Elevated plasma tissue factor antigen level in patients with disseminated intravascular coagulation

Thrombin Generation by Exposure of Blood to Endotoxin: A Simple Model to Study Disseminated Intravascular Coagulation

Pathologic disseminated intravascular coagulation (PDIC) is a serious complication in sepsis. In an in-vitro system consisting of incubation of fresh citrated blood with lipopolysaccharides (LPS) or glucans and subsequent plasma recalcification plasmatic thrombin was quantified. Five hundred microliters of freshly drawn citrated blood of healthy donors were incubated with up to 800 ng/mL LPS ( Escherichia coli) or up to 80 μg/mL Zymosan A (ZyA; Candida albicans) for 30 minutes at room temperature (RT). The samples were centrifuged, and 30 μL plasma were recalcified with 1 volume or less of CaCl2 (25 μmoles Ca2+/mL plasma). After 0 to 12 minutes (37°C), 20 μL 2.5 M arginine, pH 8.6, were added. Thirty microliters 0.9 m M HD-CHG-Ala-Arg-pNA in 2.3 M arginine were added, and the absorbance increase at 405 nm was determined. Fifty microliters plasma were also incubated with 5 μL 250 m M CaCl2 for 5, 10, or 15 minutes (37°C). Fifty microliters 2.5 M arginine stops coagulation, and 50 μL 0.77 m M HD-CHG-Ala-Arg-pNA in 2.3 M arginine starts the thrombin detection. The standard was 1 IU/mL thrombin in 7% human albumin instead of plasma. Arginine was also added in the endotoxin exposure time (EET) or in the plasma coagulation reaction time (CRT). Tissue factor (TF)-antigen and soluble CD14 were determined. LPS at blood concentrations greater than 10 ng/mL or ZyA at greater than 1 μg/mL severalfold enhance thrombin generation, when the respective plasmas are recalcified. After 30 minutes EET at RT, the thrombin activity at 12 minutes CRT generated by the addition of 200 ng/mL LPS or 20 μg/mL ZyA is approximately 200 mIU/mL compared to approximately 20 mIU/mL without addition of endotoxin, or compared to about 7 mIU/mL thrombin at 0 minutes CRT. Arginine added to blood or to plasma inhibits thrombin generation; the inhibitory concentration 50% (IC 50) is approximately 15 m M plasma concentration. Endotoxin incubation of blood increases neither TF nor sCD14. This assay allows the study of the hemostasis alteration in PDIC, particularly in PDIC by sepsis. The thrombin generated by blood plus endotoxin incubation and plasma recalcification suggests that the contact phase of coagulation; e.g., triggered by cell components of (phospholipase-) lysed cells such as monocyte or endothelium DNA or phospholipid-vesicles (microparticles), is of primary pathologic importance in sepsis-PDIC. Arginine at plasma concentrations of 10 to 50 m M might be a new therapeutic for sepsis-PDIC.

Cyclooxygenase-2-derived prostacyclin regulates arterial thrombus formation by suppressing tissue factor in a sirtuin-1-dependent-manner

BACKGROUND

Selective inhibitors of cyclooxygenase (COX)-2 increase the risk of myocardial infarction and thrombotic events, but the responsible mechanisms are not fully understood.

METHODS AND RESULTS

We found that ferric chloride-induced arterial thrombus formation was significantly greater in COX-2 knockout compared with wild-type mice. Cross-transfusion experiments excluded the likelihood that COX-2 knockout platelets, despite enhanced aggregation responses to collagen and thrombin, are responsible for increased arterial thrombus formation in COX-2 knockout mice. Importantly, we observed that COX-2 deletion decreased prostacyclin synthase and production and peroxisome proliferator-activated receptor- and sirtuin-1 (SIRT1) expression, with consequent increased upregulation of tissue factor (TF), the primary initiator of blood coagulation. Treatment of wild-type mice with a prostacyclin receptor antagonist or a peroxisome proliferator-activated receptor-δ antagonist, which predisposes to arterial thrombosis, decreased SIRT1 expression and increased TF activity. Conversely, exogenous prostacyclin or peroxisome proliferator-activated receptor-δ agonist completely reversed the thrombotic phenotype in COX-2 knockout mice, restoring normal SIRT1 levels and reducing TF activity. Furthermore, inhibition of SIRT1 increased TF expression and activity and promoted generation of occlusive thrombi in wild-type mice, whereas SIRT1 activation was sufficient to decrease abnormal TF activity and prothrombotic status in COX-2 knockout mice.

CONCLUSIONS

Modulation of SIRT1 and hence TF by prostacyclin/peroxisome proliferator-activated receptor-δ pathways not only represents a new mechanism in controlling arterial thrombus formation but also might be a useful target for therapeutic intervention in the atherothrombotic complications associated with COX-2 inhibitors.

Circulating microparticles and endogenous estrogen in newly menopausal women

BACKGROUND

Estrogen modulates antithrombotic characteristics of the vascular endothelium and the interaction of blood elements with the vascular surface. A marker of these modulatory activities is formation of cell-specific microparticles. This study examined the relationship between blood-borne microparticles and endogenous estrogen at menopause.

METHODS

Platelet activation and plasma microparticles were characterized from women being screened (n = 146) for the Kronos Early Estrogen Prevention Study. Women were grouped according to serum estrogen (< 20 pg/ml; low estrogen, n = 21 or > 40 pg/ml; high estrogen, n = 11).

RESULTS

Age, body mass index, blood pressure and blood chemistries were the same in both groups. No woman was hypertensive, diabetic or a current smoker. Platelet counts, basal and activated expression of P-selectin on platelet membranes were the same, but activated expression of glycoprotein IIb/IIIa was greater in the high-estrogen group. Numbers of endothelium-, platelet-, monocyte- and granulocyte-derived microparticles were greater in the low-estrogen group. Of the total numbers of microparticles, those positive for phosphatidylserine and tissue factor were also greater in the low-estrogen group.

