In Situ von Willebrand Factor Staining in Human Arteries and Veins

The role of divalent cations in platelet adherence to deendothelialized human arteries in flowing blood was investigated in an annular perfusion chamber. Spreading of platelets on the subendothelium was impaired below 30 microM of free Ca2+ ions (Ca2+). When Ca2+ was replaced by Mg2+, adherence was unchanged in perfusates without exogenous factor VIII-von Willebrand factor (FVIII-vWF), but the ability of FVIII-vWF to support platelet adherence was lost. Binding of FVIII-vWF to the vessel wall was independent of divalent cations, but bound FVIII-vWF was only able to mediate adherence after exposure to Ca2+. Pretreatment of FVIII-vWF with the calcium chelator EGTA (10 mM) resulted in loss of the ability to facilitate platelet adherence, while the ristocetin cofactor activity remained intact. Full restoration of the ability to mediate platelet adherence could only be obtained by prolonged dialysis against Ca2+ in the millimolar range. These data indicate that divalent cations have at least two separate roles to play in supporting platelet adherence: (1) platelet spreading on the subendothelium requires Ca2+ or Mg2+; (2) FVIII-vWF should be exposed to Ca2+ to obtain its optimal biologic activity in supporting platelet adherence.

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Von Willebrand Factor in Cultured Human Vascular Endothelial Cells from Adult and Umbilical Cord Arteries and Veins

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661637 ◽

1986 ◽

Vol 56 (02) ◽

pp. 189-192 ◽

Cited By ~ 26

Author(s):

Pauline B van Wachem ◽

Jan Hendrik Reinders ◽

Marijke F van Buul-Wortelboer ◽

Philip G de Groot ◽

Willem G van Aken ◽

...

Keyword(s):

Endothelial Cells ◽

Von Willebrand Factor ◽

Vascular Endothelial Cells ◽

Umbilical Vein ◽

Vena Cava ◽

Ionophore A23187 ◽

Cultured Endothelial Cells ◽

Von Willebrand ◽

Willebrand Factor ◽

Arteries And Veins

SummaryEndothelial cells were cultured from various human arteries and veins, obtained from adult individuals and from umbilical cords. We compared the storage and secretion of von Willebrand factor by endothelial cells from umbilical veins with that of endothelial cells cultured from a number of adult vessels, including aorta, arteria iliaca, vena saphena magna and vena cava. There were no differences in the way the cultured endothelial cells handled the von Willebrand factor they synthesized. Endothelial cells from the various vessels responded to stimuli in secreting stored von Willebrand factor. The cells also responded to thrombin and ionophore A23187 in producing enhanced amounts of prostacyclin. Thus, cultured umbilical vein endothelial cells have properties that are very similar to those of cultured endothelial cells of various other origins. It is concluded that foetal venous cells provide a representative model for studies of endothelial cell von Willebrand factor biosynthesis and prostacyclin production.

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Sublocalization of von Willebrand factor pseudogene to 22q11.22?q11.23 by in situ hybridization in a 46,X,t(X;22)(pter;q11.21) translocation

Human Genetics ◽

10.1007/bf00285168 ◽

1989 ◽

Vol 83 (3) ◽

pp. 264-266 ◽

Cited By ~ 25

Author(s):

P. Patracchini ◽

E. Calzolari ◽

V. Aiello ◽

P. Palazzi ◽

P. Banin ◽

...

Keyword(s):

In Situ Hybridization ◽

Von Willebrand Factor ◽

Von Willebrand ◽

Willebrand Factor

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Factor VIII-von Willebrand factor requires calcium for facilitation of platelet adherence

Blood ◽

10.1182/blood.v63.5.996.996 ◽

1984 ◽

Vol 63 (5) ◽

pp. 996-103 ◽

Cited By ~ 48

Author(s):

KS Sakariassen ◽

M Ottenhof-Rovers ◽

JJ Sixma

Keyword(s):

Factor Viii ◽

Von Willebrand Factor ◽

Divalent Cations ◽

Platelet Adherence ◽

Human Arteries ◽

Platelet Spreading ◽

Von Willebrand ◽

Willebrand Factor ◽

Ristocetin Cofactor

Abstract The role of divalent cations in platelet adherence to deendothelialized human arteries in flowing blood was investigated in an annular perfusion chamber. Spreading of platelets on the subendothelium was impaired below 30 microM of free Ca2+ ions (Ca2+). When Ca2+ was replaced by Mg2+, adherence was unchanged in perfusates without exogenous factor VIII-von Willebrand factor (FVIII-vWF), but the ability of FVIII-vWF to support platelet adherence was lost. Binding of FVIII-vWF to the vessel wall was independent of divalent cations, but bound FVIII-vWF was only able to mediate adherence after exposure to Ca2+. Pretreatment of FVIII-vWF with the calcium chelator EGTA (10 mM) resulted in loss of the ability to facilitate platelet adherence, while the ristocetin cofactor activity remained intact. Full restoration of the ability to mediate platelet adherence could only be obtained by prolonged dialysis against Ca2+ in the millimolar range. These data indicate that divalent cations have at least two separate roles to play in supporting platelet adherence: (1) platelet spreading on the subendothelium requires Ca2+ or Mg2+; (2) FVIII-vWF should be exposed to Ca2+ to obtain its optimal biologic activity in supporting platelet adherence.

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