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Vogl C, Neef J, Wichmann C. Methods for multiscale structural and functional analysis of the mammalian cochlea. Mol Cell Neurosci 2022; 120:103720. [DOI: 10.1016/j.mcn.2022.103720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 02/13/2022] [Accepted: 03/08/2022] [Indexed: 01/11/2023] Open
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Mishra S, Roy T, Saini S. Development of the hair cells of the human cochlea: A scanning electron microscopic study. J Microsc Ultrastruct 2022; 11:17-22. [PMID: 37144166 PMCID: PMC10153736 DOI: 10.4103/jmau.jmau_107_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/26/2020] [Accepted: 12/01/2020] [Indexed: 11/04/2022] Open
Abstract
Introduction In the mammalian auditory system, the cochlea is the first to attain structural and functional maturity. Although ultrastructural details of the developing cochlea of lower animals have been elucidated in the last few decades, comprehensive studies on human cochlea are lacking. Materials and Methods In the present investigation we studied the development and maturation of the hair cells of ten human fetal cochlea from gestational weeks (GW) 12 to 37 by scanning electron microscopy. Result We observed undifferentiated hair cells possessing numerous surface projections and long kinocilium during GW 14. At GW16, the primitive hair cells were arranged in one inner and four outer rows and had globular apices indicating the initiation of stereocilia formation. By GW 22, the globular apices were replaced by linear stereocilia and occasional kinocillia. Mature hair cells with sterocilia were observed in the basal turn at 30th week of gestation. At GW 37, the stereocilia were arranged in a typical "V" shaped pattern at the middle and apical coil, while the stereocilia of the basal turn were shorter in length resembling the adult cochlea. The inner hair cells were long and slender while outer hair cells were pear shaped, kinocilium were absent and the tunnel of Corti were well formed. Conclusion It is concluded that in human, the morphological maturation of the hair cells starts in the basal turn around GW 22 and continues till 37th week in the apical turn indicating that early maturation of the cochlea may have a role on development of the higher auditory pathway connections.
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Morell M, IJsseldijk LL, Piscitelli-Doshkov M, Ostertag S, Estrade V, Haulena M, Doshkov P, Bourien J, Raverty SA, Siebert U, Puel JL, Shadwick RE. Cochlear apical morphology in toothed whales: Using the pairing hair cell-Deiters' cell as a marker to detect lesions. Anat Rec (Hoboken) 2021; 305:622-642. [PMID: 34096183 DOI: 10.1002/ar.24680] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 03/17/2021] [Accepted: 04/15/2021] [Indexed: 11/06/2022]
Abstract
The apex or apical region of the cochlear spiral within the inner ear encodes for low-frequency sounds. The disposition of sensory hair cells on the organ of Corti is largely variable in the apical region of mammals, and it does not necessarily follow the typical three-row pattern of outer hair cells (OHCs). As most underwater noise sources contain low-frequency components, we expect to find most lesions in the apical region of the cochlea of toothed whales, in cases of permanent noise-induced hearing loss. To further understand how man-made noise might affect cetacean hearing, there is a need to describe normal morphological features of the apex and document interspecific anatomic variations in cetaceans. However, distinguishing between apical normal variability and hair cell death is challenging. We describe anatomical features of the organ of Corti of the apex in 23 ears from five species of toothed whales (harbor porpoise Phocoena phocoena, spinner dolphin Stenella longirostris, pantropical spotted dolphin Stenella attenuata, pygmy sperm whale Kogia breviceps, and beluga whale Delphinapterus leucas) by scanning electron microscopy and immunofluorescence. Our results showed an initial region where the lowest frequencies are encoded with two or three rows of OHCs, followed by the typical configuration of three OHC rows and three rows of supporting Deiters' cells. Whenever two rows of OHCs were detected, there were usually only two corresponding rows of supporting Deiters' cells, suggesting that the number of rows of Deiters' cells is a good indicator to distinguish between normal and pathological features.
