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Fogliano C, Motta CM, Avallone B. Salicylate attenuates gentamicin-induced ototoxicity and facilitates the recovery in the basilar papilla of the lizard Podarcis siculus. Neurotoxicology 2022; 93:301-310. [DOI: 10.1016/j.neuro.2022.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/24/2022] [Accepted: 10/24/2022] [Indexed: 11/15/2022]
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2
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He Z, Ding Y, Mu Y, Xu X, Kong W, Chai R, Chen X. Stem Cell-Based Therapies in Hearing Loss. Front Cell Dev Biol 2021; 9:730042. [PMID: 34746126 PMCID: PMC8567027 DOI: 10.3389/fcell.2021.730042] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 10/04/2021] [Indexed: 12/19/2022] Open
Abstract
In recent years, neural stem cell transplantation has received widespread attention as a new treatment method for supplementing specific cells damaged by disease, such as neurodegenerative diseases. A number of studies have proved that the transplantation of neural stem cells in multiple organs has an important therapeutic effect on activation and regeneration of cells, and restore damaged neurons. This article describes the methods for inducing the differentiation of endogenous and exogenous stem cells, the implantation operation and regulation of exogenous stem cells after implanted into the inner ear, and it elaborates the relevant signal pathways of stem cells in the inner ear, as well as the clinical application of various new materials. At present, stem cell therapy still has limitations, but the role of this technology in the treatment of hearing diseases has been widely recognized. With the development of related research, stem cell therapy will play a greater role in the treatment of diseases related to the inner ear.
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Affiliation(s)
- Zuhong He
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yanyan Ding
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yurong Mu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoxiang Xu
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Xiong Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
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Karimi-Boroujeni M, Zahedi-Amiri A, Coombs KM. Embryonic Origins of Virus-Induced Hearing Loss: Overview of Molecular Etiology. Viruses 2021; 13:71. [PMID: 33419104 PMCID: PMC7825458 DOI: 10.3390/v13010071] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 12/19/2022] Open
Abstract
Hearing loss, one of the most prevalent chronic health conditions, affects around half a billion people worldwide, including 34 million children. The World Health Organization estimates that the prevalence of disabling hearing loss will increase to over 900 million people by 2050. Many cases of congenital hearing loss are triggered by viral infections during different stages of pregnancy. However, the molecular mechanisms by which viruses induce hearing loss are not sufficiently explored, especially cases that are of embryonic origins. The present review first describes the cellular and molecular characteristics of the auditory system development at early stages of embryogenesis. These developmental hallmarks, which initiate upon axial specification of the otic placode as the primary root of the inner ear morphogenesis, involve the stage-specific regulation of several molecules and pathways, such as retinoic acid signaling, Sonic hedgehog, and Wnt. Different RNA and DNA viruses contributing to congenital and acquired hearing loss are then discussed in terms of their potential effects on the expression of molecules that control the formation of the auditory and vestibular compartments following otic vesicle differentiation. Among these viruses, cytomegalovirus and herpes simplex virus appear to have the most effect upon initial molecular determinants of inner ear development. Moreover, of the molecules governing the inner ear development at initial stages, SOX2, FGFR3, and CDKN1B are more affected by viruses causing either congenital or acquired hearing loss. Abnormalities in the function or expression of these molecules influence processes like cochlear development and production of inner ear hair and supporting cells. Nevertheless, because most of such virus-host interactions were studied in unrelated tissues, further validations are needed to confirm whether these viruses can mediate the same effects in physiologically relevant models simulating otic vesicle specification and growth.
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Affiliation(s)
- Maryam Karimi-Boroujeni
- School of Rehabilitation Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1H 8M5, Canada;
| | - Ali Zahedi-Amiri
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
- Manitoba Centre for Proteomics and Systems Biology, Winnipeg, MB R3E 3P4, Canada
| | - Kevin M. Coombs
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
- Manitoba Centre for Proteomics and Systems Biology, Winnipeg, MB R3E 3P4, Canada
- Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
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Farhadi M, Salem MM, Asghari A, Daneshi A, Mirsalehi M, Mahmoudian S. Impact of Acamprosate on Chronic Tinnitus: A Randomized-Controlled Trial. Ann Otol Rhinol Laryngol 2020; 129:1110-1119. [PMID: 32500717 DOI: 10.1177/0003489420930773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Tinnitus is a common and distressing otologic symptom, with various probable pathophysiologic mechanisms, such as an imbalance between excitatory and inhibitory mechanisms. Acamprosate, generally used to treat alcoholism, is a glutaminergic antagonist and GABA agonist suggested for treating tinnitus. Thus, we aimed to evaluate the efficacy and safety of acamprosate in the treatment of tinnitus. METHODS The current randomized-controlled trial study included 20 subjects with chronic tinnitus. After performing psycho-acoustic, psychometric and electrophysiological evaluations, all studied tinnitus subjects were randomly divided into two groups of acamprosate and placebo. The first group received oral acamprosate (two tablets of 333 mg/d, three times a day), whereas the second group was given placebo treatment (two tablets, three times a day). After the first 30 days, all evaluations were repeated for the studied groups just in the same manner before the study. Subsequently, the final results of each evaluation were compared together with the baseline values. RESULTS Nine studied subjects randomly received acamprosate, whereas eleven others received a placebo. There was no significant improvement in the psycho-acoustic tests, except a decrease was observed in the pitch match of tinnitus (P = .039). For those subjects who were receiving acamprosate, a significant reduction was observed in tinnitus handicap inventory (P = .006), tinnitus questionnaire scores (P = .007), and the visual analog scores (P = .007) compared to the placebo group. There was a significant reduction in Action Potential latency (P = .048) as well as an increase in the amplitude of distortion product otoacoustic emissions at 4 kHz (P = .048). CONCLUSIONS The study results indicated a subjective relief of tinnitus as well as some degree of the electrophysiological improvement at the level of the cochlear and the distal portion of the auditory nerve among the subjects who received the acamprosate. CLINICAL TRIAL REGISTRATION CODE IRCT2013121115751N1.
