D1.4 Oesophageal tissue engineering: preliminary evaluation of a 2 stage surgical approach in a mouse model

Background Oesophageal atresia is a birth defect occurring in approximately 1 in 2500 live births. Tissue engineering is a promising therapeutic alternative for those patients requiring oesophageal replacement. Aim of this study is to evaluate the engraftment in vivo of the muscle compartment of an engineered rat oesophagus in a mouse model of heterotopic xeno-genic implant and to prove its capability to grow an epithelial layer ex vivo . Methods The detergent-enzymatic protocol was used to produce decellulirised rat oesophagi. Those were subsequently repopulated with smooth muscle (human mesoangioblasts) and neural (mouse neural crest stem cells) precursor. A 3D culture protocol in a bioreactor was used to maximise the cells engraftment, proliferation and differentiation in vitro . 4 engineered oesophagi were implanted in 4 immunodeficient mice and left in situ . After 2 weeks the animals were euthanised and the engineered organs harvested and seeded, on the luminal surface, with epithelial progenitors derived from rat oesophagi. Results Engraftment, proliferation and differentiation of both muscle and neural cells were achieved during the initial in vitro culture as evident from the immunofluorescence. Those features were also preserved after the implant in the mice omentum. The immunofluorescence showed the presence of new vessels inside the artificial oesophagi when harvested from the mice. The engineered oesophagi were able to grow an epithelial layer when progenitors were seeded ex vivo . Conclusion The effectiveness of the in vivo implant of the engineered oesophagi was demonstrated, underlying the survival of both muscle and neural cells thanks to angiogenetic phenomena. The generation, ex vivo , of an epithelial layer is really promising, making realistic a 2 stage surgical approach for clinical translation.