In vivo adenovirus-mediated endothelial nitric oxide synthase gene transfer ameliorates lung allograft ischemia-reperfusion injury

Objective: Nitric oxide regulates vascular tone, inhibits platelet aggregat ion, and inhibits leukocyte adhesion, all of which are important modulators of ischemia-reperfusion injury. This study aimed to determine the effects of endothelial constitutive nitric oxide synthase gene transfer on ischemia -reperfusion injury in a rat lung transplant model. Methods: In group I, do nor animals were injected intravenously with 5 x 10(9) pfu of adenovirus-en coding endothelial constitutive nitric oxide synthase, Groups II and III se rved as controls, whereby donor animals were injected with either 5 x 10(9) pfu of adenovirus encoding beta-galactosidase or saline solution, respecti vely. Twenty-four hours after injection, left lungs were harvested and pres erved for 18 hours at 4 degrees C, then implanted into isogeneic recipients , which were put to death 24 hours later. Recombinant endothelial constitut ive nitric oxide synthase gene expression was evaluated by Western blotting and immunohistochemistry. Lung grafts were assessed by measuring arterial oxygenation, myeloperoxidase activity, and wet/dry weight ratios, Results: Western blotting confirmed the overexpression of endothelial constitutive n itric oxide synthase in lungs so transfected compared with controls. Twenty -four hours after reperfusion, mean arterial oxygenation was significantly improved in group I compared with group IX and III controls (189.4 +/- 47.1 mm Hg vs 71.7 +/- 8.9 mm Hg and 67.8 +/- 12.2 mm Hg, P = .02, P = .01, res pectively). Myeloperoxidase activity, a reflection of tissue neutrophil seq uestration, was also significantly reduced in group I compared with groups II and III (0.136 +/- 0.038 Delta OD/mg/min vs 0.587 +/- 0.077 and 0.489 +/ - 0.126 Delta OD/mg/min, P = .001, P = .01, respectively). Conclusion: Aden ovirus-mediated gene transfer with endothelial constitutive nitric oxide sy nthase ameliorates ischemia-reperfusion injury as manifested by significant ly improved oxygenation and decreased neutrophil sequestration in transplan ted lung isografts, Endothelial constitutive nitric oxide synthase gene tra nsfer may reduce acute lung dysfunction after lung transplantation.