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Chucair-Elliott AJ, Ocañas SR, Pham K, Machalinski A, Plafker S, Stout MB, Elliott MH, Freeman WM. Age- and sex- divergent translatomic responses of the mouse retinal pigmented epithelium. Neurobiol Aging 2024; 140:41-59. [PMID: 38723422 PMCID: PMC11173338 DOI: 10.1016/j.neurobiolaging.2024.04.012] [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: 10/24/2023] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/18/2024]
Abstract
Aging is the main risk factor for age-related macular degeneration (AMD), a retinal neurodegenerative disease that leads to irreversible blindness, particularly in people over 60 years old. Retinal pigmented epithelium (RPE) atrophy is an AMD hallmark. Genome-wide chromatin accessibility, DNA methylation, and gene expression studies of AMD and control RPE demonstrate epigenomic/transcriptomic changes occur during AMD onset and progression. However, mechanisms by which molecular alterations of normal aging impair RPE function and contribute to AMD pathogenesis are unclear. Here, we specifically interrogate the RPE translatome with advanced age and across sexes in a novel RPE reporter mouse model. We find differential age- and sex- associated transcript expression with overrepresentation of pathways related to inflammation in the RPE. Concordant with impaired RPE function, the phenotypic changes in the aged translatome suggest that aged RPE becomes immunologically active, in both males and females, with some sex-specific signatures, which supports the need for sex representation for in vivo studies.
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Affiliation(s)
- Ana J Chucair-Elliott
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.
| | - Sarah R Ocañas
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Kevin Pham
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Adeline Machalinski
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Scott Plafker
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Michael B Stout
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Michael H Elliott
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Willard M Freeman
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA.
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2
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Rao NT, Sumaroka A, Santos AJ, Parchinski KM, Weber ML, Maguire AM, Cideciyan AV, Aleman TS. Detailed phenotype and long-term follow-up of RAB28-associated cone-rod dystrophy. Ophthalmic Genet 2024:1-10. [PMID: 38956823 DOI: 10.1080/13816810.2024.2362204] [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: 02/14/2024] [Accepted: 05/27/2024] [Indexed: 07/04/2024]
Abstract
PURPOSE To gain an insight into the pathophysiology of RAB28-associated inherited retinal degeneration through detailed phenotyping and long-term longitudinal follow-up. METHODS The patient underwent complete ophthalmic examinations. Visual function was assessed with microperimetry, full-field electroretinography (ffERG), imaging with optical coherence tomography (OCT), short-wave (SW), and near-infrared (NIR) fundus autofluorescence (FAF). RESULTS A healthy Haitian woman with homozygous pathogenic variants (c.68C > T; p.Ser23Phe) in RAB28 presented at 16 years of age with a four-year history of blurred vision. Visual acuities were 20/125 in each eye, which remained relatively stable since. At age 27, cone ffERGs were non-detectable and borderline for rod-mediated responses. Kinetic fields were full to a V-4e target, undetectable to a small I-4e stimulus. Microperimetry showed an absolute central scotoma surrounded by a pericentral relative scotoma. SD-OCT showed an undetectable or barely detectable foveal and parafoveal photoreceptor outer nuclear layer (ONL), photoreceptor outer segment (POS), and retinal pigment epithelium (RPE) signals and loss of the SW- and NIR-FAF signals. This atrophic region was separated from a normally laminated retina by a narrow transition zone (TZ) of hyper SW- and NIR-FAF that co-localized with preserved ONL but abnormally thinned POS and RPE. There was minimal centrifugal (<100 μ m) expansion over a six-year period. CONCLUSION The cone-rod dystrophy phenotype documented herein supports a critical role of RAB28 for cone function and POS maintenance. Severe central photoreceptor and RPE loss with a predilection for POS loss in TZs suggests possible disruptions of complex mechanisms that maintain central cone photoreceptor and RPE homeostasis.
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Affiliation(s)
- Nitya T Rao
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Alexander Sumaroka
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Arlene J Santos
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kelsey M Parchinski
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mariejel L Weber
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Albert M Maguire
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Tomas S Aleman
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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3
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Zhang Z, Liang F, Chang J, Shan X, Yin Z, Wang L, Li S. Autophagy in dry AMD: A promising therapeutic strategy for retinal pigment epithelial cell damage. Exp Eye Res 2024; 242:109889. [PMID: 38593971 DOI: 10.1016/j.exer.2024.109889] [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: 11/24/2023] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 04/11/2024]
Abstract
Dry age-related macular degeneration (AMD) is a prevalent clinical condition that leads to permanent damage to central vision and poses a significant threat to patients' visual health. Although the pathogenesis of dry AMD remains unclear, there is consensus on the role of retinal pigment epithelium (RPE) damage. Oxidative stress and chronic inflammation are major contributors to RPE cell damage, and the NOD-like receptor thermoprotein structural domain-associated protein 3 (NLRP3) inflammasome mediates the inflammatory response leading to apoptosis in RPE cells. Furthermore, lipofuscin accumulation results in oxidative stress, NLRP3 activation, and the development of vitelliform lesions, a hallmark of dry AMD, all of which may contribute to RPE dysfunction. The process of autophagy, involving the encapsulation, recognition, and transport of accumulated proteins and dead cells to the lysosome for degradation, is recognized as a significant pathway for cellular self-protection and homeostasis maintenance. Recently, RPE cell autophagy has been discovered to be closely linked to the development of macular degeneration, positioning autophagy as a cutting-edge research area in the realm of dry AMD. In this review, we present an overview of how lipofuscin, oxidative stress, and the NLRP3 inflammasome damage the RPE through their respective causal mechanisms. We summarized the connection between autophagy, oxidative stress, and NLRP3 inflammatory cytokines. Our findings suggest that targeting autophagy improves RPE function and sustains visual health, offering new perspectives for understanding the pathogenesis and clinical management of dry AMD.
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Affiliation(s)
- Zhao Zhang
- Tianjin University of Chinese Medicine, Tianjin, 300193, China; The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Fengming Liang
- The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China.
| | - Jun Chang
- Tianjin University of Chinese Medicine, Tianjin, 300193, China; The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Xiaoqian Shan
- Tianjin University of Chinese Medicine, Tianjin, 300193, China; The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Zhixian Yin
- Hebei University of Technology, School of Electronics and Information Engineering, Tianjin, 300401, China
| | - Li Wang
- The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Shujiao Li
- Eye Hospital, China Academy of Chinese Medical Sciences, Beijing, 100040, China
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Gofas-Salas E, Lee DMW, Rondeau C, Grieve K, Rossi EA, Paques M, Gocho K. Comparison between Two Adaptive Optics Methods for Imaging of Individual Retinal Pigmented Epithelial Cells. Diagnostics (Basel) 2024; 14:768. [PMID: 38611681 PMCID: PMC11012195 DOI: 10.3390/diagnostics14070768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
The Retinal Pigment Epithelium (RPE) plays a prominent role in diseases such as age-related macular degeneration, but imaging individual RPE cells is challenging due to their high absorption and low autofluorescence emission. The RPE lies beneath the highly reflective photoreceptor layer (PR) and contains absorptive pigments, preventing direct backscattered light detection when the PR layer is intact. Here, we used near-infrared autofluorescence adaptive optics scanning laser ophthalmoscopy (NIRAF AOSLO) and transscleral flood imaging (TFI) in the same healthy eyes to cross-validate these approaches. Both methods revealed a consistent RPE mosaic pattern and appeared to reflect a distribution of fluorophores consistent with findings from histological studies. Interestingly, even in apparently healthy RPE, we observed dynamic changes over months, suggesting ongoing cellular activity or alterations in fluorophore distribution. These findings emphasize the value of NIRAF AOSLO and TFI in understanding RPE morphology and dynamics.
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Affiliation(s)
- Elena Gofas-Salas
- Department of Photonics, Institut de la Vision, INSERM, CNRS, Sorbonne Université, 17 rue Moreau, F-75012 Paris, France;
- CIC 1423, CHNO des Quinze-Vingts, INSERM-DGOS 28 rue de Charenton, F-75012 Paris, France; (M.P.); (K.G.)
| | - Daniel M. W. Lee
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA; (D.M.W.L.); (E.A.R.)
| | | | - Kate Grieve
- Department of Photonics, Institut de la Vision, INSERM, CNRS, Sorbonne Université, 17 rue Moreau, F-75012 Paris, France;
- CIC 1423, CHNO des Quinze-Vingts, INSERM-DGOS 28 rue de Charenton, F-75012 Paris, France; (M.P.); (K.G.)
| | - Ethan A. Rossi
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA; (D.M.W.L.); (E.A.R.)
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Michel Paques
- CIC 1423, CHNO des Quinze-Vingts, INSERM-DGOS 28 rue de Charenton, F-75012 Paris, France; (M.P.); (K.G.)
| | - Kiyoko Gocho
- CIC 1423, CHNO des Quinze-Vingts, INSERM-DGOS 28 rue de Charenton, F-75012 Paris, France; (M.P.); (K.G.)
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5
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Iliescu DA, Ghita AC, Ilie LA, Voiculescu SE, Geamanu A, Ghita AM. Non-Neovascular Age-Related Macular Degeneration Assessment: Focus on Optical Coherence Tomography Biomarkers. Diagnostics (Basel) 2024; 14:764. [PMID: 38611677 PMCID: PMC11011935 DOI: 10.3390/diagnostics14070764] [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: 02/28/2024] [Revised: 03/27/2024] [Accepted: 03/31/2024] [Indexed: 04/14/2024] Open
Abstract
The imagistic evaluation of non-neovascular age-related macular degeneration (AMD) is crucial for diagnosis, monitoring progression, and guiding management of the disease. Dry AMD, characterized primarily by the presence of drusen and retinal pigment epithelium atrophy, requires detailed visualization of the retinal structure to assess its severity and progression. Several imaging modalities are pivotal in the evaluation of non-neovascular AMD, including optical coherence tomography, fundus autofluorescence, or color fundus photography. In the context of emerging therapies for geographic atrophy, like pegcetacoplan, it is critical to establish the baseline status of the disease, monitor the development and expansion of geographic atrophy, and to evaluate the retina's response to potential treatments in clinical trials. The present review, while initially providing a comprehensive description of the pathophysiology involved in AMD, aims to offer an overview of the imaging modalities employed in the evaluation of non-neovascular AMD. Special emphasis is placed on the assessment of progression biomarkers as discerned through optical coherence tomography. As the landscape of AMD treatment continues to evolve, advanced imaging techniques will remain at the forefront, enabling clinicians to offer the most effective and tailored treatments to their patients.
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Affiliation(s)
- Daniela Adriana Iliescu
- Department of Physiology, “Carol Davila” University of Medicine and Pharmacy, 8 Eroii Sanitari Bld., 050474 Bucharest, Romania; (S.E.V.); (A.M.G.)
- Ocularcare Ophthalmology Clinic, 128 Ion Mihalache Bld., 012244 Bucharest, Romania; (A.C.G.); (L.A.I.)
| | - Ana Cristina Ghita
- Ocularcare Ophthalmology Clinic, 128 Ion Mihalache Bld., 012244 Bucharest, Romania; (A.C.G.); (L.A.I.)
| | - Larisa Adriana Ilie
- Ocularcare Ophthalmology Clinic, 128 Ion Mihalache Bld., 012244 Bucharest, Romania; (A.C.G.); (L.A.I.)
| | - Suzana Elena Voiculescu
- Department of Physiology, “Carol Davila” University of Medicine and Pharmacy, 8 Eroii Sanitari Bld., 050474 Bucharest, Romania; (S.E.V.); (A.M.G.)
| | - Aida Geamanu
- Ophthalmology Department, Bucharest University Emergency Hospital, 169 Independence Street, 050098 Bucharest, Romania;
| | - Aurelian Mihai Ghita
- Department of Physiology, “Carol Davila” University of Medicine and Pharmacy, 8 Eroii Sanitari Bld., 050474 Bucharest, Romania; (S.E.V.); (A.M.G.)
- Ocularcare Ophthalmology Clinic, 128 Ion Mihalache Bld., 012244 Bucharest, Romania; (A.C.G.); (L.A.I.)
- Ophthalmology Department, Bucharest University Emergency Hospital, 169 Independence Street, 050098 Bucharest, Romania;
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6
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Dontsov A, Ostrovsky M. Retinal Pigment Epithelium Pigment Granules: Norms, Age Relations and Pathology. Int J Mol Sci 2024; 25:3609. [PMID: 38612421 PMCID: PMC11011557 DOI: 10.3390/ijms25073609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/14/2024] Open
Abstract
The retinal pigment epithelium (RPE), which ensures the normal functioning of the neural retina, is a pigmented single-cell layer that separates the retina from the Bruch's membrane and the choroid. There are three main types of pigment granules in the RPE cells of the human eye: lipofuscin granules (LG) containing the fluorescent "age pigment" lipofuscin, melanoprotein granules (melanosomes, melanolysosomes) containing the screening pigment melanin and complex melanolipofuscin granules (MLG) containing both types of pigments simultaneously-melanin and lipofuscin. This review examines the functional role of pigment granules in the aging process and in the development of oxidative stress and associated pathologies in RPE cells. The focus is on the process of light-induced oxidative degradation of pigment granules caused by reactive oxygen species. The reasons leading to increased oxidative stress in RPE cells as a result of the oxidative degradation of pigment granules are considered. A mechanism is proposed to explain the phenomenon of age-related decline in melanin content in RPE cells. The essence of the mechanism is that when the lipofuscin part of the melanolipofuscin granule is exposed to light, reactive oxygen species are formed, which destroy the melanin part. As more melanolipofuscin granules are formed with age and the development of degenerative diseases, the melanin in pigmented epithelial cells ultimately disappears.
