Upper Respiratory Symptoms as Long COVID: Insight from a Multicenter Cohort Study

Objective

This study aimed to investigate the clinical features of long COVID cases presenting with upper respiratory symptoms, a topic not yet fully elucidated.

Study Design

Prospective cohort study.

Setting

A multicenter study involving 26 medical facilities in Japan.

Methods

Inclusion criteria were patients aged ≥18 years old with a confirmed COVID-19 diagnosis via severe acute respiratory syndrome coronavirus 2 polymerase chain reaction or antigen testing, who were hospitalized at the participating medical facilities. Analyzing clinical information and patient-reported outcomes from 1009 patients were analyzed. The outcome measured the degree of initial symptoms for taste or olfactory disorders and assessed the likelihood of these symptoms persisting as long COVID, as well as the impact on quality of life if the upper respiratory symptoms persisted as long COVID.

Results

Patients with high albumin, low C-reactive protein, and low lactate dehydrogenase in laboratory tests tended to experience taste or olfactory disorders as part of long COVID. Those with severe initial symptoms had a higher risk of experiencing residual symptoms at 3 months, with an odds ratio of 2.933 (95% confidence interval [CI], 1.282-6.526) for taste disorders and 3.534 (95% CI, 1.382-9.009) for olfactory disorders. Presence of upper respiratory symptoms consistently resulted in lower quality of life scores.

Conclusion

The findings from this cohort study suggest that severe taste or olfactory disorders as early COVID-19 symptoms correlate with an increased likelihood of persistent symptoms in those disorders as long COVID.

Comprehensive analysis of long COVID in a Japanese nationwide prospective cohort study

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly since 2019, and the number of reports regarding long COVID has increased. Although the distribution of long COVID depends on patient characteristics, epidemiological data on Japanese patients are limited. Hence, this study aimed to investigate the distribution of long COVID in Japanese patients. This study is the first nationwide Japanese prospective cohort study on long COVID.

METHODS

This multicenter, prospective cohort study enrolled hospitalized COVID-19 patients aged ≥18 years at 26 Japanese medical institutions. In total, 1200 patients were enrolled. Clinical information and patient-reported outcomes were collected from medical records, paper questionnaires, and smartphone applications.

RESULTS

We collected data from 1066 cases with both medical records and patient-reported outcomes. The proportion of patients with at least one symptom decreased chronologically from 93.9% (947/1009) during hospitalization to 46.3% (433/935), 40.5% (350/865), and 33.0% (239/724) at 3, 6, and 12 months, respectively. Patients with at least one long COVID symptom showed lower quality of life and scored higher on assessments for depression, anxiety, and fear of COVID-19. Female sex, middle age (41-64 years), oxygen requirement, and critical condition during hospitalization were risk factors for long COVID.

CONCLUSIONS

This study elucidated the symptom distribution and risks of long COVID in the Japanese population. This study provides reference data for future studies of long COVID in Japan.

Tests of human auditory temporal resolution: preliminary investigation of ZEST parameters for amplitude modulation detection

Auditory temporal resolution plays a critical role in the everyday experience of listening to complex acoustic patterns. Amplitude modulation detection thresholds are widely used to measure auditory temporal resolution. In an attempt to develop a standardized clinical test of auditory temporal resolution, we used ZEST (Zippy Estimation by Sequential Testing, a Bayesian threshold estimation procedure, to measure amplitude modulation detection thresholds. ZEST utilizes prior knowledge about a listener's thresholds, as represented by a probability density function of the thresholds, and psychometric functions of the listener's responses. This paper reports a preliminary study in which ZEST parameters that could be used for measurements of amplitude modulation detection thresholds were sought. For this purpose, we created histograms of the detection thresholds for a wide range of modulation frequencies, measured the psychometric functions of amplitude modulation detection, and performed computer simulations of ZEST threshold estimation. The results suggested that, with appropriately-set parameters, ZEST allows for the accurate estimation of amplitude modulation detection thresholds within 20 trials.

Association Between Multiple Sclerosis and the Symptoms of Vertigo and Facial Nerve Palsy

Patients with vertigo and facial nerve palsy as initial symptoms are rarely diagnosed with multiple sclerosis. A 43-year-old woman presented to our department with symptoms of vertigo and right facial nerve palsy (Yanagihara 16-point system [total score, 40] or House- Brackmann grade IV [obvious facial weakness]). On the day of the visit, she presented with right eye abduction, left eye adduction, and complaints of diplopia. Based on magnetic resonance imaging findings, she was diagnosed with clinically isolated syndrome, which is an early manifestation of multiple sclerosis. She was treated with intravenous methylprednisolone. Otolaryngologists often suspect Hunt's syndrome in patients who present with facial nerve palsy combined with vertigo. However, herein, we report our experience with an extremely rare case of a patient with atypical nystagmus symptoms, eye movement disorder, and diplopia secondary to facial palsy and vertigo, who presented with a clinical course different from that of Hunt's syndrome.

Barrier Factors of Adherence to Dupilumab Self-Injection for Severe Allergic Disease: A Non-Interventional Open-Label Study

PURPOSE

The status of dupilumab self-injection at home is not well understood. We therefore aimed to identify the barriers to adherence to dupilumab self-injection.

PATIENTS AND METHODS

This non-interventional open-label study was conducted between March 2021 and July 2021. Patients with atopic dermatitis, bronchial asthma, and chronic rhinosinusitis with nasal polyps receiving dupilumab, from 15 sites, were requested to complete a self-administered questionnaire regarding the frequency and effectiveness of dosing as well as their use and satisfaction with dupilumab. Barriers to adherence were assessed using the Adherence Starts with Knowledge-12.

RESULTS

We included 331 patients who used dupilumab for atopic dermatitis (n = 164), chronic rhinosinusitis with nasal polyps (n = 102), and bronchial asthma (n = 65). The median efficacy of dupilumab scored 9.3 on the visual analog scale. Overall, 85.5% of the patients self-injected dupilumab, and 70.7% perfectly complied with the established injection dates. The pre-filled pen was significantly superior to the conventional syringe in terms of usability, operability, ease of pushing the plunger, and patient satisfaction. However, the pre-filled pen caused more pain during self-injection than did the syringe. Multivariate logistic regression analysis showed that adherence decreased with longer dupilumab treatment duration (p = 0.017) and was not associated with age, sex, underlying disease, or device type. There was a difference in responses related to "inconvenience/forgetfulness" between the good and poor adherence groups.

CONCLUSION

The pre-filled dupilumab pen was superior to the syringe in terms of usability, operability, ease of pushing the plunger, and satisfaction. Repetitive instructions are recommended for preventing poor adherence to dupilumab self-injection.

Efficacy of transtympanic infusion of dexamethasone into the tympanic cavity in mice with acute sensorineural hearing loss associated with cytomegalovirus infection

BACKGROUND

There is no report on acute sensorineural hearing loss with congenital cytomegalovirus (cCMV) infection in basic experiments.

AIMS/OBJECTIVES

The aim of this study was to evaluate the effect of dexamethasone, an anti-inflammatory steroid, on acute sensorineural hearing loss in the mouse cytomegalovirus (MCMV) infection model mice.

MATERIAL AND METHODS

Sensorineural hearing loss model mice were divided into two groups, one with and one without intratympanic dexamethasone. Dexamethasone was injected into the tympanic cavity of only the right ear, and hearing ability was assessed at the ages of three, six, and eight weeks by auditory brainstem response measurement.

RESULTS

Among the 23 mice intratympanically injected with dexamethasone (15 μg/mouse) at the age of three weeks, five (21.7%) had a hearing improvement of at least 10 dB and 18 (78.3%) had no improvement at the age of six weeks. Among the 19 mice that did not receive a dexamethasone injection, one (5.3%) showed improvement and 18 (94.7%) showed no improvement (p = 0.129).

