inhibition of thrombin
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2021 ◽  
Vol 22 (16) ◽  
pp. 8664
Author(s):  
Agnieszka Kij ◽  
Anna Bar ◽  
Kamil Przyborowski ◽  
Bartosz Proniewski ◽  
Lukasz Mateuszuk ◽  
...  

Angiotensin II (Ang II) induces hypertension and endothelial dysfunction, but the involvement of thrombin in these responses is not clear. Here, we assessed the effects of the inhibition of thrombin activity by dabigatran on Ang II-induced hypertension and endothelial dysfunction in mice with a particular focus on NO- and 20-HETE-dependent pathways. As expected, dabigatran administration significantly delayed thrombin generation (CAT assay) in Ang II-treated hypertensive mice, and interestingly, it prevented endothelial dysfunction development, but it did not affect elevated blood pressure nor excessive aortic wall thickening. Dabigatran’s effects on endothelial function in Ang II-treated mice were evidenced by improved NO-dependent relaxation in the aorta in response to acetylcholine in vivo (MRI measurements) and increased systemic NO bioavailability (NO2− quantification) with a concomitant increased ex vivo production of endothelium-derived NO (EPR analysis). Dabigatran treatment also contributed to the reduction in the endothelial expression of pro-inflammatory vWF and ICAM-1. Interestingly, the fall in systemic NO bioavailability in Ang II-treated mice was associated with increased 20-HETE concentration in plasma (UPLC-MS/MS analysis), which was normalised by dabigatran treatment. Taking together, the inhibition of thrombin activity in Ang II-induced hypertension in mice improves the NO-dependent function of vascular endothelium and normalises the 20-HETE-depedent pathway without affecting the blood pressure and vascular remodelling.


Author(s):  
Ian Vargas ◽  
Daniel J. Stephenson ◽  
Margaret Baldwin ◽  
Joseph P. Gaut ◽  
Charles E. Chalfant ◽  
...  

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Hyodo K ◽  
◽  
Sanda T ◽  
Yoshimura M ◽  
Yamashita T ◽  
...  

Background: Atherosclerosis is characterized by a hypercoagulable state, during which coagulation and fibrinolytic factors are simultaneously activated. However, details regarding the progression of atherosclerosis remain unknown. Here, we investigated the effects of direct long-term inhibition of thrombin by dabigatran etexilate on atherosclerotic progression in apolipoprotein E–/– and low-density lipoprotein receptor–/– double-knockout mice. Methods: Mice received either standard chow (placebo group) or dabigatran-supplemented chow for 22 weeks. The amount of atherosclerosis was estimated as the ratio of the atherosclerotic area to the total aortic intimal area. Immunohistochemistry was used to examine the expression of Matrix Metalloproteinase-9 (MMP-9), Vascular Endothelial Growth Factor (VEGF), Tissue-Type Plasminogen Activator (t-PA), and Endothelial Nitric Oxide Synthase (eNOS) in atherosclerotic regions. Results: The atherosclerotic area was smaller in the dabigatran group than in the placebo group. Immunohistochemistry revealed decreased expression of MMP-9 and VEGF, but increased expression of eNOS, in the dabigatran group compared with the placebo group. t-PA expression did not differ between the groups. Conclusion: Direct long-term inhibition of thrombin by dabigatran in mice led to a decrease in atherosclerosis progression via decreased expression of MMP-9 and VEGF.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shuai Zhao ◽  
Run Tian ◽  
Jun Wu ◽  
Shaoli Liu ◽  
Yuanning Wang ◽  
...  

AbstractEffective and safe hemodialysis is essential for patients with acute kidney injury and chronic renal failures. However, the development of effective anticoagulant agents with safe antidotes for use during hemodialysis has proven challenging. Here, we describe DNA origami-based assemblies that enable the inhibition of thrombin activity and thrombus formation. Two different thrombin-binding aptamers decorated DNA origami initiates protein recognition and inhibition, exhibiting enhanced anticoagulation in human plasma, fresh whole blood and a murine model. In a dialyzer-containing extracorporeal circuit that mimicked clinical hemodialysis, the origami-based aptamer nanoarray effectively prevented thrombosis formation. Oligonucleotides containing sequences complementary to the thrombin-binding aptamers can efficiently neutralize the anticoagulant effects. The nanoarray is safe and immunologically inert in healthy mice, eliciting no detectable changes in liver and kidney functions or serum cytokine concentration. This DNA origami-based nanoagent represents a promising anticoagulant platform for the hemodialysis treatment of renal diseases.


