Towards personalized medicine in Ménière's disease

Cupping Therapy as a Potential Complimentary Treatment for Meniere's Disease: A Case Report

Meniere's disease is defined by the presence of three essential symptoms: episodic vertigo, tinnitus, and sensorineural hearing loss. The mainstay of its management constitutes lifestyle modification and medical and surgical therapies. Cupping therapy is an ancient treatment that is still widely used especially in the Middle East, Africa, and the United Kingdom. This study portraits the case of a 54-year-old patient suffering from long-standing Meniere's disease. The patient was treated with the routine treatment that was to no avail. It was decided that the patient undergoes cupping therapy. Over two years of monthly cupping therapy sessions, the patient reported a decrease in intensity and frequency of symptoms until its disappearance. Cupping therapy has shown a positive outcome on the patient. According to our search, there is a previous case report published in 2020 that shares multiple similarities with our case. Further studies on cupping therapy and its efficacy, mechanism of action, and complications on a larger scale are advised.

Development and validation of prediction model to estimate vertigo risk after endolymphatic sac decompression in Meniere's disease: a retrospective cohort study

PURPOSE

To study the efficacy predictors of endolymphatic sac decompression (ESD) in Meniere's disease (MD), and to establish and verify the prediction model of vertigo after ESD in patients with MD.

METHODS

The retrospective cohort data of 56 patients with unilateral MD who underwent ESD surgery were recorded. A stepwise regression method was used to select optimal modeling variables, and we established a logistic regression model with the outcome of vertigo after ESD. The bootstrap method was used for internal validation.

RESULTS

Potential predictors included sex, age, follow-up duration, disease course, attack duration, frequency of attack, pure-tone threshold average (PTA) of the patient's speech frequency, audiogram type, glycerin test results, MD subtype, and 10-year atherosclerotic cardiovascular disease risk classification. Using the stepwise regression method, we found that the optimal modeling variables were the audiogram type and PTA of the patient's speech frequency. The prediction model based on these two variables exhibited good discrimination [area under the receiver operating characteristic curve: 0.72 (95% confidence interval: 0.57-0.86)] and acceptable calibration (Brier score 0.21).

CONCLUSION

The present model based on the audiogram type and PTA of the patient's speech frequency was found to be useful in guidance of ESD efficacy prediction and surgery selection.

The effect of vestibular rehabilitation in Meniere's disease: a systematic review and meta-analysis of clinical trials

BACKGROUND

Meniere's disease (MD) is a complex disease that can severely affect the quality of life. In this systematic review and meta-analysis, we aimed to investigate the effect of vestibular rehabilitation (VR) versus control/other interventions on the quality of life in patients with MD.

METHODS

We searched six electronic databases (PubMed/MEDLINE, Web of Science, EMBASE, Scopus, ProQuest, CENTRAL) from inception to September 30, 2022 with no language restriction for publications comparing the effect of VR with control/ other interventions in patients with MD. The primary outcome was quality of life assessed by dizziness handicap inventory (DHI).

RESULTS

Overall, three studies with a total of 465 patients were included in the meta-analysis. All the included studies reported immediate-term DHI scores. A medium effect (standardized mean difference [SMD] = - 0.58, 95% confidence interval [CI] - 1.12; - 0.05) was observed favoring the use of VR to improve DHI scores in patients with MD in the immediate term. Moreover, there was severe heterogeneity in immediate DHI scores among the included studies (χ2 = 22.33, P = 0.00, I2 = 82.1%).

CONCLUSIONS

VR rehabilitation can improve the quality of life in patients with MD immediately after treatment. Since all the included studies had a high risk of bias and none had long-term follow-ups, further high-quality research is required to determine the short-, intermediate-, and long-term effects of VR compared to control/other interventions.

