Analysis of the quantitative effects of the small molecules used on erythroid differentiation of H1 embryonic stem cells (ESCs). (A): Additional use of small molecules increased the yield of erythroid cells. Histograms representative of the small molecule effect on the yield of erythroid cells from the H1 hESC line, expressed as percentage of total amplification relative to the control. Left panel, effect of inhibitor VIII and IBMX assessed at day 24 of the differentiation. n = 3; mean ± SD. Unpaired t test; ∗, p < .05. Right panel, effect of SR1 and SR1 + SC1 assessed on day 31 of the differentiation, when used in addition of Inhibitor VIII and IBMX. n ≥ 4; mean ± SD. Unpaired t test; ∗, p < .05, ∗∗, p < .01. (B): Inhibitor VIII and IBMX addition increase the transcription of key genes involved in hematopoiesis. Quantitative polymerase chain reaction analysis of the effect of inhibitor VIII and IBMX at day 10 of the differentiation on genes known to be expressed during hematopoietic and erythroid development. n = 4 performed in duplicate; mean ± SD. Unpaired t test; ∗, p < .05; ∗∗, p < .01; ∗∗∗, p < .001. Abbreviations: IBMX, isobutyl methyl xanthine; ns, not significantly different.