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Introduction: Treatment of venous thromboembolism (VTE) in cancer patients with thrombocytopenia is challenging due to perceived higher risk of bleeding., Material and Methods: We used the RIETE registry to compare the 10- and 30-day outcomes in cancer patients with acute VTE, according to platelet count at baseline., Results: As of December 2018, 15,337 cancer patients with VTE were included: 166 (1.1%) had <50 × 10 9  platelets/L (severe thrombocytopenia), 711 (4.6%) had 50-99 × 10 9 /L (mild thrombocytopenia) and 14,460 (94.3%) had ≥100 × 10 9 /L (normal count). Most patients in all subgroups received initial therapy with low-molecular-weight heparin (LMWH), but 62% of those with severe thrombocytopenia received <150 IU/kg/day LMWH, 42% received <100 IU/kg/day. The mortality rate progressively decreased with increasing platelet counts (12%, 9.4% and 3.3% respectively at 10 days, 27%, 18% and 9.4% at 30 days), but the major bleeding rates did not (1.2%, 2.5% and 1.3% respectively at 10 days, 2.4%, 4.4% and 2.2% at 30 days). On multivariable analysis, patients with severe thrombocytopenia had a similar risk for major bleeding at 10 days (OR 0.84; 95%CI 0.20-3.49) and at 30 days (OR 0.90; 95%CI 0.32-2.49), but those with mild thrombocytopenia were at increased risk both at 10 days (OR 2.11; 95%CI 1.27-3.49) and at 30 days (OR 1.91; 95%CI 1.29-2.84)., Conclusions: Cancer patients with acute VTE and baseline thrombocytopenia often receive initial lower-than recommended doses of LMWH. Although caution is required, this practice seems to be safe in patients with severe thrombocytopenia. Nonetheless, there was an inverse correlation between baseline platelet count and mortality., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objective: To address the association between psychiatric disorders and short-term outcomes after acute symptomatic pulmonary embolism (PE)., Methods: We identified adults with PE enrolled in the RIETE registry between December 1, 2013, and January 31, 2019. Using multinomial regression, we assessed the association between a history of psychiatric disorders and the outcomes of all-cause mortality, PE-related mortality, and venous thromboembolism recurrence and bleeding rates through 30 days after initiation of treatment. We also examined the impact of depression on all-cause and PE-specific mortality., Results: Among 13,120 patients diagnosed with acute PE, 16.1% (2115) had psychiatric disorders and 4.2% died within the first 30-days of follow-up. Patients with psychiatric disorders had increased odds for all-cause (adjusted odds ratio [OR] 1.50; 95% CI, 1.21 to 1.86; P < 0.001) and PE-related mortality (adjusted OR 1.64; 95% CI, 1.09 to 2.48; P = 0.02) compared to those without psychiatric disorders. Multinomial logistic regression showed a non-significant trend toward lower risk of recurrences for patients with psychiatric disorders (adjusted OR 0.49; 95% CI, 0.21 to 1.15; P = 0.10). Psychiatric disorders were not significantly associated with increased odds for major bleeds during follow-up (adjusted OR 1.09; 95% CI, 0.85 to 1.40; P = 0.49). Results were consistent in a sensitivity analysis that only considered patients with a diagnosis of depression., Conclusions: In patients with acute PE, history of psychiatric disorders might predict all-cause and PE-related death in the ensuing month after diagnosis., Competing Interests: Declaration of competing interest Dr. Bikdeli reports that he has been a consulting expert (on behalf of the plaintiff) for litigation related to a specific type of IVC filters. The current study is the idea of the investigators and has not been performed at the request of a third party., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A B S T R A C T Thrombotic events are a major cause of morbidity and mortality in cancer. While the association of venous thromboembolic events with cancer is well documented, in recent years arterial events (i.e. acute myocardial infarction and ischemic strokes) have also emerged as relatively common complications among cancer patients. In hematological malignancies incorporating a heterogeneous group of diseases, the prediction of thrombosis occurrence and/or recurrence is challenging, due to unique disease characteristics. Furthermore, the treatment of thrombosis in these patients is often complicated because of disease- or therapy-related thrombocytopenia. In addition, patients with hematological cancers are poorly represented in randomized control clinical trials; hence, evidence-based guidelines are limited. This review will discuss the incidence of venous and arterial thrombotic events in common myeloid and lymphoproliferative diseases. Several new mechanisms contributing to cancer- associated thrombosis will be elaborated. The complicated issue of risk assessment and management of venous thrombosis in patients with hematological malignancies will be delineated., (© 2020 Elsevier Ltd. All rights reserved.)

Background: Arterial hypertension is associated with greater risk of cardiovascular diseases and thrombotic complications, suggesting that hypertension is a prothrombotic state., Objectives: To investigate the relationship between arterial hypertension and thrombin generation, and between blood pressure level and thrombin generation in hypertensive patients., Methods: A total of 165 hypertensive patients and 47 healthy adults controls were include in the study. Thrombin generation was assessed in both groups by the Calibrated Automated Thrombogram (CAT) method. Ambulatory blood pressure monitoring (ABPM) was also performed for all patients in the hypertensive group., Results: Hypertensive patients had significantly higher levels of ETP and peak heights compared to healthy controls; means of ETP 1720.6 ± 267 and 1544.7 ± 302, respectively (P < 0.001) and means of peak height were 297.26 ± 48 and, 273 ± 53, respectively (P < 0.001). On multivariate linear regression analysis, hypertension remained independently associated with increased ETP (β = 0.185, P = 0.047). Analysis restricted to the hypertensive group with ABPM measurement showed statistically significant correlations between all measures of diastolic blood pressure (DBP) and ETP, and multivariate analysis showed that awake DBP was significantly associated with ETP (β = 0.194 for each 1-mm Hg increase in awake DBP, P = 0.012). Furthermore, hypertensive patients with cardiovascular complications had statistically elevated levels of peak height compared to hypertensive patients without cardiovascular complications., Conclusions: Hypertensive patients possess enhanced thrombin generation compared healthy controls. Diastolic blood pressure level is independently correlated with increased thrombin generation in hypertensive patients. These findings suggest that arterial hypertension is a prothrombotic state., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Cancer-associated arterial thrombotic events (ATEs) are increasingly recognized in specific malignancies and in association with the expanding armamentarium of novel chemotherapeutic agents. The improved cancer survival led to cardiovascular complications becoming clinically relevant many years after cancer diagnosis. The pathobiology of ATEs in cancer is complex and the individual patient risk for an ATE entails a multifactorial interaction between the traditional cardiovascular risk factors and comorbidities, the specific malignancy and selected therapy. Treatment with several specific chemotherapeutic agents, immunomodulatory drugs, vascular endothelial growth factor pathway inhibitors, tyrosine kinase inhibitors, and radiotherapy, impart increased risk for ATEs that result from specific therapy-related mechanisms, often involving endothelial injury. Cancer cell-specific prothrombotic properties are important players in the pathogenesis of cancer-associated hypercoagulability. There are distinct biological and molecular processes preferentially activated in specific cancer cells which can trigger ATEs, including platelet activation, increased expression of procoagulants and suppression of fibrinolytic activity. ATEs portend adverse prognosis in cancer patients. Prevention and treatment of cancer-associated ATEs may be improved by greater awareness and careful monitoring for vascular toxicity, aggressive effort to optimize conventional cardiovascular risk factors, and use of antiplatelet and antithrombotic agents in selected patients. These issues are targets for future studies aimed to reduce ATEs in patients with cancer., (Copyright © 2018. Published by Elsevier Ltd.)

