Beyond Hit-and-Run: Stem Cells Leave a Lasting Memory

While mesenchymal stem cells (MSCs) are rapidly cleared from the body following systemic transplantation, their therapeutic benefits typically persist. In this issue, Liu et al. (2015) reveal that the ability of transplanted MSCs to alleviate osteoporosis in systemic lupus erythematosus is maintained through epigenetic changes conferred by secretory action of the MSCs.