The Current Status of Corneal Limbal Stem Cell Transplantation in Humans

Abstract

The cornea provides an accessible source of adult stem cells for cell-based therapies. Corneal stem cells have been discovered in the three primary strata—epithelium, stroma, and endothelium—of the cornea. Limbal epithelial stem cells are found on the surface and are able to differentiate into transient amplifying cells, which can regenerate epithelial tissues. Limbal stem cell deficiencies can result in epithelial defects, ulceration, corneal vascularization, chronic inflammation, scarring, and conjunctivalization of the cornea. Stromal stem cells share many properties with bone marrow-derived stem cells. Though stromal stem cell research is in the early stages, these cells may one day provide bio-prosthetic stromal material. Endothelial stem cells may be of particular importance due to endothelial cell damage during common surgeries and degenerative diseases. Current stem cell therapies focus on regeneration of the corneal surface by replacing limbal epithelial stem cells with corneal-derived cells, other adult stem cells or embryonic stem cells. Advances in cell culturing will hopefully soon be translated from bench to bedside to help in the treatment of severe ocular surface disease.