Present state of nonheart-beating lung donation

Ex Vivo Perfusion With Adenosine A2A Receptor Agonist Enhances Rehabilitation of Murine Donor Lungs After Circulatory Death

BACKGROUND

Ex vivo lung perfusion (EVLP) enables assessment and rehabilitation of marginal donor lungs before transplantation. We previously demonstrated that adenosine A2A receptor (A2AR) agonism attenuates lung ischemia-reperfusion injury. The current study utilizes a novel murine EVLP model to test the hypothesis that A2AR agonist enhances EVLP-mediated rehabilitation of donation after circulatory death (DCD) lungs.

METHODS

Mice underwent euthanasia and 60 minutes warm ischemia, and lungs were flushed with Perfadex and underwent cold static preservation (CSP, 60 minutes). Three groups were studied: no EVLP (CSP), EVLP with Steen solution for 60 minutes (EVLP), and EVLP with Steen solution supplemented with ATL1223, a selective A2AR agonist (EVLP + ATL1223). Lung function, wet/dry weight, cytokines and neutrophil numbers were measured. Microarrays were performed using the Affymetrix GeneChip Mouse Genome 430A 2.0 Array.

RESULTS

Ex vivo lung perfusion significantly improved lung function versus CSP, which was further, significantly improved by EVLP + ATL1223. Lung edema, cytokines, and neutrophil counts were reduced after EVLP and further, significantly reduced after EVLP + ATL1223. Gene array analysis revealed differential expression of 1594 genes after EVLP, which comprise canonical pathways involved in inflammation and innate immunity including IL-1, IL-8, IL-6, and IL-17 signaling. Several pathways were uniquely regulated by EVLP + ATL1223 including the downregulation of genes involved in IL-1 signaling, such as ADCY9, ECSIT, IRAK1, MAPK12, and TOLLIP.

CONCLUSIONS

Ex vivo lung perfusion modulates proinflammatory genes and reduces pulmonary dysfunction, edema, and inflammation in DCD lungs, which are further reduced by A2AR agonism. This murine EVLP model provides a novel platform to study rehabilitative mechanisms of DCD lungs.

The contribution of airway and lung tissue ischemia to primary graft dysfunction

PURPOSE OF REVIEW

Primary graft dysfunction (PGD) is the primary obstacle to short-term survival for post-lung transplant patients. PGD is a form of acute lung injury secondary to donor brain death and ischemia-reperfusion damage to the allograft affecting 10-25% of all lung transplant recipients. This article reviews the significant role of allograft ischemia in the phenotypic presentation of PGD and the evidence for activation and disruption of normal cellular pathways for the development and long-term sequelae.

RECENT FINDINGS

Pathways implicated in the pathogenesis of PGD resultant from tissue ischemia include abnormalities in coagulation and fibrinolysis, epithelial cell injury, endothelial cell dysfunction, chemotaxis, and alterations in cell adhesion. Blood and bronchoalveolar lavage fluid biomarkers from these pathways have been increasingly identified as useful for diagnosing and predicting the development of severe PGD.

SUMMARY

Future efforts at preventing and treating severe PGD should focus on techniques for altering the pathways involved in PGD pathogenesis. Ex-vivo lung perfusion and transduction with interleukin-10 are promising modalities for preventing PGD and expanding the available lung transplant donor pool.