435 research outputs found
Factor V Has Anticoagulant Activity in Plasma in the Presence of TFPI: Difference between FV1 and FV2
No full textBackground Activated factor V (FVa) is a potent procoagulant cofactor in the prothrombinase complex, whereas its precursor factor V (FV) stimulates the inhibition of factor Xa (FXa) by tissue factor pathway inhibitor-alpha (TFPI alpha), presumably by promoting TFPI alpha binding to phospholipids. Plasma FV comprises two glycosylation isoforms (FV1 and FV2) with low and high phospholipid-binding affinity, respectively. The FV1/FV2 ratio is increased in carriers of the FV R2 haplotype. Objective This article demonstrates the TFPI alpha-cofactor function of FV in plasma and compares FV1 and FV2. Materials and Methods Thrombin generation at low TF concentration was measured in FV-depleted plasma reconstituted with 0 to 100% FV, FV1 or FV2, and in 122 individuals genotyped for the R2 haplotype. The TFPI-cofactor activities of FV1 and FV2 were also investigated in a model system of TFPI alpha-mediated FXa inhibition. Results In the FV titration, thrombin generation first increased (up to 5% FV) and then progressively decreased at higher FV concentrations. This anticoagulant effect of FV, which was also observed with FV2 but not with FV1, was largely abolished by anti-TFPI alpha antibodies, suggesting that it reflects TFPI alpha-cofactor activity of FV. In the model system of TFPI alpha-mediated FXa inhibition, FV2 was a more potent TFPI alpha-cofactor than FV1, in line with their respective phospholipid affinities. Accordingly, FV R2 carriers had higher thrombin generation than non-carriers, even after correction for demographics and plasma levels of coagulation factors and inhibitors. Conclusion FV (and particularly its FV2 isoform) contributes to the TFPI alpha-dependent down-regulation of thrombin generation in plasma triggered with low TF
The role of the different Kunitz domains of TFPI in the down-regulation of the extrinsic coagulation pathway
No full textHaemophilia is a blood clotting disorder that delays clot formation and can be fatal in patients undergoing operations, accidents or injuries. It is caused by low levels of coagulation protein. Present treatment for haemophilia is to reconstitute patients with missing protein but it is an expensive treatment with a risk of developing side effects. Alternative approach is to inhibit the anticoagulants, the regulatory proteins who inhibit coagulant proteins when they are produced in excess. This thesis focuses on how to inhibit TFPI, one of the most important anticoagulant proteins. The mechanism of inhibition of coagulation proteins was studied at domain (small part of protein) level. This study contributes to the biotech or pharma companies to develop inhibitors that can help haemophilic patients to live longer with cheap medication and no side effects
Marine-derived sulfated polysaccharides enhance hemocompatibility and endothelialization of nanofibrous PCL for vascular graft applications
No full textPartial F8 gene duplication (Factor VIII Padua) associated with high factor VIII levels and familial thrombophilia
No full textHigh coagulation factor VIII (FVIII) levels are a common risk factor for venous thromboembolism (VTE), but the underlying genetic determinants are largely unknown. We investigated the molecular bases of high FVIII levels in two Italian families with severe thrombophilia. The proband of the first family had a history of recurrent VTE before the age of 50, with extremely and persistently elevated FVIII antigen and activity levels (>400%) as the only thrombophilic defect. Genetic analysis revealed a 23.4-kb tandem duplication of the proximal portion of the F8 gene (promoter, exon 1 and a large part of intron 1), which co-segregated with high FVIII levels in the family and was absent in 103 normal controls. Targeted screening of 50 unrelated VTE patients with FVIII levels ≥250% identified a second thrombophilic family with the same F8 rearrangement on the same genetic background, suggesting a founder effect. Carriers of the duplication from both families showed a ≥2-fold up-regulation of the F8 mRNA, consistent with the presence of open chromatin signatures and enhancer elements within the duplicated region. Testing of these sequences in a luciferase reporter assay pinpointed a 927-bp region of F8 intron 1 associated with >45-fold increased reporter activity in endothelial cells, potentially mediating the F8 transcriptional enhancement observed in carriers of the duplication. In conclusion, we report the first thrombophilic defect in the F8 gene (designated "FVIII Padua") associated with markedly elevated FVIII levels and severe thrombophilia in two Italian families
The role of Aldosterone and PTH in Human Primary Aldosteronism and Vascular Calcification
No full textCardiovascular diseases (CVD) represent 31% of global deaths. Considering the vast impact of CVD on healthcare systems, it is fundamentally important to investigate the most prevalent complications of CVD, such as vascular calcification. The key objective of this thesis was to gain further insight into the mechanisms by which aldosterone synthesis is regulated with an overall impact on the cardiovascular system. This was done by dissecting the molecular effectors of hyperaldosteronism in animal models. One of the conclusions was that use of phosphate binders in combination with high intake of vitamin K significantly decreases vascular calcification in CKD rats as compared to vitamin K or phosphate binders alone
Wem gehören Autor-Leser-Texte?:Das geistige Eigentum, netzliterarische Standards, die Twitteratur von @tiny_tales und das Online-Schreibprojekt <i>morgen-mehr.de</i> von Tilman Rammstedt
No full textIn the ‘Gutenberg-Galaxy’, a strong divide between the author as a creator andthe reader as a subordinated figure helped to construct and protect authors’intellectual property rights. Net literature fundamentally suspends this strongdivide, and the protection of author’s works here restricts literary productivity.The analysis of author-reader-texts as produced in the twitterature by @tiny_tales and in the online-writing-project morgen-mehr.de by Tilman Rammstedtproves the necessity to develop standards of digital literary communication andopen data
Biomolecular engineering in the design of novel therapies to treat coagulation disorders and inflammatory diseases
No full textAntisense-based RNA therapy of factor V deficiency: in vitro and ex vivo rescue of a F5 deep-intronic splicing mutation
No full textAntisense molecules are emerging as a powerful tool to correct splicing defects. Recently, we identified a homozygous deep-intronic mutation (F5 c.1296+268A>G) activating a cryptic donor splice site in a patient with severe coagulation factor V (FV) deficiency and life-threatening bleeding episodes. Here, we assessed the ability of 2 mutation-specific antisense molecules (a morpholino oligonucleotide [MO] and an engineered U7 small nuclear RNA [snRNA]) to correct this splicing defect. COS-1 and HepG2 cells transfected with a F5 minigene construct containing the patient's mutation expressed aberrant messenger RNA (mRNA) in excess of normal mRNA. Treatment with mutation-specific antisense MO (1-5 mu M) or a construct expressing antisense U7snRNA (0.25-2 mu g) dose-dependently increased the relative amount of correctly spliced mRNA by 1 to 2 orders of magnitude, whereas control MO and U7snRNA were ineffective. Patient-derived megakaryocytes obtained by differentiation of circulating progenitor cells did not express FV, but became positive for FV at immunofluorescence staining after administration of antisense MO or U7snRNA. However, treatment adversely affected cell viability, mainly because of the transfection reagents used to deliver the antisense molecules. Our data provide in vitro and ex vivo proof of principle for the efficacy of RNA therapy in severe FV deficiency, but additional cytotoxicity studies are warranted
- …
