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Rahman MT, Mostaert B, Eckard P, Fatima SM, Scheperle R, Razu I, Hunger B, Olszewski RT, Gu S, Garcia C, Khan NA, Bennion DM, Oleson J, Kirk JR, Enke YL, Gay RD, Morell RJ, Hirose K, Hoa M, Claussen AD, Hansen MR. Cochlear implants with dexamethasone-eluting electrode arrays reduce foreign body response in a murine model of cochlear implantation and human subjects. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.10.11.24315311. [PMID: 39417118 PMCID: PMC11483020 DOI: 10.1101/2024.10.11.24315311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
The inflammatory foreign body response (FBR) following cochlear implantation (CI) can negatively impact CI outcomes, including increased electrode impedances. This study aims to investigate the long-term efficacy of dexamethasone eluting cochlear implant and locally delivered dexamethasone, a potent anti-inflammatory glucocorticoid on the intracochlear FBR and electrical impedance post-implantation in a murine model and human subjects. The left ears of CX3CR1 +/GFP Thy1 +/YFP (macrophage-neuron dual reporter) mice were implanted with dexamethasone-eluting cochlear implants (Dex-CI) or standard implant (Standard-CI) while the right ear served as unoperated control. Another group of dual reporter mice was implanted with a standard CI electrode array followed by injection of dexamethasone in the middle ear to mimic current clinical practice (Dex-local). Mouse implants were electrically stimulated with serial measurement of electrical impedance. Human subjects were implanted with either standard or Dex-CI followed by serial impedance measurements. Dex-CI reduced electrical impedance in the murine model and human subjects and inflammatory FBR in the murine model for an extended period. Dex-local in the murine model is ineffective for long-term reduction of FBR and electrode impedance. Our data suggest that dexamethasone eluting arrays are more effective than the current clinical practice of locally applied dexamethasone in reducing FBR and electrical impedance.
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Carles L, Gibaja A, Scheper V, Alvarado JC, Almodovar C, Lenarz T, Juiz JM. Efficacy and Mechanisms of Antioxidant Compounds and Combinations Thereof against Cisplatin-Induced Hearing Loss in a Rat Model. Antioxidants (Basel) 2024; 13:761. [PMID: 39061830 PMCID: PMC11273477 DOI: 10.3390/antiox13070761] [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: 05/13/2024] [Revised: 06/13/2024] [Accepted: 06/19/2024] [Indexed: 07/28/2024] Open
Abstract
Cisplatin is an election chemotherapeutic agent used for many cancer treatments. Its cytotoxicity against neoplastic cells is mirrored by that taking place in healthy cells and tissues, resulting in serious adverse events. A very frequent one is ototoxicity, causing hearing loss which may permanently affect quality of life after successful oncologic treatments. Exacerbated oxidative stress is a main cytotoxic mechanism of cisplatin, including ototoxicity. Previous reports have shown antioxidant protection against cisplatin ototoxicity, but there is a lack of comparative studies on the otoprotectant activity and mechanism of antioxidant formulations. Here, we show evidence that a cocktail of vitamins A, C, and E along with Mg++ (ACEMg), previously shown to protect against noise-induced hearing loss, reverses auditory threshold shifts, promotes outer hair cell survival, and attenuates oxidative stress in the cochlea after cisplatin treatment, thus protecting against extreme cisplatin ototoxicity in rats. The addition of 500 mg N-acetylcysteine (NAC), which, administered individually, also shows significant attenuation of cisplatin ototoxicity, to the ACEMg formulation results in functional degradation of ACEMg otoprotection. Mg++ administered alone, as MgSO4, also prevents cisplatin ototoxicity, but in combination with 500 mg NAC, otoprotection is also greatly degraded. Increasing the dose of NAC to 1000 mg also results in dramatic loss of otoprotection activity compared with 500 mg NAC. These findings support that single antioxidants or antioxidant combinations, particularly ACEMg in this experimental series, have significant otoprotection efficacy against cisplatin ototoxicity. However, an excess of combined antioxidants and/or elevated doses, above a yet-to-be-defined "antioxidation threshold", results in unrecoverable redox imbalance with loss of otoprotectant activity.
