Fatty acids and oxidized lipoproteins contribute to autophagy and innate immunity responses upon the degeneration of retinal pigment epithelium and development of age-related macular degeneration

Abstract

Retinal pigment epithelium (RPE) damage is a primary sign in the development of age-related macular degeneration (AMD) the leading cause of blindness in western countries. RPE cells are exposed to chronic oxidative stress due to constant light exposure, active fatty acid metabolism and high oxygen consumption. RPE cells phagocytosize lipid rich photoreceptor outer segment (POS) which is regulated by circadian rhytmn. Docosahexaenoic acid is present in high quantity in POS and increases oxidative stress, while its metabolites have cytoprotective effects in RPE. During RPE aging, reactive oxygen species and oxidized lipoproteins are considered to be major causes of disturbed autophagy clearance that lead to chronic innate immunity response involved in NOD-Like, Toll-Like, Advanced Glycation End product Receptors (NLRP, TLR, RAGE, respectively), pentraxins and complement systems. We discuss role of fatty acids and lipoproteins in the degeneration of RPE and development of AMD.

Keywords: Aging; Autophagy; Degeneration; Fatty acids; Inflammation; Macula; Oxidative stress.