CONTACT: DAVE PEDERSEN
2130 Medical Laboratories
Iowa City IA 52242
(319) 335-8032; fax (319) 335-8034
Release: August 9, 1999
UI researchers use intestinal worms to treat inflammatory
IOWA CITY, Iowa -- Intestinal worms may hold the key
to treating inflammatory bowel disease, according to University of Iowa Health
Inflammatory bowel disease refers to two conditions,
ulcerative colitis and Crohn's disease, that are chronic diseases of intestines
that cause abdominal pain, diarrhea and gastrointestinal bleeding. The diseases
usually begin in people during their late teens and twenties and can last
UI researchers Joel Weinstock, M.D., professor of
internal medicine; David Elliott, M.D., assistant professor of internal medicine;
and Robert Summers, M.D., professor of internal medicine, noted that Crohn's
disease has increased substantially in the United States and Europe over the
past 60 years. Moreover, Crohn's disease and ulcerative colitis are rare in
"These observations suggested that there is some critical
environmental factor responsible for the development of inflammatory bowel
disease," said Weinstock, director of the Digestive Disease Center at the
UI Hospitals and Clinics. "We believed that the absence of the helminthic
worms in the intestines was an important factor leading to the development
of Crohn's disease and ulcerative colitis."
While the cause of inflammatory bowel disease remains
undetermined, it is presumed to result from poor regulation of the intestinal
immune system. Inflammatory cells in the gut protect us from its normal contents,
and this highly effective chronic inflammation is tightly controlled. Thus,
inflammatory bowel disease may result from inappropriately vigorous immune
responses to normal intestinal bacteria, Weinstock said.
Helminthic is the scientific term that is used to
describe various types of worms, some of which live in our gastrointestinal
tract. More than one-third of the world's population carries one or more of
these organisms. The prevalence of helminths is highest in warm climates where
people live under less sanitary conditions.
The researchers noted that the rise of inflammatory
bowel disease was preceded by a decrease in intestinal worm infections.
"These worms have been with us for more than 3 million
years," Weinstock said. "Our intestinal immune systems have adapted to their
presence. These worms normally dampen our mucosal immune response. Without
them, we are more likely to produce powerful inflammatory substances that
induce poorly controlled inflammation."
Animal studies conducted by Elliot supported this
contention. He found that mice exposed to helminthic worms were protected
from the development of inflammatory bowel disease.
Therefore UI researchers, led by Summers, organized
a clinical study to determine if a helminthic parasite could be given safely
to patients with inflammatory bowel disease. Six patient volunteers were given
a single dose of microscopic parasite eggs. Four of the patients had Crohn's
disease and two had ulcerative colitis. Each patient was seen in the clinic
every two weeks using questionnaires and laboratory tests to closely monitor
whether they had side effects or other health problems.
Interestingly, all of the patients improved substantially.
This included a reduction in diarrhea and abdominal pain and improved energy
level. The improvements lasted about four weeks, suggesting that additional
doses might be needed. Preliminary results suggest that additional doses can
be effective in prolonging the benefit of the treatment.
The UI researchers noted that the results are encouraging,
but additional clinical studies are required to further establish this approach
as being safe and effective. They are now organizing a double-blind, clinical
trial with additional patients to further test the benefit of this unique