Up-regulation of thrombomodulin is inducible on an endothelialized polyester

The concept of endothelial cell seeding of vascular prostheses is designed as a method for improving long-term patency substitutes because endothelium is considered as the haemocompatible surface of reference. The assessment of the functionality of cells lining a biomaterial is thus of crucial importance. We have reported encouraging results concerning the ability of a polyester coated with albumin and chitosan (M 11) to be lined by a confluent monolayer of cultured human endothelial cells (EC). The aim of the present work was to study the expression of thrombomodulin (membrane glycoprotein responsible for anticoagulant activity) in EC lying on M.11 by anticoagulant activity and mRNA level with and without stimulation. Results obtained in basal conditions showed that EC on M.11 have a comparable expression of TM mRNA when compared to control (EC on tissue culture plates) despite a lower TM surface activity for EC on the biomaterial. In terms of ratio (stimulated cells to unstimulated ones) the response in activity for EC on M.11 is comparable to that of the control. These results indicate that cells lying on M.11 are able to respond to physiological-like stimuli, despite a tendency for these cells to express a procoagulant phenotype when compared with control EC.