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Affiliation(s)
- Mohammad Farhadi
- ENT and Head & Neck Research Center and Department, the Five Senses Health Institute, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Mahdi Salem
- ENT and Head & Neck Research Center and Department, the Five Senses Health Institute, Iran University of Medical Sciences, Tehran, Iran
| | - Alimohamad Asghari
- Skull Base Research Center, Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Ahmad Daneshi
- ENT and Head & Neck Research Center and Department, the Five Senses Health Institute, Iran University of Medical Sciences, Tehran, Iran
| | - Marjan Mirsalehi
- ENT and Head & Neck Research Center and Department, the Five Senses Health Institute, Iran University of Medical Sciences, Tehran, Iran
| | - Saeid Mahmoudian
- ENT and Head & Neck Research Center and Department, the Five Senses Health Institute, Iran University of Medical Sciences, Tehran, Iran
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5
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Ghanavatinejad F, Fard Tabrizi ZP, Omidghaemi S, Sharifi E, Møller SG, Jami MS. Protein biomarkers of neural system. J Otol 2019; 14:77-88. [PMID: 31467504 PMCID: PMC6712353 DOI: 10.1016/j.joto.2019.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/14/2019] [Accepted: 03/20/2019] [Indexed: 11/30/2022] Open
Abstract
The utilization of biomarkers for in vivo and in vitro research is growing rapidly. This is mainly due to the enormous potential of biomarkers in evaluating molecular and cellular abnormalities in cell models and in tissue, and evaluating drug responses and the effectiveness of therapeutic intervention strategies. An important way to analyze the development of the human body is to assess molecular markers in embryonic specialized cells, which include the ectoderm, mesoderm, and endoderm. Neuronal development is controlled through the gene networks in the neural crest and neural tube, both components of the ectoderm. The neural crest differentiates into several different tissues including, but not limited to, the peripheral nervous system, enteric nervous system, melanocyte, and the dental pulp. The neural tube eventually converts to the central nervous system. This review provides an overview of the differentiation of the ectoderm to a fully functioning nervous system, focusing on molecular biomarkers that emerge at each stage of the cellular specialization from multipotent stem cells to completely differentiated cells. Particularly, the otic placode is the origin of most of the inner ear cell types such as neurons, sensory hair cells, and supporting cells. During the development, different auditory cell types can be distinguished by the expression of the neurogenin differentiation factor1 (Neuro D1), Brn3a, and transcription factor GATA3. However, the mature auditory neurons express other markers including βIII tubulin, the vesicular glutamate transporter (VGLUT1), the tyrosine receptor kinase B and C (Trk B, C), BDNF, neurotrophin 3 (NT3), Calretinin, etc.
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Affiliation(s)
- Fatemeh Ghanavatinejad
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Science, Shahrekord, Iran
| | - Zahra Pourteymour Fard Tabrizi
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Science, Shahrekord, Iran
| | - Shadi Omidghaemi
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Science, Shahrekord, Iran
| | - Esmaeel Sharifi
- Department of Tissue Engineering and Biomaterials, School of Advanced Medical Sciences and Technologies, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Simon Geir Møller
- Department of Biological Sciences, St John's University, New York, NY, USA
- The Norwegian Centre for Movement Disorders, Stavanger University Hospital, Norway
| | - Mohammad-Saeid Jami
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Science, Shahrekord, Iran
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, CA, 90095, USA
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Niknazar S, Abbaszadeh HA, Peyvandi H, Rezaei O, Forooghirad H, Khoshsirat S, Peyvandi AA. Protective effect of [Pyr1]-apelin-13 on oxidative stress-induced apoptosis in hair cell-like cells derived from bone marrow mesenchymal stem cells. Eur J Pharmacol 2019; 853:25-32. [PMID: 30876980 DOI: 10.1016/j.ejphar.2019.03.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 03/06/2019] [Accepted: 03/11/2019] [Indexed: 12/19/2022]
Abstract
Oxidative stress plays an important role in auditory dysfunction. Exogenous cell therapy has brought new hopes for repairing mammalian inner ear hair cells. However, poor cell viability of transplanted cells under oxidative stress conditions has limited their therapeutic potential. The adipocytokine apelin-13 was isolated from a bovine stomach. Apelin-13 might protect oxidative stress-induced hair cell damage was raised considering other oxidative stress-induced injury, including brain ischemia-induced cell death. Therefore, we evaluated the protective effects of apelin- 13 on the damage induced by hydrogen peroxide (H2O2) to the hair cells-derived from bone marrow mesenchymal stem cells (BMSCs) in vitro. Stem cells were differentiated into hair cell- like cells with B27, FGF, EGF and IGF-1. Expression of neuron specific markers including β tubulin III, Nestin, MAP2, Neurofilament 68 and GFAP was tested by flow cytometry. As well, inner ear hair cell markers such as Myosin VIIA, Sox2 and TrkB expression were assayed by immunocytochemistry (ICC) method. We designed an in vitro model of oxidative stress by exposing hair cell- like cells to H2O2. Protein expression levels of caspase-3, Bax and Bcl-2 were detected by western blot. Apoptotic cells were also detected by acridin-orange staining and TUNEL assay. Protein expression of caspase-3 and Bax/Bcl-2 ratio was significantly lower in the apelin-13-pretreated group than only H2O2 treated group. In addition, apoptotic cells were significantly decreased in the apelin-13+H2O2 co-treated cells compared to the H2O2-treated group. Treating hair cells-like cells with apelin13 increases their survival against oxidative stress damage by inhibition of apoptosis signaling pathway.
