Autoimmunity as a candidate for the etiopathogenesis of Meniere's disease: detection of autoimmune reactions and diagnostic biomarker candidate

Ménière's disease and allergy: Epidemiology, pathogenesis, and therapy

The etiology of Ménière's disease (MD) remains controversial. Allergies are potential extrinsic factors that, in conjunction with underlying intrinsic factors, may cause MD. The link between allergies and MD was first described in 1923. For nearly a century, studies have demonstrated a possible link between allergies and MD, even though a causal relationship has not been definitively determined. Previous reviews have mainly focused on clinical epidemiology studies of patients. In this review, we shed light on the association between allergies and MD not only in terms of its epidemiology, but also from an immunology, pathophysiology, and immunotherapy perspective in both patients and animal models. Patients with MD tend to have a high risk of comorbid allergies or an allergy history, showing positive allergy immunology characteristics. Other MD-related diseases, such as migraine, may also interact with allergies. Allergy mediators such as IgE may worsen the symptoms of MD. Deposits of IgE in the vestibular end organs indicate the ability of the inner ear to participate in immune reactions. Allergic challenges can induce vertigo in animals and humans. Anti-allergy therapy plays a positive role in patients with MD and animal models of endolymphatic hydrops.

Immune-Related Disorders Associated With Ménière's Disease: A Systematic Review and Meta-analysis

OBJECTIVE

To analyze evidence supporting an association between immune-related diseases and Ménière's disease (MD) since it has long been thought to be related to autoimmune disorders and allergies.

DATA SOURCES

We retrieved records from Pubmed, Web of Science, Scopus, and Cochrane Library to identify studies published between January 2002 and October 2022.

REVIEW METHODS

Articles were independently assessed by 2 reviewers and verified by a third reviewer. Published cross-sectional studies, cohort/longitudinal studies, case series, and noncomparative cohort studies were considered eligible for inclusion. We conducted a systematic review and meta-analysis according to a registered protocol on the International Prospective Register of Systematic Reviews and Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Selected studies were classified into 2 groups: epidemiological and genetic association studies. Relative frequencies and odds ratios (ORs) for each autoinflammatory/autoimmune disease or genetic marker reported to be associated with MD.

RESULTS

Fifteen studies from 6 countries met our inclusion criteria. Nine are epidemiological studies and 6 are genetic association studies. The epidemiological studies were used to perform 3 different meta-analyses. Airway allergic disease and autoimmune thyroid disease showed a significant association with MD (OR = 2.27 [2.08-2.48] and OR = 1.35 [1.25-1.46]); while rheumatoid arthritis did not (OR = 0.63 [0.28-1.41]). Other comorbidities also showed a significant association with MD like chronic obstructive pulmonary disease, vitiligo, fibromyalgia, arthritis, and psoriasis.

CONCLUSION

Epidemiological evidence supports an association between MD and immune-related disorders in European and Asian populations, with population-specific effects. The evaluation of thyroid diseases, airway allergic diseases, and other inflammatory diseases should be implemented in the clinical management of MD patients.

Mass Spectrometric Interrogation of Earwax: Toward the Detection of Ménière's Disease

Many diseases remain difficult to identify because the occurrence of characteristic biomarkers within traditional matrices such as blood and urine remain unknown. Disease diagnosis could, therefore, benefit from the analysis of readily accessible, non-traditional matrices that have a high chemical content and contain distinguishing biomarkers. One such matrix is cerumen (i.e., earwax), whose chemical complexity can pose challenges when analyzed by conventional methods. A combination of cerumen chemical profiles analyzed by gas chromatography-mass spectrometry (GC-MS) and direct analysis in real time-high-resolution mass spectrometry (DART-HRMS) were investigated to ascertain the possible presence of the rare otolaryngological disorder Ménière's disease. This illness is currently identified via "diagnosis by exclusion" in which the disease is distinguished from others with overlapping symptoms by the process of elimination. GC-MS revealed a chemical profile difference between those with and without a Ménière's disease diagnosis by a visually apparent diminution of the compounds present in the Ménière's disease samples. DART-HRMS revealed that the two classes could be differentiated using three fatty acids: cis-9-hexadecenoic acid, cis-10-heptadecenoic acid, and cis-9-octadecenoic acid. These compounds were subsequently quantified by GC-MS and overall, the amounts of these fatty acids were decreased in Ménière's disease patients. The average levels for non-Ménière's disease samples were 7.89 μg/mg for cis-9-hexadecenoic acid, 0.87 μg/mg for cis-10-heptadecenoic acid, and 4.94 μg/mg for cis-9-octadecenoic acid. The average levels for Ménière's disease samples were 1.70 μg/mg for cis-9-hexadecenoic acid, 0.13 μg/mg for cis-10-heptadecenoic acid, and 2.07 μg/mg for cis-9-octadecenoic acid. The confidence levels for cis-9-hexadecenoic acid, cis-10-heptadecenoic acid, and cis-9-octadecenoic acid were 98.7%, 99.9%, and 95.4%, respectively. The results suggest that assessment of the concentrations of these fatty acids could be a useful clinical tool for the more rapid and accurate detection of Ménière's disease.

Thyroid Axis and Vestibular Physiopathology: From Animal Model to Pathology

A recent work of our group has shown the significant effects of thyroxine treatment on the restoration of postural balance function in a rodent model of acute peripheral vestibulopathy. Based on these findings, we attempt to shed light in this review on the interaction between the hypothalamic-pituitary-thyroid axis and the vestibular system in normal and pathological situations. Pubmed database and relevant websites were searched from inception through to 4 February 2023. All studies relevant to each subsection of this review have been included. After describing the role of thyroid hormones in the development of the inner ear, we investigated the possible link between the thyroid axis and the vestibular system in normal and pathological conditions. The mechanisms and cellular sites of action of thyroid hormones on animal models of vestibulopathy are postulated and therapeutic options are proposed. In view of their pleiotropic action, thyroid hormones represent a target of choice to promote vestibular compensation at different levels. However, very few studies have investigated the relationship between thyroid hormones and the vestibular system. It seems then important to more extensively investigate the link between the endocrine system and the vestibule in order to better understand the vestibular physiopathology and to find new therapeutic leads.

Untargeted Metabolomic Analysis in Endolymphatic Sac Luminal Fluid from Patients with Meniere's Disease

Dysfunction of the endolymphatic sac (ES) is one of the etiologies of Meniere's disease (MD), the mechanism of which remains unclear. The aim of the present study was to explore the molecular pathological characteristics of ES during the development of MD. Metabolomic profiling of ES luminal fluid from patients with MD and patients with acoustic neuroma (AN) was performed. Diluted ES luminal fluid (ELF) samples were obtained from 10 patients who underwent endolymphatic duct blockage for the treatment of intractable MD and from 6 patients who underwent translabyrinthine surgery for AN. ELF analysis was performed using liquid chromatography-mass spectrometry before the raw data were normalized and subjected to subsequent statistical analysis by MetaboAnalyst. Using thresholds of P ≤ 0.05 and variable important in projection > 1, a total of 111 differential metabolites were screened in the ELF, including 52 metabolites in negative mode and 59 in positive mode. Furthermore, 15 differentially altered metabolites corresponding to 15 compound names were identified using a Student's t-test, including 7 significant increased metabolites and 8 significant decreased metabolites. Moreover, two differentially altered metabolites, hyaluronic acid (HA) and 4-hydroxynonenal (4-HNE), were validated to be upregulated in the epithelial lining of the ES, as well as in the subepithelial connective-tissue in patients with MD comparing with that in patients with AN. Among these differentially altered metabolites, an upregulated expression of HA detected in the ES lumen of the patients with MD was supposed to be associated with the increased endolymph in ES, while an increased level of 4-HNE found in the ELF of the patients with MD provided direct evidence to support that oxidative damage and inflammatory lesions underlie the mechanism of MD. Furthermore, citrate and ethylenediaminetetraacetic acid were detected to be decreased substantially in the ELF of the patients with MD, suggesting the elevated endolymphatic Ca2+ in the ears with chronic endolymphatic hydrops is likely to be associated with the reduction of these two chelators of Ca2+ in ES. The results in the present study indicate metabolomic analysis in the ELF of the patients with MD can potentially improve our understanding on the molecular pathophysiological mechanism in the ES during the development of MD.

