Effects of cigarette smoking on mucin production in human middle ear epithelial cells

ABO blood type correlates with risk and protective factors for chronic suppurative otitis media

BACKGROUND

ABO blood type associated with differentiated onset of infectious diseases.

AIMS/OBJECTIVE

To investigate whether people with different blood types were vulnerable in developing chronic otitis media (CSOM) and if the risk and protective factors varied among them.

MATERIAL AND METHODS

The study was a case-control study that included 206 participants in the case group and 210 in the control group. Stratified analysis for blood type was adopted.

RESULTS

Patients with different blood types were insignificantly different in the incidence of CSOM. Upper respiratory tract infection (URTI, OR = 21.81, 95% CI: 4.80-99.06), socioeconomic status (OR = 3.02, 95% CI: 1.35-6.74), and were risk factors in blood type A. In blood type B, smoking and urban residence were risk factors. The OR (95% CI) were 11.42 (2.77-47.08), and 0.14 (0.03-0.65). Urban residence, BMI and blood calcium increase, male gender were protective factors for different blood types.

CONCLUSIONS AND SIGNIFICANCE

Our study identified the risk and protective factors for CSOM among different blood types. The findings might provide new insights into taking precautions against CSOM in people of different blood types.

Association between asthma or chronic obstructive pulmonary disease and chronic otitis media

We hypothesized that asthma/chronic obstructive pulmonary disease (COPD) might increase the risk of chronic otitis media (COM), as asthma or COPD affects other diseases. The aim of this research was to investigate whether the incidence of COM is affected by a diagnosis of asthma or COPD in patients compared to matched controls from the national health screening cohort. A COM group (n = 11,587) and a control group that was 1:4 matched for age, sex, income, and residence area (n = 46,348) were selected. The control group included participants who never received treatment for COM from Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2015. The crude and adjusted odds ratios (ORs) of previous asthma/COPD before the index date for COM were analyzed using conditional logistic regression. The analyses were stratified by age, sex, income, and region of residence. The period prevalence of asthma (17.5% vs. 14.3%, p < 0.001) and COPD (6.6% vs. 5.0%, p < 0.001) were significantly higher in the COM group than in the control group. In addition, the odds of asthma and COPD were significantly higher in the COM group than in the control group. Both asthma (adjusted OR 1.23, 95% confidence interval [CI] 1.16-1.31, p < 0.001) and COPD (adjusted OR 1.23, 95% CI 1.13-1.35, p < 0.001) increased the ORs for COM. This positive association between asthma/COPD and COM indicates that asthma/COPD might increase the incidence of COM.

Changes in Eustachian Tube Mucosa in Mice After Short-Term Tobacco and E-cigarette Smoke Exposure

OBJECTIVES

To evaluate histologic changes in middle ear and eustachian tube (ET) mucosa of mice after exposure to tobacco or electronic cigarette (e-cigarette) smoke. To determine whether there were any mitigating effects of middle ear application of anti-IL-13 or the epidermal growth factor receptor antagonist AG1478 on noted changes within ET mucosa.

STUDY DESIGN

Controlled animal study.

METHODS

Fifty BALB/cJ mice were randomly assigned to one of five groups: A control group with no smoke exposure, two groups exposed to tobacco smoke, and two groups exposed to e-cigarette vapor. Within the exposed groups after 4 weeks of exposure, one ear was infiltrated with a saline hydrogel and the other ear with hydrogel of either Anti-IL-13 or AG1478. After four more weeks of exposure, the animals were euthanized and the ETs were evaluated for mucosal changes.

RESULTS

Compared to control animals with no smoke exposure, there were significant decreases in the numbers of goblet cells within the ET mucosa of mice exposed to tobacco smoke and e-cigarette vapor. No significant differences in cilia, mucin, or squamous metaplasia were noted. Neither anti-IL-13 nor AG178 significantly altered goblet cell count in the ET mucosa of mice exposed to tobacco smoke; however, both agents significantly increased goblet cells within the ET mucosa of mice exposed to e-cigarette vapor.

