Experimental orthotopic implantation of tissue-engineered tracheal graft created based on devitalized scaffold seeded with mesenchymal and epithelial cells

Abstract

Aim. To study the viability of the tissue-engineered graft (TEG) based on the devitalized tracheal scaffold (DTS), seeded by mesenchymal stromal and epithelial cells in the experiment on rabbits with the assessment of the cytocompatibility and biocompatibility in vivo. Materials and methods. Syngeneic bone marrow-derived mesenchymal stromal cells (BM-MSCs) and lung epithelial cells of rabbit were obtained. Morphology and phenotype of the BMSCs culture were confirmed by immunofluorescent staining on CD90 and CD271 markers. Pulmonary epithelium cells obtained by enzymatic treatment of shredded lung tissue of rabbit were stained with CKPan, CK8/18 and CK14 markers of epithelial cells. The donor trachea was devitalized in three freeze-thawing cycles. Double-layer cell seeding of DTS was performed under static and dynamic culturing. Orthotopic implantation of TEG was performed at the site of the anterolateral wall defect in the rabbit trachea formed as a result of tracheal resection over four rings. The results were evaluated by computed tomography, histological and immunohisto- chemical analyses. Results. TEG implant based on DTS with two-layer cell cultures of rabbit BM-MSCs and epithelial cells was obtained. Three months after the implantation, TEG engraftment was observed, no tracheal wall stenosis was observed, but a slight narrowing of the lumen in the implantation area was observed. Viability of the tissue-engineered graft was confirmed by histological method 6 months after implantation. Epithelialization and vascularization of the tracheal wall, absence of signs of purulent inflammation and aseptic necrosis were shown. Small narrowing of the tracheal lumen was caused by chronic inflammation produced by irritation of the mucous suture material. Conclusion. The new model for evaluating the viability of a tissue engineering implant during critical airway defect closure was obtained. Two-layer vitalization of DTS with lung epithelial cells and BM-MSCs allows to create a tissue engineered structure for replacement of non-long tracheal defects in the experiment in vivo. The use of the tracheal tissue-engineered graft for orthotopic implantation showed a biocompatibility with minimal tissue reaction.