APOE and diabetic retinopathy: Given that pericyte deficiency or dysfunction is associated with a number of central nervous system disorders, including diabetic retinopathy [59] and neurodegenerative disorders such as AD [60], these findings [53], together with the studies on Aβ-ApoE effects on pericytes [18,23], make pericytes an interesting model for studying the influence of ApoE on IAPP-induced toxicity.