A Continuously Worn Dual Temperature Sensor System for Accurate Monitoring of Core Body Temperature from the Ear Canal

The objective of this work was to develop a temperature sensor system that accurately measures core body temperature from an ear-worn device. Two digital temperature sensors were embedded in a hearing aid shell along the thermal gradient of the ear canal to form a linear heat balance relationship. This relationship was used to determine best fit parameters for estimating body temperature. The predicted body temperatures resulted in intersubject limits of agreement (LOA) of ±0.49 °C over a range of physiologic and ambient temperatures without calibration. The newly developed hearing aid-based temperature sensor system can estimate core body temperature at an accuracy level equal to or better than many devices currently on the market. An accurate, continuously worn, temperature monitoring and tracking device may help provide early detection of illnesses, which could prove especially beneficial during pandemics and in the elderly demographic of hearing aid wearers.

The NLRP3 inflammasome as a target for sensorineural hearing loss

Sensorineural hearing loss is the most common type of hearing loss in adults and occurs due to damage of the inner ear caused by a range of factors including ageing, excessive noise, toxins, and cancer. Auto-inflammatory disease is also a cause of hearing loss and there is evidence that inflammation could contribute to hearing loss in other conditions. Within the inner ear there are resident macrophage cells that respond to insults and whose activation correlates with damage. The NLRP3 inflammasome is a multi-molecular pro-inflammatory protein complex that forms in activated macrophages and may contribute to hearing loss. The aim of this article is to discuss the evidence for the NLRP3 inflammasome and associated cytokines as potential therapeutic targets for sensorineural hearing loss in conditions ranging from auto-inflammatory disease to tumour-induced hearing loss in vestibular schwannoma.

Serum/glucocorticoid-inducible kinase 1 deficiency induces NLRP3 inflammasome activation and autoinflammation of macrophages in a murine endolymphatic hydrops model

Ménière's disease, a multifactorial disorder of the inner ear, is characterized by severe vertigo episodes and hearing loss. Although the role of immune responses in Ménière's disease has been proposed, the precise mechanisms remain undefined. Here, we show that downregulation of serum/glucocorticoid-inducible kinase 1 is associated with activation of NLRP3 inflammasome in vestibular-resident macrophage-like cells from Ménière's disease patients. Serum/glucocorticoid-inducible kinase 1 depletion markedly enhances IL-1β production which leads to the damage of inner ear hair cells and vestibular nerve. Mechanistically, serum/glucocorticoid-inducible kinase 1 binds to the PYD domain of NLRP3 and phosphorylates it at Serine 5, thereby interfering inflammasome assembly. Sgk^-/- mice show aggravated audiovestibular symptoms and enhanced inflammasome activation in lipopolysaccharide-induced endolymphatic hydrops model, which is ameliorated by blocking NLRP3. Pharmacological inhibition of serum/glucocorticoid-inducible kinase 1 increases the disease severity in vivo. Our studies demonstrate that serum/glucocorticoid-inducible kinase 1 functions as a physiologic inhibitor of NLRP3 inflammasome activation and maintains inner ear immune homeostasis, reciprocally participating in models of Ménière's disease pathogenesis.

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.

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.

Efficacy and Durability of Intratympanic Gentamicin Treatment for Meniere's Disease

Objective: To study the success of intratympanic gentamicin (ITG) treatment in reducing vertigo attacks in Meniere's disease (MD) and the value of the Halmagyi head thrust test (HTT) in predicting treatment durability. Study Design: Retrospective cohort study. Setting: Tertiary care vestibular clinic. Patients: Unilateral MD patients treated with ITG from 2006-2019 with ≥6 months follow-up. Main Outcome Measures: Demographics, audiometric data, subjective symptomatology, and HTT results were collected. Treatment success was defined as sufficient symptom relief. Treatment failure indicated vertigo control of less than 6 months duration. Treatment relapse indicated vertigo recurrence after 6 months. Results: Of 255 patients, treatment success, failure, and relapse occurred in 226 (88.6%), 29 (11.4%), and 121 (47.1%) patients, respectively. 48 (18.8%) patients who failed to respond or relapsed underwent labyrinthectomy. Mean follow-up time was 3.7 yrs (range 0.5-12.8). After ITG treatment, 25% patients reported worse hearing; mean pure tone average (PTA) increased by 18.6 ± 11.3 dB and mean word recognition score (WRS) decreased by 33 ± 21%. Of the 148 patients with negative pre-treatment HHT, 103 (69.6%) converted to positive after ITG treatment. Mean time-to-relapse in the converted and non-converted HTT cohorts was significantly different (49.7 vs. 27.0 months, p = 0.009) even after adjusting for gender, age, laterality, duration of symptoms, and number of ITG treatments. There were no significant differences between the two groups in hearing outcomes or subjective symptoms (e.g. lingering disequilibrium). Conclusions: ITG treatment effectively reduces the number of vertigo attacks in MD. HTT is valuable in predicting durability of treatment benefit.

