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Kwon Y, Munsoor J, Kaufmann M, Zheng M, Smirnov AI, Han Z. Polydopamine Nanoparticles as Mimicking RPE Melanin for the Protection of Retinal Cells Against Blue Light-Induced Phototoxicity. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400230. [PMID: 38816934 PMCID: PMC11304300 DOI: 10.1002/advs.202400230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 05/15/2024] [Indexed: 06/01/2024]
Abstract
Exposure of the eyes to blue light can induce the overproduction of reactive oxygen species (ROS) in the retina and retinal pigment epithelium (RPE) cells, potentially leading to pathological damage of age-related macular degeneration (AMD). While the melanin in RPE cells absorbs blue light and prevents ROS accumulation, the loss and dysfunction of RPE melanin due to age-related changes may contribute to photooxidation toxicity. Herein, a novel approach utilizing a polydopamine-replenishing strategy via a single-dose intravitreal (IVT) injection is presented to protect retinal cells against blue light-induced phototoxicity. To investigate the effects of overexposure to blue light on retinal cells, a blue light exposure Nrf2-deficient mouse model is created, which is susceptible to light-induced retinal lesions. After blue light irradiation, retina degeneration and an overproduction of ROS are observed. The polydopamine-replenishing strategy demonstrated effectiveness in maintaining retinal structural integrity and preventing retina degeneration by reducing ROS production in retinal cells and limiting the phototoxicity of blue light exposure. These findings highlight the potential of polydopamine as a simple and effective replenishment for providing photoprotection against high-energy blue light exposure.
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Affiliation(s)
- Yong‐Su Kwon
- Department of OphthalmologyThe University of North Carolina at Chapel HillChapel HillNC27599USA
| | - Julie Munsoor
- Department of OphthalmologyThe University of North Carolina at Chapel HillChapel HillNC27599USA
| | - Mary Kaufmann
- Department of OphthalmologyThe University of North Carolina at Chapel HillChapel HillNC27599USA
| | - Min Zheng
- Department of OphthalmologyThe University of North Carolina at Chapel HillChapel HillNC27599USA
| | - Alex I. Smirnov
- Department of ChemistryNorth Carolina State UniversityRaleighNC27695USA
| | - Zongchao Han
- Department of OphthalmologyThe University of North Carolina at Chapel HillChapel HillNC27599USA
- Division of Pharmacoengineering & Molecular PharmaceuticsEshelman School of PharmacyThe University of North Carolina at Chapel HillChapel HillNC27599USA
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Kunala K, Tang JAH, Parkins K, Hunter JJ. Multispectral label-free in vivo cellular imaging of human retinal pigment epithelium using adaptive optics fluorescence lifetime ophthalmoscopy improves feasibility for low emission analysis and increases sensitivity for detecting changes with age and eccentricity. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:S22707. [PMID: 38962492 PMCID: PMC11221116 DOI: 10.1117/1.jbo.29.s2.s22707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 07/05/2024]
Abstract
Significance Adaptive optics fluorescence lifetime ophthalmoscopy (AOFLIO) provides a label-free approach to observe functional and molecular changes at cellular scale in vivo. Adding multispectral capabilities improves interpretation of lifetime fluctuations due to individual fluorophores in the retinal pigment epithelium (RPE). Aim To quantify the cellular-scale changes in autofluorescence with age and eccentricity due to variations in lipofuscin, melanin, and melanolipofuscin in RPE using multispectral AOFLIO. Approach AOFLIO was performed on six subjects at seven eccentricities. Four imaging channels (λ ex / λ em ) were used: 473/SSC, 473/LSC, 532/LSC, and 765/NIR. Cells were segmented and the timing signals of each pixel in a cell were combined into a single histogram, which were then used to compute the lifetime and phasor parameters. An ANOVA was performed to investigate eccentricity and spectral effects on each parameter. Results A repeatability analysis revealed < 11.8 % change in lifetime parameters in repeat visits for 532/LSC. The 765/NIR and 532/LSC had eccentricity and age effects similar to previous reports. The 473/LSC had a change in eccentricity with mean lifetime and a phasor component. Both the 473/LSC and 473/SSC had changes in eccentricity in the short lifetime component and its relative contribution. The 473/SSC had no trend in eccentricity in phasor. The comparison across the four channels showed differences in lifetime and phasor parameters. Conclusions Multispectral AOFLIO can provide a more comprehensive picture of changes with age and eccentricity. These results indicate that cell segmentation has the potential to allow investigations in low-photon scenarios such as in older or diseased subjects with the co-capture of an NIR channel (such as 765/NIR) with the desired spectral channel. This work represents the first multispectral, cellular-scale fluorescence lifetime comparison in vivo in the human RPE and may be a useful method for tracking diseases.
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Affiliation(s)
- Karteek Kunala
- Stanford University, Byers Eye Institute, Palo Alto, California, United States
| | - Janet A. H. Tang
- University of Rochester, Center for Visual Science, Rochester, New York, United States
- University of Rochester, The Institute of Optics, Rochester, New York, United States
| | - Keith Parkins
- University of Rochester, Center for Visual Science, Rochester, New York, United States
| | - Jennifer J. Hunter
- University of Rochester, Center for Visual Science, Rochester, New York, United States
- University of Rochester, The Institute of Optics, Rochester, New York, United States
- University of Waterloo, School of Optometry and Vision Science, Waterloo, Ontario, Canada
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Anderson G, Borooah S, Megaw R, Bagnaninchi P, Weller R, McLeod A, Dhillon B. UVR and RPE - The Good, the Bad and the degenerate Macula. Prog Retin Eye Res 2024; 100:101233. [PMID: 38135244 DOI: 10.1016/j.preteyeres.2023.101233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 12/15/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023]
Abstract
Ultraviolet Radiation (UVR) has a well-established causative influence within the aetiology of conditions of the skin and the anterior segment of the eye. However, a grounded assessment of the role of UVR within conditions of the retina has been hampered by a historical lack of quantitative, and spectrally resolved, assessment of how UVR impacts upon the retina in terms congruent with contemporary theories of ageing. In this review, we sought to summarise the key findings of research investigating the connection between UVR exposure in retinal cytopathology while identifying necessary avenues for future research which can deliver a deeper understanding of UVR's place within the retinal risk landscape.
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Affiliation(s)
- Graham Anderson
- Centre for Regenerative Medicine, University of Edinburgh, Edinburgh BioQuarter, EH16 4UU, UK
| | - Shyamanga Borooah
- Viterbi Family Department of Ophthalmology, Shiley Eye Institute, UC San Diego, CA, 92093-0946, USA
| | - Roly Megaw
- Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, EH4 2XU, UK; Department of Clinical Ophthalmology, National Health Service Scotland, Edinburgh, EH3 9HA, UK
| | - Pierre Bagnaninchi
- Centre for Regenerative Medicine, University of Edinburgh, Edinburgh BioQuarter, EH16 4UU, UK; Robert O Curle Eyelab, Instute for Regeneration and Repair, Edinburgh BioQuarter, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Richard Weller
- Centre for Inflammation Research, University of Edinburgh, Edinburgh BioQuarter, EH16 4TJ, UK
| | - Andrew McLeod
- School of GeoSciences, University of Edinburgh, Crew Building, King's Buildings, EH9 3FF, UK
| | - Baljean Dhillon
- Department of Clinical Ophthalmology, National Health Service Scotland, Edinburgh, EH3 9HA, UK; Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh BioQuarter, EH16 4SB, UK; Robert O Curle Eyelab, Instute for Regeneration and Repair, Edinburgh BioQuarter, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK.
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Berlin A, Fischer NA, Clark ME, Kar D, Swain TA, Martindale RM, McGwin G, Crosson JN, Sloan KR, Owsley C, Curcio CA. Quantitative Autofluorescence at AMD's Beginnings Highlights Retinal Topography and Grading System Differences: ALSTAR2 Baseline. Ophthalmologica 2024:1-13. [PMID: 38599207 DOI: 10.1159/000538696] [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: 11/28/2023] [Accepted: 03/24/2024] [Indexed: 04/12/2024]
Abstract
INTRODUCTION The aims of the study were to describe baseline quantitative (short-wavelength) autofluorescence (qAF) findings in a large pseudophakic cohort at age-related macular degeneration (AMD)'s beginnings and to assess qAF8 as an outcome measure and evaluate Age-Related Eye Disease Study (AREDS) and Beckman grading systems. METHODS In the ALSTAR2 baseline cohort (NCT04112667), 346 pseudophakic eyes of 188 persons (74.0 ± 5.5 years) were classified as normal (N = 160 by AREDS, 158 by Beckman), early AMD (eAMD) (N = 104, 66), and intermediate AMD (iAMD) (N = 82, 122). Groups were compared via mean qAF intensities in a 6°-8° annulus (qAF8) and maps of differences between observations and the overall mean, divided by standard deviation (Z-score). RESULTS qAF8 did not differ significantly among diagnostic groups by either stratification (p = 0.0869 AREDS; p = 0.0569 by Beckman). Notably, 45 eyes considered eAMD by AREDS became iAMD by Beckman. For AREDS-stratified eyes, Z-score maps showed higher centrally located qAF for normal, near the mean in eAMD, and lower values for iAMD. Maps deviated from this pattern for Beckman-stratified eyes. CONCLUSIONS In a large sample of pseudophakic eyes, qAF8 does not differ overall from normal aging to iAMD but also does not capture the earliest AMD activity in the macula lutea. AREDS classification gives results more consistent with a slow decline in histologic autofluorescence than Beckman classification.
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Affiliation(s)
- Andreas Berlin
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA,
- University Hospital Würzburg, Würzburg, Germany,
| | - Nathan A Fischer
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Retina Consultants of Alabama, Birmingham, Alabama, USA
| | - Mark E Clark
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Deepayan Kar
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Thomas A Swain
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Richard M Martindale
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Retina Consultants of Alabama, Birmingham, Alabama, USA
| | - Gerald McGwin
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jason N Crosson
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Retina Consultants of Alabama, Birmingham, Alabama, USA
| | - Kenneth R Sloan
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Cynthia Owsley
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Fontaine V, Boumedine T, Monteiro E, Fournié M, Gersende G, Sahel JA, Picaud S, Veillet S, Lafont R, Latil M, Dilda PJ, Camelo S. RAR Inhibitors Display Photo-Protective and Anti-Inflammatory Effects in A2E Stimulated RPE Cells In Vitro through Non-Specific Modulation of PPAR or RXR Transactivation. Int J Mol Sci 2024; 25:3037. [PMID: 38474284 PMCID: PMC10932305 DOI: 10.3390/ijms25053037] [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: 12/20/2023] [Revised: 02/23/2024] [Accepted: 03/02/2024] [Indexed: 03/14/2024] Open
Abstract
N-retinylidene-N-retinylethanolamine (A2E) has been associated with age-related macular degeneration (AMD) physiopathology by inducing cell death, angiogenesis and inflammation in retinal pigmented epithelial (RPE) cells. It was previously thought that the A2E effects were solely mediated via the retinoic acid receptor (RAR)-α activation. However, this conclusion was based on experiments using the RAR "specific" antagonist RO-41-5253, which was found to also be a ligand and partial agonist of the peroxisome proliferator-activated receptor (PPAR)-γ. Moreover, we previously reported that inhibiting PPAR and retinoid X receptor (RXR) transactivation with norbixin also modulated inflammation and angiogenesis in RPE cells challenged in the presence of A2E. Here, using several RAR inhibitors, we deciphered the respective roles of RAR, PPAR and RXR transactivations in an in vitro model of AMD. We showed that BMS 195614 (a selective RAR-α antagonist) displayed photoprotective properties against toxic blue light exposure in the presence of A2E. BMS 195614 also significantly reduced the AP-1 transactivation and mRNA expression of the inflammatory interleukin (IL)-6 and vascular endothelial growth factor (VEGF) induced by A2E in RPE cells in vitro, suggesting a major role of RAR in these processes. Surprisingly, however, we showed that (1) Norbixin increased the RAR transactivation and (2) AGN 193109 (a high affinity pan-RAR antagonist) and BMS 493 (a pan-RAR inverse agonist), which are photoprotective against toxic blue light exposure in the presence of A2E, also inhibited PPARs transactivation and RXR transactivation, respectively. Therefore, in our in vitro model of AMD, several commercialized RAR inhibitors appear to be non-specific, and we propose that the phototoxicity and expression of IL-6 and VEGF induced by A2E in RPE cells operates through the activation of PPAR or RXR rather than by RAR transactivation.
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Affiliation(s)
- Valérie Fontaine
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Thinhinane Boumedine
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Elodie Monteiro
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Mylène Fournié
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Gendre Gersende
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
- Fondation Ophtalmologique Rothschild, 29 rue Manin, 75019 Paris, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Stanislas Veillet
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
| | - René Lafont
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
| | - Mathilde Latil
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
| | - Pierre J. Dilda
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
| | - Serge Camelo
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
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Curcio CA, Kar D, Owsley C, Sloan KR, Ach T. Age-Related Macular Degeneration, a Mathematically Tractable Disease. Invest Ophthalmol Vis Sci 2024; 65:4. [PMID: 38466281 PMCID: PMC10916886 DOI: 10.1167/iovs.65.3.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 02/19/2024] [Indexed: 03/12/2024] Open
Abstract
A progression sequence for age-related macular degeneration onset may be determinable with consensus neuroanatomical nomenclature augmented by drusen biology and eye-tracked clinical imaging. This narrative review proposes to supplement the Early Treatment of Diabetic Retinopathy Study (sETDRS) grid with a ring to capture high rod densities. Published photoreceptor and retinal pigment epithelium (RPE) densities in flat mounted aged-normal donor eyes were recomputed for sETDRS rings including near-periphery rich in rods and cumulatively for circular fovea-centered regions. Literature was reviewed for tissue-level studies of aging outer retina, population-level epidemiology studies regionally assessing risk, vision studies regionally assessing rod-mediated dark adaptation (RMDA), and impact of atrophy on photopic visual acuity. The 3 mm-diameter xanthophyll-rich macula lutea is rod-dominant and loses rods in aging whereas cone and RPE numbers are relatively stable. Across layers, the largest aging effects are accumulation of lipids prominent in drusen, loss of choriocapillary coverage of Bruch's membrane, and loss of rods. Epidemiology shows maximal risk for drusen-related progression in the central subfield with only one third of this risk level in the inner ring. RMDA studies report greatest slowing at the perimeter of this high-risk area. Vision declines precipitously when the cone-rich central subfield is invaded by geographic atrophy. Lifelong sustenance of foveal cone vision within the macula lutea leads to vulnerability in late adulthood that especially impacts rods at its perimeter. Adherence to an sETDRS grid and outer retinal cell populations within it will help dissect mechanisms, prioritize research, and assist in selecting patients for emerging treatments.
