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Okada M, Ogawa H, Takagi T, Nishihara E, Yoshida T, Hyodo J, Shinomori Y, Honda N, Fujiwara T, Teraoka M, Yamada H, Hirano SI, Hato N. A double-blinded, randomized controlled clinical trial of hydrogen inhalation therapy for idiopathic sudden sensorineural hearing loss. Front Neurosci 2022; 16:1024634. [PMID: 36507329 PMCID: PMC9731512 DOI: 10.3389/fnins.2022.1024634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 11/08/2022] [Indexed: 11/25/2022] Open
Abstract
Background Hydrogen (H2) has been reported to be effective in reducing hearing loss due to several causes in animal studies. However, no study has examined the effectiveness of H2 in treating hearing loss in humans. Thus, we investigated whether H2 is effective for the treatment of idiopathic sudden sensorineural hearing loss (ISSNHL). Materials and methods We conducted a double-blind randomized controlled trial at six hospitals between June 2019 and March 2022. The study protocol and trial registration have been published in the Japan Registry of Clinical Trials (jRCT, No. jRCTs06119004). We randomly assigned patients with ISSNHL to receive either H2 (H2 group) or air as a placebo (control group) through inhalation combined with the administration of systemic glucocorticoids and prostaglandin E1. The primary outcome was the hearing threshold and changes in hearing threshold 3 months after therapy. In contrast, the secondary outcomes included the proportion of patients with a good prognosis (complete recovery or marked improvement). Results Sixty-five patients with ISSNHL (31 and 34 in the H2 and control groups, respectively) were included in this study. The hearing threshold 3 months after treatment was not significantly different between the groups; 39.0 decibels (dB) (95% confidence interval [CI]: 28.7-49.3) and 49.5 dB (95% CI: 40.3-58.7) in the H2 and control groups, respectively. In contrast, the changes in hearing threshold 3 months after treatment was 32.7 dB (95% CI: 24.2-41.3) and 24.2 dB (95% CI: 18.1-30.3) in the H2 and control groups, respectively. Consequently, the changes in hearing threshold were significantly better in the H2 group than in the control group (P = 0.048). However, no adverse effects due to the inhalation of H2 gas have been reported. Conclusion This is the first study to investigate the efficacy of H2 for the treatment of ISSNHL in humans. The results suggest that H2 therapy may be effective for ISSNHL treatment. Clinical trial registration [https://jrct.niph.go.jp/re/reports/detail/10442], identifier [jRCTs06119004].
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Affiliation(s)
- Masahiro Okada
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Toon, Japan,*Correspondence: Masahiro Okada,
| | - Hideo Ogawa
- Department of Otolaryngology, Head and Neck Surgery, Ehime Prefectural Central Hospital, Matsuyama, Japan
| | - Taro Takagi
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Toon, Japan,Department of Otolaryngology, Ehime Prefectural Niihama Hospital, Niihama, Japan
| | - Eriko Nishihara
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Toon, Japan,Department of Otolaryngology, Ehime Prefectural Niihama Hospital, Niihama, Japan
| | - Tadashi Yoshida
- Department of Otolaryngology, Head and Neck Surgery, Uwajima City Hospital, Uwajima, Japan
| | - Jun Hyodo
- Department of Otolaryngology, Takanoko Hospital, Matsuyama, Japan
| | - Yusuke Shinomori
- Department of Otolaryngology, Matsuyama Red Cross Hospital, Matsuyama, Japan
| | - Nobumitsu Honda
- Department of Otolaryngology, Head and Neck Surgery, Ehime Prefectural Central Hospital, Matsuyama, Japan
| | - Takashi Fujiwara
- Department of Public Health Research, Kurashiki Clinical Research Institute, Kurashiki, Japan
| | - Masato Teraoka
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Toon, Japan
| | - Hiroyuki Yamada
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Toon, Japan
| | - Shin-ichi Hirano
- Department of Research and Development, MiZ Company Limited, Kamakura, Japan
| | - Naohito Hato
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Toon, Japan
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Okada M, Parthasarathy A, Welling DB, Liberman MC, Maison SF. Idiopathic Sudden Sensorineural Hearing Loss: Speech Intelligibility Deficits Following Threshold Recovery. Ear Hear 2021; 42:782-792. [PMID: 33259444 PMCID: PMC8164648 DOI: 10.1097/aud.0000000000000987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This retrospective study tests the hypothesis that patients who have recovered from idiopathic sudden sensorineural hearing loss (SSNHL) show deficits in word recognition tasks that cannot be entirely explained by a loss in audibility. DESIGN We reviewed the audiologic profile of 166 patients presenting with a unilateral SSNHL. Hearing loss severity, degree of threshold recovery, residual hearing loss, and word recognition performance were considered as outcome variables. Age, route of treatment, delay between SSNHL onset and treatment, and audiogram configuration were considered as predictor variables. RESULTS Severity, residual hearing loss, and recovery were highly variable across patients. While age and onset-treatment delay could not account for the severity, residual hearing loss and recovery in thresholds, configuration of the SSNHL and overall inner ear status as measured by thresholds on the contralateral ear were predictive of threshold recovery. Speech recognition performance was significantly poorer than predicted by the speech intelligibility curve derived from the patient's audiogram. CONCLUSIONS SSNHL is associated with (1) changes in thresholds that are consistent with ischemia and (2) speech intelligibility deficits that cannot be entirely explained by a change in hearing sensitivity.
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Affiliation(s)
- Masahiro Okada
- Department of Otolaryngology – Head & Neck Surgery, Ehime University Graduate School of Medicine, Tōon, Ehime, Japan
| | - Aravindakshan Parthasarathy
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear, Boston MA
- Department of Otolaryngology – Head & Neck Surgery, Harvard Medical School, Boston MA
| | - D. Bradley Welling
- Department of Otolaryngology – Head & Neck Surgery, Harvard Medical School, Boston MA
- Harvard Program in Speech and Hearing Bioscience and Technology, Boston MA
| | - M. Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear, Boston MA
- Department of Otolaryngology – Head & Neck Surgery, Harvard Medical School, Boston MA
- Harvard Program in Speech and Hearing Bioscience and Technology, Boston MA
| | - Stéphane F. Maison
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear, Boston MA
- Department of Otolaryngology – Head & Neck Surgery, Harvard Medical School, Boston MA
- Harvard Program in Speech and Hearing Bioscience and Technology, Boston MA
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Woo H, Kim MK, Park S, Han SH, Shin HC, Kim BG, Oh SH, Suh MW, Lee JH, Park MK. Effect of Phlorofucofuroeckol A and Dieckol Extracted from Ecklonia cava on Noise-induced Hearing Loss in a Mouse Model. Mar Drugs 2021; 19:443. [PMID: 34436282 PMCID: PMC8400186 DOI: 10.3390/md19080443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/23/2021] [Accepted: 07/28/2021] [Indexed: 12/20/2022] Open
Abstract
One of the well-known causes of hearing loss is noise. Approximately 31.1% of Americans between the ages of 20 and 69 years (61.1 million people) have high-frequency hearing loss associated with noise exposure. In addition, recurrent noise exposure can accelerate age-related hearing loss. Phlorofucofuroeckol A (PFF-A) and dieckol, polyphenols extracted from the brown alga Ecklonia cava, are potent antioxidant agents. In this study, we investigated the effect of PFF-A and dieckol on the consequences of noise exposure in mice. In 1,1-diphenyl-2-picrylhydrazyl assay, dieckol and PFF-A both showed significant radical-scavenging activity. The mice were exposed to 115 dB SPL of noise one single time for 2 h. Auditory brainstem response(ABR) threshold shifts 4 h after 4 kHz noise exposure in mice that received dieckol were significantly lower than those in the saline with noise group. The high-PFF-A group showed a lower threshold shift at click and 16 kHz 1 day after noise exposure than the control group. The high-PFF-A group also showed higher hair cell survival than in the control at 3 days after exposure in the apical turn. These results suggest that noise-induced hair cell damage in cochlear and the ABR threshold shift can be alleviated by dieckol and PFF-A in the mouse. Derivatives of these compounds may be applied to individuals who are inevitably exposed to noise, contributing to the prevention of noise-induced hearing loss with a low probability of adverse effects.
