Plasma Fibrin Clot Research Articles

Enhanced neutrophil extracellular traps formation in AF patients with dilated left atrium.

Atrial fibrillation (AF) is associated with cardiac remodelling and prothrombotic state. Enhanced neutrophil extracellular traps (NETs) formation has been reported in AF, contributing to thromboembolism. We investigated whether increased left atrium (LA) diameter and reduced left ventricular ejection fraction (LVEF) affect NETs formation and prothrombotic state in AF patients. In 243 AF patients (median CHA2 DS2 -VASc=4) we measured LA diameter and LVEF, 123 of them with LVEF<50%. Moreover, we determined 3 markers of NETosis: circulating citrullinated histone H3 (H3cit), myeloperoxidase (MPO) and peptidylarginine deiminase 4 (PAD4), along with prothrombotic markers, including endogenous thrombin potential, plasma fibrin clot permeability (Ks ) and clot lysis time (CLT). Ischaemic cerebrovascular events, major bleeding and death were recorded during a median follow-up of 53 months, on anticoagulation. LA diameter correlated positively with H3cit, MPO and PAD4, while LVEF was inversely associated with the same NETosis markers. After adjustment for age and body mass index, concentrations of MPO (per 10units; β=-1.9, 95%CI -3.40;-0.42) and H3cit (per 10units; β=2.02, 95%CI 0.61-3.42) were independently associated with LVEF and LA diameter. LA diameter, but not LVEF, correlated inversely with Ks and positively with CLT. The Cox regression analysis revealed that H3cit >6.16 ng/mL (HR=21.76, 95%CI 2.85-166.28, p=.003) and LA diameter > 46 mm (HR=2.89, 95%CI 1.04-8.03, p=.043) independently predicted cerebrovascular ischaemic events (1.9%/year). This hypothesis-generating study suggests that in AF enlarged LA diameter and reduced LVEF are associated with enhanced NETs formation, which might have clinical importance and contribute to thromboembolic events despite anticoagulation.

Therapy with high-dose statins reduces soluble P-selectin: The impact on plasma fibrin clot properties

ObjectiveStudies on the effect of statins on platelets in patients with coronary artery disease (CAD) yielded inconsistent results. We sought to investigate whether high-dose statin therapy reduces plasma concentrations of soluble P-selectin (sP-selectin), a well-established platelet activation marker and if such changes can affect fibrin clot properties, which are unfavorably altered in CAD patients. MethodsWe studied 130 consecutive patients with advanced CAD who did not achieve the target LDL cholesterol on statins. At baseline and after 6–12 months of treatment with atorvastatin 80 mg/day or rosuvastatin 40 mg/day, soluble plasma sP-selectin, along with plasma fibrin clot permeability (Ks), clot lysis time (CLT), thrombin generation and fibrinolysis proteins were determined. ResultsBefore high-intensity statin treatment, lower Ks and longer CLT values were associated with increased sP-selectin (β −0.27 [95% CI -0.44 to −0.10] and β 0.21 [95% CI 0.01 to 0.41]; both p < 0.05, respectively) also after adjustment for potential confounders. sP-selectin, alongside fibrin features and other variables at baseline showed no association with lipid profile. On high-dose statin therapy, there was 32% reduction in sP-selectin levels (p < 0.001). On-treatment change (Δ) in sP-selectin correlated with ΔKs and ΔCLT (r = −0.32, p < 0.001 and r = 0.22, p = 0.011, respectively), but not with cholesterol and C-reactive protein lowering. We did not observe any associations between post-treatment sP-selectin levels and lipids, fibrin clot properties or thrombin generation. ConclusionsHigh-dose statin therapy reduces markedly sP-selectin levels in association with improved fibrin clot phenotype, which highlights the contribution of platelet-derived proteins to a prothrombotic state in hypercholesterolemia and statin-induced antithrombotic effects.

Changes in fibrinolytic activity and coagulation factors after epicardial left atrial appendage closure in patients with atrial fibrillation.

