title: Hyaluronic acid decreases the mechanical stability, but increases the lytic resistance of fibrin matrices.
abstract: Hyaluronic acid (HA) is a large, non-sulfated glucosaminoglycan abundantly present at sites where fibrin is also formed (during wound healing, in arterial restenotic lesions and eroded atherosclerotic plaques). The aim of the present study was to characterize the structure of composite fibrin-HA clots with scanning electron microscopy (SEM), pressure-driven permeation and small-angle X-ray scattering (SAXS) and their viscoelastic properties with an oscillation rheometer. In addition the efficiency of fibrinolysis in these clots was investigated by kinetic turbidimetric and chromogenic assays for dissolution of fibrin and plasminogen activation by tissue-type plasminogen activator (tPA). Fibrin formed in the presence of native (1500kDa) HA and its 500kDa fragments had thicker fibers and larger pores according to the SEM and clot permeation data, whereas the 25kDa HA fragments had only minor effects. SAXS evidenced a mild disarrangement of protofibrils. These structural alterations suggest that HA modifies the pattern of fibrin polymerization favouring lateral association of protofibrils over formation of branching points. Rheometer data showed softer fibrin structures formed with 1500kDa and 500kDa HA and these clots presented with lower dynamic viscosity values and lower critical stress values at gel/fluid transition. tPA-catalysed plasminogen activation was markedly inhibited by HA, both in free solution and on the surface of fibrin clots, in the presence and in the absence of 6-aminohexanoate suggesting a kringle-independent mechanism. HA of 1500 and 500kDa size prolonged clot lysis with both plasmin and tPA and this inhibition was kringle-mediated, because it was abolished by 6-aminohexanoate and was not observed with des-(kringle1-4)-plasmin. Our data suggest that HA size-dependently modifies the pattern of fibrin polymerization with consequent inhibition of fibrinolysis. At sites of tissue injury and inflammation, HA could stabilize fibrin through modification of its structure and lysibility.
authors.affiliation: Department of Medical Biochemistry, Semmelweis University, 1094 Budapest, Tűzoltó utca 37-47, Hungary.
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Komorowicz
authors.affiliation: Department of Medical Biochemistry, Semmelweis University, 1094 Budapest, Tűzoltó utca 37-47, Hungary.
authors.forename: Nóra
authors.initials: N
authors.lastname: Balázs
authors.affiliation: Department of Biological Nanochemistry, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Magyar Tudósok körútja 2, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Varga
authors.affiliation: Department of Functional and Structural Materials, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Magyar Tudósok körútja 2, Hungary.
authors.forename: László
authors.initials: L
authors.lastname: Szabó
authors.affiliation: Department of Biological Nanochemistry, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Magyar Tudósok körútja 2, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Bóta
authors.affiliation: Department of Medical Biochemistry, Semmelweis University, 1094 Budapest, Tűzoltó utca 37-47, Hungary. Electronic address: Krasimir.Kolev@eok.sote.hu.
authors.forename: Krasimir
authors.initials: K
authors.lastname: Kolev
mesh_terms: D001777:Blood Coagulation; D005337:Fibrin / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D005342:Fibrinolysis; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D007700:Kinetics; D055503:Protein Multimerization; D055550:Protein Stability; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D005337:Fibrin; D006820:Hyaluronic Acid
keywords: Fibrin; Fibrinolysis; Hyaluronic acid; Plasmin; Plasminogen activation