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Liu SS, Yang R. Inner Ear Drug Delivery for Sensorineural Hearing Loss: Current Challenges and Opportunities. Front Neurosci 2022; 16:867453. [PMID: 35685768 PMCID: PMC9170894 DOI: 10.3389/fnins.2022.867453] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/02/2022] [Indexed: 12/20/2022] Open
Abstract
Most therapies for treating sensorineural hearing loss are challenged by the delivery across multiple tissue barriers to the hard-to-access anatomical location of the inner ear. In this review, we will provide a recent update on various pharmacotherapy, gene therapy, and cell therapy approaches used in clinical and preclinical studies for the treatment of sensorineural hearing loss and approaches taken to overcome the drug delivery barriers in the ear. Small-molecule drugs for pharmacotherapy can be delivered via systemic or local delivery, where the blood-labyrinth barrier hinders the former and tissue barriers including the tympanic membrane, the round window membrane, and/or the oval window hinder the latter. Meanwhile, gene and cell therapies often require targeted delivery to the cochlea, which is currently achieved via intra-cochlear or intra-labyrinthine injection. To improve the stability of the biomacromolecules during treatment, e.g., RNAs, DNAs, proteins, additional packing vehicles are often required. To address the diverse range of biological barriers involved in inner ear drug delivery, each class of therapy and the intended therapeutic cargoes will be discussed in this review, in the context of delivery routes commonly used, delivery vehicles if required (e.g., viral and non-viral nanocarriers), and other strategies to improve drug permeation and sustained release (e.g., hydrogel, nanocarriers, permeation enhancers, and microfluidic systems). Overall, this review aims to capture the important advancements and key steps in the development of inner ear therapies and delivery strategies over the past two decades for the treatment and prophylaxis of sensorineural hearing loss.
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Affiliation(s)
- Sophie S. Liu
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Rong Yang
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
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Zhao Z, Han Z, Naveena K, Lei G, Qiu S, Li X, Li T, Shi X, Zhuang W, Li Y, Qiao Y, Liu H. ROS-Responsive Nanoparticle as a Berberine Carrier for OHC-Targeted Therapy of Noise-Induced Hearing Loss. ACS APPLIED MATERIALS & INTERFACES 2021; 13:7102-7114. [PMID: 33528239 DOI: 10.1021/acsami.0c21151] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Overproduction of reactive oxygen species (ROS) and inflammation are two key pathogeneses of noise-induced hearing loss (NIHL), which leads to outer hair cell (OHC) damage and hearing loss. In this work, we successfully developed ROS-responsive nanoparticles as berberine (BBR) carriers (PL-PPS/BBR) for OHC-targeted therapy of NIHL: Prestin-targeting peptide 2 (PrTP2)-modified nanoparticles (PL-PPS/BBR), which effectively accumulated in OHC areas, and poly(propylene sulfide)120 (PPS120), which scavenged ROS and converted to poly(propylene sulfoxide)120 in a ROS environment to disintegrate and provoke the rapid release of BBR with anti-inflammatory and antioxidant effects. In this study, satisfactory anti-inflammatory and antioxidant effects of PL-PPS/BBR were confirmed. Immunofluorescence and scanning electron microscopy (SEM) images showed that PL-PPS/BBR effectively accumulated in OHCs and protected the morphological integrity of OHCs. The auditory brainstem response (ABR) results demonstrated that PL-PPS/BBR significantly improved hearing in NIHL guinea pigs after noise exposure. This work suggested that PL-PPS/BBR may be a new potential treatment for noise-associated injury with clinical application.
