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Ishiyama G, Wester J, Lopez IA, Beltran-Parrazal L, Ishiyama A. Oxidative Stress in the Blood Labyrinthine Barrier in the Macula Utricle of Meniere's Disease Patients. Front Physiol 2018; 9:1068. [PMID: 30233382 PMCID: PMC6129601 DOI: 10.3389/fphys.2018.01068] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 07/17/2018] [Indexed: 12/13/2022] Open
Abstract
The blood labyrinthine barrier (BLB) is critical in the maintenance of inner ear ionic and fluid homeostasis. Recent studies using imaging and histopathology demonstrate loss of integrity of the BLB in the affected inner ear of Meniere's disease (MD) patients. We hypothesized that oxidative stress is involved in the pathogenesis of BLB degeneration, and to date there are no studies of oxidative stress proteins in the human BLB. We investigated the ultrastructural and immunohistochemical changes of the BLB in the vestibular endorgan, the macula utricle, from patients with MD (n = 10), acoustic neuroma (AN) (n = 6) and normative autopsy specimens (n = 3) with no inner ear disease. Each subject had a well-documented clinical history and audiovestibular testing. Utricular maculae were studied using light and transmission electron microscopy and double labeling immunofluorescence. Vascular endothelial cells (VECs) were identified using isolectin B4 (IB4) and glucose-transporter-1 (GLUT-1). Pericytes were identified using alpha smooth muscle actin (αSMA) and phalloidin. IB4 staining of VECS was consistently seen in both AN and normative. In contrast, IB4 was nearly undetectable in all MD specimens, consistent with the significant VEC damage confirmed on transmission electron microscopy. GLUT-1 was present in MD, AN, and normative. αSMA and phalloidin were expressed consistently in the BLB pericytes in normative, AN specimen, and Meniere's specimens. Endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and nitrotyrosine were used as markers of oxidative stress. The VECs of the BLB in Meniere's had significantly higher levels of expression of iNOS and nitrotyrosine compared with normative and AN specimen. eNOS-IF staining showed similar patterns in normative and Meniere's specimens. Microarray-based gene expression profiling confirmed upregulation of iNOS mRNA from the macula utricle of Meniere's patients compared with AN. Nitrotyrosine, a marker recognized as a hallmark of inflammation, especially when seen in association with an upregulation of iNOS, was detected in the epithelial and stromal cells in addition to VECs in MD. Immunohistochemical and ultrastructural degenerative changes of the VEC suggest that these cells are the primary targets of oxidative stress, and pericyte pathology including degeneration and migration, likely also plays a role in the loss of integrity of the BLB and triggering of inflammatory pathways in MD. These studies advance our scientific understanding of oxidative stress in the human inner ear BLB and otopathology.
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Affiliation(s)
- Gail Ishiyama
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Jacob Wester
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Ivan A. Lopez
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Luis Beltran-Parrazal
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
- Centro de Investigaciones Cerebrales, Universidad Veracruzana, Xalapa, Mexico
| | - Akira Ishiyama
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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Fitzakerley JL, Trachte GJ. Genetics of guanylyl cyclase pathways in the cochlea and their influence on hearing. Physiol Genomics 2018; 50:780-806. [PMID: 29958079 DOI: 10.1152/physiolgenomics.00056.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although hearing loss is the most common sensory deficit in Western societies, there are no successful pharmacological treatments for this disorder. Recent experiments have demonstrated that manipulation of intracellular cyclic guanosine monophosphate (cGMP) concentrations can have both beneficial and harmful effects on hearing. In this review, we will examine the role of cGMP as a key second messenger involved in many aspects of cochlear function and discuss the known functions of downstream effectors of cGMP in sound processing. The nitric oxide-stimulated soluble guanylyl cyclase system (sGC) and the two natriuretic peptide-stimulated particulate GCs (pGCs) will be more extensively covered because they have been studied most thoroughly. The cochlear GC systems are attractive targets for medical interventions that improve hearing while simultaneously representing an under investigated source of sensorineural hearing loss.
