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Kim J, Hemachandran S, Cheng AG, Ricci AJ. Identifying targets to prevent aminoglycoside ototoxicity. Mol Cell Neurosci 2022; 120:103722. [PMID: 35341941 PMCID: PMC9177639 DOI: 10.1016/j.mcn.2022.103722] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/14/2022] [Accepted: 03/19/2022] [Indexed: 12/21/2022] Open
Abstract
Aminoglycosides are potent antibiotics that are commonly prescribed worldwide. Their use carries significant risks of ototoxicity by directly causing inner ear hair cell degeneration. Despite their ototoxic side effects, there are currently no approved antidotes. Here we review recent advances in our understanding of aminoglycoside ototoxicity, mechanisms of drug transport, and promising sites for intervention to prevent ototoxicity.
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Affiliation(s)
- Jinkyung Kim
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sriram Hemachandran
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alan G Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Anthony J Ricci
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Fu X, Wan P, Li P, Wang J, Guo S, Zhang Y, An Y, Ye C, Liu Z, Gao J, Yang J, Fan J, Chai R. Mechanism and Prevention of Ototoxicity Induced by Aminoglycosides. Front Cell Neurosci 2021; 15:692762. [PMID: 34211374 PMCID: PMC8239227 DOI: 10.3389/fncel.2021.692762] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 05/20/2021] [Indexed: 02/02/2023] Open
Abstract
Aminoglycosides, a class of clinically important drugs, are widely used worldwide against gram-negative bacterial infections. However, there is growing evidence that aminoglycosides can cause hearing loss or balance problems. In this article, we mainly introduce the main mechanism of ototoxicity induced by aminoglycosides. Genetic analysis showed that the susceptibility of aminoglycosides was attributable to mutations in mtDNA, especially A1555G and C1494T mutations in 12S rRNA. In addition, the overexpression of NMDA receptors and the formation of free radicals also play an important role. Understanding the mechanism of ototoxicity induced by aminoglycosides is helpful to develop new therapeutic methods to protect hearing. In this article, the prevention methods of ototoxicity induced by aminoglycosides were introduced from the upstream and downstream aspects.
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Affiliation(s)
- Xiaolong Fu
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Peifeng Wan
- School of Life Science, Shandong University, Qingdao, China
| | - Peipei Li
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jinpeng Wang
- The Key Laboratory of Animal Resistant Biology of Shandong, College of Life Science, Shandong Normal University, Jinan, China
| | - Siwei Guo
- School of Life Science, Shandong University, Qingdao, China
| | - Yuan Zhang
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yachun An
- School of Life Science, Shandong University, Qingdao, China
| | - Chao Ye
- School of Life Science, Shandong University, Qingdao, China
| | - Ziyi Liu
- School of Life Science, Shandong University, Qingdao, China
| | - Jiangang Gao
- School of Life Science, Shandong University, Qingdao, China
| | - Jianming Yang
- Second Hospital of Anhui Medical University, Hefei, China
| | - Jiangang Fan
- Department of Otolaryngology Head and Neck Surgery, Sichuan Academy of Medical Science, Sichuan Provincial People's Hospital, Chengdu, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
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Chorney SR, Elden LM, Giordano T, Kazahaya K, Rizzi MD, Zur KB, Dedhia K. Algorithm-Based Pediatric Otolaryngology Management During the COVID-19 Global Pandemic: A Children’s Hospital of Philadelphia Clinical Consensus. Otolaryngol Head Neck Surg 2020; 163:25-37. [DOI: 10.1177/0194599820923633] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
ObjectiveThe coronavirus disease 2019 (COVID-19) pandemic requires clinicians to explore alternatives to routine patient management. Otolaryngologists caring for children commonly depend on physical examination, laboratory data, and ambulatory surgical procedures. Limiting patient care, mindful allocation of resources, and concern for safety have challenged all aspects of our health care system. This evidence-based clinical consensus is designed to guide practitioners of pediatric otolaryngology for common scenarios during this time.Data SourcesPeer-reviewed literature, published reports, institutional guidelines, and expert consensus.Review MethodsA clinical consensus on 6 common scenarios in pediatric otolaryngology developed with evidence-based strategies.ConclusionsProviders should suspend all in-person nonessential office visits and elective surgical procedures. An emphasis on medical management and caregiver education will provide reasonable approaches to many of the common outpatient concerns. Surgery for chronic otitis media, obstructive sleep apnea, and acute rhinosinusitis should occur only in response to severe complications or failure of medical regimens. The approach to the pediatric neck mass focuses on timely management for oncologic etiologies and cautious surgical intervention for abscess drainage or tissue sampling. Finally, epistaxis and otorrhea must be triaged and addressed without the usual ambulatory procedures.Implications for PracticeAdaptation of practice patterns during this unprecedented moment for our health care system requires thoughtful planning. The strategies described allow for safe handling of common pediatric otolaryngology diagnoses. Ultimately, otolaryngologists must be stewards of our global health community while advocating for the care of individual pediatric patients.
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Affiliation(s)
- Stephen R. Chorney
- Division of Otolaryngology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology–Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Lisa M. Elden
- Division of Otolaryngology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology–Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Terri Giordano
- Division of Otolaryngology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Ken Kazahaya
- Division of Otolaryngology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology–Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mark D. Rizzi
- Division of Otolaryngology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology–Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Karen B. Zur
- Division of Otolaryngology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology–Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kavita Dedhia
- Division of Otolaryngology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology–Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Enhanced mitochondrial membrane potential and ATP synthesis by photobiomodulation increases viability of the auditory cell line after gentamicin-induced intrinsic apoptosis. Sci Rep 2019; 9:19248. [PMID: 31848399 PMCID: PMC6917700 DOI: 10.1038/s41598-019-55711-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 11/29/2019] [Indexed: 11/09/2022] Open
Abstract
Photobiomodulation (PBM) has been suggested to have a therapeutic effect on irreversible hearing loss induced by aminoglycosides, including gentamicin (GM). However, its intracellular mechanism(s) in GM-induced ototoxicity remain poorly understood. In the present study, we investigated the effect of PBM in GM-induced ototoxicity in auditory cells. We tried to characterize the downstream process by PBM, and the process that triggered the increased cell viability of auditory cells. As a result, the effects of PBM against GM-induced ototoxicity by increasing ATP levels and mitochondrial membrane potential was confirmed. These results suggest a theory to explain the therapeutic effects and support the use of PBM for aminoglycoside-induced hearing loss.
