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Reynisson H, Nivison-Smith L, Lovell NH, Kalloniatis M, Shivdasani MN. Development of a rabbit model of Adenosine triphosphate-induced monocular retinal degeneration for optimization of retinal prostheses. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083330 DOI: 10.1109/embc40787.2023.10340920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Optimization of retinal prostheses requires preclinical animal models that mimic features of human retinal disease, have appropriate eye sizes to accommodate implantable arrays, and provide options for unilateral degeneration so as to enable a contralateral, within-animal control eye. In absence of a suitable non-human primate model and shortcomings of our previous feline model generated through intravitreal injections of Adenosine Triphosphate (ATP), we aimed in the present study to develop an ATP induced degeneration model in the rabbit. Six normally sighted Dutch rabbits were monocularly blinded with this technique. Subsequent retinal degeneration was assessed with optical coherence tomography, electroretinography, and histological assays. Overall, there was a 42% and 26% reduction in a-wave and oscillatory potential amplitudes in the electroretinograms respectively, along with a global decrease in retinal thickness, with increased variability. Qualitative inspection also revealed that there were variable levels of retinal degeneration and remodeling both within and between treated eyes, mimicking the disease heterogeneity observed in retinitis pigmentosa. These findings confirm that ATP can be utilized to unilaterally induce blinding in rabbits and, potentially present an ideal model for future cortical recording experiments aimed at optimizing vision restoration strategies.Clinical Relevance- A rapid, unilaterally induced model of retinal degeneration in an animal with low binocular overlap and large eyes will allow for clinically valid recordings of downstream cortical activity following retinal stimulation. Such a model would be highly beneficial for the optimization of clinically appropriate vision restoration approaches.
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Karamali F, Behtaj S, Babaei-Abraki S, Hadady H, Atefi A, Savoj S, Soroushzadeh S, Najafian S, Nasr Esfahani MH, Klassen H. Potential therapeutic strategies for photoreceptor degeneration: the path to restore vision. J Transl Med 2022; 20:572. [PMID: 36476500 PMCID: PMC9727916 DOI: 10.1186/s12967-022-03738-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/29/2022] [Indexed: 12/12/2022] Open
Abstract
Photoreceptors (PRs), as the most abundant and light-sensing cells of the neuroretina, are responsible for converting light into electrical signals that can be interpreted by the brain. PR degeneration, including morphological and functional impairment of these cells, causes significant diminution of the retina's ability to detect light, with consequent loss of vision. Recent findings in ocular regenerative medicine have opened promising avenues to apply neuroprotective therapy, gene therapy, cell replacement therapy, and visual prostheses to the challenge of restoring vision. However, successful visual restoration in the clinical setting requires application of these therapeutic approaches at the appropriate stage of the retinal degeneration. In this review, firstly, we discuss the mechanisms of PR degeneration by focusing on the molecular mechanisms underlying cell death. Subsequently, innovations, recent developments, and promising treatments based on the stage of disorder progression are further explored. Then, the challenges to be addressed before implementation of these therapies in clinical practice are considered. Finally, potential solutions to overcome the current limitations of this growing research area are suggested. Overall, the majority of current treatment modalities are still at an early stage of development and require extensive additional studies, both pre-clinical and clinical, before full restoration of visual function in PR degeneration diseases can be realized.
