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

Cardioprotective role of royal jelly in the prevention of celecoxib-mediated cardiotoxicity in adult male albino rats

BACKGROUND

Celecoxib, a cyclooxygenase-2 selective inhibitor non-steroidal anti-inflammatory drugs, is used for the management of short- and long-term pain as well as in other inflammatory conditions. Unfortunately, its chronic use is highly associated with serious abnormal cardiovascular events. The current study was designed to explore the effect of long-term administration of celecoxib on the cardiac tissues of male albino rats. The study also examined the alleged cardioprotective effect of royal jelly.

METHODS

Thirty, male albino rats were randomly divided into 3 equal groups; 10 each: (1) rats served as the control group and received no drug; (2) rats received celecoxib (50 mg/kg/day, orally), for 30 consecutive days; (3) rats received celecoxib (50 mg/kg/day, orally) plus royal jelly (300 mg/kg/day, orally) for 30 consecutive days. Sera were collected to assay cardiac enzymes and oxidant/antioxidant status. Rats were euthanatized and cardiac tissues were dissected for quantitative estimation of apoptotic genes (Bax) and anti-apoptotic gene (Bcl-2).

RESULTS

Long-term celecoxib administration caused cardiotoxicity in male albino rats as manifested by significant elevation of serum levels of creatine phosphokinase (CPK), creatine kinase-MB (CK-MB), and lactate dehydrogenase (LDH), with ameliorative effects of royal jelly against celecoxib-induced cardiotoxicity as manifested by significantly decrease in serum CPK, CK-MB, and LDH levels. It also showed a significant decrease in the oxidative stress indicator malondialdehyde (MDA) levels and the bax gene. Additionally, it demonstrated significant increases in the bcl-2 gene and superoxide dismutase (SOD) levels, which contribute to its therapeutic effects against celecoxib-induced cardiotoxicity.

CONCLUSION

Long-term celecoxib administration caused cardiotoxicity in male albino rats with protective effect of royal jelly being given together. It could be concluded that royal jelly may prove a useful adjunct in patients being prescribed celecoxib.

TRIAL REGISTRATION

Not applicable.

Biomaterials to Prevent Post-Operative Adhesion

Surgery is performed to treat various diseases. During the process, the surgical site is healed through self-healing after surgery. Post-operative or tissue adhesion caused by unnecessary contact with the surgical site occurs during the normal healing process. In addition, it has been frequently found in patients who have undergone surgery, and severe adhesion can cause chronic pain and various complications. Therefore, anti-adhesion barriers have been developed using multiple biomaterials to prevent post-operative adhesion. Typically, anti-adhesion barriers are manufactured and sold in numerous forms, such as gels, solutions, and films, but there are no products that can completely prevent post-operative adhesion. These products are generally applied over the surgical site to physically block adhesion to other sites (organs). Many studies have recently been conducted to increase the anti-adhesion effects through various strategies. This article reviews recent research trends in anti-adhesion barriers.

Protection of tight junction between RPE cells with tissue factor targeting peptide

AIM

To investigate the effect of tissue factor targeting peptide (TF-TP) on retinal pigment epithelium (RPE) cells tight junctions.

METHODS

Cell counting kit-8 (CCK-8) was used to measure the proliferation of ARPE-19 cells. Expression of tight junction, ZO-1 in ARPE-19 cells was measured by Western blot and immunofluorescent staining. Western blot was also used to detect the expression of tissue factor (TF). CEC Transmigration Assay was used to measure the migration of ARPE-19 cells. The transport of fluorescent markers [fluorescein isothiocyanate dextrans of 4, 10, 20 (FD4, FD10, FD20)] and the transepithelial electrical resistance (TEER) were used to measure in ARPE-19 cell.

