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Parmann R, Tsang SH, Sparrow JR. Primary versus Secondary Elevations in Fundus Autofluorescence. Int J Mol Sci 2023; 24:12327. [PMID: 37569703 PMCID: PMC10419315 DOI: 10.3390/ijms241512327] [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: 06/08/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
The method of quantitative fundus autofluorescence (qAF) can be used to assess the levels of bisretinoids in retinal pigment epithelium (RPE) cells so as to aid the interpretation and management of a variety of retinal conditions. In this review, we focused on seven retinal diseases to highlight the possible pathways to increased fundus autofluorescence. ABCA4- and RDH12-associated diseases benefit from known mechanisms whereby gene malfunctioning leads to elevated bisretinoid levels in RPE cells. On the other hand, peripherin2/RDS-associated disease (PRPH2/RDS), retinitis pigmentosa (RP), central serous chorioretinopathy (CSC), acute zonal occult outer retinopathy (AZOOR), and ceramide kinase like (CERKL)-associated retinal degeneration all express abnormally high fundus autofluorescence levels without a demonstrated pathophysiological pathway for bisretinoid elevation. We suggest that, while a known link from gene mutation to increased production of bisretinoids (as in ABCA4- and RDH12-associated diseases) causes primary elevation in fundus autofluorescence, a secondary autofluorescence elevation also exists, where an impairment and degeneration of photoreceptor cells by various causes leads to an increase in bisretinoid levels in RPE cells.
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Affiliation(s)
- Rait Parmann
- Departments of Ophthalmology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
| | - Stephen H. Tsang
- Departments of Ophthalmology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
- Departments of Pathology and Cell Biology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
| | - Janet R. Sparrow
- Departments of Ophthalmology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
- Departments of Pathology and Cell Biology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
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Birtel J, Bauer T, Pauleikhoff L, Rüber T, Gliem M, Charbel Issa P. Fundus autofluorescence imaging using red excitation light. Sci Rep 2023; 13:9916. [PMID: 37336979 DOI: 10.1038/s41598-023-36217-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 05/31/2023] [Indexed: 06/21/2023] Open
Abstract
Retinal disease accounts significantly for visual impairment and blindness. An important role in the pathophysiology of retinal disease and aging is attributed to lipofuscin, a complex of fluorescent metabolites. Fundus autofluorescence (AF) imaging allows non-invasive mapping of lipofuscin and is a key technology to diagnose and monitor retinal disease. However, currently used short-wavelength (SW) excitation light has several limitations, including glare and discomfort during image acquisition, reduced image quality in case of lens opacities, limited visualization of the central retina, and potential retinal light toxicity. Here, we establish a novel imaging modality which uses red excitation light (R-AF) and overcomes these drawbacks. R-AF images are high-quality, high-contrast fundus images and image interpretation may build on clinical experience due to similar appearance of pathology as on SW-AF images. Additionally, R-AF images may uncover disease features that previously remained undetected. The R-AF signal increases with higher abundance of lipofuscin and does not depend on photopigment bleaching or on the amount of macular pigment. Improved patient comfort, limited effect of cataract on image quality, and lack of safety concerns qualify R-AF for routine clinical monitoring, e.g. for patients with age-related macular degeneration, Stargardt disease, or for quantitative analysis of AF signal intensity.
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Affiliation(s)
- Johannes Birtel
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias Bauer
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Laurenz Pauleikhoff
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Theodor Rüber
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Martin Gliem
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Peter Charbel Issa
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 9DU, UK.
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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Cronin T, Croyal M, Provost N, Ducloyer JB, Mendes-Madeira A, Libeau L, Morival C, Toublanc E, Audrain C, Isiegas C, Pichard V, Adjali O. Effect of retinol dehydrogenase gene transfer in a novel rat model of Stargardt disease. FASEB J 2021; 35:e21934. [PMID: 34599778 DOI: 10.1096/fj.202002525rrr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 08/25/2021] [Accepted: 09/03/2021] [Indexed: 11/11/2022]
Abstract
Dysfunction of the ATPase-binding Cassette Transporter protein (ABCA4) can lead to early onset macular degeneration, in particular to Stargardt disease. To enable translational research into this form of blindness, we evaluated the effect of Cas9-induced disruptions of the ABCA4 gene to potentially generate new transgenic rat models of the disease. We show that deletion of the short exon preceding the second nucleotide-binding domain is sufficient to drastically knock down protein levels and results in accumulation of retinoid dimers similar to that associated with Stargardt disease. Overexpression of the retinol dehydrogenase enzymes RDH8 and RDH12 can to a limited extent offset the increase in the bisretinoid levels in the Abca4Ex42-/ - KO rats possibly by restricting the time window in which retinal can dimerize before being reduced to retinol. However, in vivo imaging shows that overexpression of RDH8 can induce retinal degeneration. This may be due to the depletion in the outer segment of the cofactor NADPH, needed for RDH function. The translational potential of RDH therapy as well as other Stargardt disease therapies can be tested using the Abca4 knockdown rat model.
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Affiliation(s)
- T Cronin
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | | | - N Provost
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - J B Ducloyer
- Department of Ophthalmology, University Hospital of Nantes, CHU de Nantes, Nantes, France
| | - A Mendes-Madeira
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - L Libeau
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - C Morival
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - E Toublanc
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - C Audrain
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - C Isiegas
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - V Pichard
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - O Adjali
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
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Yusuf IH, McClements ME, MacLaren RE, Charbel Issa P. Deep phenotyping of the Cdhr1 -/- mouse validates its use in pre-clinical studies for human CDHR1-associated retinal degeneration. Exp Eye Res 2021; 208:108603. [PMID: 33964272 DOI: 10.1016/j.exer.2021.108603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/01/2021] [Accepted: 04/21/2021] [Indexed: 12/30/2022]
Abstract
PURPOSE To validate the Cdhr1-/- mouse as a model for human CDHR1-associated retinal degeneration, which may present as cone-rod dystrophy or geographic atrophy. METHODS Deep phenotyping of Cdhr1-/-(n = 56) and C57BL6J wildtype control mice (n = 45) was undertaken using in vivo multimodal retinal imaging and dark- and light-adapted electroretinography (ERG) over 15 months to evaluate rod- and cone-photoreceptor responses and retinal morphology. RESULTS Cdhr1-/- retinas exhibited outer retinal thinning on optical coherence tomography (OCT) at 1-month versus C57BL6J (mean 14.6% reduction; P < 0.0001), with progressive degeneration to 15 months. The OCT layer representing photoreceptor outer segments was more significantly shortened in Cdhr1-/- eyes at 1 month (mean 33.7% reduction; P < 0.0001), remained stable to 3 months and was not identifiable at later timepoints. Outer retinal thinning was more pronounced at inferior versus superior retinal locations in Cdhr1-/- eyes (P < 0.002 at 3-9 months). Dark-adapted ERG identified severe functional deficits in Cdhr1-/- mice at 1 month of age versus C57BL6J (mean 62% reduction) that continued to decline to 15 months (P < 0.0001). Light-adapted flicker identified severe deficits in cone function at 1 month (mean 70% reduction), with improved function to 3 months followed by progressive decline (P < 0.0001). CONCLUSIONS The Cdhr1-/- mouse exhibits structural and functional evidence of progressive outer retinal degeneration at a slow rate. Early functional deficits affecting both rod and cone photoreceptors in the context of relatively mild structural changes reflect the human phenotype. This study validates the use of the Cdhr1-/- mouse for the pre-clinical evaluation of therapeutics for human CDHR1-associated retinal degeneration.
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Affiliation(s)
- Imran H Yusuf
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford, OX3 9DU, UK; Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Headley Way, Oxford, OX3 9DU, UK
| | - Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford, OX3 9DU, UK; Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Headley Way, Oxford, OX3 9DU, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford, OX3 9DU, UK; Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Headley Way, Oxford, OX3 9DU, UK
| | - Peter Charbel Issa
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford, OX3 9DU, UK; Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Headley Way, Oxford, OX3 9DU, UK.
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Cao KJ, Kim JH, Kroeger H, Gaffney PM, Lin JH, Sigurdson CJ, Yang J. ARCAM-1 Facilitates Fluorescence Detection of Amyloid-Containing Deposits in the Retina. Transl Vis Sci Technol 2021; 10:5. [PMID: 34096989 PMCID: PMC8185402 DOI: 10.1167/tvst.10.7.5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Purpose To investigate the use of an amyloid-targeting fluorescent probe, ARCAM-1, to identify amyloid-containing deposits in the retina of a transgenic mouse model of Alzheimer's disease (AD) and in human postmortem AD patients. Methods Aged APP/PS1 transgenic AD and wild-type (WT) mice were given an intraperitoneal (IP) injection of ARCAM-1 and their retinas imaged in vivo using a fluorescence ophthalmoscope. Eyes were enucleated and dissected for ex vivo inspection of retinal amyloid deposits. Additionally, formalin-fixed eyes from human AD and control patients were dissected, and the retinas were stained using ARCAM-1 or with an anti-amyloid-β antibody. Confocal microscopy was used to image amyloid-containing deposits stained with ARCAM-1 or with immunostaining. Results Four out of eight APP/PS1 mice showed the presence of amyloid aggregates in the retina during antemortem imaging. Retinas from three human AD patients stained with ARCAM-1 showed an apparent increased density of fluorescently labeled amyloid-containing deposits compared to the retinas from two healthy, cognitively normal (CN) patients. Immunolabeling confirmed the presence of amyloid deposits in both the retinal neuronal layers and in retinal vasculature. Conclusions ARCAM-1 facilitates antemortem detection of amyloid aggregates in the retina of a mouse model for AD, and postmortem detection of amyloid-containing deposits in human retinal tissues from AD patients. These results support the hypothesis of AD pathology manifesting in the eye and highlight a novel area for fluorophore development for the optical detection of retinal amyloid in AD patients. Translational Relevance This paper represents an initial examination for potential translation of an amyloid-targeting fluorescent probe to a retinal imaging agent for aiding in the diagnosis of Alzheimer's disease.
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Affiliation(s)
- Kevin J Cao
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - John H Kim
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Heike Kroeger
- Departments of Pathology and Medicine, University of California, San Diego, La Jolla, CA, USA.,Department of Cellular Biology, Franklin College of Arts and Sciences, University of Georgia, Athens, GA, USA
| | - Patricia M Gaffney
- Departments of Pathology and Medicine, University of California, San Diego, La Jolla, CA, USA.,Department of Disease Investigations, San Diego Zoo Wildlife Alliance, San Diego, CA, USA
| | - Jonathan H Lin
- Departments of Pathology and Medicine, University of California, San Diego, La Jolla, CA, USA.,Departments of Pathology and Byers Eye Institute, Stanford University, Palo Alto, CA, USA
| | - Christina J Sigurdson
- Departments of Pathology and Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jerry Yang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
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Pfau M, Jolly JK, Wu Z, Denniss J, Lad EM, Guymer RH, Fleckenstein M, Holz FG, Schmitz-Valckenberg S. Fundus-controlled perimetry (microperimetry): Application as outcome measure in clinical trials. Prog Retin Eye Res 2020; 82:100907. [PMID: 33022378 DOI: 10.1016/j.preteyeres.2020.100907] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/20/2020] [Accepted: 09/23/2020] [Indexed: 02/06/2023]
Abstract
Fundus-controlled perimetry (FCP, also called 'microperimetry') allows for spatially-resolved mapping of visual sensitivity and measurement of fixation stability, both in clinical practice as well as research. The accurate spatial characterization of visual function enabled by FCP can provide insightful information about disease severity and progression not reflected by best-corrected visual acuity in a large range of disorders. This is especially important for monitoring of retinal diseases that initially spare the central retina in earlier disease stages. Improved intra- and inter-session retest-variability through fundus-tracking and precise point-wise follow-up examinations even in patients with unstable fixation represent key advantages of these technique. The design of disease-specific test patterns and protocols reduces the burden of extensive and time-consuming FCP testing, permitting a more meaningful and focused application. Recent developments also allow for photoreceptor-specific testing through implementation of dark-adapted chromatic and photopic testing. A detailed understanding of the variety of available devices and test settings is a key prerequisite for the design and optimization of FCP protocols in future natural history studies and clinical trials. Accordingly, this review describes the theoretical and technical background of FCP, its prior application in clinical and research settings, data that qualify the application of FCP as an outcome measure in clinical trials as well as ongoing and future developments.
