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Olufsen ME, Hannibal J, Sørensen NB, Christiansen AT, Christensen U, Pertile G, Steel DH, Heegaard S, Kiilgaard JF. Wound Healing in a Porcine Model of Retinal Holes. Invest Ophthalmol Vis Sci 2024; 65:35. [PMID: 39186262 PMCID: PMC11361378 DOI: 10.1167/iovs.65.10.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 07/17/2024] [Indexed: 08/27/2024] Open
Abstract
Purpose To investigate retinal wound healing, we created a new porcine model of retinal hole and identified the cells involved in hole closure. Methods Sixteen landrace pigs underwent vitrectomy, and a subretinal bleb was created before cutting a retinal hole using a 23G vitrector. No tamponade was used. Before surgery and one, two, and four weeks after surgery, the eyes were examined by optical coherence tomography and color fundus photos. At the end of follow-up, the eyes were enucleated for histology. Tissue sections of 5 µm were prepared for hematoxylin-eosin staining and immunohistochemical analysis with antibodies to retinal glial and epithelial cells. Results Retinal holes below 1380 µm in diameter closed spontaneously within four weeks, whereas larger holes remained open. Hole closure was mediated by central movement of the edges of the hole and in most cases the formation of a gliotic plug. Fluorescence microscopy revealed that the plug consisted of cells positive for glial fibrillary acidic protein, indicating the presence of macroglial cell types. Specifically, the plug was positive for S100 calcium-binding protein B, mainly representing astrocytes, while it was negative for anti-glutamine syntethase, representing Müller glia. These findings suggest that astrocytes are the predominating cell type in the plug. Minimal glial reaction was seen in the retinal holes that did not close. Conclusions We present a new porcine model for investigating large retinal holes. The retinal holes closed by approximation of hole edges, and the remnant retinal defect was closed with an astroglial plug.
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Affiliation(s)
- Madeline Evers Olufsen
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jens Hannibal
- Faculty of Health and Medical Sciences, Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Faculty of Health Sciences, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Nina Buus Sørensen
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | | | - Ulrik Christensen
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | | | - David H. Steel
- Bioscience Institute, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Steffen Heegaard
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Pathology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jens Folke Kiilgaard
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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Barathi VA, Katz A, Chaudhary S, Li HL, Tal DM, Marcovich A, Do CW, Karlish SJD. A digoxin derivative that potently reduces intraocular pressure: efficacy and mechanism of action in different animal models. Am J Physiol Cell Physiol 2024; 326:C1505-C1519. [PMID: 38557355 PMCID: PMC11371363 DOI: 10.1152/ajpcell.00617.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/04/2024]
Abstract
Glaucoma is a blinding disease. Reduction of intraocular pressure (IOP) is the mainstay of treatment, but current drugs show side effects or become progressively ineffective, highlighting the need for novel compounds. We have synthesized a family of perhydro-1,4-oxazepine derivatives of digoxin, the selective inhibitor of Na,K-ATPase. The cyclobutyl derivative (DcB) displays strong selectivity for the human α2 isoform and potently reduces IOP in rabbits. These observations appeared consistent with a hypothesis that in ciliary epithelium DcB inhibits the α2 isoform of Na,K-ATPase, which is expressed strongly in nonpigmented cells, reducing aqueous humor (AH) inflow. This paper extends assessment of efficacy and mechanism of action of DcB using an ocular hypertensive nonhuman primate model (OHT-NHP) (Macaca fascicularis). In OHT-NHP, DcB potently lowers IOP, in both acute (24 h) and extended (7-10 days) settings, accompanied by increased aqueous humor flow rate (AFR). By contrast, ocular normotensive animals (ONT-NHP) are poorly responsive to DcB, if at all. The mechanism of action of DcB has been analyzed using isolated porcine ciliary epithelium and perfused enucleated eyes to study AH inflow and AH outflow facility, respectively. 1) DcB significantly stimulates AH inflow although prior addition of 8-Br-cAMP, which raises AH inflow, precludes additional effects of DcB. 2) DcB significantly increases AH outflow facility via the trabecular meshwork (TM). Taken together, the data indicate that the original hypothesis on the mechanism of action must be revised. In the OHT-NHP, and presumably other species, DcB lowers IOP by increasing AH outflow facility rather than by decreasing AH inflow.NEW & NOTEWORTHY When applied topically, a cyclobutyl derivative of digoxin (DcB) potently reduces intraocular pressure in an ocular hypertensive nonhuman primate model (Macaca fascicularis), associated with increased aqueous humor (AH) flow rate (AFR). The mechanism of action of DcB involves increased AH outflow facility as detected in enucleated perfused porcine eyes and, in parallel, increased (AH) inflow as detected in isolated porcine ciliary epithelium. DcB might have potential as a drug for the treatment of open-angle human glaucoma.
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Affiliation(s)
- Veluchamy Amutha Barathi
- Translational Pre-Clinical Model Platform, Singapore Institute of Eye Research (SERI)
- ACP in Ophthalmology & Visual Sciences, DUKE-NUS Graduate Medical School, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Adriana Katz
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shashikant Chaudhary
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
| | - Hoi-Lam Li
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
| | - Daniel M Tal
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Arie Marcovich
- Opthalmology Department, Kaplan Medical Center, Rehovot, Israel
- Hebrew University Medical School, Jerusalem, Israel
| | - Chi-Wai Do
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
- Centre for Eye and Vision Research (CEVR), Hong Kong, People's Republic of China
- Research Institute for Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
| | - Steven J D Karlish
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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3
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Jakobsen TS, Fabian-Jessing BK, Hansen S, Bek T, Askou AL, Corydon TJ. Porcine models of choroidal neovascularization: A systematic review. Exp Eye Res 2023; 234:109590. [PMID: 37474015 DOI: 10.1016/j.exer.2023.109590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/13/2023] [Accepted: 07/16/2023] [Indexed: 07/22/2023]
Abstract
Animal models of choroidal neovascularization (CNV) are extensively used in translational studies of CNV formation and to evaluate angiostatic treatment strategies. However, the current paucity of large animal models compared with rodent models constitutes a knowledge gap regarding the clinical translation of findings. Ocular anatomical and physiological similarities to humans suggest the pig as a relevant model animal. Thus, a systematic survey of porcine CNV models was performed to identify pertinent model parameters and suggest avenues for model standardization and optimization. A systematic search was performed in PubMed and EMBASE on November 28, 2022 for porcine models of CNV. Following inclusion by two investigators, data from the articles were extracted according to a predefined protocol. A total of 14 articles, representing 19 independent porcine CNV models were included. The included models were almost equally divided between laser-induced (53%) and surgically-induced (47%) models. Different specified breeds of domestic pigs (71%) were most commonly used in the studies. All studies used normal animals. Female pigs were reported used in 43% of the studies, while 43% did not report on sex of the animals. Younger pigs were typically used. The surgical models reported consistent CNV induction following mechanical Bruch's membrane rupture. The laser models used variants of the infrared diode laser (40%) or the frequency-doubled Nd:YAG laser (50%). Both lasers enabled successful CNV induction with reported induction rates ranging from 60 to 100%. Collateral damage to the neuroretina was reported for the infrared diode laser. CNV evaluation varied across studies with fluorescein angiography (50%) as the most used in vivo method and retinal sections (71%) as the most used ex vivo method. In interventional studies, quantification of lesions was in general performed between 7 and 14 days. The field of porcine CNV models is relatively small and heterogeneous and almost equally divided between surgically-induced and laser-induced models. Both methods have allowed successful modeling of CNV formation with induction rates comparable to those of non-human primates. However, the field would benefit from standardization of model parameters and reporting. This includes laser parameters and validation of CNV formation as well as methods of CNV evaluation and statistical analysis.
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Affiliation(s)
- Thomas Stax Jakobsen
- Department of Biomedicine, Aarhus University, Høegh-Guldbergs Gade 10, 8000, Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 167, 8200, Aarhus N, Denmark.
| | - Bjørn K Fabian-Jessing
- Department of Biomedicine, Aarhus University, Høegh-Guldbergs Gade 10, 8000, Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 167, 8200, Aarhus N, Denmark.
| | - Silja Hansen
- Department of Biomedicine, Aarhus University, Høegh-Guldbergs Gade 10, 8000, Aarhus C, Denmark.
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 167, 8200, Aarhus N, Denmark.
| | - Anne Louise Askou
- Department of Biomedicine, Aarhus University, Høegh-Guldbergs Gade 10, 8000, Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 167, 8200, Aarhus N, Denmark.
| | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, Høegh-Guldbergs Gade 10, 8000, Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 167, 8200, Aarhus N, Denmark.
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Townes-Anderson E, Halász É, Sugino I, Davidow AL, Frishman LJ, Fritzky L, Yousufzai FAK, Zarbin M. Injury to Cone Synapses by Retinal Detachment: Differences from Rod Synapses and Protection by ROCK Inhibition. Cells 2023; 12:1485. [PMID: 37296606 PMCID: PMC10253016 DOI: 10.3390/cells12111485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
Attachment of a detached retina does not always restore vision to pre-injury levels, even if the attachment is anatomically successful. The problem is due in part to long-term damage to photoreceptor synapses. Previously, we reported on damage to rod synapses and synaptic protection using a Rho kinase (ROCK) inhibitor (AR13503) after retinal detachment (RD). This report documents the effects of detachment, reattachment, and protection by ROCK inhibition on cone synapses. Conventional confocal and stimulated emission depletion (STED) microscopy were used for morphological assessment and electroretinograms for functional analysis of an adult pig model of RD. RDs were examined 2 and 4 h after injury or two days later when spontaneous reattachment had occurred. Cone pedicles respond differently than rod spherules. They lose their synaptic ribbons, reduce invaginations, and change their shape. ROCK inhibition protects against these structural abnormalities whether the inhibitor is applied immediately or 2 h after the RD. Functional restoration of the photopic b-wave, indicating cone-bipolar neurotransmission, is also improved with ROCK inhibition. Successful protection of both rod and cone synapses with AR13503 suggests this drug will (1) be a useful adjunct to subretinal administration of gene or stem cell therapies and (2) improve recovery of the injured retina when treatment is delayed.
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Affiliation(s)
- Ellen Townes-Anderson
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA;
| | - Éva Halász
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA;
| | - Ilene Sugino
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, 90 Bergen Street, Newark, NJ 07103, USA; (I.S.); (M.Z.)
| | - Amy L. Davidow
- Department of Biostatistics, New York University School of Global Public Health, 708 Broadway, New York, NY 10003, USA;
| | - Laura J. Frishman
- Department of Vision Sciences, College of Optometry, University of Houston, Martin Luther King Blvd, Houston, TX 77204, USA;
| | - Luke Fritzky
- Cellular Imaging and Histology Core, Rutgers New Jersey Medical School, 205 South Orange Avenue, Newark, NJ 07103, USA; (L.F.); (F.A.K.Y.)
| | - Fawad A. K. Yousufzai
- Cellular Imaging and Histology Core, Rutgers New Jersey Medical School, 205 South Orange Avenue, Newark, NJ 07103, USA; (L.F.); (F.A.K.Y.)
| | - Marco Zarbin
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, 90 Bergen Street, Newark, NJ 07103, USA; (I.S.); (M.Z.)
