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Wang X, Zhou Z, Yu C, He K, Sun L, Kou Y, Zhang M, Zhang Z, Luo P, Wen L, Chen G. A prestin-targeting peptide-guided drug delivery system rearranging concentration gradient in the inner ear: An improved strategy against hearing loss. Eur J Pharm Sci 2023; 187:106490. [PMID: 37295658 DOI: 10.1016/j.ejps.2023.106490] [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: 03/30/2023] [Revised: 05/23/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023]
Abstract
Hearing loss is mainly due to outer hair cell (OHC) damage in three cochlear turns. Local administration via the round window membrane (RWM) has considerable otological clinical potential in bypassing the blood-labyrinth barrier. However, insufficient drug distribution in the apical and middle cochlear turns results in unsatisfactory efficacy. We functionalized poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) with targeting peptide A665, which specifically bound to prestin, a protein uniquely expressed in OHCs. The modification facilitated the cellular uptake and RWM permeability of NPs. Notably, the guide of A665 towards OHCs enabled more NPs perfusion in the apical and middle cochlear turns without decreasing accumulation in the basal cochlear turn. Subsequently, curcumin (CUR), an appealing anti-ototoxic drug, was encapsulated in NPs. In aminoglycoside-treated guinea pigs with the worst hearing level, CUR/A665-PLGA NPs, with superior performance to CUR/PLGA NPs, almost completely preserved the OHCs in three cochlear turns. The lack of increased low-frequencies hearing thresholds further confirmed that the delivery system with prestin affinity mediated cochlear distribution rearrangement. Good inner ear biocompatibility and little or no embryonic zebrafish toxicity were observed throughout the treatment. Overall, A665-PLGA NPs act as desirable tools with sufficient inner ear delivery for improved efficacy against severe hearing loss.
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Affiliation(s)
- Xinrui Wang
- Guangdong Provincial Key Laboratory of Advanced Drug Delivery & Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System & Class III Laboratory of Modern Chinese Medicine Preparation & Key Laboratory of Modern Chinese Medicine of Education Department of Guangdong Province, Center for Drug Research and Development, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Zeming Zhou
- Guangdong Provincial Key Laboratory of Advanced Drug Delivery & Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System & Class III Laboratory of Modern Chinese Medicine Preparation & Key Laboratory of Modern Chinese Medicine of Education Department of Guangdong Province, Center for Drug Research and Development, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Chong Yu
- Guangdong Provincial Key Laboratory of Advanced Drug Delivery & Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System & Class III Laboratory of Modern Chinese Medicine Preparation & Key Laboratory of Modern Chinese Medicine of Education Department of Guangdong Province, Center for Drug Research and Development, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Kerui He
- Guangdong Provincial Key Laboratory of Advanced Drug Delivery & Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System & Class III Laboratory of Modern Chinese Medicine Preparation & Key Laboratory of Modern Chinese Medicine of Education Department of Guangdong Province, Center for Drug Research and Development, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Lifang Sun
- Guangdong Provincial Key Laboratory of Advanced Drug Delivery & Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System & Class III Laboratory of Modern Chinese Medicine Preparation & Key Laboratory of Modern Chinese Medicine of Education Department of Guangdong Province, Center for Drug Research and Development, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Yuwei Kou
- Guangdong Provincial Key Laboratory of Advanced Drug Delivery & Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System & Class III Laboratory of Modern Chinese Medicine Preparation & Key Laboratory of Modern Chinese Medicine of Education Department of Guangdong Province, Center for Drug Research and Development, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Ming Zhang
- Guangdong Sunho Pharmaceutical Co. Ltd, Zhongshan 528437, China
| | - Zhifeng Zhang
- State Key Laboratory for Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau 000853, China
| | - Pei Luo
- State Key Laboratory for Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau 000853, China
| | - Lu Wen
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China.
| | - Gang Chen
- Guangdong Provincial Key Laboratory of Advanced Drug Delivery & Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System & Class III Laboratory of Modern Chinese Medicine Preparation & Key Laboratory of Modern Chinese Medicine of Education Department of Guangdong Province, Center for Drug Research and Development, Guangdong Pharmaceutical University, Guangzhou 510006, China.
