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Long L, Tang Y. Association between sleep duration and hearing threshold shifts of adults in the United States: National Health and Nutrition Examination Survey, 2015-2016. BMC Public Health 2023; 23:2305. [PMID: 37990210 PMCID: PMC10664608 DOI: 10.1186/s12889-023-17204-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 11/10/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND Obstructive sleep apnea (OSA) is linked to hearing loss (HL). Another sleep characteristics, sleep duration might also be associated with HL, but prior evidence is limited. This study is aimed to investigate the association between sleep duration and hearing level in the adult US population. METHODS In total, a sample of 2777 individuals aged 20-69 years from the 2015-2016 National Health and Nutrition Examination Survey cycle (NHANES, 2015-2016) were investigated in this study. Self-reported sleep duration data was classified into the short-sleep (< 7 h), normal-sleep (7-9 h), and long-sleep (> 9 h) group. Multivariable linear regression models between sleep duration and hearing threshold shifts were estimated. Interactions between sleep duration and age, gender, race, OSA were also considered, and the study population was stratified by age, gender, race, and OSA to analyze the potential disparities among adults in different subgroups. RESULTS Long-sleep duration was positively associated with speech- and high-frequency pure-tone average (PTA) thresholds with statistical significance (β = 1.31, 95%CI: 0.10, 2.53, P = 0.0347, and β = 2.71, 95%CI: 0.69, 4.74, P = 0.0087, respectively). When stratified by age, short sleep duration was positively associated with low-, and speech-frequency PTAs (P = 0.0140 and 0.0225, respectively) for adults aged 40-59 years, and long-sleep duration was positively associated with low-, and speech-frequency PTAs (P = 0.0495 and 0.0142, respectively) for adults aged 60-69 years with statistical significance. There was statistically significant interaction between OSA and sleep duration on speech-frequency PTA, but no significant interaction between either gender or race with sleep duration on hearing thresholds among US adults. CONCLUSION Short/long sleep durations are associated with worse hearing level comparing to sleep 7-9 h in the American adults. Nonoptimal sleep duration may be a potential risk factor for HL.
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Affiliation(s)
- Lili Long
- Department of Otorhinolaryngology, Sichuan University Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Yuedi Tang
- Department of Otorhinolaryngology Head and Neck Surgery, West China Hospital of Sichuan University, No. 37 Guo-Xue-Xiang, Chengdu, 610041, Sichuan, China.
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Mom R, Réty S, Mocquet V, Auguin D. In silico pharmacological study of AQP2 inhibition by steroids contextualized to Ménière's disease treatments. Front Neurol 2023; 14:1270092. [PMID: 37928160 PMCID: PMC10620702 DOI: 10.3389/fneur.2023.1270092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/21/2023] [Indexed: 11/07/2023] Open
Abstract
Ménière's disease (MD) is characterized by an abnormal dilatation of the endolymphatic compartment called endolymphatic hydrops and is associated with fluctuating hearing losses and vertigo. Corticosteroid treatment is typically administered for its anti-inflammatory effects to MD patients. However, we recently described for the first time a direct interaction of two corticosteroids (dexamethasone and cortisol) with human AQP2 which strongly inhibited water fluxes. From these initial studies, we proposed an AQPs Corticosteroids Binding Site (ACBS). In the present work, we tested the interaction of 10 molecules associated to the steroid family for this putative ACBS. We observed a wide diversity of affinity and inhibitory potential of these molecules toward AQP2 and discussed the implications for inner ear physiology. Among the tested compounds, cholecalciferol, calcitriol and oestradiol were the most efficient AQP2 water permeability inhibitors.
