Detection of SARS-CoV-2 virus in middle ear effusions and its association with otitis media with effusion.

A large-scale outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) occurred in Shanghai, China, in early December 2022. To study the incidence and characteristics of otitis media with effusion (OME) complicating SARS-CoV-2, we collected 267 middle ear effusion (MEE) samples and 172 nasopharyngeal (NP) swabs from patients. The SARS-CoV-2 virus was detected by RT-PCR targeting. The SARS-CoV-2 virus, angiotensin-converting enzyme 2 (ACE2), and transmembrane serine protease 2 (TMPRSS2) expression in human samples was examined via immunofluorescence. During the COVID-19 epidemic in 2022, the incidence of OME (3%) significantly increased compared to the same period from 2020 to 2022. Ear symptoms in patients with SARS-CoV-2 complicated by OME generally appeared late, even after a negative NP swab, an average of 9.33 ± 6.272 days after COVID-19 infection. The SARS-CoV-2 virus was detected in MEE, which had a higher viral load than NP swabs. The insertion rate of tympanostomy tubes was not significantly higher than in OME patients in 2019-2022. Virus migration led to high viral loads in MEE despite negative NP swabs, indicating that OME lagged behind respiratory infections but had a favorable prognosis. Furthermore, middle ear tissue from adult humans coexpressed the ACE2 receptor for the SARS-CoV-2 virus and the TMPRSS2 cofactors required for virus entry.

A 3D and Explainable Artificial Intelligence Model for Evaluation of Chronic Otitis Media Based on Temporal Bone Computed Tomography: Model Development, Validation, and Clinical Application.

BACKGROUND: Temporal bone computed tomography (CT) helps diagnose chronic otitis media (COM). However, its interpretation requires training and expertise. Artificial intelligence (AI) can help clinicians evaluate COM through CT scans, but existing models lack transparency and may not fully leverage multidimensional diagnostic information. OBJECTIVE: We aimed to develop an explainable AI system based on 3D convolutional neural networks (CNNs) for automatic CT-based evaluation of COM. METHODS: Temporal bone CT scans were retrospectively obtained from patients operated for COM between December 2015 and July 2021 at 2 independent institutes. A region of interest encompassing the middle ear was automatically segmented, and 3D CNNs were subsequently trained to identify pathological ears and cholesteatoma. An ablation study was performed to refine model architecture. Benchmark tests were conducted against a baseline 2D model and 7 clinical experts. Model performance was measured through cross-validation and external validation. Heat maps, generated using Gradient-Weighted Class Activation Mapping, were used to highlight critical decision-making regions. Finally, the AI system was assessed with a prospective cohort to aid clinicians in preoperative COM assessment. RESULTS: Internal and external data sets contained 1661 and 108 patients (3153 and 211 eligible ears), respectively. The 3D model exhibited decent performance with mean areas under the receiver operating characteristic curves of 0.96 (SD 0.01) and 0.93 (SD 0.01), and mean accuracies of 0.878 (SD 0.017) and 0.843 (SD 0.015), respectively, for detecting pathological ears on the 2 data sets. Similar outcomes were observed for cholesteatoma identification (mean area under the receiver operating characteristic curve 0.85, SD 0.03 and 0.83, SD 0.05; mean accuracies 0.783, SD 0.04 and 0.813, SD 0.033, respectively). The proposed 3D model achieved a commendable balance between performance and network size relative to alternative models. It significantly outperformed the 2D approach in detecting COM (P≤.05) and exhibited a substantial gain in identifying cholesteatoma (P<.001). The model also demonstrated superior diagnostic capabilities over resident fellows and the attending otologist (P<.05), rivaling all senior clinicians in both tasks. The generated heat maps properly highlighted the middle ear and mastoid regions, aligning with human knowledge in interpreting temporal bone CT. The resulting AI system achieved an accuracy of 81.8% in generating preoperative diagnoses for 121 patients and contributed to clinical decision-making in 90.1% cases. CONCLUSIONS: We present a 3D CNN model trained to detect pathological changes and identify cholesteatoma via temporal bone CT scans. In both tasks, this model significantly outperforms the baseline 2D approach, achieving levels comparable with or surpassing those of human experts. The model also exhibits decent generalizability and enhanced comprehensibility. This AI system facilitates automatic COM assessment and shows promising viability in real-world clinical settings. These findings underscore AI's potential as a valuable aid for clinicians in COM evaluation. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2000036300; https://www.chictr.org.cn/showprojEN.html?proj=58685.

