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Xiao AY, Lopez IA, Ishiyama G, Ishiyama A. Expression of TGFβ-1 and CTGF in the Implanted Cochlea and its Implication on New Tissue Formation. Otol Neurotol 2024; 45:810-817. [PMID: 38995724 PMCID: PMC11250773 DOI: 10.1097/mao.0000000000004226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
HYPOTHESIS Transforming growth factor beta-1 (TGFβ-1) and connective tissue growth factor (CTGF) are upregulated in the implanted human cochlea. BACKGROUND Cochlear implantation can lead to insertion trauma and intracochlear new tissue formation, which can detrimentally affect implant performance. TGFβ-1 and CTGF are profibrotic proteins implicated in various pathologic conditions, but little is known about their role in the cochlea. The present study aimed to characterize the expression of these proteins in the human implanted cochlea. METHODS Archival human temporal bones (HTB) acquired from 12 patients with previous CI and histopathological evidence of new tissue formation as well as surgical samples of human intracochlear scar tissue surrounding the explanted CI were used in this study. Histopathologic analysis of fibrosis and osteoneogenesis was conducted using H&E. Protein expression was characterized using immunofluorescence. RNA expression from surgical specimens of fibrotic tissue surrounding the CI was quantified using qRT-PCR. RESULTS TGFβ-1 and CTGF protein expressions were upregulated in the areas of fibrosis and osteoneogenesis surrounding the CI HTB. Similarly, surgical samples demonstrated upregulation of protein and mRNA expression of TGFβ-1 and mild upregulation of CTGF compared with control. TGFβ-1 was expressed diffusely within the fibrous capsule, whereas CTGF was expressed in the thickened portion toward the modiolus and the fibrosis-osteoneogensis junction. CONCLUSION To our knowledge, this is the first study to demonstrate increased expression of TGFβ-1 and CTGF in the human implanted cochlea and may provide better understanding of the mechanism behind this pathogenic process to better develop future mitigating interventions.
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Affiliation(s)
- Adam Y. Xiao
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Ivan A. Lopez
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Gail Ishiyama
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Akira Ishiyama
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California
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2
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Nieratschker M, Yildiz E, Gerlitz M, Bera S, Gadenstaetter AJ, Kramer AM, Kwiatkowska M, Mistrik P, Landegger LD, Braun S, Schlingensiepen R, Honeder C, Arnoldner C, Rommelspacher H. A preoperative dose of the pyridoindole AC102 improves the recovery of residual hearing in a gerbil animal model of cochlear implantation. Cell Death Dis 2024; 15:531. [PMID: 39060244 PMCID: PMC11282255 DOI: 10.1038/s41419-024-06854-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 06/19/2024] [Accepted: 06/20/2024] [Indexed: 07/28/2024]
Abstract
Sensorineural hearing loss (SNHL) is the most common sensory deficit worldwide. Due to the heterogeneity of causes for SNHL, effective treatment options remain scarce, creating an unmet need for novel drugs in the field of otology. Cochlear implantation (CI) currently is the only established method to restore hearing function in profound SNHL and deaf patients. The cochlear implant bypasses the non-functioning sensory hair cells (HCs) and electrically stimulates the neurons of the cochlear nerve. CI also benefits patients with residual hearing by combined electrical and auditory stimulation. However, the insertion of an electrode array into the cochlea induces an inflammatory response, characterized by the expression of pro-inflammatory cytokines, upregulation of reactive oxygen species, and apoptosis and necrosis of HCs, putting residual hearing at risk. Here, we characterize the small molecule AC102, a pyridoindole, for its protective effects on residual hearing in CI. In a gerbil animal model of CI, AC102 significantly improves the recovery of hearing thresholds across multiple frequencies and confines the cochlear trauma to the directly mechanically injured area. In addition, AC102 significantly preserves auditory nerve fibers and inner HC synapses throughout the whole cochlea. In vitro experiments in an ethanol challenged HT22 cell-line revealed significant and dose-responsive anti-apoptotic effects following the treatment of with AC102. Further, AC102 treatment resulted in significant downregulation of the expression of pro-inflammatory cytokines in an organotypic ex vivo model of electrode insertion trauma (EIT). These results suggest that AC102's effects are likely elicited during the inflammatory phase of EIT and mediated by anti-apoptotic and anti-inflammatory properties, highlighting AC102 as a promising compound for hearing preservation during CI. Moreover, since the inflammatory response in CI shares similarities to that in other etiologies of SNHL, AC102 may be inferred as a potential general treatment option for various inner ear conditions.
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Affiliation(s)
- Michael Nieratschker
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Erdem Yildiz
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Matthias Gerlitz
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | | | - Anselm J Gadenstaetter
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Anne-Margarethe Kramer
- Center for Biomedical Research and Translational Surgery, Medical University of Vienna, Vienna, Austria
| | | | | | - Lukas D Landegger
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | | | | | - Clemens Honeder
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Christoph Arnoldner
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria.
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Herb M. NADPH Oxidase 3: Beyond the Inner Ear. Antioxidants (Basel) 2024; 13:219. [PMID: 38397817 PMCID: PMC10886416 DOI: 10.3390/antiox13020219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Reactive oxygen species (ROS) were formerly known as mere byproducts of metabolism with damaging effects on cellular structures. The discovery and description of NADPH oxidases (Nox) as a whole enzyme family that only produce this harmful group of molecules was surprising. After intensive research, seven Nox isoforms were discovered, described and extensively studied. Among them, the NADPH oxidase 3 is the perhaps most underrated Nox isoform, since it was firstly discovered in the inner ear. This stigma of Nox3 as "being only expressed in the inner ear" was also used by me several times. Therefore, the question arose whether this sentence is still valid or even usable. To this end, this review solely focuses on Nox3 and summarizes its discovery, the structural components, the activating and regulating factors, the expression in cells, tissues and organs, as well as the beneficial and detrimental effects of Nox3-mediated ROS production on body functions. Furthermore, the involvement of Nox3-derived ROS in diseases progression and, accordingly, as a potential target for disease treatment, will be discussed.
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Affiliation(s)
- Marc Herb
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine, University Hospital Cologne, University of Cologne, 50935 Cologne, Germany;
- German Centre for Infection Research, Partner Site Bonn-Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Aging-Associated Diseases (CECAD), 50931 Cologne, Germany
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Lammers MJW, Young E, Yanai A, Viringipurampeer IA, Le TN, Straatman LV, Westerberg BD, Gregory-Evans K. IGF-1 Mediated Neuroprotective Effects of Olfactory-Derived Mesenchymal Stem Cells on Auditory Hair Cells. J Otolaryngol Head Neck Surg 2024; 53:19160216241258431. [PMID: 38888945 PMCID: PMC11177734 DOI: 10.1177/19160216241258431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/11/2024] [Indexed: 06/20/2024] Open
Abstract
IMPORTANCE Mesenchymal stem cells (MSCs) have the capability of providing ongoing paracrine support to degenerating tissues. Since MSCs can be extracted from a broad range of tissues, their specific surface marker profiles and growth factor secretions can be different. We hypothesized that MSCs derived from different sources might also have different neuroprotective potential. OBJECTIVE In this study, we extracted MSCs from rodent olfactory mucosa and compared their neuroprotective effects on auditory hair cell survival with MSCs extracted from rodent adipose tissue. METHODS Organ of Corti explants were dissected from 41 cochlea and incubated with olfactory mesenchymal stem cells (OMSCs) and adipose mesenchymal stem cells (AMSCs). After 72 hours, Corti explants were fixed, stained, and hair cells counted. Growth factor concentrations were determined in the supernatant and cell lysate using Enzyme-Linked Immunosorbent Assay (ELISA). RESULTS Co-culturing of organ of Corti explants with OMSCs resulted in a significant increase in inner and outer hair cell stereocilia survival, compared to control. Comparisons between both stem cell lines, showed that co-culturing with OMSCs resulted in superior inner and outer hair cell stereocilia survival rates over co-culturing with AMSCs. Assessment of growth factor secretions revealed that the OMSCs secrete significant amounts of insulin-like growth factor 1 (IGF-1). Co-culturing OMSCs with organ of Corti explants resulted in a 10-fold increase in IGF-1 level compared to control, and their secretion was 2 to 3 times higher compared to the AMSCs. CONCLUSIONS This study has shown that OMSCs may mitigate auditory hair cell stereocilia degeneration. Their neuroprotective effects may, at least partially, be ascribed to their enhanced IGF-1 secretory abilities compared to AMSCs.
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Affiliation(s)
- Marc J. W. Lammers
- BC Rotary Hearing and Balance Centre at St. Paul’s Hospital, University of British Columbia, Vancouver, BC, Canada
- Division of Otolaryngology—Head and Neck Surgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada
- Department of Otorhinolaryngology and Head and Neck Surgery, Antwerp University Hospital, Antwerp, Belgium
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Emily Young
- BC Rotary Hearing and Balance Centre at St. Paul’s Hospital, University of British Columbia, Vancouver, BC, Canada
- Division of Otolaryngology—Head and Neck Surgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Anat Yanai
- Department of Ophthalmology and Visual Science, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Canada’s Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Ishaq A. Viringipurampeer
- Department of Ophthalmology and Visual Science, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Trung N. Le
- Sunnybrook Research Institute, Department of Otolaryngology—Head and Neck Surgery, University of Toronto, Toronto, ON, Canada
| | - Louise V. Straatman
- Department of Otolaryngology—Head and Neck Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Brian D. Westerberg
- BC Rotary Hearing and Balance Centre at St. Paul’s Hospital, University of British Columbia, Vancouver, BC, Canada
- Division of Otolaryngology—Head and Neck Surgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Kevin Gregory-Evans
- Department of Ophthalmology and Visual Science, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
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Bader W, Steinacher C, Fischer HT, Glueckert R, Schmutzhard J, Schrott-Fischer A. Effects of Therapeutic Hypothermia on Macrophages in Mouse Cochlea Explants. Int J Mol Sci 2023; 24:8850. [PMID: 37240196 PMCID: PMC10218374 DOI: 10.3390/ijms24108850] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/04/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
Globally, over the next few decades, more than 2.5 billion people will suffer from hearing impairment, including profound hearing loss, and millions could potentially benefit from a cochlea implant. To date, several studies have focused on tissue trauma caused by cochlea implantation. The direct immune reaction in the inner ear after an implantation has not been well studied. Recently, therapeutic hypothermia has been found to positively influence the inflammatory reaction caused by electrode insertion trauma. The present study aimed to evaluate the hypothermic effect on the structure, numbers, function and reactivity of macrophages and microglial cells. Therefore, the distribution and activated forms of macrophages in the cochlea were evaluated in an electrode insertion trauma cochlea culture model in normothermic and mild hypothermic conditions. In 10-day-old mouse cochleae, artificial electrode insertion trauma was inflicted, and then they were cultured for 24 h at 37 °C and 32 °C. The influence of mild hypothermia on macrophages was evaluated using immunostaining of cryosections using antibodies against IBA1, F4/80, CD45 and CD163. A clear influence of mild hypothermia on the distribution of activated and non-activated forms of macrophages and monocytes in the inner ear was observed. Furthermore, these cells were located in the mesenchymal tissue in and around the cochlea, and the activated forms were found in and around the spiral ganglion tissue at 37 °C. Our findings suggest that mild hypothermic treatment has a beneficial effect on immune system activation after electrode insertion trauma.
