1
|
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.
Collapse
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
| |
Collapse
|
2
|
Kar D, Singireddy R, Kim YJ, Packer O, Schalek R, Cao D, Sloan KR, Pollreisz A, Dacey DM, Curcio CA. Unusual morphology of foveal Müller glia in an adult human born pre-term. Front Cell Neurosci 2024; 18:1409405. [PMID: 38994326 PMCID: PMC11236602 DOI: 10.3389/fncel.2024.1409405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Accepted: 06/06/2024] [Indexed: 07/13/2024] Open
Abstract
The fovea of the human retina, a specialization for acute and color vision, features a high concentration of cone photoreceptors. A pit on the inner retinal aspect is created by the centrifugal migration of post-receptoral neurons. Foveal cells are specified early in fetal life, but the fovea reaches its final configuration postnatally. Pre-term birth retards migration resulting in a small pit, a small avascular zone, and nearly continuous inner retinal layers. To explore the involvement of Müller glia, we used serial-section electron microscopic reconstructions to examine the morphology and neural contacts of Müller glia contacting a single foveal cone in a 28-year-old male organ donor born at 28 weeks of gestation. A small non-descript foveal avascular zone contained massed glial processes that included a novel class of 'inner' Müller glia. Similar to classic 'outer' Müller glia that span the retina, inner Müller glia have bodies in the inner nuclear layer (INL). These cells are densely packed with intermediate filaments and insert processes between neurons. Unlike 'outer' Müller glia, 'inner' Müller glia do not reach the external limiting membrane but instead terminate at the outer plexiform layer. One completely reconstructed inner cell ensheathed cone pedicles and a cone-driven circuit of midget bipolar and ganglion cells. Inner Müller glia outnumber foveal cones by 1.8-fold in the outer nuclear layer (221,448 vs. 123,026 cells/mm2). Cell bodies of inner Müller glia outnumber those of outer Müller glia by 1.7-fold in the INL (41,872 vs. 24,631 cells/ mm2). Müller glia account for 95 and 80% of the volume of the foveal floor and Henle fiber layer, respectively. Determining whether inner cells are anomalies solely resulting from retarded lateral migration of inner retinal neurons in pre-term birth requires further research.
Collapse
Affiliation(s)
- Deepayan Kar
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ramya Singireddy
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Yeon Jin Kim
- Department of Biological Structure, University of Washington, Seattle, WA, United States
| | - Orin Packer
- Department of Biological Structure, University of Washington, Seattle, WA, United States
| | - Richard Schalek
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, United States
| | - Dongfeng Cao
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kenneth R Sloan
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Dennis M Dacey
- Department of Biological Structure, University of Washington, Seattle, WA, United States
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| |
Collapse
|
3
|
Neto MV, De Rossi G, Berkowitz BA, Seabra MC, Luthert PJ, Futter CE, Burgoyne T. Daily Light Onset and Plasma Membrane Tethers Regulate Mitochondria Redistribution within the Retinal Pigment Epithelium. Cells 2024; 13:1100. [PMID: 38994953 PMCID: PMC11240580 DOI: 10.3390/cells13131100] [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: 05/03/2024] [Revised: 06/15/2024] [Accepted: 06/17/2024] [Indexed: 07/13/2024] Open
Abstract
The retinal pigment epithelium (RPE) is an essential component of the retina that plays multiple roles required to support visual function. These include light onset- and circadian rhythm-dependent tasks, such as daily phagocytosis of photoreceptor outer segments. Mitochondria provide energy to the highly specialized and energy-dependent RPE. In this study, we examined the positioning of mitochondria and how this is influenced by the onset of light. We identified a population of mitochondria that are tethered to the basal plasma membrane pre- and post-light onset. Following light onset, mitochondria redistributed apically and interacted with melanosomes and phagosomes. In a choroideremia mouse model that has regions of the RPE with disrupted or lost infolding of the plasma membrane, the positionings of only the non-tethered mitochondria were affected. This provides evidence that the tethering of mitochondria to the plasma membrane plays an important role that is maintained under these disease conditions. Our work shows that there are subpopulations of RPE mitochondria based on their positioning after light onset. It is likely they play distinct roles in the RPE that are needed to fulfil the changing cellular demands throughout the day.
Collapse
Affiliation(s)
- Matilde V Neto
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Giulia De Rossi
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Bruce A Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48202, USA
| | - Miguel C Seabra
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Philip J Luthert
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Clare E Futter
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Thomas Burgoyne
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| |
Collapse
|
4
|
Geng Q, Keya JJ, Hotta T, Verhey KJ. The kinesin-3 KIF1C undergoes liquid-liquid phase separation for accumulation of specific transcripts at the cell periphery. EMBO J 2024:10.1038/s44318-024-00147-9. [PMID: 38898313 DOI: 10.1038/s44318-024-00147-9] [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: 03/19/2024] [Revised: 04/30/2024] [Accepted: 05/17/2024] [Indexed: 06/21/2024] Open
Abstract
In cells, mRNAs are transported to and positioned at subcellular areas to locally regulate protein production. Recent studies have identified the kinesin-3 family member motor protein KIF1C as an RNA transporter. However, it is not clear how KIF1C interacts with RNA molecules. Here, we show that the KIF1C C-terminal tail domain contains an intrinsically disordered region (IDR) that drives liquid-liquid phase separation (LLPS). KIF1C forms dynamic puncta in cells that display physical properties of liquid condensates and incorporate RNA molecules in a sequence-selective manner. Endogenous KIF1C forms condensates in cellular protrusions, where mRNAs are enriched in an IDR-dependent manner. Purified KIF1C tail constructs undergo LLPS in vitro at near-endogenous nM concentrations and in the absence of crowding agents and can directly recruit RNA molecules. Overall, our work uncovers an intrinsic correlation between the LLPS activity of KIF1C and its role in mRNA positioning. In addition, the LLPS activity of KIF1C's tail represents a new mode of motor-cargo interaction that extends our current understanding of cytoskeletal motor proteins.
Collapse
Affiliation(s)
- Qi Geng
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jakia Jannat Keya
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Takashi Hotta
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.
| |
Collapse
|
5
|
Prenner V, Reiter GS, Fuchs P, Birner K, Frank S, Coulibaly L, Gumpinger M, Bogunovic H, Schmidt-Erfurth U. Advancing the visibility of outer retinal integrity in neovascular age-related macular degeneration with high-resolution OCT. CANADIAN JOURNAL OF OPHTHALMOLOGY 2024:S0008-4182(24)00157-1. [PMID: 38901467 DOI: 10.1016/j.jcjo.2024.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/22/2024] [Accepted: 05/20/2024] [Indexed: 06/22/2024]
Abstract
OBJECTIVE To compare the visibility and accessibility of the outer retina in neovascular age-related macular degeneration (nAMD) between 2 OCT devices. METHODS In this prospective, cross-sectional exploratory study, differences in thickness and loss of individual outer retinal layers in eyes with nAMD and in age-matched healthy eyes between a next-level High-Res OCT device and the conventional SPECTRALIS OCT (both Heidelberg Engineering GmbH, Heidelberg, Germany) were analyzed. Eyes with nAMD and at least 250 nL of retinal fluid, quantified by an approved deep-learning algorithm (Fluid Monitor, RetInSight, Vienna, Austria), fulfilled the inclusion criteria. The outer retinal layers were segmented using automated layer segmentation and were corrected manually. Layer loss and thickness were compared between both devices using a linear mixed-effects model and a paired t test. RESULTS Nineteen eyes of 17 patients with active nAMD and 17 healthy eyes were included. For nAMD eyes, the thickness of the retinal pigment epithelium (RPE) differed significantly between the devices (25.42 μm [95% CI, 14.24-36.61] and 27.31 μm [95% CI, 16.12-38.50] for high-resolution OCT and conventional OCT, respectively; p = 0.033). Furthermore, a significant difference was found in the mean relative external limiting membrane loss (p = 0.021). However, the thickness of photoreceptors, RPE integrity loss, and photoreceptor integrity loss did not differ significantly between devices in the central 3 mm. In healthy eyes, a significant difference in both RPE and photoreceptor thickness between devices was shown (p < 0.001). CONCLUSION Central RPE thickness was significantly thinner on high-resolution OCT compared with conventional OCT images explained by superior optical separation of the RPE and Bruch's membrane.
