scholarly journals Antiplatelet drugs and generation of thrombin in clotting blood

Blood ◽  
1992 ◽  
Vol 80 (8) ◽  
pp. 2006-2011 ◽  
Author(s):  
A Szczeklik ◽  
M Krzanowski ◽  
P Gora ◽  
J Radwan
Keyword(s):  
Oral Administration ◽  
Thrombin Generation ◽  
Ex Vivo ◽  
Coagulation Factors ◽  
Antiplatelet Drugs ◽  
Specific Marker ◽  
Rate Of Increase ◽  
Synthase Inhibitor ◽  
Thrombin Formation

Platelets participate in formation of thrombin through secretion of coagulation factors and by providing a catalytic surface on which prothrombinase complex is assembled. We studied the effects of four antiplatelet drugs on thrombin formation in healthy volunteers. Thrombin generation was monitored both in vitro--in recalcified plasma-- and ex vivo--in blood emerging from a standardized skin microvasculature injury, which also served to determine bleeding time. A mathematical model has been developed to describe the latter reaction. It is based on estimation of the rate of increase in fibrinopeptide A (FPA), a specific marker of thrombin activity, in blood emerging from skin incisions. Two hours after the ingestion of 500 mg of aspirin, thrombin formation became significantly impaired both in vitro and ex vivo. In contrast, 2 hours after the oral administration of placebo, indomethacin 50 mg, or OKY-046 (a thromboxane synthase inhibitor) 400 mg, thrombinogenesis remained unaltered. Ticlopidine, studied either 3 hours after 500 mg oral administration, or after 5 days of intake at a daily dose of 500 mg, had no effect on thrombin generation. Thus, aspirin, contrary to other antiplatelet drugs, depresses thrombin formation in clotting blood, a phenomenon that might be of clinical relevance. It is suggested that aspirin exerts this effect by acetylating prothrombin and/or macromolecules of platelet membrane.

scholarly journals Antiplatelet drugs and generation of thrombin in clotting blood

Blood ◽  
1992 ◽  
Vol 80 (8) ◽  
pp. 2006-2011 ◽  
Author(s):  
A Szczeklik ◽  
M Krzanowski ◽  
P Gora ◽  
J Radwan
Keyword(s):  
Oral Administration ◽  
Thrombin Generation ◽  
Ex Vivo ◽  
Coagulation Factors ◽  
Antiplatelet Drugs ◽  
Specific Marker ◽  
Rate Of Increase ◽  
Synthase Inhibitor ◽  
Thrombin Formation

Abstract Platelets participate in formation of thrombin through secretion of coagulation factors and by providing a catalytic surface on which prothrombinase complex is assembled. We studied the effects of four antiplatelet drugs on thrombin formation in healthy volunteers. Thrombin generation was monitored both in vitro--in recalcified plasma-- and ex vivo--in blood emerging from a standardized skin microvasculature injury, which also served to determine bleeding time. A mathematical model has been developed to describe the latter reaction. It is based on estimation of the rate of increase in fibrinopeptide A (FPA), a specific marker of thrombin activity, in blood emerging from skin incisions. Two hours after the ingestion of 500 mg of aspirin, thrombin formation became significantly impaired both in vitro and ex vivo. In contrast, 2 hours after the oral administration of placebo, indomethacin 50 mg, or OKY-046 (a thromboxane synthase inhibitor) 400 mg, thrombinogenesis remained unaltered. Ticlopidine, studied either 3 hours after 500 mg oral administration, or after 5 days of intake at a daily dose of 500 mg, had no effect on thrombin generation. Thus, aspirin, contrary to other antiplatelet drugs, depresses thrombin formation in clotting blood, a phenomenon that might be of clinical relevance. It is suggested that aspirin exerts this effect by acetylating prothrombin and/or macromolecules of platelet membrane.

scholarly journals Sulfated agaran with 4,6-pyruvated form from red seaweed Acanthophora muscoides attenuates thrombin formation: in vitro and ex vivo studies

2021 ◽  
Vol 43 ◽  
pp. e55043
Author(s):  
José Ariévilo Gurgel Rodrigues ◽  
Johnny Peter Macedo Feitosa ◽  
Sandra de Aguiar Soares ◽  
Norma Maria Barros Benevides
Keyword(s):  
Thrombin Generation ◽  
Ex Vivo ◽  
Polyacrylamide Gel Electrophoresis ◽  
Deae Cellulose ◽  
Continuous Model ◽  
Sulfated Polysaccharides ◽  
Extrinsic Pathway ◽  
Plasma Fraction ◽  
Thrombin Formation

