Virus Might Contribute to Obesity
- From: "georgia" <jwissmille@xxxxxxx>
- Date: 13 Apr 2005 12:58:37 -0700
Friday July 28, 2000 10:17 AM ET
Virus Might Contribute to Obesity
By Amy Norton
NEW YORK (Reuters Health) - Poor eating habits, sedentary lifestyles,
and genes have all been implicated as contributors to
obesity. Now researchers have evidence that suggests another
possibility--that a virus may trigger fat accumulation in some
people.
In experiments with chickens and mice, researchers found that a virus
known as human adenovirus-36 (Ad-36) caused the
animals to gain excessive amounts of fat. In contrast, chickens
infected with a bird adenovirus called CELO did not pack on
excess fat.
While these results do not point to Ad-36 as a cause of human obesity,
they do suggest that one or more viruses may be behind
some people's weight woes, Dr. Nikhil V. Dhurandhar told Reuters
Health.
In general, adenoviruses cause colds, diarrhea and eye infections, but
little is known about how Ad-36 is spread or the types of
infections it might cause. The researchers settled on Ad-36 because it
does not cross-react with other adenoviruses, meaning it
likely has ``unique qualities,'' Dhurandhar said. And, he said, no one
has else has studied it.
Dhurandhar, of Wayne State University in Detroit, Michigan and his
colleagues report their findings in the August issue of the
International Journal of Obesity.
The idea that a virus may trigger obesity is not new to the animal
world. Four viruses have been shown to cause fat accumulation
in animals, Dhurandhar noted. ``This,'' he said, ''is the first time a
human virus has been associated with obesity.''
Dhurandhar came across his first circumstantial evidence of a viral
cause for human obesity in his native India. He and his
colleagues discovered that a chicken adenovirus isolated in Bombay
caused chickens to accumulate fat. Surprisingly, the virus also
lowered the animals' cholesterol levels. Dhurandhar's team next looked
for evidence of infection with the chicken virus in a group
of 52 obese people. The researchers found that 10 showed signs of
infection. More importantly, these people were the most
obese, yet had lower cholesterol than those who were not infected with
the chicken adenovirus.
Because the US would not allow Dhurandhar to import the Bombay chicken
virus for study, he and his colleagues decided to
investigate whether a human virus might be involved in fat
accumulation.
In four separate experiments, Dhurandhar's team found that the animals
infected with Ad-36 packed on fat, but showed
''paradoxically low'' cholesterol levels. Why this happened is
unclear. Damage to the areas of the brain that control calorie use is
a
possibility, but Dhurandhar and his colleagues found no evidence of
that in these experiments.
Much more study is needed to determine whether obesity is indeed an
infectious disease. It may be that in some cases, Ad-36 or
another virus interacts with obesity-linked genes or poor diet. Or,
Dhurandhar said, it's possible that a virus alone leads to obesity
in some people. ``We see it in animals,'' he noted.
What's important, according to Dhurandhar, is that scientists
recognize the possibility that infectious organisms could play a
role--just as they are thought to do in ulcers and heart disease.
``Even if just 10% of obesity cases have a viral contribution,'' he
said, ``we should go after it.''
SOURCE: International Journal of Obesity 2000;24:989-996.
_______________________________
New human virus tied to obesity
Ben Harder
>>From San Diego, at Nutrition Week
Researchers have identified the second member of a class of human
viruses
that
may increase people's susceptibility to obesity. Previous studies have
shown
that people and lab animals infected with a virus known as human
adenovirus-36,
or Ad-36, are more likely to be obese than are uninfected individuals.
A new
study finds that a closely related adenovirus from people causes excess
fat
to
accumulate in chickens infected with the virus.
Richard L. Atkinson of the University of Wisconsin-Madison and his
colleagues
sprayed human adenoviruses Ad-2, Ad-31, and Ad-37 into the nasal
passages of
young chicks to test for the effects they had seen with Ad-36.
Four weeks later, chicks infected with Ad-37 had an average of 6 grams
of fat
stored around internal organs, compared with about 2 g for chicks
infected
with
Ad-2 or Ad-31 or chicks free of adenoviruses. All chicks received
similar
diets, and overall body weights weren't significantly different among
the
groups. Atkinson says that physiological measurements hint at multiple
mechanisms, still unknown, underlying the viruses' role in fat
accumulation.
References:
Atkinson, R.L., et al. 2002. Evaluation of human viruses as an etiology
of
obesity in chickens (Abstract 133). Nutrition Week. Feb. 23-27. San
Diego.
Further Readings:
For information about Nutrition Week, see
http://www.nutritionweek.com/.
Sources:
Richard L. Atkinson
Department of Clinical Nutrition
University of Wisconsin-Madison
1415 Linden Drive
Madison, WI 53706
>>From Science News, Vol. 161, No. 11, March 16, 2002, p. 173.
Copyright ©2002 Science Service. All rights reserved.
1719 N St., NW, Washington, DC 20036 | 202-785
______________________________
.
- Prev by Date: BACTERIAL TOXINS AND CANCER
- Next by Date: In Vitro Susceptibility Testing of Borrelia burgdorferi Sensu Lato Isolates Cultured from Patients with Erythema Migrans before and after Antimicrobial Chemotherapy
- Previous by thread: BACTERIAL TOXINS AND CANCER
- Next by thread: In Vitro Susceptibility Testing of Borrelia burgdorferi Sensu Lato Isolates Cultured from Patients with Erythema Migrans before and after Antimicrobial Chemotherapy
- Index(es):
Relevant Pages
|
