Lipid metabolism and hearing loss: association of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) with adolescent hearing health.

Background: The ratio of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol (NHHR) is a novel lipid measure for assessing the risk of cardiovascular disease. Lipid metabolism disorders are reportedly associated with hearing impairment. This study aimed to investigate the potential association between NHHR and hearing.

Clinical insights into tuberculosis otitis media: diagnosis, treatment, and management outcomes.

Objectives: The diagnosis of tuberculosis otitis media (TBOM) remains a great challenge. This study aims to suggest potential diagnostic clues and proper management of TBOM.

Methods: The study is a retrospective review of TBOM cases that were treated at our department, between January 2015 and June 2023.

ROS-induced oxidative stress and mitochondrial dysfunction: a possible mechanism responsible for noise-induced ribbon synaptic damage.

Evidence suggests that damage to the ribbon synapses (RS) may be the main cause of auditory dysfunction in noise-induced hearing loss (NIHL). Oxidative stress is implicated in the pathophysiology of synaptic damage. However, the relationship between oxidative stress and RS damage in NIHL remains unclear.

Co-transduction of dual-adeno-associated virus vectors in the neonatal and adult mouse utricles.

Adeno-associated virus (AAV)-mediated gene transfer is an efficient method of gene over-expression in the vestibular end organs. However, AAV has limited usefulness for delivering a large gene, or multiple genes, due to its small packaging capacity (< 5 kb). Co-transduction of dual-AAV vectors can be used to increase the packaging capacity for gene delivery to various organs and tissues.

Mutation of SLC7A14 causes auditory neuropathy and retinitis pigmentosa mediated by lysosomal dysfunction.

Lysosomes contribute to cellular homeostasis via processes including macromolecule degradation, nutrient sensing, and autophagy. Defective proteins related to lysosomal macromolecule catabolism are known to cause a range of lysosomal storage diseases; however, it is unclear whether mutations in proteins involved in homeostatic nutrient sensing mechanisms cause syndromic sensory disease. Here, we show that SLC7A14, a transporter protein mediating lysosomal uptake of cationic amino acids, is evolutionarily conserved in vertebrate mechanosensory hair cells and highly expressed in lysosomes of mammalian cochlear inner hair cells (IHCs) and retinal photoreceptors.

Epithelial-Mesenchymal Transition Participates in the Formation of Vestibular Flat Epithelium.

The vestibular sensory epithelium of humans and mice may degenerate into a layer of flat cells, known as flat epithelium (FE), after a severe lesion. However, the pathogenesis of vestibular FE remains unclear. To determine whether the epithelial-mesenchymal transition (EMT) participates in the formation of vestibular FE, we used a well-established mouse model in which FE was induced in the utricle by an injection of streptomycin into the inner ear.

Diploic vein as a newly treatable cause of pulsatile tinnitus: A case report.

Background: Pulsatile tinnitus (PT) is an annoying sound that can be eliminated with targeted treatment of the cause. However, the causes of PT have not been fully elucidated.

Case Summary: A 38-year-old woman with right-sided objective PT underwent preoperative computed tomography arteriography and venography (CTA/V).

Bone remodeling in sigmoid sinus diverticulum after stenting for transverse sinus stenosis in pulsatile tinnitus: A case report.

Background: Pulsatile tinnitus (PT) is a potentially disabling symptom that has received increasing attention. Multiple causes of PT have been confirmed by targeted treatment. However, dynamic changes of related structures in PT patients with multiple causes after stenting for ipsilateral transverse sinus stenosis (TSS) have not been previously reported.

AAV8-mediated Atoh1 overexpression induces dose-dependent regeneration of vestibular hair cells in adult mice.

Vestibular hair cells (HCs) are mechanoreceptors for the detection of head movement. Vestibular HCs of adult mammals never completely regenerate after damage, resulting in vestibular dysfunction. Overexpression of Atoh1 is effective for inducing HC regeneration.

Loss of Cochlear Ribbon Synapse Is a Critical Contributor to Chronic Salicylate Sodium Treatment-Induced Tinnitus without Change Hearing Threshold.

Tinnitus is a common auditory disease worldwide; it is estimated that more than 10% of all individuals experience this hearing disorder during their lifetime. Tinnitus is sometimes accompanied by hearing loss. However, hearing loss is not acquired in some other tinnitus generations.

Suggestion of a Modified Classification for Congenital Middle Ear Cholesteatoma: Based on the Clinical Characteristics and Staging of Fifty-Seven Patients.

To explore more refined classification methods of congenital middle ear cholesteatoma (CMEC) based on two existing staging systems. This study involved a retrospective data review of 57 patients (61 ears involved) with CMEC requiring the surgical treatment. Patients were classified into different stages according to Nelson, Potsic, and Modified Nelson staging system.

Cellular origin and response of flat epithelium in the vestibular end organs of mice to Atoh1 overexpression.

A flat epithelium (FE) may be found in the vestibular end organs of humans and mice with vestibular dysfunction. However, the pathogenesis of FE is unclear and inducing hair cell (HC) regeneration is challenging, as both HCs and supporting cells (SCs) in vestibular FE are damaged. To determine the cellular origin of vestibular FE and examine its response to Atoh1 overexpression, we fate-mapped vestibular epithelial cells in three transgenic mouse lines (vGlut3-iCreER:Rosa26, GLAST-CreER:Rosa26, and Plp-CreER:Rosa26) after inducing a lesion by administering a high dose of streptomycin.

RNA-seq Profiling and Co-expression Network Analysis of Long Noncoding RNAs and mRNAs Reveal Novel Pathogenesis of Noise-induced Hidden Hearing Loss.

