Vitamin C suppresses lipopolysaccharide-induced procoagulant response of human monocyte-derived macrophages

OBJECTIVE: Although vitamin C is a strong antioxidant, the epidemiologic evidence to support its role in lowering risk of cardiovascular disease is inconsistent. In order to define the role of vitamin C in vascular pathophysiology, we have investigated the effect of vitamin C on the tissue factor (TF) and Factor VII Activating Protease (FSAP) expression induced by lipopolysaccharide (LPS) in human monocyte-derived macrophages. MATERIALS AND METHODS: Vitamin C at clinically relevant doses was tested to its ability to influence the LPS-and reactive oxygen species (ROS) - generating system of xanthine/xanthine oxidase (X/XO) NF-kappa B activity in human monocyte-derived macrophages. RESULTS: Vitamin C-treatment prevents LPS- and ROS-induced DNA-binding activity of NF-kappa B in a concentration-dependent fashion. Vitamin C also inhibited the phosphorylation and proteolytic degradation of the inhibitor protein I kappa Ba. In parallel to regulate NF-kappa B activity, vitamin C reduced the expression of TF and FSAP, genes known to be induced by bacterial LPS and triggered the extrinsic coagulation cascade and linked thrombosis with inflammation. CONCLUSIONS: Vitamin C alters pro-inflammatory and pro-coagulatory processes via inhibition of NF-kappa B activation and exerts beneficial antiatherogenic effects on human monocyte-derived macrophages in addition to its anti-oxidant properties.