Transfusion Requirements Are Correlated with the Degree of Proteolysis of von Willebrand Factor during Orthotopic Liver Transplantation

1997 ◽  
Vol 78 (02) ◽  
pp. 813-819 ◽  
Author(s):  
A Lattuada ◽  
P M Mannucci ◽  
C Chen ◽  
C Legnani ◽  
G Palareti
Keyword(s):  
Liver Transplantation ◽  
Orthotopic Liver Transplantation ◽  
Von Willebrand Factor ◽  
Bleeding Tendency ◽  
Excessive Bleeding ◽  
Transfusion Requirements ◽  
Activity Of Enzymes ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryDuring orthotopic liver transplantation (OLT) excessive bleeding is the main cause of death and graft failure. The acute bleeding tendency that accompanies OLT, particularly during the anhepatic period and after reperfusion of the graft, is due to the depletion or functional abnormalities of several hemostasis components caused by the enhanced activity of enzymes such as plasmin, trypsin and leukocyte proteases. We surmised that enhanced proteolysis might also cause abnormalities of von Willebrand factor (vWF), and that these abnormalities are implicated in the bleeding tendency that develops during OLT. Therefore, the pattern of vWF proteolysis was studied with 16 patients with chronic liver disease, in serial blood samples obtained before OLT, during the anhepatic stage, after graft reperfusion and at the end of the surgical procedure. vWF became markedly degraded during the anhepatic and reperfusion stages, as shown by the partial loss of high molecular weight multimers, the relative decrease of the intact 225 kD subunit and the increase of the native proteolytic fragments of 176 and 140 kD. Novel proteolytic fragments also became detectable. Using monoclonal antibody epitope mapping, it could be demonstrated that some of the proteolytic fragments corresponded in apparent molecular mass to those produced in vitro by incubating purified vWF with plasmin or elastase, but other fragments could not be attributed to these proteases. During the anhepatic and reperfusion stages there was a significant correlation between the degree of vWF degradation and the total amount of blood components transfused to replace blood losses. To evaluate whether or not vWF degradation could be controlled by the administration of a broad-spectrum protease inhibitor such as aprotinin, 5 patients were given a bolus dose of 500,000 U before surgery followed by 100,000 U/h during surgery, 5 were given a 2,000,000 U bolus followed by 500,000 U/h, and no aprotinin was given to the remaining 6 patients. There were no differences in the patterns or degrees of vWF degradation between patients treated with aprotinin or not. In conclusion, there is a marked degradation of a key hemostasis protein during OLT. These alterations may be of clinical significance, because they are correlated with the transfusion requirements.

scholarly journals Development of a Severe von Willebrand Factor/ADAMTS13 Dysbalance During Orthotopic Liver Transplantation

2009 ◽  
Vol 9 (5) ◽  
pp. 1189-1196 ◽  
Author(s):  
I. T. A. Pereboom ◽  
J. Adelmeijer ◽  
Y. van Leeuwen ◽  
H. G. D. Hendriks ◽  
R. J. Porte ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
Orthotopic Liver Transplantation ◽  
Von Willebrand Factor ◽  
Von Willebrand ◽  
Willebrand Factor

