von Willebrand Factor Predicts Mortality in ACS Patients Treated with Potent P2Y12 Antagonists and is Inhibited by Aptamer BT200 Ex Vivo

2020 ◽  
Vol 120 (09) ◽  
pp. 1282-1290
Author(s):  
Katarina D. Kovacevic ◽  
Bernd Jilma ◽  
Shuhao Zhu ◽  
James C. Gilbert ◽  
Max-Paul Winter ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Plasma Levels ◽  
Ex Vivo ◽  
Dependent Manner ◽  
Platelet Inhibitors ◽  
Concentration Dependent Manner ◽  
High Shear Rates ◽  
P2y12 Antagonists ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Background von Willebrand factor (VWF) is crucial for arterial thrombosis and its plasma levels are increased in acute coronary syndromes (ACSs). The effects of conventional platelet inhibitors are compromised by elevated VWF under high shear rates. BT200 is a third-generation aptamer that binds and inhibits the A1 domain of human VWF. This article aims to study whether VWF is a predictor of mortality in ACS patients under potent P2Y12 blocker therapy and to examine the effects of a VWF inhibiting aptamer BT200 and its concentrations required to inhibit VWF in plasma samples of patients with ACS. Methods VWF activity was measured in 320 patients with ACS, and concentration effect curves of BT200 were established in plasma pools containing different VWF concentrations. Results Median VWF activity in patients was 170% (interquartile range % confidence interval [CI]: 85–255) and 44% of patients had elevated (> 180%) VWF activity. Plasma levels of VWF activity predicted 1-year (hazard ratio [HR]: 2.68; 95% CI: 1.14–6.31; p < 0.024) and long-term (HR: 2.59; 95% CI: 1.10–6.09) mortality despite treatment with potent platelet inhibitors (dual-antiplatelet therapy with aspirin and prasugrel or ticagrelor). Although half-maximal concentrations were 0.1 to 0.2 µg/mL irrespective of baseline VWF levels, increasing concentrations (0.42–2.13 µg/mL) of BT200 were needed to lower VWF activity to < 20% of normal in plasma pools containing increasing VWF activity (p < 0.001). Conclusion VWF is a predictor of all-cause mortality in ACS patients under contemporary potent P2Y12 inhibitor therapy. BT200 effectively inhibited VWF activity in a target concentration-dependent manner.

scholarly journals Physiologic cleavage of von Willebrand factor by a plasma protease is dependent on its conformation and requires calcium ion

Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4235-4244 ◽  
Author(s):  
HM Tsai
Keyword(s):  
Shear Stress ◽  
Von Willebrand Factor ◽  
Fluorescence Emission ◽  
Partial Recovery ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Proteolytic Resistance ◽  
Normal Plasma ◽  
Von Willebrand ◽  
Willebrand Factor

von Willebrand factor (vWF) in the circulation is subjected to proteolysis. In a recent study, we reported that normal plasma contains a protease activity that cleaves vWF in a shear-dependent manner, causing a decrease in its multimer size while generating dimers of the 140-kD and the 176-kD fragments indistinguishable from those found in normal plasma. In this study, the plasma protease has been partially purified and characterized and the role of vWF conformation in its cleavage by the protease has been further investigated. Guanidine HCl caused unfolding of vWF in a concentration-dependent manner, resulting in a shift in its fluorescence emission maxima to longer wavelengths. A dramatic increase in its proteolytic susceptibility was seen at 1.1 to 1.2 mol/L guanidine HCl, a concentration causing only a 3- to 4-nm shift in vWF emission maxima. Although vWF molecules refolded as guanidine HCl was removed by dialysis, the refolding was accompanied only by a partial recovery of the proteolytic resistance. The plasma protease, partially purified by approximately 900 folds by Sephacryl S- 300 HR gel filtration, Matrex gel orange A dye affinity chromatography, and Q Sepharose anion exchange, had a molecular mass of approximately 200 kD and was inhibited by EDTA, EGTA, or 1,10-phenanthroline. The inhibition by EGTA or EDTA could be reversed by Ca2+ but not by mg2+. It was not inhibited by a panel of synthetic and natural protease inhibitors or adsorbed by gelatin-agarose, and it was present in plasmas deficient in proteins involved in coagulation and anticoagulation. The vWF fragments generated by the protease, as mapped by peptide-specific antibodies VP-1 and LJ-7745, were in distinguishable from the natural fragments but distinct from those produced by plasmin. High molecular weight endothelial vWF, after exposure to guanidine HCLI or high shear stress, was cleaved by the protease to smaller forms. These results support the model that endothelial secreted vWF is converted to multimers by a novel plasma metalloproteinase. Although native vWF exists in a conformation relatively resistant to cleavage, an alteration in the conformation by shear stress can lead to enhanced proteolytic susceptibility. This model may explain the decrease in vWF multimer sizes in various clinical conditions.

