Proliferation of endothelial cells on surface-immobilized albumin-heparin conjugate loaded with basic fibroblast growth factor

Seeding of endothelial cells (ECs) on the luminal surface of small-diameter vascular grafts is a promising method to avoid occlusion of these prosthes es. Immobilization of basic fibroblast growth factor (bFGF) to substrates u sed to coat or fill porous prostheses may enhance the formation of a conflu ent monolayer of ECs. Human umbilical vein endothelial cells (HUVECs) were grown on bFGF-loaded albumin-heparin conjugate bound to CO2 gas-plasma-trea ted polystyrene. In the order of 2-3 ng/cm(2) bFGF had to be immobilized to form a confluent monolayer of HUVECs. The most prominent effect of surface -immobilized bFGF was stimulation of the proliferation shortly after seedin g, resulting within 3 days in confluent cell monolayers with high density. In contrast, in cultures with 0.3 ng/mL bFGF in the medium instead of bFGF bound to the surface, it took almost a week before the cell layers reached confluency. Binding of bFGF to heparin and the biological activity of bFGF towards ECs were not influenced by the (radio-)labeling of bFGF with iodine . However, only a minor part of the bFGF used in this study displayed hepar in affinity. Furthermore, degradation and multimerization of labeled bFGF i n time occurred when the growth factor was stored at 20 degrees-37 degrees C. This Limits the use of labeled bFGF to short-term (hours) experiments. I n conclusion, bFGF loading of vascular graft surfaces through complexation of bFGF with a heparin-containing matrix probably will lead to more rapid f ormation of a confluent monolayer of ECs on graft surfaces upon seeding of the cells. (C) 1999 John Wiley & Sons, Inc.