scholarly journals Labeling fibrin fibers with microparticle sized beads alter single fibrin fiber lysis, external clot lysis, and produce large fibrin aggregates upon lysis

2021 ◽  
Author(s):  
Christine Helms ◽  
Najnin Rimi
Keyword(s):  
Blood Clot ◽  
Fibrin Clot ◽  
Careful Consideration ◽  
Clot Lysis ◽  
Fiber Density ◽  
Force Microscopy ◽  
Fluorescent Beads ◽  
Fibrin Fiber ◽  
And Behavior ◽  
Clot Structure

Background Fluorescent beads are often used as a tool for visualizing fibrin fibers and can mimic the size of microparticles in the blood. Studies showed microparticles alter the appearance and behavior of whole blood clot systems. Objectives Here we investigate the effect of beads on fibrin fiber lysis and extensibility to enhance understanding of this common research technique and as a biomimetic system for fibrin-microparticle interaction. Methods We used fluorescence microscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM) to quantify changes in lysis, extensibility, and clot structure of fibrin fibers and clots in the presence and absence of beads. Results and Conclusions Fibrin clot structure and lysis were altered in the presence of beads. Fibrin clots formed with beads had a higher fiber density, smaller fibers, and smaller pores. The rate of lysis for clots was reduced when beads were present. Lysis of bead-labeled individual fibers showed that beads, at concentrations similar to those reported for microparticles in the blood, cause a subset of fibers to resist lysis. In the absence of beads, all fibers lyse. These results demonstrate that beads alter fiber lysis through both a change in fibrin clot structure as well as changes to individual fiber lysis behavior. Additionally, the lysis of clots with beads produced large fibrin aggregates. This data encourages researchers to use careful consideration when labeling fibrin fibers with fluorescent beads and suggests that particles binding fibrin(ogen) in the bloodstream may be an underappreciated mechanism increasing the risk of thrombosis.

The Interactions of Fibrin and Endothelial Cells within a Fibrin Clot

1997 ◽  
Vol 3 (S2) ◽  
pp. 233-234
Author(s):  
W. G. Jerome ◽  
R.R. Hantgan ◽  
S. Handt
Keyword(s):  
Endothelial Cells ◽  
Blood Clot ◽  
Direct Interaction ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Heart Attacks ◽  
Microscopic Studies ◽  
Life Threatening ◽  
Inhibitory Molecules ◽  
Clot Structure

A life threatening blood clot is the major cause of heart attacks. Thrombolytic therapy attempts to restore blood flow by activating the body's own fibrinolytic system at the site of the occlusive thrombus. However, for unknown reasons, therapy is unsuccessful in greater than 20% of patients. We have previously shown that the endothelial cells lining the wall of the vessel can play a substantial role in inhibiting clot lysis. This is due chiefly to the secretion of inhibitory molecules by endothelial cells. However, endothelial cells also have receptors for fibrin and little is known about how the direct interaction of fibrin with cells may influence lysis. To investigate this we have undertaken a series of microscopic studies to analyse the influence of endothelial cells on clot structure. We report here that endothelial cells can organize clot fibers into tight assemblies. We also show that, at least in culture, fibrin can act in concert with antithrombotic molecules to dramatically affect endothelial structure

Effect of Tranexamic Acid on Coagulation and Fibrin Clot Properties in Children Undergoing Craniofacial Surgery

2020 ◽  
Vol 120 (03) ◽  
pp. 392-399 ◽  
Author(s):  
Christian Fenger-Eriksen ◽  
Alexander D'Amore Lindholm ◽  
Lisbeth Krogh ◽  
Tobias Hell ◽  
Martin Berger ◽  
...  
Keyword(s):  
Data Analysis ◽  
Blood Loss ◽  
Tranexamic Acid ◽  
Thrombin Generation ◽  
Blood Clot ◽  
Fibrin Clot ◽  
Clot Formation ◽  
Clot Lysis ◽  
Clot Strength ◽  
Clot Structure

