This study aimed to investigate the efficacy of gene therapy for treating autoimmune sensorineural hearing loss (ASHL) via local administration of a recombinant adenovirus vector containing the Fas ligand or interleukin IL-10 gene. Guinea pigs were divided into four groups, with different microinjections in the scala tympani. Group A were injected with FasL-EGFP, B with IL-10-EGFP, C with EGFP, and D with artificial perilymph. Seven days later, auditory brain-stem response (ABR) was tested, and the temporal bone was stained and observed by light microscopy. The spiral ligament and basement membrane were observed using transmission electron microscopy. FasL and IL-10 expression were examined using immunofluorescence histochemistry. Immunohistochemical analysis showed that the recombinant adenovirus vector in Groups A, B, and C can transfect the stria vascularis, the spiral ligament, the organ of Corti, the spiral ganglion, the region surrounding the small blood vessel in the modiolus, and the cochlear bone wall. Compared with those in Groups C and D, the ABR wave III mean thresholds were significantly lower and the inner ear immunoinflammatory responses in Groups A and B were significantly alleviated. Inhibition of immunoinflammatory response alleviated immunoinflammatory injury and auditory dysfunction. This technique shows potential as a novel therapy for ASHL.

This study aimed to investigate the localization pattern of glucose transporters (Gluts) in mouse cochlea. Genome-wide gene expression analysis using CodeLink™ bioarrays indicated that Glut1 and Glut10 were highly expressed (~10-fold) in mouse cochlea compared with the other members of glucose transporters (Glut2-6, Glut8, and Glut9). Semiquantitative RT-PCR and western blotting confirmed that Glut10 expression in mouse cochlea was high throughout the embryogenesis and postnatal development. Immunofluorescent staining showed that Glut10 protein was localized in the cuticular plate of the outer and inner cochlear hair cells and in the ampullary crest of the vestibular system. Based on these results, it was supposed that Glut10 may contribute to glucose transport from the endolymph to the hair cells across the cuticular plate.

Specific clinical conditions could compromise cochlear implantation outcomes and drastically reduce the chance of an acceptable development of perceptual and linguistic capabilities. These conditions should certainly include the presence of inner ear malformations or brain abnormalities. The aims of this work were to study the diagnostic value of high resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in children with sensorineural hearing loss who were candidates for cochlear implants and to analyse the anatomic abnormalities of the ear and brain in patients who underwent cochlear implantation. We also analysed the effects of ear malformations and brain anomalies on the CI outcomes, speculating on their potential role in the management of language developmental disorders.

Pendrin is encoded by SLC26A4, which is expressed in the apical membrane of inner ear epithelial cells and drives chloride reabsorption in the apical septum. In the inner ear, pendrin dysfunction and hypofunctional mutations lead to vestibular aqueduct (EVA) enlargement and sensory neural hearing loss. Mutations in SLC26A4 are a common reason of deafness. However, the underlying mechanisms of SLC26A4 mutants in hearing loss remain unknown.

In this study, we evaluated the efficacy of acupuncture in the treatment of obesity by a computational framework integrating randomized controlled trials published in China and abroad. Specifically, clinical trial documents published on CNKI, VIP, Wanfang, PubMed, Embase, and the Cochrane Library from 2007-2017 were downloaded and analyzed using Stata 15.1 system. As a result, a total of 13 articles were imported and 1052 patients were included. The analyses showed that the overall effect of an acupuncture group and a control group was not significant with P > 0.01. However, the curative effect of the acupuncture group was better than that of the diet and exercise instruction group with P < 0.01; the curative effect of the acupuncture group was better than that of the oral Chinese and western medicine group with P < 0.01. In conclusion, acupuncture as a complementary alternative therapy is recommended for the treatment of obesity.

Gene therapy for sensorineural hearing loss has recently been used to insert genes encoding functional proteins to preserve, protect, or even regenerate hair cells in the inner ear. Our previous study demonstrated a microbubble- (MB-)facilitated ultrasound (US) technique for delivering therapeutic medication to the inner ear. The present study investigated whether MB-US techniques help to enhance the efficiency of gene transfection by means of cationic liposomes on HEI-OC1 auditory cells and whether MBs of different sizes affect such efficiency. Our results demonstrated that the size of MBs was proportional to the concentration of albumin or dextrose. At a constant US power density, using 0.66, 1.32, and 2.83 μm albumin-shelled MBs increased the transfection rate as compared to the control by 30.6%, 54.1%, and 84.7%, respectively; likewise, using 1.39, 2.12, and 3.47 μm albumin-dextrose-shelled MBs increased the transfection rates by 15.9%, 34.3%, and 82.7%, respectively. The results indicate that MB-US is an effective technique to facilitate gene transfer on auditory cells in vitro. Such size-dependent MB oscillation behavior in the presence of US plays a role in enhancing gene transfer, and by manipulating the concentration of albumin or dextrose, MBs of different sizes can be produced.

