scholarly journals Effect of myeloperoxidase on the anticoagulant activity of low molecular weight heparin and rivaroxaban in an in vitro tumor model

2020 ◽  
Vol 18 (12) ◽  
pp. 3267-3279
Author(s):  
Minna Voigtlaender ◽  
Lennart Beckmann ◽  
Anita Schulenkorf ◽  
Bianca Sievers ◽  
Christina Rolling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Anticoagulant Activity ◽  
Tumor Model ◽  
Low Molecular Weight

Low Molecular Weight Heparin Is Responsible for the Anti-Xa Activity of Desmin 370

1996 ◽  
Vol 75 (02) ◽  
pp. 286-291 ◽  
Author(s):  
David Brieger ◽  
Joan Dawes
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Anticoagulant Activity ◽  
Factor Xa ◽  
Biologically Active ◽  
Low Molecular Weight ◽  
Dermatan Sulphate ◽  
Molecular Weight Range ◽  
Sulphated Glycosaminoglycan

SummaryDermatan sulphate does not catalyse the inactivation of factor Xa. However, the low molecular weight (LMW) dermatan sulphate Desmin 370 has been shown to generate circulating anti-Xa activity following administration to humans. Using a single batch of Desmin 370, we measured 3 U/mg of anti-Xa activity by amidolytic assay in vitro. The material responsible for this activity had a lower molecular weight range (6000 and 1800 Da) than Desmin 370 and was more highly sulphated than the bulk of the drug. Heparinase digestion of Desmin 370 eliminated 90% of the in vitro anti-Xa activity without significantly interfering with its ability to potentiate inactivation of thrombin by HCII, suggesting that the anti-Xa activity is not due to dermatan sulphate and is probably heparin. When 125I-labelled Desmin 370 together with 40 mg/kg carrier drug was administered intravenously to a rabbit, anti-Xa activity was readily detectable in the plasma for up to 10 h and had a longer half-life than the sulphated radiolabel. Most of this anticoagulant activity was recovered from the plasma by Polybrene affinity chromatography and was probably a sulphated glycosaminoglycan. Administration of the heparinase-digested drug to a rabbit resulted in 70% less anti-Xa activity than the undigested drug. We conclude that Desmin 370 contains detectable quantities of biologically active low molecular weight heparin, which is responsible for persistent anti-Xa activity following intravenous administration.

Effect of 1,6-Anhydro Bicyclic Ring Structure on the Pharmacokinetic and Pharmacodynamic Behavior of Low Molecular Weight Heparin.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1868-1868 ◽  
Author(s):  
Walter P. Jeske ◽  
Brian Neville ◽  
Qing Ma ◽  
Debra A. Hoppensteadt ◽  
Jawed Fareed
Keyword(s):  
Molecular Weight ◽  
Half Life ◽  
Low Molecular Weight Heparin ◽  
Anticoagulant Activity ◽  
Plasma Concentrations ◽  
Significant Proportion ◽  
Low Molecular Weight ◽  
Antithrombin Activity

Abstract Introduction: Heparin cleavage under alkaline conditions results in low molecular weight heparin (LMWH) chains, a significant proportion of which contain 1,6-anhydromannosamine and/or 1,6-anhydroglucosamine at the reducing end. Despite the widespread use of the LMWHs for the prophylaxis and treatment of thrombosis, it remains unclear whether such structural modifications impact the pharmacologic activity of the drug. This study examined the in vitro anticoagulant and in vivo pharmacokinetic/pharmacodynamic (PK/PD) behavior of LMWHs containing varying levels of 1,6-anhydrosugar content. Materials and Methods: By altering the temperature and pH of the depolymerization reaction, LMWHs containing 0, 5, 10, 20 and 40% 1,6-anhydrosugar were produced. These compounds were supplemented to normal human plasma and normal primate plasma and assayed for anticoagulant (APTT and Heptest) and antiprotease (anti-IIa and anti-Xa) activity. The effect of 1,6-anhydrosugar on the PK/PD profile of LMWHs was assessed by administering the 40% 1,6-anhydro LMWH or enoxaparin (~20% 1,6-anhydrosugar) intravenously to groups of non-human primates (n=4–6) at a dose of 1 mg/kg. Blood samples were collected at baseline and at various time points up to 24 hours post-administration for determination of Heptest clotting times, anti-IIa and anti-Xa activity. The biologic activities were converted to equivalent LMWH concentrations using calibration curves prepared in normal primate plasma. Results: The molecular weight profiles of these LMWHs were comparable. No effect on anticoagulant or antiprotease activity was observed when the 1,6-anhydro content varied between 0 and 10%. When the 1,6-anhydro content was increased to 20 and 40%, a content-dependent reduction in anticoagulant activity was observed such that the prolongation of the APTT and Heptest by the 40% 1,6-anhydro LMWH was 58 and 23% less, respectively, than that produced by the LMWH lacking the 1,6-anhydro group when tested in the linear range of the concentration-response curve. This effect appears to be related primarily to an interference with antithrombin activity. Inhibition of thrombin activity in an amidolytic assay was 35% lower with the 40%-anhydro LMWH compared to the 0% anhydro compound (10 mg/ml), whereas anti-Xa activity was only 7% lower. Assay dependent variations were observed in the PK/PD profiles of the 40% anhydro LMWH and enoxaparin. As expected, the half-life of antithrombin activity was considerably shorter than that of the anti-Xa activity. The pharmacokinetic behavior of the 40% 1,6-anhydro LMWH and enoxaparin in terms of half-life, area under the curve, systemic clearance and volume of distribution was not significantly different when calculated using plasma concentrations determined by anti-IIa or anti-Xa assay. When concentrations determined by Heptest were used, the AUC determined for enoxaparin was approximately 2-fold higher than that determined with the 40% anhydro LMWH. Conclusions: Microchemical changes in the structure of low molecular weight heparin oligosaccharides can induce measurable changes in the biologic activity of LMWHs. While the pharmacokinetic profile does not appear to be altered by an enhanced 1,6-anhydro content, the effect of 1,6-anhydro content on the clinical efficacy and safety of LMWHs is unknown. Such findings may have particular impact on the development of generic LMWHs.