Intracellular Co-Localization of Factor VIII and Von Willebrand Factor Is Necessary for In Vivo FVIII Secretion.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 41-41 ◽  
Author(s):  
Patricia A. Lamont ◽  
Margaret V. Ragni
Keyword(s):  
Liver Transplantation ◽  
Factor Viii ◽  
Von Willebrand Factor ◽  
Hemophilia A ◽  
Liver Function Tests ◽  
Von Willebrand Disease ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Although the extracellular association of Factor VIII (FVIII) and Von Willebrand Factor (VWF) is well established, the intracellular interaction of FVIII and VWF is not well understood. Recently, the importance of intracellular co-localization of FVIII and VWF for in vitro FVIII secretion was demonstrated in endothelial cell lines. Whether intracellular co-localization of FVIII and VWF is required for in vivo FVIII secretion, however, is not known. We previously showed that liver transplantation leads to phenotypic cure of hemophilia A, by virtue of FVIII production in the allograft liver. Because FVIII is synthesized only in the allograft liver but not in endothelial cells of transplant recipients, and VWF is synthesized in extrahepatic tissue, this is an ideal model to study whether co-localization of FVIII and VWF is required for in vivo FVIII secretion. We, therefore, studied FVIII and VWF response after desmopression (DDAVP) infusion, administered at 0.3 mcg/kg by intravenous infusion over 30 minutes, in each of two men with severe hemophilia A (FVIII:C <0.01 U/ml) who had undergone orthotopic liver transplantation for endstage liver disease six months earlier. Both men had HIV and hepatitis C co-infection and were clinically well, with mildly elevated liver function tests, and FVIII:C levels >30% following transplantation. Coagulation studies, drawn before and after DDAVP, revealed that VWF:RCoF and VWF:Ag, but not FVIII:C, increased after DDAVP administration (see Table). The prolonged aPTT and correction in a 1:1 aPTT mix confirmed the absence of an inhibitor in these subjects. The lack of FVIII response to DDAVP supports previous in vitro work, and demonstrates for the first time that intracellular co-localization of FVIII and VWF is essential for in vivo FVIII secretion. These data also suggest that extrahepatic FVIII synthesis is necessary for in vivo response of the DDAVP releasable pool of FVIII. By contrast, co-localization does not appear to be necessary for VWF secretion. Although it is not possible to exclude that a chronic, exhaustive post-transplant increase in VWF may have limited VWF response to DDAVP, it is clear that FVIII did not increase following DDAVP. These findings have important implications for the design of gene therapies for hemophilia A and Von Willebrand Disease. Subject Demographic Sample aPTT aPTT mix FVIII:C VWF:RCoF VWF:Ag 01-BW 32yoM Hem A Pre-DDAVP 44.4 sec 37.7 sec 0.50 U/ml 2.17 U/ml 2.42 U/ml HIV+/HCV+ Post-DDAVP 44.8 sec 37.4 sec 0.48 U/ml 2.91 U/ml 2.91 U/ml 02-PB 36yoM Hem A Pre-DDAVP 49.5 sec 38.0 sec 0.32 U/ml 1.61 U/ml 2.16 U/ml HIV+/HCV+ Post-DDAVP 50.8 sec 38.5 sec 0.30 U/ml 2.20 U/ml 2.50 U/ml

Abnormal Structure of von Willebrand Factor in Myeloproliferative Syndrome Is Associated to Either Thrombotic or Bleeding Diathesis

1987 ◽  
Vol 58 (02) ◽  
pp. 753-757 ◽  
Author(s):  
M F López-Fernández ◽  
C López-Berges ◽  
R Martín ◽  
A Pardo ◽  
F J Ramos ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Proteinase Inhibitors ◽  
Relative Proportion ◽  
Variable Degree ◽  
Bleeding Diathesis ◽  
Myeloproliferative Syndrome ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryThe multimeric and subunit patterns of plasma von Willebrand factor (vWF) were analyzed in eight patients with myeloproliferative syndrome (MS) in order to investigate the possible existence of heterogeneity in the “in vivo” proteolytic cleavage of the protein, previously observed in this entity. Six patients lacked large vWF multimers, five of them having normal bleeding times (BT) and clinically documented episodes of thrombotic origin, whereas one patient had long BT and bleeding symptoms. Seven patients showed a relative increase in the 176 kDa subunit fragment while the 189 kDa polypeptide was increased in only one. In addition, another patient (and prior to any therapy) showed the presence of a new fragment of approximately 95 kDa which disappeared after Busulfan therapy. The collection of blood from these patients with proteinase inhibitors did not correct the abnormalities.The infusion of DDAVP to two patients with abnormal vWF was accompanied by: the appearance of larger vWF multimers which disappeared rapidly from plasma; an increase in the relative proportion of the satellite bands of each multimer and a further increase of the 176 kDa fragment. These data point to some heterogeneity in the vWF abnormality present in MS which may be related in part to a variable degree of proteolysis of vWF occurring “in vivo” rather than “in vitro”, and which may be associated to either a thrombotic or a bleeding diathesis. They also suggest that despite the presence of abnormal, already proteolyzed vWF, DDAVP-enhanced proteolysis occurs in MS to a similar extent to what is described in normal individuals.