Abstract Objective Craniosynostosis surgery in small children is very often associated with a high blood loss. Tranexamic acid (TXA) reduces blood loss during this procedure, although the potential underlying coagulopathy in these children is not known in detail. Objective was to determine the nature of any coagulopathy found during and after craniosynostosis surgery and to characterize the effect of TXA on fibrin clot formation, clot strength, and fibrinolysis. Materials and Methods Thirty children received either TXA (bolus dose of 10 mg/kg followed by 8 hours continuous infusion of 3 mg/kg/h) or placebo. Dynamic whole blood clot formation assessed by thromboelastometry, platelet count, dynamic thrombin generation/thrombin-antithrombin, clot lysis assay, and fibrinogen/factor XIII (FXIII) levels were measured. Additionally, clot structure was investigated by real-time live confocal microscopy and topical data analysis. Results Increased ability of thrombin generation was observed together with a tendency toward shortened activated partial thromboplastin time and clotting time. Postoperative maximum clot firmness was higher among children receiving TXA. FXIII decreased significantly during surgery in both groups.Resistance toward tissue plasminogen activator-induced fibrinolysis was higher in children that received TXA, as evidenced by topical data analysis and by a significant longer lysis time. Fibrinogen levels were higher in the TXA group at 24 hours. Conclusion A significant coagulopathy mainly characterized by changes in clot stability and not parameters of thrombin generation was reported. Tranexamic acid improved clot strength and reduced fibrinolysis, thereby avoiding reduction in fibrinogen levels.

scholarly journals Contribution of Red Blood Cells and Clot Structure to Thrombosis

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. SCI-15-SCI-15
Author(s):  
Robert A S Ariens
Keyword(s):  
Atomic Force Microscopy ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Splice Variant ◽  
Blood Clot ◽  
Fibrin Clot ◽  
Force Microscopy ◽  
Atomic Force ◽  
Fibrin Network ◽  
Clot Structure

Abstract The blood clot or thrombus is composed of red blood cells, platelets and white cells that interact with the fibrin meshwork produced by the coagulation system. The red blood cells form polyhedrocytes that seal the clot, platelets provide forces for clot contraction, and white cells contribute neutrophil extracellular traps, cytokines and complement activation. The fibrin network contributes clot elasticity and provides the proteinaceous backbone structure that stabilises the clot. Previous studies from our laboratory and others have shown that dense fibrin networks demonstrating small pores and increased resistance to fibrinolysis associate with thrombosis. However, the mechanisms underpinning this have not been fully understood. Recent studies using atomic force microscopy from our laboratory have shown that fibrinogen interacts with red cells with comparable affinity as that with platelets. A patient with mutations in the β3 integrin subunit showed no binding between red cells and fibrinogen, demonstrating that a β3-related integrin receptor is involved in the interaction. Mutations in the fibrinogen α-chain integrin binding sites (D97E and D574E) reduced frequency of red cell interactions with fibrinogen. Interestingly, a naturally occuring splice variant of the fibrinogen γ-chain that reduces binding to the platelets, fibrinogen γ', increased binding interactions between fibrinogen and red blood cells. Fibrinogen γ' is a naturally occurring splice variant of fibrinogen, in which the C-terminal AGDV residues of the more common γA-chain (85%) are replaced with a negatively charched VRPEHPAETEYDSLYPEDDL sequence of the γ' chain (15%). Fibrinogen γ' induced clustering of fibrin fibres into tightly interknit nuclei of fibrin fibres, interspersed by large pores that extend over more than 50 μm within the fibrin network structure. The effects of fibrinogen γ' on fibrin clot structure was independent of thrombin and FXIII as demonstrated using snake venom enzyme. Previously we showed impaired fibrin protofibril formation with fibrinogen γ' using atomic force microscopy. Using turbidimetric analysis of fibrin intrafibrillar structure, we show that fibrinogen γ' reduces protofibil packing per fibrin fiber. Furthermore, we find that reduced protofibril packing diminishes fibrin stiffness as analysed with magnetic tweezers both in purified systems as well as in plasma at (patho)physiological fibrinogen γ' levels that range from 3-40%, and in whole blood as analysed with thromboelastography. In conclusion, our data show that red blood cells and fibrinogen γ' play major roles in the regulation of clot structure and stability, and that these effects on clot structure are major determinants of the functional properties of the blood clot. Modulating fibrin clot structure and its interactions with blood cells may represent major new targets for the treatment of thrombosis. Disclosures No relevant conflicts of interest to declare.

Altered fibrin clot structure/function in patients with antiphospholipid syndrome: association with thrombotic manifestation

2014 ◽  
Vol 112 (08) ◽  
pp. 287-296 ◽  
Author(s):  
Magdalena Celińska-Löwenhoff ◽  
Teresa Iwaniec ◽  
Agnieszka Padjas ◽  
Jacek Musiał ◽  
Anetta Undas
Keyword(s):  
Structure Function ◽  
Antiphospholipid Syndrome ◽  
Thrombotic Event ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Lag Phase ◽  
Lysis Time ◽  
Clot Structure ◽  
Clot Lysis Time ◽  
D Dimer

