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Jeong MY, Kim S, Kim HR, Jeon J, Won SS, Yang KJ, Park JS, Yang IG, Lee DG, Myung JH, Kim YG, Jin SG, Choi YS, Kim DK, Kang MJ. Dexamethasone nanocrystals-embedded hydroxypropyl methylcellulose hydrogel increases cochlear delivery and attenuates hearing loss following intratympanic injection. Carbohydr Polym 2024; 345:122546. [PMID: 39227091 DOI: 10.1016/j.carbpol.2024.122546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 07/09/2024] [Accepted: 07/24/2024] [Indexed: 09/05/2024]
Abstract
Herein, dexamethasone (DEX) nanocrystalline suspension (NS)-embedded hydrogel (NS-G) was constructed using a hydroxypropyl methylcellulose (HPMC) polymer to enhance cochlear delivery and attenuate hearing loss following intratympanic (IT) injection. Hydrophobic steroidal nanocrystals were prepared using a bead milling technique and incorporated into a polysaccharide hydrogel. The NS-G system with HPMC (average molecular weight, 86,000 g/mol; 15 mg/mL) was characterized as follows: rod-shaped drug crystalline; particle size <300 nm; and constant complex viscosity ≤1.17 Pa·s. Pulverization of the drug particles into submicron diameters enhanced drug dissolution, while the HPMC matrix increased the residence time in the middle ear cavity, exhibiting a controlled release profile. The IT NS-G system elicited markedly enhanced and prolonged drug delivery (> 9 h) to the cochlear tissue compared with that of DEX sodium phosphate (DEX-SP), a water-soluble prodrug. In mice with kanamycin- and furosemide-induced ototoxicity, NS-G markedly enhanced hearing preservation across all frequencies (8-32 kHz), as revealed by an auditory brainstem response test, compared with both saline and DEX-SP. Moreover, treatment with NS-G showed enhanced anti-inflammatory effects, as evidenced by decreased levels of inflammation-related cytokines. Therefore, the IT administration of DEX NS-loaded HPMC hydrogels is a promising strategy for treating hearing loss.
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Affiliation(s)
- Min Young Jeong
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - Subin Kim
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea. 64 Daeheung-ro, Jung-gu, Daejeon, 34943, Republic of Korea
| | - Hye Rim Kim
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - Jiae Jeon
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea. 64 Daeheung-ro, Jung-gu, Daejeon, 34943, Republic of Korea
| | - Seong Su Won
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea. 64 Daeheung-ro, Jung-gu, Daejeon, 34943, Republic of Korea
| | - Keum-Jin Yang
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea. 64 Daeheung-ro, Jung-gu, Daejeon, 34943, Republic of Korea
| | - Jun Soo Park
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - In Gyu Yang
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - Dong Geon Lee
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - Jin Hyuk Myung
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - Yoon-Gyoon Kim
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - Sung Giu Jin
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - Yong Seok Choi
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea
| | - Dong-Kee Kim
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea. 64 Daeheung-ro, Jung-gu, Daejeon, 34943, Republic of Korea.
| | - Myung Joo Kang
- College of Pharmacy, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan, Chungnam 31116, Republic of Korea.
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Vecchi JT, Claussen AD, Hansen MR. Decreasing the physical gap in the neural-electrode interface and related concepts to improve cochlear implant performance. Front Neurosci 2024; 18:1425226. [PMID: 39114486 PMCID: PMC11303154 DOI: 10.3389/fnins.2024.1425226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/11/2024] [Indexed: 08/10/2024] Open
Abstract
Cochlear implants (CI) represent incredible devices that restore hearing perception for those with moderate to profound sensorineural hearing loss. However, the ability of a CI to restore complex auditory function is limited by the number of perceptually independent spectral channels provided. A major contributor to this limitation is the physical gap between the CI electrodes and the target spiral ganglion neurons (SGNs). In order for CI electrodes to stimulate SGNs more precisely, and thus better approximate natural hearing, new methodologies need to be developed to decrease this gap, (i.e., transitioning CIs from a far-field to near-field device). In this review, strategies aimed at improving the neural-electrode interface are discussed in terms of the magnitude of impact they could have and the work needed to implement them. Ongoing research suggests current clinical efforts to limit the CI-related immune response holds great potential for improving device performance. This could eradicate the dense, fibrous capsule surrounding the electrode and enhance preservation of natural cochlear architecture, including SGNs. In the long term, however, optimized future devices will likely need to induce and guide the outgrowth of the peripheral process of SGNs to be in closer proximity to the CI electrode in order to better approximate natural hearing. This research is in its infancy; it remains to be seen which strategies (surface patterning, small molecule release, hydrogel coating, etc.) will be enable this approach. Additionally, these efforts aimed at optimizing CI function will likely translate to other neural prostheses, which face similar issues.
