Current understanding of the pathogenesis of autoimmune inner ear disease: a review

Human blood-labyrinth barrier model to study the effects of cytokines and inflammation

Hearing loss is one of the 10 leading causes of disability worldwide. No drug therapies are currently available to protect or restore hearing. Inner ear auditory hair cells and the blood-labyrinth barrier (BLB) are critical for normal hearing, and the BLB between the systemic circulation and stria vascularis is crucial for maintaining cochlear and vestibular homeostasis. BLB defects are associated with inner ear diseases that lead to hearing loss, including vascular malformations, inflammation, and Meniere's disease (MD). Antibodies against proteins in the inner ear and cytokines in the cochlea, including IL-1α, TNF-α, and NF-kβ, are detected in the blood of more than half of MD patients. There is also emerging evidence of inner ear inflammation in some diseases, including MD, progressive sensorineural hearing loss, otosclerosis, and sudden deafness. Here, we examined the effects of TNF-α, IL6, and LPS on human stria vascularis-derived primary endothelial cells cultured together with pericytes in a Transwell system. By measuring trans-endothelial electrical resistance, we found that TNF-α causes the most significant disruption of the endothelial barrier. IL6 had a moderate influence on the barrier, whereas LPS had a minimal impact on barrier integrity. The prominent effect of TNF-α on the barrier was confirmed in the expression of the major junctional genes responsible for forming the tight endothelial monolayer, the decreased expression of ZO1 and OCL. We further tested permeability using 2 μg of daptomycin (1,619 Da), which does not pass the BLB under normal conditions, by measuring its passage through the barrier by HPLC. Treatment with TNF-α resulted in higher permeability in treated samples compared to controls. LPS-treated cells behaved similarly to the untreated cells and did not show differences in permeability compared to control. The endothelial damage caused by TNF-α was confirmed by decreased expression of an essential endothelial proteoglycan, syndecan1. These results allowed us to create an inflammatory environment model that increased BLB permeability in culture and mimicked an inflammatory state within the stria vascularis.

Human blood-labyrinth barrier on a chip: a unique in vitro tool for investigation of BLB properties

Hearing loss is one of the leading causes of disability worldwide, usually as a result of hair cell damage in the inner ear due to aging, acoustic trauma, or exposure to antibiotics or chemotherapy. No drug therapies can protect or restore hearing and current in vitro and animal models used in drug discovery have a very low success rate, mostly due to major differences in anatomy and accessibility of the inner ear environment between species. The blood-labyrinth barrier (BLB) in the stria vascularis is a highly specialized capillary network that controls exchanges between the blood and interstitial space in the cochlea. The BLB is critical for normal hearing, functioning as a physical, transport, and metabolic barrier. To address its complexity and accessibility, we created the first micro-engineered human model of BLB on a chip using autogenous progenitor cells from adult temporal bones. We successfully isolated the BLB from post-mortem human tissue and established an endothelial cell and pericyte culture system on a BLB chip. Using biocompatible materials, we fabricated sustainable two chamber chips. We validated the size-dependent permeability limits of our BLB model by measuring the permeability to daptomycin (molecular weight 1.6 kDa) and midazolam (molecular weight 325.78 Da). Daptomycin did not pass through the BLB layer, whereas midazolam readily passed through the BLB in our system. Thus, our BLB-chip mimicked the integrity and permeability of human stria vascularis capillaries. This represents a major step towards establishing a reliable model for the development of hearing loss treatments.

Relapsing autoimmune inner ear disease with significant response to methotrexate and azathioprine combination therapy: A case report and mini literature review

RATIONALE

Autoimmune inner ear disease typically presents with bilateral hearing loss that progresses over weeks or months though its mechanisms are unknown. Corticosteroids are the first-line treatment, but their responses are variable and relapses are frequent. Thus, many experts have sought to replace corticosteroids with immunosuppressive agents.

PATIENT CONCERNS

A 35-year-old woman experienced a progressive hearing impairment, initially on the left side and later becoming bilateral. Her response to corticosteroid monotherapy was temporary, and there have been two relapse episodes over several months.

DIAGNOSES

Autoimmune inner ear disease was considered due to evidence of autoimmunity combined with a clinical course of bilateral and recurrent sensorineural hearing loss and a partial response to corticosteroid therapy.

INTERVENTIONS

The patient received a 3-day mini-pulse of methylprednisolone at 250 mg/d, followed by 12 mg/d maintenance, and concurrently began an azathioprine regimen gradually increasing to 100 mg/day as a corticosteroid-sparing agent.

OUTCOMES

Three weeks after immunosuppressive therapy, hearing and pure-tone audiometry improved, and after 7 weeks, methylprednisolone was tapered to 8 mg/d. The dosage was further reduced by adding methotrexate at 7.5 mg/week, resulting in a reduction to 4 mg/d as maintenance therapy after 4 weeks.

LESSONS

For patients who are unresponsive to corticosteroids or experience difficulty tolerating them, a combination therapy of methotrexate and azathioprine is recommended as a viable alternative as this regimen is well-tolerated and yields positive outcomes.

Sex differences in autoimmune inner ear disease treatment and audiological outcomes

OBJECTIVE

The primary objective of this study was to assess possible sex-related differences in AIED treatment. The secondary aim was to assess the long-term outcomes of treatment using pre- and post-treatment audiometry and speech discrimination scores.

METHODS

Adult patients with a diagnosis of AIED who were treated for their condition at the senior author's (RTS) practice from 2010 to 2022 were included in this study. Patients were grouped as males or females for further analysis and comparison. Data included past medical history, medication use, surgical history and social history. Air-conduction thresholds (500 to 8000 Hz) were collected and averaged into discrete variables for pre- and post-treatment. The change (∆) and percent change (%∆) of these variables following therapy were analyzed. Speech discrimination score (SDS) testing results were taken at the same time points as pure tone averages, and patients were sub-stratified based on evidence of improvement in SDS and compared accordingly.

RESULTS

One hundred eighty-four patients (78 male/106 female) were included in this study. The mean age of the male participants was 57.18 ± 15.92 years, and the mean age of the female participants was 53.49 ± 16.04 years (p = 0.220). Comorbid autoimmune disease (AD) was more prevalent in females than in males (38.7 % vs. 16.7 %, p = 0.001). Of the patients treated with oral steroids, females received significantly more courses than males (2.554 ± 2.078 vs. 1.946 ± 1.301, p = 0.020). However, the average duration of oral steroids used per trial did not differ significantly between males and females (21.02 ± 18.05 vs. 20.62 ± 7.49, p = 0.135). Audiological results demonstrated that the change (∆) in pure tone average (PTA) at 0.5, 1, 2, and 3 kHz (-4.21 ± 6.394 vs. -3.91 ± 6.105) and high-frequency pure tone average (HFPTA) at 4, 6, and 8 kHz (-4.55 ± 6.544 vs. -2.19 ± 6.842) was not significantly different between the sexes following treatment (p = 0.376 and p = 0.101, respectively). Similarly, the percentage change (%∆) in PTA (-13.17 % vs. -15.01 %) and HFPTA (-8.50 % vs. -6.76 %) also did not differ significantly between males and females (p = 0.900 and p = 0.367, respectively). One hundred-five (57.1 %) patients qualified for the SDS improvement subgroup for analysis, with 50 (47.6 %) being male and 55 (51.9 %) being female (p = 0.159). The change (∆) in SDS (15.12 ± 21.159 vs. 10.62 ± 19.206) and the percentage change (%∆) in SDS (16.71 % vs. 12.40 %) also showed no significant difference between male and female patients (p = 0.312 and p = 0.313, respectively).