In vitro studies have described the sulfated agaran from Acanthophora muscoides as an intrinsic inhibitor of thrombin generation (TG), but not in ex vivo assay. This investigation partially characterized a pyruvate fraction with in vitro and ex vivo effects on an intrinsic/extrinsic pathway-induced thrombin generation (TG) continuous model using 36 or 60-fold diluted mice or defibrinated, normal human plasma. Fraction separated by DEAE-cellulose chromatography exhibited charge homogeneity and non-sulfated polysaccharides (<100 kDa) by agarose and polyacrylamide gel electrophoresis, respectively, using Stains-all alone. Fourier Transform Infrared and Nuclear Magnetic Resonance studies indicated a 4,6-pyruvated agaran-structure. The fraction and heparin had no effect on prothrombin time, but there was a preponderant intrinsic rather than extrinsic pathway inhibition in TG assay; themselves, acting on both free and fibrin bound thrombin activity without chromogenic substrate interaction. Both fractions, desulfated and native, anticipated and induced thrombin formation in activators-devoid or normal plasma. In addition, mice pretreated with fraction (20 mg kg-1, intraperitoneally) reduced intrinsically plasma TG ex vivo after 2h. Heparin suppressed TG in vitro, but induced it ex vivo. Therefore, agaran from A. muscoides blocks TG on in vitro and ex vivo studies, suggesting to evaluate the blood coagulability status.

Thrombin Generation Measured Ex Vivo Following Microvasculor Injury Is Increased in SLE Patients with Antiphospholipid-protein Antibodies

1997 ◽  
Vol 78 (04) ◽  
pp. 1173-1177 ◽  
Author(s):  
Jacek Musiał ◽  
Jakub Swadźba ◽  
Miłosz Jankowski ◽  
Marek Grzywacz ◽  
Stanisława Bazan-Socha ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Thrombin Generation ◽  
Ex Vivo ◽  
Skin Incision ◽  
Anticardiolipin Antibodies ◽  
Small Blood Vessel ◽  
Anionic Phospholipids ◽  
Increased Risk ◽  
High Concentrations

SummaryAntiphospholipid-protein antibodies (APA) include lupus-type anticoagulant (LA) and antibodies recognizing complexes of anionic phospholipids (e.g. cardiolipin) and proteins (e.g. prothrombin and (β2-glycoprotein I). The presence of APA is associated with an increased risk of both arterial and venous thrombosis. However, the pathogenic mechanism leading to thrombosis in patients with APA remains unclear. We studied 32 patients with systemic lupus erythematosus (SLE) who were divided into two groups depending on the presence (n = 19) or absence (n = 13) of APA. Healthy volunteers (n = 12) matched by age and sex served as controls. In all subjects LA and IgG class anticardiolipin antibodies (ACA) were determined. Thrombin generation was monitored ex vivo measuring fibrinopeptide A (FPA) and prothrombin fragment F1 + 2 (F1 + 2) in blood emerging from a skin microvasculature injury, collected at 30 second intervals. In subjects with antiphospholipid antibodies mean FPA and F1 + 2 concentrations were signiF1cantly higher at most blood sampling times than in controls. In some SLE patients with APA the process of thrombin generation was clearly disturbed and very high concentrations of F1brinopeptide A were detected already in the F1rst samples collected. Two minutes after skin incision SLE patients without APA produced slightly more FPA, but not F1 + 2, as compared to healthy subjects. Mathematical model applied to analyze the thrombin generation kinetics revealed that APA patients generated signiF1cantly greater amounts of thrombin than healthy controls (p = 0.02 for either marker). In contrast, in the same patients generation of thrombin in recalciF1ed plasma in vitro was delayed pointing to the role of endothelium in the phenomenon studied. In summary, these data show for the F1rst time that in SLE patients with antiphospholipid-protein antibodies thrombin generation after small blood vessel injury is markedly increased. Enhanced thrombin generation might explain thrombotic tendency observed in these patients.

Biochemical and Pharmacological Properties of SANORG 34006, a Potent and Long-Acting Synthetic Pentasaccharide

Blood ◽  
1998 ◽  
Vol 91 (11) ◽  
pp. 4197-4205 ◽  
Author(s):  
J.M. Herbert ◽  
J.P. Hérault ◽  
A. Bernat ◽  
R.G.M. van Amsterdam ◽  
J.C. Lormeau ◽  
...  
Keyword(s):  
Thrombin Generation ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Factor Xa ◽  
Therapeutic Index ◽  
Inhibitory Effect ◽  
Experimental Models ◽  
Treatment And Prevention ◽  
Long Acting

