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do Amaral JB, Peron KA, Soeiro TLT, Scott MCP, Hortense FTP, da Silva MD, França CN, Nali LHDS, Bachi ALL, de Oliveira Penido N. The inflammatory and metabolic status of patients with sudden-onset sensorineural hearing loss. Front Neurol 2024; 15:1382096. [PMID: 39015324 PMCID: PMC11250376 DOI: 10.3389/fneur.2024.1382096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 06/14/2024] [Indexed: 07/18/2024] Open
Abstract
Introduction Sudden sensorineural hearing loss (SSNHL) is a common emergency symptom in otolaryngology that requires immediate diagnosis and treatment. SSNHL has a multifactorial etiology, and its pathophysiologic mechanisms may be associated with inflammatory and metabolic changes that may affect the cochlear microenvironment or its nervous component, thus triggering the process or hindering hearing recovery. Therefore, the aim of this study was to assess metabolic and inflammatory changes to identify systemic parameters that could serve as prognostic factors for hearing recovery in patients with SSNHL. Materials and methods Thirty patients with a sudden hearing loss of at least 30 dB in three contiguous frequencies were enrolled in this study. Patients were followed up for 4 months and peripheral blood samples were collected at 7 days (V1), 30 days (V2) and 120 days (V3). Interleukins (IL)-1F7, IL-2, IL-4, IL-5, IL-6, IL-10, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α) and adiponectin were quantified in serum. In addition, lipid and glycemic profiles as well as concentration of creatinine, uric acid, fructosamine, peroxide, total proteins and albumin were analyzed. Patients underwent weekly ear-specific hearing tests with standard pure tone thresholds for frequencies of 250-8,000 Hz, speech recognition threshold and word recognition score. Results Patients with SSNHL were divided into a group of patients who did not achieve hearing recovery (n = 14) and another group who achieved complete and significant recovery (n = 16). Most serologic parameters showed no significant changes or values indicating clinical changes. However, IFN-γ levels decreased by 36.3% between V1 and V2. The cytokine TNF-α showed a statistically significant decrease from V1 to V3 (from 22.91 to 10.34 pg./mL). Adiponectin showed a decrease from 553.7 ng/mL in V1 to 454.4 ng/mL in V3. Discussion Our results show that serologic cytokine levels change in the acute phase of manifestation of SSNHL and establish a parallel between systemic changes and improvements in hearing, especially TNF-α, which showed differences in hearing recovery. The use of IFN-γ, TNF-α and adiponectin may elucidate the clinical improvement in these patients.
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Affiliation(s)
- Jônatas Bussador do Amaral
- ENT Research Lab, Department of Otorhinolaryngology—Head and Neck Surgery, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Kelly Abdo Peron
- ENT Research Lab, Department of Otorhinolaryngology—Head and Neck Surgery, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Tracy Lima Tavares Soeiro
- ENT Research Lab, Department of Otorhinolaryngology—Head and Neck Surgery, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Marina Cançado Passarelli Scott
- ENT Research Lab, Department of Otorhinolaryngology—Head and Neck Surgery, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Flávia Tatiana Pedrolo Hortense
- ENT Research Lab, Department of Otorhinolaryngology—Head and Neck Surgery, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | | | - Carolina Nunes França
- Post-Graduation Program in Health Sciences, Santo Amaro University (UNISA), São Paulo, Brazil
| | | | | | - Norma de Oliveira Penido
- ENT Research Lab, Department of Otorhinolaryngology—Head and Neck Surgery, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
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Dogan S, Huber AM, Roosli C. Treatment of Acute Otitis Media with Inner Ear Involvement in Adults. J Clin Med 2023; 12:7590. [PMID: 38137659 PMCID: PMC10743793 DOI: 10.3390/jcm12247590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/29/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
Inner ear involvement (IED) is a rare local complication of the very common acute otitis media (AOM). The most beneficial treatment for IED remains a matter of debate. The aim of this study is to analyze different treatment modalities based on hearing outcomes to contribute to the discussion of therapy for IED in AOM. This retrospective study includes 112 adult patients diagnosed with AOM with IED between 2000 and 2020. Patients either received conservative (systemic antibiotic and systemic steroid therapy), interventional (conservative plus myringotomy and tympanic tube) or operative (interventional plus antrotomy) treatment. Pre- and post-treatment pure tone audiometry was performed. The hearing outcome was compared, and hearing recovery was analyzed based on modified Siegel's criteria. The pre-treatment pure tone average (PTA) was significantly (p < 0.05) higher in the operative group than in the other groups. All treatment modalities led to a significant hearing improvement (p < 0.001). The pre- and post-treatment hearing loss was predominantly observed in high frequencies 2-4 kHz. The operative group showed the highest rate of complete hearing recovery. While all treatment modalities led to a significant improvement in hearing, the operative group showed the most beneficial hearing results in patients with high pre-treatment hearing loss. It remains to be shown if the findings in patients with high pre-treatment hearing loss can be generalized to patients with mild or moderate pre-treatment hearing loss.