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Affiliation(s)
- Hyunjun Woo
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
| | - Min-Kyung Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
| | - Sohyeon Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
- Interdisciplinary Program in Neuroscience, College of Natural Sciences, Seoul National University, Seoul 08826, Korea
| | - Seung-Hee Han
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
| | - Hyeon-Cheol Shin
- CEWIT Center for Systems Biology, State University of New York, Incheon 21985, Korea;
| | - Byeong-gon Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
- Sensory Organ Research Institute, Medical Research Center, Seoul National University, Seoul 03080, Korea
| | - Seung-Ha Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
- Sensory Organ Research Institute, Medical Research Center, Seoul National University, Seoul 03080, Korea
| | - Myung-Whan Suh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
| | - Jun-Ho Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
- Sensory Organ Research Institute, Medical Research Center, Seoul National University, Seoul 03080, Korea
| | - Moo-Kyun Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 03080, Korea; (H.W.); (M.-K.K.); (S.P.); (S.-H.H.); (B.-g.K.); (S.-H.O.); (M.-W.S.); (J.-H.L.)
- Sensory Organ Research Institute, Medical Research Center, Seoul National University, Seoul 03080, Korea
- Wide River Institute of Immunology, College of Medicine, Seoul National University, Hongcheon 25159, Korea
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Sekiya T, Holley MC. Cell Transplantation to Restore Lost Auditory Nerve Function is a Realistic Clinical Opportunity. Cell Transplant 2021; 30:9636897211035076. [PMID: 34498511 PMCID: PMC8438274 DOI: 10.1177/09636897211035076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hearing is one of our most important means of communication. Disabling hearing loss (DHL) is a long-standing, unmet problem in medicine, and in many elderly people, it leads to social isolation, depression, and even dementia. Traditionally, major efforts to cure DHL have focused on hair cells (HCs). However, the auditory nerve is also important because it transmits electrical signals generated by HCs to the brainstem. Its function is critical for the success of cochlear implants as well as for future therapies for HC regeneration. Over the past two decades, cell transplantation has emerged as a promising therapeutic option for restoring lost auditory nerve function, and two independent studies on animal models show that cell transplantation can lead to functional recovery. In this article, we consider the approaches most likely to achieve success in the clinic. We conclude that the structure and biochemical integrity of the auditory nerve is critical and that it is important to preserve the remaining neural scaffold, and in particular the glial scar, for the functional integration of donor cells. To exploit the natural, autologous cell scaffold and to minimize the deleterious effects of surgery, donor cells can be placed relatively easily on the surface of the nerve endoscopically. In this context, the selection of donor cells is a critical issue. Nevertheless, there is now a very realistic possibility for clinical application of cell transplantation for several different types of hearing loss.
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Affiliation(s)
- Tetsuji Sekiya
- Department of Otolaryngology, Head and Neck Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Neurological Surgery, Hikone Chuo Hospital, Hikone, Japan
- Tetsuji Sekiya, Department of Otolaryngology, Head and Neck Surgery, Kyoto University Graduate School of Medicine, 606-8507 Kyoto, Japan,.
| | - Matthew C. Holley
- Department of Biomedical Science, University of Sheffield, Firth Court, Sheffield, England
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Ji L, Lee HJ, Wan G, Wang GP, Zhang L, Sajjakulnukit P, Schacht J, Lyssiotis CA, Corfas G. Auditory metabolomics, an approach to identify acute molecular effects of noise trauma. Sci Rep 2019; 9:9273. [PMID: 31239523 PMCID: PMC6592947 DOI: 10.1038/s41598-019-45385-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/29/2019] [Indexed: 11/26/2022] Open
Abstract
Animal-based studies have provided important insights into the structural and functional consequences of noise exposure on the cochlea. Yet, less is known about the molecular mechanisms by which noise induces cochlear damage, particularly at relatively low exposure levels. While there is ample evidence that noise exposure leads to changes in inner ear metabolism, the specific effects of noise exposure on the cochlear metabolome are poorly understood. In this study we applied liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS)-based metabolomics to analyze the effects of noise on the mouse inner ear. Mice were exposed to noise that induces temporary threshold shifts, synaptopathy and permanent hidden hearing loss. Inner ears were harvested immediately after exposure and analyzed by targeted metabolomics for the relative abundance of 220 metabolites across the major metabolic pathways in central carbon metabolism. We identified 40 metabolites differentially affected by noise. Our approach detected novel noise-modulated metabolites and pathways, as well as some already linked to noise exposure or cochlear function such as neurotransmission and oxidative stress. Furthermore, it showed that metabolic effects of noise on the inner ear depend on the intensity and duration of exposure. Collectively, our results illustrate that metabolomics provides a powerful approach for the characterization of inner ear metabolites affected by auditory trauma. This type of information could lead to the identification of drug targets and novel therapies for noise-induced hearing loss.
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Affiliation(s)
- Lingchao Ji
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Ho-Joon Lee
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Guoqiang Wan
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Guo-Peng Wang
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Li Zhang
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Peter Sajjakulnukit
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Jochen Schacht
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Costas A Lyssiotis
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 48109, Ann Arbor, USA.
| | - Gabriel Corfas
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA.
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6
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Kong TH, Yu S, Jung B, Choi JS, Seo YJ. Monitoring blood-flow in the mouse cochlea using an endoscopic laser speckle contrast imaging system. PLoS One 2018; 13:e0191978. [PMID: 29489849 PMCID: PMC5830291 DOI: 10.1371/journal.pone.0191978] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 01/15/2018] [Indexed: 12/18/2022] Open
Abstract
Laser speckle contrast imaging (LSCI) enables continuous high-resolution assessment of microcirculation in real-time. We applied an endoscope to LSCI to measure cochlear blood-flow in an ischemia–reperfusion mouse model. We also explored whether using xenon light in combination with LSCI facilitates visualization of anatomical position. Based on a previous preliminary study, the appropriate wavelength for penetrating the thin bony cochlea was 830 nm. A 2.7-mm-diameter endoscope was used, as appropriate for the size of the mouse cochlea. Our endoscopic LSCI system was used to illuminate the right cochlea after dissection of the mouse. We observed changes in the speckle signals when we applied the endoscopic LSCI system to the ischemia-reperfusion mouse model. The anatomical structure of the mouse cochlea and surrounding structures were clearly visible using the xenon light. The speckle signal of the cochlea was scattered, with an intensity that varied between that of the stapes (with the lowest signal), the negative control, and the stapedial artery (with the highest signal), the positive control. In the cochlear ischemia–reperfusion mouse model, the speckle signal of the cochlea decreased during the ischemic phase, and increased during the reperfusion phase, clearly reflecting cochlear blood-flow. The endoscopic LSCI system generates high-resolution images in real-time, allowing visualization of blood-flow and its changes in the mouse cochlea. Anatomical structures were clearly matched using LSCI along with visible light.