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Affiliation(s)
- Joseph T. Vecchi
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, Iowa City, IA, United States
- Department of Otolaryngology Head-Neck Surgery, Carver College of Medicine, Iowa City, IA, United States
| | - Alexander D. Claussen
- Department of Otolaryngology Head-Neck Surgery, Carver College of Medicine, Iowa City, IA, United States
| | - Marlan R. Hansen
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, Iowa City, IA, United States
- Department of Otolaryngology Head-Neck Surgery, Carver College of Medicine, Iowa City, IA, United States
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3
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Khurana L, Harczos T, Moser T, Jablonski L. En route to sound coding strategies for optical cochlear implants. iScience 2023; 26:107725. [PMID: 37720089 PMCID: PMC10502376 DOI: 10.1016/j.isci.2023.107725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023] Open
Abstract
Hearing loss is the most common human sensory deficit. Severe-to-complete sensorineural hearing loss is often treated by electrical cochlear implants (eCIs) bypassing dysfunctional or lost hair cells by direct stimulation of the auditory nerve. The wide current spread from each intracochlear electrode array contact activates large sets of tonotopically organized neurons limiting spectral selectivity of sound coding. Despite many efforts, an increase in the number of independent eCI stimulation channels seems impossible to achieve. Light, which can be better confined in space than electric current may help optical cochlear implants (oCIs) to overcome eCI shortcomings. In this review, we present the current state of the optogenetic sound encoding. We highlight optical sound coding strategy development capitalizing on the optical stimulation that requires fine-grained, fast, and power-efficient real-time sound processing controlling dozens of microscale optical emitters as an emerging research area.
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Affiliation(s)
- Lakshay Khurana
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- Auditory Neuroscience and Synaptic Nanophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Junior Research Group “Computational Neuroscience and Neuroengineering”, Göttingen, Germany
- The Doctoral Program “Sensory and Motor Neuroscience”, Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences (GGNB), Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tamas Harczos
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- Auditory Neuroscience and Synaptic Nanophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Lukasz Jablonski
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- Junior Research Group “Computational Neuroscience and Neuroengineering”, Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
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Delaney DS, Liew LJ, Lye J, Atlas MD, Wong EYM. Overcoming barriers: a review on innovations in drug delivery to the middle and inner ear. Front Pharmacol 2023; 14:1207141. [PMID: 37927600 PMCID: PMC10620978 DOI: 10.3389/fphar.2023.1207141] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 10/02/2023] [Indexed: 11/07/2023] Open
Abstract
Despite significant advances in the development of therapeutics for hearing loss, drug delivery to the middle and inner ear remains a challenge. As conventional oral or intravascular administration are ineffective due to poor bioavailability and impermeability of the blood-labyrinth-barrier, localized delivery is becoming a preferable approach for certain drugs. Even then, localized delivery to the ear precludes continual drug delivery due to the invasive and potentially traumatic procedures required to access the middle and inner ear. To address this, the preclinical development of controlled release therapeutics and drug delivery devices have greatly advanced, with some now showing promise clinically. This review will discuss the existing challenges in drug development for treating the most prevalent and damaging hearing disorders, in particular otitis media, perforation of the tympanic membrane, cholesteatoma and sensorineural hearing loss. We will then address novel developments in drug delivery that address these including novel controlled release therapeutics such as hydrogel and nanotechnology and finally, novel device delivery approaches such as microfluidic systems and cochlear prosthesis-mediated delivery. The aim of this review is to investigate how drugs can reach the middle and inner ear more efficiently and how recent innovations could be applied in aiding drug delivery in certain pathologic contexts.