2021 ◽  
Author(s):  
Yudai Tabuchi ◽  
Jay Yang ◽  
Masumi Taki

We created a DNA-aptamer-type covalent drug where the pharmacological effect can be reversed by the complementary strand antidote.


Marine Drugs ◽  
2020 ◽  
Vol 18 (11) ◽  
pp. 540
Author(s):  
Nadezhda E. Ustyuzhanina ◽  
Maria I. Bilan ◽  
Andrey S. Dmitrenok ◽  
Alexandra S. Silchenko ◽  
Boris B. Grebnev ◽  
...  

Fucosylated chondroitin sulfates (FCSs) PC and HH were isolated from the sea cucumbers Paracaudina chilensis and Holothuria hilla, respectively. The purification of the polysaccharides was carried out by anion-exchange chromatography on a DEAE-Sephacel column. The structural characterization of the polysaccharides was performed in terms of monosaccharide and sulfate content, as well as using a series of nondestructive NMR spectroscopic methods. Both polysaccharides were shown to contain a chondroitin core [→3)-β-d-GalNAc (N-acethyl galactosamine)-(1→4)-β-d-GlcA (glucuronic acid)-(1→]n, bearing sulfated fucosyl branches at O-3 of every GlcA residue in the chain. These fucosyl residues were different in their pattern of sulfation: PC contained Fuc2S4S and Fuc4S in a ratio of 2:1, whereas HH included Fuc2S4S, Fuc3S4S, and Fuc4S in a ratio of 1.5:1:1. Moreover, some GalNAc residues in HH were found to contain an unusual disaccharide branch Fuc4S-(1→2)-Fuc3S4S-(1→ at O-6. Sulfated GalNAc4S6S and GalNAc4S units were found in a ratio of 3:2 in PC and 2:1 in HH. Both polysaccharides demonstrated significant anticoagulant activity in a clotting time assay, which is connected with the ability of these FCSs to potentiate the inhibition of thrombin and factor Xa in the presence of anti-thrombin III (ATIII) and with the direct inhibition of thrombin in the absence of any cofactors.


2020 ◽  
Vol 117 (20) ◽  
pp. 10958-10969 ◽  
Author(s):  
Kopperuncholan Namachivayam ◽  
Krishnan MohanKumar ◽  
Darla R. Shores ◽  
Sunil K. Jain ◽  
Jennifer Fundora ◽  
...  

Necrotizing enterocolitis (NEC) is an inflammatory bowel necrosis of premature infants and an orphan disease with no specific treatment. Most patients with confirmed NEC develop moderate-severe thrombocytopenia requiring one or more platelet transfusions. Here we used our neonatal murine model of NEC-related thrombocytopenia to investigate mechanisms of platelet depletion associated with this disease [K. Namachivayam, K. MohanKumar, L. Garg, B. A. Torres, A. Maheshwari, Pediatr. Res. 81, 817–824 (2017)]. In this model, enteral administration of immunogen trinitrobenzene sulfonate (TNBS) in 10-d-old mouse pups produces an acute necrotizing ileocolitis resembling human NEC within 24 h, and these mice developed thrombocytopenia at 12 to 15 h. We hypothesized that platelet activation and depletion occur during intestinal injury following exposure to bacterial products translocated across the damaged mucosa. Surprisingly, platelet activation began in our model 3 h after TNBS administration, antedating mucosal injury or endotoxinemia. Platelet activation was triggered by thrombin, which, in turn, was activated by tissue factor released from intestinal macrophages. Compared to adults, neonatal platelets showed enhanced sensitivity to thrombin due to higher expression of several downstream signaling mediators and the deficiency of endogenous thrombin antagonists. The expression of tissue factor in intestinal macrophages was also unique to the neonate. Targeted inhibition of thrombin by a nanomedicine-based approach was protective without increasing interstitial hemorrhages in the inflamed bowel or other organs. In support of these data, we detected increased circulating tissue factor and thrombin-antithrombin complexes in patients with NEC. Our findings show that platelet activation is an important pathophysiological event and a potential therapeutic target in NEC.


2020 ◽  
Vol 4 (4) ◽  
pp. 610-618
Author(s):  
Michael Metze ◽  
Christian Pfrepper ◽  
Tristan Klöter ◽  
Stephan Stöbe ◽  
Roland Siegemund ◽  
...  

RSC Advances ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 3626-3635 ◽  
Author(s):  
Cheng-Cheng Shi ◽  
Tian-Ran Chen ◽  
Qi-Hua Zhang ◽  
Ling-Hua Wei ◽  
Chao Huang ◽  
...  

