Evidence for the expression of urokinase-type plasminogen activator by human venous endothelial cells in vivo.
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.
Camoin
L
L
Laboratoire d'Immuno-Hématologie, Faculté de Pharmacie, Hôpital de la Conception, Marseille, France.
Pannell
R
R
Anfosso
F
F
Lefevre
J P
JP
Sampol
J
J
Gurewich
V
V
Dignat-George
F
F
D000328:Adult; D015415:Biomarkers; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology*; D004790:Enzyme Induction; D005260:Female; D005342:Fibrinolysis; D006801:Humans; D018189:Immunomagnetic Separation; D017403:In Situ Hybridization; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D014568:Urokinase-Type Plasminogen Activator / Q000096:biosynthesis* / Q000235:genetics; D014680:Veins
D015415:Biomarkers; D012333:RNA, Messenger; D014568:Urokinase-Type Plasminogen Activator