[Expression and clinical significance of coagulate and fibrolysis factors in tissue and plasma from hepatocellular carcinoma patients]

BACKGROUND & OBJECTIVE

Considerable evidences showed that changes of coagulation and proteolysis factors are closely related to the genesis and growth of malignancy. This study was to detect the expression of tissue factor (TF), urokinase-type plasminogen activator (uPA), and urokinase-type plasminogen activator receptor (uPAR) in cancer tissues and plasma of patients with hepatocellular carcinoma (HCC), and analyze their prognostic significance.

METHODS

Blood samples were obtained from 50 HCC patients and 30 patients with non-tumor disease. Plasma levels of TF, uPA, and uPAR were detected by ELISA. Cancer tissue and adjacent tissue samples were obtained randomly from 27 patients in HCC group; normal liver tissue samples were also collected from 27 patients in benign disease group. The mRNA levels of TF, uPA, and uPAR in all tissue samples were detected by reverse transcription-polymerase chain reaction (RT-PCR). Their correlations to clinicopathologic features of HCC were analyzed.

RESULTS

Plasma levels of TF, uPA, and uPAR were significantly higher in HCC group than in control group [(409.4+/-13.0) pg/ml vs. (318.8+/-69.1) pg/ml, (1.63+/-0.52) ng/ml vs. (1.20+/-0.40) ng/ml, (1.36+/-1.00) ng/ml vs. (0.68+/-0.28) ng/ml, P<0.05]. Poor differentiation, larger size, and cirrhosis of HCC increased plasma TF level (P<0.05); cirrhosis also increased plasma uPA level (P<0.05); lymphatic metastasis, extrahepatic metastasis, and portal venous tumor thrombus (PVTT) increased plasma levels of TF, uPA, and uPAR (P<0.05). The positive rates of TF, uPA, and uPAR in HCC tissues were 62.96%, 70.37%, 77.78%, respectively; the mRNA levels of TF, uPA, and uPAR were 0.57+/-0.27, 0.96+/-0.46, 0.78+/-0.32, respectively. The positive rates and mRNA levels of TF, uPA, and uPAR were all significantly higher in HCC tissues than in adjacent tissues and normal liver tissues (P<0.05). Intrahepatic metastasis and PVTT increased the positive rate and mRNA levels of TF, uPA, and uPAR in HCC (P<0.05). Pearson test showed that TF expression was positively correlated to uPA, and uPAR expression (r=0.373, P<0.01; r=0.534, P<0.01); uPA expression was positively correlated to uPAR expression (r= 0.365, P<0.01). COX regression analyses showed that TF, uPA, and uPAR were independent prognostic factors of HCC (Chi(2)=6.05, P=0.014; Chi(2)=4.29, P=0.038; Chi(2)=4.40, P=0.036).

CONCLUSION

TF, uPA, uPAR might have synergetic effect in invasion and metastasis of HCC, and they might relate to prognosis.

Gypenoside XLIX, a naturally occurring gynosaponin, PPAR-alpha dependently inhibits LPS-induced tissue factor expression and activity in human THP-1 monocytic cells

Tissue factor (TF) is involved not only in the progression of atherosclerosis and other cardiovascular diseases, but is also associated with tumor growth, metastasis, and angiogenesis and hence may be an attractive target for directed cancer therapeutics. Gynostemma pentaphyllum (GP) is widely used in the treatment of various cardiovascular diseases including atherosclerosis, as well as cancers. Gypenoside (Gyp) XLIX, a dammarane-type glycoside, is one of the prominent components in GP. We have recently reported Gyp XLIX to be a potent peroxisome proliferator-activated receptor (PPAR)-alpha activator. Here we demonstrate that Gyp XLIX (0-300 microM) concentration dependently inhibited TF promoter activity after induction by the inflammatory stimulus lipopolysaccharide (LPS) in human monocytic THP-1 cells transfected with promoter reporter constructs pTF-LUC. Furthermore, Gyp XLIX inhibited LPS-induced TF mRNA and protein overexpression in THP-1 monocyte cells. Its inhibition of LPS-induced TF hyperactivity was further confirmed by chromogenic enzyme activity assay. The activities of Gyp XLIX reported in this study were similar to those of Wy-14643, a potent synthetic PPAR-alpha activator. Furthermore, the Gyp XLIX-induced inhibitory effect on TF luciferase activity was completely abolished in the presence of the PPAR-alpha selective antagonist MK-886. The present findings suggest that Gyp XLIX inhibits LPS-induced TF overexpression and enhancement of its activity in human THP-1 monocytic cells via PPAR-alpha-dependent pathways. The data provide new insights into the basis of the use of the traditional Chinese herbal medicine G. pentaphyllum for the treatment of cardiovascular and inflammatory diseases, as well as cancers.

