Figure 4. Increased expression of genes in cholesterol and lipid pathways SFM is blocked by supplementation with LDL. Quantitative PCR (qPCR) measures of gene expression from serum-free medium (SFM) ARPE-19 cultures without and with added low-density lipoprotein (LDL; 50 µg/ml) compared to day 0 serum-supplemented cultures. Relative quantity (RQ) values were calculated using the –ΔΔC_t method and normalized using the mean value of four reference transcripts. Fold change=(2^ – ΔΔC_t). Error bars represent the standard error of the mean (SEM; n=3).