Activated proteins of the coagulation system are known to enhance angiogenesis and tumor growth. Notably, the main coagulation proteins involved are those of the extrinsic and common pathways. Strategies to attenuate tumor progression by decreasing activation of the coagulation system may be compromised by an increased risk of bleeding. Currently, studies using derivatives of heparins devoid of or with low anticoagulant activity are being conducted. Heparanase protein was demonstrated to enhance tissue factor activity. In-house developed peptides, deriving from tissue factor pathway inhibitor 2 (TFPI-2) were shown to inhibit heparanase procoagulant activity by interrupting the interaction between TF and heparanase. These peptides appeared to have a non-hemostatic anti-angiogenic effect. In a mouse model, the peptides caused a significant reduction in tumor growth and relapse, without predisposing to bleeding. Hence, the effects of these inhibitory peptides in cancer patients may deserve further investigation in clinical research studies., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In fetal/neonatal alloimmune thrombocytopenia (FNAIT), platelets are destroyed by maternal antibodies directed against fetal/neonate antigens. Thrombocytopenia can be severe and lead to intracranial hemorrhage (ICH) in about 10% of cases. Although three types of antigen groups, presented on platelets [ABO blood group antigens, human leukocyte antigens (HLA) and human platelet antigens (HPA)] are known to be implicated in immune platelet destruction, antibodies against HPA are most commonly involved in FNAIT and hence are the target of extensive research. Awareness of FNAIT by physicians as well as the availability of the most sensitive diagnostic methods capable of detecting a wide range of antibodies are crucial for the diagnosis of FNAIT and the prevention of severe thrombocytopenia and its bleeding risks in subsequent pregnancies., (© 2017 Elsevier Ltd. All rights reserved.)

Venous thromboembolism (VTE) is a major common complication in cancer patients. Risk-adapted thromboprophylaxis and antithrombotic therapy for patients diagnosed with VTE can reduce the recurrence of VTE events. Thrombotic risk varies according to cancer type, stage, and comorbidities. The current review analyzes most recent data and provides clinical guidance for the management of women with cancer-associated thrombosis., (© 2017 Elsevier Ltd. All rights reserved.)

Background: In patients with venous thromboembolism (VTE) and factor V Leiden (FVL) or prothrombin 20210G-A mutation (PTM), the influence of gender on outcome has not been consistently studied., Methods: We used the RIETE (Registro Informatizado Enfermedad TromboEmbolica) database to assess the existence of gender differences in the rate of VTE recurrences (deep vein thrombosis [DVT] or pulmonary embolism [PE]) or major bleeding during the course of anticoagulation and after its discontinuation in FVL and PTM carriers., Results: From March 2001 to September 2016, 11,224 VTE patients underwent thrombophilia testing. Of these, 1,563 were FVL carriers (863 men and 700 women) and 1,231 were PTM carriers (659 men and 572 women). During the course of anticoagulant therapy, men with FVL had a 6-fold higher rate of VTE recurrences than major bleeds (31 vs. 5 events). In women with FVL, the rate of VTE recurrences was 2-fold higher (16 vs. 8), as was in men (17 vs. 8) or women (17 vs. 9) with PTM. After discontinuing anticoagulation, men with FVL had a 3-fold higher rate of DVT recurrences than women (hazard ratio [HR]: 3.13; 95% CI: 1.79-5.67), with no differences in PE recurrences. Among patients with PTM, there were no gender differences in the rate of DVT (HR: 1.89; 95% CI: 1.00-3.65) or PE recurrences (HR: 1.82; 95% CI: 0.83-4.12)., Conclusions: During the anticoagulation course, men with FVL are at a much higher risk for VTE recurrences than bleeding. After discontinuing anticoagulation, men with FVL are at an increased risk for DVT recurrences., (© 2017 Elsevier Ltd. All rights reserved.)

Introduction: The blood supply of the bone and bone marrow are interconnected through a network of vessels. Arteries penetrating the bone flow into the marrow cavity while blood from marrow sinuses and veins leave the tissue via the bone., Aim: The current study was designed to search for thrombosis in the small blood vessels of bone and bone marrow., Materials and Methods: Bone biopsies of 40 patients were studied using specific staining to fibrin with martin scarlet blue (MSB) and by immune-staining to tissue factor (TF), TF pathway inhibitor and heparanase that is a pro-angiogenic and pro-coagulant protein. Biopsies included: ten cases of bone metastasis from carcinoma origin, ten cases of avascular necrosis (AVN) of femur head and ten cases of osteoarthrosis of femur head. Ten cases with diffuse large cell lymphoma without bone or bone marrow involvement were the control group., Results: Vessels density was higher in the bone and bone marrow of metastasis, AVN and osteoarthrosis biopsies compared to controls (P<0.001). Thrombi were documented in the bone and bone marrow of metastasis (5/10), AVN (6/10) and osteoarthrosis (6/10) biopsies and were absent in the controls. Staining of TF, TFPI and heparanase were more prominent, mainly in the blood vessels, in the biopsies of metastasis, AVN and osteoarthrosis compared to controls., Conclusions: The present study demonstrates for the first time thrombosis in the microcirculation of bone and bone marrow that can potentially contribute to patients bone pain. Increased level of TF and heparanase may contribute to the procoagulant and pro-angiogenic state. Intervention with anticoagulant drugs to prevent bone pain should be further evaluated., (© 2016 Elsevier Ltd. All rights reserved.)

