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Natalia Vila, Patrick T Logan, Vasco Bravo-Filho, Nathaniel Young, Pablo Zoroquiain, Miguel N Burnier, Henry C. Witelson Ocular Pathology Laboratory; Blue light filters prevent light-induced angiogenic factor secretion by retinal pigmented epithelial cells . Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3386.
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© ARVO (1962-2015); The Authors (2016-present)
Retinal pigmented epithelium (RPE) phototoxicity is a risk factor for age-related macular degeneration (ARMD) and blue light exposure is toxic to RPE cells. The increased production of angiogenic factors secondary to light exposure may play a role in ARMD. In the present study, pro-angiogenic factor secretion by RPE cells under various conditions was assessed.
A human RPE cell line (ARPE-19) was used for all experiments. Five experiments were performed exposing cells to light (LED light source, 9,000 lux) for 48 hours with and without a blue light-filter (BLF) under different conditions. One group was exposed to hypoxia (1% O2) and a second group was cultured with 1 μg/ml lutein to simulate ARMD treatment conditions, both for 24 hours before being exposed to light. Media from all groups was harvested for sandwich ELISA-based angiogenesis assays. The secretion of 10 pro-angiogenic cytokines was measured: angiogenin, ANG2, EGF, bFGF, HB-EGF, PDGF-BB, Leptin, PIGF, HGF, and VEGF-A. The trypan blue exclusion test was used to determine cell viability. A two-way ANOVA was performed to compare the levels of these factors between groups.
VEGF, EGF, and bFGF secretion increased in the light exposure group compared to controls (P<0.05). Viability was significantly greater in the BLF group (P<0.05). No differences in VEGF secretion between BLF and the control group was found (P=0.364). When the cells were exposed to hypoxia and light, EGF, bFGF, Hb-EGF, PIGF, and VEGF were higher than the control group (P<0.05), but when a BLF was used, these increases were not significant (P>0.05), except for PIGF (P=0.04). The group treated with lutein and protected by the BLF showed lower levels of VEGF than the unfiltered group (P<0.05).
Light exposure increases pro-angiogenic factors in RPE cells, which are involved in ARMD. BLFs attenuate the cellular secretion of some of these factors. In addition, cell viability increases when blue light is filtered. Light exposure increases VEGF secretion; protection with a BLF can maintain secretion within normal levels, even with concomitant stressors like hypoxia, or when there is lutein uptake by the cells. These conditions, hypoxia and lutein uptake, simulate the environment in which RPE cells are exposed to in dry ARMD.
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