Home About us Contact
|
Home About us Contact | ||
|
|
||
Human Aortic Endothelial Cells (human aortic + endothelial_cell)
Selected AbstractsInitiation and propagation of coagulation from tissue factor-bearing cell monolayers to plasma: initiator cells do not regulate spatial growth rate,JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 2 2005M. V. OVANESOV Summary., Exposure of tissue factor (TF)-bearing cells to blood is the initial event in coagulation and intravascular thrombus formation. However, the mechanisms which determine thrombus growth remain poorly understood. To explore whether the procoagulant activity of vessel wall-bound cells regulates thrombus expansion, we studied in vitro spatial clot growth initiated by cultured human cells of different types in contact pathway-inhibited, non-flowing human plasma. Human aortic endothelial cells, smooth muscle cells, macrophages and lung fibroblasts differed in their ability to support thrombin generation in microplate assay with peaks of generated thrombin of 60 ± 53 nmol L,1, 135 ± 57 nmol L,1, 218 ± 55 nmol L,1 and 407 ± 59 nmol L,1 (mean ± SD), respectively. Real-time videomicroscopy revealed the initiation and spatial growth phases of clot formation. Different procoagulant activity of cell monolayers was manifested as up to 4-fold difference in the lag times of clot formation. In contrast, the clot growth rate, which characterized propagation of clotting from the cell surface to plasma, was largely independent of cell type (, 30% difference). Experiments with factor VII (FVII)-, FVIII-, FX- or FXI-deficient plasmas and annexin V revealed that (i) cell surface-associated extrinsic Xase was critical for initiation of clotting; (ii) intrinsic Xase regulated only the growth phase; and (iii) the contribution of plasma phospholipid surfaces in the growth phase was predominant. We conclude that the role of TF-bearing initiator cells is limited to the initial stage of clot formation. The functioning of intrinsic Xase in plasma provides the primary mechanism of sustained and far-ranging propagation of coagulation leading to the physical expansion of a fibrin clot. [source] Actin stress fiber pre-extension in human aortic endothelial cellsCYTOSKELETON, Issue 4 2008Lan Lu Abstract Actin stress fibers (SFs) enable cells to sense and respond to mechanical stimuli and affect adhesion, motility and apoptosis. We and others have demonstrated that cultured human aortic endothelial cells (HAECs) are internally stressed so that SFs are pre-extended beyond their unloaded lengths. The present study explores factors affecting SF pre-extension. In HAECs cultured overnight the baseline pre-extension was 1.10 and independent of the amount of cell shortening. Decreasing contractility with 30 mM BDM or 10 ,M blebbistatin decreased pre-extension to 1.05 whereas increasing contractility with 2 nM calyculin A increased pre-extension to 1.26. Knockdown of ,-actinin-1 with an interfering RNA increased pre-extension to 1.28. None of these affected the wavelength of the buckled SFs. Pre-extension was the same in unperturbed cells as in those in which the actin cytoskeleton was disrupted by both chemical and mechanical means and then allowed to reassemble. Finally, disrupting MTs or IFs did not affect pre-extension but increased the wavelength. Taken together, these results suggest that pre-extension of SFs is determined primarily by intrinsic factors, i.e. the level of actin-myosin interaction. This intrinsic control of pre-extension is sufficiently robust that pre-extension is the same even after the actin cytoskeleton has been disrupted and reorganized. Unlike pre-extension, the morphology of the compressed SFs is partially determined by MTs and IFs which appear to support the SFs along their lengths. Cell Motil. Cytoskeleton 2008. © 2008 Wiley-Liss, Inc. [source] Interaction of endothelial cells with self-assembled monolayers for potential use in drug-eluting coronary stentsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Gopinath Mani Abstract Drug-eluting stents (DES) are implanted in patients to treat in-stent restenosis. Commercially available DES use polymers for coating and