Although VEGF antagonists can prevent the angiogenesis of wet AMD, studies in other systems such as skeletal muscle splitting vessels have found that PDGF-BB limits the extent of vascular expansion by regulating VEGFR2 signaling and endothelial cell proliferation to prevent VEGF-induced abnormal angiogenesis, thus enabling the vessels to effectively split into a normal capillary network, with PDGF-BB seemingly playing a protective role (40). This evidence concerns the gene KDR and wet macular degeneration.