Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this review we will discuss the possible interference of antiphospholipid antibodies with the protein C system. Antiphospholipid antibodies can interfere with the protein C system in different ways: (i) via inhibiting the formation of thrombin; (ii) via interference with the activation of protein C by the thrombomodulin-thrombin complex; (iii) via inhibition of the assembly of the protein C complex; (iv) via inhibition of the activity of protein C, directly or via its cofactor protein S, and (v) via antibodies directed against the substrates of APC, factors Va and VIIIa, thereby protecting them for inactivation. The experimental and theoretical indications that one of these mechanisms will explain the pathogenesis of the antiphospholipid syndrome is critically examined.
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PMID:Protein C and other cofactors involved in the binding of antiphospholipid antibodies: relation to the pathogenesis of thrombosis. 890 88

Patients with a family history of thrombosis, early-onset or recurring thrombosis, thrombosis at unusual sites, or warfarin-induced skin necrosis should be investigated for a possible underlying inherited hypercoagulable disorder. These include AT-III deficiency, protein C and S deficiencies, and APC resistance. Many patients should also be evaluated for the antiphospholipid syndrome, an acquired disorder. Functional assays are more useful than immunologic assays for diagnosing AT-III deficiency, protein C and S deficiencies, and APC resistance. A molecular probe is now available for the abnormal factor V most often responsible for APC resistance. Testing for the antiphospholipid syndrome involves assays for the lupus anticoagulant and anticardiolipin antibodies. AT-III and protein C concentrates are now available for short-term therapy. Long-term prophylactic administration of warfarin may have to be considered for some symptomatic patients with proven abnormalities, especially after more than one thrombotic event. While the management of asymptomatic persons remains controversial, the use of prophylactic anticoagulation should be anticipated for trauma, surgery, pregnancy, or other high-risk situations.
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PMID:The hypercoagulable state. Who, how, and when to test and treat. 915 17

Within the last few years, the knowledge of hereditary and acquired risk factors for venous thromboembolism has increased. Antithrombin-, protein C- and protein S-deficiency have been known since a long time as hereditary risk factors. Since 1993, three hitherto unknown risk factors have been described, the APC (activated protein C) resistance, hyperhomocysteinemia and a polymorphism in the 3-UT region of the prothrombin gene. These risk factors are relatively common in the normal population (in total 10-15%) and are found in 30-50% of patients with venous thromboembolism. The most important acquired risk factor for thromboembolism is the antiphospholipid antibody syndrome (APLS). The APLS is found in around 3% of patients with thromboembolism, patients with these abnormalities have a high risk for recurrency. The upper mentioned risk factors for thromboembolism do not only increase the risk for spontaneous thrombosis, but also the risk for thrombosis during typical high risk situations, such as surgery, trauma of the lower extremities, pregnancy and delivery. APC resistance and antithrombin deficiency increase the risk for development of thrombosis during oral contraceptive intake. Patients, in whom one of the upper mentioned risk factors have been diagnosed, should receive thrombosis prophylaxis during high risk situations. Not all patients with one thromboembolic event and a known risk factor are candidates for long-term oral anticoagulant treatment. Long-term oral anticoagulant treatment should be introduced after exclusion of major contraindications in patients with recurrent events, patients with a combination of risk factors and a life threatening event.
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PMID:[Thromboembolism--genetic and acquired risk factors]. 1047 76

Antiphospholipid antibodies are well recognized as associated with serious clinical complications such as arterial and venous thrombosis and recurrent spontaneous abortion. These complications are collectively called antiphospholipid syndrome(APS). The mechanisms responsible for the thrombosis are unclear. We reported three mechanisms. beta 2-glycoprotein I(beta 2GPI) inhibited activated protein C(APC) activity and, furthermore, APC activity decreased by the addition of monoclonal aCL and beta 2GPI. Monoclonal anticardiolipin antibodies(aCL) seemed to enhance the inhibition of APC procoagulant activity caused by beta 2GPI. Monoclonal aCL in the presence of beta 2GPI also increased the activity of plasminogen activator inhibitor(PAI)-1 in the mixture of tissue-plasminogen activator(t-PA) and PAI-1 by inhibiting the function of beta 2GPI, which increased the remaining t-PA activity in the mixture. The formation of thrombin-antithrombin complexes(TAT) in APS was impaired. The level of TAT in APS did not increase, however the level of prothrombin fragment 1 + 2 (F1 + 2) increased. Therefore, free thrombin present in patients' blood may contribute to thrombosis in APS. These reports indicate that thrombosis in APS may be caused by several thrombogenic factors that stimulate aCL.
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PMID:[Antiphospholipid antibodies and thrombosis: the putative mechanisms of hypercoagulable state in patients with anticardiolipin antibody]. 1081 Aug 73

We present the case of a 42-year-old female patient with the diagnoses of autoimmune hepatitis type I and autoimmune thyroiditis. Furthermore this patient had an unusual combination of coagulation disorders with homozygous Factor V Leiden mutation (APC resistance) and presence of antiphospholipid antibodies, leading to deep vein thromboses and miscarriages. Only few cases with the combination of autoimmune hepatitis and antiphospholipid antibodies have been described and almost all of them had become symptomatic with the antiphospholipid syndrome. As both autoimmune phenomenons furthermore share similar HLA-patterns, their coincidence is probably not as uncommon as the limited number of case reports suggests. Therefore attention in patients with autoimmune hepatitis should be focused on thrombophilia.
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PMID:Autoimmune hepatitis associated with coagulation disorders and immunethyreopathy. 1160 52

