A drug called metformin is used to treat type 2 diabetes.
However, researchers at UT Southwestern Medical Center have found metformin may also protect against radiation exposure.
Principal investigator Dr. Jerry Shay, a professor of cell biology, told KERA’s Sam Baker that NASA has been searching for just such a drug.
They've been seriously looking for ways to protect our astronauts that might go to the moon for a long time, or go all the way to Mars and back. The amount of radiation they will receive from space will be so high that right now, NASA is trying to figure out if they can do this without some sort of protection.
Why metformin?
Part of how metformin works is what we call an antioxidant. When you expose a person to radiation, you generate elements called reactive oxygen species. And those can then cause damage to DNA, which could lead to an increased risk for things like cancer. And so, we reasoned that if metformin acted as an antioxidant and it reduced these reactive oxygen species, it might be the perfect countermeasure that NASA had been working for.
How did you test to find this out?
We started with in vitro. We took normal human cells and exposed them to radiation with or without being treated with metformin. And this was all in a culture dish. And we found that the amount of damage was repaired much quicker in the cells that were pretreated with that form.
The surprising finding was to pre-treat mice with metformin, just for 2 or 3 days. Then we exposed mice to what is considered a lethal dose of radiation pretreated with metformin. We saw a huge overall survival in mice.
So, it really proved beyond a shadow of a doubt, at least in mice, that this could protect patients or astronauts against the side effects of radiation.
Are there limits on how and when you could use metformin for this purpose?
We did experiments to test that, and we can show even within an hour of taking this that we get some protection. If we give it a day or so before, we get more protection.
So again, this is the concept that if you know, you're going to be exposed to radiation, such as a first responder to a nuclear accident, or to an astronaut going into space, or even a patient who has to undergo radiation therapy for their cancer. This has the potential to be a game changer for that.
So, now the question becomes, should this go into clinical development to give patients when they're getting the radiation therapy? And this is something just radiation oncologists at UT Southwestern are very interested in.
But I can't help but think people listening to this might think "I've been on metformin for some time now. Does that mean in addition to what it's doing for my diabetes, does this mean that I've been building up protection against radiation exposure the whole time?"
I think the answer to your question is yes. People who have been on metformin long term probably have much better radiation protection, just because they've been on it a long time.
Let me make sure that people listening to this don't think, oh gee, I got to get metformin and start on this. This is a prescription medication. It's not something you get over the counter. And doctors will not prescribe it to you just so you think I want to live longer, I want to have a lower risk of cancer and things like that. At this point, it's not approved for that.
It's only approved for patients with, basically, late-onset diabetes. So, I think that while it's exciting, it's going to take time and clinical trials to be sure this is something that may be more applicable. So I think this is the number one reason why basic research like the type we do, is so important.
RESOURCES:
Radioprotective effect of the anti-diabetic drug metformin
Diabetes drug metformin may protect against radiation exposure
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