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Bom Braga GO, Parrilli A, Zboray R, Bulatović M, Wagner F. Quantitative Evaluation of the 3D Anatomy of the Human Osseous Spiral Lamina Using MicroCT. J Assoc Res Otolaryngol 2023; 24:441-452. [PMID: 37407801 PMCID: PMC10504225 DOI: 10.1007/s10162-023-00904-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 06/20/2023] [Indexed: 07/07/2023] Open
Abstract
PURPOSE The osseous spiral lamina (OSL) is an inner cochlear bony structure that projects from the modiolus from base to apex, separating the cochlear canal into the scala vestibuli and scala tympani. The porosity of the OSL has recently attracted the attention of scientists due to its potential impact on the overall sound transduction. The bony pillars between the vestibular and tympanic plates of the OSL are not always visible in conventional histopathological studies, so imaging of such structures is usually lacking or incomplete. With this pilot study, we aimed, for the first time, to anatomically demonstrate the OSL in great detail and in 3D. METHODS We measured width, thickness, and porosity of the human OSL by microCT using increasing nominal resolutions up to 2.5-µm voxel size. Additionally, 3D models of the individual plates at the basal and middle turns and the apex were created from the CT datasets. RESULTS We found a constant presence of porosity in both tympanic plate and vestibular plate from basal turn to the apex. The tympanic plate appears to be more porous than vestibular plate in the basal and middle turns, while it is less porous in the apex. Furthermore, the 3D reconstruction allowed the bony pillars that lie between the OSL plates to be observed in great detail. CONCLUSION By enhancing our comprehension of the OSL, we can advance our comprehension of hearing mechanisms and enhance the accuracy and effectiveness of cochlear models.
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Affiliation(s)
- Gabriela O Bom Braga
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Annapaola Parrilli
- Center for X-Ray Analytics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland.
| | - Robert Zboray
- Center for X-Ray Analytics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Milica Bulatović
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Franca Wagner
- Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Eggink MC, Frijns JHM, Sagers JE, O'Malley JT, Liberman MC, Stankovic KM. Human vestibular schwannoma reduces density of auditory nerve fibers in the osseous spiral lamina. Hear Res 2022; 418:108458. [PMID: 35334332 DOI: 10.1016/j.heares.2022.108458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 09/22/2021] [Accepted: 02/05/2022] [Indexed: 12/24/2022]
Abstract
Hearing loss in patients with vestibular schwannoma (VS) is commonly attributed to mechanical compression of the auditory nerve, though recent studies suggest that this retrocochlear pathology may be augmented by cochlear damage. Although VS-associated loss of inner hair cells, outer hair cells, and spiral ganglion cells has been reported, it is unclear to what extent auditory-nerve peripheral axons are damaged in VS patients. Understanding the degree of damage VSs cause to auditory nerve fibers (ANFs) is important for accurately modeling clinical outcomes of cochlear implantation, which is a therapeutic option to rehabilitate hearing in VS-affected ears. A retrospective analysis of human temporal-bone histopathology was performed on archival specimens from the Massachusetts Eye and Ear collection. Seven patients met our inclusion criteria based on the presence of sporadic, unilateral, untreated VS. Tangential sections of five cochlear regions were stained with hematoxylin and eosin, and adjacent sections were stained to visualize myelinated ANFs and efferent fibers. Following confocal microscopy, peripheral axons of ANFs within the osseous spiral lamina were quantified manually, where feasible, and with a "pixel counting" method, applicable to all sections. ANF density was substantially reduced on the VS side compared to the unaffected contralateral side. In the upper basal turn, a significant difference between the VS side and unaffected contralateral side was found using both counting methods, corresponding to the region tuned to 2000 Hz. Even spiral ganglion cells (SGCs) contralateral to VS were affected by the tumor as the majority of contralateral SGC counts were below average for age. This observation provides histological insight into the clinical observation that unilateral vestibular schwannomas pose a long-term risk of progression of hearing loss in the contralateral ear as well. Our pixel counting method for ANF quantification in the osseous spiral lamina is applicable to other pathologies involving sensorineural hearing loss. Future research is needed to classify ANFs into morphological categories, accurately predict their electrical properties, and use this knowledge to inform optimal cochlear implant programming strategies.
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Affiliation(s)
- Maura C Eggink
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA; Department of Otorhinolaryngology, Leiden University Medical Center, Leiden, the Netherlands; Department of Otorhinolaryngology, Amsterdam UMC, location Academic Medical Center, University of Amsterdam, the Netherlands
| | - Johan H M Frijns
- Department of Otorhinolaryngology, Leiden University Medical Center, Leiden, the Netherlands; The Leiden Institute for Brain and Cognition, Leiden, the Netherlands
| | - Jessica E Sagers
- Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA
| | - Jennifer T O'Malley
- Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA
| | - M Charles Liberman
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA
| | - Konstantina M Stankovic
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA; Department of Otolaryngology, Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA.
