Clinical and histopathological analysis of healing process of intraoral reconstruction with ex vivo produced oral mucosa equivalent.

We fabricated ex vivo produced oral mucosa equivalent (EVPOME) from patients' oral mucosal keratinocytes without using animal-derived serum or feeder layer cells. To confirm the clinical benefits of 1) early initiation of epithelialization, 2) a short period until complete healing and 3) negligible scar contracture, the mechanism of wound healing after EVPOME transplantation for oral mucosal defects was analyzed histopathologically. Transplantation was performed on 15 patients (eight men and seven women; aged between 51 and 76 years, mean, 66.6 years). Two patients had squamous cell carcinoma of the tongue, nine had leukoplakia (four in the tongue only, two in the gingiva only, one in the buccal mucosa, and two in two or more areas), and four had hypoplasia in the alveolar ridge. The mean interval between punch-biopsy for the fabrication of EVPOME and its transplantation for the reconstruction of oral mucosal defects was 28.5 days, by which time EVPOME with a mean size of 6.5 cm(2) and a cell count of 8.6 x 10 5-plex th; could be obtained. The underlying disease, past history, and smoking history of the patients did not constitute negative factors for EVPOME fabrication. About 10 days after transplantation, EVPOME began uniting with the surrounding epithelium. The mean duration required for the wound to be completely covered (28.2 days) was much shorter than after transplantation of only an acellular allogenic dermal matrix (AlloDerm), and showed only slight scar formation, similar to that observed after artificial dermis (Terdermis) transplantation. Presence of laminin-1, 5 and type IV collagen in the basement membrane of EVPOME was confirmed, and the arrangement and positioning of keratinocytes were preserved during the degradation of perlecan and anchoring fibrils (type VII collagen) for remodeling, i.e., the period of the most active remodeling of EVPOME transplantation. Only a few fibroblasts were observed in the lamina propria during this period, suggesting that keratinocyte-derived cytokines, rather than fibroblast-derived cytokines, play an important role in the early stages of mucosal wound healing after EVPOME transplantation. The efficacy of EVPOME is associated with closely related to the presence of the keratinocyte-derived system and the usefulness of AlloDerm that sustains keratinocytes.