WEDNESDAY, June 1, 2022 (HealthDay News) -- No matter how old you are, your liver is always roughly less than three years old, according to a new study.
That's because the liver is constantly renewing itself and replaces its cells equally well in young and old people, the German study explained.
The liver clears toxins from our bodies, putting it at risk of regular injury. To overcome this problem, it has a unique ability to regenerate itself after damage. But it was unclear if the liver's capacity to renew itself diminished with age.
"Some studies pointed to the possibility that liver cells are long-lived while others showed a constant turnover. It was clear to us that if we want to know what happens in humans, we need to find a way to directly assess the age of human liver cells," said researcher Dr. Olaf Bergmann of the Center for Regenerative Therapies Dresden, in Germany.
For the study, Bergmann and his team used a technique called retrospective radiocarbon birth dating to determine the age of livers in a number of people who died between the ages of 20 and 84. In all of them, liver cells were more or less the same age, according to findings published online May 31 in the journal Cell Systems.
"No matter if you are 20 or 84, your liver stays on average just under three years old," Bergmann said.
Not all liver cells are that young, however. A fraction of cells can live up to 10 years before renewing themselves. These cells carry more DNA than typical liver cells and could be protective, the researchers said.
"Most of our cells have two sets of chromosomes, but some cells accumulate more DNA as they age. In the end, such cells can carry four, eight, or even more sets of chromosomes," Bergmann said in a news release from the Technical Institute Dresden.
When his team compared typical liver cells with those richer in DNA, they found fundamental differences in renewal.
"Typical cells renew approximately once a year, while the cells richer in DNA can reside in the liver for up to a decade," Bergmann said.
"As this fraction gradually increases with age, this could be a protective mechanism that safeguards us from accumulating harmful mutations," he added. "We need to find out if there are similar mechanisms in chronic liver disease, which in some cases can turn into cancer."
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SOURCE: Technical Institute Dresden, news release, May 31, 2022