Related Experiment Video
Updated: May 19, 2026

Urokinase-type Plasminogen Activator-induced Mouse Back Pain Model
Published on: September 1, 2023
Plasma tissue-type plasminogen activator increases fibrinolytic activity of exogenous urokinase-type plasminogen
Boris Shenkman1, Tami Livnat, Ivan Budnik
1Laboratory of Hemostasis, Institute of Thrombosis & Hemostasis, and the National Hemophilia Center, Chaim Sheba Medical Center, Tel-Hashomer, Israel. borshenk@sheba.health.gov.il
Abstract:
The relationship between tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) function is not fully understood. The aim of this study was to compare in vitro the fibrinolytic activity of tPA and uPA and evaluate their possible interaction. Blood coagulation and fibrinolysis were conducted by rotation thromboelastometry, whereas blood clotting was induced by CaCl2 and tissue factor and fibrinolysis additively by tPA and uPA. Effective concentration 50% of tPA and uPA fibrinolytic activity in blood was found to be 90 and 33 IU/ml relating to the units of activity established by manufacturers in the absence of blood. uPA-induced fibrinolysis in blood was faster compared with tPA used at the same units of activity. In contrast, in a blood-free system containing fibrinogen, plasminogen, and thrombin, fibrinolysis induced by uPA was weaker than by tPA. Treating of blood with tranexamic acid (60 mmol/l) was followed by decreased fibrinolytic potential of both exogenous tPA and uPA, despite uPA by itself is known to be not sensitive to aminocaproic acids. Thus, uPA exerted stronger activity in blood but weaker activity in blood-free system, compared with tPA. Taking into account the intermolecular binding of uPA to tPA, it could be suggested that interaction of exogenous uPA with plasma-containing tPA provided amplification of fibrinolysis due to formation of uPA/tPA complex possessing high affinity to fibrin.
Related Concept Videos
Clot Retraction and Fibrinolysis
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which forms a...
Venous Thrombosis III: Interprofessional Care
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
Introduction to Hemostasis
The three phases of hemostasis involve many clotting factors present in plasma and several substances released by platelets and injured tissue cells. It is a fast, localized, and...

