thromboplastin and Intracranial-Hemorrhages

Anticoagulants are effective at preventing and treating thrombosis, but can cause bleeding. For decades, vitamin K antagonists (VKAs) have been the only available oral anticoagulants. The development of non-VKA oral anticoagulants (NOACs), which inhibit either factor Xa or thrombin stoichiometrically, has provided alternatives to VKAs for several indications. The results of recent large-scale randomised controlled trials comparing NOACs with VKAs for the prevention of stroke in patients with non-valvular atrial fibrillation (AF) have produced some unexpected results. As a group, NOACs showed similar efficacy as warfarin, but a reduced risk of major bleeding. The reduction in bleeding with NOACs was greatest with intracranial hemorrhage. In contrast, the relative risk of gastro-intestinal bleeding was increased with some NOACs. In this review, we explore the potential mechanisms as well as the implications of these organ-specific bleeding patterns.

Topics: Anticoagulants; Atrial Fibrillation; Blood Coagulation Factors; Endothelium, Vascular; Factor Xa Inhibitors; Gastrointestinal Hemorrhage; Hemorrhage; Humans; International Normalized Ratio; Intestinal Absorption; Intracranial Hemorrhages; Organ Specificity; Randomized Controlled Trials as Topic; Stroke; Thrombophilia; Thromboplastin; Vitamin K; Warfarin

Tissue factor (TF) expression is increased in inflammatory atherosclerotic plaques and has been related to their thrombogenicity. Blood-borne TF has been also demonstrated to contribute to thrombogenesis. However, few studies have evaluated the association of circulating levels of TF with stroke. We investigated the association of baseline circulating levels of TF with stroke events occurred in the European Prospective Investigation into Cancer and Nutrition-Italy cohort.. Using a nested case-cohort design, a center-stratified random sample of 839 subjects (66% women; age range, 35-71 years) was selected as subcohort and compared with 292 strokes in a mean follow-up of 9 years. Blood samples were collected at baseline in citrate, plasma was stored in liquid nitrogen and TF was measured by ELISA (IMUBIND, TF ELISA, Instrumentation Laboratory, Milan, Italy). The odd ratios and 95% confidence intervals, adjusted by relevant confounders (covariates of TF) and stratified by center, were estimated by a Cox regression model using Prentice method.. Individuals in the highest compared with the lowest quartile of TF plasma levels had significantly increased risk of stroke (odds ratioIVvsI quartile, 2.01; 95% confidence interval, 1.25-3.23). The association was independent from several potential confounders (odds ratioIVvsI quartile, 1.91; 95% confidence interval, 1.15-3.19). No differences were observed between men and women. The increase in risk was restricted to ischemic strokes (odds ratioIVvsI quartile, 2.13; 95% confidence interval, 1.10-4.12; fully adjusted model), whereas high levels of TF were not associated with the risk of hemorrhagic stroke (odds ratioIVvsI quartile, 1.12; 95% confidence interval, 0.49-2.55; fully adjusted model).. Our data provide evidence that elevated levels of circulating TF are potential risk factors for ischemic strokes.

Topics: Adult; Aged; Brain Ischemia; Female; Follow-Up Studies; Humans; Intracranial Hemorrhages; Italy; Male; Middle Aged; Prospective Studies; Risk Factors; Stroke; Thromboplastin

Very premature infants are at high risk of bleeding complications; however, few data exist on ranges for standard coagulation tests.. The primary objective of this study was to measure standard plasma coagulation tests and thrombin generation in very premature infants compared with term infants. The secondary objective was to evaluate whether an association existed between coagulation indices and intraventricular hemorrhage (IVH).. Cord and peripheral blood of neonates < 30 weeks gestational age (GA) was drawn at birth, on days 1 and 3 and fortnightly until 30 weeks corrected gestational age. Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and coagulation factor levels were measured and tissue factor-stimulated thrombin generation was characterized. Control plasma was obtained from cord blood of term neonates.. One hundred and sixteen infants were recruited. Median (range) GA was 27.7 (23.7-29.9) weeks and mean (SD) birth weight was 1020 (255) g. Median (5th-95th percentile) day 1 PT, APTT and fibrinogen were 17.5 (12.7-26.6) s, 78.7 (48.7-134.3) s and 1.4 (0.72-3.8) g L(-1) , respectively. No difference in endogenous thrombin potential between preterm and term plasma was observed, where samples were available. Levels of coagulation factors II, VII, IX and X, protein C, protein S and antithrombin were reduced in preterm compared with term plasma. Day 1 APTT and PT were not associated with IVH.. In the largest cross-sectional study to date of very preterm infants, typical ranges for standard coagulation tests were determined. Despite long clotting times, thrombin generation was observed to be similar in very preterm and term infants.

