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Pinyon JL, von Jonquieres G, Crawford EN, Abed AA, Power JM, Klugmann M, Browne CJ, Housley DM, Wise AK, Fallon JB, Shepherd RK, Lin JY, McMahon C, McAlpine D, Birman CS, Lai W, Enke YL, Carter PM, Patrick JF, Gay RD, Marie C, Scherman D, Lovell NH, Housley GD. Gene Electrotransfer via Conductivity-Clamped Electric Field Focusing Pivots Sensori-Motor DNA Therapeutics: "A Spoonful of Sugar Helps the Medicine Go Down". ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2401392. [PMID: 38874431 DOI: 10.1002/advs.202401392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/20/2024] [Indexed: 06/15/2024]
Abstract
Viral vectors and lipofection-based gene therapies have dispersion-dependent transduction/transfection profiles that thwart precise targeting. The study describes the development of focused close-field gene electrotransfer (GET) technology, refining spatial control of gene expression. Integration of fluidics for precise delivery of "naked" plasmid deoxyribonucleic acid (DNA) in sucrose carrier within the focused electric field enables negative biasing of near-field conductivity ("conductivity-clamping"-CC), increasing the efficiency of plasma membrane molecular translocation. This enables titratable gene delivery with unprecedently low charge transfer. The clinic-ready bionics-derived CC-GET device achieved neurotrophin-encoding miniplasmid DNA delivery to the cochlea to promote auditory nerve regeneration; validated in deafened guinea pig and cat models, leading to improved central auditory tuning with bionics-based hearing. The performance of CC-GET is evaluated in the brain, an organ problematic for pulsed electric field-based plasmid DNA delivery, due to high required currents causing Joule-heating and damaging electroporation. Here CC-GET enables safe precision targeting of gene expression. In the guinea pig, reporter expression is enabled in physiologically critical brainstem regions, and in the striatum (globus pallidus region) delivery of a red-shifted channelrhodopsin and a genetically-encoded Ca2+ sensor, achieved photoactivated neuromodulation relevant to the treatment of Parkinson's Disease and other focal brain disorders.
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Affiliation(s)
- Jeremy L Pinyon
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
- Charles Perkins Centre, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, 2006, Australia
| | - Georg von Jonquieres
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
| | - Edward N Crawford
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
| | - Amr Al Abed
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
| | - John M Power
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
| | - Matthias Klugmann
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
| | - Cherylea J Browne
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
- Medical Sciences, School of Science, Western Sydney University, Sydney, NSW, 2560, Australia
| | - David M Housley
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
| | - Andrew K Wise
- Bionics Institute, 384-388 Albert Street, East Melbourne, VIC, 3002, Australia
- Medical Bionics, Department of Otolaryngology, University of Melbourne, Melbourne, VIC, 3002, Australia
| | - James B Fallon
- Bionics Institute, 384-388 Albert Street, East Melbourne, VIC, 3002, Australia
- Medical Bionics, Department of Otolaryngology, University of Melbourne, Melbourne, VIC, 3002, Australia
| | - Robert K Shepherd
- Bionics Institute, 384-388 Albert Street, East Melbourne, VIC, 3002, Australia
- Medical Bionics, Department of Otolaryngology, University of Melbourne, Melbourne, VIC, 3002, Australia
| | - John Y Lin
- Tasmanian School of Medicine, University of Tasmania, Hobart, TAS, 7001, Australia
| | - Catherine McMahon
- Faculty of Medicine and Health Sciences, The Hearing Hub, Macquarie University, Sydney, 2109, Australia
| | - David McAlpine
- Faculty of Medicine and Health Sciences, The Hearing Hub, Macquarie University, Sydney, 2109, Australia
| | - Catherine S Birman
- Faculty of Medicine and Health Sciences, The Hearing Hub, Macquarie University, Sydney, 2109, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, 2006, Australia
- Department of Otolaryngology, Royal Prince Alfred Hospital, Camperdown, NSW, 2050, Australia
- NextSense, Royal Institute of Deaf and Blind Children, Gladesville, NSW, 2111, Australia
| | - Waikong Lai
- NextSense, Royal Institute of Deaf and Blind Children, Gladesville, NSW, 2111, Australia
| | - Ya Lang Enke
- Cochlear Limited, Macquarie University, University Avenue, Macquarie Park, NSW, 2109, Australia
| | - Paul M Carter
- Cochlear Limited, Macquarie University, University Avenue, Macquarie Park, NSW, 2109, Australia
| | - James F Patrick
- Cochlear Limited, Macquarie University, University Avenue, Macquarie Park, NSW, 2109, Australia
| | - Robert D Gay
- Cochlear Limited, Macquarie University, University Avenue, Macquarie Park, NSW, 2109, Australia
| | - Corinne Marie
- CNRS, Inserm, UTCBS, Université Paris Cité, Paris, F-75006, France
- Chimie ParisTech, Université PSL, Paris, 75005, France
| | - Daniel Scherman
- CNRS, Inserm, UTCBS, Université Paris Cité, Paris, F-75006, France
- Fondation Maladies Rares, 96 rue Didot, Paris, 75014, France
| | - Nigel H Lovell
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
| | - Gary D Housley
- Translational Neuroscience Facility, Department of Physiology, School of Biomedical Sciences, Graduate School of Biomedical Engineering, Tyree Institute for Health Engineering (IHealthE), UNSW, Sydney, NSW, 2052, Australia
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Schaefer S, Sladen M, Nichani J, Millward K, Lockley M, O'Driscoll M, Kluk K, Bruce IA. Hearing preservation in paediatric cochlear implantation with the Nucleus Slim Straight Electrode - our experience. Int J Audiol 2024:1-8. [PMID: 38319187 DOI: 10.1080/14992027.2024.2306191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 01/11/2024] [Indexed: 02/07/2024]
Abstract
OBJECTIVE to evaluate the levels of successful hearing preservation and preservation of functional hearing following cochlear implantation (HPCI) in children using the Cochlear Nucleus® Slim Straight Electrode (SSE). DESIGN retrospective case note review of paediatric HPCI cases in our CI centre from 2013 to 2023. Inclusion criteria were attempted hearing preservation surgery, SSE used for implantation, pre-operative hearing thresholds ≤80dBHL at 250 Hz, CI before 18 years of age. Patients were excluded if no postoperative unaided PTA was obtained (poor attendance). Primairy outcome was hearing preservation using the HEARRING group formula; secondary outcome was residual functional hearing (≤80dBHL at 250 Hz/<90dB LFPTA). STUDY SAMPLE 56 patients with 94 CI's were included for review. RESULTS Hearing preservation was achieved in 94.7% (89/94) of ears and complete preservation in 72% (68/94)). Average functional hearing was preserved in 89% using both criteria for preservation. Long-term follow up data was available for 36 ears (average 35.2 months), demonstrating 88.9% (32/36) complete preservation. CONCLUSION We have reliably achieved and maintained a high success rate of HPCI using the SSE in our paediatric population. The field of HPCI would benefit from unification of outcome reporting in order to optimise the evidence available to professionals, patients and their carers.
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Affiliation(s)
- Simone Schaefer
- Department of Paediatric Otolaryngology, Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Mark Sladen
- Richard Ramsden Centre for Auditory Implants, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Jaya Nichani
- Department of Paediatric Otolaryngology, Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Kerri Millward
- Richard Ramsden Centre for Auditory Implants, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Morag Lockley
- Richard Ramsden Centre for Auditory Implants, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Martin O'Driscoll
- Richard Ramsden Centre for Auditory Implants, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Karolina Kluk
- Manchester Centre for Audiology and Deafness (ManCAD), Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Iain A Bruce
- Department of Paediatric Otolaryngology, Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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3
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Gunewardene N, Ma Y, Lam P, Wagstaff S, Cortez-Jugo C, Hu Y, Caruso F, Richardson RT, Wise AK. Developing the supraparticle technology for round window-mediated drug administration into the cochlea. J Control Release 2023; 361:621-635. [PMID: 37572963 DOI: 10.1016/j.jconrel.2023.08.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 08/14/2023]
Abstract
The semi-permeable round window membrane (RWM) is the gateway to the cochlea. Although the RWM is considered a minimally invasive and clinically accepted route for localised drug delivery to the cochlea, overcoming this barrier is challenging, hindering development of effective therapies for hearing loss. Neurotrophin 3 (NT3) is an emerging treatment option for hearing loss, but its therapeutic effect relies on sustained delivery across the RWM into the cochlea. Silica supraparticles (SPs) are drug delivery carriers capable of providing long-term NT3 delivery, when injected directly into the guinea pig cochlea. However, for clinical translation, a RWM delivery approach is desirable. Here, we aimed to test approaches to improve the longevity and biodistribution of NT3 inside the cochlea after RWM implantation of SPs in guinea pigs and cats. Three approaches were tested (i) coating the SPs to slow drug release (ii) improving the retention of SPs on the RWM using a clinically approved gel formulation and (iii) permeabilising the RWM with hyaluronic acid. A radioactive tracer (iodine 125: 125I) tagged to NT3 (125I NT3) was loaded into the SPs to characterise drug pharmacokinetics in vitro and in vivo. The neurotrophin-loaded SPs were coated using a chitosan and alginate layer-by-layer coating strategy, named as '(Chi/Alg)SPs', to promote long term drug release. The guinea pigs were implanted with 5× 125I NT3 loaded (Chi/Alg) SPs on the RWM, while cats were implanted with 30× (Chi/Alg) SPs. A cohort of animals were also implanted with SPs (controls). We found that the NT3 loaded (Chi/Alg)SPs exhibited a more linear release profile compared to NT3 loaded SPs alone. The 125I NT3 loaded (Chi/Alg)SPs in fibrin sealant had efficient drug loading (~5 μg of NT3 loaded per SP that weights ~50 μg) and elution capacities (~49% over one month) in vitro. Compared to the SPs in fibrin sealant, the (Chi/Alg)SPs in fibrin sealant had a significantly slower 125I NT3 drug release profile over the first 7 days in vitro (~12% for (Chi/Alg) SPs in fibrin sealant vs ~43% for SPs in fibrin sealant). One-month post-implantation of (Chi/Alg) SPs, gamma count measurements revealed an average of 0.3 μg NT3 remained in the guinea pig cochlea, while for the cat, 1.3 μg remained. Histological analysis of cochlear tissue revealed presence of a 125I NT3 signal localised in the basilar membrane of the lower basal turn in some cochleae after 4 weeks in guinea pigs and 8 weeks in cats. Comparatively, and in contrast to the in vitro release data, implantation of the SPs presented better NT3 retention and distribution inside the cochlea in both the guinea pigs and cats. No significant difference in drug entry was observed upon acute treatment of the RWM with hyaluronic acid. Collectively, our findings indicate that SPs and (Chi/Alg)SPs can facilitate drug transfer across the RWM, with detectable levels inside the cat cochlea even after 8 weeks with the intracochlear approach. This is the first study to examine neurotrophin pharmacokinetics in the cochlea for such an extended period of times in these two animal species. Whilst promising, we note that outcomes between animals were variable, and opposing results were found between in vitro and in vivo release studies. These findings have important clinical ramifications, emphasising the need to understand the physical properties and mechanics of this complex barrier in parallel with the development of therapies for hearing loss.
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Affiliation(s)
- Niliksha Gunewardene
- Bionics Institute, East Melbourne, Victoria 3002, Australia; Department of Medical Bionics, The University of Melbourne, Fitzroy, Victoria 3065, Australia.
| | - Yutian Ma
- Bionics Institute, East Melbourne, Victoria 3002, Australia; Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Patrick Lam
- Bionics Institute, East Melbourne, Victoria 3002, Australia
| | | | - Christina Cortez-Jugo
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Yingjie Hu
- Bionics Institute, East Melbourne, Victoria 3002, Australia; Department of Medical Bionics, The University of Melbourne, Fitzroy, Victoria 3065, Australia; Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Frank Caruso
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Rachael T Richardson
- Bionics Institute, East Melbourne, Victoria 3002, Australia; Department of Medical Bionics, The University of Melbourne, Fitzroy, Victoria 3065, Australia; Department of Surgery (Otolaryngology), University of Melbourne, The Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria 3002, Australia
| | - Andrew K Wise
- Bionics Institute, East Melbourne, Victoria 3002, Australia; Department of Medical Bionics, The University of Melbourne, Fitzroy, Victoria 3065, Australia.