Introduction: Acute myeloid leukemia (AML) is characterized by rapid growth of leukemic blast cells. Extracellular vesicles (EVs) are shed from normal and pathologic cells and express membrane proteins and antigens, reflecting their cellular origin., Aim: To explore whether bone marrow EVs of AML patients originate from blast cells and are capable of influencing hematopoietic stem cells (HSC) in a pseudo-natural microenvironment obtained by co-culture of HSC with mesenchymal stem cells (MSC)., Materials and Methods: Bone marrow (BM) samples were collected from healthy controls and patients with newly diagnosed AML at three time points: diagnosis, nadir and remission. EV concentration, cell origin and expression of coagulation proteins were characterized by FACS. Stem cells were obtained from Ficoll gradient of cord blood (CB) followed by CD34+ isolation. Cord blood stem cells with or without MSC were co-incubated with AML EVs. EV internalization was demonstrated by FACS-AMNIS and confocal microscopy. Mir-125b and -155 expressions in the cells were analyzed by RT-PCR., Results: AML patients were enrolled in the study. The total BM-EVs number was higher in patients at first remission compared to controls, while blast EV counts (labeled with anti-CD34, CD33, CD117) were higher in patients at diagnosis compared to controls and to patients in remission. Internalization of CD117+/CD33+ BM-EVs to cord blood stem cells in the presence or absence of MSC was evaluated by FACS-AMNIS. Confocal microscopy of CD33+ stained EVs strengthens the findings and shows presence of EVs even in the cytoplasm and the nucleus. Quantitative analysis of mir-125b and mir-155 expression in cord blood stem cells incubated with AML EVs revealed a clear tendency of increased expression in case of cell exposure to AML EVs in comparison to healthy control EVs. This tendency was emphasized in the presence of MSC., Conclusions: EVs of AML patients are generated from blast cells. By internalization into naïve stem cells they can influence their differentiation. Moreover, the presence of mesenchymal stem cells is likely to be essential to the process., (© 2016 Elsevier Ltd. All rights reserved.)

Heparanase is an endo-β-D-glucuronidase that is capable of cleaving heparan sulfate side chains of heparan sulfate proteoglycans on cell surfaces and the extracellular matrix. This activity is strongly implicated in tumor metastasis and angiogenesis. We have earlier demonstrated that apart of its well characterized enzymatic activity, heparanase may also affect the hemostatic system in a non-enzymatic manner. We showed that heparanase up-regulated the expression of the blood coagulation initiator-tissue factor (TF) and interacted with the tissue factor pathway inhibitor (TFPI) on the cell surface membrane of endothelial and tumor cells, leading to dissociation of TFPI and resulting in increased cell surface coagulation activity. Moreover, we demonstrated that heparanase directly enhanced TF activity, which led to increased factor Xa production and subsequent activation of the coagulation system. In patients with cancer, increased heparanase procoagulant activity appeared to be a potential predictor of survival. We have also shown that JAK-2 is involved in heparanase up-regulation via the erythropoietin receptor, a finding that may point to a new mechanism of thrombosis in JAK-2 positive patents with essential thrombocytosis. Recently, we found that the solvent accessible surface of TFPI-2 first Kunitz domain had a role in TF/heparanase complex inhibition. Peptides derived from TFPI-2 inhibitory site were shown to reduce coagulation activation induced by heparanase and to attenuate sepsis severity and tumor growth in a mouse model, without predisposing to significant bleeding tendency. These data imply that inhibition of heparanase procoagulant domain is potentially a good target for sepsis and cancer therapy., (© 2016 Elsevier Ltd. All rights reserved.)

Background: Trans-metatarsal operation to diabetic foot necrosis is a common procedure although only half of the patients do not need a second amputation due to surgery wound ischemia. No current tools are available for early prediction of surgery success and the clinical decision for a second operation may take weeks. Heparanase protein is involved in inflammation, angiogenesis and coagulation activation. The aim of the study was to evaluate heparanase level and procoagulant activity as an early predictor for success or failure of diabetic foot trans-metatarsal surgery., Methods: The study group included 40 patients with diabetic foot necrosis requiring trans-metatarsal surgical intervention. Eighteen patients designated as necrotic group, developed post-surgery necrosis at the surgery wound within the first month, requiring a second more proximal amputation. Skin biopsies from the proximal surgery edge were stained for heparanase, tissue factor (TF), TF pathway inhibitor (TFPI) and by hematoxylin and eosin. Plasma samples were drawn pre-surgery and at 1h, 1week and 1month post-surgery. Samples were tested for heparanase levels by ELISA and TF+heparanase activity, TF activity and heparanase procoagulant activity., Results: Skin biopsy staining did not predict subsequent necrosis. In the non-necrotic group a significant rise in TF+heparanase activity, heparanase activity and heparanase levels were observed 1h and 1week post-surgery. The most significant increase was in heparanase procoagulant activity at the time point of 1h post-surgery (P<0.0001). Pre-surgery TF activity was significantly lower in the non-necrotic group compared to the necrotic group (P<0.05)., Conclusions: Measuring heparanase procoagulant activity pre-surgery and 1h post-surgery could potentially serve as an early tool to predict the procedure success. The present results broaden our understanding regarding early involvement of heparanase in the wound healing process., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Introduction: Microvesicles including exosomes and microparticles, participate in the placental-maternal crosstalk in normal pregnancies and gestational vascular complications (GVC). Low molecular weight heparin (LMWH) is known to reduce the risk of placenta-mediated pregnancy complications. This study was aimed to characterize microvesicles of pregnant women receiving LMWH and explore microvesicle involvement in trophoblast and endothelial cell function., Materials and Methods: Microvesicles were isolated from blood samples obtained from non-pregnant women, healthy pregnant women (HP) and pregnant woman treated with LMWH. Microvesicle protein contents were assessed by protein array and ELISA. Microvesicle effects on early stage trophoblasts, term trophoblasts and endothelial cell migration, angiogenesis and apoptosis were evaluated., Results: Microvesicles derived from the group treated with LMWH contained higher levels of several proangiogenic proteins compared to those of HP women. Exposure of endothelial cells to circulating microvesicles derived from HP and LMWH treated groups induced significantly higher cell migration and branch tube formation compared to untreated cells. The effect of microvesicles from HP- and LMWH groups on early-stage trophoblast migration was similar. Microvesicles derived from these two study groups significantly decreased early-stage trophoblast apoptosis, while microvesicles derived from the HP-group (but not from the LMWH-group) significantly increased the term trophoblast apoptosis (TUNEL assay) compared to untreated cells., Conclusion: Therapy with LMWH affects patients' microvesicle content, leading to normalization of invasion, angiogenesis activity and survival of endothelial and trophoblast cells in vitro. The effects of LMWH on microvesicles may point to an additional mechanism of heparin action in high-risk pregnancy., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Inflammation and coagulation are known to affect each other in many ways. Vasculitis represents a group of disorders where blood vessels (small, medium, large or variable) are infiltrated with inflammatory cells. Accumulating evidence in the literature suggests both clinical and physiological association between vasculitis and thrombosis. Vasculitis-associated thrombosis involves arteries and veins, and a tight connection has been reported between the activity of vasculitis and the appearance of thrombosis. Pathophysiology of these relations is complex and not completely understood. While thrombophilic factors are associated with vasculitis, it remains unclear whether a true association with clinical thrombosis is present. Furthermore, several factors leading to hemostasis, endothelial injury and induction of microparticles were described as possibly accounting for thrombosis. Management of thrombosis in vasculitis patients is challenging and should be further assessed in randomized controlled studies. The current review describes clinical manifestations, pathogenesis and management of thrombosis associated with different vasculitides., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Extracellular membrane vesicles (EVs) also termed microvesicles (MVs) are secreted from different cells, are present in the blood circulation under normal physiological conditions, and their levels increase in a wide range of disease states. EVs contain proteins, growth and apoptotic factors, DNA fragments, microRNAs as well as messenger RNAs (mRNAs); therefore, they may function as regulators in cell-cell communication and mediators of cell signaling during multiple biological processes. The current review focuses on the role of EVs in healthy pregnancy and gestational vascular complications and discusses the involvement of EVs in gene regulation, placental hemostasis and cell function that overall reflect the placental-maternal crosstalk., (© 2015 Elsevier Ltd. All rights reserved.)

