Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thrombotic microangiopathies are a group of microvascular disorders, with reduced organ perfusion and hemolytic anemia. The two most relevant conditions characterized by thrombotic microangiopathic anemia (TMA) are thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). In TTP, systemic microvascular aggregation of platelets causes ischemia in the brain and other organs. In HUS, platelet-fibrin thrombi predominantly occlude the renal circulation. TTP can be inherited due to deficiencies in the activity of von Willebrand factor cleaving protease (ADAMTS13) or acquired due to the presence of autoantibodies directed against ADAMTS13. The majority of HUS cases are secondary to infections by strains of Escherichia coli that produce Shiga-like toxins (Stx-HUS), while about 5- 10% of all cases are classified as atypical HUS (aHUS). Genetically derived impaired regulation of the complement system is associated with aHUS. Infusion or the exchange of fresh frozen plasma have ameliorated the prognosis of TMA; however, no specific therapies aimed at preventing or limiting the microangiopathic process have been proven to affect the course of TMA. Large mammals, small animal models, knockout and transgenic mouse models of TTP and both Stx-HUS and aHUS have been developed and have provided outstanding contributions to nearly all areas of TMA research. A better understanding of the key clinical features of the diseases and of the importance of genetic and/or environmental factors involved in the pathogenesis of the diseases have been obtained. These animal models have also allowed the set up of protocols aimed at ameliorating the clinical approach to patients and for the development of new drugs and vaccines.
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PMID:Thrombotic microangiopathies: from animal models to human disease and cure. 2125 31

Thrombotic thrombocytopenic purpura (TTP) is a rare but severe disease characterized by mechanical hemolytic anemia and consumptive thrombocytopenia leading to disseminated microvascular thrombosis that causes signs and symptoms of organ ischemia and functional damage. After the elucidation of the pathophysiology of TTP, thanks to the demonstration of the congenital or acquired (autoimmune) plasma deficiency of the von Willebrand factor cleaving metalloprotease A Disintegrin And Metalloprotease with ThromboSpondin 1 repeats (ADAMTS13), a number of laboratory assays for measuring ADAMTS13 and related autoantibodies have been developed. Current knowledge on the diagnostic and prognostic value of ADAMTS13 and anti-ADAMTS13 assays is summarized in this review.
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PMID:Advantages and limits of ADAMTS13 testing in the prognostic assessment of thrombotic thrombocytopenic purpura. 2224 22

Epidemiologic studies suggest that elevated VWF levels and reduced ADAMTS13 activity in the plasma are risk factors for myocardial infarction. However, it remains unknown whether the ADAMTS13-VWF axis plays a causal role in the pathophysiology of myocardial infarction. In the present study, we tested the hypothesis that ADAMTS13 reduces VWF-mediated acute myocardial ischemia/reperfusion (I/R) injury in mice. Infarct size, neutrophil infiltration, and myocyte apoptosis in the left ventricular area were quantified after 30 minutes of ischemia and 23.5 hours of reperfusion injury. Adamts13(-/-) mice exhibited significantly larger infarcts concordant with increased neutrophil infiltration and myocyte apoptosis compared with wild-type (WT) mice. In contrast, Vwf(-/-) mice exhibited significantly reduced infarct size, neutrophil infiltration, and myocyte apoptosis compared with WT mice, suggesting a detrimental role for VWF in myocardial I/R injury. Treating WT or Adamts13(-/-) mice with neutralizing Abs to VWF significantly reduced infarct size compared with control Ig-treated mice. Finally, myocardial I/R injury in Adamts13(-/-)/Vwf(-/-) mice was similar to that in Vwf(-/-) mice, suggesting that the exacerbated myocardial I/R injury observed in the setting of ADAMTS13 deficiency is VWF dependent. These findings reveal that ADAMTS13 and VWF are causally involved in myocardial I/R injury.
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PMID:ADAMTS13 deficiency exacerbates VWF-dependent acute myocardial ischemia/reperfusion injury in mice. 2325 99

