New Trachea Engineered from Amniotic Fluid Cells

Cartilage tube made from mesen-
chymal stem cells; © Dario Fauza

The tracheal repair technique is one of several tissue-engineering approaches pioneered at Children’s Hospital Boston that use the foetus’s own cells, drawn from the amniotic fluid that surrounds it, to create patches to fix birth defects - in this case, before birth.

Paediatric surgeon Dario Fauza’s team multiplied the amniotic mesenchymal cells in culture, then “seeded” them onto biodegradable tubes of the needed dimensions and shape. The tubes and cells were then exposed to growth factors that caused the mesenchymal cells to differentiate into cartilage cells. When the engineered grafts were ready, they were used to reconstruct defective tracheas in seven foetal lambs. Four to five weeks later, the lambs were born, and all five lambs that survived to term were able to breathe spontaneously at birth, four of them with no sign of respiratory distress.

While many congenital defects can be safely repaired after birth, Fauza’s goal is to fix tracheal defects in utero. Once the baby is born, tracheal surgery requires that the baby be intubated and ventilated long after the operation while the trachea heals; this can lead to many complications, including failure of the repair. Foetal surgery would eliminate these interventions and their resulting problems. “The foetus doesn’t need the trachea, so the repair would have time to heal in utero,” Fauza explains. “And foetal healing is good, better than adult healing.”

Less than two tablespoons of amniotic fluid provide enough foetal cells to repair a malformation in utero or after birth – potentially, even years later, Fauza says. He envisions a future in which amniotic fluid is banked for everyone’s use. “Foetal cells are the best cells you can have for tissue engineering,” he says. “They grow very well and you can coach them to do what you want.”; Source: Children's Hospital Boston