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Mohseni-Dargah M, Falahati Z, Pastras C, Khajeh K, Mukherjee P, Razmjou A, Stefani S, Asadnia M. Meniere's disease: Pathogenesis, treatments, and emerging approaches for an idiopathic bioenvironmental disorder. ENVIRONMENTAL RESEARCH 2023; 238:116972. [PMID: 37648189 DOI: 10.1016/j.envres.2023.116972] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 08/10/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023]
Abstract
Meniere's disease (MD) is a severe inner ear condition known by debilitating symptoms, including spontaneous vertigo, fluctuating and progressive hearing loss, tinnitus, and aural fullness or pressure within the affected ear. Prosper Meniere first described the origins of MD in the 1860s, but its underlying mechanisms remain largely elusive today. Nevertheless, researchers have identified a key histopathological feature called Endolymphatic Hydrops (ELH), which refers to the excessive buildup of endolymph fluid in the membranous labyrinth of the inner ear. The exact root of ELH is not fully understood. Still, it is believed to involve several biological and bioenvironmental etiological factors such as genetics, autoimmunity, infection, trauma, allergy, and new theories, such as saccular otoconia blocking the endolymphatic duct and sac. Regarding treatment, there are no reliable and definitive cures for MD. Most therapies focus on managing symptoms and improving the overall quality of patients' life. To make significant advancements in addressing MD, it is crucial to gain a fundamental understanding of the disease process, laying the groundwork for more effective therapeutic approaches. This paper provides a comprehensive review of the pathophysiology of MD with a focus on old and recent theories. Current treatment strategies and future translational approaches (with low-level evidence but promising results) related to MD are also discussed, including patents, drug delivery, and nanotechnology, that may provide future benefits to patients suffering from MD.
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Affiliation(s)
- Masoud Mohseni-Dargah
- School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia; Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Zahra Falahati
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
| | - Christopher Pastras
- School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia; The Meniere's Laboratory, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Khosro Khajeh
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Payal Mukherjee
- RPA Institute of Academic Surgery, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Amir Razmjou
- Centre for Technology in Water and Wastewater, University of Technology Sydney, New South Wales 2007, Australia
| | - Sebastian Stefani
- School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia
| | - Mohsen Asadnia
- School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia.
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Naveen NR, Girirajasekhar D, Goudanavar PS, Kumar CB, Narasimha GL. Prospection of Microfluidics for Local Drug Delivery. Curr Drug Targets 2022; 23:1239-1251. [PMID: 35379132 DOI: 10.2174/1389450123666220404154710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 01/03/2022] [Accepted: 02/10/2022] [Indexed: 01/25/2023]
Abstract
Significant endeavors can be made to develop effective drug delivery systems. Nowadays, many of these novel systems have gained attention as they focus primarily on increasing the bioavailability and bioaccessibility of several drugs to finally minimize the side effects, thus improving the treatment's efficacy. Microfluidics systems are unquestionably a superior technology, which is currently revolutionizing the current chemical and biological studies, providing diminutive chip-scale devices that offer precise dosage, target-precise delivery, and controlled release. Microfluidic systems have emerged as a promising delivery vehicle owing to their potential for defined handling and transporting of small liquid quantities. The latest microfabrication developments have been made for application to several biological systems. Here, we review the fundamentals of microfluidics and their application for local drug delivery.
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Affiliation(s)
- Nimbagal R Naveen
- Department of Pharmaceutics, Sri Adichunchanagiri College of Pharmacy, Adichunchanagiri University, B.G. Nagar, Karnataka 571448, India
| | | | - Prakash S Goudanavar
- Department of Pharmaceutics, Sri Adichunchanagiri College of Pharmacy, Adichunchanagiri University, B.G. Nagar, Karnataka 571448, India
| | - Chagaleti B Kumar
- Department of Pharmaceutical Chemistry, Akshaya Institute of Pharmacy, Lingapura, Tumkur, Karnataka 572106, India
| | - Gunturu L Narasimha
- Department of Pharmacy Practice, Annamacharya College of Pharmacy, New Boyanapalli, Rajampet, India
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Mohammed Y, Holmes A, Kwok PCL, Kumeria T, Namjoshi S, Imran M, Matteucci L, Ali M, Tai W, Benson HA, Roberts MS. Advances and future perspectives in epithelial drug delivery. Adv Drug Deliv Rev 2022; 186:114293. [PMID: 35483435 DOI: 10.1016/j.addr.2022.114293] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 04/09/2022] [Indexed: 12/12/2022]
Abstract
Epithelial surfaces protect exposed tissues in the body against intrusion of foreign materials, including xenobiotics, pollen and microbiota. The relative permeability of the various epithelia reflects their extent of exposure to the external environment and is in the ranking: intestinal≈ nasal ≥ bronchial ≥ tracheal > vaginal ≥ rectal > blood-perilymph barrier (otic), corneal > buccal > skin. Each epithelium also varies in their morphology, biochemistry, physiology, immunology and external fluid in line with their function. Each epithelium is also used as drug delivery sites to treat local conditions and, in some cases, for systemic delivery. The associated delivery systems have had to evolve to enable the delivery of larger drugs and biologicals, such as peptides, proteins, antibodies and biologicals and now include a range of physical, chemical, electrical, light, sound and other enhancement technologies. In addition, the quality-by-design approach to product regulation and the growth of generic products have also fostered advancement in epithelial drug delivery systems.
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Gauvin DV, McComb M, Tapp R, Yoder J, Zimmermann ZJ. Distortion Product Otoacoustic Emission Test is Not the Test to Use in Nonclinical Safety Assessment. Int J Toxicol 2022; 41:243-252. [PMID: 35443823 DOI: 10.1177/10915818221081841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Ototoxicity and ocular toxicity screening are but two examples of specialty product lines that are often employed as Tier II or III nonclinical safety/hazard screening assessments. Compared to the regulatory guidelines that govern over standard toxicology or neurotoxicology programs, there is a paucity of regulatory strategies to address these specialized product lines. With respect to ototoxicity testing, we argue for the inclusion of the "least burdensome principles" adopted by the US FDA in providing the most pragmatic, efficient, and directed identification of potential harm to auditory function in the nonclinical safety arena. We argue for the exclusive use of the auditory brainstem response and the exclusion of the distortion product otoacoustic emissions (DPOAEs) in these Tiered II safety assessment programs. The inclusion of both are a burden on operational staff and, due to the extended episodes of anesthesia required to conduct both assays, this strategy poses a health and welfare concern for the selected animal species to be used. The DPOAE does not provide any sufficiently valid or reliable data above and beyond the gold standard ABR data, followed by complete oto-histopathology and cytocochleogram combination designs.