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Affiliation(s)
- Fereshteh Karamali
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sanaz Behtaj
- grid.1022.10000 0004 0437 5432Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Queensland, Australia ,grid.1022.10000 0004 0437 5432Menzies Health Institute Queensland, Griffith University, Southport, QLD 4222 Australia
| | - Shahnaz Babaei-Abraki
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Hanieh Hadady
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Atefeh Atefi
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Soraya Savoj
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sareh Soroushzadeh
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Samaneh Najafian
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Mohammad Hossein Nasr Esfahani
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Henry Klassen
- grid.266093.80000 0001 0668 7243Gavin Herbert Eye Institute, Irvine, CA USA
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Cho BJ, Seo JM, Yu HG, Chung H. Monocular retinal degeneration induced by intravitreal injection of sodium iodate in rabbit eyes. Jpn J Ophthalmol 2016; 60:226-37. [PMID: 26902976 DOI: 10.1007/s10384-016-0429-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/22/2015] [Indexed: 01/10/2023]
Abstract
PURPOSE Our purpose was to evaluate the anatomical and functional changes in retinae of rabbit eyes following monocular intravitreal injection of sodium iodate (SI). METHODS Twenty albino rabbits were divided into four groups and underwent monocular intravitreal injection with four different doses of SI (0.1, 0.2, 0.4, and 0.8 mg). Before and for 28 days after injection, the eyes were examined using fundus photography, optical coherence tomography (OCT), and electroretinography (ERG). At postinjection days 2, 7, and 28, the eyes were enucleated and underwent histological examination. RESULTS On fundus examination, no distinct retinal changes were seen in any group except the 0.8-mg group, which showed chorioretinal vascular attenuation. In 0.1 and 0.2-mg groups, no significant anatomical changes were found except transient hyperreflective dots over the vitreoretinal interface on OCT. In 0.4 and 0.8-mg groups, disruption of the ellipsoid zone and diffuse retinal swelling were observed in the early period on OCT. In the 0.4-mg group, the outer retina was significantly destroyed at day 28, whereas the inner retina was relatively preserved. In the 0.8-mg group, the entire retina was destroyed irreversibly. The b-wave of ERG was reduced immediately in all groups, which recovered fully (0.1- and 0.2-mg groups), partially (0.4-mg group), or never (0.8-mg group). No structural or functional abnormalities were found in the fellow control eyes. CONCLUSIONS Retinal degeneration following intravitreal injection of SI appears to be dose dependent; retinal damage is reversible at low doses but irreversible at high doses. At a certain dose, the outer retina may be preferably ablated.
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Affiliation(s)
- Bum-Joo Cho
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.,Seoul Artificial Eye Center, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,Department of Ophthalmology, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Gangwon-do, Korea
| | - Jong-Mo Seo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.,Seoul Artificial Eye Center, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
| | - Hyeong Gon Yu
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.,Seoul Artificial Eye Center, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Hum Chung
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea. .,Seoul Artificial Eye Center, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea. .,Department of Ophthalmology, Chung-Ang University Hospital, Seoul, Korea.
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Zapf MPH, Boon MY, Matteucci PB, Lovell NH, Suaning GJ. Towards an assistive peripheral visual prosthesis for long-term treatment of retinitis pigmentosa: evaluating mobility performance in immersive simulations. J Neural Eng 2015; 12:036001. [DOI: 10.1088/1741-2560/12/3/036001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Stronks HC, Barry MP, Dagnelie G. Electrically elicited visual evoked potentials in Argus II retinal implant wearers. Invest Ophthalmol Vis Sci 2013; 54:3891-901. [PMID: 23611993 DOI: 10.1167/iovs.13-11594] [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: 11/24/2022] Open
Abstract
PURPOSE We characterized electrically elicited visual evoked potentials (eVEPs) in Argus II retinal implant wearers. METHODS eVEPs were recorded in four subjects, and analyzed by determining amplitude and latency of the first two positive peaks (P1 and P2). Subjects provided subjective feedback by rating the brightness and size of the phosphenes. We established eVEP input-output relationships, eVEP variability between and within subjects, the effect of stimulating different areas of the retina, and the maximal pulse rate to record eVEPs reliably. RESULTS eVEP waveforms had low signal-to-noise ratios, requiring long recording times and substantial signal processing. Waveforms varied between subjects, but showed good reproducibility and consistent parameter dependence within subjects. P2 amplitude overall was the most robust outcome measure and proved an accurate indicator of subjective threshold. Peak latencies showed small within-subject variability, yet their correlation with stimulus level and subjective rating were more variable than that of peak amplitudes. Pulse rates of up to (2)/3 Hz resulted in reliable eVEP recordings. Perceived phosphene brightness declined over time, as reflected in P1 amplitude, but not in P2 amplitude or peak latencies. Stimulating-electrode location significantly affected P1 and P2 amplitude and latency, but not subjective percepts. CONCLUSIONS While recording times and signal processing are more demanding than for standard visually evoked potential (VEP) recordings, the eVEP has proven to be a reliable tool to verify retinal implant functionality. eVEPs correlated with various stimulus parameters and with perceptual ratings. In view of these findings, eVEPs may become an important tool in functional investigations of retinal prostheses. (ClinicalTrials.gov number NCT00407602.) Dutch Abstract.
