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McCall MA. Pig Models in Retinal Research and Retinal Disease. Cold Spring Harb Perspect Med 2024; 14:a041296. [PMID: 37553210 PMCID: PMC10982707 DOI: 10.1101/cshperspect.a041296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
The pig has been used as a large animal model in biomedical research for many years and its use continues to increase because induced mutations phenocopy several inherited human diseases. In addition, they are continuous breeders, can be propagated by artificial insemination, have large litter sizes (on the order of mice), and can be genetically manipulated using all of the techniques that are currently available in mice. The pioneering work of Petters and colleagues set the stage for the use of the pig as a model of inherited retinal disease. In the last 10 years, the pig has become a model of choice where specific disease-causing mutations that are not phenocopied in rodents need to be studied and therapeutic approaches explored. The pig is not only used for retinal eye disease but also for the study of the cornea and lens. This review attempts to show how broad the use of the pig has become and how it has contributed to the assessment of treatments for eye disease. In the last 10 years, there have been several reviews that included the use of the pig in biomedical research (see body of the review) that included information about retinal disease. None directly discuss the use of the pig as an animal model for retinal diseases, including inherited diseases, where a single genetic mutation has been identified or for multifactorial diseases such as glaucoma and diabetic retinopathy. Although the pig is used to explore diseases of the cornea and lens, this review focuses on how and why the pig, as a large animal model, is useful for research in neural retinal disease and its treatment.
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Affiliation(s)
- Maureen A McCall
- Departments of Ophthalmology & Visual Sciences and Anatomical Sciences & Neurobiology, University of Louisville, Louisville, Kentucky 40202, USA
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Vu QA, Seo HW, Choi KE, Kim N, Kang YN, Lee J, Park SH, Kim JT, Kim S, Kim SW. Structural changes in the retina after implantation of subretinal three-dimensional implants in mini pigs. Front Neurosci 2022; 16:1010445. [PMID: 36248640 PMCID: PMC9561346 DOI: 10.3389/fnins.2022.1010445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/16/2022] [Indexed: 11/30/2022] Open
Abstract
The retinal structural changes after subretinal implantation of three-dimensional (3D) microelectrodes were investigated in a mini pig. Three types of electrode were implanted into the subretinal spaces of nine mini pigs: 75-μm-high 3D electrodes on a 200-μm-thick right-angled polydimethylsiloxane (PDMS) substrate (group 1); a 140-μm-thick sloped PDMS substrate without electrodes (group 2); and a 140-μm-thick sloped PDMS substrate with 20-μm-high 3D electrodes (group 3). One mini pig was used as a control. Spectral domain–optical coherence tomography (SD–OCT) images were obtained at baseline and 2, 6, and 12 weeks post-surgery. Retinal specimens were immunostained using a tissue-clearing method 3 months post-implantation. The 75-μm-high 3D electrodes progressively penetrated the inner nuclear layer (INL) and touched the inner plexiform layer (IPL) 2 weeks post-surgery. At 6 weeks post-operatively, the electrodes were in contact with the nerve-fiber layer, accompanied by a severe fibrous reaction. In the other groups, the implants remained in place without subretinal migration. Immunostaining showed that retinal ganglion and bipolar cells were preserved without fibrosis over the retinal implants in groups 2 and 3 during the 12-week implantation period. In summary, SD–OCT and immunohistology results showed differences in the extent of reactions, such as fibrosis over the implants and penetration of the electrodes into the inner retinal layer depending on different types of electrodes. A sloped substrate performed better than a right-angled substrate in terms of retinal preservation over the implanted electrodes. The 20-μm-high electrodes showed better structural compatibility than the 75-μm-high 3D electrodes. There was no significant difference between the results of sloped implants without electrodes and 20-μm-high 3D electrodes, indicating that the latter had no adverse effects on retinal tissue.
