The Suppression of the Coagulation of Nonanticoagulated Whole Blood in vitro by Human Umbilical Endothelial Cells Cultivated on Microcarriers is not Dependent on Protein C Activation

1995 ◽  
Vol 73 (04) ◽  
pp. 719-724 ◽  
Author(s):  
Hans-Peter Kohler ◽  
Michele Müller ◽  
Thomas Bombeli ◽  
P Werner Straub ◽  
André Haeberli
Keyword(s):  
Endothelial Cells ◽  
Whole Blood ◽  
Protein C ◽  
Umbilical Vein ◽  
Activated Protein C ◽  
Volume Ratio ◽  
Endothelial Cell Surface ◽  
Direct Measurements ◽  
Umbilical Vein Endothelial Cells

SummaryHuman umbilical vein endothelial cells (HUVEC) were cultivated on globular microcarriers in order to improve the endothelial cell surface to blood-volume ratio over the conventional flat bed cultures. HUVEC-beads were tested for their modulation of blood coagulation using a combination of two steps: HUVEC-beads were added into the syringe used for the venipuncture, in order to achieve immediate contact between cells and blood, and no anticoagulant was used during the incubation time of HUVEC-beads with whole blood. The coagulation initiation produced by venipuncture was almost completely suppressed as judged by thrombin measurements over a period of 60 min. The activated partial thromboplastin time showed a prolongation by a factor >3. Direct measurements of activated protein C (APC) were negative. Moreover, inhibition of APC-generation with a monoclonal anti-human protein C antibody did not affect the anticoagulant properties of endothelial cells. Therefore the anticoagulant properties exerted by HUVEC-beads are not dependent on APC.

Platelet factor 4 enhances generation of activated protein C in vitro and in vivo

Blood ◽  
2003 ◽  
Vol 102 (1) ◽  
pp. 146-151 ◽  
Author(s):  
Arne Slungaard ◽  
Jose A. Fernandez ◽  
John H. Griffin ◽  
Nigel S. Key ◽  
Janel R. Long ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Protein C ◽  
Umbilical Vein ◽  
Activated Protein C ◽  
Platelet Factor 4 ◽  
In Vivo Model ◽  
Platelet Factor ◽  
Umbilical Vein Endothelial Cells

Abstract Platelet factor 4 (PF4), an abundant platelet α-granule protein, accelerates in vitro generation of activated protein C (APC) by soluble thrombin/thrombomodulin (TM) complexes up to 25-fold. To test the hypothesis that PF4 similarly stimulates endothelium-associated TM, we assessed the influence of human PF4 on thrombin-dependent APC generation by cultured endothelial monolayers. APC generated in the presence of 1 to 100 μg PF4 was up to 5-fold higher than baseline for human umbilical vein endothelial cells, 10-fold higher for microvascular endothelial cells, and unaltered for blood outgrowth endothelial cells. In an in vivo model, cynomolgus monkeys (n = 6, each serving as its own control) were infused with either PF4 (7.5 mg/kg) or vehicle buffer, then with human thrombin (1.0 μg/kg/min) for 10 minutes. Circulating APC levels (baseline 3 ng/mL) peaked at 10 minutes, when PF4-treated and vehicle-treated animals had APC levels of 67 ± 5 ng/mL and 39 ± 2 ng/mL, respectively (P < .001). The activated partial thromboplastin time (APTT; baseline, 28 seconds) increased maximally by 27 ± 6 seconds in PF4-treated animals and by 9 ± 1 seconds in control animals at 30 minutes (P < .001). PF4-dependent increases in circulating APC and APTT persisted more than 2-fold greater than that of control's from 10 through 120 minutes (P ≤ .04). All APTT prolongations were essentially reversed by monoclonal antibody C3, which blocks APC activity. Thus, physiologically relevant concentrations of PF4 stimulate thrombin-dependent APC generation both in vitro by cultured endothelial cells and in vivo in a primate thrombin infusion model. These findings suggest that PF4 may play a previously unsuspected physiologic role in enhancing APC generation. (Blood. 2003;102:146-151)

Activated protein C induces the release of microparticle-associated endothelial protein C receptor

Blood ◽  
2005 ◽  
Vol 105 (4) ◽  
pp. 1515-1522 ◽  
Author(s):  
Margarita Pérez-Casal ◽  
Colin Downey ◽  
Kenji Fukudome ◽  
Gernot Marx ◽  
Cheng Hock Toh
Keyword(s):  
Endothelial Cells ◽  
Protein C ◽  
Umbilical Vein ◽  
Activated Protein C ◽  
Enzyme Linked Immunosorbent Assay ◽  
Factor V ◽  
Endothelial Protein C Receptor ◽  
Microparticle Formation ◽  
Umbilical Vein Endothelial Cells

