In a study published this week in the journal ‘Cell’, doctors have shown that a widely prescribed drug used to treat type 2 diabetes can aggressively slow the aging process in worms, by mimicking the effects of caloric restriction.
The drug, Metformin, altered the biochemistry of the worms by affecting a strain of E. coli bacteria that they were bred to carry inside them. This E. coli bacteria is similar to that carried by human beings, and helps the worm extract nutrients from food.
Caloric restriction, or long-term dieting, has been shown in a wide variety of animals to extend lifespan, sometimes by as much as 30%. Drugs that could mimic this effect, without the difficulty and danger of severely restricting food intake, would be a godsend to pharmaceutical companies and dieters alike.
The doctors discovered that the diabetes drug prevented the E. coli from metabolizing B-vitamins and a substance called methionine which is one of the building blocks of proteins. This prevented the worm from absorbing the nutrients that it would normally get from the food and so its body reacted as if it were undergoing caloric restriction.
Overall, treatment with metformin adds up to 6 days of life for the worm which is equivalent to around a third of its normal lifespan. It seems to work by altering metabolism in the bacteria that live in the worm, which in turn limits the nutrients that are available to the worm host and has a similar effect to restricting the diet.
However, in an interesting twist, when the doctors added sugar to the diet of the worms that had been treated with Metformin, the effect disappeared. Since this drug is given to patients with high blood glucose levels, this may be a clue as to how the drug works in human beings.
Of course this is no license for healthy people to go out and begin taking Metformin. Doctors still have no idea if it would have a similar effect on human beings. And just as importantly, it seemingly is rendered useless in the presence of too much sugar. So even if this drug does eventually have medical uses in the treatment of obesity, there will still need to be sacrifices made.
We don’t know from this study whether metformin has any effect on human ageing. The more interesting finding is the suggestion that drugs that alter bacteria in the gut could give us a new way of treating or preventing metabolic diseases like obesity and diabetes.
But having said that, Metformin did extend the worms’ lifespan by a full 30%. If something similar could be done for human beings, it might very well change the way we think about growing old.
Here’s the full article: http://www.wellcome.ac.uk/News/Media-office/Press-releases/2013/WTP052239.htm