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Affiliation(s)
- Tae Hoon Kong
- Department of Otorhinolaryngology-Head and Neck Surgery, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | - Sunkon Yu
- Department of Biomedical Engineering, Yonsei University College of Health Science, Wonju, South Korea
| | - Byungjo Jung
- Department of Biomedical Engineering, Yonsei University College of Health Science, Wonju, South Korea
| | - Jin Sil Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | - Young Joon Seo
- Department of Otorhinolaryngology-Head and Neck Surgery, Yonsei University Wonju College of Medicine, Wonju, South Korea
- * E-mail:
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7
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Ogawa H, Okada M, Shudou M, Gyo K, Hato N. Prevention of ischemia-induced hearing loss by intravenous administration of hydrogen-rich saline in gerbil. Neurosci Lett 2017; 665:195-199. [PMID: 29223865 DOI: 10.1016/j.neulet.2017.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 11/28/2017] [Accepted: 12/05/2017] [Indexed: 02/08/2023]
Abstract
OBJECTIVE Hydrogen-rich water, which is a potent antioxidant agent, was investigated for its protective effects against ischemic damage of the cochlea in gerbils. METHODS The animals were subjected to transient cochlear ischemia by occluding the bilateral vertebral arteries for l5min. Five milliliters of hydrogen-rich saline was then intravenously administered immediately after the insult. Saline without hydrogen was used as a control. Effects of hydrogen were evaluated using the auditory brainstem response (ABR) and histological studies of the inner ear. RESULTS In non-ischemia animals, ABR thresholds and histological findings of the cochlea did not change by administration of saline or hydrogen-rich saline. In contrast, transient cochlear ischemia caused a 24.2±3.8dB increase in the ABR threshold at 8kHz, and a decrease of 14.1%±1.8% in the number of inner hair cells (IHCs) at the basal turn on day 7. Ischemic damage was more severe at 16 and 32kHz. When the animals were treated with hydrogen-rich saline, cochlear damage was significantly reduced: the increase in ABR threshold was 11.7±2.6dB at 8kHz and the IHC loss was 7.5%±2.1% at the basal turn on day 7. The effects of hydrogen-rich saline were more prominent at higher frequencies. CONCLUSIONS Intravenous administration of hydrogen-rich saline was effective in preventing acute hearing loss due to transient cochlear ischemia.
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Affiliation(s)
- Hideo Ogawa
- Ehime University Graduate School of Medicine, Otolaryngology Head and Neck Surgery, Shitsukawa, Toon, Ehime, 791-0295, Japan.
| | - Masahiro Okada
- Ehime University Graduate School of Medicine, Otolaryngology Head and Neck Surgery, Shitsukawa, Toon, Ehime, 791-0295, Japan.
| | - Masachika Shudou
- Ehime University Graduate School of Medicine, Division of Analytical Bio-Medicine, Advanced Research Support Center (ADRES), Shitsukawa, Toon, Ehime, 791-0295, Japan.
| | - Kiyofumi Gyo
- Takanoko Hospital, Otolaryngology, Takanoko 525-1, Matsuyama, Ehime, 790-0925, Japan.
| | - Naohito Hato
- Ehime University Graduate School of Medicine, Otolaryngology Head and Neck Surgery, Shitsukawa, Toon, Ehime, 791-0295, Japan.
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Onal M, Elsurer C, Selimoglu N, Yilmaz M, Erdogan E, Bengi Celik J, Kal O, Onal O. Ozone Prevents Cochlear Damage From Ischemia-Reperfusion Injury in Guinea Pigs. Artif Organs 2017; 41:744-752. [DOI: 10.1111/aor.12863] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 07/21/2016] [Accepted: 08/17/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Merih Onal
- Department of Otorhinolaryngology; Konya Educational and Training Hospital
| | - Cagdas Elsurer
- Department of Otolaryngology; Selcuk University Medical Faculty
| | - Nebil Selimoglu
- Department of Plastic Surgery; Konya Educational and Training Hospital
| | | | | | - Jale Bengi Celik
- Department of Anesthesiology and Reanimation; Selcuk University Medical Faculty
| | - Oznur Kal
- Department of Nephrology; Baskent University Medical Faculty; Konya Turkey
| | - Ozkan Onal
- Department of Anesthesiology and Reanimation; Selcuk University Medical Faculty
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Excessive activation of ionotropic glutamate receptors induces apoptotic hair-cell death independent of afferent and efferent innervation. Sci Rep 2017; 7:41102. [PMID: 28112265 PMCID: PMC5255535 DOI: 10.1038/srep41102] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 12/15/2016] [Indexed: 02/07/2023] Open
Abstract
Accumulation of excess glutamate plays a central role in eliciting the pathological events that follow intensely loud noise exposures and ischemia-reperfusion injury. Glutamate excitotoxicity has been characterized in cochlear nerve terminals, but much less is known about whether excess glutamate signaling also contributes to pathological changes in sensory hair cells. I therefore examined whether glutamate excitotoxicity damages hair cells in zebrafish larvae exposed to drugs that mimic excitotoxic trauma. Exposure to ionotropic glutamate receptor (iGluR) agonists, kainic acid (KA) or N-methyl-D-aspartate (NMDA), contributed to significant, progressive hair cell loss in zebrafish lateral-line organs. To examine whether hair-cell loss was a secondary effect of excitotoxic damage to innervating neurons, I exposed neurog1a morphants-fish whose hair-cell organs are devoid of afferent and efferent innervation-to KA or NMDA. Significant, dose-dependent hair-cell loss occurred in neurog1a morphants exposed to either agonist, and the loss was comparable to wild-type siblings. A survey of iGluR gene expression revealed AMPA-, Kainate-, and NMDA-type subunits are expressed in zebrafish hair cells. Finally, hair cells exposed to KA or NMDA appear to undergo apoptotic cell death. Cumulatively, these data reveal that excess glutamate signaling through iGluRs induces hair-cell death independent of damage to postsynaptic terminals.
