Plasma levels of P-selectin are determined by platelet turn-over and the P-selectin Thr715Pro polymorphism (original) (raw)
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Plasma P-selectin is increased in thrombotic platelet disorders
Blood
P-selectin is a 140-kD protein found in the a-granules of platelets and the Weibel-Palade bodies o f endothelial cells that on cell activation is expressed on the cell surface and also secreted into the plasma. The secreted form of P-selectin, like plasma P-selectin, differed from platelet membrane P-selectin in that its molecular mass was "3 kD lower under reducing conditions. Both the secreted and plasma forms of P-selectin contained cytoplasmic sequence as determined by Western blot analysis with an affinity-purified rabbit anti-P-selectin cytoplasmic peptide antibody, We have measured plasma P-selectin and j3thromboglobulin (BTG) concurrently in (1) patients with consumptive thrombotic disorders, including disseminated intravascular coagulation (DIC), heparin-induced thrombocytopenia (HIT), and thrombotic thrombocytopenic purpura (TTP)/haemolytic uremic syndrome (HUS); (2) pa-From the Centre for Thrombosis and Vascular Research, the
Clinical Chemistry, 2007
Methods: This study was a case-control study of 116 patients with confirmed recurrent VTE and at least 1 event of unprovoked deep venous thrombosis or pulmonary embolism, and 129 age-and sex-matched healthy individuals. We measured sP-selectin by ELISA and P-selectin gene (SELP) variation by genotyping and sampled blood after a mean interval of 2.55 years after the most recent VTE event. Results: The mean (SD) sP-selectin concentration was higher in patients than in controls: 47.3 (15.0) g/L vs 36.8 (11.0) g/L, P <0.001. The unadjusted odds ratio (OR) for sP-selectin >55.1 g/L, representing the 95th percentile for controls, was 8.5 (95% CI, 3.7-23.3; P <0.001) and increased after adjustment for factor V Leiden, the prothrombin G20210A variant, increased factor VIII, and hyperhomocysteinemia (OR, 10.6; 95% CI, 4.1-31.2; P <0.001). Pro715 carriers were more prevalent among controls than patients (21.7% vs 14.7%). sP-selectin concentrations were lower in this subgroup than in noncarriers: 31.3 (7.9) g/L vs 44.1 (14.1) g/L; P <0.001). Conclusions: Increased sP-selectin concentrations are associated with VTE and genotype status. sP-selectin concentrations are lower in individuals carrying the P-selectin Pro715 variant than in those without this variant.
Journal of Immunological Methods, 1997
Adhesion molecules such as P-selectin are potential markers for evaluating platelet activation and studying the role of cell-cell interactions in numerous biological processes related to hemostasis and inflammation. The expression of P-selectin and related molecules has previously been quantified with different techniques. As an alternative to the most common method. 110~ cytometry, we have developed a useful ELISA method to simultaneously analyse 96 samples for platelet expression of P-selectin. Samples may be stored for at least 7 days at 4°C prior to analysis. The method is simple. reproducible, flexible and requires only standard equipment. Washed platelets (WP) from healthy male volunteers, at a concentration of 1 x lO'/microtiter plate well, were stimulated with various known platelet activators and fixed with 0.1% formaldehyde for IO min. The fixed WP were centrifuged to form a confluent layer in the wells and then incubated with optimal dilutions of primary antibodies (l/20001 directed against P-selectin, CD41, CD9 and secondary antibodies conjugated with alkaline phosphatase. Our results show that P-selectin expression on WP increases significantly upon stimulation with thrombin (0.1-1.0 U/ml), ADP (10 PM) and epinephrine (100 PM). The induction of P-selectin expression by thrombin is fast and has different kinetics depending on the concentration of the agonist. Prior incubation with the nitric oxide donor SNAP (10 PM) inhibits the up-regulation of P-selectin induced by sub-maximal concentrations of thrombin ( p < 0.051. This ELISA is suitable for studying the expression and regulation of P-selectin and other surface molecules on human platelets in various pathological states.
Clinical & Laboratory Haematology, 2000
P-selectin is an adhesion molecule found in the alpha granules of platelets. Activation occurs in response to a range of in¯ammatory and thrombotic agents resulting in rapid up-regulation. Flow cytometry methods have recently been described for the analysis of platelet P-selectin expression in whole blood. While introducing these methods into our laboratory it was noted that expression could be stimulated, in vitro, in a number of ways. This study shows that red cell lysis, the anticoagulant K 3 EDTA and the time elapse between blood collection and antibody labelling had statistically signi®cant effects on P-selectin expression. Post-labelling ®xation, with CellFIX, caused no signi-®cant effect. We conclude that blood for P-selectin analysis should be collected in sodium citrate and that red cell lysis and centrifugation should be avoided. When comparing samples, the time between collection and labelling should be standardized. The relatively high CV for the assay indicates that all samples should be labelled and analysed in duplicate with the mean level reported.