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Affiliation(s)
- Maria Morell
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany.,Institute for Neurosciences of Montpellier, University of Montpellier, INSERM Unit 1051, Montpellier, France.,Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lonneke L IJsseldijk
- Division of Pathology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | | | - Sonja Ostertag
- School of Public Health, University of Waterloo, Waterloo, Ontario, Canada.,Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | | | - Martin Haulena
- Vancouver Aquarium Marine Science Center, Vancouver, British Columbia, Canada
| | - Paul Doshkov
- Cape Hatteras National Seashore, Manteo, North Carolina, USA
| | - Jérôme Bourien
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM Unit 1051, Montpellier, France
| | - Stephen A Raverty
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada.,Animal Health Center, Animal Health Center, Ministry of Agriculture, Abbotsford, British Columbia, Canada
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany
| | - Jean-Luc Puel
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM Unit 1051, Montpellier, France
| | - Robert E Shadwick
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada
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Chi T, Liu M, Tan X, Li Y, Xiao Y, Sun K, Jin L, Feng J. Vocal Development of Horsfield's Leaf-Nosed Bat Pups (Hipposideros larvatus). ACTA CHIROPTEROLOGICA 2019. [DOI: 10.3161/15081109acc2019.21.1.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Tingting Chi
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130024, China
| | - Muxun Liu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130024, China
| | - Xiao Tan
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130024, China
| | - Yu Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130024, China
| | - Yanhong Xiao
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130024, China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130024, China
| | - Longru Jin
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130024, China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130024, China
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Selective ablation of pillar and deiters' cells severely affects cochlear postnatal development and hearing in mice. J Neurosci 2013; 33:1564-76. [PMID: 23345230 DOI: 10.1523/jneurosci.3088-12.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Mammalian auditory hair cells (HCs) are inserted into a well structured environment of supporting cells (SCs) and acellular matrices. It has been proposed that when HCs are irreversibly damaged by noise or ototoxic drugs, surrounding SCs seal the epithelial surface and likely extend the survival of auditory neurons. Because SCs are more resistant to damage than HCs, the effects of primary SC loss on HC survival and hearing have received little attention. We used the Cre/loxP system in mice to specifically ablate pillar cells (PCs) and Deiters' cells (DCs). In Prox1CreER(T2)+/-;Rosa26(DTA/+) (Prox1DTA) mice, Cre-estrogen receptor (CreER) expression is driven by the endogenous Prox1 promoter and, in presence of tamoxifen, removes a stop codon in the Rosa26(DTA/+) allele and induces diphtheria toxin fragment A (DTA) expression. DTA produces cell-autonomous apoptosis. Prox1DTA mice injected with tamoxifen at postnatal days 0 (P0) and P1 show significant DC and outer PC loss at P2-P4, that reaches ∼70% by 1 month. Outer HC loss follows at P14 and is almost complete at 1 month, while inner HCs remain intact. Neural innervation to the outer HCs is disrupted in Prox1DTA mice and auditory brainstem response thresholds in adults are 40-50 dB higher than in controls. The hearing deficit correlates with loss of cochlear amplification. Remarkably, in Prox1DTA mice, the auditory epithelium preserves the ability to seal the reticular lamina and spiral ganglion neuron counts are normal, a key requirement for cochlear implant success. In addition, our results show that cochlear SC pools should be appropriately replenished during HC regeneration strategies.
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Auditory and vestibular hair cell stereocilia: relationship between functionality and inner ear disease. The Journal of Laryngology & Otology 2011; 125:991-1003. [PMID: 21774850 DOI: 10.1017/s0022215111001459] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The stereocilia of the inner ear are unique cellular structures which correlate anatomically with distinct cochlear functions, including mechanoelectrical transduction, cochlear amplification, adaptation, frequency selectivity and tuning. Their function is impaired by inner ear stressors, by various types of hereditary deafness, syndromic hearing loss and inner ear disease (e.g. Ménière's disease). The anatomical and physiological characteristics of stereocilia are discussed in relation to inner ear malfunctions.
