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Waring NA, Chern A, Vilarello BJ, Cheng YS, Zhou C, Lang JH, Olson ES, Nakajima HH. Hampshire Sheep as a Large-Animal Model for Cochlear Implantation. J Assoc Res Otolaryngol 2024; 25:277-284. [PMID: 38622382 PMCID: PMC11150341 DOI: 10.1007/s10162-024-00946-1] [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: 09/01/2023] [Accepted: 03/28/2024] [Indexed: 04/17/2024] Open
Abstract
BACKGROUND Sheep have been proposed as a large-animal model for studying cochlear implantation. However, prior sheep studies report that the facial nerve (FN) obscures the round window membrane (RWM), requiring FN sacrifice or a retrofacial opening to access the middle-ear cavity posterior to the FN for cochlear implantation. We investigated surgical access to the RWM in Hampshire sheep compared to Suffolk-Dorset sheep and the feasibility of Hampshire sheep for cochlear implantation via a facial recess approach. METHODS Sixteen temporal bones from cadaveric sheep heads (ten Hampshire and six Suffolk-Dorset) were dissected to gain surgical access to the RWM via an extended facial recess approach. RWM visibility was graded using St. Thomas' Hospital (STH) classification. Cochlear implant (CI) electrode array insertion was performed in two Hampshire specimens. Micro-CT scans were obtained for each temporal bone, with confirmation of appropriate electrode array placement and segmentation of the inner ear structures. RESULTS Visibility of the RWM on average was 83% in Hampshire specimens and 59% in Suffolk-Dorset specimens (p = 0.0262). Hampshire RWM visibility was Type I (100% visibility) for three specimens and Type IIa (> 50% visibility) for seven specimens. Suffolk-Dorset RWM visibility was Type IIa for four specimens and Type IIb (< 50% visibility) for two specimens. FN appeared to course more anterolaterally in Suffolk-Dorset specimens. Micro-CT confirmed appropriate CI electrode array placement in the scala tympani without apparent basilar membrane rupture. CONCLUSIONS Hampshire sheep appear to be a suitable large-animal model for CI electrode insertion via an extended facial recess approach without sacrificing the FN. In this small sample, Hampshire specimens had improved RWM visibility compared to Suffolk-Dorset. Thus, Hampshire sheep may be superior to other breeds for ease of cochlear implantation, with FN and facial recess anatomy more similar to humans.
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Affiliation(s)
- Nicholas A Waring
- Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY, USA
| | - Alexander Chern
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY, USA
| | - Brandon J Vilarello
- Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY, USA
| | - Yew Song Cheng
- Department of Otolaryngology-Head & Neck Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Chaoqun Zhou
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY, USA
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Jeffrey H Lang
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elizabeth S Olson
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY, USA.
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
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Olivares-Hernández R, Riaño-Umbarila L, Becerril B, Alagón A, Vázquez-López H. Pharmacokinetic evaluation of a single chain antibody fragment against scorpion toxins in sheep. Toxicon 2024; 242:107691. [PMID: 38522587 DOI: 10.1016/j.toxicon.2024.107691] [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: 10/29/2023] [Revised: 03/04/2024] [Accepted: 03/18/2024] [Indexed: 03/26/2024]
Abstract
A key aspect during the development of antivenoms is the evaluation of the efficiency and security of the therapeutic molecules. In this work, we report the pharmacokinetic analysis of a neutralizing single chain antibody fragment named LR (scFv LR) where three sheep were used as a large animal model. The animals were injected through i.v. route with 2 mg of scFv LR. Blood samples were drawn every minute within the first 15 min, the sampling continues at 20, 25, 30, 45, 60, 90, 120 min, subsequently at 1-h intervals, 3, 4, 5, 6 h, two more samples at 9 and 12 h and, two more samples at 24 and 48 h and finally at one-day intervals during 4 days. scFv LR levels were measured from blood serum and urine samples by an ELISA. The pharmacokinetics of the experimental data was analyzed using the three-exponential kinetics. The value of the fast initial component (τ1=0.409±0.258min) indicated that the scFv is distributed rapidly into the tissues. The mean residence time, MRT, was 45 ± 0.51 min and the clearance (CL), 114.3 ± 14.3 mL/min. From urine samples it was possible to detect significant amounts of scFv LR, which is evidence of renal elimination.
