Master cells found deep inside hair follicles might offer a new way to treat baldness and burn victims, U.S. researchers reported on Thursday.

So far the cells have only been found in mice but there is no reason to believe they do not also exist in humans, the team at the Howard Hughes Medical Institute and The Rockefeller University in New York said.

The cells, known as stem cells, replace not only hair but also stretches of skin and sebaceous glands, key to healthy skin and hair, the researchers report in this week’s issue of the journal Cell.

In this case the stem cells the researchers found are adult stem cells - immature master cells that retain the ability to change their “type” to some degree.

They are different from stem cells taken from embryos, a more controversial source.

“We’ve identified cells within skin that bear all the characteristics of true stem cells - the ability for self-renewal and the multipotency required to differentiate into all lineages of epidermis and hair,” said Elaine Fuchs, a cell biologist at Rockefeller who led the study.

“This is the first work that indicates a single skin stem cell can generate both epidermis and hair, even after propagation in the lab,” she added.

Fuchs and colleagues now want to look for similar hair follicle stem cells in people.

“With debate about the cells’ multipotency within skin tissue settled, we can now ask whether the stem cells can also make other cell types in addition to hair and skin,” Rockefeller’s William Lowry said in a statement.

“These results open the door to that possibility.”

The stem cells multiplied well in laboratory dishes and when the researchers grafted the cells onto the backs of bald mice, they grew tufts of hair and skin.

Previous work had used genetic manipulation to find the stem cells in the mice but Fuchs and colleagues found a better way to identify the scarce stem cells.

“We found that the surface of the skin stem cells was different than the other cells of the skin, enabling us to use two different antibodies to sort them out from the other skin cells,” said Lowry. “No one had been able to isolate stem cells from the hair follicle in this way before.”

SOURCE: Cell, September 3, 2004.