Effects of PM2.5 on mucus secretion and tissue remodeling in a rabbit model of chronic rhinosinusitis

PM2.5 affected ciliary beat frequency of axonemes via the cyclic AMP-dependent protein kinase a pathway

Long-term inhalation of fine particulate matter (PM2.5) has been linked to the onset of various lung diseases. The mucociliary clearance system, acts as the primary host defense mechanism in the airways, with ciliary beat frequency (CBF) being a key parameter for assessing its functionality. The primary aim of this study was to demonstrate the impact of PM2.5 on CBF and to investigate the potential mechanisms by which PM2.5 induced changes in CBF through airway axonemes. Airway axonemes were extracted from bovine ciliated epithelium and treated with different concentrations of PM2.5 in vitro for 10 min and 1 h to simulate short-term and prolonged exposures. Additionally, the pathway was examined using PKA activator (cAMP) and PKA inhibitor (PKI) on ciliary axonemes. The results revealed that PM2.5 stimulated CBF in airway axonemes via the cAMP-PKA pathway. Low concentrations and short-term exposure to PM2.5 stimulated CBF elevation, however, high concentration and prolonged exposure to PM2.5 might damage respiratory cilia, thereby increasing the risk of respiratory diseases.

Long-Term Particulate Matter Exposure May Increase Risk of Chronic Rhinosinusitis WIth Nasal Polyposis: Results from an Exposure-Matched Study

BACKGROUND

Particulate matter ⩽2.5 µm in diameter (PM2.5) and its role in chronic rhinosinusitis (CRS) pathogenesis have gained heightened attention. We previously demonstrated that PM2.5 exposure may bias the nasal mucosa in CRS toward a Type 2 inflammatory pathway. However, there are limited data comparing cytokine changes in CRS sinonasal tissue to non-CRS patients as it relates to PM2.5 exposure. We hypothesized that long-term exposure preferentially increases the risk of manifesting CRS with nasal polyposis (CRSwNP).

METHODS

We performed a retrospective analysis of 376 patients (308 CRS, 68 controls) who underwent endoscopic sinus or skull base surgery. A spatiotemporal machine-learning model estimated daily PM2.5 levels for 1 year prior to each patient's surgery date. Cytokines were quantified using a multiplex flow cytometric bead assay and compared to estimated PM2.5 exposure using Spearman correlation and multivariate regression. Patients with high and low 12-month PM2.5 exposures were matched across age, sex, income, and rurality using a nearest neighbor algorithm. Multivariate adjusted logistic regression was used to estimate the odds of CRS based on PM2.5 exposure.

RESULTS

Reduced IL-10 levels were associated with higher PM2.5 exposures in control patients (β = -0.735, p = 0.0196). In exposure-matched logistic regression analysis, high 12-month PM2.5 exposure was an independent predictor of CRSwNP (β = 1.97, OR: 7.22, p = 0.0001) after adjustment for age, income, rurality, and comorbid asthma/allergic rhinitis. A similar relationship was not identified for CRSsNP.

CONCLUSIONS

PM2.5 exposure is associated with reduced IL-10 in control patients compared to CRS and may increase odds of CRSwNP development.

Mitigating intubation stress, mucosa injury, and inflammatory response in nasogastric tube intubation via suppression of the NF-κB signaling pathway by engineering a hydration lubrication coating

Nasogastric tube (NGT) intubation is a common yet critical clinical procedure. However, complications arising from tube friction result in awful pain and morbidity. Here, we report a straightforward surface modification of slender NGT utilizing highly hydrated micelles that were composed of hyaluronic acid and Pluronic. The strong intermolecular hydrogen bonding facilitated the assembly of the micelles on NGT via a one-step dip coating process. The micelle coating conferred excellent hydrophilic, lubrication, anti-protein adhesive, and biocompatible properties. The in vivo efficacy of the micelle coating in alleviating catheterization irritation and mucosal injury was demonstrated using an NGT intubation model of rabbits. More importantly, compared to the paraffin oil coating (the current clinical means), the micelle coating possessed superior capability to reduce the inflammatory reaction caused by NGT intubation. The underlying mechanism was attributed to the suppression of the TLR4-IKBα-NF-κB inflammatory signaling pathway. This work provides a promising solution for developing lubricant medical coatings.