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Affiliation(s)
| | - Margaret McComb
- Neurobehavioral Studies, 537465Charles River Laboratories, Inc., Mattawan, Mattawan, MI, USA
| | - Rachel Tapp
- Neurobehavioral Studies, 537465Charles River Laboratories, Inc., Mattawan, Mattawan, MI, USA
| | - Joshua Yoder
- Neurobehavioral Studies, 537465Charles River Laboratories, Inc., Mattawan, Mattawan, MI, USA
| | - Zachary J Zimmermann
- Neurobehavioral Studies, 537465Charles River Laboratories, Inc., Mattawan, Mattawan, MI, USA
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Schwieger J, Frisch AS, Rau TS, Lenarz T, Hügl S, Scheper V. 3D Printed Cell Culture Chamber for Testing the Effect of Pump-Based Chronic Drug Delivery on Inner Ear Tissue. Biomolecules 2022; 12:biom12040589. [PMID: 35454178 PMCID: PMC9032916 DOI: 10.3390/biom12040589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/11/2022] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
Cochlear hair cell damage and spiral ganglion neuron (SGN) degeneration are the main causes of sensory neural hearing loss. Cochlear implants (CIs) can replace the function of the hair cells and stimulate the SGNs electrically. The condition of the SGNs and their spatial distance to the CI are key factors for CI-functionality. For a better performance, a high number of neurons and a closer contact to the electrode are intended. Neurotrophic factors are able to enhance SGN survival and neurite outgrowth, and thereby might optimize the electrode-nerve interaction. This would require chronic factor treatment, which is not yet established for the inner ear. Investigations on chronic drug delivery to SGNs could benefit from an appropriate in vitro model. Thus, an inner ear inspired Neurite Outgrowth Chamber (NOC), which allows the incorporation of a mini-osmotic pump for long-term drug delivery, was designed and three-dimensionally printed. The NOC’s function was validated using spiral ganglion explants treated with ciliary neurotrophic factor, neurotrophin-3, or control fluid released via pumps over two weeks. The NOC proved to be suitable for explant cultivation and observation of pump-based drug delivery over the examined period, with neurotrophin-3 significantly increasing neurite outgrowth compared to the other groups.
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Affiliation(s)
- Jana Schwieger
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
- Correspondence: ; Tel.: +49-5115327262
| | - Anna Sophie Frisch
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
| | - Thomas S. Rau
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Silke Hügl
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Verena Scheper
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
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PLLA Coating of Active Implants for Dual Drug Release. Molecules 2022; 27:molecules27041417. [PMID: 35209205 PMCID: PMC8875406 DOI: 10.3390/molecules27041417] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 02/04/2023] Open
Abstract
Cochlear implants, like other active implants, rely on precise and effective electrical stimulation of the target tissue but become encapsulated by different amounts of fibrous tissue. The current study aimed at the development of a dual drug release from a PLLA coating and from the bulk material to address short-term and long-lasting release of anti-inflammatory drugs. Inner-ear cytocompatibility of drugs was studied in vitro. A PLLA coating (containing diclofenac) of medical-grade silicone (containing 5% dexamethasone) was developed and release profiles were determined. The influence of different coating thicknesses (2.5, 5 and 10 µm) and loadings (10% and 20% diclofenac) on impedances of electrical contacts were measured with and without pulsatile electrical stimulation. Diclofenac can be applied to the inner ear at concentrations of or below 4 × 10−5 mol/L. Release of dexamethasone from the silicone is diminished by surface coating but not blocked. Addition of 20% diclofenac enhances the dexamethasone release again. All PLLA coatings serve as insulator. This can be overcome by using removable masking on the contacts during the coating process. Dual drug release with different kinetics can be realized by adding drug-loaded coatings to drug-loaded silicone arrays without compromising electrical stimulation.
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Gröschel M, Voigt S, Schwitzer S, Ernst A, Basta D. Cytomegalovirus Seropositivity as a Potential Risk Factor for Increased Noise Trauma Susceptibility. Noise Health 2022; 24:1-6. [PMID: 35645133 PMCID: PMC9239143 DOI: 10.4103/nah.nah_4_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
CONTEXT Cytomegalovirus (CMV) represents the leading congenital viral infection in humans. Although congenital CMV due to vertically transmitted infections is the main cause of CMV-related diseases, adult CMV infections might still be of clinical significance. It is still discussed how far CMV seropositivity, due to horizontal infection in immunocompetent adults, is able to induce significant dysfunction. The present study investigates in how far CMV seropositivity is an additional risk factor for an increasing susceptibility to sensorineural hearing loss induced by acoustic injury during adulthood in a guinea pig CMV (GPCMV) model of noise-induced hearing loss (NIHL). METHODS Two groups (GPCMV seropositive vs. seronegative) of normal hearing adult guinea pigs were exposed to a broadband noise (5-20 kHz) for 2 hours at 115 dB sound pressure level. Frequency-specific auditory brainstem response recordings for determination of auditory threshold shift were carried out and the number of missing outer hair cells was counted 2 weeks after the noise exposure. RESULTS The data show a slightly increased shift in auditory thresholds in seropositive animals compared to the seronegative control group in response to noise trauma. However, the observed difference was significant at least at high frequencies. The differences in threshold shift are not correlated with outer hair cell loss between the experimental groups. CONCLUSION The results point to potential additional pathologies in a guinea pig NIHL model in correlation to GPCMV seropositivity, which should be taken into account when assessing risks of latent/reactivated CMV infection. Due to the relatively slight effect in the present data, the aim of future studies should be a more detailed consideration (e.g., larger sample size) and to localize possible target structures as well as the significance of the infection route.
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Affiliation(s)
- Moritz Gröschel
- Department of Otolaryngology at UKB, University of Berlin, Charité Medical School, Berlin, Germany,Address for correspondence: Dr Moritz Gröschel, Department of Otolaryngology, Unfallkrankenhaus Berlin, Warener Str 7, 12683 Berlin, Germany. E-mail:
| | - Stefan Voigt
- Department of Otolaryngology at UKB, University of Berlin, Charité Medical School, Berlin, Germany
| | - Susanne Schwitzer
- Department of Otolaryngology at UKB, University of Berlin, Charité Medical School, Berlin, Germany
| | - Arne Ernst
- Department of Otolaryngology at UKB, University of Berlin, Charité Medical School, Berlin, Germany
| | - Dietmar Basta
- Department of Otolaryngology at UKB, University of Berlin, Charité Medical School, Berlin, Germany
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Bile acid-permeation enhancement for inner ear cochlear drug - pharmacological uptake: bio-nanotechnologies in chemotherapy-induced hearing loss. Ther Deliv 2021; 12:807-819. [PMID: 34761700 DOI: 10.4155/tde-2021-0048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Ototoxicity is the damage to inner ear sensory epithelia due to exposure to certain medications and chemicals. This occurs when toxins enter the tightly controlled inner ear environment inducing hair cell death, resulting in hearing loss. Recent studies have explored hydrogel-based bio-nanotechnologies and new drug delivery formulations to prevent drug-induced hearing loss, with much attention given to administration of antioxidant drugs. Bile acids have been recognized as promising excipients due to their biocompatibility and unique physiochemical properties. As yet bile acids have not been explored in improving drug delivery to the inner ear despite improving drug stability and delivery in other systems and demonstrating positive biological effects in their own right.
