scholarly journals Procoagulant activity of endotoxin-treated human endothelial cells exposed to native human flowing blood

Blood ◽  
1989 ◽  
Vol 73 (3) ◽  
pp. 729-733
Author(s):  
M Clozel ◽  
H Kuhn ◽  
HR Baumgartner

It has been reported that cultured endothelial cells become procoagulant when exposed to endotoxin. This prompted us to investigate whether human endothelial cells treated with endotoxin could promote the generation of fibrin when exposed to human flowing blood. For this purpose we used a parallel-plate perfusion chamber in which confluent cultured endothelial cells from human umbilical veins were exposed for five minutes to directly drawn human nonanticoagulated blood, at wall shear rates of 100, 650, and 2600 sec-1. Fibrin deposition was assessed by morphometry. No fibrin deposition occurred on normal endothelial cells. In contrast, cells incubated with endotoxin for 4 or 18 hours induced fibrin deposition, but only at a shear rate of 100 sec-1. Since some extracellular matrix was exposed between the cells, we investigated whether extracellular matrix played a role in fibrin formation. When the endothelial cells incubated or not with endotoxin were removed by EDTA, the exposed extracellular matrix perfused with blood at 100 sec-1 supported platelet and fibrin deposition in both cases. This suggests that the effect of endotoxin on endothelial cells was not due to extracellular matrix alteration but only to cellular activation or secretion of procoagulant substances. We conclude that human endothelial cells treated with endotoxin can trigger fibrin formation and deposition at their surface when exposed to flowing blood at low shear rate.

Blood ◽  
1989 ◽  
Vol 73 (3) ◽  
pp. 729-733 ◽  
Author(s):  
M Clozel ◽  
H Kuhn ◽  
HR Baumgartner

Abstract It has been reported that cultured endothelial cells become procoagulant when exposed to endotoxin. This prompted us to investigate whether human endothelial cells treated with endotoxin could promote the generation of fibrin when exposed to human flowing blood. For this purpose we used a parallel-plate perfusion chamber in which confluent cultured endothelial cells from human umbilical veins were exposed for five minutes to directly drawn human nonanticoagulated blood, at wall shear rates of 100, 650, and 2600 sec-1. Fibrin deposition was assessed by morphometry. No fibrin deposition occurred on normal endothelial cells. In contrast, cells incubated with endotoxin for 4 or 18 hours induced fibrin deposition, but only at a shear rate of 100 sec-1. Since some extracellular matrix was exposed between the cells, we investigated whether extracellular matrix played a role in fibrin formation. When the endothelial cells incubated or not with endotoxin were removed by EDTA, the exposed extracellular matrix perfused with blood at 100 sec-1 supported platelet and fibrin deposition in both cases. This suggests that the effect of endotoxin on endothelial cells was not due to extracellular matrix alteration but only to cellular activation or secretion of procoagulant substances. We conclude that human endothelial cells treated with endotoxin can trigger fibrin formation and deposition at their surface when exposed to flowing blood at low shear rate.


Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2206-2213 ◽  
Author(s):  
A Diquelou ◽  
S Lemozy ◽  
D Dupouy ◽  
B Boneu ◽  
K Sakariassen ◽  
...  