Bone marrow mesenchymal stem cells (BMSCs) expressing recombinant IL-4 have the potential to remediate inflammatory diseases. We thus investigated whether BMSCs expressing exogenous IL-4 could alleviate autoimmune sensorineural hearing loss. BMSCs isolated from guinea pigs were transfected with recombinant lentivirus expressing IL-4. A total of 33 animals were divided into three groups. Group A received scala tympani injection of IL-4-expressing BMSCs, and Group B received control vector-expressing BMSCs, and Group C received phosphate-buffered saline. The distribution of implanted BMSCs in the inner ears was assessed by immunohistochemistry and fluorescence microscopy. Auditory brain-stem response (ABR) was monitored to evaluate the auditory changes. Following BMSCs transplantation, the threshold levels of ABR wave III decreased in Groups A and B and significant differences were observed between these two groups (P < 0.05). Transplanted BMSCs distributed in the scala tympani and scala vestibuli. In some ears with hearing loss, there was a decrease in the number of spiral ganglion cells and varying degrees of endolymphatic hydrops or floccule. Following transplantation, the lentivirus-infected BMSCs migrated to the inner ear and produced IL-4. Our results demonstrate that, upon transplantation, BMSCs and BMSCs expressing recombinant IL-4 have the ability to remediate the inflammatory injury in autoimmune inner ear diseases.

In order to achieve a minimal trauma to the inner ear structures during array insertion, it would be suitable to control insertion forces. The aim of this work was to compare the insertion forces of an array insertion into anatomical specimens with three different insertion techniques: with forceps, with a commercial tool, and with a motorized tool.

Impairment of cochlear blood flow has been discussed as factor in the pathophysiology of various inner ear disorders. However, the microscopic study of cochlear microcirculation is limited due to small scale and anatomical constraints. Here, two-photon fluorescence microscopy is applied to visualize cochlear microvessels. Guinea pigs were injected with Fluorescein isothiocyanate- or Texas red-dextrane as plasma marker. Intravital microscopy was performed in four animals and explanted cochleae from four animals were studied. The vascular architecture of the cochlea was visualized up to a depth of 90.0±22.7 μm. Imaging yielded a mean contrast-to-noise ratio (CNR) of 3.3±1.7. Mean diameter in vivo was 16.5±6.0 μm for arterioles and 8.0±2.4 μm for capillaries. In explanted cochleae, the diameter of radiating arterioles and capillaries was measured with 12.2±1.6 μm and 6.6±1.0 μm, respectively. The difference between capillaries and arterioles was statistically significant in both experimental setups (P<0.001 and P=0.022, two-way ANOVA). Measured vessel diameters in vivo and ex vivo were in agreement with published data. We conclude that two-photon fluorescence microscopy allows the investigation of cochlear microvessels and is potentially a valuable tool for inner ear research.

As a homing factor of stem cell, stromal derived factor-1 (SDF-1) is important for the regenerative research in ototoxicity. Mice models with aminoglycoside ototoxicity have been widely used to study the regeneration capacity of MSCs in repair of cochlear injury. We developed a mouse model with maximal increase in SDF-1 levels in the inner ear, according to the "one-shot" doses of kanamycin and furosemide.

To date, about 165 genetic loci or genes have been identified which are associated with nonsyndromal hearing impairment. In about half the cases, genetic defects in the GJB2 gene (connexin 26) are the most common cause of inner-ear deafness. The genes GJB2 and GJB6 are localized on chromosome 13q11-12 in tandem orientation. Connexins belong to the group of "gap junction" proteins, which form connexons, each consisting of six connexin molecules. These are responsible for the exchange of ions and smaller molecules between neighboring cells. Mutational analysis in genes GJB2 and GJB6 was brought by direct sequencing of the coding exons including the intron transitions. Here we show in the participating extended family a homozygous mutation c.506G>A, (TGC>TAC) p.Cys169Tyr, in the GJB2 gene, which could be proven for the first time and led to nonsyndromal severe hearing impairment in the afflicted patients. The mutation is located in the EC1/EC2 interaction complex of the gap junction connexon 26 complex and interrupts the K(+) circulation and therefore the ion homeostasis in the inner ear. The homozygous mutation p.Cys169Tyr identified here provides a novel insight into the structure-function relationship of the gap junction complex connexin/connexon 26.