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Verma R, Vyas P, Kaur J, Javed MN, Sarafroz M, Ahmad M, Gilani SJ, Taleuzzaman M. Approaches for ear-targeted delivery systems in neurosensory disorders to avoid chronic hearing loss mediated neurological diseases. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2021; 21:479-491. [PMID: 34477535 DOI: 10.2174/1871527320666210903102704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/17/2021] [Accepted: 04/04/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND & OBJECTIVE Hearing loss is a common audio-vestibular-related neurosensory disability of inner ears, in which patients exhibit clinical symptoms of dizziness, gait unsteadiness, and oscillopsia, at an initial stage. While, if such disorders are untreated for a prolonged duration then the progression of disease into a chronic state significantly decreases GABA level as well as an alteration in the neurotransmission of CNS systems. Hence, to control the progression of disease into a chronic state, timely and targeted delivery of the drug into the site of action in the ear is now attracting the interest of neurologists for effective and safe treatment of such disorders. Among delivery systems, owing to small dimension, better penetration, rate-controlled release, higher bioavailability; nanocarriers are preferred to overcome delivery barriers, improvement in residence time, and enhanced the performance of loaded drugs. Subsequently, these carriers also stabilize encapsulated drugs while the opportunity to modify the surface of carriers favors guided direction for site-specific targeting. Conventional routes of drug delivery such as oral. intravenous, and intramuscular are poorer in performance because of inadequate blood supply to the inner ear and limited penetration of blood-inner ear barrier. CONCLUSION This review summarized novel aspects of non-invasive and biocompatible nanoparticles-based approaches for targeted delivery of drugs into the cochlea of the ear to reduce the rate, and extent of the emergence of any hearing loss mediated neurological disorders.
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Affiliation(s)
- Rishabh Verma
- Department of Pharmacology, Faculty of Pharmacy, School of Pharmaceutical Education & Research, Jamia Hamdard, New Delhi-110062, India
| | - Preeti Vyas
- Department of Pharmacology, Faculty of Pharmacy, School of Pharmaceutical Education & Research, Jamia Hamdard, New Delhi-110062, India
| | - Jasmeet Kaur
- Department of Pharmacognosy, Faculty of Pharmacy, School of Pharmaceutical Education & Research, Jamia Hamdard, New Delhi-110062, India
| | - Md Noushad Javed
- Department of Pharmaceutics, Faculty of Pharmacy, School of Pharmaceutical Education & Research, Jamia Hamdard, New Delhi-110062, India
| | - Mohammad Sarafroz
- Department of Pharmaceutical Chemistry, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, City Dammam, Saudi Arabia
| | - Makhmur Ahmad
- Department of Pharmaceutics, Buraydah College of Pharmacy and Dentistry, P.O Box- 31717, Buraydah- 51452, Al-Qassim, Saudi Arabia
| | - Sadaf Jamal Gilani
- College of Basic Health Science, Princess Nourah bint Abdulrahman University, Riyadh. Saudi Arabia
| | - Mohamad Taleuzzaman
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Maulana Azad University, Jodhpur, 342802, Rajasthan, India
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Toulemonde P, Risoud M, Lemesre PE, Beck C, Wattelet J, Tardivel M, Siepmann J, Vincent C. Evaluation of the Efficacy of Dexamethasone-Eluting Electrode Array on the Post-Implant Cochlear Fibrotic Reaction by Three-Dimensional Immunofluorescence Analysis in Mongolian Gerbil Cochlea. J Clin Med 2021; 10:jcm10153315. [PMID: 34362099 PMCID: PMC8347204 DOI: 10.3390/jcm10153315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 11/16/2022] Open
Abstract
Cochlear implant is the method of choice for the rehabilitation of severe to profound sensorineural hearing loss. The study of the tissue response to cochlear implantation and the prevention of post-cochlear-implant damages are areas of interest in hearing protection research. The objective was to assess the efficacy of dexamethasone-eluting electrode array on endo canal fibrosis formation by three-dimensional immunofluorescence analysis in implanted Mongolian gerbil cochlea. Two trials were conducted after surgery using Mongolian gerbil implanted with dexamethasone-eluting or non-eluting intracochlear electrode arrays. The animals were then euthanised 10 weeks after implantation. The cochleae were prepared (electrode array in place) according to a 29-day protocol with immunofluorescent labelling and tissue clearing. The acquisition was carried out using light-sheet microscopy. Imaris software was then used for three-dimensional analysis of the cochleae and quantification of the fibrotic volume. The analysis of 12 cochleae showed a significantly different mean volume of fibrosis (2.16 × 108 μm3 ± 0.15 in the dexamethasone eluting group versus 3.17 × 108 μm3 ± 0.54 in the non-eluting group) (p = 0.004). The cochlear implant used as a corticosteroid delivery system appears to be an encouraging device for the protection of the inner ear against fibrosis induced by implantation. Three-dimensional analysis of the cochlea by light-sheet microscopy was suitable for studying post-implantation tissue damage.
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Affiliation(s)
- Philippine Toulemonde
- Department of Otology and Neurotology, CHU Lille, University of Lille 2 Henri Warembourg, F-59000 Lille, France; (M.R.); (P.E.L.); (C.B.); (J.W.); (J.S.); (C.V.)
- INSERM U1008—Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
- Correspondence: ; Tel.: +33-6851-91052
| | - Michaël Risoud
- Department of Otology and Neurotology, CHU Lille, University of Lille 2 Henri Warembourg, F-59000 Lille, France; (M.R.); (P.E.L.); (C.B.); (J.W.); (J.S.); (C.V.)
- INSERM U1008—Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - Pierre Emmanuel Lemesre
- Department of Otology and Neurotology, CHU Lille, University of Lille 2 Henri Warembourg, F-59000 Lille, France; (M.R.); (P.E.L.); (C.B.); (J.W.); (J.S.); (C.V.)
- INSERM U1008—Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - Cyril Beck
- Department of Otology and Neurotology, CHU Lille, University of Lille 2 Henri Warembourg, F-59000 Lille, France; (M.R.); (P.E.L.); (C.B.); (J.W.); (J.S.); (C.V.)
- INSERM U1008—Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - Jean Wattelet
- Department of Otology and Neurotology, CHU Lille, University of Lille 2 Henri Warembourg, F-59000 Lille, France; (M.R.); (P.E.L.); (C.B.); (J.W.); (J.S.); (C.V.)
- INSERM U1008—Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - Meryem Tardivel
- BioImaging Center Lille-Nord de France (BICeL), University of Lille 2 Henri Warembourg, F-59000 Lille, France;
| | - Juergen Siepmann
- Department of Otology and Neurotology, CHU Lille, University of Lille 2 Henri Warembourg, F-59000 Lille, France; (M.R.); (P.E.L.); (C.B.); (J.W.); (J.S.); (C.V.)
- INSERM U1008—Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - Christophe Vincent
- Department of Otology and Neurotology, CHU Lille, University of Lille 2 Henri Warembourg, F-59000 Lille, France; (M.R.); (P.E.L.); (C.B.); (J.W.); (J.S.); (C.V.)
