Increased neutrophilia in nasal polyps reduces the response to oral corticosteroid therapy

Accumulation of long-chain unsaturated fatty acids in the airway inflammatory microenvironment drives eosinophil etosis and corticosteroid resistance

BACKGROUND

Eosinophilic inflammation is a feature of chronic rhinosinusitis with nasal polyps (CRSwNP). Patients with eosinophilic CRSwNP (ENP) tend to be refractory and prone to recurrence. Although there is increasing evidence linking lipid metabolic irregularities to eosinophilia, the particular lipid responsible for promoting eosinophilic inflammation and the precise molecular mechanisms involved remain unclear.

METHODS

Lipidomic atlas and metabolic pathway enrichment were identified by liquid chromatography-tandem mass spectrometry and RNA sequencing, respectively. Eosinophil extracellular trap cell death (EETosis) was detected by immunofluorescence microscopy and transmission electron microscopy. Functional analyses were performed on purified eosinophils.

RESULTS

The unbiased lipidomic atlas identified a specific accumulation in long-chain fatty acids (LCFAs) in ENP. Consistently, RNA-seq analysis confirmed the enrichment in long-chain unsaturated fatty acid metabolism pathway in ENP. In this lipid-rich airway inflammatory environment, EETosis including ETotic eosinophils, EETs release and Charcot-Leyden crystals (CLCs) generation was enhanced in ENP, and associated with disease severity. Further, we found that both saturated and unsaturated LCFAs, such as arachidonic acid, are critical fuel sources to trigger eosinophil activation and filamentous DNA release, whereas only arachidonic acid could induce crystalline Galectin10 (CLCs). Mechanistically, arachidonic acid induces EETosis through a mechanism independent of reactive oxygen species but the IRE1α/XBP1s/PAD4 pathway. Both the long-acting dexamethasone and short-acting hydrocortisone, while facilitate eosinophil apoptosis, are ineffective to block arachidonic acid-induced EETosis.

CONCLUSIONS

Our findings demonstrate a previously unknown role of the LCFA arachidonic acid in mediating EETosis and glucocorticoid insensitivity to drive ENP progression, which may lead to novel insights regarding the treatment of patients with refractory eosinophilic inflammation.

Effects of inflammatory endotypes on disease trajectory in chronic rhinosinusitis with nasal polyps

BACKGROUND

Although phenotypic features have traditionally guided treatment in chronic rhinosinusitis, recent research has favored categorization on the basis of inflammatory endotype. However, the impact of endotypic differeces on clinical outcomes remains largely unknown.

OBJECTIVE

We sought to compare disease trajectory, primarily time-to-polyp recurrence, between chronic rhinosinusitis with nasal polyp (CRSwNP) endotypes.

METHODS

Samples were obtained from patients with CRSwNP undergoing surgery between 2015 and 2023, and cytokine levels were measured using a multiplex bead assay. Principal-component analysis followed by hierarchical cluster analysis was used to identify endotype clusters. Clinical outcomes were subsequently compared between clusters.

RESULTS

Six CRSwNP disease clusters were identified among the 269 included patients. Cluster 1 (46.5%) was characterized by relatively low inflammation. Cluster 4 (13.3%) and cluster 6 (7.1%) also exhibited low inflammation but with elevated levels of IL-12/IL-21 and CCL5, respectively. Cluster 2 (4.5%) represented a mixed type 1/3 inflammatory endotype (IFN-γHigh/IL-4High/IL-17AHigh), and cluster 3 (10.0%) was characterized by an innate, proinflammatory response (IL-1βHigh/IL-6High/IL-8High). Cluster 5 (18.9%) exhibited type 2-dominant inflammation (IL-5High/IL-9High/IL-13High). When comparing disease trajectory, cluster 2 (IFN-γHigh/IL-4High/IL-17AHigh) and cluster 4 (IL-12High/IL-21High) had the shortest time-to-polyp recurrence, whereas cluster 3 (IL-1βHigh/IL-6High/IL-8High) demonstrated the longest time-to-recurrence (P < .001). Time-to-oral steroid course (P = .13) and time-to-biologic therapy (P = .43) were similar across clusters.

CONCLUSIONS

The study highlights the heterogeneous nature of CRSwNP and differences in disease trajectory between endotypes, notably that patients with mixed type 1 and type 3 inflammation demonstrate more recalcitrant disease. These findings suggest that therapies beyond traditional type 2 inflammation treatments may be needed to effectively reduce CRSwNP disease recurrence.

Fluctuation of tissue eosinophils in chronic rhinosinusitis with nasal polyp

INTRODUCTION

Tissue eosinophil count (TEC) is recommended for defining Type 2 chronic rhinosinusitis with nasal polyps (CRSwNP). TEC is usually assessed by a one-time polyp biopsy. Because TEC may change over time, its reliability for diagnosing type 2 CRSwNP has not been previously assessed. This study aims to explore whether TEC fluctuates across different time points.

METHODS

Adult patients with CRSwNP were prospectively recruited at Rajavithi Hospital, Thailand. Participants who had used any form of steroids within 4 weeks were excluded. Polyps were taken for TEC evaluation upon recruitment and repeated at 3 and 6 months. Participants were assessed using the 22-items Sinonasal Outcome Test (SNOT-22), Lund-Kennedy endoscopic score (LKES), blood eosinophil count, and its percentage at each time point.

RESULTS

Thirty-seven participants were enrolled. The medians (Quartiles 1-3) of TEC were 17 (4-53.5), 19 (5-47.5), and 21 (4.5-51) cells/high-powered field at 0, 3, and 6 months, respectively. Friedman's two-way analysis of variance showed no statistical differences across the three time points for TEC (p = 0.53), blood eosinophil counts (p = 0.61), blood eosinophil percentages (p = 0.23), SNOT-22 (p = 0.21), or LKES (p = 0.23). TEC significantly correlated with blood eosinophil counts at 0 and 3 months and with blood eosinophil percentages at 0, 3, and 6 months (all p < 0.05).

CONCLUSION

The study showed that TEC did not significantly fluctuate over time, aligning with blood eosinophil levels, SNOT-22, and LKES. This stability within the 6-month period supports the reliability of TEC from a single biopsy for clinical use in managing CRSwNP.

IL-8 promotes pyroptosis through ERK pathway and mediates glucocorticoid resistance in chronic rhinosinusitis with nasal polyps

OBJECTIVE

This study seeks to elucidate the role and molecular mechanisms of IL-8 in nasal epithelial cell pyroptosis and its impact on glucocorticoid (GC) resistance.

METHODS

We assessed the expression of pyroptosis-related biomarkers and IL-8 in tissues and human nasal epithelial cells (hNECs) from both control and nasal polyp patients using western blot. Their localization was determined through immunohistochemistry and immunofluorescence. Cell death and cytotoxicity assay, electron microscopy, ELISA, and immunofluorescence were utilized to investigate IL-8-induced pyroptosis and GC resistance in hNECs, alongside the examination of the involved signaling pathways via western blot and immunofluorescence. In a murine model, hematoxylin-eosin staining and immunohistochemistry clarified relationship between pyroptosis and GC resistance.

RESULTS

IL-8 and pyroptotic biomarker expression were significantly higher in nasal polyp-derived tissues and hNECs compared to controls. IL-8 showed a positive correlation and co-localized with the pyroptotic biomarkers. IL-8 triggered pyroptosis in hNECs by activating the ERK signaling pathway, leading to increased IL-1β and IL-18 secretion. Moreover, IL-8-induced pyroptosis was found to contribute to GC resistance by affecting phosphorylation of GC receptor Ser211. Inhibition of pyroptotic proteins mitigated IL-8-induced GC resistance both in vitro and in vivo.

CONCLUSION

Elevated IL-8 facilitates pyroptosis via the ERK signaling pathway and plays a significant role in GC resistance in nasal polyps.

The role and mechanism of extracellular traps in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a common inflammatory disease of the nose that affects millions of individuals worldwide. Recent research has introduced the concept of an immunologic endotype based on the pathological characteristics of CRS and the types of inflammatory cell infiltration. This endotype concept is conducive to understanding CRS pathology and guiding further targeted therapy. Eosinophils and neutrophils infiltrate different proportions in different CRS endotypes and release extracellular traps (ETs) as a response to the extracellular immune response. The mechanisms of formation and biological roles of ETs are complex. ETs can trap extracellular microorganisms and limit the range of inflammation to some extent; however, excessive and long-term ETs may be related to disease severity. This review summarises and explores the mechanism of ETs and the advances in CRS research and proposes new insights into the interaction between ETs and programmed cell death (including autophagy, pyroptosis, and necroptosis) in CRS, providing new ideas for the targeted therapy of CRS.

