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Tissue engineering can successfully
reconstruct defective tracheas in fetal lambs, according to
researchers at Children's Hospital Boston. Tracheal defects
are rare but life threatening, and babies born with
incomplete, malformed or missing tracheas cannot breathe and
must immediately go on heart-lung bypass. According to lead
researcher once a baby is born with a tracheal defect, he must
be incubated and ventilated long after his surgical operation,
potentially leading to complications. Amniotic fluid is easily
collected during pregnancy and contains unspecialized cells,
making many of the tissues needed to perform repairs, lead
researcher says. His team took this idea and multiplied the
amniotic mesenchymal cells in culture, then seeded them into
biodegradable tubes. The tubes and cells were exposed to
growth factors, causing the 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, all five of the remaining
lambs were born, four with no sign of respiratory distress.
(Two of the lambs, twins, were born prematurely and did not
survive.) "The fetus doesn't need the trachea, so the repair
would have time to heal in the uterus," lead researcher says.
"And fetal healing is very good -- it's better than adult
healing." Less than two tablespoons of amniotic fluid would
provide enough fetal cells to repair a malformation in the
uterus or after birth, according to lead researcher. Also,
because the tissue-engineered grafts are made from the baby's
own cells, there would be no risk of the immune system
rejecting the tissues. |