Platelet-vessel wall interactions in atherosclerotic disease

2008 ◽  
Vol 99 (03) ◽  
pp. 480-486 ◽  
Author(s):  
Harald Langer ◽  
Meinrad Gawaz
Keyword(s):  
Platelet Adhesion ◽  
Plaque Rupture ◽  
Vascular Inflammation ◽  
Atherosclerotic Lesion ◽  
Vascular Wall ◽  
Atherosclerotic Disease ◽  
Proinflammatory Mediators ◽  
Negative Feedback Loops ◽  
Progression Of Disease

SummaryDuring the prolonged course of atherosclerotic disease,platelets are of central importance as they contribute to the initiation of the disease, to its progression and acute exacerbation but also provide potential regenerative mechanisms. Platelets secrete chemokines and cytokines that mediate vascular inflammation and are in turn activated by substances released from cells of the vascular wall.These interactions represent positive and negative feedback loops, which in case of dysregulation may lead to development and progression of disease. Furthermore, platelet adhesion to the endothelium is critical for the initiation of atherosclerotic lesion formation in vivo. Even prior to endothelial denudation, platelet adhesion governed by disturbed flow at predilection sites for atherosclerosis induces recruitment of proathe- rosclerotic cells and release of proinflammatory mediators from all involved cell types.Finally,the pathogenetic role of platelets for late atheroclerotic events including plaque rupture, microembolism or spasms within the microcirculation is well established. However, increasing evidence indicates that platelets mediate on the other hand potential regenerative mechanisms. Platelets recruit circulating progenitor cells to sites of vascular injury. Furthermore, they influence their biological activity and maturation. Therefore,platelets contribute at all stages of vascular disease by interfering with highly dynamic processes. Understanding interactions of platelets with other circulating cells and the vascular wall is a prerequisite to understand cardiovascular disease and to identify potential therapeutic targets.

scholarly journals Endogenous Ceramide Contributes to the Transcytosis of oxLDL across Endothelial Cells and Promotes Its Subendothelial Retention in Vascular Wall

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Wenjing Li ◽  
Xiaoyan Yang ◽  
Shasha Xing ◽  
Fang Bian ◽  
Wanjing Yao ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Vascular Endothelial Cells ◽  
Atherosclerotic Lesion ◽  
Vascular Wall ◽  
Acid Sphingomyelinase ◽  
Synthesis Inhibitor ◽  
Ceramide Production

Oxidized low density of lipoprotein (oxLDL) is the major lipid found in atherosclerotic lesion and elevated plasma oxLDL is recognized to be a risk factor of atherosclerosis. Whether plasma oxLDL could be transported across endothelial cells and initiate atherosclerotic changes remains unknown. In an establishedin vitrocellular transcytosis model, the present study found that oxLDL could traffic across vascular endothelial cells and further that the regulation of endogenous ceramide production by ceramide metabolizing enzyme inhibitors significantly altered the transcytosis of oxLDL across endothelial cells. It was found that acid sphingomyelinase inhibitor, desipramine (DES), andde novoceramide synthesis inhibitor, myriocin (MYR), both decreasing the endogenous ceramide production, significantly inhibited the transcytosis of oxLDL. Ceramidase inhibitor, N-oleoylethanolamine (NOE), and sphingomyelin synthase inhibitor, O-Tricyclo[5.2.1.02,6]dec-9-yl dithiocarbonate potassium salt (D609), both increasing the endogenous ceramide production, significantly upregulated the transcytosis of oxLDL.In vivo, injection of fluorescence labeled oxLDL into mice body also predisposed to the subendothelial retention of these oxidized lipids. The observations provided in the present study demonstrate that endogenous ceramide contributes to the transcytosis of oxLDL across endothelial cells and promotes the initiating step of atherosclerosis—the subendothelial retention of lipids in vascular wall.

scholarly journals The P387 Thrombospondin-4 Variant Promotes Accumulation of Macrophages in Atherosclerotic Lesions

2019 ◽  
Author(s):  
Santoshi Muppala ◽  
Mohammed Tanjimur Rahman ◽  
Irene Krukovets ◽  
Dmitriy Verbovetskiy ◽  
Elzbieta Pluskota ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Smooth Muscle Actin ◽  
Vascular Inflammation ◽  
Cutting Temperature ◽  
Vascular Wall ◽  
Alpha Smooth Muscle Actin ◽  
Knock Out ◽  
Atherosclerotic Lesions ◽  
Thrombospondin 4

