The role of ADAMTS-13 and von Willebrand factor in cancer patients: Results from the Vienna Cancer and Thrombosis Study

Prospects of liquid biopsy in the prognosis and clinical management of gastrointestinal cancers

Gastrointestinal (GI) cancers account for one-fourth of the global cancer incidence and are incriminated to cause one-third of cancer-related deaths. GI cancer includes esophageal, gastric, liver, pancreatic, and colorectal cancers, mostly diagnosed at advanced stages due to a lack of accurate markers for early stages. The invasiveness of diagnostic methods like colonoscopy for solid biopsy reduces patient compliance as it cannot be frequently used to screen patients. Therefore, minimally invasive approaches like liquid biopsy may be explored for screening and early identification of gastrointestinal cancers. Liquid biopsy involves the qualitative and quantitative determination of certain cancer-specific biomarkers in body fluids such as blood, serum, saliva, and urine to predict disease progression, therapeutic tolerance, toxicities, and recurrence by evaluating minimal residual disease and its correlation with other clinical features. In this review, we deliberate upon various tumor-specific cellular and molecular entities such as circulating tumor cells (CTCs), tumor-educated platelets (TEPs), circulating tumor DNA (ctDNA), cell-free DNA (cfDNA), exosomes, and exosome-derived biomolecules and cite recent advances pertaining to their use in predicting disease progression, therapy response, or risk of relapse. We also discuss the technical challenges associated with translating liquid biopsy into clinical settings for various clinical applications in gastrointestinal cancers.

Cellular Components Contributing to the Development of Venous Thrombosis in Patients with Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive type of cancer and has a poor prognosis. Patients with PDAC are at high risk of developing thromboembolic events, which is a leading cause of morbidity and mortality following cancer progression. Plasma-derived coagulation is the most studied process in cancer-associated thrombosis. Other blood components, such as platelets, red blood cells, and white blood cells, have been gaining less attention. This narrative review addresses the literature on the role of cellular components in the development of venous thromboembolism (VTE) in patients with PDAC. Blood cells seem to play an important role in the development of VTE. Altered blood cell counts, i.e., leukocytosis, thrombocytosis, and anemia, have been found to associate with VTE risk. Tumor-related activation of leukocytes leads to the release of tissue factor-expressing microvesicles and the formation of neutrophil extracellular traps, initiating coagulation and forming a scaffold for thrombi. Tissue factor-expressing microvesicles are also thought to be released by PDAC cells. PDAC cells have been shown to stimulate platelet activation and aggregation, proposedly via the secretion of podoplanin and mucins. Hypofibrinolysis, partially explained by increased plasminogen activator inhibitor-1 activity, is observed in PDAC. In short, PDAC-associated hypercoagulability is a complex and multifactorial process. A better understanding of cellular contributions to hypercoagulability might lead to the improvement of diagnostic tests to identify PDAC patients at highest risk of VTE.

Applications of Viscoelastic Testing in Breast Cancer Patients: A Systematic Review Focusing on Hypercoagulability and Free Flap Thrombosis

Viscoelastic testing is a clinically available method to assess hypercoagulability. This systematic review aims to provide a comprehensive overview of the existing literature and the potential use of such testing in patients with breast cancer. A systematic literature search for studies investigating the application of viscoelastic testing for patients with breast cancer was conducted. Studies were included as long as they were original, peer-reviewed, and in the English language. Studies were excluded if they were review articles, did not include breast cancer patients, or if the full text was unavailable. This review identified 10 articles that met the inclusion criteria. Two of the studies utilized rotational thromboelastometry, and an additional four studies used thromboelastography, to assess hypercoagulability in patients with breast cancer. Three of the identified articles discussed the use of thromboelastometry in free flap breast reconstruction for patients with breast cancer. One study was a retrospective chart review looking at thromboelastography and microsurgical breast reconstruction. Current literature regarding the application of viscoelastic testing in breast cancer and free flap breast reconstruction is limited, with no randomized trials thus far. However, some studies suggest that there may be potential utility in viscoelastic testing to assess risk for thromboembolism in breast cancer patients, and future research in this area is warranted.

Anticoagulant prescribing patterns in patients with primary central nervous system malignancies and secondary metastases

To evaluate the safety of direct oral anticoagulants (DOACs) versus low-molecular weight heparin (LMWH) in patients with central nervous system (CNS) malignancies and secondary metastases. All adult patients with CNS malignancies and secondary metastases who were treated with a DOAC or LMWH for any indication from 2018 to 2022 were included. The primary outcome was the incidence of any intracranial hemorrhage (ICH) after anticoagulation initiation. Secondary outcomes included non-ICH bleeding events and thromboembolic events. Tolerability was assessed by any changes in anticoagulant therapy during study period. 153 patients were included; 48 patients received enoxaparin and 105 received DOACs, of which apixaban was used most commonly. The population was predominantly White (74%) and male (59%) with a median age of 65. Data was censored for immortal time bias for outcomes evaluated beyond 3 months. ICH occurred in 7.7% of the population, more frequently in the enoxaparin group (DOACs 4, 4% vs. enoxaparin 7, 16%, p = 0.037). Non-ICH bleeds were predominantly minor and more common in the DOAC group (DOACs 13, 13% vs. enoxaparin 1, 2%, p = 0.037). Thromboembolic events were not different between groups (DOACs 9. 9% vs, enoxaparin 2, 4%, p = 0.503). Anticoagulant switches occurred more in the enoxaparin group (DOACs 12, 12.4% vs. enoxaparin, 37.8%, p < 0.001), primarily due to patient or provider preference. Our data supports DOACs to be preferred over LMWH for the treatment of VTE or for stroke prevention with AF to prevent ICH in patients with brain tumors or metastases.

