New Surgery to Transplant the Trachea
A throat and voice specialist participated in a revolutionary new surgical technique in March 2011, when a 10-year old boy from the UK was given a transplanted trachea. The boy needed the new trachea because he was born with a congenital condition in which the trachea does not grow at birth. This means that the main airway that leads from the back of the throat into the lungs does not increase in size as the body grows, leading to severe breathing difficulties. Untreated, it is rapidly fatal.
Although the boy had received a tracheal transplant shortly after he was born, this had started to fail and surgeons had placed a stent in the airway to stop it collapsing. This metal stent was rubbing on the boy’s aorta, the main artery that comes out of the heart to take oxygenated blood around the body. He had several life-threatening bleeds as the wall of the aorta became increasingly damaged.
Stem Cell Transplant for the TracheaThe operation that saved his life involved repairing the damage to his aorta and simultaneously giving him a newly transplanted aorta. This time stem cells were used within the graft to aid healing and to make it less likely that is body will reject the new tissue. This is the first stem cell whole organ transplant ever to have been done on a child. The surgeons who devised the technique and the operation had previously done the first stem cell transplanted organ transplant on an adult, in 2008.
The trachea is a tube made mainly of connective tissue – it contains few cells. The team stripped the donor trachea entirely of cells, so that it contained no cells at all from the donor. This in itself makes rejection less likely. They then took the boy’s own stem cells, obtaining two different types just before the surgery began. They then repopulated the trachea with these cells, and sealed the airways at the lung and throat end.
What are Stem Cells?Stem cells are cells in the body that can grow, divide and specialise to become one of several possible cell types. The ultimate stem cell is the fertilised embryo. This one cell gives rise to every cell in the body from hair follicle cells, to brain cells, to kidney tubule cells. Embryonic stem cells can be used for medical therapies but the ethics of this do not sit well with some people. Using a patient’s own stem cells is more acceptable. These are in short supply though – only a few circulate in the body and are present in different tissues. Locating and harvesting them is a very skilled procedure but as this has been perfected, it has opened up opportunities for more operations of this type.
Previous Tracheal Transplant SuccessA 30-year old Spanish woman, who received a transplanted trachea in 2008, is now fit and healthy despite hardly being able to walk and speak because her breathing was so poor before the surgery. The stem cell transplant component of the technique means that the patient’s own cells are present in the trachea when it is transplanted. Growth factors are injected along with the cells to encourage them to grow and then the healing process of the body takes over. The trachea scaffold becomes lined on the outside and inside by the patient’s own tissue, which grows to produce normal mucosa. After several months, the trachea resembles the own patient’s trachea very closely and functions well.
It is too early to say what the long term prospects of patients who receive tracheal transplants using their own stem cells will be but the technique seems extremely promising. It could offer hope of a transplant of a trachea and also of an oesophageal transplant for patients with illness such as cancer and infection, which damage the body’s own tissues so severely.