N-Acetyl Cysteine Reduces von Willebrand Factor Multimer Size In Vitro and In Vivo.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 420-420
Author(s):  
Junmei Chen ◽  
Francisca C. Gushiken ◽  
Leticia Nolasco ◽  
Joel F. Moake ◽  
Jose A. Lopez
Keyword(s):  
Von Willebrand Factor ◽  
Chronic Obstructive Lung Disease ◽  
Chronic Obstructive ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Acetyl Cysteine ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract von Willebrand factor (VWF) shares a similar domain structure with many polymeric mucins, including the presence of D domains and a C-terminal cysteine knot, which allows these molecules to form polymeric structures that can reach immense sizes. Precipitation of polymeric lung mucins complicates the clinical course of cystic fibrosis and chronic obstructive lung disease, and in both cases the viscosity of the inspissated mucus can be reduced by treatment with N-acetyl cysteine (NAC), which presumably reduces the size of the mucin polymers by reducing sensitive disulfide bonds. Because of the similarity of VWF and mucin multimers, we examined whether NAC could also reduce VWF multimer size both in vitro and in vivo. In vitro, we incubated NAC at different concentrations and for different times with ultra-large VWF multimers (ULVWF) isolated from endothelial cell supernatant and examined the effect on multimer size using agarose gel electrophoresis. NAC reduced ULVWF size in a time- and concentration-dependent manner, with the peak effect reached at 5 min and at concentration of 0.5 mM. We then examined the effect of NAC on ULVWF/platelet “strings” formed on the surface of histamine-activated endothelial cells by perfusing the strings with NAC solutions. At 1 mM, NAC eliminated almost all of the adherent strings within 5 minutes. We next examined the effect of NAC in vivo by following VWF multimer size with time in C57B/6 injected with NAC either intraperitoneally or intravenously. NAC, at a single dose of 500 mg/kg, induced a sustained reduction in VWF multimer size in the treated mice within 4 hours after injection. The effects lasted up to 8 hours. These results suggest that NAC may be a rapid, safe, and effective treatment for patients suspected of suffering from thrombotic thrombocytopenic purpura, a disorder characterized by a failure to process ULVWF.

scholarly journals Collagen-factor VIII/von Willebrand factor protein interaction

Blood ◽  
1984 ◽  
Vol 63 (6) ◽  
pp. 1291-1298
Author(s):  
CM Kessler ◽  
CM Floyd ◽  
ME Rick ◽  
DM Krizek ◽  
SL Lee ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Protein Interaction ◽  
Type I ◽  
Dependent Manner ◽  
Similar Time ◽  
Concentration Dependent Manner ◽  
Normal Plasma ◽  
Von Willebrand ◽  
Willebrand Factor

