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Yi W, Lv D, Sun Y, Mu J, Lu X. Role of APOE in glaucoma. Biochem Biophys Res Commun 2024; 694:149414. [PMID: 38145596 DOI: 10.1016/j.bbrc.2023.149414] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 12/27/2023]
Abstract
Glaucoma is a chronic blinding eye disease caused by the progressive loss of retinal ganglion cells (RGCs). Currently, no clinically approved treatment can directly improve the survival rate of RGCs. The Apolipoprotein E (APOE) gene is closely related to the genetic risk of numerous neurodegenerative diseases and has become a hot topic in the field of neurodegenerative disease research in recent years. The optic nerve and retina are extensions of the brain's nervous system. The pathogenesis of retinal degenerative diseases is closely related to the degenerative diseases of the nerves in the brain. APOE consists of three alleles, ε4, ε3, and ε2, in a single locus. They have varying degrees of risk for glaucoma. APOE4 and the APOE gene deletion (APOE-/-) can reduce RGC loss. By contrast, APOE3 and the overall presence of APOE genes (APOE+/+) result in significant loss of RGC bodies and axons, increasing the risk of glaucoma RGCs death. Currently, there is no clear literature indicating that APOE2 is beneficial or harmful to glaucoma. This study summarises the mechanism of different APOE genes in glaucoma and speculates that APOE targeted intervention may be a promising method for protecting against RGCs loss in glaucoma.
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Affiliation(s)
- Wenhua Yi
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - De Lv
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, China.
| | - Yue Sun
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - Jingyu Mu
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - Xuejing Lu
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China; Ineye Hospital of Chengdu University of TCM, Chengdu City, Sichuan province, China; Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection with TCM Laboratory, Chengdu City, Sichuan province, China; Retinal Image Technology and Chronic Vascular Disease Prevention&Control and Collaborative Innovation Center, Chengdu City, Sichuan province, China.
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2
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Sonntag SR, Klein B, Brinkmann R, Grisanti S, Miura Y. Fluorescence Lifetime Imaging Ophthalmoscopy of Mouse Models of Age-related Macular Degeneration. Transl Vis Sci Technol 2024; 13:24. [PMID: 38285461 PMCID: PMC10829802 DOI: 10.1167/tvst.13.1.24] [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: 07/23/2023] [Accepted: 12/21/2023] [Indexed: 01/30/2024] Open
Abstract
Purpose To investigate fluorescence lifetime of mouse models of age-related macular degeneration (AMD) by fluorescence lifetime imaging ophthalmoscopy (FLIO). Methods Two AMD mouse models, apolipoprotein E knockout (ApoE-/-) mice and NF-E2-related factor-2 knockout (Nrf2-/-) mice, and their wild-type mice underwent monthly ophthalmic examinations including FLIO from 3 months of age. After euthanasia at the age of 6 or 11 months, blood plasma was collected to determine total antioxidant capacity and eyes were enucleated for Oil red O (ORO) lipid staining of chorioretinal tissue. Results In FLIO, the mean fluorescence lifetime (τm) of wild type shortened with age in both spectral channels. In short spectral channel, τm shortening was observed in both AMD models as well, but its rate was more pronounced in ApoE-/- mice and significantly different from the other strains as months of age progressed. In contrast, in long spectral channel, both model strains showed completely opposite trends, with τm becoming shorter in ApoE-/- and longer in Nrf2-/- mice than the others. Oil red O staining at Bruch's membrane was significantly stronger in ApoE-/- mice at 11 months than the other strains. Plasma total antioxidant capacity was highest in ApoE-/- mice at both 6 and 11 months. Conclusions The two AMD mouse models exhibited largely different fundus fluorescence lifetime, which might be related to the different systemic metabolic state. FLIO might be able to indicate different metabolic states of eyes at risk for AMD. Translational Relevance This animal study may provide new insights into the relationship between early AMD-associated metabolic changes and FLIO findings.
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Affiliation(s)
- Svenja Rebecca Sonntag
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Britta Klein
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
- Medical Laser Center Lübeck, Lübeck, Germany
| | - Ralf Brinkmann
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
- Medical Laser Center Lübeck, Lübeck, Germany
| | - Salvatore Grisanti
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Yoko Miura
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
- Medical Laser Center Lübeck, Lübeck, Germany
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3
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Sreekumar PG, Su F, Spee C, Araujo E, Nusinowitz S, Reddy ST, Kannan R. Oxidative Stress and Lipid Accumulation Augments Cell Death in LDLR-Deficient RPE Cells and Ldlr-/- Mice. Cells 2022; 12:43. [PMID: 36611838 PMCID: PMC9818299 DOI: 10.3390/cells12010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/14/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022] Open
Abstract
Lipid peroxidation from oxidative stress is considered a major contributor to age-related macular degeneration (AMD). The retina is abundant with circulating low-density lipoproteins (LDL), which are taken up by LDL receptor (LDLR) in the RPE and Müller cells. The purpose of this study is to investigate the role of LDLR in the NaIO3-induced model of dry AMD. Confluent primary human RPE (hRPE) and LDLR-silenced ARPE-19 cells were stressed with 150 µM tert-butyl hydroperoxide (tBH) and caspase 3/7 activation was determined. WT and Ldlr-/- mice were administered NaIO3 (20 mg/kg) intravenously. On day 7, fundus imaging, OCT, ERG, and retinal thickness were measured. Histology, TUNEL, cleaved caspase 3 and lipid accumulation were assessed. Treatment of hRPE with tBH markedly decreased LDLR expression. Caspase 3/7 activation was significantly increased in LDLR-silenced ARPE-19 cells treated with tBH. In Ldlr-/- mice, NaIO3 administration resulted in significant (a) retinal thinning, (b) compromised photoreceptor function, (c) increased percentage of cleaved caspase 3 positive and apoptotic cells, and (d) increased lipid droplet accumulation in the RPE, Bruch membrane, choroid, and sclera, compared to WT mice. Our findings imply that LDLR loss leads to lipid accumulation and impaired retinal function, which may contribute to the development of AMD.