Neutrophils in nasal polyps exhibit transcriptional adaptation and proinflammatory roles that depend on local polyp milieu

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an inflammatory upper airway disease, divided into eosinophilic CRSwNP (eCRSwNP) and noneosinophilic CRSwNP (neCRSwNP) according to eosinophilic levels. Neutrophils are major effector cells in CRSwNP, but their roles in different inflammatory environments remain largely unclear. We performed an integrated transcriptome analysis of polyp-infiltrating neutrophils from patients with CRSwNP, using healthy donor blood as a control. Additional experiments, including flow cytometry and in vitro epithelial cell and fibroblast culture, were performed to evaluate the phenotypic feature and functional role of neutrophils in CRSwNP. Single-cell RNA-sequencing analysis demonstrated that neutrophils could be classified into 5 functional subsets, with GBP5+ neutrophils occurring mainly in neCRSwNP and a high proportion of CXCL8+ neutrophils in both subendotypes. GBP5+ neutrophils exhibited significant IFN-I pathway activity in neCRSwNP. CXCL8+ neutrophils displayed increased neutrophil activation scores and mainly secreted oncostatin M (OSM), which facilitates communication with other cells. In vitro experiments showed that OSM enhanced IL-13- or IL-17-mediated immune responses in nasal epithelial cells and fibroblasts. Our findings indicate that neutrophils display transcriptional plasticity and activation when exposed to polyp tissue, contributing to CRSwNP pathogenesis by releasing OSM, which interacts with epithelial cells and fibroblasts depending on the inflammatory environment.

Based on the clinical features of cytologically intrinsic chronic rhinosinusitis with nasal polyps

BACKGROUND

The clinical phenotypes of CRS, such as the presence or absence of polyps, cannot well reflect the pathophysiological mechanisms and characteristics of patients. Only by distinguishing the different internal types of CRS can we individualize patients more accurately.

OBJECTIVE

To investigate the clinical characteristics of chronic rhinosinusitis with different cell types (CRSwNP), and to provide a reference for the diagnosis and treatment of CRSwNP.

MATERIALS AND METHODS

The cytological endotypes of CRSwNP were divided into five groups by cluster analysis.

RESULTS

There was a significant difference in the proportion of CRSwNP with different endotypes. There were significant differences in peripheral blood eosinophils, cerebrovascular disease, and unilateral and bilateral nasal polyps among CRSWNP patients with different cytological types.

CONCLUSIONS

Mixed CRSwNP and eosinophilic CRSwNP are the most common, while neutrophilic CRSWNP is the least common. Eosinophilic CRSwNP is more common in bilateral nasal polyps, with a high recurrence rate and a high probability of olfactory dysfunction. Neutrophilic CRSwNP is more common in elderly patients with cardiovascular and cerebrovascular diseases. Compared with total serum IgE, the percentage of eosinophils in peripheral blood is more helpful for the diagnosis of eosinophilic CRSwNP.

Identification of hub genes associated with neutrophils in chronic rhinosinusitis with nasal polyps

Neutrophil infiltration plays a key role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). However, pertinent mechanisms remain poorly elucidated. Here, we obtained the data from gene expression omnibus (GEO) and gene set enrichment analysis (GSEA) to identify and validate neutrophil-associated hub genes in CRSwNP. We found that four neutrophil-associated hub genes, namely ICAM1, IL-1β, TYROBP, and BCL2A1, were markedly upregulated and positively correlated with neutrophil infiltration levels in patients with CRSwNP. Subsequently, this was confirmed by real-time quantitative PCR. In conclusion, we identified the role of neutrophil infiltration in the pathophysiology of CRSwNP, which may be the potential targets for the diagnosis and treatment of CRSwNP.

Enhanced IL-37-IL-1R8 axis is negatively associated with inflammatory and clinical severity of chronic rhinosinusitis with nasal polyps

Background

The importance of IL-37 and downstream signal in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) demanding further investigation.

Objective

We sought to address the potential importance of the IL-37-IL-1R8 axis in regulating inflammatory response in patients with CRSwNP.

Methods

Nasal polyp (NP) tissues and control sinonasal tissues were obtained from adult CRSwNP, chronic rhinosinusitis without nasal polyps patients and healthy control subjects. The mRNA and protein levels of IL-37 and IL-1R8 in nasal tissues were examined by using quantitative PCR, immunohistochemical staining, and immunoblotting. In addition, the regulation of IL-1R8 expression was evaluated in human nasal epithelial cells (HNECs) in the presence of different stimuli.

Results

The mRNA and protein levels of IL-37 and IL-1R8 were significantly elevated in nasal polyps compared with that in control tissues. IL-37 and IL-1R8 were mainly distributed in the epithelial layer and lamina propria of tissues. IL-1R8 mRNA level in nasal polys was negatively associated with eosinophil and neutrophil infiltration, as well as endoscopic score and computed tomography score. Moreover, the mRNA expression of IL-1R8 in HNECs was significantly increased by toll-like receptor agonists, but significantly inhibited by proinflammatory cytokines, which can be rescued by using steroid (DEX).

Conclusion

Our findings showed that enhanced IL-37-IL-1R8 axis in NP tissues was negatively associated with inflammatory and clinical severity of CRSwNP patients, which could be considered as a future therapeutic target in CRSwNP patients.

Correlation between inflammatory biomarkers and disease control in chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) may have a heterogeneous response to medical/surgical treatments based on endotypes. Data correlating biomarkers and severity of the disease are lacking. We aimed to determine if IL-5 and calprotectin may be useful in defining severity of disease and identifying uncontrolled patients.

METHODS

This was a case-control study including 81 patients with diffuse CRSwNP who underwent at least one previous surgery and treated with intranasal steroids. We enrolled 39 uncontrolled patients (SNOT-22 ≥ 40 and two or more cycles of systemic corticosteroids in last year) (Group A) and 42 controlled one (SNOT-22 < 40 and less than two cycles of systemic corticosteroids in last year) (Group B). We analyzed IL-5 and calprotectin in both nasal secretions and nasal polyp tissue.

RESULTS

Calprotectin and IL-5 were significantly higher in Group A in both secretions and tissue, and the higher the number of previous surgeries, the higher the levels detected in nasal secretions. At univariate analyses, smoking, asthma, non-steroidal anti-inflammatory drugs-exacerbated respiratory disease (NSAID-ERD), blood eosinophilia, neutrophils, and eosinophils at nasal cytology were significantly associated with uncontrolled disease. Multivariate analyses showed that asthma, NSAID-ERD, and IL-5 in nasal secretion/polyp tissue were significantly related to the risk of uncontrolled disease.

CONCLUSIONS

Our data suggest that asthma, NSAID-ERD, and IL-5 in nasal secretions/tissue may be helpful to identify more severe patients, as they are related to the risk of uncontrolled disease. Nonetheless, high levels of calprotectin and neutrophilia were also observed in uncontrolled patients, especially after multiple surgeries.

An End-to-End CRSwNP Prediction with Multichannel ResNet on Computed Tomography

Chronic rhinosinusitis (CRS) is a global disease characterized by poor treatment outcomes and high recurrence rates, significantly affecting patients' quality of life. Due to its complex pathophysiology and diverse clinical presentations, CRS is categorized into various subtypes to facilitate more precise diagnosis, treatment, and prognosis prediction. Among these, CRS with nasal polyps (CRSwNP) is further divided into eosinophilic CRSwNP (eCRSwNP) and noneosinophilic CRSwNP (non-eCRSwNP). However, there is a lack of precise predictive diagnostic and treatment methods, making research into accurate diagnostic techniques for CRSwNP endotypes crucial for achieving precision medicine in CRSwNP. This paper proposes a method using multiangle sinus computed tomography (CT) images combined with artificial intelligence (AI) to predict CRSwNP endotypes, distinguishing between patients with eCRSwNP and non-eCRSwNP. The considered dataset comprises 22,265 CT images from 192 CRSwNP patients, including 13,203 images from non-eCRSwNP patients and 9,062 images from eCRSwNP patients. Test results from the network model demonstrate that multiangle images provide more useful information for the network, achieving an accuracy of 98.43%, precision of 98.1%, recall of 98.1%, specificity of 98.7%, and an AUC value of 0.984. Compared to the limited learning capacity of single-channel neural networks, our proposed multichannel feature adaptive fusion model captures multiscale spatial features, enhancing the model's focus on crucial sinus information within the CT images to maximize detection accuracy. This deep learning-based diagnostic model for CRSwNP endotypes offers excellent classification performance, providing a noninvasive method for accurately predicting CRSwNP endotypes before treatment and paving the way for precision medicine in the new era of CRSwNP.

Allergic Rhinitis, Rhinosinusitis, and Asthma: Connections Across the Unified Airway

The upper and lower airways are referred to as a single, integrated entity in the unified airway paradigm. When an allergen exposure occurs, the body responds locally and systemically, causing inflammation in other respiratory sites. As a result, asthmatic lower airway inflammation frequently coexists with upper airway inflammation, such as allergic rhinitis. Otolaryngologists are in a unique position to detect undiagnosed lower airway illness, start the proper therapy, and improve patient outcomes since they regularly encounter patients with upper airway problems.

