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Pecha PP, Almishaal AA, Mathur PD, Hillas E, Johnson T, Price MS, Haller T, Yang J, Rajasekaran NS, Firpo MA, Park AH. Role of Free Radical Formation in Murine Cytomegalovirus-Induced Hearing Loss. Otolaryngol Head Neck Surg 2020; 162:709-717. [PMID: 32041493 DOI: 10.1177/0194599820901485] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES The goal of the study was to determine whether reactive oxygen species (ROS) mediates cytomegalovirus (CMV)-induced labyrinthitis. STUDY DESIGN Murine model of CMV infection. SETTING University of Utah laboratory. SUBJECTS AND METHODS Nrf2 knockout mice were inoculated with murine CMV. Auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs) were then performed on these and uninfected controls. BALB/c mice were inoculated with murine CMV to determine whether a marker for ROS production, dihydroethidium (DHE), is expressed 7 days after inoculation. Finally, 2 antioxidants-D-methionine and ACE-Mg (vitamins A, C, and E with magnesium)-were administered 1 hour before and after infection in inoculated mice for 14 days. Temporal bones were harvested at postnatal day 10 for DHE detection. ABR and DPOAE testing was done at postnatal day 30. Scanning electron microscopy was also performed at postnatal day 30 to evaluate outer hair cell integrity. RESULTS Nrf2-infected mice had worse hearing than uninfected mice (P < .001). A statistically significant increase in DHE fluorescence was detected in BALB/c-infected mice as compared with uninfected mice 7 days after inoculation. D-methionine- and ACE-Mg-treated mice demonstrated an attenuation of the DHE fluorescence and a significant improvement in ABR and DPOAE thresholds when compared with untreated infected controls (P < .0001). Scanning electron microscopy demonstrated less outer hair cell loss in the treated versus untreated infected controls. CONCLUSION These results demonstrate for the first time that excessive ROS mediates CMV-induced hearing loss in a mouse model.
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Affiliation(s)
- Phayvanh P Pecha
- Division of Pediatric Otolaryngology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ali A Almishaal
- College of Applied Medical Sciences, University of Hail, Hail, Saudi Arabia
| | - Pranav D Mathur
- Otonomy Inc, San Diego, California, USA.,Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, USA
| | - Elaine Hillas
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Taelor Johnson
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Melissa S Price
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Travis Haller
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Jun Yang
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, USA.,Department of Ophthalmology, University of Utah, Salt Lake City, UT, USA
| | - Namakkal S Rajasekaran
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Division of Cardiovascular Medicine, Department of Medicine, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Matthew A Firpo
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Albert H Park
- College of Applied Medical Sciences, University of Hail, Hail, Saudi Arabia.,Division of Otolaryngology-Head and Neck Surgery, University of Utah, Salt Lake City, Utah, USA
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Spankovich C, Le Prell CG. The role of diet in vulnerability to noise-induced cochlear injury and hearing loss. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:4033. [PMID: 31795697 DOI: 10.1121/1.5132707] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The influence of dietary nutrient intake on the onset and trajectory of hearing loss during aging and in mediating protection from challenges such as noise is an important relationship yet to be fully appreciated. Dietary intake provides essential nutrients that support basic cellular processes related to influencing cellular stress response, immune response, cardiometabolic status, neural status, and psychological well-being. Dietary quality has been shown to alter risk for essentially all chronic health conditions including hearing loss and tinnitus. Evidence of nutrients with antioxidant, anti-inflammatory, and anti-ischemic properties, and overall healthy diet quality as otoprotective strategies are slowly accumulating, but many questions remain unanswered. In this article, the authors will discuss (1) animal models in nutritional research, (2) evidence of dietary nutrient-based otoprotection, and (3) consideration of confounds and limitations to nutrient and dietary study in hearing sciences. Given that there are some 60 physiologically essential nutrients, unraveling the intricate biochemistry and multitude of interactions among nutrients may ultimately prove infeasible; however, the wealth of available data suggesting healthy nutrient intake to be associated with improved hearing outcomes suggests the development of evidence-based guidance regarding diets that support healthy hearing may not require precise understanding of all possible interactions among variables. Clinical trials evaluating otoprotective benefits of nutrients should account for dietary quality, noise exposure history, and exercise habits as potential covariates that may influence the efficacy and effectiveness of test agents; pharmacokinetic measures are also encouraged.