Signal-dependent splicing of tissue factor pre-mRNA modulates the thrombogenicity of human platelets

Tissue factor (TF) is an essential cofactor for the activation of blood coagulation in vivo. We now report that quiescent human platelets express TF pre-mRNA and, in response to activation, splice this intronic-rich message into mature mRNA. Splicing of TF pre-mRNA is associated with increased TF protein expression, procoagulant activity, and accelerated formation of clots. Pre-mRNA splicing is controlled by Cdc2-like kinase (Clk)1, and interruption of Clk1 signaling prevents TF from accumulating in activated platelets. Elevated intravascular TF has been reported in a variety of prothrombotic diseases, but there is debate as to whether anucleate platelets-the key cellular effector of thrombosis-express TF. Our studies demonstrate that human platelets use Clk1-dependent splicing pathways to generate TF protein in response to cellular activation. We propose that platelet-derived TF contributes to the propagation and stabilization of a thrombus.

Simvastatin inhibits tissue factor and plasminogen activator inhibitor-1 expression of glomerular mesangial cells in hypercholesterolemic rabbits

Tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) activity and/or expression are upregulated in hypercholesterolemia. Despite extensive research on anti-thrombotic effect of statins, little is known about their effects on TF and PAI-1 expression in glomerular mesangial cells under hypercholesterolemic condition. Male rabbits were fed on either normal or high-cholesterol diet for 8 weeks. Then cholesterol-fed rabbits were randomly assigned to simvastatin or starch. At the end of 12 weeks, glomerular mesangial cells were collected. The concentrations of TF and PAI-1 mRNA were detected by RT-PCR. The plasma activities of TF and PAI-1 were determined with enzyme linked immunosorbent assay (ELISA) and chromogenic substrate method, respectively. The atherogenic diet caused a consistent increase in serum concentrations of total cholesterol (TC) and serum triglyceride (TG) (p < 0.05), increased TF and PAI-1 mRNA expression in glomerular mesangial cells and plasma activities as compared to the normal diet (p < 0.01). Four-week simvastatin treatment resulted in significant decrease of mesangial TF and PAI-1 mRNA (p < 0.01), and also of the plasma activities of TF (p < 0.05) and PAI-1 (p < 0.01). These results suggest that simvastatin might protect kidney from the formation of microthrombus under hypercholesterolemic condition and might be a possible pathogenesis of obesity-related glomerulopathy.

Differential effect of celecoxib on tissue factor expression in human endothelial and vascular smooth muscle cells

In endothelial cells (EC), celecoxib inhibits expression of tissue factor (TF), a key protein for initiation and propagation of thrombus formation. The current study was designed to examine the effect of celecoxib on TF expression and activity in VSMC. In contrast to EC, celecoxib increased TNF-alpha-induced TF expression and surface activity in VSMC by 33% and 20%, respectively, as compared to TNF-alpha alone, while rofecoxib or NS-398 had no effect. Celecoxib increased p38 MAP kinase (p38), p44/42 MAP kinase (ERK), and p70S6 kinase (p70S6K) phosphorylation while leaving JNK activation unaffected. Simultaneous inhibition of p38 and ERK reduced TNF-alpha-induced TF expression by 59%, while inhibition of JNK with SP600125 did not affect TF expression. Thus, in contrast to endothelial cells, celecoxib does not inhibit TF expression in VSMC, but instead enhances it. As neither rofecoxib nor NS-398 affected TF expression, this effect does not seem to be related to COX-2 inhibition but rather appears to be mediated by an increase in p38, ERK, and p70S6K activation. The observation that the inhibiting effect of celecoxib on endothelial TF expression does not extend to VSMC may have important implications for patients with cardiovascular disease.

[Effects of valsartan and captopril on expressions and activities of tissue factor and tissue factor pathway inhibitor]

OBJECTIVE

To investigate the effects of ox-LDL, ACEI and ARB on expressions and activities of TF and TFPI in VSMC.

METHODS

(1) Rabbit VSMC was cultured by explant-attached method in vitro. (2) The effects of ox-LDL and valsartan on TF and TFPI expressions were analyzed by immunohistochemistry and immunofluorescence. Laser scanning confocal microscopy were applied to analyze the effects of ox-LDL and valsartan on TF expression. The effects of ox-LDL, valsartan and captopril on TF and TFPI antigen expressions were analyzed by ELISA. Chromogenic substrate method was used to determine the effects of ox-LDL, valsartan and captopril on TF activity. The effects of ox-LDL and valsartan on TF mRNA expression were analyzed by RT-PCR.