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4
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Pisani A, Paciello F, Del Vecchio V, Malesci R, De Corso E, Cantone E, Fetoni AR. The Role of BDNF as a Biomarker in Cognitive and Sensory Neurodegeneration. J Pers Med 2023; 13:jpm13040652. [PMID: 37109038 PMCID: PMC10140880 DOI: 10.3390/jpm13040652] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/04/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) has a crucial function in the central nervous system and in sensory structures including olfactory and auditory systems. Many studies have highlighted the protective effects of BDNF in the brain, showing how it can promote neuronal growth and survival and modulate synaptic plasticity. On the other hand, conflicting data about BDNF expression and functions in the cochlear and in olfactory structures have been reported. Several clinical and experimental research studies showed alterations in BDNF levels in neurodegenerative diseases affecting the central and peripheral nervous system, suggesting that BDNF can be a promising biomarker in most neurodegenerative conditions, including Alzheimer's disease, shearing loss, or olfactory impairment. Here, we summarize current research concerning BDNF functions in brain and in sensory domains (olfaction and hearing), focusing on the effects of the BDNF/TrkB signalling pathway activation in both physiological and pathological conditions. Finally, we review significant studies highlighting the possibility to target BDNF as a biomarker in early diagnosis of sensory and cognitive neurodegeneration, opening new opportunities to develop effective therapeutic strategies aimed to counteract neurodegeneration.
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Affiliation(s)
- Anna Pisani
- Department of Otolaryngology Head and Neck Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Fabiola Paciello
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Valeria Del Vecchio
- Department of Neuroscience, Reproductive Sciences and Dentistry-Audiology Section, University of Naples Federico II, 80131 Naples, Italy
| | - Rita Malesci
- Department of Neuroscience, Reproductive Sciences and Dentistry-Audiology Section, University of Naples Federico II, 80131 Naples, Italy
| | - Eugenio De Corso
- Department of Otolaryngology Head and Neck Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Elena Cantone
- Department of Neuroscience, Reproductive Sciences and Dentistry-ENT Section, University of Naples Federico II, 80131 Naples, Italy
| | - Anna Rita Fetoni
- Department of Neuroscience, Reproductive Sciences and Dentistry-Audiology Section, University of Naples Federico II, 80131 Naples, Italy
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5
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Liao M, Hu Y, Zhang Y, Wang K, Fang Q, Qi Y, Shen Y, Cheng H, Fu X, Tang M, Sun S, Gao X, Chai R. 3D Ti 3C 2T x MXene-Matrigel with Electroacoustic Stimulation to Promote the Growth of Spiral Ganglion Neurons. ACS NANO 2022; 16:16744-16756. [PMID: 36222600 PMCID: PMC9620407 DOI: 10.1021/acsnano.2c06306] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cochlear implantation has become the most effective treatment method for patients with profound and total hearing loss. However, its therapeutic efficacy is dependent on the number and normal physiological function of cochlear implant-targeted spiral ganglion neurons (SGNs). Electrical stimulation can be used as an effective cue to regulate the morphology and function of excitatory cells. Therefore, it is important to develop an efficient cochlear implant electroacoustic stimulation (EAS) system to study the behavior of SGNs. In this work, we present an electrical stimulation system constructed by combining a cochlear implant and a conductive Ti3C2Tx MXene-matrigel hydrogel. SGNs were cultured in the Ti3C2Tx MXene-matrigel hydrogel and exposed to electrical stimulation transduced by the cochlear implant. It was demonstrated that low-frequency stimulation promoted the growth cone development and neurite outgrowth of SGNs as well as signal transmission between cells. This work may have potential value for the clinical application of the Ti3C2Tx MXene hydrogel to optimize the postoperative listening effect of cochlear implantation and benefit people with sensorineural hearing loss.
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Affiliation(s)
- Menghui Liao
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
- Department
of Otorhinolaryngology−Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008, China
| | - Yangnan Hu
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
- Department
of Otorhinolaryngology−Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008, China
| | - Yuhua Zhang
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
| | - Kaichen Wang
- Chien-Shiung
Wu College, Southeast University, Nanjing, Jiangsu 210096, China
| | - Qiaojun Fang
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
| | - Yanru Qi
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
| | - Yingbo Shen
- Chien-Shiung
Wu College, Southeast University, Nanjing, Jiangsu 210096, China
| | - Hong Cheng
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
| | - Xiaolong Fu
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
| | - Mingliang Tang
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
- Institute for Cardiovascular Science and Department of Cardiovascular Surgery of the First Affiliated
Hospital, Medical College, Soochow University, Suzhou, Jiangsu 215000, China
- Co-Innovation
Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Shan Sun
- ENT
Institute and Department
of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory
of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
| | - Xia Gao
- Department
of Otorhinolaryngology−Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008, China
| | - Renjie Chai
- State
Key Laboratory of Bioelectronics, Department of Otolaryngology Head
and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology,
Advanced Institute for Life and Health, Jiangsu Province High-Tech
Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China
- Co-Innovation
Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department
of Otolaryngology−Head and Neck Surgery, Sichuan Provincial
People’s Hospital, University of
Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Institute
for Stem Cell and Regeneration, Chinese
Academy of Science, Beijing 100101, China
- Beijing
Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing 100069, China
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6
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Rahman MT, Chari DA, Ishiyama G, Lopez I, Quesnel AM, Ishiyama A, Nadol JB, Hansen MR. Cochlear implants: Causes, effects and mitigation strategies for the foreign body response and inflammation. Hear Res 2022; 422:108536. [PMID: 35709579 PMCID: PMC9684357 DOI: 10.1016/j.heares.2022.108536] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 04/20/2022] [Accepted: 05/23/2022] [Indexed: 12/15/2022]
Abstract
Cochlear implants provide effective auditory rehabilitation for patients with severe to profound sensorineural hearing loss. Recent advances in cochlear implant technology and surgical approaches have enabled a greater number of patients to benefit from this technology, including those with significant residual low frequency acoustic hearing. Nearly all cochleae implanted with a cochlear implant electrode array develop an inflammatory and fibrotic response. This tissue reaction can have deleterious consequences for implant function, residual acoustic hearing, and the development of the next generation of cochlear prosthetics. This article reviews the current understanding of the inflammatory/foreign body response (FBR) after cochlear implant surgery, its impact on clinical outcome, and therapeutic strategies to mitigate this response. Findings from both in human subjects and animal models across a variety of species are highlighted. Electrode array design, surgical techniques, implant materials, and the degree and type of electrical stimulation are some critical factors that affect the FBR and inflammation. Modification of these factors and various anti-inflammatory pharmacological interventions have been shown to mitigate the inflammatory/FBR response. Ongoing and future approaches that seek to limit surgical trauma and curb the FBR to the implanted biomaterials of the electrode array are discussed. A better understanding of the anatomical, cellular and molecular basis of the inflammatory/FBR response after cochlear implantation has the potential to improve the outcome of current cochlear implants and also facilitate the development of the next generation of neural prostheses.
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Affiliation(s)
- Muhammad T Rahman
- Department of Otolaryngology-Head & Neck Surgery, University of Iowa, Iowa City, IA, USA
| | - Divya A Chari
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Gail Ishiyama
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Ivan Lopez
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Alicia M Quesnel
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Akira Ishiyama
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Joseph B Nadol
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Marlan R Hansen
- Department of Otolaryngology-Head & Neck Surgery, University of Iowa, Iowa City, IA, USA.
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7
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Bridging the electrode-neuron gap: finite element modeling of in vitro neurotrophin gradients to optimize neuroelectronic interfaces in the inner ear. Acta Biomater 2022; 151:360-378. [PMID: 36007779 DOI: 10.1016/j.actbio.2022.08.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/13/2022] [Accepted: 08/16/2022] [Indexed: 11/23/2022]
Abstract
Although cochlear implant (CI) technology has allowed for the partial restoration of hearing over the last few decades, persistent challenges (e.g., poor performance in noisy environments and limited ability to decode intonation and music) remain. The "electrode-neuron gap" is inherent to these challenges and poses the most significant obstacle to advancing past the current plateau in CI performance. We propose the development of a "neuro-regenerative nexus"-a biological interface that doubly preserves native spiral ganglion neurons (SGNs) while precisely directing the growth of neurites arising from transplanted human pluripotent stem cell (hPSC)-derived otic neuronal progenitors (ONPs) toward the native SGN population. We hypothesized that the Polyhedrin Delivery System (PODS®-recombinant human brain-derived neurotrophic factor [rhBDNF]) could stably provide the adequate BDNF concentration gradient to hPSC-derived late-stage ONPs to facilitate otic neuronal differentiation and directional neurite outgrowth. To test this hypothesis, a finite element model (FEM) was constructed to simulate BDNF concentration profiles generated by PODS®-rhBDNF based on initial concentration and culture device geometry. For biological validation of the FEM, cell culture experiments assessing survival, differentiation, neurite growth direction, and synaptic connections were conducted using a multi-chamber microfluidic device. We were able to successfully generate the optimal BDNF concentration gradient to enable survival, neuronal differentiation toward SGNs, directed neurite extension of hPSC-derived SGNs, and synaptogenesis between two hPSC-derived SGN populations. This proof-of-concept study provides a step toward the next generation of CI technology. STATEMENT OF SIGNIFICANCE: Our study demonstrates that the generation of in vitro neurotrophin concentration gradients facilitates survival, neuronal differentiation toward auditory neurons, and directed neurite extension of human pluripotent stem cell-derived auditory neurons. These findings are indispensable to designing a bioactive cochlear implant, in which stem cell-derived neurons are integrated into a cochlear implant electrode strip, as the strategy will confer directional neurite growth from the transplanted cells in the inner ear. This study is the first to present the concept of a "neuro-regenerative nexus" congruent with a bioactive cochlear implant to eliminate the electrode-neuron gapthe most significant barrier to next-generation cochlear implant technology.
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Abstract
INTRODUCTION More than 5% of the world's population have a disabling hearing loss which can be managed by hearing aids or implanted electrical devices. However, outcomes are highly variable, and the sound perceived by recipients is far from perfect. Sparked by the discovery of progenitor cells in the cochlea and rapid progress in drug delivery to the cochlea, biological and pharmaceutical therapies are currently in development to improve the function of the cochlear implant or eliminate the need for it altogether. AREAS COVERED This review highlights progress in emerging regenerative strategies to restore hearing and adjunct therapies to augment the cochlear implant. Novel approaches include the reprogramming of progenitor cells to restore the sensory hair cell population in the cochlea, gene therapy and gene editing to treat hereditary and acquired hearing loss. A detailed review of optogenetics is also presented as a technique that could enable optical stimulation of the spiral ganglion neurons, replacing or complementing electrical stimulation. EXPERT OPINION Increasing evidence of substantial reversal of hearing loss in animal models, alongside rapid advances in delivery strategies to the cochlea and learnings from clinical trials will amalgamate into a biological or pharmaceutical therapy to replace or complement the cochlear implant.