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Affiliation(s)
| | - Mikhail Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia;
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7
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Bourauel L, Vaisband M, von der Emde L, Bermond K, Tarau IS, Heintzmann R, Holz FG, Curcio CA, Hasenauer J, Ach T. Spectral Analysis of Human Retinal Pigment Epithelium Cells in Healthy and AMD Eyes. Invest Ophthalmol Vis Sci 2024; 65:10. [PMID: 38170540 PMCID: PMC10768704 DOI: 10.1167/iovs.65.1.10] [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: 05/26/2023] [Accepted: 12/08/2023] [Indexed: 01/05/2024] Open
Abstract
Purpose Retinal pigment epithelium (RPE) cells show strong autofluorescence (AF). Here, we characterize the AF spectra of individual RPE cells in healthy eyes and those affected by age-related macular degeneration (AMD) and investigate associations between AF spectral response and the number of intracellular AF granules per cell. Methods RPE-Bruch's membrane flatmounts of 22 human donor eyes, including seven AMD-affected eyes (early AMD, three; geographic atrophy, one; neovascular, three) and 15 unaffected macula (<51 years, eight; >80 years, seven), were imaged at the fovea, perifovea, and near-periphery using confocal AF microscopy (excitation 488 nm), and emission spectra were recorded (500-710 nm). RPE cells were manually segmented with computer assistance and stratified by disease status, and emission spectra were analyzed using cubic spline transforms. Intracellular granules were manually counted and classified. Linear mixed models were used to investigate associations between spectra and the number of intracellular granules. Results Spectra of 5549 RPE cells were recorded. The spectra of RPE cells in healthy eyes showed similar emission curves that peaked at 580 nm for fovea and perifovea and at 575 and 580 nm for near-periphery. RPE spectral curves in AMD eyes differed significantly, being blue shifted by 10 nm toward shorter wavelengths. No significant association coefficients were found between wavelengths and granule counts. Conclusions This large series of RPE cell emission spectra at precisely predefined retinal locations showed a hypsochromic spectral shift in AMD. Combining different microscopy techniques, our work has identified cellular RPE spectral AF and subcellular granule properties that will inform future in vivo investigations using single-cell imaging.
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Affiliation(s)
- Leonie Bourauel
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Marc Vaisband
- Institute of Life & Medical Sciences, University of Bonn, Bonn, Germany
- Department of Internal Medicine III with Haematology, Medical Oncology, Haemostaseology, Infectiology and Rheumatology, Oncologic Center, Salzburg Cancer Research Institute Laboratory for Immunological and Molecular Cancer Research, Paracelsus Medical University, Salzburg, Austria
- Cancer Cluster Salzburg, Salzburg, Austria
| | | | - Katharina Bermond
- Department of Ophthalmology, Ludwigshafen Hospital, Ludwigshafen, Germany
| | - Ioana Sandra Tarau
- Department of Ophthalmology, Asklepios Klinik Nord - Heidberg, Hamburg, Germany
| | - Rainer Heintzmann
- Leibniz Institute of Photonic Technology, Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Jena, Germany
| | - Frank G. Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Christine A. Curcio
- Department of Ophthalmology, University of Alabama at Birmingham, Alabama, Alabama, United States
| | - Jan Hasenauer
- Institute of Life & Medical Sciences, University of Bonn, Bonn, Germany
| | - Thomas Ach
- Department of Ophthalmology, University of Bonn, Bonn, Germany
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8
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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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Lindell M, Kar D, Sedova A, Kim YJ, Packer OS, Schmidt-Erfurth U, Sloan KR, Marsh M, Dacey DM, Curcio CA, Pollreisz A. Volumetric Reconstruction of a Human Retinal Pigment Epithelial Cell Reveals Specialized Membranes and Polarized Distribution of Organelles. Invest Ophthalmol Vis Sci 2023; 64:35. [PMID: 38133501 PMCID: PMC10746928 DOI: 10.1167/iovs.64.15.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/04/2023] [Indexed: 12/23/2023] Open
Abstract
Purpose Despite the centrality of the retinal pigment epithelium (RPE) in vision and retinopathy our picture of RPE morphology is incomplete. With a volumetric reconstruction of human RPE ultrastructure, we aim to characterize major membranous features including apical processes and their interactions with photoreceptor outer segments, basolateral infoldings, and the distribution of intracellular organelles. Methods A parafoveal retinal sample was acquired from a 21-year-old male organ donor. With serial block-face scanning electron microscopy, a tissue volume from the inner-outer segment junction to basal RPE was captured. Surface membranes and complete internal ultrastructure of an individual RPE cell were achieved with a combination of manual and automated segmentation methods. Results In one RPE cell, apical processes constitute 69% of the total cell surface area, through a dense network of over 3000 terminal branches. Single processes contact several photoreceptors. Basolateral infoldings facing the choriocapillaris resemble elongated filopodia and comprise 22% of the cell surface area. Membranous tubules and sacs of endoplasmic reticulum represent 20% of the cell body volume. A dense basal layer of mitochondria extends apically to partly overlap electron-dense pigment granules. Pores in the nuclear envelope form a distinct pattern of rows aligned with chromatin. Conclusions Specialized membranes at the apical and basal side of the RPE cell body involved in intercellular uptake and transport represent over 90% of the total surface area. Together with the polarized distribution of organelles within the cell body, these findings are relevant for retinal clinical imaging, therapeutic approaches, and disease pathomechanisms.
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Affiliation(s)
- Maximilian Lindell
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Deepayan Kar
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Aleksandra Sedova
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Yeon Jin Kim
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | - Orin S. Packer
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | | | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Mike Marsh
- Object Research Systems, Montreal, Quebec, Canada
| | - Dennis M. Dacey
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
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10
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Berlin A, Matney E, Jones SG, Clark ME, Swain TA, McGwin G, Martindale RM, Sloan KR, Owsley C, Curcio CA. Discernibility of the Interdigitation Zone (IZ), a Potential Optical Coherence Tomography (OCT) Biomarker for Visual Dysfunction in Aging. Curr Eye Res 2023; 48:1050-1056. [PMID: 37539829 PMCID: PMC10592305 DOI: 10.1080/02713683.2023.2240547] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 07/17/2023] [Accepted: 07/19/2023] [Indexed: 08/05/2023]
Abstract
PURPOSE Photoreceptor (PR) outer segments, retinal pigment epithelium apical processes, and inter-PR matrix contribute to the interdigitation zone (IZ) of optical coherence tomography (OCT). We hypothesize that this interface degrades over adulthood, in concert with a delay of rod mediated dark adaptation (RMDA). To explore this idea, we determined IZ discernibility and RMDA in younger and older adults. METHODS For this cross-sectional study, eyes of 20 young (20-30 years) and 40 older (≥60 years) participants with normal maculas according to the AREDS 9-step grading system underwent OCT imaging and RMDA testing at 5° superior to the fovea. Custom FIJI plugins enabled analysis for IZ discernibility at 9 eccentricities in 0.5 mm steps on one single horizontal B-scan through the fovea. Locations with discernible IZ met two criteria: visibility on B-scans and a distinct peak on a longitudinal reflectivity profile. The frequency of sites meeting both criteria was compared between both age groups and correlated with rod intercept time (RIT). RESULTS The median number of locations with discernible IZ was significantly higher (foveal, 4 vs. 0, p = 0.0099; extra-foveal 6 vs. 0, p < 0.001) in eyes of young (26 ± 3 years) compared to older (73 ± 5 years) participants. For the combined young and older sample, the higher frequency of discernible IZ was correlated with shorter RIT (faster dark adaptation) (rs = -0.56, p < 0.0001). This association was significant within young eyes (rs = -0.54; p = 0.0134) and not within older eyes (rs = -0.29, p = 0.706). CONCLUSIONS Results suggest that the interface between outer segments and apical processes degrades in normal aging, potentially contributing to delayed rod-mediated dark adaptation. More research is needed to verify an age-related association between IZ discernibility and rod-mediated dark adaptation. If confirmed in a large sample, IZ discernibility might prove to be a valuable biomarker and predictor for visual function in aging.
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Affiliation(s)
- Andreas Berlin
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
- University Hospital Würzburg, Würzburg, Germany
| | - Emily Matney
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| | - Skyler G. Jones
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| | - Mark E. Clark
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| | - Thomas A Swain
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| | - Gerald McGwin
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
- Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham AL USA
| | - Richard M. Martindale
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| | - Cynthia Owsley
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
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11
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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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Chen S, Abu-Qamar O, Kar D, Messinger JD, Hwang Y, Moult EM, Lin J, Baumal CR, Witkin A, Liang MC, Waheed NK, Curcio CA, Fujimoto JG. Ultrahigh resolution optical coherence tomography markers of normal aging and early age-related macular degeneration. OPHTHALMOLOGY SCIENCE 2023; 3:100277. [PMID: 36970115 PMCID: PMC10034509 DOI: 10.1016/j.xops.2023.100277] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 01/04/2023] [Accepted: 01/26/2023] [Indexed: 02/04/2023]
Abstract
Purpose Ultrahigh resolution spectral domain-OCT (UHR SD-OCT) enables in vivo visualization of micrometric structural markers which differentially associate with normal aging versus age-related macular degeneration (AMD). This study explores the hypothesis that UHR SD-OCT can detect and quantify sub-retinal pigment epithelium (RPE) deposits in early AMD, separating AMD pathology from normal aging. Design Prospective cross-sectional study. Participants A total of 53 nonexudative (dry) AMD eyes from 39 patients, and 63 normal eyes from 39 subjects. Methods Clinical UHR SD-OCT scans were performed using a high-density protocol. Exemplary high-resolution histology and transmission electron microscopy images were obtained from archive donor eyes. Three trained readers evaluated and labeled outer retina morphological features, including the appearance of a hyporeflective split within the RPE-RPE basal lamina (RPE-BL)-Bruch's membrane (BrM) complex on UHR brightness (B)-scans. A semi-automatic segmentation algorithm measured the thickness of the RPE-BL-BrM split/hyporeflective band. Main Outcome Measures Qualitative description of outer retinal morphological changes on UHR SD-OCT B-scans; the proportion of the RPE-BL-BrM complex with visible split (%) and the thickness of the resulting hyporeflective band (μm). Results In young normal eyes, UHR SD-OCT consistently revealed an RPE-BL-BrM split/hyporeflective band. Its visibility and thickness were less in eyes of advanced age. However, the split/hyporeflective band was again visible in early AMD eyes. Both qualitative reading and quantitative thickness measurements showed significantly elevated visibility and thickness of the RPE-BL-BrM split/hyporeflective in early AMD eyes compared to age-matched controls. Conclusions Our imaging results strongly support the hypothesis that appearance of the RPE-BL-BrM split/hyporeflective band in older subjects is dominated by the BL deposit, an indicator of early AMD well known from histology. Ultrahigh resolution SD-OCT can be used to investigate physiological aging as well as early AMD pathology in clinical imaging studies. Developing quantifiable markers associated with disease pathogenesis and progression can facilitate drug discovery, as well as reduce clinical trial times. Financial Disclosures Proprietary or commercial disclosure may be found after the references.
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13
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Kowalczuk L, Dornier R, Kunzi M, Iskandar A, Misutkova Z, Gryczka A, Navarro A, Jeunet F, Mantel I, Behar-Cohen F, Laforest T, Moser C. In Vivo Retinal Pigment Epithelium Imaging using Transscleral Optical Imaging in Healthy Eyes. OPHTHALMOLOGY SCIENCE 2022; 3:100234. [PMID: 36545259 PMCID: PMC9762198 DOI: 10.1016/j.xops.2022.100234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/05/2022]
Abstract
Objective To image healthy retinal pigment epithelial (RPE) cells in vivo using Transscleral OPtical Imaging (TOPI) and to analyze statistics of RPE cell features as a function of age, axial length (AL), and eccentricity. Design Single-center, exploratory, prospective, and descriptive clinical study. Participants Forty-nine eyes (AL: 24.03 ± 0.93 mm; range: 21.9-26.7 mm) from 29 participants aged 21 to 70 years (37.1 ± 13.3 years; 19 men, 10 women). Methods Retinal images, including fundus photography and spectral-domain OCT, AL, and refractive error measurements were collected at baseline. For each eye, 6 high-resolution RPE images were acquired using TOPI at different locations, one of them being imaged 5 times to evaluate the repeatability of the method. Follow-up ophthalmic examination was repeated 1 to 3 weeks after TOPI to assess safety. Retinal pigment epithelial images were analyzed with a custom automated software to extract cell parameters. Statistical analysis of the selected high-contrast images included calculation of coefficient of variation (CoV) for each feature at each repetition and Spearman and Mann-Whitney tests to investigate the relationship between cell features and eye and subject characteristics. Main Outcome Measures Retinal pigment epithelial cell features: density, area, center-to-center spacing, number of neighbors, circularity, elongation, solidity, and border distance CoV. Results Macular RPE cell features were extracted from TOPI images at an eccentricity of 1.6° to 16.3° from the fovea. For each feature, the mean CoV was < 4%. Spearman test showed correlation within RPE cell features. In the perifovea, the region in which images were selected for all participants, longer AL significantly correlated with decreased RPE cell density (R Spearman, Rs = -0.746; P < 0.0001) and increased cell area (Rs = 0.668; P < 0.0001), without morphologic changes. Aging was also significantly correlated with decreased RPE density (Rs = -0.391; P = 0.036) and increased cell area (Rs = 0.454; P = 0.013). Lower circular, less symmetric, more elongated, and larger cells were observed in those > 50 years. Conclusions The TOPI technology imaged RPE cells in vivo with a repeatability of < 4% for the CoV and was used to analyze the influence of physiologic factors on RPE cell morphometry in the perifovea of healthy volunteers. Financial Disclosures Proprietary or commercial disclosure may be found after the references.