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Fehler N, Hessling M. Determination of Correlated Color Temperature in Ex Vivo Porcine Eyes during Intraocular Illumination. J Clin Med 2023; 12:3034. [PMID: 37109369 PMCID: PMC10143230 DOI: 10.3390/jcm12083034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/27/2023] [Accepted: 04/20/2023] [Indexed: 04/29/2023] Open
Abstract
(1) Background: In ophthalmic surgery, white light is mostly applied to illuminate the intraocular space, and ophthalmologists are comfortable working with it. Diaphanoscopic illumination changes the spectral composition of light, resulting in a change in the correlated color temperature (CCT) of the intraocular illumination. This color change makes it difficult for surgeons to recognize the structures in the eye. CCT during intraocular illumination has not yet been measured before, and it is the aim of this study to perform such measurement. (2) Methods: CCT was measured inside ex vivo porcine eyes during diaphanoscopic illumination and endoillumination using a current ophthalmic illumination system with a detection fiber inside the eye. By applying pressure on the eye with a diaphanoscopic fiber, the dependency of CCT on pressure was examined. (3) Results: The intraocular CCT values during endoillumination were 3923 K and 5407 K for the halogen and xenon lamps, respectively. During diaphanoscopic illumination, a strong unwanted red shift was observed, resulting in 2199 K and 2675 K for the xenon and the halogen lamps, respectively. Regarding different applied pressures, the CCT did not differ considerably. (4) Conclusions: This red shift should be compensated for in the development of new illumination systems since surgeons are used to white light illumination, which also simplifies the identification of retinal structures.
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Affiliation(s)
- Nicole Fehler
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081 Ulm, Germany
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6
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Li KL, Shan SW, Lin FY, Ling CY, Wong NW, Li HL, Han W, To CH, Do CW. Regulation of Aqueous Humor Secretion by Melatonin in Porcine Ciliary Epithelium. Int J Mol Sci 2023; 24:5789. [PMID: 36982863 PMCID: PMC10051954 DOI: 10.3390/ijms24065789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Secretion of melatonin, a natural hormone whose receptors are present in the ciliary epithelium, displays diurnal variation in the aqueous humor (AH), potentially contributing to the regulation of intraocular pressure. This study aimed to determine the effects of melatonin on AH secretion in porcine ciliary epithelium. The addition of 100 µM melatonin to both sides of the epithelium significantly increased the short-circuit current (Isc) by ~40%. Stromal administration alone had no effect on the Isc, but aqueous application triggered a 40% increase in Isc, similar to that of bilateral application without additive effect. Pre-treatment with niflumic acid abolished melatonin-induced Isc stimulation. More importantly, melatonin stimulated the fluid secretion across the intact ciliary epithelium by ~80% and elicited a sustained increase (~50-60%) in gap junctional permeability between pigmented ciliary epithelial (PE) cells and non-pigmented ciliary epithelial (NPE) cells. The expression of MT3 receptor was found to be >10-fold higher than that of MT1 and MT2 in porcine ciliary epithelium. Aqueous pre-treatment with MT1/MT2 antagonist luzindole failed to inhibit the melatonin-induced Isc response, while MT3 antagonist prazosin pre-treatment abolished the Isc stimulation. We conclude that melatonin facilitates Cl- and fluid movement from PE to NPE cells, thereby stimulating AH secretion via NPE-cell MT3 receptors.
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Affiliation(s)
- Ka-Lok Li
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | - Sze-Wan Shan
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong, China
| | - Fang-Yu Lin
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Department of Ophthalmology, Zhejiang University, Hangzhou 310027, China
- Department of Ophthalmology, Emory University, Atlanta, GA 30322, USA
| | - Choi-Ying Ling
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | - Nga-Wai Wong
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | - Hoi-Lam Li
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China
| | - Wei Han
- Department of Ophthalmology, Zhejiang University, Hangzhou 310027, China
| | - Chi-Ho To
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong, China
| | - Chi-Wai Do
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong, China
- Research Institute of Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong, China
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Impact of Primary RPE Cells in a Porcine Organotypic Co-Cultivation Model. Biomolecules 2022; 12:biom12070990. [PMID: 35883547 PMCID: PMC9313304 DOI: 10.3390/biom12070990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 07/04/2022] [Accepted: 07/13/2022] [Indexed: 12/10/2022] Open
Abstract
The pathological events of age-related macular degeneration are characterized by degenerative processes involving the photoreceptor cells, retinal pigment epithelium (RPE), and the Bruch's membrane as well as choroidal alterations. To mimic in vivo interactions between photoreceptor cells and RPE cells ex vivo, complex models are required. Hence, the aim of this study was to establish a porcine organotypic co-cultivation model and enlighten the interactions of photoreceptor and RPE cells, with a special emphasis on potential neuroprotective effects. Porcine neuroretina explants were cultured with primary porcine RPE cells (ppRPE) or medium derived from these cells (=conditioned medium). Neuroretina explants cultured alone served as controls. After eight days, RT-qPCR and immunohistology were performed to analyze photoreceptors, synapses, macroglia, microglia, complement factors, and pro-inflammatory cytokines (e.g., IL1B, IL6, TNF) in the neuroretina samples. The presence of ppRPE cells preserved photoreceptors, whereas synaptical density was unaltered. Interestingly, on an immunohistological as well as on an mRNA level, microglia and complement factors were comparable in all groups. Increased IL6 levels were noted in ppRPE and conditioned medium samples, while TNF was only upregulated in the ppRPE group. IL1B was elevated in conditioned medium samples. In conclusion, a co-cultivation of ppRPE cells and neuroretina seem to have beneficial effects on the neuroretina, preserving photoreceptors and maintaining synaptic vesicles in vitro. This organotypic co-cultivation model can be used to investigate the complex interactions between the retina and RPE cells, gain further insight into neurodegenerative pathomechanisms occurring in retinal diseases, and evaluate potential therapeutics.
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Wagner N, Safaei A, Vogt PA, Gammel MR, Dick HB, Schnichels S, Joachim SC. Coculture of ARPE-19 Cells and Porcine Neural Retina as an Ex Vivo Retinal Model. Altern Lab Anim 2022; 50:27-44. [PMID: 35302924 DOI: 10.1177/02611929221082662] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Neural retinal organ cultures are used to investigate ocular pathomechanisms. However, these cultures lack the essential retinal pigment epithelium (RPE) cells, which are part of the actual in vivo retina. To simulate a more realistic ex vivo model, porcine neural retina explants were cocultured with ARPE-19 cells (ARPE-19 group), which are derived from human RPE. To identify whether the entire cells or just the cell factors are necessary, in a second experimental group, porcine neural retina explants were cultured with medium derived from ARPE-19 cells (medium group). Individually cultured neural retina explants served as controls (control group). After 8 days, all neural retinas were analysed to evaluate retinal thickness, photoreceptors, microglia, complement factors and synapses (n = 6-8 per group). The neural retina thickness in the ARPE-19 group was significantly better preserved than in the control group (p = 0.031). Also, the number of L-cones was higher in the ARPE-19 group, as compared to the control group (p < 0.001). Furthermore, the ARPE-19 group displayed an increased presynaptic glutamate uptake (determined via vGluT1 labelling) and enhanced post-synaptic density (determined via PSD-95 labelling). Combined Iba1 and iNOS detection revealed only minor effects of ARPE-19 cells on microglial activity, with a slight downregulation of total microglia activity apparent in the medium group. Likewise, only minor beneficial effects on photoreceptors and synaptic structure were found in the medium group. This novel system offers the opportunity to investigate interactions between the neural retina and RPE cells, and suggests that the inclusion of a RPE feeder layer has beneficial effects on the ex vivo maintenance of neural retina. By modifying the culture conditions, this coculture model allows a better understanding of photoreceptor death and photoreceptor-RPE cell interactions in retinal diseases.
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Affiliation(s)
- Natalie Wagner
- Experimental Eye Research Institute, University Eye Hospital, 9142Ruhr-University Bochum, Germany
| | - Armin Safaei
- Experimental Eye Research Institute, University Eye Hospital, 9142Ruhr-University Bochum, Germany
| | - Pia A Vogt
- Experimental Eye Research Institute, University Eye Hospital, 9142Ruhr-University Bochum, Germany
| | - Maurice R Gammel
- Experimental Eye Research Institute, University Eye Hospital, 9142Ruhr-University Bochum, Germany
| | - H Burkhard Dick
- Experimental Eye Research Institute, University Eye Hospital, 9142Ruhr-University Bochum, Germany
| | - Sven Schnichels
- Centre for Ophthalmology Tübingen, University Eye Hospital Tübingen, Germany
| | - Stephanie C Joachim
- Experimental Eye Research Institute, University Eye Hospital, 9142Ruhr-University Bochum, Germany
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9
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Booler HS, Lejeune T, Sorden S, Gruebbel MM, Schafer KA, Short B, Farman C, Ramos MF, Bennet B, Yekkala K, Atzpodien EA, Turner OC, Brassard J, Foley G. Scientific and Regulatory Policy Committee Points to Consider: Fixation, Trimming, and Sectioning of Nonrodent Eyes and Ocular Tissues for Examination in Ocular and General Toxicity Studies. Toxicol Pathol 2021; 50:235-251. [PMID: 34693851 DOI: 10.1177/01926233211047562] [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: 11/17/2022]
Abstract
A Working Group of the Society of Toxicologic Pathology's Scientific and Regulatory Policy Committee conducted a technical and scientific review of current practices relating to the fixation, trimming, and sectioning of the nonrodent eye to identify key points and species-specific anatomical landmarks to consider when preparing and evaluating eyes of rabbits, dogs, minipigs, and nonhuman primates from ocular and general toxicity studies. The topics addressed in this Points to Consider article include determination of situations when more comprehensive evaluation of the globe and/or associated extraocular tissues should be implemented (expanded ocular sampling), and what constitutes expanded ocular sampling. In addition, this manuscript highlights the practical aspects of fixing, trimming, and sectioning the eye to ensure adequate histopathological evaluation of all major ocular structures, including the cone-dense areas (visual streak/macula/fovea) of the retina for rabbits, dogs, minipigs, and nonhuman primates, which is a current regulatory expectation for ocular toxicity studies.[Box: see text].
