By David Douglas
NEW YORK (Reuters Health) - In people with HIV, gray-matter atrophy is most prevalent in the frontal region, including the anterior cingulate cortex (ACC), and the caudate/striatum region, new research shows.
Gray-matter atrophy is often seen in people living with HIV, but whether some areas are more vulnerable than others has been unclear, Dr. Xiong Jiang and colleagues from Georgetown University Medical Center, in Washington, D.C., note in Human Brain Mapping, online March 28.
To investigate the possible neural profiles of HIV-associated neurocognitive disorders (HAND) severity, the team examined findings of 25 studies involving 1,370 people with HIV and 889 controls.
Using a new meta-analysis technique called colocalization-likelihood estimation, they found that frontal atrophy was associated with HIV-disease and consistently differentiated patients from controls. Caudate/striatum atrophy, on the other hand, was associated with neurocognitive impairment.
"Caudate/striatum was shown to be the most affected region in the pre-cART (combination antiretroviral therapy) era," Dr. Jiang told Reuters Health by email. "Interestingly, here we found a direct link between caudate/striatum atrophy and cognitive impairment."
This suggests that "HAND in the post-cART era might share some neuropathogenesis with HAND in the pre-cART era, i.e., a toxicity effect due to ongoing viral replication and neuroinflammation in the brain, among other factors. So controlling viral replication/eradicating virus from the brain might still be the best approach to treat HAND."
He added, "Frontal/ACC injury is highly prevalent in HIV+ adults, suggesting a high prevalence of mild/subtle impairment to cognitive functions associated with these regions, such as multitasking, cognitive control, and other high level executive functions."
Dr. Jiang pointed out that "it is known that aging has a significant impact on frontal/ACC function as well, so older HIV+ adults will likely be at an elevated risk due to a double-hit from aging and HIV-disease. With a rapidly aging HIV+ populace, this might increasingly become a significant problem."
In addition, the researchers developed a hypothesized neural model of HAND severity. "One prediction of the neural model," said Dr. Jiang, "is that a suboptimal viral suppression or a rebound in viral load might have a stronger impact on caudate/striatum than frontal/ACC."
However, Dr. Jiang stressed that "this neural model represents a first step in this exciting direction and rather than make conclusions" it should be treated with caution. "But the model itself and the findings have interesting and potentially important implications."
Hum Brain Mapp 2019.