Proliferative Capacity and Pluripotent Characteristics of Porcine Adult Stem Cells Derived from Adipose Tissue and Bone Marrow

Direct reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) provides an invaluable resource for regenerative medicine. Because of some ethical and logistical barriers, human iPSCs cannot be used to generate a chimera, which is one of markers representing pluripotency. As the most attractive model for preclinical studies, pigs offer another path to improve clinical medicine. In this study, porcine adult stem cells (pASCs), including adipose mesenchymal stem cells (AMSCs) and bone marrow mesenchymal stem cells (BMSCs), were collected and cultured under the same conditions in vitro. Real-time PCR, immunocytochemical staining, apoptosis analysis, and induced differentiation and reprogramming techniques were used to investigate the proliferative capacity and pluripotent characteristics of pASCs. Our results showed that both AMSCs and BMSCs displayed a similar immunophenotype, and their proliferative capacity appeared as a downward trend as the cell passage number increased. The cell proliferative capacity of AMSCs was significantly lower than that of BMSCs (p<0.05). Moreover, each type of pASCs went through 20 passages without undergoing alterations in the expression of reprogramming transcriptional factors (Oct4, Sox2, c-Myc, and Nanog). All pASCs had adipogenic and osteogenic differentiation potential. In addition, they also could be reprogrammed to pig induced pluripotent stem cells (piPSCs) with similar time and efficiency. In conclusion, porcine BMSCs had a higher proliferative capacity than AMSCs, and the pluripotency of pASCs was stable in long-term culture.