Collapse
Affiliation(s)
- Veronika Prenner
- Laboratory for Ophthalmic Image Analysis, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Gregor Sebastian Reiter
- Laboratory for Ophthalmic Image Analysis, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Philipp Fuchs
- Laboratory for Ophthalmic Image Analysis, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Klaudia Birner
- Laboratory for Ophthalmic Image Analysis, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Sophie Frank
- Laboratory for Ophthalmic Image Analysis, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Leonard Coulibaly
- Laboratory for Ophthalmic Image Analysis, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Markus Gumpinger
- Christian Doppler Laboratory for Artificial Intelligence in Retina, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Hrvoje Bogunovic
- Laboratory for Ophthalmic Image Analysis, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Artificial Intelligence in Retina, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Ursula Schmidt-Erfurth
- Laboratory for Ophthalmic Image Analysis, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria.
| |
Collapse
|
6
|
Kunala K, Tang JAH, Parkins K, Hunter JJ. Multispectral label-free in vivo cellular imaging of human retinal pigment epithelium using adaptive optics fluorescence lifetime ophthalmoscopy improves feasibility for low emission analysis and increases sensitivity for detecting changes with age and eccentricity. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:S22707. [PMID: 38962492 PMCID: PMC11221116 DOI: 10.1117/1.jbo.29.s2.s22707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 07/05/2024]
Abstract
Significance Adaptive optics fluorescence lifetime ophthalmoscopy (AOFLIO) provides a label-free approach to observe functional and molecular changes at cellular scale in vivo. Adding multispectral capabilities improves interpretation of lifetime fluctuations due to individual fluorophores in the retinal pigment epithelium (RPE). Aim To quantify the cellular-scale changes in autofluorescence with age and eccentricity due to variations in lipofuscin, melanin, and melanolipofuscin in RPE using multispectral AOFLIO. Approach AOFLIO was performed on six subjects at seven eccentricities. Four imaging channels (λ ex / λ em ) were used: 473/SSC, 473/LSC, 532/LSC, and 765/NIR. Cells were segmented and the timing signals of each pixel in a cell were combined into a single histogram, which were then used to compute the lifetime and phasor parameters. An ANOVA was performed to investigate eccentricity and spectral effects on each parameter. Results A repeatability analysis revealed < 11.8 % change in lifetime parameters in repeat visits for 532/LSC. The 765/NIR and 532/LSC had eccentricity and age effects similar to previous reports. The 473/LSC had a change in eccentricity with mean lifetime and a phasor component. Both the 473/LSC and 473/SSC had changes in eccentricity in the short lifetime component and its relative contribution. The 473/SSC had no trend in eccentricity in phasor. The comparison across the four channels showed differences in lifetime and phasor parameters. Conclusions Multispectral AOFLIO can provide a more comprehensive picture of changes with age and eccentricity. These results indicate that cell segmentation has the potential to allow investigations in low-photon scenarios such as in older or diseased subjects with the co-capture of an NIR channel (such as 765/NIR) with the desired spectral channel. This work represents the first multispectral, cellular-scale fluorescence lifetime comparison in vivo in the human RPE and may be a useful method for tracking diseases.
Collapse
Affiliation(s)
- Karteek Kunala
- Stanford University, Byers Eye Institute, Palo Alto, California, United States
| | - Janet A. H. Tang
- University of Rochester, Center for Visual Science, Rochester, New York, United States
- University of Rochester, The Institute of Optics, Rochester, New York, United States
| | - Keith Parkins
- University of Rochester, Center for Visual Science, Rochester, New York, United States
| | - Jennifer J. Hunter
- University of Rochester, Center for Visual Science, Rochester, New York, United States
- University of Rochester, The Institute of Optics, Rochester, New York, United States
- University of Waterloo, School of Optometry and Vision Science, Waterloo, Ontario, Canada
| |
Collapse
|
7
|
Hultgren NW, Zhou T, Williams DS. Machine learning-based 3D segmentation of mitochondria in polarized epithelial cells. Mitochondrion 2024; 76:101882. [PMID: 38599302 DOI: 10.1016/j.mito.2024.101882] [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: 04/25/2023] [Revised: 03/18/2024] [Accepted: 04/07/2024] [Indexed: 04/12/2024]
Abstract
Mitochondria are dynamic organelles that alter their morphological characteristics in response to functional needs. Therefore, mitochondrial morphology is an important indicator of mitochondrial function and cellular health. Reliable segmentation of mitochondrial networks in microscopy images is a crucial initial step for further quantitative evaluation of their morphology. However, 3D mitochondrial segmentation, especially in cells with complex network morphology, such as in highly polarized cells, remains challenging. To improve the quality of 3D segmentation of mitochondria in super-resolution microscopy images, we took a machine learning approach, using 3D Trainable Weka, an ImageJ plugin. We demonstrated that, compared with other commonly used methods, our approach segmented mitochondrial networks effectively, with improved accuracy in different polarized epithelial cell models, including differentiated human retinal pigment epithelial (RPE) cells. Furthermore, using several tools for quantitative analysis following segmentation, we revealed mitochondrial fragmentation in bafilomycin-treated RPE cells.
Collapse
Affiliation(s)
- Nan W Hultgren
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA 90095, USA.
| | - Tianli Zhou
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA 90095, USA
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA 90095, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA; Brain Research Institute, University of California, Los Angeles, CA 90095, USA.
| |
Collapse
|
8
|
Shahhossein-Dastjerdi S, Koina ME, Fatseas G, Arfuso F, Chan-Ling T. Autophagy and Exocytosis of Lipofuscin Into the Basolateral Extracellular Space of Human Retinal Pigment Epithelium From Fetal Development to Adolescence. Invest Ophthalmol Vis Sci 2024; 65:32. [PMID: 38648041 PMCID: PMC11044829 DOI: 10.1167/iovs.65.4.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 03/06/2024] [Indexed: 04/25/2024] Open
Abstract
Purpose To undertake the first ultrastructural characterization of human retinal pigment epithelial (RPE) differentiation from fetal development to adolescence. Methods Ten fetal eyes and three eyes aged six, nine, and 17 years were examined in the temporal retina adjacent to the optic nerve head by transmission electron microscopy. The area, number, and distribution of RPE organelles were quantified and interpreted within the context of adjacent photoreceptors, Bruch's membrane, and choriocapillaris maturation. Results Between eight to 12 weeks' gestation (WG), pseudostratified columnar epithelia with apical tight junctions differentiate to a simple cuboidal epithelium with random distribution of melanosomes and mitochondria. Between 12 to 26 WG, cells enlarge and show long apical microvilli and apicolateral junctional complexes. Coinciding with eye opening at 26 WG, melanosomes migrate apically whereas mitochondria distribute to perinuclear regions, with the first appearance of phagosomes, complex granules, and basolateral extracellular space (BES) formation. Significantly, autophagy and heterophagy, as evidenced by organelle recycling, and the gold standard of ultrastructural evidence for autophagy of double-membrane autophagosomes and mitophagosomes were evident from 32 WG, followed by basal infoldings of RPE cell membrane at 36 WG. Lipofuscin formation and deposition into the BES evident at six years increased at 17 years. Conclusions We provide compelling ultrastructural evidence that heterophagy and autophagy begins in the third trimester of human fetal development and that deposition of cellular byproducts into the extracellular space of RPE takes place via exocytosis. Transplanted RPE cells must also demonstrate the capacity to subserve autophagic and heterophagic functions for effective disease mitigation.
Collapse
Affiliation(s)
- Saeed Shahhossein-Dastjerdi
- Bosch Institute, The University of Sydney, Sydney, Australia
- Now at Cell, Tissue & Organ Bank, Forensic Medicine Research Centre, Tehran, Iran
| | - Mark E. Koina
- Department of Anatomical Pathology, ACT Pathology, The Canberra Hospital, Canberra, Australia
| | - George Fatseas
- Bosch Institute, The University of Sydney, Sydney, Australia
| | - Frank Arfuso
- School of Human Sciences, The University of Western Australia, Crawley, Australia
| | | |
Collapse
|
9
|
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.
