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Moatti A, Silkstone D, Martin T, Abbey K, Hutson KA, Fitzpatrick DC, Zdanski CJ, Cheng AG, Ligler FS, Greenbaum A. Assessment of drug permeability through an ex vivo porcine round window membrane model. iScience 2023; 26:106789. [PMID: 37213232 PMCID: PMC10197016 DOI: 10.1016/j.isci.2023.106789] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 03/16/2023] [Accepted: 04/26/2023] [Indexed: 05/23/2023] Open
Abstract
Delivery of pharmaceutical therapeutics to the inner ear to treat and prevent hearing loss is challenging. Systemic delivery is not effective as only a small fraction of the therapeutic agent reaches the inner ear. Invasive surgeries to inject through the round window membrane (RWM) or cochleostomy may cause damage to the inner ear. An alternative approach is to administer drugs into the middle ear using an intratympanic injection, with the drugs primarily passing through the RWM to the inner ear. However, the RWM is a barrier, only permeable to a small number of molecules. To study and enhance the RWM permeability, we developed an ex vivo porcine RWM model, similar in structure and thickness to the human RWM. The model is viable for days, and drug passage can be measured at multiple time points. This model provides a straightforward approach to developing effective and non-invasive delivery methods to the inner ear.
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Affiliation(s)
- Adele Moatti
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC 27606, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27606, USA
| | - Dylan Silkstone
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC 27606, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27606, USA
| | - Taylor Martin
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27606, USA
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA
| | - Keith Abbey
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC 27606, USA
| | - Kendall A Hutson
- Department of Otolaryngology- Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Douglas C Fitzpatrick
- Department of Otolaryngology- Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Carlton J Zdanski
- Department of Otolaryngology- Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alan G Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, CA 94305, USA
| | - Frances S Ligler
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Alon Greenbaum
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC 27606, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27606, USA
- Corresponding author
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Lele P, Patel R. Intra-Tympanic Dexamethasone Therapy via Grommet Insertion for Improved Auditory Outcome in Sudden Sensorineural Hearing Loss. Indian J Otolaryngol Head Neck Surg 2023; 75:357-362. [PMID: 37206783 PMCID: PMC10188755 DOI: 10.1007/s12070-022-03464-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 12/30/2022] [Indexed: 01/15/2023] Open
Abstract
Idiopathic sudden-sensorineural hearing loss (ISSHL) is an emergent otological condition needing prompt treatment for better recovery. In our study we aimed to determine the efficacy of intra-tympanic dexamethasone therapy after inserting a grommet in postero-inferior quadrant of the tympanic membrane for dexamethasone instillation. This is a prospective cohort study of 31 patients of ISSHL, in whom grommet was inserted and dexamethasone drops were instilled for 5 days. Several factors such as time of initiation of therapy, age of patient was considered, and inferences were drawn. Auditory outcomes were divided into low, mid and high frequency and the results were tabulated. Paired t tested was applied for all frequencies for both pre-test and post-test. P-value was (< 0.05) in all the three ranges of frequencies. Also, statistical significance was found between early treatment from onset of disease and auditory outcome. The earlier the therapy was initiated, better were the results.
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Affiliation(s)
- Pushkar Lele
- Lele ENT Hospital and Research Centre, Kulkarni Garden, Sharanpur Road, Nashik, Maharashtra 422002 India
| | - Rushika Patel
- Lele ENT Hospital and Research Centre, Kulkarni Garden, Sharanpur Road, Nashik, Maharashtra 422002 India
- Dr Vasantrao Pawar Medical College, Hospital and Research Centre, Adgaon, Nashik, Maharashtra 422001 India
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3
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Chang WT, Zee B, Lee HS, Tong MC. Dexamethasone eardrop with grommet placement vs intratympanic steroid injection for sudden sensorineural hearing loss: A randomized prospective clinical trial. Am J Otolaryngol 2020; 41:102515. [PMID: 32487334 DOI: 10.1016/j.amjoto.2020.102515] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/18/2020] [Accepted: 04/19/2020] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The purpose of this study was to compare different means of intratympanic steroid delivery in the treatment of idiopathic sudden sensorineural hearing loss. DESIGN Prospective, multicentered, randomized controlled trial. SETTING AND PARTICIPANTS Fifty-six patients who fulfilled the inclusion criteria for idiopathic sudden sensorineural hearing loss who failed or were contraindicated for oral steroids were included in this study. Patients were randomly divided into 2 groups according to delivery methods: group A received 4 sections of intratympanic dexamethasone injection and group B received grommet placement with dexamethasone delivery followed by 3 sections of dexamethasone ear drop application. Self-administered paper-based questionnaires were filled out to measure subjective pain scores, vertigo, anxiety, and overall satisfaction immediately after each procedure. Hearing threshold was measured with pure tone audiogram in the follow-up. RESULTS There was no statistical significance detected in hearing threshold improvement between both groups (P = 0.30). Grommet placement followed by dexamethasone eardrop application demonstrated a significant difference in shorter waiting time (24 min in grommet group vs 52 min in injection group; P < 0.01); and better overall satisfaction (1.6 in grommet group vs 2.5 in injection group; P < 0.05). CONCLUSIONS Grommet placement followed by dexamethasone eardrop application is a good alternative for a patient indicated for intratympanic steroid, with less administrative cost, shorter waiting time, and more satisfaction.