CONCLUSION

AIED is not a uniform condition regarding clinical presentation, audiological findings or progression, nor is its treatment straightforward. The utilization and duration of cytotoxic medications, as well as PTA and SDS findings, did not differ between the sexes. However, significantly more courses of oral steroids were prescribed to females than males. Sex as a biological variable and its implications in the pathogenesis and treatment of AIED warrant further study.

The role of the stria vascularis in neglected otologic disease

The stria vascularis (SV) has been shown to play a critical role in the pathogenesis of many diseases associated with sensorineural hearing loss (SNHL), including age-related hearing loss (ARHL), noise-induced hearing loss (NIHL), hereditary hearing loss (HHL), and drug-induced hearing loss (DIHL), among others. There are a number of other disorders of hearing loss that may be relatively neglected due to being underrecognized, poorly understood, lacking robust diagnostic criteria or effective treatments. A few examples of these diseases include autoimmune inner ear disease (AIED) and/or autoinflammatory inner ear disease (AID), Meniere's disease (MD), sudden sensorineural hearing loss (SSNHL), and cytomegalovirus (CMV)-related hearing loss (CRHL). Although these diseases may often differ in etiology, there have been recent studies that support the involvement of the SV in the pathogenesis of many of these disorders. We strive to highlight a few prominent examples of these frequently neglected otologic diseases and illustrate the relevance of understanding SV composition, structure and function with regards to these disease processes. In this study, we review the physiology of the SV, lay out the importance of these neglected otologic diseases, highlight the current literature regarding the role of the SV in these disorders, and discuss the current strategies, both approved and investigational, for management of these disorders.

[Autoimmune hearing loss and a chance of its development in children: literature review and own observations]

Autoimmune sensorineural hearing loss (AiSNHL) is an uncommon auditory disorder characterized by rapidly progressive bilateral hearing loss and a positive clinical response to treatment with corticosteroids and cytostatics. The prevalence of the disease in the adult population is less than 1% among all cases of subacute and permanent sensorineural hearing loss (precise data are unknown), it is even rarer in children. AiSNHL can be primary (isolated, organ-specific) or secondary (manifestation of another systemic autoimmune disease). The pathogenesis of AiSNHL is based on the proliferation of autoaggressive T cells and the pathological production of autoantibodies to the protein structures of the inner ear, which leads to damage to various parts of the cochlea (possibly also to the retrocochlear parts of the auditory system), less frequently to the vestibular labyrinth. Pathologically, the disease is most often represented by cochlear vasculitis with degeneration of the vascular stria, damage to hair cells and spiral ganglion cells, and endolymphatic hydrops. In 50% of cases, the result of autoimmune inflammation may be fibrosis and/or ossification of the cochlea. The most characteristic symptoms of AiSNHL at any age are episodes of sudden progression of hearing loss, fluctuations of hearing thresholds, and bilateral, often asymmetric impairments. The article presents contemporary ideas of the clinical and audiological manifestations of AiSNHL, the possibilities of diagnosing and treating the disease, and highlights the current approaches to (re)habilitation. Along with literature data, two own clinical cases of an extremely rare pediatric AiSNHL are given.

Disease-Modifying Antirheumatic Drugs in the Treatment of Autoimmune Inner Ear Disease: A Systematic Review and Meta-Analysis of Auditory and Vestibular Outcomes

OBJECTIVE

To answer the following question: In patients with primary autoimmune inner ear disease (AIED), (population) what impact do disease-modifying antirheumatic agents (DMARDs) (intervention) when compared with no treatment or corticosteroids (comparison) have on auditory and vestibular outcomes (outcome)?

STUDY DESIGN

Systematic review and meta-analysis.

DATA SOURCES

According to PRISMA guidelines, PubMed, Scopus, CINAHL, and Cochrane Library databases were searched from inception to March 10, 2022.

STUDY SELECTION

Studies of patients receiving DMARDs for the treatment of AIED were selected for review. Case reports, phase I/II trials, studies of patients with secondary AIED, and studies of AIED patients receiving solely corticosteroids were excluded.

DATA EXTRACTION

Primary outcomes were pure-tone audiometry and speech discrimination scores at baseline and after DMARD treatment. Secondary outcomes were rates of subjective audiovestibular complaints and rates of adverse reactions. No objective vestibular outcomes underwent meta-analysis.

DATA SYNTHESIS

Mean differences were calculated using RevMan 5.4. Heterogeneity was assessed with the Q test and I2 statistic. Pooled prevalence rates of audiovestibular symptoms were expressed as a percentage with 95% confidence intervals.

RESULTS

Ten studies with a total of 187 patients were included. Treatments included methotrexate, etanercept, azathioprine, anakinra, cyclophosphamide, rituximab, and infliximab. Mean treatment duration was 10.8 ± 22.2 months and mean follow-up was 13.7 ± 8.1 months. The pure-tone audiometry and speech discrimination scores mean differences between baseline and post-DMARD were -2.1 [-4.1, -0.1] dB and 13.9 [8.5, 19.4] %, respectively. Seven studies reported 38 adverse events, four of which were classified as serious.

CONCLUSION

DMARDs showed statistically significant improvement in auditory outcomes, as well as subjective symptoms, with relatively low rates of adverse events. They warrant further exploration to better compare with corticosteroids.

Temporal and regulatory dynamics of the inner ear transcriptome during development in mice

The inner ear controls hearing and balance, while the temporal molecular signatures and transcriptional regulatory dynamics underlying its development are still unclear. In this study, we investigated time-series transcriptome in the mouse inner ear from embryonic day 11.5 (E11.5) to postnatal day 7 (P7) using bulk RNA-Seq. A total of 10,822 differentially expressed genes were identified between pairwise stages. We identified nine significant temporal expression profiles using time-series expression analysis. The constantly down-regulated profiles throughout the development are related to DNA activity and neurosensory development, while the constantly upregulated profiles are related to collagen and extracellular matrix. Further co-expression network analysis revealed that several hub genes, such as Pnoc, Cd9, and Krt27, are related to the neurosensory development, cell adhesion, and keratinization. We uncovered three important transcription regulatory paths during mice inner ear development. Transcription factors related to Hippo/TGFβ signaling induced decreased expressions of genes related to the neurosensory and inner ear development, while a series of INF genes activated the expressions of genes in immunoregulation. In addition to deepening our understanding of the temporal and regulatory mechanisms of inner ear development, our transcriptomic data could fuel future multi-species comparative studies and elucidate the evolutionary trajectory of auditory development.

