Signaling factors may be key to stem cells’ healing abilities: Discoveries

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.

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Signaling factors may be key to stem cells' healing abilities: Discoveries