Five-month real-ambient PM2.5 exposure impairs learning in Brown Norway rats: Insights from multi omics-based analysis

PM2.5, recognized as a potential pathogenic factor for nervous system diseases, remains an area with many unknowns, particularly regarding its effects on human health. After five-month real-ambient PM2.5 exposure, we observed no significant pathological damage to the lung, liver, spleen, or kidney tissues. However, PM2.5 exposure led to neuronal degeneration in the hippocampal CA1 region of Brown Norway (BN) rats. The level of IL-6, IL-13, IL-1β, IL-12, IL-4, GRO/KC, MIP-1α, CM-CSF significantly increased in lung lavage fluid (P < 0.05 for all). Notably, we detected a slight impairment in spatial learning ability, as evidenced by the Barnes maze training outcomes. There were no significant changes in the bacterial community in lung lavage fluid (P = 0.621), but the bacterial community in the gut significantly changed (P < 0.001), with more species identified (P < 0.05). The metabolomic analysis revealed 147 and 149 significantly changed metabolites in the pulmonary system and serum, respectively (P < 0.05). PM2.5 exposure caused a decrease in Nervonic acid (NA) in both the lung and serum, which likely contributed to spatial learning impairment (P < 0.01). The correlation between lung metabolites, gut bacterial species, and serum metabolites indicated that PM2.5 exposure likely impaired spatial learning through the lung-gut-brain axis pathway. Lung and serum metabolic disorders and intestinal microbial imbalance occurred in BN rats post-five-month real-ambient PM2.5 exposure. There were two potential ways that PM2.5 exposure caused the decline of spatial learning ability in wild-type BN rats: (1) PM2.5 exposure led to a significant decrease of neuroprotective Nervonic acid in lung and serum metabolites. (2) PM2.5 exposure likely led to reduced spatial learning ability through the lung-gut-brain axis.

The Role of the Environment and Occupational Exposures in Chronic Rhinosinusitis

PURPOSE OF REVIEW

The purpose of the review is to summarize the current literature and evaluate how different environmental exposures may contribute to the development and course of chronic rhinosinusitis (CRS). The review aims to explore the relationship between host factors and environmental exposures in the pathogenesis of CRS.

RECENT FINDINGS

Recent studies have helped establish the role of air pollutants, tobacco smoke, occupational exposures, and microplastics in the pathogenesis of CRS. These exposures have been shown to cause epithelial dysfunction and promote inflammation through different mechanisms and to different degrees. The pathogenesis of CRS is complex and multifactorial, with environmental exposures playing a key role in its onset and exacerbation. Research indicates that pollutants can damage the sinonasal epithelial barrier and disrupt the microbiome, leading to increased inflammation. A deeper understanding of the mechanisms behind this inflammatory process and its link to environmental exposures could enhance strategies for preventing and treating CRS.

Fine particulate matter manipulates immune response to exacerbate microbial pathogenesis in the respiratory tract

Particulate matter with a diameter ≤2.5 μm (PM2.5) poses a substantial global challenge, with a growing recognition of pathogens contributing to diseases associated with exposure to PM2.5 Recent studies have focused on PM2.5, which impairs the immune cells in response to microbial infections and potentially contributes to the development of severe diseases in the respiratory tract. Accordingly, changes in the respiratory immune function and microecology mediated by PM2.5 are important factors that enhance the risk of microbial pathogenesis. These factors have garnered significant interest. In this review, we summarise recent studies on the potential mechanisms involved in PM2.5-mediated immune system disruption and exacerbation of microbial pathogenesis in the respiratory tract. We also discuss crucial areas for future research to address the gaps in our understanding and develop effective strategies to combat the adverse health effects of PM2.5.

The Impact of Acute Peri-operative Particulate Matter Exposure on Endoscopic Sinus Surgery Outcomes: A Preliminary Multi-site Investigation

BACKGROUND

Environmental exposures have been postulated to play an important role in the pathophysiology of chronic rhinosinusitis (CRS). Particulate matter (PM) is one of the most widely studied ambient air pollutants, but its peri-operative impact on CRS is unknown.

OBJECTIVE

To determine the effect of acute, peri-operative PM exposure on outcomes after endoscopic sinus surgery (ESS).

METHODS

Participants with CRS who self-selected ESS were prospectively enrolled. The 22-item SinoNasal Outcome Test (SNOT-22) and Medical Outcomes Study Questionnaire Short-Form 6-D (SF-6D) health utility values scores were recorded. Using residence zip codes, a secondary analysis of patient exposure to PM <2.5 μm and <10 μm (PM2.5 and PM10, respectively) was performed for the month of surgery utilizing data from Environmental Protection Agency air quality monitors. Spearman's correlation coefficients (ρ), 95% confidence intervals (CIs), and effect estimates (β) were used to determine the magnitudes of association. Simple, multivariate regression analysis was also completed.