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Affiliation(s)
- Robin Mom
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR 5239, INSERM U1293, Université Claude Bernard Lyon 1, Lyon, France
- Research Group on Vestibular Pathophysiology, CNRS, Unit GDR2074, Marseille, France
| | - Stéphane Réty
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR 5239, INSERM U1293, Université Claude Bernard Lyon 1, Lyon, France
| | - Vincent Mocquet
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR 5239, INSERM U1293, Université Claude Bernard Lyon 1, Lyon, France
| | - Daniel Auguin
- Laboratoire de Physiologie, Ecologie et Environnement (P2E), UPRES EA 1207/USC INRAE-1328, UFR Sciences et Techniques, Université d’Orléans, Orléans, France
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Zou J, Zhang G, Li H, Zhao Z, Zhang Q, Pyykkö I, Mäkitie A. Multiple genetic variants involved in both autoimmunity and autoinflammation detected in Chinese patients with sporadic Meniere's disease: a preliminary study. Front Neurol 2023; 14:1159658. [PMID: 37273692 PMCID: PMC10232973 DOI: 10.3389/fneur.2023.1159658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/20/2023] [Indexed: 06/06/2023] Open
Abstract
Background The mechanisms of Meniere's disease (MD) remain largely unknown. The purpose of this study was to identify possible genetic variants associated with immune regulation in MD. Methods The whole immune genome of 16 Chinese patients diagnosed with sporadic MD was sequenced using next-generation sequencing. Results Definite pathological variants of MEFV (c.1223G>A, c.1105C>T), COL7A1 (c.5287C>T), and ADA (c.445C>T) contributing to the clinical phenotype were found in three patients. Limited and likely pathological variants of TLR3 (c.2228G>A) and RAB27A (c.560G>A) were detected in one patient each. The following definite pathological variants impairing the structure and function of translated proteins were detected in 10 patients, and multigene variants occurred in five patients: PRF1 (c.710C>A), UNC13D (c.1228A>C), COLEC11 (c.169C>T), RAG2 (c.200G>C), BLM (c.1937G>T), RNF31 (c.2533G>A), FAT4 (c.11498A>G), PEPD (c.788A>G), TNFSF12 (c.470G>A), VPS13B (c.11972A>T), TNFRSF13B (c.226G>A), ERCC6L2 (c.4613A>G), TLR3 (c.2228G>A), ADA (c.445C>T), PEPD (c.151G>A), and MOGS (c.2470G>A). The following limited pathological variants impairing the structure and function of translated proteins were detected in five patients, with double gene variants identified in one patient: EXTL3 (c.1396G>A), MTHFD1 (c.2057G>A), FANCA (c.2039T>C), LPIN2 (c.1814C>T), NBAS (c.4049T>C), and FCN3 (c.734G>A). Conclusion Patients with sporadic MD carry multiple genetic variants involved in multiple steps of immune regulation, which might render patients susceptible to developing inflammation via both autoimmune and autoinflammation mechanisms upon internal stress.
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Affiliation(s)
- Jing Zou
- Department of Otolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China
- Research Program in Systems Oncology, Department of Otorhinolaryngology-Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Guoping Zhang
- Department of Otolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Hongbin Li
- Department of Otolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Zikai Zhao
- Department of Otolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Qing Zhang
- Department of Otolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Ilmari Pyykkö
- Hearing and Balance Research Unit, Field of Otolaryngology, School of Medicine, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Antti Mäkitie
- Research Program in Systems Oncology, Department of Otorhinolaryngology-Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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Huang C, Wang Q, Pan X, Li W, Liu W, Jiang W, Huang L, Peng A, Zhang Z. 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. Front Neurol 2022; 13:781031. [PMID: 35280304 PMCID: PMC8904419 DOI: 10.3389/fneur.2022.781031] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 01/27/2022] [Indexed: 12/20/2022] Open
Abstract
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.
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Affiliation(s)
- Chao Huang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Qin Wang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Xueying Pan
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wei Li
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wei Liu
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wenqi Jiang
- Department of Anesthesiology, Sun Yat-Sen University Cancer Center, Guangzhou, China
| | - Li Huang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Anquan Peng
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Zhiwen Zhang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
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Absence of Endolymphatic Sac Ion Transport Proteins in Large Vestibular Aqueduct Syndrome-A Human Temporal Bone Study. Otol Neurotol 2021; 41:e1256-e1263. [PMID: 32890293 DOI: 10.1097/mao.0000000000002832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Epithelial ion transport pathologies of the endolymphatic sac (ES) are associated with large vestibular aqueduct syndrome (LVAS). BACKGROUND LVAS is defined by the pathognomonic features of a widened bony vestibular aqueduct (VA) and an enlarged ES. The underlying cause of its associated cochleovestibular symptoms remains elusive. Disturbances in epithelial ion transport in the enlarged ES, affecting inner ear fluid regulation, were proposed as a possible pathophysiology. However, although respective epithelial ion transport pathologies have been demonstrated in the enlarged ES from transgenic LVAS mouse models, these pathologies have not been investigated in human LVAS cases. METHODS Histological and immunohistochemical analysis of the enlarged ES epithelium in postmortem temporal bones from two individuals with a clinical diagnosis of LVAS. RESULTS The enlarged ES epithelium demonstrated an overall atypical epithelial differentiation and a lack of the immunolocalization of signature ion transport proteins. Notably, in both cases, a rudimentary branch of the ES with a typically differentiated ES epithelium was present. CONCLUSIONS The described cellular and molecular pathologies of the enlarged ES in humans provide evidence of epithelial transport pathology as one potential cause of cochleovestibular symptoms in LVAS. The present findings also emphasize the clinical relevance of already established LVAS mouse models.