Abstract SANORG 34006 is a new sulfated pentasaccharide obtained by chemical synthesis. It is an analog of the “synthetic pentasaccharide” (SR 90107/ ORG 31540) which represents the antithrombin (AT) binding site of heparin. SANORG 34006 showed a higher affinity to human AT than SR 90107/ORG 31540 (kd = 1.4 ± 0.3 v 48 ± 11 nmol/L), and it is a potent and selective catalyst of the inhibitory effect of AT on factor Xa (1,240 ± 15 anti–factor Xa U/mg v850 ± 27 anti-factor Xa U/mg for SR 90107/ORG 31540). In vitro, SANORG 34006 inhibited thrombin generation occurring via both the extrinsic and intrinsic pathway. After intravenous (IV) or subcutaneous (SC) administration to rabbits, SANORG 34006 displayed a long-lasting anti–factor Xa activity and inhibition of thrombin generation (TG) ex vivo. SANORG 34006 was slowly eliminated after IV or SC administration to rats, rabbits, and baboons, showed exceptionally long half-lives (between 9.2 hours in rats and 61.9 hours in baboons), and revealed an SC bioavailability near 100%. SANORG 34006 displayed antithrombotic activity by virtue of its potentiation of the anti–factor Xa activity of AT. It strongly inhibited thrombus formation in experimental models of thromboplastin/stasis-induced venous thrombosis in rats (IV) and rabbits (SC) (ED50values = 40.0 ± 3.4 and 105.0 ± 9.4 nmol/kg, respectively). The duration of its antithrombotic effects closely paralleled the ex vivo anti–factor Xa activity. SANORG 34006 enhanced rt-PA–induced thrombolysis and inhibited accretion of125I-fibrinogen onto a preformed thrombus in the rabbit jugular vein suggesting that concomitant use of SANORG 34006 during rt-PA therapy might be helpful in facilitating thrombolysis and preventing fibrin accretion onto the thrombus under lysis. Contrary to standard heparin, SANORG 34006 did not enhance bleeding in a rabbit ear incision model at a dose that equals 10 times the antithrombotic ED50 in this species and, therefore, exhibited a favorable therapeutic index. We suggest that SANORG 34006 is a promising compound in the treatment and prevention of various thrombotic diseases.

scholarly journals Assessment of Effects of Laser Light Combining Three Wavelengths (450, 520 and 640 nm) on Temperature Increase and Depth of Tissue Lesions in an Ex Vivo Study

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5340
Author(s):  
Kamil Jurczyszyn ◽  
Witold Trzeciakowski ◽  
Zdzisław Woźniak ◽  
Piotr Ziółkowski ◽  
Mateusz Trafalski
Keyword(s):  
Duty Cycle ◽  
Temperature Increase ◽  
Ex Vivo ◽  
Visible Spectrum ◽  
Maximum Temperature ◽  
Lesion Depth ◽  
Single Beam ◽  
Duty Cycles ◽  
Rate Of Increase

Background: Lasers are widely used in medicine in soft and hard tissue surgeries and biostimulation. Studies found in literature typically compare the effects of single-wavelength lasers on tissues or cell cultures. In our study, we used a diode laser capable of emitting three components of visible light (640 nm, red; 520 nm, green; 450 nm, blue) and combining them in a single beam. The aim of the study was to assess the effects of laser radiation in the visible spectrum on tissue in vitro, depending on the wavelength and pulse width. Methods: All irradiations were performed using the same output power (1.5 W). We used various duty cycles: 10, 50, 80 and 100% with 100 Hz frequency. Maximum superficial temperature, rate of temperature increase and lesion depth were investigated. Results: Maximum superficial temperature was observed for 450 + 520 nm irradiation (100% duty cycle). The highest rate of increase of temperature was noted for 450 + 520 nm (100% duty cycle). Maximum lesion depth was observed in case of three-wavelength irradiation (450 + 520 + 640 nm) for 100, 80 and 50% duty cycles. Conclusions: The synergistic effect of two-wavelength (450 + 520 nm) irradiation was observed in case of maximum temperature measurement. The deepest depth of lesion was noted after three-wavelength irradiation (450 + 520 + 640 nm).

scholarly journals Neuroinflammation in Aged Brain: Impact of the Oral Administration of Ellagic Acid Microdispersion

2020 ◽  
Vol 21 (10) ◽  
pp. 3631 ◽  
Author(s):  
Raffaella Boggia ◽  
Federica Turrini ◽  
Alessandra Roggeri ◽  
Guendalina Olivero ◽  
Francesca Cisani ◽  
...  
Keyword(s):  
Oral Administration ◽  
Ellagic Acid ◽  
Ex Vivo ◽  
Behavioral Skills ◽  
Aged Mice ◽  
Age Related ◽  
The Central Nervous System ◽  
The Impact ◽  
Old Mice

