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Salam SA, Mostafa F, Alnamshan MM, Elshewemi SS, Sorour JM. Thymoquinone ameliorates age-related hearing loss in C57BL/6J mice by modulating Sirt1 activity and Bak1 expression. Biomed Pharmacother 2021; 143:112149. [PMID: 34507120 DOI: 10.1016/j.biopha.2021.112149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/27/2021] [Accepted: 08/31/2021] [Indexed: 01/10/2023] Open
Abstract
Age-related hearing loss (AHL) is the most common sensory disorder of aged population. Currently, one of the most important sources of experimental medicine for AHL is medicinal plants. This study performed the first investigation of the effect of thymoquinone (TQ), a potent antioxidant, on AHL. Here, we used inbred C57BL/6J mice (B6 mice) as a successful experimental model of the early onset of AHL. The behavioral assessment of hearing revealed that the injection of a high dose of TQ (40 mg/kg; TQ40) significantly improved the auditory sensitivity of B6 mice at all tested frequencies (8, 16 and 22 kHz). Histological sections of cochlea from B6 mice injected with a low dose (20 mg/kg; TQ20) and high dose showed relatively less degenerative signs in the modiolus, hair cells and spiral ligaments, the main constituents of the cochlea. In addition, TQ40 completely restored the normal pattern of hair cells in B6 mice, as shown in scanning electron micrographs. Our data indicated that TQ20 and TQ40 reduced levels of Bak1-mediated apoptosis in the cochlea of B6 mice. Interestingly, the level of Sirt1, a positive regulator of autophagy, was significantly increased in B6 mice administered TQ40. In conclusion, TQ relieves the symptoms of AHL by downregulating Bak1 and activating Sirt1 in the cochlea of B6 mice.
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Affiliation(s)
- Sherine Abdel Salam
- Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt.
| | - Fatma Mostafa
- Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt.
| | - Mashael M Alnamshan
- Department of Biology, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia.
| | - Salma S Elshewemi
- Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt.
| | - Jehan M Sorour
- Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt.
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Siu JM, Negandhi J, Harrison RV, Wolter NE, James A. Ultrasonic bone removal from the ossicular chain affects cochlear structure and function. J Otolaryngol Head Neck Surg 2021; 50:23. [PMID: 33810814 PMCID: PMC8017701 DOI: 10.1186/s40463-021-00491-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/11/2021] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Ultrasonic bone removal devices (UBD) are capable of cutting through bony tissue without injury to adjacent soft tissue. The feasibility and safety of using this technology for removal of bone from an intact ossicular chain (as might be required for otosclerosis or congenital fixation) was investigated in an animal model. METHODS This was a prospective animal study conducted on seven anesthetised adult chinchillas. An UBD was used to remove bone from the malleus head in situ. Pre and post-operative distortion product otoacoustic emission (DPOAE) levels and auditory brainstem response (ABR) thresholds were recorded. Scanning electron microscopy (SEM) was used to assess cochlear haircell integrity. RESULTS Precise removal of a small quantity of bone from the malleus head was achieved by a 30s application of UBD without disruption of the ossicular chain or tympanic membrane. DPOAEs became undetectable after the intervention with signal-to-noise ratios (SNR) < 5 dB SPL in all ears. Furthermore, ABR thresholds were elevated > 85 dB SPL in 13 ears. SEM showed significant disruption of structural integrity of the organ of Corti, specifically loss and damage of outer haircells. CONCLUSIONS Although UBD can be used to reshape an ossicle without middle ear injury, prolonged contact with the ossicular chain can cause structural and functional injury to the cochlea. Extensive cochlea pathology was found, but we did not investigate for recovery from any temporary threshold shift. In the authors' opinion, further study should be undertaken before consideration is given to use of the device for release of ossicular fixation.
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Affiliation(s)
- Jennifer M Siu
- Department of Otolaryngology - Head & Neck Surgery, University of Toronto, Toronto, Canada
| | - Jaina Negandhi
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada
| | - Robert V Harrison
- Department of Otolaryngology - Head & Neck Surgery, University of Toronto, Toronto, Canada
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada
- Department of Otolaryngology, Hospital for Sick Children, University of Toronto, 555 University Avenue, Room 6133, Burton Wing, Toronto, ON, M5G 1X8, Canada
| | - Nikolaus E Wolter
- Department of Otolaryngology - Head & Neck Surgery, University of Toronto, Toronto, Canada
- Department of Otolaryngology, Hospital for Sick Children, University of Toronto, 555 University Avenue, Room 6133, Burton Wing, Toronto, ON, M5G 1X8, Canada
| | - Adrian James
- Department of Otolaryngology - Head & Neck Surgery, University of Toronto, Toronto, Canada.
- Department of Otolaryngology, Hospital for Sick Children, University of Toronto, 555 University Avenue, Room 6133, Burton Wing, Toronto, ON, M5G 1X8, Canada.
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Girdlestone CD, Ng J, Kössl M, Caplot A, Shadwick RE, Morell M. Correlating Cochlear Morphometrics from Parnell's Mustached Bat (Pteronotus parnellii) with Hearing. J Assoc Res Otolaryngol 2020; 21:425-444. [PMID: 32909111 DOI: 10.1007/s10162-020-00764-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 07/24/2020] [Indexed: 11/26/2022] Open
Abstract
Morphometric analysis of the inner ear of mammals can provide information for cochlear frequency mapping, a species-specific designation of locations in the cochlea at which different sound frequencies are encoded. Morphometric variation occurs in the hair cells of the organ of Corti along the cochlea, with the base encoding the highest frequency sounds and the apex encoding the lowest frequencies. Changes in cell shape and spacing can yield additional information about the biophysical basis of cochlear tuning mechanisms. Here, we investigate how morphometric analysis of hair cells in mammals can be used to predict the relationship between frequency and cochlear location. We used linear and geometric morphometrics to analyze scanning electron micrographs of the hair cells of the cochleae in Parnell's mustached bat (Pteronotus parnellii) and Wistar rat (Rattus norvegicus) and determined a relationship between cochlear morphometrics and their frequency map. Sixteen of twenty-two of the morphometric parameters analyzed showed a significant change along the cochlea, including the distance between the rows of hair cells, outer hair cell width, and gap width between hair cells. A multiple linear regression model revealed that nine of these parameters are responsible for 86.9 % of the variation in these morphometric data. Determining the most biologically relevant measurements related to frequency detection can give us a greater understanding of the essential biomechanical characteristics for frequency selectivity during sound transduction in a diversity of animals.
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Affiliation(s)
| | - Jodie Ng
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Manfred Kössl
- Institute for Cell Biology and Neuroscience, Goethe University, Max-von-Laue Str.13, 60438, Frankfurt/Main, Germany
| | - Adrien Caplot
- INSERM-UMR 1051, Institute for Neurosciences of Montpellier, 34091, Montpellier, France
| | - Robert E Shadwick
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Maria Morell
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- INSERM-UMR 1051, Institute for Neurosciences of Montpellier, 34091, Montpellier, France
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761, Bsum, Germany
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Mei X, Glueckert R, Schrott-Fischer A, Li H, Ladak HM, Agrawal SK, Rask-Andersen H. Vascular Supply of the Human Spiral Ganglion: Novel Three-Dimensional Analysis Using Synchrotron Phase-Contrast Imaging and Histology. Sci Rep 2020; 10:5877. [PMID: 32245997 PMCID: PMC7125215 DOI: 10.1038/s41598-020-62653-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/27/2020] [Indexed: 12/24/2022] Open
Abstract
Human spiral ganglion (HSG) cell bodies located in the bony cochlea depend on a rich vascular supply to maintain excitability. These neurons are targeted by cochlear implantation (CI) to treat deafness, and their viability is critical to ensure successful clinical outcomes. The blood supply of the HSG is difficult to study due to its helical structure and encasement in hard bone. The objective of this study was to present the first three-dimensional (3D) reconstruction and analysis of the HSG blood supply using synchrotron radiation phase-contrast imaging (SR-PCI) in combination with histological analyses of archival human cochlear sections. Twenty-six human temporal bones underwent SR-PCI. Data were processed using volume-rendering software, and a representative three-dimensional (3D) model was created to allow visualization of the vascular anatomy. Histologic analysis was used to verify the segmentations. Results revealed that the HSG is supplied by radial vascular twigs which are separate from the rest of the inner ear and encased in bone. Unlike with most organs, the arteries and veins in the human cochlea do not follow the same conduits. There is a dual venous outflow and a modiolar arterial supply. This organization may explain why the HSG may endure even in cases of advanced cochlear pathology.
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Grants
- the Sanming Project of Medicine in Shenzhen, China [SZSM201612076]
- Innsbruck University
- This study was supported by the Swedish Research Council [2017-03801], ALF grants from the Uppsala University Hospital, the Tysta Skolan Foundation, the Swedish Hearing Research Foundation, generous private funds from
- Natural Sciences and Engineering Research Council of Canada, the National Research Council Canada, the Canadian Institutes of Health Research, the Government of Saskatchewan, Western Economic Diversification Canada, and the University of Saskatchewan.
- This study was supported by the Swedish Research Council [2017-03801], ALF grants from the Uppsala University Hospital, the Tysta Skolan Foundation, the Swedish Hearing Research Foundation, generous private funds from Börje Runögård, Sweden, and the Sanming Project of Medicine in Shenzhen, China [SZSM201612076]. This work was made in collaboration with MED-EL Medical Electronics, R&D, GmbH, Innsbruck, Austria. Part of the research described in this paper was conducted at the BioMedical Imaging and Therapy (BMIT) facility at the Canadian Light Source Inc., which is funded by the Canada Foundation for Innovation, the Natural Sciences and Engineering Research Council of Canada, the National Research Council Canada, the Canadian Institutes of Health Research, the Government of Saskatchewan, Western Economic Diversification Canada, and the University of Saskatchewan.
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Affiliation(s)
- Xueshuang Mei
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, SE, 751 85, Uppsala, Sweden.
- Department of Otolaryngology, Peking University Shenzhen Hospital, Shenzhen, China.
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Anichstr. 35, A-6020, Innsbruck, Austria
| | - Annelies Schrott-Fischer
- Department of Otolaryngology, Medical University of Innsbruck, Anichstr. 35, A-6020, Innsbruck, Austria
| | - Hao Li
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, SE, 751 85, Uppsala, Sweden
| | - Hanif M Ladak
- Department of Otolaryngology-Head and Neck Surgery, Department of Medical Biophysics and Department of Electrical and Computer Engineering, Western University, London, ON, Canada
| | - Sumit K Agrawal
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, SE, 751 85, Uppsala, Sweden.
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Shin SA, Lyu AR, Jeong SH, Kim TH, Park MJ, Park YH. Acoustic Trauma Modulates Cochlear Blood Flow and Vasoactive Factors in a Rodent Model of Noise-Induced Hearing Loss. Int J Mol Sci 2019; 20:ijms20215316. [PMID: 31731459 PMCID: PMC6862585 DOI: 10.3390/ijms20215316] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/12/2022] Open
Abstract
Noise exposure affects the organ of Corti and the lateral wall of the cochlea, including the stria vascularis and spiral ligament. Although the inner ear vasculature and spiral ligament fibrocytes in the lateral wall consist of a significant proportion of cells in the cochlea, relatively little is known regarding their functional significance. In this study, 6-week-old male C57BL/6 mice were exposed to noise trauma to induce transient hearing threshold shift (TTS) or permanent hearing threshold shift (PTS). Compared to mice with TTS, mice with PTS exhibited lower cochlear blood flow and lower vessel diameter in the stria vascularis, accompanied by reduced expression levels of genes involved in vasodilation and increased expression levels of genes related to vasoconstriction. Ultrastructural analyses by transmission electron microscopy revealed that the stria vascularis and spiral ligament fibrocytes were more damaged by PTS than by TTS. Moreover, mice with PTS expressed significantly higher levels of proinflammatory cytokines in the cochlea (e.g., IL-1β, IL-6, and TNF-α). Overall, our findings suggest that cochlear microcirculation and lateral wall pathologies are differentially modulated by the severity of acoustic trauma and are associated with changes in vasoactive factors and inflammatory responses in the cochlea.
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Affiliation(s)
- Sun-Ae Shin
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (A.-R.L.)
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
| | - Ah-Ra Lyu
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (A.-R.L.)
