REN and hypertensive disorder: A variety of factors may be involved in the causes of hypertension, such as the interaction of environment and heredity factors leading to disturbances of blood pressure regulation, the pathological mechanism of which includes the sympathetic nervous system, renin-angiotensin-aldosterone system (RAAS), vasopressin, nitric oxide (NO), endothelin (ET), and a variety of vasoactive peptides secreted by other endothelial cells and smooth muscle cells (Sakao et al., 2009; Berger et al., 2009).