SummaryWe tested the hypothesis that plasma fibrin clot structure/function is unfavourably altered in patients with antiphospholipid syndrome (APS). Ex vivo plasma clot permeability, turbidity and susceptibility to lysis were determined in 126 consecutive patients with APS enrolled five months or more since thrombotic event vs 105 controls. Patients with both primary and secondary APS were characterised by 11% lower clot permeability (p<0.001), 4.8% shorter lag phase (p<0.001), 10% longer clot lysis time (p<0.001), and 4.7% higher maximum level of D-dimer released from clots (p=0.02) as compared to the controls. Scanning electron microscopy images confirmed denser fibrin networks composed of thinner fibres in APS. Clots from patients with “triple-antibody positivity” were formed after shorter lag phase (p=0.019) and were lysed at a slower rate (p=0.004) than in the remainder. Clots from APS patients who experienced stroke and/or myocardial infarction were 8% less permeable (p=0.01) and susceptible to lysis (10.4% longer clot lysis time [p=0.006] and 4.5% slower release of D-dimer from clots [p=0.01]) compared with those following venous thromboembolism alone. Multivariate analysis adjusted for potential confounders showed that in APS patients, lupus anticoagulant and “triple-positivity” were the independent predictors of clot permeability, while “triple-positivity” predicted lysis time. We conclude that APS is associated with prothrombotic plasma fibrin clot phenotype, with more pronounced abnormalities in arterial thrombosis. Molecular background for this novel prothrombotic mechanism in APS remains to be established.

Plasma fibrin clot properties in the G20210A prothrombin mutation carriers following venous thromboembolism: the effect of rivaroxaban

2017 ◽  
Vol 117 (09) ◽  
pp. 1739-1749 ◽  
Author(s):  
Agnieszka Janion-Sadowska ◽  
Joanna Natorska ◽  
Jakub Siudut ◽  
Michal Zabczyk ◽  
Andrzej Stanisz ◽  
...  
Keyword(s):  
Venous Thromboembolism ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Mutation Carriers ◽  
Lysis Time ◽  
Prothrombin Mutation ◽  
Fibrinolysis Inhibitor ◽  
Heterozygous Carriers ◽  
Mutation Group ◽  
Clot Structure

SummaryWe sought to investigate whether the G20210A prothrombin mutation modifies plasma fibrin clot properties in patients after venous thromboembolism (VTE) and how rivaroxaban treatment affects these alterations. We studied 34 prothrombin mutation heterozygous carriers and sex- and age-matched 34 non-carriers, all at least three months since the first VTE episode, before and during treatment with rivaroxaban. Clot permeability (Ks) and clot lysis time (CLT) with or without elimination of thrombin activatable fibrinolysis inhibitor (TAFI) were assessed at baseline, 2–6 hours (h) after and 20–25 h after intake of rivaroxaban (20 mg/day). At baseline, the prothrombin mutation group formed denser clots (Ks −12 %, p=0.0006) and had impaired fibrinolysis (CLT +14 %, p=0.004, and CLT-TAFI +13 %, p=0.03) compared with the no mutation group and were similar to those observed in 15 healthy unrelated prothrombin mutation carriers. The G20210A prothrombin mutation was the independent predictor for Ks and CLT before rivaroxaban intake. At 2–6 h after rivaroxaban intake, clot properties improved in both G20210A carriers and non-carriers (Ks +38 %, and +37 %, CLT −25 % and −25 %, CLT-TAFI −20 % and −24 %, respectively, all p<0.001), but those parameters were worse in the prothrombin mutation group (Ks −12.8 %, CLT +17 %, CLT-TAFI +13 %, all p<0.001). Rivaroxaban concentration correlated with fibrin clot properties. After 20–25 h since rivaroxaban intake most clot properties returned to baseline. Rivaroxaban-related differences in clot structure were confirmed by scanning electron microscopy images. In conclusion, rivaroxaban treatment, though improves fibrin clot properties, cannot abolish more prothrombotic fibrin clot phenotype observed in prothrombin mutation carriers following VTE.

Altered fibrin clot structure contributes to thrombosis risk in severe COVID-19

2021 ◽  
Author(s):  
Malgorzata Wygrecka ◽  
Anna Birnhuber ◽  
Benjamin Seeliger ◽  
Laura Michalick ◽  
Oleg Pak ◽  
...  
Keyword(s):  
Thrombus Formation ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Factor Xii ◽  
Tissue Sections ◽  
Thrombosis Risk ◽  
Activation Rate ◽  
Activation Products ◽  
Kaolin Clotting Time ◽  
Clot Structure

