Imaging fibrin formation and platelet and endothelial cell activation in vivo

SummaryOver the past six decades research employing in vitro assays has identified enzymes, cofactors, cell receptors and associated ligands important to the haemostatic process and its regulation. These studies have greatly advanced our understanding of the molecular and cellular bases of haemostasis and thrombosis. However, in vitro assays cannot simultaneously reproduce the interactions of all of the components of the haemostatic process that occur in vivo nor do they reflect the importance of haemodynamic factors resulting from blood flow. To overcome these limitations investigators have increasingly turned to animal models of haemostasis and thrombosis. In this article we describe some advances in the visualisation of platelet and endothelial cell activation and blood coagulation in vivo and review what we have learned from our intravital microscopy experiments using primarily the laser-induced injury model for thrombosis.

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Biocompatibility and Inflammation Profile of B2A-Coated Granules Used in Arthrodesis

International Journal of Toxicology ◽

10.1177/1091581813476960 ◽

2013 ◽

Vol 32 (2) ◽

pp. 154-161 ◽

Cited By ~ 2

Author(s):

Paul O. Zamora ◽

Yi Liu ◽

Henry Guo ◽

Xinhua Lin

Keyword(s):

Endothelial Cell ◽

Cell Activation ◽

Skin Irritation ◽

Leukocyte Recruitment ◽

Delayed Type Hypersensitivity ◽

Endothelial Cell Activation ◽

Air Pouch ◽

Coated Granules

The biocompatibility/inflammation profile of B2A-coated ceramic granules was evaluated using a panel of standard biocompatibility protocols (International Organization for Standardization-10993) including skin irritation and delayed-type hypersensitivity (Kligman maximization test), as well as acute, subacute, and chronic toxicity. Additionally, the potential of B2A-coated granules to elicit inflammatory reactions was also assessed using in vivo air pouch models, and B2A was evaluated using in vitro models of leukocyte recruitment and endothelial cell activation. Overall, the findings demonstrate that B2A-coated ceramic granules exhibit good biocompatibility profiles in the murine air pouch model and in standard subcutaneous implant models, and B2A did not demonstrate evidence of leukocyte recruitment or endothelial cell activation. These findings suggest that B2A and B2A-coated granules have little, if any, propensity to initiate inflammation reactions based on leukocyte recruitment. Thus, traditional biocompatibility and specially designed inflammation models indicate a high degree of biocompatibility and a low possibility of toxicity, inflammation, or edema following the implant of B2A-coated granules.

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Antithrombin protects against Plasmodium falciparum histidine-rich protein II-mediated inflammation and coagulation

Blood Advances ◽

10.1182/bloodadvances.2021005836 ◽

2021 ◽

Author(s):

Indranil Biswas ◽

Sumith R Panicker ◽

Hemant Giri ◽

Xiaofeng S Cai ◽

Alireza R Rezaie

Keyword(s):

Endothelial Cells ◽

Plasmodium Falciparum ◽

Endothelial Cell ◽

Animal Models ◽

Cell Activation ◽

Histone H3 ◽

Neutrophil Infiltration ◽

Human Neutrophils ◽

Endothelial Cell Activation

Plasmodium falciparum (Pf)-derived histidine-rich protein II (HRPII) has been shown to inhibit heparin-dependent anticoagulant activity of antithrombin (AT) and induce inflammation in vitro and in vivo. In a recent study, we showed that HRPII interacts with the AT-binding vascular glycosaminoglycans (GAGs) to not only disrupt the barrier-permeability function of endothelial cells but also inhibit the anti-inflammatory signaling function of AT. Here we investigated the mechanisms of the pro-inflammatory function of HRPII and the protective activity of AT in cellular and animal models. We found that AT competitively inhibits the GAG-dependent HRPII-mediated activation of NF-κB and expression of intercellular cell adhesion molecule 1 (ICAM1) in endothelial cells. Furthermore, AT inhibits HRPII-mediated histone H3 citrullination and neutrophil extracellular trap (NET) formation in HL60 cells and freshly isolated human neutrophils. In vivo, HRPII induced Mac1 expression on blood neutrophils, MPO release in plasma, neutrophil infiltration and histone H3 citrullination in the lung tissues. HRPII also induced endothelial cell activation as measured by increased ICAM1 expression and elevated vascular permeability in the lungs. AT effectively inhibited HRPII-mediated neutrophil infiltration, NET formation and endothelial cell activation in vivo. AT also inhibited HRPII-meditated deposition of platelets and fibrin(ogen) in the lungs and circulating level of von Willebrand factor in the plasma. We conclude that AT exerts protective effects against pathogenic effects of Pf-derived HRPII in both cellular and animal models.

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432. How do antiphospholipid antibodies contribute to preeclampsia?