ADAMTS-13: A Prognostic Biomarker for Portal Vein Thrombosis in Japanese Patients with Liver Cirrhosis

Portal vein thrombosis (PVT), one of the most prevalent hepatic vascular conditions in patients with liver cirrhosis (LC), is associated with high mortality rates. An imbalance between a disintegrin-like metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS-13) enzyme and von Willebrand factor (VWF) is responsible for hypercoagulability, including spontaneous thrombus formation in blood vessels. Herein, we aimed to identify potential prognostic and diagnostic biomarkers in Japanese patients with LC and PVT. In total, 345 patients were divided into two groups: 40 patients who developed PVT (PVT group) and 305 who did not develop PVT (NPVT group). Among the 345 patients with LC, 81% (279/345) were deemed ineligible due to the presence of preventive comorbidities, active or recent malignancies, and organ dysfunction. The remaining 66 patients were divided into two groups: the PVT group (n = 33) and the NPVT group (n = 33). Plasma ADAMTS-13 activity (ADAMTS-13:AC) and the vWF antigen (VWF:Ag) were measured using enzyme-linked immunosorbent assays. Contrast-enhanced, three-dimensional helical computed tomography (CT) was used to detect and characterize PVT. ADAMTS-13:AC was significantly lower in the PVT group than in the NPVT group. No significant differences in plasma vWF:Ag or liver stiffness were observed between the two groups. ADAMTS-13:AC of <18.8 was an independent risk factor for PVT on multivariate analyses (odds ratio: 1.67, 95% confidence interval: 1.21-3.00, p < 0.002). The receiver operating characteristic analysis of ADAMTS-13:AC revealed an area under the curve of 0.913 in PVT detection. Patients with PVT having ADAMTS-13:AC ≥18.8 (n = 17) had higher albumin levels and better prognoses than those with ADAMTS-13:AC <18.8 (n = 16). No significant correlations of ADAMTS-13:AC levels with either fibrin degradation product or D-dimer levels were observed. ADAMTS-13:AC levels could be potential diagnostic and prognostic biomarkers for PVT in Japanese patients with LC.

Crosstalk between Circulating Tumor Cells and Plasma Proteins-Impact on Coagulation and Anticoagulation

Cancer metastasis is a complex process. After their intravasation into the circulation, the cancer cells are exposed to a harsh environment of physical and biochemical hazards. Whether circulating tumor cells (CTCs) survive and escape from blood flow defines their ability to metastasize. CTCs sense their environment with surface-exposed receptors. The recognition of corresponding ligands, e.g., fibrinogen, by integrins can induce intracellular signaling processes driving CTCs' survival. Other receptors, such as tissue factor (TF), enable CTCs to induce coagulation. Cancer-associated thrombosis (CAT) is adversely connected to patients' outcome. However, cancer cells have also the ability to inhibit coagulation, e.g., through expressing thrombomodulin (TM) or heparan sulfate (HS), an activator of antithrombin (AT). To that extent, individual CTCs can interact with plasma proteins, and whether these interactions are connected to metastasis or clinical symptoms such as CAT is largely unknown. In the present review, we discuss the biological and clinical relevance of cancer-cell-expressed surface molecules and their interaction with plasma proteins. We aim to encourage future research to expand our knowledge of the CTC interactome, as this may not only yield new molecular markers improving liquid-biopsy-based diagnostics but also additional targets for better cancer therapies.

Prognostic value of von Willebrand factor levels in patients with metastatic melanoma treated by immune checkpoint inhibitors

BACKGROUND

An increased incidence of thrombotic complications associated with an increased mortality rate has been observed under immune checkpoint inhibition (ICI). Recent investigations on the coagulation pathways have highlighted the direct role of key coagulatory proteins and platelets in cancer initiation, angiogenesis and progression. The aim of this study was to evaluate the prognostic value of von Willebrand factor (vWF) and its regulatory enzyme a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), D-dimers and platelets in a cohort of patients with metastatic melanoma receiving ICI.

METHODS

In a prospective cohort of 83 patients with metastatic melanoma, we measured the systemic levels of vWF-antigen (vWF:Ag), ADAMTS13 activity, D-dimers and platelets, before the beginning of the treatment (baseline), and 6, 12 and 24 weeks after. In parallel, we collected standard biological parameters used in clinical routine to monitor melanoma response (lactate deshydrogenase (LDH), S100). The impact of neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) on overall survival (OS) in patients receiving ICI was assessed. Univariable and multivariable Cox proportional models were then used to investigate any potential association of these parameters to clinical progression (progression-free survival (PFS) and OS). Baseline values and variations over therapy course were compared between primary responders and resistant patients.

RESULTS

Patients with melanoma present with dysregulated levels of vWF:Ag, ADAMTS13 activity, D-dimers, LDH, S100 and CRP at the beginning of treatment. With a median clinical follow-up of 26 months, vWF:Ag interrogated as a continuous variable was significantly associated with PFS in univariate and multivariate analysis (HR=1.04; p=0.007). Lower values of vWF:Ag at baseline were observed in the primary responders group (median: 29.4 µg/mL vs 32.9 µg/mL; p=0.048) when compared with primary resistant patients. As for OS, we found an association with D-dimers and ADAMTS13 activity in univariate analysis and vWF:Ag in univariate and multivariate analysis including v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation and Eastern Cooperative Oncology Group (ECOG) performance status. Follow-up over the course of treatment depicts different evolution profiles for vWF:Ag between the primary response and resistance groups.

CONCLUSIONS

In this prospective cohort, coagulatory parameters such as ADAMTS13 activity and D-dimers are associated with OS but baseline vWF:Ag levels appeared as the only parameter associated with response and OS to ICI. This highlights a potential role of vWF as a biomarker to monitor ICI response of patients with malignant melanoma.

