Expression of adhesion molecules on circulating PMN during hyperdynamic endotoxemia.
In a porcine model of hyperdynamic endotoxemia, we studied the numerical expression of L-selectin and beta 2-integrins on circulating polymorphonuclear leukocytes (PMN). Functional changes of beta 2-integrins were determined by the adhesion of PMN to C3-coated zymosan particles. Anesthesized pigs received a continuous infusion of Salmonella abortus-equi endotoxin (5 micrograms.kg body wt-1.h-1) for 270 min (endotoxin group; n = 7). A control group received 0.9% NaCl (n = 6). L-selectin had decreased 30 min after the induction of endotoxemia [59.1 +/- 11.9 vs. 91.6 +/- 15.5 relative fluorescence units (RFU) at baseline; P < 0.05], reaching minimal values after 150 min (23.9 +/- 3.9 RFU in endotoxin group vs. 95.2 +/- 30.4 RFU in control group; P < 0.05). PMN adhesion to C3-coated zymosan increased at 30 min (41.3 +/- 9.9% in endotoxin group vs. 2.4 +/- 1.1% in control group; P < 0.05) and remained significantly elevated thereafter. In contrast to the rapid shedding of L-selectin and functional upregulation of beta 2-integrins, the numerical expression of beta 2-integrins remained unchanged until 60 min (44.8 +/- 2.8 vs. 32.2 +/- 1.7 RFU at baseline; P < 0.05); compared with the control group, significantly elevated values were observed 150 min after the start of endotoxin (48.9 +/- 2.4 RFU in endotoxin group vs. 36.5 +/- 2.7 RFU in control group; P < 0.05). We conclude that numerical and functional expressions of beta 2-integrins are dissociated during endotoxemia. Although upregulation of beta 2-integrins might render PMN more adhesive to the vascular endothelium, the presence of activated PMN in the circulation suggests that low expression of L-selectin might impede adhesion.
Holzer
K
K
Institute for Surgical Research, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany.
Thiel
M
M
Moritz
S
S
Kreimeier
U
U
Messmer
K
K
D000818:Animals; D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D003176:Complement C3 / Q000378:metabolism; D019446:Endotoxemia / Q000378:metabolism* / Q000503:physiopathology; D004731:Endotoxins / Q000633:toxicity; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D016023:Integrins / Q000096:biosynthesis; D007958:Leukocyte Count; D018375:Neutrophil Activation / Q000502:physiology; D009504:Neutrophils / Q000378:metabolism*; D011485:Protein Binding; D012475:Salmonella; D019087:Selectins / Q000096:biosynthesis; D013552:Swine; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D015854:Up-Regulation / Q000502:physiology; D015054:Zymosan / Q000494:pharmacology
D015815:Cell Adhesion Molecules; D003176:Complement C3; D004731:Endotoxins; D016023:Integrins; D019087:Selectins; D014409:Tumor Necrosis Factor-alpha; D015054:Zymosan