Alterations in epithelial barrier function and host defense responses in chronic rhinosinusitis

Pathogenesis, Diagnosis, and Treatment of Infectious Rhinosinusitis

Rhinosinusitis is a common inflammatory disease of the sinonasal mucosa and paranasal sinuses. The pathogenesis of rhinosinusitis involves a variety of factors, including genetics, nasal microbiota status, infection, and environmental influences. Pathogenic microorganisms, including viruses, bacteria, and fungi, have been proven to target the cilia and/or epithelial cells of ciliated airways, which results in the impairment of mucociliary clearance, leading to epithelial cell apoptosis and the loss of epithelial barrier integrity and immune dysregulation, thereby facilitating infection. However, the mechanisms employed by pathogenic microorganisms in rhinosinusitis remain unclear. Therefore, this review describes the types of common pathogenic microorganisms that cause rhinosinusitis, including human rhinovirus, respiratory syncytial virus, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus species, etc. The damage of mucosal cilium clearance and epithelial barrier caused by surface proteins or secreted virulence factors are summarized in detail. In addition, the specific inflammatory response, mainly Type 1 immune responses (Th1) and Type 2 immune responses (Th2), induced by the entry of pathogens into the body is discussed. The conventional treatment of infectious sinusitis and emerging treatment methods including nanotechnology are also discussed in order to improve the current understanding of the types of microorganisms that cause rhinosinusitis and to help effectively select surgical and/or therapeutic interventions for precise and personalized treatment.

Does air pollutant exposure impact disease severity or outcomes in chronic rhinosinusitis?

BACKGROUND

Poor air quality increases the risk of developing chronic rhinosinusitis (CRS) and other airway diseases. However, there are limited data on air pollutants and CRS-specific disease severity. We assessed the impact of air pollutants on sinonasal-specific and general quality-of-life (QOL) measures in a multi-institutional cohort of patients with CRS.

METHODS

Participants with CRS were prospectively enrolled in a cross-sectional study and self-selected continued appropriate medical therapy or endoscopic sinus surgery (ESS). The 22-item SinoNasal Outcome Test (SNOT-22) and Medical Outcomes Study Questionnaire Short-Form 6-D (SF-6D) health utility value scores were recorded. Patient exposure to air pollutants was determined using residence zip codes. Unadjusted group differences were compared, and correlation coefficients were evaluated to identify the magnitude of bivariate association.

RESULTS

A total of 486 patients were enrolled and followed for a mean of 6.9 (standard deviation [SD] ± 2.3) months. Pollutant exposure did not significantly correlate with baseline SNOT-22 or SF-6D scores. Revision ESS was associated with higher median fine particulate matter (PM2.5; Δ = 0.12, [95% confidence interval {CI}: 0.003, 0.234]; p = 0.006) compared with primary surgery. PM2.5, PM10, and nitrogen dioxide concentrations (μg/m3) did not correlate with change in total SNOT-22 or SF-6D scores after treatment. Nevertheless, sulfur dioxide (SNOT-22: ρ = -0.121 [95% CI: -0.210, -0.030]; p = 0.007; SF-6D: ρ = 0.095 [95% CI: 0.002, 0.186]; p = 0.04) and carbon monoxide (SNOT-22: ρ = -0.141 [95% CI: -0.230, 0.050]; p = 0.002) exposure did correlate with these outcome measures.

CONCLUSION

Air pollutants may contribute, at least in part, to disease severity in CRS; future investigation is needed to further elucidate the nature of this relationship.

Leger AJ, Galor A. Living with your biome: how the bacterial microbiome impacts ocular surface health and disease

Introduction

Microbiome research has grown exponentially but the ocular surface microbiome (OSM) remains an area in need of further study. This review aims to explore its complexity, disease-related microbial changes, and immune interactions, and highlights the potential for its manipulation as a therapeutic for ocular surface diseases.

Areas Covered

We introduce the OSM by location and describe what constitutes a normal OSM. Second, we highlight aspects of the ocular immune system and discuss potential immune microbiome interactions in health and disease. Finally, we highlight how microbiome manipulation may have therapeutic potential for ocular surface diseases.

Expert Opinion

The ocular surface microbiome varies across its different regions, with a core phyla identified, but with genus variability. A few studies have linked microbiome composition to diseases like dry eye but more research is needed, including examining microbiome interactions with the host. Studies have noted that manipulating the microbiome may impact disease presentation. As such, microbiome manipulation via diet, oral and topical pre and probiotics, and hygienic measures may provide new therapeutic algorithms in ocular surface diseases.

The epithelial barrier: The gateway to allergic, autoimmune, and metabolic diseases and chronic neuropsychiatric conditions

Since the 1960 s, our health has been compromised by exposure to over 350,000 newly introduced toxic substances, contributing to the current pandemic in allergic, autoimmune and metabolic diseases. The "Epithelial Barrier Theory" postulates that these diseases are exacerbated by persistent periepithelial inflammation (epithelitis) triggered by exposure to a wide range of epithelial barrier-damaging substances as well as genetic susceptibility. The epithelial barrier serves as the body's primary physical, chemical, and immunological barrier against external stimuli. A leaky epithelial barrier facilitates the translocation of the microbiome from the surface of the afflicted tissues to interepithelial and even deeper subepithelial locations. In turn, opportunistic bacterial colonization, microbiota dysbiosis, local inflammation and impaired tissue regeneration and remodelling follow. Migration of inflammatory cells to susceptible tissues contributes to damage and inflammation, initiating and aggravating many chronic inflammatory diseases. The objective of this review is to highlight and evaluate recent studies on epithelial physiology and its role in the pathogenesis of chronic diseases in light of the epithelial barrier theory.

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.

Epithelial cell dysfunction in chronic rhinosinusitis: the epithelial-mesenchymal transition

INTRODUCTION

Epithelial-mesenchymal transition (EMT) is a type of epithelial cell dysfunction, which is widely present in the nasal mucosa of patients with chronic rhinosinusitis (CRS), especially CRS with nasal polyps, and contributes to pathogenesis of the disease. EMT is mediated via complex mechanisms associated with multiple signaling pathways.

AREAS COVERED

We have summarized the underlying mechanisms and signaling pathways promoting EMT in CRS. Strategies or drugs/agents targeting the genes and pathways related to the regulation of EMT are also discussed for their potential use in the treatment of CRS and asthma. A literature search of studies published in English from 2000 to 2023 was conducted using the PubMed database, employing CRS, EMT, signaling, mechanisms, targeting agents/drugs, as individual or combinations of search terms.

EXPERT OPINION

EMT in nasal epithelium not only leads to epithelial cell dysfunction but also plays an important role in nasal tissue remodeling in CRS. A comprehensive understanding of the mechanisms underlying EMT and the development of drugs/agents targeting these mechanisms may provide new treatment strategies for CRS.

The EphA1 and EphA2 Signaling Modulates the Epithelial Permeability in Human Sinonasal Epithelial Cells and the Rhinovirus Infection Induces Epithelial Barrier Dysfunction via EphA2 Receptor Signaling

Deficiencies in epithelial barrier integrity are involved in the pathogenesis of chronic rhinosinusitis (CRS). This study aimed to investigate the role of ephrinA1/ephA2 signaling on sinonasal epithelial permeability and rhinovirus-induced epithelial permeability. This role in the process of epithelial permeability was evaluated by stimulating ephA2 with ephrinA1 and inactivating ephA2 with ephA2 siRNA or inhibitor in cells exposed to rhinovirus infection. EphrinA1 treatment increased epithelial permeability, which was associated with decreased expression of ZO-1, ZO-2, and occludin. These effects of ephrinA1 were attenuated by blocking the action of ephA2 with ephA2 siRNA or inhibitor. Furthermore, rhinovirus infection upregulated the expression levels of ephrinA1 and ephA2, increasing epithelial permeability, which was suppressed in ephA2-deficient cells. These results suggest a novel role of ephrinA1/ephA2 signaling in epithelial barrier integrity in the sinonasal epithelium, suggesting their participation in rhinovirus-induced epithelial dysfunction.

Immunopathologic Role of Fungi in Chronic Rhinosinusitis

Airborne fungi are ubiquitous in the environment and are commonly associated with airway inflammatory diseases. The innate immune defense system eliminates most inhaled fungi. However, some influence the development of chronic rhinosinusitis. Fungal CRS is thought of as not a common disease, and its incidence increases over time. Fungi are present in CRS patients and in healthy sinonasal mucosa. Although the immunological mechanisms have not been entirely explained, CRS patients may exhibit different immune responses than healthy people against airborne fungi. Fungi can induce Th1 and Th2 immune responses. In CRS, Th2-related immune responses against fungi are associated with pattern recognition receptors in nasal epithelial cells, the production of inflammatory cytokines and chemokines from nasal epithelial cells, and interaction with innate type 2 cells, lymphocytes, and inflammatory cells. Fungi also interact with neutrophils and eosinophils and induce neutrophil extracellular traps (NETs) and eosinophil extracellular traps (EETs). NETs and EETs are associated with antifungal properties and aggravation of chronic inflammation in CRS by releasing intracellular granule proteins. Fungal and bacterial biofilms are commonly found in CRS and may support chronic and recalcitrant CRS infection. The fungal-bacterial interaction in the sinonasal mucosa could affect the survival and virulence of fungi and bacteria and host immune responses. The interaction between the mycobiome and microbiome may also influence the host immune response, impacting local inflammation and chronicity. Although the exact immunopathologic role of fungi in the pathogenesis of CRS is not completely understood, they contribute to the development of sinonasal inflammatory responses in CRS.