The high incidence of thrombotic events suggests a possible role of the contact system pathway in COVID-19 pathology. Here, we demonstrate altered levels of factor XII (FXII) and its activation products in two independent cohorts of critically ill COVID-19 patients in comparison to patients suffering from severe acute respiratory distress syndrome due to influenza virus (ARDS-influenza). Compatible with this data, we report rapid consumption of FXII in COVID-19, but not in ARDS-influenza, plasma. Interestingly, the kaolin clotting time was not prolonged in COVID-19 as compared to ARDS-influenza. Using confocal and electron microscopy, we show that increased FXII activation rate, in conjunction with elevated fibrinogen levels, triggers formation of fibrinolysis-resistant, compact clots with thin fibers and small pores in COVID-19. Accordingly, we observed clot lysis in 30% of COVID-19 patients and 84% of ARDS influenza subjects. Analysis of lung tissue sections revealed wide-spread extra- and intra-vascular compact fibrin deposits in COVID-19. Together, our results indicate that elevated fibrinogen levels and increased FXII activation rate promote thrombosis and thrombolysis resistance via enhanced thrombus formation and stability in COVID-19.

Factor XIIa regulates the structure of the fibrin clot independently of thrombin generation through direct interaction with fibrin

Blood ◽  
2011 ◽  
Vol 118 (14) ◽  
pp. 3942-3951 ◽  
Author(s):  
Joke Konings ◽  
José W. P. Govers-Riemslag ◽  
Helen Philippou ◽  
Nicola J. Mutch ◽  
Julian I. Borissoff ◽  
...  
Keyword(s):  
Thrombin Generation ◽  
Thrombus Formation ◽  
Coagulation Factor ◽  
Direct Interaction ◽  
Fibrin Clot ◽  
Fiber Density ◽  
Contact Pathway ◽  
Clot Structure ◽  
Fibrin Structure

Abstract Recent data indicate an important contribution of coagulation factor (F)XII to in vivo thrombus formation. Because fibrin structure plays a key role in clot stability and thrombosis, we hypothesized that FXII(a) interacts with fibrin(ogen) and thereby regulates clot structure and function. In plasma and purified system, we observed a dose-dependent increase in fibrin fiber density and decrease in turbidity, reflecting a denser structure, and a nonlinear increase in clot stiffness with FXIIa. In plasma, this increase was partly independent of thrombin generation, as shown in clots made in prothrombin-deficient plasma initiated with snake venom enzyme and in clots made from plasma deficient in FXII and prothrombin. Purified FXII and α-FXIIa, but not β-FXIIa, bound to purified fibrinogen and fibrin with nanomolar affinity. Immunostaining of human carotid artery thrombi showed that FXII colocalized with areas of dense fibrin deposition, providing evidence for the in vivo modulation of fibrin structure by FXIIa. These data demonstrate that FXIIa modulates fibrin clot structure independently of thrombin generation through direct binding of the N-terminus of FXIIa to fibrin(ogen). Modification of fibrin structure by FXIIa represents a novel physiologic role for the contact pathway that may contribute to the pathophysiology of thrombosis.

Polyphosphate Enhances Fibrin Clot Structure.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 403-403
Author(s):  
Stephanie A. Smith ◽  
James H. Morrissey
Keyword(s):  
High Energy ◽  
Fibrin Clot ◽  
Clot Formation ◽  
Length Ratio ◽  
Factor Xiiia ◽  
Clot Lysis ◽  
Cross Linking ◽  
Inorganic Polyphosphate ◽  
Calcium Dependent ◽  
Clot Structure

Abstract Introduction: Inorganic polyphosphate (polyP) is a negatively charged polymer of phosphate units linked by high energy phosphoanhydride bonds. Dense granules of human platelets contain polyP which is released in response to thrombin stimulation. We recently reported that polyphosphate is a potent hemostatic regulator, accelerating blood clotting by activating the contact pathway and promoting the activation of factor V. Our previous studies found that polyP did not affect the time to clot formation when plasma was clotted with thrombin, however, suggesting that polyP exerts its procoagulant actions upstream of thrombin. We now report that polyP enhances fibrin clot structure. Methods: Purified fibrinogen and polyP were preincubated for 15 min in multiwell plates in buffer containing CaCl2, after which clotting was initiated by adding 0.1 to 8 nM thrombin and fibrin clot formation was evaluated by quantifying the change in turbidity (A405). Mass-length ratios were calculated from scans of A400 to A800. The effect of polyP on fibrinolysis was examined by adding 8 nM plasmin to the reaction mixtures immediately prior to thrombin. Scanning electron microscopy (SEM) was employed to visualize clot structure, and time courses of covalent fibrin cross-linking were assessed by SDS-PAGE. Results: PolyP had no effect on time to clot formation, but clots formed in the presence of polyP had markedly (up to threefold) higher turbidity than clots formed in the absence of polyP (see figure), irrespective of thrombin concentration. The increased turbidity in the presence of polyP was calcium-dependent and was enhanced when fibrinogen, CaCl2, and polyP were preincubated for up to 15 min prior to initiation of clotting with thrombin. PolyP increased the mass-length ratio of fibrin, and SEM confirmed that fibers formed with polyP were thicker than those formed without polyP. The ability of polyP to enhance fibrin clot turbidity was independent of factor XIIIa activity, and polyP did not alter the rate or extent of covalent fibrin cross-linking by factor XIIIa. When plasmin was included in clotting reactions containing polyP, mean times to 50% clot lysis were 28.5 ± 0.8 min for clots without polyP but 120.4 ± 5.6 min for clots with polyP. Conclusions: PolyP alters polymerization of fibrin, resulting in fibers of higher mass-length ratio that are lysed more slowly. This effect is calcium-dependent and is enhanced by preincubation of fibrinogen with calcium and polyP. Release of polyP from activated platelets or infectious microorganisms may therefore enhance fibrin clot structure. Figure Figure