- INSERM U1008—Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
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Abstract
The delivery of therapies to the cochlea is notoriously challenging. It is an organ protected by a number of barriers that need to be overcome in the drug delivery process. Additionally, there are multiple sites of possible damage within the cochlea. Despite the many potential sites of damage, acquired otologic insults preferentially damage a single location. While progress has been made in techniques for inner ear drug delivery, the current techniques remain non-specific and our ability to deliver therapies in a cell-specific manner are limited. Fortunately, there are proteins specific to various cell-types within the cochlea (e.g., hair cells, spiral ganglion cells, stria vascularis) that function as biomarkers of site-specific damage. These protein biomarkers have potential to serve as targets for cell-specific inner ear drug delivery. In this manuscript, we review the concept of biomarkers and targeted- inner ear drug delivery and the well-characterized protein biomarkers within each of the locations of interest within the cochlea. Our review will focus on targeted drug delivery in the setting of acquired otologic insults (e.g., ototoxicity, noise-induce hearing loss). The goal is not to discuss therapies to treat acquired otologic insults, rather, to establish potential concepts of how to deliver therapies in a targeted, cell-specific manner. Based on our review, it is clear that future of inner ear drug delivery is a discipline filled with potential that will require collaborative efforts among clinicians and scientists to optimize treatment of otologic insults. Graphical Abstract ![]()
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Anatomical and Functional Consequences of Microneedle Perforation of Round Window Membrane. Otol Neurotol 2020; 41:e280-e287. [DOI: 10.1097/mao.0000000000002491] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Rathnam C, Chueng STD, Ying YLM, Lee KB, Kwan K. Developments in Bio-Inspired Nanomaterials for Therapeutic Delivery to Treat Hearing Loss. Front Cell Neurosci 2019; 13:493. [PMID: 31780898 PMCID: PMC6851168 DOI: 10.3389/fncel.2019.00493] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 10/21/2019] [Indexed: 01/10/2023] Open
Abstract
Sensorineural hearing loss affects millions of people worldwide and is a growing concern in the aging population. Treatment using aminoglycoside antibiotics for infection and exposure to loud sounds contribute to the degeneration of cochlear hair cells and spiral ganglion neurons. Cell loss impacts cochlear function and causes hearing loss in ∼ 15% of adult Americans (∼36 million). The number of individuals with hearing loss will likely grow with increasing lifespans. Current prosthesis such as hearing aids and cochlear implants can ameliorate hearing loss. However, hearing aids are ineffective if hair cells or spiral ganglion neurons are severely damaged, and cochlear implants are ineffective without properly functioning spiral ganglion neurons. As such, strategies that alleviate hearing loss by preventing degeneration or promoting cell replacement are urgently needed. Despite showing great promise from in vitro studies, the complexity and delicate nature of the inner ear poses a huge challenge for delivering therapeutics. To mitigate risks and complications associated with surgery, new technologies and methodologies have emerged for efficient delivery of therapeutics. We will focus on biomaterials that allow controlled and local drug delivery into the inner ear. The rapid development of microsurgical techniques in conjunction with novel bio- and nanomaterials for sustained drug delivery appears bright for hearing loss treatment.
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Affiliation(s)
- Christopher Rathnam
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - Sy-Tsong Dean Chueng
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - Yu-Lan Mary Ying
- Department of Otolaryngology Head and Neck Surgery, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Ki-Bum Lee
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, United States.,Stem Cell Research Center and Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - Kelvin Kwan
- Stem Cell Research Center and Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States.,Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
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14
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Leterme G, Guigou C, Oudot A, Collin B, Boudon J, Millot N, Geissler A, Belharet K, Bozorg Grayeli A. Superparamagnetic Nanoparticle Delivery to the Cochlea Through Round Window by External Magnetic Field: Feasibility and Toxicity. Surg Innov 2019; 26:646-655. [PMID: 31478462 DOI: 10.1177/1553350619867217] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Introduction. The objective of this study was to evaluate the feasibility and toxicity of superparamagnetic iron oxide nanoparticles (SPIONs) administered into the cochlea through the round window (RW) by an external magnetic field. Materials and Methods. In 5 Wistar rats, the left RW was punctured. SPIONs suspended in hyaluronic gel (5 mg/mL) were applied in the RW niche and covered by a muscle graft. The nanoparticles were mobilized using a rare earth magnet (0.54 T) held in 4 consecutive positions around the head. The right ear served as control. Hearing function was monitored by auditory brainstem responses (4-32 kHz tone bursts). Results. The auditory thresholds remained unchanged 1 month after the administration. The histological study of the cochleae showed that SPIONs were driven into the scala tympani in the basal turn, the second turn, and the apex. Conclusion. Superparamagnetic nanoparticles can be driven inside the cochlea toward the apex with a preserved hearing up to 1 month in rats.
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Affiliation(s)
- Gaëlle Leterme
- Otolaryngology Department, Dijon University Hospital, Dijon, France.,Laboratoire Imvia, Université Bourgogne-Franche-Comté, Dijon, France
| | - Caroline Guigou
- Otolaryngology Department, Dijon University Hospital, Dijon, France.,Laboratoire Imvia, Université Bourgogne-Franche-Comté, Dijon, France
| | | | - Bertrand Collin
- Centre Georges François Leclerc, Dijon, France.,ICMUB, UMR 6302 CNRS/Université Bourgogne Franche-Comté, Dijon, France
| | - Julien Boudon
- Laboratoire ICB, UMR 6303 CNRS/Université Bourgogne Franche-Comté, Dijon, France
| | - Nadine Millot
- Laboratoire ICB, UMR 6303 CNRS/Université Bourgogne Franche-Comté, Dijon, France
| | - Audrey Geissler
- Plateforme d'imagerie cellulaire CellImaP, Université Bourgogne-Franche-Comté, Dijon, France
| | - Karim Belharet
- Laboratoire PRISME, HEI Campus Centre, Châteauroux, France
| | - Alexis Bozorg Grayeli
- Otolaryngology Department, Dijon University Hospital, Dijon, France.,Laboratoire Imvia, Université Bourgogne-Franche-Comté, Dijon, France
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15
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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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16
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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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Shimoji M, Ramaswamy B, Shukoor MI, Benhal P, Broda A, Kulkarni S, Malik P, McCaffrey B, Lafond JF, Nacev A, Weinberg IN, Shapiro B, Depireux DA. Toxicology study for magnetic injection of prednisolone into the rat cochlea. Eur J Pharm Sci 2019; 126:33-48. [PMID: 29933075 PMCID: PMC6235712 DOI: 10.1016/j.ejps.2018.06.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/31/2018] [Accepted: 06/12/2018] [Indexed: 01/28/2023]
Abstract
This paper investigates the safety of a novel 'magnetic injection' method of delivering therapy to the cochlea, in a rodent model. In this method of administration, a magnetic field is employed to actively transport drug-eluting superparamagnetic iron-oxide core nanoparticles into the cochlea, where they then release their drug payload (we delivered the steroid prednisolone). Our study design and selection of control groups was based on published regulatory guidance for safety studies that involve local drug delivery. We tested for both single and multiple delivery doses to the cochlea, and found that magnetic delivery did not harm hearing. There was no statistical difference in hearing between magnetically treated ears versus ears that received intra-tympanic steroid (a mimic of a standard-of-care for sudden sensorineural hearing loss), both 2 and 30 days after treatment. Since our treatment is local to the ear, the levels of steroid and iron circulating systemically after our treatment were low, below mass-spectrometry detection limits for the steroid and no different from normal for iron. No adverse findings were observed in ear tissue histopathology or in animal gross behavior. At 2 and 30 days after treatment, inflammatory changes examined in the ear were limited to the middle ear, were very mild in severity, and by day 90 there was ongoing and almost complete reversibility of these changes. There were no ear tissue scarring or hemorrhage trends associated with magnetic delivery. In summary, after conducting a pre-clinical safety study, no adverse safety issues were observed.
