Cell-based therapy improves cell viability and increases airway size in an explant model.

Cell-based therapy is a promising treatment option for lung disease, but no studies have demonstrated its benefit in promoting perinatal lung growth. Embryonic day 18 (E18) fetal lungs treated with vascular inhibitors were grown as explant organ cultures to inhibit endothelial growth in the explant cultures. Disruption of pulmonary vasculature decreased explant mean cord length and viability, whereas coculture with fetal pulmonary or predifferentiated embryonic stem cells rescued both parameters. These results demonstrate in a model of perinatal lung growth, exogenous addition of fetal pulmonary cells or differentiated embryonic stem (ES) cells promotes survival and alveolar morphogenesis. These experiments represent the first evidence of the benefits of cell-based therapy for perinatal lung growth.

Efficient derivation of alveolar type II cells from embryonic stem cells for in vivo application.

In the present study, mouse embryonic stem cells (ESCs) were differentiated into alveolar epithelial type II (AEII) cells for endotracheal injection. These enriched lung-like populations expressed lung epithelial markers SP-A, SP-B, SP-C, and CC10. First we show that rapid differentiation of ESCs requires a dissociated seeding method instead of an embryoid body culture method. We then investigated a two-step differentiation of ESCs into definitive endoderm by activin or A549-conditioned medium as a precursor to lung epithelial cells. When conditioned medium from A549 cells was used to derive endoderm, yield was increased above that of activin alone. Further studies showed that Wnt3a may be one of the secreted factors produced by A549 cells and promotes definitive endoderm differentiation, in part, through suppression of primitive endoderm. Activin and Wnt3a together at appropriate doses with dissociated cell seeding promoted greater endoderm yield than activin alone. Next, fibroblast growth factor 2 was shown to induce a dose-dependent expression of SPC, and these cells contained lamellar bodies characteristic of mature AEII cells from ESC-derived endoderm. Finally, ES-derived lung cells were endotracheally injected into preterm mice with evidence of AEII distribution within the lung parenchyma. This study concludes that a recapitulation of development may enhance derivation of an enriched population of lung-like cells for use in cell-based therapy.