The inner ear is an essential part of a well-developed and well-coordinated hearing system. However, hearing loss can make communication and interaction more difficult. Inherited hearing loss (HL) can occur from pathogenic genetic variants that negatively alter the intricate inner ear sensory mechanism. Recessively inherited forms of HL are highly heterogeneous and account for a majority of prelingual deafness. The current study is designed to investigate genetic causes of HL in three consanguineous Pakistani families. After IRB approval, the clinical history and pure tone audiometric data was obtained for the clinical diagnosis of HL segregating in these three Pakistani families. We performed whole exome sequencing (WES) followed by Sanger sequencing in order to identify and validate the HL-associated pathogenic variants, respectively. The 3-D molecular modeling and the Ramachandran analysis of the identified missense variants were compiled to evaluate the impact of the variants on the encoded proteins. Clinical evaluation revealed prelingual severe to profound sensorineural HL segregating among the affected individuals in all three families. Genetic analysis revealed segregation of several novel variants associated with HL, including a canonical splice-site variant (c.55-2A>G) of PTPRQ in family GCFHL-01, a missense variant [c.1079G>A; p.(Arg360Gln)] of SERPINB6 in family LUHL-01, and an insertion variant (c.10208-10211insCCACCAGGCCCGTGCCTC) within MYO15A in family LUHL-011. All the identified variants had very low frequencies in the control databases. The molecular modeling of p.Arg360Gln missense variant also predicted impaired folding of SERPINB6 protein. This study reports the identification of novel disease-causing variants in three known deafness genes and further highlights the genetic heterogeneity of HL in Pakistani population.

A major component of minimally invasive cochlear implantation is atraumatic scala tympani (ST) placement of the electrode array. This work reports on a semiautomatic planning paradigm that uses anatomical landmarks and cochlear surface models for cochleostomy target and insertion trajectory computation. The method was validated in a human whole head cadaver model (n = 10 ears). Cochleostomy targets were generated from an automated script and used for consecutive planning of a direct cochlear access (DCA) drill trajectory from the mastoid surface to the inner ear. An image-guided robotic system was used to perform both, DCA and cochleostomy drilling. Nine of 10 implanted specimens showed complete ST placement. One case of scala vestibuli insertion occurred due to a registration/drilling error of 0.79 mm. The presented approach indicates that a safe cochleostomy target and insertion trajectory can be planned using conventional clinical imaging modalities, which lack sufficient resolution to identify the basilar membrane.

Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp.) are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation.

Background. Even if various pathophysiological events have been proposed as explanations, the putative cause of sudden hearing loss remains unclear. Objectives. To investigate and to reveal associations (if any) between the main iron-related gene variants and idiopathic sudden sensorineural hearing loss. Study Design. Case-control study. Materials and Methods. A total of 200 sudden sensorineural hearing loss patients (median age 63.65 years; range 10-92) were compared with 400 healthy control subjects. The following genetic variants were investigated: the polymorphism c.-8CG in the promoter of the ferroportin gene (FPN1; SLC40A1), the two isoforms C1 and C2 (p.P570S) of the transferrin protein (TF), the amino acidic substitutions p.H63D and p.C282Y in the hereditary hemochromatosis protein (HFE), and the polymorphism c.-582AG in the promoter of the HEPC gene, which encodes the protein hepcidin (HAMP). Results. The homozygous genotype c.-8GG of the SLC40A1 gene revealed an OR for ISSNHL risk of 4.27 (CI 95%, 2.65-6.89; P = 0.001), being overrepresented among cases. Conclusions. Our study indicates that the homozygous genotype FPN1 -8GG was significantly associated with increased risk of developing sudden hearing loss. These findings suggest new research should be conducted in the field of iron homeostasis in the inner ear.

Noise-induced hearing loss (NIHL) is a global health problem affecting over 5% of the population worldwide. We have shown previously that acute noise-induced cochlear injury can be ameliorated by administration of drugs acting on adenosine receptors in the inner ear, and a selective A1 adenosine receptor agonist adenosine amine congener (ADAC) has emerged as a potentially effective treatment for cochlear injury and resulting hearing loss. This study investigated pharmacokinetic properties of ADAC in rat perilymph after systemic (intravenous) administration using a newly developed liquid chromatography-tandem mass spectrometry detection method. The method was developed and validated in accordance with the USA FDA guidelines including accuracy, precision, specificity, and linearity. Perilymph was sampled from the apical turn of the cochlea to prevent contamination with the cerebrospinal fluid. ADAC was detected in cochlear perilymph within two minutes following intravenous administration and remained in perilymph above its minimal effective concentration for at least two hours. The pharmacokinetic pattern of ADAC was significantly altered by exposure to noise, suggesting transient changes in permeability of the blood-labyrinth barrier and/or cochlear blood flow. This study supports ADAC development as a potential clinical otological treatment for acute sensorineural hearing loss caused by exposure to traumatic noise.