Machine perfusion cuts biological age of donated livers 30% via epigenetic clocks

Researchers at Mass General Brigham applied two classes of aging clocks to 245 liver biopsies. Initial methylation analysis of 37 samples from 19 livers showed perfused organs younger than chronologically younger cold-stored ones. A second cohort of 208 samples from 103 livers measured gene-expression clocks before and after transplant; perfused livers at 34 °C with oxygenated nutrient flow reversed clock readings while cold storage did not.

The 30% age reduction persisted one hour after reperfusion despite universal post-transplant clock acceleration from ischemic stress. This aligns with prior randomized data on normothermic machine perfusion showing 50% lower early allograft dysfunction rates and with Horvath-clock studies linking donor epigenetic age to graft failure. The effect supplies a molecular basis for observed outcome gaps between young and older donors.

Operationally, perfusion extends usable donor pool by converting marginal livers into lower-risk grafts without new pharmacologic agents. Hospitals can now layer clock assays onto existing perfusion circuits to rank organs by predicted longevity rather than discard criteria alone. Next steps include prospective trials linking clock delta to five-year graft survival and integration of perfusion parameters into UNOS allocation scoring.

Further work will test whether targeted perfusion additives can amplify the observed reversal beyond the current 30% threshold.