Cochlear implantation in prelingually deafened patients: Evaluation in hearing, speech ability, and quality of life. / äººå·¥è€³èœ—æ¤å ¥æœ¯æé«˜è¯­å‰è‹æ‚£è€ å¬è§‰è¨€è¯­èƒ½åŠ›åŠç”Ÿæ´»è´¨é‡.

OBJECTIVES: The main purpose of cochlear implantation for prelingual deafness is to restore the deaf children's auditory function, obtain normal speech development, learning and social ability, and improve the quality of life. Previous studies mostly focused on the improvement of simple hearing or speech ability. This study aims to evaluate the changes of hearing and speech ability and family life quality of patients after cochlear implantation, and to explore the effect of cochlear implantation on hearing and speech rehabilitation of patients. METHODS: In February 2021, using the convenient sampling method, 171 patients who have completed cochlear implantation were selected from the database of cochlear implantation follow-up center of a class III Tertiary hospital in Hunan Province. Questionnaires were used to investigate the patients' parents, which were Categories of Auditory Performance (CAP), Speech/Spatial and Qualities of Hearing Scale-Parents' Version (SSQ-P), and Children using Hearing Implants Quality of Life (CuHI-QoL). T-test and analysis of variance were used to explore the postoperative auditory and speech ability of patients at different ages in different periods (<2.5-year group, 2.5-4.5-year group and >4.5-year group), and Pearson correlation analysis was used to explore the correlation. Multiple linear regression was used to explore the relationship between the dimension of patients' quality of life and the scores of scale for evaluating auditory ability (CAP, speech perception, spatial hearing, and other hearing characteristics). RESULTS: The values of CAP and SSQ-P in the <2.5-year group were lower than those in the 2.5-4.5-year and >4.5-year groups (all P<0.05). Pearson correlation analysis showed that postoperative years and CuHI-QoL scores (parental expectations and patients' quality of life) were positively correlated with score of CAP, SSQ-P and its dimension, respectively (all P<0.05). The results of multiple linear regression analysis showed the CAP scores and speech perception were the influencing factors for the quality of life (R2=0.170, P<0.01). CONCLUSIONS: Two and a half years after operation is the rapid growth period of patients' hearing and language ability, and the growth rate becomes slow after stabilization. With the extension of postoperative years, the patients' hearing and speech ability becomes stronger, and the quality of life is better.

Anti-neutrophil cytoplasmic antibody-associated hypertrophic cranial pachymeningitis and otitis media: a review of literature.

BACKGROUND AND OBJECTIVE: It has been recognized that anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides may lead to hypertrophic pachymeningitis (HP) or intractable otitis media (OM). To our knowledge, few cases of coexistent ANCA-related HP and OM have been described previously. To increase awareness of this disease, we reviewed the literature describing patients with HP and intractable OM in a population with AAV to guide clinical decision making for otolaryngologists. METHODS:  PubMed was searched with the following terms: ANCA-associated vasculitis, otitis media, and hypertrophic pachymeningitis. Only patients with concomitant AAV, OM and HP were considered and included in this review. RESULTS: A total of 243 articles were reviewed, and of these, 6 met inclusion criteria. Headache, cranial polyneuropathy, and intractable OM with effusion or granulation were common. Serum MPO-ANCA positivity was most common in Asian patients. Almost all patients had dural mater thickening on gadolinium-enhanced magnetic resonance imaging of the brain. Corticosteroids plus an immunosuppressant was more effective and most patients had improved hearing after treatment, but approximately 50% of subjects had disease relapse. CONCLUSION: In this review, we summarized the current knowledge on the clinical features, diagnosis, treatment, and pathogenesis of this disease. We should carefully detect the potential cases of ANCA-related HP and OM in patients with intractable OM, HP, or AAV, and make the optimal treatment plan to avoid long-term neurological complications and irreversible hearing loss. Furthermore, due to an increased possibility of relapse, close follow-up, including a hearing test, ANCA titers, imaging examination, and detection of toxic and side effects of immunosuppressive therapy, are necessary.

Progressive hearing loss and degeneration of hair cell stereocilia in taperin gene knockout mice.