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Affiliation(s)
- Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
| | - Deepayan Kar
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
| | - Cynthia Owsley
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
| | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
| | - Thomas Ach
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
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Zhao J, Kim HJ, Montenegro D, Dunaief JL, Sparrow JR. Iron overload and chelation modulates bisretinoid levels in the retina. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1305864. [PMID: 38983013 PMCID: PMC11182296 DOI: 10.3389/fopht.2023.1305864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 12/07/2023] [Indexed: 07/11/2024]
Abstract
Aim Iron dysregulation in conjunction with other disease processes may exacerbate retinal degeneration. We employed models of iron overload and iron chelation to explore the interactions between iron-catalyzed oxidation and photoreactive bisretinoid lipofuscin. Methods The mice were injected intravitreally with ferric ammonium citrate (FAC) or were treated using the iron chelator deferiprone (DFP) from birth to 2 months of age. Short-wavelength fundus autofluorescence (SW-AF) and spectral-domain optical coherence tomography (SD-OCT) scans were acquired. The bisretinoid levels were quantified using ultra performance liquid chromatography (UPLC) and in vivo through quantitative fundus autofluorescence (qAF). In histologic sections, the photoreceptor cell viability was assessed by measuring the thickness of the outer nuclear layer (ONL). Results The levels of bisretinoids, all-trans-retinal dimers, and A2PE were significantly increased in the FAC-injected eyes of C57BL/6J mice. Seven days after FAC injection, hyperautofluorescent foci were visible in fundus autofluorescence (488 nm) images, and in SD-OCT scans, aberrant hyperreflectivity was present in the outer retina and ONL thinning was observed. In FAC-injected Abca4-/- mice with pronounced RPE bisretinoid lipofuscin accumulation, the hyperautofluorescent puncta were more abundant than in the wild-type mice, and the extent of ONL thinning was greater. Conversely, the intravitreal injection of FAC in Mertk-/- mice led to a more modest increase in A2PE after 2 days. In contrast to the effect of iron accumulation, chelation with DFP resulted in significantly increased levels of A2E and A2-GPE and qAF due to the reduced iron-catalyzed oxidation of bisretinoids. In Mertk-/- mice, the A2E level was significantly lower and the ONL area was smaller than in DFP-treated mice. DFP chelation did not impair the visual cycle in BALB/cJ mice. Conclusion Iron accumulation was associated with progressive impairment in photoreceptor cells that was associated with the increased formation of a bisretinoid species known to form in photoreceptor outer segments as a precursor to A2E. Additionally, disease features such as the development of hyperautofluorescence puncta in fundus AF images, hyperreflectivity in the outer retina of SD-OCT scans, and ONL thinning were more pronounced when iron was delivered to Abca4-/- mice with a greater propensity for bisretinoid formation. Higher bisretinoid levels and enhanced qAF are indicative of lesser bisretinoid loss due to oxidation.
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Affiliation(s)
- Jin Zhao
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Hye Jin Kim
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Diego Montenegro
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Josh L Dunaief
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Janet R Sparrow
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
- Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
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Różanowska MB. Lipofuscin, Its Origin, Properties, and Contribution to Retinal Fluorescence as a Potential Biomarker of Oxidative Damage to the Retina. Antioxidants (Basel) 2023; 12:2111. [PMID: 38136230 PMCID: PMC10740933 DOI: 10.3390/antiox12122111] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/05/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Lipofuscin accumulates with age as intracellular fluorescent granules originating from incomplete lysosomal digestion of phagocytosed and autophagocytosed material. The purpose of this review is to provide an update on the current understanding of the role of oxidative stress and/or lysosomal dysfunction in lipofuscin accumulation and its consequences, particularly for retinal pigment epithelium (RPE). Next, the fluorescence of lipofuscin, spectral changes induced by oxidation, and its contribution to retinal fluorescence are discussed. This is followed by reviewing recent developments in fluorescence imaging of the retina and the current evidence on the prognostic value of retinal fluorescence for the progression of age-related macular degeneration (AMD), the major blinding disease affecting elderly people in developed countries. The evidence of lipofuscin oxidation in vivo and the evidence of increased oxidative damage in AMD retina ex vivo lead to the conclusion that imaging of spectral characteristics of lipofuscin fluorescence may serve as a useful biomarker of oxidative damage, which can be helpful in assessing the efficacy of potential antioxidant therapies in retinal degenerations associated with accumulation of lipofuscin and increased oxidative stress. Finally, amendments to currently used fluorescence imaging instruments are suggested to be more sensitive and specific for imaging spectral characteristics of lipofuscin fluorescence.
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Affiliation(s)
- Małgorzata B. Różanowska
- School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Maindy Road, Cardiff CF24 4HQ, Wales, UK;
- Cardiff Institute for Tissue Engineering and Repair (CITER), Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB, Wales, UK
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Anderson DM, Kotnala A, Migas LG, Patterson NH, Tideman L, Cao D, Adhikari B, Messinger JD, Ach T, Tortorella S, Van de Plas R, Curcio CA, Schey KL. Lysolipids are prominent in subretinal drusenoid deposits, a high-risk phenotype in age-related macular degeneration. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1258734. [PMID: 38186747 PMCID: PMC10769005 DOI: 10.3389/fopht.2023.1258734] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Introduction Age related macular degeneration (AMD) causes legal blindness worldwide, with few therapeutic targets in early disease and no treatments for 80% of cases. Extracellular deposits, including drusen and subretinal drusenoid deposits (SDD; also called reticular pseudodrusen), disrupt cone and rod photoreceptor functions and strongly confer risk for advanced disease. Due to the differential cholesterol composition of drusen and SDD, lipid transfer and cycling between photoreceptors and support cells are candidate dysregulated pathways leading to deposit formation. The current study explores this hypothesis through a comprehensive lipid compositional analysis of SDD. Methods Histology and transmission electron microscopy were used to characterize the morphology of SDD. Highly sensitive tools of imaging mass spectrometry (IMS) and nano liquid chromatography tandem mass spectrometry (nLC-MS/MS) in positive and negative ion modes were used to spatially map and identify SDD lipids, respectively. An interpretable supervised machine learning approach was utilized to compare the lipid composition of SDD to regions of uninvolved retina across 1873 IMS features and to automatically discern candidate markers for SDD. Immunohistochemistry (IHC) was used to localize secretory phospholipase A2 group 5 (PLA2G5). Results Among the 1873 detected features in IMS data, three lipid classes, including lysophosphatidylcholine (LysoPC), lysophosphatidylethanolamine (LysoPE) and lysophosphatidic acid (LysoPA) were observed nearly exclusively in SDD while presumed precursors, including phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidic acid (PA) lipids were detected in SDD and adjacent photoreceptor outer segments. Molecular signals specific to SDD were found in central retina and elsewhere. IHC results indicated abundant PLA2G5 in photoreceptors and retinal pigment epithelium (RPE). Discussion The abundance of lysolipids in SDD implicates lipid remodeling or degradation in deposit formation, consistent with ultrastructural evidence of electron dense lipid-containing structures distinct from photoreceptor outer segment disks and immunolocalization of secretory PLA2G5 in photoreceptors and RPE. Further studies are required to understand the role of lipid signals observed in and around SDD.
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Affiliation(s)
| | - Ankita Kotnala
- Department of Biochemistry, Vanderbilt University, Nashville TN
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham AL
| | - Lukasz G. Migas
- Delft Center for Systems and Control (DCSC), Delft University of Technology, Delft, Netherlands
| | | | - Léonore Tideman
- Delft Center for Systems and Control (DCSC), Delft University of Technology, Delft, Netherlands
| | - Dongfeng Cao
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham AL
| | - Bibek Adhikari
- Vision Science Graduate Program, University of Alabama at Birmingham, Birmingham AL
| | - Jeffrey D. Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham AL
| | - Thomas Ach
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
| | - Sara Tortorella
- Molecular Horizon Srl, Via Montelino 30, 06084 Bettona, Perugia, Italy
| | - Raf Van de Plas
- Department of Biochemistry, Vanderbilt University, Nashville TN
- Delft Center for Systems and Control (DCSC), Delft University of Technology, Delft, Netherlands
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham AL
| | - Kevin L. Schey
- Department of Biochemistry, Vanderbilt University, Nashville TN
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10
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Abstract
Over the last half century, the autofluorescence of the metabolic cofactors NADH (reduced nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide) has been quantified in a variety of cell types and disease states. With the spread of nonlinear optical microscopy techniques in biomedical research, NADH and FAD imaging has offered an attractive solution to noninvasively monitor cell and tissue status and elucidate dynamic changes in cell or tissue metabolism. Various tools and methods to measure the temporal, spectral, and spatial properties of NADH and FAD autofluorescence have been developed. Specifically, an optical redox ratio of cofactor fluorescence intensities and NADH fluorescence lifetime parameters have been used in numerous applications, but significant work remains to mature this technology for understanding dynamic changes in metabolism. This article describes the current understanding of our optical sensitivity to different metabolic pathways and highlights current challenges in the field. Recent progress in addressing these challenges and acquiring more quantitative information in faster and more metabolically relevant formats is also discussed.
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Affiliation(s)
- Irene Georgakoudi
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA;
- Genetics, Molecular and Cellular Biology Program, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
| | - Kyle P Quinn
- Department of Biomedical Engineering and the Arkansas Integrative Metabolic Research Center, University of Arkansas, Fayetteville, Arkansas, USA
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11
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Zhang Q, Autterson G, Miller JML. Improved Lipofuscin Models and Quantification of Outer Segment Phagocytosis Capacity in Highly Polarized Human Retinal Pigment Epithelial Cultures. J Vis Exp 2023:10.3791/65242. [PMID: 37125790 PMCID: PMC10306344 DOI: 10.3791/65242] [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] [Indexed: 05/02/2023] Open
Abstract
The daily phagocytosis of photoreceptor outer segments by the retinal pigment epithelium (RPE) contributes to the accumulation of an intracellular aging pigment termed lipofuscin. The toxicity of lipofuscin is well established in Stargardt's disease, the most common inherited retinal degeneration, but is more controversial in age-related macular degeneration (AMD), the leading cause of irreversible blindness in the developed world. Determining lipofuscin toxicity in humans has been difficult, and animal models of Stargardt's have limited toxicity. Thus, in vitro models that mimic human RPE in vivo are needed to better understand lipofuscin generation, clearance, and toxicity. The majority of cell culture lipofuscin models to date have been in cell lines or have involved feeding RPE a single component of the complex lipofuscin mixture rather than fragments/tips of the entire photoreceptor outer segment, which generates a more complete and physiologic lipofuscin model. Described here is a method to induce the accumulation of lipofuscin-like material (termed undigestible autofluorescence material, or UAM) in highly differentiated primary human pre-natal RPE (hfRPE) and induced pluripotent stem cell (iPSC) derived RPE. UAM accumulated in cultures by repeated feedings of ultraviolet light-treated OS fragments taken up by the RPE via phagocytosis. The key ways that UAM approximates and differs from lipofuscin in vivo are also discussed. Accompanying this model of lipofuscin-like accumulation, imaging methods to distinguish the broad autofluorescence spectrum of UAM granules from concurrent antibody staining are introduced. Finally, to assess the impact of UAM on RPE phagocytosis capacity, a new method for quantifying outer segment fragment/tips uptake and breakdown has been introduced. Termed "Total Consumptive Capacity", this method overcomes potential misinterpretations of RPE phagocytosis capacity inherent in classic outer segment "pulse-chase" assays. The models and techniques introduced here can be used to study lipofuscin generation and clearance pathways and putative toxicity.
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Affiliation(s)
- Qitao Zhang
- Kellogg Eye Center, University of Michigan, Ann Arbor
| | | | - Jason M L Miller
- Kellogg Eye Center, University of Michigan, Ann Arbor; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor;
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12
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Quantitative Autofluorescence in Non-Neovascular Age Related Macular Degeneration. Biomedicines 2023; 11:biomedicines11020560. [PMID: 36831096 PMCID: PMC9952913 DOI: 10.3390/biomedicines11020560] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/14/2023] [Indexed: 02/17/2023] Open
Abstract
Quantitative autofluorescence (qAF8) level is a presumed surrogate marker of lipofuscin content in the retina. We investigated the changes in the qAF8 levels in non-neovascular AMD. In this prospective cohort study, Caucasians aged ≥50 years with varying severity of non-neovascular AMD in at least one eye and Snellen visual acuity ≥6/18 were recruited. The qAF8 levels were analysed in the middle eight segments of the Delori pattern (HEYEX software, Heidelberg, Germany). The AMD categories were graded using both the Beckman classification and multimodal imaging (MMI) to include the presence of subretinal drusenoid deposits (SDD). A total of 353 eyes from 231 participants were analyzed. Compared with the age-matched controls, the qAF8 values decreased in the eyes with AMD (adjusted % difference = -19.7% [95% CI -28.8%, -10.4%]; p < 0.001) and across the AMD categories, (adjusted % differences; Early, -13.1% (-24.4%, -1%), p = 0.04; intermediate AMD (iAMD), -22.9% (-32.3%, -13.1%), p < 0.001; geographic atrophy -25.2% (-38.1%, -10.4%), p = 0.002). On MMI, the qAF8 was reduced in the AMD subgroups relative to the controls, (adjusted % differences; Early, -5.8% (-18.9%, 8.3%); p = 0.40; iAMD, -26.7% (-36.2%, -15.6%); p < 0.001; SDD, -23.7% (-33.6%, -12.2%); p < 0.001; atrophy, -26.7% (-39.3%, -11.3%), p = 0.001). The qAF8 levels declined early in AMD and were not significantly different between the severity levels of non-neovascular AMD, suggesting the early and sustained loss of function of the retinal pigment epithelium in AMD.