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Oğuz E, Cebeci A, Geçici CR. The relationship between nutrition and Ménière's disease. Auris Nasus Larynx 2021; 48:803-808. [PMID: 33773852 DOI: 10.1016/j.anl.2021.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/13/2021] [Accepted: 03/02/2021] [Indexed: 10/21/2022]
Abstract
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.
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Affiliation(s)
- Esma Oğuz
- Department of Nutrition and Dietetics, Institute of Health Sciences, Marmara University, Istanbul, Turkey
| | - Aybike Cebeci
- Department of Nutrition and Dietetics, Institute of Health Sciences, Marmara University, Istanbul, Turkey
| | - Cennet Reyyan Geçici
- Department of Audiology, Faculty of Health Sciences, Marmara University, Istanbul, Turkey.
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Chabbert C. Pathophysiological mechanisms at the sources of the endolymphatic hydrops, and possible consequences. J Vestib Res 2021; 31:289-295. [PMID: 33579885 DOI: 10.3233/ves-200792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The mechanisms of ion exchanges and water fluxes underlying the endolymphatic hydrops phenomenon, remain indeterminate so far. This review intends to reposition the physical environment of the endolymphatic compartment within the inner ear, as well as to recall the molecular effectors present in the membranous labyrinth and that could be at the source of the hydrops.
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Affiliation(s)
- Christian Chabbert
- Aix Marseille University-CNRS, Laboratory of Cognitive Neurosciences, UMR 7291, Team Pathophysiology and Therapy of Vestibular Disorders, Marseille, France.,Research Group on Vestibular Pathophysiology Unity GDR#, France
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8
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“Reversed polarization” of Na/K-ATPase—a sign of inverted transport in the human endolymphatic sac: a super-resolution structured illumination microscopy (SR-SIM) study. Cell Tissue Res 2019; 379:445-457. [DOI: 10.1007/s00441-019-03106-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 09/15/2019] [Indexed: 02/06/2023]
Abstract
AbstractThe human endolymphatic sac (ES) is believed to regulate inner ear fluid homeostasis and to be associated with Meniere’s disease (MD). We analyzed the ion transport protein sodium/potassium-ATPase (Na/K-ATPase) and its isoforms in the human ES using super-resolution structured illumination microscopy (SR-SIM). Human vestibular aqueducts were collected during trans-labyrinthine vestibular schwannoma surgery after obtaining ethical permission. Antibodies against various isoforms of Na/K-ATPase and additional solute-transporting proteins, believed to be essential for ion and fluid transport, were used for immunohistochemistry. A population of epithelial cells of the human ES strongly expressed Na/K-ATPase α1, β1, and β3 subunit isoforms in either the lateral/basolateral or apical plasma membrane domains. The β1 isoform was expressed in the lateral/basolateral plasma membranes in mostly large cylindrical cells, while β3 and α1 both were expressed with “reversed polarity” in the apical cell membrane in lower epithelial cells. The heterogeneous expression of Na/K-ATPase subunits substantiates earlier notions that the ES is a dynamic structure where epithelial cells show inverted epithelial transport. Dual absorption and secretion processes may regulate and maintain inner ear fluid homeostasis. These findings may shed new light on the etiology of endolymphatic hydrops and MD.
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Kim SH, Nam GS, Choi JY. Pathophysiologic Findings in the Human Endolymphatic Sac in Endolymphatic Hydrops: Functional and Molecular Evidence. Ann Otol Rhinol Laryngol 2019; 128:76S-83S. [PMID: 31092029 DOI: 10.1177/0003489419837993] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
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.
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Affiliation(s)
- Sung Huhn Kim
- 1 Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Republic of Korea.,2 The Airway Mucus Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Gi-Sung Nam
- 1 Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jae Young Choi
- 1 Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Republic of Korea.,2 The Airway Mucus Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
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Effect of sleep deprivation on hearing levels in rats. Int J Pediatr Otorhinolaryngol 2018; 112:169-175. [PMID: 30055728 DOI: 10.1016/j.ijporl.2018.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/03/2018] [Accepted: 07/04/2018] [Indexed: 11/20/2022]
Abstract
OBJECTIVES To our knowledge, the influence of sleep deprivation on hearing levels has yet to be assessed in animals. Therefore, we evaluated whether auditory function was affected by sleep deprivation in rats. METHODS Male Wistar rats (aged 9 weeks, weighing 300-400 g) were used for the study and were randomly assigned to a control (n = 15) or sleep deprivation group (n = 12). Hearing levels were evaluated at baseline and 9 days after sleep deprivation using auditory evoked brainstem responses (ABRs) and distortion product otoacoustic emission (DPOAE) measurements. Blood was collected for the measurement of interleukin-1β and corticosterone levels. RESULTS The ABR thresholds (at 8, 16, and 32 kHz) at 9 days were significantly elevated in the sleep deprivation group compared to the control group (p < 0.05, respectively). The sleep deprivation group showed a defect in the function of outer hair cells, as evidenced by decreased levels of distortion product otoacoustic emission. IL-1β was significantly increased in the sleep deprivation group. Sleep-deprived rats exhibited rupture of Reissner's membrane and morphological damage to stereocilia. CONCLUSION These results suggest that sleep deprivation induces damage to the cochlea and results in hearing loss in Wistar rats.
