Effects of hyperglycemic conditions and cigarette smoke extract exposure on hCMEC/D3 cell viability. Lactate dehydrogenase (LDH) release, a measure of cytotoxicity from the D3 cell monolayers at 12 h (a) and 24 h (b) following exposure to HG, CSE and HG + CSE conditions vs. controls. Data are expressed as mean ± SD (% control). Phase contrast microscopic images (10×, scale 400 µm) of the hCMEC/D3 monolayers clearly showed a lack of cell toxicity under the experimental conditions tested above. n = 3 biological replicates.