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Affiliation(s)
| | | | | | | | - Joachim Schmutzhard
- Department of Otorhinolaryngology, Medical University Innsbruck, 6020 Innsbruck, Austria; (W.B.); (C.S.); (H.T.F.); (R.G.); (A.S.-F.)
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Sangaletti R, Tamames I, Yahn SL, Choi JS, Lee JK, King C, Rajguru SM. Mild therapeutic hypothermia protects against inflammatory and proapoptotic processes in the rat model of cochlear implant trauma. Hear Res 2023; 428:108680. [PMID: 36586170 PMCID: PMC9840707 DOI: 10.1016/j.heares.2022.108680] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 12/13/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Mild therapeutic hypothermia (MTH) has been demonstrated to prevent residual hearing loss from surgical trauma associated with cochlear implant (CI) insertion. Here, we aimed to characterize the mechanisms of MTH-induced hearing preservation in CI in a well-established preclinical rodent model. APPROACH Rats were divided into four experimental conditions: MTH-treated and implanted cochleae, cochleae implanted under normothermic conditions, MTH only cochleae and un-operated cochleae (controls). Auditory brainstem responses (ABRs) were recorded at different time points (up to 84 days) to confirm long-term protection and safety of MTH locally applied to the cochlea for 20 min before and after implantation. Transcriptome sequencing profiling was performed on cochleae harvested 24 h post CI and MTH treatment to investigate the potential beneficial effects and underlying active gene expression pathways targeted by the temperature management. RESULTS MTH treatment preserved residual hearing up to 3 months following CI when compared to the normothermic CI group. In addition, MTH applied locally to the cochleae using our surgical approach was safe and did not affect hearing in the long-term. Results of RNA sequencing analysis highlight positive modulation of signaling pathways and gene expression associated with an activation of cellular inflammatory and immune responses against the mechanical damage caused by electrode insertion. SIGNIFICANCE These data suggest that multiple and possibly independent molecular pathways play a role in the protection of residual hearing provided by MTH against the trauma of cochlear implantation.
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Affiliation(s)
- Rachele Sangaletti
- Department of Otolaryngology, University of Miami, Miami, FL, 33136, USA
| | - Ilmar Tamames
- Department of Biomedical Engineering, University of Miami, Miami, FL, 33136, USA
| | - Stephanie Lynn Yahn
- Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, FL, 33136, USA
| | - James Seungyeon Choi
- Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, FL, 33136, USA
| | - Jae K Lee
- Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, FL, 33136, USA
| | | | - Suhrud M Rajguru
- Department of Otolaryngology, University of Miami, Miami, FL, 33136, USA; Department of Biomedical Engineering, University of Miami, Miami, FL, 33136, USA.
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7
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Schmutzhard J, Bader W, Gottfried T, Dejaco D, Glückert R, Dudas J, Schrott-Fischer A. The effects of mild hypothermia on the electrode insertion trauma in a murine whole organ cochlea culture. Front Neurosci 2023; 17:1112243. [PMID: 37123355 PMCID: PMC10133490 DOI: 10.3389/fnins.2023.1112243] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/17/2023] [Indexed: 05/02/2023] Open
Abstract
Introduction Local therapeutic hypothermia (32°C) has been linked experimentally to an otoprotective effect in the electrode insertion trauma. The pathomechanism of the electrode insertion trauma is connected to the activation of apoptosis and necrosis pathways, pro-inflammatory and fibrotic mechanisms. In a whole organ cochlea culture setting the effect of therapeutic hypothermia in an electrode insertion trauma model is evaluated. Material and Methods The cochleae of C57Bl6/J mice (Charles River®, Freiburg, Germany) are cultured for 24 hours at 37°C and 32°C after inserting a fishing line through the round window simulating an insertion trauma. The resulting effect was evaluated for the apoptotic reaction - B-cell-Lymphoma-2-Associated-X-Protein (BAX), B-Cell-Lymphoma-2-Protein (BCL2) and Cleaved-Caspase-3 (CC3) -, the inflammatory response - Tumor-Necrosis-Factor-Alpha (TNFα), Interleukin-1-Beta (IL-1Imm) and Cyclooxygenase-2 (COX2) - and proliferation process - Transforming-Growth-Factor-Beta-1 (TGFβ1) - using immunohistochemistry and real-time PCR technique. A minimum of 12 cochlea per experiment were used. Results A pro-apoptotic situation was observed in the normothermic group (BAX, CC3 ˃ Bcl2) whereas an anti-apoptotic constellation was found at 32°C culture conditions (BAX, CC3 < Bcl2). Furthermore the effect of the IT knowing to effect the pro-inflammatory cytokine (TNFα, Il1β) and enzyme (COX2) expression has been reproduced. This reaction was reversed with the application of therapeutic hypothermia resulting in significant lower pro-inflammatory cytokine (TNFα, Il1β) and enzyme (COX2) expression. TGFβ1 was increased by hypothermia. Discussion Concluding a protective effect of hypothermia on the experimental electrode insertion trauma can be described by an anti-apoptotic and anti-inflammatory reaction.
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Warnecke A, Staecker H, Rohde E, Gimona M, Giesemann A, Szczepek AJ, Di Stadio A, Hochmair I, Lenarz T. Extracellular Vesicles in Inner Ear Therapies-Pathophysiological, Manufacturing, and Clinical Considerations. J Clin Med 2022; 11:jcm11247455. [PMID: 36556073 PMCID: PMC9788356 DOI: 10.3390/jcm11247455] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/09/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022] Open
Abstract
(1) Background: Sensorineural hearing loss is a common and debilitating condition. To date, comprehensive pharmacologic interventions are not available. The complex and diverse molecular pathology that underlies hearing loss may limit our ability to intervene with small molecules. The current review foccusses on the potential for the use of extracellular vesicles in neurotology. (2) Methods: Narrative literature review. (3) Results: Extracellular vesicles provide an opportunity to modulate a wide range of pathologic and physiologic pathways and can be manufactured under GMP conditions allowing for their application in the human inner ear. The role of inflammation in hearing loss with a focus on cochlear implantation is shown. How extracellular vesicles may provide a therapeutic option for complex inflammatory disorders of the inner ear is discussed. Additionally, manufacturing and regulatory issues that need to be addressed to develop EVs as advanced therapy medicinal product for use in the inner ear are outlined. (4) Conclusion: Given the complexities of inner ear injury, novel therapeutics such as extracellular vesicles could provide a means to modulate inflammation, stress pathways and apoptosis in the inner ear.
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Affiliation(s)
- Athanasia Warnecke
- Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany
- Cluster of Excellence of the German Research Foundation (DFG; “Deutsche Forschungsgemeinschaft”) “Hearing4all”, 30625 Hannover, Germany
- Correspondence:
| | - Hinrich Staecker
- Department of Otolaryngology Head and Neck Surgery, University of Kansas School of Medicine, Rainbow Blvd., Kansas City, KS 66160, USA
| | - Eva Rohde
- GMP Unit, Spinal Cord Injury & Tissue Regeneration Centre Salzburg (SCI-TReCS), Paracelsus Medical University, 5020 Salzburg, Austria
- Transfer Centre for Extracellular Vesicle Theralytic Technologies (EV-TT), 5020 Salzburg, Austria
- Department of Transfusion Medicine, University Hospital, Salzburger Landeskliniken GesmbH (SALK) Paracelsus Medical University, 5020 Salzburg, Austria
| | - Mario Gimona
- GMP Unit, Spinal Cord Injury & Tissue Regeneration Centre Salzburg (SCI-TReCS), Paracelsus Medical University, 5020 Salzburg, Austria
- Transfer Centre for Extracellular Vesicle Theralytic Technologies (EV-TT), 5020 Salzburg, Austria
- Research Program “Nanovesicular Therapies”, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Anja Giesemann
- Department of Diagnostic and Interventional Neuroradiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Agnieszka J. Szczepek
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
- Faculty of Medicine and Health Sciences, University of Zielona Gora, 65-046 Zielona Gora, Poland
| | - Arianna Di Stadio
- Department GF Ingrassia, University of Catania, 95124 Catania, Italy
| | | | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany
- Cluster of Excellence of the German Research Foundation (DFG; “Deutsche Forschungsgemeinschaft”) “Hearing4all”, 30625 Hannover, Germany
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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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Schröder HC, Wang X, Neufurth M, Wang S, Müller WEG. Biomimetic Polyphosphate Materials: Toward Application in Regenerative Medicine. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2022; 61:83-130. [PMID: 35697938 DOI: 10.1007/978-3-031-01237-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In recent years, inorganic polyphosphate (polyP) has attracted increasing attention as a biomedical polymer or biomaterial with a great potential for application in regenerative medicine, in particular in the fields of tissue engineering and repair. The interest in polyP is based on two properties of this physiological polymer that make polyP stand out from other polymers: polyP has morphogenetic activity by inducing cell differentiation through specific gene expression, and it functions as an energy store and donor of metabolic energy, especially in the extracellular matrix or in the extracellular space. No other biopolymer applicable in tissue regeneration/repair is known that is endowed with this combination of properties. In addition, polyP can be fabricated both in the form of a biologically active coacervate and as biomimetic amorphous polyP nano/microparticles, which are stable and are activated by transformation into the coacervate phase after contact with protein/body fluids. PolyP can be used in the form of various metal salts and in combination with various hydrogel-forming polymers, whereby (even printable) hybrid materials with defined porosities and mechanical and biological properties can be produced, which can even be loaded with cells for 3D cell printing or with drugs and support the growth and differentiation of (stem) cells as well as cell migration/microvascularization. Potential applications in therapy of bone, cartilage and eye disorders/injuries and wound healing are summarized and possible mechanisms are discussed.