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Affiliation(s)
- Maximilian Pfau
- Department of Ophthalmology, University of Bonn, Bonn, Germany; Department of Biomedical Data Science, Stanford University, Stanford, USA
| | - Jasleen Kaur Jolly
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Zhichao Wu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Eleonora M Lad
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Steffen Schmitz-Valckenberg
- Department of Ophthalmology, University of Bonn, Bonn, Germany; John A. Moran Eye Center, University of Utah, USA.
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Hassall MM, McClements ME, Barnard AR, Patrício MI, Aslam SA, Maclaren RE. Analysis of Early Cone Dysfunction in an In Vivo Model of Rod-Cone Dystrophy. Int J Mol Sci 2020; 21:ijms21176055. [PMID: 32842706 PMCID: PMC7503557 DOI: 10.3390/ijms21176055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 08/20/2020] [Indexed: 01/12/2023] Open
Abstract
Retinitis pigmentosa (RP) is a generic term for a group of genetic diseases characterized by loss of rod and cone photoreceptor cells. Although the genetic causes of RP frequently only affect the rod photoreceptor cells, cone photoreceptors become stressed in the absence of rods and undergo a secondary degeneration. Changes in the gene expression profile of cone photoreceptor cells are likely to occur prior to observable physiological changes. To this end, we sought to achieve greater understanding of the changes in cone photoreceptor cells early in the degeneration process of the Rho−/− mouse model. To account for gene expression changes attributed to loss of cone photoreceptor cells, we normalized PCR in the remaining number of cones to a cone cell reporter (OPN1-GFP). Gene expression profiles of key components involved in the cone phototransduction cascade were correlated with tests of retinal cone function prior to cell loss. A significant downregulation of the photoreceptor transcription factor Crx was observed, which preceded a significant downregulation in cone opsin transcripts that coincided with declining cone function. Our data add to the growing understanding of molecular changes that occur prior to cone dysfunction in a model of rod-cone dystrophy. It is of interest that gene supplementation of CRX by adeno-associated viral vector delivery prior to cone cell loss did not prevent cone photoreceptor degeneration in this mouse model.
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Affiliation(s)
- Mark M. Hassall
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; (M.E.M.); (A.R.B.); (M.I.P.); (S.A.A.); (R.E.M.)
- Correspondence: ; Tel.: +61-426-732-991
| | - Michelle E. McClements
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; (M.E.M.); (A.R.B.); (M.I.P.); (S.A.A.); (R.E.M.)
| | - Alun R. Barnard
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; (M.E.M.); (A.R.B.); (M.I.P.); (S.A.A.); (R.E.M.)
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Maria I. Patrício
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; (M.E.M.); (A.R.B.); (M.I.P.); (S.A.A.); (R.E.M.)
| | - Sher A. Aslam
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; (M.E.M.); (A.R.B.); (M.I.P.); (S.A.A.); (R.E.M.)
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Robert E. Maclaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; (M.E.M.); (A.R.B.); (M.I.P.); (S.A.A.); (R.E.M.)
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
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Fang Y, Tschulakow A, Taubitz T, Illing B, Biesemeier A, Julien-Schraermeyer S, Radu RA, Jiang Z, Schraermeyer U. Fundus autofluorescence, spectral-domain optical coherence tomography, and histology correlations in a Stargardt disease mouse model. FASEB J 2020; 34:3693-3714. [PMID: 31989709 DOI: 10.1096/fj.201901784rr] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 12/17/2019] [Accepted: 12/17/2019] [Indexed: 01/09/2023]
Abstract
Stargardt disease (STGD1), known as inherited retinal dystrophy, is caused by ABCA4 mutations. The pigmented Abca4-/- mouse strain only reflects the early stage of STGD1 since it is devoid of retinal degeneration. This blue light-illuminated pigmented Abca4-/- mouse model presented retinal pigment epithelium (RPE) and photoreceptor degeneration which was similar to the advanced STGD1 phenotype. In contrast, wild-type mice showed no RPE degeneration after blue light illumination. In Abca4-/- mice, the acute blue light diminished the mean autofluorescence (AF) intensity in both fundus short-wavelength autofluorescence (SW-AF) and near-infrared autofluorescence (NIR-AF) modalities correlating with reduced levels of bisretinoid-fluorophores. Blue light-induced RPE cellular damage preceded the photoreceptors loss. In late-stage STGD1-like patient and blue light-illuminated Abca4-/- mice, lipofuscin and melanolipofuscin granules were found to contribute to NIR-AF, indicated by the colocalization of lipofuscin-AF and NIR-AF under the fluorescence microscope. In this mouse model, the correlation between in vivo and ex vivo assessments revealed histological characteristics of fundus AF abnormalities. The flecks which are hyper AF in both SW-AF and NIR-AF corresponded to the subretinal macrophages fully packed with pigment granules (lipofuscin, melanin, and melanolipofuscin). This mouse model, which has the phenotype of advanced STGD1, is important to understand the histopathology of Stargardt disease.
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Affiliation(s)
- Yuan Fang
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Alexander Tschulakow
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Preclinical Drug Assessment, STZ Ocutox, Hechingen, Germany
| | - Tatjana Taubitz
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Barbara Illing
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Antje Biesemeier
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Sylvie Julien-Schraermeyer
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Preclinical Drug Assessment, STZ Ocutox, Hechingen, Germany
| | - Roxana A Radu
- UCLA Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Zhichun Jiang
- UCLA Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Ulrich Schraermeyer
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Preclinical Drug Assessment, STZ Ocutox, Hechingen, Germany
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9
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Barnea-Cramer AO, Singh M, Fischer D, De Silva S, McClements ME, Barnard AR, MacLaren RE. Repair of Retinal Degeneration following Ex Vivo Minicircle DNA Gene Therapy and Transplantation of Corrected Photoreceptor Progenitors. Mol Ther 2020; 28:830-844. [PMID: 32027843 DOI: 10.1016/j.ymthe.2020.01.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/07/2020] [Accepted: 01/07/2020] [Indexed: 10/25/2022] Open
Abstract
The authors describe retinal reconstruction and restoration of visual function in heritably blind mice missing the rhodopsin gene using a novel method of ex vivo gene therapy and cell transplantation. Photoreceptor precursors with the same chromosomal genetic mutation were treated ex vivo using minicircle DNA, a non-viral technique that does not present the packaging limitations of adeno-associated virus (AAV) vectors. Following transplantation, genetically modified cells reconstructed a functional retina and supported vision in blind mice harboring the same founder gene mutation. Gene delivery by minicircles showed comparable long-term efficiency to AAV in delivering the missing gene, representing the first non-viral system for robust treatment of photoreceptors. This important proof-of-concept finding provides an innovative convergence of cell and gene therapies for the treatment of hereditary neurodegenerative disease and may be applied in future studies toward ex vivo correction of patient-specific cells to provide an autologous source of tissue to replace lost photoreceptors in inherited retinal blindness. This is the first report using minicircles in photoreceptor progenitors and the first to transplant corrected photoreceptor precursors to restore vision in blind animals.
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Affiliation(s)
| | - Mandeep Singh
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK; Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Dominik Fischer
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK; University Eye Hospital and Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Samantha De Silva
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK; Oxford University Hospitals NHS Foundation Trust, NIHR Oxford Biomedical Research Centre, Oxford, UK
| | | | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK; Oxford University Hospitals NHS Foundation Trust, NIHR Oxford Biomedical Research Centre, Oxford, UK.
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Orlans HO, Barnard AR, MacLaren RE. Dynamic in vivo quantification of rod photoreceptor degeneration using fluorescent reporter mouse models of retinitis pigmentosa. Exp Eye Res 2020; 190:107895. [DOI: 10.1016/j.exer.2019.107895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/25/2019] [Accepted: 12/04/2019] [Indexed: 02/01/2023]
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11
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Orlans HO, Merrill J, Barnard AR, Charbel Issa P, Peirson SN, MacLaren RE. Filtration of Short-Wavelength Light Provides Therapeutic Benefit in Retinitis Pigmentosa Caused by a Common Rhodopsin Mutation. Invest Ophthalmol Vis Sci 2019; 60:2733-2742. [PMID: 31247114 DOI: 10.1167/iovs.19-26964] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The role of light exposure in accelerating retinitis pigmentosa (RP) remains controversial. Faster degeneration has however been observed in the inferior than superior retina in several forms ("sector" RP), including those caused by the rhodopsin P23H mutation, suggesting a modifying role of incident light exposure in such cases. Rearing of equivalent animal models in complete darkness has been shown to slow the degeneration. Here we investigate the use of red filters as a potential treatment strategy, with the hypothesis that minimizing retinal exposure to light <600 nm to which rods are maximally sensitive may provide therapeutic benefit. Methods Knockin mice heterozygous for the P23H dominant rhodopsin mutation (RhoP23H/+) housed in red-tinted plastic cages were divided at weaning into either untinted or red-tinted cages. Subsequently, photoreceptor layer (PRL) thickness was measured by spectral-domain ocular coherence tomography, retinal function quantified by ERG, and cone morphology determined by immunohistochemical analysis (IHC) of retinal flatmounts. Results Mice remaining in red-tinted cages had a significantly greater PRL thickness than those housed in untinted cages at all time points. Red housing also led to a highly significant rescue of retinal function as determined by both dark- and light-adapted ERG responses. IHC further revealed a dramatic benefit on cone morphology and number in the red- as compared with the clear-housed group. Conclusions Limitation of short-wavelength light exposure significantly slows degeneration in the RhoP23H/+ mouse model. Red filters may represent a cost-effective and low-risk treatment for patients with rod-cone dystrophy in whom a sectoral phenotype is noted.
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Affiliation(s)
- Harry O Orlans
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, United Kingdom.,Western Eye Hospital, London, United Kingdom
| | - Jonathon Merrill
- Biomedical Services, University of Oxford, Oxford, United Kingdom
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, United Kingdom
| | - Peter Charbel Issa
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford, United Kingdom
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, United Kingdom
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford, United Kingdom
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12
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Hassall MM, Barnard AR, Orlans HO, McClements ME, Charbel Issa P, Aslam SA, MacLaren RE. A Novel Achromatopsia Mouse Model Resulting From a Naturally Occurring Missense Change in Cngb3. Invest Ophthalmol Vis Sci 2019; 59:6102-6110. [PMID: 30592498 DOI: 10.1167/iovs.18-24328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose A local colony of inbred mice (129S6/SvEvTac origin), in isolation for over a decade, were found to have absent light-adapted electroretinogram (ERG) responses. We investigated the inheritance and genetic basis of this phenotype of cone photoreceptor function loss. Methods An affected 129S6/SvEvTac colony animal was outcrossed to a C57BL/6J mouse and intercrossed to investigate inheritance in the F2 generation. We performed ERG testing and targeted resequencing on genes of interest (Gnat2, Cnga3, Cngb3, Pde6c, Hcn1, Syne2). The eyes of a subset of animals underwent histologic immunostaining. Results All 129S6/SvEvTac colony animals tested lacked cone pathway function by ERG testing (n = 12), although rod pathway-based ERG responses remained unaffected. Outcross-intercross breeding showed a recessive inheritance pattern. A novel missense mutation was identified in the Cngb3 gene, which causes an amino acid substitution at a conserved residue (NM_013927)c.692G>A; p.(R231H). The recessive phenotype only affected homozygotes (χ2 = 39, P = 3.2e-10). Cones had normal morphology at postnatal day (PND) 70, but cone cell counts declined from PND 30 to PND 335 (P = 0.038), indicating progressive cone photoreceptor death. Conclusions We identified the spontaneous occurrence of a 10th model of cone photoreceptor function loss (cpfl10) in an isolated line of inbred mice. Our results indicate that this is caused by a novel missense mutation in the Cngb3 gene, with a fully recessive inheritance pattern. This mouse may provide a more appropriate background against which to assess CNGB3 achromatopsia gene therapy for missense mutations.
