The efficacy and safety of systemic injection of Ginkgo biloba extract, EGb761, in idiopathic sudden sensorineural hearing loss: a randomized placebo-controlled clinical trial

The Placebo Effect on Tinnitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To quantify the placebo effect in randomized clinical trials treating tinnitus with oral or intratympanic placebo treatment.

DATA SOURCES

CINAHL, PubMed, and Scopus were searched for articles from conception to October 2022. MESH and key terms such as "tinnitus," "placebo," and "medication" were used to find randomized, placebo-controlled trials. The search was limited to articles in English.

METHODS

Randomized controlled trials with adult subjects evaluating tinnitus pretreatment and posttreatment with an oral or intratympanic medication versus a placebo arm were included. Crossover studies, studies involving middle/inner ear operations or devices, and studies that exclusively included nonidiopathic etiologies of tinnitus were excluded. Mean tinnitus symptom survey scores for the Tinnitus Handicap Inventory (THI), Tinnitus Severity Index, Tinnitus Functional Index, Tinnitus Handicap Questionnaire, and Visual Analog Scales for tinnitus Intensity/Loudness (VAS-L), Annoyance (VAS-An), and Awareness (VAS-Aw) were extracted for both placebo and experimental groups.

RESULTS

953 studies were screened with 23 studies being included in the final analysis. Meta-analysis of mean difference (MD) was calculated using RevMan 5.4. MD between pretreatment and posttreatment THI scores of the placebo arms was 5.6 (95% confidence interval, 3.3-8.0; p < 0.001). MD between pretreatment and posttreatment VAS scores of the placebo groups for Loudness, Annoyance, and Awareness were 0.8 (0.0 to 1.6, p = 0.05), 0.2 (-0.2 to 0.5, p = 0.34), and 0.3 (-0.0 to 0.7, p = 0.08), respectively.

CONCLUSIONS

Placebo treatment has shown effectiveness in improving patient-reported evaluations of tinnitus when using some standardized metrics such as THI and VAS-L; however, the improvement is not as substantial as nonplacebo treatment.

The construction and validation of prognostic prediction model for sudden sensorineural hearing loss in middle-aged and elderly people

OBJECTIVE

Idiopathic sudden sensorineural hearing loss (ISSNHL), as an otologic emergency, is commonly encountered and its prevalence has been climbing every year recently. To our knowledge, the prognosis of middle-aged and elderly patients is worse than that of young patients. Previous researches mainly focused on the adult population, which was considered as prognostic models who performed hearing recovery in ISSNHL. However, few studies regarding the middle-aged and elderly population who are regarded as prognostic models have been reported. Therefore, we aim to construct and validate a nomogram-based prognostic prediction model, which can provide a reference for the prognostic assessment in the middle-aged and elderly patients with ISSNHL.

METHOD

A total of 371 middle-aged and elderly ISSNHL patients who were admitted to the Department of Otolaryngology-Head and Neck Surgery, Yanbian Hospital, Yanbian University, from April 2018 to April 2023 were enrolled in the study. All subjects were randomly divided into two groups including training group (n = 263) and validation group (n = 108). Lasso regression and multi-factor logistic regression were jointly utilized to screen out prognosis-related independent risk factors and establish a nomogram-based risk prediction model. The accuracy and clinical application value of the model were evaluated by combining the Bootstrapping method and k-fold cross-validation, plotting the receiver operating characteristic  (ROC)  curve, calculating the area under the ROC curve (AUC), plotting the decision curve analysis (DCA), and the calibrating curve.

RESULT

We used the method of lasso regression combined with multivariate logistic regression and finally screened out eight predictors (including age, number of affected ears, degree of hearing loss, type of hearing curve, duration of disease, presence of vertigo, diabetes, and lacunar cerebral infarction) that were included into the nomogram. The C-index were 0.823 [95% CI (0.725, 0.921)] and 0.851 [95% CI (0.701, 1.000)], and the AUC values were 0.812 and 0.823 for the training and validation groups, respectively. The calibration curve for the validation group was approximately conformed to that for the modeling group, indicating favorable model calibration. The DCA results revealed the modeling group (3%-86%) and the validation group (2%-92%) showed significant net clinical benefit under the majority of thresholds.

CONCLUSION

This study developed and validated a nomogram-based prognostic prediction model which based on the eight independent risk factors mentioned above. The predictors are conveniently accessible and may assist clinicians in formulating individualized treatment strategies.

Exploring Audiologic Outcomes in Sudden Sensorineural Hearing Loss: A Retrospective Analysis

Objective This retrospective study aims to present the audiologic outcomes of patients aged 18 years and above who underwent treatment for sudden sensorineural hearing loss (SSNHL) at the tertiary Hospital Central Sur Petróleos Mexicanos in Mexico City, Mexico, between January 2000 and December 2015. Main outcome measures The main outcome measures were patient demographics (age, sex, comorbidities) time from symptom onset to diagnosis and treatment initiation, initial threshold, treatment details (type, dosage, duration), adverse effects, audiometry at diagnosis and at the end of treatment, follow-up duration, and pure-tone average. Results A total of 72 patients were included, with a mean follow-up duration of four months. Comorbidities such as type 2 diabetes mellitus, hypertension, and hypertriglyceridemia were observed in a significant portion of patients. However, these conditions and the use of salvage therapy and adjuvant drugs did not impact hearing recovery. A longer delay from symptom onset to medical attention was associated with a lower gain in decibels (p=0.307). Diabetic patients who received steroid treatment showed a significant gain of at least 15 dB, indicating the greatest benefit in this subgroup. Conclusions Adjuvant drugs may be unnecessary and ineffective in treating SSNHL. Metabolic disorders may be linked to the development of SSNHL. Steroid treatment is the only effective therapeutic option for improving hearing recovery in diabetic patients. Early initiation of treatment after symptom onset is crucial for maximizing auditory recovery.

Contemporary Review of Idiopathic Sudden Sensorineural Hearing Loss: Management and Prognosis

Sudden sensorineural hearing loss (SSNHL) is a rapid decline in auditory function that needs urgent medical management. Although etiologic factors, including viral infections, autoimmune diseases, and vascular issues, contribute to the understanding of SSNHL, the condition remains unclear in most cases. Systemic steroids are often used as the first-line treatment because they reduce inner ear inflammation; however, there remains numerous discussions about the effectiveness of alternative treatments. To predict hearing recovery is crucial in patients' counseling with factors, including delayed treatment, vertigo, and other health conditions, which indicate poor prognosis. Herein, we review contemporary research on the treatment approaches and outcome predictions of SSNHL to establish important guidelines for physicians in evaluating and treating patients with SSNHL.