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13
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Kotnala A, Senthilkumari S, Wu G, Stewart TG, Curcio CA, Halder N, Singh SB, Kumar A, Velpandian T. Retinal Pigment Epithelium in Human Donor Eyes Contains Higher Levels of Bisretinoids Including A2E in Periphery than Macula. Invest Ophthalmol Vis Sci 2022; 63:6. [PMID: 35671050 PMCID: PMC9187938 DOI: 10.1167/iovs.63.6.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose With age, human retinal pigment epithelium (RPE) accumulates bisretinoid fluorophores that may impact cellular function and contribute to age-related macular degeneration (AMD). Bisretinoids are comprised of a central pyridinium, dihydropyridinium, or cyclohexadiene ring. The pyridinium bisretinoid A2E has been extensively studied, and its quantity in the macula has been questioned. Age-changes and distributions of other bisretinoids are not well characterized. We measured levels of three bisretinoids and oxidized A2E in macula and periphery in human donor eyes of different ages. Methods Eyes (N = 139 donors, 61 women and 78 men, aged 40–80 years) were dissected into 8 mm diameter macular and temporal periphery punches. Using liquid chromatography – electrospray ionization – mass spectrometry (LC-ESI-MS) and an authentic synthesized standard, we quantified A2E (ng). Using LC-ESI-MS and a 50-eye-extract of A2E, we semiquantified A2E and 3 other compounds (eye extract equivalent units [EEEUs): A2-glycerophosphoethanolamine (A2GPE), dihydropyridine phosphatidyl ethanolamine (A2DHPE), and monofuranA2E (MFA2E). Results A2E quantities in ng and EEEUs were highly correlated (r = 0.97, P < 0.001). From 262 eyes, 5 to 9-fold higher levels were observed in the peripheral retina than in the macula for all assayed compounds. A2E, A2DHPE, and MFA2E increased with age, whereas A2GPE remained unaffected. No significant right-left or male-female differences were detected. Conclusions Significantly higher levels were observed in the periphery than in the macula for all assayed compounds signifying biologic differences between these regions. Levels of oxidized A2E parallel native A2E and not the distribution of retinal illuminance. Data will assist with the interpretion of clinical trial outcomes of agents targeting bisretinoid-related pathways.
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Affiliation(s)
- Ankita Kotnala
- Ocular Pharmacology & Pharmacy Division, All India Institute of Medical Sciences, New Delhi, India
| | - Srinivasan Senthilkumari
- Department of Ocular Pharmacology, Aravind Medical Research Foundation (AMRF), Dr. G. Venkataswamy Eye Research Institute, #1, Anna Nagar, Madurai -20, Tamilnadu, India
| | - Gong Wu
- Department of Biostatics, Vanderbilt University Medical Centre, Nashville, Tennessee, United States
| | - Thomas G Stewart
- Department of Biostatics, Vanderbilt University Medical Centre, Nashville, Tennessee, United States
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Nabanita Halder
- Ocular Pharmacology & Pharmacy Division, All India Institute of Medical Sciences, New Delhi, India
| | | | - Atul Kumar
- Department of Ophthalmology, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Thirumurthy Velpandian
- Ocular Pharmacology & Pharmacy Division, All India Institute of Medical Sciences, New Delhi, India
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14
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Xu Y, Li D, Su G, Cai S. The effect of A2E on lysosome membrane permeability during blue light-induced human RPEs apoptosis. BMC Ophthalmol 2022; 22:241. [PMID: 35641967 PMCID: PMC9158258 DOI: 10.1186/s12886-022-02464-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 05/24/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To investigate the effect of N-retinyl-N-retinylidene ethanolamine (A2E) on lysosome membrane permeability (LMP) during blue light-induced human retinal pigment epithelium cells (RPEs) apoptosis. METHODS By building an A2E and blue light irradiation inducing RPEs damage model, the CCK-8 assay was used to detect RPEs viability loaded with different concentrations of A2E after different culturing time to determine the optimum A2E loading concentration. And the RPEs fluorescence intensity changes were observed by fluorescence microscopy loaded with different concentration of A2E. The RPEs were divided into four groups randomly: control group, A2E-loaded group, blue light irradiation group, and A2E-loaded + blue light irradiation group. Annexin V-FITC/PI and TUNEL/DAPI methods were used to detect RPEs apoptotic rate. Laser scanning confocal microscopy (LSCM) was used to observe RPEs LMP changes stained by acridine orange (AO) method. RESULTS The CCK-8 result showed a downward trend in cells viability of RPEs loaded with increasing concentration of A2E and extending culturing time. The optimum A2E loading concentration was determined at 25 μmol/L. With increasing A2E loading concentrations, the intensity of fluorescence in RPEs decreased gradually. The RPEs apoptotic rate in blue light irradiation + A2E-loaded group was significantly higher than those in other three groups detected by Annexin V-FITC/PI method, which was similar to TUNEL/DAPI's result. After AO staining, cytoplasmic and nucleolar RNAs emits green fluorescence; lysosomes emit red fluorescence. Through the interference of A2E and blue light on RPEs, red fluorescent leakage from the lysosomes (means LMP increasing) can be observed. The mean red fluorescence intensity was chosen as the statistics indicator to estimate LMP change in RPEs cultured in vitro. Compared with the control group, the red fluorescence intensity decreased in A2E-loaded group, blue light irradiation group, and blue light irradiation + A2E-loaded group. Meanwhile, the mean red fluorescence intensity in blue light irradiation + A2E-loaded group was the lowest. CONCLUSIONS Both A2E-loaded and blue light irradiation could induce human RPEs apoptosis, and the two factors had a synergistic effect. In addition, both A2E and blue light can lead to LMP increasing, which indicated LMP change might be the upstream part in inducing mitochondrion-dependent apoptotic pathway. These data provided evidence that A2E as the most important auto-fluorescence substance in lipofuscin is an initiator of blue light-mediated damage of RPEs and participate in pathogenesis of retinal degenerative diseases in humans.
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Affiliation(s)
- Yan Xu
- Department of Ophthalmology, Affiliated Hospital of Zunyi Medical University, No.149 Dalian Road, Zunyi, 563000, Guizhou, China
- Department of Ophthalmology, HwaMei Hospital, University of Chinese Academy of Sciences, Ningbo No.2 Hospital, Ningbo, Zhejiang, China
| | - Dan Li
- Department of Ophthalmology, Affiliated Hospital of Zunyi Medical University, No.149 Dalian Road, Zunyi, 563000, Guizhou, China
- Department of Ophthalmology, The People's Hospital of Longchang, Neijiang, Sichuan, China
| | - Gang Su
- Department of Ophthalmology, Affiliated Hospital of Zunyi Medical University, No.149 Dalian Road, Zunyi, 563000, Guizhou, China
- Guizhou Eye Hospital, Zunyi, Guizhou, China
- Guizhou Provincial Branch of National Eye Disease Clinical Medicine Research Center, Zunyi, Guizhou, China
- Special Key Laboratory of Ocular Diseases of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou, China
| | - Shanjun Cai
- Department of Ophthalmology, Affiliated Hospital of Zunyi Medical University, No.149 Dalian Road, Zunyi, 563000, Guizhou, China.
- Guizhou Eye Hospital, Zunyi, Guizhou, China.
- Guizhou Provincial Branch of National Eye Disease Clinical Medicine Research Center, Zunyi, Guizhou, China.
- Special Key Laboratory of Ocular Diseases of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou, China.
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15
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Baraas RC, Pedersen HR, Knoblauch K, Gilson SJ. Human Foveal Cone and RPE Cell Topographies and Their Correspondence With Foveal Shape. Invest Ophthalmol Vis Sci 2022; 63:8. [PMID: 35113142 PMCID: PMC8819292 DOI: 10.1167/iovs.63.2.8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose To characterize the association between foveal shape and cone and retinal pigment epithelium (RPE) cell topographies in healthy humans. Methods Multimodal adaptive scanning light ophthalmoscopy and optical coherence tomography (OCT) were used to acquire images of foveal cones, RPE cells, and retinal layers in eyes of 23 healthy participants with normal foveas. Distributions of cone and RPE cell densities were fitted with nonlinear mixed-effects models. A linear mixed-effects model was used to examine the relationship between cone and RPE inter-cell distances and foveal shape as obtained from the OCT scans of retinal thickness. Results The best-fit model to the cone densities was a power function with a nasal–temporal asymmetry. There was a significant linear relationship among cone and RPE cell spacing, foveal shape, and foveal cell topography. The model predictions of the central 10° show that the contributions of both the cones and RPE cells are necessary to account for foveal shape. Conclusions The results indicate that there is a strong relationship between cone and RPE cell spacing and the shape of the human adolescent and adult fovea. This finding adds to the existing evidence of the critical role that the RPE serves in fetal foveal development and through adolescence, possibly via the imposition of constraints on the number and distribution of foveal cones.
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Affiliation(s)
- Rigmor C Baraas
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway
| | - Hilde R Pedersen
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway
| | - Kenneth Knoblauch
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway.,Stem Cell and Brain Research Institute, INSERM U1208, Bron, France.,Université de Lyon, Lyon, France
| | - Stuart J Gilson
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway
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16
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Różanowska MB, Różanowski B. Photodegradation of Lipofuscin in Suspension and in ARPE-19 Cells and the Similarity of Fluorescence of the Photodegradation Product with Oxidized Docosahexaenoate. Int J Mol Sci 2022; 23:ijms23020922. [PMID: 35055111 PMCID: PMC8778276 DOI: 10.3390/ijms23020922] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/07/2022] [Accepted: 01/12/2022] [Indexed: 02/01/2023] Open
Abstract
Retinal lipofuscin accumulates with age in the retinal pigment epithelium (RPE), where its fluorescence properties are used to assess retinal health. It was observed that there is a decrease in lipofuscin fluorescence above the age of 75 years and in the early stages of age-related macular degeneration (AMD). The purpose of this study was to investigate the response of lipofuscin isolated from human RPE and lipofuscin-laden cells to visible light, and to determine whether an abundant component of lipofuscin, docosahexaenoate (DHA), can contribute to lipofuscin fluorescence upon oxidation. Exposure of lipofuscin to visible light leads to a decrease in its long-wavelength fluorescence at about 610 nm, with a concomitant increase in the short-wavelength fluorescence. The emission spectrum of photodegraded lipofuscin exhibits similarity with that of oxidized DHA. Exposure of lipofuscin-laden cells to light leads to a loss of lipofuscin granules from cells, while retaining cell viability. The spectral changes in fluorescence in lipofuscin-laden cells resemble those seen during photodegradation of isolated lipofuscin. Our results demonstrate that fluorescence emission spectra, together with quantitation of the intensity of long-wavelength fluorescence, can serve as a marker useful for lipofuscin quantification and for monitoring its oxidation, and hence useful for screening the retina for increased oxidative damage and early AMD-related changes.
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Affiliation(s)
- Małgorzata B. Różanowska
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, UK
- Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Cardiff CF10 3NB, UK
- Correspondence: ; Tel.: +44-2920875057
| | - Bartosz Różanowski
- Institute of Biology, Pedagogical University of Kraków, 30-084 Kraków, Poland;
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17
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Zhang D, Robinson K, Washington I. C20D3-Vitamin A Prevents Retinal Pigment Epithelium Atrophic Changes in a Mouse Model. Transl Vis Sci Technol 2021; 10:8. [PMID: 34878528 PMCID: PMC8662574 DOI: 10.1167/tvst.10.14.8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose This study aimed to evaluate the contribution of vitamin A dimerization to retinal pigment epithelium (RPE) atrophic changes. Leading causes of irreversible blindness, including Stargardt disease and age-related macular degeneration (AMD), occur as a result of atrophic changes in RPE. The cause of the RPE atrophic changes is not apparent. During the vitamin A cycle, vitamin A dimerizes, leading to vitamin A cycle byproducts, such as vitamin A dimers, in the RPE. Methods To study the consequence of vitamin A dimerization to RPE atrophic changes, we used a rodent model with accelerated vitamin A dimerization, Abca4−/−/Rdh8−/− mice, and the vitamin A analog C20D3-vitamin A to selectively ameliorate the accelerated rate of vitamin A dimerization. Results We show that ameliorating the rate of vitamin A dimerization with C20D3-vitamin A mitigates pathological changes observed in the prodromal phase of the most prevalent retinal degenerative diseases, including fundus autofluorescence changes, dark adaptation delays, and signature RPE atrophic changes. Conclusions Data demonstrate that the dimerization of vitamin A during the vitamin A cycle is sufficient alone to cause the prerequisite RPE atrophic changes thought to be responsible for the leading causes of irreversible blindness and that correcting the dimerization rate with C20D3-vitamin A may be sufficient to prevent the RPE atrophic changes. Translational Relevance Preventing the dimerization of vitamin A with the vitamin A analog C20D3-vitamin A may be sufficient to alter the clinical course of the most prevalent forms of blindness, including Stargardt disease and age-related macular degeneration (AMD).
