Stress really may turn your hair grey
Sign
of the times: Grey hair during ageing is the result of exhaustion and loss of
melanocyte stem cells, so a similar mechanism could be at play with
stress-related greying(Source: sturti/iStockphoto)
There
could be some truth in the anecdotal belief that stress can turn your hair
grey.
The
appearance of grey hairs after periods of stress or skin damage could be the
result of depletion of stem cells from the base of the hair follicle, according
to a new study in mice.
The
study, reported in Nature Medicine , may also point to new methods of treatment for skin
pigmentation disorders such as vitiligo or piebaldism.
Hair and skin are both pigmented by melanin,
produced by cells called melanocytes,which in turn are produced by melanocyte
stem cells that live in a region at the very base of the hair follicle called
the bulge.
Dr Mayumo Ito and colleagues from New York University found that when the skin is damaged or irradiated, these
melanocyte stem cells help to repair skin damage by leaving the bulge and
travelling to the skin to replenish the store of melanocytes in the outer layer
of the skin.
However in the process, they leave the bulge
without its own supply of melanocyte stem cells.
The discovery that the stem cells migrate
without replicating is a surprise, says Associate Professor Rick Sturm,
principle research fellow at the Institute of Molecular Biosciences at the
University of Queensland.
"Normally stem cells only stay where
they're supposed to be, in the bulge region, the cells divide and the daughter
cells go into the hair follicle to create the hair pigment," says Sturm,
who was not involved in the study.
However in the case of a skin injury or UV
exposure, as occurred in this mouse experiment, the stem cells appear to
migrate out without replicating.
"When that happens, if you lose the stem
cells from the bulge region, you lose the capacity to make melanin... so they
get this small number of hair follicles around the injury which become
white," explains Sturm.
Stress and grey hair
The researchers discovered a key receptor
involved with this stem cell migration, called Mc1r, which is triggered by
stress hormones such as adrenocorticotropic hormone (ACTH) and
melanin-stimulating hormone.
They say this may explain why stress is
linked with an increase in grey hairs.
"Stress hormone (ACTH) promotes
melanocyte migration from hair follicle to epidermis in mice and we thought it
would be interesting to speculate that excessive stress might promote this
migration too much at the expense of preserving melanocytes within the hair
follicle," says Ito.
Grey hair during ageing is the result of
exhaustion and loss of melanocyte stem cells, says Sturm, so a similar
mechanism could be at play with stress-related greying.
"Certainly stress can affect the stem
cells and one way to lose or go completely grey is to lose your stem cells
quicker," he says.
The discovery could also lead to treatments
for conditions such as vitiligo -- depigmentation of the skin -- and to prevent
hyperpigmentation, which is too much pigment in the skin.
"If
we can know more about how melanocytes migrate from hair follicle area to the
epidermis, we may get the ability to promote this process for the treatment of
hypopigmentation disorders," says Ito.
"Our
results suggest that melanocyte migration from the hair follicle to the
epidermis may partly contribute to skin pigmentation, thus inhibition of this
migration process may be a novel approach to prevent UV induced
hyperpigmentation, or post-inflammatory hyperpigmentation commonly seen after
surgery."
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