EMBARGOED UNTIL 4 P.M. ET, FRIDAY, SEPTEMBER 10, 1999
For more information contact: Julie Gilber
(651) 695-2763, [email protected]
Early Treatment Improves HIV-Related Dementia
ST. PAUL, MN -- Early stages of HIV-related dementia may be treatable and reversible, according to a study published in the September 11 issue of Neurology, the American Academy of Neurology's scientific journal. Highly active antiretroviral therapy, frequently called the "AIDS cocktail," can reverse chemical changes and brain injury associated with HIV. The cocktail is a potent combination of three or more medications effective for preventing the HIV virus from multiplying.
Patients infected with the human immunodeficiency virus (HIV) often develop cognitive abnormalities or dementia due to the infection's direct and indirect effect on the body's central nervous system.
"Although the exact mechanism is not completely understood, some of the proteins on the virus itself are toxic to brain cells, causing direct injury to the brain," said study author and neurologist Linda Chang, MD, with the University of California, Los Angeles. "In addition, the body and the brain's inflammatory response to HIV, which is mediated by chemicals released by white blood cells in the body and by glial cells in the brain, can also cause injury to brain cells."
Because early HIV-related dementia is associated with chemical rather than structural changes in the brain, early detection and treatment while these changes may still be reversible could prevent permanent or severe brain damage.
"We know that patients with HIV dementia have elevated levels of choline-containing compounds (released when cell membranes are injured) and a chemical called myo-inositol in their brains," said Chang. "Since myo-inositol is thought to be present only in the brain's glial cells, elevated levels probably represent an increased number of reactive glial cells, due to a reactive process in the brain regions associated with the HIV infection."
The researchers monitored 16 HIV patients with mild dementia prior to and at least three months following treatment with highly active antiretroviral therapy. Their results were compared with 15 HIV-negative healthy volunteers. Proton magnetic resonance spectroscopy (a brain scan similar to a MRI) was used to evaluate the chemical composition of selected brain regions.
The 14 patients who continued with the therapy had improved levels of dementia, with most decreasing on a rating scale from clinical mild dementia to very slight dementia. The patients also showed significant reversals of their brains' earlier chemical changes, including an average decrease of 14 percent of initially elevated myo-insitol levels.
"These patients had an initially elevated level of myo-insitol of 15 to 20 percent and the level decreased to approaching normal in the majority of patients after treatment," Chang said. "This suggests that the glial cells in the brain were no longer showing a strong reactive process, probably due to a significant decrease of the virus particles in the brain as a result of the treatment."
Two patients were unable to tolerate the therapy due to side effects including nausea, diarrhea and headaches. They showed progressive cognitive decline and further elevation of choline-containing compounds and myo-inositol in the brains' frontal white matter.
"Highly active antiretroviral therapy has significantly improved the survival of AIDS patients," said Chang. "This preliminary study shows that the therapy improves brain injury associated with HIV dementia in addition to systemic measures of HIV infection such as plasma viral load.
"With proton magnetic resonance spectroscopy we can assess chemical abnormalities associated with the brain infection due to HIV without having to perform a brain biopsy. Since the test is non-invasive and has no side effects, it can be performed repeatedly to determine whether the medications are still effective in the long term, since some of the patients may eventually develop resistance to the medications."
The American Academy of Neurology, an association of more than 16,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research.
-end-
RSS