We have investigated the influence of blood flow on thrombin generation, fibrin formation, and fibrin deposition on procoagulant and nonprocoagulant surfaces. Nonanticoagulated human blood was drawn for 5 minutes directly from an antecubital vein over stimulated endothelial cells expressing tissue factor and over human type III collagen fibrils, positioned in parallel-plate perfusion chambers. The shear rates at these surfaces were 50, 650, and 2,600 s-1. Deposition of platelets and fibrin was measured by morphometry. Thrombin and fibrin formation was determined by measuring prothrombin fragments 1 + 2 (F 1 + 2), thrombin-antithrombin III complexes, (T-AT) and fibrinopeptide A (FPA) in blood effluent from the perfusion chamber at the end of the 5- minute perfusion period. On procoagulant endothelial cells, the thrombi were primarily composed of fibrin. The fibrin deposition (81%, 21%, and 2% at 50, 650, and 2,600 s-1, respectively) and plasma levels of F 1 + 2, T-AT and FPA were shear rate dependent and highest at 50 s-1. There was a positive correlation between F 1 + 2 and T-AT and the fibrin deposition (P < .01). In contrast, the collagen surface triggered primarily thrombi that were composed of platelets. The platelet thrombi and plasma levels of F 1 + 2 and T-AT were also dependent on the shear rate, but highest at 650 and 2,600 s-1. F 1 + 2 and T-AT reached the same level as observed with procoagulant endothelial cells at the higher shear rates. There was a positive correlation between F 1 + 2 and T-AT and the platelet thrombus formation (P < .05), confirming the predominant role of platelets in thrombin generation. Thus, thrombin formation is strongly influenced by the blood flow, and this effect depends on the composition of the thrombogenic surface.


Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2206-2213 ◽  
Author(s):  
A Diquelou ◽  
S Lemozy ◽  
D Dupouy ◽  
B Boneu ◽  
K Sakariassen ◽  
...  

Abstract We have investigated the influence of blood flow on thrombin generation, fibrin formation, and fibrin deposition on procoagulant and nonprocoagulant surfaces. Nonanticoagulated human blood was drawn for 5 minutes directly from an antecubital vein over stimulated endothelial cells expressing tissue factor and over human type III collagen fibrils, positioned in parallel-plate perfusion chambers. The shear rates at these surfaces were 50, 650, and 2,600 s-1. Deposition of platelets and fibrin was measured by morphometry. Thrombin and fibrin formation was determined by measuring prothrombin fragments 1 + 2 (F 1 + 2), thrombin-antithrombin III complexes, (T-AT) and fibrinopeptide A (FPA) in blood effluent from the perfusion chamber at the end of the 5- minute perfusion period. On procoagulant endothelial cells, the thrombi were primarily composed of fibrin. The fibrin deposition (81%, 21%, and 2% at 50, 650, and 2,600 s-1, respectively) and plasma levels of F 1 + 2, T-AT and FPA were shear rate dependent and highest at 50 s-1. There was a positive correlation between F 1 + 2 and T-AT and the fibrin deposition (P < .01). In contrast, the collagen surface triggered primarily thrombi that were composed of platelets. The platelet thrombi and plasma levels of F 1 + 2 and T-AT were also dependent on the shear rate, but highest at 650 and 2,600 s-1. F 1 + 2 and T-AT reached the same level as observed with procoagulant endothelial cells at the higher shear rates. There was a positive correlation between F 1 + 2 and T-AT and the platelet thrombus formation (P < .05), confirming the predominant role of platelets in thrombin generation. Thus, thrombin formation is strongly influenced by the blood flow, and this effect depends on the composition of the thrombogenic surface.


1978 ◽  
Vol 147 (6) ◽  
pp. 1779-1791 ◽  
Author(s):  
E A Jaffe ◽  
D F Mosher

Plasma fibronectin is probably the major nonimmune particulate opsonin in blood and is cross-linked to fibrin during the final stage of blood coagulation. Fibronectin also occurs in an insoluble form in basement membranes especially those underlying endothelial cells and in loose connective tissue. Fibronectin was demonstrated in cultured human endothelial cells and in the surrounding extracellular matrix by immunofluorescence microscopy by using antibody to human plasma fibronectin. Cultured human endothelial cells released fibronectin into the culture medium which was immunologically identical to the fibronectin in human plasma. Cultured human endothelial cells were labeled with [3H] leucine. The radioactive fibronectin present in the endothelial postculture medium and in urea extracts of cellular monolayers was isolated with either anti-fibronectin coupled to Protein A-Sepharose or double antibody immunoprecipitation and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When reduced, the [3H] fibronectin synthesized by cultured endothelial cells had the same mol wt (approximately 200,000) as plasma fibronectin. Unreduced, the [3H] fibronectin synthesized by endothelial cells migrated as a dimer, as did plasma fibronectin. Fibronectin accounted for approximately 15% of the protein synthesized and released by endothelial cells into the culture medium. Thus, cultured endothelial cells synthesize fibronectin, secrete it into the culture medium, and incorporate it into extracellular matrix. The results suggest that the endothelial cell is potentially a major site of synthesis of circulating plasma fibronectin. In addition, fibronectin derived from endothelial cells may be an important structural component of the subendothelium.


