VEGFA and Abnormal retinal morphology: What’s more, the analogues of long-acting FGF21 have recently been found to improve the permeability of tight junctions by increasing the level of tight junction proteins for example Claudin-1 in human vascular endothelial growth factor (VEGF)-induced human retinal microvascular endothelial cells and C57BL/6J mice, leading to the reduction of vascular leakage in retinal diseases (Tomita et al., 2020b).