Effect of oxidized fibrinogens on blood coagulation

Post-translational modifications of fibrinogen: implications for clotting, fibrin structure and degradation

Fibrinogen, a blood plasma protein with a key role in hemostasis and thrombosis, is highly susceptible to post-translational modifications (PTMs), that significantly influence clot formation, structure, and stability. These PTMs, which include acetylation, amidation, carbamylation, citrullination, dichlorination, glycation, glycosylation, guanidinylation, hydroxylation, homocysteinylation, malonylation, methylation, nitration, oxidation, phosphorylation and sulphation, can alter fibrinogen biochemical properties and affect its functional behavior in coagulation and fibrinolysis. Oxidation and nitration are notably associated with oxidative stress, impacting fibrin fiber formation and promoting the development of more compact and resistant fibrin networks. Glycosylation and glycation contribute to altered fibrinogen structural properties, often resulting in changes in fibrin clot density and susceptibility to lysis, particularly in metabolic disorders like diabetes. Acetylation and phosphorylation, influenced by medications such as aspirin, modulate clot architecture by affecting fiber thickness and clot permeability. Citrullination and homocysteinylation, although less studied, are linked to autoimmune conditions and cardiovascular diseases, respectively, affecting fibrin formation and stability. Understanding these modifications provides insights into the pathophysiology of thrombotic disorders and highlights potential therapeutic targets. This review comprehensively examines the current literature on fibrinogen PTMs, their specific sites, biochemical pathways, and their consequences on fibrin clot architecture, clot formation and clot lysis.

Reduced protein carbonylation on hormone therapy is associated with improved fibrinolysis in postmenopausal women: the impact of PAI-1 and TAFI activity

Hormone therapy (HT) has been reported to reduce protein carbonylation (PC) in postmenopausal women, in whom fibrinolysis is impaired. We investigated whether PC affects fibrinolysis and if HT modulates this effect. We enrolled 150 women aged 55.5 ± 4.7 years in a randomized interventional open-label study, including 50 on standard oral HT, 50 on ultra-low-dose HT, and 50 controls. PC, along with global fibrinolysis (clot lysis time, CLT), fibrinolysis proteins, and prothrombotic markers were determined at baseline and at 24 weeks. Patients with the baseline top quartile PC (> 2.07 nM/mg protein) had 10.3% longer CLT, higher activity (but not antigen) of TAFI (+ 19.9%) and PAI-1 (+ 68.1%) compared to the remainder. No differences were observed in thrombin generation, factor VIII, plasminogen or α2-antiplasmin. On-treatment PC decreased by 16.4% (p < 0.0001), without differences related to the type of HT, compared to baseline and by 30% compared to controls, in whom PC and fibrinolysis markers remained unchanged. Patients with PC > 2.07 nM/mg had shortened CLT during HT compared to baseline, along with lower PAI-1 (-69%) and TAFI (-26%) activity. In this subgroup CLT was 5.8% shorter compared to controls with the highest PC. In postmenopausal women with increased PC, HT was accompanied by PC reduction and faster clot lysis together with decreased PAI-1 and TAFI activity.

Oxidative stress-induced fibrinogen modifications in liver transplant recipients: unraveling a novel potential mechanism for cardiovascular risk

Background

Cardiovascular events represent a major cause of non-graft-related death after liver transplant. Evidence suggest that chronic inflammation associated with a remarkable oxidative stress in the presence of endothelial dysfunction and procoagulant environment plays a major role in the promotion of thrombosis. However, the underlying molecular mechanisms are not completely understood.

Objectives

In order to elucidate the mechanisms of posttransplant thrombosis, the aim of the present study was to investigate the role of oxidation-induced structural and functional fibrinogen modifications in liver transplant recipients.

Methods

A case-control study was conducted on 40 clinically stable liver transplant recipients and 40 age-matched, sex-matched, and risk factor-matched controls. Leukocyte reactive oxygen species (ROS) production, lipid peroxidation, glutathione content, plasma antioxidant capacity, fibrinogen oxidation, and fibrinogen structural and functional features were compared between patients and controls.

Results

Patients displayed enhanced leukocyte ROS production and an increased plasma lipid peroxidation with a reduced total antioxidant capacity compared with controls. This systemic oxidative stress was associated with fibrinogen oxidation with fibrinogen structural alterations. Thrombin-catalyzed fibrin polymerization and fibrin resistance to plasmin-induced lysis were significantly altered in patients compared with controls. Moreover, steatotic graft and smoking habit were associated with high fibrin degradation rate.