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Affiliation(s)
- Janet L Fitzakerley
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
| | - George J Trachte
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
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Gentamicin alters Akt-expression and its activation in the guinea pig cochlea. Neuroscience 2015; 311:490-8. [PMID: 26528886 DOI: 10.1016/j.neuroscience.2015.10.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 10/05/2015] [Accepted: 10/27/2015] [Indexed: 01/11/2023]
Abstract
Gentamicin treatment induces hair cell death or survival in the inner ear. Besides the well-known toxic effects, the phosphatidylinositol-3 kinase/Akt (PI3K/Akt) pathway was found to be involved in cell protection. After gentamicin application, the spatiotemporal expression patterns of Akt and its activated form (p-Akt) were determined in male guinea pigs. A single dose of 0.1 mL gentamicin (4 mg/ear/animal) was intratympanically injected. The auditory brainstem responses (ABRs) were recorded prior to application and 1, 2 and 7 days afterward. At these three time points the cochleae (n=10 in each case) were removed, transferred to fixative and embedded in paraffin. Seven ears were used as untreated controls. Gentamicin, Akt and p-Akt were identified immunohistochemically in various regions of the cochlea and their staining intensities were quantified on sections using digital image analysis. The application of gentamicin resulted in hearing loss with a concomitant up-regulation of Akt-expression in the organ of Corti and spiral ganglion cells and an additional activation in spiral ganglion cells. At the level of individual ears, clear intracellular correlations were found between Akt- and p-Akt-expression in the stria vascularis and interdental cells and, to a minor extent, in the spiral ligament and the organ of Corti. Furthermore, statistical evidence for the connection between gentamicin up-take and hearing loss was detected. The increase in Akt- and p-Akt-expression in the organ of Corti and spiral ganglion cells indicates a selected response of the cochlea against gentamicin toxicity.
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Heinrich UR, Schmidtmann I, Strieth S, Helling K. Cell-specific accumulation patterns of gentamicin in the guinea pig cochlea. Hear Res 2015; 326:40-8. [PMID: 25882166 DOI: 10.1016/j.heares.2015.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 03/19/2015] [Accepted: 03/20/2015] [Indexed: 11/24/2022]
Abstract
Intratympanic gentamicin therapy has become a popular treatment modality for Ménière's disease (MD) through controlled elimination of vertigo spells caused by the balance organ. However, the known ototoxic properties of aminoglycosides lead to cochlear damage. In order to gain more information about cellular preferences for aminoglycoside accumulation within the cochlea, gentamicin was immuno histochemically localized by light microscopy in male guinea pigs 1 and 7 days after intratympanic application (n = 8 ears/incubation time). Differences in the gentamicin-specific cellular storage capacities were quantified by determination of the local immuno staining intensities. Gentamicin was detected in every cochlear cell type, but with spatiotemporal variability. One day after application, an intense staining reaction was found in all cell types except the spiral ganglion cells and the stria vascularis. Six days later, gentamicin staining intensities were additionally reduced in the nerve fibers and the spiral ligament. Statistic analysis revealed strong cellular associations in respect to aminoglycoside accumulation. Furthermore, associations with recorded hearing losses were identified comparing the cellular gentamicin content in the organ of Corti, in the stria vascularis, in the spiral ganglion cells and in fibrocytes of the Limbus. In the lateral wall, clear differences in cellular gentamicin accumulation were found between type I fibrocytes of the spiral ligament compared with basal and intermediate cells of the stria vascularis. This finding was unexpected as these three cell types belong to a well-developed gap-junction system which normally enables unhampered cell communication. Cellular differences in local gentamicin storage capacities, transport processes and inherent diffusion barriers are discussed.
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Affiliation(s)
- Ulf-Rüdiger Heinrich
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Germany
| | - Irene Schmidtmann
- Institute for Medical Biostatistics, Epidemiology and Informatics, University Medical Center of the Johannes Gutenberg University Mainz, Germany
| | - Sebastian Strieth
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Germany
| | - Kai Helling
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Germany.
