Complex Formation of Fibrin Monomers Studied by Gel Filtration and Polyacrylamide Gel Electrophoresis

Abstract

Estimation and characterization of thrombin mediated products of fibrinogen (soluble fibrin monomer complexes=SFMC) can be achieved by gel filtration and PAA-gel electrophoresis. In order to gain further information about complex formation in vitro tests were performed. Fibrin monomers were prepared from fibrin dissolved in 3 M KBr after action of thrombin (des-AB-fibrin) and reptilase (des-A-fibrin) on fibrinogen and added to plasma. In a certain range of fibrin concentration (up to 3% for des-AB-fibrin and up to 15% for des-A-fibrin) soluble complexes are formed with fibrinogen in a 1:1 molar ratio. Further increase of fibrin percentage results in a partial precipitation of complexes. Additionally, a marked increase of SFMC (up to 60 %) is observed with des-A-fibrin. This latter reaction indicates complex formation with a higher ratio of fibrinogen involved. An influence of temperature on complex forming could be observed. Gel filtration at 37°C reveals a shift in the elu-tion profile, indicating dissociation of high molecular weight complexes (5 million daltons) to lower molecular structures. The dissociation behaviour of SFMC from plasma samples of patients with hypercoagulability is similar. However, crosslinked fibrinoligomers showed no temperature dependant dissociation behaviour. It is concluded that SFMC exist during the state of hypercoagulability in vivo predominantly as a dimeric fibrin-fibrinogen complex.