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11
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Honda K, Kim SH, Kelly MC, Burns JC, Constance L, Li X, Zhou F, Hoa M, Kelley MW, Wangemann P, Morell RJ, Griffith AJ. Molecular architecture underlying fluid absorption by the developing inner ear. eLife 2017; 6. [PMID: 28994389 PMCID: PMC5634787 DOI: 10.7554/elife.26851] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 09/10/2017] [Indexed: 12/26/2022] Open
Abstract
Mutations of SLC26A4 are a common cause of hearing loss associated with enlargement of the endolymphatic sac (EES). Slc26a4 expression in the developing mouse endolymphatic sac is required for acquisition of normal inner ear structure and function. Here, we show that the mouse endolymphatic sac absorbs fluid in an SLC26A4-dependent fashion. Fluid absorption was sensitive to ouabain and gadolinium but insensitive to benzamil, bafilomycin and S3226. Single-cell RNA-seq analysis of pre- and postnatal endolymphatic sacs demonstrates two types of differentiated cells. Early ribosome-rich cells (RRCs) have a transcriptomic signature suggesting expression and secretion of extracellular proteins, while mature RRCs express genes implicated in innate immunity. The transcriptomic signature of mitochondria-rich cells (MRCs) indicates that they mediate vectorial ion transport. We propose a molecular mechanism for resorption of NaCl by MRCs during development, and conclude that disruption of this mechanism is the root cause of hearing loss associated with EES.
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Affiliation(s)
- Keiji Honda
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Sung Huhn Kim
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Michael C Kelly
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Joseph C Burns
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Laura Constance
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Xiangming Li
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Fei Zhou
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Michael Hoa
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Matthew W Kelley
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Philine Wangemann
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Robert J Morell
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Andrew J Griffith
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
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Runggaldier D, Pradas LG, Neckel PH, Mack AF, Hirt B, Gleiser C. Claudin expression in the rat endolymphatic duct and sac - first insights into regulation of the paracellular barrier by vasopressin. Sci Rep 2017; 7:45482. [PMID: 28374851 PMCID: PMC5379655 DOI: 10.1038/srep45482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/28/2017] [Indexed: 12/13/2022] Open
Abstract
Hearing and balance functions of the inner ear rely on the homeostasis of the endolymphatic fluid. When disturbed, pathologic endolymphatic hydrops evolves as observed in Menière’s disease. The molecular basis of inner ear fluid regulation across the endolymphatic epithelium is largely unknown. In this study we identified the specific expression of the tight junction (TJ) molecules Claudin 3, 4, 6, 7, 8, 10, and 16 in epithelial preparations of the rat inner ear endolymphatic duct (ED) and endolymphatic sac (ES) by high-throughput qPCR and immunofluorescence confocal microscopy. Further we showed that Claudin 4 in the ES is a target of arginine-vasopressin (AVP), a hormone elevated in Menière’s disease. Moreover, our transmission-electron microscopy (TEM) analysis revealed that the TJs of the ED were shallow and shorter compared to the TJ of the ES indicating facilitation of a paracellular fluid transport across the ED epithelium. The significant differences in the subcellular localization of the barrier-forming protein Claudin 3 between the ED and ES epithelium further support the TEM observations. Our results indicate a high relevance of Claudin 3 and Claudin 4 as important paracellular barrier molecules in the ED and ES epithelium with potential involvement in the pathophysiology of Menière’s disease.
