HIV infections age the brain abnormally, study finds
HIV infections can age the brain by up to 15 to 20 years, according to an article published in February in the Journal of Infectious Diseases.
To study the effects of HIV on the brain, Beau Ances, assistant professor of neurology at the Washington University School of Medicine, led a team of researchers measuring the rate of blood flow to the brain in 26 HIV-positive and 25 HIV-negative subjects using functional magnetic resonance imaging (fMRI) techniques.
According to Ances, researchers are interested in measuring the rate of blood flow because it is an indicator of one’s biological age.
Since blood carries and distributes necessities to fueling cellular processes such as oxygen and ions to different parts of the body, a faster rate of blood flow correlates with a higher metabolic rate and an enhanced ability to perform tasks and respond to environmental demands.
Blood flow decreases predictably with age, so researchers determined that that the rate of blood flow of HIV-positive subjects was equivalent to that of healthy individuals who were 15 to 20 years older.
This finding, however, does not necessarily indicate that those infected with HIV will have a shorter lifespan compared to their healthy counterparts.
“This [study] is only looking at one time point,” Ances said. “In order to get to really get to the heart of the matter, we need to follow people out for a number of years, and see if, yes, do their brains shrink a lot or change a lot, which then [would lead] to an increased chance of having bad things occur to them.”
While many studies on HIV have been conducted since the discovery of the virus in 1981, this study is unique because it analyzes the effects of the virus on the brain.
The brain, according to Ances, is also a logical area of investigation, because after the virus infects the host, it quickly travels to that organ and stays there for the rest of the host’s life, leaving footprints that are little known to the scientific realm.
“The issue is that we really don’t evaluate that many HIV-positive people by what is happening with their brains,” Ances said.
While the results are only preliminary thus far, researchers hope to ultimately use fMRI to evaluate the efficacy of various therapeutic options for HIV.
Currently, the conventional techniques used to diagnose HIV include analyzing a subject’s white blood cell count—the number of CD4 T cells, to be specific—performing a lumbar puncture and asking the subject to do a pencil-and-paper neuropsychological test.
These techniques may be able to detect the presence of HIV, but they are often time-consuming and invasive.
“If you had a test that was non-invasive, or took a couple of minutes to do—or even less—most people would love to do that [over] any of the other tasks,” Ances said. “The ultimate goal is to eventually have easier ways to access people with common techniques that are available at most MRI scanners.”
In addition to pioneering the forefronts of HIV research, Ances also strongly encourages interested undergraduate students to participate in this type of research, especially in projects that let them see the clinical, human part of the disease.
“If you are doing cell work, it is hard to put a face to the disease when it is multiple steps away,” Ances said. “It is easier to see it when you see a patient who has the disease and you take a picture of their brain.”