Generation of hESC-derived retinal pigment epithelium on biopolymer coated polyimide membranes.

The in vitro generation of a functional retinal pigment epithelium (RPE) for therapeutic applications requires a limitless source of RPE cells and a supporting scaffold, which improves cell survival and promotes the acquisition of the RPE phenotype. We successfully differentiated human embryonic stem cells (hESCs) toward RPE on a transplantable, biopolymer coated polyimide (PI) membrane. We studied various membrane coatings of which several lead to the generation of a tight and highly polarized epithelium having typical characteristics and functions of human RPE. The cells established a distinctive hexagonal, cobblestone morphology with strong pigmentation, expressed RPE specific genes and proteins, and phagocytosed photoreceptor outer segments (POS) after co-culture with rat retinal explants. The barrier function of hESC-derived RPE (hESC-RPE) monolayers was confirmed by transepithelial electrical resistance and permeability measurements. In conclusion, we show that the PI biomembrane is a suitable scaffold for hESC-RPE tissue engineering.