Altered glycaemia affects BBB integrity. Hypoglycemia induced a significant increase in extracellular VEGF release from hCMEC/D3 monocultures at 24 h (A). Both, hyper and hypoglycemic exposure significantly up-regulate 24 h VEGF release from hCMEC/D3 cells co-cultured with astrocytes (B). Hyper and hypoglycemia affect BBB integrity as demonstrated by TEER (ohm.cm2) measurement over 72 h exposure. TEER values of cell-free inserts served as a reference (C). Also shown in figure were the TEER values during initial set up prior to treatment. Increase in paracellular permeability of fluorescent dextrans (4-70 kDa) expressed as percentage of control by hyper and hypoglycemia, across the monolayers of hCMEC/D3 cells (apical or luminal side) co-cultured with astrocytes (abluminal side), at 30 min following the addition of dextrans (D). Briefly, hCMEC/D3 cells in Transwell inserts were exposed to altered glycemic conditions for 30 min at 37°C, prior to addition of labeled dextrans. Data were expressed as mean ± S.E.M. *** p < 0.001, ** p < 0.01, * p < 0.05 and # p < 0.05, vs. control. N = 5-6/condition and replicated twice.