title: Limbal epithelial crypt: a model for corneal epithelial maintenance and novel limbal regional variations.
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.
  
  
  CONCLUSIONS
  The noted limbal variations may influence the selection of the donor site for limbal grafts in the future.
authors.affiliation: Division of Ophthalmology and Visual Sciences, University of Nottingham, Nottingham, England.
authors.forename: Aaron Ming-Hon
authors.initials: AM
authors.lastname: Yeung
authors.forename: Ursula
authors.initials: U
authors.lastname: Schlötzer-Schrehardt
authors.forename: Bina
authors.initials: B
authors.lastname: Kulkarni
authors.forename: Naing L
authors.initials: NL
authors.lastname: Tint
authors.forename: Andrew
authors.initials: A
authors.lastname: Hopkinson
authors.forename: Harminder S
authors.initials: HS
authors.lastname: Dua
mesh_terms: D051184:Desmoglein 3 / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism; D019573:Epithelium, Corneal / Q000166:cytology* / Q000502:physiology; D005136:Eye Proteins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D016850:Limbus Corneae / Q000166:cytology* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D012038:Regeneration; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D019063:Tenascin / Q000378:metabolism
chemical_list: C071894:DSG3 protein, human; D051184:Desmoglein 3; D005136:Eye Proteins; D019063:Tenascin