RESULTS

CCK-8 assay showed that 5 µmol/L TF-TP can inhibit ARPE-19 cells abnormally proliferation stimulated by lipopolysaccharide (LPS; P<0.05). LPS increased the transport of fluorescent markers (FD4, FD10, FD20) and decreased TEER levels in ARPE-19 cells, respectively, which were prevented by 5 µmol/L TF-TP pretreatment (P<0.05). Furthermore, LPS significantly up-regulated the expression of TF and downregulated the expression of ZO-1 (P<0.05) in ARPE-19 cell which was inhibited by the TF-TP (P<0.05). In addition, TF-TP inhibited the abnormal migration induced by LPS in ARPE-19 cell (P<0.05).

CONCLUSION

Our findings suggest that TF-TP suppressed proliferation and migration of ARPE-19 cells induced by LPS, and maintained the RPE tight junctions through inhibition of TF expression and increased expression of ZO-1.

Erythrocyte deformability and eryptosis during inflammation, and impaired blood rheology

OBJECTIVE

This review focusses on the erythrocytes (RBCs) and their structural changes during inflammation and impaired blood rheology. We discuss systemic inflammation and the effects of dysregulated inflammatory molecules. These pro-inflammatory molecules directly affect the haematological system, and particularly the RBCs, platelets and plasma proteins. We focus on the three main changes; increased RBC eryptosis (programmed cell death, similar to apoptosis) and pathological deformability, platelet hyperreactivity and anomalous blood clotting, due to pathological changes to fibrin(ogen) protein structure. This pro-inflammatory haematological system directly affects blood rheology. In turn, hemorheological parameters such as RBC deformability are important parameters in hypercoagulation, which is a hallmark of inflammation. For RBC deformation to happen during blood flow, the RBC membrane needs to be elastic to elongate sufficiently to squeeze through small capillaries. However, of greater importance is that the cell must return to its original biconcave shape after exiting the small diameter capillaries.

CONCLUSION

Hemorheological parameters such as RBC deformability are of great importance clinically, to both identify the presence and extent of inflammation, and to study these parameters during intervention therapies. RBC rheology and deformability may therefore be a useful cell model for pharmaceutical testing.

Amaranth peptides decreased the activity and expression of cellular tissue factor on LPS activated THP-1 human monocytes

The immunomodulatory activity of amaranth peptides is linked for the first time with their antithrombotic activity. Inhibition of tissue factor expression and the NF-κB pathway was observed after treatment with the peptides.

The role of mononuclear cell tissue factor and inflammatory cytokines in patients with chronic thromboembolic pulmonary hypertension

Thrombosis and inflammation are two major factors underlying chronic thromboembolic pulmonary hypertension (CTEPH). Tissue factor (TF), C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein 1 (MCP-1) may play critical roles in the process of CTEPH thrombosis and pulmonary vascular remodeling. Ten patients with a confirmed diagnosis of CTEPH, 20 patients with acute pulmonary thromboembolism and 15 patients with other types of pulmonary hypertension were enrolled in this study, along with 20 healthy subjects as the control group. The immunoturbidimetric method was used to determine the plasma content of CRP. The plasma levels of TNF-α, MCP-1, and TF antigen were measured by an enzyme-linked immunosorbent assay, and TF activity was measured by the chromogenic substrate method. Percoll density gradient centrifugation was used to separate peripheral blood mononuclear cells from plasma. The level of monocyte TF mRNA was examined by reverse transcriptase-polymerase chain reaction. The correlations between all indices described above were analyzed. In CTEPH patients, the expression of CRP, TNF-α, and MCP-1 was significantly higher than that in controls (P < 0.05). The levels of TF activity, TF antigen, and TF mRNA in monocyte cells were increased in CTEPH patients when compared with control subjects, but only the TF antigen and TF mRNA levels were significantly different (P < 0.05). In CTEPH patients, levels of CRP, MCP-1, and TNF-α significantly correlated with the level of TF antigen in plasma. TF gene expression was increased in patients with CTEPH, suggesting that blood-borne TF mainly comes from mononuclear cells. TF expression significantly correlated with levels of CRP, TNF-α and MCP-1. These factors may play an important role in the development of CTEPH via the inflammation–coagulation–thrombosis cycle.

