Lung neutrophil retention and injury after intestinal ischemia/reperfusion
Objective: To define the mechanisms responsible for the lung leukosequestration and injury elicited by intestinal ischemia/reperfusion (I/R). Methods: The effect of 120 minutes of superior mesenteric artery occlusion and 90 minutes of reperfusion on neutrophil deformability, lung neutrophil retention, and pulmonary microvascular permeability was. determined. Results: Compared with control surgery, intestinal I/R resulted in a significant increase in neutrophil stiffness (mean yield pressure [Pyield], 1.533 ± 0.075 and 2.302 ± 0.288 cm H2O, respectively) and lung neutrophil content (6.3 ± 1.4 and 31.5 ± 6.4 U/g wet weight, respectively). These changes were not affected by inhibition of neutrophil adherence before gut reperfusion. However, the increased lung microvascular permeability elicited by gut I/R (0.111 ± 0.020 [control surgery] and 0.255 ± 0.041 [I/R] mL/min/cin H2O/100 g lung tissue) was significantly attenuated by administration of antibodies directed against neutrophil or endothelial determinants of leukocyte adhesion. Conclusions: The results of this study suggest that intestinal I/R is a potent inflammatory stimulus that elicits an increase in neutrophil stiffness and lung neutrophil retention independent of neutrophil-endothelial cell adhesion. In contrast, the increased lung microvascular permeability elicited by gut I/R is attenuated by strategies that interfere with neutrophil-endothelial cell adhesion.