Ryotaro Omichi

Time Courses of Changes in Phospho- and Total- MAP Kinases in the Cochlea after Intense Noise Exposure

Mitogen-activated protein kinases (MAP kinases) are intracellular signaling kinases activated by phosphorylation in response to a variety of extracellular stimuli. Mammalian MAP kinase pathways are composed of three major pathways: MEK1 (mitogen-activated protein kinase kinase 1)/ERK 1/2 (extracellular signal-regulated kinases 1/2)/p90 RSK (p90 ribosomal S6 kinase), JNK (c-Jun amino (N)-terminal kinase)/c-Jun, and p38 MAPK pathways. These pathways coordinately mediate physiological processes such as cell survival, protein synthesis, cell proliferation, growth, migration, and apoptosis. The involvement of MAP kinase in noise-induced hearing loss (NIHL) has been implicated in the cochlea; however, it is unknown how expression levels of MAP kinase change after the onset of NIHL and whether they are regulated by transient phosphorylation or protein synthesis. CBA/J mice were exposed to 120-dB octave band noise for 2 h. Auditory brainstem response confirmed a component of temporary threshold shift within 0–24 h and significant permanent threshold shift at 14 days after noise exposure. Levels and localizations of phospho- and total- MEK1/ERK1/2/p90 RSK, JNK/c-Jun, and p38 MAPK were comprehensively analyzed by the Bio-Plex® Suspension Array System and immunohistochemistry at 0, 3, 6, 12, 24 and 48 h after noise exposure. The phospho-MEK1/ERK1/2/p90 RSK signaling pathway was activated in the spiral ligament and the sensory and supporting cells of the organ of Corti, with peaks at 3–6 h and independently of regulations of total-MEK1/ERK1/2/p90 RSK. The expression of phospho-JNK and p38 MAPK showed late upregulation in spiral neurons at 48 h, in addition to early upregulations with peaks at 3 h after noise trauma. Phospho-p38 MAPK activation was dependent on upregulation of total-p38 MAPK. At present, comprehensive data on MAP kinase expression provide significant insight into understanding the molecular mechanism of NIHL, and for developing therapeutic models for acute sensorineural hearing loss.

Cochlear implantation is a therapeutic option for superficial siderosis patients with sensorineural hearing loss

BACKGROUND Superficial siderosis is a rare disease that results from chronic bleeding in the subarachnoid space. Haemosiderin deposits throughout the subpial layers of the brain and spinal cord lead to progressive sensorineural hearing loss, which is seen in 95 per cent of patients with superficial siderosis. The impact of cochlear implantation on the quality of life of superficial siderosis patients is under debate. CASE REPORT A 38-year-old male with superficial siderosis presented with bilateral progressive sensorineural hearing loss. The patient underwent cochlear implantation and his quality of life was improved as evaluated by the Abbreviated Profile of Hearing Aid Benefit inventory. CONCLUSION The remarkable improvement in Abbreviated Profile of Hearing Aid Benefit scores shown in this study indicates that cochlear implantation leads to a better quality of life in superficial siderosis patients.

Regulatory effect of TLR3 signaling on staphylococcal enterotoxin-induced IL-5, IL-13, IL-17A and IFN-γ production in chronic rhinosinusitis with nasal polyps

BACKGROUND Toll-like receptor 3 (TLR3) is expressed in upper airways, however, little is known regarding whether Toll-like receptor 3 (TLR3) signals exert a regulatory effect on the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP), especially on eosinophilic inflammation. We sought to investigate the effect of Poly(IC), the ligand for TLR3, on cytokine production by dispersed nasal polyp cells (DNPCs). METHODS DNPCs were pretreated with or without Poly(IC), and were then cultured in the presence or absence of staphylococcal enterotoxin B (SEB), following which the levels of IL-5, IL-10, IL-13, IL-17A and interferon (IFN)-γ in the supernatant were measured. To determine the involvement of IL-10 and cyclooxygenase in Poly(IC)-mediated signaling, DNPCs were treated with anti-IL-10 monoclonal antibody and diclofenac, the cyclooxygenase inhibitor, respectively. Poly(IC)-induced prostaglandin E2 (PGE2) production was also determined. RESULTS Exposure to Poly(IC) induced a significant production of IL-10, but not of IL-5, IL-13, IL-17A or IFN-γ by DNPCs. Pretreatment with Poly(IC) dose-dependently inhibited SEB-induced IL-5, IL-13 and IL-17A, but not IFN-γ production. Neutralization of IL-10 significantly abrogated the inhibitory effect of Poly(IC). Treatment with diclofenac also abrogated the inhibitory effect of Poly(IC) on SEB-induced IL-5 and IL-13 production. However, unlike exposure of diclofenac-treated DNPCs to lipopolysaccharide, the ligand for TLR4, exposure of these cells to Poly(IC) did not enhance IL-5 or IL-13 production. Poly(IC) did not significantly increase PGE2 production by DNPCs. CONCLUSIONS These results suggest that TLR3 signaling regulates eosinophilia-associated cytokine production in CRSwNP, at least in part, via IL-10 production.

