Your liver is just under three years old — even if you’re 80 — because cells in the organ are constantly renewing themselves, study finds
- German scientists have created the livers of 30 people aged 20 to 84
- Their study is the first time cells in this organ have been aged by scientists
- Bodies replace about one percent of their cells every day, some of which, like those in the gut, live for less than a week, while brain cells can live for years
Livers are never older than three years — even when one reaches 80 — because the cells are constantly renewing themselves, a study has revealed.
German scientists said their study would help improve understanding of age-related diseases in the organ, such as fatty liver and cirrhosis.
It’s the first time the cells in this organ — which is the only thing that can regenerate itself when damaged — have been aged by scientists.
Human bodies replace billions of cells every day, with those lining the gut having the shortest lifespan of just four days. But others, such as those in muscle, can live for 70 years, while those in the brain can survive as long as a person lives.
Cells in the liver last about three years before being replaced, scientists say. Pictured above is the organ (red area) along with the gallbladder (yellow), which stores bile
In the study, – published earlier this week in the journal cell systems — researchers from the Technical University of Dresden, 100 miles from Berlin, studied liver samples from 32 patients between 20 and 84 years old.
They had 32 samples from autopsies of deceased patients, 12 from biopsies and nine from one type of cell from the liver.
To age the sample, the researchers used a method based on measuring the amount of carbon in cells from the atmosphere.
What is the liver?
The liver is the largest internal organ of the human body and weighs about 1.4 kg.
It is the main powerhouse with over 500 functions including producing bile, storing iron and vitamins.
It also cleanses the body of drugs, alcohol and old blood cells.
The organ consists of about 75,000 hexagonal lobes, each made of millions of liver cells.
Every two minutes, all the blood in the body passes through these lobes.
Unlike other organs like the heart and lungs, the liver is the only one that can regenerate itself — even when up to 90 percent is damaged.
Regular consumption of more than 30 units (15 pints of beer, five bottles of wine) per week can cause chronic liver cirrhosis (damage).
Carbon is absorbed into plants through photosynthesis and then enters humans when they eat vegetables.
There were huge – though not dangerous – amounts of carbon in the environment in the 1950s thanks to the above-ground testing of atomic bombs, which showed up in cells.
But after these were banned, levels gradually began to drop.
It was this drop that the scientists used to estimate the age of cells.
The study found that liver cells live on average for about a year, and never more than three years.
But up to 20 percent — scientifically called diploid hepatocytes because they contain extra genes — had a lifespan of up to ten years.
These cells were more common in older patients, suggesting the scientists may play a role in ensuring the organ continues to replenish itself.
dr. Olaf Bergmann, the geneticist who led the study, said, “It doesn’t matter if you’re 20 or 84, your liver stays on average just under three years old.”
He added: ‘It is important to establish these features of cell turnover in the adult liver, especially to gain a better understanding of age-related diseases and liver cancer.’
Despite the ability to regenerate, there is mounting evidence that livers still age overtime due to mutations in cell genes.
This can lead to problems with normal cell function causing low-level inflammation in the organ, a risk factor for several diseases, reports a 2019 study in Computational and Structural Biotechnology†
The human body replaces about 330 billion cells every day — or one percent of the total, according to a 2016 study in PLOS Biology†
It also revealed that while some cells tend to live for only a few days, others last a lifetime.
The shortest-lived cell is thought to be the sperm cell, which, on average, is kept for only three days before being replaced.