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Grants
- PID2020-117266RB-C22-1, EXC 2177/1, ID:390895286, SBPLY/17/180501/000544. Ministerio de Ciencia Innovación, MCINN, Gobierno de España, Plan Estatal de I+D+i, PID2020-117266RB-C22-1, Cluster of Excellence "Hearing4All" EXC 2177/1, ID:390895286, part of the Germany´s Excellence Strategy of the German Research Foundation, DFG. Co
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Affiliation(s)
- Liliana Carles
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008 Albacete, Spain; (L.C.); (A.G.); (J.C.A.)
- Department of Otolaryngology, University Hospital “Doce de Octubre”, 28041 Madrid, Spain;
| | - Alejandro Gibaja
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008 Albacete, Spain; (L.C.); (A.G.); (J.C.A.)
| | - Verena Scheper
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (V.S.); (T.L.)
- Cluster of Excellence “Hearing4all” of the German Research Foundation, DFG, 26111 Oldenburg, Germany
| | - Juan C. Alvarado
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008 Albacete, Spain; (L.C.); (A.G.); (J.C.A.)
| | - Carlos Almodovar
- Department of Otolaryngology, University Hospital “Doce de Octubre”, 28041 Madrid, Spain;
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (V.S.); (T.L.)
- Cluster of Excellence “Hearing4all” of the German Research Foundation, DFG, 26111 Oldenburg, Germany
| | - José M. Juiz
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008 Albacete, Spain; (L.C.); (A.G.); (J.C.A.)
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (V.S.); (T.L.)
- Cluster of Excellence “Hearing4all” of the German Research Foundation, DFG, 26111 Oldenburg, Germany
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Le Prell CG, Clavier OH, Bao J. Noise-induced hearing disorders: Clinical and investigational tools. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:711. [PMID: 36732240 PMCID: PMC9889121 DOI: 10.1121/10.0017002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
A series of articles discussing advanced diagnostics that can be used to assess noise injury and associated noise-induced hearing disorders (NIHD) was developed under the umbrella of the United States Department of Defense Hearing Center of Excellence Pharmaceutical Interventions for Hearing Loss working group. The overarching goals of the current series were to provide insight into (1) well-established and more recently developed metrics that are sensitive for detection of cochlear pathology or diagnosis of NIHD, and (2) the tools that are available for characterizing individual noise hazard as personal exposure will vary based on distance to the sound source and placement of hearing protection devices. In addition to discussing the utility of advanced diagnostics in patient care settings, the current articles discuss the selection of outcomes and end points that can be considered for use in clinical trials investigating hearing loss prevention and hearing rehabilitation.
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Affiliation(s)
- Colleen G Le Prell
- Department of Speech, Language, and Hearing Science, University of Texas at Dallas, Richardson, Texas 75080, USA
| | | | - Jianxin Bao
- Gateway Biotechnology Inc., St. Louis, Missouri 63132, USA
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Gantz BJ, Hansen M, Dunn CC. Clinical perspective on hearing preservation in cochlear implantation, the University of Iowa experience. Hear Res 2022; 426:108487. [PMID: 35410721 PMCID: PMC9482999 DOI: 10.1016/j.heares.2022.108487] [Citation(s) in RCA: 8] [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: 10/29/2021] [Revised: 02/17/2022] [Accepted: 03/15/2022] [Indexed: 12/16/2022]
Abstract
Preservation of residual acoustic hearing has emerged as an important concept for those individuals undergoing cochlear implantation with residual low frequency hearing. Acoustic plus electric speech processing improves hearing outcomes in quiet, enables melody recognition, preserves spatial hearing if there is acoustic hearing in both ears and significantly improves hearing in noise. The development of our experience with acoustic plus electric processing is reviewed along with clinical trials and patient outcomes that our team has documented over the past twenty years.
