|
Getting
the Dirt on Parkinson's
Excerpt
by Jennifer Thomas, HealthScoutNews
(HealthScoutNews)
-- A bacteria commonly found in soil may trigger Parkinson's disease,
says a new study.
The bacteria
Nocardia asteroides causes permanent changes in brain chemistry
and produces tremors and muscle rigidity in some laboratory animals,
the researchers report.
"This
could potentially be very significant," says lead study researcher
Blaine Beaman, professor of medical microbiology at University
of California at Davis. "If Nocardia is involved in the development
of Parkinson's disease -- and I think it is -- understanding the
mechanism might permit the development of prevention and therapy."
The study
will be presented tomorrow at the biannual meeting of the Society
for General Microbiology at the University of East Anglia in England.
Nocardia
asteroides is known to cause infections of the lungs and skin
in humans and animals, entering the body mainly through inhalation
of dust, Beaman says.
Though the
prevalence of illnesses caused by Nocardia has not been determined,
one large study found half the population has antibodies to it,
indicating exposure to the bacteria is common, Beaman says.
Because illnesses
caused by Nocardia can be mistaken for other lung infections,
Nocardia is not often fingered as the culprit, Beaman says.
Beaman and
his colleagues injected mice and monkeys with the Nocardia bacterium.
About 10 percent to 20 percent of the animals developed Parkinson's-like
symptoms, the study found.
Autopsies
on the animals showed the bacteria had traveled to the brain and
caused irreversible damage.
Using tissue
cultures, researchers determined the bacteria killed nerve cells
in the substantia nigra, the portion of the brain responsible
for producing dopamine, a brain chemical that controls motor skills
and movement. A lack of dopmine causes the tremors and stiffness
typical of Parkinson's.
Parkinson's,
a degenerative diseases, afflicts 1 million Americans.
The exact
cause of Parkinson's disease is not known, but recent research
has implicated pesticides, herbicides and genetic factors.
Dr. Robert
G. Feldman, professor of neurology, pharmacology and environmental
health at Boston University, is very skeptical that a bacterium
is the cause of Parkinson's. If bacteria commonly found in the
soil were to blame, many more people would have Parkinson's, he
says.
Also, he says
many environmental substances, including lead, manganese, iron
and some pesticides, can cause changes in brain chemistry. The
key to unlocking the mystery of Parkinson's is to determine the
genetic factors that interfere with the mechanisms that protect
the brain against such environmental assaults, he says.
"The
bottom line is: I wouldn't get too excited about it [the study].
There is increasing evidence that genes determine an individual's
likelihood of developing Parkinson's and other related conditions,"
Feldman says.
Beaman says
the research does not discount the possibility that genetic factors
make some people more susceptible to the bacterium than others.
For every 100 mice injected with the bacteria, only 10 to 20 developed
a disorder, indicating that individual differences play a role,
he says.
"Many
factors are probably involved in causing Parkinson's disease,"
Beaman says. "Studies show that people who develop the disease
have come into contact with something in their environment, which,
combined with the normal aging process, helps to trigger the illness."
Beaman does
not recommend that people stop gardening. "I garden and I
don't worry about the risk. There is some risk in just about everything
you do, whether it's driving or crossing the street. Besides,
Nocardia is also found in house dust," Beaman says.
What To
Do
For more information
on the brain disorder, check the
Parkinson's Disease Foundation, the
National Institute of Neurological Disorders and Stroke or
the Michael
J. Fox Foundation for Parkinson's Research.
Reference
Source 101
For more information on how to prevent other diseases, use
PreventDisease.com's "Quick
Prevention Resources".
|