releasing drugs. Several studies have showed that polymer coatings cause adverse reactions. Delayed endothelialization of polymer-coated DES leads to late stent thrombosis. Recently, the potential for using self-assembled monolayers (self-assembled monolayers (SAMs),organic constructs composed of (a) chemical groups which attach to metal surfaces, (b) long hydrocarbon chains, and (c) terminal functional groups) as an alternate drug delivery system for coronary stents has been demonstrated. In this study, the interaction of human aortic endothelial cells (HAECs) with SAMs and therapeutic SAMs (therapeutic self-assembled monolayers (TSAMs),SAMs derivatized with the drug, flufenamic acid) was investigated. HAECs were cultured on plain glass, control, SAMs-, and TSAMs-coated titanium (Ti) and gold (Au) specimens. The viability and proliferation of HAECs were investigated using MTT colorimetric assay. The adhesion of HAECs on SAMs and TSAMs was equivalent to that of control metal surfaces and superior to that of plain glass surfaces. The cells continued to proliferate on both SAMs and TSAMs even though the rate of proliferation was slower than plain glass or control-Ti. The spreading of HAECs on TSAMs with typical polygonal shape indicated that these surfaces are conducive to endothelialization. The expression of surface adhesion protein, platelet endothelial cell adhesion molecule-1, on TSAMs indicated that the endothelial cells preserved their phenotype on these surfaces. Thus, this study demonstrated that SAMs and TSAMs do not elicit an adverse response from endothelial cells in in vitro conditions. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Salvianolic acid B attenuates VCAM-1 and ICAM-1 expression in TNF-,-treated human aortic endothelial cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2001Yung-Hsiang Chen Abstract Attachment to, and migration of leukocytes into the vessel wall is an early event in atherogenesis. Expression of cell adhesion molecules by the arterial endothelium may play a major role in atherosclerosis. It has been suggested that antioxidants inhibit the expression of adhesion molecules and may thus attenuate the processes leading to atherosclerosis. In the present study, the effects of a potent water-soluble antioxidant, salvianolic acid B (Sal B), and an aqueous ethanolic extract (SME), both derived from a Chinese herb, Salvia miltiorrhiza, on the expression of endothelial-leukocyte adhesion molecules by tumor necrosis factor-, (TNF-,)-treated human aortic endothelial cells (HAECs) were investigated. When pretreated with SME (50 and 100 ,g/ml), the TNF-,-induced expression of vascular adhesion molecule-1 (VCAM-1) was notably attenuated (77.2,±,3.2% and 80.0,±,2.2%, respectively); and with Sal B (1, 2.5, 5, 10, and 20 ,g/ml), 84.5,±,1.9%, 78.8,±,1.2%, 58.9,±,0.4%, 58.7,±,0.9%, and 57.4,±,0.3%, respectively. Dose-dependent lowering of expression of intercellular cell adhesion molecule-1 (ICAM-1) was also seen with SME or Sal B. In contrast, the expression of endothelial cell selectin (E-selectin) was not affected. SME (50 ,g/ml) or Sal B (5 ,g/ml) significantly reduced the binding of the human monocytic cell line, U937, to TNF-,-stimulated HAECs (45.7,±,2.5% and 55.8,±,1.2%, respectively). SME or Sal B significantly inhibited TNF-,-induced activation of nuclear factor kappa B (NF-,B) in HAECs (0.36- and 0.48-fold, respectively). These results demonstrate that SME and Sal B have anti-inflammatory properties and may explain their anti-atherosclerotic properties. This new mechanism of action of Sal B and SME, in addition to their previously reported inhibition of LDL, may help explain their efficacy in the treatment of atherosclerosis. J. Cell. Biochem. 