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Affiliation(s)
- Heinz C Schröder
- ERC Advanced Investigator Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Xiaohong Wang
- ERC Advanced Investigator Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Meik Neufurth
- ERC Advanced Investigator Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Shunfeng Wang
- ERC Advanced Investigator Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Werner E G Müller
- ERC Advanced Investigator Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
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Dexamethasone for Inner Ear Therapy: Biocompatibility and Bio-Efficacy of Different Dexamethasone Formulations In Vitro. Biomolecules 2021; 11:biom11121896. [PMID: 34944539 PMCID: PMC8699596 DOI: 10.3390/biom11121896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 01/27/2023] Open
Abstract
Dexamethasone is widely used in preclinical studies and clinical trials to treat inner ear disorders. The results of those studies vary widely, maybe due to the different dexamethasone formulations used. Laboratory (lab) and medical grade (med) dexamethasone (DEX, C22H29FO5) and dexamethasone dihydrogen phosphate-disodium (DPS, C22H28FNa2O8P) were investigated for biocompatibility and bio-efficacy in vitro. The biocompatibility of each dexamethasone formulation in concentrations from 0.03 to 10,000 µM was evaluated using an MTT assay. The concentrations resulting in the highest cell viability were selected to perform a bio-efficiency test using a TNFα-reduction assay. All dexamethasone formulations up to 900 µM are biocompatible in vitro. DPS-lab becomes toxic at 1000 µM and DPS-med at 2000 µM, while DEX-lab and DEX-med become toxic at 4000 µM. Bio-efficacy was evaluated for DEX-lab and DPS-med at 300 µM, for DEX-med at 60 µM, and DPS-lab at 150 µM, resulting in significantly reduced expression of TNFα, with DPS-lab having the highest effect. Different dexamethasone formulations need to be applied in different concentration ranges to be biocompatible. The concentration to be applied in future studies should carefully be chosen based on the respective dexamethasone form, application route and duration to ensure biocompatibility and bio-efficacy.
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12
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Hunt C, Hartford SA, White D, Pefanis E, Hanna T, Herman C, Wiley J, Brown H, Su Q, Xin Y, Voronin D, Nguyen H, Altarejos J, Crosby K, Haines J, Cancelarich S, Drummond M, Moller-Tank S, Malpass R, Buckley J, Del Pilar Molina-Portela M, Droguett G, Frendewey D, Chiao E, Zambrowicz B, Gong G. Tissue-specific activation of gene expression by the Synergistic Activation Mediator (SAM) CRISPRa system in mice. Nat Commun 2021; 12:2770. [PMID: 33986266 PMCID: PMC8119962 DOI: 10.1038/s41467-021-22932-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/06/2021] [Indexed: 02/03/2023] Open
Abstract
CRISPR-based transcriptional activation is a powerful tool for functional gene interrogation; however, delivery difficulties have limited its applications in vivo. Here, we created a mouse model expressing all components of the CRISPR-Cas9 guide RNA-directed Synergistic Activation Mediator (SAM) from a single transcript that is capable of activating target genes in a tissue-specific manner. We optimized Lipid Nanoparticles and Adeno-Associated Virus guide RNA delivery approaches to achieve expression modulation of one or more genes in vivo. We utilized the SAM mouse model to generate a hypercholesteremia disease state that we could bidirectionally modulate with various guide RNAs. Additionally, we applied SAM to optimize gene expression in a humanized Transthyretin mouse model to recapitulate human expression levels. These results demonstrate that the SAM gene activation platform can facilitate in vivo research and drug discovery.
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Affiliation(s)
| | | | - Derek White
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA
| | | | | | | | | | | | - Qi Su
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA
| | - Yurong Xin
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA
| | | | - Hien Nguyen
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA
| | | | - Keith Crosby
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA
| | | | | | | | | | - Ryan Malpass
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA
| | | | | | | | | | - Eric Chiao
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA
| | | | - Guochun Gong
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA.
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13
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Gao J, Yi H. Molecular mechanisms and roles of inflammatory responses on low-frequency residual hearing after cochlear implantation. J Otol 2021; 17:54-58. [PMID: 35140760 PMCID: PMC8811416 DOI: 10.1016/j.joto.2021.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/25/2021] [Accepted: 03/02/2021] [Indexed: 01/28/2023] Open
Abstract
Preservation of low-frequency residual hearing is very important for combined electro-acoustic stimulation after cochlear implantation. However, in clinical practice, loss of low-frequency residual hearing often occurs after cochlear implantation and its mechanisms remain unclear. Factors affecting low-frequency residual hearing after cochlear implantation are one of the hot spots in current research. Inflammation induced by injury associated with cochlear implantation is deemed to be significant, as it may give rise to low-frequency residual hearing loss by interfering with the blood labyrinth barrier and neural synapses. Pathological changes along the pathway for low-frequency auditory signals transmission may include latent factors such as damage to neuroepithelial structures, synapses, stria vascularis and other ultrastructures. In this review, current research on mechanisms of low-frequency residual hearing loss after cochlear implantation and possible roles of inflammatory responses are summarized.
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14
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Perin P, Marino F, Varela-Nieto I, Szczepek AJ. Editorial: Neuroimmunology of the Inner Ear. Front Neurol 2021; 12:635359. [PMID: 33633679 PMCID: PMC7899967 DOI: 10.3389/fneur.2021.635359] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/07/2021] [Indexed: 12/20/2022] Open
Affiliation(s)
- Paola Perin
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
| | - Franca Marino
- Center of Research in Medical Pharmacology University of Insubria, Varese, Italy
| | - Isabel Varela-Nieto
- Institute for Biomedical Research "Alberto Sols" (IIBM), Spanish National Research Council-Autonomous University of Madrid (CSIC-UAM), Madrid, Spain.,Rare Diseases Networking Biomedical Research Centre, Centro de Investigación Biomédica en Red, Carlos III Institute of Health, Madrid, Spain.,La Paz Hospital Institute for Health Research (IdiPAZ), Madrid, Spain
| | - Agnieszka J Szczepek
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Faculty of Medicine and Health Sciences, University of Zielona Gora, Zielona Gora, Poland
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15
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Neufurth M, Wang X, Wang S, Schröder HC, Müller WEG. Caged Dexamethasone/Quercetin Nanoparticles, Formed of the Morphogenetic Active Inorganic Polyphosphate, are Strong Inducers of MUC5AC. Mar Drugs 2021; 19:64. [PMID: 33513822 PMCID: PMC7910845 DOI: 10.3390/md19020064] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/17/2021] [Accepted: 01/24/2021] [Indexed: 02/07/2023] Open
Abstract
Inorganic polyphosphate (polyP) is a widely distributed polymer found from bacteria to animals, including marine species. This polymer exhibits morphogenetic as well as antiviral activity and releases metabolic energy after enzymatic hydrolysis also in human cells. In the pathogenesis of the coronavirus disease 2019 (COVID-19), the platelets are at the frontline of this syndrome. Platelets release a set of molecules, among them polyP. In addition, the production of airway mucus, the first line of body defense, is impaired in those patients. Therefore, in this study, amorphous nanoparticles of the magnesium salt of polyP (Mg-polyP-NP), matching the size of the coronavirus SARS-CoV-2, were prepared and loaded with the secondary plant metabolite quercetin or with dexamethasone to study their effects on the respiratory epithelium using human alveolar basal epithelial A549 cells as a model. The results revealed that both compounds embedded into the polyP nanoparticles significantly increased the steady-state-expression of the MUC5AC gene. This mucin species is the major mucus glycoprotein present in the secreted gel-forming mucus. The level of gene expression caused by quercetin or with dexamethasone, if caged into polyP NP, is significantly higher compared to the individual drugs alone. Both quercetin and dexamethasone did not impair the growth-supporting effect of polyP on A549 cells even at concentrations of quercetin which are cytotoxic for the cells. A possible mechanism of the effects of the two drugs together with polyP on mucin expression is proposed based on the scavenging of free oxygen species and the generation of ADP/ATP from the polyP, which is needed for the organization of the protective mucin-based mucus layer.
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Affiliation(s)
| | - Xiaohong Wang
- ERC Advanced Investigator Grant Research Group, Institute for Physiological Chemistry, University Medical Center, Johannes Gutenberg University, Duesbergweg 6, 55128 Mainz, Germany; (M.N.); (S.W.); (H.C.S.)
| | | | | | - Werner E. G. Müller
- ERC Advanced Investigator Grant Research Group, Institute for Physiological Chemistry, University Medical Center, Johannes Gutenberg University, Duesbergweg 6, 55128 Mainz, Germany; (M.N.); (S.W.); (H.C.S.)
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16
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Bader W, Gottfried T, Degenhart G, Johnson Chacko L, Sieber D, Riechelmann H, Fischer N, Hoermann R, Glueckert R, Schrott-Fischer A, Schmutzhard J. Measurement of the Intracochlear Hypothermia Distribution Utilizing Tympanic Cavity Hypothermic Rinsing Technique in a Cochlea Hypothermia Model. Front Neurol 2021; 11:620691. [PMID: 33505351 PMCID: PMC7830138 DOI: 10.3389/fneur.2020.620691] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/07/2020] [Indexed: 11/13/2022] Open
Abstract
Introduction: Cochlea implants can cause severe trauma leading to intracochlear apoptosis, fibrosis, and eventually to loss of residual hearing. Mild hypothermia has been shown to reduce toxic or mechanical noxious effects, which can result in inflammation and subsequent hearing loss. This paper evaluates the usability of standard surgical otologic rinsing as cooling medium during cochlea implantation as a potential hearing preservation technique. Material and Methods: Three human temporal bones were prepared following standard mastoidectomy and posterior tympanotomy. Applying a retrocochlear approach leaving the mastoidectomy side intact, temperature probes were placed into the basal turn (n = 4), the middle turn (n = 2), the helicotrema, and the modiolus. Temperature probe positions were visualized by microcomputed tomography (μCT) imaging and manually segmented using Amira® 7.6. Through the posterior tympanotomy, the tympanic cavity was rinsed at 37°C in the control group, at room temperature (in the range between 22 and 24°C), and at iced water conditions. Temperature changes were measured in the preheated temporal bone. In each temperature model, rinsing was done for 20 min at the pre-specified temperatures measured in 0.5-s intervals. At least five repetitions were performed. Data were statistically analyzed using pairwise t-tests with Bonferroni correction. Results: Steady-state conditions achieved in all three different temperature ranges were compared in periods between 150 and 300 s. Temperature in the inner ear started dropping within the initial 150 s. Temperature probes placed at basal turn, the helicotrema, and middle turn detected statistically significant fall in temperature levels following body temperature rinses. Irrigation at iced conditions lead to the most significant temperature drops. The curves during all measurements remained stable with 37°C rinses. Conclusion: Therapeutic hypothermia is achieved with standard surgical irrigation fluid, and temperature gradients are seen along the cochlea. Rinsing of 120 s duration results in a therapeutic local hypothermia throughout the cochlea. This otoprotective procedure can be easily realized in clinical practice.
