REN and chronic kidney disease: The beneficial effects of renin-angiotensin system (RAS) inhibition with angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs) have been demonstrated in hypertensive patients with high cardiovascular-renal risks including heart failure [1], myocardial infarction [2], diabetes [3] and chronic kidney disease (CKD) [4].