systemic corticosteroid usage is controversial due to its potential negative influence on pulmonary disease. Ibuprofen revealed some positive effects on CF-related CRS in molecular and small cohort studies. Intranasal irrigation with saline solutions could relieve sinonasal symptoms. Nasal decongestants are not recommended. Endoscopic sinus surgery is the first-line surgical option for refractory CRS. Extensive surgical approaches should be considered as they could improve long-term outcomes in CRS.

Conclusion

Further studies are warranted to establish consensus for CF-related CRS therapy.

Ivacaftor Reduces Inflammatory Mediators in Upper Airway Lining Fluid From Cystic Fibrosis Patients With a G551D Mutation: Serial Non-Invasive Home-Based Collection of Upper Airway Lining Fluid

In cystic fibrosis (CF) therapy, the recent approval of CF-transmembrane conductance regulator (CFTR) channel modulators is considered to be the major breakthrough. However, the current first-line approach based mainly on pulmonary function to measure effects of the novel therapy, tested by forced expiratory volumes in one second (FEV₁), provides restricted sensitivity to detect early structural damages. Accordingly, there is a need for new sensitive surrogate parameters. Most interestingly, these should quantify inflammation that precedes a decline of pulmonary function. We present a novel method assessing inflammatory markers in the upper airways’ epithelial lining fluid (ELF) obtained by nasal lavage (NL). In contrast to broncho-alveolar lavage, ELF sampling by NL is an attractive method due to its limited invasiveness which allows repeated analyses, even performed in a home-based setting. In a longitudinal cohort study (ClinicalTrials.gov, Identifier: NCT02311140), we assessed changes of inflammatory mediators in 259 serially obtained nasal lavages taken up to every second day before and during therapy with ivacaftor from ten CF patients carrying a G551D mutation. Patients were trained to sample NL-fluid at home, to immediately freeze and transfer chilled secretions to centers. Neutrophil Elastase, Interleukins IL-1β, IL-6 and IL-8 in NL were quantified. During 8-12 weeks of ivacaftor-treatment, median values of IL-1β and IL-6 significantly declined 2.29-fold (2.97→1.30 pg/mL), and 1.13-fold (6.48→5.72 pg/mL), respectively. In parallel, sweat tests and pulmonary function improved considerably. This is the first study assessing changes of airway inflammation on a day-to-day basis in CF patients receiving a newly administered CFTR-modulator therapy. It proves a decline of airway inflammation during ivacaftor-therapy.

LPS decreases CFTR open probability and mucociliary transport through generation of reactive oxygen species

Lipopolysaccharide (LPS) serves as the interface between gram-negative bacteria (GNB) and the innate immune response in respiratory epithelial cells (REC). Herein, we describe a novel biological role of LPS that permits GNB to persist in the respiratory tract through inducing CFTR and mucociliary dysfunction. LPS reduced cystic fibrosis transmembrane conductance regulater (CFTR)-mediated short-circuit current in mammalian REC in Ussing chambers and nearly abrogated CFTR single channel activity (defined as forskolin-activated Cl^- currents) in patch clamp studies, effects of which were blocked with toll-like receptor (TLR)-4 inhibitor. Unitary conductance and single-channel amplitude of CFTR were unaffected, but open probability and number of active channels were markedly decreased. LPS increased cytoplasmic and mitochondrial reactive oxygen species resulting in CFTR carbonylation. All effects of exposure were eliminated when reduced glutathione was added in the medium along with LPS. Functional microanatomy parameters, including mucociliary transport, in human sinonasal epithelial cells in vitro were also decreased, but restored with co-incubation with glutathione or TLR-4 inhibitor. In vivo measurements, following application of LPS in the nasal cavities showed significant decreases in transepithelial Cl^- secretion as measured by nasal potential difference (NPD) – an effect that was nullified with glutathione and TLR-4 inhibitor. These data provide definitive evidence that LPS-generated reactive intermediates downregulate CFTR function in vitro and in vivo which results in cystic fibrosis-type disease. Findings have implications for therapeutic approaches intent on stimulating Cl^- secretion and/or reducing oxidative stress to decrease the sequelae of GNB airway colonization and infection.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

Murine Model of Sinusitis Infection for Screening Antimicrobial and Immunomodulatory Therapies

