Fibrin Monomer Polymerization Research Articles

Fibrinogen Vicenza and Genova II: Two New Cases of Congenital Dysfibrinogenemia with Isolated Defect of Fibrin Monomer Polymerization and Inhibitory Activity on Normal Coagulation

Two new cases of congenital dysfibrinogenemia are presented in which defective fibrin monomer polymerization and inhibitory activity on normal coagulation were observed. They have been tentatively called fibrinogen Vicenza and Genova II. The first was discovered in a family with mild bleeding diathesis, the second in an asymptomatic family. In almost all reported cases of fibrinogens with defective fibrin monomer polymerization, additional functional or structural defects have been detected. In our cases, on the contrary, detailed investigations failed to show any other abnormality. Fibrinogen Genova II is apparently identical to fibrinogen Baltimore IV, whereas fibrinogen Vicenza is similar to fibrinogen Troyes and Genova I, but also exerts an evident inhibitory activity on normal coagulation and differs from fibrinogen Genova II and Baltimore IV showing a different kinetic pattern of fibrin monomer polymerization.

フィブリン構造と系の濁度に関する研究 （ＩＩ）

In the fibrinogen-fibrin conversion, remarkable turbidity changes can be observed in experimental conditions of both a neutral pH and low ionic strength. The relationships between fibrin structure and turbidity changes were studied. In the region, which slope is designated as αI, of the initial small turbidity changes on the turbidity-time curve obtained experimentally, the hydrolysis of fibrinogen by thrombin was stopped by adding a potent thrombin inhibitor MD-805. Then dimer and trimer of fibrin monomers, detected from the reaction mixture by a SDS (0.1%)-agarose (2%) gel electrophoresis, were regarded as nuclei of polymerization of fibrin monomers.On the other hand, the region, which slope is designated as αII, of the most remarkable turbidity change, e. g., αII/αI=10, on the turbidity-time curve could be attained neither by increase of the equilibrium constants in the simplified model for the polymerization of fibrin monomer nor by the formation of infinitely long fibrin polymer. Thus, the remarkable turbidity changes in the fibrinogen-fibrin conversion was deduced not only by the contribution of the growth of protofibrils but also by the lateral association of protofibrils.

Human factor XIa cleaves fibrinogen: Effects on structure and function

Factor XIa, the enzymatic form of the factor XI zymogen, is generated as a result of factor XII-dependent surface activation in plasma. Factor XIa degrades high molecular weight kininogen, its cofactor for activation (which binds factor XIa to the surface), as well as cleaves and activates coagulation factor IX. In this report, we present evidence that factor XIa can also cleave fibrinogen and decrease the thrombin-catalyzed formation of the fibrin clot. Furthermore, the products of factor XIa-digested fibrinogen markedly inhibited the rate of polymerization of fibrin monomers. Factor XIa initially cleaved the Aα-chain of fibrinogen and subsequently degraded the Bβ-chain. However, the cleavage sites on both chains were distinct from those susceptible to thrombin. The γ-chain was degraded only after prolonged incubation with factor XIa. Furthermore, the profile of fibrinogen proteolysis by factor XIa was distinctly different from that of plasmin-catalyzed fibrinogenolysis. Unlike plasmin, factor XIa was not able to cleave the NH 2-terminus of the Bβ-chain of fibrinogen. Moreover, factor XIa, unlike plasmin, failed to hydrolyze fibrin. Further study of the proteolytic digests of fibrinogen produced by factor XIa may give additional insight into the mechanism of polymerization of this protein.

Expression of primary polymerization sites in the D domain of human fibrinogen depends on intact conformation.

