Cell Sheets Promote Salivary Gland Regeneration

Objectives: Temperature-responsive polymer grafted culture dishes allow various types of cells to adhere and proliferate at 37°C. The cells spontaneously detach as a cell sheets when the temperature is reduced below 32°C without the need for proteolytic enzymes. Released cell sheets retain cell-cell communications, functional extracellular matrices and tissue-like behaviors. These features promote tissue regeneration and improve transplantation efficacy in various tissues. However, the functional effects of cell sheets for salivary gland regeneration to treat hyposalivation have not yet been studied. Therefore, the goal of this study was to determine whether cell sheets promote submandibular gland regeneration and restore secretory function in a wounded mouse model.
Methods: Mouse submandibular gland cells were isolated from 6 weeks old C57BL/6J female mice and harvested primary cells cultured on thermo-responsive cell culture dishes for 8 days. Then, cell sheets were transplanted into wounded mouse submandibular gland. After 8 days, glands were removed, sectioned, and stained for histopathological and morphometric analysis as well as with markers of salivary gland differentiation. Furthermore, quantity and quality of saliva were determined, as well as body weight changes.
Results: Cell sheets formed polarized structures that maintain cell-cell junctions and secretory granules in vitro. In addition, layered cell sheets formed a glandular-like pattern in vitro. Moreover, cell sheet transplanted mice showed new glandular tissue in wounded area, improved saliva secretion rates and quality of salivary protein patterns and, enhanced body weight to levels comparable to healthy controls.
Conclusions: Cell sheet transplantation promotes submandibular gland regeneration while improving functionality in a wounded mouse model and may offer a new therapeutic strategy for hyposalivation.