Effects of L-/N-Type Calcium Channel Blockers on Angiotensin II-Renin Feedback in Hypertensive Patients

Objectives. Cilnidipine, an L-/N-type calcium channel blocker (CCB), has unique organ-protective properties due to suppression of hyperactivity in the sympathetic nervous system and renin-angiotensin system (RAS). In this study, we hypothesized that cilnidipine might exert a renoprotective effect by suppressing the RAS. Methods. A total of 25 hypertensive patients receiving a RAS inhibitor were randomly assigned to a cilnidipine (n = 12) or amlodipine (n = 13) group. The effects of cilnidipine on proteinuria and angiotensin II-renin feedback were assessed. Results. After 6 months of treatment, both systolic and diastolic blood pressures were significantly reduced to a similar extent in both groups. The urine albumin-to-creatinine ratio was significantly lower in the cilnidipine group (p<0.05) than in the amlodipine group. Amlodipine increased plasma angiotensin I and angiotensin II levels (p<0.05), whereas cilnidipine did not. Interestingly, the cilnidipine group had a higher ratio of angiotensin-(1-7) (Ang-(1-7)) to angiotensin II in plasma than the amlodipine group (p<0.05). Conclusions. The L-/N-type CCB cilnidipine, but not amlodipine, decreased urinary albumin excretion in hypertensive patients. Cilnidipine also increased the ratio of Ang-(1-7) to angiotensin II in plasma, which might be one factor underlying its beneficial effects.