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Affiliation(s)
- Helen S Booler
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, Switzerland
| | | | | | - Margarita M Gruebbel
- Experimental Pathology Laboratories, Inc. (EPL, Inc.), Research Triangle Park, NC, USA
| | | | - Brian Short
- Brian Short Consulting, LLC, Laguna Beach, CA, USA
| | | | | | | | - Krishna Yekkala
- Janssen Pharmaceutical Companies of Johnson & Johnson, Spring House, PA, USA
| | - Elke-Astrid Atzpodien
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, Switzerland
| | - Oliver C Turner
- Novartis, Novartis Institutes for BioMedical Research, Preclinical Safety, East Hanover, NJ, USA
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Zhang Y, Erhard AL, Plagemann T, Eter N, Heiduschka P. A modified protocol for isolation of retinal microglia from the pig. Exp Eye Res 2021; 207:108584. [PMID: 33910034 DOI: 10.1016/j.exer.2021.108584] [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] [Received: 01/07/2021] [Revised: 03/31/2021] [Accepted: 04/14/2021] [Indexed: 11/27/2022]
Abstract
Microglia are the resident immune cells in the retina. To investigate their properties and behaviour, a reliable and yielding procedure to culture them is necessary. We here describe a way of isolation of microglial cells from the porcine retina, as pig eyes are similar to human eyes in size, structure and vasculature, including similarities in proteins and pathways. Retina was isolated from fresh pig eyes, dissociated by a mixture of collagenase, hyaluronidase and DNAse, and passed through a cell strainer. After triple centrifugation with decreasing velocity and re-suspension, cells were seeded into poly-d-lysine coated culture flasks and cultured using DMEM and macrophage-colony stimulating factor (M-CSF). Number of cells increased gradually during the first 10-14 days, till they could be split and used for experiments. Identity of isolated cells as microglia was assessed by immunostaining against the microglia/macrophage markers Iba1, CD11b, CD68, CD45 and TMEM119. Phagocytic function of microglia could be demonstrated by phagocytosis of fluorescence beads and their response to lipopolysaccharide (LPS). As a conclusion, we developed a protocol for isolation and cultivation of pig retinal microglial cells that are suitable for research in the laboratory.
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Affiliation(s)
- Yahan Zhang
- University of Münster Medical School, Department of Ophthalmology, Münster, Germany
| | - Anna Lena Erhard
- University of Münster Medical School, Department of Ophthalmology, Münster, Germany
| | - Tanja Plagemann
- University of Münster Medical School, Department of Ophthalmology, Münster, Germany
| | - Nicole Eter
- University of Münster Medical School, Department of Ophthalmology, Münster, Germany
| | - Peter Heiduschka
- University of Münster Medical School, Department of Ophthalmology, Münster, Germany.
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Relationship between retinal capillary vessel density of OCT angiography and intraocular pressure in pig. Sci Rep 2021; 11:8555. [PMID: 33879834 PMCID: PMC8058045 DOI: 10.1038/s41598-021-87689-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/31/2021] [Indexed: 12/04/2022] Open
Abstract
The purpose of this study was to evaluate density change in the retinal capillary plexus during intra ocular pressure (IOP) elevation in vitrectomized pigs’ eyes using optical coherence tomography angiography (OCTA). Eight eyes of eight micro pigs received vitrectomy and the IOP was controlled from 15 mmHg (baseline) to 105 mmHg in 15 mmHg increments using a vented-gas forced-infusion system, and then decreased back to normal IOP (recovery state). The spectral-domain OCTA device was set to scan an area of 8.8 × 4.4 mm (30° × 15°) above the optic nerve head for each IOP. The relative vessel density (rVAD) compared to baseline was determined for the total retinal blood flow (RBF) which included major retinal artery and venous vessels, radial peripapillary capillaries (RPCs), superficial (SVP), intermediate (IVP), and deep vascular plexus (DVP). The mean rVAD was 0.890 in RBF, 0.826 in RPCs, 0.817 in SVP, 0.819 in IVP, and 0.794 in DVP at 30 mmHg. While the rVAD of RBF and RPCs decreased to 0.504 and 0.541 at 45 mmHg, the SVP, IVP, and DVP decreased to 0.433, 0.359, and 0.345, respectively. When IOP was normalized, the rVAD was recovered in all layers and the VAD of RBF, IVP, and DVP were higher than baseline (P = 0.040, 0.019, and 0.019, respectively). Retinal capillary density deterioration in each layer was found from 30 mmHg using an OCTA system which showed excellent depth-resolved segmentation of retinal capillary layers even at higher IOPs. Reduction in VAD showed full recovery after IOP normalization.
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12
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Yu PK, Mehnert A, Athwal A, Sarunic MV, Yu DY. Use of the Retinal Vascular Histology to Validate an Optical Coherence Tomography Angiography Technique. Transl Vis Sci Technol 2021; 10:29. [PMID: 33520424 PMCID: PMC7817878 DOI: 10.1167/tvst.10.1.29] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/15/2020] [Indexed: 12/29/2022] Open
Abstract
Purpose To determine the fidelity of optical coherence tomography angiography (OCTA) techniques by direct comparison of the retinal capillary network images obtained from the same region as imaged by OCTA and high-resolution confocal microscope. Method Ten porcine eyes were perfused with red blood cells for OCTA image acquisition from the area centralis and then perfusion-fixed, and the vessels were labeled for confocal imaging. Two approaches involving post-processing of two-dimensional projection images and vessel tracking on three dimensional image stacks were used to obtain quantitative measurements. Data collected include vessel density, length of visible vessel track, count of visible branch points, vessel track depth, vessel diameter, angle of vessel descent, and angle of dive for comparison and analysis. Results Comparing vascular images acquired from OCTA and confocal microscopy, we found (1) a good representation of the larger caliber retinal vessels, (2) an underrepresentation of retinal microvessels smaller than 10 µm and branch points in all four retinal vascular plexuses, particularly the intermediate capillary plexus, (3) reduced visibility associated with an increase in the angle of descent, (4) a tendency to loss visibility of vessel track at a branch point or during a sharp dive, and (5) a reduction in visibility with increase in retinal depth on OCTA images. Conclusions Current OCTA techniques can visualize the retinal capillary network, but some types of capillaries cannot be detected by OCTA, particularly in the middle to deeper layers. Translational Relevance The information indicates the limitation in clinical use and scopes for improvement in the current OCTA technologies.
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Affiliation(s)
- Paula K Yu
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Australia.,Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Andrew Mehnert
- Centre for Microscopy Characterisation and Analysis, University of Western Australia, Perth, Australia.,National Imaging Facility, Australia
| | - Arman Athwal
- Lions Eye Institute, Nedlands, Western Australia, Australia.,School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Marinko V Sarunic
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Dao-Yi Yu
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Australia.,Lions Eye Institute, Nedlands, Western Australia, Australia
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13
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ROCK inhibition reduces morphological and functional damage to rod synapses after retinal injury. Sci Rep 2021; 11:692. [PMID: 33436892 PMCID: PMC7804129 DOI: 10.1038/s41598-020-80267-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/16/2020] [Indexed: 01/29/2023] Open
Abstract
Retinal detachment (RD) causes damage, including disjunction, of the rod photoreceptor-bipolar synapse, which disrupts vision and may contribute to the poor visual recovery observed after retinal reattachment surgery. We created a model of iatrogenic RD in adult female pigs to study damage to the rod-bipolar synapse after injury and the ability of a highly specific Rho-kinase (ROCK) inhibitor to preserve synaptic structure and function. This model mimics procedures used in humans when viral vectors or cells are injected subretinally for treatment of retinal disease. Synaptic disjunction by retraction of rod spherules, quantified by image analysis of confocal sections, was present 2 h after detachment and remained 2 days later even though the retina had spontaneously reattached by then. Moreover, spherule retraction occurred in attached retina 1-2 cms from detached retina. Synaptic damage was significantly reduced by ROCK inhibition in detached retina whether injected subretinally or intravitreally. Dark-adapted full-field electroretinograms were recorded in reattached retinas to assess rod-specific function. Reduction in synaptic injury correlated with increases in rod-driven responses in drug-treated eyes. Thus, ROCK inhibition helps prevent synaptic damage and improves functional outcomes after retinal injury and may be a useful adjunctive treatment in iatrogenic RD and other retinal degenerative diseases.
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14
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Sørensen NB. Subretinal surgery: functional and histological consequences of entry into the subretinal space. Acta Ophthalmol 2019; 97 Suppl A114:1-23. [PMID: 31709751 DOI: 10.1111/aos.14249] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND OBJECTIVES Gene-therapy, stem-cell transplantation and surgical robots hold the potential for treatment of currently untreatable retinal degenerative diseases. All of the techniques require entry into the subretinal space, which is a potential space located between the retina and the retinal pigment epithelium (RPE). Knowledge about obstacles and critical steps in relation to subretinal procedures is therefore needed. This thesis explores the functional and histological consequences of separation of the retina from the RPE, extensive RPE damage, a large cut in the retina (retinotomy) and RPE phagocytosis in a porcine model. METHODS Experiments were performed in 106 female domestic pigs of Danish landrace distributed over five studies. Under general anesthesia, different procedures for expansion of the subretinal space were conducted. Outcomes were visual function measured electrophysiologically with multifocal electroretinogram (mfERG) and retinal morphology examined histologically. Study I: The effect of anesthesia on mfERG was examined by repeated recordings for 3 hr in isoflurane or propofol anesthesia. Outcome was mfERG amplitude. Study II: Consequences of a large separation of the photoreceptors from the RPE were examined by injecting a perfluorocarbon-liquid (decalin) into the subretinal space. Two weeks after, in a second surgery, decalin was withdrawn. Outcomes were mfERG and histology 4 weeks after decalin injection. Study III: Extensive RPE damage was examined by expanding the subretinal space with saline and removing large sheets of RPE-cells through a retinotomy. Outcomes were mfERG and histology 2, 4 and 6 weeks after the procedure. Study IV: Consequences of a large retinotomy were examined by similar procedures as in Study III, but in study IV only a few RPE cells were removed. Outcomes were mfERG and histology 2 and 6 weeks after surgery. Study V: Clearance of the subretinal space was examined by injecting fluorescent latex beads of various sizes into the subretinal space. Outcome was histologic location of the beads at different time intervals after the procedure. RESULTS Study I: MfERG amplitudes decreased linearly as a function of time in propofol or isoflurane anesthesia. Duration of mfERG recording could be decreased without compromising quality, and thereby could time in anesthesia be reduced. Study II: MfERG and histology remained normal after reattachment of a large and 2-week long separation of the photoreceptors and RPE. Repeated entry into the subretinal space was well tolerated. Fluid injection into the subretinal space constitutes a risk of RPE-damage. Study III: Removal of large sheets of retinal pigment epithelial cells triggered a widespread rhegmatogenous-like retinal detachment resulting in visual loss. Study IV: A large retinotomy with limited damage of the RPE was well tolerated, and visual function was preserved. Study V: Subretinal latex beads up to 4 μm were phagocytosed by the RPE and passed into the sub-RPE space. Beads up to 2 μm travelled further through the Bruch's membrane and were found in the choroid, sclera and inside blood vessels. CONCLUSION A large expansion of the subretinal space, repeated entry, a large retinotomy and limited RPE damage is well tolerated and retinal function is preserved. Subretinal injection of fluid can damage the RPE and extensive RPE damage can induce a rhegmatogenous-like retinal detachment with loss of visual function. Foreign substances exit the subretinal space and can reach the systemic circulation.