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Simmons DD, Tong B, Schrader AD, Hornak AJ. Oncomodulin identifies different hair cell types in the mammalian inner ear. J Comp Neurol 2010; 518:3785-802. [PMID: 20653034 DOI: 10.1002/cne.22424] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The tight regulation of Ca(2+) is essential for inner ear function, and yet the role of Ca(2+) binding proteins (CaBPs) remains elusive. By using immunofluorescence and reverse transcriptase-polymerase chain reaction (RT-PCR), we investigated the expression of oncomodulin (Ocm), a member of the parvalbumin family, relative to other EF-hand CaBPs in cochlear and vestibular organs in the mouse. In the mouse cochlea, Ocm is found only in outer hair cells and is localized preferentially to the basolateral outer hair cell membrane and to the base of the hair bundle. Developmentally, Ocm immunoreactivity begins as early as postnatal day (P) 2 and shows preferential localization to the basolateral membrane and hair bundle after P8. Unlike the cochlea, Ocm expression is substantially reduced in vestibular tissues at older adult ages. In vestibular organs, Ocm is found in type I striolar or central hair cells, and has a more diffuse subcellular localization throughout the hair cell body. Additionally, Ocm immunoreactivity in vestibular hair cells is present as early as E18 and is not obviously affected by mutations that cause a disruption of hair bundle polarity. We also find Ocm expression in striolar hair cells across mammalian species. These data suggest that Ocm may have distinct functional roles in cochlear and vestibular hair cells.
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Affiliation(s)
- Dwayne D Simmons
- Department of Integrative Biology and Physiology and the Brain Research Institute, University of California Los Angeles, Los Angeles, California 90095, USA.
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Ramírez-Camacho R, García-Berrocal JR, Trinidad A, González-García JA, Verdaguer JM, Ibáñez A, Rodríguez A, Sanz R. Central role of supporting cells in cochlear homeostasis and pathology. Med Hypotheses 2006; 67:550-5. [PMID: 16632231 DOI: 10.1016/j.mehy.2006.02.044] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Accepted: 02/20/2006] [Indexed: 10/24/2022]
Abstract
HYPOTHESIS Supporting cells have a crucial role in degenerative and regenerative events of primary sensorial hair cells of the organ of Corti. This new role should determine future studies about pathophysiology of hearing loss and its regenerative treatment. SUPPORTING EVIDENCE Recent findings suggest an active role of supporting cells in the maintenance of hair cell function and structure. Evidences of high energy consumption and close proximity to auditory nervous fibers suggesting K+ active exchange, preferential expression of specific proteins and antigens, presence of glucocorticoids receptors, affinity for cisplatin and regenerative potential give the supporting cells an important role in homeostasis of the organ of Corti and in some specific diseases affecting this structure. CONCLUSION As well as glial cells provide protection and regeneration to neural tissues, supporting cells may provide the necessary metabolic and electrolitic conditions for hair cells mechanical and bioelectrical function. This opens new possibilities for the treatment of apparently "irreversible" destruction of the inner ear.
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Affiliation(s)
- R Ramírez-Camacho
- Ear Research Group, Hospital Universitario Puerta de Hierro, Universidad Autónoma de Madrid, San Martín de Porres 4, 28035 Madrid, Spain
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Kössl M, Foeller E, Drexl M, Vater M, Mora E, Coro F, Russell IJ. Postnatal Development of Cochlear Function in the Mustached Bat,Pteronotus parnellii. J Neurophysiol 2003; 90:2261-73. [PMID: 14534266 DOI: 10.1152/jn.00100.2003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Postnatal development of the mustached bat's cochlea was studied by measuring cochlear microphonic and compound action potentials. In adults, a cochlear resonance is involved in enhanced tuning to the second harmonic constant frequency component (CF2) of their echolocation calls at ∼61 kHz This resonance is present immediately after birth in bats that do not yet echolocate. Its frequency is lower (46 kHz) and the corresponding threshold minimum of cochlear microphonic potentials is broader than in adults. Long-lasting ringing of the cochlear microphonic potential after tone stimulus offset that characterizes the adult auditory response close to CF2 is absent in newborns. In the course of the first 5 postnatal weeks, there is a concomitant upward shift of CF2 and the frequency of cochlear threshold minima. Up to the end of the third postnatal week, sensitivity of auditory threshold minima and the Q value of the cochlear resonance increase at a fast rate. Between 2 and 4 wk of age, two cochlear microphonic threshold minima are found consistently in the CF2 range that differ in their level-dependent dynamic growth behavior and are 1.5–5.7 kHz apart from each other. In older animals, there is a single minimum that approaches adult tuning in its sharpness. The data provide evidence to show that during maturation of the cochlea, the frequency and the sensitivity of the threshold minimum associated with CF2 increases and that these increases are associated with the fusion of two resonances that are partly dissociated in developing animals.
