Role of von Willebrand factor in venous thromboembolic disease

LC-MS/MS-Profiling of Human Serum Unveils Significant Increase in Neuroinflammation and Carcinogenesis Following Chronic Organophosphate Exposure

The utilization of organophosphate pesticides (OPs) has escalated in response to the growing global food demand driven by a rapidly increasing population and the environmental disruptions caused by climate change. While acute exposure leads to cholinergic poisoning, chronic OP exposure has been linked to organ dysfunction, inflammation, and carcinogenesis. Serum samples from healthy individuals (n = 11), patients with acute OP exposure (n = 12), and those with chronic OP exposure (n = 31) were analyzed to discern the differentially expressed pathways after acute and chronic OP exposure. Differential expression analysis identified 132 proteins altered in chronic exposure vs control, 86 in acute exposure vs control, and 124 in chronic vs acute exposure. Pathway analysis revealed increased blood coagulation and reduced LXR/RXR activation and DCHR24 signaling in both acute and chronic exposures. Elevated levels of pro-inflammatory proteins, such as S100A8, VWF, and GPIBA, were observed, particularly in chronic exposure, highlighting significant inflammatory effects of OP exposure. These findings provide insights into the pathological mechanisms underlying chronic OP exposure and its contribution to inflammation and long-term health risks.

Effect of plasma levels of factor VIII according to procoagulant phospholipids on the risk of future venous thromboembolism

Background

A high level of plasma coagulation factor (F)VIII is an established and likely causal risk factor for venous thromboembolism (VTE). Procoagulant phospholipids (PPLs) facilitate FVIII activity in coagulation.

Objectives

To assess the association between plasma levels of FVIII and risk of future VTE according to PPL clotting time (PPLCT), an inverse surrogate measure of plasma PPL activity.

Methods

A population-based nested case-control study comprising 278 incident VTE cases and 593 randomly selected age- and sex-matched controls were derived from the Tromsø cohort. Exposures were determined from data collected at the cohort baseline. Logistic regression was used to estimate odds ratios (ORs) with 95% CIs for VTE across tertiles of FVIII and PPLCT.

Results

High (tertile 3) vs low (tertile 1) FVIII antigen levels resulted in an age- and sex-adjusted OR of 1.53 (95% CI, 0.78-3.00) in those with high PPLCT (low PPL activity), while the corresponding OR for those with low PPLCT (high PPL activity) was 1.88 (95% CI, 0.96-3.66). In the biological interaction analysis, participants with both high FVIII and PPL activity had an OR of 1.86 (95% CI, 0.97-3.57) compared with those with low FVIII and PPL activity. In the joint exposure group, 10% (95% CI, -55% to 75%) of VTEs could be attributable to the interaction between FVIII and PPL activity. Results remained similar after further adjustment for body mass index, C-reactive protein, arterial cardiovascular disease, and cancer.

Conclusion

The effect of high FVIII levels on VTE risk was particularly augmented in those with high PPL activity, suggesting that the effect of FVIII on VTE risk might be partially dependent on PPL activity.

The Prevalence of the Thrombotic SNPs rs6025, rs1799963, rs2066865, rs2289252 and rs8176719 in Patients with Venous Thromboembolism in the Czech Population

IntroductionStudy aimed to determine the occurrence of 5 thrombosis-related single-nucleotide polymorphisms (SNPs) in patients with venous thromboembolism (VTE) (n = 2630) and a control group (n = 2637) in the Czech population.MethodsThe following gene SNPs were detected in both groups: F5 Leiden (rs6025), F2 (rs1799963), FGG, fibrinogen gamma' (rs2066865), F11 (rs2289252) and ABO (rs8176719). Statistical analysis was performed using SAS statistical software with population genetics tools.ResultsHeterozygotes for F5 Leiden were associated with a 5.58-fold and homozygotes F5 Leiden with a 33.46-fold increased risk of VTE. At SNP rs1799963 (F2, prothrombin), only heterozygotes had a significant 3.9-fold increased risk of VTE. The findings at SNP rs2066865 (fibrinogen gamma', FGG) showed a 1.37-fold increased risk of VTE for FGG heterozygotes and a 1.77-fold increased risk of VTE for FGG homozygotes. There is also a significant 1.42-fold increase risk of VTE in the heterozygotes and a 1.80-fold increase risk of VTE in the homozygotes of the SNP rs 2289252 (F11). Further higher increases in the risk of VTE in both variants were found in patients with VTE at rs8176719 (ABO, non-O). It corresponds to a 2.2-fold increase in the risk of VTE in heterozygotes and a 3.5-fold increase in the risk of VTE in homozygotes.ConclusionBesides F5 Leiden and prothrombin mutation, the study suggests that the gene polymorphisms of FGG (rs2066865), F11 (rs2289252) and ABO (rs8176719) play a role as an independent heritable risk factor for VTE in the Czech population.

