(A) TF is constitutively expressed by vascular smooth muscle cells (VSMCs) and activated monocytes and ECs. PON2 is expressed by macrophages, VSMCs, and ECs. (B) Loss of PON2 leads to increased levels of reactive oxygen species (ROS) in ECs and de-encryption of TF. In addition, increased levels of ROS may induce TF gene expression. Increased levels of EC TF activity are proposed to mediate the prothrombotic state in PON2^−/− mice, which was assessed by measuring plasma FVIII, FIX, and FXI activities, prothrombin time (PT), activated partial thromboplastin time (aPTT), and tail bleeding. The antioxidant N-acetylcysteine (NAC) and an anti-mouse antibody (Ab) normalize the prothrombotic state in PON2^−/− mice. KO, knockout.