The left atrial appendage (LAA) is known to be the primary source of thrombus formation in atrial fibrillation (AF). We investigate whether epicardial LAA occlusion (LAAO) from the cardiovascular system has an effect on coagulation and prothrombotic status in AF. Twenty-two patients with nonvalvular AF, who were not currently receiving oral anticoagulation (OAC) therapy, participated in a single-center prospective study. We measured fibrinogen and plasminogen levels along with plasma fibrin clot permeability, clot lysis time (CLT) and endogenous thrombin potential (ETP) before the LAAO procedure, at discharge and 1 month afterward. One month after the LAAO procedure, plasma fibrin clot permeability improved by 39.3% as measured by clots prepared from peripheral blood (P=0.019) and also after adjustment for fibrinogen (P=0.027). Higher plasma fibrin clot permeability was associated with improved clot susceptibility to lysis (r=-0.67, P=0.013). CLT was reduced by 10.3% (P=0.0020), plasminogen activator inhibitor-1 antigen levels were reduced by 52% (P=0.023) and plasminogen activity was increased by 8.9% (P=0.0077). A trend toward decreased thrombin generation, reflected by a decreased ETP and peak thrombin generated was also observed 1 month after LAAO procedure (P=0.072 and P=0.087, respectively). No differences were observed in tissue-type plasminogen activator and thrombin-activatable fibrinolysis inhibitor plasma levels (both P>0.05). Obtained results seem to confirm that LAA plays a key role in thrombogenesis. Elimination of LAA from the circulatory system may improve fibrin clot permeability and susceptibility to fibrinolysis in peripheral blood.

Elevated 8-isoprostane concentration is associated with thromboembolic events in patients with atrial fibrillation

BackgroundEnhanced oxidative stress occurs in atrial fibrillation (AF), however its impact on the efficacy and safety of anticoagulation is unknown. We sought to evaluate whether 8-isoprostaglandin F2 (8-isoprostane) levels are associated with clinical outcomes in anticoagulated AF patients. MethodsIn a study involving 243 AF patients (median age 69 years), we measured serum 8-isoprostane, along with prothrombotic markers, including plasma fibrin clot permeability, clot lysis time (CLT), endogenous thrombin potential (ETP), von Willebrand factor (VWF), and fibrinolytic proteins. Ischemic cerebrovascular events, major bleeding, and death were recorded during a median follow-up of 53 months while on anticoagulation, largely on non-vitamin K antagonist oral anticoagulants (NOACs). ResultsIncreased 8-isoprostane levels were observed in women, in patients with arterial hypertension, and those with paroxysmal or persistent AF. Patients with 8-isoprostane levels ≥559 pg/mL (the top quartile) compared with those with 8-isoprostane <250 pg/mL (the bottom quartile) had higher fibrinogen, lower VWF, higher plasminogen activator inhibitor 1, along with lower fibrin clot permeability with no difference in CHA2DS2-VASc score, CLT or ETP. Patients who experienced thromboembolic events (n = 20, 1.9%/year) had 48.6% higher 8-isoprostane concentrations compared to the remainder (P <0.01). Levels of 8-isoprostane >459 pg/mL based on the optimal cut-off value were associated with thromboembolic events during follow-up (hazard ratio 2.87, 95% confidence interval 1.17–7.03, P = 0.02). There were no associations between 8-isoprostane and major bleeding (2.0%/year) or all-cause mortality (1.9%/year). ConclusionsIncreased 8-isoprostane levels partly through altered fibrin clot structure are associated with thromboembolic events despite anticoagulant therapy in AF patients.

GnRH Antagonist Protocol Enhances Coagulation During Controlled Ovarian Stimulation for IVF.

Changes in coagulation and fibrinolysis have been reported in women undergoing controlled ovarian hyperstimulation (COH) supporting a potential hypercoagulable condition related to this treatment. This study aimed at evaluating the changes in fibrin clot properties and thrombin generation induced by two different COH protocols: long with gonadotropin-releasing hormone agonist (GnRH-a) and GnRH antagonist (GnRH-ant). Primary outcomes included determination of plasma fibrin clot properties, including clot permeability (Ks) and efficiency of fibrinolysis using clot lysis time (CLT), along with thrombin generation (prothrombin fragments 1 + 2) and endogenous thrombin potential (ETP) and fibrinolysis inhibitor levels. One hundred twenty-nine infertile women were included in the final analysis. The GnRH-ant protocol resulted in increased ETP (+ 9.8%) and reduced Ks (- 2.4%). Conversely, COH with the GnRH-a protocol reduced thrombin generation by decreasing both ETP (- 6.6%) and F1 + 2 (- 30.8%) together with favorably altered fibrin clot properties represented by increased Ks (+ 21.7%) and reduced CLT (- 13.8%) as well as decreased PAI-1 levels (by 2.5 times). The GnRH-ant compared to the GnRH-a protocol increased PAI-1 levels (+ 77.3%), thrombin generation (9.3% higher ETP), and Ks (+ 13.7%). In the GnRH-a group, post-COH Ks was 14.3% higher (Ks ≥ 7.92 × 10-9 cm2) in women with positive vs. negative pregnancy outcomes. Our results show that the GnRH-ant protocol enhanced thrombin generation and slightly decreased fibrin clot density. COH with the GnRH-a reduced thrombin generation and improved fibrin clot features. This trial was registered (NCT04166825). Clinical Trial Registration Number: NCT04166825.

