Thromb Haemost 1996; 75(01): 127-133
DOI: 10.1055/s-0038-1650232
Original Article
Schattauer GmbH Stuttgart

Proteins of the Fibrinolytic System in Human Thrombi

Linda A Robbie
1   The Department of Medicine and Therapeutics, University of Aberdeen, Aberdeen, Scotland, UK
2   The Department of Molecular and Cell Biology, University of Aberdeen, Marischal College, Aberdeen, Scotland, UK
,
Bruce Bennett
1   The Department of Medicine and Therapeutics, University of Aberdeen, Aberdeen, Scotland, UK
,
Alison M Croll
1   The Department of Medicine and Therapeutics, University of Aberdeen, Aberdeen, Scotland, UK
,
Paul A J Brown
3   The Department of Pathology, University of Aberdeen, Aberdeen, Scotland, UK
,
Nuala A Booth
2   The Department of Molecular and Cell Biology, University of Aberdeen, Marischal College, Aberdeen, Scotland, UK
› Author Affiliations
Further Information

Publication History

Received 10 May 1995

Accepted after resubmission 04 October 1995

Publication Date:
10 July 2018 (online)

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Summary

The proteins of fibrinolysis have been quantified in human thrombi, to assess the balance between plasminogen activators and their major inhibitor PAI-1. The relative roles of PAI-1 and α2-AP were also examined since we have previously shown that both platelet PAI-1 and plasma α2-AP are important determinants of clot lysis in vitro. Extracts and sections were prepared from human thrombi for quantitative immunoassay and immunohistochemical staining respectively. PAI-1 and α2-AP were present at high concentrations. Levels of t-PA and t-PA-PAI-1 complex were relatively low. Staining confirmed the presence of abundant PAI-1, associated primarily with platelet material within the thrombus and also with fibrin. Staining for α2-AP was also intense and demonstrated strong association with fibrin. The α2-AP concentration was similar to its high plasma concentration, whereas PAI-1 levels were up to 30 times greater than that in circulating blood, suggesting that active recruitment of platelets contributes to the high PAI-1 concentration in thrombi.