Via EurekAlert, news of another multipotent stem cell population, grist for the mill of research into regenerative cell therapies: "Samples of periosteal cells were obtained from the tibia of 12 human donors, ranging in age from 24 to 83 years. Following enzymatic release and culture expansion, cell populations were tested for telltale markers of [Mesenchymal stem cells (MSCs)], as well as for their growth and differentiation potential. ... Regardless of donor age, periosteal cells expanded extensively, steadily maintaining growth curves over at least 30 population doublings. They also displayed the hallmarks of MSCs, including long telomeres, the sections of DNA at the end of a chromosome. What's more, the results of the animal experiments proved that expanded periosteal MSCs can contribute to muscle regeneration and form cartilage when implanted into a joint surface defect."