Chinese researchers here demonstrate that some forms of fetal stem cell transplant are unambiguously beneficial in mice - the absence of cancerous development is perhaps surprising. This suggests that if an individual's stem cells could be sampled, altered to look more like fetal stem cells, and returned to the body, then they could achieve the same end: a general improvement in tissue repair, bodily systems, and life expectancy. From the paper: "To determine the role of allogeneil graft of mesenchymal stem cells in mammalian longevity, mesenchymal stem cells were isolated from [mouse fetal tissue] and then were purified and amplified by adherent culture. Identified P1 mesenchymal stem cells were injected [into] the 15-month-old [mother mice] three times. The mice were evaluated ... The results showed that after transplantation, the long-term surviving stem cells were found to be located in many organ tissues ... Median life span was increased in these animals after transplantation. Skin, cardiac, lung, kidney and colon pathology development were delayed. [Amongst other markers of aging, the degeneration] of heart function was attenuated [and markers of oxidative stress] were reduced three months after transplantation. These results support the idea that longevity can be enhanced by transplantation of mesenchymal stem cells."