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Affiliation(s)
- Elise Ajay
- Bionics Institute, East Melbourne, Victoria, Australia.,University of Melbourne, Department of Engineering
| | | | - Rachael Richardson
- Bionics Institute, East Melbourne, Victoria, Australia.,University of Melbourne, Medical Bionics Department, Parkville, Victoria, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), East Melbourne, Victoria, Australia
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9
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Schwieger J, Frisch AS, Rau TS, Lenarz T, Hügl S, Scheper V. 3D Printed Cell Culture Chamber for Testing the Effect of Pump-Based Chronic Drug Delivery on Inner Ear Tissue. Biomolecules 2022; 12:biom12040589. [PMID: 35454178 PMCID: PMC9032916 DOI: 10.3390/biom12040589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/11/2022] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
Cochlear hair cell damage and spiral ganglion neuron (SGN) degeneration are the main causes of sensory neural hearing loss. Cochlear implants (CIs) can replace the function of the hair cells and stimulate the SGNs electrically. The condition of the SGNs and their spatial distance to the CI are key factors for CI-functionality. For a better performance, a high number of neurons and a closer contact to the electrode are intended. Neurotrophic factors are able to enhance SGN survival and neurite outgrowth, and thereby might optimize the electrode-nerve interaction. This would require chronic factor treatment, which is not yet established for the inner ear. Investigations on chronic drug delivery to SGNs could benefit from an appropriate in vitro model. Thus, an inner ear inspired Neurite Outgrowth Chamber (NOC), which allows the incorporation of a mini-osmotic pump for long-term drug delivery, was designed and three-dimensionally printed. The NOC’s function was validated using spiral ganglion explants treated with ciliary neurotrophic factor, neurotrophin-3, or control fluid released via pumps over two weeks. The NOC proved to be suitable for explant cultivation and observation of pump-based drug delivery over the examined period, with neurotrophin-3 significantly increasing neurite outgrowth compared to the other groups.
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Affiliation(s)
- Jana Schwieger
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
- Correspondence: ; Tel.: +49-5115327262
| | - Anna Sophie Frisch
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
| | - Thomas S. Rau
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Silke Hügl
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Verena Scheper
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
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10
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Wille I, Harre J, Oehmichen S, Lindemann M, Menzel H, Ehlert N, Lenarz T, Warnecke A, Behrens P. Development of Neuronal Guidance Fibers for Stimulating Electrodes: Basic Construction and Delivery of a Growth Factor. Front Bioeng Biotechnol 2022; 10:776890. [PMID: 35141211 PMCID: PMC8819688 DOI: 10.3389/fbioe.2022.776890] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/05/2022] [Indexed: 12/03/2022] Open
Abstract
State-of-the-art treatment for sensorineural hearing loss is based on electrical stimulation of residual spiral ganglion neurons (SGNs) with cochlear implants (CIs). Due to the anatomical gap between the electrode contacts of the CI and the residual afferent fibers of the SGNs, spatial spreading of the stimulation signal hampers focused neuronal stimulation. Also, the efficiency of a CI is limited because SGNs degenerate over time due to loss of trophic support. A promising option to close the anatomical gap is to install fibers as artificial nerve guidance structures on the surface of the implant and install on these fibers drug delivery systems releasing neuroprotective agents. Here, we describe the first steps in this direction. In the present study, suture yarns made of biodegradable polymers (polyglycolide/poly-ε-caprolactone) serve as the basic fiber material. In addition to the unmodified fiber, also fibers modified with amine groups were employed. Cell culture investigations with NIH 3T3 fibroblasts attested good cytocompatibility to both types of fibers. The fibers were then coated with the extracellular matrix component heparan sulfate (HS) as a biomimetic of the extracellular matrix. HS is known to bind, stabilize, modulate, and sustainably release growth factors. Here, we loaded the HS-carrying fibers with the brain-derived neurotrophic factor (BDNF) which is known to act neuroprotectively. Release of this neurotrophic factor from the fibers was followed over a period of 110 days. Cell culture investigations with spiral ganglion cells, using the supernatants from the release studies, showed that the BDNF delivered from the fibers drastically increased the survival rate of SGNs in vitro. Thus, biodegradable polymer fibers with attached HS and loaded with BDNF are suitable for the protection and support of SGNs. Moreover, they present a promising base material for the further development towards a future neuronal guiding scaffold.
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Affiliation(s)
- Inga Wille
- Institut für Anorganische Chemie, Leibniz Universität Hannover, Hannover, Germany
- Cluster of Excellence Hearing4all, Hannover, Germany
- *Correspondence: Inga Wille, ; Peter Behrens,
| | - Jennifer Harre
- Cluster of Excellence Hearing4all, Hannover, Germany
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany
| | - Sarah Oehmichen
- Institut für Technische Chemie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Maren Lindemann
- Institut für Technische Chemie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Henning Menzel
- Institut für Technische Chemie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Nina Ehlert
- Institut für Anorganische Chemie, Leibniz Universität Hannover, Hannover, Germany
- Cluster of Excellence Hearing4all, Hannover, Germany
| | - Thomas Lenarz
- Cluster of Excellence Hearing4all, Hannover, Germany
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany
| | - Athanasia Warnecke
- Cluster of Excellence Hearing4all, Hannover, Germany
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany
| | - Peter Behrens
- Institut für Anorganische Chemie, Leibniz Universität Hannover, Hannover, Germany
- Cluster of Excellence Hearing4all, Hannover, Germany
- Cluster of Excellence PhoenixD, Hannover, Germany
- *Correspondence: Inga Wille, ; Peter Behrens,
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11
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Gunewardene N, Lam P, Ma Y, Caruso F, Wagstaff S, Richardson RT, Wise AK. Pharmacokinetics and biodistribution of supraparticle-delivered neurotrophin 3 in the guinea pig cochlea. J Control Release 2022; 342:295-307. [PMID: 34999140 DOI: 10.1016/j.jconrel.2021.12.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 12/29/2021] [Indexed: 02/06/2023]
Abstract
Hearing loss is the most prevalent sensory disorder affecting nearly half a billion people worldwide. Aside from devices to assist hearing, such as hearing aids and cochlear implants, a drug treatment for hearing loss has yet to be developed. The neurotrophin family of growth factors has long been established as a potential therapy, however delivery of these factors into the inner ear at therapeutic levels over a sustained period of time has remained a challenge restricting clinical translation. We previously demonstrated that direct delivery of exogenous neurotrophin-3 (NT3) in the guinea pig cochleae via a bolus injection was rapidly cleared from the inner ear, with almost complete elimination 3 days post-treatment. Here, we explored the potential of suprapaticles (SPs) for NT3 delivery to the inner ear to achieve sustained delivery over time. SPs are porous spheroid structures comprised of smaller colloidal silica nanoparticles that provide a platform for long-term controlled release of therapeutics. This study aimed to assess the pharmacokinetics and biodistribution of SP-delivered NT3. We used a radioactive tracer (iodine 125: 125I) to label the NT3 to determine the loading, retention and distribution of NT3 delivered via SPs. Gamma measurements taken from 125I NT3 loaded SPs revealed high drug loading (an average of 5.3 μg of NT3 loaded per SP weighing 50 μg) and elution capacities in vitro (67% cumulative release over one month). Whole cochlear gamma measurements from SP-implanted cochleae harvested at various time points revealed detection of 125I NT3 in the guinea pig cochlea after one month, with 3.6 and 10% of the loaded drug remaining in the intracochlear and round window-implanted cochleae respectively. Autoradiography analysis of cochlear micro-sections revealed widespread 125I NT3 distribution after intracochlear SP delivery, but more restricted distribution with the round window delivery approach. Collectively, drug delivery into the inner ear using SPs support sustained, long-term availability and release of neurotrophins in the inner ear.
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Affiliation(s)
- Niliksha Gunewardene
- Bionics Institute, Melbourne, Australia; Medical Bionics Department, University of Melbourne, Australia.
| | | | - Yutian Ma
- Bionics Institute, Melbourne, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Frank Caruso
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | | | - Rachael T Richardson
- Bionics Institute, Melbourne, Australia; Medical Bionics Department, University of Melbourne, Australia; Department of Surgery (Otolaryngology), University of Melbourne, Australia
| | - Andrew K Wise
- Bionics Institute, Melbourne, Australia; Medical Bionics Department, University of Melbourne, Australia; Department of Surgery (Otolaryngology), University of Melbourne, Australia.
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12
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Zhang L, Chen S, Sun Y. Mechanism and Prevention of Spiral Ganglion Neuron Degeneration in the Cochlea. Front Cell Neurosci 2022; 15:814891. [PMID: 35069120 PMCID: PMC8766678 DOI: 10.3389/fncel.2021.814891] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 12/09/2021] [Indexed: 12/14/2022] Open
Abstract
Sensorineural hearing loss (SNHL) is one of the most prevalent sensory deficits in humans, and approximately 360 million people worldwide are affected. The current treatment option for severe to profound hearing loss is cochlear implantation (CI), but its treatment efficacy is related to the survival of spiral ganglion neurons (SGNs). SGNs are the primary sensory neurons, transmitting complex acoustic information from hair cells to second-order sensory neurons in the cochlear nucleus. In mammals, SGNs have very limited regeneration ability, and SGN loss causes irreversible hearing loss. In most cases of SNHL, SGN damage is the dominant pathogenesis, and it could be caused by noise exposure, ototoxic drugs, hereditary defects, presbycusis, etc. Tremendous efforts have been made to identify novel treatments to prevent or reverse the damage to SGNs, including gene therapy and stem cell therapy. This review summarizes the major causes and the corresponding mechanisms of SGN loss and the current protection strategies, especially gene therapy and stem cell therapy, to promote the development of new therapeutic methods.
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Affiliation(s)
- Li Zhang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sen Chen
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu Sun
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Otorhinolaryngology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Yu Sun,
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13
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Radeloff A, Nada N, El Mahallawi T, Kolkaila E, Vollmer M, Rak K, Hagen R, Schendzielorz P. Transplantation of adipose-derived stromal cells protects functional and morphological auditory nerve integrity in a model of cochlear implantation. Neuroreport 2021; 32:776-782. [PMID: 33994529 DOI: 10.1097/wnr.0000000000001651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cochlear implants are considered the gold standard therapy for subjects with severe hearing loss and deafness. Cochlear implants bypass the damaged hair cells and directly stimulate spiral ganglion neurons (SGNs) of the auditory nerve. Hence, the presence of functional SGNs is crucial for speech perception in electric hearing with a cochlear implant. In deaf individuals, SGNs progressively degenerate due to the lack of neurotrophic support, normally provided by sensory cells of the inner ear. Adipose-derived stromal cells (ASCs) are known to produce neurotrophic factors. In a guinea pig model of sensory hearing loss and cochlear implantation, ASCs were autologously transplanted into the scala tympani prior to insertion of a cochlear implant on one side. Electrically evoked auditory brain stem responses (eABR) were recorded 8 weeks after cochlear implantation. At conclusion of the experiment, the cochleae were histologically evaluated. Compared to untreated control animals, transplantation of ASCs resulted in an increased number of SGNs and their peripheral neurites. In ASC-transplanted animals, mean eABR thresholds were lower and suprathreshold amplitudes larger, suggesting a larger population of intact auditory nerve fibers. Moreover, when compared to controls, amplitude-level functions of eABRs in ASC transplanted animals demonstrated steeper slopes in response to increasing interphase gaps (IPGs), indicative of better functionality of the auditory nerve. In summary, results suggest that transplantation of autologous ASCs into the deaf inner ear may have protective effects on the survival of SGNs and their peripheral processes and may thus contribute to long-term benefits in speech discrimination performance in cochlear implant subjects.
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Affiliation(s)
- Andreas Radeloff
- Division of Oto-Rhino-Laryngology, Head and Neck Surgery, Carl von Ossietzky-University
- Cluster of excellence "Hearing 4 All"
- Research Center Neurosensory Science, Oldenburg, Germany
| | - Nashwa Nada
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Tanta University Hospitals, Tanta, Egypt
| | - Trandil El Mahallawi
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Tanta University Hospitals, Tanta, Egypt
| | - Enaas Kolkaila
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Tanta University Hospitals, Tanta, Egypt
| | - Maike Vollmer
- Department of Otol-Rhino-Laryngology, Head and Neck Surgery, University Magdeburg and Leibniz Institute for Neurobiology, Magdeburg
| | - Kristen Rak
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, University of Würzburg, Germany
| | - Rudolf Hagen
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, University of Würzburg, Germany
| | - Philipp Schendzielorz
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, University of Würzburg, Germany
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14
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Nanocarriers for drug delivery to the inner ear: Physicochemical key parameters, biodistribution, safety and efficacy. Int J Pharm 2020; 592:120038. [PMID: 33159985 DOI: 10.1016/j.ijpharm.2020.120038] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/26/2022]
Abstract
Despite the high incidence of inner ear disorders, there are still no dedicated medications on the market. Drugs are currently administered by the intratympanic route, the safest way to maximize drug concentration in the inner ear. Nevertheless, therapeutic doses are ensured for only a few minutes/hours using drug solutions or suspensions. The passage through the middle ear barrier strongly depends on drug physicochemical characteristics. For the past 15 years, drug encapsulation into nanocarriers has been developed to overcome this drawback. Nanocarriers are well known to sustain drug release and protect it from degradation. In this review, in vivo studies are detailed concerning nanocarrier biodistribution, their pathway mechanisms in the inner ear and the resulting drug pharmacokinetics. Key parameters influencing nanocarrier biodistribution are identified and discussed: nanocarrier size, concentration, surface composition and shape. Recent advanced strategies that combine nanocarriers with hydrogels, specific tissue targeting or modification of the round window permeability (cell-penetrating peptide, magnetic delivery) are explored. Most of the nanocarriers appear to be safe for the inner ear and provide a significant efficacy over classic formulations in animal models. However, many challenges remain to be overcome for future clinical applications.