Comparative Analysis of Coagulation Activation in Rheumatoid Arthritis Patients Treated With TNF Inhibitors Versus JAK Inhibitors: A Longitudinal Study

OBJECTIVES

This study aims to investigate the activation of the coagulation system of RA patients and assess changes during anti-inflammatory treatment with tumor necrosis factor blockers (anti-TNF) and Janus kinase inhibitors (JAKi).

METHODS

Biomarkers for the coagulation system, including D-dimer, fibrinogen, prothrombin time, activated partial thrombin time, prothrombin fragment 1 + 2, thrombin-antithrombin complex (TAT), activated factor IX, antithrombin complex, and von Willebrand factor (vWF), were longitudinally measured in 83 RA patients treated with anti-TNF and 38 RA patients with JAKi. Data were collected at baseline, after 1, 3, and 6 months.

RESULTS

The mean age was 57 (±14) years; 76% was female. The mean DAS28-CRP was 3.6 (±1.3) for anti-TNF users and 4.1 (±1.4) for JAKi users at baseline and declined in both groups. Baseline coagulation markers levels were comparable between groups. In anti-TNF users, D-dimer and fibrinogen levels significantly declined (-0.31 mg/L, p = 0.01 and -0.71 g/L, p < 0.001, respectively), whereas TAT significantly increased after 6 months follow-up (1.46 μg/L, p = 0.03) and no effect on vWF ( p = 0.98). In JAKi users, vWF declined significantly during the 6 months follow-up (-37.41%, p < 0.001); additionally, there were reductions of D-dimer, fibrinogen, and TAT that did not reach significance (-0.17 mg/L, p = 0.59; -0.49 g/L, p = 0.12; and 0.68 μg/L, p = 0.27, respectively).

CONCLUSIONS

The prothrombotic tendency in active RA declined during effective treatment with both anti-TNF and JAKi. Altogether, the biomarkers used in this study suggest that an increased VTE risk in the first 6 months due to either treatment with anti-TNF or JAKi is unlikely.

ROTEM and von Willebrand Factor in COVID patients presenting with acute ischemic stroke: A case series: ROTEM and von Willebrand Factor in COVID-19 Related Stroke

OBJECTIVES

SARS-CoV-2 (COVID) induces systemic thrombotic complications including acute ischemic stroke. In this case series, we report markers of inflammation, coagulation factors including von Willebrand factor antigen, and rotational thromboelastometry (ROTEM) data.

MATERIALS AND METHODS

Retrospective case series of COVID patients seen at a single comprehensive stroke center between 2020-2022. For patients undergoing mechanical thrombectomy (MT), ROTEM data was collected during the procedure and analyzed on ROTEM delta system.

RESULTS

Fifteen patients (33.3% female) median age 65-years-old presented with COVID and acute ischemic stroke. Thirteen had LVO. The mean NIHSS was 15 (range 0-35) on admission and 18 (0-42) at discharge. Most were cryptogenic (N=7, 46.7%), followed by cardioembolic (N=6, 40%) and large artery-to-artery embolization (N=2, 13.3%). mRS was < 3 in 8 (53%) patients at discharge. None of the patients were on anticoagulation, and five were on antiplatelet therapy pre-hospitalization. Seven received thrombolytics with alteplase (tPA), and 10 had MT. Baseline platelet count was 102 K/uL (range 102-291 K/uL). vWF was measured in 12 patients, all elevated, with seven having levels >400 (180%). ROTEM data was collected in six patients. Three who received tPA had abnormal EXTEM and FIBTEM data (CT extem > 85secs, A10 EXTEM < 45mm, and A10 FIBTEM < 10mm). Notably, INTEM (CT INTEM >208secs) was abnormal in five of the six patients, two of whom did not receive tPA.

