151
|
Taillard J, Capelli A, Sagaspe P, Anund A, Akerstedt T, Philip P. In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial. PLoS One 2012; 7:e46750. [PMID: 23094031 PMCID: PMC3477137 DOI: 10.1371/journal.pone.0046750] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 09/04/2012] [Indexed: 11/18/2022] Open
Abstract
UNLABELLED Prolonged wakefulness greatly decreases nocturnal driving performance. The development of in-car countermeasures is a future challenge to prevent sleep-related accidents. The aim of this study is to determine whether continuous exposure to monochromatic light in the short wavelengths (blue light), placed on the dashboard, improves night-time driving performance. In this randomized, double-blind, placebo-controlled, cross-over study, 48 healthy male participants (aged 20-50 years) drove 400 km (250 miles) on motorway during night-time. They randomly and consecutively received either continuous blue light exposure (GOLite, Philips, 468 nm) during driving or 2*200 mg of caffeine or placebo of caffeine before and during the break. Treatments were separated by at least 1 week. The outcomes were number of inappropriate line crossings (ILC) and mean standard deviation of the lateral position (SDLP). Eight participants (17%) complained about dazzle during blue light exposure and were removed from the analysis. Results from the 40 remaining participants (mean age ± SD: 32.9±11.1) showed that countermeasures reduced the number of inappropriate line crossings (ILC) (F(2,91.11) = 6.64; p<0.05). Indeed, ILC were lower with coffee (12.51 [95% CI, 5.86 to 19.66], p = 0.001) and blue light (14.58 [CI, 8.75 to 22.58], p = 0.003) than with placebo (26.42 [CI, 19.90 to 33.71]). Similar results were found for SDLP. Treatments did not modify the quality, quantity and timing of 3 subsequent nocturnal sleep episodes. Despite a lesser tolerance, a non-inferior efficacy of continuous nocturnal blue light exposure compared with caffeine suggests that this in-car countermeasure, used occasionally, could be used to fight nocturnal sleepiness at the wheel in blue light-tolerant drivers, whatever their age. More studies are needed to determine the reproducibility of data and to verify if it can be generalized to women. TRIAL REGISTRATION ClinicalTrials.gov NCT01070004.
Collapse
Affiliation(s)
- Jacques Taillard
- University of Bordeaux, Sommeil, Attention et Neuropsychiatrie, USR 3413, Bordeaux, France.
| | | | | | | | | | | |
Collapse
|
152
|
Sánchez-Ramos C, Bonnin-Arias C, Guerrera MC, Calavia MG, Chamorro E, Montalbano G, López-Velasco S, López-Muñiz A, Germanà A, Vega JA. Light regulates the expression of the BDNF/TrkB system in the adult zebrafish retina. Microsc Res Tech 2012; 76:42-9. [PMID: 23070877 DOI: 10.1002/jemt.22133] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 09/12/2012] [Indexed: 12/21/2022]
Abstract
The retina of the adult zebrafish express brain-derived neurotrophic factor (BDNF) and its signaling receptor TrkB. This functional system is involved in the biology of the vertebrate retina and its expression is regulated by light. This study was designed to investigate the effects of cyclic (12 h light/12 h darkness) or continuous (24 h) exposure during 10 days to white light, white-blue light, and blue light, as well as of darkness, on the expression of BDNF and TrkB in the retina. BDNF and TrkB were assessed in the retina of adult zebrafish using quantitative real-time polymerase chain reaction and immunohistochemistry. Exposure to white, white-blue, and blue light causes a decrease of BDNF mRNA and of BDNF immunostaining, independently of the pattern of light exposition. Conversely, in the same experimental conditions, the expression of TrkB mRNA was upregulated and TrkB immunostaining increased. Exposition to darkness diminished BDNF and TrkB mRNAs, and abolished the immunostaining for BDNF but not modified that for TrkB. These results demonstrate the regulation of BDNF and TrkB by light in the retina of adult zebrafish and might contribute to explain some aspects of the complex pathophysiology of light-induced retinopathies.
Collapse
Affiliation(s)
- C Sánchez-Ramos
- Departamento de Óptica II (Optometría y Visión), Universidad Complutense de Madrid, Madrid, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
153
|
McCusker N, Bailey C, Robinson S, Patel N, Sandy JR, Ireland AJ. Dental light curing and its effects on color perception. Am J Orthod Dentofacial Orthop 2012; 142:355-63. [DOI: 10.1016/j.ajodo.2012.04.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Revised: 04/01/2012] [Accepted: 04/01/2012] [Indexed: 10/28/2022]
|
154
|
INHIBITORY ACTIVITY OF RANIBIZUMAB, SORAFENIB, AND PAZOPANIB ON LIGHT-INDUCED OVEREXPRESSION OF PLATELET-DERIVED GROWTH FACTOR AND VASCULAR ENDOTHELIAL GROWTH FACTOR A AND THE VASCULAR ENDOTHELIAL GROWTH FACTOR A RECEPTORS 1 AND 2 AND NEUROPILIN 1 AND 2. Retina 2012; 32:1652-63. [DOI: 10.1097/iae.0b013e318240a558] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
155
|
Kernt M, Hirneiss C, Wolf A, Liegl R, Rueping J, Neubauer A, Alge C, Ulbig M, Gandorfer A, Kampik A, Haritoglou C. Indocyanine green increases light-induced oxidative stress, senescence, and matrix metalloproteinases 1 and 3 in human RPE cells. Acta Ophthalmol 2012; 90:571-9. [PMID: 20670344 DOI: 10.1111/j.1755-3768.2010.01961.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE Indocyanine green (ICG) is a commonly used vital dye for macular surgery. Recent reports implicate that its use might be associated with less favourable results regarding postoperative visual outcome and damage of retinal cells, and atrophic degeneration of the retinal pigment epithelium (RPE) has been described. This study investigates the effects of ICG on light-induced senescence of RPE cells. METHODS Primary human RPE cells were either pre-incubated with ICG in concentrations of 0.005% and 0.05% or not and then exposed to white light. After 10 min of irradiation viability, induction of intracellular reactive oxygen species (ROS) and senescence-associated β-galactosidase activity (SA β-Gal) were determined. Expression and secretion of matrix metalloproteinases (MMPs) 1 and 3 and their mRNA were determined by RT-PCR and ELISA. RESULTS Light exposure decreased RPE cell viability by 46%. Treatment with 0.005% and 0.05% ICG alone decreased RPE cell viability by 7% and 21%. In addition, expression of ROS, SA β-Gal, and MMP-1 and 3 was significantly increased. When 0.005% and 0.05% ICG treatments were combined with light exposure, viability decreased by 69% and 82% compared to the untreated control. Effects on the expression of ROS, SA β-Gal, and MMP-1 and 3 were, depending on the ICG dose, significantly increased when cells were pre-incubated with ICG and then illuminated. CONCLUSION In this study, pretreatment with ICG significantly increased light-induced oxidative stress and senescence. This might indicate a potential, supplementary mechanism that could explain RPE alterations and reduced functional results after ICG-assisted internal limiting membrane peeling.
Collapse
Affiliation(s)
- Marcus Kernt
- Department of Ophthalmology, Ludwig Maximilian University, Munich, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
156
|
αA crystallin may protect against geographic atrophy-meta-analysis of cataract vs. cataract surgery for geographic atrophy and experimental studies. PLoS One 2012; 7:e43173. [PMID: 22916220 PMCID: PMC3423426 DOI: 10.1371/journal.pone.0043173] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 07/20/2012] [Indexed: 11/29/2022] Open
Abstract
Background Cataract and geographic atrophy (GA, also called advanced “dry” age-related macular degeneration) are the two major causes of visual impairment in the developed world. The association between cataract surgery and the development of GA was controversial in previous studies. Methods/Principal Findings We performed a meta-analysis by pooling the current evidence in literature and found that cataract is associated with an increased risk of geographic atrophy with a summary odds ratio (OR) of 3.75 (95% CI: 95% CI: 1.84–7.62). However, cataract surgery is not associated with the risk of geographic atrophy (polled OR = 3.23, 95% CI: 0.63–16.47). Further experiments were performed to analyze how the αA-crystallin, the major component of the lens, influences the development of GA in a mouse model. We found that theαA-crystallin mRNA and protein expression increased after oxidative stress induced by NaIO3 in immunohistochemistry of retinal section and western blot of posterior eyecups. Both functional and histopathological evidence confirmed that GA is more severe in αA-crystallin knockout mice compared to wild-type mice. Conclusions Therefore, αA-crystallin may protect against geographic atrophy. This study provides a better understanding of the relationship between cataract, cataract surgery, and GA.
