Protein mobilities and P-selectin storage in Weibel-Palade bodies.

Science.gov (United States)

Kiskin, Nikolai I; Hellen, Nicola; Babich, Victor; Hewlett, Lindsay; Knipe, Laura; Hannah, Matthew J; Carter, Tom

2010-09-01

Using fluorescence recovery after photobleaching (FRAP) we measured the mobilities of EGFP-tagged soluble secretory proteins in the endoplasmic reticulum (ER) and in individual Weibel-Palade bodies (WPBs) at early (immature) and late (mature) stages in their biogenesis. Membrane proteins (P-selectin, CD63, Rab27a) were also studied in individual WPBs. In the ER, soluble secretory proteins were mobile; however, following insertion into immature WPBs larger molecules (VWF, Proregion, tPA) and P-selectin became immobilised, whereas small proteins (ssEGFP, eotaxin-3) became less mobile. WPB maturation led to further decreases in mobility of small proteins and CD63. Acute alkalinisation of mature WPBs selectively increased the mobilities of small soluble proteins without affecting larger molecules and the membrane proteins. Disruption of the Proregion-VWF paracrystalline core by prolonged incubation with NH(4)Cl rendered P-selectin mobile while VWF remained immobile. FRAP of P-selectin mutants revealed that immobilisation most probably involves steric entrapment of the P-selectin extracellular domain by the Proregion-VWF paracrystal. Significantly, immobilisation contributed to the enrichment of P-selectin in WPBs; a mutation of P-selectin preventing immobilisation led to a failure of enrichment. Together these data shed new light on the transitions that occur for soluble and membrane proteins following their entry and storage into post-Golgi-regulated secretory organelles.

Platelet aggregation but not activation and degranulation during the acute post-ischemic reperfusion phase in livers with no underlying disease

NARCIS (Netherlands)

van Golen, Rowan F.; Stevens, Katarzyna M.; Colarusso, Pina; Jaeschke, Hartmut; Heger, Michal

2015-01-01

Platelets and P-selectin (CD62P) play an unequivocal role in the pathology of hepatic ischemia/reperfusion (I/R) injury. Inhibition or knock-out of P-selectin or immunodepletion of platelets results in amelioration of post-ischemic inflammation, reduced hepatocellular damage, and improved survival.

Serum Levels of Soluble P-Selectin Are Increased and Associated With Disease Activity in Patients With Behçet's Syndrome

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Yusuf Turkoz

2005-01-01

Full Text Available Behçet's syndrome (BS is a relapsing, chronic, inflammatory disease characterized by endothelial dysfunction, atherothromboembogenesis, and leukocytoclastic vasculitis with complex immunologic molecular interactions. Generalized derangements of the lymphocyte and neutrophil populations, activated monocytes, and increased PMNLs motility with upregulated cell surface molecules such as ICAM-1, VCAM-1, and E-selectin, which are found on the endothelial cells, leukocytes, and platelets, have all been demonstrated during the course of BS. Our aim is to investigate the association of serum concentrations of soluble P-selectin in patients with BS, and to evaluate whether disease activity has an effect on their blood levels. This multicenter study included 31 patients with BS (15 men and 16 women and 20 age- and sex-matched healthy control volunteers (11 men and nine women. Neutrophil count, erythrocyte sedimentation rate, and acute-phase reactants as well as soluble P-selectin levels were determined. The mean age and sex distributions were similar (P>.05 between BS patients (35 years and control volunteers (36 years. Serum levels of soluble P-selectin in patients with BS (399 ± 72 ng/mL were significantly (P<.001 higher when compared with control subjects (164±40   ng/mL. In addition, active BS patients (453±37 ng/mL had significantly (P<.001 elevated levels of soluble P-selectin than those in inactive period (341±52 ng/mL. This study clearly demonstrated that serum soluble P-selectin levels are increased in BS patients when compared with control subjects, suggesting a modulator role for soluble P-selectin during the course of platelet activation and therefore, atherothrombogenesis formation in BS, especially in active disease.

Not just a marker: CD34 on human hematopoietic stem/progenitor cells dominates vascular selectin binding along with CD44

KAUST Repository

Abu Samra, Dina Bashir Kamil; Aleisa, Fajr A; Al-Amoodi, Asma S.; Jalal Ahmed, Heba M.; Chin, Chee Jia; AbuElela, Ayman; Bergam, Ptissam; Sougrat, Rachid; Merzaban, Jasmeen

2017-01-01

CD34 is routinely used to identify and isolate human hematopoietic stem/progenitor cells (HSPCs) for use clinically in bone marrow transplantation, but its function on these cells remains elusive. Glycoprotein ligands on HSPCs help guide their migration to specialized microvascular beds in the bone marrow that express vascular selectins (E- and P-selectin). Here, we show that HSPC-enriched fractions from human hematopoietic tissue expressing CD34 (CD34pos) bound selectins, whereas those lacking CD34 (CD34neg) did not. An unbiased proteomics screen identified potential glycoprotein ligands on CD34pos cells revealing CD34 itself as a major vascular selectin ligand. Biochemical and CD34 knockdown analyses highlight a key role for CD34 in the first prerequisite step of cell migration, suggesting that it is not just a marker on these cells. Our results also entice future potential strategies to investigate the glycoforms of CD34 that discriminate normal HSPCs from leukemic cells and to manipulate CD34neg HSPC-enriched bone marrow or cord blood populations as a source of stem cells for clinical use.

Not just a marker: CD34 on human hematopoietic stem/progenitor cells dominates vascular selectin binding along with CD44

KAUST Repository

Abu Samra, Dina Bashir Kamil

2017-12-27

CD34 is routinely used to identify and isolate human hematopoietic stem/progenitor cells (HSPCs) for use clinically in bone marrow transplantation, but its function on these cells remains elusive. Glycoprotein ligands on HSPCs help guide their migration to specialized microvascular beds in the bone marrow that express vascular selectins (E- and P-selectin). Here, we show that HSPC-enriched fractions from human hematopoietic tissue expressing CD34 (CD34pos) bound selectins, whereas those lacking CD34 (CD34neg) did not. An unbiased proteomics screen identified potential glycoprotein ligands on CD34pos cells revealing CD34 itself as a major vascular selectin ligand. Biochemical and CD34 knockdown analyses highlight a key role for CD34 in the first prerequisite step of cell migration, suggesting that it is not just a marker on these cells. Our results also entice future potential strategies to investigate the glycoforms of CD34 that discriminate normal HSPCs from leukemic cells and to manipulate CD34neg HSPC-enriched bone marrow or cord blood populations as a source of stem cells for clinical use.

Platelet degranulation and monocyte-platelet complex formation are increased in the acute and convalescent phases after ischaemic stroke or transient ischaemic attack.

LENUS (Irish Health Repository)

McCabe, Dominick J H

2004-06-01

Flow cytometric studies suggest that platelets are activated in ischaemic stroke or transient ischaemic attack (TIA). However, few studies have measured circulating leucocyte-platelet complexes in this patient population. Whole blood flow cytometry was used to quantify the expression of CD62P-, CD63-, and PAC1-binding, and the percentages of leucocyte-platelet complexes in acute (1-27 d, n = 79) and convalescent (79-725 d, n = 70) ischaemic cerebrovascular disease (CVD) patients compared with controls without CVD (n = 27). We performed a full blood count, and measured plasma levels of soluble P-selectin, soluble E-selectin, and von Willebrand factor antigen (VWF:Ag) as additional markers of platelet and\\/or endothelial cell activation. The median percentage CD62P expression and the median percentage monocyte-platelet complexes were higher in both acute and convalescent CVD patients than controls (P <\\/= 0.02). The mean white cell count and mean VWF:Ag levels were significantly elevated in the acute and convalescent phases after ischaemic stroke or TIA (P <\\/= 0.02). Otherwise, there was no significant increase in any other marker of platelet or endothelial activation in CVD patients. There was a positive correlation between the percentage expression of CD62P and the percentages of both neutrophil-platelet and monocyte-platelet complexes in the acute phase, and the percentages of all leucocyte-platelet complexes in the convalescent phase after ischaemic CVD. This study provides evidence for ongoing excessive platelet and\\/or endothelial activation in ischaemic CVD patients despite treatment with antithrombotic therapy.

Soluble CD40 ligand stimulates CD40-dependent activation of the β2 integrin Mac-1 and protein kinase C zeda (PKCζ in neutrophils: implications for neutrophil-platelet interactions and neutrophil oxidative burst.

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Rong Jin

Full Text Available Recent work has revealed an essential involvement of soluble CD40L (sCD40L in inflammation and vascular disease. Activated platelets are the major source of sCD40L, which has been implicated in platelet and leukocyte activation, although its exact functional impact on leukocyte-platelet interactions and the underlying mechanisms remain undefined. We aimed to determine the impact and the mechanisms of sCD40L on neutrophils. We studied neutrophil interactions with activated, surface-adherent platelets as a model for leukocyte recruitment to the sites of injury. Our data show that CD40L contributes to neutrophil firm adhesion to and transmigration across activated surface-adherent platelets, possibly through two potential mechanisms. One involves the direct interaction of ligand-receptor (CD40L-CD40, i.e., platelet surface CD40L interaction with neutrophil CD40; another involves an indirect mechanism, i.e. soluble CD40L stimulates activation of the leukocyte-specific β2 integrin Mac-1 in neutrophils and thereby further promotes neutrophil adhesion and migration. Activation of the integrin Mac-1 is known to be critical for mediating neutrophil adhesion and migration. sCD40L activated Mac-1 in neutrophils and enhanced neutrophil-platelet interactions in wild-type neutrophils, but failed to elicit such responses in CD40-deficient neutrophils. Furthermore, our data show that the protein kinase C zeta (PKCζ is critically required for sCD40L-induced Mac-1 activation and neutrophil adhesive function. sCD40L strongly stimulated the focal clustering of Mac-1 (CD11b and the colocalization of Mac-1 with PKCζ in wild-type neutrophils, but had minimal effect in CD40-deficient neutrophils. Blocking PKCζ completely inhibited sCD40L-induced neutrophil firm adhesion. Moreover, sCD40L strongly stimulates neutrophil oxidative burst via CD40-dependent activation of PI3K/NF-KB, but independent of Mac-1 and PKCζ. These findings may contribute to a better

The hemostatic agent ethamsylate promotes platelet/leukocyte aggregate formation in a model of vascular injury.

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Hernandez, Maria Rosa; Alvarez-Guerra, Miriam; Escolar, Ginés; Chiavaroli, Carlo; Hannaert, Patrick; Garay, Ricardo P

2004-08-01

The hemostatic agent ethamsylate enhances membrane expression of P-selectin in human platelets, but whether this promotes platelet-leukocyte aggregate formation is unknown. Here we investigated this point by flow cytometry determination of human platelet-leukocyte aggregates under basal conditions and after whole-blood perfusion through a damaged rabbit aorta segment. Actions of ethamsylate on adhesive molecules of platelets and leukocytes were investigated in parallel. Under basal conditions, ethamsylate was unable to modify whole-blood platelet-leukocyte aggregation, but following whole-blood perfusion through a damaged vessel, ethamsylate produced a modest, but significant increase in platelet-leukocyte aggregates (48+/-21 and 45+/-26% above control levels at ethamsylate 20 and 40 microm respectively). In isolated leukocyte plasma membranes, 14C-ethamsylate specifically bound up to an amount of 660 pmol/mg protein. Moreover, at concentrations > or =1 microm, ethamsylate induced an important (100-200%) and significant increase in the P-selectin glycoprotein ligand 1 (PSGL-1) fluorescence signal in isolated leukocytes and was unable to significantly modify the percentage of CD11b-positive cells. However, no significant changes in aggregate formation were found when ethamsylate was incubated with isolated leukocytes and blood was reconstituted and perfused. In isolated platelet cell membranes, anti-P-selectin antibody and the anti-integrin RGD-containing pentapeptide (GRDGS) were unable to displace 14C-ethamsylate binding. In conclusion, ethamsylate specifically binds to plasma membranes of leukocytes, enhances membrane PSGL-1 expression and promotes leukocyte-platelet aggregation in whole-blood perfused through a damaged vascular segment. These results together with the previously observed enhancement of platelet P-selectin membrane expression [Thromb. Res. (2002)107:329-335] confirms and extends the view that ethamsylate acts on the first step of hemostasis, by

DEFINITION OF ACTIVATED THROMBOCYTE NUMBER WITH ANTIBODIES FOR ACTIVATED FIBRINOGEN AND P-SELECTIN IN PATIENTS WITH ESSENTIAL THROMBOCYTHEMIA AND ANTIAGGREGATION DRUG EFFECT

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Samo Zver

2004-12-01

Full Text Available Background. Essential thrombocythemia (ET is a chronic myeloproliferative disease with a platelet count within the range of 400–2000 × 109/L. Higher percentage of platelets in the circulation of patients with ET express also activation markers on their membranes. Two of such markers are P-selectin and activated fibrinogen on platelet membranes. Because of frequent thrombembolic and also bleeding related complications, treatment of ET is mandatory. Patients whose platelet count is less than 1000 × 109/L and who did not suffer any thrombembolic complication during the course of the disease, are ussually treated with an antiaggregation drug, acetylsalicylic acid 100 mg/daily orally. Clopidogrel is an adenosyn-di-phosphate (ADP receptor antagonist in platelets. There is no routine clinical data about clopidogrel treatment in the patients with ET and only sporadic case reports can be find in the literature.Patients and methods. In our clinical study we compared antiaggregational effects of acetylsalicylic acid and clopidogrel, by measuring the P-selectin level and activated fibrinogen expression on platelet membranes.There were 35 ET patients included, within the age range between 21 and 78 years and with platelet counts within 451–952 × 109/L. None of the patients did suffer any thrombembolic complication during the course of the disease. During the sequential 14 day periods, patients received acetylsalicylic acid 100 mg/daily orally, followed by clopidogrel 75 mg/daily orally and ultimativelly, together acetylsalicylic acid 100 mg/daily orally plus clopidogrel 75 mg/daily orally. After each fourteen days period the level of P-selectin and activated fibrinogen activated platelets were determined with monoclonal antibodies on flow cytometer. Statistical evaluation was calculated on the difference of average values between the two small, independent pair groups with the t-test.Results. When the patients stopped with acetylsalicylic acid and

The value of flow cytometric analysis of platelet glycoprotein expression of CD34+ cells measured under conditions that prevent P-selectin-mediated binding of platelets

NARCIS (Netherlands)

Dercksen, M. W.; Weimar, I. S.; Richel, D. J.; Breton-Gorius, J.; Vainchenker, W.; Slaper-Cortenbach, C. M.; Pinedo, H. M.; von dem Borne, A. E.; Gerritsen, W. R.; van der Schoot, C. E.

1995-01-01

In the present study, we show by adhesion assays and ultrastructural studies that platelets can bind to CD34+ cells from human blood and bone marrow and that this interaction interferes with the accurate detection of endogenously expressed platelet glycoproteins (GPs). The interaction between these

Equid herpesvirus type 1 activates platelets.

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Tracy Stokol

Full Text Available Equid herpesvirus type 1 (EHV-1 causes outbreaks of abortion and neurological disease in horses. One of the main causes of these clinical syndromes is thrombosis in placental and spinal cord vessels, however the mechanism for thrombus formation is unknown. Platelets form part of the thrombus and amplify and propagate thrombin generation. Here, we tested the hypothesis that EHV-1 activates platelets. We found that two EHV-1 strains, RacL11 and Ab4 at 0.5 or higher plaque forming unit/cell, activate platelets within 10 minutes, causing α-granule secretion (surface P-selectin expression and platelet microvesiculation (increased small events double positive for CD41 and Annexin V. Microvesiculation was more pronounced with the RacL11 strain. Virus-induced P-selectin expression required plasma and 1.0 mM exogenous calcium. P-selectin expression was abolished and microvesiculation was significantly reduced in factor VII- or X-deficient human plasma. Both P-selectin expression and microvesiculation were re-established in factor VII-deficient human plasma with added purified human factor VIIa (1 nM. A glycoprotein C-deficient mutant of the Ab4 strain activated platelets as effectively as non-mutated Ab4. P-selectin expression was abolished and microvesiculation was significantly reduced by preincubation of virus with a goat polyclonal anti-rabbit tissue factor antibody. Infectious virus could be retrieved from washed EHV-1-exposed platelets, suggesting a direct platelet-virus interaction. Our results indicate that EHV-1 activates equine platelets and that α-granule secretion is a consequence of virus-associated tissue factor triggering factor X activation and thrombin generation. Microvesiculation was only partly tissue factor and thrombin-dependent, suggesting the virus causes microvesiculation through other mechanisms, potentially through direct binding. These findings suggest that EHV-1-induced platelet activation could contribute to the thrombosis

P-selectin- and heparanase-dependent antimetastatic activity of non-anticoagulant heparins.

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Hostettler, Nina; Naggi, Annamaria; Torri, Giangiacomo; Ishai-Michaeli, Riva; Casu, Benito; Vlodavsky, Israel; Borsig, Lubor

2007-11-01

Vascular cell adhesion molecules, P- and L-selectins, facilitate metastasis of cancer cells in mice by mediating interactions with platelets, endothelium, and leukocytes. Heparanase is an endoglycosidase that degrades heparan sulfate of extracellular matrix, thereby promoting tumor invasion and metastasis. Heparin is known to efficiently attenuate metastasis in different tumor models. Here we identified modified, nonanticoagulant species of heparin that specifically inhibit selectin-mediated cell-cell interactions, heparanase enzymatic activity, or both. We show that selective inhibition of selectin interactions or heparanase with specific heparin derivatives in mouse models of MC-38 colon carcinoma and B16-BL6 melanoma attenuates metastasis. Selectin-specific heparin derivatives attenuated metastasis of MC-38 carcinoma, but heparanase-specific derivatives had no effect, in accordance with the virtual absence of heparanase activity in these cells. Heparin derivatives had no further effect on metastasis in mice deficient in P- and L-selectin, indicating that selectins are the primary targets of heparin antimetastatic activity. Selectin-specific and heparanase-specific derivatives attenuated metastasis of B16-BL6 melanomas to a similar extent. When mice were injected with a derivative containing both heparanase and selectin inhibitory activity, no additional attenuation of metastasis could be observed. Thus, selectin-specific heparin derivatives efficiently attenuated metastasis of both tumor cell types whereas inhibition of heparanase led to reduction of metastasis only in tumor cells producing heparanase.

Raised soluble P-selectin moderately accelerates atherosclerotic plaque progression.

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Kevin J Woollard

Full Text Available Soluble P-selectin (sP-selectin, a biomarker of inflammatory related pathologies including cardiovascular and peripheral vascular diseases, also has pro-atherosclerotic effects including the ability to increase leukocyte recruitment and modulate thrombotic responses in vivo. The current study explores its role in progressing atherosclerotic plaque disease. Apoe-/- mice placed on a high fat diet (HFD were given daily injections of recombinant dimeric murine P-selectin (22.5 µg/kg/day for 8 or 16 weeks. Saline or sE-selectin injections were used as negative controls. In order to assess the role of sP-selectin on atherothrombosis an experimental plaque remodelling murine model, with sm22α-hDTR Apoe-/- mice on a HFD in conjunction with delivery of diphtheria toxin to induce targeted vascular smooth muscle apoptosis, was used. These mice were similarly given daily injections of sP-selectin for 8 or 16 weeks. While plaque mass and aortic lipid content did not change with sP-selectin treatment in Apoe-/- or SM22α-hDTR Apoe-/- mice on HFD, increased plasma MCP-1 and a higher plaque CD45 content in Apoe-/- HFD mice was observed. As well, a significant shift towards a more unstable plaque phenotype in the SM22α-hDTR Apoe-/- HFD mice, with increased macrophage accumulation and lower collagen content, leading to a lower plaque stability index, was observed. These results demonstrate that chronically raised sP-selectin favours progression of an unstable atherosclerotic plaque phenotype.

An Analysis of Trafficking Receptors Shows that CD44 and P-Selectin Glycoprotein Ligand-1 Collectively Control the Migration of Activated Human T-Cells

KAUST Repository

Ali, Amal J.; AbuElela, Ayman; Merzaban, Jasmeen

2017-01-01

-selectin ligands, to CD44, a ligand that has not previously been characterized as an E-selectin ligand on activated human T-cells. We showed that CD44 acts as a functional E-selectin ligand when expressed on both CD4+ and CD8+ T-cells. Moreover, the CD44 protein

Mechanisms of the priming effect of low doses of lipopoly-saccharides on leukocyte-dependent platelet aggregation in whole blood.

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Montrucchio, Giuseppe; Bosco, Ornella; Del Sorbo, Lorenzo; Fascio Pecetto, Paolo; Lupia, Enrico; Goffi, Alberto; Omedè, Paola; Emanuelli, Giorgio; Camussi, Giovanni

2003-11-01

Several studies focused on the ability of bacterial lipopolysac-charides (LPS) in triggering platelet and/or leukocyte activation. The aim of this study was to investigate the molecular mechanisms involved in the aggregation of platelets and in their interaction with leukocytes in whole blood after stimulation with low doses of LPS. LPS did not directly induce platelet aggregation in whole blood, but they primed the aggregation of platelets induced by epinephrine, adenosine diphosphate and arachidonic acid. As shown by cytofluorimetry, platelets neither bind FITC-LPS, nor express the LPS-receptors CD14 and toll-like receptor 4 (TLR4). On the contrary, LPS primed monocytes and to a lesser extent polymorphonuclear neutrophils to adhere to platelets. Both platelet-leukocyte interaction and platelet aggregation in whole blood were inhibited by blockade of CD14 and TLR4. Moreover, the interaction between platelets and leukocytes was inhibited by P-selectin, and by blockade of PAF and reactive oxygen species, suggesting a role of P-selectin and of leukocyte-derived mediators. In conclusion, these results elucidate the mechanisms leading to platelet activation and interaction with leukocytes triggered by LPS. They suggest that the activation of platelets by LPS is mainly dependent on leukocytes and especially monocytes as a result of CD14 and TLR4 engagement. Moreover, we found that leukocyte-platelet interaction was triggered by the synthesis of PAF and the generation of oxygen radicals that induced upregulation of surface expression of P-selectin.

Complete identification of E-selectin ligands on neutrophils reveals distinct functions of PSGL-1, ESL-1, and CD44.

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Hidalgo, Andrés; Peired, Anna J; Wild, Martin; Vestweber, Dietmar; Frenette, Paul S

2007-04-01

The selectins and their ligands are required for leukocyte extravasation during inflammation. Several glycoproteins have been suggested to bind to E-selectin in vitro, but the complete identification of its physiological ligands has remained elusive. Here, we showed that E-selectin ligand-1 (ESL-1), P-selectin glycoprotein ligand-1 (PSGL-1), and CD44 encompassed all endothelial-selectin ligand activity on neutrophils by using gene- and RNA-targeted loss of function. PSGL-1 played a major role in the initial leukocyte capture, whereas ESL-1 was critical for converting initial tethers into steady slow rolling. CD44 controlled rolling velocity and mediated E-selectin-dependent redistribution of PSGL-1 and L-selectin to a major pole on slowly rolling leukocytes through p38 signaling. These results suggest distinct and dynamic contributions of these three glycoproteins in selectin-mediated neutrophil adhesion and signaling.

Sulfated Hexasaccharides Attenuate Metastasis by Inhibition of P-selectin and Heparanase

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Lubor Borsig

2011-05-01

Full Text Available Development of compounds that target both heparanase and selectins is emerging as a promising approach for cancer therapy. Selectins are vascular cell adhesion molecules that mediate tumor cell interactions with platelets, leukocytes, and the vascular endothelium. Heparanase is an endoglycosidase that degrades heparan sulfate in the tumor microenvironment, cell surfaces, and vessel wall. Acting together, these molecules facilitate tumor cell arrest, extravasation, and metastasis. Here, we report the preparation of novel semisynthetic sulfated tri mannose C-C-linked dimers (STMCs endowed with heparanase and selectin inhibitory activity. The P-selectin specificity of the STMC was defined by the anomeric linkage of the C-C bond. This STMC hexasaccharide is an effective inhibitor of P-selectin in vivo. We show that selective inhibition of heparanase attenuates metastasis in B16-BL6 melanoma cells, expressing high levels of this endoglycosidase, but has no effect on the metastasis of MC-38 carcinoma cells that express little or no heparanase activity. P-selectin-specific STMC attenuated metastasis in both animal models, indicating that inhibition of tumor cell interaction with the vascular endothelium is critical for cancer dissemination. Thus, the small size, the stability of the C-C bond, and the chemically defined structure of the newly generated STMCs make them superior to heparin derivatives and signify STMCs as valuable candidates for further evaluation.

Combined aspirin and cilostazol treatment is associated with reduced platelet aggregation and prevention of exercise-induced platelet activation.

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Cleanthis, M; Bhattacharya, V; Smout, J; Ashour, H; Stansby, G

2009-05-01

Cilostazol has proven efficacy in increasing walking distance in claudicants, but it has not been demonstrated to be more effective than placebo in secondary cardiovascular prevention. The direct effect of exercise on platelet function remains less well defined. We have investigated the effect of combination treatment with aspirin and cilostazol on platelet activity in claudicants subjected to repeated treadmill exercise. Nineteen claudicants completed a double-blind, randomised, controlled, cross-over trial. Each subject received a 2-week course of aspirin (75mg) and placebo and aspirin and cilostazol (100mg twice daily). Following each 2-week treatment period, patients participated in a standardised treadmill test (3.2kmh(-1), 10 degrees incline) walking to maximal claudication distance. The exercise was repeated thrice in total, and blood was sampled before and after exercise. Platelet activation was measured using free platelet counting aggregation, flow cytometry for surface markers of platelet activation and soluble P-selectin assay. Compared to aspirin and placebo, combination treatment with aspirin and cilostazol was associated with reduced arachidonic-acid-induced platelet aggregation (pWilcoxon signed-rank test). Aspirin and placebo treatment were associated with elevated P-selectin expression, platelet-monocyte aggregation and reduced CD42b expression (pWilcoxon signed-rank test) post-exercise. No difference was seen in spontaneous platelet aggregation whilst soluble P-selectin was reduced post-exercise with combination treatment with aspirin and cilostazol (pWilcoxon signed-rank test). Combination treatment with aspirin and cilostazol results in suppression of platelet activation and reduces the effect of exercise on platelets. The benefit seen may be a result of cilostazol enhancing the inhibitory effect of aspirin on the cyclo-oxygenase pathway.

Increased concentrations of soluble CD40 ligand platelet in patients with primary antiphospholipidic syndrome.

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Galicia López, Aida; Olguín Ortega, Lourdes; Saavedra, Miguel A; Méndez Cruz, René; Jimenez Flores, Rafael; García de la Peña, Maximiliano

2013-01-01

To determine the concentrations of sCD40L in patients with PAPS, and establish its association with the number of thrombosis. We included patients with PAPS and healthy controls of the same age and sex. For analysis, patients with PAPS were divided into 2 groups: 1) patients with 1 thrombosis, and 2) patients with >1 thrombosis. Soluble CD40L concentrations were determined by ELISA method. sCD40L concentrations were significantly higher in patients with PAPS compared with the controls (9.72 ng ± 11.23 ng/ml vs. 4.69 ± 4.04 ng/ml) (P=.04) There was no association between serum levels of sCD40L and the number of thrombosis (1 thrombosis: 9.81 ± 9.87 ng/ml vs 9.63 ± 12.75 ng/ml in ≥ 1thrombosis (P=.13). In women with pregnancy and abortions, (13 patients) concentrations of sCD40L were higher than in those patients without a history of abortion (26 patients) but without statically significant difference (12.11 ± 16.46 ng/ml vs. 8.80 ± 8.61 ng/ml) (P=.33). There was no correlation between levels of sCD40L and the total number of thrombosis. Patients with PAPS have higher concentrations of sCD40L compared with healthy subjects, although this is not associated with a greater number of thrombosis. Among patients with PAPS, there is a tendency to higher concentrations of sCD40L in women with pregnancy and history of abortion. Since the platelet is the main cellular source of sCD40L, is possible that this pathway plays a pathogenic role in patients with PAPS. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Serum Levels of Platelet Released CD40 Ligand Are Increased in Early Onset Occlusive Carotid Artery Disease

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József Balla

2006-01-01

Full Text Available Objective: Soluble CD40 ligand (sCD40L has been suggested as a key mediator between inflammation and atherosclerosis, and the CD40-CD40L interaction has a role in atherosclerotic lesion progression. We evaluated if platelet released serum sCD40L and sCD40 levels differ between patients with early onset occlusive carotid artery disease and age-matched controls.