Collapse
Affiliation(s)
| | - Mikhail Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia;
| |
Collapse
|
10
|
Heath Jeffery RC, Lo J, Thompson JA, Lamey TM, McLaren TL, De Roach JN, Ayton LN, Vincent AL, Sharma A, Chen FK. Analysis of the Outer Retinal Bands in ABCA4 and PRPH2-Associated Retinopathy using OCT. Ophthalmol Retina 2024; 8:174-183. [PMID: 37209970 DOI: 10.1016/j.oret.2023.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/09/2023] [Accepted: 05/12/2023] [Indexed: 05/22/2023]
Abstract
PURPOSE To evaluate the outer retinal bands using OCT in ABCA4- and PRPH2-associated retinopathy and develop a novel imaging biomarker to differentiate between these 2 genotypes. DESIGN Multicenter case-control study. PARTICIPANTS Patients with a clinical and genetic diagnosis of ABCA4- or PRPH2-associated retinopathy and an age-matched control group. METHODS Macular OCT was used to measure the thickness of the outer retinal bands 2 and 4 by 2 independent examiners at 4 retinal loci. MAIN OUTCOME MEASURES Outcome measures included the thicknesses of band 2, band 4, and the band 2/band 4 ratio. Linear mixed modeling was used to make comparisons across the 3 groups. Receiver operating characteristic (ROC) analysis determined the optimal cutoff for the band 2/band 4 ratio to distinguish PRPH2- from ABCA4-associated retinopathy. RESULTS We included 45 patients with ABCA4 variants, 45 patients with PRPH2 variants, and 45 healthy controls. Band 2 was significantly thicker in patients with PRPH2 compared with ABCA4 (21.4 vs. 15.9 μm, P < 0.001) variants, whereas band 4 was thicker in patients with ABCA4 variants than those with PRPH2 variants (27.5 vs. 21.7 μm, P < 0.001). Similarly, the band 2/band 4 ratio was significantly different (1.0 vs. 0.6 for PRPH2 vs. ABCA4, P < 0.001). The area under the ROC curve was 0.87 for either band 2 (> 18.58 μm) or band 4 (< 26.17 μm) alone and 0.99 (95% confidence interval: 0.97-0.99) for the band 2/band 4 ratio with a cutoff threshold of 0.79, providing 100% specificity. CONCLUSIONS We report an altered outer retinal band profile whereby the band 2/band 4 ratio was able to discriminate between PRPH2- and ABCA4-associated retinopathy. This may have future clinic utility in predicting the genotype and provide further insight into the anatomic correlate of band 2. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
Collapse
Affiliation(s)
- Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
| | - Johnny Lo
- School of Science, Edith Cowan University, Perth, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Terri L McLaren
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - John N De Roach
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Lauren N Ayton
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Andrea L Vincent
- Department of Ophthalmology, FMHS, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Abhishek Sharma
- Ophthalmology Department, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia.
| |
Collapse
|
11
|
Fasih-Ahmad S, Wang Z, Mishra Z, Vatanatham C, Clark ME, Swain TA, Curcio CA, Owsley C, Sadda SR, Hu ZJ. Potential Structural Biomarkers in 3D Images Validated by the First Functional Biomarker for Early Age-Related Macular Degeneration - ALSTAR2 Baseline. Invest Ophthalmol Vis Sci 2024; 65:1. [PMID: 38300559 PMCID: PMC10846345 DOI: 10.1167/iovs.65.2.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024] Open
Abstract
Purpose Lack of valid end points impedes developing therapeutic strategies for early age-related macular degeneration (AMD). Delayed rod-mediated dark adaptation (RMDA) is the first functional biomarker for incident early AMD. The relationship between RMDA and the status of outer retinal bands on optical coherence tomography (OCT) have not been well defined. This study aims to characterize these relationships in early and intermediate AMD. Methods Baseline data from 476 participants was assessed including eyes with early AMD (n = 138), intermediate AMD (n = 101), and normal aging (n = 237). Participants underwent volume OCT imaging of the macula and rod intercept time (RIT) was measured. The ellipsoid zone (EZ) and interdigitation zone (IZ) on all OCT B-scans of the volumes were segmented. The area of detectable EZ and IZ, and mean thickness of IZ within the Early Treatment Diabetic Retinopathy Study (ETDRS) grid were computed and associations with RIT were assessed by Spearman's correlation coefficient and age adjusted. Results Delayed RMDA (longer RIT) was most strongly associated with less preserved IZ area (r = -0.591; P < 0.001), followed by decreased IZ thickness (r = -0.434; P < 0.001), and EZ area (r = -0.334; P < 0.001). This correlation between RIT and IZ integrity was not apparent when considering normal eyes alone within 1.5 mm of the fovea. Conclusions RMDA is correlated with the status of outer retinal bands in early and intermediate AMD eyes, particularly, the status of the IZ. This correlation is consistent with a previous analysis of only foveal B-scans and is biologically plausible given that retinoid availability, involving transfer at the interface attributed to the IZ, is rate-limiting for RMDA.
Collapse
Affiliation(s)
| | - Ziyuan Wang
- Doheny Eye Institute, Pasadena, California, United States
| | - Zubin Mishra
- Doheny Eye Institute, Pasadena, California, United States
| | | | - Mark E Clark
- Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Thomas A Swain
- Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Christine A Curcio
- Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Cynthia Owsley
- Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | | | | |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Berlin A, Messinger JD, Ramtohul P, Balaratnasingam C, Mendis R, Ferrara D, Freund KB, Curcio CA. INFLAMMATORY CELL ACTIVITY IN TREATED NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: A Histologic Case Study. Retina 2023; 43:1904-1913. [PMID: 37871271 PMCID: PMC10801910 DOI: 10.1097/iae.0000000000003881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
BACKGROUND Imaging indicators of macular neovascularization risk can help determine patient eligibility for new treatments for geographic atrophy secondary to age-related macular degeneration. Because type 1 macular neovascularization includes inflammation, we assessed by histology the distribution of cells with inflammatory potential in two fellow eyes with age-related macular degeneration. METHODS Two eyes of a White woman in her 90's with type 3 macular neovascularization treated with antivascular endothelial growth factor were prepared for high-resolution histology. Eye-tracked spectral domain optical coherence tomography applied to the preserved donor eyes linked in vivo imaging to histology. Cells were enumerated in the intraretinal, subretinal, and subretinal retinal pigment epithelium (RPE)-basal lamina compartments on 199 glass slides. Cells with numerous organelles were considered to RPE-derived; cells with sparse RPE organelles were considered non-RPE phagocytes. RESULTS Both eyes had soft drusen and abundant subretinal drusenoid deposit. In the retina and subretinal space, RPE-derived cells, including hyperreflective foci, were common (n = 125 and 73, respectively). Non-RPE phagocytes were infrequent (n = 5 in both). Over drusen, RPE morphology transitioned smoothly from the age-normal layer toward the top, suggesting transdifferentiation. The sub-RPE-basal lamina space had RPE-derived cells (n = 87) and non-RPE phagocytes (n = 49), including macrophages and giant cells. CONCLUSION Numerous sub-RPE-basal lamina cells of several types are consistent with the documented presence of proinflammatory lipids in drusen and aged Bruch's membrane. The relatively compartmentalized abundance of infiltrating cells suggests that drusen contents are more inflammatory than subretinal drusenoid deposit, perhaps reflecting their environments. Ectopic RPE occurs frequently. Some manifest as hyperreflective foci. More cells may be visible as optical coherence tomography technologies evolve.
Collapse
Affiliation(s)
- Andreas Berlin
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
- Department of Ophthalmology, University Hospital Würzburg, Würzburg, Germany
| | - Jeffrey D Messinger
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| | | | - Chandrakumar Balaratnasingam
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Department of Ophthalmology, Sir Charles Gairdner Hospital, Western Australia, Australia
| | | | | | - K. Bailey Freund
- Vitreous Retina Macula Consultants of 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, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham AL, USA
| |
Collapse
|
16
|
Geng Q, Keya JJ, Hotta T, Verhey KJ. KIF1C, an RNA transporting kinesin-3, undergoes liquid-liquid phase separation through its C-terminal disordered domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563538. [PMID: 37961614 PMCID: PMC10634753 DOI: 10.1101/2023.10.23.563538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The spatial distribution of mRNA is critical for local control of protein production. Recent studies have identified the kinesin-3 family member KIF1C as an RNA transporter. However, it is not clear how KIF1C interacts with RNA molecules. Here, we show that KIF1C's C-terminal tail domain is an intrinsically disordered region (IDR) containing a prion-like domain (PLD) that is unique compared to the C-terminal tails of other kinesin family members. In cells, KIF1C constructs undergo reversible formation of dynamic puncta that display physical properties of liquid condensates and incorporate RNA molecules in a sequence-selective manner. The IDR is necessary and sufficient for driving liquid-liquid phase separation (LLPS) but the condensate properties can be modulated by adjacent coiled-coil segments. The purified KIF1C IDR domain undergoes LLPS in vitro at near-endogenous nM concentrations in a salt-dependent manner. Deletion of the IDR abolished the ability of KIF1C to undergo LLPS and disrupted the distribution of mRNA cargoes to the cell periphery. Our work thus uncovers an intrinsic correlation between the LLPS activity of KIF1C and its role as an RNA transporter. In addition, as the first kinesin motor reported to undergo LLPS, our work reveals a previously uncharacterized mode of motor-cargo interaction that extends our understanding of the behavior of cytoskeletal motor proteins.