Vestibular migraine or Meniere's disease: a diagnostic dilemma

Meniere's disease (MD) represents one of the vertigo disorders characterized by triad symptoms (recurrent vertigo, fluctuating hearing loss, tinnitus or ear fullness). The diagnosis of MD relies on the accurate and detailed taking of medical history, and the differentiation between MD and vestibular migraine (VM) is of critical importance from the perspective of the treatment efficacy. VM is a highly prevalent vertigo condition and its typical symptoms (headache, vestibular symptoms, cochlear symptoms) mimic those of MD. Furthermore, the misdiagnosis in MD and VM could lead to VM patients mistakenly receiving the traumatic treatment protocol designed for MD, and sustaining unnecessary damage to the inner ear. Fortunately, thanks to the advances in examination technologies, the barriers to their differentiation are being gradually removed. These advances enhance the diagnostic accuracy of vertigo diseases, especially VM and MD. This review focused on the differentiation of VM and MD, with an attempt to synthesize existing data on the relevant battery of differentiation diagnosis (covering core symptoms, auxiliary tests [audiometry, vestibular tests, endolymphatic hydrops tests]) and longitudinal follow-up. Since the two illnesses are overlapped in all aspects, no single test is sufficiently specific on its own, however, patterns containing all or at least some features boost specificity.

Functional and Molecular Markers for Hearing Loss and Vertigo Attacks in Meniere's Disease

Meniere's disease (MD) is one of the most complicated diseases in the otologic clinic. The complexity of MD is partially due to the multifactorial etiological mechanisms and the heterogenous symptoms, including episodic vertigo, hearing loss, aural fullness and tinnitus. As a result, the diagnosis of MD and differentiating MD from other diseases with similar symptoms, such as vestibular migraine (VM), is challenging. In addition, it is difficult to predict the progression of hearing loss and the frequency of vertigo attacks. Detailed studies have revealed that functional markers, such as pure tone audiometry (PTA), electrocochleography (ECochG), vestibular evoked myogenic potential (VEMP), caloric test, video head impulse test (vHIT) and magnetic resonance imaging (MRI) could help to evaluate MD with different hearing levels and frequency of vertigo attacks. Investigations of molecular markers such as autoimmunity, inflammation, protein signatures, vasopressin and circadian clock genes in MD are still underway. This review will summarize these functional and molecular markers, address how these markers are associated with hearing loss and vertigo attacks in MD, and analyze the results of the markers between MD and VM.

Does Thyroid Hormone Metabolism Correlate with the Objective Assessment of the Vestibular Organ in Patients with Vertigo?

The aim of this study was to assess the relationship between the results of the objective assessment of the vestibular organ in patients with peripheral vertigo with Hashimoto's thyroiditis and thyroid hormone metabolism. Twenty eight women with Hashimoto's thyroiditis and chronic vertigo were enrolled in the study. Patients underwent audiological assessment of hearing, Dix-Hallpike test, videonystagmography with caloric test, head impulse test (HIT) and cervical vestibular-evoked myogenic potentials (cVEMPs). Levels of thyroid hormones and anti-thyroid antibodies were determined. Relationships between age, weight, height, BMI and the results of the objective assessment of the vestibular organ were calculated. The mean age in the study group was 48 years, while the mean BMI was 26.425. The causes of peripheral vertigo in the study group were benign paroxysmal positional vertigo (BPPV) (n = 19), Meniere's disease (n = 7) and vestibular neuronitis (n = 2). No correlation was found between age, weight, height, BMI and the results of thyroid function tests or the objective assessment of the vestibular organ. The study did not confirm the influence of thyroid metabolism (i.e., thyroid hormone levels or the increase in antithyroid antibodies) on the results of cVEMP or the directional preponderance in the caloric test.

Potential nanotechnology-based diagnostic and therapeutic approaches for Meniere's disease

Meniere's disease (MD) is a progressive inner ear disorder involving recurrent and prolonged episodes or attacks of vertigo with associated symptoms, resulting in a significantly reduced quality of life for sufferers. In most cases, MD starts in one ear; however, in one-third of patients, the disorder progresses to the other ear. Unfortunately, the etiology of the disease is unknown, making the development of effective treatments difficult. Nanomaterials, including nanoparticles (NPs) and nanocarriers, offer an array of novel diagnostic and therapeutic applications related to MD. NPs have specific features such as biocompatibility, biochemical stability, targetability, and enhanced visualization using imaging tools. This paper provides a comprehensive and critical review of recent advancements in nanotechnology-based diagnostic and therapeutic approaches for MD. Furthermore, the crucial challenges adversely affecting the use of nanoparticles to treat middle ear disorders are investigated. Finally, this paper provides recommendations and future directions for improving the performances of nanomaterials on theragnostic applications of MD.

Elevated G-CSF, IL8, and HGF in patients with definite Meniere's disease may indicate the role of NET formation in triggering autoimmunity and autoinflammation

The etiology and mechanism causing Meniere’s disease (MD) are not understood. The present study investigated the possible molecular mechanism of autoimmunity and autoinflammation associated with MD. Thirty-eight patients with definite MD and 39 normal volunteers were recruited, and 48 human cytokines/chemokines were quantified. In patients with MD pure tone audiograms, tympanograms and standard blood tests were performed. The mean hearing loss in the worse ear was 44.1 dB nHL. Compared to the referents, the concentrations of TNFα, IL1α, IL8, CTACK, MIP1α, MIP1β, G-CSF, and HGF in the sera of patients with MD were significantly elevated, while those of TRAIL and PDGFBB were significantly decreased. The area under the receiver operating characteristic curve (AUC) showed that G-CSF, MIP1α, and IL8 were above 0.8 and could be used to diagnose MD (p < 0.01), and the AUCs of CTACK and HGF were above 0.7 and acceptable to discriminate the MD group from the control group (p < 0.01). The revised AUCs (1 − AUC) of TRAIL and PDGFBB were above 0.7 and could also be used in the diagnosis of MD (p < 0.01). The linear regression showed significant correlations between MIP1α and GCSF, between IL2Rα and GCSF, between IL8 and HGF, between MIP1α and IL8, and between SCF and CTACK; there was a marginal linear association between IP10 and MIP1α. Linear regression also showed that there were significant age-related correlations of CTACK and MIG expression in the MD group (p < 0.01, ANOVA) but not in the control group. We hypothesize that G-CSF, IL8, and HGF, which are involved in the development of neutrophil extracellular traps (NETs) and through various mechanisms influence the functions of macrophages, lymphocytes, and dendritic cells, among others, are key players in the development of EH and MD and could be useful in elucidating the pathophysiological mechanisms leading to MD. Biomarkers identified in the present study may suggest that both autoimmune and autoinflammatory mechanisms are involved in MD. In the future, it will be valuable to develop a cost-effective method to detect G-CSF, IL8, HGF, CTACK, MIP1α, TRAIL, and PDGFBB in the serum of patient that have diagnostic relevance.

Transcriptional Down-Regulation of Major Histocompatibility Complex as a Possible Pathogenesis for Meniere's Disease

Objectives

This study aimed to determine the underlying pathogenesis of Meniere's disease (MD) using transcriptome analysis.

Methods

Total RNA was extracted from the peripheral blood mononuclear cells of 39 patients with MD and 39 controls. Through microarray analysis for nine patients and controls, the differentially expressed genes (DEGs) of those two groups were screened based on cut-off criteria (|fold changes| > 2.0 and adjusted p-value < 0.05). The functional enrichment analysis of DEGs was performed using Gene Ontology (GO).

Results

There were 996 DEGs identified in the MD group: 415 were upregulated and 581 were downregulated. A functional enrichment analysis indicated that the downregulated DEGs were significantly enriched in terms related to immune system processes. Among them, 17 genes were enriched in terms for the major histocompatibility complex (MHC) protein complex, and the relative messenger RNA (mRNA) levels of three markedly downregulated DEGs [fold changes < −5: human leukocyte antigen (HLA)-DMA, HLA-DRB1, and HLA-DPB1] were significantly decreased in another 30 patients with MD compared with normal controls by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). However, there were no correlations between the expression levels of these three genes and clinical data, such as age, onset age, time course, or hearing threshold.

