Limbal epithelial crypt: a model for corneal epithelial maintenance and novel limbal regional variations

Arch Ophthalmol. 2008 May;126(5):665-9. doi: 10.1001/archopht.126.5.665.

Abstract

Objective: To determine the distribution of cell membrane proteins and extracellular matrix proteins around the limbal epithelial crypt (LEC) compared with adjacent limbus and corneal epithelium.

Methods: Serial histological sections of human corneoscleral limbus rims were stained with antibodies of interest by standard immunohistochemistry.

Results: Superficial cells of the limbus were desmoglein 3 positive, compared with the negative basal cells of the limbus that correspond to cells with more stemlike properties. The LEC had a much lower proportion of desmoglein 3 staining in comparison. Tenascin C staining demonstrated regional variations of the limbus depending on their association with the LEC. Limbus that was associated with or adjacent to the LEC had a greater tenascin C expression compared with normal limbus, whereas the LEC demonstrated the greatest tenascin C expression.

Conclusions: Based on these and similar results previously reported for connexin 43, we propose a novel model on the mechanism of corneal surface epithelium maintenance involving 3 different limbal regions: zone 1, limbus including the LEC; zone 2, limbus associated with the LEC; and zone 3, limbus distant to the LEC.

Clinical relevance: The noted limbal variations may influence the selection of the donor site for limbal grafts in the future.

MeSH terms

  • Desmoglein 3 / metabolism
  • Epithelial Cells / cytology*
  • Epithelial Cells / metabolism
  • Epithelium, Corneal / cytology*
  • Epithelium, Corneal / physiology
  • Eye Proteins / metabolism
  • Fluorescent Antibody Technique, Indirect
  • Humans
  • Limbus Corneae / cytology*
  • Limbus Corneae / metabolism
  • Microscopy, Fluorescence
  • Models, Biological
  • Regeneration
  • Stem Cells / cytology*
  • Stem Cells / metabolism
  • Tenascin / metabolism

Substances

  • DSG3 protein, human
  • Desmoglein 3
  • Eye Proteins
  • Tenascin