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Gunewardene N, Lam P, Ma Y, Caruso F, Wagstaff S, Richardson RT, Wise AK. Pharmacokinetics and biodistribution of supraparticle-delivered neurotrophin 3 in the guinea pig cochlea. J Control Release 2022; 342:295-307. [PMID: 34999140 DOI: 10.1016/j.jconrel.2021.12.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 12/29/2021] [Indexed: 02/06/2023]
Abstract
Hearing loss is the most prevalent sensory disorder affecting nearly half a billion people worldwide. Aside from devices to assist hearing, such as hearing aids and cochlear implants, a drug treatment for hearing loss has yet to be developed. The neurotrophin family of growth factors has long been established as a potential therapy, however delivery of these factors into the inner ear at therapeutic levels over a sustained period of time has remained a challenge restricting clinical translation. We previously demonstrated that direct delivery of exogenous neurotrophin-3 (NT3) in the guinea pig cochleae via a bolus injection was rapidly cleared from the inner ear, with almost complete elimination 3 days post-treatment. Here, we explored the potential of suprapaticles (SPs) for NT3 delivery to the inner ear to achieve sustained delivery over time. SPs are porous spheroid structures comprised of smaller colloidal silica nanoparticles that provide a platform for long-term controlled release of therapeutics. This study aimed to assess the pharmacokinetics and biodistribution of SP-delivered NT3. We used a radioactive tracer (iodine 125: 125I) to label the NT3 to determine the loading, retention and distribution of NT3 delivered via SPs. Gamma measurements taken from 125I NT3 loaded SPs revealed high drug loading (an average of 5.3 μg of NT3 loaded per SP weighing 50 μg) and elution capacities in vitro (67% cumulative release over one month). Whole cochlear gamma measurements from SP-implanted cochleae harvested at various time points revealed detection of 125I NT3 in the guinea pig cochlea after one month, with 3.6 and 10% of the loaded drug remaining in the intracochlear and round window-implanted cochleae respectively. Autoradiography analysis of cochlear micro-sections revealed widespread 125I NT3 distribution after intracochlear SP delivery, but more restricted distribution with the round window delivery approach. Collectively, drug delivery into the inner ear using SPs support sustained, long-term availability and release of neurotrophins in the inner ear.
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Affiliation(s)
- Niliksha Gunewardene
- Bionics Institute, Melbourne, Australia; Medical Bionics Department, University of Melbourne, Australia.
| | | | - Yutian Ma
- Bionics Institute, Melbourne, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Frank Caruso
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | | | - Rachael T Richardson
- Bionics Institute, Melbourne, Australia; Medical Bionics Department, University of Melbourne, Australia; Department of Surgery (Otolaryngology), University of Melbourne, Australia
| | - Andrew K Wise
- Bionics Institute, Melbourne, Australia; Medical Bionics Department, University of Melbourne, Australia; Department of Surgery (Otolaryngology), University of Melbourne, Australia.
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2
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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.
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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
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3
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Sawamura S, Ogata G, Asai K, Razvina O, Ota T, Zhang Q, Madhurantakam S, Akiyama K, Ino D, Kanzaki S, Saiki T, Matsumoto Y, Moriyama M, Saijo Y, Horii A, Einaga Y, Hibino H. Analysis of Pharmacokinetics in the Cochlea of the Inner Ear. Front Pharmacol 2021; 12:633505. [PMID: 34012393 PMCID: PMC8128070 DOI: 10.3389/fphar.2021.633505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/16/2021] [Indexed: 11/14/2022] Open
Abstract
Hearing loss affects >5% of the global population and therefore, has a great social and clinical impact. Sensorineural hearing loss, which can be caused by different factors, such as acoustic trauma, aging, and administration of certain classes of drugs, stems primarily from a dysfunction of the cochlea in the inner ear. Few therapeutic strategies against sensorineural hearing loss are available. To develop effective treatments for this disease, it is crucial to precisely determine the behavior of ototoxic and therapeutic agents in the microenvironment of the cochlea in live animals. Since the 1980s, a number of studies have addressed this issue by different methodologies. However, there is much less information on pharmacokinetics in the cochlea than that in other organs; the delay in ontological pharmacology is likely due to technical difficulties with accessing the cochlea, a tiny organ that is encased with a bony wall and has a fine and complicated internal structure. In this review, we not only summarize the observations and insights obtained in classic and recent studies on pharmacokinetics in the cochlea but also describe relevant analytical techniques, with their strengths, limitations, and prospects.