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Salmito MC, E Maia FCZ, Gretes ME, Venosa A, Ganança FF, Ganança MM, Mezzalira R, Bittar RSM, Gasperin AC, Pires APBDÁ, Ramos BF, Bertoldo C, Ferreira C, Real D, Guimarães HA, Oiticica J, Lavinsky J, Lopes KC, Duarte JA, Morganti LOG, Santos LMAD, Joffily L, Lavinsky L, Santos MADO, Mano PM, Araújo PIMPD, Mangabeira Albernaz PL, Cal R, Dorigueto RS, Guimarães RDCC, Carvalho RCBD. Neurotology: definitions and evidence-based therapies - Results of the I Brazilian Forum of Neurotology. Braz J Otorhinolaryngol 2020; 86:139-148. [PMID: 31902583 PMCID: PMC9422724 DOI: 10.1016/j.bjorl.2019.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 11/06/2019] [Indexed: 11/27/2022] Open
Abstract
INTRODUCTION Neurotology is a rapidly expanding field of knowledge. The study of the vestibular system has advanced so much that even basic definitions, such as the meaning of vestibular symptoms, have only recently been standardized. OBJECTIVE To present a review of the main subjects of neurotology, including concepts, diagnosis and treatment of Neurotology, defining current scientific evidence to facilitate decision-making and to point out the most evidence-lacking areas to stimulate further new research. METHODS This text is the result of the I Brazilian Forum of Neurotology, which brought together the foremost Brazilian researchers in this area for a literature review. In all, there will be three review papers to be published. This first review will address definitions and therapies, the second one will address diagnostic tools, and the third will define the main diseases diagnoses. Each author performed a bibliographic search in the LILACS, SciELO, PubMed and MEDLINE databases on a given subject. The text was then submitted to the other Forum participants for a period of 30 days for analysis. A special chapter, on the definition of vestibular symptoms, was translated by an official translation service, and equally submitted to the other stages of the process. There was then a in-person meeting in which all the texts were orally presented, and there was a discussion among the participants to define a consensual text for each chapter. The consensual texts were then submitted to a final review by four professors of neurotology disciplines from three Brazilian universities and finally concluded. Based on the full text, available on the website of the Brazilian Association of Otorhinolaryngology and Cervical-Facial Surgery, this summary version was written as a review article. RESULT The text presents the official translation into Portuguese of the definition of vestibular symptoms proposed by the Bárány Society and brings together the main scientific evidence for each of the main existing therapies for neurotological diseases. CONCLUSION This text rationally grouped the main topics of knowledge regarding the definitions and therapies of Neurotology, allowing the reader a broad view of the approach of neurotological patients based on scientific evidence and national experience, which should assist them in clinical decision-making, and show the most evidence-lacking topics to stimulate further study.
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Affiliation(s)
- Márcio Cavalcante Salmito
- Universidade Federal de São Paulo (Unifesp), Escola Paulista de Medicina, Departamento de Otorrinolaringologia e Cirurgia Cérvico-Facial, Disciplina de Otologia e Otoneurologia, São Paulo, SP, Brazil.
| | | | - Mário Edvin Gretes
- Pontifícia Universidade Católica de Campinas (PUC-Campinas), Faculdade de Medicina, SP, Brazil
| | | | - Fernando Freitas Ganança
- Universidade Federal de São Paulo (Unifesp), Escola Paulista de Medicina, Departamento de Otorrinolaringologia e Cirurgia Cérvico-Facial, Disciplina de Otologia e Otoneurologia, São Paulo, SP, Brazil
| | - Maurício Malavasi Ganança
- Universidade Federal de São Paulo (Unifesp), Escola Paulista de Medicina, Departamento de Otorrinolaringologia e Cirurgia Cérvico-Facial, Disciplina de Otologia e Otoneurologia, São Paulo, SP, Brazil
| | - Raquel Mezzalira
- Universidade de Campinas (Unicamp), Disciplina de Otorrinolaringologia Cabeça e Pescoço, Campinas, SP, Brazil
| | - Roseli Saraiva Moreira Bittar
- Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), Setor de Otoneurologia, São Paulo, SP, Brazil
| | | | | | | | - César Bertoldo
- Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), Setor de Otoneurologia, São Paulo, SP, Brazil
| | - Cícero Ferreira
- Universidade Federal de São Paulo (Unifesp), Escola Paulista de Medicina, Departamento de Otorrinolaringologia e Cirurgia Cérvico-Facial, Disciplina de Otologia e Otoneurologia, São Paulo, SP, Brazil
| | - Danilo Real
- Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), Setor de Otoneurologia, São Paulo, SP, Brazil
| | | | - Jeanne Oiticica
- Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), Setor de Otoneurologia, São Paulo, SP, Brazil
| | - Joel Lavinsky
- Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Santa Casa de Porto Alegre, Porto Alegre, RS, Brazil
| | | | - Juliana Antoniolli Duarte
- Universidade Federal de São Paulo (Unifesp), Escola Paulista de Medicina, Departamento de Otorrinolaringologia e Cirurgia Cérvico-Facial, Disciplina de Otologia e Otoneurologia, São Paulo, SP, Brazil
| | - Lígia Oliveira Gonçalves Morganti
- Universidade Federal de Minas Gerais (UFMG), Faculdade de Medicina, Departamento de Otorrinolaringologia, Belo Horizonte, MG, Brazil
| | | | - Lúcia Joffily
- Hospital Universitário Gaffrée e Guinle, Universidade Federal do Estado do Rio de Janeiro (Unirio), Rio de Janeiro, RJ, Brazil
| | - Luíz Lavinsky
- Universidade Federal do Rio Grande do Sul (UFRGS), Faculdade de Medicina, Disciplina de Otorrinolaringologia, Porto Alegre, RS, Brazil
| | - Mônica Alcantara de Oliveira Santos
- Irmandade da Santa Casa de Misericórdia de São Paulo, Faculdade de Ciências Médicas, Departamento de Otorrinolaringologia, São Paulo, SP, Brazil; Instituto de Assistência Médica ao Servidor Público Estadual de São Paulo, São Paulo, SP, Brazil
| | - Patrícia Mauro Mano
- Hospital Federal dos Servidores do Rio de Janeiro, Departamento de Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Rio de Janeiro, RJ, Brazil
| | | | | | - Renato Cal
- Universidade Federal do Pará (UFPa), Faculdade de Medicina, Belém, PA, Brazil
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Sarna B, Abouzari M, Lin HW, Djalilian HR. A hypothetical proposal for association between migraine and Meniere's disease. Med Hypotheses 2019; 134:109430. [PMID: 31629154 DOI: 10.1016/j.mehy.2019.109430] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/01/2019] [Accepted: 10/10/2019] [Indexed: 12/15/2022]
Abstract
Meniere's disease (MD) is a chronic condition affecting the inner ear whose precise etiology is currently unknown. We propose the hypothesis that MD is a migraine-related phenomenon which may have implications for future treatment options for both diseases. The association between MD and migraine is both an epidemiological and a mechanistic one, with up to 51% of individuals with MD experiencing migraine compared to 12% in the general population. The presence of endolymphatic hydrops in those with MD may be the factor that unites the two conditions, as hydropic inner ears have an impaired ability to maintain homeostasis. Migraine headaches are theorized to cause aura and symptoms via spreading cortical depression that ultimately results in substance P release, alterations in blood flow, and neurogenic inflammation. Chronically hydropic inner ears are less able to auto-regulate against the changes induced by active migraine attacks and may ultimately manifest as MD. This same vulnerability to derangements in homeostasis may also explain the common triggering factors of both MD attacks and migraine headaches, including stress, weather, and diet. Similarly, it may explain the efficacy of common treatments for both diseases: current migraine treatments such as anti-hypertensives and anti-convulsants have shown promise in managing MD. Though the etiology of both MD and migraine is likely multifactorial, further exploration of the association between the two conditions may illuminate how to best manage them in the future. MD is likely a manifestation of cochleovestibular migraine, which occurs as a result of migraine related changes in both the cochlea and vestibule.