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Affiliation(s)
- Roberto Olivares-Hernández
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Unidad Cuajimalpa, Cuajimalpa de Morelos, Ciudad de México, 05348, Mexico
| | - Lidia Riaño-Umbarila
- Investigadora por México, CONAHCYT. Instituto de Biotecnología-Universidad Nacional Autónoma de México, Mexico; Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología-Universidad Nacional Autónoma de México. Avenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Baltazar Becerril
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología-Universidad Nacional Autónoma de México. Avenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Alejandro Alagón
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología-Universidad Nacional Autónoma de México. Avenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Hilda Vázquez-López
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología-Universidad Nacional Autónoma de México. Avenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos, 62210, Mexico.
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Pasdelou MP, Byelyayeva L, Malmström S, Pucheu S, Peytavy M, Laullier H, Hodges DB, Tzafriri AR, Naert G. Ototoxicity: a high risk to auditory function that needs to be monitored in drug development. Front Mol Neurosci 2024; 17:1379743. [PMID: 38756707 PMCID: PMC11096496 DOI: 10.3389/fnmol.2024.1379743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/15/2024] [Indexed: 05/18/2024] Open
Abstract
Hearing loss constitutes a major global health concern impacting approximately 1.5 billion people worldwide. Its incidence is undergoing a substantial surge with some projecting that by 2050, a quarter of the global population will experience varying degrees of hearing deficiency. Environmental factors such as aging, exposure to loud noise, and the intake of ototoxic medications are implicated in the onset of acquired hearing loss. Ototoxicity resulting in inner ear damage is a leading cause of acquired hearing loss worldwide. This could be minimized or avoided by early testing of hearing functions in the preclinical phase of drug development. While the assessment of ototoxicity is well defined for drug candidates in the hearing field - required for drugs that are administered by the otic route and expected to reach the middle or inner ear during clinical use - ototoxicity testing is not required for all other therapeutic areas. Unfortunately, this has resulted in more than 200 ototoxic marketed medications. The aim of this publication is to raise awareness of drug-induced ototoxicity and to formulate some recommendations based on available guidelines and own experience. Ototoxicity testing programs should be adapted to the type of therapy, its indication (targeting the ear or part of other medications classes being potentially ototoxic), and the number of assets to test. For multiple molecules and/or multiple doses, screening options are available: in vitro (otic cell assays), ex vivo (cochlear explant), and in vivo (in zebrafish). In assessing the ototoxicity of a candidate drug, it is good practice to compare its ototoxicity to that of a well-known control drug of a similar class. Screening assays provide a streamlined and rapid method to know whether a drug is generally safe for inner ear structures. Mammalian animal models provide a more detailed characterization of drug ototoxicity, with a possibility to localize and quantify the damage using functional, behavioral, and morphological read-outs. Complementary histological measures are routinely conducted notably to quantify hair cells loss with cochleogram. Ototoxicity studies can be performed in rodents (mice, rats), guinea pigs and large species. However, in undertaking, or at the very least attempting, all preclinical investigations within the same species, is crucial. This encompasses starting with pharmacokinetics and pharmacology efficacy studies and extending through to toxicity studies. In life read-outs include Auditory Brainstem Response (ABR) and Distortion Product OtoAcoustic Emissions (DPOAE) measurements that assess the activity and integrity of sensory cells and the auditory nerve, reflecting sensorineural hearing loss. Accurate, reproducible, and high throughput ABR measures are fundamental to the quality and success of these preclinical trials. As in humans, in vivo otoscopic evaluations are routinely carried out to observe the tympanic membrane and auditory canal. This is often done to detect signs of inflammation. The cochlea is a tonotopic structure. Hair cell responsiveness is position and frequency dependent, with hair cells located close to the cochlea apex transducing low frequencies and those at the base transducing high frequencies. The cochleogram aims to quantify hair cells all along the cochlea and consequently determine hair cell loss related to specific frequencies. This measure is then correlated with the ABR & DPOAE results. Ototoxicity assessments evaluate the impact of drug candidates on the auditory and vestibular systems, de-risk hearing loss and balance disorders, define a safe dose, and optimize therapeutic benefits. These types of studies can be initiated during early development of a therapeutic solution, with ABR and otoscopic evaluations. Depending on the mechanism of action of the compound, studies can include DPOAE and cochleogram. Later in the development, a GLP (Good Laboratory Practice) ototoxicity study may be required based on otic related route of administration, target, or known potential otic toxicity.
