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Objective: This study aimed at examining a hybrid airway construct engineered from autologous amniotic mesenchymal stem cells (aMSCs) and a xenologous decellularized airway scaffold as a means for prenatal tracheal repair.

Design: Fetal lambs (n=13) with size-matched complete tracheal defects were divided into two groups. One group (acellular, n=6) was repaired with a decellularized leporine tracheal segment previously exposed to a detergent-based decellularization protocol over 3 months. The other group (engineered, n=7) received an identical graft seeded with autologous aMSCs procured earlier in gestation. Cell processing included phenotyping, labeling with green fluorescent proten (GFP), and expansion in culture. Engineered constructs were maintained under hydrodynamic stimulation in chondrogenic medium supplemented with TGF-β and IGF-1 before implantation. Newborns were euthanized for multiple analyses.

Main Outcome Measure(s): Survival to delivery, respiratory status in the neonatal period, tracheal diameter and epithelialization patterns, extracellular matrix analysis (including elastin, collagen, and glycosaminoglycan content), presence of donor cells in engineered grafts

Results: Eleven lambs survived to term, 10 of which could breathe at birth. Engineered grafts showed a significant increase in diameter in vivo (P=0.04), unlike acellular grafts (P=0.62), though variable stenosis was present in all implants. Engineered constructs exhibited full epithelialization, compared to none of the acellular grafts (P=0.002). Engineered grafts had a significantly greater degree of increase in elastin levels after implantation than acellular implants (P=0.04). No such differences were noted in collagen and glycosaminoglycan contents. Donor cells were detected in engineered grafts, which displayed a pseudostratified columnar epithelium.

Conclusions: Constructs engineered from amniotic mesenchymal stem cells and decellularized airway undergo enhanced remodeling and epithelialization in vivo when compared with equivalent acellular implants. Amniotic mesenchymal stem cellengineered airways may become an alternative for perinatal airway repair.