Combination therapy of amlodipine and atorvastatin has more beneficial vascular effects than monotherapy in salt-sensitive hypertension

BACKGROUND Current treatment for the secondary prevention of cardiovascular diseases frequently involves the prescription of several combination therapies, particularly antihypertensive medications and HMG-CoA reductase inhibitor. We have previously shown that in salt-sensitive hypertension either a statin or the calcium channel blocker amlodipine (Aml) have vasoprotective effects. Here, we investigated in aortas from Dahl salt-sensitive (DS) rats the effects of Aml, the statin atorvastatin (AT), and their combination on endothelial function, superoxide (O₂ ^-) production, and the expression of endothelial nitric oxide synthase (eNOS), chemokine monocyte chemoattractant protein-1 (MCP-1), and lectin-like oxidized LDL receptor-1 (LOX-1). METHODS Groups of DS rats were fed either normal-salt (NS, 0.5% NaCl) or high-salt (HS, 4% NaCl) diet or a HS diet with AT (15mg/kg/day), Aml (5mg/kg/day) or combination of AT/Aml for 6 weeks. RESULTS Rats on the HS diet developed hypertension, aortic hypertrophy, accompanied by increased plasma C-reactive protein (CRP), aortic O₂ ^-, MCP-1 (80%), and LOX-1 (55%) expression and reduced eNOS and endothelial-dependent relaxation to acetylcholine (EDR). Aml reduced systolic blood pressure (SBP), aortic hypertrophy, plasma CRP, vascular O₂ ^-, and MCP-1 expression and improved eNOS and EDR. AT reduced aortic hypertrophy and plasma CRP, improved EDR, and normalized vascular O₂ ^-, eNOS, and proinflammatory gene expression with mild reduction in SBP. Combination therapy further reduced the SBP and normalized aortic hypertrophy, EDR, and plasma CRP. CONCLUSIONS The combination therapy of Aml/AT has an additive beneficial effect on the vasculature. These novel findings may provide scientific basis for the combination therapy of statins with antihypertensive agents to reduce and prevent cardiovascular diseases.