Simultaneous gentamicin-mediated damage and Atoh1 overexpression promotes hair cell regeneration in the neonatal mouse utricle.

Loss of hair cells from vestibular epithelium results in balance dysfunction. The current therapeutic regimen for vestibular diseases is limited. Upon injury or Atoh1 overexpression, hair cell replacement occurs rapidly in the mammalian utricle, suggesting a promising approach to induce vestibular hair cell regeneration. In this study, we applied simultaneous gentamicin-mediated hair cell ablation and Atoh1 overexpression to induce neonatal utricular hair cell formation in vitro. We confirmed that type I hair cells were the primary targets of gentamicin. Furthermore, injury and Atoh1 overexpression promoted hair cell regeneration in a timely and efficient manner through robust viral transfection. Hair cells regenerated with type II characteristics in the striola and type I/II characteristics in non-sensory regions. Rare EdU+/myosin7a+ cells in sensory regions and robust EdU+/myosin7a+ signals in ectopic regions indicate that transdifferentiation of supporting cells in situ, and mitosis and differentiation of non-sensory epithelial cells in ectopic regions, are sources of regenerative hair cells. Distinct regeneration patterns in in situ and ectopic regions suggested robust plasticity of vestibular non-sensory epithelium, generating more developed hair cell subtypes and thus providing a promising stem cell-like source of hair cells. These findings suggest that simultaneously causing injury and overexpressing Atoh1 promotes hair cell regeneration efficacy and maturity, thus expanding the understanding of ectopic plasticity in neonatal vestibular organs.

Hair cell uptake of gentamicin in the developing mouse utricle.

Intratympanic injection of gentamicin has proven to be an effective therapy for intractable vestibular dysfunction. However, most studies to date have focused on the cochlea, so little is known about the distribution and uptake of gentamicin by the counterpart of the auditory system, specifically vestibular hair cells (HCs). Here, with a combination of in vivo and in vitro approaches, we used a gentamicin-Texas Red (GTTR) conjugate to investigate the mechanisms of gentamicin vestibulotoxicity in the developing mammalian utricular HCs. In vivo, GTTR fluorescence was concentrated in the apical cytoplasm and the cellular membrane of neonatal utricular HCs, but scarce in the nucleus of HCs and supporting cells. Quantitative analysis showed the GTTR uptake by striolar HCs was significantly higher than that in the extrastriola. In addition, the GTTR fluorescence intensity in the striola was increased gradually from 1 to 8 days, peaking at 8-9 days postnatally. In vitro, utricle explants were incubated with GTTR and candidate uptake conduits, including mechanotransduction (MET) channels and endocytosis in the HC, were inhibited separately. GTTR uptake by HCs could be inhibited by quinine, a blocker of MET channels, under both normal and stressed conditions. Meanwhile, endocytic inhibition only reduced GTTR uptake in the CoCl2 hypoxia model. In sum, the maturation of MET channels mediated uptake of GTTR into vestibular HCs. Under stressed conditions, MET channels play a pronounced role, manifested by channel-dependent stress enhanced GTTR permeation, while endocytosis participates in GTTR entry in a more selective manner.

Canonical Wnt Signaling Pathway on Polarity Formation of Utricle Hair Cells.