CONCLUSIONS AND SIGNIFICANCE

In this study, transtympanic infusion of dexamethasone into the tympanic cavity was effective in some mice with sensorineural hearing loss, suggesting that, in addition to angiogenesis, anti-inflammatory activity might be a mechanism of treatment for hearing loss.

Transcanal endoscopic ear surgery for management of ossicular malformation: clinical outcomes of 17 cases

BACKGROUND

In recent years, transcanal endoscopic ear surgery (TEES) is known as an innovative and minimally invasive surgery.

AIMS

To clarify the usefulness of TEES for the ossicular malformation, we performed a retrospective study.

MATERIAL AND METHODS

We examined cases of ossicular malformation performed using TEES at our hospital between April 2015 and April 2020.

RESULTS

The hearing level results were countable for 16 cases. Post-operative hearing levels were significantly improved. Transient nausea, tongue paralysis, and taste disorders were observed; however, no other complications were observed. In 2015-2018, some of the cases required the assistance of a surgical microscope. In contrast, all the cases were performed by TEES after 2019 using a powered device to curve the canal.

CONCLUSIONS AND SIGNIFICANCE

TEES requires considerable training, and the sensation of depth is difficult to acquire. However, this less invasive method is also helpful for ossicular malformation cases.

In Vivo Imaging Analysis of an Inner Ear Drug Delivery in Mice: Comparison of Inner Ear Drug Concentrations Over Time

Treatment for inner ear regeneration and protection needs local injection of steroid or new drug for inner ear regeneration into the round window membrane (RWM) in cochlea, but a systemic injection is not available due to its systemic side effects. However, pharmacokinetics of therapeutic agents or steroid locally injected into the inner ear is not well known. Hence, we introduce a new method for the real-time observation of drug delivery in transgenic animals in vivo. We exemplify mice which contain a firefly luciferase (FLuc) gene expression cassette regulated by the murine glial fibrillary acidic protein (GFAP) promoter. Luciferin delivered into the inner ear of those mice reacts with FLuc that is expressed in the GFAP-expressing cells in the cochlear nerve and spiral ganglion, and the resulting bioluminescence is detected by a camera. Using this system, we show the imaging of pharmacokinetic differences between local and systemic (intravenous and subcutaneous) injections of the inner ear.

Comprehensive and long-term surveys of COVID-19 sequelae in Japan, an ambidirectional multicentre cohort study: study protocol

INTRODUCTION

The rapid spread of COVID-19 posed a global burden. Substantial number of people died of the disease in the acute phase of infection. In addition, a significant proportion of patients have been reported to suffer from post-acute phase symptoms, sequelae of COVID-19, which may negatively influence the quality of daily living and/or socioeconomic circumstances of the patients. However, no previous study has comprehensively and objectively assessed the quality of life of patients by using existing international scales. Further, evidence of socioeconomic consequences among patients with COVID-19 is scarce. To address the multidimensional issues from sequelae of COVID-19, evidence from comprehensive surveys beyond clinical perspectives is critical that investigates health, and social determinants of disease progression as well as socioeconomic consequences at a large scale.

METHODS AND ANALYSIS

In this study, we plan to conduct a nationwide and comprehensive survey for the sequelae of COVID-19 in a total of 1000 patients diagnosed at 27 hospitals throughout Japan. This study will evaluate not only the health-related status of patients from clinical perspectives but also the Health-related Quality of Life (HRQoL) scores, socioeconomic status and consequences to discuss the sequelae of the disease and the related risk factors. The primary endpoint is the frequency of long-term complications of COVID-19 infection. The secondary endpoints are risk factors for progression to sequelae of COVID-19 infection. The study will provide robust and important evidence as a resource to tackle the issues from the sequelae of COVID-19 from the multi-dimensional perspectives.

ETHICS AND DISSEMINATION

This trial was approved by the Keio University School of Medicine Ethics Committee (20200243, UMIN000042299). The results of this study will be reported at a society meeting or published in a peer-reviewed journal.

Comparison of Drug Availability in the Inner Ear After Oral, Transtympanic, and Combined Administration

Although combination of oral and transtympanic drug therapy (CT) has been proved more effective and safer for idiopathic sudden sensorineural hearing loss (ISSNHL) by some clinical trials, there are few laboratory researches on the pharmacokinetics in the inner ear following CT on account of structural limitations of the inner ear. The aim of the present study was to investigate the pharmacokinetic behaviors of CT in the inner ear of mice. Eighteen transgenic GFAP-Luc mice which express luciferase in cochlear spiral ganglion cells were divided into oral administration (OR) group, transtympanic injection route (TT) group and CT group, and luciferin was delivered into the inner ear of these mice through oral, transtympanic or combined routes, respectively. A new in vivo imaging system was used to observe luciferin/luciferase signals and the compare the pharmacokinetics of different administration routes in the inner ear of mice. Bioluminescence signals were observed in the inner ear 3.3 ± 2.6 min after CT, significantly earlier than that of OR group (15.8 ± 7.4 min). CT owned the longest reaching-peak time and largest area under the curve (AUC) among three groups. Compared to TT, CT had longer biological half-life and higher AUC value, but did not displayed stronger peak value. There were significant differences in the peak values between OR group and TT group and between OR group and CT group. This study suggests that the OR route is less effective than the TT or CT route, and combination of OR and TT can deliver more drugs into the inner ear and confer a longer therapeutic window, but cannot increase drug intensity.

Eosinophilic annular erythema showing eosinophil cytolytic ETosis successfully treated with benralizumab

A 56-year-old woman presented with repeated swelling of the lips and face. She had a history of childhood asthma; she had a recurrence of asthma when she was 54 years old and was taking inhaled corticosteroids, and other antiasthma drugs. The swelling of her lips and face improved temporarily with oral corticosteroids (OCS), but recurred soon after discontinuing OCS. Her peripheral blood eosinophil count was 632/μL (9.3%), and her serum was negative for myeloperoxidase-anti-neutrophil cytoplasmic antibody and serine proteinase3-anti-neutrophil cytoplasmic antibody. Hematoxylin and eosin staining of her back skin revealed abundant eosinophilic infiltrate around the vascular area of the shallow dermis layer, but no evidence of vasculitis and we diagnosed her as eosinophilic annular erythema (EAE). Punctate staining of galectin-10, chromatolytic eosinophils, and net-like DNA was also evident in close proximity to the free granules, indicating extracellular vesicles and eosinophil extracellular traps (ETosis). We started daily OCS to control her asthma and skin eruption/oedema. Three months after administering daily OCS, benralizumab was initiated for withdrawal from OCS dependence and treatment of severe asthma. After initiation of benralizumab, her skin and subcutaneous tissue symptoms promptly improved. OCS was discontinued, and no edematous erythema has been observed since then. Bronchial asthma has also been well-controlled. This is the first report on the evidence of eosinophil ETosis in the dermis of EAE patients and the efficacy of benralizumab in a patient with EAE. Benralizumab may be a useful drug for treating refractory EAE with severe eosinophilic asthma.

Analysis of Pharmacokinetics in the Cochlea of the Inner Ear

Hearing loss affects >5% of the global population and therefore, has a great social and clinical impact. Sensorineural hearing loss, which can be caused by different factors, such as acoustic trauma, aging, and administration of certain classes of drugs, stems primarily from a dysfunction of the cochlea in the inner ear. Few therapeutic strategies against sensorineural hearing loss are available. To develop effective treatments for this disease, it is crucial to precisely determine the behavior of ototoxic and therapeutic agents in the microenvironment of the cochlea in live animals. Since the 1980s, a number of studies have addressed this issue by different methodologies. However, there is much less information on pharmacokinetics in the cochlea than that in other organs; the delay in ontological pharmacology is likely due to technical difficulties with accessing the cochlea, a tiny organ that is encased with a bony wall and has a fine and complicated internal structure. In this review, we not only summarize the observations and insights obtained in classic and recent studies on pharmacokinetics in the cochlea but also describe relevant analytical techniques, with their strengths, limitations, and prospects.

