Identification and potential application of human corneal endothelial progenitor cells.

The corneal endothelium is believed to be developmentally originated from the periocular mesenchyme via the neural crest. Human corneal endothelial progenitor cells (HCEPs) have been investigated because of their potential availability for the tissue regenerative medicine. However, the existence and the properties of HCEPs have not been elucidated yet. We first established a novel serum-free culture system for HCEPs. The HCEPs highly expressed p75 neurotrophin receptor, SOX9, and FOXC2, and partially retained the properties of neural crest and periocular mesenchyme. Further, we demonstrated that HCEPs had a high proliferative potency, and the differentiated HCEP sheets had corneal endothelial function by using the Ussing chamber system and transplantation to the rabbit cornea. These findings suggest that the HCEPs can be selectively expanded from the corneal endothelium using a specific culture system and will provide cell sheets for corneal regenerative medicine.