CONCLUSION

Short-term tobacco smoke and e-cigarette vapor significantly decrease goblet cell count in mouse ET mucosa. Middle ear application of both anti-IL-13 and AG1478 resulted in an increase in goblet cell count among mice exposed to e-cigarette vapor, but not to tobacco smoke.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.

RNA Sequencing and Pathways Analyses of Middle Ear Epithelia From Patients With Otitis Media

OBJECTIVES

Otitis media (OM) is the most common pediatric diagnosis in the United States. However, our understanding of the molecular pathogenesis of OM remains relatively poor. Investigation of molecular pathways involved in OM may improve the understanding of this disease process and elucidate novel therapeutic targets. In this study, RNA sequencing (RNA-Seq) was used to discern cellular changes associated with OME compared to healthy middle ear epithelium (MEE).

STUDY DESIGN

Ex vivo case-control translational.

METHODS

Middle ear epithelia was collected from five pediatric patients diagnosed with OME undergoing tympanostomy tube placement and five otherwise healthy pediatric patients undergoing cochlear implantation. Specimens underwent RNA-Seq and pathways analyses.

RESULTS

A total of 1,292 genes exhibited differential expression in MEE from OME patients compared to controls including genes involved in inflammation, immune response to bacterial OM pathogens, mucociliary clearance, regulation of proliferation and transformation, and auditory cell differentiation. Top networks identified in OME were organismal injury and abnormalities, cell morphology, and auditory disease. Top Ingenuity canonical pathways identified were axonal guidance signaling, which contains genes associated with auditory development and disease and nicotine degradation II and III pathways. Associated upstream regulators included β-estradiol, dexamethasone, and G-protein-coupled estrogen receptor-1 (GPER1), which are associated with otoprotection or inflammation during insult.

CONCLUSIONS

RNA-Seq demonstrates differential gene expression in MEE from patients with OME compared to healthy controls with important implications for infection susceptibility, hearing loss, and a role for tobacco exposure in the development and/or severity of OME in pediatric patients.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Comparison between in vitro toxicities of tobacco- and menthol-flavored electronic cigarette liquids on human middle ear epithelial cells

Since electronic-cigarettes (e-cigarettes) are considered less toxic than conventional tobacco smoking, the use of e-cigarettes has increased, and the market for e-cigarette liquids (e-liquids) is continuously increasing. However, many studies showed that e-cigarettes may cause various harmful effects in lung, oral and heart. In this study, we investigated the effects of e-liquids on otitis media (OM) using human middle ear epithelial cells (HMEECs). Menthol-flavored e-liquid induced significant cell death in HMEECs (IC50: 1.45 ± 0.14%) and tobacco-flavored e-liquid led to increase in inflammatory cytokine levels and higher mucin production. Flavored e-liquids decreased the mRNA levels of genes encoding epithelial sodium channels (ENaCs) in HMEECs. Apoptosis and autophagy reactions were induced by exposure of HMEECs to menthol- and tobacco-flavored e-liquids. Tobacco-flavored e-liquids caused a greater increase in the levels of autophagosome marker, LC3-II, compared to menthol-flavored e-liquids, which was followed by cell death. These results demonstrate that flavored e-liquids cause cytotoxicity via apoptosis, autophagy, inflammatory response, and mucin production in HMEECs. The flavors present in e-liquids might be a risk factor for the development of otitis media.

