Is pre-operative audiometry a reliable predictor of ossicular chain condition?

OBJECTIVE: Investigation of ossicular chain (OC) status before surgery is important for preoperative patient consultation. This research aimed to investigate the relationship between pre-operative audiometric values and intra-operative OC condition in a relatively large population of chronic otitis media (COM) surgeries. METHODS: In this descriptive-analytic cross-sectional study, we evaluated 694 patients who underwent COM surgeries. We analyzed pre-operative audiometric data and intraoperative findings including ossicular anatomy, ossicular mobility, and the condition of middle ear mucosa. RESULTS: The optimal cut-off values of pre-operative speech reception threshold (SRT), mean air-conduction (AC), and mean air-bone gap (ABG) for predicting OC discontinuity were 37.5 dB, 37.2 dB, and 28.4 dB, respectively. For the prediction of OC fixation, the optimal cut-off points of SRT, mean AC, and mean ABG were 37.5 dB, 40.3 dB, and 32.8 dB, respectively. The computing of Cohen's d (95 % confidence interval) demonstrated the greater mean ABG in ears with OC discontinuity in comparison with ears with normal ossicles in all types of pathologies. There was a descending trend of Cohen's d from cholesteatoma to tympanosclerosis and then to granulation tissue and hypertrophic mucosa. There was a substantial relation between the type of pathology and OC status (P < 0.001). Ears with tympanosclerosis plaque had the most fixed OC among all types of pathologies (40 ears, 30.8 %), and ears with no pathology had the most normal OC (135 ears, 83.3 %). CONCLUSIONS: The results supported the view that pre-operative hearing is a key determining factor for the prediction of OC status.

Patulous eustachian tube after balloon eustachian tuboplasty in a post-radiation patient.

BACKGROUND: Balloon eustachian tuboplasty (BET) is a minimally invasive surgical treatment that is effective and safe for obstructive eustachian tube dysfunction. However, BET complications include excessive widening of the eustachian tube, causing a patulous eustachian tube (PET). Herein, we report a case of PET following BET in a patient who underwent radiation therapy and reviewed the literature on considerations for reducing complications after BET. CASE PRESENTATION: A 63-year-old woman complained of bilateral ear fullness after concurrent chemoradiation therapy for nasopharyngeal lymphoma. BET was performed on the left side because the left-sided serous otitis media persisted. A left-sided PET was performed two weeks after the BET, along with eustachian tube silicone plug insertion on the left side. The patient became asymptomatic immediately after the surgery, with no recurrence reported after a 12-month follow-up period. CONCLUSIONS: To our knowledge, there has been no report of PET following BET in a post-radiation patient, and it was successfully treated via ET silicone plug insertion.

Tuberculosis of the middle ear: A systematic review.

OBJECTIVE: Tuberculous otitis media (TOM) is a rare extrapulmonary manifestation of tuberculosis (TB) and remains challenging to diagnose due to non-specific symptoms. This systematic review identifies clinical characteristics, diagnostic evaluation, and outcomes in cases of TOM. METHODS: A comprehensive literature search utilizing the PubMed, CINAHL, Scopus, and Cochrane Library databases was conducted for relevant articles published between 2000 and 2021. Cases involving adult patients with TOM were included. Non-English studies, animal studies, and reviews were excluded. RESULTS: 41 case reports and 7 case series were included, comprising data from 67 patients. The mean age was 40 years (range, 19-87 years) and the majority were female (n = 46, 68.7 %). The mean symptom duration was 12.8 months (range, 0.25-120 months). Common symptoms included otorrhea (n = 60, 89.6 %), HL (n = 58, 86.6 %), otalgia (n = 19, 28.4 %), and FP (n = 18, 26.9 %). Otoscopy revealed tympanic membrane (TM) perforation in 45 patients (67.2 %). Most patients were diagnosed with tissue biopsy (n = 53, 79.1 %). Surgical interventions were performed in 48 patients (71.6 %) and 63 patients (94.0 %) were prescribed anti-TB chemotherapy. Long-term sequelae (e.g., HL, FP, and TM perforation) were noted in 39 patients (58.2 %) at a mean follow-up of 18.8 months (range, 1-120 months). CONCLUSION: TOM should be included in the differential diagnosis of chronic suppurative otitis media. Histopathological examination is a reliable diagnostic method. Early detection and management are recommended for optimizing outcomes. LEVEL OF EVIDENCE: 3b.

