Stem cells used to rebuild boy's windpipe

If successful, they believe it could lead to a revolution in

regenerative medicine.

The operation, lasting nearly nine hours, took place at London's Great Ormond Street children's hospital on Monday.

Stem cells taken from the boy's bone marrow were injected into a donor trachea, or windpipe. The organ, which had first been stripped of its own cells, was then implanted into the boy.

Over the next month doctors expect the stem cells to begin transforming themselves within the boy's body into internal and external tracheal cells.

The boy, whose identity is being kept secret, is said to be doing well and breathing normally.