Heparanase is highly expressed and regulates proliferation in GH-secreting pituitary tumor cells

Pituitary tumorigenesis involves remodeling of the extracellular matrix (ECM). Heparanase, an endoglycosidase capable of degrading heparan sulfate, a major polysaccharide constituent of the ECM, is implicated in diverse processes associated with ECM remodeling, such as morphogenesis, angiogenesis, and tumor invasion. The aim of this study was to investigate the possible role of heparanase in pituitary tumorigenesis. Human normal pituitaries and pituitary tumors were examined for heparanase mRNA and protein expression using real-time PCR and immunohistochemistry, respectively. Cell proliferation was assessed by colony formation after heparanase overexpression in GH3 and MtT/S cells. Cell viability and cell cycle progression were evaluated after heparanase gene silencing. Higher heparanase mRNA and protein expression was noted in GH tumors as compared with normal pituitaries. Heparanase overexpression in GH3 and MtT/S cells resulted in a 2- to 3-fold increase in colony number, compared with control cells. Cell viability decreased by 50% after heparanase gene silencing due to induced apoptosis reflected by increased fraction of cleaved poly-ADP-ribose polymerase and sub-G1 events. Notably, exogenously added heparanase enhanced epidermal growth factor receptor, Src, Akt, ERK, and p38 phosphorylation in pituitary tumor cells. Our results indicate that heparanase enhances pituitary cell viability and proliferation and may thus contribute to pituitary tumor development and progression.     

Properties and function of heparanase in cancer metastasis and angiogenesis

Cleavage of heparan sulfate proteoglycans affects the integrity and functional state of tissues and thereby fundamental normal and pathological phenomena involving cell migration and response to changes in the extracellular microenvironment. Heparanase, degrading heparan sulfate (HS) at specific intrachain sites, is synthesized as a latent approximately 65 kDa protein that is processed at the N-terminus into a highly active approximately 50 kDa form. The heparanase enzyme is preferentially expressed in human tumors and its overexpression in low-metastatic tumor cells confers a highly invasive phenotype in experimental animals. Heparanase also releases angiogenic factors and accessory fragments of HS from the tumor microenvironment and induces an angiogenic response in vivo. These effects were best demonstrated when the enzyme was secreted and/or expressed on the cell surface. Heparanase may thus facilitate tumor cell invasion, vascularization and survival, all critical events in cancer progression. These observations, the anti-cancerous effect of heparanase-inhibiting molecules, and the unexpected identification of a single predominant functional heparanase suggest that the enzyme is a promising target for drug development.     

Alternatively spliced Spalax heparanase inhibits extracellular matrix degradation, tumor growth, and metastasis

Heparanase is an endoglycosidase that degrades heparan sulfate (HS) at the cell surface and in the extracellular matrix. Heparanase is expressed mainly by cancer cells, and its expression is correlated with increased tumor aggressiveness, metastasis, and angiogenesis. Here, we report the cloning of a unique splice variant (splice 36) of heparanase from the subterranean blind mole rat (Spalax). This splice variant results from skipping part of exon 3, exons 4 and 5, and part of exon 6 and functions as a dominant negative to the wild-type enzyme. It inhibits HS degradation, suppresses glioma tumor growth, and decreases experimental B16–BL6 lung colonization in a mouse model. Intriguingly, Spalax splice variant 7 of heparanase (which results from skipping of exon 7) is devoid of enzymatic activity, but unlike splice 36 it enhances tumor growth. Our results demonstrate that alternative splicing of heparanase regulates its enzymatic activity and might adapt the heparanase function to the fluctuating normoxic–hypoxic subterranean environment that Spalax experiences. Development of anticancer drugs designed to suppress tumor growth, angiogenesis, and metastasis is a major challenge, of which heparanase inhibition is a promising approach. We anticipate that the heparanase splicing model, evolved during 40 million years of Spalacid adaptation to underground life, would pave the way for the development of heparanase-based therapeutic modalities directed against angiogenesis, tumor growth, and metastasis.     