Autoimmune disease of head and neck, imaging, and clinical review

Autoimmune disease of the head and neck (H&N) could be primary or secondary to systemic diseases, medications, or malignancies. Immune-mediated diseases of the H&N are not common in daily practice of radiologists; the diagnosis is frequently delayed because of the non-specific initial presentation and lack of familiarity with some of the specific imaging and clinical features. In this review, we aim to provide a practical diagnostic approach based on the specific radiological findings for each disease. We hope that our review will help radiologists expand their understanding of the spectrum of the discussed disease entities, help them narrow the differential diagnosis, and avoid unnecessary tissue biopsy when appropriate based on the specific clinical scenarios.

Idiopathic sudden sensorineural hearing loss: A critique on corticosteroid therapy

Idiopathic sudden sensorineural hearing loss (ISSNHL) is a condition affecting 5-30 per 100,000 individuals with the potential to significantly reduce one's quality of life. The true incidence of this condition is not known because it often goes undiagnosed and/or recovers within a few days. ISSNHL is defined as a ≥30 dB loss of hearing over 3 consecutive audiometric octaves within 3 days with no known cause. The disorder is typically unilateral and most of the cases spontaneously recover to functional hearing within 30 days. High frequency losses, ageing, and vertigo are associated with a poorer prognosis. Multiple causes of ISSNHL have been postulated and the most common are vascular obstruction, viral infection, or labyrinthine membrane breaks. Corticosteroids are the standard treatment option but this practice is not without opposition. Post mortem analyses of temporal bones of ISSNHL cases have been inconclusive. This report analyzed ISSNHL studies administering corticosteroids that met strict inclusion criteria and identified a number of methodologic shortcomings that compromise the interpretation of results. We discuss the issues and conclude that the data do not support present treatment practices. The current status on ISSNHL calls for a multi-institutional, randomized, double-blind trial with validated outcome measures to provide science-based treatment guidance.

Cochlear implantation in systemic autoimmune disease

PURPOSE OF REVIEW

Autoimmune inner ear disease (AIED) is a rare, but likely underrecognized cause of hearing loss. However, hearing loss is common in systemic autoimmune disease and it is important for the clinician to be familiar with the spectrum of disease. In this article, we will review the developments in diagnosis and management of AIED, with a focus on the outcomes and potential pitfalls of cochlear implantation.

RECENT FINDINGS

Hearing loss in AIED tends to be progressive and bilateral, but up to 40% can present as sudden hearing loss and one-third can present unilaterally. HSP-70 serology may help with diagnosis and may predict steroid response. Cochlear implantation provides excellent hearing and quality of life outcomes in patients deafened by AIED. Intracochlear fibrosis/ossification is found intraoperatively in the majority (54%) of patients undergoing cochlear implantation. A large percentage (32%) of patients has fluctuating impedances postimplantation, which may interfere with implant performance and mapping.

SUMMARY

Diagnosis of AIED is largely clinical, and a strong index of suspicion is required. Multidisciplinary care is crucial for optimal management. Cochlear implant outcomes are generally excellent, but the clinician needs to be cognizant of the pitfalls of encountering intracochlear fibrosis intraoperatively and likelihood of implant performance fluctuation related to ongoing inflammation in the cochlea.

Serum Fibrinogen Level and Cytokine Production as Prognostic Biomarkers for Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVES

No clinically useful prognostic factors have been identified for idiopathic sudden sensorineural hearing loss (ISSNHL). The current study therefore sought to identify useful prognostic factors for idiopathic sudden sensorineural hearing loss from blood biomarkers while attempting to classify the pathogenic mechanism and formulate treatment strategies based on these results.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary referral center.

METHODS

A total of 47 patients with acute phase ISSNHL were treated with steroid at an initial dose of 1 mg/kg/day and hyperbaric oxygen therapy and followed up for 6 months. Serum fibrinogen levels, peripheral blood mononu- clear cells (PBMCs), and interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α production levels from PBMCs were measured, after which patient's pre- and post- treatment hearing was compared.

RESULTS

In the overall cohort, the mean improvement level, mean recovery rate, and mean fibrinogen level was 20.3 dB, 46.2%, 292.0 mg/mL, respectively. The mean levels of IL-1β, IL-6, and TNF-α produced by peripheral blood mononu- clear cells cultured under lipopolysaccharide stimulation were 318.4, 498.1, and 857.6 pg/mL, respectively. High fibrinogen levels were associated with poor hearing progno- sis. Lipopolysaccharide-stimulated cytokine production by PBMCs did not correlate with hearing changes; however, the prognosis was significantly better in patients with low fibrinogen levels and high IL-1β levels produced by PBMCs than in other patients.

CONCLUSIONS

Our results suggest that patients with simple inflammatory-type ISSNHL responded well to standard therapy. Therefore, serum fibrinogen levels and PBMCs cytokine production may help determine the management of ISSNHL based on its pathogenic mechanism.

Role of Inner Ear Macrophages and Autoimmune/Autoinflammatory Mechanisms in the Pathophysiology of Inner Ear Disease

Macrophages play important roles in tissue homeostasis and inflammation. Recent studies have revealed that macrophages are dispersed in the inner ear and may play essential roles in eliciting an immune response. Autoinflammatory diseases comprise a family of immune-mediated diseases, some of which involve sensorineural hearing loss, indicating that similar mechanisms may underlie the pathogenesis of immune-mediated hearing loss. Autoimmune inner ear disease (AIED) is an idiopathic disorder characterized by unexpected hearing loss. Tissue macrophages in the inner ear represent a potential target for modulation of the local immune response in patients with AIED/autoinflammatory diseases. In this review, we describe the relationship between cochlear macrophages and the pathophysiology of AIED/autoinflammatory disease.

Autoimmune Vestibulopathy—A Case Series

Autoimmune inner ear disease (AIED) is a rare clinical entity. Its pathogenicity, heterogenous clinical presentation in the context of secondary systemic autoimmune disease and optimal treatment avenues remain poorly understood. Vestibular impairment occurring in the context of AIED is rarely subject to detailed investigation given that the auditory symptoms and their responsiveness to immunosuppression are the focus of the few proposed diagnostic criteria for AIED. We present three cases of vestibulopathy occurring in the context of autoimmune inner ear conditions, including the first known report of autoimmune inner ear pathology arising with a temporal association to administration of the Pfizer-BioNTech SARS-CoV2 vaccination. We review the available literature pertinent to each case and summarise the key learning points, highlighting the variable presentation of vestibular impairment in AIED.

