REN and heart failure: Angiotensin II (Ang II), the major bioactive peptide product of the renin–angiotensin–aldosterone system, has been extensively demonstrated to be a key player in the pathological development of cardiovascular morphology and function via altering systemic inflammatory response, blood pressure, cardiac hypertrophy, interstitial collagen deposition and tissue fibrosis, which lead to vascular dysfunction and heart failure [8].