The very common condition of sinusitis is characterized by persistent inflammation of the nasal cavity, which contributes to chronic rhinosinusitis and morbidity of cystic fibrosis patients. Colonization by opportunistic pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa triggers inflammation that is exacerbated by defects in the innate immune response. Pathophysiological mechanisms underlying initial colonization of the sinuses are not well established. Despite their extensive use, current murine models of acute bacterial rhinosinusitis have not improved the understanding of early disease stages due to analytical limitations. In this study, a model is described that is technically simple, allows non-invasive tracking of bacterial infection, and screening of host-responses to infection and therapies. The model was modified to investigate longer-term infection and disease progression by using a less virulent, epidemic P. aeruginosa cystic fibrosis clinical isolate LESB65. Tracking of luminescent bacteria was possible after intranasal infections, which were sustained for up to 120 h post-infection, without compromising the overall welfare of the host. Production of reactive oxidative species was associated with neutrophil localization to the site of infection in this model. Further, host-defense peptides administered by Respimat® inhaler or intranasal instillation reduced bacterial burden and impacted disease progression as well as cytokine responses associated with rhinosinusitis. Thus, future studies using this model will improve our understanding of rhinosinusitis etiology and early stage pathogenesis, and can be used to screen for the efficacy of emerging therapies pre-clinically.

Antibiotic eluting sinus stents

OBJECTIVES

Chronic rhinosinusitis (CRS) is a multifactorial disease affecting up to 16% of the United States population and disproportionately affecting the cystic fibrosis (CF) patient population. Despite treating the underlying infection, the use of systemic antibiotics has shown little efficacy in alleviation of symptom burden. This review seeks to discuss recent research on novel antibiotic eluting stent therapy in vitro and within animal models as well as the factors that contribute to its efficacy.

DATA SOURCES

PubMed literature review.

REVIEW METHODS

A review of all published literature related to antibiotic eluting sinus stents was conducted to integrate and summarize this innovative approach to chronic sinus infections.

RESULTS

Placement of the ciprofloxacin sinus stent (CSS) and ciprofloxacin-ivacaftor sinus stent (CISS) exhibited improvement in endoscopic and radiographic findings in rabbit CRS models. While the CSS showed an overall trend toward improvement in microscopic findings and a reduction in biofilm mass, there remained a significant quantity of planktonic bacteria due to antibiotic depletion from an initial burst release in the first 48 hours of stent placement. The CISS and ciprofloxacin-azithromycin sinus stents (CASSs) exhibited controlled antibiotic release over the study period leading to greatly reduced planktonic bacterial load and biofilm mass. In vitro studies indicate that CASS may be just as efficacious at reducing biofilm mass.

CONCLUSION

Antibiotic eluting sinus stents show significant promise as a novel therapeutic strategy for CRS. The CISS may have particular promise for the CF patient population by addressing both the infectious and genetic components of disease. Animal studies demonstrate significant promise for translation into human studies. Human clinical trials are warranted to determine the efficacy of antibiotic sinus stents in human patients.

LEVEL OF EVIDENCE

NA.

Chronic rhinosinusitis in patients with cystic fibrosis-Current management and new treatments

OBJECTIVES

The purpose of this article is to provide a state-of-the-art review of the literature and summarize the latest publications on medical and surgical treatment of cystic fibrosis (CF) chronic rhinosinusitis (CRS), with an emphasis on describing recent advancements in cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies.

METHODS

A comprehensive literature review was conducted utilizing the PubMed database with search phrases detailed within the body of the article. Abstracts were reviewed to include publications detailing medical, surgical, and CFTR modulating therapies for CF CRS. Findings from studies not previously reviewed and publications regarding CFTR modulators were emphasized.

RESULTS

No clear guidelines for treatment of CF CRS are available. Nasal saline rinses, topical steroids, topical antibiotics, and topical dornase alfa are reported medical therapies. Ivacaftor has some sinonasal symptomatic benefit. A new triple therapy CFTR modulator, elexacaftor/tezacaftor/ivacaftor, is capable of treating 90% of patients with CF and has shown the greatest FEV1 improvement of any CFTR modulator yet. There is no clear consensus on surgical indications or technique, though aggressive surgery in recalcitrant disease has shown some symptomatic benefit. Endoscopic sinus surgery after lung transplantation may benefit some patients in whom the sinuses serve as a reservoir for recurrent pulmonary infections by decreasing rates of bronchiolitis obliterans syndrome and improving 5 year survival.

CONCLUSION

As lifespan increases for patients with CF, further investigation into medical therapy, CFTR modulator sinonasal outcomes, and surgical technique and outcomes for CF CRS is needed.

LEVEL OF EVIDENCE

5.

