Limbal Stem-Cell Expansion and Transplantation

Limbal stem-cell transplantation is indicated for treating a corneal epithelial stem-cell disorder known as limbal stem-cell deficiency (LSCD). Lamellar and/or penetrating keratoplasty cannot be used successfully in these cases as donor corneal epithelium is replaced by that of the recipient within months. In the presence of corneal epithelial stem-cell compartment deficiency, donor graft reepithelialization will not take place, with subsequent epithelial defects and the ultimate recurrence of conjunctivalization and the risk of rejection and failure. Unilateral limbal stem-cell deficiency has been successfully treated for years by directly grafting a portion of the healthy limbal tissue taken from the contralateral eye, but some concerns exist regarding potential donor eye risks. To overcome risks for the donor eye, a technique to reduce biopsy dimension using cell expansion in culture has been developed. Autologous cultivated limbal stem-cell transplantation is an effective and safe procedure to treat limbal stem-cell deficiency when there is an undamaged, even small, portion of the limbus that will provide donor cells to be expanded in vitro. Ex vivo limbal grafts have several advantages compared with the previously used technique of directly grafting limbal tissue, including fewer risks for the donor eye, possibility to treat bilateral LSCD, and possibility of regraft after failure. Unilateral and partial bilateral limbal deficiency can thus be successfully treated with long-term survival and without the need for systemic immunosuppression.