Gaucher disease (GD) is a lysosomal disorder caused by inherited deficiency of glucocerebrosidase, resulting in the accumulation of glucocerebroside in macrophages, termed "Gaucher cells" (GCs), leading to multiorgan involvement, with hepatosplenomegaly, cytopenias, pulmonary hypertension and osseous complications. The characteristic feature of GD is the organ GCs infiltration compromising their function by inducing local inflammation, infarcts and fibrosis. Enzyme replacement therapy (ERT) available for over two decades improves hematological abnormalities, reverses the visceromegaly, ameliorates bone symptoms and prevents further skeletal complications. GD affects most female events during the reproductive age, particularly, fertility, pregnancy, delivery and puerperium. While pregnancy in GD may exacerbate disease manifestations, the disease may have deleterious effect on female reproductive health milestones. ERT has a beneficial effect on the pregnancy outcome in terms of the risk of spontaneous abortion and GD-related complications, particularly bleeding during delivery and postpartum. Treatment approaches and management aspects of reproductive age events are reviewed hereby, with a focus on the outcome improvement of pregnancies, deliveries and postpartum period in GD patients., (© 2015 Elsevier Ltd. All rights reserved.)

The brain and the placenta synthesize identical peptides and proteins, such as brain-derived neurotrophic factor, oxytocin, vascular endothelial growth factor, cortisol, and matrix metalloproteinases. Given the promiscuity between neurochemistry and the mechanism of placentation, it would be expected that mental disorders occurring during pregnancy would increase the risk of adverse obstetric and neonatal outcomes. Indeed, expectant mothers with anxiety disorders, post-traumatic stress disorder, schizophrenia, or depressive disorders are at higher risk of preterm birth, low-birth-weight and small-for-gestational-age infants than controls. These mental illnesses are accompanied by a procoagulant phenotype and low activity of tissue plasminogen activator, which may contribute to placental insufficiency. Another risk factor for pregnancy complications is hyperemesis gravidarum, more common among women with eating disorders or anxiety disorders than in controls. Severe hyperemesis gravidarum is associated with dehydration, electrolyte imbalance and malnutrition, all of which may increase the risk of miscarriages, of low-birth-weight babies and preterm birth. This paper reviews some aspects of mental disorders that may influence pregnancy and neonatal outcomes., (© 2015 Elsevier Ltd. All rights reserved.)