Prevalence and risk factors of chronic rhinosinusitis among Chinese: A systematic review and meta-analysis

Background

Chronic rhinosinusitis (CRS) can be seen in people of all ages. CRS heavily affects the quality of a patient's daily life and also causes tremendous economic burdens on patients' families and society. The prevalence of CRS in different countries varies and no systematic review of the prevalence of CRS among Chinese has been published previously. The objective of this systematic review and meta-analysis is to determine the prevalence of CRS among Chinese and to explore the main risk factors of CRS among Chinese.

Methods

Using relevant keywords, data resources including PubMed, Scopus, Web of Science, Google Scholar, Embase, Cochrane Library, Chinese National Knowledge of Infrastructure (CNKI), WANGFANG, VIP, and China Biomedical Literature database (CMB) were searched to obtain literature reporting the prevalence of and risk factors of CRS among Chinese which were clearly diagnosed with CRS from inception to 30 June 2022. The random/fixed effect model was used for meta-analysis, and the I² index was employed to assess heterogeneity among studies. All analyses were performed by using the STATA version 16.0 software. The study was registered with PROSPERO, register number. CRD42022341877.

Result

A total of 12 relevant kinds of literature were qualified for the present systematic review, including 4,033 patients. The results showed that the overall prevalence of CRS among Chinese was 10% (95%CI: 0.06-0.13, I² = 99.6%, P < 0.001). The prevalence of CRS among Chinese who lived in urban cities was 18% (95%CI: -0.07 to 0.43, I² = 99.9%, P < 0.001), which was obviously lower than the prevalence of CRS among Chinese who lived in rural areas (27%, 95%CI: -0.14 to 0.68, I² = 99.8%, P < 0.001). The prevalence of CRS among Chinese before 2010 was 23% (95%CI: -0.05 to 0.50, I² = 99.8%, P < 0.001), which was remarkably higher than the prevalence of CRS among Chinese after 2010 (7%, 95%CI: 0.05-0.09, I² = 99.0%, P < 0.001). The prevalence of CRS among Chinese who were divorced was 17% (95%CI: 0.12-0.22, I² = 0.0%, P = 0.436), while the prevalence of CRS among Chinese who were married, widowed, and unmarried was 9% (95%CI: 0.06-0.11, I² = 88.1%, P = 0.004), 9% (95%CI: 0.06-0.11, I² = 0.0%, P = 0.863), and 9% (95%CI: 0.08-0.10, I² = 0.0%, P = 0.658), respectively. The prevalence of CRS among Han and minority Chinese was 8% (95%CI: 0.07-0.10, I² = 69.6%, P = 0.070) and 12% (95%CI: 0.10-0.15, I² = 38.6%, P = 0.202), respectively. The prevalence of CRS among Chinese who was never exposed to moldy or damp environments was 8% (95%CI: 0.08-0.09, I² = 0.0%, P = 0.351), the prevalence of CRS among Chinese who was occasionally exposed to moldy or damp environments was 16% (95%CI: 0.10-0.22, I² = 78.9%, P = 0.030), and the prevalence of CRS among Chinese who was frequently or every day exposed to moldy or damp environments was up to 20% (95%CI: 0.15-0.24, I² = 0.0%, P = 0.558).

Conclusion

This meta-analysis shows that the prevalence of CRS among Chinese is at a high level. People who have some risk factors, such as occasional or frequent or everyday exposure to moldy or damp environments, have a higher prevalence of CRS. We should attach more importance to the risk factors of CRS in clinical practice and disseminate scientific information and carry out education to lower the prevalence of CRS in China.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=341877, identifier: CRD42022341877.

Histone deacetylase activity is a novel target for epithelial barrier defects in patients with eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Studies have independently indicated that eosinophils and histone deacetylases (HDACs) may compromise the integrity of the epithelial barrier in nasal polyps; however, the underlying mechanisms are not clear. In this study, we aimed to investigate the role of eosinophilia and HDACs in regulation of tight junctions (TJs) and nasal epithelial barrier integrity in chronic rhinosinusitis with nasal polyps (CRSwNP) patients.

METHODS

Expression of mRNAs and proteins of TJs and HDACs of biopsy specimens and air-liquid interface (ALI) human nasal epithelial cell cultures (HNECs) from eosinophilic and noneosinophilic CRSwNP patients and healthy controls was assessed. The ALI HNECs were also assessed for changes in transepithelial electrical resistance (TER) and paracellular flux of fluorescein isothiocyanate (FITC)-labelled dextran. Meanwhile, the assessments for the effect of HDAC inhibitor in eosinophilic nasal polyps were also conducted.

RESULTS

Decreased TER and increased paracellular flux of FITC-labelled dextran in the ALI cultures were found in both eosinophilic and noneosinophilic CRSwNP, along with irregular, patchy and reduced expression of claudin-1, 4, 7, occludin, zonula occludens (ZO)-1 and ZO-2 and increased expression of HDAC1, 9 and SIRT7 for both ALI culture cells and biopsy specimens, especially for the eosinophilic CRSwNP group. Treatment of eosinophilic CRSwNP ALI-HNECs with an HDAC inhibitor improved the TJs expression and epithelial barrier integrity.

CONCLUSIONS

Our data suggest that eosinophilia and HDACs influence epithelial barrier function in CRSwNP patients by regulating TJ protein expression. Targeting HDACs with specific inhibitors may be a potential treatment option for patients with eosinophilic CRSwNP.

Allergic Fungal Rhinosinusitis: The Role and Expectations of Biologics

Allergic fungal rhinosinusitis (AFRS) is a noninvasive subtype of chronic rhinosinusitis with nasal polyps (CRSwNP) that usually develops in immunocompetent atopic individuals and is more common in geographic regions characterized by warm temperatures and high humidity, conducive to higher environmental fungal presence. Allergic fungal rhinosinusitis usually presents with unique computed tomography findings and significant polyp burden, yet patients often report minimal sinus symptoms. Patients with AFRS often have extremely elevated serum total and fungal-specific IgE levels. Treatment almost always requires surgery, in which adjuvant medical therapy is critical to success. However, until recently the choice of adjuvant therapy has consisted primarily of either oral and/or topical steroids. Although oral corticosteroids decrease recurrence after surgery, data for the effectiveness of other adjunctive pharmacologic agents, including topical and oral antifungal agents and immunotherapy, have remained unclear and hence are not recommended in recent guidelines including the International Consensus of Allergy and Rhinology. Three biologics, omalizumab, dupilumab, and mepolizumab, have recently been approved for treating CRSwNP in general, but clinical trials to date with these biologics did not involve AFRS patients. Recently published case reports and smaller prospective studies have shown good efficacy of these biologics on the AFRS subgroup of patients. This article provides an overview of the understanding of the pathophysiology of AFRS, implications of this understanding on the possible role of biologics, and clinical reports on the use of biologics in treating AFRS. Because biologics are indicated for treating CRSwNP, follow up real-world evidence studies are needed for AFRS.

Could Chronic Rhinosinusitis Increase the Risk of Ulcerative Colitis? A Nationwide Cohort Study

Chronic rhinosinusitis (CRS) is a common chronic inflammatory disease of the sinonasal mucosa with an inflammatory or infectious etiology. Inflammatory bowel disease (IBD) causes chronic intestinal inflammation. Thus, both diseases share innate immune and epithelial barrier dysfunctions of the mucosa. However, the association between sinusitis and IBD is not well-known. We aimed to determine the association between CRS and the risk for IBDs, such as Crohn’s disease (CD) and ulcerative colitis (UC). In this long-term retrospective cohort study, 15,175 patients with CRS and 30,350 patients without CRS (comparison group) were enrolled after 1:2 propensity score matching. The incidence rates of CD and UC were 0.22 and 0.51 (1000 person-years), respectively. The adjusted hazard ratio (HR) for developing CD and UC in CRS patients was 1.01 (95% confidence interval (CI), 0.66–1.54) and 1.72 (95% CI, 1.26–2.36), respectively. Additionally, in the subgroup analysis using the CRS phenotype, the adjusted HRs of UC were significantly increased in patients with CRS without nasal polyps (adjusted HR = 1.71; 95% CI, 1.24–2.35), but not in those with CRS with nasal polyps. CRS without nasal polyps is associated with an increased incidence of UC but not CD. Therefore, clinicians should pay attention to the early detection of UC when treating patients with CRS without nasal polyps.

Environmental air pollution and chronic rhinosinusitis: A systematic review

Objective

Chronic rhinosinusitis (CRS) is a highly prevalent and burdensome disease. The pathophysiology is not fully elucidated, but environmental pollutants have been suggested to impact the inflammatory component of the disease process. This review aims to summarize the role of environmental pollution in CRS onset and disease severity.

