Otoprotective Effects of Fucoidan Reduce Cisplatin-Induced Ototoxicity in Mouse Cochlear UB/OC-2 Cells.

Cisplatin is a widely used standard chemotherapy for various cancers. However, cisplatin treatment is associated with severe ototoxicity. Fucoidan is a complex sulfated polysaccharide mainly derived from brown seaweeds, and it shows multiple bioactivities such as antimicrobial, anti-inflammatory, anticancer, and antioxidant activities. Despite evidence of the antioxidant effects of fucoidan, research on its otoprotective effects remains limited. Therefore, the present study investigated the otoprotective effects of fucoidan in vitro using the mouse cochlear cell line UB/OC-2 to develop new strategies to attenuate cisplatin-induced ototoxicity. We quantified the cell membrane potential and analyzed regulators and cascade proteins in the apoptotic pathway. Mouse cochlear UB/OC-2 cells were pre-treated with fucoidan before cisplatin exposure. The effects on cochlear hair cell viability, mitochondrial function, and apoptosis-related proteins were determined via flow cytometry, Western blot analysis, and fluorescence staining. Fucoidan treatment reduced cisplatin-induced intracellular reactive oxygen species production, stabilized mitochondrial membrane potential, inhibited mitochondrial dysfunction, and successfully protected hair cells from apoptosis. Furthermore, fucoidan exerted antioxidant effects against oxidative stress by regulating the Nrf2 pathway. Therefore, we suggest that fucoidan may represent a potential therapeutic agent for developing a new otoprotective strategy.

Early Experience of Patients with left Bundle Branch Block Corrected through Left Bundle Branch Area Pacing Compared with Conventional Right Ventricular Pacing: A Single-Center Retrospective Study.

Background: Left bundle branch area pacing (LBBAP) has the advantages of narrow QRS duration, rapid peak left ventricular (LV) activation, and LV dyssynchrony correction with a low, stable pacing output. Here we report our experience with patients undergoing LBBAP with a left bundle branch block (LBBB) for clinically indicated pacemaker or cardiac resynchronization therapy implantation. We compared the initial follow-up data of these patients and patients undergoing conventional right ventricular pacing (RVP). Methods: This retrospective study was performed between January 2017 and December 2020 and recruited 19 consecutive patients (mean age: 63 years; 8 women, 11 men) who underwent LBBAP (13 LBBAP only and 6 LBBAP + LV pacing), and 14 consecutive patients (mean age: 75 years; 8 women, 6 men) who underwent RVP. Demographic data, QRS durations, and echocardiographic parameters were compared before and after the procedures. Results: LBBAP substantially shortened the QRS duration and improved LV dyssynchrony echocardiographic parameters. However, RVP was not significantly associated with prolonged QRS duration and worse LV dyssynchronization. LBBAP improved cardiac contractility in selected patients. We did not find adverse effects of LBBAP on patients with preserved systolic function, possibly due to the limited number of patients and follow-up time. However, two of the 11 patients with preserved systolic function at baseline who underwent conventional RVP developed heart failure after implantation. Conclusions: In our experience, LBBAP improves LBBB-related ventricular dyssynchrony. However, LBBAP requires greater skill, and doubts remain about lead extraction. LBBAP may be an option for patients with LBBB when performed by an experienced operator, however further studies are needed to verify our findings.

Hearing Features and Cochlear Implantation Outcomes in Patients With Pathogenic MYO15A Variants: a Multicenter Observational Study.

