Contribution of Epithelial Cell Dysfunction to the Pathogenesis of Chronic Rhinosinusitis with Nasal Polyps

Dupilumab prevents nasal epithelial function alteration by IL-4 in vitro: Evidence for its efficacy

BACKGROUND

Chronic rhinosinusitis with nasal polyp (CRSwNP) is a typical type 2 inflammation involving interleukin (IL)-4 and IL-13. Dupilumab is a fully human monoclonal antibody targeting IL-4 receptor α subunit, thereby blocking signaling by both cytokines. Our hypothesis was that IL-4 and IL-13, by inducing a severe epithelial dysregulation, are involved in CRSwNP pathogenesis. This study aimed to evaluate the in vitro direct effect of IL-4, IL-13, and dupilumab on nasal epithelial functions.

METHODS

Nasal polyps and control mucosa from 28 patients, as well as human nasal epithelial cells (HNEC) from 35 patients with CRSwNP were used. Three major epithelial functions were investigated: the epithelial barrier function (characterized by transepithelial electrical resistance measurements and tight junction protein expression), the ciliary motion (characterized by the ciliary beating efficiency index), and wound healing (characterized by the wound repair rate) under various stimulations (IL-4, IL-13, and dupilumab). The main outcome was a significant change in epithelial functions following exposure to IL-4, IL-13, and dupilumab for 48 h in the basal media.

RESULTS

IL-4 (1, 10, and 100 ng/mL) but not IL-13 induced a significant decrease in occludin and zonula-occludens protein expression, ciliary beating efficiency, and wound repair rate in HNEC. Dupilumab (0.04 mg/mL) had no effect on HNEC and specifically restored all epithelial functions altered when cells were exposed to a 48-h IL-4 stimulation.

CONCLUSION

Dupilumab, in vitro, restored epithelial integrity by counteracting the effect of IL-4 on the epithelial barrier (increased epithelial permeability, decreased ciliary beating efficiency, and decreased wound repair rate).

CD4+ Foxp3+ Regulatory T-cells in Modulating Inflammatory Microenvironment in Chronic Rhinosinusitis with Nasal Polyps: Progress and Future Prospect

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a subtype of chronic rhinosinusitis (CRS) characterized by the presence of nasal polyps (NP) in the paranasal mucosa. Despite the complex etiology, NP is believed to result from chronic inflammation. The long-term aftermath of the type 2 response is responsible for symptoms seen in NP patients, i.e. rhinorrhea, hyposmia, and nasal obstruction. Immune cellular tolerogenic mechanisms, particularly CD4 + Foxp3 + regulatory T cells (Tregs), are crucial to curtail inflammatory responses. Current evidence suggests impaired Treg activity is the main reason underlying the compromise of self-tolerance, contributing to the onset of CRSwNP. There is compelling evidence that tumor necrosis factor 2 (TNFR2) is preferentially expressed by Tregs, and TNFR2 is able to identify the most potent suppressive subset of Tregs. Tumor necrosis factor (TNF)-TNFR2 interaction plays a decisive role in the activation and expansion of Tregs. This review summarizes current understanding of Tregs biology, focusing on the discussion of the recent advances in the study of TNF-TNFR2 axis in the upregulation of Treg function as a negative feedback mechanism in the control of chronic inflammation. The role of dysregulation of Tregs in the immunopathogenesis of CRSwNP will be analyzed. The future perspective on the harnessing Tregs-mediated self-tolerant mechanism in the management of CRSwNP will be introduced.

Association Between Dietary Factors and Chronic Sinusitis Among Korean Individuals: Insights From a Large Population-Based Study in Asia

Objective: Population-based studies on chronic sinusitis have predominantly focused on Europe and the Americas, but research on chronic sinusitis within large Asian populations remains scarce. This study aims to explore the link between dietary factors and chronic sinusitis among ethnic Koreans in Asia. Design: A cross-sectional study. Setting: Data were collected from the Korean National Health and Nutrition Examination Survey (KNHANES) in 2012. Participants: Participants in the study were included based on a doctor's diagnosis of chronic sinusitis, as determined through the ear, nose, and throat examination questionnaires. Results: Adolescents [adjusted P value (aP) < .001, adjusted odds ratio (aOR) = 1.881, 95% confidence interval (CI) = 1.380-2.564] and individuals with college and higher education (aP = .042, aOR = 1.298, 95% CI = 1.009-1.669) were more likely to develop chronic rhinosinusitis. In addition, levels of dietary fat [P = .001, interquartile range (IQR) = 34.085] and energy intake (P = .004, IQR = 981.106) were associated with an increased risk of chronic sinusitis. Moreover, high dietary inflammatory index (aP < .001, aOR = 0.547, 95% CI = 0.415-0.721), and high intake of fried pork chops (aP = .028, aOR = 1.335, 95% CI = 1.033-1.777), bread (aP = .024, aOR = 1.364, 95% CI = 1.042-1.786), and rice (aP = .021, aOR = 1.382, 95% CI = 1.051-1.818) were risk factors for chronic sinusitis, while cucumber consumption (aP < .001, aOR = 0.547, 95% CI = 0.415-0.721) was a protective factor for chronic sinusitis. Conclusion: This study revealed a significant correlation between diet and development of chronic sinusitis. These findings suggest that promoting an anti-inflammatory dietary pattern and providing guidance on healthy eating habits could help reduce the incidence of chronic sinusitis and enhance its management.

