Measurement and characterization of free radical generation in reoxygenated human endothelial cells

1994 ◽  
Vol 266 (3) ◽  
pp. C700-C708 ◽  
Author(s):  
J. L. Zweier ◽  
P. Kuppusamy ◽  
S. Thompson-Gorman ◽  
D. Klunk ◽  
G. A. Lutty

The endothelial cell is thought to be an important site of free radical generation in ischemic tissues. It has been demonstrated that endothelial cells from several species generate a burst of free radical generation upon reoxygenation; however, it has been suggested that human endothelial cells are not similarly capable of generating free radicals on reoxygenation. In view of the central importance of revascularization with accompanying reoxygenation in the clinical treatment of tissue ischemia/infarction, we have performed studies to determine the presence, mechanism, and kinetics of free radical generation in human endothelial cells. Therefore, we subjected cultured human umbilical vein endothelial cells to anoxia followed by reoxygenation. Cell suspensions of 10(7) cells/ml were subjected to varying periods of anoxia and reoxygenation. On reoxygenation with addition of a 50 mM concentration of the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), after 90 min of anoxia an electron paramagnetic resonance (EPR) signal was observed consisting of 2 components: a quartet 1:2:2:1 DMPO-OH signal, aN = aH = 14.9 G, and a six-peaked DMPO-R signal, aN = 15.6 G aH = 22.9 G, whereas cells in air gave no signal. The observed signal was quenched by superoxide dismutase (SOD) or catalase. Deferoxamine decreased the measured radical signals by 40%. Cyclooxygenase blockers did not decrease radical generation, but the xanthine oxidase blocker oxypurinol did decrease radical generation by 60%.

2002 ◽  
Vol 283 (6) ◽  
pp. H2644-H2649 ◽  
Author(s):  
Carlos Hermenegildo ◽  
Marı́a Cinta Garcı́a-Martı́nez ◽  
Juan J. Tarı́n ◽  
Antonio Cano

Free radical-generated F2α-isoprostanes are a group of compounds with vasoconstrictor properties. To investigate whether estradiol exerts antioxidant actions modifying F2α-isoprostane production, cultured human umbilical vein endothelial cells were exposed to estradiol and other compounds and F2α-isoprostanes were measured in culture medium. Exposure to 1 and 10 nM estradiol for 24 h reduced F2α-isoprostane production by 36 and 49%, respectively ( P < 0.001 vs. control). Exposure to antiestrogens alone (ICI-182780 or EM-652) slightly reduced F2α-isoprostanes ( P < 0.05 vs. control), but much less than exposure to estradiol ( P < 0.05). ICI-182780 reversed the estradiol-induced reduction of F2α-isoprostane concentration ( P < 0.05). Along with time-course analysis, these results suggest that estradiol effects were mediated through estrogen receptor-dependent and -independent mechanisms. Progestogens alone (progesterone or medroxyprogesterone acetate) did not modify F2α-isoprostane production at any of the tested concentrations (1, 10, and 100 nM). Progesterone completely reversed estradiol-induced reduction of F2α-isoprostane production ( P < 0.05 vs. control and estradiol), but medroxyprogesterone acetate did not ( P < 0.05 vs. control).


1989 ◽  
Vol 62 (02) ◽  
pp. 699-703 ◽  
Author(s):  
Rob J Aerts ◽  
Karin Gillis ◽  
Hans Pannekoek

SummaryIt has recently been shown that the fibrinolytic components plasminogen and tissue-type plasminogen activator (t-PA) both bind to cultured human umbilical vein endothelial cells (HUVEC). After cleavage of t-PA by plasmin, “single-chain” t-PA (sct-PA) is converted into “two-chain” t-PA (tct-PA), which differs from the former in a number of respects. We compared binding of sct-PA and tct-PA to the surface of HUVEC. Removal of t-PA bound to HUVEC by a mild treatment with acid and a subsequent quantification of eluted t-PA both by activity- and immunoradiometric assays revealed that, at concentrations between 10 and 500 nM, HUVEC bind about 3-4 times more sct-PA than tct-PA. At these concentrations, both sct-PA and tct-PA remain active when bound to HUVEC. Mutual competition experiments showed that sct-PA and tct-PA can virtually fully inhibit binding of each other to HUVEC, but that an about twofold higher concentration of tct-PA is required to prevent halfmaximal binding of sct-PA than visa versa. These results demonstrate that sct-PA and tct-PA bind with different affinities to the same binding sites on HUVEC.