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Key Words
- AF, autofluorescence
- AL, axial length
- AO, adaptive optics
- Adaptive Optics Transscleral Flood Illumination
- BCVA, best-corrected visual acuity
- CCS, center-to-center spacing
- CoV, coefficient of variation
- D, diopters
- FOV, field of view
- Healthy volunteers
- High resolution retinal imaging
- IOP, intraocular pressure
- NIR, near-infrared
- PRL, preferred retinal locus
- QC, quality criterion
- RE, refractive error
- RPE, retinal pigment epithelium
- Retinal Pigment Epithelium
- SD, standard deviation
- SLO, scanning laser ophthalmoscope
- TOPI, transscleral optical imaging
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Affiliation(s)
- Laura Kowalczuk
- Laboratory of Applied Photonic Devices, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland,Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland,Jules-Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland,Correspondence: Laura Kowalczuk, PhD, École Polytechnique Fédérale de Lausanne, School of Engineering, Institute of Electrical and Micro-engineering, Laboratory of Applied Photonics Devices, BM 4127, Station 17, CH-1015, Lausanne, Switzerland.
| | - Rémy Dornier
- Laboratory of Applied Photonic Devices, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Mathieu Kunzi
- Laboratory of Applied Photonic Devices, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Antonio Iskandar
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland,Jules-Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - Zuzana Misutkova
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland,Jules-Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - Aurélia Gryczka
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland,Jules-Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - Aurélie Navarro
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland,Jules-Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - Fanny Jeunet
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland,Jules-Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - Irmela Mantel
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland,Jules-Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - Francine Behar-Cohen
- Centre de Recherche des Cordeliers, Université Pierre et Marie Curie, Paris, France,INSERM U1138, USPC, Université de Paris-Cité, Sorbonne Université, Paris, France,Assistance Publique - Hôpitaux de Paris, Ophtalmopôle, Cochin Hospital, Paris, France,Université Paris Cité, Paris, France,Hôpital Foch, Suresnes, France
| | - Timothé Laforest
- Laboratory of Applied Photonic Devices, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Christophe Moser
- Laboratory of Applied Photonic Devices, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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14
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Chauhan P, Kho AM, FitzGerald P, Shibata B, Srinivasan VJ. Subcellular Comparison of Visible-Light Optical Coherence Tomography and Electron Microscopy in the Mouse Outer Retina. Invest Ophthalmol Vis Sci 2022; 63:10. [PMID: 35943734 PMCID: PMC9379865 DOI: 10.1167/iovs.63.9.10] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We employed in vivo, 1.0-µm axial resolution visible-light optical coherence tomography (OCT) and ex vivo electron microscopy (EM) to investigate three subcellular features in the mouse outer retina: reflectivity oscillations inner to band 1 (study 1); hyperreflective band 2, attributed to the ellipsoid zone or inner segment/outer segment (IS/OS) junction (study 2); and the hyperreflective retinal pigment epithelium (RPE) within band 4 (study 3). Methods Pigmented (C57BL/6J, n = 10) and albino (BALB/cJ, n = 3) mice were imaged in vivo. Enucleated eyes were processed for light and electron microscopy. Using well-accepted reference surfaces, we compared micrometer-scale axial reflectivity of visible-light OCT with subcellular organization, as revealed by 9449 annotated EM organelles and features across four pigmented eyes. Results In study 1, outer nuclear layer reflectivity peaks coincided with valleys in heterochromatin clump density (−0.34 ± 2.27 µm limits of agreement [LoA]). In study 2, band 2 depth on OCT and IS/OS junction depth on EM agreed (−0.57 ± 0.76 µm LoA), with both having similar distributions. In study 3, RPE electron dense organelle distribution did not agree with reflectivity in C57BL/6J mice, with OCT measures of RPE thickness exceeding those of EM (2.09 ± 0.89 µm LoA). Finally, RPE thickness increased with age in pigmented mice (slope = 0.056 µm/mo; P = 6.8 × 10−7). Conclusions Visible-light OCT bands arise from subcellular organization, enabling new measurements in mice. Quantitative OCT–EM comparisons may be confounded by hydration level, particularly in the OS and RPE. Caution is warranted in generalizing results to other species.
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Affiliation(s)
- Pooja Chauhan
- Department of Radiology, NYU Langone Health, New York, New York, United States
| | - Aaron M Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States
| | - Paul FitzGerald
- Department of Cell Biology and Human Anatomy, University of California Davis, Davis, California, United States
| | - Bradley Shibata
- Biological Electron Microscopy Facility, University of California Davis, Davis, California, United States
| | - Vivek J Srinivasan
- Department of Radiology, NYU Langone Health, New York, New York, United States.,Department of Biomedical Engineering, University of California Davis, Davis, California, United States.,Department of Ophthalmology, NYU Langone Health, New York, New York, United States
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15
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Blue-light fundus autofluorescence imaging of pigment epithelial detachments. Eye (Lond) 2022; 37:1191-1201. [PMID: 35581370 PMCID: PMC10102186 DOI: 10.1038/s41433-022-02076-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 03/18/2022] [Accepted: 04/19/2022] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Pigment epithelial detachments (PEDs) occur in association with various chorioretinal diseases. With respect to the broad clinical spectrum of PEDs we describe fundus autofluorescence (FAF) characteristics of PEDs. METHODS Ninety-three eyes of 66 patients (mean age 71.9 ± 11.1) with uni- or bilateral PED ( ≥ 350 µm) were included in a retrospective cross-sectional study. PEDs were secondary to age-related macular degeneration (n = 79), central serous chorioretinopathy (n = 7), polypoidal choroidal vasculopathy (n = 2), pattern dystrophy (n = 3) or idiopathic PED (n = 2). FAF images were recorded using confocal scanning laser ophthalmoscopy (488 nm excitation wavelength, detection of emission >500 nm). Diagnosis of PED was confirmed using spectral-domain optical coherence tomography. A qualitative FAF grading system was established, and grading was performed by two independent readers. RESULTS PEDs showed highly variable characteristics on FAF imaging. FAF within the area of PED was found to be irregular/granular (n = 59, 63.4%), increased (n = 28, 30.1%), decreased (n = 3, 3.2 %), or normal (n = 3, 3.2%). Accompanying FAF changes included condensation of macular pigment (n = 67, 72.0%), focally increased FAF at the PED apex (n = 14, 15.1%) or elsewhere (n = 52, 55.9%), focally decreased FAF (n = 23, 24.7%), a cartwheel-like pattern (n = 10, 10.8%), a doughnut sign (n = 6, 6.5%), and a halo of decreased FAF encircling the PED (completely n = 20, 21.5% or incompletely n = 20, 21.5%). CONCLUSIONS PEDs show a variety of abnormal patterns on FAF imaging. These changes in FAF signals may be secondary to morphological and metabolic alterations within corresponding retinal layers and do not necessarily correspond with the underlying PED subtype or a specific pathology.
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16
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Bindewald-Wittich A, Holz FG, Ach T, Fiorentzis M, Bechrakis NE, Willerding GD. Fundus Autofluorescence Imaging in Patients with Choroidal Melanoma. Cancers (Basel) 2022; 14:cancers14071809. [PMID: 35406581 PMCID: PMC8997882 DOI: 10.3390/cancers14071809] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 12/15/2022] Open
Abstract
Simple Summary The ocular fundus contains molecules that emit fluorescence when excited with light of an appropriate wavelength. Fundus autofluorescence imaging is based on the in vivo detection of intrinsic fluorescence and results in topographic autofluorescence mapping of the ocular fundus. In contrast to fluorescence angiography, where the fluorescing agents need to be administered intravenously, autofluorescence imaging is a non-invasive technique. Even though choroidal melanomas do not contain significant autofluorescent molecules themselves, they may lead to secondary alterations in neighbouring tissues with an impact on the autofluorescence signal recording. Fundus autofluorescence imaging in the context of choroidal melanoma is helpful for differential diagnosis and for monitoring variations over time in affected patients before and after treatment. Abstract Choroidal melanocytic lesions require reliable and precise clinical examination and diagnosis to differentiate benign choroidal nevi from choroidal melanoma, as the latter may become life-threatening through metastatic disease. To come to an accurate diagnosis, as well as for monitoring, and to assess the efficacy of therapy, various imaging modalities may be used, one of which is non-invasive fundus autofluorescence (FAF) imaging using novel high-resolution digital imaging technology. FAF imaging is based on the visualization of intrinsic fluorophores in the ocular fundus. Lipofuscin and melanolipofuscin within the postmitotic retinal pigment epithelium (RPE) cells represent the major fluorophores that contribute to the FAF signal. In addition, the presence or loss of absorbing molecular constituents may have an impact on the FAF signal. A choroidal melanoma can cause secondary retinal and RPE alterations that affect the FAF signal (e.g., occurrence of orange pigment). Therefore, FAF imaging supports multimodal imaging and gives additional information over and above conventional imaging modalities regarding retinal metabolism and RPE health status. This article summarises the features of FAF imaging and the role of FAF imaging in the context of choroidal melanoma, both before and following therapeutic intervention.
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Affiliation(s)
- Almut Bindewald-Wittich
- Augenkompetenz Zentren Heidenheim, 89518 Heidenheim, Germany
- Augenkompetenz Zentren Bopfingen, 73441 Bopfingen, Germany
- Department of Ophthalmology, University of Bonn, 53127 Bonn, Germany; (F.G.H.); (T.A.)
- Correspondence:
| | - Frank G. Holz
- Department of Ophthalmology, University of Bonn, 53127 Bonn, Germany; (F.G.H.); (T.A.)
| | - Thomas Ach
- Department of Ophthalmology, University of Bonn, 53127 Bonn, Germany; (F.G.H.); (T.A.)
| | - Miltiadis Fiorentzis
- Department of Ophthalmology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (M.F.); (N.E.B.)
| | - Nikolaos E. Bechrakis
- Department of Ophthalmology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (M.F.); (N.E.B.)
| | - Gregor D. Willerding
- Department of Ophthalmology, DRK Kliniken Berlin Westend, 14050 Berlin, Germany;
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17
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Brinkmann M, Bacci T, Kar D, Messinger JD, Sloan KR, Chen L, Hamann T, Wiest M, Freund KB, Zweifel S, Curcio CA. Histology and Clinical Lifecycle of Acquired Vitelliform Lesion, a Pathway to Advanced Age-Related Macular Degeneration. Am J Ophthalmol 2022; 240:99-114. [PMID: 35192790 PMCID: PMC9592119 DOI: 10.1016/j.ajo.2022.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 12/19/2022]
Abstract
PURPOSE To evaluate hypotheses about the role of acquired vitelliform lesion (AVL) in age-related macular degeneration pathophysiology. DESIGN Laboratory histology study; retrospective, observational case series. METHODS Two donor eyes in a research archive with AVL and age-related macular degeneration were analyzed with light and electron microscopy for AVL content at locations matched to ex vivo B-scans. A retrospective, observational clinical cohort study of 42 eyes of 30 patients at 2 referral clinics determined the frequency of optical coherence tomography features stratified by AVL fate. RESULTS Histologic and clinical cases showed subretinal drusenoid deposit and drusen. Ultrastructural AVL components in 2 donor eyes included retinal pigment epithelium (RPE) organelles (3%-22% of volume), outer segments (2%-10%), lipid droplets (0.2%-12%), and a flocculent material (57%-59%). Of 48 AVLs (mean follow-up 46 ± 39 months), 50% collapsed to complete RPE and outer retinal atrophy, 38% were stable, 10% resorbed, and 2% developed neovascularization. The Early Treatment Diabetic Retinopathy Study grid central subfield contained 77% of AVLs. Hyperreflective foci, ellipsoid zone disruption, and hyperreflective thickening of the RPE-basal lamina-Bruch membrane band were common at maximum AVL expansion. Collapsing and noncollapsing AVLs had different growth rates (rapid vs slow, respectively). CONCLUSIONS AVL deposits contain unexpectedly low levels of RPE organelles and outer segments. Subfoveal predilection, reflectivity on optical coherence tomography, hyperautofluorescence, yellow color, and growth-regression phases suggest dysregulation of lipid transfer pathways specific to cone photoreceptors and supporting cells in formation of AVL deposit, analogous to drusen and subretinal drusenoid deposit. Prediction of AVL outcomes via growth rates should be confirmed in larger clinical studies.
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Affiliation(s)
- Max Brinkmann
- Department of Ophthalmology and Visual Sciences (M.B., D.K., J.D.M., K.R.S., L.C., C.A.C.), University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA; Department of Ophthalmology (M.B., T.H., M.W., S.Z.), University Hospital Zurich, Zurich, Switzerland
| | - Tommaso Bacci
- Vitreous Retina Macula Consultants of New York (T.B., K.B.F.), New York University School of Medicine, New York, New York, USA
| | - Deepayan Kar
- Department of Ophthalmology and Visual Sciences (M.B., D.K., J.D.M., K.R.S., L.C., C.A.C.), University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA
| | - Jeffrey D Messinger
- Department of Ophthalmology and Visual Sciences (M.B., D.K., J.D.M., K.R.S., L.C., C.A.C.), University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA
| | - Kenneth R Sloan
- Department of Ophthalmology and Visual Sciences (M.B., D.K., J.D.M., K.R.S., L.C., C.A.C.), University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA
| | - Ling Chen
- Department of Ophthalmology and Visual Sciences (M.B., D.K., J.D.M., K.R.S., L.C., C.A.C.), University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA; First Affiliated Hospital of Chongqing Medical University (L.C.), Chongqing Key Laboratory of Ophthalmology, and Chongqing Eye Institute, Chongqing, China
| | - Timothy Hamann
- Department of Ophthalmology (M.B., T.H., M.W., S.Z.), University Hospital Zurich, Zurich, Switzerland
| | - Maximilian Wiest
- Department of Ophthalmology (M.B., T.H., M.W., S.Z.), University Hospital Zurich, Zurich, Switzerland
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York (T.B., K.B.F.), New York University School of Medicine, New York, New York, USA; LuEsther T. Mertz Retinal Research Center (K.B.F.), New York University School of Medicine, New York, New York, USA; Manhattan Eye, Ear and Throat Hospital, and the Department of Ophthalmology (K.B.F.), New York University School of Medicine, New York, New York, USA
| | - Sandrine Zweifel
- Department of Ophthalmology (M.B., T.H., M.W., S.Z.), University Hospital Zurich, Zurich, Switzerland; Department of Ophthalmology, University of Zurich (S.Z.), Zurich, Switzerland
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences (M.B., D.K., J.D.M., K.R.S., L.C., C.A.C.), University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA.