Exploring the immunopathology of type 2 inflammatory airway diseases

Significant advancements have been achieved in understanding the roles of different immune cells, as well as cytokines and chemokines, in the pathogenesis of eosinophilic airway conditions. This review examines the pathogenesis of Chronic Rhinosinusitis with Nasal Polyps (CRSwNP), marked by complex immune dysregulation, with major contributions from type 2 inflammation and dysfunctional airway epithelium. The presence of eosinophils and the role of T-cell subsets, particularly an imbalance between Treg and Th17 cells, are crucial to the disease's pathogenesis. The review also investigates the pathogenesis of eosinophilic asthma, a unique asthma subtype. It is characterized by inflammation and high eosinophil levels, with eosinophils playing a pivotal role in triggering type 2 inflammation. The immune response involves Th2 cells, eosinophils, and IgE, among others, all activated by genetic and environmental factors. The intricate interplay among these elements, chemokines, and innate lymphoid cells results in airway inflammation and hyper-responsiveness, contributing to the pathogenesis of eosinophilic asthma. Another scope of this review is the pathogenesis of Eosinophilic Granulomatosis with Polyangiitis (EGPA); a complex inflammatory disease that commonly affects the respiratory tract and small to medium-sized blood vessels. It is characterized by elevated eosinophil levels in blood and tissues. The pathogenesis involves the activation of adaptive immune responses by antigens leading to T and B cell activation and eosinophil stimulation, which causes tissue and vessel damage. On the other hand, Allergic Bronchopulmonary Aspergillosis (ABPA) is a hypersensitive response that occurs when the airways become colonized by aspergillus fungus, with the pathogenesis involving activation of Th2 immune responses, production of IgE antibodies, and eosinophilic action leading to bronchial inflammation and subsequent lung damage. This analysis scrutinizes how an imbalanced immune system contributes to these eosinophilic diseases. The understanding derived from this assessment can steer researchers toward designing new potential therapeutic targets for efficient control of these disorders.

Unraveling the Role of Epithelial Cells in the Development of Chronic Rhinosinusitis

The pathophysiology of CRS is multifactorial and complex yet needs to be completed. Recent evidence emphasizes the crucial part played by epithelial cells in the development of CRS. The epithelial cells act as physical barriers and play crucial roles in host defense, including initiating and shaping innate and adaptive immune responses. This review aims to present a comprehensive understanding of the significance of nasal epithelial cells in CRS. New research suggests that epithelial dysfunction plays a role in developing CRS through multiple mechanisms. This refers to issues with a weakened barrier function, disrupted mucociliary clearance, and irregular immune responses. When the epithelial barrier is compromised, it can lead to the passage of pathogens and allergens, triggering inflammation in the body. Furthermore, impaired mucociliary clearance can accumulate pathogens and secretions of inflammatory mediators, promoting chronic inflammation. Epithelial cells can release cytokines and chemokines, which attract and activate immune cells. This can result in an imbalanced immune response that continues to cause inflammation. The interaction between nasal epithelial cells and various immune cells leads to the production of cytokines and chemokines, which can either increase or decrease inflammation. By comprehending the role of epithelial cells in CRS, we can enhance our understanding of the disease's pathogenesis and explore new therapeutics.

Pathogenesis of chronic rhinosinusitis with nasal polyp and a prominent T2 endotype