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Affiliation(s)
- Daniel Runggaldier
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Lidia Garcia Pradas
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Peter H Neckel
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Andreas F Mack
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Bernhard Hirt
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Corinna Gleiser
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
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Møller MN, Kirkeby S, Vikeså J, Nielsen FC, Cayé-Thomasen P. The human endolymphatic sac expresses natriuretic peptides. Laryngoscope 2017; 127:E201-E208. [DOI: 10.1002/lary.26074] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/07/2016] [Accepted: 04/12/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Martin Nue Møller
- Department of Otorhinolaryngology, Head and Neck Surgery; Rigshospitalet; Copenhagen Denmark
| | - Svend Kirkeby
- Department of Oral Medicine, Dental School, Panum Institute; University of Copenhagen; Copenhagen Denmark
| | - Jonas Vikeså
- Center for Genomic Medicine; University of Copenhagen; Rigshospitalet Copenhagen Denmark
| | - Finn Cilius Nielsen
- Center for Genomic Medicine; University of Copenhagen; Rigshospitalet Copenhagen Denmark
| | - Per Cayé-Thomasen
- Department of Otorhinolaryngology, Head and Neck Surgery; Rigshospitalet; Copenhagen Denmark
- Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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Miyashita T, Inamoto R, Fukuda S, Hoshikawa H, Hitomi H, Kiyomoto H, Nishiyama A, Mori N. Hormonal changes following a low-salt diet in patients with Ménière's disease. Auris Nasus Larynx 2017; 44:52-57. [DOI: 10.1016/j.anl.2016.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/14/2016] [Accepted: 03/07/2016] [Indexed: 12/18/2022]
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Teggi R, Zagato L, Delli Carpini S, Citterio L, Cassandro C, Albera R, Yang WY, Staessen JA, Bussi M, Manunta P, Lanzani C. Genetics of ion homeostasis in Ménière's Disease. Eur Arch Otorhinolaryngol 2016; 274:757-763. [PMID: 27837419 DOI: 10.1007/s00405-016-4375-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/04/2016] [Indexed: 01/07/2023]
Abstract
Aim of this work was to assess the role of polymorphisms belonging to genes involved in the regulation of ionic homeostasis in Caucasian patients with Ménière Disease (MD). We recruited 155 patients with definite Ménière Disease and 186 controls (Control Group 1) without a lifetime history of vertigo, overlapping with patients for age and rate of hypertension. We validated the positive results on 413 Caucasian subjects selected from a European general population (Control Group 2). The clinical history for migraine and hypertension was collected; genomic DNA was characterized for a panel of 33 SNPs encoding proteins involved in ionic transport. We found a higher rate of migraineurs in MD subjects compared to Group 1 (46.8 vs 15.5%, p = 0.00005). Four SNPs displayed differences in MD patients compared to Group 1 controls: rs3746951 and rs2838301 in SIK1 gene, rs434082 and rs487119 in SLC8A1; the p values of Chi-squared test for genotype frequencies are 0.009, 0.023, 0.009 and 0.048, respectively. SLC8A1 gene encodes for Na+-Ca++ exchanger, while SIK1 gene encodes for Salt Inducible Kinase 1, an enzyme associated with Na+-K+ ATPase function. The validation with Control Group 2 displayed that only rs3746951 and rs487119 are strongly associated to MD (p = 0.001 and p = 0.0004, respectively). These data support the hypothesis that a genetically induced dysfunction of ionic transport may act as a predisposing factors to develop MD.
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Affiliation(s)
- Roberto Teggi
- ENT Division, Department of ENT, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy.
| | - Laura Zagato
- Genomics of Renal Diseases and Hypertension Unit, Division of Genetics and Cellular Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Simona Delli Carpini
- Genomics of Renal Diseases and Hypertension Unit, Division of Genetics and Cellular Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Lorena Citterio
- Genomics of Renal Diseases and Hypertension Unit, Division of Genetics and Cellular Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Roberto Albera
- Surgical Sciences Department, University of Turin, Turin, Italy
| | - Wen-Yi Yang
- Studies Coordinating Centre, Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven, Louvain, Belgium
| | - Jan A Staessen
- Studies Coordinating Centre, Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven, Louvain, Belgium
| | - Mario Bussi
- ENT Division, Department of ENT, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Paolo Manunta
- Genomics of Renal Diseases and Hypertension Unit, Division of Genetics and Cellular Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy.,Chair of Nephrology, Vita-Salute San Raffaele University, Milan, Italy
| | - Chiara Lanzani
- Genomics of Renal Diseases and Hypertension Unit, Division of Genetics and Cellular Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy.,Chair of Nephrology, Vita-Salute San Raffaele University, Milan, Italy
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Ion transport its regulation in the endolymphatic sac: suggestions for clinical aspects of Meniere's disease. Eur Arch Otorhinolaryngol 2016; 274:1813-1820. [PMID: 27804084 PMCID: PMC5340852 DOI: 10.1007/s00405-016-4362-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 10/26/2016] [Indexed: 01/22/2023]
Abstract