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15
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Schulze J, Staecker H, Wedekind D, Lenarz T, Warnecke A. Expression pattern of brain-derived neurotrophic factor and its associated receptors: Implications for exogenous neurotrophin application. Hear Res 2020; 413:108098. [PMID: 33143996 DOI: 10.1016/j.heares.2020.108098] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/24/2020] [Accepted: 10/19/2020] [Indexed: 01/20/2023]
Abstract
The application of neurotrophins such as brain-derived neurotrophic factor (BDNF) is a promising pharmacological approach in cochlear implant research. Several in vitro and in vivo studies demonstrated that treatment with neurotrophins support the spiral ganglion neuron (SGN) survival and the synapses. Of the more than 40 companies that are working in the field of inner ear therapeutics, only one company is currently advancing BDNF towards clinical translation. Thus, there are no approved clinical therapies with neurotrophins, their precursors or neurotrophin-like substances. For a better understanding of the mechanisms of BDNF in the inner ear, we analysed the expression of mature BDNF (mBDNF), its pro-form proBDNF and their respective receptors the low affinity p75 neurotrophin receptor (p75NTR) and the neurotrophic receptor tyrosine kinase 2 (NTRK2). In the adult murine inner ear, mBDNF is expressed in the inner and outer hair cells (IHC and OHC) of the organ of Corti and in the spiral ganglion of the Rosenthal's canal, whereas proBDNF is only detected in the supporting cells below the OHC. The corresponding receptors NTRK2 and p75NTR are expressed in the spiral ganglion whereof p75NTR is stronger expressed. For more insights in the effects of mBDNF and proBDNF on inner ear specific cells, we treated primary dissociated SGN with different concentrations of mBDNF and proBDNF alone and in combination. Interestingly, treatment with proBDNF is not toxic for SGN but simultaneously not protective. However, combined treatment of mBDNF and proBDNF maintained and perhaps slightly increased the protective effect of mBDNF. Thus, the mixture of mBDNF and proBDNF could be the new direction for the development of BDNF-based therapeutics in cochlear implantation and could represent more precisely the natural environment.
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Affiliation(s)
- Jennifer Schulze
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany; Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1).
| | - Hinrich Staecker
- Department of Otolaryngology Head and Neck Surgery, University of Kansas School of Medicine, Kansas City, Kansas, USA
| | - Dirk Wedekind
- Department of experimental animal science, Hannover Medical School, Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany; Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1)
| | - Athanasia Warnecke
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany; Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1)
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16
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Consecutive Treatment with Brain-Derived Neurotrophic Factor and Electrical Stimulation Has a Protective Effect on Primary Auditory Neurons. Brain Sci 2020; 10:brainsci10080559. [PMID: 32824176 PMCID: PMC7464901 DOI: 10.3390/brainsci10080559] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 01/27/2023] Open
Abstract
Degeneration of neurons, such as the inner ear spiral ganglion neurons (SGN), may be decelerated or even stopped by neurotrophic factor treatment, such as brain-derived neurotrophic factor (BDNF), as well as electrical stimulation (ES). In a clinical setting, drug treatment of the SGN could start directly during implantation of a cochlear implant, whereas electrical stimulation begins days to weeks later. The present study was conducted to determine the effects of consecutive BDNF and ES treatments on SGN density and electrical responsiveness. An electrode drug delivery device was implanted in guinea pigs 3 weeks after deafening and five experimental groups were established: two groups received intracochlear infusion of artificial perilymph (AP) or BDNF; two groups were treated with AP respectively BDNF in addition to ES (AP + ES, BDNF + ES); and one group received BDNF from the day of implantation until day 34 followed by ES (BDNF ⇨ ES). Electrically evoked auditory brainstem responses were recorded. After one month of treatment, the tissue was harvested and the SGN density was assessed. The results show that consecutive treatment with BDNF and ES was as successful as the simultaneous combined treatment in terms of enhanced SGN density compared to the untreated contralateral side but not in regard to the numbers of protected cells.
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Schwieger J, Hamm A, Gepp MM, Schulz A, Hoffmann A, Lenarz T, Scheper V. Alginate-encapsulated brain-derived neurotrophic factor-overexpressing mesenchymal stem cells are a promising drug delivery system for protection of auditory neurons. J Tissue Eng 2020; 11:2041731420911313. [PMID: 32341778 PMCID: PMC7168777 DOI: 10.1177/2041731420911313] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/08/2020] [Indexed: 12/23/2022] Open
Abstract
The cochlear implant outcome is possibly improved by brain-derived neurotrophic factor treatment protecting spiral ganglion neurons. Implantation of genetically modified mesenchymal stem cells may enable the required long-term brain-derived neurotrophic factor administration. Encapsulation of mesenchymal stem cells in ultra-high viscous alginate may protect the mesenchymal stem cells from the recipient’s immune system and prevent their uncontrolled migration. Alginate stability and survival of mesenchymal stem cells in alginate were evaluated. Brain-derived neurotrophic factor production was measured and its protective effect was analyzed in dissociated rat spiral ganglion neuron co-culture. Since the cochlear implant is an active electrode, alginate–mesenchymal stem cell samples were electrically stimulated and alginate stability and mesenchymal stem cell survival were investigated. Stability of ultra-high viscous-alginate and alginate–mesenchymal stem cells was proven. Brain-derived neurotrophic factor production was detectable and spiral ganglion neuron survival, bipolar morphology, and neurite outgrowth were increased. Moderate electrical stimulation did not affect the mesenchymal stem cell survival and their viability was good within the investigated time frame. Local drug delivery by ultra-high viscous-alginate-encapsulated brain-derived neurotrophic factor–overexpressing mesenchymal stem cells is a promising strategy to improve the cochlear implant outcome.
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Affiliation(s)
- Jana Schwieger
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany.,NIFE-Lower Saxony Centre for Biomedical Engineering, Implant Research and Development, Hannover, Germany
| | - Anika Hamm
- NIFE-Lower Saxony Centre for Biomedical Engineering, Implant Research and Development, Hannover, Germany.,Department of Orthopaedic Surgery, Hannover Medical School, Hannover, Germany
| | - Michael M Gepp
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany.,Fraunhofer Project Center for Stem Cell Process Engineering, Würzburg, Germany
| | - André Schulz
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | - Andrea Hoffmann
- NIFE-Lower Saxony Centre for Biomedical Engineering, Implant Research and Development, Hannover, Germany.,Department of Orthopaedic Surgery, Hannover Medical School, Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany.,NIFE-Lower Saxony Centre for Biomedical Engineering, Implant Research and Development, Hannover, Germany.,Cluster of Excellence Hearing4all, German Research Foundation, Hannover, Germany
| | - Verena Scheper
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany.,NIFE-Lower Saxony Centre for Biomedical Engineering, Implant Research and Development, Hannover, Germany.,Cluster of Excellence Hearing4all, German Research Foundation, Hannover, Germany
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18
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Leake PA, Akil O, Lang H. Neurotrophin gene therapy to promote survival of spiral ganglion neurons after deafness. Hear Res 2020; 394:107955. [PMID: 32331858 DOI: 10.1016/j.heares.2020.107955] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/16/2020] [Accepted: 03/26/2020] [Indexed: 12/13/2022]
Abstract
Hearing impairment is a major health and economic concern worldwide. Currently, the cochlear implant (CI) is the standard of care for remediation of severe to profound hearing loss, and in general, contemporary CIs are highly successful. But there is great variability in outcomes among individuals, especially in children, with many CI users deriving much less or even marginal benefit. Much of this variability is related to differences in auditory nerve survival, and there has been substantial interest in recent years in exploring potential therapies to improve survival of the cochlear spiral ganglion neurons (SGN) after deafness. Preclinical studies using osmotic pumps and other approaches in deafened animal models to deliver neurotrophic factors (NTs) directly to the cochlea have shown promising results, especially with Brain-Derived Neurotrophic Factor (BDNF). More recent studies have focused on the use of NT gene therapy to force expression of NTs by target cells within the cochlea. This could provide the means for a one-time treatment to promote long-term NT expression and improve neural survival after deafness. This review summarizes the evidence for the efficacy of exogenous NTs in preventing SGN degeneration after hearing loss and reviews the animal research to date suggesting that NT gene therapy can elicit long-term NT expression in the cochlea, resulting in significantly improved SGN and radial nerve fiber survival after deafness. In addition, we discuss NT gene therapy in other non-auditory applications and consider some of the remaining issues with regard to selecting optimal vectors, timing of treatment, and place/method of delivery, etc. that must be resolved prior to considering clinical application.
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Affiliation(s)
- Patricia A Leake
- S & I Epstein Laboratory, Dept. of Otolaryngology Head and Neck Surgery, University of California San Francisco, 2340 Sutter Street, Room N331, San Francisco, CA, 94115-1330, USA.
| | - Omar Akil
- S & I Epstein Laboratory, Dept. of Otolaryngology Head and Neck Surgery, University of California San Francisco, 2340 Sutter Street, Room N331, San Francisco, CA, 94115-1330, USA
| | - Hainan Lang
- Dept. of Pathology and Laboratory Medicine, Medical University of South Carolina, 165 Ashley Avenue, Room RS613, Charleston, SC, 29414, USA
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Increased Risk of Sensorineural Hearing Loss as a Result of Exposure to Air Pollution. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17061969. [PMID: 32192124 PMCID: PMC7143358 DOI: 10.3390/ijerph17061969] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/03/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022]
Abstract
Whether exposure to air pollution is associated with developing sensorineural hearing loss (SHL) remains controversial. Using data from the National Health Insurance Research Database, we recruited a total of 75,767 subjects aged older than 20 years with no history of SHL from 1998 to 2010, and they were followed up until SHL was observed, they withdrew from the National Health Insurance program, or the study ended. The subjects were evenly exposed to low-level, mid-level, and high-level carbon monoxide (CO) and nitrogen dioxide (NO2). The incidence rate ratio of SHL for patients exposed to high-level CO was 1.24 (95% confidence interval (CI) = 1.14–1.36). The NO2 pollutants increased the incidence rate ratios of SHL in mid-level NO2 and high-level NO2 exposures by 1.10 (95% CI = 1.10–1.32) and 1.36 (95% CI = 1.24–1.49) times, respectively. The adjusted hazard ratio (adj. HR) of SHL in patients exposed to high-level CO was 1.45 (95% CI = 1.31–1.59), relative to that of patients exposed to low-level CO. Compared to patients exposed to low-level NO2, patients exposed to mid-level NO2 (adj. HR = 1.40, 95% CI = 1.27–1.54) and high-level NO2 (adj. HR = 1.63, 95% CI = 1.48–1.81) had a higher risk of developing SHL. The increased risk of SHL following the increased concentrations of air pollutants (CO and NO2) was statistically significant in this study. In conclusion, the subjects’ exposure to air pollution exhibited a significantly higher risk of developing SHL in Taiwan.
