NOX4 and diabetic retinopathy: In addition to Nox2, other members of the Nox family, specifically Nox1 and Nox4, are also involved in cellular dysfunction leading to pathological conditions, and altered activities of Nox1, Nox2 and Nox4 are seen in specific retinal cell types including endothelial cells and pericytes, in diabetes, implicating them in the development and progression of diabetic retinopathy [15,21,22].