RESUMO
Povidone-iodine (PVP-I) has been widely used as an antiseptic agent during invasive procedures for prenatal diagnosis. Women have been reported of thyroid dysfunction after simple exposure to PVP-I. We studied the effect on thyroid function and urinary iodine excretion after a single topical application of PVP-I in 31 women who had a miscarriage during the first trimester of pregnancy. PVP-I is absorbed through the skin and the vaginal mucosa, resulting in a sudden increase in the urinary excretion of iodine and a short-term variation in concentrations of thyroid hormones in maternal serum. This metabolic effect could have consequences for the embryo and the fetus during crucial stages of development.
Assuntos
Aborto Espontâneo/cirurgia , Anti-Infecciosos Locais/efeitos adversos , Dilatação e Curetagem , Povidona-Iodo/efeitos adversos , Complicações na Gravidez/induzido quimicamente , Doenças da Glândula Tireoide/induzido quimicamente , Anti-Infecciosos Locais/farmacocinética , Anti-Infecciosos Locais/urina , Feminino , Humanos , Povidona-Iodo/farmacocinética , Gravidez , Primeiro Trimestre da Gravidez , Estudos Prospectivos , Tireotropina/metabolismo , Tiroxina/metabolismoRESUMO
In the last few years, it has become clear that the processes of tumor angiogenesis, metastasis and invasiveness are highly dependent on components of the blood coagulation cascade. One of the key proteins in coagulation is tissue factor (TF). In addition, TF is also known as a mediator of intracellular signaling events that can alter gene expression patterns and cell behavior. TF significantly participates in tumor-associated angiogenesis and its expression levels have been correlated with the metastatic potential of many types of hematological malignancies. Signaling pathways initiated by both, tissue factor-activated factor VII (TF-FVIIa) protease activation of protein-activated receptors (PARs), and phosphorylation of the TF-cytoplasmic domain, appear to regulate these tumoral functions. Advances in antiangiogenic therapies and preclinical studies with TF-targeted therapeutics are hopeful in the control of tumor growth and metastasis, but continued studies on the regulation of TF are still needed. In the last few years, the use of approaches of functional genomics and proteomics has allowed the discovery of new proteins involved in the origin of the neoplasia and their participation in the development of the disease. This review attempts to establish a cellular and molecular causal link between cancer coagulopathy, angiogenesis and tumor progression in hematological malignancies.
Assuntos
Neoplasias Hematológicas/fisiopatologia , Neovascularização Patológica/etiologia , Tromboplastina/fisiologia , Animais , Progressão da Doença , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/patologia , Humanos , Leucemia/fisiopatologia , Metástase Neoplásica , Proteômica , Transdução de Sinais , Tromboplastina/análise , Tromboplastina/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/análise , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidoresRESUMO
The current mainstay of treatment in patients with thrombotic antiphospholipid syndrome (APS) is long-term anticoagulation, mainly with Vitamin K antagonist agents. Some recently available studies have created new ground for discussion about the possible discontinuation of anticoagulation therapy in patients with a history of thrombotic APS in whom antiphospholipid antibodies (aPL) are not detected any longer (i.e. aPL seroconversion). We report the main points discussed at the last CORA Meeting regarding the issue whether or not anticoagulation can be stopped after aPL seroconversion. In particular, we systematically reviewed the available evidence investigating the clinical outcome of APS patients with aPL seroconversion in whom anticoagulation was stopped when compared to those in whom therapy was continued regardless the aPL profile. Furthermore, the molecular basis for the aPL pathogenicity, the available evidence of non-criteria aPL and their association with thrombosis are addressed. To date, available evidence is still limited to support the indication to stop oral anticoagulation therapy in patients with a previous diagnosis of thrombotic APS who subsequently developed a negative aPL profile. The identification of the whole risk profile for cardiovascular manifestations and possibly of a second level aPL testing in selected patients with aPL might support the eventual clinical decision but further investigation is warranted.