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
| | - Seong-Hun Jeong
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
| | - Tae Hwan Kim
- Biomedical Convergence Research Center, Chungnam National University Hospital, Daejeon 35015, Korea;
| | - Min Jung Park
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (A.-R.L.)
- Brain Research Institute, College of Medicine, Chungnam National University, Daejeon 35015, Korea
- Correspondence: (M.J.P.); (Y.-H.P.); Tel.: +82-42-280-7697(M.J.P.); Fax: +82-42-253-4059 (M.J.P.)
| | - Yong-Ho Park
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (A.-R.L.)
- Brain Research Institute, College of Medicine, Chungnam National University, Daejeon 35015, Korea
- Correspondence: (M.J.P.); (Y.-H.P.); Tel.: +82-42-280-7697(M.J.P.); Fax: +82-42-253-4059 (M.J.P.)
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6
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Liu W, Luque M, Glueckert R, Danckwardt-Lillieström N, Nordström CK, Schrott-Fischer A, Rask-Andersen H. Expression of Na/K-ATPase subunits in the human cochlea: a confocal and super-resolution microscopy study with special reference to auditory nerve excitation and cochlear implantation. Ups J Med Sci 2019; 124:168-179. [PMID: 31460814 PMCID: PMC6758701 DOI: 10.1080/03009734.2019.1653408] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Background: For the first time the expression of the ion transport protein sodium/potassium-ATPase and its isoforms was analyzed in the human cochlea using light- and confocal microscopy as well as super-resolution structured illumination microscopy. It may increase our understanding of its role in the propagation and processing of action potentials in the human auditory nerve and how electric nerve responses are elicited from auditory prostheses. Material and methods: Archival human cochlear sections were obtained from trans-cochlear surgeries. Antibodies against the Na/K-ATPase β1 isoform together with α1 and α3 were used for immunohistochemistry. An algorithm was applied to assess the expression in various domains. Results: Na/K ATPase β1 subunit was expressed, mostly combined with the α1 isoform. Neurons expressed the β1 subunit combined with α3, while satellite glial cells expressed the α1 isoform without recognized association with β1. Types I and II spiral ganglion neurons and efferent fibers expressed the Na/K-ATPase α3 subunit. Inner hair cells, nerve fibers underneath, and efferent and afferent fibers in the organ of Corti also expressed α1. The highest activity of Na/K-ATPase β1 was at the inner hair cell/nerve junction and spiral prominence. Conclusion: The human auditory nerve displays distinct morphologic features represented in its molecular expression. It was found that electric signals generated via hair cells may not go uninterrupted across the spiral ganglion, but are locally processed. This may be related to particular filtering properties in the human acoustic pathway.
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Affiliation(s)
- Wei Liu
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- Wei Liu
| | - Maria Luque
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Charlotta Kämpfe Nordström
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | | | - Helge Rask-Andersen
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- CONTACT Helge Rask-Andersen Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, SE-751 85, Uppsala, Sweden
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7
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Köles L, Szepesy J, Berekméri E, Zelles T. Purinergic Signaling and Cochlear Injury-Targeting the Immune System? Int J Mol Sci 2019; 20:ijms20122979. [PMID: 31216722 PMCID: PMC6627352 DOI: 10.3390/ijms20122979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 02/06/2023] Open
Abstract
Hearing impairment is the most common sensory deficit, affecting more than 400 million people worldwide. Sensorineural hearing losses currently lack any specific or efficient pharmacotherapy largely due to the insufficient knowledge of the pathomechanism. Purinergic signaling plays a substantial role in cochlear (patho)physiology. P2 (ionotropic P2X and the metabotropic P2Y) as well as adenosine receptors expressed on cochlear sensory and non-sensory cells are involved mostly in protective mechanisms of the cochlea. They are implicated in the sensitivity adjustment of the receptor cells by a K+ shunt and can attenuate the cochlear amplification by modifying cochlear micromechanics. Cochlear blood flow is also regulated by purines. Here, we propose to comprehend this field with the purine-immune interactions in the cochlea. The role of harmful immune mechanisms in sensorineural hearing losses has been emerging in the horizon of cochlear pathologies. In addition to decreasing hearing sensitivity and increasing cochlear blood supply, influencing the immune system can be the additional avenue for pharmacological targeting of purinergic signaling in the cochlea. Elucidating this complexity of purinergic effects on cochlear functions is necessary and it can result in development of new therapeutic approaches in hearing disabilities, especially in the noise-induced ones.
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Affiliation(s)
- László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Ecology, University of Veterinary Medicine, H-1078 Budapest, Hungary.
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary.
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Michanski S, Smaluch K, Steyer AM, Chakrabarti R, Setz C, Oestreicher D, Fischer C, Möbius W, Moser T, Vogl C, Wichmann C. Mapping developmental maturation of inner hair cell ribbon synapses in the apical mouse cochlea. Proc Natl Acad Sci U S A 2019; 116:6415-6424. [PMID: 30867284 PMCID: PMC6442603 DOI: 10.1073/pnas.1812029116] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ribbon synapses of cochlear inner hair cells (IHCs) undergo molecular assembly and extensive functional and structural maturation before hearing onset. Here, we characterized the nanostructure of IHC synapses from late prenatal mouse embryo stages (embryonic days 14-18) into adulthood [postnatal day (P)48] using electron microscopy and tomography as well as optical nanoscopy of apical turn organs of Corti. We find that synaptic ribbon precursors arrive at presynaptic active zones (AZs) after afferent contacts have been established. These ribbon precursors contain the proteins RIBEYE and piccolino, tether synaptic vesicles and their delivery likely involves active, microtubule-based transport pathways. Synaptic contacts undergo a maturational transformation from multiple small to one single, large AZ. This maturation is characterized by the fusion of ribbon precursors with membrane-anchored ribbons that also appear to fuse with each other. Such fusion events are most frequently encountered around P12 and hence, coincide with hearing onset in mice. Thus, these events likely underlie the morphological and functional maturation of the AZ. Moreover, the postsynaptic densities appear to undergo a similar refinement alongside presynaptic maturation. Blockwise addition of ribbon material by fusion as found during AZ maturation might represent a general mechanism for modulating ribbon size.
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Affiliation(s)
- Susann Michanski
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience, InnerEarLab and Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany
| | - Katharina Smaluch
- Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
- Presynaptogenesis and Intracellular Transport in Hair Cells Junior Research Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Anna Maria Steyer
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37075 Göttingen, Germany
| | - Rituparna Chakrabarti
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience, InnerEarLab and Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany
| | - Cristian Setz
- Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
- Presynaptogenesis and Intracellular Transport in Hair Cells Junior Research Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
- Department of Otolaryngology, Head and Neck Surgery, University Medical Center Göttingen, 37075 Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - David Oestreicher
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
- Presynaptogenesis and Intracellular Transport in Hair Cells Junior Research Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
- Department of Otolaryngology, Head and Neck Surgery, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Christian Fischer
- Johann Friedrich Blumenbach Institute for Zoology and Anthropology, Department of Animal Evolution and Biodiversity, Georg August University of Göttingen, 37073 Göttingen, Germany
| | - Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37075 Göttingen, Germany
| | - Tobias Moser
- Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37075 Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
- Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Christian Vogl
- Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany;
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
- Presynaptogenesis and Intracellular Transport in Hair Cells Junior Research Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Carolin Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience, InnerEarLab and Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany;
- Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
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Dong Y, Zhang C, Frye M, Yang W, Ding D, Sharma A, Guo W, Hu BH. Differential fates of tissue macrophages in the cochlea during postnatal development. Hear Res 2018; 365:110-126. [PMID: 29804721 PMCID: PMC6026078 DOI: 10.1016/j.heares.2018.05.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/03/2018] [Accepted: 05/14/2018] [Indexed: 12/11/2022]
Abstract
The cochlea contains macrophages. These cells participate in inflammatory responses to cochlear pathogenesis. However, it is not clear how and when these cells populate the cochlea during postnatal development. The current study aims to determine the postnatal development of cochlear macrophages with the focus on macrophage development in the organ of Corti and the basilar membrane. Cochleae were collected from C57BL/6J mice at ages of postnatal day (P) 1 to P21, as well as from mature mice (1-4 months). Macrophages were identified based on their expression of F4/80 and Iba1, as well as their unique morphologies. Two sets of macrophages were identified in the regions of the organ of Corti and the basilar membrane. One set resides on the scala tympani side of the basilar membrane. These cells have a round shape at P1 and start to undergo site-specific differentiation at P4. Apical macrophages adopt a dendritic shape. Middle and basal macrophages take on an irregular shape with short projections. Basal macrophages further differentiate into an amoeboid shape. The other set of macrophages resides above the basilar membrane, either beneath the cells of the organ of Corti or along the spiral vessel of the basilar membrane. As the sensory epithelium matures, these cells undergo developmental death with the phenotypes of apoptosis. Macrophages are also identified in the spiral ligament, spiral limbus, and neural regions. Their numbers decrease during postnatal development. Together, these results suggest a dynamic rearrangement of the macrophage population during postnatal cochlear development.
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Affiliation(s)
- Youyi Dong
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Celia Zhang
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Mitchell Frye
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Weiping Yang
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA; Department of Otolaryngology and Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, China.
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Ashu Sharma
- Department of Oral Biology, University at Buffalo, NY, 14214, USA.
| | - Weiwei Guo
- Department of Otolaryngology and Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, China.
| | - Bo Hua Hu
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
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10
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Mahendrasingam S, Fettiplace R, Alagramam KN, Cross E, Furness DN. Spatiotemporal changes in the distribution of LHFPL5 in mice cochlear hair bundles during development and in the absence of PCDH15. PLoS One 2017; 12:e0185285. [PMID: 29069081 PMCID: PMC5656302 DOI: 10.1371/journal.pone.0185285] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 09/08/2017] [Indexed: 11/18/2022] Open
Abstract
Mechanosensory transduction by vertebrate hair cells depends on a protein complex at the tips of shorter stereocilia associated with mechanoelectrical transduction channels activated by tip links in the hair bundle. In mammalian hair cells, this complex includes transmembrane channel-like protein subunit 1 (TMC1), lipoma HMGIC fusion partner-like 5 protein (LHFPL5) and protocadherin 15 (PCDH15), a lower-end component of the tip link. TMC1 interacts with LHFPL5 and PCDH15 but how the complex develops to maturity, and the relationships between these proteins, remains uncertain. Here we evaluate the spatiotemporal development of LHFPL5 distributions in mouse cochlear hair bundles by immunofluorescence and immunogold transmission electron microscopy, from postnatal day 0 (P0) through P21 in wild type and PCDH15-deficient mice. At P0, hair bundles contain many short microvilli-like processes which we term unranked stereocilia, and a subset of lengthening rows, adjacent to a kinocilium. LHFPL5 is distributed throughout the bundle, including on stereocilia tips and the kinocilium. At P3, 4-to-6 rows of ranked stereocilia are evident, total LHFPL5 expression peaks, and LHFPL5 is localised to ranked stereocilia tips of all rows and to lower shaft/ankle links. By P12, the bundle has a mature pattern with 3 ranked rows but virtually no unranked stereocilia or kinocilium; LHFPL5 expression has declined and become restricted to the tips of shorter stereocilia. Throughout development from P0, expression of LHFPL5 is greater overall on apical than basal bundles, but there is, on average, an equal amount of labelling per labelled tip. In P3 mice lacking PCDH15, LHFPL5 labelling is not at the tips but is primarily on unranked stereocilia and lower lateral links. These data show that LHFPL5 is already present in the MET apparatus at P0 but requires PCDH15 at P3 to remain there. Shaft/ankle link localisation suggests it interacts with link proteins other than PCDH15.