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Yonamine FK, Onishi ET, Mouro MG, Higa EMS, Cruz OLM. Nitric oxide levels in cochlear fluids of guinea pig. Acta Cir Bras 2013; 28:397-402. [PMID: 23702944 DOI: 10.1590/s0102-86502013000500013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 04/14/2013] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To describe a technique to obtain guinea pigs cochlear fluids and measure nitric oxide (NO) concentration. METHODS Six guinea pigs were used and sacrificed. The cochlear fluids collected for measurement of NO, performed by chemiluminescence (NOA 280). RESULTS Through the chemiluminescence was possible to analyze the concentration of NO in cochlear fluids obtained. Average levels of nitric oxide from guinea pigs was 12.55 µM. CONCLUSION It is possible to obtain nitric oxide cochlear fluids, with this technique and nitric oxide concentration measure by chemiluminescence, a quantitative and more precise method.
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Affiliation(s)
- Fernando Kaoru Yonamine
- Department of Otorhinolaryngology, Head and Neck Surgery, Federal University of Sao Paulo, Brazil.
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Cai J, Li J, Liu W, Han Y, Wang H. Alpha2-adrenergic receptors in spiral ganglion neurons may mediate protective effects of brimonidine and yohimbine against glutamate and hydrogen peroxide toxicity. Neuroscience 2013; 228:23-35. [DOI: 10.1016/j.neuroscience.2012.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 09/29/2012] [Accepted: 10/01/2012] [Indexed: 10/27/2022]
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Heinrich UR, Helling K. Nitric oxide--a versatile key player in cochlear function and hearing disorders. Nitric Oxide 2012; 27:106-16. [PMID: 22659013 DOI: 10.1016/j.niox.2012.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/10/2012] [Accepted: 05/24/2012] [Indexed: 12/13/2022]
Abstract
Nitric oxide (NO) is a signaling molecule which can generally be formed by three nitric oxide synthases (NOS). Two of them, the endothelial nitric oxide synthase (eNOS) and the neural nitric oxide synthase (nNOS), are calcium/calmodulin-dependent and constitutively expressed in many cell types. Both isoforms are found in the vertebrate cochlea. The inducible nitric oxide synthase (iNOS) is independent of calcium and normally not detectable in the un-stimulated cochlea. In the inner ear, as in other tissues, NO was identified as a multitask molecule involved in various processes such as neurotransmission and neuromodulation. In addition, increasing evidence demonstrates that the NO-dependent processes of cell protection or, alternatively, cell destruction seem to depend, among other things, on changes in the local cochlear NO-concentration. These alterations can occur at the cellular level or within a distinct cell population both leading to an NO-imbalance within the hearing organ. This dysfunction can result in hearing loss or even in deafness. In cases of cochlear malfunction, regulatory systems such as the gap junction system, the blood vessels or the synaptic region might be affected temporarily or permanently by an altered NO-level. This review discusses potential cellular mechanisms how NO might contribute to different forms of hearing disorders. Approaches of NO-reduction are evaluated and the transfer of results obtained from experimental animal models to human medication is discussed.
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Affiliation(s)
- Ulf-Rüdiger Heinrich
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center of The Johannes Gutenberg-University Mainz, Germany.
