The role of coagulation factor XII in propagation of coagulation

• The physiological relevance and function of coagulation factor XII (FXII), the first zymogen in the intrinsic pathway, has for a long time been a matter of debate. The aim of this study was to shed some light on the role of factor XII in thrombus formation with a focus on its effect during the propagation phase of coagulation. In order to study propagation of coagulation we utilized a new imaging method to measure propagation rates from an activating surface in both platelet-free plasma and platelet-rich plasma. The most essential results revealed that both FXII and its substrate FXI are located on the surface of activated platelets. The surface of preexisting clots does not support coagulation in a FXII dependent manner. However, we found strong evidence for an accelerated propagation of tissue factor initiated coagulation when contact activation of FXII simultaneously occurred in the proximity. In vivo sources for contact activation may be exposed subendothelial collagen as well as soluble and cell derived poly-anions. If such in vivo contact activation of FXII occurs, even though moderate, it could contribute to in vivo thrombus growth rate and thus be of pathophysiological importance.

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MEDICINE

MEDICIN

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vet (ämneskategori)

ovr (ämneskategori)