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Fujita A, Amari T, Ueda K, Azuma K, Inoue T, Komatsu K, Yamamoto M, Aoki N, Yamanari M, Sugiyama S, Aihara M, Kato S, Obata R. Three-Dimensional Distribution Of Fundus Depolarization and Associating Factors Measured Using Polarization-Sensitive Optical Coherence Tomography. Transl Vis Sci Technol 2021; 10:30. [PMID: 34003915 PMCID: PMC7900852 DOI: 10.1167/tvst.10.2.30] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose To investigate the three-dimensional distribution and associating demographic factors of depolarization, using polarization-sensitive optical coherence tomography (PS-OCT), to evaluate melanin pigmentation in the retinal pigment epithelium (RPE) and choroid in healthy eyes. Methods In total, 39 unaffected healthy eyes of 39 subjects were examined using a PS-OCT clinical prototype. The degree of depolarization, expressed as the polarimetric entropy, was assessed in the RPE, the superficial and the total choroid layer, especially in the center, the inner, or the outer areas centered at the fovea. The values and their association with the demographic data were analyzed. Near-infrared fundus autofluorescence (NIRAF) was also used, in the same manner, for the comparison. Twenty-eight of 39 eyes were measured twice to evaluate intrasession repeatability. Results Both the polarimetric entropy in the RPE and the gray level in NIRAF, decreased from the center to the periphery (P < 0.001). The polarimetric entropy in the RPE was significantly associated with age in each area (P ≤ 0.001). In the RPE and the superficial choroid, the polarimetric entropy was negatively associated with axial length in each area (P ≤ 0.002). The intraclass correlation coefficient of the polarimetric entropy in the same session was excellent in each area of the RPE, superficial choroid, or total choroid layer (0.94–0.98). Conclusions The distribution of fundus melanin pigment-related depolarization was evaluated using PS-OCT. The depolarization was associated with the subjects’ demographic data, such as age or axial length. Translational Relevance The presented information in healthy eyes provides an essential basis for the investigation into a variety of chorioretinal pathologies.
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Affiliation(s)
- Asahi Fujita
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan.,Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan
| | - Tatsuaki Amari
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan.,Eguchi Eye Hospital, Hakodate, Japan
| | - Kohei Ueda
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Keiko Azuma
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Tatsuya Inoue
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan.,Department of Ophthalmology, Yokohama City University Medical Center, Yokohama, Japan
| | - Kayoko Komatsu
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Motoshi Yamamoto
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | | | | | | | - Makoto Aihara
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Satoshi Kato
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
| | - Ryo Obata
- Department of Ophthalmology, The University of Tokyo Hospital, Tokyo, Japan
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Fetal oxidative stress, micronutrient deficiency and risk of retinopathy of prematurity: a nested case-control study. Eur J Pediatr 2021; 180:1487-1496. [PMID: 33410943 DOI: 10.1007/s00431-020-03896-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/21/2020] [Accepted: 11/24/2020] [Indexed: 10/22/2022]
Abstract
UNLABELLED We hypothesized that fetal oxidative stress and micronutrient deficiencies contribute to higher incidence of retinopathy of prematurity (ROP) in developing countries. In a nested case-control study, preterm infants (< 37 weeks, < 1700 g) were included at birth and followed until 40 weeks post-menstrual age (PMA). Maternal, cord, and neonatal serum/plasma samples at 40 weeks PMA were frozen. Samples of "cases" with ROP and gestational age (GA) and birth weight-matched "controls" with no ROP (in 1:4 ratio) were thawed and analyzed. PRIMARY OUTCOME MDA concentration in cord plasma. SECONDARY OUTCOMES MDA in maternal and 40-week PMA plasma; copper, zinc, and vitamin A in maternal, cord, and 40-week PMA samples. Thirty-eight cases and 151 controls had a mean (SD) GA of 29.5 (1) and 29.9 (1) weeks respectively. Following were associated with ROP: higher MDA concentration in cord and 40-week PMA samples; lower copper and zinc in maternal serum; lower zinc and vitamin A in cord sample (all p < 0.05). MDA [adjusted OR (aOR) = 4.13 (95% CI 1.83-9.27)] and vitamin A [aOR = 0.09 (95% CI 0.02-0.4)] concentration in cord plasma and weight gain (g/kg/week) [aOR = 0.97 (0.95-0.99)] independently predicted ROP. CONCLUSION Increased oxidative stress and deficiency of micronutrients from fetal life were associated with ROP. CLINICAL TRIAL REGISTRATION Clinical Trials Registry of India CTRI/REF/2014/12/008174. What is Known: • In developing countries, there is a higher incidence of retinopathy of prematurity (ROP), but micronutrient deficiencies have not been adequately investigated as risk factors. • Few observational studies have shown an association between ROP and postnatal increase in malondialdehyde (MDA) levels and deficiencies of antioxidant vitamins and minerals, but none in cord blood. What is New: • High MDA, low zinc, and low vitamin A levels in cord blood and low copper and zinc levels in maternal blood are associated with the development of ROP. • On multivariable analysis, high cord blood MDA and low cord blood vitamin A are independent predictors of ROP.
