scholarly journals Long-Term Release of Dexamethasone With a Polycaprolactone-Coated Electrode Alleviates Fibrosis in Cochlear Implantation

2021 ◽  
Vol 9 ◽  
Author(s):  
Dongxiu Chen ◽  
Yanjing Luo ◽  
Jing Pan ◽  
Anning Chen ◽  
Dong Ma ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cochlear Implantation ◽  
Treatment Effectiveness ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Related Factors ◽  
Electrode Coating ◽  
Promising Application ◽  
Major Treatment ◽  
The Stability

Cochlear implantation (CI) is the major treatment for severe sensorineural hearing loss. However, the fibrotic tissue forming around the electrodes reduces the treatment effectiveness of CI. Dexamethasone (DEX) is usually applied routinely in perioperative treatment of cochlear implantation (CI), but its diffusion in the inner ear after systemic administration is limited. In the present study, an electrode coated with polycaprolactone (PCL) loaded with dexamethasone was developed with a simple preparation process to maintain the stability of the electrode itself. The DEX-loaded PCL coating has good biocompatibility and does not change the smoothness, flexibility, or compliance of the implant electrode. Stable and effective DEX concentrations were maintained for more than 9 months. Compared with the pristine electrode, decreasing intracochlear fibrosis, protection of hair cells and spiral ganglion cells, and better residual hearing were observed 5 weeks after PCL-DEX electrode implantation. The PCL-DEX electrode has great potential in preventing hearing loss and fibrosis by regulating macrophages and inhibiting the expression of the fibrosis-related factors IL-1β, TNF-α, IL-4, and TGF-β1. In conclusion, the PCL-DEX electrode coating shows promising application in CI surgery.

scholarly journals Intrinsically Self-renewing Neuroprogenitors From the A/J Mouse Spiral Ganglion as Virtually Unlimited Source of Mature Auditory Neurons

2020 ◽  
Vol 14 ◽  
Author(s):  
Francis Rousset ◽  
Vivianne B. C. Kokje ◽  
Rebecca Sipione ◽  
Dominik Schmidbauer ◽  
German Nacher-Soler ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Progenitor Cells ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Specific Cell ◽  
Auditory Neurons ◽  
Self Renewal ◽  
Starting Point ◽  
Ganglion Neurons

Nearly 460 million individuals are affected by sensorineural hearing loss (SNHL), one of the most common human sensory disorders. In mammals, hearing loss is permanent due to the lack of efficient regenerative capacity of the sensory epithelia and spiral ganglion neurons (SGN). Sphere-forming progenitor cells can be isolated from the mammalian inner ear and give rise to inner ear specific cell types in vitro. However, the self-renewing capacities of auditory progenitor cells from the sensory and neuronal compartment are limited to few passages, even after adding powerful growth factor cocktails. Here, we provide phenotypical and functional characterization of a new pool of auditory progenitors as sustainable source for sphere-derived auditory neurons. The so-called phoenix auditory neuroprogenitors, isolated from the A/J mouse spiral ganglion, exhibit robust intrinsic self-renewal properties beyond 40 passages. At any passage or freezing–thawing cycle, phoenix spheres can be efficiently differentiated into mature spiral ganglion cells by withdrawing growth factors. The differentiated cells express both neuronal and glial cell phenotypic markers and exhibit similar functional properties as mouse spiral ganglion primary explants and human sphere-derived spiral ganglion cells. In contrast to other rodent models aiming at sustained production of auditory neurons, no genetic transformation of the progenitors is needed. Phoenix spheres therefore represent an interesting starting point to further investigate self-renewal in the mammalian inner ear, which is still far from any clinical application. In the meantime, phoenix spheres already offer an unlimited source of mammalian auditory neurons for high-throughput screens while substantially reducing the numbers of animals needed.

Diameter of the Cochlear Nerve in Deaf Humans: Implications for Cochlear Implantation

1992 ◽  
Vol 101 (12) ◽  
pp. 988-993 ◽  
Author(s):  
Joseph B. Nadol ◽  
Wen-Zhuang Xu
Keyword(s):  
Ganglion Cell ◽  
Cell Count ◽  
Cochlear Implantation ◽  
Ganglion Cells ◽  
Cranial Nerves ◽  
Spiral Ganglion ◽  
Normal Hearing ◽  
Maximum Diameter ◽  
Eighth Nerve ◽  
Spiral Ganglion Cell

Although the parameters that are most important for postoperative speech perception in cochlear implantation have not been identified, it is assumed that the numbers of remaining cochlear neurons and spiral ganglion cells in the implanted deaf ears are critical. In this study, we evaluated the correlation of the maximum diameter of the cochlear and vestibular nerve trunks with the number of spiral ganglion cells in horizontal sections of the temporal bone of 42 patients who were profoundly deaf during life, and in 5 patients with normal hearing. The maximum diameters of the cochlear, vestibular, and eighth cranial nerves were significantly smaller in the deaf population as compared to normal-hearing controls. In addition, the counts of the remaining spiral ganglion cells were significantly correlated with the maximum diameter of the cochlear (p = .0006), vestibular (p = .001), and eighth cranial nerves (p = .0003). The regression equation estimated that 25% of the variance of the spiral ganglion cell count was predicted by the maximum diameter of the eighth nerve. Although the results of this study suggest that preoperative radiographic imaging of the diameter of the eighth nerve may be helpful in predicting the residual spiral ganglion cell count, the wide variability of diameters of the eighth nerve in hearing and deaf subjects militates against this theoretic usefulness.

