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 investigate the effects of leukocyte depletion on functional and endothelial markers of pulmonary performance after cold ischemic injury. METHOD: Groups of 6 rat lungs were flushed with University of Wisconsin solution and then stored at 4 degrees C for 4 hours. They then underwent sanguine 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 per minute per grams of wet lung tissue) by a gravimetric technique. Four groups were studied: group 1 underwent no reperfusion, group 2 underwent 30 minutes of reperfusion, group 3 underwent 30 minutes of leukocyte-deplete reperfusion with an in-line leukocyte filter (PALL), and group 4 underwent 10 minutes of leukocyte-depleting reperfusion followed by 20 minutes of normal 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). Complete leukocyte depletion caused the greatest diminution in the capillary filtration coefficient (0.392 +/- 0.07, P <.001), but initial leukocyte depletion (group 4) also showed a significant diminution (0.74 +/- 0.3, P <.01). 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 myeloperoxidase activity. CONCLUSION: Initial and continued leukocyte depletion are associated with amelioration of reperfusion-induced endothelial injury after cold ischemic injury.