European Journal of Clinical Investigation Vol 38 106 DOI: 10.1111/j.1365-2362.2007.01911.x Blackwell Publishing Ltd ORIGINAL ARTICLES Statins inhibit HCY-induced VCAM-1 expression Statins inhibit HCY-induced VCAM-1 expression C. P. Lin et al. ORIGINAL ARTICLE Direct effect of statins on homocysteine-induced endothelial adhesiveness: potential impact to human atherosclerosis C. P. Lin *§ , Y. H. Chen *† , W. T. Lin § , H. B. Leu § , T. Z. Liu ‡ , S. L. Huang * and J. W. Chen *§ * National Yang-Ming University, Taipei; † China Medical University, Taichung; ‡ Chang Gung University, Taoyuan; § Taipei Veterans General Hospital, Taipei, Taiwan ABSTRACT Background Although homocysteine (HCY) is a risk factor for cardiovascular diseases, recent clinical trials failed to show the benefits by reducing plasma HCY. Alternative strategy with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, statins, might be feasible. This study investigated HCY-induced endothelial adhesiveness with mononuclear cells (MNCs) from patients with coronary artery disease (CAD). The direct endothelial protective effects of statins were also examined. Materials and methods Circulating MNCs were isolated from 14 stable CAD patients and 7 age- and gender-matched healthy subjects. Superoxide production of MNCs was determined by Ultra-weak and luminol-enhanced chemiluminescence. Human aortic endothelial cells (HAECs) were used for endothelial adhesiveness to MNCs or U937 human monocytic cells. Endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were examined by Western blot. Results Superoxide production of MNCs and plasma HCY and high-sensitive CRP levels were significantly increased in CAD patients than in healthy subjects. Stimulation with HCY enhanced the endothelial adhesiveness to MNCs from CAD patients or to U937 cells in a dose-dependent manner, whereas it was obscure with MNCs from healthy subjects. HCY stimulated endothelial VCAM-1 but not ICAM-1 expression in a dose-dependent manner. Monoclonal antibodies to VCAM-1 attenuated HCY-induced endothelial adhesiveness. Simvastatin or pravastatin significantly reduced HCY-induced VCAM-1 expression and endothelial adhesiveness to MNCs from CAD patients. Conclusion Circulating MNCs were activated in CAD patients, which was critical to HCY-induced endothelial adhesiveness. Statins could directly reduce HCY-induced endothelial-MNC adhesion via VCAM-1 inhibition, suggesting its potential implication in HCY-related atherosclerosis disease. Keywords Cell adhesion molecules, coronary artery disease, endothelial adhesiveness, homocysteine, mononuclear cells, statin. Eur J Clin Invest 2008; 38 (2): 106–116 Introduction Homocysteine (HCY), a sulfhydryl amino acid metabolite of methionine, has been recognized as an independent risk factor for atherosclerotic diseases since elevated plasma levels of HCY may predict future cardiovascular mortality in clinical settings [1,2]. Although reduction of plasma HCY might reduce cardiovascular events after coronary intervention [3], most of the recent trials failed to demonstrate favourable outcomes by lowing HCY concentration with B vitamins and folic acid, or both, in patients with various atherosclerotic diseases [4–7]. Although HCY was shown to enhance the endothelial adhesiveness to monocytes from healthy subjects, an in vitro sign of atherogenesis [8], further clinically related studies are required to clarify the pathological role of HCY in human atherosclerotic diseases. Besides, the alternative strategies other than HCY-lowering should focus on direct vascular protection in the presence of hyperhomocysteinaemia. Statins, the competitive inhibitors of 3-hydroxy-3- methylglutaryl coenzyme A (HMG-CoA) reductase, could provide extensive cardiovascular protection through both