thromboplastin and Fetal-Death

Recurrent fetal loss affects 1-5% of women of childbearing age. Immunological mechanisms may account for 40% of recurrent miscarriages, and in particular, the antiphospholipid syndrome (APS) appears to be implicated in 7-25% of the cases. Because antiphospholipid (aPL) antibodies have thrombogenic properties, fetal loss in patients with APS has been ascribed to thrombosis of placental vessels. However, we have shown that inflammation, specifically activation of complement with generation of the anaphylotoxin C5a, is an essential trigger of fetal injury. Thrombosis and inflammation are linked in many clinical conditions. Tissue factor (TF), the major cellular initiator of the coagulation protease cascade, plays important roles in both thrombosis and inflammation, and its expression is increased in patients with APS. Here we describe how TF, acting as a proinflammatory molecule, induces trophoblast injury and fetal death in a mouse model of APS. Importantly, we will discuss how TF contributes to C5a-induced oxidative burst in neutrophils leading to trophoblasts and fetal injury in APS. The finding that TF is an important effector in aPL-induced inflammation may allow the development of new therapies to abrogate the inflammatory loop caused by tissue factor and improve pregnancy outcomes in patients with aPL antibodies. Statins downregulate TF-induced inflammation and rescued the pregnancies in aPL-treated mice, suggesting they may be a good treatment for women with aPL-induced pregnancy complications.

Topics: Abortion, Habitual; Animals; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; Complement Activation; Disease Models, Animal; Embryo, Mammalian; Factor VIIa; Female; Fetal Death; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Mice; Neutrophil Activation; Pregnancy; Receptor, PAR-2; Thromboplastin; Thrombosis

The antiphospholipid syndrome (APS) is an autoimmune disorder presenting with tissue injury in various organs attributed to large or small vessel thrombosis or, in some instances, possible nonthrombotic inflammatory mechanisms, associated with in vitro evidence of antibodies to certain proteins, or proteinphospholipid complexes. Although the pathophysiology, diagnosis, and management of APS may seem clear and straightforward from a distance, closer inspection reveals a more complex, incomplete, and uncertain image. This article reviews the evolution of APS from the first description of lupus anticoagulant to the current criteria used to guide clinical research, critiques laboratory methods used to identify autoantibodies, comments on prognosis and management, and summarizes insights into the pathophysiology of this elusive disorder.

Topics: Antibodies, Anticardiolipin; Antiphospholipid Syndrome; beta 2-Glycoprotein I; Clinical Laboratory Techniques; Female; Fetal Death; Humans; Lupus Coagulation Inhibitor; Pregnancy; Thromboplastin

The paternal antigens presented by the fetus could be considered foreign by the mother's immune system and elicit an immune response. Here we show that the complement system functions as an effector in fetal rejection in two different mouse models of pregnancy loss. In a mouse model of fetal loss and growth restriction (IUGR) induced by antiphospholipid antibodies (aPL), we found that complement activation is a crucial and early mediator of pregnancy loss. We demonstrated that C5a-C5aR interaction and neutrophils are key mediators of fetal injury. We identified tissue factor (TF) as a critical intermediate that, acting downstream of C5 activation, enhances neutrophil activity and trophoblast injury. In an antibody-independent mouse model of spontaneous miscarriage and IUGR (CBAxDBA) we also identified C5a as an essential mediator. Complement activation caused dysregulation of the angiogenic factors (deficiency of free vascular endothelial growth factor (VEGF) and elevated levels of soluble VEGF receptor 1) required for normal placental development. Inhibition of complement activation prevented angiogenesis failure and rescued pregnancies. Our studies in antibody-dependent and antibody-independent models of pregnancy complications identified complement activation as the crucial mediator of damage and will allow development of new interventions to prevent pregnancy loss and IUGR.

Topics: Abortion, Spontaneous; Animals; Antibodies, Antiphospholipid; Anticoagulants; Complement Activation; Complement C5a; Complement Inactivating Agents; Female; Fetal Death; Fetal Growth Retardation; Growth Inhibitors; Humans; Macrophages; Mice; Neutrophils; Oxidative Stress; Pregnancy; Receptor, Anaphylatoxin C5a; Thromboplastin; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1