Impact of the von Willebrand factor-ADAMTS-13 axis on the risk of future venous thromboembolism

BACKGROUND

von Willebrand factor (VWF) and its cleaving protease, ADAMTS-13, form a pivotal axis that regulates hemostasis. However, the role of the VWF-ADAMTS-13 axis in the risk of future venous thromboembolism (VTE) is unknown.

OBJECTIVES

To investigate whether plasma ADAMTS-13 levels and an imbalance with VWF levels, assessed as the VWF/ADAMTS-13 ratio, are associated with the risk of future VTE.

PATIENTS/METHODS

A population-based nested case-control study, comprising 383 incident VTE cases and 780 age- and sex-matched controls, was derived from the Tromsø study cohort (1994-2007). Antigen levels of ADAMTS-13 and VWF were measured in plasma samples obtained at cohort baseline. Odds ratios (ORs) with 95% CIs were estimated according to quartile cutoffs of ADAMTS-13 and VWF/ADAMTS-13 ratio determined in controls.

RESULTS

In age- and sex-adjusted analysis, ADAMTS-13 levels were inversely associated with the VTE risk, with an OR of 1.40 (95% CI, 0.99-1.99) for the lowest vs highest quartiles. The VWF/ADAMTS-13 ratio was linearly associated with the VTE risk (P for trend = .001), with an OR of 1.70 (95% CI, 1.19-2.43) for the highest vs lowest quartiles, and the association was particularly pronounced for unprovoked VTE (OR, 2.81; 95% CI, 1.65-4.81). The ORs were only slightly attenuated after additional adjustments for body mass index and C-reactive protein.

CONCLUSIONS

Lowered ADAMTS-13 levels and an imbalance between ADAMTS-13 and VWF levels, reflected by an increased VWF/ADAMTS-13 ratio, were associated with an increased risk of future VTE. Our findings suggest that the VWF-ADAMTS-13 axis is involved in the pathogenesis of VTE.

Novel Classification of Thrombotic Disorders Based on Molecular Hemostasis and Thrombogenesis Producing Primary and Secondary Phenotypes of Thrombosis

Thrombosis, the common and deadliest disorder among human diseases, develops as a result of the intravascular hemostasis following an intravascular injury, which can be caused by a variety of trauma, non-traumatic insults or clinical illnesses. Thrombosis can occur at any location of the vascular system supplied by blood from the heart to large and smallest arterial and venous systems and may affect the function and anatomy of the organ and tissue. It more commonly occurs in the smaller circulatory system of the vascular tree such as arterioles and capillaries, and venules of the organs, especially in the brain, lungs, heart, pancreas, muscle and kidneys, and sinusoids of the liver. Thrombosis has been referred as the disease of "blood clots", which concept is incompletely defined, but represents many different hemostatic diseases from microthrombosis to fibrin clot disease, macrothrombosis, and combined micro-macrothrombosis. Thrombosis is produced following an intravascular injury via one or more combination of four different mechanisms of thrombogenesis: microthrombogenesis, fibrinogenesis, macrothrombogenesis and micro-macrothrombogenesis initiated by normal physiological hemostasis in vivo. The clinical phenotype expression of thrombosis is determined by: (1) depth of the intravascular wall injury, (2) extent of the injury affecting the vascular tree system, (3) physiological character of the involved vascular system, (4) locality of the vascular injury, and (5) underlying non-hemostatic conditions interacting with hemostasis. Recent acquisition of "two-path unifying theory" of hemostasis and "two-activation theory of the endothelium" has opened a new frontier in science of medicine by identifying the pathophysiological mechanism of different thrombotic disorders and also contributing to the better understanding of many poorly defined human diseases, including different phenotypes of stroke and cardiovascular disease, trauma, sepsis and septic shock, multiorgan dysfunction syndrome, and autoimmune disease, and others. Reviewed are the fundamentals in hemostasis, thrombogenesis and thrombosis based on hemostatic theories, and proposed is a novel classification of thrombotic disorders.

Breast cancer cells mediate endothelial cell activation, promoting von Willebrand factor release, tumor adhesion, and transendothelial migration

BACKGROUND

Breast cancer results in a three- to four-fold increased risk of venous thromboembolism (VTE), which is associated with reduced patient survival. Despite this, the mechanisms underpinning breast cancer-associated thrombosis remain poorly defined. Tumor cells can trigger endothelial cell (EC) activation resulting in increased von Willebrand factor (VWF) secretion. Importantly, elevated plasma VWF levels constitute an independent biomarker for VTE risk. Moreover, in a model of melanoma, treatment with low molecular weight heparin (LMWH) negatively regulated VWF secretion and attenuated tumor metastasis.

OBJECTIVE

To investigate the role of VWF in breast cancer metastasis and examine the effect of LMWH in modulating EC activation and breast tumor transmigration.

METHODS

von Willebrand factor levels were measured by ELISA. Primary ECs were used to assess tumor-induced activation, angiogenesis, tumor adhesion, and transendothelial migration.

RESULTS AND CONCLUSION

Patients with metastatic breast cancer have markedly elevated plasma VWF:Ag levels that also correlate with poorer survival. MDA-MB-231 and MCF-7 breast cancer cells induce secretion of VWF, angiopoietin-2, and osteoprotegerin from ECs, which is further enhanced by the presence of platelets. Vascular endothelial growth factor-A (VEGF-A) plays an important role in modulating breast cancer-induced VWF release. Moreover, VEGF-A from breast tumor cells also contributes to a pro-angiogenic effect on ECs. VWF multimers secreted from ECs, in response to tumor-VEGF-A, mediate adhesion of breast tumor cells along the endothelium. LMWH inhibits VWF-breast tumor adhesion and transendothelial migration. Our findings highlight the significant crosstalk between tumor cells and the endothelium including increased VWF secretion which may contribute to tumor metastasis.