Factor VIII/von Willebrand factor (FVIII/vWF) protein interaction with collagen was studied by incubating plasma or purified FVIII/vWF with purified type I fibrillar collagen. Collagen adsorbed FVIII/vWF activities in a similar time and concentration-dependent manner from normal plasma, plasmas from classical and variant type von Willebrand's disease (vWD), and from purified FVIII/vWF. Incubation with denatured collagen or fibrin, produced in the presence or absence of fibronectin, showed no adsorption of FVIII/vWF. Examination of the multimeric structure of the remaining unadsorbed FVIII/vWF protein by agarose gel electrophoresis and autoradiography showed that the largest multimers had been adsorbed to the collagen. Studies of the adsorbed FVIII/vWF protein when eluted from collagen showed that it complemented the alterations in multimeric structure observed in the supernatants following collagen exposure. The multimeric structure of normal plasma following collagen adsorption resembled that of unadsorbed type IIb plasma; however, the collagen-adsorbed normal plasma did not produce enhanced ristocetin-induced platelet aggregation ( RIPA ). This phenomenon, therefore, must not be due solely to absence of large multimers from type IIb FVIII/vWF protein. The adsorbed multimers of FVIII/vWF protein may act as a subendothelial collagen-platelet bridge to promote primary hemostasis.

scholarly journals Collagen-factor VIII/von Willebrand factor protein interaction

Blood ◽  
1984 ◽  
Vol 63 (6) ◽  
pp. 1291-1298 ◽  
Author(s):  
CM Kessler ◽  
CM Floyd ◽  
ME Rick ◽  
DM Krizek ◽  
SL Lee ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Protein Interaction ◽  
Type I ◽  
Dependent Manner ◽  
Similar Time ◽  
Concentration Dependent Manner ◽  
Normal Plasma ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Factor VIII/von Willebrand factor (FVIII/vWF) protein interaction with collagen was studied by incubating plasma or purified FVIII/vWF with purified type I fibrillar collagen. Collagen adsorbed FVIII/vWF activities in a similar time and concentration-dependent manner from normal plasma, plasmas from classical and variant type von Willebrand's disease (vWD), and from purified FVIII/vWF. Incubation with denatured collagen or fibrin, produced in the presence or absence of fibronectin, showed no adsorption of FVIII/vWF. Examination of the multimeric structure of the remaining unadsorbed FVIII/vWF protein by agarose gel electrophoresis and autoradiography showed that the largest multimers had been adsorbed to the collagen. Studies of the adsorbed FVIII/vWF protein when eluted from collagen showed that it complemented the alterations in multimeric structure observed in the supernatants following collagen exposure. The multimeric structure of normal plasma following collagen adsorption resembled that of unadsorbed type IIb plasma; however, the collagen-adsorbed normal plasma did not produce enhanced ristocetin-induced platelet aggregation ( RIPA ). This phenomenon, therefore, must not be due solely to absence of large multimers from type IIb FVIII/vWF protein. The adsorbed multimers of FVIII/vWF protein may act as a subendothelial collagen-platelet bridge to promote primary hemostasis.

scholarly journals The cooperative activity between the carboxyl-terminal TSP1 repeats and the CUB domains of ADAMTS13 is crucial for recognition of von Willebrand factor under flow

Blood ◽  
2007 ◽  
Vol 110 (6) ◽  
pp. 1887-1894 ◽  
Author(s):  
Ping Zhang ◽  
Weilan Pan ◽  
Ann H. Rux ◽  
Bruce S. Sachais ◽  
X. Long Zheng
Keyword(s):  
Von Willebrand Factor ◽  
Dissociation Constants ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cooperative Activity ◽  
Carboxyl Terminal ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract ADAMTS13 cleaves von Willebrand factor (VWF) between Tyr1605 and Met1606 residues at the central A2 subunit. The amino-terminus of ADAMTS13 protease appears to be sufficient to bind and cleave VWF under static and denatured condition. However, the role of the carboxyl-terminus of ADAMTS13 in substrate recognition remains controversial. Present study demonstrates that ADAMTS13 cleaves VWF in a rotation speed– and protease concentration–dependent manner on a mini vortexer. Removal of the CUB domains (delCUB) or truncation after the spacer domain (MDTCS) significantly impairs its ability to cleave VWF under the same condition. ADAMTS13 and delCUB (but not MDTCS) bind VWF under flow with dissociation constants (KD) of about 50 nM and about 274 nM, respectively. The isolated CUB domains are neither sufficient to bind VWF detectably nor capable of inhibiting proteolytic cleavage of VWF by ADAMTS13 under flow. Addition of the TSP1 5-8 (T5-8CUB) or TSP1 2-8 repeats (T2-8CUB) to the CUB domains restores the binding affinity toward VWF and the inhibitory effect on cleavage of VWF by ADAMTS13 under flow. These data demonstrate directly and quantitatively that the cooperative activity between the middle carboxyl-terminal TSP1 repeats and the distal carboxyl-terminal CUB domains may be crucial for recognition and cleavage of VWF under flow.

