Prevention of platelet-polymorphonuclear leukocyte interactions: New clues to the antithrombotic properties of parnaparin, a low molecular weight heparin

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Abstract

Background and Objectives. Heparin might possess anti-thrombotic properties other than anticoagulation. The aim of the present study was to test the effects of a low-molecular weight heparin, parnaparin, on adhesive molecule-mediated platelet-polymorphonuclear (PMN) leukocyte interactions and on PMN function. Design and Methods. Platelets and PMN were isolated from citrated blood from healthy subjects. Pre-activated platelets incubated with PMN under dynamic conditions formed mixed cell aggregates. In previous experiments PMN were stimulated in vitro by purified P-selectin or formyl-methionyl-leucyl- phenylalanine (fMLP). Dual color flow cytometry was used to detect the formation of platelet-PMN mixed cell aggregates, and PMN activation was tested for by measuring L-selectin shedding, tissue factor expression and PMN degranulation. The effect of parnaparin was compared to that of unfractionated heparin. Results. Parnaparin, at a concentration of 0.3-0.8 IUaXa/mL, inhibited the formation of mixed cell aggregates (48.8±9.7% of total PMN population) by up to 60% in a concentration-dependent manner, while heparin inhibited aggregation up to 40%. Parnaparin, (0.3-0.8 IUaXa/mL), prevented L-selectin shedding from PMN, which was induced by purified P-selectin (5 μg/mL) or fMLP (0.5 μmol/L) by 65% and 67%, respectively. Inhibition was independent of incubation time (5-20 min). Parnaparin (0.8 IUaXa/mL) also inhibited tissue factor expression on PMN (% of positive cells), which was induced by P-selectin or fMLP (185±10 and 241±80% of basal value, respectively). Parnaparin protected PMN from degranulation after challenge with either stimulus (>95% inhibition). All the effects of parnaparin were observed with heparin at similar concentrations, although to a lesser extent and were often not significantly different from events in controls. Interpretations and Conclusions. In conclusion, the process of depolymerization of heparin to obtain low molecular weight parnaparin resulted in an increased, anticoagulant- independent effect on PMN function. Thus, the overall anti-thrombotic properties of parnaparin may be partly due to a leukocyte-mediated anti-inflammatory effect.

Original languageEnglish
Pages (from-to)833-839
Number of pages7
JournalHaematologica
Volume90
Issue number6
Publication statusPublished - Jun 2005

Fingerprint

Low Molecular Weight Heparin
Neutrophils
Blood Platelets
Heparin
methionyl-leucyl-phenylalanine
P-Selectin
L-Selectin
Thromboplastin
parnaparin
Adhesives
Anticoagulants
Healthy Volunteers
Flow Cytometry
Leukocytes
Anti-Inflammatory Agents
Color
Molecular Weight

Keywords

  • Inflammation
  • Low-molecular weight heparin
  • Parnaparin
  • Platelet-PMN interaction
  • Selectins

ASJC Scopus subject areas

  • Hematology

Cite this

@article{30e64e00b3584345beed018d957c493f,
title = "Prevention of platelet-polymorphonuclear leukocyte interactions: New clues to the antithrombotic properties of parnaparin, a low molecular weight heparin",
abstract = "Background and Objectives. Heparin might possess anti-thrombotic properties other than anticoagulation. The aim of the present study was to test the effects of a low-molecular weight heparin, parnaparin, on adhesive molecule-mediated platelet-polymorphonuclear (PMN) leukocyte interactions and on PMN function. Design and Methods. Platelets and PMN were isolated from citrated blood from healthy subjects. Pre-activated platelets incubated with PMN under dynamic conditions formed mixed cell aggregates. In previous experiments PMN were stimulated in vitro by purified P-selectin or formyl-methionyl-leucyl- phenylalanine (fMLP). Dual color flow cytometry was used to detect the formation of platelet-PMN mixed cell aggregates, and PMN activation was tested for by measuring L-selectin shedding, tissue factor expression and PMN degranulation. The effect of parnaparin was compared to that of unfractionated heparin. Results. Parnaparin, at a concentration of 0.3-0.8 IUaXa/mL, inhibited the formation of mixed cell aggregates (48.8±9.7{\%} of total PMN population) by up to 60{\%} in a concentration-dependent manner, while heparin inhibited aggregation up to 40{\%}. Parnaparin, (0.3-0.8 IUaXa/mL), prevented L-selectin shedding from PMN, which was induced by purified P-selectin (5 μg/mL) or fMLP (0.5 μmol/L) by 65{\%} and 67{\%}, respectively. Inhibition was independent of incubation time (5-20 min). Parnaparin (0.8 IUaXa/mL) also inhibited tissue factor expression on PMN ({\%} of positive cells), which was induced by P-selectin or fMLP (185±10 and 241±80{\%} of basal value, respectively). Parnaparin protected PMN from degranulation after challenge with either stimulus (>95{\%} inhibition). All the effects of parnaparin were observed with heparin at similar concentrations, although to a lesser extent and were often not significantly different from events in controls. Interpretations and Conclusions. In conclusion, the process of depolymerization of heparin to obtain low molecular weight parnaparin resulted in an increased, anticoagulant- independent effect on PMN function. Thus, the overall anti-thrombotic properties of parnaparin may be partly due to a leukocyte-mediated anti-inflammatory effect.",
keywords = "Inflammation, Low-molecular weight heparin, Parnaparin, Platelet-PMN interaction, Selectins",
author = "Norma Maugeri and {De Gaetano}, Giovanni and Miriam Barbanti and Donati, {Maria Benedetta} and Chiara Cerletti",
year = "2005",
month = "6",
language = "English",
volume = "90",
pages = "833--839",
journal = "Haematologica",
issn = "0390-6078",
publisher = "NLM (Medline)",
number = "6",

