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Magdalena M Olchawa, Justyna Furso, Grzegorz Szewczyk, Anna K Pilat, Tadeusz J Sarna; Inhibition of phagocytic activity of ARPE-19 cells induced by lipofuscin mediated photic stress - effects of donor’s age and antioxidants.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):6547.
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© ARVO (1962-2015); The Authors (2016-present)
It is believed that accumulation of lipofuscin granules (LFG) in the aging retinal pigment epithelium (RPE) may increase the susceptibility of the cells to photic stress and could play a role in pathogenesis of age related macular degeneration (ARMD). In this study we tested if sub-lethal oxidative stress induced by irradiation of ARPE-19 cells containing phagocytized LFG isolated from donors of different age affected the cell phagocytic activity and whether combination of selected antioxidants could modify the observed outcomes by changing phototoxic potential of lipofuscin.
ARPE-19 cells pre-loaded with LFG, isolated from human RPEs from donors of different age or containing LFG enriched with a combination of zeaxanthin and α-tocopherol (LFG-A) were irradiated with blue light for selected time intervals to produce sub-lethal damage in cells. The specific phagocytosis of FITC-labeled POS isolated from bovine retinas was analyzed by flow cytometry 5.5 h after or 24 h after light irradiation. Photoreactivity of LFG and LFG-A was analyzed by measuring oxygen photo-consumption and by photo-generation of superoxide anion employing electron paramagnetic resonance (EPR) oximetry and spin trapping.
Sub-lethal irradiation or ARPE-19 cells containing phagocytized LFG with blue light induced marked inhibition of the specific phagocytosis of POS with the effect being substantially stronger for LFG obtained from older donors (50-59 y/o) compared to younger donors (18-29 y/o). The inhibitory effect of LFG was significantly reduced by their enrichment with combination of antioxidants. The observed rates of photo-induced oxygen uptake and accumulation of superoxide spin adduct indicated that aerobic photoreactivity of lipofuscin increased with donor’s age and decreased after enrichment with antioxidants.
Although phototoxic potential of LFG increases with aging and could contribute to impairment of phagocytic activity of the aged RPE, natural antioxidants such as zeaxanthin and α-tocopherol might help to retain this important RPE function by reducing lipofuscin photoreactivity.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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