Activated protein C up-regulates procoagulant tissue factor activity on endothelial cells by shedding the TFPI Kunitz 1 domain

Thrombin and activated protein C (APC) signaling can mediate opposite biologic responses in endothelial cells. Given that thrombin induces procoagulant tissue factor (TF), we examined how TF activity is affected by APC. Exogenous or endogenously generated APC led to increased TF-dependent factor Xa activity. Induction required APC's proteolytic activity and binding to endothelial cell protein C receptor but not protease activated receptors. APC did not affect total TF antigen expression or the availability of anionic phospholipids on the apical cell membrane. Western blotting and cell surface immunoassays demonstrated that APC sheds the Kunitz 1 domain from tissue factor pathway inhibitor (TFPI). A TFPI Lys86Ala mutation between the Kunitz 1 and 2 domains eliminated both cleavage and the enhanced TF activity in response to APC in overexpression studies, indicating that APC up-regulates TF activity by endothelial cell protein C receptor-dependent shedding of the Kunitz 1 domain from membrane-associated TFPI. Our results demonstrate an unexpected procoagulant role of the protein C pathway that may have important implications for the regulation of TF- and TFPI-dependent biologic responses and for fine tuning of the hemostatic balance in the vascular system.     

Tissue factor pathway inhibitor expression by human pleural mesothelial and mesothelioma cells.

The mesothelial lining of the pleura and malignant mesothelioma promote fibrin deposition in pleural injury or neoplasia via expression of tissue factor (TF). It was hypothesized that these cells might also regulate intrapleural coagulation by elaborating TF pathway inhibitor (TFPI). TFPI activity and antigen in pleural fluids were assayed from patients with congestive heart failure (CHF), pneumonia, empyema, metastatic pleural cancer and malignant mesothelioma. The authors also assessed expression of TF and TFPI messenger ribonucleic acid (mRNA) as well as TFPI activity and antigen by human pleural mesothelial cells, malignant mesothelioma cells (MS-1 cell line) and human lung fibroblasts. Immunohistochemical analyses of normal, fibrotic, and neoplastic pleura were performed to determine whether TFPI antigen was expressed in vivo. The study revealed that TFPI was present in transudates from patients with CHF and exudative pleural effusions from patients with pneumonia, empyema or pleural carcinoma. TFPI mRNA, activity and antigen were expressed by pleural mesothelial cells, MS-1 cells and lung fibroblasts. Cytokines and serum stimulated a significant early increase in TF mRNA levels with minimal enhancement of TFPI mRNA, activity and antigen levels. TFPI antigen was found in normal, fibrotic and neoplastic pleural tissues. The current observations indicate that tissue factor pathway inhibitor is locally expressed in pleural disease, but that it does not prevent the development of a prothrombotic environment favouring local fibrin deposition in pleural inflammation or cancer.     

乙酰肝素酶与动脉粥样硬化

动脉粥样硬化是致死率较高的常见心血管疾病,乙酰肝素酶是能够裂解细胞外膜中硫酸乙酰蛋白多糖上侧链乙酰肝素的一种内切性β-D-葡萄糖醛酸糖苷酶,且其非酶活性也在许多正常生理活动或病理疾病中发挥作用。研究表明乙酰肝素酶与动脉粥样硬化的形成和进展有着紧密的联系。本文综述了乙酰肝素酶损伤内皮、促凝、诱导炎症因子及脂质聚集等作用,并阐述其在动脉粥样硬化发生发展中的作用及机制。     

Heparanase prevents the development of type 1 diabetes in non-obese diabetic mice by regulating T-cell activation and cytokines production

BACKGROUND: Heparanase is an endo-beta-D-glucuronidase that cleaves heparan sulfate saccharide chains. The enzyme promotes cell adhesion, migration and invasion, and was shown to play a significant role in cancer metastasis and angiogenesis. METHODS: The present study focuses on the involvement of heparanase in autoimmunity, applying the murine non-obese diabetic (NOD) model, a T-cell-dependent disease often used to investigate the pathophysiology of type 1 diabetes. RESULTS: It was found that intra-peritoneal administration of heparanase ameliorated the clinical signs of the disease. In vitro studies revealed that heparanase has an inhibitory effect on the activation of T-cells through modulation of their repertoire of cytokines indicated by a marked increase in the levels of IL-4 and IL-10, and a parallel decrease in IL-12, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). CONCLUSIONS: We suggest that heparanase induces a shift from a Th1- to Th2-phenotype, resulting in inhibition of diabetes in NOD mice and possibly other autoimmune disorders.     