Transcriptome analysis of the early stage ifnlr1-mutant zebrafish indicates the immune response to auditory dysfunction

BACKGROUND

IFNLR1 has been recently identified to be related to autosomal dominant nonsyndromic sensorineural hearing loss (ADNSHL). It is reported to be expressed in the inner ear of mice and the lateral line of zebrafish. However, it remains unclear how defects in this gene lead to hearing loss.

OBJECTIVES

To elucidate the global gene expression changes in zebrafish when the expression of ifnlr1 is downregulated.

METHODS

Transcriptome analysis was performed on ifnlr1 morpholino knockdown zebrafish and the control zebrafish using RNA-seq technology.

RESULTS

The results show that 262 differentially expressed genes (DEGs) were up-regulated while 146 DEGs were down-regulated in the E4I4-Mo zebrafish larvae compared to the control-Mo. Six pathways were significantly enriched, including steroid biosynthesis pathway, adipocytokine signaling pathway, cytokine-cytokine receptor interaction pathway, p53 signaling pathway, AGE-RAGE signaling pathway in diabetic complications, and terpenoid backbone biosynthesis pathway. Among them, three pathways (steroid biosynthesis pathway, cytokine-cytokine receptor interaction pathway and p53 signaling pathway) are immune-associated.

CONCLUSIONS

The transcriptome analysis results contribute to the groundwork for future research on the pathogenesis of IFNLR1-associated hearing loss.

Hearing restoration and the stria vascularis: evidence for the role of the immune system in hearing restoration

PURPOSE OF REVIEW

This article reviews the current literature regarding the pathogenesis of immune-mediated sensorineural hearing loss, utilizes previously published single-nucleus transcriptional profiles to characterize cytokine and cytokine receptor expression in the adult stria vascularis cell types to support immune system interaction with the stria vascularis and reviews the current literature on immunomodulatory agents currently being used for hearing-restoration treatment.

RECENT FINDINGS

The literature review highlights recent studies that elucidate many cytokines and immune markers, which have been linked to various immune-mediated disease processes that have been observed with sensorineural hearing loss within the stria vascularis and highlights recent publications studying therapeutic targets for these pathways.

SUMMARY

This review highlights the current literature regarding the pathogenesis of immune-mediated hearing loss. The role of cochlear structures in human temporal bones from patients with immune-mediated sensorineural hearing loss are highlighted, and we review cytokine signalling pathways relevant to immune-mediated sensorineural hearing loss and localize genes encoding both cytokine and cytokine receptors involved in these pathways. Finally, we review immunomodulatory therapeutics in light of these findings and point to opportunities for the application of novel therapeutics by targeting these signalling pathways.

Cochlear signal alterations using pseudo-color perceptual enhancement for patients with sensorineural hearing loss

BACKGROUND

Neuroimaging detection of sensorineural hearing loss (SNHL)-related temporal bone abnormalities is limited (20-50%). We hypothesize that cochlear signal differences in gray-scale data may exceed the threshold of human eye detection. Gray-scale images can be post-processed to enhance perception of tonal difference using "pseudo-color" schemes.

OBJECTIVE

To compare patients with unilateral SNHL to age-matched normal magnetic resonance imaging (MRI) exams for "labyrinthine color differences" employing pseudo-color post-processing.

MATERIALS AND METHODS

The MRI database at an academic children's hospital was queried for "hearing loss." Only unilateral SNHL cases were analyzed. Sixty-nine imaging exams were reviewed. Thirteen age-matched normal MR exams in children without hearing loss were chosen for comparison. Pseudo-color was applied with post-processing assignment of specific hues to each gray-scale intensity value. Gray-scale and pseudo-color images were qualitatively evaluated for signal asymmetries by a board-certified neuroradiologist blinded to the side of SNHL.

RESULTS

Twenty-six SNHL (mean: 7.6±3 years) and 13 normal control exams (mean: 7.3±4 years) were included. All patients had normal gray-scale cochlear signal and all controls had symmetrical pseudo-color signal. However, pseudo-color images revealed occult asymmetries localizing to the SNHL ear with lower values in 38%. Ninety-one percent of these cases showed concordance between the side of pseudo-color positivity and the side of hearing loss.

CONCLUSION

Pseudo-color perceptual image enhancement reveals intra-labyrinthine fluid alterations on MR exams in children with unilateral SNHL. Pseudo-color image enhancement techniques improve detection of cochlear pathology and could have therapeutic implications.

Biologics in Otolaryngology: Past, Present, and Future

Biologics have been widely adopted in multiple subspecialties of otolaryngology. This article provides an overview of past, present, and future uses of biologics in otolaryngology with emphasis on allergic rhinitis, chronic rhinosinusitis with polyposis, head and neck squamous cell carcinoma, salivary and skull base tumors, hearing loss, and other otologic disorders.

Hearing loss in inner ear and systemic autoimmune disease: A systematic review of post-cochlear implantation outcomes

OBJECTIVES

To assess outcomes following cochlear implantation (CI) in patients with hearing loss secondary to primary or secondary autoimmune inner ear disease (AIED).

METHODS

A systematic review and narrative synthesis was completed according to PRISMA guidelines. Databases searched included MEDLINE, PubMed, EMBASE, Web of Science, Cochrane Collection, and ClinicalTrials.gov. No limits were placed on year of publication or language.

RESULTS

A total of 551 studies were identified, of which 29 were included after removal of duplicates, and screening the title, abstract, and full text. All except one study were OCEBM grade IV. 114 of 115 patients displayed improvement in hearing following cochlear implantation. With implant use, roughly a third of these patients had hearing that improved over time, a third improved and plateaued, and a third remained stable. There was no additional risk of perioperative complications found in AIED patients compared what is generally accepted in general cochlear implantation, although two episodes of device failure after 6 months were noted, and four patients with secondary AIED displayed poor initial audiological outcomes.

CONCLUSION

CI in both primary and secondary AIED provides marked improvement in hearing. Early CI may be a valid management option, provide long-lasting hearing in patients and reduce the side effects of long-term systemic immunosuppressants. However, patients should be counseled residual hearing may be lost if there is cochlear ossification or fibrosis which may make implant insertion more traumatic.

LEVEL OF EVIDENCE

NA.

