Cigarette smoke inhibits nasal airway epithelial cell growth and survival

Air Quality, Allergic Rhinitis, and Asthma

This review article highlights air pollution as a critical global health concern with emphasis on its effects and role in the development and exacerbation of upper airway and lower airway disease with a focus on allergic rhinitis and asthma. This review underscores the World Health Organization's recognition of air pollution as the biggest environmental threat to human health. It discusses the various components and categories of air pollutants and the evidence-based effects they have on asthma and allergic rhinitis, ranging from pathogenesis to exacerbation of these conditions across various age groups in different geographic locations.

Causal relationships between potential risk factors and chronic rhinosinusitis: a bidirectional two-sample Mendelian randomization study

PURPOSE

Smoking, alcohol consumption, allergic rhinitis (AR), asthma, and obesity are associated with chronic rhinosinusitis (CRS), albeit the causal relationships between them remain elusive. Therefore, we conducted a bidirectional two-sample Mendelian randomization (MR) study to investigate the bidirectional causal effects between these potential risk factors and CRS.

METHODS

The data for daily cigarette consumption, age of smoking initiation, weekly alcohol consumption, AR, asthma, body mass index (BMI), and CRS were drawn from large sample size genome-wide association studies. Single-nucleotide polymorphisms associated with each exposure were considered instrumental variables in this study. We investigated causal effects by using the inverse-variance weighted (IVW) method with random effects, and weighted median and MR-Egger methods were used for sensitivity analyses. Pleiotropic effects were detected and corrected by the MR pleiotropy residual sum and outlier test and MR-Egger model.

RESULTS

We found the causal effects of daily cigarette consumption (IVW, OR = 1.15, 95% CI 1.00-1.32, p = 0.046), AR (IVW, OR = 4.77, 95% CI 1.61-14.13, p = 0.005), asthma (IVW, OR = 1.45, 95% CI 1.31 - 1.60, p < 0.001), and BMI (IVW, OR = 1.05, 95% CI 1.00-1.09, p = 0.028) on CRS. Furthermore, we found a causal effect of CRS on asthma (IVW OR = 1.08, 95% CI 1.05-1.12, p < 0.001).

CONCLUSIONS

We confirmed the causal effects of daily cigarette consumption, AR, asthma, and BMI on CRS, and the causal effect of CRS on asthma, while no causal relationship between age of smoking initiation, weekly alcohol consumption, and CRS was found. These findings are expected to provide high-quality causal evidence for clinical practice and the pathogenesis of CRS and asthma.

Tobacco Use Increases the Adjusted Risk of Revision Endoscopic Sinus Surgery in Patients With Chronic Rhinosinusitis

BACKGROUND

Large epidemiologic studies have suggested that a history of tobacco use may be associated with an increased risk of developing chronic rhinosinusitis (CRS). The impact of tobacco use on revision rates of endoscopic sinus surgery (ESS), however, remains limited.

OBJECTIVE

This study seeks to define the independent risk of tobacco use (active or prior) on revision rates of ESS among a large cohort of patients with CRS.

METHODS

A state population database was queried for patients age ≥18 years with CRS who underwent at least one ESS between 1996 and 2018. Demographic characteristics, history of ESS, and tobacco use status were compared across patients with CRS, using t tests for continuous variables and χ² tests for categorical variables. Unadjusted and adjusted logistic regression models were used to understand the impact of tobacco status on revision surgery.

RESULTS

The final analysis included 34 350 patients (29 916 CRS with no revision surgery and 4434 CRS with revision surgery). Unadjusted regression analysis demonstrated an increased odds of undergoing revision ESS (OR 1.12, 95% CI: 1.00-1.25, P = .05) among males with a history of tobacco use and CRS. Adjusted regression analysis demonstrated that the risk of revision ESS among CRS patients with a history of asthma and tobacco use was 1.72-fold, while the risk among CRS patients who were tobacco users without asthma was 1.11-fold.

CONCLUSION

History of tobacco use is an independent risk factor for revision ESS among patients with CRS.

Effect of e-cigarettes on nasal epithelial cell growth, Ki67 expression, and pro-inflammatory cytokine secretion

OBJECTIVE

Upon use, e-cigarette aerosol comes in contact with various mucosal tissues, including the nasal epithelium, which may lead to nasal pathologies. We therefore assessed the effect of e-cigarettes on nasal epithelial cell and tissue behaviours.

