A British boy who became the first child in the world to receive a windpipe transplant lined with his own stem cells is doing well and has gone back to school.
Ciaran Finn-Lynch underwent the ground-breaking transplant at Great Ormond Street Hospital (GOSH), London in March 2010.
In a world first, surgeons removed the boy's trachea and replaced it with a donor windpipe laced with Ciaran’s own stem cells, to prevent the transplant being rejected by the immune system.
Now 13, Ciaran is able to breathe normally, has grown 11 cm taller and does not require any anti-rejection drugs, according to a paper published online in the Lancet journal.
Ciaran was born with a condition known as long segment tracheal stenosis, which left him with a very narrow windpipe and severe breathing problems.
He spent the first four months of his life in hospital after undergoing major surgery to reconstruct his airways at just six days old. Metal tubes called stents were used to hold his airways open, but in 2009, a stent eroded causing severe bleeding.
In 2010, doctors decided a tracheal transplant was Ciaran's only option.
They stripped a donor trachea of all its living cells, so they were left with a tracheal scaffold of inert collagen which was transplanted into Ciaran. Surgeons then sprayed the newly transplanted windpipe with stem cells which had been taken from Ciaran's bone marrow.
Cells from Ciaran's damaged trachea were also applied to the new windpipe during surgery to kick-start the growth of a new windpipe lining. After the operation, cellular growth factors - cytokines - were used to stimulate the growth and differentiation of the graft cells.
The procedure was the first of its kind to grow stem cells within the body of a child, rather than in a laboratory.
In another world first, the surgeons used a biodegradable stent to keep the airways open for the first six months after the operation while the windpipe grew back.
Martin Elliott, director of the national service for severe tracheal disease in children at GOSH, said: "The ideal outcomes for tracheal transplants in children are normal airway and lung function, good general growth, a decent quality of life, and no further surgical interventions.
So far we have achieved this, but we are at the edge of medicine and, similarly to first attempts of organ transplantation in the 1950s, many challenges remain."
Study co-author Martin Birchall, a professor of laryngology, at University College London's Ear Institute, said: "Since the treatment plan for Ciaran was devised in an emergency, we used a novel mix of techniques that have proved successful in treating other conditions.
"To minimise delays, we bypassed the usual process of growing cells in the laboratory over a period of weeks, and instead opted to grow the cells inside the body, in a similar manner to treatments currently being trialled with patients who have had heart attacks.
"We need more research on stem cells grown deliberately inside the body, rather than grown first in a laboratory over a long time.
"This research should help to convert one-off successes such as this into more widely available clinical treatments for thousands of children with severe tracheal problems worldwide."