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2
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Goyal MM, Zhou NJ, Vincent PFY, Hoffman ES, Goel S, Wang C, Sun DQ. Rationally Designed Magnetic Nanoparticles for Cochlear Drug Delivery: Synthesis, Characterization, and In Vitro Biocompatibility in a Murine Model. OTOLOGY & NEUROTOLOGY OPEN 2022; 2:e013. [PMID: 38516629 PMCID: PMC10950169 DOI: 10.1097/ono.0000000000000013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 06/03/2022] [Indexed: 03/23/2024]
Abstract
Hypothesis Magnetic nanoparticles (MNPs) for cochlear drug delivery can be precisely engineered for biocompatibility in the cochlea. Background MNPs are promising drug delivery vehicles that can enhance the penetration of both small and macromolecular therapeutics into the cochlea. However, concerns exist regarding the application of oxidative, metal-based nanomaterials to delicate sensory tissues of the inner ear. Translational development of MNPs for cochlear drug deliver requires specifically tuned nanoparticles that are not cytotoxic to inner ear tissues. We describe the synthesis and characterization of precisely tuned MNP vehicles, and their in vitro biocompatibility in murine organ of Corti organotypic cultures. Methods MNPs were synthesized via 2-phase ligand transfer process with precise control of nanoparticle size. Core and hydrodynamic sizes of nanoparticles were characterized using electron microscopy and dynamic light scattering, respectively. In vitro biocompatibility was assayed via mouse organ of Corti organotypic cultures with and without an external magnetic field gradient. Imaging was performed using immunohistochemical labeling and confocal microscopy. Outer hair cell, inner hair cell, and spiral ganglion neurites were individually quantified. Results Monocore PEG-MNPs of 45 and 148 nm (mean hydrodynamic diameter) were synthesized. Organ of Corti cultures demonstrated preserved outer hair cell, inner hair cell, and neurite counts across 2 MNP sizes and doses, and irrespective of external magnetic field gradient. Conclusion MNPs can be custom-synthesized with precise coating, size, and charge properties specific for cochlear drug delivery while also demonstrating biocompatibility in vitro.
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Affiliation(s)
- Mukund M. Goyal
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Nancy J. Zhou
- School of Medicine, Johns Hopkins University, Baltimore, MD
| | - Philippe F. Y. Vincent
- Department of Otolaryngology – Head and Neck Surgery, Johns Hopkins University, Baltimore, MD
| | - Elina S. Hoffman
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Shiv Goel
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Chao Wang
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Daniel Q. Sun
- Department of Otolaryngology – Head and Neck Surgery, Johns Hopkins University, Baltimore, MD
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Jeong SH, Kim Y, Lyu AR, Shin SA, Kim TH, Huh YH, Je AR, Gajibhiye A, Yu Y, Jin Y, Park MJ, Park YH. Junctional Modulation of Round Window Membrane Enhances Dexamethasone Uptake into the Inner Ear and Recovery after NIHL. Int J Mol Sci 2021; 22:ijms221810061. [PMID: 34576224 PMCID: PMC8464844 DOI: 10.3390/ijms221810061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 11/16/2022] Open
Abstract
Delivery of substances into the inner ear via local routes is increasingly being used in clinical treatment. Studies have focused on methods to increase permeability through the round window membrane (RWM) and enhance drug diffusion into the inner ear. However, the clinical applications of those methods have been unclear and few studies have investigated the efficacy of methods in an inner ear injury model. Here, we employed the medium chain fatty acid caprate, a biologically safe, clinically applicable substance, to modulate tight junctions of the RWM. Intratympanic treatment of sodium caprate (SC) induced transient, but wider, gaps in intercellular spaces of the RWM epithelial layer and enhanced the perilymph and cochlear concentrations/uptake of dexamethasone. Importantly, dexamethasone co-administered with SC led to significantly more rapid recovery from noise-induced hearing loss at 4 and 8 kHz, compared with the dexamethasone-only group. Taken together, our data indicate that junctional modulation of the RWM by SC enhances dexamethasone uptake into the inner ear, thereby hastening the recovery of hearing sensitivity after noise trauma.
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Affiliation(s)
- Seong-Hun Jeong
- Department of Medical Science, Chungnam National University, Daejeon 35015, Korea; (S.-H.J.); (A.-R.L.); (A.G.)
| | - Yoonjoong Kim
- Department of Otolaryngology—Head and Neck Surgery, Chungbuk National University Hospital, Cheongju 28644, Korea;
| | - Ah-Ra Lyu
- Department of Medical Science, Chungnam National University, Daejeon 35015, Korea; (S.-H.J.); (A.-R.L.); (A.G.)
- Department of Otolaryngology—Head and Neck Surgery, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (Y.Y.)
| | - Sun-Ae Shin
- Department of Otolaryngology—Head and Neck Surgery, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (Y.Y.)
- Brain Research Institute, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Tae Hwan Kim
- Biomedical Research Institute, Chungnam National University Hospital, Daejeon 35015, Korea;
| | - Yang Hoon Huh
- Electron Microscopy Research Center, Korea Basic Science Institute, Cheongju 28116, Korea; (Y.H.H.); (A.R.J.)
| | - A Reum Je
- Electron Microscopy Research Center, Korea Basic Science Institute, Cheongju 28116, Korea; (Y.H.H.); (A.R.J.)
| | - Akanksha Gajibhiye
- Department of Medical Science, Chungnam National University, Daejeon 35015, Korea; (S.-H.J.); (A.-R.L.); (A.G.)
| | - Yang Yu
- Department of Otolaryngology—Head and Neck Surgery, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (Y.Y.)
| | - Yongde Jin
- Department of Otolaryngology—Head and Neck Surgery, Yanbian University Hospital, Yanji 133000, China;
| | - Min Jung Park
- Department of Otolaryngology—Head and Neck Surgery, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (Y.Y.)
