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Rose KP, Manilla G, Milon B, Zalzman O, Song Y, Coate TM, Hertzano R. Spatially distinct otic mesenchyme cells show molecular and functional heterogeneity patterns before hearing onset. iScience 2023; 26:107769. [PMID: 37720106 PMCID: PMC10502415 DOI: 10.1016/j.isci.2023.107769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 06/29/2023] [Accepted: 08/25/2023] [Indexed: 09/19/2023] Open
Abstract
The cochlea consists of diverse cellular populations working in harmony to convert mechanical stimuli into electrical signals for the perception of sound. Otic mesenchyme cells (OMCs), often considered a homogeneous cell type, are essential for normal cochlear development and hearing. Despite being the most numerous cell type in the developing cochlea, OMCs are poorly understood. OMCs are known to differentiate into spatially and functionally distinct cell types, including fibrocytes of the lateral wall and spiral limbus, modiolar osteoblasts, and specialized tympanic border cells of the basilar membrane. Here, we show that OMCs are transcriptionally and functionally heterogeneous and can be divided into four distinct populations that spatially correspond to OMC-derived cochlear structures. We also show that this heterogeneity and complexity of OMCs commences during early phases of cochlear development. Finally, we describe the cell-cell communication network of the developing cochlea, inferring a major role for OMC in outgoing signaling.
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Affiliation(s)
- Kevin P. Rose
- Neurotology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gabriella Manilla
- Neurotology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Beatrice Milon
- Neurotology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ori Zalzman
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Yang Song
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Thomas M. Coate
- Department of Biology, Georgetown University, Washington, DC 20007, USA
| | - Ronna Hertzano
- Neurotology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Otorhinolaryngology Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Zhang Y, Neng L, Sharma K, Hou Z, Johnson A, Song J, Dabdoub A, Shi X. Pericytes control vascular stability and auditory spiral ganglion neuron survival. eLife 2023; 12:e83486. [PMID: 36719173 PMCID: PMC9940910 DOI: 10.7554/elife.83486] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/26/2023] [Indexed: 02/01/2023] Open
Abstract
The inner ear has a rich population of pericytes, a multi-functional mural cell essential for sensory hair cell heath and normal hearing. However, the mechanics of how pericytes contribute to the homeostasis of the auditory vascular-neuronal complex in the spiral ganglion are not yet known. In this study, using an inducible and conditional pericyte depletion mouse (PDGFRB-CreERT2; ROSA26iDTR) model, we demonstrate, for the first time, that pericyte depletion causes loss of vascular volume and spiral ganglion neurons (SGNs) and adversely affects hearing sensitivity. Using an in vitro trans-well co-culture system, we show pericytes markedly promote neurite and vascular branch growth in neonatal SGN explants and adult SGNs. The pericyte-controlled neural growth is strongly mediated by pericyte-released exosomes containing vascular endothelial growth factor-A (VEGF-A). Treatment of neonatal SGN explants or adult SGNs with pericyte-derived exosomes significantly enhances angiogenesis, SGN survival, and neurite growth, all of which were inhibited by a selective blocker of VEGF receptor 2 (Flk1). Our study demonstrates that pericytes in the adult ear are critical for vascular stability and SGN health. Cross-talk between pericytes and SGNs via exosomes is essential for neuronal and vascular health and normal hearing.
