Several processes including endothelial angiogenesis, vascular neointimal lesion formation, vascular
inflammation process, lipoprotein metabolism, and hypertension are critically involved in atherosclerosis. This
chapter aims to introduce the role of miRNAs in hypertension. Angiotensin II, the major bioactive peptide of the
renin–angiotensin system, plays a crucial role in controlling various cardiovascular diseases, especially
hypertension. Endothelium-dependent nitric oxide (NO) formation has been reproducibly demonstrated to be
reduced in patients with essential hypertension compared with normotensive control subjects. Formation of NO in
endothelial cells depends on an adequate and continuing supply of its key substrate, L-arginine. Studies on
miRNAs in hypertension have been rather sparse, though miRNAs have been reported to play a role in
hypertension. In particular, miR-155 regulates angiotensin II type 1 receptor and miR-122 regulates L-arginine
transport.
