For validating the role of the APP gene in the risk of AD, we developed PDR in a mouse model with STZ-induced T1DM (Figure 10A), in which the blood–retina barrier permeability was enhanced (Figure 10B) and the number of acellular vessels (Figure 10C) and microaneurysms (Figure 10D) increased in the retinal microvasculature. Here, APP is linked to type 1 diabetes mellitus.