Study of telomerase activity, proliferation and differentiation characteristics in umbilical cord blood mesenchymal stem cells

In recent years, considerable advances have been made in the field of regenerative medicine. Unlikeembryonic 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 ofmesenchymal stem cells that covers the benefits of both embryonic and adult stem cells. It has beendetermined that the proliferation capacity of cells is critically linked to the maintenance of the length oftelomeres 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 detectedin UCB-MSCs from several passages applying telomerase rapid amplification protocol (TRAP). Since thereis a direct correlation between the activation of telomerase expression and neoplasma formation in adultsomatic cells, UCB can be assumed as an excellent source of MSCs for therapeutic application with a highlevel of safety. According to the histological results, RT-PCR and biochemical assays, MSCs derived fromUCB showed high differentiation capacity to bone and cartilage. UCB-MSCs showed very low level ofdifferentiation potential to adipocytes. Our results showed that UCB-MSCs maintain their self-renewal anddifferentiation 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.