NOX4 and Hypercholesterolemia: In another model of diastolic dysfunction induced by diet-induced hypercholesterolaemia, NOX4 was found to be up-regulated relative to NOX2 in the hearts of cholesterol-fed rats.74 Furthermore, myocardial microRNA-25 was found to be a direct target for NOX4 and was decreased in cholesterol-fed rat hearts, with in vitro studies demonstrating a direct link between reduced microRNA-25, increased NOX4 expression, and oxidative stress.