OBJECTIVES: Recessive variants in the MYO15A gene constitute an important cause of sensorineural hearing impairment (SNHI). However, the clinical features of MYO15A-related SNHI have not been systemically investigated. This study aimed to delineate the hearing features and outcomes in patients with pathogenic MYO15A variants. DESIGN: This study recruited 40 patients with biallelic MYO15A variants from 31 unrelated families. The patients were grouped based on the presence of N-terminal domain variants (N variants). The longitudinal audiological data and for those undergoing cochlear implantation, the auditory and speech performance with cochlear implants, were ascertained and compared between patients with different genotypes. RESULTS: At the first audiometric examination, 32 patients (80.0%) presented with severe to profound SNHI. Patients with at least one allele of the N variant exhibited significantly better hearing levels than those with biallelic non-N variants (78.2 ± 23.9 dBHL and 94.7 ± 22.8 dBHL, respectively) (p = 0.033). Progressive SNHI was observed in 82.4% of patients with non-profound SNHI, in whom the average progression rate of hearing loss was 6.3 ± 4.8 dBHL/year irrespective of the genotypes. Most of the 25 patients who underwent cochlear implantation exhibited favorable auditory and speech performances post-implantation. CONCLUSIONS: The hearing features of patients with biallelic pathogenic MYO15A variants are characterized by severe to profound SNHI, rapid hearing progression, and favorable outcomes with cochlear implants. Periodic auditory monitoring is warranted for these patients to enable early intervention.

Evaluation of thirty patients with eustachian tube dysfunction in Taiwan by questionnaire survey.

BACKGROUND: Eustachian tube dysfunction (ETD) is a common otolaryngological disorder. The seven-item Eustachian Tube Dysfunction Questionnaire (ETDQ-7) was used for the assessment of symptoms related to ETD and treatment outcome. Currently, there is no traditional Chinese version of the ETDQ-7 to diagnose ETD in Taiwan. We aim to verify the reliability and validity of the traditional Chinese version of the ETDQ-7 in a clinical setting. METHODS: The traditional Chinese version of the ETDQ-7 was completed by 60 adult subjects composed of 30 healthy controls and 30 subjects diagnosed with ETD. The internal consistency was evaluated using the Cronbach's α coefficient. The discriminant validity was calculated by receiver operating characteristic (ROC) curve as an accuracy measure. RESULTS: The overall Cronbach's α coefficient of the traditional Chinese version ETDQ-7 was 0.717. The mean ETDQ-7 total score was 26.97 in the ETD group and 9.27 in the control group. The area under the ROC curve (AUC) was 99.8%, and the sensitivity and specificity of the traditional Chinese ETDQ-7 was 100% and 99.9%, respectively. CONCLUSION: The traditional Chinese version of the ETDQ-7 is a valid and reliable, disease-specific rating scale that can be used to quantitatively evaluate the severity of subjective symptoms of ETD in adult patients.

Otoprotective Effect of 2,3,4',5-Tetrahydroxystilbene-2-O-ß-d-Glucoside on Gentamicin-Induced Apoptosis in Mouse Cochlear UB/OC-2 Cells.

Excessive levels of reactive oxygen species (ROS) lead to mitochondrial damage and apoptotic cell death in gentamicin-induced ototoxicity. 2,3,4',5-Tetrahydroxystilbene-2-O-ß-d-glucoside (THSG), a bioactive constituent, isolated from Polygonum multiflorum Thunb., exhibits numerous biological benefits in treating aging-related diseases by suppressing oxidative damage. However, its protective effect on gentamicin-induced ototoxicity remains unexplored. Therefore, here, we aimed to investigate the otoprotective effect of THSG on gentamicin-induced apoptosis in mouse cochlear UB/OC-2 cells. We evaluated the effect of gentamicin and THSG on the ROS level, superoxide dismutase (SOD) activity, mitochondrial membrane potential, nuclear condensation, and lactate dehydrogenase (LDH) release, and the expression of apoptosis-related proteins was assessed to understand the molecular mechanisms underlying its preventive effects. The findings demonstrated that gentamicin increased ROS generation, LDH release, and promoted apoptotic cell death in UB/OC-2 cells. However, THSG treatment reversed these effects by suppressing ROS production and downregulating the mitochondrial-dependent apoptotic pathway. Additionally, it increased the SOD activity, decreased the expression of apoptosis-related proteins, alleviated the levels of the apoptotic cells, and impaired cytotoxicity. To the best of our knowledge, this is the first study to demonstrate that THSG could be a potential therapeutic option to attenuate gentamicin-induced ototoxicity.

Feasibility of early activation after cochlear implantation.

