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Antioxidants Used to Detect HIV Dementia

Could help prevent it too, study says

FRIDAY, May 11 (HealthScout) -- Dementia, a severe complication of the HIV virus, 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

And read other HealthScout articles about antioxidants.

SOURCES: Interviews with Avindra Nath, M.D., neurologist, University of Kentucky, Lexington, and Harris A. Gelbard, M.D., Ph.D., professor of neurology and pediatrics, University of Rochester Medical Center; American Academy of Neurology
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