Age-related hearing loss and its potential drug candidates: a systematic review

BACKGROUND

Age-related hearing loss (ARHL) is one of the main illnesses afflicting the aged population and has a significant negative impact on society, economy, and health. However, there is presently no appropriate therapeutic treatment of ARHL due to the absence of comprehensive trials.

OBJECTIVES

The goal of this review is to systematically evaluate and analyze recent statistics on the pathologic classifications, risk factors, treatment strategies, and drug candidates of ARHL, including that from traditional Chinese medicine (TCM), to provide potential new approaches for preventing and treating ARHL.

METHODS

Literature related to ARHL was conducted in databases such as PubMed, WOS, China National Knowledge Infrastructure (CNKI), and Wanfang from the establishment of the database to Jan, 2023. The pathology, causal factor, pathophysiological mechanism, treatment strategy, and the drug candidate of ARHL were extracted and pooled for synthesis.

RESULTS

Many hypotheses about the etiology of ARHL are based on genetic and environmental elements. Most of the current research on the pathology of ARHL focuses on oxidative damage, mitochondrial dysfunction, inflammation, cochlear blood flow, ion homeostasis, etc. In TCM, herbs belonging to the kidney, lung, and liver meridians exhibit good hearing protection. Seven herbs belonging to the kidney meridian, 9 belonging to the lung meridian, and 4 belonging to the liver meridian were ultimately retrieved in this review, such as Polygonum multiflorum Thunb., Panax ginseng C.A. Mey, and Pueraria lobata (Willd.) Ohwi. Their active compounds, 2,3,4',5-Tetrahydroxystilbene-2-O-D-glucoside, ginsenoside Rb1, and puerarin, may act as the molecular substance for their anti-ARHL efficacy, and show anti-oxidative, neuroprotective, anti-inflammatory, anti-apoptotic, or mitochondrial protective effects.

CONCLUSION

Anti-oxidants, modulators of mitochondrial function, anti-inflammation agents, vasodilators, K+ channel openers, Ca2+ channel blockers, JNK inhibitors, and nerve growth factors/neurotrophic factors all contribute to hearing protection, and herbs are an important source of potential anti-ARHL drugs.

Migrainous Vertigo, Tinnitus, and Ear Symptoms and Alternatives

Migraine headaches frequently coexist with vestibular symptoms such as vertigo, motion sickness, and gait instability. Migraine-related vasospasm can also damage the inner ear, which results in symptoms such as sudden sensorineural hearing loss and resultant tinnitus. The pathophysiology of these symptoms is not yet fully understood, and despite their prevalence, there is no universally approved management. This review summarizes the data on complementary and integrative medicine in treating patients with migrainous ear disorders.

Better late than never: initial experience of intra-arterial pulsed-urokinase-injection as a salvage therapy for refractory sudden sensorineural hearing loss

BACKGROUND AND PURPOSE

Cochlear vascular micro-thrombosis has been hypothesized as one of the pathogenic mechanisms for sudden sensorineural hearing loss (SSNHL) refractory to regular management. This study aimed to evaluate the feasibility and safety of intra-arterial pulsed-injection urokinase (IAPU) as a salvage therapy for SSNHL after the failure of conventional therapy.

METHODS

We retrospectively reviewed our patient database to identify refractory SSNHL patients between November 2017 and July 2020. Study outcomes before and after the IAPU therapy were compared between IAPU and conventional therapy groups.

RESULTS

Sixty-seven moderate-profound SSNHL patients (29 in IAUP group, 38 in control group) were included in this study. Compared to the control group, patients in the IAPU group showed more significant improvement in pure tone average (PTA) (34.2 ± 23.5 vs. 10.7 ± 13.1, p < 0.001) and degree of hearing recovery (total: 20.7% vs. 5.3%, partial: 24.1% vs. 10.5%, mild: 27.6% vs. 13.2% and non: 27.6% vs. 71.1%) 2 weeks after admission. In the IAPU group, a significant improvement of PTA (86.6 ± 11.5 vs. 54.6 ± 20.1 dB, p < 0.005) was observed on the first day after IAPU treatment.

CONCLUSION

In carefully selected SSNHL cases with a highly suspected vascular origin, IAPU is a safe and effective therapy when conventional treatments have failed. Despite the encouraging findings of our work, large studies are needed to better investigate the strengths and limitations of this salvage therapy.

Efficacy of Ginkgo biloba Extract Combined with Hormones in the Treatment of Sudden Deafness and Its Effect on the Reactivity of Peripheral Blood T Cell Subsets

This work was aimed at exploring the efficacy of Ginkgo biloba extract combined with hormones in the treatment of sudden deafness and the influence on the reactivity of peripheral blood T cell subsets (PBTCSs). In this work, 64 patients with sudden deafness who were treated in The First Affiliated Hospital of Hunan University of Traditional Chinese Medicine from August 2019 to August 2022 were selected as the research objects. The patients were randomly divided into a hormone group (treatment with prednisone acetate, n = 34) and a combination group (treatment with Ginkgo-Damole combined with prednisone acetate, n = 30). After the two groups of patients were treated in different ways, their efficacy, symptom improvement, changes in blood rheology, and PBTCSs were compared. The total effective rates (TERs) of the hormone group and the combination group were 76.32% and 95.73%, respectively (P < 0.05). The fibrinogen contents of the patients in the combination group were obviously lower than those in the hormone group after 5 d, 7 d, and 10 d of treatment (P < 0.05). The high blood viscosity (HBV) values of patients in the combination group at 5 d, 7 d, and 10 d after treatment were greatly lower than those in the hormone group (P < 0.05). The low blood viscosity (LBV) values after 3 d, 7 d, and 10 d of treatment in the combined group were much lower in contrast to those in the hormone group (P < 0.05). The CD3+, CD4+, and CD4+/CD8+ in peripheral blood in the combination group were sharply higher while the CD8+ in the combined group was lower in contrast to the hormone group (P < 0.05). There was no visible difference in the incidence of adverse reactions between the two groups of patients after treatment (P > 0.05). In conclusion, the combined application of Ginkgo biloba extract and hormones could effectively improve the abnormal hemorheological indexes of patients with sudden deafness and effectively relieve the imbalance of PBTCSs, which was safe.