CONCLUSION

These results suggest that, with declines in endogenous estrogen at menopause, numbers of procoagulant microparticles increase and thus may provide a means to explore mechanisms for cardiovascular risk development in newly menopausal women.

Vascular smooth muscle-derived tissue factor is critical for arterial thrombosis after ferric chloride-induced injury

Tissue factor (TF) initiates coagulation, regulates hemostasis, and plays a critical role in mediating arterial thrombosis. TF is up-regulated in vascular smooth muscle cells (VSMCs) in atherosclerosis and arterial injury. To examine the biologic role of VSMC-derived TF, we crossed TF(flox/flox) mice with SM22alphaCre(+/-) mice. TF mRNA and activity were decreased in the aortic media of TF-deficient mice by 96% and 94.8%, respectively. There were no differences in TF activity measured in plasma or concentrated microparticles. TF-deficient mice were generated with the expected frequency, showed no evidence of bleeding or increased mortality, and had similar activated partial thromboplastin and tail vein bleeding times. Thrombus-mediated flow reduction in response to ferric chloride injury of the carotid arteries was significantly attenuated in VSMC-specific TF-deficient. Stable occlusion was seen in 11 of 12 wild-type mice, but in only 6 of 16 VSMC-specific TF-deficient mice (P = .001). These data suggest that VSMC-derived TF is critical in a macrovascular model of arterial thrombosis. This mouse model should be valuable in determining the contribution of VSMC-derived TF in other TF-mediated phenomena, such as restenosis.

Impact of neutrophil apoptosis on haemostatic activation in chronic liver disease patients

Recent studies suggest the impact of apoptosis on the mechanisms leading to hypercoagulability. We aimed to clarify the potential role of neutrophil apoptosis in neutropenia and hypercoagulable state encountered in chronic liver disease patients. This study was conducted on 15 normal controls and 45 patients with chronic liver disease classified according to modified Child Pugh classification into, Child A, B and C groups (15 cases each). Haemostatic parameters studied include, prothrombin time, partial thromboplastin time, tissue factor, protein C antigen, protein S antigen, and markers of haemostatic activation [prothrombin fragment 1+2 (F1+2), thrombus precursor protein (TpP) and D-dimer]. Flowcytometric study was done for quantitative assay of neutrophil apoptotic subpopulations to detect the percentage of early and late apoptotic, and necrotic neutrophils using Annexin V-FITC/propidium iodide dye. Semiquantitative assay of apoptotic neutrophils showing DNA fragmentation was performed on neutrophil culture using terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling test. In addition to enzyme-linked immunosorbent assay for soluble Fas (APO-1/CD95) in culture supernatant. The results revealed a rise in the neutrophil apoptotic and necrotic markers with progression of the disease, and they were inversely correlated with the absolute neutrophil count. The apoptotic neutrophil cells showed a significant positive correlation with several haemostatic parameters (tissue factor, prothrombin fragment 1+2, thrombus precursor protein and D-dimer). Regression analysis proved that apoptotic parameters are independent determinants of prothrombotic markers, which further incriminate the apoptotic mechanisms in the hypercoagulable state encountered in this clinical setting.

Coagulation Activation by Lipopolysaccharides

Lipopolysaccharides at approximate plasma reactivities >3 ng/mL or β-glucans at >0.5-1 μg/mL are toxic for human blood; lipopolysaccharide interacts with membrane components of susceptible cells (eg, monocytes) activating phospholipase A2that destroys the cell membrane. Cell fragments (microparticles or DNA) possess polynegative niches that activate intrinsic hemostasis. Pathologic disseminated intravascular coagulation arises. Blood vessels are obstructed by disseminated thrombi, and vital organ areas become ischemic. Multiorgan failure threatens life of the patient. Diagnosis and therapy of pathologic disseminated intravascular coagulation is of extreme clinical importance. For early diagnosis of pathologic disseminated intravascular coagulation, specific activation markers of coagulation (eg, plasmatic amidolytic thrombin activity) or the plasmatic lipopolysaccharide or glucan reactivity can be measured. A new treatment target might be kallikrein or factor XIIa; 10 to 20 mM arginine is the approximate 50% inhibitory concentration against the contact phase of coagulation. The complex interaction between cell fragments and hemostasis causes pathologic disseminated intravascular coagulation in sepsis.

Role of tissue factor in hemostasis and thrombosis

Tissue factor (TF) is a transmembrane glycoprotein that functions as the primary cellular initiator of blood coagulation. Perivascular cells express TF and provide a hemostatic barrier to limit hemorrhage after vessel injury. In addition, TF is expressed in a tissue-specific manner with high levels in vital organs, such as the heart and lung. TF expression in these tissues may provide additional hemostatic protection from mechanical injury to blood vessels. Recent studies have also detected TF in the blood. This circulating TF is present in the form of microparticles (MPs), which are membrane vesicles shed from cells, and possibly platelets. At present, the cell types that contribute to this pool of TF-positive MPs have not been fully defined. Monocytes, endothelial cells and platelets are the most likely sources of this circulating TF. However, TF-positive MPs represent only a minor subset of circulating MPs. Importantly, TF-negative MPs also possess procoagulant activity. In various diseases, such as sepsis and cancer, TF is expressed by vascular cells and this leads to thrombosis. Levels of circulating TF are also elevated in these diseases and may contribute to thrombosis. Recent studies have analyzed the role of TF-positive MPs in thrombus propagation using different in vivo models. Circulating TF was found to contribute to thrombosis in some models but not others. Inhibition of TF activity in patients with TF expression in vascular cells and with elevated levels of circulating TF may decrease thrombosis associated with a variety of diseases.