AbstractAimsThrombopspondin-4 (TSP4) is a pro-angiogenic protein that has been implicated in tissue remodeling and local vascular inflammation. TSP4 and, in particular, its SNP variant, P387 TSP4, have been associated with cardiovascular disease.Macrophages are central to initiation and resolution of inflammation and development of atherosclerotic lesions, but the effects of the P387 TSP4 on macrophages remain essentially unknown. We examined the effects of the P387 TSP4 variant on macrophages in cell culture andin vivoin a murine model of atherosclerosis. Further, the levels and distributions of the twoTSP4 variants were assessed in human atherosclerotic arteries.Methods and ResultsInApoE−/−/P387-TSP4 knock-in mice, atherosclerotic lesions accumulated more macrophages than lesions bearing A387 TSP4. The levels of inflammatory markers were increased in lesions ofApoE−/−/P387-TSP4 knock-in mice compared toApoE−/−mice. Lesions in human arteries from individuals carrying the P387 variant had higher levels of TSP4 and higher macrophage accumulation. P387 TSP4 was more active in supporting adhesion of cultured human and mouse macrophages in experiments using recombinant TSP4 variants and in cells derived from P387-TSP4 knock-in mice.ConclusionsTSP4 supports the adhesion of macrophages and their accumulation in atherosclerotic lesions. P387 TSP4 is more active in supporting these pro-inflammatory events in the vascular wall, which may contribute to the increased association of P387 TSP4 with cardiovascular disease.AbbreviationsBSA, bovine serum albumin; DMSO, dimethyl sulfoxide; ECM, extracellular matrix;Thbs4−/−, thrombospondin-4 gene knock-out; WT, wild type; P387-TSP4 KI, P387TSP4knock-in mice; OCT, Optimum Cutting Temperature; vWF, von Willebrand factor; α-SMA, alpha-smooth muscle actin; Egr2, Early Growth Response 2; PBS, Phosphate Buffer saline; DMEM, Dulbecco’s Modified Eagle Medium.

scholarly journals Leukotriene Receptors: Crucial Components in Vascular Inflammation

2007 ◽  
Vol 7 ◽  
pp. 1422-1439 ◽  
Author(s):  
Magnus Bäck
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Vascular Inflammation ◽  
Vascular Wall ◽  
Receptor Activation ◽  
Receptor Expression ◽  
Surface Receptors ◽  
Beneficial Effects

The accumulation of immune cells during vascular inflammation leads to formation of leukotrienes (LTs). While macrophages represent a major source of LT biosynthesis in the proximity of the vascular wall, activated T lymphocytes may, in addition, play a key regulatory role on macrophage expression of LT-forming enzymes. Within the vascular wall, LTs activate cell surface receptors of the BLT and CysLT subtypes expressed on vascular smooth muscle and endothelial cells. The LT receptor expression on those cells is highly dependent on transcriptional regulation by pro- and anti-inflammatory mediators. LT receptor activation on vascular smooth muscle cells is associated with both directly and indirectly induced vasoconstriction, as well as intimal hyperplasia through stimulation of migration and proliferation. On the other hand, endothelial LT receptors induce vasorelaxation and leukocyte recruitment and adhesion. Results fromin vitroandin vivostudies of LT receptor antagonists indicate potential beneficial effects in atherosclerosis and other inflammatory cardiovascular diseases.

scholarly journals A Critical Role of Platelet Adhesion in the Initiation of Atherosclerotic Lesion Formation

2002 ◽  
Vol 196 (7) ◽  
pp. 887-896 ◽  
Author(s):  
Steffen Massberg ◽  
Korbinian Brand ◽  
Sabine Grüner ◽  
Sharon Page ◽  
Elke Müller ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Platelet Adhesion ◽  
Critical Role ◽  
Atherosclerotic Lesion ◽  
Platelet Glycoprotein ◽  
Lesion Formation ◽  
Aortic Sinus ◽  
Major Player ◽  
Atherosclerotic Lesion Formation

The contribution of platelets to the process of atherosclerosis remains unclear. Here, we show in vivo that platelets adhere to the vascular endothelium of the carotid artery in ApoE−/− mice before the development of manifest atherosclerotic lesions. Platelet–endothelial cell interaction involved both platelet glycoprotein (GP)Ibα and GPIIb-IIIa. Platelet adhesion to the endothelium coincides with inflammatory gene expression and preceded atherosclerotic plaque invasion by leukocytes. Prolonged blockade of platelet adhesion in ApoE−/− mice profoundly reduced leukocyte accumulation in the arterial intima and attenuated atherosclerotic lesion formation in the carotid artery bifurcation, the aortic sinus, and the coronary arteries. These findings establish the platelet as a major player in initiation of the atherogenetic process.