Fetal loss in patients with antiphospholipid antibodies (aPL) has been ascribed to thrombosis of placental vessels. However, we have shown that inflammation, specifically complement activation with generation of the anaphylotoxin C5a, is an essential mediator of fetal injury. We have analysed the role of tissue factor (TF) in a mouse model of aPL-induced pregnancy loss. TF is the major cellular activator of the coagulation cascade but also has cell signaling activity. Mice that received aPL-IgG showed strong TF staining throughout the decidua and on embryonic debris. This TF staining was not associated with either fibrin staining or thrombi in deciduas. The absence of fibrin deposition and thrombi suggests that TF-dependent activation of coagulation does not mediate aPL-induced pregnancy loss.We found that either blockade of TF with a monoclonal antibody in wild type mice or a genetic reduction of TF prevented aPL-induced inflammation and pregnancy loss indicated a pathogenic role for TF in aPL-induced pregnancy complications. In response to aPL-generated C5a, neutrophils express TF potentiating inflammation in the deciduas and leading to miscarriages. Importantly, we showed that TF in myeloid cells, but not fetal-derived cells (trophoblasts), was associated with fetal injury, suggesting that the site for pathologic TF expression is neutrophils. We found that TF expression in neutrophils contributes to respiratory burst and subsequent trophoblast injury and pregnancy loss induced by aPL. The identification of TF, acting as an important pro-inflammatory mediator in aPL-induced fetal injury, provides a new target for therapy to prevent pregnancy loss in the aPL syndrome.

Topics: Animals; Antibodies, Antiphospholipid; Antigen-Antibody Reactions; Antiphospholipid Syndrome; Disease Models, Animal; Female; Fetal Death; Humans; Mice; Pregnancy; Thromboplastin

Tissue factor (TF) is best known as the primary cellular initiator of blood coagulation. After vessel injury, the TF:FVIIa complex activates the coagulation protease cascade, which leads to fibrin deposition and activation of platelets. TF deficiency causes embryonic lethality in the mouse and there have been no reports of TF deficiency in humans. These results indicate that TF is essential for life, most likely because of its central role in hemostasis. In addition, aberrant TF expression within the vasculature initiates life-threatening thrombosis in various diseases, such as sepsis, atherosclerosis, and cancer. Finally, recent studies have revealed a nonhemostatic role of TF in the generation of coagulation proteases and subsequent activation of protease activated receptors (PARs) on vascular cells. This TF-dependent signaling contributes to a variety of biological processes, including inflammation, angiogenesis, metastasis, and cell migration. This review focuses on the roles of TF in hemostasis, thrombosis, and vascular development.

Topics: Animals; Blood Coagulation Factors; Blood Vessels; Coronary Vessels; Female; Fetal Death; Hemorrhage; Hemostasis; Humans; Mice; Mice, Knockout; Myocytes, Cardiac; Phenotype; Placenta; Postpartum Hemorrhage; Pregnancy; Pregnancy Complications, Hematologic; Thromboplastin; Thrombosis; Uterus; Yolk Sac

Topics: Anticoagulants; Female; Fetal Death; Fibrinolysis; Hemorrhagic Disorders; Humans; Infant, Newborn; Pregnancy; Pregnancy Complications, Hematologic; Thromboplastin

Topics: Abortion, Induced; Abruptio Placentae; Afibrinogenemia; Amniotic Fluid; Anticoagulants; Blood Coagulation Disorders; Embolism; Embolism, Amniotic Fluid; Female; Fetal Death; Fibrinolysis; History; Humans; Obstetrics; Postpartum Hemorrhage; Postpartum Period; Pregnancy; Pregnancy Complications; Pregnancy Complications, Hematologic; Thromboplastin

Antiphospholipid syndrome (APS) is characterized by thromboembolic phenomena and recurrent fetal loss associated with elevated circulating anti-phospholipid/beta2glycoprotein-I(β2GPI)-binding-antibodies(Abs). Individual APS patients harbor diverse clusters of circulating anti-β2GPI Abs, targeting different epitopes on the β2GPI molecule. Our novel approach was to construct a peptide composed of β2GPI-ECs-binding-site (phospholipids-membrane), named "EMBI". EMBI exert dual activities: a) At first EMBI prevented β2GPI ECs binding, thus reduced by 89% the binding of β2GPI/anti-β2GPI to the cells in comparison with 9.3% inhibition by EMBI scrambled form (scEMBI). b) Longer exposure of ECs to EMBI resulted in intracellular EMBI penetration which did not prevent β2GPI/anti-β2GPI binding to HUVEC. Surprisingly, β2GPI/anti-β2GPI did not activate ECs harboring EMBI, illustrated by prevention of E-selectin and tissue factor (TF) expression. The inhibition of TF mRNA transcription was illustrated by quantitative RT-PCR. EMBI decreased the expression of phosphorylated JNK1/2, p38, HSP27 and enhanced phosphorylation of glycogen synthase kinase-3β (pGSK3β). Knocking down the GSK3β expression by siRNA-GSK3β, reduced the TF expression by β2GPI/anti-β2GPI-exposed-HUVEC. In-vivo, EMBI significantly decreased the percentage of fetal loss in naïve mice infused with anti-β2GPI Abs, p<0.04. Thus, the dual activity of EMBI may introduce EMBI as a potential novel candidate peptide, to treat patients with APS.