Methods

A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were queried in August 2021. Original articles reporting on air pollution exposure in CRS were included. Other forms of sinonasal disease were excluded.

Results

Literature search produced 11,983 articles, of which 10 met inclusion criteria. Outcomes evaluated included incidence/prevalence, disease severity, quality of life, and histopathologic/microbial changes. Air pollutant exposure was associated with higher odds of CRS, particularly with particulate matter (PM) exposure. Increasing air pollution exposure was also associated with worsened disease severity and detectable histopathologic changes. Impact on quality of life was less clear.

Conclusion

Air pollution (particularly PM) is correlated with CRS incidence/prevalence and disease severity, with evidence of histopathologic changes in CRS tissue samples. Further research is warranted to better understand the mechanisms by which air pollution components may cause CRS and type 2 inflammation.

Level of Evidence

3a

Recent evidence suggests a role for air pollution in the onset and severity of CRS, most notably with relation to PM_2.5 exposure. This systematic review supports previous in vitro and in vivo models of pollution in CRS. This study further adds to the existing body of literature demonstrating the many negative health impacts of exposure to air pollution, including impacts on upper airway disease, lower airway disease, cardiac disease, and overall morbidity and mortality.

Epithelial-Cell-Derived Extracellular Vesicles in Pathophysiology of Epithelial Injury and Repair in Chronic Rhinosinusitis: Connecting Immunology in Research Lab to Biomarkers in Clinics

Epithelial barrier disruption and failure of epithelial repair by aberrant epithelial-mesenchymal transition (EMT)-induced basal cells observed in nasal mucosa of chronic rhinosinusitis (CRS) are speculated to play important roles in disease pathophysiology. Microparticles (MPs) are a type of extracellular vesicle (EV) released by budding or shedding from the plasma membrane of activated or apoptotic cells. MPs are detected in nasal lavage fluids (NLFs) and are now receiving attention as potential biomarkers to evaluate the degree of activation of immune cells and injury of structural cells in nasal mucosa of subjects with sinus disease. There are three types of epithelial-cell-derived MPs, which are defined by the expression of different epithelial specific markers on their surface: EpCAM, E-cadherin, and integrin β6 (ITGB6). When these markers are on MPs that are also carrying canonical EMT/mesenchymal markers (Snail (SNAI1); Slug (SNAI2); alpha-smooth muscle actin (αSMA, ACTA2)) or pro- and anti-coagulant molecules (tissue factor (TF); tissue plasminogen activator (tPA); plasminogen activator inhibitor-1 (PAI-1)), they provide insight as to the roles of epithelial activation for EMT or regulation of coagulation in the underlying disease. In this review, we discuss the potential of epithelial MPs as research tools to evaluate status of nasal mucosae of CRS patients in the lab, as well as biomarkers for management and treatment of CRS in the clinic.

Role of Environmental Air Pollution in Chronic Rhinosinusitis

PURPOSE OF REVIEW

Chronic rhinosinusitis (CRS) is a highly prevalent disease with large social and financial burdens. The pathophysiology is multifactorial. Environmental pollutants have been suggested to play a role in the inflammatory component of the disease process.

RECENT FINDINGS

Recent work has focused on exposure to various pollutants, primarily particulate matter (PM). Exposure to environmental pollutants leads to upregulation of inflammatory markers and ciliary dysfunction at the cellular level. Mouse models suggest a role for epithelial barrier dysfunction contributing to inflammatory changes after pollutant exposure. Clinical studies support the role of pollutants contributing to disease severity in certain populations, but the role in CRS incidence or prevalence is less clear. Research is limited by the retrospective nature of most studies. This review focuses on recent advancements in our understanding of the impact of environmental pollutants in CRS, limitations of the available data, and potential opportunities for future studies.

Mepolizumab targets multiple immune cells in aspirin-exacerbated respiratory disease

BACKGROUND

Eosinophilic asthma and nasal polyposis are hallmarks of aspirin-exacerbated respiratory disease (AERD), and IL-5 inhibition has been shown to provide therapeutic benefit. However, IL-5Rα is expressed on many cells in addition to eosinophils, and the mechanisms by which IL-5 inhibition leads to clinical benefit in eosinophilic asthma and nasal polyposis are unlikely to be due exclusively to antieosinophil effects.

OBJECTIVE

We sought to identify the mechanisms by which anti-IL-5 treatment with mepolizumab improves respiratory inflammation in AERD.

METHODS

The clinical characteristics, circulating granulocytes, nasal scraping transcripts, eosinophilic cationic protein, tryptase, and antibody levels, and urinary and nasal eicosanoid levels were measured for 18 subjects with AERD who were taking mepolizumab and compared with those of 18 matched subjects with AERD who were not taking mepolizumab.

RESULTS

Subjects taking mepolizumab had significantly fewer peripheral blood eosinophils and basophils, and those cells that remained had higher surface CRTH2 expression than did the cells from subjects not taking mepolizumab. Nasal prostaglandin F_2α, prostaglandin D₂ metabolites, leukotriene B₄, and thromboxane levels were lower in subjects taking mepolizumab, as were urinary levels of tetranor-prostaglandin D₂ and leukotriene E₄. The nasal epithelial cell transcripts that were overexpressed among subjects with AERD who were taking mepolizumab were enriched for genes involved in tight junction formation and cilium organization. Nasal and urinary prostaglandin E₂, tryptase, and antibody levels were not different between the 2 groups.

CONCLUSION

IL-5 inhibition in AERD decreases production of inflammatory eicosanoids and upregulates tight junction-associated nasal epithelial cell transcripts, likely due to decreased IL-5 signaling on tissue mast cells, eosinophils, and epithelial cells. These direct effects on multiple relevant immune cells contribute to the mechanism of benefit afforded by mepolizumab.

Revisiting the controversy: The role of fungi in chronic rhinosinusitis

In the last two decades, the development of culture-independent genomic techniques has facilitated an increased appreciation of the microbiota-immunity interactions and their role in a multitude of chronic inflammatory diseases such as chronic rhinosinusitis (CRS), asthma, inflammatory bowel disease and dermatitis. While the pathologic role of bacteria in chronic inflammatory diseases is generally accepted, the understanding of the role of fungi remains controversial. Chronic rhinosinusitis, specifically the phenotype linked to nasal polyps, represents a spectrum of chronic inflammatory diseases typically characterized by a type 2 immune response. Studies on the microbiota within sinus cavities from healthy and diseased patients have focused on the bacterial community, mainly highlighting the loss of diversity associated with sinus inflammation. Within the various CRS with nasal polyps (CRSwNP) phenotypes, allergic fungal rhinosinusitis presents an opportunity to investigate the role of fungi in chronic type 2 immune responses as well as the antifungal immune pathways designed to prevent invasive fungal diseases. In this review, we examine the spectrum of fungi-associated sinus diseases highlighting the interaction between fungal species and host immune status on disease presentation. With a focus on fungi and type 2 immune response, we highlight the current knowledge and its limitations of the sinus mycobiota along with cellular interactions and activated molecular pathways linked to fungi.

The tumor necrosis factor family molecules LIGHT and lymphotoxins in sinus mucosa of patients with chronic rhinosinusitis with or without nasal polyps

BACKGROUND

Little is known about the role of lymphotoxins (LTs) family in the sinonasal mucosa of patients with chronic rhinosinusitis (CRS). This study aims at investigating the expression of LIGHT, LTα, LTβ, and their receptors, LTβR and HVEM in normal and inflammatory sinus mucosa, and the effect of LIGHT and LTalpha1beta2 on chemokine secretion in epithelial cells, epithelial permeability, and leukocyte migration.

MATERIAL AND METHODS

The expression of LTs family in sinonasal mucosa was evaluated with real-time PCR, immunohistochemistry, and western blot. In LTβR, HVEM siRNA, or control siRNA-transfected epithelial cells treated with LIGHT or LTalpha1beta2, the expression of chemokines, the epithelial permeability, and the expression of junctional complex proteins were evaluated using real-time PCR, ELISA, western blot, confocal microscopy, and FITC-dextran. In cultured endothelial cells treated with LIGHT or LTalpha1beta2, the expression of ICAM-1 and VCAM-1, and leukocyte migration were elucidated.

RESULTS

LTs family was expressed in normal mucosa and their levels were increased in inflammatory mucosa of CRS patients. Recombinant LIGHT and LTalpha1beta2 induced chemokine secretion, increased epithelial permeability, and promoted leukocyte migration. However, the activity of LIGHT and LTalpha1beta2 was attenuated in cells transfected with LTβR and HVEM siRNA.

CONCLUSIONS

LIGHT and LTs may participate in the ongoing process of chronic inflammation, inducing chemokine secretion, leukocyte migration, and dysregulated epithelial barrier through LTβR and HVEM in sinonasal mucosa.

Paranasal sinusitis at the initiation of chemotherapy is a risk factor for invasive fungal disease in children and adolescents with cancer

BACKGROUND

The impact of paranasal sinusitis on the clinical outcome of patients with cancer remains unknown. The aim of this study was to determine whether paranasal sinusitis at the initiation of chemotherapy (SAI) affects the development of infectious complications in children and adolescents with cancer.