The Genetic Defect of Type I von Willebrand Disease “Vicenza” Is Linked to the von Willebrand Factor Gene

1993 ◽  
Vol 69 (02) ◽  
pp. 173-176 ◽  
Author(s):  
Anna M Randi ◽  
Elisabetta Sacchi ◽  
Gian Carlo Castaman ◽  
Francesco Rodeghiero ◽  
Pier Mannuccio Mannucci
Keyword(s):  
Von Willebrand Factor ◽  
Autosomal Dominant ◽  
Genetic Defect ◽  
Von Willebrand Disease ◽  
Type I ◽  
Bleeding Tendency ◽  
Factor Gene ◽  
Low Levels ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryType I von Willebrand disease (vWD) Vicenza is a rare variant with autosomal dominant transmission, characterized by the presence of supranormal von Willebrand factor (vWF) multimers in plasma, similar to those normally found in endothelial cells and megakaryocytes. The patients have very low levels of plasma vWF contrasting with a mild bleeding tendency. The pathophysiology of this subtype is still unknown. The presence of supranormal multimers in the patients’ plasma could be due to a mutation in the vWF molecule which affects post-translational processing, or to a defect in the cells’ processing machinery, independent of the vWF molecule. In order to determne if type I vWD Vicenza is linked to the vWF gene, we studied six polymorphic systems identified within the vWF gene in two apparently unrelated families with type I vWD Vicenza. The results of this study indicate a linkage between vWF gene and the type I vWD Vicenza trait. This strongly suggests that type I vWD Vicenza is due to a mutation in one of the vWF alleles, which results in an abnormal vWF molecule that is processed to a lesser extent than normal vWF.

Adverse Influence of Cigarette Smoking on the Endothelium

1993 ◽  
Vol 70 (04) ◽  
pp. 707-711 ◽  
Author(s):  
Andrew D Blann ◽  
Charles N McCollum
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Tobacco Smoke ◽  
Lipid Peroxides ◽  
Short Exposure ◽  
Acute Effects ◽  
Adverse Influence ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryThe effect of smoking on the blood vessel intima was examined by comparing indices of endothelial activity in serum from smokers with that from non-smokers. Serum from smokers contained higher levels of von Willebrand factor (p <0.01), the smoking markers cotinine (p <0.02) and thiocyanate (p <0.01), and was more cytotoxic to endothelial cells in vitro (p <0.02) than serum from non-smokers. The acute effects of smoking two unfiltered medium tar cigarettes was to briefly increase von Willebrand factor (p <0.001) and cytotoxicity of serum to endothelial cells in vitro (p <0.005), but lipid peroxides or thiocyanate were not increased by this short exposure to tobacco smoke. Although there were correlations between von Willebrand factor and smokers consumption of cigarettes (r = 0.28, p <0.02), number of years smoking (r = 0.41, p <0.001) and cotinine (r = 0.45, p <0.01), the tissue culture of endothelial cells with physiological levels of thiocyanate or nicotine suggested that these two smoking markers were not cytotoxic. They are therefore unlikely to be directly responsible for increased von Willebrand factor in the serum of smokers. We suggest that smoking exerts a deleterious influence on the endothelium and that the mechanism is complex.

Autoantibody Selectively Inhibits Binding of von Willebrand Factor to Glycoprotein Ib. Recognition Site Is Located in the A1 Loop of von Willebrand Factor

1997 ◽  
Vol 77 (04) ◽  
pp. 760-766 ◽  
Author(s):  
Hiroshi Mohri ◽  
Etsuko Yamazaki ◽  
Zekou Suzuki ◽  
Toshikuni Takano ◽  
Shumpei Yokota ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Significant Inhibition ◽  
Von Willebrand Disease ◽  
Recognition Site ◽  
Severe Bleeding ◽  
Bleeding Tendency ◽  
Virtual Absence ◽  
Heavy Chains ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryA 20-year-old man with severe von Willebrand disease recently presented a progressive bleeding tendency, characterized recurrent subcutaneous hemorrhages and cerebral hemorrhage. Mixing and infusion studies suggested the presence of an inhibitor directed against vWF:RCo activity of von Willebrand factor (vWF) without significant inhibition of the FVIII:C. The inhibitor was identified as an antibody of IgG class. The inhibitor inhibited the interaction of vWF in the presence of ristocetin and that of asialo-vWF with GPIb while it partially blocked botrocetin-mediated interaction of vWF to GPIb. The inhibitor reacted with native vWF, the 39/34kDa fragment (amino acids [aa] 480/ 481-718) and the recombinant vWF fragment (MalE-rvWF508-704), but not with Fragment III-T2 (heavy chains, aa 273-511; light chains, aa 674-728). A synthetic peptide (aa 514-542) did not inhibit vWF-inhibitor complex formation. We conclude that this is the first autoantibody of class IgG from human origin that recognizes the sequence in the A1 loop of vWF, resulting in a virtual absence of functional vWF and a concomitant severe bleeding tendency although recognition site is different from the residues 514-542 which is crucial for vWF-GPIb interaction.

