Investigation on neural and ocular surface regeneration after cultivated mucosal epithelial sheet transplantation using amniotic membrane

应用角膜上皮干细胞和口腔粘膜上皮进行培养的粘膜上皮移植显著改善了严重眼表重建的临床效果。然而，细胞增殖和分化背后的生物学机制仍然不清楚。在这项研究中，使用体内激光共聚焦显微镜研究了由移植上皮组成的再生组织结构的体内条件。存活的口腔粘膜上皮显示出与角膜上皮相似的分化良好的复层上皮结构。高密度和大量的基底细胞表明细胞增殖的活跃潜力，以维持眼表。即使经过一段时间后，在上皮细胞层和羊膜下区域也没有观察到神经再生。口腔粘膜干细胞和祖细胞表达的p75与神经营养因子具有高亲和力，表明存活的口腔粘膜上皮细胞可能受神经生长因子（NGF）和神经营养因子3和4的调节。眼表面分化的口腔粘膜上皮不表达角蛋白1和4，角蛋白1和4是角化特异性的，但表达角蛋白3和13。存活的口腔粘膜上皮不表达角膜特异性的角蛋白12或杯状细胞特异性的MUCSAC。该研究得出结论，眼表面上存活的口腔粘膜上皮能够保留口腔粘膜上皮谱系而不转分化为眼表面上皮。

Cultivated mucosal epithelial transplantation using corneal epithelial stem cells and oral mucosal epithelium dramatically improves the clinical outcome of severe ocular surface reconstruction. However, the biological mechanisms behind the cell proliferation and differentiation still remain unclear. In this study, the in vivo condition of the regenerated tissue structure composed of transplanted epithelium was investigated using in vivo laser confocal microscopy. The surviving oral mucosal epithelium showed a well-differentiated, stratified epithelial structure similar to corneal epithelium. The high density and large number of basal cells indicated the active potential for cell proliferation to maintain the ocular surface. No neural regeneration was observed in the epithelial cell layer and sub-amniotic membrane region even after an extended period of time. This evidence is consistent with the low amount of ocular surface sensation.Oral mucosal stem- and progenitor cells expressed p75 that exhibited a high affinity with neurotrophin, indicating that surviving oral mucosal epithelium may be regulated by nerve growth factor (NGF) and neurotrophin 3 and 4. Differentiated oral mucosal epithelium on the ocular surface does not express keratin 1 and 4, keratins that are specific for keratinization, but does express keratin 3 and 13. Surviving oral mucosal epithelium does not express keratin 12 that is cornea specific or MUCSAC that is specific for goblet cells. This study concluded that surviving oral mucosal epithelium on the ocular surface is able to retain the oral mucosal epithelial lineage without transdifferentiation into ocular surface epithelium.