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Thromb Haemost 1990; 64(01): 047-052
DOI: 10.1055/s-0038-1647252
Original Article
Schattauer GmbH Stuttgart

Plasminogen Activation at Low Temperatures in Plasma Samples Gontaining Therapeutic Concentrations of Tissue-Type Plasm i nogen Activator or Other Thrombolytic Agents[*]

Authors

  • D C Rijken

    1   The Gaubius Institute TNO, Leiden, The Netherlands

  • E Seifried

    2   Medizinische Klinik und Poliklinik, Abteilung III, Universität Ulm, F.R.G.

  • M M Barrett-Bergshoeffi

    1   The Gaubius Institute TNO, Leiden, The Netherlands

  • G Dooijewaard

    1   The Gaubius Institute TNO, Leiden, The Netherlands
Weitere Informationen

Publikationsverlauf

Received 10. Oktober 1989

Accepted after revision 12. März 1990

Publikationsdatum:
25. Juli 2018 (online)

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Summary

It is known that in vitro plasminogen activation in blood samples taken during thrombolytic therapy with tissue-type plasminogen activator (t-PA) may lead to artefactually low fibrinogen and α2-antiplasmin values. To mimic this phenomenon, pooled normal plasma was supplemented with 2.5 μg/ml t-PA and incubated at various temperatures. The rates of fibrinogen degradation and α2-antiplasmin consumption were most pronounced at 37° C, were less pronounced at 25° C, but surprisingly, did not further decrease at 10° C, 0° C or −8° C. In contrast, when plasma was supplemented with 10° IU/ml urokinase or 30 IU/ml streptokinase, the rates of fibrinogen degradation and α2-antiplasmin consumption gradually decreased with incubation temperature and were negligible at 10° C and lower temperatures. The rate of plasminogen activation also decreased gradually with temperature in mixtures of purified fibrinogen, plasminogeo, α2- antiplasmin and t-PA. These results imply that, in a plasma milieu, additional factors with a stimulatory activity are involved in t-PA-induced plasminogen activation at around 0° C. The abnormally high reaction rate at low temperatures explains in vitro plasminogen activation observed during the processing of t-PA-containing blood samples.

In contrast to the activation of plasminogen by t-PA, the slow inhibition of t-PA (2.5 μg/ml) by proteinase inhibitors in plasma could be minimized to a negligible level by keeping the plasma samples at 0° C. This makes it possible to reliably monitor t-PA activity during thrombolytic therapy

Dedicated to Professor M. Verstraete on the occasion of his 65th birthday.