“…Several serum/plasma factors including VEGF, 145,163,198,223,300,303,427 bilirubin, 96,113,134,169,178,201,258,416 sE-selectin, 66,304 CRP, 186 apelin, 16 vitamin D, 194 trace elements such as zinc, 407 and inflammatory cytokines such as IL-6 350 have been studied. Although VEGF is a key factor in retinal angiogenesis, studies on systemic levels of VEGF and related factors such as soluble VEGF receptors showed contradictory results.…”