Histopathology of ethmoid mucosa versus polyp tissue in diagnosing eosinophilic mucin rhinosinusitis

Tissue Eosinophils Threshold and its Association With Adult-Onset Asthma in Chronic Rhinosinusitis

INTRODUCTION

Tissue eosinophil counts (TEC) might serve as a biomarker linking chronic rhinosinusitis (CRS) and the presence of adult-onset asthma. This study aimed to determine if TEC in sinus mucosa/polyps in CRS patients is an independent indicator of asthma and to identify its optimal cut-off point.

METHODS

This cross-sectional study was conducted on primary CRS patients scheduled for surgery. All patients were assessed by a pulmonologist for asthma diagnosis. Tissues were collected during surgery and evaluated for TEC. Logistic regression and receiver operating characteristic analysis were used to determine significant factors and the optimal cut-off points of TEC associated with asthma.

RESULTS

A total of 103 CRS patients were included. Ten patients (9.7%) had underlying asthma, while 13 (12.6%) were first diagnosed by the pulmonologist. TEC ≥40 cells per high-powered field (HPF) exhibited a significant correlation with asthma (area under the curve = 0.71, p < 0.001). The sensitivity of this cut-off point was 0.70 (95% confidence interval [CI] = 0.47-0.87), and specificity was 0.66 (95% CI = 0.55-0.76). Positive predictive value and negative predictive value were 0.37 and 0.88, respectively. The cut-off point significantly associated with the presence of asthma, with an adjusted odds ratio of 3.13 (95% CI = 1.05-9.35, p = 0.04), controlling for polyps, allergic rhinitis, and computerized tomography (CT) score.

CONCLUSION

TEC in CRS patients can help determine the presence of adult-onset asthma, with an optimal threshold of ≥40 cells/HPF. This threshold is significantly associated with asthma independent of polyps, allergy, and CT score.

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.

Sirt5 affects the metabolic remodeling of eosinophils by negatively regulating the level of succinylation modification of Pkm2 in eosinophilic chronic rhinosinusitis

Objectives

This study aims to investigate the role of Sirt5 in regulating eosinophil maturation and activation, specifically focusing on primary eosinophils in mice at the genetic level. Additionally, the study aims to elucidate the underlying mechanism of Sirt5 in eosinophilic inflammation metabolism and identify potential drug targets for the treatment of chronic sinusitis. The findings of this study will provide new insights and a solid theoretical basis for the development of novel therapeutic strategies for eosinophilic chronic rhinosinusitis (eCRS).

Methods

Our study investigated the role of Sirt5 gene expression in both non-eCRS and eCRS. We examined the correlation between Sirt5 gene expression and disease severity as well as eosinophil infiltration. Additionally, we utilized a mouse model of eCRS to assess the impact of Sirt5 gene deletion on the disease. To further understand the underlying mechanisms, we conducted experiments at the single-cell level using bone marrow-derived eosinophils. We validated our findings through in vitro culture of eosinophils and intervention experiments. Through these experiments, we aimed to elucidate how Sirt5 regulates target proteins and reshapes their related metabolic pathways.

Results

There is a positive correlation between the severity of eCRS and the expression level of Sirt5 in nasal mucosa. Inhibiting Sirt5 expression can effectively alleviate the abnormal activation of eosinophils and the resulting inflammatory response in eCRS-affected nasal mucosa. Sirt5 exerts its influence on eosinophil metabolism by negatively regulating the succinylation level of pkm2, a critical gene in the amino acid biosynthesis pathway.

Conclusions

The severity of eCRS is closely associated with the expression level of Sirt5. Sirt5 plays a negative regulatory role in the succinylation level of Pkm2 in eosinophils, thereby influencing metabolic remodeling and functional activation in eCRS. Investigating Sirt5 and its downstream metabolic pathways could offer valuable insights into the disease's pathogenesis and facilitate the development of targeted therapeutic strategies. This research holds significant implications for clinical practitioners involved in the diagnosis and treatment of patients with eCRS.

Gαi1/3 signaling mediates IL-5-induced eosinophil activation and type 2 inflammation in eosinophilic chronic rhinosinusitis

Background

Uncontrolled severe eosinophilic chronic rhinosinusitis (eCRS) is associated with elevated levels of Th2 cells and raised immunoglobulin concentrations in nasal polyp tissue. eCRS is characterized by high eosinophilic infiltration and type 2 inflammation. Gαi1/3 proteins participate in allergic inflammation by regulating immune cells. Whether Gαi1/3 proteins have a role in the development of eCRS remains unknown.

