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Date Posted: 22:24:14 05/12/01 Sat
In reply to:
Sara
's message, "I ride my horses" on 14:30:08 04/15/01 Sun
Antioxidants Used to Detect
COLOR="#ff0000" SIZE="+2">HIV
COLOR="#ff0000" SIZE="+2">Dementia
By Fran Berger
HealthScout Reporter
5-12-1
Dementia, a severe complication of the HIV, may be detectable,
maybe even reversible, with antioxidant drugs, a new study says.
The researchers say when they added
certain antioxidants to healthy brain cells and placed the cells
in toxic cerebrospinal fluid taken from patients with severe HIV
dementia, the toxicity of the fluid was reversed.
"This is a potentially exciting approach that could serve
as a surrogate marker for dementia," says lead study author
Dr. Avindra Nath, a neurologist at the University of Kentucky
in Lexington.
The research team first looked at how healthy brain cells are
affected by HIV by placing them in the cerebrospinal fluid of
30 HIV patients with different levels of dementia, or brain dysfunction.
The HIV infection decreased the activity of the cells' mitochondria,
or power source. And the damage increased as dementia became severe,
the researchers say.
Mitchondrial functioning provides physical strength and consciousness,
and even subtle problems can cause weakness or cognitive difficulties.
The researchers then added antioxidant drugs to the cultures to
test if mitochondria would be protected from the damaging effects
of the toxic spinal fluid.
Six of seven drugs tested reversed the toxicity of the fluid and
reduced oxidative stress caused by an excess in the number of
harmful substances known as free radicals.
"In the moderate to severe cases, there was a significant
decrease in mitochondrial function. The fluid was more toxic,"
says Nath. The researchers assessed the level of the dementia
by measuring the functional levels of mitochondria, he says.
"We have established an assay that could be used to monitor
patients with HIV," says Nath.
"This study lends support to the notion that reducing oxidative
stress may be important in ameliorating neurologic damage,"
says Dr. Harris Gelbard, a professor neurology and pediatrics
at the University of Rochester Medical Center.
"It represents a confirmation of what might have been expected
. Pre-clinical data suggests that HIV-1 associated dementia is
due in part to oxidative stress interfering with normal communication
in the part of the brain that is most affected by HIV-1-induced
neurotoxins," Gelbard says.
But, Nath says, "We still don't know what products are toxic.
They could be part of the [HIV] virus, but there are a number
of candidates."
Nath says about 20 percent of patients infected with the HIV virus
develop dementia, characterized by both short- and long-term memory
loss, impaired judgment and personality change.
If there is a test that can detect it early on, Nath says "there
should be a slowdown of progression. And if we're lucky, we can
hold it where it is. If you can hold, the brain does have some
ability to heal itself."
Gelbard says it's too early to make such a leap. However, he says,
"We press on with the notion that, much the same as cancer
treatment, a multimodal approach, such as combination chemotherapy,
is more efficacious. Using drugs that have different mechanisms
of action may represent our best chance of successfully prophylaxing
or reversing the damage that HIV-1 infection can cause to the
central nervous system."
The study's results will be presented today at the American Academy
of Neurology's annual meeting in Philadelphia.
What To Do
Read about HIV's assault on the brain at the Society
for Neuroscience.
Learn more about the symptoms of dementia from mentalhealth.com.
And read other HealthScout articles about antioxidants.
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