Preservation of CHIR-99021 cost corneal transparency is essential for vision. This requires integrity of the three layers of the cornea, the stratified squamous epithelium, the stroma and the inner surface endothelium. The corneal endothelium is a monolayer of cells, which is formed from neural crest-derived cells. During development, corneal endothelial cells proliferate and migrate centrally to form a continuous mosaic of cells, facing the aqueous humor. Cellcell contact induces growth arrest in G1 phase through contact inhibition mechanism, leading to the formation of a monolayer with a defined endothelial cell density. The corneal endothelium is responsible for the passive diffusion of nutriments from the aqueous humor and for the hydration of the cornea through its barrier and ionic pump functions. Several studies have shown that human endothelial cells do not replicate in vivo, even if they retain a proliferative potential, as seen in ex vivo wound healing experiment or in vitro. A recent study demonstrated that a few proliferating cells were found exclusively in extreme periphery of endothelium on human corneas with a short postmortem time and that a very slow and continuous centripetal cell migration might exist to partially compensate the physiological cell loss in vivo. Nevertheless, this mechanism cannot immediately compensate neither acute nor chronic important CEC losses which are replaced by enlargement and migration of neighboring cells resulting in shape modification and increase of cell size. In physiologic conditions the insufficient proliferative buy 905579-51-3 capacity leads to a gradual ECD decrease of per year. This decrease can be accelerated as a result of accidental trauma, certain systemic diseases like diabetes, treatment for glaucoma or endothelial dystrophies. When ECD falls below a critical threshold, the barrier and pump functions of the endothelium are compromised and this results in the formation of a corneal oedema and loss of visual acuity. The conventional treatment for such severe disorder is corneal transplantation, including penetrating keratoplasty and endothelial lamellar graft. Human corneas harvesting, evaluation, preservation and distribution are under the responsibility of eye bank