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Affiliation(s)
- Christopher Spankovich
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA
| | - Colleen G Le Prell
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
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Abstract
There is an urgent need for otoprotective drug agents. Prevention of noise-induced hearing loss continues to be a major challenge for military personnel and workers in a variety of industries despite the requirements that at-risk individuals use hearing protection devices such as ear plugs or ear muffs. Drug-induced hearing loss is also a major quality-of-life issue with many patients experiencing clinically significant hearing loss as a side effect of treatment with life-saving drug agents such as cisplatin and aminoglycoside antibiotics. There are no pharmaceutical agents approved by the United States Food and Drug Administration for the purpose of protecting the inner ear against damage, and preventing associated hearing loss (otoprotection). However, a variety of preclinical studies have suggested promise, with some supporting data from clinical trials now being available as well. Additional research within this promising area is urgently needed.
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Affiliation(s)
- Colleen G Le Prell
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas
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Sha SH, Schacht J. Emerging therapeutic interventions against noise-induced hearing loss. Expert Opin Investig Drugs 2016; 26:85-96. [PMID: 27918210 DOI: 10.1080/13543784.2017.1269171] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Noise-induced hearing loss (NIHL) due to industrial, military, and recreational noise exposure is a major, but also potentially preventable cause of acquired hearing loss. For the United States it is estimated that 26 million people (15% of the population) between the ages of 20 and 69 have a high-frequency NIHL at a detriment to the quality of life of the affected individuals and great economic cost to society. Areas covered: This review outlines the pathology and pathophysiology of hearing loss as seen in humans and animal models. Results from molecular studies are presented that have provided the basis for therapeutic strategies successfully applied to animals. Several compounds emerging from these studies (mostly antioxidants) are now being tested in field trials. Expert opinion: Although no clinically applicable intervention has been approved yet, recent trials are encouraging. In order to maximize protective therapies, future work needs to apply stringent criteria for noise exposure and outcome parameters. Attention needs to be paid not only to permanent NIHL due to death of sensory cells but also to temporary effects that may show delayed consequences. Existing results combined with the search for efficacious new therapies should establish a viable treatment within a decade.
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Affiliation(s)
- Su-Hua Sha
- a Department of Pathology and Laboratory Medicine , Medical University of South Carolina , Charleston , SC , USA
| | - Jochen Schacht
- b Kresge Hearing Research Institute , University of Michigan , Ann Arbor , MI , USA
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Le Prell CG, Fulbright A, Spankovich C, Griffiths SK, Lobarinas E, Campbell KCM, Antonelli PJ, Green GE, Guire K, Miller JM. Dietary supplement comprised of β-carotene, vitamin C, vitamin E, and magnesium: failure to prevent music-induced temporary threshold shift. AUDIOLOGY AND NEUROTOLOGY EXTRA 2016; 6:20-39. [PMID: 27990155 DOI: 10.1159/000446600] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
This study examined potential prevention of music-induced temporary threshold shift (TTS) in normal-hearing participants. A dietary supplement composed of β-carotene, vitamins C and E, and magnesium was assessed using a randomized, placebo-controlled, double-blind study design. Dosing began 3 days prior to the music exposure with the final dose consumed approximately 30-min pre-exposure. There were no group differences in post-exposure TTS or music-induced decreases in distortion product otoacoustic emission (DPOAE) amplitude. Transient tinnitus was more likely to be reported by the treatment group, but there were no group differences in perceived loudness or bothersomeness. All subjects were monitored until auditory function returned to pre-exposure levels. Taken together, this supplement had no effect on noise-induced changes in hearing. Recommendations for future clinical trials are discussed.