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Affiliation(s)
| | | | - Christof Roosli
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, University of Zurich, 8091 Zurich, Switzerland; (S.D.)
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Wilhelm T, Stelzer T, Hagen R. Sensorineural hearing loss after otitis media with effusion and subacute mastoiditis after viral infections of the upper respiratory tract: A comparative study of conservative and surgical treatment. EAR, NOSE & THROAT JOURNAL 2017; 95:E18-27. [PMID: 27657322 DOI: 10.1177/014556131609500908] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Involvement of the middle ear after viral infections of the upper airways may lead to serous otitis media with effusion in the absence of bacterial infection. This can be accompanied by a concomitant shading of the mastoid air cells, which could manifest as a reduced opacity on computed tomography (CT) in the absence of a history of chronic mastoiditis or acute inflammatory signs. This can lead to a subsequent impairment of inner ear function. CT scans reveal an extended pneumatization of the temporal bones in affected patients. Inner ear hearing impairment can probably be attributed to a concomitant labyrinthine reaction-the so-called toxic inner ear lesion. If no remission occurs within 5 days after initial conservative treatment (paracentesis or hemorrheologic infusions), surgical treatment with a mastoidectomy can accelerate hearing restoration. We conducted a retrospective, nonrandomized study of short- and long-term hearing outcomes in patients with a toxic inner ear lesion who had been treated with conservative measures alone (CONS group) or with surgery (SURG group) in a tertiary care referral center. Our study group was made up of 52 consecutively presenting patients (57 ears) who had been seen over a 10-year period; there were 20 patients (21 ears) in the CONS group and 32 patients (36 ears) in the SURG group. Initially, 15 CONS patients (75%) and 18 SURG patients (56%) complained of dizziness or a balance disorder. The initial averaged sensorineural hearing loss (over 0.5, 1.0, 2.0, and 3.0 kHz) was 32.4 ± 15.6 dB in the CONS group and 35.4 ± 12.0 dB in the SURG group. At follow-up (mean: 31.7 mo), the SURG group experienced a significantly greater improvement in hearing (p = 0.025). We conclude that patients with viral otitis media and concomitant noninflammatory mastoiditis with impairment of inner ear function (sensorineural hearing loss) experience a better hearing outcome when a mastoidectomy is performed during primary treatment.
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Affiliation(s)
- Thomas Wilhelm
- Department of Otolaryngology, Head/Neck and Facial Plastic Surgery, Sana Kliniken Leipziger Land, Rudolf Virchow Strasse 2, 04552 Borna, Germany.
