Ecarin Clotting Time: a Predictive Coagulation Assay for the Antithrombotic Activity of Argatroban in the Rat

1998 ◽  
Vol 79 (01) ◽  
pp. 228-233 ◽  
Author(s):  
Catherine Lunven ◽  
Christine Girardot ◽  
Irène Lechaire ◽  
Denise Girard ◽  
Marie-Christine Charles ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Arterial Thrombosis ◽  
Predictive Marker ◽  
Clotting Time ◽  
Antithrombotic Effect ◽  
Antithrombotic Activity ◽  
Thrombosis Model ◽  
Antithrombotic Effects ◽  
Ecarin Clotting Time ◽  
Predictive Assay

SummaryWe studied the use of the Ecarin Clotting Time (ECT) as a predictive assay of the antithrombotic effects of argatroban in a new tissue factor-dependent model of venous thrombosis and a model of arterial thrombosis in the rat. Heparin was used as a reference anticoagulant.Infusions of argatroban dose-dependently increased the ECT across the range of doses required for antithrombotic activity in models of venous and arterial thrombosis (1.25-40 μg/kg/min). The TT was only useful as a marker in the case of venous thrombosis, since, in the arterial thrombosis model, the clotting times were >200 s in the majority of animals receiving antithrombotic doses. The aPTT is not sufficiently sensitive to be predictive of an antithrombotic effect in the venous model, and shows only modest increases in the arterial thrombosis model. Heparin did not significantly increase the ECT at antithrombotic doses in the venous thrombosis model, and only increased the ECT by 53% at 40 μg/kg/min in the arterial model, despite a marked antithrombotic effect. Both the TT and aPTT were dose-dependently increased by heparin at doses active in the venous model, whereas both parameters were >200 s at doses active in the arterial thrombosis model.Thus, the ECT provides a predictive marker for the antithrombotic activity of argatroban in both venous and arterial thrombosis, at least in the rat.

Study of a new benzimidazole derivative having in its structure a sterically hindered phenolic substituent on models of arterial and venous thrombosis

2020 ◽  
Author(s):  
А.А. Спасов ◽  
А.Ф. Кучерявенко ◽  
К.А. Гайдукова ◽  
В.С. Сиротенко ◽  
О.Н. Жуковская
Keyword(s):  
Venous Thrombosis ◽  
Arterial Thrombosis ◽  
Benzimidazole Derivative ◽  
Vena Cava ◽  
Male Rats ◽  
Control Group ◽  
Vena Cava Inferior ◽  
Antithrombotic Activity ◽  
Thrombosis Model ◽  
Venous Thromboses

