scholarly journals Demonstration of Rickettsia conorii-induced endothelial injury in vivo by measuring circulating endothelial cells, thrombomodulin, and von Willebrand factor in patients with Mediterranean spotted fever [see comments]

Blood ◽  
1993 ◽  
Vol 82 (7) ◽  
pp. 2109-2116
Author(s):  
F George ◽  
P Brouqui ◽  
MC Boffa ◽  
M Mutin ◽  
M Drancourt ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Spotted Fever ◽  
Clinical Manifestations ◽  
Endothelial Injury ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rickettsia Conorii ◽  
Mediterranean Spotted Fever ◽  
Von Willebrand ◽  
Willebrand Factor

The endothelial cell (EC) is the primary target for Rickettsia conorii (RC) in Mediterranean spotted fever (MSF). Clinical manifestations such as thrombosis and vasculitis are mediated by pathologic changes localized in blood vessels. To study the in vivo endothelial injury induced by RC, markers of endothelial damage, including circulating EC (CEC), plasmatic thrombomodulin (TM), and von Willebrand factor (vWF), were investigated in 12 patients with MSF. CEC were counted in whole blood by a new immunomagnetic separation assay using a specific anti-EC antibody, S-Endo 1. Plasmatic TM and vWF antigens were measured by enzyme-linked immunosorbent assay. High levels of CEC and cell fragments were found in patients with a severe or malignant form of MSF. Sequential studies of CEC showed a decrease from 162 +/- 454 cells/mL before treatment to 6 +/- 7 cells/mL during treatment and recovery. Mean plasma TM and vWF levels that were also elevated before therapy (TM, 106 +/- 27 ng/mL; vWF, 420% +/- 164%) decreased progressively (TM, 55 +/- 43 ng/mL; vWF, 148% +/- 26%) during treatment. The measurement of cellular and molecular markers of vascular damage such as CEC, plasmatic TM, and vWF contributes to the definition of the Rickettsia-induced endothelial injury in vivo.

scholarly journals Demonstration of Rickettsia conorii-induced endothelial injury in vivo by measuring circulating endothelial cells, thrombomodulin, and von Willebrand factor in patients with Mediterranean spotted fever [see comments]

Blood ◽  
1993 ◽  
Vol 82 (7) ◽  
pp. 2109-2116 ◽  
Author(s):  
F George ◽  
P Brouqui ◽  
MC Boffa ◽  
M Mutin ◽  
M Drancourt ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Spotted Fever ◽  
Clinical Manifestations ◽  
Endothelial Injury ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rickettsia Conorii ◽  
Mediterranean Spotted Fever ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The endothelial cell (EC) is the primary target for Rickettsia conorii (RC) in Mediterranean spotted fever (MSF). Clinical manifestations such as thrombosis and vasculitis are mediated by pathologic changes localized in blood vessels. To study the in vivo endothelial injury induced by RC, markers of endothelial damage, including circulating EC (CEC), plasmatic thrombomodulin (TM), and von Willebrand factor (vWF), were investigated in 12 patients with MSF. CEC were counted in whole blood by a new immunomagnetic separation assay using a specific anti-EC antibody, S-Endo 1. Plasmatic TM and vWF antigens were measured by enzyme-linked immunosorbent assay. High levels of CEC and cell fragments were found in patients with a severe or malignant form of MSF. Sequential studies of CEC showed a decrease from 162 +/- 454 cells/mL before treatment to 6 +/- 7 cells/mL during treatment and recovery. Mean plasma TM and vWF levels that were also elevated before therapy (TM, 106 +/- 27 ng/mL; vWF, 420% +/- 164%) decreased progressively (TM, 55 +/- 43 ng/mL; vWF, 148% +/- 26%) during treatment. The measurement of cellular and molecular markers of vascular damage such as CEC, plasmatic TM, and vWF contributes to the definition of the Rickettsia-induced endothelial injury in vivo.

VON WILLEBRAND FACTOR (VWF) ANTIGENS IN URINE

1987 ◽  
Author(s):  
A M V Silveira ◽  
B Hessel ◽  
B Blombäck
Keyword(s):  
Monoclonal Antibodies ◽  
Von Willebrand Factor ◽  
High Performance ◽  
Molecular Size ◽  
Von Willebrand Disease ◽  
Enzyme Linked Immunosorbent Assay ◽  
Normal Urine ◽  
Von Willebrand ◽  
Willebrand Factor

Human urine was analyzed using a sensitive enzyme linked immunosorbent assay (ELISA) for von Willebrand factor (VWF) antigen. Urine of healthy persons contained VWF immunoreactivity. In the urine of a patient with severe von Willebrand disease, the VWF antigen was only detectable after intravenous infusion of VWF-Factor VIII concentrate. The VWF antigen in normal urine was analyzed by gel permeation high performance liquid chromatography (HPLC) and gel electrophoresis combined with immunoblotting. These analyses revealed three immunoreactive components of Mr 350 kDa, 60 kDa, and 20 kDa, respectively, the 60 kDa being the major component. Monoclonal antibodies of known specificity to VWF molecule were used in ELISA and immunoblotting to analyze urinary VWF. The three components reacted with an antibody to the central part of VWF, which is called fragment I, and contains the binding site for collagen. No significant immunoreac-tion was observed with monoclonal antibodies to the Nor C-terminal portions of VWF.VWF derivatives of molecular size similar to the largest urinary antigens were also observed in normal plasma. However, there is not an obvious relationship between these plasma forms and the products in urine since reduction of plasma and urine yields different products.These results indicate that VWF antigens excreted in normal urine are most likely fragments of VWF produced by limited degradation in vivo. This degradation preserves the central part of VWF molecule, the one which reacts with the antibody that blocks the binding of VWF to collagen.