Collapse
|
157
|
Improving the repeatability of heterochromatic flicker photometry for measurement of macular pigment optical density. Graefes Arch Clin Exp Ophthalmol 2012; 251:871-80. [PMID: 22899455 DOI: 10.1007/s00417-012-2127-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/12/2012] [Accepted: 07/24/2012] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND Heterochromatic flicker photometry (HFP) is a psychophysical technique used to measure macular pigment optical density (MPOD). We used the MPS 9000 (MPS) HFP device. Our aim was to determine if the repeatability of the MPS could be improved to make it more suitable for monitoring MPOD over time. METHODS Intra-session repeatability was assessed in 25 participants (aged 20-50 years). The resulting data was explored in detail, e.g., by examining the effect of removal and adjustment of data with less than optimal quality parameters. A protocol was developed for improved overall reliability, which was then tested in terms of inter-session repeatability in a separate group of 27 participants (aged 19-52 years). RESULTS Removal and adjustment of data reduced the intra-session coefficient of repeatability (CR) by 0.04, on average, and the mean individual standard deviation by 0.004. Raw data observation offered further insight into ways of improving repeatability. The proposed protocol resulted in an inter-session CR of 0.08. CONCLUSIONS Removal and adjustment of less than optimal data improved repeatability, and is therefore recommended. To further improve repeatability, in brief we propose that each patient perform each part of the test twice, and a third time where necessary (described in detail by the protocol). Doing so will make the MPS more useful in research and clinical settings.
Collapse
|
158
|
MicroRNA-30b-mediated regulation of catalase expression in human ARPE-19 cells. PLoS One 2012; 7:e42542. [PMID: 22880027 PMCID: PMC3412823 DOI: 10.1371/journal.pone.0042542] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 07/09/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Oxidative injury to retinal pigment epithelium (RPE) and retinal photoreceptors has been linked to a number of retinal diseases, including age-related macular degeneration (AMD). Reactive oxygen species (ROS)-mediated gene expression has been extensively studied at transcriptional levels. Also, the post-transcriptional control of gene expression at the level of translational regulation has been recently reported. However, the microRNA (miRNA/miR)-mediated post-transcriptional regulation in human RPE cells has not been thoroughly looked at. Increasing evidence points to a potential role of miRNAs in diverse physiological processes. METHODOLOGY/PRINCIPAL FINDINGS We demonstrated for the first time in a human retinal pigment epithelial cell line (ARPE-19) that the post-transcriptional control of gene expression via miRNA modulation regulates human catalase, an important and potent component of cell's antioxidant defensive network, which detoxifies hydrogen peroxide (H(2)O(2)) radicals. Exposure to several stress-inducing agents including H(2)O(2) has been reported to alter miRNA expression profile. Here, we demonstrated that a sublethal dose of H(2)O(2) (200 µM) up-regulated the expression of miR-30b, a member of the miR-30 family, which inhibited the expression of endogenous catalase both at the transcript and protein levels. However, antisense (antagomirs) of miR-30b was not only found to suppress the miR-30b mimics-mediated inhibitions, but also to dramatically increase the expression of catalase even under an oxidant environment. CONCLUSIONS/SIGNIFICANCE We propose that a microRNA antisense approach could enhance cytoprotective mechanisms against oxidative stress by increasing the antioxidant defense system.
Collapse
|
159
|
Hogg RE, Ong EL, Chamberlain M, Dirani M, Baird PN, Guymer RH, Fitzke F. Heritability of the spatial distribution and peak density of macular pigment: a classical twin study. Eye (Lond) 2012; 26:1217-25. [PMID: 22744384 DOI: 10.1038/eye.2012.98] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To elucidate the heritability of peak density and spatial width of macular pigment (MP) using a Classical Twin Study. METHODS Fundus autofluorescence images were obtained at 488 nm from 86 subjects or 43 twin pairs (21 monozygotic (MZ) and 22 dizygotic (DZ)) (27 male, 59 female) aged from 55 to 76 years (mean 62.2 ± 5.3 years). The relative topographic distribution of MP was measured using a grey scale of intensity (0-255 units) in a 7° eccentricity around the fovea. Relative peak MP density (rPMPD) and relative spatial distribution of MP (rSDMP) were used as the main outcome measure in the statistical analysis. RESULTS A significantly higher correlation was found within MZ pairs as compared with that within DZ pairs for rPMPD, (r=0.99, 95% confidence interval (95% CI) 0.93 to 1.00) and 0.22, 95% CI -0.34 to 0.71), respectively, suggesting strong heritability of this trait. When rSDMP was compared, there was no significant difference between the correlations within MZ pairs (r=0.48, 95% CI -0.02 to 0.83) and DZ pairs (r=0.63, 95% CI 0.32 to 0.83), thus rSDMP is unlikely to have a considerable heritable component. In addition, there was no difference between any MP parameter when normal maculae were compared with early age-related macular degeneration (AMD) (rPMPD 0.36 vs 0.34, t=1.18 P=0.243, rSDMP 1.75 vs 1.75, t=0.028 P=0.977). CONCLUSIONS rPMPD is a strongly heritable trait whereas rSDMP has minimal genetic influence and a greater influence by environmental factors. The presence of macular changes associated with early AMD did not appear to influence any of these pigment parameters.
Collapse
Affiliation(s)
- R E Hogg
- Centre for Vision and Vascular Science, Queen's University, Belfast, UK.
| | | | | | | | | | | | | |
Collapse
|
160
|
Kinnunen PKJ, Kaarniranta K, Mahalka AK. Protein-oxidized phospholipid interactions in cellular signaling for cell death: from biophysics to clinical correlations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2446-55. [PMID: 22542574 DOI: 10.1016/j.bbamem.2012.04.008] [Citation(s) in RCA: 233] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 03/02/2012] [Accepted: 04/10/2012] [Indexed: 11/26/2022]
Abstract
Oxidative stress is associated with several major ailments. However, it is only recently that the developments in our molecular level understanding of the consequences of oxidative stress in modifying the chemical structures of biomolecules, lipids in particular, are beginning to open new emerging insights into the significance of oxidative stress in providing mechanistic insights into the etiologies of these diseases. In this brief review we will first discuss the role of lipid oxidation in controlling the membrane binding of cytochrome c, a key protein in the control of apoptosis. We then present an overview of the impact of oxidized phospholipids on the biophysical properties of lipid bilayers and continue to discuss, how these altered properties can account for the observed enhancement of formation of intermediate state oligomers by cytotoxic amyloid forming peptides associated with pathological conditions as well as host defense peptides of innate immunity. In the third part, we will discuss how the targeting of oxidized phospholipids by i) pathology associated peptides and ii) host defense peptides can readily explain the observed clinical correlations associating Alzheimer's and Parkinson's diseases with increased risk for type 2 diabetes and age-related macular degeneration, and the apparent protective effect of Alzheimer's and Parkinson's diseases from some cancers, as well as the inverse, apparent protection by cancer from Alzheimer's and Parkinson's diseases. This article is part of a Special Issue entitled: Oxidized phospholipids-Their properties and interactions with proteins.