Evening primrose oil or forskolin ameliorates celecoxib-enhanced upregulation of tissue factor expression in mice subjected to lipopolysaccharide-induced endotoxemia

Celecoxib, a selective cyclooxygenase-2 inhibitor, produces thrombotic events in patients predisposed to cardiovascular risk factors. One theory reported an increase in endothelial expression of tissue factor (TF) as a predisposing factor. This work explored the effect of evening primrose oil (EPO), a source of prostaglandin E1, and forskolin (a cyclic adenosine monophosphate stimulator) against the prothrombotic effect of celecoxib in mice. Lipopolysaccharide mouse model of endotoxemia was used to induce an upregulation of TF activity. Male mice received celecoxib (25 mg/kg), celecoxib plus EPO, or celecoxib plus forskolin for 4 weeks and then subjected to a prothrombotic challenge in the form of an intraperitoneal injection of lipopolysaccharide. Results showed an increase in plasma TF activity, endothelial TF expression, and thrombin-antithrombin (TAT) but lower antithrombin III (ATIII) level in mice that received celecoxib in comparison to those that received the vehicle. Adding EPO or forskolin to celecoxib regimen significantly decreased the prothrombotic effect of celecoxib. A positive correlation (r = 0.8501) was found between TF activity and TAT. Co-administration of EPO or forskolin decreased the activity of TF and mitigated the prothrombotic effect of celecoxib. Therefore, these combinations may have the utility to abrogate the prothrombotic adverse effect of celecoxib in clinical setting.

Kinetics of lung tissue factor expression and procoagulant activity in bleomycin induced acute lung injury

Background

Activation of coagulation by expression of tissue factor (TF) in the airspace is a hallmark of acute lung injury (ALI) but the timing of TF activation in relationship to increases in lung permeability and inflammation are unknown.

Methods

To test the hypothesis that TF is upregulated early in the course of acute bleomycin lung injury and precedes increased permeability and inflammation we studied the early course of bleomycin-induced ALI in mice. Mice were treated with 0.04U intratracheal bleomycin or vehicle control and bronchoalveolar lavage (BAL) and lung tissue were collected daily for 7 days. Whole lung TF mRNA was determined by QT-PCR. TF protein was assessed by ELISA and immunostaining. BAL procoagulant activity was measured by BAL clot time and thrombin-antithrombin complexes. Inflammation was assessed by BAL cell count, differentials and CXCL1/KC concentration. Lung permeability was assessed by BAL protein and lung wet to dry weight ratio.

Results

Expression of CXCL1 occurred by day 1. BAL protein and lung wet-to-dry weight ratio increased significantly by day 3. TF mRNA and BAL procoagulant activity peaked on day 4 while whole lung TF protein peaked on day 6. Changes in permeability and procoagulant activity preceded inflammatory cell influx which was maximal at day 6 while whole lung TF protein peaked along with inflammation.

Conclusion

These data demonstrate that cytokine upregulation is the earliest response to bleomycin administration, followed by increased lung permeability, upregulation of TF, and recruitment of inflammatory cells.

Genetic determined low response to thienopyridines is associated with higher systemic inflammation in smokers

AIM

To investigate whether the interactions of CYP2C19*2 and CYP2C19*17 with smoking are associated with the levels of P2Y12 receptor inhibition and CRP, in on-thienopyridine post-stenting patients.

METHODS & RESULTS

At 1-month follow-up, the interactions of smoking and CYP2C19 polymorphisms on the vasodilator-stimulated phosphoprotein - platelet reactivity index (VASP PRI), and CRP were explored in three metabolizing groups (1128 patients) as follow: poor metabolizers (*2 carriers/*17 noncarriers); intermediate metabolizers (*2 carriers/*17 carriers or *2 noncarriers/*17 noncarriers); and ultrarapidmetabolizers (*2 allele noncarriers/*17 carriers). The interactions of metabolizing status and smoking was significant for CRP (p = 0.001) but not for VASP PRI (p = 0.734).