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Affiliation(s)
- C G Le Prell
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Tex
| | - A Fulbright
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, Fla
| | - C Spankovich
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, Miss
| | - S K Griffiths
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, Fla
| | - E Lobarinas
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Tex
| | - K C M Campbell
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, Ill
| | - P J Antonelli
- Department of Otolaryngology, University of Florida, Gainesville, Fla
| | - G E Green
- Department of Otolaryngology, University of Michigan, Ann Arbor, Mich
| | - K Guire
- Department of Biostatistics, University of Michigan, Ann Arbor, Mich
| | - J M Miller
- Department of Otolaryngology, University of Michigan, Ann Arbor, Mich
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Stewart C, Yu Y, Huang J, Maklad A, Tang X, Allison J, Mustain W, Zhou W, Zhu H. Effects of high intensity noise on the vestibular system in rats. Hear Res 2016; 335:118-127. [PMID: 26970474 DOI: 10.1016/j.heares.2016.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/22/2016] [Accepted: 03/07/2016] [Indexed: 12/18/2022]
Abstract
Some individuals with noise-induced hearing loss (NIHL) also report balance problems. These accompanying vestibular complaints are not well understood. The present study used a rat model to examine the effects of noise exposure on the vestibular system. Rats were exposed to continuous broadband white noise (0-24 kHz) at an intensity of 116 dB sound pressure level (SPL) via insert ear phones in one ear for three hours under isoflurane anesthesia. Seven days after the exposure, a significant increase in ABR threshold (43.3 ± 1.9 dB) was observed in the noise-exposed ears, indicating hearing loss. Effects of noise exposure on vestibular function were assessed by three approaches. First, fluorescein-conjugated phalloidin staining was used to assess vestibular stereocilia following noise exposure. This analysis revealed substantial sensory stereocilia bundle loss in the saccular and utricular maculae as well as in the anterior and horizontal semicircular canal cristae, but not in the posterior semicircular canal cristae. Second, single unit recording of vestibular afferent activity was performed under pentobarbital anesthesia. A total of 548 afferents were recorded from 10 noise-treated rats and 12 control rats. Noise exposure produced a moderate reduction in baseline firing rates of regular otolith afferents and anterior semicircular canal afferents. Also a moderate change was noted in the gain and phase of the horizontal and anterior semicircular canal afferent's response to sinusoidal head rotation (1 and 2 Hz, 45°/s peak velocity). Third, noise exposure did not result in significant changes in gain or phase of the horizontal rotational and translational vestibulo-ocular reflex (VOR). These results suggest that noise exposure not only causes hearing loss, but also causes substantial damage in the peripheral vestibular system in the absence of immediate clinically measurable vestibular signs. These peripheral deficits, however, may lead to vestibular disorders over time.
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Affiliation(s)
- Courtney Stewart
- PhD Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA; Department of Otolaryngology & Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA
| | - Yue Yu
- Department of Otolaryngology & Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA
| | - Jun Huang
- Department of Otolaryngology & Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA
| | - Adel Maklad
- Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, USA
| | - Xuehui Tang
- Department of Otolaryngology & Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA
| | - Jerome Allison
- Department of Otolaryngology & Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA; Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, USA
| | - William Mustain
- Department of Otolaryngology & Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA
| | - Wu Zhou
- Department of Otolaryngology & Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA; Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, USA; Department of Neurology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Hong Zhu
- Department of Otolaryngology & Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA; Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, USA.
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Pharmacological agents used for treatment and prevention in noise-induced hearing loss. Eur Arch Otorhinolaryngol 2016; 273:4089-4101. [DOI: 10.1007/s00405-016-3936-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/10/2016] [Indexed: 12/20/2022]
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Spankovich C, Le Prell CG. Associations between dietary quality, noise, and hearing: data from the National Health and Nutrition Examination Survey, 1999-2002. Int J Audiol 2014; 53:796-809. [PMID: 24975234 DOI: 10.3109/14992027.2014.921340] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE A statistically significant relationship between dietary nutrient intake and threshold sensitivity at higher frequencies has been reported, but evidence conflicts across studies. Here, the potential interaction between noise and diet in their association to hearing was examined. DESIGN This cross-sectional analysis was based on Healthy Eating Index data and audiological threshold pure-tone averages for low (0.5 to 2 kHz) and high (3 to 8 kHz) frequencies. STUDY SAMPLE Data were drawn from the National Health and Nutrition Examination Survey, 1999-2002. RESULTS Controlling for age, sex, race/ethnicity, education, diabetes, hypertension, and smoking we found statistically significant relationships between dietary quality and high-frequency threshold sensitivity as well as noise exposure and high-frequency thresholds. In addition, there was a statistically significant interaction between dietary quality and reported noise exposure with respect to high-frequency threshold sensitivity in participants, where greater reported noise exposure and poorer diet were associated with poorer hearing (p's < 0.05). CONCLUSIONS The current findings support an association between healthier eating and better hearing at higher frequencies; the strength of this relationship varied as a function of participant noise history, with the most robust relationship in those that reported military service or firearm use.