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Affiliation(s)
- Yunpei Zhang
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Lingling Neng
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Kushal Sharma
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Zhiqiang Hou
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Anatasiya Johnson
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Junha Song
- Life Sciences Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Alain Dabdoub
- Biological Sciences, Sunnybrook Research InstituteTorontoCanada
- Department of Otolaryngology-Head & Neck Surgery, University of TorontoTorontoCanada
- Department of Laboratory Medicine and Pathobiology, University of TorontoTorontoCanada
| | - Xiaorui Shi
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
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Hori T, Sugahara K, Tsuda J, Hirose Y, Hashimoto M, Takemoto Y, Tarumoto S, Yamashita H. Oral administration of an herbal medicine to prevent progressive hearing loss in a mouse model of diabetes. Auris Nasus Larynx 2019; 46:703-708. [PMID: 30799140 DOI: 10.1016/j.anl.2019.01.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/10/2019] [Accepted: 01/21/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Tsumura Suzuki Obese Diabetes (TSOD) mice exhibit early age-associated hearing loss. Histopathological analysis of these mice shows narrowing of capillaries in the stria vascularis and chronic reduction of blood flow in the cochlea. In this study, we investigated the effect of oral administration of a herbal medicine or calorie restriction on hearing in TSOD mice. METHODS TSOD mice were divided into 4 groups: CR (calorie restriction), BF and DS (treated with the herbal medicines, Bofutsushosan and Daisaikoto, respectively), and the control group. Body weight, blood glucose levels, and auditory brainstem responses (ABRs) were measured. The cochleae were excised and evaluated histopathologically. RESULTS Blood glucose levels were suppressed in the CR, BF, and DS groups. In addition, the elevation of ABR thresholds was inhibited in the CR, BF, and DS groups. Cochlear blood vessels remained wide in the three treatment groups compared with the control group. These results suggested that the administration of these herbal medicines improved glucose tolerance and yielded results similar to those on calorie restriction. CONCLUSION Oral administration of 2 herbal medicines can prevent hearing function disorder in a model mouse of diabetes. The results may clarify the possibility of clinical application.
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Affiliation(s)
- Takeshi Hori
- Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Kazuma Sugahara
- Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Junko Tsuda
- Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Yoshinobu Hirose
- Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Makoto Hashimoto
- Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Yousuke Takemoto
- Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Shunsuke Tarumoto
- Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Hiroshi Yamashita
- Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan.
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Microvascular networks in the area of the auditory peripheral nervous system. Hear Res 2019; 371:105-116. [DOI: 10.1016/j.heares.2018.11.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/14/2018] [Accepted: 11/28/2018] [Indexed: 12/20/2022]
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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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Lee JJ, Jang JH, Choo OS, Lim HJ, Choung YH. Steroid intracochlear distribution differs by administration method: Systemic versus intratympanic injection. Laryngoscope 2017; 128:189-194. [PMID: 28304075 DOI: 10.1002/lary.26562] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 01/13/2017] [Accepted: 02/07/2017] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Steroids have been widely used to treat inner-ear diseases such as sudden sensorineural hearing loss, tinnitus, and Meniere's disease. They can be given via either systemic or intratympanic (IT) injection. The purpose of the present study was to explore differences in intracochlear steroid distribution by the administration method employed (systemic vs. IT injection). STUDY DESIGN Animal study. METHODS Twenty-three Sprague-Dawley rats were given fluorescein isothiocyanate-labeled dexamethasone (FITC-DEX) three times (on successive days) via intraperitoneal (IP) or IT injection. Cochlear uptake of FITC-DEX was evaluated via immunohistochemistry and flow cytometry at 6 hours, and 3 and 7 days after the final injection. RESULTS FITC-DEX uptake was evident in spiral ganglion cells (SGs), the organ of Corti (OC), and the lateral walls (LWs), the basal turns of which were stained relatively prominently in both groups. Animals receiving IP injections exhibited higher FITC-DEX uptakes by the SGs and OC, whereas IT injection triggered higher-level FITC-DEX accumulation by the OC and LWs. Flow cytometry revealed that intracochlear FITC-DEX uptake by IT-injected animals was higher and more prolonged than in animals subjected to IP injections. CONCLUSION We thus describe differences in cochlear steroid distributions after systemic and IT injections. This finding could help our understanding of the pharmacokinetics of steroids in the cochlea. LEVEL OF EVIDENCE NA. Laryngoscope, 128:189-194, 2018.
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Affiliation(s)
- Jong Joo Lee
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Jeong Hun Jang
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Oak-Sung Choo
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Republic of Korea
| | | | - Yun-Hoon Choung
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Republic of Korea.,Bk21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
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Nakashima T, Hattori T, Sone M, Sato E, Tominaga M, Sugiura M. Blood Flow in the Ears of Patients Receiving Cochlear Implants. Ann Otol Rhinol Laryngol 2016; 113:426-30. [PMID: 15224823 DOI: 10.1177/000348940411300602] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We measured cochlear blood flow (CBF) in 55 patients who received cochlear implants, using a laser-Doppler probe placed over the site of drilling in the cochlear bony wall. The subjects included 29 patients with congenital deafness of unknown cause, 8 with idiopathic progressive sensorineural hearing loss, 4 with postmeningitic deafness, 3 with Waardenburg's syndrome, 3 with congenital cytomegalovirus infection, and 8 whose deafness had other causes. There was a wide range of CBF values in patients with congenital deafness of unknown cause. In the patients with idiopathic progressive sensorineural hearing loss, the CBF was significantly lower in patients more than 40 years old. Intracochlear calcification following meningitis appears to be associated with a reduced CBF.