1995 ◽  
Vol 74 (02) ◽  
pp. 698-703 ◽  
Author(s):  
Catherine Lenich ◽  
Ralph Pannell ◽  
Victor Gurewich

SummaryFactor XII has long been implicated in the intrinsic pathway of fibrinolysis, but the mechanism by which it triggers plasminogen activation and targets fibrinolysis has not been established. In the present study, the assembly and function of activated Factor XII (F.XIIa), prourokinase (pro-u-PA), high molecular weight kininogen (H-kininogen), and prekallikrein on human umbilical vein endothelial cells (HUVEC) was investigated. 125I-prekallikrein was shown to bind to HUVEC via receptor-bound H-kininogen in the presence of 50 μM ZnCl2. After the addition of F.XIIa, 78% of the 125I-prekallikrein initially bound to HUVEC was converted to 125I-kallikrein. However, only 6% of the HUVEC-bound 125I-pro-u-PA was thereby activated. This discrepancy was shown to be related to rapid dissociation (>50% within 15 min) of prekallikrein/kallikrein, but not pro-u-PA, from HUVEC. Increasing the level of cell-bound kallikrein increased the portion of cell-bound pro-u-PA activated, indicating that their co-localization was important for this pathway. Finally, F.XIIa was shown to trigger plasminogen activation on HUVEC via this pathway. This assembly of reactants on the endothelium suggests a mechanism whereby local fibrinolysis may be triggered by blood coagulation.


1982 ◽  
Vol 47 (02) ◽  
pp. 128-131 ◽  
Author(s):  
F Esnard ◽  
E Dupuy ◽  
A M Dosne ◽  
E Bodevin

SummaryA preliminary characterization of a fibrinolytic inhibitor released by human umbilical vein endothelial cells in primary culture is reported. This molecule of Mr comprised between 2 × 105 and 106 and of μ2 mobility precipitates at 43% ammonium sulphate saturation and is totally adsorbed on Concanavalin A Sepharose 4 B. A possible relationship with a macroglobulins is discussed.


1983 ◽  
Vol 49 (02) ◽  
pp. 069-072 ◽  
Author(s):  
U L H Johnsen ◽  
T Lyberg ◽  
K S Galdal ◽  
H Prydz

SummaryHuman umbilical vein endothelial cells in culture synthesize thromboplastin upon stimulation with phytohaemagglutinin (PHA) or the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The thromboplastin activity is further strongly enhanced in a time dependent reaction by the presence of gel-filtered platelets or platelet aggregates. This effect was demonstrable at platelet concentrations lower than those normally found in plasma, it may thus be of pathophysiological relevance. The thromboplastin activity increased with increasing number of platelets added. Cycloheximide inhibited the increase, suggesting that de novo synthesis of the protein component of thromboplastin, apoprotein III, is necessary.When care was taken to remove monocytes no thromboplastin activity and no apoprotein HI antigen could be demonstrated in suspensions of gel-filtered platelets, platelets aggregated with thrombin or homogenized platelets when studied with a coagulation assay and an antibody neutralization technique.


1986 ◽  
Vol 6 (8) ◽  
pp. 3018-3022
Author(s):  
B D Tong ◽  
S E Levine ◽  
M Jaye ◽  
G Ricca ◽  
W Drohan ◽  
...  

A clone containing the 3' end of the mRNA for the human c-sis gene (homologous to the B chain of platelet-derived growth factor) was isolated from a cDNA library derived from human umbilical vein endothelial cells and then sequenced. The analysis of possible translation products in all three reading frames indicated that the A chain of platelet-derived growth factor was not coded for within the 3' end of the c-sis mRNA. The 3' end of the mRNA for c-sis is contained in or adjacent to exon 6.


2004 ◽  
Vol 164 (6) ◽  
pp. 811-817 ◽  
Author(s):  
Carlo Iomini ◽  
Karla Tejada ◽  
Wenjun Mo ◽  
Heikki Vaananen ◽  
Gianni Piperno

We identified primary cilia and centrosomes in cultured human umbilical vein endothelial cells (HUVEC) by antibodies to acetyl-α-tubulin and capillary morphogenesis gene-1 product (CMG-1), a human homologue of the intraflagellar transport (IFT) protein IFT-71 in Chlamydomonas. CMG-1 was present in particles along primary cilia of HUVEC at interphase and around the oldest basal body/centriole at interphase and mitosis. To study the response of primary cilia and centrosomes to mechanical stimuli, we exposed cultured HUVEC to laminar shear stress (LSS). Under LSS, all primary cilia disassembled, and centrosomes were deprived of CMG-1. We conclude that the exposure to LSS ends the IFT in cultured endothelial cells.


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