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Affiliation(s)
- Somayeh Niknazar
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Hojjat-Allah Abbaszadeh
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Anatomical Sciences and Biology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hassan Peyvandi
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Omidvar Rezaei
- Skull Base Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hosna Forooghirad
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shahrokh Khoshsirat
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Ali Asghar Peyvandi
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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7
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Abstract
OBJECTIVE Effective management of patients diagnosed with ototoxicity is needed to reduce hearing and balance damage which affects communication and life quality. Despite widespread recommendations to monitor and manage ototoxicity in an early and effective manner, there is limited evidence to support the actual implementation of these recommendations for affected patient groups in healthcare services across the UK with limited publications available. In this study, an online questionnaire analysed the current practice of ototoxicity management and patient pathways across the UK once the diagnosis of ototoxicity was confirmed, targeting Audiologists, ENTs/AVPs and GPs. DESIGN Qualitative Survey Study. STUDY SAMPLE A randomised sample of hearing services in the UK, including audiology departments; GP practices and local health settings were targeted with a total of 134 completed surveys. RESULTS About 72% reported the absence of ototoxicity management protocols within their centre. Results depicted great inconsistency and variation across the UK in ototoxicity management services provided, treatment modification, monitoring and referral pathways. CONCLUSION Developing and advocating national guidelines are intended not only to inform clinical decision making but to provide minimum standards of care in ototoxicity management and offer greater awareness and education to improve patients' quality of life.
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Affiliation(s)
- Devina Maru
- a UCL Ear Institute , University College London , London , UK
| | - Ghada-Al Malky
- a UCL Ear Institute , University College London , London , UK
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8
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Peyvandi AA, Roozbahany NA, Peyvandi H, Abbaszadeh HA, Majdinasab N, Faridan M, Niknazar S. Critical role of SDF-1/CXCR4 signaling pathway in stem cell homing in the deafened rat cochlea after acoustic trauma. Neural Regen Res 2018; 13:154-160. [PMID: 29451220 PMCID: PMC5840981 DOI: 10.4103/1673-5374.224382] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Previous animal studies have shown that stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor-4 (CXCR4) signaling pathway plays an important role in the targeted migration of bone marrow-derived mesenchymal stem cells (BMSCs) to the injured area. In the present study, we aimed to investigate the potential role of chemotactic SDF-1/CXCR4 signaling pathway in the homing of transplanted BMSCs to the injured cochlea after noise-induced hearing loss (NIHL) in a rat model. White noise exposure (110 dB) paradigm was used for hearing loss induction in male rats for 6 hours in 5 days. Distortion-product otoacoustic emission (DPOAE) responses were recorded before the experiment and post noise exposure. Hoechst 33342-labeled BMSCs and CXCR4 antagonist (AMD3100)-treated BMSCs were injected into the rat cochlea through the round window. SDF-1 protein expression in the cochlear tissue was assayed using western blot assay. The number of labeled BMSCs reaching the endolymph was determined after 24 hours. SDF-1 was significantly increased in the cochlear tissue of rats in the noise exposure group than in the control group. The number of Hoechst 33342-labeled BMSCs reaching the endolymph of the cochlea was significantly smaller in the AMD3100-treated BMSCs group than in the normal BMSCs group. Our present findings suggest that the SDF-1/CXCR4 signaling pathway has a critical role in BMSCs migration to the injured cochlea in a rat model of noise-induced hearing loss.
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Affiliation(s)
- Ali Asghar Peyvandi
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Navid Ahmady Roozbahany
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; G. Raymond Chang School, Ryerson University, Toronto, Canada
| | - Hassan Peyvandi
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Yale University, New Haven, CT, USA
| | - Hojjat-Allah Abbaszadeh
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences; Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Niloofar Majdinasab
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Faridan
- Department of Occupational Health Engineering, School of Health, Loorestan University of Medical Sciences, Khorramabad, Iran
| | - Somayeh Niknazar
- Hearing Disorders Research Center, Loghman Hakim Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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9
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Efficacy of Human Adipose Tissue-Derived Stem Cells on Neonatal Bilirubin Encephalopathy in Rats. Neurotox Res 2016; 29:514-24. [PMID: 26818600 DOI: 10.1007/s12640-016-9599-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 12/04/2015] [Accepted: 12/28/2015] [Indexed: 10/22/2022]
Abstract
Kernicterus is a neurological syndrome associated with indirect bilirubin accumulation and damages to the basal ganglia, cerebellum and brain stem nuclei particularly the cochlear nucleus. To mimic haemolysis in a rat model such that it was similar to what is observed in a preterm human, we injected phenylhydrazine in 7-day-old rats to induce haemolysis and then infused sulfisoxazole into the same rats at day 9 to block bilirubin binding sites in the albumin. We have investigated the effectiveness of human adiposity-derived stem cells as a therapeutic paradigm for perinatal neuronal repair in a kernicterus animal model. The level of total bilirubin, indirect bilirubin, brain bilirubin and brain iron was significantly increased in the modelling group. There was a significant decreased in all severity levels of the auditory brainstem response test in the two modelling group. Akinesia, bradykinesia and slip were significantly declined in the experience group. Apoptosis in basal ganglia and cerebellum were significantly decreased in the stem cell-treated group in comparison to the vehicle group. All severity levels of the auditory brainstem response tests were significantly decreased in 2-month-old rats. Transplantation results in the substantial alleviation of walking impairment, apoptosis and auditory dysfunction. This study provides important information for the development of therapeutic strategies using human adiposity-derived stem cells in prenatal brain damage to reduce potential sensori motor deficit.