Fragments D1 and DD, plasmic degradation products of human fibrinogen and cross-linked fibrin, respectively, originate from the COOH-terminal domain of the parent molecule. Since a specific binding site for fibrin resides in the COOH-terminal region of the gamma chain, the primary structure of the two fragments was compared and their affinity for fibrin monomer measured. Fragments D1 and DD contained the same segments of the three fibrinogen chains, corresponding to the sequences alpha 105-206, beta 134-461, and gamma 63-411. Fragment DD had a double set of the same chain remnants. Fragments D1 and DD inhibited polymerization of fibrin monomer in a dose-dependent manner; 50% inhibition occurred at a molar ratio of fragment to monomer of 1:1 and 0.5:1, respectively. To prevent fibrin monomer polymerization and render it suitable for binding studies in the liquid phase, fibrinogen was decorated with Fab fragments isolated from rabbit antibodies to human fragment D1. Fibrinogen molecules decorated with 6 molecules of this Fab fragment did not clot after incubation with thrombin, and the decorated fibrin monomer could be used to measure binding of fragments D1 and DD in a homogeneous liquid phase. The data analyzed according to the Scatchard equation and a double-reciprocal plot gave a dissociation constant of 12 nM for fragment D1 and 38 nM for fragment DD. There were two binding sites/fibrin monomer molecule for each fragment. After denaturation in 5 M guanidine HCl, the inhibitory function on fibrin polymerization was irreversibly destroyed. Denatured fragments also lost binding affinity for immobilized fibrin monomer. The preservation of the native tertiary structure in both fragments was essential for the expression of polymerization sites in the structural D domain.

The anticoagulant properties of mast cell product, chondroitin sulphate E

The anticoagulant potency in vitro of chondroitin sulphate E has been found to be similar to that of the heparinoids. In purified systems chondroitin sulphate E was shown to be principally an activator of heparin cofactor II. Maximum acceleration of heparin cofactor II:thrombin interaction was 185-fold (9.3×10 7 M −1 min −1), antithrombin III:thrombin interaction was 11-fold (4.16×10 6 M −1 min −1) and antithrombin III:factor Xa was 146-fold (3.86×10 6 M −1 min −1). Chondroitin sulphate E was observed to prolong the thrombin clotting time of fibrinogen in the absence of antithrombin III and heparin cofactor II. The effect appeared to be related to interference in thrombin:fibrinogen interaction rather than in fibrin monomer polymerization.

Multiple Myeloma With Polyneuropathy and Coagulopathy

• A patient with the syndrome of polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) had multiple myeloma and IgA-κ monoclonal gammopathy. To our knowledge, of over 50 cases in the literature, this is the only instance of κ light chains noted in a patient with the complete syndrome. Sural nerve biopsy revealed increased immunofluorescence for IgA and κ chains. Furthermore, this patient had a hemorrhagic diathesis characterized by a prolonged bleeding time and a prolonged thrombin time due to a qualitative platelet dysfunction and an apparent inhibition of fibrin monomer polymerization. In none of the other cases of POEMS syndrome was a coagulopathy reported. A short course of plasmapheresis improved the bleeding time but did not alter the polyneuropathy. (Arch Intern Med1986;146:993-994)

Localization of segments essential for polymerization and for calcium binding in the gamma-chain of human fibrinogen.

We have isolated an intermediate plasmic degradation product, D2, of fibrinogen that does not inhibit the polymerization of fibrin monomer but does bind Ca2+. Fibrinogen was digested to a limited extent with plasmin in the presence of Ca2+, and a "large" fragment D (fragment D1A) was isolated with a gamma-chain remnant consisting of residues 63-411. Fragment D1A was digested further in the presence of Ca2+, yielding fragment D1 (with its gamma-chain containing residues 86-411). The digestion of fragment D1 [in the presence of ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) to complex Ca2+] led to a gradual shortening of the carboxyl-terminal portion of the gamma-chain. Fragment D2 (with its gamma-chain containing residues 86-335/356) was isolated from an intermediate digest in the presence of EGTA. The Lys-338-Cys-339 peptide bond of the gamma-chain is intact in this preparation of D2, even though it is split in the isolated peptide gamma303-355 (with an intact disulfide bond at Cys-326-Cys-339). Fragment D2 does not interfere with the polymerization of fibrin monomer, whereas fragment D1 is a potent inhibitor of this polymerization. We conclude that the gamma-chain segment 356/357-411, present in fragment D1 but absent from fragment D2, is essential for maintenance of a polymerization site located in the outer (D) nodule of fibrinogen. This segment (356/357-411) is longer than two shorter ones reported earlier [Olexa, S.A., & Budzynski, A. Z. (1981) J. Biol. Chem. 256, 3544-3549; Horwitz, B.H., Váradi, A., & Scheraga, H.A. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 5980-5984]; the data for the earlier reports are reinterpreted here. Finally, fragment D2 possesses a single Ca2+ binding site, as revealed by equilibrium dialysis binding studies. Since fragment D3 (with its gamma-chain containing residues 86-302) fails to bind Ca2+, we conclude that segment gamma 303-355/356 plays a crucial role in Ca2+ binding.

