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.

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.

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.

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.

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.

2,3,4',5­Tetrahydroxystilbene­2­O­ß­D­glucoside ameliorates gentamicin­induced ototoxicity by modulating autophagy via Sesn2/AMPK/mTOR signaling.

Gentamicin is an important aminoglycoside antibiotic used in the treatment of gram­negative bacterial infections, but nephrotoxicity and ototoxicity reduce its utility. The autophagy pathway is involved in damage of auditory hair cells. With the aim of developing new strategies for attenuating gentamicin ototoxicity, the present study investigated the otoprotective mechanism of 2,3,4',5­tetrahydroxystilbene­2­O­ß­D-glucoside (THSG) in vitro using the mouse cochlear cell line UB/OC­2. MTT assay demonstrated that gentamicin reduced UB/OC­2 cell viability and western blotting showed that gentamicin upregulated autophagy­related proteins, such as Beclin, autophagy related 5 and LC3­II. THSG significantly attenuated gentamicin­induced cytotoxicity, clearly reduced LDH release observed by LDH assay and decreased the expression of autophagy­related proteins. Reverse­transcription­quantitative (RT­q) PCR and western blotting showed that THSG against gentamicin­induced autophagy via suppressing the expression of Sesn2, at both the mRNA and protein level and a possible involvement of AMP­activated protein kinase (AMPK)/mTOR signaling response. Collectively, the present study demonstrated that THSG decreased gentamicin­induced ototoxicity in UB/OC­2 cochlear cells via the autophagic signaling in regulating Sesn2/AMPK/mTOR pathway. These results suggested that THSG might be a new therapeutic agent with the potential to attenuate gentamicin 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.

Treatment of moderate-to-severe otosclerosis with simultaneous piston surgery and incus vibroplasty.

OBJECTIVE: Whereas the nature of otosclerosis has been extensively investigated, treatment modalities in advanced otosclerosis with the sensorineural hearing loss (SNHL) are relatively unexplored. MATERIALS AND METHODS: This article presents a retrospective case series study of nine patients who received a one-stage piston coupled with Vibrant Soundbridge® vibroplasty in treating otosclerosis with moderate-to-severe SNHL. RESULTS: The findings suggest that hearing loss could be restored across frequencies and no significant change in the bone-conduction threshold were measured. CONCLUSION: One-stage piston surgery coupled with incus vibroplasty is a safe procedure and has sufficient efficacy to restore hearing loss in patients with otosclerosis with moderate-to-severe SNHL.

Prognostic factors of unknown primary head and neck squamous cell carcinoma.

OBJECTIVE: To evaluate the prognostic factors of unknown primary head and neck squamous cell carcinoma (HNSCC). STUDY DESIGN: Retrospective study. SUBJECTS: Patients with unknown primary HNSCC from 1980 to 2000 were included. RESULTS: Forty-eight patients, predominantly male and with a mean age of 63.3+/-11.6 years, were recruited. The median survival time (MST) was 44 months. The overall survival rate was 60.4 percent at three years and 39.6 percent at five years. Forty-two patients receiving intervention regimens had a MST of 45 months, while six patients receiving palliative therapy had a MST of 8.5 months (log rank test, P=0.016). With multivariate Cox regression analysis, age (per year), higher nodal stage (N3 vs N1 or N2), and treatment (operation vs nonoperation) had a hazard ratio of 1.081 (P<0.0001), 5.852 (P=0.010), and 0.4 (P=0.042), respectively. CONCLUSION: Older age, higher nodal stage, and palliative treatment indicated poor prognosis. Survival time might be prolonged if surgical treatment is tolerable.

Resected tumours of the sublingual gland: 15 years' experience.

Sublingual gland tumours are rare, and we have evaluated the clinical features and prognosis of patients treated at a tertiary medical centre in eastern Taiwan. We retrospectively reviewed the cases of nine patients with sublingual gland tumours that were resected from December 1993 to November 2008, four of whom were men and five women. The median (range) age at diagnosis was 52 (39-63) years. Seven had malignant tumours, of which adenoid cystic carcinoma was the most common. All patients with malignant tumours had neck dissections, and four had cervical lymph node metastases. The incidence of lymph node metastases was much higher in patients with advanced primary tumours (T1/2 compared with T3/4: one out of three compared with three out of four). All patients with malignant tumours were given adjuvant radiotherapy. There were no local failures. One patient had regional recurrence in the neck and had a successful further resection. Three patients developed distant metastases, and two died during the follow-up period. Our results suggest that radical resection with postoperative radiotherapy offers adequate local and regional control for malignant sublingual gland tumours. Neck dissection is beneficial, especially for T3/4 disease.

Methylation status of insulin-like growth factor-binding protein 7 concurs with the malignance of oral tongue cancer.

