Sitagliptin and the Blood-Retina Barrier: Effects on Retinal Endothelial Cells Manifested Only after Prolonged Exposure

Figure 4

Tivozanib but not sitagliptin reverted the VEGF-A-induced barrier dysfunction of iBREC. Confluent monolayers of iBREC cultivated on gold electrodes were exposed to 50 ng/ml VEGF-A₁₆₅ () for one day before (a, c) 10 nM tivozanib or (b, c) 10-1000 nM sitagliptin was added (). The cell index (CI) was determined continuously as a measure of barrier function. In all experiments, CI values—presented as means and standard deviations from at least six wells—were normalized in relation to those measured immediately before addition of VEGF-A₁₆₅ (). Statistical analyses of data gained at indicated time points after addition of VEGF-A₁₆₅ were performed as described in Materials and Methods. (a, c) Inhibition of the VEGF receptor 2 completely reverted the VEGF-A₁₆₅-induced CI decrease. (b, c) Treatment with sitagliptin did not result even in partial reversion of the VEGF-A₁₆₅-caused CI reduction.

(a)

(b)

(c)