Введение: Тромбоциты являются ключевыми медиаторами патогенеза артериальных тромбозов и атеросклероза. Поэтому изучение антиагрегантных средств на предмет антитромботической активности на различных моделях артериальных и венозных тромбозов является актуальным. Цель исследования: изучение антитромботической активности соединения РУ-1144 (производного бензимидазола) в сравнении с ацетилсалициловой кислотой (АСК) и клопидогрелом на моделях артериального и венозного тромбозов. Материалы и методы: Артериальный тромбоз моделировали на сонной артерии крыс-самцов аппликацией постоянного электрического тока. Воздействие на сосуд выполняли до момента полной окклюзии, регистрируемой на мониторе доплерографа. Венозной тромбоз моделировали на крысах-самцах полной перевязкой нижней полой вены на 24 ч; через сутки проводили изъятие тромба из сосуда и его взвешивание. В экспериментальных группах животным внутрижелудочно вводили соединение РУ-1144 и препараты сравнения — АСК и клопидогрел, в контрольной группе животным внутрижелудочно вводили дистиллированную воду. Для подтверждения отсутствия влияния хирургических манипуляций на организм животного в исследование модели венозного тромбоза была включена группа ложнооперированных крыс. Результаты: На модели артериального тромбоза установлена более высокая антитромботическая активность соединения РУ-1144 по сравнению с АСК и клопидогрелом в 2,5 и 7,4 раза соответственно. В модели венозного тромбоза соединение РУ-1144 уменьшало среднюю массу венозных тромбов в 5,3 раза по сравнению с группой контроля и превосходило по антитромботической активности АСК и клопидогрел в 3,5 и 1,9 раза. Заключение: Соединение РУ-1144 способно предотвращать патологические процессы, связанные с тромбообразованием, не только в сонной артерии, но и в нижней полой вене. Background: Platelets are key mediators of the pathogenesis of arterial thrombosis and atherosclerosis. So, that is actual to study antithrombotic activity of antiplatelet agents in various models of arterial and venous thromboses. Objectives: to study the antithrombotic activity of RU-1144 compound (benzimidazole derivative) as compared with acetylsalicylic acid (ASA) and clopidogrel on models of arterial and venous thromboses. Materials/Methods: Arterial thrombosis was modeled on the carotid artery of male rats by application of direct electric current. Exposure was performed until full vessel occlusion recorded by Dopplerograf. Venous thrombosis was modeled on male rats by complete ligation of vena cava inferior for 24 hours; a day later the thrombus was removed from the vessel and weighed. In the experimental groups the animals were injected intragastrically with the compound RU-1144 and the comparison drugs — ASA and clopidogrel; in the control group the animals were administered distilled water intragastrically. To confirm the absence of the effect of surgical manipulations on the animal’s organism, a group of false-operated rats was included in the study of venous thrombosis model. Results: In arterial thrombosis model RU-1144 compound had a higher antithrombotic activity as compared with ASA and clopidogrel by 2.5 and 7.4 times, respectively. In venous thrombosis model RU-1144 compound reduced the average weight of venous clots by 5.3 times as compared with the control group and exceeded antithrombotic activity of ASA and clopidogrel by 3.5 and 1.9 times. Conclusions: RU-1144 compound capable to prevent the pathological processes associated with thrombus formation in carotid artery as well as in vena cava inferior.

The Tick Protein Ir-Cpi Efficiently Delays Contact Pathway Induced Thrombin Generation and Displays In Vivo Antithrombotic Activity

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3336-3336
Author(s):  
Severine Robert ◽  
Yves Decrem ◽  
Géraldine Rath ◽  
Chantal Dessy ◽  
Olivier Feron ◽  
...  
Keyword(s):  
Arterial Thrombosis ◽  
Thrombin Generation ◽  
Thrombus Formation ◽  
Lag Time ◽  
Antithrombotic Effect ◽  
Contact Phase ◽  
Antithrombotic Activity ◽  
Thrombosis Model ◽  
Contact Pathway