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Affiliation(s)
- Que Anh Vu
- Department of Ophthalmology, Korea University School of Medicine, Seoul, South Korea
- Department of Ophthalmology, Hanoi Medical University, Hanoi, Vietnam
| | - Hee Won Seo
- Department of Robotics and Mechatronics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Kwang-Eon Choi
- Department of Ophthalmology, Korea University School of Medicine, Seoul, South Korea
| | - Namju Kim
- Department of Robotics and Mechatronics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Yoo Na Kang
- Department of Medical Assistant Robot, Korea Institute of Machinery and Materials (KIMM), Daegu, South Korea
| | - Jaemeun Lee
- R&D Center for Advanced Pharmaceuticals and Evaluation, Korea Institute of Toxicology, Daejeon, South Korea
| | - Sun-Hyun Park
- R&D Center for Advanced Pharmaceuticals and Evaluation, Korea Institute of Toxicology, Daejeon, South Korea
| | - Jee Taek Kim
- Department of Ophthalmology, Chung-Ang University College of Medicine, Seoul, South Korea
| | - Sohee Kim
- Department of Robotics and Mechatronics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
- *Correspondence: Sohee Kim,
| | - Seong-Woo Kim
- Department of Ophthalmology, Korea University School of Medicine, Seoul, South Korea
- Seong-Woo Kim,
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Choi KE, Anh VTQ, Seo HW, Kim N, Kim S, Kim SW. Ab-interno surgical technique for the implantation of a wireless subretinal prosthesis in mini-pigs. Sci Rep 2020; 10:18507. [PMID: 33116246 PMCID: PMC7595207 DOI: 10.1038/s41598-020-75579-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 10/16/2020] [Indexed: 11/22/2022] Open
Abstract
We sought to describe the surgical techniques required in the ab-interno method to implant subretinal prostheses in mini-pigs and suggest tips to facilitate optimal outcomes. During vitrectomy, the use of valved trocar cannulas was essential to stabilize the detached retina and implanted chip. As a first step in retinal detachment, a 23-gauge cannula with very small amount of viscoelastic material was used to establish the retinal hole and promote retinal detachment. Then, balanced salt solution was applied to increase the retinal detachment and diathermy was used to make opening for subretinal prosthesis. For easy positioning of the subretinal prosthesis, a curved laser probe was adopted when handling the subretinal prosthesis under the retina. After surgery, the sclerotomy sites were tightly sutured to prevent silicone oil leakage. Without special equipment, such as a 41-gauge tip, retinal detachment could be induced easily, while the prosthesis was also successfully inserted and manipulated under the retina without an iatrogenic retinal tear. Two weeks after the operation, the oil fully occupied the intraocular volume without leakage. The subretinal prosthesis remained stable without complication. Understanding the principle of the ab-interno method and considering several tips for improving surgical access may help to enhance surgical success rates of subretinal prostheses implantation.
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Affiliation(s)
- Kwang-Eon Choi
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Vu Thi Que Anh
- Department of Ophthalmology, Hanoi Medical University, Hanoi, Vietnam
| | - Hee Won Seo
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Namju Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Sohee Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea.
| | - Seong-Woo Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
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Allen RS, Bales K, Feola A, Pardue MT. In vivo Structural Assessments of Ocular Disease in Rodent Models using Optical Coherence Tomography. J Vis Exp 2020. [PMID: 32773758 DOI: 10.3791/61588] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Spectral-domain optical coherence tomography (SD-OCT) is useful for visualizing retinal and ocular structures in vivo. In research, SD-OCT is a valuable tool to evaluate and characterize changes in a variety of retinal and ocular disease and injury models. In light induced retinal degeneration models, SD-OCT can be used to track thinning of the photoreceptor layer over time. In glaucoma models, SD-OCT can be used to monitor decreased retinal nerve fiber layer and total retinal thickness and to observe optic nerve cupping after inducing ocular hypertension. In diabetic rodents, SD-OCT has helped researchers observe decreased total retinal thickness as well as decreased thickness of specific retinal layers, particularly the retinal nerve fiber layer with disease progression. In mouse models of myopia, SD-OCT can be used to evaluate axial parameters, such as axial length changes. Advantages of SD-OCT include in vivo imaging of ocular structures, the ability to quantitatively track changes in ocular dimensions over time, and its rapid scanning speed and high resolution. Here, we detail the methods of SD-OCT and show examples of its use in our laboratory in models of retinal degeneration, glaucoma, diabetic retinopathy, and myopia. Methods include anesthesia, SD-OCT imaging, and processing of the images for thickness measurements.
