19 November 2008

Stem cells rebuild patient’s windpipe

Agence France-Presse
The pioneering transplant of a windpipe stripped of its cells and seeded with recipient stem cells has given a 30-year old Colombian woman a new lease on life.
Respiratory tract

Replacement body part: A diagram of the upper respiratory tract, showing the trachea or windpipe that was rebuilt with a patient's own stem cells. Credit: Wikimedia/Arcadia

PARIS: The pioneering transplant of a windpipe stripped of its cells and seeded with recipient stem cells has given a 30-year old Colombian woman a new lease on life.

The operation is the first of its kind, and shows that adult stem cells combined with re-engineered biological materials can “radically improve the ability of surgeons to treat patients with serious diseases,” said Martin Birchall, a professor at the University of Bristol in Britain, and one of the study’s authors.

“Verge of a new age”

“We believe this success has proved that we are on the verge of a new age in surgical care,” he said. The study is published today in medical journal The Lancet.

The loss of a normal airway is devastating, and attempts to replace them have met with serious problems such as rejection by the immune system, the uncontrolled die-off of cells, called necrosis, and lethal bleeding.

Claudia Castillo, stricken with tuberculosis, was facing the loss of her left lung after the tube-like branch connecting it to the trachea, or windpipe, became infected and collapsed beyond repair. Doctors explained that they could try an untested method to replace the ruined airway.

“I was scared at the beginning because I was the first patient, but had confidence and trusted my doctors,” Castillo said in a press release. “The possibility of avoiding the removal of my entire lung – and instead replacing only my diseased bronchus – represented a unique chance for me to return to a normal life.”

High-tech detergent

With her green light, a team of scientists and surgeons from Spain, Italy and Britain each contributed specialised knowledge to the task.

Using a new technique developed at the University of Padua, scientists removed all the cells from the trachea of a dead 51-year old donor by scrubbing it clean with a high-tech detergent and enzyme solution. This left a ‘biological scaffold’ of connective tissue.

The next steps were to reconstitute the living tissue using Castillo’s own stem cells, and graft them onto the scaffolding.

Stem cells were obtained from her bone marrow, and cultivated in large numbers in Birchall’s laboratory in Britain. They were then coaxed – using growth-stimulating proteins – into becoming structure-giving cartilage cells using a method originally devised for treating osteoarthritis.

The surface of the donor’s sterile trachea was seeded with these lab-grown cells using a bioreactor that allowed them to migrate into the tissue. Next the trachea was colonised with epithelial cells, which help the major airways keep clean by moving foreign objects away from the lungs.

Finally, Castillo’s damaged airway was surgically removed and replaced with the rebuilt windpipe. The operation was entirely successful, the authors report.

Perfect copy

“Within four days after transplantation, the graft was almost indistinguishable from adjacent normal bronchi,” said Paolo Macchiarini, a professor at the University of Barcelona, where the operation was performed, and lead author of the study.

And only ten days after surgery, Castillo left the hospital to rejoin her two children, aged 15 and four.

“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,” the authors conclude.

For Castillo the results are already tangible: “I am now enjoying life and am very happy my illness has been cured,” she said.

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