Assuntos
Anticorpos Antifosfolipídeos/imunologia , Anticoagulantes/uso terapêutico , Síndrome Antifosfolipídica/tratamento farmacológico , Soroconversão/efeitos dos fármacos , Trombose/tratamento farmacológico , Síndrome Antifosfolipídica/imunologia , Humanos , Prognóstico , Fatores de Risco , Trombose/imunologiaRESUMO
BACKGROUND: One of the described mechanisms leading to thrombosis in antiphospholipid syndrome (APS) is overexpression of tissue factor (TF) in the monocytes and endothelial cells of patients with antiphospholipid antibodies (aPL). Vascular endothelial growth factor (VEGF) may stimulate monocyte TF expression through its receptor, the tyrosine kinase Flt-1. OBJECTIVES: This study aimed to analyze the following in monocytes of 55 primary APS patients: VEGF and Flt-1 expression levels, their potential regulation by aPL, and the association of VEGF and Flt-1 expression with the increased TF expression found in APS patients. RESULTS: Purified monocytes from APS patients showed higher levels of VEGF and Flt-1 than healthy donors, which further correlated with immunoglobulin G (IgG) anticardiolipin titers and TF expression rank. Moreover, monocyte VEGF and Flt-1 levels were significantly higher in patients with than in patients without previous thrombosis. In vitro, IgG from APS patients increased monocyte VEGF and Flt-1 expression in a dose-dependent manner. VEGF and Flt-1 expression was significantly inhibited by the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580; this suggests the involvement of this kinase in the aPL-induced VEGF and Flt-1 upregulation. CONCLUSIONS: Our data show, for the first time in vivo, that monocytes from primary APS patients have an increased expression of VEGF and Flt-1. Furthermore, in vitro results indicated that this cytokine is produced by monocytes when treated with aPL, and that the p38 MAPK signaling pathway plays an important role. Thus, VEGF might act as a regulatory factor in aPL-mediated monocyte activation and TF expression, thereby contributing to the proinflammatory-prothrombotic phenotype of APS patients.
Assuntos
Síndrome Antifosfolipídica/metabolismo , Regulação da Expressão Gênica , Sistema de Sinalização das MAP Quinases , Monócitos/metabolismo , Tromboplastina/biossíntese , Fator A de Crescimento do Endotélio Vascular/biossíntese , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/biossíntese , Adolescente , Adulto , Idoso , Síndrome Antifosfolipídica/patologia , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Imidazóis/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Monócitos/patologia , Piridinas/farmacologia , Trombose/metabolismo , Trombose/patologia , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidoresRESUMO
Acute promyelocytic leukaemia (APL) may be associated with disseminated intravascular coagulation, as a result of increased tissue factor (TF) expression and reduced thrombomodulin (TM) expression by APL blast cells. During retinoid acid (RA)- and dibutyryl cAMP (dbcAMP)-induced differentiation of the APL cells, there is a marked up-modulation of both the protein kinase A (PKA) and C (PKC) activities. In order to further assess whether these kinases are intimately associated with both the differentiation process and the regulation of TF and TM expression, we have correlated the modulation of their respective pathways with the extent of differentiation and modulation of these cellular receptors. NB4 cells were incubated with all-trans-RA (ATRA) or dbcAMP for up to 48 h. The contribution of phospholipase C (PLC), inositol phosphate (IP), PKC and PKA in the expression of CD11b, TF and TM was studied by the use of specific inhibitors. Myo-inositol uptake and PKC activity increased in cells induced to differentiate by ATRA but the retinoid did not affect cAMP levels or PKA activity. Under treatment with dbcAMP, PKA activity was increased while inositol uptake and PKC activity remained unchanged. Our results show that the effects of ATRA and dbcAMP on promyelocytic cells are closely related, respectively, to the PLC/IP/PKC and the cAMP/PKA pathways. In cells induced to differentiate by ATRA, CD11b expression seems more closely related to inositol uptake than to PKC activity while the expression of TF and TM show the opposite pattern, which suggests cellular events regulated at a different level within a common signal transduction pathway.