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Gilbert R, Peto T, Lengyel I, Emri E. Zinc Nutrition and Inflammation in the Aging Retina. Mol Nutr Food Res 2019; 63:e1801049. [PMID: 31148351 DOI: 10.1002/mnfr.201801049] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 04/18/2019] [Indexed: 12/16/2022]
Abstract
Zinc is an essential nutrient for human health. It plays key roles in maintaining protein structure and stability, serves as catalytic factor for many enzymes, and regulates diverse fundamental cellular processes. Zinc is important in affecting signal transduction and, in particular, in the development and integrity of the immune system, where it affects both innate and adaptive immune responses. The eye, especially the retina-choroid complex, has an unusually high concentration of zinc compared to other tissues. The highest amount of zinc is concentrated in the retinal pigment epithelium (RPE) (RPE-choroid, 292 ± 98.5 µg g-1 dry tissue), followed by the retina (123 ± 62.2 µg g-1 dry tissue). The interplay between zinc and inflammation has been explored in other parts of the body but, so far, has not been extensively researched in the eye. Several lines of evidence suggest that ocular zinc concentration decreases with age, especially in the context of age-related disease. Thus, a hypothesis that retinal function could be modulated by zinc nutrition is proposed, and subsequently trialled clinically. In this review, the distribution and the potential role of zinc in the retina-choroid complex is outlined, especially in relation to inflammation and immunity, and the clinical studies to date are summarized.
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Affiliation(s)
- Rosie Gilbert
- Moorfields Eye Hospital NHS Foundation Trust, City Road, London, EC1V 2PD, UK.,UCL Institute of Ophthalmology, Bath Street, London, EC1V 2EL, UK
| | - Tunde Peto
- School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Ireland
| | - Imre Lengyel
- UCL Institute of Ophthalmology, Bath Street, London, EC1V 2EL, UK.,School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Ireland
| | - Eszter Emri
- School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Ireland
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Pao PJ, Emri E, Abdirahman SB, Soorma T, Zeng HH, Hauck SM, Thompson RB, Lengyel I. The effects of zinc supplementation on primary human retinal pigment epithelium. J Trace Elem Med Biol 2018. [PMID: 29523386 DOI: 10.1016/j.jtemb.2018.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Population-based and interventional studies have shown that elevated zinc levels can reduce the progression to advanced age-related macular degeneration. The objective of this study was to assess whether elevated extracellular zinc has a direct effect on retinal pigment epithelial cells (RPE), by examining the phenotype and molecular characteristics of increased extracellular zinc on human primary RPE cells. Monolayers of human foetal primary RPE cells were grown on culture inserts and maintained in medium supplemented with increasing total concentrations of zinc (0, 75, 100, 125 and 150 μM) for up to 4 weeks. Changes in cell viability and differentiation as well as expression and secretion of proteins were investigated. RPE cells developed a confluent monolayer with cobblestone morphology and transepithelial resistance (TER) >200 Ω*cm2 within 4 weeks. There was a zinc concentration-dependent increase in TER and pigmentation, with the largest effects being achieved by the addition of 125 μM zinc to the culture medium, corresponding to 3.4 nM available (free) zinc levels. The cells responded to addition of zinc by significantly increasing the expression of Retinoid Isomerohydrolase (RPE65) gene; cell pigmentation; Premelanosome Protein (PMEL17) immunoreactivity; and secretion of proteins including Apolipoprotein E (APOE), Complement Factor H (CFH), and High-Temperature Requirement A Serine Peptidase 1 (HTRA1) without an effect on cell viability. This study shows that elevated extracellular zinc levels have a significant and direct effect on differentiation and function of the RPE cells in culture, which may explain, at least in part, the positive effects seen in clinical settings. The results also highlight that determining and controlling of available, as opposed to total added, zinc will be essential to be able to compare results obtained in different laboratories.