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Affiliation(s)
- Dan Zhang
- Columbia University Medical Center, Ophthalmology, New York, NY, USA
| | - Kiera Robinson
- Columbia University Medical Center, Ophthalmology, New York, NY, USA
| | - Ilyas Washington
- Columbia University Medical Center, Ophthalmology, New York, NY, USA.,biOOrg3.14, Buffalo, WY, USA
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18
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Schultz R, Schwanengel L, Klemm M, Meller D, Hammer M. Spectral fundus autofluorescence peak emission wavelength in ageing and AMD. Acta Ophthalmol 2021; 100:e1223-e1231. [PMID: 34850573 DOI: 10.1111/aos.15070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/26/2021] [Accepted: 11/19/2021] [Indexed: 01/18/2023]
Abstract
PURPOSE To investigate the spectral characteristics of fundus autofluorescence (FAF) in AMD patients and controls. METHODS Fundus autofluorescence spectral characteristics was described by the peak emission wavelength (PEW) of the spectra. Peak emission wavelength (PEW) was derived from the ratio of FAF recordings in two spectral channels at 500-560 nm and 560-720 nm by fluorescence lifetime imaging ophthalmoscopy. The ratio of FAF intensity in both channels was related to PEW by a calibration procedure. Peak emission wavelength (PEW) measurements were done in 44 young (mean age: 24.0 ± 3.8 years) and 18 elderly (mean age: 67.5 ± 10.2 years) healthy subjects as well as 63 patients with AMD (mean age: 74.0 ± 7.3 years) in each pixel of a 30° imaging field. The values were averaged over the central area, the inner and the outer ring of the ETDRS grid. RESULTS There was no significant difference between PEW in young and elderly controls. However, PEW was significantly shorter in AMD patients (ETDRS grid centre: 571 ± 26 nm versus 599 ± 17 nm for elderly controls, inner ring: 596 ± 17 nm versus 611 ± 11 nm, outer ring: 602 ± 16 nm versus 614 ± 11 nm). After a mean follow-up time of 50.8 ± 10.8 months, the PEW in the patients decreased significantly by 9 ± 19 nm in the inner ring of the grid. Patients, showing progression to atrophic AMD in the follow up, had significantly (p ≤ 0.018) shorter PEW at baseline than non-progressing patients. CONCLUSIONS Peak emission wavelength (PEW) is related to AMD pathology and might be a diagnostic marker in AMD. Possibly, a short PEW can predict progression to retinal and/or pigment epithelium atrophy.
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Affiliation(s)
- Rowena Schultz
- Department of Ophthalmology University Hospital Jena Jena Germany
| | | | - Matthias Klemm
- Institute of Biomedical Engineering and Informatics Technical Univ. Ilmenau Ilmenau Germany
| | - Daniel Meller
- Department of Ophthalmology University Hospital Jena Jena Germany
| | - Martin Hammer
- Department of Ophthalmology University Hospital Jena Jena Germany
- Center for Medical Optics and Photonics Univ. of Jena Jena Germany
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19
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Abstract
Light has a crucial role in the visual process. For nonvisible radiation in the short-wave spectrum, there are natural mechanisms that protect the human retina from damaging ultraviolet (UV) radiation. Here, the dose (= energy) makes the poison. Damage caused by UV light mainly affects the outer retina, particularly the photoreceptors and the retinal pigment epithelium. While retinal damage due to increased UV radiation exposure can potentially still occur up to the age of 20, in adulthood, exposure of the retina to UV radiation can no longer be assumed, due to decreasing transmission properties of the natural lens. The natural lens, modern intraocular lenses, and wearing of sunglasses with appropriate filter function, particularly in childhood and adolescence, provide a relevant reduction in UV radiation exposure of the retina.
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Affiliation(s)
| | - Thomas Ach
- Augenklinik, Universitätsklinikum Bonn, Venusberg-Campus 1, 53127, Bonn, Deutschland.
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20
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A2E-induced inflammation and angiogenesis in RPE cells in vitro are modulated by PPAR-α, -β/δ, -γ, and RXR antagonists and by norbixin. Aging (Albany NY) 2021; 13:22040-22058. [PMID: 34544906 PMCID: PMC8507260 DOI: 10.18632/aging.203558] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 09/03/2021] [Indexed: 12/15/2022]
Abstract
N-retinylidene-N-retinylethanolamine (A2E) plays a central role in age-related macular degeneration (AMD) by inducing angiogenesis and inflammation. A2E effects are mediated at least partly via the retinoic acid receptor (RAR)-α. Here we show that A2E binds and transactivates also peroxisome proliferator-activated receptors (PPAR) and retinoid X receptors (RXR). 9’-cis-norbixin, a di-apocarotenoid is also a ligand of these nuclear receptors (NR). Norbixin inhibits PPAR and RXR transactivation induced by A2E. Moreover, norbixin reduces protein kinase B (AKT) phosphorylation, NF-κB and AP-1 transactivation and mRNA expression of the inflammatory interleukins (IL) -6 and -8 and of vascular endothelial growth factor (VEGF) enhanced by A2E. By contrast, norbixin increases matrix metalloproteinase 9 (MMP9) and C-C motif chemokine ligand 2 (CCL2) mRNA expression in response to A2E. Selective PPAR-α, -β/δ and –γ antagonists inhibit the expression of IL-6 and IL-8 while only the antagonist of PPAR-γ inhibits the transactivation of NF-κB following A2E exposure. In addition, a cocktail of all three PPARs antagonists and also HX531, an antagonist of RXR reproduce norbixin effects on inflammation. Altogether, A2E’s deleterious biological effects could be inhibited through PPAR and RXR regulation. Moreover, the modulation of these NR by norbixin may open new avenues for the treatment of AMD.
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21
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Chen L, Messinger JD, Ferrara D, Freund KB, Curcio CA. Stages of Drusen-Associated Atrophy in Age-Related Macular Degeneration Visible via Histologically Validated Fundus Autofluorescence. Ophthalmol Retina 2021; 5:730-742. [PMID: 33217617 PMCID: PMC9749404 DOI: 10.1016/j.oret.2020.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/29/2020] [Accepted: 11/12/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To determine histologic correlates for stages of drusen-associated atrophy observed with fundus autofluorescence (FAF) and color fundus photography (CFP), of eyes with advanced age-related macular degeneration (AMD). DESIGN Case study and clinicopathologic correlation. PARTICIPANT A white woman with AMD findings of inactive subretinal fibrosis (right eye) and untreated nonexudative type 1 macular neovascularization (left eye) was followed for 9 years before death at 90 years of age. METHODS Eyes preserved 6.25 hours after death were postfixed in osmium tannic acid paraphenylenediamine and were prepared for submicrometer epoxy resin sections (115 and 90 from the right and left eye, respectively), with 19 aligned to clinical B-scans. Drusen visible by CFP at the last visit were assigned to 4 stages of FAF: stage 1, isoautofluorescence; stage 2, mildly uniform hyperautofluorescence; stage 3, a ring of hyperautofluorescence around a center of the hypoautofluorescence; and stage 4, uniform hypoautofluorescence. MAIN OUTCOME MEASURES Light microscopic morphologic features at known FAF stages, including druse size, druse contents, and changes in overlying retinal pigment epithelium (RPE), photoreceptors, and external limiting membrane (ELM). RESULTS Histologic examination of 166 drusen demonstrated that stage 1 isoautofluorescent drusen were visible on CFP. Hyperautofluorescence in stage 2 corresponded to short photoreceptors and complete coverage by RPE. Hypoautofluorescence in stages 3 and 4 corresponded to different extents of RPE atrophy (RPE gap and no RPE, respectively). Of stage 4 drusen, 67% showed no outer nuclear layer (ONL) and an undetectable ELM. Stage 4 included a high proportion of refractile drusen (82%) with many calcific nodules, visible on CFP. CONCLUSIONS We present the first direct clinicopathologic correlation for FAF imaging of drusen-associated atrophy. Our data support 4 FAF stages of drusen-associated atrophy. Stage 2 is the earliest detected stage in which loss of screening by photoreceptor photopigment contributes to uniform hyperautofluorescence. Stages 3 and 4 comport with incomplete RPE and outer retinal atrophy as defined by the Classification of Atrophy Meetings group. Loss of RPE, ONL, and ELM in stage 4 indicates that atrophy can begin over individual drusen. Findings will help the identification of new therapeutic approaches and clinical study end points.
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Affiliation(s)
- Ling Chen
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham Alabama, USA,The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, and Chongqing Eye Institute, Chongqing, China
| | - Jeffrey D. Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham Alabama, USA
| | | | - K. Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, NY, USA,LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, NY, USA,Department of Ophthalmology, New York University School of Medicine, New York, NY, USA,Columbia University College of Physicians and Surgeons, Harkness Eye Institute, New York, NY, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham Alabama, USA,Corresponding Address: Christine A. Curcio, PhD; Department of Ophthalmology and Visual Sciences; EyeSight Foundation of Alabama Vision Research Laboratories; 1670 University Boulevard Room 360; University of Alabama School of Medicine; Birmingham AL 35294-0099;
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INVESTIGATING A GROWTH PREDICTION MODEL IN ADVANCED AGE-RELATED MACULAR DEGENERATION WITH SOLITARY GEOGRAPHIC ATROPHY USING QUANTITATIVE AUTOFLUORESCENCE. Retina 2021; 40:1657-1664. [PMID: 31584560 DOI: 10.1097/iae.0000000000002653] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE To investigate geographic atrophy (GA) progression using quantitative autofluorescence (qAF) in eyes with solitary GA. METHODS Forty-three eyes of 26 patients (age 79.7 ± 7.2 years; 28 women; 16 pseudophakic) underwent spectral-domain optical coherence tomography and qAF imaging at baseline and after 12 months. The junctional zone (AJZ) and a nonaffected 300-µm-wide control area (AC) were delineated on spectral-domain optical coherence tomography scans and transferred to the qAF image. Linear mixed models were calculated to investigate the association between GA progression and qAF, age, and baseline GA area. Mixed model analyses of variance were used to investigate differences in qAF between areas. RESULTS Quantitative autofluorescence of the three inferior sections of both the AJZ (P = 0.028; P = 0.014 and P = 0.032) and the AC (P = 0.043; P = 0.02 and P = 0.028) were significantly associated with GA progression after 12 months. However, qAF measurements were not associated with GA progression in the overall model (P > 0.05). Mean qAF was significantly lower in the AJZ and growth area (AG12) than in the AC (both P ≤ 0.001). CONCLUSION The authors report a statistically significant association between GA growth area and qAF measurements at specific retinal locations and a significant difference in qAF between the GA border and unaffected areas outside the lesion. Quantitative autofluorescence measurements may be limitedly useful for predicting GA progression.
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Călin EF, Patoni Popescu SI, Coman Cernat CC, Patoni C, Popescu MN, Mușat O. Lipofuscin: a key compound in ophthalmic practice. Rom J Ophthalmol 2021; 65:109-113. [PMID: 34179573 PMCID: PMC8207864 DOI: 10.22336/rjo.2021.23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Lipofuscin is an intracellular aging pigment with fluorescent properties, found in retinal pigment epithelium cells of the eye. It is the main fluorophore used in fundus autofluorescence imaging techniques to diagnose, describe, and follow retinal disease. Lipofuscin forms by incomplete lysosomal degradation of cellular material previously subjected to oxidative changes. A2E is the most studied fluorescent component of lipofuscin, but most of its composition remains unknown. Lipofuscin is photoreactive, generating reactive oxygen species, which may explain its role in disease development. Further knowledge is needed concerning lipofuscin genesis, biochemical composition, fluorescent compounds, and role in pathogenesis of retinal degenerative disease.
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Affiliation(s)
- Edward Florian Călin
- Department of Ophthalmology, "Dr. Carol Davila" Central Military Emergency University Hospital, Bucharest, Romania
| | | | - Corina Cristina Coman Cernat
- Department of Ophthalmology, "Dr. Carol Davila" Central Military Emergency University Hospital, Bucharest, Romania.,"Victor Babeş" University of Medicine and Pharmacy, Timișoara, Romania
| | - Cristina Patoni
- Department of Gastroenterology, "Dr. Carol Davila" Central Military Emergency University Hospital, Bucharest, Romania
| | | | - Ovidiu Mușat
- Department of Ophthalmology, "Dr. Carol Davila" Central Military Emergency University Hospital, Bucharest, Romania
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24
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Reiter GS, Hacker V, Told R, Schranz M, Krotka P, Schlanitz FG, Sacu S, Pollreisz A, Schmidt-Erfurth U. LONGITUDINAL CHANGES IN QUANTITATIVE AUTOFLUORESCENCE DURING PROGRESSION FROM INTERMEDIATE TO LATE AGE-RELATED MACULAR DEGENERATION. Retina 2021; 41:1236-1241. [PMID: 33084296 DOI: 10.1097/iae.0000000000002995] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE To prospectively investigate the development of quantitative autofluorescence (qAF) during progression from intermediate to late age-related macular degeneration (AMD). METHODS Quantitative autofluorescence images from patients with intermediate AMD were acquired every three months with a Spectralis HRA + OCT (Heidelberg Engineering, Heidelberg, Germany) using a built-in autofluorescence reference. The association between changes in longitudinal qAF and progression toward late AMD was assessed using Cox regression models with time-dependent covariates. RESULTS One hundred and twenty-one eyes of 71 patients were included, and 653 qAF images were acquired. Twenty-one eyes of 17 patients converted to late AMD (median follow-up: 21 months; 12 eyes: atrophic AMD; nine eyes: neovascular AMD). The converting patients' mean age was 74.6 ± 4.4 years. Eleven eyes in the converting group (52.4%) were pseudophakic. The presence of an intraocular lens did not affect the qAF regression slopes (P > 0.05). The median change for atrophic AMD was -2.34 qAF units/3 months and 0.78 qAF units/3 months for neovascular AMD. A stronger decline in qAF was significantly associated with an increased risk of developing atrophic AMD (hazard ratio = 1.022, P < 0.001). This association, however, was not present in the group progressing toward neovascular AMD (hazard ratio = 1.001, P = 0.875). CONCLUSION The qAF signal declines with progression to atrophy, contrary to developing neovascularization. Quantitative autofluorescence may allow identification of patients at risk of progressing to late AMD and benefits individualized patient care in intermediate AMD.