RESULTS

(1) ox-LDL could upregulate TF antigen, activity and TF expression at mRNA level and downregulate TFPI antigen. (2) Valsartan and captopril could reduce TF antigen and activity in VSMC treated by ox-LDL, and valsartan reduce it in a dose-dependent manner. Valsartan could also attenuate TF expression at mRNA level in VSMC treated by ox-LDL. (3) Using ELISA, valsartan and captopril could also enhance TFPI antigen in VSMC treated by ox-LDL.

CONCLUSION

Our study showed upregulated TF and downregulated TFPI expression and activity by ox-LDL and these effects could be reversed by ACEI and ARB indicating a new insight on the antiatherosclerotic effects of ACEI and ARB.

A human monoclonal antiprothrombin antibody is thrombogenic in vivo and upregulates expression of tissue factor and E-selectin on endothelial cells

Prothrombin is now accepted as one of the target antigens recognised by antiphospholipid (aPL) antibodies. However, it is not clear whether anti-prothrombin antibodies are pathogenic in vivo and if so, the possible mechanism(s) involved. Here, we examined the pathogenic effects of the IS6 monoclonal anti-prothrombin antibody isolated from a patient with Antiphospholipid Syndrome (APS). IS6 antibody was purified from hybridoma supernatant. Its pathogenic potentials were studied in an in vivo model of induced thrombosis. The expression of tissue factor (TF) and E-selectin on human umbilical vein endothelial cells (HUVEC) was determined by cyto-enzyme-linked immunosorbent assay. Transcription of TF mRNA was determined by quantitative real time-polymerase chain reaction (RT-PCR). In vivo, the thrombus size increased significantly when treated with IS6 compared with control-treated mice (5388 +/- 1035 microm2 vs. 2845 +/- 1711 microm2). In vitro, IS6 induced significant expression of TF and E-selectin on HUVEC, when compared with control preparation (3.1- and 5.1-fold increase compared with the control-treated cells). RT-PCR analysis of TF mRNA transcription showed a 2.5-fold increase of IS6-treated cells over the value obtained with control-treated cells. Taken together, these data show that IS6 monoclonal anti-prothrombin antibody promotes thrombosis and this is associated with TF and E-selectin expression.

[Platelet and tissue factor: review]

It is generally accepted that tissue factor plays an important role in coagulation and intravascular thrombus formation. Tissue factor is not only found primarily on the surface of certain cells that are located outside the vasculature, but also found in circulating cells. Monocyte express tissue factor induced by endotoxin. Recently, many researches indicate that P-selectin, CD40 ligand and GPIIb/IIIa receptor of platelet can also affect expression of tissue factor by monocyters. In addition, a lot of studies showed that tissue factor exist in the circulation including contained platelet. Tissue factor in the platelet releases under certain condition, and initiates coagulation. In this review the relation between platelet and tissue factor was elaborated.

Early growth response gene-1 regulates hypoxia-induced expression of tissue factor in glioblastoma multiforme through hypoxia-inducible factor-1-independent mechanisms

Hypoxia strongly up-regulates tissue factor and promotes plasma clotting by glioblastoma multiforme, but transcriptional mechanisms remain undefined. Here, we investigated the potential roles of early growth response gene-1 (Egr-1), Sp1, nuclear factor-kappaB (NF-kappaB), activator protein-1 (AP-1), and hypoxia-inducible factor-1 (HIF-1) in the hypoxic regulation of tissue factor by glioblastoma multiforme cells in vitro. Hypoxia (1% O2) strongly induced Egr-1 mRNA within 1 hour and led to nuclear localization of Egr-1 protein. Using luciferase reporter plasmids in glioma cells, we found that hypoxia dramatically increased luciferase activity in cells with constructs containing Egr-1-binding sites but not in cells with constructs containing AP-1- or NF-kappaB-binding sites. Electrophoretic mobility shift assays revealed hypoxia-induced Egr-1, but not Sp1, binding to oligonucleotides containing the Egr-1/Sp1 motif of tissue factor gene promoter. Using an expression vector containing the minimal tissue factor promoter (-111 to +14 bp) and small interfering RNA (siRNA) directed at Egr-1 and Sp1 mRNAs, we found that Egr-1 was required for maximal hypoxic induction of promoter activity. Forced overexpression of Egr-1 but not Sp1 by cDNA transfection caused up-regulation of tissue factor in glioma cells under normoxia (21% O2), whereas siRNA directed at Egr-1 strongly attenuated hypoxia-induced tissue factor expression. To examine the effects of HIF-1alpha on tissue factor expression, we used glioma cells stably transfected with a HIF-1alpha siRNA expression vector and found that HIF-1alpha mRNA silencing did not affect tissue factor expression under hypoxia. We conclude that hypoxic up-regulation of tissue factor in glioblastoma multiforme cells depends largely on Egr-1 and is independent of HIF-1.