Multicenter phase III trial of regenerative treatment for chronic tympanic membrane perforation

OBJECTIVE

To evaluate the efficacy and safety of regenerative treatment for tympanic membrane perforation (TMP) using gelatin sponge, basic fibroblast growth factor (bFGF), and fibrin glue.

METHODS

This was a multicenter, non-randomized, single-arm study conducted at tertiary referral centers. Twenty patients with chronic TMP (age 23-78 years, 6 males, 14 females) were registered from three institutions. All treated patients were included in the safety analysis population. The edges of the TMP were disrupted mechanically by myringotomy and several pieces of gelatin sponge immersed in bFGF were placed and fixed with fibrin glue to cover the perforation. The TMP was examined 4 ± 1 weeks later. The protocol was repeated up to four times until closure was complete. The main outcome measures were closure or a decrease in size of the TMP, hearing improvement, and air-bone gap evaluated 16 weeks after the final regenerative procedure (FRP). Adverse events (AEs) were monitored throughout the study.

RESULTS

Total closure of the TMP at 16 weeks was achieved in 15 out of 20 patients (75.0%, 95% confidence interval [CI]: 50.9%-91.3%) and the mean decrease in size was 92.2% (95%CI: 82.9%-100.0%). The ratio of hearing improvement and the air-bone gap at 16 weeks after FRP were 100% (20/20; 95%CI: 83.2%-100%) and 5.3 ± 4.2 dB (p <0.0001), respectively. Thirteen out of 20 patients (65.0%) experienced at least one AE, but no serious AEs occurred.

CONCLUSION

The results indicate that the current regenerative treatment for TMP using gelatin sponge, bFGF, and fibrin glue is safe and effective.

Delayed facial palsy after cochlear implantation caused by reactivation of Herpesvirus: A case report and review of the literature

Cochlear implantation has many complications; however, delayed facial palsy is relatively rare. In this report, we present the case of a 60-year-old woman with delayed facial palsy after cochlear implantation. Eleven days after the operation, the patient complained of right facial palsy (Yanagihara score 6, House-Brackmann [HB] grade VI). Herpes virus reactivation and local bacterial infection were considered as possible causes of the facial paralysis. A blood test revealed an increase in viral antibody titer, and the patient was diagnosed as having herpes virus reactivation. She was treated with antiviral therapy for the facial palsy until resolution. Slight mouth weakness continued even at 1.5 months (Yanagihara score 34, HB II) but eventually resolved at 3 months (Yanagihara score 40, HB I). Delayed facial palsy is a rare but serious complication that can occur with viral reactivation regardless of the competence of the surgical procedure. Therefore, it is important to inform patients preoperatively regarding the risk of not only immediate but also delayed postoperative facial paralysis.

Surgical treatment of otosclerosis using a unique stapes prosthesis without a hook

BACKGROUND

During stapes surgery, the Teflon wire piston prosthesis is prone to postoperative 'slips' and subsequent necrosis and fracture of the long process of the incus.

AIMS/OBJECTIVE

We invented and used a novel cup-shaped apatite prosthesis to reduce the incidence of necrosis of the long process of the incus and analysed the postoperative results.

MATERIAL AND METHODS

Thirty-one ears in 25 patients with otosclerosis who underwent stapes surgery with our apatite prosthesis were evaluated.

RESULTS

The air conduction improved by 24.0 dB (the average) from pre- to post-operation. Additionally, 84.8% of patients achieved an air-bone gap of ≤10 dB for the 4-frequency measurements (p < .01).

CONCLUSIONS

Our findings indicate that our new prosthesis was associated with a good postoperative prognosis in patients with otosclerosis.

SIGNIFICANCE

Our unique prosthesis yielded good outcomes for the treatment of otosclerosis even in the short term.

Pros and Cons of the Exoscope for Otologic Surgery

Introduction. There are a few discussions regarding usefulness of an exoscope in otologic surgery compared to a traditional microscope. Objective. The pros and cons of using a newly developed exoscope (ORBEYE™) during microotologic surgery were evaluated. Methods. The usefulness of the ORBEYE™ exoscope was retrospectively assessed in 6 otologic surgeries by 8 surgeons postoperatively. A questionnaire comprising 20 questions was designed and used for evaluation. Results. All the otologic surgeons agreed that the exoscope is useful as an educational tool; the exoscope had the highest score in the questionnaire (average: 4.75). The question "Will the ORBEYE^TM exoscope replace the conventional tympanoplasty or stapes surgery?" had the lowest score (average: 3.13). Conclusions. The quality of the images and movies in the exoscope was considered to be high and improved; therefore, the exoscope was considered as a useful educational tool in otologic surgery. Similar to otologic endoscopic surgery, all the members such as the operator and assistants could head up and share 1 image.

Clinical features of 22q11.2 deletion syndrome related to hearing and communication

Background: Individuals with 22q11.2 deletion syndrome (22q11.2DS) exhibit various phenotypes.Objective: To compare the clinical and otorhinolaryngological features of Japanese patients with 22q11.2DS with those of patients reported in Western literature.Materials and methods: We retrospectively assessed the medical records of 17 Japanese patients with 22q11.2DS and compared our findings with previously reported findings in Western literature.Results: Hearing loss was the most frequent complaint (n = 8, 47%), followed by articulation disorders and/or nasopharyngeal closure failure (n = 4, 24%) and language development delay (n = 2, 12%). Ten patients (59%) had hearing loss regardless of the chief complaint (total 15 ears - mild, 9; moderate, 6). Four patients had bilateral hearing loss. One patient (6%) underwent tympanostomy tube placement for refractory exudative otitis media, another (6%) underwent myringoplasty, and three patients (18%) underwent tympanoplasties for chronic otitis media or middle ear malformation. Previous studies in Western countries reported similar results in terms of frequency of hearing loss, severity of hearing loss, and the percentage of middle ear malformations.Conclusions: The otorhinolaryngological characteristics of Japanese patients with 22q11.2DS were similar to those in Western countries. Hearing loss was primarily caused by disorders like otitis media and middle ear malformation.Significance: Our findings may aid treatment planning for Asian patients with 22q11.2DS.

In Vivo Real-Time Simultaneous Examination of Drug Kinetics at Two Separate Locations Using Boron-Doped Diamond Microelectrodes

Methylcobalamin, which is used for the clinical treatment of patients with neuropathy, can have an impact on the sensorineural components associated with the cochlea, and it is possible that the auditory threshold in a certain population of patients with deafness may be recovered. Nonetheless, it remains uncertain whether the action site of methylcobalamin is localized inside or outside the cochlea and which cellular or tissue element is targeted by the drug. In the present work, we developed a method to realize in vivo real-time simultaneous examination of the drug kinetics in two separate locations using boron-doped diamond microelectrodes. First, the analytical performance of methylcobalamin was studied and the measurement protocol was optimized in vitro. Then, the optimized protocol was applied to carry out real-time measurements inside the cochlea and the leg muscle in live guinea pigs while systemically administering methylcobalamin. The results showed that the methylcobalamin concentration in the cochlea was below the limit of detection for the microelectrodes or the drug did not reach the cochlea, whereas the compound clearly reached the leg muscle.

Application of Mesenchymal Stem Cell Therapy and Inner Ear Regeneration for Hearing Loss: A Review

Inner and middle ear disorders are the leading cause of hearing loss, and are said to be among the greatest risk factors of dementia. The use of regenerative medicine for the treatment of inner ear disorders may offer a potential alternative to cochlear implants for hearing recovery. In this paper, we reviewed recent research and clinical applications in middle and inner ear regeneration and cell therapy. Recently, the mechanism of inner ear regeneration has gradually been elucidated. "Inner ear stem cells," which may be considered the precursors of various cells in the inner ear, have been discovered in the cochlea and vestibule. Research indicates that cells such as hair cells, neurons, and spiral ligaments may form promising targets for inner ear regenerative therapies by the transplantation of stem cells, including mesenchymal stem cells. In addition, it is necessary to develop tests for the clinical monitoring of cell transplantation. Real-time imaging techniques and hearing rehabilitation techniques are also being investigated, and cell therapy has found clinical application in cochlear implant techniques.

