Culture Under Low Physiological Oxygen Conditions Improves the Stemness and Quality of Induced Pluripotent Stem Cells

(2)) conditions has been demonstrated to improve the stemness and genomic stability of the cells. We investigated whether low-oxygen culture would be beneficial for the culture of induced pluripotent stem (iPS) cells. (2), 5% O-2, or 20% O-2 and maintained for 2 months in parallel. (2) than at 20% O-2. All of these iPS colonies that expanded under the various oxygen conditions stained positively for Oct3/4, Nanog, SSEA-4, and ALP. However, Western blot analysis showed that the iPS cells cultured at 2.5% and 5% O-2 expressed significantly more Nanog but less 53BP1 than those cultured at 20% O-2. Data from an array CGH showed no significant chromosomal abnormalities, although some genes involved in cellular and metabolic processes were amplified in the low oxygen culture, particularly at 2.5% O-2. Our data suggest that low physiological oxygen culture could improve the stemness and quality of iPS cells, a result that might be associated with the amplification of genes involved in metabolic and cellular processes. Long-term culture will be necessary to confirm whether low physiological oxygen levels also improve genomic stability. J. Cell. Physiol. 228: 2159-2166, 2013. (c) 2013 Wiley Periodicals, Inc.