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Evaluation of Mitoquinone for Protecting Against Amikacin-Induced Ototoxicity in Guinea Pigs. Otol Neurotol 2018; 39:111-118. [PMID: 29194212 DOI: 10.1097/mao.0000000000001638] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
HYPOTHESIS Mitoquinone (MitoQ) attenuates amikacin ototoxicity in guinea pigs. BACKGROUND MitoQ, a mitochondria-targeted derivative of the antioxidant ubiquinone, has improved bioavailability and demonstrated safety in humans. Thus, MitoQ is a promising therapeutic approach for protecting against amikacin-induced ototoxicity. METHODS Both oral and subcutaneous administrations of MitoQ were tested. Amikacin-treated guinea pigs (n = 12-18 per group) received water alone (control) or MitoQ 30 mg/l-supplemented drinking water; or injected subcutaneously with 3 to 5 mg/kg MitoQ or saline (control). Auditory brainstem responses and distortion product otoacoustic emissions were measured before MitoQ or control solution administration and after amikacin injections. Cochlear hair cell damage was assessed using scanning electron microscopy and Western blotting. RESULTS With oral administration, animals that received 30 mg/l MitoQ had better hearing than controls at only 24 kHz at 3-week (p = 0.017) and 6-week (p = 0.027) post-amikacin. With subcutaneous administration, MitoQ-injected guinea pigs had better hearing than controls at only 24 kHz, 2-week post-amikacin (p = 0.013). Distortion product otoacoustic emission (DPOAE) amplitudes were decreased after amikacin injections, but were not different between treatments (p > 0.05). Electron microscopy showed minor difference in outer hair cell loss between treatments. Western blotting demonstrated limited attenuation of oxidative stress in the cochlea of MitoQ-supplemented guinea pigs. CONCLUSIONS Oral or subcutaneous MitoQ provided limited protection against amikacin-induced hearing loss and cochlear damage in guinea pigs. Other strategies for attenuating aminoglycoside-induced ototoxicity should be explored.
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Chee J, Pang KW, Yong JM, Ho RCM, Ngo R. Topical versus oral antibiotics, with or without corticosteroids, in the treatment of tympanostomy tube otorrhea. Int J Pediatr Otorhinolaryngol 2016; 86:183-8. [PMID: 27260604 DOI: 10.1016/j.ijporl.2016.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 04/21/2016] [Accepted: 05/05/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Antibiotic treatment is the standard of care for tympanostomy tube otorrhea. This meta-analysis aims to evaluate the efficacy of topical antibiotics with or without corticosteroids versus oral antibiotics in the treatment of tube otorrhea in children. DATA SOURCES MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and ProQuest. REVIEW METHODS The above databases were searched using a search strategy for randomized controlled trials for optimal treatment of tube otorrhea in the pediatric population. PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines were followed. Primary outcome was cure (i.e. clearance of otorrhea) at 2-3 weeks. Secondary outcomes were microbiological eradication and complications such as dermatitis and diarrhea. The incidence of these events was defined as dichotomous variables and expressed as a risk ratio (RR) and number needed to benefit (NNTB) in a random-effects model. RESULTS We identified 1491 articles and selected 4 randomized controlled trials which met our inclusion criteria. Topical treatment had better cure (NNTB = 4.7, pooled RR = 1.35, p < 0.001) and microbiological eradication (NNTB = 3.5, pooled RR = 1.47, p < 0.001 among 3 of the studies) than oral antibiotics. Oral antibiotics had higher risk of diarrhea (pooled RR = 21.5, 95% CI 8.00-58.0, p < 0.001, Number needed to harm (NNTH) = 5.4) and dermatitis (pooled RR = 3.14, 95% CI 1.20-8.20, p = 0.019, NNTH = 32). The use of topical steroids in addition to topical antibiotics was associated with a higher cure rate (pooled RR = 1.59, p < 0.001 vs pooled RR = 1.57, p = 0.293). CONCLUSION Topical antibiotics should be the recommended treatment for management of tympanostomy tube otorrhea in view of its significantly improved clinical and microbiological efficacy with lower risk of systemic toxicity as compared to oral antibiotics. Further research is necessary to confirm the benefits of topical corticosteroids as an adjunct to topical antibiotics.
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Affiliation(s)
- Jeremy Chee
- National University Health System, Singapore.
| | | | - Jui May Yong
- Department of Otolaryngology-Head and Neck Surgery, National University Health System, Singapore
| | - Roger Chun-Man Ho
- Department of Psychological Medicine, University Medicine Cluster, National University Health System, Singapore
| | - Raymond Ngo
- Department of Otolaryngology-Head and Neck Surgery, National University Health System, Singapore
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Sagit M, Korkmaz F, Gürgen SG, Gundogdu R, Akcadag A, Ozcan I. Quercetine attenuates the gentamicin-induced ototoxicity in a rat model. Int J Pediatr Otorhinolaryngol 2015; 79:2109-14. [PMID: 26434546 DOI: 10.1016/j.ijporl.2015.09.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/08/2015] [Accepted: 09/18/2015] [Indexed: 01/29/2023]
Abstract
OBJECTIVES The aim of this study is to evaluate the protective role of quercetin in gentamicin-induced ototoxicity through an auditory brainstem response (ABR) test and a histopathological evaluation of the cochlea. METHODS In this study, 48 female adult Sprague-Dawley rats aged 20-22 weeks and weighing 200-250g were used. An ABR test was carried out on all rats prior to drug administration, after which, the rats were divided into four groups of 12 animals each. Drug administration was gentamicin 120mg/kg plus ethanol in group one; gentamicin 120mg/kg plus quercetin 15mg/kg in group two; quercetin 15mg/kg in group three; and ethanol in group four. The drugs were administered intraperitoneally once a day for two weeks, and the ABR test was repeated after drug administration. Subsequently, the rats were sacrificed and their cochleae were dissected and examined histopathologically. RESULTS There was no significant difference between the pre-treatment ABR measurement values of the groups. However, a significant increase was detected in the ABR values in the group of rats that were administered gentamicin plus ethanol, while no statistically significant increase was found in the ABR values in the groups administered with gentamicin plus quercetin; quercetin alone; and ethanol alone. The number of TUNEL positive cells in the inner and outer hair cells in the Corti organ was found to be fewer, and Caspase 3 and 9 expressions were found to be weaker in the group receiving gentamicin plus quercetin than in the group receiving gentamicin plus ethanol. CONCLUSIONS Auditory function was detected to be significantly protected and apoptotic cells were found to be decreased when quercetin was administered together with gentamicin. From these results it was concluded that quercetin, a powerful antioxidant, attenuates ABR thresholds and histopathological lesions in the cochlea in gentamicin-induced ototoxicity in rats.