Ramifications of secreted mucin MUC5AC in malignant journey: a holistic view

Heavily glycosylated secreted mucin MUC5AC, by the virtue of its cysteine-rich repeats, can form inter- and intramolecular disulfide linkages resulting in complex polymers, which in turn craft the framework of the polymeric mucus gel on epithelial cell surfaces. MUC5AC is a molecule with versatile functional implications including barrier functions to epithelial cells, host-pathogen interaction, immune cell attraction to sites of premalignant or malignant lesions and tumor progression in a context-dependent manner. Differential expression, glycosylation and localization of MUC5AC have been associated with a plethora of benign and malignant pathologies. In this era of robust technologies, overexpression strategies and genetically engineered mouse models, MUC5AC is emerging as a potential diagnostic, prognostic and therapeutic target for various malignancies. Considering the clinical relevance of MUC5AC, this review holistically encompasses its genomic organization, domain structure, glycosylation patterns, regulation, functional and molecular connotation from benign to malignant pathologies. Furthermore, we have here explored the incipient and significant experimental tools that are being developed to study this structurally complex and evolutionary conserved gel-forming mucin.

Factors affecting the outcome of adenoidectomy in children treated for chronic otitis media with effusion

OBJECTIVE

The aim of this cohort was to determine potential risk factors, concerning the effectiveness of adenoidectomy in the treatment of chronic otitis media with effusion in children.

METHODS

Ninety six children with chronic otitis media with effusion treated with adenoidectomy were enrolled in this study. A thorough medical history was taken, including family history of otologic disease, parental smoking habits and breast feeding history. Radiographic palatal airway size was measured preoperatively, whereas the presence of allergy was also investigated. All patients were, postoperatively, followed up for a period of two years, in three month intervals. Disease course was classified as "complete remission", "improvement" or "consistence", in every postoperative evaluation, according to strictly established criteria.

RESULTS

Children's age proved to be a significant factor in the postoperative outcome of adenoidectomy, as a treatment of chronic otitis media with effusion, especially when comparing patients being over and under the fifth year of age. Also, the presence of allergy, family history of otologic disease and palatal airway size, all proved to influence postoperative outcome in a statistical significant way (p<0.05). On the other hand, child's sex, passive smoking, breast feeding and previous acute otitis media infections did not seem to alter the efficacy of adenoidectomy.

CONCLUSION

Adenoidectomy remains a cornerstone in the treatment of chronic otitis media with effusion in children. Results document that young age, presence of allergy predisposition, otologic family history and small palatal airway can be important drawbacks and should be intensively sought for and taken into account, during treatment planning.

Air Pollution and Otitis Media in Children: A Systematic Review of Literature

Young children are particularly vulnerable to otitis media (OM) which globally affects over 80% of children below the age of 3 years. Although there is convincing evidence for an association between environmental tobacco smoke exposure and OM in children, the relationship with ambient air pollution is not clear. We aimed to systematically review the literature on the relationship between ambient air pollution exposure and OM in children. A systematic search was performed in PubMed and EMBASE databases. Of 934 references identified, 24 articles were included. There is an increasing body of evidence supporting an association between higher ambient air pollution exposure and a higher risk of OM in children. While NO₂ showed the most consistent association with OM, other specific pollutants showed inconsistent associations. Studies were mainly conducted in high/middle income countries with limited evidence from low-income countries. Although there was a general consensus that higher air pollution exposure is associated with a greater prevalence of OM, the evidence for associations with specific pollutants is inconsistent. More well-designed studies on associations between specific air pollutants as risk factors for OM are warranted, especially in low income countries with high air pollution levels.

Etiological factors associated with chronic suppurative otitis media in a population of Han adults in China

OBJECTIVE

Risk factors for chronic suppurative otitis media (CSOM) were not clearly established. The study was to investigate the etiological factors for CSOM from a population of Han adults in China.

METHODS

A case-control study was conducted at Second Affiliated Hospital of Xi'an Jiaotong University, School of Medicine in China. A total of 416 individuals participated in this study, which included 206 cases and 210 controls.

