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Wei C, Gao Z, Knabel M, Ulbricht M, Senekowitsch S, Erfurt P, Maggi N, Zwick B, Eickner T, Matin-Mann F, Seidlitz A, Lenarz T, Scheper V. Development of a drug delivering round window niche implant for cochlear pharmacotherapy. Drug Deliv 2024; 31:2392755. [PMID: 39166341 PMCID: PMC11340218 DOI: 10.1080/10717544.2024.2392755] [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: 01/18/2024] [Revised: 08/08/2024] [Accepted: 08/11/2024] [Indexed: 08/22/2024] Open
Abstract
BACKGROUND There exists an unfulfilled requirement for effective cochlear pharmacotherapy. Controlled local drug delivery could lead to effective bioavailability. The round window niche (RWN), a cavity in the middle ear, is connected to the cochlea via a membrane through which drug can diffuse. We are developing individualized drug-eluting RWN implants (RNIs). To test their effectiveness in guinea pigs, a commonly used model in cochlear pharmacology studies, it is first necessary to develop guinea pig RNIs (GP-RNI). METHODS Since guinea pigs do not have a RWN such as it is present in humans and to reduce the variables in in vivo studies, a one-size-fits-all GP-RNI model was designed using 12 data sets of Dunkin-Hartley guinea pigs. The model was 3D-printed using silicone. The accuracy and precision of printing, distribution of the sample ingredient dexamethasone (DEX), biocompatibility, bio-efficacy, implantability and drug release were tested in vitro. The GP-RNI efficacy was validated in cochlear implant-traumatized guinea pigs in vivo. RESULTS The 3D-printed GP-RNI was precise, accurate and fitted in all tested guinea pig RWNs. DEX was homogeneously included in the silicone. The GP-RNI containing 1% DEX was biocompatible, bio-effective and showed a two-phase and sustained DEX release in vitro, while it reduced fibrous tissue growth around the cochlear implant in vivo. CONCLUSIONS We developed a GP-RNI that can be used for precise inner ear drug delivery in guinea pigs, providing a reliable platform for testing the RNI's safety and efficacy, with potential implications for future clinical translation.
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Affiliation(s)
- Chunjiang Wei
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4all”, German Research Foundation (DFG, “Deutsche Forschungsgemeinschaft”), Hannover Medical School, Lower Saxony, Germany
| | - Ziwen Gao
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4all”, German Research Foundation (DFG, “Deutsche Forschungsgemeinschaft”), Hannover Medical School, Lower Saxony, Germany
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
| | - Martina Knabel
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Martin Ulbricht
- Center of Drug Absorption and Transport, Department of Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Stefan Senekowitsch
- Center of Drug Absorption and Transport, Department of Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Peter Erfurt
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | | | - Bastian Zwick
- Carl Zeiss Industrielle Messtechnik GmbH, ZEISS Group, Essingen, Germany
| | - Thomas Eickner
- Institute for Biomedical Engineering, University Medical Center Rostock, University of Rostock, Rostock, Germany
| | - Farnaz Matin-Mann
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Anne Seidlitz
- Center of Drug Absorption and Transport, Department of Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
- Institute of Pharmaceutics and Biopharmaceutics, University of Duesseldorf, Duesseldorf, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4all”, German Research Foundation (DFG, “Deutsche Forschungsgemeinschaft”), Hannover Medical School, Lower Saxony, Germany
| | - Verena Scheper
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4all”, German Research Foundation (DFG, “Deutsche Forschungsgemeinschaft”), Hannover Medical School, Lower Saxony, Germany
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Wang L, Zhang R, Jiang L, Gao S, Wu J, Jiao Y. Biomaterials as a new option for treating sensorineural hearing loss. Biomater Sci 2024; 12:4006-4023. [PMID: 38979939 DOI: 10.1039/d4bm00518j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Sensorineural hearing loss (SNHL) usually involves damage to complex auditory pathways such as inner ear cells and auditory nerves. The highly intricate and nuanced characteristics of these cells render their repair and regeneration extremely challenging, making it difficult to restore hearing to normal levels once it has been compromised. The effectiveness of traditional drugs is so minimal that they provide little help with the treatment. Fortunately, extensive experiments have demonstrated that combining biomaterials with conventional techniques significantly enhances drug effectiveness. This article reviews the research progress of biomaterials in protecting hair cells and the auditory nerve, repairing genes related to hearing, and developing artificial cochlear materials. By organizing the knowledge presented in this article, perhaps new insights can be provided for the clinical management of SNHL.
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Affiliation(s)
- Liwen Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Guangzhou Twelfth People's Hospital (The Affiliated Twelfth People's Hospital of Guangzhou Medical University), Guangzhou 510620, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, Guangzhou Medical University, Guangzhou 510620, China.
| | - Ruhe Zhang
- Department of Hematology, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen 518107, China
| | - Linlan Jiang
- Department of Otorhinolaryngology Head and Neck Surgery, Guangzhou Twelfth People's Hospital (The Affiliated Twelfth People's Hospital of Guangzhou Medical University), Guangzhou 510620, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, Guangzhou Medical University, Guangzhou 510620, China.
| | - Shuyi Gao
- Department of Otorhinolaryngology Head and Neck Surgery, Guangzhou Twelfth People's Hospital (The Affiliated Twelfth People's Hospital of Guangzhou Medical University), Guangzhou 510620, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, Guangzhou Medical University, Guangzhou 510620, China.
| | - Jun Wu
- Institute of Otorhinolaryngology, Head and Neck Surgery, Guangzhou Medical University, Guangzhou 510620, China.
- Bioscience and Biomedical Engineering Thrust, The Hong Kong University of Science and Technology (Guangzhou), Nansha, Guangzhou 511400, China.
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yuenong Jiao
- Department of Otorhinolaryngology Head and Neck Surgery, Guangzhou Twelfth People's Hospital (The Affiliated Twelfth People's Hospital of Guangzhou Medical University), Guangzhou 510620, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, Guangzhou Medical University, Guangzhou 510620, China.
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Hosoya M, Kurihara S, Koyama H, Komune N. Recent advances in Otology: Current landscape and future direction. Auris Nasus Larynx 2024; 51:605-616. [PMID: 38552424 DOI: 10.1016/j.anl.2024.02.009] [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: 08/22/2023] [Revised: 11/24/2023] [Accepted: 02/21/2024] [Indexed: 05/12/2024]
Abstract
Hearing is an essential sensation, and its deterioration leads to a significant decrease in the quality of life. Thus, great efforts have been made by otologists to preserve and recover hearing. Our knowledge regarding the field of otology has progressed with advances in technology, and otologists have sought to develop novel approaches in the field of otologic surgery to achieve higher hearing recovery or preservation rates. This requires knowledge regarding the anatomy of the temporal bone and the physiology of hearing. Basic research in the field of otology has progressed with advances in molecular biology and genetics. This review summarizes the current views and recent advances in the field of otology and otologic surgery, especially from the viewpoint of young Japanese clinician-scientists, and presents the perspectives and future directions for several topics in the field of otology. This review will aid next-generation researchers in understanding the recent advances and future challenges in the field of otology.
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Affiliation(s)
- Makoto Hosoya
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, Shinanomachi 35, Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Sho Kurihara
- Department of Otorhinolaryngology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan
| | - Hajime Koyama
- Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-8654, Japan
| | - Noritaka Komune
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, 3-1-1Maidashi Higashi-ku, Fukuoka 812-8582, Japan
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Yancey KL, Patro A, Smetak M, Perkins EL, Isaacson B, Bennett ML, O'Malley M, Haynes DS, Hunter JB. Evaluating calcium channel blockers and bisphosphonates as otoprotective agents in cochlear implantation hearing preservation candidates. Cochlear Implants Int 2024:1-9. [PMID: 38738388 DOI: 10.1080/14670100.2024.2338003] [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: 05/14/2024]
Abstract
OBJECTIVES Evaluate potential effects of calcium channel blockers (CCB) and bisphosphonates (BP) on residual hearing following cochlear implantation. METHODS Medications of 303 adult hearing preservation (HP) candidates (low frequency pure tone average [LFPTA] of 125, 250, and 500 Hz ≤80 dB HL) were reviewed. Postimplantation LFPTA of patients taking CCBs and BPs were compared to controls matched by age and preimplantation LFPTA. RESULTS Twenty-six HP candidates were taking a CCB (N = 14) or bisphosphonate (N = 12) at implantation. Median follow-up was 1.37 years (range 0.22-4.64y). Among subjects with initial HP, 29% (N = 2 of 7) CCB users compared to 50% (N = 2 of 4) controls subsequently lost residual hearing 3-6 months later (OR = 0.40, 95% CI = 0.04-4.32, p = 0.58). None of the four BP patients with initial HP experienced delayed loss compared to 50% (N = 2 of 4) controls with initial HP (OR = 0.00, 95% CI = 0.00-1.95, P = 0.43). Two CCB and one BP patients improved to a LFPTA <80 dB HL following initial unaided thresholds that suggested loss of residual hearing. DISCUSSION There were no significant differences in the odds of delayed loss of residual hearing with CCBs or BPs. CONCLUSION Further investigation into potential otoprotective adjuvants for maintaining residual hearing following initial successful hearing preservation is warranted, with larger cohorts and additional CCB/BP agents.