TAS2R38 is a novel modifier gene in patients with cystic fibrosis

The clinical manifestation of cystic fibrosis (CF) is heterogeneous also in patients with the same cystic fibrosis transmembrane regulator (CFTR) genotype and in affected sibling pairs. Other genes, inherited independently of CFTR, may modulate the clinical manifestation and complications of patients with CF, including the severity of chronic sinonasal disease and the occurrence of chronic Pseudomonas aeruginosa colonization. The T2R38 gene encodes a taste receptor and recently its functionality was related to the occurrence of sinonasal diseases and upper respiratory infections. We assessed the T2R38 genotype in 210 patients with CF and in 95 controls, relating the genotype to the severity of sinonasal disease and to the occurrence of P. aeruginosa pulmonary colonization. The frequency of the PAV allele i.e., the allele associated with the high functionality of the T2R38 protein, was significantly lower in i) CF patients with nasal polyposis requiring surgery, especially in patients who developed the complication before 14 years of age; and ii) in CF patients with chronic pulmonary colonization by P. aeruginosa, especially in patients who were colonized before 14 years of age, than in control subjects. These data suggest a role for T2R38 as a novel modifier gene of sinonasal disease severity and of pulmonary P. aeruginosa colonization in patients with CF.

Sinonasal quality-of-life declines in cystic fibrosis patients with pulmonary exacerbations

BACKGROUND

In cystic fibrosis (CF), the relationship between chronic rhinosinusitis (CRS) and pulmonary disease is poorly understood. The purpose of this study was to evaluate the relationship between scores on the 22-item Sino-Nasal Outcome Test (SNOT-22) and CF Questionnaire-revised for adolescents and adults over 14 (CFQ-R 14+), and pulmonary function tests in 2 cohorts of CF patients: those at their baseline health and those with a pulmonary exacerbation.

METHODS

Patients >18 years old seen in a Cystic Fibrosis Foundation-accredited clinic completed the SNOT-22 and CFQ-R 14+ instruments. Patients presenting for routine care represented the baseline cohort. Patients diagnosed with a pulmonary exacerbation represented the exacerbation cohort. Average SNOT-22 and CFQ-R 14+ scores for both groups were compared using a 2-sample t test, and correlation coefficient was calculated.

RESULTS

One hundred three patients were enrolled over 3 months (30 exacerbations and 73 baseline). Patients' mean age was 32 years (56% female and 44% male). Average SNOT-22 and CFQ-R 14+ scores were significantly worse for exacerbation patients (p = 0.001 and p = 0.0003, respectively). Percent predicted forced expiratory volume in 1 second and forced vital capacity were both higher for baseline patients (p = 0.002 and p = 0.001, respectively). Average SNOT-22 score for all patients was worse than the average score for non-CF, non-CRS patients.

CONCLUSION

CF patients with pulmonary exacerbations have worse SNOT-22 and CFQ-R 14+ scores than CF patients at their baseline health. This finding suggests a temporal relationship between sinonasal and pulmonary quality of life, and that worsening of both is associated with reduced pulmonary function.

Medical interventions for chronic rhinosinusitis in cystic fibrosis

BACKGROUND

Chronic rhinosinusitis frequently occurs in people with cystic fibrosis. Several medical interventions are available for treating chronic rhinosinusitis in people with cystic fibrosis; for example, different concentrations of nasal saline irrigations, topical or oral corticosteroids, antibiotics - including nebulized antibiotics, dornase alfa and modulators of the cystic fibrosis transmembrane conductance regulator (CFTR) (such as lumacaftor, ivacaftor or tezacaftor). However, the efficacy of these interventions is unclear.

OBJECTIVES

The objective of this review is to compare the effects of different medical interventions in people diagnosed with cystic fibrosis and chronic rhinosinusitis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and hand searching of journals and conference abstract books. Date of last search of trials register: 22 May 2019.We also searched ongoing trials databases, other medical databases and the reference lists of relevant articles and reviews. Date of latest additional searches: 20 May 2019.

SELECTION CRITERIA

Randomized and quasi-randomized trials of different medical interventions compared to each other or to no intervention or to placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials identified for potential inclusion in the review. We planned to conduct data collection and analysis in accordance with Cochrane methods and to independently rate the quality of the evidence for each outcome using the GRADE guidelines.

MAIN RESULTS

We identified no trials that met the pre-defined inclusion criteria. The searches identified 47 trials, none of which were eligible for inclusion in the current version of this review.