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Affiliation(s)
- Brooke Sarna
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, USA
| | - Mehdi Abouzari
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, USA; Division of Pediatric Otolaryngology, Children's Hospital of Orange County, Orange, USA
| | - Harrison W Lin
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, USA
| | - Hamid R Djalilian
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, USA; Department of Biomedical Engineering, University of California, Irvine, USA.
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6
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solak I, Arslan A, Kutlu R, Kozanhan B, Neşelioğlu S, Erel Ö, Çetinkaya ÇD, Eryılmaz MA. İdiopatik ani işitme kaybı olan hastaların tiyol/disülfit homeostazisi üzerine hiperbarik oksijen tedavisinin etkisi. FAMILY PRACTICE AND PALLIATIVE CARE 2018. [DOI: 10.22391/fppc.470360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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7
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Tillinger JA, Gupta C, Ila K, Ahmed J, Mittal J, Van De Water TR, Eshraghi AA. l-N-acetylcysteine protects outer hair cells against TNFα initiated ototoxicity in vitro. Acta Otolaryngol 2018. [PMID: 29513056 DOI: 10.1080/00016489.2018.1440086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The present study is aimed at determining the efficacy and exploring the mechanisms by which l-N-acetylcysteine (l-NAC) provides protection against tumor necrosis factor-alpha (TNFα)-induced oxidative stress damage and hair cell loss in 3-day-old rat organ of Corti (OC) explants. Previous work has demonstrated a high level of oxidative stress in TNFα-challenged OC explants. TNFα can potentially play a significant role in hair cell loss following an insult to the inner ear. l-NAC has shown to provide effective protection against noise-induced hearing loss in laboratory animals but mechanisms of this otoprotective effect are not well-defined. DESIGN Rat OC explants were exposed to either: (1) saline control (N = 12); (2) TNFα (2 μg/ml, N = 12); (3) TNFα+l-NAC (5 mM, N = 12); (4) TNFα+l-NAC (10 mM, N = 12); or (5) l-NAC (10 mM, N = 12). Outer hair cell (OHC) density, levels of reactive oxygen species (ROS), lipid peroxidation of cell membranes, gluthathione activity, and mitochondrial viability were assayed. RESULTS l-NAC (5 and 10 mM) provided protection for OHCs from ototoxic level of TNFα in OC explants. Groups treated with TNFα+l-NAC (5 mM) showed a highly significant reduction of both ROS (p < 0.01) and 4-hydroxy-2-nonenal immunostaining (p < 0.001) compared to TNFα-challenged explants. Total glutathione levels were low in TNFα-challenged explants compared to control and TNFα+l-NAC (5 mM) treated explants (p < 0.001). CONCLUSIONS l-NAC is a promising treatment for protecting auditory HCs from TNFα-induced oxidative stress and subsequent loss via programmed cell death.
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Affiliation(s)
- Joshua A. Tillinger
- Department of Otolaryngology, Hearing Research Laboratory, Miller School of Medicine University of Miami, Miami, FL, USA
| | - Chhavi Gupta
- Department of Otolaryngology, Hearing Research Laboratory, Miller School of Medicine University of Miami, Miami, FL, USA
| | - Kadri Ila
- Department of Otolaryngology, Hearing Research Laboratory, Miller School of Medicine University of Miami, Miami, FL, USA
| | - Jamal Ahmed
- Department of Otolaryngology, Hearing Research Laboratory, Miller School of Medicine University of Miami, Miami, FL, USA
| | - Jeenu Mittal
- Department of Otolaryngology, Hearing Research Laboratory, Miller School of Medicine University of Miami, Miami, FL, USA
| | - Thomas R. Van De Water
- Department of Otolaryngology, Hearing Research Laboratory, Miller School of Medicine University of Miami, Miami, FL, USA
| | - Adrien A. Eshraghi
- Department of Otolaryngology, Hearing Research Laboratory, Miller School of Medicine University of Miami, Miami, FL, USA
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Kasica N, Podlasz P, Sundvik M, Tamas A, Reglodi D, Kaleczyc J. Protective Effects of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Against Oxidative Stress in Zebrafish Hair Cells. Neurotox Res 2016; 30:633-647. [PMID: 27557978 PMCID: PMC5047952 DOI: 10.1007/s12640-016-9659-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/26/2016] [Accepted: 08/09/2016] [Indexed: 12/30/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide, with known antiapoptotic functions. Our previous in vitro study has demonstrated the ameliorative role of PACAP-38 in chicken hair cells under oxidative stress conditions, but its effects on living hair cells is now yet known. Therefore, the aim of the present study was to investigate in vivo the protective role of PACAP-38 in hair cells found in zebrafish (Danio rerio) sense organs-neuromasts. To induce oxidative stress the 5-day postfertilization (dpf) zebrafish larvae were exposed to 1.5 mM H2O2 for 15 min or 1 h. This resulted in an increase in caspase-3 and p-38 MAPK level in the hair cells as well as in an impairment of the larvae basic behavior. To investigate the ameliorative role of PACAP-38, the larvae were incubated with a mixture of 1.5 mM H2O2 and 100 nM PACAP-38 following 1 h preincubation with 100 nM PACAP-38 only. PACAP-38 abilities to prevent hair cells from apoptosis were investigated. Whole-mount immunohistochemistry and confocal microscopy analyses revealed that PACAP-38 treatment decreased the cleaved caspase-3 level in the hair cells, but had no influence on p-38 MAPK. The analyses of basic locomotor activity supported the protective role of PACAP-38 by demonstrating the improvement of the fish behavior after PACAP-38 treatment. In summary, our in vivo findings demonstrate that PACAP-38 protects zebrafish hair cells from oxidative stress by attenuating oxidative stress-induced apoptosis.