Abstract Abstract 3336 Introduction: The search for new anticoagulants is a major challenge in medicine. Contact factors have never been considered as interesting targets for the development of new anticoagulant agents since they are not required for in vivo coagulation (i.e. deficiencies affecting these factors do not cause excessive bleeding). The discovery that FXI and FXII deficiency protects against thrombosis without causing spontaneous bleeding in mice makes FXII a unique and ideal target for drug design. We demonstrated in vitro that Ir-CPI, a 67 amino acids recombinant Kunitz-type protein from Ixodes ricinus, specifically interacted with activated human contact phase factors (FXIIa, FXIa, and kallikrein). Aims: The goal of this study was to investigate the potential anticoagulant and antithrombotic efficacy of Ir-CPI. Methods: The effects of Ir-CPI were investigated on the thrombin activity during the coagulation process in human plasma using the CAT method. Three different inducers were employed to specifically trigger the coagulation pathways and to generate thrombin. A standard concentration of 5 pM TF with 4 μM PL and 16.7 mM CaCl2 was used to activate the TF pathway whereas a lower TF concentration of 1 pM with 4 μM PL and 16.7 mM CaCl2 was selected for stimulating the TF pathway in combination with the contact phase pathway through a thrombin-mediated positive feedback. The contact phase pathway was also triggered alone by ellagic acid, PL and 16.7 mM CaCl2 (25-fold diluted APTT reagent Actin FS). The effect of Ir-CPI on venous thrombus formation was assessed using a rat thrombosis model induced by complete venous stasis in the posterior vena cava and FeCl3 topical application on the outer vessel wall. Results: When stimulating plasma coagulation trough the contact pathway, Ir-CPI caused a concentration-dependent prolongation of the lag time and the Tmax and a concentration-dependent decrease in the Cmax compared to the control curve (i.e. without inhibitor). When the coagulation cascade was triggered by the TF pathway (5 or 1 pM TF), only a slight concentration-dependent decrease of the Cmax and a concentration-dependent prolongation of the lag time and the Tmax were observed. For comparison purpose, the effects of the specific competitive FXIIa inhibitor corn trypsin inhibitor (CTI) were also investigated using the three same inducers than for Ir-CPI. For the contact pathway, a concentration-dependent decrease of the Cmax and a concentration-dependent prolongation of the lag time and the Tmax were found. When stimulating the TF pathway (5 or 1 pM TF), no modification of the thrombin generation curves was observed with the tested concentrations of CTI. When comparing the results of the two inhibitors acting trough the delay of the contact pathway, we found that Ir-CPI was about 30-fold more potent than CTI. We further evaluated the antithrombotic effect of Ir-CPI on a rat venous thrombosis model induced by endothelial damage and vessel ligation, close to the physiological venous thrombus formation in humans. We showed that Ir-CPI reduced thrombosis in a dose-dependent manner with an ED50 close to 65 μg/kg. A maximum effect starting from 0.5 mg/kg was observed with a mean reduction in the clot weight/body weight of 75 ± 7%. This antithrombotic effect of Ir-CPI was exclusively mediated through the inhibition of thrombin generation since it did not interference with collagen-induced platelet aggregation. This is the first time that an inhibitor of the coagulation contact phase was shown to protect against the formation of venous thrombi. The antithrombotic effect of Ir-CPI was also confirmed using other venous and arterial thrombosis models. We also showed that the effective antithrombotic dose of Ir-CPI in these tests did not promote bleeding or impair blood coagulation parameters. Conclusions: The present study demonstrated that Ir-CPI, a recombinant protein from the tick Ixodes ricinus targeting the contact factors (FXII, FXI and kallikrein), displayed an anticoagulant activity mainly through the delay of the contact pathway induced thrombin generation. This drug also exhibited an antithrombotic activity in our venous and arterial thrombosis model. This drug may thus provide an interesting and innovative therapeutic tool for the prevention and the treatment of thromboembolic diseases with a minimal risk of therapy-associated bleeding. Disclosures: No relevant conflicts of interest to declare.

Repeated Oral or Subcutaneous LMWH Has similar Antithrombotic Activity in a Rat Venous Thrombosis Model: Antithrombotic Activity Correlates With Heparin on Endothelium When Orally Administered

2016 ◽  
Vol 22 (3) ◽  
pp. 264-272 ◽  
Author(s):  
Linda M. Hiebert
Keyword(s):  
Single Dose ◽  
Oral Administration ◽  
Venous Thrombosis ◽  
Anticoagulant Activity ◽  
Vena Cava ◽  
Antithrombotic Activity ◽  
Thrombosis Model ◽  
Normal Ranges ◽  
Long Term Treatment ◽  
Antithrombotic Effects

Low-molecular-weight heparins (LMWHs) endure as important drugs for thromboprophylaxis. Although clinical use relies on the subcutaneous (SC) route, our previous studies show that single-dose orally administered LMWHs have antithrombotic activity. Since thromboprophylaxis requires long-term treatment, we examined antithrombotic effects of subacute oral LMWHs in a rat venous thrombosis model and compared results to SC or single-dose oral administration. We measured LMWH in endothelium and plasma, weight change and complete blood counts (CBC). Oral LMWH tinzaparin (3 × 0.1 mg/kg/12 or 24 hours) or reviparin (3 × 0.025 mg/kg/24 hours) significantly decreased thrombosis compared to saline. In the subacute study (60 × 0.1 mg/kg/12 hours), oral or SC tinzaparin significantly reduced thrombosis compared to saline but not to single or 3 × 0.1 mg/kg/12 hours oral tinzaparin. Antithrombotic effects were similar between oral and SC administration. LMWH was found on endothelium following oral but not SC administration. Endothelial concentrations were significantly correlated with incidence of stable thrombi ( P = 0.021 and 0.04 for aortic and vena cava endothelium respectively, χ2 test) and total thrombi ( P = 0.003 for vena cava endothelium). Anti-Xa activity was significantly greater for oral or SC LMWH than saline and significantly greater for SC versus oral LMWH. Values for CBCs were within normal ranges (mean ± 2 SD). There was no evidence of bleeding. Weight gain was similar between groups. In conclusion, subacute oral and SC LMWH have similar antithrombotic effects. Antithrombotic activity with oral administration is correlated with endothelial LMWH concentrations but not with plasma anticoagulant activity.