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18
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Olchawa MM, Herrnreiter AM, Skumatz CMB, Krzysztynska-Kuleta OI, Mokrzynski KT, Burke JM, Sarna TJ. The Inhibitory Effect of Blue Light on Phagocytic Activity by ARPE-19 Cells. Photochem Photobiol 2022; 98:1110-1121. [PMID: 35067943 DOI: 10.1111/php.13596] [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: 11/05/2021] [Revised: 01/12/2022] [Accepted: 01/18/2022] [Indexed: 11/30/2022]
Abstract
Chronic exposure of the retina to short wavelength visible light is a risk factor in pathogenesis of age-related macular degeneration. The proper functioning and survival of photoreceptors depends on efficient phagocytosis of photoreceptor outer segments (POS) by retinal pigment epithelium. The purpose of this study was to analyze the phagocytic activity of blue light-treated ARPE-19 cells, and to examine whether the observed effects could be related to altered levels of POS phagocytosis receptor proteins and/or to oxidation of cellular proteins and lipids. POS phagocytosis was measured by flow cytometry. Phagocytosis receptor proteins αv and β5 integrin subunits and Mer tyrosine kinase (MerTK) were quantified by western blotting. The intact functional heterodimer αvβ5 was quantified by immunoprecipitation followed by immunoblotting. Cellular protein and lipid hydroperoxides were analyzed by coumarin boronic acid probe and iodometric assay, respectively. Cell irradiation induced reversible inhibition of specific phagocytosis and transient reductions in phagocytosis receptor proteins. Full recovery of functional heterodimer was apparent. Significant photooxidation of cellular proteins and lipids was observed. The results indicate that transient inhibition of specific phagocytosis by blue light could be related to the reduction in phagocytosis receptor proteins. Such changes may arise from oxidative modifications of cell phagocytic machinery components.
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Affiliation(s)
- Magdalena M Olchawa
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Krakow, Poland.,Department of Ophthalmology, Eye Institute, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Anja M Herrnreiter
- Department of Ophthalmology, Eye Institute, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Christine M B Skumatz
- Department of Ophthalmology, Eye Institute, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Ophthalmology and Visual Sciences, Eye Institute, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Olga I Krzysztynska-Kuleta
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Krakow, Poland
| | - Krystian T Mokrzynski
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Krakow, Poland
| | - Janice M Burke
- Department of Ophthalmology, Eye Institute, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Emeritus Professor of Ophthalmology
| | - Tadeusz J Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Krakow, Poland
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19
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Bermond K, von der Emde L, Tarau IS, Bourauel L, Heintzmann R, Holz FG, Curcio CA, Sloan KR, Ach T. Autofluorescent Organelles Within the Retinal Pigment Epithelium in Human Donor Eyes With and Without Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2022; 63:23. [PMID: 35050307 PMCID: PMC8787573 DOI: 10.1167/iovs.63.1.23] [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: 12/13/2022] Open
Abstract
Purpose Human retinal pigment epithelium (RPE) cells contain lipofuscin, melanolipofuscin, and melanosome organelles that impact clinical autofluorescence (AF) imaging. Here, we quantified the effect of age-related macular degeneration (AMD) on granule count and histologic AF of RPE cell bodies. Methods Seven AMD-affected human RPE-Bruch's membrane flatmounts (early and intermediate = 3, late dry = 1, and neovascular = 3) were imaged at fovea, perifovea, and near periphery using structured illumination and confocal AF microscopy (excitation 488 nm) and compared to RPE-flatmounts with unremarkable macula (n = 7, >80 years). Subsequently, granules were marked with computer assistance, and classified by their AF properties. The AF/cell was calculated from confocal images. The total number of granules and AF/cell was analyzed implementing a mixed effect analysis of covariance (ANCOVA). Results A total of 152 AMD-affected RPE cells were analyzed (fovea = 22, perifovea = 60, and near-periphery = 70). AMD-affected RPE cells showed increased variability in size and a significantly increased granule load independent of the retinal location (fovea: P = 0.02, perifovea: P = 0.04, and near periphery: P < 0.01). The lipofuscin fraction of total organelles decreased and the melanolipofuscin fraction increased in AMD, at all locations (especially the fovea). AF was significantly lower in AMD-affected cells (fovea: <0.01, perifovea: <0.01, and near periphery: 0.02). Conclusions In AMD RPE, lipofuscin was proportionately lowest in the fovea, a location also known to be affected by accumulation of soft drusen and preservation of cone-mediated visual acuity. Enlarged RPE cell bodies displayed increased net granule count but diminished total AF. Future studies should also assess the impact on AF imaging of RPE apical processes containing melanosomes.
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Affiliation(s)
- Katharina Bermond
- Department of Ophthalmology, Ludwigshafen Hospital, Ludwigshafen, Germany
| | - Leon von der Emde
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
| | - Ioana-Sandra Tarau
- Department of Ophthalmology, University Hospital Würzburg, Würzburg, Germany
| | - Leonie Bourauel
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
| | - Rainer Heintzmann
- Leibniz Institute of Photonic Technology, Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Jena, Germany
| | - Frank G Holz
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
| | - Christine A Curcio
- Department of Ophthalmology, University of Alabama at Birmingham, Alabama, AL, United States
| | - Kenneth R Sloan
- Department of Ophthalmology, University of Alabama at Birmingham, Alabama, AL, United States
| | - Thomas Ach
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
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20
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Chen L, Cao D, Messinger JD, Ach T, Ferrara D, Freund KB, Curcio CA. Histology and clinical imaging lifecycle of black pigment in fibrosis secondary to neovascular age-related macular degeneration. Exp Eye Res 2022; 214:108882. [PMID: 34890604 PMCID: PMC8809488 DOI: 10.1016/j.exer.2021.108882] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE Melanotic cells with large spherical melanosomes, thought to originate from retinal pigment epithelium (RPE), are found in eyes with neovascular age-related macular degeneration (nvAMD). To generate hypotheses about RPE participation in fibrosis, we correlate histology to clinical imaging in an eye with prominent black pigment in fibrotic scar secondary to nvAMD. METHODS Macular findings in a white woman with untreated inactive subretinal fibrosis due to nvAMD in her right eye were documented over 9 years with color fundus photography (CFP), fundus autofluorescence (FAF) imaging, and optical coherence tomography (OCT). After death (age 90 years), this index eye was prepared for light and electron microscopy to analyze 7 discrete zones of pigmentation in the fibrotic scar. In additional donor eyes with nvAMD, we determined the frequency of black pigment (n = 36 eyes) and immuno-labeled for retinoid, immunologic, and microglial markers (RPE65, CD68, Iba1, TMEM119; n = 3 eyes). RESULTS During follow-up of the index eye, black pigment appeared and expanded within a hypoautofluorescent fibrotic scar. The blackest areas correlated to melanotic cells (containing large spherical melanosomes), some in multiple layers. Pale areas had sparse pigmented cells. Gray areas correlated to cells with RPE organelles entombed in the scar and multinucleate cells containing sparse large spherical melanosomes. In 94% of nvAMD donor eyes, hyperpigmentation was visible. Certain melanotic cells expressed some RPE65 and mostly CD68. Iba1 and TMEM119 immunoreactivity, found both in retina and scar, did not co-localize with melanotic cells. CONCLUSION Hyperpigmentation in CFP results from both organelle content and optical superimposition effects. Black fundus pigment in nvAMD is common and corresponds to cells containing numerous large spherical melanosomes and superimposition of cells containing sparse large melanosomes, respectively. Melanotic cells are molecularly distinct from RPE, consistent with a process of transdifferentiation. The subcellular source of spherical melanosomes remains to be determined. Detailed histology of nvAMD eyes will inform future studies using technologies for spatially resolved molecular discovery to generate new therapies for fibrosis. The potential of black pigment as a biomarker for fibrosis can be investigated in clinical multimodal imaging datasets.
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Affiliation(s)
- Ling Chen
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, PR China,Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Dongfeng Cao
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Jeffrey D. Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Thomas Ach
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
| | | | - K. Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, NY, USA,Department of Ophthalmology, New York University Grossman School of Medicine, New York, NY, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA,Corresponding author. 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, USA. (C.A. Curcio)
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21
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Panneels V, Diaz A, Imsand C, Guizar-Sicairos M, Müller E, Bittermann AG, Ishikawa T, Menzel A, Kaech A, Holler M, Grimm C, Schertler G. Imaging of retina cellular and subcellular structures using ptychographic hard X-ray tomography. J Cell Sci 2021; 134:272479. [PMID: 34494099 DOI: 10.1242/jcs.258561] [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: 02/15/2021] [Accepted: 09/01/2021] [Indexed: 11/20/2022] Open
Abstract
Ptychographic hard X-ray computed tomography (PXCT) is a recent method allowing imaging with quantitative electron-density contrast. Here, we imaged, at cryogenic temperature and without sectioning, cellular and subcellular structures of a chemically fixed and stained wild-type mouse retina, including axons and synapses, with complete isotropic 3D information over tens of microns. Comparison with tomograms of degenerative retina from a mouse model of retinitis pigmentosa illustrates the potential of this method for analyzing disease processes like neurodegeneration at sub-200 nm resolution. As a non-destructive imaging method, PXCT is very suitable for correlative imaging. Within the outer plexiform layer containing the photoreceptor synapses, we identified somatic synapses. We used a small region inside the X-ray-imaged sample for further high-resolution focused ion beam/scanning electron microscope tomography. The subcellular structures of synapses obtained with the X-ray technique matched the electron microscopy data, demonstrating that PXCT is a powerful scanning method for tissue volumes of more than 60 cells and sensitive enough for identification of regions as small as 200 nm, which remain available for further structural and biochemical investigations.
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Affiliation(s)
- Valerie Panneels
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Ana Diaz
- Division of Photon Science, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Cornelia Imsand
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, 8952 Schlieren, Switzerland
| | - Manuel Guizar-Sicairos
- Division of Photon Science, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Elisabeth Müller
- Division of Biology and Chemistry, Laboratory for Nanoscale Biology, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Anne Greet Bittermann
- ScopeM, Scientific Center for Optical and Electron Microscopy, ETH Zurich, 8093 Zurich, Switzerland
| | - Takashi Ishikawa
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, 5232 Villigen, Switzerland.,Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Andreas Menzel
- Division of Photon Science, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich, 8006 Zurich, Switzerland
| | - Mirko Holler
- Division of Photon Science, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Christian Grimm
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, 8952 Schlieren, Switzerland
| | - Gebhard Schertler
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, 5232 Villigen, Switzerland.,Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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22
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Meleppat RK, Ronning KE, Karlen SJ, Burns ME, Pugh EN, Zawadzki RJ. In vivo multimodal retinal imaging of disease-related pigmentary changes in retinal pigment epithelium. Sci Rep 2021; 11:16252. [PMID: 34376700 PMCID: PMC8355111 DOI: 10.1038/s41598-021-95320-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/20/2021] [Indexed: 02/08/2023] Open
Abstract
Melanosomes, lipofuscin, and melanolipofuscin are the three principal types of pigmented granules found in retinal pigment epithelium (RPE) cells. Changes in the density of melanosomes and lipofuscin in RPE cells are considered hallmarks of various retinal diseases, including Stargardt disease and age-related macular degeneration (AMD). Herein, we report the potential of an in vivo multimodal imaging technique based on directional back-scattering and short-wavelength fundus autofluorescence (SW-FAF) to study disease-related changes in the density of melanosomes and lipofuscin granules in RPE cells. Changes in the concentration of these granules in Abca4-/- mice (a model of Stargardt disease) relative to age-matched wild-type (WT) controls were investigated. Directional optical coherence tomography (dOCT) was used to assess melanosome density in vivo, whereas the autofluorescence (AF) images and emission spectra acquired with a spectrometer-integrated scanning laser ophthalmoscope (SLO) were used to characterize lipofuscin and melanolipofuscin granules in the same RPE region. Subcellular-resolution ex vivo imaging using confocal fluorescence microscopy and electron microscopy was performed on the same tissue region to visualize and quantify melanosomes, lipofuscin, and melanolipofuscin granules. Comparisons between in vivo and ex vivo results confirmed an increased concentration of lipofuscin granules and decreased concentration of melanosomes in the RPE of Abca4-/- mice, and provided an explanation for the differences in fluorescence and directionality of RPE scattering observed in vivo between the two mouse strains.
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Affiliation(s)
- Ratheesh K Meleppat
- UC Davis Eyepod Imaging Laboratory, University of California Davis, Davis, CA, 95616, USA
- Department of Cell Biology and Human Anatomy, University of California Davis, Davis, CA, 95616, USA
- Department of Ophthalmology and Vision Science, University of California Davis, Sacramento, CA, USA
| | - Kaitryn E Ronning
- Center for Neuroscience, University of California Davis, Davis, CA, 95618, USA
| | - Sarah J Karlen
- Department of Cell Biology and Human Anatomy, University of California Davis, Davis, CA, 95616, USA
| | - Marie E Burns
- Center for Neuroscience, University of California Davis, Davis, CA, 95618, USA
- Department of Ophthalmology and Vision Science, University of California Davis, Sacramento, CA, USA
| | - Edward N Pugh
- UC Davis Eyepod Imaging Laboratory, University of California Davis, Davis, CA, 95616, USA
- Department of Cell Biology and Human Anatomy, University of California Davis, Davis, CA, 95616, USA
| | - Robert J Zawadzki
- UC Davis Eyepod Imaging Laboratory, University of California Davis, Davis, CA, 95616, USA.
