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 fetal 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. (The other two lambs, twins, were born prematurely and did not survive.)
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. Fetal surgery would eliminate these interventions and their resulting problems. "The fetus doesn't need the trachea, so the repair would have time to heal in utero," Fauza explains. "And fetal healing is very good it's better than adult healing."
Fauza, whose research lab works closely with Children's Advanced Fetal Care Center, has been investigating the idea of growing new tissues and organs for these tiny patients for eight years. Since the tissue-engineered grafts are made from the baby's own cells, taken before birth, there would be no risk of the immune system rejecting the tissues, and since fetal cells are immature and not fully specialized, they can be used to generate a variety of tissues.
Currently, most tissue engineers use adult cells to create their lab-grown tissues. While Fauza has also used cells from the ear and from the bone marrow to derive cartilage cells, amniotic fluid is much more readily available. Million
Source:Children's Hospital Boston