Intensive low-density lipoprotein cholesterol lowering improves fibrin clot properties: Association with lipoproteins and C-reactive protein

ObjectiveDense fibrin networks resistant to lysis characterize coronary artery disease (CAD) patients. We investigated whether a statin-induced decrease of low-density lipoprotein cholesterol (LDL-C) could improve fibrin clot phenotype in CAD patients. MethodsWe recruited 130 consecutive patients with advanced CAD (baseline LDL-C of 4.4 [IQR, 3.8–4.8] mmol/L), who on statins did not achieve the LDL-C goal based on the 2016 ESC/EAS guidelines. On standard statin treatment and after 6–12 months of high-dose statin treatment (atorvastatin 80 mg/day or rosuvastatin 40 mg/day), plasma fibrin clot permeability (Ks), clot lysis time (CLT), thrombin generation, coagulation and fibrinolytic factors were determined. ResultsAfter a median high-dose statin therapy of 7 months there was 25% reduction in LDL-C associated with increased Ks and shorter CLT, together with lower thrombin activatable fibrinolysis inhibitor, factor VIII, D-dimer, and C-reactive protein (CRP); thrombin generation was unaltered. The patients who achieved the therapeutic goal (n = 49, 37.7%) had 29.2% increase in Ks and 16.3% shorter CLT compared with the standard therapy, while there were no similar changes in the remaining patients. After adjustment for potential confounders, including CRP, an increase in Ks (by 1 × 10−9 cm2) and decrease in CLT (by 10 min) were independently predicted by on-treatment LDL-C goal (odds ratio [OR] 6.23, 95% confidence interval [CI] 1.97–20.33 and OR 3.11, 95% CI 1.05–8.99, respectively). ConclusionsFor the first time we showed that a decrease of LDL-C ≤ 1.8 mmol/L, or a reduction of at least 50% if the baseline LDL-C is between 1.8 and 3.5 mmol/L, is associated with favorable alterations to fibrin clot phenotype, with a stronger impact of lipoprotein reduction than CRP lowering, which might suggest that other potent cholesterol-lowering drugs can exert similar antithrombotic actions.

Markers of NET formation and stroke risk in patients with atrial fibrillation: association with a prothrombotic state

IntroductionNeutrophil extracellular traps (NETs) formation contributes to thrombosis but its role in atrial fibrillation (AF) is poorly explored. We investigated whether increased circulating NETs markers in relation to a hypercoagulable state can predispose to ischemic stroke in anticoagulated AF patients during long-term follow-up. Materials and methodsIn this cohort study 243 AF patients (median age 69 years) were assessed. Serum levels of citrullinated histone H3 (H3cit), myeloperoxidase (MPO), and peptidylarginine deiminase 4 (PAD4), along with plasma fibrin clot permeability (Ks), clot lysis time (CLT), endogenous thrombin potential (ETP), von Willebrand factor (VWF), and fibrinolysis proteins were measured. Stroke/transient ischemic attacks (TIA), major bleeding, and mortality were recorded during a median follow-up of 53 months while on anticoagulation. ResultsIschemic cerebrovascular events were observed in 20 patients (1.9%/year) who had at baseline higher H3cit, MPO, and PAD4 levels, all positively associated with CLT. Increased thrombin generation correlated positively with H3cit and PAD4, while Ks was inversely associated with H3cit levels. The independent predictors of ischemic stroke/TIA were H3cit (hazard ratio [HR] 9.48, 95% confidence interval [CI] 3.88–22.41, p < 0.0001) and VWF (HR 1.20, 95% CI 1.11–1.49, p = 0.001). Major bleeding (2.0%/year) and all-cause mortality (1.9%/year) were not related to NETs markers. ConclusionsEnhanced NETs formation related to prothrombotic markers is associated with increased risk of stroke/TIA in AF patients, suggesting a prognostic value of NETosis in AF.