Induction of monocytic tissue factor expression after rewarming from hypothermia in vivo is counteracted by heat shock in c-Jun-dependent manner

OBJECTIVE

Triggering of tissue factor (TF)-mediated blood coagulation leads to the development of disseminated intravascular coagulation during rewarming from hypothermia. We studied post-rewarming TF levels, activity, and surface redistribution, along with the regulation of TF gene transcription in mononuclear cells (MNCs) obtained from an in vivo rat model.

METHODS AND RESULTS

Rewarming after a 5-hour episode of 15 degrees C hypothermia caused an increase in TF activity, protein levels, and externalization of TF antigen in rat MNCs. This was accompanied by a dramatic elevation of c-Jun and JNK phosphorylation, and the absence of EGR-1 and NF-kappaB activation. To search for a stimulus to counteract c-Jun-mediated induction of TF activity in MNCs from rewarmed rats, we applied heat shock pretreatment one day before the hypothermia/rewarming experiment. This restored post-rewarming TF activity, protein levels, and surface-to-total TF ratio in rat MNCs to normothermic levels. Furthermore, in heat shock-pretreated animals, rewarming failed to increase phosphorylated c-Jun and JNK levels. We attribute this to the profound overexpression of heat shock protein 70 and inhibition of JNK.

CONCLUSIONS

MNCs respond to rewarming from hypothermia by an induction of active TF antigen. This effect is dependent on c-Jun activation and is abolished by heat shock pretreatment.

Immunologic quantitation of tissue factors

The large number of conflicting reports on the presence and concentration of circulating tissue factor (TF) in blood generates uncertainties regarding its relevance to hemostasis and association with specific diseases. We believe that the source of these controversies lies in part in the assays used for TF quantitation. We have developed a highly sensitive and specific double monoclonal antibody fluorescence-based immunoassay and integrated it into the Luminex Multi-Analyte Platform. This assay, which uses physiologically relevant standard and appropriate specificity controls, measures TF antigen in recombinant products and natural sources including placenta, plasma, cell lysates and cell membranes. Comparisons of reactivity patterns of various full-length and truncated TFs on an equimolar basis revealed quantitative differences in the immune recognition of TFs by our antibodies in the order of TF 1-263 > 1-242 > 1-218 > placental TF. Despite this differential recognition, all TF species are quantifiable at concentrations < or = 2 pM. Using a calibration curve constructed with recombinant TF 1-263 and plasma from healthy individuals (n = 91), we observed the concentration of TF antigen in plasma to be substantially lower than that generally reported in the literature: TF antigen in plasma of 72 individuals (79%) was below 2 pM (quantitative limit of our assay); TF antigen levels between 2.0 and 5.0 pM could be detected in six individuals (7%); and in 14% (13 plasmas), the non-specific signal was higher than the specific signal, and thus TF levels could not be determined. These differential recognition patterns affect TF quantitation in plasma and should be considered when evaluating plasma TF-like antigen concentrations.

Optimization of conditions for in vitro production of radical oxygen species and expression of tissue factor by canine mononuclear cells and granulocytes for use in high-throughput assays

The purpose of this study was to optimize conditions for high throughput measurement of radical oxygen species (ROS) production and expression of tissue factor, also termed procoagulant activity, by canine leukocytes. Granulocytes and mononuclear cells were separated by density gradient centrifugation from peripheral blood collected on several occasions from three healthy large breed dogs. To determine optimal conditions for ROS production, granulocytes were incubated for 1 or 3h in PBG (PBS containing 0.5% BSA and 5mM glucose) or RPMI containing 10% fetal bovine serum (FBS); lipopolysaccharide (LPS), zymosan, peptidoglycan (PGN) and phorbol myristate acetate (PMA) were used as stimuli. ROS was assessed by conversion of the nonfluorescent dye dihydrorhodamine 123 to fluorescent rhodamine 123 by radical species released into the media. To identify optimal conditions for expression of tissue factor, mononuclear cells were incubated for 5h in RPMI containing different concentrations of heat-inactivated FBS (HI-FBS), and LPS, zymosan, PGN or PMA as stimuli. Expression of tissue factor was determined using a one-stage recalcification assay performed in an automated nephelometric coagulation analyzer. Neither LPS nor zymosan increased ROS production by granulocytes incubated in PBG media. In contrast, granulocytes incubated in RPMI had dose-dependent increases in ROS production in response to zymosan and PGN. ROS production was significantly increased by incubation with concentrations of LPS of 0.01microg/ml or greater, and by zymosan concentrations of 0.1microg/ml or greater. ROS production in response to incubation with PMA was significantly increased starting at 10(-7)M, and was significantly greater for cells incubated in RPMI than cells incubated in PBG. LPS-, zymosan- and PGN-stimulated procoagulant activity increased in a dose-dependent manner, whereas PMA-stimulated procoagulant activity peaked at 10(-7)M. Increasing concentrations of HI-FBS significantly increased LPS-, zymosan- and PGN-induced procoagulant activity of mononuclear cells. Results obtained in this study indicate production of ROS by canine granulocytes is optimal when these cells are incubated for 3h in RPMI with LPS (0.1microg/ml), zymosan (10 microg/ml), PGN (10 microg/ml), and PMA (10(-7)M). Furthermore, canine mononuclear cells express procoagulant activity in response to LPS, zymosan, PGN, and PMA, and responses to LPS, zymosan and PGN are enhanced by the addition of HI-FBS. These findings suggest that HI-FBS retains important serum proteins that facilitate interactions between each of these bacterial or yeast derived products and the mononuclear cells. Consequently, future studies regarding the regulation of procoagulant activity by canine mononuclear cells should be performed in the presence of HI-FBS. Both assays utilized in this study allow high throughput of samples, and therefore are appropriate choices for rapid screening of conditions and/or therapeutic interventions affecting the canine inflammatory system.