Collapse
Affiliation(s)
- Qi Geng
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jakia Jannat Keya
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Takashi Hotta
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| |
Collapse
|
17
|
Dontsov AE, Yakovleva MA, Vasin AA, Gulin AA, Aybush AV, Nadtochenko VA, Ostrovsky MA. Understanding the Mechanism of Light-Induced Age-Related Decrease in Melanin Concentration in Retinal Pigment Epithelium Cells. Int J Mol Sci 2023; 24:13099. [PMID: 37685907 PMCID: PMC10487480 DOI: 10.3390/ijms241713099] [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: 07/23/2023] [Revised: 08/13/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
It is known that during the process of aging, there is a significant decrease in the number of melanosomes in the retinal pigment epithelium (RPE) cells in the human eye. Melanosomes act as screening pigments in RPE cells and are fundamentally important for protection against the free radicals generated by light. A loss or change in the quality of melanin in melanosomes can lead to the development of senile pathologies and aggravation in the development of various retinal diseases. We have previously shown that the interaction between melanin melanosomes and superoxide radicals results in oxidative degradation with the formation of water-soluble fluorescent products. In the present study, we show, using fluorescence analysis, HPLC, and mass spectrometry, that visible light irradiation on melanolipofuscin granules isolated from RPE cells in the human eye results in the formation of water-soluble fluorescent products from oxidative degradation of melanin, which was in contrast to lipofuscin granules and melanosomes irradiation. The formation of these products occurs as a result of the oxidative degradation of melanin by superoxide radicals, which are generated by the lipofuscin part of the melanolipofuscin granule. We identified these products both in the composition of melanolipofuscin granules irradiated with visible light and in the composition of melanosomes that were not irradiated but were, instead, oxidized by superoxide radicals. In the melanolipofuscin granules irradiated by visible light, ions that could be associated with melanin oxidative degradation products were identified by applying the principal component analysis of the time-of-flight secondary ion mass spectrometry (ToF-SIMS) data. Degradation of the intact melanosomes by visible light is also possible; however, this requires significantly higher irradiation intensities than for melanolipofuscin granules. It is concluded that the decrease in the concentration of melanin in RPE cells in the human eye with age is due to its oxidative degradation by reactive oxygen species generated by lipofuscin, as part of the melanolipofuscin granules, under the action of light.
Collapse
Affiliation(s)
- Alexander E. Dontsov
- Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, 119334 Moscow, Russia; (M.A.Y.); (M.A.O.)
| | - Marina A. Yakovleva
- Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, 119334 Moscow, Russia; (M.A.Y.); (M.A.O.)
| | - Alexander A. Vasin
- Federal Research Center of Chemical Physics, Russian Academy of Sciences, N.N. Semenov RAS, 119991 Moscow, Russia; (A.A.V.); (A.A.G.); (A.V.A.); (V.A.N.)
| | - Alexander A. Gulin
- Federal Research Center of Chemical Physics, Russian Academy of Sciences, N.N. Semenov RAS, 119991 Moscow, Russia; (A.A.V.); (A.A.G.); (A.V.A.); (V.A.N.)
| | - Arseny V. Aybush
- Federal Research Center of Chemical Physics, Russian Academy of Sciences, N.N. Semenov RAS, 119991 Moscow, Russia; (A.A.V.); (A.A.G.); (A.V.A.); (V.A.N.)
| | - Viktor A. Nadtochenko
- Federal Research Center of Chemical Physics, Russian Academy of Sciences, N.N. Semenov RAS, 119991 Moscow, Russia; (A.A.V.); (A.A.G.); (A.V.A.); (V.A.N.)
| | - Mikhail A. Ostrovsky
- Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, 119334 Moscow, Russia; (M.A.Y.); (M.A.O.)
| |
Collapse
|
18
|
Low SWY, Lim RR, Grant DG, Patterson S, Chaurasia SS. New Insights into RPE-Photoreceptor Complex Ultrastructure using Focused Ion Beam-Scanning Election Microscopy (FIB-SEM). RESEARCH SQUARE 2023:rs.3.rs-3200741. [PMID: 37609321 PMCID: PMC10441459 DOI: 10.21203/rs.3.rs-3200741/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Photoreceptors in the retina are specialized neuronal cells that perceive light and play a central role in the visual system. Damage to photoreceptors is a clinical feature often associated with various retinal degenerative disorders. The photoreceptor bed comprises a unique extracellular matrix (ECM) scaffold often described as the interphotoreceptor matrix (IPM) in the subretinal space, vital during retinal development and homeostasis. In this study, we used focused ion beam scanning electron microscopy (FIB-SEM) and transmission electron microscopy (TEM) to analyze the ultrastructural architecture of the retinal pigmented epithelium (RPE)-photoreceptor complex in mice. Additionally, we describe methods for retinal preparation in EM imaging. TEM images display ultrastructural retina layers, including Bruch's membrane and the interdigitation zone (IZ). The 3-dimensional reconstruction of the outer retina revealed individual photoreceptors, the connection between their inner and outer segment via the photoreceptor cilia, and photoreceptor interaction with the RPE ciliary processes. Our findings highlight the importance of FIB-SEM in deciphering the ultrastructural details of RPE-photoreceptor interactions in the IPM complex which are essential for the maintenance of retinal architecture.
Collapse
|
19
|
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.
Collapse
|
20
|
Simon R, Jentsch M, Karimimousivandi P, Cao D, Messinger JD, Meller D, Curcio CA, Hammer M. Prolonged Lifetimes of Histologic Autofluorescence in Ectopic Retinal Pigment Epithelium in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2022; 63:5. [PMID: 36469025 PMCID: PMC9730734 DOI: 10.1167/iovs.63.13.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose The purpose of this study was to investigate histologic autofluorescence lifetimes and spectra of retinal pigment epithelium (RPE) on the transition from normal aging to RPE activation and migration in age-related macular degeneration (AMD). Methods Autofluorescence lifetimes and spectra of 9 donor eyes were analyzed in cryosections by means of 2-photon excited fluorescence at 960 nm. Spectra were detected at 483 to 665 nm. Lifetimes were measured using time-correlated single photon counting in 2 spectral channels: 500 to 550 nm (short-wavelength spectral channel [SSC]) and 550 to 700 nm (long-wavelength spectral channel [LSC]). Fluorescence decays over time were approximated by a series of three exponential functions. The amplitude-weighted mean fluorescence lifetime was determined. Markers for retinoid activity (RPE65) and immune function (CD68) were immunolocalized in selected neighboring sections. Results We identified 9 RPE morphology phenotypes resulting in 399 regions of interest (ROIs) for spectral and 497 ROIs for lifetime measurements. RPE dysmorphia results in a shorter wavelength peak of spectral emission: normal aging versus RPE migrated into the retina (intraELM) = 601.7 (9.5) nm versus 581.6 (7.3) nm, P < 0.001, whereas autofluorescence lifetimes increase: normal aging versus intraELM: SSC 180 (44) picosecond (ps) versus 320 (86) ps, P < 0.001; and LSC 250 (55) ps versus 441 (76) ps, P < 0.001. Ectopic RPE within the neurosensory retina is strongly CD68 positive and RPE65 negative. Conclusions In the process of RPE degeneration, comprising different steps of dysmorphia and migration, lengthening of autofluorescence lifetimes and a hypsochromic shift of emission spectra can be observed. These autofluorescence changes might provide early biomarkers for AMD progression and contribute to our understanding of RPE-driven pathology.
Collapse
Affiliation(s)
- Rowena Simon
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Marius Jentsch
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | | | - Dongfeng Cao
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jeffrey D Messinger
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Daniel Meller
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Martin Hammer
- Department of Ophthalmology, University Hospital Jena, Jena, Germany.,Center for Medical Optics and Photonics, University of Jena, Jena, Germany
| |
Collapse
|
21
|
Tan LX, Li J, Germer CJ, Lakkaraju A. Analysis of mitochondrial dynamics and function in the retinal pigment epithelium by high-speed high-resolution live imaging. Front Cell Dev Biol 2022; 10:1044672. [PMID: 36393836 PMCID: PMC9651161 DOI: 10.3389/fcell.2022.1044672] [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: 09/14/2022] [Accepted: 10/19/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial dysfunction is strongly implicated in neurodegenerative diseases including age-related macular degeneration (AMD), which causes irreversible blindness in over 50 million older adults worldwide. A key site of insult in AMD is the retinal pigment epithelium (RPE), a monolayer of postmitotic polarized cells that performs essential functions for photoreceptor health and vision. Recent studies from our group and others have identified several features of mitochondrial dysfunction in AMD including mitochondrial fragmentation and bioenergetic defects. While these studies provide valuable insight at fixed points in time, high-resolution, high-speed live imaging is essential for following mitochondrial injury in real time and identifying disease mechanisms. Here, we demonstrate the advantages of live imaging to investigate RPE mitochondrial dynamics in cell-based and mouse models. We show that mitochondria in the RPE form extensive networks that are destroyed by fixation and discuss important live imaging considerations that can interfere with accurate evaluation of mitochondrial integrity such as RPE differentiation status and acquisition parameters. Our data demonstrate that RPE mitochondria show localized heterogeneities in membrane potential and ATP production that could reflect focal changes in metabolism and oxidative stress. Contacts between the mitochondria and organelles such as the ER and lysosomes mediate calcium flux and mitochondrial fission. Live imaging of mouse RPE flatmounts revealed a striking loss of mitochondrial integrity in albino mouse RPE compared to pigmented mice that could have significant functional consequences for cellular metabolism. Our studies lay a framework to guide experimental design and selection of model systems for evaluating mitochondrial health and function in the RPE.