Acute onset olfactory/taste disorders are associated with a high viral burden in mild or asymptomatic SARS-CoV-2 infections

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Cycle threshold values were associated with the time to negative qPCR of SARS-CoV-2.

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Olfactory and taste disorders occurred after development of fever and sore throat.

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Fever and olfactory and taste disorders were correlated with higher viral burden.

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Assessment of olfactory and taste disorders may be important to prevent transmission.

This study investigated, using cycle threshold (Ct) qPCR values, the association between symptoms and viral clearance in 57 patients with asymptomatic/mild SARS-CoV-2 infection. Patients with olfactory/taste disorders (OTDs) exhibited lower qPCR Ct values and longer time to negative qPCR than those without OTDs, suggesting an association between OTDs and high viral burden.

How effect is educational counseling prior to middle ear surgery for patients with both middle ear diseases and consistent tinnitus?

Background: The management of patients with tinnitus who receive middle ear surgery has not been established.Aims: The aim of this study is (1) how many patients who receive middle ear surgery have tinnitus and (2) how educational counselling and middle ear surgery is effective with consistent tinnitus.Subjects and methods: Twenty four cases out of 90 cases accounted for 26.7% of the middle ear diseases scheduled for surgery in the past two years. Of the 42 patients with hearing loss in the second year, 14 had consistent and intermittent tinnitus. Among them we have 6 patients complaining consistent tinnitus and we examined the change in the Tinnitus Handicap Inventory (THI) for patients with tinnitus before and after surgery.Results: Ten out of 13 cases (about 76.9%) reported that postoperative tinnitus improved. THI score in two cases showed worse.Conclusions and significance: Two cases showed worse THI in both mixed hearing loss cases with a small hearing improvement. The mechanism of improvement is similar to tinnitus retraining therapy including hearing aid because the increase in external sound input through hearing restoration after surgery to avoid silence.

Comparison of inner ear drug availability of combined treatment with systemic or local drug injections alone

Combination of systemic and local drug therapy has been proved more effective and safer for idiopathic sudden sensorineural hearing loss by some clinical trials, and there are few laboratory researches on its pharmacokinetic behaviors in the inner ear. In the present study, we use a new in vivo imaging system to compare the pharmacokinetics of combined therapy (CT), with intravenous (IV) or transtympanic (TT) injection alone in both ears of transgenic GFAP-Luc mice. Biological half-life, total photon counts and the area under the curve (AUC) value significantly increased after CT. However, adding IV to TT injection cannot strengthen the peak photon of the drug in the inner ear. In addition, when D-luciferin is injected to the left ear the volume of total photon count and AUC value of CT-left ear are larger than the combined volume of TT-left ear and IV-left ear, suggesting a synergistic effect, and those of CT-right ear are almost equal to the summation of those of IV-right group and TT-right group, suggesting no amplifying effect on the risk of systemic side effect. This study showed that CT could deliver more drugs into the inner ear, and brought a longer therapeutic window, and were more effective than intravenous or transtympanic injection alone in the pharmacokinetics.

Development of intra-operative assessment system for ossicular mobility and middle ear transfer function

Objective measurements of the ossicular mobility have not been commonly performed during the surgery, and the assessment of ossicular mobility is made by palpation in most cases. Palpation is inherently subjective and may not always be reliable, especially in milder degrees of ossicular fixation and in the case of multiple fixation. Although several devices have been developed to quantitatively measure the ossicular mobility during surgery, they have not been widely used. In this study, a new system with a hand-held probe which enables intraoperative quantitative measurements of ossicular mobility has been developed. This system not only measures the ossicular mobility, but also investigates "local" transmission characteristics of the middle ear by directly applying vibration to the ossicles and measuring cochlear microphonic. The basic performance of this system was confirmed by measuring the mobility of artificial ossicles and cochlear microphonics in an animal experiment. Our system may contribute to selection of a better surgical method and reducing the risks of revision surgery.

Gene Delivery into the Inner Ear and Its Clinical Implications for Hearing and Balance

The inner ear contains many types of cell, including sensory hair cells and neurons. If these cells are damaged, they do not regenerate. Inner ear disorders have various etiologies. Some are related to aging or are idiopathic, as in sudden deafness. Others occur due to acoustic trauma, exposure to ototoxic drugs, viral infections, immune responses, or endolymphatic hydrops (Meniere's disease). For these disorders, inner ear regeneration therapy is expected to be a feasible alternative to cochlear implants for hearing recovery. Recently, the mechanisms underlying inner ear regeneration have been gradually clarified. Inner ear cell progenitors or stem cells have been identified. Factors necessary for regeneration have also been elucidated from the mechanism of hair cell generation. Inducing differentiation of endogenous stem cells or inner ear stem cell transplantation is expected. In this paper, we discuss recent approaches to hair cell proliferation and differentiation for inner ear regeneration. We discuss the future road map for clinical application. The therapies mentioned above require topical administration of transgenes or drug onto progenitors of sensory cells. Developing efficient and safe modes of administration is clinically important. In this regard, we also discuss our development of an inner ear endoscope to facilitate topical administration.

Approaches for Assessing Olfaction in Children with Autism Spectrum Disorder

Olfactory traits in individuals with autism spectrum disorder (ASD) are considered the strongest predictors of social impairment. Compared to other sensory abnormalities, olfactory abnormalities in individuals with ASD are poorly understood. In this chapter, we provide an overview of the current assessment in individuals with ASD. Several confounding factors have to be considered when conducting research on olfaction in individuals with ASD. Qualitative measures of olfaction contain only limited information about the olfactory stimuli. In addition, little systematic information is available about individual's actual uses of olfaction in daily life. Only a limited number of experimental studies have performed quantitative measurements of olfactory abnormalities in ASD. Therefore, clarifying the relationship between olfactory traits and the influence of real-life situations in a laboratory setting is very difficult. Some new methodologies for measuring olfactory traits are gradually becoming available. New methods that reveal important links between ASD and olfactory traits should be developed in the future.

Hearing Loss Controlled by Optogenetic Stimulation of Nonexcitable Nonglial Cells in the Cochlea of the Inner Ear

Light-gated ion channels and transporters have been applied to a broad array of excitable cells including neurons, cardiac myocytes, skeletal muscle cells and pancreatic β-cells in an organism to clarify their physiological and pathological roles. Nonetheless, among nonexcitable cells, only glial cells have been studied in vivo by this approach. Here, by optogenetic stimulation of a different nonexcitable cell type in the cochlea of the inner ear, we induce and control hearing loss. To our knowledge, deafness animal models using optogenetics have not yet been established. Analysis of transgenic mice expressing channelrhodopsin-2 (ChR2) induced by an oligodendrocyte-specific promoter identified this channel in nonglial cells—melanocytes—of an epithelial-like tissue in the cochlea. The membrane potential of these cells underlies a highly positive potential in a K⁺-rich extracellular solution, endolymph; this electrical property is essential for hearing. Illumination of the cochlea to activate ChR2 and depolarize the melanocytes significantly impaired hearing within a few minutes, accompanied by a reduction in the endolymphatic potential. After cessation of the illumination, the hearing thresholds and potential returned to baseline during several minutes. These responses were replicable multiple times. ChR2 was also expressed in cochlear glial cells surrounding the neuronal components, but slight neural activation caused by the optical stimulation was unlikely to be involved in the hearing impairment. The acute-onset, reversible and repeatable phenotype, which is inaccessible to conventional gene-targeting and pharmacological approaches, seems to at least partially resemble the symptom in a population of patients with sensorineural hearing loss. Taken together, this mouse line may not only broaden applications of optogenetics but also contribute to the progress of translational research on deafness.