Chronic rhinosinusitis is a heterogenous and multifactorial disease, characterized by persistent inflammation of the nose and paranasal sinuses, which causes nasal obstruction, nasal discharge, facial pain, and smell disturbance. Chronic rhinosinusitis is divided into two phenotypes: chronic rhinosinusitis with nasal polyp and chronic rhinosinusitis without nasal polyp. Nasal polyps can be associated with many inflammatory cells including eosinophil cells, neutrophil cells, plasma cells, and lymphocytes. T2 endotype is characterized by the type-2 immune response and nasal polyps are associated with eosinophilic dominant infiltration. In contrast, in the T1 and T3 endotypes, chronic rhinosinusitis can be associated with neutrophilic dominant infiltration. In addition, there are mixed types of inflammation with different proportions of eosinophils-neutrophils in chronic rhinosinusitis. In the T2 endotype, there is an increase in the production of Th2 cytokines, including interleukin-4, interleukin-5, and interleukin-13, high levels of immunoglobulin-E in polyp tissue, and eosinophilia. Stimulation of Th2 cells, type-2 innate lymphoid cells, epithelial cell damage, Staphylococcus aureus enterotoxins, and autoimmune antibodies have important roles in the enhancement of Th2 cytokines and pathogenesis of chronic rhinosinusitis with nasal polyp. Monoclonal antibodies target type-2 inflammation, decrease nasal polyp size, and improve the clinical symptoms of CRSwNP patients. The present review will focus on factors involved in the pathogenesis of chronic rhinosinusitis and its treatment.

New insights into the pathophysiology and therapeutic targets of asthma and comorbid chronic rhinosinusitis with or without nasal polyposis

Asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) or without (CRSsNP) are chronic respiratory diseases. These two disorders often co-exist based on common anatomical, immunological, histopathological, and pathophysiological basis. Usually, asthma with comorbid CRSwNP is driven by type 2 (T2) inflammation which predisposes to more severe, often intractable, disease. In the past two decades, innovative technologies and detection techniques in combination with newly introduced targeted therapies helped shape our understanding of the immunological pathways underlying inflammatory airway diseases and to further identify several distinct clinical and inflammatory subsets to enhance the development of more effective personalized treatments. Presently, a number of targeted biologics has shown clinical efficacy in patients with refractory T2 airway inflammation, including anti-IgE (omalizumab), anti-IL-5 (mepolizumab, reslizumab)/anti-IL5R (benralizumab), anti-IL-4R-α (anti-IL-4/IL-13, dupilumab), and anti-TSLP (tezepelumab). In non-type-2 endotypes, no targeted biologics have consistently shown clinical efficacy so far. Presently, multiple therapeutical targets are being explored including cytokines, membrane molecules and intracellular signalling pathways to further expand current treatment options for severe asthma with and without comorbid CRSwNP. In this review, we discuss existing biologics, those under development and share some views on new horizons.

Oncostatin M Contributes to Airway Epithelial Cell Dysfunction in Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a typical type-2 inflammation involving several cytokines and is associated with epithelial cell dysfunction. Oncostatin M (OSM) (belonging to the interleukin(IL)-6 family) could be a key driver of epithelial barrier dysfunction. Therefore, we investigated the presence of OSM and IL-6 and the expression pattern of tight junctions (TJs) in the nasal tissue of CRSwNP patients and controls using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and Western blotting. Then, their potential role in the epithelial barrier was evaluated in vitro in 27 different primary cultures of human nasal epithelial cells (HNECs) by measuring TJ expression and transepithelial electric resistance (TEER) with or without OSM or IL-6 (1, 10, and 100 ng/mL). The effect on ciliary beating efficiency was evaluated by high-speed videomicroscopy and on repair mechanisms with a wound healing model with or without OSM. OSM and IL-6 were both overexpressed, and TJ (ZO-1 and occludin) expression was decreased in the nasal polyps compared to the control mucosa. OSM (100 ng/mL) but not IL-6 induced a significant decrease in TJ expression, TEER, and ciliary beating efficiency in HNECs. After 24 h, the wound repair rate was significantly higher in OSM-stimulated HNECs at 100 ng/mL. These results suggest that OSM could become a new target for monoclonal antibodies.

New Concepts in Barrier Dysfunction in CRSwNP and Emerging Roles of Tezepelumab and Dupilumab

BACKGROUND

Epithelial barrier disturbances in CRSwNP patients play an important role in both the innate and adaptive immune responses, contributing to chronic inflammation, olfactory dysfunction, and impairments in quality of life.

OBJECTIVE

To evaluate the role of the sinonasal epithelium in disease and health, review the pathophysiology of epithelial barrier dysfunction in CRSwNP, and the immunologic targets for treatment.

METHODS

Literature review.

RESULTS

Blockade of cytokines such as thymic stromal lymphopoietin (TSLP), IL-4, and IL-13 have shown promise in barrier restoration and IL-13, specifically may be central to olfactory dysfunction.

CONCLUSION

The sinonasal epithelium plays a crucial role in the health and function of the mucosa and immune response. Increased understanding of the local immunologic dysfunction has led to several therapeutics that can potentially restore epithelial barrier function and olfaction. Real world and comparative effectiveness studies are needed.