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Hügl S, Scheper V, Gepp MM, Lenarz T, Rau TS, Schwieger J. Coating stability and insertion forces of an alginate-cell-based drug delivery implant system for the inner ear. J Mech Behav Biomed Mater 2019; 97:90-98. [DOI: 10.1016/j.jmbbm.2019.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/01/2019] [Accepted: 05/03/2019] [Indexed: 12/20/2022]
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Pinyon JL, von Jonquieres G, Crawford EN, Duxbury M, Al Abed A, Lovell NH, Klugmann M, Wise AK, Fallon JB, Shepherd RK, Birman CS, Lai W, McAlpine D, McMahon C, Carter PM, Enke YL, Patrick JF, Schilder AG, Marie C, Scherman D, Housley GD. Neurotrophin gene augmentation by electrotransfer to improve cochlear implant hearing outcomes. Hear Res 2019; 380:137-149. [DOI: 10.1016/j.heares.2019.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/07/2019] [Accepted: 06/12/2019] [Indexed: 12/14/2022]
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AAV-Mediated Neurotrophin Gene Therapy Promotes Improved Survival of Cochlear Spiral Ganglion Neurons in Neonatally Deafened Cats: Comparison of AAV2-hBDNF and AAV5-hGDNF. J Assoc Res Otolaryngol 2019; 20:341-361. [PMID: 31222416 PMCID: PMC6646500 DOI: 10.1007/s10162-019-00723-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 04/15/2019] [Indexed: 01/22/2023] Open
Abstract
Outcomes with contemporary cochlear implants (CI) depend partly upon the survival and condition of the cochlear spiral ganglion (SG) neurons. Previous studies indicate that CI stimulation can ameliorate SG neural degeneration after deafness, and brain-derived neurotrophic factor (BDNF) delivered by an osmotic pump can further improve neural survival. However, direct infusion of BDNF elicits undesirable side effects, and osmotic pumps are impractical for clinical application. In this study, we explored the potential for two adeno-associated viral vectors (AAV) to elicit targeted neurotrophic factor expression in the cochlea and promote improved SG and radial nerve fiber survival. Juvenile cats were deafened prior to hearing onset by systemic aminoglycoside injections. Auditory brainstem responses showed profound hearing loss by 16-18 days postnatal. At ~ 4 weeks of age, AAV2-GFP (green fluorescent protein), AAV5-GFP, AAV2-hBDNF, or AAV5-hGDNF (glial-derived neurotrophic factor) was injected through the round window unilaterally. For GFP immunofluorescence, animals were studied ~ 4 weeks post-injection to assess cell types transfected and their distributions. AAV2-GFP immunofluorescence demonstrated strong expression of the GFP reporter gene in residual inner (IHCs), outer hair cells (OHCs), inner pillar cells, and in some SG neurons throughout the cochlea. AAV5-GFP elicited robust transduction of IHCs and some SG neurons, but few OHCs and supporting cells. After AAV-neurotrophic factor injections, animals were studied ~ 3 months post-injection to evaluate neural survival. AAV5-hGDNF elicited a modest neurotrophic effect, with 6 % higher SG density, but had no trophic effect on radial nerve fiber survival, and undesirable ectopic fiber sprouting occurred. AAV2-hBDNF elicited a similar 6 % increase in SG survival, but also resulted in greatly improved radial nerve fiber survival, with no ectopic fiber sprouting. A further study assessed whether AAV2-hBDNF neurotrophic effects would persist over longer post-injection periods. Animals examined 6 months after virus injection showed substantial neurotrophic effects, with 14 % higher SG density and greatly improved radial nerve fiber survival. Our results suggest that AAV-neurotrophin gene therapy can elicit expression of physiological concentrations of neurotrophins in the cochlea, supporting improved SG neuronal and radial nerve fiber survival while avoiding undesirable side effects. These studies also demonstrate the potential for application of cochlear gene therapy in a large mammalian cochlea comparable to the human cochlea and in an animal model of congenital/early acquired deafness.
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Ma Y, Wise AK, Shepherd RK, Richardson RT. New molecular therapies for the treatment of hearing loss. Pharmacol Ther 2019; 200:190-209. [PMID: 31075354 DOI: 10.1016/j.pharmthera.2019.05.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022]
Abstract
An estimated 466 million people suffer from hearing loss worldwide. Sensorineural hearing loss is characterized by degeneration of key structures of the sensory pathway in the cochlea such as the sensory hair cells, the primary auditory neurons and their synaptic connection to the hair cells - the ribbon synapse. Various strategies to protect or regenerate these sensory cells and structures are the subject of intensive research. Yet despite recent advances in our understandings of the capacity of the cochlea for repair and regeneration there are currently no pharmacological or biological interventions for hearing loss. Current research focusses on localized cochlear drug, gene and cell-based therapies. One of the more promising drug-based therapies is based on neurotrophic factors for the repair of the ribbon synapse after noise exposure, as well as preventing loss of primary auditory neurons and regrowth of the auditory neuron fibers after severe hearing loss. Drug therapy delivery technologies are being employed to address the specific needs of neurotrophin and other therapies for hearing loss that include the need for high doses, long-term delivery, localised or cell-specific targeting and techniques for their safe and efficacious delivery to the cochlea. Novel biomaterials are enabling high payloads of drugs to be administered to the cochlea with subsequent slow-release properties that are proving to be beneficial for treating hearing loss. In parallel, new gene therapy technologies are addressing the need for cell specificity and high efficacy for the treatment of both genetic and acquired hearing loss with promising reports of hearing recovery. Some biomaterials and cell therapies are being used in conjunction with the cochlear implant ensuring therapeutic benefit to the primary neurons during electrical stimulation. This review will introduce the auditory system, hearing loss and the potential for repair and regeneration in the cochlea. Drug delivery to the cochlea will then be reviewed, with a focus on new biomaterials, gene therapy technologies, cell therapy and the use of the cochlear implant as a vehicle for drug delivery. With the current pre-clinical research effort into therapies for hearing loss, including clinical trials for gene therapy, the future for the treatment for hearing loss is looking bright.
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Affiliation(s)
- Yutian Ma
- Bionics Institute, East Melbourne, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Australia; University of Melbourne, Department of Chemical Engineering, Parkville, Victoria, Australia
| | - Andrew K Wise
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Robert K Shepherd
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Rachael T Richardson
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia.
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Liu W, Wang X, Wang M, Wang H. Protection of Spiral Ganglion Neurons and Prevention of Auditory Neuropathy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1130:93-107. [DOI: 10.1007/978-981-13-6123-4_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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Ye B, Wang Q, Hu H, Shen Y, Fan C, Chen P, Ma Y, Wu H, Xiang M. Restoring autophagic flux attenuates cochlear spiral ganglion neuron degeneration by promoting TFEB nuclear translocation via inhibiting MTOR. Autophagy 2019; 15:998-1016. [PMID: 30706760 PMCID: PMC6526833 DOI: 10.1080/15548627.2019.1569926] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Macroautophagy/autophagy dysfunction is associated with many neurodegenerative diseases. TFEB (transcription factor EB), an important molecule that regulates lysosomal and autophagy function, is regarded as a potential target for treating some neurodegenerative diseases. However, the relationship between autophagy dysfunction and spiral ganglion neuron (SGN) degeneration and the role of TFEB in SGN degeneration has not yet been established. Here, we showed that in degenerated SGNs, induced by sensory epithelial cell loss in the cochlea of mice following kanamycin and furosemide administration, the lipofuscin area and oxidative stress level were increased, the nuclear-to-cytoplasmic TFEB ratio was decreased, and the late stage of autophagic flux was impaired. After autophagy dysfunction was partially ameliorated with an MTOR inhibitor, which promoted TFEB translocation into the nucleus from the cytoplasm, we found that the lysosomal deficits were significantly relieved, the oxidative stress level was reduced, and the density of surviving SGNs and auditory nerve fibers was increased. The results in the present study reveal that autophagy dysfunction is an important component of SGN degeneration, and TFEB may be a potential target for attenuating SGN degeneration following sensory epithelial cell loss in the cochlea of mice. Abbreviations: 3-NT: 3-nitrotyrosine; 4-HNE: 4-hydroxynonenal; 8-OHdG: 8-hydroxy-2ʹ-deoxyguanosine; ABR: auditory brainstem response; APP: amyloid beta (A4) precursor protein; CLEAR: coordinated lysosomal expression and regulation; CTSB: cathespin B; CTSD: cathespin D; SAMR1: senescence-accelerated mouse/resistance 1; SAMP8: senescence-accelerated mouse/prone 8; MAPK1/ERK2: mitogen-activated protein kinase 1; MTOR: mechanistic target of rapamycin kinase; SGN: spiral ganglion neuron; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscope; TFEB: transcription factor EB
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Affiliation(s)
- Bin Ye
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Quan Wang
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Haixia Hu
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Yilin Shen
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Cui Fan
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Penghui Chen
- b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Yan Ma
- b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Hao Wu
- b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Mingliang Xiang
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
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Akil O, Blits B, Lustig LR, Leake PA. Virally Mediated Overexpression of Glial-Derived Neurotrophic Factor Elicits Age- and Dose-Dependent Neuronal Toxicity and Hearing Loss. Hum Gene Ther 2018; 30:88-105. [PMID: 30183384 DOI: 10.1089/hum.2018.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Contemporary cochlear implants (CI) are generally very effective for remediation of severe to profound sensorineural hearing loss, but outcomes are still highly variable. Auditory nerve survival is likely one of the major factors underlying this variability. Neurotrophin therapy therefore has been proposed for CI recipients, with the goal of improving outcomes by promoting improved survival of cochlear spiral ganglion neurons (SGN) and/or residual hair cells. Previous studies have shown that glial-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor, and neurotrophin-3 can rescue SGNs following insult. The current study was designed to determine whether adeno-associated virus vector serotype 5 (AAV-5) encoding either green fluorescent protein or GDNF can transduce cells in the mouse cochlea to express useful levels of neurotrophin and to approximate the optimum therapeutic dose(s) for transducing hair cells and SGN. The findings demonstrate that AAV-5 is a potentially useful gene therapy vector for the cochlea, resulting in extremely high levels of transgene expression in the cochlear inner hair cells and SGN. However, overexpression of human GDNF in newborn mice caused severe neurological symptoms and hearing loss, likely due to Purkinje cell loss and cochlear nucleus pathology. Thus, extremely high levels of transgene protein expression should be avoided, particularly for proteins that have neurological function in neonatal subjects.
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Affiliation(s)
- Omar Akil
- 1 Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California
| | - Bas Blits
- 2 Department of Research and Development, UniQure Biopharma B.V., Amsterdam, The Netherlands
| | - Lawrence R Lustig
- 3 Department of Otolaryngology-Head and Neck Surgery, Columbia University Medical Center, New York, New York
| | - Patricia A Leake
- 1 Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California
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Sriperumbudur KK, Pau HW, van Rienen U. Effect of Tissue Heterogeneity on the Transmembrane Potential of Type-1 Spiral Ganglion Neurons: A Simulation Study. IEEE Trans Biomed Eng 2018; 65:658-668. [DOI: 10.1109/tbme.2017.2700361] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Gao K, Ding D, Sun H, Roth J, Salvi R. Kanamycin Damages Early Postnatal, but Not Adult Spiral Ganglion Neurons. Neurotox Res 2017; 32:603-613. [PMID: 28656549 PMCID: PMC5711550 DOI: 10.1007/s12640-017-9773-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/31/2017] [Accepted: 06/13/2017] [Indexed: 01/13/2023]
Abstract
Although aminoglycoside antibiotics such as kanamycin are widely used clinically to treat life-threatening bacterial infections, ototoxicity remains a significant dose-limiting side effect. The prevailing view is that the hair cells are the primary ototoxic target of aminoglycosides and that spiral ganglion neurons begin to degenerate weeks or months after the hair cells have died due to lack of neurotrophic support. To test the early developmental aspects of this issue, we compared kanamycin-induced hair cell and spiral ganglion pathology in rat postnatal day 3 cochlear organotypic cultures with adult whole cochlear explants. In both adult and postnatal day 3 cultures, hair cell damage began at the base of the cochleae and progressed toward the apex in a dose-dependent manner. In postnatal day 3 cultures, spiral ganglion neurons were rapidly destroyed by kanamycin prior to hair cell loss. In contrast, adult spiral ganglion neurons were resistant to kanamycin damage even at the highest concentration, consistent with in vivo models of delayed SGN degeneration. In postnatal day 3 cultures, kanamycin preferentially damaged type I spiral ganglion neurons, whereas type II neurons were resistant. Spiral ganglion degeneration of postnatal day 3 neurons was associated with upregulation of the superoxide radical and caspase-3-mediated cell death. These results show for the first time that kanamycin is toxic to postnatal day 3 spiral ganglion neurons, but not adult neurons.