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Affiliation(s)
- C Spankovich
- Department of Speech, Language, and Hearing Sciences, University of Florida , Gainesville , USA
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Le Prell CG, Ojano-Dirain C, Rudnick EW, Nelson MA, DeRemer SJ, Prieskorn DM, Miller JM. Assessment of nutrient supplement to reduce gentamicin-induced ototoxicity. J Assoc Res Otolaryngol 2014; 15:375-93. [PMID: 24590390 PMCID: PMC4010593 DOI: 10.1007/s10162-014-0448-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 01/28/2014] [Indexed: 12/29/2022] Open
Abstract
Gentamicin is an aminoglycoside antibiotic used to treat gram-negative bacterial infections. Treatment with this antibiotic carries the potential for adverse side effects, including ototoxicity and nephrotoxicity. Ototoxic effects are at least in part a consequence of oxidative stress, and various antioxidants have been used to attenuate gentamicin-induced hair cell death and hearing loss. Here, a combination of nutrients previously shown to reduce oxidative stress in the hair cells and attenuate hearing loss after other insults was evaluated for potential protection against gentamicin-induced ototoxicity. Guinea pigs were maintained on a nutritionally complete standard laboratory animal diet or a diet supplemented with β-carotene, vitamins C and E, and magnesium. Three diets with iterative increases in nutrient levels were screened; the final diet selected for study use was one that produced statistically reliable increases in plasma levels of vitamins C and E and magnesium. In two separate studies, significant decreases in gentamicin-induced hearing loss at frequencies including 12 kHz and below were observed, with less benefit at the higher frequencies. Consistent with the functional protection, robust protection of both the inner and outer hair cell populations was observed, with protection largely in the upper half of the cochlea. Protection was independently assessed in two different laboratories, using two different strains of guinea pigs. Additional in vitro tests did not reveal any decrease in antimicrobial activity with nutrient additives. Currently, there are no FDA-approved treatments for the prevention of gentamicin-induced ototoxicity. The current data provide a rationale for continued investigations regarding translation to human patients.
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Abstract
Trans-tympanic injection into the middle ear has long been the standard for local delivery of compounds in experimental studies. Here we demonstrate the advantages of the novel method of intra-tympanic injection through the otic bone for the delivery of compounds or siRNA into the adult mouse cochlea. First, a fluorescently-conjugated scrambled siRNA probe was applied via intra-tympanic injection into the middle ear cavity and was detected in sensory hair cells and nerve fibers as early as 6 h after the injection. The fluorescent probe was also detected in other cells of the organ of Corti, the lateral wall, and in spiral ganglion cells 48 h after the injection. Furthermore, intra-tympanic delivery of Nox3 siRNA successfully reduced immunofluorescence associated with Nox3 in outer hair cells 72 h after injection by 20%. Drug or siRNA delivery via intra-tympanic injection does not compromise the tympanic membrane or interfere with noise-induced hearing loss, while trans-tympanic injections significantly altered the cochlear response to noise exposure. In summary, intra-tympanic injection through the otic bone into the middle ear cavity provides a promising approach for delivery of compounds or siRNA to cochlear hair cells of adult mice, relevant for the study of mechanisms underlying inner ear insults and, specifically, noise-induced hearing loss.
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Affiliation(s)
- Naoki Oishi
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI 48109-5616, USA
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Le Prell CG, Johnson AC, Lindblad AC, Skjönsberg A, Ulfendahl M, Guire K, Green GE, Campbell KCM, Miller JM. Increased vitamin plasma levels in Swedish military personnel treated with nutrients prior to automatic weapon training. Noise Health 2012; 13:432-43. [PMID: 22122960 DOI: 10.4103/1463-1741.90317] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Noise-induced hearing loss (NIHL) is a significant clinical, social, and economic issue. The development of novel therapeutic agents to reduce NIHL will potentially benefit multiple very large noise-exposed populations. Oxidative stress has been identified as a significant contributor to noise-induced sensory cell death and NIHL, and several antioxidant strategies have now been suggested for potential translation to human subjects. One such strategy is a combination of beta-carotene, vitamins C and E, and magnesium, which has shown promise for protection against NIHL in rodent models, and is being evaluated in a series of international human clinical trials using temporary (military gunfire, audio player use) and permanent (stamping factory, military airbase) threshold shift models (NCT00808470). The noise exposures used in the recently completed Swedish military gunfire study described in this report did not, on average, result in measurable changes in auditory function using conventional pure-tone thresholds and distortion product otoacoustic emission (DPOAE) amplitudes as metrics. However, analysis of the plasma samples confirmed significant elevations in the bloodstream 2 hours after oral consumption of active clinical supplies, indicating the dose is realistic. The plasma outcomes are encouraging, but clinical acceptance of any novel therapeutic critically depends on demonstration that the agent reduces noise-induced threshold shift in randomized, placebo-controlled, prospective human clinical trials. Although this noise insult did not induce hearing loss, the trial design and study protocol can be applied to other populations exposed to different noise insults.
