Effects of Paricalcitol and Enalapril on Atherosclerotic Injury in Mouse Aortas

Aims: This study investigated the protective effect of vitamin D analog paricalcitol combined with angiotensin-converting enzyme inhibitor (enalapril) on aortic oxidative injury in atherosclerotic mice.

Methods: Female mice were treated for 16 weeks as follows: (1) ApoE deficient + vehicle, (2) ApoE deficient + paricalcitol (200 ng 3 times a week), (3) ApoE deficient + enalapril (30 mg/l in drinking water), (4) ApoE deficient + paricalcitol + enalapril, and (5) wild-type controls.

Results: ApoE-deficient mice developed hypertension which was prevented by enalapril or enalapril + paricalcitol treatment but not by paricalcitol treatment. Histology showed atherosclerotic plaque in the aorta of ApoE-deficient mice which was prevented by paricalcitol, enalapril, and paricalcitol + enalapril treatments. Aortic malondialdehyde levels, NADPH oxidase subunit p22(phox), manganese-superoxide dismutase (Mn-SOD), inducible nitric oxide synthase, monocyte chemoattaractant protein-1, tumor necrosis factor (TNF)-α, and cyclooxygenase-2 protein expressions increased, whereas glutathione levels, CuZn-SOD, and endothelial protein expressions decreased in ApoE-deficient mice compared to controls. Treatment with paricalcitol and enalapril alone or in combination protected the inflammatory and oxidative endothelial injury of the aorta in atherosclerotic mice.

Conclusion: Combination therapy affords greater protection against aortic inflammatory and oxidative injury in atherosclerosis than monotherapy.