Breakthrough in tissue engineering: bronchus from stem cells
In Spain, the world's first operation was performed to transplant a human trachea purified from donor cell antigens. The new organ, consisting of an alien "skeleton" and the patient's own epithelial and cartilage cells, successfully functions without the use of immunosuppressants, The Lancet magazine reports.
The patient, 30-year-old Claudia Castillo, suffered from chronic tracheitis (inflammation of the trachea) and loss of elasticity of the left main bronchus caused by tuberculosis.
Due to the violation of bronchial patency, the patient's left lung could not function normally. The traditional method of treatment in such situations is the removal of the lung, but the surgeon Paolo Macchiarini and his colleagues from the Clinical Hospital of Barcelona decided to use an experimental technique that had previously been tested only on pigs.
At the first stage, a 7–centimeter section of the trachea was taken from the donor – a woman who died from a stroke. With the help of a special solution, he was completely cleansed of all cells that can cause immune reactions in the recipient.
As a result, scientists have obtained a tissue framework consisting of collagen protein. At the same time, a culture of cells grown from the epithelium of the bronchi of the patient herself was prepared. To obtain chondrocytes – cartilage tissue cells – specialists used stem cells taken from the patient's bone marrow.
At the next stage, the finished connective tissue frame was covered from the inside with bronchial epithelial cells, and from the outside with cartilage tissue cells, after which the organ was placed in a bioreactor. After 96 hours, the epithelial cells and chondrocytes "fused" with the skeleton, and the new organ was ready for transplantation.
During the operation, Castillo had his left main bronchus removed, replacing it with a graft. The procedure was successful, and the patient's left lung immediately began to perform its functions. After 10 days, Castillo was discharged home.
By now, four months have passed since the operation. The patient feels well. She is able to overcome two flights of stairs and walk 500 meters without stopping, and she also successfully copes with two children. Studies have shown no signs of bronchial inflammation, as well as the absence of antibodies against a foreign organ. Computed tomography confirmed that the patency of the bronchi is not impaired.
Doctors continue to closely monitor the patient. In the absence of late complications, the new technique can find its application in patients with cancer and other severe respiratory diseases, experts say.
Medpage Today, 18.11.2008: Airway Transplant Shows Potential of Stem Cells for Tissue Engineering
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19.11.2008