Topics: Animals; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; beta 2-Glycoprotein I; Disease Models, Animal; E-Selectin; Endothelial Cells; Enzyme Inhibitors; Female; Fetal Death; Gene Expression Regulation, Enzymologic; Glycogen Synthase Kinase 3; Humans; Male; Mice; Mice, Inbred BALB C; Peptides; Phospholipids; Phosphorylation; Protein Binding; Protein Conformation; RNA, Messenger; Thromboplastin

Fetal death can lead to disseminated intravascular coagulation or fetal death syndrome. However, currently it is not clear what are the changes in the coagulation system in patients with a fetal death without the fetal death syndrome. This study was undertaken to determine: (1) whether fetal death in the absence of fetal death syndrome is associated with changes in hemostatic markers in maternal plasma and amniotic fluid; and (2) whether maternal hypertension or placental abruption are associated with further changes in the hemostatic profile of these patients.. A cross-sectional study included the following: (1) determination of changes in markers of coagulation and platelet activation in patients with a normal pregnancy (n = 71) and patients with fetal demise (FD) without disseminated intravascular coagulation (n = 65); (2) determination of the amniotic fluid (AF)-tissue factor concentration and activity, as well as the concentrations of thrombin-antithrombin III (TAT) complexes in patients with a normal pregnancy (n = 25) and those with a FD (n = 36) who underwent amniocentesis. Plasma and AF concentrations of TAT complexes and TF (an index of thrombin generation), as well as maternal plasma concentrations of sCD40L (a marker of platelet activation), tissue factor pathway inhibitor (TFPI) and prothrombin fragments (PF) 1 + 2 (also an indicator of in vivo thrombin generation) were measured by ELISA. TF and TFPI activity were measured using chromogenic assays.. (1) patients with FD without hypertension had a higher median maternal plasma sCD40L concentration than normal pregnant women (P < 0.001); (2) patients with FD had a higher median maternal plasma TAT III complexes than women with a normal pregnancy (P < 0.001); (3) the median AF-TF concentration and activity were higher in the FD group than in the normal pregnancy group (P < 0.001 for both); (4) patients with preeclampsia and FD had a higher median maternal plasma immunoreactive TF concentration than both normotensive patients with FD and women with normal pregnancies (P < 0.001 and P = 0.001, respectively); (5) the median plasma TF activity was higher in patients with preeclampsia and FD than that of women with normal pregnancies (P = 0.003); (6) among patients with a FD, those with placental abruption had a higher median AF-TAT complexes concentration than those without abruption (P = 0.0004).. Our findings indicate that: (1) mothers with a FD have evidence of increased in vivo thrombin generation and platelet activation than women with normal pregnancies; (2) patients with a FD and hypertension had a higher degree of TF activation than those with fetal death but without hypertension; (3) the AF of women with a FD had a higher median TF concentration and activity than that of normal pregnant women. AF can be a potential source for tissue factor and it participates in the development of fetal death syndrome in patients with a retained dead fetus.

Topics: Adult; Amniotic Fluid; Antithrombin III; CD40 Ligand; Cross-Sectional Studies; Female; Fetal Death; Humans; Lipoproteins; Peptide Fragments; Peptide Hydrolases; Platelet Activation; Pre-Eclampsia; Pregnancy; Protein Precursors; Prothrombin; Thrombin; Thromboplastin

Women with antiphospholipid syndrome (APS), a condition characterized by the presence of antiphospholipid antibodies (aPL), often suffer pregnancy-related complications, including miscarriage. We have previously shown that C5a induction of tissue factor (TF) expression in neutrophils contributes to respiratory burst, trophoblast injury, and pregnancy loss in mice treated with aPL. Here we analyzed how TF contributes to neutrophil activation and trophoblast injury in this model. Neutrophils from aPL-treated mice expressed protease-activated receptor 2 (PAR2), and stimulation of this receptor led to neutrophil activation, trophoblast injury, and fetal death. An antibody specific for human TF that has little impact on coagulation, but potently inhibits TF/Factor VIIa (FVIIa) signaling through PAR2, inhibited aPL-induced neutrophil activation in mice that expressed human TF. Genetic deletion of the TF cytoplasmic domain, which allows interaction between TF and PAR2, reduced aPL-induced neutrophil activation in aPL-treated mice. Par2-/- mice treated with aPL exhibited reduced neutrophil activation and normal pregnancies, which indicates that PAR2 plays an important role in the pathogenesis of aPL-induced fetal injury. We also demonstrated that simvastatin and pravastatin decreased TF and PAR2 expression on neutrophils and prevented pregnancy loss. Our results suggest that TF/FVIIa/PAR2 signaling mediates neutrophil activation and fetal death in APS and that statins may be a good treatment for women with aPL-induced pregnancy complications.

