Expression of inflammatory mediators in the otitis media induced by Helicobacter pylori antigen in mice

The association between Helicobacter pylori and chronic otitis media with effusion

PURPOSE

Chronic otitis media with effusion (COME) is a common condition in children and a leading cause for hearing loss and ventilation tubes (VT) insertion. Among other risk factors, it is suggested that Helicobacter pylori (H. pylori) infection may have a role in the pathogenesis of COME. Previous studies have reached different results, and therefore, there is a need for further data on the relationship between H. pylori infection and COME development in children. Our objective is to investigate the presence of H. pylori in the middle-ear fluid (MEF) from children with COME.

METHODS

A Comparative cross-sectional study. Children ≤ 18 years were included. The study group included children diagnosed with COME and required VT insertion. The control group included children with acute otitis media (AOM) who required myringotomy in the emergency room. Middle-ear fluid samples were sent for both culture and bacterial identification using polymerase chain reaction (PCR) testing.

RESULTS

A total of 43 children were included. Eighteen with COME (median age 4 years, IQR 3-6), and 25 with AOM (median age 1 year, IQR 1-2). All samples were cultured for H. pylori. Twenty-two samples underwent H. pylori PCR testing of them, 12 samples from children with COME, and 10 from children with AOM. All cultures and PCR tests results were negative for H. pylori.

CONCLUSIONS

Our results suggest that H. pylori does not have a role in the pathogenesis of COME. Future larger studies are needed to investigate whether H. pylori has a role in the pathogenesis of COME.

Association between Helicobacter pylori and otitis media with effusion in children: A systematic review

BACKGROUND

Studies have shown that Helicobacter pylori (H. pylori) infection may be associated with the occurrence of otitis media with effusion (OME) in children.

OBJECTIVE

This is a systematic review of the relevant published literature to explore the relationship between H. pylori infection and OME in children.

METHOD

Articles published before October 30, 2019 in the PubMed, Web of Science, Ovid, the China National Knowledge Infrastructure (CNKI) database, and Wanfang databases were retrieved. Articles were screened based on prespecified inclusion and exclusion criteria. Quality assessment was applied to the included studies. Data in the included studies were extracted and classified for qualitative analysis.

RESULTS

Ten studies, which enrolled a total of 397 cases and 334 controls, were included; all were case-control studies of varying quality. We summarized and compared H. pylori infections in different specimens from pediatric patients with OME. Due to the apparent heterogeneity between the included studies, meta-analysis was not appropriate, hence we carried out only a qualitative analysis.

CONCLUSION

The detection rate of H. pylori in the middle ear, tonsil and gastric juice in children with OME was higher than that in children without OME. There is no clear and reliable conclusion as to whether there is a difference in the detection rate of H. pylori in adenoid specimens of children with or without OME. Eradication of H. pylori may improve symptoms of drug-resistant OME. Nevertheless, more studies of higher quality are needed to improve the conclusions.

Helicobacter pylori in Otorhinolaryngology: Cause or Bystander

The bacteria Helicobacter pylori (H. pylori) have been identified in the extragastric tissues in the head and neck. The origin and pathogenicity of these bacteria in the head and neck are not known. Gastric reflux and nasal or oral routes are the possible modes of spread. In many sinonasal, pharyngeal, laryngeal, and middle ear disorders, laryngopharyngeal reflux has been identified as a contributing or causative factor. One possible mode by which laryngopharyngeal reflux may contribute is by seeding of the extragastric mucosa with H. pylori. The clinical significance of the discovery of H. pylori in extragastric tissues in the head and neck is unclear. There is no evidence of a pathologic or active role of H. pylori in otorhinolaryngological disorders. The suggestion that the sinonasal cavities and pharynx may serve as a reservoir for H. pylori and that reinfection of the stomach occurs after eradication therapy awaits further studies for confirmation. No connection was observed between H. pylori found in the stomach and H. pylori found in the head and neck. Also, these bacteria, found in the head and neck tissues, may be accidental or innocent bystanders that do not affect the pathways of otolaryngological and gastroduodenal diseases. This review examines the evidence for a possible relationship of H. pylori with otorhinolaryngological diseases.

Otitis Media with Effusion and Helicobacter pylori

Previous studies reported the presence of Helicobacter pylori in middle ear fluid and raised a possible causal role of this bacterium in otitis media with effusion (OME). We investigated 48 children with OME (age, 7 months to 12 years) seen in New Orleans, Louisiana, and found no evidence of H pylori presence in any middle ear fluid specimen by amplification of the 16S rRNA gene. One child had H pylori detected in a stool specimen, in accordance with the low prevalence in our population. While H pylori may be significant in other countries, these findings do not support a role for H pylori in OME in our pediatric population in the United States.

An association between Helicobacter pylori and upper respiratory tract disease: Fact or fiction?