Conclusion

ROS-induced fibrinogen structural changes might increase the risk of thrombosis in liver transplant recipients.

UV induced changes in proteome of rats plasma are reversed by dermally applied cannabidiol

UV radiation is known to induce a multiple changes in the metabolism of skin-building cells, what can affect the functioning not only neighboring cells, but also, following signal transduction releasing into the blood vessels, the entire body. Therefore, the aim of this study was to analyze the proteomic disturbances occurred in plasma of chronically UVA/UVB irradiated rats and define the effect on these changes of skin topically applied cannabidiol (CBD). Obtained results showed significant changes in the expression of numerous anti-inflammatory and signaling proteins including: NFκB inhibitor, 14-3-3 protein, protein kinase C, keratin, and protein S100 after UV irradiation and CBD treatment. Moreover, the effects of UVA and UVB were manifested by increased level of lipid peroxidation products-protein adducts formation. CBD partially prevented all of these changes, but in a various degree depending on the UV radiation type. Moreover, topical treatment with CBD resulted in the penetration of CBD into the blood and, as a consequence, in direct modifications to the plasma protein structure by creating CBD adducts with molecules, such as proline-rich protein 30, transcription factor 19, or N-acetylglucosamine-6-sulfatase, what significantly changed the activity of these proteins. In conclusion, it may be suggested that CBD applied topically may be an effective compound against systemic UV-induced oxidative stress, but its effectiveness requires careful analysis of CBD's effects on other tissues of the living organism.

Oxidative Stress and Preeclampsia-Associated Prothrombotic State

Preeclampsia (PE) is a common obstetric disease characterized by hypertension, proteinuria, and multi-system dysfunction. It endangers both maternal and fetal health. Although hemostasis is critical for preventing bleeding complications during pregnancy, delivery, and post-partum, PE patients often develop a severe prothrombotic state, potentially resulting in life-threatening thrombosis and thromboembolism. The cause of this thrombotic complication is multi-factorial, involving endothelial cells, platelets, adhesive ligands, coagulation, and fibrinolysis. Increasing evidence has shown that hemostatic cells and factors undergo oxidative modifications during the systemic inflammation found in PE patients. However, it is largely unknown how these oxidative modifications of hemostasis contribute to development of the PE-associated prothrombotic state. This knowledge gap has significantly hindered the development of predictive markers, preventive measures, and therapeutic agents to protect women during pregnancy. Here we summarize reports in the literature regarding the effects of oxidative stress and antioxidants on systemic hemostasis, with emphasis on the condition of PE.

Effects of Post-Translational Modifications of Fibrinogen on Clot Formation, Clot Structure, and Fibrinolysis: A Systematic Review

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Post-translational modifications of fibrinogen influence the occurrence and progression of thrombotic diseases. In this systematic review, we assessed the current literature on post-translational modifications of fibrinogen and their effects on fibrin formation and clot characteristics.

Effect of oxidatively modified and non-modified human serum albumin on luminol-dependent chemiluminescence of human peripheral blood leukocytes stimulated with opsonized zymosan

We studied the effects of native and oxidized human serum albumin on luminol-dependent chemiluminescence of human peripheral blood leukocytes stimulated with opsonized zymosan. Human serum albumin was added simultaneously with opsonized zymosan at the beginning of the chemiluminescent reaction. Otherwise, leukocytes were incubated with human serum albumin at 37°C for various periods before addition of opsonized zymosan. Oxidized human serum albumin was obtained by the method of metal-catalyzed oxidation. In control to non-modified albumin, oxidized albumin produced an inhibitory effect on luminol-dependent chemiluminescence of leukocytes. These changes were observed in experiments with addition of oxidized albumin at the beginning of a chemiluminescent reaction and after incubation of study agent with cells.

Effect of oxidation-modified fibrinogen on the formation and lysis of fibrin clot in the plasma

Turbidimetry studies showed that after addition of thrombin to fresh donor plasma light scatter in the sample increases and slowly attains a plateau. The process of fibrin formation was less intensive in the presence of oxidized fibrinogen. The formation of fibrin clot in lyophilized plasma was characterized by a biphasic kinetic of light scatter, oxidized fibrinogen inhibited both phases of the process. In the presence of streptokinase, oxidized fibrinogen did not modify the kinetics of fibrin clot lysis. Addition of oxidized fibrinogen to plasma reduced optical density of fibrin clot the more intensely the higher was the degree of oxidative modification of fibrinogen.

