CLEVELAND, Ohio-- We've all heard of some of the amazing  potential uses of stem cells: growing new tissues and organs for  transplant, treating degenerative conditions such as multiple  sclerosis and heart failure or safely testing new cancer drugs.  
    But much of the promise of future therapies depends on    overcoming some significant technical hurdles and knowledge    gaps.  
    One of those hurdles, understanding how stem cells heal injury,    is now a lot smaller thanks to some cool basic-science research    recently reported from a lab at Rosalind Franklin    University of Medicine and Science in Chicago.  
    Using adult human stem cells typically found in the bone    marrow, called mesenchymal stem cells, or MSCs, the Chicago    team discovered that the stem cells promote healing in diabetic    ulcers by signaling existing cells in the area to turn on the    natural repair process that can be inhibited in people with the    disease.  
    The team, led by Daniel    Peterson, director of the Center for Stem Cell and    Regenerative Medicine at the Chicago Medical School, performed    the experiment in mice. Their study    was published in Stem Cells Translational Medicine.
    Although MSCs have come to be regarded as a cure-all for tissue    injury, researchers have only recently started to gain even the    smallest clue as to how they work.  
    "This is a problem in the whole MSC field," Peterson said. In    most studies, he said, the cells are injected into the    bloodstream, and then disappear, making it difficult to    understand how they work.  
    "What happens is that they kind of get filtered out into the    lungs, and where they're getting into any tissue is a bit of a    mystery," he said.  
    To avoid that problem, Peterson's team applied the MSCs    topically to a diabetic wound on the backs of lab mice. Even    then, though, they couldn't be sure that the MSCs weren't    traveling through the mouse's body and having a systemic    effect. So a second wound on the mouse's back, untreated with    the MSCs, acted as a control. If there were any systemic    healing effect, the untreated wound would get better. If the    effect were local only, it wouldn't.  
    Even when applied topically, the MSCs disappeared quickly,    Peterson said. But the mice healed only in the area where the    MSCs were applied, not in the other wound. And levels of    several types of molecules that are key to signaling and    triggering the healing response -- called Wnt3a, VEGF and    PDGFR-alpha -- rose in the treated area, suggesting that the    MSCs "recruited" the mouse's own stem cells in the vicinity to    do the repair work.  
More here:
Signaling factors may be key to stem cells' healing abilities: Discoveries