METHODS

A retrospective cohort analysis of patients aged 0-20 years with cancer who received chemotherapy was performed. SAI was defined as the presence of a fluid level or mucosal swelling or total opacity on sinus computed tomography examination before the initiation of chemotherapy. The primary outcome measures were the incidence of bacteremia, septic shock, and invasive fungal disease (IFD, including proven, probable, and possible cases).

RESULTS

SAI was observed in 57 (44%) of 130 enrolled patients. There were no significant differences in age, sex, and disease distribution between the patients with SAI (SAI group) and those without (non-SAI group). There was no significant difference in the 1-year cumulative incidence of bacteremia or septic shock after treatment initiation between the two groups (bacteremia, SAI group 33% vs. non-SAI group 35%, P = 0.53; septic shock, SAI group 4% vs. non-SAI group 4%, P = 0.87). The 1-year cumulative incidence of IFD was higher in the SAI group than in the non-SAI group (22% vs. 6%, P = 0.012). Cumulative incidence analysis after inverse probability of treatment weighting adjustment showed that the SAI group was more likely to develop IFD (HR: 3.5, 95% CI: 1.1-11.2, P = 0.033).

CONCLUSIONS

Our findings suggest that patients with SAI may be at higher risk for IFD during chemotherapy.

[Antimicrobial peptides and proteins in chronic rhinosinusitis]

The pathogenesis of chronic rhinosinusitis（CRS） is closely related to the interactions between the environmental stimuli and the innate defense system. A vast of defensive molecules, such as antimicrobial peptides and proteins（AMPs） could be secreted by the airway epithelial cells and submucosal glands. As an essential component of innate immune system, AMPs are associated with multiple airway disease, such as CRS, chronic obstructive pulmonary disease, bronchiectasis, allergic asthma and so on. AMPs are expressed vastly in nasal mucosa and could exert fundamental antibacterial and inflamatory regulative functions. However, the pathophysiological mechanism of AMPs in CRS is still unclear. What's more, the heterogeneity among studies is relatively high. Thus, the paper was aimed to review the potential function and inflammatory regulation of AMPs in CRS. More rigorous studies with larger samples are needed in the future, to shed light on its possible pathogeneisis mechanisms.

Reduced Expression of Antimicrobial Protein Secretory Leukoprotease Inhibitor and Clusterin in Chronic Rhinosinusitis with Nasal Polyps

Introduction

Antimicrobial peptides and proteins (AMPs) constitute the first line of defense against pathogenic microorganisms in the airway. The association between AMPs and chronic rhinosinusitis with nasal polyps (CRSwNP) requires further investigations. This study is aimed at investigating the expression and regulation of major dysregulated AMPs in the nasal mucosa of CRSwNP.

Methods

The expression of AMPs was analyzed in nasal tissue from patients with eosinophilic (E) CRSwNP and nonECRSwNP and healthy subjects using RNA sequencing. The 10 most abundant AMPs expressed differentially in CRSwNP patients were verified by real-time PCR, and of these, the expression and regulation of secretory leukoprotease inhibitor (SLPI) and clusterin (CLU) were investigated further.

Results

The 10 most abundant AMPs expressed differentially in CRSwNP compared to healthy control, regardless of subtypes, included BPIFA1, BPIFB1, BPIFB2, CLU, LTF, LYZ, and SLPI, which were downregulated, and S100A8, S100A9, and HIST1H2BC, which were upregulated. ELISA and immunofluorescence confirmed the decreased expression of SLPI and CLU levels in CRSwNP. SLPI is expressed in both nasal epithelial cells and glandular cells, whereas CLU is mainly expressed in glandular cells. AB/PAS staining further demonstrated that both SLPI and CLU were mainly produced by mucous cells in submucosal glands. Furthermore, the numbers of submucosal glands were significantly decreased in nasal polyp tissue of CRSwNP compared to nasal tissue of controls. SLPI was downregulated by TGF-β1 and IL-4 in cultured nasal tissues in vitro, while CLU expression was inhibited by TGF-β1. Glucocorticoid treatment for 2 weeks significantly increased the expression of all downregulated AMPs, but not LYZ. Additionally, budesonide significantly increased the expression of SLPI and CLU in cultured nasal tissues.

Conclusion

The expression of major antimicrobial proteins is significantly decreased in nasal tissue of CRSwNP. The expression of SLPI and CLU is correlated with the numbers of submucosal glands and regulated by inflammatory cytokines and glucocorticoids.

Adult chronic rhinosinusitis

Chronic rhinosinusitis (CRS) occurs in >10% of the adult population in Europe and the USA and can be differentiated into CRS without nasal polyps and CRS with nasal polyps (CRSwNP). Both phenotypes are characterized by a high disease burden and an overlapping spectrum of symptoms, with facial pain and loss of smell being the most differentiating. Great progress has been made in the understanding of CRS pathophysiology: from the epithelium and epithelial-mesenchymal transition to innate and adaptive immunity pathways and, finally, on the role of eosinophils and Staphylococcus aureus in the persistence of disease. Although clinical manifestations and diagnostic tools (including nasal endoscopy and imaging) have undergone major changes over the past few years, management (including pharmacotherapy, surgery and biologics) has experienced enormous progress based on the growing knowledge of key mediators in severe CRSwNP. The introduction of endotyping has led to a differentiation of 'tailored' surgical approaches, focusing on the mucosal concept in those with severe CRSwNP and on the identification of patients eligible for extended surgery and possibly biologics in the future.

Effects of Wnt signaling on epithelial to mesenchymal transition in chronic rhinosinusitis with nasal polyp

Background

Epithelial to mesenchymal transition (EMT) is associated with the pathophysiology of chronic rhinosinusitis with nasal polyp (CRSwNP). Wnt signaling is causative for EMT, whereas the mechanism in CRSwNP is not fully understood.

Objective

We sought to evaluate the role of Wnt signaling in EMT of CRSwNP using a murine nasal polyp (NP) model and human tissues.

Methods

Inflammatory markers and EMT-related molecules were evaluated in NP models using adenomatosis polyposis coli (Apc)Min/+ mice with activated Wnt signaling and NP models treated with Wnt signaling inhibitor, indocyanine green-001 (ICG-001). EMT markers and Wnt signaling-associated mediators were analysed using human sinonasal tissues from control subjects and CRSwNP patients.

Results

ApcMin/+ mice-induced NPs exhibited more frequent polypoid lesions and upregulation of Wnt-related molecules, including nuclear β-catenin, WNT3A and cyclin D1. Markers of EMT were significantly overexpressed in the ApcMin/+ NP mice (p<0.001 for E-cadherin and α-smooth muscle actin), and interleukin (IL)-17A+ cells and neutrophilic infiltration were increased in ApcMin/+ NP mice (p<0.001). Inhibition of Wnt signaling via ICG-001 resulted in significantly decreased nasal polypoid lesions (p<0.001), EMT-related markers (p=0.019 for E-cadherin and p=0.002 for vimentin) and the mRNA levels of IL-4 (p<0.001) and IL-17A (p=0.004) compared with the positive control group. Finally, nuclear β-catenin (p=0.042) was significantly increased compared with the control, and the expression levels of Wnt ligands and receptors were upregulated in human NP tissues (p=0.045 for WNT3A and p=0.042 for FZD2), suggesting increased Wnt signaling and EMT in CRSwNP.

Conclusion

Wnt signaling may contribute to the pathogenesis of NPs through EMT. Therefore, inhibition of Wnt signaling may be a potential therapeutic strategy for patients with CRSwNP.

Long-Term Clinical Follow-Up of Patients With Chronic Rhinosinusitis

Objective:

This study comprised a long-term follow-up of a cohort of patients with chronic rhinosinusitis (CRS) regarding clinical features and symptomatology.

Methods:

Data from 42 patients with CRS were available from a previous study. Forty of these patients were alive and were contacted for inclusion after approximately 10 years. Patients completed a questionnaire about disease and symptoms, and underwent a clinical examination.

Results:

Thirty-four patients (85%) responded and could be included and evaluated. For the participants in this follow-up study median length of time between initial inclusion (C1) and follow-up (C2) was 11 years (range: 8-15). In some patients the CRS shifted phenotype over time, from CRS with nasal polyposis to CRS without nasal polyposis or vice versa. The median total visual analogue score for combined sinonasal symptoms for all patients was statistically significantly reduced at follow-up. For individual patients, scores for nasal congestion, nasal discharge, facial pressure, and hyposmia were also statistically significantly reduced. The most frequently reported symptom-relieving treatments were nasal steroids and saline rinsing of the nose. Self-reported general quality of life was statistically significantly improved at C2 compared to C1.

Conclusion:

At long-term follow-up, symptoms were generally reduced and patients reported an improved quality of life. Patients can be given hope for eventual symptom relief. CRS is a chronic condition that seems to harbor the ability to alter its phenotype after several years. Topical corticosteroids and saline rinsing of the nose should be emphasized, since patients consider these treatments to be of high value.