CONCLUSION

Interaction between CYP2C19 polymorphisms and smoking modifies on-treatment CRP level of post-stenting, on-thienopyridine patients. This effect seems to be independent to the level of P2Y12 receptor inhibition.

MicroRNA-223 inhibits tissue factor expression in vascular endothelial cells

OBJECTIVE

Atherosclerosis is a chronic inflammatory process, in which vascular endothelial cells (ECs) become dysfunctional owing to the effects of chemical substances, such as inflammatory factor and growth factors. Tissue factor (TF) expression is induced by the above chemical substances in activated ECs. TF initiates thrombosis on disrupted atherosclerotic plaques which plays an essential role during the onset of acute coronary syndromes (ACS). Increasing evidences suggest the important role of microRNAs as epigenetic regulators of atherosclerotic disease. The aim of our study is to identify if microRNA-223 (miR-223) targets TF in ECs.

METHODS AND RESULTS

Bioinformatic analysis showed that TF is a target candidate of miR-223. Western blotting analysis revealed that tumor necrosis factor α (TNF-α) increased TF expression in aorta of C57BL/6J mice and cultured ECs (EA.hy926 cells and HUVEC) after 4 h treatment. In TNF-α treated ECs, TF mRNA was also increased measured by real-time PCR. Real-time PCR results showed that miR-223 levels were downregulated in TNF-α-treated aorta of C57BL/6J mice and cultured ECs. Transfection of ECs with miR-223 mimic or miR-223 inhibitor modified TF expression both in mRNA and protein levels. Luciferase assays confirmed that miR-223 suppressed TF expression by binding to the sequence of TF 3'-untranslated regions (3'UTR). TF procoagulant activity was inhibited by overexpressing miR-223 with or without TNF-α stimulation.

CONCLUSIONS

MiR-223-mediated suppression of TF expression provides a novel molecular mechanism for the regulation of coagulation cascade, and suggests a clue against thrombogenesis during the process of atherosclerotic plaque rupture.

Effect of quercetin-rich onion peel extracts on arterial thrombosis in rats

The aim of this study was to examine whether oral supplementation of quercetin-rich onion peel extract (OPE) influences blood coagulation and arterial thrombosis in Sprague-Dawley (SD) rats. 24 male rats, 5 weeks old, were divided into three groups with different diets (C: control, 2mg OPE: chow diet with 2mg OPE supplementation, 10mg OPE: chow diet with 10mg OPE supplementation) for 6 weeks. Blood coagulation parameters including prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelet aggregation were examined. The OPE did not affect blood cholesterol levels but significantly decreased blood triglyceride and glucose levels. PT, aPTT and platelet aggregation were not significantly different among all tested groups. However, in vivo arterial thrombosis was significantly delayed in groups that were fed 2mg and 10mg OPE diets compared to the control group. In addition, the OPE greatly diminished thrombin-induced expression of tissue factor in human umbilical vein endothelial cells (HUVECs), a coagulation initiator. In addition, extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways activated by thrombin treatment were prevented by the OPE pre-treatment. These results indicate that OPE may have anti-thrombotic effects through restricting the induced expression of tissue factor via down-regulating mitogen-activated protein kinase (MAPK) activation upon coagulation stimulus, leading to the prolongation of time for arterial thrombosis.

The European Registry on Obstetric Antiphospholipid Syndrome (EUROAPS): a preliminary first year report

BACKGROUND

Obstetric morbidity (OM) is a common feature of antiphospholipid syndrome (OAPS). Women having OAPS-only and women with OM related to antiphospholipid antibodies (aPL) but not fulfilling APS classification criteria (OMAPS), may show similar patterns.

AIM

The aim of this research was to collect records of OAPS and OMAPS cases in order to have valuable information about their clinical features, laboratory, treatment, pregnancy outcomes and long-term follow-up.