Effects of Unfractionated and Low Molecular Weight Heparins on Platelet Thromboxane Biosynthesis “In Vivo”

1994 ◽  
Vol 72 (06) ◽  
pp. 942-946 ◽  
Author(s):  
Raffaele Landolfi ◽  
Erica De Candia ◽  
Bianca Rocca ◽  
Giovanni Ciabattoni ◽  
Armando Antinori ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Low Molecular Weight Heparin ◽  
Primary Source ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
Heparin Administration ◽  
To Receive

SummarySeveral “in vitro” and “in vivo” studies indicate that heparin administration may affect platelet function. In this study we investigated the effects of prophylactic heparin on thromboxane (Tx)A2 biosynthesis “in vivo”, as assessed by the urinary excretion of major enzymatic metabolites 11-dehydro-TxB2 and 2,3-dinor-TxB2. Twenty-four patients who were candidates for cholecystectomy because of uncomplicated lithiasis were randomly assigned to receive placebo, unfractionated heparin, low molecular weight heparin or unfractionaed heparin plus 100 mg aspirin. Measurements of daily excretion of Tx metabolites were performed before and during the treatment. In the groups assigned to placebo and to low molecular weight heparin there was no statistically significant modification of Tx metabolite excretion while patients receiving unfractionated heparin had a significant increase of both metabolites (11-dehydro-TxB2: 3844 ± 1388 vs 2092 ±777, p <0.05; 2,3-dinor-TxB2: 2737 ± 808 vs 1535 ± 771 pg/mg creatinine, p <0.05). In patients randomized to receive low-dose aspirin plus unfractionated heparin the excretion of the two metabolites was largely suppressed thus suggesting that platelets are the primary source of enhanced thromboxane biosynthesis associated with heparin administration. These data indicate that unfractionated heparin causes platelet activation “in vivo” and suggest that the use of low molecular weight heparin may avoid this complication.

Comparison of the Non-Specific Binding of Unfractionated Heparin and Low Molecular Weight Heparin (Enoxaparin) to Plasma Proteins

1993 ◽  
Vol 70 (04) ◽  
pp. 625-630 ◽  
Author(s):  
Edward Young ◽  
Benilde Cosmi ◽  
Jeffrey Weitz ◽  
Jack Hirsh
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Plasma Proteins ◽  
Low Molecular Weight Heparin ◽  
Specific Binding ◽  
Anticoagulant Activity ◽  
Factor Xa ◽  
Low Molecular Weight ◽  
Heparin Binding ◽  
Fixed Amount

