In 2008, scientists in Barcelona announced that they'd transplanted the first tissue-engineered trachea into a 30-year-old woman. The woman, who'd suffered a severe case of tuberculosis, was admitted to the hospital because of shortness of breath that left her unable to care for her children. Doctors decided to replace her trachea with one they grew in the lab using the woman's own stem cells. They used a trachea that had been donated by a man who died of a cerebral hemorrhage. All existing cells were taken off the donor trachea, and then the patient's own stem cells were placed onto it. Because the woman's own stem cells were used, there was a lesser chance that her body would reject the trachea, which is one of the most common reasons for transplant failure. Only four days after the operation to place the new trachea, it was nearly impossible to tell the transplant from the existing lung system. And just two months after the operation, tests of the woman's lung function showed that she was in the normal range for someone her age.