CONCLUSIONS

Elevated vWF antigen levels with abnormal ROTEM data suggests that COVID induces changes in the clotting cascade. More robust research is needed to investigate these findings. Thrombolytics, MT, and antiplatelet agents should be utilized to treat COVID-related ischemic stroke based on current clinical guidelines.

Novel Deep Sea Isoindole Alkaloid FGFC1 Exhibits Its Fibrinolytic Effects by Inhibiting Thrombin-Activatable Fibrinolysis Inhibitor

BACKGROUND

The thrombin-activatable fibrinolysis inhibitor (TAFI) is an important regulator in the balance between blood clot formation (coagulation) and dissolution (fibrinolysis), which is mainly activated by thrombin bonded with thrombomodulin (TM).

METHODS

In this study, the investigation focused on the unique target TAFI of fungi fibrinolytic compound 1 (FGFC1), a novel fibrinolytic compound sourced from the deep sea. In this sense, the regulation of TAFI by FGFC1, in comparison to established TAFI inhibitors such as DS-1040 and PCTI in hPPP, was investigated, which was validated through the molecular docking of FGFC1 to TAFI. The inhibitory effect of FGFC1 on TAFI-mediating coagulation (ex vivo and in vitro) and its fibrinolytic effect (ex vivo) were investigated in hPPP and hCMEC/D3 cells, respectively, followed by SEM.

RESULTS

FGFC1 solutions ranging from 0.023 to 0.736 mM effectively inhibited TAFI activation. Notably, the 0.023 mM concentration demonstrated significant suppression, comparable to DS-1040 and PCTI. These inhibitory effects of FGFC1 (0.023-0.368 mM) were further validated through the enhancement in TAFI (TAFIa) activation by fibrins in the coagulum prior to proteolysis, resulting in the cleavage of TAFIa from 33 kDa to 28 kDa. Furthermore, these regulatory effects of FGFC1 on TAFI were demonstrated to have minimal association with TM-mediated control, as confirmed through a molecular docking analysis. FGFC1 (0.023-0.092 mM) was suggested to have obstructive effects on TAFI-mediated coagulation in the hPPP, which was demonstrated by the inhibition of clot aggregation, protein crystallization, and platelet anchoring, as observed through SEM. Simultaneously, FGFC1 (0.023 to 0.368 mM) significantly enhanced TAFI-mediated fibrinolysis, which was also supported by increased levels of t-PA, u-PA, and plasmin.

CONCLUSIONS

From the above findings, FGFC1 is identified as a novel dual-target bioactive compound participating in blood formation/dissolution that demonstrates anti-coagulation and fibrinolytic effects by regulating TAFI activation, inhibiting TAFIa-fibrin combination, and initiating proteolysis. It also provided convincing evidence that TAFI plays a critical role in thrombolysis as a molecular link between coagulation and fibrinolysis. Furthermore, the application of FGFC1 was indicated as a potential therapeutic strategy in thromboembolic and hemorrhagic diseases.

Novel functions for von Willebrand factor

ABSTRACT

For many years, it has been known that von Willebrand factor (VWF) interacts with factor VIII, collagen, and platelets. In addition, the key roles played by VWF in regulating normal hemostasis have been well defined. However, accumulating recent evidence has shown that VWF can interact with a diverse array of other novel ligands. To date, over 60 different binding partners have been described, with interactions mapped to specific VWF domains in some cases. Although the biological significance of these VWF-binding interactions has not been fully elucidated, recent studies have identified some of these novel ligands as regulators of various aspects of VWF biology, including biosynthesis, proteolysis, and clearance. Conversely, VWF binding has been shown to directly affect the functional properties for some of its ligands. In keeping with those observations, exciting new roles for VWF in regulating a series of nonhemostatic biological functions have also emerged. These include inflammation, wound healing, angiogenesis, and bone metabolism. Finally, recent evidence supports the hypothesis that the nonhemostatic functions of VWF directly contribute to pathogenic mechanisms in a variety of diverse diseases including sepsis, malaria, sickle cell disease, and liver disease. In this manuscript, we review the accumulating data regarding novel ligand interactions for VWF and critically assess how these interactions may affect cellular biology. In addition, we consider the evidence that nonhemostatic VWF functions may contribute to the pathogenesis of human diseases beyond thrombosis and bleeding.