Assuntos
Granulócitos/efeitos dos fármacos , Transdução de Sinais , Trombomodulina/metabolismo , Tromboplastina/metabolismo , Bucladesina/farmacologia , Diferenciação Celular/efeitos dos fármacos , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/farmacologia , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Granulócitos/citologia , Granulócitos/metabolismo , Humanos , Leucemia Promielocítica Aguda/metabolismo , Antígeno de Macrófago 1/efeitos dos fármacos , Antígeno de Macrófago 1/metabolismo , Proteína Quinase C/metabolismo , Proteína Quinase C/farmacocinética , Proteína Quinase C/fisiologia , Trombomodulina/efeitos dos fármacos , Tromboplastina/efeitos dos fármacos , Tretinoína/farmacologia , Células Tumorais CultivadasRESUMO
Tissue factor (TF) and urokinase receptor (uPAR) are key cellular receptors triggering, respectively, coagulation and fibrinolysis. Bleeding complications among leukemic patients have been related to an abnormal expression of TF by blast cells and/or to an abnormal fibrinolytic response. In this study the expression of TF and uPAR has been assessed in 18 acute non-lymphoblastic and 8 lymphoblastic leukemic blast cells using several methodological approaches. TF mRNA was evaluated by in situ hybridization and TF and uPAR antigen were evaluated immunologically in cell lysates and on the cell surface by flow cytometry. In addition, TF-procoagulant activity was measured in coagulation-based assays. The reliability of these methods was corroborated in six leukemic cell lines of different lineages and states of maturation. Disseminated intravascular coagulation was detected in two M3 leukemia patients whose blast cells expressed high amounts of TF. Hyperfibrinolysis was detected in one M1 and two M2 patients, whose blast cells displayed a high content of uPAR antigen, but no TF. Furthermore, M5 leukemia blast cells expressed both TF and uPAR, although no hemostatic defects or bleeding complications were detected in these patients. Taken together, although a limited number of patients was included in this study, these data suggest that in leukemia patients exhibiting bleeding, either TF or uPAR are expressed by their blast cells. However, the presence of these receptors does not necessarily imply the existence of a hemostatic disorder.
Assuntos
Hemorragia/etiologia , Leucemia/sangue , Receptores de Superfície Celular/metabolismo , Tromboplastina/metabolismo , Doença Aguda , Coagulação Sanguínea , Humanos , Leucemia/complicações , Receptores de Ativador de Plasminogênio Tipo Uroquinase , Células Tumorais CultivadasRESUMO
The urinary type plasminogen activator, urokinase (uPA) is localized on the cell surface through the binding of a specific receptor, the uPA receptor (uPAR). The uPA localization enhances plasmin formation on the cell surface and facilitates cell migration. The cellular and tissue distribution of uPAR is not fully established. We have analyzed uPAR expression in nine leukemic cell lines of distinct lineages and maturational states and correlated this with expression of plasminogen receptors, tissue-type plasminogen activator (tPA) receptors and LDL receptor-related protein (LRP). The most immature and least differentiated cell line (an erythro-myeloid cell line) and cells of lymphoid lineage, did not express uPAR, whereas cells differentiated along the myelo-monocytic pathway displayed this receptor. Plasminogen and tPA receptors were expressed by all leukemic cell lines and by all nucleated peripheral blood cells but B and T lymphocytes were negative for cell surface expression of both uPAR and LRP while monocytes and neutrophils were positive for expression of both uPAR and LRP. PMA stimulation induced surface expression of uPAR in lymphocytes but did not induce expression of LRP by these cells. In contrast, lymphoid cell lines were negative for uPAR expression even after PMA stimulation, indicating differences in regulation of uPAR expression between lymphocytes and lymphoid cell lines. The pattern of uPAR expression on leukemic cell lines was also studied on bone marrow blast cells from leukemic patients. Only the most mature myeloid cells expressed uPAR on their surfaces. In contrast, M3 leukemic cells and other blast cells displaying lymphoid markers such as TdT (+) and/or CD2 (+) did not express intracellular or cell-surface associated uPAR, indicating an heterogeneity among these promyelocytic cells and suggesting that uPAR may be a useful marker for leukemia typing. Myeloid blast cells from some patients contained intracellular pools of uPAR but displayed no receptor on the cell surface, suggesting that translocation may be a mechanism regulating uPAR expression in these cells. The comparison of uPAR expression between these cell lines and peripheral blood cells and it correlation with plasminogen receptors, tPA receptors and LRP expression offers new insights regarding potential mechanisms for regulation of uPA-uPAR-mediated pericellular proteolysis.
