Stem Cell-Based Organ Transplants Emerging as Alternative to Conventional Donations

Steven Zeitels, MD, professor of laryngeal surgery at Harvard Medical School in Boston, has been using cadaver aortas to reconstruct the larynx. “Patient 1,” on whom he operated in 2009 with thoracic surgeon John Wain, MD, was an 88-year-old man with laryngeal cancer who had failed radiotherapy but did not want a total laryngectomy. Dr. Zeitels credits Dr. Wain with the idea for the aortic patch. “You have an acellular piece of tissue that you’re putting into an environment with just the random blood supply from the muscles that are sutured into it,” he said. “The tissue is extremely easy to suture, like sewing a piece of rubber, and the aorta has a natural curve that can be fitted into the defect to form an adequate airway. And it is relatively sturdy; it does not fall apart.”

Success was far from guaranteed, Dr. Zeitels added. “Think of how hostile the environment is: You have an avascular piece of tissue and a random blood supply on only one side, and you’re not putting it in a part of the body where you can maintain sterility, [and] all kinds of flora exist in the human airway. There is also [gastric acid reflux] and, finally, the patient is coughing, so there’s barotrauma. On top of all of that, it’s an irradiated field. So it was stunning to me that it actually worked.” He estimates that approximately 25 patients have undergone the procedure so far, most of whom can start eating normally within a few days. Currently, the indications are for cancer and intractable stenosis.

As for “Patient 1,” he is now in his 90s, travels with his girlfriend and sends Dr. Zeitels a postcard every six months to let him know he is still doing well.

Building from Within

Tissue engineering is also being explored for its potential in the repair of craniofacial defects. At Washington University School of Medicine in St. Louis, head-and-neck surgeon Brian Nussenbaum, MD, is experimenting with bone morphogenetic proteins (BMPs) to regenerate bone in patients with defects related to trauma or oral cancer. Irradiated tissue is usually hypoxic or hypocellular, and the blood vessels may be scarred, which compounds the risks of reconstructive surgery, he said. BMPs, the central molecules involved in bone regenerative approaches, offer the potential for reconstructing tissue without many of the drawbacks associated with surgery. Essentially, “any bone regeneration strategy will involve BMPs,” he said.