Stem Cells Recruit Others to Do Work

Much like Tom Sawyer painting the fence, researchers at the Chicago Medical School at Rosalind Franklin University of Medicine and Science have discovered that mesenchymal stem cells (MSC) send out “homing signals” that recruit other stem cells and mobilize them to do the work of healing wounds. They found that MSC s are better at initiating the healing process than they are at directly repairing tissue damage themselves. The researchers explain their discovery in an article published in STEM CELLS Translational Medicine.

Researchers Daniel Peterson and Laura Shin took MSC cells extracted from human bone marrow and grafted them into wounds of healthy mice and mice with diabetes. Mice in both groups had two separate wounds to better allow the researchers to study the precise role the cells played in healing. Some mice in each group received MSC cells in one wound while others did not receive the cells. After studying the differences in healing, signaling and cell populations in the mice, Peterson and Shin learned that both normal and impaired mice given MSC cells healed more quickly, even in wound, than did those that did not receive direct MSC cell grafts.

“The mice that received MSC cells demonstrated a systemic response, ” Peterson said. “This suggests that the key to repairing injured tissue does not hinge on where you place the MSC cells in the body, but on learning exactly how the MSC cells recruit their counterparts already in the body.” Peterson believes that discovering more about the signals MSC cells use to trigger the body’s own stem cells to heal could lead to new cell-free therapies. Scientists could develop treatments using small molecules or drugs as an alternative to costly cell-mediated therapies.

“These findings broaden our view of therapeutic targets to include the host response, ” he said. “The improvement in impaired and normal wound healing has significant clinical relevance for all wounds, chronic and acute.”

“This study indicates that signals within the wound bed may be activated after engraftment, suggesting that controlling mobilization is a key to success in future therapies, ” said Anthony Atala, MD, Editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.