- Department of Cell Biology and Human Anatomy, University of California Davis, Davis, CA, 95616, USA.
- Department of Ophthalmology and Vision Science, University of California Davis, Sacramento, CA, USA.
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23
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Zhang T, Kho AM, Yiu G, Srinivasan VJ. Visible Light Optical Coherence Tomography (OCT) Quantifies Subcellular Contributions to Outer Retinal Band 4. Transl Vis Sci Technol 2021; 10:30. [PMID: 34003965 PMCID: PMC7998011 DOI: 10.1167/tvst.10.3.30] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Purpose To use visible light optical coherence tomography (OCT) to investigate subcellular reflectivity contributions to the outermost (4th) of the retinal hyperreflective bands visualized by current clinical near-infrared (NIR) OCT. Methods Visible light OCT, with 1.0 µm axial resolution, was performed in 28 eyes of 19 human subjects (21–57 years old) without history of ocular pathology. Two foveal and three extrafoveal hyperreflective zones were consistently depicted within band 4 in all eyes. The two outermost hyperreflective bands, occasionally visualized by NIR OCT, were presumed to be the retinal pigment epithelium (RPE) and Bruch's membrane (BM). RPE thickness, BM thickness, and RPE interior reflectivity were quantified topographically across the macula. Results A method for correcting RPE multiple scattering tails was found to both improve the Gaussian goodness-of-fit for the BM intensity profile and reduce the coefficient of variation of BM thickness in vivo. No major topographical differences in macular BM thickness were noted. RPE thickness decreased with increasing eccentricity. Visible light OCT signal intensity in the RPE was weighted to the apical side and attenuated more across the RPE in the fovea than peripherally. Conclusions Morphometry of the presumed RPE and BM bands is consistent with known anatomy. Weighting of RPE reflectivity toward the apical side suggests that melanosomes are the predominant contributors to RPE backscattering and signal attenuation in young eyes. Translational Relevance By enabling morphometric analysis of the RPE and BM, visible light OCT deciphers the main reflectivity contributions to outer retinal band 4, commonly visualized by commercial OCT systems.
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Affiliation(s)
- Tingwei Zhang
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Aaron M Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Glenn Yiu
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California, USA
| | - Vivek J Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA.,Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California, USA.,Department of Ophthalmology, New York University Langone Health, New York, New York, USA.,Department of Radiology, New York University Langone Health, New York, New York, USA.,Tech4Health Institute, New York University Langone Health, New York, New York, USA
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24
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Fujita A, Amari T, Ueda K, Azuma K, Inoue T, Komatsu K, Yamamoto M, Aoki N, Yamanari M, Sugiyama S, Aihara M, Kato S, Obata R. Three-Dimensional Distribution Of Fundus Depolarization and Associating Factors Measured Using Polarization-Sensitive Optical Coherence Tomography. Transl Vis Sci Technol 2021; 10:30. [PMID: 34003915 PMCID: PMC7900852 DOI: 10.1167/tvst.10.2.30] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose To investigate the three-dimensional distribution and associating demographic factors of depolarization, using polarization-sensitive optical coherence tomography (PS-OCT), to evaluate melanin pigmentation in the retinal pigment epithelium (RPE) and choroid in healthy eyes. Methods In total, 39 unaffected healthy eyes of 39 subjects were examined using a PS-OCT clinical prototype. The degree of depolarization, expressed as the polarimetric entropy, was assessed in the RPE, the superficial and the total choroid layer, especially in the center, the inner, or the outer areas centered at the fovea. The values and their association with the demographic data were analyzed. Near-infrared fundus autofluorescence (NIRAF) was also used, in the same manner, for the comparison. Twenty-eight of 39 eyes were measured twice to evaluate intrasession repeatability. Results Both the polarimetric entropy in the RPE and the gray level in NIRAF, decreased from the center to the periphery (P < 0.001). The polarimetric entropy in the RPE was significantly associated with age in each area (P ≤ 0.001). In the RPE and the superficial choroid, the polarimetric entropy was negatively associated with axial length in each area (P ≤ 0.002). The intraclass correlation coefficient of the polarimetric entropy in the same session was excellent in each area of the RPE, superficial choroid, or total choroid layer (0.94–0.98). Conclusions The distribution of fundus melanin pigment-related depolarization was evaluated using PS-OCT. The depolarization was associated with the subjects’ demographic data, such as age or axial length. Translational Relevance The presented information in healthy eyes provides an essential basis for the investigation into a variety of chorioretinal pathologies.
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Affiliation(s)
- Asahi Fujita
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan.,Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan
| | - Tatsuaki Amari
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan.,Eguchi Eye Hospital, Hakodate, Japan
| | - Kohei Ueda
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Keiko Azuma
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Tatsuya Inoue
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan.,Department of Ophthalmology, Yokohama City University Medical Center, Yokohama, Japan
| | - Kayoko Komatsu
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Motoshi Yamamoto
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | | | | | | | - Makoto Aihara
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Satoshi Kato
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Ryo Obata
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
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25
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Influence of lens opacities and cataract severity on quantitative fundus autofluorescence as a secondary outcome of a randomized clinical trial. Sci Rep 2021; 11:12685. [PMID: 34135449 PMCID: PMC8209039 DOI: 10.1038/s41598-021-92309-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/24/2021] [Indexed: 11/21/2022] Open
Abstract
The aim of this study is to investigate the impact of age-related lens opacities and advanced cataract, quantified by LOCS III grading, on quantitative autofluorescence (qAF) measurements in patients before and after cataract surgery. Images from a randomized controlled trial evaluating the impact of femtosecond-laser assisted cataract surgery (FLACS) on retinal thickness were analyzed post-hoc. One-hundred and twenty eyes from 60 consecutive patients with age-related cataract were included and assessed with qAF and optical coherence tomography (OCT) before, 1, 3 and 6 weeks after cataract surgery (randomized 1:1 to FLACS or phacoemulsification). LOCS III grading was performed before surgery. Pre- to post-surgical qAF values, as well as the impact of LOCS III gradings, surgery technique, gender, axial length and age on post-surgery qAF values was investigated using generalized linear mixed models. For this analysis, 106 eyes from 53 patients were usable. No difference in qAF was found between FLACS and phacoemulsification (p > 0.05) and results were pooled for the total cohort. Mean pre-surgical qAF was 89.45 ± 44.9 qAF units, with a significant mean increase of 178.4–191.6% after surgery (p < 0.001). No significant difference was found between the three follow-up visits after surgery (p > 0.05). Higher LOCS III cortical opacity quantifications were associated with a significantly greater increase in qAF after surgery (estimate: 98.56, p = 0.006) and nuclear opacities showed a trend toward an increased change (estimate: 48.8, p = 0.095). Considerable interactions were identified between baseline qAF and cortical opacities, nuclear opacities and posterior subcapsular opacities, as well as nuclear opacities and cortical opacities (p = 0.012, p = 0.064 and p = 0.069, respectively). Quantitative autofluorescence signals are significantly reconstituted after cataract surgery and LOCS III gradings are well associated with post-surgical qAF values. Careful consideration of age-related lens opacities is vital for the correct interpretation of qAF, especially in retinal diseases affecting the elderly. ClinicalTrials.gov Identifier: NCT03465124.
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26
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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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27
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Sura AA, Chen L, Messinger JD, Swain TA, McGwin G, Freund KB, Curcio CA. Measuring the Contributions of Basal Laminar Deposit and Bruch's Membrane in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2021; 61:19. [PMID: 33186466 PMCID: PMC7671869 DOI: 10.1167/iovs.61.13.19] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Purpose Basal laminar deposit (BLamD) is a consistent finding in age-related macular degeneration (AMD). We quantified BLamD thickness, appearance, and topography in eyes of aged donors with and without AMD and evaluated its relationship to other components of the retinal pigment epithelium-basal lamina/Bruch's membrane (RPE-BL-BrM) complex. Methods Donor eyes (n = 132) were classified as normal (n = 54), early to intermediate AMD (n = 24), geographic atrophy (GA; n = 13), and neovascular AMD (NV; n = 41). In high-resolution histology, we assessed RPE, BLamD, and BrM thicknesses and phenotypes at 3309 predefined locations in the central (foveal and perifovea) and superior (perifoveal) sections. Pre-mortem optical coherence tomography (OCT) imaging of a 90-year-old woman was compared to postmortem histopathology. Results In non-atrophic areas of AMD eyes, the RPE-BLamD is thick (normal = 13.7 µm, early-intermediate = 16.8 µm, GA = 17.4 µm, NV = 18.7 µm), because the BLamD is thick (normal = 0.3 µm, early-intermediate = 5.5 µm, GA = 4.1 µm, NV = 5.3 µm). RPE layer thickness is similar across these stages. Disease-associated variants of BLamD (thick, late, basal mounds) cluster subfoveally. A thick BLamD is visible on OCT as a hyporeflective split in the RPE-BL-BrM complex. BrM is thin (3.5 µm) in NV (normal = 4.2 µm, early to intermediate = 4.4 µm, and GA = 4.2 µm). Conclusions The RPE-BL-BrM complex is thick in AMD, driven by the accumulation and expansion of BLamD rather than expansion of either three-layer BrM, RPE-BL, or RPE. BLamD is clinically appreciable by OCT in some patients as a non-neovascular "split RPE-BL-BrM complex" or "double-layer sign." BLamD may contribute toward the formation and progression of high-risk drusen yet also exhibit protective properties.
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Affiliation(s)
- Amol A Sura
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Ling Chen
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States.,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, United States
| | - Thomas A Swain
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States.,Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Gerald McGwin
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States.,Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, New York, United States.,Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.,LuEsther T. Mertz Retinal Research Center, Manhattan Eye Ear and Throat Hospital, New York, New York, United States.,Department of Ophthalmology, NYU Langone School of Medicine, New York, New York, United States.,Columbia University College of Physicians and Surgeons, Harkness Eye Institute, New York, New York, United States
| | - 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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Nowzari F, Wang H, Khoradmehr A, Baghban M, Baghban N, Arandian A, Muhaddesi M, Nabipour I, Zibaii MI, Najarasl M, Taheri P, Latifi H, Tamadon A. Three-Dimensional Imaging in Stem Cell-Based Researches. Front Vet Sci 2021; 8:657525. [PMID: 33937378 PMCID: PMC8079735 DOI: 10.3389/fvets.2021.657525] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 03/19/2021] [Indexed: 12/14/2022] Open
Abstract
Stem cells have an important role in regenerative therapies, developmental biology studies and drug screening. Basic and translational research in stem cell technology needs more detailed imaging techniques. The possibility of cell-based therapeutic strategies has been validated in the stem cell field over recent years, a more detailed characterization of the properties of stem cells is needed for connectomics of large assemblies and structural analyses of these cells. The aim of stem cell imaging is the characterization of differentiation state, cellular function, purity and cell location. Recent progress in stem cell imaging field has included ultrasound-based technique to study living stem cells and florescence microscopy-based technique to investigate stem cell three-dimensional (3D) structures. Here, we summarized the fundamental characteristics of stem cells via 3D imaging methods and also discussed the emerging literatures on 3D imaging in stem cell research and the applications of both classical 2D imaging techniques and 3D methods on stem cells biology.
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Affiliation(s)
- Fariborz Nowzari
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Huimei Wang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Institute of Acupuncture and Moxibustion, Fudan Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Arezoo Khoradmehr
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Mandana Baghban
- Department of Obstetrics and Gynecology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Neda Baghban
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Alireza Arandian
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
| | - Mahdi Muhaddesi
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Iraj Nabipour
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Mohammad I. Zibaii
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
| | - Mostafa Najarasl
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
| | - Payam Taheri
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
| | - Hamid Latifi
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
- Department of Physics, Shahid Beheshti University, Tehran, Iran
| | - Amin Tamadon
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
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29
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Bermond K, Berlin A, Tarau IS, Wobbe C, Heintzmann R, Curcio CA, Sloan KR, Ach T. Characteristics of normal human retinal pigment epithelium cells with extremes of autofluorescence or intracellular granule count. ACTA ACUST UNITED AC 2021; 6. [PMID: 34291192 PMCID: PMC8291732 DOI: 10.21037/aes-2021-01] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background: Cells of the retinal pigment epithelium (RPE) accumulate different kinds of granules (lipofuscin, melanolipofuscin, melanosomes) within their cell bodies, with lipofuscin and melanolipofuscin being autofluorescent after blue light excitation. High amounts of lipofuscin granules within the RPE have been associated with the development of RPE cell death and age-related macular degeneration (AMD); however, this has not been confirmed in histology so far. Here, based on our previous dataset of RPE granule characteristics, we report the characteristics of RPE cells from human donor eyes that show either high or low numbers of intracellular granules or high or low autofluorescence (AF) intensities. Methods: RPE flatmounts of fifteen human donors were examined using high-resolution structured illumination microscopy (HR-SIM) and laser scanning microscopy (LSM). Autofluorescent granules were analyzed regarding AF phenotype and absolute number of granules. In addition, total AF intensity per cell and granule density (number of granules per cell area) were determined. For the final analysis, RPE cells with total granule number below 5th or above the 95th percentile, or a total AF intensity ± 1.5 standard deviations above or below the mean were included, and compared to the average RPE cell at the same location. Data are presented as mean ± standard deviation. Results: Within 420 RPE cells examined, 42 cells were further analyzed due to extremes regarding total granule numbers. In addition, 20 RPE cells had AF 1.5 standard deviations below, 28 RPE cells above the mean local AF intensity. Melanolipofuscin granules predominate in RPE cells with low granule content and low AF intensity. RPE cells with high granule content have nearly twice (1.8 times) as many granules as an average RPE cell. Conclusions: In normal eyes, outliers regarding autofluorescent granule load and AF intensity signals are rare among RPE cells, suggesting that granule deposition and subsequent AF follows intrinsic control mechanisms at a cellular level. The AF of a cell is related to the composition of intracellular granule types. Ongoing studies using AMD donor eyes will examine possible disease related changes in granule distribution and further put lipofuscińs role in aging and AMD further into perspective.