Tissue factor and tumor: clinical and laboratory aspects

This review summarizes data demonstrating the role of TF in tumor development, metastasis and angiogenesis. TF is a transmembrane protein that is expressed constitutively in some kinds of extravascular cells and transiently in intravascular cells after stimulation with cytokines and growth factors. Originally TF was considered to have a function in the initiation of coagulation. In the last years it became evident that TF plays a role in physiological and pathological processes outside the hemostasis. Up-regulation of TF expression appears to be characteristic of tumor tissue. In a variety of human tumors it was shown by immunohistochemistry, that TF can be expressed in malignant cells as well as in tumor-infiltrating macrophages or endothelial cells. Such abnormal TF expression contributes to the angiogenic process by a shift in the balance between endogenous proangiogenic and antiangiogenic factors. Observations of a significant correlation between elevated TF expression with increased microvessel density and VEGF expression underline the TF involvement in tumor angiogenesis. Furthermore, TF expression influences also metastasis. The effect of TF on metastasis may result from its angiogenic effect, but also from the production of growth factors or adhesion proteins.

Hemostatic abnormalities and leukocyte activation caused by infection in patients with malignant lymphoma during chemotherapy

Hemostatic parameters were examined before and during 102 courses of chemotherapy in 42 patients with malignant lymphoma with high risk for infection. The white blood cell count was significantly reduced in all patients at days 1 and 3, but significantly increased at days 7 and 9, compared to before chemotherapy. At day 7 of chemotherapy, tissue factor (TF) mRNA levels in leukocytes were significantly increased in all patients, especially those with infection. Plasma concentrations of granulocyte elastase derived-XDP (GE-XDP) levels correlated with D-dimer levels during chemotherapy in patients with malignant lymphoma, suggesting that the elevated D-dimer is fibrin products degraded by granulocyte elastase. GE-XDP, C-reactive protein (CRP), GE-XDP and D-dimer were significantly higher in patients with infection, disseminated intravascular coagulation (DIC) and acute respiratory distress syndrome (ARDS) than those without. In patients with DIC or ARDS, TF mRNA correlated with D-dimer, and GE-XDP correlated with leukocyte count, CRP and D-dimer, suggesting that inflammatory changes due to thrombosis may cause the activation of leukocytes in patients with malignant lymphoma during chemotherapy. Activated leukocytes and granulocyte elastase may elicit a hypercoagulable state and ARDS in patients with malignant lymphoma during chemotherapy.

Recombinant human factor VIIa-induced alterations in tissue factor and thrombomodulin in patients with advanced liver cirrhosis

BACKGROUND

Recombinant human factor VIIa (rhFVIIa) is used to treat hemophilia and occasionally individuals with liver disease. The aim of the present study was to investigate the consequences of rhFVIIa in individuals with advanced liver disease in an attempt to understand the mechanism of action of rhFVIIa in this unique population.

METHODS

Levels of plasma tissue factor, plasminogen activator inhibitor-1, tissue factor pathway inhibitor, fibrin split products, D-dimers and free thrombomodulin were measured following the administration of rhFVIIa in 17 subjects. The results were compared to normal controls.

RESULTS

The prothrombin time declined from 20.2 +/- 2.8 s to 14.3 +/- 3.9 s (P < 0.01). No change in the activated partial thromboplastin time occurred. A 15.6% reduction in thrombomodulin was observed (P < 0.05). A mean 75.2% reduction in plasma tissue factor occurred (P < 0.01). Tissue factor pathway inhibitor levels declined to less than the control value (P < 0.05). No changes in plasminogen activator inhibitor-1, fibrin split products or D-dimer levels occurred.

CONCLUSIONS

These data demonstrate that rhFVIIa administration to individuals with liver disease results in (i) a transient improvement in the prothrombin time; (ii) no change in the activated partial thromboplastin time; and (iii) a marked reduction in the levels of thrombomodulin and tissue factor. These data suggest that rhFVIIa binds tissue factor and enhances tissue factor and thrombomodulin clearance from the circulation.

Elevated levels of leukocyte tissue factor mRNA in patients with venous thromboembolism

Tissue factor (TF) mRNA levels in leukocyte and TF antigen in plasma were examined in patients with deep vein thrombosis (DVT). Although TF mRNA levels in leukocytes were higher in patients with DVT than in healthy volunteers, they were lower in patients with DVT than in those with solid cancer and those with disseminated intravascular coagulation (DIC). On the other hand, the plasma levels of TF antigens were markedly high in patients with DVT/pulmonary embolism (PE). Analysis of the role of underlying disease of DVT showed no significant difference in TF mRNA levels and TF antigens among patients with solid cancer, post-surgical, other diseases and those free of underlying diseases. In patients with VTE, plasma levels of D-dimer, soluble fibrin, GE-XDP and plasminogen activator inhibitor-1 did not correlate with TF mRNA or TF antigen. In analysis of 18 patients with PE with and without DVT, TF mRNA levels in leukocytes correlated with the plasma levels of D-dimer. These findings suggest that TF in leukocytes is more likely to be involved in the development of thrombosis in PE than DVT.

The cytoplasmic domain of tissue factor contributes to leukocyte recruitment and death in endotoxemia

Tissue factor (TF) is an integral membrane protein that binds factor VIIa and initiates coagulation. The extracellular domain of TF is responsible for its hemostatic function and by implication in the dysregulation of coagulation, which contributes to death in endotoxemia. The role of the cytoplasmic domain of tissue factor in endotoxemia was studied in mice, which lack the cytoplasmic domain of TF (TF(deltaCT/deltaCT)). These mice develop normally and have normal coagulant function. Following i.p injection with 0.5 mg of lipopolysaccharide (LPS), TF(deltaCT/deltaCT) mice showed significantly greater survival at 24 hours compared to the wt mice (TF(+/+)). The serum levels of TNF-alpha and IL-1beta were significantly lower at 1 hour after LPS injection and IL-6 levels were significantly lower at 24 hours in TF(deltaCT/deltaCT) mice compared to TF(+/+)mice. Neutrophil recruitment into the lung was also significantly reduced in TF(deltaCT/deltaCT) mice. Nuclear extracts from tissues of endotoxemic TF(deltaCT/deltaCT) mice also showed reduced NFkappaB activation. LPS induced leukocyte rolling, adhesion, and transmigration in post-capillary venules assessed by intravital microscopy was also significantly reduced in TF(deltaCT/deltaCT) mice. These results indicate that deletion of the cytoplasmic domain of TF impairs the recruitment and activation of leukocytes and increases survival following endotoxin challenge.