As part of the inner ear, the vestibular system is responsible for sense of balance, which consists of three semicircular canals, the utricle, and the saccule. Increasing evidence has indicated that the noncanonical Wnt/PCP signaling pathway plays a significant role in the development of the polarity of the inner ear. However, the role of canonical Wnt signaling in the polarity of the vestibule is still not completely clear. In this study, we found that canonical Wnt pathway-related genes are expressed in the early stage of development of the utricle and change dynamically. We conditionally knocked out ß-catenin, a canonical Wnt signaling core protein, and found that the cilia orientation of hair cells was disordered with reduced number of hair cells in the utricle. Moreover, regulating the canonical Wnt pathway (Licl and IWP2) in vitro also affected hair cell polarity and indicated that Axin2 may be important in this process. In conclusion, our results not only confirm that the regulation of canonical Wnt signaling affects the number of hair cells in the utricle but also provide evidence for its role in polarity development.

Sound localization, speech and tone recognition for stimuli presented from the rear in bilateral cochlear implant users.

OBJECTIVE: To assess any differences in spatial listening ability of cochlear implant recipients when using both or only one of two bilateral cochlear implants (BCIs) for stimuli originating from behind the subject. DESIGN: Twelve loudspeakers were placed in the rear horizontal plane of the subjects to test the sound localisation performance of BCI users and normal-hearing listeners (NHLs) with or without interfering noise. Stimuli were presented via two rear loudspeakers simultaneously during the speech recognition test. In the tone recognition test, another anechoic chamber was used with stimuli presenting from a loudspeaker behind the participants. STUDY SAMPLE: Twenty-seven NHLs and eleven BCI users. RESULTS: Average root-mean-square (RMS) error for the bilateral condition was significantly lower than that for the right and left cochlear implant (CI) conditions with or without interfering noises (p < 0.05). Average speech or tone recognition scores for the bilateral condition and the right and left CI conditions were not statistically significant (p > 0.05). CONCLUSION: Sound localisation with BCIs was significantly more accurate than with either implant alone. Speech and tone recognition scores were not better with two compared to those of one activated implant. Given the small number of subjects, the results should be considered as preliminary.

The transcriptome characteristics of vestibular organs from delayed endolymphatic hydrops patients (Meniere's disease).

OBJECTIVES: To identify genes that are related to delayed endolymphatic hydrops (DEH) in patients by RNA-Seq analysis. DESIGN: Observational study. SETTING: Eye & ENT Hospital, Fudan University (Shanghai, China). PARTICIPANTS: We collected the entire vestibular system from four patients with DEH who underwent labyrinthectomy. Three control samples were collected from patients with acoustic neuroma or facial neuroma treated via the translabyrinthine approach. High-throughput RNA-Seq analysis was performed to investigate gene expression in the pathological vestibular system. MAIN OUTCOME MEASURES: Our bioinformatic analysis identified 17 genes that were upregulated and eight genes that were downregulated in patients with DEH compared with the controls. RESULTS: The altered gene expression profile suggested that DEH is closely related to neuropathy and autoimmune disease. In addition, many of the differentially regulated genes were involved in cell adhesion, suggesting a role of cell adhesion in DEH. Immunofluorescence analysis confirmed the expression of PMP2 and CLDN19 in the cytoplasm of hair cells and scattered expression of MPZ at cell junctions. The protein expression levels were higher in specimens from patients with Ménière's disease and DEH compared with controls. CONCLUSIONS: The protein expression profile of vestibular organs in patients with endolymphatic hydrops exhibited a degree of similarity to that of Ménière's disease. Endolymphatic hydrops is characterised by autoimmune abnormalities. DEH and Ménière's disease are likely to be different manifestations of the same disease, with disparate clinical symptoms. RNA-Seq is a useful analytical tool to characterise the vestibular pathology based on its transcriptome.

A Predictive Model Development of Hospital Admission during Triage in a Chinese Ear, Nose, and Throat Emergency Department.

