Tissue factor-bearing microparticles and CA19.9: two players in pancreatic cancer-associated thrombosis?

Background: Cancer-related venous thromboembolism (VTE) heralds a poor prognosis, especially in pancreatic adenocarcinoma (PAC). Tissue factor (TF) is implicated as one of the main culprits in PAC-associated VTE and disease progression.

Methods: In a prospective cohort study of 79 PAC patients, we measured plasma CA19-9 and microparticle-associated TF activity (MP-TF activity).

Fibrinogen γ' increases the sensitivity to activated protein C in normal and factor V Leiden plasma.

Activated protein C (APC) resistance, often associated with the factor V (FV) Leiden mutation, is the most common risk factor for venous thrombosis. We observed increased APC resistance in carriers of fibrinogen γ gene (FGG) haplotype 2, which is associated with reduced levels of the alternatively spliced fibrinogen γ' chain. This finding prompted us to study the effects of fibrinogen and its γ' chain on APC resistance.

Procoagulant tissue factor activity on microparticles is associated with disease severity and bacteremia in febrile urinary tract infections.

Introduction: Inhibition of tissue factor, the primary initiator of coagulation in sepsis, attenuates morbidity in primates infused with Escherichia coli. In a human endotoxemia model, microparticles expressing procoagulant TF (MP-TF) are released in blood concurrently with markers of inflammation and coagulation. We investigated whether the release of MP-TF into blood is accompanied by procoagulant and inflammatory changes in patients with E.

A novel serine protease secreted by medicinal maggots enhances plasminogen activator-induced fibrinolysis.

Maggots of the blowfly Lucilia sericata are used for the treatment of chronic wounds. As haemostatic processes play an important role in wound healing, this study focused on the effects of maggot secretions on coagulation and fibrinolysis. The results showed that maggot secretions enhance plasminogen activator-induced formation of plasmin and fibrinolysis in a dose- and time-dependent manner.

Cryo-electron microscopy of extracellular vesicles in fresh plasma.

Introduction: Extracellular vesicles (EV) are phospholipid bilayer-enclosed vesicles recognized as new mediators in intercellular communication and potential biomarkers of disease. They are found in many body fluids and mainly studied in fractions isolated from blood plasma in view of their potential in medicine. Due to the limitations of available analytical methods, morphological information on EV in fresh plasma is still rather limited.

Association of the thrombomodulin gene c.1418C>T polymorphism with thrombomodulin levels and with venous thrombosis risk.

Objective: To investigate the association of the THBD c.1418C>T polymorphism, which encodes for the replacement of Ala455 by Val in thrombomodulin (TM), with venous thromboembolism (VTE), plasma soluble TM, and activated protein C levels. In addition, human umbilical vein endothelial cells (HUVEC) isolated from 100 umbilical cords were used to analyze the relation between this polymorphism and THBD mRNA and TM protein expression.

Use of immuno-magnetic beads for direct capture of nanosized microparticles from plasma.

Increased microparticle tissue factor (TF) activity is not only found in cancer patients, but also in patients with cardiovascular and inflammatory diseases. Methods such as flow cytometry and impedance-based flow cytometry allow the analysis of microparticle subsets but provide no insight on which microparticles carry active TF. Conversely, the microparticle-TF activity itself does not reveal the cellular origin of the microparticles carrying the active TF.

Effects of oral anticoagulant therapy and haplotype 1 of the endothelial protein C receptor gene on activated protein C levels.

Oral anticoagulants (OACs) reduce activated protein C (APC) plasma levels less than those of protein C (PC) in lupus erythematosus and cardiac patients. Carriers of the H1 haplotype of the endothelial PC receptor gene (PROCR) have higher APC levels than non-carriers. We aimed to confirm these results in a large group of patients treated with OACs because of venous thromboembolism (VTE) and to assess whether the effect is influenced by the PROCR H1 haplotype.

Pre-analytical and analytical issues in the analysis of blood microparticles.

Results of plasma microparticles (MPs) measurements reported in the literature vary widely. This is clearly not only related to the lack of well-standardised MP assays, but also to variations in pre-analytical conditions. In this review we will discuss the pre-analytical variables related to plasma and MP preparation which may affect MP analysis.

Microparticle-associated tissue factor activity and venous thrombosis in multiple myeloma.

Multiple myeloma (MM) is associated with an increased risk of venous thromboembolic (VTE) complications. Aim of this study was to measure microparticle-associated tissue factor (MP-TF) activity in patients with newly diagnosed MM before and after chemotherapy and to investigate whether MP-TF activity is associated with VTE. MP-TF activity was assessed in 122 newly diagnosed MM patients who were eligible for combination chemotherapy.

Anti-plasminogen antibodies compromise fibrinolysis and associate with renal histology in ANCA-associated vasculitis.

Antibodies recognizing plasminogen, a key component of the fibrinolytic system, associate with venous thrombotic events in PR3-ANCA vasculitis. Here, we investigated the prevalence and function of anti-plasminogen antibodies in independent UK and Dutch cohorts of patients with ANCA-associated vasculitis (AAV). We screened Ig isolated from patients (AAV-IgG) and healthy controls by ELISA.

