Receptors for extracellular nucleotides are the focus of increasing attention for their ability to cause release of plasma membrane vesicles (microparticles, MPs). Here, we show that monocyte-derived human dendritic cells (DCs) stimulated with a P2X 7 receptor (P2X 7 R) agonist undergo a large release of MPs endowed with procoagulant activity. Functional and Western blot studies revealed that MPs contain the membrane-bound form of tissue factor (TF), a glycoprotein acting as essential cofactor of activated factor VII and triggering blood coagulation. Quiescent DCs express the membrane-bound (full length), as well as truncated alternatively spliced TF forms. DC reactivity to anti-TF Abs disappeared almost completely on stimulation with ATP or benzoyl ATP (BzATP), as shown by immunoblot and confocal microscopy analysis. Concurrently, TF reactivity and activity appeared in the vesicular fraction, indicating that MPs are important carriers for the dissemination of full-length TF form. Activity of MP-bound TF, comparable to that of relipidated recombinant TF, was dose dependently inhibited by the addition of a specific anti-human TF antibody. We infer that a large fraction of this protein, and its procoagulant potential, are "deliverable" after physiological or pathological stimuli. These findings might have implications for triggering and propagating coagulation in healthy and atherosclerotic vessels.-. Stimulation of P2 (P2X 7 ) receptors in human dendritic cells induces the release of tissue factor-bearing microparticles. FASEB J. 21, 1926 -1933 (2007)

Objective-We investigated in patients with ongoing myocardial infarction (MI) whether coagulation factor VII (FVII) and tissue factor (TF) levels are affected at admission by genetic components and whether they may predict subsequent cardiovascular events. Methods and Results-256 patients admitted for MI were evaluated for FVII and TF antigen levels before any treatment at entry, and were genotyped for FVII and TF polymorphisms. FVII gene insertions at Ϫ323, 11293 and the Ϫ402G/A change predicted FVII levels and explained 14% of variance. The Ϫ603 TF gene polymorphism failed to affect significantly TF levels (Pϭ0.07). These variables were correlated with the incidence of death (36 patients) and reinfarction (9 patients) after a median follow-up of 397 days. Events were independently predicted by FVII (HR 2.1, 95% CI 1.2 to 5.7) and TF (HR 4.1, 95% CI 2 to 11) levels. Composite end point was significantly worse when both parameters were above the receiver-operating characteristics (ROC) values (HR 8.3, 95% CI 5 to 18, compared with FVII and TF below), and above the ROC value of TF (Ͼ630 pg/mL) it differed among FVII genotype groups. Conclusions-Admission

Decreased ADAMTS13, particularly in MS patients with cerebral microbleeds, which deserves further investigation, and increased PAI-1 and TFPI levels were observed in MS patients, which deserves further investigation. No relationship between hemostasis plasma levels and measures of disease severity was detected.

Olivieri O. Activated factor VII-antithrombin complex predicts mortality in patients with stable coronary artery disease: a cohort study.J Thromb Haemost 2016; 14: 655-66. Essentials• Activated factor VII-antithrombin complex (FVIIa-AT) in plasma may reflect tissue factor exposure.• FVIIa-AT levels were assessed in an angiographically controlled coronary artery disease (CAD) cohort.• High FVIIa-AT levels correlated with an increased thrombin generation.• High FVIIa-AT levels were associated with a greater risk of mortality in patients with stable CAD.Summary. Background: Plasma concentration of activated factor VII (FVIIa)-antithrombin (AT) complex has been proposed as an indicator of intravascular exposure of tissue factor. Objectives: The aims of this observational study were to evaluate (i) FVIIa-AT plasma concentration in subjects with or without coronary artery disease (CAD) and (ii) its association with mortality in a prospective cohort of patients with CAD. Methods: FVIIa-AT levels were measured by ELISA in 686 subjects with (n = 546) or without (n = 140) angiographically proven CAD. Subjects with acute coronary syndromes and those taking anticoagulant drugs at the time of enrollment were excluded. CAD patients were followed for total and cardiovascular mortality. Results: There was no difference in FVIIa-AT levels between CAD (84.8 with 95% confidence interval [CI] 80.6-88.2 pmol L -1 ) and CAD-free subjects (83.9 with 95% CI 76.7-92.8 pmol L -1 ). Within the CAD population, during a 64-month median followup, patients with FVIIa-AT levels higher than the median value at baseline (≥ 79 pmol L -1 ) had a two-fold greater risk of both total and cardiovascular mortality. Results were confirmed after adjustment for sex, age, the other predictors of mortality (hazard ratio for total mortality: 2.05 with 95% CI 1.22-3.45, hazard ratio for cardiovascular mortality 1.94 with 95% CI 1.01-3.73, with a slight improvement of C-statistic over traditional risk factors), FVIIa levels, drug therapy at discharge, and even patients using all the usual medications for CAD treatment. High FVIIa-AT levels also correlated with increased thrombin generation. Conclusions: This preliminary study suggests that plasma concentration of FVIIa-AT is a thrombophilic marker of total and cardiovascular mortality risk in patients with clinically stable CAD.

SummaryWe characterized a symptomatic CRMred factor X (FX) deficiency produced by the Glu19Ala mutation in the γ-carboxyglutamic-rich domain. FX activity levels in plasma were markedly reduced in prothrombin time assays (< 1-5%), whereas in activated partial thromboplastin assays (16%) and in RVV assays (17%) the reduction in activity mirrored that in antigen levels (17%). Activation of recombinant 19Ala-FX by factor IXa/factor VIIIa or RVV, and the activity in thrombin generation assays, were comparable to those of wild-type FX. Differently, complete activation of recombinant 19AlaFX required a factor VIIa/TF concentration 30-fold higher than that of wild-type FX. The recombinant FVIIa significantly reduced PT values in 19Ala-FX reconstituted plasma, thus suggesting an alternative approach for treatment of FX deficiencies characterized by defective FX activation.The study of this FX deficiency provides an “in vivo” and “in vitro” model for the investigation of Gla domain interactions.