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Affiliation(s)
- M Shimoji
- Otomagnetics, Inc., Rockville, MD 20852, United States of America.
| | - B Ramaswamy
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America
| | - M I Shukoor
- Otomagnetics, Inc., Rockville, MD 20852, United States of America
| | - P Benhal
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America
| | - A Broda
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America
| | - S Kulkarni
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America
| | - P Malik
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America
| | - B McCaffrey
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America
| | | | - A Nacev
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America
| | - I N Weinberg
- Otomagnetics, Inc., Rockville, MD 20852, United States of America
| | - B Shapiro
- Otomagnetics, Inc., Rockville, MD 20852, United States of America; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America; Institute for Systems Research (ISR), University of Maryland, College Park, MD 20742, United States of America
| | - D A Depireux
- Otomagnetics, Inc., Rockville, MD 20852, United States of America; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America; Institute for Systems Research (ISR), University of Maryland, College Park, MD 20742, United States of America
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18
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Liu X, Li M, Smyth H, Zhang F. Otic drug delivery systems: formulation principles and recent developments. Drug Dev Ind Pharm 2018; 44:1395-1408. [PMID: 29659300 DOI: 10.1080/03639045.2018.1464022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Disorders of the ear severely impact the quality of life of millions of people, but the treatment of these disorders is an ongoing, but often overlooked challenge particularly in terms of formulation design and product development. The prevalence of ear disorders has spurred significant efforts to develop new therapeutic agents, but perhaps less innovation has been applied to new drug delivery systems to improve the efficacy of ear disease treatments. This review provides a brief overview of physiology, major diseases, and current therapies used via the otic route of administration. The primary focuses are on the various administration routes and their formulation principles. The article also presents recent advances in otic drug deliveries as well as potential limitations. Otic drug delivery technology will likely evolve in the next decade and more efficient or specific treatments for ear disease will arise from the development of less invasive drug delivery methods, safe and highly controlled drug delivery systems, and biotechnology targeting therapies.
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Affiliation(s)
- Xu Liu
- a College of Pharmacy , The University of Texas at Austin , Austin , TX , USA
| | - Mingshuang Li
- b Department of Communication Sciences and Disorders , The University of Texas at Austin , Austin , TX , USA
| | - Hugh Smyth
- a College of Pharmacy , The University of Texas at Austin , Austin , TX , USA
| | - Feng Zhang
- a College of Pharmacy , The University of Texas at Austin , Austin , TX , USA
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19
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Mäder K, Lehner E, Liebau A, Plontke SK. Controlled drug release to the inner ear: Concepts, materials, mechanisms, and performance. Hear Res 2018; 368:49-66. [PMID: 29576310 DOI: 10.1016/j.heares.2018.03.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/21/2018] [Accepted: 03/06/2018] [Indexed: 12/01/2022]
Abstract
Progress in drug delivery to the ear has been achieved over the last few years. This review illustrates the main mechanisms of controlled drug release and the resulting geometry- and size-dependent release kinetics. The potency, physicochemical properties, and stability of the drug molecules are key parameters for designing the most suitable drug delivery system. The most important drug delivery systems for the inner ear include solid foams, hydrogels, and different nanoscale drug delivery systems (e.g., nanoparticles, liposomes, lipid nanocapsules, polymersomes). Their main characteristics (i.e., general structure and materials) are discussed, with special attention given to underlining the link between the physicochemical properties (e.g., surface areas, glass transition temperature, microviscosity, size, and shape) and release kinetics. An appropriate characterization of the drug, the excipients used, and the formulated drug delivery systems is necessary to achieve a deeper understanding of the release process and decrease variability originating from the drug delivery system. This task cannot be solved by otologists alone. The interdisciplinary cooperation between otology/neurotology, pharmaceutics, physics, and other disciplines will result in improved drug delivery systems for the inner ear.
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Affiliation(s)
- Karsten Mäder
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, D-06120 Halle (Saale), Germany.
| | - Eric Lehner
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, D-06120 Halle (Saale), Germany
| | - Arne Liebau
- Department of Otorhinolaryngology, Head & Neck Surgery, Martin Luther University Halle-Wittenberg, University Medicine Halle, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
| | - Stefan K Plontke
- Department of Otorhinolaryngology, Head & Neck Surgery, Martin Luther University Halle-Wittenberg, University Medicine Halle, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
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20
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Abstract
Local drug application to the inner ear offers a number of advantages over systemic delivery. Local drug therapy currently encompasses extracochlear administration (i. e., through intratympanic injection), intracochlear administration (particularly for gene and stem cell therapy), as well as various combinations with auditory neurosensory prostheses, either evaluated in preclinical or clinical studies, or off-label. To improve rehabilitation with cochlear implants (CI), one focus is the development of drug-releasing electrode carriers, e. g., for delivery of glucocorticosteroids, antiapoptotic substances, or neurotrophins to the inner ear. The performance of cochlear implants may thus be improved by protecting neuronal structures from insertion trauma, reducing fibrosis in the inner ear, and by stimulating growth of neuronal structures in the direction of the electrodes. Controlled drug release after extracochlear or intracochlear application in conjunction with a CI can also be achieved by use of a biocompatible, resorbable controlled-release drug-delivery system. Two case reports for intracochlear controlled release drug delivery in combination with cochlear implants are presented. In order to treat progressive reduction in speech discrimination and increased impedance, two cochlear implant patients successfully underwent intracochlear placement of a biocompatible, resorbable drug-delivery system for controlled release of dexamethasone. The drug levels reached in inner ear fluids after different types of local drug application strategies can be calculated using a computer model. The intracochlear drug concentrations calculated in this way were compared for different dexamethasone application strategies.