Abstract Activated protein C (APC) treatment is now used for patients with severe sepsis. We investigated its effect in vitro on primary, physiologically relevant cells and demonstrate a novel mechanism of endothelial protein C receptor (EPCR) release that is not inhibited by metalloproteinase inhibitors. Exposure of human umbilical vein endothelial cells or monocytes to APC (6.25-100 nM) results in the release of EPCR-containing microparticles, as demonstrated by confocal microscopy and characterized through flow cytometry, enzyme-linked immunosorbent assay quantitation of isolated microparticles, and Western blotting. The phenomenon is time- and concentration-dependent and requires the APC active site, EPCR, and protease activated receptor 1 (PAR1) on endothelial cells. Neither protein C nor boiled or d-Phe-Pro-Arg-chloromethylketone–blocked APC can induce microparticle formation and antibody blockade of EPCR or PAR1 cleavage and activation abrogates this APC action. Coincubation with hirudin does not alter the APC effect. The released microparticle bound is full-length EPCR (49 kDa) and APC retains factor V–inactivating activity. Although tumor necrosis factor-α (10 ng/mL) can also induce microparticle-associated EPCR release to a similar extent as APC (100 nM), it is only APC-induced microparticles that contain bound APC. This novel observation could provide new insights into the consequences of APC therapy in the septic patient.

scholarly journals In Vitro Degradation of Endothelial Catenins by a Neutrophil Protease

1998 ◽  
Vol 140 (2) ◽  
pp. 403-407 ◽  
Author(s):  
Thomas Moll ◽  
Elisabetta Dejana ◽  
Dietmar Vestweber
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Total Cell ◽  
Polymorphonuclear Cells ◽  
Vascular Endothelial ◽  
In Vitro Degradation ◽  
Endothelial Cell Surface ◽  
Vascular Endothelial Cadherin ◽  
Umbilical Vein Endothelial Cells

It has been recently proposed that adhesion of polymorphonuclear cells (PMNs) to human umbilical vein endothelial cells leads to the disorganization of the vascular endothelial cadherin–dependent endothelial adherens junctions. Combined immunofluorescence and biochemical data suggested that after adhesion of PMNs to the endothelial cell surface, β-catenin, as well as plakoglobin was lost from the cadherin/catenin complex and from total cell lysates. In this study we present data that strongly suggest that the adhesion-dependent disappearance of endothelial catenins is not mediated by a leukocyte to endothelium signaling event, but is due to the activity of a neutrophil protease that is released upon detergent lysis of the cells.

Covalent antithrombin-heparin effect on thrombin-thrombomodulin and activated protein C reaction with factor V/Va

2010 ◽  
Vol 103 (05) ◽  
pp. 910-919 ◽  
Author(s):  
Maria Christina Van Walderveen ◽  
Leslie Roy Berry ◽  
Helen Mary Atkinson ◽  
Anthony Kam Chuen Chan
Keyword(s):  
Endothelial Cells ◽  
Chondroitin Sulfate ◽  
Protein C ◽  
Umbilical Vein ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Protein S ◽  
Factor V ◽  
Western Blots ◽  
Umbilical Vein Endothelial Cells

SummaryThrombomodulin (TM), which variably contains a chondroitin sulfate (±CS), forms an anticoagulant complex with thrombin (IIa). IIaTM(±CS) converts protein C (PC) into activated PC (APC), which then inactivates activated factors V (FVa) and VIII (FVIIIa). This reduces prothrombinase and tenase complexes that generate IIa. Heparin (H) increases the rate of IIa-TM inhibition by antithrombin (AT) and enhances FV cleavage by APC. Our novel covalent AT-H (ATH) product, has superior anticoagulant activity compared to AT + unfractionated H (UFH). We studied mechanisms by which ATH versus AT + UFH inhibits IIaTM(±CS), and ATH influences on APC cleavage of FV/FVa compared to UFH. Findings would determine how these reactions moderate ATH’s overall effects as an anticoagulant. Discontinuous second order rate inhibition assays of IIa-TM(±CS) inhibition by AT + UFH or ATH were performed in presence or absence of human umbilical vein endothelial cells (HUVECs). FV/FVa cleavage by APC in the presence of UFH or ATH was analysed by Western blots. ATH increased IIa-TM(±CS) inhibition to a greater degree than AT + UFH, both on plastic and HUVEC surfaces. Unlike UFH, ATH did not accelerate FV cleavage by APC, but ATH did enhance FVa cleavage relative to UFH. Increased IIa-TM inhibition by ATH downregulates PC activation. However, ATH does accelerate downstream inactivation of FVa, which increases its potency for IIa generation inhibition compared to UFH. This trend holds true in the presence of APC’s cofactor, protein S. Overall, ATH may have a balanced function towards inhibiting or accelerating PC pathway activities.