Medical Therapy of Hearing Impairment and Tinnitus with Chinese Medicine: An Overview

The current review gives a comprehensive overview of the recent development in Chinese medicine (CM) for treating several kinds of acquired nerve deafness and tinnitus, as well as links the traditional principle to well-established pharmacological mechanisms for future research. To date, about 24 herbal species and 40 related ingredients used in CM to treat hearing loss and tinnitus are reported for the treatment of endocochlear potential, endolymph growth, lowering toxic and provocative substance aggregation, inhibiting sensory cell death, and retaining sensory transfer. However, there are a few herbal species that can be used for medicinal purposes. Nevertheless, clinical studies have been hampered by a limited population sample, a deficiency of a suitable control research group, or contradictory results. Enhanced cochlear blood flow, antiinflammatory antioxidant, neuroprotective effects, and anti-apoptotic, as well as multi-target approach on different auditory sections of the inner ear, are all possible benefits of CM medications. There are numerous unknown natural products for aural ailment and tinnitus identified in CM that are expected to be examined in the future utilizing various aural ailment models and processes.

Efficacy and safety of standardized Ginkgo biloba L. leaves extract as an adjuvant therapy for sudden sensorineural hearing loss: A systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. has been used for medical purposes in China for centuries. Standardized Ginkgo biloba L. leaves extract (GBE) is a widely used botanical drug which displays a variety of pharmacological effects against sudden sensorineural hearing loss (SSNHL).

AIM OF THE STUDY

To evaluate the efficacy and safety of GBE as an adjuvant therapy, administered with corticosteroids, for the initial management of patients with SSNHL.

MATERIALS AND METHODS

We searched seven databases for randomized clinical trials (RCTs) comparing GBE plus corticosteroids with corticosteroids alone for SSNHL treatment. Data analysis was carried out by Review Manager 5.4 and Stata 16.0 software. The study was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. We subsequently evaluated the certainty of evidence using the GRADE (Grading of Recommendation Assessment, Development and Evaluation) approach.

RESULTS

A total of 11 RCTs involving 1069 patients were included. Meta-analysis indicated that the clinical cure rate (RR = 1.33, 95% CI = 1.12 to 1.58, P = 0.001) and total effective rate (RR = 1.24, 95%CI = 1.17 to 1.31, P < 0.001) in SSNHL patients receiving GBE plus corticosteroids was superior to patients receiving corticosteroids alone. After treatment, pure tone average (PTA) improvement of observation group was better than that in the control group (WMD = 10.33, 95%CI = 6.46 to 14.21, P < 0.001). The levels of whole blood high shear viscosity (WMD = 0.93, 95%CI = 0.28 to 1.59, P = 0.005), whole blood medium shear viscosity (WMD = 0.53, 95%CI = 0.11 to 0.95, P = 0.01), whole blood low shear viscosity (WMD = 1.26, 95%CI = 0.80 to 1.72, P < 0.001), plasma viscosity (WMD = 0.19, 95%CI = 0.09 to 0.30, P < 0.001) and fibrinogen (WMD = 0.80, 95%CI = 0.25 to 1.35, P = 0.004) were lower than those in the control group. There was no significant difference in the change of hematokrit between two groups (WMD = 4.23, 95%CI = -0.54 to 8.99, P = 0.08). GBE was generally well tolerated, and there was no significant difference in the incidence of adverse reactions between two groups (RR = 1.01, 95%CI = 0.57 to 1.79, P = 0.97).

CONCLUSION

The results of the current study suggested that GBE might be effective and promising as an adjuvant to corticosteroids in the initial treatment of moderate to profound SSNHL. However, the GRADE assessment indicated that the overall strength of evidence was not high. Further studies with high methodological quality and low risk of bias are needed to confirm the positive results. PROSPERO registration No. CRD 42020190113.

Comparison between postauricular steroid injection and intratympanic steroid perfusion for refractory severe and profound sudden sensorineural hearing loss

BACKGROUND

To analyze the clinical efficacy of intratympanic steroid perfusion (ISP) and postauricular steroid injection (PSI) for refractory severe and profound sudden sensorineural hearing loss (SSNHL).

METHODS

SSNHL patients who failed a conventional treatment with severe to profound hearing loss [pure tone average (PTA, 0.25-8 kHz) > 60 dB] were treated with ISP or PSI plus antioxidant and neurotrophin for 10 consecutive days. Antioxidant and neurotrophin were administrated either intravenously and/or orally. All patients were assigned into the ISP group or the PSI group and followed up for more than three months. The changes in PTA, effective rate and side effects were analyzed in the two groups.

RESULTS

Similar hearing improvements and effective rates were observed in the two groups. However, a slightly better efficacy was observed in the PSI group compared to the ISP group. Patients with shorter intervals from onset to treatment had significantly more hearing improvements. The route of antioxidant and neurotrophin administration had no impact on treatment effects.

CONCLUSION

Both ISP and PSI could be used as salvage treatments for refractory SSNHL. These salvage treatments should be started as soon as possible once SSNHL patients fail a conventional treatment.

Evaluation and comparison of the efficacy of long-acting betamethasone and dexamethasone as injections in the treatment of idiopathic sudden hearing loss

INTRODUCTION & OBJECTIVE

The aim of the present study was to determine the efficacy of long-acting betamethasone, and its comparison with Dexamethasone as an intratympanic injection in the treatment of Sudden Sensorineural Hearing Loss (SSNHL).

MATERIALS AND METHODS

Thirty-one patients who do not respond to systemic steroids and poor prognosis patients were enrolled in this study. The patients divided randomly into two groups: 1- Dexamethasone and 2- Long acting betamethasone. Dexamethasone (0.4 ml/mg) or long-acting betamethasone (0.1 ml/mg) was slowly injected (0.4 to 0.6 cc) into the superior-anterior area of the tympanic membrane as 6 injections twice a week for a total of 3 weeks. Right after the treatment and one, two and six months after completion of treatment, an audiometry was performed and compared with the pre-injection values.

RESULTS

Speech Reception Threshold (SRT) showed improvements in both groups immediately after treatment and in the follow-up period, compared to baseline. Speech Discrimination Score (SDS) also improved in both groups directly after treatment and at one-month follow-up. The hearing improvement in the Dexamethasone group was clinically better than in the Beta group, but due to the non-parametric data, it was not possible to analyze the hearing improvement process in the variable group.

CONCLUSION

According to the results obtained in this study, intratympanic corticosteroid injection in the treatment of patients with SSNHL has positive and promising results on improving hearing level.