82:512,521, 2001. © 2001 Wiley-Liss, Inc. [source] Composite Islet-Endothelial Cell Grafts: A Novel Approach to Counteract Innate Immunity in Islet TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2005Ulrika Johansson An instant blood-mediated inflammatory reaction (IBMIR) is elicited when islets come in contact with blood after intraportal transplantation. In contrast, endothelial cells (EC) readily tolerate contact with blood. A conceivable strategy to overcome IBMIR would be to create composite islet-EC grafts. Human islets were co-cultured with primary human aortic endothelial cells (HAEC) for 2,7 days to obtain 50,90% coverage. HAEC-coated islets were exposed to ABO-identical blood and analyzed with regard to clotting time, signs of inflammation and cell infiltration. Composite islet-HAEC graft survival was assessed after transplantation to athymic (nu/nu) nude mice. Exposed to blood, HAEC-coated islets induced less activation of coagulation and complement compared to control islets. Also, platelet and leukocyte consumption in blood was decreased. Clots with entrapped HAEC-coated islets showed less infiltration of CD11b+ cells. The extent of protection correlated to the level of HAEC coverage. Transplanted composite grafts stained positive for insulin and PECAM-1 demonstrating presence of both islets and HAEC within the islet graft 7 weeks after transplantation. Composite islet-HAEC grafts reduce all components of IBMIR. Refinement of the technique will allow introduction of composite islet-EC grafts in clinical islet transplantation, using autologous EC expanded in vitro and kept frozen until allogeneic islets become available for that specific recipient. [source] Reactivity of ,/, T cells to human 60-kd heat-shock protein and their cytotoxicity to aortic endothelial cells in Takayasu arteritisARTHRITIS & RHEUMATISM, Issue 8 2007Sunil Kumar Chauhan Objective Increased numbers of circulating ,/, T cells with a restricted T cell receptor repertoire, as well as colocalization of the expression of heat-shock protein Hsp60/65 and ,/, T cells in the arterial lesions of patients with Takayasu arteritis (TA), indicate that ,/, T cells may react to Hsp60 and cause damage to the arterial endothelium. In this study we investigated the proliferative responses of ,/, T cells to human Hsp60 and their cytotoxicity to human aortic endothelial cells (ECs) in patients with TA. Methods Blood samples were obtained from 12 patients with TA, 8 patients with systemic lupus erythematosus (SLE) (as disease controls), and 10 healthy control subjects. Proliferative responses of circulating ,/, T cells to human Hsp60 were detected by flow cytometry,based bromodeoxyuridine incorporation assay. Cytotoxicity of the ,/, T cells to human aortic ECs was analyzed by colorimetric lactate dehydrogenase release assay. Results The ,/, T cells of 11 of 12 patients with TA exhibited reactivity to Hsp60, whereas none of the ,/, T cells from patients with SLE or healthy controls showed reactivity (both P < 0.001). The mean ± SD proliferative response of ,/, T cells in patients with TA was 21.4 ± 11.3%, compared with 4.2 ± 1.2% in patients with SLE and 4.01 ± 1.82% in healthy controls (both P < 0.001). In addition, compared with the control groups, the ,/, T cells of patients with TA had increased spontaneous cytotoxicity to aortic ECs (22.1 ± 15.0% versus 9.6 ± 2.13% in SLE patients and 8.1 ± 4.7% in healthy controls; both P < 0.005), which was further enhanced following stimulation of ,/, T cells with Hsp60. The cytotoxicity of the ,/, T cells was significantly inhibited by treatment of these cells with concanamycin A and anti,Fas ligand,blocking antibodies. Conclusion The results show that ,/, T cells in patients with TA are reactive to Hsp60 and exhibit cytotoxicity to aortic ECs, suggesting a key role of Hsp60 and ,/, T cells in the pathogenesis of TA. [source] Inhibition of angiotensin-converting enzyme protects endothelial cell against hypoxia/reoxygenation injuryBIOFACTORS, Issue 4 2000Noriko Fujita Abstract Cardiovascular tissue injury in ischemia/reperfusion has been shown to be prevented by angiotensin-converting enzyme (ACE) inhibitors. However, the mechanism on endothelial cells has not been assessed in detail. Cultured human aortic endothelial cells (HAEC) were exposed to hypoxia with or without reoxygenation. Hypoxia enhanced apoptosis along with the activation of caspase-3. Reoxygenation increased lactate dehydrogenase release time-dependently, along with an increase of intracellular oxygen radicals. ACE inhibitor quinaprilat and bradykinin significantly lessened apoptosis and lactate