Reduction of endothelial injury after hypothermic lung preservation by initial leukocyte-depleted reperfusion

Objectives: Leukocyte depletion has been shown to ameliorate the effects of reperfusion injury in many organ systems. The aim of this study was to inv estigate the effects of leukocyte depletion on functional and endothelial m arkers of pulmonary performance after cold ischemic injury. Method: Groups of 6 rat lungs were flushed with University of Wisconsin sol ution and then stored at 4 degrees C for 4 hours. They then underwent sangu ine reperfusion for 30 minutes, during which time functional measures (gas exchange, pulmonary artery, and airway pressures) were made and after which the lungs underwent estimation of endothelial permeability by measurement of the capillary filtration coefficient (in grams per centimeter of water p er minute per grams of wet lung tissue) by a gravimetric technique. Four gr oups were studied: group 1 underwent no reperfusion, group 2 underwent 30 m inutes of reperfusion, group 3 underwent 30 minutes of leukocyte-deplete re perfusion with an in-line leukocyte filter (PALL), and group 4 underwent 10 minutes of leukocyte-depleting reperfusion followed by 20 minutes of norma l reperfusion. Results: The capillary filtration coefficient increased between group 1 and group 2 animals (1.05 +/- 0.32 to 3.07 +/- 0.47 [mean +/- SEM]; P <.01). C omplete leukocyte depletion caused the greatest diminution in the capillary filtration coefficient (0.392 +/- 0.07, P <.001), but initial leukocyte de pletion (group 4) also showed a significant diminution (0.74 +/- 0.3, P <.0 1). Complete or initial leukocyte depletion caused no significant change in functional measures of pulmonary performance. Complete leukocyte depletion produced less pulmonary leukostasis, as assessed by means of myeloperoxida se activity. Conclusion: Initial and continued leukocyte depletion are associated with a melioration of reperfusion-induced endothelial injury after cold ischemic i njury.