METHODS

EUROAPS/EUROMAPS is a registry in the frame of the European Forum on Antiphospholipid Antibody projects. Its own website has been available since June 2010: www.euroaps.org.

RESULTS

This registry comprises 211 women including 304 pre-enrolment pregnancies, and 226 prospective cases, 194 of OAPS and 32 of OMAPS. OM was more frequent in OAPS than in OMAPS, independent of treatment. In the prospective cohort, standard aPL data was available in 202 cases and treatment data in all 226 cases. Good fetal outcomes were obtained when low dose aspirin plus low molecular weight heparin were administered. Prevalence of thrombotic events and/or cases evolving into full-blown systemic lupus erythematosus (SLE) was low.

CONCLUSIONS

OAPS could be a different form of APS. OMAPS/OMAPS fetal outcomes were better when treated. The prevalence of thrombosis and progression to SLE were lower than in 'classical' APS.

Enhancement of proinflammatory and procoagulant responses to silica particles by monocyte-endothelial cell interactions

BACKGROUND

Inorganic particles, such as drug carriers or contrast agents, are often introduced into the vascular system. Many key components of the in vivo vascular environment include monocyte-endothelial cell interactions, which are important in the initiation of cardiovascular disease. To better understand the effect of particles on vascular function, the present study explored the direct biological effects of particles on human umbilical vein endothelial cells (HUVECs) and monocytes (THP-1 cells). In addition, the integrated effects and possible mechanism of particle-mediated monocyte-endothelial cell interactions were investigated using a coculture model of HUVECs and THP-1 cells. Fe₃O₄ and SiO₂ particles were chosen as the test materials in the present study.

RESULTS

The cell viability data from an MTS assay showed that exposure to Fe₃O₄ or SiO₂ particles at concentrations of 200 μg/mL and above significantly decreased the cell viability of HUVECs, but no significant loss in viability was observed in the THP-1 cells. TEM images indicated that with the accumulation of SiO₂ particles in the cells, the size, structure and morphology of the lysosomes significantly changed in HUVECs, whereas the lysosomes of THP-1 cells were not altered. Our results showed that reactive oxygen species (ROS) generation; the production of interleukin (IL)-6, IL-8, monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor (TNF)-α and IL-1β; and the expression of CD106, CD62E and tissue factor in HUVECs and monocytes were significantly enhanced to a greater degree in the SiO₂-particle-activated cocultures compared with the individual cell types alone. In contrast, exposure to Fe₃O₄ particles had no impact on the activation of monocytes or endothelial cells in monoculture or coculture. Moreover, using treatment with the supernatants of SiO₂-particle-stimulated monocytes or HUVECs, we found that the enhancement of proinflammatory response by SiO₂ particles was not mediated by soluble factors but was dependent on the direct contact between monocytes and HUVECs. Furthermore, flow cytometry analysis showed that SiO₂ particles could markedly increase CD40L expression in HUVECs. Our data also demonstrated that the stimulation of cocultures with SiO₂ particles strongly enhanced c-Jun NH2-terminal kinase (JNK) phosphorylation and NF-κB activation in both HUVECs and THP-1 cells, whereas the phosphorylation of p38 was not affected.

CONCLUSIONS

Our data demonstrate that SiO₂ particles can significantly augment proinflammatory and procoagulant responses through CD40-CD40L-mediated monocyte-endothelial cell interactions via the JNK/NF-κB pathway, which suggests that cooperative interactions between particles, endothelial cells, and monocytes may trigger or exacerbate cardiovascular dysfunction and disease, such as atherosclerosis and thrombosis. These findings also indicate that the monocyte-endothelial cocultures represent a sensitive in vitro model system to assess the potential toxicity of particles and provide useful information that may help guide the future design and use of inorganic particles in biomedical applications.

