Second synthetic trachea transplant shows promise of tissue engineering, regenerative medicine

Today brought the news of a second transplanted synthetic trachea seeded with a person’s own stem cells. As with the first such transplant, carried out last June, this one replaced the trachea in a person whose own windpipe had been damaged by cancer.

The timing on this story is exciting for us at CIRM. We’re currently hosting a group of tissue engineering experts—including Martin Birchall who was part of the team that carried out the first tissue engineered tracheal transplant—to help the agency understand how we could move the field forward. Other people at this workshop are working on projects to develop intestines, repair hearts, and generate synthetic polymers to help keep stem cells intact and alive during a transplant.

CIRM president Alan Trounson was quoted in the New York Times story about the transplant. He said that he was worried about the patient’s body responding to the foreign object and encapsulating it:

While he described Dr. Macchiarini’s work as “terrific,” he said he was not sure how long such a transplant could be expected to last.

“It looks very functional at this stage,” Dr. Trounson said. “But there’s going to be a reaction of some kind.” More work will probably be needed to develop scaffold materials that are optimized to reduce the response,” he added. This concern about preventing the body from rejecting engineered structures is one that has come up regularly among the experts CIRM is meeting with today. Another major topic of discussion is how to prove to the Food and Drug Administration that engineered structures are safe for use in humans.

In September CIRM held a webinar on scaffolding that included speakers from the FDA. One goal of that webinar was to help inform researchers about the regulatory process for developing stem cell therapies based on engineered scaffolding, such as the trachea. We’re hoping that through these webinars and by speaking with experts in the field, CIRM can help bring this promising area of research to more patients. That webinar and the associated slides are available on our website.

A.A.