- Brain Research Institute, College of Medicine, Chungnam National University, Daejeon 35015, Korea
- Correspondence: (M.J.P.); (Y.-H.P.)
| | - Yong-Ho Park
- Department of Medical Science, Chungnam National University, Daejeon 35015, Korea; (S.-H.J.); (A.-R.L.); (A.G.)
- Department of Otolaryngology—Head and Neck Surgery, Chungnam National University, Daejeon 35015, Korea; (S.-A.S.); (Y.Y.)
- Brain Research Institute, College of Medicine, Chungnam National University, Daejeon 35015, Korea
- Biomedical Research Institute, Chungnam National University Hospital, Daejeon 35015, Korea;
- Correspondence: (M.J.P.); (Y.-H.P.)
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Abstract
PURPOSE OF REVIEW Treatment of auditory dysfunction is dependent on inner ear drug delivery, with microtechnologies playing an increasingly important role in cochlear access and pharmacokinetic profile control. This review examines recent developments in the field for clinical and animal research environments. RECENT FINDINGS Micropump technologies are being developed for dynamic control of flow rates with refillable reservoirs enabling timed delivery of multiple agents for protection or regeneration therapies. These micropumps can be combined with cochlear implants with integral catheters or used independently with cochleostomy or round window membrane (RWM) delivery modalities for therapy development in animal models. Sustained release of steroids with coated cochlear implants remains an active research area with first-time-in-human demonstration of reduced electrode impedances. Advanced coatings containing neurotrophin producing cells have enhanced spiral ganglion neuron survival in animal models, and have proven safe in a human study. Microneedles have emerged for controlled microperforation of the RWM for significant enhancement in permeability, combinable with emerging matrix formulations that optimize biological interaction and drug release kinetics. SUMMARY Microsystem technologies are providing enhanced and more controlled access to the inner ear for advanced drug delivery approaches, alone and in conjunction with cochlear implants.
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Raghu V, Ramakrishna Y, Burkard RF, Sadeghi SG. A novel intracochlear injection method for rapid drug delivery to vestibular end organs. J Neurosci Methods 2020; 341:108689. [PMID: 32380226 DOI: 10.1016/j.jneumeth.2020.108689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 03/15/2020] [Accepted: 03/15/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND Injection into the inner ear through the round window (RW) or a cochleostomy is a reliable method for delivering drugs or viruses to the cochlea. This method has been less effective for fast deliveries to vestibular end organs. NEW METHOD We describe a novel approach for rapid delivery of drugs to the vestibular end organ via the oval window (OW) and scala vestibuli in 1-3 month old C57BL/6 mice. The OW was directly accessed through the external ear canal after ablating the tympanic membrane and middle ear ossicles. A canalostomy in the superior canal provided a low pressure point for faster transit of injected solution from the OW to the vestibular neuroepithelia, allowing for higher rates of injection. RESULTS The efficacy of this technique was shown by fast transit times of a colored artificial perilymph from the OW to the utricle and the ampullae of the horizontal and superior canals in ∼2 min. Following injection, the response of the vestibular nerve was preserved, as measured by the vestibular sensory evoked potentials (VsEP). COMPARISON WITH EXISTING METHODS Previous studies have used posterior semicircular canals or the RW with canalostomy to gain access to vestibular end organs in mice. The OW with canalostomy, provides the means for high injection rates and fast and reliable delivery of drugs to vestibular hair cells and afferent terminals. CONCLUSIONS The presented method for injections through the OW provides rapid delivery of solutions to vestibular end organs without adversely affecting vestibular nerve responses measured by VsEP.
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Affiliation(s)
- Vishal Raghu
- Center for Hearing and Deafness, Dept. of Communicative Disorders and Sciences, State University of New York at Buffalo, Buffalo, NY, United States; Neuroscience Program, State University of New York at Buffalo, Buffalo, NY, United States
| | - Yugandhar Ramakrishna
- Center for Hearing and Deafness, Dept. of Communicative Disorders and Sciences, State University of New York at Buffalo, Buffalo, NY, United States; Dept. of Communication Disorders and Sciences, California State University - Northridge, Northridge, CA, United States
| | - Robert F Burkard
- Dept. of Rehabilitation Sciences, State University of New York at Buffalo, Buffalo, NY, United States
| | - Soroush G Sadeghi
- Center for Hearing and Deafness, Dept. of Communicative Disorders and Sciences, State University of New York at Buffalo, Buffalo, NY, United States; Neuroscience Program, State University of New York at Buffalo, Buffalo, NY, United States.