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O'Brien EE, Greferath U, Vessey KA, Jobling AI, Fletcher EL. Electronic restoration of vision in those with photoreceptor degenerations. Clin Exp Optom 2012; 95:473-83. [PMID: 22823954 DOI: 10.1111/j.1444-0938.2012.00783.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 06/06/2012] [Accepted: 06/11/2012] [Indexed: 11/27/2022] Open
Abstract
Complete loss of vision is one of the most feared sequelae of retinal disease. Currently, there are few if any treatment options available to patients that may slow or prevent blindness in diseases caused by photoreceptor loss, such as retinitis pigmentosa and age-related macular degeneration. Electronic restoration of vision has emerged over recent years as a safe and viable option for those who have lost substantial numbers of photoreceptors and who are severely vision impaired. Indeed, there has been a dramatic increase in our understanding of what is required to restore vision using an electronic retinal prosthesis. Recent reports show that for some patients, restoration of vision to the point of reading large letters is possible. In this review, we examine the types of implants currently under investigation and the results these devices have achieved clinically. We then consider a range of engineering and biological factors that may need to be considered to improve the visual performance of newer-generation devices. With added research, it is hoped that the level of vision achieved with newer generation devices will steadily improve, resulting in enhanced quality of life for those with severe vision impairment.
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Affiliation(s)
- Emily E O'Brien
- Department of Anatomy and Cell Biology, The University of Melbourne, Parkville, Victoria, Australia.
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Joarder SA, Abramian M, Suaning GJ, Lovell NH, Dokos S. A continuum model of retinal electrical stimulation. J Neural Eng 2011; 8:066006. [PMID: 22027346 DOI: 10.1088/1741-2560/8/6/066006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ng DC, Bai S, Yang J, Tran N, Skafidas E. Wireless technologies for closed-loop retinal prostheses. J Neural Eng 2009; 6:065004. [DOI: 10.1088/1741-2560/6/6/065004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Dowling J. Current and future prospects for optoelectronic retinal prostheses. Eye (Lond) 2008; 23:1999-2005. [PMID: 19098703 DOI: 10.1038/eye.2008.385] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
There has been accelerating progress in the development of retinal prosthesis systems designed to partially restore vision to people with retinitis pigmentosa or macular degeneration. Current retinal prostheses can be divided into two types: those that receive power and information from passive or active photodiodes (optoelectronic systems) and those based on multielectrode arrays powered by cables or transcutaneous telemetry systems. Currently, four research groups have ongoing chronic implantation clinical studies, and two of these groups plan to have commercial retinal prosthesis systems available within the next 2 years. This paper reviews the development and current status of the most significant international retinal prosthesis research groups and discusses future prospects and issues associated with their retinal prosthesis systems.
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Affiliation(s)
- J Dowling
- CSIRO ICT Centre, The Australian e-Health Research Centre - BioMedIA, Level 7, UQ CCR Building 71/918, Royal Brisbane and Women's Hospital, Herston, Queensland QLD 4029, Australia.
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A review of in vivo animal studies in retinal prosthesis research. Graefes Arch Clin Exp Ophthalmol 2008; 246:1505-17. [PMID: 18709385 DOI: 10.1007/s00417-008-0891-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2008] [Revised: 06/12/2008] [Accepted: 06/16/2008] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The development of a functional retinal prosthesis for acquired blindness is a great challenge. Rapid progress in the field over the last 15 years would not have been possible without extensive animal experimentation pertaining to device design and fabrication, biocompatibility, stimulation parameters and functional responses. This paper presents an overview of in vivo animal research related to retinal prosthetics, and aims to summarize the relevant studies. METHODS A Pubmed search of the English language literature was performed. The key search terms were: retinal implant, retinal prosthesis, artificial vision, rat, rabbit, cat, dog, sheep, pig, minipig. In addition a manual search was performed based on references quoted in the articles retrieved through Pubmed. RESULTS We identified 50 articles relevant to in vivo animal experimentation directly related to the development of a retinal implant. The highest number of publications related to the cat (n = 18). CONCLUSION The contribution of animal models to the development of retinal prosthetic devices has been enormous, and has led to human feasibility studies. Grey areas remain regarding long-term tissue-implant interactions, biomaterials, prosthesis design and neural adaptation. Animals will continue to play a key role in this rapidly evolving field.
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