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10
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Chang MY, Han SY, Shin HC, Byun JY, Rah YC, Park MK. Protective effect of a purified polyphenolic extract from Ecklonia cava against noise-induced hearing loss: Prevention of temporary threshold shift. Int J Pediatr Otorhinolaryngol 2016; 87:178-84. [PMID: 27368468 DOI: 10.1016/j.ijporl.2016.06.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/06/2016] [Accepted: 06/08/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Noise is one of the most common causes of hearing loss. Approximately 16% of American teenagers (12-19 years) have hearing loss caused by loud noise. The implication of noise-induced hearing loss (NIHL) in teenagers has received increasing attention. Although temporary threshold shift (TTS), a type of NIHL, is a transient hearing loss, it can accelerate age-related hearing loss. Reactive oxygen species are a primary cause of TTS. As the polyphenols from Ecklonia cava are known to have potent antioxidant effects, we investigated the protective effects of a purified polyphenolic extract of Ecklonia cava (PPEE) against TTS in mice. METHODS The radical-scavenging activity of PPEE was evaluated using the 1,1-diphenyl-2-picrylhydrazyl assay. The PPEE + Noise and Saline + Noise groups were administered intraperitoneal PPEE (100 mg/kg) and saline, respectively, for 5 days before exposure to noise at 100 dB SPL for 60 min. Hearing ability was assessed following noise exposure using auditory brainstem responses and distortion product otoacoustic emissions. RESULTS PPEE exhibited significant radical scavenging activity. The ABR threshold shifts 1 day after exposure to noise at 16 kHz and 1, 7, and 14 days after exposure to noise at 32 kHz, were significantly less in the PPEE + Noise than in the Saline + Noise group. One day after noise exposure, mice in the PPEE + Noise group showed a significant degree of protection in relation to their DPOAE level at f2, 17, and 28 kHz. CONCLUSIONS These findings suggest that PPEE may be a potential preventive agent against TTS. In addition, as a food ingredient approved by the United States Food and Drug Administration, PPEE may be administered to those who are exposed to noise inevitably with little likelihood of adverse effects, thereby contributing to the prevention of TTS.
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Affiliation(s)
- Mun Young Chang
- Department of Otorhinolaryngology-Head and Neck Surgery, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Song Yee Han
- Department of Interdisciplinary Program in Biomedical Science, Major Graduate School of Soonchunhyang University, Asan-si, Republic of Korea
| | - Hyeon-Cheol Shin
- CEWIT Center for Systems Biology, State University of New York, Incheon, Republic of Korea
| | - Jang Yul Byun
- Department of Otolaryngology-Head and Neck Surgery, Soon Chun Hyang University College of Medicine, Seoul, Republic of Korea
| | - Yoon Chan Rah
- Department of Otolaryngology-Head and Neck Surgery, Korea University Medical Center Ansan Hospital, Ansan-si, Republic of Korea
| | - Moo Kyun Park
- Department of Otolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.
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12
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Ezerarslan H, Sanhal EO, Kurukahvecioğlu S, Ataç GK, Kocatürk S. Presence of vascular loops entering internal acoustic channel may increase risk of Sudden sensorineural hearing loss and reduce recovery of these patients. Laryngoscope 2016; 127:210-215. [DOI: 10.1002/lary.26054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Hande Ezerarslan
- Department of Otorhinolaryngology; Ufuk University Medical School; Ankara Turkey
| | - Ebru Ozan Sanhal
- Department of Radiology; Ufuk University Medical School; Ankara Turkey
| | - Selma Kurukahvecioğlu
- Department of Otorhinolaryngology; Ankara Numune Education and Training Hospital; Ankara Turkey
| | - Gökçe Kaan Ataç
- Department of Radiology; Ufuk University Medical School; Ankara Turkey
| | - Sinan Kocatürk
- Department of Otorhinolaryngology; Ufuk University Medical School; Ankara Turkey
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13
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Reijntjes DO, Pyott SJ. The afferent signaling complex: Regulation of type I spiral ganglion neuron responses in the auditory periphery. Hear Res 2016; 336:1-16. [DOI: 10.1016/j.heares.2016.03.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 02/12/2016] [Accepted: 03/07/2016] [Indexed: 12/19/2022]
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14
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Terashita T, Saito S, Nabeka H, Hato N, Wakisaka H, Shimokawa T, Kobayashi N, Gyo K, Matsuda S. Prosaposin-derived peptide alleviates ischaemia-induced hearing loss. Acta Otolaryngol 2013; 133:462-8. [PMID: 23216090 DOI: 10.3109/00016489.2012.750430] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION An 18-mer peptide derived from the neurotrophic region of prosaposin (PS-pep) prevents hearing loss and cochlear damage due to transient cochlear ischaemia by activating an anti-apoptotic pathway. PS-pep is a potent candidate molecule for alleviating ischaemia-induced hearing loss. OBJECTIVE PS-pep was investigated for its protective effects against ischaemia-induced hearing loss and cochlear damage. METHODS Ischaemia was induced in both cochleae in Mongolian gerbils by pulling the ligatures around both vertebral arteries in an anterior direction using 5 g weights for 15 min. PS-pep was synthesized artificially and administered subcutaneously four times after the induction of transient cochlear ischaemia. RESULTS An increase in the auditory brainstem response threshold was alleviated in animals treated with 2.0 mg/kg PS-pep. Histological examinations conducted on day 7 showed that the loss of inner hair cells (IHCs) was more prominent than that of outer hair cells. Higher doses of PS-pep significantly alleviated IHC loss. An increase in the anti-apoptotic factor bcl-2 was also noted in the IHCs treated with PS-pep.
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Affiliation(s)
- Takehiro Terashita
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
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15
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Abstract
OBJECTIVE AM-111, a cell-permeable peptide inhibitor of c-Jun N-terminal kinase, was investigated for its protective effects against ischemic damage of the cochlea in gerbils. METHODS Transient cochlear ischemia was introduced in animals by occluding the bilateral vertebral arteries for l5 minutes. Then, 10 μl of AM-111 at a concentration of l, 10, or 100 μM in hyaluronic acid gel formulation was applied onto the round window 30 minutes after the insult. Gel without active substance was used in a control group. Treatment effects were evaluated by auditory brainstem response (ABR) and histology of the inner ear. RESULTS In controls, transient cochlear ischemia caused a 25.0 ± 5.0 dB increase in the ABR threshold at 8 kHz and a decrease of 13.3 ± 2.3% in inner hair cells at the basal turn on Day 7. Ischemic damage was mild at 2 and 4 kHz. When the animals were treated with AM-111 at 100 μM, cochlear damage was significantly reduced: the increase in ABR threshold was 3.3 ± 2.4 dB at 8 kHz, and the inner hair cell loss was 3.1 ± 0.6% at the basal turn on Day 7. The effects of AM-111 were concentration dependent: 100 μM was more effective than 1 or 10 μM. CONCLUSION Direct application of AM-111 in gel formulation on the round window was effective in preventing acute hearing loss because of transient cochlear ischemia.
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Sasaki A, Matsubara A, Tabuchi K, Hara A, Namba A, Yamamoto Y, Shinkawa H. Immunoelectron microscopic analysis of neurotoxic effect of glutamate in the vestibular end organs during ischemia. Acta Otolaryngol 2012; 132:686-92. [PMID: 22497451 DOI: 10.3109/00016489.2012.656322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION The excessive glutamate released from the type I and type II hair cells and the supporting cells injure the bouton-type endings and the nerve chalices in 30 min ischemia, and neuronal damage of glutamate was slight in 10 min ischemia. OBJECTIVE In the present study, we investigated by means of post-embedding immunoelectron microscopic analysis whether neuronal damage in the vestibular end organs is associated with the change of cellular glutamate concentration during ischemia. METHODS Transient local anoxia (10 min, 30 min) of guinea pig inner ear was induced by pressing the left labyrinthine artery. The right sides were used as controls. The morphological changes of the vestibular end organs and the areal gold particle densities representing glutamate were compared in the ischemia side and the control side. RESULTS The areal gold particle densities of the type I and type II hair cells and the supporting cells in the ischemic side were lower than those of the control side. There were no remarkable morphological changes compared to the control side in 10 min ischemia. In 30 min ischemia, the bouton-type endings were swollen and intercellular spaces between the type I hair cells and the nerve chalices were enlarged.