Epinephrine Induces von Willebrand Factor Release from Cultured Endothelial Cells: Involvement of Cyclic AMP-dependent Signalling in Exocytosis

1997 ◽  
Vol 77 (06) ◽  
pp. 1182-1188 ◽  
Author(s):  
Ulrich M Vischer ◽  
Claes B Wollheinn
Keyword(s):  
Endothelial Cells ◽  
Adenylate Cyclase ◽  
Von Willebrand Factor ◽  
Umbilical Vein ◽  
Free Calcium ◽  
Camp Content ◽  
Von Willebrand ◽  
Willebrand Factor

Summaryvon Willebrand factor (vWf) is released from endothelial cell storage granules after stimulation with thrombin, histamine and several other agents that induce an increase in cytosolic free calcium ([Ca2+]i). In vivo, epinephrine and the vasopressin analog DDAVP increase vWf plasma levels, although they are thought not to induce vWf release from endothelial cells in vitro. Since these agents act via a cAMP-dependent pathway in responsive cells, we examined the role of cAMP in vWf secretion from cultured human umbilical vein endothelial cells. vWf release increased by 50% in response to forskolin, which activates adenylate cyclase. The response to forskolin was much stronger when cAMP degradation was blocked with IBMX, an inhibitor of phosphodiesterases (+200%), whereas IBMX alone had no effect. vWf release could also be induced by the cAMP analogs dibutyryl-cAMP (+40%) and 8-bromo-cAMP (+25%); although their effect was weak, they clearly potentiated the response to thrombin. Epinephrine (together with IBMX) caused a small, dose-dependent increase in vWf release, maximal at 10-6 M (+50%), and also potentiated the response to thrombin. This effect is mediated by adenylate cyclase-coupled β-adrenergic receptors, since it is inhibited by propranolol and mimicked by isoproterenol. In contrast to thrombin, neither forskolin nor epinephrine caused an increase in [Ca2+]j as measured by fura-2 fluorescence. In addition, the effects of forskolin and thrombin were additive, suggesting that they act through distinct signaling pathways. We found a close correlation between cellular cAMP content and vWf release after stimulation with epinephrine and forskolin. These results demonstrate that cAMP-dependent signaling events are involved in the control of exocytosis from endothelial cells (an effect not mediated by an increase in [Ca2+]i) and provide an explanation for epinephrine-induced vWf release.

Mouse models to study von Willebrand factor structure-function relationships in vivo

2009 ◽  
Vol 29 (01) ◽  
pp. 17-20 ◽  
Author(s):  
I. Marx ◽  
I. Badirou ◽  
R. Pendu ◽  
O. Christophe ◽  
C. V. Denis
Keyword(s):  
Structure Function ◽  
Transient Expression ◽  
Von Willebrand Factor ◽  
Large Size ◽  
Mouse Hepatocytes ◽  
Function Relationship ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryVon Willebrand factor (VWF) structure-function relationship has been studied only through in vitro approaches. The VWF-deficient mouse model has been extremely useful to examine the in vivo function of VWF but does not allow a more subtle analysis of the relative importance of its different domains. However, considering the large size of VWF and its capacity to interact with various ligands in order to support platelet adhesion and aggregation, the necessity to evaluate independently these interactions appeared increasingly crucial. A recently developed technique, known as hydrodynamic injection, which allows transient expression of a transgene by mouse hepatocytes, proved very useful in this regard. Indeed, transient expression of various VWF mutants in VWF-deficient mice contributed to improve our knowledge about the role of VWF interaction with subendothelial collagens and with platelets receptors in VWF roles in haemostasis and thrombosis. These findings can provide new leads in the development of anti-thrombotic therapies.

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