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Affiliation(s)
- Gregor S Reiter
- Department of Ophthalmology and Optometry, Christian Doppler Laboratory for Ophthalmic Image Analysis, Vienna Reading Center, Medical University of Vienna, Vienna, Austria
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Valentin Hacker
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Reinhard Told
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Markus Schranz
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Pavla Krotka
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Ferdinand G Schlanitz
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Stefan Sacu
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Andreas Pollreisz
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Ursula Schmidt-Erfurth
- Department of Ophthalmology and Optometry, Christian Doppler Laboratory for Ophthalmic Image Analysis, Vienna Reading Center, Medical University of Vienna, Vienna, Austria
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
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25
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Butler JM, Supharattanasitthi W, Yang YC, Paraoan L. RNA-seq analysis of ageing human retinal pigment epithelium: Unexpected up-regulation of visual cycle gene transcription. J Cell Mol Med 2021; 25:5572-5585. [PMID: 33934486 PMCID: PMC8184696 DOI: 10.1111/jcmm.16569] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/07/2021] [Accepted: 04/09/2021] [Indexed: 02/06/2023] Open
Abstract
Ageing presents adverse effects on the retina and is the primary risk factor for age‐related macular degeneration (AMD). We report the first RNA‐seq analysis of age‐related transcriptional changes in the human retinal pigment epithelium (RPE), the primary site of AMD pathogenesis. Whole transcriptome sequencing of RPE from human donors ranging in age from 31 to 93 reveals that ageing is associated with increasing transcription of main RPE‐associated visual cycle genes (including LRAT, RPE65, RDH5, RDH10, RDH11; pathway enrichment BH‐adjusted P = 4.6 × 10−6). This positive correlation is replicated in an independent set of 28 donors and a microarray dataset of 50 donors previously published. LRAT expression is positively regulated by retinoid by‐products of the visual cycle (A2E and all‐trans‐retinal) involving modulation by retinoic acid receptor alpha transcription factor. The results substantiate a novel age‐related positive feedback mechanism between accumulation of retinoid by‐products in the RPE and the up‐regulation of visual cycle genes.
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Affiliation(s)
- Joe M Butler
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Wasu Supharattanasitthi
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Yit C Yang
- Department of Ophthalmology, Wolverhampton Eye Infirmary, New Cross Hospital, Wolverhampton, UK
| | - Luminita Paraoan
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
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26
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Deitch I, Ferenchak K, Miller JB. Quantitative autofluorescence: Review of Current Technical Aspects and Applications in Chorioretinal Disease. Semin Ophthalmol 2021; 36:346-350. [PMID: 33818290 DOI: 10.1080/08820538.2021.1908570] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Purpose: In this review we discuss the broad clinical application of qAF and provide a descriptive summary of the phenotypic findings of different chorioretinal pathologies.Background: Quantitative Fundus autofluorescence (qAF) is a novel developing technology that can aid in diagnosis and longitudinal disease monitoring by measuring and comparing autofluorescence intensities. Fundus autofluorescence (FAF) is a noninvasive imaging method that creates a density map of the fluorophores of the ocular fundus and provides both functional and topographic anatomic information about retinal cells. Fluorophores are molecules that have the ability to temporarily absorb irradiated light, and emit a small amount of light of a different wavelength. Different endogenous fluorophores can be found in the ocular fundus. Changes in accumulation of retinal fluorophores usually indicate retinal pathology and create characteristic patterns of hyper-autofluorescence and hypo-autofluorescence that help establish a diagnosis.Conclusion: qAF allows a safe non-invasive visualization of the retina, enables a standard for AF intensities comparison and aids to the understanding of the genotype-phenotype correlations.
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Affiliation(s)
- Iris Deitch
- Department of Ophthalmology, Retina Service Mass Eye and Ear Harvard Medical School, Boston, MA, United States
| | - Kevin Ferenchak
- Department of Ophthalmology, Retina Service Mass Eye and Ear Harvard Medical School, Boston, MA, United States
| | - John B Miller
- Department of Ophthalmology, Retina Service Mass Eye and Ear Harvard Medical School, Boston, MA, United States
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27
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Ando S, Hashida N, Yamashita D, Kawabata T, Asao K, Kawasaki S, Sakurai K, Yoshimori T, Nishida K. Rubicon regulates A2E-induced autophagy impairment in the retinal pigment epithelium implicated in the pathology of age-related macular degeneration. Biochem Biophys Res Commun 2021; 551:148-154. [PMID: 33740621 DOI: 10.1016/j.bbrc.2021.02.148] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 02/28/2021] [Indexed: 12/24/2022]
Abstract
Waste product deposition and light stress in the retinal pigment epithelium (RPE) are crucial factors in the pathogenesis of various retinal degenerative diseases, including age-related macular degeneration (AMD), a leading cause of vision loss in elderly individuals worldwide. Given that autophagy in the RPE suppresses waste accumulation, determining the molecular mechanism by which autophagy is compromised in degeneration is necessary. Using polarized human RPE sheets, we found that bis-retinoid N-retinyl-N-retinylidene ethanolamine (A2E), a major toxic fluorophore of lipofuscin, causes significant impairment of autophagy and the simultaneous upregulation of Rubicon, a negative regulator of autophagy. Importantly, this impairment was reversed in Rubicon-specific siRNA-treated RPE sheets. In a retinal functional analysis using electroretinograms (ERGs), mice with the RPE-specific deletion of Rubicon showed no significant differences from control cre-expressing mice but presented partially but significantly enhanced amplitudes compared with Atg7 knockout mice. We also found that an inflammatory reaction in the retina in response to chronic blue light irradiation was alleviated in mice with the RPE-specific deletion of Rubicon. In summary, we propose that upregulating basal autophagy by targeting Rubicon is beneficial for protecting the RPE from functional damage with ageing and the inflammatory reaction caused by light-induced cellular stress.
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Affiliation(s)
- Satoru Ando
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Ako Research Institute, Otsuka Pharmaceutical Co., Ltd, Ako, Hyogo, Japan
| | - Noriyasu Hashida
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
| | - Daisuke Yamashita
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Ako Research Institute, Otsuka Pharmaceutical Co., Ltd, Ako, Hyogo, Japan
| | - Tsuyoshi Kawabata
- Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Nagasaki, Japan
| | - Kazunobu Asao
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Satoshi Kawasaki
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Kazushi Sakurai
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Ako Research Institute, Otsuka Pharmaceutical Co., Ltd, Ako, Hyogo, Japan
| | - Tamotsu Yoshimori
- Department of Genetics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Kohji Nishida
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka, Japan.
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Abstract
PURPOSE To correlate drusen morphology and outer retinal status with autofluorescence (AF) imaging in patients with intermediate age-related macular degeneration. METHODS Drusen type and morphology were analyzed using color fundus photography and spectral-domain optic coherence tomography, whereas fundus AF was used for drusen AF evaluation. Additional structural changes on spectral-domain optic coherence tomography, such as disruption of external limiting membrane, ellipsoid zone, and retinal pigment epithelium/Bruch membrane complex, as well as the presence of choroidal hypertransmission at correspondent locations were also evaluated and correlated with fundus AF findings. Spearman's correlation coefficient was used to analyze the correlation between spectral-domain optic coherence tomography morphological characteristics of drusen and AF appearance of the corresponding drusen. Strength of correlation was calculated (r), and a P value < 0.05 was considered statistically significant. RESULTS Two hundred and twenty-eight drusen from 53 eyes of 53 patients were analyzed, 130 soft drusen (57.02%) and 98 cuticular drusen (42.98%). Sixty percent of the drusen were isoautofluorescent (n = 136), 35% hyperautofluorescent (n = 80), and 5% hypoautofluorescent (n = 12). We found positive correlation between drusen AF and hyperreflective foci (r = 0.4). Outer retinal layers morphology (external limiting membrane and ellipsoid zone status and hypertransmission) also correlates with autofluorescent findings (r = 0.3). CONCLUSION Multimodal imaging reveals a broad spectrum of ultrastructural changes, which may reflect different stages in the evolution of drusen. Our results suggest that drusen morphological characteristics and autofluorescent findings are correlated but other factors or cofactors may be involved. The described correlations will help us understand new progression biomarkers of nonexudative age-related macular degeneration.
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Kim HJ, Sparrow JR. Bisretinoid phospholipid and vitamin A aldehyde: shining a light. J Lipid Res 2021; 62:100042. [PMID: 32371567 PMCID: PMC7933493 DOI: 10.1194/jlr.tr120000742] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/29/2020] [Indexed: 12/17/2022] Open
Abstract
Vitamin A aldehyde covalently bound to opsin protein is embedded in a phospholipid-rich membrane that supports photon absorption and phototransduction in photoreceptor cell outer segments. Following absorption of a photon, the 11-cis-retinal chromophore of visual pigment in photoreceptor cells isomerizes to all-trans-retinal. To maintain photosensitivity 11-cis-retinal must be replaced. At the same time, however, all-trans-retinal has to be handled so as to prevent nonspecific aldehyde activity. Some molecules of retinaldehyde upon release from opsin are efficiently reduced to retinol. Other molecules are released into the lipid phase of the disc membrane where they form a conjugate [N-retinylidene-PE (NRPE)] through a Schiff base linkage with PE. The reversible formation of NRPE serves as a transient sink for retinaldehyde that is intended to return retinaldehyde to the visual cycle. However, if instead of hydrolyzing to PE and retinaldehyde, NRPE reacts with a second molecule of retinaldehyde, a synthetic pathway is initiated that leads to the formation of multiple species of unwanted bisretinoid fluorophores. We report on recently identified members of the bisretinoid family, some of which differ with respect to the acyl chains associated with the glycerol backbone. We discuss processing of the lipid moieties of these fluorophores in lysosomes of retinal pigment epithelial cells, their fluorescence characters, and new findings related to light- and iron-associated oxidation of bisretinoids.
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Affiliation(s)
- Hye Jin Kim
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY, USA.
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30
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Chen L, Messinger JD, Ferrara D, Freund KB, Curcio CA. Fundus Autofluorescence in Neovascular Age-Related Macular Degeneration: A Clinicopathologic Correlation Relevant to Macular Atrophy. Ophthalmol Retina 2021; 5:1085-1096. [PMID: 33540168 DOI: 10.1016/j.oret.2021.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/16/2021] [Accepted: 01/20/2021] [Indexed: 01/06/2023]
Abstract
PURPOSE Macular atrophy (MA) of retinal pigment epithelium (RPE) and photoreceptors leads to vision loss in neovascular age-related macular degeneration (nAMD) despite successful treatment with antiangiogenic agents. To enhance understanding of MA, fortify the cellular basis of fundus autofluorescence (FAF) imaging, and inform management of nAMD, we performed histologic analysis of an eye with multimodal clinical imaging and apparent prior exudation due to nAMD. DESIGN Case study and clinicopathologic correlation. PARTICIPANT A White woman in whom age-related macular degeneration (AMD) findings of inactive subretinal fibrosis (right eye) were followed for 9 years using FAF and OCT, with no detectable subretinal fluid or other recurrent exudation and no intravitreal injections before her death at age 90 years. METHODS The right eye was preserved 6.25 hours after death, postfixed in osmium tannic acid paraphenylenediamine, and prepared for submicrometer epoxy resin sections (n = 115), with 19 matched to clinical OCT B-scans. MAIN OUTCOME MEASURES Light microscopic morphology of a hyperautofluorescent (hyperFAF) area due to prior exudation ("floodplain" hyperFAF), hypoautofluorescent (hypoFAF) spots of MA, and areas of unremarkable FAF. RESULTS Floodplain hyperFAF was visible throughout the 9 years of follow-up, with several hypoFAF atrophic spots expanding within it over time. The hyperFAF pattern corresponded to outer retinal atrophy (ORA) on OCT and photoreceptor loss over dysmorphic yet continuous RPE in histology. The hypoFAF spots inside the floodplain corresponded to complete RPE and outer retinal atrophy (cRORA) on OCT and loss of both photoreceptors and RPE in histology. In contrast, areas of unremarkable FAF showed continuous RPE accompanied by full-length photoreceptors and a thick outer nuclear layer. CONCLUSIONS This direct clinicopathologic correlation for FAF imaging is the first for nAMD. Fundus autofluorescence is a projection image that involves optical signal modulation by photoreceptors as well as emission signal sources in RPE. Hyperautofluorescence due to an exudative floodplain signifies loss of photoreceptors over continuous RPE. Hypoautofluorescence in MA signifies loss of both cell layers. For maximal value, fundus autofluorescence imaging should be interpreted with the multilayer perspective provided by OCT. Prevention of exudation in nAMD may preserve photoreceptors.
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Affiliation(s)
- Ling Chen
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, and Chongqing Eye Institute, Chongqing, China; Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Jeffrey D Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | | | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, New York; LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York; Department of Ophthalmology, New York University School of Medicine, New York, New York; Columbia University College of Physicians and Surgeons, Harkness Eye Institute, New York, New York
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama.
