1
|
Robillard KN, de Vrieze E, van Wijk E, Lentz JJ. Altering gene expression using antisense oligonucleotide therapy for hearing loss. Hear Res 2022; 426:108523. [PMID: 35649738 DOI: 10.1016/j.heares.2022.108523] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/20/2022] [Accepted: 05/14/2022] [Indexed: 12/12/2022]
Abstract
Hearing loss affects more than 430 million people, worldwide, and is the third most common chronic physical condition in the United States and Europe (GBD Hearing Loss Collaborators, 2021; NIOSH, 2021; WHO, 2021). The loss of hearing significantly impacts motor and cognitive development, communication, education, employment, and overall quality of life. The inner ear houses the sensory organs for both hearing and balance and provides an accessible target for therapeutic delivery. Antisense oligonucleotides (ASOs) use various mechanisms to manipulate gene expression and can be tailor-made to treat disorders with defined genetic targets. In this review, we discuss the preclinical advancements within the field of the highly promising ASO-based therapies for hereditary hearing loss disorders. Particular focus is on ASO mechanisms of action, preclinical studies on ASO treatments of hearing loss, timing of therapeutic intervention, and delivery routes to the inner ear.
Collapse
Affiliation(s)
| | - Erik de Vrieze
- Department of Otorhinolaryngology, RUMC, Geert Grooteplein 10, Route 855, GA, Nijmegen 6525, the Netherlands; Donders Institute for Brain, Cognition, and Behavior, RUMC, Nijmegen, NL
| | - Erwin van Wijk
- Department of Otorhinolaryngology, RUMC, Geert Grooteplein 10, Route 855, GA, Nijmegen 6525, the Netherlands; Donders Institute for Brain, Cognition, and Behavior, RUMC, Nijmegen, NL.
| | - Jennifer J Lentz
- Neuroscience Center of Excellence, LSUHSC, New Orleans, LA, USA; Department of Otorhinolaryngology, LSUHSC, 2020 Gravier Street, Lions Building, Room 795, New Orleans, LA, USA.
| |
Collapse
|
2
|
Li H, Oh SH, Shin HC, Suh MW. Intratympanic Administration of Dieckol Prevents Ototoxic Hearing Loss. Mar Drugs 2022; 20:md20100622. [PMID: 36286446 PMCID: PMC9604621 DOI: 10.3390/md20100622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Systemic administration of dieckol reportedly ameliorates acute hearing loss. In this study, dieckol was delivered to the inner ear by the intratympanic route. The functional and anatomic effects and safety of dieckol were assessed using the rat ototoxicity model. MATERIALS AND METHODS Dieckol in a high-molecular-weight hyaluronic acid vehicle (dieckol+vehicle group) or vehicle without dieckol (vehicle-only group) were randomly delivered into 12 ears intratympanically. Ototoxic hearing loss was induced by intravenous administration of cisplatin, gentamicin, and furosemide. The hearing threshold and surviving outer hair cells (OHC) were enumerated. Biocompatibility was assessed by serial endoscopy of the tympanic membrane (TM), and the histology of the TM and the base of bulla (BB) mucosa was quantitatively assessed. RESULTS The hearing threshold was significantly better (difference of 20 dB SPL) in the dieckol+vehicle group than in the vehicle-only group. The number of surviving OHCs was significantly greater in the dieckol+vehicle group than in the vehicle-only group. There were no signs of inflammation or infection in the ear. The thickness of the TM and the BB mucosa did not differ between the two groups. CONCLUSION Intratympanic local delivery of dieckol may be a safe and effective method to prevent ototoxic hearing loss.