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Affiliation(s)
- Mark M Hassall
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Harry O Orlans
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Peter Charbel Issa
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Sher A Aslam
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
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13
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McClements ME, Barnard AR, Singh MS, Charbel Issa P, Jiang Z, Radu RA, MacLaren RE. An AAV Dual Vector Strategy Ameliorates the Stargardt Phenotype in Adult Abca4-/- Mice. Hum Gene Ther 2018; 30:590-600. [PMID: 30381971 DOI: 10.1089/hum.2018.156] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The recent approval in the United States of the first adeno-associated viral (AAV) vector for the treatment of an inherited retinal degeneration validates this approach for the treatment of many other diseases. A major limiting factor continues to be the size restriction of the AAV transgene at under 5 kb. Stargardt disease is the most prevalent form of recessively inherited blindness and is caused by mutations in ABCA4, the gene that codes for ATP-binding cassette transporter protein family member 4, which has a coding sequence length of 6.8 kb. Dual vector approaches increase the capacity of AAV gene therapy, but at the cost of substantially reduced levels of target protein, which may be insufficient to achieve a therapeutic effect. Here we show that the efficacy of recombination of dual vectors is dependent on the length of DNA overlap between two transgenes. With optimized recombination, full-length ABCA4 protein is expressed in the photoreceptor outer segments of Abca4-/- mice at levels sufficient to reduce bisretinoid formation and correct the autofluorescent phenotype. These observations support a dual vector approach in future clinical trials using AAV gene therapy to treat Stargardt disease.
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Affiliation(s)
- Michelle E McClements
- 1 Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Alun R Barnard
- 1 Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | | | - Peter Charbel Issa
- 1 Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,3 Oxford Eye Hospital, Oxford, United Kingdom
| | - Zhichun Jiang
- 4 Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
| | - Roxana A Radu
- 4 Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
| | - Robert E MacLaren
- 1 Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,3 Oxford Eye Hospital, Oxford, United Kingdom
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14
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Zhao J, Ueda K, Riera M, Kim HJ, Sparrow JR. Bisretinoids mediate light sensitivity resulting in photoreceptor cell degeneration in mice lacking the receptor tyrosine kinase Mer. J Biol Chem 2018; 293:19400-19410. [PMID: 30352873 DOI: 10.1074/jbc.ra118.005949] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/19/2018] [Indexed: 12/13/2022] Open
Abstract
The receptor tyrosine kinase Mer is expressed by retinal pigment epithelial (RPE) cells and participates in photoreceptor outer-segment phagocytosis, a process enabling membrane renewal. Mutations in the gene encoding MERTK cause blinding retinitis pigmentosa in humans. Targeted Mertk disruption in mice causes defective RPE-mediated phagocytosis of the outer segments, leading to deposition of autofluorescent debris at the RPE-photoreceptor cell interface, followed by photoreceptor cell degeneration. Here, we show that retinaldehyde adducts (bisretinoid fluorophores) that form in photoreceptor outer segments occupy the unphagocytosed outer-segment debris that accumulates in Mertk -/- mice. Bisretinoids measured by HPLC were elevated in Mertk -/- mice compared with WT animals. Bisretinoids were also more abundant in albino Mertk -/- mice expressing leucine at position 450 of the isomerase RPE65 (Rpe65-Leu450) rather than the variant methionine (Rpe65-450Met) that yields lower bisretinoid levels. In Royal College of Surgeons rats having dysfunctional Mertk, bisretinoids were higher than in WT rats. Intensities of in vivo fundus autofluorescence were higher in Mertk -/- mice than in WT mice and peaked earlier in albino Mertk -/-/Rpe65-Leu450 mice than in albino Mertk -/-/Rpe65-450Met mice. Of note, the rate of photoreceptor cell degeneration was more rapid in albino Mertk -/- mice exposed to higher levels of intraocular light (albino versus pigmented mice) and in mice carrying Rpe65-Leu450 than in Rpe65-450Met mice, revealing a link between bisretinoid accumulation and light-mediated acceleration of photoreceptor cell degeneration. In conclusion, the light sensitivity of photoreceptor cell degeneration arising from Mertk deficiency is consistent with the known phototoxicity of bisretinoids.
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Affiliation(s)
- Jin Zhao
- From the Departments of Ophthalmology and
| | - Keiko Ueda
- From the Departments of Ophthalmology and
| | | | | | - Janet R Sparrow
- From the Departments of Ophthalmology and .,Pathology and Cell Biology, Columbia University Medical Center, New York, New York 10032
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15
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Development of an inducible anti-VEGF rAAV gene therapy strategy for the treatment of wet AMD. Sci Rep 2018; 8:11763. [PMID: 30082848 PMCID: PMC6079038 DOI: 10.1038/s41598-018-29726-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/16/2018] [Indexed: 12/15/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) is a key mediator in the development and progression of choroidal neovascularization (CNV) in patients with wet age-related macular degeneration (AMD). As a consequence, current treatment strategies typically focus on the administration of anti-VEGF agents, such as Aflibercept (Eylea), that inhibit VEGF function. While this approach is largely successful at counteracting CNV progression, the treatment can require repetitive (i.e. monthly) intravitreal injections of the anti-VEGF agent throughout the patient’s lifetime, imposing a substantial financial and medical burden on the patient. Moreover, repetitive injection of anti-VEGF agents over a period of years may encourage progression of retinal and choroidal atrophy in patients with AMD, leading to a decrease in visual acuity. Herein, we have developed a single-injection recombinant adeno-associated virus (rAAV)-based gene therapy treatment for wet AMD that prevents CNV formation through inducible over-expression of Eylea. First, we demonstrate that by incorporating riboswitch elements into the rAAV expression cassette allows protein expression levels to be modulated in vivo through oral supplementation on an activating ligand (e.g. tetracycline). We subsequently utilized this technology to modulate the intraocular concentration of Eylea following rAAV delivery, leading to nearly complete (p = 0.0008) inhibition of clinically significant CNV lesions in an established mouse model of wet AMD. The results shown in this study pave the way for the development of a personalized gene therapy strategy for the treatment of wet AMD that is substantially less invasive and more clinically adaptable than the current treatment paradigm of repetitive bolus injections of anti-VEGF agents.
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16
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Peripapillary fluorescence lifetime reveals age-dependent changes using fluorescence lifetime imaging ophthalmoscopy in rats. Exp Eye Res 2018; 176:110-120. [PMID: 29990482 DOI: 10.1016/j.exer.2018.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/28/2018] [Accepted: 07/06/2018] [Indexed: 11/24/2022]
Abstract
Many fundus diseases accompany fundus autofluorescence change. Fluorescence lifetime imaging ophthalmoscope (FLIO) is a latest technique in imaging fundus autofluorescence. With FLIO, the fundus fluorescence lifetime (FLT) is recorded topographically, assisting to diagnose and monitor multiple fundus diseases. The purpose of this study was to evaluate the repeatability of FLT using FLIO on adult rats and to analyze the age-dependency of the peripapillary FLT of the fundus in a short spectral channel (498-560 nm) and a long spectral channel (560-720 nm). Sprague Dawley rats (n of eyes = 10) were used for repeatability experiments. Age-dependent changes were investigated in young (two months old, n of eyes = 20) and old (eight months old, n of eyes = 10) rats. Repeatability experiments showed highly corresponding data for all segments in both spectral channel, with higher repeatability in the short spectral channel. FLT decreased significantly in all areas in the short (young: 991 ± 29 ps; old: 547 ± 42 ps) and long (young: 382 ± 28 ps; old: 261 ± 16 ps) spectral channels, indicating an overall metabolic change of the fundus in old animals. FLT of veins increased in the short spectral channel (young: 385 ± 43 ps; old: 424 ± 25 ps) and no change was observed in the long spectral channel (young: 274 ± 9 ps; old: 269 ± 24 ps). FLIO represents a highly repeatable and sensitive method to detect changes of the FLT in aged eyes for monitoring the degeneration of the rodent retinae.
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17
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Orlans HO, Edwards TL, De Silva SR, Patrício MI, MacLaren RE. Human Retinal Explant Culture for Ex Vivo Validation of AAV Gene Therapy. Methods Mol Biol 2018; 1715:289-303. [PMID: 29188522 DOI: 10.1007/978-1-4939-7522-8_21] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recombinant adeno-associated viral (AAV) vectors have been successfully employed as the mode of gene delivery in several clinical trials for the treatment of inherited retinal diseases to date. The design of such vectors is critical in determining cellular tropism and level of subsequent gene expression that may be achieved following viral delivery. Here we describe a system for living retinal tissue extraction, ex vivo culture, viral transduction and assessment of transgene expression that may be used to assess viral constructs for gene therapy in the human retina at a preclinical stage.
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Affiliation(s)
- Harry O Orlans
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK.
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
- Moorfields Eye Hospital, London, UK.
| | - Thomas L Edwards
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Samantha R De Silva
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Maria I Patrício
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Moorfields Eye Hospital, London, UK
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18
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Reid CA, Ertel KJ, Lipinski DM. Improvement of Photoreceptor Targeting via Intravitreal Delivery in Mouse and Human Retina Using Combinatory rAAV2 Capsid Mutant Vectors. Invest Ophthalmol Vis Sci 2017; 58:6429-6439. [PMID: 29260200 PMCID: PMC5736327 DOI: 10.1167/iovs.17-22281] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose Effective intravitreal gene delivery to cells of the central retina (i.e., photoreceptors) would be of substantial benefit for treating patients with retinal diseases, such as achromatopsia, where retinal detachment from a subretinal may be harmful. Previous studies demonstrated that mutation of the recombinant adeno-associated virus (rAAV) capsid through introduction of peptide insertions or amino acid substitutions dramatically alters vector tropism. Herein, we evaluate the photoreceptor transduction efficiency of three rAAV2/2-based capsid mutant vectors: rAAV2/2[7m8], rAAV2/2[QuadYF+TV], and a chimeric vector incorporating both mutations (termed rAAV2/2[MAX]) following intravitreal delivery in mice. Furthermore, we evaluate the transduction efficiency of rAAV2/2[MAX] using explanted human central retinal samples to address clinical translatability. Methods Vectors containing a GFP or mCherry reporter gene were intravitreally injected into C57BL/6J or Nrl-EGFP mice, respectively. Transduction was assessed in vivo utilizing a custom multiline confocal scanning laser ophthalmoscope. Injected Nrl-EGFP mouse retinas were used to quantify transduced photoreceptors using flow cytometry. Postmortem human retinal tissue was cultured following administration of rAAV2/2[MAX]. C57BL/6J retinas and human explants were cryosectioned to determine vector tropism. Results The chimeric vector rAAV2/2[MAX] transduced significantly higher proportions of the retina than did either single mutant serotypes following intravitreal delivery in murine retina, including inner retinal cells and photoreceptors. Vector rAAV2[MAX] demonstrated transduction of human photoreceptors and ganglion cells. Conclusions Transduction observed via rAAV2/2[MAX] indicates that combining mutations with complementary mechanisms of action in a single vector results in enhanced transduction. rAAV2/2[MAX] also presented the ability to transduce human photoreceptors and ganglion cells, indicating potential for efficient intravitreal vector delivery.
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Affiliation(s)
- Christopher A Reid
- Department of Ophthalmology, Eye Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Kristina J Ertel
- Department of Ophthalmology, Eye Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Daniel M Lipinski
- Department of Ophthalmology, Eye Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States.,Nuffield Laboratory of Ophthalmology, Department of Clinical Neuroscience, University of Oxford, Oxford, United Kingdom
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19
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Hickey DG, Edwards TL, Barnard AR, Singh MS, de Silva SR, McClements ME, Flannery JG, Hankins MW, MacLaren RE. Tropism of engineered and evolved recombinant AAV serotypes in the rd1 mouse and ex vivo primate retina. Gene Ther 2017; 24:787-800. [PMID: 28872643 PMCID: PMC5746594 DOI: 10.1038/gt.2017.85] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 07/19/2017] [Accepted: 08/23/2017] [Indexed: 11/09/2022]
Abstract
There is much debate on the adeno-associated virus (AAV) serotype that best targets specific retinal cell types and the route of surgical delivery-intravitreal or subretinal. This study compared three of the most efficacious AAV vectors known to date in a mouse model of retinal degeneration (rd1 mouse) and macaque and human retinal explants. Green fluorescent protein (GFP) driven by a ubiquitous promoter was packaged into three AAV capsids: AAV2/8(Y733F), AAV2/2(quad Y-F) and AAV2/2(7m8). Overall, AAV2/2(7m8) transduced the largest area of retina and resulted in the highest level of GFP expression, followed by AAV2/2(quad Y-F) and AAV2/8(Y733F). AAV2/2(7m8) and AAV2/2(quad Y-F) both resulted in similar patterns of transduction whether they were injected intravitreally or subretinally. AAV2/8(Y733F) transduced a significantly smaller area of retina when injected intravitreally compared with subretinally. Retinal ganglion cells, horizontal cells and retinal pigment epithelium expressed relatively high levels of GFP in the mouse retina, whereas amacrine cells expressed low levels of GFP and bipolar cells were infrequently transduced. Cone cells were the most frequently transduced cell type in macaque retina explants, whereas Müller cells were the predominant transduced cell type in human retinal explants. Of the AAV serotypes tested, AAV2/2(7m8) was the most effective at transducing a range of cell types in degenerate mouse retina and macaque and human retinal explants.