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Comment and response to the article "The clinical relevance of visualizing the peripheral retina"by Nicola Quinn, Lajos Csincsik, Erin Flynn, Christine A. Curcio, Szilard Kiss, SriniVas R. Sadda, Ruth Hogg, Tunde Peto & Imre Lengyel. Prog Retin Eye Res 2021; 83:100939. [PMID: 33453363 DOI: 10.1016/j.preteyeres.2020.100939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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32
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Anderson DMG, Messinger JD, Patterson NH, Rivera ES, Kotnala A, Spraggins JM, Caprioli RM, Curcio CA, Schey KL. Lipid Landscape of the Human Retina and Supporting Tissues Revealed by High-Resolution Imaging Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:2426-2436. [PMID: 32628476 PMCID: PMC8161663 DOI: 10.1021/jasms.0c00119] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The human retina provides vision at light levels ranging from starlight to sunlight. Its supporting tissues regulate plasma-delivered lipophilic essentials for vision, including retinoids. The macula is an anatomic specialization for high-acuity and color vision that is also vulnerable to prevalent blinding diseases. The retina's exquisite architecture comprises numerous cell types that are aligned horizontally, yielding structurally distinct cell, synaptic, and vascular layers that are visible in histology and in diagnostic clinical imaging. MALDI imaging mass spectrometry (IMS) is now capable of uniting low micrometer spatial resolution with high levels of chemical specificity. In this study, a multimodal imaging approach fortified with accurate multi-image registration was used to localize lipids in human retina tissue at laminar, cellular, and subcellular levels. Multimodal imaging results indicate differences in distributions and abundances of lipid species across and within single cell types. Of note are distinct localizations of signals within specific layers of the macula. For example, phosphatidylethanolamine and phosphatidylinositol lipids were localized to central RPE cells, whereas specific plasmalogen lipids were localized to cells of the perifoveal RPE and Henle fiber layer. Subcellular compartments of photoreceptors were distinguished by PE(20:0_22:5) in the outer nuclear layer, PE(18:0_22:6) in outer and inner segments, and cardiolipin CL(70:5) in the mitochondria-rich inner segments. Several lipids, differing by a single double bond, have markedly different distributions between the central fovea and the ganglion cell and inner nuclear layers. A lipid atlas, initiated in this study, can serve as a reference database for future examination of diseased tissues.
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Affiliation(s)
- David M G Anderson
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Jeffrey D Messinger
- Department of Ophthalmology and Visual Science, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Nathan H Patterson
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Emilio S Rivera
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Ankita Kotnala
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department of Ophthalmology and Visual Science, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Jeffrey M Spraggins
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Richard M Caprioli
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Christine A Curcio
- Department of Ophthalmology and Visual Science, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Kevin L Schey
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
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Xu A, Chen C. Clinical application of ultra-widefield fundus autofluorescence. Int Ophthalmol 2020; 41:727-741. [PMID: 33040254 DOI: 10.1007/s10792-020-01609-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 10/01/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE To review the basic principles of ultra-widefield fundus autofluorescence (UWF-FAF) and discuss its clinical application for a variety of retinal and choroidal disorders. METHODS A systematic review of the PubMed database was performed using the search terms "ultra-widefield," "autofluorescence," "retinal disease" and "choroidal disease." RESULTS UWF-FAF imaging is a recently developed noninvasive retinal imaging modality with a wide imaging range that can locate peripheral fundus lesions that traditional fundus autofluorescence cannot. Multiple commercially available ultra-widefield imaging systems, including Heidelberg Spectralis and Optomap Ultra-Widefield systems, are available to the clinician. Imaging by UWF-FAF is more comprehensive; it can reflect the content and distribution of the predominant ocular fluorophore in retinal pigment epithelial cells and evaluate the metabolic status of RPE of various retinal and choroidal disorders. CONCLUSION UWF-FAF can detect abnormalities that traditional fundus autofluorescence cannot; therefore, it can be used to better elucidate disease pathogenesis, analyze genotype-phenotype correlations, diagnose and monitor disease.
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Affiliation(s)
- Amin Xu
- Department of Ophthalmology of Renmin Hospital of Wuhan University, No238, Jiefang Road, Wuhan, 430060, Hubei, China
| | - Changzheng Chen
- Department of Ophthalmology of Renmin Hospital of Wuhan University, No238, Jiefang Road, Wuhan, 430060, Hubei, China.
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34
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Sun S, Cai B, Li Y, Su W, Zhao X, Gong B, Li Z, Zhang X, Wu Y, Chen C, Tsang SH, Yang J, Li X. HMGB1 and Caveolin-1 related to RPE cell senescence in age-related macular degeneration. Aging (Albany NY) 2020; 11:4323-4337. [PMID: 31284269 PMCID: PMC6660032 DOI: 10.18632/aging.102039] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 06/20/2019] [Indexed: 01/09/2023]
Abstract
Accumulation of lipofuscin in the retinal pigment epithelium (RPE) is considered a major cause of RPE dysfunction and senescence in age-related macular degeneration (AMD), and N-retinylidene-N-retinylethanolamine (A2E) is the main fluorophore identified in lipofuscin from aged human eyes. Here, human-induced pluripotent stem cell (iPSC)-RPE was generated from healthy individuals to reveal proteomic changes associated with A2E-related RPE cell senescence. A novel RPE cell senescence-related protein, high-mobility group box 1 (HMGB1), was identified based on proteomic mass spectrometry measurements on iPSC-RPE with A2E treatment. Furthermore, HMGB1 upregulated Caveolin-1, which also was related RPE cell senescence. To investigate whether changes in HMGB1 and Caveolin-1 expression under A2E exposure contribute to RPE cell senescence, human ARPE-19 cells were stimulated with A2E; expression of HMGB1, Caveolin-1, tight junction proteins and senescent phenotypes were verified. HMGB1 inhibition alleviated A2E induced cell senescence. Migration of RPE cells was evaluated. Notably, A2E less than or equal to 10μM induced both HMGB1 and Caveolin-1 protein upregulation and HMGB1 translocation, while Caveolin-1 expression was downregulated when there was more than 10μM A2E. Our data indicate that A2E-induced upregulation of HMGB1、Caveolin-1 and HMGB1 release may relate to RPE cell senescence and play a role in the pathogenesis of AMD.
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Affiliation(s)
- Shuo Sun
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Bincui Cai
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Yao Li
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA.,Departments of Ophthalmology, Columbia University, New York, NY 10027, USA
| | - Wenqi Su
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Xuzheng Zhao
- Tangshan Eye Hospital, Tangshan, People's Republic of China
| | - Boteng Gong
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Zhiqing Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Xiaomin Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Yalin Wu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen City, People's Republic of China
| | - Chao Chen
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen City, People's Republic of China
| | - Stephen H Tsang
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA.,Departments of Ophthalmology, Columbia University, New York, NY 10027, USA
| | - Jin Yang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Xiaorong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
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Hammer M, Schultz R, Hasan S, Sauer L, Klemm M, Kreilkamp L, Zweifel L, Augsten R, Meller D. Fundus Autofluorescence Lifetimes and Spectral Features of Soft Drusen and Hyperpigmentation in Age-Related Macular Degeneration. Transl Vis Sci Technol 2020; 9:20. [PMID: 32821492 PMCID: PMC7401897 DOI: 10.1167/tvst.9.5.20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 02/06/2020] [Indexed: 01/13/2023] Open
Abstract
Purpose To investigate the autofluorescence lifetimes as well as spectral characteristics of soft drusen and retinal hyperpigmentation in age-related macular degeneration (AMD). Methods Forty-three eyes with nonexudative AMD were included in this study. Fluorescence lifetime imaging ophthalmoscopy (FLIO), which detects autofluorescence decay over time in the short (SSC) and long (LSC) wavelength channel, was performed. The mean autofluorescence lifetime (τm) and the spectral ratio (sr) of autofluorescence emission in the SSC and LSC were recorded and analyzed. In total, 2760 soft drusen and 265 hyperpigmented areas were identified from color fundus photographs and spectral domain optical coherence tomography (SD-OCT) images and superimposed onto their respective AF images. τm and sr of these lesions were compared with fundus areas without drusen. For clearly hyperfluorescent drusen, the local differences compared to fundus areas without drusen were determined for lifetimes and sr. Results Hyperpigmentation showed significantly longer τm (SSC: 341 ± 81 vs. 289 ± 70 ps, P < 0.001; LSC: 406 ± 42 vs. 343 ± 42 ps, P < 0.001) and higher sr (0.621 ± 0.077 vs. 0.539 ± 0.083, P < 0.001) compared to fundus areas without hyperpigmentation or drusen. No significant difference in τm was found between soft drusen and fundus areas without drusen. However, the sr was significantly higher in soft drusen (0.555 ± 0.077 vs. 0.539 ± 0.081, P < 0.0005). Hyperfluorescent drusen showed longer τm than surrounding fundus areas without drusen (SSC: 18 ± 42 ps, P = 0.074; LSC: 16 ± 29 ps, P = 0.020). Conclusions FLIO can quantitatively characterize the autofluorescence of the fundus, drusen, and hyperpigmentation in AMD. Translational Relevance The experimental FLIO technique was applied in a clinical investigation. As FLIO yields information on molecular changes in AMD, it might support future diagnostics.
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Affiliation(s)
- Martin Hammer
- Department of Ophthalmology, University Hospital Jena, Jena, Germany.,Center for Medical Optics and Photonics, University of Jena, Jena, Germany
| | - Rowena Schultz
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Somar Hasan
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Lydia Sauer
- John A. Moran Eye Center, Salt Lake City, UT, USA
| | - Matthias Klemm
- Technical University Ilmenau, Institute for Biomedical Techniques and Informatics, Ilmenau, Germany
| | - Lukas Kreilkamp
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Lynn Zweifel
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Regine Augsten
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Daniel Meller
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
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36
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Boughton BA, Thomas ORB, Demarais NJ, Trede D, Swearer SE, Grey AC. Detection of small molecule concentration gradients in ocular tissues and humours. JOURNAL OF MASS SPECTROMETRY : JMS 2020; 55:e4460. [PMID: 31654531 DOI: 10.1002/jms.4460] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/02/2019] [Accepted: 10/17/2019] [Indexed: 06/10/2023]
Abstract
The eye is an elegant organ consisting of a number of tissues and fluids with specialised functions that together allow it to effectively transmit and transduce light input to the brain for visual perception. One key determinant of this integrated function is the spatial relationship of ocular tissues. Biomolecular distributions within the main ocular tissues cornea, lens, and retina have been studied extensively in isolation, yet the potential for metabolic communication between ocular tissues via the ocular humours has been difficult to visualise. To address this limitation, the current study presents a method to map spatial distributions of metabolites and small molecules in whole eyes, including ocular humours. Using a tape-transfer system and freeze-drying, the spatial distribution of ocular small molecules was investigated in mouse, rat, fish (black bream), and rabbit eyes using negative ion mode MALDI imaging mass spectrometry. Full-scan imaging was used for discovery experiments, while MS/MS imaging for identification and localisation was also demonstrated. In all eyes, metabolites such as glutathione and phospholipids were localised in the main ocular tissues. In addition, in rodent eyes, major metabolites were distributed relatively uniformly in ocular humours. In contrast, both uniform and spatially defined ocular metabolite distributions were observed in the black bream eye. Tissue and ocular humour distributions were reproducible, as demonstrated by the three-dimensional analysis of a mouse eye, and able to be captured with high spatial resolution analysis. The presented method could be used to further investigate the role of inter-tissue metabolism in ocular health, and to support the development of therapeutics to treat major ocular diseases.
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Affiliation(s)
- Berin A Boughton
- Metabolomics Australia, University of Melbourne, Melbourne, Australia
| | - Oliver R B Thomas
- School of BioSciences, University of Melbourne, Melbourne, Australia
| | - Nicholas J Demarais
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | | | - Stephen E Swearer
- School of BioSciences, University of Melbourne, Melbourne, Australia
| | - Angus C Grey
- School of Medical Sciences, University of Auckland, Auckland, New Zealand
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Augustine J, Troendle EP, Barabas P, McAleese CA, Friedel T, Stitt AW, Curtis TM. The Role of Lipoxidation in the Pathogenesis of Diabetic Retinopathy. Front Endocrinol (Lausanne) 2020; 11:621938. [PMID: 33679605 PMCID: PMC7935543 DOI: 10.3389/fendo.2020.621938] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/21/2020] [Indexed: 12/31/2022] Open
Abstract
Lipids can undergo modification as a result of interaction with reactive oxygen species (ROS). For example, lipid peroxidation results in the production of a wide variety of highly reactive aldehyde species which can drive a range of disease-relevant responses in cells and tissues. Such lipid aldehydes react with nucleophilic groups on macromolecules including phospholipids, nucleic acids, and proteins which, in turn, leads to the formation of reversible or irreversible adducts known as advanced lipoxidation end products (ALEs). In the setting of diabetes, lipid peroxidation and ALE formation has been implicated in the pathogenesis of macro- and microvascular complications. As the most common diabetic complication, retinopathy is one of the leading causes of vision loss and blindness worldwide. Herein, we discuss diabetic retinopathy (DR) as a disease entity and review the current knowledge and experimental data supporting a role for lipid peroxidation and ALE formation in the onset and development of this condition. Potential therapeutic approaches to prevent lipid peroxidation and lipoxidation reactions in the diabetic retina are also considered, including the use of antioxidants, lipid aldehyde scavenging agents and pharmacological and gene therapy approaches for boosting endogenous aldehyde detoxification systems. It is concluded that further research in this area could lead to new strategies to halt the progression of DR before irreversible retinal damage and sight-threatening complications occur.