Human polymorphonuclear leukocytes produce and express functional tissue factor upon stimulation

BACKGROUND

Blood-borne tissue factor (TF) plays a crucial role in thrombogenesis.

AIM

To study whether polymorphonuclear leukocytes (PMN) are a source of TF.

METHODS AND RESULTS

Human PMN were carefully separated from other blood cells and stimulated for 3 min with purified P-selectin or the chemotactic peptide formyl-MetLeuPhe (fMLP): they expressed both TF procoagulant activity, as identified by specific TF MoAb and inactivated factor VIIa blockade; and TF:Ag (four to six times), as shown by flow-cytometry and immunocytochemistry. About 40% of permeabilized PMN, both resting and stimulated, contained TF:Ag, indicating that stimulation only modifies the location of TF:Ag within PMN. By real time-polymerase chain reaction (RT-PCR), a very low amount of TF mRNA was detectable in resting PMN, but a 3- to 5-fold increase was observed after 1-h stimulation with P-selectin or fMLP, respectively.

CONCLUSIONS

These findings suggest that TF is not constitutively expressed in peripheral PMN, but can be up-regulated and produced upon stimulation and specific gene transcription, as for instance during contact with activated platelets or endothelium. The stored TF is rapidly expressed in vitro as a functional molecule on the surface of activated PMN. The availability of PMN TF supports the relevance of inflammatory cells and their interaction with platelets for fibrin deposition and thrombus formation.

Tissue factor upregulation drives a thrombosis-inflammation circuit in relation to cardiovascular complications

The extrinsic coagulation is recognized as an 'inducible' signalling cascade resulting from tissue factor (TF) upregulation by exposure to clotting zymogen FVII upon inflammation or tissue injury. Following the substantial initiation, an array of proteolytic activation generates mediating signals (active serine proteases: FVIIa, FXa and FIIa) that lead to hypercoagulation with fibrin overproduction manifesting thrombosis. In addition, TF upregulation plays a central role in driving a thrombosis-inflammation circuit. Coagulant mediators (FVIIa, FXa and FIIa) and endproduct (fibrin) are proinflammatory, eliciting tissue necrosis factor, interleukins, adhesion molecules and many other intracellular signals in different cell types. Such resulting inflammation could ensure 'fibrin' thrombosis via feedback upregulation of TF. Alternatively, the resulting inflammation triggers platelet/leukocyte/polymononuclear cell activation thus contributing to 'cellular' thrombosis. TF is very vulnerable to upregulation resulting in hypercoagulability and subsequent thrombosis and inflammation, either of which presents cardiovascular risks. The prevention and intervention of TF hypercoagulability are of importance in cardioprotection. Blockade of inflammation reception and its intracellular signalling prevents TF expression from upregulation. Natural (activated protein C, tissue factor pathway inhibitor, or antithrombin III) or pharmacological anticoagulants readily offset the extrinsic hypercoagulation mainly through FVIIa, FXa or FIIa inhibition. Therefore, anticoagulants turn off the thrombosis-inflammation circuit, offering not only antithrombotic but anti-inflammatory significance in the prevention of cardiovascular complications.