Assessment of hyperacusis with a newly produced Japanese version of the Khalfa hyperacusis questionnaire

OBJECTIVES

The purpose of this study was to determine the validity and reliability of a Japanese version of the Khalfa hyperacusis questionnaire (KHQ) and proposed a threshold KHQ score for classifying hyperacusis.

METHODS

In total, 112 patients with hyperacusis (group A) and 103 patients without hyperacusis (group B). The patients in group A were further classified into the following subgroups: subjects with hyperacusis as their chief complaint (n = 26, group A1) and subjects with hyperacusis accompanied by chief complaints of tinnitus and/or hearing loss (n = 86, group A2).

RESULTS

The average total questionnaire score for patients in group A was 11.8 ± 9.7, which was statistically significantly higher than that of patients in group B, 5.7 ± 4.8. Cronbach's coefficients for internal consistency were high for the total score (0.92). The average total scores for groups A1 and A2 were 18.1 ± 11.1 and 9.9 ± 8.4, respectively, and the difference between the groups was statistically significant.

CONCLUSIONS

We developed a Japanese version of the KHQ. It showed high reliability and validity; suggesting its usefulness in clinical practice. We propose that a total KHQ score of 16 is an appropriate cutoff for classifying hyperacusis.

Nationwide epidemiological survey of idiopathic sudden sensorineural hearing loss in Japan

OBJECTIVES

Using a large-scale nationwide survey database, we investigated the epidemiological characteristics for idiopathic SSNHL in Japan.

METHODS

The subjects for this analysis were patients registered in a Japanese multicentre database between April 2014 and March 2016. A total of 3419 idiopathic SSNHL patients were registered in the database, and the clinical characteristics of the idiopathic SSNHL patients were obtained. Several factors associated with the severity of hearing impairment and prognosis were then investigated. Statistical analysis was performed to clarify the factors associated with the severity of hearing impairment and prognosis.

RESULTS

There were significant correlations between the severity of hearing loss and diabetes mellitus, kidney disease, past history of brain infarction, heart disease, age (under 16 years/elderly), and symptoms of vertigo/dizziness. We also analyzed the prognostic factors for idiopathic SSNHL, and found that the severity of hearing loss (Grade 3 or 4), heart disease, aged 65 years or over, time from onset to treatment (over 7 days), and symptoms of vertigo/dizziness were all significantly related to poor prognosis.

CONCLUSION

The present large-scale clinical survey revealed current epidemiological trends for idiopathic sudden sensorineural hearing loss (SSNHL) and various factors associated with the severity of hearing impairment and prognosis.

FUT2 non-secretor status is associated with Type 1 diabetes susceptibility in Japanese children

AIM

To examine the contribution of the FUT2 gene and ABO blood type to the development of Type 1 diabetes in Japanese children.

METHODS

We analysed FUT2 variants and ABO genotypes in a total of 531 Japanese children diagnosed with Type 1 diabetes and 448 control subjects. The possible association of FUT2 variants and ABO genotypes with the onset of Type 1 diabetes was statistically examined.

RESULTS

The se2 genotype (c.385A>T) of the FUT2 gene was found to confer susceptibility to Type 1A diabetes in a recessive effects model [odds ratio for se2/se2, 1.68 (95% CI 1.20-2.35); corrected P value = 0.0075].

CONCLUSIONS

The FUT2 gene contributed to the development of Type 1 diabetes in the present cohort of Japanese children.

Idiopathic sudden sensorineural hearing loss and acute low-tone sensorineural hearing loss: a comparison of the results of a nationwide epidemiological survey in Japan

OBJECTIVES

The aim of this study was to investigate the differences between idiopathic sudden sensorineural hearing loss (SSNHL), and acute low-tone sensorineural hearing loss (ALHL) using the results of a nationwide survey database in Japan and to analyze the variables associated with their clinical features and the severity of hearing impairment, treatment, and prognosis.

METHODS

Participants were patients registered between April 2014 and March 2016 in a multicenter epidemiological survey database involving 30 university hospitals and medical centers across Japan. Statistical analysis was performed to clarify the factors associated with their clinical characteristics and the severity of hearing impairment, treatment, and prognosis.

RESULTS

Idiopathic SSNHL and ALHL differed significantly in terms of male-to-female ratio, age distribution, and time from onset to start of treatment. The treatment methods and hearing prognosis also differed markedly between the two diseases. A majority (92%) of idiopathic SSNHL patients were administered some type of corticosteroid, while half of the ALHL patients received corticosteroids and a diuretic agent.

CONCLUSION

The results suggested that idiopathic SSNHL and ALHL belonged to different categories of inner ear disease.

The effect of initial treatment on hearing prognosis in idiopathic sudden sensorineural hearing loss: a nationwide survey in Japan

OBJECTIVE

To investigate the hearing prognosis of idiopathic sudden sensorineural hearing loss (SSNHL) treated with different initial therapies.

METHODS

Subjects consisted of patients diagnosed with idiopathic SSNHL within 7 days from onset and showing severe hearing loss (≥60 dB), who were registered in a Japanese multicenter database between April 2014 and March 2016. Subjects were divided into four groups according to initial therapy: (1) steroids, (2) steroids + Prostaglandins (PGs), (3) intratympanic steroids (ITS), and (4) no steroids. Hearing outcomes were compared among the groups.

RESULTS

In total, 1305 patients were enrolled. The final hearing level and hearing gain of patients treated with steroids + PGs were significantly higher than those of patients treated with steroids alone or no steroids. The ratio of good prognosis (complete recovery or marked improvement) in patients treated with steroids + PGs was higher than that in patients treated with steroids alone or no steroids. There was no difference in the prognosis of patients treated with steroids alone or no steroids.

CONCLUSION

A large number of patients with idiopathic SSNHL were registered in a multicenter database. PG use in combination with steroid administration was associated with a good hearing prognosis in patients with severe hearing loss.

Hochuekkito, a Japanese Herbal Medicine, Restores Metabolic Homeostasis between Mitochondrial and Glycolytic Pathways Impaired by Influenza A Virus Infection

BACKGROUND

Hochuekkito (HKT), a traditional Japanese herbal medicine (Kampo), has been used to treat symptoms of several diseases. In a recent clinical study, HKT was shown to be protective against the influenza virus infection. However, the underlying mechanism of the prophylactic effect is not clear. Mitochondrial and glycolytic pathways play important roles in cellular energy metabolism to maintain biological functions. These metabolic pathways are affected by the influenza virus infection. In this study, we examined the relationship between the preventive effects of HKT against the influenza virus infection and cellular energy metabolism in mitochondria and glycolysis using Madin-Darby canine kidney cells and influenza A/PR/8/34 (H1N1) virus (IAV).

METHODS

Mitochondrial and glycolytic metabolic pathways were evaluated on the basis of the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), respectively, using the XF24 Extracellular Analyzer.

RESULTS

The OCR/ECAR ratio in IAV-infected cells was lower than that in control cells. Cells that were treated with HKT before IAV infection showed a metabolic pattern similar to that in the control cells (increase in both OCR and ECAR).

CONCLUSIONS

Our results suggest that HKT not only activates both mitochondrial and glycolytic energy metabolism in IAV-infected cells but also helps maintain metabolic homeostasis similar to that in noninfected cells.

Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis

In most mammals, auditory ossicles in the middle ear, including the malleus, incus and stapes, are the smallest bones. In mice, a bony structure called the auditory bulla houses the ossicles, whereas the auditory capsule encloses the inner ear, namely the cochlea and semicircular canals. Murine ossicles are essential for hearing and thus of great interest to researchers in the field of otolaryngology, but their metabolism, development, and evolution are highly relevant to other fields. Altered bone metabolism can affect hearing function in adult mice, and various gene-deficient mice show changes in morphogenesis of auditory ossicles in utero. Although murine auditory ossicles are tiny, their manipulation is feasible if one understands their anatomical orientation and 3D structure. Here, we describe how to dissect the auditory bulla and capsule of postnatal mice and then isolate individual ossicles by removing part of the bulla. We also discuss how to embed the bulla and capsule in different orientations to generate paraffin or frozen sections suitable for preparation of longitudinal, horizontal, or frontal sections of the malleus. Finally, we enumerate anatomical differences between mouse and human auditory ossicles. These methods would be useful in analyzing pathological, developmental and evolutionary aspects of auditory ossicles and the middle ear in mice.

