Antidepressant Extends Life of Worms An antidepressant used in humans can extend the life span of tiny worms by about 30 percent, according to a new finding that has intrigued scientists who study aging.
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Antidepressant Extends Life of Worms

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Antidepressant Extends Life of Worms

Antidepressant Extends Life of Worms

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MICHELE NORRIS, host:

Most people would love to have a long and happy life. Well, a new study has found that a certain drug can extend lifespan by about 30 percent, at least the lifespan of tiny worms. There's no word on whether the worms are happy in their old age, but the drug that makes them live longer is an antidepressant that's used in people.

Here's NPR's Nell Greenfieldboyce.

NELL GREENFIELDBOYCE: In Linda Buck's lab, researchers spend a lot of time looking at really tiny worms. They're called C. elegans. Scientists like them because they share a lot of important biology with other animals including humans, even though Buck says they look pretty humble.

Dr. LINDA BUCK (Associate Director of Basic Sciences, Fred Hutchinson Cancer Research Center): They're little worms. They look like little squiggles. They live in the soil normally.

GREENFIELDBOYCE: And they normally live for just a couple of weeks. Buck wanted to see if she could find some chemical that could make the worms live longer. So her lab at the Fred Hutchinson Cancer Research Center in Seattle just went out and bought a huge random assortment.

Dr. BUCK: The hundred thousand in chemicals that we bought were just diverse chemicals that were collected from many sources by a chemical company. And we didn't even know what they were when we were testing them.

GREENFIELDBOYCE: They ended up testing over 80,000 chemicals. Each one was put into a little container of liquid that was home to about a dozen worms. Researchers then kept watch.

Dr. BUCK: They shake them up and they shine some light on them and - so they look for movement. And that's how they decide whether they're alive or not.

GREENFIELDBOYCE: In the journal Nature, the scientists report that over a hundred chemicals increased the worms' lifespan - sometimes by a lot. And one of those chemicals turns out to be very similar to a drug already used in humans. An antidepressant called mianserin.

Now if you take antidepressants, don't get all excited. This drug is not one of those popular SSRIs like Prozac. In fact, Buck's lab tested several of those drugs and did not see any effect. And before you ran out and ask your doctors to switch you to mianserin, Buck has this word of caution.

Dr. BUCK: I would not suggest that the drug has similar effects in human. Look at the how the opposite effect for all we know. I think it'll be a long time before anyone can determine what the effects on humans might be.

GREENFIELDBOYCE: Her lab wants to start by seeing if the drug will also extend the life of mammals like mice. And she wants to figure out how the drug has its effect on worms. There are some hints that the drug may be affecting brain chemistry in a way that makes the worms feel like they're starving. That's important because scientists have known for a long time that worms that really are starved live longer.

Caloric restriction also extends life in other animals. So it's of great interest to scientists like Leonard Guarente, a biologist at MIT. He says many researchers have been studying specific genes involved in caloric restriction. But he appreciates that Buck has taken a totally different approach.

Dr. LEONARD GUARENTE (Biologist, Massachusetts Institute of Technology): The fact that they screened through this large chemical library is a kind of tour de force. And the fact that they converged on something and then it's something surprising is really quite striking.

GREENFIELDBOYCE: He says it's too soon to know what the finding means. But he says studies like this one are helping make the idea of a life-extending pill seem less and less far out.

Nell Greenfieldboyce, NPR News.

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