RESULTS

One hundred and seven patients from four geographically unique institutions across the US were enrolled with a follow-up of 6 months. Patients with higher peri-operative PM2.5 exposure had less improvement in their SNOT-22 scores after ESS compared to those with less exposure using both univariate analysis (ρ = 0.26, 95% CI: 0.08, 0.43; P  =  .01) and after covariate adjustment with multivariate analysis (B  =  1.06, 95% CI: 0.001, 2.14, P  =  .05). Similar associations were not found with SF-6D outcomes or with PM10 as an exposure of interest. No significant correlations were found between peri-operative PM levels and Lund-Kennedy endoscopy scores post-operatively.

CONCLUSION

Preliminary data from this pilot study reveal that PM exposure at the time of ESS may negatively associate with post-operative improvement in sinonasal quality-of-life. Larger, population-based studies with more standardized PM exposure windows are needed to confirm the clinical significance of the present findings.

Association between air pollution and skin cutaneous melanoma: A Mendelian randomization study

There has been a consistent and notable increase in the global prevalence of skin cutaneous melanoma (SKCM). Although genetic factors are closely associated with the occurrence and development of melanoma, the potential influence of environmental factors cannot be overlooked. The existing literature lacks a definitive consensus on the correlation between air pollution and the incidence rate of SKCM. This study seeks to investigate the causal relationship between air pollution, specifically focusing on particulate matter (PM) 2.5, PM2.5-10, PM10, and nitrogen oxides, and the risk of SKCM. A 2-sample Mendelian randomization (MR) method was applied, utilizing extensive publicly accessible genome-wide association studies summary datasets within European populations. The primary analytical method employed was the inverse variance weighted method. Supplementary methods, including the weighted median model, MR-Egger, simple model, and weighted model, were chosen to ensure robust analysis. Heterogeneity assessment was conducted using Cochran's Q test. To identify potential pleiotropy, both MR-Egger regression and the MR-PRESSO global test were employed. Additionally, a sensitivity analysis was performed using the leave-one-out method. The analysis revealed no statistically significant association between air pollution and SKCM risk, with specific findings as follows: PM2.5 (P = .485), PM2.5-10 (P = .535), PM10 (P = .136), and nitrogen oxides (P = .745). While some results exhibited heterogeneity, all findings demonstrated an absence of pleiotropy. This study did not find substantive evidence supporting a causal relationship between air pollution and the risk of SKCM within European populations. The comprehensive MR analysis, encompassing various pollutants, suggests that environmental factors such as air pollution may not be significant contributors to the development of SKCM.

Particulate matter exposure is associated with increased inflammatory cytokines and eosinophils in chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is thought to result from complex interactions between the host immune system, microbiota, and environmental exposures. Currently, there is limited data regarding the impact of ambient particulate matter ≤2.5 μm in diameter (PM2.5) in the pathogenesis of CRS, despite evidence linking PM2.5 to other respiratory diseases. We hypothesized that PM2.5 may result in differential cytokine patterns that could inform our mechanistic understanding of the effect of environmental factors on CRS.

METHODS

We conducted an analysis of data prospectively collected from 308 CRS patients undergoing endoscopic sinus surgery. Cytokines were quantified in intraoperative mucus specimens using a multiplex flow cytometric bead assay. Clinical and demographic data including zip codes were extracted and used to obtain tract-level income and rurality measures. A spatiotemporal machine learning model was used to estimate daily PM2.5 levels for the year prior to each patient's surgery date. Spearman correlations and regression analysis were performed to characterize the relationship between mucus cytokines and PM2.5. RESULTS: Several inflammatory cytokines including IL-2, IL-5/IL-13, IL-12, and 21 were significantly correlated with estimated average 6, 9, and 12-month preoperative PM2.5 levels. These relationships were maintained for most cytokines after adjusting for age, income, body mass index, rurality, polyps, asthma, and allergic rhinitis (AR) (p < .05). There were also higher odds of asthma (OR = 1.5, p = .01) and AR (OR = 1.48, p = .03) with increasing 12-month PM2.5 exposure. Higher tissue eosinophil counts were associated with increasing PM2.5 levels across multiple timeframes (p < .05).