The effect of centrifugation speed and time on pre-analytical platelet activation.

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Söderström, Anna C; Nybo, Mads; Nielsen, Christian; Vinholt, Pernille J

2016-12-01

The results of laboratory analyses are affected by pre-analytical variables, and in particular can platelets be activated by shear handling stress and secrete granular substances. We therefore evaluated the effect of centrifugation speed and time on pre-analytical platelet activation. Citrate- and EDTA-anticoagulated blood from healthy volunteers were centrifuged at 80-10,000 g for 5-15 min to prepare plasma and platelet-rich plasma. Pre-analytical platelet activation was assessed by flow cytometric measurement of platelet P-selectin (CD62p) expression. Blood cell counts, mean platelet volume (MPV), immature platelet fraction (IPF), and platelet distribution width (PDW) were measured. Platelet aggregation in platelet-rich plasma induced by arachidonic acid (AA), ADP or thrombin receptor activator peptide-6 (TRAP) was tested by 96-well aggregometry. The median percentage of platelets expressing P-selectin in citrate- and EDTA-plasma centrifuged at 2000 g for 10 min were 43% [interquartile range (IQR), 38%-53%] and 56% (IQR, 31%-78%), respectively (p=0.82). Platelet-rich plasma prepared at 100-250 g for 10 min had significantly lower platelet P-selectin expression (11%-15%), pcentrifuged. In platelet-rich plasma, increasing centrifugation speed significantly increased platelet yield but decreased contamination from other blood cells, platelet composition was altered as platelet parameters (MPV, IPF, and PDW) was lowered. Platelet aggregation was not affected by the centrifugation speed platelet-rich plasma was prepared. Proportional to centrifugation speed, platelets in plasma and platelet-rich plasma were activated with centrifugation speed, cell content and composition changed while platelet aggregation was unaltered.

Flow cytometric analysis reveals the high levels of platelet activation parameters in circulation of multiple sclerosis patients.

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Morel, Agnieszka; Rywaniak, Joanna; Bijak, Michał; Miller, Elżbieta; Niwald, Marta; Saluk, Joanna

2017-06-01

The epidemiological studies confirm an increased risk of cardiovascular disease in multiple sclerosis, especially prothrombotic events directly associated with abnormal platelet activity. The aim of our study was to investigate the level of blood platelet activation in the circulation of patients with chronic phase of multiple sclerosis (SP MS) and their reactivity in response to typical platelets' physiological agonists. We examined 85 SP MS patients diagnosed according to the revised McDonald's criteria and 50 healthy volunteers as a control group. The platelet activation and reactivity were assessed using flow cytometry analysis of the following: P-selectin expression (CD62P), activation of GP IIb/IIIa complex (PAC-1 binding), and formation of platelet microparticles (PMPs) and platelet aggregates (PA) in agonist-stimulated (ADP, collagen) and unstimulated whole blood samples. Furthermore, we measured the level of soluble P-selectin (sP-selectin) in plasma using ELISA method, to evaluate the in vivo level of platelet activation, both in healthy and SP MS subjects. We found a statistically significant increase in P-selectin expression, GP IIb/IIIa activation, and formation of PMPs and PA, as well as in unstimulated and agonist-stimulated (ADP, collagen) platelets in whole blood samples from patients with SP MS in comparison to the control group. We also determined the higher sP-selectin level in plasma of SP MS subjects than in the control group. Based on the obtained results, we might conclude that during the course of SP MS platelets are chronically activated and display hyperreactivity to physiological agonists, such as ADP or collagen.

Aqueous extract of Rabdosia rubescens leaves: forming nanoparticles, targeting P-selectin, and inhibiting thrombosis

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Wang Y

2015-11-01

Full Text Available Yuji Wang,1 Jingcheng Tang,1 Haimei Zhu,1 Xueyun Jiang,1 Jiawang Liu,1 Wenyun Xu,1 Haiping Ma,1 Qiqi Feng,1 Jianhui Wu,1 Ming Zhao,1,2 Shiqi Peng1 1Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Endogenous Prophylactic of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, College of Pharmaceutical Sciences, Capital Medical University, Beijing, People’s Republic of China; 2Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan Abstract: The hot water extract of Rabdosia rubescens was traditionally used as an antithrombotic medicine. To explore its antithrombotic utility and mechanism, we carried out a series of in vitro and in vivo assays in this study. In vitro platelet aggregation assay showed that the half maximal inhibitory concentration values of aqueous extract of R. rubescens leaves (AERL inhibiting platelet aggregation induced by thrombin, arachidonic acid, adenosine diphosphate, and platelet-activating factor ranged from 0.12 mg/mL to 1.43 mg/mL. The minimal effective oral dose of AERL inhibiting the rats from forming thrombus was 25 mg/kg. Both in vitro and in vivo actions were correlated with AERL concentration-dependently inhibiting sP-selectin release. In water, AERL formed nanoparticles, and their size depended on the concentration. Docking the five nucleotides, 21 phenolic acids, and four diterpenoids identified by high-performance liquid chromatography–photodiode array detector/(-electrospray ionization-tandem mass spectrometry analysis into the active site of P-selectin, rosmarinic acid was predicted to be the antithrombotic ingredient of AERL. In flow cytometry analysis, 1 µM of rosmarinic acid effectively inhibited sP-selectin release in arachidonic acid-activated platelets. In a rat model, 5 mg/kg of oral rosmarinic acid effectively inhibited thrombosis. Keywords: R. rubescens, sP-selectin

Sulfated Hexasaccharides Attenuate Metastasis by Inhibition of P-selectin and Heparanase1

Science.gov (United States)

Borsig, Lubor; Vlodavsky, Israel; Ishai-Michaeli, Rivka; Torri, Giangiacomo; Vismara, Elena

2011-01-01

Development of compounds that target both heparanase and selectins is emerging as a promising approach for cancer therapy. Selectins are vascular cell adhesion molecules that mediate tumor cell interactions with platelets, leukocytes, and the vascular endothelium. Heparanase is an endoglycosidase that degrades heparan sulfate in the tumor microenvironment, cell surfaces, and vessel wall. Acting together, these molecules facilitate tumor cell arrest, extravasation, and metastasis. Here, we report the preparation of novel semisynthetic sulfated tri mannose C-C-linked dimers (STMCs) endowed with heparanase and selectin inhibitory activity. The P-selectin specificity of the STMC was defined by the anomeric linkage of the C-C bond. This STMC hexasaccharide is an effective inhibitor of P-selectin in vivo. We show that selective inhibition of heparanase attenuates metastasis in B16-BL6 melanoma cells, expressing high levels of this endoglycosidase, but has no effect on the metastasis of MC-38 carcinoma cells that express little or no heparanase activity. P-selectin-specific STMC attenuated metastasis in both animal models, indicating that inhibition of tumor cell interaction with the vascular endothelium is critical for cancer dissemination. Thus, the small size, the stability of the C-C bond, and the chemically defined structure of the newly generated STMCs make them superior to heparin derivatives and signify STMCs as valuable candidates for further evaluation. PMID:21532885

Treatment with a histone deacetylase inhibitor, valproic acid, is associated with increased platelet activation in a large animal model of traumatic brain injury and hemorrhagic shock

DEFF Research Database (Denmark)

Dekker, Simone E; Sillesen, Martin; Bambakidis, Ted

2014-01-01

synergistic benefits. In this study, we hypothesized that VPA administration would be associated with a conservation of platelet function as measured by increased platelet activation after resuscitation. MATERIALS AND METHODS: Ten swine (42-50 kg) were subjected to TBI and HS (40% blood loss). Animals were...... neuroprotective effects of VPA may be due to a conservation of platelet function as measured by a higher platelet activation response after resuscitation....... left in shock for 2 h before resuscitation with either FFP or FFP + VPA (300 mg/kg). Serum levels of platelet activation markers transforming growth factor beta, CD40 L, P-selectin, and platelet endothelial cell adhesion molecule (PECAM) 1 were measured at baseline, postresuscitation, and after a 6-h...

Effect of thrombopoietin receptor agonists on markers of coagulation and P-selectin in patients with immune thrombocytopenia

DEFF Research Database (Denmark)

Garabet, Lamya; Ghanima, Waleed; Monceyron Jonassen, Christine

2018-01-01

patients in cohort 1. Significantly higher levels of F1+2, D-dimer, and PAI-1 were found in ITP patients before TPO-RA treatment and in patients on long-term TPO-RA treatment than in controls. Pre-treatment levels of sP-selectin did not differ from controls. Analysis of longitudinal trends showed...... an increase in platelet count, sP-selectin, and PAI-1 after initiation of TPO-RA, followed by gradual decline. Platelet count and sP-selectin remained at higher levels throughout the study, whereas PAI-1 did not. Levels of other studied parameters did not show significant changes after initiation of treatment....... Expression of SELP was up-regulated after initiation of TPO-RA, while the expression of SERPINE1 showed no significant changes. In conclusion, elevated pre-treatment levels of F1+2, D-dimer and PAI-1 are compatible with ITP being an intrinsically pro-thrombotic condition. After TPO-RA treatment, there were...

Inhibition of PAF-induced expression of CD11b and shedding of L-selectin on human neutrophils and eosinophils by the type IV selective PDE inhibitor, rolipram

NARCIS (Netherlands)

Dijkhuizen, B; deMonchy, JGR; Dubois, AEJ; Gerritsen, J; Kauffman, HF

We quantitatively determined whether the selective phosphodiesterase (PDE) inhibitor, rolipram, inhibits changes in the adhesion molecules CD11b and L-selectin on platelet-activating factor (PAF)-stimulated human neutrophils and eosinophils in vitro. Incubations were performed in human whole blood

Platelet storage lesion in interim platelet unit concentrates: A comparison with buffy-coat and apheresis concentrates.

Science.gov (United States)

Singh, Sukhi; Shams Hakimi, Caroline; Jeppsson, Anders; Hesse, Camilla

2017-12-01

Platelet storage lesion is characterized by morphological changes and impaired platelet function. The collection method and storage medium may influence the magnitude of the storage lesion. The aim of this study was to compare the newly introduced interim platelet unit (IPU) platelet concentrates (PCs) (additive solution SSP+, 40% residual plasma content) with the more established buffy-coat PCs (SSP, 20% residual plasma content) and apheresis PCs (autologous plasma) in terms of platelet storage lesions. Thirty PCs (n=10 for each type) were assessed by measuring metabolic parameters (lactate, glucose, and pH), platelet activation markers, and in vitro platelet aggregability on days 1, 4, and 7 after donation. The expression of platelet activation markers CD62p (P-selectin), CD63 (LAMP-3), and phosphatidylserine was measured using flow cytometry and in vitro aggregability was measured with multiple electrode aggregometry. Higher platelet activation and lower in vitro aggregability was observed in IPU than in buffy-coat PCs on day 1 after donation. In contrast, metabolic parameters, expression of platelet activation markers, and in vitro aggregability were better maintained in IPU than in buffy-coat PCs at the end of the storage period. Compared to apheresis PCs, IPU PCs had higher expression of activation markers and lower in vitro aggregability throughout storage. In conclusion, the results indicate that there are significant differences in platelet storage lesions between IPU, buffy-coat, and apheresis PCs. The quality of IPU PCs appears to be at least comparable to buffy-coat preparations. Further studies are required to distinguish the effect of the preparation methods from storage conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in platelet functional parameters and CD62 P expression ...

African Journals Online (AJOL)

EB

Objective: To investigate the changes in platelet functional parameters and CD62 P expression in liver cirrhosis as a possible .... bleeding and non-bleeding group with hepatic cirrhosis (±s). Group ... the body's coagulate function requirement.

Targeting P-selectin glycoprotein ligand-1/P-selectin interactions as a novel therapy for metabolic syndrome.

Science.gov (United States)

Patel, Madhukar S; Miranda-Nieves, David; Chen, Jiaxuan; Haller, Carolyn A; Chaikof, Elliot L

2017-05-01

Obesity-induced insulin resistance and metabolic syndrome continue to pose an important public health challenge worldwide as they significantly increase the risk of type 2 diabetes and atherosclerotic cardiovascular disease. Advances in the pathophysiologic understanding of this process has identified that chronic inflammation plays a pivotal role. In this regard, given that both animal models and human studies have demonstrated that the interaction of P-selectin glycoprotein ligand-1 (PSGL-1) with P-selectin is not only critical for normal immune response but also is upregulated in the setting of metabolic syndrome, PSGL-1/P-selectin interactions provide a novel target for preventing and treating resultant disease. Current approaches of interfering with PSGL-1/P-selectin interactions include targeted antibodies, recombinant immunoglobulins that competitively bind P-selectin, and synthetic molecular therapies. Experimental models as well as clinical trials assessing the role of these modalities in a variety of diseases have continued to contribute to the understanding of PSGL-1/P-selectin interactions and have demonstrated the difficulty in creating clinically relevant therapeutics. Most recently, however, computational simulations have further enhanced our understanding of the structural features of PSGL-1 and related glycomimetics, which are responsible for high-affinity selectin interactions. Leveraging these insights for the design of next generation agents has thus led to development of a promising synthetic method for generating PSGL-1 glycosulfopeptide mimetics for the treatment of metabolic syndrome. Copyright © 2016 Elsevier Inc. All rights reserved.

EMMPRIN (CD147) is a novel receptor for platelet GPVI and mediates platelet rolling via GPVI-EMMPRIN interaction.

Science.gov (United States)

Seizer, Peter; Borst, Oliver; Langer, Harald F; Bültmann, Andreas; Münch, Götz; Herouy, Yared; Stellos, Konstantinos; Krämer, Björn; Bigalke, Boris; Büchele, Berthold; Bachem, Max G; Vestweber, Dietmar; Simmet, Thomas; Gawaz, Meinrad; May, Andreas E

2009-04-01

The Extracellular Matrix Metalloproteinase Inducer (EMMPRIN, CD147, basigin) is an immunoglobulin-like receptor expressed in various cell types. During cellular interactions homotypic EMMPRIN-EMMPRIN interactions are known to induce the synthesis of matrix metalloproteinases. Recently, we have identified EMMPRIN as a novel receptor on platelets. To our knowledge EMMPRIN has not been shown to serve as adhesion receptor, yet. Here we characterise platelet glycoprotein VI (GPVI) as a novel adhesion receptor for EMMPRIN. Human platelets were prestimulated with ADP and perfused over immobilised recombinant EMMPRIN-Fc or Fc-fragments under arterial shear conditions. ADP-stimulated platelets showed significantly enhanced rolling (but not enhanced firm adhesion) on immobilised EMMPRIN-Fc compared to Fc. Pretreatment of platelets with blocking mAbs anti-EMMPRIN or anti-GPVI leads to a significant reduction of rolling platelets on immobilised EMMPRIN-Fc, whereas pretreatment with blocking mAbs anti-p-selectin, anti-alpha4-integrin or anti-GPIIb/IIIa complex (20 microg/ml each) had no effect. Consistently, chinese hamster ovary (CHO) cells stably transfected with GPVI showed enhanced rolling (but not adhesion) on immobilised EMMPRIN-Fc in comparison to non-transfected CHO cells. Similarly, CHO cells stably transfected with EMMPRIN showed enhanced rolling on immobilised GPVI-Fc (or EMMPRIN-Fc) compared to non transfected CHO-cells. Finally, specific binding of EMMPRIN to GPVI was demonstrated by a modified ELISA and surface plasmon resonance technology with a dissociation constant of 88 nM. Platelet GPVI is a novel receptor for EMMPRIN and can mediate platelet rolling via GPVI-EMMPRIN interaction.

Indomethacin induced gastropathy in CD18, intercellular adhesion molecule 1, or P-selectin deficient mice

Science.gov (United States)

Morise, Z; Granger, D; Fuseler, J; Anderson, D; Grisham, M

1999-01-01

BACKGROUND—Neutrophil-endothelial cell interactions are thought to play a critical role in the pathophysiology of non-steroidal anti-inflammatory drug (NSAID) induced gastropathy.
AIMS—To optimise a mouse model of NSAID induced gastropathy and to evaluate the importance of adhesion molecules using adhesion molecule deficient mice.
METHODS—Gastropathy was induced in C57BL/6 mice or their adhesion molecule deficient counterparts via oral administration of indomethacin (20 mg/kg). Lesion scores, mucosal permeability, and histopathology were used to assess gastric mucosal injury.
RESULTS—Intragastric administration of indomethacin induced linear haemorrhagic mucosal lesions, primarily in the corpus of the stomach that were first observed at six hours. These lesions continued to develop over the next six hours with maximal lesion scores and mucosal permeabilities at 12 hours. When indomethacin was administered to mice deficient in CD18, intercellular adhesion molecule 1 (ICAM-1), or P-selectin, there were significant decreases in lesion scores compared with their C57BL/6 controls. In addition, mucosal permeabilities were found to be significantly lower in CD18 or ICAM-1 deficient mice observed at 12 hours.
CONCLUSION—Certain leucocyte and endothelial cell adhesion molecules are important determinants for full expression of indomethacin induced gastropathy. It is proposed that this modification of the mouse model may be useful for the investigation of other pathophysiological mechanisms of NSAID induced gastropathy.


Keywords: indomethacin; gastropathy; cyclooxygenase; intercellular adhesion molecule; VCAM; vascular cell adhesion molecule; P-selectin PMID:10486359

Human SolCD39 Inhibits Injury-induced Development of Neointimal Hyperplasia

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Drosopoulos, Joan H. F.; Kraemer, Rosemary; Shen, Hao; Upmacis, Rita K.; Marcus, Aaron J.; Musi, Elgilda

2010-01-01

SUMMARY Blood platelets provide the initial response to vascular endothelial injury, becoming activated as they adhere to the injured site. Activated platelets recruit leukocytes, and initiate proliferation and migration of vascular smooth muscle cells (SMC) within the injured vessel wall, leading to development of neointimal hyperplasia. Endothelial CD39/NTPDase1 and recombinant solCD39 rapidly metabolize nucleotides, including stimulatory ADP released from activated platelets, thereby suppressing additional platelet reactivity. Using a murine model of vascular endothelial injury, we investigated whether circulating human solCD39 could reduce platelet activation and accumulation, thus abating leukocyte infiltration and neointimal formation following vascular damage. Intraperitoneally-administered solCD39 ADPase activity in plasma peaked 1 hr post-injection, with an elimination half-life of 43 hr. Accordingly, mice were administered solCD39 or saline 1 hr prior to vessel injury, then either sacrificed 24 hr post-injury or treated with solCD39 or saline (3X weekly) for an additional 18 days. 24 hr post-injury, solCD39-treated mice displayed a reduction in platelet activation and recruitment, P-selectin expression, and leukocyte accumulation in the arterial lumen. Furthermore, repeated administration of solCD39 modulated the late stage of vascular injury by suppressing leukocyte deposition, macrophage infiltration and SMC proliferation/migration, resulting in abrogation of neointimal thickening. In contrast, injured femoral arteries of saline-injected mice exhibited massive platelet thrombus formation, marked P-selectin expression, and leukocyte infiltration. Pronounced neointimal growth with macrophage and SMC accretion was also observed (intimal-to-medial area ratio 1.56±0.34 at 19 days). Thus, systemic administration of solCD39 profoundly affects injury-induced cellular responses, minimizing platelet deposition and leukocyte recruitment, and suppressing

Quality of harvested autologous platelets compared with stored donor platelets for use after cardiopulmonary bypass procedures.

Science.gov (United States)

Crowther, M; Ford, I; Jeffrey, R R; Urbaniak, S J; Greaves, M

2000-10-01

Platelet dysfunction has a major contribution in bleeding after cardiopulmonary bypass (CPB) and transfusion of platelets is frequently used to secure haemostasis. Allogeneic platelets prepared for transfusion are functionally impaired. Autologous platelets harvested preoperatively require a shorter storage time before transfusion and their use also avoids the risks associated with transfusion of allogeneic blood products. For the first time, we have compared the functional quality of autologous platelets with allogeneic platelets prepared by two methods, immediately before infusion. Platelet activation was assessed by P-selectin expression and fibrinogen binding using flow cytometry. We also monitored the effects of CPB surgery and re-infusion of autologous platelets on platelet function. Autologous platelet-rich plasma (PRP) contained a significantly lower (P platelets compared with allogeneic platelet preparations, and also contained a significantly higher (P platelets. Allogeneic platelets prepared by donor apheresis were more activated and less responsive than those produced by centrifugation of whole blood. In patients' blood, the percentage of platelets expressing P-selectin or binding fibrinogen increased significantly after CPB (P platelets responsive to in vitro agonists was decreased (P platelet activation during the procedure. The percentage of activated platelets decreased (statistically not significant) after re-infusion of autologous PRP. P-selectin expression had returned to pre-CPB levels 24 h post-operatively. Autologous platelet preparations display minimal activation, but remain responsive. Conservation of platelet function may contribute to the potential clinical benefits of autologous transfusion in cardiopulmonary bypass.

Investigating the feasibility of stem cell enrichment mediated by immobilized selectins.

Science.gov (United States)

Charles, Nichola; Liesveld, Jane L; King, Michael R

2007-01-01

Hematopoietic stem cell therapy is used to treat both malignant and non-malignant diseases, and enrichment of the hematopoietic stem and progenitor cells (HSPCs) has the potential to reduce the likelihood of graft vs host disease or relapse, potentially fatal complications associated with the therapy. Current commercial HSPC isolation technologies rely solely on the CD34 surface marker, and while they have proven to be invaluable, they can be time-consuming with variable recoveries reported. We propose that selectin-mediated enrichment could prove to be a quick and effective method for recovering HSPCs from adult bone marrow (ABM) on the basis of differences in rolling velocities and independently of CD34 expression. Purified CD34+ ABM cells and the unselected CD34- ABM cells were perfused over immobilized P-, E-, and L-selectin-IgG at physiologic wall shear stresses, and rolling velocities and cell retention data were collected. CD34+ ABM cells generally exhibited lower rolling velocities and higher retention than the unselected CD34- ABM cells on all three selectins. For initial CD34+ ABM cell concentrations ranging from 1% to 5%, we predict an increase in purity ranging from 5.2% to 36.1%, depending on the selectin used. Additionally, selectin-mediated cell enrichment is not limited to subsets of cells with inherent differences in rolling velocities. CD34+ KG1a cells and CD34- HL60 cells exhibited nearly identical rolling velocities on immobilized P-selectin-IgG over the entire range of shear stresses studied. However, when anti-CD34 antibody was co-immobilized with the P-selectin-IgG, the rolling velocity of the CD34+ KG1a cells was significantly reduced, making selectin-mediated cell enrichment a feasible option. Optimal cell enrichment in immobilized selectin surfaces can be achieved within 10 min, much faster than most current commercially available systems.

Platelet activation in pregnancy-induced hypertension.

Science.gov (United States)

Karalis, Ioannis; Nadar, Sunil K; Al Yemeni, Eman; Blann, Andrew D; Lip, Gregory Y H

2005-01-01

Although excess platelet activation, as indicated by increased plasma beta thromboglobulin (beta-TG), has been shown in pregnancy-induced hypertension (PIH), platelet adhesion, platelet morphology and a comparison of platelet and soluble (plasma) levels of the adhesion molecules P-selectin (pPsel and sPsel, respectively) have not been studied. We conducted a cross-sectional study of 35 consecutive women with PIH (age 31+/-6 years), 31 consecutive women with normotensive pregnancies (age 29+/-5 years) and 30 normotensive non pregnant women (age 30+/-5 years). Platelet adhesion was studied in vitro by binding to fibrinogen-coated microwells, platelet morphology [mass and volume by flow cytometry], whole-platelet P-selectin (pPsel) by ELISA of the lysate of 2 x 10(8) cells, and the plasma markers soluble P-selectin (sP-sel) and beta-TG, by ELISA. The women with PIH had significantly raised sPsel, pPsel and (as expected) beta-TG (all p<0.05), when compared to the normotensive pregnant women and controls. However, in PIH platelet adhesion was similar to that in the normotensive pregnancy, but still higher than the normal controls (p<0.001). There was no difference among the three groups with respect to platelet mass and volume. pPsel and platelet adhesion correlated with gestational age and with systolic and diastolic blood pressure (all p<0.05). Increased platelet activation and adhesion develop during normal pregnancy, with some indices being further altered in PIH.

Complete identification of E-selectin ligand activity on neutrophils reveals a dynamic interplay and distinct functions of PSGL-1, ESL-1 and CD44

Science.gov (United States)

Wild, Martin; Vestweber, Dietmar; Frenette, Paul S.

2014-01-01

SUMMARY The selectins and their ligands are required for leukocyte extravasation during inflammation. Several glycoproteins have been suggested to bind to E-selectin in vitro but the complete identification of its physiological ligands has remained elusive. Here, we show using gene- and RNA-targeted loss-of-function that E-selectin ligand-1 (ESL-1), PSGL-1 and CD44 encompass all endothelial selectin ligand activity on neutrophils. PSGL-1 plays a major role in the initial leukocyte capture, while ESL-1 is critical to convert initial tethers into steady slow rolling. CD44 controls rolling velocity and mediates E-selectin-dependent redistribution of PSGL-1 and L-selectin to a major pole on slowly rolling leukocytes through p38 signaling. These results suggest distinct and dynamic contributions of these three glycoproteins in selectin-mediated neutrophil adhesion and signaling. PMID:17442598

A functional glycoproteomics approach identifies CD13 as a novel E-selectin ligand in breast cancer.

Science.gov (United States)

Carrascal, M A; Silva, M; Ferreira, J A; Azevedo, R; Ferreira, D; Silva, A M N; Ligeiro, D; Santos, L L; Sackstein, R; Videira, P A

2018-05-17

The glycan moieties sialyl-Lewis-X and/or -A (sLe X/A ) are the primary ligands for E-selectin, regulating subsequent tumor cell extravasation into distant organs. However, the nature of the glycoprotein scaffolds displaying these glycans in breast cancer remains unclear and constitutes the focus of the present investigation. We isolated glycoproteins that bind E-selectin from the CF1_T breast cancer cell line, derived from a patient with ductal carcinoma. Proteins were identified using bottom-up proteomics approach by nanoLC-orbitrap LTQ-MS/MS. Data were curated using bioinformatics tools to highlight clinically relevant glycoproteins, which were validated by flow cytometry, Western blot, immunohistochemistry and in-situ proximity ligation assays in clinical samples. We observed that the CF1_T cell line expressed sLe X , but not sLe A and the E-selectin reactivity was mainly on N-glycans. MS and bioinformatics analysis of the targeted glycoproteins, when narrowed down to the most clinically relevant species in breast cancer, identified CD44 glycoprotein (HCELL) and CD13 as key E-selectin ligands. Additionally, the co-expression of sLe X -CD44 and sLe X -CD13 was confirmed in clinical breast cancer tissue samples. Both CD44 and CD13 glycoforms display sLe X in breast cancer and bind E-selectin, suggesting a key role in metastasis development. Such observations provide a novel molecular rationale for developing targeted therapeutics. While HCELL expression in breast cancer has been previously reported, this is the first study indicating that CD13 functions as an E-selectin ligand in breast cancer. This observation supports previous associations of CD13 with metastasis and draws attention to this glycoprotein as an anti-cancer target. Copyright © 2018 Elsevier B.V. All rights reserved.

