RAC1 and diabetic retinopathy: 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.