Reduced aggregation capacity of washed platelets and dysfibrinogenaemia in rats given butylated hydroxytoluene

Calcium-dependent aggregation of washed platelets and the fibrin monomer polymerization (FMP) ratio were determined in rats fed 1.20% butylated hydroxytoluene (BHT) for 7 days. Thrombin-induced aggregation was significantly reduced in rats given BHT, but calcium ionophore A23187-induced aggregation was not. The FMP ratio was significantly increased by BHT administration. These results provide additional evidence of defective platelet function and coagulation-factor abnormality (dysfibrinogenaemia) in rats fed BHT.

Fibrinogen baltimore IV: Congenital dysfibrinogenemia with delayed fibrin monomer polymerization

A congenital dysfibrinogenemia, fibrinogen Baltimore IV, has been found in a 56-year-old Caucasian man. Clinical laboratory studies disclosed a slightly prolonged prothrombin time, but were otherwise unremarkable. Release of fibrinopeptldes by thrombin occurs normally, as does ligation of the fibrin polymer by Factor XIII. Approximately half of the isolated fibrin monomers polymerize normally, but the remainder polymerize at about 2% of the initial rate. The functional defect is thus limited to a decrease in the rate of fibrin monomer polymerization.

In vitro study of the inhibition of coagulation induced by different radiocontrast molecules

The anticoagulant activity of seven intravascular radiocontrast molecules (RCM) was evaluated in different in vitro systems using citrated human plasma. Each RCM was tested in a concentration range of 5 to 50 mM. The thrombin time and the reptilase time showed a dose-dependent lengthening of fibrinoformation, the recording of fibrinoformation exhibited a significant delay of fibrin monomer generation and polymerization although the amplitude of the fibrino-formation was not decreased. The interfering effect with fibrin clot formation impairs also global coagulation tests and monospecific coagulation tests using fibrinoformation as the final step of the assay, but a possible interaction between RCM and some specific coagulation factors cannot be excluded. RCM potentiated the anti-thrombin action of heparin but the inhibition or delay of fibrino-formation is not related to an antithrombinic effect of contrast media. The thrombin amidolytic activity is not modified by RCM but the generation of FpA is delayed and decreased. The ultrastructure of the fibrin clot is not altered at the end of the polymerization.

Fibrinogen seattle II: Defective release of fibrinopeptide a in a slow clotting fibrinogen

A functionally abnormal fibrinogen was detected in a 27-year-old woman with no prior history of bleeding. Investigation of the defect revealed abnormal release of fibrinopeptide A and incomplete polymerization of fibrin monomers. Crosslinking of polymerized fibrin by Factor XIII was normal. To further characterize the dysfibrinogen, the increase in mechanical impedance during clot development was measured. Fibrinogen Seattle II showed several differences from normal fibrinogen: delayed onset of clotting, decreased rate of clot formation, and lower final clot impedance. Taken cumulatively, these data are consistent with an amino acid substitution at or near residue 16 in one of the Aα chains, the point at which thrombin cleaves.

Inhibition of some activities of thrombin by a collagen-derived octapeptide.

The effect of a collagen-derived octapeptide on some properties of thrombin is presented. This peptide provoked a dose- and time-dependent prolongation of the thrombin-induced plasma and fibrinogen clotting time and inhibited the polymerization of fibrin generated from fibrinogen by thrombin. It did not affect the polymerization of fibrin monomers; it was also without effect on the coagulation of plasma or fibrinogen by reptilase. The prolongation of the fibrinogen clotting time depended on the duration of the incubation of thrombin and the octapeptide and not on the duration of the incubation of fibrinogen and the octapeptide. The inhibition was therefore ascribed to an interference with thrombin, rather than with fibrinogen. A preincubation of the octapeptide with thrombin resulted in an inhibition of the thrombin-induced platelet aggregation. The effect of the octapeptide on thrombin has been related to the presence of positively and negatively charged groups, because uncharged analogue sequences were without effect on these activities of thrombin.