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Affiliation(s)
| | - Feng Su
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | | | - Eduardo Araujo
- Jules Stein Eye Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Steven Nusinowitz
- Jules Stein Eye Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Srinivasa T Reddy
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Ram Kannan
- Doheny Eye Institute, Pasadena, CA 91103, USA
- Jules Stein Eye Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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4
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Choudhary M, Tayyari F, Handa JT, Malek G. Characterization and identification of measurable endpoints in a mouse model featuring age-related retinal pathologies: a platform to test therapies. J Transl Med 2022; 102:1132-1142. [PMID: 36775353 PMCID: PMC10041606 DOI: 10.1038/s41374-022-00795-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/13/2022] [Accepted: 04/18/2022] [Indexed: 11/09/2022] Open
Abstract
Apolipoprotein B100 (apoB100) is the structural protein of cholesterol carriers including low-density lipoproteins. It is a constituent of sub-retinal pigment epithelial (sub-RPE) deposits and pro-atherogenic plaques, hallmarks of early dry age-related macular degeneration (AMD), an ocular neurodegenerative blinding disease, and cardiovascular disease, respectively. Herein, we characterized the retinal pathology of transgenic mice expressing mouse apoB100 in order to catalog their functional and morphological ocular phenotypes as a function of age and establish measurable endpoints for their use as a mouse model to test potential therapies. ApoB100 mice were found to exhibit an age-related decline in retinal function, as measured by electroretinogram (ERG) recordings of their scotopic a-wave, scotopic b-wave; and c-wave amplitudes. ApoB100 mice also displayed a buildup of the cholesterol carrier, apolipoprotein E (apoE) within and below the supporting extracellular matrix, Bruch's membrane (BrM), along with BrM thickening, and accumulation of thin diffuse electron-dense sub-RPE deposits, the severity of which increased with age. Moreover, the combination of apoB100 and advanced age were found to be associated with RPE morphological changes and the presence of sub-retinal immune cells as visualized in RPE-choroid flatmounts. Finally, aged apoB100 mice showed higher levels of circulating and ocular pro-inflammatory cytokines, supporting a link between age and increased local and systemic inflammation. Collectively, the data support the use of aged apoB100 mice as a platform to evaluate potential therapies for retinal degeneration, specifically drugs intended to target removal of lipids from Bruch's membrane and/or alleviate ocular inflammation.
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Affiliation(s)
- Mayur Choudhary
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Faryan Tayyari
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - James T Handa
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Goldis Malek
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA; Department of Pathology, Duke University School of Medicine, Durham, NC, USA.
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5
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Cao X, Guo Y, Wang Y, Wang H, Liu D, Gong Y, Wang J, Chen X, Zhang W. Effects of high-fat diet and Apoe deficiency on retinal structure and function in mice. Sci Rep 2020; 10:18601. [PMID: 33139746 PMCID: PMC7606505 DOI: 10.1038/s41598-020-75576-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 10/16/2020] [Indexed: 12/17/2022] Open
Abstract
To investigate the effects of a high-fat diet (HFD) and apolipoprotein E (Apoe) deficiency on retinal structure and function in mice. Apoe KO mice and wild-type C57BL/6J mice were given a low-fat diet (LFD) or a HFD for 32 weeks. Blood glucose, serum lipids, body weight and visceral fat weight were evaluated. Retinal sterol quantification was carried out by isotope dilution gas chromatography-mass spectrometry. The cholesterol metabolism related genes SCAP-SREBP expressions were detected by qRT-PCR. Retinal function was recorded using an electroretinogram. The thickness of each layer of the retina was measured by optical coherence tomography. Fundus fluorescein angiography was performed to detect retinal vasculature changes. Immunohistochemical staining was used to determine the expression of NF-κB, TNF-α and VEGFR2 in the retina among HFD, HFD Apoe-/-, LFD Apoe-/- and WT mice retinas. HFD feeding caused the mice to gain weight and develop hypercholesterinemia, while Apoe-/- abnormalities also affected blood lipid metabolism. Both HFD and Apoe deficiency elevated retinal cholesterol, especially in the HFD Apoe-/- mice. No up-regulated expression of SCAP-SREBP was observed as a negative regulator. Impaired retinal functions, thinning retinas and abnormal retinal vasculature were observed in the peripheral retinas of the HFD and Apoe-/- mice compared with those in the normal chow group, particularly in the HFD Apoe-/- mice. Moreover, the expression of NF-κB in the retinas of the HFD and Apoe-/- mice was increased, together with upregulated TNF-α mRNA levels and TNF-α expression in the layer of retinal ganglion cells of the peripheral retina. At the same time, the expression level of VEGFR2 was elevated in the intervention groups, most notably in HFD Apoe-/- mice. HFD or Apoe gene deletion had certain adverse effects on retinal function and structure, which were far below the combined factors and induced harm to the retina. Furthermore, HFD caused retinal ischemia and hypoxia. Additionally, Apoe abnormality increased susceptibility to ischemia. These changes upregulated NF-κB expression in ganglion cells and activated downstream TNF-α. Simultaneously, they activated VEGFR2, accelerating angiogenesis and vascular permeability. All of the aforementioned outcomes initiated inflammatory responses to trigger ganglion cell apoptosis and aggravate retinal neovascularization.
