The lungs may repair some of the damage caused by smoking. At least that’s what the researchers say in a new study.
It’s never too late to stop. The most important thing is to quit for good. This conclusion can be drawn from a new scientific study published in the journal Nature on 29 January.
A team of British researchers claims to have observed a strange but very encouraging ability of the lungs to self-heal after smoking cessation.
The researchers sequenced the genomes of about 632 colonies of bronchial epithelial cells (cells covering the bronchi) from 16 individuals.
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Tobacco is known as a mutagen because of the chemicals it contains, causing permanent gene mutations (up to 10,000 per cell) in many lung cells. The study showed that this phenomenon is widespread in the lungs of smokers long before cancer develops. Yet it appears that a small number of cells in the bronchial epithelium remain free of mutations even after many years of smoking, “as if they were staying in a bunker,” the researchers said. And a few years after smoking stopped, these same unmutated cells gradually developed and reproduced, to the point where they replaced the damaged cells, partially “repairing” the damage caused by smoking.
In this sense, smoking cessation contributes to the regeneration of bronchial epithelial cells that have avoided the [mutagenic effect] of tobacco, concluded the researchers.
In particular, the authors report that former smokers have up to 40% of healthy, unmutated cells similar to those found in non-smokers’ bronchial epithelium.
“There is a population of cells that somehow magically repair the lining of the respiratory tract,” said Dr. Peter Campbell, a researcher at the Sanger Institute and the University of Cambridge and co-author of the study for the BBC. “One remarkable thing was to see that patients who stopped smoking, even after 40 years of smoking, had a regeneration of cells that were completely immune to tobacco exposure,” added the scientist.
Although they have not yet assessed how much lung surface area can benefit from this regeneration phenomenon, the researchers believe the study provides additional motivation to stop smoking. The health benefits of smoking cessation have already been demonstrated in the first weeks after the last cigarette, especially in terms of risks to the cardiovascular system.
In 2015, over 158,000 people died from smoking related lung cancer. Quitting smoking lowers the risk of getting lung cancer by up to 50% after 10 years. Consequently it is never too late to quit smoking. Those who are having difficulties giving up tobacco should ask their doctors for help.