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Affiliation(s)
- Derek S. Delaney
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
- Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA, Australia
| | - Lawrence J. Liew
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA, Australia
| | - Joey Lye
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
| | - Marcus D. Atlas
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA, Australia
- Faculty of Health Sciences, Curtin Medical School, Curtin University, Bentley, WA, Australia
| | - Elaine Y. M. Wong
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA, Australia
- Faculty of Health Sciences, Curtin Medical School, Curtin University, Bentley, WA, Australia
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Lehner E, Honeder C, Knolle W, Binder W, Scheffler J, Plontke SK, Liebau A, Mäder K. Towards the optimization of drug delivery to the cochlear apex: Influence of polymer and drug selection in biodegradable intracochlear implants. Int J Pharm 2023; 643:123268. [PMID: 37488058 DOI: 10.1016/j.ijpharm.2023.123268] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 07/26/2023]
Abstract
There is growing need for new drug delivery systems for intracochlear application of drugs to effectively treat inner ear disorders. In this study, we describe the development and characterization of biodegradable, triamcinolone-loaded implants based on poly(lactic-co-glycolic acid) (PLGA) and polyethylene glycol-poly(lactic-co-glycolic acid) (PEG-PLGA) respectively, prepared by hot-melt extrusion. PEG 1500 was used as a plasticizer to improve flexibility and accelerate drug release. The sterilization process was performed by electron beam irradiation, resulting in minimal but acceptable polymer degradation for PEG-PLGA implants. The implants have been characterized by texture analysis, differential scanning calorimetry and X-ray powder diffraction. Compared to PLGA implants, PEG-PLGA implants offer similar flexibility but with improved mechanical stability, which will ease the handling and intracochlear application. A controlled release over three months was observed for dexamethasone and triamcinolone extrudates (drug load of 10%) with similar release profiles for both drugs. PEG-PLGA implants showed an initial slow release rate over several days regardless of the amount of PEG added. Mathematical simulations of the pharmacokinetics of the inner ear based on the in vitro release kinetics indicate a complete distribution of triamcinolone in the whole human scala tympani, which underlines the high potential of the developed formulation.
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Affiliation(s)
- E Lehner
- Department of Otorhinolaryngology-Head and Neck Surgery, Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany.
| | - C Honeder
- Department of Otorhinolaryngology-Head and Neck Surgery, Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany
| | - W Knolle
- Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany
| | - W Binder
- Institute of Chemistry, Martin-Luther University of Halle-Wittenberg, Halle (Saale), Germany
| | - J Scheffler
- Department of Otorhinolaryngology-Head and Neck Surgery, Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany
| | - S K Plontke
- Department of Otorhinolaryngology-Head and Neck Surgery, Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany; Halle Research Centre for Drug Therapy (HRCDT), Halle (Saale), Germany
| | - A Liebau
- Department of Otorhinolaryngology-Head and Neck Surgery, Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany
| | - K Mäder
- Institute of Pharmacy, Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany; Halle Research Centre for Drug Therapy (HRCDT), Halle (Saale), Germany
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Plontke SK, Liebau A, Lehner E, Bethmann D, Mäder K, Rahne T. Safety and audiological outcome in a case series of tertiary therapy of sudden hearing loss with a biodegradable drug delivery implant for controlled release of dexamethasone to the inner ear. Front Neurosci 2022; 16:892777. [PMID: 36203796 PMCID: PMC9530574 DOI: 10.3389/fnins.2022.892777] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 08/16/2022] [Indexed: 11/21/2022] Open
Abstract
Background Intratympanic injections of glucocorticoids have become increasingly common in the treatment of idiopathic sudden sensorineural hearing loss (ISSHL). However, due to their fast elimination, sustained applications have been suggested for local drug delivery to the inner ear. Materials and methods The study is based on a retrospective chart review of patients treated for ISSHL at a single tertiary (university) referral center. We included patients who were treated with a solid, biodegradable, poly(D,L-lactic-co-glycolic acid) (PLGA)-based drug delivery system providing sustained delivery of dexamethasone extracochlear into the round window niche (n = 15) or intracochlear into scala tympani (n = 2) for tertiary therapy of ISSHL in patients without serviceable hearing after primary systemic and secondary intratympanic glucocorticoid therapy. We evaluated the feasibility and safety through clinical evaluation, histological examination, and functional tests [pure-tone threshold (PTA), word recognition scores (WRS)]. Results With adequate surgical preparation of the round window niche, implantation was feasible in all patients. Histologic examination of the material in the round window niche showed signs of resorption without relevant inflammation or foreign body reaction to the implant. In patients where the basal part of scala tympani was assessable during later cochlear implantation, no pathological findings were found. In the patients with extracochlear application, average preoperative PTA was 84.7 dB HL (SD: 20.0) and 76.7 dB HL (SD: 16.7) at follow-up (p = 0.08). The preoperative average maximum WRS was 14.6% (SD: 17.9) and 39.3% (SD: 30.7) at follow-up (p = 0.11). Six patients (40%), however, reached serviceable hearing. The two patients with intracochlear application did not improve. Conclusion The extracochlear application of the controlled release system in the round window niche and – based on limited observations - intracochlear implantation into scala tympani appears feasible and safe. Due to the uncontrolled study design, conclusions about the efficacy of the treatment are limited. These observations, however, may encourage the initiation of prospective controlled studies using biodegradable controlled release implants as drug delivery systems for the treatment of inner ear diseases.
