Transepithelial electrical resistance

Cell cultures. MDCK cells were seeded in the Transwells at a density of 2.2 x 104 cells/cm. Cells were fed by changing medium in both upper (apical) and lower (basal) compartments periodically. Confluent monolayers were obtained at 5-7 days post-inoculation, when the cell density reached 4.5-5.0 x 105 cells/cm2, and a transepithelial electrical resistance (TEER) of about 2,000 ohms cm2 was measured using an epithelial voltohmmeter (EVOM, World Precision Instruments, West Haven, CT). The amount of FBS in the cell culture medium could be decreased as the cells approached their maximum resistance, and could be maintained at that point for 2 days or longer in medium containing 1% FBS. 

The in vitro system we have been using to study the transepithelial transport is cultured Madin-Darby canine kidney (MDCK) epithelial cells (11). When cultured on microporous polycarbonate filters (Transwell, Costar, Cambridge, MA), MDCK cells will develop into monolayers mimicking the mucosal epithelium (11). When these cells reach confluence, tight junctions will be established between the cells, and free diffusion of solutes across the cell monolayer will be markedly inhibited. Tight junction formation can be monitored by measuring the transepithelial electrical resistance (TEER) across the cell monolayers. In Figure 1, MDCK cells were seeded at 2 X 104 cells per well in Transwells (0.4 p pore size) as described previously. TEER and 14C-sucrose transport were measured daily. To determine 14C-sucrose... 

Figure 1. The correlation of transepithelial electrical resistance (TEER) with the transepithelial transport of 14C-sucrose in MDCK cell monolayers grown on microporous filters.

Figure 14 Observed permeability coefficients of urea and mannitol across monolayers of rat alveolar epithelial cells in primary culture in the Transwell system are correlated with transepithelial electrical resistance and days in culture.

Figure 15 An increase in transepithelial electrical resistance (TER) of MDCK cell monolayers with time in culture reflects the gradual formation of a continuous sheet of epithelia with restrictive tight junctions. [Redrawn from Cho et al. (1989) with permission from the publisher.]...

Figure 16 Correlation of effective pore radius of the paracellular route of rat alveolar epithelial cell monolayers with transepithelial electrical resistance and time in culture. Pore radii were calculated from the data shown in Figure 14.

Evaluation of the epithelial integrity can be performed by measuring the transepithelial electrical resistance (TEER). TEER values ranging from 150 ohms.cm2 up to 600 ohms.cm2 have been reported. An alternative method for assessing the monolayer integrity is to monitor the flux of hydrophilic marker molecules that pass the monolayers by the paracellular route (e.g., mannitol, Na-fluorescein, or atenolol). 

Figure 9.1 Relationship between the transepithelial electrical resistance (TEER) value of the passage-cultured human nasal epithelial cell layer and permeability of 14C-mannitol (o, passage-2 A, passage-3 , passage-4) and budesonide ( , passage-2 , passage-3 , passage-4). (Data from Ref. [40]).

Figure 9.3 Changes in transepithelial electrical resistance (TEER) of human nasal epithelial cell layers grown under LCC ( ) versus AIC (A) conditions. Each data point represents the mean SD of three determinations. (Data from Ref. [46]).

Baida MS, Whitney JA, Flores C, Gonzalez-Mariscal L, Cereijido M, and Matter K [1996] Functional dissociation of paracellular permeability and transepithelial electrical resistance and disruption of the apical-basolateral intramembrane diffusion barrier by the expression of a mutant tight junction membrane protein. J Cell Biol 134 1031-1049... 

TEER Transepithelial electrical resistance TEM Transmission electron microscopy... 

Lecluyse EL, Sutton SC, Fix JA. In vitro effects of long-chain acylcamitines on the permeability, transepithelial electrical resistance and morphology of rat colonic mucosa. J Pharmacol Exp Ther 1993 265 955-962. 

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