OBJECTIVES: The purpose of the study is to investigate feasibility of early activation after cochlear implantation by evaluating long-term impedance change and speech perception. DESIGN: Case-control study SETTING: Between July 2015 and December 2016, we prospectively enrolled 20 subjects for early activation (within 24 hours after cochlear implantation). On the other hand, from November 2013 to July 2015, 20 age- and sex-matched control subjects from the database of cochlear implantees treated with conventional activation schedule (4 weeks after surgery) were retrospectively enrolled. PARTICIPANT: Forty patients who underwent cochlear implantation surgeries. MAIN OUTCOME MEASURES: The series impedance and speech perception score of both groups were compared. RESULTS: No statistical difference in long-term follow-up between the two groups was found using GEEs and multivariate analysis. In the early activation group, impedance reached a steady level by the 2nd postoperative week, and the hearing perception ability significantly improved by the 4th postoperative week. CONCLUSION: This comparative study illustrated sequential impedance data during early activation (24 hours) and conventional activation (4 weeks) after CI surgery. There were no major complications in either group, and the safety of early activation with respect to impedance changes, postoperative residual hearing preservation and speech perception scores were non-inferior to that of the conventional group. Therefore, in this study, we established the feasibility of early activation 24 hours after cochlear implantation.

Gestational exposure to polychlorinated biphenyls and dibenzofurans induced asymmetric hearing loss: Yucheng children study.

INTRODUCTION: In 1979, approximately 2000 people in central Taiwan were exposed to polychlorinated biphenyls and dibenzofurans (PCBs/PCDFs) due to ingestion of contaminated rice oil. The children born to mothers exposed to PCBs/PCDFs were called Yucheng children. We conducted a follow-up study to examine the association between gestational PCBs/PCDFS exposure and auditory function in Yucheng children's early adulthood. METHODS: In 1985 and early 1992, Yucheng children and their age, gender, socio-economic matched unexposed referent children were recruited for physical examination and long-term follow-ups. In 2007, Yucheng children and referent children were invited to participate in a health examination, including assessment of pure-tone air-conduction thresholds and distortion product otoacoustic emissions (DPOAEs) test. Gestational exposure to PCBs/PCDFs in Yucheng children were estimated by back-extrapolation of their mother's serum concentration to the time of childbirth. RESULTS: A total of 86 Yucheng children (51.2% males) and 97 referent children (50.5% males) were included for analysis. No difference was found in demographic characteristics between two groups. Among the Yucheng children, 53 had estimated PCBs/PCDFs concentrations. We found that Yucheng children were at higher risk of having elevated hearing threshold at low frequencies in the right ear. Estimated maternal concentrations of 2,3,4,7,8-pnCDF at the time of birth were associated with increased hearing thresholds and decreased DPOAEs amplitudes at low frequencies in the right ear. CONCLUSION: Gestational exposure to PCBs/PCDFs caused adverse asymmetrical hearing effects detectable even in early adulthood.

Impact of Prolonged Door-to-Balloon Times on the Diastolic Function in Acute ST-Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention.

BACKGROUND: Emerging evidence indicates that diastolic left ventricular (LV) function is a powerful outcome predictor after acute ST-elevation myocardial infarction (STEMI). We hypothesized that shorter door-to-balloon (D2B) times with early restoration of coronary perfusion may preserve diastolic LV function in STEMI patients undergoing primary percutaneous coronary intervention (PPCI). METHODS: This study enrolled 340 consecutive STEMI patients who underwent PPCI with D2B times of < 90 min in 232 patients and D2B times ≥ 90 min in 108 patients, who all received subsequent echocardiographic examination within 48 hours of hospitalization. RESULTS: Although the LV ejection fraction was similar (50.92% vs. 51.66%, p = 0.573), the proportion of E/E' ratio > 15 was greater in patients with D2B times ≥ 90 min compared to those with D2B times < 90 min (44.4% vs. 30.6%, p = 0.013). Logistic regression analysis revealed that D2B time ≥ 90 min [odds ratio (OR): 1.82, 95% confidence interval (Cl): 1.04-3.17, p = 0.035] was an independent predictor for LV diastolic dysfunction. The effect was more prominent in patients ≥ 65 years of age (OR: 2.77, 95% CI: 1.09-7.00, p = 0.032), in whom the fraction of LV diastolic dysfunction increased proportionally with prolonged D2B times. CONCLUSIONS: Prolonged D2B time of greater than 90 min predicted LV diastolic dysfunction, particularly in aged subjects. D2B times shortening is important to preserve diastolic heart function after PPCI. KEY WORDS: Acute myocardial infarction; Diastolic dysfunction; Door-to-balloon time; Primary percutaneous coronary intervention.