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Affiliation(s)
- Seishiro Sawamura
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Genki Ogata
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kai Asai
- Department of Chemistry, Keio University, Yokohama, Japan
| | - Olga Razvina
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan.,G-MedEx Office, Niigata University School of Medicine, Niigata, Japan
| | - Takeru Ota
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Qi Zhang
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.,Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan.,Department of Otolaryngology, Head and Neck Surgery Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Sasya Madhurantakam
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Koei Akiyama
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan
| | - Daisuke Ino
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Sho Kanzaki
- Department of Otolaryngology, School of Medicine, Keio University, Tokyo, Japan
| | - Takuro Saiki
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yoshifumi Matsumoto
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Masato Moriyama
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yasuo Saijo
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Arata Horii
- Department of Otolaryngology, Head and Neck Surgery Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yasuaki Einaga
- Department of Chemistry, Keio University, Yokohama, Japan
| | - Hiroshi Hibino
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.,AMED-CREST, AMED, Osaka, Japan
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4
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Manrique-Huarte R, Linera-Alperi MAD, Parilli D, Rodriguez JA, Borro D, Dueck WF, Smyth D, Salt A, Manrique M. Inner ear drug delivery through a cochlear implant: Pharmacokinetics in a Macaque experimental model. Hear Res 2021; 404:108228. [PMID: 33784550 DOI: 10.1016/j.heares.2021.108228] [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: 09/22/2020] [Revised: 01/27/2021] [Accepted: 03/15/2021] [Indexed: 12/20/2022]
Abstract
OBJECTIVES The method of drug delivery directly into the cochlea with an implantable pump connected to a CI electrode array ensures long-term delivery and effective dose control, and also provides the possibility to use different drugs. The objective is to develop a model of inner ear pharmacokinetics of an implanted cochlea, with the delivery of FITC-Dextran, in the non-human primate model. DESIGN A preclinical cochlear electrode array (CI Electrode Array HL14DD, manufactured by Cochlear Ltd.) attached to an implantable peristaltic pump filled with FITC-Dextran was implanted unilaterally in a total of 15 Macaca fascicularis (Mf). Three groups were created (5 Mf in each group), according to three different drug delivery times: 2 hours, 24 hours and 7 days. Perilymph (10 samples, 1μL each) was sampled from the apex of the cochlea and measured immediately after extraction with a spectrofluorometer. After scarifying the specimens, x-Rays and histological analysis were performed. RESULTS Surgery, sampling and histological analysis were performed successfully in all specimens. FITC-Dextran quantification showed different patterns, depending on the delivery group. In the 2 hours injection experiment, an increase in FITC-Dextran concentrations over the sample collection time was seen, reaching maximum concentration peaks (420-964µM) between samples 5 and 7, decreasing in successive samples, without returning to baseline. The 24-hours and 7-days injection experiments showed even behaviour throughout the 10 samples obtained, reaching a plateau with mean concentrations ranging from 2144 to 2564 µM and from 1409 to 2502µM, respectively. Statistically significant differences between the 2 hours and 24 hours groups (p = 0.001) and between the 2 hours and 7 days groups (p = 0.037) were observed, while between the 24 hours and 7 days groups no statistical differences were found. CONCLUSIONS This experimental study shows that a model of drug delivery and pharmacokinetics using an active pump connected to an electrode array is feasible in Mf. An infusion time ranging from 2 to 24 hours is required to reach a maximum concentration peak at the apex. It establishes then an even concentration profile from base to apex that is maintained throughout the infusion time in Mf. Flow mechanisms during injection and during sampling that may explain such findings may involve cochlear aqueduct flow as well as the possible existence of substance exchange from scala tympani to extracellular spaces, such as the modiolar space or the endolymphatic sinus, acting as a substance reservoir to maintain a relatively flat concentration profile from base to apex during sampling. Leveraging the learnings achieved by experimentation in rodent models, we can move to experiment in non-human primate with the aim of achieving a useful model that provides transferrable data to human pharmacokinetics. Thus, it may broaden clinical and therapeutic approaches to inner ear diseases.