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Affiliation(s)
- Kristen L Yancey
- Department of Otolaryngology-Head and Neck Surgery, Weill Cornell Medical Center/New York Presbyterian Hospital, New York, NY, USA
| | - Ankita Patro
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Miriam Smetak
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Elizabeth L Perkins
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Brandon Isaacson
- Department of Otolaryngology-Head and Neck Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Marc L Bennett
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Matthew O'Malley
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - David S Haynes
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jacob B Hunter
- Department of Otolaryngology-Head and Neck Surgery, Thomas Jefferson University Hospital, Philadelphia, PA, USA
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Razmovski T, Brody KM, Stathopoulos D, Zhang D, Cho E, Hampson AJ, Collins A, Bester C, O'Leary S. Intra-cochlear Flushing Reduces Tissue Response to Cochlear Implantation. Laryngoscope 2024; 134:1410-1416. [PMID: 37694764 DOI: 10.1002/lary.31022] [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: 03/15/2023] [Revised: 07/02/2023] [Accepted: 08/14/2023] [Indexed: 09/12/2023]
Abstract
INTRODUCTION Intraoperative trauma leading to bleeding during cochlear implantation negatively impacts residual hearing of cochlear implant recipients. There are no clinical protocols for the removal of blood during implantation, to reduce the consequential effects such as inflammation and fibrosis which adversely affect cochlear health and residual hearing. This preclinical study investigated the implementation of an intra-cochlear flushing protocol for the removal of blood. METHODS Three groups of guinea pigs were studied for 28 days after cochlear implantation; cochlear implant-only (control group); cochlear implant with blood injected into the cochlea (blood group); and cochlear implant, blood injection, and flushing of the blood from the cochlea intraoperatively (flush group). Auditory brainstem responses (ABRs) in addition to tissue response volumes were analyzed and compared between groups. RESULTS After implantation, the blood group exhibited the highest ABR thresholds when compared to the control and flush group, particularly in the high frequencies. On the final day, the control and blood group had similar ABR thresholds across all frequencies tested, whereas the flush group had the lowest thresholds, significantly lower at 24 kHz than the blood and control group. Analysis of the tissue response showed the flush group had significantly lower tissue responses in the basal half of the array when compared with the blood and control group. CONCLUSIONS Flushing intra-cochlear blood during surgery resulted in better auditory function and reduced subsequent fibrosis in the basal region of the cochlea. This finding prompts the implementation of a flushing protocol in clinical cochlear implantation. LEVEL OF EVIDENCE N/A Laryngoscope, 134:1410-1416, 2024.
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Affiliation(s)
- Tayla Razmovski
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Kate M Brody
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Dimitra Stathopoulos
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Dongcheng Zhang
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Ellie Cho
- Biological Optical Microscopy Platform, University of Melbourne, Parkville, Victoria, Australia
| | - Amy J Hampson
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Aaron Collins
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Christofer Bester
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Stephen O'Leary
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
- The Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
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Xu M, Chen A, Chen D, Wu S, Deng Z, Wen H, Zhong H, Lu K, Tang J, Ma D, Zhang H. Preparation, characterization, and in vitro/vivo evaluation of a multifunctional electrode coating for cochlear implants. BIOMATERIALS ADVANCES 2024; 157:213736. [PMID: 38128170 DOI: 10.1016/j.bioadv.2023.213736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 11/11/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Cochlear implantation (CI) is the primary intervention for patients with sensorineural hearing loss to restore their hearing. However, approximately 90 % of CI recipients experience unexpected fibrosis around the inserted electrode arrays due to acute and chronic inflammation. This fibrosis leads to progressive residual hearing loss. Addressing this complication is crucial for enhancing CI outcomes, yet an effective treatment has not yet been found. In this study, we developed a multifunctional dexamethasone (DXM)-loaded polytrimethylene carbonate (PTMC) electrode coating to mitigate inflammatory reactions and fibrosis after CI. This thin and flexible coating could preserve the mechanical performance of the electrode and reduce the implantation resistance for CI. The in vitro release studies demonstrated the DXM-PTMC coating's efficient drug loading and sustained release capability over 90 days. DXM-PTMC also showed long-term stability, high biocompatibility, and effective anti-inflammatory effects in vitro and in vivo. Compared with the uncoated group, DXM-PTMC coating significantly inhibited the expression of inflammatory factors, such as NO, TNF-α, IL-1β, and IL-6. DXM-PTMC coating suppressed fibrosis in rat implantation models for 3 weeks by reducing both acute and chronic inflammation. Our findings suggest that DXM-PTMC coating is a novel strategy to improve the outcomes of CI.
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Affiliation(s)
- Muqing Xu
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Ear Research Institute, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Anning Chen
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Ear Research Institute, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Dongxiu Chen
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Ear Research Institute, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Shengquan Wu
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Zhipeng Deng
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Hang Wen
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Huiling Zhong
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Kejin Lu
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Jie Tang
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Ear Research Institute, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou 510515, China.
| | - Dong Ma
- Guangdong Provincial Engineering and Technological Research Center for Drug Carrier Development, Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou 510632, China.
| | - Hongzheng Zhang
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Ear Research Institute, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China.
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Derdzakyan NA, Lava CX, Hakimi AA, Johns JD, Kim HJ, Hoa M. Variability in Perioperative Steroid Therapy Regimen for Cochlear Implantation as It Relates to Hearing Preservation. Otol Neurotol 2024; 45:e28-e35. [PMID: 38085763 DOI: 10.1097/mao.0000000000004058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
HYPOTHESIS We aimed to identify practice trends and association between physician training and administration of perioperative steroids for cochlear implantation (CI) as it relates to hearing preservation. BACKGROUND Perioperative steroid therapy regimens are postulated to protect residual hearing and improve hearing preservation outcomes in CI. METHODS A 27-question online survey was developed by the senior authors using the Qualtrics Survey Tool, then distributed via email from September to November 2022 to otolaryngologists specializing in otology or neurotology and who practice in the United States or Canada. RESULTS The survey was sent to 463 physicians, 162 (35.0%) of whom completed the survey. One hundred forty-four (31.1%) responses underwent analysis. All physicians administering preoperative steroids (n = 31) prefer preoperative oral prednisone. Of 143 physicians administering intraoperative steroids, 54.5% prefer intraoperative intravenous dexamethasone. More than half (77.6%) of 85 physicians administering postoperative steroids prefer postoperative oral prednisone. Postoperative steroid administration (p < 0.006) and taper utilization (p < 0.041) were greater among physicians who complete greater than 40 CIs annually (n = 47 [71.2%]; n = 30 [49.2%]) than physicians who complete up to 40 CIs annually (n = 37 [48.7%]; n = 20 [31.3%]), respectively. Physicians practicing for 5 to 20 years after residency are more prevalent in using postoperative steroid tapers than physicians practicing for fewer than 5 years after and more than 20 years after residency (n = 37 [51.4%] versus n = 14 [25.5%], p < 0.001). CONCLUSION Consensus is needed about the optimal steroid treatment for CI patients. LEVEL OF EVIDENCE 4.
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Affiliation(s)
| | | | - Amir A Hakimi
- Department of Otolaryngology-Head and Neck Surgery, Georgetown University Medical Center, Washington, DC
| | - J Dixon Johns
- Department of Otolaryngology-Head and Neck Surgery, Georgetown University Medical Center, Washington, DC
| | - H Jeffrey Kim
- Department of Otolaryngology-Head and Neck Surgery, Georgetown University Medical Center, Washington, DC
| | - Michael Hoa
- Department of Otolaryngology-Head and Neck Surgery, Georgetown University Medical Center, Washington, DC
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Behrends W, Ahrens D, Bankstahl JP, Esser KH, Paasche G, Lenarz T, Scheper V. Refinement of systemic guinea pig deafening in hearing research: Sensorineural hearing loss induced by co-administration of kanamycin and furosemide via the leg veins. Lab Anim 2023; 57:631-641. [PMID: 37070340 DOI: 10.1177/00236772231167679] [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] [Indexed: 04/19/2023]
Abstract
Auditory disabilities have a large impact on the human population worldwide. Research into understanding and treating hearing disabilities has increased significantly in recent years. One of the most relevant animal species in this context is the guinea pig, which has to be deafened to study several of the hearing pathologies and develop novel therapies. Applying kanamycin subcutaneously and furosemide intravenously is a long-established method in hearing research, leading to permanent hearing loss without surgical intervention at the ear. The intravenous application of furosemide requires invasive surgery in the cervical area of the animals to expose the jugular vein, since a relatively large volume (1 ml per 500 g body weight) must be injected over a period of about 2.5 min. We have established a gentler alternative by applying the furosemide by puncture of the leg veins. For this, custom-made cannula-needle devices were built to allow the vein puncture and subsequent slow injection of the furosemide. This approach was tested in 11 guinea pigs through the foreleg via the cephalic antebrachial vein and through the hind leg via the saphenous vein. Frequency-specific hearing thresholds were measured before and after the procedure to verify normal hearing and successful deafening, respectively. The novel approach of systemic deafening was successfully implemented in 10 out of 11 animals. The Vena saphena was best suited to the application. Since the animals' condition, post leg vein application, was better in comparison to animals deafened by exposure of the Vena jugularis, the postulated refinement that reduced animal stress was deemed successful.
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Affiliation(s)
- Wiebke Behrends
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Auditory Neuroethology and Neurobiology, Institute of Zoology, University of Veterinary Medicine Hannover Foundation, Germany
| | - Daniel Ahrens
- Department of Nuclear Medicine, Hannover Medical School, Germany
| | - Jens P Bankstahl
- Department of Nuclear Medicine, Hannover Medical School, Germany
| | - Karl-Heinz Esser
- Auditory Neuroethology and Neurobiology, Institute of Zoology, University of Veterinary Medicine Hannover Foundation, Germany
| | - Gerrit Paasche
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Hearing4all Cluster of Excellence, Hannover Medical School, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Hearing4all Cluster of Excellence, Hannover Medical School, Germany
| | - Verena Scheper
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Hearing4all Cluster of Excellence, Hannover Medical School, Germany
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Creber NJ, Eastwood HT, Hampson AJ, O'Leary SJ. Cochlear implant surgery facilitates intracochlear distribution of perioperative systemic steroids. Acta Otolaryngol 2023; 143:647-654. [PMID: 37603289 DOI: 10.1080/00016489.2023.2241877] [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: 05/11/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 08/22/2023]
Abstract
BACKGROUND Systemically administered steroids are widely utilised for hearing preservation therapies. More recently, steroids have been administered to achieve hearing protection after cochlear implant surgery. Currently there is a lack of understanding as to which administration route offers most therapeutic efficacy, local or systemic administration. Paramount to this are observations in animal studies that systemic administration following implantation offers hearing protection and reduced cochlear fibrosis, despite observations that perilymphatic levels are up to 10-fold higher after local administration in non-implanted cochleae. AIMS/OBJECTIVES This paper explores the impact that cochlear implantation and associated acute inflammation has on steroid distribution and uptake following systemic administration of dexamethasone. MATERIAL AND METHODS Eight guinea pigs received systemic dexamethasone 60 min prior to cochlear implantation. Implanted and contralateral non-implanted cochlea were harvested for tissue immunohistochemistry and detection of dexamethasone. RESULTS Cochleostomy with scala tympani implantation resulted in a significant increase in cochlear dexamethasone signal. This was most notable at the organ of Corti, stria vascularis, and blood product in the scala tympani. CONCLUSIONS AND SIGNIFICANCE This study demonstrates that the inner ear distribution of systemically administered steroids is enhanced following surgery for cochlear implantation and provides rationale for systemic perioperative steroids in hearing preservation surgery.