The impact of von Willebrand factor on fibrin formation and structure unveiled with type 3 von Willebrand disease plasma

Normally, von Willebrand factor (VWF) remains inactive unless its A1A2 domains undergo a shear stress-triggered conformational change. We demonstrated the capacity of a recombinant A2 domain of VWF to bind and to affect fibrin formation, altering the fibrin clot structure. The data indicated that VWF contains an additional binding site for fibrin in the A2 domain that plays a role in the incorporation of VWF to the polymerizing fibrin. This study is to examine the hypothesis that active plasma VWF directly influence fibrin polymerization and the structure of fibrin clots. The study used healthy and type 3 von Willebrand disease (VWD) plasma, purified plasma VWF, fibrin polymerization assays, confocal microscopy and scanning electron microscopy. The exposed A2 domain in active VWF harbors additional binding sites for fibrinogen, and significantly potentiates fibrin formation (P < 0.02). Antibody against the A2 domain of VWF significantly decreased the initial rate of change of fibrin formation (P < 0.002). Clot analyses revealed a significant difference in porosity between normal and type 3 VWD plasma (P < 0.008), further supported by scanning electron microscopy, which demonstrated thicker fibrin fibers in the presence of plasma VWF (P < 0.0003). Confocal immunofluorescence microscopy showed punctate VWF staining along fibrin fibrils, providing visual evidence of the integration of plasma VWF into the fibrin matrix. The study with type 3 VWD plasma supports the hypothesis that plasma VWF directly influences fibrin polymerization and clot structure. In addition, a conformational change in the A1A2 domains exposes a hidden fibrin(ogen) binding site, indicating that plasma VWF determines the fibrin clot structure.

Determination of vWF, ADAMTS-13 and Thrombospondin-1 in Venous Thromboembolism and Relating Them to the Presence of Factor V Leiden Mutation

Thrombophilia in venous thromboembolism (VTE) is multifactorial. Von Willebrand factor (vWF) plays a major role in primary hemostasis. While elevated vWF levels are well documented in VTE, findings related to its cleaving protease (ADAMTS-13) are contradicting. The aim of this study was to determine vWF, ADAMTS-13, and the multifactorial Thrombospondin-1 (TSP-1) protein levels in patients after 3-6 months following an unprovoked VTE episode. We also explored a possible association with factor V Leiden (FVL) mutation. vWF, ADAMTS-13 and TSP-1 were analyzed using ELISA kits in 60 VTE patients and 60 controls. Patients had higher levels of vWF antigen (P = .021), vWF collagen-binding activity (P = .008), and TSP-1 protein (P < .001) compared to controls. ADAMTS-13 antigen was lower in patients (P = .046) compared to controls but ADAMTS-13 activity was comparable between the two groups (P = .172). TSP-1 showed positive correlation with vWF antigen (rho = 0.303, P = .021) and negative correlation with ADAMTS-13 activity (rho = -0.244, P = .033) and ADAMTS-13 activity/vWF antigen ratio (rho = -0.348, P = .007). A significant association was found between the presence of FVL mutation and VTE (odds ratio (OR): 9.672 (95% confidence interval (CI) 2.074-45.091- P = .004), but no association was found between the mutation and the studied proteins (P > .05). There appears to be an imbalance between vWF and ADAMTS-13 in VTE patients even after 3-6 months following the onset of VTE. We report that the odds of developing VTE in carriers of FVL mutation are 9.672 times those without the mutation, but the presence of this mutation is not associated with the studied proteins.

Biomarkers and the post-thrombotic syndrome: A systematic review of biomarkers associated with the occurrence of the post-thrombotic syndrome after lower extremity deep venous thrombosis

INTRODUCTION

Post-thrombotic syndrome (PTS) is a frequent chronic complication of deep venous thrombosis (DVT). Biomarkers are potentially valuable clinical tools for handling PTS. The purpose of this review was to examine which biomarkers are associated with the development of PTS in adults with lower extremity DVT.

METHODS

We performed a systematic review of all English language prospective studies of biomarkers and PTS published in PubMed and EMBASE. Studies were included if diagnosing DVT by diagnostic imaging and assessing PTS by clinical scales, for example, the Villalta scale. Biomarkers of thrombophilia and pathological clot properties were not assessed. Data was reported qualitatively.

