The skin is known for its ability to regenerate because the cells in the skin are constantly turning over. This “healing property” has attracted much attention from scientists wanting to know what makes the skin repair itself. Researchers at the University of Toronto and the Hospital for Sick Children (SickKids) are now a step closer to understanding its regenerative power. The scientists are the first to identify a stem cell for the dermis or the second layer of the skin. The study is published in the Dec. 4 issue of Cell Stem Cell.
Researchers found that a group of cells called skin-derived precursors (SKPs) act as the dermal stem cells. Stem cells are cells that are able to retain their capability of making many different types of cells. The study shows that these SKPs can maintain the dermis and participate in wound healing.
“Understanding the regeneration of the dermis is very important in understanding how wounds heal,” said Professor Freda Miller of molecular genetics, the study’s principal investigator and a senior scientist at SickKids. “If we can understand wound healing, then we can address the many conditions and diseases that involve wounds that don’t repair themselves.”
Miller and her team were one of the first to show that the skin is an accessible source of stem cells that can generate non-skin cell types and have been using these stem cells for their work on spinal cord injury. “It is perhaps not surprising that SKPs turn out to be an endogenous dermal stem cell since the dermis includes many different cell types such as blood cells, fat cells and nerves.”
The study showed that SKPs not only maintained skin and healed wounds; they also made hair grow. To do this, the SKPs acted as “bandleaders telling the rest of the musicians on the upper level of the skin [epidermis cells] to make hair follicles,” she explained.
And while there are many studies focused on cell therapy or bringing new cells into a tissue to treat disease, Miller hopes to further advance the field of personalized medicine by identifying and understanding stem cells.
“I think a lot of people in the field are hoping that one day we won’t even have to think about cell therapy and we will be able to harness the stem cells our own tissues to repair the body,” Miller said. “Imagine if it would be possible to give someone a drug to recruit their own stem cells and thereby repair their tissues.”
This research was supported by grants from Canadian Institutes of Health Research, the Canadian Stem Cell Network, Howard Hughes Medical Institute and SickKids Foundation.