Sudden sensorineural hearing loss during pregnancy: etiology, treatment, and outcome

OBJECTIVE

To analyze the etiologies, treatments, and outcomes of sensorineural hearing loss (SSNHL) during pregnancy.

STUDY DESIGN

Retrospective chart review of 25 pregnant patients treated for SSNHL between January 2012 and September 2019. Forty-nine age matched non-pregnant women with severe and profound hearing loss diagnosed with SSNHL during the same period served as controls. Data were recorded on age, symptoms, onset of hearing loss, audiometric results, treatments, and outcomes.

RESULTS

The mean age was 29.6 years (range 23-38 years). Intratympanic steroids (ITS) were administered in 15 (60.0%) pregnant women with SSNHL. Three women were treated with postauricular steroids only, while another woman was treated with intravenous ginkgo leaf extract and dipyridamole. The remaining six women received no medications. More than half (8/15, 53.3%) of pregnant women with SSNHL receiving ITS experienced hearing improvement. Pregnant women with profound hearing loss who received no medication had no hearing improvement. Most pregnant women with SSNHL (12/15, 80.0%) had higher fibrinogen levels than controls (mean values 3.77±0.71 g/L and 2.54±0.48 g/L, respectively).

CONCLUSION

Fibrinogen could be a risk factor for SSNHL during pregnancy. ITS may benefit pregnant women with severe and profound SSNHL.

Effectiveness of Ginkgo biloba diterpene lactone in the treatment of sudden sensorineural hearing loss

PURPOSE

To evaluate the effectiveness of systemic Ginkgo biloba diterpene lactone therapy for sudden sensorineural hearing loss.

METHODS

This retrospective review investigated 56 patients with unilateral sudden sensorineural hearing loss. Among them, 26 patients received conventional therapy (group C, intravenous methylprednisolone), and 30 received conventional therapy supplemented with Ginkgo biloba diterpene lactone (group G). Pure tone audiometry was measured before treatment and 1 month after treatment. The average pure tone audiometry gain, pure tone audiometry gain at each frequency, pure tone audiometry gain according to initial hearing loss, and rate of effectiveness were defined as functionally relevant recovery of hearing and compared between the two groups.

RESULTS

The average pure tone audiometry gain was significantly greater in group G (20.6 ± 15.1 dB) than in group C (11.9 ± 13.3 dB) (p = 0.025), with similar trends at 250, 1 k, and 8 k Hz. In the subgroup of patients with profound hearing loss (initial pure tone audiometry >70 dB), hearing gain was significantly higher in group G (26.7 ± 14.4 dB) than in C (5.5 ± 9.0 dB) (p = 0.034). In the mild-moderate hearing loss subgroup (initial pure tone audiometry ≤70 dB), the pure tone audiometry gain did not differ significantly (group G: 18.4 ± 14.3 dB; group C: 13.0 ± 13.4 dB) (p = 0.209). The overall rate of effectiveness was 73.3% and 57.7% in groups G and C, respectively; however, the difference was statistically insignificant (p = 0.218).

CONCLUSIONS

Compared with conventional therapy alone, supplementary systemic administration of Ginkgo biloba diterpene lactone to treat sudden sensorineural hearing loss could improve hearing recovery, especially, in patients with profound hearing loss.

Correlation between serum lipid and prognosis of idiopathic sudden sensorineural hearing loss: a prospective cohort study

BACKGROUND

To investigate the correlation between blood lipids and the prognosis of idiopathic sudden sensorineural hearing loss (ISSNHL).

METHODS

We included 232 patients with ISSNHL at the Second Affiliated Hospital of Shanghai University from June 2015 to March 2017 using a prospective cohort study design. We collected information including age, gender, hypertension, diabetes, mellitus, vertigo, as well as the levels of blood total cholesterol (TC), triglycerides (TG), and low-density lipoproteins (LDL-C). We also recorded the ratio between the levels of low-density lipoproteins and the levels of high-density lipoproteins (LDL-C/HDL-C ratio). Correlations between the prognosis of ISSNHL and TC, TG, LDL-C, and LDL-C/HDL-C ratio were analyzed by univariable and multivariable logistic regression analyses.

RESULTS

The clinical effectiveness rate of patients with TC ranging from 5.2 to 6.2 mmol/L was significantly higher than that of patients with TC <5.2 mmol/L (P<0.001). No notable difference was found between patients with TC <5.2 mmol/L and patients with TC ≥6.2 mmol/L. The clinical effectiveness rate of patients in TG ranging from 1.7 mmol/L to 2.3 mmol/L was markedly higher than those in TG <1.7 mmol/L (P<0.001). No significant difference was found between patients with TG ranging from 2.3 to 5.6 mmol/L, TG ≥5.6 mmol/L, and TG <1.7 mmol/L. The clinical effectiveness rate of patients in LDL-C/HDL-C <1.5 was considerably higher than those in LDL-C/HDL-C ranging from 1.5 to 2.5, 2.5 to 3.5, and ≥3.5 (P<0.001).

CONCLUSIONS

Our findings indicated that TC, TG, and the LDL-C/HDL-C ratio are strongly associated with the prognosis of ISSNHL. These three indices could be recommended as independent markers to predict outcomes.

What dominates the changeable pharmacokinetics of natural sesquiterpene lactones and diterpene lactones: a review focusing on absorption and metabolism

Sesquiterpene lactones (STLs) and diterpene lactones (DTLs) are two groups of common phytochemicals with similar structures. It's frequently reported that both exhibit changeable pharmacokinetics (PK) in vivo, especially the unstable absorption and extensive metabolism. However, the recognition of their PK characteristics is still scattered. In this review, representative STLs (atractylenolides, alantolactone, costunolide, artemisinin, etc.) and DTLs (ginkgolides, andrographolide, diosbulbins, triptolide, etc.) as typical cases are discussed in detail. We show how the differences of treatment regimens and subjects alter the PK of STLs and DTLs, with emphasis on the effects from absorption and metabolism. These compounds tend to be quite permeable in intestinal epithelium, but gastrointestinal pH and efflux transporters (represented by P-glycoprotein) have great impact and result in the unstable absorption. As the only characteristic functional moiety, the metabolic behavior of lactone ring is not dominant. The α, β-unsaturated lactone moiety has the strongest metabolic activity. While with the increase of low-activity saturated lactone moieties, the metabolism is led by other groups more easily. The phase I (oxidation, reduction and hydrolysis reaction) and II metabolism (conjugation reaction) are both extensive. CYP450s, mainly CYP3A4, are largely involved in biotransformation. However, only UGTs (UGT1A3, UGT1A4, UGT2B4 and UGT2B7) has been mentioned in studies about phase II metabolic enzymes. Our work offers a beneficial reference for promoting the safety evaluation and maximizing the utilization of STLs and DTLs.