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Affiliation(s)
| | - Robert Fettiplace
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, WI, United States of America
| | - Kumar N. Alagramam
- Otolaryngology Head and Neck Surgery, University Hospital Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, OH, United States of America
| | - Ellen Cross
- School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
| | - David N. Furness
- School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
- * E-mail:
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11
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Watabe T, Xu M, Watanabe M, Nabekura J, Higuchi T, Hori K, Sato MP, Nin F, Hibino H, Ogawa K, Masuda M, Tanaka KF. Time-controllable Nkcc1 knockdown replicates reversible hearing loss in postnatal mice. Sci Rep 2017; 7:13605. [PMID: 29051615 PMCID: PMC5648887 DOI: 10.1038/s41598-017-13997-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/04/2017] [Indexed: 11/08/2022] Open
Abstract
Identification of the causal effects of specific proteins on recurrent and partially reversible hearing loss has been difficult because of the lack of an animal model that provides reversible gene knockdown. We have developed the transgenic mouse line Actin-tTS::Nkcc1 tetO/tetO for manipulatable expression of the cochlear K+ circulation protein, NKCC1. Nkcc1 transcription was blocked by the binding of a tetracycline-dependent transcriptional silencer to the tetracycline operator sequences inserted upstream of the Nkcc1 translation initiation site. Administration of the tetracycline derivative doxycycline reversibly regulated Nkcc1 knockdown. Progeny from pregnant/lactating mothers fed doxycycline-free chow from embryonic day 0 showed strong suppression of Nkcc1 expression (~90% downregulation) and Nkcc1 null phenotypes at postnatal day 35 (P35). P35 transgenic mice from mothers fed doxycycline-free chow starting at P0 (delivery) showed weaker suppression of Nkcc1 expression (~70% downregulation) and less hearing loss with mild cochlear structural changes. Treatment of these mice at P35 with doxycycline for 2 weeks reactivated Nkcc1 transcription to control levels and improved hearing level at high frequency; i.e., these doxycycline-treated mice exhibited partially reversible hearing loss. Thus, development of the Actin-tTS::Nkcc1 tetO/tetO transgenic mouse line provides a mouse model for the study of variable hearing loss through reversible knockdown of Nkcc1.
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Affiliation(s)
- Takahisa Watabe
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Ming Xu
- Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu city, Shizuoka, 431-3192, Japan
| | - Junichi Nabekura
- Division of Homeostatic Development, National Institute for Physiological Sciences, 38 Nishigonaka Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - Taiga Higuchi
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Karin Hori
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Mitsuo P Sato
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
- Center for Transdisciplinary Research, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata, 950-2181, Japan
| | - Kaoru Ogawa
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Masatsugu Masuda
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
- Department of Otolaryngology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo, 181-8611, Japan.
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
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12
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Ada S, Hanci D, Ulusoy S, Vejselova D, Burukoglu D, Muluk NB, Cingi C. Potential protective effect of N-acetyl cysteine in acoustic trauma: An experimental study using scanning electron microscopy. ADV CLIN EXP MED 2017; 26:893-897. [PMID: 29068588 DOI: 10.17219/acem/64332] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Oxidative stress has been associated with pathological processes involved in acoustic trauma. OBJECTIVES In this prospective experimental study, we investigated the potential preventive effect of N-acetyl cysteine (NAC) in rats exposed to acoustic trauma (AT). Light microscopic and scanning electron microscopic (SEM) evaluations were performed. MATERIAL AND METHODS Healthy Wistar albino rats (n = 18) were divided into 3 groups: group 1 (control group, n = 6), group 2 (acoustic trauma group, n = 6), and group 3 (AT+NAC group, n = 6). The rats in group 2 were exposed to AT. The rats in group 3 received NAC at a dose of 100 mg/kg/day by gavage for 7 days, and then 10 min after the 7th-day dose, they were exposed to AT. RESULTS From light and scanning electron microscopy evaluations in the control group, the cochlear structure and epithelium were normal. In group 2 (AT group), extensive hair cell loss was observed in the cochlea by light microscopy evaluation. In the SEM evaluation, various epithelial damage and loss of stereocilia were also observed. In group 3 (AT+NAC group), decreased damage with preserved cochlear structures was seen by light microscopy. In the SEM evaluation, although stereocilia loss was also seen, nearly normal cell structures and vertical and symmetrical alignment of stereocilia structures were observed compared to the AT group. CONCLUSIONS NAC reduced cochlear damage due to acoustic trauma. Because NAC has antioxidant capacity, AT mat have caused an increase in free radicals and death of outer hair cells. NAC is an antioxidant agent and it prevented cochlear damage due to AT in rats.
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MESH Headings
- Acetylcysteine/pharmacology
- Animals
- Antioxidants/pharmacology
- Cochlea/drug effects
- Cochlea/metabolism
- Cochlea/ultrastructure
- Disease Models, Animal
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Epithelial Cells/ultrastructure
- Hair Cells, Auditory/drug effects
- Hair Cells, Auditory/metabolism
- Hair Cells, Auditory/ultrastructure
- Hearing Loss, Noise-Induced/etiology
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/prevention & control
- Microscopy, Electrochemical, Scanning
- Noise/adverse effects
- Oxidative Stress/drug effects
- Rats, Wistar
- Stereocilia/drug effects
- Stereocilia/ultrastructure
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Affiliation(s)
- Servet Ada
- Luleburgaz State Hospital, ENT Department, Kırklareli, Turkey
| | - Deniz Hanci
- Okmeydanı Training and Research Hospital, ENT Clinics, Istanbul,Turkey
| | - Seçkin Ulusoy
- Şişli Kolan International Hospital, ENT Clinics, Istanbul, Turkey
| | - Djanan Vejselova
- Department of Biology, Faculty of Science, Anadolu University, Eskişehir, Turkey
| | - Dilek Burukoglu
- Department of Histology, Medical Faculty, Eskişehir Osmangazi University, Turkey
| | - Nuray Bayar Muluk
- Department of Otorhinolaryngology, Faculty of Medicine, Kirikkale University, Turkey
| | - Cemal Cingi
- Department of Otorhinolaryngology, Medical Faculty, Eskişehir Osmangazi University, Turkey
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13
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Tachos NS, Sakellarios AI, Rigas G, Isailovic V, Ni G, Bohnke F, Filipovic N, Bibas T, Fotiadis DI. Middle and inner ear modelling: from microCT images to 3D reconstruction and coupling of models. Annu Int Conf IEEE Eng Med Biol Soc 2017; 2016:5961-5964. [PMID: 28269610 DOI: 10.1109/embc.2016.7592086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We present finite element (FE) modeling approaches of ear mechanics including 3-dimensional (3D) reconstruction of the human middle and inner ear. Specifically, we demonstrate a semi-automatic methodology for the 3D reconstruction of the inner ear structures, a FE harmonic response model of the middle ear to predict the stapes footplate frequency response, a 2D FE slice model of the cochlea for the coupled response at the micromechanical level for either acoustic or electrical excitation and a coupled FE middle ear model with a simplified cochlea box model to simulate the basilar membrane velocity in response to acoustic excitation. The proposed methodologies are validated against experimental and literature data and the results are in good agreement.
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14
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Rask-Andersen H, Li H, Löwenheim H, Müller M, Pfaller K, Schrott-Fischer A, Glueckert R. Supernumerary human hair cells-signs of regeneration or impaired development? A field emission scanning electron microscopy study. Ups J Med Sci 2017; 122:11-19. [PMID: 28145795 PMCID: PMC5361427 DOI: 10.1080/03009734.2016.1271843] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Current attempts to regenerate cochlear sensorineural structures motivate further inspection of the human organ of hearing. Here, we analyzed the supernumerary inner hair cell (sIHC), a possible sign of regeneration and cell replacement. METHODS Human cochleae were studied using field emission scanning electron microscopy (FESEM; maximum resolution 2 nm) obtained from individuals aged 44, 48, and 58 years with normal sensorineural pure-tone average (PTA) thresholds (PTA <20 dB). The wasted tissue was harvested during trans-cochlear approaches and immediately fixed for ultrastructural analysis. RESULTS All specimens exhibited sIHCs at all turns except at the extreme lower basal turn. In one specimen, it was possible to image and count the inner hair cells (IHCs) along the cochlea representing the 0.2 kHz-8 kHz region according to the Greenwood place/frequency scale. In a region with 2,321 IHCs, there were 120 scattered one-cell losses or 'gaps' (5%). Forty-two sIHCs were present facing the modiolus. Thirty-eight percent of the sIHCs were located near a 'gap' in the IHC row (±6 IHCs). CONCLUSIONS The prevalence of ectopic inner hair cells was higher than expected. The morphology and placement could reflect a certain ongoing regeneration. Further molecular studies are needed to verify if the regenerative capacity of the human auditory periphery might have been underestimated.
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Affiliation(s)
- Helge Rask-Andersen
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- Department of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- CONTACT Helge Rask-Andersen Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, SE-751 85, Uppsala, Sweden
| | - Hao Li
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- Department of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | - Hubert Löwenheim
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
- Medical Campus University of Oldenburg School of Medicine and Health Sciences, European Medical School, Oldenburg, Germany
- Research Center of Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Marcus Müller
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
- Medical Campus University of Oldenburg School of Medicine and Health Sciences, European Medical School, Oldenburg, Germany
- Research Center of Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Kristian Pfaller
- Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany
| | - Annelies Schrott-Fischer
- Department of Histology and Molecular Cell Biology, Institute of Anatomy and Histology, Medical University of Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Department of Histology and Molecular Cell Biology, Institute of Anatomy and Histology, Medical University of Innsbruck, Innsbruck, Austria
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15
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Carraro M, Almishaal A, Hillas E, Firpo M, Park A, Harrison RV. Cytomegalovirus (CMV) Infection Causes Degeneration of Cochlear Vasculature and Hearing Loss in a Mouse Model. J Assoc Res Otolaryngol 2016; 18:263-273. [PMID: 27995350 DOI: 10.1007/s10162-016-0606-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/24/2016] [Indexed: 12/20/2022] Open
Abstract
Cytomegalovirus (CMV) infection is one of the most common causes of congenital hearing loss in children. We have used a murine model of CMV infection to reveal functional and structural cochlear pathogenesis. The cerebral cortex of Balb/c mice (Mus musculus) was inoculated with 2000 pfu (plaque forming units) of murine CMV on postnatal day 3. At 6 weeks of age, cochlear function was monitored using auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) measures. Histological assessment of cochlear vasculature using a corrosion cast technique was made at 8 weeks. Vascular casts of mCMV-damaged cochleas, and those of untreated control animals, were examined using scanning electron microscopy. We find very large variations in the degree of vascular damage in animals given identical viral injections (2000 pfu). The primary lesion caused by CMV infection is to the stria vascularis and to the adjacent spiral limbus capillary network. Capillary beds of the spiral ligament are generally less affected. The initial vascular damage is found in the mid-apical turn and appears to progress to more basal cochlear regions. After viral migration to the inner ear, the stria vascularis is the primary affected structure. We suggest that initial auditory threshold losses may relate to the poor development or maintenance of the endocochlear potential caused by strial dysfunction. Our increased understanding of the pathogenesis of CMV-related hearing loss is important for defining methods for early detection and treatment.
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Affiliation(s)
- Mattia Carraro
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Auditory Science Laboratory, Neuroscience and Mental Health Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Ali Almishaal
- Department of Communication Sciences and Disorders, University of Utah, Salt Lake City, UT, USA
| | - Elaine Hillas
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
| | - Matthew Firpo
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
| | - Albert Park
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
- Department of Otolaryngology, University of Utah, Salt Lake City, UT, USA
| | - Robert V Harrison
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
- Auditory Science Laboratory, Neuroscience and Mental Health Program, The Hospital for Sick Children, Toronto, ON, Canada.
- Department of Otolaryngology, Head and Neck Surgery, University of Toronto, Toronto, ON, Canada.