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21
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Dai C, Lehar M, Sun DQ, Rvt LS, Carey JP, MacLachlan T, Brough D, Staecker H, Della Santina AM, Hullar TE, Della Santina CC. Rhesus Cochlear and Vestibular Functions Are Preserved After Inner Ear Injection of Saline Volume Sufficient for Gene Therapy Delivery. J Assoc Res Otolaryngol 2017. [PMID: 28646272 DOI: 10.1007/s10162-017-0628-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Sensorineural losses of hearing and vestibular sensation due to hair cell dysfunction are among the most common disabilities. Recent preclinical research demonstrates that treatment of the inner ear with a variety of compounds, including gene therapy agents, may elicit regeneration and/or repair of hair cells in animals exposed to ototoxic medications or other insults to the inner ear. Delivery of gene therapy may also offer a means for treatment of hereditary hearing loss. However, injection of a fluid volume sufficient to deliver an adequate dose of a pharmacologic agent could, in theory, cause inner ear trauma that compromises functional outcome. The primary goal of the present study was to assess that risk in rhesus monkeys, which closely approximates humans with regard to middle and inner ear anatomy. Secondary goals were to identify the best delivery route into the primate ear from among two common surgical approaches (i.e., via an oval window stapedotomy and via the round window) and to determine the relative volumes of rhesus, rodent, and human labyrinths for extrapolation of results to other species. We measured hearing and vestibular functions before and 2, 4, and 8 weeks after unilateral injection of phosphate-buffered saline vehicle (PBSV) into the perilymphatic space of normal rhesus monkeys at volumes sufficient to deliver an atoh1 gene therapy vector. To isolate effects of injection, PBSV without vector was used. Assays included behavioral observation, auditory brainstem responses, distortion product otoacoustic emissions, and scleral coil measurement of vestibulo-ocular reflexes during whole-body rotation in darkness. Three groups (N = 3 each) were studied. Group A received a 10 μL transmastoid/trans-stapes injection via a laser stapedotomy. Group B received a 10 μL transmastoid/trans-round window injection. Group C received a 30 μL transmastoid/trans-round window injection. We also measured inner ear fluid space volume via 3D reconstruction of computed tomography (CT) images of adult C57BL6 mouse, rat, rhesus macaque, and human temporal bones (N = 3 each). Injection was well tolerated by all animals, with eight of nine exhibiting no signs of disequilibrium and one animal exhibiting transient disequilibrium that resolved spontaneously by 24 h after surgery. Physiologic results at the final, 8-week post-injection measurement showed that injection was well tolerated. Compared to its pretreatment values, no treated ear's ABR threshold had worsened by more than 5 dB at any stimulus frequency; distortion product otoacoustic emissions remained detectable above the noise floor for every treated ear (mean, SD and maximum deviation from baseline: -1.3, 9.0, and -18 dB, respectively); and no animal exhibited a reduction of more than 3 % in vestibulo-ocular reflex gain during high-acceleration, whole-body, passive yaw rotations in darkness toward the treated side. All control ears and all operated ears with definite histologic evidence of injection through the intended site showed similar findings, with intact hair cells in all five inner ear sensory epithelia and intact auditory/vestibular neurons. The relative volumes of mouse, rat, rhesus, and human inner ears as measured by CT were (mean ± SD) 2.5 ± 0.1, 5.5 ± 0.4, 59.4 ± 4.7 and 191.1 ± 4.7 μL. These results indicate that injection of PBSV at volumes sufficient for gene therapy delivery can be accomplished without destruction of inner ear structures required for hearing and vestibular sensation.
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Affiliation(s)
- Chenkai Dai
- Vestibular NeuroEngineering Lab, Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA. .,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA.
| | - Mohamed Lehar
- Vestibular NeuroEngineering Lab, Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA
| | - Daniel Q Sun
- Vestibular NeuroEngineering Lab, Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA
| | - Lani Swarthout Rvt
- Vestibular NeuroEngineering Lab, Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA
| | - John P Carey
- Vestibular NeuroEngineering Lab, Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA
| | - Tim MacLachlan
- Novartis Institutes for Biomedical Research, 250 Massachusetts Ave, Cambridge, MA, 02139, USA
| | - Doug Brough
- GenVec, 910 Clopper Rd #220n, Gaithersburg, MD, 20878, USA
| | - Hinrich Staecker
- Dept of Otolaryngology, Head & Neck Surgery, University of Kansas School of Medicine, 3901 Rainbow Blvd, Kansas City, KS, 66160, USA
| | - Alexandra M Della Santina
- Vestibular NeuroEngineering Lab, Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA
| | - Timothy E Hullar
- Department of Otolaryngology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO, 63110, USA.,Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO, 63110, USA.,Department of Audiology and Communication Sciences, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO, 63110, USA
| | - Charles C Della Santina
- Vestibular NeuroEngineering Lab, Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave., Ross Bldg Rm 830, Baltimore, MD, 21205, USA
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22
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Gurman P, Elman N, Rosen Y. Drug Delivery Systems. Drug Deliv 2017. [DOI: 10.1201/9781315117584-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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24
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Yoon JY, Yang KJ, Kim DE, Lee KY, Park SN, Kim DK, Kim JD. Intratympanic delivery of oligoarginine-conjugated nanoparticles as a gene (or drug) carrier to the inner ear. Biomaterials 2015; 73:243-53. [DOI: 10.1016/j.biomaterials.2015.09.025] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 09/15/2015] [Indexed: 01/12/2023]
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25
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Novel High Content Screen Detects Compounds That Promote Neurite Regeneration from Cochlear Spiral Ganglion Neurons. Sci Rep 2015; 5:15960. [PMID: 26521685 PMCID: PMC4629150 DOI: 10.1038/srep15960] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 10/06/2015] [Indexed: 12/21/2022] Open
Abstract
The bipolar spiral ganglion neurons (SGN) carry sound information from cochlear hair cells to the brain. After noise, antibiotic or toxic insult to the cochlea, damage to SGN and/or hair cells causes hearing impairment. Damage ranges from fiber and synapse degeneration to dysfunction and loss of cells. New interventions to regenerate peripheral nerve fibers could help reestablish transfer of auditory information from surviving or regenerated hair cells or improve results from cochlear implants, but the biochemical mechanisms to target are largely unknown. Presently, no drugs exist that are FDA approved to stimulate the regeneration of SGN nerve fibers. We designed an original phenotypic assay to screen 440 compounds of the NIH Clinical Collection directly on dissociated mouse spiral ganglia. The assay detected one compound, cerivastatin, that increased the length of regenerating neurites. The effect, mimicked by other statins at different optimal concentrations, was blocked by geranylgeraniol. These results demonstrate the utility of screening small compound libraries on mixed cultures of dissociated primary ganglia. The success of this screen narrows down a moderately sized library to a single compound which can be elevated to in-depth in vivo studies, and highlights a potential new molecular pathway for targeting of hearing loss drugs.
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26
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Gurman P, Miranda OR, Clayton K, Rosen Y, Elman NM. Clinical applications of biomedical microdevices for controlled drug delivery. Mayo Clin Proc 2015; 90:93-108. [PMID: 25484235 DOI: 10.1016/j.mayocp.2014.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/11/2014] [Accepted: 10/02/2014] [Indexed: 01/20/2023]
Abstract
Miniaturization of devices to micrometer and nanometer scales, combined with the use of biocompatible and functional materials, has created new opportunities for the implementation of drug delivery systems. Advances in biomedical microdevices for controlled drug delivery platforms promise a new generation of capabilities for the treatment of acute conditions and chronic illnesses, which require high adherence to treatment, in which temporal control over the pharmacokinetic profiles is critical. In addition, clinical conditions that require a combination of drugs with specific pharmacodynamic profiles and local delivery will benefit from drug delivery microdevices. This review provides a summary of various clinical applications for state-of-the-art controlled drug delivery microdevices, including cancer, endocrine and ocular disorders, and acute conditions such as hemorrhagic shock. Regulatory considerations for clinical translation of drug delivery microdevices are also discussed. Drug delivery microdevices promise a remarkable gain in clinical outcomes and a substantial social impact. A review of articles covering the field of microdevices for drug delivery was performed between January 1, 1990, and January 1, 2014, using PubMed as a search engine.