Inhibition or acceleration of fibrin polymerization by monoclonal immunoglobulins and immunoglobulin fragments

A prolongation of the thrombin clotting time by at least 25% was found in the presence of 8 of 26 IgG myeloma proteins, 2 of 5 IgA proteins and 1 of 10 macroglobulins, in a concentration of 10 mg/ml. Normal pooled immunoglobulin in concentrations up to 83 mg/ml were inactive. 2 IgG and 2 IgM monoclonal immunoglobulins caused an acceleration of the thrombin time by at least 20%; this phenomenon has not been reported before. Corresponding results were obtained with these proteins when the polymerization of des-AA and des-AABB fibrin monomers were investigated in a light scattering system. Studies with enzymatically produced Fab, F(ab′)2 and Fc fragments from normal and monoclonal immunoglobulin suggested that the polymerization inhibitory activity resides in the Fab portion of the immunoglobulin molecule. While the ability to inhibit fibrin polymerization may be an immunoglobulin specific effect, the acceleration caused by certain other monoclonal immunoglobulins may be an unspecific effect similar to that seen with dextran or albumin.

Stability of plasma fibrinogen during storage of platelet concentrates at 22 degrees C.

Platelet concentrates (PC) are stored for up to 5 days at 22 degrees C prior to infusion. Since considerable suspending plasma is infused with the platelets, we examined the integrity of plasma fibrinogen from stored PC. The concentration of fibrinogen after storage was normal. After purification, fibrinogen from stored PC had normal thrombin time and rate of polymerization of fibrin monomer, and after reduction, its A alpha, B beta, and gamma chains had normal mobility on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Assays of plasma from stored PC for fibrinogen-fibrin degradation products were negative. When 125I-fibrinogen was added to PC prior to storage and supernatant plasma was filtered in a sepharose 4B column after storage, radioactivity eluted in a single, symmetrical peak with no evidence for formation of low or high molecular weight material. These results make it unlikely that thrombin, plasmin, or other proteolytic activity is generated during storage. The levels of factors V and VIII fell to 40 to 65 percent of control values while the activities of factors IX, X, and XI did not change significantly during storage. We conclude that suspending plasma fibrinogen and other coagulation factors are remarkably stable during PC storage. They should be of value during the support of patients with massive hemorrhage.

Anticoagulant and antiheparin activities of a pentosan polysulphate

Pentosan polysulphate (PPS, Hemoclar, MW 6,700) was observed to have a low affinity for ATIII-Sepharose eluting at 0.3M NaCl. Tested in vitro it had, as previously reported, a low potency as an anticoagulant, about 10 times less than heparin on a weight for weight basis. Only the KCCT was affected by low concentrations of PPS unlike heparin by which both affected. Upon injection of PPS subcutaneously (50mg) the heparin activity measured by chromogenic the ratio of 2:1. When injected intravenously (40mg) into 3 healthy volunteers a significant prolongation of a modified prothrombin time was observed in 2 subjects. When PPS was added to heparin containing plasma it was observed to completely inhibit heparin at low concentrations (2:1 on a weight to weight basis) when measured in the thrombin and prothrombin time but not in the KCCT. The antiheparin effect of PPS was also observed in a purified system in obviating the heparin potentiation of the rate of inhibition of thrombin by antithrombin III. Observations showed that at higher concentrations of PPS it acted by directly inhibiting thrombin without the intervention of antithrombin III but also to potentiate the rate of fibrin monomer polymerization.

A new type of congenital dysfibrinogenaemia with defective fibrin lysis--Dusard syndrome: possible relation to thrombosis.

Congenital dysfibrinogenaemia is described in three members of a family presenting with recurrent thrombosis and in two other young members not yet affected. An abnormality in the polymerization of fibrin monomers was noted. In addition, the pathological fibrin clots were found to be less sensitive to degradation by a post venous occlusion euglobulin solution than normal fibrin. After fibrin clot incubation with lys-plasminogen at different concentrations, the biological activity of plasminogen in patient fibrin clot on S 2251 after SK-addition, was less than that observed with normal fibrin. It is speculated that defective in vivo thrombolysis might explain the recurrent thrombosis observed in this family. This finding represents a new concept in understanding thromboembolic diseases.

Delayed release of an abnormal fibrinopeptide A from fibrinogen Manchester: effect of the A alpha 16 Arg leads to His substitution upon fibrin monomer polymerization and the immunological crossreactivity of the peptide.

