Roles of Transepithelial Electrical Resistance in Mechanisms of Retinal Pigment Epithelial Barrier and Retinal Disorders.

Transepithelial/transendothelial electrical resistance (TEER) is a widely accepted quantitative technique to measure the integrity of tight junction dynamics in cell culture models of endothelial and epithelial monolayers. The value of TEER reflects the physical structure and characteristics of epithelial/endothelial cells. TEER value is a preferred physiological indicator reflecting transport rate of ions and macromolecules through the paracellular pathway, which is used to evaluate permeability of paracellular pathway. TEER value has a high specificity for the permeability of reactive tightly connected complex. TEER value is an effective indicator to evaluate the integrity of cell barrier. The cell barrier not only controls the diffusion penetration of various substances in adjacent intercellular spaces, but also regulates the transport of ions and macromolecules across. On one hand, the cell barrier protects the body from harmful substances; on the other hand, it restricts the entry of therapeutic drugs. Therefore, with the increase of permeability in paraepithelial pathway, the TEER value decreased, otherwise, it increased. In this review article, we compared the advantages and disadvantages of the existing methods for measuring TEER and summarized the factors affecting TEER accuracy, as well as the roles of TEER in mechanisms of retinal pigment epithelial barrier and retinal disorders such as proliferative vitreoretinopathy (PVR), age-related macular degeneration (AMD), diabetic retinopathy, and retinitis pigmentosa.