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Affiliation(s)
- Werner Bader
- Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Timo Gottfried
- Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Gerald Degenhart
- Department of Radiology, University Clinics Innsbruck, Innsbruck, Austria
| | - Lejo Johnson Chacko
- Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Daniel Sieber
- MED-EL Medical Electronics GesmbH, Research and Development, Innsbruck, Austria
| | - Herbert Riechelmann
- Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Natalie Fischer
- Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Romed Hoermann
- Department of Anatomy, Histology, and Embryology, Medical University Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | | | - Joachim Schmutzhard
- Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
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Swiderski DL, Colesa DJ, Hughes AP, Raphael Y, Pfingst BE. Relationships between Intrascalar Tissue, Neuron Survival, and Cochlear Implant Function. J Assoc Res Otolaryngol 2020; 21:337-352. [PMID: 32691251 PMCID: PMC7445211 DOI: 10.1007/s10162-020-00761-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 07/12/2020] [Indexed: 12/15/2022] Open
Abstract
Fibrous tissue and/or new bone are often found surrounding a cochlear implant in the cochlear scalae. This new intrascalar tissue could potentially limit cochlear implant function by increasing impedance and altering signaling pathways between the implant and the auditory nerve. In this study, we investigated the relationship between intrascalar tissue and 5 measures of implant function in guinea pigs. Variation in both spiral ganglion neuron (SGN) survival and intrascalar tissue was produced by implanting hearing ears, ears deafened with neomycin, and neomycin-deafened ears treated with a neurotrophin. We found significant effects of SGN density on 4 functional measures but adding intrascalar tissue level to the analysis did not explain more variation in any measure than was explained by SGN density alone. These results suggest that effects of intrascalar tissue on electrical hearing are relatively unimportant in comparison to degeneration of the auditory nerve, although additional studies in human implant recipients are still needed to assess the effects of this tissue on complex hearing tasks like speech perception. The results also suggest that efforts to minimize the trauma that aggravates both tissue development and SGN loss could be beneficial.
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Affiliation(s)
- Donald L Swiderski
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Deborah J Colesa
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Aaron P Hughes
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Bryan E Pfingst
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
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18
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Scheper V, Schmidtheisler M, Lasch F, von der Leyen H, Koch A, Schwieger J, Büchner A, Lesinski-Schiedat A, Lenarz T. Randomized placebo-controlled clinical trial investigating the effect of antioxidants and a vasodilator on overall safety and residual hearing preservation in cochlear implant patients. Trials 2020; 21:643. [PMID: 32665006 PMCID: PMC7362557 DOI: 10.1186/s13063-020-04522-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/16/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The standard therapy for patients suffering from sensorineural hearing loss is cochlear implantation. The insertion of the electrode array into the cochlea, with potential mechanical trauma and the presence of this foreign body inside the cochlea, may lead to free radical formation and reduced blood perfusion of the cochlea which can result in a loss of residual hearing. Studies have suggested that a particular combination of the antioxidants vitamins A, C and E as well as the vasodilator magnesium (together: ACEMg) may protect the residual hearing. METHODS The potential protective effect of ACEMg on residual hearing preservation in cochlear implant (CI) patients was investigated in a single-centre, randomized, placebo-controlled, double-blind phase II clinical trial. CI candidates with some residual hearing in low frequencies receiving MED-EL implants of different FLEX electrode array lengths were treated with ACEMg tablets or placebo respectively 2 days preoperatively and up to 3 months postoperatively. The study objective was to demonstrate that ACEMg is more efficacious than placebo in preserving residual hearing during cochlear implantation by comparing the hearing loss (change in hearing thresholds at 500 Hz from baseline) 3 months after the first fitting between the two treatment groups and to investigate the treatments' safety. RESULTS Fifty-one patients were included in the study, which had to be terminated before the recruitment goal was reached because of IMP-resupply mismanagement of one partner. In the intention-to-treat population, 25 patients were treated with ACEMg and 24 patients with placebo. The mean hearing loss at 500 Hz was (± 15.84) 30.21 dB (placebo) or (± 17.56) 26.00 dB (ACEMg) 3 months after the initial fitting. Adjusting the postoperative hearing loss for the baseline residual hearing, planned electrode length and surgeon results in 8.01 dB reduced hearing loss in ACEMg-treated patients compared to placebo-treated ones. The safety analysis revealed that ACEMg was generally well-tolerated with adverse event frequencies below the placebo level. CONCLUSION This is the first clinical trial investigating a drug effect on residual hearing in CI patients. These first-in-man data may suggest that a perioperative oral administration of ACEMg is safe and may provide protection of residual hearing in CI patients. TRIAL REGISTRATION EU Clinical Trial Register No. 2012-005002-22 . Registered on 6 December 2013. FUNDING European Commission FP7-HEALTH-2012-INNOVATION-2.
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Affiliation(s)
- Verena Scheper
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
- Cluster of Excellence Hearing4all, Oldenburg, Germany
| | - Melanie Schmidtheisler
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
- Cluster of Excellence Hearing4all, Oldenburg, Germany
| | - Florian Lasch
- Institute for Biostatistics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Heiko von der Leyen
- Hannover Clinical Trial Center, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Armin Koch
- Institute for Biostatistics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Jana Schwieger
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Andreas Büchner
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
- Cluster of Excellence Hearing4all, Oldenburg, Germany
| | - Anke Lesinski-Schiedat
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
- Cluster of Excellence Hearing4all, Oldenburg, Germany
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19
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Shah V, Mittal R, Shahal D, Sinha P, Bulut E, Mittal J, Eshraghi AA. Evaluating the Efficacy of Taurodeoxycholic Acid in Providing Otoprotection Using an in vitro Model of Electrode Insertion Trauma. Front Mol Neurosci 2020; 13:113. [PMID: 32760249 PMCID: PMC7372968 DOI: 10.3389/fnmol.2020.00113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 06/02/2020] [Indexed: 12/13/2022] Open
Abstract
Cochlear implants (CIs) are widely used to provide auditory rehabilitation to individuals having severe to profound sensorineural hearing loss (SNHL). However, insertion of electrode leads to inner trauma and activation of inflammatory and apoptotic signaling cascades resulting in loss of residual hearing in implanted individuals. Pharmaceutical interventions that can target these signaling cascades hold great potential for preserving residual hearing by preventing sensory cell damage. Bile salts have shown efficacy in various regions of the body as powerful antioxidants and anti-inflammatory agents. However, their efficacy against inner ear trauma has never been explored. The objective of this study was to determine whether taurodeoxycholic acid (TDCA), a bile salt derivative, can prevent sensory cell damage employing an in vitro model of electrode insertion trauma (EIT). The organ of Corti (OC) explants were dissected from postnatal day 3 (P-3) rats and placed in serum-free media. Explants were divided into control and experimental groups: (1) untreated controls; (2) EIT; (3) EIT+ TDCA (different concentrations). Hair cell (HC) density, analyses of apoptosis pathway (cleaved caspase 3), levels of reactive oxygen species (ROS) as well as inducible nitric oxide synthase (iNOS) activity and Mitochondrial Membrane Potential (MMP) were assayed. Treatment with TDCA provided significant otoprotection against HC loss in a dose-dependent manner. The molecular mechanisms underlying otoprotection involved decreasing oxidative stress, lowering levels of iNOS, and abrogating generation of cleaved caspase 3. The results of the present study suggest that TDCA provides efficient otoprotection against EIT, in vitro and should be explored for developing pharmaceutical interventions to preserve residual hearing post-cochlear implantation.
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Affiliation(s)
- Viraj Shah
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Rahul Mittal
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - David Shahal
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Priyanka Sinha
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Erdogan Bulut
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Jeenu Mittal
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Adrien A Eshraghi
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States.,Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, United States.,Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
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20
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Cochlear Implantation With a Dexamethasone Eluting Electrode Array: Functional and Anatomical Changes in Non-Human Primates. Otol Neurotol 2020; 41:e812-e822. [DOI: 10.1097/mao.0000000000002686] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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21
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Peter MN, Paasche G, Reich U, Lenarz T, Warnecke A. Differential Effects of Low- and High-Dose Dexamethasone on Electrically Induced Damage of the Cultured Organ of Corti. Neurotox Res 2020; 38:487-497. [PMID: 32495312 PMCID: PMC7334252 DOI: 10.1007/s12640-020-00228-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 05/02/2020] [Accepted: 05/19/2020] [Indexed: 12/29/2022]
Abstract
An increased number of patients with residual hearing are undergoing cochlear implantation. A subset of these experience delayed hearing loss post-implantation, and the aetiology of this loss is not well understood. Our previous studies suggest that electrical stimulation can induce damage to hair cells in organ of Corti (OC) organotypic cultures. Dexamethasone has the potential to protect residual hearing due to its multiple effects on cells and tissue (e.g., anti-inflammatory, free radical scavenger). We therefore hypothesized that dexamethasone treatment could prevent electrical stimulation induced changes in the OC. Organ of Corti explants from neonatal rats (P2–4) were cultured for 24 h with two different concentrations of dexamethasone. Thereafter, OC were subjected to a charge-balanced biphasic pulsed electrical stimulation (0.44–2 mA) for a further 24 h. Unstimulated dexamethasone-treated OC served as controls. Outcome analysis included immunohistochemical labelling of ribbon synapses, histochemical analysis of free reactive oxygen species and morphological analysis of stereocilia bundles. Overall, the protective effects of dexamethasone on electrically induced damage in cochlear explants were moderate. High-dose dexamethasone protected bundle integrity at higher current levels. Low-dose dexamethasone tended to increase ribbon density in the apical region.