The TPRN gene encodes taperin, which is prominently present at the taper region of hair cell stereocilia. Mutations in TPRN have been reported to cause autosomal recessive nonsyndromic deafness 79(DFNB 79). To investigate the role of taperin in pathogenesis of hearing loss, we generated TPRN knockout mice using TALEN technique. Sanger sequencing confirmed an 11 bp deletion at nucleotide 177-187 in exon 1 of TPRN, which results in a truncated form of taperin protein. Heterozygous TPRN+/- mice showed apparently normal auditory phenotypes to their wide-type (WT) littermates. Homozygous TPRN-/- mice exhibited progressive sensorineural hearing loss as reflected by auditory brainstem response to both click and tone burst stimuli at postnatal days 15 (P15), 30 (P30), and 60 (P60). Alex Fluor-594 phalloidin labeling showed no obvious difference in hair cell numbers in the cochlea between TPRN-/- mice and WT mice under light microscope. However, scanning electronic microscopy revealed progressive degeneration of inner hair cell stereocilia, from apparently normal at postnatal days 3 (P3) to scattered absence at P15 and further to substantial loss at P30. The outer hair cell stereocilia also showed progressive degeneration, though much less severe, Collectively, we conclude that taperin plays an important role in maintenance of hair cell stereocilia. Establishment of TPRN knockout mice enables further investigation into the function of this gene.

Mutation of the ATP-gated P2X(2) receptor leads to progressive hearing loss and increased susceptibility to noise.

Age-related hearing loss and noise-induced hearing loss are major causes of human morbidity. Here we used genetics and functional studies to show that a shared cause of these disorders may be loss of function of the ATP-gated P2X(2) receptor (ligand-gated ion channel, purinergic receptor 2) that is expressed in sensory and supporting cells of the cochlea. Genomic analysis of dominantly inherited, progressive sensorineural hearing loss DFNA41 in a six-generation kindred revealed a rare heterozygous allele, P2RX2 c.178G > T (p.V60L), at chr12:133,196,029, which cosegregated with fully penetrant hearing loss in the index family, and also appeared in a second family with the same phenotype. The mutation was absent from more than 7,000 controls. P2RX2 p.V60L abolishes two hallmark features of P2X(2) receptors: ATP-evoked inward current response and ATP-stimulated macropore permeability, measured as loss of ATP-activated FM1-43 fluorescence labeling. Coexpression of mutant and WT P2X(2) receptor subunits significantly reduced ATP-activated membrane permeability. P2RX2-null mice developed severe progressive hearing loss, and their early exposure to continuous moderate noise led to high-frequency hearing loss as young adults. Similarly, among family members heterozygous for P2RX2 p.V60L, noise exposure exacerbated high-frequency hearing loss in young adulthood. Our results suggest that P2X(2) function is required for life-long normal hearing and for protection from exposure to noise.

Taurine enhances excitability of mouse cochlear neural stem cells by selectively promoting differentiation of glutamatergic neurons over GABAergic neurons.

Taurine is a sulfur-containing amino acid present in high concentrations in mammalian tissues, and has been implicated in several processes involving brain development and neurotransmission. However, the role of taurine in inner ear neural development is still largely unknown. Here we report that taurine enhanced the viability and proliferation of in vitro mouse cochlear neural stem cell culture, as well as improved neurite outgrowth. Moreover, prolonged taurine treatment also increased the neural electrical activity by escalating changes of intracellular calcium concentration, the number of spontaneous Ca(2+) oscillations in cells, and the frequencies of Ca(2+) spikes. Most importantly, we found that this escalated neural excitability by taurine was due to combined effect of increase in the population of excitatory glutamatergic neuron and decrease in inhibitory GABAergic neuron population. This is the first report on the effect of taurine to selectively promote neural stem cell differentiation by altering neuron type commitment. Our study has supported the potential of taurine as treatment against hearing loss caused by neuron degeneration, or even as an agent to improve sensitivity of hearing by increasing overall excitability of auditory nervous system.

BMP4: a Possible Key Factor in Differentiation of Auditory Neuron-Like Cells from Bone-Derived Mesenchymal Stromal Cells.