INTRODUCTION: Triaging patients into correct severity categories in an emergency department is an advanced skill that depends on a quick assessment after obtaining very little information. The purpose of this study was to assess specific risk factors associated with hospital admissions in the emergency department environment of the specialized Eye, Ear, Nose, and Throat hospital located in Shanghai, China. METHODS: This study was a retrospective cohort study. Patients visiting the emergency department in a tertiary hospital in eastern China from February 2008 to August 2015 were included. Univariate and multivariate analyses were used to identify the risk factors related to hospital admissions. Combining variables calculated from the regression equation of multivariate analysis (binary logistic regression analysis) enabled the risk factors quantification. The receiver operating characteristic analysis was used to identify the most informative cutoff point of the combining predictors. RESULTS: A total of 188715 patients were enrolled in the study. Of them, 8395 patients (4.4%) required hospital admission. Hour of visit, season, age, sex, chief complaint, anatomical location, and locale of patients were independent risk factors of hospital admission by univariate and multivariate analysis. Combining predictors were calculated from the equation of the multivariate logistic model. The area under the curve of the combining predictors was 0.949, and the 95% confidence interval was 0.947 to 0.951 (P <.001), with a sensitivity of 95.2% and a specificity of 85.6%. A cutoff score of less than -35.1975 was associated with hospital admission. DISCUSSION: This study provided a method to build a feasible predictive model of hospital admission during triage. Understanding risk factors is an important part of the triage process in order to correctly assign priorities to the patients served. The outcomes of this study would add additional information for the triage nurse to consider in assessing the patient and assigning acuity ratings. The model developed here requires validation in future research.

Deep Learning in Automated Region Proposal and Diagnosis of Chronic Otitis Media Based on Computed Tomography.

OBJECTIVES: The purpose of this study was to develop a deep-learning framework for the diagnosis of chronic otitis media (COM) based on temporal bone computed tomography (CT) scans. DESIGN: A total of 562 COM patients with 672 temporal bone CT scans of both ears were included. The final dataset consisted of 1147 ears, and each of them was assigned with a ground truth label from one of the 3 conditions: normal, chronic suppurative otitis media, and cholesteatoma. A random selection of 85% dataset (n = 975) was used for training and validation. The framework contained two deep-learning networks with distinct functions: a region proposal network for extracting regions of interest from 2-dimensional CT slices; and a classification network for diagnosis of COM based on the extracted regions. The performance of this framework was evaluated on the remaining 15% dataset (n = 172) and compared with that of 6 clinical experts who read the same CT images only. The panel included 2 otologists, 3 otolaryngologists, and 1 radiologist. RESULTS: The area under the receiver operating characteristic curve of the artificial intelligence model in classifying COM versus normal was 0.92, with sensitivity (83.3%) and specificity (91.4%) exceeding the averages of clinical experts (81.1% and 88.8%, respectively). In a 3-class classification task, this network had higher overall accuracy (76.7% versus 73.8%), higher recall rates in identifying chronic suppurative otitis media (75% versus 70%) and cholesteatoma (76% versus 53%) cases, and superior consistency in duplicated cases (100% versus 81%) compared with clinical experts. CONCLUSIONS: This article presented a deep-learning framework that automatically extracted the region of interest from two-dimensional temporal bone CT slices and made diagnosis of COM. The performance of this model was comparable and, in some cases, superior to that of clinical experts. These results implied a promising prospect for clinical application of artificial intelligence in the diagnosis of COM based on CT images.

Developmental and Functional Hair Cell-Like Cells Induced by Atoh1 Overexpression in the Adult Mammalian Cochlea In Vitro.

Hair cells (HCs) in the mammalian cochleae cannot spontaneously regenerate once damaged, resulting in permanent hearing loss. It has been shown that Atoh1 overexpression induces hair cell-like cells (HCLCs) in the cochlea of newborn rodents, but this is hard to achieve in adult mammals. In this study, we used a three-dimensional cochlear culture system and an adenoviral-mediated delivery vector to overexpress Atoh1 in adult mouse cochleae. HCLCs were successfully induced from 3 days after virus infection (3 DVI) in vitro, and the number increased with time. HCLCs were myosin7a positive and distinguishable from remnant HCs in a culture environment. Meanwhile, patch-clamp results showed that noninactive outward potassium currents (sustained outward potassium currents) could be recorded in HCLCs and that their magnitude increased with time, similar to normal HCs. Furthermore, transient HCN currents were recorded in some HCLCs, indicating that the HCLCs experienced a developmental stage similar to normal HCs. We also compared the electrophysiological features of HCLCs from adult mice with native HCs and found the HCLCs gradually matured, similar to the normal HCs. Meanwhile, HCLCs from adult mice possessed the same bundles as developmental HCs. However, these HCLCs did not express prestin, which is a special marker for outer hair cells (OHCs), even at 13 DVI. These results demonstrate that Atoh1 overexpression induces HCLC formation in the adult mammalian cochlea and that these HCLCs were functional and experienced a developmental process similar to that of normal HCs.

