Acne Rosacea: [rosacea] Stress and skin

Tuesday, December 05, 2006

[rosacea] Stress and skin

Glucocorticoid Plays Key Role In Skin Abnormalities Induced By
Psychological Stress
Main Category: Dermatology News
Article Date: 05 Dec 2006 - 5:00am (PST)

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.