Machine Perfusion Makes Donated Livers Biologically Younger, Study Finds

Once a donor organ leaves the body, it starts to degrade. Surgeons preserve donated livers with a preservative solution and ice, leaving only hours to transplant them. A growing alternative for less healthy organs is machine perfusion: pumping in nutrients and removing waste for six to 12 hours, letting doctors assess it; studies suggest it improves outcomes.

Research shared with MIT Technology Review, led by surgeons Heidi Yeh and Alban Longchamp of Mass General Brigham with Jesse Poganik, an aging researcher at Brigham and Women's Hospital, found perfused livers appear biologically younger at a molecular level. The team used "aging clocks" to measure biological age rather than calendar age. A clock reading epigenetic patterns (chemical marks on DNA) in 37 samples from 19 livers showed perfused livers had a lower biological age than younger ice-stored livers.

In a larger analysis of 208 samples from 103 livers, the team used gene-activity clocks, biopsying livers after up to six hours in cold storage or perfusion, and often an hour post-transplant. Perfused livers were younger. "Pumping them at 34 degrees with oxygen and nutrients actually reversed the biological age," Longchamp said. Adjusted for age, Poganik put the gap at about 30 percent. Biological age rose in all livers after transplant, likely from procedural stress, but perfused organs stayed younger.

Nathanael Raschzok, a Charité Universitätsmedizin Berlin surgeon not involved, called the work impressive, though its meaning for recipients remains unclear. Donors studied were in their 30s to 50s; hospitals sometimes use donors aged 70 to 85. Perfusion is costly: about €10,000 per organ in Germany, Raschzok says, and $80,000 to $100,000 in the United States, according to Yeh.

Researchers saw changes in cell pathways linked to inflammation and tissue structure, plus more activity in a pathway that removes and recycles damaged cell parts. Poganik hopes to develop a biological-age test for transplant suitability; his team is testing drugs to lower it further.