Background: Heparanase is implicated in angiogenesis and tumor progression. We had earlier demonstrated that heparanase may also affect the hemostatic system in a non-enzymatic manner. It forms a complex and enhances the activity of the blood coagulation initiator- tissue factor (TF). Although increased heparanase antigen level in the plasma and biopsies of cancer patients was previously demonstrated, in the present study we evaluated, for the first time, the heparanase procoagulant activity in the plasma of patients with lung cancer., Materials and Methods: Sixty five patients with non-small cell lung cancer at presentation and twenty controls were recruited. Plasma was studied for TF / heparanase procoagulant activity, TF activity and heparanase procoagulant activity using chromogenic assay and heparanase antigen levels by ELISA., Results: Heparanase antigen levels were higher in the study group compared to control (P=0.05). TF / heparanase activity, and even more apparent, heparanase procoagulant activity were significantly higher in the study group compared to controls (P=0.008, P<0.0001, respectively). No significant difference was observed in the TF activity between the groups. Survival of patients with heparanase procoagulant activity higher than 31 ng/ml predicted a mean survival of 9 ± 1.3 months while heparanase procoagulant activity of 31 ng/ml or lower predicted a mean survival of 24 ± 4 months (P=0.001). Heparanase procoagulant activity was higher than 31 ng/ml in the four cases of thrombosis detected during the follow-up period., Conclusions: Elevated heparanase procoagulant activity in patients with lung cancer reveals a new mechanism of coagulation system activation in malignancy. Heparanase procoagulant activity can potentially be used as a predictor for survival., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The BCR-ABL1 negative myeloproliferative neoplasms (MPNs) are associated with an increased risk of both venous and arterial thromboembolic events. Thromboses may be the presenting clinical feature of an MPN or may occur during the course of the disease. Treatment comprises anticoagulant and antiaggregant agents as in non- MPN thromboses, and treatment of the particular MPN. The duration of anticoagulant treatment that is required for MPN thrombosis is unknown. This study was performed to survey the opinion of hematologists who treat patients with MPN regarding the duration of anticoagulation or antiaggregant therapy in patients in whom thrombosis is the presenting feature of MPN. Five clinical scenarios in which thromboembolism (cerebral vein thrombosis, pulmonary embolism, cerebrovascular accident, splanchnic vein thrombosis, portal vein thrombosis) was a presenting feature of MPN were created using a web-based tool and were sent by email to hematologists in Israel, Italy and England and to hematologists identified as key opinion leaders in the field of MPN. Physicians were asked to recommend duration of anticoagulation and/or aspirin use choosing from 4 alternatives provided. Seventy-three physicians responded to the survey. 42 physicians considered MPNs to be their main area of clinical interest, and 31 did not. 21 physicians saw more than 20 MPN patients per week, and 50 physicians had been in hematology practice for more than 10years. Responses regarding the duration of anticoagulation and/or the use of aspirin varied for all of the clinical vignettes. Neither physician area-of-interest, volume of MPN patients treated nor years in practice were related to the responses obtained. This study demonstrates that hematologists, including those specializing in MPNs, lack consensus in their approach to the long-term treatment of thromboses as the presenting feature of an MPN. Controlled clinical studies are needed to inform appropriate decision making in this area., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The serotonin transporter (SERT) is found in neuron and platelet membranes. Selective serotonin-reuptake inhibitors (SSRIs) are widely prescribed for severe depression. They may at least partly counteract the effects of serotonin on the vascular biology system, can lower agonists-induced platelet activation, aggregation and procoagulant activity in vitro, thus modulating platelet thrombogenicity. Other effects, such as those mediated through PAI-1 modulation, may indirectly influence neurobiology-relevant mechanisms involved in depression. Patients receiving SSRIs are at increased bleeding risk and decreased risk of arterial occlusive events, such as myocardial infarction, compared to those using non-SSRI antidepressants. The objectives of this review were to highlight antiplatelet and profibrinolytic properties of SSRIs and discuss the potential role of these activities in the context of SSRI brain effects., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Heparanase is an endo-β-D-glucuronidase that is capable of cleaving heparan sulfate side chains of heparan sulfate proteoglycans on cell surfaces and the extracellular matrix, activity that is strongly implicated in tumor metastasis and angiogenesis. Apart of its well characterized enzymatic activity, heparanase was noted to exert also enzymatic-independent functions. Among these are the up-regulation of vascular endothelial growth factor (VEGF)-A, VEGF-C and activation of intra-cellular signaling involved in cell survival and proliferation. We had earlier demonstrated that heparanase may also affect the hemostatic system in a non-enzymatic manner. We had shown that heparanase up-regulated the expression of the blood coagulation initiator- tissue factor (TF) and interacted with the tissue factor pathway inhibitor (TFPI) on the cell surface membrane of endothelial and tumor cells, leading to dissociation of TFPI and resulting in increased cell surface coagulation activity. Moreover, we have demonstrated that heparanase directly enhanced TF activity which led to increased factor Xa production and subsequent activation of the coagulation system. Taking into account the prometastatic, pro-angiogenic and pro-coagulant functions of heparanase, over-expression in human malignancies and abundance in platelets, implies that heparanase is potentially a good target for cancer therapy., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Introduction: Hypercoagulation was suggested to be involved in preterm birth etiology; however, the coagulation state of preterm parturients remains unelucidated. The study aim was to evaluate the haemostatic system of pregnant women with premature uterine contractions (PUC)., Materials and Methods: The cohort study population consisted of 76 healthy pregnant women admitted with regular PUC. The study group included 38 women who experienced preterm birth; 14 of them had preterm premature rupture of membranes (PPROM). The control group included 38 women who eventually had term delivery. Groups were matched for maternal age, number of births and gestational age at admission. Blood samples were tested for haemostatic parameters and coagulation activation markers., Results: Significantly shorter PT and aPTT were documented in the study compared to control group (25.7±2 vs. 27.4±2.7seconds, P=0.003, and 9.96±0.5 vs. 10.1±0.4seconds, P=0.05, respectively), although differences in absolute values were small. There was no significant difference between the two groups in levels of: fibrinogen, D-dimer, protein C-global, free protein S antigen, factor VIII activity, Von Willebrand factor, plasminogen activator inhibitor-1, prothrombin fragments F1+2 (PT F1+2), tissue factor and tissue factor pathway inhibitor. Women with PPROM had significantly lower PT F1+2 levels compared to those who had preterm delivery with intact membranes (351±99 vs. 561±242pmol/L, P=0.003)., Conclusions: Shortened PT and aPTT, reflecting increased thrombotic activity in maternal plasma, could serve as a marker of real preterm labor in women with premature uterine contractions. Further prospective studies in a larger cohort are warranted to validate these findings., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Myeloproliferative neoplasms (MPNs) are generally considered to be diseases of elderly population; however, 20% of subjects diagnosed with ET are younger than 40 years. Increase in gestational age in the Western world and improved diagnostic tools raise MPN incidence during pregnancy. MPNs are associated with a remarkable risk for thrombosis and the hypercoagulability milieu associated with pregnancy increases that risk even further. Pregnancies of women diagnosed with MPNs may be complicated with placental thrombosis, fetal growth restriction or loss, and increased risk for maternal thrombosis. The live birth rate in ET and PV is as low as 60 %, with first-trimester loss occurring in 20-30% of pregnancies and an increase in late placenta-mediated complications. Major maternal complications (thromboembolic events and bleeding) are more frequent in PV compared with ET. Therapeutic options range from no therapy, aspirin alone, low-molecular weight heparin (LMWH) to cytoreductive therapy, tailored according to patient-specific risk factors., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Idiopathic avascular necrosis (AVN) of bone causes significant morbidity in adults although the pathophysiology is unknown. The present treatment options include systemic biphosphonate therapy and local bone drilling decompression, ameliorating the healing process and their by render the weight bearing femur head less vulnerable to collapse. In the present study we demonstrate the involvement of heparanase in AVN and in the acceptable treatments., Methods: 56 female rats were studied. In 8 control rats AVN was induced by ligamentum teres ligation of the right femur while the left femur remained intact. In the rest of the rats, in addition to right femur AVN, treatment was added by subcutaneous biphosphonate therapy, femoral head drilling or combination of the treatments. All rats were scarified after 6weeks. Immunostaining of the femur heads were performed to heparanase, tissue factor pathway inhibitor (TFPI), tissue factor (TF) and hematoxylin-eosin., Results: Staining of heparanase, TFPI and TF were most prominent in the bone-marrow tissue of the femur heads. Staining by hematoxylin-eosin revealed damaged femur heads with prominent heparanase and TFPI staining in the femur with AVN compared to the contra lateral side of the same rat. No difference was found in the TF staining between the two sides. In the drilling and / or biphosphonate therapy groups, in contrast to the control group, femur heads were preserved with no significant difference in heparanase and TFPI staining between the two sides., Conclusions: Heparanase and TFPI are locally elevated in the process of AVN and are normalized by the acceptable treatments. Inhibition of heparanase by heparins can potentially improve the nowadays therapy modalities., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Microparticles (MPs), sub-micron membrane vesicles, participate in the placental and maternal crosstalk in normal pregnancies as well as in gestational vascular complications (GVC). The article will review the effects of MPs on placental physiological processes, including hemostasis, trophoblast migration, invasion, placental vasculature and their involvement in pathologic states such as thrombosis, inflammation and endothelial dysfunction, resulting in GVC., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Orthopedic hip and knee surgeries are followed by a hypercoagulable state. Heparanase is implicated in inflammation, coagulation activation and angiogenesis. Recently, heparanase was shown to directly interact with tissue factor (TF) and to enhance the generation of factor Xa (Nadir et al., Haematologica, 2010). In addition, an assay assessing heparanase procoagulant activity has been lately developed (Nadir et al., Thromb Res, 2011). In the present study heparanase level and procoagulant activity in patients undergoing orthopedic surgery were assessed., Methods: The study group included 50 orthopedic patients. 31 patients underwent hip surgery and 19 had knee operation. 15 individuals suffered from traumatic hip fractures and 35 had osteoarthrosis of hip or knee joints. All patients received prophylactic dose of enoxaparin starting 6-8 hours post operation and lasting for 5 weeks. Plasma samples were drawn preoperatively and at 1 hour, 1 week and 1 month post operation. Samples were tested for heparanase levels by ELISA and TF/heparanase complex activity, TF activity, heparanase procoagulant activity, factor Xa and thrombin levels using chromogenic substrates., Results: Heparanase levels were significantly higher 1 hour and 1 week post operatively compared to preoperative levels (p<0.05, p<0.005, respectively). The most dramatic changes were observed in heparanase procoagulant activity reaching a 2 fold increase 1 week postoperatively and 1.7 fold increase 1month after surgery (p<0.0001, p<0.0001, respectively). Levels of factor Xa and thrombin did not significantly change., Conclusions: Heparanase is involved in coagulation activation of orthopedic surgery patients. Heparanase procoagulant activity is highest 1 week postoperatively and remains high 1month after operation. Considering extending prophylactic anticoagulant therapy or evaluating heparanase procoagulant activity may potentially prevent late thrombotic events., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Heparanase that was cloned from and is abundant in the placenta is implicated in cell invasion, tumor metastasis and angiogenesis. We have recently demonstrated that heparanase may also affect the hemostatic system in a non-enzymatic manner. Heparanase was shown to up-regulate tissue factor (TF) expression and interact with tissue factor pathway inhibitor (TFPI) on cell surface, leading to dissociation of TFPI from cell membrane of endothelial and tumor cells, resulting in increased cell surface coagulation activity. We have lately shown that heparanase directly enhances TF activity resulting in increased factor Xa production and activation of the coagulation system. Data indicate increased plasma levels of heparanase suggesting its possible involvement in pregnancy vascular complications. Elevation in heparanase levels and procoagulant activity was also documented in orthopedic surgery patients receiving prophylactic doses of enoxaparin. Taking into account the pro-metastatic and pro-angiogenic functions of heparanase, with over-expression in human malignancies and abundance in platelets and placenta, its involvement in the coagulation machinery is an intriguing novel platform for further research., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The diagnosis of cancer during pregnancy or in the post-partum period poses a major burden on the woman and her family. Issues of fetal and neonatal wellbeing are intricate, while mother's health is of primary concern., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Introduction: Amniotic fluid (AF) is an important medium for fetal development which exhibits high procoagulant activities; however, the role of these procoagulants during pregnancy has not been elucidated and might be associated with pregnancy complications. The current study aimed to evaluate factor X (FX) activation and its association with tissue factor (TF), tissue factor pathway inhibitor (TFPI) and coagulation activation markers in AF during normal human pregnancy., Methods: Activation of FX and concentration of TF, free TFPI, D-dimer and prothrombin fragments (F1+2) were evaluated in AF samples obtained for chromosome analysis from 91 women with normal pregnancy: 65 samples were taken from patients at 16-20 weeks of gestation, 9 samples were drawn at 21-30 weeks and 17 samples--after 30 weeks of gestation., Results: Activation of FX in AF significantly increased during normal pregnancy (from 65±41 to 205±80 equivalent RVV ng/mg total protein, P<0.0001). TF and TFPI levels in AF also rose with gestational age. In contrast, the AF concentration of D-dimer and F1+2, markers of coagulation activation significantly decreased when expressed per mg total protein. Levels of free TFPI correlated with TF (r=0.5, P<0.001), and were 8-fold higher than those of TF during pregnancy., Conclusion: High levels of TFPI might be associated with the inhibition of procoagulant activity in amniotic fluid during normal pregnancy, which may account for the rarity of clinical amniotic fluid embolism., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Heparanase that was cloned from and is abundant in the placenta is implicated in cell invasion, tumor metastasis and angiogenesis. Recently, we demonstrated that heparanase is directly involved in the regulation of the hemostatic system. Heparanase was shown to form a complex and enhance tissue factor (TF) activity, resulting in increased factor Xa production (Nadir et al. Haematologica, 2010). The present work suggests a novel assay to evaluate heparanase procoagulant activity., Methods: Heparanase procoagulant activity was studied using purified proteins of heparanase, TF, factor VIIa and factor X. The assay was verified in 55 plasma samples and compared to heparanase and tissue factor pathway inhibitor (TFPI) levels by ELISA and factor Xa, thrombin levels and antithrombin activity by chromogenic substrates. Thirty five samples were of third-trimester pregnant women (weeks 36-41) who were in labor or came for appointed elective cesarean section and 20 control samples were of non-pregnant healthy women., Results: Heparanase procoagulant activity assay was shown to differentiate heparanase procoagulant effect from TF activity, in purified proteins. Heparanase procoagulant activity was significantly higher in the plasma of pregnant women compared to non-pregnant (p < 0.005). Heparanase relative contribution to the TF / heparanase complex activity was significantly higher in the plasma of pregnant women compared to non-pregnant (29% increase, p < 0.0001). Differences in heparanase procoagulant activity were more prominent than changes in heparanase levels by ELISA, TF activity, factor Xa, thrombin and free TFPI levels., Conclusions: Heparanase procoagulant activity can be determined by the suggested assay. The assay revealed a significant contribution of heparanase to the procoagulant state in late third-trimester pregnancy and at delivery., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Microparticles (MPs) are shed from cell membranes of a variety of cells, promote thrombus formation, mediate pro-inflammatory effects and may cause endothelial dysfunction. Normal pregnancy is characterized by increased levels of MPs compared to non-pregnant healthy women but the prevalence, cell origin and the role of MPs in pregnancy-related complications remain controversial. Normal pregnancy is an acquired hyper-coagulable state due to an increase in procoagulants and decrease in natural anticoagulants. Pregnancy-related complications such as preeclampsia, intrauterine fetal growth restriction (IUGR) and fetal loss are associated with placental dysfunction and may cause significant maternal and fetal morbidity and mortality. This article highlights the role of microparticles in maternal placental crosstalk and the interplay between microparticles, thrombosis and pregnancy complications., (© 2011 Elsevier Ltd. All rights reserved.)