Conclusions

Our transcriptome analysis showed that the downregulated DEGs in MD were mainly associated with the immune system pathways including the MHC protein complex in MD. Remarkably, a breakdown in immunological tolerance mediated by MHC class II may contribute to the MD development, which has implications for targeted treatment.

Duration of symptom control following intratympanic dexamethasone injections in Meniere’s disease

Purpose

Intratympanic (IT) injections of corticosteroids have emerged as a non-ablative alternative to gentamicin in the management of refractory Meniere’s disease. However, currently, the duration of the symptom control achieved via intratympanic corticosteroids is under reported.

Methods

We retrospectively reviewed the notes of all patients who underwent IT injections of dexamethasone for the treatment of definite Meniere’s disease at a single tertiary referral university centre over a 6-year period. We included demographic information, the number of procedures patients required, duration of symptom-control achieved (time interval between repeat IT injections), and the presence of co-morbidities, with a focus on the presence of autoimmune disease.

Results

We identified 27 patients who underwent a total of 42 procedures; 23/27 (85.2%) patients demonstrated clinical response with a median period of symptom control of 14.5 months (range 1–64, IQR 10.25). The median longest asymptomatic period per patient was 19 months (range 11–64, IQR: 18). Interestingly, all patients with autoimmune disease (7/27) demonstrated a clinical response; autoimmune disease was found to be a statistically significant predictor of response to treatment (p = 0.002). In patients who received repeated treatment following disease relapse, there was no difference in duration of symptom-control achieved.

Conclusions

IT steroids can provide an effective alternative to gentamicin ablation. Symptom control is achieved for a median of 14.5 months, and treatment can be repeated with no loss of efficacy. Those patients who have an underlying autoimmune co-morbidity are more likely to demonstrate a clinical response to therapy, which may provide insight into the underlying pathophysiology of Meniere’s disease.

Up-Regulated Expression of Interferon-Gamma, Interleukin-6 and Tumor Necrosis Factor-Alpha in the Endolymphatic Sac of Meniere's Disease Suggesting the Local Inflammatory Response Underlies the Mechanism of This Disease

Background

Immune mediated inflammatory changes affecting the endolymphatic sac (ES) may underlie the pathology of Meniere's disease (MD). The aim of the present study was to explore the differentially expressed cytokines in ES luminal fluid (ELF) of patients with MD, and the correlation between the expression of cytokines in the ELF with that in the serum was determined by quantitatively analyzing the cytokines in human ELF and serum.

Methods

Human ELF, serum and ES tissues were collected from patients with unilateral MD and patients with acoustic neuroma (AN) during surgery. The Simoa Cytokine 6-Plex Panel kit was used to analyze the levels of cytokines in the ELF and blood samples of the patients. Immunohistochemistry and immunofluorescence were subsequently used to validate the relative expression levels of the cytokines in MD.

Results

Significant differences were identified in the expression levels of interferon-γ (IFN-γ) (P < 0.001), interleukin (IL)-6 (P = 0.008) and tumor necrosis factor-α (TNF-α) (P = 0.036) in the luminal fluid of the ES comparing between the MD and AN groups. By contrast, the levels of IFN-γ, IL-10, IL-12p70, IL-17A, IL-6 and TNF-α in the serum of the MD group were not significantly different from those of either the AN group or healthy control subjects. In addition, no significant correlations in the expression levels of cytokines compared between the ELF and serum were found for the patients in either the MD or the AN group. Finally, the detection of positive expression of TNF-α, IL-6 and IFN-γ in the epithelial cells of the majority of ES specimens from patients with MD confirmed the up-regulated expression of these cytokines in the ES of patients with MD.

Conclusions

The identification of up-regulated expression levels of TNF-α, IL-6 and IFN-γ in the ELF in the present study has provided direct evidence for an increased immunologic activity in the microenvironment of the ES in patients with unilateral MD, may suggest the local inflammatory response underlies the mechanism of this disease.

Bidirectional Transport of IgE by CD23 in the Inner Ear of Patients with Meniere's Disease

Meniere's disease (MD) is a disorder of the inner ear characterized by episodes of spontaneous vertigo, fluctuating hearing loss, and tinnitus. Recent studies have demonstrated that IgE may play a role in the pathogenesis of MD. Patients with MD (n = 103), acoustic neuroma (n = 5), and healthy subjects (n = 72) were recruited into the study. Serum from the participants was analyzed for IgE and type 2-related cytokines. IgE and CD23 expression levels in vestibular end organs of patients, C57BL/6 mice, or mouse HEI-OC1 cells were analyzed. Finally, the role of CD23 in IgE transcytosis was assessed using HEI-OC1 cells. Serum IgE was elevated in patients with MD and positively correlated with clinical symptoms. IL-4, IL-5, IL-10, IL-13, and CD23 levels were increased in patients with MD compared with the control group. In the transcytosis assay, mouse IgE was found to be bidirectionally transported across the HEI-OC1 cell monolayer. Additionally, CD23 downregulation using a small interfering RNA approach significantly reduced the efficiency of IgE transcytosis, suggesting that IgE is transported by CD23. Furthermore, exposure to IL-4 increased CD23 expression and enhanced IgE transcytosis in the HEI-OC1 cells and primary vestibular end organs. Our study indicated that IgE may play a role in the pathophysiology of MD. In addition, CD23-mediated IgE transcytosis in the hair cells may play a critical role in initiating inflammation in the inner ear. Thus, reducing the level of IgE may be a potentially effective approach for MD treatment.

Cytokines and Inflammation in Meniere Disease

Meniere disease (MD) is a rare set of conditions associated with the accumulation of endolymph in the cochlear duct and the vestibular labyrinth with a decrease of endocochlear potential. It is considered a chronic inflammatory disorder of the inner ear with a multifactorial origin. The clinical syndrome includes several groups of patients with a core phenotype: sensorineural hearing loss, episodes of vertigo, and tinnitus with a non-predictable course. Genetic factors and the innate immune response seem to play a central role in the pathophysiology of the condition. Autoimmune MD should be diagnosed if a patient fulfills the diagnostic criteria for MD and one of the following autoimmune disorders: autoimmune thyroid disease, psoriasis, autoimmune arthritis, ankylosing spondylitis, or systemic lupus erythematosus. We summarize the evidence to support autoimmune MD as an endophenotype in bilateral MD associated with the allelic variant rs4947296 and nuclear factor-kappa B (NF-κB)-mediated inflammation, the role of cytokines (particularly interleukin-1β and tumor necrosis factor-α) in defining a subset of patients with autoinflammation, and the potential role of cytokines as biomarkers to distinguish between patients with MD and vestibular migraine. Finally, we also introduce a list of potential drugs that could regulate the immune response in MD with potential for repurposing in clinical trials.

The Prevalence of Autoimmune Diseases in Patients with Primary Open-Angle Glaucoma Undergoing Ophthalmic Surgeries

PURPOSE

To assess the prevalence of autoimmune disease (AiD) in patients with primary open-angle glaucoma (POAG) undergoing ophthalmic surgery.

DESIGN

Retrospective, cross-sectional study.

PARTICIPANTS

Patients with POAG undergoing any ophthalmic surgery and control subjects undergoing cataract surgery at the Massachusetts Eye and Ear from March 2019 to April 2020.

METHODS

All available medical records with patient demographics, ocular, and medical conditions were reviewed. Differences in AiD prevalence were assessed and adjusted for covariates using multiple logistic regression. Additionally, a subgroup analysis comparing the POAG patients with and without AiD was performed.

MAIN OUTCOME MEASURES

To assess the prevalence of AiD based on the American Autoimmune Related Diseases Association list.