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Affiliation(s)
- Kelei Gao
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Hong Sun
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Jerome Roth
- Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan
| | - Richard Salvi
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China.
- Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan.
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Stimulation of synapse formation between stem cell-derived neurons and native brainstem auditory neurons. Sci Rep 2017; 7:13843. [PMID: 29062015 PMCID: PMC5653851 DOI: 10.1038/s41598-017-13764-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 09/11/2017] [Indexed: 01/05/2023] Open
Abstract
Integration of stem cell-derived cells into native cellular environment remains a challenge in the field. This study developed novel methods to co-culture neural stem cell-derived spiral ganglion-like neurons (ScNs) and mouse auditory cochlear nucleus (CN) neurons to understand whether ScNs of the peripheral nervous system (PNS) synapse with CN neurons of the central nervous system (CNS). ScNs were obtained from neural stem cells that were derived from transgenic mouse pre-labeled with enhanced green fluorescent protein (EGFP), whereas CN neurons were from postnatal mouse primary cultures. ScNs and CN neurons were co-cultured for 4–6 days in the absence or presence of astrocyte-conditioned medium (ACM). Class III β-tubulin (TUJ1)-expressing connections were found between ScNs and CN neurons. Expression of the synaptic vesicle marker SV2 was significantly increased along connections between ScNs and CN neurons in the presence of ACM. Immunodepletion and knockout studies indicated that thrombospodin-1 played an important role in ACM-exerted synaptogenic effects. Newly-generated synapse-like structures expressed glutamatergic marker VGluT1, pre- and post-synaptic proteins. Synaptic vesicle recycling studies suggested functional synaptic vesicle retrieval. These results reveal that stem cell-derived PNS neurons are able to form functional connections with native CNS neurons, which is critical for stem cell-based neural pathway regeneration.
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Schendzielorz P, Vollmer M, Rak K, Wiegner A, Nada N, Radeloff K, Hagen R, Radeloff A. Adipose-derived stromal cells enhance auditory neuron survival in an animal model of sensory hearing loss. Cytotherapy 2017; 19:1197-1207. [DOI: 10.1016/j.jcyt.2017.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 12/27/2022]
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Scheper V, Hessler R, Hütten M, Wilk M, Jolly C, Lenarz T, Paasche G. Local inner ear application of dexamethasone in cochlear implant models is safe for auditory neurons and increases the neuroprotective effect of chronic electrical stimulation. PLoS One 2017; 12:e0183820. [PMID: 28859106 PMCID: PMC5578571 DOI: 10.1371/journal.pone.0183820] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 08/11/2017] [Indexed: 01/15/2023] Open
Abstract
Dexamethasone (DEX) can reduce fibrous tissue growth as well as loss of residual hearing which may occur after cochlear implantation. Little is known about the effect of local inner ear DEX treatment on the spiral ganglion neurons (SGN), which are the target of the electrical stimulation with a cochlear implant (CI). Three different clinically relevant strategies of DEX-delivery into the inner ear were used. DEX was either eluted from the electrode carriers' silicone, released from a reservoir by passive diffusion, or actively applied using a pump based system. The effect of the locally applied DEX on SGN density, size and function was evaluated. DEX did not affect the SGN density compared to the relevant control groups. Simultaneously applied with chronic electrical stimulation (ES), DEX increased the neuroprotective effect of ES in the basal region and the hearing threshold tended to decrease. The EABR thresholds did not correlate with the relevant SGN density. When correlating the SGN number with fibrosis, no dependency was observed. DEX concentrations as applied in these animal models are safe for inner ear delivery in terms of their effect on SGN density. Additionally, DEX tends to improve the neuroprotective effect of chronic electrical stimulation by increasing the number of surviving neurons. This is an important finding in regard to clinical applications of DEX for local treatment of the inner ear in view of cochlear implantation and other applications.
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Affiliation(s)
- Verena Scheper
- Hannover Medical School (MHH), Department of Otolaryngology, Hannover, Germany
- Cluster of Excellence Hearing4all, German Research Foundation, Hannover, Germany
- * E-mail:
| | - Roland Hessler
- MED-EL Innsbruck, Research & Development, Innsbruck, Österreich
| | - Mareike Hütten
- Hannover Medical School (MHH), Department of Otolaryngology, Hannover, Germany
| | - Maciej Wilk
- Hannover Medical School (MHH), Department of Otolaryngology, Hannover, Germany
| | - Claude Jolly
- MED-EL Innsbruck, Research & Development, Innsbruck, Österreich
| | - Thomas Lenarz
- Hannover Medical School (MHH), Department of Otolaryngology, Hannover, Germany
- Cluster of Excellence Hearing4all, German Research Foundation, Hannover, Germany
| | - Gerrit Paasche
- Hannover Medical School (MHH), Department of Otolaryngology, Hannover, Germany
- Cluster of Excellence Hearing4all, German Research Foundation, Hannover, Germany
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Pfingst BE, Colesa DJ, Swiderski DL, Hughes AP, Strahl SB, Sinan M, Raphael Y. Neurotrophin Gene Therapy in Deafened Ears with Cochlear Implants: Long-term Effects on Nerve Survival and Functional Measures. J Assoc Res Otolaryngol 2017; 18:731-750. [PMID: 28776202 DOI: 10.1007/s10162-017-0633-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 07/04/2017] [Indexed: 01/05/2023] Open
Abstract
Because cochlear implants function by stimulating the auditory nerve, it is assumed that the condition of the nerve plays an important role in the efficacy of the prosthesis. Thus, considerable research has been devoted to methods of preserving the nerve following deafness. Neurotrophins have been identified as a potential contributor to neural health, but most of the research to date has been done in young animals and for short periods (less than 3 to 6 months) after the onset of treatment. The first objective of the current experiment was to examine the effects of a neurotrophin gene therapy delivery method on spiral ganglion neuron (SGN) preservation and function in the long term (5 to 14 months) in mature guinea pigs with cochlear implants. The second objective was to examine several potential non-invasive monitors of auditory nerve health following the neurotrophin gene therapy procedure. Eighteen mature adult male guinea pigs were deafened by cochlear perfusion of neomycin and then one ear was inoculated with an adeno-associated viral vector with an Nft3-gene insert (AAV.Ntf3) and implanted with a cochlear implant electrode array. Five control animals were deafened and inoculated with an empty AAV and implanted. Data from 43 other guinea pig ears from this and previous experiments were used for comparison: 24 animals implanted in a hearing ear, nine animals deafened and implanted with no inoculation, and ten normal-hearing non-implanted ears. After 4 to 21 months of psychophysical and electrophysiological testing, the animals were prepared for histological examination of SGN densities and inner hair cell (IHC) survival. Seventy-eight percent of the ears deafened and inoculated with AAV.Ntf3 showed better SGN survival than the 14 deafened-control ears. The degree of SGN preservation following the gene therapy procedure was variable across animals and across cochlear turns. Slopes of psychophysical multipulse integration (MPI) functions were predictive of SGN density, but only in animals with preserved IHCs. MPI was not affected by the AAV.Ntf3 treatment, but there was a minor improvement in temporal integration (TI). AAV.Ntf3 treatment had significant effects on ECAP and EABR amplitude growth func-tion (AGF) slopes; the reduction in slope in deafened ears was ameliorated by the AAV.Ntf3 treatment. Slopes of the ECAP and EABR AGFs were predictive of SGN density in a broad area near and just apical to the implant. The highest ensemble spontaneous activity (ESA) values were seen in animals with surviving IHCs, but AAV.Ntf3 treatment in deafened ears resulted in slightly higher ESA values compared to deafened untreated ears. Overall, a combination of the psychophysical and electrophysiological measures can be useful for monitoring the health of the implanted cochlea in guinea pigs. These measures should be applicable for assessing cochlear health in human subjects.
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Affiliation(s)
- Bryan E Pfingst
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI, 48109-5616, USA.
| | - Deborah J Colesa
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Donald L Swiderski
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Aaron P Hughes
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | | | - Moaz Sinan
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
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Encapsulated cell device approach for combined electrical stimulation and neurotrophic treatment of the deaf cochlea. Hear Res 2017; 350:110-121. [PMID: 28463804 DOI: 10.1016/j.heares.2017.04.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 03/15/2017] [Accepted: 04/23/2017] [Indexed: 12/21/2022]
Abstract
Profound hearing impairment can be overcome by electrical stimulation (ES) of spiral ganglion neurons (SGNs) via a cochlear implant (CI). Thus, SGN survival is critical for CI efficacy. Application of glial cell line-derived neurotrophic factor (GDNF) has been shown to reduce SGN degeneration following deafness. We tested a novel method for local, continuous GDNF-delivery in combination with ES via a CI. The encapsulated cell (EC) device contained a human ARPE-19 cell-line, genetically engineered for secretion of GDNF. In vitro, GDNF delivery was stable during ES delivered via a CI. In the chronic in vivo part, cats were systemically deafened and unilaterally implanted into the scala tympani with a CI and an EC device, which they wore for six months. The implantation of control devices (same cell-line not producing GDNF) had no negative effect on SGN survival. GDNF application without ES led to an unexpected reduction in SGN survival, however, the combination of GDNF with initial, short-term ES resulted in a significant protection of SGNs. A tight fibrous tissue formation in the scala tympani of the GDNF-only group is thought to be responsible for the increased SGN degeneration, due to mechanisms related to an aggravated foreign body response. Furthermore, the fibrotic encapsulation of the EC device led to cell death or cessation of GDNF release within the EC device during the six months in vivo. In both in vitro and in vivo, fibrosis was reduced by CI stimulation, enabling the neuroprotective effect of the combined treatment. Thus, fibrous tissue growth limits treatment possibilities with an EC device. For a stable and successful long-term neurotrophic treatment of the SGN via EC devices in human CI users, it would be necessary to make changes in the treatment approach (provision of anti-inflammatories), the EC device surface (reduced cell adhesion) and the ES (initiation prior to fibrosis formation).
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Eshraghi AA, Ahmed J, Krysiak E, Ila K, Ashman P, Telischi FF, Angeli S, Prentiss S, Martinez D, Valendia S. Clinical, surgical, and electrical factors impacting residual hearing in cochlear implant surgery. Acta Otolaryngol 2017; 137:384-388. [PMID: 27918225 DOI: 10.1080/00016489.2016.1256499] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
CONCLUSIONS This study recommends using soft surgical principal and round window insertion to protect residual hearing with favorable anatomical exposure. Further studies are needed to evaluate the impact of the electrical stimulation on the organ of corti and hearing. OBJECTIVE The objective of this study is to analyze various factors that impact on preservation of residual hearing post-implantation. METHODS A retrospective study was performed to analyze loss of residual hearing in a cohort of 225 patients implanted in a large academic center. Sixty-four patients met the inclusion criteria. The impact of age at implantation, gender, etiology of hearing loss, cochleostomy vs round window insertion, partial vs full insertion, and effect of initial stimulation were analyzed using appropriate statistical analysis. RESULTS The overall hearing preservation rate for all implanted patients was 64%. Loss of residual hearing was significantly more observed in cases of cochleostomy and/or non-soft surgical techniques. No correlation was observed with age at implantation, gender, side of implant, device manufacturer, and presence of pre-lingual deafness vs post-lingual, full or partial electrode insertion. In addition, there was a small but significant decrease in hearing between pre-stimulation and post-stimulation audiograms at 6000 Hz.