Collapse
Affiliation(s)
- Hui Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul 03080, Korea
| | - Seung Ha Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul 03080, Korea
| | - Hyeon-Cheol Shin
- Center for Molecular Intelligence, The State University of New York, Incheon 21985, Korea
| | - Myung-Whan Suh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul 03080, Korea
- Correspondence: ; Tel.: +82-2-2072-3649; Fax: +82-2-745-2387
| |
Collapse
|
3
|
Strimbu CE, Olson ES. Salicylate-induced changes in organ of Corti vibrations. Hear Res 2022; 423:108389. [PMID: 34774368 PMCID: PMC9058039 DOI: 10.1016/j.heares.2021.108389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/19/2021] [Accepted: 10/26/2021] [Indexed: 11/04/2022]
Abstract
Intra organ of Corti (OC) vibrations differ from those measured at the basilar membrane (BM), with higher amplitudes and a wide-band nonlinearity extending well below a region's best frequency. The vibrations are boosted by the cochlear amplifier, the active processes within the mammalian hearing organ, and are thus sensitive to metabolic or pharmacological manipulation. We introduced salicylate, a known blocker of outer hair cell (OHC) based electromotility, into the perilymphatic space by applying sodium salicylate onto the round window membrane. Vibration patterns of an area of the OC were mapped with phase sensitive optical coherence tomography before and after treatment; distortion product otoacoustic emissions (DPOAEs) were measured at similar times to assess the cochlear condition. Following treatment, all regions showed a loss of vibration amplitude and tuning while OHC-region vibrations retained their wide-band nonlinearity. OC vibrations, which had been relatively confined in a region including OHCs and extending to the BM at the outer pillar foot, became less confined with structures lateral to the OHCs sometimes exhibiting the highest amplitudes. Vibrations and DPOAEs could recover to baseline levels over approximately three hours post treatment. This article is part of the Special Issue Outer hair cell Edited by Joseph Santos-Sacchi and Kumar Navaratnam.
Collapse
Affiliation(s)
- C. Elliott Strimbu
- Columbia University, Department of Otolaryngology, 630 West 168th Street, New York, NY 10032, USA
| | - Elizabeth S. Olson
- Columbia University, Department of Otolaryngology, 630 West 168th Street, New York, NY 10032, USA
- Columbia University, Department of Biomedical Engineering, 1210 Amsterdam Avenue, New York, NY 10027 USA
| |
Collapse
|
4
|
Perez-Flores MC, Verschooten E, Lee JH, Kim HJ, Joris PX, Yamoah EN. Intrinsic mechanical sensitivity of mammalian auditory neurons as a contributor to sound-driven neural activity. eLife 2022; 11:74948. [PMID: 35266451 PMCID: PMC8942473 DOI: 10.7554/elife.74948] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 03/09/2022] [Indexed: 11/18/2022] Open
Abstract
Mechanosensation – by which mechanical stimuli are converted into a neuronal signal – is the basis for the sensory systems of hearing, balance, and touch. Mechanosensation is unmatched in speed and its diverse range of sensitivities, reaching its highest temporal limits with the sense of hearing; however, hair cells (HCs) and the auditory nerve (AN) serve as obligatory bottlenecks for sounds to engage the brain. Like other sensory neurons, auditory neurons use the canonical pathway for neurotransmission and millisecond-duration action potentials (APs). How the auditory system utilizes the relatively slow transmission mechanisms to achieve ultrafast speed, and high audio-frequency hearing remains an enigma. Here, we address this paradox and report that the mouse, and chinchilla, AN are mechanically sensitive, and minute mechanical displacement profoundly affects its response properties. Sound-mimicking sinusoidal mechanical and electrical current stimuli affect phase-locked responses. In a phase-dependent manner, the two stimuli can also evoke suppressive responses. We propose that mechanical sensitivity interacts with synaptic responses to shape responses in the AN, including frequency tuning and temporal phase locking. Combining neurotransmission and mechanical sensation to control spike patterns gives the mammalian AN a secondary receptor role, an emerging theme in primary neuronal functions.