Macrophage Depletion in CCR2-/- Mice Delays Bacterial Clearance and Enhances Neutrophil Infiltration in an Acute Otitis Media Model.

BACKGROUND: Otitis media (OM) is a common and potentially serious disease of childhood. Although OM is multifactorial on origin, bacterial infection is a unifying component. Many studies have established a critical role for innate immunity in bacterial clearance and OM resolution. A key component of innate immunity is the recruitment of immune and inflammatory cells, including macrophages. METHODS: To explore the role of macrophages in OM, we evaluated the expression of genes related to macrophage function during a complete episode of acute OM in the mouse caused by middle ear (ME) inoculation with Haemophilus influenzae. We also combined CCR2 deficiency with chlodronate liposome toxicity to deplete macrophages during OM. RESULTS: Macrophage genes were robustly regulated during OM. Moreover, macrophage depletion enhanced and prolonged the infiltration of neutrophils into the infected ME and increased the persistence of bacterial infection. CONCLUSIONS: The results illustrate the critical role played by macrophages in OM resolution.

Mapping the distribution of stem/progenitor cells across the mouse middle ear during homeostasis and inflammation.

The middle ear epithelium is derived from neural crest and endoderm, which line distinct regions of the middle ear cavity. Here, we investigate the distribution of putative stem cell markers in the middle ear, combined with an analysis of the location of label-retaining cells (LRCs) to create a map of the middle ear mucosa. We show that proliferating cells and LRCs were associated with specific regions of the ear epithelium, concentrated in the hypotympanum at the base of the auditory bulla and around the ear drum. Sox2 was widely expressed in the endodermally derived ciliated pseudostratified epithelium of the hypotympanum. This part of the middle ear showed high levels of Wnt activity, as indicated by the expression of Axin2, a readout of Wnt signalling. Keratin 5 showed a more restricted expression within the basal cells of this region, with very little overlap between the Sox2- and keratin 5-positive epithelium, indicating that these genes mark distinct populations. Little expression of Sox2 or keratin 5 was observed in the neural crest-derived middle ear epithelium that lined the promontory, except in cases of otitis media when this epithelium underwent hyperplasia. This study lays the foundation for furthering our understanding of homeostasis and repair in the middle ear.

IL13 May Play an Important Role in Developing Eosinophilic Chronic Rhinosinusitis and Eosinophilic Otitis Media with Severe Asthma.

A woman in her 50s was a super responder to benralizumab administered for the treatment of severe bronchial asthma (BA) with eosinophilic chronic rhinosinusitis with nasal polyp (ECRS) and eosinophilic otitis media (EOM). She exhibited the gradual exacerbation of ECRS/EOM despite good control of BA approximately 1 year after benralizumab initiation. Therefore, the treatment was switched to dupilumab, and the condition of the paranasal sinuses and middle ear greatly improved with the best control of her asthma. The patient reported that her physical condition was the best of her life. However, she developed a pulmonary opacity on chest computed tomography after 6 months. Histological examination of the lung parenchyma and cell differentiation of the bronchoalveolar lavage fluid indicated atypical chronic eosinophilic pneumonia, and treatment was switched to mepolizumab. Similarly to the period of benralizumab treatment, exacerbation of ECRS/EOM reduced her quality of life approximately 10 months after the administration of mepolizumab. Dupilumab was again introduced as a replacement for mepolizumab. The clinical course and consideration of the interaction between inflammatory cells led us to speculate that interleukin-13 could play a key role in the development of ECRS/EOM with severe BA.

