Table 3.

Overview of the RPE cell model properties.

Cell Model	Culture Conditions	Tight Junction Protein Expression	Pigmentation	Barrier Properties: Conclusions of this Study	Assays in Which the Cell Model can be Utilized in Early Drug Discovery
Cell lines
ARPE19	simple to demanding; variation between laboratories	yes	no	leaky	Drug uptake, active transport
ARPE19mel	simple	yes	can be controlled; from low to heavy	leaky	Drug uptake: quantitative effects of pigmentation
LEPI	simple	yes	no	tight	Drug uptake and permeation
Primary RPE cells
hfRPE	simple	yes	low/modest	leaky	Drug uptake, active transport
Stem-cell based RPE cells
hESC-RPE	demanding; long differentiation time, requires specialized conditions and expensive supplements	yes	heavy	tight	Drug uptake and permeation