Dataset Information

Choroidal and Sub-Retinal Pigment Epithelium Caverns: Multimodal Imaging and Correspondence with Friedman Lipid Globules.

ABSTRACT: PURPOSE:To survey Friedman lipid globules by high-resolution histologic examination and to compare with multimodal imaging of hyporeflective caverns in eyes with geographic atrophy (GA) secondary to age-related macular (AMD) and other retinal diseases. DESIGN:Histologic survey of donor eyes with and without AMD. Clinical case series with multimodal imaging analysis. PARTICIPANTS:Donor eyes (n = 139; 26 with early AMD, 13 with GA, 40 with nAMD, 52 with a healthy macula, and 8 with other or unknown characteristics) and 41 eyes of 28 participants with GA (n = 16), nAMD (n = 8), Stargardt disease (n = 4), cone dystrophy (n = 2), pachychoroid spectrum (n = 6), choroidal hemangioma (n = 1), and healthy eyes (n = 4). METHODS:Donor eyes were prepared for macula-wide epoxy resin sections through the foveal and perifoveal area. In patients, caverns were identified as nonreflective spaces on OCT images. Multimodal imaging included color and red-free fundus photography; fundus autofluorescence; fluorescein and, indocyanine green angiography; OCT angiography; near-infrared reflectance; and confocal multispectral (MultiColor [Spectralis, Heidelberg Engineering, Germany]) imaging. MAIN OUTCOME MEASURES:Presence and morphologic features of globules, and presence and appearance of caverns on multimodal imaging. RESULTS:Globules were found primarily in the inner choroidal stroma (91.0%), but also localized to the sclera (4.9%) and neovascular membranes (2.1%). Mean diameters of solitary and multilobular globules were 58.9±37.8 ?m and 65.4±27.9 ?m, respectively. Globules showed morphologic signs of dynamism including pitting, dispersion, disintegration, and crystal formation. Evidence for inflammation in the surrounding tissue was absent. En face OCT rendered sharply delimited hyporeflective areas as large as choroidal vessels, frequently grouped around choroid vessels or in the neovascular tissue. Cross-sectional OCT revealed a characteristic posterior hypertransmission. OCT angiography showed absence of flow signal within caverns. CONCLUSIONS:Based on prior literature documenting OCT signatures of tissue lipid in atheroma and nAMD, we speculate that caverns are lipid rich. Globules, with similar sizes and tissue locations in AMD and healthy persons, are candidates for histologic correlates of caverns. The role of globules in chorioretinal physiologic features, perhaps as a lipid depot for photoreceptor metabolism, is approachable through clinical imaging.

SUBMITTER: Dolz-Marco R

PROVIDER: S-EPMC6321740 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Choroidal and Sub-Retinal Pigment Epithelium Caverns: Multimodal Imaging and Correspondence with Friedman Lipid Globules.

Dolz-Marco Rosa R Glover Jay P JP Gal-Or Orly O Litts Katie M KM Messinger Jeffrey D JD Zhang Yuhua Y Cozzi Mariano M Pellegrini Marco M Freund K Bailey KB Staurenghi Giovanni G Curcio Christine A CA

Ophthalmology 20180404 8

<h4>Purpose</h4>To survey Friedman lipid globules by high-resolution histologic examination and to compare with multimodal imaging of hyporeflective caverns in eyes with geographic atrophy (GA) secondary to age-related macular (AMD) and other retinal diseases.<h4>Design</h4>Histologic survey of donor eyes with and without AMD. Clinical case series with multimodal imaging analysis.<h4>Participants</h4>Donor eyes (n = 139; 26 with early AMD, 13 with GA, 40 with nAMD, 52 with a healthy macula, and ...[more]

PMID: 29625839

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Project description:Background: To identify and functionally annotate cell type-specific gene expression in the human retinal pigment epithelium (RPE), a key tissue involved in age-related macular degeneration and retinitis pigmentosa. Methodology: RPE, photoreceptor and choroidal cells were isolated from selected freshly frozen healthy human donor eyes using laser microdissection. RNA isolation, amplification and hybridization to 44k microarrays was carried out according to Agilent specifications. Bioinformatics was carried out using Rosetta Resolver, David and Ingenuity software. Principal Findings: Our previous 22k analysis of the RPE transcriptome showed that the RPE has high levels of protein synthesis, strong energy demands, is exposed to high levels of oxidative stress and a variable degree of inflammation. We currently use a complementary new strategy aimed at the identification and functional annotation of RPE-specific expressed transcripts. This strategy takes advantage of the multilayered cellular structure of the retina and overcomes a number of limitations of previous studies. In triplicate, we compared the transcriptomes of RPE, photoreceptor and choroidal cells and we deduced RPE specific expression. We identified at least 114 entries with RPE-specific gene expression. Thirty-nine of these 114 genes also show high expression in the RPE, comparison with the literature showed that 85% of these 39 were previously identified to be expressed in the RPE. In the group of 114 RPE specific genes there was an overrepresentation of genes involved in (membrane) transport, vision and ophthalmic disease. More fundamentally, we found RPE-specific involvement in the RAR-activation, retinol metabolism and GABA receptor signaling pathways. Conclusions: In this study we provide a further specification and understanding of the RPE transcriptome by identifying and analyzing genes that are specifically expressed in the RPE. Six RPE samples, three phot samples, three choroid samples

Project description:Lipofuscin accumulates with age in the retinal pigment epithelium (RPE) in discrete granular organelles and may contribute to age-related macular degeneration. Because previous studies suggest that lipofuscin contains protein that may impact pathogenic mechanisms, we pursued proteomics analysis of lipofuscin. The composition of RPE lipofuscin and its mechanisms of pathogenesis are poorly understood in part because of the heterogeneity of isolated preparations. We purified RPE lipofuscin granules by treatment with proteinase K or SDS and showed by light, confocal, and transmission electron microscopy that the purified granules are free of extragranular material and associated membranes. Crude and purified lipofuscin preparations were quantitatively compared by (i) LC MS/MS proteomics analyses, (ii) immunoanalyses of oxidative protein modifications, (iii) amino acid analysis, (iv) HPLC of bisretinoids, and (v) assaying phototoxicity to RPE cells. From crude lipofuscin preparations 186 proteins were identified, many of which appeared to be modified. In contrast, very little protein ( approximately 2% (w/w) by amino acid analysis) and no identifiable protein were found in the purified granules, which retained full phototoxicity to cultured RPE cells. Our analyses showed that granules in purified and crude lipofuscin preparations exhibit no statistically significant differences in diameter or circularity or in the content of the bisretinoids A2E, isoA2E, and all-trans-retinal dimer-phosphatidylethanolamine. The finding that the purified granules contain minimal protein yet retain phototoxic activity suggests that RPE lipofuscin pathogenesis is largely independent of associated protein. The purified granules also exhibited oxidative protein modifications, including nitrotyrosine generated from reactive nitrogen oxide species and carboxyethylpyrrole and iso[4]levuglandin E(2) adducts generated from reactive lipid fragments. This finding is consistent with previous studies demonstrating RPE lipofuscin to be a potent generator of reactive oxygen species and supports the hypothesis that such species, including reactive fragments from lipids and retinoids, contribute to the mechanisms of RPE lipofuscin pathogenesis.

Dataset Information

Choroidal and Sub-Retinal Pigment Epithelium Caverns: Multimodal Imaging and Correspondence with Friedman Lipid Globules.

Publications

Choroidal and Sub-Retinal Pigment Epithelium Caverns: Multimodal Imaging and Correspondence with Friedman Lipid Globules.

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