Intratympanic Lipopolysaccharide Elevates Systemic Fluorescent Gentamicin Uptake in the Cochlea

Objectives/Hypothesis

Lipopolysaccharide (LPS), a key component of bacterial endotoxins, activates macrophages and triggers the release of inflammatory cytokines in mammalian tissues. Recent studies have shown that intratympanic injection of LPS simulates acute otitis media (AOM) and results in morphological and functional changes in the inner ear. Here we established an AOM mouse model with LPS to investigate the uptake of ototoxic gentamicin in the inner ear, and elucidated the underlying mechanism by focusing on cochlear inflammation as a result of AOM.

Study Design

Preclinical rodent animal model.

Methods

Fluorescently tagged gentamicin (GTTR) was systemically administered to mice with AOM. Iba1‐positive macrophage morphology and inner ear cytokine profile were evaluated by immunofluorescence technique and a mouse cytokine array kit, respectively.

Results

We observed characteristic symptoms of AOM in the LPS‐treated ears with elevated hearing thresholds indicating a conductive hearing loss. More importantly, the LPS‐induced AOM activated cochlear inflammatory responses, manifested by macrophage infiltration, particularly in the organ of Corti and the spiral ligament, in addition to the up‐regulation of proinflammatory cytokines. Meanwhile, GTTR uptake in the stria vascularis and sensory hair cells from all the LPS‐treated ears was significantly enhanced at 24, 48, and 72‐hour post‐treatment, as the most prominent enhancement was observed in the 48‐hour group.

Conclusion

In summary, this study suggests that the pathological cochlea is more susceptible to ototoxic drugs, including aminoglycosides, and justified the clinical concern of aminoglycoside ototoxicity in the AOM treatment. Laryngoscope, 131:E2573–E2582, 2021

Granulomatosis with Polyangiitis as a Cause of Sudden-Onset Bilateral Sensorineural Hearing Loss: Case Report and Recommendations for Initial Assessment

Granulomatosis with polyangiitis (GPA) is a severe systemic vasculitis that commonly affects the paranasal sinuses, upper and lower respiratory tracts, and kidneys. GPA has also been associated with sensorineural hearing loss (SNHL), through inflammation of the cochlear apparatus. Early recognition, diagnostic laboratory evaluation, and appropriate treatment are essential to improve outcomes and achieve remission for patients with GPA. Here, we present a case of bilateral sudden sensorineural hearing loss (SSNHL) and distal symmetric polyneuropathy as the first presenting signs of GPA. A specific diagnostic work-up to rule out autoimmune inner-ear disease in patients with bilateral SSNHL is not clearly stated in the clinical practice guidelines from the American Academy of Otolaryngology-Head and Neck Surgery. The aim of this paper is to delineate an appropriate diagnostic work-up for patients with bilateral SSNHL when there is concern for autoimmune disease.

Sensorineural Hearing Loss and Systemic Autoimmune Disease: The Experience of a Systemic Immune-Mediated Diseases Unit

Background

Autoimmune inner ear disease (AIED) represents less than 1% of all cases of sensorineural hearing loss (SNHL) but its frequency may be underestimated due to lack of specific clinical and laboratory criteria. AIED can be associated with a systemic autoimmune disease (SAID) in 15%-30% of the cases. The objective of the present study was to characterize the clinical and prognostic factors of a cohort of patients with AIED.

Materials and methods

The authors conducted a retrospective descriptive analysis of a cohort of patients with AIED referred from the otorhinolaryngology department to a systemic immune-mediated diseases unit between March 2013 and November 2020. A consecutive sample of 39 patients with suspected AIED was referred. SNHL was defined as a fall of the hearing threshold of at least 30 decibels in three consecutive frequencies. Eight patients were excluded for not meeting the audiometric criteria or having confounding factors. The remaining 31 patients were included with a total of 50 affected ears. To classify the intensity of hearing loss, an arithmetic mean of pure tone was calculated. Normal hearing or mild hearing loss at the last pure tone audiometry of the follow-up were an indicator of good prognosis and were considered the outcome of interest.

Results

Thirty-two percent of the patients had an associated SAID. There were no differences regarding demographic and clinical characteristics when comparing patients with AIED alone and patients with AIED and a SAID, except for the positivity of antinuclear antibodies (ANA). ANA positivity was superior in patients with the association of AIED and a SAID when compared with patients with AIED alone (90% vs 50%; p=0.037). The SAID was diagnosed after the AIED in 70% of the patients, in which diagnosis of the SAID occurred a median of 4,2 (IQR 0.8-5.1) years after the diagnosis of the AIED. Normal audiometric evaluation or a mild hearing loss was achieved in 31% of the ears at the last audiometric evaluation. A normal audiometry or a mild hearing loss at the time of diagnosis was independently associated with a better outcome (31%, 14%, CI 1.71-273.69; p=0.018). Bilateral hearing loss was independently associated with a worse outcome (54%, 79%, CI 0.01-0.84; p=0.035). The use of systemic corticosteroids (p=0.941), transtympanic corticosteroids (p=0.700) and non-steroid immunomodulator drugs (p=0.986) did not affect prognosis. The presence of a SIAD did not affect the prognosis (p=0.986).

Conclusions

In this cohort, SAID was present in one-third of the patients with AIED. A good prognosis was achieved in one-third of the patients. A normal audiometry or mild disease at presentation was associated with a good outcome, whilst bilateral involvement was associated with a bad one. Association of a SAID did not seem to influence the hearing-related prognosis. Positivity of ANA antibodies may justify performing a complementary investigation to determine the presence of a SAID.

The Pathogenesis of secondary forms of Autoimmune Inner Ear Disease (AIED): advancing beyond the audiogram data

INTRODUCTION

Autoimmune Inner Ear Disease (AIED) can be of a primary or secondary type. To date, a clear pathogenesis of the disease is still not available. Focusing on the secondary forms of AIED, the aim of this review is to (i) assess and describe the hearing involvement in patients affected by autoimmune diseases, (ii) describe the possible association between clinical features (among serological/laboratory data and disease activity/duration) and hearing impairment, (iii) show evidence connecting the AIED types with various etiopathogenetic mechanisms.

AREAS COVERED

A PRISMA-compliant systematic review was performed. Medline, Cochrane, Embase, and Cinahl were searched from 1 January 2015 through to 5 August 2020. Overall, 16 studies (involving 1043 participants) were included in the review. The data in the literature suggested that bilateral mild-to-moderate sensorineural hearing loss is a commonly reported clinical symptom of AIED.

EXPERT OPINION

Patients with systemic autoimmune disorders present a cochlear injury which might be associated with the humoral and/or cellular immune response against the inner ear. To date, AIED pathogenesis remains an open issue, due to the rarity of these clinical entities and due to the difficulties in investigating the inner ear immunology, considering the inner ear inaccessibility for tissue sampling.

Assessment of Visual and Brainstem Auditory Evoked Potentials in Patients with Hashimoto's Thyroiditis

BACKGROUND

The present study was aimed to evaluate parameters of visual and brainstem auditory evoked potentials (VEP, BAEP) in euthyreotic Hashimoto's thyroiditis (HT) patients without central nervous system involvement.