Ion transport and its regulation in the endolymphatic sac (ES) are reviewed on the basis of recent lines of evidence. The morphological and physiological findings demonstrate that epithelial cells in the intermediate portion of the ES are more functional in ion transport than those in the other portions. Several ion channels, ion transporters, ion exchangers, and so on have been reported to be present in epithelial cells of ES intermediate portion. An imaging study has shown that mitochondria-rich cells in the ES intermediate portion have a higher activity of Na+, K+-ATPase and a higher Na+ permeability than other type of cells, implying that molecules related to Na+ transport, such as epithelial sodium channel (ENaC), Na+–K+–2Cl− cotransporter 2 (NKCC2) and thiazide-sensitive Na+–Cl− cotransporter (NCC), may be present in mitochondria-rich cells. Accumulated lines of evidence suggests that Na+ transport is most important in the ES, and that mitochondria-rich cells play crucial roles in Na+ transport in the ES. Several lines of evidence support the hypothesis that aldosterone may regulate Na+ transport in ES, resulting in endolymph volume regulation. The presence of molecules related to acid/base transport, such as H+-ATPase, Na+–H+ exchanger (NHE), pendrin (SLC26A4), Cl−–HCO3− exchanger (SLC4A2), and carbonic anhydrase in ES epithelial cells, suggests that acid/base transport is another important one in the ES. Recent basic and clinical studies suggest that aldosterone may be involved in the effect of salt-reduced diet treatment in Meniere’s disease.
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Kumarhia D, He L, McCluskey LP. Inflammatory stimuli acutely modulate peripheral taste function. J Neurophysiol 2016; 115:2964-75. [PMID: 27009163 DOI: 10.1152/jn.01104.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/23/2016] [Indexed: 12/30/2022] Open
Abstract
Inflammation-mediated changes in taste perception can affect health outcomes in patients, but little is known about the underlying mechanisms. In the present work, we hypothesized that proinflammatory cytokines directly modulate Na(+) transport in taste buds. To test this, we measured acute changes in Na(+) flux in polarized fungiform taste buds loaded with a Na(+) indicator dye. IL-1β elicited an amiloride-sensitive increase in Na(+) transport in taste buds. In contrast, TNF-α dramatically and reversibly decreased Na(+) flux in polarized taste buds via amiloride-sensitive and amiloride-insensitive Na(+) transport systems. The speed and partial amiloride sensitivity of these changes in Na(+) flux indicate that IL-1β and TNF-α modulate epithelial Na(+) channel (ENaC) function. A portion of the TNF-mediated decrease in Na(+) flux is also blocked by the TRPV1 antagonist capsazepine, although TNF-α further reduced Na(+) transport independently of both amiloride and capsazepine. We also assessed taste function in vivo in a model of infection and inflammation that elevates these and additional cytokines. In rats administered systemic lipopolysaccharide (LPS), CT responses to Na(+) were significantly elevated between 1 and 2 h after LPS treatment. Low, normally preferred concentrations of NaCl and sodium acetate elicited high response magnitudes. Consistent with this outcome, codelivery of IL-1β and TNF-α enhanced Na(+) flux in polarized taste buds. These results demonstrate that inflammation elicits swift changes in Na(+) taste function, which may limit salt consumption during illness.
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Affiliation(s)
- Devaki Kumarhia
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia; and Graduate Program in Molecular Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Lianying He
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia; and
| | - Lynnette Phillips McCluskey
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia; and
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Matsubara A, Miyashita T, Inamoto R, Hoshikawa H, Mori N. Cystic fibrosis transmembrane conductance regulator in the endolymphatic sac of the rat. Auris Nasus Larynx 2014; 41:409-12. [PMID: 24598307 DOI: 10.1016/j.anl.2014.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Na(+) and Cl(-) are dominant ions in the endolymphatic fluid in the endolymphatic sac and are important for volume regulation in the endolymphatic sac. An epithelial sodium channel (ENaC) and other Na(+) transporters have been identified in the endolymphatic sac epithelia, and they are involved in the regulation of endolymph. Although the presence of Cl(-) channels in the endolymphatic sac epithelia has been speculated, no Cl(-) channels have been identified. In this study, we confirmed the expression of cystic fibrosis transmembrane conductance regulator (CFTR) in the endolymphatic sac by reverse transcriptase polymerase chain reaction (RT-PCR) and by immunohistochemical staining. METHODS Pure mRNA from endolymphatic sac epithelia was prepared using laser capture microdissection (LCM) and examined using RT-PCR. Localization of CFTR and ENaC in the endolymphatic sac was examined using immunohistochemistry. RESULTS mRNA of the CFTR was expressed in the endolymphatic sac. Immunohistochemical analysis showed the expression of the CFTR on apical side of the endolymphatic sac epithelia and co-localization with the ENaC. CONCLUSION RT-PCR and immunohistochemistry were used to identify the expression of CFTR in the endolymphatic sac epithelia, which gives us a clue for understanding Cl(-) transport in the endolymphatic sac. These results suggest a pathway for Cl(-), possibly through interaction with the ENaC, which may regulate the endolymph in the endolymphatic sac.