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Affiliation(s)
- Adrien A. Eshraghi
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jamal Ahmed
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Eric Krysiak
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Kadri Ila
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Peter Ashman
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Fred F. Telischi
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Simon Angeli
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sandra Prentiss
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Diane Martinez
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sandra Valendia
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
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Wise AK, Tan J, Wang Y, Caruso F, Shepherd RK. Improved Auditory Nerve Survival with Nanoengineered Supraparticles for Neurotrophin Delivery into the Deafened Cochlea. PLoS One 2016; 11:e0164867. [PMID: 27788219 PMCID: PMC5082918 DOI: 10.1371/journal.pone.0164867] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 10/03/2016] [Indexed: 11/23/2022] Open
Abstract
Cochlear implants electrically stimulate spiral ganglion neurons (SGNs) in order to provide speech cues to severe-profoundly deaf patients. In normal hearing cochleae the SGNs depend on endogenous neurotrophins secreted by sensory cells in the organ of Corti for survival. SGNs gradually degenerate following deafness and consequently there is considerable interest in developing clinically relevant strategies to provide exogenous neurotrophins to preserve SGN survival. The present study investigated the safety and efficacy of a drug delivery system for the cochlea using nanoengineered silica supraparticles. In the present study we delivered Brain-derived neurotrophic factor (BDNF) over a period of four weeks and evaluated SGN survival as a measure of efficacy. Supraparticles were bilaterally implanted into the basal turn of cochleae in profoundly deafened guinea pigs. One ear received BDNF-loaded supraparticles and the other ear control (unloaded) supraparticles. After one month of treatment the cochleae were examined histologically. There was significantly greater survival of SGNs in cochleae that received BDNF supraparticles compared to the contralateral control cochleae (repeated measures ANOVA, p = 0.009). SGN survival was observed over a wide extent of the cochlea. The supraparticles were well tolerated within the cochlea with a tissue response that was localised to the site of implantation in the cochlear base. Although mild, the tissue response was significantly greater in cochleae treated with BDNF supraparticles compared to the controls (repeated measures ANOVA, p = 0.003). These data support the clinical potential of this technology particularly as the supraparticles can be loaded with a variety of therapeutic drugs.
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Affiliation(s)
- Andrew K. Wise
- The Bionics Institute, 384–388 Albert Street, East Melbourne, Melbourne, Australia
- The Department of Medical Bionics, University of Melbourne, Melbourne, Australia
- Department of Otolaryngology, University of Melbourne, Melbourne, Australia
- * E-mail:
| | - Justin Tan
- Department of Otolaryngology, University of Melbourne, Melbourne, Australia
| | - Yajun Wang
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, the University of Melbourne, Melbourne, Australia
| | - Frank Caruso
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, the University of Melbourne, Melbourne, Australia
| | - Robert K. Shepherd
- The Bionics Institute, 384–388 Albert Street, East Melbourne, Melbourne, Australia
- The Department of Medical Bionics, University of Melbourne, Melbourne, Australia
- Department of Otolaryngology, University of Melbourne, Melbourne, Australia
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Effects of brain-derived neurotrophic factor (BDNF) on the cochlear nucleus in cats deafened as neonates. Hear Res 2016; 342:134-143. [PMID: 27773647 DOI: 10.1016/j.heares.2016.10.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/23/2016] [Accepted: 10/15/2016] [Indexed: 01/11/2023]
Abstract
Many previous studies have shown significant neurotrophic effects of intracochlear delivery of BDNF in preventing degeneration of cochlear spiral ganglion (SG) neurons after deafness in rodents and our laboratory has shown similar results in developing cats deafened prior to hearing onset. This study examined the morphology of the cochlear nucleus (CN) in a group of neonatally deafened cats from a previous study in which infusion of BDNF elicited a significant improvement in survival of the SG neurons. Five cats were deafened by systemic injections of neomycin sulfate (60 mg/kg, SQ, SID) starting one day after birth, and continuing for 16-18 days until auditory brainstem response (ABR) testing demonstrated profound bilateral hearing loss. The animals were implanted unilaterally at about 1 month of age using custom-designed electrodes with a drug-delivery cannula connected to an osmotic pump. BDNF (94 μg/ml; 0.25 μl/hr) was delivered for 10 weeks. The animals were euthanized and studied at 14-23 weeks of age. Consistent with the neurotrophic effects of BDNF on SG survival, the total CN volume in these animals was significantly larger on the BDNF-treated side than on the contralateral side. However, total CN volume, both ipsi- and contralateral to the implants in these deafened juvenile animals, was markedly smaller than the CN in normal adult animals, reflecting the severe effects of deafness on the central auditory system during development. Data from the individual major CN subdivisions (DCN, Dorsal Cochlear Nucleus; PVCN, Posteroventral Cochlear Nucleus; AVCN, Anteroventral Cochlear Nucleus) also were analyzed. A significant difference was observed between the BDNF-treated and control sides only in the AVCN. Measurements of the cross-sectional areas of spherical cells showed that cells were significantly larger in the AVCN ipsilateral to the implant than on the contralateral side. Further, the numerical density of spherical cells was significantly lower in the AVCN ipsilateral to the implant than on the contralateral side, consistent with the larger AVCN volume observed with BDNF treatment. Together, findings indicate significant neurotrophic effects of intracochlear BDNF infusion on the developing CN.
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Fransson A, Ulfendahl M. Structural changes in the inner ear over time studied in the experimentally deafened guinea pig. J Neurosci Res 2016; 95:869-875. [PMID: 27400677 PMCID: PMC5297876 DOI: 10.1002/jnr.23824] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/03/2016] [Accepted: 06/17/2016] [Indexed: 11/24/2022]
Abstract
Today a cochlear implant (CI) may significantly restore auditory function, even for people with a profound hearing loss. Because the efficacy of a CI is believed to depend mainly on the remaining population of spiral ganglion neurons (SGNs), it is important to understand the timeline of the degenerative process of the auditory neurons following deafness. Guinea pigs were transtympanically deafened with neomycin, verified by recording auditory brainstem responses (ABRs), and then sacrificed at different time points. Loss of SGNs as well as changes in cell body and nuclear volume were estimated. To study the effect of delayed treatment, a group of animals that had been deaf for 12 weeks was implanted with a stimulus electrode mimicking a CI, after which they received a 4‐week treatment with glial cell‐derived neurotrophic factor (GDNF). The electrical responsiveness of the SGNs was measured by recording electrically evoked ABRs. There was a rapid degeneration during the first 7 weeks, shown as a significant reduction of the SGN population. The degenerative process then slowed, and there was no difference in the amount of remaining neurons between weeks 7 and 18. © 2016 The Authors Journal of Neuroscience Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Anette Fransson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Mats Ulfendahl
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Firing frequency and entrainment maintained in primary auditory neurons in the presence of combined BDNF and NT3. Sci Rep 2016; 6:28584. [PMID: 27335179 PMCID: PMC4917828 DOI: 10.1038/srep28584] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 06/07/2016] [Indexed: 12/16/2022] Open
Abstract
Primary auditory neurons rely on neurotrophic factors for development and survival. We previously determined that exposure to brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) alters the activity of hyperpolarization-activated currents (Ih) in this neuronal population. Since potassium channels are sensitive to neurotrophins, and changes in Ih are often accompanied by a shift in voltage-gated potassium currents (IK), this study examined IK with exposure to both BDNF and NT3 and the impact on firing entrainment during high frequency pulse trains. Whole-cell patch-clamp recordings revealed significant changes in action potential latency and duration, but no change in firing adaptation or total outward IK. Dendrotoxin-I (DTX-I), targeting voltage-gated potassium channel subunits KV1.1 and KV1.2, uncovered an increase in the contribution of DTX-I sensitive currents with exposure to neurotrophins. No difference in Phrixotoxin-1 (PaTX-1) sensitive currents, mediated by KV4.2 and KV4.3 subunits, was observed. Further, no difference was seen in firing entrainment. These results show that combined BDNF and NT3 exposure influences the contribution of KV1.1 and KV1.2 to the low voltage-activated potassium current (IKL). Whilst this is accompanied by a shift in spike latency and duration, both firing frequency and entrainment to high frequency pulse trains are preserved.
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Li X, Aleardi A, Wang J, Zhou Y, Andrade R, Hu Z. Differentiation of Spiral Ganglion-Derived Neural Stem Cells into Functional Synaptogenetic Neurons. Stem Cells Dev 2016; 25:803-13. [PMID: 27021700 DOI: 10.1089/scd.2015.0345] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spiral ganglion neurons (SGNs) are usually damaged in sensorineural hearing loss. SGN-derived neural stem cells (NSCs) have been identified and proposed to differentiate into neurons to replace damaged SGNs. However, it remains obscure whether SGN-NSC-derived neurons (ScNs) are electrophysiologically functional and possess the capability to form neural connections. Here, we found that SGN-derived cells demonstrated NSC characteristics and differentiated into SGN-like glutamatergic neurons. Neurotrophins significantly increased neuronal differentiation and neurite length of ScNs. Patch clamp recording revealed that ScNs possessed SGN-like NaV and HCN channels, suggesting electrophysiological function. FM1-43 staining and synaptic protein immunofluorescence showed ScNs possess the ability to form neural connections. Astrocyte-conditioned medium was able to stimulate ScNs to express synaptic proteins. These data suggested that neurotrophins are able to stimulate postnatal SGN-NSCs to differentiate into functional glutamatergic ScNs with the capability to form synaptic connections in vitro.
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Affiliation(s)
- Xiaoyang Li
- 1 Department of Otolaryngology-HNS, Wayne State University School of Medicine , Detroit, Michigan
| | - Alicia Aleardi
- 2 Department of Pharmacology, Wayne State University School of Medicine , Detroit, Michigan
| | - Jue Wang
- 1 Department of Otolaryngology-HNS, Wayne State University School of Medicine , Detroit, Michigan
| | - Yang Zhou
- 1 Department of Otolaryngology-HNS, Wayne State University School of Medicine , Detroit, Michigan
| | - Rodrigo Andrade
- 2 Department of Pharmacology, Wayne State University School of Medicine , Detroit, Michigan
| | - Zhengqing Hu
- 1 Department of Otolaryngology-HNS, Wayne State University School of Medicine , Detroit, Michigan
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Magnetic Beads Enhance Adhesion of NIH 3T3 Fibroblasts: A Proof-of-Principle In Vitro Study for Implant-Mediated Long-Term Drug Delivery to the Inner Ear. PLoS One 2016; 11:e0150057. [PMID: 26918945 PMCID: PMC4769079 DOI: 10.1371/journal.pone.0150057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 02/09/2016] [Indexed: 12/13/2022] Open
Abstract
Introduction Long-term drug delivery to the inner ear may be achieved by functionalizing cochlear implant (CI) electrodes with cells providing neuroprotective factors. However, effective strategies in order to coat implant surfaces with cells need to be developed. Our vision is to make benefit of electromagnetic field attracting forces generated by CI electrodes to bind BDNF-secreting cells that are labelled with magnetic beads (MB) onto the electrode surfaces. Thus, the effect of MB-labelling on cell viability and BDNF production were investigated. Materials and Methods Murine NIH 3T3 fibroblasts—genetically modified to produce BDNF—were labelled with MB. Results Atomic force and bright field microscopy illustrated the internalization of MB by fibroblasts after 24 h of cultivation. Labelling cells with MB did not expose cytotoxic effects on fibroblasts and allowed adhesion on magnetic surfaces with sufficient BDNF release. Discussion Our data demonstrate a novel approach for mediating enhanced long-term adhesion of BDNF-secreting fibroblasts on model electrode surfaces for cell-based drug delivery applications in vitro and in vivo. This therapeutic strategy, once transferred to cells suitable for clinical application, may allow the biological modifications of CI surfaces with cells releasing neurotrophic or other factors of interest.