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Affiliation(s)
- D G Hickey
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - T L Edwards
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - A R Barnard
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - M S Singh
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.,Moorfields Eye Hospital NHS Foundation Trust NIHR Biomedical Research Centre, London, UK
| | - S R de Silva
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - M E McClements
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - J G Flannery
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - M W Hankins
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.,Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK
| | - R E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.,Moorfields Eye Hospital NHS Foundation Trust NIHR Biomedical Research Centre, London, UK.,Oxford University Hospitals NHS Trust Biomedical Research Centre, Oxford, UK
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20
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THE EFFECT OF PHOTOPIGMENT BLEACHING ON FUNDUS AUTOFLUORESCENCE IN ACUTE CENTRAL SEROUS CHORIORETINOPATHY. Retina 2017; 37:568-577. [PMID: 27429375 DOI: 10.1097/iae.0000000000001170] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the effect of photobleaching on fundus autofluorescence (FAF) images in acute central serous chorioretinopathy. METHODS We obtained prephotobleaching and postphotobleaching images using an Optomap 200Tx, and photobleaching was induced with a Heidelberg Retina Angiograph 2. Degrees of photobleaching were assessed as grayscale values in Optomap images. Concordances among the three kinds of images were analyzed. Hyper-AF lesions in prephotobleaching images were classified as Type 1 (changed to normal-AF after photobleaching) and Type 2 (unchanged after photobleaching). The FAF composite patterns of central serous chorioretinopathy lesions were classified as diffuse or mottled. Initial and final best-corrected visual acuity, central retinal thickness, and disease duration were compared according to fovea FAF type. RESULTS Forty-one eyes of 41 patients were analyzed. The lesion brightness of postphotobleaching Optomap FAF showed greater concordance with Heidelberg Retina Angiograph 2 FAF (94.74%) than the prephotobleaching Optomap FAF (80.49%). Eyes with Type 1 fovea had greater initial and final best-corrected visual acuity (20/23 vs. 20/41, 20/21 vs. 20/32, P < 0.0001, P = 0.001, respectively) and shorter disease duration (19.68 ± 12.98 vs. 51.55 ± 44.98 days, P = 0.043) than those with Type 2 fovea. However, eyes with diffuse Type 2 fovea had only lower initial and final best-corrected visual acuity (20/23 vs. 20/45, 20/21 vs. 20/36, P < 0.0001, P < 0.0001, respectively) than those with Type 1 fovea. CONCLUSION Understanding the photobleaching effect is necessary for the accurate interpretation of FAF images. Furthermore, comparing prephotobleaching and postphotobleaching FAF images may be helpful for estimation of lesion status in central serous chorioretinopathy.
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21
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Fischer MD, McClements ME, Martinez-Fernandez de la Camara C, Bellingrath JS, Dauletbekov D, Ramsden SC, Hickey DG, Barnard AR, MacLaren RE. Codon-Optimized RPGR Improves Stability and Efficacy of AAV8 Gene Therapy in Two Mouse Models of X-Linked Retinitis Pigmentosa. Mol Ther 2017; 25:1854-1865. [PMID: 28549772 PMCID: PMC5542800 DOI: 10.1016/j.ymthe.2017.05.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 04/25/2017] [Accepted: 05/05/2017] [Indexed: 12/04/2022] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is generally a severe form of retinitis pigmentosa, a neurodegenerative, blinding disorder of the retina. 70% of XLRP cases are due to mutations in the retina-specific isoform of the gene encoding retinitis pigmentosa GTPase regulator (RPGRORF15). Despite successful RPGRORF15 gene replacement with adeno-associated viral (AAV) vectors being established in a number of animal models of XLRP, progression to human trials has not yet been possible. The inherent sequence instability in the purine-rich region of RPGRORF15 (which contains highly repetitive nucleotide sequences) leads to unpredictable recombination errors during viral vector cloning. While deleted RPGR may show some efficacy in animal models, which have milder disease, the therapeutic effect of a mutated RPGR variant in patients with XLRP cannot be predicted. Here, we describe an optimized gene replacement therapy for human XLRP disease using an AAV8 vector that reliably and consistently produces the full-length correct RPGR protein. The glutamylation pattern in the RPGR protein derived from the codon-optimized sequence is indistinguishable from the wild-type variant, implying that codon optimization does not significantly alter post-translational modification. The codon-optimized sequence has superior stability and expression levels in vitro. Significantly, when delivered by AAV8 vector and driven by the rhodopsin kinase promoter, the codon-optimized RPGR rescues the disease phenotype in two relevant animal models (Rpgr−/y and C57BL/6JRd9/Boc) and shows good safety in C57BL6/J wild-type mice. This work provides the basis for clinical trial development to treat patients with XLRP caused by RPGR mutations.
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Affiliation(s)
- M Dominik Fischer
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, The John Radcliffe Hospital, Levels 5 & 6, West Wing, Headley Way, OX3 9DU Oxford, UK; University Eye Hospital, Center for Opthalmology, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany
| | - Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, The John Radcliffe Hospital, Levels 5 & 6, West Wing, Headley Way, OX3 9DU Oxford, UK
| | - Cristina Martinez-Fernandez de la Camara
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, The John Radcliffe Hospital, Levels 5 & 6, West Wing, Headley Way, OX3 9DU Oxford, UK
| | - Julia-Sophia Bellingrath
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, The John Radcliffe Hospital, Levels 5 & 6, West Wing, Headley Way, OX3 9DU Oxford, UK; University Eye Hospital, Center for Opthalmology, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany
| | - Daniyar Dauletbekov
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, The John Radcliffe Hospital, Levels 5 & 6, West Wing, Headley Way, OX3 9DU Oxford, UK; University Eye Hospital, Center for Opthalmology, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany
| | - Simon C Ramsden
- Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, M13 9WL Manchester, UK
| | - Doron G Hickey
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, The John Radcliffe Hospital, Levels 5 & 6, West Wing, Headley Way, OX3 9DU Oxford, UK
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, The John Radcliffe Hospital, Levels 5 & 6, West Wing, Headley Way, OX3 9DU Oxford, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, The John Radcliffe Hospital, Levels 5 & 6, West Wing, Headley Way, OX3 9DU Oxford, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Trust, The John Radcliffe Hospital, West Wing, Headley Way, OX3 9DU Oxford, UK.
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Jolly JK, Edwards TL, Moules J, Groppe M, Downes SM, MacLaren RE. A Qualitative and Quantitative Assessment of Fundus Autofluorescence Patterns in Patients With Choroideremia. Invest Ophthalmol Vis Sci 2017; 57:4498-4503. [PMID: 27750291 PMCID: PMC5860725 DOI: 10.1167/iovs.15-18362] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Purpose We set out to characterize the pattern of fundus autofluorescence (AF) loss in choroideremia (CHM) patients of varying ages and disease severity in order to determine the average rate of progression of this potential disease biomarker. Methods Fifty consecutive CHM patients (100 eyes) attending outpatient clinics at Oxford Eye Hospital underwent analysis with the Heidelberg OCT Spectralis with autofluorescence capabilities. The area of residual AF was traced using Heidelberg Eye Explorer. Bland-Altman analysis was used to calculate the coefficient of repeatability (CR). The degree of AF loss was correlated to different ages and the pattern of residual AF constructed into color-coded maps in order to gain insight into the mechanism of disease progression. Results The CR for measurement of AF area is <1%, indicating that a small change is likely to be significant. Correlation of patient age and area of residual AF produced a clinically relevant index of expected anatomic disease. Progression is 7.7% of the residual area each year (95% confidence intervals 7.0%–8.2%) and follows a logarithmic pattern with age (r = 0.95, P < 0.001). From this we derived the mean half-life of AF as 9 years. Qualitatively, the pattern of remaining AF centered on a point temporal to the fovea. Conclusions The area of residual AF in CHM can be measured reproducibly and shows a distinct pattern of loss. The measured residual area is inversely correlated to age. The ratio of the two variables may provide useful information regarding the rate of progression for any one individual at a given point in time.
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Affiliation(s)
- Jasleen K Jolly
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford Biomedical Research Centre, Oxford, United Kingdom 2Oxford Eye Hospital, John Radcliffe Hospital, Oxford, United Kingdom 3Moorfields Eye Hospital-UCL Institute of Ophthalmology, National Institute for Health Research Biomedical Research Centre, London, United Kingdom
| | - Thomas L Edwards
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford Biomedical Research Centre, Oxford, United Kingdom 2Oxford Eye Hospital, John Radcliffe Hospital, Oxford, United Kingdom
| | | | - Markus Groppe
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Susan M Downes
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford Biomedical Research Centre, Oxford, United Kingdom 2Oxford Eye Hospital, John Radcliffe Hospital, Oxford, United Kingdom
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford Biomedical Research Centre, Oxford, United Kingdom 2Oxford Eye Hospital, John Radcliffe Hospital, Oxford, United Kingdom 3Moorfields Eye Hospital-UCL Institute of Ophthalmology, National Institute for Health Research Biomedical Research Centre, London, United Kingdom
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Yan W, Yao L, Liu W, Sun K, Zhang Z, Zhang L. A kind of rd1 mouse in C57BL/6J mice from crossing with a mutated Kunming mouse. Gene 2017; 607:9-15. [PMID: 28077313 DOI: 10.1016/j.gene.2017.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 01/01/2017] [Accepted: 01/06/2017] [Indexed: 11/18/2022]
Abstract
We occasionally discovered a mouse with spontaneous retinitis pigmentosa (RP) from Kunming (KM) mouse breeding colony, with no obvious waveforms in ERG recordings. The aim of this study is to cross the spontaneously hereditary retinal degeneration mice (temporarily designated as KM/rd mice) derived from KM mice with C57BL/6J mice to establish a congenic inbred strain (temporarily designated as the B6/rd mice), and study the ocular phenotype and genotype of the mice. Fundus photography, tissue morphology, electroretinography (ERG), qRT-PCR, western blot and DNA sequence analysis were performed to observe the ocular phenotype and genotype of KM/rd and B6/rd mice. The fundus photography showed progressive retinal vascular degeneration and depigmentation in KM/rd and B6/rd mice. Compared to wild-type mice, the histological analysis revealed that the outer nuclear layer of the mutated mice was significantly reduced at 14days post born (P14), and almost disappeared by P21. No obvious waveforms were detected at P14 and P21 in the ERG from KM/rd and B6/rd mice. qRT-PCR results showed that the expression quantities of mRNA of pde6b gene in KM/rd and B6/rd mice were significantly lower compared with those of wild-type controls at P21. Western blot results confirmed an abnormal protein expression of pde6b gene in KM/rd and B6/rd mice with no protein products, while there was an obvious protein expression in wild-type mice. The nonsense mutation in exon 7 (a mutation that changes the codon 347 from TAC to TAA) in the pde6b gene of KM/rd and B6/rd mice was identified by genomic DNA sequence analysis. All these findings revealed that the ocular phenotype and genotype of KM/rd and B6/rd mice were similar to those of rd1 mice, which indicates that KM/rd and B6/rd mice can be used as an RP mouse model.
