Similar effect of inhibition of SPT on Rac1–Nox2–ROS signaling, and on Rac1 transcriptional activation, obtained in retinal microvasculature from type 1 (Diab) and type 2 (HF-SD) diabetic animal models, the two models that develop vascular histopathology characteristic of diabetic retinopathy7,21, further strengthen the role of ceramides in ROS generation in the early stages of diabetic retinopathy. This evidence concerns the gene AGXT and diabetic retinopathy.