PLATELET ADHESION AND THROMBIN DEPENDENT AGGREGATION OF PATIENTS WITH AN UREMIC BLEEDING TENDENCY

1987 ◽  
Author(s):  
Jaap J Zwaginga ◽  
Philip G de Groot ◽  
Jan J Sixma
Keyword(s):  
Molecular Weight ◽  
Whole Blood ◽  
Low Molecular Weight Heparin ◽  
Platelet Adhesion ◽  
Umbilical Artery ◽  
Bleeding Time ◽  
Low Molecular Weight ◽  
Bleeding Tendency ◽  
Perfusion Chamber ◽  
Normal Plasma

Five patients with chronic renal insufficiency (CRI) presented a Simplate bleeding time of > 30’, two patients had normal bleeding times (< 9’)- Blood was collected before standard hemodialysis into 19 mM citrate (plasma concentration). It was circulated fojr 5’ through an annular perfusion chamber at a shear of 1300 s™1 over inverted umbilical artery segments. CRI blood’s hematocrit was raised to .3 by adding their own RBC’s. Control whole blood perfusates with Ht .3 were made by addition of their own plasma. After perfusion platelet adhesion on the artery was evaluated by microscope, corrected for platelet count of the perfusate and given as percentage surface covered. Control donors showed a 37.4 ± 5.2% coverage not different from ‘bleeding’ patients 38.0 ± 4.5% ’non bleeding’ CRI patients: 32.3 ± 3.9. We also perfused blood of three ’bleeding’ CRI patients in a new thrombus forming system. In a rectangular perfusion chamber (J Lab Clin Med 1983, 522-532) blood anticoagulated with low molecular weight heparin (Fragmin1, Kabi Vitrum) was circulated over tissue factor containing matrix of 43-phorbol 12-myristate 13-acetate perturbed endothelial cells. Locally formed thrombin stimulated platelet aggregation on this matrix. Aggregation was expressed as percentage of spread platelets covered with aggregates. Perfusions with the following perfusates were performed: whole blood of controls (WBc) and patients (WBp), CRI platelets with normal plasma and RBC’s (A), CRI plasma with normal platelets and RBC’s (B) and normal platelets with normal plasma and RBC’s (C).Platelet adhesion of CRI whole blood is not defective, aggregation, however, is. Uremic platelets in normal plasma may have an adhesion defect (A). The defective aggregation caused by uremic plasma (B) seems to be corrected for uremic platelets in normal plasma (A).

scholarly journals Adhesion of platelets to human artery subendothelium: effect of factor VIII-von Willebrand factor of various multimeric composition

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 128-139 ◽  
Author(s):  
JJ Sixma ◽  
KS Sakariassen ◽  
NH Beeser-Visser ◽  
M Ottenhof-Rovers ◽  
PA Bolhuis
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Bleeding Time ◽  
Low Molecular Weight ◽  
Perfusion Chamber ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Adhesion Factor

Abstract The relationship between the multimeric size of factor VIII-von Willebrand factor (FVIII-vWF) and the support of platelet adhesion to subendothelium was studied in an annular perfusion chamber, employing human renal and umbilical arteries. Commercial factor VIII concentrates containing multimers of low molecular weight that had been shown not to correct the bleeding time upon infusion into patients with von Willebrand's disease did not support platelet adhesion in the perfusion chamber. Cryoprecipitate and two experimental FVIII-vWF concentrates containing multimers of high molecular weight supported platelet adhesion. Factor VIII-vWF purified from cryoprecipitate was subdivided into three fractions of different molecular weights (6.0–14.0, 4.0–9.0, and 3.0–7.5 X 10(6) dalton). These fractions appeared to bind equally well and to be equally effective in supporting platelet adhesion. Factor VIII-vWF with multimers of low molecular weight (0.5–1.5 X 10(6) dalton) were prepared by partial reduction. Binding of FVIII-vWF to subendothelium was not impaired, and the support of platelet adhesion appeared to be more resistant to the effect of reduction than the ristocetin cofactor activity. At high shear rate (2,500 sec-1), increased platelet adhesion was observed with partially reduced FVIII- vWF. These data indicate that the ability of FVIII-vWF preparations to correct the bleeding time is reflected in enhanced platelet adhesion to subendothelium in a perfusion chamber. These data also emphasize that multimeric size is not the only factor determining whether FVIII-vWF will support platelet adhesion.