The cyclooxygenase-2 upregulation mediates production of PGE2 autacoid to positively regulate interleukin-6 secretion in chronic rhinosinusitis with nasal polyps and polyp-derived fibroblasts

Chronic rhinosinusitis (CRS) can be traditionally classified as CRSwNP [with nasal polyps (NPs)] and CRSsNP (without NPs) based on the clinical phenotypes but recently suggested to be classified by the endotypes. We have identified overexpression of the cyclooxygenase-2 (COX-2) gene in NP tissues of Taiwanese CRSwNP patients. Therefore, in this study, we sought to investigate its protein expression/location/distribution in NP specimens and explore its roles in nasal polyposis. The COX-2 protein and mRNA expression was found higher in NPs than that in the control and CRSsNP patients' nasal tissues, mainly located at the epithelium and subepithelial stroma. Consistently, the CRS-related peptidoglycan (PGN) and bradykinin provoked COX-2 mRNA and protein upregulation in the human NP-derived fibroblasts and caused PGE2, thromboxane A2 (TXA2), and interleukin (IL-6) secretion in culture medium. Further analysis revealed that the PI3K/Akt activation and COX-2 induction were necessarily required for PGN-induced IL-6 production/secretion and the induced PGE2, but not TXA2, was speculated to affect IL-6 protein trafficking and production. Finally, the IL-6 increase observed in vitro could also be detected in NP tissues. Collectively, we demonstrated here that COX-2 protein and IL-6 are overexpressed in human NP tissues. In response to PGN challenge, the PI3K/Akt activation and COX-2-mediated PGE2 autacoid correlates with extracellular IL-6 protein trafficking/production in NP-derived fibroblasts, which can additionally contribute to the production of Th17-related cytokines such as IL-17 and TNF-α. This study also suggests COX-2 as a special biomarker for CRSwNP endotyping and may highlight the importance of COX-2 inhibitors in treating CRSwNP.

A Novel Model of Staphylococcus aureus-Induced Lymphoplasmacytic Rhinosinusitis in Rats

Chronic rhinosinusitis (CRS) is characterized by sinonasal mucosal inflammation. Staphylococcus aureus (S. aureus) is associated with severe CRS phenotypes. Different animal models have been proposed to study the association of CRS and S. aureus. However, current animal models are expensive due to the use of large animals, have high barriers to ethics approval, or require invasive surgical intervention, necessitating a need for a model that can overcome these limitations. This study aimed at establishing a reliable and efficient rat lymphoplasmacytic inflammatory model for rhinosinusitis. Sprague Dawley rats received a daily intranasal application of 20 μL of saline, S. aureus CI-182 exoprotein (250 μg/mL), or exoprotein CI-182 in combination with S. aureus clinical isolate (CI-908 or CI-913) 108 colony-forming unit (CFU)/mL. The rats' sinuses were harvested at 1 and 2 weeks post-intervention. The CFU and histopathologic examination of inflammation were evaluated. S. aureus clinical isolates CI-908 or CI-913 in combination with the exoprotein (CI-182) had higher CFUs and caused persistently higher inflammation at both the 1 and 2-week post-intervention compared to the exoprotein and saline group. The observed inflammatory cell type was lymphoplasmacytic. This study provided evidence that the combination of a S. aureus exoprotein with S. aureus induces inflammation that persists for a minimum of two weeks post-intervention. This model is the first known animal model to create the lymphoplasmacytic inflammation subtype seen in CRS patients. This offers a cost-effective, accessible, non-invasive, and easy-to-replicate model to study the causes and treatment of such inflammation.

Neutrophil extracellular traps promote ΔNp63+ basal cell hyperplasia in chronic rhinosinusitis

BACKGROUND

Neutrophil extracellular traps (NETs) are observed in chronic rhinosinusitis (CRS), although their role remains unclear.

OBJECTIVES

This study aimed to investigate the influence of NETs on the CRS epithelium.

METHODS

Forty-five sinonasal biopsy specimens were immunofluorescence-stained to identify NETs and p63+ basal stem cells. Investigators treated human nasal epithelial cells with NETs and studied them with immunofluorescence staining, Western blotting, and quantitative real-time PCR. NET inhibitors were administered to a murine neutrophilic nasal polyp model.

RESULTS

NETs existed in tissues in patients with CRS with nasal polyps, especially in noneosinophilic nasal polyp tissues. p63+ basal cell expression had a positive correlation with the release of NETs. NETs induced the expansion of Ki-67+p63+ cells. We found that ΔNp63, an isoform of p63, was mainly expressed in the nasal epithelium and controlled by NETs. Treatment with deoxyribonuclease (DNase) I or Sivelestat (NET inhibitors) prevented the overexpression of ΔNp63+ epithelial stem cells and reduced polyp formation.

CONCLUSIONS

These results reveal that NETs are implicated in CRS pathogenesis via basal cell hyperplasia. This study suggests a novel possibility of treating CRS by targeting NETs.

Immune endotyping and gene expression profile of patients with chronic rhinosinusitis with nasal polyps in the aspirin-exacerbated respiratory disease (AERD) and the non-AERD subgroups

BACKGROUND

Chronic Rhinosinusitis (CRS) is a paranasal sinus inflammatory disease and is divided into two subgroups defined as CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). CRSwNP displays a T helper (Th)2 biased phenotype, and based on sensitivity or tolerance to aspirin or non-steroidal anti-inflammatory drugs (NSAID), is further subdivided into Aspirin-exacerbated respiratory disease (AERD) and non-AERD groups. Considering the challenge of diagnosis and treatment in patients with CRSwNP, particularly the AERD subtype, and the significance of endotyping in these patients, we examined the immune profile and endotyping based on gene expression analysis in the AERD and the non-AERD groups of patients with CRSwNP.

MATERIAL AND METHOD

In this study, 21 patients were enrolled and were categorized into AERD (N = 10) and non-AERD (N = 11) groups based on their sensitivity to aspirin. After the special washing period, nasal polyps were biopsied in both groups, and the infiltration of eosinophils, neutrophils, plasma cells, and lymphocytes was compared between the AERD and the non-AERD groups. Also, gene expression levels of transcription factors including Tbet, GATA3, RoRγt, and FoxP3 and inflammatory cytokines including interleukin (IL)1β, IL1RAP (IL1 receptor accessory protein), IL2, IL4, IL5, IL10, IL13, IL17, TNFα, and IFNγ were investigated by quantitative Real-time PCR (qRT-PCR). Statistical analyses were performed using analytical tests including Kolmogorov-Smirnov, Mann-Whitney, and T-test. A P value less than 0.05 was considered statistically significant.

RESULTS

The mean ± SD age of the studied groups was 37 ± 8.7 years old (21-50) for the AERD, and 40.4 ± 7.7 years old (31-52) for the non-AERD. LMS/EPOS/SNOT scores and pulmonary function tests showed no difference between the two groups. Serum immunoglobulin E (IgE) levels were found to be higher in patients with AERD (p = 0.04), however, the peripheral blood counts of eosinophils were comparable in the two groups. In the histopathologic analysis, the AERD group showed higher percentages of eosinophils (p = 0.04), neutrophils (p = 0.04), and plasma cells (p = 0.04) than the non-AERD group. Additionally, the gene expression levels of GATA3 (p = 0.001), IL4 (p = 0.04), IL5 (p = 0.007), and IL17 (p = 0.03) were significantly higher in the AERD than the non-AERD groups.

CONCLUSION

Higher gene expression levels of GATA3, IL4, IL5, and IL17 were observed in the AERD group compared with the non-AERD group. These findings point to distinct patterns of inflammation in patients with AERD, with a predominance of Th2 inflammation.

Interaction of eosinophilic and neutrophilic inflammation in patients with chronic rhinosinusitis

PURPOSE OF REVIEW

In the past year, the endotype of chronic rhinosinusitis (CRS) has been studied from a new perspective. Eosinophilic and neutrophilic inflammation are not independent processes in the pathogenesis of CRS. In this review, we will focus on recent research on mixed eosinophilic-neutrophilic inflammation in CRS and discuss the mechanism and potential treatments.

RECENT FINDINGS

Traditionally, patients with eosinophilic CRS (ECRS) present with severe clinical manifestations, comorbidities, and a higher recurrence rate. Recent studies have found that approximately 40% of patients with ECRS present with neutrophilic infiltration, while patients with predominantly eosinophilic infiltration along with neutrophilic inflammation present with more complex inflammation, clinical manifestations and exhibit refractory characteristics.

SUMMARY

The complex inflammatory profile and refractory clinical characteristics of mixed eosinophilic-neutrophilic inflammation in CRS are current challenges for clinicians. We summarize the features of eosinophilic and neutrophilic inflammation and current studies on the mechanisms of mixed eosinophilic-neutrophilic inflammation and suggest potentially effective therapeutic methods. We hope that this review will help with determining precise treatment options for patients.

The current findings in eosinophilic chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a persistent inflammatory disease of the nasal cavity and paranasal sinuses. Traditional classification is denoted by the presence (CRSwNP) or absence of nasal polyps (CRSsNP). Particularly, CRSwNP is distinguished by the presence of infiltrating cells and inflammatory markers in the nasal mucosa. Patients with CRSwNP in Western countries predominantly display a type 2 endotype, whereas those in Asian regions display a mixed type 2 endotype. Nevertheless, recent transcriptome analyses have revealed two types of nasal polyps - type 2 and non-type 2 polyps, suggesting that geographical differences in endotypes likely resulted from the different proportions of each endotype. Moreover, various endotypes of CRSsNP have been identified, making phenotype a crucial factor for predicting treatment efficacy. Type 2 endotypes, designated as eosinophilic CRS (ECRS) in Japan, are characterized by severe eosinophilic infiltration into the paranasal sinus tissue and are particularly refractory. In this review, we discuss the latest developments in ECRS. We also provide recent findings on the involvement of nasal epithelial cells in pathogenesis.