Epidemiological Characteristics, Pathogenesis and Clinical Implications of Sinusitis in the Era of COVID-19: A Narrative Review

Sinusitis is a common condition with various forms and different etiologies. In the era of COVID-19, a large number of studies covered the association between sinusitis and COVID-19, while others reported the impact of COVID-19 on the development of acute invasive fungal rhinosinusitis (AIFR), together with the most commonly associated predisposing factors. Fungal sinusitis, particularly AIFR, can be life-threatening. It is important to dissect this association and improve current evidence and management. Therefore, we conducted this literature review to highlight the association between COVID-19 and sinusitis based on evidence from the available studies in the literature. Evidence shows that chronic sinusitis might have a negative impact on COVID-19 outcomes. However, current results are conflicting, and further studies are needed. On the other hand, COVID-19 can also cause olfactory dysfunction, which is usually temporary. In addition, we found several studies that indicated the association between COVID-19 and AIFR. The condition is usually associated with severe morbidities, as affected patients are usually immunocompromised, including those with uncontrolled diabetes, malignancy, immunosuppression, AIDS, the administration of chemotherapy and other immunosuppressive drugs, and COVID-19.

Plumping up a Cushion of Human Biowaste in Regenerative Medicine: Novel Insights into a State-of-the-Art Reserve Arsenal

Major breakthroughs and disruptive methods in disease treatment today owe their thanks to our inch by inch developing conception of the infinitive aspects of medicine since the very beginning, among which, the role of the regenerative medicine can on no account be denied, a branch of medicine dedicated to either repairing or replacing the injured or diseased cells, organs, and tissues. A novel means to accomplish such a quest is what is being called "medical biowaste", a large assortment of biological samples produced during a surgery session or as a result of physiological conditions and biological activities. The current paper accentuating several of a number of promising sources of biowaste together with their plausible applications in routine clinical practices and the confronting challenges aims at inspiring research on the existing gap between clinical and basic science to further extend our knowledge and understanding concerning the potential applications of medical biowaste.

Role of C3a as a Novel Regulator of 25(OH)D3 to 1α,25-Dihydroxyvitamin D3 Metabolism in Upper Airway Epithelial Cells

In patients with chronic rhinosinusitis with nasal polyps, primary human sinonasal epithelial cell (HSNEC) 1α-hydroxylase levels are reduced, as is their ability to metabolize 25-hydroxycholecalciferol [25(OH)D3] to its active metabolite, 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3]. In this study, we sought to identify the factor responsible for the regulation of HSNEC metabolism of 25(OH)D3, focusing on C3 and C3a. Multiple inhaled irritants trigger the release of complement components, C3 and C3a, leading to suppression of 1α-hydroxylase levels in HSNECs. Recombinant C3a was able to decrease 1α-hydroxylase and impair 25(OH)D3 to 1,25(OH)2D3 metabolism, while addition of a C3a receptor antagonist restored conversion. Conversely, 1,25(OH)2D3 suppressed Aspergillus fumigatus-induced C3 and C3a levels in HSNEC supernatant. Given the ability of 1,25(OH)2D3 to modulate LL37 in other cell types, we examined its regulation in HSNECs and relationship to C3a. 1,25(OH)2D3 stimulated the secretion of LL37, whereas A. fumigatus and C3a suppressed it. Conversely, LL37 reduced the release of C3/C3a by HSNECs. Lastly, oral steroid use and in vitro dexamethasone application both failed to increase 1α-hydroxylase or reduce C3a levels. In summary, in this article, we describe for the first time a novel relationship between complement activation and local vitamin D metabolism in airway epithelial cells. The presence of elevated C3/C3a in patients with asthma and/or chronic rhinosinusitis with nasal polyps may account for their impaired HSNEC 25(OH)D3 to 1,25(OH)2D3 metabolism and explain why they receive limited therapeutic benefit from oral vitamin D3 supplementation.

Vitamin D-mediated effects on airway innate immunity in vitro

INTRODUCTION

Vitamin D supplementation has been suggested to enhance immunity during respiratory infection season. We tested the effect of active vitamin D (calcitriol) supplementation on key airway innate immune mechanisms in vitro.

METHODS

Primary human airway epithelial cells (hAECs) grown at the air liquid interface were supplemented with 10-7 M calcitriol for 24 hours (or a time course) and their antimicrobial airway surface liquid (ASL) was tested for pH, viscoscity, and antibacterial and antiviral properties. We also tested hAEC ciliary beat frequency (CBF). Next, we assessed alterations to hAEC gene expression using RNA sequencing, and based on results, we measured neutrophil migration across hAECs.

RESULTS

Calcitriol supplementation enhanced ASL bacterial killing of Staphylococcus aureus (p = 0.02) but did not enhance its antiviral activity against 229E-CoV. It had no effect on ASL pH or viscosity at three timepoints. Lastly, it did not affect hAEC CBF or neutrophil migration, although there was a trend of enhanced migration in the presence of a neutrophil chemokine (p = 0.09). Supplementation significantly altered hAEC gene expression, primarily of AMP-related genes including CAMP and TREM1.

