Artificial Tracheal Recipient Returns to Academic Study

Larry Hand

November 28, 2011

November 28, 2011 — The patient who received the world's first transplant of an artificial tracheobronchial airway seeded with his own stem cells now has almost normal lung function and is tumor free, according to a report published online November 24 in the Lancet.

Swedish doctors, led by Paolo Macchiarini, MD, PhD, from the Karolinska Institutet in Stockholm, performed the surgery in June at the Karolinska University Hospital. The 36-year-old patient had respiratory difficulties due to a recurrent tracheal tumor that extended into both bronchi. The surgeons removed his trachea, along with the complete right main bronchus and the first 2 cm of the left main bronchus, and replaced it with the artificial organ.


Prior to surgery, the physicians constructed a patient-specific artificial trachea based on a chest computed tomography image and 3-dimensional volume-rendered images of the patient. They used a nanocomposite polymer material to make the organ. They seeded the organ with the patient's stem cells using a bioreactor.

"This finding provides evidence that a bioengineered tracheobronchial nanocomposite can be recellurized in vivo with site-specific cells to become a living and functional scaffold completely integrated into the adjacent tissues," the authors write.

Dr. Macchiarini and colleagues constructed the artificial organ using a nanocomposite of polyhedral oligomeric silsesquioxane (POSS) and poly-(carbonate-urea)urethane (PCU). The POSS–PCU nanocomposite "is biocompatible, nontoxic, nonbiodegradable, inert, and has negligible immunoreactivity," they write. In addition, the artificial organ is patient-specific, can be designed to replace the bronchi along with the trachea, and can be produced rapidly enough for clinical use.

The patient underwent surgery and radiation for his primary tumor elsewhere, but was referred to the Karolinska Hospital in May with recurrent disease. The transplant surgery took place in June.

A traditional method of treating tracheal cancers is to surgically remove the tumor and reconstruct the areas affected. However, most patients are not suitable for the surgery because less than 50% of their total tracheal length is disease-free, the authors explain. Patients who have inoperable disease are offered palliative care and have a 5-year survival rate of less than 5%. Whereas previous surgeries have relied on donated organs, the POSS–PCI nanocomposite eliminates the wait for donor organs, which can be long, the authors note.

"The patient has been doing great for the past 4 months, and has been able to live a normal life," said coauthor Tomas Gudbjartsson, MD, PhD, the cardiothoracic surgeon from the University of Iceland in Reykjavik who referred the patient to Karolinska, in a statement. "For the past 2 months, he has been able to focus on his studies [for a Master of Science degree]; the plan is that he will defend his thesis at the end of the year."

The authors report receiving funding from the European Commission, Knut and Alice Wallenburg Foundation, Swedish Research Council, Stratgen, Vinnova Foundation, Radiumhemmet, Clinigene EU Network of Excellence, Swedish Cancer Society, Center for Biosciences Live Cell Imaging Unit, and UCL Business.

Lancet. Published online November 24, 2011. Abstract


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