Type 2 Biomarkers for the Indication and Response to Biologics in CRSwNP

PURPOSE OF REVIEW

Three biologics targeting type 2 inflammation have been approved for the treatment of severe and uncontrolled chronic rhinosinusitis with nasal polyps (CRSwNP). Nevertheless, around 40-60% of patients do not respond well to these biological treatments. Selecting appropriate patients is crucial to improve treatment outcome of biologics. This review summarizes the literature data on type 2 biomarkers, with a specific focus on the indication to biologics for severe CRSwNP.

RECENT FINDINGS

No consensus has been reached on how to define mucosal type 2 inflammation in CRSwNP. Clinical markers (e.g., 22-item Sino-nasal Outcome Test (SNOT-22) score, Lund-Mackay CT score (LMS), ethmoid/maxillary sinus CT score, and CT-radiomics), nasal secretion biomarkers (e.g., eosinophil cationic protein and interleukin-5), blood and nasal cytology eosinophil counts, and nasal swab eosinophil peroxidase activity have been reported to be associated with type 2 inflammation in CRSwNP. The time duration since the last surgery, SNOT-22 score at 1 week of treatment, and baseline serum osteoprotegerin levels might indicate the response to dupilumab. LMS and asthma control test scores were found to have moderate predictive value for acceptable improvement after 24-week treatment of omalizumab. High blood eosinophil levels at baseline were associated with treatment response to mepolizumab and benralizumab. Although several clinical and biological markers might be associated with type 2 inflammation and response to biologics in patients with CRSwNP, their validity requires further investigation. Identifying clinically applicable biomarkers for biologic treatment holds significant promise for advancing personalized approaches to biologics and optimizing treatment outcomes for patients with CRSwNP.

Enhanced oxidative stress is associated with tissue neutrophilia and poor steroid response in chronic rhinosinusitis with nasal polyps

Objective

To analyze the oxidative stress status and its association with tissue neutrophilia and oral steroid response in chronic rhinosinusitis with nasal polyps (CRSwNP) patients.

Methods

The levels of total oxidant status (TOS) were detected in the sinonasal tissues by using specific assay kits. Tissue neutrophil was examined by immunohistochemical staining, and oxidant status index (OSI) was evaluated in polyps tissues, and the messenger RNA (mRNA) levels of superoxide dismutase 2 (SOD2), aldehyde dehydrogenase 1 (ALDH1A1), and microsomal glutathione S-transferase 1 (MGST1) were examined using quantitative real-time polymerase chain reaction in the sinonasal tissues. The receiver operating characteristics (ROCs) curve of ALDH1A1, MGST1, and SOD2 mRNA levels were evaluated to determine the steroid response of CRSwNP patients.

Results

The levels of TOS and OSI were significantly higher in CRSwNP and CRSsNP than in normal controls, and OSI in polyps tissues was positively associated with tissue neutrophilia and poor steroid response. The ALDH1A1, MGST1, and SOD2 mRNA levels showed comparable accuracy as predictors of poor steroid response indicated by the area under the curve.

Conclusion

These findings provided evidence that the increased level of oxidative stress contributes to enhanced tissue neutrophilia and poor steroid response in CRSwNP patients.

The efficacy of steroid-eluting stents on the local inflammation of chronic rhinosinusitis with nasal polyposis after endoscopic sinus surgery: a multicenter prospective longitudinal study

PURPOSE

Attenuating local inflammation of chronic rhinosinusitis with nasal polyps (CRSwNP) after endoscopic sinus surgery (ESS) was crucial. Corticosteroids were generally exploited to ameliorate the postoperative state of CRSwNP. This study aims to verify the efficacy of steroid-eluting stents on the local inflammation of CRSwNP following ESS.

METHODS

57 CRSwNP were enrolled from September 2021 to April 2022. 30 were with stents, and 27 were without stents after ESS. Eosinophilic cationic protein (ECP), myeloperoxidase (MPO), eosinophil, and neutrophil levels in nasal secretions, as well as visual analog scale (VAS) and modified perioperative sinus endoscopy (POSE) scores, were assessed preoperatively and after 2, 4, 8, and 12 weeks.

RESULTS

All subjects of CRSwNP exhibited reduced results of eosinophil levels, neutrophil levels, nasal obstruction, nasal discharge, loss of smell, and total VAS scores after 12 weeks compared to the preoperative ones (p < 0.05). Compared with control subjects, CRSwNP with stents acquired lower levels of ECP, MPO, loss of smell, total VAS, and POSE scores at four follow-up visits, as well as reduced eosinophil and neutrophil levels in nasal secretions after 12 weeks (p < 0.05). Correlation analysis revealed that postoperative ECP and MPO levels of CRSwNP in nasal secretions correlated strongly with eosinophil and neutrophil levels, respectively, as well as POSE scores (r > 0.6).

CONCLUSION

These findings indicated that steroid-eluting stents might be an acclaimed option for CRSwNP in alleviating local inflammation to acquire a superior state after ESS.

Diverse Endotypes of Chronic Rhinosinusitis and Clinical Implications

Chronic rhinosinusitis (CRS) is a highly heterogeneous disease characterized by inflammation in the nasal and sinus mucosa. The CRS phenotypes, based on the presence or absence of nasal polyps, are known as CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). However, this classification has limitations in fully capturing the mechanisms and clinical manifestations of CRS. To address the heterogeneity of CRS, there has been a growing focus on classifying the condition into distinct endotypes. Endotype classification involves grouping patients based on specific molecular, immunological, and clinical characteristics, allowing for more personalized and targeted treatment approaches.This review delves into the current state of endotype classifications for CRS. It explores the role of geographic factors, microbiome, and subphenotype in shaping different endotypes. Additionally, the review examines how various clinical features are associated with specific endotypes, providing valuable insights into tailoring treatment options for better outcomes and transitions between different endotypes.Overall, this review offers a comprehensive and up-to-date perspective on the intricate realm of CRS endotype classifications. By unraveling the molecular and clinical intricacies, this review lays the foundation for more precise, effective, and individualized treatment strategies in the management of CRS.

Type 17 mucosal-associated invariant T cells contribute to neutrophilic inflammation in patients with nasal polyps

BACKGROUND

Immune regulation in chronic rhinosinusitis with nasal polyps (CRSwNP) with a neutrophilic endotype remains unclear. Mucosal-associated invariant T (MAIT) cells are tissue-resident innate T lymphocytes that respond quickly to pathogens and promote chronic mucosal inflammation.

OBJECTIVE

We aimed to investigate the roles of MAIT cells in neutrophilic CRSwNP.

METHODS

Nasal tissues were obtained from 113 patients with CRSwNP and 29 control subjects. Peripheral and tissue MAIT cells and their subsets were analyzed by flow cytometry. Polyp-derived MAIT cells were analyzed by RNA sequencing to study their effects on neutrophils.

RESULTS

Endotypes of CRSwNP were classified as paucigranulocytic (n = 21), eosinophilic (n = 29), neutrophilic (n = 39), and mixed granulocytic (n = 24). Frequencies of MAIT cells were significantly higher in neutrophilic (3.62%) and mixed granulocytic (3.60%) polyps than in control mucosa (1.78%). MAIT cell percentages positively correlated with local neutrophil counts. MAIT cells were more enriched in tissues than in matched PBMCs. The frequencies of MAIT1 subset or IFN-γ+ MAIT cells were comparable among control tissues and CRSwNP subtypes. The proportions of MAIT17 subset or IL-17A+ MAIT cells were significantly increased in neutrophilic or mixed granulocytic polyps compared with controls. RNA sequencing revealed type 17 and pro-neutrophil profiles in neutrophilic polyp-derived MAIT cells. In patients with neutrophilic CRSwNP, the proportions of MAIT and MAIT17 cells were positively correlated with local proinflammatory cytokines and symptom severity. In vitro experiments demonstrated that neutrophilic polyp-derived MAIT cells promoted neutrophil migration, survival, and activation.

CONCLUSIONS

MAIT cells from neutrophilic CRSwNP demonstrate type 17 functional properties and promote neutrophil infiltration in nasal mucosa.