AUTHORS' CONCLUSIONS

We identified no eligible trials assessing the medical interventions in people with cystic fibrosis and chronic rhinosinusitis. High-quality trials are needed which should assess the efficacy of different treatment options detailed above for managing chronic rhinosinusitis, preventing pulmonary exacerbations and improving quality of life in people with cystic fibrosis.

Prevalence of chronic rhinosinusitis in bronchiectasis patients suspected of ciliary dyskinesia

BACKGROUND

Mucociliary clearance is a main defense mechanism of the airway and is impaired in ciliary dyskinesia. The objective of this study was to evaluate the prevalence of chronic rhinosinusitis (CRS) and its characteristics in bronchiectasis patients suspected of harboring ciliary dyskinesia.

METHODS

Bronchiectasis patients referred to a rhinology clinic for nasal brush biopsy (NBB) were included in this study. NBB was performed using a curettage technique whereby ciliated epithelial cells were obtained from the surface of the inferior nasal turbinate. Results of transmission electron microscopy findings, primary ciliary dyskinesia (PCD) gene (35 genes) analyses (Invitae), and sinus computed tomography (CT) scans were reviewed.

RESULTS

Twenty-three patients (age, 54 ± 2.9 years) were referred for NBB between 2015 and 2018. Thirteen patients (56.5%) met the criteria for diagnosis of CRS. Nineteen patients had ciliary ultrastructural defects. The most common finding was compound cilia (n = 11, 47.8%). Five patients (21.7%) had central microtubule defects (CMD) with higher forced expiratory volume in 1 second (FEV₁ ) at the time of referral than those without CMD (CMD⁺ , 91 ± 3.7%; CMD^- , 73.5 ± 5.7%; p = 0.023). Of 15 subjects with a PCD gene panel, 67% (9 of 15) carried at least 1 gene associated with PCD. Only 1 patient reached diagnosis of PCD. Approximately 50% of non-PCD carriers had a smoking history (p < 0.05). Lund-Mackay scores did not significantly differ between PCD and non-PCD carriers (p = 0.72).

CONCLUSION

Nearly half of bronchiectasis patients referred for NBB had concurrent CRS. The presence of ciliary abnormalities was not amplified in bronchiectasis patients with CRS compared to those without CRS. Extrinsic factors may be related to ciliary structural abnormalities in non-PCD gene carriers.

Surgical Management of Chronic Rhinosinusitis in Cystic Fibrosis

Cystic fibrosis patients frequently develop chronic rhinosinusitis as a result of their propensity to form inspissated mucus and impairment of mucociliary clearance. They exhibit variable symptom burden even in the setting of positive radiographic and endoscopic findings. Current evidence suggests a positive effect of managing sinonasal disease on pulmonary health. Topical antimicrobial and mucolytic therapies are frequently required to manage the disease with surgery reserved for refractory cases. Endoscopic sinus surgery has been demonstrated to be safe and efficacious in controlling symptoms of chronic rhinosinusitis in patients with comorbid cystic fibrosis. However, the impact of surgery on pulmonary health remains an active area of investigation. In addition, a growing body of research has suggested a more extended surgical approach creating large sinonasal cavities with gravity-dependent drainage pathways, followed by adjuvant medical therapies, as an ideal strategy to optimally control disease and prevent pulmonary exacerbations. In this manuscript, we provide an up-to-date review of current evidence in the surgical management of chronic rhinosinusitis in cystic fibrosis patients.

Chronic Rhinosinusitis in Cystic Fibrosis: Diagnosis and Medical Management

Chronic rhinosinusitis (CRS) is nearly ubiquitous in patients with cystic fibrosis (CF). CF CRS is a challenging entity to define, diagnose, and treat, as patients often have severe refractory sinus disease in addition to complex medical comorbidities. The purpose of this article is to review the literature on the medical management of CF CRS and determine how to best identify, diagnose, and manage CF CRS. Ultimately, the treatment of these patients requires a multi-disciplinary approach involving the pulmonologist and otolaryngologist.

Acute and chronic non-pulmonary complications in adults with cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is a genetic disease that primarily affects the respiratory system and often leads to respiratory failure and premature death. Although pulmonary complications contribute to 85% of deaths, non-pulmonary complications are responsible for significant morbidity and mortality in adults with CF. Areas covered: This review summarizes acute and chronic non-pulmonary complications in CF patients, with emphasis on emerging complications and in the context of the current growth and aging of the CF adult population. It also addresses the potential benefits of CF transmembrane conductance regulator modulator therapy. Complications that occur after solid organ (e.g. lung and/or liver) transplantation have been excluded. The review is based on an extensive search of the available literature, using PubMed and international guidelines, and on the authors' clinical experience. Expert commentary: Acute non-pulmonary complications have been well described but should be recognized and managed carefully. Managing chronic non-pulmonary complications is an important and changing aspect of CF patient care, particularly with the emergence of novel complications in adults. Early detection of non-pulmonary complications is essential to the development of prevention and treatment strategies that aim to further improve the survival and health status of adult CF patients.