Tissue Factor: A Key Molecule in Hemostatic and Nonhemostatic Systems

Tissue factor (also known as tissue thromboplastin or CD142) is the protein that activates the blood clotting system by binding to, and activating, the plasma serine protease, factor VIIa, following vascular injury. Because of its essential role in hemostasis, tissue factor plays a role in pathology associated with hemostasis, triggering the coagulation system in many thrombotic diseases and the coagulopathies associated with sepsis and other forms of disseminated intravascular coagulation. Recent research has also implicated tissue factor in a variety of nonhemostatic roles, including cell signaling, inflammation, vasculogenesis, and tumor growth and metastasis. This review focuses on both the well-known roles of tissue factor in hemostasis and thrombosis and the newer concepts of tissue-factor biology including how it functions as a signaling receptor and the possible role of blood-borne tissue factor in thrombosis.

Plasma and hepatic tissue levels of thrombomodulin, tissue factor, NFkappaB and nitric oxide in responders and nonresponders to IFNalpha therapy

Hepatitis C virus (HCV) infects hepatocytes and utilizes the hepatocyte to replicate. In so doing, many hepatocyte activities are shifted from their native state to one reflecting liver cell stress. Thrombomodulin and tissue factor are endothelial cell proteins that are expressed as a result of tissue injury or stress. Urokinase is a serine protease, which has been implicated in a number of physiologic and pathologic processes related to cellular stress and or injury. Nitric oxide is produced by cells in response to injury and functions both as a vasodilator and as an activator of a large number of cytokine cascades. NFkappaB is a transcription factor that forms one of the first lines of cellular defense against infection and hepatocellular stress. The levels of these four factors in plasma, hepatocyte cytosol and hepatocyte nuclear extracts provide a precise panoramic measure of cellular stress. Plasma, hepatocyte cytosol and nuclear extracts of hepatocytes were assayed for these four factors in 17 patients treated with alphaIFN for chronic hepatitis C. Five of the 17 were responders while 12 were nonresponders. Ten normal controls and 1 normal control liver were assayed also for each parameter. Nonresponders had 2x the plasma urokinase levels of responders and normals. The cytosol prepared from hepatocytes of nonresponders had a urokinase level 15-fold that of the controls and responders to IFN therapy. Plasma thrombomodulin levels in nonresponders were sixfold greater than those of responders and controls. The levels of all of the other measures in plasma, cytosol and nuclear extracts of liver tissue varied minimally between responders and nonresponders and the normal controls. These data demonstrate that: (i) urokinase levels in plasma and more clearly in cytosol are greater in nonresponders than responders, and (ii) plasma thrombomodulin levels in nonresponders are sixfold greater than those of responders and controls. These data suggest that urokinase and thrombomodulin may be unique markers of cellular and endothelial stress present in individuals with chronic hepatitis C. These markers might be useful during the clinical course of chronic hepatitis C, as a means of gauging the tissue response to therapy.

Pro- and non-coagulant forms of non-cell-bound tissue factor in vivo

BACKGROUND

Concentrations of non-cell-bound (NCB; soluble) tissue factor (TF) are elevated in blood collecting in the pericardial cavity of patients during cardiopulmonary bypass (CPB). Previously, we reported microparticles supporting thrombin generation in such blood samples. In this study we investigated the extent of microparticle association of the NCB form of TF in pericardial and systemic blood, and whether this microparticle-associated form is active in thrombin generation compared with non-microparticle-bound, (fluid-phase) TF.

METHODS

Systemic and pericardial blood samples were collected before and during CPB from six patients undergoing cardiac surgery. Microparticles were isolated by differential centrifugation and their thrombin-generating capacity measured in a chromogenic assay. Microparticle-associated and fluid-phase forms of NCB TF were measured by ELISA. Microparticle-associated TF was visualized by flow cytometry.

RESULTS

In pericardial samples, 45-77% of NCB TF was microparticle-associated, and triggered factor VII (FVII)-mediated thrombin generation in vitro. Microparticles from systemic samples triggered thrombin generation independently of FVII, except at the end of bypass (P = 0.003). The fluid-phase form of TF did not initiate thrombin generation. Both forms of NCB TF were, at least in part, antigenically cryptic.

CONCLUSIONS

We demonstrate the occurrence of two forms of NCB TF. One form, which is microparticle-associated, supports thrombin generation via FVII. The other form, which is fluid-phase, does not stimulate thrombin formation. We hypothesize that the microparticle-associated form of NCB TF may be actively involved in postoperative thromboembolic processes when pericardial blood is returned into the patients.

Tissue specific expression and serum levels of human tissue factor in patients with urological cancer

Human tissue factor (TF) is involved in tumor angiogenesis and metastasis. However, little is known about the distribution of TF in urological cancer. In this study we investigated the TF expression in tumor tissue and autologous non-malignant tissue as well as in serum of patients with renal cell carcinoma (RCC), bladder cancer, and prostate cancer (PCa). To study the distribution of TF in tumor tissue and in the surrounding non-malignant tissue, we measured TF protein by ELISA in tissue specimens obtained intraoperatively from 18 RCC, seven bladder cancer and six PCa patients. Differences in TF expression were found between tumor tissue and nonmalignant tissue for the three tumor types at the protein level (in the order RCC < bladder cancer < PCa). In all but one of the 18 RCC patients (94 %) higher TF protein level was observed in non-malignant tissue as compared to the tumor tissue. In addition, the relative TF mRNA expression analyzed by a quantitative RT-PCR assay in the same RCC tissue sample pairs was higher in 78% of non-malignant tissues in comparison to the tumor tissue specimens. Moreover, using enzyme linked immunosorbent assay the TF protein content was measured in serum samples of 66 patients with bladder cancer, 75 RCC patients and 157 PCa patients, and was compared with the TF serum level of 92 healthy volunteers. Whereas no differences were detected between normal volunteers and patients with PCa or RCC, patients with bladder cancer showed a significantly increased level of serum TF (P=0.0076). However, no causal association between TF levels in serum and TF content in tissue extracts for all three tumor types of urological tumors was found. Our results suggest that TF in non-malignant renal tissues was expressed at a higher level compared to the supposed de novo TF expression in RCC tissue specimens. This indicates a tumor-associated induction of TF expression in the TF-negative RCC progenitor cells. The increased serum TF levels are alike the reported higher urinary TF levels found in bladder cancer patients. The potential clinical relevance of this finding should be further elucidated.

