Tissue engineering by transplantation of oral epithelial sheets cultivated on amniotic membrane for oral mucosal reconstruction

Human amniotic membrane (AM), a thin intrauterine placental membrane is highly biocompatible, and possesses anti-inflammatory and anti-scarring properties. Using AM, we developed a novel method for cultivating oral mucosal epithelial cell sheets. We evaluated autologous transplantation of oral mucosal epithelial cells on AM in patients undergoing oral surgeries. Specimens of AM were obtained from women undergoing Caesarean section. Using oral mucosal biopsy specimens obtained from the patients, oral epithelial cells were cultivated on an AM carrier. The resultant sheet was transplanted on the oral mucosal defect. After 2-3 weeks of culture, the cultivated epithelial cells seemed well differentiated and showed stratification into 5-7 layers on AM. Immunohistochemistry demonstrated that the cultivated cells expressed highly specific mucosal epithelial cell markers and basement membrane proteins. After the surgical procedure, the reconstructed sites did not show infection, bleeding, rejection, or sheet detachment, and the sites achieved a new oral mucous membrane. The cultivated epithelial sheets maintained the properties of a mucous membrane and expressed basement membrane proteins. Autologous transplantation of cultivated oral epithelial sheets was performed, and the transplanted tissue showed adherence to the oral mucosal defect. A long-term follow-up of more than 12 months revealed absence of postoperative recurrence, and the postoperative courses were excellent. These findings showed that this novel epithelial sheet is a useful biomaterial for mucosal reconstruction.