A new study published in Nature brings sorrow to all alcohol consumers, be they light or heavy users. An older study showed a significant link between cancer and light drinking, but researchers haven’t quite established a causation between the two. Now, Ketan J. Patel, a Cambridge geneticist, and his team discovered that an alcohol metabolite — acetaldehyde — causes significant DNA damage in the blood stem cells of mice.
After drinking alcohol, the body converts it into smaller parts, one of them being acetaldehyde, a toxic compound. When the body is over-flushed with acetaldehyde, the molecule accumulates within the cells and starts to cause DNA and chromosomal damage.
Researchers from the Medical Research Council’s lab of molecular biology at Cambridge University genetically engineered mice by deleting the genes that controlled the formation of acetaldehyde dehydrogenase 2 (ADLH2). Acetaldehyde dehydrogenases are a group of enzymes that are one of the natural mechanisms of alcohol degradation. Their purpose is to convert acetaldehyde into acetic acid. Basically, they rendered the mice unable to produce ADLH2.
Next, they gave the mice diluted ethanol and then analyzed their genome to see what had happened. They discovered that acetaldehyde had altered their DNA by causing double-stranded breaks, which can lead to cancer.
Scientists were amazed when they saw that mice lacking the ALDH2 enzyme had four times the DNA damage in their blood stem cells when compared with mice that possessed the enzyme.
“We saw huge amounts of DNA damage in these cells. Bits of DNA were deleted, bits were broken and we even saw parts of chromosomes being moved about and rearranged,” Patel, the lead author said.
Another part of the experiment was to establish the methods through which the body repairs the damage done by acetaldehyde. Patel’s team learned that cells have a coordinated way of dealing with acetaldehyde poisoning.
“There are lots of ways cells can fix DNA damage,” says Patel in a press release. “What we’ve shown is that when damage happens as a result of breaking down alcohol, there’s a hierarchy when selecting the best way to carry out repairs.”
The most frequently chosen way was the Fanconi anemia repair pathway — a rare genetic disease resulting in impaired response to DNA damage. Other methods used were the non-homologous end-joining repair pathway and the homologous recombination pathway.
Either way, the news is not that great for drinkers. Of course, it would be best if all mankind could renounce drinking alcohol once and for all, but let’s face it: that’s not happening any time soon.
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