Collapse
Affiliation(s)
| | - Eric Verschooten
- Laboratory of Auditory Neurophysiology, University of Leuven, Leuven, Belgium
| | | | | | - Philip X Joris
- Laboratory of Auditory Neurophysiology, University of Leuven, Leuven, Belgium
| | | |
Collapse
|
5
|
Mahdi P, Pourbakht A, Karimi Yazdi A, Rabbani Anari M, Pirhajati Mahabadi V, Kamali M. Metabotropic glutamate receptor: A new possible therapeutic target for cochlear synaptopathy. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2022; 25:75-83. [PMID: 35656439 PMCID: PMC9118270 DOI: 10.22038/ijbms.2021.59970.13296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 11/24/2021] [Indexed: 11/08/2022]
Abstract
Objectives Cochlear synaptopathy is a common cause of auditory disorders in which glutamate over-activation occurs. Modulating glutamatergic pathways has been proposed to down-regulate post-synaptic excitation. Materials and Methods 12-guinea pigs as sham and test groups were exposed to a 4-kHz noise at 104 dB SPL, for 2 hr. Pre-exposure intra-tympanic injection with LY354740 and normal saline 9% was applied in the test and sham groups. The amplitude growth of ABR-wave-I and wave-III latency shift with noise were considered in pre- and post-exposure times. The synapses were observed by transmission electron-microscopy. Results ABR thresholds recovered 1-week post-exposure in both groups. The reduction of wave-I amplitude at 4, 6, and 8 kHz were statistically different between pre- and 1- day post-exposure and recovered mostly in the sham group. The amount of latency shift in masked ABR was different between pre- and all post-exposure, and the response could not be detected at higher than 50 dB SL noise. However, the response detectability increased to 60 dB SL noise, and the significance of differences between pre- and post-exposure persisted only at the high level of noise in the test group. In electron-microscopy of sham samples, the size of the ribbon was larger, spherical with an irregularity, and hollow. The post-synaptic density was thicker and missed its flat orientation. Conclusion The higher slope of the ABR-wave I amplitude, the more tolerance of noise in masked ABR, concomitant with the histological finding that revealed less synaptic damage, confirmed the therapeutic effect of LY354740 in cochlear synaptopathy.
Collapse
Affiliation(s)
- Parvane Mahdi
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences. Tehran, Iran
| | - Akram Pourbakht
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences. Tehran, Iran,Rehabilitation Research Center, Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences. Tehran, Iran,Corresponding author: Akram Pourbakht. Rehabilitation Research Center, Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. Tel: +98-21-22250541;
| | - Alireza Karimi Yazdi
- Department of Otorhinolaryngology-Head and Neck Surgery, Imam Khomeini Educational Hospital Complex, Tehran University of Medical Sciences. Tehran, Iran
| | - Mahtab Rabbani Anari
- Otorhinolaryngology Research Center, Amir-Alam Educational Complex, Tehran University of Medical Sciences. Tehran, Iran
| | - Vahid Pirhajati Mahabadi
- Department of Neurosciences, School of Medicine. Iran University of Medical Sciences. Tehran, Iran
| | - Mohammad Kamali
- Department of Rehabilitation Management, School of Rehabilitation Sciences, Iran University of Medical Sciences. Tehran, Iran
| |
Collapse
|
6
|
Bile acid-permeation enhancement for inner ear cochlear drug - pharmacological uptake: bio-nanotechnologies in chemotherapy-induced hearing loss. Ther Deliv 2021; 12:807-819. [PMID: 34761700 DOI: 10.4155/tde-2021-0048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Ototoxicity is the damage to inner ear sensory epithelia due to exposure to certain medications and chemicals. This occurs when toxins enter the tightly controlled inner ear environment inducing hair cell death, resulting in hearing loss. Recent studies have explored hydrogel-based bio-nanotechnologies and new drug delivery formulations to prevent drug-induced hearing loss, with much attention given to administration of antioxidant drugs. Bile acids have been recognized as promising excipients due to their biocompatibility and unique physiochemical properties. As yet bile acids have not been explored in improving drug delivery to the inner ear despite improving drug stability and delivery in other systems and demonstrating positive biological effects in their own right.