Collapse
Affiliation(s)
- Paavo K J Kinnunen
- Department of Biomedical Engineering and Computational Science, Aalto University, Espoo, Finland.
| | | | | |
Collapse
|
161
|
Sabour-Pickett S, Nolan JM, Loughman J, Beatty S. A review of the evidence germane to the putative protective role of the macular carotenoids for age-related macular degeneration. Mol Nutr Food Res 2012; 56:270-86. [PMID: 22121091 DOI: 10.1002/mnfr.201100219] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 08/09/2011] [Accepted: 08/18/2011] [Indexed: 11/05/2022]
Affiliation(s)
- Sarah Sabour-Pickett
- Department of Optometry; College of Sciences and Health; Dublin Institute of Technology; Dublin Ireland
- Macular Pigment Research Group; Department of Chemical and Life Sciences; Waterford Institute of Technology; Waterford Ireland
| | - John M. Nolan
- Macular Pigment Research Group; Department of Chemical and Life Sciences; Waterford Institute of Technology; Waterford Ireland
- Institute of Vision Research; Whitfield Clinic; Waterford Ireland
| | - James Loughman
- Department of Optometry; College of Sciences and Health; Dublin Institute of Technology; Dublin Ireland
- African Vision Research Institute; Faculty of Health Sciences; University of KwaZulu Natal; Durban South Africa
| | - Stephen Beatty
- Macular Pigment Research Group; Department of Chemical and Life Sciences; Waterford Institute of Technology; Waterford Ireland
- Institute of Vision Research; Whitfield Clinic; Waterford Ireland
| |
Collapse
|
162
|
Turnbull DJ, Parisi AV. Potential dosemeter for quantifying biologically effective blue light exposures. RADIATION PROTECTION DOSIMETRY 2012; 149:245-250. [PMID: 21712257 DOI: 10.1093/rpd/ncr251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper reports on the development of a blue light (VIS(BL)) dosemeter. The VIS(BL) dosemeter is based on the combination of polysulfone and phenothiazine as a potential VIS(BL) dosemeter for population studies of exposures related to the blue light hazard. This research found that this combination of photosensitive chromophores reacts to both ultraviolet and visible wavelengths of the solar spectrum. Further to this, the majority of the ultraviolet wavelengths <380 nm can be filtered out with the use of a low-pass filter. It was found that a large change in optical absorbance at 437 nm occurred when the dosemeter was employed to quantify the solar blue light hazard exposures. Preliminary results indicate that this dosemeter saturates relatively slowly and is able to measure exposures equivalent to >1200 kJ m(-2) of blue light hazard weighted solar radiation.
Collapse
Affiliation(s)
- David J Turnbull
- Centre for Rural and Remote Area Health, University of Southern Queensland, Toowoomba, Queensland 4350, Australia.
| | | |
Collapse
|
163
|
Lee RMH, Cuthbertson FM, Soderberg P, Liu CS. A possible strategy for implanting blue-blocking intraocular lenses. Acta Ophthalmol 2012; 90:e151. [PMID: 21649877 DOI: 10.1111/j.1755-3768.2011.02166.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
164
|
Abstract
OBJECTIVES Although the risks of excess solar ultraviolet (UV) exposure of the skin are well recognized, the need for eye protection is frequently overlooked, or when sunglasses are also recommended, specific guidance is wrong or is not explained. Guidance from the World Health Organization at its InterSun webpage advises people to wear "wrap-around" sunglasses under many conditions. The objective of this study was to examine the need for UV filtration in prescription lenses, contact lenses, and sunglasses. METHODS The geometry of UV exposure of both eyes, solar position, ground reflection, pupil size, and lid opening were studied. Because an accurate determination of cumulative ocular exposure is difficult, the cornea itself can serve as a biologic dosimeter, because photokeratitis is not experienced on a daily basis but does under certain ground-surface and sunlight conditions. From a knowledge of the UV-threshold dose required to produce photokeratitis, we have an upper level of routine ocular exposure to ambient UV. RESULTS From ambient UV measurements and observed photokeratitis, the upper limits of UV exposure of the crystalline lens or an intraocular lens implant are estimated. The risk of excess UV exposure of the germinative cells of the lens is greatest from the side. Sunglasses can actually increase UV exposure of the germinative region of the crystalline lens and the corneal limbus by disabling the eyes' natural protective mechanisms of lid closure and pupil constriction! The level of UV-A risk is difficult to define. CONCLUSIONS Proper UV-absorbing contact lenses offer the best mode for filtering needless exposure of UV radiation of the lens and limbus.
Collapse
|
165
|
|
166
|
Holton H, Christiansen AB, Albeck MJ, Johnsen CR. The impact of light source on discrimination ability in subjects with age-related macular degeneration. Acta Ophthalmol 2011; 89:779-84. [PMID: 20015100 DOI: 10.1111/j.1755-3768.2009.01809.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To examine the influence of light source on letter contrast sensitivity in subjects with age-related macular degeneration (AMD). METHODS Halogen incandescent bulbs and low-energy fluorescent tubes were tested with 70 subjects with AMD. The subjects' contrast sensitivity was determined in a randomized single-blind crossover study for each light source using photopically illuminated Pelli Robson contrast sensitivity charts. The test subjects' subjective light source preference was also determined. RESULTS The mean contrast sensitivity for the incandescent light source was 1.28 ± 0.29 (mean ± SD), and for the fluorescent light source 1.17 ± 0.29, p < 0.001. The illuminance was 338 lux (± 9) for the incandescent light, and 339 lux (± 11) for the fluorescent light. Forty-nine subjects preferred the incandescent light source, while none preferred the fluorescent light source for maximum detail and clarity. Nineteen had no preference. This finding is statistically significant. Fifteen of the 19 subjects without a preference had no difference in contrast sensitivity, which supports their lack of preference. There was no significant difference with regard to sex or order of exposure to light source. Subjects with AMD had significantly reduced contrast sensitivity compared with expected normal values. We found no relationship between visual acuity and contrast sensitivity. CONCLUSION We are only able to recommend photopic full spectral radiance incandescent light sources to visually impaired subjects for their domestic surroundings. Furthermore, we recommend the use of full spectral radiance light sources for the illumination of Pelli-Robson contrast sensitivity charts. Given equal illuminance, as in our study, the findings show that contrast sensitivity was better by illumination with incandescent light with full spectral radiance compared with fluorescent light with interrupted spectral radiance.
Collapse
Affiliation(s)
- Henrik Holton
- The Municipal Resource Centre for Blind and Visually Impaired (Synscentralen), Vordingborg, Denmark.
| | | | | | | |
Collapse
|
167
|
Blueberry anthocyanins: protection against ageing and light-induced damage in retinal pigment epithelial cells. Br J Nutr 2011; 108:16-27. [PMID: 22018225 DOI: 10.1017/s000711451100523x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Retinal pigment epithelium (RPE) cells are vital for retinal health. However, they are susceptible to injury with ageing and exposure to excessive light, including UV (100-380 nm) and visible (380-760 nm) radiation. To evaluate the protective effect of blueberry anthocyanins on RPE cells, in vitro cell models of replicative senescent and light-induced damage were established in the present study. After purification and fractionation, blueberry anthocyanin extracts (BAE) were yielded with total anthocyanin contents of 31·0 (SD 0·5) % and were used in this study. Replicative senescence of RPE cells was induced by repeatedly passaging cells from the fourth passage to the tenth. From the fifth passage, cultured RPE cells began to enter a replicative senescence, exhibiting reduced cell proliferation along with an increase in the number of β-galactosidase-positive cells. RPE cells maintained high cell viability (P < 0·01) and a low (P < 0·01) percentage of β-galactosidase-positive cells when treated with 0·1 μg/ml BAE. In contrast, after exposure to 2500 (SD 500) lx light (420-800 nm) for 12 h, RPE cells in the positive control (light exposure, no BAE treatment) exhibited premature senescence, low (P < 0·01) cell viability and increased (P < 0·01) vascular endothelial growth factor (VEGF) release compared with negative control cells, which were not subjected to light irradiation and BAE exposure. Correspondingly, BAE is beneficial to RPE cells by protecting these cells against light-induced damage through the suppression of ageing and apoptosis as well as the down-regulation of the over-expressed VEGF to normal level. These results demonstrate that BAE is efficacious against senescence and light-induced damage of RPE cells.
Collapse
|
168
|
Abstract
PURPOSE We tested for protection of blue light-exposed A2E-containing retinal pigment epithelial (RPE) from damage through the implementation of polycarbonate filters containing varying levels of a pigment that absorbs short wavelength light. METHODS Human adult RPE cells (ARPE-19) that had accumulated synthesized A2E were exposed to either a light line delivered from a tungsten halogen source (430 ± 20 nm; 8 mW/cm) or to the entire area of a 35 mm dish (1 mW/cm). Blue-light absorbing polycarbonate filters (2.5 × 4 cm) containing varying levels of short-wavelength light absorbing pigment (1.0, 1.9, 3.8, 7.5, 15, and 35 ppm) or no dye (PC) were placed in the light path. Cytotoxicity was measured by the 4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric microtiter assay (Roche Diagnostics Corporation, Indianapolis, IN) or by fluorescent staining of non-viable cells. RESULTS When filters containing blue-light absorbing dye were placed in the light path, protection of 430 nm irradiated A2E-laden RPE was observed. The extent of protection was dependent on the concentration of the dye. By MTT assay and fluorescence labeling, statistically significant differences (p < 0.05) between irradiation in the absence of a filter and irradiation in the presence of a filter were observed. CONCLUSIONS The series of filters tested in this work provided protection against blue light damage in a culture model.