High Levels of Plasma FVIII and vWF in the Toxic Epidemic Syndrome Patients

1989 ◽  
Vol 62 (02) ◽  
pp. 690-693
Author(s):  
M F López-Fernández ◽  
C López-Berges ◽  
J Fermoso ◽  
A Martín-Pascual ◽  
J J Sánchez-Hernández ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Clinical Manifestations ◽  
Chronic Phase ◽  
Multisystemic Disease ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen ◽  
Ristocetin Cofactor

SummaryFactor VIII and von Willebrand factor proteins were evaluated in 115 patients having the chronic phase of the Toxic Epidemic Syndrome (TES), a new multisystemic disease probably caused by the ingestion of denatured rapeseed oil, and in 50 control volunteers. Higher circulating levels of factor VIII procoagulant activity (VIII :C) (158 ± 58.4 U/dl), von Willebrand factor antigen (vWF: Ag) (166.1 ± 55.5 U/dl) and von Willebrand factor ristocetin cofactor activity (vWF:RCo) (178.7 ± 55.2 U/dl) were seen in TES patients (p < 0.001, TES patients versus control subjects, for each parameter). The increased levels of vWF:Ag and vWF:RCo observed in TES patients correlated with the scleroderma like lesion of the skin, with the sicca syndrome and with Raynaud's phenomenon (p < 0.01), but not with other clinical manifestations. The multimeric analysis of vWF in 92% of the TES patients was similar to that found in normal plasma, but in the remaining 8% a very slight increase of larger vWF multimers in plasma were observed. The raised levels of vWF found in TES patients in the chronic phase may reflect an “in vivo” vascular injury.

scholarly journals Rickettsia rickettsii infection of cultured endothelial cells induces release of large von Willebrand factor multimers from Weibel-Palade bodies

Blood ◽  
1991 ◽  
Vol 78 (10) ◽  
pp. 2595-2602 ◽  
Author(s):  
LA Sporn ◽  
RJ Shi ◽  
SO Lawrence ◽  
DJ Silverman ◽  
VJ Marder
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Culture Medium ◽  
Spotted Fever ◽  
Clinical Manifestations ◽  
Tissue Ischemia ◽  
Rickettsia Rickettsii ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The clinical manifestations of Rocky Mountain spotted fever (RMSF) result from Rickettsia rickettsii (R rickettsii) infection of endothelial cells and are mediated by pathologic changes localized to the vessel, including in situ thrombosis and tissue ischemia. This study uses in vitro infection of cultured human umbilical vein endothelial cells with R rickettsii to test the hypothesis that such infection induces von Willebrand factor (vWF) release from Weibel- Palade bodies, a process that could contribute to thrombotic changes. At 24 hours postinfection, there was an increase in metabolically prelabeled large multimers of vWF in the culture medium, with a concomitant decrease of these forms in the cell lysate samples. This release reaction was specific for the large multimer pool of vWF, localized to Weibel-Palade bodies, because no change in the distribution of dimeric forms between cells and culture medium was detected. Double-label immunofluorescence staining showed an inverse correlation between the number of R rickettsii and the number of Weibel- Palade bodies in infected cells. Cell lysis was minimal at 24 hours postinfection, as no detectable intracellular precursor forms (molecular weight 260,000) of vWF were released into the culture medium, there was no decrease in cell viability as measured by trypan blue exclusion, and no increase in 51Cr-release into the culture medium was observed when compared with uninfected controls. Release was likely a direct effect of the intracellular presence of the organism, rather than due to a noxious soluble factor such as endotoxin, because culture medium conditioned by infected endothelial cells was ineffective at inducing release in uninfected endothelial cell cultures. In summary, in vitro infection of endothelial cells by R rickettsii induces release of Weibel-Palade body contents, a process that may contribute to the pathogenesis of RMSF.

scholarly journals von Willebrand factor variant D1472H has no effect in mice with humanized VWF-platelet interactions

2020 ◽  
Vol 4 (17) ◽  
pp. 4065-4068
Author(s):  
Hannah K. Lohmeier ◽  
Tricia L. Slobodianuk ◽  
Sachiko Kanaji ◽  
Sandra L. Haberichter ◽  
Robert R. Montgomery ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sequence Variant ◽  
Wild Type ◽  
Activity Assay ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

