Analysis of Protein Adsorption on Retrieved Human Vascular Grafts Using Immunogold Labelling with Silver Enhancement

The adsorption of proteins on biomedical materials such as vascular grafts is important in modulating thrombosis, one eventual cause of vascular graft failure. We have identified proteins expressed on the surfaces of retrieved vascular grafts to determine if certain proteins were present at the end stage of vascular failure. Scanning electron microscopic analysis of protein adsorption on the surfaces of retrieved vascular prostheses was determined using antibodies to human blood proteins fibrinogen, fibronectin, Hageman factor (factor XII) and factor VIII/von Willebrand Factor. The detection of these proteins on the blood contacting surface was evaluated by immunogold labelling with protein A-gold beads followed by silver enhancement. Fibronectin was the most abundant protein detected on retrieved expanded polytetrafluoroethylene or umbilical vein grafts. Protein adsorption was disperse for all proteins and one protein, fibronectin, was found in great amounts on all surfaces. Proteins such as fibronectin may be important in the adhesion and activation of platelets and leukocytes and thus contribute to the development of thrombosis. These analyses of human vascular grafts indicate that surface proteins can be readily detected by our methods and thus may be useful in determination of specific proteins important in the thrombogenicity and/or biocompatibility of cardiovascular devices