CONCLUSIONS

Chronic PM2.5 exposure may be an independent risk factor for development of a mixed, type-2 dominant CRS inflammatory response.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Retinoic Acid Treatment Mitigates PM2.5-Induced Type 2 Inflammation: Insights into Modulation of Innate Immune Responses

Some studies have demonstrated the effects of particulate matter (PM) on chronic rhinosinusitis with nasal polyps (CRSwNP) development, as well as the therapeutic role of retinoic acid (RA) in nasal polypogenesis. However, the immunologic effect of PM in innate lymphoid cells (ILCs) and the exact mechanism of the therapeutic effect of RA remain unclear. Therefore, the present study investigated the effects of fine-dust-induced inflammation in CRSwNP and the mechanisms of the therapeutic effect of RA. PM2.5 exposure exacerbated pathological damage in the nasal mucosa of mice with nasal polyps (NP) via upregulation of type 2 inflammation. Additionally, PM2.5 exposure increased the expression of type 2 cytokines and epithelial-cell-derived cytokines (IL-33 and IL-25) significantly, as well as the ILC populations in human-NP-derived epithelial cells (HNECs). Moreover, RA supplementation significantly increased the expression of ILCreg in Lin-CD45+CD127+ cells, which in turn increased the levels of the anti-inflammatory cytokine IL-10. The findings suggest that PM2.5 exposures could aggravate the CRSwNP type 2 inflammation, and RA treatment may ameliorate fine-dust-induced inflammation by modulating the innate immune response.

Impact of particulate air pollution on airway injury and epithelial plasticity; underlying mechanisms

Air pollution plays an important role in the mortality and morbidity of chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Particulate matter (PM) is a significant fraction of air pollutants, and studies have demonstrated that it can cause airway inflammation and injury. The airway epithelium forms the first barrier of defense against inhaled toxicants, such as PM. Airway epithelial cells clear airways from inhaled irritants and orchestrate the inflammatory response of airways to these irritants by secreting various lipid mediators, growth factors, chemokines, and cytokines. Studies suggest that PM plays an important role in the pathogenesis of chronic airway diseases by impairing mucociliary function, deteriorating epithelial barrier integrity, and inducing the production of inflammatory mediators while modulating the proliferation and death of airway epithelial cells. Furthermore, PM can modulate epithelial plasticity and airway remodeling, which play central roles in asthma and COPD. This review focuses on the effects of PM on airway injury and epithelial plasticity, and the underlying mechanisms involving mucociliary activity, epithelial barrier function, airway inflammation, epithelial-mesenchymal transition, mesenchymal-epithelial transition, and airway remodeling.

The Relationship between Fine Particle Matter (PM2.5) Exposure and Upper Respiratory Tract Diseases

PM2.5 is one of the most harmful components of airborne pollution and includes particles with diameters of less than 2.5 μm. Almost 90% of the world's population lives in areas with poor air quality exceeding the norms established by the WHO. PM2.5 exposure affects various organs and systems of the human body including the upper respiratory tract which is one of the most prone to its adverse effects. PM2.5 can disrupt nasal epithelial cell metabolism, decrease the integrity of the epithelial barrier, affect mucociliary clearance, and alter the inflammatory process in the nasal mucosa. Those effects may increase the chance of developing upper respiratory tract diseases in areas with high PM2.5 pollution. PM2.5's contribution to allergic rhinitis (AR) and rhinosinusitis was recently thoroughly investigated. Numerous studies demonstrated various mechanisms that occur when subjects with AR or rhinosinusitis are exposed to PM2.5. Various immunological changes and alterations in the nasal and sinonasal epithelia were reported. These changes may contribute to the observations that exposure to higher PM2.5 concentrations may increase AR and rhinosinusitis symptoms in patients and the number of clinical visits. Thus, studying novel strategies against PM2.5 has recently become the focus of researchers' attention. In this review, we summarize the current knowledge on the effects of PM2.5 on healthy upper respiratory tract mucosa and PM2.5's contribution to AR and rhinosinusitis. Finally, we summarize the current advances in developing strategies against PM2.5 particles' effects on the upper respiratory tract.

Causal associations of immune cell phenotypes with migraine: A mendelian randomization study

The interaction between the immune system and the brain, crucial for blood-brain barrier integrity, is a potential factor in migraine development. Although there's evidence of a connection between immune dysregulation and migraine, a clear causal link has been lacking. To bridge this knowledge gap, we performed a two-sample Mendelian randomization (MR) analysis of 731 immune cell phenotypes to determine their causality with migraine, of which parameters included fluorescence, cell abundance, count, and morphology. Sensitivity and pleiotropy checks validated our findings. After applying a false discovery rate correction, our MR study identified 35 of 731 immune phenotypes with a significant causal link to migraine (p < 0.05). Of these, 24 showed a protective effect (inverse variance weighting : p < 0.05, odds ratio <1), and 11 were risk factors (inverse variance weighting : p < 0.05, odds ratio >1). Although limited by population sample size and potential population-specific genetic variations, our study uncovers a significant genetic link between certain immune cell markers and migraine, providing new insights into the disorder's pathophysiology. These discoveries are crucial for developing targeted biomarkers and personalized treatments. The research enhances our understanding of immune cells' role in migraine and may substantially improve patient outcomes and lessen its socio-economic impact.