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6
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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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7
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Patel J, Szczupak M, Rajguru S, Balaban C, Hoffer ME. Inner Ear Therapeutics: An Overview of Middle Ear Delivery. Front Cell Neurosci 2019; 13:261. [PMID: 31244616 PMCID: PMC6580187 DOI: 10.3389/fncel.2019.00261] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/24/2019] [Indexed: 12/12/2022] Open
Abstract
There are a variety of methods to access the inner ear and many of these methods depend on utilizing the middle ear as a portal. In this approach the middle ear can be used as a passive receptacle, as part of an active drug delivery system, or simply as the most convenient way to access the inner ear directly in human subjects. The purpose of this volume is to examine some of the more cutting-edge approaches to treating the middle ear. Before considering these therapies, this manuscript provides an overview of some therapies that have been delivered through the middle ear both in the past and at the current time. This manuscript also serves as a review of many of the methods for accessing the inner ear that directly utilize or pass though the middle ear. This manuscript provides the reader a basis for understanding middle ear delivery, the basis of delivery of medicines via cochlear implants, and examines the novel approach of using hypothermia as a method of altering the responses of the inner ear to damage.
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Affiliation(s)
- Jaimin Patel
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Mikhaylo Szczupak
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Suhrud Rajguru
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Carey Balaban
- Department of Otolaryngology and Biomedical Engineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Michael E. Hoffer
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
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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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Forouzandeh F, Zhu X, Alfadhel A, Ding B, Walton JP, Cormier D, Frisina RD, Borkholder DA. A nanoliter resolution implantable micropump for murine inner ear drug delivery. J Control Release 2019; 298:27-37. [PMID: 30690105 DOI: 10.1016/j.jconrel.2019.01.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/19/2018] [Accepted: 01/24/2019] [Indexed: 10/27/2022]
Abstract
Advances in protective and restorative biotherapies have created new opportunities to use site-directed, programmable drug delivery systems to treat auditory and vestibular disorders. Successful therapy development that leverages the transgenic, knock-in, and knock-out variants of mouse models of human disease requires advanced microsystems specifically designed to function with nanoliter precision and with system volumes suitable for implantation. Here we present results for a novel biocompatible, implantable, scalable, and wirelessly controlled peristaltic micropump. The micropump configuration included commercially available catheter microtubing (250 μm OD, 125 μm ID) that provided a biocompatible leak-free flow path while avoiding complicated microfluidic interconnects. Peristaltic pumping was achieved by sequentially compressing the microtubing via expansion and contraction of a thermal phase-change material located in three chambers integrated adjacent to the microtubing. Direct-write micro-scale printing technology was used to build the mechanical components of the micropump around the microtubing directly on the back of a printed circuit board assembly (PCBA). The custom PCBA was fabricated using standard commercial processes providing microprocessor control of actuation and Bluetooth wireless communication through an Android application. The results of in vitro characterization indicated that nanoliter resolution control over the desired flow rates of 10-100 nL/min was obtained by changing the actuation frequency. Applying 10× greater than physiological backpressures and ± 3 °C ambient temperature variation did not significantly affect flow rates. Three different micropumps were tested on six mice for in vivo implantation of the catheter microtubing into the round window membrane niche for infusion of a known ototoxic compound (sodium salicylate) at 50 nL/min for 20 min. Real-time shifts in distortion product otoacoustic emission thresholds and amplitudes were measured during the infusion. There were systematic increases in distortion product threshold shifts during the 20-min perfusions; the mean shift was 15 dB for the most basal region. A biocompatibility study was performed to evaluate material suitability for chronic subcutaneous implantation and clinical translational development. The results indicated that the micropump components successfully passed key biocompatibility tests. A micropump prototype was implanted for one month without development of inflammation or infection. Although tested here on the small murine cochlea, this low-cost design and fabrication methodology is scalable for use in larger animals and for clinical applications in children and adults by appropriate scaling of the microtubing diameter and actuator volume.
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Affiliation(s)
- Farzad Forouzandeh
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Xiaoxia Zhu
- Department of Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Ahmed Alfadhel
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Bo Ding
- Department of Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Joseph P Walton
- Department of Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Department of Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Department of Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Denis Cormier
- Department of Industrial and Systems Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Robert D Frisina
- Department of Chemical & Biomedical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Department of Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA; Department of Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - David A Borkholder
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA.