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Affiliation(s)
- Stefan K. Plontke
- Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
- *Correspondence: Stefan K. Plontke,
| | - Arne Liebau
- Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Eric Lehner
- Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Daniel Bethmann
- Institute of Pathology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Karsten Mäder
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Torsten Rahne
- Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
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7
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Khurana L, Keppeler D, Jablonski L, Moser T. Model-based prediction of optogenetic sound encoding in the human cochlea by future optical cochlear implants. Comput Struct Biotechnol J 2022; 20:3621-3629. [PMID: 35860414 PMCID: PMC9283772 DOI: 10.1016/j.csbj.2022.06.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 01/17/2023] Open
Abstract
When hearing fails, electrical cochlear implants (eCIs) partially restore hearing by direct stimulation of spiral ganglion neurons (SGNs). As light can be better confined in space than electrical current, optical CIs (oCIs) provide more spectral information promising a fundamental improvement of hearing restoration by cochlear implants. Here, we turned to computer modelling for predicting the outcome of optogenetic hearing restoration by future oCIs in humans. We combined three-dimensional reconstruction of the human cochlea with ray-tracing simulation of emission from LED or laser-coupled waveguide emitters of the oCI. Irradiance was read out at the somata of SGNs. The irradiance values reached with waveguides were about 14 times higher than with LEDs, at the same radiant flux of the emitter. Moreover, waveguides outperformed LEDs regarding spectral selectivity. oCIs with either emitter type showed greater spectral selectivity when compared to eCI. In addition, modeling the effects of the source-to-SGN distance, orientation of the sources and impact of scar tissue further informs the development of optogenetic hearing restoration.
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Affiliation(s)
- Lakshay Khurana
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- Auditory Neuroscience & Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences (GGNB), University of Göttingen, Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience & Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Lukasz Jablonski
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- Auditory Neuroscience & Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
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8
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Controlled release of low-molecular weight, polymer-free corticosteroid coatings suppresses fibrotic encapsulation of implanted medical devices. Biomaterials 2022; 286:121586. [DOI: 10.1016/j.biomaterials.2022.121586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 05/12/2022] [Accepted: 05/15/2022] [Indexed: 11/23/2022]
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9
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Matin-Mann F, Gao Z, Schwieger J, Ulbricht M, Domsta V, Senekowitsch S, Weitschies W, Seidlitz A, Doll K, Stiesch M, Lenarz T, Scheper V. Individualized, Additively Manufactured Drug-Releasing External Ear Canal Implant for Prevention of Postoperative Restenosis: Development, In Vitro Testing, and Proof of Concept in an Individual Curative Trial. Pharmaceutics 2022; 14:pharmaceutics14061242. [PMID: 35745813 PMCID: PMC9228097 DOI: 10.3390/pharmaceutics14061242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/16/2022] Open
Abstract
Postoperative restenosis in patients with external ear canal (EEC) atresia or stenosis is a common complication following canaloplasty. Our aim in this study was to explore the feasibility of using a three dimensionally (3D)-printed, patient-individualized, drug ((dexamethasone (DEX)), and ciprofloxacin (cipro))-releasing external ear canal implant (EECI) as a postoperative stent after canaloplasty. We designed and pre-clinically tested this novel implant for drug release (by high-performance liquid chromatography), biocompatibility (by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay), bio-efficacy (by the TNF-α (tumor necrosis factor-alpha)-reduction test (DEX) and inhibition zone test (for cipro)), and microbial contamination (formation of turbidity or sediments in culture medium). The EECI was implanted for the first time to one patient with a history of congenital EEC atresia and state after three canaloplasties due to EEC restenosis. The preclinical tests revealed no cytotoxic effect of the used materials; an antibacterial effect was verified against the bacteria Staphylococcus aureus and Pseudomonas aeruginosa, and the tested UV-irradiated EECI showed no microbiological contamination. Based on the test results, the combination of silicone with 1% DEX and 0.3% cipro was chosen to treat the patient. The EECI was implantable into the EEC; the postoperative follow-up visits revealed no otogenic symptoms or infections and the EECI was explanted three months postoperatively. Even at 12 months postoperatively, the EEC showed good epithelialization and patency. Here, we report the first ever clinical application of an individualized, drug-releasing, mechanically flexible implant and suggest that our novel EECI represents a safe and effective method for postoperatively stenting the reconstructed EEC.
