Current concepts and challenges in ocular surface reconstruction using cultivated mucosal epithelial transplantation

Ocular surface disorders wherein corneal stem cells are deficient result in total conjunctivalization leading to severe visual dysfunction and blindness. Treatment of these diseases requires reconstruction of the ocular surface using epithelial transplantation to provide a smooth refractive corneal surface and biologic and physical barriers against a variety of destructive factors. Recently, regenerative medicine focusing on tissue-engineered techniques has been developed and established as a new clinical field. In particular, cultivated mucosal epithelial transplantation using well-differentiated, stratified epithelial sheets on amniotic membrane allows a rapid re-epithelial cover over the entire corneal surface, resulting in early reduction of inflammation and cicatrization. This surgical approach dramatically improves the prognosis of severe ocular surface diseases, especially severely inflamed corneal stem cell deficiency. This new approach not only provides early epithelialization but also allows reconstruction of the corneal surface using autologous cultivated epithelium including the cornea and oral mucosa from a small number of cell sources after amplification. Tissue-engineered strategies using autologous corneal or oral mucosal epithelial sheet transplantation avoid the risk of rejection and complications associated with immunosuppressive treatments. In addition to new cellular transplantation, combined automated lamellar therapeutic keratoplasty provides better refractive stromal interference and contributes to performance and safety of cataract surgery in severe corneal opacity cases. Although long-term prognosis and cell biologic behavior of tissue-engineered epithelium after transplantation should be carefully monitored, these recent surgical treatments have opened a new field for ocular surface reconstruction.