In a groundbreaking operation in April 2013, a 2 ½-year-old girl received a functioning trachea (windpipe) after breathing through a plastic tube in her neck since she was born. Hannah Warren was born without a trachea, a very rare condition that is usually fatal.

Hannah’s new windpipe is a bioengineered organ, created using stem cells and plastic fibres, and transplanted in an experimental procedure that has only been done a handful of times, with Hannah being the youngest patient to undergo this operation. Hannah’s surgeon, Dr. Paolo Macchiarini, is a specialist in the field of regenerative medicine who developed the windpipe and directed the nine-hour surgery that was performed at the Children’s Hospital of Illinois by an international team of surgeons.

Did You Know? An aim of regenerative medicine is to fill the supply gap for organ donations and eliminate the need for matching patients with organ donors.

To generate Hannah’s new windpipe stem cells were harvested from her bone marrow. Then a half-inch diameter tube made from plastic nanofibres was bathed in a solution of the stem cells and incubated (grown) in a bioreactor. Once this tube is transplanted, scientists believe that the stem cells signal the body to send or produce other cells that result in the development of specific cells (differentiated cells) that compose the tissue on the inside and the outside of the trachea. By using the patient’s own stem cells there is less risk of rejection of the new organ and no need for immune–suppressing drugs.

Hannah’s transplant surgery was an experimental procedure, meaning that she was a volunteer candidate for a medical procedure that has never been involved in the clinical trial process. A clinical trial involves repeating the same procedure on a number of eligible candidates and collecting data about the safety, side effects, outcomes and effectiveness of the medical procedure. Now that Dr. Macchiarini has done several similar tracheal transplants as experimental procedures he is hoping to get approval in the United States to do an actual clinical trial of this transplant procedure.

So far Hannah is recovering quite well, but she still needs to learn to breath normally and she faces additional surgeries to allow her to eat and speak properly. In about four years as Hannah grows she will also need another trachea that is bigger. Hannah still faces a lot of challenges in the future! What will be the status of this transplant procedure in another four years?

A truly international story…with a Canadian connection!

Hannah Warren was born in Korea. Her mother is Korean and her father is a Canadian from Paradise, Newfoundland who now lives and teaches in Korea. Dr. Paolo Macchiarini is an Italian surgeon who is teaching in Sweden. The co-surgeon, Dr. Mark Holterman, and the international surgical team conducted the operation in the United States at the Children’s Hospital of Illinois in Peoria. Both Koreans and Canadians have provided financial support to the family.For many readers Hannah’s procedure probably sounds like the medicine of science fiction. Today stem cell science is moving towards understanding stem cells and the factors that cause stem cells to differentiate. The generation of simple tissues and organs is being conducted in both animal models and human patients. A bioengineered bladder has been transplanted successfully in a young girl, but complex organs like hearts are still a long way off. Scientists are getting closer to establishing a process for successfully generating 3-dimensional cardiomyocytes (heart muscle cells) from human embryonic stem cells that are a close approximation of human heart tissue.

Bioengineers at Cornell University recently created an artificial human ear using collagen injected with living cartilage cells from a cow and 3D printing to make the form of the ear. Over three months the cartilage cells multiplied and replaced the collagen, making a living and flexible ear. The next big challenge will be to grow a large volume of human cartilage cells in a laboratory. Despite this challenge, researchers at Cornell estimate the first implant of a human ear may happen as soon as three years from now.

What will the future bring for Hannah and other transplant patients like Hannah? Will we be hearing more of these remarkable stories in the future? Who will be the next person or “little person” in the regenerative medicine spotlight?

Stem Cell Tracheal Transplant Saves Girl's Life (Video - 2:29 min.)

Update - May 30, 2013: This article from the Toronto Star features a video interview with the doctor that helped initiate Hannah's transplant process. It also includes some excellent footage of Hannah after her surgery. She can now enjoy a lollipop like other children her age!

Parents of girl, 2, with windpipe transplant breathe easier

Update - July 8, 2013: Sadly, on Saturday, July 6, Hannah Warren died as a result of complications following a second surgery to fix her esophagus which failed to heal correctly after her initial experimental operation on April 9. According to Dr. Macchiarini, "The trachea was never a problem, it was her native tissue that was very fragile.” For this complex and difficult case, the experimental operation was approved by the US Food and Drug administration under rules that allow experimental procedures when the patient otherwise has little hope of survival. Up until this year Hannah had spent her entire life in a newborn intensive care unit in a Korean hospital, breathing through a tube inserted in her mouth. Hannah would have turned three this August. Our sincere condolences go out to Hannah's parents, family and friends.

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Laura Brown

Laura is an Education Specialist with Let’s Talk Science. With a background in agricultural sciences and visual arts, she is interested in most everything, from pigs to Picasso! She developed her love of science and technology from her parents and teachers.

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