High OCT4 and Low Expressions Determine In Vitro Lifespan of Mesenchymal Stem Cells

Figure 4

High OCT4 gene expression as a robust early marker of BM-MSC lifespan. The gene expression levels of (a) OCT4, (b) NANOG, and (c) SOX2 in early passage cells from each donor were analyzed by real time PCR. Relative gene expression levels were quantified using the ΔΔCt method and the results were normalized to the expression of GAPDH. Bar graphs on the left represent the mean fold change of the normalized gene expression relative to a calibrator sample (reference RNA). These values were then plotted against the final PD number and statistically analyzed by Spearman correlation, as shown in the graphs on the right. The expression levels of OCT4 in early passage cells were positively correlated with lifespan. Results are representative of two independent experiments, each performed in duplicate, with similar results.

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