Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute bilateral renal cortical necrosis is a very rare cause of acute renal failure. We report here for the first time a case related to antiphospholipid syndrome, paraneoplastic of a lung neoplasia. A 46-year-old male smoker without medical history was admitted for acute dyspnea and anuria. Biological examination showed acute renal failure associated with hyperkalemia, high serum lactate dehydrogenase level, and prolonged activated thrombin time (ratio 1.29). Chest radiograph showed a right laterotracheal round lesion. A percutaneous left renal biopsy showed cortical necrosis, and renal arteriography confirmed bilateral cortical necrosis. Blood examination showed antiphospholipid antibodies type anticardiolipin. Chest computed tomographic scan confirmed the presence of a lung tumor. Two years after tumor surgery, the patient was still anuric and on long-term hemodialysis therapy, but antiphospholipid antibody results were negative. This case describes the first association of antiphospholipid syndrome to epidermoid lung cancer, shown by cortical bilateral necrosis. It also emphasizes the utility of renal biopsy in case of an unusual acute renal failure.
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PMID:Renal cortical necrosis related to paraneoplastic antiphospholipid syndrome. 1673 3

Antiphospholipid Ab have been shown to promote thrombosis and fetal loss in the antiphospholipid syndrome (APS). Previously, we found IgG anti-thrombin Ab in some APS patients that could interfere with inactivation of thrombin by antithrombin (AT). Considering that activated coagulation factor X (FXa) is homologous to thrombin in the catalytic domains and is also regulated primarily by AT, we hypothesized that some thrombin-reactive Ab may bind to FXa and interfere with AT inactivation of FXa. To test these hypotheses, we studied reactivity of eight patient-derived monoclonal IgG antiphospholipid Ab with FXa and the presence of IgG anti-FXa Ab in APS patients and investigated the effects of FXa-reactive mAb on AT inactivation of FXa. The results revealed that six of six thrombin-reactive IgG mAb bound to FXa and that the levels of plasma IgG anti-FXa Ab in 38 APS patients were significantly higher than those in 30 normal controls (p < 0.001). When the mean plus 3 SDs of the 30 normal controls was used as the cutoff, 5 of 38 APS patients (13.2%) had IgG anti-FXa Ab. Importantly, three of six FXa-reactive mAb significantly inhibited AT inactivation of FXa. Combined, these results indicate that anti-FXa Ab may contribute to thrombosis by interfering with the anticoagulant function of AT on FXa in some APS patients.
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PMID:Antibodies against the activated coagulation factor X (FXa) in the antiphospholipid syndrome that interfere with the FXa inactivation by antithrombin. 1711 99

The combined presence of anti-phospholipid Ab (aPL), thrombosis, and/or fetal loss is recognized as the antiphospholipid syndrome (APS). aPL include anti-cardiolipin Ab (aCL) and/or lupus anticoagulants (LAC, detected as Ig that prolong certain in vitro phospholipid (PL)-restricted blood clotting tests); both aCL and LAC are the diagnostic Ab for APS. Studies show that aPL represent a heterogeneous group of Ab, which recognize various PL, PL-binding plasma proteins, and/or PL-protein complexes. Recently, we found that five of seven patient-derived IgG monoclonal aCL react with thrombin, activated protein C, and plasmin. All three proteins are trypsin-like serine proteases (SP), and are highly homologous in their catalytic domains. Importantly, among these SP autoantigens, the reactive aCL bind to plasmin with the highest affinity, suggesting that plasmin may serve as a major driving autoantigen for some aCL in approximately 30% of APS patients who are positive for IgG anti-plasmin Ab. To test this hypothesis, we immunized BALB/c mice with human plasmin and analyzed immune sera for aCL activity and reactivity with relevant SP. We found that some immune sera displayed aCL activity and/or bound to test SP. Subsequently, eight mAb were obtained and studied. The results revealed that one mAb displayed the aCL and the LAC activities and induced fetal loss when injected into pregnant mice. Immunohistological analyses of placentas revealed extensive deposits of activated C3 components. Combined, these data demonstrate that plasmin may serve as a driving Ag for some pathogenic aPL.
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PMID:Some plasmin-induced antibodies bind to cardiolipin, display lupus anticoagulant activity and induce fetal loss in mice. 1740 20

Antiphospholipid antibodies (aPL) constitute a heterogeneous group of autoantibodies that share the ability to bind phospholipids (PL) alone, protein-PL complexes, or PL-binding proteins. They have been detected in isolation, in association with autoimmune diseases such as systemic lupus erythematosus (SLE), and during the course of different infections. aPL have been associated with an array of clinical manifestations in virtually every organ, although deep vein and arterial thrombosis as well as pregnancy morbidity are predominant. The co-occurrence of these clinical findings with aPL constitutes the so-called antiphospholipid syndrome (APS). aPL can be detected by immunological methods [e.g., anticardiolipin antibodies (aCL)] or by functional methods that exploit the effect of aPL on blood coagulation [lupus anticoagulant (LA)]. Since aPL are heterogeneous, numerous immunological and coagulation assays have been developed. These assays have not been fully standardized, and, therefore, problems such as high interlaboratory variation are relatively frequent. Recently, recommendations have been published regarding LA and aCL testing. Not all aPL are pathogenic. However, when they are not associated with infections, they have a role in the pathogenesis of APS. Clinical and experimental data have shown that aPL exert their pathogenic activity by interfering with the function of coagulation factors, such as thrombin and factors X, XI and XII, and with the function of anticoagulant proteins of the protein C system. In addition, aPL interaction with platelets and endothelial cells induces a pro-adhesive activated phenotype.
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PMID:Antiphospholipid antibodies: laboratory and pathogenetic aspects. 1745 20

The antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterised by autoantibody production and vascular thrombosis or pregnancy morbidity. Autoantibodies generated against phospholipid and phospholipid-binding proteins often impair phospholipid-dependent clotting assays (lupus anticoagulants). These autoantibodies activate endothelial cells, platelets and biochemical cascades and can exist in autoimmune disorders such as lupus. Consistently positive antibodies may worsen the severity of thrombo-occlusive disease. The most common neurological manifestations of APS include stroke and transient ischaemic attacks due to arterial thromboses. Antiphospholipid antibodies may cause additional neurological impairments through both vascular and immune mechanisms. Antiaggregant or anticoagulant therapies are indicated for APS-related ischaemic strokes. Treatment regimens for asymptomatic antibody-positive patients and those with refractory disease remain controversial. There is scant literature on neurological APS manifestations in paediatric patients. Assessment of traditional cardiovascular and inherited thrombophilia risk factors is essential in patients with APS. Modifiable risk factors and valvular heart disease may worsen thrombotic and cerebrovascular outcomes. Alternative therapies such as statins, anti-malarials, angiotensin-converting enzyme inhibitors and thrombin inhibitors warrant further research.
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PMID:Neurological manifestations of the antiphospholipid syndrome: risk assessments and evidence-based medicine. 1759 87

We conducted an investigation to determine the antigenic determinants of antithrombin antibody (aThr), which has recently been recognized as a new antiphospholipid antibody mostly co-existing with antiprothrombin antibody, employing patients with systemic lupus erythematosus and antiphospholipid syndrome. Using an enzyme-linked immunosorbent assay we found aThr in 34 of 83 patients (40.9%), and 27 of these 34 patients (79.4%) with aThr were all negative for other antiphospholipid antibodies. An optical density value of six of 30 patients (20.0%) with aThr showed more than a 40% reduction of reactivity to thrombin with the addition of antithrombin in a dose-dependent manner. The inhibition percentage of aThr to thrombin was prominently increased to 11 of 30 (37%) along with its inhibition rate (100% at the highest) by the co-existence of heparin. Seven out of 30 patients with aThr (23.3%) showed a reduction of the optical density value with the addition of hirudin. Our findings suggest that aThr exists solely in patients with systemic lupus erythematosus without other antiphospholipid antibodies, and the antigenic determinants of aThr are directed to exosite I (hirudin binding site) and exosite II (antithrombin/heparin binding site) on the thrombin surface, with exosite II predominance. Accordingly, aThr could be an isolated and additional new marker of thrombosis/hemostasis. Since our patients who were positive only for aThr do not have a past history of antiphospholipid-associated complications at this stage, however, further long-term follow-up and additional studies in these clinical settings are needed to verify our hypothesis in the future.
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PMID:Sole existence of antithrombin antibody in patients with systemic lupus erythematosus showing tendency of its antigenic determinants directing against exosite II (antithrombin/heparin binding site) of thrombin. 1818 Jun 18

Experimental antiphospholipid syndrome (eAPS) induced by immunization with beta(2)-glycoprotein I (beta(2)-GPI) causes behavioral hyperactivity. We assessed the role of thrombotic and inflammatory perivascular factors and standard APS therapies for CNS manifestations. Groups of mice (n=10 per group) were immunized once with beta(2)-GPI (eAPS) or adjuvant (controls) and treated daily from 1 month after immunization with either sham injections, aspirin (1.2 mg/kg) or enoxaparin (1 mg/kg) for 3 months. Serum antiphospholipid antibodies (aPL) and brain levels of tissue necrosis factor-alpha (TNF-alpha) and prostaglandin E (PGE) were then measured by ELISA and thrombin inhibitors by immunoblot. Behavioral hyperactivity was assessed by the staircase test. The eAPS mice had higher levels of aPL than adjuvant immunized controls. Inflammatory markers were found to be twofold higher and intrinsic brain thrombin inhibitors 50% lower in eAPS brains compared to controls. aPL titers were unaffected by treatment. Both aspirin and enoxaparin normalized brain concentrations of PGE and TNF-alpha and elevated thrombin inhibitors, the latter effect being more pronounced for enoxaparin. The increased activity and rearing exploratory behavior in eAPS (138.6+/-13.6 and 141.9+/-13.9% of controls, respectively) were attenuated significantly more by treatment with enoxaparin (91.5+/-12.3 and 95.0+/-9.8%) than by aspirin (167.0+/-18.4 and 114.7+/-13.1%, p<0.01, ANOVA). Together, these results demonstrate that eAPS is associated with significant brain inflammation and thrombosis that are well treated with both standard therapies for human APS. Enoxaparin attenuates behavior better than aspirin possibly by reducing thrombosis or stabilization of the blood brain barrier, suggesting an advantage for similar drugs in CNS APS.
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PMID:Interaction of inflammation, thrombosis, aspirin and enoxaparin in CNS experimental antiphospholipid syndrome. 1830 78