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Affiliation(s)
- Po-Jung Pao
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
| | - Eszter Emri
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, United Kingdom.
| | - Safiya Bishar Abdirahman
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom.
| | - Talha Soorma
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom.
| | - Hui-Hui Zeng
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, United States.
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health(GmbH), Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
| | - Richard B Thompson
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, United States.
| | - Imre Lengyel
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, United Kingdom.
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5
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Karthikeyan B, Arun A, Harini L, Sundar K, Kathiresan T. Role of ZnS Nanoparticles on Endoplasmic Reticulum Stress-mediated Apoptosis in Retinal Pigment Epithelial Cells. Biol Trace Elem Res 2016; 170:390-400. [PMID: 26329999 DOI: 10.1007/s12011-015-0493-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/24/2015] [Indexed: 01/22/2023]
Abstract
Age-related macular degeneration (AMD) is the leading cause for irreversible visual impairment affecting 30-50 million individuals every year. Oxidative stress and endoplasmic reticulum stress have been identified as crucial factors for the pathogenesis of AMD. Current treatments do not focus on underlying stimuli responsible for the disease like AMD. Zinc is an important trace metal in retina and its deficiency leads to AMD. Recent studies on zinc sulphide nanoparticles (ZnS-NPs) are gaining attention in the field of physical and biological research. In this present study, in investigating the role of ZnS-NPs on hydrogen peroxide and thapsigargin-treated primary mice retinal pigment epithelial (MRPE) cells, we synthesized ZnS-NPs and characterized using atomic force microscope (AFM) and SEM-EDX. The ZnS-NPs abrogate the primary MRPE cell death through inhibition of oxidative stress-induced reactive oxygen species production and cell permeability. Oxidant molecules hydrogen peroxide and thapsigargin alter unfolded protein response such as glucose-regulated protein 78 (GRP78) and C/EBP homology protein (CHOP) expressions, whereas ZnS-NPs-pre-treated primary MRPE cells downregulated the overexpression of such proteins. The expressions of apoptotic proteins caspase 12 and cleaved caspase 9 and caspase 3 were also significantly controlled in ZnS-NPs-treated primary MRPE cells when comparing with thapsigargin- and hydrogen peroxide-treated cells. From these results, ZnS-NPs stabilize reactive oxygen species elevation, when subjected to hydrogen peroxide- and thapsigargin-mediated oxidant injury and helps in maintaining normal homeostasis through regulating endoplasmic reticulum (ER) stress response proteins which is the lead cause for apoptosis-mediated pathogenesis of AMD.
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Affiliation(s)
- Bose Karthikeyan
- Department of Biotechnology, Kalasalingam University, Krishnankoil, Tamil Nadu, -626 126, India
| | - Arumugaperumal Arun
- Department of Biotechnology, Kalasalingam University, Krishnankoil, Tamil Nadu, -626 126, India
| | | | - Krishnan Sundar
- Department of Biotechnology, Kalasalingam University, Krishnankoil, Tamil Nadu, -626 126, India
- International Research Centre, Kalasalingam University, Krishnankoil, Tamil Nadu, -626 126, India
| | - Thandavarayan Kathiresan
- Department of Biotechnology, Kalasalingam University, Krishnankoil, Tamil Nadu, -626 126, India.
- International Research Centre, Kalasalingam University, Krishnankoil, Tamil Nadu, -626 126, India.