Identifying distinct trajectories of acute otitis media in children: A prospective cohort study.

OBJECTIVES: To identify possibly distinct acute otitis media (AOM) trajectories in childhood and identify determinants associated with specific AOM trajectories. To explore which child will become prone to recurrent AOM episodes and which will not. DESIGN: Population-based prospective cohort study among 7863 children from birth until 10 years and their mothers. METHODS: This study was embedded in the Generation R Study: a population-based prospective cohort study. Data on AOM and determinants were collected by repeated parental questionnaires. Distinct AOM trajectories within the population were identified with latent-class analyses. Next, using multivariate analysis we checked whether specific determinants were associated with specific trajectories. RESULTS: Three distinct trajectories were identified; that is, non-otitis prone, early AOM-that is children who suffered AOM episodes until 3 years of age but not beyond, and persistent AOM-that is children who remained otitis-prone. Male gender (OR: 1.26, CI: 1.11-1.43) and day-care attendance (OR: 1.31, CI: 1.06-1.60) were associated with increased odds of early AOM. Breastfeeding was beneficial for children in both the early-AOM and persistent-AOM trajectories (OR: 0.78 and 0.77, respectively). Birth in the summer or autumn as compared with birth in the spring decreased odds of AOM only in the persistent-AOM trajectory. Half of all AOM-prone children recovered after the age of 3 years. CONCLUSION: Specific determinants are associated with different AOM trajectories. Future research is needed to better predict which child will remain otitis-prone and which recovers after the age of 3 years to better tailor treatment towards the needs of the individual child.

Cellular content plays a crucial role in Non-typeable Haemophilus influenzae infection of preinflamed Junbo mouse middle ear.

Non-typeable Haemophilus influenzae (NTHi) is a major pathogen causing acute otitis media (AOM). The relationship between the cellular content of the middle ear fluid (MEF) during AOM and infection of NTHi is poorly understood. Using the Junbo mouse, a characterised NTHi infection model, we analysed the cellular content of MEF and correlated the data with NTHi titres. The MEF of the Junbo mouse was heterogeneous between ears and was graded from 1 to 5; 1 being highly serous/clear and 5 being heavily viscous/opaque. At seven-day post-intranasal inoculation, NTHi was not found in grade-1 or 2 fluids, and the proportion of MEF that supported NTHi increased with the grade. Analyses by flow cytometry indicated that the cellular content was highest in grade-4 and 5 fluids, with a greater proportion of necrotic cells and a low-live cell count. NTHi infection of the middle ear increased the cell count and led to infiltration of immune cells and changes in the cytokine and chemokine levels. Following NTHi inoculation, high-grade infected MEFs had greater neutrophil infiltration whereas monocyte infiltration was significantly higher in serous noninfected low-grade fluids. These data underline a role for immune cells, specifically monocytes and neutrophils, and cell necrosis in NTHi infection of the Junbo mouse middle ear.

Otitis Media and Inborn Errors of Immunity.

PURPOSE OF REVIEW: The aim of this review is as follows: (1) to present the role of otitis as a warning sign for inborn errors of immunity (IEI), (2) to establish which patients presenting otitis should be investigated for IEI, (3) to review data about main IEI associated with otitis-prone patients. RECENT FINDINGS: Otitis media is a very common infection in general population. The concept of otitis-prone children established a certain frequency of the infections in order to look for conditions leading to them. The confirmation of middle ear impairment by specialists has demonstrated better confiability. The hallmarks for immunologic evaluation are the presence of complications as mastoiditis and membrane perforation, failure to thrive, and additional respiratory symptoms. Humoral immunodeficiencies have been more frequently described in association with otitis-prone patients, for example, hypogammaglobulinemia, MBL deficiency, and IEI associated with major syndromes. Most of the patients with confirmed IEI present otitis as one of the recurrent infections. It is suggested the investigation of immune defects in patients with otitis, and the following warning signs are suggested: Otitis evolving with mastoiditis, abscesses, or systemic infections; no response to appropriate antibiotic therapy; otitis media associated with other infections; recurrent otitis leading to failure to thrive and general developmental delay; and family history of primary immunodeficiency and/or consanguinity.