Collapse
|
169
|
Qian J, Keyes KT, Long B, Chen G, Ye Y. Impact of HMG-CoA reductase inhibition on oxidant-induced injury in human retinal pigment epithelium cells. J Cell Biochem 2011; 112:2480-9. [DOI: 10.1002/jcb.23173] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
170
|
Kernt M, Walch A, Neubauer AS, Hirneiss C, Haritoglou C, Ulbig MW, Kampik A. Filtering blue light reduces light-induced oxidative stress, senescence and accumulation of extracellular matrix proteins in human retinal pigment epithelium cells. Clin Exp Ophthalmol 2011; 40:e87-97. [PMID: 21668780 DOI: 10.1111/j.1442-9071.2011.02620.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Cumulative light exposure is significantly associated with ageing and the progression of age-related macular degeneration. To prevent the retina from blue-light damage in pseudophakia, blue light-absorbing intraocular lenses have been developed. This study compares the possible protective effects of a blue light-absorbing intraocular lens to an untinted ultraviolet-absorbing intraocular lens with regard to light-induced oxidative stress and senescence of human retinal pigment epithelium. METHODS As primary human retinal pigment epithelium cells were exposed to white light, either an ultraviolet- and blue light-absorbing intraocular lens or ultraviolet-absorbing intraocular lens was placed in the light beam. After 60 min of irradiation, cells were investigated by electron microscopy for viability, induction of intracellular reactive oxygen species, and senescence-associated β-galactosidase activity. Expression and secretion of matrix metalloproteinases 1 and 3 and their mRNA were determined by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay. RESULTS Light exposure induced structural damage, decreased retinal pigment epithelium cell viability, and increased reactive oxygen species, senescence-associated β-galactosidase activity and matrix metalloproteinases 1 and 3 expression and secretion. Although both types of intraocular lens significantly reduced these effects, the protective effects of the ultraviolet- and blue light-absorbing intraocular lens were significantly stronger than those of the ultraviolet-absorbing intraocular lens. CONCLUSIONS The ultraviolet- and blue light-absorbing intraocular lens demonstrated significantly better protection against light-induced oxidative stress, senescence and structural damage than the ultraviolet-absorbing intraocular lens. These in vitro findings support the hypothesis that the ultraviolet- and blue light-absorbing intraocular lens may prevent retinal damage in clinical use.
Collapse
Affiliation(s)
- Marcus Kernt
- Department of Ophthalmology, Ludwig Maximilians University, Munich, Germany.
| | | | | | | | | | | | | |
Collapse
|
171
|
Gong Y, Qiu Y, Song Z, Gu Q, Wu X, Sun X. Effects of Single Intravitreal rhEPO Injection on Light-Induced Retinal Injury in Rats. Curr Eye Res 2011; 36:739-46. [DOI: 10.3109/02713683.2011.582661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
172
|
Knels L, Valtink M, Roehlecke C, Lupp A, de la Vega J, Mehner M, Funk RHW. Blue light stress in retinal neuronal (R28) cells is dependent on wavelength range and irradiance. Eur J Neurosci 2011; 34:548-58. [PMID: 21781192 DOI: 10.1111/j.1460-9568.2011.07790.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aim of our study was to elucidate the role of wavelength and irradiance in blue light retinal damage. We investigated the impact of blue light emitted from light-emitting diode (LED) modules with peaks at either 411nm (half bandwidth 17nm) or 470nm (half bandwidth 25nm) at defined irradiances of 0.6, 1.5 and 4.5W/m(2) for 411nm and 4.5W/m(2) for 470nm on retinal neuronal (R28) cells in vitro. We observed a reduction in metabolic activity and transmembrane potential of mitochondria when cells were irradiated at 411nm at higher irradiances. Furthermore, production of mitochondrial superoxide radicals increased significantly when cells were irradiated with 411nm light at 4.5W/m(2) . In addition, such irradiation caused an activation of the antioxidative glutathion system. Using vital staining, flow cytometry and western blotting, we were able to show that apoptosis only took place when cells were exposed to 411nm blue light at higher irradiances; necrosis was not observed. Enhanced caspase-3 cleavage product levels confirmed that this effect was dependent on light irradiance. Significant alterations of the above-mentioned parameters were not observed when cells were irradiated with 471nm light despite a high irradiance of 4.5W/m(2) , indicating that the cytotoxic effect of blue light is highly dependent on wavelength. The observed phenomena in R28 cells at 411nm (4.5W/m(2) ) point to an apoptosis pathway elicited by direct mitochondrial damage and increased oxidative stress. Thus, light of 411nm should act via impairment of mitochondrial function by compromising the metabolic situation of these retinal neuronal cells.
Collapse
Affiliation(s)
- Lilla Knels
- Department of Anatomy, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany.
| | | | | | | | | | | | | |
Collapse
|
173
|
Recent studies provide an updated clinical perspective on blue light-filtering IOLs. Graefes Arch Clin Exp Ophthalmol 2011; 249:957-68. [PMID: 21584764 PMCID: PMC3124647 DOI: 10.1007/s00417-011-1697-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 11/10/2022] Open
Abstract
Background Recent reviews of blue light-filtering intraocular lenses (IOLs) have stated their potential risks for scotopic vision and circadian photoentrainment. Some authors have challenged the rationale for retinal photoprotection that these IOLs might provide. Our objective is to address these issues by providing an updated clinical perspective based on the results of the most recent studies. Methods This article evaluates the currently available published papers assessing the potential risks and benefits of blue light-filtering IOLs. It summarizes the results of seven clinical and two computational studies on photoreception, and several studies related to retinal photoprotection, all of which were not available in the previous reviews. These results provide a clinical risk/benefit analysis for an updated review for these IOLs. Results Most clinical studies comparing IOLs with and without the blue light-filtering feature have found no difference in clinical performance for; visual acuity, contrast sensitivity, color vision, or glare. For blue light-filtering IOLs, three comparative clinical studies have shown improved contrast sensitivity and glare reduction; but one study, while it showed satisfactory overall color perception, demonstrated some compromise in mesopic comparative blue color discrimination. Comparative results of two recent clinical studies have also shown improved performance for simulated driving under glare conditions and reduced glare disability, better heterochromatic contrast threshold, and faster recovery from photostress for blue light-filtering IOLs. Two computational and five clinical studies found no difference in performance between IOLs with or without blue light-filtration for scotopic vision performance and photo entrainment of the circadian rhythm. The rationale for protection of the pseudophakic retina against phototoxicity is discussed with supporting results of the most recent computational, in-vitro, animal, clinical, and epidemiological investigations. Conclusions This analysis provides an updated clinical perspective which suggests the selection of blue light-filtering IOLs for patients of any age, but especially for pediatric and presbyopic lens exchange patients with a longer pseudophakic life. Without clinically substantiated potential risks, these patients should experience the benefit of overall better quality of vision, reduced glare disability at least in some conditions, and better protection against retinal phototoxicity and its associated potential risk for AMD. Electronic supplementary material The online version of this article (doi:10.1007/s00417-011-1697-6) contains supplementary material, which is available to authorized users.
Collapse
|
174
|
Behar-Cohen F, Martinsons C, Viénot F, Zissis G, Barlier-Salsi A, Cesarini JP, Enouf O, Garcia M, Picaud S, Attia D. Light-emitting diodes (LED) for domestic lighting: any risks for the eye? Prog Retin Eye Res 2011; 30:239-57. [PMID: 21600300 DOI: 10.1016/j.preteyeres.2011.04.002] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 04/21/2011] [Accepted: 04/29/2011] [Indexed: 12/11/2022]
Abstract
Light-emitting diodes (LEDs) are taking an increasing place in the market of domestic lighting because they produce light with low energy consumption. In the EU, by 2016, no traditional incandescent light sources will be available and LEDs may become the major domestic light sources. Due to specific spectral and energetic characteristics of white LEDs as compared to other domestic light sources, some concerns have been raised regarding their safety for human health and particularly potential harmful risks for the eye. To conduct a health risk assessment on systems using LEDs, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES), a public body reporting to the French Ministers for ecology, for health and for employment, has organized a task group. This group consisted physicists, lighting and metrology specialists, retinal biologist and ophthalmologist who have worked together for a year. Part of this work has comprised the evaluation of group risks of different white LEDs commercialized on the French market, according to the standards and found that some of these lights belonged to the group risk 1 or 2. This paper gives a comprehensive analysis of the potential risks of white LEDs, taking into account pre-clinical knowledge as well as epidemiologic studies and reports the French Agency's recommendations to avoid potential retinal hazards.
