A new map of brain tissue in people with HIV shows atrophy in
several areas including a primary neurocognitive control center where shrinkage
and loss of function can be seen in scans before clinical symptoms appear.
The brain map paints a two-stage
model of what exposure to HIV does to the brain, says the senior author, Xiong
Jiang, PhD, director of the Cognitive Neuroimaging Laboratory at Georgetown.
"The drugs we use to keep
HIV at bay work wonderfully well in the body, but they cannot easily reach the
brain due to the blood-brain barrier," says Jiang. "We have long
known about neurocognitive impairment resulting from HIV, but this is the first
time we have a neural model to relate neurocognitive impairment severity to
injury in certain brain structures." HIV-associated neurocognitive
disorders are known as HAND.
The model shows the sweep of
atrophy that occurs as time passes from initial viral infection. It suggests
that early on in HIV+ disease, the virus affects the frontal lobe, considered
to be the essential hub of brain networks, responsible for such high-level
tasks as attention and executive and cognitive functioning. By contrast, the
injury to the caudate/striatum area, a subcortical region and part of the motor
and reward system, becomes more prominent when individuals develop clinical
HAND symptoms.
"There is a strong desire
for a neural model of HAND severity, which currently is solely defined by
neurobehavioral assessments using standard neuropsychological tests," he
says. "This model, while highly simplified, might have the potential to
help to develop targeted treatment, which in turn might be more effective."
The researchers found that the
frontal region (including anterior cingulate cortex, or ACC) is the most
frequently affected brain region in HIV+ adults, whereas the neural injury to
the caudate/striatum was consistently linked to neurocognitive impairment.
These results suggest a two-stage
model of HAND in the context of brain atrophy, with a frontal/ACC stage that
links to HIV disease and likely other comorbidities, such as substance abuse,
and a caudate/striatum stage that links to neurocognitive impairment. "These
two areas likely play different roles in HAND," Jiang says.
"It is our theory, and
others, that the frontal/ACC area damage is due to a number of factors, but
which importantly includes damage to the dopaminergic region," he says.
"Also, we believe the caudate might be one of the key HIV reservoirs in
the brain.
Source: Georgetown University Medical Center
After the magnificent success of World Congress on HIV AIDS STD and STI which was held in Valencia, Spain during April 23-25, 2018, we are proudly announcing the 2nd World Congress on HIV AIDS STD and STI during September 09-10, 2019 at Bangkok, Thailand.
HIV AIDS Congress 2019 is the best platform for interdisciplinary researchers, practitioners, academics, research scientists, students and healthcare industrialists to meet, share, discuss and exchange the most recent relevant experiences in their practices. This would centre on presentations and discussions on research oriented results on all aspects of HIV and AIDS. Consequently, it will provide the necessary platform to both transfer and exchange relevant knowledge in the field of HIV and AIDS.