Helicobacter pylori (H. pylori) is a major cause of chronic gastritis and gastric ulcers and considerable evidence supports the notion that infection with this bacterium is also associated with gastric malignancy in addition to various other conditions including pulmonary, vascular and autoimmune disorders. Gastric juice infected with H. pylori might play an important role in upper respiratory tract infection. Although direct and/or indirect mechanisms might be involved in the association between H. pylori and upper respiratory tract diseases, the etiological role of H. pylori in upper respiratory tract disorders has not yet been fully elucidated. Although various studies over the past two decades have suggested a relationship between H. pylori and upper respiratory tract diseases, the findings are inconsistent. The present overview describes the outcomes of recent investigations into the impact of H. pylori on upper respiratory tract and adjacent lesions.

Expression of toll-like receptors in chronic otitis media and cholesteatoma

OBJECTIVE

Otitis media is one of the most common infectious diseases, especially in young children. Multiple factors affect the onset or development of otitis media. Human toll-like receptors recognize associated patterns and play a critical role in innate immune mechanisms. Toll-like receptors are considered to be important factors for clearance of infection and resolution of inflammation in otitis media. The purpose of this study was to evaluate the histological expression of toll-like receptor 2, which recognizes many kinds of pathogen-associated molecular patterns, and toll-like receptor 4, which recognizes lipopolysaccharide on Gram-negative bacteria, in tissue samples from patients with chronic otitis media and middle ear cholesteatoma.

METHODS

Human middle ear tissue samples from 12 patients with chronic otitis media (n=7) and acquired middle ear cholesteatoma (n=5) were examined. Normal control middle ear samples without any inflammation were also included (n=7). The expressions of toll-like receptors 2 and 4 in middle ear tissues were examined immunohistochemically.

RESULTS

Only one normal control middle ear sample showed weak expression of toll-like receptor 2, and toll-like receptor 4 was not observed in all control samples. On the other hand, both toll-like receptors 2 and 4 were markedly expressed in chronic otitis media and cholesteatoma. There was a significant difference between chronic otitis media and normal controls in the expressions of both toll-like receptors. Significant up-regulation of toll-like receptors 2 and 4 was observed in cholesteatoma as compared with control samples.

CONCLUSIONS

Toll-like receptors 2 and 4 were strongly expressed in chronic otitis media and middle ear cholesteatoma. These findings suggest that toll-like receptors may play a principal role in human chronic otitis media and cholesteatoma.

Panel 2

Objective

This report reviews the literature to identify the advances in our understanding of the middle ear (ME)–Eustachian tube (ET) system during the past 4 years and, on that basis, to determine whether the short-term goals elaborated in the last report were achieved and propose updated goals to guide future otitis media (OM) research.

Data Sources

Databases searched included PubMed, Web of Science (1945-present), Medline (1950 to present), Biosis Previews (1969-present), and the Zoological Record (1978 to present). The initial literature search covered the time interval from January 2007 to June 2011, with a supplementary search completed in February 2012.

Review Methods

The panel topic was subdivided; each contributor performed a literature search and provided a preliminary report. Those reports were consolidated and discussed when the panel met on June 9, 2011. At that meeting, the progress was evaluated and new short-term goals proposed.

Conclusions

Progress was made on 16 of the 19 short-term goals proposed in 2007. Significant advances were made in the characterization of ME gas exchange pathways, modeling ET function, and preliminary testing of treatments for ET dysfunction.

Implications for Practice

In the future, imaging technologies should be developed to noninvasively assess ME/ET structure and physiology with respect to their role in OM pathogenesis. The new data derived from form/function experiments should be integrated into the finite element models and used to develop specific hypotheses concerning OM pathogenesis and persistence. Finally, rigorous studies of treatments, medical or surgical, of ET dysfunction should be undertaken.

The Role of Helicobacter pylori in Upper Respiratory System Infections: Is it More Than Colonization?

Helicobacter pylori (HP) is recognized as a common chronic human bacterial infection and is the most common cause of gastritis. Recent studies suggest an increased HP prevalence in patients with various extra-digestive inflammatory diseases. Since many respiratory diseases are characterized by chronic inflammation as well as increased immune response, and HP may enter the nasopharyngeal cavity by gastroesophageal reflux, an association between respiratory disorders and HP infection has been suggested. Several studies discover HP in clinical samples from the patients with upper respiratory system infections. Even some of them revealed a relief after the treatment directed to HP eradication. However some studies do not support this theory and whether this association means a definite proof of a causal relationship between HP and respiratory diseases needs to be clarified. In this study, we aimed to review the reports about the role of HP in upper respiratory system infections.