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Affiliation(s)
- Mustafa Sagit
- Kayseri Training and Research Hospital, Department of ENT, Kayseri, Turkey.
| | - Ferhat Korkmaz
- Sanliurfa Training and Research Hospital, Department of ENT, Şanlıurfa, Turkey
| | - Seren Gulsen Gürgen
- Celal Bayar University, School of Vocational Health Service, Department of Histology and Embryology, Manisa, Turkey
| | - Ramazan Gundogdu
- Kayseri Training and Research Hospital, Department of ENT, Kayseri, Turkey
| | - Alper Akcadag
- Kayseri Training and Research Hospital, Subdepartment of Audiology, Kayseri, Turkey
| | - Ibrahim Ozcan
- Kayseri Training and Research Hospital, Department of ENT, Kayseri, Turkey
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Mukherjea D, Ghosh S, Bhatta P, Sheth S, Tupal S, Borse V, Brozoski T, Sheehan KE, Rybak LP, Ramkumar V. Early investigational drugs for hearing loss. Expert Opin Investig Drugs 2014; 24:201-17. [PMID: 25243609 DOI: 10.1517/13543784.2015.960076] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Sensorineural hearing loss (HL) is becoming a global phenomenon at an alarming rate. Nearly 600 million people have been estimated to have significant HL in at least one ear. There are several different causes of sensorineural HL included in this review of new investigational drugs for HL. They are noise-induced, drug-induced, sudden sensorineural HL, presbycusis and HL due to cytomegalovirus infections. AREAS COVERED This review presents trends in research for new investigational drugs encompassing a variety of causes of HL. The studies presented here are the latest developments either in the research laboratories or in preclinical, Phase 0, Phase I or Phase II clinical trials for drugs targeting HL. EXPERT OPINION While it is important that prophylactic measures are developed, it is extremely crucial that rescue strategies for unexpected or unavoidable cochlear insult be established. To achieve this goal for the development of drugs for HL, innovative strategies and extensive testing are required for progress from the bench to bedside. However, although a great deal of research needs to be done to achieve the ultimate goal of protecting the ear against acquired sensorineural HL, we are likely to see exciting breakthroughs in the near future.
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Affiliation(s)
- Debashree Mukherjea
- Southern Illinois University School of Medicine, Department of Surgery , P.O. Box 19629, Springfield, IL 62794-9629 , USA
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Sagit M, Korkmaz F, Gürgen SG, Kaya M, Akcadag A, Ozcan I. The protective role of thymoquinone in the prevention of gentamicin ototoxicity. Am J Otolaryngol 2014; 35:603-9. [PMID: 25087465 DOI: 10.1016/j.amjoto.2014.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/02/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To investigate the potential protective effect of thymoquinone in gentamicin-induced ototoxicity through auditory brain stem responses (ABR) testing and histomorphological evaluation of the cochlea. METHODS This study was conducted on 48 adult female Sprague-Dawley rats that were randomized into 4 groups. Group 1 received intraperitoneal gentamicin; group 2 received intraperitoneal gentamicin plus corn oil solution; group 3 received intraperitoneal thymoquinone; and group 4 received intraperitoneal gentamicin plus thymoquinone. All groups received the drugs (once daily) in the above-mentioned protocols over 15 days. After conducting repeated ABR measurements, the rats were sacrificed, and their cochleae were isolated. RESULTS ABR thresholds were preserved in the gentamicin plus thymoquinone group when compared with the group receiving gentamicin alone. There were fewer TUNEL-positive cells and caspase-3 and caspase-9 expressions were weaker in the inner and outer hairy cells of the organ of Corti in the gentamicin plus thymoquinone group compared with the group receiving gentamicin alone. CONCLUSION The ABR values and number of apoptotic cells did not significantly increase in the group receiving gentamicin plus thymoquinone when compared to the group receiving gentamicin alone. Again, the cochlear histomorphological findings were supportive of the auditory findings. In light of these findings, we conclude that gentamicin-induced ototoxicity may be prevented by thymoquinone use in rats.