Differential Levels of Endoplasmic Reticulum Stress in Peripheral Blood Mononuclear Cells from Patients with Sudden Sensorineural Hearing Loss

Background

Sudden sensorineural hearing loss (SSNHL) is currently treated with a combination of drugs, predominantly with glucocorticoids (GCs). However, the mechanisms of action of GCs in SSNHL are unknown. This study aimed to analyze the role of endoplasmic reticulum stress (ERS) in SSNHL pathogenesis and prognosis.

Material/Methods

In this study, we evaluated the expression and activation status of the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-C/EBP homologous protein (CHOP) pathway in peripheral blood mononuclear cells (PBMCs) from patients with SSNHL and compared them with those in healthy controls. We also compared differences in expression of activating transcription factor 4 (ATF4) and CHOP before and after glucocorticoid treatment in patients with improved and unimproved SSNHL.

Results

Treatment with GCs significantly improved hearing in 55% of patients with SSNHL. Levels of phosphorylated PERK (p-PERK) and phosphorylated eukaryotic initiation factor 2α were increased in PBMCs from patients with SSNHL compared with healthy controls. ATF4 and CHOP expression were also significantly elevated. After treatment, the amount of ATF4 and CHOP proteins in PBMCs in the patients whose SSNHL improved was significantly reduced compared with the levels measured before treatment in all patients with SSNHL. The expression of the ATF4 and CHOP proteins in PBMCs in the unimproved group, however, was not significantly changed relative to pretreatment levels.

Conclusions

ERS may play a significant role in the pathogenesis of SSNHL, and the responsiveness of the condition to GC-mediated mitigation of ERS may be one of the key factors that affect patient prognosis.

Nimodipine and Steroid Combination Therapy for Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVE

To evaluate the treatment outcomes of nimodipine and steroid combination therapy for idiopathic sudden sensorineural hearing loss (ISSNHL).

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Seventy-eight patients who were diagnosed with ISSNHL were divided into two group based on the treatment strategies used: steroid+nimodipine (SN, n = 36) and steroid only (SO, n = 42) groups. Based on the level of hearing loss before treatment, subgroup analysis (<90 dB HL, SN-S versus SO-S groups; ≥90 dB HL, SN-P versus SO-P groups) was performed.

INTERVENTIONS

Nimodipine+dexamethasone versus dexamethasone alone.

MAIN OUTCOME MEASURES

Hearing thresholds and complete/partial recovery rate after treatment.

RESULTS

Hearing thresholds after treatment were not significantly different between the SN and SO groups (46.8 ± 29.4 versus 54.8 ± 27.6 dB HL, p = 0.218). However, the complete recovery rate was significantly higher in the SN group than in the SO group (41.7% versus 16.8%, p = 0.014). In subgroup analysis, the complete recovery rate was significantly higher in the SN-S group than in the SO-S group (60.9% versus 19.2%, p = 0.003), whereas the difference between the SN-P and SO-P groups was not significant (7.7% versus 12.5%, p = 0.672). The cumulative incidence of complete recovery was significantly higher in SN-S group than in the SO-S group (p = 0.005); the mean recovery time was 4.4 weeks (95% confidence interval [CI], 2.8-6.1) in the SN-S group and 8.8 weeks (95% CI, 7.0-10.5) in the SO-S group.

CONCLUSIONS

The results of this study suggest that nimodipine and steroid combination therapy for ISSNHL results in a higher complete recovery rate than steroid alone in patients with moderate to severe hearing loss.

Clinical Practice Guideline: Sudden Hearing Loss (Update)

OBJECTIVE

Sudden hearing loss is a frightening symptom that often prompts an urgent or emergent visit to a health care provider. It is frequently but not universally accompanied by tinnitus and/or vertigo. Sudden sensorineural hearing loss affects 5 to 27 per 100,000 people annually, with about 66,000 new cases per year in the United States. This guideline update provides evidence-based recommendations for the diagnosis, management, and follow-up of patients who present with sudden hearing loss. It focuses on sudden sensorineural hearing loss in adult patients aged ≥18 years and primarily on those with idiopathic sudden sensorineural hearing loss. Prompt recognition and management of sudden sensorineural hearing loss may improve hearing recovery and patient quality of life. The guideline update is intended for all clinicians who diagnose or manage adult patients who present with sudden hearing loss.

PURPOSE

The purpose of this guideline update is to provide clinicians with evidence-based recommendations in evaluating patients with sudden hearing loss and sudden sensorineural hearing loss, with particular emphasis on managing idiopathic sudden sensorineural hearing loss. The guideline update group recognized that patients enter the health care system with sudden hearing loss as a nonspecific primary complaint. Therefore, the initial recommendations of this guideline update address distinguishing sensorineural hearing loss from conductive hearing loss at the time of presentation with hearing loss. They also clarify the need to identify rare, nonidiopathic sudden sensorineural hearing loss to help separate those patients from those with idiopathic sudden sensorineural hearing loss, who are the target population for the therapeutic interventions that make up the bulk of the guideline update. By focusing on opportunities for quality improvement, this guideline should improve diagnostic accuracy, facilitate prompt intervention, decrease variations in management, reduce unnecessary tests and imaging procedures, and improve hearing and rehabilitative outcomes for affected patients.

METHODS

Consistent with the American Academy of Otolaryngology-Head and Neck Surgery Foundation's "Clinical Practice Guideline Development Manual, Third Edition" (Rosenfeld et al. Otolaryngol Head Neck Surg. 2013;148[1]:S1-S55), the guideline update group was convened with representation from the disciplines of otolaryngology-head and neck surgery, otology, neurotology, family medicine, audiology, emergency medicine, neurology, radiology, advanced practice nursing, and consumer advocacy. A systematic review of the literature was performed, and the prior clinical practice guideline on sudden hearing loss was reviewed in detail. Key Action Statements (KASs) were updated with new literature, and evidence profiles were brought up to the current standard. Research needs identified in the original clinical practice guideline and data addressing them were reviewed. Current research needs were identified and delineated.

