Activated HIF-1 measured by TransAM HIF-1 ELISA in hypoxic and normoxic hMSCs. Columns represent mean amounts of activated HIF-1 normalized to amounts per million harvested cells. The assay was performed in three dishes per experimental group; each experiment was repeated four times. Data are presented with the subtracted background (medium alone). Columns represent the average of four experiments combined (n = 12). The bars represent 1 SEM. ×- P < < 0.01. ELISA, enzyme-linked immunosorbent assay; HIF-1, hypoxia inducible factor-1; hMSCs, human mesenchymal stem cells; SEM, standard error of the mean.