美国国家公共电台 NPR A Gulp Of Genetically Modified Bacteria Might Someday Treat A Range Of Illnesses（在线收听）

STEVE INSKEEP, HOST:

It may be time to update what we know about bacteria. Needless to say, an infection by the wrong kind of bacteria can make you ill. We also learn about good bacteria, which play a healthy role in our digestive systems. Now think of genetically engineered bacteria. Scientists believe they can send these bacteria through your body to treat medical problems. Here's NPR health correspondent Rob Stein.

ROB STEIN, BYLINE: Jonah Reeder is starting his day at his home in Farmington, Utah. But instead of eating a normal breakfast, Reeder, who's 21, is getting ready to gulp down a special protein shake.

JONAH REEDER: The nutrients in it like to sit at the bottom, so I usually have to shake it up.

STEIN: This isn't just any protein shake. Reeder was born with a rare genetic disorder known as phenylketonuria, or PKU. If he eats meat, drinks milk or consumes most other common proteins, toxic levels of a chemical called phenylalanine builds up in his body and could damage his brain.

REEDER: So it doesn't have phenylalanine, which my body can't have. So it's basically protein, except without phenylalanine, you know.

STEIN: Later this morning, Reeder is checking into a clinic in Salt Lake City. He's volunteering for a study testing an experimental treatment for his disease. The treatment's a genetically modified bacteria, modified to essentially do what Reeder's body can't - get rid of phenylalanine.

REEDER: I'm excited. I'm really excited to help out and hopefully find a treatment for PKU.

STEIN: And so...

REEDER: Bye, Mom.

UNIDENTIFIED PERSON: Bye.

STEIN: Reeder heads off to the clinic in Salt Lake City to start the study. The bacteria Reeder is helping test is a form of E. coli. Some types of E. coli make people really sick. But Caroline Kurtz, a scientist at a company called Synlogic, says this E. coli lives in our guts.

CAROLINE KURTZ: It is a naturally occurring probiotic bacteria. But we can enhance its function by introducing genes, by changing genes that are there and design the cells to either produce something or consume something that may be beneficial for a patient.

STEIN: Like chew up phenylalanine - Synlogic has also engineered E. coli to fight other diseases - for example, to get rid of life-threatening levels of ammonia that build up in the bodies of people with cirrhosis of the liver.

KURTZ: This is a living medicine that can respond to its environment.

STEIN: Synlogic's modified microbes are part of a whole new field of medical research that emerged from two of the hottest realms of biomedical science - our microbiomes, the friendly microbes that inhabit our bodies, and synthetic biology, the power to genetically engineer all kinds of life, including bacteria in our guts. Pam Silver is a synthetic biologist at Harvard.

PAM SILVER: It's an exciting new world of being able to use synthetic biology to program microbes to treat diseases, which, I believe, is the future.

STEIN: Scientists hope to genetically modify our microbes to treat a long list of diseases; things like ulcerative colitis and inflammatory bowel disease.

SILVER: Microbes are something that we, as synthetic biologists, see as highly engineerable. We understand how to engineer microbes well, so it seems like the perfect interface between a synthetic biology and health.

STEIN: One company is already testing genetically modified microbes to heal mouth sores from cancer chemotherapy. Another just started trying to treat Type 1 diabetes. For his part, Reeder admits he was a little nervous at first.

REEDER: When you hear about E. coli, you think sickness, like throwing up. So I was a little bit skeptical. I wasn't sure what to think because I was going to be ingesting E. coli.

STEIN: But the more he learned, the more excited Reeder got about trying some of these engineered microbes.

REEDER: I think that's very cool that they found a way to use sort of a natural probiotic that's found in the digestive tract to help the human body, you know?

STEIN: Reeder doesn't know if he ended up getting the genetically modified microbes or placebo, but he thinks he got the microbes.

REEDER: I could immediately feel my cognitive abilities slowing down after drinking the 20 grams of protein. And then I took the drug, and I started feeling a lot better. I obtained more energy, and my cognitive abilities got quicker. It was really cool to feel that. I could tell it was working. It was pretty cool.

STEIN: Now, a lot more research is needed to know whether genetically engineered microbes are safe and might really work. But Synlogic hopes to report results from the cirrhosis and PKU studies later this year. Rob Stein, NPR News.