Restraint stress increased the permeability of the nasal epithelium in BALB/c mice

Stress seems to affect the onset and evolution of diverse illnesses with an inflammatory substrate. Whether physiological or psychological, stress increases epithelial permeability. In the mucosa of the nasal cavity and upper respiratory tract, the epithelial barrier is regulated in large part by bicellular and tricellular tight junctions (bTJs and tTJs, respectively). The junctional complexes are composed of multiple membrane proteins: claudins, tight-junction-associated MARVEL proteins (TAMs: occludin, tricellulin and marvelD3), and scaffolding proteins such as ZO-1, -2 and -3. The aim of the present study was to examine the possible modification of nasal permeability and TJ protein expression in a mouse model of acute psychological stress (a 4-h immobility session). Serum corticosterone was quantified from plasma samples to verify the onset of stress. Evaluation was made of the relative concentration of key proteins in nasal mucosa by using Western blot, and of changes in permeability by analyzing FITC-Dextran leakage from the nose to the blood. Compared to the control, the stressed group showed a greater epithelial permeability to FITC-Dextran, a reduced expression of occludin and tricellulin, and an elevated expression of ZO-2 and claudin-4. This evidence points to increased paracellular flow of large molecules through an altered structure of tTJs. Apparently, the structure of bTJs remained unchanged. The current findings could provide insights into the relation of stress to the onset/exacerbation of respiratory infections and/or allergies.

Topical Vitamin D May Modulate Human Sinonasal Mucosal Responses to House Dust Mite Antigen

BACKGROUND

Respiratory epithelium is a key defense against inhaled pathogens. Vitamin D3 (VD) has been suggested to modulate airway inflammation; however, its effect on innate airway defenses, the physical barrier, mucociliary apparatus, and cytokine release remains unclear.

OBJECTIVE

To investigate the outcomes of VD application prior to challenge in an in vitro model of human sinonasal epithelium, through assessment of epithelial transepithelial resistance (TER), cilia beat frequency (CBF), and interleukin (IL)-6 release, and secondarily to determine whether topical VD is beneficial to patients with inflammatory sinonasal pathology.

METHODS

Primary human sinonasal epithelial cells from patients with eosinophilic chronic rhinosinusitis (eCRS) and healthy controls were cultured in air-liquid interface (ALI). Well-differentiated cultures from each patient were pretreated for 24 hours with 4 different VD doses. Toxicity was quantified at 24 hours in unchallenged ALI by lactate dehydrogenase (LDH) assay. Innate responses were assessed by measuring TER and CBF before and up to 24 hours after house dust mite Dermatophagoides pteronyssinus challenge. IL-6 release was evaluated 24-hour postchallenge.

RESULTS

Fifteen patients (53 ± 13.5 years, 60% females, 53% eCRS) representing 120 ALI wells were assessed. VD (0, 25, 50, 150 IU/mL) released less LDH than vehicle, indicating noncytotoxicity (0.15 ± 0.02; 0.15 ± 0.00; 0.14 ± 0.02; 0.11 ± 0.01 vs 0.17 ± 0.03, P = .004). VD increased TER for eCRS wells at 5 minutes (50 IU/mL: Δ6.76 ± 3.93 vs Δ3.87 ± 2.46, P = .04) and 24 hours (50 IU/mL: Δ0.88 ± 0.49 vs Δ0.40 ± 0.42, P = .02; 150 IU/mL: Δ1.06 ± 0.58 vs Δ0.47 ± 0.46, P = .01). CBF increased at 1 hour for eCRS wells (50 IU/mL: Δ0.62 ± 0.14 vs Δ0.41 ± 0.13, P = .001; 150 IU/ml: Δ0.60 ± 0.13 vs Δ0.38 ± 0.11, P < .001). IL-6 release was similar between normal and eCRS wells.

CONCLUSION

Topical VD supplementation in eCRS patients may be beneficial for innate epithelial defenses. VD is noncytotoxic and does not adversely affect the physical barrier, mucociliary apparatus, or IL-6 release. Further studies should clarify its potential as a therapeutic agent.

Current Concepts in the Management of Allergic Fungal Rhinosinusitis

Allergic fungal rhinosinusitis (AFRS) represents a subtype of chronic rhinosinusitis with nasal polyposis that exhibits a unique, often striking clinical presentation. Since its initial description more than a quarter century ago, a more sophisticated understanding of the pathophysiology of AFRS has been achieved and significant advancements in improving clinical outcomes made. This review focuses on the latest developments involving the pathophysiology and clinical management of this fascinating disease.

Sample collection for laboratory-based study of the nasal airway and sinuses: a research compendium

BACKGROUND

Collection of biologic samples from the nasal cavity and paranasal sinuses is of critical importance to the study of infectious or inflammatory conditions that affect both upper and lower airways. Numerous techniques for the study of ex-vivo samples exist, with specific applications, strengths, and weaknesses associated with each of them. In this compendium we summarize the available methods for collection of primary human samples and incorporate expert discussion of the pros, cons, and applications associated with each technique.

METHODS

An expert panel containing members of the American Rhinologic Society's Research and Grants Committee compiled this educational reference. Rationale for use and the potential advantages and disadvantages are discussed. Research protocols and key references are enumerated.

RESULTS

Sampling of the nasal cavity and paranasal sinuses can be achieved through a number of methods. Nonspecific sinonasal secretions may be collected via forced exhalation, nasal lavage, and nasal spray aspiration. Targeted collection of sinonasal secretions may be achieved via endoscopic placement of absorbent matrices. Nasal cytology or collection of superficial epithelium may be completed via brushing or scraping of endonasal structures. Collection of mucosal biopsies may be completed via sinonasal explant or full-thickness biopsy.

CONCLUSION

Multiple sampling techniques are available to collect biologic samples from the sinonasal cavity. These techniques differ in their ease of application, reproducibility, sample yield, and utility for different sinonasal pathologies or research goals. An appreciation of the benefits and drawbacks of each approach will allow investigators to select the techniques most appropriate for achieving research objectives.

Key role of the epithelium in chronic upper airways diseases

The respiratory epithelium of the upper airways is a first-line defence against inhaled irritants, pathogens and allergens. It ensures a physical barrier provided by apical junctions and mucociliary clearance to avoid excessive activation of the immune system. The epithelium also forms a chemical and immunological barrier, extensively equipped to protect the airways against external aggressions before the adaptive immune system is required. Under normal circumstances, the epithelium is capable of recovering rapidly after damage. This manuscript reviews these main properties of the upper airway epithelium as well as its reported impairments in chronic inflammatory diseases. The knowledge on normal epithelial functions and their dysregulation in upper airway diseases should help to design new epithelial-targeted treatments.

Current Understanding of the Acute Exacerbation of Chronic Rhinosinusitis

Background: Acute exacerbations of chronic rhinosinusitis (CRS) have been increasingly recognized as an important disease entity with a significant impact on the quality of life. There is a growing amount of research on the etiopathogenesis and management of acute exacerbations of CRS. This review aims to summarize the current literature and provide an overall understanding of acute CRS exacerbations.

Methods: A related literature review with the key terms of “chronic rhinosinusitis” and “exacerbation” was performed using PubMed.

Results: There is no consensus definition of the acute exacerbation of CRS. Impaired mucociliary clearance, atrophic rhinitis, and immunologic changes are important predisposing factors for acute CRS exacerbations. Current evidence supports the role of the transient viral infection as the initial inflammatory stimulus in the pathogenesis of acute CRS exacerbations. Secondary bacterial infection or microbial community dysbiosis within the sinonasal cavity is the main event during the acute exacerbation of CRS. Distinct changes in local and systemic immune responses during exacerbation provide new insights into the pathophysiology of CRS exacerbation. Although current guidelines suggest the use of short-term antibiotics in patients with acute CRS exacerbation for symptomatic relief, evidence-based treatment recommendations for acute CRS exacerbation are still lacking, and large-high-quality RCTs are required.

Conclusion: There have been significant advances in understanding the etiology and immunological feathers of acute CRS exacerbation. Nevertheless, consensus definition, diagnostic criterion, biomarkers to differentiate acute CRS exacerbation from CRS, assessment of disease severity, and evidence-based treatment options for acute CRS exacerbation are still lacking.

Multiple gene expression profiling suggests epithelial dysfunction in polypoid chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogeneous inflammatory disorder resulting from a complex gene-environment interaction. Although its aetiology remains elusive, numerous studies reported gene expression alterations of factors apparently implicated in all aspects of the inflammatory response. However, most investigations are limited, unconfirmed analyses of a single gene. Moreover, studies concerning multiple gene expression analyses, usually on inflammatory mediators (e.g. cytokines), show contrasting outcomes in part due to use of heterogeneous samples or methodologies with limited power. In this scenario, our goal was to simultaneously evaluate the expression of a panel of selected genes (AQP5, MUC5AC, CAV1, LTF, COX2, PGDS, TNFα, TGFβ1, MGB1) potentially involved in CRS inflammatory mechanisms. While most of the samples collected were excluded from the analysis because of poor quality RNA, we were able to demonstrate statistically significant downregulation of the AQP5, CAV1, LTF, MGB1 genes in a specific subset of polypoid CRS (patients without typical comorbidities), which might suggest relevant underlying epithelial dysfunction. Further studies are needed to enrich our knowledge on the pathogenesis of CRS. Forthcoming approaches might utilise next-generation RNA sequencing and comprehensive bioinformatics analyses to better characterise the transcriptome profiles of CRS endotypes.