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11
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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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Abstract
Sensorineural hearing impairment is the most common sensory disorder and a major health and socio-economic issue in industrialized countries. It is primarily due to the degeneration of mechanosensory hair cells and spiral ganglion neurons in the cochlea via complex pathophysiological mechanisms. These occur following acute and/or chronic exposure to harmful extrinsic (e.g., ototoxic drugs, noise...) and intrinsic (e.g., aging, genetic) causative factors. No clinical therapies currently exist to rescue the dying sensorineural cells or regenerate these cells once lost. Recent studies have, however, provided renewed hope, with insights into the therapeutic targets allowing the prevention and treatment of ototoxic drug- and noise-induced, age-related hearing loss as well as cochlear cell degeneration. Moreover, genetic routes involving the replacement or corrective editing of mutant sequences or defected genes are showing promise, as are cell-replacement therapies to repair damaged cells for the future restoration of hearing in deaf people. This review begins by recapitulating our current understanding of the molecular pathways that underlie cochlear sensorineural damage, as well as the survival signaling pathways that can provide endogenous protection and tissue rescue. It then guides the reader through to the recent discoveries in pharmacological, gene and cell therapy research towards hearing protection and restoration as well as their potential clinical application.
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Affiliation(s)
- Jing Wang
- INSERM UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; and University of Montpellier, Montpellier, France
| | - Jean-Luc Puel
- INSERM UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; and University of Montpellier, Montpellier, France
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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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Peppi M, Marie A, Belline C, Borenstein JT. Intracochlear drug delivery systems: a novel approach whose time has come. Expert Opin Drug Deliv 2018; 15:319-324. [PMID: 29480039 DOI: 10.1080/17425247.2018.1444026] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- M Peppi
- a Biomedical Engineering Center , Draper , Cambridge , MA , USA
| | - A Marie
- b CILcare, Montpellier, FR/Cambridge , Cambridge , MA , USA
| | - C Belline
- b CILcare, Montpellier, FR/Cambridge , Cambridge , MA , USA
| | - J T Borenstein
- a Biomedical Engineering Center , Draper , Cambridge , MA , USA
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Enhanced viral-mediated cochlear gene delivery in adult mice by combining canal fenestration with round window membrane inoculation. Sci Rep 2018; 8:2980. [PMID: 29445157 PMCID: PMC5812997 DOI: 10.1038/s41598-018-21233-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/31/2018] [Indexed: 12/22/2022] Open
Abstract
Cochlear gene therapy holds promise for the treatment of genetic deafness. Assessing its impact in adult murine models of hearing loss, however, has been hampered by technical challenges that have made it difficult to establish a robust method to deliver transgenes to the mature murine inner ear. Here in we demonstrate the feasibility of a combined round window membrane injection and semi-circular canal fenestration technique in the adult cochlea. Injection of both AAV2/9 and AAV2/Anc80L65 via this approach in P15–16 and P56–60 mice permits robust eGFP transduction of virtually all inner hair cells throughout the cochlea with variable transduction of vestibular hair cells. Auditory thresholds are not compromised. Transduction rate and cell tropism is primarily influenced by viral titer and AAV serotype but not age at injection. This approach is safe, versatile and efficient. Its use will facilitate studies using cochlear gene therapy in murine models of hearing loss over a wide range of time points.
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Frisina RD, Ding B, Zhu X, Walton JP. Age-related hearing loss: prevention of threshold declines, cell loss and apoptosis in spiral ganglion neurons. Aging (Albany NY) 2017; 8:2081-2099. [PMID: 27667674 PMCID: PMC5076453 DOI: 10.18632/aging.101045] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/08/2016] [Indexed: 12/18/2022]
Abstract
Age-related hearing loss (ARHL) -presbycusis - is the most prevalent neurodegenerative disease and number one communication disorder of our aged population; and affects hundreds of millions of people worldwide. Its prevalence is close to that of cardiovascular disease and arthritis, and can be a precursor to dementia. The auditory perceptual dysfunction is well understood, but knowledge of the biological bases of ARHL is still somewhat lacking. Surprisingly, there are no FDA-approved drugs for treatment. Based on our previous studies of human subjects, where we discovered relations between serum aldosterone levels and the severity of ARHL, we treated middle age mice with aldosterone, which normally declines with age in all mammals. We found that hearing thresholds and suprathreshold responses significantly improved in the aldosterone-treated mice compared to the non-treatment group. In terms of cellular and molecular mechanisms underlying this therapeutic effect, additional experiments revealed that spiral ganglion cell survival was significantly improved, mineralocorticoid receptors were upregulated via post-translational protein modifications, and age-related intrinsic and extrinsic apoptotic pathways were blocked by the aldosterone therapy. Taken together, these novel findings pave the way for translational drug development towards the first medication to prevent the progression of ARHL.