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Affiliation(s)
- Xiupeng Cao
- Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin, China.,Nankai University Affiliated Eye Hospital, Tianjin, China
| | - Yatu Guo
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin, China. .,Nankai University Affiliated Eye Hospital, Tianjin, China.
| | - Yuchuan Wang
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin, China.,Nankai University Affiliated Eye Hospital, Tianjin, China
| | - Hao Wang
- State Key Laboratory of Food Nutrition and Safety, Tianjin University of Science and Technology, Tianjin, China
| | - Dong Liu
- State Key Laboratory of Food Nutrition and Safety, Tianjin University of Science and Technology, Tianjin, China
| | - Yibo Gong
- Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin, China.,Nankai University Affiliated Eye Hospital, Tianjin, China
| | - Jue Wang
- Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin, China.,Nankai University Affiliated Eye Hospital, Tianjin, China
| | - Xia Chen
- Tianjin Medical University, Tianjin, China. .,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin, China. .,Nankai University Affiliated Eye Hospital, Tianjin, China.
| | - Wei Zhang
- Tianjin Medical University, Tianjin, China. .,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin, China. .,Nankai University Affiliated Eye Hospital, Tianjin, China.
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Studies of ApoD -/- and ApoD -/-ApoE -/- mice uncover the APOD significance for retinal metabolism, function, and status of chorioretinal blood vessels. Cell Mol Life Sci 2020; 78:963-983. [PMID: 32440710 DOI: 10.1007/s00018-020-03546-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/15/2020] [Accepted: 05/07/2020] [Indexed: 12/26/2022]
Abstract
Apolipoprotein D (APOD) is an atypical apolipoprotein with unknown significance for retinal structure and function. Conversely, apolipoprotein E (APOE) is a typical apolipoprotein with established roles in retinal cholesterol transport. Herein, we immunolocalized APOD to the photoreceptor inner segments and conducted ophthalmic characterizations of ApoD-/- and ApoD-/-ApoE-/- mice. ApoD-/- mice had normal levels of retinal sterols but changes in the chorioretinal blood vessels and impaired retinal function. The whole-body glucose disposal was impaired in this genotype but the retinal glucose metabolism was unchanged. ApoD-/-ApoE-/- mice had altered sterol profile in the retina but apparently normal chorioretinal vasculature and function. The whole-body glucose disposal and retinal glucose utilization were enhanced in this genotype. OB-Rb, both leptin and APOD receptor, was found to be expressed in the photoreceptor inner segments and was at increased abundance in the ApoD-/- and ApoD-/-ApoE-/- retinas. Retinal levels of Glut4 and Cd36, the glucose transporter and scavenger receptor, respectively, were increased as well, thus linking APOD to retinal glucose and fatty acid metabolism and suggesting the APOD-OB-Rb-GLUT4/CD36 axis. In vivo isotopic labeling, transmission electron microscopy, and retinal proteomics provided additional insights into the mechanism underlying the retinal phenotypes of ApoD-/- and ApoD-/-ApoE-/- mice. Collectively, our data suggest that the APOD roles in the retina are context specific and could determine retinal glucose fluxes into different pathways. APOD and APOE do not play redundant, complementary or opposing roles in the retina, rather their interplay is more complex and reflects retinal responses elicited by lack of these apolipoproteins.
