Whether the treatments will have similar results on humans is not yet known. Smart and Oh are now working with a dermapathologist at Wake Forest University's Bowman-Gray School of Medicine to determine if the estrogen receptor that regulates hair growth in mice also is present in man. If found to be safe and effective on humans, the treatments could be used for hair loss caused by chemotherapy, male pattern baldness or gradual thinning, as well as for treating hirsutism, the excessive growth of unwanted hair. Smart estimates it could take five years or more before the testing is completed and the treatments are available commercially. A more immediate benefit, he says, is the new light the research sheds on estrogens' role in regulating the hair-growth cycle.
Hair follicles are complex, self-renewing structures composed of different types of cells.
Dermal papilla cells at the base of the hair follicle have long been known to regulate the transition between the growth and resting phases of the hair- follicle cycle, but no one was exactly sure how. We didn't know what signals were given out by these cells to trigger other cell types into proliferating and forming an active follicle. Smart's research team, which includes both graduate and undergraduate students, answered part of this question by demonstrating that it is an estrogen receptor pathway, located in the nucleus of the dermal papilla cell, that regulates the growth cycle. His team's findings about how estrogen regulates the follicular stem cells responsible for hair growth may also open new avenues of investigation in cancer research, Smart believes. Follicular stem cells may represent the precursor cells for certain skin cancers.