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Affiliation(s)
- R Manrique-Huarte
- Otorhinolaryngology Department, University of Navarra Clinic, Pamplona, Spain
| | | | - D Parilli
- Otorhinolaryngology Department, University of Navarra Clinic, Pamplona, Spain
| | - J A Rodriguez
- Laboratory of Atherothrombosis, Program of Cardiovascular Diseases, CIMA-Universidad de Navarra, Pamplona, Spain; IdiSNA; CIBERCV
| | - D Borro
- CEIT and Tecnun (University of Navarra), San Sebastián, Spain
| | - W F Dueck
- Cochlear Limited, 1 University Avenue, Macquarie University, NSW, 2109, Australia
| | - D Smyth
- Cochlear Limited, 1 University Avenue, Macquarie University, NSW, 2109, Australia
| | - A Salt
- Department of Otolaryngology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8115, St. Louis, MO 63110, USA
| | - M Manrique
- Otorhinolaryngology Department, University of Navarra Clinic, Pamplona, Spain
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5
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Lam P, Gunewardene N, Ma Y, Caruso F, Nguyen T, Flynn B, Wise AK, Richardson RT. A radiolabeled drug tracing method to study neurotrophin-3 retention and distribution in the cochlea after nano-based local delivery. MethodsX 2020; 7:101078. [PMID: 33072529 PMCID: PMC7549113 DOI: 10.1016/j.mex.2020.101078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 09/21/2020] [Indexed: 12/02/2022] Open
Abstract
Hearing loss is the most common sensory deficit worldwide with no approved therapeutics for treatment. Local neurotrophin delivery into the cochlea has shown great potential in protecting and repairing the sensory cells important for hearing. However, delivery of these factors into the inner ear at therapeutic levels over a sustained period of time has remained a challenge restricting clinical translation. We have developed a method to test the pharmacokinetics of neurotrophin released from porous silica particles called ‘supraparticles’ that can provide sustained release of neurotrophins to the inner ear.This report describes a radiolabeling method to examine neurotrophin retention and distribution in the cochlea. The neurotrophin was labeled with a radioactive tracer (iodine 125: 125I) and delivered into the cochlea via the supraparticle system. Gamma counts reveal drug levels and clearance in the intact cochlea, as well as accumulation in off-target organs (safety test). Autoradiography analyses using film and emulsion permit quantification and visualization of drug distribution at the cellular level. The method has a detection limit of 0.8 pg of radiolabeled neurotrophin-3 in cochlear sections exposed to film. The tracer 125I with a half-life of 59.4 days can be used to label other drugs/substances with a tyrosine residue and therefore be broadly applicable for long-term pharmacokinetic studies in other systems.
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Affiliation(s)
- Patrick Lam
- Bionics Institute, East Melbourne, Victoria 3002, Australia
- Department of Medical Bionics, University of Melbourne, Fitzroy, Victoria 3065, Australia
| | - Niliksha Gunewardene
- Bionics Institute, East Melbourne, Victoria 3002, Australia
- Department of Medical Bionics, University of Melbourne, Fitzroy, Victoria 3065, Australia
| | - Yutian Ma
- Bionics Institute, East Melbourne, Victoria 3002, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Frank Caruso
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Trung Nguyen
- Bionics Institute, East Melbourne, Victoria 3002, Australia
- Department of Medical Bionics, University of Melbourne, Fitzroy, Victoria 3065, Australia
| | - Brianna Flynn
- Bionics Institute, East Melbourne, Victoria 3002, Australia
- Department of Medical Bionics, University of Melbourne, Fitzroy, Victoria 3065, Australia
| | - Andrew K. Wise
- Bionics Institute, East Melbourne, Victoria 3002, Australia
- Department of Medical Bionics, University of Melbourne, Fitzroy, Victoria 3065, Australia
- University of Melbourne, Department of Otolaryngology, The Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia
| | - Rachael T. Richardson
- Bionics Institute, East Melbourne, Victoria 3002, Australia
- Department of Medical Bionics, University of Melbourne, Fitzroy, Victoria 3065, Australia
- University of Melbourne, Department of Otolaryngology, The Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia
- Corresponding author at: Bionics Institute, East Melbourne, Victoria 3002, Australia.