RESULTS

The guideline update group made strong recommendations for the following: (KAS 1) Clinicians should distinguish sensorineural hearing loss from conductive hearing loss when a patient first presents with sudden hearing loss. (KAS 7) Clinicians should educate patients with sudden sensorineural hearing loss about the natural history of the condition, the benefits and risks of medical interventions, and the limitations of existing evidence regarding efficacy. (KAS 13) Clinicians should counsel patients with sudden sensorineural hearing loss who have residual hearing loss and/or tinnitus about the possible benefits of audiologic rehabilitation and other supportive measures. These strong recommendations were modified from the initial clinical practice guideline for clarity and timing of intervention. The guideline update group made strong recommendations against the following: (KAS 3) Clinicians should not order routine computed tomography of the head in the initial evaluation of a patient with presumptive sudden sensorineural hearing loss. (KAS 5) Clinicians should not obtain routine laboratory tests in patients with sudden sensorineural hearing loss. (KAS 11) Clinicians should not routinely prescribe antivirals, thrombolytics, vasodilators, or vasoactive substances to patients with sudden sensorineural hearing loss. The guideline update group made recommendations for the following: (KAS 2) Clinicians should assess patients with presumptive sudden sensorineural hearing loss through history and physical examination for bilateral sudden hearing loss, recurrent episodes of sudden hearing loss, and/or focal neurologic findings. (KAS 4) In patients with sudden hearing loss, clinicians should obtain, or refer to a clinician who can obtain, audiometry as soon as possible (within 14 days of symptom onset) to confirm the diagnosis of sudden sensorineural hearing loss. (KAS 6) Clinicians should evaluate patients with sudden sensorineural hearing loss for retrocochlear pathology by obtaining magnetic resonance imaging or auditory brainstem response. (KAS 10) Clinicians should offer, or refer to a clinician who can offer, intratympanic steroid therapy when patients have incomplete recovery from sudden sensorineural hearing loss 2 to 6 weeks after onset of symptoms. (KAS 12) Clinicians should obtain follow-up audiometric evaluation for patients with sudden sensorineural hearing loss at the conclusion of treatment and within 6 months of completion of treatment. These recommendations were clarified in terms of timing of intervention and audiometry and method of retrocochlear workup. The guideline update group offered the following KASs as options: (KAS 8) Clinicians may offer corticosteroids as initial therapy to patients with sudden sensorineural hearing loss within 2 weeks of symptom onset. (KAS 9a) Clinicians may offer, or refer to a clinician who can offer, hyperbaric oxygen therapy combined with steroid therapy within 2 weeks of onset of sudden sensorineural hearing loss. (KAS 9b) Clinicians may offer, or refer to a clinician who can offer, hyperbaric oxygen therapy combined with steroid therapy as salvage therapy within 1 month of onset of sudden sensorineural hearing loss.

DIFFERENCES FROM PRIOR GUIDELINE

Incorporation of new evidence profiles to include quality improvement opportunities, confidence in the evidence, and differences of opinion Included 10 clinical practice guidelines, 29 new systematic reviews, and 36 new randomized controlled trials Highlights the urgency of evaluation and initiation of treatment, if treatment is offered, by emphasizing the time from symptom occurrence Clarification of terminology by changing potentially unclear statements; use of the term sudden sensorineural hearing loss to mean idiopathic sudden sensorineural hearing loss to emphasize that >90% of sudden sensorineural hearing loss is idiopathic sudden sensorineural hearing loss and to avoid confusion in nomenclature for the reader Changes to the KASs from the original guideline: KAS 1-When a patient first presents with sudden hearing loss, conductive hearing loss should be distinguished from sensorineural. KAS 2-The utility of history and physical examination when assessing for modifying factors is emphasized. KAS 3-The word "routine" is added to clarify that this statement addresses nontargeted head computerized tomography scan that is often ordered in the emergency room setting for patients presenting with sudden hearing loss. It does not refer to targeted scans, such as temporal bone computerized tomography scan, to assess for temporal bone pathology. KAS 4-The importance of audiometric confirmation of hearing status as soon as possible and within 14 days of symptom onset is emphasized. KAS 5-New studies were added to confirm the lack of benefit of nontargeted laboratory testing in sudden sensorineural hearing loss. KAS 6-Audiometric follow-up is excluded as a reasonable workup for retrocochlear pathology. Magnetic resonance imaging, computerized tomography scan if magnetic resonance imaging cannot be done, and, secondarily, auditory brainstem response evaluation are the modalities recommended. A time frame for such testing is not specified, nor is it specified which clinician should be ordering this workup; however, it is implied that it would be the general or subspecialty otolaryngologist. KAS 7-The importance of shared decision making is highlighted, and salient points are emphasized. KAS 8-The option for corticosteroid intervention within 2 weeks of symptom onset is emphasized. KAS 9-Changed to KAS 9A and 9B. Hyperbaric oxygen therapy remains an option but only when combined with steroid therapy for either initial treatment (9A) or salvage therapy (9B). The timing of initial therapy is within 2 weeks of onset, and that of salvage therapy is within 1 month of onset of sudden sensorineural hearing loss. KAS 10-Intratympanic steroid therapy for salvage is recommended within 2 to 6 weeks following onset of sudden sensorineural hearing loss. The time to treatment is defined and emphasized. KAS 11-Antioxidants were removed from the list of interventions that the clinical practice guideline recommends against using. KAS 12-Follow-up audiometry at conclusion of treatment and also within 6 months posttreatment is added. KAS 13-This statement on audiologic rehabilitation includes patients who have residual hearing loss and/or tinnitus who may benefit from treatment. Addition of an algorithm outlining KASs Enhanced emphasis on patient education and shared decision making with tools provided to assist in same.

A systematic review and network meta-analysis of existing pharmacologic therapies in patients with idiopathic sudden sensorineural hearing loss

BACKGROUND

Hearing loss is one of the leading causes of disability worldwide. Patients with hearing loss experience impaired quality of life, as well as emotional and financial consequences that affect both themselves and their families. Idiopathic sudden sensorineural hearing loss (ISSNHL) is a common but difficult to treat condition that has a sudden onset of ≤ 72 hour associated with various etiologies, with the majority of cases being idiopathic. There exists a wide range of therapeutic options, however, the uncertainty surrounding their comparative efficacy and safety makes selection of treatment difficult. This systematic review and network meta-analysis (NMA) assessed the relative effects of competing treatments for management of ISSNHL.