Prognostic factors of profound idiopathic sudden sensorineural hearing loss.

Profound idiopathic sudden sensorineural hearing loss is thought to have a poor prognosis, but few studies have focused on this condition. We aimed to assess the impact of patient factors, audiologic parameters, and salvage intratympanic steroid injection therapy on the prognosis of profound idiopathic sudden sensorineural hearing loss. The demographic, clinical, and audiologic data, degree of hearing recovery, and efficacy of intratympanic steroid injection therapy in 576 patients with profound idiopathic sudden sensorineural hearing loss (mean age 56.2 ± 14.9 years) who had been admitted at four tertiary referral centers between 2000 and 2011 were retrospectively reviewed. The mean hearing level at the initial presentation was 108.1 ± 9.5 dB. Many patients experienced vertigo (52.1%) and tinnitus (77.4%). At the 2-month follow-up, 172 (29.8%) patients showed some degree of hearing recovery, but only 21 (3.6%) patients recovered normal hearing. Further, the 116 patients who had received salvage intratympanic steroid injections showed a better audiologic outcome (improvement, 26.1 ± 24.3 vs. 15.7 ± 22.1 dB; P = 0.000) than those who had not (n = 429). In conclusion, a higher degree of hearing loss at the initial presentation indicates a poorer prognosis. Salvage intratympanic steroid injection therapy may improve the hearing of patients with profound idiopathic sudden sensorineural hearing loss after the failure of systemic steroid therapy.

Otoprotection against aminoglycoside- and cisplatin-induced ototoxicity focusing on the upstream drug uptake pathway.

Aminoglycoside- and cisplatin-induced ototoxicity, which is a significant issue owing to the widespread use of these drugs in clinical practice, involves the entry of aminoglycosides and cisplatin into the endolymph and hair cells via specific channels or transporters, followed by reactive oxygen species (ROS) generation and hair cells apoptosis. Current strategies focalize primarily on interference with downstream ROS effects; however, recent evidence has demonstrated that inhibiting the uptake of aminoglycosides and cisplatin by hair cells is another promising strategy for tackling the upstream drug uptake pathway. With advances in structural biology, the conformations of certain aminoglycoside and cisplatin channels and transporters, such as the mechanoelectrical transduction channel and organic cation transporter-2, have been largely elucidated. These channels and transporters may become potential targets for the introduction of new otoprotective strategies. This review focuses on the strategies for inhibiting ototoxic drugs uptake by auditory hair cells and provides potential targets for recent developments in the field of otoprotection. Molecular dynamics (MD) simulations of these proteins could help identify the molecules that inhibit the uptake of aminoglycosides and cisplatin by hair cells. Integrating upstream drug uptake pathway targets and MD simulations may help dissect molecular mechanisms and develop novel otoprotective strategies for aminoglycoside- and cisplatin-induced ototoxicity.

Balloon Eustachian Tuboplasty Combined or Not with Myringotomy in Eustachian Tube Dysfunction.

BACKGROUND: Eustachian tube dysfunction (ETD) is a common disorder causing ear pressure, pain, and hearing loss. Balloon Eustachian tuboplasty (BET) is an emerging technique for dilating the Eustachian tube and treating ETD. Whether adding myringotomy improves BET efficacy is controversial. METHODS: This retrospective study included 95 ETD patients undergoing BET alone (n = 44) or BET with myringotomy (BET + M; n = 51) between June 2020 and August 2021 at a single medical center. The primary outcome was the change in ETDQ-7 symptom scores from baseline to 6 months after treatment. Secondary outcomes included audiometry, endoscopy, Valsalva maneuver, and complications. RESULTS: The ETDQ-7 scores improved significantly after treatment in both groups (p < 0.001), without significant between-group differences (p = 0.417). No significant differences occurred in the audiometry, endoscopy, and Valsalva results or in most complications between groups. One BET + M patient had a persistent tympanic membrane perforation. CONCLUSIONS: Both BET alone and BET + M effectively and safely improved the subjective and objective ETD outcomes. However, adding myringotomy did not further improve the outcomes over BET alone, while it incurred risks such as persistent perforation. BET alone may sufficiently treat ETD without requiring myringotomy in this cohort. Further randomized controlled trials should identify optimal candidates for BET alone versus combined approaches.