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Affiliation(s)
- Nina Buus Sørensen
- Department of Ophthalmology Copenhagen University Hospital Rigshospitalet København Denmark
- Department of Neurology Zealand University Hospital Køge Denmark
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15
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Species Differences in the Nutrition of Retinal Ganglion Cells among Mammals Frequently Used as Animal Models. Cells 2019; 8:cells8101254. [PMID: 31615137 PMCID: PMC6829614 DOI: 10.3390/cells8101254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/26/2019] [Accepted: 10/13/2019] [Indexed: 12/23/2022] Open
Abstract
The diffusion rate for proper nutrition of the inner retina depends mainly on four factors which are discussed in this review: 1. The diffusion distance between blood and retinal ganglion cells shows morphological variants in different mammalian species, namely a choroidal nutrition type, a retinal nutrition type, and a mixture of both types. 2. Low oxygen concentration levels in the inner retina force the diffusion of oxygen especially in the choroidal nutrition type. Other nutrients might be supplied by surrounding cells, mainly Müller cells. 3. Diffusion in the eye is influenced by the intraocular pressure, which is vital for the retinal ganglion cells but might also influence their proper function. Again, the nutrition types established might explain the differences in normal intraocular pressure levels among different species. 4. Temperature is a critical feature in the eye which has to be buffered to avoid neuronal damage. The most effective buffer system is the increased blood turnover in the choroid which has to be established in all species.
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16
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Wang W, Halasz E, Townes-Anderson E. Actin Dynamics, Regulated by RhoA-LIMK-Cofilin Signaling, Mediates Rod Photoreceptor Axonal Retraction After Retinal Injury. Invest Ophthalmol Vis Sci 2019; 60:2274-2285. [PMID: 31112612 PMCID: PMC6530517 DOI: 10.1167/iovs.18-26077] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Purpose Retraction of the axon terminals of rod photoreceptors after retinal detachment breaks the first synapse in the visual pathway, resulting in visual impairment. Previous work showed that the mechanism of axonal retraction involves RhoA signaling and its downstream effector LIM Kinase (LIMK) activation. We examined the response of the downstream component cofilin, a direct binding protein of actin filaments, as well as the regulation by RhoA-LIMK-Cofilin signaling of actin assembly/disassembly, in the presynaptic ribbon terminal of injured rod cells. Methods Injury was produced by retinal detachment or rod cell isolation. Detached porcine retina was probed for levels and localization of phosphorylated cofilin with Western blots and confocal microscopy, whereas rod cell cultures of dissociated salamander retina were examined for filamentous actin assembly/disassembly with a barbed end assay and phalloidin staining. Results A detachment increased phosphorylation of cofilin in retinal explants; phosphorylation occurred in rod terminals in sections of detached retina. Isolation of rod cells resulted in axon retraction accompanied by an increase in actin barbed ends and a decrease in net filament labeling. All changes were significantly reduced by either Rho kinase (ROCK) or LIMK inhibition, using Y27632 or BMS-5, respectively. Cytochalasin D also reduced retraction and stabilized filaments in isolated rod cells. Conclusions These results indicate that actin depolymerization via activation of RhoA downstream kinases and cofilin contributes to axon retraction. Preventing depolymerization, in addition to actomyosin contraction, may stabilize ribbon synapses after trauma.
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Affiliation(s)
- Weiwei Wang
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey, United States
| | - Eva Halasz
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey, United States
| | - Ellen Townes-Anderson
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey, United States
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17
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Lim RR, Hainsworth DP, Mohan RR, Chaurasia SS. Characterization of a functionally active primary microglial cell culture from the pig retina. Exp Eye Res 2019; 185:107670. [PMID: 31103710 DOI: 10.1016/j.exer.2019.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 02/06/2023]
Abstract
Retinal inflammation is an integral component of many retinal diseases including diabetic retinopathy (DR), age-related macular degeneration (AMD) and retinopathy of prematurity (ROP). Inflammation is commonly initiated and perpetuated by myeloid-derived immune cells. In the retina, microglial cells are resident macrophages with myeloid origins, which acts as the first responders involved in the innate immune system. To understand the disease pathogenesis, the use of isolated retinal cell culture model is vital for the examination of multiple cellular responses to injury or trauma. The pig retina resembles human retina in terms of tissue architecture, vasculature, and topography. Additionally, it is a better model than the rodent retina because of the presence of the pseudomacula. In the present study, we sought to establish and characterize pig retinal primary microglial cell (pMicroglia) culture. We used pig eyes from the local abattoir and optimized pMicroglia cultures using multiple cell culture conditions and methods. The best results were obtained by seeding cells in DMEM-high glucose media for 18 days followed by shaking of the culture plate. The resulting pMicroglia were characterized by cellular morphology, phenotype, and immunostaining with Iba-1, CD68, P2Y12, CD163, CD14, and Isolectin GS-IB4. Generated pMicroglia were found functionally active in phagocytosis assay and responsive to lipopolysaccharides (LPS) in dose-dependent production of IL-1β. Furthermore, they showed increased secretion of pro-inflammatory cytokines with LPS treatment. Thus, we report a novel and reproducible method for the isolation of primary microglial cells from pig eyes, which may be useful for studying retinal diseases.
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Affiliation(s)
- Rayne R Lim
- Ocular Immunology and Angiogenesis Lab, Department of Veterinary Medicine & Surgery, University of Missouri, Columbia, MO, 65211, USA; Department of Biomedical Sciences, University of Missouri, Columbia, MO, 65211, USA; Harry S. Truman Memorial Veteran Hospital, Columbia, MO, 65201, USA
| | - Dean P Hainsworth
- Mason Eye Institute, University of Missouri, Columbia, MO, 65211, USA
| | - Rajiv R Mohan
- Ocular Immunology and Angiogenesis Lab, Department of Veterinary Medicine & Surgery, University of Missouri, Columbia, MO, 65211, USA; Department of Biomedical Sciences, University of Missouri, Columbia, MO, 65211, USA; Harry S. Truman Memorial Veteran Hospital, Columbia, MO, 65201, USA; Mason Eye Institute, University of Missouri, Columbia, MO, 65211, USA
| | - Shyam S Chaurasia
- Ocular Immunology and Angiogenesis Lab, Department of Veterinary Medicine & Surgery, University of Missouri, Columbia, MO, 65211, USA; Department of Biomedical Sciences, University of Missouri, Columbia, MO, 65211, USA; Harry S. Truman Memorial Veteran Hospital, Columbia, MO, 65201, USA.
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18
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Rousou C, Hoogenboom P, van Overdam K, Storm G, Dorrestijn J, Mastrobattista E. A technical protocol for an experimental ex vivo model using arterially perfused porcine eyes. Exp Eye Res 2019; 181:171-177. [DOI: 10.1016/j.exer.2019.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/10/2019] [Accepted: 02/03/2019] [Indexed: 11/24/2022]
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19
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Christiansen AT, Sørensen NB, Haanes KA, Blixt FW, la Cour M, Warfvinge K, Klemp K, Woldbye DPD, Kiilgaard JF. Neuropeptide Y treatment induces retinal vasoconstriction and causes functional and histological retinal damage in a porcine ischaemia model. Acta Ophthalmol 2018; 96:812-820. [PMID: 30218483 DOI: 10.1111/aos.13806] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 04/04/2018] [Indexed: 01/10/2023]
Abstract
PURPOSE To investigate the effects of intravitreal neuropeptide Y (NPY) treatment following acute retinal ischaemia in an in vivo porcine model. In addition, we evaluated the vasoconstrictive potential of NPY on porcine retinal arteries ex vivo. METHODS Twelve pigs underwent induced retinal ischaemia by elevated intraocular pressure clamping the ocular perfusion pressure at 5 mmHg for 2 hr followed by intravitreal injection of NPY or vehicle. After 4 weeks, retinas were evaluated functionally by standard and global-flash multifocal electroretinogram (mfERG) and histologically by thickness of retinal layers and number of ganglion cells. Additionally, the vasoconstrictive effects of NPY and its involved receptors were tested using wire myographs and NPY receptor antagonists on porcine retinal arteries. RESULTS Intravitreal injection of NPY after induced ischaemia caused a significant reduction in the mean induced component (IC) amplitude ratio (treated/normal eye) compared to vehicle-treated eyes. This reduction was accompanied by histological damage, where NPY treatment reduced the mean thickness of inner retinal layers and number of ganglion cells. In retinal arteries, NPY-induced vasoconstriction to a plateau of approximately 65% of potassium-induced constriction. This effect appeared to be mediated via Y1 and Y2, but not Y5. CONCLUSION In seeming contrast to previous in vitro studies, intravitreal NPY treatment caused functional and histological damage compared to vehicle after a retinal ischaemic insult. Furthermore, we showed for the first time that NPY induces Y1- and Y2- but not Y5-mediated vasoconstriction in retinal arteries. This constriction could explain the worsening in vivo effect induced by NPY treatment following an ischaemic insult and suggests that future studies on exploring the neuroprotective effects of NPY might focus on other receptors than Y1 and Y2.