The R306G and R506Q mutations in coagulation Factor V reveals additional cleavage sites for Activated Protein C in the R313-R321 region and at R505.

The procoagulant function of activated factor V (FVa) is inhibited by activated Protein C (APC) through proteolytic cleavages at R306, R506 and R679. Recombinant FVa mutated at all three APC-cleavage sites, FVa-GQA, was still inactivated by APC through at least two cleavages in the heavy chain of FVa; relatively rapid cleavage at R(x1) close to residue 506 and slower cleavage at R(x2) nearby residue 306. We investigated the exact location of these two cleavages, by substitution of arginines by glutamine within the R(x1)-region (R501, R505 or R510) and the R(x2)-region (R313, R316, R317 or R321).

The role of procoagulants and anticoagulants in the development of venous thromboembolism.

Procoagulant and anticoagulant reactions play an important role in the regulation of thrombin formation during secondary hemostasis. Three phases can be recognized in the kinetics of thrombin formation: an initiation phase, a propagation phase and a termination phase. Dysregulation of thrombin formation during each of these phases by (hereditary) changes in the plasma concentration of pro- and anticoagulants contributes to the development of venous thrombosis.

Fibrinogen gamma gene 3'-end polymorphisms and risk of venous thromboembolism in the African-American and Caucasian population.

Genetic determinants of venous thromboembolism (VTE) in the African-American population are poorly characterised. It was recently shown that fibrinogen gamma gene (FGG) polymorphisms 10034C>T and 9340T>C influence VTE risk in the Caucasian population. In the African-American population these polymorphisms are common, with allele frequencies above 25%.

Endothelial protein C receptor polymorphisms and risk of myocardial infarction.

Background: Haplotypes A1 and A3 in the endothelial protein C receptor gene are tagged by the 4678G/C and 4600A/G polymorphisms, respectively, and have been reported to influence the risk of venous thromboembolism. We assessed whether these haplotypes modify the risk of premature myocardial infarction.

Design And Methods: We genotyped these polymorphisms in 689 patients with premature myocardial infarction and 697 control subjects.

Haplotypes of the interleukin-1 receptor antagonist gene, interleukin-1 receptor antagonist mRNA levels and the risk of myocardial infarction.

Background: The overall effect of the major pro-inflammatory cytokine interleukin-1 (IL-1) on coagulation and fibrinolysis is prothrombotic. We recently found that haplotype 5 (H5) of the gene (IL1RN) coding for the interleukin-1 receptor antagonist (IL-1Ra), the natural inhibitor of IL-1, is associated with an increased risk of venous thrombosis. It is unclear whether variations in IL1RN affect the risk of myocardial infarction.

Haplotypes of the EPCR gene, prothrombin levels, and the risk of venous thrombosis in carriers of the prothrombin G20210A mutation.

Background: Haplotypes A1 and A3 in the endothelial protein C receptor (EPCR) gene are tagged by 4678G/C and 4600A/G respectively. We assessed whether these haplotypes modify the risk of venous thromboembolism in carriers of the prothrombin 20210A allele.

Design And Methods: We genotyped 4678G/C and 4600A/G in 246 20210A carriers: 84 venous thromboembolism propositi and 162 relatives (13 symptomatic), and in 140 relatives not carrying the 20210A variant.

Maternal TLR4 and NOD2 gene variants, pro-inflammatory phenotype and susceptibility to early-onset preeclampsia and HELLP syndrome.

Background: Altered maternal inflammatory responses play a role in the development of preeclampsia and the hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome. We examined whether allelic variants of the innate immune receptors Toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain 2 (NOD2), that impair the inflammatory response to endotoxin, are related to preeclampsia and HELLP syndrome.

Methods And Findings: We determined five common mutations in TLR4 (D299G and T399I) and NOD2 (R702W, G908R and L1007fs) in 340 primiparous women with a history of early-onset preeclampsia, of whom 177 women developed HELLP syndrome and in 113 women with a history of only uneventful pregnancies as controls.

Fibrinogen gamma' in ischemic stroke: a case-control study.

Background And Purpose: To determine the contribution of fibrinogen gamma' levels and FGG haplotypes to ischemic stroke.

Methods: Associations between fibrinogen gamma' levels, fibrinogen gamma'/total fibrinogen ratio, and FGG haplotypes with the risk of ischemic stroke were determined in 124 cases and 125 controls.

Results: Fibrinogen gamma'/total fibrinogen ratio was higher in patients than in controls during the acute phase of the stroke and lower in the convalescent phase 3 months after the stroke.

Effect of oral contraceptives on thrombin generation measured via calibrated automated thrombography.

In a study population consisting of healthy men (n = 8), women not using oral contraceptives (OC) (n = 28) and women using different kinds of OC (n = 187) we used calibrated automated thrombography (CAT) in the absence and presence of added activated protein C (APC) to compare parameters that can be obtained from thrombin generation curves, i.e. lag time, time to peak, peak height and endogenous thrombin potential (ETP).