Modelling the effects of IL-1β –mediated inflammation during ex vivolung perfusion

Abstract

Ex vivo lung perfusion (EVLP) provides a potential means of increasing the number of donor-lungs suitable for transplantation. The concentration of IL-1β during EVLP has been previously identified as being predictive of 1-year transplant survival. We sought to develop a model of lung reperfusion to assess the impact of IL-1β on neutrophil adhesion and physiological function during EVLP. Methods An ex vivo model for assessing neutrophil adhesion was developed with lung pairs and then applied to a split lung model of perfusion, whereby lung pairs (N=4) were dissected into individual lungs and perfused simultaneously, with one receiving a bolus of exogenous IL-1β. Perfusates were collected at regular time points and measured for a markers of endothelial dysfunction well as being used in a variety of functional in vitro assays. Tissues were assessed for differences in transcriptomic profile via Nanostring. Results Labelled neutrophils were successfully identified in both perfusate and tissue biopsies from lungs perfused using a split-lung model. Lungs treated with IL-1β had significantly lower levels of circulating neutrophils in perfusate at regular time points and at the end of EVLP (p = 0.042), exhibited greater oedema formation (p = 0.065) and increased pCO2/lactate. Perfusates from lungs treated with IL-1β facilitated greater E-selectin expression and neutrophil adhesion in vitro. Reduction in adhesion marker expression (p = 0.067) and neutrophil adhesion (p = 0.025) occurred when perfusates were pre-incubated with an IL-1β neutralizing antibody (NAb). Tissues from IL-1βstimulated lungs had an enhanced inflammatory RNA profile. Discussion These data suggest that blockade of IL-1β during EVLP could produce a less inflammatory microenvironment via decreasing endothelial activation and neutrophil adhesion, increasing the number of lungs available for transplant whilst improving post-transplant outcomes.