scholarly journals Inhibition of platelet adhesion to fibronectin, fibrinogen, and von Willebrand factor substrates by a synthetic tetrapeptide derived from the cell-binding domain of fibronectin

Blood ◽  
1985 ◽  
Vol 66 (4) ◽  
pp. 946-952 ◽  
Author(s):  
DM Haverstick ◽  
JF Cowan ◽  
KM Yamada ◽  
SA Santoro
Keyword(s):  
Amino Acids ◽  
Von Willebrand Factor ◽  
Synthetic Peptides ◽  
Dependent Manner ◽  
Cell Binding ◽  
Binding Region ◽  
Concentration Dependent Manner ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Adhesion Of Platelets

The role in platelet function of the cell-binding region of fibronectin was explored by the use of synthetic peptides. The prototypical peptide gly-arg-gly-asp-ser was capable of inhibiting thrombin-induced platelet aggregation without altering the degree of platelet activation as judged by the secretion of 14C-serotonin. The peptide also effectively inhibited, in a concentration-dependent manner, the binding of radiolabeled fibronectin to platelets and the adhesion of platelets to fibronectin substrates. The smallest peptide from the cell-binding region of fibronectin which retained full activity was arg-gly-asp-ser. Transposition of amino acids or conservative substitutions of amino acids within this short sequence resulted in inactive peptides. Peptides containing the arg-gly-asp-ser sequence were also capable of inhibiting the adhesion of platelets to fibrinogen and von Willebrand factor substrates. Examination of the entire panel of synthetic peptides for ability to inhibit adhesion to fibrinogen or von Willebrand factor substrates revealed the same structure-function relationships that had been determined in the studies with fibronectin.

scholarly journals Inhibition of platelet adhesion to fibronectin, fibrinogen, and von Willebrand factor substrates by a synthetic tetrapeptide derived from the cell-binding domain of fibronectin

Blood ◽  
1985 ◽  
Vol 66 (4) ◽  
pp. 946-952 ◽  
Author(s):  
DM Haverstick ◽  
JF Cowan ◽  
KM Yamada ◽  
SA Santoro
Keyword(s):  
Amino Acids ◽  
Von Willebrand Factor ◽  
Synthetic Peptides ◽  
Dependent Manner ◽  
Cell Binding ◽  
Binding Region ◽  
Concentration Dependent Manner ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Adhesion Of Platelets

Abstract The role in platelet function of the cell-binding region of fibronectin was explored by the use of synthetic peptides. The prototypical peptide gly-arg-gly-asp-ser was capable of inhibiting thrombin-induced platelet aggregation without altering the degree of platelet activation as judged by the secretion of 14C-serotonin. The peptide also effectively inhibited, in a concentration-dependent manner, the binding of radiolabeled fibronectin to platelets and the adhesion of platelets to fibronectin substrates. The smallest peptide from the cell-binding region of fibronectin which retained full activity was arg-gly-asp-ser. Transposition of amino acids or conservative substitutions of amino acids within this short sequence resulted in inactive peptides. Peptides containing the arg-gly-asp-ser sequence were also capable of inhibiting the adhesion of platelets to fibrinogen and von Willebrand factor substrates. Examination of the entire panel of synthetic peptides for ability to inhibit adhesion to fibrinogen or von Willebrand factor substrates revealed the same structure-function relationships that had been determined in the studies with fibronectin.