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Affiliation(s)
- Anders T. Christiansen
- Laboratory of Neural Plasticity; Department of Neuroscience; University of Copenhagen; Copenhagen Denmark
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Nina B. Sørensen
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Kristian A. Haanes
- Department of Clinical Experimental Research; Glostrup Research Institute; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Frank W. Blixt
- Department of Clinical Sciences; Division of Experimental Vascular Research; Lund University; Lund Sweden
| | - Morten la Cour
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Karin Warfvinge
- Department of Clinical Experimental Research; Glostrup Research Institute; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Kristian Klemp
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - David P. D. Woldbye
- Laboratory of Neural Plasticity; Department of Neuroscience; University of Copenhagen; Copenhagen Denmark
| | - Jens F. Kiilgaard
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
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20
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Li SKL, Shan SW, Li HL, Cheng AKW, Pan F, Yip SP, Civan MM, To CH, Do CW. Characterization and Regulation of Gap Junctions in Porcine Ciliary Epithelium. ACTA ACUST UNITED AC 2018; 59:3461-3468. [DOI: 10.1167/iovs.18-24682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Stanley Ka-Lok Li
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Sze-Wan Shan
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Hoi-Lam Li
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Angela King-Wah Cheng
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Feng Pan
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Shea-Ping Yip
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Mortimer M. Civan
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Chi-Ho To
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Chi-Wai Do
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
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Zhang Z, Uchida Y, Hirano S, Ando D, Kubo Y, Auriola S, Akanuma SI, Hosoya KI, Urtti A, Terasaki T, Tachikawa M. Inner Blood–Retinal Barrier Dominantly Expresses Breast Cancer Resistance Protein: Comparative Quantitative Targeted Absolute Proteomics Study of CNS Barriers in Pig. Mol Pharm 2017; 14:3729-3738. [DOI: 10.1021/acs.molpharmaceut.7b00493] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhengyu Zhang
- Division
of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical
Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Yasuo Uchida
- Division
of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical
Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Satoshi Hirano
- Division
of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical
Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Daisuke Ando
- Department
of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama,
Sugitani, Toyama 930-0194, Japan
| | - Yoshiyuki Kubo
- Department
of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama,
Sugitani, Toyama 930-0194, Japan
| | - Seppo Auriola
- Division
of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical
Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
- School
of Pharmacy, University of Eastern Finland, Kuopio FI-70211, Finland
| | - Shin-ichi Akanuma
- Department
of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama,
Sugitani, Toyama 930-0194, Japan
| | - Ken-ichi Hosoya
- Department
of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama,
Sugitani, Toyama 930-0194, Japan
| | - Arto Urtti
- School
of Pharmacy, University of Eastern Finland, Kuopio FI-70211, Finland
- Faculty
of Pharmacy, University of Helsinki, Helsinki 00014, Finland
| | - Tetsuya Terasaki
- Division
of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical
Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Masanori Tachikawa
- Division
of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical
Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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22
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Townes-Anderson E, Wang J, Halász É, Sugino I, Pitler A, Whitehead I, Zarbin M. Fasudil, a Clinically Used ROCK Inhibitor, Stabilizes Rod Photoreceptor Synapses after Retinal Detachment. Transl Vis Sci Technol 2017; 6:22. [PMID: 28660097 PMCID: PMC5482187 DOI: 10.1167/tvst.6.3.22] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 05/08/2017] [Indexed: 12/20/2022] Open
Abstract
Purpose Retinal detachment disrupts the rod-bipolar synapse in the outer plexiform layer by retraction of rod axons. We showed that breakage is due to RhoA activation whereas inhibition of Rho kinase (ROCK), using Y27632, reduces synaptic damage. We test whether the ROCK inhibitor fasudil, used for other clinical applications, can prevent synaptic injury after detachment. Methods Detachments were made in pigs by subretinal injection of balanced salt solution (BSS) or fasudil (1, 10 mM). In some animals, fasudil was injected intravitreally after BSS-induced detachment. After 2 to 4 hours, retinae were fixed for immunocytochemistry and confocal microscopy. Axon retraction was quantified by imaging synaptic vesicle label in the outer nuclear layer. Apoptosis was analyzed using propidium iodide staining. For biochemical analysis by Western blotting, retinal explants, detached from retinal pigmented epithelium, were cultured for 2 hours. Results Subretinal injection of fasudil (10 mM) reduced retraction of rod spherules by 51.3% compared to control detachments (n = 3 pigs, P = 0.002). Intravitreal injection of 10 mM fasudil, a more clinically feasible route of administration, also reduced retraction (28.7%, n = 5, P < 0.05). Controls had no photoreceptor degeneration at 2 hours, but by 4 hours apoptosis was evident. Fasudil 10 mM reduced pyknotic nuclei by 55.7% (n = 4, P < 0.001). Phosphorylation of cofilin and myosin light chain, downstream effectors of ROCK, was decreased with 30 μM fasudil (n = 8–10 explants, P < 0.05). Conclusions Inhibition of ROCK signaling with fasudil reduced photoreceptor degeneration and preserved the rod-bipolar synapse after retinal detachment. Translational Relevance These results support the possibility, previously tested with Y27632, that ROCK inhibition may attenuate synaptic damage in iatrogenic detachments.
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Affiliation(s)
- Ellen Townes-Anderson
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Jianfeng Wang
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Éva Halász
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Ilene Sugino
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Amy Pitler
- Department of Microbiology, Biochemistry, and Medical Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Ian Whitehead
- Department of Microbiology, Biochemistry, and Medical Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Marco Zarbin
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, NJ, USA
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23
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Wang J, Zarbin M, Sugino I, Whitehead I, Townes-Anderson E. RhoA Signaling and Synaptic Damage Occur Within Hours in a Live Pig Model of CNS Injury, Retinal Detachment. Invest Ophthalmol Vis Sci 2017; 57:3892-906. [PMID: 27472075 PMCID: PMC4974026 DOI: 10.1167/iovs.16-19447] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PURPOSE The RhoA pathway is activated after retinal injury. However, the time of onset and consequences of activation are unknown in vivo. Based on in vitro studies we focused on a period 2 hours after retinal detachment, in pig, an animal whose retina is holangiotic and contains cones. METHODS Under anesthesia, retinal detachments were created by subretinal injection of a balanced salt solution. Two hours later, animals were sacrificed and enucleated for GTPase activity assays and quantitative Western blot and confocal microscopy analyses. RESULTS RhoA activity with detachment was increased 1.5-fold compared to that in normal eyes or in eyes that had undergone vitrectomy only. Increased phosphorylation of myosin light chain, a RhoA effector, also occurred. By 2 hours, rod cells had retracted their terminals toward their cell bodies, disrupting the photoreceptor-to-bipolar synapse and producing significant numbers of spherules with SV2 immunolabel in the outer nuclear layer of the retina. In eyes with detachment, distant retina that remained attached also showed significant increases in RhoA activity and synaptic disjunction. Increases in RAC1 activity and glial fibrillary acidic protein (GFAP) were not specific for detachment, and sprouting of bipolar dendrites, reported for longer detachments, was not seen. The RhoA kinase inhibitor Y27632 significantly reduced axonal retraction by rod cells. CONCLUSIONS Activation of the RhoA pathway occurs quickly after injury and promotes synaptic damage that can be controlled by RhoA kinase inhibition. We suggest that retinal detachment joins the list of central nervous system injuries, such as stroke and spinal cord injury, that should be considered for rapid therapeutic intervention.
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Affiliation(s)
- Jianfeng Wang
- Department of Pharmacology Physiology, and Neuroscience, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
| | - Marco Zarbin
- Institute of Ophthalmology and Visual Science, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
| | - Ilene Sugino
- Institute of Ophthalmology and Visual Science, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
| | - Ian Whitehead
- Department of Microbiology, Biochemistry, and Medical Genetics, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
| | - Ellen Townes-Anderson
- Department of Pharmacology Physiology, and Neuroscience, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
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NEW INSIGHT INTO THE MACULAR DEEP VASCULAR PLEXUS IMAGED BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Retina 2015; 35:2347-52. [DOI: 10.1097/iae.0000000000000839] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Attenuating Cardiac Pulsations within the Cochlea: Structure and Function of Tortuous Vessels Feeding Stria Vascularis. ISRN OTOLARYNGOLOGY 2013; 2013:941757. [PMID: 23762624 PMCID: PMC3671538 DOI: 10.1155/2013/941757] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 04/18/2013] [Indexed: 11/17/2022]
Abstract
The mammalian ear has an extraordinary capacity to detect very low-level acoustic signals from the environment. Sound pressures as low as a few μ Pa (-10 dB SPL) can activate cochlear hair cells. To achieve this sensitivity, biological noise has to be minimized including that generated by cardiovascular pulsation. Generally, cardiac pressure changes are transmitted to most peripheral capillary beds; however, such signals within the stria vascularis of the cochlea would be highly disruptive. Not least, it would result in a constant auditory sensation of heartbeat. We investigate special adaptations in cochlear vasculature that serve to attenuate cardiac pulse signals. We describe the structure of tortuous arterioles that feed stria vascularis as seen in corrosion casts of the cochlea. We provide a mathematical model to explain the role of this unique vascular anatomy in dampening pulsatile blood flow to the stria vascularis.
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Preretinal partial pressure of oxygen gradients before and after experimental pars plana vitrectomy. Retina 2013; 33:170-8. [PMID: 22972446 DOI: 10.1097/iae.0b013e318261a6b5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate preretinal partial pressure of oxygen (PO2) gradients before and after experimental pars plana vitrectomy. METHODS Arteriolar, venous, and intervascular preretinal PO2 gradients were recorded in 7 minipigs during slow withdrawal of oxygen-sensitive microelectrodes (10-μm tip diameter) from the vitreoretinal interface to 2 mm into the vitreous cavity. Recordings were repeated after pars plana vitrectomy and balanced salt solution (BSS) intraocular perfusion. RESULTS Arteriolar, venous, and intervascular preretinal PO2 at the vitreoretinal interface were 62.3 ± 13.8, 22.5 ± 3.3, and 17.0 ± 7.5 mmHg, respectively, before vitrectomy; 97.7 ± 19.9, 40.0 ± 21.9, and 56.3 ± 28.4 mmHg, respectively, immediately after vitrectomy; and 59.0 ± 27.4, 25.2 ± 3.0, and 21.5 ± 4.5 mmHg, respectively, 2½ hours after interruption of BSS perfusion. PO2 2 mm from the vitreoretinal interface was 28.4 ± 3.6 mmHg before vitrectomy; 151.8 ± 4.5 mmHg immediately after vitrectomy; and 34.8 ± 4.1 mmHg 2½ hours after interruption of BSS perfusion. PO2 gradients were still present after vitrectomy, with the same patterns as before vitrectomy. CONCLUSION Preretinal PO2 gradients are not eliminated after pars plana vitrectomy. During BSS perfusion, vitreous cavity PO2 is very high. Interruption of BSS perfusion evokes progressive equilibration of vitreous cavity PO2 with concomitant progressive return of preretinal PO2 gradients to their previtrectomy patterns. This indicates that preretinal diffusion of oxygen is not altered after vitrectomy. The beneficial effect of vitrectomy in ischemic retinal diseases or macular edema may be related to other mechanisms, such as increased oxygen convection currents or removal of growth factors and cytokines secreted in the vitreous.
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Fernandez-Bueno I, Rodriguez de la Rua E, Hileeto D, Parrado ML, Regueiro-Purriños M, Sala-Puigdollers A, Srivastava GK, Gonzalo-Orden JM, Pastor JC. Histology and immunochemistry evaluation of autologous translocation of retinal pigment epithelium-choroid graft in porcine eyes. Acta Ophthalmol 2013; 91:e125-32. [PMID: 23256869 DOI: 10.1111/aos.12001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To evaluate structure and cellular functionality of retinal pigment epithelium (RPE)-choroid grafts after autologous translocation in porcine eyes. METHODS Retinal pigment epithelium-choroid grafts were obtained from the nasal midperiphery donor site and translocated to the central area in 12 pigs (12 eyes). Grafts were placed under the central retina through a retinotomy. Ophthalmoscopic and pathological evaluations were performed immediately (n = 1) and at 15 (n = 3) and 30 (n = 3) days after surgery. Untranslocated nasal RPE-choroid grafts were obtained at time of surgery and used as controls. Specimens were evaluated by standard histology and by immunochemical studies of RPE65, CRALBP and GFAP. RESULTS Five animals were lost to follow-up owing to surgery or anaesthesia complications. Ophthalmoscopic examination revealed that the grafts remained in place at all time-points studied. Fifteen and thirty days postsurgery, some areas of the transplanted RPE maintained a monolayered structure. Retinal pigment epithelium cells were firmly attached to Bruch's membrane and predominantly preserved polarity and pigment distribution. However, RPE65, CRALBP and GFAP patterns of expression and distribution were diminished and modified during follow-up. Ophthalmoscopic retinal detachment and proliferative vitreoretinopathy (PVR), confirmed by microscopic evaluation, complicated all cases at 30 days of follow-up. CONCLUSION Autologous RPE-choroid grafts survived up to 30 days in porcine eyes. Histological and immunochemical evaluation revealed preserved transplanted RPE cells morphology accompanied by alterations in the immunoreactivity expression of functional proteins, and development of significant PVR. The data presented in this manuscript provide insights into the fate, viability and cellular functionality of the transplanted RPE-choroid graft, serving as foundation for further knowledge and improvement of this technique.