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Inai S, Watanabe KI, Okubo K. Inducible Nitric Oxide Synthase Participates in Cochlear Damage after Acoustic Stimulation in Guinea Pigs. J NIPPON MED SCH 2012; 79:121-8. [DOI: 10.1272/jnms.79.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Shunta Inai
- Department of Head & Neck and Sensory Organ Science, Graduate School of Medicine, Nippon Medical School
| | - Ken-ichi Watanabe
- Department of Head & Neck and Sensory Organ Science, Graduate School of Medicine, Nippon Medical School
| | - Kimihiro Okubo
- Department of Head & Neck and Sensory Organ Science, Graduate School of Medicine, Nippon Medical School
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Doxycycline reduces nitric oxide production in guinea pig inner ears. Auris Nasus Larynx 2011; 38:671-7. [DOI: 10.1016/j.anl.2011.02.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 02/01/2011] [Accepted: 02/02/2011] [Indexed: 11/22/2022]
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EGb 761 (Ginkgo biloba) protects cochlear hair cells against ototoxicity induced by gentamicin via reducing reactive oxygen species and nitric oxide-related apoptosis. J Nutr Biochem 2011; 22:886-94. [DOI: 10.1016/j.jnutbio.2010.08.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 07/29/2010] [Accepted: 08/05/2010] [Indexed: 12/23/2022]
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Helling K, Heinrich UR, Heusgen L, Brieger J, Schmidtmann I, Li H, Mann WJ. Gentamicin alters nitric oxide production in semicircular canals and otolith organs. Laryngoscope 2010; 120:2125-8. [DOI: 10.1002/lary.21075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Dai M, Nuttall A, Yang Y, Shi X. Visualization and contractile activity of cochlear pericytes in the capillaries of the spiral ligament. Hear Res 2009; 254:100-7. [PMID: 19422897 DOI: 10.1016/j.heares.2009.04.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 03/19/2009] [Accepted: 04/27/2009] [Indexed: 10/24/2022]
Abstract
Pericytes, mural cells located on microvessels, are considered to play an important role in the formation of the vasculature and the regulation of local blood flow in some organs. Little is known about the physiology of cochlear pericytes. In order to investigate the function of cochlear pericytes, we developed a method to visualize cochlear pericytes using diaminofluorescein-2 diacetate (DAF-2DA) and intravital fluorescence microscopy. This method can permit the study of the effect of vasoactive agents on pericytes under the in vivo and normal physiological condition. The specificity of the labeling method was verified by the immunofluorescence labeling of pericyte maker proteins such as desmin, neural proteoglycan (NG2), and thymocyte differentiation antigen 1 (Thy-1). Superfused K(+) and Ca(2+) to the cochlear lateral wall resulted in localized constriction of capillaries at pericyte locations both in vivo and in vitro, while there was no obvious change in cochlear capillary diameters with application of the adrenergic neurotransmitter noradrenaline. The method could be an effective way to visualize cochlear pericytes and microvessels and study lateral wall vascular physiology. Moreover, we demonstrate for the first time that cochlear pericytes have contractility, which may be important for regulation of cochlear blood flow.
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Affiliation(s)
- Min Dai
- Oregon Hearing Research Center (NRC04), Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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Liu F, Xia M, Xu A. Expression of VEGF, iNOS, and eNOS is increased in cochlea of diabetic rat. Acta Otolaryngol 2008; 128:1178-86. [PMID: 19241604 DOI: 10.1080/00016480801901774] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
CONCLUSION The results of this study indicate that diabetes causes up-regulation of vascular endothelial growth factor (VEGF), inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS), which may be involved in the pathogenesis of cochlea functional loss. OBJECTIVE To investigate the underlying mechanisms that may be responsible for diabetic microangiopathy in the inner ear, we studied the expression of VEGF, iNOS, and eNOS in the streptozotocin (STZ)-induced diabetic rat cochlea. MATERIALS AND METHODS The immunofluorescence studies were performed by using FITC-labelled specific antibodies to VEGF, iNOS, and eNOS on paraffin sections of the cochlea. The expression levels of VEGF, iNOS, and eNOS were quantified by means of Western blot analysis of cochlea protein extracts. Evans blue (EB) was used to investigate blood-labyrinth barrier (BLB) permeability in the cochlea. RESULTS Increased cochlear expression of VEGF, iNOS, and eNOS was detected in the diabetic rat. Furthermore, increased permeability of BLB was evidenced by increased cochlear EB extravasation in the diabetic rat.
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Gentamicin Increases Nitric Oxide Production and Induces Hearing Loss in Guinea Pigs. Laryngoscope 2008; 118:1438-42. [DOI: 10.1097/mlg.0b013e3181739bd9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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