APLN enhances the growth of endothelial and hematopoietic cells from CD34^brKDR^br progenitors. (A) Flow cytometric analysis of KDR and CD34 expression in day 6 EBs differentiated under endothelium-inducing growth conditions (BV^hiS). The CD34^brKDR^br sorted cell population is indicated by the boxed area. (B-H) Microarray expression data for the indicated genes in undifferentiated hESC cells (hESC), day 6 CD34^brKDR^br sorted progenitor cells (d6), CD34^brKDR^br cells cultured in vitro for an additional 6 days (d6 + 6), and HUVEC cells. (I) Histogram showing the fold expansion after culturing 1.5 × 10⁴ sorted day 6 CD34^brKDR^br cells for 8 days in medium supplemented with the indicated concentrations (ng/mL) of VEGF and APLN. Error bars represent SEM for n = 5 independent experiments. *P < .0005 for VEGF/APLN vs VEGF. (J) Histogram showing the mean frequency of hematopoietic colony-forming cells in methylcellulose cultures seeded with day 6 sorted CD34^brKDR^br progenitor cells, cultured with VEGF, SCF, and EPO in the presence or absence of 50 ng/mL APLN. Error bars represent SEM for n = 6 independent experiments. *P < .03 for APLN addition.