RESULTS

Multivariate logistic regression analysis revealed male (OR = 0.42; 95% CI: 0.21-0.83), BMI increasing (OR = 0.85; 95% CI: 0.77-0.93), URTI (OR = 152.85; 95% CI: 34.11-684.93), smoke/passive smoke (OR = 7.11; 95% CI: 3.36-15.07), residential location (urban area) (OR = 0.27; 95% CI: 0.13-0.56), serum calcium increasing (OR = 0.09; 95% CI: 0.01-0.71) were prime risk factors for CSOM. Univariate analysis revealed that low socioeconomic status (OR= 2.33; 95% CI: 1.57-3.45) and hepatitis B (OR = 4.90; 95% CI: 1.82-13.21) were risk factors together with the above variables.

CONCLUSION

This study has identified several variables as risk factors for CSOM, suggesting better healthcare, living condition, as well as better nutrition might decrease the development of CSOM. Further studies are necessary to assess the outcome of CSOM after interventions in the etiological factors.

Asian Sand Dust Enhances the Inflammatory Response and Mucin Gene Expression in the Middle Ear

Objectives.

Asia sand dust (ASD) is known to cause various human diseases including respiratory infection. The aim of this study was to examine the effect of ASD on inflammatory response in human middle ear epithelial cells (HMEECs) in vitro and in vivo.

Methods.

Cell viability was assessed using the cell counting kit-8 assay. The mRNA levels of various genes including COX-2, TNF-a, MUC 5AC, MUC 5B, TP53, BAX, BCL-2, NOX4, and SOD1 were analyzed using semiquantitative realtime polymerase chain reaction. COX-2 protein levels were determined by western blot analysis. Sprague Dawley rats were used for in vivo investigations of inflammatory reactions in the middle ear epithelium as a result of ASD injection.

Results.

We observed dose-dependent decrease in HMEEC viability. ASD exposure significantly increased COX-2, TNF-a, MUC5AC, and MUC5B mRNA expression. Also, ASD affected the mRNA levels of apoptosis- and oxidative stress-related genes. Western blot analysis revealed a dose-dependent increase in COX-2 production. Animal studies also demonstrated an ASD-induced inflammatory response in the middle ear epithelium.

Conclusion.

Environmental ASD exposure can result in the development of otitis media.

Effect of urban particles on human middle ear epithelial cells

OBJECTIVES

The aim of this study was to examine the cytotoxic effect and inflammatory response of human middle ear epithelial cells (HMEECs) induced by urban particles (UP).

MATERIALS AND METHODS

Cell viability following UP exposure was assessed in HMEECs using the CCK 8 assay. The expression levels of the inflammation-related genes (COX-2 and MUC5AC) were analyzed using semi-quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and COX-2 production was analyzed using western blotting.

RESULTS

Treatment with UP decreased cell viability in HMEECs in a dose- and time-dependent manner. UP exposure induced the significantly increased expression of COX-2 and MUC5AC. Western blotting showed dose dependently increased expression of COX-2 production.

CONCLUSIONS

UP decreased cell viability, increased the inflammatory response, and increased mucin gene production in HMEECs. These findings indicate that exposure to UP can contribute to the development of otitis media.

Genetic and functional evidence for a locus controlling otitis media at chromosome 10q26.3

BACKGROUND

Otitis media (OM) is a common childhood disease characterised by middle ear effusion and inflammation. Susceptibility to recurrent acute OM and chronic OM with effusion is 40-70% heritable. Linkage studies provide evidence for multiple putative OM susceptibility loci. This study attempts to replicate these linkages in a Western Australian (WA) population, and to identify the etiological gene(s) in a replicated region.

METHODS

Microsatellites were genotyped in 468 individuals from 101 multicase families (208 OM cases) from the WA Family Study of OM (WAFSOM) and non-parametric linkage analysis carried out in ALLEGRO. Association mapping utilized dense single nucleotide polymorphism (SNP) data extracted from Illumina 660 W-Quad analysis of 256 OM cases and 575 controls from the WA Pregnancy Cohort (Raine) Study. Logistic regression analysis was undertaken in ProbABEL. RT-PCR was used to compare gene expression in paired adenoid and tonsil samples, and in epithelial and macrophage cell lines. Comparative genomics methods were used to identify putative regulatory elements and transcription factor binding sites potentially affected by associated SNPs.