Sources of tissue factor

Tissue factor (TF) exhibits a distinct nonuniform tissue distribution. Thus, high levels are found in highly vascularized organs such as the lung, brain, and placenta; intermediate levels in the heart, kidney, intestine, testes, and uterus; and low levels in the spleen, thymus, and liver. Several cell types are known to express TF constitutively, such as astrocytes in the brain, epithelial cells enveloping organs and body surfaces, adventitial fibroblasts and pericytes, and cardial myocytes in the heart. Smooth muscle cells in the media of the vessel wall and monocytes/macrophages contain small amounts of TF, which is enhanced substantially upon activation of the cells. Endothelial cells probably do not express TF. The popular concept of TF serving predominantly as a hemostatic envelope encapsulating the vascular bed has been challenged recently by the observation that blood of healthy individuals may form TF-induced thrombi under conditions entailing shear stress and activated platelets, corroborating the notion of blood-borne TF. Accordingly, small amounts of decrypted TF activity is detected in calcium ionophore-stimulated monocytes, and microparticles from plasma of healthy subjects possess TF-like activity subject to partial inactivation by anti-TF antibody. In addition to microparticles, plasma TF also comprises the soluble alternatively spliced human TF and truncated TF, both of which probably require factor VIIa to be physiologically active. Although it has been suggested that activated platelets possess active TF, the notion of TF as an integral platelet component is contested by more recent data. Rather, platelets may be very important in decrypting monocyte TF activity in a process entailing transfer of TF to activated platelets.

Tissue factor in cancer and angiogenesis: the molecular link between genetic tumor progression, tumor neovascularization, and cancer coagulopathy

Tissue factor (TF), the primary cellular initiator of blood coagulation, is also involved in cancer-related processes such as hypercoagulability (Trousseau syndrome), tumor growth, angiogenesis, and metastasis. Indeed, elevated TF expression by cancer cells and their associated endothelial cells has been reported frequently. Oncogenic events in cancer cells (e.g., expression of mutant K- ras, EGFR, PTEN or p53) lead to an increase in TF levels and activity, and thereby promote tumor aggressiveness, angiogenesis, and hypercoagulability. Like TF, thrombin receptor (protease-activated receptor-1) is also upregulated in cancer cells expressing oncogenic K -ras. Pharmacological antagonists of some of these transforming genes (e.g., epidermal growth factor receptor inhibitors) could diminish TF expression, both locally and systemically, and hence these targeted agents could be viewed as potential indirect and cancer-specific anticoagulants, in addition to their direct antitumor effects. We postulate that levels of circulating TF may be useful in monitoring the biological activity of these agents. Although TF is essential for vascular development, its expression by tumor-associated endothelium appears to play a subtle and seemingly dispensable role. Thus, TF is a pivotal element of the tumor-vascular interface, is involved in many cancer-related processes, and may well constitute a promising new target for anticancer combination therapies in some disease settings.

The prognostic value of tissue factor levels in acute ischaemic stroke

INTRODUCTION

There is no biological marker that can accurately predict the prognosis after an acute ischaemic stroke. The main objective of this study was to evaluate the prognostic value of tissue factor (thromboplastin) levels in first ischaemic stroke.

METHODS

This was a prospective study of all patients with first ischaemic stroke conducted from October 2003 to February 2004. Plasma for tissue factor levels was kept at -80 degrees Celsius and was analysed at the end of the study period by an independent person. The activities of daily living (ADL) were assessed by using the Barthel index (BI) on admission and at one month after the stroke onset. Any death or recurrent events were recorded.

RESULTS

50 patients were recruited into the study. The median tissue factor level was 184.5 +/- 97.3 pg/ml. Only age (p-value is 0.027) and middle cerebral artery (MCA) infarcts (p-value is 0.038) were found to be significant independent predictors for severe disability at one month with BI equal to or less than 9. There was no correlation of tissue factor level with BI at one month post-stroke (r equals -0.028, p-value is 0.846) and there was also no significant relationship between levels of tissue factor and recurrent events (p-value is 0.41).

CONCLUSION

There is no correlation between tissue factor levels with acute ischaemic stroke outcome.

Biologically active CD40 ligand is elevated in sickle cell anemia: potential role for platelet-mediated inflammation

OBJECTIVE

After activation, platelets expose CD40 ligand (CD40L) on their surface, then subsequently release the inflammatory mediator as a soluble fragment (sCD40L). Because sickle cell anemia (SCA) is noted for both platelet activation and chronic inflammation, we asked whether platelet-released CD40L potentially plays a role in SCA.

METHODS AND RESULTS

ELISAs demonstrate that SCA patient plasma contains 30-fold more sCD40L than control plasma. Correspondingly, platelets from these patients contain less than half the CD40L found in control platelets. Platelets from patients in painful crises are further depleted of CD40L, with even higher plasma levels, suggesting a correlation to the patient's clinical state. In addition, elevated sCD40L correlates with increased tissue factor in SCA plasma. Blockage of the CD40L receptor CD40 reduces SCA plasma-induced production of tissue factor and endothelial intercellular adhesion molecule-1 (ICAM-1). Finally, sCD40L activity in SCA plasma is confirmed by its induction of B-cell proliferation.

