Scientists have implanted a laboratory-made windpipe into a toddler who was born without one, the latest advance in the quest to grow viable human organs in the lab.

While surgeons have performed several windpipe transplants in adults, this is the first time it has been attempted in a child, a scenario that presents many challenges. The surgery is technically complex, and the organ must function even as the child grows rapidly. The patient must gradually learn how to swallow, taste and speak, things she has never done before.

"It will be a new world for her," said Paolo Macchiarini of Karolinska University Hospital in Sweden, a lead surgeon involved in the nine-hour operation.


The patient's new windpipe, or trachea, was made from a special plastic material and her own cells. This means patient the won't have to take powerful drugs to prevent her immune system from rejecting the organ. But the two-year-old girl is expected to outgrow the windpipe in four or five years, at which point she will need a new, larger one, said Dr. Macchiarini.

The quest to engineer body parts has made big strides in recent years as scientists have attempted to grow more and more complex organs. A London researcher who has transplanted lab-made tear ducts and an artery into patients is now building a nose for another patient. A Madrid lab is trying to grow a human heart.

The latest operation was done April 9 on Hannah Warren at the Children's Hospital of Illinois. Hannah was born in Seoul with a rare condition called tracheal agenesis, or the lack of a trachea. No child with the ailment has lived past 6. Until now, Hannah could only breathe via a tube inserted into her esophagus that connected to her lungs.

The new windpipe was designed and fabricated from the same type of plastic that is used to make soft-drink and water bottles. It was seeded with stem cells obtained from Hannah's bone marrow. When transplanted into Hannah, the stem cells automatically picked up the body's signals and got transformed into epithelial cells, the kind found in any trachea.

That was a surprise. In the past, scientists thought they had to change the stem cells into epithelial cells before they put the transplant in. But the latest procedure, done under the approval of the U.S. Food and Drug Administration, shows that the body can trigger the transformation on its own.

"If the body knows how to do this for the trachea, maybe it knows how to do this for other organs, too," said David Green, president of Harvard Bioscience Inc., of Holliston, Mass., which built the lab-made windpipe. He said the next step is to attempt controlled trials in a larger number of patients who need trachea transplants.

Write to Gautam Naik at