Enhanced in vivo platelet adhesion in vasodilator-stimulated phosphoprotein (VASP)–deficient mice

Blood ◽  
2004 ◽  
Vol 103 (1) ◽  
pp. 136-142 ◽  
Author(s):  
Steffen Massberg ◽  
Sabine Grüner ◽  
Ildiko Konrad ◽  
Maisa I. Garcia Arguinzonis ◽  
Martin Eigenthaler ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Protein Kinases ◽  
Platelet Adhesion ◽  
Vascular Wall ◽  
Guanosine Monophosphate ◽  
Wild Type ◽  
Dependent Protein ◽  
Deficient Mice ◽  
Null Mutants

Abstract Platelet adhesion and activation at the vascular wall are the initial steps leading to arterial thrombosis and vascular occlusion. Prostacyclin and nitric oxide inhibit platelet adhesion, acting via cyclic adenosine monophosphate (cAMP)– and cyclic guanosine monophosphate (cGMP)–dependent protein kinases. A major downstream target for both cAMP- and cGMP-dependent protein kinases is the vasodilator-stimulated phosphoprotein (VASP). To test the significance of VASP for the regulation of platelet adhesion in vivo, we studied platelet–vessel wall interactions using VASP-deficient (VASP–/–) mice. Under physiologic conditions, platelet adhesion to endothelial cells was significantly enhanced in VASP null mutants when compared with wild-type mice (P < .05). Platelet recruitment in VASP null mice involved P-selectin and the fibrinogen receptor glycoprotein IIb-IIIa (GPIIb-IIIa). Under pathophysiologic conditions, the loss of VASP increased platelet adhesion to the postischemic intestinal microvasculature, to the atherosclerotic endothelium of ApoE-deficient mice, and to the subendothelial matrix following endothelial denudation (P < .05 vs wild type). Importantly, platelet adhesion in VASP null mutants was unresponsive to nitric oxide. These data show for the first time in vivo that VASP is involved in down-regulation of platelet adhesion to the vascular wall under both physiologic and pathophysiologic conditions.

scholarly journals Fibronectin receptor integrin α5β1 regulates assembly of PP2A complexes through PDE4D: modulation of vascular inflammation and atherosclerosis

2019 ◽  
Author(s):  
Sanguk Yun ◽  
Rui Hu ◽  
Melanie E. Schwaemmle ◽  
Alexander N. Scherer ◽  
Zhenwu Zhuang ◽  
...  
Keyword(s):  
Cell Function ◽  
Vascular Inflammation ◽  
Vascular Wall ◽  
Regulatory Subunit ◽  
Fibronectin Receptor ◽  
Inflammatory Activation ◽  
Integrin Binding Site ◽  
Inhibitory Site ◽  
Specific Regulation

AbstractFibronectin in the vascular wall promotes inflammatory activation of the endothelium during vascular remodeling and atherosclerosis. These effects are mediated in part by fibronectin binding to integrin α5, which recruits and activates phosphodiesterase 4D5 (PDE4D5) by inducing its dephosphorylation on an inhibitory site Ser651. Active PDE then hydrolyzes anti-inflammatory cAMP to facilitate inflammatory signaling. To test this model in vivo, we mutated the integrin binding site in PDE4D5 in mice. This mutation reduced endothelial inflammatory activation in athero-prone regions of arteries, and, in a hyperlipidemia model, reduced atherosclerotic plaque size while increasing markers of plaque stability. We then investigated the mechanism of PDE4D5 activation. Proteomics identified the PP2A regulatory subunit B55α as the factor recruiting PP2A to PDE4D5. The B55α-PP2A complex localized to adhesions and directly dephosphorylated PDE4D5. This interaction also unexpectedly stabilized the PP2A-B55α complex. The integrin-regulated, pro-atherosclerotic transcription factor Yap is also dephosphorylated and activated through this pathway. PDE4D5 therefore mediates matrix-specific regulation of EC phenotype via an unconventional adapter role, assembling and anchoring a multifunctional PP2A complex with other targets. These results are likely to have widespread consequences for control of cell function by integrins.

Involvement of 5-Hydroxytryptamine in Platelet Aggregation In Vivo in Rats and Guinea Pigs

1989 ◽  
Vol 61 (03) ◽  
pp. 463-467 ◽  
Author(s):  
G M Smith
Keyword(s):  
Platelet Count ◽  
Guinea Pigs ◽  
Platelet Adhesion ◽  
Adenosine Diphosphate ◽  
Rate Of Return ◽  
Low Doses ◽  
Dose Dependent ◽  
Higher Doses ◽  
Rat Platelets

