title: Keratinocytes of tissue-engineered human oral mucosa promote re-epithelialization after intraoral grafting in athymic mice.
abstract: OBJECTIVE
  The objective of this study was to investigate the role of grafted oral keratinocytes in a transplanted ex vivo-produced oral mucosa equivalent (EVPOME) in the regeneration and/or healing process of the oral mucosa at the recipient site.
  
  
  METHODS
  The EVPOME was developed in a serum-free defined culture system without a feeder layer. EVPOME is composed of a stratified layer of human oral keratinocytes that are seeded onto a human cadaveric dermis, AlloDerm (LifeCell, Branchburg, NJ). Intraorally grafted EVPOMEs in athymic mice (BALB/c) were excised, contiguous with the surrounding oral mucosa, on days 5, 7, 14, and 21 after grafting. Serial sections were stained with hematoxylin-eosin and immunohistochemically analyzed for cytokeratin 17 (CK17) expression to distinguish the human-cultured EVPOME epithelial keratinocytes from murine oral keratinocytes.
  
  
  RESULTS
  All EVPOME epithelial cells showed intense immunoreactivity for CK17, whereas mouse buccal mucosal epithelial cells did not show CK17 immunoreactivity. The grafted EVPOME maintained a stratified epithelial layer for up to 5 days after grafting. By day 7 after grafting, a portion of the EVPOME epithelial layer peeled away from the AlloDerm, and a thin, CK17-immunonegative epithelial layer extended from the adjacent thick epithelial layer of the mouse and contacted the CK17-immunopositive EVPOME epithelium. From days 14 to 21 after grafting, the stratification of the CK17-immunonegative continuous mouse epithelium increased compared with earlier time points and showed a similar appearance to the epithelium of the adjacent mouse mucosa. In contrast, no epithelial coverage of the AlloDerm that was grafted without keratinocytes was observed for up to 21 days after grafting. The grafted AlloDerm without cells resulted in tissue necrosis that was accompanied by a dramatic infiltration of inflammatory cells by day 14.
  
  
  CONCLUSIONS
  These findings suggest that grafting of EVPOME with viable oral keratinocytes onto an intraoral mucosal wound plays an active role in promotion of re-epithelialization of the oral wound during the subsequent healing process.
authors.affiliation: Division of Reconstructive Surgery for Oral and Maxillofacial Region, Department of Tissue Regeneration and Reconstruction, Course for Oral Life Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. yoshi@dent.niigata-u.ac.jp
authors.forename: Michiko
authors.initials: M
authors.lastname: Yoshizawa
authors.forename: Takahiro
authors.initials: T
authors.lastname: Koyama
authors.forename: Taku
authors.initials: T
authors.lastname: Kojima
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kato
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Ono
authors.forename: Chikara
authors.initials: C
authors.lastname: Saito
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D018929:Cell Culture Techniques; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry; D004129:Dimethylpolysiloxanes; D004847:Epithelial Cells / Q000502:physiology; D005881:Gingiva / Q000166:cytology; D006801:Humans; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D053537:Keratin-17 / Q000032:analysis; D015603:Keratinocytes / Q000502:physiology* / Q000637:transplantation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009059:Mouth Diseases / Q000601:surgery; D009061:Mouth Mucosa / Q000166:cytology* / Q000601:surgery; D009336:Necrosis; D009779:Occlusive Dressings; D012038:Regeneration / Q000502:physiology; D013997:Time Factors; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry; D014945:Wound Healing / Q000502:physiology
chemical_list: C440568:Alloderm; D001672:Biocompatible Materials; D004129:Dimethylpolysiloxanes; D053537:Keratin-17; C013830:baysilon; D003094:Collagen