Objectives

To investigate the association between Gαi1/3 expression levels and CRS and the underlying mechanisms.

Methods

Western blotting and immunohistology were used to detect Gαi1/3 expression. Correlations between Gαi1/3 and immune cells and clinical parameters were analyzed. Signaling pathway activation in IL-5-induced Gαi1/3-knockout or knockdown mouse embryonic fibroblasts (MEFs) and eosinophils (EoL-1 cells) was detected by western blotting. EdU/DAPI was used to evaluate the proliferation of EoL-1 cells. A CRS model was established using Gαi1/3-knockout mice, and histological analysis and inflammatory cytokine measurements were performed.

Results

Compared with the non-eCRS subset, the eCRS subset showed significantly increased Gαi1/3 expression levels. High nasal tissue Gαi1/3 levels were linked to high tissue eosinophil infiltration, and high disease severity and allergic conditions in CRS patients. Gαi1/3 were required for IL-5-induced Akt-mTOR and Erk activation in MEFs. In EoL-1 cells, Gαi1/3 was associated with IL-5-activated IL-5Rα, promoting IL-5Rα endocytosis and transducing downstream signaling. IL-5-induced EoL-1 cell proliferation and degranulation were suppressed after Gαi1/3 silencing. In a CRS murine model, immune cell infiltration and type 2 inflammation were largely impaired in Gαi1/3-double-knockout mice.

Conclusion

Increased Gαi1/3 expression levels in nasal tissue are linked to eosinophil infiltration and increased disease severity in CRS patients. Gαi1/3 contributes to eosinophil activation and participates in regulating allergic inflammation in CRS patients.

Dupilumab for the treatment of chronic rhinosinusitis with nasal polyposis

Introduction: Chronic rhinosinusitis with nasal polyps (CRSwNP) affects 1-2.5% of the population and is associated with significant adverse effects on quality of life (QoL). CRSwNP is strongly correlated with (late onset) asthma with 30-70% of the CRSwNP patients having asthma. Health-care spending in rhinosinusitis is high, especially because of indirect costs.Areas covered: In the last years, the recognition of endotyping as an essential presumption to precision medicine has significantly changed the integrated care pathways in the treatment of chronic rhinosinusitis. Dupilumab is the first biological available for the treatment of CRswNP, since late 2019. Treatment with dupilumab results in a significant improvement of QoL (measured as SNOT-22), rhinosinusitis disease severity, symptoms of rhinosinusitis, and especially sense of smell, nasal polyp score, Lund-Mackay CT score, and asthma outcomes (ACQ5 and FEV1) compared to placebo.Expert opinion: At this moment, the high cost of the treatment requires careful patient selection and within the EUFOREA and EPOS2020 context, experts have tried to give guidance based on today's data. We now need trials evaluating which patients benefit most from treatment with biologicals and in which patients the treatment is cost-effective.

Expression and Clinical Significance of Mucin Gene in Chronic Rhinosinusitis

PURPOSE OF REVIEW

This review highlights the expression and regulation of mucin in CRS and discusses its clinical implications.

RECENT FINDINGS

Chronic rhinosinusitis (CRS) is common chronic nasal disease; one of its main manifestations and important features is mucus overproduction. Mucin is the major component of mucus and plays a critical role in the pathophysiological changes in CRS. The phenotype of CRS affects the expression of various mucins, especially in nasal polyps (NP). Corticosteroids(CS), human neutrophil elastase (HNE), and transforming growth factor-β1 (TGF-β1) are closely related to the tissue remodeling of CRS and regulate mucin expression, mainly MUC1, MUC4, MUC5AC, and MUC5B. "It is expected that CS, HNE and TGF - β could be used to regulate the expression of mucin in CRS." However, at present, the research on mucin is mainly focused on mucin 5AC and mucin 5B, which is bad for finding new therapeutic targets. Investigating the expression and location of mucin in nasal mucosa and understanding the role of various inflammatory factors in mucin expression are helpful to figure out regulatory mechanisms of airway mucin hypersecretion. It is of great significance for the treatment of CRS.