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Affiliation(s)
- Rachael S Allen
- Center of Excellence for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center; Department of Biomedical Engineering, Georgia Institute of Technology;
| | - Katie Bales
- Center of Excellence for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center; Department of Ophthalmology, Emory University
| | - Andrew Feola
- Center of Excellence for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center; Department of Biomedical Engineering, Georgia Institute of Technology
| | - Machelle T Pardue
- Center of Excellence for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center; Department of Biomedical Engineering, Georgia Institute of Technology; Department of Ophthalmology, Emory University
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PRIMA subretinal wireless photovoltaic microchip implantation in non-human primate and feline models. PLoS One 2020; 15:e0230713. [PMID: 32267845 PMCID: PMC7141693 DOI: 10.1371/journal.pone.0230713] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 03/05/2020] [Indexed: 12/05/2022] Open
Abstract
Purpose To evaluate the surgical technique for subretinal implantation of two sizes of PRIMA photovoltaic wireless microchip in two animal models, and refine these surgical procedures for human trials. Methods Cats and Macaca fascicularis primates with healthy retina underwent vitrectomy surgery and were implanted with subretinal wireless photovoltaic microchip at the macula/central retina. The 1.5mm PRIMA chip was initially studied in feline eyes. PRIMA implant (2mm,1.5mm sizes) arrays were studied in primates. Feasibility of subretinal chip implantation was evaluated with a newly-developed surgical technique, with surgical complications and adverse events recorded. Results The 1.5mm implant was placed in the central retina of 11 feline eyes, with implantation duration 43–106 days. The 1.5mm implant was correctly positioned into central macula of 11 primate eyes, with follow-up periods of minimum 6 weeks (n = 11), 2 years (n = 2), and one eye for 3 years. One primate eye underwent multi-chip 1.5mm implantation using two 1.5mm chips. The 2mm implant was delivered to 4 primate eyes. Optical coherence tomography confirmed correct surgical placement of photovoltaic arrays in the subretinal space in all 26 eyes. Intraoperative complications in primate eyes included retinal tear, macular hole, retinal detachment, and vitreous hemorrhage that resolved spontaneously. Postoperatively, there was no case of significant ocular inflammation in the 1.5mm implant group. Conclusions We report subretinal implantation of 1.5mm and 2mm photovoltaic arrays in the central retina of feline and central macula of primate eyes with a low rate of device-related complications. The in vivo PRIMA implantation technique has been developed and refined for use for a 2mm PRIMA implant in ongoing human trials.
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Huckenpahler AL, Carroll J, Salmon AE, Sajdak BS, Mastey RR, Allen KP, Kaplan HJ, McCall MA. Noninvasive Imaging and Correlative Histology of Cone Photoreceptor Structure in the Pig Retina. Transl Vis Sci Technol 2019; 8:38. [PMID: 31867139 PMCID: PMC6922271 DOI: 10.1167/tvst.8.6.38] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 10/04/2019] [Indexed: 12/16/2022] Open
Abstract
PURPOSE To evaluate different methods of studying cone photoreceptor structure in wild-type (WT) and transgenic pigs carrying the human rhodopsin P23H mutant gene (TgP23H). METHODS For in vivo imaging, pigs were anesthetized with tiletamine-zolazepam and isoflurane and given lidocaine-bupivacaine retrobulbar injections. Stay sutures and a custom head mount were used to hold and steer the head for adaptive optics scanning light ophthalmoscopy (AOSLO). Six WT and TgP23H littermates were imaged at postnatal day 30 (P30), P90, and P180 with AOSLO and optical coherence tomography (OCT), and two additional sets of littermates were imaged at P3 and P15 with OCT only. AOSLO imaging and correlative differential interference contrast microscopy were performed on a P240 WT pig and on WT and TgP23H littermates at P30 and P180. RESULTS AOSLO cone density generally underestimates histology density (mean difference ± SD = 24.8% ± 21.4%). The intensity of the outer retinal hyperreflective OCT band attributed to photoreceptors is attenuated in TgP23H pigs at all ages. In contrast, AOSLO images show cones that retain inner and outer segments through P180. At retinal locations outside the visual streak, TgP23H pigs show a heterogeneous degenerating cone mosaic by using two criteria: variable contrast on a split detector AOSLO and high reflectivity on a confocal AOSLO. CONCLUSIONS AOSLO reveals that the cone mosaic is similar to ex vivo histology. Its use as a noninvasive tool will enable observation of morphologic changes that arise in the cone mosaic of TgP23H pigs over time. TRANSLATIONAL RELEVANCE Pigs are widely used for translational studies, and the ability to noninvasively assess cellular changes in the cone mosaic will facilitate more detailed investigations of new retinal disease models as well as outcomes of potential therapies.