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7
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Saadane A, Petrov A, Mast N, El-Darzi N, Dao T, Alnemri A, Song Y, Dunaief JL, Pikuleva IA. Mechanisms that minimize retinal impact of apolipoprotein E absence. J Lipid Res 2018; 59:2368-2382. [PMID: 30333155 DOI: 10.1194/jlr.m090043] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/17/2018] [Indexed: 01/28/2023] Open
Abstract
Apolipoprotein E (APOE) is a component of lipid-transporting particles and a recognition ligand for receptors, which bind these particles. The APOE isoform ε2 is a risk factor for age-related macular degeneration; nevertheless, APOE absence in humans and mice does not significantly affect the retina. We found that retinal cholesterol biosynthesis and the levels of retinal cholesterol were increased in Apoe-/- mice, whereas cholesterol elimination by metabolism was decreased. No focal cholesterol deposits were observed in the Apoe-/- retina. Retinal proteomics identified the most abundant cholesterol-related proteins in WT mice and revealed that, of these cholesterol-related proteins, only APOA4 had increased expression in the Apoe-/- retina. In addition, there were changes in retinal abundance of proteins involved in proinflammatory and antiinflammatory responses, cellular cytoskeleton maintenance, vesicular traffic, and retinal iron homeostasis. The data obtained indicate that when APOE is absent, particles containing APOA1, APOA4, and APOJ still transport cholesterol in the intraretinal space, but these particles are not taken up by retinal cells. Therefore, cholesterol biosynthesis inside retinal cells increase, whereas metabolism to oxysterols decreases to prevent cells from cholesterol depletion. These and other compensatory changes underlie only a minor retinal phenotype in Apoe-/- mice.
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Affiliation(s)
- Aicha Saadane
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH
| | - Alexey Petrov
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH
| | - Natalia Mast
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH
| | - Nicole El-Darzi
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH
| | - Tung Dao
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH
| | - Ahab Alnemri
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ying Song
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Joshua L Dunaief
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Irina A Pikuleva
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH
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Keenan TD, Agrón E, Domalpally A, Clemons TE, van Asten F, Wong WT, Danis RG, Sadda S, Rosenfeld PJ, Klein ML, Ratnapriya R, Swaroop A, Ferris FL, Chew EY. Progression of Geographic Atrophy in Age-related Macular Degeneration: AREDS2 Report Number 16. Ophthalmology 2018; 125:1913-1928. [PMID: 30060980 DOI: 10.1016/j.ophtha.2018.05.028] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/25/2023] Open
Abstract
PURPOSE To analyze the prevalence, incidence, and clinical characteristics of eyes with geographic atrophy (GA) in age-related macular degeneration (AMD), including clinical and genetic factors affecting enlargement. DESIGN Prospective cohort study within a controlled clinical trial. PARTICIPANTS Age-Related Eye Disease Study 2 (AREDS2) participants, aged 50-85 years. METHODS Baseline and annual stereoscopic color fundus photographs were evaluated for GA presence and area. Analyses included GA prevalence and incidence rates, Kaplan-Meier rates, mixed-model regression, and multivariable analysis of the square root of GA, area adjusted for covariates, including clinical/imaging characteristics and genotype. MAIN OUTCOME MEASURES (1) Presence or development of GA; (2) change in the square root of GA area over time. RESULTS At baseline, 517 eyes (6.2%) of 411 participants (9.8%) had pre-existing GA (without neovascular AMD), with the following characteristics: 33% central, 67% noncentral; and the following configurations: 36% small, 26% solid/unifocal, 24% multifocal, 9% horseshoe/ring, and 6% indeterminate. Of the remaining 6530 eyes at risk, 1099 eyes (17.3%) of 883 participants developed incident GA without prior neovascular disease during mean follow-up of 4.4 years. The Kaplan-Meier rate of incident GA was 19% of eyes at 5 years. In eyes with incident GA, 4-year risk of subsequent neovascular AMD was 29%. In eyes with incident noncentral GA, 4-year risk of central involvement was 57%. GA enlargement rate (following square root transformation) was similar in eyes with pre-existing GA (0.29 mm/year; 95% confidence interval 0.27-0.30) and incident GA (0.28 mm/year; 0.27-0.30). In the combined group, GA enlargement was significantly faster with noncentrality, multifocality, intermediate baseline size, and bilateral GA (P < 0.0001 for interaction in each case) but not with AREDS2 treatment assignment (P = 0.33) or smoking status (P = 0.05). Enlargement was significantly faster with ARMS2 risk (P < 0.0001), C3 non-risk (P = 0.0002), and APOE non-risk (P = 0.001) genotypes. CONCLUSIONS Analyses of AREDS2 data on natural history of GA provide representative data on GA evolution and enlargement. GA enlargement, which was influenced by lesion features, was relentless, resulting in rapid central vision loss. The genetic variants associated with faster enlargement were partially distinct from those associated with risk of incident GA. These findings are relevant to further investigations of GA pathogenesis and clinical trial planning.
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Affiliation(s)
- Tiarnan D Keenan
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Elvira Agrón
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Amitha Domalpally
- Fundus Photographic Reading Center, The University of Wisconsin, Madison, Wisconsin
| | | | - Freekje van Asten
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wai T Wong
- Unit on Microglia, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Ronald G Danis
- Fundus Photographic Reading Center, The University of Wisconsin, Madison, Wisconsin
| | | | - Philip J Rosenfeld
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Michael L Klein
- Casey Eye Institute, Portland, Oregon; Devers Eye Clinic, Portland, Oregon
| | - Rinki Ratnapriya
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Frederick L Ferris
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Emily Y Chew
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland.