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Affiliation(s)
- Weiming Yan
- Department of Clinical Medicine, Faculty of Aerospace Medicine, Key Laboratory of Aerospace Medicine of the National Education Ministry, The Fourth Military University, Xi'an, Shaanxi Province, China
| | - Lu Yao
- Department of Clinical Medicine, Faculty of Aerospace Medicine, Key Laboratory of Aerospace Medicine of the National Education Ministry, The Fourth Military University, Xi'an, Shaanxi Province, China
| | - Wei Liu
- Medical Experiment Center, Shaanxi University of Chinese Medicine, Shiji Ave., Xi'an-Xianyang New Ecomic Zone, Xi'an, Shaanxi Province, China
| | - Kai Sun
- Department of Clinical Medicine, Faculty of Aerospace Medicine, Key Laboratory of Aerospace Medicine of the National Education Ministry, The Fourth Military University, Xi'an, Shaanxi Province, China
| | - ZuoMing Zhang
- Department of Clinical Medicine, Faculty of Aerospace Medicine, Key Laboratory of Aerospace Medicine of the National Education Ministry, The Fourth Military University, Xi'an, Shaanxi Province, China.
| | - Lei Zhang
- Department of Clinical Medicine, Faculty of Aerospace Medicine, Key Laboratory of Aerospace Medicine of the National Education Ministry, The Fourth Military University, Xi'an, Shaanxi Province, China.
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Patrício MI, Barnard AR, Orlans HO, McClements ME, MacLaren RE. Inclusion of the Woodchuck Hepatitis Virus Posttranscriptional Regulatory Element Enhances AAV2-Driven Transduction of Mouse and Human Retina. MOLECULAR THERAPY. NUCLEIC ACIDS 2016; 6:198-208. [PMID: 28325286 PMCID: PMC5363497 DOI: 10.1016/j.omtn.2016.12.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/13/2016] [Accepted: 12/13/2016] [Indexed: 11/26/2022]
Abstract
The woodchuck hepatitis virus posttranscriptional regulatory element (WPRE) has been included in the transgene cassette of adeno-associated virus (AAV) in several gene therapy clinical trials, including those for inherited retinal diseases. However, the extent to which WPRE increases transgene expression in the retina is still unclear. To address this question, AAV2 vectors containing a reporter gene with and without WPRE were initially compared in vitro and subsequently in vivo by subretinal delivery in mice. In both instances, the presence of WPRE led to significantly higher levels of transgene expression as measured by fundus fluorescence, western blot, and immunohistochemistry. The two vectors were further compared in human retinal explants derived from patients undergoing clinically indicated retinectomy, where again the presence of WPRE resulted in an enhancement of reporter gene expression. Finally, an analogous approach using a transgene currently employed in a clinical trial for choroideremia delivered similar results both in vitro and in vivo, confirming that the WPRE effect is transgene independent. Our data fully support the inclusion of WPRE in ongoing and future AAV retinal gene therapy trials, where it may allow a therapeutic effect to be achieved at an overall lower dose of vector.
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Affiliation(s)
- Maria I Patrício
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Harry O Orlans
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; Moorfields Eye Hospital, NHS Foundation Trust, London EC1V 2PD, UK
| | - Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; Moorfields Eye Hospital, NHS Foundation Trust, London EC1V 2PD, UK.
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25
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De Silva SR, Charbel Issa P, Singh MS, Lipinski DM, Barnea-Cramer AO, Walker NJ, Barnard AR, Hankins MW, MacLaren RE. Single residue AAV capsid mutation improves transduction of photoreceptors in the Abca4 -/- mouse and bipolar cells in the rd1 mouse and human retina ex vivo. Gene Ther 2016; 23:767-774. [PMID: 27416076 PMCID: PMC5097463 DOI: 10.1038/gt.2016.54] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 04/12/2016] [Accepted: 04/20/2016] [Indexed: 02/08/2023]
Abstract
Gene therapy using adeno-associated viral (AAV) vectors for the treatment of retinal degenerations has shown safety and efficacy in clinical trials. However, very high levels of vector expression may be necessary for the treatment of conditions such as Stargardt disease where a dual vector approach is potentially needed, or in optogenetic strategies for end-stage degeneration in order to achieve maximal light sensitivity. In this study, we assessed two vectors with single capsid mutations, rAAV2/2(Y444F) and rAAV2/8(Y733F) in their ability to transduce retina in the Abca4-/- and rd1 mouse models of retinal degeneration. We noted significantly increased photoreceptor transduction using rAAV2/8(Y733F) in the Abca4-/- mouse, in contrast to previous work where vectors tested in this model have shown low levels of photoreceptor transduction. Bipolar cell transduction was achieved following subretinal delivery of both vectors in the rd1 mouse, and via intravitreal delivery of rAAV2/2(Y444F). The successful use of rAAV2/8(Y733F) to target bipolar cells was further validated on human tissue using an ex vivo culture system of retinal explants. Capsid mutant AAV vectors transduce human retinal cells and may be particularly suited to treat retinal degenerations in which high levels of transgene expression are required.
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Affiliation(s)
- Samantha R De Silva
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Peter Charbel Issa
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Mandeep S Singh
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Daniel M Lipinski
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Alona O Barnea-Cramer
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Nathan J Walker
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
- Moorfields Eye Hospital, NIHR Biomedical Research Centre, UK
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26
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Childs A, Li H, Lewittes DM, Dong B, Liu W, Shu X, Sun C, Zhang HF. Fabricating customized hydrogel contact lens. Sci Rep 2016; 6:34905. [PMID: 27748361 PMCID: PMC5066254 DOI: 10.1038/srep34905] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 09/20/2016] [Indexed: 11/09/2022] Open
Abstract
Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.
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Affiliation(s)
- Andre Childs
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, 78249, USA.,Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
| | - Hao Li
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
| | - Daniella M Lewittes
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
| | - Biqin Dong
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA.,Department of Mechanical Engineering, Northwestern University, Evanston IL 60208, USA
| | - Wenzhong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
| | - Xiao Shu
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
| | - Cheng Sun
- Department of Mechanical Engineering, Northwestern University, Evanston IL 60208, USA
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA.,Department of Ophthalmology, Northwestern University, Chicago IL 60611, USA
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27
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Bell BA, Yuan A, Dicicco RM, Fogerty J, Lessieur EM, Perkins BD. The adult zebrafish retina: In vivo optical sectioning with Confocal Scanning Laser Ophthalmoscopy and Spectral-Domain Optical Coherence Tomography. Exp Eye Res 2016; 153:65-78. [PMID: 27720860 DOI: 10.1016/j.exer.2016.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/02/2016] [Accepted: 10/04/2016] [Indexed: 11/27/2022]
Abstract
Non-invasive imaging is an invaluable diagnostic tool in ophthalmology. Two imaging devices, the scanning laser ophthalmoscope (SLO) and spectral domain optical coherence tomography (SDOCT), emerged from the clinical realm to provide research scientists with a real-time view of ocular morphology in living animals. We utilized these two independent imaging modalities in a complementary manner to perform in vivo optical sectioning of the adult zebrafish retina. Due to the very high optical power of the zebrafish lens, the confocal depth of field is narrow, allowing for detailed en face views of specific retinal layers, including the cone mosaic. Moreover, we demonstrate that both native reflectance, as well as fluorescent features observed by SLO, can be combined with axial in-depth information obtained by SDOCT. These imaging approaches can be used to screen for ocular phenotypes and monitor retinal pathology in a non-invasive manner.
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Affiliation(s)
- Brent A Bell
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States.
| | - Alex Yuan
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States
| | - Rose M Dicicco
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Joseph Fogerty
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Emma M Lessieur
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States; Molecular Medicine PhD Program Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States
| | - Brian D Perkins
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States
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Yao L, Zhang L, Qi LS, Liu W, An J, Wang B, Xue JH, Zhang ZM. The Time Course of Deafness and Retinal Degeneration in a Kunming Mouse Model for Usher Syndrome. PLoS One 2016; 11:e0155619. [PMID: 27186975 PMCID: PMC4871471 DOI: 10.1371/journal.pone.0155619] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 05/02/2016] [Indexed: 01/13/2023] Open
Abstract
Usher syndrome is a group of autosomal recessive diseases characterized by congenital deafness and retinitis pigmentosa. In a mouse model for Usher syndrome, KMush/ush, discovered in our laboratory, we measured the phenotypes, characterized the architecture and morphology of the retina, and quantified the level of expression of pde6b and ush2a between postnatal (P) days 7, and 56. Electroretinograms and auditory brainstem response were used to measure visual and auditory phenotypes. Fundus photography and light microscopy were used to measure the architecture and morphology of the retina. Quantitative real-time PCR was used to measure the expression levels of mRNA. KMush/ush mice had low amplitudes and no obvious waveforms of Electroretinograms after P14 compared with controls. Thresholds of auditory brainstem response in our model were higher than those of controls after P14. By P21, the retinal vessels of KMush/ush mice were attenuated and their optic discs had a waxy pallor. The retinas of KMush/ush mice atrophied and the choroidal vessels were clearly visible. Notably, the architecture of each retinal layer was not different as compared with control mice at P7, while the outer nuclear layer (ONL) and other retinal layers of KMush/ush mice were attenuated significantly between P14 and P21. ONL cells were barely seen in KMush/ush mice at P56. As compared with control mice, the expression of pde6b and ush2a in KMush/ush mice declined significantly after P7. This study is a first step toward characterizing the progression of disease in our mouse model. Future studies using this model may provide insights about the etiology of the disease and the relationships between genotypes and phenotypes providing a valuable resource that could contribute to the foundation of knowledge necessary to develop therapies to prevent the retinal degeneration in patients with Usher Syndrome.
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Affiliation(s)
- Lu Yao
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
| | - Lei Zhang
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
| | - Lin-Song Qi
- Department of Physical Examination, Air Force General Hospital, 30 Fucheng Road, Beijing, China
| | - Wei Liu
- Medical Experiment Center, Shaanxi University of Chinese Medicine, Shiji Ave., Xi'an-Xianyang New Ecomic Zone, 712046, Xi'an, China
| | - Jing An
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
| | - Bin Wang
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
| | - Jun-Hui Xue
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
- * E-mail: (JHX); (ZMZ)
| | - Zuo-Ming Zhang
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
- * E-mail: (JHX); (ZMZ)
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29
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Joshi R, Pankova N, Wang H, Baek DSH, Zhao X, Reyad M, Boyd SR. Spontaneously occurring fundus findings observed using confocal scanning laser ophthalmoscopy in wild type Sprague Dawley rats. Regul Toxicol Pharmacol 2016; 77:160-6. [PMID: 26873774 DOI: 10.1016/j.yrtph.2016.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 11/17/2022]
Abstract
PURPOSE Non-invasive in vivo imaging is an increasingly used component of pre-clinical research. However, to reliably interpret data, it may be necessary to identify and document pre-existent findings prior to initiating long-term or intensive protocols, particularly where toxicity or efficacy is under investigation. Here we report here spontaneously occurring findings from the Sprague Dawley (SD) rat eye using multi-modal confocal scanning laser ophthalmoscopy (cSLO). METHODS As part of ongoing studies, with the goal of excluding animals with abnormalities from further investigation, a total of 165 wild type SD rats (312 eyes) were assessed using cSLO imaging at baseline prior to initiating experiments to detect, describe, and determine the prevalence of spontaneous fundus findings. RESULTS Using fundus autofluorescence (FAF) as the primary screening modality, over 30% of analyzed eyes possessed some fundus finding that differed from the normal composite reference image. Unexpectedly, 100% of eyes demonstrated a diffuse hyperfluorescent region in the posterior pole that was ultimately considered normal, and formed part of the reference. Evaluated by three independent reviewers, five groups of FAF abnormalities were defined, based primarily on shape and size of the lesion. Of these, the most extensive lesions were further analyzed using infrared reflectance (IR) and red free (RF) imaging. White light and autofluorescent microscopy of excised tissue confirmed that the extensive lesions were derived from abnormalities in both the isolated retina and posterior eyecups. CONCLUSIONS Given the newly described hyperfluorescent glow that appears in all eyes, and the high basal rate of spontaneous lesions in the outbred SD rat, we suggest that investigators be aware of the variants of normal, and that baseline in vivo screening be considered prior to initiating intensive or expensive investigation.