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Moon SK, Woo JI, Lee HY, Park R, Shimada J, Pan H, Gellibolian R, Lim DJ. Toll-like receptor 2-dependent NF-kappaB activation is involved in nontypeable Haemophilus influenzae-induced monocyte chemotactic protein 1 up-regulation in the spiral ligament fibrocytes of the inner ear. Infect Immun 2007; 75:3361-72. [PMID: 17452470 PMCID: PMC1932924 DOI: 10.1128/iai.01886-06] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Inner ear dysfunction secondary to chronic otitis media (OM), including high-frequency sensorineural hearing loss or vertigo, is not uncommon. Although chronic middle ear inflammation is believed to cause inner ear dysfunction by entry of OM pathogen components or cytokines from the middle ear into the inner ear, the underlying mechanisms are not well understood. Previously, we demonstrated that the spiral ligament fibrocyte (SLF) cell line up-regulates monocyte chemotactic protein 1 (MCP-1) expression after treatment with nontypeable Haemophilus influenzae (NTHI), one of the most common OM pathogens. We hypothesized that the SLF-derived MCP-1 plays a role in inner ear inflammation secondary to OM that is responsible for hearing loss and dizziness. The purpose of this study was to investigate the signaling pathway involved in NTHI-induced MCP-1 up-regulation in SLFs. Here we show for the first time that NTHI induces MCP-1 up-regulation in the SLFs via Toll-like receptor 2 (TLR2)-dependent activation of NF-kappaB. TLR2(-/-)- and MyD88(-/-)-derived SLFs revealed involvement of TLR2 and MyD88 in NTHI-induced MCP-1 up-regulation. Studies using chemical inhibitors and dominant-negative constructs demonstrated that it is mediated by the IkappaKbeta-dependent IkappaBalpha phosphorylation and NTHI-induced NF-kappaB nuclear translocation. Furthermore, we demonstrated that the binding of NF-kappaB to the enhancer region of MCP-1 is involved in this up-regulation. In addition, we have identified a potential NF-kappaB motif that is responsive and specific to certain NTHI molecules or ligands. Further studies are necessary to reveal specific ligands of NTHI that activate host receptors. These results may provide us with new therapeutic strategies for prevention of inner ear dysfunction secondary to chronic middle ear inflammation.
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Affiliation(s)
- Sung K Moon
- The Gonda Department of Cell and Molecular Biology, House Ear Institute, 2100 West 3rd Street, Los Angeles, CA 90057, USA
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Matsunami T, Suzuki T, Hisa Y, Takata K, Takamatsu T, Oyamada M. Gap junctions mediate glucose transport between GLUT1-positive and -negative cells in the spiral limbus of the rat cochlea. ACTA ACUST UNITED AC 2006; 13:93-102. [PMID: 16613783 DOI: 10.1080/15419060600631805] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [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: 10/24/2022]
Abstract
To elucidate the role of the spiral limbus in glucose transport in the cochlea, we analyzed the expression and localization of GLUT1, connexin26, connexin30, and occludin in the spiral limbus of the rat cochlea. GLUT1 and occludin were detected in blood vessels. GLUT1, connexin26, connexin30, and occludin were also expressed in fibrocytes just basal to the supralimbal lining cells. Connexin26 and connexin30 were present among not only these GLUT1-positive fibrocytes but also GLUT1-negative fibrocytes. In vivo glucose imaging using 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-6-deoxyglucose (6-NBDG, MW 342) together with Evans Blue Albumin (EBA, MW 68,000) showed that 6-NBDG was rapidly distributed throughout the spiral limbus, whereas EBA was localized only in the vessels. Moreover, the gap junctional uncoupler heptanol inhibited the distribution of 6-NBDG. These findings suggest that gap junctions play an important role in glucose transport in the spiral limbus, i.e., that gap junctions mediate glucose transport from GLUT1-positive fibrocytes to GLUT1-negative fibrocytes in the spiral limbus.
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Affiliation(s)
- Tatsuya Matsunami
- Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Abstract
It is generally accepted that bone conduction (BC) stimuli yield a traveling wave on the basilar membrane (BM) and hence stimulate the cochlea by the same mechanisms as normal air conduction (AC). The basis for this is the ability to cancel or mask a BC tone with an AC tone and the ability to generate two tone distortion products with a BC tone and an AC tone. The hypothesis is proposed that BC stimulates the BM not only through the hydrodynamics of the scala vestibuli and scala tympani, but also through osseous spiral lamina (OSL) vibrations. To test this hypothesis the BM and OSL response with AC as well as BC stimulation was measured with a laser Doppler vibrometer. Human temporal bones mounted on a shaker were used to record the velocities of the bone per se, the BM and the OSL. The measurements were then converted to relative BM and OSL velocities. The results from the basal turn of the cochlea show similar behavior with AC and BC stimulation. The motion of the OSL at the edge where it connects to the BM is in phase and is typically 6 dB lower than the BM motion. With BC stimulation, there is less phase accumulation in the OSL after the cochlea is drained; the OSL moves due to inertial forces and resonates at approximately 7 kHz. Inertial vibration of the OSL may partially contribute to the total response of BC sound, especially at the high frequencies, although current models of the cochlea assume a rigid OSL. The measurements reported here can be used to include a flexible OSL in cochlear models.
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Affiliation(s)
- Stefan Stenfelt
- Division of Otolaryngology - Head and Neck Surgery, Stanford University Medical Center, Stanford, CA, USA.
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DEL-BO M, CONTI A. [Distribution of acetylcholinesterase in the spiral lamina of the guinea-pig cochlea. (Investigations made with the adult animal, the fetus at term and the newborn)]. Arch Ital Otol Rinol Laringol 1961; 72:44-55. [PMID: 13721398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
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DEL BO M, LIVAN M. [Nerve plexuses of the spiral lamina of the cochlea of the human ear]. Arch Ital Otol Rinol Laringol 1951; 62:251-61. [PMID: 14858024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
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LIVAN M, DEL BO M. [On the existence of marginal and paramarginal nerve plexi at the level of the spiral lamina and the spiral internal sulcus in man]. Acta Anat (Basel) 1951; 13:16-29. [PMID: 14868270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
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