METHODS

A protocol for this review was registered with PROSPERO (CRD42017073756). A detailed search of MEDLINE, Embase and the Cochrane Library from inception to February 8th, 2018 was carried out by an experienced information specialist. Grey literature was also searched. Screening full-text records, and risk of bias assessment were carried out independently by two reviewers, and disagreements were resolved through consensus or third party adjudication, while data was collected by one reviewer and verified by a second reviewer. Bayesian network meta-analyses (NMA) were performed to inform comparisons between interventions for a priori specified outcomes that included pure tone average (PTA) improvement and hearing recovery.

RESULTS

The search identified a total of 1,138 citations, of which 613 remained for review after removal of duplicates. Of these, 23 publications describing 19 unique studies (total sample size of 1,527) met our a priori eligibility criteria, that were assessed to be at unclear or high risk of bias on several domains. We identified data on several interventions for ISSNHL therapy and were able to construct treatment networks consisting of six intervention groups that included placebo; intratympanic (IT) steroid; IT plus systemic steroid; per oral (PO) steroid; intravenous (IV) steroid; and IV plus PO steroid for our NMAs. IT plus systemic steroids demonstrated the largest difference in PTA improvement compared to placebo (25.85 dB, 95% CrI 7.18-40.58), followed by IV plus PO steroids (22.06 dB, 95% CrI 1.24-39.17), IT steroids (18.24 dB, 95% CrI 3.00-29.81). We observed that the difference of PTA improvement between each intervention and placebo diminished over time, attributed to spontaneous recovery. The binary outcomes of hearing recovery demonstrated similar relative ordering of interventions but were less sensitive than PTA improvement to capture the significant differences between interventions and placebo.

CONCLUSION

Unclear to high risk of bias trials rated IT plus systemic steroid treatment as the best among the six interventions compared, and all active treatments were better than placebo in improving PTA. However, it should be noted that certain comparisons were based on indirect evidence only or few studies of small sample size, and analyses were unable to control for steroid type and dosage. Given these limitations, further data originating from methodologically sound and rigorous trials with adequate reporting are needed to confirm our findings.

Traditional oriental medicine for sensorineural hearing loss: Can ethnopharmacology contribute to potential drug discovery?

ETHNOPHARMACOLOGICAL RELEVANCE

In Traditional Oriental Medicine (TOM), the development of hearing pathologies is related to an inadequate nourishment of the ears by the kidney and other organs involved in regulation of bodily fluids and nutrients. Several herbal species have historically been prescribed for promoting the production of bodily fluids or as antiaging agents to treat deficiencies in hearing.

AIM OF REVIEW

The prevalence of hearing loss has been increasing in the last decade and is projected to grow considerably in the coming years. Recently, several herbal-derived products prescribed in TOM have demonstrated a therapeutic potential for acquired sensorineural hearing loss and tinnitus. Therefore, the aims of this review are to provide a comprehensive overview of the current known efficacy of the herbs used in TOM for preventing different forms of acquired sensorineural hearing loss and tinnitus, and associate the traditional principle with the demonstrated pharmacological mechanisms to establish a solid foundation for directing future research.

METHODS

The present review collected the literature related to herbs used in TOM or related compounds on hearing from Chinese, Korean, and Japanese herbal classics; library catalogs; and scientific databases (PubMed, Scopus, Google Scholar; and Science Direct).

RESULTS

This review shows that approximately 25 herbal species and 40 active compounds prescribed in TOM for hearing loss and tinnitus have shown in vitro or in vivo beneficial effects for acquired sensorineural hearing loss produced by noise, aging, ototoxic drugs or diabetes. The inner ear is highly vulnerable to ischemia and oxidative damage, where several TOM agents have revealed a direct effect on the auditory system by normalizing the blood supply to the cochlea and increasing the antioxidant defense in sensory hair cells. These strategies have shown a positive impact on maintaining the inner ear potential, sustaining the production of endolymph, reducing the accumulation of toxic and inflammatory substances, preventing sensory cell death and preserving sensory transmission. There are still several herbal species with demonstrated therapeutic efficacy whose mechanisms have not been deeply studied and others that have been traditionally used in hearing loss but have not been tested experimentally. In clinical studies, Ginkgo biloba, Panax ginseng, and Astragalus propinquus have demonstrated to improve hearing thresholds in patients with sensorineural hearing loss and alleviated the symptoms of tinnitus. However, some of these clinical studies have been limited by small sample sizes, lack of an adequate control group or contradictory results.

CONCLUSIONS

Current therapeutic strategies have proven that the goal of the traditional oriental medicine principle of increasing bodily fluids is a relevant approach for reducing the development of hearing loss by improving microcirculation in the blood-labyrinth barrier and increasing cochlear blood flow. The potential benefits of TOM agents expand to a multi-target approach on different auditory structures of the inner ear related to increased cochlear blood flow, antioxidant, anti-inflammatory, anti-apoptotic and neuroprotective activities. However, more research is required, given the evidence is very limited in terms of the mechanism of action at the preclinical in vivo level and the scarce number of clinical studies published.

Efficacy and safety of Ginkgo biloba extract as an "add-on" treatment to metformin for patients with metabolic syndrome: a pilot clinical study

Background and aim

Ginkgo biloba (GKB) extract has shown to be beneficial in experimental models of metabolic and inflammatory disorders such as diabetes and metabolic syndrome (MTS). The objective of this pilot clinical study was to evaluate the effects of GKB extract as an “add-on” treatment with metformin (Met) in MTS patients.

Patients and methods

We performed a randomized, placebo-controlled, double-blinded clinical study in subjects with MTS. Forty patients completed the 90-day clinical trial and were randomly allocated to administer either GKB extract (120 mg capsule/day) or placebo (120 mg starch/day) as an add-on treatment with their currently used doses of Met for 90 days. During the study, body mass index (BMI), waist circumference (WC), serum leptin, glycated hemoglobin (HbA1c), fasting serum glucose (FSG), insulin, insulin resistance (IR), visceral adiposity index (VAI), lipid profile, and the inflammatory markers high sensitive C-reactive protein (hsCRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were evaluated.

Results

GKB extract significantly decreases HbA1c, FSG and insulin levels, IR, BMI, WC, VAI, serum leptin, and the inflammatory markers compared to baseline values. Simultaneously, GKB did not negatively affect the functions of the liver, kidney, and hematopoietic system.

Conclusion

The use of GKB extract as an adjuvant with Met was effective in improving the outcome of patients with MTS.