Proteomic Study Identifies Glycolytic and Inflammation Pathways Involved in Recurrent Otitis Media.

Recurrent acute otitis media (RAOM) in children is clinically defined as the occurrence of at least three episodes of acute otitis media over a course of 6 months. A further common pathological condition of interest in the context of pediatric otolaryngology is adenotonsillar hypertrophy (ATH), a common cause of obstructive sleep apnea syndrome. Aimed at unraveling the differential modulation of proteins in the two pathologies and at understanding the possible pathways involved in their onset, we analyzed the proteomic profile of the adenoids from 14 RAOM and ATH patients by using two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS). The 2-DE coupled with MS allowed us to identify 23 spots with significant (p-value < 0.05) changes in protein amount, recognizing proteins involved in neutrophil degranulation and glycolysis pathways.

Impact of the demographic and aetiological factors and intraoperative findings on postoperative outcomes in chronic otitis media surgery

Background/aim: Surgical success is related with many factors belonging to both the patient and the disease. This study aims to analyse the preoperative and intraoperative characteristics, the postoperative results, and the factors affecting the surgical success in different types of chronic otitis media (COM). Materials and methods: A total of 1510 ears of 1398 patients who underwent COM surgery were included in the study. Postoperative results were obtained from 376 ears of 356 patients who had been followed after surgery. The demographic characteristics of the patients, such as age and sex, operative findings, preoperative audiological examination results, and final audiometric and otoscopic examination findings, were retrospectively obtained from the archives of the department. Results: The most frequent diagnosis was simple COM (39.9%), and the most frequently performed surgery was tympanoplasty without mastoidectomy (46.6%). The overall hearing success rate was found to be 75.8%. Postoperative hearing success was significantly associated with the chronic otitis subgroup, ossicular pathologies, and the condition of the middle ear mucosa. Postoperative graft take rate was found to be 78.6%. Graft success was statistically significantly higher in patients with normal middle ear mucosa. Performing mastoidectomy, the presence of patency in aditus ad antrum, and being a paediatric case had no impact on graft success. Conclusion: Factors affecting the success of COM surgery include age, chronic otitis subgroup, location and size of perforation, the condition of the middle ear mucosa, and the level of the ossicular disease. These factors should be known and an appropriate treatment plan should be prepared.

Titanium ossicular chain reconstruction in single stage canal wall down tympanoplasty for chronic otitis media with mucosa defect.

PURPOSE: To evaluate surgical outcomes for chronic otitis media with mucosa defect underwent titanium ossicular chain reconstruction (OCR) in single stage canal wall down tympanoplasty (CWD). METHODS: A clinical retrospective study was performed on 83 cases of the chronic otitis media with mucosa defect and 123 ears with mucosa integrity according to intraoperative findings that underwent synchronous titanium OCR in single stage CWD form January 2012 to January 2018. Pre- and postoperative air conduction threshold (AC), air-bone gap (ABG) and ABG closure at 0.5, 1, 2, and 4 kHz were investigated. RESULTS: The overall mean AC threshold of 53.4 ±â€¯16.5 dB was lowered to 41.2 ±â€¯15.9 dB postoperatively (p < 0.01). The mean pre- and postoperative ABG of all patients were 27.9 ±â€¯9.9 dB and 17.2 ±â€¯9.3 dB (p < 0.01), respectively, with a mean ABG closure of 10.7 ±â€¯8.4 dB. The total rate of success, postoperative ABG ≤ 20 dB was achieved in 71.4%. In the mucosa defect group underwent TORP, the mean pre- and postoperative ABG were 28.1 ±â€¯9.8 dB and 20.1 ±â€¯9.0 dB (p < 0.01), respectively, with the ABG closure was 8.0 ±â€¯7.9 dB. In the mucosa defect group underwent PORP, the mean pre- and postoperative ABG were 27.9 ±â€¯10.1 dB and 16.5 ±â€¯9.1 dB (p < 0.01), respectively, with the ABG closure was 11.4 ±â€¯8.6 dB. Furthermore, in the mucosa defect group, there was significant difference in success rate of achieved postoperative ABG ≤ 20 dB between the TORP (48.9%) and PORP (77.5%) (p < 0.05). CONCLUSION: It is revealed PORP in single stage CWD tympanoplasty for the patients suffered from chronic otitis media with mucosa defect is favored.