Increased Monocyte Chemotactic Protein-1 Accompanying Pro-Inflammatory Processes are Associated with Progressive Hearing Impairment and Bilateral Disability of Meniere's Disease

BACKGROUND

The progression of hearing impairment and the bilateral involvement of Meniere's disease (MD) may depend on the disease duration and aging. Recent studies reported that MD might involve dysfunction of the microvascular circulation damaged due to inflammatory changes.

OBJECTIVES

The aim of this study was to determine that the progress of the MD's hearing impairment and bilateral disability may be associated with the pathogenesis of several pro-inflammatory processes.

PATIENTS AND METHODS

We recruited 30 unilateral MD patients (56.8 ± 14.7 years old), 7 bilateral MD patients (65.3 ± 13.9 years old), and 17 age-matched control subjects (53.5 ± 14.4 years old, p > 0.05). We measured the plasma vascular endothelial growth factor (VEGF), plasma interleukin-6 (IL-6), plasma tumor-necrosis factor α (TNFα), and plasma monocyte chemotactic protein-1 (MCP-1).

RESULTS

The bilateral MD group and the unilateral MD group had higher plasma MCP-1 (204.7 ± 41.0 pg/mL and 169.5 ± 32.0 pg/mL) than the control group (149.2 ± 30.7 pg/mL) (p < 0.05). There was no significant difference in plasma TNFα, IL-6, and VEGF among 3 groups (p > 0.05). There was a strong correlation between the plasma MCP-1 and age in MD patients (r = 0.58, p < 0.01); however, no significant correlation between the plasma MCP-1 and age was found in control subjects (p > 0.05). The plasma MCP-1 significantly correlated with the average hearing level of 500, 1,000, 2,000, and 4,000 Hz, and the maximum slow phase eye velocity in caloric test in the better side (p < 0.05). Also, the plasma MCP-1 showed significant positive correlations with the plasma IL-6 (r = 0.49, p < 0.01) and plasma TNFα (r = 0.32, p < 0.05) in MD group.

CONCLUSIONS

Our results suggest that the increased plasma MCP-1 accompanying pro-inflammatory processes are associated with the progression of the hearing impairment and the bilateral disability of MD.

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.

Diagnosis of Menière's disease according to the criteria of 2015: Characteristics and challenges in 96 patients

BACKGROUND

The diagnosis of Menière's disease (MD) is made according to diagnostic criteria, the last revision of which was in 2015. For diagnosis, symptoms are weighted with audiometric findings and this can be challenging in individual patients.

OBJECTIVE

To analyze patient's characteristics and symptoms in a real-life cohort of 96 patients with diagnosed MD regarding sociodemographic parameters, clinical specifics, and audiometry.

METHODS

Prospective clinical patient registry containing demographic and socioeconomic parameters, symptoms, as well as pure-tone audiometry data.

RESULTS

31 patients with definite MD, and 36 with probable MD were identified. 29 patients showed typical clinical signs of MD, but did not meet the full diagnostic criteria, and were considered separately. Mean duration of symptoms prior to presentation was 3.9±4.6 years. Significant differences between categories were found regarding aural fullness, tinnitus, and fluctuating hearing. If multiple audiograms were available, 28.6 %(6/21) documented fluctuating hearing.

