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. 2000 Dec 5;97(25):13835-40.
doi: 10.1073/pnas.250475997.

Pro-coagulant state resulting from high levels of soluble P-selectin in blood

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Pro-coagulant state resulting from high levels of soluble P-selectin in blood

P André et al. Proc Natl Acad Sci U S A. .

Abstract

The plasma concentration of soluble adhesion receptors is increased under pathological circumstances, but their function remains enigmatic. Soluble P-selectin (sP-sel) is shed from activated platelets and endothelial cells. Mice genetically engineered to express P-selectin without the cytoplasmic tail (DeltaCT) constitutively show a 3- to 4-fold increase of sP-sel in plasma. We observed that the DeltaCT mice formed fibrin very readily. In an ex vivo perfusion chamber, there was more fibrin deposited at the site of platelet thrombus formation than in wild type (WT), whereas no fibrin deposits were detected using P-selectin-deficient blood during the same interval. Similarly, in vivo, the hemorrhage produced by local Shwartzman reaction was smaller in the DeltaCT mice than in WT. In contrast, we previously showed hemorrhage to be more prominent in P-selectin knock-out mice. Infusion of mouse P-sel-Ig chimera produced the same protective effect in WT mice as seen in the DeltaCT mice, indicating that the effect was due to increased levels of sP-sel. Mice infused with P-sel-Ig showed significantly more fibrin deposited on the luminal face of the injured vessels than control mice. Plasma from DeltaCT mice or mice infused with P-sel-Ig contained higher concentration of pro-coagulant microparticles and clotted one minute faster than WT. This pro-coagulant phenotype of DeltaCT mice could be reversed by a 4-day treatment with PSGL-Ig, a P-selectin inhibitor. We propose that sP-sel should no longer be considered only as a marker of inflammation or platelet activation, but also as a direct inducer of pro-coagulant activity associated with vascular and thrombotic diseases.

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Figures

Figure 1
Figure 1
Platelet and fibrin deposition in an ex vivo flow chamber. Representative photomicrographs are shown of collagen-coated capillaries exposed for 2 min to flow of non-anticoagulated blood from WT, P−/−, and ΔCT mice at shear rate of 212 s−1. White arrowheads point to platelet-rich thrombi formed on the collagen surface. Note the presence of long fibrin tails distal to the thrombi in the ΔCT perfusion chamber (black arrows). After a longer perfusion, some fibrin could be detected also with the P−/− blood. Blood flow was from left to right. Bar = 20 μm.
Figure 2
Figure 2
Effect of sP-sel on fibrin distribution at the Shwartzman reaction lesion site. (A) Micrographs showing fibrin deposition (F) in paraffin section from the Shwartzman lesion site. Tissue sections from WT mice treated with IgG1 or P-sel-Ig were immunostained with antibodies to fibrinogen. Note the presence of hemorrhage (H) in the section from the IgG1-treated animals, and a diffuse staining for fibrin inside and outside the vessel. A strong fibrin staining (F) is found on the luminal face of the vessel wall in the P-sel-Ig-treated mice, without detectable fibrin deposition in the surrounding tissue. White arrowheads point to the vessel wall. Bar = 40 μm. (B) Evaluation of fibrin localization relative to the vessel wall of all blood vessels observed in paraffin sections at the lesion site. “Leakage” annotates blood vessels that presented fibrin staining outside the vessel wall. Blood vessels that had fibrin staining only at the luminal face of the vessel wall were classified as “luminal ring.” The frequency of vessels showing leakage was 3-fold higher in WT mice treated with IgG1 than with P-sel-Ig (*, P < 0.0001). In contrast, the luminal ring was more common in the P-sel-Ig-treated group than in the IgG1 controls (†, P < 0.005). The counting was performed on samples from 7 mice injected with P-sel-Ig and from 10 mice injected with control IgG1. A minimum of 100 vessels were observed per lesion site.
Figure 3
Figure 3
sP-sel and plasma clotting time. Plasma were incubated at 37°C with an equal volume of a 20 mM CaCl2 solution and stirred at 800 rpm in an aggregometer cuvette to measure the clotting time. Increased levels of sP-sel found in plasma of either ΔCT mice (A) or WT mice treated with 1.2 μg/g body weight P-sel-Ig (B) significantly shortened the plasma clotting time.
Figure 4
Figure 4
Detection of Mac-1 and TF antigens at the surface of microparticles from WT and ΔCT mice by flow cytometry. Labeling of microparticles was performed with a rat monoclonal anti-murine macrophage Mac-1 antibody revealed by a phycoerythrin-conjugated goat anti-rat IgG, and a sheep anti-rabbit TF IgG revealed by a FITC-conjugated rabbit anti-sheep IgG. Control staining of microparticles from ΔCT mice was performed by using rat IgG and FITC-conjugated sheep IgG. A prominent population of doubly labeled microparticles is seen in samples from ΔCT mice. Figures are representative of three different experiments. TF-induced Xa activity was determined on the corresponding fraction of microparticles. The activity in samples from WT mice was 14.7 + 1.3 mOD/min, n = 5, and was significantly increased in ΔCT samples, 28.9 + 4.1 mOD/min, n = 5, P = 0.011.
Figure 5
Figure 5
PSGL-Ig infusion decreases the number of microparticles and prolongs the clotting time in plasma of ΔCT mice. (A) Number of microparticles present in 40 μl of ΔCT plasma, before (open bars) and after (filled bars) two infusions of PSGL-Ig and control-Ig as described in Materials and Methods. *, P < 0.05, determined by paired t test. (B) Clotting time of plasma obtained at the end of the experiment was significantly longer in mice treated with PSGL-Ig (filled bar) than in control-Ig-treated group (striated bar), P < 0.05.

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References

    1. Wagner D D. Thromb Haemost. 1993;70:105–110. - PubMed
    1. Dunlop L C, Skinner M P, Bendall L J, Favaloro E J, Castaldi P A, Gorman J J, Gamble J R, Vadas M A, Berndt M C. J Exp Med. 1992;175:1147–1150. - PMC - PubMed
    1. Mayadas T N, Johnson R C, Rayburn H, Hynes R O, Wagner D D. Cell. 1993;74:541–554. - PubMed
    1. Palabrica T, Lobb R, Furie B C, Aronovitz M, Benjamin C, Hsu Y M, Sajer S A, Furie B. Nature (London) 1992;359:848–851. - PubMed
    1. Johnston G I, Bliss G A, Newman P J, McEver R P. J Biol Chem. 1990;265:21381–21385. - PubMed

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