Determination of the Culture Time Point to Induce Corneal Epithelial Differentiation in Induced Pluripotent Stem Cells.

BACKGROUND:Limbal stem cells (LSC) are progenitor cells in the ocular surface that renew the corneal epithelium. Limbal stem cell deficiency usually induces blindness through the loss of corneal transparency, and bilateral cases do not an accurate treatment because of the lack of an autologous source of stem cells. METHODS:Induced pluripotent stem cells (iPSC) are promising for use in cell therapy because of their autologous origin and the capability to differentiate into corneal epithelial cells. However, there are not standardized protocols to achieve a complete corneal epithelial differentiation. We examined the expression of several markers in a human episomal iPSC line after an induction period from embryoid bodies. RESULTS:Progenitor LSC and corneal epithelial differentiation markers, some extracellular matrix protein adhesion molecules, and wingless signaling pathway were studied. Overall, LSC progenitor and corneal epithelium differentiation markers increased after maintaining cell culture in specific conditions for 14 days, whereas pluripotency markers decreased. CONCLUSIONS:Our approach indicated that the optimal time point to initiate iPSC differentiation into LSC and corneal phenotypes, with the use of specific medium, is from 14 days after initial embryoid bodies treatment induction.