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6
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Moudgalya SS, Cahill ND, Borkholder DA. Deep Volumetric Segmentation of Murine Cochlear Compartments from Micro-Computed Tomography Images. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:1970-1975. [PMID: 33018389 PMCID: PMC7698689 DOI: 10.1109/embc44109.2020.9176596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Local drug delivery to the inner ear via micropump implants has the potential to be much more effective than oral drug delivery for treating patients with sensorineural hearing loss and to protect hearing from ototoxic insult due to noise exposure or cancer treatments. Designing micropumps to deliver appropriate concentrations of drugs to the necessary cochlear compartments is of paramount importance; however, directly measuring local drug concentrations over time throughout the cochlea is not possible. Recent approaches for indirectly quantifying local drug concentrations in animal models capture a series of magnetic resonance (MR) or micro computed tomography (µCT) images before and after infusion of a contrast agent into the cochlea. These approaches require accurately segmenting important cochlear components (scala tympani (ST), scala media (SM) and scala vestibuli (SV)) in each scan and ensuring that they are registered longitudinally across scans. In this paper, we focus on segmenting cochlear compartments from µCT volumes using V-Net, a convolutional neural network (CNN) architecture for 3-D segmentation. We show that by modifying the V-Net architecture to decrease the numbers of encoder and decoder blocks and to use dilated convolutions enables extracting local estimates of drug concentration that are comparable to those extracted using atlas-based segmentation (3.37%, 4.81%, and 19.65% average relative error in ST, SM, and SV), but in a fraction of the time. We also test the feasibility of training our network on a larger MRI dataset, and then using transfer learning to perform segmentation on a smaller number of µCT volumes, which would enable this technique to be used in the future to characterize drug delivery in the cochlea of larger mammals.
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7
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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
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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
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8
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Moudgalya SS, Wilson K, Zhu X, Budzevich MM, Walton JP, Cahill ND, Frisina RD, Borkholder DA. Cochlear pharmacokinetics - Micro-computed tomography and learning-prediction modeling for transport parameter determination. Hear Res 2019; 380:46-59. [PMID: 31181459 DOI: 10.1016/j.heares.2019.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/21/2019] [Accepted: 05/29/2019] [Indexed: 10/26/2022]
Abstract
Inner ear disorders such as sensorineural deafness and genetic diseases may one day be treated with local drug delivery to the inner ear. Current pharmacokinetic models have been based on invasive methods to measure drug concentrations, limiting them in spatial resolution, and restricting the research to larger rodents. We developed an intracochlear pharmacokinetic model based on an imaging, learning-prediction (LP) paradigm for learning transport parameters in the murine cochlea. This was achieved using noninvasive micro-computed tomography imaging of the cochlea during in vivo infusion of a contrast agent at the basal end of scala tympani through a cochleostomy. Each scan was registered in 3-D to a cochlear atlas to segment the cochlear regions with high accuracy, enabling concentrations to be extracted along the length of each scala. These spatio-temporal concentration profiles were used to learn a concentration dependent diffusion coefficient, and transport parameters between the major scalae and to clearance. The LP model results are comparable to the current state of the art model, and can simulate concentrations for cases involving different infusion molecules and different drug delivery protocols. Forward simulation results with pulsatile delivery suggest the pharmacokinetic model can be used to optimize drug delivery protocols to reduce total drug delivered and the potential for toxic side effects. While developed in the challenging murine cochlea, the processes are scalable to larger animals and different drug infusion paradigms.