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Fernandes VT, Lin VYW. Development of an ototoxicity model in the adult CBA/CaJ mouse and determination of a golden window of corticosteroid intervention for otoprotection. J Otolaryngol Head Neck Surg 2014; 43:12. [PMID: 24762042 PMCID: PMC4029804 DOI: 10.1186/1916-0216-43-12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/11/2014] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE To investigate the effect of timing of dexamethasone administration on auditory hair cell survival following an ototoxic insult with kanamycin and furosemide. STUDY DESIGN Controlled experimental study. SETTING Translational science experimental laboratory. METHODS 5-6 week old CBA/CaJ mice, divided into 6 groups, were injected with kanamycin (1 mg/g SC) followed by furosemide (0.5 mg/g IP). Dexamethasone (0.1 mg/g IP) was injected at either 1 hour prior to insult, +1 hr, +6 hr, +12 hr, or +72 hr post insult. Temporal bones harvested on day 7 underwent Organ of Corti dissection. Immunohistochemical staining was performed using antibodies to myosin 7a, phalloidin, and TO-PRO. RESULTS Hair cell counts demonstrate a uniform ototoxicity model with total loss of outer hair cells (OHCs) and near-total loss of inner hair cells (IHCs). The group pre-treated with dexamethasone showed a statistically significant improvement in counts compared to controls (p = 0.004). Counts from the other experimental groups given dexamethasone after the insult were highly variable but demonstrated some apical and middle turn inner hair cell survival. CONCLUSION Treatment of systemic dexamethasone prior to ototoxic insult attenuates hair cell loss in a reliable, novel, ototoxicity model using kanamycin and furosemide in CBA/CaJ mice. Dosing with dexamethasone following ototoxic insult shows promising yet variable response in hair cell survival.
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Affiliation(s)
| | - Vincent Y W Lin
- Department of Otolaryngolgy - Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Ave, Suite M1-102, Toronto, ON M4N 3M5, Canada.
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Blakley BW, Alsaleh S, Dewji Z, Qureshy K, Berard S, Xie L. Steroids in aminoglycoside-containing ear drops: do they reduce cochlear toxicity? Laryngoscope 2013; 124:1209-13. [PMID: 24142776 DOI: 10.1002/lary.24475] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 09/07/2013] [Accepted: 10/15/2013] [Indexed: 11/10/2022]
Abstract
OBJECTIVES/HYPOTHESIS To determine whether betamethasone (BM) reduces the cochlear toxicity of otic gentamicin (GM) if given together. STUDY DESIGN Controlled animal study. METHODS Thirty-four mice were assigned at random to receive intratympanic injections of either 0.1 % BM (11 mice), 0.3% GM (13 mice), or a combination of both (GM/BM) with benzalkonium chloride (10 mice) in the left ear (treated) and saline on the right (untreated). Six injections were given on alternate days. Auditory brainstem response thresholds were assessed at 1 month, 2 months, and >2 months. RESULTS There was a significantly greater degree of hearing loss in the BM-treated ears compared to the untreated ears (6.48 dB hearing loss, P = .007) and in the GM-treated ears compared to untreated ears (6.59 dB hearing loss, P = .010,). However, otic GM/BM and benzalkonium chloride did not cause significant additional hearing loss compared with the untreated ears (3.56 dB hearing loss, P = .242). CONCLUSIONS Our data suggest that hearing loss caused by GM otic drops may be reduced by the inclusion of BM and benzalkonium chloride. Our finding that BM alone was associated with hearing loss suggests that the benzalkonium chloride may be the protective agent in combination otic drops.
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Affiliation(s)
- Brian W Blakley
- Department of Otolaryngology, University of Manitoba, Winnipeg, Manitoba, Canada
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Hughes AL, Hussain N, Pafford R, Parham K. Dexamethasone otoprotection in a multidose cisplatin ototoxicity mouse model. Otolaryngol Head Neck Surg 2013; 150:115-20. [PMID: 24233060 DOI: 10.1177/0194599813511948] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To develop a murine model for multidose administration of cisplatin that produces significant hearing threshold elevations and to use this model to assess the protective properties of intratympanic (IT) dexamethasone against cisplatin ototoxicity. STUDY DESIGN Controlled repeated measures design. SETTING Translational research laboratory. SUBJECTS AND METHODS Intraperitoneal (IP) cisplatin, 2 or 3 mg/kg/day, was administered for a total of 5 or 10 days in young CBA/J mice. Pure-tone evoked auditory brainstem response (ABR) thresholds were performed on days 7, 14, 21, and 28 to evaluate hearing threshold shifts. After development of the optimal dosing regimen, 15 mice received IT dexamethasone (24 mg/ml) in one ear and IT saline in the contralateral ear. RESULTS Significant threshold elevations were obtained for the 2 and 3 mg/kg/day 10 day groups, but both had high mortality rates and were excluded as potential multidose murine models. The 3 mg/kg/day 5 day group had a lower mortality rate and significant ABR threshold elevations for all frequencies on days 7, 14, 21, and 28. Using this dosing model, no statistically significant difference between IT dexamethasone and saline treated ears was found. CONCLUSIONS Unlike previous single dose models, IT dexamethasone did not have an otoprotective effect in a multidose murine model of cisplatin ototoxicity.
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Affiliation(s)
- Amy Lawrason Hughes
- University of Connecticut Health Center, Department of Surgery, Division of Otolaryngology-Head & Neck Surgery, Farmington, Connecticut, USA
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Van De Water TR, Abi Hachem RN, Dinh CT, Bas E, Haake SM, Hoosien G, Vivero R, Chan S, He J, Eshraghi AA, Angeli SI, Telischi FF, Balkany TJ. Conservation of Hearing and Protection of Auditory Hair Cells against Trauma-Induced Losses by Local Dexamethasone Therapy: Molecular and Genetic Mechanisms. Cochlear Implants Int 2013; 11 Suppl 1:42-55. [DOI: 10.1179/146701010x12671178390834] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Ojano-Dirain CP, Antonelli PJ. Prevention of gentamicin-induced apoptosis with the mitochondria-targeted antioxidant mitoquinone. Laryngoscope 2012; 122:2543-8. [DOI: 10.1002/lary.23593] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 05/02/2012] [Accepted: 06/22/2012] [Indexed: 11/11/2022]
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Maeda Y, Fukushima K, Kariya S, Orita Y, Nishizaki K. Intratympanic dexamethasone up-regulates Fkbp5 in the cochleae of mice in vivo. Acta Otolaryngol 2012; 132:4-9. [PMID: 22026503 DOI: 10.3109/00016489.2011.619571] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
CONCLUSIONS Quantitative, real-time RT-PCR demonstrated that intratympanic dexamethasone significantly up-regulates the expression of Fkbp5 in cochleae of mice in vivo. The immunohistochemistry results showed fundamentally ubiquitous expression of Fkbp5 in cochlear structures, with relatively strong expression in type 4 fibrocytes and weak signal in the inner hair cells. These data indicate that dexamethasone regulates gene expression at the level of transcription in vivo and that this process is basically ubiquitous in the cochlea. OBJECTIVES To demonstrate that intratympanically applied dexamethasone up-regulates Fkbp5 in the cochlea in vivo. METHODS Dexamethasone or control saline were intratympanically applied to adult C57/BL6 mice and dexamethasone-dependent changes in the levels of Fkbp5 expression in the cochlea were analyzed using quantitative real-time RT-PCR. The expression pattern of Fkbp5 in cochlea was investigated by immunohistochemistry in mice that were administered dexamethasone and in controls. RESULTS Quantitative real-time RT-PCR demonstrated significant increases of Fkbp5 expression levels in cochleae of dexamethasone-treated mice as compared with controls at 12 h after application (244.8 ± 155.5, n = 5 vs 100.0 ± 3.0, n = 6, p < 0.01). Immunohistochemistry showed fundamentally ubiquitous expression of Fkbp5 in cochlear structures, with some strongly positive fibrocytes in the spiral ligaments and weak immunoreactivity in the inner hair cells. Distribution of Fkbp5 signaling was not different between the dexamethasone-treated group and controls.