Topics: Animals; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; Disease Models, Animal; Factor VIIa; Female; Fetal Death; Gene Deletion; Gene Expression Regulation; Humans; Immunoglobulin G; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophil Activation; Neutrophils; Phagocytosis; Pregnancy; Reactive Oxygen Species; Receptor, PAR-1; Receptor, PAR-2; Respiratory Burst; Signal Transduction; Simvastatin; Thromboplastin

Fetal loss induced by antiphospholipid antibodies (aPLs) in mice is a complement-driven inflammatory condition. Engagement of the complement receptor C5aR on neutrophils induces expression of the principal initiator of the blood clotting mechanism, tissue factor (TF), and blocking this downstream event of complement activation prevents antibody-induced fetal loss. In this issue of the JCI, the study by Redecha et al. clarifies that in mice, the contribution of TF to this pathogenic mechanism is independent of its role in coagulation and thrombosis, but involves inflammatory signaling through the receptor PAR2 (see the related article beginning on page 3453). The study not only sheds light on a critical effector mechanism of aPL-induced fetal loss, but also suggests that treatment with statins, which decrease TF and PAR2 expression, may hold promise as a therapeutic approach to antiphospholipid syndrome-associated pregnancy complications.

Topics: Animals; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; Female; Fetal Death; Humans; Mice; Pregnancy; Pregnancy Complications, Hematologic; Receptor, PAR-2; Thromboplastin; Thrombosis

Estrogen sulfotransferase (EST, encoded by SULT1E1) catalyzes the sulfoconjugation and inactivation of estrogens. Despite decades of biochemical study and the recognition that high levels of estrogen sulfates circulate in the blood of pregnant and nonpregnant women, the physiological role of estrogen sulfation remains poorly understood. Here we show that ablation of the mouse Sult1e1 gene caused placental thrombosis and spontaneous fetal loss. This phenotype was associated with elevated free estrogen levels systemically and in the amniotic fluid, increased tissue factor expression in the placenta and heightened platelet sensitivity to agonist-induced activation ex vivo. Treatment of pregnant Sult1e1-null mice with either an anticoagulant or antiestrogen prevented the fetal loss phenotype. Our results thus identify Est as a critical estrogen modulator in the placenta and suggest a link between estrogen excess and thrombotic fetal loss. These findings may have implications for understanding and treating human pregnancy failure and intrauterine growth retardation.

Topics: Animals; Blood Platelets; Estrogens; Female; Fetal Death; Fetus; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Phenotype; Placenta; Pregnancy; Pregnancy, Animal; Sulfotransferases; Thromboplastin; Thrombosis

Antiphospholipid (aPL) syndrome (APS) is characterized by thromboembolic events, thrombocytopenia, or recurrent miscarriage associated with aPL Abs with specificity for beta2-glycoprotein-I (beta2GPI). We recently reported that at least 44% of patients with the APS possess circulating type 1 (Th1) CD4+ T cells that proliferate and secrete IFN-gamma when stimulated with beta2GPI in vitro. In this study, we show that stimulation of PBMCs from 20 APS patients with beta2GPI induced substantial monocyte tissue factor (TF) (80 +/- 11 TF stimulation index (TF-SI)), whereas no induction was observed using PBMCs from 13 patients with aPL Abs without APS (6 +/- 1 TF-SI) or 7 normal and 7 autoimmune controls (5 +/- 1 and 3 +/- 1 TF-SI, respectively) (p < 0.0001). TF induction on monocytes by beta2GPI was dose dependent and required CD4+ T lymphocytes and class II MHC molecules. Because monocyte TF induction by beta2GPI was observed in all patients with APS, but not in any patient with aPL Abs without APS, this response is a potentially useful predictor for APS in patients with aPL Abs, as well as providing mechanistic insight into thrombosis and fetal loss in these patients.