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Affiliation(s)
- Sanketh S Moudgalya
- Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, Rochester, NY, USA
| | - Kevin Wilson
- Department of Electrical and Microelectronic Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, University of Southern Florida, Tampa, FL, USA; Global Center for Hearing and Speech Research, University of Southern Florida, Tampa, FL, USA
| | | | - Joseph P Walton
- Department of Medical Engineering, University of Southern Florida, Tampa, FL, USA; Global Center for Hearing and Speech Research, University of Southern Florida, Tampa, FL, USA; Department of Communication Sciences and Disorders, University of Southern Florida, Tampa, FL, USA
| | - Nathan D Cahill
- Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, Rochester, NY, USA; School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY, USA
| | - Robert D Frisina
- Department of Medical Engineering, University of Southern Florida, Tampa, FL, USA; Global Center for Hearing and Speech Research, University of Southern Florida, Tampa, FL, USA
| | - David A Borkholder
- Department of Electrical and Microelectronic Engineering, Rochester Institute of Technology, Rochester, NY, USA; Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA.
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9
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Sadreev II, Burwood GWS, Flaherty SM, Kim J, Russell IJ, Abdullin TI, Lukashkin AN. Drug Diffusion Along an Intact Mammalian Cochlea. Front Cell Neurosci 2019; 13:161. [PMID: 31080407 PMCID: PMC6497751 DOI: 10.3389/fncel.2019.00161] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/08/2019] [Indexed: 12/29/2022] Open
Abstract
Intratympanic drug administration depends on the ability of drugs to pass through the round window membrane (RW) at the base of the cochlea and diffuse from this location to the apex. While the RW permeability for many different drugs can be promoted, passive diffusion along the narrowing spiral of the cochlea is limited. Earlier measurements of the distribution of marker ions, corticosteroids, and antibiotics demonstrated that the concentration of substances applied to the RW was two to three orders of magnitude higher in the base compared to the apex. The measurements, however, involved perforating the cochlear bony wall and, in some cases, sampling perilymph. These manipulations can change the flow rate of perilymph and lead to intake of perilymph through the cochlear aqueduct, thereby disguising concentration gradients of the delivered substances. In this study, the suppressive effect of salicylate on cochlear amplification via block of the outer hair cell (OHC) somatic motility was utilized to assess salicylate diffusion along an intact guinea pig cochlea in vivo. Salicylate solution was applied to the RW and threshold elevation of auditory nerve responses was measured at different times and frequencies after application. Resultant concentrations of salicylate along the cochlea were calculated by fitting the experimental data using a mathematical model of the diffusion and clearing of salicylate in a tube of variable diameter combined with a model describing salicylate action on cochlear amplification. Concentrations reach a steady-state at different times for different cochlear locations and it takes longer to reach the steady-state at more apical locations. Even at the steady-state, the predicted concentration at the apex is negligible. Model predictions for the geometry of the longer human cochlea show even higher differences in the steady-state concentrations of the drugs between cochlear base and apex. Our findings confirm conclusions that achieving therapeutic drug concentrations throughout the entire cochlear duct is hardly possible when the drugs are applied to the RW and are distributed via passive diffusion. Assisted methods of drug delivery are needed to reach a more uniform distribution of drugs along the cochlea.
