Contact activation of blood coagulation: trigger properties and hysteresis. Kinetic recognition of foreign surfaces upon contact activation of blood coagulation: a hypothesis.
A mathematical model of contact activation of blood coagulation was developed and analysed. The model variables are concentrations of factor XIIa, kallikrein and activated high-molecular-weight kininogen. Concentrations of active factors were shown to depend on the activating signal value in a hysteretic manner. Within a range of relatively small signals, two (activated and non-activated) stable states coexist (bistability). Signals of the natural environment (surfaces of endothelial and blood cells) seem to be in the range of bistability; therefore, contact activation that persists for a short time can induce a transition of the system to the activated state, and, correspondingly, the formation of a clot. The system cannot return to the initial state, which is characterized by low activation levels, until the activating signals decrease significantly below those present in the circulation.
Pokhilko
A V
AV
National Research Center for Hematology, Moscow, Russia.
Ataullakhanov
F I
FI
D001777:Blood Coagulation; D015956:Factor XIIa / Q000502:physiology; D018056:Hemorheology; D006801:Humans; D007610:Kallikreins / Q000502:physiology; D019679:Kininogen, High-Molecular-Weight / Q000502:physiology; D008433:Mathematics; D008954:Models, Biological
D019679:Kininogen, High-Molecular-Weight; D007610:Kallikreins; D015956:Factor XIIa