Amlodipine improves aortic dysfunction in atherosclerotic mice

Calcium channel blockers are established in treating hypertension or arrhythmias. They have also been suggested to have anti-atherosclerotic effects, although most such studies are limited mainly to histological or biochemical parameters. Therefore, the aim was to test the hypothesis that amlodipine (AMLO) improves vascular function in atherosclerosis in particular. Here, PCSK9DY-injected C57BL/6N-mice on a Western diet (WD) were orally treated with either AMLO (10 mg/kgbw) or vehicle (VEH), while controls received adeno-associated virus vector (AAV) and a chow diet. Pulse wave velocity (PWV) was measured in vivo by ultrasound. Cortical stiffness was determined ex vivo by atomic force microscopy and in vitro in endothelial cells. Compared to controls, plaque burden and calcification deposits in the thoracic aorta and plasma levels of lipids, TNFα, IL6, and NO were increased in PCSK9DY+WDVEH mice. Upon AMLO treatment, NO, calcification, and plaque burden were reduced, but not lipids. PWV (1.267 ± 0.232 vs. 0.908 ± 0.173 m/s) and cortical stiffness (1.412 ± 0.033 vs. 0.992 ± 0.015 pN/nm) were higher in the PCSK9DY+WDVEH than in AAV+chowVEH mice but remained almost normal despite PCSK9DY+WD intervention when treated with AMLO (0.987 ± 0.119 m/s or 1.181 ± 0.026 pN/nm). AMLO reduced PWV and stiffness in AAV+chow mice and decreased cortical stiffness and increased glycocalyx height in endothelial cells. We conclude that AMLO improves vascular function in atherosclerosis as PWV and cortical stiffness become normalized. Since AMLO also improved function in AAV+chow controls and in endothelial cells, we further conclude that the effect is independent of the development of atherosclerosis. Furthermore, our in vivo results point to a NO-dependent mechanism.