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Affiliation(s)
- Ildar I Sadreev
- Department of Medicine, Faculty of Medicine, Imperial College, London, United Kingdom
| | - George W S Burwood
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Samuel M Flaherty
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Jongrae Kim
- School of Mechanical Engineering, Institute of Design, Robotics and Optimisation, Aerospace Systems Engineering, University of Leeds, Leeds, United Kingdom
| | - Ian J Russell
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Timur I Abdullin
- Department of Biochemistry, Biotechnology and Pharmacology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Andrei N Lukashkin
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom.,Centre for Regenerative Medicine and Devices, University of Brighton, Brighton, United Kingdom
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10
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Intracochlear drug delivery: Fluorescent tracer evaluation for quantification of distribution in the cochlear partition. Eur J Pharm Sci 2019; 126:49-58. [PMID: 30195649 DOI: 10.1016/j.ejps.2018.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 08/20/2018] [Accepted: 09/06/2018] [Indexed: 11/23/2022]
Abstract
Measurement of drug distribution in the inner ear has important roles in the design of local delivery methods, such as direct, intracochlear delivery, and in assessment of emerging drug candidates in preclinical animal models. Sampling methods have been used in the past to measure drug concentrations in the cochlear fluids, but these methods provide no direct information about drug distribution in the cochlear tissues. In this work, we evaluated four fluorescent markers that simulate drug distribution in the organ of Corti after intracochlear delivery to the cochlea's scala tympani compartment. Our hypothesis is that ultimately, a cocktail comprising several fluorescent drug surrogates or fluorescently-tagged drugs, each with differing distribution, spreading, and clearance behavior, can be used to evaluate both transient and cumulative drug distributions associated with different delivery techniques. In this study, FITC-dextran, Qtracker™ 655, gentamicin Texas-Red, and FM 1-43 FX were each evaluated as candidate markers by direct intracochlear infusion into guinea-pig cochleae. Distribution of the markers was measured using fluorescence confocal microscopy imaging of cochlear whole mount dissections from animals sacrificed 3 h after the tracer-infusion. For all four tracers, strong fluorescence was observed in the tissue sections near the base, but only Qtracker™-655, gentamicin Texas-Red (GTTR) and FM 1-43 FX exhibited any specificity in labelling of the sensory hair cells. Therefore, these substances represent leading candidates for the quantification drug distribution achieved by different delivery approaches to the scala tympani.
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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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Micro-optical coherence tomography of the mammalian cochlea. Sci Rep 2016; 6:33288. [PMID: 27633610 PMCID: PMC5025881 DOI: 10.1038/srep33288] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/23/2016] [Indexed: 12/27/2022] Open
Abstract
The mammalian cochlea has historically resisted attempts at high-resolution, non-invasive imaging due to its small size, complex three-dimensional structure, and embedded location within the temporal bone. As a result, little is known about the relationship between an individual’s cochlear pathology and hearing function, and otologists must rely on physiological testing and imaging methods that offer limited resolution to obtain information about the inner ear prior to performing surgery. Micro-optical coherence tomography (μOCT) is a non-invasive, low-coherence interferometric imaging technique capable of resolving cellular-level anatomic structures. To determine whether μOCT is capable of resolving mammalian intracochlear anatomy, fixed guinea pig inner ears were imaged as whole temporal bones with cochlea in situ. Anatomical structures such as the tunnel of Corti, space of Nuel, modiolus, scalae, and cell groupings were visualized, in addition to individual cell types such as neuronal fibers, hair cells, and supporting cells. Visualization of these structures, via volumetrically-reconstructed image stacks and endoscopic perspective videos, represents an improvement over previous efforts using conventional OCT. These are the first μOCT images of mammalian cochlear anatomy, and they demonstrate μOCT’s potential utility as an imaging tool in otology research.
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Zou J, Hannula M, Misra S, Feng H, Labrador RH, Aula AS, Hyttinen J, Pyykkö I. Micro CT visualization of silver nanoparticles in the middle and inner ear of rat and transportation pathway after transtympanic injection. J Nanobiotechnology 2015; 13:5. [PMID: 25622551 PMCID: PMC4312601 DOI: 10.1186/s12951-015-0065-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/07/2015] [Indexed: 12/20/2022] Open
Abstract
Background Silver nanoparticles (Ag NPs) displayed strong activities in anti-bacterial, anti-viral, and anti-fungal studies and were reportedly efficient in treating otitis media. Information on distribution of AgNPs in different compartments of the ear is lacking. Objective To detect distribution of Ag NPs in the middle and inner ear and transportation pathways after transtympanic injection. Methods Contrast effect of Ag NPs in the micro CT imaging was assessed in a phantom. AgNPs at various concentrations (1.85 mM, 37.1 mM, and 370.7 mM) were administered to rat middle ear using transtympanic injection and cadaver heads were imaged using micro CT at several time points. Results The lowest concentration of Ag NPs that could be visualized using micro CT was 37.1 mM. No difference was observed between the solvents, deionized H2O and saline. Ag NPs at 37.1 mM were visible in the middle ear on 7 d post-administration. Ag NPs at 370.7 mM generated signals in the middle ear, ossicular chain, round window membrane, oval window, scala tympani, and Eustachian tube for both 4 h and 24 h time points. A gradient distribution of Ag NPs from the middle ear to the inner ear was detected. The pathways for Ag NPs to be transported from the middle ear into the inner ear are round and oval windows. Conclusion This study provided the imaging evidence that Ag NPs are able to access the inner ear in a dose-dependent manner after intratympanic administration, which is relevant to design the delivery concentration in the future clinic application in order to avoid adverse inner ear effect.