Comparison of the Anticoagulant and Antithrombotic Effects of Synthetic Thrombin and Factor Xa Inhibitors

1990 ◽  
Vol 63 (02) ◽  
pp. 220-223 ◽  
Author(s):  
J Hauptmann ◽  
B Kaiser ◽  
G Nowak ◽  
J Stürzebecher ◽  
F Markwardt
Keyword(s):  
Factor Xa ◽  
Thrombin Inhibitors ◽  
Factor Xa Inhibitors ◽  
Venous Stasis ◽  
Clotting Time ◽  
Thrombosis Model ◽  
Activity Factor ◽  
Antithrombotic Effects

SummaryThe anticoagulant effect of selected synthetic inhibitors of thrombin and factor Xa was studied in vitro in commonly used clotting assays. The concentrations of the compounds doubling the clotting time in the various assays were mainly dependent on their thrombin inhibitory activity. Factor Xa inhibitors were somewhat more effective in prolonging the prothrombin time compared to the activated partial thromboplastin time, whereas the opposite was true of thrombin inhibitors.In vivo, in a venous stasis thrombosis model and a thromboplastin-induced microthrombosis model in rats the thrombin inhibitors were effective antithrombotically whereas factor Xa inhibitors of numerically similar IQ value for the respective enzyme were not effective at equimolar dosageThe results are discussed in the light of the different prelequisiles and conditions for inhibition of thrombin and factor Xa in the course of blood clotting.

Comparison of antithrombotic efficacy between edoxaban, a direct factor Xa inhibitor, and fondaparinux, an indirect factor Xa inhibitor under low and high shear rates

2011 ◽  
Vol 106 (12) ◽  
pp. 1062-1068 ◽  
Author(s):  
Naoki Tsuji ◽  
Yuko Honda ◽  
Chikako Kamisato ◽  
Yoshiyuki Morishima ◽  
Toshiro Shibano ◽  
...  
Keyword(s):  
Shear Rate ◽  
Arterial Thrombosis ◽  
Factor Xa ◽  
High Shear ◽  
Shear Rates ◽  
Thrombosis Model ◽  
Perfusion Chamber ◽  
High Shear Rates ◽  
Antithrombotic Effects ◽  
Antithrombotic Efficacy

SummaryEdoxaban is an oral, direct factor Xa (FXa) inhibitor under late-phase clinical development. This study compared the antithrombotic efficacy of edoxaban with that of an indirect FXa inhibitor, fondaparinux, in in vivo venous and arterial thrombosis models and in ex vivo perfusion chamber thrombosis model under low and high shear rates in rats. Venous and arterial thrombi were induced by platinum wire insertion into the inferior vena cava and by application of FeCl3 to the carotid artery, respectively. The perfusion chamber thrombus was formed by blood perfusion into a collagen-coated capillary at 150 s-1 (low shear rate) and 1,600 s-1 (high shear rate). Effective doses of edoxaban that reduced thrombus formation by 50% (ED50) in venous and arterial thrombosis models were 0.076 and 0.093 mg/kg/h, respectively. In contrast, ED50 of fondaparinux in the arterial thrombosis model (>10 mg/kg/h) was markedly higher compared to ED50 in the venous thrombosis model (0.021 mg/kg/h). In the perfusion chamber thrombosis model, the ratio of ED50 under high shear rate (1.13 mg/kg/h) to that under low shear rate (0.63 mg/kg/h) for edoxaban was 1.9, whereas that for fondaparinux was more than 66. While the efficacy of fondaparinux markedly decreased in arterial thrombosis and in a high-shear state, edoxaban exerted consistent antithrombotic effects regardless of flow conditions. These results suggest that shear rate is a key factor in different antithrombotic effects between edoxaban and fondaparinux.