CONCLUSIONS

Platelet-derived sCD40L is elevated in SCA, further elevated in crises, and biologically active. The participation of sCD40L in SCA plasma-induced production of B cells, tissue factor, and ICAM-1 suggests that CD40L may contribute to the chronic inflammation and increased thrombotic activity known to occur in SCA.

Identification of a novel human tissue factor splice variant that is upregulated in tumor cells

Tissue factor (TF) is a transmembrane glycoprotein that serves as the prime initiator of blood coagulation and plays a critical role in thrombosis and hemostasis. In addition, a variety of tumor cells overexpress cell-surface TF, which appears to be important for tumor angiogenesis and metastasis. To elucidate the mechanism involved in the upregulation of TF in human tumor cells, a comprehensive analysis of TF mRNA from various normal and tumor cells was performed. The results of these studies indicate that, in addition to possessing a normal full-length TF transcript and minor levels of an alternatively spliced transcript known as alternatively-spliced tissue factor (asTF), human tumor cells express additional full-length TF transcripts that are also generated by alternative splicing. Reverse transcriptase-polymerase chain reaction (RT-PCR) and 5'-rapid amplification of cDNA ends- (5'-RACE) based analyses of cytoplasmic RNA from normal and tumor cells revealed that there is alternative splicing of the first intron between exon I and exon II resulting in 2 additional TF transcripts. One of the transcripts has an extended exon I with inclusion of most of the first TF intron (955 bp), while the second transcript is formed by the insertion of a 495 bp sequence, referred to as exon IA, derived from an internal sequence of the first intron. The full length TF transcript with alternatively spliced novel exon IA, referred to as alternative exon 1A-tissue factor (TF-A), represented approximately 1% of the total TF transcripts in normal cells, but constituted 7-10% of the total TF transcript in tumor cells. Quantitative real-time RT-PCR analysis indicated that cultured human tumor cells contain 10-25-fold more copy numbers of TF-A in comparison to normal, untransformed cells. We propose that high-level expression of the novel TF-A transcript, preferentially in tumor cells, may have utility in the diagnosis and staging of a variety of solid tumors.

Prothrombotic activity is associated with the anatomical as well as the functional severity of peripheral arterial occlusive disease

The importance of prothrombotic activity in cardiovascular disease has been well established. However, limited data exist on the relationship between prothrombotic activity and the severity of peripheral arterial occlusive disease (PAD). The objective of the present study was to investigate the relationship between markers of haemostasis and the diagnostic measures of PAD: ankle-brachial-index (ABI), maximum treadmill walking distance and angiographic score. In a cross-sectional study of 127 patients (mean age 66 years; 64% males) with angiographically verified PAD, fasting blood samples were drawn, and citrated plasma was obtained for determination of selected haemostatic variables: von Willebrand factor (vWF), thrombomodulin (sTM), thrombin-antithrombin complex (TAT), soluble tissue factor (sTF), tPA antigen (tPAag) and D-dimer were all significantly correlated with the angiographic score (p < 0.05 for all). D-dimer, tPAag and fibrinogen were inversely correlated with the maximum treadmill walking distance, (p < 0.0001, p < 0.04 and p < 0.05, respectively), whereas fibrinogen was the only variable correlating to ABI (r = -0.223, p < 0.05). After adjustment for relevant covariates, D-dimer and TAT remained statistically significantly associated with the angiographic score (p < 0.001), and fibrinogen was, independent of other risk factors, inversely related with both the maximum treadmill walking distance and the ABI (p < 0.01 for both). This rather large study in patients with PAD showed that plasma levels of D-dimer, TAT and fibrinogen significantly predicted the extent of atherosclerosis, evaluated by angiographic score, maximum treadmill walking distance and ABI, respectively. These findings demonstrate a prothrombotic state in PAD patients, which might be of importance in future diagnosis and treatment of the disease.

Antiphospholipid antibodies from patients with the antiphospholipid syndrome induce monocyte tissue factor expression through the simultaneous activation of NF-kappaB/Rel proteins via the p38 mitogen-activated protein kinase pathway, and of the MEK-1/ERK pathway

OBJECTIVE

Antiphospholipid syndrome (APS) is characterized by thrombosis and the presence of antiphospholipid antibodies (aPL). In patients with primary APS, expression of tissue factor (TF) on the surface of monocytes is increased, which may contribute to thrombosis in these patients. However, the intracellular mechanisms involved in aPL-mediated up-regulation of TF on monocytic cells are not understood. This study was undertaken to investigate the intracellular signals induced by aPL that mediate TF activation in monocytes from APS patients.

METHODS

We analyzed, both in vivo and in vitro, aPL interactions with proteins that have signaling functions, including mitogen-activated protein kinases (MAP kinases) and NF-kappaB/Rel proteins.