BACKGROUND: Previous studies have shown that BMP4 may play an important part in the development of auditory neurons (ANs), which are degenerated in sensorineural hearing loss. However, whether BMP4 can promote sensory fate specification from mesenchymal stromal cells (MSCs) is unknown so far. METHODS: MSCs isolated from Sprague-Dawley (SD) rats were confirmed by expression of MSC markers using flow cytometry and adipogenesis/osteogenesis using differentiation assays. MSCs treated with a complex of neurotrophic factors (BMP4 group and non-BMP4 group) were induced into auditory neuron-like cells, then the differences between the two groups were analyzed in morphological observation, cell growth curve, qRT-PCR, and immunofluorescence. RESULTS: Flow cytometric analysis showed that the isolated cells expressed typical MSC surface markers. After adipogenic and osteogenic induction, the cells were stained by oil red O and Alizarin Red. The neuronal induced cells were in the growth plateau and had special forms of neurons. In the presence of BMP4, the inner ear genes NF-M, Neurog1, GluR4, NeuroD, Calretinin, NeuN, Tau, and GATA3 were up-regulated in MSCs. CONCLUSIONS: MSCs have the capacity to differentiate into auditory neuron-like cells in vitro. As an effective inducer, BMP4 may play a key role in transdifferentiation.

Activation of the EGFR/Akt/NF-κB/cyclinD1 survival signaling pathway in human cholesteatoma epithelium.

Cholesteatoma is a benign keratinizing squamous epithelial lesion characterized by the hyper-proliferation of keratinocytes with abundant production of keratin debris in the middle ear. The epidermal growth factor receptor (EGFR)/Akt/nuclear factor-kappa B (NF-κB)/cyclinD1 signaling pathway is one of the most important pathways in regulating cell survival and proliferation. We hypothesized that the EGFR/Akt/NF-κB/cyclinD1 signaling pathway may be activated and involved in the cellular hyperplasia mechanism in acquired cholesteatoma epithelium. Immunohistochemical staining of phosphorylated EGFR (p-EGFR), phosphorylated Akt (p-Akt), activated NF-κB and cyclinD1 protein was performed in 40 cholesteatoma samples and 20 samples of normal external auditory canal (EAC) epithelium. Protein expression of p-EGFR, p-Akt, activated NF-κB and cyclinD1 in cholesteatoma epithelium was significantly increased when compared with normal EAC epithelium (p < 0.01). In cholesteatoma epithelium, a significant positive association was observed between p-EGFR and p-Akt expression and between the expressions of p-Akt and NF-κB, NF-κB and cyclinD1, respectively (p < 0.01). No significant relationships were observed between the levels of investigated proteins and the degree of bone destruction (p > 0.05). The increased protein expression of p-EGFR, p-Akt, NF-κB and cyclinD1 and their associations in cholesteatoma epithelium suggest that the EGFR/Akt/NF-κB/cyclinD1 survival signaling pathway is active and may be involved in the regulatory mechanisms of cellular hyperplasia in cholesteatoma epithelium.

The role of EGFR/PI3K/Akt/cyclinD1 signaling pathway in acquired middle ear cholesteatoma.

Cholesteatoma is a benign keratinizing and hyper proliferative squamous epithelial lesion of the temporal bone. Epidermal growth factor (EGF) is one of the most important cytokines which has been shown to play a critical role in cholesteatoma. In this investigation, we studied the effects of EGF on the proliferation of keratinocytes and EGF-mediated signaling pathways underlying the pathogenesis of cholesteatoma. We examined the expressions of phosphorylated EGF receptor (p-EGFR), phosphorylated Akt (p-Akt), cyclinD1, and proliferating cell nuclear antigen (PCNA) in 40 cholesteatoma samples and 20 samples of normal external auditory canal (EAC) epithelium by immunohistochemical method. Furthermore, in vitro studies were performed to investigate EGF-induced downstream signaling pathways in primary external auditory canal keratinocytes (EACKs). The expressions of p-EGFR, p-Akt, cyclinD1, and PCNA in cholesteatoma epithelium were significantly increased when compared with those of control subjects. We also demonstrated that EGF led to the activation of the EGFR/PI3K/Akt/cyclinD1 signaling pathway, which played a critical role in EGF-induced cell proliferation and cell cycle progression of EACKs. Both EGFR inhibitor AG1478 and PI3K inhibitor wortmannin inhibited the EGF-induced EGFR/PI3K/Akt/cyclinD1 signaling pathway concomitantly with inhibition of cell proliferation and cell cycle progression of EACKs. Taken together, our data suggest that the EGFR/PI3K/Akt/cyclinD1 signaling pathway is active in cholesteatoma and may play a crucial role in cholesteatoma epithelial hyper-proliferation. This study will facilitate the development of potential therapeutic targets for intratympanic drug therapy for cholesteatoma.