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Micaletti F, Escoffre JM, Kerneis S, Bouakaz A, Galvin JJ, Boullaud L, Bakhos D. Microbubble-assisted ultrasound for inner ear drug delivery. Adv Drug Deliv Rev 2024; 204:115145. [PMID: 38042259 DOI: 10.1016/j.addr.2023.115145] [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: 09/21/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023]
Abstract
Treating pathologies of the inner ear is a major challenge. To date, a wide range of procedures exists for administering therapeutic agents to the inner ear, with varying degrees of success. The key is to deliver therapeutics in a way that is minimally invasive, effective, long-lasting, and without adverse effects on vestibular and cochlear function. Microbubble-assisted ultrasound ("sonoporation") is a promising new modality that can be adapted to the inner ear. Combining ultrasound technology with microbubbles in the middle ear can increase the permeability of the round window, enabling therapeutic agents to be delivered safely and effectively to the inner ear in a targeted manner. As such, sonoporation is a promising new approach to treat hearing loss and vertigo. This review summarizes all studies on the delivery of therapeutic molecules to the inner ear using sonoporation.
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Affiliation(s)
- Fabrice Micaletti
- ENT and Cervico-Facial Surgery Department, University Hospital Center of Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
| | | | - Sandrine Kerneis
- ENT and Cervico-Facial Surgery Department, University Hospital Center of Tours, 2 Boulevard Tonnellé, 37044 Tours, France
| | - Ayache Bouakaz
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
| | - John J Galvin
- Faculty of medicine, Université de Tours, 10 boulevard Tonnellé, 37044 Tours, France; House Institute Foundation, 2100 W 3rd Street, Suite 111, Los Angeles, CA 90057, USA
| | - Luc Boullaud
- ENT and Cervico-Facial Surgery Department, University Hospital Center of Tours, 2 Boulevard Tonnellé, 37044 Tours, France
| | - David Bakhos
- ENT and Cervico-Facial Surgery Department, University Hospital Center of Tours, 2 Boulevard Tonnellé, 37044 Tours, France; UMR 1253, iBrain, Université de Tours, Inserm, Tours, France; Faculty of medicine, Université de Tours, 10 boulevard Tonnellé, 37044 Tours, France; House Institute Foundation, 2100 W 3rd Street, Suite 111, Los Angeles, CA 90057, USA
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Waring NA, Chern A, Vilarello BJ, Lang JH, Olson ES, Nakajima HH. Sheep as a Large-Animal Model for Otology Research: Temporal Bone Extraction and Transmastoid Facial Recess Surgical Approach. J Assoc Res Otolaryngol 2023; 24:487-497. [PMID: 37684421 PMCID: PMC10695901 DOI: 10.1007/s10162-023-00907-0] [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: 03/04/2023] [Accepted: 07/17/2023] [Indexed: 09/10/2023] Open
Abstract
PURPOSE Sheep are used as a large-animal model for otology research and can be used to study implantable hearing devices. However, a method for temporal bone extraction in sheep, which enables various experiments, has not been described, and literature on middle ear access is limited. We describe a method for temporal bone extraction and an extended facial recess surgical approach to the middle ear in sheep. METHODS Ten temporal bones from five Hampshire sheep head cadavers were extracted using an oscillating saw. After craniotomy and removal of the brain, a coronal cut was made at the posterior aspect of the orbit followed by a midsagittal cut of the occipital bone and disarticulation of the atlanto-occipital joint. Temporal bones were surgically prepared with an extended facial recess approach. Micro-CT scans of each temporal bone were obtained, and anatomic dimensions were measured. RESULTS Temporal bone extraction was successful in 10/10 temporal bones. Extended facial recess approach exposed the malleus, incus, stapes, and round window while preserving the facial nerve, with the following surgical considerations: minimally pneumatized mastoid; tegmen (superior limit of mastoid cavity) is low-lying and sits below temporal artery; chorda tympani sacrificed to optimize middle ear exposure; incus buttress does not obscure view of middle ear. Distance between the superior aspect of external auditory canal and tegmen was 2.7 (SD 0.9) mm. CONCLUSION We identified anatomic landmarks for temporal bone extraction and describe an extended facial recess approach in sheep that exposes the ossicles and round window. This approach is feasible for studying implantable hearing devices.
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Affiliation(s)
- Nicholas A Waring
- Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, NY, New York, USA
| | - Alexander Chern
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, NY, New York, USA
| | - Brandon J Vilarello
- Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, NY, New York, USA
| | - Jeffrey H Lang
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elizabeth S Olson
- Department of Otolaryngology-Head & Neck Surgery, NewYork-Presbyterian/Columbia University Irving Medical Center, NY, New York, USA.