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Bluestone CD, Klein JO, Rosenfeld RM, Berman S, Casselbrant ML, Chonmaitree T, Giebink GS, Grote JJ, Ingvarsson LB, Linder T, Lous J, Maw AR, Paradise JL, Sando I, Stool SE, Takasaka T. 9. Treatment, Complications, and Sequelae. Ann Otol Rhinol Laryngol 2016. [DOI: 10.1177/00034894021110s312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Tsinaslanidou Z, Tsaligopoulos M, Angouridakis N, Vital V, Kekes G, Constantinidis J. The Expression of TNFα, IL-6, IL-2 and IL-8 in the Serum of Patients with Idiopathic Sudden Sensorineural Hearing Loss: Possible Prognostic Factors of Response to Corticosteroid Treatment. AUDIOLOGY AND NEUROTOLOGY EXTRA 2016. [DOI: 10.1159/000442016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Introduction: Idiopathic sudden sensorineural hearing loss (ISSNHL) remains one of the major unsolved otologic emergencies. A viral infection, a systemic inflammatory disorder, as well as physical, mental and metabolic stress can trigger an innate immune response in the inner ear resulting in ISSNHL. Proinflammatory cytokines play a central role in this cochlear immunological cascade. Objective: To examine the expression of proinflammatory cytokines in the serum of patients with ISSNHL in correlation with the therapeutic outcome of intravenous administration of corticosteroids. Method: Forty-three patients primarily diagnosed with ISSNHL underwent intravenous corticosteroid treatment for 8 days. The expression of tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), interleukin-2 (IL-2) and interleukin-8 (IL-8) was detected with the use of enzyme-linked immunosorbent assay in serum specimens on the 1st and 8th day of treatment and it was correlated with the treatment outcome. Results: TNFα reduction and IL-6 increase strongly correlate with a good therapeutic result [χ2(2) = 13.12, p = 0.001 and χ2(2) = 16.78, p = 0.0001]. IL-8 increase reflects negatively on the outcome, however, not in a statistically significant way. No association was established between IL-2 variations and the therapeutic outcome. Conclusions: TNFα and IL-6 can be used as prognostic factors for the treatment outcome, whereas the prognostic value of IL-8 requires further statistical confirmation.
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Wong ACY, Ryan AF. Mechanisms of sensorineural cell damage, death and survival in the cochlea. Front Aging Neurosci 2015; 7:58. [PMID: 25954196 PMCID: PMC4404918 DOI: 10.3389/fnagi.2015.00058] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/05/2015] [Indexed: 12/20/2022] Open
Abstract
The majority of acquired hearing loss, including presbycusis, is caused by irreversible damage to the sensorineural tissues of the cochlea. This article reviews the intracellular mechanisms that contribute to sensorineural damage in the cochlea, as well as the survival signaling pathways that can provide endogenous protection and tissue rescue. These data have primarily been generated in hearing loss not directly related to age. However, there is evidence that similar mechanisms operate in presbycusis. Moreover, accumulation of damage from other causes can contribute to age-related hearing loss (ARHL). Potential therapeutic interventions to balance opposing but interconnected cell damage and survival pathways, such as antioxidants, anti-apoptotics, and pro-inflammatory cytokine inhibitors, are also discussed.
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Affiliation(s)
- Ann C Y Wong
- Department of Surgery/Division of Otolaryngology, University of California, San Diego School of Medicine La Jolla, CA, USA ; Department of Physiology and Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales Sydney, NSW, Australia
| | - Allen F Ryan
- Department of Surgery/Division of Otolaryngology, University of California, San Diego School of Medicine La Jolla, CA, USA ; Veterans Administration Medical Center La Jolla, CA, USA ; Department of Neurosciences, University of California, San Diego School of Medicine La Jolla, CA, USA
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Toxic inner ear lesion following otitis media with effusion: a comparative CT-study regarding the morphology of the inner ear. Eur Arch Otorhinolaryngol 2014; 272:3635-43. [PMID: 25481029 DOI: 10.1007/s00405-014-3425-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 11/28/2014] [Indexed: 10/24/2022]
Abstract
Viral infections of the upper respiratory airways can lead to a delayed viral otitis media (VOM) caused by a diffusion of viruses/virus particles through the round window membrane and resulting in sensorineural hearing loss. The treatment of choice is immediate paracentesis, evacuation of all fluids from the middle ear cavity, and haemorrheological infusions. However, in some cases, persistent symptoms may be an indication for a surgical approach using mastoidectomy. In high-resolution computed tomography, an extended small-sized pneumatisation of the mastoid cells with complete shading was found in these non-responsive cases. Therefore, a direct means of inner ear affliction through weak parts of the labyrinthine bone may be hypothesised. Patients suffering from a toxic inner ear lesion (TIEL) following a common cold, treated over a 10-year period in a Tertiary Care Centre (N = 52, 57 ears), were identified and the morphological characteristics of the temporal bones of affected patients were examined by means of high-resolution computed tomography (hrCT). The findings were compared with a matched control group of 64 normal ears (CONT). Measurements included the grade of pneumatisation, distances within the temporal bones and Hounsfield units (HU) at defined anatomical structures. In the TIEL group, we found a small-sized pneumatisation in 79.4 % and a medium-sized pneumatisation in 10.9 %, thus differing from the CONT group and the literature data. Thickness of the bone wall of the lateral semicircular canal (LSC) and distances within the aditus ad antrum were significantly reduced in the TIEL group. HU's were markedly lower in the TIEL group at the precochlea, the LSC, and dorsolateral to the promentia of the LSC. There was a correlation between the HU's at the prominentia of the LSC and the hearing loss (p = 0.002). Persisting interosseous globuli, as described in 1897 by Paul Manasse, form an osseochondral network within the otic capsule and may be responsible for a direct means of toxic inner ear infection. The CT-morphometric results support this thesis. In the group of these patients (TIEL) a CT-scan and in non-responders to conservative treatment a surgical approach by mastoidectomy is recommended.
