STZ-induced diabetes in hyperlipidemic Apoe−/− mice, on the other hand, resulted in a 2.1-fold increase in OPN mRNA in retinal vessels, 8 weeks after the first STZ injection (Supplementary Figure 4(c)), highlighting potential differences in the regulation of OPN depending on mice strain, duration of diabetes, and/or blood lipid levels. This evidence concerns the gene APOE and diabetes mellitus.