CULTURED HUMAN ENDOTHELIAL-CELLS SEEDED ON EXPANDED POLYTETRAFLUOROETHYLENE SUPPORT THROMBIN-MEDIATED ACTIVATION OF PROTEIN-C

Purpose: Reduction of the thrombogenicity of synthetic vascular grafts by endothelialization has been suggested. The purpose of this study w as to examine some of the nonthrombogenic properties of cultured adult human great saphenous vein endothelial cells seeded on expanded polyt etrafluoroethylene (ePTFE) grafts. Methods: Endothelialized grafts, co ntrol grafts, and wells were incubated with thrombin. Assays of thromb in loss from solution, thrombin coagulant activity and protein C activ ation on the surface were obtained. The presence of thrombomodulin was confirmed with immunohistochemistry. Results: Significantly more thro mbin was found on the ePTEE grafts or wells that underwent endothelial ization, and larger amounts were lost from the thrombin solution compa red with the control group. Thrombin enzyme activity on the endothelia lization group was almost completely represented by activation of prot ein C and only to a minor extent by activity towards fibrinogen. Concl usions: It is concluded that endothelial cells seeded on ePTFE retain the possibility to inhibit thrombin coagulant activity and to activate protein C. These findings provide support for the clinical applicabil ity of cultured autologous endothelium on ePTFE grafts.