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Affiliation(s)
- Marvin N Peter
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Gerrit Paasche
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Cluster of Excellence "Hearing4all" of the German Research Foundation, Hannover, Germany
| | - Uta Reich
- Department of Otorhinolaryngology, Head and Neck Surgery, Berlin Institute of Health, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Cluster of Excellence "Hearing4all" of the German Research Foundation, Hannover, Germany
| | - Athanasia Warnecke
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. .,Cluster of Excellence "Hearing4all" of the German Research Foundation, Hannover, Germany.
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22
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Evaluating the Efficacy of L-N-acetylcysteine and Dexamethasone in Combination to Provide Otoprotection for Electrode Insertion Trauma. J Clin Med 2020; 9:jcm9030716. [PMID: 32155788 PMCID: PMC7141216 DOI: 10.3390/jcm9030716] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 02/27/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Electrode insertion trauma (EIT) during cochlear implantation (CI) can cause loss of residual hearing. L-N-acetylcysteine (L-NAC) and dexamethasone (Dex) have been individually shown to provide otoprotection albeit at higher concentrations that may be associated with adverse effects. Objective/Aims: The aim of this study is to determine whether L-NAC and Dex could be combined to decrease their effective dosage. MATERIALS AND METHODS The organ of Corti (OC) explants were divided into various groups: 1) control; 2) EIT; 3) EIT treated with different concentrations of Dex; 4) EIT treated with different concentrations of L-NAC; 5) EIT treated with L-NAC and Dex in combination. Hair cell (HC) density, levels of oxidative stress, proinflammatory cytokines and nitric oxide (NO) was determined. RESULTS There was a significant loss of HCs in explants subjected to EIT compared to the control group. L-NAC and Dex in combination was able to provide significant otoprotection at lower concentrations compared to individual drugs. CONCLUSIONS AND SIGNIFICANCE A combination containing L-NAC and Dex is effective in protecting sensory cells at lower protective doses than each compound separately. These compounds can be combined allowing a decrease of potential side effects of each compound and providing significant otoprotection for EIT.
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Eshraghi AA, Wolfovitz A, Yilmazer R, Garnham C, Yilmazer AB, Bas E, Ashman P, Roell J, Bohorquez J, Mittal R, Hessler R, Sieber D, Mittal J. Otoprotection to Implanted Cochlea Exposed to Noise Trauma With Dexamethasone Eluting Electrode. Front Cell Neurosci 2019; 13:492. [PMID: 31824265 PMCID: PMC6882736 DOI: 10.3389/fncel.2019.00492] [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: 01/31/2019] [Accepted: 10/21/2019] [Indexed: 12/23/2022] Open
Abstract
Cochlear implantation (CI) is now widely used to provide auditory rehabilitation to individuals having severe to profound sensorineural hearing loss (SNHL). However, CI can lead to electrode insertion trauma (EIT) that can cause damage to sensory cells in the inner ear resulting in loss of residual hearing. Even with soft surgical techniques where there is minimal macroscopic damage, we can still observe the generation of molecular events that may initiate programmed cell death via various mechanisms such as oxidative stress, the release of pro-inflammatory cytokines, and activation of the caspase pathway. In addition, individuals with CI may be exposed to noise trauma (NT) due to occupation and leisure activities that may affect their hearing ability. Recently, there has been an increased interest in the auditory community to determine the efficacy of drug-eluting electrodes for the protection of residual hearing. The objective of this study is to determine the effect of NT on implanted cochlea as well as the otoprotective efficacy of dexamethasone eluting electrode to implanted cochlea exposed to NT in a guinea pig model of CI. Animals were divided into five groups: EIT with dexamethasone eluting electrode exposed to NT; EIT exposed to NT; NT only; EIT only and naïve animals (control group). The hearing thresholds were determined by auditory brainstem recordings (ABRs). The cochlea was harvested and analyzed for transcript levels of inflammation, apoptosis and fibrosis genes. We observed that threshold shifts were significantly higher in EIT, NT or EIT + NT groups compared to naive animals at all the tested frequencies. The dexamethasone eluting electrode led to a significant decrease in hearing threshold shifts in implanted animals exposed to NT. Proapoptotic tumor necrosis factor-α [TNF-α, TNF-α receptor 1a (TNFαR1a)] and pro-fibrotic transforming growth factor β1 (TGFβ) genes were more than two-fold up-regulated following EIT and EIT + NT compared to the control group. The use of dexamethasone releasing electrode significantly decreased the transcript levels of pro-apoptotic and pro-fibrotic genes. The dexamethasone releasing electrode has shown promising results for hearing protection in implanted animals exposed to NT. The results of this study suggest that dexamethasone releasing electrode holds great potential in developing effective treatment modalities for NT in the implanted cochlea.
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Affiliation(s)
- Adrien A Eshraghi
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States.,Department of Neurological Surgery, Miller School of Medicine, Miami, FL, United States.,Department of Biomedical Engineering, University of Miami, Miami, Coral Gables, FL, United States
| | - Amit Wolfovitz
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States
| | - Rasim Yilmazer
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States
| | | | - Ayca Baskadem Yilmazer
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States
| | - Esperanza Bas
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States
| | - Peter Ashman
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States
| | - Jonathan Roell
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States
| | - Jorge Bohorquez
- Department of Biomedical Engineering, University of Miami, Miami, Coral Gables, FL, United States
| | - Rahul Mittal
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States
| | | | | | - Jeenu Mittal
- Department of Otolaryngology, University of Miami Hearing Research Laboratory, Miller School of Medicine, Miami, FL, United States
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Warnecke A, Prenzler NK, Schmitt H, Daemen K, Keil J, Dursin M, Lenarz T, Falk CS. Defining the Inflammatory Microenvironment in the Human Cochlea by Perilymph Analysis: Toward Liquid Biopsy of the Cochlea. Front Neurol 2019; 10:665. [PMID: 31293504 PMCID: PMC6603180 DOI: 10.3389/fneur.2019.00665] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 06/06/2019] [Indexed: 12/20/2022] Open
Abstract
The molecular pathomechanisms in the majority of patients suffering from acute or progressive sensorineural hearing loss cannot be determined yet. The size and the complex architecture of the cochlea make biopsy and in-depth histological analyses impossible without severe damage of the organ. Thus, histopathology correlated to inner disease is only possible after death. The establishment of a technique for perilymph sampling during cochlear implantation may enable a liquid biopsy and characterization of the cochlear microenvironment. Inflammatory processes may not only participate in disease onset and progression in the inner ear, but may also control performance of the implant. However, little is known about cytokines and chemokines in the human inner ear as predictive markers for cochlear implant performance. First attempts to use multiplex protein arrays for inflammatory markers were successful for the identification of cytokines, chemokines, and endothelial markers present in the human perilymph. Moreover, unsupervised cluster and principal component analyses were used to group patients by lead cytokines and to correlate certain proteins to clinical data. Endothelial and epithelial factors were detected at higher concentrations than typical pro-inflammatory cytokines such as TNF-a or IL-6. Significant differences in VEGF family members have been observed comparing patients with deafness to patients with residual hearing with significantly reduced VEGF-D levels in patients with deafness. In addition, there is a trend toward higher IGFBP-1 levels in these patients. Hence, endothelial and epithelial factors in combination with cytokines may present robust biomarker candidates and will be investigated in future studies in more detail. Thus, multiplex protein arrays are feasible in very small perilymph samples allowing a qualitative and quantitative analysis of inflammatory markers. More results are required to advance this method for elucidating the development and course of specific inner ear diseases or for perioperative characterization of cochlear implant patients.
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Affiliation(s)
- Athanasia Warnecke
- Department of Otolaryngology, Hannover Medical School, Hanover, Germany.,Cluster of Excellence of the German Research Foundation (DFG; "Deutsche Forschungsgemeinschaft") "Hearing4all", Oldenburg, Germany
| | - Nils K Prenzler
- Department of Otolaryngology, Hannover Medical School, Hanover, Germany
| | - Heike Schmitt
- Department of Otolaryngology, Hannover Medical School, Hanover, Germany.,Cluster of Excellence of the German Research Foundation (DFG; "Deutsche Forschungsgemeinschaft") "Hearing4all", Oldenburg, Germany
| | - Kerstin Daemen
- Hannover Medical School, Institute of Transplant Immunology, Hanover, Germany
| | - Jana Keil
- Hannover Medical School, Institute of Transplant Immunology, Hanover, Germany
| | - Martin Dursin
- Department of Otolaryngology, Hannover Medical School, Hanover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Hanover, Germany.,Cluster of Excellence of the German Research Foundation (DFG; "Deutsche Forschungsgemeinschaft") "Hearing4all", Oldenburg, Germany
| | - Christine S Falk
- Hannover Medical School, Institute of Transplant Immunology, Hanover, Germany
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Bas E, Anwar MR, Goncalves S, Dinh CT, Bracho OR, Chiossone JA, Van De Water TR. Laminin-coated electrodes improve cochlear implant function and post-insertion neuronal survival. Neuroscience 2019; 410:97-107. [PMID: 31059743 DOI: 10.1016/j.neuroscience.2019.04.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 04/17/2019] [Accepted: 04/24/2019] [Indexed: 12/20/2022]
Abstract
The benefits of Cochlear implant (CI) technology depend among other factors on the proximity of the electrode array to the spiral ganglion neurons. Laminin, a component of the extracellular matrix, regulates Schwann cell proliferation and survival as well as reorganization of actin fibers within their cytoskeleton, which is necessary for myelination of peripheral axons. In this study we explore the effectiveness of laminin-coated electrodes in promoting neuritic outgrowth from auditory neurons towards the electrode array and the ability to reduce acoustic and electric auditory brainstem response (i.e. aABR and eABR) thresholds. In vitro: Schwann cells and neurites are attracted towards laminin-coated surfaces with longer neuritic processes in laminin-coated dishes compared to uncoated dishes. In vivo: Animals implanted with laminin-coated electrodes experience significant decreases in eABR and aABR thresholds at selected frequencies compared to the results from the uncoated electrodes group. At 1 month post implantation there were a greater number of spiral ganglion neurons and neuritic processes projecting into the scala tympani of animals implanted with laminin-coated electrodes compared to animals with uncoated electrodes. These data suggest that Schwann cells are attracted towards laminin-coated electrodes and promote neuritic outgrowth/ guidance and promote the survival of spiral ganglion neurons following electrode insertion trauma.