METHODS

100 HT patients (92 women, 8 men), mean age 46.9 years, and 50 healthy controls. They underwent a neurological examination, thyroid hormone levels, thyroid autoantibody titers, and brain imaging. Latencies and amplitudes of the N75, P100, and N145 component of VEP and the I-V components of BAEP were analyzed.

RESULTS

The neurological examination revealed in 31 patients signs of increased neurovegetative excitability. Brain resonance imaging showed no abnormalities in HT patients. The mean P100, relative P100, and N145 VEP latencies were significantly longer, and P100 amplitude significantly higher in HT patients than the controls. HT patients also had a longer mean wave BAEP V latency and mean wave III-V and I-V interpeak latencies, and significantly lower mean wave I and V amplitudes. Abnormal VEP and BAEP were recorded in 34% of the patients. There were no statistically significant correlations between the mean VEP parameters and thyroid profile and the applied dose of L-thyroxine. There was a relationship between the level of TSH and the wave BAEP III-V interpeak latency.

CONCLUSIONS

There were changes in the brain's bioelectrical activity in one-third of the patients with HT without nervous system involvement. The increased amplitude of the VEP may indicate increased cerebral cortex activity. Disorders of the brain's bioelectrical activity in the course of HT may be associated with an autoimmune process.

On the Role of Fibrocytes and the Extracellular Matrix in the Physiology and Pathophysiology of the Spiral Ligament

The spiral ligament in the cochlea has been suggested to play a significant role in the pathophysiology of different etiologies of strial hearing loss. Spiral ligament fibrocytes (SLFs), the main cell type in the lateral wall, are crucial in maintaining the endocochlear potential and regulating blood flow. SLF dysfunction can therefore cause cochlear dysfunction and thus hearing impairment. Recent studies have highlighted the role of SLFs in the immune response of the cochlea. In contrast to sensory cells in the inner ear, SLFs (more specifically type III fibrocytes) have also demonstrated the ability to regenerate after different types of trauma such as drug toxicity and noise. SLFs are responsible for producing proteins, such as collagen and cochlin, that create an adequate extracellular matrix to thrive in. Any dysfunction of SLFs or structural changes to the extracellular matrix can significantly impact hearing function. However, SLFs may prove useful in restoring hearing by their potential to regenerate cells in the spiral ligament.

Inflammation associated with noise-induced hearing loss

Inflammation is a complex biological response to harmful stimuli including infection, tissue damage, and toxins. Thus, it is not surprising that cochlear damage by noise includes an inflammatory component. One mechanism by which inflammation is generated by tissue damage is the activation of damage-associated molecular patterns (DAMPs). Many of the cellular receptors for DAMPS, including Toll-like receptors, NOD-like receptors, and DNA receptors, are also receptors for pathogens, and function in the innate immune system. DAMP receptors are known to be expressed by cochlear cells, and binding of molecules released by damaged cells to these receptors result in the activation of cell stress pathways. This leads to the generation of pro-inflammatory cytokines and chemokines that recruit pro-inflammatory leukocytes. Extensive evidence indicates pro-inflammatory cytokines including TNF alpha and interleukin 1 beta, and chemokines including CCL2, are induced in the cochlea after noise exposure. The recruitment of macrophages into the cochlea has also been demonstrated. These provide substrates for noise damage to be enhanced by inflammation. Evidence is provided by the effectiveness of anti-inflammatory drugs in ameliorating noise-induced hearing loss. Involvement of inflammation provides a wide variety of additional anti-inflammatory and pro-resolution agents as potential pharmacological interventions in noise-induced hearing loss.

Patient-reported involvement of the eighth cranial nerve in giant cell arteritis

INTRODUCTION

The frequency of eighth nerve lesions in patients with giant cell arteritis (GCA) has rarely been examined. However, sudden onset deafness has been recorded as a presenting feature of GCA on several occasions. This study sought to establish how common this and other symptoms of eighth nerve involvement are in a large retrospective survey.

METHODS

We contacted 170 patients with GCA and 250 matched PMR patients, inviting them to participate in a questionnaire survey of symptoms of eighth nerve dysfunction. We compared the presence of deafness, tinnitus, loss of balance and vertigo in both groups and examined the relationship between the onset of these symptoms and other features of GCA.

RESULTS

A total of 317 patients were recruited. The percentage of patients with symptoms of possible vestibulocochlear disease prior to commencement of steroid therapy was significantly greater among GCA patients than PMR patients for all domains. Hearing loss which was twice as common in GCA as in PMR (53% vs 26%) [p = 0.001]. Deafness was concurrent in 35% of GCA patients with other symptoms and 45% reported colocation with headache. Recovery with steroids occurred in 56% of these.

CONCLUSION

Symptoms of eighth nerve dysfunction are present in over half of patients with GCA. Recovery with steroids was predicted by concurrence with headache in terms of both timing and location. It appears that eighth nerve involvement, especially acute hearing loss, is a not infrequent feature of GCA and often responds well to steroid therapy. Clinicians should enquire about these symptoms when evaluating a patient for possible GCA.Key Points• Deafness is a frequent presenting feature of giant cell arteritis.• Vertigo, tinnitus and loss of balance are also often reported by GCA sufferers.• Steroid therapy is more likely to relieve these symptoms if they are ipsilateral and concurrent with headache.

miR‑10b‑3p, miR‑8112 and let‑7j as potential biomarkers for autoimmune inner ear diseases

Circulating microRNAs (miRNAs) have been suggested as non‑invasive biomarkers for the diagnosis of several autoimmune diseases. However, to the best of our knowledge, no studies have yet examined the miRNA expression profiles in autoimmune inner ear disease (AIED). The present study aimed to use an miRNA sequencing assay to detect the miRNA expression profiles of serum samples from 3 control mice and 3 antigen‑induced AIED model mice. Differentially expressed miRNAs (DE‑miRNAs) were screened using a t‑test. miRNA target prediction was performed using TargetScan Mouse. Then, the miRNA‑target gene interaction network was constructed and visualized using Cytoscape software. The underlying functions of the target genes of the DE‑miRNAs were predicted using the clusterProfiler package. As a result, 22 miRNAs were identified as DE‑miRNAs between AIED and control mice, including 10 upregulated and 12 downregulated genes. Based on the TargetScan Mouse prediction, 1,958 genes were identified as the targets for the 22 DE‑miRNAs. Functional analysis indicated that only the target genes of 8 miRNAs were respectively enriched for Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways, among which miR‑10b‑3p, let‑7j and miR‑8112 were shared between the two pathway analyses. These 3 miRNAs may be involved in AIED by affecting inflammatory chemokine (miR‑10b‑3p‑C‑C motif chemokine 12), Wnt signaling (miR‑8112‑Wnt9b/Wnt 3a/Wnt2b) and Mucin type O‑glycan biosynthesis pathways (let‑7j‑Galnt2/Galnt12). In conclusion, miR‑10b‑3p, miR‑8112 and let‑7j may be underlying biomarkers for diagnosing AIED.