Platelets and their chemokines in atherosclerosis – clinical applications

Directory of Open Access Journals (Sweden)

Philipp evon Hundelshausen

2014-08-01

Full Text Available The concept of platelets as important players in the process of atherogenesis has become increasingly accepted due to accumulating experimental and clinical evidence. Despite the progress in understanding the molecular details of atherosclerosis, particularly by using animal models, the inflammatory and thrombotic roles of activated platelet s especially in the human system remain difficult to dissect, as often only the complications of atherosclerosis i.e. stroke and myocardial infarction are definable but not the plaque burden.Platelet indices including platelet count and mean platelet volume and soluble mediators released by activated platelets are associated with atherosclerosis. The chemokine CXCL4 has multiple atherogenic activities e.g. altering the differentiation of T cells and macrophages by inhibiting neutrophil and monocyte apoptosis and by increasing the uptake of oxLDL and synergizing with CCL5. CCL5 is released and deposited on endothelium by activated platelets thereby triggering atherogenic monocyte recruitment, which can be attenuated by blocking the corresponding chemokine receptor CCR5. Atheroprotective and plaque stabilizing properties are attributed to CXCL12, which plays an important role in regenerative processes by attracting progenitor cells. Its release from luminal attached platelets accelerates endothelial healing after injury. Platelet surface molecules GPIIb/IIIa, GP1bα, P-selectin, JAM-A and the CD40/CD40L dyade are crucially involved in the interaction with endothelial cells, leukocytes and matrix molecules affecting atherogenesis. Beyond the effects on the arterial inflammatory infiltrate, platelets affect cholesterol metabolism by binding, modifying and endocytosing LDL particles via their scavenger receptors and contribute to the formation of lipid laden macrophages. Current medical therapies for the prevention of atherosclerotic therapies enable the elucidation of mechanisms linking platelets to inflammation

Protein mobilities and P-selectin storage in Weibel–Palade bodies

OpenAIRE

Kiskin, Nikolai I.; Hellen, Nicola; Babich, Victor; Hewlett, Lindsay; Knipe, Laura; Hannah, Matthew J.; Carter, Tom

2010-01-01

Using fluorescence recovery after photobleaching (FRAP) we measured the mobilities of EGFP-tagged soluble secretory proteins in the endoplasmic reticulum (ER) and in individual Weibel–Palade bodies (WPBs) at early (immature) and late (mature) stages in their biogenesis. Membrane proteins (P-selectin, CD63, Rab27a) were also studied in individual WPBs. In the ER, soluble secretory proteins were mobile; however, following insertion into immature WPBs larger molecules (VWF, Proregion, tPA) and P...

Thrombopoietin contributes to enhanced platelet activation in cigarette smokers.

Science.gov (United States)

Lupia, Enrico; Bosco, Ornella; Goffi, Alberto; Poletto, Cesare; Locatelli, Stefania; Spatola, Tiziana; Cuccurullo, Alessandra; Montrucchio, Giuseppe

2010-05-01

Thrombopoietin (TPO) is a humoral growth factor that primes platelet activation in response to several agonists. We recently showed that TPO enhances platelet activation in unstable angina and sepsis. Aim of this study was to investigate the role of TPO in platelet function abnormalities described in cigarette smokers. In a case-control study we enrolled 20 healthy cigarette smokers and 20 nonsmokers, and measured TPO and C-reactive protein (CRP), as well as platelet-leukocyte binding and P-selectin expression. In vitro we evaluated the priming activity of smoker or control plasma on platelet activation, and the role of TPO in this effect. We then studied the effects of acute smoking and smoking cessation on TPO levels and platelet activation indices. Chronic cigarette smokers had higher circulating TPO levels than nonsmoking controls, as well as increased platelet-leukocyte binding, P-selectin expression, and CRP levels. Serum cotinine concentrations correlated with TPO concentrations, platelet-monocyte aggregates and P-selectin expression. In addition, TPO levels significantly correlated with ex vivo platelet-monocyte aggregation and P-selectin expression. In vitro, the plasma from cigarette smokers, but not from nonsmoking controls, primed platelet-monocyte binding, which was reduced when an inhibitor of TPO was used. We also found that acute smoking slightly increased TPO levels, but did not affect platelet-leukocyte binding, whereas smoking cessation induced a significant decrease in both circulating TPO and platelet-leukocyte aggregation. Elevated TPO contributes to enhance platelet activation and platelet-monocyte cross-talk in cigarette smokers. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Platelet activation and inflammation markers as emerging risk ...

African Journals Online (AJOL)

Platelet activation and inflammation markers were assessed by measuring plasma levels of sP-selectin, platelet factor 4 (PF4), IL-6 and tumor necrosis factor alpha (TNF-α). Results: HIV infected patients had higher levels of sP- selectin, PF4 and IL-6 than uninfected controls (p<0.001). ART naïve subjects had higher levels ...

Differing patterns of P-selectin expression in lung injury

DEFF Research Database (Denmark)

Bless, N M; Tojo, S J; Kawarai, H

1998-01-01

Using two models of acute lung inflammatory injury in rats (intrapulmonary deposition of immunoglobulin G immune complexes and systemic activation of complement after infusion of purified cobra venom factor), we have analyzed the requirements and patterns for upregulation of lung vascular P......-selectin. In the immune complex model, upregulation of P-selectin was defined by Northern and Western blot analysis of lung homogenates, by immunostaining of lung tissue, and by vascular fixation of 125I-labeled anti-P-selectin. P-selectin protein was detected by 1 hour (long before detection of mRNA) and expression......-selectin was dependent on an intact complement system, and the presence of blood neutrophils was susceptible to the antioxidant dimethyl sulfoxide and required C5a but not tumor necrosis factor alpha. In contrast, in the cobra venom factor model, upregulation of P-selectin, which is C5a dependent, was also dimethyl...

Stem Cell Enrichment with Selectin Receptors: Mimicking the pH Environment of Trauma

Directory of Open Access Journals (Sweden)

Michael R. King

2013-09-01

Full Text Available The isolation of hematopoietic stem and progenitor cells (HSPCs is critical for transplantation therapy and HSPC research, however current isolation techniques can be prohibitively expensive, time-consuming, and produce variable results. Selectin-coated microtubes have shown promise in rapidly isolating HSPCs from human bone marrow, but further purification of HSPCs remains a challenge. Herein, a biomimetic device for HSPC isolation is presented to mimic the acidic vascular microenvironment during trauma, which can enhance the binding frequency between L-selectin and its counter-receptor PSGL-1 and HSPCs. Under acidic pH conditions, L-selectin coated microtubes enhanced CD34+ HSPC adhesion, as evidenced by decreased cell rolling velocity and increased rolling flux. Dynamic light scattering was utilized as a novel sensor to confirm an L-selectin conformational change under acidic conditions, as previously predicted by molecular dynamics. These results suggest that mimicking the acidic conditions of trauma can induce a conformational extension of L-selectin, which can be utilized for flow-based, clinical isolation of HSPCs.

Sphingosine 1-phosphate (S1P) suppresses the collagen-induced activation of human platelets via S1P4 receptor.

Science.gov (United States)

Onuma, Takashi; Tanabe, Kumiko; Kito, Yuko; Tsujimoto, Masanori; Uematsu, Kodai; Enomoto, Yukiko; Matsushima-Nishiwaki, Rie; Doi, Tomoaki; Nagase, Kiyoshi; Akamatsu, Shigeru; Tokuda, Haruhiko; Ogura, Shinji; Iwama, Toru; Kozawa, Osamu; Iida, Hiroki

2017-08-01

Sphingosine 1-phosphate (S1P) is as an extracellular factor that acts as a potent lipid mediator by binding to specific receptors, S1P receptors (S1PRs). However, the precise role of S1P in human platelets that express S1PRs has not yet been fully clarified. We previously reported that heat shock protein 27 (HSP27) is released from human platelets accompanied by its phosphorylation stimulated by collagen. In the present study, we investigated the effect of S1P on the collagen-induced platelet activation. S1P pretreatment markedly attenuated the collagen-induced aggregation. Co-stimulation with S1P and collagen suppressed collagen-induced platelet activation, but the effect was weaker than that of S1P-pretreatment. The collagen-stimulated secretion of platelet-derived growth factor (PDGF)-AB and the soluble CD40 ligand (sCD40L) release were significantly reduced by S1P. In addition, S1P suppressed the collagen-induced release of HSP27 as well as the phosphorylation of HSP27. S1P significantly suppressed the collagen-induced phosphorylation of p38 mitogen-activated protein kinase. S1P increased the levels of GTP-bound Gαi and GTP-bound Gα13 coupled to S1PPR1 and/or S1PR4. CYM50260, a selective S1PR4 agonist, but not SEW2871, a selective S1PR1 agonist, suppressed the collagen-stimulated platelet aggregation, PDGF-AB secretion and sCD40L release. In addition, CYM50260 reduced the release of phosphorylated-HSP27 by collagen as well as the phosphorylation of HSP27. The selective S1PR4 antagonist CYM50358, which failed to affect collagen-induced HSP27 phosphorylation, reversed the S1P-induced attenuation of HSP27 phosphorylation by collagen. These results strongly suggest that S1P inhibits the collagen-induced human platelet activation through S1PR4 but not S1PR1. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of canine autologous platelet-rich plasma produced with a commercial centrifugation and platelet recovery kit.

Science.gov (United States)

Frye, Chris W; Enders, Andrew; Brooks, Marjory B; Struble, Angela M; Wakshlag, Joseph J

2016-01-01

To characterize the cellular composition (platelets, erythrocytes, and leukocytes) and confirm reproducibility of platelet enrichment, as well as determine the platelet activation status in the final product of a commercial platelet-rich plasma kit using canine blood. Venous blood from 20 sedated client-owned dogs was used to prepare platelet-rich plasma (PRP) from a commercial kit. Complete blood counts were performed to determine erythrocyte, leukocyte, and platelet numbers in both whole blood (WB) and resultant PRP. The WB and PRP samples from jugular (fast collection) and cephalic (slow collection) venipuncture were also compared. P-selectin externalization was measured in WB and PRP samples from 15 of 20 dogs. This commercial kit produced an average percent recovery in platelets of 64.7 ± 17.4; erythrocytes of 3.7 ± 0.8, and leukocytes of 31.6 ± 10.0. Neutrophil, monocyte, and lymphocyte percent recovery was 19.6 ± 7.2, 44.89 ± 19.8, and 57.5 ± 10.6, respectively. The recovery of platelets from jugular venipuncture (59.7 ± 13.6%) was lower than from cephalic recovery (68.8 ± 19.1%). The mean percent P-Selectin externalization for WB, PRP, and PRP with thrombin was 25.5 ± 30.9, 4.5 ± 6.4, and 90.6 ± 4.4 respectively. Cellular reproducibility of this kit was confirmed and platelets were concentrated within autologous serum. Additionally, measurements of P-selectin externalization showed that platelets are inactive in PRP unless stimulated to degranulate.

Lack of evidence of CD40 ligand involvement in transfusion-related acute lung injury

NARCIS (Netherlands)

Tuinman, P. R.; Gerards, M. C.; Jongsma, G.; Vlaar, A. P.; Boon, L.; Juffermans, N. P.

2011-01-01

Activated platelets have been implicated in playing a major role in transfusion-related acute lung injury (TRALI), as platelets can trigger neutrophils, resulting in vascular damage. We hypothesized that binding of platelet CD40 ligand (CD40L) to endothelial CD40 is essential in the onset of TRALI.

Platelet proteome reveals novel pathways of platelet activation and platelet-mediated immunoregulation in dengue.

Directory of Open Access Journals (Sweden)

Monique Ramos de Oliveira Trugilho

2017-05-01

Full Text Available Dengue is the most prevalent human arbovirus disease worldwide. Dengue virus (DENV infection causes syndromes varying from self-limiting febrile illness to severe dengue. Although dengue pathophysiology is not completely understood, it is widely accepted that increased inflammation plays important roles in dengue pathogenesis. Platelets are blood cells classically known as effectors of hemostasis which have been increasingly recognized to have major immune and inflammatory activities. Nevertheless, the phenotype and effector functions of platelets in dengue pathogenesis are not completely understood. Here we used quantitative proteomics to investigate the protein content of platelets in clinical samples from patients with dengue compared to platelets from healthy donors. Our assays revealed a set of 252 differentially abundant proteins. In silico analyses associated these proteins with key molecular events including platelet activation and inflammatory responses, and with events not previously attributed to platelets during dengue infection including antigen processing and presentation, proteasome activity, and expression of histones. From these results, we conducted functional assays using samples from a larger cohort of patients and demonstrated evidence for platelet activation indicated by P-selectin (CD62P translocation and secretion of granule-stored chemokines by platelets. In addition, we found evidence that DENV infection triggers HLA class I synthesis and surface expression by a mechanism depending on functional proteasome activity. Furthermore, we demonstrate that cell-free histone H2A released during dengue infection binds to platelets, increasing platelet activation. These findings are consistent with functional importance of HLA class I, proteasome subunits, and histones that we found exclusively in proteome analysis of platelets in samples from dengue patients. Our study provides the first in-depth characterization of the platelet

Crosstalk between Platelets and the Immune System: Old Systems with New Discoveries

Directory of Open Access Journals (Sweden)

Conglei Li

2012-01-01

Full Text Available Platelets are small anucleate cells circulating in the blood. It has been recognized for more than 100 years that platelet adhesion and aggregation at the site of vascular injury are critical events in hemostasis and thrombosis; however, recent studies demonstrated that, in addition to these classic roles, platelets also have important functions in inflammation and the immune response. Platelets contain many proinflammatory molecules and cytokines (e.g., P-selectin, CD40L, IL-1β, etc., which support leukocyte trafficking, modulate immunoglobulin class switch, and germinal center formation. Platelets express several functional Toll-like receptors (TLRs, such as TLR-2, TLR-4, and TLR-9, which may potentially link innate immunity with thrombosis. Interestingly, platelets also contain multiple anti-inflammatory molecules and cytokines (e.g., transforming growth factor-β and thrombospondin-1. Emerging evidence also suggests that platelets are involved in lymphatic vessel development by directly interacting with lymphatic endothelial cells through C-type lectin-like receptor 2. Besides the active contributions of platelets to the immune system, platelets are passively targeted in several immune-mediated diseases, such as autoimmune thrombocytopenia, infection-associated thrombocytopenia, and fetal and neonatal alloimmune thrombocytopenia. These data suggest that platelets are important immune cells and may contribute to innate and adaptive immunity under both physiological and pathological conditions.

Molecular Characterization of the Interactions between Vascular Selectins and Glycoprotein Ligands on Human Hematopoietic Stem/Progenitor Cells

KAUST Repository

Abusamra, Dina

2016-12-01

The human bone marrow vasculature constitutively expresses both E-selectin and P-selectin where they interact with the cell-surface glycan moiety, sialyl Lewis x, on circulating hematopoietic stem/progenitor cells (HSPCs) to mediate the essential tethering/rolling step. Although several E-selectin glycoprotein ligands (E-selLs) have been identified, the importance of each E-selL on human HSPCs is debatable and requires additional methodologies to advance their specific involvement. The first objective was to fill the knowledge gap in the in vitro characterization of the mechanisms used by selectins to mediate the initial step in the HSPCs homing by developing a real time immunoprecipitation-based assay on a surface plasmon resonance chip. This novel assay bypass the difficulties of purifying ligands, enables the use of natively glycosylated forms of selectin ligands from any model cell of interest and study its binding affinities under flow. We provide the first comprehensive quantitative binding kinetics of two well-documented ligands, CD44 and PSGL-1, with E-selectin. Both ligands bind monomeric E-selectin transiently with fast on- and off-rates while they bind dimeric E-selectin with remarkably slow on- and off-rates with the on-rate, but not the off-rate, is dependent on salt concentration. Thus, suggest a mechanism through which monomeric selectins mediate initial fast-on and -off binding to capture the circulating cells out of shear-flow; subsequently, tight binding by dimeric/oligomeric selectins is enabled to slow rolling significantly. The second objective is to fully identify and characterize E/P-selectin ligand candidates expressed on CD34+ HSPCs which cause enhanced migration after intravenous transplantation compared to their CD34- counterparts. CD34 is widely recognized marker of human HSPCs but its natural ligand and function on these cells remain elusive. Proteomics identified CD34 as an E-selL candidate on human HSPCs, whose binding to E-selectin

Secreted Immunomodulatory Proteins of Staphylococcus aureus Activate Platelets and Induce Platelet Aggregation.

Science.gov (United States)

Binsker, Ulrike; Palankar, Raghavendra; Wesche, Jan; Kohler, Thomas P; Prucha, Josephine; Burchhardt, Gerhard; Rohde, Manfred; Schmidt, Frank; Bröker, Barbara M; Mamat, Uwe; Pané-Farré, Jan; Graf, Anica; Ebner, Patrick; Greinacher, Andreas; Hammerschmidt, Sven

2018-04-01

Staphylococcus aureus can cause bloodstream infections associated with infective endocarditis (IE) and disseminated intravascular coagulopathy (DIC). Both complications involve platelets. In view of an increasing number of antibiotic-resistant strains, new approaches to control systemic S. aureus infection are gaining importance. Using a repertoire of 52 recombinant S. aureus proteins in flow cytometry-based platelet activation and aggregation assays, we identified, in addition to the extracellular adherence protein Eap, three secreted staphylococcal proteins as novel platelet activating proteins. Eap and the chemotaxis inhibitory protein of S. aureus (CHIPS), the formyl peptide receptor-like 1 inhibitory protein (FLIPr) and the major autolysin Atl induced P-selectin expression in washed platelets and platelet-rich plasma. Similarly, AtlA, CHIPS and Eap induced platelet aggregation in whole blood. Fluorescence microscopy illustrated that P-selectin expression is associated with calcium mobilization and re-organization of the platelet actin cytoskeleton. Characterization of the functionally active domains of the major autolysin AtlA and Eap indicates that the amidase domain of Atl and the tandem repeats 3 and 4 of Eap are crucial for platelet activation. These results provide new insights in S. aureus protein interactions with platelets and identify secreted proteins as potential treatment targets in case of antibiotic-resistant S. aureus infection. Schattauer GmbH Stuttgart.

Cancer cell–derived microparticles bearing P-selectin glycoprotein ligand 1 accelerate thrombus formation in vivo

Science.gov (United States)

Thomas, Grace M.; Panicot-Dubois, Laurence; Lacroix, Romaric; Dignat-George, Françoise; Lombardo, Dominique

2009-01-01

Recent publications have demonstrated the presence of tissue factor (TF)–bearing microparticles (MPs) in the blood of patients suffering from cancer. However, whether these MPs are involved in thrombosis remains unknown. We show that pancreatic and lung cancer cells produce MPs that express active TF and P-selectin glycoprotein ligand 1 (PSGL-1). Cancer cell–derived MPs aggregate platelets via a TF-dependent pathway. In vivo, cancer cell–derived MPs, but not their parent cells, infused into a living mouse accumulate at the site of injury and reduce tail bleeding time and the time to occlusion of venules and arterioles. This thrombotic state is also observed in mice developing tumors. In such mice, the amount of circulating platelet-, endothelial cell–, and cancer cell–derived MPs is increased. Endogenous cancer cell–derived MPs shed from the growing tumor are able to accumulate at the site of injury. Infusion of a blocking P-selectin antibody abolishes the thrombotic state observed after injection of MPs or in mice developing a tumor. Collectively, our results indicate that cancer cell–derived MPs bearing PSGL-1 and TF play a key role in thrombus formation in vivo. Targeting these MPs could be of clinical interest in the prevention of thrombosis and to limit formation of metastasis in cancer patients. PMID:19667060

Molecular Characterization of the Interactions between Vascular Selectins and Glycoprotein Ligands on Human Hematopoietic Stem/Progenitor Cells

KAUST Repository

Abu Samra, Dina Bashir Kamil

2016-01-01

The first objective was to fill the knowledge gap in the in vitro characterization of the mechanisms used by selectins to mediate the initial step in the HSPCs homing by developing a real time immunoprecipitation-based assay on a surface plasmon resonance chip. This novel assay bypass the difficulties of purifying ligands, enables the use of natively glycosylated forms of selectin ligands from any model cell of interest and study its binding affinities under flow. We provide the first comprehensive quantitative binding kinetics of two well-documented ligands, CD44 and PSGL-1, with E-selectin. Both ligands bind monomeric E-selectin transiently with fast on- and off-rates while they bind dimeric E-selectin with remarkably slow on- and off-rates with the on-rate, but not the off-rate, is dependent on salt concentration. Thus, suggest a mechanism through which monomeric selectins mediate initial fast-on and -off binding to capture the circulating cells out of shear-flow; subsequently, tight binding by dimeric/oligomeric selectins is enabled to slow rolling significantly. The second objective is to fully identify and characterize E/P-selectin ligand candidates expressed on CD34+ HSPCs which cause enhanced migration after intravenous transplantation compared to their CD34- counterparts. CD34 is widely recognized marker of human HSPCs but its natural ligand and function on these cells remain elusive. Proteomics identified CD34 as an E-selL candidate on human HSPCs, whose binding to E-selectin was confirmed using some static and flow-based assays. E-selectin binds to CD34 with an affinity comparable to the well-described E-selLs CD44/HCELL and PSGL-1. CD34 knockdown resulted in faster-rolling velocities compared to control cells especially at and above three dyne/cm2. CD34 is the first selectin ligand since PSGL-1 reported to bind E-/P-/L-selectins and likely plays a key role in directing the migration of human HSPCs to the bone marrow.

Plasma substance P and soluble P-selectin as biomarkers of β ...

African Journals Online (AJOL)

Samia A. Ebeid

2013-09-19

Sep 19, 2013 ... logic disorder that causes hemolytic anemia because of the de- creased or absent .... AMs), sE-selectin, sP-selectin in sickle cell patients compared to healthy individuals. .... with childhood sickle cell · vasoocclusive crises.

Responsiveness of platelets during storage studied with flow cytometry--formation of platelet subpopulations and LAMP-1 as new markers for the platelet storage lesion.

Science.gov (United States)

Södergren, A L; Tynngård, N; Berlin, G; Ramström, S

2016-02-01

Storage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation. Activation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lysosome-associated membrane protein-1 (LAMP-1), P-selectin and phosphatidylserine (PS) exposure were assessed by flow cytometry on platelets in different subpopulations in resting state or following stimulation with platelet agonists (cross-linked collagen-related peptide (CRP-XL), PAR1- and PAR4-activating peptides). The ability to form subpopulations upon activation was significantly decreased already at day 5 for some agonist combinations. The agonist-induced exposure of PS and LAMP-1 also gradually decreased with time. Spontaneous exposure of P-selectin and PS increased with time, while spontaneous LAMP-1 exposure was unchanged. In addition, agonist-induced LAMP-1 expression clearly discriminated platelet concentrates with reduced swirling from those with retained swirling. This suggests that LAMP-1 could be a good marker to capture changes in activation capacity in stored platelets. The platelet activation potential seen as LAMP-1 exposure and fragmentation into platelet subpopulations is potential sensitive markers for the platelet storage lesion. © 2015 International Society of Blood Transfusion.

New in vitro effects of clopidogrel on platelets in hyperlipidemic and healthy subjects

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Derya Özsavcı

2010-06-01

Full Text Available Objective: We aimed to detect novel in vitro effects of clopidogrel on platelets by assessment of the following parameters: malondialdehyde, glutathione, nitrite, aggregation response, and expressions of P-selectin, fibrinogen, apolipoprotein A1, apolipoprotein B, and phosphatidylserine.Materials and Methods: Platelets were obtained from healthy (n: 9 and hyperlipidemic (n: 9 volunteers. Expressions of P-selectin, fibrinogen, apolipoproteins A1/B and phosphatidylserine with and without clopidogrel were assayed by flow cytometry. Malondialdehyde, glutathione, aggregation and nitrite levels were also assayed. Results: Without clopidogrel, the baseline values of platelet aggregation, malondialdehyde, and expressions of P-selectin, fibrinogen and phosphatidylserine were significantly higher, whereas nitrite and expression of apolipoproteins A1/B were significantly lower in hyperlipidemics than in the healthy group. In both groups, clopidogrel significantly reduced aggregation and expression of fibrinogen, but it elevated nitrite levels. Clopidogrel significantly decreased P-selectin and phosphatidylserine expression and malondialdehyde but increased expressions of apolipoproteins A1/B only in hyperlipidemics. Conclusion: It seems that clopidogrel has some new in vitro antiplatelet effects. The present study is a basic in vitro study to suggest new insights into the effects of clopidogrel on platelet functions.

Soluble CD40 Ligand and Oxidative Response Are Reciprocally Stimulated during Shiga Toxin-Associated Hemolytic Uremic Syndrome

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Maria J. Abrey Recalde

2017-10-01

Full Text Available Shiga toxin (Stx, produced by Escherichia coli, is the main pathogenic factor of diarrhea-associated hemolytic uremic syndrome (HUS, which is characterized by the obstruction of renal microvasculature by platelet-fibrin thrombi. It is well known that the oxidative imbalance generated by Stx induces platelet activation, contributing to thrombus formation. Moreover, activated platelets release soluble CD40 ligand (sCD40L, which in turn contributes to oxidative imbalance, triggering the release of reactive oxidative species (ROS on various cellular types. The aim of this work was to determine if the interaction between the oxidative response and platelet-derived sCD40L, as consequence of Stx-induced endothelium damage, participates in the pathogenic mechanism during HUS. Activated human glomerular endothelial cells (HGEC by Stx2 induced platelets to adhere to them. Although platelet adhesion did not contribute to endothelial damage, high levels of sCD40L were released to the medium. The release of sCD40L by activated platelets was inhibited by antioxidant treatment. Furthermore, we found increased levels of sCD40L in plasma from HUS patients, which were also able to trigger the respiratory burst in monocytes in a sCD40L-dependent manner. Thus, we concluded that platelet-derived sCD40L and the oxidative response are reciprocally stimulated during Stx2-associated HUS. This process may contribute to the evolution of glomerular occlusion and the microangiopathic lesions.

Soluble CD40 Ligand and Oxidative Response Are Reciprocally Stimulated during Shiga Toxin-Associated Hemolytic Uremic Syndrome

Science.gov (United States)

Abrey Recalde, Maria J.; Alvarez, Romina S.; Alberto, Fabiana; Mejias, Maria P.; Ramos, Maria V.; Fernandez Brando, Romina J.; Bruballa, Andrea C.; Exeni, Ramon A.; Alconcher, Laura; Ibarra, Cristina A.; Amaral, María M.; Palermo, Marina S.

2017-01-01

Shiga toxin (Stx), produced by Escherichia coli, is the main pathogenic factor of diarrhea-associated hemolytic uremic syndrome (HUS), which is characterized by the obstruction of renal microvasculature by platelet-fibrin thrombi. It is well known that the oxidative imbalance generated by Stx induces platelet activation, contributing to thrombus formation. Moreover, activated platelets release soluble CD40 ligand (sCD40L), which in turn contributes to oxidative imbalance, triggering the release of reactive oxidative species (ROS) on various cellular types. The aim of this work was to determine if the interaction between the oxidative response and platelet-derived sCD40L, as consequence of Stx-induced endothelium damage, participates in the pathogenic mechanism during HUS. Activated human glomerular endothelial cells (HGEC) by Stx2 induced platelets to adhere to them. Although platelet adhesion did not contribute to endothelial damage, high levels of sCD40L were released to the medium. The release of sCD40L by activated platelets was inhibited by antioxidant treatment. Furthermore, we found increased levels of sCD40L in plasma from HUS patients, which were also able to trigger the respiratory burst in monocytes in a sCD40L-dependent manner. Thus, we concluded that platelet-derived sCD40L and the oxidative response are reciprocally stimulated during Stx2-associated HUS. This process may contribute to the evolution of glomerular occlusion and the microangiopathic lesions. PMID:29068360

Quantitative Glycoproteomic Analysis Identifies Platelet-Induced Increase of Monocyte Adhesion via the Up-Regulation of Very Late Antigen 5.