RESULTS

A total of 172 patients with POAG and 179 controls were included. The overall prevalence of AiD was 17.4% in the POAG group and 10.1% in the controls (P = 0.044); 6.4% of POAG patients and 3.4% of controls had more than 1 AiD (P = 0.18). The most prevalent AiDs in POAG group were rheumatoid arthritis (4.6%) and psoriasis (4.1%), which were also the most common in controls (2.8% each). In a fully adjusted multiple logistic regression analysis accounting for steroid use, having an AiD was associated with 2.62-fold increased odds of POAG relative to controls (95% confidence interval, 1.27-5.36, P = 0.009); other risk factors for POAG derived from the analysis included age (odds ratio [OR], 1.04, P = 0.006), diabetes mellitus (OR, 2.31, P = 0.008), and non-White ethnicity (OR, 4.75, P < 0.001). In a case-only analysis involving the eye with worse glaucoma, there was no statistical difference in visual field mean deviation or retinal nerve fiber layer (RNFL) thickness in POAG patients with AiD (n = 30) and without AiD (n = 142, P > 0.13, for both).

CONCLUSIONS

A higher prevalence of AiD was found in POAG patients compared with control patients undergoing ophthalmic surgery. The presence of AiD was associated with increased risk for POAG after adjusting for covariates. Additional factors may have prevented a difference in RNFL thickness in POAG patients with and without AiD. Autoimmunity should be explored further in the pathogenesis of POAG.

A finite element model to predict the consequences of endolymphatic hydrops in the basilar membrane

Ménière's disease is an inner ear disorder, associated with episodes of vertigo, fluctuant hearing loss, tinnitus, and aural fullness. Ménière's disease is associated with endolymphatic hydrops. Clinical evidences show that this disease is often incapacitating, negatively affecting the patients' everyday life. The pathogenesis of Ménière's disease is still not fully understood and remains unclear. Previous numerical studies available in the literature related with endolymphatic hydrops, are very scarce. The present work applies the finite element method to investigate the consequences of endolymphatic hydrops in the normal hearing, associated with the Ménière's disease. The obtained results for the steady state dynamics analysis are in accordance with clinical evidences. The results show that the basilar membrane is not affected in the same intensity along its length and that the lower frequencies are more affected by the endolymphatic hydrops. From a clinical point of view, this work shows the relationship between the increasing of the endolymphatic pressure and the development of hearing loss.

Cyclophosphamide inhibits the progression of Meniere's disease by reducing the generation of circulating immune complex

Endolymphatic hydrops is a characteristic pathological manifestation of Meniere's disease (MD) that has been previously associated with autoimmunity. Interest in the circulating immune complex (CIC) has increased due to its reported role in the occurrence of MD. The present study aimed to investigate the potential value of serum CIC concentration in the diagnosis of MD and the therapeutic potential of cyclophosphamide (CTX) for the treatment of MD. In the present study, guinea pigs were immunized with isologous crude inner ear antigens to establish an autoimmune MD model. Pure tone audiometry, Vestibular-evoked myogenic potential test, electrocochleography test and auditory brainstem response was applied in this study for assessing the severity of MD in guinea pigs. ELISA was applied to measure CIC, tumor necrosis factor α (TNF-α) and heat shock protein 70 (HSP70) expression levels in the serum samples of different groups of patients. Western blotting was applied to detect the protein expression of HSP70 in inner ear tissues in guinea pigs. Hematoxylin and eosin staining was applied to visualize the spiral ganglions in spiral ganglions models. CIC expression in the inner ear was detected by immunohistochemistry. In vivo experiments were performed to confirm the therapeutic effects of CTX in MD. Serum concentrations of CIC, TNF-α and HSP70 were found to be significantly higher in patients with MD, which were also associated with increases in hearing classification and the severity of endolymphatic hydrops. Using a guinea pig MD model, ELISA results revealed significantly increased serum CIC, TNF-α and HSP70 concentrations compared with those in the control group. ABR results showed that the thresholds in the CTX group were notably decreased compared with that in the dexamethasone group, whereas CIC concentrations in the serum were reduced following dexamethasone and CTX treatments compared with those after saline treatment. In the inner ear tissues, the CIC concentration in CTX group was lower than that in the dexamethasone group. Similarly, reductions in HSP70 and TNF-α concentrations was also observed in a similar manner. Immunohistochemistry staining found notably lower CIC deposition in the inner ear tissues following CTX treatment than that in dexamethasone group. Taken together, higher CIC expression can be used as a biomarker for MD diagnosis. The efficacy of CTX in MD was found to be higher compared with that in dexamethasone, which may be associated with the effective inhibition of CIC, HSP70 and TNF-α generation.

Evaluation of a large cohort of adult patients with Ménière's disease: bedside and clinical history

Objective

The purpose of this study was to assess vestibular findings and clinical history in a large cohort of patients affected by Ménière’s disease.

Methods

We retrospectively analysed 511 adult patients fulfilling criteria for definite unilateral Ménière’s disease according to Barany Society. Thorough clinical history, audiometric exam, central nervous system MRI, quantification of serum autoantibodies and complete vestibular function test were performed.

Results

Mean age at clinical record was 55.4 years, while age at onset of the first vertigo attack was 47.4 ± 14.3 years. Ménière’s disease overlapped with migraine in 43.4% of patients. In 31.7% of cases, positivity was found for at least one autoantibody. Forty-nine patients (9.6%) had family history for Ménière’s disease. Bedside examination resulted in 14.7% positivity for video head impulse test, 58.9% for skull vibration-induced nystagmus, 38.7% for the positional test and 23.1% for the post head shaking test. Complete negative examination was reported in 115 cases.

Conclusions

Ménière’s disease was seen to present a characteristic phenotypic pattern in our cohort, confirming the crucial role of thorough anamnesis and bedside examination in diagnosis.

Distinct MicroRNA Profiles in the Perilymph and Serum of Patients With Menière's Disease

Hypothesis: Menière's disease microRNA (miRNA) profiles are unique and are reflected in the perilymph and serum of patients.

Background: Development of effective biomarkers for Menière's disease are needed. miRNAs are small RNA sequences that downregulate mRNA translation and play a significant role in a variety of disease states, ultimately making them a promising biomarker. miRNAs can be readily isolated from human inner ear perilymph and serum, and may exhibit disease-specific profiles.

Methods: Perilymph sampling was performed in 10 patients undergoing surgery; 5 patients with Meniere's disease and 5 patients with otosclerosis serving as controls. miRNAs were isolated from the serum of 5 patients with bilateral Menière's disease and compared to 5 healthy age-matched controls. For evaluation of miRNAs an Agilent miRNA gene chip was used. Analysis of miRNA expression was carried out using Qlucore and Ingenuitey Pathway Analysis software. Promising miRNAs biomarkers were validated using qPCR.

Results: In the perilymph of patients with Menière's disease, we identified 16 differentially expressed miRNAs that are predicted to regulate over 220 different cochlear genes. Six miRNAs are postulated to regulate aquaporin expression and twelve miRNAs are postulated to regulate a variety of inflammatory and autoimmune pathways. When comparing perilymph with serum samples, miRNA-1299 and−1270 were differentially expressed in both the perilymph and serum of Ménière's patients compared to controls. Further analysis using qPCR confirmed miRNA-1299 is downregulated over 3-fold in Meniere's disease serum samples compared to controls.

Conclusions: Patients with Ménière's disease exhibit distinct miRNA expression profiles within both the perilymph and serum. The altered perilymph miRNAs identified can be linked to postulated Ménière's disease pathways and may serve as biomarkers. miRNA-1299 was validated to be downregulated in both the serum and perilymph of Menière's patients.

Applications of Protein Microarrays in Biomarker Discovery for Autoimmune Diseases

Dysregulated autoantibodies and cytokines were deemed to provide important cues for potential illnesses, such as various carcinomas and autoimmune diseases. Increasing biotechnological approaches have been applied to screen and identify the specific alterations of these biomolecules as distinctive biomarkers in diseases, especially autoimmune diseases. As a versatile and robust platform, protein microarray technology allows researchers to easily profile dysregulated autoantibodies and cytokines associated with autoimmune diseases using various biological specimens, mainly serum samples. Here, we summarize the applications of protein microarrays in biomarker discovery for autoimmune diseases. In addition, the key issues in the process of using this approach are presented for improving future studies.

