Fibrinolysis
Definition
The enzymatic breakdown of fibrin by plasmin, which is generated from plasminogen by tissue plasminogen activator (tPA). Menstrual blood has high tPA activity released by endometrial cells, preventing clot formation.
- Enzyme
- Plasmin acting on fibrin
- Activator
- Tissue plasminogen activator (tPA)
- Source in menstrual blood
- Endometrial cells release high tPA
- Effect
- Prevents clot formation
Common questions
Why does menstrual blood typically fail to clot while venous blood clots readily?+
Endometrial tissue releases unusually high levels of tPA, which drives plasmin generation fast enough to break down fibrin almost as it forms, so visible clotting is suppressed even though the coagulation cascade itself is intact.
How is fibrinolysis used to help distinguish menstrual blood from peripheral blood at a scene?+
Since menstrual blood resists clotting because of elevated tPA activity while shed peripheral blood clots normally, the presence or absence of clot formation and fibrin degradation products can support, though not by itself prove, a menstrual origin.
Related terms
- D-Dimer
- A fibrin degradation product generated when cross-linked fibrin is cleaved by plasmin. Elevated D-dimer in menstrual blood reflects the active fibrinolytic process;...
- Endometrial Shedding
- The physiological process by which the functional layer of the uterine endometrium is broken down and expelled during menstruation. The shedding process...
- Matrix Metalloprotease 10 (MMP-10)
- An endopeptidase of the MMP family involved in extracellular matrix remodelling during endometrial breakdown and shedding. Significantly elevated in menstrual blood and...
- mRNA Profiling
- Detection of messenger RNA transcripts specific to particular tissues or body fluids. Endometrial-specific transcripts (LEFTY2, MMP-10 mRNA, others) can distinguish menstrual blood...
- Tissue Plasminogen Activator (tPA)
- A serine protease secreted by endometrial cells and vascular endothelium that converts plasminogen to plasmin. Elevated in menstrual blood relative to peripheral...