CONCLUSIONS

Current diagnostic criteria probably do not represent patients with monosymptomatic presentation or an early stage very well. Long-term follow-up with repeated audiometry is advisable.

First-in-human intracochlear application of human stromal cell-derived extracellular vesicles

Extracellular vesicles (EVs) derived from the secretome of human mesenchymal stromal cells (MSC) contain numerous factors that are known to exert anti‐inflammatory effects. MSC‐EVs may serve as promising cell‐based therapeutics for the inner ear to attenuate inflammation‐based side effects from cochlear implantation which represents an unmet clinical need. In an individual treatment performed on a ‘named patient basis’, we intraoperatively applied allogeneic umbilical cord‐derived MSC‐EVs (UC‐MSC‐EVs) produced according to good manufacturing practice. A 55‐year‐old patient suffering from Menière's disease was treated with intracochlear delivery of EVs prior to the insertion of a cochlear implant. This first‐in‐human use of UC‐MSC‐EVs demonstrates the feasibility of this novel adjuvant therapeutic approach. The safety and efficacy of intracochlear EV‐application to attenuate side effects of cochlea implants have to be determined in controlled clinical trials.

Genetics and the Individualized Therapy of Vestibular Disorders

Background: Vestibular disorders (VDs) are a clinically divergent group of conditions that stem from pathology at the level of the inner ear, vestibulocochlear nerve, or central vestibular pathway. No etiology can be identified in the majority of patients with VDs. Relatively few families have been reported with VD, and so far, no causative genes have been identified despite the fact that more than 100 genes have been identified for inherited hearing loss. Inherited VDs, similar to deafness, are genetically heterogeneous and follow Mendelian inheritance patterns with all modes of transmission, as well as multifactorial inheritance. With advances in genetic sequencing, evidence of familial clustering in VD has begun to highlight the genetic causes of these disorders, potentially opening up new avenues of treatment, particularly in Meniere's disease and disorders with comorbid hearing loss, such as Usher syndrome. In this review, we aim to present recent findings on the genetics of VDs, review the role of genetic sequencing tools, and explore the potential for individualized medicine in the treatment of these disorders.

Methods: A search of the PubMed database was performed for English language studies relevant to the genetic basis of and therapies for vestibular disorders, using search terms including but not limited to: “genetics,” “genomics,” “vestibular disorders,” “hearing loss with vestibular dysfunction,” “individualized medicine,” “genome-wide association studies,” “precision medicine,” and “Meniere's syndrome.”

Results: Increasing numbers of studies on vestibular disorder genetics have been published in recent years. Next-generation sequencing and new genetic tools are being utilized to unearth the significance of the genomic findings in terms of understanding disease etiology and clinical utility, with growing research interest being shown for individualized gene therapy for some disorders.

Conclusions: The genetic knowledge base for vestibular disorders is still in its infancy. Identifying the genetic causes of balance problems is imperative in our understanding of the biology of normal function of the vestibule and the disease etiology and process. There is an increasing effort to use new and efficient genetic sequencing tools to discover the genetic causes for these diseases, leading to the hope for precise and personalized treatment for these patients.

Identification of Potential Meniere's Disease Targets in the Adult Stria Vascularis

The stria vascularis generates the endocochlear potential and is involved in processes that underlie ionic homeostasis in the cochlear endolymph, both which play essential roles in hearing. The histological hallmark of Meniere's disease (MD) is endolymphatic hydrops, which refers to the bulging or expansion of the scala media, which is the endolymph-containing compartment of the cochlea. This histologic hallmark suggests that processes that disrupt ion homeostasis or potentially endocochlear potential may underlie MD. While treatments exist for vestibular symptoms related to MD, effective therapies for hearing fluctuation and hearing loss seen in MD remain elusive. Understanding the potential cell types involved in MD may inform the creation of disease mouse models and provide insight into underlying mechanisms and potential therapeutic targets. For these reasons, we compare published datasets related to MD in humans with our previously published adult mouse stria vascularis single-cell and single-nucleus RNA-Seq datasets to implicate potentially involved stria vascularis (SV) cell types in MD. Finally, we provide support for these implicated cell types by demonstrating co-expression of select candidate genes for MD within SV cell types.