Background: Heparanase is an endo-β-D-glucuronidase dominantly involved in cell invasion, tumor angiogenesis and metastasis. Recently, we demonstrated increased levels of heparanase, tissue factor pathway inhibitor (TFPI)-2 and vascular endothelial growth factor (VEGF)-A in early miscarriages (Nadir et al., Thromb Res, 2010). Herein, we investigated the role of heparanase in third trimester placentas, in correlation to tissue factor (TF), TFPI, TFPI-2, and VEGF-A., Methods: Twenty five third-trimester placenta samples (weeks 36-41) were studied applying real time RTPCR and immunostaining. Ten cases were placentas of elective cesarean sections, 8 cases were of normal vaginal deliveries and 7 samples were placentas of intra-uterine growth restriction (IUGR) fetuses. Skin and lung tissues of heparanase over-expressing mice and heparanase knock-out mice were subjected to immunostaining., Results: Sections obtained from vaginal and IUGR placentas revealed 2 folds increased levels of heparanase, TFPI-2 and VEGF-A compared to placentas from elective cesarean sections in maternal decidua as well as in fetal placenta elements. Interestingly, abundance of TFPI staining in the intra-villous blood was observed in placentas of vaginal and IUGR deliveries. Heparanase effect on TFPI release to the blood was supported by immunostaining of heparanase over-expressing and heparanase knock-out mice tissues., Conclusions: In regard to our previous data on early pregnancy losses, the present data strengthen the understanding that in placental vascular complications levels of heparanase, TFPI-2 and VEGF-A increase. In the process of delivery, heparanase may have a regulatory role on TFPI release to fetal circulation., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

