title: Effects of cross-linking on clearance of circulating alpha-fibrin monomer and its complexes.
abstract: Preceding studies showed that fibrin-monomer of the type lacking only fibrinopeptide A (alpha-fibrin) cleared from the circulation more rapidly than a tighter aggregating form of monomer that lacks both fibrinopeptides A and B (alpha beta-fibrin). The rapid clearance of alpha-fibrin may be related to the high dissociability of the soluble complexes that it forms with fibrinogen in blood. In this study, we use cross-linking by factor XIIIa to suppress dissociation of fibrin complexes and examine the effect of the cross-linking on the circulatory half-life of the fibrin. Incubation of alpha-fibrin-monomer/fibrinogen solutions with factor XIIIa before injection in rabbits increased the circulatory half-life of the fibrin (range, 2 to 16 hours) in proportion to the percentage conversion of monomer to cross-linked dimers and small oligomers. Electrophoretic analyses of plasma samples confirmed that, compared with non-cross-linked monomer, cross-linked dimers and small oligomers were long lived and, further, were not degraded. The inhibition of clearance through cross-linking occurs only under conditions that produce partial cross-linking of the fibrin. An opposite effect occurs when cross-linking is allowed to approach completion, as a result of polymerization of the fibrin into large fibers that disappear almost immediately after injection. Cross-linking elicited in vivo with injected factor XIIIa has an inhibitory effect on clearance of injected monomer similar to the effect produced by partial cross-linking in vitro. It is proposed that the prolonged survival of cross-linked dimers and small oligomers in the circulation provides a partial explanation for the frequent prevalence of cross-linked rather than non-cross-linked complexes in blood of human subjects with vascular disease.
authors.affiliation: Research Institute, Cleveland Clinic Foundation, OH 44195.
authors.forename: J R
authors.initials: JR
authors.lastname: Shainoff
authors.forename: B N
authors.initials: BN
authors.lastname: Dardik
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D004587:Electrophoresis, Agar Gel; D005337:Fibrin / Q000378:metabolism / Q000493:pharmacokinetics*; D005340:Fibrinogen / Q000493:pharmacokinetics*; D005344:Fibrinopeptide A / Q000493:pharmacokinetics*; D006207:Half-Life; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D008970:Molecular Weight; D011817:Rabbits; D011503:Transglutaminases / Q000494:pharmacology*
chemical_list: D005344:Fibrinopeptide A; D005337:Fibrin; D005340:Fibrinogen; D011503:Transglutaminases