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| Pennell and his group report that levels of dieldrin in the
autopsied brain
| tissue of 14 Parkinson's patients were more than three times
those of 12
| similarly aged people who didn't have the disease.
| The researchers also exposed mice to repeated low-level doses
of dieldrin to
| simulate environmental exposure that humans might encounter.
The mice's brain
| tissue showed significant reductions in the uptake of dopamine,
a
| neurotransmitter. And, levels of carbonyls -- a marker of
oxidative stress --
| were increased substantially in the brain of dieldrin-treated
mice, Pennell
| reported.
| "Our research shows that elevated levels of dieldrin are
associated with
| Parkinson's disease in humans, which is supported by an animal
model study
| that correlates low-level exposure to dieldrin with early
markers of
| Parkinson's disease," he explained.


Interesting, but puzzling.  (Sorry for the delay in responding.)

Generally, organochlorine pesticides like dieldrin are stored in
the fat, not the brain.  Thus, the people with PD and higher
levels of dieldrin in their brains may NOT have been exposed to
higher levels of the pesticide.  Rather, something about PD may
have caused the dieldrin to be released from the fat.

Also, given the very small numbers of people, it would be
interesting to know their causes of death.  In particular, might
the PD patients have happened to have lost a lot of weight
shortly before their deaths?  This would have released stored
dieldrin from their fat.

It is not news that organochlorine pesticides are neurotoxins.
They are designed to kill bugs by messing up their
neurotransmitters.  The fact that dopamine is affected is not
surprising.

It gets pretty complicated!


----- Original Message -----
From: "M.Schild" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, September 16, 2006 2:16 AM
Subject: dieldrin and PD


|  Banned Pesticide May Be Linked to Parkinson's Disease
| 09.15.06, 12:00 AM ET
| THURSDAY, Sept. 14 (HealthDay News) -- A now-banned pesticide
that still
| lingers in the environment could be damaging human brain cells
and prompting
| the onset of Parkinson's disease, a new study suggests.
| Animal and human cadaver studies appear to link exposure to
dieldrin, an
| organochlorine pesticide, with Parkinson's disease, researchers
say.
| "We can't say at this point that pesticides cause Parkinson's
disease, but we
| feel it accelerates the process," said Kurt Pennell, an
associate professor
| at the School of Civil and Environmental Engineering at Georgia
Institute of
| Technology, Atlanta.
| Pennell and his group report that levels of dieldrin in the
autopsied brain
| tissue of 14 Parkinson's patients were more than three times
those of 12
| similarly aged people who didn't have the disease.
| The researchers also exposed mice to repeated low-level doses
of dieldrin to
| simulate environmental exposure that humans might encounter.
The mice's brain
| tissue showed significant reductions in the uptake of dopamine,
a
| neurotransmitter. And, levels of carbonyls -- a marker of
oxidative stress --
| were increased substantially in the brain of dieldrin-treated
mice, Pennell
| reported.
| "Our research shows that elevated levels of dieldrin are
associated with
| Parkinson's disease in humans, which is supported by an animal
model study
| that correlates low-level exposure to dieldrin with early
markers of
| Parkinson's disease," he explained.
| The researchers presented their findings Thursday at the
American Chemical
| Society annual meeting, in San Francisco.
| Dieldrin was banned in the 1987 but, Pennell said, "It's very
persistent and
| remains in the ground. It accumulates in lipid tissues,
including the brain."
| Parkinson's disease, a neurodegenerative disorder, affects an
estimated
| 500,000 people in the United States, and about 50,000 new cases
are reported
| annually. These numbers are expected to increase as the
population ages. The
| disorder appears to be slightly more common in men than women,
and the
| average age of onset is about 60, according to the U.S.
National Institute of
| Neurological Disorders and Stroke.
| Prior epidemiological and laboratory studies have suggested a
link between
| chronic exposure to persistent organic pollutants, such as
polychlorinated
| biphenyls (PCBs), and Parkinson's disease.
| Dr. Rajesh Pahwa is director of the Parkinson Disease and
Movement Disorder
| Center at the University of Kansas Medical Center, in Kansas
City. He said
| that while the study isn't "major news, it is interesting in
that it shows
| postmortem Parkinson's disease patients' brains had higher
levels of
| pesticide compared to normal controls. And this study has
confirmed other
| work correlating pesticide exposure with the illness."
| But, Pahwa added, "This is a small [study] and questions
remain. For example,
| were the Parkinson's brains more exposed to these chemicals or
were the
| Parkinson's patients unable to clear or metabolize the
dieldrin?"
| Pahwa suggested that the causes of Parkinson's are most likely
complex, and
| may be due to a combination of genetic and environmental
factors. "Maybe
| these studies could lead us to a biomarker for the disease or
for people who
| are being exposed to the disease," he said.
| Pennell said, "It is hard to say that exposure to dieldrin is
causal, but as
| people live longer they're more likely to get Parkinson's."
That means
| exposure becomes more relevant. "Baby boomers could have been
exposed to
| these chemicals before they were banned and now as they age, we
could see
| more disease."
| Dieldrin and other banned pesticides should dissipate in the
environment
| during the next few decades and become less of a factor in the
development of
| Parkinson's disease, said study researcher Gary Miller, an
associate
| professor of environmental and occupational health at Emory
University.
| "Today, people are being exposed to much lower levels of
pesticides than
| people were 30 or 40 years ago," Miller said in a prepared
statement. "I
| would predict that over the course of the next several decades
that we will
| see a decrease in the incidence of Parkinson's disease."
| More information
| For more on the possible link between pesticides and
Parkinson's disease,
| visit the Harvard School of Public Health.
|
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