In five layers of cornea structure, endodermis located in the innermost layer has great significance on maintaining corneal transparency and normal corneal physiological function. Human Corneal Endothelial Cells (HCECs) regulate the transparency of cornea through pump function and barrier function. However, since adult corneal endothelial cells lack proliferation ability, its cytothesis mainly relies on cellular extension and migration of surrounding cells after damage. Corneal endothelial decompensation can be induced when the cell density is less than 500-800/mm2, leading to corneal edema and to losing transparency. Infection, inflammation, trauma, eye surgery and etc. may all induce endothelial cell damage, but due to the special physiological properties of human corneal endothelial cells, endothelial cell function recovery is often a difficult problem for eye disease treatment. The only effective way to treat corneal endothelial decompensation is to transplant corneal endothelial cells from a healthy donor and to replace the damaged or pathological changed cells by penetrating corneal transplantation or corneal endothelial transplantation. Given to worldwide extreme lack of available donor for corneal transplantation, and to postoperative immunological rejection, the application of corneal transplantation has been limited. Biological corneal transplantation can effectively relieve the pressure of natural corneal materials and has great value socially and economically. However, it demands sufficient supply of corneal endothelial cells for the purpose of the construction of biological corneal endothelial as well as merely endothelial cells transplantation. Due to limited proliferative capacity of adult corneal endothelial cells as well as the limited ability of external culture amplification, to find new endothelial cells is an urgent problem to be solved. It is extremely urgent to obtain a large number of functional coneal endothelial cells similar to normal human to meet the needs for cytobiology research and cell replacement therapy.
At present, research on the inducting differentiation of corneal endothelial cells is still in its early stage. Researchers earlier have tried to replace non-proliferable corneal endothelial cells with adipose skin cells or mesenchymal stem cells or tried to induce differentiation of embryonic stem cells, stromal stem cells, bone marrow endothelial progenitor cells or neural crest cells into corneal endothelial cells, but these methods all exist some problems, such as immune rejection, ethical issues, poor histocompatibility and lack of animal experiments, etc. A method for achieving a large number of functional corneal endothelial cells in vitro has not been found yet.