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Affiliation(s)
- Farnaz Matin-Mann
- Department of Otorhinolaryngology, Head and Neck Surgery, Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany; (Z.G.); (J.S.); (T.L.); (V.S.)
- Correspondence: ; Tel.: +49-511-532-6565; Fax: +49-511-532-8001
| | - Ziwen Gao
- Department of Otorhinolaryngology, Head and Neck Surgery, Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany; (Z.G.); (J.S.); (T.L.); (V.S.)
- Cluster of Excellence”Hearing4all” EXC 1077/1, 30625 Hannover, Germany
| | - Jana Schwieger
- Department of Otorhinolaryngology, Head and Neck Surgery, Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany; (Z.G.); (J.S.); (T.L.); (V.S.)
- Cluster of Excellence”Hearing4all” EXC 1077/1, 30625 Hannover, Germany
| | - Martin Ulbricht
- Center of Drug Absorption and Transport, Department of Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (M.U.); (V.D.); (S.S.); (W.W.); (A.S.)
| | - Vanessa Domsta
- Center of Drug Absorption and Transport, Department of Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (M.U.); (V.D.); (S.S.); (W.W.); (A.S.)
| | - Stefan Senekowitsch
- Center of Drug Absorption and Transport, Department of Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (M.U.); (V.D.); (S.S.); (W.W.); (A.S.)
| | - Werner Weitschies
- Center of Drug Absorption and Transport, Department of Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (M.U.); (V.D.); (S.S.); (W.W.); (A.S.)
| | - Anne Seidlitz
- Center of Drug Absorption and Transport, Department of Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (M.U.); (V.D.); (S.S.); (W.W.); (A.S.)
- Institute of Pharmaceutics and Biopharmaceutics, University of Duesseldorf, 40225 Dusseldorf, Germany
| | - Katharina Doll
- Clinic for Dental Prosthetics and Biomedical Materials Science, Hanover Medical School, 30625 Hannover, Germany; (K.D.); (M.S.)
| | - Meike Stiesch
- Clinic for Dental Prosthetics and Biomedical Materials Science, Hanover Medical School, 30625 Hannover, Germany; (K.D.); (M.S.)
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany; (Z.G.); (J.S.); (T.L.); (V.S.)
- Cluster of Excellence”Hearing4all” EXC 1077/1, 30625 Hannover, Germany
| | - Verena Scheper
- Department of Otorhinolaryngology, Head and Neck Surgery, Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany; (Z.G.); (J.S.); (T.L.); (V.S.)
- Cluster of Excellence”Hearing4all” EXC 1077/1, 30625 Hannover, Germany
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10
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Blebea CM, Ujvary LP, Necula V, Dindelegan MG, Perde-Schrepler M, Stamate MC, Cosgarea M, Maniu AA. Current Concepts and Future Trends in Increasing the Benefits of Cochlear Implantation: A Narrative Review. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:747. [PMID: 35744010 PMCID: PMC9229893 DOI: 10.3390/medicina58060747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/25/2022] [Accepted: 05/29/2022] [Indexed: 01/29/2023]
Abstract
Hearing loss is the most common neurosensory disorder, and with the constant increase in etiological factors, combined with early detection protocols, numbers will continue to rise. Cochlear implantation has become the gold standard for patients with severe hearing loss, and interest has shifted from implantation principles to the preservation of residual hearing following the procedure itself. As the audiological criteria for cochlear implant eligibility have expanded to include patients with good residual hearing, more attention is focused on complementary development of otoprotective agents, electrode design, and surgical approaches. The focus of this review is current aspects of preserving residual hearing through a summary of recent trends regarding surgical and pharmacological fundamentals. Subsequently, the assessment of new pharmacological options, novel bioactive molecules (neurotrophins, growth factors, etc.), nanoparticles, stem cells, and gene therapy are discussed.
