Differential effects of staphylokinase, streptokinase and tissue-type plasminogen activator on the lysis of retracted human plasma clots and fibrinolytic plasma parameters in vitro.

A novel plasma clot lysis system was used to compare the fibrinolytic characteristics of staphylokinase, streptokinase and tissue-type plasminogen activator. 125I-fibrinogen-labelled human plasma clots were formed on needles and mechanically compressed after spontaneous retraction. This model is relatively resistant to lysis and differentiates between fibrin-specific and non-fibrin-specific plasminogen activators. The novel plasminogen activator, recombinant staphylokinase, produced high rates of clot lysis without markedly influencing fibrinogen, plasminogen and alpha 2-antiplasmin in the plasma containing the clots. At equimolar concentrations, streptokinase markedly depleted these parameters in plasma despite low clot lysis rates. Tissue-type plasminogen activator showed relatively high lysis rates at low concentrations, but at higher concentrations, plasminogen depletion caused a decrease in clot lysis. Staphylokinase can be characterised as a fibrin-specific and plasminogen-saving fibrinolytic agent with a high clot lysis potential.