}

TY - JOUR

T1 - Prevention of platelet-polymorphonuclear leukocyte interactions

T2 - New clues to the antithrombotic properties of parnaparin, a low molecular weight heparin

AU - Maugeri, Norma

AU - De Gaetano, Giovanni

AU - Barbanti, Miriam

AU - Donati, Maria Benedetta

AU - Cerletti, Chiara

PY - 2005/6

Y1 - 2005/6

N2 - Background and Objectives. Heparin might possess anti-thrombotic properties other than anticoagulation. The aim of the present study was to test the effects of a low-molecular weight heparin, parnaparin, on adhesive molecule-mediated platelet-polymorphonuclear (PMN) leukocyte interactions and on PMN function. Design and Methods. Platelets and PMN were isolated from citrated blood from healthy subjects. Pre-activated platelets incubated with PMN under dynamic conditions formed mixed cell aggregates. In previous experiments PMN were stimulated in vitro by purified P-selectin or formyl-methionyl-leucyl- phenylalanine (fMLP). Dual color flow cytometry was used to detect the formation of platelet-PMN mixed cell aggregates, and PMN activation was tested for by measuring L-selectin shedding, tissue factor expression and PMN degranulation. The effect of parnaparin was compared to that of unfractionated heparin. Results. Parnaparin, at a concentration of 0.3-0.8 IUaXa/mL, inhibited the formation of mixed cell aggregates (48.8±9.7% of total PMN population) by up to 60% in a concentration-dependent manner, while heparin inhibited aggregation up to 40%. Parnaparin, (0.3-0.8 IUaXa/mL), prevented L-selectin shedding from PMN, which was induced by purified P-selectin (5 μg/mL) or fMLP (0.5 μmol/L) by 65% and 67%, respectively. Inhibition was independent of incubation time (5-20 min). Parnaparin (0.8 IUaXa/mL) also inhibited tissue factor expression on PMN (% of positive cells), which was induced by P-selectin or fMLP (185±10 and 241±80% of basal value, respectively). Parnaparin protected PMN from degranulation after challenge with either stimulus (>95% inhibition). All the effects of parnaparin were observed with heparin at similar concentrations, although to a lesser extent and were often not significantly different from events in controls. Interpretations and Conclusions. In conclusion, the process of depolymerization of heparin to obtain low molecular weight parnaparin resulted in an increased, anticoagulant- independent effect on PMN function. Thus, the overall anti-thrombotic properties of parnaparin may be partly due to a leukocyte-mediated anti-inflammatory effect.

AB - Background and Objectives. Heparin might possess anti-thrombotic properties other than anticoagulation. The aim of the present study was to test the effects of a low-molecular weight heparin, parnaparin, on adhesive molecule-mediated platelet-polymorphonuclear (PMN) leukocyte interactions and on PMN function. Design and Methods. Platelets and PMN were isolated from citrated blood from healthy subjects. Pre-activated platelets incubated with PMN under dynamic conditions formed mixed cell aggregates. In previous experiments PMN were stimulated in vitro by purified P-selectin or formyl-methionyl-leucyl- phenylalanine (fMLP). Dual color flow cytometry was used to detect the formation of platelet-PMN mixed cell aggregates, and PMN activation was tested for by measuring L-selectin shedding, tissue factor expression and PMN degranulation. The effect of parnaparin was compared to that of unfractionated heparin. Results. Parnaparin, at a concentration of 0.3-0.8 IUaXa/mL, inhibited the formation of mixed cell aggregates (48.8±9.7% of total PMN population) by up to 60% in a concentration-dependent manner, while heparin inhibited aggregation up to 40%. Parnaparin, (0.3-0.8 IUaXa/mL), prevented L-selectin shedding from PMN, which was induced by purified P-selectin (5 μg/mL) or fMLP (0.5 μmol/L) by 65% and 67%, respectively. Inhibition was independent of incubation time (5-20 min). Parnaparin (0.8 IUaXa/mL) also inhibited tissue factor expression on PMN (% of positive cells), which was induced by P-selectin or fMLP (185±10 and 241±80% of basal value, respectively). Parnaparin protected PMN from degranulation after challenge with either stimulus (>95% inhibition). All the effects of parnaparin were observed with heparin at similar concentrations, although to a lesser extent and were often not significantly different from events in controls. Interpretations and Conclusions. In conclusion, the process of depolymerization of heparin to obtain low molecular weight parnaparin resulted in an increased, anticoagulant- independent effect on PMN function. Thus, the overall anti-thrombotic properties of parnaparin may be partly due to a leukocyte-mediated anti-inflammatory effect.

KW - Inflammation

KW - Low-molecular weight heparin

KW - Parnaparin

KW - Platelet-PMN interaction

KW - Selectins

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M3 - Article

C2 - 15951297

AN - SCOPUS:21244480057

VL - 90

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JO - Haematologica

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