Diagnosis and treatment of nine cases with carotid artery rupture due to hypopharyngeal and cervical esophageal foreign body ingestion.

The aim of our study is to present our experience in the diagnosis and treatment of patients with carotid artery rupture (CAR) due to foreign body ingestion. A total of nine admissions with CAR due to foreign body ingestion were recorded in Second Xiangya Hospital between 1969 and 2011. The carotid artery was sutured with muscle flap coverage in six cases, ligated in three cases. We retrospectively compared different surgical procedures of the patients and their clinical outcomes. Results show that CAR was found in all of these nine cases in imaging examinations or surgery. Among these six patients treated by suture of the carotid artery, five patients had a complete recovery without any complications, one patient underwent common carotid artery (CCA) ligation after suture surgery, but finally died of massive hemorrhage due to uncontrollable infection with carotid artery erosion. Among these three patients treated only by CCA ligation, one patient had no complications, one patient had hemiplegia, and one patient died of severe cerebral edema. Hence, timely diagnosis and open surgery are important for the patients of CAR due to foreign body ingestion. Suture of the carotid artery with muscle flap coverage is a better method compared with ligation of the carotid artery in the treatment of CAR.

Hearing loss and PRPS1 mutations: Wide spectrum of phenotypes and potential therapy.

OBJECTIVE: The purpose of this review was to evaluate the current literature on phosphoribosylpyrophosphate synthetase 1 (PRPS1)-related diseases and their consequences on hearing function. DESIGN: A literature search of peer-reviewed, published journal articles was conducted in online bibliographic databases. STUDY SAMPLE: Three databases for medical research were included in this review. RESULTS: Mutations in PRPS1 are associated with a spectrum of non-syndromic to syndromic hearing loss. Hearing loss in male patients with PRPS1 mutations is bilateral, moderate to profound, and can be prelingual or postlingual, progressive or non-progressive. Audiogram shapes associated with PRPS1 deafness are usually residual and flat. Female carriers can have unilateral or bilateral hearing impairment. Gain of function mutations in PRPS1 cause a superactivity of the PRS-I protein whereas the loss-of-function mutations result in X-linked nonsyndromic sensorineural deafness type 2 (DFN2), or in syndromic deafness including Arts syndrome and X-linked Charcot-Marie-Tooth disease-5 (CMTX5). CONCLUSIONS: Lower residual activity in PRS-I leads to a more severe clinical manifestation. Clinical and molecular findings suggest that the four PRPS1 disorders discovered to date belong to the same disease spectrum. Dietary supplementation with S-adenosylmethionine (SAM) appeared to alleviate the symptoms of Arts syndrome patients, suggesting that SAM could compensate for PRS-I deficiency.

cdh23 affects congenital hearing loss through regulating purine metabolism.

Introduction: The pathogenic gene CDH23 plays a pivotal role in tip links, which is indispensable for mechanoelectrical transduction in the hair cells. However, the underlying molecular mechanism and signal regulatory networks that influence deafness is still largely unknown. Methods: In this study, a congenital deafness family, whole exome sequencing revealed a new mutation in the pathogenic gene CDH23, subsequently; the mutation has been validated using Sanger sequencing method. Then CRISPR/Cas9 technology was employed to knockout zebrafish cdh23 gene. Startle response experiment was used to compare with wide-type, the response to sound stimulation between wide-type and cdh23-/-. To further illustrate the molecular mechanisms underlying congenital deafness, comparative transcriptomic profiling and multiple bioinformatics analyses were performed. Results: The YO-PRO-1 assay result showed that in cdh23 deficient embryos, the YO-PRO-1 signal in inner ear and lateral line neuromast hair cells were completely lost. Startle response experiment showed that compared with wide-type, the response to sound stimulation decreased significantly in cdh23 mutant larvae. Comparative transcriptomic showed that the candidate genes such as atp1b2b and myof could affect hearing by regulating ATP production and purine metabolism in a synergetic way with cdh23. RT-qPCR results further confirmed the transcriptomics results. Further compensatory experiment showed that ATP treated cdh23-/- embryos can partially recover the mutant phenotype. Conclusion: In conclusion, our study may shed light on deciphering the principal mechanism and provide a potential therapeutic method for congenital hearing loss under the condition of CDH23 mutation.