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10
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Petersen L, Rogers C. Aminoglycoside-induced hearing deficits – a review of cochlear ototoxicity. S Afr Fam Pract (2004) 2015. [DOI: 10.1080/20786190.2014.1002220] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Potential roles of stem cells in the management of sensorineural hearing loss. The Journal of Laryngology & Otology 2012; 126:653-7. [PMID: 22624825 DOI: 10.1017/s0022215112000850] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND In the management of sensorineural hearing loss, effective therapy for degenerated hair cells, third order neurons, ganglions, dendrites and synaptic areas of the vestibulo-cochleo-cerebral pathway remains an enigma. Transplantation of stem and progenitor cells appears to be an emerging potential solution, and is the focus of this review. AIM To review recent developments in the management of sensorineural hearing loss in the field of stem cell research. MATERIALS AND METHOD A systematic review of the English language literature included all experimental and non-experimental studies with a Jadad score of three or more, published between 2000 and 2010 and included in the following databases: Cochrane Library Ear, Nose and Throat Disorders; Medline; Google Scholar; Hinari; and the Online Library of Toronto University. RESULTS Of the 455 and 29 600 articles identified from Medline and Google Scholar, respectively, 48 met the inclusion criteria. These were independently reviewed and jointly analysed. CONCLUSION Although there is not yet any evidence from successful human studies, stem cell and 'alternative stem cell' technology seems to represent the future of sensorineural hearing loss management.
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Devarajan K, Staecker H, Detamore MS. A review of gene delivery and stem cell based therapies for regenerating inner ear hair cells. J Funct Biomater 2011; 2:249-70. [PMID: 24956306 PMCID: PMC4030941 DOI: 10.3390/jfb2030249] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 08/31/2011] [Accepted: 09/05/2011] [Indexed: 12/13/2022] Open
Abstract
Sensory neural hearing loss and vestibular dysfunction have become the most common forms of sensory defects, affecting millions of people worldwide. Developing effective therapies to restore hearing loss is challenging, owing to the limited regenerative capacity of the inner ear hair cells. With recent advances in understanding the developmental biology of mammalian and non-mammalian hair cells a variety of strategies have emerged to restore lost hair cells are being developed. Two predominant strategies have developed to restore hair cells: transfer of genes responsible for hair cell genesis and replacement of missing cells via transfer of stem cells. In this review article, we evaluate the use of several genes involved in hair cell regeneration, the advantages and disadvantages of the different viral vectors employed in inner ear gene delivery and the insights gained from the use of embryonic, adult and induced pluripotent stem cells in generating inner ear hair cells. Understanding the role of genes, vectors and stem cells in therapeutic strategies led us to explore potential solutions to overcome the limitations associated with their use in hair cell regeneration.
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Affiliation(s)
| | - Hinrich Staecker
- Department of Otolaryngology Head and Neck Surgery, University of Kansas School of Medicine, Kansas City, KS 66160, USA.
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13
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Carricondo F, Iglesias MC, Rodríguez F, Poch-Broto J, Gil-Loyzaga P. In vitro long-term development of cultured inner ear stem cells of newborn rat. Cell Tissue Res 2010; 342:13-9. [PMID: 20838813 DOI: 10.1007/s00441-010-1039-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 08/16/2010] [Indexed: 11/30/2022]
Abstract
The adult mammalian auditory receptor lacks any ability to repair and/or regenerate after injury. However, the late developing cochlea still contains some stem-cell-like elements that might be used to regenerate damaged neurons and/or cells of the organ of Corti. Before their use in any application, stem cell numbers need to be amplified because they are usually rare in late developing and adult tissues. The numerous re-explant cultures required for the progressive amplification process can result in a spontaneous differentiation process. This aspect has been implicated in the tumorigenicity of stem cells when transplanted into a tissue. The aim of this study has been to determine whether cochlear stem cells can proliferate and differentiate spontaneously in long-term cultures without the addition of any factor that might influence these processes. Cochlear stem cells, which express nestin protein, were cultured in monolayers and fed with DMEM containing 5% FBS. They quickly organized themselves into typical spheres exhibiting a high proliferation rate, self-renewal property, and differentiation ability. Secondary cultures of these stem cell spheres spontaneously differentiated into neuroectodermal-like cells. The expression of nestin, glial-fibrillary-acidic protein, vimentin, and neurofilaments was evaluated to identify early differentiation. Nestin expression appeared in primary and secondary cultures. Other markers were also identified in differentiating cells. Further research might demonstrate the spontaneous differentiation of cochlear stem cells and their teratogenic probability when they are used for transplantation.
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Affiliation(s)
- Francisco Carricondo
- Department of Ophtalmology and Otorhinolaryngology, Faculty of Medicine, Complutense University of Madrid, Apartado de Correos 60.075, 28080 Madrid, Spain
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14
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Abstract
Sensory hair cells of the inner ear are responsible for translating auditory or vestibular stimuli into electrical energy that can be perceived by the nervous system. Although hair cells are exquisitely mechanically sensitive, they can be easily damaged by excessive stimulation by ototoxic drugs and by the effects of aging. In mammals, auditory hair cells are never replaced, such that cumulative damage to the ear causes progressive and permanent deafness. In contrast, non-mammalian vertebrates are capable of replacing lost hair cells, which has led to efforts to understand the molecular and cellular basis of regenerative responses in different vertebrate species. In this review, we describe recent progress in understanding the limits to hair cell regeneration in mammals and discuss the obstacles that currently exist for therapeutic approaches to hair cell replacement.
