KDR and diabetic retinopathy: Importantly, an abnormal vascular permeability is also involved in other pathologies including diabetic retinopathy [60], neurological disorders [61], and lung injury [62] and, interestingly, besides the VEGF/VEGFR2 system [63, 64], the Eph/ephrin system is also involved in the regulation of vascular permeability [6, 65, 66].