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6
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Ugarte M, Osborne NN. Recent advances in the understanding of the role of zinc in ocular tissues. Metallomics 2014; 6:189-200. [DOI: 10.1039/c3mt00291h] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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7
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Ugarte M, Osborne NN, Brown LA, Bishop PN. Iron, zinc, and copper in retinal physiology and disease. Surv Ophthalmol 2013; 58:585-609. [DOI: 10.1016/j.survophthal.2012.12.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 12/09/2012] [Accepted: 12/11/2012] [Indexed: 12/26/2022]
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8
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Biesemeier A, Julien S, Kokkinou D, Schraermeyer U, Eibl O. A low zinc diet leads to loss of Zn in melanosomes of the RPE but not in melanosomes of the choroidal melanocytes. Metallomics 2012; 4:323-32. [DOI: 10.1039/c2mt00187j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Julien S, Biesemeier A, Kokkinou D, Eibl O, Schraermeyer U. Zinc deficiency leads to lipofuscin accumulation in the retinal pigment epithelium of pigmented rats. PLoS One 2011; 6:e29245. [PMID: 22216222 PMCID: PMC3245262 DOI: 10.1371/journal.pone.0029245] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 11/23/2011] [Indexed: 11/19/2022] Open
Abstract
Background Age-related macular degeneration (AMD) is associated with lipofuscin accumulation whereas the content of melanosomes decreases. Melanosomes are the main storage of zinc in the pigmented tissues. Since the elderly population, as the most affected group for AMD, is prone to zinc deficit, we investigated the chemical and ultrastructural effects of zinc deficiency in pigmented rat eyes after a six-month zinc penury diet. Methodology/Principal Findings Adult Long Evans (LE) rats were investigated. The control animals were fed with a normal alimentation whereas the zinc-deficiency rats (ZD-LE) were fed with a zinc deficient diet for six months. Quantitative Energy Dispersive X-ray (EDX) microanalysis yielded the zinc mole fractions of melanosomes in the retinal pigment epithelium (RPE). The lateral resolution of the analysis was 100 nm. The zinc mole fractions of melanosomes were significantly smaller in the RPE of ZD-LE rats as compared to the LE control rats. Light, fluorescence and electron microscopy, as well as immunohistochemistry were performed. The numbers of lipofuscin granules in the RPE and of infiltrated cells (Ø>3 µm) found in the choroid were quantified. The number of lipofuscin granules significantly increased in ZD-LE as compared to control rats. Infiltrated cells bigger than 3 µm were only detected in the choroid of ZD-LE animals. Moreover, the thickness of the Bruch's membrane of ZD-LE rats varied between 0.4–3 µm and thin, rangy ED1 positive macrophages were found attached at these sites of Bruch's membrane or even inside it. Conclusions/Significance In pigmented rats, zinc deficiency yielded an accumulation of lipofuscin in the RPE and of large pigmented macrophages in the choroids as well as the appearance of thin, rangy macrophages at Bruch's membrane. Moreover, we showed that a zinc diet reduced the zinc mole fraction of melanosomes in the RPE and modulated the thickness of the Bruch's membrane.
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Affiliation(s)
- Sylvie Julien
- Section of Experimental Vitreoretinal Surgery, Centre of Ophthalmology, Institute for Ophthalmic Research, Tuebingen, Germany
| | - Antje Biesemeier
- Section of Experimental Vitreoretinal Surgery, Centre of Ophthalmology, Institute for Ophthalmic Research, Tuebingen, Germany
| | - Despina Kokkinou
- Section of Experimental Vitreoretinal Surgery, Centre of Ophthalmology, Institute for Ophthalmic Research, Tuebingen, Germany
| | - Oliver Eibl
- Institute of Applied Physics, Eberhard Karls University of Tuebingen, Tuebingen, Germany
| | - Ulrich Schraermeyer
- Section of Experimental Vitreoretinal Surgery, Centre of Ophthalmology, Institute for Ophthalmic Research, Tuebingen, Germany
- * E-mail:
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10
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ZIP2 and ZIP4 mediate age-related zinc fluxes across the retinal pigment epithelium. J Mol Neurosci 2011; 46:122-37. [PMID: 21603979 DOI: 10.1007/s12031-011-9536-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 04/28/2011] [Indexed: 01/24/2023]
Abstract
Decreases in systemic and cellular levels of zinc (Zn(2+)) during normal aging correlate with several age-related pathologies including age-related macular degeneration. Zn(2+) homeostasis in tissues is not only dependent on dietary intake but also on optimal expression and function of its influx (ZIP) and efflux (ZnT) transporters. We recently showed that many of the Zn(2+) transporters are expressed by the retinal pigment epithelial (RPE) cells. In this study, we present evidence that RPE cells contain less endogenous Zn(2+) with increased aging and transport this ion vectorially with greater transport from the basal to apical direction. Expression of two Zn(2+) influx transporters, ZIP2 and ZIP4, is reduced as a function of RPE age. Gene silencing of ZIP2 and ZIP4 in RPE cells from young donors or their overexpression in cells from older donors confirms that these two transporters are essential in controlling Zn(2+) influx and sequestration in RPE cells. Both transporters are distributed on the basal surface of the RPE where they are likely to control Zn(2+) homeostasis in the outer retina.
