Use of high-rate ventilation results in enhanced recellularization of bio-engineered lung scaffolds

While transplantation is a viable treatment option for end-stage lung diseases, this option is highly constrained by the availability of organs and postoperative complications. A potential solution is the use of bio-engineered lungs generated from repopulated acellular scaffolds. Effective recellularization, however, remains a challenge. In this proof-of-concept study, mice lung scaffolds were decellurized and recellurized using human bronchial epithelial cells (Beas2b). We present a novel liquid ventilation protocol enabling control over tidal volume and high rates of ventilation. The use of a physiological tidal volume (300uL) for mice and a higher ventilation rate (40 breaths per minute versus 1 breath per minute) resulted in higher cell numbers and enhanced cell surface coverage in mouse lung scaffolds as determined via histological evaluation, genomic PCR analysis and immunohistochemistry. A biomimetic lung bioreactor system was designed to include the new ventilation protocol and allow for simultaneous vascular perfusion. We compared the lungs cultured in our dual system to lungs cultured with a bioreactor allowing vascular perfusion only and showed that our system significantly enhances cell numbers and surface coverage. In summary, our results demonstrate the importance of the physical environment and forces for lung recellularization.