Reproduction Fertility and Development ◽

10.1071/srb08abs432 ◽

2008 ◽

Vol 20 (9) ◽

pp. 112

Author(s):

Q. Chen ◽

C. Viall ◽

P. R. Stone ◽

L. W. Chamley

Keyword(s):

Endothelial Cell ◽

Antiphospholipid Antibodies ◽

Cell Activation ◽

Fold Increase ◽

First Trimester ◽

Endothelial Activation ◽

Maternal Blood ◽

Endothelial Cell Activation

Preeclampsia is characterised by elevated maternal blood pressure which is preceded by endothelial activation. The cause of this endothelial cell dysfunction is unclear but it appears to be triggered by a placental factor. One of the risk factors for developing preeclampsia is the presence of antiphospholipid antibodies (aPL) in the maternal blood but exactly how aPL predispose women to developing preeclampsia is unclear. A second feature known to be associated with preeclampsia is excessive shedding and deportation of dead trophoblasts. We have previously shown that shed trophoblasts are phagocytosed by endothelial cells and that phagocytosis of necrotic trophoblasts leads to endothelial cell activation1. In this study we examined the hypothesis that aPL alter the number or nature of trophoblasts shed from the placenta resulting in endothelial cell activation. Using our published model of trophoblast shedding 2 human first trimester placental explants were treated with monoclonal aPL, IIC5 or ID2, or control antibody CD45 for 72 h. Shed trophoblasts then were harvested and counted using a Cellometer AutoT4 automated cell counter. The activity of caspases 3&7 was analysed in all treated shed trophoblasts using a FLICA™ kit. The treated shed trophoblasts also were exposed to the endothelial cell line HMEC-1 for 24 h. The level of ICAM-1 by HMEC-1 was determined by cell-based ELISA. The number of trophoblasts shed from placental explants was increased 2 fold following aPL treatment whereas, treatment with CD45 resulted in only a 1.3 fold increase in shedding. Trophoblasts shed from aPL-treated explants contained less active caspases 3 & 7 compared with control shed trophoblasts. Moreover, phagocytosis of trophoblasts shed from aPL-treated explants induced significantly increased expression of ICAM-1 compared with controls. aPL treatment affected the number and nature of trophoblasts shed from placentae in such a way that phagocytosing endothelium become activated. These findings suggest that aPL treatment may have shifted the type of cell death that shed trophoblasts are undergoing from apoptosis to a more necrotic or aponecrotic mechanism. This type of shedding of trophoblasts in vivo might contribute to the endothelial cell activation which is a hallmark feature of preeclampsia. (1) Chen Q, Stone PR, McCowan LM et al. Phagocytosis of necrotic but not apoptotic trophoblasts induces endothelial cell activation. Hypertension. 2006;47:116–121. (2) Abumaree MH, Stone PR, Chamley LW. An in vitro model of human placental trophoblast deportation/shedding. Mol Hum Reprod. 2006;12:687–694.

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Functional interactions of T cells with endothelial cells: the role of CD40L-CD40-mediated signals.

Journal of Experimental Medicine ◽

10.1084/jem.182.6.1857 ◽

1995 ◽

Vol 182 (6) ◽

pp. 1857-1864 ◽

Cited By ~ 194

Author(s):

M J Yellin ◽

J Brett ◽

D Baum ◽

A Matsushima ◽

M Szabolcs ◽

...

Keyword(s):

T Cells ◽

Endothelial Cells ◽

Endothelial Cell ◽

Cell Surface ◽

Cell Activation ◽

Endothelial Cell Activation ◽

Cd40 Expression

CD40 is expressed on a variety of cells, including B cells, monocytes, dendritic cells, and fibroblasts. CD40 interacts with CD40L, a 30-33-kD activation-induced CD4+ T cell surface molecule. CD40L-CD40 interactions are known to play key roles in B cell activation and differentiation in vitro and in vivo. We now report that normal human endothelial cells also express CD40 in situ, and CD40L-CD40 interactions induce endothelial cell activation in vitro. Frozen sections from normal spleen, thyroid, skin, muscle, kidney, lung, or umbilical cord were studied for CD40 expression by immunohistochemistry. Endothelial cells from all tissues studied express CD40 in situ. Moreover, human umbilical vein endothelial cells (HUVEC) express CD40 in vitro, and recombinant interferon gamma induces HUVEC CD40 upregulation. CD40 expression on HUVEC is functionally significant because CD40L+ Jurkat T cells or CD40L+ 293 kidney cell transfectants, but not control cells, upregulate HUVEC CD54 (intercellular adhesion molecule-1), CD62E (E-selectin), and CD106 (vascular cell adhesion molecule-1) expression in vitro. Moreover, the kinetics of CD40L-, interleukin 1-, or tumor necrosis factor alpha-induced CD54, CD62E, and CD106 upregulation on HUVEC are similar. Finally, CD40L-CD40 interactions do not induce CD80, CD86, or major histocompatibility complex class II expression on HUVEC in vitro. These results demonstrate that CD40L-CD40 interactions induce endothelial cell activation in vitro. Moreover, they suggest a mechanism by which activated CD4+ T cells may augment inflammatory responses in vivo by upregulating the expression of endothelial cell surface adhesion molecules.

