TNF and macular retinal edema: Besides, it has been reported by Bucolo et al. that the up-regulation of proinflammatory factors and angiogenic parameters, such as tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF), intercellular adhesion molecule-1 (ICAM-1) and interleukin-1β (IL-1β), contribute to the blood–retinal barrier (BRB) breakdown, which directly leads to macular edema in DR [12,13,14,15].