ADAMTS13 protease or lack of von Willebrand factor protects irradiation and melanoma-induced thrombotic microangiopathy in zebrafish

BACKGROUND

Severe deficiency of plasma ADAMTS13 activity may result in potentially fatal thrombotic thrombocytopenic purpura and relative deficiency of plasma ADAMTS13 activity may be associated with adverse outcomes of certain malignancies. Here, we report the role of ADAMTS13 or lack of von Willebrand factor (VWF) in reducing irradiation and melanoma-induced thrombotic microangiopathy (TMA) and mortality in zebrafish.

METHODS

Zebrafish melanoma cell line (ZMEL) was injected subcutaneously into wild-type (wt), adamts13-/- (a13-/- ), von Willebrand factor (vwf-/- ), and a13-/- vwf-/- zebrafish following total body irradiation; the tumor growth, its gene expression pattern, the resulting thrombocytopenia, and the mortality were determined.

RESULTS

Total body irradiation at 30 Gy alone resulted in a transient thrombocytopenia in both wt and a13-/- zebrafish. However, thrombocytopenia occurred earlier and more profound in a13-/- than in wt zebrafish, which was resolved 2 weeks following irradiation alone. An inoculation of ZMEL following the irradiation resulted in more severe and persistent thrombocytopenia, as well as earlier death in a13-/- than in wt zebrafish. The vwf-/- or a13-/- vwf-/- zebrafish were protected from developing severe thrombocytopenia following the same maneuvers. RNA-sequencing revealed significant differentially expressed genes associated with oxidation-reduction, metabolism, lipid, fatty acid and cholesterol metabolic processes, steroid synthesis, and phospholipid efflux in the melanoma explanted from a13-/- zebrafish compared with that from the wt controls.

CONCLUSIONS

Our results indicated that plasma ADAMTS13 or lack of VWF may offer a significant protection against the development of irradiation- and/or melanoma-induced TMA. Such a microenvironment may directly affect melanoma cell phenotypes via alternation in the oxidation-reduction and lipid metabolic pathways.

The role of VWF/FVIII in thrombosis and cancer progression in multiple myeloma and other hematological malignancies

Cancer associated thrombosis (CAT) is associated with significant morbidity and mortality, highlighting an unmet clinical need to improve understanding of the pathophysiology of CAT. Multiple myeloma (MM) is associated with one of the highest rates of thrombosis despite widespread use of thromboprophylactic agents. The pathophysiology of thrombosis in MM is multifactorial and patients with MM appear to display a hypercoagulable phenotype with potential contributory factors including raised von Willebrand factor (VWF) levels, activated protein C resistance, impaired fibrinolysis, and abnormal thrombin generation. In addition, the toxic effect of anti-myeloma therapies on the endothelium and contribution to thrombosis has been widely described. Elevated VWF/factor VIII (FVIII) plasma levels have been reported in heterogeneous cohorts of patients with MM and other hematological malignancies. In specific studies, high plasma VWF levels have been shown to associate with VTE risk and reduced overall survival. While the mechanisms underpinning this remain unclear, dysregulation of the VWF and A Disintegrin And Metalloprotease Thrombospondin type 1, motif 13 (ADAMTS-13) axis is evident in certain solid organ malignancies and correlates with advanced disease and thrombosis. Furthermore, thrombotic microangiopathic conditions arising from deficiencies in ADAMTS-13 and thus an accumulation of prothrombotic VWF multimers have been reported in patients with MM, particularly in association with specific myeloma therapies. This review will discuss current evidence on the pathophysiological mechanisms underpinning thrombosis in MM and in particular summarize the role of VWF/FVIII in hematological malignancies with a focus on thrombotic risk and emerging evidence for contribution to disease progression.

Heparan sulfate dependent binding of plasmatic von Willebrand factor to blood circulating melanoma cells attenuates metastasis

Heparan sulfate (HS), a highly negatively charged glycosaminoglycan, is ubiquitously present in all tissues and also exposed on the surface of mammalian cells. A plethora of molecules such as growth factors, cytokines or coagulation factors bear HS binding sites. Accordingly, HS controls the communication of cells with their environment and therefore numerous physiological and pathophysiological processes such as cell adhesion, migration, and cancer cell metastasis. In the present work, we found that HS exposed by blood circulating melanoma cells recruited considerable amounts of plasmatic von Willebrand factor (vWF) to the cellular surface. Analyses assisted by super-resolution microscopy indicated that HS and vWF formed a tight molecular complex. Enzymatic removal of HS or genetic engineering of the HS biosynthesis showed that a reduced length of the HS chains or complete lack of HS was associated with significantly reduced vWF encapsulation. In microfluidic experiments, mimicking a tumor-activated vascular system, we found that vWF-HS complexes prevented vascular adhesion. In line with this, single molecular force spectroscopy suggested that the vWF-HS complex promoted the repulsion of circulating cancer cells from the blood vessel wall to counteract metastasis. Experiments in wild type and vWF knockout mice confirmed that the HS-vWF complex at the melanoma cell surface attenuated hematogenous metastasis, whereas melanoma cells lacking HS evade the anti-metastatic recognition by vWF. Analysis of tissue samples obtained from melanoma patients validated that metastatic melanoma cells produce less HS. Transcriptome data further suggest that attenuated expression of HS-related genes correlate with metastases and reduced patients' survival. In conclusion, we showed that HS-mediated binding of plasmatic vWF to the cellular surface can reduce the hematogenous spread of melanoma. Cancer cells with low HS levels evade vWF recognition and are thus prone to form metastases. Therefore, therapeutic expansion of the cancer cell exposed HS may prevent tumor progression.