Blood coagulation activation is frequently found in patients with malaria. Clinically apparent bleeding or disseminated intravascular coagulation (DIC) is associated with very severe disease and a high mortality. Protein C, protein S, and antithrombin levels were found to be low in P. falciparum, but were normal in P. vivax infection. Plasma levels of plasminogen activator inhibitor-1 were high in cases of P. falciparum infection whereas tissue plasminogen activator levels were low. Elevated plasma levels of von Willebrand factor (vWF) and vWF propeptide, thrombomodulin, endothelial microparticles have been reported in P. falciparum-infected patients. It has been demonstrated that severe P. falciparum infection is associated with acute endothelial cell (EC) activation, abnormal circulating ultralarge vWF multimers, and a significant reduction in plasma ADAMTS13 function. These changes may result in intravascular platelet aggregation, thrombocytopenia, and microvascular disease. It has also been shown that P. falciparum-parasitized red blood cells (pRBCs) induce tissue factor (TF) expression in microvascular ECs in vitro. Recently, loss of endothelial protein C receptor (EPCR) localized to sites of cytoadherent pRBCs in cerebral malaria has been demonstrated. Severe malaria is associated with parasite binding to EPCR. The cornerstone of the treatment of coagulopathy in malaria is the use of effective anti-malarial agents. DIC with spontaneous systemic bleeding should be treated with screened blood products. Study in Thailand has shown that for patients who presented with parasitemia >30% and severe systemic complications such as acute renal failure and ARDS, survival was superior in the group who received exchange transfusion. The use of heparin is generally restricted to patients with DIC and extensive deposition of fibrin, as occurs with purpura fulminans or acral ischemia. Antiplatelet agents interfere with the protective effect of platelets against malaria and should be avoided.
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PMID:Coagulopathy in malaria. 2409 98

Innate immune cells play a major role in the early response to myocardial ischemia/reperfusion (MI/R) injury. Recombinant human ADAMTS13 (rhADAMTS13), cleaving von Willebrand factor (VWF), reduces leukocyte recruitment in mice. Death of cardiomyocytes and the possible formation of neutrophil extracellular traps (NETs) may result in chromatin release that is prothrombotic and cytotoxic. We investigated the pathophysiological role of extracellular chromatin during MI/R to evaluate the therapeutic potential of targeting extracellular DNA and VWF by using DNase I with/without rhADAMTS13. Finally, we examined the impact of histone citrullination and NETosis by peptidylarginine deiminase 4 (PAD4) on MI/R. We used a 24-hour MI/R mouse surgical model. MI/R injury caused an increase in plasma nucleosomes, abundant neutrophil infiltration, and the presence of citrullinated histone H3 at the site of injury. Both monotherapies and coadministration of DNase I and rhADAMTS13 revealed a cardioprotective effect, resulting in subsequent improvement of cardiac contractile function. PAD4(-/-) mice, which do not produce NETs, were also significantly protected from MI/R and DNase I treatment had no further beneficial effect. We demonstrate that extracellular chromatin released through NETosis exacerbates MI/R injury. Targeting both VWF-mediated leukocyte recruitment and chromatin removal may be a new therapeutic strategy to reduce ischemia-related cardiac damage.
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PMID:VWF-mediated leukocyte recruitment with chromatin decondensation by PAD4 increases myocardial ischemia/reperfusion injury in mice. 2438 97

Thrombotic microangiopathies (TMAs) include several diseases, most prominently are thrombotic thrombocytopenic purpura (TTP) and hemolytic-uremic syndrome (HUS). TMAs are characterized by profound thrombocytopenia, microangiopathic hemolytic anemia and organ ischemia. In most cases TTP results from deficiency of ADAMTS13, the von Willebrand factor-cleaving protease leading to increase of ultra-large von Willebrand factor (ULVWF) multimers. Congenital TTP is due to mutations in the gene of ADAMTS13 whereas acquired TTP is due to production of autoantibodies against ADAMTS13. In both cases severe deficiency of ADAMTS13 exists. However, the presence of ADAMTS13 activity does not rule out TTP. Diagnostic criteria of TTP are based on clinical features of neurologic and renal disfunction along with anemia and thrombocytopenia, low ADAMTS13 activity, and the presence of ULVWF. The standard treatment of TTP includes plasma exchange, protein A immunoabsobtion, immunosuppressive drugs, CD20 antibodies against B cells, and splenectomy. HUS is commonly caused by infection with Shiga-toxin produced by Escherichia coli. HUS is characterized by thrombocytopenia, anemia, renal impairment and diarrhea. Rarely, atypical HUS appears as a consequence of mutations related to the alternative pathway for the compliment system. Plasmapheresis in HUS is not efficient. Alternatively, plasma therapy and in some cases dialysis are used. TMA diseases may be associated with other infections, bone marrow transplantation, pregnancy, systemic vasculitis, and certain drugs.
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PMID:Thrombotic thrombocytopenic purpura and other thrombotic microangiopathic hemolytic anemias: diagnosis and classification. 2441 4

Thrombotic microangiopathy (TMA) is a rare but serious complication of organ transplantation. This article presents the first literature review on TMA following non-renal solid organ transplantation (SOT). Ischemia-reperfusion, immunosuppressive drugs, acute interfering disease and a relative deficiency of the von Willebrand factor (vWF) cleaving protease (ADAMTS13) appear to play a major role in its pathogenesis. De novo TMA occurs in 4.0% of liver and 2.3% of lung transplant recipients, whereas the incidence remains unknown after intestinal transplantation. The median time of onset is 2, 37 and 8 weeks after liver, lung and intestinal transplantations respectively, with a three month survival of about 70%. In heart transplantation TMA is rare, occurrence is late and prognosis is poor. In TMA early after liver transplantation an elevated vWF/ADAMTS13 ratio may show diagnostic value. Early withdrawal of calcineurin inhibitors (CNI) proves to be lifesaving. Conversion to another CNI and rechallenge after resolution are generally safe, except after heart transplantation. The value of plasma exchange therapy remains controversial.
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PMID:De novo thrombotic microangiopathy after non-renal solid organ transplantation. 2526 55

