TIME-COURSE OF CORONARY VASCULAR ENDOTHELIAL ADHESION MOLECULE EXPRESSION DURING REPERFUSION OF THE ISCHEMIC FELINE MYOCARDIUM

The time course of endothelial P-selectin, ICAM-1, and E-selectin expr ession was studied in a feline model of myocardial ischemia and reperf usion. Cats were subjected to 90 min of myocardial ischemia followed b y 0, 10, 20, 60, 150, or 270 min of reperfusion. At the end of reperfu sion, the coronary vasculature was examined immunohistochemically to l ocalize monoclonal antibodies (mAbs) PB1.3, RR1/1, and Cy1787 directed against P-selectin, ICAM-1, and E-selectin, respectively. Immunohisto chemical localization for P-selectin, recognized by mAb PB1.3, was max imally expressed 20 min after reperfusion in 60 +/- 6% of coronary ven ules (P < 0.05 compared to non-reperfused controls), and covered 59 +/ - 3% of the endothelial cell perimeter of immunostained coronary venul es. Immunolocalization of mAb PB1.3 gradually declined at 60, 150, and 270 min of reperfusion, Immunohistochemical localization of mAb RR1/1 (anti-ICAM-1) in endothelial cells of coronary venules was observed t o a modest extent in non-ischemic myocardium and at 10, 20, and 60 min of reperfusion, but was significantly increased following 150 and 270 min of reperfusion (P < 0.05 compared non-reperfused controls). At 27 0 min post-reperfusion, mAb RR1/1 was seen in 50 +/- 4% of coronary ve nules. Endothelial immunolocalization of mAb Cy1787 (anti-E-selectin) was only observed in 13 +/- 1 and 14 +/- 3% of coronary venules after 150 and 270 min of reperfusion, respectively, suggesting that pronounc ed expression of E-selectin does not occur within 270 min after reperf usion. These results demonstrate sequential expression of three major endothelial cell adherence molecules in situ following myocardial isch emia and reperfusion. The timing of endothelial cell expressed P-selec tin and ICAM-1. could coordinate neutrophil trafficking during the ear ly stages of reperfusion.