Concurrent Occurrence of Congenital Ossicular Anomaly and Localized Cholesteatoma: Series of 10 Cases.

OBJECTIVE: The objective of this study is to describe the clinical features, managements and outcomes of a rare coexistence of congenital ossicular anomaly and localized cholesteatoma. A literature review on these cases and each congenital disorder is also presented. METHODS: A retrospective chart review was performed on patients diagnosed with congenital ossicular anomaly with concurrent localized cholesteatoma from 2008 to 2017. Clinical data of these patients were collected. RESULTS: A total of 10 patients were identified. All patients presented with unilateral hearing loss. Pure-tone audiometry showed conductive hearing loss in all affected ears with an average air conduction (AC) threshold of 59 dB. High-resolution computed tomography scans of the temporal bone diagnosed ossicular anomaly for 90% (9/10); however, only 50% (5/10) had a diagnosis of localized cholesteatoma. A transcanal exploratory tympanotomy under the microscope was performed to discover whether the localized tiny-sized cholesteatoma around the ossicular chain did not have direct contact with the ossicular chain, which could be diagnosed as congenital cholesteatoma. We removed the localized cholesteatoma and reconstructed the ossicular chain in each patient. All localized cholesteatomas were found in the posterior-superior quadrant of the middle ear. Ossicular chain anomalies were associated with the incus and/or the stapes in all cases. Hearing improvement was achieved in each of the 6 patients who were followed up postoperatively, with an average AC threshold of 35 dB. The clinical features of congenital ossicular anomaly with concurrent congenital cholesteatoma were compared with those of each congenital disorder. The pathogenesis of each condition was also discussed. CONCLUSIONS: Congenital ossicular anomaly with concurrent congenital cholesteatoma is rare. It shares similar clinical features with congenital ossicular anomaly occurring alone, therefore awareness should be raised for a possible concurrent congenital cholesteatoma which was easy to miss in the diagnosis (50%) by the radiologist. A patient's hearing level can be improved by removal of the cholesteatoma and reconstruction of the ossicular chain. Localized cholesteatoma does not usually show residuals or recurrence.

Titanium ossicular chain reconstruction in single stage canal wall down tympanoplasty for chronic otitis media with mucosa defect.

PURPOSE: To evaluate surgical outcomes for chronic otitis media with mucosa defect underwent titanium ossicular chain reconstruction (OCR) in single stage canal wall down tympanoplasty (CWD). METHODS: A clinical retrospective study was performed on 83 cases of the chronic otitis media with mucosa defect and 123 ears with mucosa integrity according to intraoperative findings that underwent synchronous titanium OCR in single stage CWD form January 2012 to January 2018. Pre- and postoperative air conduction threshold (AC), air-bone gap (ABG) and ABG closure at 0.5, 1, 2, and 4 kHz were investigated. RESULTS: The overall mean AC threshold of 53.4 ±â€¯16.5 dB was lowered to 41.2 ±â€¯15.9 dB postoperatively (p < 0.01). The mean pre- and postoperative ABG of all patients were 27.9 ±â€¯9.9 dB and 17.2 ±â€¯9.3 dB (p < 0.01), respectively, with a mean ABG closure of 10.7 ±â€¯8.4 dB. The total rate of success, postoperative ABG ≤ 20 dB was achieved in 71.4%. In the mucosa defect group underwent TORP, the mean pre- and postoperative ABG were 28.1 ±â€¯9.8 dB and 20.1 ±â€¯9.0 dB (p < 0.01), respectively, with the ABG closure was 8.0 ±â€¯7.9 dB. In the mucosa defect group underwent PORP, the mean pre- and postoperative ABG were 27.9 ±â€¯10.1 dB and 16.5 ±â€¯9.1 dB (p < 0.01), respectively, with the ABG closure was 11.4 ±â€¯8.6 dB. Furthermore, in the mucosa defect group, there was significant difference in success rate of achieved postoperative ABG ≤ 20 dB between the TORP (48.9%) and PORP (77.5%) (p < 0.05). CONCLUSION: It is revealed PORP in single stage CWD tympanoplasty for the patients suffered from chronic otitis media with mucosa defect is favored.

