Cell type- and time-dependent biological responses in ex vivo perfused lung grafts

Ex vivo lung perfusion (EVLP) is a largely employed technique in transplantation that permits the reassessment of marginal lungs, thereby increasing the graft pool. However its biological effects on the different lung cell types are not known. In order to advance our mechanistic understanding and further improve EVLP, we conducted a pioneer study involving single-cell RNA-seq (scRNA-seq) on two human lungs declined for transplantation. We integrated data sets generated at 4 h (clinical duration) and 10 h (prolonged duration) and revealed functional changes common to both lungs that include inflammation in most cell types, loss of barrier function in epithelial and endothelial cells especially at 10 h, and reduction of migration properties in immune cells. In addition to providing insights into the biological effects of EVLP, scRNA-seq applied to EVLP offers a highly powerful way to evaluate novel EVLP therapeutic advances that will benefit to lung transplantation. Donor lungs used in this study were from donation after brain death and were determined to be unsuitable for transplantation. Donor lung retrieval was carried out according to current clinical practice. After transportation at 4°C, lungs were processed to EVLP. Lung biopsies were taken just before EVLP (0 h), after 4 and 10 h EVLP, and analyzed using scRNAseq. ***Raw data for human samples not available due to patient privacy concerns***