Vestibular function in children with cochlear implant: Impact and evaluation.

Over the last 30 years, cochlear implant (CI) has been dedicated to improving the rehabilitation of hearing impairments. However, CI has shown potential detrimental effects on vestibular function. For children, due to atypical symptoms and difficulty in cooperating with vestibular function tests, systematic and objective assessments of vestibular function with CI have been conducted sparsely. This review focuses on the impact of vestibular function in children with CI and summarized the evaluation of vestibular function in children. In addition, some recommended strategies are summarized and proposed.

[Expression of proteinase TMPRSS3 in mouse cochlea].

OBJECTIVE: To observe the expression of proteinase transmembrane protease, serine 3 (TMPRSS3) in mouse cochlea, and to investigate the significance of TMPRSS3 in the inner ear. METHODS: The protein expression of TMPRSS3 in C57/BL mouse cochlea was identified and detected by immunohistochemistry and immunofluorescence. Different cochlear tissues, such as spiral ganglion neurons, corti organ, stria vascularis and so on, were separated to detect the gene expression of TMPRSS3 by real-time fluorescence quantitative polymerase chain reaction (qPCR). The cochlear tissues with different ages were collected and the expression of TMPRSS3 mRNA was detected by qPCR. RESULTS: TMPRSS3 was mainly expressed in the spiral ganglion neurons, and there was TMPRSS3 mRNA in the cochlea in groups with different age. The expression level of TMPRSS3 mRNA was much weaker. CONCLUSION: The distribution of TMPRSS3 was observed in many regions of the mouse cochlea, but mainly in the spiral ganglion neurons. This indicates that TMPRSS3 may be involved in the physiological functional regulation of the spiral ganglion neurons.

[Expression of TMPRSS3 in the rat cochlea following kanamycin ototoxicity].

OBJECTIVE: To establish the kanamycin-induced deafness model in SD rats, and to investigate the expression and significance of transmembrane protease, serine 3 (TMPRSS3) in the cochlea following kanamycin ototoxicity. METHODS: A total of 40 male SD rats were randomly divided into 4 groups. The experimental rats received intramuscular kanamycin sulfate for 3, 7, and 14 consecutive days, and the control group were treated with normal saline for 14 days. Auditory brainstem responses (ABR) were obtained before and after the kanamycin administration. The expression of TMPRSS3 in the cochlea was identified and detected by immunohistochemistry and Western blot. RESULTS: Kanamycin-induced deafness model in the SD rats was successfully established. ABR thresholds were increased and the expression of TMPRSS3 in the cochlea was reduced after the kanamycin injection (P<0.01). CONCLUSION: TMPRSS3 may play an important role in normal cochlea function and involve in the process of aminoglycoside antibiotics induced deafness.

[Aberrant expression pattern of a novel mutation in connexin 26 gene resulting in autosomal recessive deafness].

OBJECTIVE: To report a novel deafness-causing mutation c.465T>A, p.Y155X in connexin 26 (CX26) (also called gap junction protein beta-2, GJB2), and perform functional analysis of the mutated protein p.Y155X in Hela cells to explore the underlying mechanism on deafness. METHODS: Mutations in CX26 gene of the proband in an autosomal recessive inherited deafness family were tested by direct DNA sequencing method. Mutant p.Y155X, which was found in the deafness family, and wild type CX26 (wtCX26), were directionally subcloned into the pEGFP-N1 plasmid to construct the recombinant fusion protein expression vector of CX26 p.Y155X-EGFP and wtCX26-EGFP, followed by transfecting into HeLa cells. The expression of the mutated and wild type proteins was analyzed using Western blot analysis. The intracellular localization of proteins and the formation of gap junction-like plaques at plasma membrane were observed under confocal microscope. Gap junction coupling was tested by calcein-AM dye transfer experiment. RESULTS: A novel nonsense mutation c.465T>A, p.Y155X in the CX26 gene was found in the autosomal recessive deafness family. The molecular weight of protein p.Y155X was smaller than that of wtCX26 in transiently expressed HeLa cells. The mutated protein failed to reach the cell surface to form gap junction plaques, and displayed cytoplasmic accumulation. Also, no calcein-AM dye was transferred from the donor cells to the recipient cells when both were transfected with CX26 p.Y155X. The wtCX26 protein localized at the cell membrane to form gap junction plaques with permeability to fluorescent dye calcein AM. CONCLUSION: CX26 p.Y155X could not be targeted to the plasma membrane and there was no formation of gap junction channels between the adjacent cells. The mutation c.465T>A, p.Y155X in CX26 gene was responsible for the autosomal recessive hearing impairment in this family.