scholarly journals Dusart syndrome: a new concept of the relationship between fibrin clot architecture and fibrin clot degradability: hypofibrinolysis related to an abnormal clot structure

Blood ◽  
1993 ◽  
Vol 82 (8) ◽  
pp. 2462-2469 ◽  
Author(s):  
JP Collet ◽  
J Soria ◽  
M Mirshahi ◽  
M Hirsch ◽  
FB Dagonnet ◽  
...  
Keyword(s):  
Blood Clot ◽  
Fibrin Clot ◽  
Important Change ◽  
High Incidence ◽  
Gel Porosity ◽  
Clot Structure ◽  
The Relationship ◽  
Dose Dependent ◽  
Thrombotic Disorder

Fibrinogen Dusart is a congenital dysfibrinogenemia (A-alpha 554 Arginine-->Cysteine) associated with severe thrombotic disorder, high incidence of thrombotic embolism, and abnormal fibrin polymerization. This thrombotic disorder was attributed to an abnormal clot thrombolysis with reduced plasminogen binding to fibrin and defective plasminogen activation by tissue plasminogen activator. The purpose of this work was to assess whether clot architecture could be involved in the thromboresistance of the fibrin Dusart and the high incidence of embolism. An important change in Dusart fibrin clot structure was identified with dramatic decrease of gel porosity (Ks), fiber diameters (d), and fiber mass-length ratios (mu) derived from permeation analysis. In addition, rigidity of the Dusart clot was found to be greatly increased compared with normal fibrin. We provide evidence that both thrombolysis resistance and abnormal rigidity of the fibrin Dusart are related to this abnormal architecture, which impairs the access of fibrinolytic enzymes to the fibrin and which is responsible for a brittle clot that breaks easily, resulting in a high incidence of embolism. Indeed, when restoring a normal clot structure by adding dextran 40 (30 mg/mL) before coagulation, clot thrombolysis and clot rigidity recovered normal values. This effect was found to be dose- dependent. We conclude that clot architecture is crucial for the propensity of blood clot to be degraded and that abnormal clot structure can be highly thrombogenic in vivo. The alpha-C domains of fibrinogen are determinant in fibrin clot structure.

The vulnerable blood

2015 ◽  
Vol 35 (01) ◽  
pp. 25-33 ◽  
Author(s):  
K. Hess
Keyword(s):  
Platelet Function ◽  
Plaque Rupture ◽  
Coagulation Factors ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Complement Components ◽  
Cardiovascular Morbidity And Mortality ◽  
Increased Risk ◽  
Patients With Diabetes ◽  
Clot Structure

SummaryPatients with diabetes are at increased risk of cardiovascular morbidity and mortality. While arteriosclerotic lesions have long been recognized as the underlying cause more recent studies suggest that alterations of the blood are also critically involved. Following plaque rupture, adherence of platelets is followed by the formation of a cross-linked fibrin clot. Patients with diabetes exhibit a prothrombotic milieu consisting of hyper reactive platelets, a tight and rigid clot structure which is due to up-regulation of coagulation factors and prolongation of clot lysis. Metabolic alterations as well as inflammatory processes, which are up–regulated in diabetes, are thought to be the main underlying causes. More recently, the complement cascade has emerged as a potential new player in this context with several complement components directly influencing both platelet function and coagulation.This review provides an overview concerning the changes that lead to alterations of platelet function and clot structure in diabetes.

Sign in / Sign up

Export Citation Format

Share Document