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16
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Yu F, Hao S, Yang B, Zhao Y, Yang J. Low Iron Diet Increases Susceptibility to Noise-Induced Hearing Loss in Young Rats. Nutrients 2016; 8:nu8080456. [PMID: 27483303 PMCID: PMC4997371 DOI: 10.3390/nu8080456] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/20/2016] [Accepted: 07/25/2016] [Indexed: 12/25/2022] Open
Abstract
We evaluated the role of iron deficiency (ID) without anemia on hearing function and cochlear pathophysiology of young rats before and after noise exposure. We used rats at developmental stages as an animal model to induce ID without anemia by dietary iron restriction. We have established this dietary restriction model in the rat that should enable us to study the effects of iron deficiency in the absence of severe anemia on hearing and ribbon synapses. Hearing function was measured on Postnatal Day (PND) 21 after induction of ID using auditory brainstem response (ABR). Then, the young rats were exposed to loud noise on PND 21. After noise exposure, hearing function was again measured. We observed the morphology of ribbon synapses, hair cells and spiral ganglion cells (SGCs), and assessed the expression of myosin VIIa, vesicular glutamate transporter 3 and prestin in the cochlea. ID without anemia did not elevate ABR threshold shifts, but reduced ABR wave I peak amplitude of young rats. At 70, 80, and 90 dB SPL, amplitudes of wave I (3.11 ± 0.96 µV, 3.52 ± 1.31 µV, and 4.37 ± 1.08 µV, respectively) in pups from the ID group were decreased compared to the control (5.92 ± 1.67 µV, 6.53 ± 1.70 µV, and 6.90 ± 1.76 µV, respectively) (p < 0.05). Moreover, ID without anemia did not impair the morphology hair cells and SGCs, but decreased the number of ribbon synapses. Before noise exposure, the mean number of ribbon synapses per inner hair cell (IHC) was significantly lower in the ID group (8.44 ± 1.21) compared to that seen in the control (13.08 ± 1.36) (p < 0.05). In addition, the numbers of ribbon synapses per IHC of young rats in the control (ID group) were 6.61 ± 1.59, 3.07 ± 0.83, 5.85 ± 1.63 and 12.25 ± 1.97 (3.75 ± 1.45, 2.03 ± 1.08, 3.81 ± 1.70 and 4.01 ± 1.65) at 1, 4, 7 and 14 days after noise exposure, respectively. Moreover, ABR thresholds at 4 and 8 kHz in young rats from the ID group were significantly elevated at 7 and 14 days after noise exposure compared to control (p < 0.05). The average number of young rat SGCs from the ID group were significantly decreased in the basal turn of the cochlea compared to the control (p < 0.05). Therefore, ID without anemia delayed the recovery from noise-induced hearing loss and ribbon synapses damage, increased SGCs loss, and upregulated prestin after noise exposure. Thus, the cochleae in rat pups with ID without anemia were potentially susceptible to loud noise exposure, and this deficit may be attributed to the reduction of ribbon synapses and SGCs.
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MESH Headings
- Anemia, Iron-Deficiency/diet therapy
- Anemia, Iron-Deficiency/metabolism
- Anemia, Iron-Deficiency/pathology
- Anemia, Iron-Deficiency/physiopathology
- Animals
- Auditory Cortex/metabolism
- Auditory Cortex/physiopathology
- Auditory Cortex/ultrastructure
- Auditory Threshold/radiation effects
- Brain Stem/metabolism
- Brain Stem/physiopathology
- Brain Stem/ultrastructure
- Cochlea/innervation
- Cochlea/metabolism
- Cochlea/physiopathology
- Cochlea/ultrastructure
- Cochlear Nerve/metabolism
- Cochlear Nerve/physiopathology
- Cochlear Nerve/radiation effects
- Cochlear Nerve/ultrastructure
- Disease Models, Animal
- Disease Susceptibility
- Female
- Gene Expression Regulation, Developmental/radiation effects
- Hearing Loss, Noise-Induced/etiology
- Hearing Loss, Noise-Induced/prevention & control
- Iron, Dietary/therapeutic use
- Male
- Microscopy, Electron, Scanning
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Noise/adverse effects
- Nutritional Status
- Random Allocation
- Rats, Sprague-Dawley
- Spiral Ganglion/metabolism
- Spiral Ganglion/physiopathology
- Spiral Ganglion/ultrastructure
- Weaning
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Affiliation(s)
- Fei Yu
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, China.
| | - Shuai Hao
- Department of Otolaryngology, First Affiliated Hospital of China Medical University, No. 155, Nanjing North Street, Heping District, Shenyang 110001, China.
| | - Bo Yang
- Department of Otolaryngology, First Affiliated Hospital of China Medical University, No. 155, Nanjing North Street, Heping District, Shenyang 110001, China.
| | - Yue Zhao
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, China.
| | - Jun Yang
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, China.
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17
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Shi L, Liu K, Wang H, Zhang Y, Hong Z, Wang M, Wang X, Jiang X, Yang S. Noise induced reversible changes of cochlear ribbon synapses contribute to temporary hearing loss in mice. Acta Otolaryngol 2015; 135:1093-102. [PMID: 26139555 DOI: 10.3109/00016489.2015.1061699] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION Noise exposure can cause a decline in cochlear ribbon synapses and result in consequent hearing loss. The reduction of synaptic puncta appears reversible and may contribute to hearing restoration in mice after noise exposure. OBJECTIVE To detect whether noise induced reversible changes of cochlear ribbon synapses contribute to temporary hearing loss in C57BL/6J mice. METHODS The mice were assigned randomly to five groups and exposed to white noise at 110 dB SPL for 2 h except the control group. ABR thresholds were acquired before noise exposure (control), immediately following exposure (Day 0), or on Days 4, 7, or 14 after noise exposure. Light microscopy, scanning emission microscopy, and whole mounts examination was utilized to study whether there is morphology change of outer hair cells (OHC), inner hair cells (IHC), or spiral ganglion cells (SGN) due to the 110 dB white noise. Moreover, experimental approaches, including immunostaining and confocal microcopy, were used to detect whether ribbon synapses were the primary targets of noise-induced temporary hearing loss. RESULT Exposure to 110 dB white noise for 2 h induced TTS in mice, with the maximal ABR threshold elevations seen on the 4(th) day after noise exposure. There were no significant morphological changes in the cochlea. Paralleled changes of pre-synaptic ribbons in both the number and post-synaptic density (PSDs) during this noise exposure were detected. The number of pre-synaptic ribbon, post-synaptic density (PSDs), and co-localized puncta correlated with the shifts of ABR thresholds. Moreover, a complete recovery of ABR thresholds and synaptic puncta was seen on the 14(th) day after the noise stimulations.
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MESH Headings
- Acoustic Stimulation/adverse effects
- Animals
- Auditory Threshold/physiology
- Cochlea/metabolism
- Cochlea/physiopathology
- Cochlea/ultrastructure
- Disease Models, Animal
- Evoked Potentials, Auditory, Brain Stem/physiology
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/ultrastructure
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/ultrastructure
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Mice
- Mice, Inbred C57BL
- Microscopy, Confocal
- Microscopy, Electron, Scanning
- Neuronal Plasticity
- Spiral Ganglion/metabolism
- Spiral Ganglion/ultrastructure
- Synapses
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Affiliation(s)
- Lin Shi
- a 1 Department of Otorhinolaryngology, The First Affiliated Hospital, China Medical University , Shenyang 110001, PR China
- c 3 Department of Otorhinolaryngology, The First Affiliated Hospital, Dalian Medical University , Dalian 116013, PR China
| | - Ke Liu
- b 2 Department of Otolaryngology, Head & Neck Surgery, The Institute of Otolaryngology, Chinese PLA General Hospital , 28 Fuxing Road, Beijing, 100853, PR China
| | - Haolin Wang
- c 3 Department of Otorhinolaryngology, The First Affiliated Hospital, Dalian Medical University , Dalian 116013, PR China
| | - Yue Zhang
- b 2 Department of Otolaryngology, Head & Neck Surgery, The Institute of Otolaryngology, Chinese PLA General Hospital , 28 Fuxing Road, Beijing, 100853, PR China
| | - Zhijun Hong
- c 3 Department of Otorhinolaryngology, The First Affiliated Hospital, Dalian Medical University , Dalian 116013, PR China
| | - Mingyu Wang
- c 3 Department of Otorhinolaryngology, The First Affiliated Hospital, Dalian Medical University , Dalian 116013, PR China
| | - Xiaoyu Wang
- b 2 Department of Otolaryngology, Head & Neck Surgery, The Institute of Otolaryngology, Chinese PLA General Hospital , 28 Fuxing Road, Beijing, 100853, PR China
| | - Xuejun Jiang
- a 1 Department of Otorhinolaryngology, The First Affiliated Hospital, China Medical University , Shenyang 110001, PR China
| | - Shiming Yang
- b 2 Department of Otolaryngology, Head & Neck Surgery, The Institute of Otolaryngology, Chinese PLA General Hospital , 28 Fuxing Road, Beijing, 100853, PR China
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Abstract
CONCLUSIONS The vascular endothelial growth factor (VEGF)-mediated mechanism of endothelial progenitor cell (EPC) mobilization, migration, and differentiation may occur in response to noise-induced acoustic trauma of the cochlea, leading to the protection of cochlear function. OBJECTIVE The purpose of this study was to analyze changes in the cochlear vessel under an intensive noise environment. METHODS Sixty male Sprague-Dawley rats were randomly divided into six groups. Acoustic trauma was induced by 120 dB SPL white noise for 4 h. Auditory function was evaluated by the auditory brainstem response threshold. Morphological changes of the cochleae, the expression of VEGF, and the circulation of EPCs in the peripheral blood were studied by immunohistochemistry, Western blotting analysis, scanning electron microscopy, and flow cytometry. RESULTS Vascular recovery of the cochlea began after noise exposure. The change in the number of EPCs was consistent with the expression of VEGF at different time points after noise exposure. We propose that VEGF evokes specific permeable and chemotactic effects on the vascular endothelial cells. These effects can mobilize EPCs into the peripheral blood, leading the EPCs to target damaged sites and to exert a neoangiogenic effect.
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Morales J, Garcia-Martinez V. Differentiation of hair cells in the reptile basilar papilla. Adv Otorhinolaryngol 2015; 45:111-8. [PMID: 2077882 DOI: 10.1159/000418944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J Morales
- Departamento de Otorrinolaringologia, Facultad de Medicina, Badajoz, Universidad de Extremadura, Spain
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20
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Veldman JE, Albers FM, Ruding PR, de Groot JC, Huizing EH. Functional ultrastructure of the inner ear in experimental hydrops. Adv Otorhinolaryngol 2015; 45:154-74. [PMID: 2077888 DOI: 10.1159/000418951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J E Veldman
- Department of Otorhinolaryngology, University of Utrecht, The Netherlands
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25
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Yang C, Zhang W, Liu X, Liang Y, Li P, Zhang Y, Yuan Y. [The influence of the single different radiation dose and time on the microscopic structure and ultrastructure of Balb/c mice]. Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2014; 28:979-982. [PMID: 25248266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVE To observe the influence of the single different radiation dose and time on the microscopic structure and ultrastructure of Balb/c Mice. METHOD Sixteen four-week-old mice were randomly divided into four groups, control group and three experimental groups, then every experimental group was randomly divided into two groups which were respectively sacrificed on the third and seventh day after exposure to different doses of 8, 12, 16 Gy radiation, then paraffin embedding, tissue section, HE staining and scanning electron microscope, observation were performed after a cochlear specimen collected. RESULT Inner hair cells and outer hair cells arranged in order, no lodging, disorder or missing in control group under scanning electron microscope. Slight lodgy or disorder occured in inner cells and outer hair cells were missing sometimes in exposed animals,which meat irrespective of irradiation dose. CONCLUSION Slight changes of ultrastructure of Balb/c Mice occured in the early period when given eaqual to or less than 16 Gy radiation.
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Hao X, Xing Y, Moore MW, Zhang J, Han D, Schulte BA, Dubno JR, Lang H. Sox10 expressing cells in the lateral wall of the aged mouse and human cochlea. PLoS One 2014; 9:e97389. [PMID: 24887110 PMCID: PMC4041576 DOI: 10.1371/journal.pone.0097389] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/17/2014] [Indexed: 12/20/2022] Open
Abstract
Age-related hearing loss (presbycusis) is a common human disorder, affecting one in three Americans aged 60 and over. Previous studies have shown that presbyacusis is associated with a loss of non-sensory cells in the cochlear lateral wall. Sox10 is a transcription factor crucial to the development and maintenance of neural crest-derived cells including some non-sensory cell types in the cochlea. Mutations of the Sox10 gene are known to cause various combinations of hearing loss and pigmentation defects in humans. This study investigated the potential relationship between Sox10 gene expression and pathological changes in the cochlear lateral wall of aged CBA/CaJ mice and human temporal bones from older donors. Cochlear tissues prepared from young adult (1–3 month-old) and aged (2–2.5 year-old) mice, and human temporal bone donors were examined using quantitative immunohistochemical analysis and transmission electron microscopy. Cells expressing Sox10 were present in the stria vascularis, outer sulcus and spiral prominence in mouse and human cochleas. The Sox10+ cell types included marginal and intermediate cells and outer sulcus cells, including those that border the scala media and those extending into root processes (root cells) in the spiral ligament. Quantitative analysis of immunostaining revealed a significant decrease in the number of Sox10+ marginal cells and outer sulcus cells in aged mice. Electron microscopic evaluation revealed degenerative alterations in the surviving Sox10+ cells in aged mice. Strial marginal cells in human cochleas from donors aged 87 and older showed only weak immunostaining for Sox10. Decreases in Sox10 expression levels and a loss of Sox10+ cells in both mouse and human aged ears suggests an important role of Sox10 in the maintenance of structural and functional integrity of the lateral wall. A loss of Sox10+ cells may also be associated with a decline in the repair capabilities of non-sensory cells in the aged ear.
