Ménière's Disease: Molecular Analysis of Aquaporins 2, 3 and Potassium Channel KCNE1 Genes in Brazilian Patients

The impact of COVID-19 and vaccination status on outcomes in veterans with head and neck squamous cell carcinoma

BACKGROUND

The impact of both COVID-19 infection and vaccination status on patients with head and neck squamous cell carcinoma (HNSCC) remains unknown.

OBJECTIVE

To determine the impact of COVID-19 infection and vaccination status on 60-day mortality, cardiovascular, and respiratory complications in patients with a prior diagnosis of HNSCC.

METHODS

This was a retrospective cohort study through the Veterans Affairs (VA) Corporate Data Warehouse of Veterans with HNSCC who were tested for COVID-19 during any inpatient VA medical center admission. A cohort of patients was created of Veterans with a diagnosis of HNSCC of the oral cavity,oropharynx, hypopharynx, larynx, and nasopharynx based on International Classification of Disease (ICD) codes. Data collected included clinical/demographic data, vaccination status, and incidence of 60-day mortality, 60-day cardiovascular complication (including myocardial infarction, venous thromboembolism, cerebrovascular accident), and 60-day respiratory complication (including acute respiratory failure, acute respiratory distress syndrome, and pneumonia). The interactions between COVID-19 infection, vaccination status, morbidity and mortality were investigated.

RESULTS

Of the 14 262 patients with HNSCC who were tested for COVID-19 during inpatient admission, 4754 tested positive (33.3%), and 9508 (67.7%) tested negative. Patients who tested positive demonstrated increased 60-day mortality (4.7% vs. 2.0%, respectively; p < 0.001), acute respiratory failure (ARF; 15.4% vs. 7.1%, p < 0.001), acute respiratory distress syndrome (ARDS; 0.9% vs. 0.2%, p < 0.001), and pneumonia (PNA; 20.0% vs. 6.4%, p < 0.001) compared to those who never tested positive, respectively. Patients who received COVID-19 vaccination between 2 weeks and 6 months prior to a positive test demonstrated decreased rates of ARF (13.2% vs. 16.0%, p = 0.034) and PNA (16.7% vs. 20.9%, p = 0.003) compared to the unvaccinated group. A logistic regression of patients with COVID-19 infections who died within 60 days was performed, with no significant survival advantage among patients vaccinated between 2 weeks and 6 months prior to the positive test.

CONCLUSION

COVID-19 infection may significantly increase rates of 60-day mortality and respiratory complications in patients with HNSCC. COVID-19 vaccination between 2 weeks and 6 months prior to infection may decrease severity of respiratory complications but did not show significant mortality benefits in this study. These data highlight the need for surveillance of respiratory infection and vaccination in this vulnerable population.

Immunohistochemical localisation of aquaporin 2 and vasopressin type 2 receptor in the human endolymphatic sac

OBJECTIVE

This study aimed to determine the distribution and subcellular localisation of aquaporin 2 and vasopressin type 2 receptor in the human endolymphatic sac.

METHODS

Ten samples of human endolymphatic sac were collected during acoustic neurinoma removal using the translabyrinthine approach. Immunohistochemistry and immunofluorescence were performed using aquaporin 2 and vasopressin type 2 receptor monoclonal antibodies.

RESULTS

Confocal microscopy demonstrated that vasopressin type 2 receptor labelling was expressed in both the apical and basolateral plasma membranes, and in the cytoplasm of the endolymphatic sac epithelium, whereas aquaporin 2 was strongly expressed at the basolateral site of the endolymphatic sac epithelium, in both the intraosseous and extraosseous parts of the endolymphatic sac.

CONCLUSION

Both aquaporin 2 and vasopressin type 2 receptor were detected in the epithelial cells of the human endolymphatic sac, suggesting that this channel may be involved in inner-ear fluid homeostasis. However, strong basolateral expression of aquaporin 2 in endolymphatic sac epithelium suggested that the function of aquaporin 2 may differ between the endolymphatic sac and kidney.