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Affiliation(s)
- Esperanza Bas
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America.
| | - Mir R Anwar
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Stefania Goncalves
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Christine T Dinh
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Olena R Bracho
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Juan A Chiossone
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Thomas R Van De Water
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
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Bas E, Anwar MR, Van De Water TR. TGF β‐1 and WNT Signaling Pathways Collaboration Associated with Cochlear Implantation Trauma‐Induced Fibrosis. Anat Rec (Hoboken) 2019; 303:608-618. [DOI: 10.1002/ar.24064] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/21/2018] [Accepted: 07/12/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Esperanza Bas
- Department of OtolaryngologyUniversity of Miami Ear Institute, University of Miami Miller School of Medicine Miami Florida 33136
| | - Mir R. Anwar
- Department of OtolaryngologyUniversity of Miami Ear Institute, University of Miami Miller School of Medicine Miami Florida 33136
| | - Thomas R. Van De Water
- Department of OtolaryngologyUniversity of Miami Ear Institute, University of Miami Miller School of Medicine Miami Florida 33136
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Lim HW, Pak K, Ryan AF, Kurabi A. Screening Mammalian Cochlear Hair Cells to Identify Critical Processes in Aminoglycoside-Mediated Damage. Front Cell Neurosci 2018; 12:179. [PMID: 30013464 PMCID: PMC6036173 DOI: 10.3389/fncel.2018.00179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/07/2018] [Indexed: 12/22/2022] Open
Abstract
There is considerable interest in discovering drugs with the potential to protect inner ear hair cells (HCs) from damage. One means of discovery is to screen compound libraries. Excellent screening protocols have been developed employing cell lines derived from the cochlea and zebrafish larvae. However, these do not address the differentiated mammalian hair cell. We have developed a screening method employing micro-explants of the mammalian organ of Corti (oC) to identify compounds with the ability to influence aminoglycoside-induced HC loss. The assay is based on short segments of the neonatal mouse oC, containing ~80 HCs which selectively express green fluorescent protein (GFP). This allows the screening of hundreds of potential protectants in an assay that includes both inner and outer HCs. This review article describes various screening methods, including the micro-explant assay. In addition, two micro-explant screening studies in which antioxidant and kinase inhibitor libraries were evaluated are reviewed. The results from these screens are related to current models of HC damage and protection.
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Affiliation(s)
- Hyun Woo Lim
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, United States.,Department of Otolaryngology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, South Korea
| | - Kwang Pak
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, United States.,San Diego VA Healthcare System, La Jolla, CA, United States
| | - Allen F Ryan
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, United States.,San Diego VA Healthcare System, La Jolla, CA, United States.,Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Arwa Kurabi
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, La Jolla, CA, United States
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Kasica N, Podlasz P, Sundvik M, Tamas A, Reglodi D, Kaleczyc J. Protective Effects of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Against Oxidative Stress in Zebrafish Hair Cells. Neurotox Res 2016; 30:633-647. [PMID: 27557978 PMCID: PMC5047952 DOI: 10.1007/s12640-016-9659-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/26/2016] [Accepted: 08/09/2016] [Indexed: 12/30/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide, with known antiapoptotic functions. Our previous in vitro study has demonstrated the ameliorative role of PACAP-38 in chicken hair cells under oxidative stress conditions, but its effects on living hair cells is now yet known. Therefore, the aim of the present study was to investigate in vivo the protective role of PACAP-38 in hair cells found in zebrafish (Danio rerio) sense organs-neuromasts. To induce oxidative stress the 5-day postfertilization (dpf) zebrafish larvae were exposed to 1.5 mM H2O2 for 15 min or 1 h. This resulted in an increase in caspase-3 and p-38 MAPK level in the hair cells as well as in an impairment of the larvae basic behavior. To investigate the ameliorative role of PACAP-38, the larvae were incubated with a mixture of 1.5 mM H2O2 and 100 nM PACAP-38 following 1 h preincubation with 100 nM PACAP-38 only. PACAP-38 abilities to prevent hair cells from apoptosis were investigated. Whole-mount immunohistochemistry and confocal microscopy analyses revealed that PACAP-38 treatment decreased the cleaved caspase-3 level in the hair cells, but had no influence on p-38 MAPK. The analyses of basic locomotor activity supported the protective role of PACAP-38 by demonstrating the improvement of the fish behavior after PACAP-38 treatment. In summary, our in vivo findings demonstrate that PACAP-38 protects zebrafish hair cells from oxidative stress by attenuating oxidative stress-induced apoptosis.
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Affiliation(s)
- Natalia Kasica
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, box 105J, 10-719, Olsztyn, Poland.
| | - Piotr Podlasz
- Department of Pathophysiology, Forensic Veterinary and Administration, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland
| | - Maria Sundvik
- Department of Anatomy, Neuroscience Center, University of Helsinki, Haartmaninkatu 8 (Biomedicum Helsinki), 00290, Helsinki, Finland
| | - Andrea Tamas
- Department of Anatomy, University of Pecs, Szigeti 12, 7624, Pecs, Hungary
| | - Dora Reglodi
- Department of Anatomy, University of Pecs, Szigeti 12, 7624, Pecs, Hungary
| | - Jerzy Kaleczyc
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, box 105J, 10-719, Olsztyn, Poland
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29
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Bas E, Bohorquez J, Goncalves S, Perez E, Dinh CT, Garnham C, Hessler R, Eshraghi AA, Van De Water TR. Electrode array-eluted dexamethasone protects against electrode insertion trauma induced hearing and hair cell losses, damage to neural elements, increases in impedance and fibrosis: A dose response study. Hear Res 2016; 337:12-24. [DOI: 10.1016/j.heares.2016.02.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/30/2015] [Accepted: 02/11/2016] [Indexed: 12/13/2022]
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30
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Tamames I, King C, Bas E, Dietrich WD, Telischi F, Rajguru SM. A cool approach to reducing electrode-induced trauma: Localized therapeutic hypothermia conserves residual hearing in cochlear implantation. Hear Res 2016; 339:32-9. [PMID: 27260269 DOI: 10.1016/j.heares.2016.05.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 05/19/2016] [Accepted: 05/26/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The trauma caused during cochlear implant insertion can lead to cell death and a loss of residual hair cells in the cochlea. Various therapeutic approaches have been studied to prevent cochlear implant-induced residual hearing loss with limited success. In the present study, we show the efficacy of mild to moderate therapeutic hypothermia of 4 to 6 °C applied to the cochlea in reducing residual hearing loss associated with the electrode insertion trauma. APPROACH Rats were randomly distributed in three groups: control contralateral cochleae, normothermic implanted cochleae and hypothermic implanted cochleae. Localized hypothermia was delivered to the middle turn of the cochlea for 20 min before and after implantation using a custom-designed probe perfused with cooled fluorocarbon. Auditory brainstem responses (ABRs) were recorded to assess the hearing function prior to and post-cochlear implantation at various time points up to 30 days. At the conclusion of the trials, inner ears were harvested for histology and cell count. The approach was extended to cadaver temporal bones to study the potential surgical approach and efficacy of our device. In this case, the hypothermia probe was placed next to the round window niche via the facial recess or a myringotomy. MAIN RESULTS A significant loss of residual hearing was observed in the normothermic implant group. Comparatively, the residual hearing in the cochleae receiving therapeutic hypothermia was significantly conserved. Histology confirmed a significant loss of outer hair cells in normothermic cochleae receiving the surgical trauma when compared to the hypothermia treated group. In human temporal bones, a controlled and effective cooling of the cochlea was achieved using our approach. SIGNIFICANCE Collectively, these results suggest that therapeutic hypothermia during cochlear implantation may reduce traumatic effects of electrode insertion and improve conservation of residual hearing.
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Affiliation(s)
- Ilmar Tamames
- Department of Biomedical Engineering, Seattle, WA, USA
| | | | - Esperanza Bas
- Department of Otolaryngology, University of Miami, Miami, FL, 33136, USA
| | - W Dalton Dietrich
- Department of Neurological Surgery, University of Miami, Miami, FL, 33136, USA
| | - Fred Telischi
- Department of Otolaryngology, University of Miami, Miami, FL, 33136, USA
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, Seattle, WA, USA; Department of Otolaryngology, University of Miami, Miami, FL, 33136, USA.
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Dexamethasone Protects Against Apoptotic Cell Death of Cisplatin-exposed Auditory Hair Cells In Vitro. Otol Neurotol 2016; 36:1566-71. [PMID: 26375980 DOI: 10.1097/mao.0000000000000849] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
HYPOTHESIS Dexamethasone (DXM) protects against cisplatin-induced auditory hair cell (HC) loss in rat organ of Corti (OC) explants in vitro by reducing levels of oxidative stress and NADPH-Oxidase-3 (NOX-3). BACKGROUND Intratympanic DXM has demonstrated protective effects against cisplatin-induced hearing loss in a few animal studies and one clinical trial. However, levels of protection with intratympanic DXM vary significantly between studies, which may not be a result of the intrinsic properties of DXM but rather reflect the diffusion of DXM into the cochlea. The molecular mechanisms and degree of DXM protection against cisplatin ototoxicity are currently unknown. METHODS OC explants from 3-day-old rats were cultured with no treatment or various concentrations of cisplatin (2, 5, or 10 μM) and DXM (75, 150, or 300 μg/mL) in vitro. HC viability and TUNEL assay were performed after 72 hours in vitro and levels of oxidative stress and NOX-3 were evaluated with confocal microscopy after 48 hours in vitro. Analysis of variance with Tukey's post hoc testing was performed. RESULTS Cisplatin initiated dose-dependent losses of outer HCs (OHCs) in the basal turns of exposed explants (p < 0.001). DXM protected against cisplatin (2 μM)-induced OHC loss in a dose-dependent manner with complete protection at 300 μg/mL of DXM (p < 0.001). DXM (150 μg/mL) significantly reduced levels of oxidative stress, NOX-3, and apoptosis in the basal turn of explants exposed to cisplatin (2 μM). CONCLUSIONS DXM protects against cisplatin-induced loss of OHCs in the basal turn of rat OC explants as demonstrated by reductions in oxidative stress and NOX-3 production and decreased levels of apoptotic cell death.