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Affiliation(s)
- Cristina Maria Blebea
- Department of Otorhinolaryngology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400347 Cluj Napoca, Romania; (C.M.B.); (V.N.); (M.G.D.); (M.C.S.); (M.C.); (A.A.M.)
| | - Laszlo Peter Ujvary
- Department of Otorhinolaryngology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400347 Cluj Napoca, Romania; (C.M.B.); (V.N.); (M.G.D.); (M.C.S.); (M.C.); (A.A.M.)
| | - Violeta Necula
- Department of Otorhinolaryngology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400347 Cluj Napoca, Romania; (C.M.B.); (V.N.); (M.G.D.); (M.C.S.); (M.C.); (A.A.M.)
- County Clinical Emergency Hospital Cluj, 400347 Cluj Napoca, Romania
| | - Maximilian George Dindelegan
- Department of Otorhinolaryngology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400347 Cluj Napoca, Romania; (C.M.B.); (V.N.); (M.G.D.); (M.C.S.); (M.C.); (A.A.M.)
| | | | - Mirela Cristina Stamate
- Department of Otorhinolaryngology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400347 Cluj Napoca, Romania; (C.M.B.); (V.N.); (M.G.D.); (M.C.S.); (M.C.); (A.A.M.)
| | - Marcel Cosgarea
- Department of Otorhinolaryngology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400347 Cluj Napoca, Romania; (C.M.B.); (V.N.); (M.G.D.); (M.C.S.); (M.C.); (A.A.M.)
| | - Alma Aurelia Maniu
- Department of Otorhinolaryngology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400347 Cluj Napoca, Romania; (C.M.B.); (V.N.); (M.G.D.); (M.C.S.); (M.C.); (A.A.M.)
- County Clinical Emergency Hospital Cluj, 400347 Cluj Napoca, Romania
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11
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Madamsetty VS, Mohammadinejad R, Uzieliene I, Nabavi N, Dehshahri A, García-Couce J, Tavakol S, Moghassemi S, Dadashzadeh A, Makvandi P, Pardakhty A, Aghaei Afshar A, Seyfoddin A. Dexamethasone: Insights into Pharmacological Aspects, Therapeutic Mechanisms, and Delivery Systems. ACS Biomater Sci Eng 2022; 8:1763-1790. [PMID: 35439408 PMCID: PMC9045676 DOI: 10.1021/acsbiomaterials.2c00026] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dexamethasone (DEX) has been widely used to treat a variety of diseases, including autoimmune diseases, allergies, ocular disorders, cancer, and, more recently, COVID-19. However, DEX usage is often restricted in the clinic due to its poor water solubility. When administered through a systemic route, it can elicit severe side effects, such as hypertension, peptic ulcers, hyperglycemia, and hydro-electrolytic disorders. There is currently much interest in developing efficient DEX-loaded nanoformulations that ameliorate adverse disease effects inhibiting advancements in scientific research. Various nanoparticles have been developed to selectively deliver drugs without destroying healthy cells or organs in recent years. In the present review, we have summarized some of the most attractive applications of DEX-loaded delivery systems, including liposomes, polymers, hydrogels, nanofibers, silica, calcium phosphate, and hydroxyapatite. This review provides our readers with a broad spectrum of nanomedicine approaches to deliver DEX safely.
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Affiliation(s)
- Vijay Sagar Madamsetty
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Jacksonville, Florida 32224, United States
| | - Reza Mohammadinejad
- Research Center of Tropical and Infectious Diseases, Kerman University of Medical Sciences, Kerman 7618866749, Iran
| | - Ilona Uzieliene
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, Santariskiu 5, LT-08406 Vilnius, Lithuania
| | - Noushin Nabavi
- Department of Urologic Sciences, Vancouver Prostate Centre, Vancouver, British Columbia, Canada V6H 3Z6
| | - Ali Dehshahri
- Center for Nanotechnology in Drug Delivery, Shiraz University of Medical Sciences, Shiraz 7146864685, Iran
| | - Jomarien García-Couce
- Department of Radiology, Division of Translational Nanobiomaterials and Imaging, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands
- Department of Polymeric Biomaterials, Biomaterials Center (BIOMAT), University of Havana, Havana 10600, Cuba
| | - Shima Tavakol
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran 1417755469, Iran
| | - Saeid Moghassemi
- Pôle de Recherche en Gynécologie, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels 1200, Belgium
| | - Arezoo Dadashzadeh
- Pôle de Recherche en Gynécologie, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels 1200, Belgium
| | - Pooyan Makvandi
- Istituto Italiano di Tecnologia, Centre for Micro-BioRobotics, Viale Rinaldo Piaggio 34, 56025 Pontedera, Pisa, Italy
- Department of Medical Nanotechnology, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 14496-14535, Iran
