Targeting the PDE3B-cAMP-autophagy axis prevents liver injury in long-term supercooling liver preservation

In liver transplantation, donor livers are typically stored in a preservation solution at 4°C for up to 12 hours. However, this short preservation duration can lead to various issues, such as suboptimal donor-recipient matching and limited opportunities for organ sharing. Previous studies have developed a long-term preservation method called supercooling liver preservation (SLP) to address these issues. However, in this study using a rat model, we observed that long-term SLP led to more severe liver damage compared with clinically prevalent traditional static cold storage (SCS) for durations less than 8 hours. To understand the potential mechanism of SLP-induced liver injury, we conducted an integrative metabolomic, transcriptomic, and proteomic analysis. We identified the PDE3B-cAMP-autophagy pathway as a key determinant of SLP-induced liver injury. Specifically, we found that PDE3B was elevated during SLP, which promoted a reduction of cAMP metabolites, triggering an AMPK-dependent autophagy process that led to liver injury in rats. We found that blocking the reduction in cAMP using the PDE3B inhibitor cilostamide inhibited autophagy and substantially ameliorated liver injury during 48-hour SLP in rat livers. Furthermore, we validated the effectiveness of cilostamide treatment in preventing liver injury in pig and human liver 48-hour SLP models. In summary, our results reveal that metabolic reprogramming involving the PDE3B-cAMP-autophagy axis is the key determinant of liver injury in long-term SLP and provide an early therapeutic strategy to prevent liver injury in this setting.