ABO blood group type and risk of venous thromboembolism in patients with cancer

Venous thromboembolism (VTE) is common in patients with cancer. Although in the general population blood type non-O is associated with increased VTE risk, the impact of ABO blood type on risk of cancer-associated VTE has not been clarified. To determine the influence of ABO blood type on cancer-associated VTE risk, we conducted an analysis within the Vienna Cancer and Thrombosis Study, a prospective cohort study including patients with newly diagnosed or recurrent cancer observed for the primary outcome VTE. Restricted cubic spline analysis was performed and specific time-restricted subdistribution hazard ratios (SHR) were calculated to investigate the association between non-O blood type and VTE over time. One thousand, seven hundred and eight patients were included in the analysis (median follow-up time: 24 months; interquartile range: 10-24), and 151 patients developed VTE (8.8%). During the first 3 months of follow-up, there was no association between non-O blood type and VTE risk (SHR: 1.00; 95% confidence interval [CI]: 0.60-1.67). Thereafter, non-O blood type was associated with a higher VTE risk (SHR: 1.79; 95% CI: 1.12-2.85). Furthermore, non-O blood type was associated with increased VTE risk in patients with intermediate and low thrombotic risk tumor types (SHR: 1.73; 95% CI: 1.09-2.73) but not in very high-risk types (pancreatic, gastroesophageal, and brain cancer; SHR: 0.94; 95% CI: 0.55-1.61). This association was weakened after adjustment for factor VIII. Non-O blood type is a time-dependent predictor of VTE in patients with cancer. It is associated with increased VTE risk beyond 3 months of follow-up and in patients with intermediate- and low-risk tumor types.

The Intriguing Connections between von Willebrand Factor, ADAMTS13 and Cancer

von Willebrand factor (VWF) is a complex and large protein that is cleaved by ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13), and together they serve important roles in normal hemostasis. Malignancy can result in both a deficiency or excess of VWF, leading to aberrant hemostasis with either increased bleeding or thrombotic complications, as respectively seen with acquired von Willebrand syndrome and cancer-associated venous thromboembolism. There is emerging evidence to suggest VWF also plays a role in inflammation, angiogenesis and tumor biology, and it is likely that VWF promotes tumor metastasis. High VWF levels have been documented in a number of malignancies and in some cases correlate with more advanced disease and poor prognosis. Tumor cells can induce endothelial cells to release VWF and certain tumor cells have the capacity for de novo expression of VWF, leading to a proinflammatory microenvironment that is likely conducive to tumor progression, metastasis and micro-thrombosis. VWF can facilitate tumor cell adhesion to endothelial cells and aids with the recruitment of platelets into the tumor microenvironment, where tumor/platelet aggregates are able to form and facilitate hematogenous spread of cancer. As ADAMTS13 moderates VWF level and activity, it too is potentially involved in the pathophysiology of these events. VWF and ADAMTS13 have been explored as tumor biomarkers for the detection and prognostication of certain malignancies; however, the results are underdeveloped and so currently not utilized for clinical use. Further studies addressing the basic science mechanisms and real word epidemiology are required to better appreciate the intriguing connections between VWF, ADAMTS13 and malignancy. A better understanding of the role VWF and ADAMTS13 play in the promotion and inhibition of cancer and its metastasis will help direct further translational studies to aid with the development of novel cancer prognostic tools and treatment modalities.

Reduced ADAMTS13 Activity in Correlation with Pathophysiology, Severity, and Outcome of COVID-19: A Retrospective Observational Study

BACKGROUND

Low ADAMTS13 activity has been suggested to be an interplaying factor in the pathogenesis of COVID-19, considering that it is a thromboinflammatory disease with high risk of microthrombosis.

OBJECTIVES

The study aimed to explore the correlation between ADAMTS13 activity and the pathophysiological pathway of COVID-19.

METHODS

We carried out a retrospective observational study of 87 patients with COVID-19 in NMC Royal Hospital, Abu Dhabi, UAE. ADAMTS13 activity was measured and compared with patients' characteristics and clinical outcomes.

RESULTS

Low ADAMTS13 activity was associated with pneumonia (p = 0.007), severity of COVID-19 (p <0.001), and mechanical ventilation rates (p = 0.018). Death was more frequently observed among patients (5 patients) with low ADAMTS13 activity compared with normal activity (1 patient), as well as inflammatory markers. Decreased ADAMTS13 activity increased with the risk of pneumonia, severity of COVID-19, need for mechanical ventilation, and use of anticoagulants ([OR = 4.75, 95% CI 1.54-18.02, p = 0.011], [OR = 6.50, 95% CI 2.57-17.74; p <0.001], [OR = 4.10, 95% CI 1.29-15.82; p = 0.024], [OR = 8.00, 95% CI 3.13-22.16; p <0.001], respectively). The low ADAMTS13 activity group had a slightly longer time to viral clearance than the normal ADAMTS13 activity group, but it was not statistically significant (20 days, 95% CI 16-27 days vs 17 days, 95% CI 13-22 days; p = 0.08; Log rank = 3.1).

CONCLUSIONS

Low ADAMTS13 activity has been linked to pneumonia, COVID-19 severity, use of anticoagulants, and need for mechanical ventilation but not to mortality. We propose rADAMTS13 as a novel treatment for severe COVID-19.

Role of von Willebrand factor in venous thromboembolic disease

Objective

Evolving evidence of the shared risk factors and pathogenic mechanisms in arterial and venous thrombosis questions of the strict vascular dichotomy of arterial vs venous. The connection between arterial and venous thrombosis has been highlighted by common underlying inflammatory processes, a concept known as thromboinflammatory disease. Using this relationship, we can apply knowledge from arterial disease to better understand and potentially mitigate venous disease. A protein that has been extensively studied in atherothrombotic disease and inflammation is von Willebrand factor (VWF). Because many predisposing and provoking factors of venous thromboembolism (VTE) have been shown to directly modulate VWF levels, it is, perhaps, not surprising that VWF has been highlighted by several recent association studies of patients with VTE.

