Safety of umbilical cord blood-derived mesenchymal stem cells (MSCs) following 5-azaserine induction and inhibition of human cardiac myocyte apoptosis by MSCs.

Objective: To further study the safety and effect of the umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) on apoptosis of human cardiac myocyte (HCM).

Methods: The UCB was collected at the time of delivery with informed consent obtained from 10 donors. The UCB-derived MSCs was treated with 5-azaserine (5-AZA), and further introduced differentiation into cardiomyocytes. The telomerase activity, G-banding patterns of chromosomal karyotypes, tumor formation in nude mice, reverse transcription polymerase chain reaction (RT-PCR), and the inhibited apoptosis of UCB-derived MSCs were further investigated. This study was carried out in the laboratory of Beijing Shijitan Hospital, Beijing, China and Inheritance Research Section of Chinese Medical Institute, Beijing, China from July 2005 to December 2007.

Results: The MSCs-derived from UCB were differentiated into cardiomyocytes in vitro, possessed telomerase activity after 5-AZA induction, and no abnormal chromosomal karyotypes were observed. Expression of p53, cyclinA, cdk2, -actin, C-fos, h-TERT and c-myc were similar in MSCs before and after 5-AZA treatment. There was no tumor formation injected into nude mice. The UCB-derived MSCs significantly inhibited apoptosis of human cardiomyocytes.

Conclusion: Umbilical cord blood-derived MSCs are safe and effective source of cell-transplantation treatment, and can inhibit the apoptosis of human cardiomyocytes in co-cultured.