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Affiliation(s)
- Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, BCM 295, 1 Baylor Plaza, Houston, TX 77030, USA.
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15
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Warchol ME, Montcouquiol M. Maintained expression of the planar cell polarity molecule Vangl2 and reformation of hair cell orientation in the regenerating inner ear. J Assoc Res Otolaryngol 2010; 11:395-406. [PMID: 20177731 DOI: 10.1007/s10162-010-0209-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 01/18/2010] [Indexed: 12/27/2022] Open
Abstract
The avian inner ear possesses a remarkable ability to regenerate sensory hair cells after ototoxic injury. Regenerated hair cells possess phenotypes and innervation that are similar to those found in the undamaged ear, but little is known about the signaling pathways that guide hair cell differentiation during the regenerative process. The aim of the present study was to examine the factors that specify the orientation of hair cell stereocilia bundles during regeneration. Using organ cultures of the chick utricle, we show that hair cells are properly oriented after having regenerated entirely in vitro and that orientation is not affected by surgical removal of the striolar reversal zone. These results suggest that the orientation of regenerating stereocilia is not guided by the release of a diffusible morphogen from the striolar reversal zone but is specified locally within the regenerating sensory organ. In order to determine the nature of the reorientation cues, we examined the expression patterns of the core planar cell polarity molecule Vangl2 in the normal and regenerating utricle. We found that Vangl2 is asymmetrically expressed on cells within the sensory epithelium and that this expression pattern is maintained after ototoxic injury and throughout regeneration. Notably, treatment with a small molecule inhibitor of c-Jun-N-terminal kinase disrupted the orientation of regenerated hair cells. Both of these results are consistent with the hypothesis that noncanonical Wnt signaling guides hair cell orientation during regeneration.
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Affiliation(s)
- Mark E Warchol
- Fay and Carl Simons Center for the Biology of Hearing and Deafness, Department of Otolaryngology, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO 63110, USA.
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16
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Russo G, Calzi D, Gioglio L, Botta L, Polimeni M, Zucca G, Martini M, Contini D, Fesce R, Rossi M, Prigioni I. Analysis of pre- and postsynaptic activity in the frog semicircular canal following ototoxic insult: differential recovery of background and evoked afferent activity. Neuroscience 2009; 163:1327-39. [DOI: 10.1016/j.neuroscience.2009.07.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Revised: 07/13/2009] [Accepted: 07/13/2009] [Indexed: 11/29/2022]
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17
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Hendricks JL, Chikar JA, Crumling MA, Raphael Y, Martin DC. Localized cell and drug delivery for auditory prostheses. Hear Res 2008; 242:117-31. [PMID: 18573323 DOI: 10.1016/j.heares.2008.06.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 05/09/2008] [Accepted: 06/02/2008] [Indexed: 12/20/2022]
Abstract
Localized cell and drug delivery to the cochlea and central auditory pathway can improve the safety and performance of implanted auditory prostheses (APs). While generally successful, these devices have a number of limitations and adverse effects including limited tonal and dynamic ranges, channel interactions, unwanted stimulation of non-auditory nerves, immune rejection, and infections including meningitis. Many of these limitations are associated with the tissue reactions to implanted auditory prosthetic devices and the gradual degeneration of the auditory system following deafness. Strategies to reduce the insertion trauma, degeneration of target neurons, fibrous and bony tissue encapsulation, and immune activation can improve the viability of tissue required for AP function as well as improve the resolution of stimulation for reduced channel interaction and improved place-pitch and level discrimination. Many pharmaceutical compounds have been identified that promote the viability of auditory tissue and prevent inflammation and infection. Cell delivery and gene therapy have provided promising results for treating hearing loss and reversing degeneration. Currently, many clinical and experimental methods can produce extremely localized and sustained drug delivery to address AP limitations. These methods provide better control over drug concentrations while eliminating the adverse effects of systemic delivery. Many of these drug delivery techniques can be integrated into modern auditory prosthetic devices to optimize the tissue response to the implanted device and reduce the risk of infection or rejection. Together, these methods and pharmaceutical agents can be used to optimize the tissue-device interface for improved AP safety and effectiveness.
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Affiliation(s)
- Jeffrey L Hendricks
- Department of Biomedical Engineering, The University of Michigan, 1107 Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109-2099, USA.