Tissue factor, blood coagulation, and beyond: an overview

Emerging evidence shows a broad spectrum of biological functions of tissue factor (TF). TF classical role in initiating the extrinsic blood coagulation and its direct thrombotic action in close relation to cardiovascular risks have long been established. TF overexpression/hypercoagulability often observed in many clinical conditions certainly expands its role in proinflammation, diabetes, obesity, cardiovascular diseases, angiogenesis, tumor metastasis, wound repairs, embryonic development, cell adhesion/migration, innate immunity, infection, pregnancy loss, and many others. This paper broadly covers seminal observations to discuss TF pathogenic roles in relation to diverse disease development or manifestation. Biochemically, extracellular TF signaling interfaced through protease-activated receptors (PARs) elicits cellular activation and inflammatory responses. TF diverse biological roles are associated with either coagulation-dependent or noncoagulation-mediated actions. Apparently, TF hypercoagulability refuels a coagulation-inflammation-thrombosis circuit in “autocrine” or “paracrine” fashions, which triggers a wide spectrum of pathophysiology. Accordingly, TF suppression, anticoagulation, PAR blockade, or general anti-inflammation offers an array of therapeutical benefits for easing diverse pathological conditions.

The missing link between atherosclerosis, inflammation and thrombosis: is it tissue factor?

Acute thrombus formation on disrupted atherosclerotic plaques plays a key role during the onset of acute coronary syndromes. Lesion disruption facilitates the interaction between circulating blood and prothrombotic substances, such as tissue factor (TF) present within the atherosclerotic lesion. For a long period of time, vessel-wall TF has been considered the major determinant of thrombosis. However, this old dogma has been recently changed owing to the discovery of a different pool of TF that circulates in flowing blood (blood-borne TF). Several studies have shown that blood-borne TF circulates in different pools that are associated with selected blood cells, such as monocytes, granulocytes and platelets in cell-derived microparticles, and as a soluble protein generated by alternative splicing of its full-length mRNA. Recent studies have identified a hypercoagulable state associated with an increased circulating TF activity, leading to the concept of 'vulnerable blood'. Part of the blood-borne TF circulates in an 'inactive' form and it is required to be 'activated' to exert its thrombogenic potential. Certain pathological conditions, such as smoking, hyperlipidemia and diabetes, show a higher incidence of thrombotic complications. These conditions are also characterized by the presence of high levels of circulating TF activity. Recent evidence may also suggest that an increased circulating TF activity may potentiate the initial thrombogenic stimulus represented by vessel wall-associated TF, leading to the formation of larger and/or more stable thrombus, and thus more severe acute coronary syndromes. It has been reported that inflammation increases TF expression and activity by different cell types. On the other hand, TF upregulation may facilitate inflammation by enhancing intravascular fibrin deposition, formation of proinflammatory fragments of fibrin, and by generating coagulation proteases, including FVIIa, FXa and thrombin, that activate protease-activated receptors. Furthermore, the biology of TF is know known to be more complex than previously thought by the demonstration that this protein, apart from its known effects on blood coagulation, can also function as a signaling receptor.

Granulocyte-CSF induced inflammation-associated cardiac thrombosis in iron loading mouse heart and can be attenuated by statin therapy

Background

Granulocyte colony-stimulating factor (G-CSF), a hematopoietic cytokine, was recently used to treat patients of acute myocardial infarction with beneficial effect. However, controversy exists as some patients developed re-stenosis and worsened condition post G-CSF delivery. This study presents a new disease model to study G-CSF induced cardiac thrombosis and delineate its possible mechanism. We used iron loading to mimic condition of chronic cardiac dysfunction and apply G-CSF to mice to test our hypothesis.

Methods and Results

Eleven out of fifteen iron and G-CSF treated mice (I+G) showed thrombi formation in the left ventricular chamber with impaired cardiac function. Histological analysis revealed endothelial fibrosis, increased macrophage infiltration and tissue factor expression in the I+G mice hearts. Simvastatin treatment to I+G mice attenuated their cardiac apoptosis, iron deposition, and abrogated thrombus formation by attenuating systemic inflammation and leukocytosis, which was likely due to the activation of pAKT activation. However, thrombosis in I+G mice could not be suppressed by platelet receptor inhibitor, tirofiban.