Apolipoproteins and lipoprotein(a) as factors modulating fibrin clot properties in patients with severe aortic stenosis

Background and aimsLarge amounts of clot-bound lipoproteins were reported in proteomic analysis of plasma clot but their impact on fibrin clot properties is unknown. We investigated a contribution of lipid profile and apolipoproteins (apo) to the prothrombotic plasma fibrin clot phenotype in patients with aortic stenosis (AS). MethodsIn 138 patients with isolated severe AS, we determined serum apoA-I, A-II, B, C-II, C-III, E, oxidized low-density lipoprotein (OxLDL) and lipoprotein(a) concentrations. Plasma fibrin clot permeability (Ks), maximal absorbance (MaxAbsCLT2018 and MaxAbsLys50), and fibrinolytic capacity were studied using 3 plasma-based lysis assays (CLT2018, CLT, and Lys50), and compared with well-matched patients without AS (control group). ResultsAfter adjustment for confounding factors, including statin use, only low-density lipoprotein cholesterol (LDL-C) and apoB levels were inversely associated with Ks. Triglycerides, apoC-II, and C-III were associated with MaxAbsCLT2018 and MaxAbsLys50, explaining 56–64% of their variability. CLT2018 and CLT showed associations with total cholesterol, LDL-C, triglycerides, and OxLDL as well as with apoB, C-II, C-III, and E. ApoA-I, C-II, and C-III but not serum lipids were associated with Lys50. Only CLT2018 was associated with lipoprotein(a). ApoC-III, B, A-I, and E along with estimated glomerular filtration rate and OxLDL predicted hypofibrinolysis in multiple regression analysis. AS patients had higher lipoprotein(a) (+34.9%) and apoA-I (+25.9%) levels and less compact fibrin clots (−13.3% lower MaxAbsCLT2018, -53.2% lower MaxAbsLys50, and +28.3% higher Ks) displaying higher susceptibility to lysis (−17.9% lower Lys50) in comparison with control group. ConclusionsApolipoproteins and OxLDL contribute to prothrombotic fibrin clot phenotype in severe AS. Moreover, apolipoproteins better than serum lipids predicted hypofibrinolysis, which provides additional argument for a role of elevated lipoproteins in the prothrombotic state.

Fibrinogen β chain and FXIII polymorphisms affect fibrin clot properties in acute pulmonary embolism.

Prothrombotic fibrin clot properties, including increased clot density, are in part genetically determined. We investigated whether fibrinogen alpha-chain gene (FGA) c.991A>G (rs6050), fibrinogen beta chain gene (FGB) -455G>A (rs1800790) and factor XIII gene (F13) c.103G>T (rs5985) polymorphisms affect plasma fibrin clot properties in patients with acute pulmonary embolism (PE). As many as 126 normotensive patients with PE, free of cancer, were genotyped by TaqMan assay. Fibrin clot permeability (Ks ), clot lysis time (CLT) and endogenous thrombin potential (ETP) were assessed on admission. The minor allele frequencies were as follows: FGA rs6050 (n=62, 0.31), FGB rs1800790 (n=40, 0.17) and F13 rs5985 (n=49, 0.23). There were no differences related to any of the polymorphisms with regard to demographic, clinical and laboratory data, except for fibrinogen concentration, which was higher in carriers of F13 rs5985 polymorphism (p=.024), and PE combined with deep-vein thrombosis, which was less prevalent in FGB rs1800790 polymorphism carriers (p=.004). Carriers of FGB rs1800790 A allele and F13 rs5985T allele had lower Ks , prolonged CLT and higher ETP compared with major homozygotes (all p<.05). After adjustment for fibrinogen, all differences remained significant (all p<.01). There were no associations between the FGA rs6050 polymorphism and Ks , CLT or ETP. Our study showed that FGB rs1800790 and F13 rs5985 polymorphisms contribute to the prothrombotic fibrin clot phenotype and these effects are strong enough to be observed in the acute phase of PE.

Fibrin clot properties and fibrinolysis in patients with endocrine hypertension due to aldosterone or catecholamines excess.