Degranulating mast cells secrete an endoglycosidase that degrades heparan sulfate in subendothelial extracellular matrix.

Mast cells are widely distributed in perivascular connective tissues, especially in areas of active tumor growth and vascular reactivity. Incubation of metabolically [35S]O4 = -labeled subendothelial extracellular matrix (ECM) with lysates of bone marrow-derived mouse mast cells (BMMC) resulted in extensive degradation of heparan sulfate (HS) into fragments 5 to 6 times smaller than intact HS side chains. A much lower activity (seven- to eightfold) was expressed by intact BMMC incubated in contact with the ECM. These fragments were not produced in the presence of heparin, were sensitive to deamination with nitrous acid, and resistant to further degradation with papain or chondroitinase ABC. These results indicate that an endoglycosidase (heparanase) is involved in BMMC-mediated degradation of HS in the subendothelial ECM. Heparanase activity was not detected in medium conditioned by cultured BMMC, or in lysates of Ableson transformed BMMC and rat basophilic leukemic (RBL) cells. Both heparanase and beta-hexosaminidase, a mast cell granule enzyme, were released on degranulation of BMMC induced by the calcium ionophore A23187, or by exposure to IgE-Ag, suggesting that heparanase is localized in the cell granules. Under these conditions, less than 5% of the cellular content of lactate dehydrogenase were released. Degradation of the ECM-HS by the mast cell heparanase and the associated release of HS-bound endothelial cell growth factors that are stored in ECM (Vlodavsky et al, Proc Natl Acad Sci USA 84:2292, 1987; Bashkin et al, Biochemistry 28:1737, 1989) may play a role in the proposed mast cell-mediated stimulation of neovascularization.     

Expression, localization, and activity of tissue factor pathway inhibitor in normal and atherosclerotic human vessels

Tissue factor (TF) pathway inhibitor (TFPI) is the major downregulator of the procoagulant activity of the TF-factor VIIa (FVIIa) complex (TF. FVII). The active TF present in the atherosclerotic vessel wall is proposed to be responsible for the major complication of primary atherosclerosis, namely, acute thrombosis after plaque rupture, but our knowledge of the sites of TFPI expression in relation to TF remains fragmentary. The aim of this study was to investigate the expression, localization, and activity of TFPI and its relation to the activity and distribution of TF in the normal and atherosclerotic vessel wall. We applied a novel approach in which serial cross sections of human vascular segments were used to perform a complete set of assays: immunolabeling for TFPI and/or TF, in situ hybridization for the expression of TFPI mRNA, ELISA for the determination of TFPI antigen, and functional assay for the activity of TFPI and TF. In healthy vessels, TFPI protein and mRNA are present in luminal and microvascular endothelial cells (ECs) and in the medial smooth muscle cells (SMCs). In atherosclerotic vessels, TFPI protein and mRNA frequently colocalized with TF in ECs overlying the plaque and in microvessels, as well as in the medial and neointimal SMCs, and in macrophages and T cells in areas surrounding the necrotic core. At the ultrastructural level, immunogold electron microscopy confirmed the localization of TFPI in ECs, macrophages/foam cells, and SMCs. In ECs and SMCs, the gold particles decorated the plasmalemma proper and the caveolae. ELISA on cross sections revealed that atherosclerotic tissues contain more TFPI than do the healthy vessels. TFPI was functionally active against TF. FVIIa-induced coagulation, and its activity was higher in those tissues that display less TF. The largest amount of TFPI and TF were detected in complicated arterial plaques. By immunofluorescence, TFPI colocalized with platelet- and fibrin-rich areas within the organized thrombi. Atherosclerotic vessel sections promote activation of factor X, which is dependent on the presence of TF and enhanced by preincubation of the sections with anti-TFPI IgG. Taken altogether, our results suggest that TFPI is largely expressed in the normal vessel wall and enhanced in the atherosclerotic vessel, in a manner suggesting a significant role of TFPI in the regulation of TF activity.     