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Affiliation(s)
- Zeqi Zhao
- Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou 221002, PR China
- Department of Otorhinolaryngology-Head and Neck Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, PR China
- Artificial Auditory Laboratory of Jiangsu Province, Xuzhou Medical University, Xuzhou 221002, PR China
| | | | - Konduru Naveena
- Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou 221002, PR China
| | - Guanxiong Lei
- Key Laboratory of Medical Imaging and Artifical Intelligence of Hunan Province, Xiangnan University, Chenzhou 423000, PR China
- Clinical College, Xiangnan University, Chenzhou 423000, PR China
| | - Shiwei Qiu
- Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou 221002, PR China
| | - Xuanyi Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, PR China
| | - Ting Li
- Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou 221002, PR China
| | - Xi Shi
- Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou 221002, PR China
| | - Wei Zhuang
- Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou 221002, PR China
| | - Yalan Li
- Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou 221002, PR China
| | - Yuehua Qiao
- Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou 221002, PR China
- Department of Otorhinolaryngology-Head and Neck Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, PR China
- Artificial Auditory Laboratory of Jiangsu Province, Xuzhou Medical University, Xuzhou 221002, PR China
| | - Hongmei Liu
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou 221002, PR China
- Department of Neurosurgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, PR China
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Nyberg S, Abbott NJ, Shi X, Steyger PS, Dabdoub A. Delivery of therapeutics to the inner ear: The challenge of the blood-labyrinth barrier. Sci Transl Med 2020; 11:11/482/eaao0935. [PMID: 30842313 DOI: 10.1126/scitranslmed.aao0935] [Citation(s) in RCA: 150] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 12/01/2017] [Accepted: 03/22/2018] [Indexed: 12/20/2022]
Abstract
Permanent hearing loss affects more than 5% of the world's population, yet there are no nondevice therapies that can protect or restore hearing. Delivery of therapeutics to the cochlea and vestibular system of the inner ear is complicated by their inaccessible location. Drug delivery to the inner ear via the vasculature is an attractive noninvasive strategy, yet the blood-labyrinth barrier at the luminal surface of inner ear capillaries restricts entry of most blood-borne compounds into inner ear tissues. Here, we compare the blood-labyrinth barrier to the blood-brain barrier, discuss invasive intratympanic and intracochlear drug delivery methods, and evaluate noninvasive strategies for drug delivery to the inner ear.
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Affiliation(s)
- Sophie Nyberg
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
| | - N Joan Abbott
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, UK
| | - Xiaorui Shi
- Oregon Hearing Research Center, Department of Otolaryngology, Head & Neck Surgery, Oregon Health & Science University, Portland, OR 97239, USA
| | - Peter S Steyger
- Oregon Hearing Research Center, Department of Otolaryngology, Head & Neck Surgery, Oregon Health & Science University, Portland, OR 97239, USA
| | - Alain Dabdoub
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada. .,Department of Otolaryngology-Head & Neck Surgery, University of Toronto, Toronto, ON M5G 2C4, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G 2C4, Canada
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Revuelta M, Santaolalla F, Arteaga O, Alvarez A, Sánchez-del-Rey A, Hilario E. Recent advances in cochlear hair cell regeneration-A promising opportunity for the treatment of age-related hearing loss. Ageing Res Rev 2017; 36:149-155. [PMID: 28414155 DOI: 10.1016/j.arr.2017.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 04/05/2017] [Accepted: 04/10/2017] [Indexed: 01/22/2023]
Abstract
The objective of this paper is to review current information regarding the treatment of age-related hearing loss by using cochlear hair cell regeneration. Recent advances in the regeneration of the inner ear, including the usefulness of stem cells, are also presented. Based on the current literature, cochlear cell regeneration may well be possible in the short term and cochlear gene therapy may also be useful for the treatment of hearing loss associated with ageing. The present review provide further insight into the pathogenesis of Inner Ear senescence and aged-related hearing loss and facilitate the development of therapeutic strategies to repair hair cells damaged by ageing. More research will be needed in order to translate them into an effective treatment for deafness linked to cochlear senescence in humans.