SummaryThe non-specific binding of anticoagulantly-active heparin to plasma proteins may influence its anticoagulant effect. We used low affinity heparin (LAH) essentially devoid of anti-factor Xa activity to investigate the extent and possible mechanism of this non-specific binding. The addition of excess LAH to platelet-poor plasma containing a fixed amount of unfractionated heparin doubled the anti-factor Xa activity presumably because it displaces anticoagulantly-active heparin from plasma proteins. Although dextran sulfates of varying molecular weights also increased the anti-factor Xa activity, less sulfated heparin-like polysaccharides had no effect. These findings suggest that the ability to displace active heparin from plasma protein binding sites is related to charge and may be independent of molecular size. In contrast to its effect in plasma containing unfractionated heparin, there was little augmentation in anti-factor Xa activity when LAH was added to plasma containing low molecular weight heparin (LMWH), indicating that LMWH binds less to plasma proteins than unfractionated heparin. This concept is supported by studies comparing the anticoagulant activity of unfractionated heparin and LMWH in plasma with that in buffer containing antithrombin III. The anti-factor Xa activity of unfractionated heparin was 2-fold less in plasma than in the purified system. In contrast, LMWH had identical anti-factor Xa activity in both plasma and buffer, respectively. These findings may be clinically relevant because the recovered anti-factor Xa activity of unfractionated heparin was 33% lower in plasma from patients with suspected venous thrombosis than in plasma from healthy volunteers. The reduced heparin recovery in patient plasma reflects increased heparin binding to plasma proteins because the addition of LAH augmented the anti-factor Xa activity. In contrast to unfractionated heparin, there was complete recovery of LMWH added to patient plasma and little increase of anti-factor Xa activity after the addition of LAH. These findings may explain why LMWH gives a more predictable dose response than unfractionated heparin.

Neutralization of a Low Molecular Weight Heparin (LHN-1) and Conventional Heparin by Protamine Sulfate in Rats

1986 ◽  
Vol 56 (03) ◽  
pp. 318-322 ◽  
Author(s):  
V Diness ◽  
P B Østergaard
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Thrombus Formation ◽  
Experimental Models ◽  
Protamine Sulfate ◽  
Low Molecular Weight ◽  
Antithrombotic Effect ◽  
Higher Doses

SummaryThe neutralization of a low molecular weight heparin (LHN-1) and conventional heparin (CH) by protamine sulfate has been studied in vitro and in vivo. In vitro, the APTT activity of CH was completely neutralized in parallel with the anti-Xa activity. The APTT activity of LHN-1 was almost completely neutralized in a way similar to the APTT activity of CH, whereas the anti-Xa activity of LHN-1 was only partially neutralized.In vivo, CH 3 mg/kg and LHN-1 7.2 mg/kg was given intravenously in rats. The APTT and anti-Xa activities, after neutralization by protamine sulfate in vivo, were similar to the results in vitro. In CH treated rats no haemorrhagic effect in the rat tail bleeding test and no antithrombotic effect in the rat stasis model was found at a protamine sulfate to heparin ratio of about 1, which neutralized APTT and anti-Xa activities. In LHN-1 treated rats the haemorrhagic effect was neutralized when APTT was close to normal whereas higher doses of protamine sulfate were required for neutralization of the antithrombotic effect. This probably reflects the fact that in most experimental models higher doses of heparin are needed to induce bleeding than to prevent thrombus formation. Our results demonstrate that even if complete neutralization of APTT and anti-Xa activities were not seen in LHN-1 treated rats, the in vivo effects of LHN-1 could be neutralized as efficiently as those of conventional heparin. The large fall in blood pressure caused by high doses of protamine sulfate alone was prevented by the prior injection of LHN-1.

Novel concatameric heparin-binding peptides reverse heparin and low-molecular-weight heparin anticoagulant activities in patient plasma in vitro and in rats in vivo

Blood ◽  
2004 ◽  
Vol 103 (4) ◽  
pp. 1356-1363 ◽  
Author(s):  
Barbara P. Schick ◽  
David Maslow ◽  
Adrianna Moshinski ◽  
James D. San Antonio
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Tandem Repeats ◽  
Factor Xa ◽  
Low Molecular Weight ◽  
Heparin Binding ◽  
High Affinity ◽  
Binding Peptides

Abstract Patients given unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) for prophylaxis or treatment of thrombosis sometimes suffer serious bleeding. We showed previously that peptides containing 3 or more tandem repeats of heparin-binding consensus sequences have high affinity for LMWH and neutralize LMWH (enoxaparin) in vivo in rats and in vitro in citrate. We have now modified the (ARKKAAKA)n tandem repeat peptides by cyclization or by inclusion of hydrophobic tails or cysteines to promote multimerization. These peptides exhibit high-affinity binding to LMWH (dissociation constant [Kd], ≈ 50 nM), similar potencies in neutralizing anti–Factor Xa activity of UFH and enoxaparin added to normal plasma in vitro, and efficacy equivalent to or greater than protamine. Peptide (ARKKAAKA)3VLVLVLVL was most effective in all plasmas from enoxaparin-treated patients, and was 4- to 20-fold more effective than protamine. Several other peptide structures were effective in some patients' plasmas. All high-affinity peptides reversed inhibition of thrombin-induced clot formation by UFH. These peptides (1 mg/300 g rat) neutralized 1 U/mL anti–Factor Xa activity of enoxaparin in rats within 1 to 2 minutes. Direct blood pressure and heart rate measurements showed little or no hemodynamic effect. These heparin-binding peptides, singly or in combination, are potential candidates for clinical reversal of UFH and LMWH in humans.

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