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Affiliation(s)
- Alison L Huckenpahler
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joseph Carroll
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Alexander E Salmon
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Benjamin S Sajdak
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Rebecca R Mastey
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Kenneth P Allen
- Biomedical Resource Center, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Henry J Kaplan
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, USA
| | - Maureen A McCall
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, USA
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, USA
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Flores T, Huang T, Bhuckory M, Ho E, Chen Z, Dalal R, Galambos L, Kamins T, Mathieson K, Palanker D. Honeycomb-shaped electro-neural interface enables cellular-scale pixels in subretinal prosthesis. Sci Rep 2019; 9:10657. [PMID: 31337815 PMCID: PMC6650428 DOI: 10.1038/s41598-019-47082-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 07/10/2019] [Indexed: 11/08/2022] Open
Abstract
High-resolution visual prostheses require small, densely packed pixels, but limited penetration depth of the electric field formed by a planar electrode array constrains such miniaturization. We present a novel honeycomb configuration of an electrode array with vertically separated active and return electrodes designed to leverage migration of retinal cells into voids in the subretinal space. Insulating walls surrounding each pixel decouple the field penetration depth from the pixel width by aligning the electric field vertically, enabling a decrease of the pixel size down to cellular dimensions. We demonstrate that inner retinal cells migrate into the 25 μm deep honeycomb wells as narrow as 18 μm, resulting in more than half of these cells residing within the electrode cavities. Immune response to honeycombs is comparable to that with planar arrays. Modeled stimulation threshold current density with honeycombs does not increase substantially with reduced pixel size, unlike quadratic increase with planar arrays. This 3-D electrode configuration may enable functional restoration of central vision with acuity better than 20/100 for millions of patients suffering from age-related macular degeneration.
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Affiliation(s)
- Thomas Flores
- Department of Applied Physics, Stanford University, Stanford, CA, USA.
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA.
| | - Tiffany Huang
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Mohajeet Bhuckory
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Elton Ho
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Physics, Stanford University, Stanford, CA, USA
| | - Zhijie Chen
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Ludwig Galambos
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Theodore Kamins
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Keith Mathieson
- Institute of Photonics, University of Strathclyde, Glasgow, Scotland, UK
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
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Xie W, Zhao M, Tsai SH, Burkes WL, Potts LB, Xu W, Payne HR, Hein TW, Kuo L, Rosa RH. Correlation of spectral domain optical coherence tomography with histology and electron microscopy in the porcine retina. Exp Eye Res 2018; 177:181-190. [PMID: 30120928 DOI: 10.1016/j.exer.2018.08.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 08/03/2018] [Accepted: 08/06/2018] [Indexed: 02/07/2023]
Abstract
Spectral domain optical coherence tomography (SD-OCT) is used as a non-invasive tool for retinal morphological assessment in vivo. Information on the correlation of SD-OCT with retinal histology in the porcine retina, a model resembling the human retina, is limited. Herein, we correlated the hypo- and hyper-reflective bands on SD-OCT with histology of the lamellar architecture and cellular constituents of the porcine retina. SD-OCT images were acquired with the Heidelberg Spectralis HRA + OCT. Histological analysis was performed using epoxy resin embedded tissue and transmission electron microscopy. Photomicrographs from the histologic sections were linearly scaled to correct for tissue shrinkage and correlated with SD-OCT images. SD-OCT images correlated well with histomorphometric data. A hyper-reflective band in the mid-to-outer inner nuclear layer correlated with the presence of abundant mitochondria in horizontal cell processes and adjacent bipolar cells. A concentration of cone nuclei corresponded to a relative hypo-reflective band in the outer portion of the outer nuclear layer. The presence of 3 hyper-reflective bands in the outer retina corresponded to: 1) the external limiting membrane; 2) the cone and rod ellipsoid zones; and 3) the interdigitation zone of photoreceptor outer segments/retinal pigment epithelium (RPE) apical cell processes and the RPE. These correlative and normative SD-OCT data may be employed to characterize and assess the in vivo histologic changes in retinal vascular and degenerative diseases and the responses to novel therapeutic interventions in this large animal model.
