Successful transplantation of a tracheobronchial airway
This fascinating report appeared in the Lancet on line in the last couple of weeks (Jungebluth et al Nov 24, 2011). This is a single case report from a team led by Paolo Macchiarini who three years ago reported the first tissue engineered tracheal transplantation with a non immunogenic scaffold of allogeneic human donor trachea reseeded with bone marrow derived mesenchymal stem cells. A 36 year old male patient, previously treated for a tracheal tumour with debulking surgery and radiation therapy was referred with stridor; scans showed an extensive recurrent tumour involving the lower 5 cm of the trachea and extending into the right bronchus.
A synthetic scaffold of the trachea and bronchi of the appropriate size as determined by imaging of the patient’s own trachea was made in a bioreactor over a bifurcated mandril using a nanocomposite polymer. This was seeded with autologous mononuclear cells from the patient’s bone marrow 36 hours before transplantation was to take place. Immediately before transplantation a second bone marrow harvest was done and mononuclear cells were separated and the graft was reseeded with these newly obtained mononuclear cells. Granulocyte colony stimulating factor (GCSF) and epoetin beta were used to enhance the growth of the seeded cells.
At transplantation an extensive resection was done, which also included resection of the right intrapericardial pulmonary artery which was replaced by a Dacron graft. All the tumour margins were negative on frozen section. The synthetic reseeded airway was implanted with anastomosis to the right and left main bronchi and then to the proximal trachea. The patient was treated with subcutaneous injections of GCSF and epoetin-alpha starting the day before transplantation and every other day for two weeks. The immediate post operative recovery was complicated with a right upper lobe pneumonia which responded to antibiotic treatment and the patient was weaned of mechanical ventilation on the 5th post operative days. The patient is now 5 months after transplantation, is asymptomatic, breathing normally and is tumour free on scanning. Lung function is improved compared to the preoperative evaluation.
This is an exciting report, particularly bearing in mind that this was by standard criteria, a non-resectable tumour of the trachea. As the new trachea is a synthetic material seeded with autologous cells there is no requirement for immunosuppression and this must improve the chances of there being no tumour recurrence. There is no question that this is a novel approach for the resection of an otherwise inoperable tumour of the trachea and is an exciting development in tissue engineering.