Topics: Antibodies, Antiphospholipid; Anticoagulants; beta 2-Glycoprotein I; Blood Coagulation Tests; CD4-Positive T-Lymphocytes; Dose-Response Relationship, Immunologic; Epitopes, T-Lymphocyte; Female; Fetal Death; Glycoproteins; Humans; Lymphocyte Activation; Male; Monocytes; T-Lymphocyte Subsets; Thromboplastin; Thrombosis

We determined the prevalence and relationship with clinical manifestations of antibodies to thromboplastin (aTP) in 92 patients with systemic lupus erythematosus (SLE). Thirty-two (35%) patients had aTP: 13 (14%) were positive for IgG aTP, 13 (14%) for IgM aTP, and 6 (7%) for both. Patients with aTP had an increased incidence of thrombosis (p = 0.01), thrombocytopenia (p < 0.001), hemolytic anemia (p < 0.001), and fetal losses (p = 0.03). When the IgG and IgM aTP isotypes were analysed separately, the IgG aTP were found to be associated with thrombosis (p < 0.001), thrombocytopenia (p < 0.001), and fetal losses (p = 0.02). The IgM aTP were associated with hemolytic anemia (p < 0.001). A correlation was found between the titers of aTP and those of anticardiolipin antibodies, in both IgG (p < 0.01, r = 0.6) and IgM (p < 0.01, r = 0.64) isotypes, and between the titers of IgG aTP and the diluted Russell's viper venom time used to detect the lupus anticoagulant (p < 0.001, r = 0.42). This test is a reliable, reproducible and sensitive assay for the detection of antiphospholipid antibodies, specially in those patients under anticoagulant therapy.

Topics: Adolescent; Adult; Aged; Anemia, Hemolytic, Autoimmune; Antibodies, Anticardiolipin; Antiphospholipid Syndrome; Autoantibodies; Case-Control Studies; Cohort Studies; Enzyme-Linked Immunosorbent Assay; Female; Fetal Death; Humans; Immunoglobulin G; Immunoglobulin Isotypes; Immunoglobulin M; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Middle Aged; Pregnancy; Reproducibility of Results; Sensitivity and Specificity; Thrombocytopenia; Thromboplastin; Thrombosis

Blood coagulation in vivo is initiated by factor VII (FVII) binding to its cellular receptor tissue factor (TF). FVII is the only known ligand for TF, so it was expected that FVII-deficient embryos would have a similar phenotype to TF-deficient embryos, which have defective vitello-embryonic circulation and die around 9.5 days of gestation. Surprisingly, we find that FVII-deficient (FVII-/-) embryos developed normally. FVII-/- mice succumbed perinatally because of fatal haemorrhaging from normal blood vessels. At embryonic day 9.5, maternal-fetal transfer of FVII was undetectable and survival of embryos did not depend on TF-FVII-initiated fibrin formation. Thus, the TF-/- embryonic lethal and the FVII-/- survival-phenotypes suggest a role for TF during embryogenesis beyond fibrin formation.

Topics: Animals; Blood Coagulation; Culture Techniques; Embryonic and Fetal Development; Factor VII; Female; Fetal Death; Fibrin; Gene Targeting; Hemorrhage; Hemostasis; Maternal-Fetal Exchange; Mice; Mice, Inbred C57BL; Mutagenesis; Pregnancy; Thromboplastin

The authors describe the case of gastroschisis and Dandy-Walker syndrome of the surviving fetus after the intra-uterine co-twin demise in a monochorionic twin pregnancy.

Topics: Abdominal Muscles; Adult; Dandy-Walker Syndrome; Diseases in Twins; Female; Fetal Death; Fetus; Humans; Infant, Newborn; Pregnancy; Thromboplastin; Twins, Monozygotic; Ultrasonography, Prenatal

Tissue factor (TF) is the cellular receptor for coagulation factor VI/VIIa and is the membrane-bound glycoprotein that is generally viewed as the primary physiological initiator of blood coagulation. To define in greater detail the physiological role of TF in development and hemostasis, the TF gene was disrupted in mice. Mice heterozygous for the inactivated TF allele expressed approximately half the TF activity of wild-type mice but were phenotypically normal. However, homozygous TF-/- pups were never born in crosses between heterozygous mice. Analysis of mid-gestation embryos showed that TF-/- embryos die in utero between days 8.5 and 10.5. TF-/- embryos were morphologically distinct from their TF+/+ and TF+/- littermates after day 9.5 in that they were pale, edematous, and growth retarded. Histological studies showed that early organogenesis was normal. The initial failure in TF-/- embryos appeared to be hemorrhaging, leading to the leakage of embryonic red cells from both extraembryonic and embryonic vessels. These studies indicate that TF plays an indispensable role in establishing and/or maintaining vascular integrity in the developing embryo at a time when embryonic and extraembryonic vasculatures are fusing and blood circulation begins.

