From the SENS Foundation: "Progress toward the goal of tissue rejuvenation via stem cells and tissue engineering ("RepleniSENS") is badly hampered by the surprising fragility of human embryonic stem cells (hESC) relative to mouse ESC (mESC). Unlike their murine counterparts, hESC undergo extensive cell death following enzymatic single-cell dissociation; as a result, researchers are forced to rely on laborious mechanical microdissection, or on narrowly-control enzymatic dissociation that ensures that hESC remain above a minimum cluster size. These requirements make their expansion extremely tedious and inefficient. The reasons for the intolerance of hESC to full dissociation - and the development of means to ameliorate it - are therefore of considerable biomedical as well as scientific interest. This month, researchers [report] that they have at once apparently provided the detailed molecular basis for this frustrating anomaly, and its abrogation using either modified culture protocols or either of two small molecules. ... Injected into an area that already enjoys a high level of government and industry investment, these tools bring us closer to realizing the promise of cell therapies and tissue engineering for the treatment of a range of age-related and traumatic diseases and disorders, as well as for the rejuvenation of aging tissues."