IL-13-associated epithelial remodeling correlates with clinical severity in nasal polyposis

Supramolecular gel with enhanced immunomodulatory effects presents a minimally invasive treatment strategy for eosinophilic chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is an inflammatory disease characterized by persistent immune dysregulation, which presents considerable limitations in current medical therapy.

OBJECTS

This study investigates a supramolecular gel (PSPD), which aims to minimize systemic adverse effects through local injection, provide long-lasting anti-inflammatory effects, and modulate the mucosal immune microenvironment.

METHODS

The properties of PSPD were evaluated using rheological experiments. Biocompatibility assessments were conducted through CCK-8 and serum biochemical analyses. The balance between TH17 and Treg was determined using immunofluorescence (IF) and flow cytometry (FC). Additionally, sinus computed tomography (CT), and endoscopy were employed to evaluate mucosal swelling.

RESULTS

Rheological assessments revealed that PSPD possesses excellent self-healing and slow-release properties. CCK-8 and serum biochemical assays indicated that PSPD demonstrated superior biocompatibility. In nasal polyps, PSPD significantly inhibited IL17 expression. In an Eosinophilic Chronic Rhinosinusitis (ECRS) rat model, treatment with PSPD led to significant alleviation of nasal mucosal congestion. Furthermore, PSPD modulated the proliferation of TH17 and Treg as well as the expression of cytokines, ultimately reversing the TH17/Treg immune imbalance.

CONCLUSION

This multifunctional gel effectively sustains the modulation of TH17/Treg homeostasis, improving long-term disease management and representing a promising new therapeutic strategy for CRS, particularly in cases of ECRS.

Endotyping in Chronic Rhinosinusitis-An EAACI Task Force Report

Chronic rhinosinusitis (CRS) is a clinical syndrome defined by typical sinonasal symptoms persisting for at least 12 weeks. CRS is divided into two distinct phenotypes, CRS with nasal polyps (CRSwNP) and without (CRSsNP). The aim of the review is to provide an update on the current knowledge in CRS endotypes. The prevailing hypothesis regarding the pathogenesis of CRS suggests that dysfunctional interactions between the host and environmental stressors at the mucosal surface drive the diverse inflammatory mechanisms. Genetic and epigenetic variations in the mucosal immune system are believed to play a significant role in the pathomechanisms of CRS. Various environmental agents (such as microbes and irritants) have been implicated in CRS. In a healthy state, the sinonasal mucosa acts as a barrier, modulating environmental stimulation and mounting appropriate immune responses against pathogens with minimal tissue damage. Different endotypes may exist based on the specific mechanistic pathways driving the chronic tissue inflammation of CRS. There is a need to understand endotypes in order to better predict, diagnose, and treat CRS. This literature review provides an update on the role of the endotypes in CRS and the limitations of endotyping CRS in clinical practice. Understanding of the pathogenesis and optimal management of CRS has progressed significantly in the last decades; however, there still are several unmet needs in endotype research.

Omics in allergy and asthma

This review explores the transformative impact of omics technologies on allergy and asthma research in recent years, focusing on advancements in high-throughput technologies related to genomics and transcriptomics. In particular, the rapid spread of single-cell RNA sequencing has markedly advanced our understanding of the molecular pathology of allergic diseases. Furthermore, high-throughput genome sequencing has accelerated the discovery of monogenic disorders that were previously overlooked as ordinary intractable allergic diseases. We also introduce microbiomics, proteomics, lipidomics, and metabolomics, which are quickly growing areas of research interest, although many of their current findings remain inconclusive as solid evidence. By integrating these omics data, we will gain deeper insights into disease mechanisms, leading to the development of precision medicine approaches that promise to enhance treatment outcomes.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The mucosal concept in chronic rhinosinusitis: Focus on the epithelial barrier

Chronic rhinosinusitis (CRS) is a common chronic nasal cavity and sinus disease affecting a growing number of individuals worldwide. Recent advances have shifted our understanding of CRS pathophysiology from a physical obstruction model of ventilation and drainage to a mucosal concept that recognizes the complexities of mucosal immunologic variations and cellular aberrations. A growing number of studies have demonstrated the alteration of the epithelial barrier during inflammatory states. Therefore, the current review has focused on the crucial role of epithelial cells within this mucosal framework in CRS, detailing the perturbed epithelial homeostasis, impaired epithelial cell barrier, dysregulated epithelial cell repair processes, and enhanced interactions between epithelial cells and immune cells. Notably, the utilization of novel technologies, such as single-cell transcriptomics, has revealed the novel functions of epithelial barriers, such as inflammatory memory and neuroendocrine functions. Therefore, this review also emphasizes the importance of epithelial inflammatory memory and the necessity of further investigations into neuroendocrine epithelial cells and neurogenic inflammation in CRS. We conclude by contemplating the prospective benefits of epithelial cell-oriented biological treatments, which are currently under investigation in rigorous randomized, double-blind clinical trials in patients with CRS with nasal polyps.

[Difficult-to-treat chronic rhinosinusitis-when the standard treatment is not effective and biologics are not available]

BACKGROUND

In recent years, significant improvements have been made in the treatment options for uncontrolled chronic rhinosinusitis (CRS) refractory to standard medical and surgical therapy. This is the result of a better understanding of the pathophysiology and the resulting development of biologicals for CRS with nasal polyps (CRSwNP). However, biologics are not (yet) available for all patients in Europe.

