Fig. 2.

Dose-dependent effect of Aβ_1-40 aggregation mixtures on endothelial permeability and TEER in HBMVECs. (a) HBMVEC monolayers grown to confluence on 6.5 mm diameter polycarbonate membrane inserts (0.4 μm pore size) were stimulated via 24 h incubation. Confluent HBMVEC monolayers were incubated with 0, 0.1, 0.3, 1.0, 3.0, 5.0, or 10.0 μmol/L unpurified Aβ_1-40 reaction mixture (R_H = 65 nm). Values of P_e were calculated as in Fig. 1, and Relative P_e was determined as the ratio of the P_e observed following Aβ_1-40 activation to the P_e observed for untreated monolayers. Dependence of Relative P_e upon Aβ_1-40 concentration was significant (P < 0.005). Results are representative of at least three independent experiments, performed with three repetitions. Error bars represent SEM. (b) HBMVEC monolayers were grown on 6.5 mm diameter polycarbonate membrane inserts (0.4 μm pore size) in the presence of 550 nmol/L hydrocortisone, and TEER was measured following 0, 1, 2, 3, 4, 5, 6 and 7 days of growth as confluence was reached. At day 7 (arrow), confluent monolayers were incubated alone (○), with 10 Units TNF-α (●), or with 2.5 μmol/L ( ), 5.0 μmol/L ( ), or 10 μmol/L ( ) unpurified Aβ_1-40 reaction mixture. TEER was measured following 1, 2, 3, 4, 5, 6, and 7 days of incubation. Results are representative of at least three independent experiments in which TEER measurements were performed with three repetitions. Error bars represent SEM. Some error bars lie within symbols.