Endoscopic Tympanoplasty without Mastoidectomy for Active Mucosal Chronic Otitis Media with Mastoid and Tympanic Antrum Lesions: A Prospective Clinical Study.

OBJECTIVE: This study aims to assess the effectiveness of endoscopic tympanoplasty without mastoidectomy in the management of active mucosal chronic otitis media (COM) patients with mastoid and tympanic antrum lesions. METHODS: It is a prospective controlled study where 42 patients with active mucosal COM with mastoid and tympanic antrum lesions or normal aeration were recruited from the outpatient clinic of the otology department, Eye Ear Nose and Throat Hospital of Fudan University. All patients underwent endoscopic tympanoplasty without mastoidectomy by using the underlay technique with tragal cartilage graft with one side-perichondrium. The follow-up period was at least 3 months and results were evaluated in terms of graft uptake, ear dryness and hearing improvement. RESULTS: Statistics showed no significant difference in graft uptake between the mastoid and tympanic antrum lesions group (90.5%) and the normal aeration group (95.2%). There was no significant difference in ear dryness between the mastoid and tympanic antrum lesions group (95.2%) and the normal aeration group (100%). Hearing improvement was comparable in the 2 groups. CONCLUSION: Regardless of the occurrence of soft density shadows in temporal bone showed by high-resolution computerized tomography in the mastoid and tympanic antrum, mastoidectomy is an unnecessary procedure for dealing with active mucosal COM without cholesteatoma. Therefore, this study shows that endoscopic tympanoplasty without mastoidectomy may be applied to active mucosal COM without cholesteatoma.

Mimic Cochlear Implant Surgery-Induced Cochlear Infection Fails to Further Damage Auditory Pathway in Deafened Guinea Pigs.

BACKGROUND Kanamycin and subsequent furosemide administration was applied to the healthy guinea pigs to induce deafness. MATERIAL AND METHODS Of the deafened guinea pigs, 10 were further infused with anti-infection procedures (Group B) and the other 10 animals did not undergo anti-infection procedures (Group C). In Group B, the deafened animals were able to restore cochlear and middle ear functions following the anti-infection procedure. In Group C, all animals developed cochlear and middle ear infections. RESULTS Compared to the healthy guinea pigs, hair cells and spiral ganglion neurons (SGN) of deafened animals (in Group B and Group C) were severely damaged. SGN density of deafened animals was significantly lower than that of healthy control animals in all ear turns except the basal turn. There was no significant difference between Group B and Group C in SGN density. The average optical density value of neurofilaments of deafened animals was also significantly decreased after the ototoxic drug administration. Notably, the density of the neurons in the cochlear nucleus region (CNR) of the brainstem were not significantly different between the healthy control guinea pigs and deafened animals. CONCLUSIONS Mimic cochlear implant surgery-induced cochlear infection caused no significant damage to the auditory pathway in ototoxic drug-induced deafened guinea pigs.

Mechanisms of Hearing Loss in a Guinea Pig Model of Superior Semicircular Canal Dehiscence.