CONCLUSION

While vitamin D supplementation did not have effects on many airway innate immune mechanisms, it may provide a useful tool to resolve respiratory bacterial infections.

Epithelial and sensory mechanisms of nasal hyperreactivity

"Nasal hyperreactivity" is a key feature in various phenotypes of upper airway diseases, whereby reactions of the nasal epithelium to diverse chemical and physical stimuli are exacerbated. In this review, we illustrate how nasal hyperreactivity can result from at least three types of mechanisms: (1) impaired barrier function, (2) hypersensitivity to external and endogenous stimuli, and (3) potentiation of efferent systems. We describe the known molecular basis of hyperreactivity related to the functional impairment of epithelial cells and somatosensory innervation, and indicate that the thermal, chemical, and mechanical sensors determining hyperreactivity in humans remain to be identified. We delineate research directions that may provide new insights into nasal hyperreactivity associated with rhinitis/rhinosinusitis pathophysiology and therapeutics. The elucidation of the molecular mechanisms underlying nasal hyperreactivity is essential for the treatment of rhinitis according to the precepts of precision medicine.

A follow-up study of mucociliary clearance and trace element and mineral status in children with chronic rhinosinusitis before and three months after endoscopic sinus surgery

BACKGROUND

The existing data demonstrate the potential role of trace elements in nasal mucociliary clearance, although the association between trace element and mineral status and ciliary function in children with chronic rhinosinusitis is insufficiently studied. Therefore, the objective of the present study is evaluation of trace element and mineral status and mucociliary function in pediatric CRS patients before and after functional endoscopic sinus surgery.

METHODS

The present study involved 30 children with chronic rhinosinusitis without nasal polyps. During this follow-up the patients were examined preoperatively (point 0), underwent functional endoscopic sinus surgery, and were repeatedly examined at three months postoperatively (point 1). At both points the patients were subjected to quality-of-life assessment using SNOT-20 questionnaire; endoscopic and computer tomography examination of the nasal sinuses; evaluation of ciliary function and mucosal cytology using high-speed videomicroscopy; assessment of blood count and inflammatory markers; as well as analysis of trace element and mineral levels in whole blood, serum, and hair using inductively-coupled plasma mass-spectrometry.

RESULTS

The obtained data demonstrate that endoscopic sinus surgery significantly improved sinonasal pathology in children with chronic rhinosinusitis, as evidenced by significantly reduced Lund-Mackay, Lund-Kennedy, and SNOT-20 scores. At the same time, no significant improvement of ciliary functions or mucosal cytology was observed postoperatively. Trace element status assessment demonstrated that postoperative serum Zn, whole blood Mg and Cu were significantly lower as compared to preoperative values. In contrast, serum Mn and Cr, as well as whole blood Cr and hair Se were characterized by a significant increase at three months postoperatively. Multiple linear regression analysis demonstrated that serum Zn is significantly associated with the number of ciliated cells and cell viability, whereas serum Mn and whole blood Cu concentrations are inversely associated with cell viability and ciliary length, respectively. Hair Se was found to be associated with the number of neutrophils in the mucosa biopsy.

CONCLUSION

Redistribution of trace elements and minerals may at least partially mediate prolonged recovery of mucosal ciliary function in children with chronic rhinosinusitis in three months after functional sinus surgery, although the particular mechanisms of these alterations in trace element levels are to be discovered.

Dysfunction of epithelial permeability barrier induced by HMGB1 in 2.5D cultures of human epithelial cells

Airway and intestinal epithelial permeability barriers are crucial in epithelial homeostasis. High mobility group box 1 (HMGB1), increased by various stimuli, is involved in the induction of airway inflammation, as well as the pathogenesis of inflammatory bowel disease. HMGB1 enhances epithelial hyperpermeability. Two-and-a-half dimensional (2.5D) culture assays are experimentally convenient and induce cells to form a more physiological tissue architecture than 2D culture assays for molecular transfer mechanism analysis. In 2.5D culture, treatment with HMGB1 induced permeability of FITC-dextran into the lumen formed by human lung, nasal and intestinal epithelial cells. The tricellular tight junction molecule angulin-1/LSR is responsible for the epithelial permeability barrier at tricellular contacts and contributes to various human airway and intestinal inflammatory diseases. In this review, we indicate the mechanisms including angulin-1/LSR and multiple signaling in dysfunction of the epithelial permeability barrier induced by HMGB1 in 2.5D culture of human airway and intestinal epithelial cells.

