Title
Tumor necrosis factor increases the production of plasminogen activator inhibitor in human endothelial cells in vitro and in rats in vivo
Author
van Hinsbergh, V.W.M.
Kooistra, T.
van den Berg, E.A.
Princen, H.M.G.
Fiers, W.
Emeis, J.J.
Gaubius instituut TNO
Publication year
1988
Abstract
The vascular endothelium plays an important role in fibrinolysis by producing tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI). The monokine tumor necrosis factor (human recombinant TNF) increased the production of PAI by cultured human endothelial cells from umbilical vein (twofold) and from foreskin microvessels (four to eight fold). This was demonstrated by titration of endothelial cell-conditioned medium with t-PA, by reverse fibrin autography, and by immunoprecipitation of [35S]PAI-1 by anti-PAI-1 IgG. TNF also induced a marked increase in PAI-1 messenger RNA (mRNA) in the cells. The stimulation of PAI activity by TNF was seen at 4 U/mL and reached a maximum at 500 U/mL. Human recombinant lymphotoxin and interleukin-1 (α and β) also stimulated the production of PAI activity, while interleukin-6 was ineffective. Separate additions of TNF or interleukin-1 (IL-1) at optimal concentrations (500 U/mL and 5 U/mL, respectively) resulted in a comparable stimulation of PAI production by endothelial cells. The simultaneous addition of both mediators resulted in an additive effect. The effect of TNF could not be prevented by the addition of polymyxin B or by anti-IL-1 antibodies. Therefore, it is unlikely that TNF acts through the induction of IL-1 secretion by endothelial cells. Two hours after a bolus injection of 250,000 U/kg TNF into rats, a fivefold increase in circulating PAI levels was found. In the next ten hours, the levels returned to normal. Blood platelets do not significantly contribute to the increase in circulating PAI, because the number of platelets did not change after TNF injection and the amount of PAI in blood platelets is not sufficient for several hours during an increase in PAI activity. The acute phase reactants, fibrinogen and α2-antiplasmin in rat plasma, were altered little if any two to 24 hours after injection of 250,000 U/kg TNF. In vitro, TNF did not change PAI production by human and rat hepatocytes in primary monolayer culture. Therefore, it is most likely that vascular endothelial cells contribute to the increased amount of circulating PAI induced by TNF in vivo. This increase in PAI activity might decrease fibrinolysis. Chemicals/CAS: plasminogen activator inhibitor, 105844-41-5; Glycoproteins; Lymphotoxin; Plasminogen Inactivators; RNA, Messenger; Tissue Plasminogen Activator, EC 3.4.21.68; Tumor Necrosis Factor
Subject
Interleukin 1
Interleukin 6
Lymphotoxin
Plasminogen activator inhibitor
Radioisotope
Tumor necrosis factor
Animal experiment
Animal model
Cell culture
Endothelium cell
Human
Human cell
Intravenous drug administration
Liver cell
Nonhuman
Animal
Blotting, Northern
Cells, Cultured
Endothelium, Vascular
Gene Expression Regulation
Glycoproteins
In Vitro
Lymphotoxin
Male
Plasminogen Inactivators
Rats
Rats, Inbred Strains
RNA, Messenger
Support, Non-U.S. Gov't
Tissue Plasminogen Activator
Tumor Necrosis Factor
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TNO identifier
230519
ISSN
0006-4971
Source
Blood, 72 (5), 1467-1473
Document type
article