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.

Intranasal delivery of Borneol/R8dGR peptide modified PLGA nanoparticles co-loaded with curcumin and cisplatin alleviate hypoxia in pediatric brainstem glioma which improves the synergistic therapy

Cisplatin (cis) is a first-line chemotherapeutic used for the treatment of intractable pediatric brainstem glioma (PBSG). Its therapeutic effect in PBSG is, however, critically challenged by the hypoxic microenvironment of the tumor and the presence of the blood brain barrier (BBB). Herein, we report on the intranasal administration of borneol (Bo)/R8dGR peptide modified PLGA based nanoparticles (NP) co-loaded with curcumin and cisplatin (cur/cis). We observed that borneol modification improved the brain penetration of the nanoparticles by reduction of the expression of ZO-1 and occludin in nasal mucosa, while the R8dGR peptide modification allowed the targeting of the NP through the binding on integrin αvβ3 receptors which are present on PBSG cells. Following intranasal administration, BoR-cur/cis-NP attenuated hypoxia in the PBSG microenvironment and reduced angiogenesis, which prolonged survival of GL261-bearing PBSG mice. Therefore, intranasal administration of BoR-cur/cis-NP, which deeply penetrate PBSG, is an encouraging strategy to attenuate hypoxia which potentiates the efficacy of cisplatin in the treatment of PBSG.

Association Between Particulate Matter Exposure and Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a relatively common inflammatory disease of the nasal and paranasal sinus mucosa. Several epidemiological studies have established an association between particulate matter (PM) and CRS. Based on those data, PM has emerged as an important environmental factor in the development of CRS. Recent research has investigated the mechanisms and treatment options for CRS caused by PM through cellular experimentation. Therefore, the authors would like to explain the definition of PM, present research investigating the relationship between PM and CRS, and summarize the involved mechanisms reported to date.

The Impact of Social Determinants and Air Pollution on Healthcare Disparities in Chronic Rhinosinusitis With Nasal Polyps

BACKGROUND/OBJECTIVE

Multiple factors affect healthcare disparities in chronic rhinosinusitis (CRS) with and without nasal polyps. These factors include access to care, economic burdens to treatment, and differences in air pollution and air quality. In this paper, we will discuss how socioeconomic status, race, and air pollution burden influence healthcare disparities in the diagnosis and treatment outcomes of chronic rhinosinusitis with nasal polyps (CRSwNP).

METHODS

A literature search was performed via PubMed for articles related to CRSwNP, healthcare disparities, race, socioeconomic status, and air pollution in September 2022. Original studies from 2016 to 2022, landmark articles, and systematic reviews were included. We summarized these articles to cohesively discuss factors contributing to healthcare disparities in CRSwNP.

RESULTS

Literary search produced 35 articles. Individual factors such as socioeconomic status, race, and air pollution influence CRSwNP severity and treatment outcomes. Correlations were noted with socioeconomic status, race, and air pollution exposure and CRS severity and post-surgical outcomes. Air pollution exposure was also associated with histopathologic changes in CRSwNP. Lack of access to care was a notable contributor to healthcare disparities in CRS.

CONCLUSION

Healthcare disparities in the diagnosis and treatment of CRSwNP differentially affect racial minorities and individuals of lower socioeconomic status. Increased air pollution exposure in areas of lower socioeconomic status is a compounding factor. Clinician advocacy for greater healthcare access and reductions in environmental exposures for patients, among other societal changes, may help improve disparities.

Climate change, the environment, and rhinologic disease

BACKGROUND

The escalating negative impact of climate change on our environment has the potential to result in significant morbidity of rhinologic diseases.

METHODS

Evidence based review of examples of rhinologic diseases including allergic and nonallergic rhinitis, chronic rhinosinusitis, and allergic fungal rhinosinusitis was performed.

RESULTS

The lower socioeconomic population, including historically oppressed groups, will be disproportionately affected.

CONCLUSIONS

We need a systematic approach to improve healthcare database infrastructure and funding to promote diverse scientific collaboration to address these healthcare needs.