Effects of HMGB1 on Tricellular Tight Junctions via TGF-β Signaling in Human Nasal Epithelial Cells

The airway epithelium of the human nasal mucosa acts as a physical barrier that protects against inhaled substances and pathogens via bicellular and tricellular tight junctions (bTJs and tTJs) including claudins, angulin-1/LSR and tricellulin. High mobility group box-1 (HMGB1) increased by TGF-β1 is involved in the induction of nasal inflammation and injury in patients with allergic rhinitis, chronic rhinosinusitis, and eosinophilic chronic rhinosinusitis. However, the detailed mechanisms by which this occurs remain unknown. In the present study, to investigate how HMGB1 affects the barrier of normal human nasal epithelial cells, 2D and 2.5D Matrigel culture of primary cultured human nasal epithelial cells were pretreated with TGF-β type I receptor kinase inhibitor EW-7197 before treatment with HMGB1. Knockdown of angulin-1/LSR downregulated the epithelial barrier. Treatment with EW-7197 decreased angulin-1/LSR and concentrated the expression at tTJs from bTJs and increased the epithelial barrier. Treatment with a binder to angulin-1/LSR angubindin-1 decreased angulin-1/LSR and the epithelial barrier. Treatment with HMGB1 decreased angulin-1/LSR and the epithelial barrier. In 2.5D Matrigel culture, treatment with HMGB1 induced permeability of FITC-dextran (FD-4) into the lumen. Pretreatment with EW-7197 prevented the effects of HMGB1. HMGB1 disrupted the angulin-1/LSR-dependent epithelial permeability barriers of HNECs via TGF-β signaling in HNECs.

Ciliary function and sinonasal mucosal cytology in pediatric patients with chronic rhinosinusitis during a year after functional endoscopic sinus surgery

BACKGROUND

The objective of the study is evaluation of ciliary function and mucosal cytology after endoscopic sinus surgery in children with chronic rhinosinusitis (CRS).

METHODOLOGY

A total of 132 children with CRS who underwent endoscopic sinus surgery, as well as 15 healthy controls were involved in the study. In this follow-up study patients were examined preoperatively, as well as 3, 6, 9, and 12 months after endoscopic sinus surgery. Assessment of ciliary function and sinonasal mucosal cytology was performed using high-speed videomicroscopy. Lund-Kennedy, Lund-Mackay, and sinonasal outcome test 20 (SNOT20) scores were also evaluated.

RESULTS

Total SNOT-20, Lund-Mackay, and Lund-Kennedy values significantly decreased after sinus surgery. In contrast, ciliary function and mucosal cytology only tended to improve after 6 months. 9 months after surgery the number of ciliated cells, ciliary beat frequency, cell viability, and ciliary length were significantly higher than preoperatively. The most significant improvement of ciliary function and cell height was observed 12 months after operation, whereas epithelial dystrophy and neutrophil infiltration were significantly reduced.

CONCLUSIONS

Substantial improvement was observed only in a year after surgery, whereas 0 to 3 months after the surgery ciliary function was severely impaired thus predisposing to recurrent sinusitis or other complications.

Estimating COVID-19 Infection and Severity Risks in Patients with Chronic Rhinosinusitis: A Korean Nationwide Cohort Study

Background

Basic studies suggest that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can affect chronic rhinosinusitis (CRS), but there is unclear real-world evidence regarding the association of underlying CRS with the risk for SARS-CoV-2 infection and severe coronavirus disease 19 (COVID-19).

Objective

We aimed to determine whether CRS is associated with increased risk for SARS-CoV-2 infection and severe COVID-19.

Methods

Altogether, 219,959 adult patients who tested for SARS-CoV-2 in South Korea from January 1 to May 15, 2020 (excluding self-referral) were identified in this nested case-control study with propensity score matching. Data on SARS-CoV-2 test results and COVID-19 worsened outcomes (ie, the need for oxygen therapy, intensive care, or mechanical ventilation, and death) were obtained from the Health Insurance Review and Assessment Service of Korea.

Results

In this matched cohort, 380 of 12,217 patients with CRS (3.1%) tested positive for SARS-CoV-2 infection, compared with 310 patients without CRS (2.5%; adjusted odds ratio = 1.22; 95% confidence interval, 1.04-1.42). Moreover, 60 of 286 COVID-19 patients with CRS (21.0%) had severe COVID-19 outcomes, compared with 38 without CRS (13.3%; adjusted odds ratio = 1.71; 95% confidence interval, 1.09-2.71). Subgroup analysis identified that CRS patients with an absence of nasal polyps, prior intranasal corticosteroid use, or nonatopic type had a greater risk for SARS-CoV-2 infection and severe COVID-19 outcomes.