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Affiliation(s)
- Rahul Joshi
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada, M5B 1W8
| | - Natalie Pankova
- University of Toronto, Department of Laboratory Medicine and Pathobiology, 1 King's College Circle, Toronto, ON, Canada, M5S 1A8; University of Toronto, Department of Ophthalmology and Vision Sciences, 340 College Street, Toronto, ON, Canada, M5T 3A9; Keenan Research Centre for Biomedical Science, St Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada, M5B 1W8
| | - Hai Wang
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada, M5B 1W8
| | - David Sung Hyeon Baek
- University of Toronto, Department of Laboratory Medicine and Pathobiology, 1 King's College Circle, Toronto, ON, Canada, M5S 1A8; Keenan Research Centre for Biomedical Science, St Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada, M5B 1W8
| | - Xu Zhao
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada, M5B 1W8
| | - Matthew Reyad
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada, M5B 1W8
| | - Shelley R Boyd
- University of Toronto, Department of Laboratory Medicine and Pathobiology, 1 King's College Circle, Toronto, ON, Canada, M5S 1A8; University of Toronto, Department of Ophthalmology and Vision Sciences, 340 College Street, Toronto, ON, Canada, M5T 3A9; Keenan Research Centre for Biomedical Science, St Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada, M5B 1W8; Department of Ophthalmology, St. Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8; Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1.
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30
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Long time remodeling during retinal degeneration evaluated by optical coherence tomography, immunocytochemistry and fundus autofluorescence. Exp Eye Res 2015; 150:122-34. [PMID: 26521765 DOI: 10.1016/j.exer.2015.10.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 01/16/2023]
Abstract
PURPOSE To characterize the relationship between fundus autofluorescence (FAF), Optical Coherence Tomography (OCT) and immunohistochemistry (IHC) over the course of chronic retinal degeneration in the P23H rat. METHODS Homozygous albino P23H rats, Sprague-Dawley (SD) rats as controls and pigmented Long Evans (LE) rats were used. A Spectralis HRA OCT system was used for scanning laser ophthalmoscopy (SLO) imaging OCT and angiography. To determine FAF, fluorescence was excited using diode laser at 488 nm. A fast retina map OCT was performed using the optic nerve as a landmark. IHC was performed to correlate with the findings of OCT and FAF changes. RESULTS During the course of retinal degeneration, the FAF pattern evolved from some spotting at 2 months old to a mosaic of hyperfluorescent dots in rats 6 months and older. Retinal thicknesses progressively diminished over the course of the disease. At later stages of degeneration, OCT documented changes in the retinal layers, however, IHC better identified the cell loss and remodeling changes. Angiography revealed attenuation of the retinal vascular plexus with time. CONCLUSION We provide for the first time a detailed long-term analysis of the course of retinal degeneration in P23H rats using a combination of SLO and OCT imaging, angiography, FAF and IHC. Although, the application of noninvasive methods enables longitudinal studies and will decrease the number of animals needed for a study, IHC is still an essential tool to identify retinal changes at the cellular level.
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Rescue of the Stargardt phenotype in Abca4 knockout mice through inhibition of vitamin A dimerization. Proc Natl Acad Sci U S A 2015; 112:8415-20. [PMID: 26106163 DOI: 10.1073/pnas.1506960112] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Stargardt disease, an ATP-binding cassette, subfamily A, member 4 (ABCA4)-related retinopathy, is a genetic condition characterized by the accelerated accumulation of lipofuscin in the retinal pigment epithelium, degeneration of the neuroretina, and loss of vision. No approved treatment exists. Here, using a murine model of Stargardt disease, we show that the propensity of vitamin A to dimerize is responsible for triggering the formation of the majority of lipofuscin and transcriptional dysregulation of genes associated with inflammation. Data further demonstrate that replacing vitamin A with vitamin A deuterated at the carbon 20 position (C20-D3-vitamin A) impedes the dimerization rate of vitamin A--by approximately fivefold for the vitamin A dimer A2E--and subsequent lipofuscinogenesis and normalizes the aberrant transcription of complement genes without impairing retinal function. Phenotypic rescue by C20-D3-vitamin A was also observed noninvasively by quantitative autofluorescence, an imaging technique used clinically, in as little as 3 months after the initiation of treatment, whereas upon interruption of treatment, the age-related increase in autofluorescence resumed. Data suggest that C20-D3-vitamin A is a clinically amiable tool to inhibit vitamin A dimerization, which can be used to determine whether slowing the dimerization of vitamin A can prevent vision loss caused by Stargardt disease and other retinopathies associated with the accumulation of lipofuscin in the retina.
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Herrmann P, Cowing JA, Cristante E, Liyanage SE, Ribeiro J, Duran Y, Abelleira Hervas L, Carvalho LS, Bainbridge JWB, Luhmann UFO, Ali RR. Cd59a deficiency in mice leads to preferential innate immune activation in the retinal pigment epithelium-choroid with age. Neurobiol Aging 2015; 36:2637-48. [PMID: 26234657 DOI: 10.1016/j.neurobiolaging.2015.05.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 04/30/2015] [Accepted: 05/29/2015] [Indexed: 11/29/2022]
Abstract
Dysregulation of the complement system has been implicated in the pathogenesis of age-related macular degeneration. To investigate consequences of altered complement regulation in the eye with age, we examined Cd59a complement regulator deficient (Cd59a(-/-)) mice between 4 and 15 months. In vivo imaging revealed an increased age-related accumulation of autofluorescent spots in Cd59a(-/-) mice, a feature that reflects accumulation of subretinal macrophages and/or microglia. Despite this activation of myeloid cells in the eye, Cd59a(-/-) mice showed normal retinal histology and function as well as normal choroidal microvasculature. With age, they revealed increased expression of activators of the alternative complement pathway (C3, Cfb, Cfd), in particular in the retinal pigment epithelium (RPE)-choroid but less in the retina. This molecular response was not altered by moderately-enhanced light exposure. Cd59a deficiency therefore leads to a preferential age-related dysregulation of the complement system in the RPE-choroid, that alone or in combination with light as a trigger, is not sufficient to cause choroidal vascular changes or retinal degeneration and dysfunction. This data emphasizes the particular vulnerability of the RPE-choroidal complex to dysregulation of the alternative complement pathway during aging.
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Affiliation(s)
- Philipp Herrmann
- Department of Genetics, UCL Institute of Ophthalmology, London, UK
| | - Jill A Cowing
- Department of Genetics, UCL Institute of Ophthalmology, London, UK
| | - Enrico Cristante
- Department of Genetics, UCL Institute of Ophthalmology, London, UK
| | | | - Joana Ribeiro
- Department of Genetics, UCL Institute of Ophthalmology, London, UK
| | - Yanai Duran
- Department of Genetics, UCL Institute of Ophthalmology, London, UK
| | | | - Livia S Carvalho
- Department of Genetics, UCL Institute of Ophthalmology, London, UK
| | - James W B Bainbridge
- Department of Genetics, UCL Institute of Ophthalmology, London, UK; NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital, London, UK
| | | | - Robin R Ali
- Department of Genetics, UCL Institute of Ophthalmology, London, UK; NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital, London, UK
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Bosco A, Romero CO, Ambati BK, Vetter ML. In vivo dynamics of retinal microglial activation during neurodegeneration: confocal ophthalmoscopic imaging and cell morphometry in mouse glaucoma. J Vis Exp 2015:e52731. [PMID: 25992962 DOI: 10.3791/52731] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Microglia, which are CNS-resident neuroimmune cells, transform their morphology and size in response to CNS damage, switching to an activated state with distinct functions and gene expression profiles. The roles of microglial activation in health, injury and disease remain incompletely understood due to their dynamic and complex regulation in response to changes in their microenvironment. Thus, it is critical to non-invasively monitor and analyze changes in microglial activation over time in the intact organism. In vivo studies of microglial activation have been delayed by technical limitations to tracking microglial behavior without altering the CNS environment. This has been particularly challenging during chronic neurodegeneration, where long-term changes must be tracked. The retina, a CNS organ amenable to non-invasive live imaging, offers a powerful system to visualize and characterize the dynamics of microglia activation during chronic disorders. This protocol outlines methods for long-term, in vivo imaging of retinal microglia, using confocal ophthalmoscopy (cSLO) and CX3CR1(GFP/+) reporter mice, to visualize microglia with cellular resolution. Also, we describe methods to quantify monthly changes in cell activation and density in large cell subsets (200-300 cells per retina). We confirm the use of somal area as a useful metric for live tracking of microglial activation in the retina by applying automated threshold-based morphometric analysis of in vivo images. We use these live image acquisition and analyses strategies to monitor the dynamic changes in microglial activation and microgliosis during early stages of retinal neurodegeneration in a mouse model of chronic glaucoma. This approach should be useful to investigate the contributions of microglia to neuronal and axonal decline in chronic CNS disorders that affect the retina and optic nerve.
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Affiliation(s)
| | - Cesar O Romero
- Department of Neurobiology & Anatomy, University of Utah
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Lipinski DM, Barnard AR, Singh MS, Martin C, Lee EJ, Davies WIL, MacLaren RE. CNTF Gene Therapy Confers Lifelong Neuroprotection in a Mouse Model of Human Retinitis Pigmentosa. Mol Ther 2015; 23:1308-1319. [PMID: 25896245 DOI: 10.1038/mt.2015.68] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/28/2015] [Indexed: 12/12/2022] Open
Abstract
The long-term outcome of neuroprotection as a therapeutic strategy for preventing cell death in neurodegenerative disorders remains unknown, primarily due to slow disease progression and the inherent difficulty of assessing neuronal survival in vivo. Employing a murine model of retinal disease, we demonstrate that ciliary neurotrophic factor (CNTF) confers life-long protection against photoreceptor degeneration. Repetitive retinal imaging allowed the survival of intrinsically fluorescent cone photoreceptors to be quantified in vivo. Imaging of the visual cortex and assessment of visually-evoked behavioral responses demonstrated that surviving cones retain function and signal correctly to the brain. The mechanisms underlying CNTF-mediated neuroprotection were explored through transcriptome analysis, revealing widespread upregulation of proteolysis inhibitors, which may prevent cellular/extracellular matrix degradation and complement activation in neurodegenerative diseases. These findings provide insights into potential novel therapeutic avenues for diseases such as retinitis pigmentosa and amyotrophic lateral sclerosis, for which CNTF has been evaluated unsuccessfully in clinical trials.
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Affiliation(s)
- Daniel M Lipinski
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Biomedical Research Centre, University of Oxford, Oxford, UK; Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Mandeep S Singh
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Chris Martin
- Department of Psychology, The University of Sheffield, Sheffield, UK
| | - Edward J Lee
- Moorfields Eye Hospital & UCL NIHR Biomedical Research Centre for Ophthalmology, London, UK
| | - Wayne I L Davies
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; School of Animal Biology and University of Western Australia Oceans Institute, University of Western Australia, Perth, Australia
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Biomedical Research Centre, University of Oxford, Oxford, UK; Moorfields Eye Hospital & UCL NIHR Biomedical Research Centre for Ophthalmology, London, UK.
