REDUCTION OF MONOCYTE ADHESION TO XENOGENEIC TISSUE BY ENDOTHELIALIZATION - AN ADHESION MOLECULE AND TIME-DEPENDENT MECHANISM

Great interest has been shown for the seeding of autologous endothelia l cells on prosthetic materials, We investigated the inflammatory and immunogenic properties of xenogeneic tissue before and after seeding w ith cultured human great saphenous vein endothelial cells in vitro. Ad hesion of monocytes to xenogeneic tissue with or without endothelium a nd the endothelial cell expression of E-selectin, intercellular adhesi on molecule 1, vascular adhesion molecule 1, and major histocompatibil ity complex class II antigens were investigated 1, 3, and 7 days after seeding, Both monocyte adhesion and endothelial adhesion molecule exp ression were relatively high 1 day after seeding and were significantl y lowered after 3 to 7 days. There was no difference between monocyte adhesion and adhesion molecule expression on viable or nonviable xenog eneic tissue. Monocyte adhesion and adhesion molecule expression incre ased after interleukin-1 beta or interferon-gamma stimulation of the e ndothelial cells. The results suggest that human endothelial cells exh ibit an early proinflammatory and immunogenic activity immediately aft er seeding, Three and 7 days after seeding, the endothelialized surfac e is less adhesive for monocytes as compared with nonendothelialized t issue. These findings have implications when cultured or intraoperativ ely recruited endothelial cells are used clinically.