Defective acoustic transmission in the cochlea is closely related with various auditory and vestibular symptoms. Among them, semicircular canal dehiscence (SCD) with a defective semicircular bone is typical. Currently, the pathogenesis of SCD is usually explained by the third window hypothesis; however, this hypothesis fails to explain the variability in the symptoms and signs experienced by superior SCD (SSCD) patients. We evaluated the mechanism of hearing loss in a guinea pig model of bony dehiscence with various sizes and locations along the superior semicircular canal. Auditory brainstem responses (ABRs) and laser Doppler velocimetry were used to measure hearing loss and vibration changes before and after fenestration, as well as after restorative patching. ABR thresholds at low frequencies (e.g., 1000 Hz) increased after fenestration and decreased back to the normal range after we repaired the defect. Energy leakage from the surgically introduced third window was detected in the range of 300-1500 Hz, accompanied by increased vibration at the umbo, stapes head, and the dehiscence site, while decreased vibration was observed at the round window membrane in the same frequency range. After the patching procedure, the deviant vibrations were recovered. The degree of postfenestration energy leakage was proportional to the size of fenestration and the proximity of the fenestration site to the oval window. These results suggest that the bony fenestration of the superior semicircular canal mimics the hearing loss pattern of patients with SSCD. The decrease in perilymph wave impedance likely accounts for the auditory changes.

Therapeutic value of nerve growth factor in promoting neural stem cell survival and differentiation and protecting against neuronal hearing loss.

Nerve growth factor (NGF) is a neurotrophic factor that modulates survival and differentiation of neural stem cells (NSCs). We investigated the function of NGF in promoting growth and neuronal differentiation of NSCs isolated from mouse cochlear tissue, as well as its protective properties against gentamicin (GMC) ototoxicity. NSCs were isolated from the cochlea of mice and cultured in vitro. Effect of NGF on survival, neurosphere formation, and differentiation of the NSCs, as well as neurite outgrowth and neural excitability in the subsequent in vitro neuronal network, was examined. Mechanotransduction capacity of intact cochlea and auditory brainstem response (ABR) threshold in mice were also measured following GMC treatment to evaluate protection using NGF against GMC-induced neuronal hearing loss. NGF improved survival, neurosphere formation, and neuronal differentiation of mouse cochlear NSCs in vitro, as well as promoted neurite outgrowth and neural excitability in the NSC-differentiated neuronal culture. In addition, NGF protected mechanotransduction capacity and restored ABR threshold in gentamicin ototoxicity mouse model. Our study supports a potential therapeutic value of NGF in promoting proliferation and differentiation of NSCs into functional neurons in vitro, supporting its protective role in the treatment of neuronal hearing loss.

Analysis of the Damage Mechanism Related to CO2 Laser Cochleostomy on Guinea Pig Cochlea.

Different types of lasers have been used in inner ear surgery. Therefore, it is of the utmost importance to avoid damage to the inner ear (e.g., hyperthermia and acoustic effects) caused by the use of such lasers. The aim of this study was to use a high powered fibre-enabled CO2 laser (10 W, 606 J/cm2) to perform cochleostomies on guinea pig cochlea and to investigate the possible laser-induced damage mechanisms. The temperature changes in the round window membrane, auditory evoked brainstem response, and morphological of the hair cells were measured and recorded before and after laser application. All of the outcomes differed in comparison with the control group. A rise in temperature and subsequent increased hearing loss were observed in animals that underwent surgery with a 10 W CO2 laser. These findings correlated with increased injury to the cochlear ultrastructure and a higher positive expression of E-cadherin and ß-catenin in the damaged organ of Corti. We assume that enhanced cell-cell adhesion and the activated ß-catenin-related canonical Wnt-signalling pathway may play a role in the protection of the cochlea to prevent further damage.

Effect of Endolymphatic Hydrops on Sound Transmission in Live Guinea Pigs Measured with a Laser Doppler Vibrometer.