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Affiliation(s)
- Josy Augustine
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Science, Queen’s University of Belfast, Belfast, United Kingdom
| | - Evan P. Troendle
- Department of Chemistry, King’s College London, London, United Kingdom
| | - Peter Barabas
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Science, Queen’s University of Belfast, Belfast, United Kingdom
| | - Corey A. McAleese
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Science, Queen’s University of Belfast, Belfast, United Kingdom
| | - Thomas Friedel
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Science, Queen’s University of Belfast, Belfast, United Kingdom
| | - Alan W. Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Science, Queen’s University of Belfast, Belfast, United Kingdom
| | - Tim M. Curtis
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Science, Queen’s University of Belfast, Belfast, United Kingdom
- *Correspondence: Tim M. Curtis,
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38
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Age-related macular degeneration: A two-level model hypothesis. Prog Retin Eye Res 2019; 76:100825. [PMID: 31899290 DOI: 10.1016/j.preteyeres.2019.100825] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/19/2019] [Accepted: 12/26/2019] [Indexed: 02/08/2023]
Abstract
Age-related diseases, including age-related macular degeneration (AMD), are of growing importance in a world where population ageing has become a dominant global trend. Although a wide variety of risk factors for AMD have been identified, age itself remains by far the most important risk factor, making it an urgent priority to understand the connections between underlying ageing mechanisms and pathophysiology of AMD. Ageing is both multicausal and variable, so that differences between individuals in biological ageing processes are the focus of a growing number of pathophysiological studies seeking to explain how ageing contributes to chronic, age-related conditions. The aim of this review is to integrate the available knowledge on the pathophysiology of AMD within the framework of the biology of ageing. One highly significant feature of biological ageing is systemic inflammation, which arises as a second-level response to a first level of molecular damage involving oxidative stress, mutations etc. Combining these insights, the various co-existing pathophysiological explanations in AMD arrange themselves according to a two-level hypothesis. Accordingly, we describe how AMD can be considered the consequence of age-related random accumulation of molecular damage at the ocular level and the subsequent systemic inflammatory host response thereof. We summarize evidence and provide original data to enlighten where evidence is lacking. Finally, we discuss how this two-level hypothesis provides a foundation for thoughts and future studies in prevention, prognosis, and intervention.
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Oishi A, Miyata M, Numa S, Otsuka Y, Oishi M, Tsujikawa A. Wide-field fundus autofluorescence imaging in patients with hereditary retinal degeneration: a literature review. Int J Retina Vitreous 2019; 5:23. [PMID: 31890285 PMCID: PMC6907101 DOI: 10.1186/s40942-019-0173-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Background Inherited retinal degeneration (IRD) refers to a heterogenous group of progressive diseases that cause death of photoreceptor cells and subsequent vision loss. These diseases often affect the peripheral retina, objective evaluation of which has been difficult until recently. Fundus autofluorescence (FAF) is a non-invasive retinal imaging technique that depicts the distribution of intrinsic fluorophores in the retina. The primary source of retinal autofluorescence is lipofuscin, which is contained in the retinal pigment epithelium (RPE). Excessive accumulation of lipofuscin and a window defect attributable to loss of photoreceptor pigment result in increased FAF whereas loss of the RPE results in decreased FAF. These changes can be seen during the course of IRD. Mainbody While conventional modalities are limited in their angle of view, recent technologic advances, known as wide-field and ultra-widefield FAF imaging, have enabled visualization of the far peripheral retina. Although clinical application of this technique in patients with IRD is still in its infancy, some studies have already indicated its usefulness. For example, an area with decreased FAF correlates well with a visual field defect in an eye with retinitis pigmentosa (RP) or cone-rod dystrophy. An abnormal FAF pattern may help in the diagnosis of IRD and associated diseases. In addition, female carriers of X-linked RP and female choroideremia show characteristic appearance. Conversely, absence of abnormal FAF despite severe retinal degeneration helps differentiation of cancer-associated retinopathy. Conclusion This paper reviews the principles of FAF, wide-field imaging, and findings in specific diseases. Wide-field imaging, particularly wide-field FAF, will provide further information for the characteristics, prognosis, and pathogenesis of IRD.
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Affiliation(s)
- Akio Oishi
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Shogoin Kawahara-cho 54, Sakyo-ku, Kyoto, Japan
| | - Manabu Miyata
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Shogoin Kawahara-cho 54, Sakyo-ku, Kyoto, Japan
| | - Shogo Numa
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Shogoin Kawahara-cho 54, Sakyo-ku, Kyoto, Japan
| | - Yuki Otsuka
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Shogoin Kawahara-cho 54, Sakyo-ku, Kyoto, Japan
| | - Maho Oishi
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Shogoin Kawahara-cho 54, Sakyo-ku, Kyoto, Japan
| | - Akitaka Tsujikawa
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Shogoin Kawahara-cho 54, Sakyo-ku, Kyoto, Japan
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40
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Gambril JA, Sloan KR, Swain TA, Huisingh C, Zarubina AV, Messinger JD, Ach T, Curcio CA. Quantifying Retinal Pigment Epithelium Dysmorphia and Loss of Histologic Autofluorescence in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2019; 60:2481-2493. [PMID: 31173079 PMCID: PMC6557619 DOI: 10.1167/iovs.19-26949] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Purpose Lipofuscin and melanolipofuscin organelles in retinal pigment epithelium (RPE) cells are signal sources for clinical fundus autofluorescence (AF). To elucidate the subcellular basis of AF imaging, we identified, characterized, and quantified the frequency of RPE morphology and AF phenotypes in donor eyes with age-related macular degeneration (AMD). Methods In 25 RPE-Bruch's membrane flat mounts from 25 eyes, we analyzed 0.4-μm z-stack epifluorescence images of RPE stained with phalloidin for actin cytoskeleton. Using a custom ImageJ plugin, we classified cells selected in a systematic unbiased fashion in six phenotypes representing increasing degrees of pathology. For each cell, area, AF intensity, and number of Voronoi neighbors were compared with phenotype 1 (uniform AF, polygonal morphology) via generalized estimating equations. We also analyzed each cell's neighborhood. Results In 29,323 cells, compared with phenotype 1, all other phenotypes, in order of increasing pathology, had significantly larger area, reduced AF, and more variable number of neighbors. Neighborhood area and AF showed similar, but subtler, trends. Cells with highly autofluorescent granule aggregates are no more autofluorescent than others and are in fact lower overall in AF. Pre-aggregates were found in phenotype 1. Phenotype 2, which exhibited degranulation despite normal cytoskeleton, was the most numerous nonhealthy phenotype (16.23%). Conclusions Despite aggregation of granules that created hyperAF aggregates within cells, overall AF on a per cell basis decreased with increasing severity of dysmorphia (abnormal shape). Data motivate further development of subcellular resolution in clinical fundus AF imaging and inform an ongoing reexamination of the role of lipofuscin in AMD.
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Affiliation(s)
- J Alan Gambril
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Kenneth R Sloan
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Thomas A Swain
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Carrie Huisingh
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Anna V Zarubina
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Jeffrey D Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Thomas Ach
- Department of Ophthalmology, University Hospital Würzburg, Würzburg, Germany
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
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Tao JX, Zhou WC, Zhu XG. Mitochondria as Potential Targets and Initiators of the Blue Light Hazard to the Retina. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:6435364. [PMID: 31531186 PMCID: PMC6721470 DOI: 10.1155/2019/6435364] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/18/2019] [Accepted: 07/25/2019] [Indexed: 12/20/2022]
Abstract
Commercially available white light-emitting diodes (LEDs) have an intense emission in the range of blue light, which has raised a range of public concerns about their potential risks as retinal hazards. Distinct from other visible light components, blue light is characterized by short wavelength, high energy, and strong penetration that can reach the retina with relatively little loss in damage potential. Mitochondria are abundant in retinal tissues, giving them relatively high access to blue light, and chromophores, which are enriched in the retina, have many mitochondria able to absorb blue light and induce photochemical effects. Therefore, excessive exposure of the retina to blue light tends to cause ROS accumulation and oxidative stress, which affect the structure and function of the retinal mitochondria and trigger mitochondria-involved death signaling pathways. In this review, we highlight the essential roles of mitochondria in blue light-induced photochemical damage and programmed cell death in the retina, indicate directions for future research and preventive targets in terms of the blue light hazard to the retina, and suggest applying LED devices in a rational way to prevent the blue light hazard.
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Affiliation(s)
- Jin-Xin Tao
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
- Department of Clinical Medicine, The Second Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Wen-Chuan Zhou
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
- Department of Clinical Medicine, The Second Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Xin-Gen Zhu
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
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42
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Reiter GS, Told R, Baratsits M, Hecht A, Schlanitz FG, Sacu S, Schmidt‐Erfurth U. Repeatability and reliability of quantitative fundus autofluorescence imaging in patients with early and intermediate age-related macular degeneration. Acta Ophthalmol 2019; 97:e526-e532. [PMID: 30549203 DOI: 10.1111/aos.13987] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 11/09/2018] [Indexed: 12/11/2022]
Abstract
PURPOSE Quantification of fundus autofluorescence has only recently become available. We report our findings on the evaluation of the repeatability and reliability of quantitative fundus autofluorescence (qAF) measurements in patients with early and intermediate age-related macular degeneration (AMD), using the first approved and commercially available instrument. METHODS A total of 43 eyes of 22 patients (aged between 52 and 84 years) diagnosed with early and intermediate AMD were included. All eyes were imaged at day 1, 3 months and 6 months using a modified scanning laser ophthalmoscope, equipped with an internal fluorescent reference. Mean qAF values were calculated for the fovea and for each concentric ring of the Delori pattern. Repeatability and reliability were calculated using Bland-Altman analysis and intraclass correlation (ICC). RESULTS The mean patient age was 73.5 ± 7.9 years. Sixteen patients (73%) were female. qAF repeatability of the eight segments in the middle ring of the Delori pattern (qAFM 8 ) for between sessions was ±8.2%. Agreement at 3- and 6-month follow-up in eyes without retinal changes was ±8.3% and ±9.8%, respectively. Reliability of qAFM 8 was high for all images acquired [ICC = 0.98 (CI: 0.96-0.99), 0.97 (0.93-0.99) and 0.98 (0.92-0.99)]. Agreement at 3- and 6-month follow-up in eyes with retinal changes was ±18.1% and ±20.2%, respectively. Intraclass correlation (ICC) was slightly lower in eyes with retinal changes at 0.93 (0.84-0.97) and 0.96 (0.91-0.98), respectively. CONCLUSIONS Quantitative autofluorescence shows excellent repeatability and reliability as well as follow-up agreement in patients with early and intermediate AMD without retinal changes. This is relevant when conducting longitudinal studies using qAF.
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Affiliation(s)
- Gregor Sebastian Reiter
- Department of Ophthalmology and Optometry Vienna Trial Center (VTC) Medical University of Vienna Vienna Austria
| | - Reinhard Told
- Department of Ophthalmology and Optometry Vienna Trial Center (VTC) Medical University of Vienna Vienna Austria
| | - Magdalena Baratsits
- Department of Ophthalmology and Optometry Vienna Trial Center (VTC) Medical University of Vienna Vienna Austria
| | - Alexander Hecht
- Department of Ophthalmology and Optometry Vienna Trial Center (VTC) Medical University of Vienna Vienna Austria
| | - Ferdinand Georg Schlanitz
- Department of Ophthalmology and Optometry Vienna Trial Center (VTC) Medical University of Vienna Vienna Austria
| | - Stefan Sacu
- Department of Ophthalmology and Optometry Vienna Trial Center (VTC) Medical University of Vienna Vienna Austria
| | - Ursula Schmidt‐Erfurth
- Department of Ophthalmology and Optometry Vienna Trial Center (VTC) Medical University of Vienna Vienna Austria
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Lin CH, Wu MR, Huang WJ, Chow DSL, Hsiao G, Cheng YW. Low-Luminance Blue Light-Enhanced Phototoxicity in A2E-Laden RPE Cell Cultures and Rats. Int J Mol Sci 2019; 20:ijms20071799. [PMID: 30979028 PMCID: PMC6480556 DOI: 10.3390/ijms20071799] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/30/2019] [Accepted: 04/08/2019] [Indexed: 12/28/2022] Open
Abstract
N-retinylidene-N-retinylethanolamine (A2E) and other bisretinoids are components of lipofuscin and accumulate in retinal pigment epithelial (RPE) cells—these adducts are recognized in the pathogenesis of retinal degeneration. Further, blue light-emitting diode (LED) light (BLL)-induced retinal toxicity plays an important role in retinal degeneration. Here, we demonstrate that low-luminance BLL enhances phototoxicity in A2E-laden RPE cells and rats. RPE cells were subjected to synthetic A2E, and the effects of BLL on activation of apoptotic biomarkers were examined by measuring the levels of cleaved caspase-3. BLL modulates the protein expression of zonula-occludens 1 (ZO-1) and paracellular permeability in A2E-laden RPE cells. Early inflammatory and angiogenic genes were also screened after short-term BLL exposure. In this study, we developed a rat model for A2E treatment with or without BLL exposure for 21 days. BLL exposure caused fundus damage, decreased total retinal thickness, and caused neuron transduction injury in the retina, which were consistent with the in vitro data. We suggest that the synergistic effects of BLL and A2E accumulation in the retina increase the risk of retinal degeneration. These outcomes help elucidate the associations between BLL/A2E and angiogenic/apoptotic mechanisms, as well as furthering therapeutic strategies.
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Affiliation(s)
- Cheng-Hui Lin
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 11031, Taiwan.
| | - Man-Ru Wu
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 11031, Taiwan.
| | - Wei-Jan Huang
- Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei 11031, Taiwan.
| | - Diana Shu-Lian Chow
- Institute of Drug Education and Research, College of Pharmacy, University of Houston, Texas 77004, USA.
| | - George Hsiao
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
| | - Yu-Wen Cheng
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 11031, Taiwan.
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Shah M, Cabrera-Ghayouri S, Christie LA, Held KS, Viswanath V. Translational Preclinical Pharmacologic Disease Models for Ophthalmic Drug Development. Pharm Res 2019; 36:58. [PMID: 30805711 PMCID: PMC6394514 DOI: 10.1007/s11095-019-2588-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 02/08/2019] [Indexed: 12/14/2022]
Abstract
Preclinical models of human diseases are critical to our understanding of disease etiology, pathology, and progression and enable the development of effective treatments. An ideal model of human disease should capture anatomical features and pathophysiological mechanisms, mimic the progression pattern, and should be amenable to evaluating translational endpoints and treatment approaches. Preclinical animal models have been developed for a variety of human ophthalmological diseases to mirror disease mechanisms, location of the affected region in the eye and severity. These models offer clues to aid in our fundamental understanding of disease pathogenesis and enable progression of new therapies to clinical development by providing an opportunity to gain proof of concept (POC). Here, we review preclinical animal models associated with development of new therapies for diseases of the ocular surface, glaucoma, presbyopia, and retinal diseases, including diabetic retinopathy and age-related macular degeneration (AMD). We have focused on summarizing the models critical to new drug development and described the translational features of the models that contributed to our understanding of disease pathogenesis and establishment of preclinical POC.