High-performance liquid chromatographic/mass spectrometric studies on the susceptibility of heparin species to cleavage by heparanase

Heparanase is an endo-beta-D-glucuronidase that cleaves the heparan sulfate chains of heparan sulfate proteoglycans and is implicated in angiogenesis and metastasis. With the aim of establishing a simple and reliable method for studying the susceptibility of heparin/heparan sulfate oligosaccharides to be cleaved by heparanase, an on-line ion pair reversed-phase high-performance liquid chromatographic/electrospray ionization mass spectrometric method was set up. The method works in the micromolar range of concentration and does not require derivatization of the substrate or of the products. It is based on mass identification of oligosaccharide fragments generated by heparanase and their quantification with reference to an internal heparin disaccharide standard. Substrates were (1) the synthetic pentasaccharides GlcN (NS,6S) - GlcA - GlcN (NS,3S,6S) - IdoA (2S) - GlcN (NS,6S) - OMe (AGA*IA (M)) and GlcN (NS,6S) - GlcA - GlcN (NS,6S) - IdoA (2S) - GlcN (NS,6S) - OMe (AGAIA (M)), corresponding to the heparin/heparan sulfate active site for antithrombin, and to the same sequence devoid of the 3- O-sulfate group in the central glucosamine, respectively; and (2) two natural heparin octasaccharides containing the AGA*IA sequence in different locations along the chain. The two pentasaccharides exhibited a higher susceptibility to heparanase cleavage with respect to the octasaccharides. The commercial availability of AGA*IA (M) makes it an ideal substrate to determine the specific activity of heparanase preparations. The present method could also be used for rapid screening of potential heparanase inhibitors.     

Inhibition of heparanase-mediated degradation of extracellular matrix heparan sulfate by non-anticoagulant heparin species

Incubation of human platelets, human neutrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase-mediated release of labeled heparan sulfate cleavage fragments (0.5 less than Kav less than 0.85 on Sepharose 6B). This degradation was inhibited by native heparin both when brought about by intact cells or their released heparanase activity. Degradation of heparan sulfate in ECM may facilitate invasion of normal and malignant cells through basement membranes. The present study tested the heparanase inhibitory effect of nonanticoagulant species of heparin that might be of potential use in preventing heparanase mediated extravasation of bloodborne cells. For this purpose, we prepared various species of low-sulfated or low-mol-wt heparins, all of which exhibited less than 7% of the anticoagulant activity of native heparin. N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the O-sulfate groups are retained. O-sulfate groups could be removed provided that the N positions were resulfated. Total desulfation of heparin abolished its heparanase inhibitory activity. Heparan sulfate was a 25-fold less potent heparanase inhibitor than native heparin. Efficiency of low-mol-wt heparins to inhibit degradation of heparan sulfate in ECM decreased with their main molecular size, and a synthetic pentasaccharide, representing the binding site to antithrombin III, was devoid of inhibitory activity. Similar results were obtained with heparanase activities released from platelets, neutrophils, and lymphoma cells. We propose that heparanase inhibiting nonanticoagulant heparins may interfere with dissemination of bloodborne tumor cells and development of experimental autoimmune diseases.     