[An analysis of surgical management of difficulties during cochlear implant with inner ear anomalies].

Objective:The purpose of this study is to review the difficulties that can occur during cochlear implant surgery in patients with inner ear abnormalities and the management. Method:A retrospective analysis was made on 186 cases of cochlear implant with inner ear malformation, the types of inner ear malformations included 6 cases（3.23%） of isolated semicircular dysplasia, 137 cases（73.66%） of isolated large vestibular aqueducts, 26 cases（13.98%） of Mondini malformations, 6 cases（3.23%） of incomplete septal type Ⅲ, 3 cases（1.61%） of internal auditory stenosis, 7 cases（3.76%） of cochlear dysplasia and 1 case（0.54%） of incomplete septal typeⅠ. Two hundred patients with normal inner ear structures were randomly selected as the control group. The data collected included the types of inner ear abnormalities, intraoperative manifestations, clinical management strategies, and postoperative speech rehabilitation, and the literature was reviewed. Result:148 patients（77.49%） with inner ear malformation underwent successful surgery, electrode insertion was incomplete in 6 patients（3.14%）, and cerebrospinal fluid blowout occurred in 29 patients（15.18%）, it was difficult to locate the window because of the abnormal structure of the window in 8 cases（4.19%）. In 191 patients, the facial recess approach was adopted intraoperatively, and 17.8% of the patients had significant structural abnormalities of the facial nerve, significantly more than the group with normal inner ear structure. Only 1 patient showed delayed facial nerve paralysis 1 week after surgery, and recovered well after treatment. 6.81% of the patients adopted the expanded round window approach, which was significantly lower than that of the group with normal inner ear structure（28%）. There was no significant difference between patients with inner ear malformation and patients with extremely severe deafness with normal inner ear structure who received cochlear implant in speech rehabilitation. Conclusion:Cochlear implant is safe, feasible and effective for patients with inner ear malformation. For patients with inner ear malformation, special attention should be paid to the preoperative imaging reading to predict the possible risks during the operation. The safest surgical plan, including the type of electrode and the manner in which the window is opened, must be prepared before the operation, and the operation must be performed or directed by an experienced surgeon who can adjust the optimal surgical plan according to what is seen during the operation.

Congenital Middle Ear Malformation with Common Deafness Gene Mutation Analysis: A Review of 813 Profound Sensorineural Hearing Loss Child Patients.

Deafness gene variants play a key role in inner ear malformations. However, the relationship between congenital middle ear malformations and common deafness genes (GJB2, SLC26A4, and mtDNA) in profound sensorineural hearing loss (SNHL) child patients remains poorly investigated. Here we showed that there was no statistical significance in the total mutation frequency of the three common deafness genes in the middle ear malformation group (21.2%, 41/193) in comparison with the normal middle ear and inner ear group (21.0%, 116/553) (χ2 = 0.0061, p = 0.940). Moreover, the mutation ratio of GJB2 and SLC26A4 in the middle ear malformation group (18.7%, 36/193; 2.6%, 5/193) was not significantly different from that in the normal middle ear and inner ear group (17.7%, 98/553; 2.4%, 13/553) (χ2 = 0.084, p = 0.772; χ2 = 0.0000, p = 1.000). The mutation ratio of GJB2 235delC and GJB2 79G>A in the middle ear malformation group (8.8%, 17/193; 8.8%, 17/193) was almost the same to that in the normal middle ear and inner ear group (8.6%, 48/553; 6.7%, 37/553) (χ2 = 0.0030, p = 0.957; χ2 = 0.9556, p = 0.328). The high jugular bulb subgroup analysis also showed the same results. Our findings suggested that GJB2, SLC26A4, and mtDNA mutations might not be related to the middle ear malformations in profound SNHL child patients. Anat Rec, 303:594-599, 2020. © 2019 American Association for Anatomy.

