The influence of blood flow to the thrombus formation was analyzed using hybrid vascular model (HVM). HVM was made by silica glass and endothrialization was performed. HVM was implanted into femoral artery and vein of mongrel dog respectively. HVM from artery was not recognized thrombus formation. Minimal platelets adhesion was observed by scanning electron micro scope (SEM) (Fig. 1). In contrast, line shaped thrombus was observed on the inferior area of the venous specimen (Fig. 2). Different flow patterm, artery and vein, effect the different shesr stress on the vessel wall. Those findings suggested that diminution of shear stress induced the thrombus initiation in vein.
Pathological changes of vessels, i, e. aneurysm and stenosis, are influenced to thrombus formation in clinical experience. Pathological model, eccentric dilatation or stenosis in the center of the tube, were connected to
in vitro flow visualizing system. Flow pattern through the model was recorded by video (Fig. 3). Significant flow stagnation was observed in dilatation and just after stenosis (Fig. 4). Pathological HVM (D-HVM and S-HVM) were implanted into femoral arteries. The specimen demonstrated that thrombus was located the same area of the flow stagnation
in vitro (Fig. 5). Those results surmised that flow stagnation related with thrombus formation.
Owing to estmate the thrombin production on the endothelial cell (EC), HVM was incubated with thrombomodulin monochronal antibody (TMmAb20: Mitsubishi Gas Chemical). HVM was implanted into femoral vein. Immediate thrombus formation was occurred and obvious fibrin network on the EC was observed (Fig. 7). This finding suggested hat the thrombin was produced on the EC in physiologically. However, thrombomodulin on the EC affected with thrombin and thrombin was altered non-active form in physiological flow. This finding suspected that the flow stagnation would diminish the clearance of thrombin on the EC.
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