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Affiliation(s)
- Katharina Bermond
- Department of Ophthalmology, University Hospital Würzburg, Würzburg, Germany.,Department of Ophthalmology, Ludwigshafen Hospital, Ludwigshafen, Germany
| | - Andreas Berlin
- Department of Ophthalmology, University Hospital Würzburg, Würzburg, Germany
| | - Ioana-Sandra Tarau
- Department of Ophthalmology, University Hospital Würzburg, Würzburg, Germany
| | - Christina Wobbe
- Department of Ophthalmology, University Hospital Würzburg, Würzburg, Germany
| | - Rainer Heintzmann
- Leibniz Institute of Photonic Technology, Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Jena, Germany
| | - Christine A Curcio
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kenneth R Sloan
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Thomas Ach
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
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30
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Yamanari M, Mase M, Obata R, Matsuzaki M, Minami T, Takagi S, Yamamoto M, Miyamoto N, Ueda K, Koide N, Maeda T, Totani K, Aoki N, Hirami Y, Sugiyama S, Mandai M, Aihara M, Takahashi M, Kato S, Kurimoto Y. Melanin concentration and depolarization metrics measurement by polarization-sensitive optical coherence tomography. Sci Rep 2020; 10:19513. [PMID: 33177585 PMCID: PMC7658243 DOI: 10.1038/s41598-020-76397-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/23/2020] [Indexed: 11/16/2022] Open
Abstract
Imaging of melanin in the eye is important as the melanin is structurally associated with some ocular diseases, such as age-related macular degeneration. Although optical coherence tomography (OCT) cannot distinguish tissues containing the melanin from other tissues intrinsically, polarization-sensitive OCT (PS-OCT) can detect the melanin through spatial depolarization of the backscattered light from the melanin granules. Entropy is one of the depolarization metrics that can be used to detect malanin granules in PS-OCT and valuable quantitative information on ocular tissue abnormalities can be retrived by correlating entropy with the melanin concentration. In this study, we investigate a relationship between the melanin concentration and some depolarization metrics including the entropy, and show that the entropy is linearly proportional to the melanin concentration in double logarithmic scale when noise bias is corrected for the entropy. In addition, we also confirm that the entropy does not depend on the incident state of polarization using the experimental data, which is one of important attributes that depolarization metrics should have. The dependence on the incident state of polarization is also analyzed for other depolarization metrics.
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Affiliation(s)
| | - Mutsuki Mase
- Engineering Department, Tomey Corporation, Nagoya, Aichi, Japan
| | - Ryo Obata
- Department of Ophthalmology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Mitsuhiro Matsuzaki
- Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Hyogo, Japan.,Department of Ophthalmology, Kobe City Medical Centre General Hospital, Kobe, Hyogo, Japan
| | - Takahiro Minami
- Department of Ophthalmology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Seiji Takagi
- Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Hyogo, Japan.,Department of Ophthalmology, Kobe City Medical Centre General Hospital, Kobe, Hyogo, Japan
| | - Motoshi Yamamoto
- Department of Ophthalmology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Noriko Miyamoto
- Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Hyogo, Japan.,Department of Ophthalmology, Kobe City Medical Centre General Hospital, Kobe, Hyogo, Japan
| | - Koji Ueda
- Department of Ophthalmology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Naoshi Koide
- Laboratory for Retinal Regeneration, Riken Centre for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | - Tadao Maeda
- Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Hyogo, Japan.,Department of Ophthalmology, Kobe City Medical Centre General Hospital, Kobe, Hyogo, Japan.,Laboratory for Retinal Regeneration, Riken Centre for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | - Kota Totani
- Engineering Department, Tomey Corporation, Nagoya, Aichi, Japan
| | - Nobuyori Aoki
- Engineering Department, Tomey Corporation, Nagoya, Aichi, Japan
| | - Yasuhiko Hirami
- Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Hyogo, Japan.,Department of Ophthalmology, Kobe City Medical Centre General Hospital, Kobe, Hyogo, Japan.,Laboratory for Retinal Regeneration, Riken Centre for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | | | - Michiko Mandai
- Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Hyogo, Japan.,Laboratory for Retinal Regeneration, Riken Centre for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | - Makoto Aihara
- Department of Ophthalmology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masayo Takahashi
- Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Hyogo, Japan.,Laboratory for Retinal Regeneration, Riken Centre for Biosystems Dynamics Research, Kobe, Hyogo, Japan.,Vision Care Inc., Kobe, Hyogo, Japan
| | - Satoshi Kato
- Department of Ophthalmology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yasuo Kurimoto
- Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Hyogo, Japan.,Department of Ophthalmology, Kobe City Medical Centre General Hospital, Kobe, Hyogo, Japan.,Laboratory for Retinal Regeneration, Riken Centre for Biosystems Dynamics Research, Kobe, Hyogo, Japan
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31
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Keeling E, Chatelet DS, Tan NYT, Khan F, Richards R, Thisainathan T, Goggin P, Page A, Tumbarello DA, Lotery AJ, Ratnayaka JA. 3D-Reconstructed Retinal Pigment Epithelial Cells Provide Insights into the Anatomy of the Outer Retina. Int J Mol Sci 2020; 21:ijms21218408. [PMID: 33182490 PMCID: PMC7672636 DOI: 10.3390/ijms21218408] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 11/16/2022] Open
Abstract
The retinal pigment epithelium (RPE) is located between the neuroretina and the choroid, and plays a critical role in vision. RPE cells internalise outer segments (OS) from overlying photoreceptors in the daily photoreceptor renewal. Changes to RPE structure are linked with age and retinopathy, which has been described in the past by conventional 2D electron microscopy. We used serial block face scanning electron microscopy (SBF-SEM) to reconstruct RPE cells from the central mouse retina. Three-dimensional-reconstructed OS revealed the RPE to support large numbers of photoreceptors (90–216 per RPE cell). Larger bi-nucleate RPE maintained more photoreceptors, although their cytoplasmic volume was comparable to smaller mono-nucleate RPE supporting fewer photoreceptors. Scrutiny of RPE microvilli and interdigitating OS revealed the angle and surface area of contact between RPE and photoreceptors. Bi-nucleate RPE contained more mitochondria compared to mono-nucleate RPE. Furthermore, bi-nucleate cells contained larger sub-RPE spaces, supporting a likely association with disease. Use of perfusion-fixed tissues ensured the highest possible standard of preservation, providing novel insights into the 3D RPE architecture and changes linked with retinopathy. This study serves as a benchmark for comparing retinal tissues from donor eyes with age-related macular degeneration (AMD) and other retinopathies.
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Affiliation(s)
- Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK; (E.K.); (N.Y.T.T.); (F.K.); (R.R.); (T.T.); (A.J.L.)
| | - David S. Chatelet
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton SO16 6YD, UK; (D.S.C.); (P.G.); (A.P.)
| | - Nicole Y. T. Tan
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK; (E.K.); (N.Y.T.T.); (F.K.); (R.R.); (T.T.); (A.J.L.)
| | - Farihah Khan
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK; (E.K.); (N.Y.T.T.); (F.K.); (R.R.); (T.T.); (A.J.L.)
| | - Rhys Richards
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK; (E.K.); (N.Y.T.T.); (F.K.); (R.R.); (T.T.); (A.J.L.)
| | - Thibana Thisainathan
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK; (E.K.); (N.Y.T.T.); (F.K.); (R.R.); (T.T.); (A.J.L.)
| | - Patricia Goggin
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton SO16 6YD, UK; (D.S.C.); (P.G.); (A.P.)
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton SO16 6YD, UK; (D.S.C.); (P.G.); (A.P.)
| | - David A. Tumbarello
- Biological Sciences, Faculty of Environmental and Life Sciences, Life Sciences Building 85, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK;
| | - Andrew J. Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK; (E.K.); (N.Y.T.T.); (F.K.); (R.R.); (T.T.); (A.J.L.)
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - J. Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK; (E.K.); (N.Y.T.T.); (F.K.); (R.R.); (T.T.); (A.J.L.)
- Correspondence: ; Tel.: +44-238120-8183
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32
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Zhang T, Kho AM, Zawadzki RJ, Jonnal RS, Yiu G, Srinivasan VJ. Visible light OCT improves imaging through a highly scattering retinal pigment epithelial wall. OPTICS LETTERS 2020; 45:5945-5948. [PMID: 33137037 PMCID: PMC7864585 DOI: 10.1364/ol.405398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/21/2020] [Indexed: 05/15/2023]
Abstract
Here we provide a counter-example to the conventional wisdom in biomedical optics that longer wavelengths aid deeper imaging in tissue. Specifically, we investigate visible light optical coherence tomography of Bruch's membrane (BM) in the non-pathologic eyes of humans and two mouse strains. Surprisingly, we find that shorter visible wavelengths improve the visualization of BM in pigmented eyes, where it is located behind a highly scattering layer of melanosomes in the retinal pigment epithelium (RPE). Monte Carlo simulations of radiative transport suggest that, while absorption and scattering are higher at shorter wavelengths, detected multiply scattered light from the RPE is preferentially attenuated relative to detected backscattered light from the BM.
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Affiliation(s)
- Tingwei Zhang
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
| | - Aaron M. Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
| | - Robert J. Zawadzki
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, USA
| | - Ravi S. Jonnal
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, USA
| | - Glenn Yiu
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, USA
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, USA
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33
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The Effect of Antioxidants on Photoreactivity and Phototoxic Potential of RPE Melanolipofuscin Granules from Human Donors of Different Age. Antioxidants (Basel) 2020; 9:antiox9111044. [PMID: 33114498 PMCID: PMC7693403 DOI: 10.3390/antiox9111044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/16/2020] [Accepted: 10/19/2020] [Indexed: 11/17/2022] Open
Abstract
One of the most prominent age-related changes of retinal pigment epithelium (RPE) is the accumulation of melanolipofuscin granules, which could contribute to oxidative stress in the retina. The purpose of this study was to determine the ability of melanolipofuscin granules from younger and older donors to photogenerate reactive oxygen species, and to examine if natural antioxidants could modify the phototoxic potential of this age pigment. Electron paramagnetic resonance (EPR) oximetry, EPR-spin trapping, and time-resolved detection of near-infrared phosphorescence were employed for measuring photogeneration of superoxide anion and singlet oxygen by melanolipofuscin isolated from younger and older human donors. Phototoxicity mediated by internalized melanolipofuscin granules with and without supplementation with zeaxanthin and α-tocopherol was analyzed in ARPE-19 cells by determining cell survival, oxidation of cellular proteins, organization of the cell cytoskeleton, and the cell specific phagocytic activity. Supplementation with antioxidants reduced aerobic photoreactivity and phototoxicity of melanolipofuscin granules. The effect was particularly noticeable for melanolipofuscin mediated inhibition of the cell phagocytic activity. Antioxidants decreased the extent of melanolipofuscin-dependent oxidation of cellular proteins and disruption of the cell cytoskeleton. Although melanolipofuscin might be involved in chronic phototoxicity of the aging RPE, natural antioxidants could partially ameliorate these harmful effects.
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34
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Bermond K, Wobbe C, Tarau IS, Heintzmann R, Hillenkamp J, Curcio CA, Sloan KR, Ach T. Autofluorescent Granules of the Human Retinal Pigment Epithelium: Phenotypes, Intracellular Distribution, and Age-Related Topography. Invest Ophthalmol Vis Sci 2020; 61:35. [PMID: 32433758 PMCID: PMC7405767 DOI: 10.1167/iovs.61.5.35] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The human retinal pigment epithelium (RPE) accumulates granules significant for autofluorescence imaging. Knowledge of intracellular accumulation and distribution is limited. Using high-resolution microscopy techniques, we determined the total number of granules per cell, intracellular distribution, and changes related to retinal topography and age. Methods RPE cells from the fovea, perifovea, and near-periphery of 15 human RPE flat mounts were imaged using structured illumination microscopy (SIM) and confocal fluorescence microscopy in young (≤51 years, n = 8) and older (>80 years, n = 7) donors. Using custom FIJI plugins, granules were marked with computer assistance, classified based on morphological and autofluorescence properties, and analyzed with regard to intracellular distribution, total number per cell, and granule density. Results A total of 193,096 granules in 450 RPE cell bodies were analyzed. Based on autofluorescence properties, size, and composition, the RPE granules exhibited nine different phenotypes (lipofuscin, two; melanolipofuscin, five; melanosomes, two), distinguishable by SIM. Overall, lipofuscin (low at the fovea but increases with eccentricity and age) and melanolipofuscin (equally distributed at all three locations with no age-related changes) were the major granule types. Melanosomes were under-represented due to suboptimal visualization of apical processes in flat mounts. Conclusions Low lipofuscin and high melanolipofuscin content within foveal RPE cell bodies and abundant lipofuscin at the perifovea suggest a different genesis, plausibly related to the population of overlying photoreceptors (fovea, cones only; perifovea, highest rod density). This systematic analysis provides further insight into RPE cell and granule physiology and links granule load to cell autofluorescence, providing a subcellular basis for the interpretation of clinical fundus autofluorescence.
