Senolytic treatment preserves biliary regenerative capacity lost through cellular senescence during cold storage

Abstract Liver transplantation is the only curative option for patients with end-stage liver disease. Despite improvements in surgical techniques, non-anastomotic strictures (characterised by the progressive loss of biliary tract architecture) continue to occur after liver transplantation, negatively impacting liver function and frequently leading to graft loss and re-transplantation. To study the biological effects of organ preservation before liver transplantation, we generated murine models that recapitulate liver procurement and static cold storage.
In these models, we explored the response of cholangiocytes and hepatocytes to cold storage, focusing on responses that affect liver regeneration, including DNA damage, apoptosis and cellular senescence. We show that biliary senescence is induced during organ retrieval and exacerbated during static cold storage, resulting in impaired biliary regeneration. We identified Decoy Receptor 2 (DCR2)-dependent responses in cholangiocytes and hepatocytes, which differentially affect the outcome of those populations during cold storage Moreover, in vitro knockdown of DCR2 via CRISPR, increased cholangiocyte proliferation and decreased cellular senescence whilst having the opposite effect in hepatocytes. Using the p21KO model to inhibit senescence onset, we showed that biliary tract architecture was better preserved during cold storage. Similar results were achieved by administering senolytic ABT737 to mice before procurement.Finally, we perfused senolytics into discarded human donor livers and showed that biliary architecture and regenerative capacities are better preserved. Our results indicate that cholangiocytes are susceptible to senescence and identify the use of senolytics and the combination of senotherapies and machine-perfusion preservation to prevent this phenotype and reduce the incidence of biliary injury post-transplantation.