Circulating tissue factor, tissue factor pathway inhibitor and D-dimer in umbilical cord blood of normal term neonates and adult plasma

The investigation of many hemostatic defects in newborns is restricted by the lack of normal reference values. The coagulation system of the neonate differs in many ways from that of the adult. The present study was designed to compare the concentrations of tissue factor (TF), tissue factor pathway inhibitor (TFPI) and D-dimer (DD) in the umbilical cord blood of healthy newborns and in adult plasma. TF antigen was quantified using an in-house enzyme-linked immunosorbent assay, whereas TFPI and DD levels were measured with commercial kits. The mean TF level in cord blood (mean standard deviation, 183.94 103.63 pg/ml) was significantly higher ( = 0.008) than that in adults (136.64 65.09 pg/ml). Cord blood exhibited enhanced fibrinolysis, as was reflected by a significantly higher level of DD (924.57 733.87 ng/ml, 0.001) than that in adults (45.57 17.21 ng/ml). Conversely, cord blood (30.88 10.16 ng/ml) demonstrated significantly lower ( 0.001) TFPI levels than that in adults (55.77 21.16 ng/ml). However, no significant differences of these three hemostatic markers were noted between both gender groups in newborns and adults. Our findings indicate that an active and dynamic state of hemostasis exists in cord blood, as the fluidity of cord blood remains preserved in the presence of birth injury.

The effects of chemotherapeutic agents on the regulation of thrombin on cell surfaces

Thromboembolic disorders are common in cancer patients. Two major contributing factors are central venous catheters for drug delivery and the use of l-aparaginase, which decreases the plasma antithrombin level, but the causes of the hypercoagulable state in these patients are not fully understood. In this study, the T24/83 cell line was used as a model to investigate the effects of chemotherapeutic agents on cell surface thrombin regulation. Plasma thrombin generation and prothrombin consumption was increased in most of the treated cells, particularly vincristine- and adriamycin-treated cells (P < 0.05), compared with controls. However, no free thrombin generation or prothrombin consumption was observed in factor VII (FVII)-depleted plasma. No significant differences in the levels of thrombin-alpha2-macroglobulin (IIa-alpha2M) and thrombin-anti-thrombin (TAT) were observed between controls and any of the treatments, except for vincristine- and adriamycin-treated cells, which showed a significant difference in TAT production (P < 0.05). Also, there was an upregulation in tissue factor (TF) mRNA expression in etoposide-, methotrexate- and vincristine-treated monolayers compared with controls, as well as an upregulation in TF protein production in vincristine-treated cells. The data suggests that thrombin generation occurs via the extrinsic (TF-dependent) coagulation pathway on cell surfaces and that some chemotherapeutic agents are able to upregulate TF mRNA and protein expression in T24/83 cells.

Active tissue factor shed from human arterial smooth muscle cells adheres to artificial surfaces

Through a series of in vitro assays, this study outlines a flow-mediated process by which active tissue factor (TF), the prime initiator of coagulation, may be transferred from the plasma membrane of vascular smooth muscle cells (VSMCs) to that of artificial surfaces such as those typically associated with intravascular implants. Studies with quiescent and activated rat VSMCs demonstrated that pathologically high shear stresses (tau(w) = 250 dyn cm(-2)) resulted in the loss of TF activity from the cell surface. Subsequent experiments with human VSMCs showed that VSMCs continuously release active TF into their extracellular medium, presumably in the form of lipid vesicles or microparticles, and that fluid shear stress (tauw = 50 dyncm(-2)) or chemical agonists (A23187) can significantly accelerate this release. Experiments with a wide array of polymeric and metallic materials showed that the TF shed from VSMCs was able to adhere to these surfaces and promote the activation of coagulation factor X (FX) at the material surface. Extracellular TF bound strongly to both uncoated and human plasma coated surfaces under a wide range of hemodynamic shear stresses (0-20 dyncm(-2)). When an extracellular, VSMC-derived TF mixture was perfused over Ti 6-4 surfaces, the adhesion of TF was found to be time-dependent, gradually accumulating on the material surface over time. Thus an important criterion in the design or success of intravascular devices may be related to their ability to interact with TF, shed from cell surfaces. This is especially important as TF may lead to thrombotic complications, the products of which may also increase cellular proliferation.

Decreased tissue factor and tissue-plasminogen activator antigen in relapsed acute promyelocytic leukemia

This study evaluated hemostatic data in 28 patients with newly diagnosed acute promyelocytic leukemia (APL) and 15 patients with relapsed APL. Activated partial thromboplastin time and prothrombin time were prolonged at initial onset of APL. Plasma level of fibrinogen was significantly decreased in patients with initial disease of APL, but it was not decreased significantly during the relapse of APL. Plasma fibrin and fibrinogen degradation products levels were significantly increased and platelet counts significantly decreased in both groups. Plasma levels of antiplasmin significantly decreased at initial onset but not during relapse. Plasma levels of antithrombin were within normal range in patients with initial disease but significantly decreased in those with relapse. Plasma levels of D-dimer, soluble fibrin monomer (sFM), plasmin-plasmin inhibitor complex (PPIC), and thrombin antithrombin complex (TAT) levels were significantly high in both groups. Plasma levels of PPIC, sFM, and D-dimer were significantly higher at initial onset of APL than during relapse. However, there was no significant difference in DIC score between patients with initial onset and those with relapse; plasma levels of tissue factor (TF) significantly increased in both groups, but they were significantly higher at initial onset of APL than during relapse. TF and tissue type plasminogen activator (t-PA) antigen levels in leukemic cell lysate were significantly increased in both groups, and they were significantly lower during relapse than at initial onset. Hemostatic abnormalities occurring in patients with relapsed APL might be the result of the decrease of TF and t-PA in leukemic cells. These findings suggest that DIC in APL patients with relapse might not be caused only by TF and t-PA and thus should be treated with different therapy from patients with initial onset of APL.