High Affinity Binding Sites for Activated Protein C and Protein C on Cultured Human Umbilical Vein Endothelial Cells

1994 ◽  
Vol 72 (03) ◽  
pp. 465-474 ◽  
Author(s):  
Neelesh Bangalore ◽  
William N Drohan ◽  
Carolyn L Orthner
Keyword(s):  
Binding Sites ◽  
Protein C ◽  
Umbilical Vein ◽  
Activated Protein C ◽  
Affinity Binding ◽  
Cell Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
Gla Domain ◽  
Umbilical Vein Endothelial Cells

SummaryActivated protein C (APC) is an antithrombotic serine proteinase having anticoagulant, profibrinolytic and anti-inflammatory activities. Despite its potential clinical utility, relatively little is known about its clearance mechanisms. In the present study we have characterized the interaction of APC and its active site blocked forms with human umbilical vein endothelial cells (HUVEC). At 4° C 125I-APC bound to HUVEC in a specific, time dependent, saturable and reversible manner. Scatchard analysis of the binding isotherm demonstrated a Kd value of 6.8 nM and total number of binding sites per cell of 359,000. Similar binding isotherms were obtained using radiolabeled protein C (PC) zymogen as well as D-phe-pro-arg-chloromethylketone (PPACK) inhibited APC indicating that a functional active site was not required. Competition studies showed that the binding of APC, PPACK-APC and PC were mutually exclusive suggesting that they bound to the same site(s). Proteolytic removal of the N-terminal γ-carboxyglutamic acid (gla) domain of PC abolished its ability to compete indicating that the gla-domain was essential for cell binding. Surprisingly, APC binding to these cells appeared to be independent of protein S, a cofactor of APC generally thought to be required for its high affinity binding to cell surfaces. The identity of the cell binding site(s), for the most part, appeared to be distinct from other known APC ligands which are associated with cell membranes or extracellular matrix including phospholipid, thrombomodulin, factor V, plasminogen activator inhibitor type 1 (PAI-1) and heparin. Pretreatment of HUVEC with antifactor VIII antibody caused partial inhibition of 125I-APC binding indicating that factor VIII or a homolog accounted for ∼30% of APC binding. Studies of the properties of surface bound 125I-APC or 125I-PC and their fate at 4°C compared to 37 °C were consistent with association of ∼25% of the initially bound radioligand with an endocytic receptor. However, most of the radioligand appeared not to be bound to an endocytic receptor and dissociated rapidly at 37° C in an intact and functional state. These data indicate the presence of specific, high affinity binding sites for APC and PC on the surface of HUVEC. While a minor proportion of binding sites may be involved in endocytosis, the identity and function of the major proportion is presently unknown. It is speculated that this putative receptor may be a further mechanisms of localizing the PC antithrombotic system to the vascular endothelium.

scholarly journals Generation of a Novel In Vitro Model to Study Endothelial Dysfunction from Atherothrombotic Specimens

2021 ◽  
Author(s):  
Susan Gallogly ◽  
Takeshi Fujisawa ◽  
John D. Hung ◽  
Mairi Brittan ◽  
Elizabeth M. Skinner ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
In Vitro Model ◽  
Umbilical Vein ◽  
Coronary Syndrome ◽  
Coronary Endothelial Cells ◽  
Vitro Model ◽  
Umbilical Vein Endothelial Cells

Abstract Purpose Endothelial dysfunction is central to the pathogenesis of acute coronary syndrome. The study of diseased endothelium is very challenging due to inherent difficulties in isolating endothelial cells from the coronary vascular bed. We sought to isolate and characterise coronary endothelial cells from patients undergoing thrombectomy for myocardial infarction to develop a patient-specific in vitro model of endothelial dysfunction. Methods In a prospective cohort study, 49 patients underwent percutaneous coronary intervention with thrombus aspiration. Specimens were cultured, and coronary endothelial outgrowth (CEO) cells were isolated. CEO cells, endothelial cells isolated from peripheral blood, explanted coronary arteries, and umbilical veins were phenotyped and assessed functionally in vitro and in vivo. Results CEO cells were obtained from 27/37 (73%) atherothrombotic specimens and gave rise to cells with cobblestone morphology expressing CD146 (94 ± 6%), CD31 (87 ± 14%), and von Willebrand factor (100 ± 1%). Proliferation of CEO cells was impaired compared to both coronary artery and umbilical vein endothelial cells (population doubling time, 2.5 ± 1.0 versus 1.6 ± 0.3 and 1.2 ± 0.3 days, respectively). Cell migration was also reduced compared to umbilical vein endothelial cells (29 ± 20% versus 85±19%). Importantly, unlike control endothelial cells, dysfunctional CEO cells did not incorporate into new vessels or promote angiogenesis in vivo. Conclusions CEO cells can be reliably isolated and cultured from thrombectomy specimens in patients with acute coronary syndrome. Compared to controls, patient-derived coronary endothelial cells had impaired capacity to proliferate, migrate, and contribute to angiogenesis. CEO cells could be used to identify novel therapeutic targets to enhance endothelial function and prevent acute coronary syndromes.

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