Assuntos
Leucemia/metabolismo , Leucócitos Mononucleares/metabolismo , Receptores de Superfície Celular/biossíntese , Diferenciação Celular , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica , Humanos , Leucemia/patologia , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Receptores Imunológicos/biossíntese , Receptores de Ativador de Plasminogênio Tipo Uroquinase , Ativador de Plasminogênio Tecidual , Células Tumorais CultivadasRESUMO
Antiphospholipid antibodies (aPL) may stimulate tissue factor (TF) expression in cultured endothelial cells and monocytes, but there are discrepancies as to the expression of TF in the patients with antiphospholipid syndrome (APS). By using reverse transcription and polymerase chain reaction amplification, we have analysed TF mRNA accumulation in freshly isolated mononuclear blood cells (MBC) of 14 patients with primary APS (PAPS) and six normal controls. TF mRNA accumulation was low or absent in uncultured MBC from all normal controls, but was elevated in uncultured MBC from nine of the patients as well as in normal MBC incubated with 100 ng/ml lipopolysaccharide (LPS). Mean levels of TF mRNA, as measured by densitometry, were higher in MBC from patients (N = 14) than in those from controls (N = 6, P = 0.009), and in MBC from patients with a history of thrombosis (N = 9) than in those from patients without thrombosis (N = 5, P = 0.02). Uncultured MBC of patients with thrombosis accumulated TF mRNA at similar levels to LPS-treated normal MBC. Increased levels of TF mRNA were found in eight of ten patients with conventional aPL (ie, anti-cardiolipin antibodies [aCL] and/or lupus anticoagulant [LA]) and little if any accumulation of TF mRNA was observed in three of four patients without aPL at the time of study. These data strongly suggest that circulating monocytes of many patients with PAPS are subjected to an up-regulated TF expression that may well explain their prothrombotic state. Although the presence or absence of TF mRNA in MBC was associated with, respectively, the presence or absence of conventional aPL in 11 of the 14 patients studied, our study cannot exclude the involvement of factors other than aCL or LA in inducing TF expression.
Assuntos
Síndrome Antifosfolipídica/sangue , Leucócitos Mononucleares/metabolismo , Tromboplastina/metabolismo , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , RNA Mensageiro/metabolismoRESUMO
OBJECTIVE: To determine the relation between thrombopoietin (Tpo) levels following orthotopic liver transplantation (OLT), cold ischemia time and postoperative peripheral blood platelet count and prothrombin activity. DESIGN: Prospective clinical study. SETTING: Intensive care unit. PATIENTS: Fourteen patients with uncomplicated postoperative course after OLT. MEASUREMENTS AND RESULTS: Plasma Tpo, as quantified by enzyme immunoassay, rose significantly from 194.9 +/- 45.7 pg/ml on day 1 after OLT to a peak value of 500.7 +/- 94.1 pg/ml on day 5 while platelet count was below normal values. Then the platelet count increased and reached normal values while Tpo decreased to normal. The rise of Tpo levels was associated with normalization of prothrombin time but peak Tpo concentrations were in inverse correlation with cold ischemia times. CONCLUSION: The extent of production of Tpo in the liver graft following OLT is affected by cold ischemia time. This observation may be applicable in the prevention of bleeding complications associated with postoperative thrombocytopenia.
Assuntos
Isquemia/patologia , Transplante de Fígado , Contagem de Plaquetas , Tempo de Protrombina , Trombopoetina/sangue , Adulto , Análise de Variância , Temperatura Baixa , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Preservação de Órgãos , Fatores de TempoRESUMO
The antiphospholipid syndrome (APS) was reported in the early 1980s as the association of thrombosis, recurrent pregnancy loss in the presence of anticardiolipin antibodies (aCL) and/or lupus anticoagulant (LA). Since then, many other clinical manifestations have been associated with aPL. Almost any organ and tissue may be involved in the disease, including the brain, the heart, the kidneys, the placenta and many more. aPL are a heterogeneous group of autoantibodies that are detected by immunoassays and functional coagulation tests. The antigenic targets are negatively charged phospholipids and serum phospholipid-binding proteins. Despite the strong association between aPL and thrombosis, the pathogenic role of aPL in the development of thrombosis has not been fully elucidated. Proposed mechanisms include antibody-mediated interference with coagulation homeostasis, activation of platelets and endothelial cells and a T-cell immune response to serum phospholipid-binding proteins. The mainstay of therapy is anticoagulation, whereas immunosuppression seems to be ineffective. Recommendations for the management of thrombosis in the antiphospholipid antibody syndrome have been based largely on retrospective case series. Several prospective clinical trials are currently underway and their results will probably lead to a more precise therapeutic approach of this problem.