Collapse
Affiliation(s)
- Li Xuan Tan
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, United States
| | - Jianlong Li
- Department of Cell and Tissue Biology, School of Dentistry, University of California, San Francisco, CA, United States
| | - Colin J. Germer
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, United States
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, United States
| | - Aparna Lakkaraju
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, United States
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, United States
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA, United States
| |
Collapse
|
22
|
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.
Collapse
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
Collapse
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
| |
Collapse
|
23
|
Berlin A, Clark ME, Swain TA, Fischer NA, McGwin G, Sloan KR, Owsley C, Curcio CA. Impact of the Aging Lens and Posterior Capsular Opacification on Quantitative Autofluorescence Imaging in Age-Related Macular Degeneration. Transl Vis Sci Technol 2022; 11:23. [PMID: 36239964 PMCID: PMC9586138 DOI: 10.1167/tvst.11.10.23] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Purpose The purpose of this study was to investigate quantitative autofluorescence (qAF8) in patients with and without early or intermediate age-related macular degeneration (AMD); to determine the impact of the aged crystalline lens and posterior capsular opacification (PCO). Methods In phakic and pseudophakic eyes ≥60 years, AMD status was determined by the Beckman system. PCO presence and severity was extracted from clinical records. qAF8 was calculated using custom FIJI plugins. Differences in qAF8, stratified by lens status, PCO severity, and AMD status, were analyzed using generalized estimating equations. Results In 210 eyes of 115 individuals (mean age = 75.7 ± 6.6 years), qAF8 was lower in intermediate AMD compared to early AMD (P = 0.05). qAF8 did not differ between phakic and pseudophakic eyes (P = 0.8909). In phakic (n = 83) and pseudophakic (n = 127) eyes considered separately, qAF8 did not differ by AMD status (P = 0.0936 and 0.3494, respectively). Qualitative review of qAF images in phakic eyes illustrated high variability. In pseudophakic eyes, qAF8 did not differ with PCO present versus absent (54.5% vs. 45.5%). Review of implanted intraocular lenses (IOLs) revealed that 43.9% were blue-filter IOLs. Conclusions qAF8 was not associated with AMD status, up to intermediate AMD, considering only pseudophakic eyes to avoid noisy images in phakic eyes. In pseudophakic eyes, qAF8 was not affected by PCO. Because blue-filter IOLs may reduce levels of exciting light for qAF8, future studies investigating qAF in eyes with different IOL types are needed. Translational Relevance To reduce variability in observational studies and clinical trials requiring qAF8, pseudophakic participants without blue-filter IOLs or advanced PCO should be preferentially enrolled.
Collapse
Affiliation(s)
- Andreas Berlin
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA,University Hospital Würzburg, Würzburg, Germany
| | - Mark E. Clark
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Thomas A. Swain
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nathan A. Fischer
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Gerald McGwin
- Department of Ophthalmology and Visual Sciences, 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
| | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Cynthia Owsley
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| |
Collapse
|
24
|
Fragiotta S, Parravano M, Sacconi R, Costanzo E, De Geronimo D, Prascina F, Capuano V, Souied EH, Han IC, Mullins R, Querques G. Sub-retinal pigment epithelium tubules in non-neovascular age-related macular degeneration. Sci Rep 2022; 12:15198. [PMID: 36071082 PMCID: PMC9452588 DOI: 10.1038/s41598-022-19193-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/25/2022] [Indexed: 11/22/2022] Open
Abstract
To describe a novel optical coherence tomography (OCT) signature resembling sub-retinal pigment epithelium (RPE) tubules (SRT) in non-neovascular age-related macular degeneration (AMD). Patients suffering from non-neovascular AMD with complete medical records and multimodal imaging were retrospectively revised in three different tertiary care centers. Multimodal imaging included color fundus photograph, spectral-domain OCT (Spectralis, Heidelberg Engineering, Germany), fundus autofluorescence, OCT angiography (RTVue XR Avanti, Optovue, Inc., Fremont, CA). A total of 7 eyes of 7 patients with drusenoid pigment epithelium detachment (PED) were consecutively analyzed. The sub-RPE tubules appeared as ovoidal structures with a hyperreflective contour and hyporeflective interior appreciable in the sub-RPE-basal lamina (BL) space on OCT B-scan. The anatomical location of the sub-RPE formations was lying above the Bruch’s membrane in 5/7 cases (71.4%) or floating in the sub-RPE-BL space in 2/7 cases (28.6%). En-face OCTA revealed a curvilinear tubulation-like structure corresponding to SRT without flow signal. Sub-RPE tubules represent a newly identified OCT signature observed in eyes with drusenoid PED. The presumed origin may include a variant of calcified structure or alternatively activated RPE cells with some residual BL or basal laminar deposits attracted to BrM for craving oxygen.
Collapse
Affiliation(s)
- Serena Fragiotta
- UniCamillus-Saint Camillus International University of Health Sciences, Rome, Italy
| | | | - Riccardo Sacconi
- Department of Ophthalmology, IRCCS Ospedale San Raffaele, University Vita-Salute, Via Olgettina, 60, 20132, Milan, Italy
| | | | | | - Francesco Prascina
- Department of Ophthalmology, IRCCS Ospedale San Raffaele, University Vita-Salute, Via Olgettina, 60, 20132, Milan, Italy
| | | | - Eric H Souied
- Centre Hospitalier Intercommunal de Creteil, Creteil, France
| | - Ian C Han
- The Institute for Vision Research, Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Robert Mullins
- The Institute for Vision Research, Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Giuseppe Querques
- Department of Ophthalmology, IRCCS Ospedale San Raffaele, University Vita-Salute, Via Olgettina, 60, 20132, Milan, Italy.
| |
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
Kotnala A, Senthilkumari S, Wu G, Stewart TG, Curcio CA, Halder N, Singh SB, Kumar A, Velpandian T. Retinal Pigment Epithelium in Human Donor Eyes Contains Higher Levels of Bisretinoids Including A2E in Periphery than Macula. Invest Ophthalmol Vis Sci 2022; 63:6. [PMID: 35671050 PMCID: PMC9187938 DOI: 10.1167/iovs.63.6.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose With age, human retinal pigment epithelium (RPE) accumulates bisretinoid fluorophores that may impact cellular function and contribute to age-related macular degeneration (AMD). Bisretinoids are comprised of a central pyridinium, dihydropyridinium, or cyclohexadiene ring. The pyridinium bisretinoid A2E has been extensively studied, and its quantity in the macula has been questioned. Age-changes and distributions of other bisretinoids are not well characterized. We measured levels of three bisretinoids and oxidized A2E in macula and periphery in human donor eyes of different ages. Methods Eyes (N = 139 donors, 61 women and 78 men, aged 40–80 years) were dissected into 8 mm diameter macular and temporal periphery punches. Using liquid chromatography – electrospray ionization – mass spectrometry (LC-ESI-MS) and an authentic synthesized standard, we quantified A2E (ng). Using LC-ESI-MS and a 50-eye-extract of A2E, we semiquantified A2E and 3 other compounds (eye extract equivalent units [EEEUs): A2-glycerophosphoethanolamine (A2GPE), dihydropyridine phosphatidyl ethanolamine (A2DHPE), and monofuranA2E (MFA2E). Results A2E quantities in ng and EEEUs were highly correlated (r = 0.97, P < 0.001). From 262 eyes, 5 to 9-fold higher levels were observed in the peripheral retina than in the macula for all assayed compounds. A2E, A2DHPE, and MFA2E increased with age, whereas A2GPE remained unaffected. No significant right-left or male-female differences were detected. Conclusions Significantly higher levels were observed in the periphery than in the macula for all assayed compounds signifying biologic differences between these regions. Levels of oxidized A2E parallel native A2E and not the distribution of retinal illuminance. Data will assist with the interpretion of clinical trial outcomes of agents targeting bisretinoid-related pathways.