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Affiliation(s)
- Akira Sasaki
- Department of Otorhinolaryngology, Hirosaki University Graduate School of Medicine, Japan
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17
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Okada M, Kawaguchi AT, Hakuba N, Takeda S, Hyodo J, Imai K, Hato N, Gyo K. Liposome-Encapsulated Hemoglobin Alleviates Hearing Loss After Transient Cochlear Ischemia and Reperfusion in the Gerbil. Artif Organs 2011; 36:178-84. [PMID: 21955137 DOI: 10.1111/j.1525-1594.2011.01306.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Masahiro Okada
- Ehime University Graduate School of Medicine, Otolaryngology Shitsukawa, Toon, Japan
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18
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Lendvai B, Halmos GB, Polony G, Kapocsi J, Horváth T, Aller M, Sylvester Vizi E, Zelles T. Chemical neuroprotection in the cochlea: The modulation of dopamine release from lateral olivocochlear efferents. Neurochem Int 2011; 59:150-8. [DOI: 10.1016/j.neuint.2011.05.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 05/12/2011] [Accepted: 05/17/2011] [Indexed: 01/16/2023]
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19
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Tabuchi K, Nishimura B, Tanaka S, Hayashi K, Hirose Y, Hara A. Ischemia-reperfusion injury of the cochlea: pharmacological strategies for cochlear protection and implications of glutamate and reactive oxygen species. Curr Neuropharmacol 2011; 8:128-34. [PMID: 21119884 PMCID: PMC2923367 DOI: 10.2174/157015910791233123] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 01/15/2010] [Accepted: 02/04/2010] [Indexed: 11/22/2022] Open
Abstract
A large amount of energy produced by active aerobic metabolism is necessary for the cochlea to maintain its function. This makes the cochlea vulnerable to blockade of cochlear blood flow and interruption of the oxygen supply. Although certain forms of human idiopathic sudden sensorineural hearing loss reportedly arise from ischemic injury, the pathological mechanism of cochlear ischemia-reperfusion injury has not been fully elucidated. Recent animal studies have shed light on the mechanisms of cochlear ischemia-reperfusion injury. It will help in the understanding of the pathology of cochlear ischemia-reperfusion injury to classify this injury into ischemic injury and reperfusion injury. Excitotoxicity, mainly observed during the ischemic period, aggravates the injury of primary auditory neurons. On the other hand, oxidative damage induced by hydroxyl radicals and nitric oxide enhances cochlear reperfusion injury. This article briefly summarizes the generation mechanisms of cochlear ischemia-reperfusion injury and potential therapeutic targets that could be developed for the effective management of this injury type.
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Affiliation(s)
- Keiji Tabuchi
- Department of Otolaryngology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.
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20
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Watanabe F, Hakuba N, Gyo K. Measurement of DPOAE after ischemia/reperfusion injury of the cochlea in gerbils. Neurosci Lett 2009; 467:135-8. [DOI: 10.1016/j.neulet.2009.10.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 10/02/2009] [Accepted: 10/06/2009] [Indexed: 10/20/2022]
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21
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Abstract
Glutamate neurotoxicity in cochlear hair cells was investigated by administering the glutamate agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) into the scala tympani of Mongolian gerbils. AMPA administration caused the formation of large number of vacuoles in the inner hair cells (IHCs) and dendritic terminals. The number of degenerated hair cells was counted using rhodamine-phalloidin and Hoechst 33342 staining. The administration of 50 microM AMPA caused reversible elevation of the auditory brainstem response threshold without loss of IHCs. In contrast, 200 microM AMPA induced a substantial elevation of the auditory brainstem response threshold with the characteristic disappearance of IHCs. As cochlear ischemia involves excessive glutamate release, these results suggest that an elevated glutamate level in the cochlea is responsible for the progressive IHC death related to ischemic injury.
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22
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Takeda S, Hata R, Cao F, Yoshida T, Hakuba N, Hato N, Gyo K. Ischemic tolerance in the cochlea. Neurosci Lett 2009; 462:263-6. [PMID: 19596048 DOI: 10.1016/j.neulet.2009.07.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 07/06/2009] [Accepted: 07/07/2009] [Indexed: 12/22/2022]
Abstract
Ischemic tolerance in the cochlea was investigated in a gerbil model of cochlear ischemia. Transient cochlear ischemia was produced by extracranial occlusion of the bilateral vertebral arteries. The gerbils were divided into two groups; single ischemia group and double ischemia group. In the single ischemia group, animals were subjected to lethal cochlear ischemia for 15 min. In the double ischemia group, animals were subjected to sublethal cochlear ischemia for 2 min at 2 days before lethal ischemia for 15 min. Consequently, sublethal ischemia prevented lethal ischemia-induced hair cell degeneration and ameliorated hearing impairment, suggesting ischemic tolerance in the cochlea.
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Affiliation(s)
- Shoichiro Takeda
- Department of Otolaryngology, Ehime University Graduate School of Medicine, Shitsukawa, Ehime, Japan
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23
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Insulin-like growth factor 1 treatment via hydrogels rescues cochlear hair cells from ischemic injury. Neuroreport 2008; 19:1585-8. [PMID: 18845939 DOI: 10.1097/wnr.0b013e328311ca4b] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This study was designed to investigate the protective effects of recombinant human insulin-like growth factor 1 (rhIGF1), applied locally via a hydrogel, against ischemic damage of the cochleae in gerbils. A hydrogel was immersed in rhIGF1 or saline and was applied on the round window membrane 30 min after the ischemia. Local rhIGF1 treatment significantly reduced the elevation of auditory brain responses thresholds at a frequency of 8 kHz on days 1, 4, and 7 after ischemia. A histological analysis revealed increased survival of inner hair cells in the animals treated with rhIGF1 via the hydrogel 7 days after ischemia. These findings showed that local rhIGF1 application using a hydrogel has the potential to protect the cochleae from ischemic injury.
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Abstract
The effect of postischemic mild hypothermia on the inner ear has not been clarified. In this study, we investigated whether hypothermia after transient ischemia could prevent cochlear damage and its therapeutic time window. Mongolian gerbils were divided into six groups: a sham-operation group, a normothermia group, and four hypothermia groups in which hypothermia was induced 1-7, 1-4, 3-6, and 6-9 h after reperfusion. Animals subjected to postischemic mild hypothermia within 3 h after reperfusion had attenuated hearing loss and inner hair cell loss. The protective effect was greater when hypothermia was induced earlier and had a longer duration. This implies that mild hypothermia after ischemia could have therapeutic effects for inner ear ischemic damage.
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25
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Yoshida T, Hakuba N, Morizane I, Fujita K, Cao F, Zhu P, Uchida N, Kameda K, Sakanaka M, Gyo K, Hata R. Hematopoietic stem cells prevent hair cell death after transient cochlear ischemia through paracrine effects. Neuroscience 2007; 145:923-30. [PMID: 17320298 DOI: 10.1016/j.neuroscience.2006.12.067] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2006] [Revised: 12/21/2006] [Accepted: 12/23/2006] [Indexed: 01/01/2023]
Abstract
Transplantation of hematopoietic stem cells (HSCs) is regarded to be a potential approach for promoting repair of damaged organs. Here, we investigated the influence of hematopoietic stem cells on progressive hair cell degeneration after transient cochlear ischemia in gerbils. Transient cochlear ischemia was produced by extracranial occlusion of the bilateral vertebral arteries just before their entry into the transverse foramen of the cervical vertebra. Intrascalar injection of HSCs prevented ischemia-induced hair cell degeneration and ameliorated hearing impairment. We also showed that the protein level of glial cell line-derived neurotrophic factor (GDNF) in the organ of Corti was upregulated after cochlear ischemia and that treatment with HSCs augmented this ischemia-induced upregulation of GDNF. A tracking study revealed that HSCs injected into the cochlea were retained in the perilymphatic space of the cochlea, although they neither transdifferentiated into cochlear cell types nor fused with the injured hair cells after ischemia, suggesting that HSCs had therapeutic potential possibly through paracrine effects. Thus, we propose HSCs as a potential new therapeutic strategy for hearing loss.
