The Children's Hospital waived the cost, which was likely in the hundreds of thousands of dollars, as part of their mission as a Roman Catholic hospital and as a way to highlight stem cell therapy that doesn't involve human embryos, Dr. Mark Holterman of the Children's Hospital of Illinois told the AP.
So far, doctors say the stem cell-generated windpipe appears to be working. Hannah is still on a ventilator but her doctors say she will eventually be able to live at home and lead a normal life. Since the windpipe is made from Hannah's own cells, there's no need to suppress her immune system to avoid rejection, as during organ transplants.
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"We feel like she's reborn," Hannah's father, Darryl Warren, told the Associated Press.
Regenerative medicine is still in the very early stages, but doctors won approval from the Food and Drug Administration to go ahead with the procedure since Hannah had been expected to die before reaching age 6.
The Italian doctor, Paolo Macchiarini, had worked on 14 previous surgeries where patients' own stem cells were used to create new windpipes. Doctors predict Hannah will need a new windpipe in about five years to accommodate her growing body.