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35
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Miller DT, Kurokawa K. Cellular-Scale Imaging of Transparent Retinal Structures and Processes Using Adaptive Optics Optical Coherence Tomography. Annu Rev Vis Sci 2020; 6:115-148. [PMID: 32609578 PMCID: PMC7864592 DOI: 10.1146/annurev-vision-030320-041255] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
High-resolution retinal imaging is revolutionizing how scientists and clinicians study the retina on the cellular scale. Its exquisite sensitivity enables time-lapse optical biopsies that capture minute changes in the structure and physiological processes of cells in the living eye. This information is increasingly used to detect disease onset and monitor disease progression during early stages, raising the possibility of personalized eye care. Powerful high-resolution imaging tools have been in development for more than two decades; one that has garnered considerable interest in recent years is optical coherence tomography enhanced with adaptive optics. State-of-the-art adaptive optics optical coherence tomography (AO-OCT) makes it possible to visualize even highly transparent cells and measure some of their internal processes at all depths within the retina, permitting reconstruction of a 3D view of the living microscopic retina. In this review, we report current AO-OCT performance and its success in visualizing and quantifying these once-invisible cells in human eyes.
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Affiliation(s)
- Donald T Miller
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA; ,
| | - Kazuhiro Kurokawa
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA; ,
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36
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Cozzi M, Viola F, Belotti M, Cigada M, Cherepanoff S, Staurenghi G, Invernizzi A. The In Vivo Correlation between Retinal Pigment Epithelium Thickness and Quantitative Fundus Autofluorescence in a White Population. Ophthalmol Retina 2020; 5:365-373. [PMID: 32763425 DOI: 10.1016/j.oret.2020.07.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 07/24/2020] [Accepted: 07/31/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE To investigate the influence of age on the thickness of the retinal pigment epithelium (RPE)/Bruch's membrane (BM) complex and the quantitative autofluorescence (qAF) and to study the possible correlation existing between these 2 parameters in a healthy White population. DESIGN Cross-sectional, observational study. PARTICIPANTS Healthy White volunteers aged 18 to 65 years. METHODS All subjects underwent spectral domain OCT (SD-OCT) and qAF imaging with the Heidelberg HRA-Spectralis (Heidelberg Engineering, Heidelberg, Germany). Spectral domain OCT images were analyzed using the in-built graph-based automatic segmentation algorithm for single retinal layer identification to assess RPE/BM complex thickness in vivo. The thickness values of both inner and outer rings of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid, generated by the software using the "RPE" segmentation, were averaged to obtain a single RPE/BM complex thickness value in each eye. Quantitative autofluorescence images were also evaluated using a dedicated software. The qAF values of 8 subfields forming a ring centered onto the fovea were collected and averaged to obtain a single qAF value (qAF8) in each eye. The correlation among the RPE/BM complex thickness, the qAF value, and the age of the subjects was investigated. MAIN OUTCOME MEASURES The in vivo correlation between RPE/BM complex thickness and qAF. RESULTS A total of 105 eyes from 105 subjects (mean age, 42.1 ± 13.9 years; range, 18-65) were included in the analysis. The mean RPE/BM complex thickness significantly increased with age (r = 0.33, P = 0.0006). The values of qAF also positively increased with age (P < 0.0001). A significant correlation was found between qAF and RPE/BM complex thickness (r = 0.27, P = 0.004). After adjusting for age, iris color, and gender, the correlation remained significant only for subjects aged less than 40 years (P = 0.009). CONCLUSIONS BM complex thickness was significantly co/BM complex thickness increased with age in a healthy White population. A similar increase was found for qAF values. After adjusting for age and iris color, qAF and RPE/BM complex thickness were still correlated in subjects aged less than 40 years. The RPE/BM complex thickness could reflect the lipofuscin/melanolipofuscin accumulation in normal subjects, adding great interest in RPE cell biology.
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Affiliation(s)
- Mariano Cozzi
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco," Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Francesco Viola
- Department of Clinical Sciences and Community Health, University of Milan, Ophthalmological Unit, IRCCS-C à Granda Foundatione Ospedale Maggiore Policlinico, Milan, Italy
| | - Maria Belotti
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco," Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Mario Cigada
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco," Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Svetlana Cherepanoff
- The University of Sydney, Save Sight Institute, Discipline of Ophthalmology, Sydney Medical School, Sydney, New South Wales, Australia
| | - Giovanni Staurenghi
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco," Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Alessandro Invernizzi
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco," Luigi Sacco Hospital, University of Milan, Milan, Italy; The University of Sydney, Save Sight Institute, Discipline of Ophthalmology, Sydney Medical School, Sydney, New South Wales, Australia.
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Pollreisz A, Neschi M, Sloan KR, Pircher M, Mittermueller T, Dacey DM, Schmidt-Erfurth U, Curcio CA. Atlas of Human Retinal Pigment Epithelium Organelles Significant for Clinical Imaging. Invest Ophthalmol Vis Sci 2020; 61:13. [PMID: 32648890 PMCID: PMC7425708 DOI: 10.1167/iovs.61.8.13] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 04/27/2020] [Indexed: 02/07/2023] Open
Abstract
Purpose To quantify organelles impacting imaging in the cell body and intact apical processes of human retinal pigment epithelium (RPE), including melanosomes, lipofuscin-melanolipofuscin (LM), mitochondria, and nuclei. Methods A normal perifovea of a 21-year-old white male was preserved after rapid organ recovery. An aligned image stack was generated using serial block-face scanning electron microscopy and was annotated by expert readers (TrakEM, ImageJ). Acquired measures included cell body and nuclear volume (n = 17); organelle count in apical processes (n = 17) and cell bodies (n = 8); distance of cell body organelles along a normalized apical-basal axis (n = 8); and dimensions of organelle-bounding boxes in apical processes in selected subsamples of cell bodies and apical processes. Results In 2661 sections through 17 cells, apical processes contained 65 ± 24 melanosomes in mononucleate (n = 15) and 131 ± 28 in binucleate cells (n = 2). Cell bodies contained 681 ± 153 LM and 734 ± 170 mitochondria. LM was excluded from the basal quartile, and mitochondria from the apical quartile. Lengths of melanosomes, LM, and mitochondria, respectively were 2305 ± 528, 1320 ± 574, and 1195 ± 294 nm. The ratio of cell body to nucleus volume was 4.6 ± 0.4. LM and mitochondria covered 75% and 63%, respectively, of the retinal imaging plane. Conclusions Among RPE signal sources for optical coherence tomography, LM and mitochondria are the most numerous reflective cell body organelles. These and our published data show that most melanosomes are in apical processes. Overlapping LM and previously mitochondria cushions may support multiple reflective bands in cell bodies. This atlas of subcellular reflectivity sources can inform development of advanced optical coherence tomography technologies.
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Affiliation(s)
- Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Martina Neschi
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Department of Computer Science, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Michael Pircher
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | | | - Dennis M. Dacey
- Department of Biologic Structure, University of Washington, Seattle, Washington, United States
| | | | - 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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A2E Distribution in RPE Granules in Human Eyes. Molecules 2020; 25:molecules25061413. [PMID: 32244898 PMCID: PMC7144568 DOI: 10.3390/molecules25061413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/11/2020] [Accepted: 03/17/2020] [Indexed: 12/30/2022] Open
Abstract
A2E (N-retinylidene-N-retinylethanolamine) is a major fluorophore in the RPE (retinal pigment epithelium). To identify and characterize A2E-rich RPE lipofuscin, we fractionated RPE granules from human donor eyes into five fractions (F1–F5 in ascending order of density) by discontinuous sucrose density gradient centrifugation. The dry weight of each fraction was measured and A2E was quantified by liquid chromatography/mass spectrometry (LC/MS) using a synthetic A2E homolog as a standard. Autofluorescence emission was characterized by a customer-built spectro-fluorometer system. A significant A2E level was detected in every fraction, and the highest level was found in F1, a low-density fraction that makes up half of the total weight of all RPE granules, contains 67% of all A2E, and emits 75% of projected autofluorescence by all RPE granules. This group of RPE granules, not described previously, is therefore the most abundant RPE lipofuscin granule population. A progressive decrease in autofluorescence was observed from F2 to F4, whereas no autofluorescence emission was detected from the heavily pigmented F5. The identification of a novel and major RPE lipofuscin population could have significant implications in our understanding of A2E and lipofuscin in human RPE.
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Zhang Q, Presswalla F, Calton M, Charniga C, Stern J, Temple S, Vollrath D, Zacks DN, Ali RR, Thompson DA, Miller JML. Highly Differentiated Human Fetal RPE Cultures Are Resistant to the Accumulation and Toxicity of Lipofuscin-Like Material. Invest Ophthalmol Vis Sci 2019; 60:3468-3479. [PMID: 31408109 PMCID: PMC6692057 DOI: 10.1167/iovs.19-26690] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose The accumulation of undigestible autofluorescent material (UAM), termed lipofuscin in vivo, is a hallmark of aged RPE. Lipofuscin derives, in part, from the incomplete degradation of phagocytized photoreceptor outer segments (OS). Whether this accumulated waste is toxic is unclear. We therefore investigated the effects of UAM in highly differentiated human fetal RPE (hfRPE) cultures. Methods Unmodified and photo-oxidized OS were fed daily to confluent cultures of ARPE-19 RPE or hfRPE. The emission spectrum, composition, and morphology of resulting UAM were measured and compared to in vivo lipofuscin. Effects of UAM on multiple RPE phenotypes were assessed. Results Compared to ARPE-19, hfRPE were markedly less susceptible to UAM buildup. Accumulated UAM in hfRPE initially resembled the morphology of lipofuscin from AMD eyes, but compacted and shifted spectrum over time to resemble lipofuscin from healthy aged human RPE. UAM accumulation mildly reduced transepithelial electrical resistance, ketogenesis, certain RPE differentiation markers, and phagocytosis efficiency, while inducing senescence and rare, focal pockets of epithelial-mesenchymal transition. However, it had no effects on mitochondrial oxygen consumption rate, certain other RPE differentiation markers, secretion of drusen components or polarity markers, nor cell death. Conclusions hfRPE demonstrates a remarkable resistance to UAM accumulation, suggesting mechanisms for efficient OS processing that may be lost in other RPE culture models. Furthermore, while UAM alters hfRPE phenotype, the effects are modest, consistent with conflicting reports in the literature on the toxicity of lipofuscin. Our results suggest that healthy RPE may adequately adapt to and tolerate lipofuscin accumulation.
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Affiliation(s)
- Qitao Zhang
- Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Feriel Presswalla
- Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Melissa Calton
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States
| | - Carol Charniga
- Neural Stem Cell Institute, Rensselaer, New York, United States
| | - Jeffrey Stern
- Neural Stem Cell Institute, Rensselaer, New York, United States
| | - Sally Temple
- Neural Stem Cell Institute, Rensselaer, New York, United States
| | - Douglas Vollrath
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States
| | - David N Zacks
- Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Robin R Ali
- Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States.,UCL Institute of Ophthalmology, London, United Kingdom
| | - Debra A Thompson
- Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Jason M L Miller
- Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
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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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Genetic LAMP2 deficiency accelerates the age-associated formation of basal laminar deposits in the retina. Proc Natl Acad Sci U S A 2019; 116:23724-23734. [PMID: 31699817 PMCID: PMC6876195 DOI: 10.1073/pnas.1906643116] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Extracellular tissue debris accumulates with aging and in the most prevalent central-vision-threatening eye disorder, age-related macular degeneration (AMD). In this work, we discovered that lysosome-associated membrane protein-2 (LAMP2), a glycoprotein that plays a critical role in lysosomal biogenesis and maturation of autophagosomes/phagosomes, is preferentially expressed in the outermost, neuroepithelial layer of the retina, the retinal pigment epithelium (RPE), and contributes to the prevention of ultrastructural changes in extracellular basolaminar deposits including lipids and apolipoproteins. LAMP2 thus appears to play an important role in RPE biology, and its apparent decrease with aging and in AMD specimens suggests that its deficiency may accelerate the basolaminar deposit formation and RPE dysfunction seen in these conditions. The early stages of age-related macular degeneration (AMD) are characterized by the accumulation of basal laminar deposits (BLamDs). The mechanism for BLamDs accumulating between the retinal pigment epithelium (RPE) and its basal lamina remains elusive. Here we examined the role in AMD of lysosome-associated membrane protein-2 (LAMP2), a glycoprotein that plays a critical role in lysosomal biogenesis and maturation of autophagosomes/phagosomes. LAMP2 was preferentially expressed by RPE cells, and its expression declined with age. Deletion of the Lamp2 gene in mice resulted in age-dependent autofluorescence abnormalities of the fundus, thickening of Bruch’s membrane, and the formation of BLamDs, resembling histopathological changes occurring in AMD. Moreover, LAMP2-deficient mice developed molecular signatures similar to those found in human AMD—namely, the accumulation of APOE, APOA1, clusterin, and vitronectin—adjacent to BLamDs. In contrast, collagen 4, laminin, and fibronectin, which are extracellular matrix proteins constituting RPE basal lamina and Bruch’s membrane were reduced in Lamp2 knockout (KO) mice. Mechanistically, retarded phagocytic degradation of photoreceptor outer segments compromised lysosomal degradation and increased exocytosis in LAMP2-deficient RPE cells. The accumulation of BLamDs observed in LAMP2-deficient mice was eventually followed by loss of the RPE and photoreceptors. Finally, we observed loss of LAMP2 expression along with ultramicroscopic features of abnormal phagocytosis and exocytosis in eyes from AMD patients but not from control individuals. Taken together, these results indicate an important role for LAMP2 in RPE function in health and disease, suggesting that LAMP2 reduction may contribute to the formation of BLamDs in AMD.