Collapse
Affiliation(s)
- Ankita Kotnala
- Ocular Pharmacology & Pharmacy Division, All India Institute of Medical Sciences, New Delhi, India
| | - Srinivasan Senthilkumari
- Department of Ocular Pharmacology, Aravind Medical Research Foundation (AMRF), Dr. G. Venkataswamy Eye Research Institute, #1, Anna Nagar, Madurai -20, Tamilnadu, India
| | - Gong Wu
- Department of Biostatics, Vanderbilt University Medical Centre, Nashville, Tennessee, United States
| | - Thomas G Stewart
- Department of Biostatics, Vanderbilt University Medical Centre, Nashville, Tennessee, United States
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Nabanita Halder
- Ocular Pharmacology & Pharmacy Division, All India Institute of Medical Sciences, New Delhi, India
| | | | - Atul Kumar
- Department of Ophthalmology, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Thirumurthy Velpandian
- Ocular Pharmacology & Pharmacy Division, All India Institute of Medical Sciences, New Delhi, India
| |
Collapse
|
27
|
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.
Collapse
|
28
|
Różanowska MB, Różanowski B. Photodegradation of Lipofuscin in Suspension and in ARPE-19 Cells and the Similarity of Fluorescence of the Photodegradation Product with Oxidized Docosahexaenoate. Int J Mol Sci 2022; 23:ijms23020922. [PMID: 35055111 PMCID: PMC8778276 DOI: 10.3390/ijms23020922] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/07/2022] [Accepted: 01/12/2022] [Indexed: 02/01/2023] Open
Abstract
Retinal lipofuscin accumulates with age in the retinal pigment epithelium (RPE), where its fluorescence properties are used to assess retinal health. It was observed that there is a decrease in lipofuscin fluorescence above the age of 75 years and in the early stages of age-related macular degeneration (AMD). The purpose of this study was to investigate the response of lipofuscin isolated from human RPE and lipofuscin-laden cells to visible light, and to determine whether an abundant component of lipofuscin, docosahexaenoate (DHA), can contribute to lipofuscin fluorescence upon oxidation. Exposure of lipofuscin to visible light leads to a decrease in its long-wavelength fluorescence at about 610 nm, with a concomitant increase in the short-wavelength fluorescence. The emission spectrum of photodegraded lipofuscin exhibits similarity with that of oxidized DHA. Exposure of lipofuscin-laden cells to light leads to a loss of lipofuscin granules from cells, while retaining cell viability. The spectral changes in fluorescence in lipofuscin-laden cells resemble those seen during photodegradation of isolated lipofuscin. Our results demonstrate that fluorescence emission spectra, together with quantitation of the intensity of long-wavelength fluorescence, can serve as a marker useful for lipofuscin quantification and for monitoring its oxidation, and hence useful for screening the retina for increased oxidative damage and early AMD-related changes.
Collapse
Affiliation(s)
- Małgorzata B. Różanowska
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, UK
- Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Cardiff CF10 3NB, UK
- Correspondence: ; Tel.: +44-2920875057
| | - Bartosz Różanowski
- Institute of Biology, Pedagogical University of Kraków, 30-084 Kraków, Poland;
| |
Collapse
|
29
|
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.
Collapse
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
| |
Collapse
|
30
|
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.
Collapse
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)
| |
Collapse
|
31
|
Abstract
Light has a crucial role in the visual process. For nonvisible radiation in the short-wave spectrum, there are natural mechanisms that protect the human retina from damaging ultraviolet (UV) radiation. Here, the dose (= energy) makes the poison. Damage caused by UV light mainly affects the outer retina, particularly the photoreceptors and the retinal pigment epithelium. While retinal damage due to increased UV radiation exposure can potentially still occur up to the age of 20, in adulthood, exposure of the retina to UV radiation can no longer be assumed, due to decreasing transmission properties of the natural lens. The natural lens, modern intraocular lenses, and wearing of sunglasses with appropriate filter function, particularly in childhood and adolescence, provide a relevant reduction in UV radiation exposure of the retina.
Collapse
Affiliation(s)
| | - Thomas Ach
- Augenklinik, Universitätsklinikum Bonn, Venusberg-Campus 1, 53127, Bonn, Deutschland.
| |
Collapse
|
32
|
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.
Collapse
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
| |
Collapse
|
33
|
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.
Collapse
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.
| |
Collapse
|
34
|
Cao D, Leong B, Messinger JD, Kar D, Ach T, Yannuzzi LA, Freund KB, Curcio CA. Hyperreflective Foci, Optical Coherence Tomography Progression Indicators in Age-Related Macular Degeneration, Include Transdifferentiated Retinal Pigment Epithelium. Invest Ophthalmol Vis Sci 2021; 62:34. [PMID: 34448806 PMCID: PMC8399556 DOI: 10.1167/iovs.62.10.34] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose By optical coherence tomography (OCT) imaging, hyperreflective foci (HRF) indicate progression risk for advanced age-related macular degeneration (AMD) and are in part attributable to ectopic retinal pigment epithelium (RPE). We hypothesized that ectopic RPE are molecularly distinct from in-layer cells and that their cross-retinal course follows Müller glia. Methods In clinical OCT (61 eyes, 44 patients with AMD, 79.4 ± 7.7 years; 29 female; follow-up = 4.7 ± 0.9 years), one HRF type, RPE plume (n = 129 in 4 morphologies), was reviewed. Twenty eyes of 20 donors characterized by ex vivo OCT were analyzed by histology (normal, 4; early/intermediate AMD, 7; geographic atrophy, 6; neovascular AMD, 3). Cryosections were stained with antibodies to retinoid (RPE65, CRALPB) and immune (CD68, CD163) markers. In published RPE cellular phenotypes, red immunoreactivity was assessed semiquantitatively by one observer (none, some cells, all cells). Results Plume morphology evolved over time and many resolved (40%). Trajectories of RPE plume and cellular debris paralleled Müller glia, including near atrophy borders. RPE corresponding to HRF lost immunoreactivity for retinoid markers and gained immunoreactivity for immune markers. Aberrant immunoreactivity appeared in individual in-layer RPE cells and extended to all abnormal phenotypes. Müller glia remained CRALBP positive. Plume cells approached and contacted retinal capillaries. Conclusions HRF are indicators not predictors of overall disease activity. Gain and loss of function starts with individual in-layer RPE cells and extends to all abnormal phenotypes. Evidence for RPE transdifferentiation, possibly due to ischemia, supports a proposed process of epithelial–mesenchyme transition. Data can propel new biomarkers and therapeutic strategies for AMD.
Collapse
Affiliation(s)
- Dongfeng Cao
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Belinda Leong
- Vitreous Retina Macula Consultants of New York, New York, New York, United States.,Retina Associates, Sydney, New South Wales, Australia
| | - Jeffrey D Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | - Deepayan Kar
- 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 Bonn, Bonn, Germany
| | - Lawrence A Yannuzzi
- Vitreous Retina Macula Consultants of New York, New York, New York, United States.,LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York, United States
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, New York, United States.,LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York, United States.,Department of Ophthalmology, New York University, Grossman School of Medicine, 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
| |
Collapse
|
35
|
Masri RA, Weltzien F, Purushothuman S, Lee SCS, Martin PR, Grünert U. Composition of the Inner Nuclear Layer in Human Retina. Invest Ophthalmol Vis Sci 2021; 62:22. [PMID: 34259817 PMCID: PMC8288061 DOI: 10.1167/iovs.62.9.22] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to measure the composition of the inner nuclear layer (INL) in the central and peripheral human retina as foundation data for interpreting INL function and dysfunction. Methods Six postmortem human donor retinas (male and female, aged 31–56 years) were sectioned along the temporal horizontal meridian. Sections were processed with immunofluorescent markers and imaged using high-resolution, multichannel fluorescence microscopy. The density of horizontal, bipolar, amacrine, and Müller cells was quantified between 1 and 12 mm eccentricity with appropriate adjustments for postreceptoral spatial displacements near the fovea. Results Cone bipolar cells dominate the INL a with density near 50,000 cells/mm2 at 1 mm eccentricity and integrated total ∼10 million cells up to 10 mm eccentricity. Outside central retina the spatial density of all cell populations falls but the neuronal makeup of the INL remains relatively constant: a decrease in the proportion of cone bipolar cells (from 52% at 1 mm to 37% at 10 mm) is balanced by an increasing proportion of rod bipolar cells (from 9% to 15%). The proportion of Müller cells near the fovea (17%) is lower than in the peripheral retina (27%). Conclusions Despite large changes in the absolute density of INL cell populations across the retina, their proportions remain relatively constant. These data may have relevance for interpreting diagnostic signals such as the electroretinogram and optical coherence tomogram.
