title: Limbal and corneal epithelial homeostasis.
abstract: OBJECTIVE
  The aim of this review is to describe the underlying mechanisms of corneal epithelial homeostasis in addition to illustrating the vital role of the limbal epithelial stem cells (LESCs) and the limbal niche in epithelial regeneration and wound healing.
  
  
  RESULTS
  The shedded corneal epithelial cells are constantly replenished by the LESCs which give rise to epithelial cells that proliferate, differentiate, and migrate centripetally. While some recent studies have proposed that epithelial stem cells may also be present in the central cornea, the predominant location for the stem cells is the limbus. The limbal niche is the specialized microenvironment consisting of cells, extracellular matrix, and signaling molecules that are essential for the function of LESCs. Disturbances to limbal niche can result in LESC dysfunction; therefore, limbal stem cell deficiency should also be considered a limbal niche deficiency. Current and in-development therapeutic strategies are aimed at restoring the limbal niche, by medical and/or surgical treatments, administration of trophic factors, and cell based therapies.
  
  
  CONCLUSIONS
  The corneal epithelium is constantly replenished by LESCs that are housed within the limbal niche. The limbal niche is the primary determinant of the LESC function and novel therapeutic approaches should be focused on regeneration of this microenvironment.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA.
authors.forename: Ghasem
authors.initials: G
authors.lastname: Yazdanpanah
authors.forename: Sayena
authors.initials: S
authors.lastname: Jabbehdari
authors.forename: Ali R
authors.initials: AR
authors.lastname: Djalilian
mesh_terms: D002454:Cell Differentiation; D049109:Cell Proliferation; D003316:Corneal Diseases / Q000503:physiopathology; D004847:Epithelial Cells / Q000502:physiology*; D019573:Epithelium, Corneal / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D016850:Limbus Corneae / Q000502:physiology*; D013234:Stem Cells / Q000502:physiology*; D014945:Wound Healing / Q000502:physiology*