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Affiliation(s)
- T Yoshida
- Department of Otolaryngology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan
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26
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Fujita K, Hakuba N, Hata R, Morizane I, Yoshida T, Shudou M, Sakanaka M, Gyo K. Ginsenoside Rb1 protects against damage to the spiral ganglion cells after cochlear ischemia. Neurosci Lett 2007; 415:113-7. [PMID: 17296266 DOI: 10.1016/j.neulet.2007.01.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 12/22/2006] [Accepted: 01/03/2007] [Indexed: 12/14/2022]
Abstract
The effects of transient cochlear ischemia on spiral ganglion cells (SGCs) were studied in Mongolian gerbils. Ischemic insult was induced by occluding the bilateral vertebral arteries of gerbils for 15min. Seven days after ischemia, the percentage of SGCs decreased to 67.5% from the preischemic baseline in the basal turn. Evaluation with immunohistochemical staining showed TUNEL-positive reactions in the SGCs with fragmented nuclei. In addition, we investigated the protective effects of ginsenoside Rb1 (gRb1) against ischemic injury to SGCs. Seven days after ischemia, the auditory brainstem response threshold shift was significantly reduced and the percentage of SGCs decreased to 90.2% from the preischemic baseline in the basal turn in the gRb1-treated group. These findings suggest that gRb1 prevented hearing loss caused by ischemic injury to SGCs in Mongolian gerbils.
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Affiliation(s)
- Kensuke Fujita
- Department of Otolaryngology, Ehime University School of Medicine, Ehime, Japan
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27
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Moser T, Brandt A, Lysakowski A. Hair cell ribbon synapses. Cell Tissue Res 2006; 326:347-59. [PMID: 16944206 PMCID: PMC4142044 DOI: 10.1007/s00441-006-0276-3] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Accepted: 06/08/2006] [Indexed: 11/24/2022]
Abstract
Hearing and balance rely on the faithful synaptic coding of mechanical input by the auditory and vestibular hair cells of the inner ear. Mechanical deflection of their stereocilia causes the opening of mechanosensitive channels, resulting in hair cell depolarization, which controls the release of glutamate at ribbon-type synapses. Hair cells have a compact shape with strong polarity. Mechanoelectrical transduction and active membrane turnover associated with stereociliar renewal dominate the apical compartment. Transmitter release occurs at several active zones along the basolateral membrane. The astonishing capability of the hair cell ribbon synapse for temporally precise and reliable sensory coding has been the subject of intense investigation over the past few years. This research has been facilitated by the excellent experimental accessibility of the hair cell. For the same reason, the hair cell serves as an important model for studying presynaptic Ca(2+) signaling and stimulus-secretion coupling. In addition to common principles, hair cell synapses differ in their anatomical and functional properties among species, among the auditory and vestibular organs, and among hair cell positions within the organ. Here, we briefly review synaptic morphology and connectivity and then focus on stimulus-secretion coupling at hair cell synapses.
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Affiliation(s)
- Tobias Moser
- Department of Otolaryngology and Center for Molecular Physiology of the Brain, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
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28
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Halmos G, Doleviczényi Z, Répássy G, Kittel A, Vizi ES, Lendvai B, Zelles T. D2 autoreceptor inhibition reveals oxygen-glucose deprivation-induced release of dopamine in guinea-pig cochlea. Neuroscience 2005; 132:801-9. [PMID: 15837140 DOI: 10.1016/j.neuroscience.2005.01.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2005] [Indexed: 11/29/2022]
Abstract
Dopamine (DA), released from the lateral olivocochlear (LOC) efferent terminals, the efferent arm of the short-loop feedback in the cochlea, is considered as a protective factor in the inner ear since it inhibits auditory nerve dendrite firing in ischemia- or noise-induced excitotoxicity leading to sensorineural hearing loss (SNHL). In the present study we investigated the effect of oxygen-glucose deprivation (OGD), an in vitro ischemia model, on guinea-pig cochlear [(3)H]DA release in a microvolume superfusion system. We found that OGD alone failed to induce a detectable elevation of [(3)H]DA level, but in the presence of specific D(2) receptor antagonists, sulpiride and L-741,626, it evoked a significant increase in the extracellular concentration of [(3)H]DA. D(2) negative feedback receptors are involved not exclusively in the regulation of synthesis and vesicular release of DA, but also in the activation of its reuptake. Thus, D(2) receptor antagonism interferes with the powerful reuptake of DA from the extracellular space. To explore the underlying mechanism of this DA-releasing effect we applied nomifensine and found that the effect of OGD on cochlear DA release in the presence of D(2) antagonists could be inhibited by this selective DA uptake inhibitor. This finding indicates that the OGD-evoked DA release was mainly mediated through the reverse operation of the DA transporter. The two structurally different D(2) antagonists also augmented the electrical field stimulation-evoked release of DA proving the presence of D(2) autoreceptors on dopaminergic LOC terminals. Our results confirm the presence and role of D(2) DA autoreceptors in the regulation of DA release from LOC efferents, and suggest a protective local mechanism during ischemia which involves the direct transporter-mediated release of DA. Increasing the release of the protective transmitter DA locally in the inner ear may form the basis of future new therapeutic strategies in patients suffering from SNHL.
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Affiliation(s)
- G Halmos
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, H-1083 Budapest, Hungary
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29
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Morizane I, Hakuba N, Shimizu Y, Shinomori Y, Fujita K, Yoshida T, Shudou M, Gyo K. Transient cochlear ischemia and its effects on the stria vascularis. Neuroreport 2005; 16:799-802. [PMID: 15891573 DOI: 10.1097/00001756-200505310-00004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effects of transient cochlear ischemia on the stria vascularis were studied. Fifteen minutes of ischemia decreased the endocochlear potential by up to 17.5 mV on day 1; it returned to normal on day 7. Immunostaining for Na+,K+-ATPase, a marker for the Na+/K+-pump, and for connexin 26, a marker for gap junctions, was inhibited on days 1 and 4, and returned to normal on day 7. Electron microscopy showed expansion of the intercellular space with abundant vacuolar formation in the stria vascularis. These morphological changes disappeared completely by day 7. The results indicate that transient ischemia causes a reversible functional disorder of the stria vascularis with fine structural changes, which may be owing to dysfunction of Na+/K+-pump or gap junctions.