There is a lack of information on clinical risk factors for venous thromboembolism (VTE) development following prolonged traveling. Clinical characteristics and additional risk factors for VTE in travelers were analyzed in RIETE, an ongoing registry of patients with symptomatic, confirmed acute VTE. Of 26,172 patients enrolled in RIETE as of May 2009, 2% developed VTE in association with recent traveling. Travelers were ten years younger, had significantly more previous VTE events (20% vs. 16%; OR: 1.4; 95%CI: 1.1-1.7) and their body mass index (BMI) was 28.4±5.1 vs. 27.7±5.2 in other patients from the registry (P=0.004). 115 (20%) of recent travelers had previous VTE compared to 16% among others patients (OR: 1.4; 95%CI: 1.1-1.7). Recent travelers used hormones significantly more frequently (8.7% vs. 3.7%; OR: 2.5; 95% CI: 1.8-3.3) and more often had a positive thrombophilia test (16% vs. 8.7%; OR: 2; 95%CI: 1.6-2.6). Travelers used LMWH prophylaxis significantly less frequently than other patients in the registry (2.4% vs. 13%; OR 0.2; 95%CI: 0.1-0.3). There were differences in VTE risk in professional drivers compared to passengers. The current study demonstrates four risk factors for VTE development after long traveling: high BMI, previous VTE, hormone use and thrombophilia. Studies of prophylactic antithrombotic therapy in high risk travelers are warranted., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Introduction: Type 2 diabetes mellitus (DM) patients with coronary artery disease (CAD) have elevated plasma oxidized-LDL (OxLDL) levels and impaired neovascularization. Hyperglycemia and hyperlipidemia impair endothelial progenitor cell (EPC) migration, and endothelial nitric oxide (NO) bioavailability and NO synthase (NOS) activity are essential for EPC migration. Stromal-derived factor-1alpha (SDF1alpha) contributes to EPC mobilization and homing by stimulating the CXC receptor-4 (CXCR4) on the EPC plasmalemma to activate the Pi3K/Akt/eNOS signaling pathway. Therefore, we investigated the effect of high glucose (HG) and OxLDL on the migration and NO bioavailability of EPCs from healthy individuals, and then correlated the findings with those of EPCs from type 2 DM patients with and without CAD., Materials and Methods: EPCs from 15 healthy and 55 patients were exposed to HG, OxLDL, or both before evaluating EPC count, migration and NO production, and expression of CXCR4 and members of Pi3K/Akt/eNOS signaling cascade., Results: Counts, migration, CXCR4 expression, and NO production were significantly reduced in EPCs from DM and CAD patients compared with that obtained in EPCs from healthy, and were further reduced in DM patients with CAD. The expression of CXCR4 and activation of Pi3K/Akt/eNOS signaling cascade were suppressed in OxLDL- and HG-treated EPCs, and this suppression was exacerbated when EPCs were treated simultaneously with HG and OxLDL., Conclusions: Hyperglycemia and elevated circulating OxLDL in DM patients with CAD severely impair EPC migration. These results suggest that the underlying mechanism for this impaired EPC migration is linked to the CXCR4/Pi3K/Akt/eNOS signaling pathway., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

