A significant decrease in the expression of platelet-derived growth factor receptor beta (PDGFRB), vascular endothelial growth factor A (VEGFA) and transforming growth factor beta 1 (TGFB1) in both primary RPE and RF/6A cells transfected with siPPARβ/δ, as compared to control siRNA (Figure 2, and D) suggests that disruption of PPARβ/δ expression in both of these AMD-vulnerable cells leads to an anti-angiogenic environment in the RPE and choroid. This evidence concerns the gene PDGFRB and age-related macular degeneration.