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Affiliation(s)
- Yukihide Maeda
- Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmacy, Japan.
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Kapusuz Z, Keles E, Alpay HC, Karlidag T, Kaygusuz I, Uzunlar AK, Orhan I, Yalcin S. The effect of topical ciprofloxacin and steroid-containing ear drops for chronic suppurative otitis media on the internal ear. Eur Arch Otorhinolaryngol 2011; 267:35-41. [PMID: 19554344 DOI: 10.1007/s00405-009-1012-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 06/04/2009] [Indexed: 11/24/2022]
Abstract
Aim of the study is to evaluate the effects of topical ciprofloxacin and prednisolone-containing ear drops for chronic suppurative otitis media on hearing threshold, cochlear reserve and cochlea morphology in healthy subjects and to determine the proper drug dose. Sixty-eight guinea pigs, all of which had healthy hearing, were used for the study. The first group (n = 30) was administered ciprofloxacin three times a day, the second group (n = 30) was administered prednisolone three times a day and the third group (n = 8) was administered sterile distilled water three times a day. The therapies lasted for 7 days and were administered intratympanically. The first group and second group were divided into three sub-groups of ten subjects. The first sub-group (n = 10) was administered an equivalent dose per kilogram as in humans, the second sub-group (n = 10) was administered one-third of the human-equivalent dose and the third sub-group (n = 10) was administered tenfold the human-equivalent dose. All subjects underwent brainstem evoked response audiometry (BERA) and distortion product otoacoustic emission (DPOAE) testing on the seventh and twenty-first days following the therapy. Following the tests, two subjects from each group were decapitated and examined under electron microscope. BERA and DPOAE testing results of the sub-group (n = 10) which was administered tenfold the human-equivalent dose were significantly different from the control group and other groups (P < 0.05). According to electron microscopic examination of the cochlea, the group which was administered a tenfold human-equivalent dose of intratympanic ciprofloxacin and prednisolone showed atrophy in cells and degenerations in cilia. This case was statistically significant when compared with the control group and other groups (P < 0.05). Ciprofloxacin and prednisolone applied at a human-equivalent dose per kilogram did not affect the hearing and cochlear histology of subjects.
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Affiliation(s)
- Zeliha Kapusuz
- Department of Otorhinolaryngology, Firat University Medical Faculty, 23200 Elazig, Turkey
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Murphy D, Daniel SJ. Intratympanic Dexamethasone to Prevent Cisplatin Ototoxicity. Otolaryngol Head Neck Surg 2011; 145:452-7. [DOI: 10.1177/0194599811406673] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Objective. To determine whether intratympanic administration of dexamethasone reduces ototoxicity from systemic cisplatin. Study Design. Prospective animal study. Setting. Cisplatin chemotherapy induces ototoxicity manifesting as irreversible, sensorineural hearing loss. This is due to damage to the inner ear structures by free radicals. Steroidal anti-inflammatories have been shown to reduce the formation of free radicals and protect hearing in animal models. Subjects and Methods. Pure tone auditory brainstem responses were obtained in 58 female albino guinea pigs before and 3 days after intraperitoneal (IP) cisplatin chemotherapy. Auditory brainstem responses were also taken up to 1 month after a low dose of cisplatin. Part I consisted of a dosing study to determine the optimal ototoxic dose of cisplatin. In part II, auditory brainstem response thresholds were compared after bilateral intratympanic dexamethasone doses to act as controls. For part III, the otoprotection of dexamethasone against cisplatin was tested in separate bilateral and unilateral studies. Results. IP injection of 12 mg/kg of cisplatin induced significant hearing loss (57.2 ± 4.4 dB, P < .01) with 0% mortality. Ears treated with intratympanic dexamethasone alone showed no significant threshold changes. Ears that received IP cisplatin and intratympanic dexamethasone showed reduced threshold shifts at 8 kHz when the greatest concentration of dexamethasone was administered. Conclusion. Modest intratympanic dexamethasone otoprotection of the guinea pig ear was greatest at the highest concentration tested and occurred in a frequency-dependent manner. Intratympanic dexamethasone presents as a safe, simple, and effective treatment modality to minimize cisplatin ototoxicity without interfering with the chemotherapeutic effects of cisplatin.