Collapse
|
7
|
Flaherty SM, Russell IJ, Lukashkin AN. Drug distribution along the cochlea is strongly enhanced by low-frequency round window micro vibrations. Drug Deliv 2021; 28:1312-1320. [PMID: 34176371 PMCID: PMC8238068 DOI: 10.1080/10717544.2021.1943059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The cochlea’s inaccessibility and complex nature provide significant challenges to delivering drugs and other agents uniformly, safely and efficiently, along the entire cochlear spiral. Large drug concentration gradients are formed along the cochlea when drugs are administered to the middle ear. This undermines the major goal of attaining therapeutic drug concentration windows along the whole cochlea. Here, utilizing a well-known physiological effect of salicylate, we demonstrate a proof of concept in which drug distribution along the entire cochlea is enhanced by applying round window membrane low-frequency micro vibrations with a probe that only partially covers the round window. We provide evidence of enhanced drug influx into the cochlea and cochlear apical drug distribution without breaching cochlear boundaries. It is further suggested that ossicular functionality is not required for the effective drug distribution we report. The novel method presented here of local drug delivery to the cochlea could be implemented when ossicular functionality is absent or impeded and can be incorporated in clinically approved auditory protheses for patients who suffer with conductive, sensorineural or mixed hearing loss.
Collapse
Affiliation(s)
- Samuel M Flaherty
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK.,Centre for Regenerative Medicine and Devices, University of Brighton, Brighton, UK
| | - Ian J Russell
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Andrei N Lukashkin
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK.,Centre for Regenerative Medicine and Devices, University of Brighton, Brighton, UK
| |
Collapse
|
8
|
Shokrian M, Knox C, Kelley DH, Nam JH. Mechanically facilitated micro-fluid mixing in the organ of Corti. Sci Rep 2020; 10:14847. [PMID: 32908205 PMCID: PMC7481204 DOI: 10.1038/s41598-020-71380-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 08/06/2020] [Indexed: 12/27/2022] Open
Abstract
The cochlea is filled with two lymphatic fluids. Homeostasis of the cochlear fluids is essential for healthy hearing. The sensory epithelium called the organ of Corti separates the two fluids. Corti fluid space, extracellular fluid space within the organ of Corti, looks like a slender micro-tube. Substantial potassium ions are constantly released into the Corti fluid by sensory receptor cells. Excess potassium ions in the Corti fluid are resorbed by supporting cells to maintain fluid homeostasis. Through computational simulations, we investigated fluid mixing within the Corti fluid space. Two assumptions were made: first, there exists a longitudinal gradient of potassium ion concentration; second, outer hair cell motility causes organ of Corti deformations that alter the cross-sectional area of the Corti fluid space. We hypothesized that mechanical agitations can accelerate longitudinal mixing of Corti fluid. Corti fluid motion was determined by solving the Navier–Stokes equations incorporating nonlinear advection term. Advection–diffusion equation determined the mixing dynamics. Simulating traveling boundary waves, we found that advection and diffusion caused comparable mixing when the wave amplitude and speed were 25 nm and 7 m/s, respectively. Higher-amplitude and faster waves caused stronger advection. When physiological traveling waves corresponding to 70 dB sound pressure level at 9 kHz were simulated, advection speed was as large as 1 mm/s in the region basal to the peak responding location. Such physiological agitation accelerated longitudinal mixing by more than an order of magnitude, compared to pure diffusion. Our results suggest that fluid motion due to outer hair cell motility can help maintain longitudinal homeostasis of the Corti fluid.
