Thrombin Activity Propagates in Space During Blood Coagulation as an Excitation Wave

Abstract

Injury-induced bleeding is stopped by a hemostatic plug formation that is controlled by a complex nonlinear and spatially heterogeneous biochemical network of proteolytic enzymes called blood coagulation. We studied spatial dynamics of thrombin, the central enzyme of this network, by developing a fluorogenic substrate-based method for time- and space-resolved imaging of thrombin enzymatic activity. Clotting stimulation by immobilized tissue factor induced localized thrombin activity impulse that propagated in space and possessed all characteristic traits of a traveling excitation wave: constant spatial velocity, constant amplitude, and insensitivity to the initial stimulation once it exceeded activation threshold. The parameters of this traveling wave were controlled by the availability of phospholipids or platelets, and the wave did not form in plasmas from hemophilia A or C patients who lack factors VIII and XI, which are mediators of the two principal positive feedbacks of coagulation. Stimulation of the negative feedback of the protein C pathway with thrombomodulin produced nonstationary patterns of wave formation followed by deceleration and annihilation. This indicates that blood can function as an excitable medium that conducts traveling waves of coagulation.

Preserved clot formation detected by the Thrombodynamics analyzer in patients with cirrhosis

“…The general concept of the Thrombodynamics test was previously described by others [9,10,15,16]. Briefly, in a thin layer of plasma coagulation is activated when it is brought in contact with tissue factor (TF) immobilized on a plastic surface.…”

Factor XI and traveling waves: the key to understanding coagulation in hemophilia?

“…Recently, we were able to directly measure thrombin distribution in the growing clot in vitro [16]. High concentration of thrombin is produced near the activating TF-coated surface.…”

“…In the absence of FXI, the moving thrombin peak is not formed and the local concentration of thrombin far from the activator at the time of clot formation is much lower [16]. This can lead to an increased fibrinolysis rate for the reasons mentioned above.…”

More efficient reversal of dabigatran inhibition of coagulation by activated prothrombin complex concentrate or recombinant factor VIIa than by four-factor prothrombin complex concentrate

“…This method has been described in several articles [12][13][14]. Coagulation was detected in a cuvette by time-lapse image capture of light scattering from the fibrin network.…”