1Department of Biochemistry, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
2Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
3Department of Embryology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
4Department of Anatomical Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
In recent years, considerable advances have been made in the field of regenerative medicine. Unlike embryonic stem cells, which pose the problems of ethical concerns and cause severe immunological reactions as well as neoplasma formation after transplantation, umbilical cord blood is a primitive source of mesenchymal stem cells that covers the benefits of both embryonic and adult stem cells. It has been determined that the proliferation capacity of cells is critically linked to the maintenance of the length of telomeres by telomerase activity. Since there is no information accessible regarding the pattern of telomerase activity in UCB-MSCs through several passages, the aim of this study was the evaluation of telomerase activity in UCB-MSCs, as a predisposing factor for cell immortalization. No telomerase activity was detected in UCB-MSCs from several passages applying telomerase rapid amplification protocol (TRAP). Since there is a direct correlation between the activation of telomerase expression and neoplasma formation in adult somatic cells, UCB can be assumed as an excellent source of MSCs for therapeutic application with a high level of safety. According to the histological results, RT-PCR and biochemical assays, MSCs derived from UCB showed high differentiation capacity to bone and cartilage. UCB-MSCs showed very low level of differentiation potential to adipocytes. Our results showed that UCB-MSCs maintain their self-renewal and differentiation potential through several passages. Since a large number of metabolically active cells must be available in cell therapy, high proliferation capacity through several passages is a great advantage for large scale expansion of UCB-MSCs.