Survival of Spiral Ganglion Cells in Profound Sensorineural Hearing Loss: Implications for Cochlear Implantation

1989 ◽  
Vol 98 (6) ◽  
pp. 411-416 ◽  
Author(s):  
Joseph B. Nadol ◽  
Yi-Shyang Young ◽  
Robert J. Glynn
Keyword(s):  
Hearing Loss ◽  
Ganglion Cell ◽  
Cell Count ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Bivariate Analysis ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
Profound Deafness ◽  
Temporal Bones

Ninety-three temporal bones from 66 patients who were profoundly deaf during life were reconstructed by analysis of serial light microscopic sections. The correlations of total and segmental spiral ganglion cell counts with age, duration of hearing loss and profound deafness, and cause of hearing loss were evaluated. Bivariate analysis demonstrated that total spiral ganglion cell count tended to be lower in older than in younger deaf individuals and lower with longer duration of hearing loss and total deafness. However, multiple regression analysis demonstrated that the cause of hearing loss was the single most significant determinant of total spiral ganglion cell count. Patients with deafness due to aminoglycoside toxicity or sudden idiopathic deafness had the highest residual spiral ganglion cell count and patients with deafness due to presumptive postnatal viral labyrinthitis, bacterial labyrinthitis, and congenital or genetic causes had the lowest numbers of residual spiral ganglion cells.

scholarly journals Cochlear Implantation: An Overview

2018 ◽  
Vol 80 (02) ◽  
pp. 169-177 ◽  
Author(s):  
Nicholas Deep ◽  
Eric Dowling ◽  
Daniel Jethanamest ◽  
Matthew Carlson
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Auditory Brainstem ◽  
Electrical Signal ◽  
Sensorineural Hearing ◽  
Acoustic Energy ◽  
Lateral Skull Base ◽  
Single Sided Deafness

AbstractA cochlear implant (CI) is a surgically implanted device for the treatment of severe to profound sensorineural hearing loss in children and adults. It works by transducing acoustic energy into an electrical signal, which is used to stimulate surviving spiral ganglion cells of the auditory nerve. The past 2 decades have witnessed an exponential rise in the number of CI surgeries performed. Continual developments in programming strategies, device design, and minimally traumatic surgical technique have demonstrated the safety and efficacy of CI surgery. As a result, candidacy guidelines have expanded to include both pre and postlingually deaf children as young as 1 year of age, and those with greater degrees of residual hearing. A growing proportion of patients are undergoing CI for off-label or nontraditional indications including single-sided deafness, retrocochlear hearing loss, asymmetrical sensorineural hearing loss (SNHL) in adults and children with at least 1 ear that is better than performance cut-off for age, and children less than 12 months of age. Herein, we review CI design, clinical evaluation, indications, operative technique, and outcomes. We also discuss the expanding indications for CI surgery as it relates to lateral skull base pathology, comparing CI to auditory brainstem implants, and address the concerns with obtaining magnetic resonance imaging (MRI) in CI recipients.

scholarly journals PIN1 Protects Hair Cells and Auditory HEI-OC1 Cells against Senescence by Inhibiting the PI3K/Akt/mTOR Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yanzhuo Zhang ◽  
Zhe Lv ◽  
Yudong Liu ◽  
Huan Cao ◽  
Jianwang Yang ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Cell Senescence ◽  
Prolyl Isomerase ◽  
Age Related ◽  
Pin1 Protein

A growing amount of evidence has confirmed the crucial role of the prolyl isomerase PIN1 in aging and age-related diseases. However, the mechanism of PIN1 in age-related hearing loss (ARHL) remains unclear. Pathologically, ARHL is primarily due to the loss and dysfunction of hair cells (HCs) and spiral ganglion cells (SGCs) in the cochlea. Therefore, in this study, we aimed to investigate the role of PIN1 in protecting hair cells and auditory HEI-OC1 cells from senescence. Enzyme-linked immunosorbent assays, immunohistochemistry, and immunofluorescence were used to detect the PIN1 protein level in the serum of ARHL patients and C57BL/6 mice in different groups, and in the SGCs and HCs of young and aged C57BL/6 mice. In addition, a model of HEI-OC1 cell senescence induced by H2O2 was used. Adult C57BL/6 mice were treated with juglone, or juglone and NAC, for 4 weeks. Interestingly, we found that the PIN1 protein expression decreased in the serum of patients with ARHL, in senescent HEI-OC1 cells, and in the cochlea of aged mice. Moreover, under H2O2 and juglone treatment, a large amount of ROS was produced, and phosphorylation of p53 was induced. Importantly, PIN1 expression was significantly increased by treatment with the p53 inhibitor pifithrin-α. Overexpression of PIN1 reversed the increased level of p-p53 and rescued HEI-OC1 cells from senescence. Furthermore, PIN1 mediated cellular senescence by the PI3K/Akt/mTOR signaling pathway. In vivo data from C57BL/6 mice showed that treatment with juglone led to hearing loss. Taken together, these findings demonstrated that PIN1 may act as a vital modulator in hair cell and HEI-OC1 cell senescence.