Chinese Guideline on Allergen Immunotherapy for Allergic Rhinitis: The 2022 Update

In the last few decades, there has been a progressive increase in the prevalence of allergic rhinitis (AR) in China, where it now affects approximately 250 million people. AR prevention and treatment include allergen avoidance, pharmacotherapy, allergen immunotherapy (AIT), and patient education, among which AIT is the only curative intervention. AIT targets the disease etiology and may potentially modify the immune system as well as induce allergen-specific immune tolerance in patients with AR. In 2017, a team of experts from the Chinese Society of Allergy (CSA) and the Chinese Allergic Rhinitis Collaborative Research Group (C2AR2G) produced the first English version of Chinese AIT guidelines for AR. Since then, there has been considerable progress in basic research of and clinical practice for AIT, especially regarding the role of follicular regulatory T (TFR) cells in the pathogenesis of AR and the use of allergen-specific immunoglobulin E (sIgE) in nasal secretions for the diagnosis of AR. Additionally, potential biomarkers, including TFR cells, sIgG4, and sIgE, have been used to monitor the incidence and progression of AR. Moreover, there has been a novel understanding of AIT during the coronavirus disease 2019 pandemic. Hence, there was an urgent need to update the AIT guideline for AR by a team of experts from CSA and C2AR2G. This document aims to serve as professional reference material on AIT for AR treatment in China, thus improving the development of AIT across the world.

Environmental air pollution and chronic rhinosinusitis: A systematic review

Objective

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

Methods

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

Results

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

Conclusion

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

Level of Evidence

3a

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

Air Pollution Exposure and the Development of Chronic Rhinosinusitis in the Active Duty Population

INTRODUCTION

It has been shown that combat environment exposure, including burn pits that produce particulate matter 2.5 (PM2.5), is associated with lower respiratory tract disease in the military population with increased hypothetical risk of upper respiratory disease, but no study has been done that examines the effects of non-combat environmental exposures on the development of chronic rhinosinusitis (CRS) in the active duty population. The primary goal of this study is to evaluate how air pollution exposure correlates to the development of CRS in active duty service members in the United States.

METHODS

The military electronic medical record was queried for active duty service members diagnosed with CRS by an otolaryngologist between January 2016 and January 2018, who have never deployed, stationed in the United States from 2015 to 2018 (n = 399). For each subject, the 1-year mean exposure of PM2.5, particulate matter 10 (PM10), nitrogen dioxide (NO2), and ozone was calculated. The control group was comprised of the same criteria except these patients were diagnosed with cerumen impaction and matched to the case group by age and gender (n = 399). Pollution exposure was calculated based on the Environmental Protection Agency's data tables for each subject. Values were calculated using chi-square test for categorical variables and the Mann-Whitney U-test for continuous variables.

RESULTS

Matched cases and controls (n = 399) with 33.1% male showed a statistically significant odds ratio (OR) of 5.99 (95% CI, 2.55-14.03) for exposure of every 5 µg/m3 of PM2.5 increase and the development of CRS when controlling for age, gender, and diagnosis year. When further adjusting for smoking status, the OR was still statistically significant at 3.15 (95% CI, 1.03-9.68). Particulate matter 10, ozone, and NO2 did not show any statistical significance. Odds ratios remained statistically significant when further adjusting for PM10 and ozone, but not NO2. Dose-dependent curves largely did not show a statistical significance; however, they did trend towards increased exposure of PM2.5 leading to an elevated OR.

CONCLUSION

This study showed that PM2.5 exposure is a major independent contributor to the development of CRS. Exposure to elevated levels produced statistically significant odds even among smokers and remained significant when controlling for other measured pollutants. There is still much to be understood about the genesis of CRS. From a pollution exposure perspective, a prospective cohort study would better elucidate the risk of the development of CRS among those exposed to other pollutants.

Fine particulate matter exposure exacerbated nasal mucosal damage in allergic rhinitis mice via NLRP3 mediated pyroptosis

BACKGROUND

The incidence of nasal allergy/allergic rhinitis (AR) is rising worldwide, which has become a serious public health problem. Epidemiological studies point that exposure to environmental PM2.5 is closely linked to AR aggravation, however, the exactly mechanism is not clear. This study was performed to reveal molecular mechanisms of PM2.5 -induced AR deterioration.

METHODS

Morphology and element analysis of PM2.5 was examined by scanning electron microscopy (SEM) and Energy Dispersive Spectrometer (EDS). A total of 24 female C57BL/6 mice were divided into three groups (control group, AR group, and PM2.5 + AR group, each group contains 8 mice). Mice from AR group and PM2.5 + AR group were intraperitoneally injected with OVA suspension (0.004% OVA+3% aluminum hydroxide) on days 1, 7, and 14. 0.2 mL /kg B.W. for sensitization; then the same mice were intranasal instilled with 5% OVA solution daily for 7 days to established AR mice model (each nostril for 10 μl, day 15-21). The mice were intranasal instilled PBS (control group and AR group, each nostril for 10 μl) or PM2.5 (AR + PM2.5 group, 4.0 mg/kg b.w., each nostril for 10 μl) at the same way from day 23-29. The nasal symptoms were evaluated after the last instillation of PM2.5. Pathological changes and ultrastructure of nasal mucosa were observed by HE staining and SEM. Goblet cells hyperplasia was performed by Periodic acid-Schiff (PAS) staining. NLRP3, Caspase-1, GSDMD and IL-1β protein expression were assessed by immunohistochemical (IHC) staining.