Association Between Serum Vitamin D Level and Ménière's Disease

OBJECTIVES

Ménière's disease (MD) is a well-known inner ear disease; however, the etiopathogenesis is unknown. Several factors may be involved. Meanwhile, vitamin D is reported to have an important role in inner ear physiology. The aim of this study is to evaluate the relation between vitamin D deficiency and MD.

STUDY DESIGN

This matched case-control study compared serum vitamin D levels between patients with definite MD and those without it.

SETTING

The study was done between August 2018 and December 2019 at Ghaem University Hospital in Mashhad, Iran.

METHODS

Twenty-eight patients with definite MD were matched with a group of 84 healthy individuals, regarding age, sex, body mass index, and occupation (indoor vs outdoor). The serum level of vitamin D (25-hydroxyvitamin D3) was measured in both groups.

RESULTS

The mean ± SD vitamin D level was 18.9 ± 9.7 ng/mL in the case group and 25.2 ± 13.7 ng/mL in the control group (P = .027). There was a significant difference between the case and control groups according to the results of the conditional logistic regression model (P = .03; adjusted odds ratio, 0.96). In the MD group, 17 (60.7%) patients were vitamin D deficient, 6 (21.4%) insufficient, and only 5 (17.9%) sufficient.

CONCLUSIONS

The results of this study show that serum vitamin D level in MD is significantly lower than that of the control group. However, the role of vitamin D supplementation in the management of MD needs further study.

LEVEL OF EVIDENCE

4.

The transcriptome characteristics of vestibular organs from delayed endolymphatic hydrops patients (Meniere's disease)

OBJECTIVES

To identify genes that are related to delayed endolymphatic hydrops (DEH) in patients by RNA-Seq analysis.

DESIGN

Observational study.

SETTING

Eye & ENT Hospital, Fudan University (Shanghai, China).

PARTICIPANTS

We collected the entire vestibular system from four patients with DEH who underwent labyrinthectomy. Three control samples were collected from patients with acoustic neuroma or facial neuroma treated via the translabyrinthine approach. High-throughput RNA-Seq analysis was performed to investigate gene expression in the pathological vestibular system.

MAIN OUTCOME MEASURES

Our bioinformatic analysis identified 17 genes that were upregulated and eight genes that were downregulated in patients with DEH compared with the controls.

RESULTS

The altered gene expression profile suggested that DEH is closely related to neuropathy and autoimmune disease. In addition, many of the differentially regulated genes were involved in cell adhesion, suggesting a role of cell adhesion in DEH. Immunofluorescence analysis confirmed the expression of PMP2 and CLDN19 in the cytoplasm of hair cells and scattered expression of MPZ at cell junctions. The protein expression levels were higher in specimens from patients with Ménière's disease and DEH compared with controls.

CONCLUSIONS

The protein expression profile of vestibular organs in patients with endolymphatic hydrops exhibited a degree of similarity to that of Ménière's disease. Endolymphatic hydrops is characterised by autoimmune abnormalities. DEH and Ménière's disease are likely to be different manifestations of the same disease, with disparate clinical symptoms. RNA-Seq is a useful analytical tool to characterise the vestibular pathology based on its transcriptome.

Biomarkers for Inner Ear Disorders: Scoping Review on the Role of Biomarkers in Hearing and Balance Disorders

The diagnostics of inner ear diseases are primarily functional, but there is a growing interest in inner ear biomarkers. The present scoping review aimed to elucidate gaps in the literature regarding the definition, classification system, and an overview of the potential uses of inner ear biomarkers. Relevant biomarkers were categorized, and their possible benefits were evaluated. The databases OVID Medline, EMBASE, EBSCO COINAHL, CA PLUS, WOS BIOSIS, WOS Core Collection, Proquest Dissertations, Theses Global, PROSPERO, Cochrane Library, and BASE were searched using the keywords “biomarker” and “inner ear”. Of the initially identified 1502 studies, 34 met the inclusion criteria. The identified biomarkers were classified into diagnostic, prognostic, therapeutic, and pathognomonic; many were detected only in the inner ear or temporal bone. The inner-ear-specific biomarkers detected in peripheral blood included otolin-1, prestin, and matrilin-1. Various serum antibodies correlated with inner ear diseases (e.g., anti-type II collagen, antinuclear antibodies, antibodies against cytomegalovirus). Further studies are advised to elucidate the clinical significance and diagnostic or prognostic usage of peripheral biomarkers for inner ear disorders, filling in the literature gaps with biomarkers pertinent to the otology clinical practice and integrating functional and molecular biomarkers. These may be the building blocks toward a well-structured guideline for diagnosing and managing some audio-vestibular disorders.

Developments and Applications of Functional Protein Microarrays

Protein microarrays are crucial tools in the study of proteins in an unbiased, high-throughput manner, as they allow for characterization of up to thousands of individually purified proteins in parallel. The adaptability of this technology has enabled its use in a wide variety of applications, including the study of proteome-wide molecular interactions, analysis of post-translational modifications, identification of novel drug targets, and examination of pathogen-host interactions. In addition, the technology has also been shown to be useful in profiling antibody specificity, as well as in the discovery of novel biomarkers, especially for autoimmune diseases and cancers. In this review, we will summarize the developments that have been made in protein microarray technology in both in basic and translational research over the past decade. We will also introduce a novel membrane protein array, the GPCR-VirD array, and discuss the future directions of functional protein microarrays.

Bidirectional analysis of the association between Ménière's disease and depression: Two longitudinal follow-up studies using a national sample cohort

OBJECTIVE

This study aimed to delineate the causal relationship between Ménière's disease and depression.

DESIGN

Two longitudinal follow-up studies.

MAIN OUTCOME MEASURES

The 2002-2013 Korean National Health Insurance Service-Health Screening Cohort was used. In study I, Ménière's disease patients were 1:4 matched with the control I group for age group, sex, income group and region of residence, and the occurrence of depression was observed. In study II, the depression patients were 1:4 matched with the control II group for the same variables, and the occurrence of Ménière's disease was observed. The stratified Cox proportional hazard model was used. Subgroup analyses were performed according to age and sex.

RESULTS

In study I, 6.9% (420/6044) of the Ménière's disease patients and 3.7% (885/24 176) of the control I participants experienced depression. The adjusted hazard ratio (HR) of Ménière's disease for depression was 1.94 (95% confidence intervals [CI] = 1.73-2.18, P < .001). In study II, 1.6% (490/31 649) of the depression patients and 1.0% (1240/126 596) of the control II participants were diagnosed with Ménière's disease. The adjusted HR of depression for Ménière's disease was 1.58 (95% CI = 1.43-1.76, P < .001). All age and sex subgroups demonstrated higher HRs of Ménière's disease for depression (study I) and depression for Ménière's disease (study II).

CONCLUSION

Ménière's disease patients showed an increased likelihood of depression. Conversely, depression patients showed an elevated likelihood of Ménière's disease.

Limbic System Associated Membrane Protein Mutation in an Iranian Family Diagnosed with Ménière's Disease

BACKGROUND

Ménière's disease (MD) is a common inner ear disorder which is characterized by recurrent attacks of vertigo, fluctuating sensorineural hearing loss (SNHL), tinnitus, and a sense of fullness in the affected ear. MD is a complex disorder; although six genes have been linked to familial autosomal dominant form of the disease, in many cases, the exact genetic etiology remains elusive.

METHODS

To elucidate the genetic causes of MD in an Iranian family, we performed exome sequencing on all members of the family: consanguineous parents and four children (two affected and two unaffected). Variant filtering was completed using a customized workflow keeping variants based on segregation with MD in autosomal recessive (AR) inheritance pattern, minor allele frequency (MAF), and in-silico prediction of pathogenicity.

RESULTS

Analysis revealed that in this family, 970 variants co-segregated with MD in AR pattern, out of which eight variants (one intergenic, four intronic, and three exonic) were extremely rare. The exonic variants included a synonymous substitution in USP3 gene, an in-frame deletion in ZBED2 gene, and a rare, highly conserved deleterious missense alteration in LSAMP gene.

