Boy’s windpipe is rebuilt using his own stem cells
Doctors have rebuilt the windpipe of a 10-year-old British boy from his own stem cells.
If successful, they believe it could lead to a revolution in regenerative medicine.
The operation, lasting nearly nine hours, took place at Great Ormond Street children's hospital on Monday.
Stem cells taken from the boy's bone marrow were injected into the fibrous collagen "scaffold" of 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 in 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.
There is no danger of the new cells triggering an immune response because they are derived from his own tissue. With a normal transplant, rejection of the organ would necessitate dampening down the child's immune system with suppressive drugs.
The procedure was a big step forward from the pioneering surgery conducted in Spain two years ago on 30-year-old mother Claudia Castillo, the first person to receive a transplant organ created from stem cells.
She was given a section of tracheal airway rebuilt from stem cells but using a much more complex and costly process. Doctors grew the new tissue outside the body by rotating the donor graft in a special "bioreactor" before transplanting it into the patient's body.
But the British boy's body acted as a living "bioreactor". The windpipe was treated with a carefully mixed cocktail of chemicals designed to trigger signals that would allow the tissue to grow in situ.
Professor Martin Birchall, head of translational regenerative medicine at University College London, said: "This procedure is different in a number of ways, and we believe it's a real milestone.
"It is the first time a child has received stem cell organ treatment, and it's the longest airway that has ever been replaced. I think the technique will allow not just highly specialised hospitals to carry out stem cell organ transplants.
"Now we need to conduct more clinical trials to demonstrate that this concept works. We'd like to move to other organs as well, particularly the larynx and oesophagus. Importantly, we need to think about how to make regenerative medicine a key part of our health care."
Preparation of the donor organ was carried out in at Great Ormond Street by stem cell pioneer Professor Paolo Macchiarini, from Careggi University Hospital in Florence. He led the Italian, British and Spanish team behind Ms Castillo's transplant.
Last year he carried out the "living bioreactor" stem cell procedure for the first time on a 53-year-old Italian woman, replacing part of her windpipe. The successful operation proved that the concept worked.
Professor Macchiarini was contacted by British doctors after they ran out of options for helping the boy, who was born with a condition called long segment tracheal stenosis.
At birth he had a windpipe measuring only one millimetre across and was unable to breathe.
Attempts were made to patch up his trachea and hold it open with supporting "stents". But eventually they eroded, damaging the aorta, the main artery taking blood out of the heart.