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Affiliation(s)
- Isao Morizane
- Department of Otolaryngology, Ehime University School of Medicine, Ehime, Japan
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30
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Nicolas MT, Lesage F, Reyes R, Barhanin J, Demêmes D. Localization of TREK-1, a two-pore-domain K+ channel in the peripheral vestibular system of mouse and rat. Brain Res 2004; 1017:46-52. [PMID: 15261098 DOI: 10.1016/j.brainres.2004.05.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2004] [Indexed: 10/26/2022]
Abstract
The distribution of two-pore-domain (2P-domain) K(+) channels of the TREK subfamily was studied using immunocytochemistry in the peripheral vestibular system of mouse and rat. Using RT-PCR, the mRNA for TREK-1, but not for TREK-2 or TRAAK, were detected in mouse vestibular endorgans and ganglia. The TREK-1 channel protein was immunodetected in both nerve fibers and nerve cell bodies in the vestibular ganglion, both afferent fibers and nerve calyces innervating type I hair cells in the utricle and cristae. The post-synaptic localization in afferent calyces may suggest a neuroprotective role in glutamatergic excitotoxicity during ischemic conditions. In non-neuronal cells, TREK-1 was immunodetected in the apical membrane of dark cells and transitional cells, both of which are involved in endolymph K(+) secretion and recycling. TREK-1 may subserve some neuroprotective function in afferent nerve fibers as well as play a role in endolymph potassium homeostasis.
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Affiliation(s)
- Marie-Thérèse Nicolas
- Université Montpellier 2, Place Eugène Bataillon, P.O. Box 089, 34095 Montpellier, cedex 05, France.
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Nakashima T, Naganawa S, Sone M, Tominaga M, Hayashi H, Yamamoto H, Liu X, Nuttall AL. Disorders of cochlear blood flow. ACTA ACUST UNITED AC 2004; 43:17-28. [PMID: 14499459 DOI: 10.1016/s0165-0173(03)00189-9] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The cochlea is principally supplied from the inner ear artery (labyrinthine artery), which is usually a branch of the anterior inferior cerebellar artery. Cochlear blood flow is a function of cochlear perfusion pressure, which is calculated as the difference between mean arterial blood pressure and inner ear fluid pressure. Many otologic disorders such as noise-induced hearing loss, endolymphatic hydrops and presbycusis are suspected of being related to alterations in cochlear blood flow. However, the human cochlea is not easily accessible for investigation because this delicate sensory organ is hidden deep in the temporal bone. In patients with sensorineural hearing loss, magnetic resonance imaging, laser-Doppler flowmetry and ultrasonography have been used to investigate the status of cochlear blood flow. There have been many reports of hearing loss that were considered to be caused by blood flow disturbance in the cochlea. However, direct evidence of blood flow disturbance in the cochlea is still lacking in most of the cases.
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Affiliation(s)
- Tsutomu Nakashima
- Department of Otorhinolaryngology, Nagoya University School of Medicine, Nagoya, Japan.
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Hakuba N, Matsubara A, Hyodo J, Taniguchi M, Maetani T, Shimizu Y, Tsujiuchi Y, Shudou M, Gyo K. AMPA/kainate-type glutamate receptor antagonist reduces progressive inner hair cell loss after transient cochlear ischemia. Brain Res 2003; 979:194-202. [PMID: 12850586 DOI: 10.1016/s0006-8993(03)02919-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We investigated the effect of glutamate receptor antagonists on progressive inner hair cell (IHC) loss following transient cochlear ischemia in gerbils. Transient cochlear ischemia was induced by 15-min bilateral vertebral artery occlusion. An alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate-type glutamate receptor antagonist, 6-7-dinitroquinoxaline-2,3-dione (DNQX), or an N-methyl-D-aspartate (NMDA)-type receptor antagonist, MK-801, was administered 10 min before the ischemic insult. Hearing was assessed by sequentially recording compound action potentials (CAPs) before, during, and after the ischemia. The degree of hair cell loss in the organ of Corti was evaluated in specimens stained with rhodamine-phalloidin and Hoechst 33342. On the seventh day after ischemia, the increases in the CAP threshold and the progressive IHC loss were significantly reduced in cochleae treated with DNQX, while MK-801 was ineffective. These results suggest that the AMPA receptor plays a critical role in the development of the progressive IHC loss induced by ischemia/reperfusion injury in the cochlea.
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MESH Headings
- Acoustic Stimulation
- Action Potentials/drug effects
- Animals
- Cochlea/blood supply
- Cochlea/pathology
- Cochlea/ultrastructure
- Cochlear Nerve/drug effects
- Cochlear Nerve/ultrastructure
- Dizocilpine Maleate/pharmacology
- Excitatory Amino Acid Antagonists/pharmacology
- Gerbillinae
- Hair Cells, Auditory, Inner/drug effects
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Inner/ultrastructure
- Hearing/drug effects
- Immunohistochemistry
- Ischemia/drug therapy
- Male
- Microscopy, Electron
- Quinoxalines/pharmacology
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/ultrastructure
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/ultrastructure
- Synapses/drug effects
- Synapses/ultrastructure
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Affiliation(s)
- Nobuhiro Hakuba
- Department of Otolaryngology, Ehime University School of Medicine, Shigenobu-cho, Onsen-gun, 791-0295, Ehime, Japan.
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33
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Hakuba N, Watabe K, Hyodo J, Ohashi T, Eto Y, Taniguchi M, Yang L, Tanaka J, Hata R, Gyo K. Adenovirus-mediated overexpression of a gene prevents hearing loss and progressive inner hair cell loss after transient cochlear ischemia in gerbils. Gene Ther 2003; 10:426-33. [PMID: 12601397 DOI: 10.1038/sj.gt.3301917] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The use of adenoviral vectors has recently provided a novel strategy for direct gene transfer into the cochlea. In this study, we assessed the utility of an adenoviral vector expressing glial-cell-derived neurotrophic factor (GDNF) in ischemia-reperfusion injury of the gerbil cochlea. The vector was injected through the round window 4 days before ischemic insult. The distribution of a reporter transgene was confirmed throughout the cochlea from the basal to the apical turn and Western blot analysis indicated significant upregulation of GDNF protein 11 days following virus inoculation. Hearing ability was assessed by sequentially recording compound action potentials (CAP), and the degree of hair cell loss in the organ of Corti was evaluated in specimens stained with rhodamine-phalloidin and Hoechst 33342. On the seventh day of ischemia, the CAP threshold shift and inner hair cell loss were remarkably suppressed in the Ad-GDNF group compared with the control group. These results suggest that adenovirus-mediated overexpression of GDNF is useful for protection against hair cell damage, which otherwise eventually occurs after transient ischemia of the cochlea.