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Affiliation(s)
- Xinping Hao
- Department of Otolaryngology – Head & Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Yazhi Xing
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Michael W. Moore
- Department of Otolaryngology – Head & Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Jianning Zhang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Department of Otolaryngology, Shanghai Yueyang Integrated Medicine Hospital, Shanghai, China
| | - Demin Han
- Department of Otolaryngology – Head & Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- * E-mail: (HL); (DH)
| | - Bradley A. Schulte
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Department of Otolaryngology – Head & Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Judy R. Dubno
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Department of Otolaryngology – Head & Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail: (HL); (DH)
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Thomas PV, Cheng AL, Colby CC, Liu L, Patel CK, Josephs L, Duncan RK. Localization and proteomic characterization of cholesterol-rich membrane microdomains in the inner ear. J Proteomics 2014; 103:178-93. [PMID: 24713161 DOI: 10.1016/j.jprot.2014.03.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/25/2014] [Accepted: 03/26/2014] [Indexed: 12/14/2022]
Abstract
UNLABELLED Biological membranes organize and compartmentalize cell signaling into discrete microdomains, a process that often involves stable, cholesterol-rich platforms that facilitate protein-protein interactions. Polarized cells with distinct apical and basolateral cell processes rely on such compartmentalization to maintain proper function. In the cochlea, a variety of highly polarized sensory and non-sensory cells are responsible for the early stages of sound processing in the ear, yet little is known about the mechanisms that traffic and organize signaling complexes within these cells. We sought to determine the prevalence, localization, and protein composition of cholesterol-rich lipid microdomains in the cochlea. Lipid raft components, including the scaffolding protein caveolin and the ganglioside GM1, were found in sensory, neural, and glial cells. Mass spectrometry of detergent-resistant membrane (DRM) fractions revealed over 600 putative raft proteins associated with subcellular localization, trafficking, and metabolism. Among the DRM constituents were several proteins involved in human forms of deafness including those involved in ion homeostasis, such as the potassium channel KCNQ1, the co-transporter SLC12A2, and gap junction proteins GJA1 and GJB6. The presence of caveolin in the cochlea and the abundance of proteins in cholesterol-rich DRM suggest that lipid microdomains play a significant role in cochlear physiology. BIOLOGICAL SIGNIFICANCE Although mechanisms underlying cholesterol synthesis, homeostasis, and compartmentalization in the ear are poorly understood, there are several lines of evidence indicating that cholesterol is a key modulator of cochlear function. Depletion of cholesterol in mature sensory cells alters calcium signaling, changes excitability during development, and affects the biomechanical processes in outer hair cells that are responsible for hearing acuity. More recently, we have established that the cholesterol-modulator beta-cyclodextrin is capable of inducing significant and permanent hearing loss when delivered subcutaneously at high doses. We hypothesize that proteins involved in cochlear homeostasis and otopathology are partitioned into cholesterol-rich domains. The results of a large-scale proteomic analysis point to metabolic processes, scaffolding/trafficking, and ion homeostasis as particularly associated with cholesterol microdomains. These data offer insight into the proteins and protein families that may underlie cholesterol-mediated effects in sensory cell excitability and cyclodextrin ototoxicity.
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Affiliation(s)
- Paul V Thomas
- Kresge Hearing Research Institute, 5323 Medical Science Building I, 1150 West Medical Center Drive, The University of Michigan, Ann Arbor, MI 48109-5616, USA
| | - Andrew L Cheng
- Kresge Hearing Research Institute, 5323 Medical Science Building I, 1150 West Medical Center Drive, The University of Michigan, Ann Arbor, MI 48109-5616, USA
| | - Candice C Colby
- Kresge Hearing Research Institute, 5323 Medical Science Building I, 1150 West Medical Center Drive, The University of Michigan, Ann Arbor, MI 48109-5616, USA
| | - Liqian Liu
- Kresge Hearing Research Institute, 5323 Medical Science Building I, 1150 West Medical Center Drive, The University of Michigan, Ann Arbor, MI 48109-5616, USA
| | - Chintan K Patel
- Kresge Hearing Research Institute, 5323 Medical Science Building I, 1150 West Medical Center Drive, The University of Michigan, Ann Arbor, MI 48109-5616, USA
| | - Lydia Josephs
- Kresge Hearing Research Institute, 5323 Medical Science Building I, 1150 West Medical Center Drive, The University of Michigan, Ann Arbor, MI 48109-5616, USA
| | - R Keith Duncan
- Kresge Hearing Research Institute, 5323 Medical Science Building I, 1150 West Medical Center Drive, The University of Michigan, Ann Arbor, MI 48109-5616, USA.
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Mujica-Mota MA, Gasbarrino K, Rappaport JM, Shapiro RS, Daniel SJ. The effect of caffeine on hearing in a guinea pig model of acoustic trauma. Am J Otolaryngol 2014; 35:99-105. [PMID: 24406118 DOI: 10.1016/j.amjoto.2013.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 11/25/2013] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Caffeine is a widely consumed substance affecting the metabolism of adenosine and cellular metabolism of calcium. Noise also affects these metabolic pathways while inducing hearing loss. The aim of this study was to determine the effect of daily intake of caffeine on hearing loss after an episode of acoustic trauma in guinea pigs. MATERIALS AND METHODS In this pilot study, forty guinea pigs were randomly divided into four groups: group I (control, n=10) received intraperitoneal saline, group II (n=10) received intraperitoneal caffeine (120 mg/kg/day) for 14 days, group III (n=10) was exposed to noise (tone of 6 kHz at 120 dB for one hour) and group IV (n=10) was exposed to noise as group III and received caffeine as group II. Auditory brainstem responses were measured at four different frequencies (8, 16, 20, and 25 kHz) prior to and at intervals of 1h, 3 days, 10 days, and 14 days after the initial treatment. On day 14, morphological analysis was performed to assess the effects of caffeine on acoustic trauma. RESULTS Aggravated hearing loss was observed in group IV after 10 days of follow-up. After 14 days, one of the four frequencies (8 kHz) tested showed statistically significant greater impairment in hearing (8.2 ± 3.6 dB, p=0.026). Auditory hair cells showed no difference while spiral ganglion cell counts were diminished in group IV (p<0.05). CONCLUSION These findings indicate that caffeine may have a detrimental effect on hearing recovery after a single event of acoustic trauma.
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MESH Headings
- Animals
- Caffeine/administration & dosage
- Cochlea/ultrastructure
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Evoked Potentials, Auditory, Brain Stem/drug effects
- Female
- Guinea Pigs
- Hearing/drug effects
- Hearing Loss, Noise-Induced/drug therapy
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Injections, Intraperitoneal
- Microscopy, Electron, Scanning
- Pilot Projects
- Purinergic P1 Receptor Antagonists/administration & dosage
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Affiliation(s)
- Mario A Mujica-Mota
- McGill Auditory Sciences Laboratory, Montreal Children's Hospital, Department of Otolaryngology-Head and Neck Surgery, McGill University, Montréal, Québec, Canada
| | - Karina Gasbarrino
- McGill Auditory Sciences Laboratory, Montreal Children's Hospital, Department of Otolaryngology-Head and Neck Surgery, McGill University, Montréal, Québec, Canada
| | - Jamie M Rappaport
- McGill Auditory Sciences Laboratory, Montreal Children's Hospital, Department of Otolaryngology-Head and Neck Surgery, McGill University, Montréal, Québec, Canada; Jewish General Hospital, Department of Otolaryngology-Head and Neck Surgery, Montréal, Québec, Canada
| | - Robert S Shapiro
- McGill Auditory Sciences Laboratory, Montreal Children's Hospital, Department of Otolaryngology-Head and Neck Surgery, McGill University, Montréal, Québec, Canada
| | - Sam J Daniel
- McGill Auditory Sciences Laboratory, Montreal Children's Hospital, Department of Otolaryngology-Head and Neck Surgery, McGill University, Montréal, Québec, Canada.
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Heinrich UR, Brieger J, Striedter C, Fischer I, Schmidtmann I, Li H, Mann WJ, Helling K. 17β-Estradiol reduces nitric oxide production in the Guinea pig cochlea. Horm Metab Res 2013; 45:887-92. [PMID: 23794402 DOI: 10.1055/s-0033-1347200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Intense noise exposure and the application of ototoxic substances result in increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as nitric oxide (NO). In order to reduce the free NO concentration in the inner ear under pathological conditions, the use of natural cytoprotective substances such as 17β-estradiol is a promising therapeutic concept. In male guinea pigs the organ of Corti and the lateral wall were isolated from the cochlea and afterwards incubated for 6 h in cell-culture medium. 17β-Estradiol was adjusted in 2 concentrations to organ cultures of the right ears (12 animals per concentration). The left ears were used as controls. The NO production was quantified in the supernatant by chemiluminescence after incubation. Depending on the concentration, 17β-estradiol reduced NO in the organ of Corti by 43% (p=0.015) and 46% (p=0.026), respectively. In the lateral wall, the NO concentration was reduced by 24%, but without statistical significance (p=0.86). However, when analyzing the association between the 2 cochlear regions for each animal separately, the NO concentrations were lower in nearly all 17β-estradiol-treated ears compared to controls. In order to demonstrate the flexibility of the organ culture system, the NO donor DETA NONOate and the nitric oxide synthase inhibitors L-NAME and L-NMMA were applied. The electron microscopic analysis revealed a well-preserved cochlear cell morphology after incubation. The ability of 17β-estradiol to influence the NO production preferentially in the organ of Corti might offer new therapeutic perspectives for inner ear protection.
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Affiliation(s)
- U-R Heinrich
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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Zhao LD, Li L, Wu N, Li DK, Ren LL, Guo WW, Sun JH, Liu HZ, Chen ZT, Xing GQ, Yang SM. Migration and differentiation of mouse embryonic stem cells transplanted into mature cochlea of rats with aminoglycoside-induced hearing loss. Acta Otolaryngol 2013; 133:136-43. [PMID: 23050670 DOI: 10.3109/00016489.2012.720029] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION Mouse embryonic stem cells (ESCs) transplanted into the scala tympani are able to migrate in the cochlea of rats deafened with aminoglycoside and partly restore the structure of sensory epithelia of the inner ear. OBJECTIVES To explore the migration and differentiation of enhanced green fluorescence protein (EGFP)-expressing ESCs by transplanting them into the scala tympani of rats with amikacin sulfate-induced hearing loss. METHODS Adult Sprague-Dawley (SD) rats were deafened with amikacin sulfate. Mouse ESCs expressing EGFP (EGFP-ESCs) were transplanted into the scala tympani. The migration and differentiation were observed at different time points. RESULTS EGFP-ESCs transplanted into normal cochlea did not migrate, but those in the amikacin-damaged cochlea could survive and migrate into the scala media and the vestibular cisterna. For the first time, we observed that the EGFP-ESCs migrated into the scala media, took the place of the organ of Corti, and formed a structure just like the cochlear tunnel. Some grafted stem cells even expressed myosin VIIa, the molecular marker of hair cells. Some nerve fibers reached to the bottom of the hair cell-like cells. The ESCs migrated into the vestibule and restored the sensory epithelia of the ampullary crest. The number of the transplanted ESCs reduced over the 6 week period of the study.
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Affiliation(s)
- Li-Dong Zhao
- Department of Otolaryngology-Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China
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Aron M, Victoria Akinpelu O, Dorion D, Daniel S. Otologic safety of manuka honey. J Otolaryngol Head Neck Surg 2012; 41 Suppl 1:S21-S30. [PMID: 22569046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023] Open
Abstract
OBJECTIVE To investigate the possible ototoxic effects of a 50% concentration of manuka honey in a chinchilla animal model. STUDY DESIGN A prospective, controlled animal study. SETTING The Research Institute of the Montreal Children's Hospital, McGill University Health Centre. SUBJECTS AND METHODS Eight animals had myringotomy incisions in both ears. One ear was randomly assigned to receive the 50% manuka honey solution. The contralateral ear received saline and served as the control ear. OUTCOME MEASURES Auditory brainstem evoked responses (ABRs) were measured bilaterally for a wide range of frequencies (between 8 and 25 kHz) before and 2 weeks after transtympanic manuka honey and saline application. The animals were sacrificed, and all cochleae were dissected out and processed for light and scanning electron microscopy (SEM). RESULTS The measured ABR thresholds after the application of 50% concentration of manuka honey revealed severe ototoxicity in all honey-exposed ears. This was accompanied by gross physical changes and histologic evidence of hair cell toxicity on SEM and light microscopy. The control ears remained unchanged during the period of the experiment. CONCLUSION Although 50% concentration of manuka honey is the proven concentration to have bactericidal properties against biofilms of Pseudomonas aeruginosa and Staphylococcus aureus, this concentration appeared to have caused severe or intense inflammatory changes that produced facial paralysis, vestibulotoxicity, and hearing loss.