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Aredo B, Zhang K, Chen X, Wang CXZ, Li T, Ufret-Vincenty RL. Differences in the distribution, phenotype and gene expression of subretinal microglia/macrophages in C57BL/6N (Crb1 rd8/rd8) versus C57BL6/J (Crb1 wt/wt) mice. J Neuroinflammation 2015; 12:6. [PMID: 25588310 PMCID: PMC4305240 DOI: 10.1186/s12974-014-0221-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 12/11/2014] [Indexed: 01/02/2023] Open
Abstract
Background Microglia/macrophages (MG/MΦ) are found in the subretinal space in both mice and humans. Our goal was to study the spatial and temporal distribution, the phenotype, and gene expression of subretinal MG/MΦ in mice with normal retinas and compare them to mice with known retinal pathology. Methods We studied C57BL/6 mice with (C57BL/6N), or without (C57BL/6J) the rd8 mutation in the Crb1 gene (which, in the presence of yet unidentified permissive/modifying genes, leads to a retinal degeneration), and documented their fundus appearance and the change with aging. Immunostaining of retinal pigment epithelium (RPE) flat mounts was done for 1) Ionized calcium binding adaptor (Iba)-1, 2) FcγIII/II Receptor (CD16/CD32, abbreviated as CD16), and 3) Macrophage mannose receptor (MMR). Reverse-transcription quantitative PCR (RT-qPCR) was done for genes involved in oxidative stress, complement activation and inflammation. Results The number of yellow fundus spots correlated highly with subretinal Iba-1+ cells. The total number of subretinal MG/MΦ increased with age in the rd8 mutant mice, but not in the wild-type (WT) mice. There was a centripetal shift in the distribution of the subretinal MG/MΦ with age. Old rd8 mutant mice had a greater number of CD16+ MG/MΦ. CD16+ cells had morphological signs of activation, and this was most prominent in old rd8 mutant mice (P <1×10−8 versus old WT mice). Subretinal MG/MΦ in rd8 mutant mice also expressed iNOS and MHC-II, and had ultrastructural signs of activation. Finally, rd8 mutant mouse RPE/ MG/MΦ RNA isolates showed an upregulation of Ccl2, CFB, C3, NF-kβ, CD200R and TNF-alpha. The retinas of rd8 mutant mice showed upregulation of HO-1, C1q, C4, and Nrf-2. Conclusions When compared to C57BL/6J mice, C57BL/6N mice demonstrate increased accumulation of subretinal MG/MΦ, displaying phenotypical, morphological, and gene-expression characteristics consistent with a pro-inflammatory shift. These changes become more prominent with aging and are likely due to the combination of the rd8 mutation and yet unidentified permissive/modulatory genes in the C57BL/6N mice. In contrast, aging leads to a scavenging phenotype in the C57BL/6J subretinal microglia/macrophages. Electronic supplementary material The online version of this article (doi:10.1186/s12974-014-0221-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bogale Aredo
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-9057, USA.
| | - Kaiyan Zhang
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-9057, USA. .,Current address: Department of Ophthalmology, Hainan Provincial People's Hospital, Haikou, Hainan, 570203, PR China.
| | - Xiao Chen
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-9057, USA. .,Current address: Department of Ophthalmology, Wuhan General Hospital of Guangzhou Military Command, Wuhan, 430070, PR China.
| | - Cynthia Xin-Zhao Wang
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-9057, USA.
| | - Tao Li
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-9057, USA.
| | - Rafael L Ufret-Vincenty
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-9057, USA.
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de Silva SR, McClements ME, Hankins MW, MacLaren RE. Adeno-Associated Viral Gene Therapy for Retinal Disorders. NEUROMETHODS 2015. [DOI: 10.1007/978-1-4939-2306-9_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Baek DSH, Liang H, Zhao X, Pankova N, Wang H, Boyd S. Fundus autofluorescence (FAF) non-invasively identifies chorioretinal toxicity in a rat model of retinal pigment epithelium (RPE) damage. J Pharmacol Toxicol Methods 2015; 71:77-82. [DOI: 10.1016/j.vascn.2014.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 08/31/2014] [Accepted: 09/01/2014] [Indexed: 11/17/2022]
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Bell BA, Kaul C, Hollyfield JG. A protective eye shield for prevention of media opacities during small animal ocular imaging. Exp Eye Res 2014; 127:280-7. [PMID: 25245081 DOI: 10.1016/j.exer.2014.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/09/2013] [Accepted: 01/01/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Brent A Bell
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Ave/i31, Cleveland, OH 44195, USA.
| | - Charles Kaul
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Ave/i31, Cleveland, OH 44195, USA
| | - Joe G Hollyfield
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Ave/i31, Cleveland, OH 44195, USA; Department of Ophthalmology, Cleveland Clinic, Lerner College of Medicine, Cleveland, OH, USA
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Imaging retinal ganglion cells: enabling experimental technology for clinical application. Prog Retin Eye Res 2014; 44:1-14. [PMID: 25448921 DOI: 10.1016/j.preteyeres.2014.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 10/04/2014] [Accepted: 10/18/2014] [Indexed: 11/21/2022]
Abstract
Recent advances in clinical ophthalmic imaging have enhanced patient care. However, the ability to differentiate retinal neurons, such as retinal ganglion cells (RGCs), would advance many areas within ophthalmology, including the screening and monitoring of glaucoma and other optic neuropathies. Imaging at the single cell level would take diagnostics to the next level. Experimental methods have provided techniques and insight into imaging RGCs, however no method has yet to be translated to clinical application. This review provides an overview of the importance of non-invasive imaging of RGCs and the clinically relevant capabilities. In addition, we report on experimental data from wild-type mice that received an in vivo intravitreal injection of a neuronal tracer that labelled RGCs, which in turn were monitored for up to 100 days post-injection with confocal scanning laser ophthalmoscopy. We were able to demonstrate efficient and consistent RGC labelling with this delivery method and discuss the issue of cell specificity. This type of experimental work is important in progressing towards clinically applicable methods for monitoring loss of RGCs in glaucoma and other optic neuropathies. We discuss the challenges to translating these findings to clinical application and how this method of tracking RGCs in vivo could provide valuable structural and functional information to clinicians.
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Bell BA, Xie J, Yuan A, Kaul C, Hollyfield JG, Anand-Apte B. Retinal vasculature of adult zebrafish: in vivo imaging using confocal scanning laser ophthalmoscopy. Exp Eye Res 2014; 129:107-18. [PMID: 25447564 DOI: 10.1016/j.exer.2014.10.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 10/15/2014] [Accepted: 10/23/2014] [Indexed: 10/24/2022]
Abstract
Over the past 3 decades the zebrafish (Danio rerio) has become an important biomedical research species. As their use continues to grow additional techniques and tools will be required to keep pace with ongoing research using this species. In this paper we describe a novel method for in vivo imaging of the retinal vasculature in adult animals using a commercially available confocal scanning laser ophthalmoscope (SLO). With this instrumentation, we demonstrate the ability to distinguish diverse vascular phenotypes in different transgenic GFP lines. In addition this technology allows repeated visualization of the vasculature in individual zebrafish over time to document vascular leakage progression and recovery induced by intraocular delivery of proteins that induce vascular permeability. SLO of the retinal vasculature was found to be highly informative, providing images of high contrast and resolution that were capable of resolving individual vascular endothelial cells. Finally, the procedures required to acquire SLO images from zebrafish are non-invasive, simple to perform and can be achieved with low animal mortality, allowing repeated imaging of individual fish.
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Affiliation(s)
- Brent A Bell
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA.
| | - Jing Xie
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Alex Yuan
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Charles Kaul
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Joe G Hollyfield
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Bela Anand-Apte
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
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Flynn E, Ueda K, Auran E, Sullivan JM, Sparrow JR. Fundus autofluorescence and photoreceptor cell rosettes in mouse models. Invest Ophthalmol Vis Sci 2014; 55:5643-52. [PMID: 25015357 DOI: 10.1167/iovs.14-14136] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE This study was conducted to study correlations among fundus autofluorescence (AF), RPE lipofuscin accumulation, and photoreceptor cell degeneration and to investigate the structural basis of fundus AF spots. METHODS Fundus AF images (55° lens; 488-nm excitation) and spectral-domain optical coherence tomography (SD-OCT) scans were acquired in pigmented Rdh8(-/-)/Abca4(-/-) mice (ages 1-9 months) with a confocal scanning laser ophthalmoscope (cSLO). For quantitative fundus AF (qAF), gray levels (GLs) were calibrated to an internal fluorescence reference. Retinal bisretinoids were measured by quantitative HPLC. Histometric analysis of outer nuclear layer (ONL) thicknesses was performed, and cryostat sections of retina were examined by fluorescence microscopy. RESULTS Quantified A2E and qAF intensities increased until age 4 months in the Rdh8(-/-)/Abca4(-/-) mice. The A2E levels declined after 4 months of age, but qAF intensity values continued to rise. The decline in A2E levels in the Rdh8(-/-)/Abca4(-/-) mice paralleled reduced photoreceptor cell viability as reflected in ONL thinning. Hyperautofluorescent puncta in fundus AF images corresponded to photoreceptor cell rosettes in SD-OCT images and histological sections stained with hematoxylin and eosin. The inner segment/outer segment-containing core of the rosette emitted an autofluorescence detected by fluorescence microscopy. CONCLUSIONS When neural retina is disordered, AF from photoreceptor cells can contribute to noninvasive fundus AF images. Hyperautofluorescent puncta in fundus AF images are attributable, in at least some cases, to photoreceptor cell rosettes.
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Affiliation(s)
- Erin Flynn
- Department of Ophthalmology, Columbia University, New York, New York, United States
| | - Keiko Ueda
- Department of Ophthalmology, Columbia University, New York, New York, United States
| | - Emily Auran
- Department of Ophthalmology, Columbia University, New York, New York, United States
| | - Jack M Sullivan
- Research Service, Veterans Administration Western New York Healthcare System, Buffalo, New York, United States
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, New York, United States Department of Pathology and Cell Biology, Columbia University, New York, New York, United States
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Lipinski DM, Barnard AR, Issa PC, Singh MS, De Silva SR, Trabalza A, Eleftheriadou I, Ellison SM, Mazarakis ND, MacLaren RE. Vesicular Stomatitis Virus Glycoprotein– and Venezuelan Equine Encephalitis Virus-Derived Glycoprotein–Pseudotyped Lentivirus Vectors Differentially Transduce Corneal Endothelium, Trabecular Meshwork, and Human Photoreceptors. Hum Gene Ther 2014; 25:50-62. [DOI: 10.1089/hum.2013.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Daniel M. Lipinski
- The Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Alun R. Barnard
- The Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Peter Charbel Issa
- The Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, United Kingdom
- Department of Ophthalmology, University of Bonn, 35127 Bonn, Germany
| | - Mandeep S. Singh
- The Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Samantha R. De Silva
- The Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Antonio Trabalza
- Gene Therapy, Division of Brain Sciences, Faculty of Medicine, Centre of Neuroinflammation & Neurodegeneration, Imperial College London, London W12 0NN, United Kingdom
| | - Ioanna Eleftheriadou
- Gene Therapy, Division of Brain Sciences, Faculty of Medicine, Centre of Neuroinflammation & Neurodegeneration, Imperial College London, London W12 0NN, United Kingdom
| | - Stuart M. Ellison
- Gene Therapy, Division of Brain Sciences, Faculty of Medicine, Centre of Neuroinflammation & Neurodegeneration, Imperial College London, London W12 0NN, United Kingdom
| | - Nicholas D. Mazarakis
- Gene Therapy, Division of Brain Sciences, Faculty of Medicine, Centre of Neuroinflammation & Neurodegeneration, Imperial College London, London W12 0NN, United Kingdom
| | - Robert E. MacLaren
- The Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, United Kingdom
- Moorfields Eye Hospital & NIHR Biomedical Research Centre for Ophthalmology, London EC1V 2PD, United Kingdom
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Charbel Issa P, Barnard AR, Singh MS, Carter E, Jiang Z, Radu RA, Schraermeyer U, MacLaren RE. Fundus autofluorescence in the Abca4(-/-) mouse model of Stargardt disease--correlation with accumulation of A2E, retinal function, and histology. Invest Ophthalmol Vis Sci 2013; 54:5602-12. [PMID: 23761084 DOI: 10.1167/iovs.13-11688] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate fundus autofluorescence (AF) characteristics in the Abca4(-/-) mouse, an animal model for AMD and Stargardt disease, and to correlate findings with functional, structural, and biochemical assessments. METHODS Blue (488 nm) and near-infrared (790 nm) fundus AF images were quantitatively and qualitatively analyzed in pigmented Abca4(-/-) mice and wild type (WT) controls in vivo. Functional, structural, and biochemical assessments included electroretinography (ERG), light and electron microscopic analysis, and A2E quantification. All assessments were performed across age groups. RESULTS In Abca4(-/-) mice, lipofuscin-related 488 nm AF increased early in life with a ceiling effect after 6 months. This increase was first paralleled by an accumulation of typical lipofuscin granules in the retinal pigment epithelium (RPE). Later, lipofuscin and melanin granules decreased in number, whereas melanolipofuscin granules increased. This increase in melanolipofuscin granules paralleled an increase in melanin-related 790 nm AF. Old Abca4(-/-) mice revealed a flecked fundus AF pattern at both excitation wavelengths. The amount of A2E, a major lipofuscin component, increased 10- to 12-fold in 6- to 9-month-old Abca4(-/-) mice compared with controls, while 488 nm AF intensity only increased 2-fold. Despite pronounced lipofuscin accumulation in the RPE of Abca4(-/-) mice, ERG and histology showed a slow age-related thinning of the photoreceptor layer similar to WT controls up to 12 months. CONCLUSIONS Fundus AF can be used to monitor lipofuscin accumulation and melanin-related changes in vivo in mouse models of retinal disease. High RPE lipofuscin may not adversely affect retinal structure or function over prolonged time intervals, and melanin-related changes (melanolipofuscin formation) may occur before the decline in retinal function.