Collapse
Affiliation(s)
- F Behar-Cohen
- Inserm UMRS 872, Physiopathology of Ocular Diseases: Therapeutic Innovations, Centre de Recherche des Cordeliers, Paris, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
175
|
Walker DP, Vollmer-Snarr HR, Eberting CLD. Ocular hazards of blue-light therapy in dermatology. J Am Acad Dermatol 2011; 66:130-5. [PMID: 21536341 DOI: 10.1016/j.jaad.2010.11.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 09/28/2010] [Accepted: 11/04/2010] [Indexed: 12/11/2022]
Abstract
Blue-light phototherapy has become important in the treatment of many dermatologic conditions and as a result continue to be developed. Although blue-light therapy is successful, research shows that excessive ocular blue-light exposure may contribute to age-related macular degeneration and other vision problems. As blue-light therapy becomes increasingly more popular for clinical and at-home use, patients and operators of blue-light devices should be aware of its associated ocular hazards. Protective eyewear should be carefully selected and implemented with each therapy session to guard against the development of retinal disease.
Collapse
Affiliation(s)
- Daniel P Walker
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | | |
Collapse
|
176
|
Nolan JM, Loughman J, Akkali MC, Stack J, Scanlon G, Davison P, Beatty S. The impact of macular pigment augmentation on visual performance in normal subjects: COMPASS. Vision Res 2011; 51:459-69. [DOI: 10.1016/j.visres.2010.12.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 12/08/2010] [Accepted: 12/28/2010] [Indexed: 10/18/2022]
|
177
|
Macular pigment optical density measurements: evaluation of a device using heterochromatic flicker photometry. Eye (Lond) 2010; 25:105-12. [PMID: 21057522 DOI: 10.1038/eye.2010.164] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Accurate assessment of the amount of macular pigment (MPOD) is necessary to investigate the role of carotenoids and their assumed protective functions. High repeatability and reliability are important to monitor patients in studies investigating the influence of diet and supplements on MPOD. We evaluated the Macuscope (Macuvision Europe Ltd., Lapworth, Solihull, UK), a recently introduced device for measuring MPOD using the technique of heterochromatic flicker photometry (HFP). We determined agreement with another HFP device (QuantifEye; MPS 9000 series: Tinsley Precision Instruments Ltd., Croydon, Essex, UK) and a fundus reflectance method. METHODS The right eyes of 23 healthy subjects (mean age 33.9 ± 15.1 years) were measured. We determined agreement with QuantifEye and correlation with a fundus reflectance method. Repeatability of QuantifEye was assessed in 20 other healthy subjects (mean age 32.1 ± 7.3 years). Repeatability was also compared with measurements by a fundus reflectance method in 10 subjects. RESULTS We found low agreement between test and retest measurements with Macuscope. The average difference and the limits of agreement were -0.041 ± 0.32. We found high agreement between test and retest measurements of QuantifEye (-0.02 ± 0.18) and the fundus reflectance method (-0.04 ± 0.18). MPOD data obtained by Macuscope and QuantifEye showed poor agreement: -0.017 ± 0.44. For Macuscope and the fundus reflectance method, the correlation coefficient was r = 0.05 (P = 0.83). A significant correlation of r = 0.87 (P<0.001) was found between QuantifEye and the fundus reflectance method. CONCLUSIONS Because repeatability of Macuscope measurements was low (ie, wide limits of agreement) and MPOD values correlated poorly with the fundus reflectance method, and agreed poorly with QuantifEye, the tested Macuscope protocol seems less suitable for studying MPOD.
Collapse
|
178
|
Abstract
Ischemia and hypoxia have been implicated in the pathophysiology of age related macular degeneration (AMD). This has mostly been based on studies on choroidal perfusion, which is not the only contributor to retinal hypoxia found in AMD eyes. Other features of AMD may also interfere with retinal oxygen metabolism including confluent drusen, serous or hemorrhagic retinal detachment, retinal edema and vitreoretinal adhesion. Each of these features contributes to retinal hypoxia: the drusen and retinal elevation by increasing the distance between the choriocapillaris and retina; vitreoretinal adhesion by reducing diffusion and convection of oxygen towards and vascular endothelial growth factor (VEGF) away from hypoxic retinal areas. Hypoxia-inducible-factor is known to exist in subretinal neovascularization and hypoxia is the main stimulus for the production of VEGF. Each feature may not by itself create enough hypoxia and VEGF accumulation to stimulate wet AMD, but they may combine to do so. Choroidal ischemia in AMD has been demonstrated by many researchers, using different technologies. Choroidal ischemia obviously decreases oxygen delivery to the outer retina. Confluent drusen, thickening of Bruch's membrane and any detachment of retina or retinal pigment epithelium, increases the distance between the choriocapillaris and the retina and thereby reduces the oxygen flux from the choroid to the outer retina according to Fick's law of diffusion. Retinal elevation and choroidal ischemia may combine forces to reduce choroidal oxygen delivery to the outer retina, produce retinal hypoxia. Hypoxia leads to production of VEGF leading to neovascularization and tissue edema. A vicious cycle may develop, where VEGF production increases effusion, retinal detachment and edema, further increasing hypoxia and VEGF production. Adhesion of the viscous posterior vitreous cortex to the retina maintains a barrier to diffusion and convection currents in the vitreous cavity according to the laws of Fick's, Stokes-Einstein and Hagen-Poiseuille. If the vitreous is detached from the surface of the retina, the low viscosity fluid transports oxygen and nutrients towards an ischemic area of the retina, and cytokines away from the retina, at a faster rate than through attached vitreous gel. Vitreoretinal adhesion can exacerbate retinal hypoxia and accumulation of cytokines, such as VEGF. Vitreoretinal traction can also cause hypoxia by retinal elevation. Conceivably, the basic features of AMD, drusen, choroidal ischemia, and vitreoretinal adhesion are independently determined by genetics and environment and may combine in variable proportions. If the resulting hypoxia and consequent VEGF accumulation crosses a threshold, this will trigger effusion and neovascularization.
Collapse
Affiliation(s)
- Einar Stefánsson
- University of Iceland, National University Hospital, 101 Reykjavík, Iceland.
| | | | | |
Collapse
|
179
|
Jang SY, Ohn YH, Kim SW. Effect of yellow-tinted intraocular lenses on short-wavelength automated perimetry. Am J Ophthalmol 2010; 150:243-247.e1. [PMID: 20525530 DOI: 10.1016/j.ajo.2010.02.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 02/25/2010] [Accepted: 02/25/2010] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate the effect of yellow-tinted intraocular lenses (IOLs) on short-wavelength automated perimetry (SWAP). DESIGN Cross-sectional observation study. METHODS Twenty-two patients who had implantation of yellow-tinted IOLs (AcrySof SN60AT or SN60WF; Alcon Laboratories) in 1 eye and nontinted IOLs (AcrySof SA60AT) in the other eye were included in the study. Standard automated perimetry (SAP) and SWAP were performed. The results for the mean deviation (MD), pattern standard deviation (PSD), and glaucoma hemifield test results were compared intra-individually. RESULTS There was no statistically significant difference between the IOLs on the SAP (MD, PSD; P = .851, P = .388, respectively). However, a significant difference was observed between the IOLs on the SWAP (MD, PSD; P = .033, P = .033, respectively). The glaucoma hemifield test did not show significant differences in the SAP (P = .083). However, the SWAP showed significant differences (P = .003). CONCLUSIONS The yellow-tinted IOLs may affect the results of the SWAP; therefore, caution is needed in interpreting the results of the SWAP in eyes with implanted yellow-tinted IOLs.