Evaluation of Serum Immunoreactivity to Common Indigenous Iranian Inhalation and Food Allergens in Patients with Meniere's Disease

Background: A few studies investigated the relationship between allergy and Meniere disease considering complete allergen panel. We aimed to evaluate the serum immunoreactivity in patients with Meniere's disease (MD) compared with healthy people according to common indigenous Iranian inhalation and food allergens.Methods: Thirty-nine patients with MD referred to Rasoul Akram Hospital (Tehran, Iran) were evaluated and compared with a 41 membered control group. A panel of common inhalation and food allergens (using an immunoblotting method), as well as total immunoglobulin E (IgE) level (using the sandwich enzyme-linked immunosorbent assay method), were checked on the patients' serum.Results: The mean total IgE level was 193.85 ± 175.43 IU/ml in the patients with MD and 117.61 ± 138.05 IU/ml in the control group, which was significantly higher than the other subjects in the control group (P = .016). There was a significant difference between the two groups regarding inhalation allergens such as; sweet vernal grass, cultivated rye, cultivated oat, Russian thistle, goosefoot, and rough pigweed (P = .01-0.038). Patients with MD reported more reactive to food allergens such as; rye flour, hazelnut, pepper, citrus mix 2, potato, strawberry, and celery allergens. There was a significant relationship between Meniere and serum immunoreactivity to inhalation and food allergens (both P = .001).Conclusion: Serum total IgE level in patients with MD (in both inhalation and food allergens groups) was higher than the control group, and there was a relationship between MD and immunoreactivity to common indigenous inhalation and food allergens of Iran.

FAM136A immunoreactivity is associated with nodal involvement and survival in lung adenocarcinoma in a Chinese case series

Lung cancer patients with lymph node metastasis usually had short overall survival and occurred distant metastases at the early stage. However, some of these people did have more prolonged survival. The underlying reason is still unclear. In this study, we found a novel molecule, family with sequence similarity 136, member A gene (FAM136A). First, we performed immunohistochemistry for FAM136A in 177 lung carcinoma tissues. Second, we carried out in vitro studies by using A549 and PC-9. We detected FAM136A immunoreactivity in 79 out of 177 (44.6%) lung carcinoma tissues, and the FAM136A status was significantly associated with tumor T stage, lymph node metastasis, and the Tumor-Node-Metastasis (TNM) staging system in these cases. Importantly, it was significantly associated with the overall survival of the patients with lymph node metastasis, especially FAM136A positive patients, who had worse outcomes. Subsequent in vitro experiments revealed that the proliferation activity and migration property decreased both A549 and PC-9 lung carcinoma cells transfected with siRNA-FAM136A, and apoptosis reduced. Meanwhile, the expression of CDK4 and CDK6 decreased. FAM136A status would be a potent, worse prognostic factor in lung cancer patients with lymph node metastasis. It would play a vital role in the proliferation, apoptosis, and migration properties of A549 and PC-9. In the future, We will focus on the uncovered signal mechanism between FAM136A and lung cancer.

Cannabinoids, Inner Ear, Hearing, and Tinnitus: A Neuroimmunological Perspective

Cannabis has been used for centuries for recreational and therapeutic purposes. Whereas, the recreative uses are based on the psychotropic effect of some of its compounds, its therapeutic effects range over a wide spectrum of actions, most of which target the brain or the immune system. Several studies have found cannabinoid receptors in the auditory system, both at peripheral and central levels, thus raising the interest in cannabinoid signaling in hearing, and especially in tinnitus, which is affected also by anxiety, memory, and attention circuits where cannabinoid effects are well described. Available studies on animal models of tinnitus suggest that cannabinoids are not likely to be helpful in tinnitus treatment and could even be harmful. However, the pharmacology of cannabinoids is very complex, and most studies focused on neural CB1R-based responses. Cannabinoid effects on the immune system (where CB2Rs predominate) are increasingly recognized as essential in understanding nervous system pathological responses, and data on immune cannabinoid targets have emerged in the auditory system as well. In addition, nonclassical cannabinoid targets (such as TRP channels) appear to play an important role in the auditory system as well. This review will focus on neuroimmunological mechanisms for cannabinoid effects and their possible use as protective and therapeutic agents in the ear and auditory system, especially in tinnitus.