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Affiliation(s)
- Denise Murphy
- McGill Auditory Sciences Laboratory, McGill University, Montreal, Quebec, Canada
| | - Sam J. Daniel
- McGill Auditory Sciences Laboratory, McGill University, Montreal, Quebec, Canada
- Department of Otolaryngology, Head and Neck Surgery, McGill University, Montreal Children’s Hospital, Montreal, Quebec, Canada
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Mukherjea D, Rybak LP, Sheehan KE, Kaur T, Ramkumar V, Jajoo S, Sheth S. The design and screening of drugs to prevent acquired sensorineural hearing loss. Expert Opin Drug Discov 2011; 6:491-505. [PMID: 22646075 DOI: 10.1517/17460441.2011.562887] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Sensorineural hearing loss affects a high percentage of the population. Ototoxicity is a serious and pervasive problem in patients treated with cisplatin. Strategies to ameliorate ototoxicity without compromising on antitumor activity of treatments are urgently needed. Similar problems occur with aminoglycoside antibiotic therapy for infections. Noise-induced hearing loss affects a large number of people. The use of ear protection is not always possible or effective. The prevention of hearing loss with drug therapy would have a huge impact in reducing the number of people with hearing loss from these major causes. AREAS COVERED This review discusses significant research findings dealing with the use of protective agents against hearing loss caused by cisplatin, aminoglycoside antibiotics and noise trauma. The efficacy in animal studies and the application of these protective agents in clinical trials that are ongoing are presented. EXPERT OPINION The reader will gain new insights into current and projected future strategies to prevent sensorineural hearing loss from cisplatin chemotherapy, aminoglycoside antibiotic therapy and noise exposure. The future appears to offer numerous agents to prevent hearing loss caused by cisplatin, aminoglycoside antibiotics and noise. Novel delivery systems will provide ways to guide these protective agents to the desired target areas in the inner ear and circumvent problems with therapeutic interference of antitumor and antibiotics agents as well as minimize undesired side effects.
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Affiliation(s)
- Debashree Mukherjea
- Southern Illinois University, School of Medicine, Department of Surgery , P.O. Box 19653, Springfield, IL 62794-9653 , USA
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Maeda Y, Fukushima K, Hirai M, Kariya S, Smith RJH, Nishizaki K. Microarray analysis of the effect of dexamethasone on murine cochlear explants. Acta Otolaryngol 2010; 130:1329-34. [PMID: 20735180 DOI: 10.3109/00016489.2010.498836] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
CONCLUSIONS The microarray analysis identified 39 genes up- or down-regulated by dexamethasone in the cultured tissue of mice cochlea. Of the eight genes most highly affected, several are suggested to have protective effects in the traumatized inner ear (Fkbp5, Glucocorticoid-induced leucine zipper (Gilz), glutathione peroxidase 3) and for others, a plausible mechanism of action can be offered (claudin 10, glutamate-ammonia ligase). The present data may support the use of dexamethasone to treat acute sensorineural hearing loss. It is warrantable to test these results in the in vivo cochlea. OBJECTIVES To identify genes whose expression is markedly up- or down-regulated by dexamethasone in the cochlear tissue. METHODS Murine cochlear tissue was cultured with or without dexamethasone for 48 h in vitro. The gene expression profiles were compared between the dexamethasone-treated and untreated cochlear tissue using a microarray that covers 33 696 transcripts (24 878 genes) of mice and quantitative real-time RT-PCR. RESULTS The microarray analysis identified 39 genes that are up- or down-regulated by more than twofold in the presence of dexamethasone in the cochlear culture. Genes up- or down-regulated by at least threefold include Fkbp5, Gilz, glutathione peroxidase 3, claudin 10, glutamate-ammonia ligase, proteoglycan 1, integrin beta-like 1, and alpha subunit of glycoprotein hormone.
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Affiliation(s)
- Yukihide Maeda
- Department of Otolaryngology - Head and Neck Surgery, Okayama University Graduate School of Medicine, Okayama, Japan.
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Scheenstra RJ, Heijerman HGM, Zuur CL, Touw DJ, Rijntjes E. No hearing loss after repeated courses of tobramycin in cystic fibrosis patients. Acta Otolaryngol 2010; 130:253-8. [PMID: 19479457 DOI: 10.3109/00016480903015150] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION Our results indicate that repeated treatment courses with tobramycin 10 mg/kg (twice daily for 3 weeks) may be safely applied in cystic fibrosis (CF) patients with respect to ototoxicity. The risk of hearing loss in this patient group is less than expected, which could be explained by either unfavourable baseline audiometry or the use of unidentified protective medication, or both. However, due to large inter-individual variations, audiometry screening remains important with respect to the detection of individual outliers. OBJECTIVES Tobramycin is frequently prescribed for CF patients. In this study, hearing loss due to cumulative tobramycin exposure in adult CF patients was investigated. PATIENTS AND METHODS We retrospectively investigated 19 patients with both baseline and follow-up audiometry before and after repeated courses of intravenous tobramycin (10 mg/kg/day in twice daily administrations for 3 weeks). Pure tone audiometry was performed at 0.250-16 kHz. RESULTS After repeated courses of tobramycin (median 3, range 1-8), the mean increase per frequency was 2.1 dB (median 0.5 dB, SD 12.6) with large (inter-individual) variations (range -23.5 to 34.5 dB). The pure tone averages (PTA) at 1-2-4 kHz and 8-10-12 kHz increased 1.4 dBHL and 2.3 dBHL, respectively, but were neither statistically significant, nor correlated with the cumulative tobramycin exposure.
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Affiliation(s)
- Renske J Scheenstra
- Department of Otorhinolaryngology, Head and Neck Surgery, The Netherlands Cancer Institute, 1066 CXAmsterdam, The Netherlands.