RESULTS

Exposure to PM2.5 aggravated rhinitis symptom, promoted the secretion of serum IgE level and destroyed ultrastructural of nasal mucosa. Interestingly, NLRP3, Caspase-1 GSDMD and IL-1β protein expression were obviously elevated. NLRP3 /Capase-1/ GSDMD meditated cell pyroptosis participated in the process of AR exacerbation. However, macrophage is not the main effector cell.

CONCLUSION

PM2.5 exposure induces aggravation of allergic rhinitis, which is related to NLRP3 inflammasome meditated caspase-1 activation and cell pyroptosis in nasal mucosal.

Role of Environmental Air Pollution in Chronic Rhinosinusitis

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Ursolic Acid Alleviates Mucus Secretion and Tissue Remodeling in Rat Model of Allergic Rhinitis After PM2.5 Exposure

BACKGROUND

According to recent epidemiologic studies, exposure to fine particulate matter (particulate matter 2.5 ≤ µm [PM2.5]) in the air increases the incidence and severity of allergic rhinitis (AR). Ursolic acid (UA) has activities in immune regulation and anti-inflammatory. However, the role of UA intervention on PM2.5-exposed AR remains unknown. In this study, we investigated the effects of UA on tissue remodeling and mucus hypersecretion in a rat model of AR after PM2.5 exposure.

METHODS

AR was induced in rats with ovalbumin (OVA) and they were exposed to ambient PM2.5(200 µg/m3) via a PM2.5 inhalation exposure system for 30 days(ARE group). Ursolic acid intervention was administrated in the AR model after PM2.5 exposure (UA group). Hyperplasia of goblet cells was detected by periodic acid-Schiff (PAS) staining and collagen deposition in the nasal mucosa was detected by Masson trichrome (MT) staining.MUC5AC expression was measured by immunohistochemistry.

RESULTS

UA group showed reduced goblet cell hyperplasia and collagen deposition in the nasal mucosa which exacerbated after PM2.5 exposure, as reflected by PAS and MT staining when compared with the ARE group. Immunohistochemical results showed that the expression of MUC5AC in the UA group was lower than that in the ARE group.

CONCLUSION

Analysis of our data indicated that UA could attenuate nasal remodeling and mucus hypersecretion in aggravation of AR after PM2.5 exposure, which may be the pathophysiologic mechanisms for the prevention of AR exacerbated by exposure to PM2.5.

Epithelial-to-mesenchymal transition in neutrophilic chronic rhinosinusitis

PURPOSE OF REVIEW

Barrier dysfunction, tissue fibrosis, and remodeling are essential processes of the pathophysiology of chronic rhinosinusitis (CRS). The role of epithelial-to-mesenchymal transition (EMT) has been assessed in various studies in CRS. In this review, we summarized the pathophysiologic mechanisms of EMT related to CRS, particularly neutrophilic CRS.

RECENT FINDINGS

Loss of epithelial characteristics due to EMT makes leaky epithelium, and transformed mesenchymal cells cause fibrosis and remodeling. Hypoxia, allergens (house dust mites), infections, and air pollutants were related to the pathogenesis of neutrophilic CRS, and these factors are known to induce barrier dysfunction and EMT in sinonasal epithelia. Some molecular pathways related to EMT have been recognized in CRS, including interferon-γ/p38/extracellular signal-regulated kinase, high-mobility group box 1/receptor of advanced glycosylation end-products, TGF-β1/SMAD, and Wnt/β-catenin-signaling pathways. Apart from, several microRNAs (miR-21, miR-761, and miR-30a-5p) have been identified to regulate EMT in CRS.

SUMMARY

EMT is considered to be an important pathogenesis mechanism for CRS. The factors cause EMT in CRS, and the associated molecular mechanisms are related to neutrophilic inflammation. Further studies on CRS endotype and/or phenotype are needed to clarify the implication of EMT on CRS pathogenesis.