Assuntos
Síndrome Antifosfolipídica , Aborto Habitual/etiologia , Aborto Habitual/prevenção & controle , Síndrome Antifosfolipídica/classificação , Síndrome Antifosfolipídica/diagnóstico , Síndrome Antifosfolipídica/fisiopatologia , Síndrome Antifosfolipídica/terapia , Feminino , Fibrinolíticos/uso terapêutico , Humanos , Gravidez , Complicações na Gravidez/fisiopatologia , Trombose/etiologiaRESUMO
Nitric oxide (NOË) is a short-lived, endogenously produced gas that is highly diffusible across cell membranes and acts as a signaling molecule in the body. The redox state and chemistry of NOË facilitate its interaction with various proteins thus regulating various intracellular and intercellular events. One of the key mechanisms by which NOË regulates the function of various target proteins is through the coupling of a nitroso moiety from NO-derived metabolites to a reactive cysteine leading to the formation of a S-nitrosothiol (SNO), a process commonly known as S-nitrosylation. S-nitrosylation signaling events within the cell have led to the discovery of many other physiological functions of NOË in many other types of cells including cancer cells. Only recently are the diverse roles of S-nitrosylation in cancer beginning to be understood. In the present review we discuss the recent evidence for the diverse roles of NOË/SNO-related mechanisms in cancer biology and therapy, including the participation of NOË in the pathogenesis of cancer, its duality in protecting against or inducing cancer cell death and the contribution of NOË to metastatic processes. In addition, NOË can be therapeutically used in the reversal of tumor cell resistance to cytotoxic drugs and as a sensitizing agent to chemo- and radiotherapy. Finally, recent studies providing evidence for NO-related mechanisms of epigenetic gene expression regulation will also be discussed. Undoubtedly, new exciting results will contribute to this rapidly expanding area of cancer research.
Assuntos
Antineoplásicos/metabolismo , Cisteína/metabolismo , Neoplasias/metabolismo , Óxido Nítrico/metabolismo , Processamento de Proteína Pós-Traducional , Animais , Antineoplásicos/uso terapêutico , Apoptose , Epigênese Genética , Humanos , Neoplasias/irrigação sanguínea , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Óxido Nítrico/uso terapêutico , Óxido Nítrico Sintase/metabolismo , Transdução de Sinais , Microambiente TumoralRESUMO
BACKGROUND: Tissue factor (TF) is the main initiator of the coagulation cascade and elements that may upregulate its expression might provoke thrombotic events. Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are autoimmune diseases characterized by a high TF expression in monocytes. OBJECTIVES: To examine the role of microRNAs (miRNAs) in TF expression and to evaluate their levels in SLE and APS patients. METHODS: An in silico search was performed to find potential putative binding sites of miRNAs in TF mRNA. In vitro validation was performed transfecting cells expressing TF (THP-1 and MDA-MB-231) with oligonucleotide miRNA precursors and inhibitors. Additionally, reporter assays were performed to test for the binding of miR-20a to TF mRNA. Levels of miRNAs and TF were measured by quantitative (qRT-PCR) in patients with APS and SLE. RESULTS: Overexpression of miRNA precursors, but not inhibitors, of two of the members of cluster miR-17â¼92, for example miR-19b and miR-20a, in cells expressing TF decreased TF mRNA, protein levels, and procoagulant activity between 30% and 60%. Reporter assays showed that miR-20a binds to TF mRNA. Finally, we measured levels of miR-19b and miR-20a in monocytes from patients with APS and SLE and observed significantly lower miRNAs levels in comparison with healthy subjects inversely correlated with the levels of TF. CONCLUSIONS: Down-regulation of miR-19b and miR-20a observed in patients with SLE and APS could contribute to increased TF expression and thus provoke the hypercoagulable state characteristic of these patients.
Assuntos
Síndrome Antifosfolipídica/metabolismo , Lúpus Eritematoso Sistêmico/metabolismo , MicroRNAs/fisiologia , Tromboplastina/metabolismo , Adulto , Idoso , Western Blotting , Estudos de Casos e Controles , Linhagem Celular , Feminino , Humanos , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Several systemic autoimmune conditions, including rheumatoid arthritis, systemic lupus erythematosus and antiphospholipid syndrome, are characterised by enhanced atherosclerosis and, consequently, higher cardiovascular morbidity and mortality rates. The association of these diseases with atherosclerosis suggests a common pathogenic mechanism. Genomic and proteomic studies performed on atherosclerotic plaques have further confirmed the presence of a gene and protein profile similar to that observed in autoimmune diseases with cardiovascular risks. Human sera and body fluids have been analysed and have resulted in the identification of auto-antibodies that can be used as diagnostic markers in specific autoimmune diseases, and proteomic fingerprints of blood cells, tissues and body fluids have resulted in the identification of individual proteins or patterns of protein expression that are deregulated. The information provided by these proteomic studies is of diagnostic and therapeutic potential. In this review, we discuss new approaches available for assessing thrombotic risk in autoimmune diseases, focusing in the genomic and proteomic methods now available to deep into the origin of the mechanisms associated with vascular involvement in systemic autoimmune diseases. The increasing data available suggests that when treating patients with these autoimmune disorders, paying attention to the increased risk of cardiovascular disease is essential.