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Rudolf M, Mir Mohi Sefat A, Miura Y, Tura A, Raasch W, Ranjbar M, Grisanti S, Aherrahrou Z, Wagner A, Messinger JD, Garber DW, Anantharamaiah GM, Curcio CA. ApoA-I Mimetic Peptide 4F Reduces Age-Related Lipid Deposition in Murine Bruch's Membrane and Causes Its Structural Remodeling. Curr Eye Res 2017; 43:135-146. [PMID: 28972410 DOI: 10.1080/02713683.2017.1370118] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE Accumulation of lipoprotein-derived lipids including esterified and unesterified cholesterol in Bruch's membrane of human eyes is a major age-related change involved in initiating and sustaining soft drusen in age-related macular degeneration (AMD). The apolipoprotein (apo) A-I mimetic peptide 4F is a small anti-inflammatory and anti-atherogenic agent, and potent modifier of plasma membranes. We evaluated the effect of intravitreally-injected 4F on murine Bruch's membrane. METHODS We tested single intravitreal injections of 4F doses (0.6 µg, 1.2 µg, 2.4 µg, and placebo scrambled peptide) in ApoEnull mice ≥10 months of age. After 30 days, mice were euthanized. Eyes were processed for either direct immunofluorescence detection of esterified cholesterol (EC) in Bruch's membrane whole mounts via a perfringolysin O-based marker linked to green fluorescent protein or by transmission electron microscopic visualization of Bruch's membrane integrity. Fluorescein isothiocyanate-conjugated 4F was traced after injection. RESULTS All injected eyes showed a dose-dependent reduction of Bruch's membrane EC with a concomitant ultrastructural improvement compared to placebo treated eyes. At a 2.4 µg dose of 4F, EC was reduced on average by ~60% and Bruch's membrane returned to a regular pentalaminar structure and thickness. Tracer studies confirmed that injected 4F reached intraocular targets. CONCLUSION We demonstrated a highly effective pharmacological reduction of EC and restoration of Bruch's membrane ultrastructure. The apoA-I mimetic peptide 4F is a novel way to treat a critical AMD disease process and thus represents a new candidate for treating the underlying cause of AMD.
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Affiliation(s)
- Martin Rudolf
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany
| | | | - Yoko Miura
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany
| | - Aysegül Tura
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany
| | - Walter Raasch
- b Department of Experimental and Clinical Pharmacology and Toxicology , University of Lübeck , Lübeck , Germany
| | - Mahdy Ranjbar
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany.,c Laboratory for Angiogenesis & Ocular Cell Transplantation , University of Lübeck , Lübeck , Germany
| | | | - Zouhair Aherrahrou
- d Institute of Integrative and Experimental Genomics , University of Lübeck , Lübeck , Germany
| | - Anna Wagner
- a Department of Ophthalmology , University of Lübeck , Lübeck , Germany
| | - Jeffrey D Messinger
- e Department of Ophthalmology , University of Alabama at Birmingham , Birmingham , AL , USA
| | - David W Garber
- f Atherosclerosis Research Unit , University of Alabama at Birmingham , Birmingham , AL , USA
| | - G M Anantharamaiah
- f Atherosclerosis Research Unit , University of Alabama at Birmingham , Birmingham , AL , USA.,g Department of Medicine, Biochemistry and Molecular Genetics , University of Alabama at Birmingham , Birmingham , AL , USA
| | - Christine A Curcio
- e Department of Ophthalmology , University of Alabama at Birmingham , Birmingham , AL , USA
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10
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Neuroprotective effect against axonal damage-induced retinal ganglion cell death in apolipoprotein E-deficient mice through the suppression of kainate receptor signaling. Brain Res 2014; 1586:203-12. [PMID: 25160129 DOI: 10.1016/j.brainres.2014.08.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 08/18/2014] [Accepted: 08/18/2014] [Indexed: 11/22/2022]
Abstract
Apolipoprotein E (ApoE) plays important roles in the body, including a carrier of cholesterols, an anti-oxidant, and a ligand for the low-density lipoprotein receptors. In the nervous system, the presence of ApoE4 isoforms is associated with Alzheimer's disease. ApoE gene polymorphisms are also associated with glaucoma, but the function of ApoE in the retina remains unclear. In this study, we investigated the role of ApoE in axonal damage-induced RGC death. ApoE was detected in the astrocytes and Müller cells in the wild-type (WT) retina. RGC damage was induced in adult ApoE-deficient mice (male, 10-12 weeks old) through ocular hypertension (OH), optic nerve crush (NC), or by administering kainic acid (KA) intravitreally. The WT mice were treated with a glutamate receptor antagonist (MK801 or CNQX) 30 min before performing NC or left untreated. Seven days later, the retinas were flat mounted and Fluorogold-labeled RGCs were counted. We found that the RGCs in the ApoE-deficient mice were resistant to OH-induced RGC death and optic nerve degeneration 4 weeks after induction. In WT mice, NC effectively induced RGC death (control: 4085±331 cells/mm(2), NC: 1728±170 cells/mm(2)). CNQX, an inhibitor of KA receptors, suppressed this RGC death (3031±246 cells/mm(2)), but MK801, an inhibitor of NMDA receptors, did not (1769±212 cells/mm(2)). This indicated the involvement of KA receptor signaling in NC-induced RGC death. We found that NC- or KA-induced RGC death was significantly less in the ApoE-deficient mice than in the WT mice. These data suggest that the ApoE deficiency had a neuroprotective effect against axonal damage-induced RGC death by suppressing the KA receptor signaling.