Tissue factor expression in breast cancer tissues: its correlation with prognosis and plasma concentration

Tissue factor (TF), an initiator of the extrinsic coagulation cascade, is expressed in a wide range of cancer cells and plays important roles in cancer progression and metastasis. Recently, the intracellular function of TF has been revealed to be involved in cancer invasion, independent of the blood coagulation pathway. To evaluate the clinical significance of TF expression, we performed an enzyme-linked immunosorbent assay (ELISA) in the plasma of 67 breast cancer patients and immunohistochemistry in 213 breast cancer tissues. In the ELISA study, we showed an up-regulation of plasma TF concentration in breast cancer patients compared with normal controls. Immunohistochemistry demonstrated that TF was expressed in tumour cells and stromal cells and tumour TF expression closely correlated with stromal TF expression (P = 0.0005). The concentration of plasma TF was associated with tissue TF expression in both tumour and stroma. The multivariate analysis demonstrated that tumour TF expression was an independent prognostic indicator for overall survival (P = 0.0452). Our data show that plasma TF concentration reflects tissue TF expression and tumour TF expression can provide some predictive value for prognosis and distant metastasis, which indicates the importance of TF function in tumour progression.

Elevated tissue factor levels in leukemic cell homogenate

Tissue factor (TF) antigen and activity were measured in leukemic cell homogenates. In leukemic cell homogenate, especially that of acute promyelocytic leukemia (APL), both TF antigen and activity were significantly higher than these levels in the mononuclear cells obtained from healthy volunteers. Both TF antigen and activity were significantly higher in myelocytic leukemia than in lymphocytic leukemia cells. In leukemic cell homogenates, there was a close correlation between TF antigen and TF activity. The TF activity/TF antigen ratio was significantly higher in myelocytic leukemia than in lymphocytic leukemia cells. As the TF activity was not increased in lymphocytic leukemia cell homogenates to which were added phospholipids, the decrease in TF activity in lymphocytic leukemia might not be due to phospholipid in the leukemic cell membrane. Values for TF activity, TF antigen, and the TF activity/TF antigen ratio in leukemic cell homogenate from patients with disseminated intravascular coagulation (DIC) were significantly higher than those in patients without DIC. Therefore, the measurement of TF antigen and activity in leukemic cells could be useful for the prediction of DIC.

Hemostatic molecular markers before the onset of disseminated intravascular coagulation

We retrospectively measured various hemostatic markers in 240 patients with disseminated intravascular coagulation (DIC) before the onset of DIC and in 110 non-DIC patients, and examined their usefulness for the diagnosis of pre-DIC. Changes in prothrombin time ratio and fibrinogen levels were not significant before the onset of DIC. The plasma levels of fibrinogen and fibrin degradation products before the onset of DIC were increased and the platelet count was gradually reduced in nonleukemic patients; these changes were already significant in the non-DIC state. The plasma levels of thrombin-antithrombin complex (TAT), plasmin-plasmin inhibitor complex (PPIC), D-dimer, and soluble fibrin monomer (sFM) were increased before the onset of DIC. In leukemic patients, the plasma levels of sFM on day 5, those of TAT on day 3, and D-dimer on day 1, were significantly increased before the onset of DIC. The levels of most hemostatic markers 7 days before the onset of DIC were not different from those observed in the non-DIC state. In nonleukemic patients, only D-dimer, sFM, and TAT levels were significantly increased 7 days before the onset of DIC compared with values in the non-DIC state. The positive rate of hemostatic markers for the diagnosis of DIC, TAT, and PPIC were high during the pre-DIC and non-DIC groups. The plasma levels of sFM and D-dimer were low in non-DIC and increased gradually during the pre-DIC state. These findings suggest that hemostatic molecular markers such as sFM, D-dimer, and TAT are useful for the diagnosis of pre-DIC, although their cutoff values were different among various diseases.

Increased truncated form of plasma tissue factor pathway inhibitor levels in patients with disseminated intravascular coagulation

To evaluate that the relationship between the truncated form of tissue factor pathway inhibitor (TFPI) and the stage of disseminated intravascular coagulation (DIC), we measured the plasma levels of tissue factor (TF) antigen and the intact and truncated forms of TFPI antigens in 41 patients with DIC, 12 with pre-DIC, and 20 with non-DIC. The plasma TF and total TFPI antigen levels were significantly higher in patients with DIC than in non-DIC patients. Plasma levels of intact TFPI antigen in the pre-DIC groups were significantly lower than in the non-DIC and DIC groups. The truncated form of TFPI antigen levels in DIC patients were significantly increased compared with those in non-DIC and pre-DIC patients. The fact that the intact form of TFPI was decreased in pre-DIC patients compared with that in non-DIC patients, suggests that it is consumed in the pre-DIC state and that hypercoagulability occurs in pre-DIC patients. The increased level of the truncated form of TFPI in DIC patients may be attributed to proteolysis of the intact form of TFPI in these patients. The increased level of the truncated form of TFPI may be a useful index for the diagnosis of DIC.