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Affiliation(s)
- Bruce J Gantz
- The University of Iowa Cochlear Implant Clinical Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, IA United States.
| | - Marlan Hansen
- The University of Iowa Cochlear Implant Clinical Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, IA United States
| | - Camille C Dunn
- The University of Iowa Cochlear Implant Clinical Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, IA United States
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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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Rai N, Kanagaraj S. Enhanced Antioxidant Ability of PEG-Coated Ce 0.5Zr 0.5O 2-Based Nanofluids for Scavenging Hydroxyl Radicals. ACS OMEGA 2022; 7:22363-22376. [PMID: 35811870 PMCID: PMC9260909 DOI: 10.1021/acsomega.2c01266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
The antioxidant therapy to preserve residual hearing is relatively recent, and the search for effective antioxidants is still ongoing. Though nanoceria has shown promising radical-scavenging capability, improving its antioxidant ability and the dispersion stability of its nanofluid, which is critical to the desired site, i.e., cochlea, still remains a major challenge. The objective of the present work is to study the radical-scavenging capability of poly(ethylene glycol) (PEG)-coated CeO2 and Ce0.5Zr0.5O2 nanoparticles in water and the biologically relevant fluid (PBS buffer). Nanoparticles in the size range of 4.0-9.0 nm are synthesized using the coprecipitation method and characterized using suitable techniques. The scavenging and dispersion stability of the synthesized nanofluid are analyzed using a UV-vis spectrophotometer. It is found that the addition of PEG during the synthesis process promoted the generation of finer nanoparticles with a narrow size distribution and the doping of zirconium produced a large number of defects in the crystallite structure. The PEG coating over the nanoparticles improved the dispersion stability of nanofluids without affecting their surface reactivity, and it is found to be 94 and 80% in water and PBS, respectively, at 500 μM and 60 min, which is maintained till 90 min. The highest scavenging of hydroxyl radicals by PEG-coated Ce0.5Zr0.5O2 is found to be 60%, which is significantly superior to that of CeO2. The scavenging capability is found to be increased with the concentration of nanoparticles, showing the best scavenging activity at 190 and 150 μM for PEG-coated CeO2 and Ce0.5Zr0.5O2, respectively, and the scavenging in water is at par with that of PBS, indicating that these nanoparticles are suitable to be used in sites where a biologically relevant fluid is present, e.g., the cochlea. It is proposed that PEG-coated Ce0.5Zr0.5O2 having an average size of ∼ 4 nm can be a potential antioxidant in relevant biomedical applications.
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Gärtner L, Klötzer K, Lenarz T, Scheper V. Correlation of Electrically Evoked Compound Action Potential Amplitude Growth Function Slope and Anamnestic Parameters in Cochlear Implant Patients-Identification of Predictors for the Neuronal Health Status. Life (Basel) 2021; 11:life11030203. [PMID: 33807687 PMCID: PMC7999542 DOI: 10.3390/life11030203] [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: 02/01/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 01/04/2023] Open
Abstract
Cochlear implants (CI) are the treatment of choice in profoundly deaf patients. Measuring the electrically evoked compound action potential (ECAP) has become an important tool for verifying the function of the spiral ganglion neurons (SGN), which are the target cells of the CI stimulation. ECAP measurement is only possible after electrode insertion. No information about the neuronal health status is available before cochlear implantation. We investigated possible correlations between the ECAP amplitude growth function (AGF) slope and anamnestic parameters to identify possible predictors for SGN health status and therefore for CI outcome. The study included patients being implanted with various electrode array lengths. Correlation analysis was performed for the mean AGF slope of the whole array, for separate electrodes as well as for grouped electrodes of the apical, medial, and basal region, with duration of deafness, age at implantation, residual hearing (grouped for electrode length), and etiology. The mean ECAP AGF slopes decreased from apical to basal. They were not correlated to the length of the electrode array or any etiology. For the mean of the full array or when grouped for the apical, middle, and basal part, the ECAP AGF slope was negatively correlated to the duration of hearing loss and the age at implantation. Since a significant negative correlation of the ECAP AGF slope and age at cochlear implantation and duration of deafness was observed, this study supports the statement that early implantation of a CI is recommended for sensorineural hearing loss. Additional factors such as the cochlear coverage and insertion angle influence the ECAP AGF slope and performance of the patient and should be included in future multifactorial analysis to study predictive parameters for the CI outcome.