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Affiliation(s)
- Robert D Frisina
- Department Communication Sciences and Disorders, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA.,Department Chemical and Biomedical Engineering, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA
| | - Bo Ding
- Department Communication Sciences and Disorders, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA
| | - Xiaoxia Zhu
- Department Chemical and Biomedical Engineering, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA
| | - Joseph P Walton
- Department Communication Sciences and Disorders, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA.,Department Chemical and Biomedical Engineering, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA
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Johnson DG, Borkholder DA. Towards an Implantable, Low Flow Micropump That Uses No Power in the Blocked-Flow State. MICROMACHINES 2016; 7:E99. [PMID: 30404274 PMCID: PMC6189832 DOI: 10.3390/mi7060099] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/26/2016] [Accepted: 05/20/2016] [Indexed: 11/25/2022]
Abstract
Low flow rate micropumps play an increasingly important role in drug therapy research. Infusions to small biological structures and lab-on-a-chip applications require ultra-low flow rates and will benefit from the ability to expend no power in the blocked-flow state. Here we present a planar micropump based on gallium phase-change actuation that leverages expansion during solidification to occlude the flow channel in the off-power state. The presented four chamber peristaltic micropump was fabricated with a combination of Micro Electro Mechanical System (MEMS) techniques and additive manufacturing direct write technologies. The device is 7 mm × 13 mm × 1 mm (<100 mm³) with the flow channel and exterior coated with biocompatible Parylene-C, critical for implantable applications. Controllable pump rates from 18 to 104 nL/min were demonstrated, with 11.1 ± 0.35 nL pumped per actuation at an efficiency of 11 mJ/nL. The normally-closed state of the gallium actuator prevents flow and diffusion between the pump and the biological system or lab-on-a-chip, without consuming power. This is especially important for implanted applications with periodic drug delivery regimens.
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Affiliation(s)
- Dean G Johnson
- Rochester Institute of Technology, Microsystems Engineering, Rochester, NY 14623, USA.
| | - David A Borkholder
- Rochester Institute of Technology, Microsystems Engineering, Rochester, NY 14623, USA.
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Frisina RD, Frisina DR. Physiological and neurobiological bases of age-related hearing loss: biotherapeutic implications. Am J Audiol 2015; 22:299-302. [PMID: 24018570 DOI: 10.1044/1059-0889(2013/13-0003)] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
PURPOSE The aim of this study was to highlight growing evidence of interactions between hormones and the structure and function of the auditory system. METHOD Recent studies implicating sex hormones and other natural hormones in the modulation of hearing status in age-related hearing loss were reviewed. RESULTS Progesterone, a sex hormone, has been shown to have negative effects on the hearing of older women and aging mice, whereas, in contrast, estrogen was found in some cases to have a positive influence. Aldosterone, used in studies of animal models of autoimmune hearing loss, slowed the progression of hearing loss. Follow-up studies in humans revealed that auditory measures varied as serum aldosterone levels shifted within the normal range, in otherwise healthy older subjects. This was true for simple as well as complex auditory tasks (i.e., sound spatial processing), suggesting benefits of aldosterone to postperipheral auditory processing as well. In addition, evidence suggests that this functional hearing improvement occurred in association with anatomical improvements to the stria vascularis--an important site of anatomical change in presbycusis. CONCLUSIONS Audiology is now at the point where the search for biomedical interventions to modulate or prevent age-related hearing loss can move forward. Such interventions would require multidisciplinary collaborative initiatives by researchers in such areas as drug development, anatomy, auditory physiological and perceptual testing, and drug microdelivery systems.
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Ayoob AM, Borenstein JT. The role of intracochlear drug delivery devices in the management of inner ear disease. Expert Opin Drug Deliv 2014; 12:465-79. [PMID: 25347140 DOI: 10.1517/17425247.2015.974548] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
INTRODUCTION Diseases of the inner ear include those of the auditory and vestibular systems, and frequently result in disabling hearing loss or vertigo. Despite a rapidly expanding pipeline of potential cochlear therapeutics, the inner ear remains a challenging organ for targeted drug delivery, and new technologies are required to deliver these therapies in a safe and efficacious manner. In addition to traditional approaches for direct inner ear drug delivery, novel microfluidics-based systems are under development, promising improved control over pharmacokinetics over longer periods of delivery, ultimately with application towards hair cell regeneration in humans. AREAS COVERED Advances in the development of intracochlear drug delivery systems are reviewed, including passive systems, active microfluidic technologies and cochlear prosthesis-mediated delivery. This article provides a description of novel delivery systems and their potential future clinical applications in treating inner ear disease. EXPERT OPINION Recent progresses in microfluidics and miniaturization technologies are enabling the development of wearable and ultimately implantable drug delivery microsystems. Progress in this field is being spurred by the convergence of advances in molecular biology, microfluidic flow control systems and models for drug transport in the inner ear. These advances will herald a new generation of devices, with near-term applications in preclinical models, and ultimately with human clinical use for a range of diseases of the inner ear.
