Thromb Haemost 1985; 53(02): 228-234
DOI: 10.1055/s-0038-1661281
Original Article
Schattauer GmbH Stuttgart

A Role for Pericellular Proteoglycan in the Binding of Thrombin or Antithrombin III by the Blood Vessel Endothelium? – The Effects of Proteoglycan-Degrading Enzymes and Glycosaminoglycan-Binding Proteins on 125I-Thrombin Binding by the Rabbit Thoracic Aorta In Vitro

Mark W C Hatton
The Department of Pathology, McMaster University Health Sciences Centre, Hamilton, Ontario, Canada
,
Sue L Moar
The Department of Pathology, McMaster University Health Sciences Centre, Hamilton, Ontario, Canada
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Publikationsverlauf

Received 16. Oktober 1984

Accepted 15. Januar 1985

Publikationsdatum:
18. Juli 2018 (online)

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Summary

Rabbit thoracic aorta segments were treated with either proteoglycan-degrading enzymes or with glycosaminoglycan- binding proteins to examine the nature of the endothelial and subendothelial binding sites of 125I-thrombin. Treatment (5-30 min) with enzymes (heparitinase, chondroitinases AC or ABC) caused a decrease in 125I-thrombin binding by the endothelium (30-70%) and by the subendothelial (intima-media) layer (20-50%); a low- specificity protease destroyed endothelial binding almost entirely and reduced binding to the subendothelium by approximately 60% over a similar period. Of the glycosaminoglycan-binding proteins, pretreatment of the aorta wall with protamine caused a 30% decrease in thrombin binding to the endothelium whereas lipoprotein lipase (present during 125I-thrombin uptake) decreased binding by up to 40%. Pretreatment with antithrombin III did not significantly affect binding of either 125I-thrombin or 125I-FPR-inactivated thrombin. In contrast to thrombin, 125I- antithrombin III was not readily uptaken by the aorta segments. These observations indicate that, whereas the minimal binding by 125I-antithrombin III probably does not involve endothelial proteoglycan, a strong case can be made for endothelial and subendothelial proteoglycan binding sites for thrombin..