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Affiliation(s)
- Pablo Gurman
- Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge; Department of Materials Science, University of Texas at Dallas, Richardson
| | - Oscar R Miranda
- Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge
| | - Kevin Clayton
- Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge
| | - Yitzhak Rosen
- Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge
| | - Noel M Elman
- Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge.
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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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Maina JW, Cui J, Björnmalm M, Wise AK, Shepherd RK, Caruso F. Mold-templated inorganic-organic hybrid supraparticles for codelivery of drugs. Biomacromolecules 2014; 15:4146-51. [PMID: 25321318 DOI: 10.1021/bm501171j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
This paper reports a facile and robust mold-templated technique for the assembly of mesoporous silica (MS) supraparticles and demonstrates their potential as vehicles for codelivery of brain-derived neurotrophic factor (BDNF) and dexamethasone (DEX). The MS supraparticles are assembled using gelatin as a biodegradable adhesive to bind and cross-link the particles. Microfabricated molds made of polydimethylsiloxane are used to control the size and shape of the supraparticles. The obtained mesoporous silica-gelatin hybrid supraparticles (MSG-SPs) are stable in water as well as in organic solvents, such as dimethyl sulfoxide, and efficiently coencapsulate both BDNF and DEX. The MSG-SPs also exhibit sustained release kinetics in simulated physiological conditions (>30 days), making them potential candidates for long-term delivery of therapeutics to the inner ear.
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Affiliation(s)
- James W Maina
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, ‡Department of Chemical and Biomolecular Engineering, §Department of Otolaryngology, and ∥Department of Medical Bionics, The University of Melbourne , Parkville, Victoria 3010, Australia
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29
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Hütten M, Dhanasingh A, Hessler R, Stöver T, Esser KH, Möller M, Lenarz T, Jolly C, Groll J, Scheper V. In vitro and in vivo evaluation of a hydrogel reservoir as a continuous drug delivery system for inner ear treatment. PLoS One 2014; 9:e104564. [PMID: 25105670 PMCID: PMC4126769 DOI: 10.1371/journal.pone.0104564] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 07/10/2014] [Indexed: 12/20/2022] Open
Abstract
Fibrous tissue growth and loss of residual hearing after cochlear implantation can be reduced by application of the glucocorticoid dexamethasone-21-phosphate-disodium-salt (DEX). To date, sustained delivery of this agent to the cochlea using a number of pharmaceutical technologies has not been entirely successful. In this study we examine a novel way of continuous local drug application into the inner ear using a refillable hydrogel functionalized silicone reservoir. A PEG-based hydrogel made of reactive NCO-sP(EO-stat-PO) prepolymers was evaluated as a drug conveying and delivery system in vitro and in vivo. Encapsulating the free form hydrogel into a silicone tube with a small opening for the drug diffusion resulted in delayed drug release but unaffected diffusion of DEX through the gel compared to the free form hydrogel. Additionally, controlled DEX release over several weeks could be demonstrated using the hydrogel filled reservoir. Using a guinea-pig cochlear trauma model the reservoir delivery of DEX significantly protected residual hearing and reduced fibrosis. As well as being used as a device in its own right or in combination with cochlear implants, the hydrogel-filled reservoir represents a new drug delivery system that feasibly could be replenished with therapeutic agents to provide sustained treatment of the inner ear.
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Affiliation(s)
- Mareike Hütten
- Department of Otolaryngology, Hannover School of Medicine, Hannover, Germany
- University of Veterinary Medicine Hannover, Foundation, Institute of Zoology, Hannover, Germany
| | - Anandhan Dhanasingh
- MED-EL Innsbruck, Research & Development, Innsbruck, Österreich
- Interactive Materials Research–DWI e.V. and Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen, Germany
| | - Roland Hessler
- MED-EL Innsbruck, Research & Development, Innsbruck, Österreich
| | - Timo Stöver
- J.W. Goethe University Hospital and Faculty of Medicine, Department of Otolaryngology, Frankfurt am Main, Germany
| | - Karl-Heinz Esser
- University of Veterinary Medicine Hannover, Foundation, Institute of Zoology, Hannover, Germany
| | - Martin Möller
- Interactive Materials Research–DWI e.V. and Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover School of Medicine, Hannover, Germany
| | - Claude Jolly
- MED-EL Innsbruck, Research & Development, Innsbruck, Österreich
| | - Jürgen Groll
- Interactive Materials Research–DWI e.V. and Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen, Germany
- University of Würzburg, Department of Functional Materials in Medicine and Dentistry, Würzburg, Germany
- * E-mail: (JG); (VS)
| | - Verena Scheper
- Department of Otolaryngology, Hannover School of Medicine, Hannover, Germany
- Institute of Audioneurotechnology, Hannover School of Medicine, Hannover, Germany
- * E-mail: (JG); (VS)
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Design, fabrication and characterization of drug delivery systems based on lab-on-a-chip technology. Adv Drug Deliv Rev 2013; 65:1403-19. [PMID: 23726943 DOI: 10.1016/j.addr.2013.05.008] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/16/2013] [Accepted: 05/22/2013] [Indexed: 11/23/2022]
Abstract
Lab-on-a-chip technology is an emerging field evolving from the recent advances of micro- and nanotechnologies. The technology allows the integration of various components into a single microdevice. Microfluidics, the science and engineering of fluid flow in microscale, is the enabling underlying concept for lab-on-a-chip technology. The present paper reviews the design, fabrication and characterization of drug delivery systems based on this amazing technology. The systems are categorized and discussed according to the scales at which the drug is administered. Starting with the fundamentals on scaling laws of mass transfer and basic fabrication techniques, the paper reviews and discusses drug delivery devices for cellular, tissue and organism levels. At the cellular level, a concentration gradient generator integrated with a cell culture platform is the main drug delivery scheme of interest. At the tissue level, the synthesis of smart particles as drug carriers using lab-on-a-chip technology is the main focus of recent developments. At the organism level, microneedles and implantable devices with fluid-handling components are the main drug delivery systems. For drug delivery to a small organism that can fit into a microchip, devices similar to those of cellular level can be used.