Collapse
Affiliation(s)
- Mohammad Shokrian
- Department of Mechanical Engineering, University of Rochester, 203 Hopeman Engineering Bldg, Rochester, NY, 14627, USA
| | - Catherine Knox
- Department of Mechanical Engineering, University of Rochester, 203 Hopeman Engineering Bldg, Rochester, NY, 14627, USA
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester, 203 Hopeman Engineering Bldg, Rochester, NY, 14627, USA
| | - Jong-Hoon Nam
- Department of Mechanical Engineering, University of Rochester, 203 Hopeman Engineering Bldg, Rochester, NY, 14627, USA. .,Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA. .,Department of Neuroscience, University of Rochester, Rochester, NY, USA.
| |
Collapse
|
9
|
Lentz JJ, Pan B, Ponnath A, Tran CM, Nist-Lund C, Galvin A, Goldberg H, Robillard KN, Jodelka FM, Farris HE, Huang J, Chen T, Zhu H, Zhou W, Rigo F, Hastings ML, Géléoc GSG. Direct Delivery of Antisense Oligonucleotides to the Middle and Inner Ear Improves Hearing and Balance in Usher Mice. Mol Ther 2020; 28:2662-2676. [PMID: 32818431 PMCID: PMC7704764 DOI: 10.1016/j.ymthe.2020.08.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/05/2020] [Accepted: 08/02/2020] [Indexed: 12/16/2022] Open
Abstract
Usher syndrome is a syndromic form of hereditary hearing impairment that includes sensorineural hearing loss and delayed-onset retinitis pigmentosa (RP). Type 1 Usher syndrome (USH1) is characterized by congenital profound sensorineural hearing impairment and vestibular areflexia, with adolescent-onset RP. Systemic treatment with antisense oligonucleotides (ASOs) targeting the human USH1C c.216G>A splicing mutation in a knockin mouse model of USH1 restores hearing and balance. Herein, we explore the effect of delivering ASOs locally to the ear to treat hearing and vestibular dysfunction associated with Usher syndrome. Three localized delivery strategies were investigated in USH1C mice: inner ear injection, trans-tympanic membrane injection, and topical tympanic membrane application. We demonstrate, for the first time, that ASOs delivered directly to the ear correct Ush1c expression in inner ear tissue, improve cochlear hair cell transduction currents, restore vestibular afferent irregularity, spontaneous firing rate, and sensitivity to head rotation, and successfully recover hearing thresholds and balance behaviors in USH1C mice. We conclude that local delivery of ASOs to the middle and inner ear reach hair cells and can rescue both hearing and balance. These results also demonstrate the therapeutic potential of ASOs to treat hearing and balance deficits associated with Usher syndrome and other ear diseases.
Collapse
Affiliation(s)
- Jennifer J Lentz
- Department of Otorhinolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
| | - Bifeng Pan
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Abhilash Ponnath
- Department of Otorhinolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Christopher M Tran
- Department of Otorhinolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Carl Nist-Lund
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alice Galvin
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hannah Goldberg
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Katelyn N Robillard
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Francine M Jodelka
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Hamilton E Farris
- Department of Otorhinolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Jun Huang
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Tianwen Chen
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Hong Zhu
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Wu Zhou
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Inc., Carlsbad, CA 92008, USA
| | - Michelle L Hastings
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Gwenaëlle S G Géléoc
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
10
|
Prenzler NK, Salcher R, Lenarz T, Gaertner L, Warnecke A. Dose-Dependent Transient Decrease of Impedances by Deep Intracochlear Injection of Triamcinolone With a Cochlear Catheter Prior to Cochlear Implantation-1 Year Data. Front Neurol 2020; 11:258. [PMID: 32390924 PMCID: PMC7194199 DOI: 10.3389/fneur.2020.00258] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 03/20/2020] [Indexed: 02/02/2023] Open
Abstract
Administration of low-dose steroids via a catheter inserted into the cochlea to apply pharmaceuticals to more apical regions was previously shown not to be sufficient for long-term reduction of electrode impedances. The aim of the present study was to investigate the effect of intra-cochlear high-dose triamcinolone application on impedances in cochlear implant recipients. Patients received low-dose (4 mg/ml; n = 5) or high-dose (20 mg/ml; n = 5) triamcinolone via a cochlear catheter just prior to the insertion of a Med-El Flex28 electrode. Impedances were measured at defined time points from intra-operatively up to 12 months after first fitting and retrospectively compared with a control group (no steroid application). Patients who received a high-dose application of crystalloid triamcinolone showed significantly reduced impedances in the first fitting measurements compared to the control group. This effect was no longer detectable in patients of the low-dose group at that time. Looking at the different regions of the electrode, the impedance values were lowered significantly only at the basal and medial contacts. At later time points, there were no significant differences between any of the groups. This is the first study to demonstrate a dose-dependent reduction of impedances by deep intra-cochlear injection of triamcinolone in cochlear implant patients. With a high-dose, single application of triamcinolone using a cochlear catheter prior to insertion of a Flex28 electrode, the impedances can be significantly reduced up to and including the first fitting. Although the effect was longer lasting than when compared to low-dose triamcinolone, it was also not permanent.
