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Modulating the rate of fibrin formation and clot structure attenuates microvascular thrombosis in systemic inflammation.

ABSTRACT: Systemic inflammation can lead to coagulopathy and disseminated intravascular coagulation (DIC). In prior studies, the recombinant A2 domain of human von Willebrand factor (VWF; A2 protein) attenuated DIC and decreased mortality in lipopolysaccharide (LPS)-treated mice. Here, we performed studies to dissect the mechanism by which the A2 protein moderates DIC. We used confocal microscopy to analyze the fibrin clot structure in plasma from healthy humans and endotoxemic mice, turbidity assays to examine fibrin polymerization, and a murine model for LPS-induced DIC and introduced a loss-of-function mutation into the A2 protein for fibrin. The mutation of the residue E1567 located in the ?2 helix of the folded A2 domain of VWF inhibited binding activity for fibrin, possibly mapping a novel region containing a putative binding site for fibrin. The A2 protein increased the initial rate of change of fibrin polymerization, intercalated into the fibrin network, and modified the resultant clot structure in vitro. Furthermore, ex vivo experiments using plasma from mice with endotoxemia treated with the A2 protein revealed an increased rate of fibrin formation and an altered clot structure as compared with plasma from nontreated sick animals. Moreover, and in contrast to the A2 mutant, the A2 protein improved survival and reduced fibrin deposition and microvascular thrombosis in mice with endotoxemia-induced DIC. Importantly, in vivo and in vitro studies indicated that the A2 protein did not affect experimental thrombosis. Thus, we provide evidence for a novel treatment to attenuate systemic inflammation-induced coagulopathy/DIC via targeting fibrin formation, without an increased risk for bleeding.

SUBMITTER: Valladolid C

PROVIDER: S-EPMC7160269 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Modulating the rate of fibrin formation and clot structure attenuates microvascular thrombosis in systemic inflammation.

Valladolid Christian C Martinez-Vargas Marina M Sekhar Nitin N Lam Fong F Brown Cameron C Palzkill Timothy T Tischer Alexander A Auton Mathew M Vijayan K Vinod KV Rumbaut Rolando E RE Nguyen Trung C TC Cruz Miguel A MA

Blood advances 20200401 7

Systemic inflammation can lead to coagulopathy and disseminated intravascular coagulation (DIC). In prior studies, the recombinant A2 domain of human von Willebrand factor (VWF; A2 protein) attenuated DIC and decreased mortality in lipopolysaccharide (LPS)-treated mice. Here, we performed studies to dissect the mechanism by which the A2 protein moderates DIC. We used confocal microscopy to analyze the fibrin clot structure in plasma from healthy humans and endotoxemic mice, turbidity assays to e ...[more]

PMID: 32259201

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Project description:Antiphospholipid syndrome (APS) is associated with arterial and venous thrombosis. The unfavorable fibrin clot phenotype, including formation of dense and poorly lysable clots, has been reported both in thrombotic APS and venous thromboembolism (VTE). The presence and amount of different proteins within a plasma clot, not only associated with the coagulation system, may influence clot properties. To our knowledge, there is a lack of data on plasma fibrin-clot bound proteins in patients with thrombotic APS or VTE. The aim of our study was to perform a quantitative proteomic analysis of fibrin clots prepared from citrated plasma from subjects with thrombotic APS and prior VTE, along with fibrin clot permeability (Ks) and clot lysis time (CLT) assessed ex vivo. We investigated 23 consecutive patients with APS, 18 with a history of first-ever VTE, and 20 age and sex matched healthy subjects. A multiple enzyme digestion filter aided sample preparation and a multienzyme digestion (MED) FASP method combined with LC-MS/MS analysis performed on a Proxeon Easy-nLC System coupled to the Q Exactive HF mass spectrometer were used. The proteomic analysis revealed that clot composition regarding 117 proteins in APS patients and 48 proteins in VTE patients was changed as compared to healthy controls, while 72 clot-bounded proteins differed between APS and VTE subjects. In healthy controls, Ks was associated with fibrinogen alpha and gamma chains (r=0.46 and r=0.46, both p<0.05, respectively) or apolipoprotein B-100 (r=-0.53, p<0.05), while CLT correlated with annexin A2 (r=-0.58, p<0.05), apolipoportein(a) (r=0.47, p<0.05), or platelet glycoprotein 4 (r=0.59, p<0.05). In VTE patients correlations of Ks with complement C1q and histone H2B, as factors closely linked with thrombosis, were observed (r=-0.52 and r=-0.47, both p<0.05, respectively). In patients with thrombotic APS all above-mentioned associations were not found. This study is the first to show that different proteins are able to influence the clot formation, structure, and properties. Since, prothrombotic conditions abolished associations observed in healthy subjects fibrin clots, differences in protein clot components might explain the links between prothrombotic fibrin clot phenotype and thromboembolic events.

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Dataset Information

Modulating the rate of fibrin formation and clot structure attenuates microvascular thrombosis in systemic inflammation.

Publications

Modulating the rate of fibrin formation and clot structure attenuates microvascular thrombosis in systemic inflammation.

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