METHODS

Human primary nasal epithelial cells and engineered 3D nasal mucosa tissues were exposed or not to either e-cigarette aerosol or standard cigarette smoke. We then evaluated cell viability and lactate dehydrogenase (LDH) activity. With the tissues analysed tissue structure, the expression of Ki67 proliferating marker, and the secretion of pro-inflammatory cytokines by the engineered nasal mucosa.

RESULTS

The nasal epithelial cells exposed to e-cigarettes displayed a larger cell size and a faint nucleus following exposure to e-cigarettes. This is supported by the increased levels of LDH activity following exposure to e-cigarettes, compared to that observed in the control. Tissues exposed to e-cigarette aerosol displayed a structural deregulation, with more large-sized cells, fewer Ki67-positive cells, and a reduced proliferation rate, compared to that observed in the non-exposed tissues. Cytokine measurements showed high levels of IL-6, IL-8, TNFα, and MCP-1, demonstrating that e-cigarettes activated pro-inflammatory cytokine responses.

CONCLUSION

E-cigarette aerosol showed adverse effects on nasal epithelial cells and nasal engineered mucosa tissue. These findings indicate that e-cigarettes could be a threat to nasal tissues and may impair the innate immune function of nasal epithelial cells.

Aeroallergens, air pollutants, and chronic rhinitis and rhinosinusitis

Chronic rhinitis and rhinosinusitis are among the most common conditions worldwide with significant morbidity and decreased quality of life. Although the pathogenesis of these conditions is multifactorial, there has been increasing evidence for the role of environmental factors such as aeroallergens and air pollutants as initiating or exacerbating factors. This review will outline the current literature focusing on the role of aeroallergens and air pollution in the pathogenesis of chronic sinonasal inflammatory conditions.

A Systematic Review of the Association between Cigarette Smoke Exposure and Chronic Rhinosinusitis

Objectives Cigarette smoking and passive smoke exposure have been associated with chronic rhinosinusitis (CRS). Our goal in this systematic review was to (1) determine if there was a strong correlative effect in large population studies between cigarette smoke exposure and the prevalence of CRS, (2) investigate pathogenic mechanisms of cigarette smoke in the upper airway, and (3) determine if a history of cigarette smoking affects the medical and surgical outcomes of CRS. Data Sources MEDLINE, Embase, Cochrane CENTRAL, Web of Science SCI and CPCI-S, and websites. Methods A comprehensive literature review and quantitative meta-analysis of studies based on the PRISMA protocol and examining the relationship between cigarette smoke exposure and CRS was performed. A search strategy was developed using various terms such as sinusitis, rhinitis, rhinosinusitis, and smoking. The articles were categorized by (1) epidemiology, (2) pathophysiology, and (3) outcomes. Data regarding study design, population/setting, methods, and bias were collected. Results The initial search generated 2621 titles/abstracts with 309 articles undergoing secondary review and 112 articles for final review. We determined that there is a strong correlation between active and passive cigarette smoke with the prevalence of CRS. Cigarette smoke challenge to sinonasal epithelia results in the release of inflammatory mediators and altered ciliary beat frequency. Pediatric patients exposed to secondhand smoke appear to have particularly poor outcomes. Conclusion There is clear evidence that cigarette smoke is related to CRS, but longitudinal and mechanistic studies are required to determine a causative effect. This information is critical for greater understanding of CRS health outcomes.

Risk Factors and Comorbidities in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogeneous disorder that creates a significant burden on the healthcare system. It is caused by a combination of inflammatory, environmental, and host factors; however, the precise mechanism of how each factor leads to CRS continues to be a source of debate. Previous data regarding this topic is often inconsistent or of lower quality. In this article, we review the recent literature on the risk factors and comorbidities in CRS. Large population-based studies have helped establish smoking as a significant risk factor for CRS. The focus has now shifted towards smoking and its effect on long-term outcomes after endoscopic sinus surgery (ESS). Ciliary dyskinesia, both primary and secondary, can affect both the sinonasal cavity and lower airways simultaneously by decreasing the beat frequency of cilia and inducing mucostasis. The effects of secondary dyskinesia may be reversible and there is some evidence to suggest the use of topical mucolytics in patients with CRS. Allergy and variants of sinonasal anatomy have been hypothesized to increase the risk of developing CRS by inducing chronic inflammation and obstructing the sinus ostia. Nevertheless, emerging data regarding these topics continue to produce inconclusive results. Inflammation of the upper and lower airways can occur simultaneously as seen in patients with asthma and aspirin sensitivity. The connection between these pro-inflammatory disease states has been known for many years. Newer evidence include large population-based studies and studies that correlate objective tests, such as computer tomography scans to pulmonary function tests. However, the treatment of CRS and its effects on obstructive airway disease continues to be a topic of debate. More large prospective studies are needed in order to continue refining our knowledge of the disease processes in CRS.