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Eshraghi AA, Roell J, Shaikh N, Telischi FF, Bauer B, Guardiola M, Bas E, Van De Water T, Rivera I, Mittal J. A novel combination of drug therapy to protect residual hearing post cochlear implant surgery. Acta Otolaryngol 2016; 136:420-4. [PMID: 26854005 DOI: 10.3109/00016489.2015.1134809] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
UNLABELLED Conclusions A cocktail combining NAC, Mannitol, and Dexamethasone may be used to prevent loss of residual hearing post-implantation. There is a window of opportunity to treat the cochlea before the onset of cell death in HCs. Objective Inner ear trauma caused by cochlear implant electrode insertion trauma (EIT) initiates multiple molecular mechanisms in hair cells (HCs) or support cells (SCs), resulting in initiation of programmed cell death within the damaged tissues of the cochlea, which leads to loss of residual hearing. In earlier studies L-N-acetylcysteine (L-NAC), Mannitol, and dexamethasone have been shown independently to protect the HCs loss against different types of inner ear trauma. These three molecules have different otoprotective effects. The goal of this preliminary study is to test the efficacy of a combination of these molecules to enhance the otoprotection of HCs against EIT. Methods OC explants were dissected from P-3 rats and placed in serum-free media. Explants were divided into control and experimental groups. CONTROL GROUP (1) untreated controls; (2) EIT. Experimental group: (1) EIT + L-NAC (5, 2, or 1 mM); (2) EIT + Mannitol (100, 50, or 10 mM); (3) EIT + Dex (20, 10, or 5 μg/mL); (4) EIT + L-NAC + Mannitol + Dex. After EIT was caused in an in-vitro model of CI, explants were cultured in media containing L-NAC alone, Mannitol alone, or Dex alone at decreasing concentrations. Concentrations of L-NAC, Mannitol, and Dex that showed 50% protection of hair cell loss individually were used as a combination in experimental group 4. Results There was an increase of total hair cell (THC) loss in the EIT OC explants when compared with control group HC counts or the tri-therapy cochlea. This study defined the dosage of L-NAC, Mannitol, and Dex for the survival of 50% protection of hair cells in vitro. Their combination provided close to 96% protection, demonstrating an additive effect.
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Affiliation(s)
- Adrien A Eshraghi
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Jonathan Roell
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Noah Shaikh
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Fred F Telischi
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Blake Bauer
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Mateo Guardiola
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Esperanza Bas
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Thomas Van De Water
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Ileana Rivera
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Jeenu Mittal
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
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Impedance Changes and Fibrous Tissue Growth after Cochlear Implantation Are Correlated and Can Be Reduced Using a Dexamethasone Eluting Electrode. PLoS One 2016; 11:e0147552. [PMID: 26840740 PMCID: PMC4739581 DOI: 10.1371/journal.pone.0147552] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/05/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The efficiency of cochlear implants (CIs) is affected by postoperative connective tissue growth around the electrode array. This tissue formation is thought to be the cause behind post-operative increases in impedance. Dexamethasone (DEX) eluting CIs may reduce fibrous tissue growth around the electrode array subsequently moderating elevations in impedance of the electrode contacts. METHODS For this study, DEX was incorporated into the silicone of the CI electrode arrays at 1% and 10% (w/w) concentration. Electrodes prepared by the same process but without dexamethasone served as controls. All electrodes were implanted into guinea pig cochleae though the round window membrane approach. Potential additive or synergistic effects of electrical stimulation (60 minutes) were investigated by measuring impedances before and after stimulation (days 0, 7, 28, 56 and 91). Acoustically evoked auditory brainstem responses were recorded before and after CI insertion as well as on experimental days 7, 28, 56, and 91. Additionally, histology performed on epoxy embedded samples enabled measurement of the area of scala tympani occupied with fibrous tissue. RESULTS In all experimental groups, the highest levels of fibrous tissue were detected in the basal region of the cochlea in vicinity to the round window niche. Both DEX concentrations, 10% and 1% (w/w), significantly reduced fibrosis around the electrode array of the CI. Following 3 months of implantation impedance levels in both DEX-eluting groups were significantly lower compared to the control group, the 10% group producing a greater effect. The same effects were observed before and after electrical stimulation. CONCLUSION To our knowledge, this is the first study to demonstrate a correlation between the extent of new tissue growth around the electrode and impedance changes after cochlear implantation. We conclude that DEX-eluting CIs are a means to reduce this tissue reaction and improve the functional benefits of the implant by attenuating electrode impedance.
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Jia H, François F, Bourien J, Eybalin M, Lloyd RV, Van De Water TR, Puel JL, Venail F. Prevention of trauma-induced cochlear fibrosis using intracochlear application of anti-inflammatory and antiproliferative drugs. Neuroscience 2015; 316:261-78. [PMID: 26718602 DOI: 10.1016/j.neuroscience.2015.12.031] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 12/14/2015] [Accepted: 12/16/2015] [Indexed: 12/20/2022]
Abstract
Cochlear fibrosis is a common finding following cochlear implantation. Evidence suggests that cochlear fibrosis could be triggered by inflammation and epithelial-to-mesenchymal cell transition (EMT). In this study, we investigate the mechanisms of cochlear fibrosis and the risk/benefit ratio of local administration of the anti-inflammatory drug dexamethasone (DEX) and antimitotic drug aracytine (Ara-C). Cochlear fibrosis was evaluated in cochlear fibrosis models of rat cochlear slices in vitro and in KLH-induced immune labyrinthitis and platinum wire cochlear implantation-induced fibrosis in vivo. Cochleae were invaded with tissue containing fibroblastic cells expressing α-SMA (alpha smooth muscle actin), which along with collagen I, fibronectin, and laminin in the extracellular matrix, suggests the involvement of a fibrotic process triggered by EMT in vitro and in vivo. After perilymphatic injection of an adenoviral vector expressing GFP in vivo, we demonstrated that the fibroblastic cells derived from the mesothelial cells of the scalae tympani and vestibuli. Activation of inflammatory and EMT pathways was further assessed by ELISA analysis of the expression of IL-1β and TGF-β1. Both markers were elevated in vitro and in vivo, and DEX and Ara-C were able to reduce IL-1β and TGF-β1 production. After 5days of culture in vitro, quantification of calcein-positive cells revealed that Ara-C was 30-fold more efficient in preventing fibrosis, and provoked less sensory hair cell loss, than DEX. In KLH-induced immune labyrinthitis and platinum wire-implanted models, Ara-C was more efficient in preventing proliferation of fibrosis with less side effects on hair cells and neurons than DEX. In conclusion, DEX and Ara-C both prevent fibrosis in the cochlea. Analysis of the risk/benefit ratio favors the use of Ara-C for preventing cochlear fibrosis.
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Affiliation(s)
- H Jia
- INSERM - UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; University Montpellier 1 & 2, Montpellier, France; Department of ORL H&N Surgery, Xinhua Hospital - Ear Institute, Shanghai Jiaotong University School of Medicine, China.
| | - F François
- INSERM - UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; University Montpellier 1 & 2, Montpellier, France.
| | - J Bourien
- INSERM - UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; University Montpellier 1 & 2, Montpellier, France.
| | - M Eybalin
- INSERM - UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; University Montpellier 1 & 2, Montpellier, France.
| | - R V Lloyd
- ENT Department, The Tunbridge Wells Hospital, Tunbridge Wells, UK.
| | - T R Van De Water
- Department of Otolaryngology, University of Miami Ear Institute, Miami, FL, USA.
| | - J-L Puel
- INSERM - UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; University Montpellier 1 & 2, Montpellier, France.
| | - F Venail
- INSERM - UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; University Montpellier 1 & 2, Montpellier, France; ENT Department, University Hospital Gui de Chauliac, Montpellier, France.
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Bas E, Goncalves S, Adams M, Dinh CT, Bas JM, Van De Water TR, Eshraghi AA. Spiral ganglion cells and macrophages initiate neuro-inflammation and scarring following cochlear implantation. Front Cell Neurosci 2015; 9:303. [PMID: 26321909 PMCID: PMC4532929 DOI: 10.3389/fncel.2015.00303] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 07/23/2015] [Indexed: 12/03/2022] Open
Abstract
Conservation of a patient's residual hearing and prevention of fibrous tissue/new bone formation around an electrode array are some of the major challenges in cochlear implant (CI) surgery. Although it is well-known that fibrotic tissue formation around the electrode array can interfere with hearing performance in implanted patients, and that associated intracochlear inflammation can initiate loss of residual hearing, little is known about the molecular and cellular mechanisms that promote this response in the cochlea. In vitro studies in neonatal rats and in vivo studies in adult mice were performed to gain insight into the pro-inflammatory, proliferative, and remodeling phases of pathological wound healing that occur in the cochlea following an electrode analog insertion. Resident Schwann cells (SC), macrophages, and fibroblasts had a prominent role in the inflammatory process in the cochlea. Leukocytes were recruited to the cochlea following insertion of a nylon filament in adult mice, where contributed to the inflammatory response. The reparative stages in wound healing are characterized by persistent neuro-inflammation of spiral ganglion neurons (SGN) and expression of regenerative monocytes/macrophages in the cochlea. Accordingly, genes involved in extracellular matrix (ECM) deposition and remodeling were up-regulated in implanted cochleae. Maturation of scar tissue occurs in the remodeling phase of wound healing in the cochlea. Similar to other damaged peripheral nerves, M2 macrophages and de-differentiated SC were observed in damaged cochleae and may play a role in cell survival and axonal regeneration. In conclusion, the insertion of an electrode analog into the cochlea is associated with robust early and chronic inflammatory responses characterized by recruitment of leukocytes and expression of pro-inflammatory cytokines that promote intracochlear fibrosis and loss of the auditory hair cells (HC) and SGN important for hearing after CI surgery.