2002 ◽  
Vol 88 (10) ◽  
pp. 678-685 ◽  
Author(s):  
Berta Fusté ◽  
Mireia Serradell ◽  
Ginés Escolar ◽  
Aleix Cases ◽  
Roberto Mazzara ◽  
...  

SummaryWe demonstrate that exposure of cultured human endothelial cells to rHuEPO resulted in a dose-dependent increase in the tyrosine kinase activity, with phosphorylation of JAK-2 followed by rapid phosphorylation of STAT-5. Simultaneously, rHuEPO induced long-lasting phosphorylation of MAPK p42/44. Activation of this signaling pathways was directly associated with an increase in the thrombogenic properties of the extracellular matrix generated by these cells, when they were exposed to flowing blood. The enhancement in the reactivity of the resulting extracellular matrix towards platelets was associated with a higher expression of tissue factor. All these effects were blocked by an antibody to the EPO receptor and by specific inhibitors of tyrosine phosphorylation. The observed action of rHuEPO on endothelial cells seemed to be specifically triggered by the subsequent events that follow receptor binding, and occurred even at pharmacological concentrations of the cytokine. Our results indicate that rHuEPO has a direct action on the endothelium, increasing the reactivity of the underlying extracellular matrix towards platelets, effect that may be attributed to an increase in the expression of TF.


Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1531-1534 ◽  
Author(s):  
LA Sporn ◽  
VJ Marder ◽  
DD Wagner

Abstract Large multimers of von Willebrand factor (vWf) are released from the Weibel-Palade bodies of cultured endothelial cells following treatment with a secretagogue (Sporn et al, Cell 46:185, 1986). These multimers were shown by immunofluorescent staining to bind more extensively to the extracellular matrix of human foreskin fibroblasts than constitutively secreted vWf, which is composed predominantly of dimeric molecules. Increased binding of A23187-released vWf was not due to another component present in the releasate, since releasate from which vWf was adsorbed, when added together with constitutively secreted vWf, did not promote binding. When iodinated plasma vWf was overlaid onto the fibroblasts, the large forms bound preferentially to the matrix. These results indicated that the enhanced binding of the vWf released from the Weibel-Palade bodies was likely due to its large multimeric size. It appears that multivalency is an important component of vWf interaction with the extracellular matrix, just as has been shown for vWf interaction with platelets. The pool of vWf contained within the Weibel-Palade bodies, therefore, is not only especially suited for platelet binding, but also for interaction with the extracellular matrix.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maarten M. Brandt ◽  
Christian G. M. van Dijk ◽  
Ranganath Maringanti ◽  
Ihsan Chrifi ◽  
Rafael Kramann ◽  
...  

Abstract Microvascular homeostasis is strictly regulated, requiring close interaction between endothelial cells and pericytes. Here, we aimed to improve our understanding of how microvascular crosstalk affects pericytes. Human-derived pericytes, cultured in absence, or presence of human endothelial cells, were studied by RNA sequencing. Compared with mono-cultured pericytes, a total of 6704 genes were differentially expressed in co-cultured pericytes. Direct endothelial contact induced transcriptome profiles associated with pericyte maturation, suppression of extracellular matrix production, proliferation, and morphological adaptation. In vitro studies confirmed enhanced pericyte proliferation mediated by endothelial-derived PDGFB and pericyte-derived HB-EGF and FGF2. Endothelial-induced PLXNA2 and ACTR3 upregulation also triggered pericyte morphological adaptation. Pathway analysis predicted a key role for TGFβ signaling in endothelial-induced pericyte differentiation, whereas the effect of signaling via gap- and adherens junctions was limited. We demonstrate that endothelial cells have a major impact on the transcriptional profile of pericytes, regulating endothelial-induced maturation, proliferation, and suppression of ECM production.