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18
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19
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Hua Y, Xiao–wei C, Zhi–qiang G. Recent progresses in stem cell research and hearing restoration. J Otol 2008. [DOI: 10.1016/s1672-2930(08)50001-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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20
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Seelman KD, Palmer CV, Ortmann A, Mormer E, Guthrie O, Miele J, Brabyn J. Quality-of-life technology for vision and hearing loss. IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE : THE QUARTERLY MAGAZINE OF THE ENGINEERING IN MEDICINE & BIOLOGY SOCIETY 2008; 27:40-55. [PMID: 18463020 DOI: 10.1109/emb.2007.907393] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Katherine D Seelman
- Department of Communication Science and Disorders, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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21
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Lang H, Schulte BA, Goddard JC, Hedrick M, Schulte JB, Wei L, Schmiedt RA. Transplantation of mouse embryonic stem cells into the cochlea of an auditory-neuropathy animal model: effects of timing after injury. J Assoc Res Otolaryngol 2008; 9:225-40. [PMID: 18449604 DOI: 10.1007/s10162-008-0119-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2007] [Accepted: 03/06/2008] [Indexed: 12/18/2022] Open
Abstract
Application of ouabain to the round window membrane of the gerbil selectively induces the death of most spiral ganglion neurons and thus provides an excellent model for investigating the survival and differentiation of embryonic stem cells (ESCs) introduced into the inner ear. In this study, mouse ESCs were pretreated with a neural-induction protocol and transplanted into Rosenthal's canal (RC), perilymph, or endolymph of Mongolian gerbils either 1-3 days (early post-injury transplant group) or 7 days or longer (late post-injury transplant group) after ouabain injury. Overall, ESC survival in RC and perilymphatic spaces was significantly greater in the early post-injury microenvironment as compared to the later post-injury condition. Viable clusters of ESCs within RC and perilymphatic spaces appeared to be associated with neovascularization in the early post-injury group. A small number of ESCs transplanted within RC stained for mature neuronal or glial cell markers. ESCs introduced into perilymph survived in several locations, but most differentiated into glia-like cells. ESCs transplanted into endolymph survived poorly if at all. These experiments demonstrate that there is an optimal time window for engraftment and survival of ESCs that occurs in the early post-injury period.
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Affiliation(s)
- Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 165 Ashley Avenue, P.O. Box 250908, Charleston, SC 29425, USA.
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22
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Lu Z, Corwin JT. The influence of glycogen synthase kinase 3 in limiting cell addition in the mammalian ear. Dev Neurobiol 2008; 68:1059-75. [DOI: 10.1002/dneu.20635] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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23
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Oesterle EC, Campbell S, Taylor RR, Forge A, Hume CR. Sox2 and JAGGED1 expression in normal and drug-damaged adult mouse inner ear. J Assoc Res Otolaryngol 2007; 9:65-89. [PMID: 18157569 DOI: 10.1007/s10162-007-0106-7] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Accepted: 10/25/2007] [Indexed: 12/20/2022] Open
Abstract
Inner ear hair cells detect environmental signals associated with hearing, balance, and body orientation. In humans and other mammals, significant hair cell loss leads to irreversible hearing and balance deficits, whereas hair cell loss in nonmammalian vertebrates is repaired by the spontaneous generation of replacement hair cells. Research in mammalian hair cell regeneration is hampered by the lack of in vivo damage models for the adult mouse inner ear and the paucity of cell-type-specific markers for non-sensory cells within the sensory receptor epithelia. The present study delineates a protocol to drug damage the adult mouse auditory epithelium (organ of Corti) in situ and uses this protocol to investigate Sox2 and Jagged1 expression in damaged inner ear sensory epithelia. In other tissues, the transcription factor Sox2 and a ligand member of the Notch signaling pathway, Jagged1, are involved in regenerative processes. Both are involved in early inner ear development and are expressed in developing support cells, but little is known about their expressions in the adult. We describe a nonsurgical technique for inducing hair cell damage in adult mouse organ of Corti by a single high-dose injection of the aminoglycoside kanamycin followed by a single injection of the loop diuretic furosemide. This drug combination causes the rapid death of outer hair cells throughout the cochlea. Using immunocytochemical techniques, Sox2 is shown to be expressed specifically in support cells in normal adult mouse inner ear and is not affected by drug damage. Sox2 is absent from auditory hair cells, but is expressed in a subset of vestibular hair cells. Double-labeling experiments with Sox2 and calbindin suggest Sox2-positive hair cells are Type II. Jagged1 is also expressed in support cells in the adult ear and is not affected by drug damage. Sox2 and Jagged1 may be involved in the maintenance of support cells in adult mouse inner ear.
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Affiliation(s)
- Elizabeth C Oesterle
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, CHDD CD176, Box 357923, Seattle, WA 98195-7923, USA.
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Haque A, Zakir M, Dickman JD. Recovery of gaze stability during vestibular regeneration. J Neurophysiol 2007; 99:853-65. [PMID: 18045999 DOI: 10.1152/jn.01038.2007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Many motion related behaviors, such as gaze stabilization, balance, orientation, and navigation largely depend on a properly functioning vestibular system. After vestibular insult, many of these responses are compromised but can return during the regeneration of vestibular receptors and afferents as is known to occur in birds, reptiles, and amphibians. Here we characterize gaze stability in pigeons to rotational motion during regeneration after complete bilateral vestibular loss via an ototoxic antibiotic. Immediate postlesion effects included severe head oscillations, postural ataxia, and total lack of gaze control. We found that these abnormal behaviors gradually subsided, and gaze stability slowly returned to normal function according to a temporal sequence that lasted several months. We also found that the dynamic recovery of gaze function during regeneration was not homogeneous for all types of motion. Instead high-frequency motion stability was first achieved, followed much later by slow movement stability. In addition, we found that initial gaze stability was established using almost exclusive head-response components with little eye-movement contribution. However, that trend reversed as recovery progressed so that when gaze stability was complete, the eye component had increased and the head response had decreased to levels significantly different from that observed in normal birds. This was true even though the head-fixed VOR response recovered normally. Recovery of gaze stability coincided well with the three stage temporal sequence of morphologic regeneration previously described by our laboratory.
