Inhibition of Xa-induced MMP-2 by TFPI in VSMCs. Cell-associated (A) and secreted (B) MMP-2 expression was determined by immunoassay in untreated (□) and factor Xa–stimulated, untransfected (▪) VSMCs, and Ad5TFPI-transfected (▧) and Ad5lacZ-transfected (▦) VSMCs. Data are mean ± SEM of 3 experiments. #P < .05, **P < .001. MMP-2 activity of untransfected (lanes 2 and 4) and TFPI-transfected (lanes 1 and 3) rabbit VSMCs was determined after stimulation with factor Xa (lanes 3-4) by gelatin zymography (C).