A porcine model to study ex vivo reconditioning of injured donor lungs.

Background: Brain death rapidly results in lung injury making many cadaveric donors unsuitable for lung transplantation. The aim of this study was to develop a porcine model of lung injury as a first step to study mechanisms to ameliorate the pretransplant graft quality during ex vivo perfusion.

Materials And Methods: Male pigs (47 ± 8 kg) were divided into three groups: LPS-group [LPS] (n = 6) [instillation of lipopolysaccharides (15 mg/lung)]; saline-group [SAL] (n = 5) (50 mL saline/lung); and sham-group [SHAM] (n = 5). CT scans of the lungs were taken 17h before (T-17) and 31h after (T31) instillation. Broncho-alveolar lavage (BAL) was performed, and blood gases, hemodynamic, and aerodynamic parameters were measured at T 0 and T 50. Blood samples and temperature were taken at all time points. Pigs were sacrificed during cold pulmoplegia (T 50), and tissue samples were collected for histology. Wet lung weight was measured.

Results: Wet lung weight/body weight was higher in [LPS] versus [SAL] (P < 0.05). Total BAL cells were higher in [LPS] versus [SAL] and [SHAM] at T 50 (left: P < 0.001 and P < 0.01; right: P < 0.01 and P < 0.001). More neutrophils were present in BAL of [LPS] at T 50 versus T 0 (left: P < 0.001; right: P < 0.01). [LPS] demonstrated more ground glass opacities (GGO) on CT at T 31 compared with [SAL] and [SHAM] (P < 0.05). Histologically, more interstitial hemorrhage was observed in [LPS] versus [SAL] and [SHAM](P < 0.01). Neutrophils in blood increased and lymphocytes decreased in [LPS] versus [SAL] (P < 0.05). No differences were observed in hemodynamic and aerodynamic parameters and in saturation between groups at T 50.

Conclusions: LPS instillation caused inflammation with more cells in BAL, changes on CT, and histology. However, no physiologic changes occurred.