Journal of thee Medical Sciences (Berkala Ilmu Kedokteran), 2017
Thrombocyte concentrate (TC) transfusion is an important supportive therapy in patients with thrombocytopenia. The risks in platelet transfusions may be related to the content of TC including the contaminant leukocytes. The aim of this study was to assess the risk of increased level of P-Selectin (CD62P) expression of non-leukodepleted TC transfusions. This was a quasi-experimental study. Subjects were children patients aged 1-18 years who received a non-leukodepleted or a leukodepleted TC transfusions. Comparison of the proportion of increased expression of CD62P in both groups expressed as relative risk. The subjects consisted of 51 patients who received non-leukodepleted and 52 patients who received leukodepleted TC transfusions. The risk of increased expression of CD62P in patients receiving non-leukodepleted TC transfusions were 2.38 (95%CI:1.60-3.53) times higher than those who received leukodepleted TC. Non-leukodepleted have significant higher risks of increased CD62P expression than leukodepleted TC transfusions.
Cells
Defined as an index of platelet size heterogeneity, the platelet distribution width (PDW) is still a poorly characterized marker of platelet function in (sub)clinical disease. We presently validated PDW as a marker of P-selectin dependent platelet activation in the Moli-family cohort. Platelet-bound P-selectin and platelet/leukocyte mixed aggregates were measured by flow cytometry in freshly collected venous blood, both before and after in vitro platelet activation, and coagulation time was assessed in unstimulated and LPS- or TNFα-stimulated whole blood. Closure Times (CT) were measured in a Platelet Function Analyzer (PFA)-100. Multivariable linear mixed effect regression models (with age, sex and platelet count as fixed and family structure as random effect) revealed PDW to be negatively associated with platelet P-selectin, platelet/leukocyte aggregates and von Willebrand factor (VWF), and positively with PFA-100 CT, and LPS- and TNF-α-stimulated coagulation times. With the excep...
The emerging value of P-selectin as a disease marker
Clinical Chemistry and Laboratory Medicine (CCLM), 2004
Activated platelets are key components in many arterial disorders. P-selectin is an activation-dependent platelet receptor, which is also identified in endothelial cells. Together with E-and L-selectin it constitutes the selectin family. These transmembrane proteins have continued to attract great interest as they support rapid and reversible cell adhesion in flow systems and thus play an essential role in multicellular interactions during thrombosis and inflammation. Similarly to other lectins, selectins bind to different glycoconjugates with varying affinities. Protein ligands, equipped with the appropriate carbohydrate and sulfate moieties for P-selectin binding, have been identified in normal peripheral blood leukocytes and several non-hematopoietic organs, as well as on cancer cells. For diagnostic purposes, P-selectin can readily be detected on the platelet surface by flow cytometry and by ELISA as a soluble ligand in the plasma. Along with other markers, these data can be use...
Stroke, 2002
Background and Purpose-The increased risk of stroke and thromboembolism in atrial fibrillation (AF) may be related to a prothrombotic or hypercoagulable state, with abnormalities of hemostasis and platelet activation. To investigate the role of platelets in AF and the influence of antithrombotic therapy, we developed and then applied a new assay to detect the absolute amount of P-selectin per platelet (pP-selectin) based on cell lysis. Thus, pP-selectin in AF patients was compared with that of healthy controls and also with plasma soluble P-selectin (sP-selectin) and -thromboglobulin as established indices of platelet activation. Methods-We studied 122 patients (mean [SD] age, 71 [9] years; 65 men) with chronic AF of Ͼ6 weeks' duration: 34 were not on antithrombotic therapy, 30 were taking aspirin (75 to 300 mg/d), and 58 were fully anticoagulated with warfarin. pP-selectin was compared with sP-selectin and plasma -thromboglobulin levels (enzyme-linked immunosorbent assay). Results were compared with those of 23 healthy controls (mean [SD] age, 74 [9] years; 7 men) in sinus rhythm. Results-pP-selectin was significantly lower in AF patients on no antithrombotic therapy (Pϭ0.03) than in healthy controls, but sP-selectin and -thromboglobulin levels were not significantly different and did not differ in patients taking aspirin or warfarin. However, pP-selectin was lower in patients with AF on aspirin than in those on warfarin (PϽ0.05). pP-selectin/sP-selectin correlated significantly in healthy controls (rϭ0.47, Pϭ0.03) but inversely (rϭϪ0.43, Pϭ0.03) in AF patients on no antithrombotic therapy. Conclusions-Lower levels of pP-selectin may represent a depletion of pP-selectin after platelet activation in AF. Aspirin further decreases pP-selectin levels compared with warfarin. On the basis of the principle of platelet lysis, we demonstrate that it is possible to determine the amount of P-selectin per platelet, which may be regulated in the megakaryocyte through a cyclooxygenase-dependent pathway. (Stroke. 2002;33:1237-1242.)