Science.gov (United States)

Huang, Jiqing; Kast, Juergen

2015-08-07

Physiological stimuli, such as thrombin, or pathological stimuli, such as lysophosphatidic acid (LPA), activate platelets circulating in blood. Once activated, platelets bind to monocytes via P-selectin-PSGL-1 interactions but also release the stored contents of their granules. These platelet releasates, in addition to direct platelet binding, activate monocytes and facilitate their recruitment to atherosclerotic sites. Consequently, understanding the changes platelet releasates induce in monocyte membrane proteins is critical. We studied the glyco-proteome changes of THP-1 monocytic cells affected by LPA- or thrombin-induced platelet releasates. We employed lectin affinity chromatography combined with filter aided sample preparation to achieve high glyco- and membrane protein and protein sequence coverage. Using stable isotope labeling by amino acids in cell culture, we quantified 1715 proteins, including 852 membrane and 500 glycoproteins, identifying the up-regulation of multiple proteins involved in monocyte extracellular matrix binding and transendothelial migration. Flow cytometry indicated expression changes of integrin α5, integrin β1, PECAM-1, and PSGL-1. The observed increase in monocyte adhesion to fibronectin was determined to be mediated by the up-regulation of very late antigen 5 via a P-selectin-PSGL-1 independent mechanism. This novel aspect could be validated on CD14+ human primary monocytes, highlighting the benefits of the improved enrichment method regarding high membrane protein coverage and reliable quantification.

Evolutionary conservation of P-selectin glycoprotein ligand-1 primary structure and function

Directory of Open Access Journals (Sweden)

Schapira Marc

2007-09-01

Full Text Available Abstract Background P-selectin glycoprotein ligand-1 (PSGL-1 plays a critical role in recruiting leukocytes in inflammatory lesions by mediating leukocyte rolling on selectins. Core-2 O-glycosylation of a N-terminal threonine and sulfation of at least one tyrosine residue of PSGL-1 are required for L- and P-selectin binding. Little information is available on the intra- and inter-species evolution of PSGL-1 primary structure. In addition, the evolutionary conservation of selectin binding site on PSGL-1 has not been previously examined in detail. Therefore, we performed multiple sequence alignment of PSGL-1 amino acid sequences of 14 mammals (human, chimpanzee, rhesus monkey, bovine, pig, rat, tree-shrew, bushbaby, mouse, bat, horse, cat, sheep and dog and examined mammalian PSGL-1 interactions with human selectins. Results A signal peptide was predicted in each sequence and a propeptide cleavage site was found in 9/14 species. PSGL-1 N-terminus is poorly conserved. However, each species exhibits at least one tyrosine sulfation site and, except in horse and dog, a T [D/E]PP [D/E] motif associated to the core-2 O-glycosylation of a N-terminal threonine. A mucin-like domain of 250–280 amino acids long was disclosed in all studied species. It lies between the conserved N-terminal O-glycosylated threonine (Thr-57 in human and the transmembrane domain, and contains a central region exhibiting a variable number of decameric repeats (DR. Interspecies and intraspecies polymorphisms were observed. Transmembrane and cytoplasmic domain sequences are well conserved. The moesin binding residues that serve as adaptor between PSGL-1 and Syk, and are involved in regulating PSGL-1-dependent rolling on P-selectin are perfectly conserved in all analyzed mammalian sequences. Despite a poor conservation of PSGL-1 N-terminal sequence, CHO cells co-expressing human glycosyltransferases and human, bovine, pig or rat PSGL-1 efficiently rolled on human L- or P-selectin

Role of Tumor Suppressor P53 in Megakaryopoiesis and Platelet Function

Science.gov (United States)

Apostolidis, Pani A.; Woulfe, Donna S.; Chavez, Massiel; Miller, William M.; Papoutsakis, Eleftherios T.

2011-01-01

The pathobiological role of p53 has been widely studied, however its role in normophysiology is relatively unexplored. We previously showed that p53 knock-down increased ploidy in megakaryocytic cultures. This study aims to examine the effect of p53 loss on in vivo megakaryopoiesis, platelet production and function, and to investigate the basis for greater ploidy in p53−/− megakaryocytic cultures. Here, we used flow cytometry to analyze ploidy, DNA synthesis and apoptosis in murine cultured and bone marrow megakaryocytes following thrombopoietin administration and to analyze fibrinogen binding to platelets in vitro. Culture of p53−/− marrow cells for 6 days with thrombopoietin gave rise to 1.7-fold more megakaryocytes, 26.1±3.6% of which reached ploidy classes ≥64N compared to 8.2±0.9% of p53+/+ megakaryocytes. This was due to 30% greater DNA synthesis in p53−/− megakaryocytes and 31% greater apoptosis in p53+/+ megakaryocytes by day 4 of culture. Although the bone marrow and spleen steady-state megakaryocytic content and ploidy were similar in p53+/+ and p53−/− mice, thrombopoietin administration resulted in increased megakaryocytic polyploidization in p53−/− mice. Although their platelet counts were normal, p53−/− mice exhibited significantly longer bleeding times and p53−/− platelets were less sensitive than p53+/+ platelets to agonist-induced fibrinogen binding and P-selectin secretion. In summary, our in vivo and ex-vivo studies indicate that p53 loss leads to increased polyploidization during megakaryopoiesis. Our findings also suggest for the first time a direct link between p53 loss and the development of fully functional platelets resulting in hemostatic deficiencies. PMID:22024107

P-Selectin: An Unpredicted Factor for Deep Vein Thrombosis after Total Hip Arthroplasty

Directory of Open Access Journals (Sweden)

Dongquan Shi

2014-01-01

Full Text Available Introduction. Deep vein thrombosis (DVT is a severe complication after total hip arthroplasty (THA. It leads to acute pulmonary embolism, a life-threatening disease. P-selectin is a 140-kDa transmembrane glycoprotein. Elevated P-selectin was associated with 1.7-fold increase in the risk of venous thrombosis. Materials and Methods. To confirm the association, a total of 91 subjects who received primary total hip arthroplasty using lateral approach performed by one skilled orthopedic surgeon were studied. All the patients were consecutively enrolled at the Center of Diagnosis and Treatment for Joint Diseases, Drum Tower Hospital affiliated to the Medical School of Nanjing University from 2010 to 2012. All the subjects received venography 3–5 days after operation. We measured P-selectin by means of a highly sensitive sandwich ELISA technique and a commercially available test reagent set. Results. No significant association was detected between P-selectin and DVT (all P  values>0.05. ΔsP-selectin was correlated with weight, APTT after operation, history of DVT, and diagnosis of primary disease ( P values were 0.03, 0.03, 0.04, and 0.02, resp.. Conclusion. P-selectin may not be a predicted factor for deep vein thrombosis after total hip arthroplasty.

Elevated thrombopoietin in plasma of burned patients without and with sepsis enhances platelet activation.

Science.gov (United States)

Lupia, E; Bosco, O; Mariano, F; Dondi, A E; Goffi, A; Spatola, T; Cuccurullo, A; Tizzani, P; Brondino, G; Stella, M; Montrucchio, G

2009-06-01

Thrombopoietin (TPO) is a humoral growth factor that does not induce platelet aggregation per se, but enhances platelet activation in response to several agonists. Circulating levels of TPO are increased in patients with sepsis and are mainly related to sepsis severity. To investigate the potential contribution of elevated TPO levels in platelet activation during burn injury complicated or not by sepsis. We studied 22 burned patients, 10 without and 12 with sepsis, and 10 healthy subjects. We measured plasma levels of TPO, as well as leukocyte-platelet binding and P-selectin expression. The priming activity of plasma from burned patients or healthy subjects on platelet aggregation and leukocyte-platelet binding, and the role of TPO in these effects were also studied in vitro. Burned patients without and with sepsis showed higher circulating TPO levels and increased monocyte-platelet binding compared with healthy subjects. Moreover, TPO levels, monocyte-platelet binding and P-selectin expression were significantly higher in burned patients with sepsis than in burned patients without sepsis. In vitro, plasma from burned patients without and with sepsis, but not from healthy subjects, primed platelet aggregation, monocyte-platelet binding and platelet P-selectin expression. The effect of plasma from burned patients with sepsis was significantly higher than that of plasma from burned patients without sepsis. An inhibitor of TPO prevented the priming effect of plasma from burned patients. Increased TPO levels may enhance platelet activation during burn injury and sepsis, potentially participating in the pathogenesis of multi-organ failure in these diseases.

Analysis of glycoprotein E-selectin ligANDs on human and mouse marrow cells enriched for hematopoietic stem/progenitor cells

KAUST Repository

Merzaban, Jasmeen S.

2011-06-09

Although well recognized that expression of E-selectin on marrow microvessels mediates osteotropism of hematopoietic stem/progenitor cells (HSPCs), our knowledge regarding the cognate E-selectin ligand(s) on HSPCs is incomplete. Flow cytometry using E-selectin-Ig chimera (E-Ig) shows that human marrow cells enriched for HSPCs (CD34+ cells) display greater E-selectin binding than those obtained from mouse (lin-/Sca-1+/c-kit+ [LSK] cells). To define the relevant glycoprotein E-selectin ligands, lysates from human CD34+ and KG1a cells and from mouse LSK cells were immunoprecipitated using E-Ig and resolved byWestern blot using E-Ig. In both human and mouse cells, E-selectin ligand reactivity was observed at ∼ 120- to 130-kDa region, which contained two E-selectin ligands, the P-selectin glycoprotein ligand- 1 glycoform "CLA," and CD43. Human, but not mouse, cells displayed a prominent ∼ 100-kDa band, exclusively comprising the CD44 glycoform "HCELL."E-Ig reactivity was most prominent on CLA in mouse cells and on HCELL in human cells. To further assess HCELL\\'s contribution to E-selectin adherence, complementary studies were performed to silence (via CD44 siRNA) or enforce its expression (via exoglycosylation). Under physiologic shear conditions, CD44/HCELL-silenced human cells showed striking decreases (> 50%) in E-selectin binding. Conversely, enforced HCELL expression of LSK cells profoundly increased E-selectin adherence, yielding > 3-fold more marrow homing in vivo. These data define the key glycoprotein E-selectin ligands of human and mouse HSPCs, unveiling critical species-intrinsic differences in both the identity and activity of these structures. © 2011 by The American Society of Hematology.

Six hours of resting platelet concentrates stored at 22-24 ºC for 48 hours in permeable bags preserved pH, swirling and lactate dehydrogenase better and caused less platelet activation.

Science.gov (United States)

Naghadeh, Hossin T; Badlou, Bahram A; Ferizhandy, Ali S; Mohammadreza, Tabatabai S; Shahram, Vaeli

2013-07-01

During transportation, platelet concentrates (PC) usually undergo a long period without agitation. Whether this interruption improves quality and viability or, contrariwise, has deleterious effects on PC stored for 48 hours (h) is unknown. The aim of this study was to investigate the effects of metabolic resting (6 h of interruption of agitation) vs continue agitation of PC stored for 48 h in the blood bank of Tehran. PC were prepared from platelet-rich plasma and stored in permeable bags in a shaker/incubator for 42 h at room temperature (20-24 ºC). Then, simply by stopping the agitator, the PC remained stationary ("resting") without agitation for 6 h (WCA6h), prior to transfusion. In vitro measurements of platelet quality were carried out just after completion of the resting period and the results were compared with those of PC continuously agitated in the same day (designated as the control group, CA6h). The in vitro variables measured were swirling, ristocetin-induced aggregation (GPIb-related function), lactate dehydrogenase (LDH) concentration, platelet factor 4 (PF4) release and P-selectin expression (activation markers). The mean platelet counts of the control group (CA6h) and rested (WCA6h) PC were not statistically different (P =0.548). Likewise, the mean pH values were not significantly different: WCA6h (7.16 ± 0.08) and CA6h (7.22 ± 0.16) (P =0.300). Although ristocetin-induced aggregation did not differ significantly between CA6h (79.2 ± 4.4) and WCA6h (66.65 ± 28.55) (P =0.186), WCA6h showed significantly less PFA release (P =0.015) and lower P-selectin expression (P =0.006). We observed that PC stored under agitation for 42 h at 22-24 ºC in permeable bags and then rested for 6 h had better preserved pH, swirling and LDH and less platelet activation then PC kept under continuous agitation for the whole 48 h storage period.

CD40-mediated apoptosis in murine B-lymphoma lines containing mutated p53

DEFF Research Database (Denmark)

Hollmann, Annette C; Gong, Qiaoke; Owens, Trevor

2002-01-01

Crosslinking CD40 induces normal B-cells to proliferate and differentiate but causes many tumor cell lines to undergo apoptosis. As p53 is required for many apoptotic pathways, we analyzed the effects of CD40 ligation and their correlation with p53 function in four murine B-lymphoma lines. A20...... of detectable p21 mRNA in A20 and M12 cells. P21 mRNA was increased to detectable levels in M12 cells upon CD40 ligation; however, blocking this effect with the p53 inhibitor pifithrin had no effect on CD40-mediated apoptosis. Sequencing showed that p53 in A20 and M12 cells contained point mutations leading...... to amino acid substitutions in DNA binding regions, but was unmutated in WEHI231 and WEHI 279. These results suggest that CD40-mediated apoptosis can occur in the absence of functional p53....

Nephropathy in type 1 diabetes is associated with increased circulating activated platelets and platelet hyperreactivity

DEFF Research Database (Denmark)

Tarnow, Inge; Michelson, Alan D.; Barnard, Marc R.

2009-01-01

Patients with diabetes mellitus (DM) have increased platelet activation compared to non-diabetic controls. Platelet hyperreactivity has been associated with adverse cardiovascular outcomes in Type 2 DM, and with diabetic nephropathy. We investigated the relationship between platelet activation...... and nephropathy in Type 1 DM. Patients with Type 1 DM and diabetic nephropathy (n = 35), age- and sex-matched Type 1 DM patients with persistent normoalbuminuria (n = 51), and healthy age- and sex-matched controls (n = 30) were studied. Platelet surface P-selectin, platelet surface activated GPIIb/IIIa, monocyte...... controls (P = 0.0075). There were no differences between groups in activated GPIIb/IIIa or in response to TRAP at any end-point. More patients with nephropathy received aspirin (71.4%) compared to normoalbuminuric patients (27.4%) (P Type 1 diabetic nephropathy, as compared with normoalbuminuria...

Platelets of patients with chronic kidney disease demonstrate deficient platelet reactivity in vitro

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van Bladel Esther R

2012-09-01

Full Text Available Abstract Background In patients with chronic kidney disease studies focusing on platelet function and properties often are non-conclusive whereas only few studies use functional platelet tests. In this study we evaluated a recently developed functional flow cytometry based assay for the analysis of platelet function in chronic kidney disease. Methods Platelet reactivity was measured using flow cytometric analysis. Platelets in whole blood were triggered with different concentrations of agonists (TRAP, ADP, CRP. Platelet activation was quantified with staining for P-selectin, measuring the mean fluorescence intensity. Area under the curve and the concentration of half-maximal response were determined. Results We studied 23 patients with chronic kidney disease (9 patients with cardiorenal failure and 14 patients with end stage renal disease and 19 healthy controls. Expression of P-selectin on the platelet surface measured as mean fluorescence intensity was significantly less in chronic kidney disease patients compared to controls after maximal stimulation with TRAP (9.7 (7.9-10.8 vs. 11.4 (9.2-12.2, P = 0.032, ADP (1.6 (1.2-2.1 vs. 2.6 (1.9-3.5, P = 0.002 and CRP (9.2 (8.5-10.8 vs. 11.5 (9.5-12.9, P = 0.004. Also the area under the curve was significantly different. There was no significant difference in half-maximal response between both groups. Conclusion In this study we found that patients with chronic kidney disease show reduced platelet reactivity in response of ADP, TRAP and CRP compared to controls. These results contribute to our understanding of the aberrant platelet function observed in patients with chronic kidney disease and emphasize the significance of using functional whole blood platelet activation assays.

Thrombopoietin contributes to enhanced platelet activation in patients with unstable angina.

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Lupia, Enrico; Bosco, Ornella; Bergerone, Serena; Dondi, Anna Erna; Goffi, Alberto; Oliaro, Elena; Cordero, Marco; Del Sorbo, Lorenzo; Trevi, Giampaolo; Montrucchio, Giuseppe

2006-12-05

We sought to investigate the potential role of elevated levels of thrombopoietin (TPO) in platelet activation during unstable angina (UA). Thrombopoietin is a humoral growth factor that does not induce platelet aggregation per se, but primes platelet activation in response to several agonists. No data concerning its contribution to platelet function abnormalities described in patients with UA are available. We studied 15 patients with UA and, as controls, 15 patients with stable angina (SA) and 15 healthy subjects. We measured TPO and C-reactive protein (CRP), as well as monocyte-platelet binding and the platelet expression of P-selectin and of the TPO receptor, c-Mpl. The priming activity of patient or control plasma on platelet aggregation and monocyte-platelet binding and the role of TPO in this effect also were studied. Patients with UA showed higher circulating TPO levels, as well as increased monocyte-platelet binding, platelet P-selectin expression, and CRP levels, than those with SA and healthy control subjects. The UA patients also showed reduced platelet expression of the TPO receptor, c-Mpl. In vitro, the plasma from UA patients, but not from SA patients or healthy controls, primed platelet aggregation and monocyte-platelet binding, which were both reduced when an inhibitor of TPO was used. Thrombopoietin may enhance platelet activation in the early phases of UA, potentially participating in the pathogenesis of acute coronary syndromes.

Abnormal megakaryocyte development and platelet function in Nbeal2(-/-) mice.

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Kahr, Walter H A; Lo, Richard W; Li, Ling; Pluthero, Fred G; Christensen, Hilary; Ni, Ran; Vaezzadeh, Nima; Hawkins, Cynthia E; Weyrich, Andrew S; Di Paola, Jorge; Landolt-Marticorena, Carolina; Gross, Peter L

2013-11-07

Gray platelet syndrome (GPS) is an inherited bleeding disorder associated with macrothrombocytopenia and α-granule-deficient platelets. GPS has been linked to loss of function mutations in NEABL2 (neurobeachin-like 2), and we describe here a murine GPS model, the Nbeal2(-/-) mouse. As in GPS, Nbeal2(-/-) mice exhibit splenomegaly, macrothrombocytopenia, and a deficiency of platelet α-granules and their cargo, including von Willebrand factor (VWF), thrombospondin-1, and platelet factor 4. The platelet α-granule membrane protein P-selectin is expressed at 48% of wild-type levels and externalized upon platelet activation. The presence of P-selectin and normal levels of VPS33B and VPS16B in Nbeal2(-/-) platelets suggests that NBEAL2 acts independently of VPS33B/VPS16B at a later stage of α-granule biogenesis. Impaired Nbeal2(-/-) platelet function was shown by flow cytometry, platelet aggregometry, bleeding assays, and intravital imaging of laser-induced arterial thrombus formation. Microscopic analysis detected marked abnormalities in Nbeal2(-/-) bone marrow megakaryocytes, which when cultured showed delayed maturation, decreased survival, decreased ploidy, and developmental abnormalities, including abnormal extracellular distribution of VWF. Our results confirm that α-granule secretion plays a significant role in platelet function, and they also indicate that abnormal α-granule formation in Nbeal2(-/-) mice has deleterious effects on megakaryocyte survival, development, and platelet production.

Effect of Clopidogrel on Platelet CD Markers in Normal Individuals and in Patients with Untreated Type 2 Diabetes Mellitus

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Saboor, M.; Moinuddin, M.; Ilyas, S.

2015-01-01

The objective of this study was to evaluate the effect of clopidogrel response in patients with untreated type 2 diabetes mellitus as compared with normal individuals. One hundred and seven subjects i.e. 32 normal and 75 patients with untreated type 2 diabetes mellitus were enrolled in this study. In the first step, normal subjects as well as diabetic patients were selected and tested for various laboratory parameters and platelets flow cytometry. In the second step, an antiplatelet drug (clopidogrel) was administered for 10 days to each individual enrolled in the study. After 10 days blood samples were collected for platelets flow cytometry. CD41 and CD61 did not show any change after the administration of clopidogrel in resting and activated platelets. CD63 and CD62p positivity was increased in normal and in diabetic patients' platelets after activation with ADP before clopidogrel. It was decreased in normal resting and ADP stimulated platelets after clopidogrel treatment. CD63 and CD62p positivity in resting and ADP stimulated patients platelets was also decreased after clopidogrel treatment. The change was, however, not as marked as in normal subjects. (author)

Selectins mediate small cell lung cancer systemic metastasis.

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Franziska Heidemann

Full Text Available Metastasis formation is the major reason for the extremely poor prognosis in small cell lung cancer (SCLC patients. The molecular interaction partners regulating metastasis formation in SCLC are largely unidentified, however, from other tumor entities it is known that tumor cells use the adhesion molecules of the leukocyte adhesion cascade to attach to the endothelium at the site of the future metastasis. Using the human OH-1 SCLC line as a model, we found that these cells expressed E- and P-selectin binding sites, which could be in part attributed to the selectin binding carbohydrate motif sialyl Lewis A. In addition, protein backbones known to carry these glycotopes in other cell lines including PSGL-1, CD44 and CEA could be detected in in vitro and in vivo grown OH1 SCLC cells. By intravital microscopy of murine mesenterial vasculature we could capture SCLC cells while rolling along vessel walls demonstrating that SCLC cells mimic leukocyte rolling behavior in terms of selectin and selectin ligand interaction in vivo indicating that this mechanism might indeed be important for SCLC cells to seed distant metastases. Accordingly, formation of spontaneous distant metastases was reduced by 50% when OH-1 cells were xenografted into E-/P-selectin-deficient mice compared with wild type mice (p = 0.0181. However, as metastasis formation was not completely abrogated in selectin deficient mice, we concluded that this adhesion cascade is redundant and that other molecules of this cascade mediate metastasis formation as well. Using several of these adhesion molecules as interaction partners presumably make SCLC cells so highly metastatic.

p62 regulates CD40-mediated NFκB activation in macrophages through interaction with TRAF6

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Seibold, Kristina; Ehrenschwender, Martin, E-mail: martin.ehrenschwender@ukr.de

2015-08-14

CD40 is a member of the tumor necrosis factor (TNF) receptor family. Activation-induced recruitment of adapter proteins, so-called TNF-receptor-associated factors (TRAFs) to the cytoplasmic tail of CD40 triggers signaling cascades important in the immune system, but has also been associated with excessive inflammation in diseases such as atherosclerosis and rheumatoid arthritis. Especially, pro-inflammatory nuclear factor κB (NFκB) signaling emanating from CD40-associated TRAF6 appears to be a key pathogenic driving force. Consequently, targeting the CD40-TRAF6 interaction is emerging as a promising therapeutic strategy, but the underlying molecular machinery of this signaling axis is to date poorly understood. Here, we identified the multifunctional adaptor protein p62 as a critical regulator in CD40-mediated NFκB signaling via TRAF6. CD40 activation triggered formation of a TRAF6-p62 complex. Disturbing this interaction tremendously reduced CD40-mediated NFκB signaling in macrophages, while TRAF6-independent signaling pathways remained unaffected. This highlights p62 as a potential target in hyper-inflammatory, CD40-associated pathologies. - Highlights: • CD40 activation triggers interaction of the adapter protein TRAF6 with p62. • TRAF6-p62 interaction regulates CD40-mediated NFκB signaling in macrophages. • Defective TRAF6-p62 interaction reduces CD40-mediated NFκB activation in macrophages.

Efficient removal of platelets from peripheral blood progenitor cell products using a novel micro-chip based acoustophoretic platform.

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Josefina Dykes

Full Text Available BACKGROUND: Excessive collection of platelets is an unwanted side effect in current centrifugation-based peripheral blood progenitor cell (PBPC apheresis. We investigated a novel microchip-based acoustophoresis technique, utilizing ultrasonic standing wave forces for the removal of platelets from PBPC products. By applying an acoustic standing wave field onto a continuously flowing cell suspension in a micro channel, cells can be separated from the surrounding media depending on their physical properties. STUDY DESIGN AND METHODS: PBPC samples were obtained from patients (n = 15 and healthy donors (n = 6 and sorted on an acoustophoresis-chip. The acoustic force was set to separate leukocytes from platelets into a target fraction and a waste fraction, respectively. The PBPC samples, the target and the waste fractions were analysed for cell recovery, purity and functionality. RESULTS: The median separation efficiency of leukocytes to the target fraction was 98% whereas platelets were effectively depleted by 89%. PBPC samples and corresponding target fractions were similar in the percentage of CD34+ hematopoetic progenitor/stem cells as well as leukocyte/lymphocyte subset distributions. Median viability was 98%, 98% and 97% in the PBPC samples, the target and the waste fractions, respectively. Results from hematopoietic progenitor cell assays indicated a preserved colony-forming ability post-sorting. Evaluation of platelet activation by P-selectin (CD62P expression revealed a significant increase of CD62P+ platelets in the target (19% and waste fractions (20%, respectively, compared to the PBPC input samples (9%. However, activation was lower when compared to stored blood bank platelet concentrates (48%. CONCLUSION: Acoustophoresis can be utilized to efficiently deplete PBPC samples of platelets, whilst preserving the target stem/progenitor cell and leukocyte cell populations, cell viability and progenitor cell colony-forming ability

Platelet-derived growth factor inhibits platelet activation in heparinized whole blood.

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Selheim, F; Holmsen, H; Vassbotn, F S

1999-08-15

We previously have demonstrated that human platelets have functionally active platelet-derived growth factor alpha-receptors. Studies with gel-filtered platelets showed that an autocrine inhibition pathway is transduced through this tyrosine kinase receptor during platelet activation. The physiological significance of this inhibitory effect of platelet-derived growth factor on gel-filtered platelets activation is, however, not known. In the present study, we investigated whether platelet-derived growth factor inhibits platelet activation under more physiological conditions in heparinized whole blood, which represents a more physiological condition than gel-filtered platelets. Using flow cytometric assays, we demonstrate here that platelet-derived growth factor inhibits thrombin-, thrombin receptor agonist peptide SFLLRN-, and collagen-induced platelet aggregation and shedding of platelet-derived microparticles from the platelet plasma membrane during platelet aggregation in stirred heparinized whole blood. The inhibitory effect of platelet-derived growth factor was dose dependent. However, under nonaggregating conditions (no stirring), we could not demonstrate any significant effect of platelet-derived growth factor on thrombin- and thrombin receptor agonist peptide-induced platelet surface expression of P-selectin. Our results demonstrate that platelet-derived growth factor appears to be a true antithrombotic agent only under aggregating conditions in heparinized whole blood.

P-selectin targeting to secretory lysosomes of Rbl-2H3 cells

OpenAIRE

Kaur, J.; Cutler, D. F.

2002-01-01

The biogenesis of secretory lysosomes, which combine characteristics of both lysosomes and secretory granules, is currently of high interest. In particular, it is not clear whether delivery of membrane proteins to the secretory lysosome requires lysosomal, secretory granule, or some novel targeting determinants. Heterologous expression of P-selectin has established that this membrane protein contains targeting signals for both secretory granules and lysosomes. P-selectin is therefore an ideal...

P-selectin in preterm infants suffering necrotizing enterocolitis ...

African Journals Online (AJOL)

All neonates were subjected to perinatal history, clinical examination, routine investigations (CBC, plain X-ray and abdominal ultrasonography (US), arterial blood gases and serum bicarbonate, serum sodium, CRP and blood culture), and measurement of blood P-selectin by direct immunofluorescent staining. Results: ...