The aim of the study was to investigate a new possible background of increased risk of cardiovascular events in two forms of endocrine hypertension: in primary aldosteronism (PA) and pheochromocytoma/paraganglioma (PPGL) in comparison to essential hypertension (EHT). Prothrombotic properties of the fibrin clot structure, impaired fibrinolysis and enhanced thrombin generation have been reported to be associated with increased cardiovascular risk. Patients with PA and PPGL were evaluated at baseline and re-evaluated 3 months after causative treatment. At baseline PA and PPGL patients were compared to matched EHT patients and to healthy controls. The study included 35 patients with PA, 16 patients with PPGL and two reference groups of patients with EHT (32 and 22 patients) and healthy controls (35 and 23 subjects). All subjects underwent evaluation according to the study protocol that included plasma fibrin clot permeability (Ks), clot lysis time, endogenous thrombin potential. There were no differences in clot structure and fibrinolytic activity in PA and PPGL patients as compared to matched patients with EHT, whereas all hypertensive groups were characterized by more compact fibrin clot structure, faster clot formation and enhanced thrombin generation in comparison to healthy controls. Both in PA and PPGL patients, fibrin clot properties and fibrinolytic parameters remained stable after the causative treatment. Patients with PA and PPGL are at a prothrombic state comparable to patients with EHT. The results suggest the higher risk of cardiovascular events observed in hypertensive PA and PPGL as compared to EHT is not mediated through investigated prothrombic mechanisms.

Thromboembolism and bleeding in patients with atrial fibrillation and stage 4 chronic kidney disease: impact of biomarkers.

Chronic kidney disease (CKD) is considered a risk factor for thromboembolic and bleeding events in patients with atrial fibrillation (AF). We sought to assess predictors of clinical outcomes among AF patients with advanced CKD. In a prospective cohort study, we enrolled 180 AF patients with stage 4 CKD, defined as estimated glomerular filtration rate of 15-29 ml/min/1.73 m2, on vitamin K antagonists (n = 90), and non-vitamin K antagonists oral anticoagulants (n = 90). We assessed biomarkers, including growth differentiation factor-15, cystatin C, and high-sensitivity cardiac troponin T, and prothrombotic state parameters, including plasma fibrin clot permeability (Ks). The median age of the patients was 71.0 (64.0-75.0) years (men 65.0%). The median estimated glomerular filtration rate was 24.0 (21.0-25.0) ml/min/1.73 m2 while the median CHA2DS2-VASc score was 3.0 (2.0-4.0). Age (hazard ratio [HR], 1.11; 95% confidence interval [CI], 1.02-1.20) and decreased Ks (HR, 0.55; 95% CI, 0.34-0.90) were associated with thromboembolic events (n = 18; 4.7% per year). Previous bleeding (HR, 3.21; 95% CI, 1.22-8.45), growth differentiation factor-15 (HR, 1.48; 95% CI, 1.29-1.69), cystatin C (HR, 9.24; 95% CI, 2.15-39.67), and high-sensitivity cardiac troponin T (HR, 1.30; 95% CI, 1.14-1.48) were independent predictors of major or clinically relevant non-major bleeding (n = 27; 7.1% per year). After adjustment for age and comorbidities, only cystatin C (HR, 3.95; 95% CI, 1.08-14.37) predicted mortality (n = 25; 6.5% per year). Novel biomarkers might be useful in risk stratification of thromboembolic and bleeding events in AF patients with stage 4 CKD receiving oral anticoagulants.

Patients scheduled for TAVI tend to form abnormal fibrin clots more resistant to lysis: the impact of age.

Fibrin accumulation within the stenotic leaflets associated with impaired fibrinolysis was observed in severe aortic stenosis (AS). Little is known about fibrin clot properties in patients scheduled for transcatheter aortic valve implantation (TAVI). We investigated whether TAVI patients display a more prothrombotic state, including suppressed fibrinolytic capacity compared to those undergoing surgery. We enrolled patients with advanced AS without significant atherosclerotic vascular disease scheduled for TAVI (n = 45) or surgical aortic valve replacement (SAVR, n = 59). Plasma fibrin clot features, including clot permeability (Ks) reflecting an average pore size, and lysis potential (Lys50), along with thrombin generation were determined off anticoagulation within 12 hours before the procedure. TAVI patients compared to SAVR had prolonged Lys50 (median 420 [IQR, interquartile range, 337-480] seconds vs 379 [337-428] seconds; P = 0.045) and formed denser clots, reflected by lower Ks (3.66 [3.05-4.84] vs 4.36 [3.6-5.27] × 10-9 cm2; P = 0.02), but after adjustment for age the latter difference was no longer significant. Apart from age, concomitant diabetes mellitus, or chronic kidney disease, prolonged Lys50 was an independent predictor of indication for TAVI in AS patients on multivariate regression analysis. There was a delayed start of thrombin generation in TAVI patients (lag time, 4.5 [3.8-6.3] minutes vs 4.2 [3.3-4.7] minutes; P = 0.035), without other differences in thrombin generation parameters. This study is the first to show that patients scheduled for TAVI are characterized by prothrombotic fibrin clot properties including denser fibrin meshwork and more resistant to lysis compared with those undergoing SAVR, which might explain in part increased thromboembolic risk following TAVI.