Topics: Animals; Base Sequence; Blood Coagulation Disorders; DNA Primers; Fetal Death; Genes, Lethal; Hemorrhage; Heterozygote; Homozygote; Mice; Molecular Sequence Data; Phenotype; Thromboplastin

Tissue factor, a member of the cytokine-receptor superfamily and high-affinity receptor and cofactor for plasma factor VII/VIIa (ref. 1), is the primary cellular initiator of blood coagulation. It is involved in thrombosis and inflammation associated with sepsis, atherosclerosis and cancer, and can participate in other cellular processes including intracellular signalling, metastasis, tumor-associated angiogenesis, and embryogenesis. Here we report that inactivation of the tissue factor gene (TF) results in abnormal circulation from yolk sac to embryo beyond embryonic day 8.5, leading to embryo wasting and death. Vitelline vessels from null mice were deficient in smooth-muscle alpha-actin-expressing mesenchymal cells, which participate in organization of the vessel wall. This implies that tissue factor has a role in blood vessel development.

Topics: Animals; Blood Vessels; Chromosome Mapping; Culture Techniques; Fetal Death; Gene Targeting; Mice; Regional Blood Flow; Thromboplastin; Yolk Sac

Tissue factor (TF) is an integral membrane glycoprotein that is believed to be the physiologic initiator of the blood coagulation cascade. Disruption of the mouse tissue factor gene leads to embryonic lethality between days E9.5-E11.5 of gestation. On E9.5, TF(-/-) embryos appear indistinguishable from their TF(+/+) and TF(+/-) littermates. By E10.5, TF(-/-) embryos are severely growth retarded, appear nearly bloodless, and are in most cases dead. Initial observations suggest that TF(-/-) embryos are dying of circulatory failure. Approximately 15% of the TF(-/-) embryos survive beyond E10.5, but none complete gestation. Heterozygotes appear normal and free of bleeding complications.

Topics: Animals; Blood Coagulation; Chimera; Embryo, Mammalian; Female; Fetal Death; Fetal Growth Retardation; Gene Targeting; Genetic Vectors; Gestational Age; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Thromboplastin

Coagulation factor V is a critical cofactor for the activation of prothrombin to thrombin, the penultimate step in the generation of a fibrin blood clot. Genetic deficiency of factor V results in a congenital bleeding disorder (parahaemophilia), whereas inheritance of a mutation rendering factor V resistant to inactivation is an important risk factor for thrombosis. We report here that approximately half of homozygous embryos deficient in factor V (Fv-/-), which have been generated by gene targeting, die at embryonic day (E) 9-10, possibly as a result of an abnormality in the yolk-sac vasculature. The remaining Fv-/- mice progress normally to term, but die from massive haemorrhage within 2 hours of birth. Considered together with the milder phenotypes generally associated with deficiencies of other clotting factors, our findings demonstrate the primary role of the common coagulation pathway and the absolute requirement for functional factor V for prothrombinase activity. They also provide direct evidence for the existence of other critical haemostatic functions for thrombin in addition to fibrin clot formation, and identify a previously unrecognized role for the coagulation system in early mammalian development.

Topics: Animals; Crosses, Genetic; Embryonic and Fetal Development; Factor V; Factor V Deficiency; Female; Fetal Death; Gene Targeting; Hemorrhage; Homozygote; Male; Mice; Mice, Inbred C57BL; Thromboplastin

The hypothesis of our study is that antiphospholipid antibodies predispose to thrombosis by inducing endothelial cell tissue factor expression.. Monolayers of cultured human umbilical vein endothelial cells were incubated for 8 hours in a medium containing 20% serum obtained either from patients with antiphospholipid antibodies (n = 11) or normal subjects (n = 8). Similar incubations were performed with immunoglobulin G fractions from either patients with antiphospholipid antibodies (n = 3) or normal subjects (n = 3). Endothelial cell tissue factor expression was measured with a tissue factor-specific chromogenic substrate assay. The results were analyzed with a two-tailed t test.. The mean endothelial cell tissue factor expression induced by antiphospholipid sera was significantly greater than the controls (p < 0.02). Immunoglobulin experiments indicated that the factor(s) responsible for the induction of tissue factor expression resides in the immunoglobulin G fraction of the sera (p < 0.01).. Endothelial cell tissue factor expression is induced by antiphospholipid sera, with activity residing at least in part in the immunoglobulin fraction. The induction of tissue factor by antiphospholipid sera may play a role in the thrombotic tendency observed in patients with antiphospholipid syndrome.