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Affiliation(s)
- Natalia Kasica
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, box 105J, 10-719, Olsztyn, Poland.
| | - Piotr Podlasz
- Department of Pathophysiology, Forensic Veterinary and Administration, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland
| | - Maria Sundvik
- Department of Anatomy, Neuroscience Center, University of Helsinki, Haartmaninkatu 8 (Biomedicum Helsinki), 00290, Helsinki, Finland
| | - Andrea Tamas
- Department of Anatomy, University of Pecs, Szigeti 12, 7624, Pecs, Hungary
| | - Dora Reglodi
- Department of Anatomy, University of Pecs, Szigeti 12, 7624, Pecs, Hungary
| | - Jerzy Kaleczyc
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, box 105J, 10-719, Olsztyn, Poland
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Inhibition of p38 mitogen-activated protein kinase ameliorates radiation-induced ototoxicity in zebrafish and cochlea-derived cell lines. Neurotoxicology 2013; 40:111-22. [PMID: 24374476 DOI: 10.1016/j.neuro.2013.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 12/04/2013] [Accepted: 12/10/2013] [Indexed: 11/21/2022]
Abstract
Radiation is a widely used treatment for head and neck cancers, and one of its most severe side effects is ototoxicity. Radiation-induced ototoxicity has been demonstrated to be linked to the increased production of ROS and MAPK. We intended to investigate the effect of p38 inhibition on radiation-induced ototoxicity in cochlea-derived HEI-OC1 cells and in a zebrafish model. The otoprotective effect of p38 inhibition against radiation was tested in vitro in the organ of Corti-derived cell line, HEI-OC1, and in vivo in a zebrafish model. Radiation-induced apoptosis, mitochondrial dysfunction, and an increase of intracellular NO generation were demonstrated in HEI-OC1 cells. The p38-specific inhibitor, SB203580, ameliorated radiation-induced apoptosis and mitochondrial injury in HEI-OC1 cells. p38 inhibition reduced radiation-induced activation of JNK, p38, cytochrome c, and cleavage of caspase-3 and PARP in HEI-OC1 cells. Scanning electron micrography showed that SB203580 prevented radiation-induced destruction of kinocilium and stereocilia in zebrafish neuromasts. The results of this study suggest that p38 plays an important role in mediating radiation-induced ototoxicity and inhibition of p38 could be a plausible option for preventing radiation ototoxicity.
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Key Words
- Apoptosis
- DMEM,
- DMSO,
- Dulbecco's modified Eagle's medium
- ERK,
- FBS,
- FITC,
- HNSCC,
- IHC,
- Inner hair cell
- JNK,
- MAPK,
- MMP,
- NO,
- PARP,
- PBS,
- PI,
- ROS,
- SB203580
- SEM,
- SNHL,
- TUNEL,
- c-Jun N-terminal kinase
- days post-fertilization
- dimethyl sulfoxide
- dpf,
- extracellular signal-regulated kinases
- fetal bovine serum
- fluorescein isothiocyanate
- head and neck squamous cell carcinoma
- hearing preservation
- mitochondrial membrane potential
- mitogen-activated protein kinase
- nitric oxide
- p38
- p38, p38
- phosphate buffered saline
- poly ADP ribose polymerase
- propidium iodide
- radiation
- reactive oxygen species
- scanning electron microscopy
- sensorineural hearing loss
- terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling
- zebrafish
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Tan PX, Du SS, Ren C, Yao QW, Yuan YW. Radiation-induced Cochlea Hair Cell Death: Mechanisms and Protection. Asian Pac J Cancer Prev 2013; 14:5631-5. [DOI: 10.7314/apjcp.2013.14.10.5631] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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11
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Abstract
CONCLUSION Brain-derived neurotrophic factor (BDNF) can prevent auditory brainstem response (ABR) threshold shift changes caused by Pseudomonas aeruginosa exotoxin A (PaExoA). OBJECTIVE Peptides of the neurotrophin family are known to prevent neuronal death during embryonic development by interacting with specific membrane receptors. The purpose of this study was to investigate whether a single dose of BDNF is an effective protectant against toxic effects of PaExoA-induced ABR threshold shifts. MATERIALS AND METHODS Eight groups of Sprague-Dawley rats were used. There were five control groups (n = 20) as follows. Group A (n = 4) received NaCl solution; group B (n = 3) received 4 µg BDNF; group C (n = 4) received 1 μg/20 μl PaExoA; group D (n = 4) received 2 μg/20 μl PaExoA; group E (n = 5) received 10 µg/20 µl PaExoA injected into the round window niche. Three treatment groups (n = 13) received a single dose of PaExoA and 4 µg of BDNF simultaneously. Group 1 (n = 3) received 1 μg/20 μl PaExoA + 4 µg of BDNF; group 2 (n = 5) received 2 μg/20 μl PaExoA + 4 µg BDNF; group 3 (n = 5) received 10 μg/20 μl PaExoA + 4 µg BDNF. ABR was used to measure efficacy by analyzing threshold shifts before and after injections. RESULTS A single dose of BDNF prevented changes in ABR thresholds following exposure to increasing concentrations of PaExoA injected into the middle ear.
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Affiliation(s)
- Adnan Lidian
- Department of Oto-Rhino-Laryngology and Head & Neck Surgery, University Hospital (Akademiska sjukhuset), Uppsala, Sweden.