[The diagnostics and treatment of tympanophonia]

Tympanophonia can be a consequence of a variety of diseases and pathological conditions diagnostics of which encounters difficulties. The comprehensive clinical examination of the patient is necessary to determine the cause of tympanophonia including elucidation of the following characteristics: initial (acute or gradual) sensation of sound in the ear(s), duration of persisting clinical manifestations, the presence of an acoustic or craniocerebral injury, characteristics of the noise, viz. continuous or intermittent, clicking sounds, paroxysmal or pulsed noise (synchronous with the heart beating), fluctuating, audible to the patient alone or to the surrounding people as well, unilateral and bilateral noises (either symmetric or asymmetric), perception of noise in the head rather than ears., high- and low-pitched noise together with the accompanying neurological symptoms. The analysis of these characteristics makes it possible to differentiate between objective and subjective sensation of noise in the ear(s), determine the amount of additional studies needed for the evaluatio of the conditions of a given patient, identify the possible cause of tympanophonia, establish the nosological diagnosis, and distinguish a group of the patients in need of emergency otological management.

Analysis of cases managed by the otolaryngology service in the Chinese military peacekeeping level 2 medical treatment facility in Mali

OBJECTIVES

As part of the UN peacekeeping mission in Mali, the People's Republic of China have deployed a level 2 medical treatment facility (CHN L2). The aim of this study was to review the cases managed by the otolaryngology service within this facility.

METHODS

The medical records of all patients treated by the otolaryngology service at the CHN L2 from 1 March 2015 to 1 March 2018 were retrospectively assessed.

RESULTS

614/10189 (6%) of all cases seen in the hospital during this period were referred to the otolaryngology service. 7/614 cases required admission to hospital (1.14%) and 40/614 cases required surgery (6.51%). 3/40 cases requiring surgery (7.5%) were performed under general anaesthesia and 37 cases (92.5%) were under local anaesthesia. The most common surgical treatment was facial soft-tissue injury debridement and closure. Acute rhinosinusitis was the most common diagnosis, followed by acute pharyngitis and allergic rhinitis. Four patients required medical evacuation to a level 3 medical treatment facility.

CONCLUSIONS

Disease non-battle injury in the form of ear disease was the most common presentation. Maxillofacial soft-tissue injury was the most common cause of traumatic injury. There were limits that the service could provide in terms of medical equipment and consumables, necessitating increased training of otolaryngologists prior to deployment.

Clinical and genomic safety of treatment with Ginkgo biloba L. leaf extract (IDN 5933/Ginkgoselect®Plus) in elderly: a randomised placebo-controlled clinical trial [GiBiEx]

BACKGROUND

Numerous health benefits have been attributed to the Ginkgo biloba leaf extract (GBLE), one of the most extensively used phytopharmaceutical drugs worldwide. Recently, concerns of the safety of the extract have been raised after a report from US National Toxicology Program (NTP) claimed high doses of GBLE increased liver and thyroid cancer incidence in mice and rats. A safety study has been designed to assess, in a population of elderly residents in nursing homes, clinical and genomic risks associated to GBLE treatment.

METHODS

GiBiEx is a multicentre randomized clinical trial, placebo controlled, double blinded, which compared subjects randomized to twice-daily doses of either 120-mg of IDN 5933 (also known as Ginkgoselect®Plus) or to placebo for a 6-months period. IDN 5933 is extracted from dried leaves and contains 24.3% flavone glycosides and 6.1% of terpene lactones (2.9% bilobalide, 1.38% ginkgolide A, 0.66% ginkgolide B, 1.12% ginkgolide C) as determined by HPLC. The study was completed by 47 subjects, 20 in the placebo group and 27 in the treatment group. Clinical (adverse clinical effect and liver injury) and genomic (micronucleus frequency, comet assay, c-myc, p53, and ctnnb1 expression profile in lymphocytes) endpoints were assessed at the start and at the end of the study.

RESULTS

No adverse clinical effects or increase of liver injury markers were reported in the treatment group. The frequency of micronuclei [Mean Ratio (MR) = 1.01, 95% Confidence Intervals (95% CI) 0.86-1.18), and DNA breaks (comet assay) (MR = 0.91; 95% CI 0.58-1.43), did not differ in the two study groups. No significant difference was found in the expression profile of the three genes investigated.

CONCLUSIONS

None of the markers investigated revealed a higher risk in the treatment group, supporting the safety of IDN 5933 at doses prescribed and for duration of six months.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03004508 , December 20, 2016. Trial retrospectively registered.

The Protective Effect of Egb 761 Against 3-Nitropropionic Acid-Induced Hearing Loss: The Role of Sirtuin 1

OBJECTIVES

Local administration of 3-nitropropionic acid (3-NP) to the inner ear induces sensorineural hearing loss. Several studies have shown the otoprotective effects of ginkgo biloba extract EGb 761. Moreover, EGb 761 has been reported to activate Sirtuin 1 (SIRT1). The present study was designed to investigate whether EGb 761 prevents 3-NP-induced sensorineural hearing loss and determine its effects on the expression of SIRT1.

METHODS

Sprague Dawley rats were divided into four experimental groups: control group receiving vehicle of 3-NP, EGb group receiving EGb 761, 3-NP group receiving 3-NP, and EGb+3-NP group receiving EGb 761 and 3-NP. EGb 761 was given orally for 5 days. The 3-NP solution was injected into the tympanum 3 days after the start of EGb 761 administration. The auditory brainstem response was recorded before and after the injection. At 4 weeks after the administration of 3-NP or vehicle of 3-NP, cochleae were harvested, and hematoxylin and eosin staining and immunohistochemistry for SIRT1 antibody were performed.

RESULTS

EGb+3-NP group showed significantly lower threshold shifts than 3-NP group. There was a significant preservation of type II fibrocytes and spiral ganglion cells in EGb+3-NP group than in 3-NP group. In EGb+3-NP group, there was a significantly greater number of SIRT1 immunopositive type II fibrocytes and spiral ganglion cells than in 3-NP group. Calculating the percentage of SIRT1 immunoreactive type II fibrocytes and spiral ganglion cells in viable type II fibrocytes and spiral ganglion cells, respectively, EGb+3-NP group showed significantly higher SIRT1 immunoreactive cells than 3-NP group.

CONCLUSION

These results suggest that EGb 761 may prevent hearing loss induced by 3-NP in an acute ototoxic animal model, which appears to be related with SIRT1 expression.