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Verhoeven D, Pichichero ME. Divergent mucosal and systemic responses in children in response to acute otitis media. Clin Exp Immunol 2014; 178:94-101. [PMID: 24889648 DOI: 10.1111/cei.12389] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2014] [Indexed: 12/21/2022] Open
Abstract
Acute otitis media (AOM), induced by respiratory bacteria, is a significant cause of children seeking medical attention worldwide. Some children are highly prone to AOMs, suffering three to four recurrent infections per year (prone). We previously determined that this population of children could have diminished anti-bacterial immune responses in peripheral blood that could fail to limit bacterial colonization in the nasopharynx (NP). Here, we examined local NP and middle ear (ME) responses and compared them to peripheral blood to examine whether the mucosa responses were similar to the peripheral blood responses. Moreover, we examined differences in effector cytokine responses between these two populations in the NP, ME and blood compartments at the onset of an AOM caused by either Streptococcus pneumoniae or non-typeable Haemophilus influenzae. We found that plasma effector cytokines patterned antigen-recall responses of CD4 T cells, with lower responses detected in prone children. ME cytokine levels did not mirror blood, but were more similar to the NP. Interferon (IFN)-γ and interleukin (IL)-17 in the NP were similar in prone and non-prone children, while IL-2 production was higher in prone children. The immune responses diverged in the mucosal and blood compartments at the onset of a bacterial ME infection, thus highlighting differences between local and systemic immune responses that could co-ordinate anti-bacterial immune responses in young children.
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Affiliation(s)
- D Verhoeven
- Rochester General Research Institute, Rochester General Hospital, Rochester, NY, USA
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Predictors for sensorineural hearing loss in patients with tubotympanic otitis, cholesteatoma, and tympanic membrane retractions. Otol Neurotol 2012; 33:934-40. [PMID: 22722145 DOI: 10.1097/mao.0b013e318259b885] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine predicting value of otitis type, age, gender, ear suppuration, disease duration, mucosal changes, cholesteatoma spreading, labyrinthine fistula, size, localization of tympanic membrane perforation, type and stage of its retraction and ossicular chain disruption with sensorineural hearing loss in patients with tubotympanic otitis, cholesteatoma, and tympanic membrane retractions. STUDY DESIGN Retrospective case review study. SETTING Tertiary referral center. PATIENTS Approximately 264 adult patients with unilateral chronic ear disease, 60 adult patients with tympanic membrane retractions, 78 with cholesteatoma, and 126 with tubotympanic otitis. INTERVENTIONS Otomicroscopy, pure tone audiometry, impedancemetry were carried out preoperatively. Wall up, wall down tympanoplasty, or two-stage surgery was applied depending on pathology. MAIN OUTCOME MEASURE Bone conduction thresholds for 512 to 4,096 Hz. RESULTS Mean values of bone conduction thresholds for frequencies 512 to 4,096 Hz were significantly higher in otitis groups than in healthy ears (p = 0.000), without differences between the groups. Ossicular disruption correlated with sensorineural hearing loss in cholesteatoma and tubotympanic otitis for all frequencies; long incus process destruction in tubotympanic ears showed strong negative correlation with sensorineural hearing loss for 512 to 2,048 Hz (linear regression coefficient, intercept was -2.84, -2.48, and -2.41; p = 0.0024, 0.0207, and 0.0076, respectively). Perforation size correlated with sensorineural hearing loss for 512 to 2,048 Hz in tubotympanic otitis (Log regression p = 0.0008, 0.0252, and 0.0267; odds ratio, 1.13, 1.11, and 1.06). Atelectasis correlated with sensorineural hearing loss for 4,096 Hz (p = 0.022). CONCLUSION Predictors for sensorineural hearing loss in chronic otitis are otitis itself, age, ossicular disruption, especially of long incus process, extensive labyrinthine fistula, perforation size, and type of retraction.