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Affiliation(s)
- Nathan J Creber
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
| | - Hayden T Eastwood
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
| | - Amy J Hampson
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
| | - Stephen J O'Leary
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
- Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
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Razmovski T, Collins A, Bester C, O'Leary S. Using Four-Point Impedance to Detect and Locate Blood during Cochlear Implantation . ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083677 DOI: 10.1109/embc40787.2023.10340312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Biosensing technologies are emerging as an important consideration when designing implantable medical devices. For cochlear implants, biosensors may help preserve the natural hearing a patient has prior to implantation by detecting blood in the cochlea during insertion. If blood enters the cochlea, it creates a hostile environment leading to further hearing loss and reduced device function. Here we present four-point impedance, measured directly from a commercial cochlear implant, as a biosensor for real-time detection of blood in the cochlea. The four-point impedance of different concentrations of whole blood in saline were measured using the impedance-measuring capabilities of a cochlear implant with a square-wave stimulation. Impedance derived from a cochlear implant succeeded in differentiating concentrations of blood in saline with results from a sensitivity analysis showing the lowest concentration the system could detect was between 12 % to 21 % of whole blood. In a subsequent in-vitro study, continuous four-point impedance was measured from a cochlear implant while it was inserted into a 3D printed cochlear model, followed by an injection of blood to emulate surgical events. These results demonstrated four-point impedance from a cochlear implant can instantaneously detect the addition of blood within the cochlea and localize it along the electrode array. The adaptation of a biosensing tool using a cochlear implant provides more information that can be relayed to the surgeon intraoperatively to potentially enhance hearing outcomes with the implant.Clinical Relevance - Using the cochlear implant itself to detect intra-cochlear bleeding may open therapeutic avenues to prevent further hearing loss.
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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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12
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Biological Response Dynamics to Cochlear Implantation: Modeling and Modulating the Electrode–Tissue Interface. Ear Hear 2022; 43:1687-1697. [DOI: 10.1097/aud.0000000000001236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
INTRODUCTION More than 5% of the world's population have a disabling hearing loss which can be managed by hearing aids or implanted electrical devices. However, outcomes are highly variable, and the sound perceived by recipients is far from perfect. Sparked by the discovery of progenitor cells in the cochlea and rapid progress in drug delivery to the cochlea, biological and pharmaceutical therapies are currently in development to improve the function of the cochlear implant or eliminate the need for it altogether. AREAS COVERED This review highlights progress in emerging regenerative strategies to restore hearing and adjunct therapies to augment the cochlear implant. Novel approaches include the reprogramming of progenitor cells to restore the sensory hair cell population in the cochlea, gene therapy and gene editing to treat hereditary and acquired hearing loss. A detailed review of optogenetics is also presented as a technique that could enable optical stimulation of the spiral ganglion neurons, replacing or complementing electrical stimulation. EXPERT OPINION Increasing evidence of substantial reversal of hearing loss in animal models, alongside rapid advances in delivery strategies to the cochlea and learnings from clinical trials will amalgamate into a biological or pharmaceutical therapy to replace or complement the cochlear implant.
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Affiliation(s)
- Elise Ajay
- Bionics Institute, East Melbourne, Victoria, Australia.,University of Melbourne, Department of Engineering
| | | | - Rachael Richardson
- Bionics Institute, East Melbourne, Victoria, Australia.,University of Melbourne, Medical Bionics Department, Parkville, Victoria, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), East Melbourne, Victoria, Australia
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Dohr D, Wulf K, Grabow N, Mlynski R, Schraven SP. A PLLA Coating Does Not Affect the Insertion Pressure or Frictional Behavior of a CI Electrode Array at Higher Insertion Speeds. MATERIALS 2022; 15:ma15093049. [PMID: 35591381 PMCID: PMC9104964 DOI: 10.3390/ma15093049] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/14/2022] [Accepted: 04/14/2022] [Indexed: 01/27/2023]
Abstract
To prevent endocochlear insertion trauma, the development of drug delivery coatings in the field of CI electrodes has become an increasing focus of research. However, so far, the effect of a polymer coating of PLLA on the mechanical properties, such as the insertion pressure and friction of an electrode array, has not been investigated. In this study, the insertion pressure of a PLLA-coated, 31.5-mm long standard electrode array was examined during placement in a linear cochlear model. Additionally, the friction coefficients between a PLLA-coated electrode array and a tissue simulating the endocochlear lining were acquired. All data were obtained at different insertion speeds (0.1, 0.5, 1.0, 1.5, and 2.0 mm/s) and compared with those of an uncoated electrode array. It was shown that both the maximum insertion pressure generated in the linear model and the friction coefficient of the PLLA-coated electrode did not depend on the insertion speed. At higher insertion speeds above 1.0 mm/s, the insertion pressure (1.268 ± 0.032 mmHg) and the friction coefficient (0.40 ± 0.15) of the coated electrode array were similar to those of an uncoated array (1.252 ± 0.034 mmHg and 0.36 ± 0.15). The present study reveals that a PLLA coating on cochlear electrode arrays has a negligible effect on the electrode array insertion pressure and the friction when higher insertion speeds are used compared with an uncoated electrode array. Therefore, PLLA is a suitable material to be used as a coating for CI electrode arrays and can be considered for a potential drug delivery system.
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Affiliation(s)
- Dana Dohr
- Department of Otorhinolaryngology, Head and Neck Surgery “Otto Körner”, Rostock University Medical Center, 18057 Rostock, Germany; (R.M.); (S.P.S.)
- Correspondence: author
| | - Katharina Wulf
- Institute for Biomedical Engineering, Rostock University Medical Center, 18119 Rostock, Germany; (K.W.); (N.G.)
| | - Niels Grabow
- Institute for Biomedical Engineering, Rostock University Medical Center, 18119 Rostock, Germany; (K.W.); (N.G.)
| | - Robert Mlynski
- Department of Otorhinolaryngology, Head and Neck Surgery “Otto Körner”, Rostock University Medical Center, 18057 Rostock, Germany; (R.M.); (S.P.S.)
| | - Sebastian P. Schraven
- Department of Otorhinolaryngology, Head and Neck Surgery “Otto Körner”, Rostock University Medical Center, 18057 Rostock, Germany; (R.M.); (S.P.S.)
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15
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Spironolactone Ameliorates Cochlear Implant Induced Endolymphatic Hydrops. Otol Neurotol 2022; 43:685-693. [DOI: 10.1097/mao.0000000000003517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Li M, Mu Y, Cai H, Wu H, Ding Y. Application of New Materials in Auditory Disease Treatment. Front Cell Neurosci 2022; 15:831591. [PMID: 35173583 PMCID: PMC8841849 DOI: 10.3389/fncel.2021.831591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 12/22/2021] [Indexed: 11/16/2022] Open
Abstract
Auditory diseases are disabling public health problems that afflict a significant number of people worldwide, and they remain largely incurable until now. Driven by continuous innovation in the fields of chemistry, physics, and materials science, novel materials that can be applied to hearing diseases are constantly emerging. In contrast to conventional materials, new materials are easily accessible, inexpensive, non-invasive, with better acoustic therapy effects and weaker immune rejection after implantation. When new materials are used to treat auditory diseases, the wound healing, infection prevention, disease recurrence, hair cell regeneration, functional recovery, and other aspects have been significantly improved. Despite these advances, clinical success has been limited, largely due to issues regarding a lack of effectiveness and safety. With ever-developing scientific research, more novel materials will be facilitated into clinical use in the future.
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Huang Y, Yu H, Liang M, Hou S, Chen J, Zhang F, Sun X, Jia H, Yang J. Hearing Protection Outcomes of Analog Electrode Arrays Coated with Different Drug-Eluting Polymer Films Implanted into Guinea Pig Cochleae. DRUG DESIGN DEVELOPMENT AND THERAPY 2021; 15:3443-3450. [PMID: 34413631 PMCID: PMC8370035 DOI: 10.2147/dddt.s318117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/13/2021] [Indexed: 12/29/2022]
Abstract
Objective To investigate the hearing protection outcomes of different drug-eluting analog electrode arrays implanted into guinea pig cochleae. Methods Sixty guinea pigs were randomly divided into a negative control group and five experimental groups implanted separately with blank (drug carrier), dexamethasone (DXM), aracytine (Ara-C), Ara-C+DXM, and nicotinamide adenine dinucleotide (NAD+) eluting analog electrode arrays. Micro CT was used to supervise the surgical procedure. Auditory brainstem response (ABR) thresholds of the guinea pigs were measured and analyzed. Results and Conclusions Compared with the negative control, all other groups showed a significant increase in ABR threshold (p<0.001) after surgery. Among them, there was no obvious difference between the blank (0 vs 90 days: 59.70±10.57 vs 64.60±9.47 dB SPL) and the NAD+ group (0 vs 90 days: 59.90±9.87 vs 64.70±8.65 dB SPL). On the other hand, the ABR thresholds in the DXM (0 days: 58.10±10.73 dB SPL; 90 days: 51.70±9.07 dB SPL) and the Ara-C group (0 days: 59.00±10.05 dB SPL; 90 days: 51.60±8.48 dB SPL) decreased significantly compared with the former two groups (p<0.001). However, the Ara-C+DXM group showed no further benefit (p>0.05). In addition, a significantly higher survival rate of spiral ganglion neurons in cochleae was observed in the Ara-C and/or DXM groups.