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Affiliation(s)
- Margaret Aron
- Department of Otolaryngology Residency Program, Université de Sherbrooke, Sherbrooke, QC
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Abdala C, Dhar S, Mishra S. The breaking of cochlear scaling symmetry in human newborns and adults. J Acoust Soc Am 2011; 129:3104-3114. [PMID: 21568413 PMCID: PMC3108391 DOI: 10.1121/1.3569737] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 02/28/2011] [Accepted: 03/01/2011] [Indexed: 05/30/2023]
Abstract
Scaling symmetry appears to be a fundamental property of the cochlea as evidenced by invariant distortion product otoacoustic emission (DPOAE) phase above ∼1-1.5 kHz when using frequency-scaled stimuli. Below this frequency demarcation, phase steepens. Cochlear scaling and its breaking have been described in the adult cochlea but have not been studied in newborns. It is not clear whether immaturities in cochlear mechanics exist at birth in the human neonate. In this study, DPOAE phase was recorded with a swept-tone protocol in three, octave-wide segments from 0.5 to 4 kHz. The lowest-frequency octave was targeted with increased signal averaging to enhance signal-to-noise ratio (SNR) and focus on the apical half of the newborn cochlea where breaks from scaling have been observed. The results show: (1) the ear canal DPOAE phase was dominated by the distortion-source component in the low frequencies; thus, the reflection component cannot explain the steeper slope of phase; (2) DPOAE phase-frequency functions from adults and infants showed an unambiguous discontinuity around 1.4 and 1 kHz when described using two- and three-segment fits, respectively, and (3) newborns had a significantly steeper slope of phase in the low-frequency portion of the function which may suggest residual immaturities in the apical half of the newborn cochlea.
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Affiliation(s)
- Carolina Abdala
- Division of Communication and Auditory Neuroscience, House Research Institute, 2100 West Third Street, Los Angeles, California 90057, USA.
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Abdala C, Dhar S, Kalluri R. Level dependence of distortion product otoacoustic emission phase is attributed to component mixing. J Acoust Soc Am 2011; 129:3123-33. [PMID: 21568415 PMCID: PMC3108393 DOI: 10.1121/1.3573992] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/11/2011] [Accepted: 03/14/2011] [Indexed: 05/24/2023]
Abstract
Distortion product otoacoustic emissions (DPOAEs) measured in the ear canal represent the vector sum of components produced at two regions of the basilar membrane by distinct cochlear mechanisms. In this study, the effect of stimulus level on the 2f(1) - f(2) DPOAE phase was evaluated in 22 adult subjects across a three-octave range. Level effects were examined for the mixed DPOAE signal measured in the ear canal and after unmixing components to assess level effects individually on the distortion (generated at the f(1), f(2) overlap) and reflection (at f(dp)) sources. Results show that ear canal DPOAE phase slope becomes steeper with decreasing level; however, component analysis further explicates this result, indicating that interference between DPOAE components (rather than a shift in mechanics related to distortion generation) drives the level dependence of DPOAE phase measured in the ear canal. The relative contribution from the reflection source increased with decreasing level, producing more component interference and, at times, a reflection-dominated response at the lowest stimulus levels. These results have implications for the use of DPOAE phase to study cochlear mechanics and for the potential application of DPOAE phase for clinical purposes.
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Affiliation(s)
- Carolina Abdala
- Division of Communication and Auditory Neuroscience, House Research Institute, 2100 West Third Street, Los Angeles, California 90057, USA.
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Rodriguez J, Neely ST. Temporal aspects of suppression in distortion-product otoacoustic emissions. J Acoust Soc Am 2011; 129:3082-3089. [PMID: 21568411 PMCID: PMC3108389 DOI: 10.1121/1.3575553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/11/2011] [Accepted: 03/15/2011] [Indexed: 05/30/2023]
Abstract
This study examined the time course of cochlear suppression using a tone-burst suppressor to measure decrement of distortion-product otoacoustic emissions (DPOAEs). Seven normal-hearing subjects with ages ranging from 19 to 28 yr participated in the study. Each subject had audiometric thresholds ≤ 15 dB HL [re ANSI (2004) Specifications for Audiometers] for standard octave and inter-octave frequencies from 0.25 to 8 kHz. DPOAEs were elicited by primary tones with f(2) = 4.0 kHz and f(1) = 3.333 kHz (f(2)/f(1) = 1.2). For the f(2), L(2) combination, suppression was measured for three suppressor frequencies: One suppressor below f(2) (3.834 kHz) and two above f(2) (4.166 and 4.282 kHz) at three levels (55, 60, and 65 dB SPL). DPOAE decrement as a function of L(3) for the tone-burst suppressor was similar to decrements obtained with longer duration suppressors. Onset- and setoff- latencies were ≤ 4 ms, in agreement with previous physiological findings in auditory-nerve fiber studies that suggest suppression results from a nearly instantaneous compression of the waveform. Persistence of suppression was absent for the below-frequency suppressor (f(3) = 3.834 kHz) and was ≤ 3 ms for the two above-frequency suppressors (f(3) = 4.166 and 4.282 kHz).
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Affiliation(s)
- Joyce Rodriguez
- Starkey Hearing Research Center, 2150 Shattuck Avenue, Suite 408, Berkeley, California 94704, USA.
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Dhar S, Rogers A, Abdala C. Breaking away: violation of distortion emission phase-frequency invariance at low frequencies. J Acoust Soc Am 2011; 129:3115-22. [PMID: 21568414 PMCID: PMC3108392 DOI: 10.1121/1.3569732] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 02/25/2011] [Accepted: 02/28/2011] [Indexed: 05/26/2023]
Abstract
The phase versus frequency function of the distortion product otoacoustic emission (DPOAE) at 2f(1) - f(2) is approximately invariant at frequencies above 1.5 kHz in human subjects when recorded with a constant f(2)/f(1). However, a secular break from this invariance has been observed at lower frequencies where the phase-gradient becomes markedly steeper. Apical DPOAEs, such as 2f(1) - f(2), are known to contain contributions from multiple sources. This experiment asked whether the phase behavior of the ear canal DPOAE at low frequencies is driven by the phase of the component from the distortion product (DP) region at 2f(1) - f(2), which exhibits rapid phase accumulation. Placing a suppressor tone close in the frequency to 2f(1) - f(2) reduced the contribution of this component to the ear canal DPOAE in normal-hearing adult human ears. When the contribution of this component was reduced, the phase behavior of the ear canal DPOAE was not altered, suggesting that the breaking from DPOAE phase invariance at low frequencies is an outcome of apical-basal differences in cochlear mechanics. The deviation from DPOAE phase invariance appears to be a manifestation of the breaking from approximate scaling symmetry in the human cochlear apex.
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Affiliation(s)
- Sumitrajit Dhar
- Hugh Knowles Center, Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois 60208, USA
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Richmond SA, Kopun JG, Neely ST, Tan H, Gorga MP. Distribution of standing-wave errors in real-ear sound-level measurements. J Acoust Soc Am 2011; 129:3134-3140. [PMID: 21568416 PMCID: PMC3108394 DOI: 10.1121/1.3569726] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 02/22/2011] [Accepted: 02/26/2011] [Indexed: 05/26/2023]
Abstract
Standing waves can cause measurement errors when sound-pressure level (SPL) measurements are performed in a closed ear canal, e.g., during probe-microphone system calibration for distortion-product otoacoustic emission (DPOAE) testing. Alternative calibration methods, such as forward-pressure level (FPL), minimize the influence of standing waves by calculating the forward-going sound waves separate from the reflections that cause errors. Previous research compared test performance (Burke et al., 2010) and threshold prediction (Rogers et al., 2010) using SPL and multiple FPL calibration conditions, and surprisingly found no significant improvements when using FPL relative to SPL, except at 8 kHz. The present study examined the calibration data collected by Burke et al. and Rogers et al. from 155 human subjects in order to describe the frequency location and magnitude of standing-wave pressure minima to see if these errors might explain trends in test performance. Results indicate that while individual results varied widely, pressure variability was larger around 4 kHz and smaller at 8 kHz, consistent with the dimensions of the adult ear canal. The present data suggest that standing-wave errors are not responsible for the historically poor (8 kHz) or good (4 kHz) performance of DPOAE measures at specific test frequencies.
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Affiliation(s)
- Susan A Richmond
- Department of Speech, Language, and Hearing Sciences, The University of Arizona, Tucson, Arizona 85721, USA
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Sekerková G, Richter CP, Bartles JR. Roles of the espin actin-bundling proteins in the morphogenesis and stabilization of hair cell stereocilia revealed in CBA/CaJ congenic jerker mice. PLoS Genet 2011; 7:e1002032. [PMID: 21455486 PMCID: PMC3063760 DOI: 10.1371/journal.pgen.1002032] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 02/02/2011] [Indexed: 01/19/2023] Open
Abstract
Hearing and vestibular function depend on mechanosensory staircase collections of hair cell stereocilia, which are produced from microvillus-like precursors as their parallel actin bundle scaffolds increase in diameter and elongate or shorten. Hair cell stereocilia contain multiple classes of actin-bundling protein, but little is known about what each class contributes. To investigate the roles of the espin class of actin-bundling protein, we used a genetic approach that benefited from a judicious selection of mouse background strain and an examination of the effects of heterozygosity. A congenic jerker mouse line was prepared by repeated backcrossing into the inbred CBA/CaJ strain, which is known for excellent hearing and minimal age-related hearing loss. We compared stereocilia in wild-type CBA/CaJ mice, jerker homozygotes that lack espin proteins owing to a frameshift mutation in the espin gene, and jerker heterozygotes that contain reduced espin levels. The lack of espins radically impaired stereociliary morphogenesis, resulting in stereocilia that were abnormally thin and short, with reduced differential elongation to form a staircase. Mean stereociliary diameter did not increase beyond ∼0.10–0.14 µm, making stereocilia ∼30%–60% thinner than wild type and suggesting that they contained ∼50%–85% fewer actin filaments. These characteristics indicate a requirement for espins in the appositional growth and differential elongation of the stereociliary parallel actin bundle and fit the known biological activities of espins in vitro and in transfected cells. The stereocilia of jerker heterozygotes showed a transient proximal-distal tapering suggestive of haploinsufficiency and a slowing of morphogenesis that revealed previously unrecognized assembly steps and intermediates. The lack of espins also led to a region-dependent degeneration of stereocilia involving shortening and collapse. We conclude that the espin actin-bundling proteins are required for the assembly and stabilization of the stereociliary parallel actin bundle. Stereocilia are the fingerlike projections of inner ear hair cells that detect sound and motion. Stereocilia grow to specific lengths and diameters and form staircase-like arrays. The changes in size appear to be driven by matching alterations in the dimensions of an underlying molecular scaffold consisting of a bundle of actin filaments cross-linked by actin-bundling proteins. To elucidate the roles of the espin actin-bundling proteins in hair cell stereocilia, we carry out an in-depth accounting of stereociliary size and shape in the jerker mutant mouse, which lacks the espin proteins because of a mutation in the espin gene. We examine a new and improved jerker mouse with a genetic background known for high-quality lifelong hearing. We find that, in the absence of espins, stereocilia do not increase in diameter or complete their elongation, but instead bend, shorten, and disappear. Although the specifics vary according to inner ear region, the stereociliary defects are profound and can readily account for the deafness and balance problems of jerker mice and humans with certain espin gene mutations. Even reducing espin levels by one-half leads to temporary defects in stereociliary diameter. Thus, espins play crucial roles in the formation and maintenance of hair cell stereocilia.