RESULTS

15 prospective studies were included. Studies varied widely in study design and methods of data analysis. Forty-six different biomarkers were examined, with seven being measured in two or more studies. The most frequently studied biomarkers were D-dimer, CRP, and IL-6. Associations between PTS and D-dimer were predominantly significant, while results on CRP and IL-6 were inconsistent. ICAM-1 was consistently associated with PTS in all studies and at all timepoints. IL-10 was significantly related to PTS development in the largest study and at all time points. Adiponectin, tPA, HRG and TAFI, MMP-1 and -8, and TIMP-1 and -2 were significantly associated with PTS in single studies.

CONCLUSION

(1) Further research on biomarkers and PTS is clearly warranted. (2) Significant differences in study designs made it difficult to draw reliable conclusions regarding individual biomarkers. We suggest the implementation of a standardized framework for the study of biomarkers and PTS, to make comparison of future studies more feasible. (3) D-dimer, ICAM-1, IL-10, MMP-1 and 8, TIMP-1, TIMP-2, and adiponectin are clinical biomarkers of particular interest to include in future studies of PTS. Large scale systemic quantitative proteomic analyses of DVT patients could help identify novel biomarkers of interest in PTS-patients.

John A, Ling M, Le J, Harris J, Rhoads N, Wang Y, Fu X, Chen J, Fazio S, Lindner JR, López JA. Low-density lipoprotein promotes microvascular thrombosis by enhancing von Willebrand factor self-association

von Willebrand factor (VWF) mediates primary hemostasis and thrombosis in response to hydrodynamic forces. We previously showed that high shear promoted self-association of VWF into hyperadhesive strands, which can be attenuated by high-density lipoprotein (HDL) and apolipoprotein A-I. In this study, we show that low-density lipoprotein (LDL) binds VWF under shear and enhances self-association. Vortexing VWF in tubes resulted in its loss from the solution and deposition onto tube surfaces, which was prevented by HDL. At a stabilizing HDL concentration of 1.2 mg/mL, increasing concentrations of LDL progressively increased VWF loss, the effect correlating with the LDL-to-HDL ratio and not the absolute concentration of the lipoproteins. Similarly, HDL diminished deposition of VWF in a post-in-channel microfluidic device, whereas LDL increased both the rate and extent of strand deposition, with both purified VWF and plasma. Hypercholesterolemic human plasma also displayed accelerated VWF accumulation in the microfluidic device. The initial rate of accumulation correlated linearly with the LDL-to-HDL ratio. In Adamts13-/- and Adamts13-/-LDLR-/- mice, high LDL levels enhanced VWF and platelet adhesion to the myocardial microvasculature, reducing cardiac perfusion, impairing systolic function, and producing early signs of cardiomyopathy. In wild-type mice, high plasma LDL concentrations also increased the size and persistence of VWF-platelet thrombi in ionophore-treated mesenteric microvessels, exceeding the accumulation seen in similarly treated ADAMTS13-deficient mice that did not receive LDL infusion. We propose that targeting the interaction of VWF with itself and with LDL may improve the course of thrombotic microangiopathies, atherosclerosis, and other disorders with defective microvascular circulation.

Predictive value of von Willebrand factor for venous thrombosis in patients with chronic heart failure complicated with atrial fibrillation after anticoagulant therapy

BACKGROUND

We investigated the value of von Willebrand factor (vWF) in predicting venous thrombosis in patients with chronic heart failure complicated with atrial fibrillation after anticoagulation therapy.

METHODS

Totally, 126 patients with chronic heart failure complicated with atrial fibrillation who were treated with anticoagulant therapy and 60 healthy individuals were enrolled. One year after anticoagulant therapy, venous thrombosis occurred in 19 patients. Clinical data of patients were collected. The plasma vWF activity was detected and compared. The logistic regression analysis was used to analyze the influencing factors of vWF. ROC curve was used to evaluate the predictive value of plasma vWF.