The pro-inflammatory effects of platelet contamination in plasma and mitigation strategies for avoidance

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Bercovitz, R. S.; Kelher, M. R.; Khan, S. Y.; Land, K. J.; Berry, T. H.; Silliman, C. C.

2013-01-01

Background and Objectives Plasma and platelet concentrates are disproportionately implicated in transfusion-related acute lung injury (TRALI). Platelet-derived pro-inflammatory mediators, including soluble CD40 ligand (sCD40L), accumulate during storage. We hypothesized that platelet contamination induces sCD40L generation that causes neutrophil [polymorphonuclear leucocyte (PMN)] priming and PMN-mediated cytotoxicity. Materials and Methods Plasma was untreated, centrifuged (12 500 g) or separated from leucoreduced whole blood (WBLR) prior to freezing. Platelet counts and sCD40L concentrations were measured 1–5 days post-thaw. The plasma was assayed for PMN priming activity and was used in a two-event in vitro model of PMN-mediated human pulmonary microvascular endothelial cell (HMVEC) cytotoxicity. Results Untreated plasma contained 42 ± 4.2 × 103/μl platelets, which generated sCD40L accumulation (1.6-eight-fold vs. controls). Priming activity and HMVEC cytotoxicity were directly proportional to sCD40L concentration. WBLR and centrifugation reduced platelet and sCD40L contamination, abrogating the pro-inflammatory potential. Conclusion Platelet contamination causes sCD40L accumulation in stored plasma that may contribute to TRALI. Platelet reduction is potentially the first TRALI mitigation effort in plasma manufacturing. PMID:22092073

Gallic Acid Attenuates Platelet Activation and Platelet-Leukocyte Aggregation: Involving Pathways of Akt and GSK3β

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Chang, Shih-Sheng; Lee, Viola S. Y.; Tseng, Yu-Lun; Chang, Kuan-Cheng; Chen, Kuen-Bao; Chen, Yuh-Lien; Li, Chi-Yuan

2012-01-01

Platelet activation and its interaction with leukocytes play an important role in atherothrombosis. Cardiovascular diseases resulted from atherothrombosis remain the major causes of death worldwide. Gallic acid, a major constituent of red wine and tea, has been believed to have properties of cardiovascular protection, which is likely to be related to its antioxidant effects. Nonetheless, there were few and inconsistent data regarding the effects of gallic acid on platelet function. Therefore, we designed this in vitro study to determine whether gallic acid could inhibit platelet activation and the possible mechanisms. From our results, gallic acid could concentration-dependently inhibit platelet aggregation, P-selectin expression, and platelet-leukocyte aggregation. Gallic acid prevented the elevation of intracellular calcium and attenuated phosphorylation of PKCα/p38 MAPK and Akt/GSK3β on platelets stimulated by the stimulants ADP or U46619. This is the first mechanistic explanation for the inhibitory effects on platelets from gallic acid. PMID:22811749

Gallic Acid Attenuates Platelet Activation and Platelet-Leukocyte Aggregation: Involving Pathways of Akt and GSK3β

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Shih-Sheng Chang

2012-01-01

Full Text Available Platelet activation and its interaction with leukocytes play an important role in atherothrombosis. Cardiovascular diseases resulted from atherothrombosis remain the major causes of death worldwide. Gallic acid, a major constituent of red wine and tea, has been believed to have properties of cardiovascular protection, which is likely to be related to its antioxidant effects. Nonetheless, there were few and inconsistent data regarding the effects of gallic acid on platelet function. Therefore, we designed this in vitro study to determine whether gallic acid could inhibit platelet activation and the possible mechanisms. From our results, gallic acid could concentration-dependently inhibit platelet aggregation, P-selectin expression, and platelet-leukocyte aggregation. Gallic acid prevented the elevation of intracellular calcium and attenuated phosphorylation of PKCα/p38 MAPK and Akt/GSK3β on platelets stimulated by the stimulants ADP or U46619. This is the first mechanistic explanation for the inhibitory effects on platelets from gallic acid.

Using affinity capillary electrophoresis and computational models for binding studies of heparinoids with p-selectin and other proteins.

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Mozafari, Mona; Balasupramaniam, Shantheya; Preu, Lutz; El Deeb, Sami; Reiter, Christian G; Wätzig, Hermann

2017-06-01

A fast and precise affinity capillary electrophoresis (ACE) method has been developed and applied for the investigation of the binding interactions between P-selectin and heparinoids as potential P-selectin inhibitors in the presence and absence of calcium ions. Furthermore, model proteins and vitronectin were used to appraise the binding behavior of P-selectin. The normalized mobility ratios (∆R/R f ), which provided information about the binding strength and the overall charge of the protein-ligand complex, were used to evaluate the binding affinities. It was found that P-selectin interacts more strongly with heparinoids in the presence of calcium ions. P-selectin was affected by heparinoids at the concentration of 3 mg/L. In addition, the results of the ACE experiments showed that among other investigated proteins, albumins and vitronectin exhibited strong interactions with heparinoids. Especially with P-selectin and vitronectin, the interaction may additionally induce conformational changes. Subsequently, computational models were applied to interpret the ACE experiments. Docking experiments explained that the binding of heparinoids on P-selectin is promoted by calcium ions. These docking models proved to be particularly well suited to investigate the interaction of charged compounds, and are therefore complementary to ACE experiments. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Abnormal megakaryocyte development and platelet function in Nbeal2−/− mice

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Lo, Richard W.; Li, Ling; Pluthero, Fred G.; Christensen, Hilary; Ni, Ran; Vaezzadeh, Nima; Hawkins, Cynthia E.; Weyrich, Andrew S.; Di Paola, Jorge; Landolt-Marticorena, Carolina; Gross, Peter L.

2013-01-01

Gray platelet syndrome (GPS) is an inherited bleeding disorder associated with macrothrombocytopenia and α-granule-deficient platelets. GPS has been linked to loss of function mutations in NEABL2 (neurobeachin-like 2), and we describe here a murine GPS model, the Nbeal2−/− mouse. As in GPS, Nbeal2−/− mice exhibit splenomegaly, macrothrombocytopenia, and a deficiency of platelet α-granules and their cargo, including von Willebrand factor (VWF), thrombospondin-1, and platelet factor 4. The platelet α-granule membrane protein P-selectin is expressed at 48% of wild-type levels and externalized upon platelet activation. The presence of P-selectin and normal levels of VPS33B and VPS16B in Nbeal2−/− platelets suggests that NBEAL2 acts independently of VPS33B/VPS16B at a later stage of α-granule biogenesis. Impaired Nbeal2−/− platelet function was shown by flow cytometry, platelet aggregometry, bleeding assays, and intravital imaging of laser-induced arterial thrombus formation. Microscopic analysis detected marked abnormalities in Nbeal2−/− bone marrow megakaryocytes, which when cultured showed delayed maturation, decreased survival, decreased ploidy, and developmental abnormalities, including abnormal extracellular distribution of VWF. Our results confirm that α-granule secretion plays a significant role in platelet function, and they also indicate that abnormal α-granule formation in Nbeal2−/− mice has deleterious effects on megakaryocyte survival, development, and platelet production. PMID:23861251

TIM-1 glycoprotein binds the adhesion receptor P-selectin and mediates T cell trafficking during inflammation and autoimmunity

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Angiari, Stefano; Donnarumma, Tiziano; Rossi, Barbara; Dusi, Silvia; Pietronigro, Enrica; Zenaro, Elena; Della Bianca, Vittorina; Toffali, Lara; Piacentino, Gennj; Budui, Simona; Rennert, Paul; Xiao, Sheng; Laudanna, Carlo; Casasnovas, Jose M.; Kuchroo, Vijay K.; Constantin, Gabriela

2014-01-01

SUMMARY Selectins play a central role in leukocyte trafficking by mediating tethering and rolling on vascular surfaces. Here we have reported that T cell immunoglobulin and mucin domain 1 (TIM-1) is a P-selectin ligand. We have shown that human and murine TIM-1 binds to P-selectin, and that TIM-1 mediates tethering and rolling of T helper-1 (Th1) and Th17, but not Th2 and regulatory T cells on P-selectin. Th1 and Th17 cells lacking the TIM-1 mucin domain showed reduced rolling in thrombin-activated mesenteric venules and inflamed brain microcirculation. Inhibition of TIM-1 had no effect on naive T cell homing, but reduced T cell recruitment in a skin hypersensitivity model and blocked experimental autoimmune encephalomyelitis. Uniquely, the TIM-1 IgV domain was also required for P-selectin binding. Our data demonstrate that TIM-1 is a major P-selectin ligand with a specialized role in T cell trafficking during inflammatory responses and the induction of autoimmune disease. PMID:24703780

Platelets Promote Metastasis via Binding Tumor CD97 Leading to Bidirectional Signaling that Coordinates Transendothelial Migration

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Yvona Ward

2018-04-01

Full Text Available Summary: Tumor cells initiate platelet activation leading to the secretion of bioactive molecules, which promote metastasis. Platelet receptors on tumors have not been well-characterized, resulting in a critical gap in knowledge concerning platelet-promoted metastasis. We identify a direct interaction between platelets and tumor CD97 that stimulates rapid bidirectional signaling. CD97, an adhesion G protein-coupled receptor (GPCR, is an overexpressed tumor antigen in several cancer types. Purified CD97 extracellular domain or tumor cell-associated CD97 stimulated platelet activation. CD97-initiated platelet activation led to granule secretion, including the release of ATP, a mediator of endothelial junction disruption. Lysophosphatidic acid (LPA derived from platelets induced tumor invasiveness via proximal CD97-LPAR heterodimer signaling, coupling coincident tumor cell migration and vascular permeability to promote transendothelial migration. Consistent with this, CD97 was necessary for tumor cell-induced vascular permeability in vivo and metastasis formation in preclinical models. These findings support targeted blockade of tumor CD97 as an approach to ameliorate metastatic spread. : Tumor-initiated platelet activation promotes tissue invasion of cancer cells and metastasis. Ward et al. demonstrate that a common tumor-associated antigen, CD97, accounts for platelet activation and participates directly in LPA-mediated signal transduction leading to tumor cell invasion. CD97 promotes vascular extravasation and metastasis in pre-clinical models. Keywords: platelets, metastasis, transendothelial migration, circulating tumor cells, CD97, adhesion GPCR, LPA

Clinical significance of changes of serum of P-selectin, CEA and TSGF levels after operation in patients with rectal cancer

International Nuclear Information System (INIS)

Wang Zhizhong; Huang Jin

2007-01-01

Objective: To study the clinical significance of postoperative changes of serum P-selectin, CEA and TSGF levels in patients with rectal cancer. Methods: Serum CEA (with RIA), P-selectin (with ELISA), and TSGF (with biochemistry levels were determined) in 32 patients with rectal cancer both before and after operation as well as in 30 controls. Results: Before operation, the serum P-selectin, CEA and TSGF levels were significantly higher than those in controls (P < 0.01), Twenty -two of the 30 patients underwent operative therapy showed no sign of recurrence at one year and their serum P-selectin, CEA and TSGF levels dropped to within normal range. Hower in the 8 patients with recurrence, the serum levels of P-selectin, CEA and TSGF remained abnormally high. Conclusion: Serum P-selectin, CEA and TSGF levels were closely related to the diseases process of rectal cancer and were of prognostic values. (authors)

Changes in CD11b and L-selectin expression on eosinophils are mediated by human lung fibroblasts in vitro

NARCIS (Netherlands)

Spoelstra, FM; Hovenga, H; Noordhoek, JA; Postma, DS; Kauffman, HF

Eosinophilic airway infiltration is a central feature in asthma. Eosinophils recovered from bronchoalveolar fluid show an activated phenotype, e.g., increased CD11b and decreased L-selectin expression. We investigated whether lung fibroblasts are able to activate eosinophils in vitro, and if so,

Superior integrin activating capacity and higher adhesion to fibrinogen matrix in buffy coat-derived platelet concentrates (PCs) compared to PRP-PCs.

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Beshkar, Pezhman; Hosseini, Ehteramolsadat; Ghasemzadeh, Mehran

2018-02-01

Regardless of different sources, methods or devices which are applied for preparation of therapeutic platelets, these products are generally isolated from whole blood by the sedimentation techniques which are based on PRP or buffy coat (BC) separation. As a general fact, platelet preparation and storage are also associated with some deleterious changes that known as platelet storage lesion (PSL). Although these alternations in platelet functional activity are aggravated during storage, whether technical issues within preparation can affect integrin activation and platelet adhesion to fibrinogen were investigated in this study. PRP- and BC-platelet concentrates (PCs) were subjected to flowcytometry analysis to examine the expression of platelet activation marker, P-selectin as well as active confirmation of the GPIIb/IIIa (α IIb β 3 ) on day 0, 1, 3 and 5 post-storage. Platelet adhesion to fibrinogen matrix was evaluated by fluorescence microscopy. Glucose concentration and LDH activity were also measured by colorimetric methods. The increasing P-selectin expression during storage was in a reverse correlation with PAC-1 binding (r = -0.67; p = .001). PRP-PCs showed the higher level of P-selectin expression than BC-PCs, whereas the levels of PAC-1 binding and platelet adhesion to fibrinogen matrix were significantly lower in PRP-PCs. Higher levels of active confirmation of the GPIIb/IIIa in BC-PCs were also associated with greater concentration of glucose in these products. We demonstrated the superior capacities of integrin activation and adhesion to fibrinogen for BC-PCs compared to those of PRP-PCs. These findings may provide more advantages for BC method of platelet preparation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Flow cytometric immunobead assay for quantitative detection of platelet autoantibodies in immune thrombocytopenia patients.

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Zhai, Juping; Ding, Mengyuan; Yang, Tianjie; Zuo, Bin; Weng, Zhen; Zhao, Yunxiao; He, Jun; Wu, Qingyu; Ruan, Changgeng; He, Yang

2017-10-23

Platelet autoantibody detection is critical for immune thrombocytopenia (ITP) diagnosis and prognosis. Therefore, we aimed to establish a quantitative flow cytometric immunobead assay (FCIA) for ITP platelet autoantibodies evaluation. Capture microbeads coupled with anti-GPIX, -GPIb, -GPIIb, -GPIIIa and P-selectin antibodies were used to bind the platelet-bound autoantibodies complex generated from plasma samples of 250 ITP patients, 163 non-ITP patients and 243 healthy controls, a fluorescein isothiocyanate (FITC)-conjugated secondary antibody was the detector reagent and mean fluorescence intensity (MFI) signals were recorded by flow cytometry. Intra- and inter-assay variations of the quantitative FCIA assay were assessed. Comparisons of the specificity, sensitivity and accuracy between quantitative and qualitative FCIA or monoclonal antibody immobilization of platelet antigen (MAIPA) assay were performed. Finally, treatment process was monitored by our quantitative FCIA in 8 newly diagnosed ITPs. The coefficient of variations (CV) of the quantitative FCIA assay were respectively 9.4, 3.8, 5.4, 5.1 and 5.8% for anti-GPIX, -GPIb, -GPIIIa, -GPIIb and -P-selectin autoantibodies. Elevated levels of autoantibodies against platelet glycoproteins GPIX, GPIb, GPIIIa, GPIIb and P-selectin were detected by our quantitative FCIA in ITP patients compared to non-ITP patients or healthy controls. The sensitivity, specificity and accuracy of our quantitative assay were respectively 73.13, 81.98 and 78.65% when combining all 5 autoantibodies, while the sensitivity, specificity and accuracy of MAIPA assay were respectively 41.46, 90.41 and 72.81%. A quantitative FCIA assay was established. Reduced levels of platelet autoantibodies could be confirmed by our quantitative FCIA in ITP patients after corticosteroid treatment. Our quantitative assay is not only good for ITP diagnosis but also for ITP treatment monitoring.

PlA polymorphism and platelet reactivity following clopidogrel loading dose in patients undergoing coronary stent implantation.

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Angiolillo, Dominick J; Fernandez-Ortiz, Antonio; Bernardo, Esther; Alfonso, Fernando; Sabaté, Manel; Fernández, Cristina; Stranieri, Chiara; Trabetti, Elisabetta; Pignatti, Pier Franco; Macaya, Carlos

2004-01-01

The PlA polymorphism (Leu33Pro) of the platelet glycoprotein (GP) IIIa gene has been suggested to play an important role in coronary thrombosis. In vitro studies have shown differences for this polymorphism in platelet sensitivity towards antiplatelet drugs (aspirin and abciximab), suggesting a pharmacogenetic modulation. The aim of the study was to assess the modulatory effect of the PlA polymorphism on clopidogrel-induced antiplatelet effects in 38 patients undergoing coronary stent implantation receiving a 300 mg clopidogrel loading-dose. Platelet reactivity was assessed as GPIIb/IIIa activation and P-selectin expression in platelets stimulated with 2 micromol/l adenosine diphosphate using whole blood flow cytometry. The distribution of the homozygous PlA1/A1 and heterozygous PlA1/A2 genotypes were 74 and 26%, respectively. PlA2 carriers had a higher degree of GPIIb/IIIa activation (P = 0.05) and P-selectin expression (P = 0.02) during the overall study time course and a lower antiplatelet effect to a 300 mg clopidogrel loading-dose up to 24 h following intervention (P < 0.05). In conclusion, the Pl polymorphism of the GPIIIa gene modulates platelet reactivity towards clopidogrel front loading in patients undergoing coronary stenting. This suggests the need for individualized antithrombotic regimens to optimally inhibit platelet reactivity. Copyright 2004 Lippincott Williams and Wilkins

PPARγ ligands decrease hydrostatic pressure-induced platelet aggregation and proinflammatory activity.

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Fang Rao

Full Text Available Hypertension is known to be associated with platelet overactivity, but the direct effects of hydrostatic pressure on platelet function remain unclear. The present study sought to investigate whether elevated hydrostatic pressure is responsible for platelet activation and to address the potential role of peroxisome proliferator-activated receptor-γ (PPARγ. We observed that hypertensive patients had significantly higher platelet volume and rate of ADP-induced platelets aggregation compared to the controls. In vitro, Primary human platelets were cultured under standard (0 mmHg or increased (120, 180, 240 mmHg hydrostatic pressure for 18 h. Exposure to elevated pressure was associated with morphological changes in platelets. Platelet aggregation and PAC-1 (the active confirmation of GPIIb/IIIa binding were increased, CD40L was translocated from cytoplasm to the surface of platelet and soluble CD40L (sCD40L was released into the medium in response to elevated hydrostatic pressure (180 and 240 mmHg. The PPARγ activity was up-regulated as the pressure was increased from 120 mmHg to 180 mmHg. Pressure-induced platelet aggregation, PAC-1 binding, and translocation and release of CD40L were all attenuated by the PPARγ agonist Thiazolidinediones (TZDs. These results demonstrate that platelet activation and aggregation are increased by exposure to elevated pressure and that PPARγ may modulate platelet activation induced by high hydrostatic pressure.

PPARγ ligands decrease hydrostatic pressure-induced platelet aggregation and proinflammatory activity.

Science.gov (United States)

Rao, Fang; Yang, Ren-Qiang; Chen, Xiao-Shu; Xu, Jin-Song; Fu, Hui-Min; Su, Hai; Wang, Ling

2014-01-01

Hypertension is known to be associated with platelet overactivity, but the direct effects of hydrostatic pressure on platelet function remain unclear. The present study sought to investigate whether elevated hydrostatic pressure is responsible for platelet activation and to address the potential role of peroxisome proliferator-activated receptor-γ (PPARγ). We observed that hypertensive patients had significantly higher platelet volume and rate of ADP-induced platelets aggregation compared to the controls. In vitro, Primary human platelets were cultured under standard (0 mmHg) or increased (120, 180, 240 mmHg) hydrostatic pressure for 18 h. Exposure to elevated pressure was associated with morphological changes in platelets. Platelet aggregation and PAC-1 (the active confirmation of GPIIb/IIIa) binding were increased, CD40L was translocated from cytoplasm to the surface of platelet and soluble CD40L (sCD40L) was released into the medium in response to elevated hydrostatic pressure (180 and 240 mmHg). The PPARγ activity was up-regulated as the pressure was increased from 120 mmHg to 180 mmHg. Pressure-induced platelet aggregation, PAC-1 binding, and translocation and release of CD40L were all attenuated by the PPARγ agonist Thiazolidinediones (TZDs). These results demonstrate that platelet activation and aggregation are increased by exposure to elevated pressure and that PPARγ may modulate platelet activation induced by high hydrostatic pressure.

COMPARATIVE ANALYSIS OF SOLUBLE OF CD40 LIGAND LEVELS IN HEART RECIPIENTS TREATED WITH CYCLOSPORINE A AND TACROLIMUS

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O. P. Shevchenko

2012-01-01

Full Text Available Soluble form of CD40L is platelet activating factor, which is a marker of inflammation and thrombosis. Elevated levels of sCD40L before the heart transplantation are associated with the risk of early development of cardiova- scular complications. The study included 54 patients who had received heart transplants. All recipients received a triple heart immu- nosuppressive therapy, including methylprednisolone, mycophenolate mofetil and cyclosporine A (20 recipients or methylprednisolone, mycophenolate mofetil and tacrolimus (34 recipients. Patients were not differed by age, gender, etiology of heart failure before heart transplantation (p > 0,05. In the first group of transplant recipients, the relative risk of cardiovascular events with high sCD40L levels before transplantation was 3 2 (95% CI 1,4; 12,0. In the second group of recipients, respectively, 2.69 (95% CI 1,1; 8,5. SCD40L level after heart transplan- tation was significantly higher for patients receiving cyclosporine (P < 0.05. Increasing concentrations of sCD40L are associated with a higher incidence of cardiovascular complications. 

Flavanols and Platelet Reactivity

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Debra A. Pearson

2005-01-01

Full Text Available Platelet activity and platelet-endothelial cell interactions are important in the acute development of thrombosis, as well as in the pathogenesis of cardiovascular disease. An increasing number of foods have been reported to have platelet-inhibitory actions, and research with a number of flavanol-rich foods, including, grape juice, cocoa and chocolate, suggests that these foods may provide some protection against thrombosis. In the present report, we review a series of in vivo studies on the effects of flavanol-rich cocoa and chocolate on platelet activation and platelet-dependent primary hemostasis. Consumption of flavanol-rich cocoa inhibited several measures of platelet activity including, epinephrine- and ADP-induced glycoprotein (GP IIb/IIIa and P-Selectin expression, platelet microparticle formation, and epinephrine-collagen and ADP-collagen induced primary hemostasis. The epinephrine-induced inhibitory effects on GP IIb/IIIa and primary hemostasis were similar to, though less robust than those associated with the use of low dose (81 mg aspirin. These data, coupled with information from other studies, support the concept that flavanols present in cocoa and chocolate can modulate platelet function through a multitude of pathways.

Detection of early stage atherosclerotic plaques using PET and CT fusion imaging targeting P-selectin in low density lipoprotein receptor-deficient mice

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Nakamura, Ikuko, E-mail: nakamuri@riken.jp [RIKEN Center for Molecular Imaging Science, Kobe (Japan); Department of Cardiovascular Medicine, Saga University, Saga (Japan); Hasegawa, Koki [RIKEN Center for Molecular Imaging Science, Kobe (Japan); Department of Pathology and Experimental Medicine, Kumamoto University, Kumamoto (Japan); Wada, Yasuhiro [RIKEN Center for Molecular Imaging Science, Kobe (Japan); Hirase, Tetsuaki; Node, Koichi [Department of Cardiovascular Medicine, Saga University, Saga (Japan); Watanabe, Yasuyoshi, E-mail: yywata@riken.jp [RIKEN Center for Molecular Imaging Science, Kobe (Japan)

2013-03-29

Highlights: ► P-selectin regulates leukocyte recruitment as an early stage event of atherogenesis. ► We developed an antibody-based molecular imaging probe targeting P-selectin for PET. ► This is the first report on successful PET imaging for delineation of P-selectin. ► P-selectin is a candidate target for atherosclerotic plaque imaging by clinical PET. -- Abstract: Background: Sensitive detection and qualitative analysis of atherosclerotic plaques are in high demand in cardiovascular clinical settings. The leukocyte–endothelial interaction mediated by an adhesion molecule P-selectin participates in arterial wall inflammation and atherosclerosis. Methods and results: A {sup 64}Cu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid conjugated anti-P-selectin monoclonal antibody ({sup 64}Cu-DOTA-anti-P-selectin mAb) probe was prepared by conjugating an anti-P-selectin monoclonal antibody with DOTA followed by {sup 64}Cu labeling. Thirty-six hours prior to PET and CT fusion imaging, 3 MBq of {sup 64}Cu-DOTA-anti-P-selectin mAb was intravenously injected into low density lipoprotein receptor-deficient Ldlr-/- mice. After a 180 min PET scan, autoradiography and biodistribution of {sup 64}Cu-DOTA-anti-P-selectin monoclonal antibody was examined using excised aortas. In Ldlr-/- mice fed with a high cholesterol diet for promotion of atherosclerotic plaque development, PET and CT fusion imaging revealed selective and prominent accumulation of the probe in the aortic root. Autoradiography of aortas that demonstrated probe uptake into atherosclerotic plaques was confirmed by Oil red O staining for lipid droplets. In Ldlr-/- mice fed with a chow diet to develop mild atherosclerotic plaques, probe accumulation was barely detectable in the aortic root on PET and CT fusion imaging. Probe biodistribution in aortas was 6.6-fold higher in Ldlr-/- mice fed with a high cholesterol diet than in those fed with a normal chow diet. {sup 64}Cu-DOTA-anti-P-selectin m

Low-grade endotoxemia, gut permeability and platelet activation in patients with impaired fasting glucose.

Science.gov (United States)

Carnevale, R; Pastori, D; Nocella, C; Cammisotto, V; Baratta, F; Del Ben, M; Angelico, F; Sciarretta, S; Bartimoccia, S; Novo, M; Targher, G; Violi, F

2017-10-01

Impaired fasting glucose (IFG) is associated with an increased risk of cardiovascular disease but the underlying mechanisms are still unclear. Aim of the study was to investigate the interplay between platelet activation, lipopolysaccharides (LPS) and markers of oxidative stress in patients with IFG and control subjects. We performed a cross-sectional study including 35 patients with IFG and 35 control subjects who were well comparable for age, sex, body mass index and smoking history. Serum levels of LPS, zonulin (a marker of gut permeability), oxidized LDL and plasma levels of soluble P-selectin, were measured. Patients with IFG had significantly higher levels of sP-selectin, LPS, zonulin and oxLDL compared to control subjects. The IFG status (beta coefficient: 0.518, p zonulin (r = 0.521, p = 0.001); this association was confirmed at multivariable analysis (beta coefficient: 0.512, p = 0.007). Our study provides evidence that patients with IFG have increased platelet activation, and suggests LPS as a potential trigger for in vivo platelet activation in this patient population. Copyright © 2017. Published by Elsevier B.V.

Increased platelet reactivity is associated with circulating platelet-monocyte complexes and macrophages in human atherosclerotic plaques.

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Bert Rutten

Full Text Available Platelet reactivity, platelet binding to monocytes and monocyte infiltration play a detrimental role in atherosclerotic plaque progression. We investigated whether platelet reactivity was associated with levels of circulating platelet-monocyte complexes (PMCs and macrophages in human atherosclerotic carotid plaques.Platelet reactivity was determined by measuring platelet P-selectin expression after platelet stimulation with increasing concentrations of adenosine diphosphate (ADP, in two independent cohorts: the Circulating Cells cohort (n = 244 and the Athero-Express cohort (n = 91. Levels of PMCs were assessed by flow cytometry in blood samples of patients who were scheduled for percutaneous coronary intervention (Circulating Cells cohort. Monocyte infiltration was semi-quantitatively determined by histological examination of atherosclerotic carotid plaques collected during carotid endarterectomy (Athero-Express cohort.We found increased platelet reactivity in patients with high PMCs as compared to patients with low PMCs (median (interquartile range: 4153 (1585-11267 area under the curve (AUC vs. 9633 (3580-21565 AUC, P<0.001. Also, we observed increased platelet reactivity in patients with high macrophage levels in atherosclerotic plaques as compared to patients with low macrophage levels in atherosclerotic plaques (mean ± SD; 8969 ± 3485 AUC vs. 7020 ± 3442 AUC, P = 0.02. All associations remained significant after adjustment for age, sex and use of drugs against platelet activation.Platelet reactivity towards ADP is associated with levels of PMCs and macrophages in human atherosclerotic carotid plaques.