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11
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Biesemeier A, Schraermeyer U, Eibl O. Quantitative chemical analysis of ocular melanosomes in stained and non-stained tissues. Micron 2011; 42:461-70. [PMID: 21330141 DOI: 10.1016/j.micron.2011.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 01/17/2011] [Accepted: 01/19/2011] [Indexed: 11/30/2022]
Abstract
Energy-filtered Analytical Electron Microscopy (AEM) was used to image the ultrastructure and determine quantitatively the chemical composition of rat melanosomes of the choroid and the Retinal Pigment Epithelium (RPE). For the first time, the effect of staining in elemental analysis of melanosomes was investigated. Detection limits and accuracies of the applied methods were determined. Compared to previous work applying only quantitative Energy Dispersive X-ray microanalysis (EDX) in the TEM (Eibl, O., et al., 2006. Micron 37, 262), here we present a combined quantitative EDX and Electron Energy Loss Spectroscopy (EELS) analysis, including N. This yields the fraction of eumelanin and pheomelanin in melanosomes by the S/N mole fraction ratio. Melanosomes of the sepia ink sac, used as eumelanin standard, showed an S/N mole fraction ratio of <0.004. Thus, they consist primarily of eumelanin as reported by degradation analysis. In contrast, melanosomes of the rats contained mixed melanin with significant amounts of pheomelanin (S/N 0.02) in the RPE and the choroid. Consistent with the previous publication, it was shown that oxygen mole fractions are especially large in melanosomes (7-10 at.%) compared to other cell compartments, e.g. 2-4 at.% oxygen in the cytoplasm. In the melanosomes of non-stained tissue, the oxygen mole fraction clearly correlated with the Ca mole fraction. EDX spectra used for quantitative analysis had about 15,000 net counts under the oxygen peak, which is necessary to obtain (i) a small statistical error for oxygen and (ii) optimum minimum detectable mole fractions for S, Ca and transition metals. The precise determination of the oxygen mole fraction in melanosomes is important for understanding metabolism. Therefore, a detailed analysis was carried out on the possible errors affecting quantification. While O, S, and N mole fractions yielded similar results in stained and non-stained ocular melanosomes of rats, transition metals can only be determined reliably in non-stained tissues. High-precision EDX analysis of melanosomes yielded minimum detectable mole fractions of less than 0.04 at.% for Cu and Zn, these elements were present in melanosomes with mole fractions of about 0.3 at.% and 0.1at.%, respectively. Zn is of great importance for metabolism and for age related macular degeneration. Its mole fraction in melanosomes of rats is large enough to be detected and to be quantitatively analyzed by EDX spectroscopy. Ultrastructural information can now be correlated to the elemental composition. This is important to better understand the physical and chemical properties of melanosomal metabolism and turnover.
