Stem Cell-Engineered Windpipe for Cancer Patients
While Transplants Successful, Many Experts Say Technique Not Yet a Proven Therapy
By LARA SALAHI
Aug. 2, 2010
Doctors regenerated tissue from the patients' nose and bone marrow stem cells to create tracheas biologically identical to the patients' original organs. Both patients underwent the transplant in early July and were released from the hospital just weeks after the surgery, according to the Associated Press.
One of the patients was able to speak again only a few days after the surgery, said Dr. Paolo Macchiarini, professor of surgery at the University of Barcelona in Spain and the head surgeon in the cases.
"They are back to the home, able to speak, able to socialize with everybody," Giovannini told the Associated Press. "Having this quality of life is wonderful."
According to Dr. Mark Iannettoni, head of the department of cardiothoracic surgery at University of Iowa, a trachea is a fragile organ because it is mostly cartilage, which has a poor blood supply.
"Once damaged, it is difficult to get it to heal correctly," said Iannettoni.
Growing a Working Trachea
Trachea cancer is resistant to chemotherapy and radiation and attempts to replace the trachea with mechanical devices have not been effective.
However, Dr. Eric Lambright, surgical director of lung transplant at Vanderbilt University Medical Center, said that using a patient's own stem cells not only could help to rebuild the fragile tissue, but also potentially could bypass the risk of having the organ rejected.
"These patients [are] otherwise sentenced to rather significant horrible quality of life related to their tumors and ... heroic measures may indeed be very appropriate," said Lambright.
According to Macchiarini, the team collected stem cells from the patients' nose and bone marrow, and grew two different types of tissues from the cells that resembled the different surfaces of the trachea. The tissues covered the outer and inner linings of the donor trachea.
Although these were the first stem cell transplants Macchiarini performed on trachea cancer patients, this is not the first trachea transplant of its kind. In 2008, Macchiarini and his surgical team successfully performed a trachea transplant using adult stem cells on a woman who suffered from tuberculosis.
The team transplanted a new windpipe with tissue grown from her own stem cells and did not need to administer anti-rejection drugs, according to the case report, published in the December 2008 Lancet.
Early Step in the Right Direction, Experts Say
While the procedure seemed to have worked in a few patients, many experts said the method is still in the earliest stages of development.
"This is a research project and not a proven therapy," said Dr. Larry Goldstein, director of the stem cell program at University of California San Diego. "There's an important step from innovative therapy to the research needed to bring the innovative therapy to a large number of people."
In fact, Goldstein said there's a lot more information needed to know exactly how the procedure worked. The hospital did not release the patients' identities or more details about their cases due to privacy concerns, the Associated Press reported.
While this procedure was seemingly successful in a small number of patients, Lambright said it is still early to tell if the procedure works for a larger number of patients.
"We are a long ways away from knowing whether or not any of this has real durable application," said Lambright.
Still, Goldstein said this latest procedure builds on the innovative work by Macchiarini to find a treatment for an otherwise fatal disease.
"It's potentially very exciting," said Goldstein. "The goal for this entire field is to generate new organs and replacement organs, and this is a step in the right direction."
Iannettoni said this procedure could pave the way for other challenging transplants including the heart valve and the esophagus.
"The possibilities are endless once we unlock the potential for bioengineering," said Iannettoni.