Effects of simvastatin/ezetimibe on microparticles, endothelial progenitor cells and platelet aggregation in subjects with coronary heart disease under antiplatelet therapy

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Camargo, L.M.; França, C.N.; Izar, M.C.; Bianco, H.T.; Lins, L.S.; Barbosa, S.P.; Pinheiro, L.F.; Fonseca, F.A.H. [Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Medicina, São Paulo, SP, Brasil, Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil)

2014-04-15

It is not known whether the addition of ezetimibe to statins adds cardiovascular protection beyond the expected changes in lipid levels. Subjects with coronary heart disease were treated with four consecutive 1-week courses of therapy (T) and evaluations. The courses were: T1, 100 mg aspirin alone; T2, 100 mg aspirin and 40 mg simvastatin/10 mg ezetimibe; T3, 40 mg simvastatin/10 mg ezetimibe, and 75 mg clopidogrel (300 mg initial loading dose); T4, 75 mg clopidogrel alone. Platelet aggregation was examined in whole blood. Endothelial microparticles (CD51), platelet microparticles (CD42/CD31), and endothelial progenitor cells (CD34/CD133; CDKDR/CD133, or CD34/KDR) were quantified by flow cytometry. Endothelial function was examined by flow-mediated dilation. Comparisons between therapies revealed differences in lipids (T2 and T3P<0.002 for all), as well as for endothelial function (T2>T1 and T4, P=0.001). Decreased platelet aggregation was observed after aspirin (arachidonic acid, T1P=0.034) and clopidogrel (adenosine, T3 and T4P<0.0001) therapy. Simvastatin/ezetimibe diphosphate did not change platelet aggregation, the amount of circulating endothelial and platelet microparticles, or endothelial progenitor cells. Cardiovascular protection following therapy with simvastatin/ezetimibe seems restricted to lipid changes and improvement of endothelial function not affecting the release of microparticles, mobilization of endothelial progenitor cells or decreased platelet aggregation.

Effects of simvastatin/ezetimibe on microparticles, endothelial progenitor cells and platelet aggregation in subjects with coronary heart disease under antiplatelet therapy

International Nuclear Information System (INIS)

Camargo, L.M.; França, C.N.; Izar, M.C.; Bianco, H.T.; Lins, L.S.; Barbosa, S.P.; Pinheiro, L.F.; Fonseca, F.A.H.

2014-01-01

It is not known whether the addition of ezetimibe to statins adds cardiovascular protection beyond the expected changes in lipid levels. Subjects with coronary heart disease were treated with four consecutive 1-week courses of therapy (T) and evaluations. The courses were: T1, 100 mg aspirin alone; T2, 100 mg aspirin and 40 mg simvastatin/10 mg ezetimibe; T3, 40 mg simvastatin/10 mg ezetimibe, and 75 mg clopidogrel (300 mg initial loading dose); T4, 75 mg clopidogrel alone. Platelet aggregation was examined in whole blood. Endothelial microparticles (CD51), platelet microparticles (CD42/CD31), and endothelial progenitor cells (CD34/CD133; CDKDR/CD133, or CD34/KDR) were quantified by flow cytometry. Endothelial function was examined by flow-mediated dilation. Comparisons between therapies revealed differences in lipids (T2 and T3P<0.002 for all), as well as for endothelial function (T2>T1 and T4, P=0.001). Decreased platelet aggregation was observed after aspirin (arachidonic acid, T1P=0.034) and clopidogrel (adenosine, T3 and T4P<0.0001) therapy. Simvastatin/ezetimibe diphosphate did not change platelet aggregation, the amount of circulating endothelial and platelet microparticles, or endothelial progenitor cells. Cardiovascular protection following therapy with simvastatin/ezetimibe seems restricted to lipid changes and improvement of endothelial function not affecting the release of microparticles, mobilization of endothelial progenitor cells or decreased platelet aggregation

Comparison of VerifyNow-P2Y12 test and Flow Cytometry for monitoring individual platelet response to clopidogrel. What is the cut-off value for identifying patients who are low responders to clopidogrel therapy?

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Castelli Alfredo

2009-05-01

Full Text Available Abstract Background Dual anti-platelet therapy with aspirin and a thienopyridine (DAT is used to prevent stent thrombosis after percutaneous coronary intervention (PCI. Low response to clopidogrel therapy (LR occurs, but laboratory tests have a controversial role in the identification of this condition. Methods We studied LR in patients with stable angina undergoing elective PCI, all on DAT for at least 7 days, by comparing: 1 Flow cytometry (FC to measure platelet membrane expression of P-selectin (CD62P and PAC-1 binding following double stimulation with ADP and collagen type I either in the presence of prostaglandin (PG E1; 2 VerifyNow-P2Y12 test, in which results are reported as absolute P2Y12-Reaction-Units (PRU or % of inhibition (% inhibition. Results Thirty controls and 52 patients were analyzed. The median percentage of platelets exhibiting CD62P expression and PAC-1 binding by FC evaluation after stimulation in the presence of PG E1 was 25.4% (IQR: 21.4–33.1% and 3.5% (1.7–9.4%, respectively. Only 6 patients receiving DAT (11.5% had both values above the 1st quartile of controls, and were defined as LR. Evaluation of the same patients with the VerifyNow-P2Y12 test revealed that the area under the receiver-operating-characteristic (ROC curve was 0.94 (95% CI: 0.84–0.98, p 213 PRU gave the maximum accuracy for the detection of patients defined as having LR by FC. Conclusion In conclusion our findings show that a cut-off value of ≤ 15% inhibition or > 213 PRU in the VerifyNow-P2Y12 test may provide the best accuracy for the identification of patients with LR.

The influence of propofol on P-selectin expression and nitric oxide production in re-oxygenated human umbilical vein endothelial cells.

LENUS (Irish Health Repository)

Corcoran, T B

2012-02-03

BACKGROUND: Reperfusion injury is characterized by free radical production and endothelial inflammation. Neutrophils mediate much of the end-organ injury that occurs, requiring P-selectin-mediated neutrophil-endothelial adhesion, and this is associated with decreased endothelial nitric oxide production. Propofol has antioxidant properties in vitro which might abrogate this inflammation. METHODS: Cultured human umbilical vein endothelial cells were exposed to 20 h of hypoxia and then returned to normoxic conditions. Cells were treated with saline, Diprivan 5 microg\\/l or propofol 5 microg\\/l for 4 h after re-oxygenation and were then examined for P-selectin expression and supernatant nitric oxide concentrations for 24 h. P-selectin was determined by flow cytometry, and culture supernatant nitric oxide was measured as nitrite. RESULTS: In saline-treated cells, a biphasic increase in P-selectin expression was demonstrated at 30 min (P = 0.01) and 4 h (P = 0.023) after re-oxygenation. Propofol and Diprivan prevented these increases in P-selectin expression (P < 0.05). Four hours after re-oxygenation, propofol decreased endothelial nitric oxide production (P = 0.035). CONCLUSION: This is the first study to demonstrate an effect of propofol upon endothelial P-selectin expression. Such an effect may be important in situations of reperfusion injury such as cardiac transplantation and coronary artery bypass surgery. We conclude that propofol attenuates re-oxygenation-induced endothelial inflammation in vitro.

Selected immunological changes in patients with Goeckerman's therapy TNF-alpha, sE-selectin, sP-selectin, sICAM-1 and IL-8

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Borska, L.; Fiala, Z.; Krejsek, J.; Andrys, C.; Vokurkova, D.; Hamakova, K.; Kremlacek, J.; Ettler, K. [Charles University, Hradec Kralove (Czech Republic). Faculty of Medicine

2006-07-01

Psoriasis is one of the most frequent inflammatory skin diseases in which abnormal individual immune reactivity plays an important role. The aim of the present study was to describe selected immunological changes, concerning pro-inflammatory cytokines (TNF-alpha, IL-8) and adhesion molecules (sE-selectin, sP-selectin, sICAM-1), in 56 patients cured by Goeckerman's therapy (GT). GT includes dermal application of crude coal tar (containing polycyclic aromatic hydrocarbons) and exposure to UV radiation.

NF-kB activity-dependent P-selectin involved in ox-LDL-induced foam cell formation in U937 cell

International Nuclear Information System (INIS)

Wang, Yi; Wang, Xiang; Sun, Minghui; Zhang, Zhenyu; Cao, Heng; Chen, Xiaoqing

2011-01-01

Highlights: → Ox-LDL induced foam cell formation in the human U937 promonocytic cell line in a dose- and time-dependent manner. → Ox-LDL induced expression of P-selectin through degradation of IkBa and augment of NF-kB activity and protein level during macrophage-derived foam cell formation. → P-selectin and NF-kB may be identified as pivotal regulators of ox-LDL-induced foam cell formation. → Therapy based on the inhibition of P-selectin and NF-kB may complement conventional treatments to prevent atherosclerosis. -- Abstract: Oxidized low-density lipoprotein (ox-LDL) plays a critical role in regulation of atherosclerosis. However, little is known about the role of Nuclear factor kB (NF-kB) activity-dependent P-selectin in ox-LDL-induced foam cell formation during atherosclerosis. In this study, we first investigated ox-LDL induced foam cell formation in the human U937 promonocytic cell line in a dose- and time-dependent manner. Treatment of U937 cells with ox-LDL increased lipid accumulation as well as intracellular cholesterol content. Next, a comparative analysis of gene expression profiling using cDNA microarray and Real-time-PCR indicated that ox-LDL exposure induced, in three treated groups, an extremely marked increase in the mRNA level of P-selectin. Protein levels of P-selectin and its upstream regulators IkBa and NF-kB showed that NF-kB pathway is involved in the ox-LDL-induced foam cell formation. Finally, overexpression of NF-kB significantly accelerated, whereas, inhibition of NF-kB with siRNA remarkably attenuated ox-LDL-induced macrophage-derived foam cell formation. It was concluded that the activity of NF-kB is augmented during macrophage-derived foam cell formation. Activation of NF-kB increased, whereas, inhibition of NF-kB decreased ox-LDL-induced P-selectin expression and lipid accumulation in macrophages, suggesting ox-LDL induced expression of P-selectin through degradation of IkBa and activation of NF-kB in the regulation of foam

NF-kB activity-dependent P-selectin involved in ox-LDL-induced foam cell formation in U937 cell

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi, E-mail: wangyi2004a@126.com [Department of Cardiology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200080 (China); Wang, Xiang; Sun, Minghui; Zhang, Zhenyu; Cao, Heng; Chen, Xiaoqing [Department of Cardiology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200080 (China)

2011-08-05

Highlights: {yields} Ox-LDL induced foam cell formation in the human U937 promonocytic cell line in a dose- and time-dependent manner. {yields} Ox-LDL induced expression of P-selectin through degradation of IkBa and augment of NF-kB activity and protein level during macrophage-derived foam cell formation. {yields} P-selectin and NF-kB may be identified as pivotal regulators of ox-LDL-induced foam cell formation. {yields} Therapy based on the inhibition of P-selectin and NF-kB may complement conventional treatments to prevent atherosclerosis. -- Abstract: Oxidized low-density lipoprotein (ox-LDL) plays a critical role in regulation of atherosclerosis. However, little is known about the role of Nuclear factor kB (NF-kB) activity-dependent P-selectin in ox-LDL-induced foam cell formation during atherosclerosis. In this study, we first investigated ox-LDL induced foam cell formation in the human U937 promonocytic cell line in a dose- and time-dependent manner. Treatment of U937 cells with ox-LDL increased lipid accumulation as well as intracellular cholesterol content. Next, a comparative analysis of gene expression profiling using cDNA microarray and Real-time-PCR indicated that ox-LDL exposure induced, in three treated groups, an extremely marked increase in the mRNA level of P-selectin. Protein levels of P-selectin and its upstream regulators IkBa and NF-kB showed that NF-kB pathway is involved in the ox-LDL-induced foam cell formation. Finally, overexpression of NF-kB significantly accelerated, whereas, inhibition of NF-kB with siRNA remarkably attenuated ox-LDL-induced macrophage-derived foam cell formation. It was concluded that the activity of NF-kB is augmented during macrophage-derived foam cell formation. Activation of NF-kB increased, whereas, inhibition of NF-kB decreased ox-LDL-induced P-selectin expression and lipid accumulation in macrophages, suggesting ox-LDL induced expression of P-selectin through degradation of IkBa and activation of NF-kB in the

Circulating endothelial cells (CECs and E-selectin: Predictors of preeclampsia

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Ferdous Mehrabian

2012-01-01

Full Text Available Background: Circulating endothelial cells (CECs and E-selectin are known as sensitive and specific markers of en-dothelial dysfunction. This study investigated whether CECs and E-selectin are surrogate biomarkers of preeclampsia and if measurement of CECs and E-selectin, early in the third trimester, could be a means of predicting preeclampsia. Methods: In this prospective, descriptive-analytic study, rollover test was performed on 523 pregnant women during 28-30 weeks of gestation. CECs were measured by anti-CD 146-driven immunomagnetic isolation in women with posi-tive rollover test. They were followed up prospectively until delivery without any active intervention. Women with and without preeclampsia were determined. The number of CECs and level of E-selectin were compared in the two studied groups. Results: From the 47 pregnant women with positive rollover test who were selected and followed up, 22 individuals were diagnosed with preeclampsia while the remainder were normotensive. Mean CEC numbers was significantly high-er in preeclamptic women than normal pregnancies (24.7 cells/mL vs. 13 cells/mL. The best cut-off point for CEC numbers was 6.5 with a sensitivity of 78.9% and a specificity of 69.1%. The level of E-selectin was significantly higher in mothers with preeclampsia (p < 0.05. Conclusions: Higher levels of CECs and E-selectin in women with positive rollover test who developed preeclampsia prior to onset of the complication were predictive of preeclampsia. However, larger studies are needed to confirm these findings.

CLA and CD62E expression in oral lichen planus lesions.

Science.gov (United States)

Werneck, Juliana Tristão; Dias, Eliane Pedra; Gonçalves, Lucio Souza; Silva Junior, Arley

2016-03-01

There are few reports on the migration of CLA+ T cells through E-selectin in cutaneous lichen planus, with only one study on oral lichen planus (OLP). This study aimed to analyze CLA expression and assess whether there is a correlation with E-selectin (CD62E) in OLP lesions. Biopsies were performed on 11 patients including two areas: one without clinical and histopathological features of OLP [perilesional group (PLG)] and the other with clinical and histopathological features of OLP [OLP group (OLPG)]. The specimens obtained were divided into two: One was fixed in formalin for routine analysis (H&E), and the other was frozen for CD3, CD4, CD8, CLA, and CD62E immunofluorescence markers. More CD4+ (median 1409, range 860-2519), CD8+ (median 1568, range 654-3258), and CLA+ T cells (median 958, range 453-2198) and higher CD62E expression (median 37, range 27-85) were identified in OLPG (P = 0.003; P = 0.003; P = 0.004; P = 0.003, respectively) than those in PLG. The median prevalence analysis was also significantly higher for CLA+CD8+ T cells in OLPG (OLPG = 39.4%, range 18.4-64.2; PLG = 29.4%, range 12.1-47.1) (P = 0.026). None of the correlations between CD3+ or CLA+ T cells and CD62E in OLPG and in PLG were significant. The significant presence of CLA+ T cells and E-selectin expressions in the OLPG suggests their involvement in the etiopathogenesis of OLP; however, only a weak correlation between CLA+ T cells and E-selectin was observed. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of Platelets on Platelet Concentrate Product on the Activation of Human Peripheral Blood Monocyte Cells

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N Sadat Razavi Hoseini

2016-02-01

Full Text Available Introduction: Monocytes can interact with platelets due to their surface molecules such as P-selectin glycoprotein ligand-1 (PSGL-1, and form monocyte-platelet complex. In the present study, the effects of platelets interaction of platelet concentrates (PCs and peripheral blood monocytes were investigated in vitro as a model to predict the probable interactions of these cells and consequently activation of monocytes. Methods: In this experimental study, units of whole blood and PCs were prepared from Tehran Blood Transfusion Center. After isolation of monocytes from the whole blood, these cells were treated with PC- derived platelets. The activation of monocytes was assessed before and after treatment by the analysis of the respiratory burst of monocytes using dihydrorhodamine 123 (DHR-123. The study data were analyzed using the non-parametric test of Wilcoxon. Results: The purity of monocytes was determined as 86.1±2 using NycoPrep method. The respiratory burst of monocytes was increased after exposure with platelets. In fact, the difference was significant when platelets were used on the 5th day of storage (P=0.001. Conclusions: The study findings revealed that platelets have an efficient capacity to stimulate and activate monocytes. The possible involvement of molecules in the interaction of platelet-monocyte demand to be further studied in future.

In-silico analysis of amotosalen hydrochloride binding to CD-61 of platelets

International Nuclear Information System (INIS)

Chaudhary, H.T.

2016-01-01

To determine the docking of Amotosalen hydrochloride (AH) at CD-61 of platelets, and to suggest the cause of bleeding in AH treated platelets transfusion. Study Design: Descriptive study. Place and Duration of Study: Medical College, Taif University, Taif, Saudi Arabia, from October 2014 to May 2015. Methodology: The study was carried out in-silico. PDB (protein data bank) code of Tirofiban bound to CD-61 was 2vdm. CD-61 was docked with Tirofiban using online docking tools, i.e. Patchdock and Firedock. Then, Amotosalen hydrochloride and CD-61 were also docked. Best docking poses to active sites of 2vdm were found. Ligplot of interactions of ligands and CD-61 were obtained. Then comparison of hydrogen bonds, hydrogen bond lengths, and hydrophobic bonds of 2vdm molecule and best poses of docking results were done. Patchdock and Firedock results of best poses were also analysed using SPSS version 16. Results: More amino acids were involved in hydrogen and hydrophobic bonds in Patchdock and Firedock docking of Amotosalen hydrochloride with CD-61 than Patchdock and Firedock docking of CD-61 with Tirofiban. The binding energy was more in latter than former. Conclusion: Amotosalen hydrochloride binds to the active site of CD-61 with weaker binding force. Haemorrhage seen in Amotosalen hydrochloride-treated platelets might be due to binding of Amotosalen hydrochloride to CD-61. (author)

Long-term impact of radiation on plasma concentrations of cytokines (IL-1 and IL-6) and adhesion molecules (ICAM-1 and P-selectin) in Chernobyl clean-up workers from Latvia

International Nuclear Information System (INIS)

Kurjane, N.; Kirsfinks, M.; Hagina, E.; Socnevs, A.

2001-01-01

Study was undertaken to evaluate plasma concentrations of interleukin-1beta (IL-1), interleukin-6 (IL-6), and adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and P-selectin in persons who participated in the clean-up work of the Chernobyl NPP explosion aftereffects. 40 Chernobyl clean-up workers suffering from most common neurological diseases - polyneuropathy and encephalopathy, and 40 healthy blood donors were analyzed for plasma levels of IL-6, IL1-β, sICAM-1 and sP-selectin 13 years after the accident. The documented external radiation dosage to the investigated Chernobyl clean-up workers was exposed from 0,009 to 0,28 Gy. Significantly elevated plasma concentrations of IL-6 and P-selectin but not of IL-1β were found in Chernobyl clean-up labourers as compared to those in healthy blood donors. (p<0.01). There was no obvious association of cytokine and adhesion molecule levels with radiation doses, as individuals working in the Chernobyl area in 1986 at a time when the external radiation exposure was higher revealed similar plasma concentrations if compared to those of a later period of time (1987-1990). (authors)

Red Wine Inhibits Aggregation and Increases ATP-diphosphohydrolase (CD39) Activity of Rat Platelets in Vitro.

Science.gov (United States)

Caiazzo, Elisabetta; Tedesco, Idolo; Spagnuolo, Carmela; Russo, Gian Luigi; Ialenti, Armando; Cicala, Carla

2016-06-01

Moderate consumption of red wine has been shown to exert a peculiar cardioprotective effect compared with other alcoholic beverages; inhibition of platelet aggregation seems to be one of the mechanisms underlying this beneficial effect. CD39/ATP-diphosphohydrolase is an integral membrane glycoprotein metabolizing ATP and ADP to AMP; in concert with CD73/ecto-5'-nucleotidase, it contributes to extracellular adenosine accumulation. CD39 is considered a key modulator of thrombus formation; it inhibits platelet aggregation by promoting ADP hydrolysis. There is evidence that red wine consumption increases CD39 activity in platelets from streptozotocin-induced diabetic rats. Here we show that two kinds of Aglianico red wines inhibit aggregation and increase ATP--and ADPase activity in rat platelets.

Nano- to microscale dynamics of P-selectin detachment from leukocyte interfaces. II. Tether flow terminated by P-selectin dissociation from PSGL-1.

Science.gov (United States)

Heinrich, Volkmar; Leung, Andrew; Evans, Evan

2005-03-01

We have used a biomembrane force probe decorated with P-selectin to form point attachments with PSGL-1 receptors on a human neutrophil (PMN) in a calcium-containing medium and then to quantify the forces experienced by the attachment during retraction of the PMN at fixed speed. From first touch to final detachment, the typical force history exhibited the following sequence of events: i), an initial linear-elastic displacement of the PMN surface, ii), an abrupt crossover to viscoplastic flow that signaled membrane separation from the interior cytoskeleton and the beginning of a membrane tether, and iii), the final detachment from the probe tip most often by one precipitous step of P-selectin:PSGL-1 dissociation. Analyzing the initial elastic response and membrane unbinding from the cytoskeleton in our companion article I, we focus in this article on the regime of tether extrusion that nearly always occurred before release of the extracellular adhesion bond at pulling speeds > or =1 microm/s. The force during tether growth appeared to approach a plateau at long times. Examined over a large range of pulling speeds up to 150 microm/s, the plateau force exhibited a significant shear thinning as indicated by a weak power-law dependence on pulling speed, f(infinity) = 60 pN(nu(pull)/microm/s)(0.25). Using this shear-thinning response to describe the viscous element in a nonlinear Maxwell-like fluid model, we show that a weak serial-elastic component with a stiffness of approximately 0.07 pN/nm provides good agreement with the time course of the tether force approach to the plateau under constant pulling speed.

D-lactic acid interferes with the effects of platelet activating factor on bovine neutrophils.

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Alarcón, P; Conejeros, I; Carretta, M D; Concha, C; Jara, E; Tadich, N; Hidalgo, M A; Burgos, R A

2011-11-15

D-lactic acidosis occurs in ruminants, such as cattle, with acute ruminal acidosis caused by ingestion of excessive amounts of highly fermentable carbohydrates. Affected animals show clinical signs similar to those of septic shock, as well as acute laminitis and liver abscesses. It has been proposed that the inflammatory response and susceptibility to infection could both be caused by the inhibition of phagocytic mechanisms. To determine the effects of d-lactic acid on bovine neutrophil functions, we pretreated cells with different concentrations of D-lactic acid and measured intracellular pH using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and calcium flux using FLUO-3 AM-loaded neutrophils. Reactive oxygen species (ROS) production was measured using a luminol chemiluminescence assay, and MMP-9/gelatinase-B granule release was measured by zymography. CD11b and CD62L/l-selectin expression, changes in cell shape, superoxide anion production, phagocytosis of Escherichia coli-Texas red bioparticles, and apoptosis were all measured using flow cytometry. Our results demonstrated that D-lactic acid reduced ROS production, CD11b upregulation and MMP-9 release in bovine neutrophils treated with 100 nM platelet-activating factor (PAF). D-lactic acid induced MMP-9 release and, at higher concentrations, upregulated CD11b expression, decrease L-selectin expression, and induces late apoptosis. We concluded that D-lactic acid can interfere with neutrophil functions induced by PAF, leading to reduced innate immune responses during bacterial infections. Moreover, the increase of MMP-9 release and CD11b expression induced by 10mM D-lactic acid could promote an nonspecific neutrophil-dependent inflammatory reaction in cattle with acute ruminal acidosis. Copyright © 2011 Elsevier B.V. All rights reserved.

Modification of P-selectin glycoprotein ligand-1 with a natural killer cell-restricted sulfated lactosamine creates an alternate ligand for L-selectin

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André, Pascale; Spertini, Olivier; Guia, Sophie; Rihet, Pascal; Dignat-George, Françoise; Brailly, Hervé; Sampol, José; Anderson, Paul J.; Vivier, Eric

2000-01-01

Natural killer (NK) cells are components of the innate immune system that can recognize and kill virally infected cells, tumor cells, and allogeneic cells without prior sensitization. NK cells also elaborate cytokines (e.g., interferon-γ and tumor necrosis factor-α) and chemokines (e.g., macrophage inflammatory protein-1α) that promote the acquisition of antigen-specific immunity. NK cell differentiation is accompanied by the cell surface expression of a mucin-like glycoprotein bearing an NK cell-restricted keratan sulfate-related lactosamine carbohydrate, the PEN5 epitope. Here, we report that PEN5 is a post-translational modification of P-selectin glycoprotein ligand-1 (PSGL-1). The PEN5 epitope creates on PSGL-1 a unique binding site for L-selectin, which is independent of PSGL-1 tyrosine sulfation. On the surface of NK cells, the expression of PEN5 is coordinated with the disappearance of L-selectin and the up-regulation of Killer cell Ig-like Receptors (KIR). These results indicate that NK cell differentiation is accompanied by the acquisition of a unique carbohydrate, PEN5, that can serve as part of a combination code to deliver KIR+ NK cells to specific tissues. PMID:10725346

Efficacy of Clopidogrel and Clinical Outcome When Clopidogrel Is Coadministered With Atorvastatin and Lansoprazole: A Prospective, Randomized, Controlled Trial.

Science.gov (United States)

Zhang, Jian-rong; Wang, Di-qing; Du, Jun; Qu, Guang-su; Du, Jian-lin; Deng, Song-bai; Liu, Ya-jie; Cai, Jin-xi; She, Qiang

2015-12-01

This prospective, randomized, nonblind, controlled trial evaluated the effects of clopidogrel on platelet function upon coadministration with atorvastatin and lansoprazole. One hundred four adult patients with non-ST-segment elevated acute coronary syndrome (NSTE-ACS) who underwent percutaneous coronary intervention (PCI) with drug-eluting stent implantation were included. All patients were treated with standard dual antiplatelet therapy (DAPT) plus rosuvastatin 10  mg daily after the operation. On the sixth day after PCI, patients were randomly divided into 4 groups, Group A: DAPT + atorvastatin 20  mg daily (a change from rosuvastatin to atorvastatin) + lansoprazole 30  mg daily, Group B: DAPT + atorvastatin 20  mg daily (a change from rosuvastatin to atorvastatin), Group C: DAPT + lansoprazole 30  mg daily (continuing to take rosuvastatin), Group D is the control group. Additional drugs were used according to the situation of patients. Platelet function and concentrations of platelet activation markers (granular membrane protein 140 (P-selectin), thromboxane B2 (TXB2), and human soluble cluster of differentiation 40 ligand (sCD40L)) were assessed before randomization and at 15- and 30-day follow-up visits. All patients were maintained on treatment for 6 months and observed for bleeding and ischemic events. A total of 104 patients were enrolled, 27 patients in group A, 26 patients in Group B/C, 25 patients in Group D separately, and all the patients were analyzed. There were no differences in platelet function and the levels of platelet activation markers (P-selectin, TXB2, and sCD40L) among or within the 4 groups at the 3 time points of interest (P > 0.05). In the subsequent 6 months, no significant bleeding events occurred, and 12 patients experienced ischemic events, these results were also not significantly different among the groups (P > 0.05). In patients diagnosed with NSTE-ACS who have had drug-eluting stent implantation

Extracellular histones promote thrombin generation through platelet-dependent mechanisms: involvement of platelet TLR2 and TLR4

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Semeraro, Fabrizio; Ammollo, Concetta T.; Morrissey, James H.; Dale, George L.; Friese, Paul; Esmon, Naomi L.

