Figure 2. Vascular endothelial growth factor (VEGF) and retinal pigment epithelium (RPE) transcription factor expression during RPE in vitro maturation. qRT–PCR analysis was performed on cDNA isolated from human retinal pigment epithelium (ARPE-19) cells that were maximally differentiated for 6 weeks and cells cultured on plastic that were 70% or 100% confluent. (A) VEGF and (B) RPE-transcription factors were upregulated in polarized ARPE-19 cells compared to non-polarized cells cultured on plastic. The experiment was performed in triplicate, and the results are expressed as the mean±standard deviation.