Interaction of platelets and purified collagens in a laminar flow model

Damage to the endothelial surface of the vessel wall can result in exposure of circulating blood components to collagen and other subendothelial structures. Collagen types I, III, IV, and V have been demonstrated in the vessel wall by chemical and immunohistological methods; type V is thrombin-sensitive, and is present on the endothelial cell surface. In an earlier study using a rocking model, both unstimulated and ADP-induced platelet adherence was reduced on wells coated with type V collagen in comparison to uncoated wells; and increased on plastic surfaces coated with types III and IV collagen in comparison to those coated with type V collagen. The present study was designed to determine the effect of erythrocytes and shear rate on platelet adherence to these purified collagen types in a laminar flow system. With platelet-rich plasma, adherence of labeled platelets was much lower in the laminar flow system compared with the rocking model. Erythrocytes significantly enhanced platelet adherence to surfaces that were untreated or absorbed with collagen types I, III, and IV. However, this enhancement was not seen in the presence of type V collagen. These studies provide additional evidence for the selectively nonthrombogenic nature of type V collagen.