RESULTS

Plasma vWF activity was significantly higher in patients with heart failure and atrial fibrillation than control subjects (P < 0.01). The vWF activity in patients with venous thrombosis was significantly higher than that in patients without venous thrombosis (P < 0.01). ROC curve analysis showed that the cut-off value of vWF activity for venous thrombosis within one year after anticoagulant therapy was 267.5%, and the AUC was 0.742 (95% CI: 0.764-0.921, P < 0.05). The sensitivity was 80.0%, and the specificity was 63.6%. Factors of diabetes, myocardial ischemia, old myocardial infarction, and lower extremity atherosclerosis, but not sex, age, coronary heart disease, hypertension, and cardiac function, had significant effect on vWF activity (P < 0.05). Logistic regression analysis showed that vWF activity was significantly related with atherosclerosis of lower limbs and old myocardial infarction, but not significantly related with diabetes and myocardial ischemia. The risk of venous thrombosis in patients with vWF activity greater than 267.5% was 10.667 times higher than that in patients with vWF activity less than 267.5% (P < 0.05).

CONCLUSION

The vWF activity greater than 267.5% has clinical predictive value for the risk of lower extremity venous thrombosis in patients with chronic heart failure complicated with atrial fibrillation within 1 year of anticoagulant therapy.

Peri-operative thrombophilia in patients undergoing liver resection for colorectal metastases

BACKGROUND

Routine chemical venous thromboembolism (VTE) prophylaxis for liver surgery remains controversial, and often delayed post-operatively due to perceived bleeding risk. This study asked whether patients undergoing hepatectomy for colorectal metastases (CRM) were at risk from VTE pre-operatively, and the impact of hepatectomy on that risk.

METHODS

Single-centre prospective observational cohort study of patients undergoing open hepatectomy for CRM, comparing pre-, peri- and post-operative haemostatic variables.

RESULTS

Of 336 hepatectomies performed October 2017-December 2019, 60 resections in 57 patients were recruited. There were 28 (46.7%) major resections, with median (interquartile range [IQR]) blood loss 150.0 (76.3-263.7) mls, no blood transfusions, post-operative VTE events or deaths. Patients were prothrombotic pre-operatively (high median factor VIIIC and increased thrombin generation velocity index), an effect exacerbated post-hepatectomy. Major hepatectomies had a significantly greater median drop in Protein C, rise in Factor VIIIC and von Willebrand Factor, versus minor resections (p = 0.001, 0.005, 0.001 respectively). Patients with parenchymal transection times greater than median (40 min), had significantly increased median (IQR) PMBC-TFmRNA expression [1.65(0.93-2.70)2ddCt], versus quicker transections [0.99(0.69-1.28)2ddCt, p = 0.020].

CONCLUSIONS

Patients with CRM are prothrombotic pre-operatively, an effect exacerbated by hepatectomy, particularly longer, complex resections, suggesting chemical thromboprophylaxis be considered early in the patient pathway.

The Association between Platelet Glycocalicin and High Microsatellite Instability in Colorectal Cancer

Background. Elevated platelet volume is the risk factor for the development and poor overall survival of colorectal cancer (CRC) patients. Both microsatellite status and platelet glycoprotein Ibα (GPIbα) are related to platelet volume in CRC patients. This study aimed to investigate platelet GPIbα ectodomain (termed glycocalicin) levels among CRC patients and the association between the glycocalicin levels and microsatellite status in CRC. Methods. The clinical and laboratory data of 430 CRC patients between January 2018 and December 2018 in Harbin Medical University Cancer Hospital were collected. The microsatellite status was determined with a polymerase chain reaction. The participants were separated into high microsatellite instability (MSI-H) and microsatellite stable (MSS) groups according to microsatellite status. The glycocalicin levels were measured with an enzyme-linked immunosorbent assay, and the cut-off point was determined with the receiver-operating characteristics curve. The clinical and pathological characteristics were collected via electronic medical records. Logistic regression was used to explore the association between glycocalicin and microsatellite status. Results. Among the 430 CRC patients enrolled, 64 patients (14.9%) were identified as MSI-H and others as MSS CRC. Glycocalicin levels were significantly reduced in patients with MSI-H than those with MSS. After controlling for potential confounders, logistic regression analysis revealed that glycocalicin levels were independently associated with MSI-H CRC. Conclusions. Reduced glycocalicin levels are associated with the MSI-H subtype of CRC. Further research is needed to elucidate the mechanisms of the association between glycocalicin and MSI-H in CRC patients.