Vitamin C is additive to statin in improving the endothelial function in hypercholesterolemic patients

On, Young Keun; Sung, Ji Dong; Chae, In Ho; Kim, Cheol Ho; Sohn, Dae Won; Oh, Byung Hee; Lee, Myoung Mook; Park, Young Bae; Choi, Yun Shik

Abstract

BACKGROUND: Hypercholesterolemia is firmly established as a risk factor for the development of atherosclerosis. However the exact mechanism of hypercholesterolemia-related damage to the arterial wall and its relation to the atherosclerotic process are not well known. The endothelium plays an important role for the regulation of vascular tone and the endothelial function is impaired in the presence of risk factors early in the process of atherosclerosis. Assessment of endothelial function appears to be a valuable tool for the diagnosing and therapeutic monitoring of coronary artery disease. Lipid lowering agents and anti-oxidants are known to improve endothelial dysfunction in hypercholesterolemic patients, respectively. The purpose of this study is to investigate whether vitamin C has additional benefit on endothelial function of statin-treated hypercholesterolemic patients.
METHODS
The endothelial function was estimated using venous occlusion plethysmography (VOP) in 9 hypercholesterolemic patients and 11 healthy volunteers. The strain guage was connected to plethysmograph to record the forearm volume change. A rapid cuff inflator was used to inflate the arm cuff to 40 mmHg instantaneuosly thus occluding venous return from the forearm. The measurement of forearm volume change was repeated for 7 times each stage. The patients in the hypercholesterolemic (HC) group were treated with the statin, then examined again. The change of the forearm blood flow (FBF) was measured with the acetylcholine infusion through brachial artery and also with intra-arterial vitamin C.
RESULTS
Endothelium-dependent vasodilatation was significantly impaired in the HC group compared to the control group (15.9+/-0.9 mL/min/100mL forearm tissue, vs 8.9+/-0.6 mL/min/100mL forearm tissue, mean+/-standard error of mean, p<0.05). The FBF increased significantly after statin therapy (8.9+/-0.6 vs 25.2+/-1.4 mL/min/100mg forearm tissue, p<0.05). Vitamin C infusion in these patients results in additional improvement in FBF (25.2+/-1.4 vs 31.9+/-2.1, p<0.05).
CONCLUSION
Endothelium-dependent vasodilatation was significantly impaired in the HC group compared to the control group. The FBF increased significantly after statin therapy. Vitamin C seems to have additional benefit on the endothelial function of statin-treated hypercholesterolemic patients.