Collapse
Affiliation(s)
- Nils K Prenzler
- Department of Otorhinolaryngology, Head and Neck Surgery, Hanover Medical School, Hanover, Germany.,Cluster of Excellence "Hearing4all2.0" of the German Research Foundation, Hanover, Germany
| | - Rolf Salcher
- Department of Otorhinolaryngology, Head and Neck Surgery, Hanover Medical School, Hanover, Germany.,Cluster of Excellence "Hearing4all2.0" of the German Research Foundation, Hanover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hanover Medical School, Hanover, Germany.,Cluster of Excellence "Hearing4all2.0" of the German Research Foundation, Hanover, Germany
| | - Lutz Gaertner
- Department of Otorhinolaryngology, Head and Neck Surgery, Hanover Medical School, Hanover, Germany.,Cluster of Excellence "Hearing4all2.0" of the German Research Foundation, Hanover, Germany
| | - Athanasia Warnecke
- Department of Otorhinolaryngology, Head and Neck Surgery, Hanover Medical School, Hanover, Germany.,Cluster of Excellence "Hearing4all2.0" of the German Research Foundation, Hanover, Germany
| |
Collapse
|
11
|
Lukashkin AN, Sadreev II, Zakharova N, Russell IJ, Yarin YM. Local Drug Delivery to the Entire Cochlea without Breaching Its Boundaries. iScience 2020; 23:100945. [PMID: 32151971 PMCID: PMC7063177 DOI: 10.1016/j.isci.2020.100945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/11/2020] [Accepted: 02/21/2020] [Indexed: 12/12/2022] Open
Abstract
The mammalian cochlea is one of the least accessible organs for drug delivery. Systemic administration of many drugs is severely limited by the blood-labyrinth barrier. Local intratympanic administration into the middle ear would be a preferable option in this case, and the only option for many newly emerging classes of drugs, but it leads to the formation of drug concentration gradients along the extensive, narrow cochlea. The gradients are orders of magnitude and well outside the therapeutic windows. Here we present an efficient, quick, and simple method of cochlear pumping, through large-amplitude, low-frequency reciprocal oscillations of the stapes and round window, which can consistently and uniformly deliver drugs along the entire length of the intact cochlea within minutes without disrupting the cochlear boundaries. The method should facilitate novel ways of approaching the treatment of inner ear disorders because it overcomes the challenge of delivering therapeutics along the entire cochlear length. Systemic delivery of drugs to the inner ear is limited by the blood-labyrinth barrier Middle ear administration results in pronounced drug gradients along the cochlea Cochlear pumping distributes drugs evenly along the entire cochlea within minutes
Collapse
Affiliation(s)
- Andrei N Lukashkin
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK; Centre for Regenerative Medicine and Devices, University of Brighton, Brighton BN2 4GJ, UK.
| | - Ildar I Sadreev
- Faculty of Medicine, Department of Medicine, Imperial College, London SW7 2AZ, UK
| | | | - Ian J Russell
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK
| | | |
Collapse
|