Multi-Cellular Activation In Vivo by Endotoxin in Humans – Limited Protection by Adenosine Infusion

2000 ◽  
Vol 84 (09) ◽  
pp. 381-387 ◽  
Author(s):  
Nailin Li ◽  
Anne Soop ◽  
Alf Sollevi ◽  
Paul Hjemdahl
Keyword(s):  
Von Willebrand Factor ◽  
Thrombin Generation ◽  
Platelet Reactivity ◽  
Adenosine Infusion ◽  
Cellular Activation ◽  
Soluble P ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Secretion

SummaryThe influence of adenosine infusion (40 µg/kg/min for 4 h) on inflammatory and hemostatic parameters was investigated in healthy males without (n = 10) or with (n = 11) intravenous endotoxin injection (4 ng/kg). Without endotoxin, adenosine elevated circulating leukocytes and circulating platelet-leukocyte aggregates. Endotoxin activated platelets and leukocytes in vivo. Platelet activation was seen as slightly increased platelet P-selectin expression, decreased platelet counts, and elevated plasma soluble P-selectin (from 39.6 ± 3.4 to 68.9 ± 6.6 ng/ml; P <0.01). Leukocyte activation was evidenced by increased CD11b expression (from MFI of 0.54 ± 0.02 to 2.21 ± 0.17; P <0.01) and plasma elastase levels (from 25.3 ± 2.5 to 169.3 ± 22.5 ng/ml; P <0.01). Endotoxin also enhanced platelet and leukocyte responsiveness to in vitro stimulation. Endotoxin induced von Willebrand factor secretion (from 92 ± 8 units to 265 ± 19 units at 4 h; P <0.001) and enhanced thrombin generation in vivo. Endotoxin induced leukocytosis and thus increased circulating platelet-leukocyte, mainly platelet-neutrophil, aggregates. Adenosine caused slight attenuation of platelet reactivity to agonist stimulation, enhanced the endotoxin-induced leukocytosis, and detained more platelet-leukocyte aggregates in circulation, but did not attenuate endotoxin-induced neutrophil elastase secretion, von Willebrand factor secretion, or thrombin generation. Thus, endotoxemia induces multi-cellular activation in vivo. Adenosine inhibits leukocyte adhesion and extravasation, and mildly attenuates platelet responsiveness and soluble P-selectin release. Adenosine has the potential of becoming a therapeutic antiinflammatory drug, but an optimal treatment strategy needs to be developed.

The NFY Transcription Factor Mediates Induction of the von Willebrand Factor Promoter by Irradiation

2001 ◽  
Vol 85 (05) ◽  
pp. 837-844 ◽  
Author(s):  
Angela Bertagna ◽  
Nadia Jahroudi
Keyword(s):  
Transcription Factor ◽  
Von Willebrand Factor ◽  
Thrombus Formation ◽  
Core Promoter ◽  
Transcriptional Level ◽  
Cis Acting ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Secretion

SummaryIonizing irradiation in patients is proposed to cause thrombus formation. An increase in von Willebrand factor secretion in response to irradiation is a major contributing factor to thrombus formation. We have previously reported that the increased VWF secretion in response to irradiation is mediated at the transcriptional level. The VWF core promoter fragment (sequences –90 to +22) was shown to contain the necessary cis-acting element(s) to mediate the irradiation response of the VWF gene. Here we report that a CCAAT element in the VWF promoter is the cis-acting element necessary for irradiation induction and that the NFY transcription factor interacts with this element. These analyses demonstrate that inhibition of NFY’s interaction with the CCAAT element abolishes the irradiation induction of the VWF promoter. These results provide a novel role for NFY and add this factor to the small list of irradiation-responsive transcription factors. Coimmunoprecipitation experiments demonstrated that NFY is associated with the histone acetylase P/CAF in vivo and that irradiation resulted in an increased association of NFY with coactivator P/CAF. We propose that irradiation induction of the VWF promoter involves a mechanism resulting in increased recruitment of the coactivator P/CAF to the promoter via the NFY transcription factor.

Body Mass Index and Plasma P-Selectin before Coronary Stenting Predict High Residual Platelet Reactivity at 6 Months on Dual Antiplatelet Therapy

Cardiology ◽  
2018 ◽  
Vol 139 (2) ◽  
pp. 132-136 ◽  
Author(s):  
Elena Z. Golukhova ◽  
Marina V. Grigoryan ◽  
Mariya N. Ryabinina ◽  
Naida I. Bulaeva ◽  
Victor L. Serebruany
Keyword(s):  
Body Mass Index ◽  
Antiplatelet Therapy ◽  
Von Willebrand Factor ◽  
Dual Antiplatelet Therapy ◽  
Light Transmission ◽  
Platelet Reactivity ◽  
Light Transmission Aggregometry ◽  
Soluble P ◽  
Von Willebrand ◽  
Willebrand Factor

Background: High residual platelet reactivity (HRPR) during dual antiplatelet therapy (DAPT) may impact clinical outcomes following percutaneous coronary interventions (PCI). However, whether any biomarkers assessed before PCI at DAPT loading may predict delayed maintenance HRPR is not clear. Objective: The aim of this study was to determine whether conventional clinical or laboratory indices at loading before stenting may predict HRPR at 6 months of maintenance DAPT. Methods: The study was designed on a single-center prospective cohort, and included 94 pre-PCI patients. All patients underwent elective PCI with drug-eluting stent implantation, and received DAPT with aspirin and clopidogrel. Platelet reactivity was assessed with 5 μmol/L of adenosine diphosphate-induced light transmission aggregometry before PCI, but after 24 h of DAPT loading, and repeated at 6 months. Baseline clinical characteristics, CYP2C19 polymorphism, C-reactive protein, soluble P-selectin, CD40L, interleukin-6, PAI-1 levels, and von Willebrand factor activity were analyzed. Results: The incidence (light transmission aggregometry <50%) of prestent HRPR was 16%. By univariate regression, body mass index (BMI; p = 0.02), total cholesterol (p = 0.01), low-density lipoproteins (p = 0.004), CYP2C19*2 allele carriage (p = 0.006), soluble P-selectin (p = 0.009), and von Willebrand factor (p = 0.04) were linked to future HRPR. However, multivariate regression analysis suggested that only BMI and P-selectin were independent predictors of HRPR. Conclusions: Platelet reactivity before elective stenting is associated with numerous biomarkers; however, only BMI and soluble P-selectin were independent predictors of future HRPR during maintenance-phase DAPT. This may be important for future tailored antiplatelet strategies in patients with metabolic syndrome and diabetics.

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.

Soluble P-selectin, Thrombocytopenia and von Willebrand Factor in HIV Infected Patients

1997 ◽  
Vol 77 (06) ◽  
pp. 1221-1222 ◽  
Author(s):  
Andrew D Blann ◽  
Martine Seigneur ◽  
Joel Constans ◽  
Jean Luc Pellegrin ◽  
Claude Conri
Keyword(s):  
Von Willebrand Factor ◽  
Soluble P ◽  
Von Willebrand ◽  
Willebrand Factor

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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