scholarly journals Adhesion of platelets to human artery subendothelium: effect of factor VIII-von Willebrand factor of various multimeric composition

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 128-139
Author(s):  
JJ Sixma ◽  
KS Sakariassen ◽  
NH Beeser-Visser ◽  
M Ottenhof-Rovers ◽  
PA Bolhuis
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Bleeding Time ◽  
Low Molecular Weight ◽  
Perfusion Chamber ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Adhesion Factor

The relationship between the multimeric size of factor VIII-von Willebrand factor (FVIII-vWF) and the support of platelet adhesion to subendothelium was studied in an annular perfusion chamber, employing human renal and umbilical arteries. Commercial factor VIII concentrates containing multimers of low molecular weight that had been shown not to correct the bleeding time upon infusion into patients with von Willebrand's disease did not support platelet adhesion in the perfusion chamber. Cryoprecipitate and two experimental FVIII-vWF concentrates containing multimers of high molecular weight supported platelet adhesion. Factor VIII-vWF purified from cryoprecipitate was subdivided into three fractions of different molecular weights (6.0–14.0, 4.0–9.0, and 3.0–7.5 X 10(6) dalton). These fractions appeared to bind equally well and to be equally effective in supporting platelet adhesion. Factor VIII-vWF with multimers of low molecular weight (0.5–1.5 X 10(6) dalton) were prepared by partial reduction. Binding of FVIII-vWF to subendothelium was not impaired, and the support of platelet adhesion appeared to be more resistant to the effect of reduction than the ristocetin cofactor activity. At high shear rate (2,500 sec-1), increased platelet adhesion was observed with partially reduced FVIII- vWF. These data indicate that the ability of FVIII-vWF preparations to correct the bleeding time is reflected in enhanced platelet adhesion to subendothelium in a perfusion chamber. These data also emphasize that multimeric size is not the only factor determining whether FVIII-vWF will support platelet adhesion.

NEUTRALIZING EFFECT OF PLATELET FACTOR 4 OR HISTIGINE-RICH GLYCOPROTEIN AGAINST LOW MOLECULAR WEIGHT HEPARIN AND UNFRACTIONATED HEPARIN

1987 ◽  
Author(s):  
K Takahashi ◽  
M Niwa ◽  
N Sakuragawa
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Antithrombin Iii ◽  
Platelet Factor 4 ◽  
Low Molecular Weight ◽  
Bleeding Tendency ◽  
Human Origin ◽  
Platelet Factor ◽  
At Iii ◽  
Antifactor Xa

Purpose: Low molecular weight(LMW) heparin shows stronger antifactor Xa(F-Xa) and weaker anti-thrombin(TH) activities compared with unfractionated(UF) heparin, and shows less bleeding tendency in the cases of clinical use. Platelet factor 4(Pf-4) and histidine-rich glycoprotein(HRG) neutralize heparin. We investigated on the heparin neutralizing effects of them to both kinds of heparinMaterials and methods: LMW heparin(Kabi and Pharmuka) and UF heparin(Novo) were used. Antithrombin III(AT-III), HRG(human origin ) and pf-4( bovine origin ) were purified by our methodsTH(Green-Cross) and F-Xa(Sigma) were used. Reaction mixtures for anti-TH or anti-F-Xa were as follows: 1 vol of AT-III( 0.1 U/ml)+ 1 vol of heparin( 10 ug/ml)+l vol of pf-4 or HRG(varied)→incubated for 5 min→+l vol of TH(5 U/ml) or F-Xa( 7 nKat/ml)→incubated for 5 min→ + S-2238 or S-2222→ recorded at 405 nm.Results: (1) Pf-4 showed the equivalent anti-TH effect on both kinds of heparin, and 3 ug of pf-4 neutralized 1 ug of heparinOn F-Xa neutralizing effect, 13 ug of pf-4 neutralized 1 ug of UF heparin, but could not neutralize LMW heparin. (2) HRG showed the same results on anti-TH effect of both kinds of heparin, but could not neutralize the anti-F-Xa effect of LMW heparin on the same amount of HRG which neutralized that of UF heparin. Conclusion: Anti-F-Xa effect of. LMW heparin could not be easily neutralized by pf-4 or HRG compared with that of UF heparin.