Collapse
|
180
|
|
181
|
van der Veen RL, Fuijkschot J, Willemsen MA, Cruysberg JR, Berendschot TT, Theelen T. Patients with Sjögren-Larsson Syndrome Lack Macular Pigment. Ophthalmology 2010; 117:966-71. [DOI: 10.1016/j.ophtha.2009.10.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 10/06/2009] [Accepted: 10/06/2009] [Indexed: 11/26/2022] Open
|
182
|
Kaczara P, Sarna T, Burke JM. Dynamics of H2O2 availability to ARPE-19 cultures in models of oxidative stress. Free Radic Biol Med 2010; 48:1064-70. [PMID: 20100568 PMCID: PMC2839027 DOI: 10.1016/j.freeradbiomed.2010.01.022] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 12/14/2009] [Accepted: 01/15/2010] [Indexed: 11/23/2022]
Abstract
Oxidative injury to cells such as the retinal pigment epithelium (RPE) is often modeled using H(2)O(2)-treated cultures, but H(2)O(2) concentrations are not sustained in culture medium. Here medium levels of H(2)O(2) and cytotoxicity were analyzed in ARPE-19 cultures after H(2)O(2) delivery as a single pulse or with continuous generation using glucose oxidase (GOx). When added as a pulse, H(2)O(2) is rapidly depleted (within 2 h); cytotoxicity at 24 h, determined by the MTT assay for mitochondrial function, is unaffected by medium replacement at 2 h. Continuous generation of H(2)O(2) produces complex outcomes. At low GOx concentrations, H(2)O(2) levels are sustained by conditions under which generation matches depletion, but when GOx concentrations produce cytotoxic levels of H(2)O(2), oxidant depletion accelerates. Acceleration results partly from the release of contents from oxidant-damaged cells as indicated by testing depletion after controlled membrane disruption with detergents. Cytotoxicity analyses show that cells can tolerate short exposure to high H(2)O(2) doses delivered as a pulse but are susceptible to lower chronic doses. The results provide broadly applicable guidance for using GOx to produce sustained H(2)O(2) levels in cultured cells. This approach will be specifically useful for modeling chronic stress relevant to RPE aging and have a wider value for studying cellular effects of sublethal oxidant injury and for evaluating antioxidants that may protect significantly against mild but not lethal stress.
Collapse
Affiliation(s)
- Patrycja Kaczara
- Department of Biophysics, Jagiellonian University, Kraków, Poland
| | - Tadeusz Sarna
- Department of Biophysics, Jagiellonian University, Kraków, Poland
| | - Janice M. Burke
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI
| |
Collapse
|
183
|
The relationship between macular pigment and visual performance. Vision Res 2010; 50:1249-56. [PMID: 20394766 DOI: 10.1016/j.visres.2010.04.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/30/2010] [Accepted: 04/08/2010] [Indexed: 11/23/2022]
Abstract
This study was designed to assess whether macular pigment optical density (MPOD) is associated with visual performance. One hundred and forty-two young healthy subjects were recruited. Macular pigment optical density and visual performance were assessed by psychophysical tests including best corrected visual acuity (BCVA), mesopic and photopic contrast sensitivity, glare sensitivity, photostress recovery time (PRT). Measures of central visual function, including BCVA and contrast sensitivity, were positively associated with MPOD (p<0.05, for all). Photostress recovery and glare sensitivity were unrelated to MPOD (p>0.05). A longitudinal, placebo-controlled and randomized supplementation trial will be required to ascertain whether augmentation of MPOD can influence visual performance.
Collapse
|
184
|
Ma L, Lin XM. Effects of lutein and zeaxanthin on aspects of eye health. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2010; 90:2-12. [PMID: 20355006 DOI: 10.1002/jsfa.3785] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Lutein and zeaxanthin are members of the oxygenated carotenoids found particularly in egg yolks and dark-green leafy vegetables. A great deal of research has focused on their beneficial roles in eye health. The present article summarises the current literature related to the bioactivity of these carotenoids, emphasising their effects and possible mechanisms of action in relation to human eye health. Available evidence demonstrates that lutein and zeaxanthin are widely distributed in a number of body tissues and are uniquely concentrated in the retina and lens, indicating that each has a possible specific function in these two vital ocular tissues. Most of epidemiological studies and clinical trials support the notion that lutein and zeaxanthin have a potential role in the prevention and treatment of certain eye diseases such as age-related macular degeneration, cataract and retinitis pigmentosa. The biological mechanisms for the protective effects of these carotenoids may include powerful blue-light filtering activities and antioxidant properties. Although most studies point towards significant health benefits from lutein and zeaxanthin, further large-scale randomised supplementation trials are needed to define their effects on ocular function in health and disease.
Collapse
Affiliation(s)
- Le Ma
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | | |
Collapse
|
185
|
Wielgus AR, Collier RJ, Martin E, Lih FB, Tomer KB, Chignell CF, Roberts JE. Blue light induced A2E oxidation in rat eyes – experimental animal model of dry AMD. Photochem Photobiol Sci 2010; 9:1505-12. [DOI: 10.1039/c0pp00133c] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
186
|
Wang SQ, Balagula Y, Osterwalder U. Photoprotection: a Review of the Current and Future Technologies. Dermatol Ther 2010; 23:31-47. [PMID: 20136907 DOI: 10.1111/j.1529-8019.2009.01289.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Steven Q Wang
- Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
| | | | | |
Collapse
|
187
|
Bian ZM, Elner SG, Elner VM. Dual involvement of caspase-4 in inflammatory and ER stress-induced apoptotic responses in human retinal pigment epithelial cells. Invest Ophthalmol Vis Sci 2009; 50:6006-14. [PMID: 19643964 PMCID: PMC3208232 DOI: 10.1167/iovs.09-3628] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate the functional involvement of caspase-4 in human retinal pigment epithelial (hRPE) cells. METHODS Expression and activation of caspase-4 in hRPE cells were measured after stimulation with proinflammatory agents IL-1beta (2 ng/mL), TNF-alpha (20 ng/mL), lipopolysaccharide (1000 ng/mL), interferon-gamma (500 U/mL), or monocyte coculture in the absence or presence of immunomodulating agent cyclosporine (3 or 30 ng/mL), dexamethasone (10 microM), or IL-10 (100 U/mL) and endoplasmic reticulum (ER) stress inducer thapsigargin (25 nM) or tunicamycin (3 or 10 microM). The onset of ER stress was determined by expression of GRP78. The involvement of caspase-4 in inflammation and apoptosis was further examined by treating the cells with caspase-4 inhibitor Z-LEVD-fmk, caspase-1 and -4 inhibitor Z-YVAD-fmk, and pan-caspase inhibitor Z-VAD-fmk. RESULTS Caspase-4 mRNA expression and protein activation were induced by all the proinflammatory agents and ER stress inducers tested in this study. Caspase-4 activation was blocked or reduced by dexamethasone and IL-10. Elevated ER stress by proinflammatory agents and ER stress inducers was shown by increased expression of the ER stress marker GRP78. The induced caspase-4 and caspase-3 activities by tunicamycin and the stimulated IL-8 protein expression by IL-1beta were markedly reduced by caspase-4 inhibitor Z-LEVD-fmk. Although caspase-4 inhibitor Z-LEVD-fmk and caspase-1 and -4 inhibitor Z-YVAD-fmk reduced tunicamycin-induced hRPE apoptotic cell death by 59% and 86%, respectively, pan-caspase inhibitor Z-VAD-fmk completely abolished the induced apoptosis. CONCLUSIONS Caspase-4 is dually involved in hRPE proinflammatory and proapoptotic responses. Various proinflammatory stimuli and ER stress induce hRPE caspase-4 mRNA synthesis and protein activation. ER stress-induced hRPE cell death is caspase and, in part, caspase-4 dependent.
Collapse
Affiliation(s)
- Zong-Mei Bian
- Department of Ophthalmology, University of Michigan, Ann Arbor, Michigan 48105, USA
| | | | | |
Collapse
|
188
|
Whitcomb T, Sakurai K, Brown BM, Young JE, Sheflin L, Dlugos C, Craft CM, Kefalov VJ, Khani SC. Effect of g protein-coupled receptor kinase 1 (Grk1) overexpression on rod photoreceptor cell viability. Invest Ophthalmol Vis Sci 2009; 51:1728-37. [PMID: 19834036 DOI: 10.1167/iovs.09-4499] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PURPOSE Photoreceptor rhodopsin kinase (Rk, G protein-dependent receptor kinase 1 [Grk1]) phosphorylates light-activated opsins and channels them into an inactive complex with visual arrestins. Grk1 deficiency leads to human retinopathy and heightened susceptibility to light-induced photoreceptor cell death in the mouse. The goal of this study was to determine whether excess Grk1 activity is protective against photoreceptor cell death. METHODS Grk1-overexpressing transgenic mice (Grk1(+)) were generated by using a bacterial artificial chromosome (BAC) construct containing mouse Grk1, along with its flanking sequences. Quantitative reverse transcription-PCR, immunoblot analysis, immunostaining, and activity assays were combined with electrophysiology and morphometric analysis, to evaluate Grk1 overexpression and its effect on physiologic and morphologic retinal integrity. Morphometry and nucleosome release assays measured differences in resistance to photoreceptor cell loss between control and transgenic mice exposed to intense light. RESULTS Compared with control animals, the Grk1(+) transgenic line had approximately a threefold increase in Grk1 transcript and immunoreactive protein. Phosphorylated opsin immunochemical staining and in vitro phosphorylation assays confirmed proportionately higher Grk1 enzyme activity. Grk1(+) mice retained normal rod function, normal retinal appearance, and lacked evidence of spontaneous apoptosis when reared in cyclic light. In intense light, Grk1(+) mice showed photoreceptor damage, and their susceptibility was more pronounced than that of control mice with prolonged exposure times. CONCLUSIONS Enhancing visual pigment deactivation does not appear to protect against apoptosis; however, excess flow of opsin into the deactivation pathway may actually increase susceptibility to stress-induced cell death similar to some forms of retinal degeneration.
