Stem Cells Spawn First Drug-Free Windpipe Transplant

By Michelle Fay Cortez
Nov. 19 (Bloomberg) — Doctors operating on a 30-year-old Colombian woman restored her ability to breathe freely with the world’s first transplanted windpipe specially treated to prevent organ rejection.

The airway connecting Claudia Castillo Sanchez’s left lung to her windpipe collapsed after a persistent tuberculosis infection, leaving her short of breath and unable to perform routine daily activities. Efforts to prop it open failed, leaving Spanish doctors two options: remove the lung or replace the airway using an experimental technique tried only in animals.

The donor windpipe, or trachea, was washed 25 times to strip away all vestiges of live tissue, which could trigger rejection, then coated with cartilage cells grown from Castillo’s own adult stem cells to trick her body into accepting the transplant, the doctors said in The Lancet. She was released from the hospital 10 days after the June operation and isn’t taking drugs to suppress her immune system, a standard approach to prevent the body from rejecting transplanted organs.

“We think that this first experience represents a milestone in medicine and hope that it will unlock the door for a safe and recipient-tailored transplantation of the airway in adults and children,” said the physicians, led by Paolo Macchiarini, head of the thoracic surgery department of the Hospital Clinic in Barcelona.

Difficult To Treat
Damage to the large airways — the trachea that runs down the throat and the bronchial tubes that connect it to the lungs – – is difficult to treat. Previous grafts of more than six centimeters (2.4 inches) have failed, so the successful transplant of the seven-centimeter windpipe for Castillo’s left main bronchus suggests tissue-coated replacements may become an alternative for treating diseases of the upper airways.

Castillo hasn’t produced any antibodies against the donor windpipe and her lung function is in the normal range for a woman her age, doctors said. She is able to walk 500 meters (1,600 feet) without stopping, climb stairs and take care of her children, aged 4 and 15.

Macchiarini performed the operation in Barcelona and was the lead investigator on the grant used to conduct the preliminary work. The cleansing of the trachea, from a 51-year-old woman who died of a brain hemorrhage, was done using a technique created at the University of Padua in Italy.

Stem Cells
Castillo’s stem cells were extracted from her bone marrow then grown into cartilage cells at the University of Bristol in the U.K. The donated trachea was coated on the outside with the cartilage cells and lined on the inside with Castillo’s healthy epithelial cells to create a hybrid organ using an incubator developed at Politecnico di Milano in Italy.

“Just four days after transplantation the graft was almost indistinguishable from adjacent normal bronchi,” Macchiarini said in a statement. “After one month, a biopsy elicited local bleeding, indicating that the blood vessels had already grown back successfully.”

The initial results of the surgery are impressive, wrote Toshihiko Sato and Tatsuo Nakamura, from Kyoto University’s Institute for Frontier Medical Sciences, in a comment that accompanied the study. More information and follow-up is needed to fully evaluate the results, they said.

The bio-engineered approach of using donor scaffolds coated with tissue grown from the patient’s own stem cells may one day be used for other types of transplants, the investigators said.

“Surgeons can now start to see and understand the very real potential for adult stem cells and tissue engineering to radically improve their ability to treat patients with serious diseases,” said Martin Birchall, who oversaw the growing of the stem cells at the University of Bristol. “We believe this success has proved that we are on the verge of a new age in surgical care.”

To contact the reporter on this story: Michelle Fay Cortez in London at mcortez@bloomberg.net