[Ageing with cystic fibrosis: Classical and emerging comorbidities in adults with cystic fibrosis]

Cystic fibrosis (CF) is a genetic disease with pulmonary involvement being predominant and often leading to respiratory failure and premature death. Non-pulmonary complications related to CF transmembrane conductance regulator (CFTR) defect are numerous and account for significant morbidity (exocrine pancreatic insufficiency, diabetes, CF-related liver disease, chronic sinusitis, osteoporosis). Improvement in patients' care led to a continuous increase in life expectancy, with a subsequent increase in the number of adult CF patients worldwide. Increased life expectancy comes with increased prevalence of CF-related comorbidities, but also with new emerging complications directly related to ageing (chronic kidney disease, cardiovascular risk factors, cancers). CFTR modulators might also contribute to modify the face of CF epidemiology and prognosis. Ageing with CF has become a challenge for CF patients and caregivers. This review summarizes classic and emerging comorbidities in the context of current growth and ageing of the CF population. It also addresses potential roles of CFTR modulators.

Emerging Role of Proteases in the Pathogenesis of Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous upper airway disease with multiple etiologies. Clinically, CRSwNP can be classified into either eosinophilic or non-eosinophilic subtypes. The eosinophilic phenotype of CRSwNP is widely thought to be highly associated with recurrence of nasal polyps or surgical failure. Epithelial cells have a crucial role in the development of Th2-biased airway diseases. Recent studies have shown that a wide range of external stimuli such as allergens and microorganisms can elicit the release of epithelial-derived Th2-driving cytokines and chemokines. Protease activity is a feature common to these multiple environmental insults and there is growing evidence for the concept that an imbalance of proteases and protease inhibitors in the epithelial barrier leads to both the initiation and maintenance of chronic eosinophilic airway inflammation. In this review, we analyze recent work on the role of proteases in the development of the sinonasal mucosal type 2 immune response with an emphasis on the molecular pathways promoting adaptive Th2 cell immunity.

Assessment of acquired mucociliary clearance defects using micro-optical coherence tomography

BACKGROUND

Dehydration of airway surface liquid (ASL) disrupts normal mucociliary clearance (MCC) in sinonasal epithelium, which may lead to chronic rhinosinusitis (CRS). Abnormal chloride (Cl^- ) transport is one such mechanism that contributes to this disorder and can be acquired secondary to environmental perturbations, such as hypoxia at the tissue surface. The objective of this study was to assess the technological feasibility of the novel micro-optical coherence tomography (μOCT) imaging technique for investigating acquired MCC defects in cultured human sinonasal epithelial (HSNE) cells.

METHODS

Primary HSNE cell cultures were subjected to a 1% oxygen environment for 12 hours to induce acquired cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction. Ion transport characteristics were assessed with pharmacologic manipulation in Ussing chambers. ASL, periciliary fluid (PCL), and ciliary beat frequency (CBF) were evaluated using μOCT.

RESULTS

Amiloride-sensitive transport (ΔI_SC ) was greater in cultures exposed to hypoxia (hypoxia: -13.2 ± 0.6 μA/cm² ; control: -6.5 ± 0.1 μA/cm² ; p < 0.01), whereas CFTR-mediated anion transport was significantly diminished (hypoxia: 28.6 ± 0.3 μA/cm² ; control: 36.2 ± 1.6 μA/cm² ; p < 0.01), consistent with acquired CFTR dysfunction and sodium hyperabsorption. Hypoxia diminished all markers of airway surface function microanatomy as observed with μOCT, including ASL (hypoxia: 5.0 ± 0.4 μm; control: 9.0 ± 0.9 μm; p < 0.01) and PCL depth (hypoxia: 2.5 ± 0.1 μm; control: 4.8 ± 0.3 μm; p < 0.01), and CBF (hypoxia: 8.7 ± 0.3 Hz; control: 10.2 ± 0.3 Hz; p < 0.01).

CONCLUSION

Hypoxia-induced defects in epithelial anion transport in HSNE led to predictable effects on markers of MCC measured with novel μOCT imaging. This imaging method represents a technological leap forward and is feasible for assessing acquired defects impacting the airway surface.