Thromb Haemost 1993; 69(02): 141-146
DOI: 10.1055/s-0038-1651570
Original Article
Fibrinolysis
Schattauer GmbH Stuttgart

Assessment of the Relative Contribution of Different Protease Inhibitors to the Inhibition of Plasmin In Vivo

Marcel Levi
1   The Centre for Haemostasis, Thrombosis, Atherosclerosis and Inflammation Research, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
,
Dorina Roem
2   The Dept. of Autoimmune Diseases, Central Laboratory of the Netherlands Red Cross Bloodtransfusion Service and Laboratory for Clinical and Experimental Immunology, University of Amsterdam, Amsterdam, The Netherlands
,
Angela M Kamp
2   The Dept. of Autoimmune Diseases, Central Laboratory of the Netherlands Red Cross Bloodtransfusion Service and Laboratory for Clinical and Experimental Immunology, University of Amsterdam, Amsterdam, The Netherlands
,
Jan Paul de Boer
2   The Dept. of Autoimmune Diseases, Central Laboratory of the Netherlands Red Cross Bloodtransfusion Service and Laboratory for Clinical and Experimental Immunology, University of Amsterdam, Amsterdam, The Netherlands
,
C Erik Hack
2   The Dept. of Autoimmune Diseases, Central Laboratory of the Netherlands Red Cross Bloodtransfusion Service and Laboratory for Clinical and Experimental Immunology, University of Amsterdam, Amsterdam, The Netherlands
,
Jan Wouter ten Cate
1   The Centre for Haemostasis, Thrombosis, Atherosclerosis and Inflammation Research, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
› Author Affiliations
Further Information

Publication History

Received 06 August 1992

Accepted after revision 13 October 1992

Publication Date:
03 July 2018 (online)

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Summary

It has been shown that the most important inhibitor of plasmin is α2-antiplasmin, however, other protease inhibitors are able to inhibit this proteolytic enzyme as well. The contribution of the various protease inhibitors to the inhibition of plasmin in vivo has never been quantitatively assessed.

To assess the relative contribution of the different protease inhibitors on the inhibition of plasmin we developed a series of sensitive immunoassays for the detection of complexes between plasmin and the protease inhibitors α2-antiplasmin, α2-macroglobulin, antithrombin III, α1antitrypsin and C1-inhibitor, utilizing monoclonal antibodies that are specifically directed against complexed protease inhibitors and a monoclonal antibody against plasmin.

It was confirmed that α2-antiplasmin is the most important inhibitor of plasmin in vivo, however, complexes of plasmin with α2-macroglobulin, antithrombin III, α1antitrypsin- and C1-inhibitor were also detected. Particularly during activation of fibrinolysis complexes between plasmin and inhibitors other than α2-antiplasmin were detected. It was observed that during different situations the inhibition profile of plasmin was not constant e.g. in patients with diffuse intravascular coagulation plasma levels of plasmin-α1-antitrypsin and plasmin-C1-inhibitor were increased whereas in plasma from patients who were treated with thrombolytic agents complexes of plasmin with α2-macroglobulin and with antithrombin III were significantly elevated.

In conclusion, we confirmed the important role of α2-antiplasmin in the inhibition of plasmin, however, in situations in which fibrinolysis is activated other protease inhibitors also account for the inhibition of plasmin in vivo. Further investigations to assess the role of the various protease inhibitors in the fibrinolytic system can be assisted by the assays described in this study.