Early reactions between whole blood and hydrophilic or hydrophobic glass surfaces: effects of heparin and hirudin on von Willebrand factor binding and CD62P exposure on platelets

Abstract

Early reactions between human whole blood and cleaned hydrophilic or methyl-silanized hydrophobic glass surfaces were investigated. The blood was either anticoagulated or not with heparin or hirudin. The von Willebrand factor (vWF) and the platelet coverage as well as CD62P exposure, were localized by immunofluorescence and quantitated by computer aided image analysis. The surface coverage and the number of adhering platelets were used to measure cell spreading. Platelets adhered to the surfaces within 5 s of blood material contact. With untreated blood, vWF was seen bound at the cell surfaces after 2 min of blood material contact at the hydrophilic surfaces. P-selectin (CD62P) was exposed on the platelet cell surface after 8 min of blood–material contact at the hydrophilic surfaces. At the hydrophobic surfaces, less vWF and CD62P exposure were seen. Anticoagulation with both hirudin and heparin abolished the binding of vWF and the exposure of CD62P during the 8 min studied, indicating that these events are thrombin-dependent. Heparin, but not hirudin, also inhibited spreading of the platelets.