Porcine model of sepsis-induced systemic inflammation and acute lung injury in donor lungs
Abstract Background: The shortage of organ donors is a major challenge in lung transplantation. To expand the lung donor pool, ex-vivo lung perfusion (EVLP) has emerged as a platform for assessment and reconditioning marginal donor lungs. In this study a stable and reproducible large animal model of lipopolysaccharide (LPS) induced systemic inflammation and acute lung injury (ALI) was developed.Methods: Pigs (n=6) were anesthetized and monitored. After infusion of LPS (20 μg/kg) for 1 hour, followed by a 90-minute response period, lungs were procured and kept on ice for 2 hours, followed by 4 hours of EVLP. Pulmonary function, inflammatory biomarkers and edema formation were measured in vivo before procurement and during EVLP. Pro and anti-inflammatory cytokines were assayed in blood and in EVLP perfusate, which were collected before and every 30 minutes after LPS administration and EVLP.Results: LPS infusion resulted in significant hemodynamic instability, characterized by marked pulmonary hypertension, decreased systemic blood pressure and increased heart rate. This was associated with increased levels of TNFα, IL-10, IL-6, but no change in IL-1β. Ex vivo assessment of injured lungs showed graft dysfunction characterized by impaired gas exchange and edema formation. The inflammatory profile showed stable but elevated TNFα levels, and continuous production of interleukins during EVLP.Conclusion: We describe a reproducible large animal model of LPS-induced systemic inflammation and ALI. EVLP alone was unable to recondition severely injured lungs. These findings suggest that the EVLP platform requires adjuncts such as targeted anti-inflammatory agents to allow reconditioning of marginal donor lungs.