CONCLUSION

The phenotype observed in the proband described here, i.e. vertigo, poor sense of smell, tinnitus, and borderline hearing ability, may originate from aberrant changes in the cerebellum and limbic system due to a deleterious mutation in the LSAMP gene; hence, LSAMP mutation is a possible candidate for the etiology of MD in this family.

Rare Variants of Putative Candidate Genes Associated With Sporadic Meniere's Disease in East Asian Population

Objectives: The cause of Meniere's disease (MD) is unclear but likely involves genetic and environmental factors. The aim of this study was to investigate the genetic basis underlying MD by screening putative candidate genes for MD.

Methods: Sixty-eight patients who met the diagnostic criteria for MD of the Barany Society were included. We performed targeted gene sequencing using next generation sequencing (NGS) panel composed of 45 MD-associated genes. We identified the rare variants causing non-synonymous amino acid changes, stop codons, and insertions/deletions in the coding regions, and excluded the common variants with minor allele frequency >0.01 in public databases. The pathogenicity of the identified variants was analyzed by various predictive tools and protein structural modeling.

Results: The average read depth for the targeted regions was 1446.3-fold, and 99.4% of the targeted regions were covered by 20 or more reads, achieving the high quality of the sequencing. After variant filtering, annotation, and interpretation, we identified a total of 15 rare heterozygous variants in 12 (17.6%) sporadic patients. Among them, four variants were detected in familial MD genes (DTNA, FAM136A, DPT), and the remaining 11 in MD-associated genes (PTPN22, NFKB1, CXCL10, TLR2, MTHFR, SLC44A2, NOS3, NOTCH2). Three patients had the variants in two or more genes. All variants were not detected in our healthy controls (n = 100). No significant differences were observed between patients with and without a genetic variant in terms of sex, mean age of onset, bilaterality, the type of MD, and hearing threshold at diagnosis.

Conclusions: Our study identified rare variants of putative candidate genes in some of MD patients. The genes were related to the formation of inner ear structures, the immune-associated process, or systemic hemostasis derangement, suggesting the multiple genetic predispositions in the development of MD.

Is Early Progression to Bilateral Involvement in Menière's Disease a Poor Prognostic Indicator?

OBJECTIVE

To investigate differences in the clinical features of bilateral Menière's disease (BMD) with early and late bilateral involvement.

STUDY DESIGN

A retrospective case-comparison study.

SETTING

Tertiary referral center.

PATIENTS

In total, 25 patients with definite BMD were enrolled. Patients with bilateral involvement with a transition interval shorter than 1 month were considered to have synchronous BMD, whereas the others had metachronous BMD.

INTERVENTIONS

We investigated differences in prognosis as defined by changes in the number of vertigo attacks after treatment, demographics, comorbidities, and inner ear function according to the transition interval from unilateral to bilateral involvement.

MAIN OUTCOME MEASURE

We investigated other appropriate cut-off values in the interval from first- to second-ear involvement to predict poor prognosis.

RESULTS

Receiver operating characteristic curve analysis revealed that a cut-off value of < 18-month interval exhibited maximum sensitivity and specificity for predicting poor prognosis. According to this value, we categorized patients into the early bilateral involvement group (EBIG, < 18 months' interval) and the late bilateral involvement group (LBIG, ≥ 18 months' interval). Patients with synchronous BMD and patients in the EBIG group exhibited poorer prognosis compared with patients with metachronous BMD and those in LBIG (p = 0.011 and p ≤ 0.001). Demographics, hearing threshold, vestibular deficit, and comorbidities were not significantly different between the two groups (p > 0.05). None of the patients exhibited systemic autoimmune disease.

CONCLUSION

BMD with early bilateral progression exhibited poorer prognosis compared with late bilateral progression.

Autoimmune vertigo: an update on vestibular disorders associated with autoimmune mechanisms

The role of the immune system in mediating cochleovestibular pathologies has received increasing attention in recent years. Autoimmune vertigo may be an invalidating condition and may worsen the quality of life of affected patients, especially in the cases of delayed diagnosis. Since the etiopathogenesis is still not clear, also the treatment is not yet completely delineated. According to the clinical presentation, autoimmune vertigo can present as an isolated disorder or in association with systemic autoimmune diseases. The main feature in autoimmune vertigo is the presence of an abnormal immune response, in either absence or presence of systemic autoimmune disease, directed against delicate components of the inner ear. This may determine a functional or anatomical alteration, with an inflammatory reaction often devastating for hearing and balance. Being the exact pathogenesis unknown, the diagnosis of autoimmune vertigo is based either on clinical criteria or on a positive response to steroids. The earlier the diagnosis is made, the sooner the therapy can be installed, giving a chance to the recovery of inner ear damages. Corticosteroids represent the most effective and universally accepted treatment, even if other immunomodulatory drugs are now having a more extensive use. HIGHLIGHTS: Vertigo is relatively frequent in autoimmune diseases; however, it is often misdiagnosed or attributed to central nervous system alterations rather to specific inner ear involvement. Vertigo and other audiovestibular symptoms may be the first manifestation of an autoimmune disease and if correctly addressed could significantly contribute to early diagnosis of the underlying autoimmune disease. Early diagnosis of immune-related vertigo can lead to prompt initiation of targeted therapy with elevate chances of preventing irreversible damages to the inner ear. The presence of alternating phases of well-being and disabling symptoms in patients with vertigo should always been considered, as they could suggest an underlying autoimmune condition.

Pathophysiologic Findings in the Human Endolymphatic Sac in Endolymphatic Hydrops: Functional and Molecular Evidence

BACKGROUND

The endolymphatic sac (ES) is a cystic structure situated on the posterior fossa dura and is connected to the luminal space of the vestibular organ through the endolymphatic duct, which branches into the utricular and saccular ducts. Unlike the cochlea and vestibule, the ES does not contain sensory epithelium in its luminal space, and a single layer of epithelial cells line the luminal surface area. The ES in the inner ear is thought to play a role in the regulation of inner ear homeostasis, fluid volume, and immune reaction. If these functions of the ES are disrupted, dysfunction of the inner ear may develop. The most well-known pathology arising from dysfunction of the ES is endolymphatic hydrops, characterized by an enlarged endolymphatic space due to the accumulation of excessive endolymphatic fluid. Although, molecular identities and functional evidence for the roles were identified in animal studies, basic studies of the human ES are relatively uncommon compared with those using animal tissues, because of limited opportunity to harvest the human ES.

METHODS

In this study, molecular and functional evidence for the role of the human ES in the development of endolymphatic hydrops are reviewed.

RESULTS AND CONCLUSIONS

Although evidence is insufficient, studies using the human ES have mostly produced findings similar to those of animal studies. This review may provide a basis for planning further studies to investigate the pathophysiology of disorders with the finding of endolymphatic hydrops.

Histamine H4 receptor gene polymorphisms: a potential contributor to Meniere disease

BACKGROUND

The immune system is likely involved in the pathophysiology of Meniere's disease (MD). However, its role of patients with MD has not been well studied. Given that histamine H4 receptors are highly expressed in immune system, we tested the hypothesis that histamine H4 receptor gene polymorphisms are a potential contributor to the risk of MD.

METHODS

A group of patients was enrolled with a diagnosis of definite MD based on the American Academy of Otolaryngology-Head and Neck Surgery Committee on Hearing and Equilibrium guidelines and a control group of patients without any vestibular disease. We selected one SNP, rs77485247 in HRH4 and conducted an exploratory investigation of its correlations with the symptoms of vertigo and proinflammatory cytokines levels in MD patients.

RESULTS

HRH4 rs77485247 polymorphism may be associated with the risk of MD. Furthermore, basal levels of proinflammatory cytokines, such as IL-1β and TNF-α, in PBMCs are increased in patients with MD compared to control patients. This increased basal level of proinflammatory cytokines is prominent in MD patients with the A allele.

CONCLUSIONS

These suggested that HRH4 rs77485247 polymorphism may be an important mediator in regulating proinflammatory cytokines, which are involved in the pathogenesis of MD.