Variants associated with autoimmune Type 1 diabetes in Japanese children: implications for age-specific effects of cis-regulatory haplotypes at 17q12-q21

AIMS

The aim of this study was to clarify the significance of previously reported susceptibility variants in the development of autoimmune Type 1 diabetes in non-white children. Tested variants included rs2290400, which has been linked to Type 1 diabetes only in one study on white people. Haplotypes at 17q12-q21 encompassing rs2290400 are known to determine the susceptibility of early-onset asthma by affecting the expression of flanking genes.

METHODS

We genotyped 63 variants in 428 Japanese people with childhood-onset autoimmune Type 1 diabetes and 457 individuals without diabetes. Possible association between variants and age at diabetes onset was examined using age-specific quantitative trait locus analysis and ordered-subset regression analysis.

RESULTS

Ten variants, including rs2290400 in GSDMB, were more frequent among the people with Type 1 diabetes than those without diabetes. Of these, rs689 in INS and rs231775 in CTLA4 yielded particularly high odds ratios of 5.58 (corrected P value 0.001; 95% CI 2.15-14.47) and 1.64 (corrected P value 5.3 × 10^-5 ; 95% CI 1.34-2.01), respectively. Age-specific effects on diabetes susceptibility were suggested for rs2290400; heterozygosity of the risk alleles was associated with relatively early onset of diabetes, and the allele was linked to the phenotype exclusively in the subgroup of age at onset ≤ 5.0 years.

CONCLUSIONS

The results indicate that rs2290400 in GSDMB and polymorphisms in INS and CTLA4 are associated with the risk of Type 1 diabetes in Japanese children. Importantly, cis-regulatory haplotypes at 17q12-q21 encompassing rs2290400 probably determine the risk of autoimmune Type 1 diabetes predominantly in early childhood.

The Preventive Effect of the Traditional Japanese Herbal Medicine, Hochuekkito, against Influenza A Virus via Autophagy in vitro

BACKGROUND

Hochuekkito (HKT), a traditional Japanese herbal medicine, enhances the immunity of elderly or weak individuals. It is also known to have preventive effects against influenza clinically. However, the detailed mechanisms of the preventive effects have not been clarified. We examined the relationship between the preventive effects of HKT and autophagy, a known stress response and quality control mechanism, using Madin-Darby canine kidney cells and influenza A/PR/8/34 (H1N1) virus.

METHODS

The effect of HKT on autophagy in influenza A virus (IAV)-infected cells was assessed by Western blotting and fluorescence microscopy using an RFP-GFP-LC3B sensor kit.

RESULTS

In Western blotting, treatment with HKT before IAV infection (pre-HKT) tended to induce autophagy in IAV-infected cells at an early stage of infection, eventually suppressing IAV-induced autophagy. Moreover, several autolysosomes, indicative of normal autophagosome-lysosome fusion, were observed in Pre-HKT cells transduced with RFP-GFP-LC3B but not in untreated IAV-infected cells.

CONCLUSIONS

These findings indicated that IAV-mediated inhibition of the fusion of autophagosomes with lysosomes was prevented by HKT treatment before infection. According to these results, we propose that this phenomenon is one of the preventive effects of HKT against IAV.

Tympanoplasty for chondrodysplasia punctata: Case report

Chondrodysplasia punctata (CP) is a systemic disorder of chondrogenesis. The most prominent features of patients with CP are abnormal faces characterized by a flat nose and short stature. CP patients show various types and levels of hearing loss. This disease is rare, and no successful tympanoplasties with hearing recovery have been reported. Here, we report on a CP case, in which hearing recovery was successfully treated with tympanoplasty.

Sustained Effect of Hyaluronic Acid in Subcutaneous Administration to the Cochlear Spiral Ganglion

The spatiotemporal distribution of drugs in the inner ear cannot be precisely evaluated because of its small area and complex structure. In the present study, we used hyaluronic acid (HA)-dispersed luciferin to image transgenic mice and to determine the effect of HA on controlled drug delivery to the cochlea. GFAP-luc mice, which express luciferase in cochlear spiral ganglion cells, were subcutaneously administered HA-luciferin (HA-sc) or luciferin dissolved in saline (NS-sc) or intraperitoneally administered luciferin dissolved in saline (NS-ip). The bioluminescence of luciferin was monitored in vivo in real time. The peak time and half-life of fluorescence emission were significantly increased in HA-sc-treated mice compared with those in NS-sc- and NS-ip-treated mice; however, significant differences were not observed in peak photon counts. We detected differences in the pharmacokinetics of luciferin in the inner ear, including its sustained release, in the presence of HA. The results indicate the clinical potential of using HA for controlled drug delivery to the cochlea.

[Evaluation of the Effectiveness and Safety in a Multi-center Clinical Trial of VIBRANT SOUNDBRIDGE in Japan]

Middle ear implants (MEIs) such as the Vibrant Soundbridge (VSB) are attractive and alternative treatments for patients with conductive, sensorineural, and mixed hearing loss who do not benefit from, or who choose not to wear, conventional hearing aids (HAs). Recent studies suggest that MEIs can provide better improvements in functional gain, speech perception, and quality of life than HAs, although there are certain risks associated with the surgery which should be taken into consideration, including facial nerve or chorda tympanic nerve damage, dysfunctions of the middle and inner ears, and future device failure/explantation. In Japan, a multi-center clinical trial of VSB was conducted between 2011-2014. A round window vibroplasty via the transmastoid approach was adopted in the protocol. The bony lip overhanging the round window membrane (RWM) was extensively but very carefully drilled to introduce the Floating Mass Transducer (FMT). Perichondrium sheets were used to stabilize the FMT onto the RWM. According to the audiological criteria, the upper limit of bone conduction should be 45 dB, 50 dB, and 65 dB from 500 Hz to 4, 000 Hz. Twenty-five patients underwent the surgery so far at 13 different medical centers. The age at the surgery was between 26-79 years old, and there were 15 males and 10 females. The cause of conductive or mixed hearing loss was middle ear diseases in 23 cases and congenital aural atresia in two cases. The data concerning on the effectiveness and safety of VSB was collected before the surgery and 20 weeks after the surgery. Significant improvements of free-field Pure Tone Audiogram (PTA) from 250 Hz to 8, 000 Hz were confirmed (p < 0.001). Hearing gain up to 40 dB was achieved in the 1, 000 Hz to 4, 000 Hz range. No deterioration in either air conduction or bone conduction at PTA was noted at 20 weeks after the surgery. Monosyllable speech perception in both quiet and noisy conditions improved significantly (p < 0.001). The speech discrimination score in both quiet and noisy conditions improved significantly too (p < 0.001). In the future, it is likely that there will be an increasing population even in Japan that will meet the criteria for MEIs such as VSB. However, the long-term efficacy and safety of these devices should be established.

The effects of cochlear implantation in Japanese single-sided deafness patients: five case reports

CONCLUSION

Cochlear implantation (CI) for Japanese single-sided deafness patients resulted in improved speech perception, increased sound localization accuracy, and reduced tinnitus handicap.

OBJECTIVES

This study reports results for five adult SSD cases with CI, focusing on the benefits they obtained in terms of speech recognition, sound localization, and tinnitus handicap.

METHODS

Five Japanese patients meeting the eligibility criteria were included in this study. All patients were implanted with a fully inserted MED-EL Concerto FLEX28® implant (MED-EL, Innsbruck, Austria). Speech perception outcomes in noise, as well as sound localization and tinnitus disturbance, were assessed pre-surgically and at 1, 3, 6, and 12 months after CI activation.