Aberrations of the tissue factor pathway in patients positive for lupus anticoagulant

To evaluate the relationship between the tissue factor (TF) pathway and lupus anticoagulant (LA), in the present study, we measured the plasma levels of TF antigen and TF pathway inhibitor (TFPI) antigen in patients positive for LA. Plasma TF and TFPI levels in LA-positive patients were significantly higher than levels in healthy volunteers (p < 0.01). In LA-positive patients, there were no significant differences in plasma TF and TFPI levels between patients with and without thrombosis. In patients with thrombosis, there was no significant difference in the plasma TF level between LA-positive and LA-negative patients; however, the plasma TFPI level in LA-positive patients was significantly lower than that in LA-negative patients (p < 0.01). We also examined the TF pathway in human umbilical venous endothelial cells (HUVEC) incubated with plasma of LA-positive patients, LA-negative patients, and healthy volunteers. TF activity was significantly higher (p < .05) in HUVECs incubated with the plasma of LA-positive patients than in cells incubated with the plasma of the other two groups (p < .01). However, there was no significant difference in TFPI antigen levels among the media of HUVECs incubated with the plasma of all groups. The viability of HUVEC incubated with the plasma of LA-positive patients with thromboses, LA-positive patients without thromboses, and LA-negative patients with thromboses were significantly lower than that of HUVECs incubated with the plasma of healthy volunteers (p < .01). These findings suggest that abnormalities of the TF pathway plays an important role in the mechanism of hypercoagulability in LA-positive patients. LA may affect vascular endothelial cells causing thrombogenesis.

Pedal manifestations of disseminated intravascular coagulation

Disseminated intravascular coagulation is a complex hemostatic imbalance associated with many disease states. The potentially lethal systemic consequences of this disease mandate that the podiatric physician obtain a complete detailed history in addition to proceeding with appropriate consultations from other specialties. If haste is utilized and surgical intervention is undertaken without careful consideration, a potentially fatal situation may ensue. A comprehensive case report highlighting the pedal presentation and complications, and an overview of this disease process are presented.

Changes of tissue factor activity on inflammatory stimulus and aging in rat

Tissue factor (TF), a principal initiator of the vertebrate coagulation cascade, is expressed in organ tissues, cells and blood. TF is known to be induced in endothelial cells, monocytes and macrophages by inflammatory stimuli and in many pathologic conditions. By using the modified method for in vivo TF activity assay, we found that turpentine oil injection as an inflammatory stimulus also induced the TF activity in lung and brain tissues of rats. And the age-related increase in TF activity was observed in healthy rat brain tissue.

Expression of functional tissue factor on small vesicles of lipopolysaccharide-stimulated human vascular endothelial cells

We examined tissue factor expression on lipopolysaccharide-stimulated endothelial cells and their small vesicles by using specific antibodies and flow cytometry. Tissue factor functional activity was also assessed by activation of factor X. Endothelial cells were stimulated with 10 microg/ml of lipopolysaccharide in M-199/bovine serum albumin. Flow cytometry showed that expression of tissue factor on endothelial cells reached a maximum at 6 hours after stimulation, whereas that on small vesicles reached a maximum after 12 hours. Factor X activation mediated by factor VIIa and tissue factor was observed over a similar time course and was inhibited by the addition of antitissue factor antibody. Immunoelectron microscopy suggested that small vesicles with expression of some tissue factor were produced from the surface of endothelial cells. Our findings thus showed that tissue factor on endothelial cells produced by lipopolysaccharide stimulation was partly released to small vesicles. This may cause disseminated intravascular coagulation and related coagulation disorders.

The sepsis-coagulant axis: a review

Activation of coagulation is a normal component of the acute inflammatory response. Inflammatory cytokines initiate coagulation events locally at sites of inflammation by converting endothelium from an antithrombotic surface to a prothrombotic surface; by stimulating tissue factor production, which activates both the extrinsic and intrinsic coagulation systems; and by stimulating production of platelet-activating factors. The fibrinolytic system is initially activated but is subsequently inhibited. This results in a marked imbalance in coagulation and fibrinolysis resulting in a net procoagulant state. When thrombin generation and platelet activation exceed the body's capacity to inactivate or remove these factors, disseminated intravascular coagulation (DIC) results. DIC directly contributes to multiple organ failure and death associated with sepsis. Presently available treatments (i.e., heparin and aspirin) are relatively ineffective in treating DIC; however, newer, more potent drugs may soon be available for clinical use.

Poor outcome in disseminated intravascular coagulation or thrombotic thrombocytopenic purpura patients with severe vascular endothelial cell injuries

Various hemostatic and vascular endothelial cell markers were measured in patients with disseminated intravascular coagulation (DIC), non-DIC, or thrombotic thrombocytopenic purpura (TTP) and in healthy volunteers to examine the relationships between the hemostatic abnormalities or vascular endothelial cell injuries and the patients' outcomes. Although the plasma levels of soluble fibrin monomer, thrombin-antithrombin complex, plasmin-plasmin inhibitor complex, and D-dimer were significantly increased in the DIC patients, there were no significant differences in these markers between the DIC patients who survived and those who died, suggesting that these markers might not be directly related to the patient outcome. The plasma thrombomodulin (TM) levels in the DIC and TTP patients were significantly higher than those in the healthy volunteers, and the plasma TM levels in the patients who died were significantly higher than those in the patients who survived. These findings showed that the TM level reflected the outcome, and that the outcome of the diseases underlying DIC and TTP might depend on vascular endothelial cell injuries. The plasma protein C and antithrombin activities were markedly reduced in the DIC, non-DIC, and TTP patients who died compared to those who survived. These findings suggest that reduced plasma antithrombin and protein C activities are useful markers of systemic vascular endothelial injuries. Although the plasma tissue factor (TF) levels were significantly increased in the DIC patients, there was no significant difference in the plasma TF levels between the DIC patients who died and those who survived. In conclusion, we found that the outcome of the diseases underlying DIC and TTP is related to vascular endothelial cells, and that plasma TM, antithrombin, and protein C are useful markers for systemic vascular endothelial cell injury.