| | - Abbas Pardakhty
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman 7618866748, Iran
| | - Abbas Aghaei Afshar
- Research Center of Tropical and Infectious Diseases, Kerman University of Medical Sciences, Kerman 7618866749, Iran
| | - Ali Seyfoddin
- Drug Delivery Research Group, Auckland University of Technology (AUT), School of Science, Auckland 1010, New Zealand
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Jung SY, Kim S, Kang Z, Kwon S, Lee J, Park JW, Kim KS, Kim DK. Efficiency of a dexamethasone nanosuspension as an intratympanic injection for acute hearing loss. Drug Deliv 2021; 29:149-160. [PMID: 34967280 PMCID: PMC8725939 DOI: 10.1080/10717544.2021.2021320] [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] [Indexed: 11/25/2022] Open
Abstract
Dexamethasone sodium phosphate (Dex-SP) is the most commonly used drug administered via intratympanic injection for the treatment of acute hearing loss, but its penetration efficiency into the inner ear is very low. To address this problem, we evaluated the possibility of administering dexamethasone nanosuspensions via intratympanic injection because hydrophobic drugs might be more effective in penetrating the inner ear. Three types of dexamethasone nanosuspensions were prepared; the dexamethasone nanoparticles in the three nanosuspensions were between approximately 250 and 350 nm in size. To compare the efficiency of Dex-SP and dexamethasone nanosuspension in delivering dexamethasone to the inner ear, the concentrations of dexamethasone in perilymph and cochlear tissues were compared by liquid chromatography–mass spectrometry. The dexamethasone nanosuspensions resulted in significantly higher drug concentrations in perilymph and cochlear tissues than Dex-SP at 6 h; interestingly, animals treated with nanosuspensions showed a 26-fold higher dexamethasone concentrations in their cochlear tissues than animals treated with Dex-SP. In addition, dexamethasone nanosuspension caused better glucocorticoid receptor phosphorylation than Dex-SP both in vitro and in vivo, and in the ototoxic animal model, the nanosuspension showed a significantly better hearing-protective effect against ototoxic drugs than Dex-SP. In the in vivo safety evaluation, the nanosuspension showed no toxicity at concentrations up to 20 mg/mL. In conclusion, a nanosuspension of dexamethasone was able to deliver dexamethasone to the cochlea very safely and efficiently and showed potential as a formula for intratympanic injection.
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Affiliation(s)
- So-Young Jung
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea, Daejeon, Republic of Korea
| | - Subin Kim
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea, Daejeon, Republic of Korea
| | - Zion Kang
- Bio-Synectics, Inc., Seoul, Republic of Korea
| | - Soonmin Kwon
- Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Daejeon, Republic of Korea
| | - Juhye Lee
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea, Daejeon, Republic of Korea
| | | | - Kab Sig Kim
- Bio-Synectics, Inc., Seoul, Republic of Korea
| | - Dong-Kee Kim
- Department of Otolaryngology, College of Medicine, The Catholic University of Korea, Daejeon, Republic of Korea
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Abstract
PURPOSE OF REVIEW Treatment of auditory dysfunction is dependent on inner ear drug delivery, with microtechnologies playing an increasingly important role in cochlear access and pharmacokinetic profile control. This review examines recent developments in the field for clinical and animal research environments. RECENT FINDINGS Micropump technologies are being developed for dynamic control of flow rates with refillable reservoirs enabling timed delivery of multiple agents for protection or regeneration therapies. These micropumps can be combined with cochlear implants with integral catheters or used independently with cochleostomy or round window membrane (RWM) delivery modalities for therapy development in animal models. Sustained release of steroids with coated cochlear implants remains an active research area with first-time-in-human demonstration of reduced electrode impedances. Advanced coatings containing neurotrophin producing cells have enhanced spiral ganglion neuron survival in animal models, and have proven safe in a human study. Microneedles have emerged for controlled microperforation of the RWM for significant enhancement in permeability, combinable with emerging matrix formulations that optimize biological interaction and drug release kinetics. SUMMARY Microsystem technologies are providing enhanced and more controlled access to the inner ear for advanced drug delivery approaches, alone and in conjunction with cochlear implants.