Inflammatory bowel diseases (IBD)--ulcerative colitis and Crohn's disease--are associated with increased risk for thrombotic complications both in the arterial and venous system. Cerebral sinus thrombosis is a rare but potentially fatal consequence of these diseases. Modern imaging methods made this uncommon complication of IBD more frequently recognized. The link between IBDs and thrombosis has been extensively studied. Inherited coagulation disorders (APC resistance, antithrombin III and protein-S deficiency), acquired diseases (antiphospholipid syndrome), and the frequent use of corticosteroids were suspected. Two cases of ulcerative colitis associated with cerebral sinus thrombosis successfully treated are reported. The connection between IBD and thrombotic complications and the therapeutic risks are discussed as well.
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PMID:[Cerebral sinus thrombosis and ulcerative colitis: two cases]. 1271 83

Over a 5-year period, we investigated 77 consecutive patients (36 males, 41 females, mean age 40.9 years) referred to our hospital with the diagnosis of CNS vasculitis. Extensive workup including MRI, echocardiography, laboratory tests, angiography ( n=53), and biopsies at appropriate sites ( n=26) was performed based on individual history and symptoms. Prominent symptoms were stroke ( n=61), encephalopathy ( n=14), and headaches ( n=2). Vasculitis was finally diagnosed in 13 patients (17%) including isolated angiitis of the CNS ( n=3), giant cell arteritis ( n=4), and septic arteritis ( n=3). Thirty-two patients (42%) presented noninflammatory vasculopathies including moyamoya ( n=6), Sneddon's syndrome ( n=5), dissection ( n=4), CADASIL ( n=2), and collagen vascular disease ( n=9). Coagulopathy was found in 14 cases (18%) including antiphospholipid syndrome ( n=8) and APC resistance ( n=4). Other causes were cardiogenic embolism ( n=8), multiple sclerosis ( n=5), and migraine stroke ( n=3). Only a minority of patients referred for evaluation of suspected CNS vasculitis actually present with inflammatory vascular disease. Main differential diagnosis includes noninflammatory vasculopathies, coagulopathies, and cardiac disease. Since septic processes may be responsible for the symptoms, "blind" treatment with immunosuppressive agents should be strictly avoided.
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PMID:[Diagnosis and differential cerebral vasculitis diagnosis]. 1477 Feb 79

Thrombophilia is a prothrombotic state that can be caused by genetic disorders, such as the factor-V-Leiden or prothrombin mutation, as well as by acquired changes like oestrogen-induced APC resistance and the antiphospholipid syndrome. Pregnancy induces multiple procoagulant changes in the haemostatic system, increasing the risk of venous thromboembolism in women with a thrombophilia even further. Additionally, thrombophilias are suggested to be associated with a number of pregnancy complications such as recurrent miscarriage, stillbirth, preeclampsia and HELLP syndrome. Increased local activation of coagulation may directly influence trophoblast expansion and invasion, causing thereby an impaired trophoblast development and insufficient widening of spiral arteries in the first trimenon, which results in placenta-mediated pregnancy complications like preeclampsia or HELLP syndrome. Besides, macro- and microthrombosis in the vessels of placental stemm villi and spiral arteries may lead to multiple infarctions with release of necrotic trophoblast fragments and inflammatory cytokines playing an important role in the pathogenesis of recurrent pregnancy loss and stillbirth. For women with a known thrombophilia it is recommended to carry out either only postpartal or combined ante- and postpartal thrombosis prophylaxis with low-molecular weight heparins (LMWH) depending on the individual risk stratification. The effectiveness of the LMWH administration for prevention of thrombophilia-induced pregnancy complications and improvement of the pregnancy outcome is currently a matter of debate. Furthermore, an additional application of acetyIsalicylic acid (ASA) should be considered in the management of women with the antiphospholipid antibody syndrome. In the current article we present the case of a 28-year-old woman with the heterozygous prothrombin mutation, HELLP syndrome, a late miscarriage and a stillbirth in the anamnesis, who delivered 3 healthy babies under antenatal LMWH prophylaxis combined with intensive interdisciplinary prenatal care.
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PMID:[Thrombophilia and HELLP syndrome in pregnancy - case report and overview of the literature]. 2573 77

Antiphospholipid syndrome (APS) is a systemic autoimmune disease, characterized by thrombosis, obstetric complications and the presence of antiphospholipid antibodies (aPL), which drive endothelial injury and thrombophilia. Extracellular vesicles (EVs) have been implicated in endothelial and thrombotic pathologies. Here, we characterized the quantity, cellular origin and the surface expression of biologically active molecules in small EVs (sEVs) isolated from the plasma of thrombotic APS patients (n = 14), aPL-negative patients with idiopathic thrombosis (aPL-neg IT, n = 5) and healthy blood donors (HBD, n = 7). Nanoparticle tracking analysis showed similar sEV sizes (110-170 nm) between the groups, with an increased quantity of sEVs in patients with APS and aPL-neg IT compared to HBD. MACSPlex analysis of 37 different sEV surface markers showed endothelial (CD31), platelet (CD41b and CD42a), leukocyte (CD45), CD8 lymphocyte and APC (HLA-ABC) cell-derived sEVs. Except for CD8, these molecules were comparably expressed in all study groups. sEVs from APS patients were specifically enriched in surface expression of CD62P, suggesting endothelial and platelet activation in APS. Additionally, APS patients exhibited increased CD133/1 expression compared to aPL-neg IT, suggesting endothelial damage in APS patients. These findings demonstrate enhanced shedding, and distinct biological properties of sEVs in thrombotic APS.
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PMID:Characterization of Plasma-Derived Small Extracellular Vesicles Indicates Ongoing Endothelial and Platelet Activation in Patients with Thrombotic Antiphospholipid Syndrome. 3241 70