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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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Haghpanahi M, Gladstone MB, Zhu X, Frisina RD, Borkholder DA. Noninvasive technique for monitoring drug transport through the murine cochlea using micro-computed tomography. Ann Biomed Eng 2013; 41:2130-42. [PMID: 23636576 DOI: 10.1007/s10439-013-0816-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 04/17/2013] [Indexed: 11/28/2022]
Abstract
Local delivery of drugs to the inner ear has the potential to treat inner ear disorders including permanent hearing loss or deafness. Current mathematical models describing the pharmacokinetics of drug delivery to the inner ear have been based on large rodent studies with invasive measurements of concentration at few locations within the cochlea. Hence, estimates of clearance and diffusion parameters are based on fitting measured data with limited spatial resolution to a model. To overcome these limitations, we developed a noninvasive imaging technique to monitor and characterize drug delivery inside the mouse cochlea using micro-computed tomography (μCT). To increase the measurement accuracy, we performed a subject-atlas image registration to exploit the information readily available in the atlas image of the mouse cochlea and pass segmentation or labeling information from the atlas to our μCT scans. The approach presented here has the potential to quantify concentrations at any point along fluid-filled scalae of the inner ear. This may permit determination of spatially dependent diffusion and clearance parameters for enhanced models.
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Affiliation(s)
- Masoumeh Haghpanahi
- Department of Electrical and Microelectronic Engineering, Rochester Institute of Technology, 79 Lomb Memorial Drive, Rochester, NY 14623, USA
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Postauricular hypodermic injection to treat inner ear disorders: experimental feasibility study using magnetic resonance imaging and pharmacokinetic comparison. The Journal of Laryngology & Otology 2013; 127:239-45. [DOI: 10.1017/s0022215113000017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractBackground:To investigate the feasibility of postauricular hypodermic injection for treating inner ear disorders, we compared perilymph pharmacokinetics for postauricular versus intravenous injection, using magnetic resonance imaging, in an animal model.Methods:Twelve albino guinea pigs were divided randomly into two groups and administered gadopentetate dimeglumine via either a postauricular or an intravenous bolus injection. A 7.0 Tesla magnetic resonance imaging system was used to assess the signal intensities of gadolinium-enhanced images of the cochlea, as a biomarker for changes in gadopentetate dimeglumine concentration in the perilymph. Pharmacokinetic parameters were calculated based on these signal intensity values.Results:Guinea pigs receiving postauricular injection showed longer times to peak signal intensity, longer elimination half-life, longer mean residence time and a greater area under the signal–time curve (from pre-injection to the last time point) (p < 0.05).Conclusion:Postauricular injection shows potential as an efficient drug delivery route for the treatment of inner ear disorders.
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Pararas EEL, Borkholder DA, Borenstein JT. Microsystems technologies for drug delivery to the inner ear. Adv Drug Deliv Rev 2012; 64:1650-60. [PMID: 22386561 DOI: 10.1016/j.addr.2012.02.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 02/06/2012] [Accepted: 02/15/2012] [Indexed: 12/20/2022]
Abstract
The inner ear represents one of the most technologically challenging targets for local drug delivery, but its clinical significance is rapidly increasing. The prevalence of sensorineural hearing loss and other auditory diseases, along with balance disorders and tinnitus, has spurred broad efforts to develop therapeutic compounds and regenerative approaches to treat these conditions, necessitating advances in systems capable of targeted and sustained drug delivery. The delicate nature of hearing structures combined with the relative inaccessibility of the cochlea by means of conventional delivery routes together necessitate significant advancements in both the precision and miniaturization of delivery systems, and the nature of the molecular and cellular targets for these therapies suggests that multiple compounds may need to be delivered in a time-sequenced fashion over an extended duration. Here we address the various approaches being developed for inner ear drug delivery, including micropump-based devices, reciprocating systems, and cochlear prosthesis-mediated delivery, concluding with an analysis of emerging challenges and opportunities for the first generation of technologies suitable for human clinical use. These developments represent exciting advances that have the potential to repair and regenerate hearing structures in millions of patients for whom no currently available medical treatments exist, a situation that requires them to function with electronic hearing augmentation devices or to live with severely impaired auditory function. These advances also have the potential for broader clinical applications that share similar requirements and challenges with the inner ear, such as drug delivery to the central nervous system.
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Affiliation(s)
- Erin E Leary Pararas
- Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139, USA
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Cohen SJ, Chan RVP, Keegan M, Andreoli CM, Borenstein JT, Miller JW, Gragoudas ES. Evaluation of tissue interactions with mechanical elements of a transscleral drug delivery device. Pharmaceutics 2012; 4:212-29. [PMID: 24300189 PMCID: PMC3834904 DOI: 10.3390/pharmaceutics4010212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 02/29/2012] [Accepted: 02/29/2012] [Indexed: 01/02/2023] Open
Abstract
The goal of this work was to evaluate tissue-device interactions due to implantation of a mechanically operated drug delivery system onto the posterior sclera. Two test devices were designed and fabricated to model elements of the drug delivery device-one containing a free-spinning ball bearing and the other encasing two articulating gears. Openings in the base of test devices modeled ports for drug passage from device to sclera. Porous poly(tetrafluoroethylene) (PTFE) membranes were attached to half of the gear devices to minimize tissue ingrowth through these ports. Test devices were sutured onto rabbit eyes for 10 weeks. Tissue-device interactions were evaluated histologically and mechanically after removal to determine effects on device function and changes in surrounding tissue. Test devices were generally well-tolerated during residence in the animal. All devices encouraged fibrous tissue formation between the sclera and the device, fibrous tissue encapsulation and invasion around the device, and inflammation of the conjunctiva. Gear devices encouraged significantly greater inflammation in all cases and a larger rate of tissue ingrowth. PTFE membranes prevented tissue invasion through the covered drug ports, though tissue migrated in through other smaller openings. The torque required to turn the mechanical elements increased over 1000 times for gear devices, but only on the order of 100 times for membrane-covered gear devices and less than 100 times for ball bearing devices. Maintaining a lower device profile, minimizing microscale motion on the eye surface and covering drug ports with a porous membrane may minimize inflammation, decreasing the risk of damage to surrounding tissues and minimizing disruption of device operation.