RESULTS

The Japanese monosyllable test score in noise improved gradually after implantation. In some cases, speech perception ability appeared unstable, particularly in the first 1-6 months after implantation. The sound localization ability showed marked improvement in all cases, with the disturbance to daily life caused by tinnitus also decreasing in all cases from the early post-operative period.

[Multicenter Clinical Study of Vibrant Soundbridge in Japan: Analysis of Subjective Questionnaires]

The Vibrant Soundbridge (VSB) is an active middle ear implant with the Floating Mass Transducer (FMT). We performed a multicenter study to study the efficacy of the VSB by means of "the 10 Questionnaire on Hearing 2002" and "the APHAB questionnaire" at 13 hospitals between 2011 and 2013. In all, 23 patients with mixed or conductive hearing loss received VSB implantation by the round window placement technique. These individuals were generally unable to use, or gained little from conventional hearing aids or bone conduction hearing aids. Two questionnaires were administrated before the surgery and 20 weeks after the VSB implantation. Scores on every item of "the 10 Questionnaire on Hearing 2002" showed significant improvement under noise after VSB implantation. On the APHAB, the scores for Ease of Communication, Reverberation, and Background subscales improved significantly after the VSB implantation, while the score for the Aversiveness subscale alone failed to show a positive improvement from the inexperience to the new sound. Analysis of the responses to these subjective questionnaires revealed better results after VSB implantation as compared to the preoperative data. In conclusion, RW vibroplasty with the use of VSB provided subjective benefit in patients with conductive and mixed hearing loss.

Autophagy through 4EBP1 and AMPK regulates oxidative stress-induced premature senescence in auditory cells

The aim of this study was to determine whether autophagy and AMPK contribute to premature senescence in auditory cells. Incubating HEI-OC1 auditory cells with 5 mM H2O2 for 1 h induced senescence, as demonstrated by senescence-associated β-galactosidase (SA-β-gal) staining. H2O2 treatment significantly delayed population-doubling time, leaving cell viability unchanged. Furthermore, the proportion of SA-β-gal-positive cells significantly increased. Autophagy-related protein expression increased, with Atg7 and LC3-II peaking 6 h and Lamp2 peaking 24 h after H2O2 treatment. The expression of these proteins decreased 48 h after treatment. Transmission electron microscopy revealed lipofuscin and aggregates within autolysosomes, which accumulated markedly in the cytoplasm of HEI-OC1 cells 48 h after treatment. Akt and P70S6 phosphorylation markedly decreased after H2O2 treatment, but 4EBP1 phosphorylation significantly increased 48 h after treatment. After RNAi-mediated knockdown (KD) of Atg7 and AMPK, H2O2-treated cells displayed dense SA-β-gal staining. Also, premature senescence was significantly induced. These suggest that a negative feedback loop may exist between autophagy and AMPK signaling pathways in HEI-OC1 cells. In our model, oxidative stress-induced premature senescence occurred due to impaired autophagy function through 4EBP1 phosphorylation. Our results also indicate that AMPK may regulate premature senescence in auditory cells in an autophagy-dependent and independent manner.

Histamine antagonist Bepotastine suppresses nasal symptoms caused by Japanese cedar and cypress pollen exposure

Objective: To determine the efficacy of the antihistamine bepotastine on treating nasal symptoms in patients with Japanese cedar and cypress pollinosis, based on two previous studies that looked at bepotastine OD’s inhibitory effect on symptom onset after exposure.

Design and methods: Randomized double-blind placebo controlled, parallel study. Twenty-eight volunteers with Japanese cedar and cypress pollinosis were randomly assigned into two experimental groups: a bepotastine-treated or a placebo control group. Subjects received either 10 mg bepotastine tablets or placebo tablets 1 day before entering an artificial exposure pollen chamber (OHIO Chamber) and also for three or more consecutive days. They were exposed to Japanese cedar and cypress pollen for 3 h per day for 2 days. Nasal and ocular symptoms were self-rated by each patient at regular intervals in addition to being objectively measured. Possible cognitive impairment was assessed by using the digit cancellation test (D-CAT).

Results: In Study 1, under controlled conditions, there were no significant differences (p > .05) between subjects exposed to Japanese cedar pollen and those exposed to cypress pollen in terms of total nasal symptom score (TNSS).

In Study 2, in the placebo group, the amount of nasal discharge and the number of sneezes did not diminish before cypress pollen exposure on the second day (p < .05). This suggests that an antihistamine can suppress the symptoms of hang over. No deterioration of work performance was observed in the bepotastine group after pollen exposure for 2 days, as measured by D-CAT (p > .05).

Conclusion: We conclude that bepotastine can suppress allergy-related symptoms without impairing work performance in subjects with seasonal allergic rhinitis caused by Japanese cedar pollen or cypress pollen.

Novel in vivo imaging analysis of an inner ear drug delivery system: Drug availability in inner ear following different dose of systemic drug injections

Systemic application of drugs is commonly used in clinical situations. Some of these drugs are ototoxic. Since there are few studies on in vivo monitoring of drug delivery dynamics, the time course or bioavailability of drugs in the inner ear of live animals following systemic drug application remains unknown. For instance, it is unknown whether the volume of a drug delivered systemically correlates with its inner ear pharmacokinetics. We previously established a new in vivo imaging system to monitor drug delivery in live mice. In the present study, we used this system to compare drug concentration in the inner ear over time after systemic drug injections. We used transgenic GFAP-Luc mice that harbor a firefly luciferase gene expression cassette regulated by 12 kb of murine GFAP promoter and human beta-globin intron 2. Luciferin delivered into the inner ear of these mice reacts with luciferase, and the resulting signals are detected in GFAP-expressing cells in the cochlear nerve. Thus, we assessed in the inner ear the intensity and duration of luciferin/luciferase signals after systemic injections of different volumes of luciferin. An IVIS(®) imaging system was used to observe signals, and these signals were compared to the drug dynamics of luciferin delivered through subcutaneous (sc) injections. The volume of sc-injected drug correlated significantly with photon counts measured in the inner ear. Photons were detected almost immediately after injection, peaking 20 min after injection. Drug concentration did not affect inner ear signals. Luciferin injected systemically appeared in the inner ear between highest and lowest concentration. Drug volume is an important parameter to know if the inner ear requires a higher level of the drug. We observed that it is the volume of a drug-not its concentration-that is the important factor. Indeed, the more volume of a drug injected systemically increased the concentration of that drug in the inner ear. This study provides a better understanding of in vivo drug delivery dynamics measured in the inner ear. Further studies will show whether a high dosage of drug is effective or not.

The autophagy pathway maintained signaling crosstalk with the Keap1-Nrf2 system through p62 in auditory cells under oxidative stress

The main purposes of our study were to consider the effect of autophagy on auditory cells under oxidative stress, and the function of possible crosstalk among p62, Keap1 and Nrf2 in autophagy-deficient auditory cells. First, we described how cell death was induced in auditory cell line (HEI-OC1) exposed to H2O2. We found that the decision for the cell death of auditory cells under oxidative stress depends on the balance between autophagy and necrosis due to ATP depletion, and autophagy plays a cytoprotective function in oxidative stress-induced necrosis. Our data clearly suggested that autophagy was a cell survival mechanism in H2O2-induced cell death, based on the observation that suppression of autophagy by knockdown of Atg7 sensitized, whereas activation of autophagy by rapamycin protected against H2O2-induced cell death. Next, our results regarding the relationship among p62, Nrf2 and Keap1 by siRNA paradoxically showed that p62 creates a positive feedback loop in the Keap1/Nrf2 pathway. Autophagy impaired by Atg7 knockdown degrades Keap1 in a p62-dependent manner, whereas Nrf2 is activated. As a result, the cell death induced by H2O2 was promoted in auditory cells. Taken together, these results suggested that the autophagy pathway maintained signaling crosstalk with the Keap1-Nrf2 system through p62 in auditory cells under oxidative stress.

