Cornea Cultivated Cornell
Cultivated Cornell And Conjunctival Stem Cell Grafting For Surface Disorders
We have analyzed the proliferative and differentiation potential of human ocular keratinocytes. Holoclones, meroclones, and paraclones, previously identified in skin, constitute also the proliferative compartment of the ocular epithelium. Ocular holoclones have the expected properties of stem cells, while transient amplifying cells have variable proliferative potential. Corneal stem cells are segregated in the limbus, while conjunctival stem cells are uniformly distributed in bulbar and forniceal conjunctiva. Conjunctival keratinocytes and goblet cells derive from a common bipotent progenitor. Goblet cells were found in cultures of transient amplifying cells, suggesting that commitment for goblet cell differentiation can occur late in the life of a single conjunctival clone. We found that conjunctival keratinocytes with high proliferative capacity give rise to goblet cells at least twice in their life and, more importantly, at rather precise times of their life history, namely at 45-50 cell doublings and at approximately 15 cell doublings before senescence. Thus, the decision of conjunctival keratinocytes to differentiate into goblet cells appears to be dependent upon an intrinsic "cell doubling clock. " These data open new perspectives in the surgical treatment of severe defects of the anterior ocular surface with autologous cultured conjunctival epithelium.
The ocular surface. This figure shows areas of the ocular surface from where biopsies were taken. Fornix, limbus, and paracentral cornea are colored in yellow, red, and blue, respectively. The central cornea is indicated by the asterisk. The bulbar region is indicated by the white color. Biopsies were taken from: superior.
- (a) inferior
- (b) fornix superior
- (c) temporal
- (d) inferior
- (e) and nasal
- (f) bulbar conjunctiva superior
- (g) temporal
- (h) inferior
- (i) and nasal
- (l) limbus paracentral
- (m) central
- (n) cornea