Once the diagnosis of a thrombophilic state has been established, management must include one or more strategies designed to attenuate thrombotic risk and the likelihood of clinical events. In the case of drug-induced arterial thrombosis provoked by oral contraceptives, hormone replacement therapy, heparinoids, cocaine, or thienopyridine-related thrombotic thrombocytopenic purpura (TTP), the offending agent should be discontinued immediately. Anticoagulant therapy and platelet-directed therapies, either alone or in combination, should be considered for patients experiencing a single arterial or venous thrombosis (secondary prevention), with treatment duration determined by diagnostic studies and the persistence of a prothrombotic state. Other specific therapies should be directed at the underlying thrombophilic disorder. These treatments include direct thrombin inhibitors such as argatroban for heparin-induced thrombocytopenia (HIT), myelosuppressive drugs such as hydroxyurea for essential thrombocytosis, plasma exchange for thrombotic thrombocytopenic purpura, and phlebotomy for polycythemia vera. Additionally, the treating physician must seek input early from a hematologist or rheumatologist when managing patients with known or suspected HIT, TTP, and myeloproliferative disorders, or the antiphospholipid syndrome, respectively. This interdisciplinary interface is critical to ensure an optimal outcome when treating patients with arterial thrombophilia.
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PMID:Identification and treatment of arterial thrombophilia. 1832 2

Antiphospholipid syndrome is an autoimmune disorder in which the body produces antibodies to its own phospholipids or plasma proteins. Antiphospholipid syndrome (APS) is associated with many pathologies with several clinical manifestations. It can occur as a primary disorder or may be secondary to connective tissue disorder or tumor. Anti-phospholipid antibodies were detected in two categories of patients: in one group with many clinical manifestations (such as thrombotic events, thrombocytopenia and miscarriages) and in the other group with few clinical manifestations. In the first group high levels of IgG and IgA antibodies resulted, in the other group low levels of IgM. The ratio male:female was 1:3.5. Out of the 700 patients examined, 12 resulted positive for anti-cardiolipin (aCL) and a-beta2-GPI (affected by APS), and 15 patients positive for aCL (with middle-high values) but negative for a-beta2-GPI. At this point, according to the guidelines, we could have stopped examining. Only by continuing diagnostic investigation for these 15 patients has it been possible to observe: 2 patients positive for anti-thrombin (important first marker in the diagnosis of venose and arterial thromboses), anti-phosphatidylserine and anti-phosphatidylinositol (markers for cerebral diseases and recurrent miscarriages); 1 patient positive for anti- phosphatidylserine; 1 patient positive for anti-phosphatidylinositol antibody; 1 patient positive for both anti-phosphatidylserine and anti-phosphatidylinositol; 10 patients positive only for anti-cardiolipin. According to the results obtained, and considering that a more accurate investigation permitted to better identify APS syndrome, we propose a new diagnostic procedure.
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PMID:A new diagnostic approach to better identify antiphospholipid syndrome. 1854 83

Lupus anticoagulants (LAC) consist of antiphospholipid antibodies, detected via their anticoagulant properties in vitro. Strong LAC relate to thromboembolic events, a hallmark of the antiphospholipid syndrome. We have analyzed whether detection of this syndrome would benefit from thrombin generation measurements. Therefore, calibrated automated thrombography was done in normal plasma (n = 30) and LAC patient plasma (n = 48 non-anticoagulated, n = 12 on oral anticoagulants), diluted 1:1 with a normal plasma pool. The anti-beta2-glycoprotein I monoclonal antibody 23H9, with known LAC properties, delayed the lag time and reduced the peak height during thrombin generation induction in normal plasma dose-dependently (0-150 microg/ml). At variance, LAC patient 1:1 plasma mixtures manifested variable lag time prolongations and/or peak height reductions. Coupling these two most informative thrombin generation parameters in a peak height/lag time ratio, and upon normalization versus the normal plasma pool, this ratio distributed normally and was reduced in the plasma mixtures, for 59/60 known LAC plasmas. The normalized peak height/lag time ratio correlated well with the normalized dilute prothrombin time, diluted Russell's viper venom time and silica clotting time, measured in 1:1 plasma mixtures (correlation coefficients 0.59-0.72). The anticoagulant effects of activated protein C (0-7.5 nM) or 23H9 (0-150 microg/ml), spiked in the 1:1 LAC plasma mixtures were reduced for the majority of patients, compatible with functional competition between patient LAC and activated protein C and LAC and 23H9, respectively. Hence, the normalized thrombin generation-derived peak height/lag time ratio identifies LAC in plasma with high sensitivity in a single assay, irrespective of the patient's treatment with oral anticoagulants.
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PMID:Laboratory detection of the antiphospholipid syndrome via calibrated automated thrombography. 1913 7


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