Loss of endothelial planar cell polarity and cellular clearance mechanisms in age-related macular degeneration.

Apoptosis, autophagosomes, and lysosomes are lacking in the retinal pigment epithelium (RPE) of age-related macular degeneration (AMD) eyes. Necrosis, not apoptosis, appeared to be the prominent type of cell death in RPE, which led to the accumulation of cell debris within and on both sides of Bruch's membrane. The endothelium of the choriocapillaris had an altered planar cell polarity which encompassed the disappearance of fenestrations, the thickening of cytoplasm, and anterior nuclear dislocation. There were no significant differences in RPE and choroidal aberrations between macular and temporal regions. Loss of endothelial polarity could be at the crux of AMD initiation and progression.