Conclusions

Our disease model demonstrated that G-CSF induces cardiac thrombosis through an inflammation-thrombosis interaction and this can be attenuated via statin therapy. Present study provides a mechanism and potential therapy for G-CSF induced cardiac thrombosis.

Evidence for enhanced tissue factor expression in age-related macular degeneration

Tissue factor (TF) is the primary initiator of blood coagulation. In addition to hemostasis, TF can initiate intracellular signaling and promote inflammation and angiogenesis, the key processes underlying the pathogenesis of age-related macular degeneration (AMD). AMD, the leading cause of irreversible blindness among the elderly, involves many genetic and environmental risk factors, including oxidative stress and inflammation. In this study, TF expression was examined in human AMD tissue and in the eyes of a model of AMD, the Ccl2(-/-)/Cx3cr1(-/-) (DKO) mouse, as well as in the ARPE-19 cell line after lipopolysaccharide (LPS) and H(2)O(2) stimulation. Total RNA was extracted from tissue samples and further analyzed by real-time RT-PCR. Immunohistochemistry was performed to evaluate TF protein expression. In the human retina, a 32-fold increase of TF mRNA expression was detected in AMD macular lesions compared with normal maculae. TF protein expression was also enhanced in human AMD maculae. Similarly, TF transcript and protein expression were moderately increased in retinal lesions, neuroretinal tissue, and cultured RPE cells of DKO mice compared with age-matched wild-type mice. TF expression level correlated with age in both wild-type and DKO mice. In order to better understand how AMD might lead to enhanced TF expression, 1, 5, and 10 μg/ml LPS as well as 100 and 200 μM H(2)O(2) were used to stimulate ARPE-19 cells for 24 and 2 h, respectively. LPS treatment consistently increased TF transcript and protein expression. H(2)O(2) alone or in combination with LPS also moderately enhanced TF expression. These results indicate that upregulated TF expression may be associated with AMD, and inflammatory and oxidative stress may contribute to TF expression in AMD eyes.

Tissue factor in antiphospholipid antibody-induced pregnancy loss: a pro-inflammatory molecule

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

Blood coagulation, inflammation, and malaria

Malaria remains a highly prevalent disease in more than 90 countries and accounts for at least 1 million deaths every year. Plasmodium falciparum infection is often associated with a procoagulant tonus characterized by thrombocytopenia and activation of the coagulation cascade and fibrinolytic system; however, bleeding and hemorrhage are uncommon events, suggesting that a compensated state of blood coagulation activation occurs in malaria. This article (i) reviews the literature related to blood coagulation and malaria in a historic perspective, (ii) describes basic mechanisms of coagulation, anticoagulation, and fibrinolysis, (iii) explains the laboratory changes in acute and compensated disseminated intravascular coagulation (DIC), (iv) discusses the implications of tissue factor (TF) expression in the endothelium of P. falciparum infected patients, and (v) emphasizes the procoagulant role of parasitized red blood cells (RBCs) and activated platelets in the pathogenesis of malaria. This article also presents the Tissue Factor Model (TFM) for malaria pathogenesis, which places TF as the interface between sequestration, endothelial cell (EC) activation, blood coagulation disorder, and inflammation often associated with the disease. The relevance of the coagulation-inflammation cycle for the multiorgan dysfunction and coma is discussed in the context of malaria pathogenesis.