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Affiliation(s)
- Lutz Gärtner
- Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany; (L.G.); (K.K.); (T.L.)
| | - Katharina Klötzer
- Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany; (L.G.); (K.K.); (T.L.)
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany; (L.G.); (K.K.); (T.L.)
- Cluster of Excellence “Hearing4All”, 30625 Hannover, Germany
| | - Verena Scheper
- Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany; (L.G.); (K.K.); (T.L.)
- Cluster of Excellence “Hearing4All”, 30625 Hannover, Germany
- Correspondence: ; Tel.: +49-511-532-4369
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Hochmair I. Translational research around five categories of CI. Acta Otolaryngol 2021; 141:178-184. [PMID: 33818266 DOI: 10.1080/00016489.2021.1888516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Five categories of cochlear implants are introduced: The 'classic CI', the 'combined CI' - which can be combining a CI based on electric stimulation with acoustic stimulation (EAS) or with mechanical stimulation (EMS) or with electrical stimulation of the vestibular system (VICI) -, the 'individualised CI', the 'augmented CI' and the 'totally implantable CI'. The translational research activities leading to and within these categories have been, are and will be numerous and are the subject of the compendium for which this paper is the concluding chapter. Early translational research has resulted in the 'classic CI' in 1994. From then on translational research enabled the developments respectively the new indications and reimbursement of CI-systems for bilateral CIs, CI in single sided deafness, the auditory brainstem implant, speech coding and signal processing advances, electrophysiologic measurements for evaluation of cochlear health, all within the classic CI category. Starting points for the four newer categories of CI are either ideas of professionals treating hearing loss or of CI developers. The translational research performed also triggered research that led and leads to improved understanding of the fundamental mechanisms of hearing.
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Affiliation(s)
- Ingeborg Hochmair
- MED-EL Elektromedizinische Geraete Gesellschaft m.b.H., Innsbruck, Austria
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Abstract
Intra-cochlear fibrous tissue formation around the electrode following cochlear implantation affects the electrode impedance as well as electrode explantation during reimplantation surgeries. Applying corticosteroids in cochlear implantation is one way of minimizing the intra-cochlear fibrous tissue formation around the electrode. It were J. Kiefer, C. von Ilberg, and W. Gstöttner who proposed the first idea on drug delivery application in cochlear implantation to MED-EL in the year 2000. During the twenty years of translational research efforts at MED-EL in collaboration with several clinics and research institutions from across the world, preclinical safety and efficacy of corticosteroids were performed leading to the final formulation of the electrode design. In parallel to the drug eluting CI electrode development, MED-EL also invested research efforts into developing tools enabling delivery of pharmaceutical agents of surgeon's choice inside the cochlea. The inner ear catheter designed to administer drug substances into the cochlea was CE marked in 2020. A feasibility study in human subjects with MED-EL CI featuring dexamethasone-eluting electrode array started in June 2020. This article covers the milestones of translational research towards the drug delivery in CI application that took place in association with MED-EL.
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Affiliation(s)
| | - Ingeborg Hochmair
- MED-EL Elektromedizinische Geraete Gesellschaft m.b.H., Innsbruck, Austria
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