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Affiliation(s)
- Wankun Xie
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX, USA; Department of Ophthalmology and Ophthalmic Vascular Research Program, Scott & White Eye Institute, Temple, TX, USA
| | - Min Zhao
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX, USA; Department of Ophthalmology and Ophthalmic Vascular Research Program, Scott & White Eye Institute, Temple, TX, USA
| | - Shu-Huai Tsai
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX, USA
| | - William L Burkes
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX, USA
| | - Luke B Potts
- Department of Ophthalmology and Ophthalmic Vascular Research Program, Scott & White Eye Institute, Temple, TX, USA
| | - Wenjuan Xu
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX, USA
| | - H Ross Payne
- Image Analysis Laboratory, Texas A&M University College of Veterinary Medicine, College Station, TX, USA
| | - Travis W Hein
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX, USA; Department of Ophthalmology and Ophthalmic Vascular Research Program, Scott & White Eye Institute, Temple, TX, USA
| | - Lih Kuo
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX, USA; Department of Ophthalmology and Ophthalmic Vascular Research Program, Scott & White Eye Institute, Temple, TX, USA
| | - Robert H Rosa
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX, USA; Department of Ophthalmology and Ophthalmic Vascular Research Program, Scott & White Eye Institute, Temple, TX, USA.
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LaVail MM, Nishikawa S, Steinberg RH, Naash MI, Duncan JL, Trautmann N, Matthes MT, Yasumura D, Lau-Villacorta C, Chen J, Peterson WM, Yang H, Flannery JG. Phenotypic characterization of P23H and S334ter rhodopsin transgenic rat models of inherited retinal degeneration. Exp Eye Res 2018; 167:56-90. [PMID: 29122605 PMCID: PMC5811379 DOI: 10.1016/j.exer.2017.10.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/25/2017] [Accepted: 10/31/2017] [Indexed: 02/07/2023]
Abstract
We produced 8 lines of transgenic (Tg) rats expressing one of two different rhodopsin mutations in albino Sprague-Dawley (SD) rats. Three lines were generated with a proline to histidine substitution at codon 23 (P23H), the most common autosomal dominant form of retinitis pigmentosa in the United States. Five lines were generated with a termination codon at position 334 (S334ter), resulting in a C-terminal truncated opsin protein lacking the last 15 amino acid residues and containing all of the phosphorylation sites involved in rhodopsin deactivation, as well as the terminal QVAPA residues important for rhodopsin deactivation and trafficking. The rates of photoreceptor (PR) degeneration in these models vary in proportion to the ratio of mutant to wild-type rhodopsin. The models have been widely studied, but many aspects of their phenotypes have not been described. Here we present a comprehensive study of the 8 Tg lines, including the time course of PR degeneration from the onset to one year of age, retinal structure by light and electron microscopy (EM), hemispheric asymmetry and gradients of rod and cone degeneration, rhodopsin content, gene dosage effect, rapid activation and invasion of the outer retina by presumptive microglia, rod outer segment disc shedding and phagocytosis by the retinal pigmented epithelium (RPE), and retinal function by the electroretinogram (ERG). The biphasic nature of PR cell death was noted, as was the lack of an injury-induced protective response in the rat models. EM analysis revealed the accumulation of submicron vesicular structures in the interphotoreceptor space during the peak period of PR outer segment degeneration in the S334ter lines. This is likely due to the elimination of the trafficking consensus domain as seen before as with other rhodopsin mutants lacking the C-terminal QVAPA. The 8 rhodopsin Tg lines have been, and will continue to be, extremely useful models for the experimental study of inherited retinal degenerations.