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Affiliation(s)
- Asim Haque
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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25
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26
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Nagy I, Fuchs S, Monge A, Huber A, Bodmer D. [Transplantation of neural stem cells into the cochlea]. HNO 2007; 55:862-70. [PMID: 17487462 DOI: 10.1007/s00106-007-1538-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Stem cell therapy is especially interesting for inner ear related diseases, since the hair cells are very sensitive and do not regenerate. Hair cell loss is therefore irreversible and is accompanied by hearing loss. In the last few years, different research groups have transplanted stem cells into the inner ear with promising results. In the presented study, our aim was to gain insight into how neuronal stem cells behave when they are transplanted, both in vitro and in vivo, into a damaged inner ear. METHODS Neuronal stem cells from E9.5 day old mouse embryos were collected and infected with an adenoviral vector encoding green fluorescent protein (GFP). GFP+ cells were then transplanted into a damaged organ of Corti in vitro or into a damaged mouse inner ear in vivo. RESULTS We were able to detect GFP+ cells close to the organ of Corti in vitro and in the organ of Corti in vivo. The GFP+ cells do not seem to be randomly distributed in either the in vitro or in vivo situation. Most interestingly, GFP+ cells could be detected close to places where hair cells had been lost in vivo. CONCLUSION Neuronal stem cells are interesting candidates to replace lost hair cells. However, a great deal of research is still needed before they can enter clinical trials.
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Affiliation(s)
- I Nagy
- Klinik für Ohren-, Nasen-, Hals- und Gesichtschirurgie, Universitätsspital Zürich, Frauenklinikstr. 24, 8091, Zürich, Schweiz
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Sekiya T, Kojima K, Matsumoto M, Holley MC, Ito J. Rebuilding lost hearing using cell transplantation. Neurosurgery 2007; 60:417-33; discussion 433. [PMID: 17327786 DOI: 10.1227/01.neu.0000249189.46033.42] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE The peripheral auditory nervous system (cochlea and auditory nerve) has a complex anatomy, and it has traditionally been thought that once the sensorineural structures are damaged, restoration of hearing is impossible. In the past decade, however, the potential to restore lost hearing has been intensively investigated using molecular and cell biological techniques, and we can now part with such a pessimistic view. In this review, we examine an important field in hearing restoration research: cell transplantation. METHODS Most efforts in this field have been directed to the replacement of hair cells by transplantation to the cochlea. Here, we focus on transplantation to the auditory nerve, from the side of the cerebellopontine angle rather than the cochlea. RESULTS Delivery of cells to the cochlea is potentially damaging, and nerve cells transplanted distally to the Schwann-glial transitional zone (cochlear side) may become inhibited when they reach the transitional zone. The auditory nerve is probably the most suitable route for cell transplantation. CONCLUSION The auditory nerve occupies an important position not only in neurosurgery but also in various diseases in other disciplines, and several lines of recent evidence indicate that it is a key target for hearing restoration. It is familiar to most neurosurgeons, and the recent advances in the molecular and cell biology of inner-ear development are of direct importance to neurorestorative medicine. In this article, we review the anatomy, development, and molecular biology of the auditory nerve and cochlea, with emphasis on the advances in cell transplantation.
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Affiliation(s)
- Tetsuji Sekiya
- Department of Otolaryngology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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28
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Lou X, Zhang Y, Yuan C. Multipotent stem cells from the young rat inner ear. Neurosci Lett 2007; 416:28-33. [PMID: 17350759 DOI: 10.1016/j.neulet.2006.12.061] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 12/01/2006] [Accepted: 12/16/2006] [Indexed: 01/01/2023]
Abstract
The terminal mitosis of hair cells (HCs) and supporting cells (SCs) in mammalian cochlea occurred during middle embryonic development. Most hearing loss results from the incapacity of the cochlear sensory epithelium to replace lost hear cells. Deafness due to hair cells loss is normally irreversible. The present study showed that cells acutely dissociated from the cochlea of young rat, cultured with EGF and FGF2, developed into otospheres that showed expression of nestin and incorporation of 5'-Bromo-2-deoxyuridine (BrdU). The subcultured otospheres maintained for up to 10 passages. In addition, the cochlea sphere-derivatives contributed to a variety of cell types. They were found to differentiate to neuron, glia, hair cell and supporting cell phenotypes. The results suggest that the young rat inner ear cells have self-renewal capability and multipotent differentiation potential. This work raises the possibility that inner ear cells in the early post-natal rat have the character of pluripotent stem cells and might be a source for cell replacement therapy in the inner ear.
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Affiliation(s)
- Xiangxin Lou
- School of Life Science, East China Normal University, Shanghai, PR China.
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Laine H, Doetzlhofer A, Mantela J, Ylikoski J, Laiho M, Roussel MF, Segil N, Pirvola U. p19(Ink4d) and p21(Cip1) collaborate to maintain the postmitotic state of auditory hair cells, their codeletion leading to DNA damage and p53-mediated apoptosis. J Neurosci 2007; 27:1434-44. [PMID: 17287518 PMCID: PMC6673588 DOI: 10.1523/jneurosci.4956-06.2007] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 12/22/2006] [Accepted: 12/22/2006] [Indexed: 11/21/2022] Open
Abstract
Sensory hair cells of the auditory organ are generated during embryogenesis and remain postmitotic throughout life. Previous work has shown that inactivation of the cyclin-dependent kinase inhibitor (CKI) p19(Ink4d) leads to progressive hearing loss attributable to inappropriate DNA replication and subsequent apoptosis of hair cells. Here we show the synergistic action of another CKI, p21(Cip1), on cell cycle reactivation. The codeletion of p19(Ink4d) and p21(Cip1) triggered profuse S-phase entry of auditory hair cells during a restricted period in early postnatal life, leading to the transient appearance of supernumerary hair cells. In addition, we show that aberrant cell cycle reentry leads to activation of a DNA damage response pathway in these cells, followed by p53-mediated apoptosis. The majority of hair cells were absent in adult cochleas. These data, together with the demonstration of changing expression patterns of multiple CKIs in auditory hair cells during the stages of early postnatal maturation, show that the maintenance of the postmitotic state is an active, tissue-specific process, cooperatively regulated by several CKIs, and is critical for the lifelong survival of these sensory cells.
