Engineered human oral mucosa for in vivo gingival regeneration

Oral mucosa deficits are usually corrected with autologous tissue from either the soft or hard palates. Considered as the gold standard in damaged tissue reconstruction, this procedure is hampered by significant limitations. To overcome these limitations, some clinical initiatives have shown the possible use of engineered oral mucosa for tissue reconstruction. Objectives: The aim of this study was to engineer a human oral mucosa and evaluate the tissue structure when grafted onto an animal model. Methods: Normal human epithelial cells and fibroblasts were isolated from gingival biopsies. Cells we propagated then used to engineer human oral mucosa using a collagen scaffold. Before grafting, tissue structure and protein production were investigated using histological and immunohistochemical techniques. The in vivo studies were performed by grafting the engineered tissue onto the dorsa of immunodeficient mice. After 15 and 60 days post grafting, biopsies were collected and used to evaluate the structure of the newly generated mucosa. Results: In vitro study showed that gingival cells were able to adhere and proliferate when seeded into collagen scaffold. Epithelial cells gave a well-structured and stratified epithelium, basically when cultured onto connective tissue (collagen matrix populated with gingival fibroblasts). Following grafting, engineered human oral mucosa was able to generate mucosa that covers all available grafting surface. The tissue contained a well-vascularised lamina propria and well-structured epithelium. This epithelium showed stratified layers of epithelial cells expression keratins such as Ki67 and K14. Both structures communicate through a basement membrane containing lamini-5 and type IV collagen. Conclusion: All together, the results demonstrate the usefulness of engineered oral mucosa tissue as an alternative to replace damaged gingiva (Funded by the FODQ and the FRSQ/RSBO).