Culture and characterization of oral mucosal epithelial cells on human amniotic membrane for ocular surface reconstruction

PURPOSE To culture oral mucosal epithelial cells on deepithelialized human amniotic membrane without the use of feeder cells and to compare the characteristics of cultured oral cells with cultured limbal and conjunctival epithelial cells for use in ocular surface reconstruction. METHODS Oral biopsies were obtained from healthy volunteers after informed consent and were cultured on deepithelialized amniotic membrane for three to four weeks. Confluent cultures of limbal, oral, and conjunctival cells were subjected to characterization of markers of stem cells and of epithelial differentiation by reverse-transcription polymerase chain reaction (RT-PCR) and by immunohistochemistry. Ultrastructural studies were also performed using electron microscopy. RESULTS A sheet of healthy, stratified oral epithelial cells was obtained within three to four weeks of culture. Electron microscopy demonstrated that the cells formed gap junctions and desmosomes. RT-PCR analysis showed that cultured oral epithelial cells expressed markers of epithelial differentiation such as cytokeratin K3, K4, K13, K15 and connexin 43. The cells also expressed stem cell markers of epithelial cells such as DeltaN isoforms of p63 as well as p75, a marker for stem cells of oral epithelium. The cells did not express cytokeratin K12 or Pax-6, an eye-specific transcription factor. CONCLUSIONS Oral epithelial cells can be cultured as explants on deepithelialized amniotic membrane without using feeder cells. Characterization showed that these cells maintain the phenotypic characteristics of oral epithelial cells and that the culture is a heterogeneous population of differentiated cells and stem cells. We find the cultured oral epithelial cells usable for ocular surface reconstruction in patients having bilateral ocular surface diseases.