A Decade of Pathogenesis Advances in Non-Type 2 Inflammatory Endotypes in Chronic Rhinosinusitis: 2012-2022

Chronic rhinosinusitis (CRS) is a heterogeneous disease characterized by localized inflammation of the upper airways. CRS includes two main phenotypes, namely, CRS with nasal polyps and CRS without nasal polyps. The phenotype-based classification method cannot reflect the pathological mechanism. The endotype-based classification method has been paid more and more attention by researchers. It is mainly divided into type 2 and non-type 2 endotypes. The mechanism driving the pathogenesis of non-type 2 inflammation is currently unknown. In this review, the PubMed and Web of Science databases were searched to conduct a critical analysis of representative literature works on the pathogenesis of non-type 2 inflammation in CRS published in the past decade. This review summarizes the latest evidence that may lead to the pathogenesis of non-type 2 inflammation. It is the main method that analyzing the pathogenesis from the perspective of immunology. Genomics and proteomics technique provide new approaches to the study of the pathogenesis. Due to differences in race, environment, geography, and living habits, there are differences in the occurrence of non-type 2 inflammation, which increase the difficulty of understanding the pathogenesis of non-type 2 inflammation in CRS. Studies have confirmed that non-type 2 endotype is more common in Asian patients. The emergence of overlap and unclassified endotypes has promoted the study of heterogeneity in CRS. In addition, as the source of inflammatory cells and the initiation site of the inflammatory response, microvessels and microlymphatic vessels in the nasal mucosal subepithelial tissue participate in the inflammatory response and tissue remodeling. It is uncertain whether CRS patients affect the risk of infection with SARS-CoV-2. In addition, the pathophysiological mechanism of non-type 2 CRS combined with COVID-19 remains to be further studied, and it is worth considering how to select the befitting biologics for CRS patients with non-type 2 inflammation.

Systemic corticosteroids in treatment of chronic rhinosinusitis-A systematic review

Purpose

When first-line chronic rhinosinusitis (CRS) treatment fails, patients can either be treated with oral or injected systemic corticosteroids. Although the EPOS and international guidelines for CRS do not mention injected corticosteroids, it is commonly used by ear, nose, and throat specialists. While the risks of systemic corticosteroids, in general, are known, the pros and cons of injected and oral corticosteroids (OCS) in CRS treatment are unclear.

Methods

A systematic review of studies that report the effects and/or side effects of injected and oral corticosteroids in the treatment of CRS was made according to the PRISMA guidelines.

Results

Altogether, 48 studies were included, only five studies reported on injected corticosteroids, and five attended with side effects. Three studies found beneficial effects of OCS perioperatively on sinus surgery, while four articles found no effect. Nineteen articles reported that OCS resulted in an improvement in symptoms. Two articles presented a longer-lasting effect of injected corticosteroids than OCS. Three studies reported adverse side effects of systemic corticosteroids, while two studies showed no adverse side effects. One study showed less adrenal suppression after injected corticosteroids compared to OCS. The evidence is not strong but shows a positive effect of systemic corticosteroids that lasts longer with injections.

Conclusion

Although systemic corticosteroids are widely used to treat CRS, there is a lack of studies comparing the OCS and injected corticosteroids. The evidence is sparse, however, injected steroids show longer effects with fewer side effects. An RCT study is needed to compare OCS and injected corticosteroids.

Use of peripheral blood eosinophils to guide post-operative glucocorticoid therapy in patients with chronic rhinosinusitis with nasal polyps: a randomised, controlled trial

OBJECTIVE

This study aimed to explore the utility of the eosinophil percentage in peripheral blood for guiding post-operative glucocorticoid therapy in patients with chronic rhinosinusitis with nasal polyps.

METHODS

Forty-four patients with chronic rhinosinusitis with nasal polyps underwent functional endoscopic sinus surgery and were randomly divided into two groups. Patients in the standard treatment group used oral and nasal spray glucocorticoids. In the biomarker treatment group, patients with peripheral blood eosinophil percentage values less than 3.05 per cent did not receive glucocorticoid treatment, whereas patients with values 3.05 per cent or above were part of the standard treatment group. Visual Analogue Scale, Sino-Nasal Outcome Test-22 scores, endoscopic Lund-Kennedy scores, eosinophils, interleukin-5 and eosinophil cationic protein in peripheral blood, and nasal secretions were measured.

RESULTS

After functional endoscopic sinus surgery, the Visual Analogue Scale, Sino-Nasal Outcome Test-22 and Lund-Kennedy scores were significantly reduced in both groups; there were no significant differences in those indicators between the groups during the three follow-up visits.

CONCLUSION

Peripheral blood eosinophil percentage offers a potential biomarker to guide post-operative glucocorticoid therapy in patients with chronic rhinosinusitis with nasal polyps.

Diagnostic value of myeloperoxidase and eosinophil cationic protein in nasal secretions for endotypes of chronic rhinosinusitis

OBJECTIVES

To explore associations between inflammatory endotypes and clinical presentations in CRS. To investigate the value of secretions myeloperoxidase (MPO) and eosinophilic cationic protein (ECP) detections in the diagnosis of endotypes of chronic rhinosinusitis (CRS), so as to provide guidance for the clinical application of MPO and ECP detection in secretions.

METHODS

We collected clinical symptom scores from patients with CRS and examined the differences between endotypes in clinical features. Patients' nasal secretions and polyps (or middle turbinate for control) were collected and their NEU number, EOS%, MPO and ECP levels were measured. Correlation analysis was performed for these biomarkers in secretions and tissues, respectively. Receiver operating characteristic curves were used to assess the predictive potential of the biomarkers mentioned above in nasal secretions.

RESULTS

Patients with Eos+Neu+ and Eos+Neu-CRS scored highest in most clinical symptom scores, while Eos-Neu+ and Eos-Neu-CRS scored lowest. Correlation analysis showed that tissues NEU number was correlated with NEU number and MPO level in nasal secretions (R = 0.4088; 0.6613); tissues EOS % was correlated with EOS% and ECP level in nasal secretions (R = 0.2344; 0.5774). To diagnose Neu+CRS, the highest area under the curve (AUC) (0.8961) was determined for MPO in secretions; the highest AUC (0.7400) was determined for NEU number in secretions. To diagnose Eos+Neu-CRS from Eos-Neu-CRS in Neu-CRS, the highest AUC (0.8801) was determined for ECP in secretions.

CONCLUSIONS

Clinical presentations are directly associated with CRS endotypes. Measurement of MPO and ECP in nasal secretions is useful for the endotypes diagnosis of CRS.

A novel inflammatory endotype diagnostic model based on cytokines in chronic rhinosinusitis with nasal polyps

Background

Type 2 CRSwNP is characterized by severe symptoms, multiple comorbidities, longer recovery course and high recurrence rate. A simple and cost-effective diagnostic model for CRSwNP endotype integrating clinical characteristics and histopathological features is urgently needed.

Objective

To establish a clinical diagnostic model of inflammatory endotype in CRSwNP based on the clinical characteristics, pathological characteristics, and cytokines profile in the polyp tissue of patients.

Methods

A total of 244 participants with CRSwNP were enrolled at 2 different centers in China and Belgium from 2018 to 2020. IL-5 level of nasal polyp tissue was used as gold standard. Clinical characteristics were used to establish diagnostic models. The area under the receiver operating curve (AUC) was used to evaluate the diagnostic performance. The study was approved by the ethics board of the First Affiliated Hospital of Sun Yat-sen University ([2020] 302), and written informed consent was obtained from all subjects before inclusion.

Results

In total, 134 patients from China (training set) and 110 patients from Belgium (validation set) were included. The logistic regression (LR) model in predicting inflammatory endotype of CRSwNP showed the AUC of 83%, which was better than the diagnostic performance of machine learning models (AUC of 61.14%-82.42%), and single clinical variables. We developed a simplified scoring system based on LR model which shows similar diagnostic performance to the LR model (P = 0.6633).

Conclusion

The LR model in this diagnostic study provided greater accuracy in prediction of inflammatory endotype of CRSwNP than those obtained from the machine learning model and single clinical variable. This indicates great potential for the use of diagnostic model to facilitate inflammatory endotype evaluation when tissue cytokines are unable to be measured.

Precision medicine in chronic rhinosinusitis - using endotype and endotype-driven therapeutic options

INTRODUCTION

Chronic rhinosinusitis (CRS) is a heterogeneous disease, and its complex pathophysiological characteristics pose a challenge to its clinical treatment. CRS is distinguished not only by clinical phenotype but also by endotype characteristics, which are divided into type 2 CRS and non-type 2 CRS.

AREAS COVERED

In this review, we summarize and discuss current studies that depict the mechanisms and endotypes of CRS. In particular, inflammatory cells and the microbiome play a role in the pathophysiology of CRS. We also listed some of the biomarkers described in recent studies that may serve as a theoretical foundation for additional investigations. We have summarized the advantages and disadvantages of existing treatments and listed the available biological treatments for CRS in detail.

EXPERT OPINION

Endotype-driven therapeutic options face many challenges because of the complexity of the disease. Glucocorticoids, nasal endoscopic surgery, and biological therapy are the main treatments used in clinical practice, but they have limitations. This review provides advice on the clinical management and treatment options for patients with different endotypes, which will be more conducive to improving the quality of life and reducing the financial burden on patients.

A review of current biomarkers in chronic rhinosinusitis with or without nasal polyps

INTRODUCTION

Chronic rhinosinusitis (CRS) is a heterogeneous disease with a variety of cellular and molecular pathophysiologic mechanisms. Biomarkers have been explored in CRS using various phenotypes, such as polyp recurrence after surgery. Recently, the presence of regiotype in CRS with nasal polyps (CRSwNP) and the introduction of biologics for the treatment of CRSwNP has indicated the importance of endotypes, and there is a need to elucidate endotype-based biomarkers.