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Affiliation(s)
- Tsutomu Nakashima
- Department of Otorhinolaryngology, Nagoya University School of Medicine, Nagoya, Japan
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Bertlich M, Ihler F, Sharaf K, Weiss BG, Strupp M, Canis M. Betahistine metabolites, Aminoethylpyridine, and Hydroxyethylpyridine increase cochlear blood flow in guinea pigsin vivo. Int J Audiol 2014; 53:753-9. [DOI: 10.3109/14992027.2014.917208] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Yamanaka T, Murai T, Sawai Y, Okamoto H, Hosoi H. The effect of prostaglandin E1 on brainstem blood flow disturbance in an animal model of vertebrobasilar insufficiency. Eur Arch Otorhinolaryngol 2013; 271:947-51. [PMID: 23591797 DOI: 10.1007/s00405-013-2489-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 04/08/2013] [Indexed: 11/25/2022]
Abstract
Using an animal model of vertebrobasilar insufficiency (VBI), in which brainstem circulatory disturbance was induced in rats, we examined how prostaglandin E1 (PG-E1) affects brainstem blood flow (BBF) to clarify whether it is effective against VBI. Fifteen healthy male Wister rats that displayed positive responses to Preyer's reflex were used. Their BBF was continuously measured on the left side of the midline of the brainstem using laser Doppler flowmetry. A rat model of VBI, a pathological condition that presents with decreased BBF, was prepared by applying a vertebral artery clamp ipsilateral to the BBF measuring site and inducing hypotension of 60-70 mmHg by blood withdrawal. Saline as a control (n = 5), 5 ng/kg/min (n = 5) or 10 ng/kg/min (n = 5) PG-E1 at a dose was continuously administered to the rats using a motor-driven syringe pump. The effects of the drugs on the rats' BBF were evaluated. BBF, which was decreased by the unilateral vertebral artery clamping combined with blood withdrawal-induced hypotension, recovered in a dose-dependent manner after the administration of 5 or 10 ng/kg/min PG-E1, and complete recovery to the baseline level was achieved by 60 min treatment; however, no such effect was observed for intravenous saline. These results suggest that PG-E1 acts on local vessels and improves blood flow insufficiency in the brainstem in our animal model of VBI. PG-E1 might be useful as a cerebral vasodilator for VBI.
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Affiliation(s)
- Toshiaki Yamanaka
- Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine, 840 Shijo, Kashihara, Nara, 634-8522, Japan,
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Ihler F, Bertlich M, Sharaf K, Strieth S, Strupp M, Canis M. Betahistine exerts a dose-dependent effect on cochlear stria vascularis blood flow in guinea pigs in vivo. PLoS One 2012; 7:e39086. [PMID: 22745706 PMCID: PMC3380058 DOI: 10.1371/journal.pone.0039086] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 05/18/2012] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE Betahistine is a histamine H(1)-receptor agonist and H(3)-receptor antagonist that is administered to treat Menière's disease. Despite widespread use, its pharmacological mode of action has not been entirely elucidated. This study investigated the effect of betahistine on guinea pigs at dosages corresponding to clinically used doses for cochlear microcirculation. METHODS Thirty healthy Dunkin-Hartley guinea pigs were randomly assigned to five groups to receive betahistine dihydrochloride in a dose of 1,000 mg/kg b. w. (milligram per kilogram body weight), 0.100 mg/kg b. w., 0.010 mg/kg b. w., 0.001 mg/kg b. w. in NaCl 0.9% or NaCl 0.9% alone as placebo. Cochlear blood flow and mean arterial pressure were continuously monitored by intravital fluorescence microscopy and invasive blood pressure measurements 3 minutes before and 15 minutes after administration of betahistine. RESULTS When betahistine was administered in a dose of 1.000 mg/kg b. w. cochlear blood flow was increased to a peak value of 1.340 arbitrary units (SD: 0.246; range: 0.933-1.546 arb. units) compared to baseline (p<0.05; Two Way Repeated Measures ANOVA/Bonferroni t-test). The lowest dosage of 0.001 mg/kg b. w. betahistine or NaCl 0.9% had the same effect as placebo. Nonlinear regression revealed that there was a sigmoid correlation between increase in blood flow and dosages. CONCLUSIONS Betahistine has a dose-dependent effect on the increase of blood flow in cochlear capillaries. The effects of the dosage range of betahistine on cochlear microcirculation corresponded well to clinically used single dosages to treat Menière's disease. Our data suggest that the improved effects of higher doses of betahistine in the treatment of Menière's disease might be due to a corresponding increase of cochlear blood flow.