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Affiliation(s)
- Esperanza Bas
- Department of Otolaryngology, Miller School of Medicine, University of Miami Miami, FL, USA
| | - Stefania Goncalves
- Department of Otolaryngology, Miller School of Medicine, University of Miami Miami, FL, USA
| | - Michelle Adams
- Department of Otolaryngology, Miller School of Medicine, University of Miami Miami, FL, USA
| | - Christine T Dinh
- Department of Otolaryngology, Miller School of Medicine, University of Miami Miami, FL, USA
| | - Jose M Bas
- Department of Otolaryngology, Miller School of Medicine, University of Miami Miami, FL, USA
| | - Thomas R Van De Water
- Department of Otolaryngology, Miller School of Medicine, University of Miami Miami, FL, USA
| | - Adrien A Eshraghi
- Department of Otolaryngology, Miller School of Medicine, University of Miami Miami, FL, USA
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Ihler F, Pelz S, Coors M, Matthias C, Canis M. Application of a TNF-alpha-inhibitor into the scala tympany after cochlear electrode insertion trauma in guinea pigs: preliminary audiologic results. Int J Audiol 2015; 53:810-6. [PMID: 25311100 DOI: 10.3109/14992027.2014.938369] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Cochlear implantation trauma causes both macroscopic and inflammatory trauma. The aim of the present study was to evaluate the effectiveness of the TNF-alpha inhibitor etanercept applied after cochlear implantation trauma on the preservation of acoustic hearing. DESIGN Guinea pigs were randomly assigned to three groups receiving cochlear implantation trauma by cochleostomy. In one group, the site was sealed by bone cement with no further treatment. A second group was additionally implanted with an osmotic minipump delivering artificial perilymph into the scala tympani for seven days. In the third group, etanercept 1 mg/ml was added to artificial perilymph. Hearing was assessed by auditory brainstem responses at 2, 4, 6, and 8 kHz prior to and after surgery and on days 3, 5, 7, 14, 28. STUDY SAMPLE Fifteen healthy guinea pigs. RESULTS The trauma led to threshold shifts from 50.3 dB ± 16.3 dB to 68.0 dB ± 19.3 dB. Hearing thresholds were significantly lower in etanercept-treated animals compared to controls on day 28 at 8 kHz and from day 3 onwards at 4 and 2 kHz (p < 0.01; two-way RM ANOVA / Bonferroni t-test). CONCLUSION The application of etanercept led to preservation of acoustic hearing after cochlear implantation trauma.
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Affiliation(s)
- Friedrich Ihler
- * Department of Otorhinolaryngology, University Medical Center Göttingen , Germany
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Liu Y, Jolly C, Braun S, Janssen T, Scherer E, Steinhoff J, Ebenhoch H, Lohner A, Stark T, Kiefer J. Effects of a dexamethasone-releasing implant on cochleae: A functional, morphological and pharmacokinetic study. Hear Res 2015; 327:89-101. [PMID: 25987502 DOI: 10.1016/j.heares.2015.04.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 04/22/2015] [Accepted: 04/24/2015] [Indexed: 01/12/2023]
Abstract
AIM This study evaluated the impact of a dexamethasone-releasing silicone implant on hearing function preservation, cochlear morphology and perilymph pharmacokinetics after cochlear implantation. METHODS Guinea pigs were implanted unilaterally with silicone rods containing either 2% dexamethasone (DEXA group, n = 18) or no dexamethasone (control group, n = 17). Auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs) were measured preoperatively and over 6 months postoperatively. Cochlear histology using standard hematoxylin and eosin (H&E) staining and tumor necrosis factor (TNF)-alpha staining was performed 1 month postoperatively. Twenty-two guinea pigs were involved in the pharmacokinetic study, and real-time drug concentrations in perilymph were investigated using high-performance liquid chromatography (HPLC). The Mann-Whitney U test (1-tailed) was used for statistical analyses. RESULTS ABR and DPOAE testing demonstrated decreased hearing function immediately postoperatively followed by a progressive hearing loss within the first day postoperatively. There was almost no observable hearing improvement in the control group from 1 week to 6 months postoperatively, but hearing levels in the DEXA group improved gradually from 1 week to 12 weeks. Hearing loss in the DEXA and control group was 5.0 ± 3.4 dB and 21.7 ± 5.3 dB, respectively at a 16-kHz stimulus frequency 6 months postoperatively. The difference in threshold shifts was present throughout all measured frequencies, and it was significant at 4-24 kHz. The morphological study revealed new fibrosis formation in the scala tympani, which encapsulated the implanted electrode. TNF-alpha positive staining in the cochleae of the DEXA group was less evident than the control group. The pharmacokinetic study revealed a peak perilymph concentration 30 min postoperatively and sustained dexamethasone release at least 1 week postoperatively. CONCLUSION Cochlear implants that incorporate dexamethasone can release drug chronically in the inner ear and induce significant long-term recovery and preservation of auditory function after implantation.
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Affiliation(s)
- Ya Liu
- Department of Otolaryngology-Head and Neck Surgery, Beijing Naval General Hospital, Beijing 100048, PR China
| | - Claude Jolly
- Electrode Research Section, MED-EL Medical Electronics, Innsbruck, Austria
| | | | - Thomas Janssen
- Clinic for Otorhinolaryngology, Head- and Neck Surgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Elias Scherer
- Clinic for Otorhinolaryngology, Head- and Neck Surgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jochen Steinhoff
- Clinic for Otorhinolaryngology, Head- and Neck Surgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Harald Ebenhoch
- Clinic for Otorhinolaryngology, Head- and Neck Surgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Andrea Lohner
- Clinic for Otorhinolaryngology, Head- and Neck Surgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Thomas Stark
- Clinic for Otorhinolaryngology, Head- and Neck Surgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jan Kiefer
- HNO-Zentrum Neupfarrplatz, 12/II, 93047 Regensburg, Germany.
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Dinh CT, Goncalves S, Bas E, Van De Water TR, Zine A. Molecular regulation of auditory hair cell death and approaches to protect sensory receptor cells and/or stimulate repair following acoustic trauma. Front Cell Neurosci 2015; 9:96. [PMID: 25873860 PMCID: PMC4379916 DOI: 10.3389/fncel.2015.00096] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 03/03/2015] [Indexed: 12/20/2022] Open
Abstract
Loss of auditory sensory hair cells (HCs) is the most common cause of hearing loss. This review addresses the signaling pathways that are involved in the programmed and necrotic cell death of auditory HCs that occur in response to ototoxic and traumatic stressor events. The roles of inflammatory processes, oxidative stress, mitochondrial damage, cell death receptors, members of the mitogen-activated protein kinase (MAPK) signal pathway and pro- and anti-cell death members of the Bcl-2 family are explored. The molecular interaction of these signal pathways that initiates the loss of auditory HCs following acoustic trauma is covered and possible therapeutic interventions that may protect these sensory HCs from loss via apoptotic or non-apoptotic cell death are explored.
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Affiliation(s)
- Christine T Dinh
- University of Miami Ear Institute, University of Miami Miller School of Medicine Miami, FL, USA
| | - Stefania Goncalves
- University of Miami Ear Institute, University of Miami Miller School of Medicine Miami, FL, USA
| | - Esperanza Bas
- University of Miami Ear Institute, University of Miami Miller School of Medicine Miami, FL, USA
| | - Thomas R Van De Water
- University of Miami Ear Institute, University of Miami Miller School of Medicine Miami, FL, USA
| | - Azel Zine
- Integrative and Adaptive Neurosciences, Aix-Marseille Université, CNRS, UMR 7260 Marseille, France ; Faculty of Pharmacy, Biophysics Department, University of Montpellier Montpellier, France
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Lumbreras V, Bas E, Gupta C, Rajguru SM. Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling. J Neurophysiol 2014; 112:1246-55. [PMID: 24920028 DOI: 10.1152/jn.00253.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca(2+) imaging. Both types of neurons responded consistently with robust intracellular Ca(2+) ([Ca(2+)]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25-1 pps). Radiant exposures of ∼637 mJ/cm(2) resulted in continual neuronal activation. Temperature or [Ca(2+)] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca(2+) involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na(+), K(+), and Ca(2+) plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca(2+) cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca(2+)]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca(2+) release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses.
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Affiliation(s)
- Vicente Lumbreras
- Department of Biomedical Engineering, University of Miami, Miami, Florida; and
| | - Esperanza Bas
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - Chhavi Gupta
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Miami, Florida; and Department of Otolaryngology, University of Miami, Miami, Florida
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Gross J, Olze H, Mazurek B. Differential Expression of Transcription Factors and Inflammation-, ROS-, and Cell Death-Related Genes in Organotypic Cultures in the Modiolus, the Organ of Corti and the Stria Vascularis of Newborn Rats. Cell Mol Neurobiol 2014; 34:523-38. [DOI: 10.1007/s10571-014-0036-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 02/14/2014] [Indexed: 12/22/2022]
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Lee J, Ismail H, Lee JH, Kel G, O'Leary J, Hampson A, Eastwood H, O'Leary SJ. Effect of Both Local and Systemically Administered Dexamethasone on Long-Term Hearing and Tissue Response in a Guinea Pig Model of Cochlear Implantation. ACTA ACUST UNITED AC 2013; 18:392-405. [DOI: 10.1159/000353582] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 06/06/2013] [Indexed: 12/13/2022]
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Van De Water TR. Historical Aspects of Inner Ear Anatomy and Biology that Underlie the Design of Hearing and Balance Prosthetic Devices. Anat Rec (Hoboken) 2012; 295:1741-59. [PMID: 23045252 DOI: 10.1002/ar.22598] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 07/24/2012] [Indexed: 12/19/2022]
Abstract
This review presents some of the major historical events that advanced the body of knowledge of the anatomy of the inner ear and its sensory receptors as well as the biology of these receptors that underlies the sensory functions of hearing and balance. This knowledge base of the inner ear's structure/function has been an essential factor for the design and construction of prosthetic devices to aid patients with deficits in their senses of hearing and balance. Prosthetic devices are now available for severely hearing impaired and deaf patients to restore hearing and are known as cochlear implants and auditory brain stem implants. A prosthetic device for patients with balance disorders is being perfected and is in an animal model testing phase with another prosthetic device for controlling intractable dizziness in Meniere's patients currently being evaluated in clinical testing. None of this would have been possible without the pioneering studies and discoveries of the investigators mentioned in this review and with the work of many other talented investigators to numerous to be covered in this review.
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Affiliation(s)
- Thomas R Van De Water
- Cochlear Implant Research Program, University of Miami Ear Institute, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida 33136-1015, USA.
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