Evaluation of the selected barrier properties of retinal pigment epithelial cell line ARPE-19 for an in-vitro blood-brain barrier model

Abstract

In-vitro models that maintain complex transport mechanisms and structural properties associated with the blood-brain barrier in vivo would be useful in drug permeability and neurotoxicological studies. To evaluate the suitability of a human retinal pigment epithelial cell line for a blood-brain barrier model, we have compared the barrier properties of the human retinal pigment epithelial cell line ARPE-19, the human colonic adenocarcinoma cell line Caco-2, and primary porcine microvessel endothelial cells. The tight junction proteins occludin and ZO-1 were stained immunocytochemically. The paracellular ionic permeability was evaluated by measuring the trans-epithelial or trans-endothelial electric resistance. To evaluate the active transport mechanisms, the existence and the activity of the efflux transporters, P-glycoprotein and multidrug resistance-associated proteins, were studied. All the cell types in this study stained positively for occludin and ZO-1. However, the trans-endothelial electric resistance of ARPE-19 cells was low compared with that of primary porcine microvessel endothelial cell and Caco-2 cells. In addition, both the P-glycoprotein expression and its activity in ARPE-19 cells were low. In conclusion, the barrier properties of the human ARPE-19 cell line were not satisfactory for a blood-brain barrier model. For future studies, it is important to develop a human brain endothelial cell line with expression of the complex in-vivo properties of the blood-brain barrier.