Harderian gland-derived stem cells as a cytotherapy in a guinea pig model of carboplatin-induced hearing loss

BACKGROUND

Stem cells therapy of hearing loss is a challenging field due to lacking self-regenerative capacity of cochlea. Harderian gland of guinea pigs was thought to harbour a unique type of progenitors which could restore the damaged cochlear tissues.

THE AIM

of this study was to isolate Harderian gland derived stem cells (HG-SCs) and investigate their efficacy in restoring the damaged cochlear tissue in carboplatin-induced hearing loss.

METHODOLOGY

Sixty female and 10 male pigmented guinea pigs were used; the male animals were HG-SCs donors, while the females were assigned into 3 groups; control, hearing loss (HL) and HG-SC-treated groups. Auditory reflexes were assessed throughout the study. The animals were euthanized 35 days after HG-SCs transplantation, the cochleae were extracted and processed for assessment by light microscope and scanning electron microscope. Morphometric assessment of stria vascularis thickness, hair cells and spiral ganglia neuronal number and optical density of TLR4 expression were done.

RESULTS

The isolated HG-SCs had the same morphological and phenotypical character as mesenchymal stem cells. HL group revealed destruction of organ of Corti, stria vascularis and spiral ganglion with decreased morphometric parameters. Restoration of both cochlear structure and function was observed in HG-SC-treated group along with a significant increase in IHCs, OHCs numbers, stria vascularis thickness and spiral ganglionic cell count to be close to the values of control group.

CONCLUSION

The isolated HG-SCs were proved to restore structure and function of cochlea in guinea pig model of hearing loss.

Association Between Psoriasis with Arthritis and Hearing Impairment in US Adults: Data from the National Health and Nutrition Examination Survey

Objective.

Emerging data has linked inflammatory arthritis with hearing impairment (HI). The objective of this study was to investigate the relationship between psoriasis with arthritis (PsA) and HI in the US population. Given the known association of HI and depression, a secondary aim is to investigate the effect of PsA on mental well-being.

Methods.

Cross-sectional study using the National Health and Nutrition Examination Survey for adults aged ≥ 20 years (n = 10,747). Association of PsA with above outcomes was examined using multivariable generalized linear and ordinal logistic regression models, adjusted for demographics and medical comorbidities. Structural equation models examined the extent to which HI mediated the effect of PsA on mental health.

Results.

Individuals with PsA were more likely to report hearing difficulties (OR 1.50, p = 0.043), visit a mental health provider (OR 1.62, p = 0.084), have 1.62 more days of poor mental health over the previous month (p = 0.033), and have depression (OR 2.01, p = 0.015) compared to controls. HI mediated 6.5%, 8.3%, and 5.0% of the effect of PsA on the above mental health outcomes, respectively.

Conclusion.

PsA is independently associated with a significantly increased risk of HI, which partially mediates an association with worsened psychiatric outcomes.

Middle-ear dexamethasone delivery via ultrasound microbubbles attenuates noise-induced hearing loss

OBJECTIVES/HYPOTHESIS

In this study, we expanded our previous investigation by testing the efficiency of trans-round window membrane dexamethasone (DEX) delivery mediated by ultrasound (US)-aided microbubbles (MBs) and its preventive effects regarding noise exposure in animal models.

STUDY DESIGN

Live animal model.

METHODS

Forty-two pigmented male guinea pigs were divided into the following three groups: an US-MBs (USM) group, in which the tympanic bulla was filled with DEX and MBs and exposed to US; a round window soaking (RWS) group, without the US irradiation; and a control group. The above-mentioned manipulations were performed 2 hours prior to white noise exposure. The cochlear damage, including auditory threshold shifts, hair cell loss, and expression of cochlear HMGB1, was evaluated.

RESULTS

The enhanced DEX delivery efficiency of the USM group was approximately 2.4× to 11.2× greater than that of the RWS group. After the noise exposure, the RWS group showed significant cochlear protection compared with the control group, and more significant and dominant protective effects were demonstrated in the USM group.

CONCLUSIONS

The application of US-MBs provides a safe and more effective approach than spontaneous diffusion, which is commonly used in clinical practice; thus, this technique holds potential for future inner-ear drug delivery.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:1907-1914, 2019.

Update on Vertigo in Autoimmune Disorders, from Diagnosis to Treatment

The prevalence of autoimmune diseases has been increasing over the last 20 years. The clinical presentation of this large and heterogeneous group of disorders depends on whether the involvement is organ-specific or non-organ-specific. Dizziness, vertigo, and disequilibrium are common symptoms reported by patients with vestibulocochlear involvement. The association of vertigo and autoimmune diseases has been largely documented, suggesting that autoimmune disorders could be overrepresented in patients with vertigo in comparison to the general population. The aim of this review is to present the recent literature findings in the field of autoimmune-mediated diseases with cochleovestibular involvement, focusing on the clinical presentation, diagnosis, and treatment of immune-mediated inner ear diseases including autoimmune inner ear disease (AIED), Meniere's disease, and bilateral vestibulopathy, as well as of systemic autoimmune diseases with audiovestibular disorders, namely, Behçet's disease, Cogan's syndrome, sarcoidosis, autoimmune thyroid disease, Vogt-Koyanagi-Harada syndrome, relapsing polychondritis, systemic lupus erythematosus, antiphospholipid syndrome, IgG4-related disease, and ANCA-associated vasculitides.

Screening of genes associated with inflammatory responses in the endolymphatic sac reveals underlying mechanisms for autoimmune inner ear diseases

The current study analyzed gene expression profiles of the endolymphatic sac (ES) in rats and identified expressed genes, present in the human and rat ES, to reveal key hubs for inflammatory responses. Microarray data (accession no. E-MEXP-3022) were obtained from the European Bioinformatics Institute database, including three biological replicates of ES plus dura tissues and three replicates of pure dura tissues form rats. Differentially expressed genes (DEGs) were screened using the Linear Model for Microarray data method and a protein-protein interaction (PPI) network was constructed using data from the Search Tool for the Retrieval of Interacting Genes/Proteins database followed by a module analysis via Clustering with Overlapping Neighborhood Expansion. Function enrichment analysis was performed using the Database for Annotation, Visualization and Integrated Discovery online tool. A total of 612 DEGs were identified, including 396 upregulated and 216 downregulated genes. Gene ontology term enrichment analysis indicated DEGs were associated with cell adhesion, including α5-integrin (Itga1) and secreted phosphoprotein 1 (Spp1); T cell co-stimulation, including C-C chemokine ligand (Ccl)21 and Ccl19; and the toll-like receptor signaling pathway, including toll-like receptor (Tlr)2, Tlr7 and Tlr8. These conclusions were supported by Kyoto Encyclopedia of Genes and Genomes pathway analyses revealing extracellular matrix-receptor interaction, including Itga1 and Spp1; leukocyte transendothelial migration, includingclaudin-4 (Cldn4); and malaria, including Tlr2. The hub roles of Itga1, Cd24 and Spp1 were revealed by calculating three topological properties of the PPI network. Ccl21, Ccl19 and Cldn4 were demonstrated to be crucial following significant module analysis according to the corresponding threshold, which revealed they were enriched in inflammation pathways. Tlr7, Tlr2, granzyme m and Tlr8 were common genes associated with inflammatory responses in rat and human ES. In conclusion, abnormal expression of the aforementioned inflammation-associated genes may be associated with the development of autoimmune inner ear diseases.