AREAS COVERED

Biomarkers for eosinophilic CRS, nasal polyps, disease severity, and polyp recurrence have been identified. Additionally, endotypes are being identified for CRSwNP and CRS without nasal polyps using cluster analysis, an unsupervised learning technique.

EXPERT OPINION

Endotypes in CRS have still being established, and biomarkers capable of identifying endotypes of CRS are not yet clear. When identifying endotype-based biomarkers, it is necessary to first identify endotypes clarified by cluster analysis for outcomes. With the application of machine learning, the idea of predicting outcomes using a combination of multiple integrated biomarkers, rather than a single biomarker, will become mainstream.

Improvement of Suspected Eosinophilic Otitis Media with Targeted Biologic Therapy

OBJECTIVE

To compare the responses of suspected eosinophilic otitis media to treatment with or without a targeted biologic therapy against interleukin-4 (IL-4), IL-5, or IL-13 signaling.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

Subjects with type 2 chronic rhinosinusitis with nasal polyposis (CRSwNP), asthma, and otitis media who underwent treatment between 2005 and 2021.

INTERVENTION

Treatment with targeted biologic therapy.

MAIN OUTCOME MEASURES

Pre- and posttreatment nasal endoscopy, ear examination, and audiologic evaluation.

RESULTS

Four hundred seventy-seven subjects with type 2 CRSwNP were treated between 2005 and 2021. Sixty-two had otitis media with pre- and posttreatment evaluation. Retrospective chart review assessed pre- and posttreatment exam findings, nasal endoscopy, audiometry, and tympanometry. Nineteen subjects received a biologic therapy, whereas 43 did not. Exam, endoscopy, and tympanometry were graded for severity and compared pre- and posttreatment. Subjective ear exam and tympanometry were significantly improved with biologic therapy (control = 0.05, biologic = 0.84, p = 9.3 × 10 -5 ; control = -0.1, biologic = 0.62, p = 0.0002). Conductive hearing loss as assessed by air-bone gaps did not change between groups (control = 1.2 dB better, biologic = 1.2 dB worse, p = 0.32). Nasal endoscopy findings improved with biologic therapy relative to the control group, although not statistically significant (control = 1.04, biologic = 1.36, p = 0.22).

CONCLUSIONS

Biologic therapies targeting interleukin-4 (IL-4), IL-5, and IL-13 signaling are potential new treatments for eosinophilic otitis media. This is the largest study demonstrating improvement in subjects with suspected eosinophilic otitis media in response to biologic therapy, and immune modulation represents a novel treatment strategy for this challenging condition.

PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED

Current treatment strategies for otologic symptoms in eosinophilic disease are not tremendously effective or durable, resulting in a need for improved treatment options.

LEARNING OBJECTIVE

To determine if targeted biologic therapy, often used for eosinophilic asthma and type 2 chronic rhinosinusitis with nasal polyposis, improves coexistent suspected eosinophilic otitis media.

DESIRED RESULT

Treatment of suspected eosinophilic otitis media with targeted biologic therapy will result in improvement of otologic symptoms with a durable response compared with current treatment options.

LEVEL OF EVIDENCE

Level IV.

INDICATE IRB OR IACUC

Exempt. HUM00182703.

Evidence that oncostatin M synergizes with IL-4 signaling to induce TSLP expression in chronic rhinosinusitis with nasal polyps

BACKGROUND

Oncostatin M (OSM) may promote type 2 inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP) by inducing thymic stromal lymphopoietin (TSLP).

OBJECTIVE

We sought to study the impact of OSM on TSLP synthesis and release from nasal epithelial cells (NECs).

METHODS

OSM receptors, IL-4 receptors (IL-4R), and TSLP were evaluated in mucosal tissue and primary NECs from patients with CRSwNP by quantitative PCR and immunofluorescence. Air-liquid interface-cultured NECs were stimulated with cytokines, including OSM, and quantitative PCR, ELISA, Western blot, and flow cytometry were used to assess the expression of OSM receptors, IL-4R, and TSLP.

RESULTS

Increased levels of OSM receptor β chain (OSMRβ), IL-4Rα, and TSLP were observed in nasal polyp tissues and primary epithelial cells from nasal polyps of patients with CRSwNP compared with control tissues or cells from control subjects. The level of expression of OSMRβ in tissue was correlated with levels of both IL-4Rα and TSLP. OSM stimulation of NECs increased the expression of OSMRβ and IL-4Rα. Stimulation with IL-4 plus OSM augmented the production of TSLP; the response was suppressed by a signal transducer and activator of transcription 6 inhibitor. Stimulation of NECs with IL-4 plus OSM increased the expression of proprotein convertase subtilisin/kexin 3, an enzyme that truncates and activates TSLP.

CONCLUSIONS

OSM increases the expression of IL-4Rα and synergizes with IL-4 to induce the synthesis and release of TSLP in NECs. Because the combination of IL-4 and OSM also augmented the expression of proprotein convertase subtilisin/kexin 3, these results suggest that OSM can induce both synthesis and posttranslational processing/activation of TSLP, promoting type 2 inflammation.

Perturbated glucose metabolism augments epithelial cell proinflammatory function in chronic rhinosinusitis

BACKGROUND

Glucose concentrations are increased in nasal secretions in chronic rhinosinusitis (CRS). However, the glucose metabolism and its contribution to disease pathogenesis in CRS remain unexplored.

OBJECTIVES

We sought to explore the glucose metabolism and its effect on the function of nasal epithelial cells in CRS with and without nasal polyps (CRSwNP and CRSsNP).

METHODS

Glucose metabolites were detected with mass spectrometry. The mRNA levels of glucose transporters (GLUTs), metabolic enzymes, and inflammatory mediators were detected by quantitative RT-PCR. The protein expression of GLUTs was studied by immunofluorescence staining, Western blotting, and flow cytometry. Glucose uptake was measured by using fluorescent glucose analog. Human nasal epithelial cells (HNECs) were cultured. Bioenergetic analysis was performed with Seahorse XF analyzer. Gene expression in HNECs was profiled by RNA sequencing.

RESULTS

Increased glucose concentrations in nasal secretions was confirmed in both CRSsNP and CRSwNP. GLUT4, GLUT10, and GLUT11 were abundantly expressed in HNECs, whose expression was upregulated by inflammatory cytokines and D-glucose and was increased in CRS. Glucose uptake, glycolysis and tricarboxylic acid cycle metabolites, metabolic enzymes, and extracellular acidification rate and oxygen consumption rates were increased in HNECs in CRSsNP and CRSwNP, with a predominant shift to glycolysis. HNECs treated with high-level apical D-glucose showed enhanced glucose uptake, predominant glycolysis, and upregulated production of IL-1α, IL-1β, TNF-α, CCL20, and CXCL8, which was suppressed by 2-deoxy-D-glucose, an inhibitor of glycolysis.

CONCLUSIONS

Increased glucose in nasal secretions promotes glucose uptake and predominant glycolysis in epithelial cells, augmenting the proinflammatory function of epithelial cells in CRS.

Sinonasal Stent Coated with Sustained-Release Varnish of Mometasone Furoate Inhibits Pro-Inflammatory Cytokine Release from Macrophages: An In Vitro Study

The aim of the study was to develop a sustained-release varnish (SRV) containing mometasone furoate (MMF) for sinonasal stents (SNS) to reduce mucosa inflammation in the sinonasal cavity. The SNS' segments coated with SRV-MMF or an SRV-placebo were incubated daily in a fresh DMEM at 37 °C for 20 days. The immunosuppressive activity of the collected DMEM supernatants was tested on the ability of mouse RAW 264.7 macrophages to secrete the cytokines' tumor necrosis factor α (TNFα) and interleukin (IL)-10 and IL-6 in response to lipopolysaccharide (LPS). The cytokine levels were determined by respective Enzyme-Linked Immunosorbent Assays (ELISAs). We found that the daily amount of MMF released from the coated SNS was sufficient to significantly inhibit LPS-induced IL-6 and IL-10 secretion from the macrophages up to days 14 and 17, respectively. SRV-MMF had, however, only a mild inhibitory effect on LPS-induced TNFα secretion as compared to the SRV-placebo-coated SNS. In conclusion, the coating of SNS with SRV-MMF provides a sustained delivery of MMF for at least 2 weeks, maintaining a level sufficient for inhibiting pro-inflammatory cytokine release. This technological platform is, therefore, expected to provide anti-inflammatory benefits during the postoperative healing period and may play a significant role in the future treatment of chronic rhinosinusitis.

Subjective symptoms as predictors for eosinophilic chronic rhinosinusitis with nasal polyps in the Chinese population

PURPOSE

To evaluate the putative association between subjective symptoms and eosinophilic inflammation in patients with chronic rhinosinusitis with nasal polyps (CRSwNP).

METHODS

A total of 102 patients with CRSwNP who underwent endoscopic sinus surgery were prospectively enrolled. The Sinonasal Outcomes Test-22 scores (SNOT-22), EuroQol 5-dimensional Questionnaire scores (ED-5D), and Lund-Mackay scores by computed tomography (CT) were obtained. Patients were grouped as eosinophilic CRSwNP (eCRSwNP) and non-eosinophilic CRSwNP (neCRSwNP). ECRSwNP was defined if tissue eosinophils of nasal polyps were greater than or equal to 8/HPF according to positive major basic protein (MBP) staining, and neCRSwNP otherwise.