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Spear SA, Schwartz SR. Intratympanic Steroids for Sudden Sensorineural Hearing Loss. Otolaryngol Head Neck Surg 2011; 145:534-43. [DOI: 10.1177/0194599811419466] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective. To determine the evidence for efficacy of intratympanic (IT) steroid treatment for the management of idiopathic sudden sensorineural hearing loss through a systematic review of the existing literature. Data Sources. Online databases consisting of PubMed, Medline, OVID, Google Scholar, Cochrane Review, and collected additional publications cited in bibliographies. Review Methods. Literature search by both authors with structured criteria to select studies evaluated for systematic review. Results. The authors identified 176 articles, of which 32 represented studies of initial or salvage intratympanic steroid injections for sudden hearing loss that included 6 randomized trials and only 2 randomized controlled trials. Despite the paucity of well-executed trials, the vast majority of studies of intratympanic steroids for salvage treatment in all tiers demonstrated a benefit of intratympanic steroid therapy. A limited meta-analysis of the higher quality studies revealed a mean difference in improvement of 13.3 dB (95% confidence interval [CI], 7.7-18.9; P < .0001). Although statistically significant, it is still unclear if this difference is clinically significant. Initial intratympanic therapy was equivalent to standard therapy in the existing literature of all qualities. Conclusion. Intratympanic steroid treatment as primary treatment for sudden sensorineural hearing loss appears equivalent to treatment with high-dose oral prednisone therapy. As salvage therapy, intratympanic steroids offer the potential for some degree of additional hearing recovery, although it remains uncertain if this improvement is clinically significant and what percentage of patients is likely to show benefit.
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Affiliation(s)
- Samuel A. Spear
- Otolaryngology/Head & Neck Surgery, 48th Medical Group, RAF Lakenheath, UK
| | - Seth R. Schwartz
- Department of Otolaryngology/Head & Neck Surgery, Virginia Mason Medical Center, Seattle, Washington, USA
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Wang Z, Liu Y, Han N, Chen X, Yu W, Zhang W, Zou F. Profiles of oxidative stress-related microRNA and mRNA expression in auditory cells. Brain Res 2010; 1346:14-25. [DOI: 10.1016/j.brainres.2010.05.059] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 05/18/2010] [Accepted: 05/20/2010] [Indexed: 11/30/2022]
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14
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Permanent and transient effects of locally delivered n-acetyl cysteine in a guinea pig model of cochlear implantation. Hear Res 2010; 259:24-30. [DOI: 10.1016/j.heares.2009.08.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 08/28/2009] [Accepted: 08/29/2009] [Indexed: 12/14/2022]
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16
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Racz B, Horvath G, Reglodi D, Gasz B, Kiss P, Gallyas F, Sumegi B, Toth G, Nemeth A, Lubics A, Tamas A. PACAP ameliorates oxidative stress in the chicken inner ear: an in vitro study. ACTA ACUST UNITED AC 2009; 160:91-8. [PMID: 19969027 DOI: 10.1016/j.regpep.2009.12.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 11/09/2009] [Accepted: 12/02/2009] [Indexed: 11/30/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a pleiotropic and multifunctional neuropeptide. Numerous studies prove that PACAP has neuroprotective effects in diverse neuronal systems in vitro and in vivo. The involvement of PACAP in visual and olfactory sensory processing has also been documented, but little is known about its effects in the auditory system. The presence of PACAP and its receptor, the specific PAC1 receptor, has been shown in the cochlea and in brain structures involved in auditory pathways. The aim of the present study was to investigate whether PACAP is protective in cochlear oxidative stress-induced cell death, which is known to play a role in several ototoxic insults. Chicken cochlear cells were exposed to 1mM H(2)O(2), which resulted in a marked reduction of cell viability and a parallel increase of apoptotic and necrotic cells assessed by MTT test, annexin V/propidium iodide flow cytometry and JC-1 apoptosis assay. Co-incubation with 100nM PACAP increased cell viability and reduced the percentage of apoptotic cells. Furthermore, oxidative stress increased the activation of caspase-3, while simultaneous PACAP treatment reduced it. In summary, our present results demonstrate that PACAP effectively protects cochlear cells against oxidative stress-induced apoptotic cell death.
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Affiliation(s)
- Boglarka Racz
- Department of Biochemistry and Medical Chemistry, University of Pecs, Hungary
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17
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Mikulec AA, Hartsock JJ, Salt AN. Permeability of the round window membrane is influenced by the composition of applied drug solutions and by common surgical procedures. Otol Neurotol 2009; 29:1020-6. [PMID: 18758387 DOI: 10.1097/mao.0b013e31818658ea] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Intratympanic drug delivery has become widely used in the clinic, but little is known regarding how clinically used drug preparations affect round window membrane (RWM) permeability or how much drug is actually delivered to the cochlea. This study evaluated the effect of clinically relevant carrier solutions and of suction near the RWM on the permeability properties of the RWM. METHODS RWM permeability was assessed by perfusion of the marker trimethylphenylammonium into the round window niche while monitoring entry into perilymph using trimethylphenylammonium-selective electrodes sealed into scala tympani. RESULTS High-osmolarity solution increased RWM permeability by a factor of 2 to 3, benzyl alcohol (a preservative used in some drug formulations) increased permeability by a factor of 3 to 5, and suctioning near the RWM increased permeability by a factor of 10 to 15. CONCLUSION Variations in available drug formulations can potentially alter RWM permeability properties and affect the amount of drug delivered to the inner ear. Drug solution osmolarity, benzyl alcohol content, and possible drying of the RWM during suctioning the middle ear can all have a substantial influence of the perilymph levels of drug achieved.
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Affiliation(s)
- Anthony A Mikulec
- Department of Otolaryngology, Saint Louis University School of Medicine, St. Louis, Missouri, USA.
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18
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Low WK, Tan MGK, Chua AWC, Sun L, Wang DY. 12th Yahya Cohen Memorial Lecture – The Cellular and Molecular Basis of Radiation-induced Sensori-neural Hearing Loss. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2009. [DOI: 10.47102/annals-acadmedsg.v38n1p91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Introduction: Sensori-neural hearing loss (SNHL) is a frequent complication of conventional radiotherapy for head and neck tumours, especially nasopharyngeal carcinoma. To manage radiation-induced ototoxicity appropriately, an understanding of the cellular and molecular basis of this complication is necessary.
Materials and Methods: A medline search of relevant literature was done, focusing on the radiation-induced cellular and molecular processes that lead to hair cell death in the cochlea.