Impact of early intervention on comprehensive language and academic achievement in Japanese hearing-impaired children with cochlear implants

OBJECTIVES Early hearing detection and intervention (EHDI) is critical for achievement of age-appropriate speech perception and language development in hearing-impaired children. It has been 15 years since newborn hearing screening (NHS) was introduced in Japan, and its effectiveness for language development in hearing-impaired children has been extensively studied. Moreover, after over 20 years of cochlear implantation in Japan, many of the prelingual cochlear implant (CI) users have reached school age, and the effect of CI on language development have also been assessed. To identify prognostic factors for language development, audiological/language test scores and demographic factors were compared among prelingual severe-to-profound hearing-impaired children with CI divided into subgroups according to age at first hearing aid (HA) use and whether they received NHS. METHODS Prelingual severe-to-profound deafened children from the Research on Sensory and Communicative Disorders (RSCD) project who met the inclusion criteria were divided into groups according to the age (in months) of HA commencement (before 6 months: group A, after 7 months: group B), and the presence or absence of NHS (groups C and D). Language development and socio-economic data were obtained from audiological/language tests and a questionnaire completed by caregivers, respectively. RESULTS In total, 210 children from the RSCD project participated in this study. Group A (n=49) showed significantly higher scores on comprehensive vocabulary and academic achievement (p<0.05) than group B (n=161), with no difference in demographics except for significantly older age in group B. No differences in language scores were observed between group C (n=71) and group D (n=129), although participants of group D was significantly older and had used CIs longer (p<0.05). CONCLUSIONS Early use of HAs until the CI operation may result in better language perception and academic achievement among CI users with prelingual deafness. A long-term follow-up is required to assess the usefulness of NHS for language development.

Transcanal endoscopic ear surgery for perilymphatic fistula after electric acoustic stimulation

Transcanal endoscopic ear surgery (TEES) will become a very useful therapeutic option. A perilymphatic fistula (PLF) is defined as sudden sensorineural hearing loss and/or vertigo caused by leakage of the perilymph through a fistula from the oval window and/or round window. We report a case of PLF after electric acoustic stimulation (EAS), a kind of cochlear implant, successfully treated by TEES. A 38-year-old man presented to our hospital with vertigo and hearing loss (HL). His vertigo was induced by Valsalva maneuvers. Eight months ago, he underwent EAS for his right ear for congenital sensorineural HL. Although he maintained his hearing level after EAS, his pure tone audiogram this time showed deterioration of hearing at low frequencies in his right ear. A diagnosis of right PLF was made. After confirming the non-effectiveness of oral prednisolone treatment, PLF repair surgery to patch the oval and round windows by TEES was performed. His vertigo did not recur after the surgery. To the best of our knowledge, this is the first report of PLF repair surgery by TEES without a microscope. The wide-field view of the middle ear by TEES was useful to prevent electrode damage in a PLF patient with a cochlear implant.

Evaluation of a New and Simple Classification for Endoscopic Sinus Surgery

Objective In 2013, the Japanese Rhinologic Society proposed a simple classification for endoscopic sinus surgery (ESS). This classification consists of five procedures (type I, fenestration of the ostiomeatal complex, with uncinectomy and widening of the natural ostium; type II, single-sinus procedure, with manipulating the inside of the sinus; type III, polysinus procedure; type IV, pansinus procedure; type V, extended procedure beyond the sinus wall). The clinical relevance of this classification in chronic rhinosinusitis (CRS) and paranasal sinus cyst was evaluated. Study Design A retrospective validation study. Methods A total of 122 patients (195 sinuses) who underwent ESS in Okayama University Hospital in 2012 were enrolled. The relationships between the ESS classification and the clinical course, including the operation time, bleeding amounts during surgery and postoperative changes of olfaction, the computed tomography (CT) score, and nasal airway resistance were analyzed. Results A total of 195 ESS procedures were classified into type I (n = 3), type II (n = 17), type III (n = 91), type IV (n = 82), and type V (n = 2). The major phenotypes of type II, III, and IV ESS were paranasal sinus cyst (68%), CRS without nasal polyps (77%), and CRS with nasal polyps (55%), respectively, and the difference was significant. The degree of ESS based on this classification was positively and significantly correlated with the operation time and bleeding amounts. As a whole, olfaction, CT score, and nasal airway resistance were significantly improved after surgery. The degree of improvement was similar between type III and type IV ESS. Conclusion This simple classification for ESS reflected the perioperative burden of the disease.

