RHO and diabetic retinopathy: Several signaling pathways, including PKC, vascular endothelial growth factor (VEGF), nuclear factor erythroid 2-related factor 2 (Nrf2), and Rho/Rho-associated coiled-coil containing protein kinase (Rho/ROCK), have been implicated in carotenoid-mediated protection of the retina in diabetic retinopathy [81].