Smokers could turn back the clock on the damage caused by their habit thanks to their lungs’ almost “magical” ability to heal themselves, newly published research suggest.
The study, outlined in a paper in the journal Nature, found that when smokers quit, healthy cells emerge to replace the tobacco-damaged ones.
This process has “been seen even in patients who had smoked a pack a day for 40 years before giving up”, the BBC reports.
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Exactly what did the study find?
The UK team behind the research analysed lung biopsies from 16 people, “including a mix of current smokers, ex-smokers, adults who had never smoked and children, looking for the mutations that can lead to cancer”, says The Guardian.
They found that nine in every ten lung cells in the smokers had mutations, including those that can cause cancer. But in the ex-smokers, up to 40% of the cells were healthy ones that were comparable to those of people that had never smoked.
The study’s joint senior author, Peter Campbell of the UK-based Wellcome Sanger Institute, said that the damaged cells had not been able to “magically repair themselves”.
“Rather, they are replaced by healthy cells that have escaped the damage from cigarette smoke,” he explained.
The “precise mechanism by which that replacement occurs is not yet clear”, says The Guardian, but the scientists believe there may be a sort of reservoir of cells upon which the body can draw.
How these cells avoid the genetic devastation caused by smoking is also a mystery as yet, but the team said they appeared to “exist in a nuclear bunker”, adds the BBC.
And the reaction?
The findings have been welcomed by anti-smoking campaigners, as an added incentive for smokers to quit.
Speaking to the BBC, Dr Rachel Orritt, from Cancer Research UK, said: “It’s a really motivating idea that people who stop smoking might reap the benefits twice over - by preventing more tobacco-related damage to lung cells, and by giving their lungs the chance to balance out some of the existing damage with healthier cells.”
Study author Campbell said: “People who have smoked heavily for 30, 40 or more years often say to me that it’s too late to stop smoking – the damage is already done.
“What is so exciting about our study is that it shows that it’s never too late to quit.”
However, some experts have sounded a note of caution about the cell replacement theory. Gerd Pfeifer, professor at the Michigan-based Van Andel Institute’s Center for Epigenetics, told The Guardian that the sample size in the new study was too small to make sweeping conclusions.
But the research “raises many interesting questions worthy of further investigation”, he added.
According to the BBC, around 47,000 cases of lung cancer are recorded each year in the UK alone, almost three-quarters of which are caused by smoking.
