An important observation was seen in the Nox4KO study group, where EC-NOX5 expression showed increased mesangial expansion, glomerulosclerosis, and enhanced glomerular accumulation of collagen IV as well as the upregulation of collagen IV and fibronectin not only in the presence of diabetes but also in the absence of diabetes, suggesting a dominant direct role of NOX5 in promoting pro-fibrotic pathways. Here, NOX5 is linked to glomerulosclerosis.