Methods

In the present narrative review, we investigated more deeply the effects of VWF in venous disease by synthesizing the data from clinical studies of deep vein thrombosis of the limbs, pulmonary embolism, portal and cerebral vein thrombosis, and the complications of thrombosis, including post-thrombotic syndrome, venous insufficiency, and chronic thromboembolic pulmonary hypertension. We have also discussed the findings from preclinical studies to highlight novel VWF biochemistry in thrombosis and therapeutics.

Results

Across the spectrum of venous thromboembolic disease, we consistently observed that elevated VWF levels conferred an increased risk of VTE and long-term venous complications. We have highlighted important findings from VWF molecular research and have proposed mechanisms by which VWF participates in venous disease. Emerging evidence from preclinical studies might reveal novel targets for thromboinflammatory disease, including specific VWF pathophysiology. Furthermore, we have highlighted the utility of measuring VWF to prognosticate and risk stratify for VTE and its complications.

Conclusions

As the prevalence of inflammatory processes, such as aging, obesity, and diabetes increases in our population, it is critical to understand the evolving role of VWF in venous disease to guide clinical decisions and therapeutics.

Involvement of platelet-derived VWF in metastatic growth of melanoma in the brain

Background

The prognosis of patients with brain metastases (BM) is poor despite advances in our understanding of the underlying pathophysiology. The high incidence of thrombotic complications defines tumor progression and the high mortality rate. We, therefore, postulated that von Willebrand factor (VWF) promotes BM via its ability to induce platelet aggregation and thrombosis.

Methods

We measured the abundance of VWF in the blood and intravascular platelet aggregates of patients with BM, and determined the specific contribution of endothelial and platelet-derived VWF using in vitro models and microfluidics. The relevance for the brain metastatic cascade in vivo was demonstrated in ret transgenic mice, which spontaneously develop BM, and by the intracardiac injection of melanoma cells.

Results

Higher levels of plasma VWF in patients with BM were associated with enhanced intraluminal VWF fiber formation and platelet aggregation in the metastatic tissue and peritumoral regions. Platelet activation triggered the formation of VWF multimers, promoting platelet aggregation and activation, in turn enhancing tumor invasiveness. The absence of VWF in platelets, or the blocking of platelet activation, abolished platelet aggregation, and reduced tumor cell transmigration. Anticoagulation and platelet inhibition consistently reduced the number of BM in preclinical animal models.

Conclusions

Our data indicate that platelet-derived VWF is involved in cerebral clot formation and in metastatic growth of melanoma in the brain. Targeting platelet activation with low-molecular-weight heparins represents a promising therapeutic approach to prevent melanoma BM.

Pancreatic Cancer and Platelets Crosstalk: A Potential Biomarker and Target

Platelets have been recognized as key players in hemostasis, thrombosis, and cancer. Preclinical and clinical researches evidenced that tumorigenesis and metastasis can be promoted by platelets through a wide variety of crosstalk between cancer cells and platelets. Pancreatic cancer is a devastating disease with high morbidity and mortality worldwide. Although the relationship between pancreatic cancer and platelets in clinical diagnosis is described, the interplay between pancreatic cancer and platelets, the underlying pathological mechanism and pathways remain a matter of intensive study. This review summaries recent researches in connections between platelets and pancreatic cancer. The existing data showed different underlying mechanisms were involved in their complex crosstalk. Typically, pancreatic tumor accelerates platelet aggregation which forms thrombosis. Furthermore, extracellular vesicles released by platelets promote communication in a neoplastic microenvironment and illustrate how these interactions drive disease progression. We also discuss the advantages of novel model organoids in pancreatic cancer research. A more in-depth understanding of tumor and platelets crosstalk which is based on organoids and translational therapies may provide potential diagnostic and therapeutic strategies for pancreatic cancer progression.

Pre-surgical level of von Willebrand factor as an evident indicator of breast cancer recurrence

BACKGROUND

Endothelial and platelet activation as well as a disruption of haemostatic balance are crucial in cancer-dependent venous thromboembolism development.

OBJECTIVE

The aim of this study was to investigate the influence of von Willebrand factor (VWF), sE-selectin, sP-selectin as well as VWF/sE-selectin and sP-selectin/sE-selectin ratios on the probability of disease relapse in invasive breast carcinoma (IBrC) cases.

METHODS

Eighty-four patients with IA-IIB stage of IBrC who passed a comprehensive clinicopathologic evaluation were included in the study. Follow-up was completed in all patients with a 15.48 % recurrence rate. An immunoassay of VWF antigen, sE-selectin, sP-selectin, as well as an immunohistochemistry of oestrogen and progesterone receptors, human epidermal growth factor receptor 2 (HER2) and Ki67 was performed in all cases.

RESULTS

The VWF/sE-selectin ratio was significantly higher in patients with poorly differentiated tumours than in those with high-differentiated tumours. A positive correlation between VWF concentration and tumour grade was noted. Eleven of 13 events happened in patients with VWF value below 600 mU/mL with recurrence rate of 25%, but only two events occurred in subject with VWF values above the 600 mU/mL (5%; P= 0.0028).

CONCLUSIONS

Our study show that VWF could be considered as a suitable biomarker of breast cancer relapse.