Correlations between myocardial injury current and lead performance in His bundle pacing compared with left bundle branch area pacing and right ventricular septum pacing.

BACKGROUND: Conduction system pacing by implanting the lead in the His bundle (HBP) region or in the left bundle branch area (LBBAP) has gained popularity. Myocardial injury current (IC) is useful for predicting adequate lead fixation in right ventricular septal pacing (RVSP). OBJECTIVES AND METHODS: We compared the correlations between IC and lead performance among patients receiving HBP (n = 41), LBBAP (n = 53), and historical RVSP (n = 88). LBBAP was an alternative if optimal HBP was not achieved. A positive IC (STpost-screw-in - STpre-screw-in) was defined as > 0.2 mV or a > 25% ST elevation and prolongation of the ventricular electrograms > 10 ms from baseline. RESULTS: HBP patients with a positive IC (48%, 0.84 ± 0.4 V/0.4 ms) exhibited a similar pacing threshold to their LBBAP counterparts (76%, 0.75 ± 0.3 V/0.4 ms, p = 0.329), but a higher pacing threshold than their RVSP counterparts (67%, 0.50 ± 0.1 V/0.4 ms, p < 0.001) at implantation. The R-wave (5.70 ± 3.4 mV) and impedance (660.91 ± 140.8 Ω) were both lower than those of LBBAP (10.35 ± 6.0 mV, p = 0.002; 822.36 ± 235.8 Ω, p = 0.005) and RVSP (11.24 ± 4.9 mV, p < 0.001; 754.27 ± 126.4 Ω, p = 0.006) patients respectively at implantation. The trend of electrical parameter comparisons remained unchanged during follow-up (3.56 ± 1.4 months). Notably, HBP patients without ICs had a higher pacing threshold (1.24 ± 0.6 V/0.4 ms) compared to their LBBAP (0.73 ± 0.3 V/0.4 ms, p = 0.009) and RVSP (0.53 ± 0.1 V/0.4 ms, p < 0.001) counterparts at implantation and during follow-up. CONCLUSIONS: The detection of positive changes of myocardial ICs during HBP was associated with a better capture threshold equivalent to the LBBAP counterpart both at implantation and during short-term follow-up. Further large-scale studies with longer follow-up are necessary to confirm these findings.

The risk factors and quality of life in children with allergic rhinitis in relation to seasonal attack patterns.

A questionnaire survey was conducted to examine whether risk factors and allergic rhinitis (AR)-related quality of life (QOL) were different among children with different seasonal patterns of AR. Participants were students enrolled in elementary and middle schools in Taipei County, Taiwan. Using moving average and principal component analysis, children with current AR were grouped by attack seasons. The effects of personal and environmental factors on AR seasonality were assessed by logistic regression models. AR severity and AR-related QOL were compared within AR seasonal subtypes. Among 4221 children who completed the questionnaire, 1144 and 1605 children were current AR cases and healthy controls, respectively. Four AR subtypes were categorised as follows: perennial, spring, summer/fall, and winter. Age, gender, parental education, maternal passive smoking during pregnancy, breast feeding, and mouldy walls were found to contribute differentially to different AR subtypes. Children suffering from perennial and winter AR were found to have more severe symptoms and significantly lower QOL score compared with other subtypes. Specific personal and environmental risk factors could contribute to different AR seasonal subtypes. Active allergen avoidance and symptomatic treatment should be the focus of management aiming to improve the QOL among children with perennial and winter subtype.

Using multi-stimulus auditory steady state response to predict hearing thresholds in high-risk infants.