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Affiliation(s)
- Ivan Fernandez-Bueno
- Universitary Institute of Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain.
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Gullapalli VK, Khodair MA, Wang H, Sugino IK, Madreperla S, Zarbin MA. Transplantation Frontiers. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00125-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Su SW, Catherall M, Payne S. The influence of network structure on the transport of blood in the human cerebral microvasculature. Microcirculation 2012; 19:175-87. [PMID: 22111581 DOI: 10.1111/j.1549-8719.2011.00148.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this article, we explore how the structural properties of miniature networks influence the transport of blood through the human cerebral microvasculature. We propose four methods for generating such networks, and investigate both how the resulting network properties match available experimental data from the human cortex and how these properties affect the flow of blood through the networks. As the nature of such microvascular flow patterns is inherently random, we run multiple simulations. We find that the modified spanning tree method produces artificial networks having characteristics closest to those of the microvasculature in human brain, and also allows for high network flow passage per unit material cost, being statistically significantly better than three other methods considered here. Such results are potentially extremely valuable in interpreting experimental data acquired from humans and in improving our understanding of cerebral blood flow at this very small length scale. This could have a significant impact on improving clinical outcomes for vascular brain diseases, particularly vascular dementia, where localized flow patterns are very important.
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Affiliation(s)
- Shen-Wei Su
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK.
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Lopes M, Goupille O, Saint Cloment C, Robert B. Msx1 is expressed in retina endothelial cells at artery branching sites. Biol Open 2012; 1:376-84. [PMID: 23213427 PMCID: PMC3509462 DOI: 10.1242/bio.2012017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1(lacZ) is expressed in vascular smooth muscle cells (VSMCs) and pericytes, and that Msx2(lacZ) is also expressed in VSMCs as well as in a few endothelial cells (ECs). The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the retina has been intensely used for angiogenesis studies, whereas the choroid has been much less investigated. Using the Msx1(lacZ) and Msx2(lacZ) reporter alleles, we observed that Msx2 is not expressed in the eye vascular tree in contrast to Msx1, for which we establish the spatial and temporal expression pattern in these tissues. In the retina, expression of Msx1 takes place from P3, and by P10, it becomes confined to a subpopulation of ECs at branching points of superficial arterioles. These branching sites are characterized by a subpopulation of mural cells that also show specific expression programs. Specific Msx gene inactivation in the endothelium, using Msx1 and Msx2 conditional mutant alleles together with a Tie2-Cre transgene, did not lead to conspicuous structural defects in the retinal vascular network. Expression of Msx1 at branching sites might therefore be linked to vessel physiology. The retinal blood flow is autonomously regulated and perfusion of capillaries has been proposed to depend on arteriolar precapillary structures that might be the sites for Msx1 expression. On the other hand, branching sites are subject to shear stress that might induce Msx1 expression. In the choroid vascular layer Msx1(lacZ) is expressed more broadly and dynamically. At birth Msx1(lacZ) expression takes place in the endothelium but at P21 its expression has shifted towards the mural layer. We discuss the possible functions of Msx1 in the eye vasculature.
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Affiliation(s)
- Miguel Lopes
- Present address: IPSEN Innovation, Scientific affairs department, 5 Avenue du Canada, 91966 Les Ulis Cedex, France
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Hein TW, Ren Y, Potts LB, Yuan Z, Kuo E, Rosa RH, Kuo L. Acute retinal ischemia inhibits endothelium-dependent nitric oxide-mediated dilation of retinal arterioles via enhanced superoxide production. Invest Ophthalmol Vis Sci 2012; 53:30-6. [PMID: 22110081 DOI: 10.1167/iovs.11-8753] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Because retinal vascular disease is associated with ischemia and increased oxidative stress, the vasodilator function of retinal arterioles was examined after retinal ischemia induced by elevated intraocular pressure (IOP). The role of superoxide anions in the development of vascular dysfunction was assessed. METHODS IOP was increased and maintained at 80 to 90 mm Hg for 30, 60, or 90 minutes by infusing saline into the anterior chamber of a porcine eye. The fellow eye with normal IOP (10-20 mm Hg) served as control. In some pigs, superoxide dismutase mimetic TEMPOL (1 mM) or vehicle (saline) was injected intravitreally before IOP elevation. After enucleation, retinal arterioles were isolated and pressurized without flow for functional analysis by recording diameter changes using videomicroscopic techniques. Dihydroethidium (DHE) was used to detect superoxide production in isolated retinal arterioles. RESULTS Isolated retinal arterioles developed stable basal tone and the vasodilations to endothelium-dependent nitric oxide (NO)-mediated agonists bradykinin and L-lactate were significantly reduced only by 90 minutes of ischemia. However, vasodilation to endothelium-independent NO donor sodium nitroprusside was unaffected after all time periods of ischemia. DHE staining showed that 90 minutes of ischemia significantly increased superoxide levels in retinal arterioles. Intravitreal injection of membrane-permeable radical scavenger but not vehicle before ischemia prevented elevation of vascular superoxide and preserved bradykinin-induced dilation. CONCLUSIONS Endothelium-dependent NO-mediated dilation of retinal arterioles is impaired by 90 minutes of ischemia induced by elevated IOP. The inhibitory effect appears to be mediated by the alteration of NO signaling via vascular superoxide.
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Affiliation(s)
- Travis W Hein
- Department of Ophthalmology, Scott &White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, USA.
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Toxicity profiles of subretinal indocyanine green, Brilliant Blue G, and triamcinolone acetonide: a comparative study. Graefes Arch Clin Exp Ophthalmol 2011; 250:669-77. [PMID: 22173216 DOI: 10.1007/s00417-011-1886-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 11/16/2011] [Accepted: 11/25/2011] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND This study introduces a novel porcine model to examine the histopathological and electrophysiological consequences of retinotoxicity exerted by dyes commonly used for internal limiting membrane (ILM) staining. METHODS Indocyanine green (ICG) 0.5 mg/ml, Brilliant Blue G (BBG) 0.25 mg/ml and triamcinolone acetonide (TA) 13 mg/ml was injected subretinally in 12 vitrectomized pig eyes. At 6 weeks, retinas were examined by multifocal electroretinography (mfERG), ophthalmoscopy, fluorescein angiograpy, histopathology, and apoptosis assay. RESULTS mfERG responses were significantly lower in ICG-injected eyes than in healthy fellow eyes (p = 0.039). The ratio between injected eyes and healthy fellow eyes was lower in the ICG group than in the BBG (p = 0.009) and TA group (p = 0.025). No difference between BBG and TA existed. All retinas were reattached, and fluorescein angiographies showed a window defect corresponding to the injected areas but no blood-retina barrier break-down. Histopathology confirmed damage to the outer retina after ICG, but not after BBG and TA. No apoptosis was found at 6 weeks. CONCLUSIONS Subretinal ICG induces histological and functional damage to the retina, suggesting that ICG should be used with caution in macular hole surgery, where subretinal migration can occur. In contrast, BBG and TA appear safe after subretinal injection.
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Sørensen NF, Ejstrup R, Svahn TF, Sander B, Kiilgaard J, la Cour M. The effect of subretinal viscoelastics on the porcine retinal function. Graefes Arch Clin Exp Ophthalmol 2011; 250:79-86. [PMID: 21870087 DOI: 10.1007/s00417-011-1782-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 07/12/2011] [Accepted: 07/28/2011] [Indexed: 11/24/2022] Open
Abstract
The functional consequence of long-term retinal detachment in the porcine model is examined by multifocal electroretinography (mfERG). Retinal detachment (RD) in humans leaves permanent visual impairment, despite anatomical successful reattachment surgery. To improve treatment, adjuvant pharmaceutical therapy is needed, and can only be tested in a suitable animal model. The porcine model is promising and the mfERG is well validated in this model. RD was induced in 18 pigs by vitrectomy and healon injection of various concentrations. Preoperatively and 6 weeks postoperatively eight animals were examined by mfERG. The major component P1 was analyzed statistically. Indirect ophthalmoscopy and bilateral color fundus photography (FP) were performed. Selected animals underwent high-resolution optical coherence tomography (OCT). Examination by ophthalmoscopy and FP showed that the RDs remained detached for the 6 weeks of follow-up. The P1 amplitude of the mfERG did not differ significantly between the detached areas, the surrounding attached areas, and the healthy eye (p = 0.25). Similarly, P1 implicit time did not differ between the areas (p = 0.85). The lack of functional consequences of long-term RD makes the porcine model unsuitable for examining adjuvant pharmaceutical RD treatment. Future studies should focus on foveated primates.
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Affiliation(s)
- Nina Fischer Sørensen
- Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark.
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Galdos M, Bayón A, Rodriguez FD, Micó C, Sharma SC, Vecino E. Morphology of retinal vessels in the optic disk in a Göttingen minipig experimental glaucoma model. Vet Ophthalmol 2011; 15 Suppl 1:36-46. [DOI: 10.1111/j.1463-5224.2011.00937.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Scott PA, Kaplan HJ, Sandell JH. Anatomical evidence of photoreceptor degeneration induced by iodoacetic acid in the porcine eye. Exp Eye Res 2011; 93:513-27. [PMID: 21740901 DOI: 10.1016/j.exer.2011.06.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/11/2011] [Accepted: 06/22/2011] [Indexed: 01/31/2023]
Abstract
Iodoacetic acid (IAA) induces photoreceptor (PR) degeneration in small animal models, however, eye size and anatomic differences detract from the usefulness of these models for studying retinal rescue strategies intended for humans. Porcine eyes are closer in size to human eyes and have a rich supply of rod and cones. This study investigated whether IAA also produced PR degeneration in the porcine retina, whether the damage was preferential for rods or cones, and whether IAA induced remodeling of the inner retina. Pigs were given a single i.v. injection of IAA and were euthanized 2-5 weeks later. Eyes were enucleated and immersed in fixative. Forty-six eyes were studied: Control (n = 13), and from pigs that had received the following IAA doses: 5.0 mg/kg (n = 7); 7.5 mg/kg (n = 10); 10.0 mg/kg (n = 6); 12.0 mg/kg (n = 6). Tissue was retrieved from four retinal locations: 8 mm and 2 mm above the dorsal margin of the optic disc, and 2 mm and 8 mm below the disc, and was processed for conventional histology, immunohistochemistry, and transmission electron microscopy. At 5.0 mg/kg IAA produced mild, variable cell loss, but remaining cells exhibited normal features. At doses above 5.0 mg/kg, a dose-dependent reduction was observed in the length of PR inner and outer segments, and in the number of PR nuclei. Specific labeling revealed a massive dropout of rod cell bodies with relative sparing of cone cell bodies, and electron microscopy revealed a reduction in the number of PR synaptic terminals. Mild dendritic retraction of rod bipolar cells and hypertrophy of Müller cell stalks was also observed, although the inner nuclear layer appeared intact. The porcine IAA model may be useful for developing and testing retinal rescue strategies for human diseases in which rods are more susceptible than cones, or are affected earlier in the disease process.