Acquired thrombotic thrombocytopenic purpura (TTP) is characterized by thrombocytopenia and microangiopathic hemolytic anemia (MAHA) without an obvious cause, and may include fever, mild renal failure, and neurologic deficits. It is characterized by a deficiency of the von Willebrand factor (VWF) cleaving enzyme, ADAMTS13 (a disintegrin and metalloproteinase, with a thrombospondin type 1 motif, member 13), resulting in formation of microthrombi in the high sheer environment of the microvasculature. This causes microvascular occlusion, MAHA, and organ ischemia. Diagnosis is based on the presence of clinical symptoms, laboratory aberrations consistent with MAHA, decreased ADAMTS13 activity, and possibly presence of anti-ADAMTS13 autoantibodies. Upfront treatment of acute TTP includes plasma exchange and corticosteroids. A significant number of patients are refractory to this treatment and will require further interventions. There are limited data and consensus on the management of the refractory TTP patient. Management involves simultaneously ruling out other causes of thrombocytopenia and MAHA, while also considering other treatments. In this article, we describe our management of the patient with refractory TTP, and discuss use of rituximab, increased plasma exchange, splenectomy, and immunosuppressive options, including cyclophosphamide, vincristine, and cyclosporine. We also review recent evidence for the potential roles of bortezomib and N-acetylcysteine, and explore new therapeutic approaches, including recombinant ADAMTS13 and anti-VWF therapy.
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PMID:How I treat refractory thrombotic thrombocytopenic purpura. 2898 21

Thrombotic thrombocytopenic purpura (TTP) is a rare and potentially lethal syndrome characterized by severe thrombocytopenia, microangiopathic haemolytic anaemia, and aspecific neurologic symptoms. This syndrome is the result of an abnormal intravascular platelet aggregation which induces transient ischemia in various organs, especially in the central nervous system. Platelet aggregation causes also fragmentation of erythrocytes, thus leading to the characteristic anaemia. The exact cause of TTP is unknown, but a large body of evidence suggest that this syndrome might be due to acquired (immunological) or congenital ADAMTS13 deficiency. The dysregulation of ADAMTS 13 activity could promote massive release of high molecular weight multimers of von Willebrand factor (VWF) from endothelium and, as a consequence, could cause intravascular platelet aggregation. Pregnancy is commonly associated with numerous metabolic, immunological, and haemostatic changes which could increase thrombotic risk: during pregnancy, in fact, it is generally observed an increase of procoagulant activity and a decrease of fibrinolytic activity; moreover, at the end of pregnancy, it is not rare to find thrombocytopenia. All these reasons lead us to consider pregnancy itself as a triggering event for the onset of TTP. The authors describe a case of TTP occurred during puerperium, in a patient who underwent caesarean section.
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PMID:Post-partum management in a patient affected by thrombotic thrombocytopenic purpura: case report and review of literature. 2586 90

The understanding of molecular mechanism underlying ischemia/reperfusion-induced neuronal death and neurological dysfunction may provide therapeutic targets for ischemic stroke. In this study, miR-525-5p is clearly reduced in the ischemic brain after oxygen-glucose deprivation (OGD). Using TargetScan, MicroCosm Targets version 5, and microRNA.org databases, we identified miR-525-5p as a possible regulator of the ADAMTS13. We validated that ADAMTS13 is a target for miR-525-5p with a luciferase reporter activity assay. Moreover, adult rats subjected to focal cerebral ischemia exhibited a substantial reduction of miR-525-5p expression, which was inversely upregulated by ADAMTS13 expression. In vivo treatment with miR-525-5p agomir effectively decreased ADAMTS13 mRNA and protein levels in the ischemic region. Furthermore, knockdown of cerebral miR-525-5p reduced cell death and infarct size. In addition, the knockdown of ADAMTS13 by ADAMTS13 siRNA apparently abrogated the protective effect of miR-525-5p antagomir on OGD-induced cell death. Our data demonstrate that miR-525-5p is an endogenous regulator of ADAMTS13 that improves ischemia/reperfusion (I/R)-induced brain injury and dysfunction.
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PMID:miR-525-5p inhibits ADAMTS13 and is correlated with Ischemia/reperfusion injury-induced neuronal cell death. 2677 Apr 8


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