Conclusions

In patients with CRS, prior intranasal corticosteroid use, the absence of nasal polyps, or nonatopic type was associated with increased risk for SARS-CoV-2 infection and severe COVID-19 in the Korean nationwide cohort. Clinicians should be cautious in determining prognosis and care for patients with CRS amid the COVID-19 pandemic.

DUOX1 in mammalian disease pathophysiology

Dual oxidase 1 (DUOX1) is a member of the protein family of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases. DUOX1 has several normal physiological, immunological, and biochemical functions in different parts of the body. Dysregulated oxidative metabolism interferes with various disease pathologies and numerous therapeutic options are based on targeting cellular redox pathways. DUOX1 forms an important enzymatic source of biological oxidants, and DUOX1 expression is frequently dysregulated in various diseases. While this review shortly addresses the biochemical and cellular properties and proposed physiological roles of DUOX1, its main purpose is to summarize the current knowledge with respect to the potential role of DUOX1 enzyme in disease pathology, especially in mammalian organisms. Although DUOX1 is normally prominently expressed in epithelial lineages, it is frequently silenced in epithelial-derived cancers by epigenetic mechanisms. While an abundance of information is available on DUOX1 transcription in different diseases, an increasing number of mechanistic studies indicate a causative relationship between DUOX1 function and disease pathophysiology. Additionally, specific functions of the DUOX1 maturation factor, DUOXA1, will also be addressed. Lastly, urgent and outstanding questions on the field of DUOX1 will be discussed that could provide valuable new diagnostic tools and novel therapeutic options.

Endoplasmic reticulum stress exacerbates inflammation in chronic rhinosinusitis with nasal polyps via the transcription factor XBP1

Endoplasmic reticulum (ER) stress results in the activation of the unfolded protein response (UPR), a process that is involved in the pathogenesis of many inflammatory diseases. However, the role of ER stress in chronic rhinosinusitis with nasal polyps (CRSwNP) has yet to be elucidated. In this study, we found that the protein expression levels of a range of ER stress regulators, including p-PERK, ATF4, ATF6 and XBP1s, were significantly increased in CRSwNP compared to controls. Importantly, the expression of ATF4 and XBP1s was positively correlated with heightened inflammation in CRSwNP. In human nasal epithelial cells, the ER stress inducer tunicamycin (TM) could potentiate Toll-like receptors (TLRs) induced proinflammatory cytokines production. Furthermore, we found that the silencing of XBP1, but not ATF4 or ATF6, abrogated the proinflammatory effect of TM. Mechanistically, ER stress did not affect the NF-κB, MAPK or IRF3 signaling pathways. However, the ER stress regulator XBP1s was able to bind directly to the promoter region of inflammatory genes to modulate gene transcription. Besides, the commensal bacteria Staphylococcus aureus and several inflammatory factors, such as IL4, IL13, IL17 and IFNγ, could induce ER stress in epithelial cells. Collectively, ER stress plays a crucial role in facilitating TLR-induced inflammation. Targeting XBP1 can inhibit the inflammatory response, thus offering a potential approach to treat CRSwNP.

Deficit in Adipose Differentiation in Mesenchymal Stem Cells Derived from Chronic Rhinosinusitis Nasal Polyps Compared to Nasal Mucosal Tissue

Chronic rhinosinusitis of the nasal mucosa is an inflammatory disease of paranasal sinuses, which causes rhinorrhea, nasal congestion, and hyposmia, and in some cases, it can result in the development of nasal polyposis. Nasal polyps are benign lobular-shaped growths that project in the nasal cavities; they originate from inflammation in the paranasal mucous membrane and are associated with a high expression of interleukins (IL)-4, IL-5, IL-13, and IgE. Polyps derive from the epithelial–mesenchymal transition of the nasal epithelium resulting in a nasal tissue remodeling. Nasal polyps from three patients with chronic rhinosinusitis as well as control non-polyp nasal mucosa were used to isolate and cultivate mesenchymal stem cells characterized as CD73⁺, CD90⁺, CD105⁺/CD14⁻, CD34⁻, and CD45⁻. Mesenchymal stem cells (MSCs) cultures were induced to differentiate toward adipocytes, where lipid droplets and adipocyte genes PPARγ2, ADIPO-Q, and FABP4 were observed in control non-polyp nasal mucosa-derived mesenchymal cells but were scarcely present in the cultures derived from the nasal polyps, where apoptosis was evident. The modulation of the response to adipogenic stimulus in polyps represents a change in the molecular response that controls the cascade required for differentiation as well as possible means to specifically target these cells, sparing the normal mucosa of the nasal sinuses.