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Affiliation(s)
- Yuyu Huang
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai, 200125, People's Republic of China
| | - Haoran Yu
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People's Republic of China
| | - Min Liang
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai, 200125, People's Republic of China
| | - Shule Hou
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai, 200125, People's Republic of China
| | - Junmin Chen
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai, 200125, People's Republic of China
| | - Fan Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai, 200125, People's Republic of China
| | - Xiayu Sun
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai, 200125, People's Republic of China
| | - Huan Jia
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai, 200125, People's Republic of China.,Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, 200031, People's Republic of China
| | - Jun Yang
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai, 200125, People's Republic of China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, 200031, People's Republic of China
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Luo Y, Chen A, Xu M, Chen D, Tang J, Ma D, Zhang H. Preparation, characterization, and in vitro/ vivo evaluation of dexamethasone/poly(ε-caprolactone)-based electrode coatings for cochlear implants. Drug Deliv 2021; 28:1673-1684. [PMID: 34347538 PMCID: PMC8344245 DOI: 10.1080/10717544.2021.1960927] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
With dexamethasone as the model drug and polycaprolactone (PCL) as the carrier material, a drug delivery coating for cochlear electrodes was prepared, to control cochlear fibrosis caused by cochlear implantation. A dexamethasone/poly (ε-caprolactone)-based electrode coating was prepared using the impregnation coating method. Preparation parameters were optimized, yielding 1 impregnation instance, impregnation time of 10 s, and PCL concentration of 10%. The coating was characterized in vitro using scanning electron microscopy, a universal machine, high-performance liquid chromatography, and CCK-8. The surface was porous and uniformly thick (average thickness, 48.67 µm)—with good flexibility, long-term slow drug release, and optimal drug concentration—and was biologically safe. The experimental results show that PCL is an ideal controlled-release material for dexamethasone as a drug carrier coating for cochlear implants.
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Affiliation(s)
- Yanjing Luo
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| | - Anning Chen
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| | - Muqing Xu
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| | - Dongxiu Chen
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| | - Jie Tang
- Hearing Research Center, Southern Medical University, Guangzhou, China.,Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China
| | - Dong Ma
- Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou, China
| | - Hongzheng Zhang
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
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19
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Bennion DM, Horne R, Peel A, Reineke P, Henslee A, Kaufmann C, Guymon CA, Hansen MR. Zwitterionic Photografted Coatings of Cochlear Implant Biomaterials Reduce Friction and Insertion Forces. Otol Neurotol 2021; 42:1476-1483. [PMID: 34310554 DOI: 10.1097/mao.0000000000003288] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
HYPOTHESIS Application of photografted zwitterionic coatings to cochlear implant (CI) biomaterials will reduce friction and insertion forces. BACKGROUND Strategies to minimize intracochlear trauma during implantation of an electrode array are critical to optimize outcomes including preservation of residual hearing. To this end, advances in thin-film zwitterionic hydrogel coatings on relevant biomaterials may show promise, in addition to the potential of these materials for decreasing the intracochlear foreign body response. METHODS Using a recently designed one-step process, thin-film coatings derived from zwitterionic sulfobetaine methacrylate (SBMA) were photopolymerized and photografted to the surface of polydimethylsiloxane (PDMS, silastic) samples and also to CI arrays from two manufacturers. Fluorescein staining and scanning electron microscopy with energy-dispersive X-ray spectroscopy verified and characterized the coatings. Tribometry was used to measure the coefficient of friction between uncoated and coated PDMS and synthetic and biological tissues. Force transducer measurements were obtained during insertion of uncoated (n = 9) and coated (n = 9) CI electrode arrays into human cadaveric cochleae. RESULTS SBMA thin-film coating of PDMS resulted in >90% reduction in frictional coefficients with steel, ceramic, and dermal tissue from guinea pigs (p < 0.0001). We employed a novel method for applying covalently bonded, durable, and uniform coating in geographically selective areas at the electrode array portion of the implant. Image analysis confirmed uniform coating of PDMS systems and the CI electrode arrays with SBMA polymer films. During insertion of electrode arrays into human cadaveric cochleae, SBMA coatings reduced maximum force by ∼40% during insertion (p < 0.001), as well as decreasing force variability and the overall work of insertion. CONCLUSION Thin-film SBMA photografted coatings on PDMS and electrode arrays significantly reduce frictional coefficients and insertional forces in cadaveric cochleae. These encouraging findings support that thin-film zwitterionic coating of CI electrode arrays may potentially reduce insertional trauma and thereby promote improved hearing and other long-term outcomes.
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Affiliation(s)
- Douglas M Bennion
- Department of Otolaryngology-Head and Neck Surgery Department of Chemical and Biochemical Engineering, University of Iowa iotaMotion, Inc, Iowa City, Iowa
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Evaluation of Insertion Forces and Cochlea Trauma Following Robotics-Assisted Cochlear Implant Electrode Array Insertion. Otol Neurotol 2021; 41:631-638. [PMID: 32604327 DOI: 10.1097/mao.0000000000002608] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
HYPOTHESIS The objective was to evaluate the effect of cochlear implant (CI) insertion technique on electrode insertion forces and intracochlear trauma. We hypothesize that robotics-assisted insertions will reduce insertion forces and intracochlear trauma compared with manual insertions. BACKGROUND Variability in CI outcomes exists across patients, implant centers, surgeons, and electrode types. While surgical techniques that reduce electrode insertion trauma are well established, insertion trauma remains one contributing factor to variability in CI outcomes. Previous work demonstrates that micromechanically controlled insertion tools reduce both maximum insertion forces and insertion variability compared with manual insertions. METHODS CI electrode insertions were performed either by hand (n = 12) or utilizing a robotics-assisted tool (n = 12) in fresh frozen, human cadaveric cochleae using electrodes from four different CI manufacturers. Electrodes array insertion forces were additionally evaluated in benchtop cochlea models. Following cadaveric insertions, samples were imaged via high resolution x-ray microscopy to evaluate electrode position and intracochlear trauma events based on a modified Eshraghi scale. RESULTS Electrode array insertions performed by robotics-assisted system showed significantly lower insertion forces and variability. Manual electrode array insertions had a significantly higher overall trauma score of 3.1 ± 2.0 compared with 0.9 ± 1.0 for robotics-assisted insertions. Robotics-assisted insertions had higher rate of basilar membrane elevations while manual insertions showed higher rates of severe trauma events. CONCLUSIONS The robotic-assisted insertion system reduced trauma events associated with CI electrode insertions in cadaveric cochleae compared with manual insertions. Surgical devices which help to precisely and more consistently insert electrodes may improve CI outcomes and hearing preservation.
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O'Leary SJ, Choi J, Brady K, Matthews S, Ozdowska KB, Payne M, McLean T, Rousset A, Lo J, Creber N, Tari S, Dowell R, Briggs R. Systemic methylprednisolone for hearing preservation during cochlear implant surgery: A double blinded placebo-controlled trial. Hear Res 2021; 404:108224. [PMID: 33774594 DOI: 10.1016/j.heares.2021.108224] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 01/13/2023]
Abstract
AIM To assess whether a single, peri-operative, high dose of methylprednisolone can improve the preservation of residual acoustic hearing following cochlear implantation (CI). METHODS This was a double blinded placebo-controlled trial, performed in a tertiary academic centre. The hypothesis was that methylprednisolone would improve the preservation of hearing, and lower electrode impedances. Adult patients (18-85 years) with hearing at 85 dB or better at 500 Hz in the ear to be implanted were randomly allocated to either treatment (methylprednisolone, 1g administered intravenously upon induction of anaesthesia) or control (normal saline infusion). As per standard clinical practice, all patients received a routine dose of dexamethasone (8 mg intravenously) on induction of anaesthesia. Implantation was undertaken with a slim and flexible lateral wall electrode via the round window. Surgical technique was routine, with adherence to soft surgical principles. The primary outcome was hearing preservation within 20 dB at 500 Hz, 12 months following cochlear implantation. Secondary outcomes included hearing preservation at 6 weeks and 3 months, monopolar electrode impedance, and Consonant-Vowel-Consonant (CVC) Phoneme scores at 3 and 12 months after surgery. RESULTS Forty-five patients were enrolled into the control group and 48 patients received the steroid. The number of patients achieving hearing preservation at 12 months did not differ significantly between those receiving methylprednisolone treatment and the controls. There were no differences in hearing preservation at any frequency at either 6 weeks or 3 months after implantation. Neither CVC phoneme scores nor electrode impedances differed between the groups. CONCLUSIONS This paper demonstrates that high-dose local steroid injection at surgery was not effective in preventing a loss of residual hearing, improving speech perception, or lowering electrode impedances. The findings were contrary to the experimental literature, and emerging clinical evidence that steroid elution from implant electrodes influences cochlear biology in humans. We found no evidence to support the widely-held practice of administering intravenous steroids in the perioperative period, in an attempt to preserve residual hearing.
