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VA RESEARCHERS DISCOVER CAUSE OF ROSACEA
SKIN CONDITION -- Spicy foods, heat, alcohol
and even
embarrassment can trigger rosacea. Now, doctors
know what causes the condition.
For more information on VA research, use the VA
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Story here...
http://www.sciencedaily.com/
releases/2007/08/070805161110.htm
Story below:
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Cause Of Skin Condition Rosacea Discovered
Science Daily — Doctors can describe the symptoms of rosacea, a common
inflammatory skin disease that causes facial redness and affects nearly
14 million Americans. They can tell patients what triggers can worsen
their condition: spicy foods, heat, alcohol, even embarrassment. But
until now, they could not explain what caused rosacea.
A team of researchers, led by Richard L. Gallo, M.D., Ph.D., professor
of medicine and chief of the Division of Dermatology at the University
of California, San Diego (UCSD) School of Medicine and the Dermatology
section of the Veterans Affairs San Diego Healthcare System, has
determined that it is not one, but a combination of two abnormal
factors, that result in rosacea.
"It's like having lots of gasoline...and a match," said Gallo, principal
investigator of the study which will be published in the August 5 online
edition of Nature Medicine. In essence, the researchers found that
over-production of two interactive inflammatory proteins results in
excessive levels of a third protein that causes rosacea symptoms, "a
trifecta of unfortunate factors in people with rosacea," according to
Gallo.
Rosacea, which has been called adult acne, usually affects people with
fair skin, between the ages of 30 and 60. Unlike acne, rosacea isn't
associated with a skin infection by one type of bacteria, although
antibiotics are sometimes prescribed to treat its symptoms. A chronic
condition, it gets worse over time and is generally cyclic, flaring up
for a period of weeks to months, and then subsiding for a time. Current
treatments are often not effective.
Gallo and his colleagues first observed in the laboratory that
anti-microbial peptides -- small proteins of the body's host defense
system -- caused the exact same symptoms in the skin that rosacea does,
such as redness, an increase in visible blood vessels, bumps or pimples.
The peptides also reacted to the same triggers.
"When we then looked at patients with the disease, every one of them had
far more peptides than normal." said Gallo.
To learn why these patients have abnormal peptides, the researchers
examined the source of these molecules. The precursor form of these
peptides, called cathelicidin, is normally known for its function to
protect the skin against infection. In other skin diseases, a deficiency
of cathelicidin correlates with increased infection. In rosacea
patients, researchers found the opposite was true; too much cathelicidin
was present in their skin. They also observed that it was a different
form than found in people without the skin disorder.
Patients with rosacea also had greatly elevated levels of enzymes called
stratum corneum tryptic enzymes (SCTE). These enzymes turned the
precursor into the disease-causing peptide. By injecting mice with the
cathelicidin peptides found in rosacea, or adding SCTE, they increased
inflammation in the mouse skin, thus proving that these abnormalities
can cause the disease.
"Too much SCTE and too much cathelicidin leads to the abnormal peptides
that cause the symptoms of this disease," said Gallo. "Antibiotics tend
to alleviate the symptoms of rosacea in patients because some of them
work to inhibit these enzymes. Our findings may modify the therapeutic
approach to treating rosacea, since bacteria aren't the right target."
Additional contributors to the research include Kenshi Yamasaki, Anna Di
Nardo, Antonella Bardan, Alvin Coda, Robert A. Dorschner and Vera B.
Morhenn, Division of Dermatology, UC-San Diego and VA San Diego Health
Care System; Masamoto Murakami and Takaaki Ohtake, Asahikawa Medical
College, Asahikawa, Japan; Chrystelle Bonnart and Pascal Descargues,
Inserm and Université Paul-Sabatier, Toulouse, France; and Alan
Hovnanian, CHU Purpan and Université Paul-Sabatier, Toulouse, France.
Note: This story has been adapted from a news release issued by
University of California - San Diego.
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Larry Scott --