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Hoang KN, Dinh CT, Bas E, Chen S, Eshraghi AA, Van De Water TR. Dexamethasone treatment of naïve organ of Corti explants alters the expression pattern of apoptosis-related genes. Brain Res 2009; 1301:1-8. [DOI: 10.1016/j.brainres.2009.08.097] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 08/25/2009] [Accepted: 08/26/2009] [Indexed: 12/20/2022]
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Abstract
HYPOTHESIS Intratympanic (IT) application of dexamethasone will reduce ototoxicity associated with systemic cisplatin therapy. BACKGROUND Cisplatin is a common chemotherapeutic drug often dose-limited by ototoxicity attributed to the formation of reactive oxygen and nitrogen species damaging critical inner ear structures. Steroids have been shown to reduce formation of reactive oxygen species and thus may reduce ototoxicity. In the present pilot study, we test this hypothesis by IT administration of dexamethasone in a novel murine model of cisplatin ototoxicity. METHODS Click- and pure-tone-evoked auditory brainstem responses (ABRs) in young CBA/J mice were measured. The first phase consisted of a dosing study to identify the optimal cisplatin dose for ototoxicity. In the next phase, ABR thresholds were measured in cisplatin-treated mice after 5 days of IT injection of 24 mg/ml of dexamethasone in 1 ear and normal saline in the opposite ear to serve as controls. RESULTS Intraperitoneal injection of 14 mg/kg of cisplatin induces significant hearing loss (click-evoked ABR threshold elevation = 12 +/- 7 dB, mu +/- standard error of the mean) with acceptable mortality (20%). The ears that received IT dexamethasone in cisplatin-treated mice had minimal ABR threshold shifts with the click, 8 and 16 kHz of stimuli. There was no significant difference between IT dexamethasone and IT saline ears at 32 kHz. CONCLUSION IT dexamethasone protected the mouse ear against cisplatin-induced ototoxicity in a frequency-dependent manner. The present results suggest that IT dexamethasone may be a safe, simple, and effective intervention that minimizes cisplatin ototoxicity without interfering with the chemotherapeutic actions of cisplatin.
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Eshraghi AA, Adil E, He J, Graves R, Balkany TJ, Van De Water TR. Local Dexamethasone Therapy Conserves Hearing in an Animal Model of Electrode Insertion Trauma-Induced Hearing Loss. Otol Neurotol 2007; 28:842-9. [PMID: 17471110 DOI: 10.1097/mao.0b013e31805778fc] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
HYPOTHESIS The progressive loss of hearing that develops after electrode insertion trauma (EIT) can be attenuated by local dexamethasone (DXM) therapy. BACKGROUND Hearing loss (HL) that develops after cochlear implant EIT occurs in two stages in laboratory animals, that is, an immediate loss followed by a progressive loss. Direct infusion of DXM into the guinea pig cochlea can attenuate both ototoxin- and noise-induced HL. MATERIALS AND METHODS Auditory-evoked brainstem responses (ABRs) of guinea pigs were measured for 4 frequencies (i.e., 0.5, 1, 4, and 16 kHz) before, immediately after, and more than 30 days post-EIT for experimental (EIT,EIT + artificial perilymph, and EIT + DXM) and for the contralateral unoperated cochleae of each group. An electrode analog of 0.14-mm diameter was inserted through a basal turn cochleostomy for a depth of 3 mm and withdrawn. DXM in artificial perilymph was delivered immediately post-EIT into the scala tympani via a miniosmotic pump for 8 days. RESULTS The ABR thresholds of EIT animals increased progressively post-EIT. Contralateral unoperated cochleae had no significant changes in ABR thresholds. Immediately post-EIT, that is, Day 0, the DXM-treated animals exhibited a significant HL at 1, 4, and 16 kHz, but this HL was no longer significant by Day 30 compared with contralateral control ears. CONCLUSION The results from immediate local treatment of the cochlea with DXM in an animal model of EIT-induced HL suggest a novel therapeutic strategy for hearing conservation by attenuating the progressive HL that can result from the process of electrode array insertion during cochlear implantation.
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Affiliation(s)
- Adrien A Eshraghi
- Cochlear Implant Research Program, University of Miami Ear Institute, Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, FL, USA
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Drobbin MT, Phelan ST, Antonelli PJ. Dexamethasone does not alter in vitro antibacterial efficacy of gentamicin. Otolaryngol Head Neck Surg 2007; 136:769-72. [PMID: 17478213 DOI: 10.1016/j.otohns.2006.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2006] [Accepted: 11/06/2006] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Aminoglycoside ototoxicity may be mitigated by administration of dexamethasone; however, dexamethasone could theoretically impair its antibacterial properties. The purpose of this experiment was to determine if dexamethasone decreases the antibacterial activity of gentamicin against Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA). STUDY DESIGN In vitro microbiological assay. METHODS Four separate trials of minimum inhibitory concentration (MIC) testing were performed for gentamicin against five PA strains and six SA strains, with and without the addition of high and low concentrations of dexamethasone. RESULTS MICs were not changed by more than one dilution with the addition of either high or low concentrations of dexamethasone for any of the PA and SA strains. CONCLUSION Dexamethasone does not impair the antibacterial efficacy of gentamicin for PA and SA. This supports the role of dexamethasone as an oto-protectant with aminoglycoside therapy.
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Affiliation(s)
- Michael T Drobbin
- Department of Otolaryngology, University of Florida, Gainesville, FL 32610, USA
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Nagashima R, Ogita K. Enhanced biosynthesis of glutathione in the spiral ganglion of the cochlea after in vivo treatment with dexamethasone in mice. Brain Res 2006; 1117:101-8. [PMID: 16949561 DOI: 10.1016/j.brainres.2006.07.113] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2006] [Revised: 07/27/2006] [Accepted: 07/31/2006] [Indexed: 11/23/2022]
Abstract
Glucocorticoids have been widely used as a therapeutic drug for sudden sensorineural hearing loss. However, very little is known about the mechanism(s) underlying the protective effect of glucocorticoids against hearing loss. As an approach toward elucidating the mechanism(s), we evaluated the effects of dexamethasone (DEX) treatment on the biosynthesis of GSH in the mouse cochlea in vivo. The systemic administration of DEX led to a significant increase in the total GSH level in the cochlea 2 to 24 h later. This DEX-induced increase in GSH occurred selectively in the spiral ganglion, but not significantly in the lateral wall tissues or in the organ of Corti. Furthermore, RT-PCR analysis revealed that DEX treatment resulted in enhanced expression of gamma-glutamylcysteine synthetase (gamma-GCS), which is the rate-limiting enzyme for de novo GSH synthesis, 1 to 24 h after the treatment. In addition to enhancing GSH biosynthesis, DEX treatment was effective in reducing lipid peroxidation in the cochlea. Taken together, DEX has the ability to facilitate GSH biosynthesis through enhanced expression of gamma-GCS in the cochlear spiral ganglion.