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Affiliation(s)
- Gabriella Sekerková
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Claus-Peter Richter
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - James R. Bartles
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- * E-mail:
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Usami S, Takumi Y, Suzuki N, Oguchi T, Oshima A, Suzuki H, Kitoh R, Abe S, Sasaki A, Matsubara A. The localization of proteins encoded by CRYM, KIAA1199, UBA52, COL9A3, and COL9A1, genes highly expressed in the cochlea. Neuroscience 2008; 154:22-8. [PMID: 18448257 DOI: 10.1016/j.neuroscience.2008.03.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 03/08/2008] [Accepted: 03/11/2008] [Indexed: 11/25/2022]
Abstract
Genes that are highly expressed in the inner ear, as revealed by cDNA microarray analysis, may have a crucial functional role there. Those that are expressed specifically in auditory tissues are likely to be good candidates to screen for genetic alterations in patients with deafness, and several genes have been successfully identified as responsible for hereditary hearing loss. To understand the detailed mechanisms of the hearing loss caused by the mutations in these genes, the present study examined the immunocytochemical localization of the proteins encoded by Crym, KIAA1199 homolog, Uba52, Col9a3, and Col9a1 in the cochlea of rats and mice. Confocal microscopic immunocytochemistry was performed on cryostat sections. Ultrastructurally, postembedding immunogold cytochemistry was applied using Lowicryl sections. Crym protein was predominantly distributed in the fibrocytes in the spiral ligament, as well as the stria vascularis in rats. KIAA1199 protein homolog was localized in various supporting cells, including inner phalangeal, border, inner and outer pillar, and Deiters' cells. Uba52 protein was restrictedly localized within the surface of the marginal cells of the stria vascularis. Collagen type IX was found within the tectorial membrane as well as fibrocytes in the spiral ligament. The present results showed cell-specific localization of the encoded proteins of these highly expressed genes, indicating that the coordinated actions of various molecules distributed in different parts of the cochlea are essential for maintenance of auditory processing in the cochlea.
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Affiliation(s)
- S Usami
- Department of Otorhinolaryngology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan.
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Abstract
Drugs that produce tinnitus can be subdivided into those which produce temporary or permanent hearing loss and those which apparently do not cause any hearing loss. The tinnitus occurring with drugs of the first group is probably secondary to the hearing loss. However, most of the drugs that produce tinnitus without an accompanying hearing loss probably do so because of their effect on biogenic amines in the central nervous system and/or as an extension of their proconvulsant side-effects. A pre-existing cochlear impairment is the underlying factor in most patients who experience tinnitus. Not only can ototoxic drugs or high levels of noise produce cochlear impairment but the interaction of the two can place humans in more jeopardy than when exposed to either agent alone. Chloramphenicol has little ototoxic potential when administered systemically in humans. However, our studies show that when chloramphenicol is combined with noise exposure in rats, considerably more cochlear damage results than from the noise alone (chloramphenicol alone does no produce any cochlear damage). We are presently conducting more detailed studies of this ototoxic interaction to determine whether it occurs with other antibiotics (such as erythromycin) which are also commonly considered to have minimal ototoxicity.
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Markaryan A, Nelson EG, Hinojosa R. Detection of mitochondrial DNA deletions in the cochlea and its structural elements from archival human temporal bone tissue. Mutat Res 2008; 640:38-45. [PMID: 18242646 DOI: 10.1016/j.mrfmmm.2007.12.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2007] [Revised: 09/10/2007] [Accepted: 12/11/2007] [Indexed: 05/25/2023]
Abstract
Large-scale deletions of mitochondrial DNA (mtDNA) have been associated with aging and disease in post-mitotic tissues. These post-mitotic tissues, including skeletal muscle, heart and brain, are heavily dependent on intact functional mitochondria. The cochlear tissues are known to contain an abundance of mitochondria. This observation stimulated a search for mtDNA deletions in the cochlea and its elements using a sensitive nested PCR methodology and long range PCR to explain the functional deficits observed in age-related hearing loss. The presence of the so-called "common" deletion (CD) was detected in cochlear tissue from two individuals with age-related hearing loss, 73 and 78 years of age. Three additional deletions, that to our knowledge have not been previously reported, were also identified in these two individuals, including a 5354 bp deletion flanked with a 3 bp repeat, a 9682 bp deletion flanked by a 10 bp repeat and a 5142 bp deletion without a flanking repeat. The 9682 and 5142 bp deletions were also detected in an individual 39 years of age with normal hearing, however, these two deletions were not detected in a normal hearing individual 9 years of age. In contrast, the 5354 bp deletion was detected in all four of the individuals studied. To localize the deletions within the cochlea, the cochlear elements were removed by laser capture microdissection (LCM) and the mtDNA from these tissues was studied. The 5142 and 5354 bp deletions were detected in the organ of corti, spiral ligament, and ganglion cells, but not in the stria vascularis. These findings correlate with the reduction in the number of spiral ganglion cells and outer hair cells, and the normal stria vascularis volume observed in this individual. All four of these deletions involve the cytochrome c oxidase (COX) subunit III gene, encoded by mtDNA. These observations suggest that multiple mtDNA deletions may contribute to a deficit in mitochondrial function in the cochlea and result in hearing loss if a level of physiological significance is reached.
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Affiliation(s)
- Adam Markaryan
- Section Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Chicago, 5841 South Maryland Avenue, MC 1035, Chicago, IL 60637, United States.
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41
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Zhang YS, Zhang YH, Xiao DJ. [Morphological observation of cochlear pathological changes in diabetic SD rats]. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2008; 43:64-66. [PMID: 18357718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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42
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Ge X, Jackson RL, Liu J, Harper EA, Hoffer ME, Wassel RA, Dormer KJ, Kopke RD, Balough BJ. Distribution of PLGA nanoparticles in chinchilla cochleae. Otolaryngol Head Neck Surg 2007; 137:619-23. [PMID: 17903580 DOI: 10.1016/j.otohns.2007.04.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Accepted: 04/19/2007] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To study the distribution of polylactic/glycolic acid-encapsulated iron oxide nanoparticles (PLGA-NPs) in chinchilla cochleae after application on the round window membrane (RWM). STUDY DESIGN AND SETTING Six chinchillas (12 ears) were equally divided into controls (no treatments) and experimentals (PLGA-NP with or without magnetic exposure). After 40 minutes of PLGA-NP placement on the RWM, perilymph was withdrawn from the scala tympani. The RWM and cochleae were fixed with 2.5% glutaraldehyde and processed for transmission electron microscopy. RESULTS Nanoparticles were found in cochleae with or without exposure to magnet forces appearing in the RWM, perilymph, endolymph, and multiple locations in the organ of Corti. Electron energy loss spectroscopy confirmed iron elements in nanoparticles. CONCLUSION The nanoparticles were distributed throughout the inner ear after application on the chinchilla RWM, with and without magnetic forces. SIGNIFICANCE PLGA-NP applied to the RWM may have potential for sustained therapy to the inner ear.
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Affiliation(s)
- Xianxi Ge
- Spatial Orientation Center, Department of Otolaryngology, Naval Medical Center San Diego, San Diego, CA 92134-5000, USA.
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Gocer C, Eryilmaz A, Kayikci MEK, Korkmaz H, Surucu S, Akmansu SH. Functional and morphological effects of fotemustine on the auditory system of the rat. J Laryngol Otol 2007; 122:551-6. [PMID: 17888195 DOI: 10.1017/s0022215107000369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE This study aimed to elucidate the potential inner-ear effects of fotemustine, a chemotherapeutic agent which crosses the blood-brain barrier and is used in the treatment of primary and metastatic brain tumours and metastatic melanoma. METHODS This study utilised distortion product otoacoustic emissions and transmission electron microscopy in order to conduct electrophysiological and morphological assessments, using a rat experimental model. Twelve ears of six male rats were examined two months following intraperitoneal slow infusion of fotemustine (100 mg/m2 or 7.4 mg/kg). Pre- and post-treatment measurements were compared. Finally, electron microscopy was performed on three rat temporal bones. RESULTS After infusion of fotemustine, distortion product otoacoustic emissions revealed a significant reduction in signal-to-noise ratios only at 3600 Hz (from 11.95 +/- 7.52 to -0.26 +/- 9.45 dB) and at 3961 Hz (from 18.09 +/- 7.49 to 6.74 +/- 12.11 dB) (referenced to 2f1 - f2). Transmission electron microscopy of the temporal bone revealed ultrastructural changes in the outer hair cells, stria vascularis and cochlear ganglion at the cochlear basal turn. The ganglion cell perikarya were unaffected. CONCLUSIONS Fotemustine was administered via intraperitoneal slow infusion in a rat experimental model. Twelve ears of six survivors, from 10 rats, were evaluated at the second month. Fotemustine was determined to have a potential for ototoxicity at 3600 and 3961 Hz. Three randomly chosen rats underwent electron microscopy for morphological analysis. Morphological effects in the cochlear basal turn were observed. Oedematous intracytoplasmic spaces and perivascular areas of the stria vascularis, as well as distorted chromatin content, were detected, thereby suggesting potential ototoxic effects for this agent. Further experimental and clinical studies are required in order to determine whether the effect seen in this pilot study is reversible, and to analyse effects in humans.
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Affiliation(s)
- C Gocer
- Department of Otorhinolaryngology, Ankara Numune Hospital, Turkey.
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Mogensen MM, Rzadzinska A, Steel KP. The deaf mouse mutant whirler suggests a role for whirlin in actin filament dynamics and stereocilia development. ACTA ACUST UNITED AC 2007; 64:496-508. [PMID: 17326148 PMCID: PMC2682331 DOI: 10.1002/cm.20199] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Stereocilia, finger-like projections forming the hair bundle on the apical surface of sensory hair cells in the cochlea, are responsible for mechanosensation and ultimately the perception of sound. The actin cytoskeleton of the stereocilia contains hundreds of tightly cross-linked parallel actin filaments in a paracrystalline array and it is vital for their function. Although several genes have been identified and associated with stereocilia development, the molecular mechanisms responsible for stereocilia growth, maintenance and organisation of the hair bundle have not been fully resolved. Here we provide further characterisation of the stereocilia of the whirler mouse mutant. We found that a lack of whirlin protein in whirler mutants results in short stereocilia with larger diameters without a corresponding increase in the number of actin filaments in inner hair cells. However, a decrease in the actin filament packing density was evident in the whirler mutant. The electron-density at the tip of each stereocilium was markedly patchy and irregular in the whirler mutants compared with a uniform band in controls. The outer hair cell stereocilia of the whirler homozygote also showed an increase in diameter and variable heights within bundles. The number of outer hair cell stereocilia was significantly reduced and the centre-to-centre spacing between the stereocilia was greater than in the wildtype. Our findings suggest that whirlin plays an important role in actin filament packing and dynamics during postnatal stereocilium elongation.
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MESH Headings
- Actin Cytoskeleton/genetics
- Actin Cytoskeleton/metabolism
- Animals
- Cilia/metabolism
- Cilia/ultrastructure
- Cochlea/metabolism
- Cochlea/ultrastructure
- Deafness/genetics
- Deafness/metabolism
- Ear, Inner/metabolism
- Ear, Inner/ultrastructure
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/ultrastructure
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/ultrastructure
- Homozygote
- Intercellular Signaling Peptides and Proteins
- Membrane Proteins/genetics
- Membrane Proteins/physiology
- Mice
- Mice, Mutant Strains
- Microscopy, Electron, Scanning
- Mutation
- Proteins/genetics
- Proteins/metabolism
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Affiliation(s)
- Mette M Mogensen
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom.
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Abstract
HYPOTHESIS A standardized Ginkgo biloba extract, EGb 761, may have protective effect against cisplatin-induced ototoxicity in rats. BACKGROUND Cisplatin-induced ototoxicity is a major dose-limiting side effect in anticancer chemotherapy. Cisplatin-induced ototoxicity has been correlated to depletion of the cochlear antioxidant system and increased lipid peroxidation. EGb 761 contains potent antioxidants capable of scavenging free radicals, inhibiting nitric oxide synthesis, reducing lipid peroxidation, and protecting against apoptosis. The purpose of this study was to investigate the effect of EGb 761 on cisplatin-induced ototoxicity in rats. METHODS Male Wistar rats were divided into four groups and were treated as follows: 1) vehicle control; 2) cisplatin (13 mg/kg, intraperitoneally) plus vehicle; 3) EGb 761 (200 mg/kg, intraperitoneally); and 4) EGb 761 plus cisplatin. Auditory brainstem responses (ABRs) were measured pretreatment and 72 hours posttreatment, and threshold shifts were analyzed. Endocochlear potentials (EPs) were also obtained at 72 hours posttreatment. Cochleae were harvested and processed for scanning electron microscopy after completion of auditory testing. RESULTS Cisplatin-treated rats showed significant ABR threshold shifts across all frequencies (click, and 2-, 4-, 8-, 16-, and 32-kHz tones) compared with each of the other groups (p < 0.001). Rats treated with EGb 761 plus cisplatin did not show significant ABR threshold shifts (p > 0.05). Similarly, the EPs of cisplatin-treated rats were decreased significantly approximately 50% in comparison with the other groups (p < 0.001). The EPs of EGb 761 plus cisplatin-treated rats were decreased less than 20% compared with vehicle control group or the EGb 761 only group (p < 0.01). The scanning electron microscopy observation indicated severe outer hair cell loss in the basal turn of cochleae of cisplatin-treated rats, whereas outer hair cells remained intact in the rats treated with EGb 761 plus cisplatin. CONCLUSION These results demonstrate that EGb 761 protects against cisplatin-induced ototoxicity.