Recombinant Human FVIIa Reduces Heparin and Low Molecular Weight Heparin (LMWH)-Induced Bleeding in Rats.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2149-2149
Author(s):  
Brian Lauritzen ◽  
Mikael Tranholm ◽  
Peter B. Johansen ◽  
Mirella Ezban
Keyword(s):  
Molecular Weight ◽  
Blood Loss ◽  
Low Molecular Weight Heparin ◽  
Bleeding Time ◽  
Statistical Significance ◽  
Thrombin Inhibitors ◽  
Low Molecular Weight ◽  
Similar Response ◽  
Post Test ◽  
Observation Period

Abstract Recombinant human FVIIa (rFVIIa, NovoSeven, Novo Nordisk A/S) is approved for treatment of bleeding in hemophilia patients with inhibitors. Recent data indicate that rFVIIa is useful in other bleeding conditions. Heparin and low molecular weight heparin (LMWH) are widely used for anticoagulant management of venous thromboembolic events. Both agents can however cause uncontrollable bleeding. While protamine can reverse the anticoagulant effect of heparin no effective antidote for LMWH is currently available. We have tested if rFVIIa was capable of reducing the bleeding caused by either heparin or LMWH in a rat tail bleeding model. We pre-treated rats with a single dose of either heparin (Heparin, Leo; 200 IU/kg; i.v.) or LMWH (tinzaparin; Innohep, Leo; 500 IU/kg; i.v.), which significantly prolonged total bleeding time following tail transection (table 1). Similarly, blood loss increased significantly by pre-treatment with heparin and tinzaparin (table 2). rFVIIa, intravenously injected 5 minutes after induction of tail bleeding in doses of 5, 10 and 20 mg/kg (n=8), dose-dependently reduced bleeding time of the heparin-induced bleeding, reaching statistical significance at 20 mg/kg (table 1). In accordance, blood loss decreased significantly by treatment with 10 and 20 mg/kg rFVIIa (table 2). A similar response was seen in the tinzaparin pre-treated animals with a dose-dependent decrease in bleeding time (table 1), and a significant decrease in blood loss at 10 and 20 mg/kg rFVIIa (table 2). Table 1. Total bleeding time (s) Group Heparin 200 IU/kg (n=8)# Tinzaparin 500 IU/kg (n=9)# Data are analyzed using Mann-Whitneys U-test (A-B) or Kruskall-Wallis test with Dunn’s post-test (B-E). Asterisks indicate statistical significance at: *: p<0.05; **: p<0.01 and ***: p<0.001. #observation period 1800 s. A: No anticoagulant 293 ± 68 542 ± 180 B: Anticoag.+Vehicle 1668 ± 83 ***vs. A 1800 ± 0 ***vs. A C: Anticoag.+5 mg/kg rFVIIa 1194 ± 182 1732 ± 45 D: Anticoag.+10 mg/kg rFVIIa 1023 ± 230 1483 ± 152 E: Anticoag.+20 mg/kg rFVIIa 448 ± 66 **vs. B 1038 ± 206 *vs. B Table 2. Blood loss (nmol hemoglobin/ml) Group Heparin 200 IU/kg (n=8)# Tinzaparin 500 IU/kg (n=9)# Data are mean ± SEM. Data are analyzed after log transformation using Student’s t-test (A-B) or one-way ANOVA with Bonferroni’s post-test (B-E). Asterisks indicate statistical significance at: *: p<0.05; **: p<0.01 and ***: p<0.001. #observation period 1800 s. A: No anticoagulant 4.2 ± 4.0 4.9 ± 4.9 B: Anticoag.+Vehicle 53 ± 19 **vs. A 151 ± 37 ***vs. A C: Anticoag.+5 mg/kg rFVIIa 10.6 ± 5.6 32.3 ± 10.3 D: Anticoag.+10 mg/kg rFVIIa 0.73 ± 0.34 **vs. B 7.7 ± 2.8 ***vs. B E: Anticoag.+20 mg/kg rFVIIa 4.0 ± 1.9 *vs. B 22.6 ± 9.4 *vs. B This study illustrates the pharmacological effect of rFVIIa in the presence of heparin and LMWH and the results indicate that rFVIIa may be an effective way to treat heparin and LMWH induced bleeding, however the dose requirements are specific for the rat and cannot be extrapolated to other species. Future studies will investigate the hemostatic effect of rFVIIa in bleedings induced by coumarin analogues, thrombin inhibitors, factor Xa inhibitors, and platelet inhibitors.