Abstract The von Willebrand factor ristocetin cofactor activity assay (VWF:RCo) is used for diagnosis of von Willebrand disease (VWD) because of its ability to evaluate VWF binding to platelets. VWF sequence variant p.D1472H is associated with lower VWF:RCo levels in the absence of associated bleeding symptoms, indicating the VWF:RCo may not be accurate for characterizing VWF function in individuals with this variant. Thus, this study aimed to determine the implications of the variant on VWF functioning in vivo. Mice were engineered with humanized wild-type (WT*) VWF A1/A2 and VWF with the p.D1472H (1472H) variant along with humanized platelet GPIbα and bred to homozygosity. VWF antigen and VWF binding to GPIbα were measured using enzyme-linked immunosorbent assay. Gel electrophoresis was used for VWF multimer analysis. Tail bleeding assays were performed at a 3-mm defined length. Normal VWF multimers were preserved in both WT* and 1472H mice. VWF expression was normal in the WT* and 1472H mice, and VWF binding to GPIbα did not statistically differ between the groups. Additionally, tail bleeding times were similar for WT* and 1472H mice. These results show the p.D1472H variant does not impair hemostasis in mice, and support the conclusion that p.D1472H is a normal variant in humans.

scholarly journals Rickettsia rickettsii infection of cultured endothelial cells induces release of large von Willebrand factor multimers from Weibel-Palade bodies

Blood ◽  
1991 ◽  
Vol 78 (10) ◽  
pp. 2595-2602
Author(s):  
LA Sporn ◽  
RJ Shi ◽  
SO Lawrence ◽  
DJ Silverman ◽  
VJ Marder
Keyword(s):  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Culture Medium ◽  
Spotted Fever ◽  
Clinical Manifestations ◽  
Tissue Ischemia ◽  
Rickettsia Rickettsii ◽  
Von Willebrand ◽  
Willebrand Factor

The clinical manifestations of Rocky Mountain spotted fever (RMSF) result from Rickettsia rickettsii (R rickettsii) infection of endothelial cells and are mediated by pathologic changes localized to the vessel, including in situ thrombosis and tissue ischemia. This study uses in vitro infection of cultured human umbilical vein endothelial cells with R rickettsii to test the hypothesis that such infection induces von Willebrand factor (vWF) release from Weibel- Palade bodies, a process that could contribute to thrombotic changes. At 24 hours postinfection, there was an increase in metabolically prelabeled large multimers of vWF in the culture medium, with a concomitant decrease of these forms in the cell lysate samples. This release reaction was specific for the large multimer pool of vWF, localized to Weibel-Palade bodies, because no change in the distribution of dimeric forms between cells and culture medium was detected. Double-label immunofluorescence staining showed an inverse correlation between the number of R rickettsii and the number of Weibel- Palade bodies in infected cells. Cell lysis was minimal at 24 hours postinfection, as no detectable intracellular precursor forms (molecular weight 260,000) of vWF were released into the culture medium, there was no decrease in cell viability as measured by trypan blue exclusion, and no increase in 51Cr-release into the culture medium was observed when compared with uninfected controls. Release was likely a direct effect of the intracellular presence of the organism, rather than due to a noxious soluble factor such as endotoxin, because culture medium conditioned by infected endothelial cells was ineffective at inducing release in uninfected endothelial cell cultures. In summary, in vitro infection of endothelial cells by R rickettsii induces release of Weibel-Palade body contents, a process that may contribute to the pathogenesis of RMSF.

Demonstration of Rickettsia Conorii-Induced Coagulative and Platelet Activation in vivo in Patients with Mediterranean Spotted Fever

1995 ◽  
Vol 74 (02) ◽  
pp. 631-634 ◽  
Author(s):  
Giovanni Davì ◽  
Carlo Giammarresi ◽  
Sergio Vigneri ◽  
Antonina Ganci ◽  
Claudio Ferri ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Platelet Activation ◽  
Acute Phase ◽  
Thrombin Generation ◽  
Spotted Fever ◽  
Clinical Manifestations ◽  
Etiologic Agent ◽  
Rickettsia Conorii ◽  
Mediterranean Spotted Fever

SummaryEndothelial injury in vivo induced by Rickettsia Conorii, the etiologic agent of Mediterranean Spotted Fever (MSF) has been recently demonstrated. We sought to determine whether platelet and/or coagulative activation in vivo can be demonstrated in the acute phase of MSF, through measurements of a major metabolite of thromboxane (TX) in the urine (1 1-dehydro-TXB2) and of plasma prothrombin fragment 1+2, whose levels reflect activation of prothrombin to thrombin. Moreover, we measured plasma endothelin-1 as marker of endothelial dysfunction. Our results provide biochemical evidence for the occurrence of TXA2-dependent platelet activation and thrombin generation in vivo, together with endothelial dysfunction. These phenomena could account for clinical manifestations of MSF, such as vasculitis and focal microthrombus formation. These results could also provide a rationale for testing the efficacy of aspirin or heparin in reducing the prothrombotic status of Rickettsiae diseases.

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.

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