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Affiliation(s)
- Mihir Shah
- Biological Research, Allergan plc, 2525 Dupont Drive, Irvine, California, 92612, USA
| | - Sara Cabrera-Ghayouri
- Biological Research, Allergan plc, 2525 Dupont Drive, Irvine, California, 92612, USA
| | - Lori-Ann Christie
- Biological Research, Allergan plc, 2525 Dupont Drive, Irvine, California, 92612, USA
| | - Katherine S Held
- Biological Research, Allergan plc, 2525 Dupont Drive, Irvine, California, 92612, USA
| | - Veena Viswanath
- Biological Research, Allergan plc, 2525 Dupont Drive, Irvine, California, 92612, USA.
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Leclaire MD, Nettels-Hackert G, König J, Höhn A, Grune T, Uhlig CE, Hansen U, Eter N, Heiduschka P. Lipofuscin-dependent stimulation of microglial cells. Graefes Arch Clin Exp Ophthalmol 2019; 257:931-952. [PMID: 30693383 DOI: 10.1007/s00417-019-04253-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 01/10/2019] [Accepted: 01/17/2019] [Indexed: 01/10/2023] Open
Abstract
PURPOSE To examine the reaction of microglial cells (MG) when incubated with lipofuscin (LP) in vitro with emphasis on the immunological reaction of the MG toward LP and the suppression of this reaction by immunomodulatory agents. MG are involved in the pathogenesis of degenerative eye disorders such as age-related macular degeneration (AMD). LP is a heterogeneous waste material that accumulates in the retinal pigment epithelium (RPE) cells with advancing age. LP is known to have toxic effects on RPE cells and therefore an elevated LP-derived fundus autofluorescence is a risk factor for AMD development. MG in the subretinal space have been reported in eyes affected by AMD. Moreover, in senescent mice, subretinal MG were found, which display an autofluorescence that may be derived from LP uptake. METHODS In this study, we incubated MG (BV-2 cell line and primary cells from murine brain) in vitro with LP isolated from the human RPE. We observed phagocytosis, studied cell morphologies, and analyzed the cell culture supernatants. We also investigated the effect of the immunomodulatory agents hydrocortisone (HC), minocycline, and the tripeptide TKP. RESULTS The MG phagocytosed the LP quickly and completely. We detected highly elevated levels of pro-inflammatory cytokines (especially of IL-6, IL-23p19, TNF-α, KC, RANTES, and IL-1α) in the cell culture supernatants. Furthermore, levels of vascular endothelial growth factor (VEGF) were raised in BV-2 cells. Anti-inflammatory agents added to the cell cultures inhibited the inflammatory reaction, in particular hydrocortisone (HC). Minocycline and TKP had less impact on the cytokine release. CONCLUSION The interaction of MG and LP could play a role in the development of retinal degeneration by triggering an inflammatory reaction and angiogenesis.
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Affiliation(s)
- Martin Dominik Leclaire
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Gerburg Nettels-Hackert
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Jeannette König
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Annika Höhn
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Tilman Grune
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Constantin E Uhlig
- Cornea Bank Münster, Department of Ophthalmology, University Medical Center, Münster, Germany
| | - Uwe Hansen
- Institute of Experimental Musculoskeletal Medicine, Medical Faculty, University of Münster, Münster, Germany
| | - Nicole Eter
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Peter Heiduschka
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany.
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Curcio CA. Soft Drusen in Age-Related Macular Degeneration: Biology and Targeting Via the Oil Spill Strategies. Invest Ophthalmol Vis Sci 2018; 59:AMD160-AMD181. [PMID: 30357336 PMCID: PMC6733535 DOI: 10.1167/iovs.18-24882] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AMD is a major cause of legal blindness in older adults approachable through multidisciplinary research involving human tissues and patients. AMD is a vascular-metabolic-inflammatory disease, in which two sets of extracellular deposits, soft drusen/basal linear deposit (BLinD) and subretinal drusenoid deposit (SDD), confer risk for end-stages of atrophy and neovascularization. Understanding how deposits form can lead to insights for new preventions and therapy. The topographic correspondence of BLinD and SDD with cones and rods, respectively, suggest newly realized exchange pathways among outer retinal cells and across Bruch's membrane and the subretinal space, in service of highly evolved, eye-specific physiology. This review focuses on soft drusen/BLinD, summarizing evidence that a major ultrastructural component is large apolipoprotein B,E-containing, cholesterol-rich lipoproteins secreted by the retinal pigment epithelium (RPE) that offload unneeded lipids of dietary and outer segment origin to create an atherosclerosis-like progression in the subRPE-basal lamina space. Clinical observations and an RPE cell culture system combine to suggest that soft drusen/BLinD form when secretions of functional RPE back up in the subRPE-basal lamina space by impaired egress across aged Bruch's membrane-choriocapillary endothelium. The soft drusen lifecycle includes growth, anterior migration of RPE atop drusen, then collapse, and atrophy. Proof-of-concept studies in humans and animal models suggest that targeting the “Oil Spill in Bruch's membrane” offers promise of treating a process in early AMD that underlies progression to both end-stages. A companion article addresses the antecedents of soft drusen within the biology of the macula.
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Affiliation(s)
- Christine A Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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Curcio CA. Antecedents of Soft Drusen, the Specific Deposits of Age-Related Macular Degeneration, in the Biology of Human Macula. Invest Ophthalmol Vis Sci 2018; 59:AMD182-AMD194. [PMID: 30357337 PMCID: PMC6733529 DOI: 10.1167/iovs.18-24883] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AMD pathobiology was irreversibly changed by the recent discovery of extracellular cholesterol-containing deposits in the subretinal space, between the photoreceptors and retinal pigment epithelium (RPE), called subretinal drusenoid deposits (SDDs). SDDs strikingly mirror the topography of rod photoreceptors in human macula, raising the question of whether an equivalent process results in a deposition related to foveal cones. Herein we propose that AMD's pathognomonic lesion-soft drusen and basal linear deposit (BLinD, same material, diffusely distributed)-is the leading candidate. Epidemiologic, clinical, and histologic data suggest that these deposits are most abundant in the central macula, under the fovea. Strong evidence presented in a companion article supports the idea that the dominant ultrastructural component is large apolipoprotein B,E-containing lipoproteins, constitutively secreted by RPE. Lipoprotein fatty acids are dominated by linoleate (implicating diet) rather than docosahexaenoate (implicating photoreceptors); we seek within the retina cellular relationships and dietary drivers to explain soft druse topography. The delivery of xanthophyll pigments to highly evolved and numerous Müller cells in the human fovea, through RPE, is one strong candidate, because Müller cells are the main reservoir of these pigments, which replenish from diet. We propose that the evolution of neuroglial relations and xanthophyll delivery that underlie exquisite human foveal vision came with a price, that is, soft drusen and sequela, long after our reproductive years.
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Affiliation(s)
- Christine A Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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The clinical relevance of visualising the peripheral retina. Prog Retin Eye Res 2018; 68:83-109. [PMID: 30316018 DOI: 10.1016/j.preteyeres.2018.10.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 10/01/2018] [Accepted: 10/07/2018] [Indexed: 01/04/2023]
Abstract
Recent developments in imaging technologies now allow the documentation, qualitative and quantitative evaluation of peripheral retinal lesions. As wide field retinal imaging, capturing both the central and peripheral retina up to 200° eccentricity, is becoming readily available the question is: what is it that we gain by imaging the periphery? Based on accumulating evidence it is clear that findings in the periphery do not always associate to those observed in the posterior pole. However, the newly acquired information may provide useful clues to previously unrecognised disease features and may facilitate more accurate disease prognostication. In this review, we explore the anatomy and physiology of the peripheral retina, focusing on how it differs from the posterior pole, recount the history of peripheral retinal imaging, describe various peripheral retinal lesions and evaluate the overall relevance of peripheral retinal findings to different diseases.
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Light-induced generation and toxicity of docosahexaenoate-derived oxidation products in retinal pigmented epithelial cells. Exp Eye Res 2018; 181:325-345. [PMID: 30296412 DOI: 10.1016/j.exer.2018.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 09/21/2018] [Accepted: 09/23/2018] [Indexed: 12/11/2022]
Abstract
Oxidative cleavage of docosahexaenoate (DHA) in retinal pigmented epithelial (RPE) cells produces 4-hydroxy-7-oxohept-5-enoic acid (HOHA) esters of 2-lysophosphatidylcholine (PC). HOHA-PC spontaneously releases a membrane-permeant HOHA lactone that modifies primary amino groups of proteins and ethanolamine phospholipids to produce 2-(ω-carboxyethyl)pyrrole (CEP) derivatives. CEPs have significant pathological relevance to age-related macular degeneration (AMD) including activation of CEP-specific T-cells leading to inflammatory M1 polarization of macrophages in the retina involved in "dry AMD" and TLR2-dependent induction of angiogenesis that characterizes "wet AMD". RPE cells accumulate DHA from shed rod photoreceptor outer segments through phagocytosis and from plasma lipoproteins secreted by the liver through active uptake from the choriocapillaris. As a cell model of light-induced oxidative damage of DHA phospholipids in RPE cells, ARPE-19 cells were supplemented with DHA, with or without the lipofuscin fluorophore A2E. In this model, light exposure, in the absence of A2E, promoted the generation HOHA lactone-glutathione (GSH) adducts, depletion of intracellular GSH and a competing generation of CEPs. While DHA-rich RPE cells exhibit an inherent proclivity toward light-induced oxidative damage, photosensitization by A2E nearly doubled the amount of lipid oxidation and expanded the spectral range of photosensitivity to longer wavelengths. Exposure of ARPE-19 cells to 1 μM HOHA lactone for 24 h induced massive (50%) loss of lysosomal membrane integrity and caused loss of mitochondrial membrane potential. Using senescence-associated β-galactosidase (SA β-gal) staining that detects lysosomal β-galactosidase, we determined that exposure to HOHA lactone induces senescence in ARPE-19 cells. The present study shows that products of light-induced oxidative damage of DHA phospholipids in the absence of A2E can lead to RPE cell dysfunction. Therefore, their toxicity may be especially important in the early stages of AMD before RPE cells accumulate lipofuscin fluorophores.
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Sauer L, Andersen KM, Dysli C, Zinkernagel MS, Bernstein PS, Hammer M. Review of clinical approaches in fluorescence lifetime imaging ophthalmoscopy. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-20. [PMID: 30182580 PMCID: PMC8357196 DOI: 10.1117/1.jbo.23.9.091415] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 07/24/2018] [Indexed: 05/04/2023]
Abstract
Autofluorescence-based imaging techniques have become very important in the ophthalmological field. Being noninvasive and very sensitive, they are broadly used in clinical routines. Conventional autofluorescence intensity imaging is largely influenced by the strong fluorescence of lipofuscin, a fluorophore that can be found at the level of the retinal pigment epithelium. However, different endogenous retinal fluorophores can be altered in various diseases. Fluorescence lifetime imaging ophthalmoscopy (FLIO) is an imaging modality to investigate the autofluorescence of the human fundus in vivo. It expands the level of information, as an addition to investigating the fluorescence intensity, and autofluorescence lifetimes are captured. The Heidelberg Engineering Spectralis-based fluorescence lifetime imaging ophthalmoscope is used to investigate a 30-deg retinal field centered at the fovea. It detects FAF decays in short [498 to 560 nm, short spectral channel (SSC) and long (560 to 720 nm, long spectral channel (LSC)] spectral channels, the mean fluorescence lifetimes (τm) are calculated using bi- or triexponential approaches. These are meant to be relatively independent of the fluorophore's intensity; therefore, fluorophores with less intense fluorescence can be detected. As an example, FLIO detects the fluorescence of macular pigment, retinal carotenoids that help protect the human fundus from light damages. Furthermore, FLIO is able to detect changes related to various retinal diseases, such as age-related macular degeneration, albinism, Alzheimer's disease, diabetic retinopathy, macular telangiectasia type 2, retinitis pigmentosa, and Stargardt disease. Some of these changes can already be found in healthy eyes and may indicate a risk to developing such diseases. Other changes in already affected eyes seem to indicate disease progression. This review article focuses on providing detailed information on the clinical findings of FLIO. This technique detects not only structural changes at very early stages but also metabolic and disease-related alterations. Therefore, it is a very promising tool that might soon be used for early diagnostics.
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Affiliation(s)
- Lydia Sauer
- University Hospital Jena, Jena, Thuringia, Germany
- University of Utah, John A. Moran Eye Center, Salt Lake City, Utah, United States
| | - Karl M. Andersen
- University of Utah, John A. Moran Eye Center, Salt Lake City, Utah, United States
- Geisinger Commonwealth School of Medicine, Scranton, Pennsylvania, United States
| | - Chantal Dysli
- Bern University Hospital, Inselspital, Department of Ophthalmology, Bern, Switzerland
| | - Martin S. Zinkernagel
- Bern University Hospital, Inselspital, Department of Ophthalmology, Bern, Switzerland
| | - Paul S. Bernstein
- University of Utah, John A. Moran Eye Center, Salt Lake City, Utah, United States
| | - Martin Hammer
- University Hospital Jena, Jena, Thuringia, Germany
- University of Jena, Center for Biomedical Optics and Photonics, Jena, Germany
- Address all correspondence to: Martin Hammer, E-mail:
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