[Perspectives and current state in limbal stem cell transplantation].

The transplantation of limbal stem cells is one of the most challenging surgical approaches in ocular surface reconstruction. Partial and unilateral limbal stem cell insufficiency (LSCI) can be treated by fractionated abrasion or autologous limbal stem cell transplantation from the fellow eye. In cases of advanced bilateral and partial LSCI, ex vivo expansion of limbal stem cells on amniotic membranes or fibrin can be performed but all patients with complete bilateral LSCI must rely on allogenic limbal stem cell transplantation with high immunological risks. Attempts to combine allogenic limbal stem cell transplantation with mitomycin C and amniotic membrane transplantation are promising. In the laboratory, attempts to transdifferentiate bone marrow stem cells into corneal epithelial cells have been without success. Nonetheless, transdifferentiation of hair follicle stem cells into corneal epithelial cells looks promising. In parallel, research on the limbal stem cell niche is ongoing to elucidate the natural environment of limbal stem cells in order to improve ex vivo culture.