Clinical and molecular genetics of Meniere disease

Meniere disease (MD) represents a heterogeneous group of relatively rare disorders of the inner ear that causes vertigo attacks, fluctuating sensorineural hearing loss (SNHL) involving low and medium frequencies, tinnitus, and aural fullness. MD has been attributed to an accumulation of endolymph in the cochlear duct. The diagnosis of MD is based on the phenomenological association of clinical symptoms including SNHL during the vertigo attacks. At least two mechanisms are involved in MD: (a) a pro-inflammatory immune response mediated by interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNFα), and IL-6, and (b) nuclear factor-kappa B (NF-κB)-mediated inflammation in the carriers of the single nucleotide variant rs4947296. The majority of MD cases are considered sporadic, although familial aggregation has been recognized in European and East Asian populations in multiplex families, supporting a genetic contribution to the disease. In sporadic MD cases, the main genetic findings involve multiplex rare variants in several SNHL genes, such as GJB2, USH1G, SLC26A4, ESRRB, and CLDN14, and axonal guidance signaling genes, such as NTN4 and NOX3. Familial aggregation has been reported in 6–8 % of MD cases, and most families show an autosomal dominant inheritance. Few rare missense heterozygous variants have been described in simplex families in six genes (COCH, FAM136A, DTNA, PRKCB, SEMA3D, and DPT). Of note, 33 % of familial MD individuals show singleton and multiplex rare missense variants in the OTOG gene, suggesting a multiallelic inheritance. Moreover, potentially pathogenic rare variants in the familial genes FAM136A, DTNA, and DPT have been reported in Korean singletons with sporadic MD. Rare variants may have a significant contribution to sporadic and familial MD. The interaction of common cis-regulatory variants located in non-coding regions and rare variants in coding regions in one or more genes will determine the variation on the phenotype in MD. Further studies on genotype–phenotype correlations are required to improve the yield of genetic diagnosis, and different types of variants seem to contribute to the genetic structure of MD.

Single Cell and Single Nucleus RNA-Seq Reveal Cellular Heterogeneity and Homeostatic Regulatory Networks in Adult Mouse Stria Vascularis

The stria vascularis (SV) generates the endocochlear potential (EP) in the inner ear and is necessary for proper hair cell mechanotransduction and hearing. While channels belonging to SV cell types are known to play crucial roles in EP generation, relatively little is known about gene regulatory networks that underlie the ability of the SV to generate and maintain the EP. Using single cell and single nucleus RNA-sequencing, we identify and validate known and rare cell populations in the SV. Furthermore, we establish a basis for understanding molecular mechanisms underlying SV function by identifying potential gene regulatory networks as well as druggable gene targets. Finally, we associate known deafness genes with adult SV cell types. This work establishes a basis for dissecting the genetic mechanisms underlying the role of the SV in hearing and will serve as a basis for designing therapeutic approaches to hearing loss related to SV dysfunction.

Are viral-infections associated with Ménière's Disease? A systematic review and meta-analysis of molecular-markers of viral-infection in case-controlled observational studies of MD

