http://dailynews.yahoo.com/h/nm/20011022/hl/bowel_1.html
Monday October 22 5:24 PM ET
NEW YORK (Reuters Health) - Research
into the immune system's inflammatory proteins has uncovered two new potential
ways to fight inflammatory bowel disease (IBD).
In one study, investigators found
that blocking an enzyme that regulates certain inflammatory proteins prevented
intestinal inflammation in mice. A second research team garnered similar
results when they blocked another protein that helps mediate inflammation.
The findings suggest two new targets
for drugs to fight IBD, according to the researchers. And in one case,
such drugs are already under study.
IBD is a general term for diseases
that cause chronic inflammation in the digestive system, with ulcerative
colitis and Crohn's disease being the two major types. Ulcerative colitis
is marked by inflammation in the lining of the colon and rectum, and Crohn's
typically occurs in the small intestine, although it can affect any part
of the digestive system. Symptoms of both include diarrhea, abdominal pain,
weight loss and bleeding. No medication can cure the disorders.
While the exact cause of Crohn's
and colitis is unclear, scientists believe that an abnormal immune response
causes the chronic inflammation that marks the disorders. So some of the
drugs used to control them target the immune system. For example, a relatively
new drug for moderate to severe Crohn's disease called infliximab suppresses
the inflammatory protein tumor necrosis factor (TNF). But more treatments
are needed, as different patients have different responses to existing
drugs.
In one of the new studies, researchers
at the University of Colorado Health Sciences Center in Denver found that
blocking an enzyme called interleukin-1-beta-converting enzyme (ICE) prevented
mice from developing chronic colitis. In contrast, mice with normally functioning
ICE showed colon abnormalities, lost weight and had bleeding and diarrhea.
The findings were published Monday
in the online early edition of the Proceedings of the National Academy
of Sciences (news - web sites).
ICE inhibitors are now in clinical
trials for rheumatoid arthritis, another inflammatory disease marked by
an abnormal immune response. ICE inhibition may also offer a new treatment
for IBD, Britta Siegmund, the study's lead author, told Reuters Health.
She noted that ICE inhibitors could
have an advantage over anti-TNF drugs in that they can be given orally.
In the other study, researchers led
by Ype P. de Jong of Beth Israel Deaconess Medical Center in Boston, Massachusetts,
looked at an inflammatory protein called macrophage-migration inhibitory
factor (MIF).
They found, similarly, that mice
lacking MIF failed to develop chronic colitis. Moreover, they discovered
that treating affected mice with anti-MIF therapy suppressed the disease.
And, hinting at what the finding
could mean for humans, the researchers also found that MIF was elevated
in the blood of a group of Crohn's disease patients.
Taken together, the study authors
conclude, these findings suggest that ``intervention in MIF signalling
could form a future target for the treatment of Crohn's disease.''
Their findings were published Monday
in the online advance edition of Nature Immunology.
SOURCE: Proceedings of the National
Academy of Sciences Early Edition 2001;10.1073; Nature Immunology online
22 October 2001;10.1038.
Copyright © 2001 Reuters Limited
By Amy Norton