The study identifies a key signaling molecule that tells hair follicles
to start the hair-growing cycle.
"These are very complex molecular signals, and the authors have very nicely shown that there is one molecule, laminins 511, that is a very important signal to tell the hair molecule to move through the process.
Unlike Rogaine or Propecia, products that slow hair
loss, researchers hope the laminin-511 could
potentially regenerate the actual follicles that
grow hair.
"Loss of hair is not going to kill anybody," said
Dr. Peter Marinkovich, the study's senior author and
an associate professor at Stanford University's
School of Medicine. "At the same time, for some
people, hair loss can be a really traumatic thing,
especially for women."
He hopes the treatment eventually could help
patients who suffer from alopecia, a disorder that
can cause hair loss in patches, or speed up hair
growth for chemotherapy patients.
It's part of a basic biological understanding," said Dr. Ronald Crystal, chairman of genetic medicine at New York Presbyterian Weill Cornell Medical Center in New York City.
The researchers, reporting in the Aug. 1 issue of Genes &
Development, feel the findings may one day hold the key
to treating male-pattern baldness, as well as hair loss from
chemotherapy or even to restore hair on burn victims.
But, as so often happens, the study was conducted in mice
and, as Crystal pointed out, "Mice are not just little men
and women. They are different than us and also different in
their hair."
A series of complex molecular signals tell hair follicles to
go through a cycle of follicle growing, hair growing,
follicle receding and hair receding, Crystal explained.
The same group of researchers had previously found that the
protein laminin-511 was important to hair development.
In this study, the authors found out why. It was originally thought that laminin-511 was made from the cells of the outer layer of the skin (epithelium) and acted on the epithelium.
It now turns out, however, that the protein, although
produced by the epithelium, actually penetrates into the
inner layer of the skin (dermis) to kick start the
hair-growing process.
"So laminin-511 is an early epithelial message to the dermis
to say let's start producing hair," said study senior author
Dr. Peter Marinkovich, an associate professor of dermatology
at Stanford University School of Medicine and member of the
Stanford Cancer Center. "Hair is formed as a result of
cooperation and communication between the two layers."
"We knew that the two layers of the skin are important in
hair formation, and we knew that there was some early
epithelial signal hypothesized a long time ago, but no one
knew what it was until now," he added.
In mice, laminin-511 convinced hair to grow at the
equivalent of about the eighth month of pregnancy, but
Marinkovich and his colleagues are hoping it might also work
later in the life cycle.
Male baldness associated with aging would be an obvious
target. "The hair follicles are still there, but they get
stuck in the cycle, so it's not well understood why they're
stuck and . . . how do you get them unstuck," Crystal said.
"The hope, of course, is that you can apply this to humans,
but there are some cautions in all that. Biology is very
complex.
There are a lot of checks and balances. You don't want hair follicles and cells in hair follicles to be growing too much or not enough. The on-and-off signals that are dampening that and controlling that are very, very complex and not well understood. This is far, far from humans."