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Affiliation(s)
- Jing Zou
- Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Medisiinarinkatu 3, 33520, Tampere, Finland. .,Department of Otolaryngology-Head and Neck Surgery, Center for Otolaryngology-Head & Neck Surgery of Chinese PLA, Changhai Hospital, Second Military Medical University, Shanghai, China.
| | - Markus Hannula
- BioMediTech and Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland.
| | - Superb Misra
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK. .,Materials Science and Engineering, Indian Institute of Technology-Gandhinagar, Ahmedabad, India.
| | - Hao Feng
- Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Medisiinarinkatu 3, 33520, Tampere, Finland.
| | | | - Antti S Aula
- BioMediTech and Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland. .,Department of Medical Physics, Imaging Centre, Tampere University Hospital, Tampere, Finland.
| | - Jari Hyttinen
- BioMediTech and Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland.
| | - Ilmari Pyykkö
- Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Medisiinarinkatu 3, 33520, Tampere, Finland.
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Borkholder DA, Zhu X, Frisina RD. Round window membrane intracochlear drug delivery enhanced by induced advection. J Control Release 2013; 174:171-6. [PMID: 24291333 DOI: 10.1016/j.jconrel.2013.11.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 11/22/2013] [Indexed: 11/24/2022]
Abstract
Delivery of therapeutic compounds to the inner ear via absorption through the round window membrane (RWM) has advantages over direct intracochlear infusions; specifically, minimizing impact upon functional hearing measures. However, previous reports show that significant basal-to-apical concentration gradients occur, with the potential to impact treatment efficacy. Here we present a new approach to inner ear drug delivery with induced advection aiding distribution of compounds throughout the inner ear in the murine cochlea. Polyimide microtubing was placed near the RWM niche through a bullaostomy into the middle ear cavity allowing directed delivery of compounds to the RWM. We hypothesized that a posterior semicircular canalostomy would induce apical flow from the patent cochlear aqueduct to the canalostomy due to influx of cerebral spinal fluid. To test this hypothesis, young adult CBA/CaJ mice were divided into two groups: bullaostomy approach only (BA) and bullaostomy+canalostomy (B+C). Cochlear function was evaluated by distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) thresholds during and after middle ear infusion of salicylate in artificial perilymph (AP), applied near the RWM. The mice recovered for 1week, and were re-tested. The results demonstrate there was no significant impact on auditory function utilizing the RWM surgical procedure with or without the canalostomy, and DPOAE thresholds were elevated reversibly during the salicylate infusion. Comparing the threshold shifts for both methods, the B+C approach had more of a physiological effect than the BA approach, including at lower frequencies representing more apical cochlear locations. Unlike mouse cochleostomies, there was no deleterious auditory functional impact after 1week recovery from surgery. The B+C approach had more drug efficacy at lower frequencies, underscoring potential benefits for more precise control of delivery of inner ear therapeutic compounds.
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Affiliation(s)
- David A Borkholder
- Department of Electrical and Microelectronic Engineering, Rochester Institute of Technology, Rochester 14623, USA; Department of Microsystems Engineering, Rochester Institute of Technology, Rochester 14623, USA; Department of Otolaryngology, University of Rochester Medical School, Rochester 14642, USA; Department of Biomedical Engineering, University of Rochester Medical School, Rochester 14642, USA.
| | - Xiaoxia Zhu
- Department of Otolaryngology, University of Rochester Medical School, Rochester 14642, USA; International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester 14623, USA.
| | - Robert D Frisina
- Department of Otolaryngology, University of Rochester Medical School, Rochester 14642, USA; Department of Biomedical Engineering, University of Rochester Medical School, Rochester 14642, USA; Department of Neurobiology & Anatomy, University of Rochester Medical School, Rochester 14642, USA; International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester 14623, USA.
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