Endothelial P-selectin expression contributes to the first wave of neutrophil (polymorphonuclear leukocyte; PMN) inf lux in several inf lammatory conditions. Although remote tissue ischemia, such as a crush injury to the hindlimb, may result in P-selectin-mediated pulmonary leukosequestration, it is not known whether the lungs exhibit a similar response after hypothermic preservation or when subjected to a direct ischemic insult. To determine if P-selectin may mediate early primary graft failure, left lungs harvested from male Lewis rats were preserved for 6 hr at 4؇C and transplanted orthotopically into isogeneic recipients. Recipients immunodepleted of PMNs before transplantation demonstrated improved graft function; pulmonary vascular resistance was reduced Ϸ6-fold, arterial oxygenation was increased Ϸ3-fold, and recipient survival was increased Ϸ4-fold (P < 0.05, 0.05, and 0.005, respectively). Administration of a blocking anti-P-selectin IgG 10 min before reperfusion diminished graft PMN infiltration and resulted in improved graft function and recipient survival compared with controls. To establish the role of P-selectin in normothermic pulmonary ischemia, mice were subjected to temporary left pulmonary artery ligation. After functional removal of the nonischemic right lung, mice deletionally mutant for the P-selectin gene (Pselectin ؊͞؊) exhibited reduced PMN infiltration (Ϸ2-fold), improved arterial oxygenation (Ϸ2-fold), and improved survival (Ϸ3-fold) compared with P-selectin ؉͞؉ control mice (P < 0.05, 0.01, and 0.05, respectively). These studies isolate and identify the central role of a single gene product (Pselectin) in early PMN recruitment and tissue injury after frank pulmonary ischemia and in the setting of lung transplantation after hypothermic preservation.

Abstract-Transiently increased expression of leukocyte adhesion receptors after lung preservation contributes to early graft demise by recruiting leukocytes, activating complement, and causing microcirculatory stasis. We hypothesized that inhibiting intercellular adhesion molecule-1 (ICAM-1) expression even briefly may significantly improve lung graft function and that the preservation period might provide a unique window to deliver a therapeutic pulse of antisense oligonucleotide ICAM-1 to inhibit ICAM-1 expression after transplantation. Interleukin-1␤-treated rat pulmonary endothelial cells given a 20-mer phosphorothioate oligonucleotide comprising an antisense span targeted to the 3Ј-untranslated region of rat ICAM-1 demonstrated an oligonucleotide dose-dependent reduction in ICAM-1 expression. Using a cationic liposomal carrier, this same antisense oligonucleotide (but not the sense control) instilled into the pulmonary vasculature at the time of preservation reduced subsequent graft ICAM-1 expression and graft leukostasis and markedly improved oxygenation, pulmonary blood flow, and graft survival. These experiments demonstrate that the preservation period presents a window during which to target an anti-ICAM-1 expression strategy to inhibit early adhesion receptor expression and improve functional outcome after lung transplantation. (Circ Res. 2000;86:166-174.)Key Words: intercellular adhesion molecule-1 Ⅲ lung transplantation Ⅲ isograft Ⅲ leukocyte adhesion receptor C linical lung transplantation at its best is a harrowing experience, because lung grafts can fail catastrophically shortly after reperfusion for reasons that are often not understood. 1,2 Clinical lung preservation strategies are directed toward maintaining proper electrolyte and osmotic homeostasis, but surprisingly little is done to protect the vast pulmonary vascular network on which the lung depends for both integrity and function. Because the early expression of the leukocyte adhesion receptor P-selectin can result in rapid sequestration of neutrophils (polymorphonuclear leukocytes [PMNs]) after lung transplantation, 3 promoting microcirculatory stasis and local tissue destruction, we hypothesized that a strategy that protects the lungs from early leukocyte recruitment could confer clinical benefit. Because P-selectin places neutrophils into a favorable steric relationship for intercellular adhesion molecule-1 (ICAM-1) binding to ␤ 2 -integrins, we hypothesized that early inhibition of inducible ICAM-1 expression might serve as a useful target for therapeutic intervention in lung transplantation to prevent acute graft injury. Toward this end, we have focused on the unique opportunity provided by the lung harvest procedure, during which it is possible to deliver agents (such as antisense oligodeoxynucleotides) ex vivo directly into the vasculature, which can block adhesion receptor expression during the first few critical hours after reperfusion. The current studies were designed to (1) elucidate the nature and functional relevance of endo...

Background-Lung preservation disrupts normal vascular homeostasis, resulting in increased permeability, vasoconstriction, and endothelial cell adhesion for neutrophils. We hypothesized that a storage strategy that best preserves post-lung transplantation (LTX) vascular homeostasis might be organ and species specific. Because of the potential utility of a rat LTX model for developing improved lung preservation strategies, we have attempted to identify the optimal physical conditions for rat lung graft storage. Methods and Results-Conditions that were tested included harvest inflation pressure (0, 10, or 20 mm Hg), inflation gas composition (100% N 2 , room air, or 100% O 2 ), and storage temperature (4°, 10°, or 15°C). Modified Euro-Collins solution served as the base preservation solution for all experiments, with a preservation duration of 4 to 6 hours. Arterial oxygenation (PaO 2 , mm Hg), pulmonary vascular resistance (mm Hg/mL per minute), recipient survival (%), and graft neutrophil infiltration (⌬Abs 460 nm /min) were measured 30 minutes after transplantation of the left lung and exclusion of the right lung from the circulation. All tested conditions significantly affect post-LTX vascular homeostasis. Inflation at 10 mm Hg pressure preserved lungs significantly better than did other pressures. There was a tendency for room air to improve all measured variables compared with 100% N 2 or 100% O 2 and a significant improvement in recipient survival with room air storage. Of the 3 storage temperatures investigated, 10°C storage provided the best preservation in terms of PaO 2 , graft neutrophil infiltration, and survival. Conclusions-We conclude that storage at 10°C, 10 mm Hg inflation pressure, with room air establishes optimal lung storage conditions with Euro-Collins solution in this rat LTX model. These data suggest that these conditions should be used to evaluate new and potentially improved preservation strategies.

Background: Primary lung graft failure is common, and current lung preservation strategies are suboptimal. Because the decline in lung levels of cyclic adenosine monophosphate and cyclic guanosine monophosphate during preservation could enhance adhesiveness of endothelial cells for leukocytes as well as increase vascular permeability and vasoconstriction, we hypothesized that buttressing these levels by means of a preservation solution would significantly improve lung preservation. Methods: An orthotopic rat left lung transplantation model was used. Lungs were harvested from male Lewis rats and preserved for 6 hours at 4°C with (1) Euro-Collins solution (n = 8); (2) University of Wisconsin solution (n = 8); (3) low-potassium dextran glucose solution (n = 8); (4) Columbia University solution (n = 8), which contains a cyclic adenosine monophosphate analog (dibutyryl cyclic adenosine monophosphate) and a nitric oxide donor (nitroglycerin) to buttress cyclic guanosine monophosphate levels; or (5) Columbia University solution without cyclic adenosine monophosphate or nitroglycerin (n = 8). PaO 2 , pulmonary vascular resistance, and recipient survival were evaluated 30 minutes after left lung transplantation and removal of the nontransplanted right lung from the pulmonary circulation. Results:

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