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Affiliation(s)
- C G Le Prell
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL, USA
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Le Prell CG, Dolan DF, Bennett DC, Boxer PA. Nutrient plasma levels achieved during treatment that reduces noise-induced hearing loss. Transl Res 2011; 158:54-70. [PMID: 21708356 PMCID: PMC3125531 DOI: 10.1016/j.trsl.2011.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 02/04/2011] [Accepted: 02/07/2011] [Indexed: 10/18/2022]
Abstract
Hearing loss encompasses both temporary and permanent deficits. If temporary threshold shift (TTS) and permanent threshold shift (PTS) share common pathological mechanisms, then agents that reduce PTS also should reduce TTS. Several antioxidant agents have reduced PTS in rodent models; however, reductions in TTS have been inconsistent. This study first determined whether dietary antioxidants (beta-carotene and vitamins C and E) delivered in combination with magnesium (Mg) reliably increase plasma concentrations of the active agents. Then, additional manipulations tested the hypothesis that these nutrients reduce acute TTS insult in the first 24 h after loud sound as well as longer lasting changes in hearing measured up to 7 days postnoise. Saline or nutrients were administered to guinea pigs prior to and after noise exposure. Sound-evoked electrophysiological responses were measured before noise, with tests repeated 1-h postnoise, as well as 1-day, 3-days, 5-days, and 7-days postnoise. All subjects showed significant functional recovery; subjects treated with nutrients recovered more rapidly and had better hearing outcomes at early postnoise times as well as the final test time. Thus, this combination of nutrients, which produced significant increases in plasma concentrations of vitamins C and E and Mg, effectively reduced hearing loss at multiple postnoise times. These data suggest that free radical formation contributes to TTS as well as PTS insults and suggest a potential opportunity to prevent TTS in human populations.
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Affiliation(s)
- Colleen G Le Prell
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL 32610, USA.
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Adelman C, Weinberger JM, Kriksunov L, Sohmer H. Effects of furosemide on the hearing loss induced by impulse noise. J Occup Med Toxicol 2011; 6:14. [PMID: 21548982 PMCID: PMC3118388 DOI: 10.1186/1745-6673-6-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 05/08/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The permanent hearing loss following exposure to intense noise can be due either to mechanical structural damage (tearing) caused directly by the noise or to metabolic (biochemical) damage resulting from the elevated levels of free radicals released during transduction of the sound overstimulation. Drugs which depress active cochlear mechanics (e.g. furosemide and salicylic acid) or anti-oxidants (which counteract the free radicals) are effective in reducing the threshold shift (TS) following broadband continuous noise. This study was designed to determine whether furosemide can reduce the TS following exposure to impulse noise, similar to its action with continuous broadband noise. METHODS Shortly after furosemide injection, mice were exposed to simulated M16 rifle impulse noise produced by different loudspeakers and amplifiers in different exposure settings and, in other experiments, also to actual M16 rifle shots. RESULTS Depending on the paradigm, the simulated noises either did not produce a TS, or the TS was reduced by furosemide. The drug was not effective in reducing TS resulting from actual impulse noise. CONCLUSION Simulated M16 rifle impulse noise may not truly replicate the rapid rise time and very high intensity of actual rifle shots so that the TS following exposure to such noise can be reduced by these drugs. On the other hand, actual M16 impulse noise probably causes direct (frank) mechanical damage, which is not reduced by these drugs.
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Affiliation(s)
- Cahtia Adelman
- Dept, of Physiology; Institute for Medical Research - Israel-Canada; Hebrew University-Hadassah Medical School, POB 12272, Jerusalem 91120, Israel.
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Abstract
INTRODUCTION Approximately 5% of the population worldwide suffers from industrial, military or recreational noise-induced hearing loss (NIHL) at a great economic cost and detriment to the quality of life of the affected individuals. This review discusses pharmacological strategies to attenuate NIHL that have been developed in animal models and that are now beginning to be tested in field trials. AREAS COVERED The review describes the epidemiology, pathology and pathophysiology of NIHL in experimental animals and humans. The underlying molecular mechanisms of damage are then discussed as a basis for therapeutic approaches to ameliorate the loss of auditory function. Finally, studies in military, industrial and recreational settings are evaluated. Literature was searched using the terms 'noise-induced hearing loss' and 'noise trauma'. EXPERT OPINION NIHL, in principle, can be prevented. With the current pace of development, oral drugs to protect against NIHL should be available within the next 5-10 years. Positive results from ongoing trials combined with additional laboratory tests might accelerate the time from the bench to clinical treatment.
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Affiliation(s)
- Naoki Oishi
- Kresge Hearing Research Institute, Medical Sciences Bldg I, 1150 West Medical Center Drive, Ann Arbor, MI 48109-5616, USA
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