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Juhn S, Tsuprun V, Lee Y, Hunter B, Schachern P. Interaction between middle and inner ears in otitis media. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/16513860410000375] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Abstract
HYPOTHESIS Two Streptococcus pneumoniae proteins, pneumococcal surface protein A (PspA) and pneumolysin (Ply), have functional and histopathologic effects on the inner ear. BACKGROUND Temporary or permanent sensorineural hearing loss is known to be a sequela of pneumococcal otitis media. Several pneumococcal proteins such as PspA and Ply have been shown to contribute to the pathogenesis of the middle ear; however, effects of these proteins on the inner ear and hearing loss are unknown. METHODS Middle ears of chinchillas were inoculated with either wild-type S. pneumoniae or its mutants, deficient in PspA or Ply proteins. After 28 days, auditory brainstem response of animals was tested, and their bullae were processed for histopathologic analysis by light microscopy. RESULTS Twenty-eight days after instillation of 20 colony-forming units of wild-type pneumococci, auditory brainstem response test showed threshold changes of 10 to 15 dB for 4 to 32 kHz and more than 20 dB for 1 to 2 kHz. No significant hearing loss was observed after instillation of the same or even higher doses of isogenic S. pneumoniae mutants of PspA or Ply proteins, or saline injection, after the same period. Histologic analysis showed no fluid, inflammatory cells, or bacteria in the middle ear, indicating that hearing loss was sensorineural. Inner ear morphology showed pathologic changes in the stria vascularis, suggesting it as the target of otitis media-induced damage, which may lead to sensorineural hearing loss. CONCLUSION The virulence PspA and Ply proteins of S. pneumoniae affect the inner ear and auditory function.
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Smirnova MG, Birchall JP, Pearson JP. The immunoregulatory and allergy-associated cytokines in the aetiology of the otitis media with effusion. Mediators Inflamm 2005; 13:75-88. [PMID: 15203548 PMCID: PMC1781541 DOI: 10.1080/09629350410001688477] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2022] Open
Abstract
Inflammation in the middle ear mucosa, which can be provoked by different primary factors such as bacterial and viral infection, local allergic reactions and reflux, is the crucial event in the pathogenesis of otitis media with effusion (OME). Unresolved acute inflammatory responses or defective immunoregulation of middle inflammation can promote chronic inflammatory processes and stimulate the chronic condition of OME. Cytokines are the central molecular regulators of middle ear inflammation and can switch the acute phase of inflammation in the chronic stage and induce molecular-pathological processes leading to the histopathological changes accompanying OME. In this review we present cytokines identified in otitis media, immunoregulatory [interleukin (IL)-2, IL-10, transforming growth factor-beta]) and allergy associated (IL-4, IL-5, granulocyte-macrophage colony-stimulating factor), as crucial molecular regulators, responsible for chronic inflammation in the middle ear and the chronic condition of OME.
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Affiliation(s)
- Marina G Smirnova
- School of Cell and Molecular Biosciences, University of Newcastle, The Medical School, Framlington Place Newcastle upon Tyne, NE2 4HH, Nottingham, UK.
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Ryan AF, Jung TTK, Juhn SK, Li JD, Andalibi A, Lin J, Bakaletz LO, Post CJ, Ehrlich GD. Recent advances in otitis media. 4C. Interaction between middle ear and inner ear in otitis media. Ann Otol Rhinol Laryngol 2005; 194:56-9. [PMID: 15700936 DOI: 10.1177/00034894051140s108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Allen F Ryan
- Division of Otolaryngology, University of California, San Diego, La Jolla, USA
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Cureoglu S, Schachern PA, Rinaldo A, Tsuprun V, Ferlito A, Paparella MM. Round window membrane and labyrinthine pathological changes: an overview. Acta Otolaryngol 2005; 125:9-15. [PMID: 15799567 DOI: 10.1080/00016480410022534] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The round window membrane is considered the most likely pathway from the middle to the inner ear. Various substances placed in the middle ear have been seen to pass through the round window membrane. Once toxic substances or inflammatory mediators such as cytokines and nitric oxide enter the inner ear, various inner ear sequelae such as labyrinthitis, endolymphatic hydrops, sensorineural hearing loss or more insidious diseases can occur.