Collapse
Affiliation(s)
- Tiffany Whitcomb
- Ross Eye Institute, State University of New York at Buffalo, New York, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
189
|
van der Veen RLP, Berendschot TTJM, Hendrikse F, Carden D, Makridaki M, Murray IJ. A new desktop instrument for measuring macular pigment optical density based on a novel technique for setting flicker thresholds. Ophthalmic Physiol Opt 2009; 29:127-37. [PMID: 19236582 DOI: 10.1111/j.1475-1313.2008.00618.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A rapid portable technique for estimating macular pigment optical density (MPOD) in large populations is described. The new instrument utilises a novel method for setting flicker thresholds which is undemanding for naïve and elderly observers and easily operated by a non-technical person. The method has good repeatability (r = 0.97) and the data are comparable with an optical method based on retinal reflectometry (r = 0.78). MPOD spatial profiles are presented for seven normal observers and these are well described (r = 0.99) by a decaying exponential function consistent with previous reports. MPOD values are presented from 5581 (2435 females and 3146 males) individuals measured in 48 optometric practices. The mean MPOD of this population was 0.33 (S.D. +/- 0.187) which is similar to previous large scale studies of MP.
Collapse
|
190
|
Sparrow JR, Wu Y, Kim CY, Zhou J. Phospholipid meets all-trans-retinal: the making of RPE bisretinoids. J Lipid Res 2009; 51:247-61. [PMID: 19666736 DOI: 10.1194/jlr.r000687] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The lipid phase of the photoreceptor outer segment membrane is essential to the photon capturing and signaling functions of rhodopsin. Rearrangement of phospholipids in the bilayer accompanies the formation of the active intermediates of rhodopsin following photon absorption. Furthermore, evidence for the formation of a condensation product between the photolyzed chromophore all-trans-retinal and phosphatidylethanolamine indicates that phospholipid may also participate in the movement of the retinoid in the membrane. The downside of these interactions is the formation of bisretinoid-phosphatidylethanolamine compounds that accumulate in retinal pigment epithelial cells with age and that are particularly abundant in some retinal disorders. The propensity of these compounds to negatively impact on the cells has been linked to the pathogenesis of some retinal disorders including juvenile onset recessive Stargardt disease and age-related macular degeneration.
Collapse
Affiliation(s)
- Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA.
| | | | | | | |
Collapse
|
191
|
Cuthbertson FM, Peirson SN, Wulff K, Foster RG, Downes SM. Blue light–filtering intraocular lenses: Review of potential benefits and side effects. J Cataract Refract Surg 2009; 35:1281-97. [DOI: 10.1016/j.jcrs.2009.04.017] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 02/20/2009] [Accepted: 04/07/2009] [Indexed: 11/16/2022]
|
192
|
Kernt M, Hirneiss C, Neubauer A, Lackerbauer C, Eibl K, Wolf A, Ulbig MW, Kampik A. Protektive Wirkung Blaulicht absorbierender IOLs auf das menschliche retinale Pigmentepithel. Ophthalmologe 2009; 107:150-7. [DOI: 10.1007/s00347-009-1945-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
193
|
Kernt M, Neubauer AS, Liegl R, Eibl KH, Alge CS, Lackerbauer CA, Ulbig MW, Kampik A. Cytoprotective effects of a blue light-filtering intraocular lens on human retinal pigment epithelium by reducing phototoxic effects on vascular endothelial growth factor-alpha, Bax, and Bcl-2 expression. J Cataract Refract Surg 2009; 35:354-62. [PMID: 19185255 DOI: 10.1016/j.jcrs.2008.10.052] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2008] [Revised: 10/17/2008] [Accepted: 10/21/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE To compare the possible protective effects of the ultraviolet (UV)-filtering and blue light-filtering SN60AT intraocular lens (IOL) and the untinted UV-filtering SA60AT IOL with regard to light-induced stress on human retinal pigment epithelium (RPE). SETTING Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany. METHODS Primary human RPE cells were exposed to white light, and a tinted or untinted IOL was placed in the light beam. After 15 to 60 minutes of irradiation, cell viability was determined by a colorimetric test (tetrazolium dye-reduction assay) and a microscopic live/dead assay. The expression of vascular endothelial growth factor-alpha (VEGF-alpha), Bax, and Bcl-2 and their mRNA was determined by reverse-transcription polymerase chain reaction (RT-PCR) and Western blotting. RESULTS Without an IOL, white-light exposure decreased cell viability compared with the decrease with the nonirradiated control in a time-dependent manner. Light-induced cell death was significantly reduced by both the tinted IOL and untinted IOL. The combined UV and blue-light filtering attenuated light-induced cell damage significantly more than UV filtering alone. Results of RT-PCR and Western blotting showed a significant time-dependent decrease in Bcl-2 and increase in Bax and VEGF-alpha that were significantly less with the tinted IOL than with the untinted IOL. CONCLUSIONS Both IOLs reduced light-induced RPE damage. The UV- and blue light-filtering IOL reduced damage more than the conventional IOL. This supports the hypothesis that blue light-filtering IOLs may prevent retinal damage in clinical use.
Collapse
Affiliation(s)
- Marcus Kernt
- Department of Ophthalmology, Ludwig Maximilian University, Munich, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
194
|
Kang KH, Lemke G, Kim JW. The PI3K-PTEN tug-of-war, oxidative stress and retinal degeneration. Trends Mol Med 2009; 15:191-8. [PMID: 19380252 DOI: 10.1016/j.molmed.2009.03.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 03/06/2009] [Accepted: 03/06/2009] [Indexed: 01/01/2023]
Abstract
The retinal pigment epithelium (RPE) is indispensable for photoreceptor function, not only because it provides functional photopigments to photoreceptors, but also because it eliminates oxidatively damaged materials from photoreceptors. Maintaining homeostatic antioxidative programs that support a healthy RPE is therefore important for the normal functioning of the eye. These homeostatic mechanisms, however, often fail in aged RPE cells that have been exposed repeatedly to excessive oxidative stress. When RPE cells succumb to oxidative stress, their death contributes to the development of retinal degenerative diseases such as age-related macular degeneration. Recent studies have highlighted the importance of reciprocal phosphoinositide signaling events orchestrated by phosphoinositide 3-kinase (PI3K) and phosphatase and tensin homolog (PTEN) in the homeostatic programs that protect RPE cells against oxidative stress. Here, we discuss the role of PI3K signaling pathways in RPE cells and suggest that they might be crucial targets of oxidative molecules that initiate early pathological events in retinal degenerative diseases.
Collapse
Affiliation(s)
- Kyung Hwa Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, South Korea
| | | | | |
Collapse
|
195
|
Effects of 400nm, 420nm, and 435.8nm radiations on cultured human retinal pigment epithelial cells. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2009; 95:64-70. [DOI: 10.1016/j.jphotobiol.2009.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 11/28/2008] [Accepted: 01/06/2009] [Indexed: 11/24/2022]
|
196
|
Abstract
The possibility that the macular carotenoids, lutein (L), and zeaxanthin (Z), could retard age-related changes in the eye and prevent the eye diseases that result from such changes (namely, cataract and macular degeneration) has been carefully studied. A role for the carotenoids very early in life, however, has received far less attention. Nevertheless, an influence on visual development is likely. Retinal L and Z, for instance, would influence the development of the visual system if they 1) altered input during a critical/sensitive period of visual development and/or 2) influenced maturation and/or 3) protected the retina during a period when it was particularly vulnerable. The available evidence indicates that the pigments may play a role in all three of these areas.