Assuntos
Doenças Autoimunes/complicações , Doenças Autoimunes/genética , Doenças Cardiovasculares/etiologia , Genômica , Proteômica , Doenças Autoimunes/patologia , Doenças Cardiovasculares/patologia , Técnicas Genéticas , Humanos , Medição de RiscoRESUMO
The endothelial cell line ECV304 is a spontaneously transformed cell line established from human umbilical vein. The characterization of tissue factor (TF) expression by ECV304 cells has been accomplished in this study. ECV304 cells expressed both TF mRNA and antigen (TFag) constitutively. In ECV304 cell lysates, the levels of TFag (1.4+/-0.3 ng of TFag/10[6] cells) were considerably higher than in THP-1 monocytoid cells (0.07+/-0.03 ng of TFag/10[6] cells). TFag was also detected on the ECV304 cell surface by flow cytometric studies. In binding analyses, 3.5+/-0.7 x 10(4) molecules of TF per cell were estimated, similar to the amounts found in ECV304 cell lysates (2.9+/-0.6 x 10(4) molecules/cell), suggesting that all TFag was translocated to the cell surface. Phorbol myristate acetate (PMA) stimulation of ECV304 cells resulted in an increase of TF mRNA levels, which was abrogated when gene transcription was impaired, suggesting a transcriptional regulation of the TF gene by PMA. In contrast, TFag was not elevated by PMA-stimulation, indicating the existence of additional posttranscriptional mechanisms. Thus, ECV304 cells constitute a singular endothelial cell model for exploring the regulation of TF expression.
Assuntos
Endotélio Vascular/metabolismo , Tromboplastina/metabolismo , Anticorpos Monoclonais , Linhagem Celular , Membrana Celular/metabolismo , Ácido Edético/farmacologia , Endotélio Vascular/citologia , Humanos , Monócitos/metabolismo , RNA Mensageiro/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Tromboplastina/genética , Fatores de TempoRESUMO
OBJECTIVE: The antiphospholipid syndrome (APS) is a disorder of recurrent thrombosis, pregnancy loss, and thrombocytopenia associated with the production of anticardiolipin antibodies (aCL) and lupus anticoagulant (LAC). The mechanisms of thrombus formation remain unknown. Tissue factor (TF), an inducible cell glycoprotein, is a major initiator of coagulation in vivo. The present study was therefore undertaken to investigate TF expression and procoagulant activity on monocytes from patients with primary APS and its correlation with thrombotic events. METHODS: Three groups of patients were studied: group 1 comprised 23 primary APS patients with thrombosis, group 2 consisted of 10 primary APS patients without thrombosis, and group 3 contained 20 patients with thrombosis but without antiphospholipid antibodies. Twenty age- and sex-matched healthy blood donors were used as controls (group 4). Anticardiolipin antibodies were measured by enzyme-linked immunosorbent assay (ELISA) and LAC by standard methodology. Cell surface expression of TF on monocytes was assessed by flow cytometry. The amount of TF in cell lysates (TF(Ag)) and soluble TF(Ag) plasma levels were analyzed by ELISA, and the TF-related procoagulant activity (PCA-TF) on intact cells and cell lysates by a chromogenic assay. Levels of the cytokines that influence TF production, i.e., tumor necrosis factor alpha (TNF alpha) and interleukin-1beta (IL-1beta), were determined by ELISA. RESULTS: Cell surface expression of TF was increased in group 1 (mean +/- SEM 50.2 +/- 4% positive cells) compared with group 2 (14.6 +/- 1.6%), group 3 (16.8 +/- 3.7%), and group 4 (14.1 +/- 1.6%). TF(Ag) levels were also elevated in group 1 (215.8 +/- 11.2 pg/10(6)) compared with group 2 (150.8 +/- 15.2), group 3 (101.4 +/- 14.8), and group 4 (80.32 +/- 5.5). PCA-TF on intact cells and cell lysates was significantly increased in group 1 (148.8 +/- 16.3 units/10(5) lysate cells, compared with 54.5 +/- 11.5, 38.6 +/- 9.7, and 22.5 +/- 3.1 in groups 2, 3, and 4, respectively). Among group 1 patients, there was a significant increase in the degree of TF expression in those positive for IgG aCL, but not in those positive for IgM aCL or LAC. TNF alpha and IL-1beta plasma levels did not differ significantly between any of the groups. CONCLUSION: These results suggest that monocyte TF expression is directly involved in the pathogenesis of thrombotic complications in patients with the primary APS.