An activated state of blood coagulation and fibrinolysis in patients with abdominal aortic aneurysm

BACKGROUND

Relationships between blood coagulation and the fibrinolysis system and morphology of aneurysms in patients with abdominal aortic aneurysm (AAA) are unknown.

METHODS

Preoperative and postoperative evaluations of hemostatic factors such as thrombin-antithrombin III complex (TAT), D-dimer, fibrinogen/fibrin degradation products (FDP), and platelet count were performed in 36 patients with atherosclerotic AAA. As control subjects, 25 age- and sex-matched healthy volunteers were analyzed for these hemostatic factors. In all patients, morphological evaluation of AAA included the largest diameter, tortuosity, and the thickness of intraluminal thrombus to be compared with preoperative levels of hemostatic factors such as alpha-2 plasmin inhibitor-plasmin complex (PIC), thrombomodulin (TM), von Willebrand factor (vWF), tissue factor (TF), and free form of tissue factor pathway inhibitor (F-TFPI).

RESULTS

The preoperative values of TAT, D-dimer, and FDP were significantly higher in AAA patients than in controls. Of all patients, 23 (64%) or 22 (58%) had TAT or D-dimer values greater than 8.2 ng/mL or 3.4 microg/mL (mean + 2SD of controls), respectively. The postoperative values of these hemostatic factors significantly improved, but were not normalized. The largest diameter of AAA correlated with the preoperative levels of TAT (r = 0.566, P = 0.001), D-dimer (r = 0.644, P = 0.0001), FDP (r = 0.561, P = 0.0009), PIC (r = 0.413, P = 0.0146), and F-TFPI (r = 0.408, P = 0.0158). We have also found that tortuosity of AAA has relation not only to the preoperative levels of fibrinolytic factors but also to the plasma F-TFPI antigen levels. On the other hand, the preoperative levels of a marker of endothelial damage, such as TM or vWF, and TF did not correlate with those of F-TFPI in all patients. The maximum thickness of thrombus in AAA significantly correlated not only with the preoperative levels of TAT, D-dimer, FDP, and PIC, but also with AAA size.

CONCLUSIONS

We have found evidence that an activated state of both blood coagulation and fibrinolysis in AAA patients is associated with the morphological characteristics of aneurysms.

Plasma tissue factor and tissue factor pathway inhibitor levels in patients with disseminated intravascular coagulation

We measured the plasma levels of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in patients with disseminated intravascular coagulation (DIC) to examine the relationship between TFPI and vascular endothelial cell injury. Plasma TF (273 +/- 90 pg/ml) and TFPI (252 +/- 125 ng/ml) levels were significantly increased in patients with DIC compared with non-DIC patients. Plasma TF antigen level was significantly increased in pre-DIC patients (285 +/- 85 pg/ml), while the plasma TFPI level (152 +/- 54 ng/ml) was not markedly increased in such a state. The plasma TF/TFPI ratio was high in the pre-DIC patients (2.10 +/- 0.90), and low in the DIC patients (1.40 +/- 0.87) and healthy volunteers (0.84 +/- 0.26). There was no significant difference between the DIC patients with a good outcome and those with a poor outcome in terms of plasma TF levels, although the plasma TFPI level in the DIC patients with a good outcome (289 +/- 133 ng/ml) was significantly higher than that in those with a poor outcome (187 +/- 75 ng/ml). During the clinical course of DIC, plasma TF antigen was increased first, and an increase of the plasma TFPI level followed the increase in plasma TF level. These findings suggest that plasma TFPI is released from vascular endothelial cells and it may reflect vascular endothelial cell injury. It is conceivable that TF and TFPI may play an important role in the onset of DIC.

Role of tissue factor in disseminated intravascular coagulation

We examined plasma antigen levels of tissue factor (TF) in 95 cases of disseminated intravascular coagulation (DIC), to investigate the role of TF in DIC. A significant elevation of plasma antigen levels of TF was observed in cases of DIC associated with cancer. However, no such significant elevation was observed in cases of DIC associated with acute promyelocytic leukemia (APL), acute leukemia except APL, blastic crisis of chronic myelogenous leukemia, non-Hodgkin lymphoma (NHL), sepsis or fulminant hepatitis. No significant elevation of TF was observed in patients without DIC, except 4 cases of cancer who developed DIC thereafter. Plasma antigen levels of TF were higher in both cases of DIC with renal failure and chronic renal failure without DIC than its levels in those without renal failure. Therefore, plasma antigen levels of TF in DIC patients with renal failure were considered to be carefully estimated. The levels of TF were decreased with the clinical improvement in some cases of DIC but were further increased or remained at high levels in patients who showed no improvement of DIC. Thus, plasma antigen levels of TF is an important marker to predict the development and/or prognosis of DIC, especially in patients with cancer.

Plasma concentration of tissue factor and factor VII in patients after abdominal surgery

Tissue injury following trauma and surgery may induce alterations in blood coagulation and fibrinolysis. Hypercoagulable state after surgery can be associated with the risk of postoperative thromboembolic complications. The contact of coagulation factors with TF after injury of vessel wall and organ tissues may contribute to the development of thrombosis after surgery (1). TF, the cell surface receptor and cofactor of factor VII/VIIa is normally not expressed by cells within the vasculature. Only monocytes and endothelial cells can be stimulated to express TF transiently by a variety of inflammatory and immunological reactions (for review see 2,3). Also surgical treatment was reported to induce TF synthesis in monocytes (4,5,6). TF is present in many extravascular tissues as vascular adventitia, organ capsules, epidermis, colonic mucosal epithelium, liver stroma, pancreas stroma and also on tumor cells (7-12). In this study, we investigated, whether we can detect the release of TF from the traumatized tissues and from activated monocytes into the circulation following abdominal surgery. To test the dependence of the extension of tissue injury during surgery we segregated the patients into group A with major abdominal operations and group B consisting of patients with appendectomy and cholecystectomy. No relationship could be established between changes of TF and postoperative thromboembolic complications.