RESULTS

Thirty neCRSwNP and 72 eCRSwNP patients were included. ECRSwNP patients had higher incidences of asthma (p = 0.001), allergic rhinitis (p = 0.001), and ethmoid-to-maxillary opacification ratio on CT scans (p < 0.001), whereas the proportion of purulent discharge (p < 0.001) and maxillary sinus score (p = 0.002) was higher in the neCRSwNP patients. There were no significant differences between patients on the mains of the EQ-5D health utility values and total SNOT-22 score. However, eCRSwNP patients had higher SNOT-22 scores of sneezing (p = 0.006), runny nose (p < 0.001), and ear/facial domain (p = 0.012), and lower scores of thick nasal discharge (p = 0.015) and blockage (p = 0.042). Sneezing, thick nasal discharge, and blockage/congestion of nose were recognized as independent factors of CRSwNP.

CONCLUSION

Sneezing was an independent predictor of eCRSwNP, and thick nasal discharge and blockage/congestion of nose were independent predictors of neCRSwNP.

Neutrophil Extracellular Traps in Airway Diseases: Pathological Roles and Therapeutic Implications

Neutrophils are important effector cells of the innate immune response that fight pathogens by phagocytosis and degranulation. Neutrophil extracellular traps (NETs) are released into the extracellular space to defend against invading pathogens. Although NETs play a defensive role against pathogens, excessive NETs can contribute to the pathogenesis of airway diseases. NETs are known to be directly cytotoxic to the lung epithelium and endothelium, highly involved in acute lung injury, and implicated in disease severity and exacerbation. This review describes the role of NET formation in airway diseases, including chronic rhinosinusitis, and suggests that targeting NETs could be a therapeutic strategy for airway diseases.

Treatment Strategy of Uncontrolled Chronic Rhinosinusitis with Nasal Polyps: A Review of Recent Evidence

Chronic rhinosinusitis (CRS) is recognized as a heterogeneous disease with a wide range of clinical features, resulting in significant morbidity and cost to the healthcare system. While the phenotypic classification is determined by the presence or absence of nasal polyps and comorbidities, the endotype classification has been established based on molecular biomarkers or specific mechanisms. Research on CRS has now developed based on information based on three major endotypes: types 1, 2, and 3. Recently, biological therapies targeting type 2 inflammation have been clinically expanded and may be applied to other inflammatory endotypes in the future. The purpose of this review is to discuss the treatment options according to the type of CRS and summarize recent studies on new therapeutic approaches for patients with uncontrolled CRS with nasal polyps.

Endotyping Chronic Rhinosinusitis with Nasal Polyps: Understanding Inflammation Beyond Phenotypes

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogenous group of inflammatory conditions impacting the nose and paranasal sinuses. Our understanding of the underlying pathobiology of CRSwNP has substantially improved due to ongoing translational research efforts. Advances in treatment options, including targeted respiratory biologic therapy for CRSwNP, allow for more personalized approaches for CRSwNP patient care. Patients with CRSwNP are typically classified to one or more endotype based on the presence of type 1, type 2, and type 3 inflammation. This review will discuss recent advances in our understanding of CRSwNP and how this may impact current and future treatment approaches for patients with CRSwNP.

Epidemiology and aetiology of chronic rhinosinusitis in Asia-A narrative review

BACKGROUND

Despite having a similar prevalence to Western populations, literature on chronic rhinosinusitis (CRS) in the Asian population is sparse. There is limited data on the epidemiology and aetiology of CRS in Asia.

OBJECTIVES

To review the current literature on the epidemiology and aetiology of CRS in Asia.

METHODS

This is a narrative review of published data on the epidemiology and aetiology of CRS. Studies on CRS in Asian countries, published in English and indexed on PubMed or Google Scholar were reviewed. Where available, data extracted included epidemiology, endotype and cytokine profiles and genetic profiles.

RESULTS AND CONCLUSION

The prevalence of CRS in Asia ranges widely from 2.1% to 28.4%. Type 2 inflammation has been reported in 5%-55% of Asian patients, with lower levels of Type 2 cytokines reported in head to head comparisons of Western versus Asian patients. Notably, there exists marked heterogeneity in criterion of the tissue eosinophilic infiltration for diagnosis of type 2 CRS. Our review suggests that differences in prevalence of CRS and proportion of eosinophilic CRS between Asia and Europe and the Americas requires further study. Large-scale Asian studies utilising standardised definitions are needed to bridge this gap. Head to head genetic and microbiomal analysis may also be useful in understanding differences in CRS between the Asian and Western populations.

Increased IL-1α expression in chronic rhinosinusitis with nasal polyps

PURPOSE

To examine whether and how interleukin (IL)-1α is involved in chronic rhinosinusitis with nasal polyps (CRSwNP).

METHODS

Nasal polyp (NP) and control tissues were collected from CRSwNP patients and control subjects. The expression of IL-1α and other proinflammatory cytokines (IL-1β, IL-8 and IL-13, etc.), as well as neutrophil and eosinophil accumulation, were examined in sinonasal tissues using immunohistochemical (IHC), immunofluorescent (IF) staining, qPCR, and Luminex, respectively. Moreover, the regulation of IL-1α expression and its effects on other proinflammatory cytokines were evaluated in cultured nasal epithelial cells (NECs).

RESULTS

The mRNA and protein levels of IL-1α were significantly higher in NP tissues compared to that in control tissues. IL-1α in polyp tissues was mainly located in epithelial cells and neutrophils. Polyps IL-1α level was significantly associated with IL-8, IL-1β, IL-6, IL-4 and IL-13 production, as well as tissue neutrophil infiltration. Moreover, poly (I:C), lipopolysaccharides, Flagellin, R848 and cytokines (IL-4, IL-5, and IL-13) significantly increased the expression of IL-1α in cultured NECs in vitro, and recombinant IL-1α significantly promoted production of IL-8 and CXCL1 in cultured NECs.

CONCLUSIONS

These findings provided the evidence that IL-1α were significantly increased in NP tissues, which may contribute to tissue neutrophilia in CRSwNP patients in China.

The Diagnostic and Prognostic Role of Biomarkers in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) refers to an inflammatory disease of the sinonasal mucosa, with a significant economic burden and impact on quality of life. The diagnosis of CRS is conventionally made on careful history and physical examination, including nasoendoscopic assessment which requires technical expertise. There has been increasing interest in using biomarkers in the non-invasive diagnosis and prognostication of CRS, tailored to the disease inflammatory endotype. Potential biomarkers currently being studied can be isolated from peripheral blood, exhaled nasal gases or nasal secretions, as well as sinonasal tissue. In particular, various biomarkers have revolutionized the way in which CRS is managed, revealing new inflammatory pathways where novel therapeutic drugs are employed to curb the inflammatory process, which may be different from one patient to the next. Biomarkers that have been extensively studied in CRS, such as eosinophil count, IgE, and IL-5, have been associated with a T_H2 inflammatory endotype which correlates with an eosinophilic CRSwNP phenotype that predicts a poorer prognosis, tends to recur after conventional surgical treatment, but responds to glucocorticoid treatment. Newer biomarkers that demonstrate potential, such as nasal nitric oxide, can support a diagnosis of CRS with or without nasal polyps, especially when invasive tests such as nasoendoscopy are unavailable. Other biomarkers such as periostin can be used to monitor disease course after treatment of CRS. With a personalized treatment plan, the management of CRS can be individualized, optimizing treatment efficiency and reducing adverse outcomes. As such, this review aims to compile and summarize the existing literature regarding the utility of biomarkers in CRS in terms of diagnosis and prognostication, and also makes recommendations for further studies to fill current knowledge gaps.

An Integrated Analysis Reveals Ciliary Abnormalities in Antrochoanal Polyps

Objective

The mechanisms underlying the antrochoanal polyps (ACPs) remained unclear. We aimed to identify the differentially expressed genes (DEGs) profile, the cilia-related genes expression levels and the morphological characteristics of ciliated cells in patients with ACPs.

Methods

We obtained ACPs biopsy samples from 28 patients and uncinate process from 27 healthy controls. Whole-transcriptome RNA sequencing, immunofluorescence staining, quantitative polymerase chain reaction, and scanning electron microscopy were performed.

Results

3739 DEGs were detected between ACPs and controls, and Gene Ontology analysis on these DEGs implicated cilium assembly, cilium motility, cilia component, cilia function, inflammatory response and immune system process were included in ACPs pathogenesis. Gene set enrichment analysis implicated sets of genes regulated in processes associated with cilium organization, cilium morphogenesis, cilium movement, axoneme assembly, axonemal dynein complex assembly and cell projection assembly. The expression levels of cilia-related genes (FOXJ1, DNAI1, DNAH9, RSPH1, RSPH9 and RSPH4A) were validated by quantitative polymerase chain reaction (Fold change >2, P<0.05) and FOXJ1 was positive correlated with DNAI1, DNAH9, RSPH4, RSPH1, RSPH9, DNAH5, DNALI1 in ACPs (all P < 0.05). Based on our semi-quantitative scoring system, median scores of α-Tubulin, DNAI1 and RSPH4A were significantly higher in ACPs than in controls. In addition, loss of ciliated cells and a shorter cilia pattern were further confirmed by immunofluorescence staining and scanning electron microscopy in ACPs.