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Affiliation(s)
- Patrick A Scott
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA.
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Abstract
Although there appears to have been an increase in literature about the anatomy and physiology of the pig eye because of an expansion in its use as a model for research, there has been little written about the development of veterinary medicine in the area. Pig eyes share many similarities with human eyes, having a holangiotic retinal vasculature, no tapetum, cone photoreceptors in the outer retina, and a similar scleral thickness, rendering them valuable in comparative research. It must not be forgotten, however, that pigs are intelligent sentient animals which use vision as an important sense. Thus, diseases such as congenital cataracts, which impede vision, are important from the perspective of pig welfare. In addition, ocular lesions in this species, as with many others, can be a significant sign of systemic disease.
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Affiliation(s)
- Sheldon Middleton
- Acorn House Veterinary Surgery, Linnet Way, Brickhill, Bedford, MK41 7HN, UK.
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Pharmacokinetics of intravitreal glial cell line-derived neurotrophic factor: Experimental studies in pigs. Exp Eye Res 2010; 91:890-5. [DOI: 10.1016/j.exer.2010.09.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 09/15/2010] [Accepted: 09/21/2010] [Indexed: 11/21/2022]
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Mondy WL, Cameron D, Timmermans JP, De Clerck N, Sasov A, Casteleyn C, Piegl LA. Micro-CT of corrosion casts for use in the computer-aided design of microvasculature. Tissue Eng Part C Methods 2010; 15:729-38. [PMID: 19290799 DOI: 10.1089/ten.tec.2008.0583] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Two-dimensional micro-computed tomography (micro-CT) slices can be reconstructed into three-dimensional (3D) models that demonstrate capillary beds. This study focused on the acquisition of data necessary to create scaffolding that directly mimics the unique structural patterns of a microvascular tree system. The Microfil vascular contrasting method was compared to the Baston's methylmethacrylate corrosion casting (BMCC) method to determine which provided the most accurate and high-resolution results for 3D micro-CT reconstruction derived from the two-dimensional micro-CT slices of the capillary beds. It was determined that the BMCC, a method traditionally used in the scanning electron microscopic analysis of the microvasculature, was the best method for representing capillary lumina for micro-CT scanning. The removal of tissues from the BMCC cast resulted in samples that eliminated background material, thus increasing the X-ray contrast levels of the CT images. This provided for a more complete and more distinguishable high-resolution image of the represented capillary lumina. Images created with this BMCC method were reconstructed in a stereolithography file format as 3D mesh structure for later importing into computer-aided design (CAD) software. The resulting Bio-CAD, then, can be used to guide the more accurate fabrication of the microvascular scaffolding and then serve as the framework for tissue engineering of microvascular structures. Results from this study clearly indicated that the BMCC method is superior to the Microfil method for accurate and complete high-resolution imaging of capillary beds.
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Affiliation(s)
- William Lafayette Mondy
- Department of Chemical and Biomedical Engineering, University of South Florida , Tampa, FL 33620, USA
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Development of an image-based network model of retinal vasculature. Ann Biomed Eng 2010; 38:1566-85. [PMID: 20135352 DOI: 10.1007/s10439-010-9942-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 01/19/2010] [Indexed: 10/19/2022]
Abstract
The paper presents an image-based network model of retinal vasculature taking account of the 3D vascular distribution of the retina. Mouse retinas were prepared using flat-mount technique and vascular images were obtained using confocal microscopy. The vascular morphometric information obtained from confocal images was used for the model development. The network model developed directly represents the vascular geometry of all the large vessels of the arteriolar and venular trees and models the capillaries using uniformly distributed meshes. The vasculatures in different layers of the retina, namely the superficial, intermediate, and deep layer, were modeled separately in the network and were linked through connecting vessels. The branching data of the vasculatures was recorded using the method of connectivity matrix of network (the graph theory). Such an approach is able to take into account the detailed vasculature of individual retinas concerned. Using the network model developed, a circulation analysis based on Poiseuille's equation was carried out. The investigations produced predictions of spatial distribution of the pressure, flow, and wall shear stress in the entire retinal vasculature. The method developed can be used as a tool for continuous monitoring of the retinal circulation for clinical assessments as well as experimental studies.
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Yu DY, Cringle SJ, Su EN, Yu PK. Sphincter Activity in Retinal Arterioles Feeding the Deeper Capillary Layer in Pig. Curr Eye Res 2009; 30:781-7. [PMID: 16146924 DOI: 10.1080/02713680590968448] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE To determine whether a sphincter-like control point is present in 90 degrees branches of the retinal vasculature. Such a control point could selectively control retinal blood flow to the deeper capillary layers. METHODS A microperfusion system was used in which porcine retinal arteries with intact branches were cannulated and perfused intraluminally at physiological flow rates. The vasoactive response of the proximal and distal regions of either 90 degrees -or Y-type branches to intraluminal potassium (124 mM) were monitored simultaneously in real-time. RESULTS The proximal region of the 90 degrees branches demonstrated a localized vasoconstriction when compared to the more distal region (p < 0.0001). In contrast, the Y branches contracted evenly along their length. CONCLUSIONS The localized vasoactivity near the branch point of the 90 degrees -type branches may explain previous observations of so-called sphincter-like activity in these vessels. These sphincters may selectively regulate blood flow to the deeper retinal capillary layer.
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Affiliation(s)
- Dao-Yi Yu
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, The University of Western Australia, Nedlands, Perth, Australia.
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Abstract
The purpose of the present thesis was to develop an animal model of CNV in order to study the early formation of CNV and to test the effects of an anti-angiogenic treatment. Porcine eyes were chosen as a substrate for CNV induction, since they are similar to human eyes in terms of both macroscopic and microscopic morphology. However, a major difference is that pigs lack a fovea; instead they have a visual streak, with a relatively stable and high concentration of cones. By surgical perforation of Bruch's membrane we were able to induce formation of CNV membranes. The morphology and cellular composition of these membranes varied with the surgical technique employed. When RPE cells were locally removed at the time of perforation, the resulting CNV was thinner, contained fewer blood vessels and was less prone to leak on fluorescein angiography than when RPE cells were left intact at induction. The neuroretina overlying the perforation site was not damaged by any of the surgical techniques, thus allowing the subsequent retinal damage to be ascribed to the actual process of CNV formation. Using this animal model allowed us to directly map histological findings onto fluorescein angiograms and thereby perform meaningful correlations between histopathologic and photographic features. Such correlations have been hampered in human subjects, since human eyes are not enucleated as a consequence of CNV and are therefore only available for post-mortem studies. In such studies there often is a considerable time-gap between the death of the patient and the latest available fluorescein angiogram, thereby allowing macular pathology to evolve in the interim. Histological examination of the porcine membranes demonstrated that they were composed of RPE cells, glial cells, macrophages, endothelial cells, collagen and smooth muscle fibres, which are the same cellular and fibrillar elements that dominate human CNV membranes. The porcine model was applied to test the effects, in a randomized and masked fashion, of intravitreally injected bevacizumab. Bevacizumab, a pan VEGF A antibody, was found to reduce both the proliferation of endothelial cells in CNV membranes and the propensity to leak in fluorescein angiograms. Immunohistochemically, bevacizumab was detected in the inner limiting membrane, in retinal blood vessels and binding uniformly to the entire CNV membrane without any cellular predisposition. Based on the above findings we believe that the porcine CNV model shows a bearing to human disease and therefore might be used as a tool to obtain improved treatments for this debilitating condition.
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Affiliation(s)
- Nathan Lassota
- Faculty of Health Sciences, University of Copenhagen, Denmark
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42
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Voss Kyhn MC. Multifocal electroretinography (mfERG) in porcine eyes: establishment, sensitivity and functional implications of induced retinal lesions. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1600-0420.2007.00952.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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43
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Maaijwee KJM, van Meurs JC, Kirchhof B, Mooij CM, Fischer JH, Mackiewicz J, Kobuch K, Joussen AM. Histological evidence for revascularisation of an autologous retinal pigment epithelium--choroid graft in the pig. Br J Ophthalmol 2007; 91:546-50. [PMID: 16987900 PMCID: PMC1994759 DOI: 10.1136/bjo.2006.103259] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Translocation of a free autologous graft consisting of retinal pigment epithelium (RPE), Bruch's membrane, choriocapillaris and choroid in patients with exudative age-related macular degeneration is currently being evaluated in clinical practice. Angiographic studies in these patients suggest that their grafts become revascularised. AIM To investigate the histological evidence of revascularisation of the graft in a porcine model. METHODS In 11 pigs (11 eyes), an RPE-choroid graft was translocated from the mid-periphery to an intact or an intentionally damaged RPE and Bruch's membrane at the recipient site. The eyes were enucleated 1 week or 3 months after surgery. Tissue sections were evaluated using immunohistochemistry. RESULTS Bridging vessels between recipient layer and graft were identified from 1 week to 3 months after surgery. This reconnection occurred regardless of whether the Bruch's membrane of the recipient site was left intact or intentionally damaged at the time of transplantation. The vasculature of the graft appeared open and perfused. Vessels with transcapillary pillars and conglomerates of small new vessels were present in the graft. CONCLUSIONS This study showed histological evidence for revascularisation by angiogenesis of a free autologous RPE-choroid graft.
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Affiliation(s)
- Kristel J M Maaijwee
- Department of Vitreoretinal Surgery, Center of Ophthalmology, University of Cologne, Germany
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Ninomiya H, Inomata T. Microvascular anatomy of the pig eye: scanning electron microscopy of vascular corrosion casts. J Vet Med Sci 2007; 68:1149-54. [PMID: 17146170 DOI: 10.1292/jvms.68.1149] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The microvasculature of the eye of 10 pigs was investigated using scanning electron micrographs of corrosion casts. The ciliary body, iris and bulbar conjunctiva were supplied by the iridociliary ring artery via the long posterior ciliary artery. Capillaries of the ciliary process were of large diameter (23.2-27.5 microm) with an irregular bore, forming a thoroughfare channel draining blood in the ciliary arterioles into the pars plana venous vessels. Arterioles and venules in the iris exhibited a zigzag or spiral features. The third palpebra was supplied by the anterior ciliary artery. The capillary bed of the third palpebra was dense and was formed by many rows of fine hair-pin loops. Capillaries in the bulbar conjunctiva formed a sparse network disposing approximately parallel to the epithelium and formed a well-developed venous plexus, draining into the vortex veins. Retinal arterioles formed a slender and long course to capillaries. Retinal capillaries were extremely thin (3.0-4.0 microm in diameter). The choroid was supplied by the short posterior ciliary arteries. Choroidal arterioles exhibited a thick and short course to the choriocapillaris. The choriocapillaris was flat and sinusoid-like (8.9-13.9 microm in diameter), forming a dense sheet-like network. Blood from the choroid emptied into the episcleral vein via the vortex vein. Blood from the retina was drained by the posterior ciliary veins. The functional significance of this vascular architecture was discussed.
