ANDREA SEABROOK, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Andrea Seabrook.
People whose hearts are failing have a couple of options. They can get a mechanical device, but artificial hearts don't last forever. They can get a heart transplant, if someone donates an organ in time. Now, someday doctors may be able to offer something else - a real heart grown in a lab. It sounds like science fiction, but one group in Minnesota has figured out a way to grow a heart and make it beat.
NPR's Nell Greenfieldboyce has the story.
NELL GREENFIELDBOYCE: It's no big deal to grow heart cells in a little dish. But take a second and picture your heart beating away in your chest. It's a round meaty muscle the size of your fist with four chambers and a complicated network of blood vessels.
Dr. DORIS TAYLOR (Director of the Center for Cardiovascular Repair, University of Minnesota): The heart is a beautiful, complex organ. And we realized pretty quickly that we weren't going to be able to figure out how to build that in a dish.
GREENFIELDBOYCE: Doris Taylor runs a lab at the University of Minnesota. She says when nature builds a heart, the cells attach to a kind of scaffold or frame made of things like proteins.
Dr. TAYLOR: It's basically what's underneath all of the cells, the tough part that the cells make to hold each other together.
GREENFIELDBOYCE: Taylor and her colleagues thought, okay, what if we took a dead heart and found some way to remove all of the old cell, leaving the scaffold behind? They could then use the scaffold to construct a new heart out of young healthy cells.
Harold Ott worked in Taylor's lab, and he took this on as kind of side project, something to fiddle with. He started treating rat hearts with a bunch of chemicals.
Dr. HAROLD OTT (Massachusetts General Hospital): We had a big chemical shelf in the lab, from A to Z, right? So I started using all sorts of chemicals starting at A and every day perfused a rat heart with some sort of solution.
GREENFIELDBOYCE: He tried enzymes - they dissolved the heart. Other chemicals made the heart swell and change shape. Then, one day, Ott grabbed a chemical known as SDS.
Dr. OTT: It's a regular component of shampoo. It's a soap.
GREENFIELDBOYCE: At first, it seemed like nothing was happening. Then, patches on the heart began to turn white. The red part, the meaty part, was disappearing.
Dr. OTT: You can see the detergent working and making the heart literally translucent. So it turns into a jellyfish sort of appearance. Really, I mean, when you ever saw a jellyfish on the beach, that's exactly how it looks like.
GREENFIELDBOYCE: Except this jellyfish was shaped just like a heart. All of the organ's 3-D structure was still there. Then Ott and his colleagues took heart cells from newborn rats and put them onto the scaffold. The cells stuck, started to grow, and the heart became red again. But it didn't beat until the researchers added a tiny pacemaker. Then the heart began to rhythmically wiggle. After several days, it kept beating even without the pacemaker. Taylor says it was an amazing thing to see.
Dr. TAYLOR: Our reaction was, yes. It was the best we could possibly hope for.
GREENFIELDBOYCE: The heartbeat wasn't that strong, just 2 percent of the pumping action of an adult heart. Still, Taylor thinks they can improve on this work, reported in the journal Nature Medicine. And she's started working with pig hearts, which are about the size of human ones.
Dr. TAYLOR: One possibility is that we could take a pig heart scaffold and then use your cells to repopulate that.
GREENFIELDBOYCE: And since cells are always slowly replacing their scaffold, eventually the heart would be entirely yours.
Taylor says this approach could also work for other organs. Her group has shown that they can get a similar kind of scaffold from the liver, lungs and kidneys.
William Wagner thinks the idea has potential. He's a scientist at the University of Pittsburgh who studies ways of trying to restore heart function.
Dr. WILLIAM WAGNER (Scientist, University of Pittsburgh): This approach does address some of the major challenges that one faces in thinking about how to generate a functional heart that really has the structure and function of the native heart.
GREENFIELDBOYCE: Still, he says, this is just a first step. There's lots of work to do before people could get organs grown in a lab. For example, you'd have to find a human cell that's very good at growing into new heart tissue. That's something that lots of scientists are looking for.
Nell Greenfieldboyce, NPR News.
SEABROOK: Watch scientists make a beating heart. The video is at npr.org.