Pulmonary function in never-smoker patients with chronic rhinosinusitis

BACKGROUND

A close relationship between upper and lower respiratory tract diseases has been reported. The purpose of this study was to evaluate lung function in patients with chronic rhinosinusitis (CRS) who have never smoked.

METHODS

A total of 208 patients with CRS were enrolled in this study. Of these subjects, 96 patients were ever smokers and 112 patients were never smokers. CRS patients with lower pulmonary diseases including chronic obstructive pulmonary disease (COPD) and asthma were excluded from this study. Age-matched normal control subjects (n = 55) who were never smokers were also recruited. Pulmonary function testing was performed using spirometry. Lund-Mackay computed tomography (CT) score, peripheral blood eosinophil count, and immunoglobulin E (IgE) level in serum samples were examined. Nasal obstruction was evaluated by active anterior rhinomanometry.

RESULTS

CRS patients who were ever smokers have decreased lung function. Never-smoking patients with CRS also showed significant obstructive lung function changes as compared with normal controls. No significant correlation was detected between the clinical parameters (CT score, eosinophil count, IgE level, and nasal resistance) and lung function.

CONCLUSION

Asymptomatic obstructive lung function changes were observed in never-smoking patients with CRS. Our findings suggest that patients with CRS should be followed carefully in order to detect lung diseases.

Constitutive expression of vascular endothelial cell growth factor (VEGF) gene family ligand and receptors on human upper and lower airway epithelial cells

BACKGROUND

We previously reported that vascular endothelial cell growth factor (VEGF) is abundantly expressed by primary human nasal epithelial cells (PNECs) and functions to promote cell hyperplasia in polyposis. Therefore, we aimed to examine the full expression profile of other members of the VEGF gene family of ligands and receptors, which may play a role in cell growth and the development of chronic rhinosinusitis with nasal polyposis (CRSwNP).

METHODS

Messenger RNA (mRNA) and protein expression of VEGF genes, receptors, and co-receptors was examined from cultured PNECs (n = 4) and compared to that from primary human bronchial epithelial cells (PBECs; n = 4) and the BEAS2B cell line (n = 4) by real-time polymerase chain reaction (PCR) and flow cytometry.

RESULTS

We report abundant expression of VEGFA, VEGFB, and VEGFC, detected by mRNA and flow cytometric analysis on PNECs. We herein report the novel finding that there is significant expression of VEGFR1, VEGFR2, VEGFR3, and both neuropilin co-receptors, NP1 and NP2, at baseline conditions on PNECs. Lower airway PBECs and BEAS2B cells displayed similar patterns of expression.

CONCLUSION

PNECs express high constitutive levels of the VEGF gene family homolog of ligands and receptors. Expression of multiple VEGF ligand-receptor combinations may function as redundant pathways to promote upper and lower airway epithelial cell growth during inflammation.

Expression of semaphorin 3A and neuropilin 1 in asthma

Neuropilin 1 (NP1) is a part of essential receptor complexes mediating both semaphorin3A (SEMA3A) and vascular endothelial growth factor (VEGF) which is one of important mediators involved in the pathogenesis of asthma. Therefore, it is possible that SEMA3A plays a role in the pathogenesis of asthma through attenuation of VEGF-mediated effects. In the present study, we aimed to evaluate expression levels of SEMA3A and NP1 using induced sputum of asthmatics and a murine model of asthma. Firstly, SEMA3A and NP1 expressions in induced sputum of asthmatics and SEMA3A and NP1 expression on bronchoalveolar lavage (BAL) cells and lung homogenates of asthmatic mice were determined. Then we evaluated the immunolocalization of VEGF receptor 1 (VEGFR1), VEGF receptor 2 (VEGFR2), and NP1 expressions on asthmatic mice lung tissue and their subcellular distributions using fibroblast and BEAS2B cell lines. Sputum SEMA3A and NP1 expressions were significantly higher in asthmatics than controls. Similarly, SEMA3A and NP1 expressions on BAL cells and lung homogenates were significantly elevated in asthmatic mice compared to control mice. Immunohistochemical analysis showed that VEGFR1, VEGFR2, and NP1 expressions were also uniformly increased in asthmatic mice. Our observations suggest that SEMA3A and NP1 may play important roles in the pathogenesis of asthma.