2011-01-01

The release of histones from dying cells is associated with microvascular thrombosis and, because histones activate platelets, this could represent a possible pathogenic mechanism. In the present study, we assessed the influence of histones on the procoagulant potential of human platelets in platelet-rich plasma (PRP) and in purified systems. Histones dose-dependently enhanced thrombin generation in PRP in the absence of any trigger, as evaluated by calibrated automated thrombinography regardless of whether the contact phase was inhibited. Activation of coagulation required the presence of fully activatable platelets and was not ascribable to platelet tissue factor, whereas targeting polyphosphate with phosphatase reduced thrombin generation even when factor XII (FXII) was blocked or absent. In the presence of histones, purified polyphosphate was able to induce thrombin generation in plasma independently of FXII. In purified systems, histones induced platelet aggregation; P-selectin, phosphatidylserine, and FV/Va expression; and prothrombinase activity. Blocking platelet TLR2 and TLR4 with mAbs reduced the percentage of activated platelets and lowered the amount of thrombin generated in PRP. These data show that histone-activated platelets possess a procoagulant phenotype that drives plasma thrombin generation and suggest that TLR2 and TLR4 mediate the activation process. PMID:21673343

Supplementation with mixed tocopherols increases serum and blood cell gamma-tocopherol but does not alter biomarkers of platelet activation in subjects with type 2 diabetes.

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Clarke, Michael W; Ward, Natalie C; Wu, Jason H Y; Hodgson, Jonathan M; Puddey, Ian B; Croft, Kevin D

2006-01-01

Some studies have shown potential benefit of vitamin E on platelet function, but several clinical trials failed to show improved cardiovascular outcome with alpha-tocopherol supplementation. Gamma-tocopherol, a major dietary form of vitamin E, may have protective properties different from those of alpha-tocopherol. We compared the effects of supplementation with alpha-tocopherol (500 mg) and a gamma-tocopherol-rich compound (500 mg, containing 60% gamma-tocopherol) on serum and cellular tocopherol concentrations, urinary tocopherol metabolite excretion, and in vivo platelet activation in subjects with type 2 diabetes. Fifty-eight subjects were randomly assigned to receive either 500 mg alpha-tocopherol/d, 500 mg mixed tocopherols/d, or matching placebo. Serum, erythrocyte, and platelet tocopherol and urinary metabolite concentrations were measured at baseline and after the 6-wk intervention. Soluble CD40 ligand, urinary 11-dehydro-thromboxane B2, serum thromboxane B2, soluble P-selectin, and von Willebrand factor were measured as biomarkers of in vivo platelet activation. Serum alpha-tocopherol increased with both tocopherol treatments. Serum and cellular gamma-tocopherol increased 4-fold (P tocopherol group, whereas red blood cell gamma-tocopherol decreased significantly after alpha-tocopherol supplementation. Excretion of alpha-carboxyethyl-hydroxychroman increased significantly after supplementation with alpha-tocopherol and mixed tocopherols. Excretion of gamma-carboxyethyl-hydroxychroman increased significantly after supplementation with mixed tocopherols and after that with alpha-tocopherol, which may reflect the displacement of gamma-tocopherol by alpha-tocopherol due to incorporation of the latter into lipoproteins in the liver. Neither treatment had any significant effect on markers of platelet activation. Supplementation with alpha-tocopherol decreased red blood cell gamma-tocopherol, whereas mixed tocopherols increased both serum alpha-tocopherol and

A prospective randomized trial of aspirin-clopidogrel combination therapy and dose-adjusted warfarin on indices of thrombogenesis and platelet activation in atrial fibrillation.

Science.gov (United States)

Kamath, Sridhar; Blann, Andrew D; Chin, Bernard S P; Lip, Gregory Y H

2002-08-07

This study was designed to investigate whether or not combination aspirin-clopidogrel therapy would reduce markers of thrombogenesis and platelet activation in atrial fibrillation (AF), in a manner similar to warfarin. Dose-adjusted warfarin is beneficial as thromboprophylaxis in AF, but potentially serious side effects and regular monitoring leave room for alternative therapies. METHODS; We randomized 70 patients with nonvalvular AF who were not on any antithrombotic therapy to either dose-adjusted warfarin (international normalized ratio 2 to 3) (Group I) or combination therapy with aspirin 75 mg and clopidogrel 75 mg (Group II). Plasma indices of thrombogenesis (fibrin D-dimer, prothrombin fragment 1+2) and platelet activation (beta-thromboglobulin [TG] and soluble P-selectin) were quantified, along with platelet aggregation responses to standard agonists, at baseline (pretreatment) and at six weeks posttreatment. RESULTS; Pretreatment levels of fibrin D-dimer (p = 0.001), beta-TG (p = 0.01) and soluble P-selectin (p = 0.03) were raised in patients with AF, whereas plasma prothrombin fragment 1+2 levels and platelet aggregation were not significantly different compared with controls. Dose-adjusted warfarin reduced plasma levels of fibrin D-dimer, prothrombin fragment 1+2 and beta-thromboglobulin levels at six weeks (all p failed to reduce plasma indices of thrombogenesis and platelet activation in AF, although some aspects of ex vivo platelet aggregation were altered. Anticoagulation with warfarin may be superior to combination aspirin-clopidogrel therapy as thromboprophylaxis in AF.

Combined blockade of ADP receptors and PI3-kinase p110β fully prevents platelet and leukocyte activation during hypothermic extracorporeal circulation.

Directory of Open Access Journals (Sweden)

Stefanie Krajewski

Full Text Available Extracorporeal circulation (ECC and hypothermia are used to maintain stable circulatory parameters and improve the ischemia tolerance of patients in cardiac surgery. However, ECC and hypothermia induce activation mechanisms in platelets and leukocytes, which are mediated by the platelet agonist ADP and the phosphoinositide-3-kinase (PI3K p110β. Under clinical conditions these processes are associated with life-threatening complications including thromboembolism and inflammation. This study analyzes effects of ADP receptor P(2Y(12 and P(2Y(1 blockade and PI3K p110β inhibition on platelets and granulocytes during hypothermic ECC. Human blood was treated with the P(2Y(12 antagonist 2-MeSAMP, the P(2Y(1 antagonist MRS2179, the PI3K p110β inhibitor TGX-221, combinations thereof, or PBS and propylene glycol (controls. Under static in vitro conditions a concentration-dependent effect regarding the inhibition of ADP-induced platelet activation was found using 2-MeSAMP or TGX-221. Further inhibition of ADP-mediated effects was achieved with MRS2179. Next, blood was circulated in an ex vivo ECC model at 28°C for 30 minutes and various platelet and granulocyte markers were investigated using flow cytometry, ELISA and platelet count analysis. GPIIb/IIIa activation induced by hypothermic ECC was inhibited using TGX-221 alone or in combination with P(2Y blockers (p<0.05, while no effect of hypothermic ECC or antiplatelet agents on GPIIb/IIIa and GPIbα expression and von Willebrand factor binding was observed. Sole P(2Y and PI3K blockade or a combination thereof inhibited P-selectin expression on platelets and platelet-derived microparticles during hypothermic ECC (p<0.05. P(2Y blockade alone or combined with TGX-221 prevented ECC-induced platelet-granulocyte aggregate formation (p<0.05. Platelet adhesion to the ECC surface, platelet loss and Mac-1 expression on granulocytes were inhibited by combined P(2Y and PI3K blockade (p<0.05. Combined blockade of P

The use of the soluble adhesion molecules sE-selectin, sICAM-1, sVCAM-1, sPECAM-1 and their ligands CD11a and CD49d as diagnostic and prognostic biomarkers in septic and critically ill non-septic ICU patients

DEFF Research Database (Denmark)

Kjaergaard, Anders G; Dige, Anders; Nielsen, Jeppe S.

2016-01-01

Endothelial activation is pivotal in the development and escalation of sepsis. Central to endothelial activation is the endothelial up-regulation of cellular adhesion molecules (CAMs) including E-selectin, ICAM-1, VCAM-1, and PECAM-1. Shed CAMs are also found in circulating soluble forms (s...... critically ill non-septic patients were included. All patients had an APACHE II score above 13 at ICU admission. Fifteen healthy volunteers served as controls. Flow cytometry was used to estimate levels of sE-selectin, sICAM-1, sVCAM-1, sPECAM-1, and the cellular expression of CD11a and CD49d. Levels of s...

[Effects of lysine clonixinate on platelet function. Comparison with other non-steroidal anti-inflammatory agents].

Science.gov (United States)

Kramer, E H; Sassetti, B; Kaminker, A J; De Los Santos, A R; Martí, M L; Di Girolamo, G

2001-01-01

One of the mechanisms of action of non steroid antiinflammatory drugs (NSAIDs) consists of inhibition of prostaglandin synthesis. This explains many of the pharmacological effects and adverse events observed in medical practice. Administration of NSAIDs to patients with hemostatic disorders or perioperative conditions entails the risk of bleeding due to inhibition of platelet function. This study deals with platelet changes induced by lysine clonixinate vs diclofenac, ibuprofen and aspirin in classical tests such as platelet count, platelet factor 3 (PF3) activity and platelet aggregation with various inductors and more recent procedures such as P-selectin measurement by flow cytometry. Unlike control drugs, lysine clonixinate did not induce changes in platelet count or function when administered to healthy volunteers at the commonly used therapeutic doses.

Platelet activation and platelet-leukocyte interaction in β-thalassemia/hemoglobin E patients with marked nucleated erythrocytosis.

Science.gov (United States)

Keawvichit, Rassamon; Khowawisetsut, Ladawan; Chaichompoo, Porntip; Polsrila, Korakot; Sukklad, Suchana; Sukapirom, Kasama; Khuhapinant, Archrob; Fucharoen, Suthat; Pattanapanyasat, Kovit

2012-11-01

Patients with thalassemia, an inherited hemolytic anemia, have increased risk of hypercoagulable complications. A whole blood flow cytometric (FCM) method has been used for studies of platelet activation and platelet-leukocyte aggregation in these patients. However, this FCM method presents technical difficulties because of the high proportion of immature red blood cells (RBCs) in these patients. A protocol for the simultaneous measurement of platelet activation and their aggregation with leukocyte populations in whole blood using four-color FCM which excluded immature RBC was devised, and evaluated for the evaluation of platelet function in patients with β-thalassemia/hemoglobin E (HbE). Whole blood from these patients and from healthy volunteers was stained for platelet activation and platelet-leukocyte aggregates using anti-CD42a, anti-CD62P, anti-CD45 and glycophorin A (GPA) conjugated with different fluorochromes. Our FCM method is simple, effective and based on the assumption that GPA is present on all immature RBCs, but is not expressed on CD45⁺ leukocytes. Results from the studies showed that blood samples from these patients contained a high frequency of circulating activated platelets (CD42a⁺/CD62P⁺) when compared to samples from healthy individuals. The percentage of platelet-neutrophil, platelet-monocyte-but not platelet-lymphocyte-aggregates were also elevated in both thalassemia genotypes with marked increase in patients who had undergone splenectomy. These findings suggest that platelets adhere to neutrophils and monocytes are activated which support the clinical observation that splenectomized thalassemia patients have an increased risk of arterial or venous thrombotic manifestations.

Modification of Pulsed Electric Field Conditions Results in Distinct Activation Profiles of Platelet-Rich Plasma.

Science.gov (United States)

Frelinger, Andrew L; Gerrits, Anja J; Garner, Allen L; Torres, Andrew S; Caiafa, Antonio; Morton, Christine A; Berny-Lang, Michelle A; Carmichael, Sabrina L; Neculaes, V Bogdan; Michelson, Alan D

2016-01-01

Activated autologous platelet-rich plasma (PRP) used in therapeutic wound healing applications is poorly characterized and standardized. Using pulsed electric fields (PEF) to activate platelets may reduce variability and eliminate complications associated with the use of bovine thrombin. We previously reported that exposing PRP to sub-microsecond duration, high electric field (SMHEF) pulses generates a greater number of platelet-derived microparticles, increased expression of prothrombotic platelet surfaces, and differential release of growth factors compared to thrombin. Moreover, the platelet releasate produced by SMHEF pulses induced greater cell proliferation than plasma. To determine whether sub-microsecond duration, low electric field (SMLEF) bipolar pulses results in differential activation of PRP compared to SMHEF, with respect to profiles of activation markers, growth factor release, and cell proliferation capacity. PRP activation by SMLEF bipolar pulses was compared to SMHEF pulses and bovine thrombin. PRP was prepared using the Harvest SmartPreP2 System from acid citrate dextrose anticoagulated healthy donor blood. PEF activation by either SMHEF or SMLEF pulses was performed using a standard electroporation cuvette preloaded with CaCl2 and a prototype instrument designed to take into account the electrical properties of PRP. Flow cytometry was used to assess platelet surface P-selectin expression, and annexin V binding. Platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), endothelial growth factor (EGF) and platelet factor 4 (PF4), and were measured by ELISA. The ability of supernatants to stimulate proliferation of human epithelial cells in culture was also evaluated. Controls included vehicle-treated, unactivated PRP and PRP with 10 mM CaCl2 activated with 1 U/mL bovine thrombin. PRP activated with SMLEF bipolar pulses or thrombin had similar light scatter profiles, consistent with the presence of platelet

Modification of Pulsed Electric Field Conditions Results in Distinct Activation Profiles of Platelet-Rich Plasma.

Directory of Open Access Journals (Sweden)

Andrew L Frelinger

Full Text Available Activated autologous platelet-rich plasma (PRP used in therapeutic wound healing applications is poorly characterized and standardized. Using pulsed electric fields (PEF to activate platelets may reduce variability and eliminate complications associated with the use of bovine thrombin. We previously reported that exposing PRP to sub-microsecond duration, high electric field (SMHEF pulses generates a greater number of platelet-derived microparticles, increased expression of prothrombotic platelet surfaces, and differential release of growth factors compared to thrombin. Moreover, the platelet releasate produced by SMHEF pulses induced greater cell proliferation than plasma.To determine whether sub-microsecond duration, low electric field (SMLEF bipolar pulses results in differential activation of PRP compared to SMHEF, with respect to profiles of activation markers, growth factor release, and cell proliferation capacity.PRP activation by SMLEF bipolar pulses was compared to SMHEF pulses and bovine thrombin. PRP was prepared using the Harvest SmartPreP2 System from acid citrate dextrose anticoagulated healthy donor blood. PEF activation by either SMHEF or SMLEF pulses was performed using a standard electroporation cuvette preloaded with CaCl2 and a prototype instrument designed to take into account the electrical properties of PRP. Flow cytometry was used to assess platelet surface P-selectin expression, and annexin V binding. Platelet-derived growth factor (PDGF, vascular endothelial growth factor (VEGF, endothelial growth factor (EGF and platelet factor 4 (PF4, and were measured by ELISA. The ability of supernatants to stimulate proliferation of human epithelial cells in culture was also evaluated. Controls included vehicle-treated, unactivated PRP and PRP with 10 mM CaCl2 activated with 1 U/mL bovine thrombin.PRP activated with SMLEF bipolar pulses or thrombin had similar light scatter profiles, consistent with the presence of platelet

Novel association of soluble intercellular adhesion molecule 1 and soluble P-selectin with the ABO blood group in a Chinese population.

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Zhang, Wenjing; Xu, Qun; Zhuang, Yunlong; Chen, Yuanfeng

2016-08-01

Recent studies have reported that the ABO gene can affect circulating expression levels of soluble intercellular adhesion molecule 1 (sICAM-1) and soluble P-selectin (sP-selectin) in Caucasians. However, several factors may affect the association, including the distribution and variations of the ABO gene, ethnic diversity and the inflammatory response status. The aim of the present study was to investigate this issue in Asian subjects of various blood groups. A total of 800 blood samples were randomly selected from healthy blood donors. The ABO blood groups were examined using standard serological tests, and ABO genotypes of group A and group AB specimens were analyzed. Plasma concentrations of sICAM-1 and sP-selectin were detected by standard enzyme-linked immunosorbent assays. In healthy Chinese individuals, blood group A was detected to be significantly associated with lower circulating expression levels of sICAM-1 and sP-selectin, compared with group O. Individuals with ≥1 A1 allele had significantly lower expression levels of sICAM-1 and sP-selectin compared with all other ABO groups. The data indicate the significant association of ABO blood group antigens with sICAM-1 and sP-selectin expression levels in a healthy Chinese population, independent of the specific variations and distributions of ABO blood groups among ethnic populations. This result provides evidence for the previously unidentified role of ABO blood group antigens in the regulation of the inflammatory adhesion process. Accordingly, it can be proposed that ABO blood groups may require consideration when soluble adhesion molecules are identified as predictors for cardiovascular disease.

Mice with deleted multimerin 1 and alpha-synuclein genes have impaired platelet adhesion and impaired thrombus formation that is corrected by multimerin 1.

Science.gov (United States)

Reheman, Adili; Tasneem, Subia; Ni, Heyu; Hayward, Catherine P M

2010-05-01

Multimerin 1 is a stored platelet and endothelial cell adhesive protein that shows significant conservation. In vitro, multimerin 1 supports platelet adhesion and it also binds to collagen and enhances von Willebrand factor-dependent platelet adhesion to collagen. As selective, multimerin 1 deficient mice have not been generated, we investigated multimerin 1 effects on platelet adhesion using a subpopulation of C57BL/6J mice with tandem deletion of the genes for multimerin 1 and alpha-synuclein, a protein that inhibits alpha-granule release in vitro. We postulated that multimerin 1/alpha-synuclein deficient mice might show impaired platelet adhesive function from multimerin 1 deficiency and increased alpha-granule release from alpha-synuclein deficiency. Platelet function was assessed by intravital microscopy, after ferric chloride injury, using untreated and human multimerin 1-transfused multimerin 1/alpha-synuclein deficient mice, and by in vitro assays of adhesion, aggregation and thrombin-induced P-selectin release. Multimerin 1/alpha-synuclein deficient mice showed impaired platelet adhesion and their defective thrombus formation at sites of vessel injury improved with multimerin 1 transfusion. Although multimerin 1/alpha-synuclein deficient platelets showed increased P-selectin release at low thrombin concentrations, they also showed impaired adhesion to collagen, and attenuated aggregation with thrombin, that improved with added multimerin 1. Our data suggest that multimerin 1 supports platelet adhesive functions and thrombus formation, which will be important to verify by generating and testing selective multimerin 1 deficient mice. Copyright (c) 2010. Published by Elsevier Ltd.

Role of Soluble P-Selectin Among Type 2 Diabetic Patients with and ...

African Journals Online (AJOL)

Egyptian Journal of Biochemistry and Molecular Biology ... The levels of glucose, HbA1c, total cholesterol, triacylglycerol, LDL-c, hsCRP and sP-selectin level were significantly higher in the diabetic group with coronary artery disease than in the control group and the diabetic group without coronary artery disease. The level ...

Platelet hyperactivity, neurobehavioral symptoms and depression among Indian women chronically exposed to low level of arsenic.

Science.gov (United States)

Mukherjee, Bidisha; Bindhani, Banani; Saha, Hirak; Sinha, Dona; Ray, Manas Ranjan

2014-12-01

The prevalence of neurobehavioral symptoms (NBS) and depression has been investigated in premenopausal rural women of West Bengal, India enrolled from arsenic (As) endemic (groundwater As 11-50 μg/L; n = 342) and control areas (As level ≤ 10 μg/L; n = 312). The subjective symptoms questionnaire and Beck's 21-point depression inventory-II were used for the detection of NBS and depression, respectively. Platelet P-selectin expression was measured by flow cytometry, plasma neurotransmitter activity with high performance liquid chromatography and groundwater As level by atomic absorption spectroscopy. The As level in groundwater was 2.72 ± 1.18 μg/L in control and 28.3 ± 13.51 μg/L in endemic areas (p Women residing in endemic areas demonstrated a higher prevalence of depressive symptoms (39.8 vs. 19.9%, p women had 1.6-times more plasma epinephrine and norepinephrine (p 0.05) from that of controls. Moreover, women from endemic areas had 2.3-times more P-selectin-expressing platelets in their circulation (p Indian women in their child-bearing age. Copyright © 2014 Elsevier Inc. All rights reserved.

Early impact of prescription Omega-3 fatty acids on platelet biomarkers in patients with coronary artery disease and hypertriglyceridemia

DEFF Research Database (Denmark)

Serebruany, Victor L; Miller, Michael; Pokov, Alex N

2011-01-01

Background: Prescription omega-3-acid ethyl esters (PO-3A) have been tested for outcome benefits in patients with coronary artery disease (CAD), arrhythmias and heart failure. Some evidence suggests that PO-3A may exert their benefit via inhibiting platelets. We tested the hypothesis that PO-3A may...... randomized 1:1:1 to Omacor™ 1 g/day (DHA/EPA ratio 1.25:1.0), Omacor 2 g/day, or a placebo for 2 weeks. Platelet tests including aggregometry and flow cytometry and cartridge analyzer readings were performed at baseline and at 1 and 2 weeks following PO-3A therapy. Results: ADP-induced platelet aggregation...... (p = 0.037), GP IIb/IIIa antigen (p = 0.031) and activity (p = 0.024), and P-selectin (p = 0.041) were significantly reduced after PO-3A, while platelet/endothelial cell adhesion molecule (p = 0.09), vitronectin receptor (p = 0.16), formation of platelet-monocyte microparticles (p = 0...

Effect of aliskiren and valsartan combination versus aliskiren monotherapy on hemostatic biomarkers in hypertensive diabetics: Aliskiren and Valsartan Impact in Diabetics pilot trial.

Science.gov (United States)

Serebruany, Victor L; Pokov, Alex N; Aradi, Daniel; Can, Mehmet; DiNicolantonio, James; Kipshidze, Nodar; Atar, Dan

2014-01-01

Valsartan is known to inhibit platelet activity in both in vitro and ex vivo clinical setting, whereas aliskiren in vitro modulates antithrombin-III in plasma. The authors tested how aliskiren and valsartan combination versus aliskiren monotherapy will affect hemostatic biomarkers in mild-to-moderate hypertensive diabetics in the frame of the Aliskiren and Valsartan Impact in Diabetics (AVID) trial. A total of 52 patients with type 2 diabetes and mild-to-moderate hypertension were equally randomized to aliskiren (150-300 mg/d) and valsartan (160 mg/d) versus aliskiren (150-300 mg/d) alone for 4 weeks. A total of 25 biomarkers were serially measured, of which 16 are related to platelet function, 6 to coagulation, and 3 to fibrinolysis. Aliskiren monotherapy has no significant impact on any of the assessed biomarkers. In contrast, valsartan on top of aliskiren provided significant inhibition of ADP-induced platelet aggregation (P=0.032), decreased shear-induced activation measured with PFA-100 analyzer (P=0.041), and diminished expression of GP IIb/IIIa activity (P=0.027) measured by PAC-1 antibody, GP Ib (CD42b, P=0.033), vitronectin receptor (CD51/61, P=0.046), P-selectin (CD62p, P=0.026), lysosome-associated membrane protein (CD107a, P=0.042), and CD40-ligand (CD154, P=0.048). In AVID trial, valsartan in combination with aliskiren mildly but significantly inhibited platelets, confirming previous observations. In contrast, aliskiren monotherapy does not enhance antithrombin activity, suggesting that previous data probably represent a laboratory artifact. Importantly, these randomized data were generated on top of low-dose daily aspirin, supporting extra benefit for combination use of angiotensin receptor blockers and renin inhibitors in high-risk diabetic population.

Characterization of Selectin Ligands on Hematopoietic Stem Cells

KAUST Repository

Mahmood, Hanan

2013-05-18

Successful bone marrow (BM) transplantation requires the homing of the transplanted hematopoietic stem/progenitor cells (HSPCs) to their bone marrow niche, where they undergo differentiation to form mature cells that are eventually released into the peripheral blood. However, the survival rate of patients receiving BM transplants is poor since many of the transplanted HSPCs do not make it to their BM niches in the recipient’s body. Since the availability of HSPCs from traditional sources is limited, transplanting more number of HSPCs is not a solution to this problem. This study aims to characterize the adhesion molecules mediating cell migration in order to better understand the adhesion mechanisms of HSCs with the bone marrow endothelium. This will aid in developing future tools to improve the clinical transplantation of HSPCs. This study also aims to understand the factors that influence HSPC proliferation in the bone marrow niche. E-selectin plays an important role in the process of homing; however, its ligands on HSPCs are not well characterized. We used western blotting and immunoprecipitation to show that endomucin is expressed on HSPCs and plays a role in the binding of HSPCs to E-selectin. We also studied the effect of recombinant E-selectin on the expression of a newly characterized E-selectin ligand in our lab, CD34, in HSPCs. This will provide us insight into novel roles for endomucin and E-selectin and help us to understand the factors influencing HSPC migration to BM endothelium.

Acute hypertriglyceridemia induces platelet hyperactivity that is not attenuated by insulin in polycystic ovary syndrome.

Science.gov (United States)

Aye, Myint Myint; Kilpatrick, Eric S; Aburima, Ahmed; Wraith, Katie S; Magwenzi, Simbarashe; Spurgeon, B; Rigby, Alan S; Sandeman, Derek; Naseem, Khalid M; Atkin, Stephen L

2014-02-28

Atherothrombosis is associated with platelet hyperactivity. Hypertriglyceridemia and insulin resistance (IR) are features of polycystic ovary syndrome (PCOS). The effect of induced hypertriglyceridemia on IR and platelet function was examined in young women with PCOS. Following overnight fasting, 13 PCOS and 12 healthy women were infused with saline or 20% intralipid for 5 hours on separate days. Insulin sensitivity was measured using a hyperinsulinemic euglycaemic clamp in the final 2 hours of each infusion. Platelet responses to adenosine diphosphate (ADP) and prostacyclin (PGI2) were measured by flow cytometric analysis of platelet fibrinogen binding and P-selectin expression using whole blood taken during each infusion (at 2 hours) and at the end of each clamp. Lipid infusion increased triglycerides and reduced insulin sensitivity in both controls (median, interquartile range ) (5.25 [3.3, 6.48] versus 2.60 [0.88, 3.88] mg kg(-1) min(-1), P<0.001) and PCOS (3.15 [2.94, 3.85] versus 1.06 [0.72, 1.43] mg kg(-1) min(-1), P<0.001). Platelet activation by ADP was enhanced and ability to suppress platelet activation by PGI2 diminished during lipid infusion in both groups when compared to saline. Importantly, insulin infusion decreased lipid-induced platelet hyperactivity by decreasing their response to 1 μmol/L ADP (78.7% [67.9, 82.3] versus 62.8% [51.8, 73.3], P=0.02) and increasing sensitivity to 0.01 μmol/L PGI2 (67.6% [39.5, 83.8] versus 40.9% [23.8, 60.9], P=0.01) in controls, but not in PCOS. Acute hypertriglyceridemia induced IR, and increased platelet activation in both groups that was not reversed by insulin in PCOS subjects compared to controls. This suggests that platelet hyperactivity induced by acute hypertriglyceridemia and IR could contribute athero-thrombotic risk. www.isrctn.org. Unique Identifier: ISRCTN42448814.

[The study of anticoagulants selection in platelet-rich plasma preparation].

