The effect of human embryonic stem cells hESCs l

Authors: Vladimir Zachar Sinha M Prasad Simon C Weli Anette Gabrielsen Karsten Petersen Michael B Petersen Trine Fink

Publish Date: 2010/02/23

Volume: 46, Issue: 3-4, Pages: 276-283

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Abstract

The maintenance of pluripotency of human embryonic stem cells hESCs requires a high efficiency of selfrenewal During in vitro propagation however spontaneous differentiation occurs frequently and there is also a risk of chromosomal changes In this study we assessed the properties of hESCs after longterm culture at ambient air and 5 oxygen growth conditions The hESC lines were grown for up to 42 and 18 mo in normoxic and hypoxic conditions respectively and their proliferation expression of Oct4 SSEA1 Nanog and Notch1 karyotype telomerase activity and differentiation potential in vitro were evaluated In contrast to cultures at 20 oxygen where the central zones of the colonies underwent spontaneous differentiation during exposure to 5 oxygen the hESC colonies maintained a homogenous and flat morphology that was consistent with the presence of Oct4positive undifferentiated phenotype Irrespective of oxygen concentration the undifferentiated cells expressed high levels of Nanog and Oct4 transcripts normal karyotype and high telomerase activity When assayed for differentiation potential they yielded derivatives of all three embryonic germ layers Our data thus indicate that hypoxic exposure has the capacity to sustain enhanced longterm selfrenewal of hESCs The hESC lines described in the current paper can be obtained for research purposes from the Laboratory for Stem Cell Research Aalborg UniversityThe authors wish to recognize financial support from The John and Birthe Meyer Carlsberg and Toyota Foundations and the EU LSHCCT2003502932 EUROXY and Danish Medical Research Council 2052010045 grants The expert technical assistance of Ole Jensen and Helle Skjødt Møller is highly appreciated

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