Alcohol can cause permanent DNA damage to stem cells
Drinking alcohol can cause permanent DNA damage to the reserve pool of stem cells in the body, which was proved by the recent study that show’s the link between drinking and cancer. The research was carried out using genetically modified mice, provides the most compelling evidence that alcohol causes cancer by damaging the DNA in cells, eventually leading to deadly mutations.
“How exactly alcohol causes damage to us is controversial,” said Prof Ketan Patel, who led the work at the MRC Laboratory of Molecular Biology in Cambridge. “This paper provides very strong evidence that an alcohol metabolite causes DNA damage [including] to the all-important stem cells that go on to make tissues.”
This was based on the earlier study that shows Acetaldehyde which is a breakdown product of alcohol acts as toxin and damages the DNA. The latest work showed that acetaldehyde destruct DNA, causing permanent damage if the effects of the toxin are not neutralized by two natural defence mechanisms. The first defence mechanism clears away the acetaldehyde and the second repairs the DNA damage.
By genetically “knocking out” these two layers of defence, scientists were able to show DNA damage accumulating until cells eventually stopped working entirely.
The study showed that DNA damage was exacerbated when mice lacked the first of defence mechanism -The enzyme called Aldehyde dehydrogenase 2 (ALDH2), which helps prevent potentially poisonous build-ups of acetaldehyde.
Around 8% of the World’s Population, mostly of East Asian ancestry, has an inherited deficiency of ALDH2 (sometimes known as the flushing mutation), that could make clear the high prevalence of oesophageal cancer in countries such as China.
In mice that lacked both natural defences against alcoholic beverages, their ability to create fresh blood vessels was completely ruined after being given diluted liquor for ten days and nights, the analysis found. Sequencing the genome of the stem skin cells demonstrated that their DNA had been scrambled to the point that the cells no longer functioned.
“Our study highlights that not being able to process alcohol effectively can lead to an even higher risk of alcohol-related DNA damage and therefore certain cancers,” said Patel. “But it’s important to remember that alcohol clearance and DNA repair systems are not perfect and alcohol can still cause cancer in different ways, even in people whose defence mechanisms are intact.”
Alcohol consumption causes around 4% of cancers in the UK, or around 12,800 cases each year. Just one pint of lager or a large glass of wine a day significantly increases the risk of mouth, throat, oesophageal, breast and bowel cancers. But there is no evidence that drinkers are at a substantially increased risk of blood cancers, say experts, despite the new findings showing that drinking can alter the DNA in blood stem cells.
“Actually the blood system has a very stringent quality control mechanism to get rid of anything that is damaged,” said Patel, adding that this might explain why alcoholics tend to become severely anaemic. It is possible that the body’s defence mechanisms against acetaldehyde are weaker in other tissues.
Prof Magdalena Zernicka-Goetz, a stem cell biologist at the University of Cambridge, said the findings were very important: “This is beautiful work which puts our finger on the molecular basis for the link between alcohol and increased cancer risk and stem cells,” she said.
“This thought-provoking research highlights the damage alcohol can do to our cells, costing some people more than just a hangover, Prof Linda Bauld, an expert on cancer prevention at Cancer Research UK, which partly funded the research, said.
“We know that alcohol contributes to over 12,000 cancer cases in the UK each year, so it’s a good idea to think about cutting down on the amount you drink”, she added.
Source- The Guardian