Topics: Antibodies, Antiphospholipid; Cells, Cultured; Endothelium, Vascular; Female; Fetal Death; Humans; Male; Thromboplastin; Thrombosis; Umbilical Veins

Twenty-three patients with the 'primary' antiphospholipid syndrome were studied over 2-6 years. Twenty-two (96%) had antiphospholipid antibodies detected by ELISA (87% had antibodies to thromboplastin and 70% to cardiolipin), and 18 out of the 21 tested patients (86%) had lupus anticoagulant activity by coagulative assays. Mean age of the cohort was 29.9 years and the sex ratio (female:male) 4.75:1. Eleven patients presented 18 venous and/or arterial thrombosis and 13 had 25 foetal losses (84% occurred during the second and third trimester). Other clinical features were migraine, livedo reticularis, and epilepsy. Three patients had relatives with systemic lupus erythematosus. Thrombocytopaenia was seen in 33%, antinuclear antibodies in low or moderate titre in 30%, and haemolytic anaemia in 13%. During the follow-up, two patients presented recurrent thrombosis despite anticoagulant therapy, one of them dying because of recurrent pulmonary thromboembolism. Four patients achieved successful term pregnancies after treatment with aspirin and a further patient after treatment with aspirin and low dose prednisolone. No patient developed systemic lupus erythematosus or any other definable connective tissue disease. The 'primary' antiphospholipid syndrome may exist as a distinct clinical entity and all younger patients presenting with thrombotic events, foetal losses and/or thrombocytopaenia, without any evidence of a well defined disease, should be tested for antiphospholipid antibodies in order to rule out this syndrome.

Topics: Adult; Antibodies, Anticardiolipin; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; Aspirin; Enzyme-Linked Immunosorbent Assay; Female; Fetal Death; Humans; Lupus Coagulation Inhibitor; Male; Middle Aged; Pregnancy; Pregnancy Complications; Thromboplastin; Thrombosis

The relationship between abortive disease and systemic lupus erythematosus is complex as shown by data from the literature and by our 9 patients selected for presenting with abortive disease, circulating anticoagulant and biological signs of autoimmunity. The risk of transformation into a systemic disease is real, although difficult to evaluate in the absence of prospective studies, but the major problem with these patients is the severity of the obstetrical pathology. The sombre foetal prognosis, already reported in the literature, requires close supervision and sustained treatment during pregnancy. For these reasons we suggest calling autoimmune abortive disease the disease which affects women with signs of autoimmunity who have had several, often late foetal deaths associated with the presence of circulatory anticoagulant thought to interfere with placental blood flow.

Topics: Abortion, Habitual; Adult; Antibodies, Antinuclear; Autoantibodies; Autoimmune Diseases; Blood Coagulation Factors; Female; Fetal Death; Humans; Lupus Coagulation Inhibitor; Pregnancy; Prognosis; Thromboplastin

This study describes the use of a modified dilute thromboplastin assay for demonstration of the lupus coagulation inhibitor in plasma. A one-stage clotting inhibition assay is used in which the ability of the test plasma to prolong the clotting time of normal plasma is measured. The method is easy to perform and suitable for routine use. Clinical and laboratory data from five patients with the inhibitor but without systemic lupus erythematosus are presented. Thromboembolic manifestations were observed in three patients and obstetric complications possibly due to placenta thrombosis in two. One patient showed a bleeding tendency, associated with prothrombin deficiency. A number of pathological coagulation analyses and other laboratory data may be due to affinity of the lupus inhibitor for negatively charged phospholipids in vitro.

Topics: Abortion, Spontaneous; Adult; Anticoagulants; Blood Coagulation Factors; Blood Coagulation Tests; Female; Fetal Death; Humans; Lupus Coagulation Inhibitor; Pregnancy; Pregnancy Complications, Cardiovascular; Thromboembolism; Thromboplastin

Monozygotic twinning has been associated with a variety of vascular disruptive defects including congenital hydranencephaly/porencephaly. Data involving 24 cases of congenital hydranencephaly/porencephaly associated with twinning are reported. In these cases, the finding of a preponderance of monozygotic twins and the common association of a deceased co-twin support the hypothesis of a vascular disruptive etiology. These defects are presumed to be secondary to embolic phenomena or thromboplastin release from the deceased co-twin to the survivor via the vascular interconnections of a conjoined monochorionic placenta. In all cases of hydranencephaly/porencephaly, a careful examination of the placenta and membranes for evidence of a deceased co-twin is warranted prior to providing recurrence risk counseling.

