Abstract
Dihydropyridine-based calcium antagonists (DHPs) are widely used to treat hypertension. We have previously shown that nifedipine, one of the most popular DHPs, blocks tumour necrosis factor-α (TNF-α)-induced monocyte chemoattractant protein-1 as well as vascular cell adhesion molecule-1 (VCAM-1) expression in endothelial cells by suppressing reactive oxygen species generation (ROS). The molecular mechanism is still to be elucidated, however, because endothelial cells do not possess voltage-operated L-type calcium channels. The aim of this study was to determine in TNF-α-exposed human umbilical vein endothelial cells (HUVECs) whether and how Bay w 9798, a dihydropyridine structurally related to nifedipine with no calcium antagonistic properties, may suppress VCAM-1 expression, a key molecule which mediates the adhesion of monocytes to vasculature in the early stages of atherosclerosis. In HUVECs, 10 ng/ml TNF-α for 4 h stimulated ROS generation and subsequently upregulated VCAM-1 mRNA levels, both of which were dose-dependently blocked by Bay w 9798. The results demonstrated that Bay w 9798 inhibited VCAM-1 expression in TNF-α-exposed cells by suppressing ROS generation. They suggest that the anti-inflammatory and anti-oxidative properties of nifedipine and Bay w 9798 may be ascribed to the dihydropyridine structure, which is common to both molecules and has no calcium antagonistic ability.