Licochalcone A, a bioactive compound from licorice, displayed strong inhibition of thrombin.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1158-1158
Author(s):  
Fakiha Siddiqui ◽  
Alfonso J Tafur ◽  
Debra Hoppensteadt ◽  
Jeanine Walenga ◽  
Walter Jeske ◽  
...  

Introduction: Andexanet Alpha (Coagulation factor Xa recombinant, inactivated Zh-zo; AA, Portola Pharmaceuticals) is a recombinant factor Xa decoy protein which is designed to reverse the effects of apixaban and rivaroxaban and is approved for the control of bleeding complications associated with their use. The molecular modification in this recombinant protein involves the substitution of serine active site by alanine and the removal of the gamma-carboxyglutamic acid (GLA) domain to restrict its assemblage into prothrombinase complex. Beside the reversal of the effects of anti-Xa agents AA is also reported to neutralize the biologic effects of heparin and related drugs. Assay dependent variations in the neutralization profile of various factor Xa inhibitors by andexanet has been recently reported https://doi.org/10.1177/1076029619847524. Since heparin and related drugs also mediate their biologic actions by inhibiting factor Xa via AT complexation, it is hypothesized that AA may also inhibit their biologic effects as measured in various laboratory assays. It is the purpose of this study is to compare the relative neutralization profile of heparin (UFH), a low molecular weight heparin, enoxaparin (E) and a chemically synthetic pentasaccharide, Fondaparinux (F) by AA. Materials and Methods: API versions of UFH, E and F were commercially obtained in powdered forms and dissolved in saline at a working dilution of 1mg/ml. AA was dissolved in saline to obtain a 10mg/ml working solution. The anticoagulant profile of UFH, E and F was studied using the activated partial thromboplastin time (APTT) and thrombin time (TT) in a concentration range of 0 - 10 ug/ml in pooled human plasma. The anti-Xa and anti-IIa studies were carried out in amidolytic assays in the same concentration range. The thrombin generation inhibition was studied using calibrated automated thrombin generation systems (CAT, Diagnostica Stago). The effect of AA on the reversal of the anticoagulant and anti-protease and thrombin generation effects of each of these agents were studied by supplementing this agent at 100 ug/ml. The results are compared to determine the difference between pre and post AA neutralization settings. Results: All agents produce a concentration dependent effect in the anticoagulant and anti-protease assays with the exception of F which showed mild anticoagulant effects, and very weak anti-IIa actions and strong anti-Xa activity. In the anti-Xa assay the IC-50 for UFH was 2.1ug/ml (0.13 um), E 4.3 ug/ml (0.95 um) and F 0.7 ug/ml (0.41 um) upon supplementation of AA the IC50s for UFH was increased to 5 ug/ml (0.31 um) and for E 5 ug/ml (1.11 um). However, there was no neutralization of the anti-Xa effects of the F by AA and the IC50 remained the same for both pre and post andexxa studies. The anticoagulant effects of UFH as measured by aPTT and TT was strongly neutralized whereas E was only partially neutralized in the aPTT assay and almost completely neutralized in the thrombin time assay. At concentrations of up to 10 ug/ml F did not produced any significant anticoagulant effects, both in the presence and absence of AA. In the thrombin generation inhibition assays, UFH produced a complete inhibition of thrombin generation which was completely reversed by AA. Although both E and F produced strong inhibition of thrombin generation, AA did not completely neutralize these effects. The results are tabulated on table 1 for the studies carried out at 10 ug/ml of UFH, E and F. Conclusion: These results indicate that AA is capable of differentially neutralizing anticoagulant and anti-protease effects of UFH in an assay dependent manner. However, AA is incapable of neutralizing the anti-Xa effects of E and F. This may be due to the relatively differential affinities of enoxaparin and fondaparinux AT complex to factor Xa rendering it inhibited in the presence of AA. These studies also demonstrate that the primary surrogate marker anti-Xa activity for measuring the activities of anti-Xa agents is not proportional to the anticoagulant and thrombin generation inhibitory effects of these agents. A global clotting assay may be a better indication of the biologic effects of these agents and their reversal by AA. Disclosures Tafur: Recovery Force: Consultancy; Janssen: Other: Educational Grants, Research Funding; BMS: Research Funding; Idorsia: Research Funding; Daichi Sanyo: Research Funding; Stago: Research Funding; Doasense: Research Funding.


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