Modeling the Effects of IL-1-mediated Inflammation During Ex Vivo Lung Perfusion Using a Split Human Donor Model

Background. The association between interleukin-1 beta (IL-1 beta) concentrations during ex vivo lung perfusion (EVLP) with donor organ quality and post-lung transplant outcome has been demonstrated in several studies. The mechanism underlying IL-1 beta-mediated donor lung injury was investigated using a paired single-lung EVLP model. Methods. Human lung pairs were dissected into individual lungs and perfused on identical separate EVLP circuits, with one lung from each pair receiving a bolus of IL-1 beta. Fluorescently labeled human neutrophils isolated from a healthy volunteer were infused into both circuits and quantified in perfusate at regular timepoints. Perfusates and tissues were subsequently analyzed, with perfusates also used in functional assays. Results. Neutrophil numbers were significantly lower in perfusate samples collected from the IL-1 beta-stimulated lungs consistent with increased neutrophil adhesion (P = 0.042). Stimulated lungs gained significantly more weight than controls (P = 0.046), which correlated with soluble intercellular adhesion molecule-1 (R-2 = 0.71, P = 0.0043) and von-Willebrand factor (R-2 = 0.39, P = 0.040) in perfusate. RNA expression patterns for inflammatory genes were differentially regulated via IL-1 beta. Blockade of IL-1 beta significantly reduced neutrophil adhesion in vitro (P = 0.025). Conclusion. These data illustrate the proinflammatory functions of IL-1 beta in the context of EVLP, suggesting this pathway may be susceptible to therapeutic modulation before transplantation.