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Pawley DC, Goncalves S, Bas E, Dikici E, Deo SK, Daunert S, Telischi F. Dexamethasone (DXM)‐Coated Poly(lactic‐
co
‐glycolic acid) (PLGA) Microneedles as an Improved Drug Delivery System for Intracochlear Biodegradable Devices. ADVANCED THERAPEUTICS 2021. [DOI: 10.1002/adtp.202100155] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Devon C. Pawley
- Department of Biochemistry and Molecular Biology University of Miami Miller School of Medicine Miami FL 33136 USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute of the University of Miami Miami FL 33136 USA
| | - Stefania Goncalves
- University of Miami Ear Institute Department of Otolaryngology University of Miami Miller School of Medicine Miami FL 33136 USA
| | - Esperanza Bas
- University of Miami Ear Institute Department of Otolaryngology University of Miami Miller School of Medicine Miami FL 33136 USA
| | - Emre Dikici
- Department of Biochemistry and Molecular Biology University of Miami Miller School of Medicine Miami FL 33136 USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute of the University of Miami Miami FL 33136 USA
| | - Sapna K. Deo
- Department of Biochemistry and Molecular Biology University of Miami Miller School of Medicine Miami FL 33136 USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute of the University of Miami Miami FL 33136 USA
| | - Sylvia Daunert
- Department of Biochemistry and Molecular Biology University of Miami Miller School of Medicine Miami FL 33136 USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute of the University of Miami Miami FL 33136 USA
- University of Miami Clinical and Translational Science Institute University of Miami Miller School of Medicine Miami FL 33136 USA
| | - Fred Telischi
- University of Miami Ear Institute Department of Otolaryngology University of Miami Miller School of Medicine Miami FL 33136 USA
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Kather M, Koitzsch S, Breit B, Plontke S, Kammerer B, Liebau A. Metabolic reprogramming of inner ear cell line HEI-OC1 after dexamethasone application. Metabolomics 2021; 17:52. [PMID: 34028607 PMCID: PMC8144088 DOI: 10.1007/s11306-021-01799-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/29/2021] [Indexed: 12/26/2022]
Abstract
INTRODUCTION One approach to dampen the inflammatory reactions resulting from implantation surgery of cochlear implant hearing aids is to embed dexamethasone into the matrix of the electrode carrier. Possible side effects for sensory cells in the inner ear on the metabolomics have not yet been evaluated. OBJECTIVE We examined changes in the metabolome of the HEI-OC1 cell line after dexamethasone incubation as a cell model of sensory cells of the inner ear. RESULTS AND CONCLUSION Untargeted GC-MS-profiling of metabolic alterations after dexamethasone treatment showed that dexamethasone had antithetical effects on the metabolic signature of the cells depending on growth conditions. The differentiated state of HEI-OC1 cells is better suited for elucidating metabolic changes induced by external factors. Dexamethasone treatment of differentiated cells led to an increase in intracellular amino acids and enhanced glucose uptake and β-oxidation in the cells. Increased availability of precursors for glycolysis and ATP production by β-oxidation stabilizes the energy supply in the cells, which could be assumed to be beneficial in coping with cellular stress. We found no negative effects of dexamethasone on the metabolic level, and changes may even prepare sensory cells to better overcome cellular stress following implantation surgery.
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Affiliation(s)
- Michel Kather
- Centre for Integrative Biological Signalling Studies CISA, University of Freiburg, Habsburger Straße 49, 79104, Freiburg, Germany
- Hermann Staudinger Graduate School, University of Freiburg, Hebelstr. 27, 79104, Freiburg, Germany
- Institute of Organic Chemistry, University of Freiburg, Albertstraße 21, 79104, Freiburg, Germany
| | - Sabine Koitzsch
- Department of Otorhinolaryngology-Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Ernst-Grube-Straße 40, 06120, Halle (Saale), Germany
| | - Bernhard Breit
- Institute of Organic Chemistry, University of Freiburg, Albertstraße 21, 79104, Freiburg, Germany
| | - Stefan Plontke
- Department of Otorhinolaryngology-Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Ernst-Grube-Straße 40, 06120, Halle (Saale), Germany
| | - Bernd Kammerer
- Centre for Integrative Biological Signalling Studies CISA, University of Freiburg, Habsburger Straße 49, 79104, Freiburg, Germany.
- Institute of Organic Chemistry, University of Freiburg, Albertstraße 21, 79104, Freiburg, Germany.
- Centre for Biological Signalling Studies BIOSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany.
- Center for Biosystems Analysis, ZBSA, University of Freiburg, Habsburgerstr. 49, 79104, Freiburg, Germany.
| | - Arne Liebau
- Department of Otorhinolaryngology-Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Ernst-Grube-Straße 40, 06120, Halle (Saale), Germany.
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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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