Functional Cardiovascular Effects of Angiotensin Peptides: Focus on Atherosclerosis and Hypertension

The renin-angiotensin system (RAS) is a major physiological regulator of body fluid volume, electrolyte balance, and arterial blood pressure. The octapeptide, angiotensin (Ang) II, is the main effector of the RAS and overactivity of Ang II is a major contributor to pathological changes in cardiovascular disease; exemplified by the vasoprotective effects observed with RAS inhibition that extend beyond blood pressure reduction. However, an emerging concept of the RAS is the unique roles of shorter peptide fragments other than Ang II, such as Ang (1-7), Ang III and Ang IV. These peptides were initially thought to be inactive breakdown products of Ang II; however, they are now recognized as active components of the RAS, often with their own unique biological profile. This review will focus on the cardiovascular functions of these and other newly-discovered Ang peptides. The effects of these peptides will be discussed in the context of their actions at a number of non-AT1 receptors and the likely interplay with RAS inhibition.