title: Fibronectin alters the rate of formation and structure of the fibrin matrix.
abstract: Plasma fibronectin is a vital component of the fibrin clot; however its role on clot structure is not clearly understood. The goal of this study was to examine the influence of fibronectin on the kinetics of formation, structural characteristics and composition of reconstituted fibrin clots or fibrin matrices. Fibrin matrices were formed by adding thrombin to 1, 2 or 4 mg/ml fibrinogen supplemented with 0-0.4 mg/ml fibronectin. The rate of fibrin matrix formation was then monitored by measuring light absorbance properties at different time points. Confocal microscopy of fluorescein conjugated fibrinogen was used to visualize the structural characteristics of fibrin matrices. The amount of fibronectin in fibrin matrices was determined through electrophoresis and immunoblotting of solubilized matrices. Fibronectin concentration positively correlated with the initial rate of fibrin matrix formation and with steady state light absorbance values of fibrin matrices. An increase in fibronectin concentration resulted in thinner and denser fibers in the fibrin matrices. Electrophoresis and immunoblotting showed that fibronectin was covalently and non-covalently bound to fibrin matrices and in the form of high molecular weight multimers. The formation of fibronectin multimers was attributed to cross-linking of fibronectin by trace amounts Factor XIIIa. These findings are novel because they link results from light absorbance studies to microcopy analyses and demonstrate an influence of fibronectin on fibrin matrix structural characteristics. This data is important in developing therapies that destabilize fibrin clots.
authors.affiliation: Department of Chemical and Biological Engineering, Illinois Institute of Technology, 10 West 33rd, Chicago, IL 60616, United States.
authors.forename: Anand
authors.initials: A
authors.lastname: Ramanathan
authors.affiliation: Department of Chemical and Biological Engineering, Illinois Institute of Technology, 10 West 33rd, Chicago, IL 60616, United States. Electronic address: nkaruri1@iit.edu.
authors.forename: Nancy
authors.initials: N
authors.lastname: Karuri
mesh_terms: D001665:Binding Sites; D019281:Dimerization; D005337:Fibrin / Q000737:chemistry* / Q000648:ultrastructure*; D005353:Fibronectins / Q000737:chemistry* / Q000648:ultrastructure*; D007700:Kinetics; D011485:Protein Binding
chemical_list: D005353:Fibronectins; D005337:Fibrin
keywords: Extracellular matrix; Fibrin; Fibrin matrix; Fibronectin; Kinetics; Structure