Tracheal Replacement Therapy with a Stem Cell-Seeded Graft: Lessons from Compassionate Use Application of a GMP-Compliant Tissue-Engineered Medicine.

Tracheal replacement for the treatment of end-stage airway disease remains an elusive goal. The use of tissue-engineered tracheae in compassionate use cases suggests that such an approach is a viable option. Here, a stem cell-seeded, decellularized tissue-engineered tracheal graft was used on a compassionate basis for a girl with critical tracheal stenosis after conventional reconstructive techniques failed. The graft represents the first cell-seeded tracheal graft manufactured to full good manufacturing practice (GMP) standards. We report important preclinical and clinical data from the case, which ended in the death of the recipient. Early results were encouraging, but an acute event, hypothesized to be an intrathoracic bleed, caused sudden airway obstruction 3 weeks post-transplantation, resulting in her death. We detail the clinical events and identify areas of priority to improve future grafts. In particular, we advocate the use of stents during the first few months post-implantation. The negative outcome of this case highlights the inherent difficulties in clinical translation where preclinical in vivo models cannot replicate complex clinical scenarios that are encountered. The practical difficulties in delivering GMP grafts underscore the need to refine protocols for phase I clinical trials. Stem Cells Translational Medicine 2017;6:1458-1464.

Congenital absence of cartilaginous tracheal rings associated with esophageal atresia and trifurcated carina: a novel anomaly?

Tracheomalacia associated with esophageal atresia (EA) is a well-known condition. However, complete absence of tracheal rings (TRs) is extremely rare. Our aim is to describe a novel triad of conditions and to discuss the best treatment. An expremature male operated for EA presented with severe respiratory distress. The diagnosis of absent cartilage rings, suspected on bronchoscopy, was confirmed by optical coherence tomography. The absence of TRs was localized to a short tracheal segment, and the carina trifurcated into right upper lobe, right intermediate, and left main bronchus. The patient was treated with resection and anastomosis with a completely satisfactory course. Absence of TRs was previously reported by us in 2 other cases, both with associated EA and trifurcation of the carina. One child was treated with tracheostomy and the other with a stent, but the outcome was far from optimal. The patient with tracheostomy eventually underwent resection and anastomosis with tracheostomy closure. Congenital absence of TRs is extremely rare. Although localized, it is responsible for severe symptoms owing to complete tracheal collapse and may be misdiagnosed as tracheomalacia. In our experience, it has been associated with EA and trifurcated carina. Our limited experience suggests resection of the abnormal segment and tracheal anastomosis as the best treatment.