The outer blood-retinal barrier (oBRB) is essential for preserving retinal homeostasis by controlling the exchange between the systemic circulation and retinal tissues. The oBRB consists of the retinal pigment epithelium cells (RPE) on one side and the choriocapillaries on the other with the Bruch’s membrane in between. In age-related macular degeneration (AMD) and hereditary choroidopathies the oBRB could be affected. These retinal diseases are characterized by progressive death of retinal cells, resulting in irreversible loss of sight. Currently, treatments are very limited.

Our project aims to develop a complex 3D oBRB model by deriving RPE and choroidal layer from human pluripotent stem cells (hPSCs) and culturing them on a biodegradable membrane. These membrane presents two geometrically different surfaces: 1- a smooth plane surface on which the RPE cells are able to generate a typical retinal epithelium; 2- a rough surface characterised by the presence of large pores to enhance endothelial cell penetration and vessels sprouting.

Using specific cell differentiation protocols, we have obtained a pure cell population of RPE, endothelial cells and pericytes derived from hPSCs. The cells are co-cultured on biodegradable membrane: the RPE cells on smooth plane surface and the endothelial cells and pericytes on opposite side. Microscopic analysis showed the presence of a typical RPE monolayer and colonization of pores of membrane by endothelial cells and pericytes.

To evaluate if this 3D cell culture can be used for cell therapy approach for retinal diseases it will be transplanted in a rat model.