Certain Associations Between Iron Biomarkers and Total and γ' Fibrinogen and Plasma Clot Properties Are Mediated by Fibrinogen Genotypes.

Introduction: Evidence for the relationship between body iron and cardiovascular disease (CVD) is inconsistent and mechanisms involved remain poorly understood. Therefore, we first investigated whether there are linear or non-linear relationships between iron status and total and γ' fibrinogen as well as plasma fibrin clot properties and, second, determined whether there are interactions with iron biomarkers and fibrinogen and FXIII single nucleotide polymorphisms (SNPs) in relation to fibrinogen concentration and functionality.Methods: In this cross-sectional analysis of 2,010 apparently healthy Black South Africans we quantified total and γ' fibrinogen, serum iron, ferritin and transferrin using standardized methods and calculated transferrin saturation (TS). Clot architecture and lysis were explored with a global analytical turbidity assay. The SNPs were determined through an Illumina BeadXpress® platform.Results: Total, but not %γ', fibrinogen negatively correlated with serum iron concentrations, although both decreased over iron tertiles. %γ' fibrinogen correlated negatively with transferrin and decreased over the transferrin tertiles. A weak negative association between total fibrinogen and TS was detected with fibrinogen decreasing over the TS tertiles and categories based on TS. Lag time correlated positively with transferrin and increased over transferrin tertiles, when adjusting for fibrinogen. Before adjusting for fibrinogen, lag time was shorter in those with adequate iron status based on TS than other iron subcategories. Clot lysis time (CLT) negatively correlated with ferritin and was longer in the first than in the third ferritin tertile. Among iron status categories based on ferritin, only CLT differed and was longer in those with adequate iron than with iron-overload. CLT negatively correlated with TS, albeit weakly, shortened over the TS tertiles and was shorter in those with adequate iron based on TS categories. Interactions were observed between FGB SNPs and some of the markers of iron status investigated, in relation to the clot properties with the most prominent associations detected in homozygous carriers of the variant alleles for whom increased iron status was more beneficial than for those harboring the wild-type alleles. Iron modulated the influence of the SNPs so that for the majority iron was beneficial in respect of clot properties, but even more so for a minority group harboring specific variant alleles.Conclusion: This is the first large-scale epidemiological study to relate fibrinogen concentration and functionality to markers of iron status and to take genetic factors into consideration. We have detected a relationship between iron biomarkers and fibrinogen as well as clot characteristics that are influenced by the genetic make-up of an individual.

Fibrinolysis in Venous Thromboembolism

Fibrinolysis is of paramount importance in maintaining or regaining the patency of veins and pulmonary arteries obstructed by thrombi. Growing experimental and clinical evidence indicates that impaired fibrinolysis mediated by multiple complex mechanisms is involved in venous thromboembolism (VTE). Global plasma fibrin clot lysis markers, especially clot lysis time, have been reported to predict recurrent deep-vein thrombosis and pulmonary embolism. The current overview summarizes available data linking fibrinolysis to VTE and its long-term sequelae.

Fibrin clot properties among women with endometriosis and the impact of ovarian stimulation

Research questionIs there a difference in fibrin clot phenotype in women with endometriosis before and after ovarian stimulation? DesignProspective study including 73 infertile women in two age-matched groups: (i) with confirmed endometriosis (n = 29); (ii) without endometriosis (n = 44). Assessments of plasma fibrin clot permeability (Ks), efficiency of fibrinolysis using clot lysis time (CLT), along with thrombin generation (prothrombin fragments 1+2 [F1+2] and endogenous thrombin potential [ETP]) and fibrinolysis inhibitors were performed together with clinical pregnancy rate. ResultsEndometriosis was associated with increased thrombin generation, reflected by both higher F1+2 (+96.1%, P = 0.005) and ETP (+14.2%, P = 0.014) along with unfavourably altered fibrin clot properties represented by lower Ks (–31%, P < 0.001) and prolonged CLT (+13.5%, P = 0.02), compared with the non-endometriosis group. Moreover, women with endometriosis had higher plasminogen activator inhibitor-1 (PAI-1; +272%, P = 0.004) concentrations and alpha-2-antiplasmin activity (+39.9%, P < 0.001) in contrast to the other group. Ovarian stimulation led to reduction in F1+2 (–48.1%, P < 0.001), improvement of fibrin clot phenotype reflected by higher Ks (+25.9%, P < 0.001) and shortened CLT (–11.9%, P < 0.001), along with lower PAI-1 (–54%, P = 0.016) compared with the baseline in women with endometriosis. ConclusionsEndometriosis is associated with the prothrombotic fibrin clot phenotype and increased thrombin generation. Ovarian stimulation favourably alters fibrin clot properties and leads to comparable pregnancy outcomes to those in women without endometriosis.