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Affiliation(s)
- Fritz Ihler
- Department of Otorhinolaryngology, Head and Neck Surgery, Goettingen University Medical School, Göttingen, Germany
- Integrated Center for Research and Treatment of Vertigo, Balance and Ocular Motor Disorders, University of Munich Hospital, Munich, Germany
- Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
| | - Mattis Bertlich
- Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
| | - Kariem Sharaf
- Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
| | - Sebastian Strieth
- Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
- Department of Otorhinolaryngology, Head & Neck Surgery, J. W. Goethe-University-Medical School, Frankfurt/Main, Germany
| | - Michael Strupp
- Integrated Center for Research and Treatment of Vertigo, Balance and Ocular Motor Disorders, University of Munich Hospital, Munich, Germany
- Department of Neurology, University of Munich Hospital, Munich, Germany
| | - Martin Canis
- Department of Otorhinolaryngology, Head and Neck Surgery, Goettingen University Medical School, Göttingen, Germany
- Integrated Center for Research and Treatment of Vertigo, Balance and Ocular Motor Disorders, University of Munich Hospital, Munich, Germany
- Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
- * E-mail:
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Subhash HM, Davila V. Volumetric in vivo imaging of microvascular perfusion within the intact cochlea in mice using ultra-high sensitive optical microangiography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2011; 30:224-30. [PMID: 20813632 PMCID: PMC3005144 DOI: 10.1109/tmi.2010.2072934] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Studying the inner ear microvascular dynamics is extremely important to understand the cochlear function and to further advance the diagnosis, prevention, and treatment of many otologic disorders. However, there is currently no effective imaging tool available that is able to access the blood flow within the intact cochlea. In this paper, we report the use of an ultrahigh sensitive optical micro-angiography (UHS-OMAG) imaging system to image 3-D microvascular perfusion within the intact cochlea in living mice. The UHS-OMAG image system used in this study is based on spectral domain optical coherence tomography, which uses a broadband light source centered at 1300 nm with an imaging rate of 47[Formula: see text] 000 A-scans/s, capable of acquiring high-resolution B scans at 300 frames/s. The technique is sensitive enough to image very slow blood flow velocities, such as those found in capillary networks. The 3-D imaging acquisition time for a whole cochlea is ∼ 4.1 s. We demonstrate that volumetric reconstruction of microvascular flow obtained by UHS-OMAG provides a comprehensive perfusion map of several regions of the cochlea, including the otic capsule, the stria vascularis of the apical and middle turns and the radiating arterioles that emanate from the modiolus.
