Human first trimester fetal mesenchymal stem cells (MSC) express pluripotency markers, grow faster, and have longer telomeres compared to adult MSC

¹ Experimental Fetal Medicine Group, Institute of Reproductive and Developmental Biology, Imperial College London, Hammersmith Campus, London, United Kingdom
² Experimental Fetal Medicine Group, Institute of Reproductive and Developmental Biology, Imperial College London, Hammersmith Campus, London, United Kingdom; Centre for Fetal Care, Queen Charlotte's & Chelsea Hospital, London, United Kingdom

^* To whom correspondence should be addressed. E-mail: pascale.guillot{at}imperial.ac.uk.

	Abstract

The biological properties of stem cells are key to the success of cell therapy, for which mesenchymal stem cells (MSC) are promising candidates. Although most therapeutic applications to date have used adult bone marrow MSC, increasing evidence suggests that MSC from neonatal and mid-gestational fetal tissues are more plastic and grow faster. Fetal stem cells have been isolated earlier in development, from first trimester blood and haemopoietic organs, raising the question of whether they are biologically closer to embryonic stem cells and thus have advantages over adult bone marrow MSC. In this study, we show that human first trimester fetal blood, liver and bone marrow but not adult MSC express the pluripotency stem cell markers Oct-4, Nanog, Rex-1, SSEA-3, SSEA-4, Tra-1-60 and Tra-1-81. In addition, fetal MSC irrespective of source had longer telomeres (p<0.001), greater telomerase activity (p<0.01), and expressed more hTERT (p<0.01). Fetal MSC were also more readily expandable and senesced later in culture than their adult counterparts (p<0.01). Compared to adult MSC, first trimester fetal tissues constitute a source of MSC with characteristics that appear advantageous for cell therapy.