[The role of epithelial cells in the formation and development of nasal polyps]

Nasal polyps, as a subtype of chronic sinusitis, is prone to clinical recurrence and seriously affects the quality of life of patients, but its pathogenesis is unclear. It is considered to be a chronic inflammation of the nasal-sinus mucosa under the combined action of multiple factors. Among them, nasal mucosal epithelial injury and shedding are the main pathological features. Nasal-sinus epithelial separated nasal sinuses with the outside world, is the complex natural biological barrier to resist external stimuli and the key to maintaining homeostasis in the nasal sinuses. At present, the epithelium is considered not only as a "target organ" but also as an "effector" and a central regulator of the inflammatory response. This paper reviews the role of epithelial cells in the formation and development of nasal polyps, including the epithelial cell layer were stimulated not only leads to tissue remodeling, changes in mucociliary clearance, abnormal ion channels, and proliferation and apoptosis imbalance, but also produce a series of bioactive substances in response to various internal and external stimuli.Therefore, maintaining the integrity of the structure and function of airway mucosal epithelial cells may be a new approach for clinical prevention and treatment of nasal polyps.

Effect of e-cigarettes on nasal epithelial cell growth, Ki67 expression, and pro-inflammatory cytokine secretion

OBJECTIVE

Upon use, e-cigarette aerosol comes in contact with various mucosal tissues, including the nasal epithelium, which may lead to nasal pathologies. We therefore assessed the effect of e-cigarettes on nasal epithelial cell and tissue behaviours.

METHODS

Human primary nasal epithelial cells and engineered 3D nasal mucosa tissues were exposed or not to either e-cigarette aerosol or standard cigarette smoke. We then evaluated cell viability and lactate dehydrogenase (LDH) activity. With the tissues analysed tissue structure, the expression of Ki67 proliferating marker, and the secretion of pro-inflammatory cytokines by the engineered nasal mucosa.

RESULTS

The nasal epithelial cells exposed to e-cigarettes displayed a larger cell size and a faint nucleus following exposure to e-cigarettes. This is supported by the increased levels of LDH activity following exposure to e-cigarettes, compared to that observed in the control. Tissues exposed to e-cigarette aerosol displayed a structural deregulation, with more large-sized cells, fewer Ki67-positive cells, and a reduced proliferation rate, compared to that observed in the non-exposed tissues. Cytokine measurements showed high levels of IL-6, IL-8, TNFα, and MCP-1, demonstrating that e-cigarettes activated pro-inflammatory cytokine responses.

CONCLUSION

E-cigarette aerosol showed adverse effects on nasal epithelial cells and nasal engineered mucosa tissue. These findings indicate that e-cigarettes could be a threat to nasal tissues and may impair the innate immune function of nasal epithelial cells.

Pathogenesis of chronic rhinosinusitis with nasal polyps: role of IL-6 in airway epithelial cell dysfunction

Background

Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by an alteration in airway epithelial cell functions including barrier function, wound repair mechanisms, mucociliary clearance. The mechanisms leading to epithelial cell dysfunction in nasal polyps (NPs) remain poorly understood. Our hypothesis was that among the inflammatory cytokines involved in NPs, IL-6 could alter epithelial repair mechanisms and mucociliary clearance. The aim of this study was to evaluate the in vitro effects of IL-6 on epithelial repair mechanisms in a wound repair model and on ciliary beating in primary cultures of Human Nasal Epithelial Cells (HNEC).

Methods

Primary cultures of HNEC taken from 38 patients during surgical procedures for CRSwNP were used in an in vitro model of wound healing. Effects of increasing concentrations of IL-6 (1 ng/mL, 10 ng/mL, and 100 ng/mL) and other ILs (IL-5, IL-9, IL-10) on wound closure kinetics were compared to cultures without IL-modulation. After wound closure, the differentiation process was characterized under basal conditions and after IL supplementation using cytokeratin-14, MUC5AC, and β_IV tubulin as immunomarkers of basal, mucus, and ciliated cells, respectively. The ciliated edges of primary cultures were analyzed on IL-6 modulation by digital high-speed video-microscopy to measure: ciliary beating frequency (CBF), ciliary length, relative ciliary density, metachronal wavelength and the ciliary beating efficiency index.

Results

Our results showed that: (i) IL-6 accelerated airway wound repair in vitro, with a dose–response effect whereas no effect was observed after other ILs-stimulation. After 24 h, 79% of wounded wells with IL6-100 were fully repaired, vs 46% in the IL6-10 group, 28% in the IL6-1 group and 15% in the control group; (ii) specific migration analyses of closed wound at late repair stage (Day 12) showed IL-6 had the highest migration compared with other ILs (iii) The study of the IL-6 effect on ciliary function showed that CBF and metachronal wave increased but without significant modifications of ciliary density, length of cilia and efficiency index.

Conclusion

The up-regulated epithelial cell proliferation observed in polyps could be induced by IL-6 in the case of prior epithelial damage. IL-6 could be a major cytokine in NP physiopathology.