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Affiliation(s)
- Stephen J O'Leary
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia; Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, 32 Gisborne St, Melbourne East 3002, Australia.
| | - June Choi
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia; Department of Otorhinolaryngology - Head & Neck Surgery, Ansan Hospital, College of Medicine, Korea University, 123, Jeokgeum-ro (Street), Gojan-dong, Danwon-gu, Ansan-si, Gyeonggi-do 15355, Republic of Korea
| | - Karina Brady
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Sheila Matthews
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Katie Boncza Ozdowska
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Matthew Payne
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Tim McLean
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Alex Rousset
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Jonathon Lo
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Nathan Creber
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Sylvia Tari
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia
| | - Richard Dowell
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia; Department of Audiology and Speech Sciences, University of Melbourne, 550 Swanston St, Carlton 3053, Australia
| | - Robert Briggs
- Department of Surgery - Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne St RVEEH, Melbourne East 3002,Victoria, Australia; Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, 32 Gisborne St, Melbourne East 3002, Australia
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22
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O’Leary S, Briggs R, Gerard JM, Iseli C, Wei BP, Tari S, Rousset A, Bester C. Intraoperative Observational Real-time Electrocochleography as a Predictor of Hearing Loss After Cochlear Implantation: 3 and 12 Month Outcomes. Otol Neurotol 2020; 41:1222-1229. [PMID: 32925842 PMCID: PMC7497893 DOI: 10.1097/mao.0000000000002773] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE A decrease in intracochlear electrocochleographic (ECochG) amplitude during cochlear implantation has been associated with poorer postoperative hearing preservation in several short-term studies. Here, we relate the stability of ECochG during surgery to hearing preservation at 3- and 12-months. METHODS Patients with hearing ≤80-dB HL at 500 Hz were implanted with a slim-straight electrode array. ECochG responses to short, high-intensity, 500-Hz pure tones of alternating polarity were recorded continuously from the apical-most electrode during implantation. No feedback was provided to the surgeon. ECochG amplitude was derived from the difference response, and implantations classified by the presence ("ECochG drop") or absence ("no drop") of a ≥30% reduction in ECochG amplitude during insertion. Residual hearing (relative and absolute) was reported against the ECochG class. RESULTS ECochG was recorded from 109 patients. Of these, interpretable ECochG signals were recorded from 95. Sixty-six of 95 patients had an ECochG drop during implantation. Patients with an ECochG drop had poorer preoperative hearing above 1000 Hz. Hearing preservation (in decibels, relative to preoperative levels and functionally) was significantly poorer at 250-, 500-, and 1000-Hz at 3 months in patients exhibiting an ECochG drop. Twelve-month outcomes were available from 85 patients, with significantly poorer functional hearing, and greater relative and absolute hearing loss from 250 to 1000 Hz, when an ECochG drop had been encountered. CONCLUSION Patients exhibiting ECochG drops during implantation had significantly poorer hearing preservation 12 months later. These observational outcomes support the future development of surgical interventions responsive to real-time intracochlear ECochG. Early intervention to an ECochG drop could potentially lead to prolonged improvements in hearing preservation.
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Affiliation(s)
- Stephen O’Leary
- Department of Surgery—Otolaryngology, University of Melbourne
| | - Robert Briggs
- Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | | | - Claire Iseli
- Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Benjamin P.C. Wei
- Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Sylvia Tari
- Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Alex Rousset
- Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Christo Bester
- Department of Surgery—Otolaryngology, University of Melbourne
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Lee MY, Kim YC, Jang J, Jung JY, Choi H, Jang JH, Choung YH. Dexamethasone delivery for hearing preservation in animal cochlear implant model: continuity, long-term release, and fast release rate. Acta Otolaryngol 2020; 140:713-722. [PMID: 32449405 DOI: 10.1080/00016489.2020.1763457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Background: Clinically, steroids have been used for hearing preservation both topically and systemically during cochlear implantation.Objective: This study compared steroid efficacy for hearing preservation among different types of delivery modes using an animal experiment.Materials and methods: For 76 guinea pigs, topical and systemic delivery methods, four pump types with different infusion rates, delivery durations, and total steroid amounts were used. Threshold changes of 8, 16, and 32 kHz after dummy electrode insertion were evaluated at 1 and 4 weeks and compared among delivery method and pump types. Inflammatory response in the cochlea was histologically compared.Results: For topical delivery groups, long-term release showed advantages in preserving hearing. Systemic delivery groups showed smaller threshold shifts than control group in all frequencies (p > .05). In short-term low dose application, compared to topical delivery, systemic delivery showed advantage in hearing preservation at both time point. However, others fail to show significant difference between two methods. Histologically, inflammatory response in the scala tympani at the basal turn was less in systemic delivery, especially in high dose and long-term.Conclusion and significance: The difference of hearing preservation was not obvious between two delivery methods. Higher dose and longer duration might have advantages in hearing preservation.
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Affiliation(s)
- Min Young Lee
- Department of Otolaryngology, Dankook University School of Medicine, Cheonan, South Korea
| | - Young Cheol Kim
- Department of Otorhinolaryngology, Ajou University School of Medicine, Suwon, South Korea
| | - Jongmoon Jang
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Jae Yun Jung
- Department of Otolaryngology, Dankook University School of Medicine, Cheonan, South Korea
| | - Hongsoo Choi
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Jeong Hun Jang
- Department of Otorhinolaryngology, Ajou University School of Medicine, Suwon, South Korea
| | - Yun-Hoon Choung
- Department of Otorhinolaryngology, Ajou University School of Medicine, Suwon, South Korea
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Comparison of electrode impedance measures between a dexamethasone-eluting and standard Cochlear™ Contour Advance® electrode in adult cochlear implant recipients. Hear Res 2020; 390:107924. [DOI: 10.1016/j.heares.2020.107924] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 02/10/2020] [Accepted: 02/13/2020] [Indexed: 11/22/2022]
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Liebau A, Schilp S, Mugridge K, Schön I, Kather M, Kammerer B, Tillein J, Braun S, Plontke SK. Long-Term in vivo Release Profile of Dexamethasone-Loaded Silicone Rods Implanted Into the Cochlea of Guinea Pigs. Front Neurol 2020; 10:1377. [PMID: 32038458 PMCID: PMC6987378 DOI: 10.3389/fneur.2019.01377] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 12/13/2019] [Indexed: 11/29/2022] Open
Abstract
Glucocorticoids are used intra-operatively in cochlear implant surgeries to reduce the inflammatory reaction caused by insertion trauma and the foreign body response against the electrode carrier after cochlear implantation. To prevent higher systemic concentrations of glucocorticoids that might cause undesirable systemic side effects, the drug should be applied locally. Since rapid clearance of glucocorticoids occurs in the inner ear fluid spaces, sustained application is supposedly more effective in suppressing foreign body and tissue reactions and in preserving neuronal structures. Embedding of the glucocorticoid dexamethasone into the cochlear implant electrode carrier and its continuous release may solve this problem. The aim of the present study was to examine how dexamethasone concentrations in the electrode carrier influence drug levels in the perilymph at different time points. Silicone rods were implanted through a cochleostomy into the basal turn of the scala tympani of guinea pigs. The silicone rods were loaded homogeneously with 0.1, 1, and 10% concentrations of dexamethasone. After implantation, dexamethasone concentrations in perilymph and cochlear tissue were measured at several time points over a period of up to 7 weeks. The kinetic was concentration-dependent and showed an initial burst release in the 10%- and the 1%-dexamethasone-loaded electrode carrier dummies. The 10%-loaded electrode carrier resulted in a more elevated and longer lasting burst release than the 1%-loaded carrier. Following this initial burst release phase, sustained dexamethasone levels of about 60 and 100 ng/ml were observed in the perilymph for the 1 and 10% loaded rods, respectively, during the remainder of the observation time. The 0.1% loaded carrier dummy achieved very low perilymph drug levels of about 0.5 ng/ml. The cochlear tissue drug concentration shows a similar dynamic to the perilymph drug concentration, but only reaches about 0.005–0.05% of the perilymph drug concentration. Dexamethasone can be released from silicone electrode carrier dummies in a controlled and sustained way over a period of several weeks, leading to constant drug concentrations in the scala tympani perilymph. No accumulation of dexamethasone was observed in the cochlear tissue. In consideration of experimental studies using similar drug depots and investigating physiological effects, an effective dose range between 50 and 100 ng/ml after burst release is suggested for the CI insertion trauma model.
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Affiliation(s)
- Arne Liebau
- Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
| | | | | | - Ilona Schön
- Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Michel Kather
- Center for Biological Systems Analysis ZBSA, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Hermann Staudinger Graduate School, University of Freiburg, Freiburg, Germany
| | - Bernd Kammerer
- Center for Biological Systems Analysis ZBSA, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | | | | | - Stefan K Plontke
- Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
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Choong JK, Hampson AJ, Brody KM, Lo J, Bester CW, Gummer AW, Reynolds NP, O'Leary SJ. Nanomechanical mapping reveals localized stiffening of the basilar membrane after cochlear implantation. Hear Res 2019; 385:107846. [PMID: 31786442 DOI: 10.1016/j.heares.2019.107846] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 11/02/2019] [Accepted: 11/10/2019] [Indexed: 01/12/2023]
Abstract
Cochlear implantation leads to many structural changes within the cochlea which can impair residual hearing. In patients with preserved low-frequency hearing, a delayed hearing loss can occur weeks-to-years post-implantation. We explore whether stiffening of the basilar membrane (BM) may be a contributory factor in an animal model. Our objective is to map changes in morphology and Young's modulus of basal and apical areas of the BM after cochlear implantation, using quantitative nanomechanical atomic force microscopy (QNM-AFM) after cochlear implant surgery. Cochlear implantation was undertaken in the guinea pig, and the BM was harvested at four time-points: 1 day, 14 days, 28 days and 84 days post-implantation for QNM-AFM analysis. Auditory brainstem response thresholds were determined prior to implantation and termination. BM tissue showed altered morphology and a progressive increase in Young's modulus, mainly in the apex, over time after implantation. BM tissue from the cochlear base demonstrated areas of extreme stiffness which are likely due to micro-calcification on the BM. In conclusion, stiffening of the BM after cochlear implantation occurs over time, even at sites far apical to a cochlear implant.
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Affiliation(s)
- Jessica K Choong
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Amy J Hampson
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Kate M Brody
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Jonathon Lo
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Christofer W Bester
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Strasse 5, 72076, Tübingen, Germany
| | - Nicholas P Reynolds
- ARC Training Centre for Biodevices, Swinburne University of Technology, Hawthorn, Australia; Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Australia.
| | - Stephen J O'Leary
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia.