The immune system and the central nervous system message each other to preserving central homeostasis. Both systems undergo changes during aging that determine central age-related defects. Ellagic acid (EA) is a natural product which is beneficial in both peripheral and central diseases, including aging. We analyzed the impact of the oral administration of a new oral ellagic acid micro-dispersion (EAm), that largely increased the EA solubility, in young and old mice. Oral EAm did not modify animal weight and behavioral skills in young and old mice, but significantly recovered changes in “ex-vivo, in vitro” parameters in old animals. Cortical noradrenaline exocytosis decreased in aged mice. EAm administration did not modify noradrenaline overflow in young animals, but recovered it in old mice. Furthermore, GFAP staining was increased in the cortex of aged mice, while IBA-1 and CD45 immunopositivities were unchanged when compared to young ones. EAm treatment significantly reduced CD45 signal in both young and old cortical lysates; it diminished GFAP immunopositivity in young mice, but failed to affect IBA-1 expression in both young and old animals. Finally, EAm treatment significantly reduced IL1beta expression in old mice. These results suggest that EAm is beneficial to aging and represents a nutraceutical ingredient for elders.

Impaired Haemostasis by Intravenous Administration of a Gelatin-based Plasma Expander in Human Subjects

1998 ◽  
Vol 79 (02) ◽  
pp. 286-290 ◽  
Author(s):  
M. Levi ◽  
F. Berends ◽  
A. E. van der Ende ◽  
J. W. ten Cate ◽  
C. P. Stoutenbeek ◽  
...  
Keyword(s):  
Thrombin Generation ◽  
Human Subjects ◽  
Fold Increase ◽  
Coagulation Factors ◽  
Platelet Glycoprotein ◽  
Plasma Expander ◽  
Plasma Substitute ◽  
Significant Impairment ◽  
Randomised Controlled

SummaryThe aim of this study was to investigate the effects of a gelatin-based plasma expander on blood coagulation and haemostasis in human subjects.Six healthy men were studied in a randomised, controlled cross-over study to investigate the effects of a 60 min intravenous infusion of either 1 l gelatin-based plasma substitute (Gelofusine) or 0.9% NaCl (control). The infusion of gelatin resulted in a 1.7 fold increase in bleeding time at 60 min and a 1.4 fold increase at 120 min, while saline had no effect (p <0.05). Aggregation studies revealed a significant impairment of ristocetin-induced platelet aggregation (p <0.05), associated with a substantial decrease of vWF:ag (–32% vs. –5%, p <0.05) and ristocetin co-factor (–29% vs. +1%, p <0.05) and without in vitro impairment of the platelet glycoprotein 1b receptor. Gelatin caused a decrease in thrombin-antithrombin complexes (–45% vs. –4%, p <0.05) and F1+2 (–40% vs. +1%, p <0.05). The decrease in circulating levels of vWF:ag, vWF R:Co, thrombin-antithrombin complexes and F1+ 2 was more than could be expected by the calculated plasma-dilution generated by Gelofusine.Our results demonstrated that the administration of a gelatin-based plasma substitute results in a significant impairment of primary haemostasis and thrombin generation. The defect in primary haemostasis appears to be related to a gelatin-induced reduction in von Willebrand factor, whereas the decreased thrombin generation may be due to the dilution of coagulation factors induced by Gelofusine.

A Novel Congenital Bleeding Disorder Related to High Plasma Heparin-Like Anticoagulant Activity.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4074-4074
Author(s):  
Zhaoyue Wang ◽  
Haiyen Yang ◽  
Xia Bai ◽  
Wei Zhang ◽  
Changgeng Ruan
Keyword(s):  
Ex Vivo ◽  
Anticoagulant Activity ◽  
Coagulation Factors ◽  
High Plasma ◽  
Bleeding Disorder ◽  
Normal Plasma ◽  
Normal Ranges ◽  
Coagulation Tests ◽  
Plasma Heparin