Plasma fibrin clot properties and cardiovascular mortality in patients with type 2 diabetes: a long\u2010term follow\u2010up study

BackgroundPatients with type 2 diabetes mellitus (T2DM) are at high risk of cardiovascular mortality, but the mechanisms behind this remain unclear. Prothrombotic fibrin clot properties have been shown in T2DM and cardiovascular disease. We hypothesized that formation of denser clots, which are resistant to fibrinolysis, has a negative impact on cardiovascular mortality in T2DM.MethodsWe studied 133 T2DM patients aged 43–83 years. Plasma fibrin clot turbidity, permeation, compaction, and efficiency of clot lysis using 3 assays including the determination of maximum concentration (D-Dmax) and rate of increase in D-dimer concentration (D-Drate) released during tissue plasminogen activator-induced degradation, were evaluated at the time of enrollment, along with thrombin generation and fibrinolytic proteins. During a median follow-up period of 72 months, cardiovascular mortality was recorded.ResultsCardiovascular deaths (n = 16, 12%) occurred more frequently in patients with increased D-Dmax (> 4.26 mg/l, hazard ratio [HR] 5.43, 95% confidence interval [CI] 1.99–14.79), or decreased D-Drate (< 0.07 mg/l/min, HR 2.97, 95% CI 1.07–8.23), or increased peak thrombin (> 283.5 nM, HR 5.65, 95% CI 2.07–15.51). These predictors had an even more potent impact on cardiovascular mortality in patients with prior cardiovascular disease (64.7%) and with corresponding risks as follows: HR 6.18, 95% CI 2.02–18.96; HR 8.98, 95% CI 2.99–26.96; and HR 5.35, 95% CI 1.62–17.72, respectively. Other investigated fibrin variables and fibrinolytic proteins did not associate with cardiovascular mortality. In multivariable analysis, cardiovascular mortality was predicted by D-Dmax > 4.26 mg/l, age > 65 years, prior cardiovascular disease, and C-reactive protein > 3 mg/l.ConclusionsThis study is the first to show that formation of denser fibrin clots resistant to fibrinolysis could be a risk factor for long-term cardiovascular mortality in T2DM.

Factor XIII and Fibrin Clot Properties in Acute Venous Thromboembolism.

Coagulation factor XIII (FXIII) is converted by thrombin into its active form, FXIIIa, which crosslinks fibrin fibers, rendering clots more stable and resistant to degradation. FXIII affects fibrin clot structure and function leading to a more prothrombotic phenotype with denser networks, characterizing patients at risk of venous thromboembolism (VTE). Mechanisms regulating FXIII activation and its impact on fibrin structure in patients with acute VTE encompassing pulmonary embolism (PE) or deep vein thrombosis (DVT) are poorly elucidated. Reduced circulating FXIII levels in acute PE were reported over 20 years ago. Similar observations indicating decreased FXIII plasma activity and antigen levels have been made in acute PE and DVT with their subsequent increase after several weeks since the index event. Plasma fibrin clot proteome analysis confirms that clot-bound FXIII amounts associated with plasma FXIII activity are decreased in acute VTE. Reduced FXIII activity has been associated with impaired clot permeability and hypofibrinolysis in acute PE. The current review presents available studies on the role of FXIII in the modulation of fibrin clot properties during acute PE or DVT and following these events. Better understanding of FXIII’s involvement in the pathophysiology of acute VTE might help to improve current therapeutic strategies in patients with acute VTE.