Noise-induced hidden hearing loss (NIHHL), one of the family of conditions described as noise-induced hearing loss (NIHL), is characterized by synaptopathy following moderate noise exposure that causes only temporary threshold elevation. Long noncoding RNAs (lncRNAs) mediate several essential regulatory functions in a wide range of biological processes and diseases, but their roles in NIHHL remain largely unknown. In order to determine the potential roles of these lncRNAs in the pathogenesis of NIHHL, we first evaluated their expression in NIHHL mice model and mapped possible regulatory functions and targets using RNA-sequencing (RNA-seq).

D-Galactose-induced oxidative stress and mitochondrial dysfunction in the cochlear basilar membrane: an in vitro aging model.

The cochlear basilar membrane (CBM) contains inner hair cells and outer hair cells that convert sound waves into electrical signals and transmit them to the central auditory system. Cochlear aging, the primary reason of age-related hearing loss, can reduce the signal transmission capacity. There is no ideal in vitro aging model of the CBM.

Age-related insult of cochlear ribbon synapses: An early-onset contributor to D-galactose-induced aging in mice.

Presbycusis results from age-related degeneration of the auditory system. D-galactose (D-gal)-induced aging is an ideal and commonly used animal model in aging research. Previous studies demonstrate that administration of D-gal can activate mitochondria-dependent apoptosis in the cochlear stria vascularis.

NADPH Oxidase 2-Mediated Insult in the Auditory Cortex of Zucker Diabetic Fatty Rats.

Clinical data has confirmed that auditory impairment may be a secondary symptom of type 2 diabetes mellitus (T2DM). However, mechanisms underlying pathologic changes that occur in the auditory system, especially in the central auditory system (CAS), remain poorly understood. In this study, Zucker diabetic fatty (ZDF) rats were used as a T2DM rat model to observe ultrastructural alterations in the auditory cortex and investigate possible mechanisms underlying CAS damage in T2DM.

The clinical characteristics of otosclerosis and benefit from stapedotomy: our experience of 48 patients (58 ears).

Stapedotomy has been proved to be one of the most efficient procedure to treat otosclerosis, various factors contribute to the diversity of the outcomes and controversial results exist from previous studies. We evaluated clinical characteristics and outcomes of stapedotomy, as well as possible predictive factors of a successful outcome. This retrospective study evaluated 58 ears from 48 patients with demographic data, plus short-term follow-up of hearing outcomes of 28 ears, and evaluated variables using univariate general linear regression analyses.

Morphological and Functional Evaluation of Ribbon Synapses at Specific Frequency Regions of the Mouse Cochlea.

Cochlear inner hair cells (IHCs) transmit acoustic signals to spiral ganglion neurons (SGNs) through ribbon synapses. Several experimental studies have indicated that hair cell synapses may be the initial targets in sensorineural hearing loss (SNHL). Such studies have proposed the concept of cochlear "synaptopathy", which refers to alterations in ribbon synapse number, structure, or function that result in abnormal synaptic transmission between IHCs and SGNs.

NADPH oxidase inhibitor apocynin decreases mitochondrial dysfunction and apoptosis in the ventral cochlear nucleus of D-galactose-induced aging model in rats.

Presbycusis has become a common sensory deficit in humans. Oxidative damage to mitochondrial DNA and mitochondrial dysfunction is strongly associated with the aging of the auditory system. A previous study established a mimetic rat model of aging using D-galactose (D-gal) and first reported that NADPH oxidase-dependent mitochondrial oxidative damage and apoptosis in the ventral cochlear nucleus (VCN) might contribute to D-gal-induced central presbycusis.

Canalostomy As a Surgical Approach to Local Drug Delivery into the Inner Ears of Adult and Neonatal Mice.

Local delivery of therapeutic drugs into the inner ear is a promising therapy for inner ear diseases. Injection through semicircular canals (canalostomy) has been shown to be a useful approach to local drug delivery into the inner ear. The goal of this article is to describe, in detail, the surgical techniques involved in canalostomy in both adult and neonatal mice.

Maximal number of pre-synaptic ribbons are formed in cochlear region corresponding to middle frequency in mice.

Objective: To investigate whether there are more quantitative pre-synaptic ribbons formed in the cochlear region corresponding to middle-frequency in cochlea of mice.

Methods: Counts of pre-synaptic ribbons were performed using immunostaining and laser confocal microscopy. Hearing thresholds and function of ribbon synapses were estimated by auditory brain response (ABR) and compound action potential (CAP).

Severe streptomycin ototoxicity in the mouse utricle leads to a flat epithelium but the peripheral neural degeneration is delayed.

The damaged vestibular sensory epithelium of mammals has a limited capacity for spontaneous hair cell regeneration, which largely depends on the transdifferentiation of surviving supporting cells. Little is known about the response of vestibular supporting cells to a severe insult. In the present study, we evaluated the impact of a severe ototoxic insult on the histology of utricular supporting cells and the changes in innervation that ensued.

The histone deacetylase inhibitor sodium butyrate protects against noise-induced hearing loss in Guinea pigs.

Noise-induced hearing loss (NIHL) severely impacts the quality of life of affected individuals. Oxidative stress resulting from noise exposure is a significant cause of NIHL. Although histone deacetylase (HDAC) inhibitors were shown to protect against NIHL, the underlying mechanism remains unclear, and it is not known how they act on noise-induced oxidative stress.

Cochleovestibular gene transfer in neonatal mice by canalostomy.

Impairments of the inner ear result in sensorineural hearing loss and vestibular dysfunction in humans. A large proportion of these disorders are congenital, and involve both auditory and vestibular systems. Therefore, genetic interventions to correct deficits must be administered during early developmental stages.