NOX4 and diabetic retinopathy: NOX4 seems to protect vascular endothelial dysfunction from ischemic and hypoxic stresses, inhibit vascular inflammation and promote physiological angiogenesis during tissue revascularization, except in the models of OIR and diabetic retinopathy where NOX4 contributes to pathologic intravitreal neovascularization and diabetic retinopathy.