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Affiliation(s)
- Matthew M LaVail
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Shimpei Nishikawa
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Roy H Steinberg
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd., Room 2011, Houston, TX 77204-5060, USA.
| | - Jacque L Duncan
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Nikolaus Trautmann
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Michael T Matthes
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Douglas Yasumura
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Cathy Lau-Villacorta
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Jeannie Chen
- Zilka Neurogenetic Institute, USC Keck School of Medicine, Los Angeles, CA 90089-2821, USA.
| | - Ward M Peterson
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Haidong Yang
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - John G Flannery
- School of Optometry, UC Berkeley, Berkeley, CA 94720-2020, USA.
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Antognazza MR, Di Paolo M, Ghezzi D, Mete M, Di Marco S, Maya-Vetencourt JF, Maccarone R, Desii A, Di Fonzo F, Bramini M, Russo A, Laudato L, Donelli I, Cilli M, Freddi G, Pertile G, Lanzani G, Bisti S, Benfenati F. Characterization of a Polymer-Based, Fully Organic Prosthesis for Implantation into the Subretinal Space of the Rat. Adv Healthc Mater 2016; 5:2271-82. [PMID: 27240295 DOI: 10.1002/adhm.201600318] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 04/19/2016] [Indexed: 01/08/2023]
Abstract
Replacement strategies arise as promising approaches in case of inherited retinal dystrophies leading to blindness. A fully organic retinal prosthesis made of conjugated polymers layered onto a silk fibroin substrate is engineered. First, the biophysical and surface properties are characterized; then, the long-term biocompatibility is assessed after implantation of the organic device in the subretinal space of 3-months-old rats for a period of five months. The results indicate a good stability of the subretinal implants over time, with preservation of the physical properties of the polymeric layer and a tight contact with the outer retina. Immunoinflammatory markers detect only a modest tissue reaction to the surgical insult and the foreign body that peaks shortly after surgery and progressively decreases with time to normal levels at five months after implantation. Importantly, the integrity of the polymeric layer in direct contact with the retinal tissue is preserved after five months of implantation. The recovery of the foreign-body tissue reaction is also associated with a normal b-wave in the electroretinographic response. The results demonstrate that the device implanted in nondystrophic eyes is well tolerated, highly biocompatible, and suitable as retinal prosthesis in case of photoreceptor degeneration.
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Affiliation(s)
- Maria Rosa Antognazza
- Center for Nano Science and Technology; Fondazione Istituto Italiano di Tecnologia; Via G. Pascoli 70/3 20133 Milano Italy
| | - Mattia Di Paolo
- Department of Biotechnology and Applied Clinical Science; University of L'Aquila; Via Vetoio, Coppito 2 67100 L'Aquila Italy
| | - Diego Ghezzi
- Center for Synaptic Neuroscience and Technology; Fondazione Istituto Italiano di Tecnologia; Largo Giovanna Benzi 10 16132 Genova Italy
| | - Maurizio Mete
- Unità Operativa di Oculistica, Ospedale Sacro Cuore - Don Calabria; Via don A. Sempreboni 5; 37024 Negrar (Verona) Italy
| | - Stefano Di Marco
- Department of Biotechnology and Applied Clinical Science; University of L'Aquila; Via Vetoio, Coppito 2 67100 L'Aquila Italy
| | - José Fernando Maya-Vetencourt
- Center for Synaptic Neuroscience and Technology; Fondazione Istituto Italiano di Tecnologia; Largo Giovanna Benzi 10 16132 Genova Italy
| | - Rita Maccarone
- Department of Biotechnology and Applied Clinical Science; University of L'Aquila; Via Vetoio, Coppito 2 67100 L'Aquila Italy
| | - Andrea Desii
- Center for Nano Science and Technology; Fondazione Istituto Italiano di Tecnologia; Via G. Pascoli 70/3 20133 Milano Italy
| | - Fabio Di Fonzo
- Center for Nano Science and Technology; Fondazione Istituto Italiano di Tecnologia; Via G. Pascoli 70/3 20133 Milano Italy
| | - Mattia Bramini
- Center for Synaptic Neuroscience and Technology; Fondazione Istituto Italiano di Tecnologia; Largo Giovanna Benzi 10 16132 Genova Italy
| | - Angela Russo