Introduction: Thrombotic events (TE) are well documented in patients with acute lymphoblastic leukemia (ALL). They occur due to a combination of disease, host and treatment-related risk factors. Low molecular weight heparin (LMWH) has been found to be effective and safe in children with ALL during L-asparaginase treatment. At present, whether or not to give primary anticoagulant prophylaxis for TE during induction or reinduction courses to children with ALL is controversial. Our group investigated the use of LMWH as a prophylactic treatment for ALL children with a genetic prothrombotic predisposition., Methods: Eighty consecutive children with ALL treated between the years 1999 and 2008 were studied. Genetic analysis of factor V Leiden (G1691A) and prothrombin (G20210A) gene mutations were done at diagnosis. LMWH was given once daily subcutaneously at a dose of 1mg/kg, starting with the first dose of L-asparaginase (day 12 of induction, day 8 of consolidation) until one week after the last dose (day 40 of induction, day 25 of consolidation), to patients with inherited thrombophilia stemming from either factor V Leiden or prothrombin gene mutation., Results: Eighteen patients were found to have a genetic predisposition for TE, all of them received prophylactic LMWH. Six of the 80 (7.5%) patients developed thromboembolic events. Three of these six had a prothrombin (PT) gene mutation and received prophylactic LMWH. No TE event occurred in patients with factor V Leiden mutation receiving prophylactic LMWH., Conclusion: It is suggested that patients with ALL and PT gene mutation may have a higher risk of clotting complications in comparison to patients with factor V Leiden mutation. A randomized trial of LMWH should be performed to assess its safety and efficacy in preventing venous TE., ((c) 2010 Elsevier Ltd. All rights reserved.)

Background: Heparanase cloned from and abundant in the placenta is implicated in cell invasion, tumor angiogenesis and metastasis. Recently, we demonstrated that heparanase is involved in the regulation of the hemostatic system. Heparanase was found to up-regulate tissue factor (TF) expression (Nadir et al., JTH, 2006) and interact with tissue factor pathway inhibitor (TFPI) on the cell surface, leading to dissociation of TFPI from the cell membrane resulting in increased cell surface coagulation activity (Nadir et al., TH, 2008). Herein, we investigated the role of heparanase in the placenta, focusing on its effect on TF, TFPI, TFPI-2, and vascular endothelial growth factor (VEGF)-A., Methods: Twenty formalin embedded placenta samples of abortions (weeks 6-10) were studied applying real time RT-PCR and immunostaining. Ten cases were miscarriages of women with thrombophilia and recurrent fetal losses, and ten control cases were pregnancy terminations. JAR (human choriocarcinoma trophoblasts) cells were transfected with full-length heparanase cDNA or incubated with active (50+8 kDa) recombinant heparanase and the effects on TF, TFPI, TFPI-2 and VEGF-A were examined using real time RT-PCR and immunoblotting., Results: Sections obtained from miscarriages revealed increased (2-3-folds) levels of heparanase, VEGF-A and TFPI-2 compared to placentas from controls in maternal as well as in fetal placenta elements. JAR cells overexpressing heparanase or incubated with exogenous recombinant heparanase exhibited a 2-3-fold increase in TFPI and TFPI-2 in cell lysates both at the protein and mRNA levels, with no detectable effect on VEGF-A and TF levels. Accumulation of TFPI and TFPI-2 in the cell culture medium was increased 4-6-folds, exceeding the observed induction of TFPI and TFPI-2 gene transcription., Conclusions: These results indicate a regulatory effect of heparanase on TFPI and TFPI-2 in trophoblasts, suggesting a potential involvement of heparanase in early miscarriages., (Copyright (c) 2009 Elsevier Ltd. All rights reserved.)

Heparanase is an endo-beta-D-glucuronidase capable of cleaving heparan sulfate (HS) side chains of heparan sulfate proteoglycans (HSPG) on cell surfaces and the extracellular matrix, activity that is strongly implicated in tumor metastasis and angiogenesis. Evidence was provided that heparanase over-expression in cancer cells results in a marked increase in tissue factor (TF) levels. Likewise, TF was induced by exogenous addition of recombinant heparanase to tumor cells and primary endothelial cells, induction that was mediated by p38 phosphorylation and correlated with enhanced procoagulant activity. TF induction was further confirmed in heparanase over-expressing transgenic mice and correlated with heparanase expression levels in leukemia patients. Heparanase was also found to be involved in the regulation of tissue factor pathway inhibitor (TFPI). A physical interaction between heparanase and TFPI was demonstrated, suggesting a mechanism by which secreted heparanase interacts with TFPI on the cell surface, leading to dissociation of TFPI from the cell membrane and increased coagulation activity, thus further supporting the local pro-thrombotic function of heparanase. Data indicate a possible involvement of heparanase in early miscarriages and point to a regulatory effect on TFPI and TFPI-2 in trophoblasts. As heparins are strong inhibitor of heparanase, in view of the effect of heparanase on TF, the role of heparins anticoagulant-activity may potentially be expanded. Taking into account the pro-metastatic and pro-angiogenic functions of heparanase, its over-expression in human malignancies and abundance in platelets, its involvement in the coagulation machinery is an intriguing novel arena for further research.

Introduction: Various integrins are expressed on trophoblast membrane and participate in placenta anchoring, cell adhesion , migration and vascular development. Although integrin alpha IIb beta 3 is known to be associated mainly with megakaryocytes and platelets, here we show for the first time its presence in human trophoblasts and in ex-vivo placental villi., Methods: Trophoblasts were isolated and cultured from early term placentas (9-13 weeks of gestation). The presence of alpha IIb beta 3 integrin was demonstrated in the cells by means of immunofluorescence , flow cytometry and Western blot analysis and in villous placentas by immunohistochemistry. Interaction of trophoblasts with fibronectin and fibrin was evaluated by adhesion assays., Results: Expression of alpha IIb protein in trophoblasts decreased with time in culture and was more prominent when cells were cultured on fibrin as compared to fibronectin. Presence of alpha IIb on villous trophoblasts was documented in placenta sections of 8 and 15 weeks of gestation but not in term placentas. Trophoblasts adhesion to fibrin was reduced by 45% in the presence of blocking antibodies for alpha IIb, but only by 10% to fibronectin, suggesting fibrin as a ligand for trophoblast alpha IIb beta 3., Conclusions: Our finding demonstrate the transient presence and participation of alpha IIb beta 3 in the orchestrated adhesion molecules of trophblasts and villi. The increased adhesion and expression of alpha IIb in trophoblasts on fibrin suggest its involvement as a ligand in the extracellular milieu of the early fetal placenta., ((c) 2009 Elsevier Ltd. All rights reserved.)