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Hua, Lei; Lai, Gui; Zhenjun, Liu; Guie, Ma

2015-07-01

To investigate the effect of the anticoagulants on PRP quality, so as to clarify the appropriate anticoagulant used in PRP production. The microstructure change of platelets collected via heparin, citrate, acid citrate dextrose (ACD) and citrate-theophylline-adenosine-dipyridamole ( CTAD) was observed by TEM following time course. The extent of spontaneous activation of platelets in four groups was detected by measuring sP-selectin in plasma. The TGF-β1 release amount of activated PRP of four groups was measured. CTAD is superior to other anticoagulants in maintaining the integrity of platelet structures for a long time and preventing platelet spontaneous activation. ACD slightly surpassed heparin and citrate in above two aspects. ACD-PRP and CTAD-PRP released significantly more TGF-β1 compared with heparin and citrate. The PRP quality and biological effects were strongly associated with the type of Anticoagulants. ACD and CTAD are optimal anticoagulants in PRP production for they can maintain platelet viability at a high level.

Lymphocyte-platelet crosstalk in Graves' disease.

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Kuznik, Boris I; Vitkovsky, Yuri A; Gvozdeva, Olga V; Solpov, Alexey V; Magen, Eli

2014-03-01

Platelets can modulate lymphocytes' role in the pathophysiology of thyroid autoimmune diseases. The present study was performed to clarify the status of platelet-lymphocyte subpopulations aggregation in circulating blood in patients with Graves' disease (GD). One hundred and fifty patients with GD (GD group) and 45 hyperthyroid patients with toxic multinodular goiter (TMG group) were recruited in the study. Control group consisted 150 healthy subjects. Immunophenotyping of lymphocytes was performed by flow cytometry. Detection of lymphocyte-platelet aggregates (LPAs) was done using light microscope after Ficoll-gradient centrifugation. The group of GD patients exhibited reduced CD8 lymphocyte and higher CD19 cell counts compared with TMG group and healthy controls. A greater number of activated CD3, HLA-DR+ lymphocytes were observed in GD than in TMG group and control group. GD group was characterized by lower blood platelet count (232 ± 89 × 10 cells/µL) than TMG group (251 ± 97 × 10 cells/µL; P TMG group (116 ± 67/µL, P < 0.005) and control group (104 ± 58 /µL; P < 0.001). GD is associated with higher levels of activated lymphocytes and lymphocyte-platelet aggregates.

Reduced blood brain barrier breakdown in P-selectin deficient mice following transient ischemic stroke: a future therapeutic target for treatment of stroke

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Petterson Jodie

2010-02-01

Full Text Available Abstract Background The link between early blood- brain barrier (BBB breakdown and endothelial cell activation in acute stroke remain poorly defined. We hypothesized that P-selectin, a mediator of the early phase of leukocyte recruitment in acute ischemia is also a major contributor to early BBB dysfunction following stroke. This was investigated by examining the relationship between BBB alterations following transient ischemic stroke and expression of cellular adhesion molecule P-selectin using a combination of magnetic resonance molecular imaging (MRMI, intravital microscopy and immunohistochemistry. MRMI was performed using the contrast, gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA conjugated to Sialyl Lewis X (Slex where the latter is known to bind to activated endothelium via E- or P selectins. Middle cerebral artery occlusion was induced in male C57/BL 6 wild-type (WT mice and P-selectin-knockout (KO mice. At 24 hours following middle cerebral artery occlusion, T1 maps were acquired prior to and following contrast injection. In addition to measuring P- and E-selectin expression in brain homogenates, alterations in BBB function were determined immunohistochemically by assessing the extravasation of immunoglobulin G (IgG or staining for polymorphonuclear (PMN leukocytes. In vivo assessment of BBB dysfunction was also investigated optically using intravital microscopy of the pial circulation following the injection of Fluorescein Isothiocyanate (FITC-dextran (MW 2000 kDa. Results MRI confirmed similar infarct sizes and T1 values at 24 hours following stroke for both WT and KO animals. However, the blood to brain transfer constant for Gd DTPA (Kgd demonstrated greater tissue extravasation of Gd DTPA in WT animals than KO mice (P 1 stroke -Δ T1 contralateral control cortex, decreased significantly in the Gd-DTPA(sLeX group compared to Gd-DTPA, indicative of sLeX mediated accumulation of the targeted contrast agent. Regarding BBB

Collagen can selectively trigger a platelet secretory phenotype via glycoprotein VI.

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Véronique Ollivier

Full Text Available Platelets are not only central actors of hemostasis and thrombosis but also of other processes including inflammation, angiogenesis, and tissue regeneration. Accumulating evidence indicates that these "non classical" functions of platelets do not necessarily rely on their well-known ability to form thrombi upon activation. This suggests the existence of non-thrombotic alternative states of platelets activation. We investigated this possibility through dose-response analysis of thrombin- and collagen-induced changes in platelet phenotype, with regards to morphological and functional markers of platelet activation including shape change, aggregation, P-selectin and phosphatidylserine surface expression, integrin activation, and release of soluble factors. We show that collagen at low dose (0.25 µg/mL selectively triggers a platelet secretory phenotype characterized by the release of dense- and alpha granule-derived soluble factors without causing any of the other major platelet changes that usually accompany thrombus formation. Using a blocking antibody to glycoprotein VI (GPVI, we further show that this response is mediated by GPVI. Taken together, our results show that platelet activation goes beyond the mechanisms leading to platelet aggregation and also includes alternative platelet phenotypes that might contribute to their thrombus-independent functions.

Role of focal adhesion tyrosine kinases in GPVI-dependent platelet activation and reactive oxygen species formation.

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Naadiya Carrim

Full Text Available We have previously shown the presence of a TRAF4/p47phox/Hic5/Pyk2 complex associated with the platelet collagen receptor, GPVI, consistent with a potential role of this complex in GPVI-dependent ROS formation. In other cell systems, NOX-dependent ROS formation is facilitated by Pyk2, which along with its closely related homologue FAK are known to be activated and phosphorylated downstream of ligand binding to GPVI.To evaluate the relative roles of Pyk2 and FAK in GPVI-dependent ROS formation and to determine their location within the GPVI signaling pathway.Human and mouse washed platelets (from WT or Pyk2 KO mice were pre-treated with pharmacological inhibitors targeting FAK or Pyk2 (PF-228 and Tyrphostin A9, respectively and stimulated with the GPVI-specific agonist, CRP. FAK, but not Pyk2, was found to be essential for GPVI-dependent ROS production and aggregation. Subsequent human platelet studies with PF-228 confirmed FAK is essential for GPVI-mediated phosphatidylserine exposure, α-granule secretion (P-selectin (CD62P surface expression and integrin αIIbβ3 activation. To determine the precise location of FAK within the GPVI pathway, we analyzed the effect of PF-228 inhibition in CRP-stimulated platelets in conjunction with immunoprecipitation and pulldown analysis to show that FAK is downstream of Lyn, Spleen tyrosine kinase (Syk, PI3-K and Bruton's tyrosine kinase (Btk and upstream of Rac1, PLCγ2, Ca2+ release, PKC, Hic-5, NOX1 and αIIbβ3 activation.Overall, these data suggest a novel role for FAK in GPVI-dependent ROS formation and platelet activation and elucidate a proximal signaling role for FAK within the GPVI pathway.

Immunologic changes in TNF-alpha, sE-selectin, sP-selectin, sICAM-1, and IL-8 in pediatric patients treated for psoriasis with the Goeckerman regimen

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Borska, L.; Fiala, Z.; Krejsek, J.; Andrys, C.; Vokurkova, D.; Hamakova, K.; Kremlacek, J.; Ettler, K. [Charles University of Prague, Hradec Kralove (Czech Republic). Faculty of Medicine

2007-11-15

Psoriasis is a chronic inflammatory skin disease which is often manifested during childhood. The present study investigated changes in the serum levels of proinflammatory cytokines and soluble forms of adhesion molecules in children with psoriasis. The observed patient group of 26 children was treated with the Goeckerman regimen. This therapy combines dermal application of crude coal tar with ultraviolet radiation. The Psoriasis Area Severity Index decreased significantly after treatment by with the Goeckerman regimen (p < 0.001). Serum levels of the proinflammatory cytokine TNF-alpha and adhesion molecules sICAM-1, sP-selectin and sE-selectin decreased after the Goeckerman regimen. The TNF-alpha and sICAM-1 decreased significantly (p < 0.05). Our findings support the complex role of these immune parameters in the immunopathogenesis of psoriasis in children. The serum level of IL-8 increased after the Goeckerman regimen. This fact indicates that the chemokine pathway of IL-8 activity could be modulated by this treatment, most likely by polycyclic aromatic hydrocarbons.

Modeling HIV-1 Induced Neuroinflammation in Mice: Role of Platelets in Mediating Blood-Brain Barrier Dysfunction.

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Letitia D Jones

Full Text Available The number of HIV-1 positive individuals developing some form of HIV-associated neurocognitive disorder (HAND is increasing. In these individuals, the integrity of the blood-brain barrier (BBB is compromised due to an increase in exposure to pro-inflammatory mediators, viral proteins, and virus released from infected cells. It has been shown that soluble CD40L (sCD40L is released upon platelet activation and is an important mediator of the pathogenesis of HAND but the underlying mechanisms are unclear, emphasizing the need of an effective animal model. Here, we have utilized a novel animal model in which wild-type (WT mice were infected with EcoHIV; a derivative of HIV-1 that contains a substitution of envelope protein gp120 with that of gp80 derived from murine leukemia virus-1 (MuLV-1. As early as two-weeks post-infection, EcoHIV led to increased permeability of the BBB associated with decreased expression of tight junction protein claudin-5, in CD40L and platelet activation-dependent manner. Treatment with an antiplatelet drug, eptifibatide, in EcoHIV-infected mice normalized BBB function, sCD40L release and platelet activity, thus implicating platelet activation and platelet-derived CD40L in virally induced BBB dysfunction. Our results also validate and underscore the importance of EcoHIV infection mouse model as a tool to explore therapeutic targets for HAND.

Efficacy of Clopidogrel and Clinical Outcome When Clopidogrel Is Coadministered With Atorvastatin and Lansoprazole

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Zhang, Jian-rong; Wang, Di-qing; Du, Jun; Qu, Guang-su; Du, Jian-lin; Deng, Song-bai; Liu, Ya-jie; Cai, Jin-xi; She, Qiang

2015-01-01

Abstract This prospective, randomized, nonblind, controlled trial evaluated the effects of clopidogrel on platelet function upon coadministration with atorvastatin and lansoprazole. One hundred four adult patients with non-ST-segment elevated acute coronary syndrome (NSTE-ACS) who underwent percutaneous coronary intervention (PCI) with drug-eluting stent implantation were included. All patients were treated with standard dual antiplatelet therapy (DAPT) plus rosuvastatin 10 mg daily after the operation. On the sixth day after PCI, patients were randomly divided into 4 groups, Group A: DAPT + atorvastatin 20 mg daily (a change from rosuvastatin to atorvastatin) + lansoprazole 30 mg daily, Group B: DAPT + atorvastatin 20 mg daily (a change from rosuvastatin to atorvastatin), Group C: DAPT + lansoprazole 30 mg daily (continuing to take rosuvastatin), Group D is the control group. Additional drugs were used according to the situation of patients. Platelet function and concentrations of platelet activation markers (granular membrane protein 140 (P-selectin), thromboxane B2 (TXB2), and human soluble cluster of differentiation 40 ligand (sCD40L)) were assessed before randomization and at 15- and 30-day follow-up visits. All patients were maintained on treatment for 6 months and observed for bleeding and ischemic events. A total of 104 patients were enrolled, 27 patients in group A, 26 patients in Group B/C, 25 patients in Group D separately, and all the patients were analyzed. There were no differences in platelet function and the levels of platelet activation markers (P-selectin, TXB2, and sCD40L) among or within the 4 groups at the 3 time points of interest (P > 0.05). In the subsequent 6 months, no significant bleeding events occurred, and 12 patients experienced ischemic events, these results were also not significantly different among the groups (P > 0.05). In patients diagnosed with NSTE-ACS who have had drug-eluting stent

Platelet-rich plasma stimulated by pulse electric fields: Platelet activation, procoagulant markers, growth factor release and cell proliferation.

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Frelinger, A L; Torres, A S; Caiafa, A; Morton, C A; Berny-Lang, M A; Gerrits, A J; Carmichael, S L; Neculaes, V B; Michelson, A D

2016-01-01

Therapeutic use of activated platelet-rich plasma (PRP) has been explored for wound healing, hemostasis and antimicrobial wound applications. Pulse electric field (PEF) stimulation may provide more consistent platelet activation and avoid complications associated with the addition of bovine thrombin, the current state of the art ex vivo activator of therapeutic PRP. The aim of this study was to compare the ability of PEF, bovine thrombin and thrombin receptor activating peptide (TRAP) to activate human PRP, release growth factors and induce cell proliferation in vitro. Human PRP was prepared in the Harvest SmartPreP2 System and treated with vehicle, PEF, bovine thrombin, TRAP or Triton X-100. Platelet activation and procoagulant markers and microparticle generation were measured by flow cytometry. Released growth factors were measured by ELISA. The releasates were tested for their ability to stimulate proliferation of human epithelial cells in culture. PEF produced more platelet-derived microparticles, P-selectin-positive particles and procoagulant annexin V-positive particles than bovine thrombin or TRAP. These differences were associated with higher levels of released epidermal growth factor after PEF than after bovine thrombin or TRAP but similar levels of platelet-derived, vascular-endothelial, and basic fibroblast growth factors, and platelet factor 4. Supernatant from PEF-treated platelets significantly increased cell proliferation compared to plasma. In conclusion, PEF treatment of fresh PRP results in generation of microparticles, exposure of prothrombotic platelet surfaces, differential release of growth factors compared to bovine thrombin and TRAP and significant cell proliferation. These results, together with PEF's inherent advantages, suggest that PEF may be a superior alternative to bovine thrombin activation of PRP for therapeutic applications.

Impact of ticagrelor on P2Y1 and P2Y12 localization and on cholesterol levels in platelet plasma membrane.

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Rabani, Vahideh; Montange, Damien; Meneveau, Nicolas; Davani, Siamak

2017-10-11

Ticagrelor is an antiplatelet agent that inhibits platelet activation via P2Y12 antagonism. There are several studies showing that P2Y12 needs lipid rafts to be activated, but there are few data about how ticagrelor impacts lipid raft organization. Therefore, we aimed to investigate how ticagrelor could impact the distribution of cholesterol and consequently alter the organization of lipid rafts on platelet plasma membranes. We identified cholesterol-enriched raft fractions in platelet membranes by quantification of their cholesterol levels. Modifications in cholesterol and protein profiles (Flotillin 1, Flotillin 2, CD36, P2Y1, and P2Y12) were studied in platelets stimulated by ADP, treated by ticagrelor, or both. In ADP-stimulated and ticagrelor-treated groups, we found a decreased level of cholesterol in raft fractions of platelet plasma membrane compared to the control group. In addition, the peak of cholesterol in different experimental groups changed its localization on membrane fractions. In the control group, it was situated on fraction 2, while in ADP-stimulated platelets, it was located in fractions 3 to 5, and in fraction 4 in ticagrelor-treated group. The proteins studied also showed changes in their level of expression and localization in fractions of plasma membrane. Cholesterol levels of plasma membranes have a direct role in the organization of platelet membranes and could be modified by stimulation or drug treatment. Since ticagrelor and ADP both changed lipid composition and protein profile, investigating the lipid and protein composition of platelet membranes is of considerable importance as a focus for further research in anti-platelet management.

Molecular evaluation of thrombosis using X-ray phase contrast imaging with microbubbles targeted to P-selectin in mice

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Tang, Rongbiao; Chai, Wei-Min; Yan, Fuhua; Chen, Ke-Min; Yang, Guo-Yuan

2016-01-01

X-ray phase contrast imaging (PCI) provides excellent image contrast by utilizing the phase shift. The introduction of microbubbles into tissues can cause a phase shift to make microbubbles visibly identified on PCI. In this study, we assessed the feasibility of targeted microbubble-based PCI for the detection of thrombosis. The absorption and phase contrast images of P-selectin-targeted microbubbles (MB P ) were obtained and compared in vitro. MB P , control IgG-targeted microbubbles (MB C ), and unbound microbubbles (MB U ) were tested for binding specificity on thrombi expressing P-selectin. MB P were used as molecular PCI probes to evaluate P-selectin expression in a mouse model of arteriovenous shunt thrombosis that was created using PE tubes in the bypass outside of the mouse body. PCI clearly showed the microbubbles not viewable via absorption contrast imaging (ACI). In vitro attachment of MB P (91.60 ± 11.63) to thrombi was significantly higher than attachment of MB C (17.80 ± 4.02, P < 0.001) or MB U (9.80 ± 2.59, P < 0.001). In the mouse model of arteriovenous shunt thrombosis, the binding affinity of MB P (15.50 ± 6.25) was significantly greater than that of MB C (0.50 ± 0.84, P < 0.001) or MB U (0.33 ± 0.52, P < 0.001). Our results indicate that molecular PCI may be considered as a novel and promising imaging modality for the investigation of thrombosis. (orig.)

CXC-chemokine regulation and neutrophil trafficking in hepatic ischemia-reperfusion injury in P-selectin/ICAM-1 deficient mice

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Crockett Elahé T

2007-05-01

Full Text Available Abstract Background Neutrophil adhesion and migration are critical in hepatic ischemia and reperfusion injury (I/R. P-selectin and the intercellular adhesion molecule (ICAM-1 can mediate neutrophil-endothelial cell interactions, neutrophil migration, and the interactions of neutrophils with hepatocytes in the liver. Despite very strong preclinical data, recent clinical trials failed to show a protective effect of anti-adhesion therapy in reperfusion injury, indicating that the length of injury might be a critical factor in neutrophil infiltration. Therefore, the aim of this study was to assess the role of P-selectin and ICAM-1 in neutrophil infiltration and liver injury during early and late phases of liver I/R. Methods Adult male wild-type and P-selectin/ICAM-1-deficient (P/I null mice underwent 90 minutes of partial liver ischemia followed by various periods of reperfusion (6, 15 h, and a survival study. Liver injury was assessed by plasma level of alanine aminotransferase (ALT and histopathology. The plasma cytokines, TNF-α, IL-6, MIP-2 and KC, were measured by ELISA. Results Reperfusion caused significant hepatocellular injury in both wild-type and P/I null mice as was determined by plasma ALT levels and liver histopathology. The injury was associated with a marked neutrophil infiltration into the ischemic livers of both wild-type and P/I null mice. Although the levels of ALT and neutrophil infiltration were slightly lower in the P/I null mice compared with the wild-type mice the differences were not statistically significant. The plasma cytokine data of TNF-α and IL-6 followed a similar pattern to ALT data, and no significant difference was found between the wild-type and P/I null groups. In contrast, a significant difference in KC and MIP-2 chemokine levels was observed between the wild-type and P/I null mice. Additionally, the survival study showed a trend towards increased survival in the P/I null group. Conclusion While ICAM-1 and P-selectin

Platelets and hemophilia: A review of the literature.

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Riedl, Julia; Ay, Cihan; Pabinger, Ingrid

2017-07-01

Hemophilia A and B are inherited bleeding disorders due to deficiencies of the clotting factors VIII and IX, respectively. The severity of the disease correlates with remaining factor levels, although individual differences in bleeding tendency are seen despite similar factor levels. While thrombin generation is severely impaired in persons with hemophilia, primary hemostasis, i.e. platelet function, has been generally considered to be normal. However, some studies reported prolonged bleeding times in hemophilia, suggesting that also primary hemostasis is affected. In several other studies different aspects of platelet function in hemophilia have been investigated in more detail and various alterations were discovered, such as increased platelet P-selectin expression, a lower number of procoagulant, so-called 'coated' platelets, lower aggregation upon co-incubation with tissue factor, or reduced platelet contractile forces during clot formation in comparison to healthy individuals. An influence of platelet function on clinical phenotype was suggested, which might contribute in part to variations in bleeding tendency in hemophilic patients with similar factor levels. However, the available evidence is currently limited and no clear correlations between platelet function parameters and clinical phenotypes have been demonstrated. The impact of alterations of platelet function in hemophilia remains to be better defined. Another interesting role of platelets in hemophilia has been reported recently by establishing a novel gene-therapeutic strategy using platelets as a delivery system for FVIII, showing promising results in animal models. This review gives an overview on the currently published literature on platelet function and the potential roles of platelets in hemophilia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Platelet inhibition by nitrite is dependent on erythrocytes and deoxygenation.

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Sirada Srihirun

Full Text Available Nitrite is a nitric oxide (NO metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet activity was investigated.Platelet aggregation was studied in platelet-rich plasma (PRP and PRP+erythrocytes by turbidimetric and impedance aggregometry, respectively. In PRP, DEANONOate inhibited platelet aggregation induced by ADP while nitrite had no effect on platelets. In PRP+erythrocytes, the inhibitory effect of DEANONOate on platelets decreased whereas nitrite at physiologic concentration (0.1 µM inhibited platelet aggregation and ATP release. The effect of nitrite+erythrocytes on platelets was abrogated by C-PTIO (a membrane-impermeable NO scavenger, suggesting an NO-mediated action. Furthermore, deoxygenation enhanced the effect of nitrite as observed from a decrease of P-selectin expression and increase of the cGMP levels in platelets. The ADP-induced platelet aggregation in whole blood showed inverse correlations with the nitrite levels in whole blood and erythrocytes.Nitrite alone at physiological levels has no effect on platelets in plasma. Nitrite in the presence of erythrocytes inhibits platelets through its reduction to NO, which is promoted by deoxygenation. Nitrite may have role in modulating platelet activity in the circulation, especially during hypoxia.

Immune regulation by CD40-CD40-l interactions - 2; Y2K update.

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van Kooten, C

2000-11-01

CD40 is a cell surface receptor, which belongs to the TNF-R family, and which was first identified and functionally characterized on B lymphocytes. However, in recent years it has become clear that CD40 is expressed much broader, including expression on monocytes, dendritic cells, endothelial cells and epithelial cells. Therefore it is now thought that CD40 plays a more general role in immune regulation. The present paper reviews recent developments in this field of research, with main emphasis on CD40 signal transduction and on in vivo functions of CD40/CD40-L interactions.

Platelet adhesion and degranulation induce pro-survival and pro-angiogenic signalling in ovarian cancer cells.

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Karl Egan

Full Text Available Thrombosis is common in ovarian cancer. However, the interaction of platelets with ovarian cancer cells has not been critically examined. To address this, we investigated platelet interactions in a range of ovarian cancer cell lines with different metastatic potentials [HIO-80, 59M, SK-OV-3, A2780, A2780cis]. Platelets adhered to ovarian cancer cells with the most significant adhesion to the 59M cell line. Ovarian cancer cells induced platelet activation [P-selectin expression] in a dose dependent manner, with the most significant activation seen in response to the 59M cell line. The platelet antagonists [cangrelor, MRS2179, and apyrase] inhibited 59M cell induced activation suggesting a P2Y12 and P2Y1 receptor mediated mechanism of platelet activation dependent on the release of ADP by 59M cells. A2780 and 59M cells potentiated PAR-1, PAR-4, and TxA2 receptor mediated platelet activation, but had no effect on ADP, epinephrine, or collagen induced activation. Analysis of gene expression changes in ovarian cancer cells following treatment with washed platelets or platelet releasate showed a subtle but valid upregulation of anti-apoptotic, anti-autophagy pro-angiogenic, pro-cell cycle and metabolic genes. Thus, ovarian cancer cells with different metastatic potential adhere and activate platelets differentially while both platelets and platelet releasate mediate pro-survival and pro-angiogenic signals in ovarian cancer cells.

Isolation and characterization of N-feruloyltyramine as the P-selectin expression suppressor from garlic (Allium sativum)

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Because garlic (Allium sativum) is believed to have positive health effects on cardiovascular disease, the screening of isolated fractions from a garlic extract against cardiovascular disease related-processes should help identify active compounds. Both P-selectin expression suppressing activity ag...

The multi-functionality of CD40L and its receptor CD40 in atherosclerosis

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Lievens, Dirk; Eijgelaar, Wouter J.; Biessen, Erik A. L.; Daemen, Mat J. A. P.; Lutgens, Esther

2009-01-01

Disrupting the CD40-CD40L co-stimulatory pathway reduces atherosclerosis and induces a stable atherosclerotic plaque phenotype that is low in inflammation and high in fibrosis. Therefore, inhibition of the CD40-CD40L pathway is an attractive therapeutic target to reduce clinical complications of

[Changes of CD34(+) and CD71(+)CD45(-) cell levels in bone marrow of MDS and AA patients].

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Yan, Zhen-Yu; Tian, Xu; Li, Ying; Yang, Mei-Rong; Zhang, Song; Wang, Xie-Ming; Zhang, Hai-Xia; Cheng, Nai-Yao

2014-04-01

This study was aimed to investigate the changes of CD34(+) and CD71(+)CD45(-) cell levels in MDS and AA patients. A total of 25 cases MDS and 43 cases of AA (18 cases SAA and 25 cases of NSAA) from January 2010 to October 2013 in the Department of Hematology, affiliated hospital of Hebei United University were enrolled in this study. The complete blood count, bone marrow smears, bone marrow biopsy, karyotype analysis and bone marrow blood cell immune genotyping (mainly the proportion of CD34(+) cells, CD71(+)CD45(-) cells in nucleated cells) were carried out for all patients; the changes of CD34(+) and CD71(+)CD45(-) cell levels in patients with MDS and AA (SAA NSAA) were compared; the differences of white blood cell count, platelet count and hemoglobin concentration in patients with count of CD71(+)CD45(-) ≥ 15% or MDS group was higher than that in AA (NSAA and SAA) group (P MDS group was higher than that in SAA (P MDS group. In MDS group with CD71(+)CD45(-) ≥ 15%, the platelet count was significantly higher than that in NSAA group (P MDS and NSAA group with CD71(+)CD45(-) 0.05). It is concluded that the count of CD34(+) cells in MDS patients is significantly higher than that in AA and SAA patients. The count of CD71(+)CD45(-) cells in MDS group is significantly higher than that of SAA group. The platelet count in MDS patients with CD71(+)CD45(-) cells ≥ 15% is significantly higher than that of the NSAA group.

Microvascular abnormalities in capillaroscopy correlate with higher serum IL-18 and sE-selectin levels in patients with type 1 diabetes complicated by microangiopathy

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Maria Górska

2011-04-01

Full Text Available Microvascular abnormalities are one of the most important causes of persistent diabetic complications. The aim of this study was to compare microvascular changes examined by nailfold capillaroscopy with serum concentrations of soluble E-selectin (sE-selectin and IL-18 in type 1 diabetic patients with and without microangiopathy. Serum levels of sE-selectin and IL-18 were determined by an enzyme-linked immunosorbent assay in 106 patients with type 1 diabetes and in 40 healthy controls. All diabetic patients were evaluated by extensive clinical, laboratory and capillaroscopic studies. Morphological changes were observed by nailfold capillaroscopy in 86 out of 106 (81% diabetic patients. Severe capillaroscopic changes were seen in 32 out of 54 (59% patients with microangiopathy, but in only seven out of 52 (13% patients without microangiopathy. Higher serum levels of sE-selectin (p < 0.001 and IL-18 (p < 0.05 were demonstrated in diabetic patients compared to controls. Significant differences of sE-selectin (p < 0.001 and IL-18 (p < 0.01 serum concentrations were observed between diabetic patients with microangiopathy and controls. Moreover, comparison between patients with and without microangiopathic complications showed a significantly higher capillaroscopic score and sE-selectin serum concentration in the group with microangiopathy (p < 0.001. Furthermore, diabetic patients with severe microvascular changes in capillaroscopy showed significantly higher IL-18 (p < 0.001 and sE-selectin (p < 0.05 serum levels than subgroups without changes or with mild abnormalities. Our findings suggest that abnormalities in nailfold capillaroscopy may reflect the extent of microvascular involvement and are associated with higher sE-selectin and IL-18 serum levels, as well as with microangiopathic complications in diabetic patients. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 1, pp. 104–110