- Unità Operativa di Oculistica, Ospedale Sacro Cuore - Don Calabria; Via don A. Sempreboni 5; 37024 Negrar (Verona) Italy
| | - Lucia Laudato
- Center for Nano Science and Technology; Fondazione Istituto Italiano di Tecnologia; Via G. Pascoli 70/3 20133 Milano Italy
| | - Ilaria Donelli
- Innovhub-SSI; Silk Division; Via Giuseppe Colombo 83 20133 Milano Italy
| | - Michele Cilli
- Animal Facility; IRCCS Azienda Ospedaliera Universitaria San Martino IST Istituto Nazionale per la Ricerca sul Cancro; Largo Giovanna Benzi 10 16132 Genova Italy
| | - Giuliano Freddi
- Innovhub-SSI; Silk Division; Via Giuseppe Colombo 83 20133 Milano Italy
| | - Grazia Pertile
- Unità Operativa di Oculistica, Ospedale Sacro Cuore - Don Calabria; Via don A. Sempreboni 5; 37024 Negrar (Verona) Italy
| | - Guglielmo Lanzani
- Center for Nano Science and Technology; Fondazione Istituto Italiano di Tecnologia; Via G. Pascoli 70/3 20133 Milano Italy
| | - Silvia Bisti
- Department of Biotechnology and Applied Clinical Science; University of L'Aquila; Via Vetoio, Coppito 2 67100 L'Aquila Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology; Fondazione Istituto Italiano di Tecnologia; Largo Giovanna Benzi 10 16132 Genova Italy
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Goetz GA, Palanker DV. Electronic approaches to restoration of sight. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:096701. [PMID: 27502748 PMCID: PMC5031080 DOI: 10.1088/0034-4885/79/9/096701] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Retinal prostheses are a promising means for restoring sight to patients blinded by the gradual atrophy of photoreceptors due to retinal degeneration. They are designed to reintroduce information into the visual system by electrically stimulating surviving neurons in the retina. This review outlines the concepts and technologies behind two major approaches to retinal prosthetics: epiretinal and subretinal. We describe how the visual system responds to electrical stimulation. We highlight major differences between direct encoding of the retinal output with epiretinal stimulation, and network-mediated response with subretinal stimulation. We summarize results of pre-clinical evaluation of prosthetic visual functions in- and ex vivo, as well as the outcomes of current clinical trials of various retinal implants. We also briefly review alternative, non-electronic, approaches to restoration of sight to the blind, and conclude by suggesting some perspectives for future advancement in the field.
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Affiliation(s)
- G A Goetz
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA. Neurosurgery, Stanford University, Stanford, CA 94305, USA
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Jones PD, Stelzle M. Can Nanofluidic Chemical Release Enable Fast, High Resolution Neurotransmitter-Based Neurostimulation? Front Neurosci 2016; 10:138. [PMID: 27065794 PMCID: PMC4815362 DOI: 10.3389/fnins.2016.00138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 03/18/2016] [Indexed: 11/13/2022] Open
Abstract
Artificial chemical stimulation could provide improvements over electrical neurostimulation. Physiological neurotransmission between neurons relies on the nanoscale release and propagation of specific chemical signals to spatially-localized receptors. Current knowledge of nanoscale fluid dynamics and nanofluidic technology allows us to envision artificial mechanisms to achieve fast, high resolution neurotransmitter release. Substantial technological development is required to reach this goal. Nanofluidic technology—rather than microfluidic—will be necessary; this should come as no surprise given the nanofluidic nature of neurotransmission. This perspective reviews the state of the art of high resolution electrical neuroprostheses and their anticipated limitations. Chemical release rates from nanopores are compared to rates achieved at synapses and with iontophoresis. A review of microfluidic technology justifies the analysis that microfluidic control of chemical release would be insufficient. Novel nanofluidic mechanisms are discussed, and we propose that hydrophobic gating may allow control of chemical release suitable for mimicking neurotransmission. The limited understanding of hydrophobic gating in artificial nanopores and the challenges of fabrication and large-scale integration of nanofluidic components are emphasized. Development of suitable nanofluidic technology will require dedicated, long-term efforts over many years.
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