Bar-Ilan study turns back signs of ageing in the livers of old mice

Scientists at Bar-Ilan University reported in May 2026 that some of the molecular damage of ageing in the liver can be partly reversed, at least in mice. The study, published in Nature Communications, came from the laboratory of Prof. Haim Cohen, who directs the university's Sagol Healthy Human Longevity Center, and was led by doctoral students Ron Nagar and Zacharia Schwartz, with collaborators at the US National Institutes of Health.

The work focused on chromatin, the combination of DNA and proteins that decides which genes are switched on. In old mouse livers the team found that chromatin gradually loosens in places that should stay tightly closed. As a result, inflammatory genes that ought to be silent become active, while genes needed for normal liver function fade.

The researchers raised the activity of SIRT6, a protein Cohen's group has studied for years and previously linked to longer lifespan in mice, in animals that were already about 24 months old, roughly the equivalent of people in their seventies or eighties. Within about a month the chromatin in their liver cells had shifted back toward the pattern seen in young animals. Inflammation fell and metabolic activity improved, and the effect was still present three months later. The team also identified a chemical tag on chromatin that marks this age-related loosening and that SIRT6 removes, which could serve as a way to measure biological ageing in tissue.

The authors stress the limits of the work. Only male mice and only the liver were studied, and the animals were engineered or treated with a viral vector rather than a drug. An Israeli company, SirTLab, is developing compounds that act on SIRT6 and is seeking funding for human trials. Even so, the study is described as the first to show SIRT6 restoring youthful patterns in animals that were already old, rather than merely slowing decline.