Airway ciliated cells regenerated on collagen sponge implants acquire planar polarities towards nearby edges of implanted areas

Abstract

Summary Tissue‐engineered tracheae have been developed to replace defective tracheae. However, the direction of ciliated cells in the regenerated epithelium remains unclear. We investigated planar polarity formed in the regenerated airway epithelium after tracheal graft implantation. We partially resected the rat trachea and implanted a collagen scaffold. The direction of the basal foot was assessed by transmission electron microscopy. Immunofluorescence staining was performed to examine the biased distribution of Vangl1 and Frizzled6 proteins. The direction of mucociliary transport was analyzed by video microscopy. Our results showed that the basal feet of cilia in the proximal and distal regions of the implanted areas were respectively oriented toward the proximal and distal directions. The biased distribution of Vangl1 and Frizzled6, and the directions of mucociliary transport showed that planar polarities formed in the regenerated epithelium were oriented toward the proximal, distal, left, and right directions in the proximal, distal, left, and right regions of the implanted area. These polarities persisted until nine months after implantation. Hence, the results suggest that planar polarities formed in epithelia regenerated on tracheal grafts are directed toward the nearby edges of implanted areas and are preserved for a prolonged period. The polarities can, at least partially, contribute to clearing external materials from the implanted areas by transporting them to a normal region.

Development of novel layered polyglycolic acid sheet for regeneration of critical-size defect in rat trachea

“…Regarding the importance of the direction of ciliary movement, Thomas et al [13] reported that epithelial ultrastructural abnormalities may increase the risk of allograft colonization by pathogenic organisms despite a normal CBF, suggesting that not only the CBF but also the direction of ciliary movement (such as the CTF, which is the calculated speed of oral directional transport along the lung-oral axis) may be more important for preventing infection. Although there is currently no method to unify the movement of cilia, the regulation of planar cell polarity might be essential to unify the direction of the airway epithelial cilia [7,14,15].…”

“…We then examined the long-term survival after implantation of the novel PGA material and the morphological characteristics and functional performance of the novel PGA material. According to our previous studies, the sample size was set at 5 rats per observational period: 2 weeks, 1 month, 2 months and 6 months after implantation [7]. However, because 2 rats were needed for the morphological and functional evaluation, the total sample size was set at 40 rats.…”