RESULTS

Evidence for linkage was observed at 10q26.3 (Zlr = 2.69; P = 0.0036; D10S1770) with borderline evidence for linkage at 10q22.3 (Zlr = 1.64; P = 0.05; D10S206). No evidence for linkage was seen at 3p25.3, 17q12, or 19q13.43. Peak association at 10q26.3 was in the intergenic region between TCERG1L and PPP2R2D (rs7922424; P = 9.47 × 10-6), immediately under the peak of linkage. Independent associations were observed at DOCK1 (rs9418832; P = 7.48 × 10-5) and ADAM12 (rs7902734; P = 8.04 × 10-4). RT-PCR analysis confirmed expression of all 4 genes in adenoid samples. ADAM12, DOCK1 and PPP2R2D, but not TCERG1L, were expressed in respiratory epithelial and macrophage cell lines. A significantly associated polymorphism (rs7087384) in strong LD with the top SNP (rs7922424; r2 = 0.97) alters a transcription factor binding site (CREB/CREBP) in the intergenic region between TCERG1L and PPP2R2D.

CONCLUSIONS

OM linkage was replicated at 10q26.3. Whilst multiple genes could contribute to this linkage, the weight of evidence supports PPP2R2D, a TGF-β/Activin/Nodal pathway modulator, as the more likely functional candidate lying immediately under the linkage peak for OM susceptibility at chromosome 10q26.3.

Panel 4: Recent advances in otitis media in molecular biology, biochemistry, genetics, and animal models

BACKGROUND

Otitis media (OM) is the most common childhood bacterial infection and also the leading cause of conductive hearing loss in children. Currently, there is an urgent need for developing novel therapeutic agents for treating OM based on full understanding of molecular pathogenesis in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM.

OBJECTIVE

To provide a state-of-the-art review concerning recent advances in OM in the areas of molecular biology, biochemistry, genetics, and animal model studies and to discuss the future directions of OM studies in these areas.

DATA SOURCES AND REVIEW METHODS

A structured search of the current literature (since June 2007). The authors searched PubMed for published literature in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM.

RESULTS

Over the past 4 years, significant progress has been made in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. These studies brought new insights into our understanding of the molecular and biochemical mechanisms underlying the molecular pathogenesis of OM and helped identify novel therapeutic targets for OM.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Our understanding of the molecular pathogenesis of OM has been significantly advanced, particularly in the areas of inflammation, innate immunity, mucus overproduction, mucosal hyperplasia, middle ear and inner ear interaction, genetics, genome sequencing, and animal model studies. Although these studies are still in their experimental stages, they help identify new potential therapeutic targets. Future preclinical and clinical studies will help to translate these exciting experimental research findings into clinical applications.

Panel 3: Recent advances in anatomy, pathology, and cell biology in relation to otitis media pathogenesis

BACKGROUND AND OBJECTIVES

The pathogenesis of otitis media (OM) involves a number of factors related to the anatomy, pathology, and cell biology of the middle ear, the mastoid, the Eustachian tube, and the nasopharynx. Although some issues of pathogenesis are fairly well established, others are only marginally indicated by current knowledge, and yet others remain undisclosed. The objective of this article is to provide a state-of-the-art review on recent scientific achievements in the pathogenesis of OM, as related to anatomy, pathology, and cell biology.

DATA SOURCES

PubMed, Ovid Medline, and Cochrane Library.

REVIEW METHODS

Articles published on the pathogenesis of OM and the anatomy, pathology, and cell biology of the middle ear, the mastoid, the Eustachian tube, and the nasopharynx between January 2007 and June 2011 were identified. Among almost 1900 abstracts, the authors selected 130 articles for full article review and inclusion in this report.

