Giving new life to old lungs: methods to produce and assess whole human paediatric bioengineered lungs

Abstract

We report, for the first time, the development of an organ culture system and protocols to support recellularization of whole acellular (AC) human paediatric lung scaffolds. The protocol for paediatric lung recellularization was developed using human transformed or immortalized cell lines and single human AC lung scaffolds. Using these surrogate cell populations, we identified cell number requirements, cell type and order of cell installations, flow rates and bioreactor management methods necessary for bioengineering whole lungs. Following the development of appropriate cell installation protocols, paediatric AC scaffolds were recellularized using primary lung alveolar epithelial cells (AECs), vascular cells and tracheal/bronchial cells isolated from discarded human adult lungs. Bioengineered paediatric lungs were shown to contain well-developed vascular, respiratory epithelial and lung tissue, with evidence of alveolar-capillary junction formation. Types I and II AECs were found thoughout the paediatric lungs. Furthermore, surfactant protein-C and -D and collagen I were produced in the bioengineered lungs, which resulted in normal lung compliance measurements. Although this is a first step in the process of developing tissues for transplantation, this study demonstrates the feasibility of producing bioengineered lungs for clinical use. Copyright © 2016 John Wiley & Sons, Ltd.

Lung Microvascular Niche, Repair, and Engineering

“…For generating ECs from stem cells, Cortiella's group showed that mouse embryonic stem cells (ESCs) differentiated into CD31 positive cells on pulmonary ECM (Cortiella et al, 2010;Nichols et al, 2017). More recently, induced pluripotent stem cells (iPSCs) have been broadly investigated as a promising cell source for ECs (Ren et al, 2015a).…”

Lung bioengineering: physical stimuli and stem/progenitor cell biology interplay towards biofabricating a functional organ

“…In addition, Ott et al [13] and Petersen et al [14] recellularized rodent lung scaffolds with lung cells to obtain bioengineered lungs, showing limited short-term functionality of gas exchange after in vivo implantation. Although these works represented a milestone in the birth of lung bioengineering, any potential future routine application following the approach of these authors could be hampered by the problem of using differentiated cells, given their limited availability and proliferative capacity [15]. …”

“…Interestingly, the vascular resistance and barrier function of the new endothelium were optimized in vitro and 3-day after transplantation in rats the vessels remained patent. Another relevant study recently published describes human lung recellularization in a bioreactor culture and compares distinct methods of obtaining and seeding cells in adult and pediatric lungs [15]. The authors succeeded in repopulating pediatric lung scaffolds using primary lung-derived vascular, epithelial and tracheal/bronchial cells, resulting in bioengineered lungs with the presence of type I and II alveolar epithelial cells along the whole organ, alveolar-capillary junctions and increased collagen I content when compared to the decellularized scaffold.…”

Laminin-driven Epac/Rap1 regulation of epithelial barriers on decellularized matrix

“…Insufficient recellularization and immature barriers keep this technology from the clinic. Most of the research to date has focused on assessments of stem cell differentiation and attachment [1][2][3][4] or mimicking lung development during regeneration [5,6]. More recently, researchers in this field have examined recellularization on a smaller scale by evaluating endothelial barriers [7]; however, there is little research on epithelial barrier formation with recellularized lungs.…”