HIV Digest	HIV Digest Archive

Scientists have detected depletion of the brain chemical dopamine in AIDS patients living with early indications of dementia. Dopamine depletion is more commonly associated with Parkinson's, not dementia.

The scientists compared brain scans of 15 AIDS patients, some of whom had signs of dementia, with those of 13 HIV-negative volunteers. The results suggest that AIDS patients with dementia have lost 12-20 percent of their dopamine cells. Before symptoms develop, Parkinson's patients lose 80-90 percent of dopamine cells in a key area of the brain that regulates movement. In addition to tremors and rigidity, Parkinson's patients often experience mild attention and thinking problems, and they are at high risk for depression. Recent cadaver studies of AIDS patients' brains have also noted a loss of dopamine cells.

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The new finding provides insight into some AIDS patients' complaints of memory and attention deficits. It also offers a potential treatment in the dopamine-boosting medications used to treat Parkinson's.

However, test-tube and animal studies suggest that dopamine-enhancing medicines like L-Dopa may actually leave the brain's dopamine cells more vulnerable to HIV, according to lead author Dr. Gene-Jack Wang, who suggested adding antioxidants to the Parkinson's drugs reduces this risk.

"It is a dementia, but it is very different from Alzheimer's," Wang said. "This is a unique form of dementia. Doctors must appreciate that the treatments will be vastly different from the ones used in Alzheimer's patients."

Editor's Note: from Newsday