Mir-142-3p Regulates Inflammatory Response by Contributing to Increased TNF-α in Chronic Rhinosinusitis With Nasal Polyposis

Objective:

Previous studies suggested that microRNAs played an important role in the progression of inflammation and remodeling of chronic rhinosinusitis with nasal polyposis. However, the abnormal expression of microRNAs and regulation cytokine expression in nasal polyposis are not clear.

Method:

The miR-142-3p and tumor necrosis factor α (TNF-α) expression levels in chronic rhinosinusitis with nasal polyposis were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The miR-142-3p and TNF-α levels in human nasal epithelial cells (HNEpC) after stimulation by lipopolysaccharide (LPS) were detected by qRT-PCR. Moreover, HNEpCs were transfected by miR-142-3p mimics or inhibitor or cotransfected with si-TNF-α to evaluate the regulation of miR-142-3p on TNF-α which affects the production of inflammatory factors.

Results:

The miR-142-3p and TNF-α were significantly higher in nasal mucosa of chronic rhinosinusitis with polyps patients compared to normal human. MiR-142-3p and TNF-α expression levels were increased after LPS stimulation in a dose- and time-dependent manner. Knockdown of miR-142-3p in HNEpCs downregulated TNF-α expression at both messenger RNA and protein levels.

Conclusions:

It is indicated that miR-142-3p may participate in the regulation of the body’s inflammatory response through the LPS-TLR-TNF-α signaling pathway in chronic rhinosinusitis with nasal polyposis.

The PI3K-Akt-HIF-1α Pathway Reducing Nasal Airway Inflammation and Remodeling in Nasal Polyposis

OBJECTIVE

Previous studies suggested that hypoxia-inducible factor-1α (HIF-1α) plays an important role in the progression of inflammation and remodeling of chronic rhinosinusitis with nasal polyposis. However, the molecule mechanisms of HIF-1α activation and regulation of cytokine expressions, such as interleukin (IL) 25 and IL-17RB, in nasal polyposis are not clear.

METHOD

The IL-25 and IL-17RB levels in human nasal epithelial cells after stimulation by lipopolysaccharide (LPS) were detected by enzyme-linked immunosorbent assay method, and the proteins of HIF-1α and p-Akt were detected by Western blot method. Moreover, we evaluated the cytokine levels in the nasal mucosa of a murine model of nasal polyposis.

RESULTS

The levels of IL-25 and IL-17RB showed dose- and time-dependent release in response to LPS stimulation. The proteins of HIF-1α and p-Akt were both increased significantly after LPS stimulation. After inhibition of PI3K/Akt pathway by PI3K inhibitor LY294002, the levels of IL-25 and IL-17RB and HIF-1α were decreased by LPS stimulation.

CONCLUSIONS

Inhibition of PI3K or HIF-1α pathway could significantly reduce growth factor production and decrease nasal inflammation. The HIF-1α pathway could be a novel therapeutic approach for reducing nasal airway inflammation and remodeling in nasal polyposis.

Increased expression of interleukin 36 in chronic rhinosinusitis and its contribution to chemokine secretion and increased epithelial permeability

BACKGROUND

IL-36 family, a recently reported member of the IL-1 cytokine family, plays an essential role in nonspecific innate immune response to infection. This study aims at investigating the expression of IL-36 family members (α, β, and γ) in normal and inflammatory sinus mucosa of patients with chronic rhinosinusitis (CRS), their effects on chemokine secretion and on the barrier function of epithelial and endothelial cells, and the effect of Toll-like receptors on the expression of IL-36 in epithelial cells.

MATERIAL AND METHODS

The expression of IL-36 family in normal and inflammatory sinus mucosa, the production of chemokines or the expression levels of IL-36 family in epithelial cells treated with IL-36 family members or stimulated with TLR3, TLR4, TLR5, or TLR7/8 agonists were measured with real time PCR, ELISA, immunohistochemistry, or Western blot. The epithelial and endothelial permeability, and transendothelial leukocyte migration were investigated using cultured epithelial and endothelial cells.

RESULTS

IL-36α, IL-36β, and IL-36γ were localized in epithelial cells of sinonasal mucosa. Their levels increased in inflammatory mucosa of CRS patients and are up-regulated by TLR3, TLR4, or TLR5 agonists. IL-36α, or IL-36γ induced CXCL1, CXCL2, and CXCL3 production. Epithelial and endothelial permeability, transendothelial leukocyte migration were increased in cells treated with IL-36α, IL-36β, or IL-36γ.

CONCLUSIONS

These results suggest that IL-36α, IL-36β, and IL-36γ localized in superficial epithelium may act as a responder to microbial and nonmicrobial elements through TLR and subsequently produce CXC chemokines, playing an interplay between innate and adaptive immune response.

Diverse phenotypes and endotypes of fungus balls caused by mixed bacterial colonization in chronic rhinosinusitis

BACKGROUND

The pathogenic roles of fungus and bacteria in chronic rhinosinusitis (CRS) remain unclear. Recently, we described the bacterial ball, which is distinct from the fungus ball, as an unusual phenotype of bacterial infection. In this study, we investigated the clinical, histopathologic, and immunologic characteristics of sinonasal microorganic materials, including fungus ball and bacterial ball.

METHODS

In this study, we enrolled 80 CRS patients with sinonasal microorganic materials and 10 control subjects who underwent skull base surgery or endoscopic dacryocystorhinostomy and had no signs or symptoms of nasal inflammation. All specimens were stained with hematoxylin-eosin, Gomori-methenamine-silver, and Gram stain to identify fungal organisms and Gram-positive/negative bacterial colonies. The expression of tumor necrosis factor (TNF)-α; interleukin (IL)-1β; S100A7; S100A8/A9; and short, palate, lung, and nasal epithelial clone 1 (SPLUNC1) were evaluated by enzyme-linked immunosorbent assay using sinus lavage fluid.

RESULTS

We histologically classified sinonasal microorganic materials into the following 4 groups: fungus ball (n = 45); bacterial ball (n = 6); mixed ball (formed by a mixture of fungus and bacteria, n = 27); and double ball (formed by separate fungal and bacterial balls, n = 2). Compared with the fungus ball, the mixed ball was more frequently detected in immunocompromised patients (p < 0.0001). In addition, TNF-α expression was significantly higher in fungus and mixed balls than in control, whereas the mixed ball showed higher expression of IL-1β compared with the fungus ball. Moreover, the expression of S100A7 and S100A8/A9 protein in the mixed ball was significantly decreased when compared with the fungus ball, whereas there was no significant difference in SPLUNC1 expression between fungus and mixed balls.

CONCLUSION

Our findings suggest that fungal and bacterial interactions are diverse in CRS. Specifically, the mixed ball is prevalent in CRS with an immunocompromised state and it may decrease epithelial barrier function.

Responses of Well-differentiated Human Sinonasal Epithelial Cells to Allergen Exposure and Environmental Pollution in Chronic Rhinosinusitis

Background

Evidence suggests that intrinsic cell dysfunction leads to dysregulated immune responses to environmental triggers in chronic rhinosinusitis (CRS). Although epidemiological and in vivo studies support this theory, in vitro studies are lacking.

Methods

Epithelial cells from human sinonasal mucosa were cultured using an air–liquid interface culture model producing a well-differentiated phenotype. Specimens were characterized as chronic rhinosinusitis with (CRSwNP) or without (CRSsNP) nasal polyps and healthy control mucosa. Culture wells were exposed to house dust mite (HDM), diesel exhaust particles (DPM), or a combination (HDM + DPM) over 24 hours and responses in the 3 groups compared. Ciliary beat frequency (CBF) and transepithelial electrical resistance (TEER) were measured to assess mucociliary and barrier function, respectively. Interleukin-6 (IL-6) and 33 (IL-33) were measured after 24 hours. Results following challenge testing are expressed as fold change from baseline.

Results

Baseline CBF was lower in CRSsNP compared with control (5.27 ± 0.51 Hz vs 5.88 ± 1.22 Hz, P = .003). HDM significantly reduced CBF and TEER in the CRSwNP group compared with its vehicle (CBF: 0.55 ± 0.25 vs 1.03 ± 0.22, P < .001; TEER: 0.54 [0.13] Ω cm2 vs 0.93 [0.5] Ω cm2, P = .001). In CRSwNP and CRSsNP, HDM induced an increase in IL-6 compared with its vehicle (CRSwNP: 81.11 [67.19] pg/mL vs 3.15 [44.64] pg/mL, P = .016; CRSsNP: 321.46 [182.04] pg/mL vs 21.54 [53.93] pg/mL, P = .004). Results are expressed as median (interquartile range) and in IL-33 in CRswNP (84.04 [69.96] pg/mL vs 16.62 [20.19] pg/mL, P = .025). Exposure to DPM did not affect CBF, TEER, and cytokine release in all groups.

Conclusion

CRSwNP and CRSsNP cells exhibit altered responses particularly to HDM even after they have been removed from their host and cultured in vitro, suggesting an intrinsic cell dysfunction of the upper airway epithelium.