Hypothyroidism is an independent risk factor for Menière's disease: A population-based cohort study

The relationship of hypothyroidism and Menière's disease (MD) has been discussed before, yet not well documented. Our study aims to investigate the correlation of both diseases.This is a retrospective cohort study based on data from the LHID2000 (Longitudinal Health Insurance Database 2000), a subset of the Taiwan National Research Health Insurance Database that contains claims data for the 2000 to 2011 period. A total of 27,050 patients were included in this study, 5410 of whom had received a hypothyroidism diagnosis. The prevalence of MD was high in patients with hypothyroidism (95% confidence interval [CI]: 1.14-1.51), especially in those older than 50 years old (P < .001). Although comorbidities such as hypertension or cirrhosis are significant risk factors for Menière's disease (P < .001, P < .05), the incidence rate of Menière's disease in patients with hypothyroidism differs significantly between groups without these comorbidities (95% CI: 1.14-1.95). Regarding the timing for the occurrence of Menière's disease in patients with hypothyroidism, there was a significant time interval of <5 years (P < .05). The risk of MD decreased after treatment with thyroxine and did not differ from that of the nonhypothyroidism cohort (adjusted HR [aHR] = 0.85, 95% CI: 0.66-1.11).The study demonstrates a significant association between hypothyroidism and Menière's disease, especially in elderly female patients. Physicians should consider verifying the thyroid function when encountering these patients.

Serum sickness disease in a patient with alopecia areata and Meniere' disease after PRP procedure

BACKGROUND

Platelet rich plasma procedure (PRP) is considered to be one of the safest aesthetic procedures. Adverse reactions after PRP administration are extreme rare.

PURPOSE

We present the patient with serum sickness disease (SSD) after PRP procedure.

OBJECTIVE AND METHODS

41 years old female suffers from alopecia areata for 5 years with frequent relapses and she has been suffering from Menier's disease recurrent symptoms for 6 years. The patient developed SSD after third PRP rejuvenating procedure and she has also noticed new alopecia areata lesions, but without Menier's disease symptoms. After SSD, 4 months later, she developed severe symptoms of Menier's disease with an episode of sudden sensorineural hearing loss. It alleviated only after intravenous administration of methylprednisolone. In our opinion, significant contraindication of PRP procedure is an autoimmune disease in the active phase.

Vincamine exerts protective effect on spiral ganglion neurons in endolymphatic hydrops guinea pig models

The aim of this study was to investigate the protective effects of vincamine in endolymphatic hydrops (ELH). After ELH guinea pigs treated by vincamine, the concentration of VAP in plasma, and the levels of cAMP, MDA, SOD, GSH-Px in right cochlea were measured using spectrophotometric method. The V2R, NMDAR1, p-NMDAR1, AQP2, p-AQP2, caspase3/9 and c-caspase3/9 expressions in right cochlea were detected using western blot analysis. The cochlear hydrops degree and SGNs density were evaluated by hemotoxylin and eosin staining (HE) test. Normal hearing and vestibular function were warranted by the tests of auditory brainstem response (ABR) and electronystagmography (ENG). After glutamate-injured SGNs treated with vincamine, the MDA, SOD GSH-Px, NGF, BDNF, NT3, NT4 and Trks levels were measured. Meanwhile, the Bcl2, Bax, NMDAR1, p-NMDAR1, PI3K, p-PI3K, Akt, p-Akt, caspase3/9 and cleaved-caspase3/9 expression levels were detected. Furthermore, the viability, apoptosis and necrosis of SGNs were tested by MTT and Hoechst/PI staining methods. The results indicated that vincamine could significantly inhibit the expression levels of cAMP, MDA, V2R, p-NMDAR1, p-AQP2 and c-caspase-3/-9 in cochlea, alleviate the cochlear hydrops degree, regulate the audiological and vestibular dysfunctions. The SGNs density, SOD and GSH-Px levels were also increased by vincamine. In vincamine-treating groups, the MDA, Bax, p-NMDAR1, and c-caspase3/9 levels were observably decreased, while SGNs survival, SOD, GSH, NGF, BDNF, NT3, NT4, Trks, Bcl2, p-PI3K, p-Akt expressions were improved. The present study indicated a novel use of vincamine in suppressing ELH formation by down-regulating the VAP/AQP2 signaling pathway. It also manifested that vincamine exerted protective effects on hearing via improving neurotrophin-dependent PI3K/Akt signaling pathway in SGNs.

Clinical Characteristics of Bilateral Meniere's Disease in a Single Asian Ethnic Group

OBJECTIVES/HYPOTHESIS

To identify the clinical characteristics of patients with bilateral Meniere's disease (MD) in an Asian population.

STUDY DESIGN

Cross-sectional retrospective study.

METHODS

We compared the clinical features of bilateral MD (BMD) and unilateral MD (UMD) in 320 Asian patients with single ethnicity. Demographic variables; age of onset; inner ear function; the coexistence of related disorders such as vestibular migraine, delayed MD, systemic autoimmune diseases, and familial MD; and prognoses were analyzed and compared.

RESULTS

The overall prevalence of BMD was 5.6%. The mean age of disease onset was 40.3 ± 14.8 and 47.0 ± 14.1 years for patients with BMD and UMD, respectively (P = .07). Demographic variables were not significantly different between patients with BMD and UMD (P > .05). Inner ear function, evaluated by hearing thresholds, caloric tests, and cervical vestibular evoked myogenic potentials, was significantly more deteriorated in the first involved ear of patients with BMD than in the second involved ear or the affected side of patients with UMD (P < .05). Among the comorbid conditions, only the prevalence of delayed MD was significantly higher in patients with BMD than in patients with UMD. Systemic autoimmune disease was found in only three patients with UMD. There was no significant prognostic difference between patients with UMD and BMD (P > .05).

CONCLUSIONS

A low prevalence of BMD, a higher frequency of delayed MD in BMD patients, and a low frequency of systemic autoimmune diseases in both UMD and BMD patients are significant findings in an Asian population.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:1191-1196, 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.

Proinflammatory cytokines and response to molds in mononuclear cells of patients with Meniere disease

Epidemiological studies have found a higher prevalence of allergic symptoms and positive prick tests in patients with Meniere’s disease (MD); however the effect of allergenic extracts in MD has not been established. Thus, this study aims to determine the effect of Aspergillus and Penicillium stimulation in cytokine release and gene expression profile in MD. Patients with MD showed higher basal levels of IL-1β, IL-1RA, IL-6 and TNF-α when compared to healthy controls. We observed that IL-1β levels had a bimodal distribution suggesting two different subgroups of patients, with low and high basal levels of cytokines. Gene expression profile in peripheral blood mononuclear cells (PBMC) showed significant differences in patients with high and low basal levels of IL-1β. We found that both mold extracts triggered a significant release of TNF-α in MD patients, which were not found in controls. Moreover, after mold stimulation, MD patients showed a different gene expression profile in PBMC, according to the basal levels of IL-1β. The results indicate that a subset of MD patients have higher basal levels of proinflammatory cytokines and the exposure to Aspergillus and Penicillium extracts may trigger additional TNF-α release and contribute to exacerbate inflammation.

Advances in the development of human protein microarrays

INTRODUCTION

High-content protein microarrays in principle enable the functional interrogation of the human proteome in a broad range of applications, including biomarker discovery, profiling of immune responses, identification of enzyme substrates, and quantifying protein-small molecule, protein-protein and protein-DNA/RNA interactions. As with other microarrays, the underlying proteomic platforms are under active technological development and a range of different protein microarrays are now commercially available. However, deciphering the differences between these platforms to identify the most suitable protein microarray for the specific research question is not always straightforward. Areas covered: This review provides an overview of the technological basis, applications and limitations of some of the most commonly used full-length, recombinant protein and protein fragment microarray platforms, including ProtoArray Human Protein Microarrays, HuProt Human Proteome Microarrays, Human Protein Atlas Protein Fragment Arrays, Nucleic Acid Programmable Arrays and Immunome Protein Arrays. Expert commentary: The choice of appropriate protein microarray platform depends on the specific biological application in hand, with both more focused, lower density and higher density arrays having distinct advantages. Full-length protein arrays offer advantages in biomarker discovery profiling applications, although care is required in ensuring that the protein production and array fabrication methodology is compatible with the required downstream functionality.

