Fig. 5

Involvement of complement in the induction of antifibrinolytic activity in vascular endothelial cells. Porcine aortic endothelial cells were grown to confluence in autologous porcine serum. Transgenic porcine aortic endothelial cells that expressed human CD59 and DAF were grown to confluence in 10% FCS as a control medium. The cells were then stimulated with 20% human serum or control medium for times up to 24 hr. The cells were then stimulated with 20% human serum or control medium for times up to 24 hr. The serum was removed and the endothelial cells were incubated with serum-free medium for 24 hr. This conditioned medium was then harvested and assayed for fibrinolytic and antifibrinolytic activity. Wild-type porcine endothelial cells exhibited an increase in antifibrinolytic activity when stimulated with 20% human serum. Transgenic porcine endothelial cells did not have increased antifibrinolytic activity when stimulated with 20% human serum verses the control medium. These findings suggest that complement activation is the impetus that induces antifibrinolytic changes. Circles, wild-type porcine endothelial cells stimulated with human serum; diamonds, transgenic porcine endothelial cells stimulated with human serum; squares, transgenic porcine endothelial cells incubated with control FCS.