How do we inhibit glucocorticoid?
manfred
Glucocorticoid plays key role in skin abnormalities induced by
psychological stress
BETHESDA, Md (Dec. 1, 2006) -- Inhibiting glucocorticoid, a type of
steroid, can prevent skin abnormalities induced by psychological
stress, according to a new study from the December issue of the
American Journal of Physiology-Regulatory, Integrative and Comparative
Physiology. The new study also shows how psychological stress induces
skin abnormalities that could initiate or worsen skin disorders such as
psoriasis and atopic dermatitis.
The study, "Glucocorticoid blockade reverses psychological
stress-induced abnormalities in epidermal structure and function," was
carried out by Eung-Ho Choi, Marianne Demerjian, Debra Crumrine,
Barbara E. Brown, Theodora Mauro, Peter M. Elias and Kenneth R.
Feingold of the Veterans Affairs Medical Center, San Francisco and the
University of California at San Francisco. Choi is also associated with
Yonsei University Wonju College of Medicine, Wonju, Korea. The American
Physiological Society published the study.
Previous research has shown that psychological stress increases
glucocorticoid production. In addition, it is well recognized that
psychological stress adversely affects many skin disorders, including
psoriasis and atopic dermatitis.
"In this study, we showed that the increase in glucocorticoids induced
by psychological stress induces abnormalities in skin structure and
function, which could exacerbate skin diseases," Feingold explained.
This provides a link for understanding how psychological stress can
adversely affect skin disorders. Blocking the production or action of
glucocorticoids prevented the skin abnormalities induced by
psychological stress.
Skin protects
The skin is the body's largest organ and plays a crucial role in
providing a barrier between the environment and the internal organs. It
protects us from harmful microorganisms, ultraviolet light, toxic
chemicals, and more. However, its most important function is providing
a permeability barrier that prevents us from drying out. We are
approximately 65 percent water and we are able to survive and function
in dry environments because the skin forms a permeability barrier that
prevents the loss of water.
The permeability barrier is located in the outermost layer of the
epidermis, the stratum corneum. The stratum corneum is composed of dead
cells surrounded by lipid membranes which mediate the permeability
barrier. The stratum corneum layer continuously sloughs off, and
therefore must be regenerated. The epidermal cells in the lower
epidermis are continuously proliferating to provide new cells, which
then differentiate, and ultimately die, to form the stratum corneum.
Previous studies have shown that psychological stress disturbs this
elegantly balanced system by decreasing epidermal cell proliferation
and inhibiting differentiation. Additionally, permeability barrier
function is impaired. The researchers hypothesized that the increase in
glucocorticoids induced by psychological stress would cause these
adverse effects on skin function.
Study with hairless mice
They tested their hypothesis by subjecting hairless mice to stress
while either blocking the production of glucocorticoids or preventing
them from acting on the body. The stress was created by placing the
mice in small cages in constant light with a radio playing for 48
hours.
Before placing the mice in the stressful situation, the researchers
treated one group of mice with RU 486, a substance that blocks the
action of glucocorticoids.
A second group of mice received antalarmin, which blocks glucocorticoid
production. A third group was subjected to the stress but received
neither antalarmin nor RU 486. The fourth group, the control group,
remained unstressed in ordinary cages and without the continuous light
and sound to which the other groups were exposed.
Results confirm hypothesis
The stressed mice that received RU 486 and antalarmin showed
significantly better skin function compared to the stressed mice that
did not receive either treatment. The treated mice showed significantly
better:
proliferation
differentiation
permeability barrier function
stratum corneum integrity
The experiment demonstrated the important role that glucocorticoids
play in inducing the skin abnormalities brought on by psychological
stress. While the researchers hope the study will lead to a way to
treat people who suffer these skin conditions, there is still a long
way to go: First, the research was done with mice, not people. Second,
there may be serious side effects of modulating glucocorticoid
activity. Glucocorticoids are essential hormones that play many
important roles. Blocking the action of glucocorticoids could have
negative outcomes that are much worse than exacerbations in the skin
disorders.
The research team is now looking at the effect of psychological stress
on the skin's production of antimicrobial peptides, which play a role
in defense against infection. They hypothesize that psychological
stress might also reduce the ability of the skin to protect from
infections.