Procoagulant activity of collagen. Effect of difference in type and structure of collagen

Procoagulant activities of different types and structures of collagen were examined. Collagens used were types I (including its methylated and succinylated forms), II, III, IV and V. Each collagen was coated on an inner surface of a glass tube. The change of fluidity during coagulation of blood in the tube was measured by means of a new rheological technique. For monomeric collagen, the procoagulant activity of the succinylated form (negatively charged) was higher than that of the methylated form (positively charged). The procoagulant activity of type IV (dry) was lower than that of other types of collagen. For fibrillar collagens, the initiation of coagulation for type V (non-banded) was fairly delayed compared to those for types I, II and III (banded). An increase in water content in both monomeric and fibrillar forms promoted procoagulant activity. For most of the collagen forms, the addition of factor XII inhibitor (Polybrene) to blood brought about a remarkable delay of the initiation of coagulation, suggesting that the activation of factor XII on the collagen surface is one of main factors governing procoagulant activity. In addition, our data suggest that large numbers of adherent platelets to the collagen surface promote activation of the intrinsic coagulation system.