Ossicular chain erosion in chronic otitis media patients with cholesteatoma or granulation tissue or without those: analysis of 915 cases.

PURPOSE: The aim of this study was to evaluate the ossicular chain erosions (OCE) in chronic otitis media patients with cholesteatoma (COM-C) or without cholesteatoma (COM). MATERIALS AND METHODS: The OCE and preoperative hearing levels of a total of 915 patients were evaluated retrospectively. Patients were divided into three groups. Of the 915 patients, 615 (67.2%) had COM, 234 (25.6%) had COM-C, and 66 (7.2%) had chronic otitis media with granulation tissue (COM-G). RESULTS: OCE was found in 291 (31.8%) of 915 patients. OCE was found in 192 (82%) of 234 patients with COM-C, 21 (31.8%) of 66 patients with COM-G, and 78 (12.7%) of 615 patients with COM. CONCLUSION: The most commonly seen OCE was incus erosion, followed by stapes and malleus erosions. The results of this study show that there are more OCE in the COM-C group than in the COM-G and COM groups. To our knowledge, this study has the widest patient population in the literature focused on the OCE relation with COM, COM-C, and COM-G and its effect on the preoperative hearing level.

Pneumococcal Phenotype and Interaction with Nontypeable Haemophilus influenzae as Determinants of Otitis Media Progression.

All-cause otitis media (OM) incidence has declined in numerous settings following introduction of pneumococcal conjugate vaccines (PCVs) despite increases in carriage of nonvaccine pneumococcal serotypes escaping immune pressure. To understand the basis for the declining incidence, we assessed the intrinsic capacity of pneumococcal serotypes to cause OM independently and in polymicrobial infections involving nontypeable Haemophilus influenzae (NTHi) using samples obtained from middle ear fluid and nasopharyngeal cultures before PCV7/13 rollout. Data included samples from OM episodes (11,811) submitted for cultures during a 10-year prospective study in southern Israel and nasopharyngeal samples (1,588) from unvaccinated asymptomatic children in the same population. We compared data representing pneumococcal serotype diversity across carriage and disease isolates with and without NTHi coisolation. We also measured associations between the pneumococcal phenotype and the rate of progression from colonization to OM in the presence and absence of NTHi. Whereas pneumococcal serotype diversity was lower in single-species OM than in single-species colonization, levels of serotype diversity did not differ significantly between colonization and OM in mixed-species episodes. Serotypes differed roughly 100-fold in progression rates, and those differences were attenuated in polymicrobial episodes. Vaccine serotype pneumococci had higher rates of progression than nonvaccine serotypes. While serotype invasiveness was a weak predictor of the OM progression rate, efficient capsular metabolic properties-traditionally thought to serve as an advantage in colonization-predicted an enhanced rate of progression to complex OM. The lower capacity of nonvaccine serotypes to cause OM may partially account for reductions in all-cause OM incidence despite serotype replacement in carriage following rollout of PCVs.

An experimental murine model of otitis and dermatitis caused by Malassezia pachydermatis.