scholarly journals Sex differences in the antithrombotic effects of aspirin

Blood ◽  
1978 ◽  
Vol 52 (5) ◽  
pp. 1073-1076 ◽  
Author(s):  
JG Kelton ◽  
J Hirsh ◽  
CJ Carter ◽  
MR Buchanan
Keyword(s):  
Clinical Trials ◽  
Animal Model ◽  
Arterial Thrombosis ◽  
Sodium Salicylate ◽  
Inhibitory Effect ◽  
Prostaglandin Synthesis ◽  
Antithrombotic Effect ◽  
Antithrombotic Agent ◽  
Male And Female ◽  
Antithrombotic Effects

Abstract Aspirin inhibits platelet function by acetylating platelet cyclooxygenase. Recent clinical trials indicate that aspirin is a promising antithrombotic agent against both venous and arterial thrombosis, but somewhat surprisingly this protective effect appears to be limited to males. To examine the potential sex-related differences in response to aspirin, we developed an animal model for quantitating fibrin accretion into an injury-induced thrombus and used it to study the effects of aspirin on thrombus size in male and female rabbits. Platelet prostaglandin synthesis was estimated by assay of platelet malondialdehyde and was significantly decreased in both male and female rabbits following treatment with 10 mg/kg aspirin (p less than 0.001). This inhibitory effect was not different for platelets from male and female rabbits. Thrombus size was significantly decreased in aspirin- treated male rabbits when compared to controls (p less than 0.05), but this aspirin effect was not apparent in female rabbits or rabbits of either sex treated with 10 mg/kg sodium salicylate. These findings support the results of clinical trials that were obtained by retrospective subgroup analysis. The reason for the sex difference is not known, but the findings raise an important issue in relationship to this mechanism of the antithrombotic effect of aspirin.

Comparative Studies of an Orally-active Factor Xa Inhibitor, YM-60828, with other Antithrombotic Agents in a Rat Model of Arterial Thrombosis

1998 ◽  
Vol 79 (02) ◽  
pp. 410-416 ◽  
Author(s):  
Kazuo Sato ◽  
Yumiko Sakai ◽  
Fukushi Hirayama ◽  
Hiroyuki Koshio ◽  
Yuta Taniuchi ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Arterial Thrombosis ◽  
Thrombus Formation ◽  
Factor Xa ◽  
Test Drug ◽  
Antithrombotic Agent ◽  
Antithrombotic Activity ◽  
Thrombosis Model ◽  
Treatment And Prevention ◽  
Orally Active

SummaryWe examined the antithrombotic activity of a novel synthetic inhibitor of factor Xa, YM-60828, in an electrically-induced carotid artery thrombosis model in rats. In the first experiment, the antithrombotic activity of YM-60828 after i.v. infusion was compared with those of heparin, darteparin and argatroban. Test drug was administered by i.v. infusion from 30 min before electrical stimulation to the end of the experiment. YM-60828 at 1 mg/kg/h significantly improved patency status, prolonged the time to occlusive thrombus formation and duration of patency. Heparin at 300 U/kg/h also improved these parameters, but were accompanied by a marked increase in systemic coagulation time. In the second experiment, the antithrombotic activity of YM-60828 after oral administration was compared with those of ticlopidine, cilostazol, aspirin, beraprost, ethyl icosapentate and warfarin. Test drug was orally administered to fasted rats 60 min before electrical stimulation. YM-60828 at 30 mg/kg p.o., but not ticlopidine, cilostazol, aspirin, beraprost, ethyl icosapentate or warfarin, significantly reduced the incidence of occlusion and improved carotid arterial patency. These results suggest that YM-60828 may be a promising antithrombotic agent for the treatment and prevention of arterial thrombosis which can be given by oral as well as intravenous administration.