The purpose of this study was to investigate whether multi-stimulus auditory steady-state responses were capable of estimating hearing thresholds in high-risk infants. A retrospective chart review study. Three tertiary referral centers. Infants born between January 2004 and December 2006 who met the criteria for risk factors of congenital hearing loss were enrolled in the study. While under sedation, the multi-stimulus auditory steady-state response was used to determine multi-channel auditory steady-state response thresholds for high-risk infants younger than 13 months. Conditioned play audiometry was then applied to these children at 23-48 months of age to obtain pure tone audiograms. Auditory steady-state response thresholds and pure tone thresholds were then compared. A total of 249 high-risk infants were enrolled in the study. 39 infants were lost during follow-up. The remaining 216 infants completed both examinations. The Pearson correlation coefficients (r) between the ASSR levels and pure tone thresholds were 0.88, 0.94, 0.94 and 0.97 at 500, 1,000, 2,000 and 4,000 Hz, respectively. The strength of the relationship between the auditory steady-state responses and pure tone thresholds increased with more severe degrees of hearing loss and higher frequencies. We conclude that initial multichannel ASSR thresholds measured under sedation are highly correlated with pure tone thresholds obtained 2 or 3 years later. ASSR can be used to predict the frequency-specific hearing thresholds of high-risk infants and can provide information for early hearing intervention.

Comparison Benefit between Hydrogen Peroxide and Adrenaline in Tonsillectomy: A Randomized Controlled Study.

This study aimed to further evaluate the benefit of topical hemostasis agents in tonsillectomy. We compared the clinical effects of topical application between hydrogen peroxide and adrenaline in tonsillectomy. Overall, 60 patients (120 tonsils) were prospectively enrolled for tonsillectomy between February 2018 and December 2020. The patients were randomly assigned to either the hydrogen peroxide or adrenaline group. Then, tonsillectomy was performed using hydrogen peroxide as a hemostatic agent on the assigned side, while adrenaline was applied to the other side. All procedures were performed by a surgeon who was blinded to the randomization. The outcome measurements of operation time, intraoperative blood loss, postoperative pain, and hemorrhage events were analyzed. The intraoperative blood loss was significantly lower in the hydrogen peroxide group than in the adrenaline group (9.99 ± 4.51 mL vs. 13.87 ± 6.32 mL; p = 0.0). The median operation time was also significantly lower in the hydrogen peroxide group (8.02 ± 3.59 min vs. 9.22 ± 3.88 min; p = 0.019). Meanwhile, the visual analogue scale (VAS) scores were significantly higher in the hydrogen peroxide group (4.98 ± 1.94 vs. 4.27 ± 1.97; p = 0.001). The topical application of hydrogen peroxide as a hemostatic agent effectively decreases the operation time and intraoperative blood loss. Thus, hydrogen peroxide can be used as a routine hemostatic agent for bleeding control in tonsillectomy.

Worsening Rhinosinusitis as a Prognostic Factor for Patients with Nasopharyngeal Carcinoma: A Retrospective Study.

Rhinosinusitis is common in patients with nasopharyngeal carcinoma (NPC). Our study aimed to explore the role of rhinosinusitis severity in NPC prognosis. Medical records and radiologic examinations of 90 patients with NPC at a single medical center from 2009−2016 were retrospectively analyzed. The Lund−Mackay (L−M) score was obtained for each patient before and after 6 months of treatment. Rhinosinusitis diagnosis was based on L−M scores of ≥4. L−M score differences were calculated as pre-treatment rhinosinusitis (PRRS) minus post-treatment rhinosinusitis (PSRS). L−M score difference was sub-grouped into "L−M scores > 0", "L−M scores = 0", and "L−M scores < 0". Clinical staging of our patients based on the American Joint Committee on Cancer 7th edition were: stage I in nine, stage II in seventeen, stage III in twenty-two, and stage IV in forty-two patients; twenty-seven (30%) patients had died. PRRS incidence was 34.4%, and PSRS was 36.7%. Median of L−M scores difference was 0 (−2.2). L−M score difference was an independent prognostic factor for the overall survival of patients with NPC (p < 0.05). Therefore, worsening rhinosinusitis was a prognostic factor for patients with NPC. Clinicians should consider NPC as a warning sign of poor prognosis during routine follow-ups.