scholarly journals Lipoprotein-associated coagulation inhibitor (LACI) is a cofactor for heparin: synergistic anticoagulant action between LACI and sulfated polysaccharides

Blood ◽  
1992 ◽  
Vol 79 (2) ◽  
pp. 430-438
Author(s):  
TC Wun
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Dermatan Sulfate ◽  
Factor Viia ◽  
Threshold Concentration ◽  
Sulfated Polysaccharides ◽  
Low Molecular Weight ◽  
Dependent Manner ◽  
Normal Plasma ◽  
Coagulation Inhibitor

Lipoprotein-associated coagulation inhibitor (LACI) is a plasma-derived protein that inhibits tissue factor (TF)/factor VIIa-induced coagulation in a factor Xa-dependent manner. The roles of endogenous plasma LACI and exogenously added LACI and heparin, in the regulation of coagulation, initiated via the intrinsic and extrinsic pathways, were studied using the activated partial thromboplastin time (APTT) and the modified prothrombin time (PT) assays, respectively. Both LACI- depleted plasma and normal plasma have identical APTTs and similar prolongations of the APTT in response to heparin; both are fully anticoagulated (arbitrarily defined as clotting times of greater than 1 hour) at similar concentrations of heparin. These results indicate that heparin is an effective anticoagulant when coagulation is initiated by the intrinsic pathway and that endogenous LACI is not significantly involved in the regulation of this pathway. The PT of normal plasma is only marginally longer than that of LACI-depleted plasma in the absence of heparin, suggesting that endogenous plasma LACI has a very limited capacity to inhibit TF-induced clotting. However, in the presence of heparin, the PTs of LACI-depleted plasma and normal plasma are different. Prolongation of the PT occurred only moderately and linearly with increasing concentrations of heparin in LACI-depleted plasma. In contrast, normal plasma showed a greater extent of PT prolongation in response to heparin and the plasma became fully anticoagulated at a certain threshold concentration of heparin. These results suggest that LACI serves as a cofactor for heparin and thus greatly enhances the inhibition of TF-induced coagulation. LACI-depleted plasma was supplemented with purified recombinant LACI and/or heparin and the effects on TF-induced clotting were studied. A combination of LACI and heparin greatly enhanced anticoagulation compared with LACI or heparin alone. Many sulfated polysaccharides were also found to enhance the LACI-dependent inhibition of TF-induced clotting. By weight, the relative potencies of these compounds are: low molecular weight heparin (mean Mr, 5,100) greater than unfractionated heparin greater than low molecular weight heparin (mean Mr, 3,700) greater than pentosan polysulfate greater than dermatan sulfate greater than dextran sulfate greater than heparan sulfate. Based on the above results, it is concluded that LACI is a cofactor for heparin in the inhibition of TF- induced clotting and that LACI and sulfated polysaccharides act synergistically in whole plasma.