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Janssen SF, Gorgels TG, Ramdas WD, Klaver CC, van Duijn CM, Jansonius NM, Bergen AA. The vast complexity of primary open angle glaucoma: Disease genes, risks, molecular mechanisms and pathobiology. Prog Retin Eye Res 2013; 37:31-67. [DOI: 10.1016/j.preteyeres.2013.09.001] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 07/26/2013] [Accepted: 09/03/2013] [Indexed: 12/21/2022]
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12
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Pfrieger FW, Ungerer N. Cholesterol metabolism in neurons and astrocytes. Prog Lipid Res 2011; 50:357-71. [PMID: 21741992 DOI: 10.1016/j.plipres.2011.06.002] [Citation(s) in RCA: 345] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 06/11/2011] [Accepted: 06/22/2011] [Indexed: 12/20/2022]
Abstract
Cells in the mammalian body must accurately maintain their content of cholesterol, which is an essential membrane component and precursor for vital signalling molecules. Outside the brain, cholesterol homeostasis is guaranteed by a lipoprotein shuttle between the liver, intestine and other organs via the blood circulation. Cells inside the brain are cut off from this circuit by the blood-brain barrier and must regulate their cholesterol content in a different manner. Here, we review how this is accomplished by neurons and astrocytes, two cell types of the central nervous system, whose cooperation is essential for normal brain development and function. The key observation is a remarkable cell-specific distribution of proteins that mediate different steps of cholesterol metabolism. This form of metabolic compartmentalization identifies astrocytes as net producers of cholesterol and neurons as consumers with unique means to prevent cholesterol overload. The idea that cholesterol turnover in neurons depends on close cooperation with astrocytes raises new questions that need to be addressed by new experimental approaches to monitor and manipulate cholesterol homeostasis in a cell-specific manner. We conclude that an understanding of cholesterol metabolism in the brain and its role in disease requires a close look at individual cell types.
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Affiliation(s)
- Frank W Pfrieger
- CNRS UPR 3212, University of Strasbourg, Institute of Cellular and Integrative Neurosciences (INCI), 67084 Strasbourg Cedex, France.
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Kishan AU, Modjtahedi BS, Martins EN, Modjtahedi SP, Morse LS. Lipids and age-related macular degeneration. Surv Ophthalmol 2011; 56:195-213. [PMID: 21439604 DOI: 10.1016/j.survophthal.2010.08.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 08/29/2010] [Accepted: 08/31/2010] [Indexed: 01/17/2023]
Abstract
Given the considerable public health burden imposed by age-related macular degeneration (AMD), much effort has been directed towards elucidating principles of pathogenesis in order to identify risk factors and develop preventive measures and treatments. Together with epidemiological evidence linking cardiovascular risk factors with AMD risk and basic science work examining the role of lipid metabolism in AMD, numerous human studies have assayed a potential relationship between dietary lipids and the development of AMD. We examine the evidence for a role for lipid metabolism in AMD, highlighting key basic biochemical principles, work in animal models, and relevant human studies. The topics of lipoprotein modulation and omega-3 fatty acid intake receive special attention from both a basic science and clinical study standpoint. The evidence suggests that consumption of omega-3 fatty acids, perhaps in concert with antioxidants, may constitute a rational preventative strategy against AMD development, though, absent an appropriately developed double-blind, randomized control trial, insufficient data exist to recommend implementation in the clinical setting at this time.
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Picard E, Houssier M, Bujold K, Sapieha P, Lubell W, Dorfman A, Racine J, Hardy P, Febbraio M, Lachapelle P, Ong H, Sennlaub F, Chemtob S. CD36 plays an important role in the clearance of oxLDL and associated age-dependent sub-retinal deposits. Aging (Albany NY) 2010; 2:981-9. [PMID: 21098885 PMCID: PMC3034186 DOI: 10.18632/aging.100218] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 11/07/2010] [Indexed: 12/02/2022]
Abstract
Age-related macular degeneration (AMD) represents the major cause of vision loss in industrialized nations. Laminar deposits in Bruch's membrane (BM) are among the first prominent histopathologic features, along with drusen formation, and have been found to contain oxidized lipids. Increases in concentrations of oxidized LDL (oxLDL) in plasma are observed with age and high fat high (HFHC) cholesterol diet. CD36 is the principal receptor implicated in uptake of oxLDL, and is expressed in the retinal pigment epithelium (RPE). We determined if CD36 participates in oxLDL uptake in RPE and correspondingly in clearance of sub-retinal deposits. Uptake of oxLDL by RPEin vitro and in vivo was CD36-dependent. CD36 deficiency in mice resulted in age-associated accumulation of oxLDL and sub-retinal BM thickening, despite fed a regular diet. Conversely, treatment of HFHC-fed ApoE null mice with a CD36 agonist, EP80317 (300 μg/kg/day), markedly diminished thickening of BM, and partially preserved (in part) photoreceptor function. In conclusion, our data uncover a new role for CD36 in the clearance of oxidized lipids from BM and in the prevention of age-dependent sub-retinal laminar deposits.