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Abstract
Safety pharmacology satisfies a key requirement in the process of drug development. Safety pharmacology studies are required to assess the impact of a new chemical entity (NCE) or biotechnology-derived product for human use on vital systems, such as those subserving auditory function. Safety pharmacology studies accordingly are defined as those studies that investigate the potential undesirable effects of a substance on auditory functions in relation to exposure in and above the therapeutic range. Auditory safety studies should be designed with the primary objective of determining how administration of a compound influences normal hearing. If an effect on hearing is identified, then it is necessary to determine through histopathology the underlying mechanism for the observed hearing loss. Since the auditory system contains a heterogeneous mixture of structural and cellular components that are organized in a very complex and integrated manner, it is necessary to clearly identify the underlying primary mechanism or target of the new chemical entity that produced the hearing loss. This chapter will highlight major components of auditory function with regard to potential opportunities for drug interaction. Aspects of designing ototoxicity studies will be discussed with an emphasis on standards deemed necessary by the US Food and Drug Administration. Additionally, classes of ototoxic compounds and their proposed mechanisms of action are described in depth.
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Zhai F, Liu JP, Dai CF, Wang Q, Steyger PS. Evidence-based modification of intratympanic gentamicin injections in patients with intractable vertigo. Otol Neurotol 2010; 31:642-8. [PMID: 20393376 DOI: 10.1097/mao.0b013e3181dbb30e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To compare the cochlear distribution of low-dose fluorescent gentamicin after intra-tympanic administration in guinea pig (GPs) with clinical data of low dose intra-tympanic gentamicin in patients with intractable vertigo. MATERIALS AND METHODS Purified gentamicin-Texas Red (GTTR) was injected intratympanically into GPs and the cochlear distribution and time course of GTTR fluorescence in outer hair cells (OHCs) was determined using confocal microscopy. RESULTS GTTR was rapidly taken up by OHCs, particularly in the subcuticular zone. GTTR was distributed in the cochlea in a decreasing baso-apical gradient, and was retained within OHCs without significant decrease in fluorescence until 4 weeks after injection. CONCLUSION OHCs rapidly take up GTTR after intra-tympanic administration with slow clearance. CLINICAL APPLICATION A modified low-dose titration intratympanic approach was applied to patients with intractable Ménière's Disease (MD) based on our animal data and the clinical outcome was followed. After the modified intratympanic injections for MD patients, vertigo control was achieved in 89% patients, with hearing deterioration identified in 16% patients. The 3-week interval titration injection technique thereby had a relatively high vertigo control rate with a low risk of hearing loss, and is a viable alternative to other intratympanic injection protocols.
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Affiliation(s)
- Feng Zhai
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai, China
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Salt AN. Pharmacokinetics of Drug Entry into Cochlear Fluids. THE VOLTA REVIEW 2005; 105:277-298. [PMID: 17330152 PMCID: PMC1805693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The inner ear is exposed to aminoglycosides or other drugs either intentionally or as a side effect of clinical treatments directed at other regions of the body. An understanding of the effects of drugs on the inner ear requires knowledge of the pharmacokinetics of the drug once it reaches the cochlear fluids, specifically how much of it reaches different parts of the ear and how long it stays there before disappearing. Accumulating data show that drug distribution in the inner ear is complex, especially for drugs applied locally to the ear's round window membrane. Locally applied drugs do not disperse rapidly, but instead spread very slowly through the fluid spaces by diffusion so that substantial differences in drug concentration occur in different regions of the ear. In some cases, the drug may leak from the inner ear to the blood as fast as it diffuses, meaning it may never become uniformly distributed even when applied for a long period. In recent years, experimental pharmacokinetic studies have become increasingly quantitative, permitting the results to be interpreted with computer models. Simulations of the drug distribution in animals have been used as a basis to predict the likely drug distribution in the larger, human inner ear. Such studies allow clinical drug delivery protocols to be optimized to minimize inadvertent hearing loss and to deliver therapeutic levels of the drug more effectively.
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Affiliation(s)
- Alec N Salt
- Is a professor of Otolaryngology at the Washington University School of Medicine, St. Louis, Mo
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