On the outside, two older mice look the same. But on the inside, one has a liver that looks and functions like a much younger animal.
Cellular biologist Anna Maria Cuervo says just like us, mice accumulate damage to their cells as they grow old.
"When we compare the cells from the young animals to the old animals, we normally find garbage, an accumulation of damage," said Cuervo.
But in a study at Albert Einstein University in New York, Cuervo and her colleagues gave the old mice an extra copy of a gene that helps human cells clean up the damaged proteins she refers to as garbage.
"When we compared this, our animals with a copy of the gene, we found the cells were clean," said Cuervo.
And, she says the genetic tweak not only helped the cell's appearance but the way they performed.
As her team wrote in the journal nature medicine, the livers of the older, modified mice, functioned just as well in tests as animals a quarter of their age.
"By removing the damage inside the cells were able to preserve the function of the whole organ," said Cuervo.
In this study researchers targeted only the liver, but they now plan to see whether the same strategy can also delay age related brain disorders like Alzheimer's.
The researchers are also looking for compounds that can mimic the results of gene therapy, and they're studying how modified diets can help keep organ function high.