Ammonia exposure causes lung injuries and disturbs pulmonary circadian clock gene network in a pig study

Ammonia toxicity to respiratory system in pig faming is of particular concern, but the molecular mechanism remains still unclear. The present study was devoted to assess the impacts of the ammonia exposure on the lung tissues based on a pig study using 80 ppm ammonia exposing to piglets for different days. The histology analysis revealed ammonia exposure induced lung injury and inflammatory response, as indicated by epithelial-mesenchymal transition (EMT), significant thickening of alveolar septa, infiltration of inflammatory cells and excessive mucus production. The transcriptome analysis revealed many more up-regulated genes in exposure groups when compared with the control group, and these genes were significantly enriched in the GO term of extracellular exosome, proteolysis, and regulation of circadian rhythm. The study discovered the induction of seven genes (CRY2, CIART, CREM, NR1D1, NR1D2, PER1 and PER3) that encode repressors of circadian clock. One gene (ARNTL) that encodes activator of circadian clock was down-regulated after ammonia exposure. The results of this study suggest that ammonia exposure disturbed the pulmonary circadian clock gene expression, which may establish new evidence for further understanding the toxicity of ammonia to lungs.

Effects of Ursolic Acid on the Expression of Th1-Th2-related Cytokines in a Rat Model of Allergic Rhinitis After PM2.5 Exposure

BACKGROUND

Allergic rhinitis (AR) is a global health problem and closely related to environmental factors. Ursolic acid (UA) has potential in the treatment of allergic inflammation. The effects of UA intervention on PM2.5-induced AR remain uncertain.

OBJECTIVE

To assess the effects of UA on nasal symptoms and the expression of T-helper (Th)1-Th2-related cytokines in a rat model of AR after fine particulate matter (particulate matter ≤ 2.5 µm [PM2.5]) exposure.

METHODS

A total of 40 healthy female Sprague-Dawley rats were randomly divided into 4 groups: normal control group (NC group), ovalbumin (OVA)- induced AR model (AR group), PM2.5-exposed AR group exposed to 200 g/m3 PM2.5 for 30 days via inhalation (ARE group), and a group with UA intervention to the AR model after PM2.5 exposure (UA group). UA intervention was adopted after PM2.5 exposure in the UA group. Nasal symptoms and levels of Th1-Th2 cytokines in the serum were detected in each individual rat. The pathological changes and expression of Eotaxin in the nasal mucosa of each individual rat were examined by histology.

RESULTS

PM2.5 significantly increased the number of sneezes and nasal rubs in the rats with AR, and UA alleviated these symptoms. UA decreased interleukin (IL)-4, IL-5, IL-13, Eotaxin-1, and OVA Immunoglobulin E (IgE) protein levels. In the AR group, hematoxylin and eosin staining showed disordered arrangement of the nasal mucosa epithelium, cell shedding, eosinophilic infiltration, swelling of the glands, and submucosal vascular congestion. UA group showed reduced eosinophilic infiltration and orderly arrangement of the mucosal epithelium when compared with the ARE group. Immunohistochemical results showed that the expression of Eotaxin in the UA group was lower than that in the ARE group.

CONCLUSION

UA could relieve nasal symptoms caused by PM2.5 exposure, the possible mechanism of which is to inhibit the expression of Th2 cytokines, eosinophilic infiltration, and specific IgE production.

Investigation of the impact of PM2.5 on the ciliary motion of human nasal epithelial cells

Nasal epithelium provides a physical barrier to potentially harmful stimuli. Cilia, which is on the apical side of the human nasal epithelial cells (HNEpCs), plays a critical role in removing inhaled harmful matter. Ciliary beat frequency (CBF) and ciliary beat pattern (CBP) are the two important indicators for ciliary beat function. However, impacts of the fine particulate matter (PM_2.5) on CBF and CBP are still unknown. We aimed to evaluate the impact of PM_2.5 on the ciliary beat function of the HNEpCs and its potential mechanisms. After exposed to PM_2.5 for 12 h, cilia of HNEpCs were in disordered arrangement. The ciliary coverage rate was decreased after PM_2.5 exposure of a series of concentration, while the proportion of basal cells was continuously increased and could be observed on the apical side of the HNEpCs which is hardly be observed without PM_2.5 exposure. PM_2.5 increased the CBF after 12 h exposure, while 24 h exposure increased the CBF at the relative lower dosage groups and then made a decrease at relative higher dosage groups. CBF were classified into two different types, which had different changes following PM_2.5 exposure. CBP showed significant changes characterized as the increased dyskinesia index. Total levels of cellular ATP and the mitochondrial membrane potential were decreased following 12 h exposure of PM_2.5, while no change was found in O₂ consumption. In conclusion, PM_2.5 impact the ciliary beat function of HNEpCs, and the mitochondrial dysfunction might play an important role in it.