SummaryIn this study, 5-hydroxytryptamine (5-HT) caused a dose- dependent fall in the circulating platelet count suggesting that 5-HT receptors are activated in rat platelets to cause platelet adhesion and aggregation. When low doses of adenosine diphosphate (ADP) were simultaneously injected with 5-HT, there was a significant potentiation of the responses to ADR Ketanserin significantly reduced the potentiated responses. When higher doses of ADP were infused with bolus injections of 5-HT there was no potentiation and ketanserin did not reduce these responses. Ketanserin did not inhibit the collagen-induced fall in circulating platelet count, but did significantly increase the rate of return to the basal platelet count compared with control. 5-HT did not cause a fall in platelet count in guinea-pigs

Desmopressin (DDAVP) Enhances Platelet Adhesion to the Extracellular Matrix of Cultured Human Endothelial Cells through Increased Expression of Tissue Factor

1997 ◽  
Vol 77 (05) ◽  
pp. 0975-0980 ◽  
Author(s):  
Angel Gálvez ◽  
Goretti Gómez-Ortiz ◽  
Maribel Díaz-Ricart ◽  
Ginés Escolar ◽  
Rogelio González-Sarmiento ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Tissue Factor ◽  
Platelet Adhesion ◽  
Umbilical Vein ◽  
Procoagulant Activity ◽  
Experimental Conditions ◽  
Chromogenic Assay

SummaryThe effect of desmopressin (DDAVP) on thrombogenicity, expression of tissue factor and procoagulant activity (PCA) of extracellular matrix (ECM) generated by human umbilical vein endothelial cells cultures (HUVEC), was studied under different experimental conditions. HUVEC were incubated with DDAVP (1, 5 and 30 ng/ml) and then detached from their ECM. The reactivity towards platelets of this ECM was tested in a perfusion system. Coverslips covered with DD A VP-treated ECMs were inserted in a parallel-plate chamber and exposed to normal blood anticoagulated with low molecular weight heparin (Fragmin®, 20 U/ml). Perfusions were run for 5 min at a shear rate of 800 s1. Deposition of platelets on ECMs was significantly increased with respect to control ECMs when DDAVP was used at 5 and 30 ng/ml (p <0.05 and p <0.01 respectively). The increase in platelet deposition was prevented by incubation of ECMs with an antibody against human tissue factor prior to perfusion. Immunofluorescence studies positively detected tissue factor antigen on DDAVP derived ECMs. A chromogenic assay performed under standardized conditions revealed a statistically significant increase in the procoagulant activity of the ECMs produced by ECs incubated with 30 ng/ml DDAVP (p <0.01 vs. control samples). Northern blot analysis revealed increased levels of tissue factor mRNA in extracts from ECs exposed to DDAVP. Our data indicate that DDAVP in vitro enhances platelet adhesion to the ECMs through increased expression of tissue factor. A similar increase in the expression of tissue factor might contribute to the in vivo hemostatic effect of DDAVP.

Dynamic Role of Macrophage Sub Types for Development of Atherosclerosis and Potential Use of Herbal Immunomodulators as Imminent Therapeutic Strategy

2020 ◽  
Vol 18 ◽  
Author(s):  
Parimalanandhini Duraisamy ◽  
Sangeetha Ravi ◽  
Mahalakshmi Krishnan ◽  
Catherene M. Livya ◽  
Beulaja Manikandan ◽  
...  
Keyword(s):  
Foam Cell ◽  
Cell Formation ◽  
Atherosclerotic Lesion ◽  
Foam Cell Formation ◽  
Atherosclerosis Progression ◽  
Proinflammatory Mediators ◽  
M1 Macrophage ◽  
Tnf Α ◽  
Inflammatory Site

: Atherosclerosis, a major contributor to cardiovascular disease is a global alarm causing mortality worldwide. Being a progressive disease in the arteries, it mainly causes recruitment of monocytes to the inflammatory sites and subside pathological conditions. Monocyte-derived macrophage mainly acts in foam cell formation by engorging the LDL molecules, oxidizes it into Ox-LDL and leads to plaque deposit development. Macrophages in general differentiate, proliferate and undergo apoptosis at the inflammatory site. Frequently two subtypes of macrophages M1 and M2 has to act crucially in balancing the micro-environmental conditions of endothelial cells in arteries. The productions of proinflammatory mediators like IL-1, IL-6, TNF-α by M1 macrophage has atherogenic properties majorly produced during the early progression of atherosclerotic plaques. To counteract cytokine productions and M1-M2 balance, secondary metabolites (phytochemicals) from plants act as a therapeutic agent in alleviating atherosclerosis progression. This review summarizes the fundamental role of the macrophage in atherosclerotic lesion formation along with its plasticity characteristic as well as recent therapeutic strategies using herbal components and anti-inflammatory cytokines as potential immunomodulators.

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