Heparanase, galectin-3, and tissue factor mRNA are expressed in benign neoplasms of the thyroid

Objective: Heparanase, galectin-3, and tissue factor (TF) are overexpressed in solid malignant thyroid tumors. We studied their expression in multinodular goiters (MNGs). Design and Methods: Thyroid tissue specimens from 15 MNGs were obtained during surgery. mRNA expression for galectin-3, heparanase, and TF was assessed by RT-PCR. Results: Isolated expressions of heparanase and galectin-3 mRNA were expressed in 2 and 4 of the 15 MNGs, respectively; 8/15 MNGs were positive for both heparanase and galectin-3. TF mRNA was found in all MNG specimens. Conclusion: Galectin-3, heparanase, and TF RNA expression is prevalent in MNGs. Further studies will be needed to determine the prognostic significance of these findings.     

Heparanase expression correlates with malignant potential in human colon cancer

Purpose Heparanase cleaves carbohydrate chains of heparan sulphate proteoglycans and is an important component of the extracellular matrix. This study was designed to determine the relation between heparanase expression and prognosis of patients with colon cancer.Methods The study included 54 patients (35 males and 19 females) who underwent colorectal resection for colorectal cancer between January 1992 and December 1994. Expression of heparanase protein and mRNA were determined and correlated with various clinicopathological parameters. In vitro studies were also performed to examine tumor invasion and to test the effects of heparanase inhibition, and in vivo studies were performed to examine tumor metastasis and prognosis.Results Heparanase expression was detected in the invasion front of the tumor in 37 of 54 (69%) colon cancer samples, whereas 17 of 54 (31%) tumors were negative. Expression of heparanase was significantly more frequent in tumors of higher TNM stage (P=0.0481), higher Dukes stage (P=0.0411), higher vascular infiltration (P=0.0146), and higher lymph vessel infiltration (P=0.0010). Heparanase expression in colon cancers correlated significantly with poor survival (P=0.0361). Heparanase-transfected colon cancer cells exhibited significant invasion compared with control-transfected colon cancer cells (P=0.001), and the peritoneal dissemination model also showed the malignant potential of heparanase-transfected cells, as assayed by number of nodules (P=0.017) and survival (P=0.0062). Inhibition of heparanase significantly reduced the invasive capacity of cancer cells (P=0.003).Conclusions Heparanase is a marker for poor prognosis of patients with colon cancer and could be a suitable target for antitumor therapy in colon cancer.     

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. © 1996 Wiley-Liss, Inc.     

Heparanase-neutralizing antibodies attenuate lymphoma tumor growth and metastasis

Heparanase is an endoglycosidase that cleaves heparan sulfate side chains of proteoglycans, resulting in disassembly of the extracellular matrix underlying endothelial and epithelial cells and associating with enhanced cell invasion and metastasis. Heparanase expression is induced in carcinomas and sarcomas, often associating with enhanced tumor metastasis and poor prognosis. In contrast, the function of heparanase in hematological malignancies (except myeloma) was not investigated in depth. Here, we provide evidence that heparanase is expressed by human follicular and diffused non-Hodgkin''s B-lymphomas, and that heparanase inhibitors restrain the growth of tumor xenografts produced by lymphoma cell lines. Furthermore, we describe, for the first time to our knowledge, the development and characterization of heparanase-neutralizing monoclonal antibodies that inhibit cell invasion and tumor metastasis, the hallmark of heparanase activity. Using luciferase-labeled Raji lymphoma cells, we show that the heparanase-neutralizing monoclonal antibodies profoundly inhibit tumor load in the mouse bones, associating with reduced cell proliferation and angiogenesis. Notably, we found that Raji cells lack intrinsic heparanase activity, but tumor xenografts produced by this cell line exhibit typical heparanase activity, likely contributed by host cells composing the tumor microenvironment. Thus, the neutralizing monoclonal antibodies attenuate lymphoma growth by targeting heparanase in the tumor microenvironment.Heparanase is an endo-β-d-glucuronidase capable of cleaving heparan sulfate (HS) side chains at a limited number of sites, releasing saccharide products with appreciable size (4–7 kDa) and biological potency. Enzymatic degradation of HS leads to disassembly of the extracellular matrix (ECM) and correlates with the metastatic potential of tumor-derived cells, attributed to enhanced cell dissemination as a consequence of HS cleavage and remodeling of the ECM and basement membrane underlying epithelial and endothelial cells (1, 2). Heparanase expression is induced in human cancer, most often associating with reduced patients’ survival postoperation, increased tumor metastasis, and higher vessel density (3–5). In addition, heparanase up-regulation is associated with tumors larger in size (3, 5). Likewise, heparanase over-expression enhanced (6, 7), whereas local delivery of anti-heparanase siRNA inhibited (8), the growth of tumor xenografts. These results imply that heparanase function is not limited to tumor metastasis but is engaged in progression of the primary lesion, thus critically supporting the intimate involvement of heparanase in tumor progression and encouraging the development of heparanase inhibitors as anticancer therapeutics (9–12). As a consequence, heparanase inhibitors are currently evaluated in phase 1 clinical trials (13).Heparanase activity is similarly implicated in the progression of multiple myeloma (14–16), but its significance in other hematologic malignancies has not yet been characterized. Lymphomas are a heterogeneous group of cancers that arise from developing lymphocytes and produce tumors predominantly in lymphoid structures (i.e., bone marrow), but also in extranodal tissues. Collectively, lymphomas constitute the fifth most common cancer in North America, with more than 90% of the patients being affected by lymphomas of B-cell origin (17). Despite overall improvements in outcomes of lymphoma, ∼30–40% of patients have disease that is either refractory or relapses after standard therapy (18). Therefore, a better understanding of the molecular pathobiology of lymphomas is needed for the development of new therapeutic approaches. Here, we provide evidence that heparanase is expressed by B-lymphomas and that heparanase inhibitors restrain tumor growth. Furthermore, we describe the development of novel heparanase-neutralizing monoclonal antibodies (mAbs) that attenuate lymphoma growth by targeting heparanase in the tumor microenvironment.     