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Affiliation(s)
| | - Angelika Doetzlhofer
- Gonda Department of Cell and Molecular Biology, House Ear Institute, Los Angeles, California 90057, and
| | | | | | - Marikki Laiho
- Molecular Cancer Biology Program, Biomedicum Helsinki, University of Helsinki, 00014 Helsinki, Finland
| | - Martine F. Roussel
- Department of Tumor Biology and Genetics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Neil Segil
- Gonda Department of Cell and Molecular Biology, House Ear Institute, Los Angeles, California 90057, and
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Abstract
The sensory epithelia of the inner ear contain mechanosensory hair cells and non-sensory supporting cells. Both classes of cell are heterogeneous, with phenotypes varying both between and within epithelia. The specification of individual cells as distinct types of hair cell or supporting cell is regulated through intra- and extracellular signalling pathways that have been poorly understood. However, new methodologies have resulted in significant steps forward in our understanding of the molecular pathways that direct cells towards these cell fates.
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Affiliation(s)
- Matthew W Kelley
- Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, 35 Convent Dr., Bethesda, Maryland 20892, USA.
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Warchol ME. Characterization of supporting cell phenotype in the avian inner ear: implications for sensory regeneration. Hear Res 2006; 227:11-8. [PMID: 17081713 DOI: 10.1016/j.heares.2006.08.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 04/26/2006] [Accepted: 08/30/2006] [Indexed: 10/24/2022]
Abstract
The avian inner ear possesses a remarkable capacity for the regeneration of sensory receptors after acoustic trauma or ototoxicity. Most replacement hair cells are created by renewed cell division within the sensory epithelium, although some new hair cells may also arise through nonmitotic mechanisms. Current data indicate that epithelial supporting cells play an essential role in regeneration, by serving as progenitor cells. In order to become progenitors, however, supporting cells may need to undergo partial dedifferentiation. In this review, I describe molecules that are expressed by supporting cells in the avian ear. Although a number of these molecules are likely to be critical to the maintenance of the supporting cell phenotype, we presently know very little about phenotypic changes in supporting cells during the early phase of regeneration.
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Affiliation(s)
- Mark E Warchol
- Department of Otolaryngology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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Tan J, Shepherd RK. Aminoglycoside-induced degeneration of adult spiral ganglion neurons involves differential modulation of tyrosine kinase B and p75 neurotrophin receptor signaling. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:528-43. [PMID: 16877354 PMCID: PMC1780161 DOI: 10.2353/ajpath.2006.060122] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/13/2006] [Indexed: 01/19/2023]
Abstract
Aminoglycoside antibiotics induce sensorineural hearing loss by destroying hair cells of the organ of Corti, causing progressive secondary degeneration of primary auditory or spiral ganglion neurons (SGNs). Recent studies show that the p75 neurotrophin receptor (NTR) is aberrantly up-regulated under pathological conditions when the neurotrophin receptor tyrosine kinases (Trks) are presumptively down-regulated. We provide in vivo evidence demonstrating that degenerating SGNs induced an augmented p75NTR expression and a coincident reduction of TrkB expression in their peripheral processes. Nuclear transcription factors c-Jun and cyclic AMP response element-binding protein phosphorylated by p75NTR- and TrkB-activated signal pathways, respectively, also showed a corresponding differential modulation, suggesting an activation of apoptotic pathways, coupled to a loss of pro-survival neurotrophic support. Our findings identified brain-derived neurotrophic factor (BDNF) expression in hair and supporting cells of the adult cochlea, and its loss, specifically the mature form, would impair TrkB-induced signaling. The precursor of BDNF (pro-BDNF) is differentially cleaved in aminoglycoside-deafened cochleae, resulting in a predominant up-regulation of a truncated form of pro-BDNF, which colocalized with p75NTR-expressing SGN fibers. Together, these data suggest that an antagonistic interplay of p75NTR and TrkB receptor signaling, possibly modulated by selective BDNF processing, mediates SGN death in vivo.
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Affiliation(s)
- Justin Tan
- Department of Otolaryngology, 32 Gisborne St., East Melbourne, Victoria 3002, Australia.
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Holley MC. Keynote review: The auditory system, hearing loss and potential targets for drug development. Drug Discov Today 2005; 10:1269-82. [PMID: 16214671 DOI: 10.1016/s1359-6446(05)03595-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
There is a huge potential market for the treatment of hearing loss. Drugs are already available to ameliorate predictable, damaging effects of excessive noise and ototoxic drugs. The biggest challenge now is to develop drug-based treatments for regeneration of sensory cells following noise-induced and age-related hearing loss. This requires careful consideration of the physiological mechanisms of hearing loss and identification of key cellular and molecular targets. There are many molecular cues for the discovery of suitable drug targets and a full range of experimental resources are available for initial screening through to functional analysis in vivo. There is now an unparalleled opportunity for translational research.
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Affiliation(s)
- Matthew C Holley
- Department of Biomedical Sciences, Addison Building, Western Bank, Sheffield S10 2TN, UK.
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