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Ahmadi N, Gausterer JC, Honeder C, Mötz M, Schöpper H, Zhu C, Saidov N, Gabor F, Arnoldner C. Long-term effects and potential limits of intratympanic dexamethasone-loaded hydrogels combined with dexamethasone-eluting cochlear electrodes in a low-insertion trauma Guinea pig model. Hear Res 2019; 384:107825. [PMID: 31669876 DOI: 10.1016/j.heares.2019.107825] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 09/07/2019] [Accepted: 10/16/2019] [Indexed: 12/11/2022]
Abstract
Cochlear implantation has become the most effective hearing restoration method and is one of the great advances in modern medicine. Early implants have been continuously developed into more efficient devices, and electro-acoustic stimulation is increasingly expanding the indication criteria for cochlear implants to patients with more residual hearing. Therefore, protecting the cochlear structures and maintaining its intrinsic capacities like residual hearing has become more important than ever before. In the present study, we aimed to assess the long-term protective effects of a dexamethasone-eluting electrode combined with the preoperative intratympanic application of a dexamethasone-loaded thermoreversible hydrogel in a cochlear implant guinea pig model. 40 normal-hearing animals were equally randomized into a control group receiving an unloaded hydrogel and a non-eluting electrode, a group receiving a dexamethasone-loaded hydrogel and a non-eluting electrode, a group receiving an unloaded hydrogel and a dexamethasone-eluting electrode and a group receiving both a dexamethasone-loaded hydrogel and a dexamethasone-eluting electrode. Residual hearing and impedances were investigated during a period of 120 days. Tissue response and histological changes of cochlear structures were analyzed at the end of the experiments. Treatment with dexamethasone did not show a significant protective effect on residual hearing independent of treatment group. Although the majority of the cochleae didn't exhibit any signs of electrode insertion trauma, a small degree of tissue response could be observed in all animals without a significant difference between the groups. Foreign body giant cells and osteogenesis were significantly associated with tissue response. Hair cells, synapsin-1-positive cells and spiral ganglion cells were preserved in all study groups. Cochlear implantation using a dexamethasone-eluting electrode alone and in combination with a dexamethasone-loaded hydrogel significantly protected auditory nerve fibers on day 120. Post-implantation impedances were equal across study groups and remained stable over the duration of the experiment. In this study we were able to show that use of a dexamethasone-eluting electrode alone and in combination with preoperative application of dexamethasone-loaded hydrogel significantly protects auditory nerve fibers. Furthermore, we have shown that a cochlear implantation-associated hearing threshold shift and tissue response may not be completely prevented by the sole application of dexamethasone.
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Affiliation(s)
- Navid Ahmadi
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria.
| | - Julia Clara Gausterer
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Vienna, Austria.
| | - Clemens Honeder
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria.
| | - Marlene Mötz
- Department of Pathobiology, Institute of Anatomy, Histology and Embryology, University of Veterinary Medicine Vienna, Austria.
| | - Hanna Schöpper
- Department of Pathobiology, Institute of Anatomy, Histology and Embryology, University of Veterinary Medicine Vienna, Austria.
| | - Chengjing Zhu
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria.
| | - Nodir Saidov
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria.
| | - Franz Gabor
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Vienna, Austria.
| | - Christoph Arnoldner
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria.
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Honeder C, Zhu C, Gausterer JC, Schöpper H, Ahmadi N, Saidov N, Nieratschker M, Gabor F, Arnoldner C. Sustained-Release Triamcinolone Acetonide Hydrogels Reduce Hearing Threshold Shifts in a Model for Cochlear Implantation with Hearing Preservation. Audiol Neurootol 2019; 24:237-244. [PMID: 31574511 DOI: 10.1159/000501331] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/04/2019] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION In recent years, the preservation of residual hearing has become a major factor in patients undergoing cochlear implantation (CI). In studies attempting to pharmaceutically improve hearing preservation rates, glucocorticoids (GCs) applied perioperatively in many institutions have emerged as a promising treatment regimen. Although dexamethasone is most commonly used and has been applied successfully by various research groups, recently pharmacological properties have been reported to be relatively unsuitable for topical delivery to the inner ear. Consequently other glucocorticoids merit further evaluation. The aim of this study was therefore to evaluate the otoprotective effects of the topical application of a sustained-release triamcinolone acetonide (TAAC) hydrogel in CI with hearing preservation. METHODS Normal-hearing pigmented guinea pigs were randomized into a group receiving a single dose of a 6% TAAC poloxamer 407 hydrogel, a group receiving a 30% TAAC hydrogel and a control group. All hydrogel applications were performed 1 day prior to CI. After a cochleostomy was drilled, a specifically designed silicone electrode was inserted into the scala tympani for 5 mm. Frequency-specific compound action potentials of the auditory nerve (0.5-32 kHz) were measured pre- and directly postoperatively as well as on days 3, 7, 14, 21, and 28. Finally, temporal bones were harvested for histological evaluation. RESULTS Application of the TAAC hydrogels resulted in significantly reduced hearing threshold shifts in low, middle and high frequencies and improved spiral ganglion cell survival in the second turn of the cochlea. Outer hair cell numbers in the basal and second turn of the cochlea were slightly reduced after TAAC application. CONCLUSION In summary, we were able to demonstrate functional benefits of a single preoperative application of a TAAC hydrogel in a guinea pig model for CI, which persisted until the end of the observational period, that is, 28 days after surgery.
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Affiliation(s)
- Clemens Honeder
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Chengjing Zhu
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Julia Clara Gausterer
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Vienna, Austria
| | - Hanna Schöpper
- Department of Pathobiology, Institute of Anatomy, Histology and Embryology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Navid Ahmadi
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Nodir Saidov
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Michael Nieratschker
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Franz Gabor
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Vienna, Austria,
| | - Christoph Arnoldner
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
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Glucocorticoid for Hearing Preservation After Cochlear Implantation: A Systemic Review and Meta-analysis of Animal Studies. Otol Neurotol 2019; 40:1178-1185. [DOI: 10.1097/mao.0000000000002383] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Cochlear Glucocorticoid Receptor and Serum Corticosterone Expression in a Rodent Model of Noise-induced Hearing Loss: Comparison of Timing of Dexamethasone Administration. Sci Rep 2019; 9:12646. [PMID: 31477769 PMCID: PMC6718671 DOI: 10.1038/s41598-019-49133-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 08/14/2019] [Indexed: 12/20/2022] Open
Abstract
Glucocorticoid (GC) is a steroid hormone secreted from the adrenal cortex in response to stress, which acts by binding to cytoplasmic glucocorticoid receptors (GRs). Dexamethasone (DEX) is a synthetic GC exhibiting immunosuppressive effects in both human and rodent models of hearing loss. While clinical evidence has shown the effectiveness of DEX for treatment of various inner ear diseases, its mechanisms of action and the optimal timing of treatment are not well understood. In the present study, intergroup comparisons were conducted based on the time point of treatment with DEX: (1) pretreatment; (2) posttreatment; and (3) pre&post-noise. The pre&post DEX treatment group showed a significant improvement in threshold shift at 1 day post-noise exposure as compared to the TTS (transient threshold shift)-only group at 8 and 16 kHz. Both TTS and PTS (permanent threshold shift) significantly reduced cochlear GR mRNA expression and increased serum corticosterone and cochlear inflammatory cytokines. The pre&post DEX treatment group showed a significant decrease in serum corticosterone level as compared to other DEX treatment groups and TTS-treated group at 3 days after acoustic trauma. Our results suggest that the timing of DEX administration differentially modulates systemic steroid levels, GR expression and cochlear cytokine expression.
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Ma Y, Wise AK, Shepherd RK, Richardson RT. New molecular therapies for the treatment of hearing loss. Pharmacol Ther 2019; 200:190-209. [PMID: 31075354 DOI: 10.1016/j.pharmthera.2019.05.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022]
Abstract
An estimated 466 million people suffer from hearing loss worldwide. Sensorineural hearing loss is characterized by degeneration of key structures of the sensory pathway in the cochlea such as the sensory hair cells, the primary auditory neurons and their synaptic connection to the hair cells - the ribbon synapse. Various strategies to protect or regenerate these sensory cells and structures are the subject of intensive research. Yet despite recent advances in our understandings of the capacity of the cochlea for repair and regeneration there are currently no pharmacological or biological interventions for hearing loss. Current research focusses on localized cochlear drug, gene and cell-based therapies. One of the more promising drug-based therapies is based on neurotrophic factors for the repair of the ribbon synapse after noise exposure, as well as preventing loss of primary auditory neurons and regrowth of the auditory neuron fibers after severe hearing loss. Drug therapy delivery technologies are being employed to address the specific needs of neurotrophin and other therapies for hearing loss that include the need for high doses, long-term delivery, localised or cell-specific targeting and techniques for their safe and efficacious delivery to the cochlea. Novel biomaterials are enabling high payloads of drugs to be administered to the cochlea with subsequent slow-release properties that are proving to be beneficial for treating hearing loss. In parallel, new gene therapy technologies are addressing the need for cell specificity and high efficacy for the treatment of both genetic and acquired hearing loss with promising reports of hearing recovery. Some biomaterials and cell therapies are being used in conjunction with the cochlear implant ensuring therapeutic benefit to the primary neurons during electrical stimulation. This review will introduce the auditory system, hearing loss and the potential for repair and regeneration in the cochlea. Drug delivery to the cochlea will then be reviewed, with a focus on new biomaterials, gene therapy technologies, cell therapy and the use of the cochlear implant as a vehicle for drug delivery. With the current pre-clinical research effort into therapies for hearing loss, including clinical trials for gene therapy, the future for the treatment for hearing loss is looking bright.
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Affiliation(s)
- Yutian Ma
- Bionics Institute, East Melbourne, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Australia; University of Melbourne, Department of Chemical Engineering, Parkville, Victoria, Australia
| | - Andrew K Wise
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Robert K Shepherd
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Rachael T Richardson
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia.