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Effect of embedded optical fibres on the mechanical properties of cochlear electrode arrays. Med Eng Phys 2016; 38:155-62. [DOI: 10.1016/j.medengphy.2015.11.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 11/11/2015] [Accepted: 11/24/2015] [Indexed: 11/22/2022]
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Pyykkö I, Zou J, Schrott-Fischer A, Glueckert R, Kinnunen P. An Overview of Nanoparticle Based Delivery for Treatment of Inner Ear Disorders. Methods Mol Biol 2016; 1427:363-415. [PMID: 27259938 DOI: 10.1007/978-1-4939-3615-1_21] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nanoparticles offer new possibilities for inner ear treatment as they can carry a variety of drugs, protein, and nucleic acids to inner ear. Nanoparticles are equipped with several functions such as targetability, immuno-transparency, biochemical stability, and ability to be visualized in vivo and in vitro. A group of novel peptides can be attached to the surface of nanoparticles that will enhance the cell entry, endosomal escape, and nuclear targeting. Eight different types of nanoparticles with different payload carrying strategies are available now. The transtympanic delivery of nanoparticles indicates that, depending on the type of nanoparticle, different migration pathways into the inner ear can be employed, and that optimal carriers can be designed according to the intended cargo. The use of nanoparticles as drug/gene carriers is especially attractive in conjunction with cochlear implantation or even as an inclusion in the implant as a drug/gene reservoir.
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Affiliation(s)
- Ilmari Pyykkö
- Department of Otolaryngology, University of Tampere and University Hospital of Tampere, Tampere, 33014, Finland. .,Hearing and Balance Research Unit, Field of Otolaryngology, School of Medicine, University of Tampere, Medisiinarinkatu 3, Tampere, 33520, Finland.
| | - Jing Zou
- BECS, Department of Biomedical Engineering and Computational Science, Aalto University, Aalto, 02150, Espoo, Finland
| | - Annelies Schrott-Fischer
- Department of Otolaryngology, Medical University of Innsbruck, Anichstrasse 35, Innsbruck, 6020, Austria
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Anichstrasse 35, Innsbruck, 6020, Austria
| | - Paavo Kinnunen
- BECS, Department of Biomedical Engineering and Computational Science, Aalto University, Aalto, Finland
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Che X, Wang Z, Liu Y, Sun Y, Liu H. Sustained release of nerve growth factor from highly homogenous cubosomes stabilized by β-casein with enhanced bioactivity and bioavailability. RSC Adv 2016. [DOI: 10.1039/c6ra19887b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The bioactivity of NGF was improved when loaded in β-casein stabilized cubosomes and the cubosomes showed better transport through RWM as compared with free NGF.
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Affiliation(s)
- Xin Che
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang 110016
- P. R. China
| | - Zhenjie Wang
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang 110016
- P. R. China
| | - Yining Liu
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang 110016
- P. R. China
| | - Yanhui Sun
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang 110016
- P. R. China
| | - Hongzhuo Liu
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang 110016
- P. R. China
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Gillespie LN, Richardson RT, Nayagam BA, Wise AK. Treating hearing disorders with cell and gene therapy. J Neural Eng 2015; 11:065001. [PMID: 25420002 DOI: 10.1088/1741-2560/11/6/065001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hearing loss is an increasing problem for a substantial number of people and, with an aging population, the incidence and severity of hearing loss will become more significant over time. There are very few therapies currently available to treat hearing loss, and so the development of new therapeutic strategies for hearing impaired individuals is of paramount importance to address this unmet clinical need. Most forms of hearing loss are progressive in nature and therefore an opportunity exists to develop novel therapeutic approaches to slow or halt hearing loss progression, or even repair or replace lost hearing function. Numerous emerging technologies have potential as therapeutic options. This paper details the potential of cell- and gene-based therapies to provide therapeutic agents to protect sensory and neural cells from various insults known to cause hearing loss; explores the potential of replacing lost sensory and nerve cells using gene and stem cell therapy; and describes the considerations for clinical translation and the challenges that need to be overcome.
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Sameer Mallick A, Qureishi A, Pearson R, O'Donoghue G. Neurotrophins and cochlear implants: a solution to sensorineural deafness? Cochlear Implants Int 2015; 14:158-64. [PMID: 22889496 DOI: 10.1179/1754762812y.0000000013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVES To review current trends for treating sensorineural deafness by enhancing spiral ganglion neuron (SGN) survival using neurotrophins combined with cochlear implants and identify areas for future research and development. METHODS A literature search was undertaken on PubMed and Google scholar using terms: neurotrophins, cochlear implants (CIs), and sensorineural to identify the most recent and significant publications. The abstracts were read to identify relevant papers; these were accessed in full and analysed for this review. RESULTS Neurotrophins have a known role in cochlear development and the maintenance of SGNs. So far experiments using osmotic pumps to deliver neurotrophins have been successful for short-term enhanced survival of SGN's following aminoglycoside ototoxicity in animal models. They have demonstrated the re-sprouting of radial nerve fibres from SGN's towards the source of delivery. In addition electrical stimulation, gene and cell-based therapy have increased SGN survival to varying degrees. DISCUSSION Osmotic pumps carry a high risk of infection therefore CIs coated in a drug containing polymer or hydrogel are a realistic alternative for sustained delivery of neurotrophins. Increased SGN survival combined with neuronal re-growth raises the possibility for CIs to stimulate discrete SGN populations. Unfortunately, the duration of treatment needed for long-term survival still remains unclear and further work is needed. Nevertheless the combination of regenerative medicine to CI technology presents a novel approach to developing CI technology.
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Boisvert I, McMahon CM, Dowell RC, Lyxell B. Long-term asymmetric hearing affects cochlear implantation outcomes differently in adults with pre- and postlingual hearing loss. PLoS One 2015; 10:e0129167. [PMID: 26043227 PMCID: PMC4456415 DOI: 10.1371/journal.pone.0129167] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 05/05/2015] [Indexed: 02/01/2023] Open
Abstract
In many countries, a single cochlear implant is offered as a treatment for a bilateral hearing loss. In cases where there is asymmetry in the amount of sound deprivation between the ears, there is a dilemma in choosing which ear should be implanted. In many clinics, the choice of ear has been guided by an assumption that the reorganisation of the auditory pathways caused by longer duration of deafness in one ear is associated with poorer implantation outcomes for that ear. This assumption, however, is mainly derived from studies of early childhood deafness. This study compared outcomes following implantation of the better or poorer ear in cases of long-term hearing asymmetries. Audiological records of 146 adults with bilateral hearing loss using a single hearing aid were reviewed. The unaided ear had 15 to 72 years of unaided severe to profound hearing loss before unilateral cochlear implantation. 98 received the implant in their long-term sound-deprived ear. A multiple regression analysis was conducted to assess the relative contribution of potential predictors to speech recognition performance after implantation. Duration of bilateral significant hearing loss and the presence of a prelingual hearing loss explained the majority of variance in speech recognition performance following cochlear implantation. For participants with postlingual hearing loss, similar outcomes were obtained by implanting either ear. With prelingual hearing loss, poorer outcomes were obtained when implanting the long-term sound-deprived ear, but the duration of the sound deprivation in the implanted ear did not reliably predict outcomes. Contrary to an apparent clinical consensus, duration of sound deprivation in one ear has limited value in predicting speech recognition outcomes of cochlear implantation in that ear. Outcomes of cochlear implantation are more closely related to the period of time for which the brain is deprived of auditory stimulation from both ears.
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Affiliation(s)
- Isabelle Boisvert
- Department Linguistics, Macquarie University, Sydney, New South Wales, Australia
- HEARing Cooperative Research Centre, Melbourne, Victoria, Australia
- SCIC Cochlear Implant Program - An RIDBC service, Sydney, New South Wales, Australia
- Linnaeus Centre HEAD, The Swedish Institute for Disability Research, Linköping, Sweden
- * E-mail:
| | - Catherine M. McMahon
- Department Linguistics, Macquarie University, Sydney, New South Wales, Australia
- HEARing Cooperative Research Centre, Melbourne, Victoria, Australia
| | - Richard C. Dowell
- HEARing Cooperative Research Centre, Melbourne, Victoria, Australia
- Department of Audiology and Speech Pathology, The University of Melbourne, Melbourne, Victoria, Australia
- Audiology, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Björn Lyxell
- Department of Behavioural Sciences and Learning, Linköping University, Linköping, Sweden
- Linnaeus Centre HEAD, The Swedish Institute for Disability Research, Linköping, Sweden
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Khalin I, Alyautdin R, Kocherga G, Bakar MA. Targeted delivery of brain-derived neurotrophic factor for the treatment of blindness and deafness. Int J Nanomedicine 2015; 10:3245-67. [PMID: 25995632 PMCID: PMC4425321 DOI: 10.2147/ijn.s77480] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Neurodegenerative causes of blindness and deafness possess a major challenge in their clinical management as proper treatment guidelines have not yet been found. Brain-derived neurotrophic factor (BDNF) has been established as a promising therapy against neurodegenerative disorders including hearing and visual loss. Unfortunately, the blood–retinal barrier and blood–cochlear barrier, which have a comparable structure to the blood–brain barrier prevent molecules of larger sizes (such as BDNF) from exiting the circulation and reaching the targeted cells. Anatomical features of the eye and ear allow use of local administration, bypassing histo-hematic barriers. This paper focuses on highlighting a variety of strategies proposed for the local administration of the BDNF, like direct delivery, viral gene therapy, and cell-based therapy, which have been shown to successfully improve development, survival, and function of spiral and retinal ganglion cells. The similarities and controversies for BDNF treatment of posterior eye diseases and inner ear diseases have been analyzed and compared. In this review, we also focus on the possibility of translation of this knowledge into clinical practice. And finally, we suggest that using nanoparticulate drug-delivery systems may substantially contribute to the development of clinically viable techniques for BDNF delivery into the cochlea or posterior eye segment, which, ultimately, can lead to a long-term or permanent rescue of auditory and optic neurons from degeneration.
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Affiliation(s)
- Igor Khalin
- Faculty of Medicine and Defence Health, National Defence University of Malaysia, Kuala Lumpur, Malaysia
| | - Renad Alyautdin
- Scientific Centre for Expertise of Medical Application Products, Moscow, Russia
| | - Ganna Kocherga
- Ophthalmic Microsurgery Department, International Medical Center Oftalmika, Kharkiv, Ukraine
| | - Muhamad Abu Bakar
- Faculty of Medicine and Defence Health, National Defence University of Malaysia, Kuala Lumpur, Malaysia
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Cell-based neurotrophin treatment supports long-term auditory neuron survival in the deaf guinea pig. J Control Release 2015; 198:26-34. [DOI: 10.1016/j.jconrel.2014.11.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 11/25/2014] [Indexed: 12/16/2022]
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Schendzielorz P, Schmitz T, Moseke C, Gbureck U, FrFlich K, Rak K, Groll JR, Hagen R, Radeloff A. Plasma-Assisted Hydrophilization of Cochlear Implant Electrode Array Surfaces Enables Adhesion of Neurotrophin-Secreting Cells. ORL J Otorhinolaryngol Relat Spec 2014; 76:257-65. [DOI: 10.1159/000368321] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 09/09/2014] [Indexed: 11/19/2022]
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Electroacoustic stimulation: now and into the future. BIOMED RESEARCH INTERNATIONAL 2014; 2014:350504. [PMID: 25276779 PMCID: PMC4168031 DOI: 10.1155/2014/350504] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 08/04/2014] [Indexed: 12/22/2022]
Abstract
Cochlear implants have provided hearing to hundreds of thousands of profoundly deaf people around the world. Recently, the eligibility criteria for cochlear implantation have been relaxed to include individuals who have some useful residual hearing. These recipients receive inputs from both electric and acoustic stimulation (EAS). Implant recipients who can combine these hearing modalities demonstrate pronounced benefit in speech perception, listening in background noise, and music appreciation over implant recipients that rely on electrical stimulation alone. The mechanisms bestowing this benefit are unknown, but it is likely that interaction of the electric and acoustic signals in the auditory pathway plays a role. Protection of residual hearing both during and following cochlear implantation is critical for EAS. A number of surgical refinements have been implemented to protect residual hearing, and the development of hearing-protective drug and gene therapies is promising for EAS recipients. This review outlines the current field of EAS, with a focus on interactions that are observed between these modalities in animal models. It also outlines current trends in EAS surgery and gives an overview of the drug and gene therapies that are clinically translatable and may one day provide protection of residual hearing for cochlear implant recipients.
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