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A2671 - De- and Recellularization of Avian Lungs: Exploring New Frontiers for Lung Bioengineering
Author Block: J. J. Uriarte1, H. Park2, F. E. Uhl1, S. M. Wrenn1, E. D. Griswold3, J. Dearborn1, B. A. Ahlers4, B. Deng4, Y. W. Lam4, D. R. Huston2, P. C. Lee2, D. E. Wagner5, D. J. Weiss1; 1Pulmonary Medicine, The University of Vermont, Burlington, VT, United States, 2Mechanical Engineering, The University of Vermont, Burlington, VT, United States, 3RIT, Rochester, NY, United States, 4Biology, The University of Vermont, Burlington, VT, United States, 5Comprehensive Pneumology Center (CPC), Ludwig-Maximilians-Universität,, Munich, Germany.
Rationale: Respiratory diseases are a leading cause of death worldwide with lung transplantation as the only treatment currently available to end-stage disease patients. Allogeneic lung transplantations are limited by the shortage of available donor lungs and by the lack of suitable long term lung assist devices to bridge patients to lung transplantation. Avian lungs have a different structure and different mechanics resulting in more efficient gas exchange than mammalian lungs. Therefore, bioengineering of functional lung tissue by using decellularized bird lungs and recellularizing them with human lung cells could provide a powerful novel gas exchange unit for potential use in pulmonary therapeutics. Methods: Lungs from a small-size avian model (chicken) were decellularized utilizing a modifications of a detergent-based protocol successfully applied with mammalian lungs. Vascular (Rv) and airway resistance (Ra) were assessed before and after decellularization. The main parabronchi and pulmonary artery were cannulated individually and connected to a perfusion system with continuous pressure of 25cmH2O (gravimetric level). Decellularization success and structural integrity were analyzed by histological and immunohistochemistry staining, SEM, and DNA quantification. Avian-derived extracellular matrix (ECM) hydrogels were seeded with bronchial epithelial (HBE), human lung fibroblasts (HLF), pulmonary vascular endothelial (CBF, HUVEC), or human mesenchymal stromal (hMSC) cells to determine cell proliferation. Additionally, recellularization of the whole scaffold was performed by seeding HBE or HLF via the airways or CBF, HUVEC, or hMSC via the vasculature with subsequent bioreactor cultivation for up to 3 days. Results: Acellular avian lungs demonstrated maintenance of lung structure, minimal residual DNA and retention of major ECM proteins. Ra decreased from 0.99 ± 0.79 before decellularization to 0.51 ± 0.27 and 0.48 ± 0.16 cmH2O·s·mL-1 after DNAse and peracetic acid (PAA) treatment, respectively. Rv also decreased after the decellularization process (native = 9.24 ± 6.02, after DNAse = 2.96 ± 1.71 and after PAA = 4.86 ± 1.92 cmH2O·s·mL-1). HMSC cells seeded on top of ECM hydrogel demonstrated a proliferation of ~70% compared to control while no proliferation of CBF and HBE cells on the gels was observed. Whole lung scaffolds seeded with CBFs, HUVECs, or hMSCs displayed a remarkable repopulation of endothelial compartments over a 3-day period in a bioreactor system, while HBEs and HLFs demonstrated more limited attachment in the airways. Conclusion: Decellularized and recellularized avian lungs are novel and innovative platforms for development of lung assist device.