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Integrin αVβ3as a Target for Blocking HIV-1 Tat-Induced Endothelial Cell Activation In Vitro and Angiogenesis In Vivo

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/01.atv.0000186182.14908.7b ◽

2005 ◽

Vol 25 (11) ◽

pp. 2315-2320 ◽

Cited By ~ 33

Author(s):

Chiara Urbinati ◽

Stefania Mitola ◽

Elena Tanghetti ◽

Chandra Kumar ◽

Johannes Waltenberger ◽

...

Keyword(s):

Endothelial Cell ◽

Cell Activation ◽

Endothelial Cell Activation ◽

Hiv 1

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The In Vitro and In Vivo Effects of Anti-Galactose Antibodies on Endothelial Cell Activation and Xenograft Rejection

The Journal of Immunology ◽

10.4049/jimmunol.170.3.1531 ◽

2003 ◽

Vol 170 (3) ◽

pp. 1531-1539 ◽

Cited By ~ 26

Author(s):

Hui Xu ◽

Dengping Yin ◽

Bashoo Naziruddin ◽

Libing Chen ◽

Aileen Stark ◽

...

Keyword(s):

Endothelial Cell ◽

Cell Activation ◽

Endothelial Cell Activation ◽

Xenograft Rejection ◽

In Vivo Effects

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Cholinergic stimulation blocks endothelial cell activation and leukocyte recruitment during inflammation

Journal of Experimental Medicine ◽

10.1084/jem.20040463 ◽

2005 ◽

Vol 201 (7) ◽

pp. 1113-1123 ◽

Cited By ~ 331

Author(s):

Rubina W. Saeed ◽

Santosh Varma ◽

Tina Peng-Nemeroff ◽

Barbara Sherry ◽

David Balakhaneh ◽

...

Keyword(s):

Endothelial Cell ◽

Cell Activation ◽

Leukocyte Recruitment ◽

Dependent Manner ◽

Cholinergic Stimulation ◽

Endothelial Cell Activation ◽

Cholinergic Agonists ◽

Α7 Nachr

Endothelial cell activation plays a critical role in regulating leukocyte recruitment during inflammation and infection. Based on recent studies showing that acetylcholine and other cholinergic mediators suppress the production of proinflammatory cytokines via the α7 nicotinic acetylcholine receptor (α7 nAChR) expressed by macrophages and our observations that human microvascular endothelial cells express the α7 nAChR, we examined the effect of cholinergic stimulation on endothelial cell activation in vitro and in vivo. Using the Shwartzman reaction, we observed that nicotine (2 mg/kg) and the novel cholinergic agent CAP55 (12 mg/kg) inhibit endothelial cell adhesion molecule expression. Using endothelial cell cultures, we observed the direct inhibitory effects of acetylcholine and cholinergic agents on tumor necrosis factor (TNF)-induced endothelial cell activation. Mecamylamine, an nAChR antagonist, reversed the inhibition of endothelial cell activation by both cholinergic agonists, confirming the antiinflammatory role of the nAChR cholinergic pathway. In vitro mechanistic studies revealed that nicotine blocked TNF-induced nuclear factor–κB nuclear entry in an inhibitor κB (IκB)α- and IκBε-dependent manner. Finally, with the carrageenan air pouch model, both vagus nerve stimulation and cholinergic agonists significantly blocked leukocyte migration in vivo. These findings identify the endothelium, a key regulator of leukocyte trafficking during inflammation, as a target of anti-inflammatory cholinergic mediators.

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Ethanol Blocks Leukocyte Recruitment and Endothelial Cell Activation In Vivo and In Vitro

The Journal of Immunology ◽

10.4049/jimmunol.173.10.6376 ◽

2004 ◽

Vol 173 (10) ◽

pp. 6376-6383 ◽

Cited By ~ 60

Author(s):

Rubina W. Saeed ◽

Santosh Varma ◽

Tina Peng ◽

Kevin J. Tracey ◽

Barbara Sherry ◽

...

Keyword(s):

Endothelial Cell ◽

Cell Activation ◽

Leukocyte Recruitment ◽

Endothelial Cell Activation

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In Vitro Models of Angiogenesis: The use of Matrigel

The International Journal of Biological Markers ◽

10.1177/172460089901400408 ◽

1999 ◽

Vol 14 (4) ◽

pp. 243-246 ◽

Cited By ~ 52

Author(s):

R. Benelli ◽

A. Albini

Keyword(s):

Growth Factors ◽

Endothelial Cell ◽

Basement Membrane ◽

Cell Activation ◽

In Vitro Models ◽

In Vitro Assays ◽

Short Report ◽

Neoplastic Progression ◽

Endothelial Cell Activation

Tumor-induced angiogenesis is a key event for neoplastic progression. In vitro assays are important for identification of potential angiogenic agents and rapid sceening for pharmacological inhibitors. The increased interest in this field of study has generated several in vitro assays that recapitulate the steps of endothelial cell activation and differentiation. In this short report we emphasize the utility of Matrigel, a reconstituted basement membrane, to define two different steps in the angiogenic process: invasion in response to growth factors and organization of microvessels into a network with branching morphology on a Matrigel substrate.

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