IL-1β in bronchial lavage fluid is a non-invasive marker that predicts the viability of the pulmonary graft from the non-heart-beating donor

Abstract

Background Viability testing of the pulmonary graft retrieved from the non-heart-beating donor (NHBD) is mandatory for successful outcome after lung transplantation. Functional assessment by ex vivo reperfusion, however, remains a cumbersome procedure. In this study, therefore, we wanted to investigate the possible value of the proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) measured in bronchial lavage fluid (BLF) in predicting functional outcome of the pulmonary graft after reperfusion. Methods Domestic pigs (29.9 ± 0.56 kg) were sacrificed and divided in 5 groups ( n = 5/group). In the non-ischemic group (NHBD-0), the heart-lung block was explanted immediately. In the other groups the animals were left untouched with increasing time intervals (1 hour = NHBD-1; 2 hours = NHBD-2; 3 hours = NHBD-3). Thereafter both lungs were cooled topically via chest drains up to a total ischemic interval of 4 hours. Finally, in the heart-beating donor group lungs were flushed and stored for 4 hours (4°C) [HBD]. BLF samples were taken from the right lung in all groups after explantation for measurement of IL-1β and TNF-α and the left lung was prepared for evaluation in an isolated reperfusion circuit. Haemodynamic, aerodynamic and oxygenation parameters were measured. Wet-to-dry weight ratio (W/D) was calculated after reperfusion. Results Graft function deteriorated with increasing time intervals after death. A strong correlation was found between the increase of IL-1β concentration measured in BLF and the increase in pulmonary vascular resistance (r = 0.80), mean airway pressure (r = 0.74) and wet-to dry weight ratio (r = 0.78); ( p < 0.0001, for all parameters). No significant differences in TNF-α levels in BLF were observed amongst groups ( p = 0.933). Conclusions IL-1β in BLF prior to reperfusion correlated well with graft function and may therefore be a useful, non-invasive marker that can predict the viability of the pulmonary graft from the NHBD.