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MESH Headings
- Animals
- Antineoplastic Agents/toxicity
- Cisplatin/toxicity
- Cochlea/pathology
- Cochlea/ultrastructure
- Cochlear Microphonic Potentials
- Evoked Potentials, Auditory, Brain Stem/physiology
- Ginkgo biloba
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Inner/ultrastructure
- Hair Cells, Auditory, Outer/pathology
- Hair Cells, Auditory, Outer/ultrastructure
- Hearing Disorders/chemically induced
- Hearing Disorders/prevention & control
- Male
- Microscopy, Electron, Scanning
- Phytotherapy
- Plant Extracts/therapeutic use
- Rats
- Rats, Wistar
- Temporal Bone/pathology
- Temporal Bone/ultrastructure
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Affiliation(s)
- Xinyan Huang
- Division of Otolaryngology Head & Neck Surgery, Southern Illinois University School of Medicine, Springfield, Illinois 62794-9662, USA
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Minoda R, Izumikawa M, Kawamoto K, Zhang H, Raphael Y. Manipulating cell cycle regulation in the mature cochlea. Hear Res 2007; 232:44-51. [PMID: 17658230 PMCID: PMC2048570 DOI: 10.1016/j.heares.2007.06.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 06/06/2007] [Accepted: 06/08/2007] [Indexed: 11/19/2022]
Abstract
Sensorineural hearing loss, which is often caused by degeneration of hair cells in the auditory epithelium, is permanent because lost hair cells are not replaced. Several conceptual approaches can be used to place new hair cells in the auditory epithelium. One possibility is to enhance proliferation of non-sensory cells that remain in the deaf ear and induce transdifferentiation of some of these cells into the hair cell phenotype. Several genes, including p27(Kip1), have been shown to regulate proliferation and differentiation in the developing auditory epithelium. The role of p27(Kip1) in the mature ear is not well characterized. We now show that p27(Kip1) is present in the nuclei of non-sensory cells of the mature auditory epithelium. We determined that forced expression of Skp2 using a recombinant adenovirus vector, resulted in presence of BrdU-positive cells in the auditory epithelium. When SKP2 over-expression was combined with forced expression of Atoh1, ectopic hair cells were found in the auditory epithelium in greater numbers than were seen with Atoh1 alone. Skp2 over-expression alone did not result in ectopic hair cells. These findings suggest that the p27(Kip1) protein remains in the mature auditory epithelium and therefore p27(Kip1) can serve as a target for gene manipulation. The data also suggest that induced proliferation, by itself, does not generate new hair cells in the cochlea.
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Affiliation(s)
- Ryosei Minoda
- Kresge Hearing Research Institute, The University of Michigan, MSRB 3, Rm. 9303, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-0648, USA
- Department of Otolaryngology- Head and Neck Surgery, Kumamoto University School of Medicine, 1-1-1 Honjo Kumamoto 860-8556, Japan
| | - Masahiko Izumikawa
- Kresge Hearing Research Institute, The University of Michigan, MSRB 3, Rm. 9303, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-0648, USA
- Department of Otolaryngology- Head and Neck Surgery, Kansai Medical University, 10-15 Fumizono-cho, Moriguchi, Osaka 570-8506, Japan
| | - Kohei Kawamoto
- Kresge Hearing Research Institute, The University of Michigan, MSRB 3, Rm. 9303, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-0648, USA
- Department of Otolaryngology- Head and Neck Surgery, Kansai Medical University, 10-15 Fumizono-cho, Moriguchi, Osaka 570-8506, Japan
| | - Hui Zhang
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, P.O. Box 208005, New Haven, CT 06520-8005, USA
| | - Yehoash Raphael
- Kresge Hearing Research Institute, The University of Michigan, MSRB 3, Rm. 9303, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-0648, USA
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Ruan Q, Wang D, Gao H, Liu A, Da C, Yin S, Chi F. The effects of different auditory activity on the expression of phosphorylated c-Jun in the auditory system. Acta Otolaryngol 2007; 127:594-604. [PMID: 17503228 DOI: 10.1080/00016480600951459] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
CONCLUSION The data revealed that calcium influx via the NMDA receptor up-regulated the expression of phosphorylated c-Jun in the primary auditory cortices following sensory stimulation and after different neural injury stimulations which guide activity-dependent changes in gene expression and neural plasticity. OBJECTIVES Activator protein-1 (AP-1) transcription factor, which is mainly composed of c-Fos and c-Jun proteins, is believed to be a key participant in molecular processes that guide activity-dependent changes in gene expression. Our previous study had shown that the expression of NMDAR2A gene on synaptosomes membrane of auditory cortical neurons varied by electrical intracochlear stimulation (EIS) and neural injury induced by acoustic trauma. In this study, we investigated the role of the NMDA receptor (NMDAR) in regulating the expression of phosphorylated c-Jun in the primary auditory cortex (AI). The modulation factors observed for gene expression included EIS and noise traumas. MATERIALS AND METHODS EIS was applied in rats with early postnatal auditory deprivation. The impact of the noise traumas on the ultrastructures of spiral ganglion neurons (SGNs) and their innervations to inner hair cells (IHCs) were verified by transmission electron microscopy (EM). These changes include a decrease in subcellular organelles, the swelling of mitochondria and endoplasmic reticulum, the morphological changes in cell nuclei, and damage in the afferent synapse. RESULTS Immunohistochemistry observations showed that the expression of phosphorylated c-jun and active caspase-3 in hair cells and SGNs varied with amount of noise. Immunocytochemistry and Western blotting showed that the auditory cortex began to express phosphorylated c-jun 24 h after 2 h of EIS. However, this expression was not changed by EIS if NMDAR antagonist was applied. The level of phosphorylated c-Jun was remarkably increased in AI after noise overstimulation at 115 dB SPL for 3 h. Again, such an increase was not seen if NMDAR antagonist 3-(2 carboxypiperazin-4yl) propyl-1-phosphonic acid (CPP, 10 mg/kg, i.p.) was applied 30 min before the noise exposure.
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MESH Headings
- Animals
- Auditory Cortex/pathology
- Auditory Cortex/physiology
- Auditory Pathways/physiology
- Auditory Threshold/physiology
- Blotting, Western
- Caspase 3/metabolism
- Cochlea/metabolism
- Cochlea/ultrastructure
- Electric Stimulation
- Electrodes, Implanted
- Evoked Potentials, Auditory, Brain Stem/physiology
- Excitatory Amino Acid Antagonists/pharmacology
- Female
- Genes, jun
- Hearing Loss, Noise-Induced/genetics
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/pathology
- Male
- Microscopy, Electron
- Neuronal Plasticity/physiology
- Phosphorylation
- Piperazines/pharmacology
- Proto-Oncogene Proteins c-jun/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/metabolism
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Affiliation(s)
- Qingwei Ruan
- Otolaryngology Research Institute, Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, PR China
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da Silva JG, Hyppolito MA, de Oliveira JAA, Corrado AP, Ito IY, Carvalho I. Aminoglycoside antibiotic derivatives: Preparation and evaluation of toxicity on cochlea and vestibular tissues and antimicrobial activity. Bioorg Med Chem 2007; 15:3624-34. [PMID: 17416529 DOI: 10.1016/j.bmc.2007.03.056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 03/15/2007] [Accepted: 03/18/2007] [Indexed: 11/30/2022]
Abstract
Aminoglycoside antibiotic derivatives such as neamine, methyl neobiosaminide B, 2-deoxystreptamine, tetra-azidoneamine, tetra-N-acetylneamine, tetra-N-carboxy-benzylneamine, tetra-N-carboxy-methylneamine and tetra-p-methoxy-benzyliminoneamine were prepared and evaluated as to their cochlear and vestibular toxicity. Methyl neobiosaminide B, the most promising derivative in the series showed selective, cochlea-dissociated vestibulotoxic activity and was considered to be a potential lead compound for the treatment of Ménière's disease. Antimicrobial properties of the compounds, qualitatively evaluated against a group of pathogenic bacteria, indicated that neomycin B sulfate, neamine as a free base and methyl-neobiosaminide B dihydrochloride show a broader range of activity when compared to the other derivatives.
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Affiliation(s)
- Julierme G da Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café s/n, 14040-903 Ribeirão Preto-SP, Brazil
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Hayashi H, Sone M, Schachern PA, Wakamatsu K, Paparella MM, Nakashima T. Comparison of the quantity of cochlear melanin in young and old C57BL/6 mice. ACTA ACUST UNITED AC 2007; 133:151-4. [PMID: 17309984 DOI: 10.1001/archotol.133.2.151] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To elucidate the functional relationship between cochlear melanin and aging. DESIGN Melanin has been described in the cochlear labyrinth and has been suggested to protect the cochlea from various types of trauma. The quantity of melanin has been shown to change with aging in several organs; however, to our knowledge, aging changes in the cochlea have not been documented. Therefore, we chemically quantified cochlear eumelanin and pheomelanin contents and compared these in young and old C57BL/6 mice using high-performance liquid chromatography. Because melanin deposits in the cochlea present most extensively in the stria vascularis, we morphologically examined the stria using transmission electron microscopy. SUBJECTS Cochleae from an inbred strain of C57BL/6 male and female mice; 6 at the age of 10 weeks and 5 at the age of 100 weeks were studied. RESULTS The quantities of cochlear eumelanin and pheomelanin were 421 and 480 ng per cochlea in young mice, and 2060 and 765 ng per cochlea in old mice, respectively. Under transmission electron microscopy, the number of pigmented granules seemed to be greater in older mice compared with younger mice, especially in marginal cells. CONCLUSION To our knowledge, our findings are the first quantitative evidence to show an age-related overexpression of cochlear melanin and an alteration in the proportion of eumelanin and pheomelanin with aging, suggesting a possible otoprotective function of eumelanin against age-related cochlear deterioration.
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Affiliation(s)
- Hideo Hayashi
- Department of Otorhinolaryngology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Morita Y, Hirokawa S, Kikkawa Y, Nomura T, Yonekawa H, Shiroishi T, Takahashi S, Kominami R. Fine mapping of Ahl3 affecting both age-related and noise-induced hearing loss. Biochem Biophys Res Commun 2007; 355:117-21. [PMID: 17291455 DOI: 10.1016/j.bbrc.2007.01.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Accepted: 01/23/2007] [Indexed: 11/29/2022]
Abstract
A region in the vicinity of D17Mit119 on mouse chromosome 17 harbors a susceptibility gene, designated as Ahl3, to age-related hearing loss (AHL). We produced congenic lines of C57BL/6 background that substituted regions around D17Mit119 with MSM-derived ones, and examined auditory brainstem response (ABR) thresholds for their hearing capacity at 6 and 12months of age. Three congenic lines carrying the approximately 14-Mb region between D17Mit274 and D17Mit183 retained normal hearing at 12months of age whereas two congenic lines not carrying this region tended to lose hearing at that age. We also investigated noise-induced hearing loss (NIHL) in congenic lines at 1, 7 and 14days after exposure to the noise of 100dB for 1h. Most congenic mice carrying the 14-Mb region did not exhibit permanent threshold shift (PTS) whereas mice not carrying this region exhibited a strong tendency of PTS, indicating the role of Ahl3 in susceptibility to NIHL. These results indicate that Ahl3 exists within the 14-Mb region and affects not only AHL but also NIHL.
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Affiliation(s)
- Yuka Morita
- Department of Molecular Genetics, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510, Japan
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