Scala Vestibuli Partition with Deafness and Renal Disease

1973 ◽  
Vol 82 (6) ◽  
pp. 871-875 ◽  
Author(s):  
Ruth Gussen
Keyword(s):  
Hearing Loss ◽  
Renal Disease ◽  
Immunosuppressive Therapy ◽  
Ganglion Cells ◽  
Chronic Renal Disease ◽  
Spiral Ganglion ◽  
Spiral Ligament ◽  
Cochlear Hearing Loss ◽  
The Brain ◽  
Scala Vestibuli

Spiral ligament projections, partitioning the beginning of the scala vestibuli, bilaterally, were demonstrated in a patient with chronic renal disease, who had a bilateral midfrequency cochlear hearing loss. There were also spongy spiral ligament changes, strial atrophy and decreased spiral ganglion cells in the basal and middle cochlear turns. The patient was maintained on immunosuppressive therapy for four years after receiving a renal transplant. He died of a primary malignant lymphoma of the brain and cryptococcal meningitis, both probably related to immunosuppressive therapy.

scholarly journals A maradványhallás megőrzésének lehetőségei cochlearis implantáció során Nucleus CI532 Slim Modiolar elektródasorral

2018 ◽  
Vol 159 (41) ◽  
pp. 1680-1688 ◽  
Author(s):  
Roland Nagy ◽  
János András Jarabin ◽  
Balázs Dimák ◽  
Ádám Perényi ◽  
Ferenc Tóth ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Minimally Invasive ◽  
Cochlear Implantation ◽  
Basilar Membrane ◽  
Round Window ◽  
Spiral Ganglion ◽  
Hearing Threshold ◽  
Electrode Array ◽  
Hearing Preservation ◽  
Residual Hearing

Abstract: During the rehabilitation of hearing-impaired patients, the preservation of residual acoustic hearing following cochlear implantation by minimizing the implantation trauma allows for improved hearing performance. To achieve this, minimally invasive, soft surgery methods and thinner, atraumatic electrodes were required. In our present study, we reported a case where Cochlear® Nucleus CI532 Slim Modiolar electrode was implanted in a patient with residual hearing. Our aim was to study the possible preservation of postoperative acoustic residual hearing by audiological monitoring. Since childhood, due to her congenital hearing loss, she has been wearing a conventional, airborne hearing correction device on both ears. Six months before cochlear implantation, we measured the progression on both sides of the hearing loss, so we decided to perform cochlear implantation. The patient had residual hearing on both ears prior to surgery thus the Cochlear® Nucleus CI532 Slim Modiolar Implant was used. The minimally invasive surgery was performed on the patient’s right ear through the round window approach. Compared to the preoperative hearing threshold (average 85 dBHL) in the 4th postoperative week, an initial hearing threshold progression of 20–25 dBHL was observed between 0.25 and 1.0 kHz, while of 5–10 dBHL between 2.0–4.0 kHz. Hearing threshold measured in the 6th month showed a slight progression in the range above 1 kHz, but improved by the 12th month, to the results achieved at the 4th week. The effects of cochlear implantation on residual hearing have been studied in numerous studies, in which several key surgical and technical factors have been identified. Nucleus CI532 is a Slim Modiolar electrode profile that is close to the modiolus, so it is expected to have a lower endocochlear hydrodynamic load since it lies in the covering of the osseus spiral lamina, thus less influencing the dynamics of the basilar membrane. However, the perimodiolar location of the electrode array allows the adjacent nerve elements of the spiral ganglion to be stimulated with a lower electrical intensity and a reduced surface that may be neuroprotective. Preservation of acoustic residual hearing following cochlear implantation improves the patient’s speech perception and the sound localization skills, particularly in difficult circumstances. Long-term residual hearing preservation may also be of great importance in the subsequent feasibility for regenerative procedures and drug treatments. Orv Hetil. 2018; 159(41): 1680–1688.

scholarly journals Spiral ganglion cells and macrophages initiate neuro-inflammation and scarring following cochlear implantation

2015 ◽  
Vol 9 ◽  
Author(s):  
Esperanza Bas ◽  
Stefania Goncalves ◽  
Michelle Adams ◽  
Christine T. Dinh ◽  
Jose M. Bas ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Neuro Inflammation
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