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Affiliation(s)
- N Hakuba
- Department of Otolaryngology, Ehime University School of Medicine, Shigenobu-cho, Onsen-gun, Ehime, Japan
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34
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Koga K, Hakuba N, Watanabe F, Shudou M, Nakagawa T, Gyo K. Transient cochlear ischemia causes delayed cell death in the organ of Corti: an experimental study in gerbils. J Comp Neurol 2003; 456:105-11. [PMID: 12509868 DOI: 10.1002/cne.10479] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
To elucidate whether ischemia-reperfusion can cause delayed cell death in the cochlea, the effects of transient cochlear ischemia on hearing and on neuronal structures in the cochlea were studied in Mongolian gerbils. Ischemia was induced by bilaterally occluding the vertebral arteries for 5 minutes in gerbils, which lack posterior cerebral communicating arteries. In gerbils, the labyrinthine arteries are fed solely by the vertebral arteries. Occlusion of the vertebral arteries caused a remarkable increase in the threshold of compound action potentials (CAPs), which recovered over the following day. However, 7 days after the onset of reperfusion, the threshold began to increase again. Morphologic changes in the hair cell stereocilia were revealed by electron microscopy. The number of nuclear collapses was counted in cells stained for DNA and F-actin to evaluate the degree of cell death in the organ of Corti. Changes in spiral ganglion cell (SGC) neuron number were detected, whether or not progressive neuronal death occurred in the SGC. These studies showed that sporadic fusion of hair cells and the disappearance of hair cell stereocilia did not begin until 4 days after ischemia. On subsequent days, the loss of hair cells, especially inner hair cells (IHCs), and the degeneration of SGC neurons became apparent. Ten days after ischemia, the mean percentage cell loss of IHCs was 6.4% in the basal turn, 6.4% in the second turn, and 0.8% in the apical turn, respectively, and the number of SGC neurons had decreased to 89% of preischemic status. These results indicate that transient ischemia causes delayed hearing loss and cell death in the cochlea by day 7 after ischemia.
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MESH Headings
- Action Potentials
- Animals
- Auditory Threshold
- Cell Death
- Cochlear Diseases/etiology
- Cochlear Diseases/pathology
- Cochlear Diseases/physiopathology
- Disease Models, Animal
- Disease Progression
- Gerbillinae
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Inner/ultrastructure
- Hair Cells, Auditory, Outer/pathology
- Hair Cells, Auditory, Outer/ultrastructure
- Hearing Loss, Sensorineural/diagnosis
- Hearing Loss, Sensorineural/etiology
- Hearing Loss, Sensorineural/physiopathology
- Neurons/pathology
- Organ of Corti/blood supply
- Organ of Corti/pathology
- Organ of Corti/physiopathology
- Reperfusion Injury/complications
- Reperfusion Injury/pathology
- Reperfusion Injury/physiopathology
- Spiral Ganglion/pathology
- Vertebral Artery/physiopathology
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Affiliation(s)
- Kenichiro Koga
- Department of Otolaryngology, Ehime University School of Medicine, Ehime, 791-0295 Japan.
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35
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Taniguchi M, Hakuba N, Koga K, Watanabe F, Hyodo J, Gyo K. Apoptotic hair cell death after transient cochlear ischemia in gerbils. Neuroreport 2002; 13:2459-62. [PMID: 12499849 DOI: 10.1097/00001756-200212200-00017] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The mechanisms of cochlear hair cell death following exposure to transient inner ear ischemia were investigated in gerbils histologically. The animals were subjected to ischemic insult by occluding both vertebral arteries for 15 min. Hoechst 33342 nuclear staining showed that inner hair cells (IHCs) underwent sporadic degeneration via nuclear condensation, which peaked 12 hours after the ischemia. Furthermore, nuclear DNA fragmentation was noted by the terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-biotin nick end labeling method. Transmission electron microscopy revealed morphological changes in the IHCs characteristic of apoptosis, including karyopyknosis, chromatin condensation. These findings suggest that apoptotic cell death is the major process in hair cell degeneration in this animal model.
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Affiliation(s)
- Masafumi Taniguchi
- Department of Otolaryngology, Ehime University School of Medicine, Ehime, Shigenobu-cho, Onsen-gun, Ehime 79100295, Japan.
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36
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Hyodo J, Hakuba N, Koga K, Watanabe F, Shudou M, Taniguchi M, Gyo K. Hypothermia reduces glutamate efflux in perilymph following transient cochlear ischemia. Neuroreport 2001; 12:1983-7. [PMID: 11435934 DOI: 10.1097/00001756-200107030-00041] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effect of hypothermia on ischemic injury of the cochlea in gerbils was studied with particular regard to glutamate efflux in the perilymph. Under normothermic conditions interruption of the blood supply to the cochlea for 15 min caused a remarkable elevation of the compound action potential (CAP) threshold, and an increase in perilymphatic glutamate. The CAP threshold recovered to some extent with reperfusion, but not to preischemic levels. CAP thresholds, under hypothermic conditions and with reperfusion, recovered promptly to near pre-ischemic levels, while glutamate concentration did not change. These results, together with electron microscopy studies, suggest that hypothermia prevents hearing loss primarily through reduction of glutamate efflux at the synopses between inner hair cells and primary afferent auditory neurons.
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MESH Headings
- Animals
- Cochlea/pathology
- Cochlea/physiopathology
- Cochlea/ultrastructure
- Cochlear Diseases/pathology
- Cochlear Diseases/physiopathology
- Cochlear Diseases/therapy
- Deafness/metabolism
- Deafness/physiopathology
- Deafness/therapy
- Disease Models, Animal
- Female
- Gerbillinae
- Glutamic Acid/metabolism
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Inner/ultrastructure
- Hypothermia, Induced
- Ischemic Attack, Transient/metabolism
- Ischemic Attack, Transient/physiopathology
- Ischemic Attack, Transient/therapy
- Microscopy, Electron
- Neurons, Afferent/metabolism
- Neurons, Afferent/pathology
- Neurons, Afferent/ultrastructure
- Perilymph/metabolism
- Reperfusion Injury/metabolism
- Reperfusion Injury/physiopathology
- Reperfusion Injury/therapy
- Synapses/metabolism
- Synapses/pathology
- Synapses/ultrastructure
- Vertebrobasilar Insufficiency/metabolism
- Vertebrobasilar Insufficiency/physiopathology
- Vertebrobasilar Insufficiency/therapy
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Affiliation(s)
- J Hyodo
- Department of Otolaryngology, Ehime University School of Medicine, Shigenobu-cho, Onsen-gun, Ehime 791-0295, Japan
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37
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Watanabe F, Koga K, Hakuba N, Gyo K. Hypothermia prevents hearing loss and progressive hair cell loss after transient cochlear ischemia in gerbils. Neuroscience 2001; 102:639-45. [PMID: 11226700 DOI: 10.1016/s0306-4522(00)00510-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The effects of hypothermia on ischemia-reperfusion injury of the cochlea were studied in gerbils. Hearing was assessed by sequentially recording compound action potentials before, during and after the ischemia. The degree of hair cell loss in the organ of Corti was evaluated in specimens stained with rhodamine-phalloidin and the dye Hoechst 33342. Ischemic insult was applied to the animals by occluding the bilateral vertebral arteries for 15 min under normothermic or hypothermic (rectal temperature 32 degrees C) conditions. Interruption of the blood supply to the cochlea caused a tremendous increase in the compound action potential threshold, which usually recovered to some extent with reperfusion. In the ischemia/normothermic group, the threshold did not return to the pre-ischemic level. The average increase in the threshold seven days after ischemia was 20.0 dB. Histologically, the hair cell loss increased gradually until four days after the ischemic insult. On the seventh day, the mean loss of inner and outer hair cells at the basal turn was 31.1 % and 2.4 %, respectively. In the ischemia/hypothermic group, the threshold returned to the pre-ischemic level within 30 min after reperfusion and remained stable thereafter. The mean loss of inner and outer hair cells on the seventh day was 0.1 % and 0.2 %, respectively. These results indicate that hypothermia can prevent inner ear damage, which otherwise occurs after transient ischemia of the cochlea.
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Affiliation(s)
- F Watanabe
- Department of Otolaryngology, Ehime University School of Medicine, Shigenobu-cho, Onsen-gun, 791-0295, Japan.
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