Despite considerable research, it remains controversial as to whether viral-infections are associated with Meniere’s Disease (MD), a clinically heterogeneous set of chronic inner-ear disorders strongly associated with endolymphatic hydrops. Here, we investigated whether viral-infections are associated with MD through a systematic review and meta-analysis of observational clinical studies using molecular-diagnostics. Eligible for inclusion were case-controlled studies which ascertained molecular-determinants of past or present viral-infection through either viral nucleic acids or host serological marker in MD cases and non-MD controls. Across online databases and grey literature, we identified 210 potentially relevant articles in the English language, from which a total of 14 articles fully satisfied our eligibility criteria such that meta-groups of 611 MD-cases and 373 controls resulted. The aggregate quality of the modest-sized (14 studies) body of evidence was limited and varied considerably with regards to participant selection, matching, and ascertainment(s) and determinant(s) of viral-infection. Most data identified concerned the human cytomegalovirus (CMV), and meta-analysis of eligible studies revealed that evidence of CMV-infection was associated approximately three-fold with MD compared to controls, however the timing of the infections was indeterminate as the pooled analyses combined antiviral serological markers with viral nucleic acid markers. No association was found for any of HSV-1, -2, VZV, or EBV. Associative analyses of any viral species not aforementioned were precluded by limited data, and thus potential associations between other viral species and MD, especially other than Herpesviridae, are yet to be characterised. Overall, we have found a small association between CMV-infection and MD, however it is to be determined for what sub-groups of MD this finding may be relevant, and ideally the reported association remains would be reproduced by a greater volume of higher quality evidence.

Relationship between changes in hearing function and volumes of endolymphatic hydrops after endolymphatic sac drainage

Background: Endolymphatic sac drainage (ELSD) may have a positive effect on endolymphatic hydrops (EH) and may help to preserve inner ear function. However, the relationship between changes in EH volumes and hearing function after ELSD has not been described. Objectives: We aimed to reveal the factors related to changes in hearing and EH following ELSD. Material and Methods: Twenty-one patients who received ELSD were enrolled. Pure tone audiometry and 3-T magnetic resonance imaging (MRI) 4 h after intravenous injection of gadolinium enhancement were performed just before surgery and 2 years later. To characterize the endolymphatic space (ELS), we measured the volume of the total fluid (TFS) and ELS and calculated the ratio of ELS to TFS (ELS ratio). Results: The ELS ratio of the patients who showed hearing improvement was 18.5 ± 11.4% before surgery and 23.9 ± 14.3% after. For those with no change, it was 29.7 ± 10.8% before and 29.4 ± 9.5% after, and in patients with worsened hearing function it was 22.7 ± 7.5% before and 27.2 ± 13.4% after. Conclusion: We found no correlation between the changes in hearing function and the volume of EH after ELSD.

Three-Dimensional Magnetic Resonance Imaging Reveals the Relationship Between the Control of Vertigo and Decreases in Endolymphatic Hydrops After Endolymphatic Sac Drainage With Steroids for Meniere's Disease

Meniere's disease is a common disease, that presents with recurrent vertigo and cochlear symptoms. The pathology of Meniere's disease was first reported to involve endolymphatic hydrops in 1938. The endolymphatic sac is thought to have a role to keep the hydrostatic pressure and endolymph homeostasis for the inner ear. As a surgery for intractable Meniere's disease, endolymphatic sac drainage with intraendolymphatic sac application of large doses of steroids is performed to control the endolymphatic hydrops and preserve or improve inner ear function. In the present study, to observe the effect of this surgery, we calculated the endolymphatic space size using 3-Tesla magnetic resonance imaging (MRI) 4 h after intravenous injection of gadolinium enhancement at two time points: just before surgery and 2 years after. To reveal the condition of the endolymphatic space, we constructed three-dimensional MR images semi-automatically and fused the three-dimensional images of the total fluid space of inner ear and the endolymphatic space. After fusing the images, we calculated the volume of the total fluid space and endolymphatic space. Two years after surgery, 16 of 20 patients (80.0%) showed relief from vertigo/dizziness and reductions in the ratio of the volume of the endolymphatic size to the total fluid space of inner ear. Endolymphatic sac drainage with intraendolymphatic sac application of large doses of steroids could control vertigo/dizziness and decrease the endolymphatic hydrops. These results indicate that endolymphatic sac drainage is a good treatment option for patients with intractable Meniere's disease. In addition, volumetric measurement of inner ear volume could be useful for confirming the effect of treatments on Meniere's disease.