HIF-VEGF pathways are critical for chronic otitis media in Junbo and Jeff mouse mutants

Otitis media with effusion (OME) is the commonest cause of hearing loss in children, yet the underlying genetic pathways and mechanisms involved are incompletely understood. Ventilation of the middle ear with tympanostomy tubes is the commonest surgical procedure in children and the best treatment for chronic OME, but the mechanism by which they work remains uncertain. As hypoxia is a common feature of inflamed microenvironments, moderation of hypoxia may be a significant contributory mechanism. We have investigated the occurrence of hypoxia and hypoxia-inducible factor (HIF) mediated responses in Junbo and Jeff mouse mutant models, which develop spontaneous chronic otitis media. We found that Jeff and Junbo mice labeled in vivo with pimonidazole showed cellular hypoxia in inflammatory cells in the bulla lumen, and in Junbo the middle ear mucosa was also hypoxic. The bulla fluid inflammatory cell numbers were greater and the upregulation of inflammatory gene networks were more pronounced in Junbo than Jeff. Hif-1α gene expression was elevated in bulla fluid inflammatory cells, and there was upregulation of its target genes including Vegfa in Junbo and Jeff. We therefore investigated the effects in Junbo of small-molecule inhibitors of VEGFR signaling (PTK787, SU-11248, and BAY 43-9006) and destabilizing HIF by inhibiting its chaperone HSP90 with 17-DMAG. We found that both classes of inhibitor significantly reduced hearing loss and the occurrence of bulla fluid and that VEGFR inhibitors moderated angiogenesis and lymphangiogenesis in the inflamed middle ear mucosa. The effectiveness of HSP90 and VEGFR signaling inhibitors in suppressing OM in the Junbo model implicates HIF–mediated VEGF as playing a pivotal role in OM pathogenesis. Our analysis of the Junbo and Jeff mutants highlights the role of hypoxia and HIF–mediated pathways, and we conclude that targeting molecules in HIF–VEGF signaling pathways has therapeutic potential in the treatment of chronic OM.

Otitis media with effusion (OME) is the commonest cause of hearing loss in children, and treatment using grommets remains the commonest surgical procedure in children. Chronic forms of OM are known from human population studies to have a significant genetic component, but little is known of the underlying genes or pathways involved. We have analyzed two chronic OM mouse models, the Junbo and Jeff mutants, and have found that both demonstrate hypoxia and hypoxia-inducible factor (HIF) mediated responses. There is upregulation of inflammatory pathways in the mutant middle ears and in Junbo elevation of cytokines that modulate Hif-1α. Hif-1α levels are raised in the middle ear as well as downstream targets of HIF such as Vegfa. We explored the effects of small-molecule inhibitors of HSP90 and VEGF receptor signaling in the Junbo mutant and found significant reductions in hearing loss, the occurrence of bulla fluid, and moderation of vascular changes in the inflamed middle ear mucosa with the VEGF receptor inhibitors. The study of the Junbo and Jeff mutants demonstrates the role of hypoxia and HIF mediated pathways in OM pathogenesis, and it indicates that targeting the HIF–VEGF pathway may represent a novel approach to therapeutic intervention in chronic OM.

Lipopolysaccharide induces proinflammatory cytokines and chemokines in experimental otitis media through the prostaglandin D2 receptor (DP)-dependent pathway

Otitis media is one of the most common and intractable ear diseases, and is the major cause of hearing loss, especially in children. Multiple factors affect the onset or development of otitis media. Prostaglandin D₂ is the major prostanoid involved in infection and allergy. However, the role of prostaglandin D₂ and prostaglandin D2 receptors on the pathogenesis of otitis media remains to be determined. Recent studies show that D prostanoid receptor (DP) and chemoattractant receptor-homologous molecule expressed on T helper type 2 (Th2) cells (CRTH2) are major prostaglandin D₂ receptors. In this study, homozygous DP single gene-deficient (DP⁻(/)⁻) mice, CRTH2 single gene-deficient (CRTH2⁻(/)⁻) mice and DP/CRTH2 double gene-deficient (DP⁻(/)⁻ CRTH2⁻(/)⁻) mice were used to investigate the role of prostaglandin D₂ and its receptors in otitis media. We demonstrate that prostaglandin D₂ is induced by lipopolysaccharide (LPS), a major component of Gram-negative bacteria, and that transtympanic injection of prostaglandin D₂ up-regulates macrophage inflammatory protein 2 (MIP-2), interleukin (IL)-1β and IL-6 in the middle ear. We also show that middle ear inflammatory reactions, including infiltration of inflammatory cells and expression of MIP-2, IL-1β and IL-6 induced by LPS, are reduced significantly in DP⁻(/)⁻ mice and DP⁻(/)⁻ CRTH2⁻(/)⁻ mice. CRTH2⁻(/)⁻ mice display inflammatory reactions similar to wild-type mice. These findings indicate that prostaglandin D₂ may play significant roles in LPS-induced experimental otitis media via DP.

Helicobacters and extragastric diseases

For two decades, Helicobacter pylori has been considered as the culprit in many extragastric manifestations. However, for several of these supposed associations the hypothesis of an etiological role has not yet been fully investigated. This may be due to a series of factors linked to the epidemiological features of the studies and to the diseases investigated. This review attempts to highlight the main reported associations of H. pylori with extragastric manifestations during the last year. The most convincing data arise in the field of idiopathic thrombocytopenic purpura (ITP) and sideropenic anemia. Long-term follow-up studies have shown that 50% of subjects with ITP maintain a hematological response after H. pylori eradication. There is also growing evidence of the role of H. pylori in other diseases, including ischemic heart disease even though results are not conclusive.