A Non Anti-coagulant Fraction of Heparin Inhibits Leukocyte Diapedesis into the Lung by an Effect on Platelets

TY - JOUR

T1 - A Non Anti-coagulant Fraction of Heparin Inhibits Leukocyte Diapedesis into the Lung by an Effect on Platelets

AU - Riffo-Vasquez, Yanira

AU - Somani, Alysha

AU - Man, Francis

AU - Amison, Richard

AU - Pitchford, Simon

AU - Page, Clive P

PY - 2016/10/1

Y1 - 2016/10/1

N2 - We have investigated whether the mechanism by which the non anticoagulant N-acetyl-de-O-sulphated-heparin (NSH) inhibits leukocyte infiltration is mediated by an effect on platelet function. We show that oral treatment with 2 doses of NSH significantly inhibits eosinophil and neutrophil recruitment into the lungs. Intravital microscopy analysis shows that NSH inhibits leukocyte and platelet diapedesis in the microcirculation of the cremaster muscle and also in the trachea. More importantly, there were a significantly lower number of leukocytes recruited into the lung in response to LPS in thrombocytopenic mice when transfused with platelets pre-treated with NSH in vitro when compared with mice transfused with untreated platelets. Using intravital analysis of the microvasculature of the cremaster muscle we have demonstrated that the reinfusion of activated platelets significantly re-established leukocyte diapedesis in response to LPS, but that this effect was not observed when platelets were pre-treated in vitro with NSH. Finally, we investigated whether the effect of NSH altered the expression of adhesion molecules on the surface of platelets and leukocytes in blood samples collected from mice orally treated with NSH. Our results demonstrate that NSH significantly inhibited the detection of P-selectin evaluated by flow cytometry, confirming that part of the anti-inflammatory action of NSH is via an effect on platelet function.

AB - We have investigated whether the mechanism by which the non anticoagulant N-acetyl-de-O-sulphated-heparin (NSH) inhibits leukocyte infiltration is mediated by an effect on platelet function. We show that oral treatment with 2 doses of NSH significantly inhibits eosinophil and neutrophil recruitment into the lungs. Intravital microscopy analysis shows that NSH inhibits leukocyte and platelet diapedesis in the microcirculation of the cremaster muscle and also in the trachea. More importantly, there were a significantly lower number of leukocytes recruited into the lung in response to LPS in thrombocytopenic mice when transfused with platelets pre-treated with NSH in vitro when compared with mice transfused with untreated platelets. Using intravital analysis of the microvasculature of the cremaster muscle we have demonstrated that the reinfusion of activated platelets significantly re-established leukocyte diapedesis in response to LPS, but that this effect was not observed when platelets were pre-treated in vitro with NSH. Finally, we investigated whether the effect of NSH altered the expression of adhesion molecules on the surface of platelets and leukocytes in blood samples collected from mice orally treated with NSH. Our results demonstrate that NSH significantly inhibited the detection of P-selectin evaluated by flow cytometry, confirming that part of the anti-inflammatory action of NSH is via an effect on platelet function.

U2 - 10.1165/rcmb.2015-0172OC

DO - 10.1165/rcmb.2015-0172OC

M3 - Article

C2 - 27181499

SN - 1044-1549

VL - 55

SP - 554

EP - 563

JO - American Journal of Respiratory Cell and Molecular Biology

JF - American Journal of Respiratory Cell and Molecular Biology

IS - 4

ER -