Direct observation of platelet adhesion to fibrinogen- and fibrin-coated surfaces

A flow system consisting of a parallel-plate flow chamber mounted on the epifluorescence video microscope was constructed to allow direct visualization of the entire platelet adhesion process under flow conditions. Digital image-processing techniques were applied to analyze the fluorescence images from video tapes. In this study we used cover glasses coated with either fibrinogen or fibrin as the testing surface of our flow chamber to compare platelet adhesion to both types of surfaces. We found that 1) platelets adhered to both types of protein-coated surfaces but not to uncoated glass; 2) platelets that adhered to fibrinogen were nonoverlapping, clustering, and saturated at approximately 40 cells/1,000 microns 2 at 445 s-1 surface shear rate and at approximately 60 cells/1,000 microns 2 at 70 s-1 surface shear rate; 3) platelets that adhered to fibrin were nonoverlapping, random, and saturated at approximately 55 cells/1,000 microns 2 at 445 s-1 surface shear rate and at approximately 65 cells/1,000 microns 2 at 70 s-1 surface shear rate; 4) ethyleneglycol- bis(beta-aminoethylether)-N,N'-tetraacetic acid, the snake venom halysin (against glycoprotein IIb-IIIa complex), and monoclonal antibody Ab-15 (against glycoprotein IIIa) blocked platelet adhesion to both surfaces; 5) Arg-Gly-Asp-Ser and monoclonal antibody LIBS-1 (against glycoprotein IIIa) partially inhibited platelet adhesion to fibrinogen-coated surface but were almost ineffective in preventing platelet adhesion to fibrin-coated surface; and 6) monoclonal antibody Ab-144 (against glycoprotein Ib) was ineffective for platelet adhesion on both surfaces. These observations provide basic characteristics of platelet adhesion to fibrinogen- and fibrin-coated surfaces under controlled flow conditions.(ABSTRACT TRUNCATED AT 250 WORDS)