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Wrzeszcz A, Reuter G, Nolte I, Lenarz T, Scheper V. Spiral ganglion neuron quantification in the guinea pig cochlea using Confocal Laser Scanning Microscopy compared to embedding methods. Hear Res 2013; 306:145-55. [PMID: 23968822 DOI: 10.1016/j.heares.2013.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/10/2013] [Accepted: 08/06/2013] [Indexed: 12/16/2022]
Abstract
Neuron counting in the cochlea is a crucial but time-consuming operation for which various methods have been developed. To improve simplicity and efficiency, we tested an imaging method of the cochlea, and based on Confocal Laser Scanning Microscopy (CLSM), we visualised Rosenthal's Canal and quantified the spiral ganglion neurons (SGN) within. Cochleae of 8 normal hearing guinea pigs and one implanted with a silicone filament were fixed in paraformaldehyde (PFA), decalcified, dehydrated and cleared in Spalteholz solution. Using the tissue's autofluorescence, CLSM was performed at 100 fold magnification generating z-series stacks of about 20 slices of the modiolus. In 5 midmodiolar slices per cochlea the perimeters of the Rosenthal's Canal were surveyed, representative neuron diameters were measured and the neurons first counted manually and then software-assisted. For comparison, 8 normal hearing guinea pig cochleae were embedded in paraffin and examined similarly. The CLSM method has the advantage that the cochleae remain intact as an organ and keep their geometrical structure. Z-stack creation is nearly fully-automatic and frequently repeatable with various objectives and step sizes and without visible bleaching. The tissue shows minimal or no shrinking artefacts and damage typical of embedding and sectioning. As a result, the cells in the cleared cochleae reach an average diameter of 21 μm and a density of about 18 cells/10,000 μm(2) with no significant difference between the manual and the automatical counts. Subsequently we compared the CLSM data with those generated using the established method of paraffin slides, where the SGN reached a mean density of 9.5 cells/10,000 μm(2) and a mean soma diameter of 13.6 μm. We were able to prove that the semi-automatic CLSM method is a simple and effective technique for auditory neuron count. It provides a high grade of tissue preservation and the automatic stack-generation as well as the counter software reduces the effort considerably. In addition this visualisation technique offers the potential to detect the position and orientation of cochlear implants (CI) within the cochlea and tissue growing in the scala tympani around the CI and at the position of the cochleostomy due to the fact that the implant does not have to be removed to perform histology as in case of the paraffin method.
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Affiliation(s)
- Antonina Wrzeszcz
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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Hütten M, Ehrhart F, Erhacrt F, Zimmermann H, Reich U, Esser KH, Lenarz T, Scheper V. UHV-alginate as matrix for neurotrophic factor producing cells--a novel biomaterial for cochlear implant optimization to preserve inner ear neurons from degeneration. Otol Neurotol 2013; 34:1127-33. [PMID: 23512074 DOI: 10.1097/mao.0b013e3182804949] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Ultra high viscous (UHV-) alginate is a suitable matrix for brain-derived neurotrophic factor (BDNF) producing cells, enabling cell survival and BDNF release out of the matrix and subsequent protection of auditory neuronal cells. BACKGROUND Cochlear implant (CI) target cells, spiral ganglion cells (SGC), undergo a progressive degeneration. BDNF prevents SGC from degeneration but has to be delivered locally to the inner ear for months. A permanent growth factor application may be realized via a cell-based drug delivery system. Encapsulation of this delivery system into a matrix could avoid immune response of the recipient, migration, and uncontrolled proliferation of the cells. METHODS NIH3T3-fibroblasts producing endogenous BDNF were incorporated in UHV-alginate. The survival of the cells in the alginate was examined by cell counts of cryogenic slices, and the BDNF production was determined by performing ELISA. The supernatant of the alginate-cell culture was added to primary SGC culture, and the neuroprotective effect of the produced BDNF was observed performing SGC counts. RESULTS BDNF-producing cells cultivated in UHV-alginate survived for up to 30 days, which was the latest time point observed. The BDNF concentration in cell culture medium, produced from in UHV-alginate incorporated fibroblasts and released out of the alginate matrix into the medium, was significantly increased after 30 days of cultivation. Supernatant of 7 days incubated UHV-alginate containing NIH3T3/BDNF cells significantly increased the SGC survival in vitro. CONCLUSION This study demonstrates UHV-alginate to be a suitable scaffold for BDNF-producing fibroblasts. UHV-alginates are a promising biomaterial for cochlear implant biofunctionalization.
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Affiliation(s)
- Mareike Hütten
- Department of Otolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany
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Liu H, Feng L, Tolia G, Liddell MR, Hao J, Li SK. Evaluation of intratympanic formulations for inner ear delivery: methodology and sustained release formulation testing. Drug Dev Ind Pharm 2013; 40:896-903. [PMID: 23631539 DOI: 10.3109/03639045.2013.789054] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A convenient and efficient in vitro diffusion cell method to evaluate formulations for inner ear delivery via the intratympanic route is currently not available. The existing in vitro diffusion cell systems commonly used to evaluate drug formulations do not resemble the physical dimensions of the middle ear and round window membrane. The objectives of this study were to examine a modified in vitro diffusion cell system of a small diffusion area for studying sustained release formulations in inner ear drug delivery and to identify a formulation for sustained drug delivery to the inner ear. Four formulations and a control were examined in this study using cidofovir as the model drug. Drug release from the formulations in the modified diffusion cell system was slower than that in the conventional diffusion cell system due to the decrease in the diffusion surface area of the modified diffusion cell system. The modified diffusion cell system was able to show different drug release behaviors among the formulations and allowed formulation evaluation better than the conventional diffusion cell system. Among the formulations investigated, poly(lactic-co-glycolic acid)-poly(ethylene glycol)-poly(lactic-co-glycolic acid) triblock copolymer systems provided the longest sustained drug delivery, probably due to their rigid gel structures and/or polymer-to-cidofovir interactions.
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Affiliation(s)
- Hongzhuo Liu
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati , Cincinnati, OH , USA
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Eshraghi AA, Nazarian R, Telischi FF, Rajguru SM, Truy E, Gupta C. The cochlear implant: historical aspects and future prospects. Anat Rec (Hoboken) 2012; 295:1967-80. [PMID: 23044644 DOI: 10.1002/ar.22580] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 07/24/2012] [Indexed: 02/06/2023]
Abstract
The cochlear implant (CI) is the first effective treatment for deafness and severe losses in hearing. As such, the CI is now widely regarded as one of the great advances in modern medicine. This article reviews the key events and discoveries that led up to the current CI systems, and we review and present some among the many possibilities for further improvements in device design and performance. The past achievements include: (1) development of reliable devices that can be used over the lifetime of a patient; (2) development of arrays of implanted electrodes that can stimulate more than one site in the cochlea; and (3) progressive and large improvements in sound processing strategies for CIs. In addition, cooperation between research organizations and companies greatly accelerated the widespread availability and use of safe and effective devices. Possibilities for the future include: (1) use of otoprotective drugs; (2) further improvements in electrode designs and placements; (3) further improvements in sound processing strategies; (4) use of stem cells to replace lost sensory hair cells and neural structures in the cochlea; (5) gene therapy; (6) further reductions in the trauma caused by insertions of electrodes and other manipulations during implant surgeries; and (7) optical rather electrical stimulation of the auditory nerve. Each of these possibilities is the subject of active research. Although great progress has been made to date in the development of the CI, including the first substantial restoration of a human sense, much more progress seems likely and certainly would not be a surprise.
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Affiliation(s)
- Adrien A Eshraghi
- Department of Otolaryngology, University of Miami Ear Institute, University of Miami Miller School of Medicine, Miami, Florida 33136-1015, USA.
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