PMN adherence to cat ischemic-reperfused mesenteric vascular endothelium under flow: role of P-selectin.

We studied polymorphonuclear leukocyte (PMN) adherence to cat ischemic-reperfused mesenteric artery and vein endothelia under conditions of flow in vitro. Under physiological shear rates, only a few PMNs adhered to non-ischemic-reperfused arterial and venous endothelia (11 +/- 2 and 20 +/- 3 PMN/mm2, respectively). However, after 60 min of ischemia and 20 or 120 min of reperfusion, a significant increase in PMN adherence to arterial endothelium was observed. At 20 min of reperfusion, 44 +/- 4 PMN/mm2 adhered, and at 120 min postreperfusion, 63 +/- 12 PMN/mm2 adhered (P < 0.01 from control). Moreover, a greater degree of PMN adherence occurred on the venous than on the arterial endothelium. Thus, 159 +/- 10 and 198 +/- 12 PMN/mm2 adhered to mesenteric venous endothelium isolated after 20 and 120 min reperfusion, respectively (P < 0.01 vs. arteries). Furthermore, addition of PB 1.3 (20 micrograms/ml), a monoclonal antibody against P-selectin, 5 min before perfusion with PMNs significantly attenuated the increase in PMN adherence to both arterial and venous endothelia (P < 0.01). These results indicate that PMN-endothelial interaction also occurs in conduit vessels after ischemia and reperfusion, although a more profound PMN adherence occurs in veins.