Proteolytic inactivation of ADAMTS13 by thrombin and plasmin

Blood ◽  
2005 ◽  
Vol 105 (3) ◽  
pp. 1085-1093 ◽  
Author(s):  
James T. B. Crawley ◽  
Jonathan K. Lam ◽  
James B. Rance ◽  
Luigina R. Mollica ◽  
James S. O'Donnell ◽  
...  
Keyword(s):  
Vascular Injury ◽  
Von Willebrand Factor ◽  
Vascular System ◽  
Dependent Manner ◽  
Cleavage Sites ◽  
Adamts13 Activity ◽  
Concentration Dependent Manner ◽  
Soluble Thrombomodulin ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The multimeric size and the function of circulating von Willebrand factor are modulated via its proteolytic cleavage by the plasma metalloproteinase, ADAMTS13. It is unclear how ADAMTS13 activity is regulated within the vascular system. In the absence of a regulatory mechanism, ADAMTS13 activity might compromise platelet adhesion at sites of vascular injury. We hypothesized that at sites of vascular injury, ADAMTS13 activity could be regulated locally by coagulation proteinases. Initiation of coagulation in human plasma resulted in the disappearance of added full-length recombinant ADAMTS13. This loss was inhibited by hirudin. Using purified proteins, we showed that ADAMTS13 is proteolyzed at several cleavage sites by thrombin in a time- and concentration-dependent manner. Furthermore, this proteolysis ablated ADAMTS13 activity against purified von Willebrand factor. Preincubation of thrombin with soluble thrombomodulin, but not heparin, inhibited the proteolysis of ADAMTS13, suggesting the involvement of thrombin exosite I (and not exosite II) in ADAMTS13 recognition. Plasmin also cleaved ADAMTS13 into similar fragments, resulting in the loss of ADAMTS13 activity. This study demonstrates the susceptibility of ADAMTS13 to proteolytic inactivation and suggests possible roles for thrombin and plasmin at sites of vascular injury.

Asialo von Willebrand Factor Enhances Platelet Adhesion to Vessel Subendothelium

1988 ◽  
Vol 60 (01) ◽  
pp. 030-034 ◽  
Author(s):  
Eva Bastida ◽  
Juan Monteagudo ◽  
Antonio Ordinas ◽  
Luigi De Marco ◽  
Ricardo Castillo
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Human Albumin ◽  
Membrane Receptors ◽  
Shear Rates ◽  
High Shear Rates ◽  
Platelet Deposition ◽  
Platelet Spreading ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryNative von Willebrand factor (N-vWF) binds to platelets activated by thrombin, ADP or ristocetin. Asialo vWF (As-vWF) induces platelet aggregation in absence of platelet activators. N-vWF mediates platelet adhesion to vessel subendothelium at high shear rates. We have investigated the role of As-vWF in supporting platelet deposition to rabbit vessel subendothelium at a shear rate of 2,000 sec-1, using the Baumgartner perfusion system. We have studied the effects of the addition of As-vWF (from 2 to 12 μg/ml) to perfusates consisting of washed red blood cells, 4% human albumin and washed platelets. Our results show a significant increase in platelet deposition on subendothelium (p <0.01) in perfusions to which As-vWF had been added. Blockage of the platelet glycoproteins Ib and IIb/IIIa (GPIb and GPIIb/IIIa) by specific monoclonal antibodies (LJIb1 and LJCP8, respectively) resulted in a decrease of platelet deposition in both types of perfusates prepared with N-vWF and As-vWF. Our results indicate that As-vWF enhances platelet deposition to vessel subendothelium under flow conditions. Furthermore, they suggest that this effect is mediated by the binding of As-vWF to platelet membrane receptors, which in turn, promote platelet spreading and adhesion to the subendothelium.

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