Stem cells -- isolated from embryos or from adult tissue -- are immature progenitor cells with the capability to differentiate into a variety of specialized cells that form tissues and organs. Scientists are working toward using stem cells to grow mature specialized cells that could regenerate damaged or diseased skin, brain, heart or other organs. The new findings constitute another step toward understanding how to mimic the chemical signals that the cells require to differentiate into mature tissues, according to Howard Hughes Medical Institute investigator Elaine Fuchs. Fuchs and colleagues at The Rockefeller University published their findings in the September 3, 2004, issue of the journal Cell.
According to Fuchs, previous studies in her laboratory and others suggested that a structure called the bulge, which is located within each hair follicle, might contain stem cells. Those studies hinted that the stem cells might provide the source of both new skin and hair follicles.
"However, two major questions remained," said Fuchs. "One was whether there was a single type of multipotent stem cell within the bulge, or a bag of different kinds of stem cells -- some of which could repopulate the epidermis and others that could produce hair follicles.
"The second major question was whether these cells were capable of undergoing self-renewal. And of particular interest to clinicians was whether they could undergo division in a lab dish and still have the capability to perform either epidermal repair or hair-follicle generation."