dehydrogenase release with these effects being diminished by a kinin B2 receptor antagonist and a nitric oxide synthase inhibitor. In conclusion, hypoxia activated the suicide pathway leading to apoptosis of HAEC by enhancing caspase-3 activity, while subsequent reoxygenation induced necrosis by enhancing oxygen radical production. Quinaprilat could ameliorate both apoptosis and necrosis through the upregulation of constitutive endothelial nitric oxide synthase via an increase of bradykinin, with the resulting increase of nitric oxide. [source] The endothelial cells downregulate the generation of factor VIIa through EPCR bindingBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2010Cristina Puy Summary Traces of activated factor VII (FVIIa) are required to maintain haemostasis. Activated factor X (FXa) is the main activator of FVII in the absence of tissue factor. However, little is known about how this mechanism is regulated. We and others reported the interaction between FVII and the endothelial cell protein C receptor (EPCR). We have analysed the role of EPCR in the FXa-dependent FVIIa generation. Activation was performed on the surface of human aortic endothelial cells in the presence or absence of a blocking anti-EPCR monoclonal antibody (mAb). Western-blot analyses revealed that FVII activation was increased twofold upon EPCR blocking. Kinetic analyses revealed that blocking doubled the catalytic efficiency for activation. Protein C was unable to mimic the effect of the anti-EPCR mAb on activation. Surface plasmon resonance experiments revealed that binding of EPCR and phospholipids to FVII were mutually exclusive. The 50% inhibitory concentration value for phospholipids to reduce the binding of FVIIa to EPCR was 57·67 ± 0·11 ,mol/l. Immunofluorescence experiments showed that EPCR and phosphatidylserine are located at different regions of the cell surface. We propose that EPCR downregulates FVII activation by moving it from phosphatidylserine-rich regions. In summary, this study described a new anticoagulant role for EPCR. [source] Statins suppress interleukin-6-induced monocyte chemo-attractant protein-1 by inhibiting Janus kinase/signal transducers and activators of transcription pathways in human vascular endothelial cellsBRITISH JOURNAL OF PHARMACOLOGY, Issue 6 2010Michihisa Jougasaki Background and purpose:, The mechanisms of anti-inflammatory actions of statins, 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase inhibitors, remain unclear. We investigated the effects of statins on interleukin (IL)-6-induced monocyte chemo-attractant protein (MCP)-1 expression and monocyte chemotaxis. Experimental approach:, Cultures of human aortic endothelial cells (HAECs) were stimulated with IL-6 in the absence and presence of statins. Gene expression and protein secretion of MCP-1, phosphorylation of Janus kinase (JAK) and the signal transducers and activators of transcription (STAT) pathway, and human monocyte migration were examined. Key results:, IL-6 plus its soluble receptor sIL-6R (IL-6/sIL-6R) promoted THP-1 monocyte migration, and increased gene expression and protein secretion of MCP-1, more than IL-6 alone or sIL-6R alone. Various statins inhibited IL-6/sIL-6R-promoted monocyte migration and MCP-1 expression in HAECs. Co-incubation of mevalonate and geranylgeranyl pyrophosphate, but not farnesyl pyrophosphate, reversed the inhibitory effects of statins on MCP-1 expression. Geranylgeranyl transferase inhibitor, but not farnesyl transferase inhibitor, suppressed IL-6/sIL-6R-stimulated MCP-1 expression. IL-6/sIL-6R rapidly phosphorylated JAK1, JAK2, TYK2, STAT1 and STAT3, which were inhibited by statins. Transfection of STAT3 small interfering RNA (siRNA), but not STAT1 siRNA, attenuated the ability of IL-6/sIL-6R to enhance THP-1 monocyte migration. In addition, statins blocked IL-6/sIL-6R-induced translocation of STAT3 to the nucleus. Conclusions and implications:, Statins suppressed IL-6/sIL-6R-induced monocyte chemotaxis and MCP-1 expression in HAECs by inhibiting JAK/STAT signalling cascades, explaining why statins have anti-inflammatory properties beyond cholesterol reduction. [source] | |||||||||||||