Effect of Oxidized Fibrinogen on Hemostatic System: In Vitro Study

Standard coagulation assays were performed with control and oxidized fibrinogen (Fg), using prothrombin time (PT; 12.5 ± 0.4 vs 25 ± 0.8 seconds, P < .001) and activated partial thromboplastin time (aPTT; 33 ± 2.5 vs 63 ± 4.7 seconds, P < .001). Fibrin clot (MA), clot formation initiation (r), and rate of clot lysis (LY30) were measured, a reflection exposure of Fg to Fe3+/ ascorbate oxidative system by thrombelastograph (TEG) analysis (0, 6, 12, 24, and 48 hours, 6.2 ± 1.3 vs 5.5 ± 1.2, 4.3 ± 1.0 [P < .01], 3.9 ± 1.6, 3.2 ± 0.8, [P < .001]). Maximum amplitude level was found to be lower than control (69.1 ± 7.2 vs 67.9 ± 12.4, 64.0 ± 11.4, 60.2 ± 21.2, 42.2 ± 15.2, P < .001). The lysis rate was changed according to oxidation time between Fg exposed to Fe3+/ascorbate and control exposed to Fe 3+/ascorbate for the same treatment time (1.9 ± 0.71 vs 7 ± 0.5, 1.6 ± 0.1, 1.2 ± 0.5, 0.9 ± 1.3, P < .001). We revealed dysregulation of hemostatic system with contribution of oxidized Fg, which was in direct proportion to the intensity of Fg oxidation.

Oxidative Modification of Fibrinogen Affects Its Binding Activity to Glycoprotein (GP) IIb/IIIa

Aim: Proteins are sensitive biomarkers of human diease condition associated with oxidative stress. Alteration of protein structures by oxidants may result in partial or complete loss of protein functions. We have investigated the effect of structural modifications induced by metal ion catalyzed oxidation of fibrinogen on its binding capacity to glycoprotein IIb/IIIa (GpIIb/IIIa) and human platelets. Methods: We identified and quantified of binding capacity of native and oxidized fibrinogen to its receptor in vitro by flow cytometer. Dityrosine formation on oxidized fibrinogen were detected spectrophotometrically. Elevated degradation products of fibrinogen after oxidation were revealed in the HPLC analysis. The native and oxidized fibrinogen were analyzed on mass spectrum upon digestion with tyripsin. Results: Oxidatively modified fibrinogen showed less binding activity than native fibrinogen to GpIIb/IIIa coated micro beads and human platelets whereas slightly higher binding capaticity to ADP induced stimulated platelets. Formation of dityrosines in the amino acid side chains of fibrinogen were observed upon oxidation. Decreased binding capacity of oxidized fibrinogen correlated with intensities of dityrosine formation. Oxidized fibrinogen had more ion-mass intensities at higher than native fibrinogen. Clinical implications: Important point is decreased of binding capacity of the oxidized fibrinogen to own receptor. The decreased rate of binding, leading to effect in the diseases of clot formation may acount for the association between oxidation of fibrinogen and the incidence of effect in human diseases.

Effect of oxidized fibrinogen on aggregation of activated platelets and neutrophils

The effect of oxidized fibrinogen on platelet-neutrophil complex formation was evaluated by studying the platelet aggregation (changes in light transmission and turbidimetric assay). Activation of cells by thrombin (0.015 U/ml) in the presence of oxidized fibrinogen was accompanied by the formation of larger intermolecular aggregates of platelets and leukocytes as compared to those detected in experiments with non-oxidized fibrinogen. Addition of thrombin (0.2 U/ml) in the presence of oxidized fibrinogen was followed by the formation of more stable complexes of platelets and leukocytes as compared to those revealed in experiments with non-oxidized fibrinogen. An increase in the width of aggregation curves was most pronounced in the system of 10(-4) M Fe(2+) and 10(-4) M H(2)O(2) with oxidized fibrinogen. Our results indicate that oxidized fibrinogen contributes to the "floating" or suspension of platelet-leukocyte complexes.

Fibrinogen heterogeneity: inherited and noninherited

PURPOSE OF REVIEW

Many noninherited or inherited variations have been described in fibrinogen and they may affect the different functions of fibrinogen.

RECENT FINDINGS

A number of the acquired variations in fibrinogen affect the properties of the fibrinogen molecule, such as the conversion rate to fibrin and/or the characteristics of the fibrin clot. Also, genetic polymorphisms are known that can affect the function of the fibrinogen molecule. In addition, some other genetic variants are associated with plasma levels of fibrinogen and with the increase of fibrinogen levels during an acute-phase reaction.

SUMMARY

In this review the authors discuss the noninherited and inherited variations of fibrinogen and the clinical implications (e.g. when determining the risk of cardiovascular disease).