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Affiliation(s)
- Emilie Picard
- Departments of Pediatrics, Ophthalmology, and Pharmacology, Research Center, Hospitals Ste. Justine and Maisonneuve-Rosemont, Université de Montréal, Montreal, Quebec, Canada
| | - Marianne Houssier
- Inserm, U872, Paris, F-75006 France
- Centre de Recherche des Cordeliers, Université Pierre et Marie Curie - Paris 6, UMR S 872, Paris, F-75006 France
- Université Paris Descartes, UMR S 872, Paris, F-75006 France
| | - Kim Bujold
- Faculty of Pharmacy, University de Montreal, Montreal, Quebec, Canada
| | - Przemyslaw Sapieha
- Departments of Pediatrics, Ophthalmology, and Pharmacology, Research Center, Hospitals Ste. Justine and Maisonneuve-Rosemont, Université de Montréal, Montreal, Quebec, Canada
| | - William Lubell
- Departments of Chemistry, University de Montreal, Montreal, Quebec, Canada
| | - Allison Dorfman
- Departments of Ophthalmology, McGill University, Montreal, Quebec, Canada
| | - Julie Racine
- Departments of Ophthalmology, McGill University, Montreal, Quebec, Canada
| | - Pierre Hardy
- Departments of Pediatrics, Ophthalmology, and Pharmacology, Research Center, Hospitals Ste. Justine and Maisonneuve-Rosemont, Université de Montréal, Montreal, Quebec, Canada
| | - Maria Febbraio
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 4412, USA
| | - Pierre Lachapelle
- Departments of Ophthalmology, McGill University, Montreal, Quebec, Canada
| | - Huy Ong
- Faculty of Pharmacy, University de Montreal, Montreal, Quebec, Canada
| | - Florian Sennlaub
- Inserm, U872, Paris, F-75006 France
- Centre de Recherche des Cordeliers, Université Pierre et Marie Curie - Paris 6, UMR S 872, Paris, F-75006 France
- Université Paris Descartes, UMR S 872, Paris, F-75006 France
- APHP, Département d'Ophthalmologie Hôtel Dieu, Paris, France
| | - Sylvain Chemtob
- Departments of Pediatrics, Ophthalmology, and Pharmacology, Research Center, Hospitals Ste. Justine and Maisonneuve-Rosemont, Université de Montréal, Montreal, Quebec, Canada
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Luthra S, Dong J, Gramajo AL, Chwa M, Kim DW, Neekhra A, Kuppermann BD, Kenney MC. 7-Ketocholesterol activates caspases-3/7, -8, and -12 in human microvascular endothelial cells in vitro. Microvasc Res 2008; 75:343-50. [PMID: 18068200 DOI: 10.1016/j.mvr.2007.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 09/18/2007] [Accepted: 10/19/2007] [Indexed: 11/30/2022]
Abstract
7-Ketocholesterol (7kCh) is a major oxysterol found associated with vascular diseases. Human microvascular endothelial cells (HMVECs) were cultured with different concentrations of 7kCh with and without inhibitors. Cell viabilities and caspase activities were assessed. 7kCh caused loss of cell viability in a dose-dependent manner. Caspases-8, -12, and -3/7 but not caspase-9 were activated by 7kCh treatment. The 7kCh-induced caspase-8 activity was blocked partially by pre-treatment with z-VAD-fmk and z-IETD-fmk, a caspase-8 inhibitor. However, pre-treatment with z-ATAD-fmk, a caspase-12 inhibitor, followed by 7kCh exposure lead to significantly increased caspase-8 activity. This suggests that caspase-8 and caspase-12 pathways have unique inhibition patterns and that caspase-12 is likely not upstream and feeding into caspase-8 but the pathways may function in parallel to each other. Caspase-3/7 activation was inhibited partially by low density lipoprotein (LDL), high density lipoprotein (HDL), z-VAD-fmk (pan-caspase inhibitor), and low doses (0.01 and 0.001 microM) of the cholesterol lowering drug, simvastatin. However, only LDL partially protected against 7kCh-induced loss of cell viability suggesting that caspase-independent pathways also contributed to the cell loss and that protection from oxysterol damage may require inhibition of multiple pathways. Moreover, our data suggest that oxysterols such as 7kCh can damage HMVECs cells in part via caspase-dependent apoptosis and may play a role in vascular and retinal diseases.