Fibrinogen Manchester is an abnormal fibrinogen with an impaired release of fibrinopeptide A (FPA) and a polymerization abnormality. In the accompanying article we have identified the amino acid substitution in fibrinogen Manchester as A alpha 16 Arg leads to His. When fibrinogen Manchester was digested with low thrombin concentrations approximately 40-50% of the total FPA content was release at a rate similar to FPA release from normal fibrinogen. The fibrin so formed exhibited an impaired polymerization of monomers. Digestion of fibrinogen Manchester with high concentrations of thrombin for prolonged times released the remaining FPA which had an abnormal retention time when studied by high performance liquid chromatography (HPLC). This fibrinopeptide has been shown previously to contain the A alpha 16 Arg leads to His substitution. fibrin resulting from this exhaustive digestion had normal polymerization of monomers. The normal and substituted FPAs were isolated by HPLC and compared in a double antibody competitive-binding assay for normal FPA. The immunological cross-reactivity of the abnormal peptide was reduced, so that approximately 5 times more abnormal peptide was required on a molar basis to displace labelled normal FPA. Normal intact fibrinogen was 10-fold less reactive (on a half molar basis) than free normal FPA and the crossreactivity of fibrinogen Manchester was measurably less than that of normal fibrinogen. It is concluded that immunological measurement alone of FPA released from abnormal fibrinogens may not give a complete description of the kinetics of peptide release if the amino acid substitution lies within the FPA sequence. The combination of radioimmunoassay and HPLC, however, provides a powerful analytical approach that should be useful in classifying and characterizing abnormal fibrinogens.

Recognition site for the platelet receptor is present on the 15-residue carboxy-terminal fragment of the γ chain of human fibrinogen and is not involved in the fibrin polymerization reaction

A pentadecapeptide, derived from a staphylococcal protease digest of the 27-residue carboxy-terminal cyanogen bromide fragment of human fibrinogen γ chain, inhibits binding of 125I-fibrinogen to human platelet receptors and aggregation of platelets induced by ADP and fibrinogen. Amino acid composition and NH 2 terminal analysis indicate that the isolated pentadecapeptide corresponds to residues 397 to 411 of the γ chain. A synthetic peptide also inhibited binding of 125I-fibrinogen and aggregation of platelets. In contrast, the isolated pentadecapeptide and its parent 27-residue fragment lack inhibitory activity toward the polymerization reaction of fibrin monomer. Thus, the site recognizing the platelet receptor encompasses residues 397–411 of the γ chain of fibrinogen and is distinct from the site(s) involved in polymerization of fibrin monomers.

Idiopathic autoantibody that inhibits fibrin monomer polymerization

A 73-year-old female was found to have prolonged thrombin and reptilase times in the immediate post-operative period. These abnormalities were not corrected by the addition of normal plasma. They were subsequently shown to be due to an IgG immunoglobulin which inhibited fibrin monomer polymerization. The IgG immunoglobulin activity could be neutralized completely by prior incubation with either patient or normal fibrinogen, uncrosslinked fibrin monomers or IgG antisera. No inhibitory effect on thrombin activity, fibrinopeptide A release or on the fibrin cross-linking reaction of factor XIIIa could be detected. Purified patient fibrinogen was functionally normal as demonstrated by normal fibrinogen-fibrin polymerization and fibrinopeptide A release. No underlying cause for this phenomenon was found. The presence of the inhibitor was associated with excessive blood loss during the post-operative period.

Effects of divalent cations on the conversion of fibrinogen to fibrin and fibrin polymerization.

Effects of divalent cations on fibrinogen and its reaction with thrombin were re-examined and correlated to improve definition of mechanisms underlying the acceleration of clot formation by the ions. The rate of release of fibrinopeptides from fibrinogen was not affected by any of the specific ions studied, but increased rates of fibrin monomer polymerization were obtained with all but magnesium ions. Maximal acceleration of monomer polymerization was observed with the divalent ions at concentration of 2.5-5 mM, and no added specific ion effects were observed with much higher levels. The acceleratory ions were found to have a corresponding effect on the solubility of fibrinogen, as judged from acceleration of its precipitation at low temperature. Although magnesium ions had no effect on fibrin monomer polymerization, they did have a low ranking effect on cryoprecipitation. These data confirm that the principal effect of divalent cations in the fibrinogen-fibrin transformation is to accelerate fibrin monomer polymerization, and suggest that the acceleration is associated with effects on the solubility of fibrinogen.