Collapse
Affiliation(s)
- Rania A Masri
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney, Australia
| | - Felix Weltzien
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, Sydney, Australia
| | - Sivaraman Purushothuman
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, Sydney, Australia
| | - Sammy C S Lee
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney, Australia
| | - Paul R Martin
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney, Australia
| | - Ulrike Grünert
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney, Australia
| |
Collapse
|
36
|
Cideciyan AV, Krishnan AK, Roman AJ, Sumaroka A, Swider M, Jacobson SG. Measures of Function and Structure to Determine Phenotypic Features, Natural History, and Treatment Outcomes in Inherited Retinal Diseases. Annu Rev Vis Sci 2021; 7:747-772. [PMID: 34255540 DOI: 10.1146/annurev-vision-032321-091738] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Inherited retinal diseases (IRDs) are at the forefront of innovative gene-specific treatments because of the causation by single genes, the availability of microsurgical access for treatment delivery, and the relative ease of quantitative imaging and vision measurement. However, it is not always easy to choose a priori, from scores of potential measures, an appropriate subset to evaluate efficacy outcomes considering the wide range of disease stages with different phenotypic features. This article reviews measurements of visual function and retinal structure that our group has used over the past three decades to understand the natural history of IRDs. We include measures of light sensitivity, retinal structure, mapping of natural fluorophores, evaluation of pupillary light reflex, and oculomotor control. We provide historical context and examples of applicability. We also review treatment trial outcomes using these measures of function and structure. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Arun K Krishnan
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Alejandro J Roman
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Alexander Sumaroka
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Malgorzata Swider
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| |
Collapse
|
37
|
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.
Collapse
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
| |
Collapse
|
38
|
Arslan J, Benke KK, Samarasinghe G, Sowmya A, Guymer RH, Baird PN. Model Structure Uncertainty in the Characterization and Growth of Geographic Atrophy. Transl Vis Sci Technol 2021; 10:2. [PMID: 34111247 PMCID: PMC8107635 DOI: 10.1167/tvst.10.6.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose To identify the most suitable model for assessing the rate of growth of total geographic atrophy (GA) by analysis of model structure uncertainty. Methods Model structure uncertainty refers to unexplained variability arising from the choice of mathematical model and represents an example of epistemic uncertainty. In this study, we quantified this uncertainty to help identify a model most representative of GA progression. Fundus autofluorescence (FAF) images and GA progression data (i.e., total GA area estimation at each presentation) were acquired using Spectralis HRA+OCT instrumentation and RegionFinder software. Six regression models were evaluated. Models were compared using various statistical tests, [i.e., coefficient of determination (r2), uncertainty metric (U), and test of significance for the correlation coefficient, r], as well as adherence to expected physical and clinical assumptions of GA growth. Results Analysis was carried out for 81 GA-affected eyes, 531 FAF images (range: 3–17 images per eye), over median of 57 months (IQR: 42, 74), with a mean baseline lesion size of 2.62 ± 4.49 mm2 (range: 0.11–20.69 mm2). The linear model proved to be the most representative of total GA growth, with lowest average uncertainty (original scale: U = 0.025, square root scale: U = 0.014), high average r2 (original scale: 0.92, square root scale: 0.93), and applicability of the model was supported by a high correlation coefficient, r, with statistical significance (P = 0.01). Conclusions Statistical analysis of uncertainty suggests that the linear model provides an effective and practical representation of the rate and progression of total GA growth based on data from patient presentations in clinical settings. Translational Relevance Identification of correct model structure to characterize rate of growth of total GA in the retina using FAF images provides an objective metric for comparing interventions and charting GA progression in clinical presentations.
Collapse
Affiliation(s)
- Janan Arslan
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye & Ear Hospital, East Melbourne, Victoria, Australia.,Department of Surgery, Ophthalmology, University of Melbourne, Parkville, Victoria, Australia
| | - Kurt K Benke
- School of Engineering, University of Melbourne, Parkville, Victoria, Australia.,Centre for AgriBioscience, AgriBio, Bundoora, Victoria, Australia
| | - Gihan Samarasinghe
- School of Computer Science and Engineering, University of New South Wales, Kensington, NSW, Australia
| | - Arcot Sowmya
- School of Computer Science and Engineering, University of New South Wales, Kensington, NSW, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye & Ear Hospital, East Melbourne, Victoria, Australia.,Department of Surgery, Ophthalmology, University of Melbourne, Parkville, Victoria, Australia
| | - Paul N Baird
- Department of Surgery, Ophthalmology, University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
39
|
Gao S, Li Y, Bissig D, Cohen ED, Podolsky RH, Childers KL, Vernon G, Chen S, Berkowitz BA, Qian H. Functional regulation of an outer retina hyporeflective band on optical coherence tomography images. Sci Rep 2021; 11:10260. [PMID: 33986362 PMCID: PMC8119672 DOI: 10.1038/s41598-021-89599-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/27/2021] [Indexed: 12/30/2022] Open
Abstract
Human and animal retinal optical coherence tomography (OCT) images show a hyporeflective band (HB) between the photoreceptor tip and retinal pigment epithelium layers whose mechanisms are unclear. In mice, HB magnitude and the external limiting membrane-retinal pigment epithelium (ELM-RPE) thickness appear to be dependent on light exposure, which is known to alter photoreceptor mitochondria respiration. Here, we test the hypothesis that these two OCT biomarkers are linked to metabolic activity of the retina. Acetazolamide, which acidifies the subretinal space, had no significant impact on HB magnitude but produced ELM-RPE thinning. Mitochondrial stimulation with 2,4-dinitrophenol reduced both HB magnitude and ELM-RPE thickness in parallel, and also reduced F-actin expression in the same retinal region, but without altering ERG responses. For mice strains with relatively lower (C57BL/6J) or higher (129S6/ev) rod mitochondrial efficacy, light-induced changes in HB magnitude and ELM-RPE thickness were correlated. Humans, analyzed from published data captured with a different protocol, showed a similar light–dark change pattern in HB magnitude as in the mice. Our results indicate that mitochondrial respiration underlies changes in HB magnitude upstream of the pH-sensitive ELM-RPE thickness response. These two distinct OCT biomarkers could be useful indices for non-invasively evaluating photoreceptor mitochondrial metabolic activity.
Collapse
Affiliation(s)
- Shasha Gao
- Department of Ophthalmology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China.,Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yichao Li
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - David Bissig
- Department of Neurology, University of California Davis, Sacramento, CA, USA
| | - Ethan D Cohen
- Division of Biomedical Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
| | - Robert H Podolsky
- Beaumont Research Institute, Beaumont Health, Royal Oak, MI, 48073, USA
| | | | - Gregory Vernon
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sonia Chen
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Bruce A Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, USA
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
40
|
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.
Collapse
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
| |
Collapse
|
41
|
Tong Y, Ach T, Curcio CA, Smith RT. Hyperspectral autofluorescence characterization of drusen and sub-RPE deposits in age-related macular degeneration. ACTA ACUST UNITED AC 2021; 6. [PMID: 33791592 PMCID: PMC8009528 DOI: 10.21037/aes-20-12] [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: 11/09/2022]
Abstract
Background: Soft drusen and basal linear deposit (BLinD) are two forms of the same extracellular lipid rich material that together make up an Oil Spill on Bruch’s membrane (BrM). Drusen are focal and can be recognized clinically. In contrast BLinD is thin and diffusely distributed, and invisible clinically, even on highest resolution OCT, but has been detected on en face hyperspectral autofluorescence (AF) imaging ex vivo. We sought to optimize histologic hyperspectral AF imaging and image analysis for recognition of drusen and sub-RPE deposits (including BLinD and basal laminar deposit), for potential clinical application. Methods: Twenty locations specifically with drusen and 12 additional locations specifically from fovea, perifovea and mid-periphery from RPE/BrM flatmounts from 4 AMD donors underwent hyperspectral AF imaging with 4 excitation wavelengths (λex 436, 450, 480 and 505 nm), and the resulting image cubes were simultaneously decomposed with our published non-negative matrix factorization (NMF). Rank 4 recovery of 4 emission spectra was chosen for each excitation wavelength. Results: A composite emission spectrum, sensitive and specific for drusen and presumed sub-RPE deposits (the SDr spectrum) was recovered with peak at 510–520 nm in all tissues with drusen, with greatest amplitudes at excitations λex 436, 450 and 480 nm. The RPE spectra of combined sources Lipofuscin (LF)/Melanolipofuscin (MLF) were of comparable amplitude and consistently recapitulated the spectra S1, S2 and S3 previously reported from all tissues: tissues with drusen, foveal and extra-foveal locations. Conclusions: A clinical hyperspectral AF camera, with properly chosen excitation wavelengths in the blue range and a hyperspectral AF detector, should be capable of detecting and quantifying drusen and sub-RPE deposits, the earliest known lesions of AMD, before any other currently available imaging modality.
Collapse
Affiliation(s)
- Yuehong Tong
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Thomas Ach
- Department of Ophthalmology, University Hospital Bonn, Germany
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, AL, USA
| | - R Theodore Smith
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| |
Collapse
|
42
|
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.