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Single Intravenous High Dose Administration of Prednisolone Has No Influence on Postoperative Impedances in the Majority of Cochlear Implant Patients. Otol Neurotol 2018; 39:e1002-e1009. [DOI: 10.1097/mao.0000000000002033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Creber NJ, Eastwood HT, Hampson AJ, Tan J, O'Leary SJ. A comparison of cochlear distribution and glucocorticoid receptor activation in local and systemic dexamethasone drug delivery regimes. Hear Res 2018; 368:75-85. [DOI: 10.1016/j.heares.2018.03.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/10/2018] [Accepted: 03/15/2018] [Indexed: 12/26/2022]
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Frisina RD, Budzevich M, Zhu X, Martinez GV, Walton JP, Borkholder DA. Animal model studies yield translational solutions for cochlear drug delivery. Hear Res 2018; 368:67-74. [PMID: 29793764 PMCID: PMC6165691 DOI: 10.1016/j.heares.2018.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/17/2018] [Accepted: 05/03/2018] [Indexed: 11/18/2022]
Abstract
The field of hearing and deafness research is about to enter an era where new cochlear drug delivery methodologies will become more innovative and plentiful. The present report provides a representative review of previous studies where efficacious results have been obtained with animal models, primarily rodents, for protection against acute hearing loss such as acoustic trauma due to noise overexposure, antibiotic use and cancer chemotherapies. These approaches were initiated using systemic injections or oral administrations of otoprotectants. Now, exciting new options for local drug delivery, which opens up the possibilities for utilization of novel otoprotective drugs or compounds that might not be suitable for systemic use, or might interfere with the efficacious actions of chemotherapeutic agents or antibiotics, are being developed. These include interesting use of nanoparticles (with or without magnetic field supplementation), hydrogels, cochlear micropumps, and new transtympanic injectable compounds, sometimes in combination with cochlear implants.
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Affiliation(s)
- R D Frisina
- Dept. Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Dept. Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Dept. Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA.
| | - M Budzevich
- Small Animal Imaging Lab, Moffitt Cancer Center, Tampa, FL, USA
| | - X Zhu
- Dept. Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Dept. Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - G V Martinez
- Small Animal Imaging Lab, Moffitt Cancer Center, Tampa, FL, USA
| | - J P Walton
- Dept. Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Dept. Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - D A Borkholder
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA
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Yamahara K, Nishimura K, Ogita H, Ito J, Nakagawa T, Furuta I, Kita T, Omori K, Yamamoto N. Hearing preservation at low frequencies by insulin-like growth factor 1 in a guinea pig model of cochlear implantation. Hear Res 2018; 368:92-108. [DOI: 10.1016/j.heares.2018.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 03/30/2018] [Accepted: 07/04/2018] [Indexed: 12/17/2022]
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Chambers S, Newbold C, Stathopoulos D, Needham K, Miller C, Risi F, Enke YL, Timbol G, Cowan R. Protecting against electrode insertion trauma using dexamethasone. Cochlear Implants Int 2018; 20:1-11. [PMID: 30126345 DOI: 10.1080/14670100.2018.1509531] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To compare the benefits of a dexamethasone-eluting array for hearing preservation and cochlear histopathology in low trauma (soft-surgery) and high trauma models of cochlear implant surgery. METHODS Adult guinea pigs were implanted with an intra-cochlear array using two different surgical procedures: either a soft-surgery approach or following generation of electrode insertion trauma (high trauma). Two methods of dexamethasone delivery were evaluated: elution from an electrode array alone, and elution from a cochlear implant electrode array in combination with a pre-operative systemic injection. All electrode arrays were implanted for a period of 4 weeks. Outcome measures at 4 weeks post-implantation included auditory brainstem response (ABR) thresholds, histological analysis of spiral ganglion neuron density, fibrotic tissue, new bone growth, and cochlear damage. RESULTS Animals exposed to high surgical trauma showed greater hearing loss than those in the low trauma model, irrespective of the presence of dexamethasone. Whilst the area of intra-cochlear fibrotic tissue growth post-implantation was also independent of dexamethasone administration, new bone growth was significantly reduced in its presence. Our high trauma model effectively obliterated the organ of Corti and significantly reduced spiral ganglion neuron densities in the lower basal turn. This trauma-induced reduction in spiral ganglion neuron survival decreased with the inclusion of a dexamethasone-eluting array. A pre-operative systemic injection of dexamethasone did not significantly improve any outcome measures beyond those provided with a dexamethasone-eluting array alone. CONCLUSION Dexamethasone-eluting intra-cochlear arrays may inhibit osteoneogenesis, and reduce spiral ganglion neuron loss following traumatic cochlear implantation.
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Affiliation(s)
- Scott Chambers
- a The HEARing CRC , Carlton , Australia.,b Department of Audiology and Speech Pathology , The University of Melbourne , Carlton , Australia
| | - Carrie Newbold
- a The HEARing CRC , Carlton , Australia.,b Department of Audiology and Speech Pathology , The University of Melbourne , Carlton , Australia.,c Otolaryngology, Department of Surgery , The University of Melbourne , East Melbourne , Australia
| | - Dimitra Stathopoulos
- a The HEARing CRC , Carlton , Australia.,b Department of Audiology and Speech Pathology , The University of Melbourne , Carlton , Australia
| | - Karina Needham
- a The HEARing CRC , Carlton , Australia.,b Department of Audiology and Speech Pathology , The University of Melbourne , Carlton , Australia.,c Otolaryngology, Department of Surgery , The University of Melbourne , East Melbourne , Australia
| | - Chris Miller
- d Cochlear Ltd at Macquarie University , Sydney , NSW , Australia
| | - Frank Risi
- d Cochlear Ltd at Macquarie University , Sydney , NSW , Australia
| | - Ya Lang Enke
- d Cochlear Ltd at Macquarie University , Sydney , NSW , Australia
| | - Godofredo Timbol
- d Cochlear Ltd at Macquarie University , Sydney , NSW , Australia
| | - Robert Cowan
- a The HEARing CRC , Carlton , Australia.,b Department of Audiology and Speech Pathology , The University of Melbourne , Carlton , Australia
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Creber NJ, Eastwood HT, Hampson AJ, Tan J, O'Leary SJ. Adjuvant agents enhance round window membrane permeability to dexamethasone and modulate basal to apical cochlear gradients. Eur J Pharm Sci 2018; 126:69-81. [PMID: 30107228 DOI: 10.1016/j.ejps.2018.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/22/2018] [Accepted: 08/09/2018] [Indexed: 01/09/2023]
Abstract
Glucocorticoids have direct anti-inflammatory, anti-oxidant and anti-apoptotic effects on cochlear hair cells. Cochlear glucocorticoid therapy has gained particular attention for its ability to enhance the protection of residual hearing following hearing preservation cochlear implantation. Local drug delivery methods achieve high drug concentrations within the inner ear fluids but are reliant upon diffusion across the round window membrane. Diffusion has been shown to demonstrate large individual variability. This study explores the role of "adjuvant agents", which when administered with glucocorticoids, enhance inner ear absorption and distribution. Guinea pig cochleae were administered either dexamethasone alone or in combination with hyaluronic acid, histamine, or combination histamine and hyaluronic acid, targeted at the round window membrane. Control subjects received saline. Perilymph was sampled from the cochlear apex, and basal to apical dexamethasone concentrations recorded with mass spectroscopy. Cochleae were harvested, and immunohistochemistry employed to explore dexamethasone tissue penetration and distribution. Basal to apical gradients were observed along the scala tympani, with higher dexamethasone concentrations observed at the cochlear base. Gradients were more pronounced and uniform when administered on a hyaluronic acid sponge, while histamine increased absolute concentrations reaching the inner ear. Tissue penetration correlated with perilymph concentration. Our results demonstrate that adjuvant agents can be employed to enhance dexamethasone absorption and distribution in the inner ear, thus proposing therapeutic strategies that may enhance steroid facilitated hearing protection.
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Affiliation(s)
- Nathan J Creber
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne 3002, Australia.
| | - Hayden T Eastwood
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne 3002, Australia
| | - Amy J Hampson
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne 3002, Australia
| | - Justin Tan
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne 3002, Australia
| | - Stephen J O'Leary
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne 3002, Australia; Royal Victorian Eye and Ear Hospital, East Melbourne 3002, Australia
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A cochlear implant loaded with dexamethasone and coated with hyaluronic acid to inhibit fibroblast adhesion and proliferation. J Drug Deliv Sci Technol 2018. [DOI: 10.1016/j.jddst.2018.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Effects of dexamethasone on intracochlear inflammation and residual hearing after cochleostomy: A comparison of administration routes. PLoS One 2018; 13:e0195230. [PMID: 29601595 PMCID: PMC5877881 DOI: 10.1371/journal.pone.0195230] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 03/06/2018] [Indexed: 12/20/2022] Open
Abstract
Preservation of residual hearing after cochlear implant is an important issue with regards to hearing performance. Various methods of steroid administration have been widely used in clinical practice to reduce inflammation and preserve residual hearing. Here we compare the effect of different routes of dexamethasone administration on intracochlear inflammation and residual hearing in guinea pig ears. Dexamethasone was delivered into the guinea pigs either through intracochlear, intratympanic or systemic route. The intracochlear concentration of dexamethasone, residual hearing, inflammatory cytokines and histopathologic changes were evaluated over time. A higher intracochlear dexamethasone concentration was observed after intracochlear administration than through the other routes. Residual hearing was better preserved with local dexamethasone administration as was supported by the reduced inflammatory cytokines, more hair cell survival and less severe intracochlear fibrosis and ossification concurrently seen in the local delivery group than in the systemic group. The results demonstrate that local dexamethasone delivery can reduce intracochlear inflammation and preserve residual hearing better than in systemically administered dexamethasone.