Application of machine learning for predicting the outcome of treatment of patients with schizophrenia according to the indicators of «Thrombodynamics» test

To identify relationships between thrombodynamic values and the severity of the condition in patients with schizophrenia spectrum disorders (SSD) before and after treatment. The study included 92 patients in an acute state of schizophrenia or schizotypal disorder, aged 16 to 57 years (median age [Q1; Q3] - 25 years). All patients received complex psychopharmacotherapy adequate to their psychopathological state. The PANSS was used to assess the severity of symptoms in patients. The coagulation parameters were determined by the thrombodynamics test, in which the growth of fibrin clots in platelet free plasma are observed from special activator. The patient population was divided into two groups with weak and strong response to treatment. Data analysis included machine learning (ML) techniques: logistic regression, random forests, decision trees, support vector machines with radial basis functions, statistically weighted syndromes, permutation method. An analysis using permutation method revealed statistically significant different thrombodynamics values between groups of patients with weak and strong responses. There are significant differences between thrombodynamics values: T1D, T2D, T2Tlag and DTlag, and values characterizing the severity of positive symptoms before and after treatment (T1PposTot, T2PposTot), severity of psychopathological symptoms before treatment (T1Ppsy1, T1Ppsy6, T1Ppsy13). All ML techniques showed the relationship between thrombodynamics values and response to treatment. The best statistical significance was for statistically weighted syndromes method. The combination of the results of different ML techniques at a high level of statistical significance identifies the thrombodynamic predictors of weak effect of treatment of SSD.

Glycation and acetylation sites on fibrinogen in plasma fibrin clot of patients with type 2 diabetes: Effects of low-dose acetylsalicylic acid

Acetylsalicylic acid (ASA) and type 2 diabetes mellitus (T2DM) affect fibrin clot properties through fibrinogen acetylation or glycation. We aimed to identify glycation and acetylation sites on fibrinogen in plasma fibrin clot of T2DM patients with respect to effects of ASA and fibrin clot properties. In fibrin clots generated from plasma of 9 T2DM patients, we performed mass-spectrometric analysis of Nε-fructosyl-(FL), Nε-carboxyethyl-(CEL) and Nε-carboxymethyl-lysine (CML), and acetylation sites, before and after one-month administration of 75 mg/d ASA confirmed with determination of thromboxane B2 concentration (TXB2), along with clot permeability and lysis time, and thrombin generation.In the proteomic analysis, 216 proteins were identified. Among 10 glycation sites identified in α, 10 in β and 6 in γ fibrinogen chain, there were 17 FL, 5 CEL and 4 CML sites. Some of glycation sites in fibrinogen were previously reported to be involved in cross-linking by factor XIII (αK-208, αK-448 and αK-539) and plasmin cleavage (αK-81). There were 7 acetylation sites in α and β chains, and none in fibrinogen γ chain. Two acetylation sites were identical with FL sites (αK-195 and β-247), while one with CML site (βK-353). In 7 patients with low post-ASA TXB2, intensity of acetylation, as well as clot properties were unaffected by ASA. This study identifies glycation and acetylation sites on fibrinogen in plasma fibrin clot of T2DM and supports the view that low-dose ASA does not increase fibrinogen acetylation in T2DM. Our findings suggest that glycation may block sites previously identified to be acetylated in vitro.

Determinants of plasma fibrin clot lysis measured using three different assays in healthy subjects

IntroductionSeveral methods for measuring fibrinolytic capacity in plasma have been developed yielding frequently inconsistent results. We investigated which factors determine fibrinolytic capacity in three plasma-based assays. Material and methodsIn 80 apparently healthy controls (aged 43 ± 10 years, 50 women [62.5%]) we evaluated fibrinolysis using three assays: (1) by Pieters et al. (CLT2018), (2) by Lisman et al. (CLT), and (3) by Carter et al. (Lys50). Coagulation factors and fibrinolytic proteins, including histidine-rich glycoprotein (HRG) and γ′-fibrinogen, were determined. Regression models were performed to identify determinants of lysis times. ResultsPositive correlations were observed between CLT2018 and both CLT (r = 0.73) and Lys50 (r = 0.61), as well as between CLT and Lys50 (r = 0.46, all p < 0.001). The main determinants of both CLT2018 and CLT were plasminogen activator inhibitor-1 (PAI-1), followed by thrombin-activatable fibrinolysis inhibitor (TAFI) and α2-antiplasmin. Histidine-rich glycoprotein was a predictor of the longest-normal CLT2018 alone (OR 1.04, 95% CI 1.02–1.06). α2-Antiplasmin and fibrinogen levels, followed by PAI-1 and TAFI determined Lys50. After adjustment for age, sex, and body mass index, C-reactive protein (CRP) was an independent predictor of the top quartiles of the three lysis times. ConclusionsWe showed that apart from PAI-1, TAFI, and α2-antiplasmin, several other factors, in particular CRP, can affect the results of global fibrinolysis tests used in research. Our findings may help understand why the choice of a specific fibrinolysis assay can affect the presence and/or magnitude of intergroup differences in fibrinolytic capacity in a given disease state.