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
| | - Hideko Heidi Nakajima
- Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear and Harvard Medical School, Boston, MA, USA
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Sonoporation of the Round Window Membrane on a Sheep Model: A Safety Study. Pharmaceutics 2023; 15:pharmaceutics15020442. [PMID: 36839763 PMCID: PMC9964975 DOI: 10.3390/pharmaceutics15020442] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/23/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023] Open
Abstract
Sonoporation using microbubble-assisted ultrasound increases the permeability of a biological barrier to therapeutic molecules. Application of this method to the round window membrane could improve the delivery of therapeutics to the inner ear. The aim of this study was to assess the safety of sonoporation of the round window membrane in a sheep model. To achieve this objective, we assessed auditory function and cochlear heating, and analysed the metabolomics profiles of perilymph collected after sonoporation, comparing them with those of the control ear in the same animal. Six normal-hearing ewes were studied, with one sonoporation ear and one control ear for each. A mastoidectomy was performed on both ears. On the sonoporation side, Vevo MicroMarker® microbubbles (MBs; VisualSonics-Fujifilm, Amsterdam, The Netherlands) at a concentration of 2 × 108 MB/mL were locally injected into the middle ear and exposed to 1.1 MHz sinusoidal ultrasonic waves at 0.3 MPa negative peak pressure with 40% duty cycle and 100 μs interpulse period for 1 min; this was repeated three times with 1 min between applications. The sonoporation protocol did not induce any hearing impairment or toxic overheating compared with the control condition. The metabolomic analysis did not reveal any significant metabolic difference between perilymph samples from the sonoporation and control ears. The results suggest that sonoporation of the round window membrane does not cause damage to the inner ear in a sheep model.
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Abd El-Hameed ZS, El-Shafey AAEF, Metwally MA, Abd El-Samie HAER, Kassab A. Anatomy of the rabbit inner ear using computed tomography and magnetic resonance imaging. Anat Histol Embryol 2023; 52:403-410. [PMID: 36609852 DOI: 10.1111/ahe.12899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/16/2022] [Accepted: 12/21/2022] [Indexed: 01/09/2023]
Abstract
Anatomically, the inner ear is a highly complex organ of intricate design, composed of a bony labyrinth that encases the same-shaped membranous labyrinth. It is difficult to study the three-dimensional anatomy of the inner ear because the relevant structures are very small and embedded within the petrous temporal bone, one of the densest bones in the body. The current study aimed to provide a detailed anatomic reference for the normal anatomy of the rabbit's inner ear. As a study model, ten healthy adults New Zealand White rabbit heads were used. Six heads were used for macroscopic evaluation of the bony and membranous labyrinths. The remaining four heads were evaluated radiographically, where 3D images were generated of the bony and membranous labyrinths using data sets from computed tomography (CT) and magnetic resonance imaging (MRI), respectively. The anatomical structures were identified and labelled according to NominaAnatomicaVeterinaria (NAV). Our study revealed that CT and MRI are the optimal cross-sectional imaging modalities for investigating such tiny and often inaccessible inner ear structures. As high-quality scanners are not readily available to veterinarians, the CT and MRI images generated by this research were of lower quality; therefore, high-quality dissections were used to identify/support structures seen in these images. In conclusion, this study provides one of the first investigations that uses multislice CT scans and MRI to study the rabbit's inner ear and its correlation with the corresponding anatomical images. Both anatomical, CT and MRI images will serve as a reference for interpreting pathologies relative to the rabbit's inner ear.
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Affiliation(s)
- Zeinab Said Abd El-Hameed
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Benha University, Benha, Egypt
| | | | - Mohamed Attia Metwally
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Benha University, Benha, Egypt
| | | | - A Kassab
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Benha University, Benha, Egypt
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Comparison of response properties of the electrically stimulated auditory nerve reported in human listeners and in animal models. Hear Res 2022; 426:108643. [PMID: 36343534 PMCID: PMC9986845 DOI: 10.1016/j.heares.2022.108643] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/29/2022] [Accepted: 10/20/2022] [Indexed: 11/04/2022]
Abstract
Cochlear implants (CIs) provide acoustic information to implanted patients by electrically stimulating nearby auditory nerve fibers (ANFs) which then transmit the information to higher-level neural structures for further processing and interpretation. Computational models that simulate ANF responses to CI stimuli enable the exploration of the mechanisms underlying CI performance beyond the capacity of in vivo experimentation alone. However, all ANF models developed to date utilize to some extent anatomical/morphometric data, biophysical properties and/or physiological data measured in non-human animal models. This review compares response properties of the electrically stimulated auditory nerve (AN) in human listeners and different mammalian models. Properties of AN responses to single pulse stimulation, paired-pulse stimulation, and pulse-train stimulation are presented. While some AN response properties are similar between human listeners and animal models (e.g., increased AN sensitivity to single pulse stimuli with long interphase gaps), there are some significant differences. For example, the AN of most animal models is typically more sensitive to cathodic stimulation while the AN of human listeners is generally more sensitive to anodic stimulation. Additionally, there are substantial differences in the speed of recovery from neural adaptation between animal models and human listeners. Therefore, results from animal models cannot be simply translated to human listeners. Recognizing the differences in responses of the AN to electrical stimulation between humans and other mammals is an important step for creating ANF models that are more applicable to various human CI patient populations.