Topics: Blood Coagulation Factors; Blood Coagulation Tests; Blood Component Transfusion; Cerebral Ventricles; Cross-Sectional Studies; Female; Fetal Blood; Fibrinogen; Gestational Age; Hemorrhagic Disorders; Humans; Infant, Newborn; Infant, Premature; Infant, Small for Gestational Age; Intensive Care, Neonatal; Intracranial Hemorrhages; Male; Partial Thromboplastin Time; Prospective Studies; Prothrombin Time; Recombinant Proteins; Reference Standards; Thrombin; Thromboplastin; Vitamin K

Maternal anti-HPA-1a antibodies can cause severe fetal and neonatal alloimmune thrombocytopenia (FNAIT), complicated by intracranial haemorrhage (ICH). Antenatal treatment with maternal intravenous immunoglobulin (IVIG) seems to protect against ICH even when thrombocytopenia persists. The aim of this study was to investigate if anti-HPA-1a antibodies and IVIG potentially affect vascular endothelial cells (ECs) in order to identify susceptibility for ICH. Human umbilical cord endothelial cells (HUVEC) were incubated with anti-HPA-1a antibodies with or without polyclonal IVIG and evaluated for EC activation. Maternal sera with anti-HPA-1a antibodies affected neither the EC expression of intracellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) and tissue factor (TF) nor the release of van Willebrand factor (vWF) or interleukin (IL)-8 nor the integrity of ECs. Maternal sera obtained after IVIG treatment and polyclonal IVIG decrease constitutive and cytokine-induced ICAM-1 and VCAM-1 expression on ECs. The results show that maternal anti-HPA-1a antibodies cause no activation or damage of ECs in this model. The clinical relevance of the de-activating properties of IVIG on EC activation with respect to ICH deserves further investigation.

Topics: Antibodies, Anti-Idiotypic; Antigens, Human Platelet; Endothelial Cells; Female; Fetal Blood; Humans; Immunoglobulins, Intravenous; Infant, Newborn; Integrin beta3; Intercellular Adhesion Molecule-1; Interferon-gamma; Interleukin-8; Intracranial Hemorrhages; Maternal-Fetal Exchange; Pregnancy; Thromboplastin; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1; von Willebrand Factor

Haemorrhage from meningiomas is rare and the underlying pathophysiological mechanisms remain to be determined. We sought to identify these mechanisms by studying clinical and histological records of 6 meningioma patients treated at our institution.. We retrospectively studied 6 patients with meningiomas whose acute onset was due to haemorrhage. We evaluated clinical features and imaging studies. The vascularity and proliferative nature of these tumours were examined immunohistochemically and tissue factor (TF) immunoreactivity was assessed. For comparison we evaluated 25 non-haemorrhagic meningiomas.. At onset, the haemorrhages mimicked stroke in all 6 patients. On imaging studies, 3 of the haemorrhages were intra- and extratumoural, the other 3 were extratumoural only. Hyperintensity on T2-weighted MRI was a characteristic of these meningiomas. Histologically, they were of 3 subtypes, meningothelial (n=3), transitional (n=2), and anaplastic (n=1). The MIB-1 labelling index of the 5 WHO Grade I meningiomas was 5.8+/-2.2. The mean number of CD31-positive blood vessels did not differ in haemorrhagic and non-haemorrhagic meningiomas. The TF-positivity rate of haemorrhagic meningiomas was higher than of non-haemorrhagic meningiomas.. The proliferative nature of the meningiomas and TF expression in tumour cells may have contributed to the eventual haemorrhage of the meningiomas in our series.

Topics: Aged; Aged, 80 and over; Blood Coagulation; Female; Humans; Intracranial Hemorrhages; Male; Meningeal Neoplasms; Meningioma; Middle Aged; Neovascularization, Pathologic; Retrospective Studies; Thromboplastin

To obtain better insight into the pathogenesis of verotoxin-producing Escherichia coli-associated diseases, in this study, we explored the effect of verotoxin 2 (VT2) on coagulation in an animal model. After being given VT2 (50 ng/kg, lethal dose), C57BL/6 mice showed progressively increasing expression of TF mRNA in the kidney and brain and elevated plasma levels of thrombin-antithrombin III complex (TAT), normotest, fibrinogen, and PAI-1 paralleling the disease course over 24 hours; platelet counts were decreased at 48 hours with hemorrhage in the kidney and brain. Co-administration of lipopolysaccharide (LPS, 0.5 mg/kg) with VT2 (50 ng/kg) exhibited more prominant and/or prolonged increase in not only expression of TF and PAI-1 mRNAs in the kidney and brain but also plasma levels of TAT, fibrinogen, and PAI-1 and was associated with more remarkable hemorrhage in the tissues. Although VT2 (5 ng/kg) was not a lethal dose, co-administration of LPS (0.5 mg/kg) with VT2 (5 ng/kg) enhanced the susceptibility to VT2, resulting in more prolonged elevation of TAT levels during the first 24 hours than that in the LPS group and a second elevation at 72 hours, followed by death. Plasma IL-1beta level reached a maximum at 24 hours after VT2 (50 ng/kg) injection prior to the increase in TAT levels, whereas the increase in TNFalpha level immediately after injection was associated with the increase in PAI-1 mRNA. These observations indicate that the activation of coagulation by VT2 may occur through a mechanism different from that used by LPS, since plasma TAT levels rose in the mice immediately after LPS injection and returned to normal over 36 hours.

Topics: Animals; Antithrombin III; Blood Coagulation; Blood Coagulation Tests; Brain; Cytokines; Dose-Response Relationship, Drug; Drug Therapy, Combination; Fibrinogen; Hemorrhage; Intracranial Hemorrhages; Kidney; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Models, Animal; Neutrophils; Peptide Hydrolases; Plasminogen Activator Inhibitor 1; Platelet Count; RNA, Messenger; Shiga Toxin 2; Shock; Thromboplastin; Time Factors; Tissue Distribution