title: PMNs primed for superoxide release and increased CD11b expression do not sequester in normal lung.
abstract: Our previous work has implicated platelet activating factor (PAF)-induced neutrophil (PMN) priming and increased CD11b/CD18 receptor expression in the pathogenesis of lung injury following gut ischemia/reperfusion (I/R). In this model CD11b blockade abrogates lung injury but does not alter PMN priming or pulmonary leukosequestration. We, therefore, hypothesized that PAF-stimulated PMN priming and CD11b expression are insufficient to promote lung PMN sequestration. Normal rat PMNs, labeled with 51Cr, were incubated with PAF (10 ng/ml) to induce priming for superoxide (O2-) generation and enhance CD11b expression. Gut I/R animals underwent superior mesenteric artery occlusion for 45 min. 51Cr-labeled PMNs (2 x 10(7)) were injected iv. Study groups, consisting of (a) normal/control, (b) sham/laparotomy, and (c) gut I/R, were given either normal or PAF-treated PMNs. PAF-primed PMNs had increased 2- release and CD11b expression, but did not sequester in the lungs of normal rats. However, following gut I/R PAF-treated PMNs sequestered in the pulmonary bed. These data suggest that PAF priming for O2- generation and increased CD11b expression are insufficient alone to promote PMN sequestration in the lung. Rather, additional factors generated by gut I/R are necessary for this process.
authors.affiliation: Department of Surgery, Denver General Hospital, Colorado 80204-45007, USA.
authors.forename: B
authors.initials: B
authors.lastname: Fontes
authors.forename: E E
authors.initials: EE
authors.lastname: Moore
authors.forename: F A
authors.initials: FA
authors.lastname: Moore
authors.forename: K
authors.initials: K
authors.lastname: Koike
authors.forename: V
authors.initials: V
authors.lastname: Carl
authors.forename: A
authors.initials: A
authors.lastname: Banerjee
mesh_terms: D000818:Animals; D018845:CD11 Antigens / Q000032:analysis*; D008168:Lung / Q000166:cytology* / Q000502:physiology; D008297:Male; D009504:Neutrophils / Q000276:immunology / Q000502:physiology*; D010972:Platelet Activating Factor / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013481:Superoxides / Q000378:metabolism*
chemical_list: D018845:CD11 Antigens; D010972:Platelet Activating Factor; D013481:Superoxides