Discordant expression of tissue factor and its activity in polarized epithelial cells. Asymmetry in anionic phospholipid availability as a possible explanation.

Recent studies have shown a discrepancy between the level of tissue factor (TF) expression and the level of TF procoagulant activity on the apical and basolateral surface domains of polarized epithelial cells. The present investigation was performed to elucidate possible reasons for the discordant expression of TF and its activity on the surface of polarized epithelial cells using a human intestinal epithelial cell line, Caco-2 and Madin-Darby canine kidney epithelial cells, type II (MDCK-II). Functional activity of coagulation factor VIIa (VIIa) in complex with TF was 6- to 7-fold higher on the apical than the basolateral surface in polarized Caco-2 cells. In contrast, no significant difference was found in the formation of TF/VIIa complexes between the apical and basolateral surface. Confocal microscopy of Caco-2 cells showed TF expression on both the apical and the basolateral surface domains. Studies with MDCK-II cells showed that the specific functional activity of TF expressed on the apical cell surface was 5-fold higher than on the basolateral surface. To test whether differential expression of TF pathway inhibitor (TFPI) on the apical and basolateral surface could account for differences in TF/VIIa functional activity, we measured cell-surface-bound TFPI activity in Caco-2 cells. Small but similar amounts of TFPI were found on both surfaces. Further, addition of inhibitory anti-TFPI antibodies induced a similar enhancement of TF/VIIa activity on both surface domains. Because the availability of anionic phospholipids on the outer leaflet of the cell membrane could regulate TF/VIIa functional activity, we measured the distribution of anionic phospholipids on the apical and basolateral surface by annexin V binding and thrombin generation. The results showed that the anionic phospholipid content on the basolateral surface, compared with the apical surface, was 3- to 4-fold lower. Mild acid treatment of polarized Caco-2 cells, which markedly increased the anionic phospholipid content on the basolateral surface membrane, increased the TF/VIIa activity on the basolateral surface without affecting the number of TF/VIIa complexes formed on the surface. Overall, our data suggest that an uneven expression of TF/VIIa activity between the apical and basolateral surface of polarized epithelial cells is caused by differences in anionic phospholipid content between the two surface domains and not from a polar distribution of TFPI.     

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 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. Am. J. Hematol. 55:169–174, 1997. © 1997 Wiley-Liss, Inc.