Human plasma fibronectin promotes the adhesion and spreading of platelets on surfaces coated with fibrillar collagen.

This letter reports that human plasma fibronectin stimulates the interaction of platelets with fibrillar collagen (cell adhesion) and also dramatically changes the shape of adherent platelets, promoting their spreading. The stimulating effect of fibronectin is due to its interaction with collagen fibrils since free fibronectin does not influence the adhesion or spreading of platelets. The results obtained suggest a new physiological function for plasma fibronectin in the control of platelets interaction with damaged vessel walls.