Results:Radiation-induced SNHL occurs in the cochlea, with the retro-cochlear pathways remaining functionally intact. By simulating radiotherapy regimes used clinically, radiation-induced cochlear cell degeneration in the absence of damage to the supporting structures and blood vessels has been demonstrated in animals. This could be due to apoptotic cochlear cell death, which has been shown to be associated with p53 upregulation and intra-cellular reactive oxygen species (ROS) generation. Oxidative stress may initiate the upstream processes that lead to apoptosis and other cell death mechanisms.
Conclusions: A model of radiation-induced SNHL based on a dose and ROS-dependant cochlear cell apoptosis, is proposed. This model supports the feasibility of cochlear implantation, should one be clinically indicated. It can explain clinical observations such as radiation-induced SNHL being dose-dependent and affects the high frequencies more than the lower frequencies. It also opens up the possibility of preventive strategies targeted at different stages of the apoptotic process. Antioxidants look promising as effective agents to prevent radiation-induced ototoxicity; they target upstream processes leading to different cell death mechanisms that may co-exist in the population of damaged cells.
Radiation-induced sensori-neural hearing loss (SNHL) has long been recognised as a complication of radiotherapy (RT) for head and neck tumours, if the auditory pathways had been included in the radiation fields. In Singapore, nasopharyngeal carcinoma (NPC) is common and the prevalence of SNHL after radiotherapy for NPC has been reported to be as high as 24%. Radiation-induced ototoxicity is therefore an important clinical problem in Singapore. To be able to manage radiation-induced ototoxicity appropriately, a good understanding of the cellular and molecular basis of this complication is necessary.
Key words: Apoptosis, Deafness, Hair cell, Ototoxicity, Radiotherapy
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Affiliation(s)
| | | | | | - Li Sun
- Singapore General Hospital, Singapore
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Hendricks JL, Chikar JA, Crumling MA, Raphael Y, Martin DC. Localized cell and drug delivery for auditory prostheses. Hear Res 2008; 242:117-31. [PMID: 18573323 DOI: 10.1016/j.heares.2008.06.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 05/09/2008] [Accepted: 06/02/2008] [Indexed: 12/20/2022]
Abstract
Localized cell and drug delivery to the cochlea and central auditory pathway can improve the safety and performance of implanted auditory prostheses (APs). While generally successful, these devices have a number of limitations and adverse effects including limited tonal and dynamic ranges, channel interactions, unwanted stimulation of non-auditory nerves, immune rejection, and infections including meningitis. Many of these limitations are associated with the tissue reactions to implanted auditory prosthetic devices and the gradual degeneration of the auditory system following deafness. Strategies to reduce the insertion trauma, degeneration of target neurons, fibrous and bony tissue encapsulation, and immune activation can improve the viability of tissue required for AP function as well as improve the resolution of stimulation for reduced channel interaction and improved place-pitch and level discrimination. Many pharmaceutical compounds have been identified that promote the viability of auditory tissue and prevent inflammation and infection. Cell delivery and gene therapy have provided promising results for treating hearing loss and reversing degeneration. Currently, many clinical and experimental methods can produce extremely localized and sustained drug delivery to address AP limitations. These methods provide better control over drug concentrations while eliminating the adverse effects of systemic delivery. Many of these drug delivery techniques can be integrated into modern auditory prosthetic devices to optimize the tissue response to the implanted device and reduce the risk of infection or rejection. Together, these methods and pharmaceutical agents can be used to optimize the tissue-device interface for improved AP safety and effectiveness.
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Affiliation(s)
- Jeffrey L Hendricks
- Department of Biomedical Engineering, The University of Michigan, 1107 Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109-2099, USA.
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20
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Low WK, Sun L, Tan MG, Chua AW, Wang DY. L-N-Acetylcysteine protects against radiation-induced apoptosis in a cochlear cell line. Acta Otolaryngol 2008; 128:440-5. [PMID: 18368580 DOI: 10.1080/00016480701762490] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
CONCLUSION L-N-Acetylcysteine (L-NAC) significantly reduced reactive oxygen species (ROS) generation and cochlear cell apoptosis after irradiation. The safe and effective use of L-NAC in reducing radiation-induced sensorineural hearing loss (SNHL) should be verified by further in vivo studies. OBJECTIVES Radiation-induced SNHL is a common complication after radiotherapy of head and neck tumours. There is growing evidence to suggest that ROS play an important role in apoptotic cochlear cell death from ototoxicity, resulting in SNHL. The aim of this study was to evaluate the effectiveness of L-NAC, an antioxidant, on radiation-induced apoptosis in cochlear cells. MATERIALS AND METHODS The OC-k3 cochlear cell line was studied after 0 and 20 Gy of gamma-irradiation. Cell viability assay was performed using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide. Flow cytometry and TUNEL assay were done with and without the addition of 10 mmol/L of L-NAC. Intracellular generation of ROS was detected by 2',7'-dichlorofluorescein diacetate, with comparisons made using fluorescence intensity. RESULTS L-NAC increased the viability of cells after irradiation. Generation of ROS was demonstrated at 1 h post-irradiation and was significantly reduced by L-NAC (p<0.0001). Flow cytometry and TUNEL assay showed cell apoptosis at 72 h post-irradiation, which was diminished by the addition of L-NAC.
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21
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Cooper LB, Chan DK, Roediger FC, Shaffer BR, Fraser JF, Musatov S, Selesnick SH, Kaplitt MG. AAV-mediated delivery of the caspase inhibitor XIAP protects against cisplatin ototoxicity. Otol Neurotol 2008; 27:484-90. [PMID: 16791039 DOI: 10.1097/01.mao.0000202647.19355.6a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Delivery of the gene encoding X-linked inhibitor of apoptosis (XIAP) using an adeno-associated viral (AAV) vector can protect against cisplatin-mediated ototoxicity. BACKGROUND Cisplatin is a widely used chemotherapeutic agent with significant ototoxic side effects. One possible mechanism of toxicity is apoptotic death of many cochlear cell types. Acute treatment with inhibitors of caspases- enzymes critical for apoptosis- has been shown to prevent hearing loss in vivo, but is too short-acting for therapeutic use. Gene therapy provides a specific and chronic means of delivering potential therapeutic gents. Introducing an anti-apoptotic gene into the cochlea could provide long-term prophylaxis against the ototoxic effects of cisplatin. METHOD Two groups of rats were treated with unilateral injection into the round window of AAV harboring a gene encoding either XIAP or green fluorescent protein (GFP). After at least two months of gene expression, auditory-brainstem-response (ABR) threshold shifts and outer-hair-cell (OHC) number were measured in these two groups of animals after 72-hour treatment with cisplatin. RESULTS Consistent with previous reports, uninjected and AAV.GFP-injected ears displayed profound ABR threshold elevations and OHC loss after cisplatin treatment. Ears that had been injected with AAV encoding XIAP, however, were significantly protected from these effects: cisplatin-induced ABR-threshold shift and hair-cell loss were attenuated by as much as 78% and 45%, respectively, when compared with contralateral (untreated) ears. CONCLUSION XIAP delivery to the cochlea can protect against the audiometric changes and hair-cell loss associated with cisplatin ototoxicity. The efficacy, specificity, and duration of the protective effects make this a potentially attractive therapeutic paradigm.
