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Katharine Denius, Sally Yacout, Elizabeth R Gaillard; Biochemical study of L-DOPA supplements on Retinal Pigment Epithelial Cells. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3075. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
This study investigates the effects of 3,4-dihydroxy-L-phenylalanine (L-DOPA) on retinal pigment epithelial cells. L-DOPA is an intermediate of the melanin biosynthesis pathway, and studies have implicated it may have beneficial effects in attenuating and treating pathologic changes to the retina. This study investigates in vitro effects of L-DOPA supplements to unpigmented human retinal pigment epithelial cells and explores the potential of a liposomal drug delivery system.
ARPE-19 cells were used in this study. Cells were subjected to UV-C irradiation or dark treatment and were then fed L-DOPA or liposome encapsulated L-DOPA. Vehicle controls and buffer encapsulated liposomes were used as controls. Cell viability was monitored using MTT assay for a period of 1, 3, or 5 days. L-DOPA oxidation products were separated using LC/MS and products were used in previously described experiment in comparison to L-DOPA and a vehicle control. Lysosome membrane permeability was assessed using acridine orange dye and intracellular fluorescence was measured using flow cytometry. For this assay, cells were fed L-DOPA, L-DOPA oxidation products, or vehicle control. Statistical analysis was done using a one-way or two-way ANOVA.
An increase in cell viability was observed in L-DOPA encapsulated liposome fed cells treated with UV-C on days 3 and 5 versus cells fed L-DOPA directly in media (88±12% and 74±14%). Oxidation product fed cells showed no significant increase in cell viability versus control cells with either dark or UV-C treatment, however a significant increase in viability was observed in L-DOPA fed cells versus control in both treatment groups (p < 0.0001). Lysosome membrane permeability significantly increased in cells fed L-DOPA oxidation products versus control cells and L-DOPA fed cells (p < 0.001, p < 0.01).
Our evidence suggests that liposomal encapsulation of L-DOPA increases the overall viability of stressed cells. L-DOPA oxidation products provide no significant benefit to photo-stressed RPE cells and promote lysosome membrane permeability in RPE cells.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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