Considering Multiple Modes of Blood Coagulation

Abstract

For the life of every creature is its blood: Its blood is its life.

Genesis 9:4.

Blood coagulation is a critical process for all blooded creatures… a process that arrests critical blood loss due to injury.  The classical view of blood coagulation is based on a cascade mechanism whereby a sequence of enzymatic clotting factors (factors XIII, XII, IX, X, IX, VIII, VII, V) generate thrombin (II), which ultimately enzymatically  converts  soluble fibrinogen  (I) into an insoluble  fibrin clot.

More recently, an alternate clotting mechanism has been described based on free-radical induced transformation of fibrinogen into an insoluble matrix (sic. clot). The OH^. free radicals could be generated by a Fenton-type reaction, as between ascorbate (Vit C) and Cu⁺². Alternately, they could be generated by UVC or g-irradiation interacting with protein.

Here, we review both mechanistic options and discuss some clinical implications for earth-bound thrombotic patients and for astronauts living in outer space.