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MESH Headings
- Animals
- Antineoplastic Agents/toxicity
- Apoptosis/drug effects
- Audiometry, Evoked Response
- Auditory Threshold/drug effects
- Caspase Inhibitors
- Cisplatin/toxicity
- Dependovirus
- Evoked Potentials, Auditory, Brain Stem/physiology
- Genetic Therapy/methods
- Genetic Vectors
- Green Fluorescent Proteins/administration & dosage
- Green Fluorescent Proteins/genetics
- Hair Cells, Auditory, Outer/drug effects
- Hair Cells, Auditory, Outer/pathology
- Hearing Loss, Sensorineural/chemically induced
- Hearing Loss, Sensorineural/prevention & control
- Male
- Microscopy, Fluorescence
- Multivariate Analysis
- Pilot Projects
- Random Allocation
- Rats
- Rats, Sprague-Dawley
- X-Linked Inhibitor of Apoptosis Protein/administration & dosage
- X-Linked Inhibitor of Apoptosis Protein/genetics
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Affiliation(s)
- Louis B Cooper
- Department of Neurological Surgery, Weill Medical College of Cornell University, New York, New York 10021, USA
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22
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In vitro permeability of round window membrane to transforming dexamethasone with delivery vehicles — a dosage estimation. Chin Med J (Engl) 2007. [DOI: 10.1097/00029330-200712020-00025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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23
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Chan DK, Lieberman DM, Musatov S, Goldfein JA, Selesnick SH, Kaplitt MG. Protection Against Cisplatin-Induced Ototoxicity by Adeno-Associated Virus-Mediated Delivery of the X-Linked Inhibitor of Apoptosis Protein Is Not Dependent on Caspase Inhibition. Otol Neurotol 2007; 28:417-25. [PMID: 17211286 DOI: 10.1097/01.mao.0000247826.28893.7a] [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: 01/14/2023]
Abstract
HYPOTHESIS Gene therapy with an adeno-associated viral (AAV) vector encoding the X-linked inhibitor of apoptosis protein (XIAP) in an animal model of cisplatin-induced ototoxicity can elucidate apoptotic pathways in the inner ear. BACKGROUND Cisplatin is limited clinically by ototoxicity associated with apoptosis in the inner ear. The relevant intracellular apoptotic pathways, however, are unknown. XIAP is an antiapoptotic protein that both inhibits caspases and reciprocally regulates the proapoptotic Smac/Omi proteins. AAV-mediated delivery of various XIAP mutants could distinguish between these antiapoptotic pathways in the ear and further the development of specific reagents for gene therapy- mediated prevention of cisplatin-induced ototoxicity. METHODS We administered unilaterally through the round-window AAV-harboring genes encoding wild-type dXIAP, yellow fluorescent protein, or either of two dXIAP point mutants-one deficient in caspase inhibition (dXIAP-d) and the other additionally deficient in the binding of Smac/Omi (dXIAP-t). All rats received a 3-day systemic course of cisplatin. Functional hearing loss was measured by shifts in auditory brainstem response (ABR) thresholds after cisplatin treatment, and hair-cell loss was assessed by whole-mount phalloidin staining of cochlear turns. RESULTS Uninjected ears universally displayed high-frequency-specific hair-cell loss and ABR threshold shifts upon cisplatin treatment. Although yellow fluorescent protein had no effect, ears injected with dXIAP exhibited 68% less ABR threshold shift at 32 kHz and 50% less basal-turn outer-hair-cell loss compared with contralateral untreated ears. This protection was maintained in ears injected with dXIAP-d but was abolished in those expressing dXIAP-t, which is incapable of blocking Smac/Omi. CONCLUSION Hair-cell apoptosis induced by cisplatin involves the Smac/Omi pathway. Thus, gene therapy with either wild-type dXIAP or Smac/Omi-selective dXIAP-d may be effective to protect against cisplatin-mediated ototoxicity.
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Affiliation(s)
- Dylan K Chan
- Weill Medical College, Cornell University, New York, New York 10021, USA
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Tiede LM, Rocha-Sanchez SM, Hallworth R, Nichols MG, Beisel K. Determination of hair cell metabolic state in isolated cochlear preparations by two-photon microscopy. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:021004. [PMID: 17477711 PMCID: PMC1992521 DOI: 10.1117/1.2714777] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Currently there is no accepted method to measure the metabolic status of the organ of Corti. Since metabolism and mitochondrial dysfunction are expected to play a role in many different hearing disorders, here for the first time we employ two-photon metabolic imaging to assess the metabolic status of the cochlea. When excited with ultrashort pulses of 740-nm light, both inner and outer hair cells in isolated murine cochlear preparations exhibited intrinsic fluorescence. This fluorescence is characterized and shown to be consistent with a mixture of oxidized flavoproteins (Fp) and reduced nicotinamide adenine dinucleotide (NADH). The location of the fluorescence within hair cells is also consistent with the different mitochondrial distributions in these cell types. Treatments with cyanide and mitochondrial uncouplers show that hair cells are metabolically active. Both NADH and Fp in inner hair cells gradually become completely oxidized within 50 min from the time of death of the animal. Outer hair cells show similar trends but are found to have greater variability. We show that it is possible to use two-photon metabolic imaging to assess metabolism in the mouse organ of Corti.
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Affiliation(s)
- Leann M Tiede
- Creighton University, Department of Biomedical Sciences, Omaha, Nebraska 68178, USA.