Epithelial physical barrier defects in chronic rhinosinusitis

INTRODUCTION

Chronic rhinosinusitis (CRS) is a common upper airway disease with a prevalence of greater than 10% of the general population. Although the pathogenesis of CRS remains poorly understood, there is growing evidence indicating that epithelial physical barrier defects play an important role in CRS pathogenesis. Areas covered: Epithelial physical barriers are maintained by various intercellular junctions, especially tight junctions (TJs). Recent studies suggest that the expression of TJ molecules and epithelial barrier function in human nasal epithelium are modulated by various internal and external factors. This review summarizes recent advances regarding the structure, function, and regulating mechanisms of the epithelial physical barrier in the context of CRS. Expert opinion: Available data indicate that epithelial physical barrier defects in CRS can result from inhaled allergens, microbial or virus infections, cytokines, hypoxia, or zinc deficiency, among other causes. Several genes/molecules, such as SPINK5, S100A7, S100A8/9, PCDH1, NDRG1, SPRR, and p63 are involved in modulating the physical barrier function in the context of CRS. The exact mechanisms and molecular pathways that lead to these barrier defects, however, require additional study. Additional work is necessary to further explore the epithelial physical barrier function in normal and pathologic sinonasal mucosa.

FcγRIII stimulation breaks the tolerance of human nasal epithelial cells to bacteria through cross-talk with TLR4

The nasal cavity displays immune tolerance to commensal bacteria under homeostatic conditions, which is rapidly converted to a pro-inflammatory response upon infection. Yet, the factors that control this conversion are still largely unknown. Here, we provide evidence that Fc gamma receptor III (FcγRIII) stimulation breaks immune tolerance to bacteria in the human nasal cavity through activation of nasal epithelial cells, which are the first line of defense against invading microbes. While under steady-state conditions human nasal epithelial cells were completely non-responsive to Gram-negative bacteria P. aeruginosa or TLR4 ligand LPS, IgG opsonization of bacteria, as occurs upon infection, strongly induced production of pro-inflammatory agents such as IL-6 and IL-8. This breaking of tolerance to bacteria was completely dependent on FcγRIII, which amplified cytokine gene transcription through cross-talk with TLR4. In addition, we identified that epithelial cells from patients suffering from chronic rhinosinusitis with nasal polyps do not display LPS tolerance, thereby providing an explanation for the disturbed host defense responses of these patients. Taken together, these data are the first to identify FcγR expression on nasal epithelial cells, as well as to identify its important role in controlling the balance between tolerance and inflammation in the nasal cavity.

Pseudomonas aeruginosa Exoprotein-Induced Barrier Disruption Correlates With Elastase Activity and Marks Chronic Rhinosinusitis Severity

Background:Pseudomonas aeruginosa causes severe chronic respiratory diseases and is associated with recalcitrant chronic rhinosinusitis (CRS). P. aeruginosa exoproteins contain virulence factors and play important roles in the pathogenicity of P. aeruginosa, however their role in CRS pathophysiology remains unknown.

Methods: We isolated P. aeruginosa clinical isolates (CIs) and obtained clinical information from 21 CRS patients. Elastase activity of the CIs was measured at different phases of growth. Primary human nasal epithelial cells (HNECs) were cultured at air-liquid interface (ALI) and challenged with P. aeruginosa exoproteins or purified elastase, followed by measuring Transepithelial Electrical Resistance (TEER), permeability of FITC-dextrans, western blot, and immunofluorescence.

Results: 14/21 CIs had a significant increase in elastase activity in stationary phase of growth. There was a highly significant strong correlation between the in vitro elastase activity of P. aeruginosa CIs with mucosal barrier disruption evidenced by increased permeability of FITC-dextrans (r = 0.95, p = 0.0004) and decreased TEER (r = −0.9333, P < 0.01) after 4 h of challenge. Western blot showed a significant degradation of ZO-1, Occludin and β-actin in relation to the elastase activity of the exoproteins. There was a highly significant correlation between the in vitro elastase activity of P. aeruginosa CIs and CRS disease severity (for log phase, r = 0.5631, p = 0.0097; for stationary phase, r = 0.66, p = 0.0013) assessed by CT imaging of the paranasal sinuses.

Conclusion: Our results implicate P. aeruginosa exoproteins as playing a major role in the pathophysiology of P. aeruginosa associated CRS by severely compromising mucosal barrier structure and function.

Bacteriotherapy with Streptococcus salivarius 24SMB and Streptococcus oralis 89a oral spray for children with recurrent streptococcal pharyngotonsillitis: a randomized placebo-controlled clinical study

PURPOSE

Group A beta-hemolytic Streptococcus (GABHS) causes a recurrent acute pharyngotonsillitis (RAPT) in children. Moreover, the repeated use of antibiotics contributes to its resistance. However, S. Salivarius 24SMB and S. oralis 89a were effective probiotics in other infections. Thus, we decided to evaluate this combination efficacy compared to placebo in RAPT.

METHODS

Patients with microbiologically confirmed GABHS were enrolled in this randomized, placebo-controlled trial. They received the aforementioned combination or placebo as an oral spray. We investigated episodes of frequency and duration, need for antibiotics, school days lost, the treatment impact on life quality, treatment compliance and side effects during a 90-day treatment and a 6-month follow-up.

RESULTS

We included 41 patients in each group. The mean number of GABHS infection was significantly lower during both study periods for the two groups. However, our treatment group showed a lower rate. Moreover, the probiotic group had a lower mean number and a shorter median duration of GABHS episodes during both study periods than controls. Furthermore, the mean duration of antibiotic treatment was lower in the probiotic group during the 90-day and 6-month follow-up periods. Similarly, patients in the probiotic group showed a significantly lower mean number of absence days from school but higher EQ-VAS score. Indeed, all patients included were compliant to treatment.

CONCLUSIONS

We identified potential probiotics, possessing desirable features against GABHS pharyngotonsillitis. Our findings represent the first evidence which throws the light on using these probiotics that can reduce antibiotics use which did not have efficient results regarding recurrence.

Comparison of Subtyping Approaches and the Underlying Drivers of Microbial Signatures for Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a major human health problem that significantly reduces quality of life. While various microbes have been implicated, there is no clear understanding of the role they play in CRS pathogenesis. Another equally important observation made for CRS patients is that the epithelial barrier in the sinonasal cavity is defective. Finding a robust approach to subtype CRS patients would be the first step toward unravelling the pathogenesis of this heterogeneous condition. Previous work has explored stratification based on the clinical presentation of the disease (with or without polyps), inflammatory markers, pathology, or microbial composition. Comparisons between the different stratification approaches used in these studies have not been possible due to the different cohorts, analytical methods, or sample sites used. In this study, two approaches for subtyping CRS patients were compared, and the underlying drivers of the heterogeneity in CRS were also explored.

Chronic rhinosinusitis (CRS) is a heterogeneous condition characterized by persistent sinus inflammation and microbial dysbiosis. This study aimed to identify clinically relevant subgroups of CRS patients based on distinct microbial signatures, with a comparison to the commonly used phenotypic subgrouping approach. The underlying drivers of these distinct microbial clusters were also investigated, together with associations with epithelial barrier integrity. Sinus biopsy specimens were collected from CRS patients (n = 23) and disease controls (n = 8). The expression of 42 tight junction genes was evaluated using quantitative PCR together with microbiota analysis and immunohistochemistry for measuring mucosal integrity and inflammation. CRS patients clustered into two distinct microbial subgroups using probabilistic modelling Dirichlet (DC) multinomial mixtures. DC1 exhibited significantly reduced bacterial diversity and increased dispersion and was dominated by Pseudomonas, Haemophilus, and Achromobacter. DC2 had significantly elevated B cells and incidences of nasal polyps and higher numbers of Anaerococcus, Megasphaera, Prevotella, Atopobium, and Propionibacterium. In addition, each DC exhibited distinct tight junction gene and protein expression profiles compared with those of controls. Stratifying CRS patients based on clinical phenotypic subtypes (absence or presence of nasal polyps [CRSsNP or CRSwNP, respectively] or with cystic fibrosis [CRSwCF]) accounted for a larger proportion of the variation in the microbial data set than with DC groupings. However, no significant differences between CRSsNP and CRSwNP cohorts were observed for inflammatory markers, beta-dispersion, and alpha-diversity measures. In conclusion, both approaches used for stratifying CRS patients had benefits and pitfalls, but DC clustering provided greater resolution when studying tight junction impairment. Future studies in CRS should give careful consideration to the patient subtyping approach used.

IMPORTANCE Chronic rhinosinusitis (CRS) is a major human health problem that significantly reduces quality of life. While various microbes have been implicated, there is no clear understanding of the role they play in CRS pathogenesis. Another equally important observation made for CRS patients is that the epithelial barrier in the sinonasal cavity is defective. Finding a robust approach to subtype CRS patients would be the first step toward unravelling the pathogenesis of this heterogeneous condition. Previous work has explored stratification based on the clinical presentation of the disease (with or without polyps), inflammatory markers, pathology, or microbial composition. Comparisons between the different stratification approaches used in these studies have not been possible due to the different cohorts, analytical methods, or sample sites used. In this study, two approaches for subtyping CRS patients were compared, and the underlying drivers of the heterogeneity in CRS were also explored.