Risk Factors and Prediction Models for Venous Thromboembolism in Ambulatory Patients with Lung Cancer

Venous thromboembolism (VTE) is a significant cause of mortality in patients with lung cancer. Despite the availability of a wide range of anticoagulants to help prevent thrombosis, thromboprophylaxis in ambulatory patients is a challenge due to its associated risk of haemorrhage. As a result, anticoagulation is only recommended in patients with a relatively high risk of VTE. Efforts have been made to develop predictive models for VTE risk assessment in cancer patients, but the availability of a reliable predictive model for ambulate patients with lung cancer is unclear. We have analysed the latest information on this topic, with a focus on the lung cancer-related risk factors for VTE, and risk prediction models developed and validated in this group of patients. The existing risk models, such as the Khorana score, the PROTECHT score and the CONKO score, have shown poor performance in external validations, failing to identify many high-risk individuals. Some of the newly developed and updated models may be promising, but their further validation is needed.

Overview of risk assessment models for venous thromboembolism in ambulatory patients with cancer

A B S T R A C T Important progress has been made in the development of risk assessment models (RAM) for the identification of outpatients on anticancer treatment at risk of venous thromboembolism (VTE). Since the breakthrough publication of the original Khorana risk score (KRS) more than 10 years ago, a new generation of KRS-based scores have been developed, including the Vienna Cancer and Thrombosis Study, PROTECHT, CONKO, ONCOTEV, TicOnco and the CATS/MICA score. Among these the CATS/MICA score showed that a simplified score composed of only two calibrated predictors, the type of cancer and the D-dimer levels, offers a user-friendly tool for the evaluation of cancer-associated thrombosis (CAT) risk. The COMPASS-CAT score is the first that introduced a more synthetic approach of risk evaluation by combining cancer-related predictors with patient comorbidity in a score which is designed for the types of cancer frequently seen in the community (i.e. breast, lung colon or ovarian cancers) and has been externally validated in independent studies. The Throly score is registered as part of the same group as it has a similar structure to the COMPASS-CAT score and is applicable in patients with lymphoma. The incorporation of specific biomarkers of hypercoagulability to the RAM for CAT offers the possibility to perform a precision medicine approach in the prevention of CAT. The improvement of RAM for CAT with artificial intelligence methodologies and deep learning techniques is the challenge in the near future.

Von Willebrand Factor, Factor VIII, and Other Acute Phase Reactants as Biomarkers of Inflammation and Endothelial Dysfunction in Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGvHD) is an immune mediated late complication of allogeneic hematopoietic stem cell transplantation (alloHSCT). Discovery of adequate biomarkers could identify high-risk patients and provide an effective pre-emptive intervention or early modification of therapeutic strategy, thus reducing prevalence and severity of the disease among long-term survivors of alloHSCT. Inflammation, endothelial injury, and endothelial dysfunction are involved in cGvHD development. Altered levels of acute phase reactants have shown a strong correlation with the activity of several immune mediated disorders and are routinely used in clinical practice. Since elevated von Willebrand factor (VWF) and factor VIII (FVIII) levels have been described as acute phase reactants that may indicate endothelial dysfunction and inflammation in different settings, including chronic autoimmune diseases, they could serve as potential candidate biomarkers of cGvHD. In this review we focused on reported data regarding VWF and FVIII as well as other markers of inflammation and endothelial dysfunction, evaluating their potential role in cGvHD.

Quantification of von Willebrand factor and ADAMTS-13 after traumatic injury: a pilot study

BACKGROUND

Von Willebrand factor (VWF) is an acute phase reactant synthesized in the megakaryocytes and endothelial cells. VWF forms ultra-large multimers (ULVWF) which are cleaved by the metalloprotease ADAMTS-13, preventing spontaneous VWF-platelet interaction. After trauma, ULVWF is released into circulation as part of the acute phase reaction. We hypothesized that trauma patients would have increased levels of VWF and decreased levels of ADAMTS-13 and that these patients would have accelerated thrombin generation.

METHODS

We assessed plasma concentrations of VWF antigen and ADAMTS-13 antigen, the Rapid Enzyme Assays for Autoimmune Diseases (REAADS) activity of VWF, which measure exposure of the platelet-binding A1 domain, and thrombin generation kinetics in 50 samples from 30 trauma patients and an additional 21 samples from volunteers. Samples were analyzed at 0 to 2 hours and at 6 hours from the time of injury. Data are presented as median (IQR) and Kruskal-Wallis test was performed between trauma patients and volunteers at both time points.

RESULTS

REAADS activity was greater in trauma patients than volunteers both at 0 to 2 hours (190.0 (132.0-264.0) vs. 92.0 (71.0-114.0), p<0.002) and at 6 hours (167.5 (108.0-312.5.0) vs. 92.0 (71.0-114.0), p<0.001). ADAMTS-13 antigen levels were also decreased in trauma patients both at 0 to 2 hours (0.84 (0.51-0.94) vs. 1.00 (0.89-1.09), p=0.010) and at 6 hours (0.653 (0.531-0.821) vs. 1.00 (0.89-1.09), p<0.001). Trauma patients had accelerated thrombin generation kinetics, with greater peak height and shorter time to peak than healthy volunteers at both time points.

DISCUSSION

Trauma patients have increased exposure of the VWF A1 domain and decreased levels of ADAMTS-13 compared with healthy volunteers. This suggests that the VWF burst after trauma may exceed the proteolytic capacity of ADAMTS-13, allowing circulating ULVWF multimers to bind platelets, potentially contributing to trauma-induced coagulopathy.

LEVEL OF EVIDENCE

Prospective case cohort study.

