Scientists at Monash University in Australia have identified a protein that drives age-related damage in vital organs, opening a potential new avenue for treatments that could help people stay healthier as they get older.
The research, published in the journal Immunity, discovered a link between the protein Granzyme K and signs of ageing in the heart, liver and kidneys. Granzyme K is a protein produced by immune cells, and its levels are known to increase significantly with age in both mice and humans, but its precise role in age-related organ damage had remained unclear until now.
Senior researcher Professor Nicole La Gruta, from the Monash Biomedicine Discovery Institute, said the findings could provide a new way to protect vital organs from damage as they age. "What we've discovered is that Granzyme K plays an important role in driving some of that damage," she said.
The study used preclinical mouse models, comparing older mice that did not have the protein Granzyme K with those that did. In mice lacking Granzyme K, researchers observed significantly improved heart function and reduced fibrosis, a form of scarring that can affect how well an organ works. The mice also showed reduced signs of age-related damage in their liver and kidneys.
What made the result particularly striking, the researchers said, was that the mice without the protein showed reduced signs of organ ageing even though their immune systems continued to age normally. That suggests Granzyme K is not simply a marker of ageing but an active driver of the damage that ageing brings to organs.
The team then examined human datasets and found elevated levels of Granzyme K in patients with several inflammatory and fibrotic diseases, including lupus nephritis, a kidney disease, and heart failure. The pattern in people matched what the researchers had seen in the mice, strengthening the case that the protein matters in human ageing too.
The researchers are now investigating ways to selectively block Granzyme K, to determine whether targeting the protein later in life could provide similar protection. The hope is that a treatment which dampens the protein's activity could slow the scarring and decline that makes organs fail in old age.
Professor La Gruta cautioned, however, that further research is needed to determine whether the same benefits could be achieved in humans. The work so far is preclinical, and any treatment based on it would have to go through years of testing for safety and effectiveness before it could reach patients.
The discovery adds to a growing picture of ageing as a process driven in part by the immune system itself. As people grow older, immune cells change in ways that can quietly damage the tissues around them, and Granzyme K now looks like one of the molecules carrying out that damage.
If the findings hold up in further studies, they could eventually lead to therapies aimed not at a single disease but at the shared process of organ ageing itself — protecting the heart, liver and kidneys together, and helping people spend more of their later years in good health rather than living with failing organs.