Conclusion

The aberrant expression of cilia-related genes and ciliary structural impairment are an important pathological phenomenon in ACPs, and our findings may provide novel insights into understanding the mysterious mechanisms underlying ACPs.

Neutrophilic inflammation in chronic rhinosinusitis

PURPOSE OF REVIEW

Over the last years, extensive research has been done on neutrophils and their contribution in chronic rhinosinusitis (CRS), and made it clear that they are more than just a bystander in this disease. In this article, we will review all recent publications on this topic and look to what the future hold regarding therapeutics targeting the neutrophilic inflammation in CRS.

RECENT FINDINGS

Evidence is growing that the presence of neutrophils are associated with a worse disease outcome in certain CRS patient groups. They are highly activated in type 2 inflammations and exhibit damaging properties through their proteases, contributing to the chronicity of the disease. Several recent studies identified useful biomarkers and targets for future therapeutics.

SUMMARY

The findings we review in this manuscript are of utmost importance in unraveling the complexity of CRS and provide us with the necessary knowledge for future clinical practices.

Preliminary application of a 3D-printed track-guided precise drug delivery device for the sinuses after endoscopic sinus surgery

BACKGROUND

Conventional treatment for eosinophilic chronic rhinosinusitis with nasal polyps (eCRSwNP) is usually limited; consequently, relapses occur frequently, accurate local drug delivery is currently a research area of major interest.

METHODS

Based on postoperative nasal sinus computed tomography (CT) images, the 3D printing technique was used to design and fabricate a precise track-guided sinus drug delivery device. The control group was treated with glucocorticoids by nasal spray for 1 year according to the conventional method, while the experimental group received topical nasal glucocorticoids using the 3D-printed track-guided precise sinus drug delivery device for 1 year. Scores on the Sino-Nasal Outcome Test (SNOT-22) scale and the Lund-Kennedy nasal endoscopic scale during reexamination at 1 month, 3 months, 6 months, and 1 year after the operation were used as the basis for evaluation.

RESULTS

The follow-up duration was 12 months or more following endoscopic sinus surgery (ESS) with neosinus cavity formation. The two groups showed significant differences in SNOT-22 scores and nasal polyp Lund-Kennedy subscores at 3 months, 6 months, and 1 year (p < 0.001) and no differences in plasma cortisol at 6 months and 1 year (p > 0.05).

CONCLUSION

Local drug administration using our 3D-printed precise sinus drug delivery device is superior to conventional nasal cavity administration in controlling eCRS recurrence.

The Influence of Body Mass Index on Glucocorticoid Insensitivity in Chronic Rhinosinusitis with Nasal Polyps

BACKGROUND

Reasons for glucocorticoid (GC) insensitivity in chronic rhinosinusitis with nasal polyps (CRSwNP) are not completely clear. Here, we investigate the influence of body mass index (BMI) on GC insensitivity in eosinophilic CRSwNP (eosCRSwNP) and noneosinophilic CRSwNP (noneosCRSwNP) patients.

METHODS

We recruited 699 CRSwNP patients and gave them a course of oral methylprednisolone for 2 weeks (24 mg/day). Patient demographics and clinical features were analyzed in both GC-sensitive and GC-insensitive CRSwNP patients with different BMI levels and phenotypes.

RESULTS

35.3% of recruited CRSwNP patients were GC-insensitive, and the majority of GC-insensitive patients were males or prone to overweight & obese. Logistic regression analysis further confirmed that being overweight & obese was an independent risk factor for GC-insensitive of CRSwNP patients (odds ratio = 1.584, p = 0.049). Compared to underweight & normal-weight patients, overweight & obese patients were more likely to be GC insensitivity, particularly in the eosCRSwNP group, but not in the noneosCRSwNP group. However, there was no significant difference between the underweight & normal weight and the overweight & obese GC-insensitive eosCRSwNP patients regarding the number of infiltrated eosinophils, neutrophils, and polyp recurrence rate.

CONCLUSIONS

Collectively, our findings demonstrate for the first time that BMI contributes to GC insensitivity in eosCRSwNP patients.

A pathogenic integrated view explaining the different endotypes of asthma and allergic disorders

The inflammation of allergic diseases is characterized by a complex interaction between type 2 and type 3 immune responses, explaining clinical symptoms and histopathological patterns. Airborne stimuli activate the mucosal epithelium to release a number of molecules impacting the activity of resident immune and environmental cells. Signals from the mucosal barrier, regulatory cells, and the inflamed tissue are crucial conditions able to modify innate and adaptive effector cells providing the selective homing of eosinophils or neutrophils. The high plasticity of resident T- and innate lymphoid cells responding to external signals is the prerequisite to explain the multiplicity of endotypes of allergic diseases. This notion paved the way for the huge use of specific biologic drugs interfering with pathogenic mechanisms of inflammation. Based on the response of the epithelial barrier, the activity of resident regulatory cells, and functions of structural non-lymphoid environmental cells, this review proposes some immunopathogenic scenarios characterizing the principal endotypes which can be associated with a precise phenotype of asthma. Recent literature indicates that similar concepts can also be applied to the inflammation of other non-respiratory allergic disorders. The next challenges will consist in defining specific biomarker(s) of each endotype allowing for a quick diagnosis and the most effective personalized therapy.

Characterization of the Notch pathway in nasal polyps of patients with chronic rhinosinusitis: A pilot study

Chronic rhinosinusitis with nasal polyps is a widespread pathology characterized by persistent inflammation of nasal and paranasal mucosa. Although it represents one of the most frequent diseases of the nasal cavities, its etiology is still not completely elucidated. There is evidence suggesting that the Notch signaling, a highly conserved intercellular pathway known to regulate many cellular processes, including inflammation, is implicated in nasal polyps formation. The purpose of this study was to investigate the expression of genes of the Notch pathway in nasal polyps from patients with chronic rhinosinusitis. Nasal polyps and adjacent mucosa tissue were obtained from 10 patients. RNA was analyzed by quantitative reverse transcriptase-polymerase chain reaction for the expression level of (1) Notch pathway components such as receptors (NOTCH1-4), ligands (DLL4, JAGGED-1), and target genes (HEY1, 2, and HES1) and (2) genes providing information on the pathogenesis of polyposis (C-MYC and SCGB1A1) and on eosinophils content (CCL26, IL5, and SAA2). We report a Notch-driven gene expression pattern in nasal polyps which correlates with the expression of genes highly expressed in eosinophils, whose presence is an important parameter to define the pathophysiologic diversity characterizing nasal polyps. Taken together, our results suggest a role for Notch signaling in the pathophysiology of polyposis. Further studies are needed to elucidate the role of Notch in nasal polyps formation and to establish whether it could represent a novel therapeutic target for this pathology.

Role of NLRP3 Inflammasome on Different Phenotypes of Chronic Rhinosinusitis

BACKGROUND

The pathophysiologic mechanisms of human chronic rhinosinusitis (CRS) are highly complex, and sinonasal colonization with pathogens is the first and most important step in this process. NLRP3, the main receptor activated by pathogen-associated molecular patterns (PAMPs), is associated with a variety of inflammatory diseases, including airway inflammation; however, the understanding of its role in CRS is limited.

OBJECTIVE

By detecting the differential expression of the NLRP3 inflammasome and its downstream cytokines IL-1β and IL-18 between CRS patients and controls, between different CRS phenotypes (CRSsNP and CRSwNP), between mucosal tissue and polyp tissue, and further its relationship with neutrophilic/eosinic infiltration, we aimed to elucidate the biological role of the NLRP3 inflammasome in the pathophysiologic mechanisms of CRS.

METHODS

Fifteen cases in each control, CRSsNP, and CRSwNP groups (subdivided into mucosa tissue and polyp tissue) were included in this study. Differential expression of NLRP3/caspase-1 and its downstream cytokines IL-1β and IL-18 was investigated, and its relationship with neutrophilic and eosinophilic infiltration was analyzed. Fluorescent immunohistochemistry (F-IHC) was used to assess NLRP3 and caspase-1 expression, RT-PCR was used for mRNA level quantitation, and western blotting was employed to analyze the protein concentrations.

RESULTS

NLRP3 and cleaved caspase-1 were expressed at higher levels in both the CRSsNP and CRSwNP phenotypes than in the control nasal mucosa and at much higher levels in polyp tissue of CRSwNP (P < .05), which was in line with the expression of cleaved IL-1β and cleaved IL-18 (P < .05). Higher expression of NLRP3 had a mild correlation with neutrophilic infiltration but highly correlated with eosinophilic infiltration (R = 0.607, P < .01).

CONCLUSIONS

NLRP3 is involved in the pathogenesis of CRS, most likely by the NLRP3/caspase-1/IL-1β and IL-18 response. It induced eosinophilic infiltration in CRSwNP, especially in polyp tissue. As for whether NLRP3 induces neutrophilic infiltration, further experiments are needed to confirm.