Distribution of alpha-polymers and residual alpha-chains in in vitro and in vivo formed fibrin clots.

In vitro and in vivo formed fibrin clots were investigated by SDS-PAA gel electrophoresis in regard to the amount and distribution of fibrin subunits. It was found that with decreasing factor XIII levels fewer and shorter alpha-polymers were formed in vitro and more so in the exterior than in the core of a clot. Inversely the concentrations of residual alpha-chains rose. These structural changes already began at factor XIII levels of 50%. gamma-dimer formation was not influenced. Nearly all in vivo thrombi, either arterial or venous, consisted of a normal distribution of subunits, but alpha-polymerization was more extensive in the core than in the exterior parts. A significant impairment of alpha polymerization was found in extravasal clots, but not in thrombi formed during anticoagulant therapy.