In-Depth, Proteomic Analysis of Nasal Secretions from Patients With Chronic Rhinosinusitis and Nasal Polyps

Purpose

Chronic rhinosinusitis (CRS) is a complex immunological condition, and novel experimental modalities are required to explore various clinical and pathophysiological endotypes; mere evaluation of nasal polyp (NP) status is inadequate. Therefore, we collected patient nasal secretions on filter paper and characterized the proteomes.

Methods

We performed liquid chromatography-mass spectrometry (MS)/MS in the data-dependent acquisition (DDA) and data-independent acquisition (DIA) modes. Nasal secretions were collected from 10 controls, 10 CRS without NPs (CRSsNP) and 10 CRS with NPs (CRSwNP). We performed Orbitrap MS-based proteomic analysis in the DDA (5 controls, 5 CRSsNP and 5 CRSwNP) and the DIA (5 controls, 5 CRSsNP and 5 CRSwNP) modes, followed by a statistical analysis and a hierarchical clustering to identify differentially expressed proteins in the 3 groups.

Results

We identified 2,020 proteins in nasal secretions. Canonical pathway analysis and gene ontology (GO) evaluation revealed that interleukin (IL)-7, IL-9, IL-17A and IL-22 signaling and neutrophil-mediated immune responses like neutrophil degranulation and activation were significantly increased in CRSwNP compared to control. The GO terms related to the iron ion metabolism that may be associated with CRS and NP development.

Conclusions

Collection of nasal secretions on the filter paper is a practical and non-invasive method for in-depth study of nasal proteomics. Our proteomic signatures also support that Asian NPs could be characterized as non-eosinophilic inflammation features. Therefore, the proteomic profiling of nasal secretions from CRS patients may enhance our understanding of CRS endotypes.

Alternaria-induced barrier dysfunction of nasal epithelial cells: role of serine protease and reactive oxygen species

BACKGROUND

Upper airway barrier dysfunction has been associated with chronic rhinosinusitis and allergic rhinitis. Alternaria is commonly found in nasal secretion and plays a role in the pathogenesis of airway diseases. The aim of this study was to investigate the effects of Alternaria on the junctional complex of nasal epithelial cells.

METHODS

Air-liquid interface nasal epithelial cultures from the inferior turbinate of septal surgery patients were stimulated with Alternaria alternate. Production of intracellular reactive oxygen species (ROS) and transepithelial resistance (TER) was measured. The expression of tight junction (TJ) and adherens junction (AJ) molecules was determined using real-time reverse transcriptase-polymerase chain reaction, Western blot analysis, and confocal microscopy. Protease activity in Alternaria was determined using protease inhibitors and heat inactivation.

RESULTS

Alternaria enhanced the production of ROS and reduced the TER. Alternaria decreased the messenger RNA and protein expression of TJs (zonula occludens-1, occludin, and claudin-1), but did not influence the AJ molecule. When Alternaria was pretreated with serine protease inhibitor and heat inactivation, ROS, TER, and TJ molecule expression returned to their nonstimulated levels.

CONCLUSION

Serine protease in Alternaria altered nasal epithelial barrier function. Intracellular ROS induced by Alternaria may influence the barrier function of nasal epithelial cells and enhance the inflammatory process of nasal mucosa.

Eosinophil Extracellular Traps and Inflammatory Pathologies-Untangling the Web!

Eosinophils are an enigmatic white blood cell, whose immune functions are still under intense investigation. Classically, the eosinophil was considered to fulfill a protective role against parasitic infections, primarily large multicellular helminths. Although eosinophils are predominantly associated with parasite infections, evidence of a role for eosinophils in mediating immunity against bacterial, viral, and fungal infections has been recently reported. Among the mechanisms by which eosinophils are proposed to exert their protective effects is the production of DNA-based extracellular traps (ETs). Remarkably, DNA serves a role that extends beyond its biochemical function in encoding RNA and protein sequences; it is also a highly effective substance for entrapment of bacteria and other extracellular pathogens, and serves as valuable scaffolding for antimicrobial mediators such as granule proteins from immune cells. Extracellular trap formation from eosinophils appears to fulfill an important immune response against extracellular pathogens, although overproduction of traps is evident in pathologies. Here, we discuss the discovery and characterization of eosinophil extracellular traps (EETs) in response to a variety of stimuli, and suggest a role for these structures in the pathogenesis of disease as well as the establishment of autoimmunity in chronic, unresolved inflammation.

Current understanding of allergic fungal rhinosinusitis

Studying the pathophysiology of allergic fungal rhinosinusitis (AFRS) has proved challenging. While this clinical entity is easily distinguishable based on the clinical criteria set forth by Bent and Kuhn twenty-five years ago, studies examining type 2 inflammatory profiles in AFRS can make it seem more alike other CRS subtypes than it is different. Still, evolving research seems to clearly delineate this subtype from others in CRS. This review will critically evaluate the evolution of research examining the pathophysiology of AFRS and will conclude with a summary of the special considerations in the management of this fascinating disease.

Chronic rhinosinusitis: pathogenesis, therapy options, and more

INTRODUCTION

When rhinosinusitis - the inflammation of the nasal cavity and paranasal sinuses - persists for over 12 weeks, it is termed 'chronic rhinosinusitis' (CRS). Both innate and adaptive immunity contribute to the heterogeneous inflammatory pathogenesis of CRS, which is driven by genetic and environmental factors and the microbiome. CRS is classified by the presence of polyps. Molecular mechanisms in CRS with nasal polyps are similar to those in atopic diseases.

AREAS COVERED

This review focuses on the immune pathogenesis of CRS, differences between the two CRS subtypes, and latest treatments that may aid in the provision of personalized medicine.

EXPERT OPINION

Basic research in the last decade has helped significantly in enhancing our knowledge of the pathophysiologic processes of CRS, due to which there is now a better understanding of the associated natural history, physiopathology, novel treatments, and prevention strategies. Treatment success depends on the clarification of the underlying pathogenesis and disease-contributing factors. The exploration of disease endotypes and introduction of novel agents are important advancements. Prior studies performed without disease-endotyping resulted in the inefficiency of certain drugs and insignificant results. The identification of biomarkers, development of personalized approaches, and utilization of disease algorithms are required for CRS therapy success.

An Evaluation of SPARC Protein as a Serum Biomarker of Chronic Rhinosinusitis

OBJECTIVE

Precision medicine initiatives for chronic rhinosinusitis (CRS) management suggest tailoring treatment to the patient's individual disease profile; however, serum biomarkers for evaluation of disease activity or predicting response to therapy are lacking in CRS. Epithelial-to-mesenchymal transition (EMT) has been described as a component of barrier dysfunction in CRS. SPARC (secreted protein acidic and rich in cysteine) is a marker of EMT that has previously been identified in sinus epithelium by gene expression profiling. We wished to determine if SPARC could represent a serum biomarker for CRS by verifying (1) if SPARC could be detected in serum, (2) whether levels were sensitive to disease burden reduction following surgery, and (3) if it could predict response to therapy.

STUDY DESIGN

Prospective.

SETTING

Tertiary care center.

SUBJECTS

Patients with CRS undergoing endoscopic sinus surgery (ESS).

METHODS

Twenty-six patients undergoing ESS for CRS were prospectively recruited. Serum was collected at the time of surgery and 4 months following ESS and SPARC level measured using enzyme-linked immunosorbent assay. Postoperative outcome was characterized as "remission" or "unfavorable" based on symptomatology and endoscopy.

RESULTS

SPARC could be detected and measured in serum in all subjects. Following ESS, SPARC levels decreased by 33% ( P = .005) but did not predict evolution at 4 months postsurgery ( P = .94).

CONCLUSION

SPARC may be an interesting serum biomarker of disease activity in CRS, as it can be reliably measured and decreases following successful reduction of disease burden after surgery. However, it does not predict post-ESS evolution, suggesting that the link between EMT and outcome is not linear.

C3a receptor antagonism as a novel therapeutic target for chronic rhinosinusitis

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an inflammatory disease with an unknown etiology. Recent studies have implicated the complement system as a potential modulator of disease immunopathology. We performed proteomic pathway enrichment analysis of differentially increased proteins, and found an enrichment of complement cascade pathways in the nasal mucus of individuals with CRSwNP as compared to control subjects. Sinonasal mucus levels of complement 3 (C3) correlated with worse subjective disease severity, whereas no significant difference in systemic C3 levels could be determined in plasma samples. Given that human sinonasal epithelial cells were the predominate sinonasal source of C3 and complement anaphylatoxin 3a (C3a) staining, we focused on their role in in vitro studies. Baseline intracellular C3 levels were higher in CRSwNP cells, and following exposure to Aspergillus fumigatus (Af) extract, they released significantly more C3 and C3a. Inhibition of complement 3a receptor (C3aR) signaling led to a decrease in Af-induced C3 and C3a release, both in vitro and in vivo. Finally, we found in vivo that C3aR deficiency or inhibition significantly reduced inflammation and CRS development in a mouse model of Af-induced CRS. These findings demonstrate that local sinonasal complement activation correlates with subjective disease severity, and that local C3aR antagonism significantly ameliorates Af-induced CRS in a rodent model.