Tissue factor: a link between C5a and neutrophil activation in antiphospholipid antibody induced fetal injury

Fetal loss in patients with antiphospholipid (aPL) antibodies has been ascribed to thrombosis of placental vessels. However, we have shown that inflammation, specifically activation of complement with generation of the anaphylotoxin C5a, is an essential trigger of fetal injury. In this study, we analyzed the role of the procoagulant molecule tissue factor (TF) in a mouse model of aPL antibody-induced pregnancy loss. We found that either blockade of TF with a monoclonal antibody in wild-type mice or a genetic reduction of TF prevented aPL antibody-induced inflammation and pregnancy loss. In response to aPL antibody-generated C5a, neutrophils express TF potentiating inflammation in the deciduas and leading to miscarriages. Importantly, we showed that TF in myeloid cells but not fetal-derived cells (trophoblasts) was associated with fetal injury, suggesting that the site for pathologic TF expression is neutrophils. We found that TF expression in neutrophils contributes to respiratory burst and subsequent trophoblast injury and pregnancy loss induced by aPL antibodies. The identification of TF as an important mediator of C5a-induced oxidative burst in neutrophils in aPL-induced fetal injury provides a new target for therapy to prevent pregnancy loss in the antiphospholipid syndrome.

Up-regulation of tissue factor in human pulmonary artery endothelial cells after ultrafine particle exposure

BACKGROUND

Epidemiology studies have linked exposure to pollutant particles to increased cardiovascular mortality and morbidity, but the mechanisms remain unknown.

OBJECTIVES

We tested the hypothesis that the ultrafine fraction of ambient pollutant particles would cause endothelial cell dysfunction.

METHODS

We profiled gene expression of human pulmonary artery endothelial cells (HPAEC) exposed to ultrafine particles (UFPs; 100 microg/mL) from Chapel Hill, North Carolina, or vehicle for 4 hr with Affymetrix HG U133 Plus 2.0 chips (n = 4 each).

RESULTS

We found 320 up-regulated genes and 106 down-regulated genes (p < 0.01, 5% false discovery rate). We noted up-regulation of genes related to coagulation [tissue factor (F3) and coagulation factor II receptor-like 2 (F2RL2)] and differential regulation of genes related to F3 signaling (FOS, JUN, and NFKBIA). Results of quantitative polymerase chain reaction show a significant up-regulation of F3 after 10 and 100 microg/mLUFP exposures. Additionally, the water-soluble fractions of UFPs were sufficient to induce the expression of F3, F2RL2, and heme oxygenase 1 (HMOX1). Treatment of HPAEC with UFPs for 16 hr increased the release of interleukin (IL)-6 and IL-8. Pretreatment of HPAEC with a blocking antibody against F3 attenuated IL-6 and IL-8 release by 30 and 70%, respectively.

CONCLUSIONS

Using gene profiling, we discovered that UFPs may induce vascular endothelial cells to express genes related to clotting. These results indicate that PM may cause adverse cardiovascular health effects by activating coagulation-inflammation circuitry.

Pathogenesis, clinical and laboratory aspects of thrombosis in cancer

The relationship between increased clotting and malignancy is well recognized, though the bidirectional development of this association is often overlooked. In the challenging cancer biology, transforming genes often act in concert with numerous epigenetic factors, including hypoxia, inflammation, contact between blood and cancer cells, and emission of procoagulant vesicles from tumors, to determine a net imbalance of the hemostatic potential which is detectable by a variety of laboratory tests. Procoagulant factors, in particular, are intimately involved in all aspects of hemostatic, cell proliferation and cellular signalling systems. However, the biggest as yet unresolved question is why cancer patients develop thrombosis? Since the thrombus itself does not apparently contributes directly to the tumor biology, enhanced hemostasis activation in cancer patients may be interpreted according to the most recent biological evidences. Coagulation and cancer biology interact bidirectionally in a "vicious cycle", in which greater tumor burden supplies greater procoagulants (tissue factor, cancer procoagulant) and thrombin, which would in turn act as strong promoters of cancer growth and spread. In this perspective, thrombosis may be interpreted as a epiphenomenon of an intricate an effective biological feedback to maintain or promote cancer progression. In this review article, we briefly analyze the pathogenesis, laboratory, clinical and therapeutic features of cancer and thrombosis.