Pediatric central auditory processing disorder showing elevated threshold on pure tone audiogram

Central auditory processing disorder (CAPD) is a condition in which dysfunction in the central auditory system causes difficulty in listening to conversations, particularly under noisy conditions, despite normal peripheral auditory function. Central auditory testing is generally performed in patients with normal hearing on the pure tone audiogram (PTA). This report shows that diagnosis of CAPD is possible even in the presence of an elevated threshold on the PTA, provided that the normal function of the peripheral auditory pathway was verified by distortion product otoacoustic emission (DPOAE), auditory brainstem response (ABR), and auditory steady state response (ASSR). Three pediatric cases (9- and 10-year-old girls and an 8-year-old boy) of CAPD with elevated thresholds on PTAs are presented. The chief complaint was difficulty in listening to conversations. PTA showed elevated thresholds, but the responses and thresholds for DPOAE, ABR, and ASSR were normal, showing that peripheral auditory function was normal. Significant findings of central auditory testing such as dichotic speech tests, time compression of speech signals, and binaural interaction tests confirmed the diagnosis of CAPD. These threshold shifts in PTA may provide a new concept of a clinical symptom due to central auditory dysfunction in CAPD.

Characteristics of audiogram configuration in multiple-system atrophy C and cortical cerebellar atrophy.

Abstract Conclusion: The prevalence of low-tone hearing loss (LTHL) is significantly high in spinocerebellar degeneration (SCD) with cerebellar predominance, including multiple-system atrophy C (MSA-C) and cortical cerebellar atrophy (CCA). Objective: This study aimed to test the hypothesis that SCD with cerebellar predominance, MSA-C and CCA may cause auditory symptoms. Methods: The shape and threshold of pure-tone audiograms were evaluated for MSA-C (n = 47; mean (± SD) age, 61.6 ± 8.9 years), CCA (n = 16; 62.8 ± 9.5 years), and age-matched controls (n = 169; 62.5 ± 10.7 years). To differentiate specific hearing loss for MSA-C and CCA from presbycusis, the shape of audiograms was examined based on previously established audiological criteria. Results: When audiogram shape was defined according to audiological criteria, the odds ratio for LTHL in SCD compared to controls was 2.492 (95% confidence interval (CI) = 1.208–5.139; p < 0.05, Pearson’s Chi-square test) in MSA-C and 2.194 (95% CI = 0.709–6.795) in CCA. When the selection of audiogram shape according to these criteria was verified by three certified audiologists, odds ratios for LTHL in MSA-C and CCA were 3.243 (95% CI = 1.320–7.969) and 3.692 (95% CI = 1.052–12.957), respectively, significantly higher than in controls.

Outcomes of consonant-vowel monosyllable perception and word recognition after cochlear implantation in elderly Japanese patients

Abstract Conclusion: Performance in consonant-vowel (CV) monosyllable speech perception after cochlear implantation (CI) in the elderly (≥ 65 years) is equivalent to that of young adults (18–64 years). Present data in the Japanese language supported the indication for CI in the elderly. Word recognition after CI was significantly lower in the elderly than young adults. Objective: This study compared outcomes of monosyllable perception and word recognition after CI between elderly patients and young adults with post-lingual deafness. Age-related differences in CV monosyllable speech perception in Japanese were examined. Methods: A retrospective chart review of 137 patients with post-lingual deafness who underwent CI at Okayama University Hospital during 1992–2014 [young adults aged 18–64 years (n = 96) and elderly aged ≥ 65 years (n = 41) at implantation] was conducted. CV monosyllable speech perception post-CI was compared among age groups (18–29, 30–39, 40–49, 50–59, 60–69, 70–79, 80–89). CV monosyllable perception and word recognition scores post-CI were compared between the elderly and young adults. Results: There was no significant difference in CV monosyllable speech perception among age groups. CV monosyllable speech perception in the elderly (61.4 ± 25.5%) did not differ from that of young adults (65.9 ± 24.8%). Word recognition scores were significantly lower in the elderly (64.3 ± 28.1%) than young adults (80.4 ± 25.9%) (p < 0.05).