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Affiliation(s)
- Reiko Nagashima
- Department of Pharmacology, Setsunan University Faculty of Pharmaceutical Sciences, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
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Tabuchi K, Oikawa K, Murashita H, Hoshino T, Tsuji S, Hara A. Protective effects of glucocorticoids on ischemia-reperfusion injury of outer hair cells. Laryngoscope 2006; 116:627-9. [PMID: 16585870 DOI: 10.1097/01.mlg.0000200963.69342.d7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE This animal study aimed to investigate effects of glucocorticoids on the functional recovery of outer hair cells (OHCs) after transient ischemia. METHODS Distortion-product otoacoustic emission (DPOAE) was examined before, during, and after transient cochlear ischemia of 30 minutes using albino guinea pigs. RESULTS DPOAE decreased to noise level during ischemia. On recirculation, DPOAE initially recovered with time until 20 minutes after the onset of reperfusion, but thereafter, the DPOAE level gradually decreased toward the noise level in the control animals. Prednisolone and methylprednisolone significantly improved the DPOAE level 60 minutes after the onset of reperfusion. CONCLUSIONS The present findings suggest that glucocorticoids possess protective effects against ischemia-reperfusion injury of OHCs.
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Affiliation(s)
- Keiji Tabuchi
- Department of Otolaryngology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.
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Abstract
Two major classes of drugs currently in clinical use can cause permanent hearing loss. Aminoglycoside antibiotics have a major role in the treatment of life-threatening infections and platinum-based chemotherapeutic agents are highly effective in the treatment of malignant disease. Both damage the hair cells of the inner ear, resulting in functional deficits. The mechanisms underlying these troublesome side effects are thought to involve the production of reactive oxygen species in the cochlea, which can trigger cell-death pathways. One strategy to protect the inner ear from ototoxicity is the administration of antioxidant drugs to provide upstream protection and block the activation of cell-death sequences. Downstream prevention involves the interruption of the cell-death cascade that has already been activated, to prevent apoptosis. Challenges and opportunities exist for appropriate drug delivery to the inner ear and for avoiding interference with the therapeutic efficacy of both categories of ototoxic drugs.
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Affiliation(s)
- Leonard P Rybak
- Department of Surgery, Southern Illinois University, School of Medicine, P.O. Box 19653, Springfield, IL 62794-9653, USA.
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Safety and Efficacy of Topical Steroids with and without Topical Antibiotics. EAR, NOSE & THROAT JOURNAL 2005. [DOI: 10.1177/014556130508410s306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Indudharan R, Valuyeetham KA, Raju SS. Role of glucocorticoids in ototopical antibiotic-steroid preparations in the treatment of chronic suppurative otitis media. Arch Med Res 2005; 36:154-8. [PMID: 15847949 DOI: 10.1016/j.arcmed.2004.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Revised: 11/19/2004] [Accepted: 11/19/2004] [Indexed: 11/26/2022]
Abstract
BACKGROUND It is conventional to use antibiotic-steroid combination eardrops, although the advantage of steroid combination has not been substantiated. The present prospective randomized comparative study is designed to assess the role of glucocorticoids in ototopical antibiotic-steroid preparations in the treatment of chronic suppurative otitis media (CSOM). METHODS Pre-treatment clinical assessment, bacteriology of the middle ear discharge and pure tone audiogram were done. CSOM with organisms sensitive to gentamicin were treated either with plain gentamycin (GM) or gentamycin steroid combination (GM-S) eardrops for a period of 3 weeks. Post-treatment clinical, bacteriological and audiogram response was recorded 1 week after discontinuing the eardrops. The post-treatment clinical improvement, bacteriologic improvement and changes in hearing threshold at speech frequencies were analyzed by using unpaired Student's t test and chi(2) tests. RESULTS The most common organism associated with CSOM was Pseudomonas aeruginosa (33.92%). Clinical improvement was seen in 87.7 and 86.5% cases but bacteriological improvement in only 82.5 and 75% of cases treated with GM and GM-S (p >0.05), respectively. On comparing the pre- and post-treatment pure tone audiograms in 95 patients, 28.9% treated with GM and 30% with GM-S showed deterioration in bone conduction threshold above 5 dB (p >0.05) at speech frequencies. The mean increase in bone conduction in the two groups was 7.7 and 8.57 dB (p >0.05), respectively. CONCLUSIONS Our results indicate that there is no difference in the clinical and bacteriological improvement or ototoxicity either with topical GM or GM-S. Hence, we conclude that it is unnecessary to combine steroids with topical antibiotic preparations for the management of CSOM.
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Affiliation(s)
- Ramunnikutty Indudharan
- Department of Otorhinolaryngology, School of Medical Sciences, Universiti Sains Malaysia, Malaysia
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Nagashima R, Sugiyama C, Yoneyama M, Ogita K. Transcriptional Factors in the Cochlea Within the Inner Ear. J Pharmacol Sci 2005; 99:301-6. [PMID: 16327216 DOI: 10.1254/jphs.cpj05004x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Differential regulation of gene expression by transcription factors is widely viewed as one of the principal mechanisms guiding development. Although numerous DNA binding proteins have been identified in various tissues, the role of individual transcription factors in the differentiation of specific cell groups, such as those populating the inner ear, is just beginning to be elucidated. It is known that transcription factors are induced in response to many signals that lead to cell growth, differentiation, inflammatory responses, the regulation of apoptosis, and neoplastic transformation. There are various transcription factors in the cochlea of the inner ear. These include activator protein-1 and nuclear factor-kappa B, glucocorticoid receptor, and so on. Based on recent reports and our investigation, in this article we review possible functions and expression of these transcription factors.
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Affiliation(s)
- Reiko Nagashima
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Osaka, Japan
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