Researchers seeded type II lung epithelial cells into a decellularized lung matrix to study their function and report the unexpected finding that instead of differentiating into type I lung cells, they instead transitioned to become mesenchymal cells, as would occur in wound healing. The design and results of this study and its implications for the development of protocols and cell culture environments to support the growth of functional lung tissue are presented in a recently published article.
Elizabeth Calle and coauthors from Yale University and Yale University School of Medicine, New Haven, CT, and University of North Carolina, Chapel Hill, NC, emphasize the effect that factors such as the use of one or more cell populations to seed a tissue matrix, the components of the growth medium, and the use of stimuli such as ventilation to achieve a physiologically appropriate environment can have on the growth and maturation of the lung tissue.
In the article, the authors describe the type II lung epithelial cells isolated from rats and seeded onto decellularized rat lung scaffolds as having migratory, contractile, and matrix-secreting properties after 1 week, which is atypical of epithelial cells. The cells also had increased expression of markers consistent with mesenchymal cell types. In contrast, the authors report that this type of epithelial-to-mesenchymal transition did not occur when mixed populations of rat cells were seeded on the same scaffold using the same media.
"Scientists reseeding tissue-specific cells onto decellularized extracellular matrices derived from their tissue of origin should be aware that tissue-specific differentiation states should not be assumed to be constant," says Peter C. Johnson, MD, Vice President, Research and Development and Medical Affairs, Vancive Medical Technologies, and President and CEO, Scintellix, LLC, Raleigh, NC. "Appropriate testing of cellular markers after reseeding will be essential to characterize the true fate of replaced cells."
Mary Ann Liebert, Inc. Publishers News Release (05/18/15)
Abstract (Tissue Engineering Part A; Vol. 21, Issue 11-12, 1916-1928 (05/26/15))