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Liu Z, Kurokawa K, Hammer DX, Miller DT. In vivo measurement of organelle motility in human retinal pigment epithelial cells. BIOMEDICAL OPTICS EXPRESS 2019; 10:4142-4158. [PMID: 31453000 PMCID: PMC6701538 DOI: 10.1364/boe.10.004142] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/24/2019] [Accepted: 06/24/2019] [Indexed: 05/18/2023]
Abstract
Retinal pigment epithelial (RPE) cells are well known to play a central role in the progression of numerous retinal diseases. Changes in the structure and function of these cells thus may serve as sensitive biomarkers of disease onset. While in vivo studies have focused on structural changes, functional ones may better capture cell health owing to their more direct connection to cell physiology. In this study, we developed a method based on adaptive optics optical coherence tomography (AO-OCT) and speckle field dynamics for characterizing organelle motility in individual RPE cells. We quantified the dynamics in terms of an exponential decay time constant, the time required for the speckle field to decorrelate. Using seven normal subjects, we found the RPE speckle field to decorrelate in about 5 s. This result has two fundamental implications for future clinical use. First, it establishes a path for generating a normative baseline to which motility of diseased RPE cells can be compared. Second, it predicts an AO-OCT image acquisition time that is 36 times faster than used in our earlier report for individuating RPE cells, thus a major improvement in clinical efficacy.
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Affiliation(s)
- Zhuolin Liu
- Center for Devices and Radiological Health (CDRH), U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA
| | - Kazuhiro Kurokawa
- School of Optometry, Indiana University, 800 East Atwater Avenue, Bloomington, IN 47405, USA
| | - Daniel X. Hammer
- Center for Devices and Radiological Health (CDRH), U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA
| | - Donald T. Miller
- School of Optometry, Indiana University, 800 East Atwater Avenue, Bloomington, IN 47405, USA
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The Cytoskeleton of the Retinal Pigment Epithelium: from Normal Aging to Age-Related Macular Degeneration. Int J Mol Sci 2019; 20:ijms20143578. [PMID: 31336621 PMCID: PMC6678077 DOI: 10.3390/ijms20143578] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/15/2019] [Accepted: 07/18/2019] [Indexed: 12/15/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a unique epithelium, with major roles which are essential in the visual cycle and homeostasis of the outer retina. The RPE is a monolayer of polygonal and pigmented cells strategically placed between the neuroretina and Bruch membrane, adjacent to the fenestrated capillaries of the choriocapillaris. It shows strong apical (towards photoreceptors) to basal/basolateral (towards Bruch membrane) polarization. Multiple functions are bound to a complex structure of highly organized and polarized intracellular components: the cytoskeleton. A strong connection between the intracellular cytoskeleton and extracellular matrix is indispensable to maintaining the function of the RPE and thus, the photoreceptors. Impairments of these intracellular structures and the regular architecture they maintain often result in a disrupted cytoskeleton, which can be found in many retinal diseases, including age-related macular degeneration (AMD). This review article will give an overview of current knowledge on the molecules and proteins involved in cytoskeleton formation in cells, including RPE and how the cytoskeleton is affected under stress conditions—especially in AMD.
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Meleppat RK, Zhang P, Ju MJ, Manna SK, Jian Y, Pugh EN, Zawadzki RJ. Directional optical coherence tomography reveals melanin concentration-dependent scattering properties of retinal pigment epithelium. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-10. [PMID: 31254332 PMCID: PMC6977406 DOI: 10.1117/1.jbo.24.6.066011] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/30/2019] [Indexed: 05/18/2023]
Abstract
Optical coherence tomography (OCT) is a powerful tool in ophthalmology that provides in vivo morphology of the retinal layers and their light scattering properties. The directional (angular) reflectivity of the retinal layers was investigated with focus on the scattering from retinal pigment epithelium (RPE). The directional scattering of the RPE was studied in three mice strains with three distinct melanin concentrations: albino (BALB/c), agouti (129S1/SvlmJ), and strongly pigmented (C57BL/6J). The backscattering signal strength was measured with a directional OCT system in which the pupil entry position of the narrow OCT beam can be varied across the dilated pupil of the eyes of the mice. The directional reflectivity of other retinal melanin-free layers, including the internal and external limiting membranes, and Bruch's membrane (albinos) were also measured and compared between the strains. The intensity of light backscattered from these layers was found highly sensitive to the angle of illumination, whereas the inner/outer segment (IS/OS) junctions showed a reduced sensitivity. The reflections from the RPE are largely insensitive in highly pigmented mice. The differences in directional scattering between strains shows that directionality decreases with an increase in melanin concentrations in RPE, suggesting increasing contribution of Mie scattering by melanosomes.
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Affiliation(s)
- Ratheesh K. Meleppat
- University of California Davis, UC Davis Eyepod, Department of Cell Biology and Human Anatomy, Davis, California, United States
| | - Pengfei Zhang
- University of California Davis, UC Davis Eyepod, Department of Cell Biology and Human Anatomy, Davis, California, United States
| | - Myeong Jin Ju
- Simon Fraser University, School of Engineering Science, Burnaby, British Columbia, Canada
| | - Suman K. Manna
- University of California Davis, UC Davis Eyepod, Department of Cell Biology and Human Anatomy, Davis, California, United States
| | - Yifan Jian
- Oregon Science and Health University, Casey Eye Institute, Portland, Oregon, United States
| | - Edward N. Pugh
- University of California Davis, UC Davis Eyepod, Department of Cell Biology and Human Anatomy, Davis, California, United States
| | - Robert J. Zawadzki
- University of California Davis, UC Davis Eyepod, Department of Cell Biology and Human Anatomy, Davis, California, United States
- University of California Davis, UC Davis Eye Center, Department of Ophthalmology and Vision Science, Sacramento, California, United States
- Address all correspondence to Robert J. Zawadzki, E-mail:
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Reiter GS, Told R, Schlanitz FG, Bogunovic H, Baumann L, Sacu S, Schmidt-Erfurth U, Pollreisz A. Impact of Drusen Volume on Quantitative Fundus Autofluorescence in Early and Intermediate Age-Related Macular Degeneration. ACTA ACUST UNITED AC 2019; 60:1937-1942. [DOI: 10.1167/iovs.19-26566] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Gregor Sebastian Reiter
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Reinhard Told
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Ferdinand Georg Schlanitz
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Hrvoje Bogunovic
- Christian Doppler Laboratory for Ophthalmic Image Analysis, Vienna Reading Center, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Lukas Baumann
- Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Stefan Sacu
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Ursula Schmidt-Erfurth
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Ophthalmic Image Analysis, Vienna Reading Center, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Andreas Pollreisz
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
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46
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Smith D, Starborg T. Serial block face scanning electron microscopy in cell biology: Applications and technology. Tissue Cell 2019; 57:111-122. [DOI: 10.1016/j.tice.2018.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/22/2018] [Accepted: 08/26/2018] [Indexed: 10/28/2022]
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Grieve K, Gofas-Salas E, Ferguson RD, Sahel JA, Paques M, Rossi EA. In vivo near-infrared autofluorescence imaging of retinal pigment epithelial cells with 757 nm excitation. BIOMEDICAL OPTICS EXPRESS 2018; 9:5946-5961. [PMID: 31065405 PMCID: PMC6490976 DOI: 10.1364/boe.9.005946] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 05/06/2023]
Abstract
We demonstrate near-infrared autofluorescence (NIRAF) imaging of retinal pigment epithelial (RPE) cells in vivo in healthy volunteers and patients using a 757 nm excitation source in adaptive optics scanning laser ophthalmoscopy (AOSLO). NIRAF excited at 757 nm and collected in an emission band from 778 to 810 nm produced a robust NIRAF signal, presumably arising from melanin, and revealed the typical hexagonal mosaic of RPE cells at most eccentricities imaged within the macula of normal eyes. Several patterns of altered NIRAF structure were seen in patients, including disruption of the NIRAF over a drusen, diffuse hyper NIRAF signal with loss of individual cell delineation in a case of non-neovascular age-related macular degeneration (AMD), and increased visibility of the RPE mosaic under an area showing loss of photoreceptors. In some participants, a superposed cone mosaic was clearly visible in the fluorescence channel at eccentricities between 2 and 6° from the fovea. This was reproducible in these participants and existed despite the use of emission filters with an optical attenuation density of 12 at the excitation wavelength, minimizing the possibility that this was due to bleed through of the excitation light. This cone signal may be a consequence of cone waveguiding on either the ingoing excitation light and/or the outgoing NIRAF emitted by fluorophores within the RPE and/or choroid and warrants further investigation. NIRAF imaging at 757 nm offers efficient signal excitation and detection, revealing structural alterations in retinal disease with good contrast and shows promise as a tool for monitoring future therapies at the level of single RPE cells.
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Affiliation(s)
- Kate Grieve
- Vision Institute and Quinze Vingts National Ophthalmology Hospital, PARIS group, 28 rue de Charenton, 75712, Paris, France
| | - Elena Gofas-Salas
- Vision Institute and Quinze Vingts National Ophthalmology Hospital, PARIS group, 28 rue de Charenton, 75712, Paris, France
- DOTA, ONERA, Université Paris Saclay F-91123 Palaisea, France
| | | | - José Alain Sahel
- Vision Institute and Quinze Vingts National Ophthalmology Hospital, PARIS group, 28 rue de Charenton, 75712, Paris, France
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Michel Paques
- Vision Institute and Quinze Vingts National Ophthalmology Hospital, PARIS group, 28 rue de Charenton, 75712, Paris, France
| | - Ethan A. Rossi
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
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48
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Adaptive optics ophthalmoscopy: Application to age-related macular degeneration and vascular diseases. Prog Retin Eye Res 2018; 66:1-16. [DOI: 10.1016/j.preteyeres.2018.07.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 07/12/2018] [Accepted: 07/12/2018] [Indexed: 12/11/2022]
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49
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Moreno-García A, Kun A, Calero O, Medina M, Calero M. An Overview of the Role of Lipofuscin in Age-Related Neurodegeneration. Front Neurosci 2018; 12:464. [PMID: 30026686 PMCID: PMC6041410 DOI: 10.3389/fnins.2018.00464] [Citation(s) in RCA: 211] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/18/2018] [Indexed: 12/21/2022] Open
Abstract
Despite aging being by far the greatest risk factor for highly prevalent neurodegenerative disorders, the molecular underpinnings of age-related brain changes are still not well understood, particularly the transition from normal healthy brain aging to neuropathological aging. Aging is an extremely complex, multifactorial process involving the simultaneous interplay of several processes operating at many levels of the functional organization. The buildup of potentially toxic protein aggregates and their spreading through various brain regions has been identified as a major contributor to these pathologies. One of the most striking morphologic changes in neurons during normal aging is the accumulation of lipofuscin (LF) aggregates, as well as, neuromelanin pigments. LF is an autofluorescent lipopigment formed by lipids, metals and misfolded proteins, which is especially abundant in nerve cells, cardiac muscle cells and skin. Within the Central Nervous System (CNS), LF accumulates as aggregates, delineating a specific senescence pattern in both physiological and pathological states, altering neuronal cytoskeleton and cellular trafficking and metabolism, and being associated with neuronal loss, and glial proliferation and activation. Traditionally, the accumulation of LF in the CNS has been considered a secondary consequence of the aging process, being a mere bystander of the pathological buildup associated with different neurodegenerative disorders. Here, we discuss recent evidence suggesting the possibility that LF aggregates may have an active role in neurodegeneration. We argue that LF is a relevant effector of aging that represents a risk factor or driver for neurodegenerative disorders.
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Affiliation(s)
| | - Alejandra Kun
- Biochemistry Section, Science School, Universidad de la República, Montevideo, Uruguay
- Protein and Nucleic Acids Department, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Olga Calero
- Chronic Disease Programme-CROSADIS, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - Miguel Medina
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
- Alzheimer Disease Research Unit, CIEN Foundation, Queen Sofia Foundation Alzheimer Center, Madrid, Spain
| | - Miguel Calero
- Chronic Disease Programme-CROSADIS, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
- Alzheimer Disease Research Unit, CIEN Foundation, Queen Sofia Foundation Alzheimer Center, Madrid, Spain
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50
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Yang F, Liu X, Zhao Y, Zhang Y, Wang P, Robinson I, Chen B. Investigation of Three-Dimensional Microstructure of Tricalcium Silicate (C₃S) by Electron Microscopy. MATERIALS 2018; 11:ma11071110. [PMID: 29966230 PMCID: PMC6073500 DOI: 10.3390/ma11071110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/18/2018] [Accepted: 06/27/2018] [Indexed: 11/16/2022]
Abstract
A serial block-face scanning electron microscopy (SBFSEM) system, composed of a scanning electron microscope (SEM) and an ultra-microtome installed within the SEM vacuum chamber, has been used to characterize the three-dimensional (3D) microstructure of tricalcium silicate (C3S) grains embedded in epoxy resin. A selection of C3S grains were segmented and rendered with 3D-image processing software, which allowed the C3S grains to be clearly visualized and enabled statistically quantitative analysis. The results show that about 5% of the C3S grains have volumes larger than 1 μm3 and the average volume of the grains is 25 μm3. Pores can also be clearly seen in the biggest C3S grain, the volume of which is 3.6 × 104 μm3, and the mean volume and total volume of all the pores within this grain are 4.8 μm3 and 3.0 × 103 μm3, respectively. The reported work provides a new approach for the characterization of the 3D spatial structure of raw C3S materials, and the resulting 3D structure of the raw C3S is important for further systematic research on the relationships between the spatial microstructure and the hydration kinetics of C3S and other cement minerals.
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Affiliation(s)
- Fei Yang
- School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
| | - Xianping Liu
- School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
- Key Laboratory of Advanced Civil Engineering Materials (Tongji University), Ministry of Education, Shanghai 201804, China.
| | - Yongjuan Zhao
- School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
| | - Yongming Zhang
- School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
| | - Peiming Wang
- School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
- Key Laboratory of Advanced Civil Engineering Materials (Tongji University), Ministry of Education, Shanghai 201804, China.
| | - Ian Robinson
- School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
- Division of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Bo Chen
- School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
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