Regulation of Fn14 Receptor and NF-κB Underlies Inflammation in Meniere's Disease

Meniere’s disease (MD) is a rare disorder characterized by episodic vertigo, sensorineural hearing loss, tinnitus, and aural fullness. It is associated with a fluid imbalance between the secretion of endolymph in the cochlear duct and its reabsorption into the subarachnoid space, leading to an accumulation of endolymph in the inner ear. Epidemiological evidence, including familial aggregation, indicates a genetic contribution and a consistent association with autoimmune diseases (AD). We conducted a case–control study in two phases using an immune genotyping array in a total of 420 patients with bilateral MD and 1,630 controls. We have identified the first locus, at 6p21.33, suggesting an association with bilateral MD [meta-analysis leading signal rs4947296, OR = 2.089 (1.661–2.627); p = 1.39 × 10⁻⁰⁹]. Gene expression profiles of homozygous genotype-selected peripheral blood mononuclear cells (PBMCs) demonstrated that this region is a trans-expression quantitative trait locus (eQTL) in PBMCs. Signaling analysis predicted several tumor necrosis factor-related pathways, the TWEAK/Fn14 pathway being the top candidate (p = 2.42 × 10⁻¹¹). This pathway is involved in the modulation of inflammation in several human AD, including multiple sclerosis, systemic lupus erythematosus, or rheumatoid arthritis. In vitro studies with genotype-selected lymphoblastoid cells from patients with MD suggest that this trans-eQTL may regulate cellular proliferation in lymphoid cells through the TWEAK/Fn14 pathway by increasing the translation of NF-κB. Taken together; these findings suggest that the carriers of the risk genotype may develop an NF-κB-mediated inflammatory response in MD.

RNA-sequencing study of peripheral blood mononuclear cells in sporadic Ménière's disease patients: possible contribution of immunologic dysfunction to the development of this disorder

To date, the pathogenesis of Ménière's disease (MD) remains unclear. This study aims to investigate the possible relationship between potential immune system-related genes and sporadic MD. The whole RNA-sequencing (RNA-seq) technology was used to analyse the transcriptome of peripheral blood mononuclear cells of three MD patients and three control individuals. Of 366 differentially expressed genes (DEGs), 154 genes were up-regulated and 212 genes were down-regulated (|log₂ fold change| > 1 and P < 0·05). Gene ontology (GO) enrichment analysis illustrated that immune relevant factors played a key role in the pathogenesis of MD. Of 366 DEGs, we focused upon analysing the possible immune-related genes, among which the significantly up-regulated genes [glutathione S-transferase mu 1 (GSTM1), transmembrane protein 176 (TMEM176)B, TMEM176A] and down-regulated genes [solute carrier family 4 member (SLC4A)10 and SLC4A1] especially drew our attention. The mRNA expression levels of GSTM1, TMEM176B, TMEM176A, SLC4A1 and SLC4A10 were analysed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The serum concentration of GSTM1, TMEM176B and SLC4A10 proteins were measured by enzyme-linked immunosorbent assay (ELISA). Considering the results of qRT-PCR and ELISA, it was noteworthy that GSTM1 exhibited the highest fold change between two groups, which was consistent with the deep sequencing results by RNA-seq. In conclusion, our study first offers a new perspective in MD development on the basis of RNA expression patterns, suggesting that immune factors might be involved in the MD pathogenesis. Remarkably, GSTM1 might be a possible candidate gene for the diagnostic biomarker of MD and provides the basis for further biological and functional investigations.

Extended phenotype and clinical subgroups in unilateral Meniere disease: A cross-sectional study with cluster analysis

OBJECTIVES

To define clinical subgroups by cluster analysis in patients with unilateral Meniere disease (MD) and to compare them with the clinical subgroups found in bilateral MD.

DESIGN

A cross-sectional study with a two-step cluster analysis.

SETTINGS

A tertiary referral multicenter study.

PARTICIPANTS

Nine hundred and eighty-eight adult patients with unilateral MD.

MAIN OUTCOME MEASURES

best predictors to define clinical subgroups with potential different aetiologies.

RESULTS

We established five clusters in unilateral MD. Group 1 is the most frequently found, includes 53% of patients, and it is defined as the sporadic, classic MD without migraine and without autoimmune disorder (AD). Group 2 is found in 8% of patients, and it is defined by hearing loss, which antedates the vertigo episodes by months or years (delayed MD), without migraine or AD in most of cases. Group 3 involves 13% of patients, and it is considered familial MD, while group 4, which includes 15% of patients, is linked to the presence of migraine in all cases. Group 5 is found in 11% of patients and is defined by a comorbid AD. We found significant differences in the distribution of AD in clusters 3, 4 and 5 between patients with uni- and bilateral MD.

CONCLUSIONS

Cluster analysis defines clinical subgroups in MD, and it extends the phenotype beyond audiovestibular symptoms. This classification will help to improve the phenotyping in MD and facilitate the selection of patients for randomised clinical trials.

Innate immune defense in the inner ear - mucines are expressed by the human endolymphatic sac

The human endolymphatic sac has been shown recently to have immunological capacities and has thus been proposed as the main entity protecting the inner ear from pathogen invasion, equivalent to mucosa-associated lymphoid tissue (MALT). Although the sac expresses molecules of the innate immune system, the potential expression of members of the important mucin family has not been detailed. Thus, this paper explores endolymphatic sac expression of a number of mucins and mucin precursors. Twelve fresh tissue samples from the human endolymphatic sac were obtained during translabyrinthine surgery. The expression of Mucin 1, 2, 5B/AC and 16, as well as the core structure elements (mucin precursors) T-antigen, Tn-antigen and Sialyl-Tn-antigen was investigated by immunohistochemistry. The endolymphatic sac epithelium expressed MUC1 (both apically towards the endolymphatic sac (ES) lumen and basally towards the capillary network), MUC 16 and Tn-antigen. There was no labeling after incubation with antibodies against T-antigen, sialyl-Tn-antigen, MUC2 and MUC5B/AC. We conclude that the human endolymphatic sac epithelium expresses a number of mucin molecules, which supports the hypothesis of the sac as the primary immunological tissue structure of the inner ear, equivalent to MALT in other organs. The mucins may also play a role in the formation and continuous homeostasis of the inner ear fluids, as well as the pathogenesis of Meniere's disease.

An Exploratory Study to Detect Ménière's Disease in Conventional MRI Scans Using Radiomics

OBJECTIVE

The purpose of this exploratory study was to investigate whether a quantitative image analysis of the labyrinth in conventional magnetic resonance imaging (MRI) scans using a radiomics approach showed differences between patients with Ménière's disease (MD) and the control group.

MATERIALS AND METHODS

In this retrospective study, MRI scans of the affected labyrinths of 24 patients with MD were compared to the MRI scans of labyrinths of 29 patients with an idiopathic asymmetrical sensorineural hearing loss. The 1.5- and 3-T MRI scans had been previously made in a clinical setting between 2008 and 2015. 3D Slicer 4.4 was used to extract several substructures of the labyrinth. A quantitative analysis of the normalized radiomic image features was performed in Mathematica 10. The image features of the two groups were statistically compared.

RESULTS

For numerous image features, there was a statistically significant difference (p-value <0.05) between the MD group and the control group. The statistically significant differences in image features were localized in all the substructures of the labyrinth: 43 in the anterior semicircular canal, 10 in the vestibule, 22 in the cochlea, 12 in the posterior semicircular canal, 24 in the horizontal semicircular canal, 11 in the common crus, and 44 in the volume containing the reuniting duct. Furthermore, some figures contain vertical or horizontal bands (three or more statistically significant image features in the same image feature). Several bands were seen: 9 bands in the anterior semicircular canal, 1 band in the vestibule, 3 bands in the cochlea, 0 bands in the posterior semicircular canal, 5 bands in the horizontal semicircular canal, 3 bands in the common crus, and 10 bands in the volume containing the reuniting duct.

CONCLUSION

In this exploratory study, several differences were found in image features between the MD group and the control group by using a quantitative radiomics approach on high resolution T2-weighted MRI scans of the labyrinth. Further research should be aimed at validating these results and translating them in a potential clinical diagnostic method to detect MD in MRI scans.