Genetic advances in Meniere Disease

Meniere Disease (MD) is an idiopathic inner ear disease with complex etiology and pathogenesis, which is still unclear. With the development in gene analysis technology, the genetic research of MD has attracted extensive attention, resulting in a large number of studies on the research of the relationship between human genes and MD. This paper aims to review the studies on this topic in recent years. The studies mainly focused on the genetics of familial MD and the correlation between MD and potentially related functional genes. The results of these studies have demonstrated the complexity and diversity of the pathogenesis of MD with both genetic and epigenetic alterations, suggesting that MD might be related to inflammation, immunity, aqua and ion balance in the lymphatic fluid, virus infection, metabolism, and abnormal function of nerve conduction. The finding of rare mutations in TECTA, MYO7A and OTOG genes and other genes such as CDH23, PCDH15 and ADGRV1 in the same families suggest that the integrity of the stereocilia and their interaction with the tectorial and otolithic membranes could be involved in the pathophysiology of familial MD.

Pathogenesis and Etiology of Ménière Disease: A Scoping Review of a Century of Evidence

Importance

Ménière disease is a rare chronic benign disorder of the inner ear with a natural history of multiple clinical phenotypes of variable severity and a tendency to burnout with time. Although multiple treatment modalities have been shown to improve the disease process-some adversely affecting cochleovestibular function-it remains uncertain whether one, several separate, or a combination of pathophysiologic mechanisms affect the disease process. A scoping review of the evidence underlying proposed pathophysiologic mechanisms of Ménière disease is needed to determine which processes are most likely to be etiopathogenic factors.

Observations

Of the 4602 relevant articles found through Embase, Ovid, and PubMed, 444 met inclusion criteria. The most common reported causes of Ménière disease were autoimmune or immune-mediated, genetic, or structural dysfunction of the inner ear. During the study period from inception to March 2021, etiologic theories shifted from structural dysfunction to autoimmune and genetic causes of Ménière disease.

Conclusions and Relevance

This scoping review found that Ménière disease is a multifactorial disease with lifelong comorbidities and loss of quality-associated life-years whose most commonly reported causes were structural dysfunction, immunologic damage, and genetic susceptibility. Recent studies have examined how autoinflammatory processes and vestibular migraine may be associated with Ménière disease. Large heterogeneity among studies may be explained by historical differences in the clinical understanding of the disease, as well as evolving intervention methodologies and practitioner expertise. Ménière disease is a multifactorial disease with lifelong comorbidities and loss of quality-associated life-years; therefore, future studies of reliable biomarkers of endolymphatic hydrops and real-time imaging are warranted to improve understanding and treatment.

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.

The relationship between nutrition and Ménière's disease

Ménière's disease is an inner ear disease with attacks characterized by ear fullness, tinnitus, fluctuant sensorineural hearing loss and vertigo. Although pathophysiology of the disease is not fully known, endolymphatic hydrops are believed to play a role. Although there is no certain treatment procedure for Ménière's disease, some treatments are applied to prevent attacks, to treat the symptoms that occur during the attacks, and to prevent the permanent effects of the symptoms on the hearing and balance system. Lifestyle changes, dietary modifications, diuretics, vasodilator corticosteroids, intratympanic steroids, surgical methods are some of these treatment methods. Dietary modification includes a low sodium diet, a reduction in daily alcohol and caffeine intake, a gluten-free diet, and a new dietary approach to specially processed grains, all of which are first-line treatments. The goal of this review article is to examine the relationship between MD and dietary intervention, which is frequently used in the prevention and treatment of MD attacks.

Could ionic regulation disorders explain the overlap between meniere's disease and migraine?

Ménière's disease (MD) is an inner ear disorder characterized by a burden of symptoms and comorbidities, including migraine. In both disorders, ionic dysregulation may play a role as a predisposing factor. In recent years. aquaporins have been widely investigated, but the results are far from conclusive. We recently studied the genetics of ionic transporters and the hormone endogenous ouabain as predisposing factors for development of MD. In particular, we found two genetic polymorphisms associated with MD: 1) rs3746951, a missense variant (Gly180Ser) in the salt-inducible kinase-1 (SIK1) gene encoding a Na+, K+ ATPase; 2) rs487119, an intronic variant of gene SLC8A1 coding for a Na+, Ca++ exchanger (NCX-1). Ionic concentration in the brain also plays a role in the pathophysiology of migraine. In this brief review we summarize what has been published on MD and migraine.

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.

