Tracheal Transplant Brings High Hopes for Tissue Engineering

Without the transplant, the woman’s hopes were dim. The only solution for this particular woman, who had both tracheal and bronchial compromise, was to take out her entire left lung and lower trachea and sew a stump of the right lung onto the bottom of the larynx, Dr. Birchall said. That has a 50 percent mortality rate, and the people who survive have very little functional capacity for the rest of their lives.

When you try new things, he said, you need a little serendipity. The patient’s mother had once turned down a new treatment for heart disease, but later died. For that reason, she was accepting, possibly, of something that had only previously been tried in pigs and mice, Dr. Birchall said.

Tracheal Transplant Tried

The center received ethical permissions from the Catalan Transplant Organization. And in March 2008, a human donor trachea was retrieved and treated with the detergent-enzymatic method for 25 cycles.

It was placed in the bioreactor with cartilage cells and epithelial cells from the patient, with hopes that the two would mix nicely. Both nasal and bronchial cells were tested for the epithelial cells. But the nasal cells actually grew too quickly, so the bronchial cells were used.

Doctors knew they still had the pneumonectomy as a last-ditch back-up measure if the specimen didn’t turn out well. We didn’t know what we were going to get, Dr. Birchall said. When we took it out of the bioreactor, it was beautiful.

The patient had her operation on June 12, 2008. The diseased bronchus was removed and replaced with the tissue-engineered trachea. The elasticity of the tissue allowed it to be fitted well to the larynx and the bronchi, he said.

While Dr. Birchall called it beautiful, he did admit it was pale because it wasn’t vascularized, but that soon changed. There was not good mucociliary function for two months, but that also improved, he said.

The woman went home after 10 days but was breathing on her own in half that time. She could have gone home after five days, in fact, Dr. Birchall said. In a month, she had normal lung function.

Typically, if a graft is going to be rejected, a person’s system develops antibodies to a graft within two months, but it’s been a year for this patient. She’s been on no immunosuppressant and never has been, he said.

Dr. Birchall is encouraged by the results but is careful not to get carried away. It’s only one patient, he said. It’s only by repeating this experience and incrementally getting it better and better that we will really prove whether this has any long-term prospects.

Small Steps Yield Large Gains

History has shown that little steps can end up yielding big gains.