Autoimmune inner ear disease secondary to Hashimoto's thyroiditis: a case report

Autoimmune inner ear disease is an important yet incompletely understood cause of hearing loss which can present to different medical disciplines. Its diagnostic significance is indicated by the fact that it is a reversible medical condition if recognized early with an excellent response to immunosuppressive agents. Therefore, it should be considered in the differential diagnosis of hearing disorders especially in the context of another autoimmune disease such as Hashimoto’s thyroiditis.

Inner Ear Hair Cell Protection in Mammals against the Noise-Induced Cochlear Damage

Inner ear hair cells are mechanosensory receptors that perceive mechanical sound and help to decode the sound in order to understand spoken language. Exposure to intense noise may result in the damage to the inner ear hair cells, causing noise-induced hearing loss (NIHL). Particularly, the outer hair cells are the first and the most affected cells in NIHL. After acoustic trauma, hair cells lose their structural integrity and initiate a self-deterioration process due to the oxidative stress. The activation of different cellular death pathways leads to complete hair cell death. This review specifically presents the current understanding of the mechanism exists behind the loss of inner ear hair cell in the auditory portion after noise-induced trauma. The article also explains the recent hair cell protection strategies to prevent the damage and restore hearing function in mammals.

Immune cells and non-immune cells with immune function in mammalian cochleae

The cochlea has an immune environment dominated by macrophages under resting conditions. When stressed, circulating monocytes enter the cochlea. These immune mediators, along with cochlear resident cells, organize a complex defense response against pathological challenges. Since the cochlea has minimal exposure to pathogens, most inflammatory conditions in the cochlea are sterile. Although the immune response is initiated for the protection of the cochlea, off-target effects can cause collateral damage to cochlear cells. A better understanding of cochlear immune capacity and regulation would therefore lead to development of new therapeutic treatments. Over the past decade, there have been many advances in our understanding of cochlear immune capacity. In this review, we provide an update and overview of the cellular components of cochlear immune capacity with a focus on macrophages in mammalian cochleae. We describe the composition and distribution of immune cells in the cochlea and suggest that phenotypic and functional characteristics of macrophages have site-specific diversity. We also highlight the response of immune cells to acute and chronic stresses and comment on the potential function of immune cells in cochlear homeostasis and disease development. Finally, we briefly review potential roles for cochlear resident cells in immune activities of the cochlea.

Otic drug delivery systems: formulation principles and recent developments

Disorders of the ear severely impact the quality of life of millions of people, but the treatment of these disorders is an ongoing, but often overlooked challenge particularly in terms of formulation design and product development. The prevalence of ear disorders has spurred significant efforts to develop new therapeutic agents, but perhaps less innovation has been applied to new drug delivery systems to improve the efficacy of ear disease treatments. This review provides a brief overview of physiology, major diseases, and current therapies used via the otic route of administration. The primary focuses are on the various administration routes and their formulation principles. The article also presents recent advances in otic drug deliveries as well as potential limitations. Otic drug delivery technology will likely evolve in the next decade and more efficient or specific treatments for ear disease will arise from the development of less invasive drug delivery methods, safe and highly controlled drug delivery systems, and biotechnology targeting therapies.

Autoimmune Inner Ear Disease: Immune Biomarkers, Audiovestibular Aspects, and Therapeutic Modalities of Cogan's Syndrome

Cogan's syndrome (CS) is a rare autoimmune disorder characterized by audiovestibular dysfunction and ocular inflammation. Currently, there is no specific serum autoantibody used in the diagnostic workup of CS. Treatment is based on immunosuppressive agents, mainly corticosteroids as first-line choice. Recently, novel therapeutic modalities in CS have emerged. These include tumor necrosis factor-α inhibitors and other biologicals. Despite medical treatment, hearing loss may progress to irreversible bilateral profound SNHL in approximately half of CS patients resulting in candidacy for cochlear implantation (CI). Due to the inflammatory nature of the disease that is causing endosteal reaction with partial obliteration or complete neoossification of the intracochlear ducts, early CI is recommended. CI provides excellent and stable hearing rehabilitation with high score of word and sentence recognition. In this review, we will discuss different aspects of CS including clinical presentation, diagnosis, treatment, and future directives.

Retrospective cohort study on risk of hearing loss in patients with rheumatoid arthritis using claims data

OBJECTIVES

Population studies on hearing loss (HL) associated with rheumatoid arthritis (RA) are lacking. This study investigated the risk of developing HL in patients with RA using a nationwide population cohort.

SETTING

The population-based insurance claims data in the Taiwan National Health Insurance Research Database.

DESIGN

Retrospective cohort study followed up RA cohort and control cohort without RA frequency matched by sex, age and diagnosis year.

STUDY POPULATION

18 267 patients with RA newly diagnosed in 2000-2006 and 73 068 controls without RA.

MAIN OUTCOMES

Incidences of HL by the end of 2011 and the RA cohort to non-RA cohort HRs after adjusting for sex, age and comorbidities.

RESULTS

The HL incidence was higher in the RA cohort than in the non-RA cohort (3.08 vs 1.62 per 1000 person-years), with an adjusted HR (aHR) of 1.91 (95% CI 1.70 to 2.14) for the RA cohort relative to the non-RA cohort after controlling for age, sex and comorbidities. Men and the elderly are at a higher risk. Cardiovascular comorbidities were associated with a further increased HL risk for patients with RA. Medications were associated with reduced HL incidence; patients with RA who used non-steroidal anti-inflammatory drugs (NSAIDs) had an aHR of 0.12 (95% CI 0.07 to 0.20), compared with non-users.

CONCLUSIONS

This study demonstrates that patients with RA are at an increased risk of developing HL. Findings highlight the need of disease-modifying treatment and scheduled auditory examinations for HL prevention and early detection for patients with RA.