We report a malasseziosis model in immunocompromised Swiss mice. For this model, the mice were immunosuppressed with a combination of cyclophosphamide at 150 mg/kg and hydrocortisone acetate at 250 mg/kg. Two groups were formed according to the site of inoculation. Dermatitis group received an intradermal injection of 5 × 106 cell/mouse at a shaved dorsal region, while the otitis group received the same inoculum in the middle ear. Five animals/group were euthanised at different times, and the skin and ear were histopathologically analysed. During the first euthanasia, which occurred after inoculation, microscopic examination showed that all mice presented budding yeast-like in a tissue sample. The presence of yeasts decreased over time being undetected on the 17th day (dermatitis group) and the 21st day (otitis group) after inoculation. This is the first murine model for malasseziosis that can be useful for evaluating new treatment approaches.

Computed tomographic findings in 205 dogs with clinical signs compatible with middle ear disease: a retrospective study.

BACKGROUND: Computed tomography (CT) is considered to be the reference method to evaluate middle ear structures. OBJECTIVES: To evaluate the presence and severity of CT changes in the middle ear and establish if any specific clinical presentations are associated with otitis media. ANIMALS: Medical records of animals referred for CT with history and clinical signs consistent with middle ear disease. METHODS: Retrospective evaluation of CT examinations of tympanic bullae performed over a six year period. Medical records were reviewed for signalment, clinical signs and cytological evaluation of the external ear canal. Dogs were divided into three clinical groups: chronic otitis externa (Group 1), peripheral vestibular disorder (Group 2) and other clinical presentations (Group 3). RESULTS: Group 1 - Of 214 ears, 87 (40.7%) had CT abnormalities: 38 of 87 (17.7%) had material-filled bullae, 42 of 87 (19.6%) had thickened bullae walls and seven of 87 (3.2%) had lysis of the bulla. Abnormalities were significantly more frequent in dogs with suppurative otitis than in erythemato-ceruminous otitis (57% and 23%, respectively; P = 0.003). Proliferative otitis, particularly in French bulldogs, was associated with severe otitis media. Group 2 - Of the 106 ears, 91 (85.8%) had normal tympanic bullae. Group 3 - Of the 26 ears from deaf dogs, 17 had filled bullae; all nine affected dogs were Cavalier King Charles spaniels. All dogs with Claude Bernard Horner syndrome or head tilt had normal tympanic bullae. CLINICAL SIGNIFICANCE: CT is useful for canine chronic otitis externa, particularly in suppurative or proliferative otitis, even in the absence of associated neurological signs.

Haemophilus parainfluenzae Strain ATCC 33392 Forms Biofilms In Vitro and during Experimental Otitis Media Infections.

Haemophilus parainfluenzae is a nutritionally fastidious, Gram-negative bacterium with an oropharyngeal/nasopharyngeal carriage niche that is associated with a range of opportunistic infections, including infectious endocarditis and otitis media (OM). These infections are often chronic/recurrent in nature and typically involve bacterial persistence within biofilm communities that are highly resistant to host clearance. This study addresses the primary hypothesis that H. parainfluenzae forms biofilm communities that are important determinants of persistence in vivo The results from in vitro biofilm studies confirmed that H. parainfluenzae formed biofilm communities within which the polymeric matrix was mainly composed of extracellular DNA and proteins. Using a chinchilla OM infection model, we demonstrated that H. parainfluenzae formed surface-associated biofilm communities containing bacterial and host components that included neutrophil extracellular trap (NET) structures and that the bacteria mainly persisted in these biofilm communities. We also used this model to examine the possible interaction between H. parainfluenzae and its close relative Haemophilus influenzae, which is also commonly carried within the same host environments and can cause OM. The results showed that coinfection with H. influenzae promoted clearance of H. parainfluenzae from biofilm communities during OM infection. The underlying mechanisms for bacterial persistence and biofilm formation by H. parainfluenzae and knowledge about the survival defects of H. parainfluenzae during coinfection with H. influenzae are topics for future work.