MicroRNA Profiling as a Methodology to Diagnose Ménière's Disease: Potential Application of Machine Learning

OBJECTIVE

Diagnosis and treatment of Ménière's disease remains a significant challenge because of our inability to understand what is occurring on a molecular level. MicroRNA (miRNA) perilymph profiling is a safe methodology and may serve as a "liquid biopsy" equivalent. We used machine learning (ML) to evaluate miRNA expression profiles of various inner ear pathologies to predict diagnosis of Ménière's disease.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary academic hospital.

SUBJECTS AND METHODS

Perilymph was collected during labyrinthectomy (Ménière's disease, n = 5), stapedotomy (otosclerosis, n = 5), and cochlear implantation (sensorineural hearing loss [SNHL], n = 9). miRNA was isolated and analyzed with the Affymetrix miRNA 4.0 array. Various ML classification models were evaluated with an 80/20 train/test split and cross-validation. Permutation feature importance was performed to understand miRNAs that were critical to the classification models.

RESULTS

In terms of miRNA profiles for conductive hearing loss versus Ménière's, 4 models were able to differentiate and identify the 2 disease classes with 100% accuracy. The top-performing models used the same miRNAs in their decision classification model but with different weighted values. All candidate models for SNHL versus Ménière's performed significantly worse, with the best models achieving 66% accuracy. Ménière's models showed unique features distinct from SNHL.

CONCLUSIONS

We can use ML to build Ménière's-specific prediction models using miRNA profile alone. However, ML models were less accurate in predicting SNHL from Ménière's, likely from overlap of miRNA biomarkers. The power of this technique is that it identifies biomarkers without knowledge of the pathophysiology, potentially leading to identification of novel biomarkers and diagnostic tests.

Variations in the potassium voltage-gated channel subfamily E regulatory subunit 1 gene associated with noise-induced hearing loss in the Chinese population

Noise-induced hearing loss (NIHL) is one of the most common occupational health risks in industrialized countries. It has been recognized to result from interactions between genetic and environmental factors. This study investigated the influence of genetic mutations in the potassium voltage-gated channel subfamily E regulatory subunit 1 (KCNE1) gene on susceptibility to NIHL. A total of 2689 industrial workers in eastern China were recruited to participate. Three single-nucleotide polymorphisms (SNPs) of KCNE1 were genotyped in noise-exposed workers who were classified into 589 cases and 639 control individuals. Then, main effects of the genotypes and their interactions with environmental factors were evaluated. Results showed that the rs3453 C allele located in KCNE1 3'-UTR region and the rs1805127 G allele in the encoding region were associated with increased risk of NIHL in the Chinese population. There is an association between TAA, TAG, and other (CAA/CGA) haplotypes (rs3453-rs11702354-rs1805127) and increased risk of NIHL with OR = 1.33, 1.43, and 2.93 (P = 0.022, 0.017, and 0.001 respectively) compared with CGG group. Results also showed a significant interaction between rs3453, rs1805127, and high-temperature exposure (P = 0.0002, adjusted OR = 1.85). The cellular evidence indicated that polymorphisms rs3453 and rs1805127 may play key roles in hearing loss through affecting KCNE1 expressions by the way of microRNA and protein respectively. The further animal study is still needed to confirm these mechanisms. KCNE1 rs3453 and rs1805127 may have a potential as biomarkers for screening the susceptibility to NIHL.

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.

Expression of aquaporins in inner ear disease

The inner ear is responsible for hearing and balance and consists of a membranous labyrinth within a bony labyrinth. The balance structure is divided into the otolith organ that recognizes linear acceleration and the semicircular canal that is responsible for rotational movement. The cochlea is the hearing organ. The external and middle ear are covered with skin and mucosa, respectively, and the space is filled with air, whereas the inner ear is composed of endolymph and perilymph. The inner ear is a fluid-filled sensory organ composed of hair cells with cilia on the upper part of the cells that convert changes in sound energy and balance into electric energy through the hair cells to transmit signals to the auditory nerve through synapses. Aquaporins (AQPs) are a family of transmembrane proteins present in all species that can be roughly divided into three subfamilies according to structure and function: 1) classical AQP, 2) aquaglyceroporin, and 3) superaquaporin. Currently, the subfamily of mammalian species is known to include 13 AQP members (AQP0-AQP12). AQPs have a variety of functions depending on their structure and are related to inner ear diseases such as Meniere's disease, sensorineural hearing loss, and presbycusis. Additional studies on the relationship between the inner ear and AQPs may be helpful in the diagnosis and treatment of inner ear disease. Laryngoscope, 130:1532-1539, 2020.