Cytokines that mainly seem to play a role in the development of retinopathy in DM are the pro-inflammatory cytokines interleukin-1β (IL-1β), IL-6, and tumor necrosis factor (TNF)-α, as well as the chemokine IL-8 as these are elevated in vitreous samples from PDR patients [7–11]. This evidence concerns the gene CXCL8 and diabetes mellitus.