Fig. 1.

Anti-PECAM/catalase conjugates protect against endothelial barrier dysfunction induced by H₂O₂ insult. A, TEER across HUVEC monolayers was used to evaluate endothelial permeability. HUVEC monolayers grown onto Transwell inserts (3.0-μm pore size) were transferred to Endohm (World Precision Instruments) chambers for resistance measurement at different time points. At the arrow-indicated time point, the cells were stimulated with H₂O₂ (400 μM). The recorded values were normalized to the initial resistances of the monolayers before H₂O₂ treatment. The normalized TEER values are represented as means ± S.D. (n = 3). B, Ab/catalase treatment (1 and 10 μg/ml) abolished H₂O₂-induced endothelial hyperpermeability. HUVEC monolayers were preincubated with conjugates for 30 min and washed three times to remove unbound conjugates. Cells then were stimulated with H₂O₂ (400 μM) and subjected to TEER measurement. C, mixture of PEGylated SOD and catalase (10 μg/ml of each) failed to attenuate H₂O₂-induced TEER decline.