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Affiliation(s)
- Hrebesh M. Subhash
- Biophotonics and imaging lab, Division of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR 97239 USA (; )
| | - Viviana Davila
- Biophotonics and imaging lab, Division of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR 97239 USA (; )
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Otake H, Yamamoto H, Teranishi M, Sone M, Nakashima T. Cochlear blood flow during occlusion and reperfusion of the anterior inferior cerebellar artery--effect of topical application of dexamethasone to the round window. Acta Otolaryngol 2009; 129:127-31. [PMID: 18607911 DOI: 10.1080/00016480802078119] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
CONCLUSION Topical application of dexamethasone may support autoregulation of cochlear blood flow (CBF), although it had no direct effect on CBF. OBJECTIVES Although intratympanic steroid therapy for patients with inner ear disorders is common, the mechanism by which steroids exert their effect is unclear. We investigated the response of CBF to topical application of dexamethasone onto the round window. MATERIALS AND METHODS Two concentrations of dexamethasone (3.3 mg/ml and 33 mg/ml dexamethasone in 0.5 microl saline) were applied to the round windows of rats, and CBF responses were measured using a laser Doppler flowmeter. The effects on CBF of a 2 h occlusion of the anterior inferior cerebellar artery (AICA) and subsequent release of the clamp with or without previous dexamethasone application were investigated. RESULTS No significant change in CBF was observed after topical application of dexamethasone, and it did not affect the decrease in CBF caused by AICA occlusion. However, recovery of CBF after release of the AICA clamp was better in animals treated with dexamethasone than in those that did not receive dexamethasone.
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Monfared A, Blevins NH, Cheung ELM, Jung JC, Popelka G, Schnitzer MJ. In vivo imaging of mammalian cochlear blood flow using fluorescence microendoscopy. Otol Neurotol 2007; 27:144-52. [PMID: 16436982 PMCID: PMC2820368 DOI: 10.1097/01.mao.0000190708.44067.b0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
AIMS We sought to develop techniques for visualizing cochlear blood flow in live mammalian subjects using fluorescence microendoscopy. BACKGROUND Inner ear microcirculation appears to be intimately involved in cochlear function. Blood velocity measurements suggest that intense sounds can alter cochlear blood flow. Disruption of cochlear blood flow may be a significant cause of hearing impairment, including sudden sensorineural hearing loss. However, inability to image cochlear blood flow in a nondestructive manner has limited investigation of the role of inner ear microcirculation in hearing function. Present techniques for imaging cochlear microcirculation using intravital light microscopy involve extensive perturbations to cochlear structure, precluding application in human patients. The few previous endoscopy studies of the cochlea have suffered from optical resolution insufficient for visualizing cochlear microvasculature. Fluorescence microendoscopy is an emerging minimally invasive imaging modality that provides micron-scale resolution in tissues inaccessible to light microscopy. In this article, we describe the use of fluorescence microendoscopy in live guinea pigs to image capillary blood flow and movements of individual red blood cells within the basal turn of the cochlea. METHODS We anesthetized eight adult guinea pigs and accessed the inner ear through the mastoid bulla. After intravenous injection of fluorescein dye, we made a limited cochleostomy and introduced a compound doublet gradient refractive index endoscope probe 1 mm in diameter into the inner ear. We then imaged cochlear blood flow within individual vessels in an epifluorescence configuration using one-photon fluorescence microendoscopy. RESULTS We observed single red blood cells passing through individual capillaries in several cochlear structures, including the round window membrane, spiral ligament, osseous spiral lamina, and basilar membrane. Blood flow velocities within inner ear capillaries varied widely, with observed speeds reaching up to approximately 500 microm/s. CONCLUSION Fluorescence microendoscopy permits visualization of cochlear microcirculation with micron-scale optical resolution and determination of blood flow velocities through analysis of video sequences.