Otitis Media and Nasopharyngeal Colonization in ccl3-/- Mice.

We previously found CC chemokine ligand 3 (CCL3) to be a potent effector of inflammation during otitis media (OM): exogenous CCL3 rescues the OM phenotype of tumor necrosis factor-deficient mice and the function of macrophages deficient in several innate immune molecules. To further delineate the role of CCL3 in OM, we evaluated middle ear (ME) responses of ccl3-/-mice to nontypeable Haemophilus influenzae (NTHi). CCL chemokine gene expression was evaluated in wild-type (WT) mice during the complete course of acute OM. OM was induced in ccl3-/- and WT mice, and infection and inflammation were monitored for 21 days. Phagocytosis and killing of NTHi by macrophages were evaluated by an in vitro assay. The nasopharyngeal bacterial load was assessed in naive animals of both strains. Many CCL genes showed increased expression levels during acute OM, with CCL3 being the most upregulated, at levels 600-fold higher than the baseline. ccl3-/- deletion compromised ME bacterial clearance and prolonged mucosal hyperplasia. ME recruitment of leukocytes was delayed but persisted far longer than in WT mice. These events were linked to a decrease in the macrophage capacity for NTHi phagocytosis and increased nasopharyngeal bacterial loads in ccl3-/- mice. The generalized impairment in inflammatory cell recruitment was associated with compensatory changes in the expression profiles of CCL2, CCL7, and CCL12. CCL3 plays a significant role in the clearance of infection and resolution of inflammation and contributes to mucosal host defense of the nasopharyngeal niche, a reservoir for ME and upper respiratory infections. Therapies based on CCL3 could prove useful in treating or preventing persistent disease.

Interleukin-17A Aggravates Middle Ear Injury Induced by Streptococcus pneumoniae through the p38 Mitogen-Activated Protein Kinase Signaling Pathway.

Acute otitis media (AOM) is one of the most common bacterial infectious diseases in children aged 2 to 7 years worldwide. We previously demonstrated that interleukin-17A (IL-17A) promotes an acute inflammatory response characterized by the influx of neutrophils into the middle ear cavity during Streptococcus pneumoniae-induced AOM. In general, the inflammatory response is viewed as an effector that frequently causes local tissue damage. However, little is known about the pathogenic effects of IL-17A in AOM. Here, we investigated the pathogenic effects of IL-17A by using wild-type (WT) and IL-17A knockout (KO) mouse models. The results showed that the pathogenic effects of AOM, including weight loss, histopathological changes, and proinflammatory cytokine production, were more severe in WT mice than in IL-17A KO mice, suggesting that IL-17A aggravates tissue damage in AOM. Furthermore, these pathogenic effects were found to be dependent on p38 mitogen-activated protein kinase (MAPK) and could be reversed in the presence of a p38 MAPK-specific inhibitor. It was also demonstrated that IL-17A promoted the production of neutrophil myeloperoxidase (MPO) through the p38 MAPK signaling pathway, which was responsible for the middle ear tissue injury. These data support the conclusion that IL-17A contributes to middle ear injury through the p38 MAPK signaling pathway.

Inner ear disturbances related to middle ear inflammation.

The inner and middle ear are connected mainly through round and oval windows, and inflammation in the middle ear cavity can spread into the inner ear, which might induce a disturbance. In cases with intractable otitis media, attention should also be paid to symptoms related to the inner ear. In this paper, middle ear inflammation and related inner ear disturbances are reviewed with a focus on representative middle ear diseases (such as acute otitis media, chronic otitis media, otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitis, eosinophilic otitis media, cholesteatoma with labyrinthine fistula, and reflux-related otitis media). Their clinical concerns are then discussed with reference to experimental studies. In these diseases, early diagnosis and adequate treatment are required to manage not only middle ear but also inner ear conditions.