Abstract Heparin or heparin-like compounds present in human plasma in minute amounts. It has been reported that a very few patients with such diseases as plasma cell neoplasms, acute monoblastic leukemia and acquired immune deficincy syndrome have an increased plasma heparin-like anticoagulant activity. Recently, we found a 10-year-old girl who was physically and developmentally normal, but had recurrent episodes of prolonged bleeding and hematoma starting in her early childhood, which could be stopped by transfusion of fresh frozen plasma or prothrombin complex concentrate. The coagulation tests of her plasma were regularly repeated since she was 2 years old, and always revealed a markedly prolonged APTT (61.8–104 seconds, normal 28–40 seconds) and TT (36–50.1 seconds, normal 14–21 seconds), and a slightly prolonged PT (15.9–25 seconds, normal 11–14.5 seconds). Fibrinogen, prothrombin and other coagulation factors as well as anticoagulant and fibrinolytic systems were all normal. The results of immunologic measurements were either negative or within normal ranges. Treatment of the patient’s plasma in vitro with either protamine or heparinase could completely normalize the coagulation abnormalities, but not with normal plasma. The anticoagulant activity of her plasma corresponded to 0.2 heparin U/mL when measured by a TT assay using normal plasma as substrate and standardized with porcine heparin. Her plasma heparin concentration was 0.22 heparin U/mL when measured using a colometric assay. In ex vivo study, the abnormal coagulation tests could effectively be corrected when the patient was intravenously administed with protamine. Considering these characteristic laboratory features of the patient, we suppose it would probably represent a novel congenital bleeding disorder related to high plasma heparin-like anticoagulant activity which, to our knowledge, had not been described before.

Trace FVIII Augments Rfviia Induced Thrombin Generation and Improves Hemostasis in Hemophilia A Patients with Inhibitors: A clinical Cohort Study

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 40-40
Author(s):  
Tami Livnat ◽  
Uri Martinowitz ◽  
Shirley Azar-Avivi ◽  
Ariela Zivelin ◽  
Gili Kenet
Keyword(s):  
Thrombin Generation ◽  
Hemophilia A ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Therapy Response ◽  
Response To Therapy ◽  
Individual Therapy ◽  
Severe Bleeding ◽  
Inhibitor Level

Abstract Abstract 40 Treatment of Hemophilia A patients with inhibitors is challenging, as correlation between inhibitor level and hemostatic response to therapy may be limited. Thrombin generation (TG) assays may be used to monitor hemostasis and/or predict patients' response to various bypass agents. Since combination of excess FVIII and bypassing agents may potentiate improved TG in inhibitor plasma tested in-vitro, we aimed to define the therapeutic feasibility of co-administration of rFVIIa and FVIII in hemophilia A patients with inhibitors. Patients and Methods: Following consent, blood was sampled from 15 hemophilia patients (age: 0.5–46y) with inhibitor (0.5–668 BU). Platelet poor plasma (PPP) was prepared, spiked and incubated with excess FVIII. Ex-vivo kinetics of FVIII neutralization over time was evaluated by sequential measurements of residual FVIII activity. We then used recalcification induced-TG (performed in PPP supplemented with 4μM phospholipids), to measure the ex-vivo response to increasing concentrations of FVIII (0–200%) and rFVIIa (0–6.8μg/ml), alone or in combination. Based upon these ex-vivo studies, an individually tailored therapeutic regimen of concomitant bolus doses of rFVIIa and FVIII was applied to nine hemophilia patients with inhibitors. Results: FVIII ex- vivo measurements post incubation detected either rapid or slow neutralization- not correlating with inhibitor level. Flat baseline TG curves were recorded for all inhibitor patients, with variable responses to FVIII and/or rFVIIa. Combined spiking with FVIII and rFVIIa dramatically increased rFVIIa induced ETP (762.7 ±305.7 as compared to 339.3±179.9 nM/min with rFVIIa only) and peak height (48.7±23.6 vs 23.7±16.6) in all patients' plasma samples. Based upon individual ex vivo assays, concomitant bolus doses of rFVIIa (120–200 mcg/kg) and FVIII (50–100 U/Kg), were applied to 9 patients, for a total of 333 episodes during study period (February 2010-Septemeber 2012). Patients during immune tolerance received rFVIIa prophylaxis with combined rFVIIa/FVIII dosing applied 3 times weekly. For most mild- moderate joint bleeds hemostasis was defined as satisfactory following a single combined dose. Severe bleeding episodes or target joint bleeds responded to 2–8 (median:3) combined doses, applied every 12 hours. During study period the median number of spontaneous joint bleeds decreased from 4 to 1 per month. Neither thrombosis nor any other complications evolved. Conclusions: Prediction of individual therapy response may be achieved by pre-analytical studies, assessing FVIII neutralization kinetics as well as ex-vivo TG responses to combined bypass/FVIII therapy. Such studies enabled treatment of inhibitor patients according to individually tailored regimens. We confirmed for the first time that the in- vitro advantage of combining FVIII and rFVIIa, indeed accounts for improved hemostasis and may safely be applied to inhibitor patients. Disclosures: No relevant conflicts of interest to declare.

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