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Affiliation(s)
- Ai Matsubara
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Japan.
| | - Takenori Miyashita
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Japan
| | - Ryuhei Inamoto
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Japan
| | - Hiroshi Hoshikawa
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Japan
| | - Nozomu Mori
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Japan
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Li X, Zhou F, Marcus DC, Wangemann P. Endolymphatic Na⁺ and K⁺ concentrations during cochlear growth and enlargement in mice lacking Slc26a4/pendrin. PLoS One 2013; 8:e65977. [PMID: 23741519 PMCID: PMC3669272 DOI: 10.1371/journal.pone.0065977] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 05/01/2013] [Indexed: 11/30/2022] Open
Abstract
Slc26a4 (Δ/Δ) mice are deaf, develop an enlarged membranous labyrinth, and thereby largely resemble the human phenotype where mutations of SLC26A4 cause an enlarged vestibular aqueduct and sensorineural hearing loss. The enlargement is likely caused by abnormal ion and fluid transport during the time of embryonic development, however, neither the mechanisms of ion transport nor the ionic composition of the luminal fluid during this time of development are known. Here we determine the ionic composition of inner ear fluids at the time at which the enlargement develops and the onset of expression of selected ion transporters. Concentrations of Na(+) and K(+) were measured with double-barreled ion-selective electrodes in the cochlea and the endolymphatic sac of Slc26a4 (Δ/+), which develop normal hearing, and of Slc26a4 (Δ/Δ) mice, which fail to develop hearing. The expression of specific ion transporters was examined by quantitative RT-PCR and immunohistochemistry. High Na(+) (∼141 mM) and low K(+) concentrations (∼11 mM) were found at embryonic day (E) 16.5 in cochlear endolymph of Slc26a4 (Δ/+) and Slc26a4 (Δ/Δ) mice. Shortly before birth the K(+) concentration began to rise. Immediately after birth (postnatal day 0), the Na(+) and K(+) concentrations in cochlear endolymph were each ∼80 mM. In Slc26a4 (Δ/Δ) mice, the rise in the K(+) concentration occurred with a ∼3 day delay. K(+) concentrations were also found to be low (∼15 mM) in the embryonic endolymphatic sac. The onset of expression of the K(+) channel KCNQ1 and the Na(+)/2Cl(-)/K(+) cotransporter SLC12A2 occurred in the cochlea at E19.5 in Slc26a4 (Δ/+) and Slc26a4 (Δ/Δ) mice. These data demonstrate that endolymph, at the time at which the enlargement develops, is a Na(+)-rich fluid, which transitions into a K(+)-rich fluid before birth. The data suggest that the endolymphatic enlargement caused by a loss of Slc26a4 is a consequence of disrupted Na(+) transport.
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Affiliation(s)
- Xiangming Li
- Anatomy and Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
| | - Fei Zhou
- Anatomy and Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
| | - Daniel C. Marcus
- Anatomy and Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
| | - Philine Wangemann
- Anatomy and Physiology Department, Kansas State University, Manhattan, Kansas, United States of America
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Abstract
HYPOTHESIS Pendrin acts as a Cl-/HCO3- exchanger and is responsible for endolymphatic fluid volume and pH homeostasis in human endolymphatic sac epithelial cells. BACKGROUND The endolymphatic sac (ES) is part of the membranous labyrinth in the inner ear that plays an important role in maintaining homeostasis of the endolymphatic fluid system. However, the exact mechanism of fluid volume and pH regulation is not fully understood yet. We aimed to demonstrate the expression of various anion exchangers (AEs), including pendrin, in cultured human endolymphatic sac epithelial (HESE) cells. METHODS Endolymphatic sac specimens were harvested during acoustic neuroma surgery (n = 24) using the translabyrinthine approach and then subcultured with high epidermal growth factor (EGF) (25 ng/ml) media and differentiated using low-EGF (0.5 ng/ml) media. The cultured cells were classified according to the morphology on TEM. The Cl-/HCO3- exchanger activity was assessed by pHi measurement using pH sensitive dye 2', 7'-bis (2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF/AM). We performed reverse transcriptase-polymerase chain reaction and immunohistochemical staining for AEs. RESULTS We determined that 7.3 ± 6.7% of cells differentiated into mitochodria-rich cells and 50.2 ± 15.1 of cells differentiated into ribosome-rich cells. bAE3, AE4, SLC26A4, SLC26A6, and SLC26A11 were also expressed in cultured HESE cells. The cultured cells had Cl-/HCO3- and Cl-/formate exchange activity on the luminal membrane, which is sensitive to anion channel inhibitors (DIDS 500 μM). Furthermore, we showed that pendrin (SLC26A4) was expressed in cultured HESE cell membranes. CONCLUSION Our results suggest that AEs, including pendrin, are expressed in epithelia of ES and may have role in maintaining ionic homeostasis, and the HESE culture system are useful for uncovering the functional role of ES epithelial cells.
