Thromb Haemost 1998; 80(06): 961-967
DOI: 10.1055/s-0037-1615396
Letters to the Editor
Schattauer GmbH

Evidence for the Expression of Urokinase-type Plasminogen Activator by Human Venous Endothelial Cells In Vivo

L. Camoin
1   Laboratoire d’lmmuno-Hématologie, Faculté de Pharmacie
,
R. Pannell
3   Vascular Research Laboratory, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
,
F. Anfosso
1   Laboratoire d’lmmuno-Hématologie, Faculté de Pharmacie
,
J. P. Lefevre
2   Service d’Hématologie d’Hôpital de la Conception, Marseille, France
,
J. Sampol
1   Laboratoire d’lmmuno-Hématologie, Faculté de Pharmacie
,
V. Gurewich
3   Vascular Research Laboratory, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
,
F. Dignat-George
1   Laboratoire d’lmmuno-Hématologie, Faculté de Pharmacie
› Author Affiliations

Supported by a grant from Ministère de l’Education Nationale, de l’Enseignement Supérieur et de la Recherche, UPRES EA 2195, France, and Neurex Corporation, Menlo Park, CA, USA
Further Information

Publication History

Received 27 April 1998

Accepted after revision 18 August 1998

Publication Date:
07 December 2017 (online)

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Summary

Endothelial cells (ECs) in culture synthesize and secrete urokinase-type plasminogen activator (u-PA), but the normal vascular endothelium is believed to synthesize only tissue plasminogen activator (t-PA), which is thought to be responsible for intravascular fibrinolysis. More recently, animal studies have shown that the biological role of u-PA in fibrinolysis has been underestimated, prompting a re-examination of its synthesis by the endothelium. In this study, we investigated whether u-PA was synthesized by non-atherosclerotic endothelial cells in vivo by testing ECs dislodged by venipuncture from 12 normal volunteers and 17 patients admitted for plasmapheresis. The ECs were isolated with an anti-endothelial monoclonal antibody coupled to immunomagnetic beads and characterized by morphology and by labelling for vWF, CD31, and UEA-1 binding. U-PA antigen was found in 50% of the ECs from the normal subjects and in 60% of those from patients. U-PA enzymatic activity on zymograms was detected in 50% of the normal samples and 60% of the patient samples, with the latter being more frequently and more strongly positive. U-PA mRNA was found in all the normal and patient samples tested. The results indicate that u-PA is synthesized by the venous endothelium in vivo but that its expression is highly variable.