Collapse
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
| |
Collapse
|
43
|
Chen L, Messinger JD, Kar D, Duncan JL, Curcio CA. Biometrics, Impact, and Significance of Basal Linear Deposit and Subretinal Drusenoid Deposit in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2021; 62:33. [PMID: 33512402 PMCID: PMC7846955 DOI: 10.1167/iovs.62.1.33] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/04/2021] [Indexed: 02/07/2023] Open
Abstract
Purpose Basal linear deposit (BLinD) is a thin layer of soft drusen material. To elucidate the biology of extracellular deposits conferring age-related macular degeneration (AMD) progression risk and inform multimodal clinical imaging based on optical coherence tomography (OCT), we examined lipid content and regional prevalence of BLinD, soft drusen, pre-BLinD, and subretinal drusenoid deposit (SDD) in AMD and non-AMD aged eyes. We estimated BLinD volume and illustrated its relation to type 1 macular neovascularization (MNV). Methods Donor eyes were classified as early to intermediate AMD (n = 25) and age-matched controls (n = 54). In high-resolution histology, we assessed BLinD/soft drusen thickness at 836 and 1716 locations in AMD and control eyes, respectively. BLinD volume was estimated using solid geometry in donor eyes, one clinically characterized. Results BLinD, drusen, type 1 MNV, and fluid occupy the sub-RPE-basal laminar space. BLinD volume in a 3-mm diameter circle may be as much as 0.0315 mm3. Osmophilic lipid was more concentrated in BLinD/drusen than SDD. In the fovea, BLinD/drusen was prevalent in AMD eyes; pre-BLinD was prevalent in control eyes. SDD was low in the fovea and high in perifovea, especially in AMD eyes. Conclusions Although invisible, BLinD may presage type 1 MNV. BLinD volume approaches the criterion OCT drusen volume of 0.03 mm3 for AMD progression risk. BLinD culminates years of subfoveal lipid accumulation. SDD is detected relatively late in life, with currently unknown precursors. Deposit topography suggests one outer retinal lipid recycling system serving specialized cone and rod physiology, and its dysregulation in AMD is due to impaired transfer to the circulation.
Collapse
Affiliation(s)
- Ling Chen
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, and Chongqing Eye Institute, Chongqing, China
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jeffrey D. Messinger
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Deepayan Kar
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jacque L. Duncan
- Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| |
Collapse
|
44
|
Lee AY, Lee CS, Blazes MS, Owen JP, Bagdasarova Y, Wu Y, Spaide T, Yanagihara RT, Kihara Y, Clark ME, Kwon M, Owsley C, Curcio CA. Exploring a Structural Basis for Delayed Rod-Mediated Dark Adaptation in Age-Related Macular Degeneration Via Deep Learning. Transl Vis Sci Technol 2020; 9:62. [PMID: 33344065 PMCID: PMC7745629 DOI: 10.1167/tvst.9.2.62] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/30/2020] [Indexed: 01/09/2023] Open
Abstract
Purpose Delayed rod-mediated dark adaptation (RMDA) is a functional biomarker for incipient age-related macular degeneration (AMD). We used anatomically restricted spectral domain optical coherence tomography (SD-OCT) imaging data to localize de novo imaging features associated with and to test hypotheses about delayed RMDA. Methods Rod intercept time (RIT) was measured in participants with and without AMD at 5 degrees from the fovea, and macular SD-OCT images were obtained. A deep learning model was trained with anatomically restricted information using a single representative B-scan through the fovea of each eye. Mean-occlusion masking was utilized to isolate the relevant imaging features. Results The model identified hyporeflective outer retinal bands on macular SD-OCT associated with delayed RMDA. The validation mean standard error (MSE) registered to the foveal B-scan localized the lowest error to 0.5 mm temporal to the fovea center, within an overall low-error region across the rod-free zone and adjoining parafovea. Mean absolute error (MAE) on the test set was 4.71 minutes (8.8% of the dynamic range). Conclusions We report a novel framework for imaging biomarker discovery using deep learning and demonstrate its ability to identify and localize a previously undescribed biomarker in retinal imaging. The hyporeflective outer retinal bands in central macula on SD-OCT demonstrate a structural basis for dysfunctional rod vision that correlates to published histopathologic findings. Translational Relevance This agnostic approach to anatomic biomarker discovery strengthens the rationale for RMDA as an outcome measure in early AMD clinical trials, and also expands the utility of deep learning beyond automated diagnosis to fundamental discovery.
Collapse
Affiliation(s)
- Aaron Y Lee
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Cecilia S Lee
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Marian S Blazes
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Julia P Owen
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Yelena Bagdasarova
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Yue Wu
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Theodore Spaide
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Ryan T Yanagihara
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Yuka Kihara
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Mark E Clark
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - MiYoung Kwon
- Department of Psychology, Northeastern University, Boston, MA, USA
| | - Cynthia Owsley
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| |
Collapse
|
45
|
Anderson DMG, Messinger JD, Patterson NH, Rivera ES, Kotnala A, Spraggins JM, Caprioli RM, Curcio CA, Schey KL. Lipid Landscape of the Human Retina and Supporting Tissues Revealed by High-Resolution Imaging Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:2426-2436. [PMID: 32628476 PMCID: PMC8161663 DOI: 10.1021/jasms.0c00119] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The human retina provides vision at light levels ranging from starlight to sunlight. Its supporting tissues regulate plasma-delivered lipophilic essentials for vision, including retinoids. The macula is an anatomic specialization for high-acuity and color vision that is also vulnerable to prevalent blinding diseases. The retina's exquisite architecture comprises numerous cell types that are aligned horizontally, yielding structurally distinct cell, synaptic, and vascular layers that are visible in histology and in diagnostic clinical imaging. MALDI imaging mass spectrometry (IMS) is now capable of uniting low micrometer spatial resolution with high levels of chemical specificity. In this study, a multimodal imaging approach fortified with accurate multi-image registration was used to localize lipids in human retina tissue at laminar, cellular, and subcellular levels. Multimodal imaging results indicate differences in distributions and abundances of lipid species across and within single cell types. Of note are distinct localizations of signals within specific layers of the macula. For example, phosphatidylethanolamine and phosphatidylinositol lipids were localized to central RPE cells, whereas specific plasmalogen lipids were localized to cells of the perifoveal RPE and Henle fiber layer. Subcellular compartments of photoreceptors were distinguished by PE(20:0_22:5) in the outer nuclear layer, PE(18:0_22:6) in outer and inner segments, and cardiolipin CL(70:5) in the mitochondria-rich inner segments. Several lipids, differing by a single double bond, have markedly different distributions between the central fovea and the ganglion cell and inner nuclear layers. A lipid atlas, initiated in this study, can serve as a reference database for future examination of diseased tissues.
Collapse
Affiliation(s)
- David M G Anderson
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Jeffrey D Messinger
- Department of Ophthalmology and Visual Science, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Nathan H Patterson
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Emilio S Rivera
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Ankita Kotnala
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department of Ophthalmology and Visual Science, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Jeffrey M Spraggins
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Richard M Caprioli
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Christine A Curcio
- Department of Ophthalmology and Visual Science, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Kevin L Schey
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37240, United States
| |
Collapse
|
46
|
Wynne N, Carroll J, Duncan JL. Promises and pitfalls of evaluating photoreceptor-based retinal disease with adaptive optics scanning light ophthalmoscopy (AOSLO). Prog Retin Eye Res 2020; 83:100920. [PMID: 33161127 DOI: 10.1016/j.preteyeres.2020.100920] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/28/2020] [Accepted: 10/31/2020] [Indexed: 12/15/2022]
Abstract
Adaptive optics scanning light ophthalmoscopy (AOSLO) allows visualization of the living human retina with exquisite single-cell resolution. This technology has improved our understanding of normal retinal structure and revealed pathophysiological details of a number of retinal diseases. Despite the remarkable capabilities of AOSLO, it has not seen the widespread commercial adoption and mainstream clinical success of other modalities developed in a similar time frame. Nevertheless, continued advancements in AOSLO hardware and software have expanded use to a broader range of patients. Current devices enable imaging of a number of different retinal cell types, with recent improvements in stimulus and detection schemes enabling monitoring of retinal function, microscopic structural changes, and even subcellular activity. This has positioned AOSLO for use in clinical trials, primarily as exploratory outcome measures or biomarkers that can be used to monitor disease progression or therapeutic response. AOSLO metrics could facilitate patient selection for such trials, to refine inclusion criteria or to guide the choice of therapy, depending on the presence, absence, or functional viability of specific cell types. Here we explore the potential of AOSLO retinal imaging by reviewing clinical applications as well as some of the pitfalls and barriers to more widespread clinical adoption.
Collapse
Affiliation(s)
- Niamh Wynne
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA.
| |
Collapse
|
47
|
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.
Collapse
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
| |
Collapse
|