Mathilde Fontez, editor-in-chief of the scientific magazine Epsiloon looks back on a recent discovery. Researchers have succeeded for the first time in measuring the age of our liver.
franceinfo: And what researchers are seeing is that this vital organ regenerates so quickly that we all have livers that are less than three years old!
Mathilde Fontez: Yes. Only 3 years old. We knew that the liver regenerates. But not to this extent! Until now, precise measurements had only been made on mice, and it was difficult to extrapolate the results to humans. But that’s it, researchers at the University of Dresden, Germany, have measured the speed of the process: The cells of our liver are renewed throughout life, with a rate of 20% per year, and therefore a average age of 2.5 years.
Overall, our liver produces around 175 million new cells every day. In other words, more than half of all your liver cells are born in that year.
How did they go about measuring this?
By a roundabout way: they used nuclear testing. We know that each test releases a particular form of carbon atom, carbon 14, into the atmosphere. We also know when the tests took place. And we know precisely the carbon-14 concentration curve in the atmosphere: it decreases over the years after a test.
However, it is from this carbon that our body manufactures its new cells. Measuring the level of carbon 14 in liver cells therefore makes it possible to determine their date of birth, and to show that our liver has frenetic activity.
Does that mean our liver isn’t aging?
Actually no. But this measurement of regeneration makes it possible to specify its aging process. This is a big issue: remember that the liver performs more than 300 different functions: the purification of waste, the synthesis of carbohydrates, lipids, the storage of vitamins. And this organ is subject to cancer: there are more than 8000 cases per year, in France, mainly men.
However, this study details aging: it shows that cell regeneration deteriorates over time: in a 25-year-old human, 90% of liver cells are less than two years old. Whereas at 75, it drops to 75%. The researchers are continuing to work to understand this cellular dynamic and thereby try to better identify the dysfunctions of this vital organ.