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Affiliation(s)
- Hiroyoshi Ninomiya
- Department of Laboratory Animal Science, Azabu University, Sagamihara, Japan
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45
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Retinal Pigment Epithelium and Photoreceptor Transplantation Frontiers. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50159-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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46
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Townsend R, Cringle SJ, Morgan WH, Chauhan BC, Yu DY. Confocal laser Doppler flowmeter measurements in a controlled flow environment in an isolated perfused eye. Exp Eye Res 2006; 82:65-73. [PMID: 15993409 DOI: 10.1016/j.exer.2005.05.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Revised: 04/07/2005] [Accepted: 05/25/2005] [Indexed: 11/16/2022]
Abstract
The aim of this study was to improve our ability to interpret and validate Heidelberg Retina Flowmeter (HRF) flow images by recording flow measurements from specific regions of the retinal vasculature by taking advantage of the ability to precisely regulate perfusion flow in an isolated eye preparation. The retinal vasculature in 16 isolated perfused pig eyes was perfused with a 50%/50% Krebs/RBC solution at known flow rates ranging from 0 to 300 microl min(-1). At each flow rate, HRF images were obtained at a location approximately two disc diameters from the disc. After HRF image acquisition, the retinal vasculature was perfused with fluorescein isothiocyanate for fluorescence microscopy. Using the standard HRF software and a 10 x 10pixel measurement window, flow rates were measured from a retinal artery, vein, arteriole, venule, and the retinal capillary bed and a capillary-free-zone. The relationship between HRF measured flow and perfusion flow in the different measurement locations was determined. At zero perfusion flow the measured HRF flow was consistently greater than zero ( approximately 170 arbitrary units (AU)), and not significantly different at each measurement location except for the retinal vein, which had a significantly higher HRF flow value ( approximately 230AU). At higher perfusion flow rates the flow signal from the larger vascular elements (arteries and veins) increased rapidly thereafter to reach several thousand AU at a total perfusate flow of 50 microlmin(-1) and increased less rapidly at higher flow rates. In arterioles, the HRF flow was more linear over a broader range of perfusate flow rates but the peak flow signal was an order of magnitude smaller than that from the retinal artery. Both the linearity and magnitude of the flow signal in venules was less than that in arterioles. In capillary areas and in the capillary free zone, the HRF flow showed only a very weak relationship to perfusion flow when compared to the background noise. The choice of location for HRF flow analysis greatly influences the ability of the technique to measure changes in retinal blood flow. The major arteries and veins provide the strongest signal and greatest signal to noise ratio. However, the retinal arterioles produce an HRF signal that is more linear over a wider range of perfusate flow rates.
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Affiliation(s)
- R Townsend
- Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Perth, Australia
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Shahidullah M, Yap M, To CH. Cyclic GMP, sodium nitroprusside and sodium azide reduce aqueous humour formation in the isolated arterially perfused pig eye. Br J Pharmacol 2005; 145:84-92. [PMID: 15711584 PMCID: PMC1576120 DOI: 10.1038/sj.bjp.0706156] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The effect of nitric oxide (NO) on aqueous humour formation (AHF) and intraocular pressure (IOP) was studied using NO donors, sodium azide (AZ) and sodium nitroprusside (SNP). Using the porcine arterially perfused eye preparation, drug effects on AHF and IOP were measured by fluorescein dilution and manometry, respectively. Perfusion pressure of the ocular vasculature was also monitored using digital pressure transducer and pen recorder. L-Arginine (1.0 mM), a precursor of NO, but not D-arginine (1.0 mM), the inactive analogue, produced a significant reduction in AHF (28.5%) and IOP (21.1%). L-NAME (L-nitro-L-arginine) (10-100 microM), an NO synthase inhibitor, had no effect on AHF and IOP. However, L-NAME (100 microM) completely reversed L-arginine's effect. AZ and SNP reduced the AHF and IOP dose-dependently. AZ at 100 nM, 1 and 10 microM reduced AHF by 26.0, 39.7 and 51.7% and IOP by 10.8, 17.3 and 24.0%, respectively. SNP at 1, 10 and 100 microM reduced the AHF by 6.0, 24.2 and 35.4% and IOP by 3.5, 9.5 and 15.5%, respectively. 8-pCPT-cGMP (8-para-chlorophenyl-thioguanosine-3',5'-cyclic guanosine monophosphate, 10 microM), a cGMP analogue, also reduced the AHF (34.9%) and IOP (15.9%). The effects of AZ and SNP on the AHF and IOP were blocked by a soluble guanylate cyclase inhibitor ODQ (10 microM), whereas ODQ alone or combined with 8-pCPT-cGMP had no effect on the AHF and IOP. None of the drugs had any significant effect on ocular vasculature. The reduction of the AHF and IOP in the arterially perfused pig eye by nitrovasodilators is likely to involve the NO-cGMP pathway.
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Affiliation(s)
- Mohammad Shahidullah
- The Laboratory of Experimental Optometry, Department of Optometry and Radiography, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
- Author for correspondence:
| | - Maurice Yap
- The Laboratory of Experimental Optometry, Department of Optometry and Radiography, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Chi-ho To
- The Laboratory of Experimental Optometry, Department of Optometry and Radiography, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
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Hendrickson A, Hicks D. Distribution and density of medium- and short-wavelength selective cones in the domestic pig retina. Exp Eye Res 2002; 74:435-44. [PMID: 12076087 DOI: 10.1006/exer.2002.1181] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The topography of medium (M)- and short (S)-wavelength sensitive cone photoreceptors was studied in the domestic pig retina. Antisera specific for M or S opsin as well as cone photoreceptor proteins arrestin and alpha-transducin were used to label cone types. Retinal wholemounts and their blood vessel patterns were drawn and specific regions removed. The wholemounts were immunocytochemically labelled to detect both M and S cones, and the specific regions labelled to detect S cones. Cones were counted in a 1 mm grid pattern, using the drawings as a guide. Pig retina has a high cone density retinal streak extending across the retina covering the optic disc (OD) and horizontal meridian. Densities in the streak are 20,000-35,000 mm(-2). Two higher peaks occur in the streak, one in temporal retina near the OD (39,000 mm(-2)) and the other in nasal retina 5-7 mm from the OD (40,500 mm(-2)). The lowest cone density is in far peripheral inferior retina (7000 mm(-2)). The total number of cones in pig retina is 17-20 million. Both types of cones are found throughout the retina, with S cone percentages ranging from 7.4 to 17.5% in no consistent topographical pattern. S cones have an irregular local distribution which can vary from a regular hexagonal pattern to small clusters of adjacent S cones to small areas lacking S cones. Double-label immunocytochemistry found that virtually all S cone outer segments (OS) contain some M opsin. M cone OS do not label at detectible levels for S opsin. Domestic pig retina is widely available, large, has a high cone density and has two types of cones. This tissue should be an excellent source for biochemical analysis of cone proteins, and for in vitro approaches to understanding cone survival factors.
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Affiliation(s)
- Anita Hendrickson
- Department of Biological Structure, University of Washington, Seattle, WA, 98195, USA.
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Brooks D, Arellano E, Kubilis P, Komaromy A. Histomorphometry of the porcine scleral lamina cribrosa surface. Vet Ophthalmol 2001; 1:129-135. [PMID: 11397222 DOI: 10.1046/j.1463-5224.1998.00029.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The lamina cribrosa surface of the pig was examined using trypsin digestion, scanning electron microscopy, and computerized image analysis. Six normal eyes from healthy pigs were studied. The total intralaminar scan area, total number of laminar pores, median individual laminar pore areas, median individual pore form factors, and mean pore density were determined for the dorsal, ventral, nasal and temporal hemicircles, the dorsal-nasal, dorsal-temporal, ventral-nasal, and ventral-temporal quadrants, and their central and peripheral subdivisions. The mean (+/- SD) total intralaminar scan area was 8.29 +/- 1.54 mm2. The mean (+/- SD) total laminar pore count was 517 +/- 73 pores. The mean pore count was significantly larger in the ventral than the dorsal hemicircle (292 +/- 39 vs. 225 +/- 38 pores, respectively; P = 0.001), and significantly greater in the periphery compared to the center (388 +/- 58 vs. 129 +/- 27 pores, respectively; P = 0.0001). The overall mean (+/- SD) pore density was 67 +/- 7 pores mm-2. Mean pore density was significantly greater in the ventral than the dorsal hemicircle (70 +/- 8 vs. 64 +/- 6 pores mm-2, respectively; P = 0.019), and significantly greater in the center compared to the periphery (75 +/- 9 vs. 60 +/- 8 pores mm-2, respectively; P = 0.020). The mean (+/- SD) median individual pore area was 3752 +/- 572 &mgr;m2. The mean (+/- SD) median pore form factor was 0.680 +/- 0.035. No significant regional differences were found in mean median pore form factor or mean median individual pore areas. The intralaminar optic nerve of pigs is 55.1% non-neural connective and vascular tissue. A pigmented ventral fascial groove in the scleral lamina cribrosa appears unique to the porcine lamina cribrosa, and may be a vestige of the embryonic optic fissure.
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Affiliation(s)
- D.E. Brooks
- University of Florida, College of Veterinary Medicine, PO Box 100126, Gainesville, FL 32610, USA; University of Florida, College of Veterinary Medicine, PO Box 100126, Gainesville, FL 32610, USA; University of Florida, College of Veterinary Medicine, PO Box 100126, Gainesville, FL 32610, USA; University of Florida, College of Veterinary Medicine, PO Box 100126, Gainesville, FL 32610, USA
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50
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Chandler M, Smith P, Samuelson D, MacKay E. Photoreceptor density of the domestic pig retina. Vet Ophthalmol 2001; 2:179-184. [PMID: 11397262 DOI: 10.1046/j.1463-5224.1999.00077.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The spatial distribution and densities of photoreceptors in seven whole-mounted porcine retinas were studied and maps illustrating photoreceptor topography were constructed. Total photoreceptor densities ranged from to 83 000 to 200 000 cells/mm2, with a mean of 138 500 cells/mm2. Cone densities ranged from 39 000 (area centralis) to 8500 cones/mm2 (peripherally), with a mean of 16 400 cones/mm2. Rod:cone ratios ranged from 3:1 centrally to 16:1 peripherally, with a mean ratio of 8:1. Averaged photoreceptor densities are greatest (166 000 cells/mm2) within the central inferior retina, and regional differences in rod:cone ratios were found. Cone densities are increased in a broad region dorsal to the optic disk, extending both nasally and temporally. This region is believed to represent the area centralis. Cone densities gradually decrease and taper towards the periphery and inferior retina as rod:cone ratios increase. In addition to the many anatomic and ultrastructural similarities to the human eye, this study illustrates similarities within the photoreceptor mosaic of these two species and supports the use of the pig retina as a model for human/animal research.
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Affiliation(s)
- M.J. Chandler
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA; Animal Eye Care, Fremont, CA 94539, USA; Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA; Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
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