Year: 2010
Type: dissertation
Abstract: The posterior location and the blood-retinal barrier (BRB) make drug delivery in diseases affecting retina and vitreous challenging.The outer part of BRB is composed of retinal pigment epithelium (RPE), which restricts drug entry to the retina from the systemic circulation and from the periocular space.In this study, filter grown ARPE-19 cells have been characterized as a potential in vitro model of the human RPE for use in drug delivery studies.ARPE-19 barrier properties were evaluated in different culture conditions.The ARPE-19 model was 3-17 times more permeable than isolated bovine RPE-choroid tissue, but the ARPE-19 model efficiently separated test compounds based on their lipophilicity and molecular sizes.Expression of RPE related genes, RPE65, CRALBP, TRP1, tyrosinase and Mitf-A and OTX2 transcription factors was greatly enhanced by filter culture.It has become evident that transporters play an important role in pharmacokinetics.The expression of efflux proteins, p-glycoprotein (P-gp), multidrug resistance associated proteins 1-6 (MRP) and breast cancer related protein (BCRP), in various RPE cell lines was studied.As with primary RPE cells, ARPE-19 cells express MRP1, MRP4 and MRP5 efflux proteins.Efflux protein activity was evaluated in cellular uptake studies using calcein-AM and carboxydichorofluorescein as probe molecules, and by bi-directional permeability studies.The studies indicate MRP1 and MRP5 activity in ARPE-19 cell line.Active transport in the ARPE-19 cell model was qualitatively, though not quantitatively similar, with isolated RPE-choroid tissue.Furthermore, non-viral gene transfer was studied in the ARPE-19 cell model.Prolonged gene expression was achieved by liposomal carriers.In conclusion, the ARPE-19 cell model can be used to screen drug molecules with different physicochemical properties and in gene delivery studies.The greater passive permeability may lead to an underestimation of active transport in this model.Several membrane transporters are expressed and active in the ARPE-19 cell model.
Author: Eliisa Mannermaa
Language: English
Subfield: Ophthalmology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W3096146625