Efficient introduction of an isogenic homozygous mutation to induced pluripotent stem cells from a hereditary hearing loss family using CRISPR/Cas9 and single-stranded donor oligonucleotides.

BACKGROUND: Heterozygous purinergic receptor p2x gene ( P2RX2) c.178G>T (p.V60L) mutations can lead to progressive hearing loss (HL) and increased susceptibility to noise. However, the underlying mechanisms remain unclear. A combination of human induced pluripotent stem cell (hiPSC) technology with clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein (Cas)9-mediated gene editing may provide a promising tool to study gene function and treat hereditary deafness in humans. METHODS: hiPSC technology and CRISPR/Cas9-mediated gene editing were used to generate heterozygous and homozygous P2RX2 c.178G>T (p.V60L) cell models. RESULTS: We generated non-integrative hiPSCs from urine samples derived from three members of a large Chinese family carrying heterozygous P2RX2 c.178G>T mutations (designated P2RX2+/-) as a model to study P2RX2-mediated hereditary HL. Furthermore, we used CRISPR/Cas9 and single-stranded donor oligonucleotides to genetically establish homozygous P2RX2 c.178G>T hiPSCs (designated P2RX2-/-) from heterozygous patient-specific hiPSCs as a control to further study the pathological gene function. CONCLUSIONS: Heterozygous and homozygous P2RX2-mutated hiPSC lines are good models to investigate the pathological mechanisms of P2RX2 mutations in HL pathogenesis. Our findings confirmed our hypothesis that it is feasible and convenient to introduce precise point mutations into genomic loci of interest to generate gene-mutated hiPSC models.

Role of Hsp90/Akt pathway in the pathogenesis of gentamicin-induced hearing loss.

Studies have suggested that gentamicin may induce hair cell apoptosis through the Hsp90/Akt signaling pathway. Nevertheless, the exact mechanisms remain unclear. The following study investigated Hsp90 expression in gentamicin-treated cochleae (in vitro and in vivo) and explored whether the Hsp90/Akt signaling pathway has a role in gentamicin ototoxicity. For in vitro experiments, organotypic cultures from post-natal organ of Corti, collected from post-natal day 2 or 3 (p2-3) CBA/J explants were treated with 0.2 mM gentamicin for 24 h; for the in vivo experiments, 6-week-old male CBA/J mice were injected with gentamicin (150 mg/kg) to induce hearing loss. P-Akt and AKT proteins expression and the levels of Hsp90-Akt complex were examined using immunochemistry and western blot. Our data suggested that Hsp90 expression decreased in the hair ear cells after treatment. In addition, the pAkt and Hsp90/AKT levels significantly decreased in treated mice compared to the control group. To conclude, these results support the idea that the Hsp90/Akt signaling pathway may have an important role in the ototoxic effects of gentamicin.

Subunits of voltage-gated calcium channels in murine spiral ganglion cells.

CONCLUSION: The results show that alpha1D, alpha1E, alpha2/delta, beta1, and beta3 subunits are expressed in spiral ganglion cells (SGCs), and the coexpression of alpha1D and alpha1E suggests the presence of L-type and R-type calcium channels in mammalian SGCs. OBJECTIVE: To investigate the types of subunits of voltage-gated calcium channels in SGCs of the mouse. MATERIALS AND METHODS: SGCs were isolated from cochleae of neonatal mice and cultured for 24 h. Total RNA was extracted from cultured cells. After reverse transcription, the resulting cDNA was amplified by PCR with primers targeted to nucleotide sequences corresponding to seven different calcium channel subunits. The types of calcium channel subunits were identified by PCR analysis and nucleotide sequencing. RESULTS: RT-PCR showed the strong and consistent amplification of alpha1D, alpha1E, alpha2/delta, beta1, and beta3 subunits from the mRNA of SGCs, and nucleotide sequencing confirmed the identity of mouse cochlear subunit cDNAs.