Human Urinary Soluble Thrombomodulin (MR-33) Improves Disseminated Intravascular Coagulation without Affecting Bleeding Time in Rats: Comparison with Low Molecular Weight Heparin

1997 ◽  
Vol 77 (04) ◽  
pp. 789-795 ◽  
Author(s):  
Yasuo Takahashi ◽  
Yoshitaka Hosaka ◽  
Kazunori Imada ◽  
Takehiro Adachi ◽  
Hiromi Niina ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Disseminated Intravascular Coagulation ◽  
Low Molecular Weight Heparin ◽  
Bleeding Time ◽  
Low Molecular Weight ◽  
Soluble Thrombomodulin ◽  
Intravascular Coagulation ◽  
Significant Prolongation ◽  
Dose Dependent Fashion ◽  
Dose Dependent

SummaryWe compared the antithrombotic and hemorrhagic effects of naturally existing human urinary soluble thrombomodulin (MR-33) with those of low molecular weight heparin (LMW-heparin) in rats. In in vitro experiments, MR-33 prolonged APTT in a dose-dependent fashion; its effect in this respect was as potent as that of LMW-heparin, but it was less potent than unfractionated heparin (UF-heparin). MR-33 was effective on endotoxin- or thromboplastin-induced disseminated intravascular coagulation (DIC) in rats. In both DIC models, infusion of MR-33 improved hematological abnormalities compatible with DIC in a dose-dependent fashion without excessive prolongation effect on APTT. Although LMW-heparin and UF-heparin also improved both DIC models, excessive prolongation of APTT was observed at high doses. It is well-known that the excessive prolongation of APTT with antithrombotic drugs like heparins is an index for hemorrhage, which is a major side effect in the treatment of DIC. We therefore further compared the antithrombotic (Benefit: dose required for 50% inhibition of fibrinogen decrease: ED50) and hemorrhagic (Risk: minimum dose required for significant prolongation of bleeding time) effects of MR-33 and LMW-heparin in the thromboplastin-induced DIC model. As a result, Benefit-Risk ratio was 1:27 for MR-33 and 1:3 for LMW heparin. These results indicate that MR-33 may be a clinically useful antithrombotic agent with reduced risk for hemorrhage compared with LMW-heparin.

SUBCUTANEOUS PHARMACOKINETICS/PHARMACODYNAMICS OF A LOW MOLECULAR WEIGHT DERIVATIVE (RD 11885) AND UNFRACTIONATED HEPARIN (PM 16885) IN PRIMATES

1987 ◽  
Author(s):  
R Norm ◽  
J Fareed ◽  
I Silber ◽  
A Belo ◽  
R Fenchel ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Low Molecular Weight Heparin ◽  
Bleeding Time ◽  
Ex Vivo ◽  
Factor Xa ◽  
Repeated Administration ◽  
Treated Group ◽  
Low Molecular Weight ◽  
Thrombin Time

Subcutaneous pharmacokinetics/pharmacodynamics of a depolymerized low molecular weight heparin (RD 11885) and an unfractionated porcine mucosal heparin (PM 16885) were studied in primates (Macaca mulatta) at 0.5, 1.0 and 2.5 mg/kg/24 hr for 10 days after repeated administration. Ex vivo actions were determined using partial thromboplastin time (APTT), thrombin time (TT), IieptestR time (HT) , anti-factor Xa and anti-factor Ila assays at various time periods. Platelet counts and bleeding times were also measured. The cumulative bioavailability of RD 11885 calculated ex vivo was found to be 2-3 fold higher than PM 16885. The RD 11885 treated group exhibited a clear dissociation of the anti-factor Xa and anti-factor Ila activities. The biological half-life of RD 11885 was significantly greater than PM 16885 in all assays. No staircasing phenomenon was observed with either agent. A desensitization of the PM 16885 effects was observed. Neither agent produced any effect on the bleeding time or platelet count at any time. The pharmacokinetics/pharmacodynamics of RD 11885 were uniform and allowed the calculation of various pharmacologic parameters, whereas inconsistent results were obtained with PM 16885. These results demonstrate that this low molecular weight heparin exhibits better and more predictable bioavailability, in contrast to unfractionated heparin.

Sign in / Sign up

Export Citation Format

Share Document