RESULTS

New knowledge on a number of issues emerged, including cell-specific expression and function of fluid transportation and innate immune system molecules, mucous cell metaplasia, mucin expression, bacterial adherence, and epithelial internalization, as well as the occurrence, composition, dynamics, and potential role of bacterial biofilm. In addition, the potential role of gastroesophageal reflux disease and cigarette smoke exposure has been explored further.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Over the past 4 years, considerable scientific progress has been made on the pathogenesis of OM, as related to issues of anatomy, pathology, and cell biology. Based on these new achievements and a sustained lack of essential knowledge, suggestions for future research are outlined.

Ciglitazone inhibits cigarette smoke solution-induced inflammatory responses in human middle ear epithelial cells

OBJECTIVE

Peroxisome proliferator activated receptor-γ (PPAR-γ), a member of the nuclear hormone receptor superfamily, plays an important role in the regulation of mucosal inflammation. The aim of this study was to investigate the anti-inflammatory effect of a PPAR-γ agonist, ciglitazone, on cigarette smoke solution (CSS)-induced inflammation in human middle ear epithelial cell lines (HMEECs).

DESIGN

HMEECs with or without ciglitazone pre-treatment were exposed to CSS in order to induce the inflammatory response. The suppressive effect of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and cyclooxygenase-2(COX-2), were evaluated using real-time polymerase chain reaction and Western blotting.

RESULTS

Stimulation with CSS at 40 μg/ml for 6 h resulted in a 4.1-fold increase in the expression of TNF-α mRNA in the HMEECs. CSS-induced up-regulation of TNF-α mRNA was decreased by more than 2.8-fold in cells pre-treated with ciglitazone. The up-regulation of COX-2 mRNA and increased COX-2 protein expression induced by CSS were also inhibited by more than 3.7-fold with ciglitazone pre-treatment.

CONCLUSIONS

These findings suggest that the inflammatory response induced by CSS could be inhibited by ciglitazone, a PPAR-γ agonist, in HMEECs. As such, PPAR-γ agonists may have therapeutic potential for the treatment of otitis media.

Effect of diesel exhaust particles on human middle ear epithelial cells

OBJECTIVE

In the present study, we investigate whether diesel exhaust particles (DEPs) cause cytotoxicity and induce inflammation or increase the expression of mucin in immortalized human middle ear epithelial cell lines (HMEECs). Several publications have shown an association between traffic-related air pollutants and otitis media. Additionally, DEP have been shown to cause inflammation and an allergic response in the airways.

METHODS

Cell viability following DEP treatment was investigated in HMEECs using the MTT assay. We measured the expression of the inflammatory cytokines TNF-α and COX-2 and the mucin genes MUC5AC and MUC5B using semiquantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting.

RESULTS

Cell viability tests showed that exposure to more than 80 μg/mL of DEP caused a decrease in cell viability. DEP exposure also increased the expression of MUC5AC, but did not induce the expression of MUC5B in HMEECs.

CONCLUSION

DEP decreased cell viability, induced an inflammatory response, and increased mucin gene expression in HMEECs. These findings support the hypothesis that environmental diesel exposure is a risk factor for otitis media.

Effects of Active and Passive Smoking on Ear Infections

Otitis media (OM) is one of the most frequent diseases in young children, causing to visit a physician, and also the most common indication for antibiotic prescription. The peak incidence and prevalence of OM is 6 to 18 months of age. In children, second-hand smoke (SHS) exposure is associated with upper and lower respiratory tract infections, such as acute otitis media (AOM), pneumonia, and bronchitis. Despite the overwhelming evidence of the role of SHS exposure on infant health, a very high proportion of children still continue to be exposed. This important relationship between all kinds of smoking and poor health may not be appreciated universally. With this article, we aim to review tobacco smoke exposure and OM connection. How this exposure may cause OM especially in young children? What can be done to prevent and to reduce the harmfull effects of tobacco smoking?