Effects of Crude Fucus distichus Subspecies evanescens Fucoidan Extract on Retinal Pigment Epithelium Cells-Implications for Use in Age-Related Macular Degeneration.

Fucoidan extracts may have beneficial effects in age-related macular degeneration(AMD). Over-the-counter fucoidan preparations are generally undefined, crude extracts. In thisstudy, we investigated the effect of a crude fucoidan extract from Fucus distichus subspeciesevanescens (Fe) on the retinal pigment epithelium (RPE). Fe extract was investigated for chemicalcomposition and molar mass. It was tested in primary RPE and RPE cell line ARPE19. Oxidativestress was induced with tert-butyl hydroperoxide, cell viability evaluated with MTT assay, VEGFsecretion assessed in ELISA. Phagocytosis was evaluated in a fluorescence microscopic assay.Wound healing ability was tested in a scratch assay. Additionally, the inhibition of elastase andcomplement system by Fe extract was studied. The Fe extract contained about 61.9% fucose andhigh amounts of uronic acids (26.2%). The sulfate content was not as high as expected (6.9%). It wasnot toxic and not protective against oxidative stress. However, Fe extract was able to reduce VEGFsecretion in ARPE19. Phagocytosis was also reduced. Concerning wound healing, a delay could beobserved in higher concentrations. While some beneficial effects could be found, it seems tointerfere with RPE function, which may reduce its beneficial effects in AMD treatment.