Thromb Haemost 1977; 37(01): 001-016
DOI: 10.1055/s-0038-1649196
Original Article
Schattauer GmbH

Platelet Interaction with Collagen Fibrils in Flowing Blood

I. Reaction of Human Platelets with α Chymotrypsin-Digested Subendothelium
Hans R. Baumgartner
1  Pharmaceutical Research Department, F. Hoffmann-La Roche and Co., Ltd., CH-4002 Basel, Switzerland
› Author Affiliations
Further Information

Publication History

Received 18 June 1976

Accepted 24 July 1976

Publication Date:
03 July 2018 (online)

Summary

The subendothelial surface of rabbit aorta and α chymotrypsin-digested subendothelium were exposed to anticoagulated human blood in an annular flow chamber. The wall shear rate was similar to that observed in large arteries (830 sec–1) and exposure times varied from 2½ to 40 min.

The platelet reactive substrate of α chymotrypsin-digested subendothelium consists of a three-dimensional meshwork of collagen fibrils which form islands of variable size and height in a matrix of virtually unreactive elastin. Collagen-induced aggregation in the aggregometer was similar with or without prior α chymotrypsin-digestion of a highly dispersed preparation of fibrillar collagen. The rate of platelet adhesion was decreased on the fibrillar collagen of α chymotrypsin-digested subendothelium as compared to intact subendothelium. On the other hand the rate of aggregation was increased once platelets adhered to the fibrillar collagen. Mural thrombi (aggregates) disappeared on subendothelium whereas they grew progressively on the fibrillar collagen. Thus the fibrillar collagen of α chymotrypsin-digested subendothelium appears to be a more thrombogenic surface. It is suggested that physical (loose three-dimensional meshwork versus a comparatively solid surface) and/or chemical (number of platelet reactive sites per unit surface area) differences between the two surfaces may explain the platelet-surface-interaction patterns which are characteristic for each surface.