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Affiliation(s)
- Antje Biesemeier
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
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12
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KELLNER ULRICH, KELLNER SIMONE, WEINITZ SILKE. FUNDUS AUTOFLUORESCENCE (488 NM) AND NEAR-INFRARED AUTOFLUORESCENCE (787 NM) VISUALIZE DIFFERENT RETINAL PIGMENT EPITHELIUM ALTERATIONS IN PATIENTS WITH AGE-RELATED MACULAR DEGENERATION. Retina 2010; 30:6-15. [PMID: 20066766 DOI: 10.1097/iae.0b013e3181b8348b] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Hirakawa M, Tanaka M, Tanaka Y, Okubo A, Koriyama C, Tsuji M, Akiba S, Miyamoto K, Hillebrand G, Yamashita T, Sakamoto T. Age-related maculopathy and sunlight exposure evaluated by objective measurement. Br J Ophthalmol 2008; 92:630-4. [PMID: 18441173 PMCID: PMC2569146 DOI: 10.1136/bjo.2007.130575] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aim: To study the relationship between age-related maculopathy (ARM) and exposure to sunlight using an objective method. Methods: In a case–control study of Japanese men aged ⩾50 years (67 controls without ophthalmic disease and 148 with ARM), those with ARM were separated into groups of early (n = 75) and late (n = 73) ARM. Facial wrinkle length and area of hyperpigmentation, which are considered to be associated with exposure to sun, were measured using imaging with computer-based image analysis. Skin tone was also measured on the upper inner arm, which is not exposed to sun. Early and late ARM association with skin measurements was then evaluated. Results: Significantly more facial wrinkling (p = 0.047, odds ratio 3.8; 95% CI 1.01 to 13.97) and less facial hyperpigmentation (p = 0.035, odds ratio 0.3; 95% CI 0.08 to 0.92) was present in late ARM cases. The relationship between skin tone and ARM risk was not statistically significant. Conclusions: This objective method showed that lifetime exposure to sunlight is an important factor in the progression of late ARM. An individual’s reaction to sunlight exposure may have a role in ARM progression in addition to total lifetime exposure to sunlight.
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Affiliation(s)
- M Hirakawa
- Department of Ophthalmology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan
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14
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Biesemeier A, Kokkinou D, Julien S, Heiduschka P, Berneburg M, Bartz-Schmidt KU, Schraermeyer U. UV-A induced oxidative stress is more prominent in naturally pigmented aged human RPE cells compared to non-pigmented human RPE cells independent of zinc treatment. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2007; 90:113-20. [PMID: 18203614 DOI: 10.1016/j.jphotobiol.2007.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 11/23/2007] [Accepted: 11/23/2007] [Indexed: 11/29/2022]
Abstract
To investigate the effects of zinc supplementation on human amelanotic (ARPE-19) and native pigmented retinal pigment epithelial cells (hRPE) under normal light conditions and after ultraviolet A light exposure. hRPE cells, containing both melanin and lipofuscin granules, were prepared from human donor eyes of 60-70 year old patients. Cells of the amelanotic ARPE-19 cell line and pigmented hRPE cells were treated with zinc chloride and subjected to oxidative stress by UV-A irradiation. Intracellular H(2)O(2) formation was measured using a fluorescence oxidation assay. Additionally, apoptosis and viability assays were performed. Control cells were treated identically except for irradiation and zinc supplementation. Under normal light conditions, zinc treated hRPE cells produced less H(2)O(2) than unsupplemented hRPE cells. Viability and apoptosis events did not change. After UV-A irradiation, ARPE and hRPE cells were greatly impaired in all tests performed compared to the non-irradiated controls. No differences were found after zinc supplementation. hRPE cells showed a higher apoptosis and mortality rate than non-pigmented cells when stressed by UV-A light. ARPE cells never showed any zinc related effects. In contrast, without irradiation, zinc supplementation reduced H(2)O(2) production in pigmented hRPE cells slightly. We did not find any zinc effect in irradiated hRPE cells. After UV light exposure, pigmented cells showed a higher apoptosis and mortality than cells lacking any pigmentation. We conclude that cells with pigmentation consisting of melanin and lipofuscin granules have more prooxidative than antioxidative capacity when stressed by UV light exposure compared to cells lacking any pigmentation.
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Affiliation(s)
- Antje Biesemeier
- Section of Experimental Vitreoretinal Surgery, University Eye Hospital Tuebingen, Schleichstr. 12/1, 72076 Tuebingen, Germany.
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