HIV dementia linked with brain dopamine levels

HIV patients with early signs of dementia have significantly depleted levels of the brain chemical dopamine, researchers at the Brookhaven National Laboratory in Upton, N.Y., report in the September issue of the U.K. journal Brain. Brain scans of 15 HIV patients, some of whom were exhibiting early signs of dementia, showed that dopamine-producing cells were 12% to 20% lower than in HIV-negative patients. The researchers' findings support data from studies of the brains in cadavers of HIV patients that showed lower levels of dopamine-producing cells. "This study clearly demonstrates that HIV infection damages dopamine-associated brain cells, and provides a pathway for developing more effective treatments," says Nora Volkow, National Institute on Drug Abuse director and coinvestigator on the study. But current dopamine-enhancing medicines might not prove to be the best course of action, the researchers say. Laboratory and animal tests show these drugs make dopamine-producing brain cells more vulnerable to HIV infection, and as such, new treatments are needed to help prevent the development of dementia in HIV-positive adults. It also may be possible to combine current dementia treatments, commonly used to treat Parkinson's disease, with antioxidants to lower the HIV infection risks for the dopamine cells.