Cochlear implant mapping strategy to solve difficulty in speech recognition.

BACKGROUND: Cochlear implants (CIs) are viable treatment options in patients with severe to profound hearing loss. Speech recognition difficulties were reported in some CI recipients even with a good-aided hearing threshold. The aim of this study was to report a mapping strategy based on different target-aided hearing thresholds to achieve optimal speech recognition and maximize functional outcomes. The safety and efficacy of the mapping strategy were also inspected in the article. METHODS: This prospective repeated measures study enrolled 20 adult CI recipients with postlingual deafness using the MED-EL CI system. Word and sentence discrimination assessment and administration of a questionnaire pertaining to comfort level were conducted at the end of each session. The electrophysiological features of the CI mapping were recorded. RESULTS: The correlation between audiometry results and word and sentence recognition was not high. CIs performed best at an audiometry threshold between 25 and 35 dB. CONCLUSION: CI performance with the best perception relies on a balance between minimizing the hearing threshold and maximizing the dynamic range while maintaining an appropriate comfort level, which was achieved when the target hearing threshold was set at 25-35 dB in this study.

Bisdemethoxycurcumin-mediated Attenuation of Apoptosis Prevents Gentamicin-induced Ototoxicity in Mouse Cochlear UB/OC-2 Cells.

BACKGROUND/AIM: Gentamicin has been widely prescribed since the last two decades despite its ototoxicity and nephrotoxicity. Bisdemethoxycurcumin (BDMC) is an affordable and safe curcuminoid with medicinal properties. We aimed to understand the effects of BDMC on the gentamicin-induced hair cell damage in mouse cochlear UB/OC-2 cells, in order to elucidate the therapeutic potential of BDMC against gentamicin-induced ototoxicity. MATERIALS AND METHODS: We quantified the cell membrane potential and examined the regulators and cascade proteins in the intrinsic pathway of hair cell apoptosis. Mouse cochlear UB/OC-2 cells were treated with BDMC before exposure to gentamicin. The effects of BDMC on hair cell viability, mitochondrial function, and apoptosis-related proteins were examined by flow cytometry, western blot, and fluorescent staining. RESULTS: Our results revealed that BDMC reversed gentamicin-mediated cycle arrest at the G2/M phase, stabilizing the mitochondrial membrane potential, decreasing cleaved caspase proteins, and successfully reversing hair cell apoptosis. CONCLUSION: BDMC is a potential agent for reducing gentamicin-induced ototoxicity.

Ameliorative effect of taxifolin on gentamicin-induced ototoxicity via down-regulation of apoptotic pathways in mouse cochlear UB/OC-2 cells.

BACKGROUND: Taxifolin is a flavanonol with efficacious cytoprotective properties, such as anti-inflammatory, antioxidant, anticancer, hepatoprotective, and nephroprotective effects. However, the potential protective effects of taxifolin against gentamicin-induced ototoxicity have not been confirmed. In this study, the possible mechanisms underlying the effects of taxifolin on gentamicin-induced death of UB/OC-2 cochlear cells were investigated. METHODS: Mouse cochlear UB/OC-2 cells with or without taxifolin pretreatment were exposed to gentamicin, and the effects on cytotoxicity, reactive oxygen species (ROS) production, mitochondrial permeability transition, and apoptotic marker expression were examined using biochemical techniques, flow cytometry, western blotting, and fluorescent staining. RESULTS: Little or no apparent effect of taxifolin on cell viability was observed at concentrations less than 40 µM. Further investigations showed that gentamicin significantly inhibited cell viability in a concentration-dependent manner. Pretreatment with taxifolin attenuated gentamicin-induced lactate dehydrogenase release, as well as cellular cytotoxicity. In addition, taxifolin significantly prevented gentamicin-induced cell damage by decreasing ROS production, stabilizing mitochondrial membrane potential, and downregulating the mitochondrial pathway of apoptosis. CONCLUSION: In summary, pretreatment with taxifolin is effective for mitigating gentamicin-induced apoptotic cell death mediated by the mitochondrial pathway. Our data suggest that taxifolin provides a new approach to combat gentamicin-induced ototoxicity.