Procoagulant Phospholipids and Tissue Factor Activity in Cerebrospinal Fluid from Patients with Intracerebral Haemorrhage

Brain contains large amounts of tissue factor, the major initiator of the coagulation cascade. Neuronal apoptosis after intracerebral haemorrhage (ICH) leads to the shedding of procoagulant phospholipids (PPLs). The aim of this study was to investigate the generation of PPL, tissue factor activity (TFa), and D-Dimer (D-Di) in the cerebrospinal fluid (CSF) at the acute phase of ICH in comparison with other brain diseases and to examine the relationship between these factors and the outcome of ICH. CSF was collected from 112 patients within 48 hours of hospital admission. Thirty-one patients with no neurological or biochemical abnormalities were used to establish reference range in the CSF (“controls”). Thirty had suffered an ICH, and 51 other neurological diagnoses [12: ventricular drainage following brain surgery, 13: viral meningitis, 15: bacterial meningitis, and 11 a neurodegenerative disease (NDD)]. PPL was measured using a factor Xa-based coagulation assay and TFa by one home test. PPL, D-Di, and TFa were significantly higher (P<0.001) in the CSF of patients with ICH than in controls. TFa levels were significantly (P<0.05) higher in ICH than in patients with meningitides or NDD. Higher levels (P<0.05) of TFa were observed in patients with ICH who died than in survivors. TFa measurement in the CSF of patients with ICH could constitute a new prognostic marker

Is the general time-reversible model bad for molecular phylogenetics?

The general time reversible model (GTR) is presently the most popular model used in phylogentic studies. However, GTR has an undesirable mathematical property that is potentially of significant concern. It is the purpose of this article to give examples that demonstrate why this deficit may pose a problem for phylogenetic analysis and interpretation.Comment: 10 pages, 2 figure

Toward standardization of assays measuring extracellular vesicle-associated tissue factor activity.

The clinical and scientific interest in extracellular vesicles (EVs) is growing exponentially. The term EVs is an umbrella term for various types of vesicles that are present in body fluids and other (bio)fluids. This umbrella term is used because clear hallmarks to distinguish different types of EVs from each other are lacking. Thus, the term “EVs” encompasses earlier “microparticles” or “microvesicles” and exosomes, which are vesicles released directly from the plasma membrane or by secretion of intraluminal vesicles stored in multivesicular endosomes, respectively.1, 2 There is evidence that EVs play a role in intercellular communication and contribute to coagulation and likely inflammation [...

Origin and levels of circulating microparticles in normal pregnancy: A longitudinal observation in healthy women

Objective. Microparticles (MP) are actively involved in the hypercoagulable state reported both in normal pregnancies and in pregnancy diagnosed with placenta-mediated complications. In this study the origin and the levels of plasma MP as well as MP activity were evaluated in a group of healthy women during the three trimesters of a normal pregnancy. Materials and methods. Seventy-five healthy normotensive pregnant women were enrolled and blood samples were prospectively collected at three different time points corresponding to 1st trimester, 2nd trimester, 3rd trimester of pregnancy. A group of age- matched healthy non-pregnant women acted as controls. Both standard clotting parameters and MP of different origin were measured. MP were identified by size and annexin V- FITC labelling using flow-cytometer. MP subtypes were identified using specific monoclonal antibodies. Procoagulant activity of MP was assessed using the STA\uae Procoag PPL assay. Results. The levels of total, platelet-, endothelial-, leukocyte-derived and tissue factor-bearing MP, as well as the MP procoagulant activity, in non-complicated pregnancy were higher in the 1st trimester as compared to non-pregnant age-matched women. Regardless of the origin, MP levels gradually increase during pregnancy, with the highest values reached in the 3rd trimester. Conclusions. MP levels gradually increase during normotensive pregnancy. All types of MP including TF+ present with the highest levels in the 3rd trimester. MP convey prothrombotic and proinflammatory antigens already from the first trimester of normal pregnancy. This may contribute to the global hypercoagulable state observed, particularly in the last months of pregnancy, also in healthy wome

Aptamer-modified FXa generation assays to investigate hypercoagulability in plasma from patients with ischemic heart disease

Background: High plasma levels of activated Factor VII-Antithrombin complex (FVIIa-AT) have been associated with an increased risk of cardiovascular mortality in patients with stable coronary artery disease (CAD). Objectives: To investigate if FVIIa-AT levels are associated with activated factor X generation (FXaG) in modified assays. Patients/methods: Forty CAD patients were characterized for FVIIa-AT levels by ELISA and for FXaG in plasma. Novel fluorogenic FXaG assays, based on aptamers inhibiting thrombin and/or tissue factor pathway inhibitor (TFPI), were set up. Results: FXaG correlated with FVIIa-AT levels (RAUC = 0.393, P = 0.012). The combination of thrombin inhibition and FXaG potentiation by using anti-thrombin and anti-TFPI aptamers, respectively, favors the study of time parameters. The progressive decrease in lag time from the lowest to the highest FVIIa-AT quartile was magnified by combining TFPI and thrombin inhibitory aptamers, thus supporting increased FXaG activity in the coagulation initiation phase. By exploring FXaG rates across FVIIa-AT quartiles, the largest relative differences were detectable at the early times (the highest versus the lowest quartile; 5.0-fold, P = 0.005 at 45 s; 3.5-fold, P = 0.001 at 55 s), and progressively decreased over time (2.3-fold, P = 0.002 at 75 s; 1.8-fold, P = 0.008 at 95 s; 1.6-fold, P = 0.022 at 115 s). Association between high FVIIa-AT levels and increased FXaG was independent of F7 -323 A1/A2 polymorphism influencing FVIIa-AT levels. Conclusions: High FVIIa-AT plasma levels were associated with increased FXaG. Hypercoagulability features were specifically detectable in the coagulation initiation phase, which may have implications for cardiovascular risk prediction by either FVIIa-AT complex measurement or modified FXaG assays