Objective. This study aimed at describing the mechanism of hearing loss in low frequency and the different dynamic behavior of the umbo, the stapes head, and the round window membrane (RWM) between normal guinea pigs and those with endolymphatic hydrops (EH), using a laser Doppler vibrometer (LDV). Methods. Cochlear sections were stained with hematoxylin and eosin (HE) to evaluate the hydropic ratio (HR). Auditory brainstem responses (ABR) and whole-mount immunostaining were measured. Displacement of the umbo, stapes head, and RWM in response to ear-canal sound was evaluated using a LDV. Results. Mean HR values in EH model of all the turns are larger than the control group. The ABR threshold of the EH group was significantly higher than that of the control. Strong positive correlation was found between HR at apical turn and ABR threshold elevation at 1000 Hz and at subapical turn and ABR threshold elevation at 2000 Hz. FITC-phalloidin immunostaining of the cochlear basilar membrane in the apical, subapical, and suprabasal turns showed missing and derangement stereocilia of third-row outer hair cells. The umbo, stapes head, and RWM displacement in ears with EH was generally lower than that of normal ears. The EH-induced differences in stapes head and RWM motion were significant at 0.5 kHz. Conclusion. The LDV results suggested that the higher inner ear impedance in EH affected the dynamic behavior of the two opening windows of the cochlea and then reduced the vibration of the ossicular chain by increasing the afterload, resulting in acoustic dysfunction. The vibration reduction mainly occurred at low frequencies, which has related with the morphology changes of the apical and subapical turns in EH model.

Comparative Study on the Roles of the Number of Accelerations and Rotation Angle in the Treatment Maneuvers for Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo.

AIMS: This study aims to investigate the roles of the number of accelerations and rotation angle in the treatment of posterior semicircular canal benign paroxysmal positional vertigo (PC-BPPV). METHODS: We enrolled 344 patients with unilateral PC-BPPV. Of these, 167 patients in the simple-step maneuver (SSM) group were accelerated twice and rotated 120° per step, whereas 177 patients in the multi-step maneuver (MSM) group were accelerated 4 times and rotated 60° per step. Dix-Hallpike (DH) tests were performed to categorize the treatment outcome as follows: 'symptom free' if the result was negative, 'symptom persistent' if the result remained positive after performing the maneuver 3 times or 'canal conversion' if horizontal nystagmus was evoked. RESULTS: Of the patients in the SSM and MSM groups, 78.4 and 91.5% became symptom free, respectively, while canal conversion occurred in 13.8 and 5.1%, respectively (p = 0.003, χ(2) test). The success rate after performing the maneuver once was 57.1% in the MSM and 32.3% in the SSM symptom-free patients (p = 0.001, χ(2) test). One month after the treatment, 22.0 and 9.6% of the SSM and MSM patients had symptom relapse, respectively (p = 0.007, χ(2) test). CONCLUSIONS: More accelerations and a smaller rotation angle improved the effectiveness and efficiency of the repositioning maneuvers and reduced canal conversion.

Ankrd6 is a mammalian functional homolog of Drosophila planar cell polarity gene diego and regulates coordinated cellular orientation in the mouse inner ear.

The coordinated polarization of neighboring cells within the plane of the tissue, known as planar cell polarity (PCP), is a recurring theme in biology. It is required for numerous developmental processes for the form and function of many tissues and organs across species. The genetic pathway regulating PCP was first discovered in Drosophila, and an analogous but distinct pathway is emerging in vertebrates. It consists of membrane protein complexes known as core PCP proteins that are conserved across species. Here we report that the over-expression of the murine Ankrd6 (mAnkrd6) gene that shares homology with Drosophila core PCP gene diego causes a typical PCP phenotype in Drosophila, and mAnkrd6 can rescue the loss of function of diego in Drosophila. In mice, mAnkrd6 protein is asymmetrically localized in cells of the inner ear sensory organs, characteristic of components of conserved core PCP complexes. The loss of mAnkrd6 causes PCP defects in the inner ear sensory organs. Moreover, canonical Wnt signaling is significantly increased in mouse embryonic fibroblasts from mAnkrd6 knockout mice in comparison to wild type controls. Together, these results indicated that mAnkrd6 is a functional homolog of the Drosophila diego gene for mammalian PCP regulation and act to suppress canonical Wnt signaling.