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Affiliation(s)
- Ashkan Monfared
- Department of Otolaryngology–Head and Neck Surgery, Stanford University, Stanford, California, U.S.A
| | - Nikolas H. Blevins
- Department of Otolaryngology–Head and Neck Surgery, Stanford University, Stanford, California, U.S.A
| | - Eunice L. M. Cheung
- Department of Otolaryngology–Head and Neck Surgery, Stanford University, Stanford, California, U.S.A
- Department of Biological Sciences, Stanford University, Stanford, California, U.S.A
- Department of Applied Physics, Stanford University, Stanford, California, U.S.A
| | - Juergen C. Jung
- Department of Biological Sciences, Stanford University, Stanford, California, U.S.A
- Department of Applied Physics, Stanford University, Stanford, California, U.S.A
- Department of Pharmacology, Oxford University, Oxford, U.K
| | - Gerald Popelka
- Department of Otolaryngology–Head and Neck Surgery, Stanford University, Stanford, California, U.S.A
| | - Mark J. Schnitzer
- Department of Biological Sciences, Stanford University, Stanford, California, U.S.A
- Department of Applied Physics, Stanford University, Stanford, California, U.S.A
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Yavuz E, Morawski K, Telischi FF, Ozdamar O, Delgado RE, Manns F, Parel JM. Simultaneous measurement of electrocochleography and cochlear blood flow during cochlear hypoxia in rabbits. J Neurosci Methods 2005; 147:55-64. [PMID: 16054516 PMCID: PMC1769333 DOI: 10.1016/j.jneumeth.2005.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Revised: 03/17/2005] [Accepted: 03/21/2005] [Indexed: 10/25/2022]
Abstract
In this study, a new monitoring system is developed to measure cochlear blood flow (CBF) and electrocochleography (ECochG) during transient ischemic episodes of the cochlea. A newly designed otic probe was used for the simultaneous recordings of laser-Doppler CBF and ECochG directly from the round window (RW). The probe enabled the recording of high amplitude compound action potentials (CAP) and cochlear microphonics (CM) with few averages. Experiments were conducted on rabbits to generate episodes of cochlear ischemia by using timed compressions of the internal auditory artery (IAA). The computer monitoring system extracted and measured CAP and CM components from ECochG in real-time. Results indicate that CM and CAP generally followed CBF during compressions and releases of IAA. Both CBF values and CAP amplitudes showed an overshoot following the reperfusion. CAP amplitude measures were found to be very sensitive to ischemia showing very rapid amplitude, latency and morphological changes. CM amplitude decreased more slowly than the CAP and CBF. Simultaneous recordings of CBF and ECochG using the otic probe provide a valuable neuromonitoring tool to investigate the dynamic behavior of the cochlea during ischemia.
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Affiliation(s)
- Erdem Yavuz
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL 33124, USA.
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Yamamoto H, Tominaga M, Sone M, Nakashima T. Contribution of stapedial artery to blood flow in the cochlea and its surrounding bone. Hear Res 2004; 186:69-74. [PMID: 14644460 DOI: 10.1016/s0378-5955(03)00310-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This study was performed to elucidate the contribution of the stapedial artery (SA)--which has been considered to be independent of the vertebrobasilar system--to blood flow in the ear by observing ear blood flow in Sprague-Dawley rats. A laser-Doppler (LD) probe was positioned on the bony wall of the cochlear basal turn after removal of the middle ear mucosa. The LD output was measured while either or both the SA and the anterior inferior cerebellar artery (AICA) were occluded. The LD output decreased to 70.6+/-2.5% (mean+/-S.D.) of the baseline value following SA occlusion, and to 58.0+/-7.8% following AICA occlusion in 12 animals. The rebound phenomenon of blood flow, which is a type of autoregulation, was only observed after releasing AICA occlusion. Simultaneous occlusion of the SA and AICA decreased the LD output to 27.0+/-5.5% of the baseline value. The role of the contribution of the SA and AICA to the LD output is discussed.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Otorhinolaryngology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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16
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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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17
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Nakashima T, Hattori T, Sone M, Sato E, Tominaga M. Blood flow measurements in the ears of patients receiving cochlear implants. Ann Otol Rhinol Laryngol 2002; 111:998-1001. [PMID: 12450173 DOI: 10.1177/000348940211101108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We measured cochlear blood flow in 12 patients who received cochlear implants, using a laser-Doppler probe with an outer diameter of 0.8 mm. The subjects had congenital deafness, idiopathic progressive sensorineural hearing loss, Waardenburg's syndrome, narrow internal auditory canal, or sudden deafness. Putting the probe tip to the site of drilling for cochlear implantation, we measured blood flow before, during, and after the cochlear bony wall was opened. The laser-Doppler output was confirmed even after the tip of the probe was inserted into the perilymphatic space in all cases. Our results revealed that blood flow was maintained in all cochleas, although there was a probability of reduction in blood flow volume. We conclude that laser-Doppler flowmetry is both relatively safe and useful for measuring blood flow in the ears during cochlear implantation procedures.
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Affiliation(s)
- Tsutomu Nakashima
- Department of Otorhinolaryngology, Nagoya University School of Medicine, Nagoya, Japan
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