Collapse
Affiliation(s)
- Billy R Hammond
- Vision Sciences Laboratory, University of Georgia, Athens, Georgia 30602, USA
| |
Collapse
|
197
|
Miyazawa M, Ishii T, Yasuda K, Noda S, Onouchi H, Hartman PS, Ishii N. The role of mitochondrial superoxide anion (O2(-)) on physiological aging in C57BL/6J mice. JOURNAL OF RADIATION RESEARCH 2009; 50:73-83. [PMID: 19218782 DOI: 10.1269/jrr.08097] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Much attention has been focused on the mitochondrial superoxide anion (O2(-)), which is also a critical free radial produced by ionizing radiation. The specific role of the mitochondrial O2(-) on physiological aging in mammals is still unclear despite wide-spread evidence that oxidative stress is involved in aging and age-related diseases. The major endogenous source of O2(-) is generated as a byproduct of energy metabolism from mitochondria. In order to better understand how O2(-)relates to metazoan aging, we have comprehensively examined age-related changes in the levels of oxidative damage, mitochondrial O2(-) production, mitochondrial antioxidant enzyme activity and apoptosis induction in key organs of an inbred mouse strain (C57BL/6J). Oxidative damage accumulated and excess apoptosis occurred in the brain, oculus and kidney with aging, but comparatively little occurred in the heart and muscle. These rates are correlated with O2(-) levels. Mitochondrial O2(-) production levels increased with aging in the brain, oculus and kidney, and did not significantly increased in the heart and muscle. In contrast to O2(-) production, mitochondrial SOD activities increased in heart and muscle, and remained unchanged in the brain, oculus and kidney with aging. These results suggest that O2(-) production has high organ specificity, and oxidative damage by O2(-) from mitochondria mediated apoptosis can lead to organ atrophy and physiological dysfunction. In addition, O2(-) from mitochondria plays a core role in physiological aging.
Collapse
Affiliation(s)
- Masaki Miyazawa
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | | | | | | | | | | | | |
Collapse
|
198
|
Burke JM, Zareba M. Sublethal photic stress and the motility of RPE phagosomes and melanosomes. Invest Ophthalmol Vis Sci 2008; 50:1940-7. [PMID: 19074812 DOI: 10.1167/iovs.08-2671] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine whether sublethal oxidative stress to the retinal pigment epithelium by visible light treatment affects the translocation of organelles, notably phagosomes and melanosomes. METHODS Isolated porcine melanosomes were phagocytized by ARPE-19 cells, then cultures were treated with blue light to generate reactive oxygen intermediates (ROIs) by endogenous retinal pigment epithelial (RPE) chromophores throughout the cytoplasm. Other melanosomes were preloaded with a photosensitizer before phagocytosis, and cells were light treated to generate ROIs specifically at the granule surface. Phagosome movement was analyzed by live cell imaging. Also analyzed were phagocytized black latex beads, phagocytized melanosomes pretreated to simulate age-related melanin photobleaching, and endogenous RPE melanosomes in primary cultures of porcine retinal pigment epithelium. RESULTS Sublethal blue light treatment slowed the movement of some, but not all, phagocytized melanosomes. All phagosomes slowed when ROIs were generated near the organelles through a photosensitized reaction. Melanosome photobleaching, which makes granules more photoreactive, increased the effects of blue light. Blue light treatment also slowed the motility of phagosomes containing latex beads and endogenous pigment granules. CONCLUSIONS Blue light-induced stress impairs phagosome motility in RPE cells but affects individual organelles differently, suggesting that the effects of mild oxidative injury vary with subcellular location. The mechanisms underlying slowed motility are at least partially local because slowing can be induced by a photosensitized reaction in the subdomain of the organelle and the magnitude of the slowing is greater when the phagosome contents are photoreactive. Photic stress may impair the movement and positioning of RPE organelles, which would have widespread consequences for maintaining a functionally efficient subcellular organization.
Collapse
Affiliation(s)
- Janice M Burke
- Department of Ophthalmology, The Eye Institute, Medical College of Wisconsin, Milwaukee, Wisconsin 53226-4812, USA.
| | | |
Collapse
|
199
|
Carson D, Margrain TH, Patel A. New approach to evaluate retinal protection by intraocular lenses against age-related lipofuscin accumulation-mediated retinal phototoxicity. J Cataract Refract Surg 2008; 34:1785-92. [PMID: 18812134 DOI: 10.1016/j.jcrs.2008.06.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 06/02/2008] [Indexed: 11/27/2022]
Abstract
PURPOSE To present a new approach for evaluating intraocular lenses (IOLs) for retinal protection from age-related lipofuscin accumulation-mediated phototoxicity. SETTING Alcon Laboratories Inc., Fort Worth, Texas, USA, and Cardiff University, Cardiff, United Kingdom. METHODS Age-related lipofuscin accumulation-mediated action spectra for retinal phototoxicity in an aphakic eye were created for this evaluation. Transmission curves for 6 IOLs and for cornea and spectral radiant power distribution for sunlight and 2 lamps were used. Pseudophakic action spectra and retinal phototoxicity for 3 wavelength ranges and 3 ages were computed. The percentage protection of each IOL was computed as the reduction in phototoxicity relative to the aphakic eye. RESULTS Retinal phototoxicity increased 3.66 times from the third to ninth decade of age. The comparative retinal phototoxicity and retinal protection provided by IOLs were dependent on the light source and range of wavelength; however, unlike phototoxicity, retinal protection was independent of age. The 420 to 480 nm range was the most useful for discriminating protection by IOLs. CONCLUSIONS Retinal phototoxicity significantly increased with age; however, the retinal protection by IOLs was independent of age. The interaction between the transmission curve of IOLs and light sources required inclusion of widely used lamps besides sunlight for evaluation of IOLs. For the 420 to 480 nm wavelength range, the 3 light sources clearly discriminated the protection provided by IOLs. The AcrySof Natural IOL (Alcon) provided the highest protection consistently for the tested light sources.
Collapse
|
200
|
Burke JM. Epithelial phenotype and the RPE: is the answer blowing in the Wnt? Prog Retin Eye Res 2008; 27:579-95. [PMID: 18775790 DOI: 10.1016/j.preteyeres.2008.08.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Cells of the human retinal pigment epithelium (RPE) have a regular epithelial cell shape within the tissue in situ, but for reasons that remain elusive the RPE shows an incomplete and variable ability to re-develop an epithelial phenotype after propagation in vitro. In other epithelial cell cultures, formation of an adherens junction (AJ) composed of E-cadherin plays an important early inductive role in epithelial morphogenesis, but E-cadherin is largely absent from the RPE. In this review, the contribution of cadherins, both minor (E-cadherin) and major (N-cadherin), to RPE phenotype development is discussed. Emphasis is placed on the importance for future studies of actin cytoskeletal remodeling during assembly of the AJ, which in epithelial cells results in an actin organization that is characteristically zonular. Other markers of RPE phenotype that are used to gauge the maturation state of RPE cultures including tissue-specific protein expression, protein polarity, and pigmentation are described. An argument is made that RPE epithelial phenotype, cadherin-based cell-cell adhesion and melanization are linked by a common signaling pathway: the Wnt/beta-catenin pathway. Analyzing this pathway and its intersecting signaling networks is suggested as a useful framework for dissecting the steps in RPE morphogenesis. Also discussed is the effect of aging on RPE phenotype. Preliminary evidence is provided to suggest that light-induced sub-lethal oxidative stress to cultured ARPE-19 cells impairs organelle motility. Organelle translocation, which is mediated by stress-susceptible cytoskeletal scaffolds, is an essential process in cell phenotype development and retention. The observation of impaired organelle motility therefore raises the possibility that low levels of stress, which are believed to accompany RPE aging, may produce subtle disruptions of cell phenotype. Over time these would be expected to diminish the support functions performed by the RPE on behalf of photoreceptors, theoretically contributing to aging retinal disease such as age-related macular degeneration (AMD). Analyzing sub-lethal stress that produces declines in RPE functional efficiency rather than overt cell death is suggested as a useful future direction for understanding the effects of age on RPE organization and physiology. As for phenotype and pigmentation, a role for the Wnt/beta-catenin pathway is also suggested in regulating the RPE response to oxidative stress. Exploration of this pathway in the RPE therefore may provide a unifying strategy for advancing our understanding of both RPE phenotype and the consequences of mild oxidative stress on RPE structure and function.
Collapse
Affiliation(s)
- Janice M Burke
- Department of Ophthalmology, Medical College of Wisconsin, The Eye Institute, 925 North 87th Street, Milwaukee, WI 53226-4812, USA.
| |
Collapse
|