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Bretillon L, Diczfalusy U, Björkhem I, Maire MA, Martine L, Joffre C, Acar N, Bron A, Creuzot-Garcher C. Cholesterol-24S-hydroxylase (CYP46A1) is specifically expressed in neurons of the neural retina. Curr Eye Res 2007; 32:361-6. [PMID: 17453958 DOI: 10.1080/02713680701231857] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Increasing biological findings argue for the importance of cholesterol-24S-hydroxylase (CYP46A1) in cholesterol homeostasis in cerebral structures. Based on the similarity between the brain and the neural retina, the aim of the current study was to evaluate the expression of CYP46A1 in the mammalian retina. RT-PCR analysis of CYP46A1 in bovine samples revealed the highest expression in the neural retina. The retinal pigment epithelium expressed CYP46A1 gene at a low level while the ciliary body showed no expression. Immunohistochemical evaluation of the posterior pole of rat retina showed that the protein is specifically expressed in neurons, whereas cone-rods photoreceptors were negative for CYP46A1 staining. The metabolite produced by CYP46A1, 24S-hydroxycholesterol, was almost exclusively found in neural retina, the concentration therein being more than 10-fold higher than in the retinal pigment epithelium or the ciliary body. The results of the current study are consistent with our primary hypothesis: the neural retina specifically expresses cholesterol-24S-hydroxylase, a metabolizing enzyme responsible for the removal of cholesterol in neurons. Based on the link between cholesterol-24S-hydroxylase, 24S-hydroxycholesterol, and neurologic disorders, CYP46A1 may be a valuable gene candidate for retinal pathologies like age-related macular degeneration or glaucomas, and 24S-hydroxycholesterol may be involved in the onset of the degenerative processes in these diseases.
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Affiliation(s)
- Lionel Bretillon
- Eye and Nutrition Research Group, UMR 1129 FLAVIC, INRA, ENESAD, University of Burgundy, Dijon, France, and Department of Laboratory Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden.
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Puskás LG, Bereczki E, Sántha M, Vigh L, Csanádi G, Spener F, Ferdinandy P, Onochy A, Kitajka K. Cholesterol and cholesterol plus DHA diet-induced gene expression and fatty acid changes in mouse eye and brain. Biochimie 2005; 86:817-24. [PMID: 15589691 DOI: 10.1016/j.biochi.2004.10.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Accepted: 10/08/2004] [Indexed: 01/10/2023]
Abstract
Both cholesterol and polyunsaturated fatty acid (PUFA) metabolism play an important role in retinal and brain development and function. Dietary intake of cholesterol is accompanied with higher risk of heart disease and was suggested to have a role in the pathogenesis of Alzheimer's disease, while dietary PUFAs were reported to act in an opposite way. The same phenomena could be seen in case of inflammation. These effects are mainly realized through gene expression changes. In the present study, the effects of dietary cholesterol and the combination of cholesterol and fish oil were analyzed on the modulation of fatty acid composition and gene expression in the brain and in the eye. At the transcription level, specific changes could be detected in both tissues among transcription factor genes coding for sterol regulatory element binding proteins, retinoid X receptors and peroxisome proliferator-activated receptors, and different fatty acid binding protein genes by using quantitative real-time PCR. In the eye, cholesterol diet attenuated the positive effects of fish oil on inflammatory gene expression as the combined diet resulted in increased RNAm level of phospholipase A-2, inducible nitric oxide synthase, TNF-alpha, COX-1, COX-2 and cytokine, ICAM-1. This induction was absent in the brain. Complex changes could be also recorded in the fatty acid composition of lipids extracted from eye and brain tissue due to the dietary intervention. One of the most interesting changes was the reduced level of docosahexaenoic acid by cholesterol in the eye. Our results on fatty acid composition and gene expression changes may open up new alleys in understanding the complex roles of cholesterol and PUFAs in normal and pathological visual and brain function.
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Affiliation(s)
- László G Puskás
- Laboratory of Functional Genomics, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged, Hungary
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Lu CK, Chen SJ, Niu DM, Tsai CC, Lee FL, Hsu WM. Electrophysiological changes in lipaemia retinalis. Am J Ophthalmol 2005; 139:1142-5. [PMID: 15953465 DOI: 10.1016/j.ajo.2004.12.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Accepted: 12/09/2004] [Indexed: 11/16/2022]
Abstract
PURPOSE To report the electrophysiologic findings in a patient with lipaemia retinalis. DESIGN Observational case report. METHODS An 11-year-old girl with diabetes had hyperlipidemia and presented for ophthalmologic consultation. Fundus examinations revealed milky discoloration of retinal vessels in both eyes. Laboratory testing disclosed hyperglycemia and markedly elevated level of triglycerides and cholesterol. Although the visual acuity was not affected, the electroretinograms showed decrease amplitudes of a- and b-wave in both cone and rod responses. RESULTS After correction of blood sugar and lipids with insulin and diet control, the lipaemia retinalis resolved, and the impaired ERG response reversed within 1 week. CONCLUSIONS Lipaemia retinalis usually resolves rapidly without visual impairment after correction of hyperlipidemia. The reversible deficits of electroretinogram response in lipaemia retinalis are reported for the first time. High level of triglycerides or cholesterol or both may impair retinal function. The mechanism of an impaired electroretinogram remained speculative.
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Affiliation(s)
- Chao-Kung Lu
- Department of Ophthalmology, Taipei Veterans General Hospital, #201 Section 2 Shih-Pai Road, Taipei 112, Taiwan
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