EXPERIMENTAL THROMBUS FORMATION AND HAEMOSTASIS OF DIFFERENT LOW MOLECULAR WEIGHT HEPARINS AND DOSAGES

1987 ◽  
Author(s):  
R A Zimmerman ◽  
C T Rieger ◽  
K Hübner ◽  
C W Harenber ◽  
W Kübler
Keyword(s):  
Molecular Weight ◽  
Thrombus Formation ◽  
Factor Xa ◽  
Bleeding Complications ◽  
Maximum Effect ◽  
Low Molecular Weight ◽  
Antithrombotic Effect ◽  
Low Molecular Weight Heparins ◽  
Antithrombotic Activity ◽  
Thrombosis Model

Low molecular weight heparin induces a higher anti factor Xa (a-Xa) and a lower antithrombin activity in plasma in comparison to conventional heparin. From this constellation a more pronounced antithrombotic effect and a minor incidence of bleeding Complications has been suggested.Therefore the antithrombotic activity of heparins was studied in a standardized experimental thrombosis model in rabbits. Three low molecular weight heparins with a mean molecular weight of 4.200 (heparin I),4.000 (heparin II),4.600 Dalton (heparin III) and standard heparin were tested at different dosages in 120 experiments. In the first series the dose of 60 anti Xa units (a-Xa U) given initially and 60 a-Xa U/kg/h induced a reduction of the thrombus size by 40 % (heparin I),37 % (heparin II) and 53 % (heparin III) and a prolongation of the aPTT to 45 (heparin I),66 (heparin II) and 79 sec (heparin III). The a-Xa activity was minor than 0.1 U/ml. In the second series heparins were given to aim at an a-Xa activity of 0.2-0.3 U/ml. Thereby the thrombus formation could be reduced by 84 % (heparin I), 62 % (heparin II) and 39 % (heparin III). aPTT and a-Xa activity were measured at 65.5 sec and 0.22 a-Xa U/ml (heparin I),67.3 sec and 0.3 a-Xa U/ml (heparin II) and 67.5 and 0.31 a-Xa U/ml (heparin III),respectively. In the third series the increase of the a-Xa activity to more than 0.3 U/ml showed no further reduction of the thrombus formation by heparin I, while heparins II and III already at this level reachedthe antithrombotic activity of heparin I.Our data on three different low molecular weight heparins demonstrate that already a heparin level ranging at a minimal a-Xa activity induces a clear and statistically significant antithrombotic effect. A higher heparin dosage with higher a-Xa activity increases the antithrombitic effect. At a level of 0.2-0.3 a-Xa U/ml an obvious and maximum effect could be reached, but the further elevation of the a-Xa activity produced no further antithrombotic action.

THE ROLE OF A 3-0 SULFO GROUP IN THE GLUCOSAMINE RESIDUE OF A SYNTHETIC OLIGOSACCHARIDE FOR THE DETERMINATION OF ANTITHROMBOTIC ACTIONS

1987 ◽  
Author(s):  
J M Walenga ◽  
J Fareed ◽  
M Petitou ◽  
J C Lormeau ◽  
M Samama ◽  
...  
Keyword(s):  
Sulfo Group ◽  
Factor Xa ◽  
Antithrombotic Effect ◽  
Antithrombotic Activity ◽  
Thrombosis Model ◽  
Factor Xa Inhibition

We have previously reported on the antithromboticaction of a chemically synthesized heparin pentasaccharide which exhibits high affinity to anti thrombinIII and sole anti-factor Xa activity. In order to investigate the relative importance of the 3-0 sulfo group of this pentasaccharide, we evaluated the in vitro and in vivo antithrombotic activity of a synthetic pentasccharide devoid of the sulfo group at the third position of the glucosamine residue. In amidolytic and clot-based assays the 3-0 de- sulfated pentasaccharide (3-0-DP) failed to exhibit any antifactor Xa actions at concentrations <100 ug/ml in humanor rabbit plasmas, whereas pentasaccharide showed strong factor Xa inhibition at 1.0 ug/ml IK-=3.2x10 M)and at 10.0 ug/ml in rabbit plasma (K.=9.0×10™7 M). Using a rabbit stasis thrombosis model in which thrombosis was induce by human serum or an activated pro-thrombin complex concentrate, 3-0-DP failed to produce any antithrombotic action in acute intravenous regimens at dosages up to 200 ug/kg. In these two models, pentasaccharide produced >80% inhibition of induced thrombosis. These studies demonstrate the critical importance of the 3-0 sulfo group in this heparin pentasaccharide for the determination of antithrombotic activity, and that in this type of oligosaccharide, anti-factor Xa activity is responsible for producing the antithrombotic effect.

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