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Water channel proteins in the inner ear and their link to hearing impairment and deafness. Mol Aspects Med 2012; 33:612-37. [DOI: 10.1016/j.mam.2012.06.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/11/2012] [Accepted: 06/17/2012] [Indexed: 11/24/2022]
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Current World Literature. Curr Opin Nephrol Hypertens 2011; 20:561-7. [DOI: 10.1097/mnh.0b013e32834a3de5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kim SH, Marcus DC. Regulation of sodium transport in the inner ear. Hear Res 2011; 280:21-9. [PMID: 21620939 DOI: 10.1016/j.heares.2011.05.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 04/27/2011] [Accepted: 05/02/2011] [Indexed: 12/31/2022]
Abstract
Na(+) concentrations in endolymph must be controlled to maintain hair cell function since the transduction channels of hair cells are cation-permeable, but not K(+)-selective. Flooding or fluctuations of the hair cell cytosol with Na(+) would be expected to lead to cellular dysfunction, hearing loss and vertigo. This review briefly describes cellular mechanisms known to be responsible for Na(+) homeostasis in each compartment of the inner ear, including the cochlea, saccule, semicircular canals and endolymphatic sac. The influx of Na(+) into endolymph of each of the organs is likely via passive diffusion, but these pathways have not yet been identified or characterized. Na(+) absorption is controlled by gate-keeper channels in the apical (endolymphatic) membrane of the transporting cells. Highly Na(+)-selective epithelial sodium channels (ENaCs) control absorption by Reissner's membrane, saccular extramacular epithelium, semicircular canal duct epithelium and endolymphatic sac. ENaC activity is controlled by a number of signal pathways, but most notably by genomic regulation of channel numbers in the membrane via glucocorticoid signaling. Non-selective cation channels in the apical membrane of outer sulcus epithelial cells and vestibular transitional cells mediate Na(+) and parasensory K(+) absorption. The K(+)-mediated transduction current in hair cells is also accompanied by a Na(+) flux since the transduction channels are non-selective cation channels. Cation absorption by all of these cells is regulated by extracellular ATP via apical non-selective cation channels (P2X receptors). The heterogeneous population of epithelial cells in the endolymphatic sac is thought to have multiple absorptive pathways for Na(+) with regulatory pathways that include glucocorticoids and purinergic agonists.
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Affiliation(s)
- Sung Huhn Kim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea
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Abstract
PURPOSE OF REVIEW To describe ion and water homeostatic mechanisms in the inner ear, how they are compromised in hearing disorders, and what treatments are employed to restore auditory function. RECENT FINDINGS The ion and water transport functions in the inner ear help maintain the proper endolymph K concentration required for hair cell function. Gene defects and idiopathic alterations in these transport functions cause hearing loss, but often the underlying cause is unknown. Current therapies largely involve glucocorticoid treatment, although the mechanisms of restoration are often undeterminable. Recent studies of these ion homeostatic functions in the ear are characterizing their cellular and molecular control. It is anticipated that future management of these hearing disorders will be more targeted to the cellular processes involved and improve the likelihood of hearing recovery. SUMMARY A better understanding of the ion homeostatic processes in the ear will permit more effective management of their associated hearing disorders. Sufficient insight into many homeostatic hearing disorders has now been attained to usher in a new era of better therapies and improved clinical outcomes.
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Affiliation(s)
- Dennis R Trune
- Oregon Hearing Research Center, Department of Otolaryngology Head Neck Surgery, Oregon Health & Science University, Portland, Oregon 97239-3098, USA.
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Current Opinion in Otolaryngology & Head and Neck Surgery. Current world literature. Curr Opin Otolaryngol Head Neck Surg 2010; 18:466-74. [PMID: 20827086 DOI: 10.1097/moo.0b013e32833f3865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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