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Lo J, Bester C, Collins A, Newbold C, Hampson A, Chambers S, Eastwood H, O'Leary S. Intraoperative force and electrocochleography measurements in an animal model of cochlear implantation. Hear Res 2018; 358:50-58. [DOI: 10.1016/j.heares.2017.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/07/2017] [Accepted: 11/06/2017] [Indexed: 12/15/2022]
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Kuthubutheen J, Joglekar S, Smith L, Friesen L, Smilsky K, Millman T, Ng A, Shipp D, Coates H, Arnoldner C, Nedzelski J, Chen J, Lin V. The Role of Preoperative Steroids for Hearing Preservation Cochlear Implantation: Results of a Randomized Controlled Trial. Audiol Neurootol 2018; 22:292-302. [DOI: 10.1159/000485310] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 11/14/2017] [Indexed: 12/22/2022] Open
Abstract
Objectives: To determine whether preoperative steroids can improve hearing outcomes in cochlear implantation (CI). Methods: This is a randomized controlled trial involving 30 postlingual deaf CI patients. Subjects had preoperative thresholds of better than or equal to 80 dB at 125 and 250 Hz, and better than or equal to 90 dB at 500 and 1,000 Hz. The subjects were randomized to a control group, an oral steroid group (receiving 1 mg/kg/day of prednisolone for 6 days prior to surgery), or a transtympanic steroid group (receiving a single dose of 0.5 mL of 10 mg/mL dexamethasone at 24 h prior to surgery). Results: The subjects receiving transtympanic steroids had a significant decrease in the pure tone average over 3 months compared to the control and oral steroid group, which persisted over 12 months (p < 0.05). Conclusion: A single dose of preoperative transtympanic steroids prior to CI appears to have a beneficial effect, at least in the short term, with minimal effects seen in the longer term.
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Electrode Impedance Fluctuations as a Biomarker for Inner Ear Pathology After Cochlear Implantation. Otol Neurotol 2017; 38:1433-1439. [DOI: 10.1097/mao.0000000000001589] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Perilymph pharmacokinetics of marker applied through a cochlear implant in guinea pigs. PLoS One 2017; 12:e0183374. [PMID: 28817653 PMCID: PMC5560723 DOI: 10.1371/journal.pone.0183374] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/02/2017] [Indexed: 11/26/2022] Open
Abstract
Patients undergoing cochlear implantation could benefit from a simultaneous application of drugs into the ear, helping preserve residual low-frequency hearing and afferent nerve fiber populations. One way to apply drugs is to incorporate a cannula into the implant, through which drug solution is driven. For such an approach, perilymph concentrations achieved and the distribution in the ear over time have not previously been documented. We used FITC-labeled dextran as a marker, delivering it into perilymph of guinea pigs at 10 or 100 nL/min though a cannula incorporated into a cochlear implant with the outlet in the mid basal turn. After injections of varying duration (2 hours, 1 day or 7 days) perilymph was collected from the cochlear apex using a sequential sampling technique, allowing dextran levels and gradients along scala tympani to be quantified. Data were interpreted quantitatively using computer simulations of the experiments. For injections of 2 hours duration, dextran levels were critically influenced by the presence or absence of fluid leakage at the cochleostomy site. When the cochleostomy was fluid-tight, substantially higher perilymph levels were achieved at the injection site, with concentration declining along scala tympani towards the apex. Contrary to expectations, large dextran gradients along scala tympani persisted after 24 hours of sustained injection and were still present in some animals after 7 days injection. Functional changes associated with implantation and dextran delivery, and the histological state of the implant and cannula were also documented. The persistent longitudinal gradients of dextan along the ear were not readily explained by computer simulations of the experiments based on prior pharmacokinetic data. One explanation is that inner ear pharmacokinetics are altered in the period after cochlear implantation, possibly by a permeabilization of the blood-labyrinth barrier as part of the immune response to the implant.
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The Effect of Systemic Steroid on Hearing Preservation After Cochlear Implantation via Round Window Approach: A Guinea Pig Model. Otol Neurotol 2017; 38:962-969. [DOI: 10.1097/mao.0000000000001453] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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47
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Defining the Hook Region Anatomy of the Guinea Pig Cochlea for Modeling of Inner Ear Surgery. Otol Neurotol 2017; 38:e179-e187. [DOI: 10.1097/mao.0000000000001446] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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The effect of systemic lipoic acid on hearing preservation after cochlear implantation via the round window approach: A guinea pig model. Eur J Pharmacol 2017; 799:67-72. [PMID: 28159538 DOI: 10.1016/j.ejphar.2017.01.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 01/27/2017] [Accepted: 01/30/2017] [Indexed: 01/01/2023]
Abstract
The present study aimed to evaluate the effects of systemic lipoic acid on hearing preservation after cochlear implantation. Twelve Dunkin-Hartley guinea pigs were randomly divided into two groups: the control group and the lipoic acid group. Animals in the lipoic acid group received lipoic acid intraperitoneally for 4 weeks. A sterilised silicone electrode-dummy was inserted through the round window to a depth of approximately 5 mm. The hearing level was measured using auditory brainstem responses (ABRs) prior to electrode-dummy insertion, and at 4 days and 1, 2, 3 and 4 weeks after electrode-dummy insertion. The threshold shift was defined as the difference between the pre-operative threshold and each of the post-operative thresholds. The cochleae were examined histologically 4 weeks after electrode-dummy insertion. Threshold shifts changed with frequency but not time. At 2kHz, ABR threshold shifts were statistically significantly lower in the lipoic acid group than the control group. At 8, 16 and 32kHz, there was no significant difference in the ABR threshold shift between the two groups. Histologic review revealed less intracochlear fibrosis along the electrode-dummy insertion site in the lipoic acid group than in the control group. The spiral ganglion cell densities of the basal, middle and apical turns were significantly higher in the lipoic acid group compared with the control group. Therefore, systemic lipoic acid administration appears to effectively preserve hearing at low frequencies in patients undergoing cochlear implantation. These effects may be attributed to the protection of spiral ganglion cells and prevention of intracochlear fibrosis.
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Rah YC, Lee MY, Kim SH, Kim DH, Eastwood H, O'Leary SJ, Lee JH. Extended use of systemic steroid is beneficial in preserving hearing in guinea pigs after cochlear implant. Acta Otolaryngol 2016; 136:1213-1219. [PMID: 27466708 DOI: 10.1080/00016489.2016.1206965] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
CONCLUSION Seven-day administration of systemic steroids was more effective in preserving hearing for 12 weeks after cochlear implantation (CI) than a 3-day delivery. OBJECTIVES To determine the effectiveness of extended delivery of systemic steroids to preserve hearing in guinea pigs after CI. METHODS Dexamethasone (4 mg/ml) was delivered parenterally via a mini-osmotic pump for either 3 or 7 days. A dummy CI electrode was inserted via cochleostomy approach in 8-week-old guinea pigs. Auditory thresholds were assessed from tone burst auditory brainstem responses (2, 8, 16, 24, and 32 kHz) at 1 day prior to CI, and 1, 4, and 12 weeks after implantation. Histologic evaluation of the cochleae was carried out. RESULTS No differences were observed in hearing thresholds among groups before CI. Significant hearing preservation was achieved at 8, 16, 24, and 32 kHz only in the 7-day infusion group compared with the control group at 1 week after CI. The same trend was maintained at 4 weeks (16, 24 kHz) and 12 weeks (16, 24, and 32 kHz). Histologic review of the 7-day infusion group revealed less fibrosis and ossification in the scala tympani and the preservation of more spiral ganglion cells, compared with the control group.
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Honeder C, Zhu C, Schöpper H, Gausterer JC, Walter M, Landegger LD, Saidov N, Riss D, Plasenzotti R, Gabor F, Arnoldner C. Effects of sustained release dexamethasone hydrogels in hearing preservation cochlear implantation. Hear Res 2016; 341:43-49. [PMID: 27519654 DOI: 10.1016/j.heares.2016.08.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 06/28/2016] [Accepted: 08/08/2016] [Indexed: 01/12/2023]
Abstract
It has been shown that glucocorticoids reduce the hearing threshold shifts associated with cochlear implantation. Previous studies evaluated the administration of glucocorticoids immediately before surgery or the repeated pre- or perioperative systemic application of glucocorticoids. The aim of this study was to evaluate the effects of a sustained release dexamethasone hydrogel in hearing preservation cochlear implantation. To address this issue, a guinea pig model of cochlear implantation was used. 30 normal hearing pigmented guinea pigs were randomized into a group receiving a single dose of a dexamethasone/poloxamer407 hydrogel one day prior to surgery, a second group receiving the hydrogel seven days prior to surgery and a control group. A silicone cochlear implant electrode designed for the use in guinea pigs was inserted to a depth of 5 mm through a cochleostomy. Compound action potentials of the auditory nerve (frequency range 0.5-32 kHz) were measured preoperatively, directly postoperatively and on postoperative days 3, 7, 14, 21 and 28. Following the last audiometry, temporal bones were harvested and histologically evaluated. Dexamethasone hydrogel application one day prior to surgery resulted in significantly reduced hearing threshold shifts at low, middle and high frequencies measured at postoperative day 28 (p < 0.05). Application of the hydrogel seven days prior to surgery did not show such an effect. Dexamethasone application one day prior to surgery resulted in increased outer hair cell counts in the cochlear apex and in reduced spiral ganglion cell counts in the basal and middle turn of the cochlea, a finding that was associated with a higher rate of electrode translocation in this group. In this study, we were able to demonstrate functional benefits of a single preoperative intratympanic application of a sustained release dexamethasone hydrogel in a guinea pig model of cochlear implantation.
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Affiliation(s)
- Clemens Honeder
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Chengjing Zhu
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Hanna Schöpper
- Department of Pathobiology, Institute of Anatomy, Histology and Embryology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Julia Clara Gausterer
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Vienna, Austria
| | - Manuel Walter
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | | | - Nodir Saidov
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Dominik Riss
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Roberto Plasenzotti
- Department of Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Franz Gabor
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Vienna, Austria
| | - Christoph Arnoldner
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria.
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