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Affiliation(s)
- Peter Charbel Issa
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, United Kingdom.
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Autofluorescence Images with Carl Zeiss versus Topcon Eye Fundus Camera: A Comparative Study. J Ophthalmol 2013; 2013:309192. [PMID: 23710331 PMCID: PMC3655590 DOI: 10.1155/2013/309192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/01/2013] [Accepted: 04/02/2013] [Indexed: 11/18/2022] Open
Abstract
Purpose. To compare the autofluorescence images of the Zeiss versus Topcon eye fundus cameras and design an objective way to quantify it. Procedures. The IMAGEJ software was used to determine the gray level corresponding to the darkest veins and the peripapillary ring (thresholds), the level of white of the brightest perifoveal area, their difference (contrast level), and the suprathreshold area for each photograph. Results. Carl Zeiss has higher contrast values than Topcon. The Topcon contrast presented a crest with further decline as the suprathreshold area continued to increase. On the contrary, the Zeiss profile did not decline in contrast. Conclusions and Message. The Carl Zeiss camera showed superior contrast ability over the Topcon when performing autofluorescence imaging. We set objective parameters to compare fundus cameras FAF images. These parameters could be the base to objectively measure and determine changes and realize followup to areas of hyper- or hypofluorescence.
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Sparrow JR, Blonska A, Flynn E, Duncker T, Greenberg JP, Secondi R, Ueda K, Delori FC. Quantitative fundus autofluorescence in mice: correlation with HPLC quantitation of RPE lipofuscin and measurement of retina outer nuclear layer thickness. Invest Ophthalmol Vis Sci 2013; 54:2812-20. [PMID: 23548623 DOI: 10.1167/iovs.12-11490] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
PURPOSE Our study was conducted to establish procedures and protocols for quantitative autofluorescence (qAF) measurements in mice, and to report changes in qAF, A2E bisretinoid concentration, and outer nuclear layer (ONL) thickness in mice of different genotypes and age. METHODS Fundus autofluorescence (AF) images (55° lens, 488 nm excitation) were acquired in albino Abca4(-/-), Abca4(+/-), and Abca4(+/+) mice (ages 2-12 months) with a confocal scanning laser ophthalmoscope (cSLO). Gray levels (GLs) in each image were calibrated to an internal fluorescence reference. The bisretinoid A2E was measured by quantitative high performance liquid chromatography (HPLC). Histometric analysis of ONL thicknesses was performed. RESULTS The Bland-Altman coefficient of repeatability (95% confidence interval) was ±18% for between-session qAF measurements. Mean qAF values increased with age (2-12 months) in all groups of mice. qAF was approximately 2-fold higher in Abca4(-/-) mice than in Abca4(+/+) mice and approximately 20% higher in heterozygous mice. HPLC measurements of the lipofuscin fluorophore A2E also revealed age-associated increases, and the fold difference between Abca4(-/-) and wild-type mice was more pronounced (approximately 3-4-fold) than measurable by qAF. Moreover, A2E levels declined after 8 months of age, a change not observed with qAF. The decline in A2E levels in the Abca4(-/-) mice corresponded to reduced photoreceptor cell viability as reflected in ONL thinning beginning at 8 months of age. CONCLUSIONS The qAF method enables measurement of in vivo lipofuscin and the detection of genotype and age-associated differences. The use of this approach has the potential to aid in understanding retinal disease processes and will facilitate preclinical studies.
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Affiliation(s)
- Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, New York 10032, USA.
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Charbel Issa P, De Silva SR, Lipinski DM, Singh MS, Mouravlev A, You Q, Barnard AR, Hankins MW, During MJ, MacLaren RE. Assessment of tropism and effectiveness of new primate-derived hybrid recombinant AAV serotypes in the mouse and primate retina. PLoS One 2013; 8:e60361. [PMID: 23593201 PMCID: PMC3621895 DOI: 10.1371/journal.pone.0060361] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 02/26/2013] [Indexed: 01/08/2023] Open
Abstract
Adeno-associated viral vectors (AAV) have been shown to be safe in the treatment of retinal degenerations in clinical trials. Thus, improving the efficiency of viral gene delivery has become increasingly important to increase the success of clinical trials. In this study, structural domains of different rAAV serotypes isolated from primate brain were combined to create novel hybrid recombinant AAV serotypes, rAAV2/rec2 and rAAV2/rec3. The efficacy of these novel serotypes were assessed in wild type mice and in two models of retinal degeneration (the Abca4(-/-) mouse which is a model for Stargardt disease and in the Pde6b(rd1/rd1) mouse) in vivo, in primate tissue ex-vivo, and in the human-derived SH-SY5Y cell line, using an identical AAV2 expression cassette. We show that these novel hybrid serotypes can transduce retinal tissue in mice and primates efficiently, although no more than AAV2/2 and rAAV2/5 serotypes. Transduction efficiency appeared lower in the Abca4(-/-) mouse compared to wild type with all vectors tested, suggesting an effect of specific retinal diseases on the efficiency of gene delivery. Shuffling of AAV capsid domains may have clinical applications for patients who develop T-cell immune responses following AAV gene therapy, as specific peptide antigen sequences could be substituted using this technique prior to vector re-treatments.
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Affiliation(s)
- Peter Charbel Issa
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Samantha R. De Silva
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Daniel M. Lipinski
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Mandeep S. Singh
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Alexandre Mouravlev
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Qisheng You
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Alun R. Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Mark W. Hankins
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Matthew J. During
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University, Columbus, Ohio, United States of America
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Moorfields Eye Hospital Foundation Trust and UCL Institute of Ophthalmology National Institute for Health Research Biomedical Research Centre, London, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust and National Institute for Health Research Biomedical Research Centre, Oxford, United Kingdom
- * E-mail:
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Deli A, Moetteli L, Ambresin A, Mantel I. Comparison of fundus autofluorescence images acquired by the confocal scanning laser ophthalmoscope (488 nm excitation) and the modified Topcon fundus camera (580 nm excitation). Int Ophthalmol 2013; 33:635-43. [PMID: 23468053 DOI: 10.1007/s10792-013-9749-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 02/22/2013] [Indexed: 11/25/2022]
Abstract
To compare autofluorescence (AF) images obtained with the confocal scanning laser ophthalmoscope (using the Heidelberg retina angiograph; HRA) and the modified Topcon fundus camera, in a routine clinical setting. A prospective comparative study conducted at the Jules-Gonin Eye Hospital. Fifty-six patients from the medical retina clinic. All patients had complete ophthalmic slit-lamp and fundus examinations, colour and red-free fundus photography, AF imaging with both instruments, and fluorescein angiography. Cataract and fixation were graded clinically. AF patterns were analyzed for healthy and pathological features. Differences of image noise were analyzed by cataract grading and fixation. A total of 105 eyes were included. AF patterns discovered by the retina angiograph and the fundus camera images, respectively, were a dark optic disc in 72 % versus 15 %, a dark fovea in 92 % versus 4 %, sub- and intraretinal fluid visible as hyperautofluorescence on HRA images only, lipid exudates visible as hypoautofluorescence on HRA images only. The same autofluorescent pattern was found on both images for geographic atrophy, retinal pigment changes, drusen and haemorrhage. Image noise was significantly associated with the degree of cataract and/or poor fixation, favouring the fundus camera. Images acquired by the fundus camera before and after fluorescein angiography were identical. Fundus AF images differ according to the technical differences of the instruments used. Knowledge of these differences is important not only for correctly interpreting images, but also for selecting the most appropriate instrument for the clinical situation.
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Affiliation(s)
- A Deli
- Ophthalmology Department of the University of Lausanne, Jules-Gonin Eye Hospital, 15 Av. de France-Case postale 133, 1000, Lausanne 7, Switzerland
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Lipinski DM, Thake M, MacLaren RE. Clinical applications of retinal gene therapy. Prog Retin Eye Res 2013; 32:22-47. [DOI: 10.1016/j.preteyeres.2012.09.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 09/04/2012] [Accepted: 09/04/2012] [Indexed: 02/08/2023]
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Long-term in vivo imaging of fibrillar tau in the retina of P301S transgenic mice. PLoS One 2012; 7:e53547. [PMID: 23300938 PMCID: PMC3534024 DOI: 10.1371/journal.pone.0053547] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/28/2012] [Indexed: 01/09/2023] Open
Abstract
Tauopathies are widespread neurodegenerative disorders characterised by the intracellular accumulation of hyperphosphorylated tau. Especially in Alzheimer's disease, pathological alterations in the retina are discussed as potential biomarkers to improve early diagnosis of the disease. Using mice expressing human mutant P301S tau, we demonstrate for the first time a straightforward optical approach for the in vivo detection of fibrillar tau in the retina. Longitudinal examinations of individual animals revealed the fate of single cells containing fibrillar tau and the progression of tau pathology over several months. This technique is most suitable to monitor therapeutic interventions aimed at reducing the accumulation of fibrillar tau. In order to evaluate if this approach can be translated to human diagnosis, we tried to detect fibrillar protein aggregates in the post-mortem retinas of patients that had suffered from Alzheimer's disease or Progressive Supranuclear Palsy. Even though we could detect hyperphosphorylated tau, we did not observe any fibrillar tau or Aß aggregates. In contradiction to previous studies, our observations do not support the notion that Aβ or tau in the retina are of diagnostic value in Alzheimer's disease.
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Geng Y, Dubra A, Yin L, Merigan WH, Sharma R, Libby RT, Williams DR. Adaptive optics retinal imaging in the living mouse eye. BIOMEDICAL OPTICS EXPRESS 2012; 3:715-34. [PMID: 22574260 PMCID: PMC3345801 DOI: 10.1364/boe.3.000715] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 02/13/2012] [Accepted: 02/14/2012] [Indexed: 05/18/2023]
Abstract
Correction of the eye's monochromatic aberrations using adaptive optics (AO) can improve the resolution of in vivo mouse retinal images [Biss et al., Opt. Lett. 32(6), 659 (2007) and Alt et al., Proc. SPIE 7550, 755019 (2010)], but previous attempts have been limited by poor spot quality in the Shack-Hartmann wavefront sensor (SHWS). Recent advances in mouse eye wavefront sensing using an adjustable focus beacon with an annular beam profile have improved the wavefront sensor spot quality [Geng et al., Biomed. Opt. Express 2(4), 717 (2011)], and we have incorporated them into a fluorescence adaptive optics scanning laser ophthalmoscope (AOSLO). The performance of the instrument was tested on the living mouse eye, and images of multiple retinal structures, including the photoreceptor mosaic, nerve fiber bundles, fine capillaries and fluorescently labeled ganglion cells were obtained. The in vivo transverse and axial resolutions of the fluorescence channel of the AOSLO were estimated from the full width half maximum (FWHM) of the line and point spread functions (LSF and PSF), and were found to be better than 0.79 μm ± 0.03 μm (STD)(45% wider than the diffraction limit) and 10.8 μm ± 0.7 μm (STD)(two times the diffraction limit), respectively. The axial positional accuracy was estimated to be 0.36 μm. This resolution and positional accuracy has allowed us to classify many ganglion cell types, such as bistratified ganglion cells, in vivo.
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Affiliation(s)
- Ying Geng
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
- The Institute of Optics, University of Rochester, Rochester, NY 14620, USA
| | - Alfredo Dubra
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
- Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA
- Current address: Eye Institute, Medical College of Wisconsin, WI 53226, USA
| | - Lu Yin
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
| | - William H. Merigan
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
- Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA
| | - Robin Sharma
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
- The Institute of Optics, University of Rochester, Rochester, NY 14620, USA
| | - Richard T. Libby
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
- Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA
| | - David R. Williams
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
- The Institute of Optics, University of Rochester, Rochester, NY 14620, USA
- Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA
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