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Low WK, Tan MGK, Sun L, Chua AWC, Goh LK, Wang DY. Dose-dependant radiation-induced apoptosis in a cochlear cell-line. Apoptosis 2006; 11:2127-36. [PMID: 17051332 DOI: 10.1007/s10495-006-0285-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cisplatin and gentamycin are both ototoxic and they have been shown to induce cochlear cell apoptosis. Although radiation is also ototoxic, radiation-induced apoptosis in cochlear cells has not been studied. This study aimed to investigate the biophysical changes of dose-related radiation-induced cochlear cell apoptosis in an experimental model. Post gamma-irradiation apoptosis was demonstrated in the cochlear cell-line OC-k3 by flow cytometry and TUNEL assay. This was dose-dependant with enhanced apoptosis resulting after 20 than 5 Gy, and occurred predominantly at 72 h post-irradiation. Microarray analysis showed associated dose-dependant apoptotic gene regulation changes. Western blotting revealed p53 up-regulation of at 72 h and phosphorylation at 3, 24, 48 and 72 h after irradiation. Early activation of c-jun occurred at 3 h, but was not sustained with time. Associated dose-dependant intracellular generation of reactive oxygen species (ROS) was also demonstrated using 2', 7'-dichlorofluorescein diacetate. In conclusion, this study demonstrated a dose-dependant cochlear cell apoptosis and associated ROS generation after irradiation, with p53 possibly playing a key role. Based on this ROS-linked apoptotic model, anti-oxidants and anti-apoptotic factors could potentially be used to prevent radiation-induced sensori-neural hearing loss. As these medications can be delivered topically through the middle ear, their systematic side effects could therefore be minimized.
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Affiliation(s)
- Wong-Kein Low
- Department of Otolaryngology, Singapore General Hospital, Singapore, 169608, Singapore.
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Sendowski I, Abaamrane L, Raffin F, Cros A, Clarençon D. Therapeutic efficacy of intra-cochlear administration of methylprednisolone after acoustic trauma caused by gunshot noise in guinea pigs. Hear Res 2006; 221:119-27. [PMID: 17008037 DOI: 10.1016/j.heares.2006.08.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 08/03/2006] [Accepted: 08/07/2006] [Indexed: 12/20/2022]
Abstract
The therapeutic efficacy of cochlear infusion of methylprednisolone (MP) after an impulse noise trauma (170dB SPL peak) was evaluated in guinea pigs. The compound action potential threshold shifts were measured over a 14 days recovery period after the gunshot exposure. For each animal, one of the cochlea was perfused directly into the scala tympani with MP during 7 days via a mini-osmotic pump, whereas the other cochlea was not pump-implanted. The functional study of hearing was supplemented by histological analysis. Forty eight hours after the trauma, significant differences between auditory threshold shifts in the implanted and non-implanted ears were observed for frequencies above 8kHz. At day 7, the difference was significant for only one frequency and no difference was observed after 14 days recovery. Cochleograms showed that the hair cell losses were significantly lower in the MP treated ears. This work indicates that direct infusion of MP into perilymphatic space accelerates hearing recovery, reduces hair cell losses after impulse noise trauma but does not limit permanent threshold shifts.
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MESH Headings
- Action Potentials/drug effects
- Animals
- Cochlea/drug effects
- Firearms
- Guinea Pigs
- Hair Cells, Auditory, Inner/drug effects
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Outer/drug effects
- Hair Cells, Auditory, Outer/pathology
- Hearing Loss, Noise-Induced/drug therapy
- Hearing Loss, Noise-Induced/etiology
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Methylprednisolone/administration & dosage
- NF-kappa B/physiology
- Nitric Oxide/physiology
- Oxidative Stress/drug effects
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Affiliation(s)
- I Sendowski
- Centre de recherches du service de santé des armées (CRSSA), Département de radiobiologie, 24 avenue des Maquis du Grésivaudan, BP 87, 38702 La Tronche Cedex, France.
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Dallan I, Bruschini L, Nacci A, Bruschini P, Traino C, Rognini F, Fattori B. Transtympanic steroids as a salvage therapy in sudden hearing loss: preliminary results. ORL J Otorhinolaryngol Relat Spec 2006; 68:247-52. [PMID: 16679810 DOI: 10.1159/000093093] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2005] [Accepted: 07/15/2005] [Indexed: 11/19/2022]
Abstract
PURPOSE To understand the real efficacy of transtympanic steroid therapy for sudden sensorineural hearing loss (SSHL) in patients in whom traditional therapies have failed. PROCEDURES A prospective study was designed in order to evaluate hearing improvement in SSHL patients treated with transtympanic therapy. A solution of methyl-prednisolone (MP) and sodium bicarbonate was administered via a transtympanic injection to 8 patients. Hearing level was evaluated before therapy and at days 1, 7 and 30. RESULTS Hearing improvement was obtained in 75% of the patients. The patients in this category are usually considered untreatable. CONCLUSION Transtympanic steroid therapy is an efficacious solution for patients affected by SSHL in whom traditional therapies have failed. Further studies will be required to identify the most favourable dosage, route of administration and type of steroid. Transtympanic steroid application is safe, inexpensive, easy to perform and efficacious in cases of SSHL not responsive to traditional therapy.
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Affiliation(s)
- Iacopo Dallan
- Second ENT Unit, Pisa University Hospital, Pisa, Italy.
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29
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Holley MC. Keynote review: The auditory system, hearing loss and potential targets for drug development. Drug Discov Today 2005; 10:1269-82. [PMID: 16214671 DOI: 10.1016/s1359-6446(05)03595-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
There is a huge potential market for the treatment of hearing loss. Drugs are already available to ameliorate predictable, damaging effects of excessive noise and ototoxic drugs. The biggest challenge now is to develop drug-based treatments for regeneration of sensory cells following noise-induced and age-related hearing loss. This requires careful consideration of the physiological mechanisms of hearing loss and identification of key cellular and molecular targets. There are many molecular cues for the discovery of suitable drug targets and a full range of experimental resources are available for initial screening through to functional analysis in vivo. There is now an unparalleled opportunity for translational research.
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Affiliation(s)
- Matthew C Holley
- Department of Biomedical Sciences, Addison Building, Western Bank, Sheffield S10 2TN, UK.
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