title: Irradiation increases the interactions of platelets with the endothelium in vivo: analysis by intravital microscopy.
abstract: Adhesion of platelets to the endothelium is believed to be a major factor contributing to thrombosis and vascular occlusion after radiotherapy or endovascular irradiation. In the present study, platelet-endothelium interactions were analyzed in vivo by intravital microscopy in mesenteric venules of mice according to three parameters: (1) platelet rolling, (2) platelet adhesion, and (3) the presence of platelet clusters. A 10-Gy total-body irradiation of mice resulted in an increase in the frequency of appearance of these three types of platelet-endothelium interactions in postcapillary venules 6 and 24 h after exposure, whereas only minor alterations were seen in large venules. In addition, the duration of platelet adhesion was increased 24 h after irradiation in both postcapillary and large venules. However, P-selectin was not up-regulated on the platelet membrane and platelet-leukocytes were not seen rolling together, suggesting that changes in platelet-endothelial cell interaction result from endothelial cell activation rather than platelet activation. Our data suggest that irradiation transforms resting endothelial cells to a pro-adhesive surface for platelets, which could ultimately lead to thrombosis.
authors.affiliation: Institut de Radioprotection et de Sûreté Nucléaire, Fontenay-aux-Roses Cedex, France. marc-andre.mouthon@cea.fr
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Mouthon
authors.forename: Valérie
authors.initials: V
authors.lastname: Vereycken-Holler
authors.forename: Anne
authors.initials: A
authors.lastname: Van der Meeren
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Gaugler
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D001792:Blood Platelets / Q000473:pathology* / Q000528:radiation effects*; D002588:Cesium Radioisotopes; D004730:Endothelium, Vascular / Q000473:pathology* / Q000503:physiopathology / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015539:Platelet Activation / Q000528:radiation effects*; D010973:Platelet Adhesiveness / Q000528:radiation effects; D014699:Venules / Q000473:pathology / Q000503:physiopathology / Q000528:radiation effects; D014916:Whole-Body Irradiation
chemical_list: D002588:Cesium Radioisotopes