OBJECTIVE

Based on the session "Difficult-to-treat CRS, when biologics are not available" at the 29th Congress of the European Rhinologic Society (ERS) 2023 in Sofia, Bulgaria, the treatment options for uncontrolled CRS with the exclusion of biologics will be discussed.

MATERIALS AND METHODS

The content of the presentations "Is there a place for antibiotics?" "Indications for revision surgery," "Novel systemic treatment options," "Novel local treatment options," and "Phototherapy for nasal polyps" are outlined and supported by a review of the literature.

RESULTS

Various treatment options are available for managing uncontrolled CRS, even if biologic treatments are unavailable. Treatment options for type‑2 (T2) CRS include steroid rinses, repeated short-term oral steroids, steroid-eluting stents, and extended sinus surgery. In the case of nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD), acetylsalicylic acid (ASA) desensitization can be considered. Non-T2 endotypes or CRS without nasal polyps (CRSsNP) may benefit from several weeks of macrolides and xylitol rinses.

CONCLUSION

To accurately assess the efficacy of second-line therapies for treatment of difficult-to-treat CRS within an endotype-specific framework, additional controlled clinical trials are needed that take into account the heterogeneity of CRS endotypes.

Endotypic heterogeneity and pathogenesis in chronic rhinosinusitis

PURPOSE OF REVIEW

This review aims to provide updates in realms of endotypic heterogeneity, pathogenesis at the molecular level, potential of biomarkers, and cutting-edge scope of biologics in CRS.

RECENT FINDINGS

High-dimensional analyses, such as transcriptomes, and machine learning, have significantly enhanced CRS endotyping, uncovering diverse pathogenetic mechanisms contributing to its heterogeneity. The dynamic process of epithelial remodeling in CRS pathogenesis has gained more clarity and support as exemplified by IL-13 and oncostatin M (OSM) that are shown intricately linked to epithelial barrier dysfunction. Moreover, anti-dsDNA autoantibody, BAFF, periostin, and cystatin SN show promise as potentials biomarkers, offering diagnostic and prognostic value for CRS.

SUMMARY

The identification of inflammatory molecules involved in endotype specific signaling pathways provides insights into the underlying mechanisms and verifiable biomarkers for diagnosis and prediction of disease severity. More comprehensive clinical studies should be conducted to facilitate biologics from bench to bedside in treating CRS.

Dupilumab-induced eosinophilia in patients with diffuse type 2 chronic rhinosinusitis

BACKGROUND

Dupilumab, a monoclonal anti-IL-4Rα antibody, is approved for several type 2 mediated inflammatory diseases like asthma, atopic dermatitis, and diffuse type 2 chronic rhinosinusitis (CRS). Clinical studies had reported a transient increase in blood eosinophils during dupilumab therapy. This study aimed to assess the impact of elevated blood eosinophils on clinical outcome and to investigate the cause of high blood eosinophil levels under dupilumab therapy.

METHODS

Patients suffering from diffuse type 2 CRS treated with dupilumab were examined on days 0, 28, 90, and 180 after therapy start. Sino-Nasal-Outcome-Test Score (SNOT-22), Total Nasal Polyp Score (TNPS), and blood samples were collected. Cytokine measurements and proteomics analysis were conducted. Flow cytometry analysis measured receptor expression on eosinophils.

RESULTS

Sixty-eighty patients were included. Baseline eosinophilia ≥0.3G/L was observed in 63.2% of patients, and in 30.9% of patients, eosinophils increased by ≥0.5G/L under dupilumab. Subjects with eosinophilia ≥0.3G/L at baseline had the best SNOT-22 mean change compared to no eosinophilia. Eosinophil elevation during dupilumab therapy had no impact on clinical scores. The eosinophil adhesion molecule VCAM-1 decreased significantly during therapy in all patients. The chemokine receptor CXCR4 was significantly down- and IL-4 upregulated in subjects with eosinophil increase.

CONCLUSION

Our findings suggest that increased eosinophils in type 2 CRS are associated with a good clinical response to dupilumab. Patients with elevated IL-4 at baseline developed dupilumab-induced transient eosinophilia. We identified the downregulation of VCAM-1 and surface markers CD49d and CXCR4 on eosinophils as possible explanations of dupilumab-induced eosinophilia.

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.

Type 2 diabetes mellitus increases postoperative recurrence risk in Chinese patients with chronic rhinosinusitis

BACKGROUND

The effect of type 2 diabetes mellitus (T2DM) on postoperative recurrence of chronic sinusitis (CRS) is unclear.

OBJECTIVE

To investigate the association between T2DM and postoperative recurrence in CRS patients.

METHODS

CRS patients who underwent surgery in our hospital from January 2018 to April 2020 were included and followed up for three years. Patients were classified into non-recurrent and recurrent CRS groups based on follow-up outcome, and logistic regression analysis was performed to identify risk factors for postoperative recurrence.

RESULTS

A total of 412 CRS patients were included of whom 68 had T2DM. The postoperative recurrence rate was significantly higher in the T2DM group compared to the non-T2DM group (p < .05). T2DM prevalence and fasting blood glucose (FBG) levels were higher in recurrent CRS patients than those in non-recurrent CRS cases (p < .05). Multivariate regression analyses showed that age, duration of disease, FBG, and comorbid allergic rhinitis (AR) were significantly associated with an increased risk of postoperative recurrence of CRS (p < .05). Furthermore, adjusted logistic regression model revealed that T2DM was an independent risk factor for postoperative recurrence of CRS (p < .05).

CONCLUSIONS

Elevated FBG levels may significantly influenced the postoperative recurrence of CRS in Chinese patients, and T2DM was an independent risk factor for recurrence.