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Stenqvist M, Anniko M. Additive effects of toxin exposure and destruction of semicircular canal on cochlear function: an auditory brainstem response study in the rat. Acta Otolaryngol 2004; 124:13-8. [PMID: 14977071 DOI: 10.1080/00016480310000764a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To ascertain whether the severity of toxin-related hearing loss and the interval between instillation of toxin and surgical trauma affect hearing recovery capacity following semicircular canal (SCC) surgery in the rat. MATERIAL AND METHODS Twelve rats were injected with Pseudomonas aeruginosa exotoxin A (PaExoA). Auditory brainstem responses (ABRs) were measured 72 h and 3 weeks later. Depending on the severity of hearing loss, the rats were divided into two groups: those with moderate (Group A; n = 6) and severe (Group B; n = 6) hearing loss. Three rats from Group A were then operated on 3 weeks after toxin exposure and the other three 3 months after instillation of toxin. All Group B rats were operated on after 3 months. RESULTS In Group A, post-surgical hearing loss recovered to a varying degree but rats in Group B showed little or no hearing recovery capacity. This difference was statistically significant. When the six rats with moderately toxin-affected ears were compared, statistical differences in recovery capacity between those operated on at 3 weeks and at 3 months were also detected. The group with a shorter interval showed significantly less hearing recovery of inner ear function following surgical trauma. CONCLUSION When the toxin causes severe hearing damage there is no capacity for cochlear recovery following additional surgical trauma. When the rat inner ear is moderately affected by PaExoA, the interval between toxin exposure and SCC destruction plays a significant role in the ultimate hearing outcome. Cochlear recovery potential seems to be weakened in close temporal proximity to toxin exposure, but recovers with the passage of time.
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Affiliation(s)
- Monika Stenqvist
- Department of Otolaryngology and Head & Neck Surgery, University Hospital (Akademiska Sjukhuset), Uppsala, Sweden.
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Takeuchi N, Anniko M. Dexamethasone modifies the effect of Pseudomonas aeruginosa exotoxin A on hearing. Acta Otolaryngol 2000; 120:363-8. [PMID: 10894410 DOI: 10.1080/000164800750000577] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In the present study, the protective effect of dexamethasone was analysed following exposure of the cochlea to Pseudomonas aeruginosa Exotoxin A (PaExoA). Four groups of albino Sprague-Dawley rats were used. 20 microl saline was instilled through the tympanic membrane into the round window niche (group A, n = 4); 1 microg/20 microl dexamethasone sodium 21-phosphate (dexamethasone) solution was instilled (group B, n = 4); 1 microg/20 microl PaExoA solution was initially instilled followed 1 h later by 20 microl saline (group C, n = 6); and 1 microg/20 microl PaExoA solution was initially instilled followed 1 h later by 1 microg/20 microl dexamethasone solution (group D, n = 6). Frequency-specific (4, 8, 10, 12, 16 and 20 kHz) auditory brainstem responses (ABR) were used to ascertain the threshold prior to exposure and 1, 2, 3, and 5 days and 1 and 2 weeks afterwards. No threshold change was observed in groups A and B, whereas the animals in groups C and D showed some threshold elevation, that in D being smaller than that in C. There was a significant difference at the frequencies 12, 16 and 20 kHz, 2 and 5 days after exposure. The intensity-latency (I-L) curve showed that in group D the cochlear component almost disappeared at high frequency one week after exposure. Our results indicate that dexamethasone can modify the effect of PaExoA caused by non-specific inflammation.
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Affiliation(s)
- N Takeuchi
- Department of Otorhinolaryngology and Head & Neck Surgery, Uppsala University Hospital, Sweden.
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