Magnetic resonance monitoring of superparamagnetic iron oxide (SPIO)-labeled stem cells transplanted into the inner ear

In the field of regenerative medicine, cell transplantation or cell-based therapies for inner ear defects are considered to be promising candidates for a therapeutic strategy. In this paper, we report on a study that examined the use of magnetic resonance imaging (MRI) to monitor stem cells transplanted into the cochlea labeled with superparamagnetic iron oxide (SPIO), a contrast agent commonly used with MRI. First, we demonstrated in vitro that stem cells efficiently took up SPIO particles. This was confirmed by Prussian blue staining and TEM. In MRI studies, T2 relaxation times of SPIO-labeled cells decreased in a dose-dependent manner. Next, we transplanted SPIO-labeled cells directly into the cochlea in vivo and then performed MRI 1h, 2 weeks, and 4 weeks after transplantation. The images were evaluated objectively by measuring signal intensity (SI). SI within the ears receiving transplants was significantly lower (P<0.05) than that of control sides at the 1-h assessment. This novel method will be helpful for evaluating stem cell therapies, which represents a new strategy for inner ear regeneration. To the best of our knowledge, this study is the first to demonstrate that local transplantation of labeled stem cells into the inner ear can be visualized in vivo via MRI.

Neuroprotective effects of cutamesine, a ligand of the sigma-1 receptor chaperone, against noise-induced hearing loss

The sigma-1 receptor, which is expressed throughout the brain, provides physiological benefits that include higher brain function. The sigma-1 receptor functions as a chaperone in the endoplasmic reticulum and may control cell death and regeneration within the central nervous system. Cutamesine (1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl) piperazine dihydrochloride) is a ligand selective for this receptor and may mediate neuroprotective effects in the context of neurodegenerative disease. We therefore assessed whether cutamesine protects the inner ear from noise-induced or aging-associated hearing loss. Immunohistochemistry and Western blotting revealed that the sigma-1 receptor is present in adult cochlea. We treated mice with 0, 3, or 30 mg/kg cutamesine from 10 days before noise exposure until the end of the study. All subjects were exposed to a 120-dB, 4-kHz octave-band noise for 2 hr. We assessed auditory thresholds by measuring the auditory-evoked brainstem responses at 4, 8, and 16 kHz, prior to and 1 week, 1 month, or 3 months following noise exposure. For the aging study, measurements were made before treatment was initiated and after 3 or 9 months of cutamesine treatment. Damage to fibrocytes within the cochlear spiral limbus was assessed by quantitative histology. Cutamesine significantly reduced threshold shifts and cell death within the spiral limbus in response to intense noise. These effects were not dose or time dependent. Conversely, cutamesine did not prevent aging-associated hearing loss. These results suggest that cutamesine reduces noise-induced hearing loss and cochlear damage during the acute phase that follows exposure to an intense noise.

Gene and drug delivery system and potential treatment into inner ear for protection and regeneration

The most common type of hearing loss results from damage to the cochlea including lost hair cells (HCs) and spiral ganglion neurons (SGNs). In mammals, cochlear HC loss causes irreversible hearing impairment because this type of sensory cell cannot regenerate. The protection from SGN from degeneration has implications for cochlear implant to patients with severe deafness. This review summarizes the several treatments for HC regeneration based on experiments. We discuss how transgene expression of the neurotrophic factor can protect SGN from degeneration and describe potential new therapeutic interventions to reduce hearing loss. We also summarized viral vectors and introduced the gene and drug delivery system for regeneration and protection of cochlear HCs. Finally, we introduce the novel endoscopy we developed for local injection into cochlea.

Molecular Network of Tinnitus Focusing on BDNF Signal and Autophagy in Auditory Cells

Objectives:

Recent studies show that the expression of brain-derived neurotrophic factor (BDNF) is decreasing in patients with depression and severe tinnitus. However, the relationship between the incidence of tinnitus and the role of BDNF remains unclear in auditory cells. The aim of this study is to consider the molecular network of tinnitus focusing on BDNF signal and autophagy in auditory cells.

Methods:

We used auditory cell line (HEI-OC1) in this study. Tunicamycin was used as endoplasmic reticulum (ER) stress. The viability of HEI-OC1 was determined by cell viability assays. Morphological observation was performed under transmission electron microscope (TEM). Western blot analysis was performed.

Results:

The cell viability after treatment of tunicamycin was decreased in dose- and time-dependent matter. Autophagosomes and autolysososmes were confirmed into the cytoplasm of HEI-OC1 under TEM. The expression of LC3-II was increased in HEI-OC1 after treatment of tunicamycin. These results mean that autophagy was consistently induced in tunicamycin-treated cells. The expression of CHOP was decreased after peaking at 12 hours after the treatment of tunicamycin. The expression of BDNF, which has the potential to become a biomarker of tinnitus, and calcium-dependent activator protein for secretion 2 (CAPS2) that promotes BDNF section, were decreased in tunicamycin-treated cells. The expression of Bcl-2 that control apoptosis and Beclin1 that regulate autophagy were decreased in tunicamycin-treated cells.

Conclusions:

Our results lead to the suggestion that the autophagy-mediated regulation of cell death and molecular network focusing on BDNF signal play a major part of the incidence of tinnitus.

The Effect of Controlled-Release Hyaluronic Acid on Drug Delivery to the Cochlear Spiral Ganglion

Objectives:

The spatiotemporal distribution of drugs in the inner ear has not fully been characterized because of the area’s small size and complicated compartments. In the present study, we investigate the pharmacokinetics of a small molecule conjugated with different amounts of carrier in the cochlea by using transgenic technology and the IVIS Imaging System.

Methods:

Luciferin, a 280 MW substrate of luciferase, was conjugated with different MW of hyaluronic acid and was subcutaneously administered to the transgenic mouse, GFAP-luc, which expresses luciferase specifically in the cochlear spiral ganglion cells. Bioluminescence produced by a chemical reaction of luciferin-luciferase was monitored using the Xenogen-IVIS 100.

Results:

The peak photon count decreased dose-dependently on the MW of hyaluronic acid, whereas the duration was prolonged.

Conclusions:

Our imaging system successfully detected differences in the pharmacokinetics of luciferin in the inner ear. The sustained-release effect of hyaluronic acid was observed and differed by its MW. The result suggests the clinical significance of hyaluronic acid for controlling drug delivery to the cochlea.

High fibrinogen in peripheral blood correlates with poorer hearing recovery in idiopathic sudden sensorineural hearing loss

Objectives

We used hearing tests and peripheral blood sample analyses to characterize the pathology of idiopathic sudden sensorineural hearing loss (ISSNHL) and to identify possible prognostic factors for predicting recovery of hearing loss.

Study Design

A retrospective, multicenter trial was conducted.

Methods

Two hundred three patients examined within 7 days after the onset of ISSNHL received prednisone with lipo-prostaglandin E1. Pure-tone auditory tests were performed before and after treatment with these drugs. Blood tests were performed on blood samples collected during the patients’ initial visit to our clinic.

Results

In all patients, elevated white blood cell (WBC) counts, fasting blood sugar levels, HgbA1c, and erythrocyte sedimentation rate (ESR) significantly correlated with high hearing threshold measurements obtained on the initial visit. High fibrinogen levels, WBC counts, ESR, and low concentrations of fibrinogen degradation products (FDP) were associated with lower hearing recovery rates. Additionally, different audiogram shapes correlated with different blood test factors, indicating that different pathologies were involved.

Conclusions

High fibrinogen levels measured within seven days after ISSNHL onset correlated with poorer hearing recovery. This may be a consequence of ischemia or infections in the inner ear. The high WBC counts also observed may therefore reflect an immune response to inner ear damage induced by ischemic changes or infections. Our data indicate that therapeutic strategies should be selected based on the timing of initial treatment relative to ISSNHL onset.