THROMBI FORMED IN A CHANDLER LOOP MIMIC HUMAN ARTERIAL THROMBI IN STRUCTURE AND PAI-1 CONTENT AND DISTRIBUTION

We have previously shown that whole blood clots prepared under static conditions are a poor model for human thrombi farmed in vivo. The most striking contrast is in the PAI-1 content, some 100 times rower in st atic clots than in human thrombi. This study aimed to evaluate thrombi formed in an artificial circulation (Chandler loop) using whole blood augmented with platelets. Citrated blood was recalcified and placed i n tubing, which was sealed to form a closed loop and circulated. Immun ohistochemical staining revealed morphology very similar to human thro mbi formed in vivo, comprising dense platelet-rich heads and fibrin-ri ch tails. Strong positive staining for PAI-1 was observed in fibrin-ri ch areas of both the head and the tail. The PAI-1 content of the throm bi increased significantly on augmentation of blood with isolated plat elets, and reached levers comparable with those in human thrombi. Thes e Chandler thrombi thus provide an appropriate model system for the st udy of thrombus lysis, in contrast to static brood clots.