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Affiliation(s)
- M Kössl
- Zoological Institute, University of Frankfurt, 60323 Frankfurt am Main, Germany.
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Abstract
The role of the cochlea is to transduce complex sound waves into electrical neural activity in the auditory nerve. Hair cells of the organ of Corti are the sensory cells of hearing. The inner hair cells perform the transduction and initiate the depolarization of the spiral ganglion neurons. The outer hair cells are accessory sensory cells that enhance the sensitivity and selectivity of the cochlea. Neural feedback loops that bring efferent signals to the outer hair cells assist in sharpening and amplifying the signals. The stria vascularis generates the endocochlear potential and maintains the ionic composition of the endolymph, the fluid in which the apical surface of the hair cells is bathed. The mechanical characteristics of the basilar membrane and its related structures further enhance the frequency selectivity of the auditory transduction mechanism. The tectorial membrane is an extracellular matrix, which provides mass loading on top of the organ of Corti, facilitating deflection of the stereocilia. This review deals with the structure of the normal mature mammalian cochlea and includes recent data on the molecular organization of the main cell types within the cochlea.
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Affiliation(s)
- Yehoash Raphael
- Kresge Hearing Research Institute, The University of Michigan, MSRB 3, Rm 9303, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-0648, USA.
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Pujol R, Lavigne-Rebillard M, Lenoir M. Development of Sensory and Neural Structures in the Mammalian Cochlea. DEVELOPMENT OF THE AUDITORY SYSTEM 1998. [DOI: 10.1007/978-1-4612-2186-9_4] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Kuhn B, Vater M. The postnatal development of F-actin in tension fibroblasts of the spiral ligament of the gerbil cochlea. Hear Res 1997; 108:180-90. [PMID: 9213130 DOI: 10.1016/s0378-5955(97)00051-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The tension fibroblasts of the spiral ligament of the mammalian cochlea are thought to create radial tension on the basilar membrane. Their postnatal development was investigated in the gerbil (Meriones unguiculatus) with confocal fluorescence microscopy using phallotoxin as a specific marker for F-actin. In the adult cochlea, tension fibroblasts were restricted to the basal cochlear turn and were arranged in 2-4 rows in the marginal region of the spiral ligament. They contained intensely stained parallel bundles of F-actin. In upper cochlear turns, the marginal region of the spiral ligament was occupied by sparsely distributed, unobtrusively labeled fibrocytes, the bone lining cells. The spiral ligament of young postnatal stages (newborn--6 days after birth (DAB)) lacked F-actin labeling patterns that are characteristic for tension fibroblasts in the adult. Rather, the whole inner surface of the otic capsule throughout all cochlear turns was outlined by cell layers with distinct but diffuse cytoplasmic F-actin label. These cells may represent perichondrial fibrocytes. Around 9 DAB, the perichondrium revealed changes in morphology and F-actin patterns that indicate a further differentiation into tension fibroblasts (basal turn) or bone lining cells (more apical turns). At 12 DAB, around onset of hearing, adult-like bone lining cells were found in the marginal regions of the spiral ligament of upper cochlear turns. In the basal turn, tension fibroblasts were present, but their F-actin cytoskeleton was not fully developed. During the following days, F-actin label increased in tension fibroblasts and reached adult-like configuration at 17 DAB, coinciding with mature hearing characteristics. The role of tension fibroblasts in development of hearing characteristics is discussed.
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Affiliation(s)
- B Kuhn
- Institut für Zoologie der TUM, Garching, Germany.
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