1995 ◽  
Vol 108 (2) ◽  
pp. 797-809 ◽  
Author(s):  
A.E. Canfield ◽  
A.M. Schor

Cultured endothelial cells undergo a reversible transition from a resting (cobblestone) phenotype to an angiogenic (sprouting) phenotype. This transition mimics the early events of angiogenesis. We have previously reported that the addition of exogenous xylosides inhibits endothelial cel sprouting and modifies the extracellular matrix (ECM) synthesised by the cells. We have now investigated whether endothelial sprouting is mediated by the nature of the extracellular matrix in contact with the cells. Accordingly, cell-free matrices deposited by bovine aortic endothelial cells (BAEC) were isolated. These matrices were produced under conditions in which the formation of the sprouting phenotype was permitted (controls) or inhibited (by the addition of exogenous xylosides). BAEC were then plated on these matrices and grown under conditions which promote sprouting. Sprouting proceeded normally on control matrices, whereas it was inhibited when the cells were grown on matrices deposited in the presence of xylosides. The composition of the permissive and inhibitory matrices was then analysed. Inhibitory matrices contained reduced levels of tenascin and increased levels of thrombospondin-1 by comparison to the permissive matrices. In contrast, no differences were detected in the relative levels of laminin. The roles of tenascin and thrombospondin-1 in endothelial sprouting were confirmed using specific antibodies. Immunolocalisation studies revealed the presence of both proteins in sprouting cells. Antibodies to tenascin inhibited the formation of sprouting cells on permissive matrices and on gelatin-coated dishes without affecting cell growth. Tenascin synthesis was increased when sprouting cells were present in the cultures. Antibodies to thrombospondin-1 stimulated sprouting on inhibitory matrices. These results suggest that the transition from a resting to a sprouting phenotype is promoted by tenascin and inhibited by thrombospondin-1.


1991 ◽  
Vol 65 (05) ◽  
pp. 596-600 ◽  
Author(s):  
Kjell S Sakariassen ◽  
Harvey J Weiss ◽  
Hans R Baumgartner

SummaryIn the present experiments we have investigated the influence of wall shear rate and axial position on platelet and fibrin deposition which results when flowing human non-anticoagulated blood is exposed to either non-procoagulant fibrillar collagen (human type III) or procoagulant subendothelium (rabbit aorta). Platelet adhesion, thrombus volume and fibrin deposition were morphometrically evaluated at axial positions of 1 and 13 mm following perfusions for 5 min at shear rates of 100, 650 and 2,600 s-1.An axially-dependent decrease of platelet adhesion (34-57%, p <0.01-0.05) and thrombus volume (57-80%, p <0.05) was observed on collagen at all shear rates. On subendothelium, an axially-dependent decrease was observed for platelet adhesion only at 100 s-1 (29% ; p <0.01) and for thrombus volume at shear rates of 650 s-1 and above (49-58%, p <0.01). Deposition of fibrin on subendothelium was axially decreased (16-42%, p <0.05) at all shear rates, while no significant axial differences were seen on collagen. However, substantially more fibrin was deposited on the subendothelium (p <0.05), and the upstream platelet adhesion and thrombus volume were lower than on collagen (p <0.05) at 100 s-1 and 650 s-1. The axially-dependent phenomena on the two surfaces are consistent with the concept of rapid-growing upstream thrombi which deplete the blood layer streaming adjacent to the surface of platelets, leading to decreased platelet deposition farther downstream. The observations suggest that deposition of fibrin is enhanced by subendothelial tissue factor, and that upstream depletion of clotting factors may lower the downstream deposition of fibrin, analogous to the depletion of platelets.


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