Topics: Anencephaly; Brain; Diseases in Twins; Disseminated Intravascular Coagulation; Embolism; Female; Fetal Death; Humans; Hydranencephaly; Infant, Newborn; Male; Placenta; Pregnancy; Thromboplastin; Twins; Twins, Monozygotic

We discovered a "lupus' anticoagulant in 2 out of 42 women with a history of repeated abortions, intrauterine growth retardation and intrauterine death of unknown origin. The "lupus' anticoagulant was detected by an abnormal dilute tissue thromboplastin assay(prothrombin time performed with dilute thromboplastin). The production of prostacyclin by fresh or exhausted rings of rat aorta was decreased by the plasma of one of these two patients with a "lupus' anticoagulant. In view of the increasing evidence for a physiological role of prostacyclin in pregnancy and fetal life, we suggest that an inhibition of prostacyclin production could compromise fetal outcome.

Topics: Abortion, Habitual; Adult; Animals; Aorta; Biological Assay; Blood Coagulation Factors; Epoprostenol; Female; Fetal Death; Fetal Growth Retardation; Humans; Lupus Coagulation Inhibitor; Partial Thromboplastin Time; Pregnancy; Prostaglandins; Prothrombin Time; Rats; Thromboplastin

A clinical study was done of 80 patients in whom abruptio placentae was severe enough to cause intra-uterine death of the fetus. Central venous pressure pressure was measured when ever possible to ensure adequate fluid replacement. Although the minority of the patients were shocked when admitted, blood replacement averaged 5 units per patient. The caesarean section incidence was 21%. Only 1 patient developed renal failure for which peritoneal dialysis was done. No maternal deaths occurred. Serial coagulation studies were done in 58 patients. Diffuse intravascular coagulation was present in the majority. After delivery of the fetus, however, tests became normal.

Topics: Abruptio Placentae; Adolescent; Adult; Blood Cell Count; Blood Platelets; Female; Fetal Death; Fibrin Fibrinogen Degradation Products; Fibrinogen; Humans; Middle Aged; Pregnancy; Pregnancy Complications, Cardiovascular; Prothrombin; Thrombin; Thromboplastin

A report is presented of a young, otherwise apparently healthy, woman who had three pregnancies which for some unknown reason terminated in intrauterine death (macerated foetuses). During the third pregnancy a coagulation defect was diagnosed, which was characterized by prolonged coagulation times and prolonged one-stage prothrombin time. This defect disappeared after the end of the pregnancy, but returned during the fourth pregnancy. This time a circulating anticoagulant was found, which inhibited the action of thromboplastin. The values found for the various coagulation factors were normal. The anticoagulant titre rose during the pregnancy from 1/2 to 1/10. Leucocyte agglutinating as well as lymphocytotoxic antibodies directed against the husband's cells were demonstrated in the patient during the pregnancy. In this case, by passage of cell fragments and thromboplastic substances to the mother, the foetus had probably induced the development of antibodies against the foetal tissues. The foetus may be regarded as an incompatible transplant. The fourth pregnancy was terminated by caesarean section in the 34th week. The child weighed 1440 g and, after three exchanges of blood, did very well. The placenta was severely infarcted. It is postulated that the development of antithromboplastin during pregnancy may be a contributory cause of intrauterine death.

Topics: Adult; Antibodies; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Female; Fetal Death; Fibrinolytic Agents; Humans; Male; Pregnancy; Pregnancy Complications; Thromboplastin; Time Factors

Topics: Abortion, Septic; Blood Coagulation Disorders; Embolism, Amniotic Fluid; Female; Fetal Death; Fibrinolysis; Gelatin; Hemorrhagic Disorders; Humans; Hydrogen-Ion Concentration; Placenta; Placenta Diseases; Plasma Substitutes; Pregnancy; Pregnancy Complications; Pulmonary Embolism; Shock, Hemorrhagic; Shock, Septic; Streptokinase; Thrombophlebitis; Thromboplastin; Thrombosis

Topics: Animals; Autopsy; Cricetinae; Eclampsia; Female; Fetal Death; Fibrin; Humans; Infant Mortality; Infant, Newborn; Kidney Glomerulus; Lung; Maternal-Fetal Exchange; Methods; Microcirculation; Placenta; Placenta Diseases; Pregnancy; Pregnancy Complications; Thromboplastin; Time Factors

Topics: Abortion, Spontaneous; Adult; Afibrinogenemia; Blood Coagulation Tests; Female; Fetal Death; Fibrinogen; Heparin; Humans; Pregnancy; Thromboplastin

Topics: Abruptio Placentae; Afibrinogenemia; Aminocaproates; Aminocaproic Acid; Blood Coagulation Tests; Blood Transfusion; Calcium; Dexamethasone; Drug Therapy; Female; Fetal Death; Fibrinogen; Fibrinolysin; Hemorrhagic Disorders; Humans; Pregnancy; Pregnancy Complications, Hematologic; Thrombin; Thromboplastin; Tolonium Chloride; Uterine Hemorrhage