Despite the known benefits of ACEi/ARB in improving cardiovascular and renal outcomes, it is important to remark that it has also been demonstrated that renin cells can lead to renal arteriolar hypertrophy that is indistinguishable from that observed in uncontrolled hypertension when these cells are chronically stimulated by RAAS gene mutations or by the use of RAASi in humans and other mammals. This evidence concerns the gene REN and Hypertension.