Von Willebrand factor:antigen and ADAMTS-13 level, but not soluble P-selectin, are risk factors for the first asymptomatic deep vein thrombosis in cancer patients undergoing chemotherapy

Background

There is a high incidence of deep vein thrombosis (DVT) among cancer patients undergoing chemotherapy. Chemotherapy-induced vascular endothelial cell activation (VECA) is characterized by increased plasma levels of von Willebrand factor (vWF) and soluble P-selectin (sP-selectin), leading to the activation of endothelial cells and signaling cascades. The biological role of a disintegrin-like and metalloproteinase with thrombospondin type 1 motif, member 13 (ADAMTS-13) is to control the activity of vWF and consequently the risk of thrombosis. The objective of this study was to investigate the roles of sP-selectin, vWF, and ADAMTS-13 as risk factors for the first episode of DVT in cancer patients undergoing chemotherapy.

Methods

This prospective cohort study was conducted at Dr. Kariadi Hospital, Indonesia, on 40 cancer patients. Prechemotherapy (baseline) and postchemotherapy sP-selectin, vWF antigen (vWF:Ag), and ADAMTS-13 plasma levels were determined with ELISAs before and 3 months after chemotherapy. The clinical characteristics of the patients, cancer type, cancer stage, chemotherapy regimen, ABO blood type, D-dimer level and Khorana risk score were also analyzed using logistic regression. Patients were observed for the possibility of developing DVT during chemotherapy.

Results

DVT was confirmed in 5 patients (12.5%) after a period of 3 months. In patients with DVT, sP-selectin and vWF were significantly higher while ADAMTS-13 was lower than in their counterparts. The levels of baseline vWF:Ag and ADAMTS-13, with cut-off points ≥ 2.35 IU/mL and ≤ 1.03 IU/mL, respectively, were found to independently predict the incidence of DVT. In the multivariate logistic regression analysis, the relative risk (RR) for DVT in patients with high vWF:Ag was 3.80 (95% CI 1.15–12.48, p = 0.028), and that for patients with low ADAMTS-13 was 2.67 (95% CI 1.22–23.82, p = 0.005). The vWF:Ag/ADAMTS-13 ratio and both vWF:Ag and ADAMTS-13 dynamics during treatment were also able to differentiate those with prospective DVT. However, sP-selectin and other covariates showed no statistical significance.

Conclusion

We found that prechemotherapy plasma levels of vWF:Ag ≥ 2.35 IU/mL and ADAMTS-13 ≤ 1.03 IU/mL are independent risk factors for DVT incidence among cancer patients.

Von Willebrand factor and cancer; metastasis and coagulopathies

Von Willebrand factor (VWF) is a multimeric procoagulant plasma glycoprotein that mediates platelet adhesion along the endothelium. In addition to its role maintaining normal hemostasis, more recently novel biological functions for VWF have been described, including inflammation, angiogenesis, and metastasis. Significantly increased plasma VWF levels have been reported across a variety of cancer patient cohorts. Given that VWF is established as a risk factor for venous thrombosis, this is of direct clinical importance. Moreover, elevated VWF has also been observed localized within the tumor microenvironment, correlating with advanced disease stage and poorer clinical outcome. Critically, evidence suggests that elevated VWF levels in cancer patients may not only contribute to cancer associated coagulopathies but may also mediate cancer progression and metastasis. Studies have shown that VWF can promote pro-inflammatory signaling, regulate angiogenesis and vascular permeability, which may facilitate tumor cell growth and extravasation across the vessel wall. Endothelial secreted VWF multimers contribute to the adhesion and transendothelial migration of tumor cells key for tumor dissemination. In support of this, VWF inhibition attenuated metastasis in vivo. Perhaps most intriguingly, specific tumor cells have been reported to acquire de novo VWF expression which increases tumor-platelet heteroaggregates and confers enhanced metastatic activity. Current knowledge on the roles of VWF in cancer and in particular its contribution to metastasis and cancer associated coagulopathies is summarized in this review.

Von Willebrand Factor and ADAMTS13 and long-term outcomes in patients undergoing percutaneous coronary intervention

BACKGROUND

Von Willebrand factor (VWF) and its cleaving protease a disintegrin-like and metalloprotease with thrombospondin type I repeats 13 (ADAMTS13) are pivotal mediators of thrombosis and are associated with the progression of atherosclerosis. We investigated the impact of VWF, ADAMTS13 and VWF/ADAMTS13 on long-term major adverse cardiovascular outcomes (MACE) in patients undergoing percutaneous coronary intervention (PCI).

METHODS

We analysed 701 patients undergoing PCI between 2003 and 2006. VWF and ADAMTS13 antigen levels were measured before PCI. As primary endpoint, we investigated MACE, a composite of all-cause mortality, myocardial infarction or ischemic stroke during 8 years of follow-up. As secondary endpoint, we investigated all-cause mortality.

RESULTS

Mean age was 63.8 years, 496 (70.8%) were male. Acute coronary syndrome (ACS) was diagnosed in 347 (49.5%) patients, stable coronary artery disease (SCAD) in 354 (50.5%). During follow-up 228 (32.5%) patients experienced MACE, and 161 (23.0%) died. In ACS patients, VWF was significantly associated with MACE (HR 1.402 (95%CI 1.003-1.959), p = 0.048), whereas ADAMTS13 and VWF/ADAMTS13 had no predictive value. In SCAD, neither VWF, ADAMTS13, nor VWF/ADAMTS13 correlated with MACE. VWF was significantly associated with all-cause death in ACS patients (HR 1.841 (95%CI 1.187-2.856), p = 0.006), but not in SCAD (1.394 (95%CI 0.856-2.269), p = 0.181). ADAMTS13 and VWF/ADAMTS13 were not correlated with ACS and SCAD, respectively.

CONCLUSION

VWF but not ADAMTS13 and VWF/ADAMTS13 was associated with MACE and mortality in patients with ACS but not SCAD. This finding highlights the importance of VWF as an essential marker of risk in patients with ACS.