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Yildiz E, Gerlitz M, Gadenstaetter AJ, Landegger LD, Nieratschker M, Schum D, Schmied M, Haase A, Kanz F, Kramer AM, Glueckert R, Staecker H, Honeder C, Arnoldner C. Single-Incision Cochlear Implantation and Hearing Evaluation in Piglets and Minipigs. Hear Res 2022; 426:108644. [DOI: 10.1016/j.heares.2022.108644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 10/20/2022] [Accepted: 10/22/2022] [Indexed: 11/04/2022]
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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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Boullaud L, Blasco H, Caillaud E, Emond P, Bakhos D. Immediate-Early Modifications to the Metabolomic Profile of the Perilymph Following an Acoustic Trauma in a Sheep Model. J Clin Med 2022; 11:jcm11164668. [PMID: 36012907 PMCID: PMC9409969 DOI: 10.3390/jcm11164668] [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: 06/23/2022] [Revised: 08/02/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
The pathophysiological mechanisms of noise-induced hearing loss remain unknown. Identifying biomarkers of noise-induced hearing loss may increase the understanding of pathophysiological mechanisms of deafness, allow for a more precise diagnosis, and inform personalized treatment. Emerging techniques such as metabolomics can help to identify these biomarkers. The objective of the present study was to investigate immediate-early changes in the perilymph metabolome following acoustic trauma. Metabolomic analysis was performed using liquid chromatography coupled to mass spectrophotometry to analyze metabolic changes in perilymph associated with noise-induced hearing loss. Sheep (n = 6) were exposed to a noise designed to induce substantial hearing loss. Perilymph was collected before and after acoustic trauma. Data were analyzed using univariate analysis and a supervised multivariate analysis based on partial least squares discriminant analysis. A metabolomic analysis showed an abundance of 213 metabolites. Four metabolites were significantly changed following acoustic trauma (Urocanate (p = 0.004, FC = 0.48), S-(5’-Adenosyl)-L-Homocysteine (p = 0.06, FC = 2.32), Trigonelline (p = 0.06, FC = 0.46) and N-Acetyl-L-Leucine (p = 0.09, FC = 2.02)). The approach allowed for the identification of new metabolites and metabolic pathways involved with acoustic trauma that were associated with auditory impairment (nerve damage, mechanical destruction, and oxidative stress). The results suggest that metabolomics provides a powerful approach to characterize inner ear metabolites which may lead to identification of new therapies and therapeutic targets.
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Affiliation(s)
- Luc Boullaud
- ENT Department and Cervico-Facial Surgery, CHU de Tours, 2 Boulevard Tonnellé, 37044 Tours, France
- INSERM U1253, iBrain, University of Tours, 10 Boulevard Tonnellé, 37000 Tours, France
- Correspondence: ; Tel.: +33-02-4747-4747
| | - Hélène Blasco
- INSERM U1253, iBrain, University of Tours, 10 Boulevard Tonnellé, 37000 Tours, France
- Department of Biochemistry and Molecular Biology, CHU de Tours, 2 Boulevard Tonnellé, 37044 Tours, France
- Faculty of Medecine, University of Tours, 10 Boulevard Tonnellé, 37000 Tours, France
| | - Eliott Caillaud
- ENT Department and Cervico-Facial Surgery, CHU de Tours, 2 Boulevard Tonnellé, 37044 Tours, France
| | - Patrick Emond
- INSERM U1253, iBrain, University of Tours, 10 Boulevard Tonnellé, 37000 Tours, France
- Faculty of Medecine, University of Tours, 10 Boulevard Tonnellé, 37000 Tours, France
| | - David Bakhos
- ENT Department and Cervico-Facial Surgery, CHU de Tours, 2 Boulevard Tonnellé, 37044 Tours, France
- INSERM U1253, iBrain, University of Tours, 10 Boulevard Tonnellé, 37000 Tours, France
- Faculty of Medecine, University of Tours, 10 Boulevard Tonnellé, 37000 Tours, France
- House Institute Foundation, Los Angeles, CA 90089, USA
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