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Affiliation(s)
- Sarah J. Cohen
- Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139, USA; (S.J.C.); (M.K.)
| | - Robison V. Paul Chan
- Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA; (R.V.P.C.); (C.M.A.); (J.W.M.); (E.S.G.)
| | - Mark Keegan
- Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139, USA; (S.J.C.); (M.K.)
| | - Christopher M. Andreoli
- Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA; (R.V.P.C.); (C.M.A.); (J.W.M.); (E.S.G.)
| | - Jeffrey T. Borenstein
- Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139, USA; (S.J.C.); (M.K.)
- Author to whom correspondence should be addressed; ; Tel.: +1-617-258-1686; Fax: +1-617-258-1131
| | - Joan W. Miller
- Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA; (R.V.P.C.); (C.M.A.); (J.W.M.); (E.S.G.)
| | - Evangelos S. Gragoudas
- Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA; (R.V.P.C.); (C.M.A.); (J.W.M.); (E.S.G.)
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Abstract
INTRODUCTION Advances in molecular biology and in the basic understanding of the mechanisms associated with sensorineural hearing loss and other diseases of the inner ear are paving the way towards new approaches for treatments for millions of patients. However, the cochlea is a particularly challenging target for drug therapy, and new technologies will be required to provide safe and efficacious delivery of these compounds. Emerging delivery systems based on microfluidic technologies are showing promise as a means for direct intracochlear delivery. Ultimately, these systems may serve as a means for extended delivery of regenerative compounds to restore hearing in patients suffering from a host of auditory diseases. AREAS COVERED Recent progress in the development of drug delivery systems capable of direct intracochlear delivery is reviewed, including passive systems such as osmotic pumps, active microfluidic devices and systems combined with currently available devices such as cochlear implants. The aim of this article is to provide a concise review of intracochlear drug delivery systems currently under development and ultimately capable of being combined with emerging therapeutic compounds for the treatment of inner ear diseases. EXPERT OPINION Safe and efficacious treatment of auditory diseases will require the development of microscale delivery devices, capable of extended operation and direct application to the inner ear. These advances will require miniaturization and integration of multiple functions, including drug storage, delivery, power management and sensing, ultimately enabling closed-loop control and timed-sequence delivery devices for treatment of these diseases.
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Affiliation(s)
- Jeffrey T Borenstein
- Biomedical Engineering Center, Draper Laboratory, Cambridge, MA 02139, United States.
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Adeno-associated virus-mediated gene delivery into the scala media of the normal and deafened adult mouse ear. Gene Ther 2011; 18:569-78. [PMID: 21209625 PMCID: PMC3085601 DOI: 10.1038/gt.2010.175] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Murine models are ideal for studying cochlear gene transfer, as many hearing loss-related mutations have been discovered and mapped within the mouse genome. However, because of the small size and delicate nature, the membranous labyrinth of the mouse is a challenging target for the delivery of viral vectors. To minimize injection trauma, we developed a procedure for the controlled release of adeno-associated viruses (AAVs) into the scala media of adult mice. This procedure poses minimal risk of injury to structures of the cochlea and middle ear, and allows for near-complete preservation of low and middle frequency hearing. In this study, transduction efficiency and cellular specificity of AAV vectors (serotypes 1, 2, 5, 6 and 8) were investigated in normal and drug-deafened ears. Using the cytomegalovirus promoter to drive gene expression, a variety of cell types were transduced successfully, including sensory hair cells and supporting cells, as well as cells in the auditory nerve and spiral ligament. Among all five serotypes, inner hair cells were the most effectively transduced cochlear cell type. All five serotypes of AAV vectors transduced cells of the auditory nerve, though serotype 8 was the most efficient vector for transduction. Our findings indicate that efficient AAV inoculation (via the scala media) can be performed in adult mouse ears, with hearing preservation a realistic goal. The procedure we describe may also have applications for intra-endolymphatic drug delivery in many mouse models of human deafness.
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