RESULTS

In vivo studies demonstrated significantly higher levels of both TF messenger RNA and TF protein in monocytes from APS patients compared with controls. At the molecular level, increased proteolysis of IkappaBalpha and activation of NF-kappaB were observed. Constitutive activation of both p38 and ERK-1 MAP kinases was also found. Treatment of normal monocytes with aPL activated ERK-1 and p38 MAP kinases, as well as the IkappaB/NF-kappaB pathway, in a dose-dependent manner. NF-kappaB activation and IkappaBalpha degradation induced by aPL were inhibited by the NF-kappaB inhibitor SN50 and the p38 MAP kinase inhibitor SB203580, thus suggesting crosstalk between these pathways. However, the MEK-1/ERK inhibitor PD98059 did not affect aPL-induced NF-kappaB binding activity. TF expression induced by aPL was significantly inhibited by combined treatment with the 3 inhibitors.

CONCLUSION

Our results suggest that aPL induces TF expression in monocytes from APS patients by activating, simultaneously and independently, the phosphorylation of MEK-1/ERK proteins, and the p38 MAP kinase-dependent nuclear translocation and activation of NF-kappaB/Rel proteins.

Cocaine unbalances endothelial tissue factor and tissue factor pathway inhibitor expression

Cocaine consumption can lead to myocardial infarction. Tissue factor (TF) has been implicated in acute coronary syndromes, and the balance of TF and tissue factor pathway inhibitor (TFPI) determines initiation of thrombus formation. This study was designed to investigate the effect of cocaine on endothelial TF and TFPI expression. Cocaine (10(-8)-10(-5) mol/l) increased thrombin-induced TF expression by 24% at 10(-7) mol/l (P < 0.001) without affecting basal TF expression. In contrast, cocaine reduced endothelial TFPI expression by 47% at 10(-7) mol/l (P < 0.01). Moreover, thrombin impaired endothelial TFPI expression, and cocaine (10(-8) mol/l) further reduced TFPI expression by 33% as compared to thrombin (P < 0.02). These effects occur at cocaine concentrations usually present in plasma of consumers. Given the importance of TF in the pathogenesis of acute coronary syndromes, TF induction in conjunction with TFPI suppression may be relevant for the increased frequency of myocardial infarction observed in cocaine consumers.

Enhanced pulmonary inflammation following experimental intracerebral hemorrhage

The association between brain damage and respiratory dysfunction has been recognized although mechanistic link between the two is still poorly defined. Intracerebral hemorrhage is accompanied by brain injury, stroke, and parenchymal hematoma formation with surrounding inflammation. Increase intracranial pressure as a result of intracerebral hemorrhage may promote localized activation of cytokines and coagulation system including tissue factor release. However, whether intracerebral hemorrhage triggers inflammation in noncerebral organs has not been elucidated. The aim of the present study was to examine the impact of intracerebral hemorrhage on lung inflammatory response. Intracerebral hemorrhage was induced by stereotaxic intrastriatal administration of bacterial collagenase. Expression of intracellular adhesion molecule-1 (ICAM-1), IKB-alpha, tissue factor, tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) was evaluated by Western blot analysis. Our results revealed that intracerebral hemorrhage upregulated expression of ICAM-1 and tissue factor in both brain and lung, whereas it enhanced TNF-alpha and IL-1beta mainly in brain within 6 and 24 h of the brain injury. Levels of IKB-alpha remained unchanged in brain and lung tissues. Appearance of inflammatory markers in the lung was accompanied by morphological pulmonary damage. These data suggest that intracerebral hemorrhage may trigger acute inflammatory response in both brain and lung.

[Expression of tissue factor induced by IL-6 in HUVEC]

OBJECTIVE

To investigate the effects of IL-6 at the expression of tissue factor (TF) in human vein endothelial cells(HUVECs).

METHODS

HUVECs were incubated with IL-6 at the concentration of 0.5 ng/mL. Cell viability was measured by CCK-8 assay. The TF mRNA was detected by reverse transcript-polymerase chain reaction(RT-PCR) method.

RESULTS

When HUVECs were exposed to IL-6 (0.5 ng/mL) within a period of 72 h, their viability did not decrease in comparison with the control; there was no statistical difference between the two groups. After the HUVECs were exposed to IL-6 (0.5 ng/mL) for 6 h, the TF mRNA level increased, and it reached the peak at 12 h; then it began to decline. The expression of TF mRNA induced by IL-6 was evidently detected from 6 h to 48 h. After the HUVECs were treated by IL-6 over 72 h, the expression of TF mRNA was no longer detected in HUVECs.

CONCLUSION

IL-6 at the concentration of 0.5 ng/mL did not exert direct effect on cell viability. The increase of TF mRNA expression in HUVECs induced by IL-6 could play an important role in the modulation of blood coagulation disorder and in the mechanism related to coagulation system changes during