Kinetic Studies of Soluble Fibrin Complexes in Vivo

Soluble fibrin complexes may occur in vivo in a variety of coagulation disorders. The aim of this investigation was to elucidate the in vivo behaviour of fibrin-fibrinogen complexes prepared in vitro in a ratio of 1 part fibrin to 20 parts fibrinogen. 12 rabbits (group A) were injected with soluble fibrin complexes containing homologeous I-131-fibrin and I-125-fibrinogen. Another group of 12 rabbits served as control (group B) and received I-131-fibrin solubilized in urea and I-125-fibrinogen separately from each other. Studies were performed over a period of 6 days. The mean distribution volume of fibrin as well as of fibrinogen did not significantly differ between both groups. The elimination characteristics of I-131-fibrin of the soluble fibrin complexes (group A) as well as of the solubilized fibrin (group B) were similiar. The fibrinogen elimination did not differ significantly between the groups: a mean T 1/2 of 47.8 h in group A and a T 1/2 of 46.7 h in group B was calculated. The experiments demonstrate that non-crosslinked soluble fibrin complexes distribute homogeneously in the circulation and dissociate into its subunits. Fibrin is eliminated from the circulating blood without influencing the normal catabolism of fibrinogen.