BACKGROUND: Aberrant insulin-like growth factor-binding protein 7 (IGFBP-7) expression has been found in various cancers such as prostate, breast, and colon. IGFBP-7 induced the apoptosis of tumor and potentially predicted the clinical outcome in some cancers is further demonstrated. This study investigates the causes and underlying mechanisms of aberrant IGFBP-7 expression in unravelling head and neck squamous cell carcinoma (HNSCC). METHODS: A total of 47 oral tongue cancer patient samples were primarily analyzed for the methylation status in 5' region of IGFBP-7 by methylation-specific PCR (MS-PCR). Subsequently the invasion, overexpression, and knockdown of IGFBP-7 in the HNSCC A253 invasive subpopulation were employed to examine the effect of IGFBP-7. The epithelial-mesenchymal transition (EMT) marker genes and AKT/GSK3ß/ß-catenin signaling were further evaluated by Western blot for the understanding the role of aberrant IGFBP-7 expression and thereof putative mechanism. RESULTS: EMT expressed in the invasive subpopulation of HNSCC cell lines (A253 and RPMI 2650) was contemporary with the down-regulation of IGFBP-7. After treatment with 5-AZA-2' deoxycytidine, the de-methylated CpG sites in the 5' region of IGFBP-7 were observed and IGFBP-7 mRNA expression was also restored. Accordingly, re-expression IGFBP-7 in invasive subpopulation of A253 could induce the mesenchymal-epithelial transition (MET) and concurrently inhibited the cell invasion. Moreover, IGFBP-7 methylation status of 47 oral tongue tumors showed a positive correlation to invasive depth of the tumor, loco-regional recurrence, and cancer sequence. CONCLUSIONS: IGFBP-7 can alter EMT relative marker genes and suppress cell invasion in A253 cell through AKT/GSK3ß/ß-catenin signaling. The epigenetic control of IGFBP-7 in the invasion and metastasis of HNSCC was reported, suggesting that IGFBP-7 could be a prognostic factor for the probability of invasion and a therapeutic remedy.

Comparison of intermittent intratympanic steroid injection and near-continual transtympanic steroid perfusion as salvage treatments for sudden sensorineural hearing loss.

OBJECTIVES/HYPOTHESIS: The purpose of this study was to investigate whether near-continual transtympanic steroid perfusion is more effective than intermittent intratympanic steroid injection as a salvage therapy for idiopathic sudden sensorineural hearing loss. STUDY DESIGN: Case control study. METHODS: We designed a case-control study consisting of 60 patients with sudden sensorineural hearing loss who did not respond well to systemic steroid therapy. From November 2008 to October 2010, we prospectively enrolled subjects for the transtympanic steroid perfusion therapy. We retrospectively collected data from age- and sex-matched patients who had undergone intratympanic steroid injection between January 2003 and October 2008. The audiological results of the two groups were compared. RESULTS: The presalvage pure tone threshold was 65.4 ± 13.5 dB in the transtympanic steroid perfusion group. After the therapy, the hearing threshold was improved by an average of 15.0 ± 9.7 dB, and 53.3% of subjects had improved by 10 dB or more. The speech discrimination score was improved from 12.6% ± 7.0% to 54.4 ± 6.4%. In the intratympanic steroid injection group, the presalvage pure tone threshold was 68.8 ± 16.0 dB. After the therapy, the hearing threshold was improved by an average of 10.7 ± 9.8 dB, and 43.3% of subjects had improved by 10 dB or more. The speech discrimination score was improved from 13.3 ± 6.0% to 46.4 ± 12%. The degree of hearing improvement was significantly greater in the transtympanic group. CONCLUSIONS: Both transtympanic steroid perfusion and intratympanic steroid injection can be used as salvage therapies for idiopathic sudden sensorineural hearing loss. Near-continual transtympanic steroid perfusions may provide better audiological results.

Predictors of locoregional recurrence in early stage oral cavity cancer with free surgical margins.

Locoregional recurrence in patients with early stage oral cavity squamous cell carcinoma (ESOSCC) after surgery remains a problem and can affect their survival. We sought to identify new high-risk factors in these patients, who need further adjuvant therapy. We retrospectively reviewed records for 148 patients who underwent surgery for ESOSCC between 2002 and 2006 with negative surgical margins. The primary endpoint was locoregional recurrence. Recurrence-free survival (RFS) and overall survival (OS) were calculated by the Kaplan-Meier method. Univariate and multivariate analyses were used to identify independent predictors of locoregional recurrence. All patients were grouped into the low- and high-risk groups according to the odds ratios (OR) of the predictors. Recurrence rates of the low- and high-risk groups were then predicted. Recurrence was observed in 17 of 148 (11.5%) patients at the end of this study. None of the patients received postoperative radiotherapy or chemotherapy. At 3 years, the RFS rate was 89.7% and the OS rate at 3 years was 84.1%. Univariate analysis of the RFS revealed three significant prognostic factors: lymphovascular permeation (LVP, p<0.001), perineural infiltration (PNI, p=0.08), and non-T4 muscular invasion (non-T4MI, p<0.005). Multivariate analysis demonstrated that LVP (p=0.007, OR=10.7) and non-T4 MI (p=0.001, OR=8.347) were independent predictors. The recurrence rate was 1.96% in patients without LVP or non-T4MI, and it increased to 26.47% in patients with non-T4MI, to 50% in patients with LVP, and to 50% in patients with both. According to the status of LVP and non-T4MI, patients were divided into two groups: low-risk (no factors present) and high-risk (one or both factors present) groups. The 2-year RFS was lower in the high-risk group (84.13%) than in the low-risk group (93.91%); the 3-year RFS was also lower in the high-risk group (70.49%) than in the low-risk group (91.99%) (p=0.008). Subgroup analysis revealed that elective neck dissections did not affect the outcome or change the pattern of failure. For patients with elective neck dissections, the RFS was lower in the high-risk group than in the low-risk group (p=0.03). In ESOSCC (pT1-2N0), LVP and non-T4MI significantly increased the recurrence rate. The presence of one or both factors (LVP and/or non-T4MI) should be considered as a high-risk condition for locoregional recurrence, and adjuvant therapy is needed in such cases.