gms | German Medical Science

One of the major hallmarks of age-related macular degeneration (AMD) is the accumulation of protein-lipid deposits, known as ‘drusen’, in the tissues of the outer blood-retinal barrier (BRB). The key cells within the BRB are the retinal pigment epithelium (RPE) and the endothelial cells (ECs) forming the choroidal capillaries. The recent development of human-induced pluripotent stem cell (hiPSC)-derived RPE and ECs has led to their use as in vitro models in drug development. However, such models typically rely on simplified monolayer cultures that insufficiently capture the tissue dysfunction of AMD. In order to overcome this limitation, microfluidic organ-on-chip technology represents a promising technology for the development of 3D in vitro models. These microfluidic cell culture devices have engineered microchannels that are continuously perfused and inhabited by living cells to form tissues that exhibit organ-level physiology. The aim of this project is therefore to develop an organ-on-chip model of the outer BRB, fully based on hiPSC-derived cells. We are currently generating ECs and RPE from hiPSC lines obtained from control and AMD-affected individuals. All individuals were genotyped for 52 AMD-associated variants, and 13 AMD-related genes were sequenced to detect rare coding variants. Differentiation and maturation of hiPSCs-derived cells is assessed using immunostaining of several markers specific to each cell type. Characterized cells are then incorporated into an organ-on a-chip device containing a microchannel and an open top culture chamber, separated by a polyester membrane. ECs are seeded in the microchannel in order to mimic a capillary-like structure, and RPE cells are seeded in the open top culture chamber. For both cell types survival and maturation in their respective microenvironment is assessed. This new in vitro model will provide new knowledge on how various molecular, cellular and physical aspects interact in AMD, and can be used for testing new therapeutic molecules.