HIV directly impacts brain in early stages of infection

November 30, 2017, Stellenbosch University
HIV infecting a human cell. Credit: NIH

Stellenbosch University (SU) researchers have discovered that the human immunodeficiency virus (HIV) directly impacts the brain in the early stages of the infection.

It has long been known that many people with HIV also experience negative cognitive symptoms, such as depression, forgetfulness, etc. However, it was unclear whether it was caused by such patients' physical illness, or whether the HI virus had a direct effect on the .

"Our research shows that HIV does have an impact on the brain and that these low-grade cognitive symptoms are likely not just function loss due to patients feeling sick, tired or depressed," says Dr Stéfan du Plessis, lead author of a series of articles about the research published in AIDS and other international journals.

Using functional (fMRI) - a type of brain scan that shows how blood flows to certain parts of the brain when someone is performing certain tasks or is experiencing certain emotions - Du Plessis and his team compared the brain activity of people with HIV to those without HIV while they performed certain tasks designed to stimulate specific regions of the brain. HIV-positive study participants were in good physical and mental health, did not abuse drugs, and had not yet started on antiretroviral treatment (ART).

They found that these participants had a decreased in the striatal region of the brain while performing tasks involving higher motor functions. They also observed little action and blood flow to the nucleus accumbens of HIV-positive patients while performing a task involving a monetary reward. This section of the brain is involved with aspects concerning motivation, apathy and enthusiasm for life.

"The fMRI scans show how the HI virus affects important parts of the brain involved with motivation. We theorise that this could happen to such an extent that patients are often simply not motivated enough to take their medication, or even get out of bed," explains Du Plessis. He conducted the research as part of his PhD in Psychiatry and was the first person to obtain a PhD at SU's Faculty of Medicine and Health Sciences that focused on fMRI.

Finally, the researchers also studied the structure of the frontal cortex, a brain region that is known to atrophy in the context of HIV. They discovered a link between the levels of atrophy and brain functional impairment - the thinner the actual frontal lobe was, the lower the levels of function.

"The study highlights a previously unknown functional effect that HIV has on the brain. We hope that these results will stimulate further studies to test the effects of ARVs, or other interventions, that could improve brain function and therefore the lives and well-being of patients with HIV," says Du Plessis.

Earlier studies have shown that up to 50% of people with HIV may suffer from some form of cognitive impairment, ranging from subtle impairment detectible only through sophisticated cognitive tests, to severe psychosis.

Prior to the introduction of ART many patients developed severe HIV-related dementia. ART has markedly improved the symptoms of dementia in HIV-positive people.

Explore further: Brain disconnections may contribute to Parkinson's hallucinations

Related Stories

Brain disconnections may contribute to Parkinson's hallucinations

September 27, 2017
Researchers have found that disconnections of brain areas involved in attention and visual processing may contribute to visual hallucinations in individuals with Parkinson's disease, according to a new study published online ...

Manipulating brain network to change cognitive functions: New breakthrough in neuroscience

August 7, 2017
When an electric circuit breaks down, we can repair it by restoring connections in the circuit. Is it possible to restore the connections in our brain? And by doing so, is it possible to restore declining cognitive functions? ...

Researchers find functional change in brains of patients with type 1 diabetes

June 28, 2017
Researchers from the Institute of Neuroscience and the Institute of Complex Systems (UBICS) of the University of Barcelona have identified differences in the pattern of the neurofunctional activation in patients with type ...

Study describes changes to structural brain networks after radiotherapy for brain tumors

June 26, 2017
Researchers compared the thickness of brain cortex in patients with brain tumors before and after radiation therapy was applied and found significant dose-dependent changes in the structural properties of cortical neural ...

How insulin in the brain may suppress the subjective feeling of hunger

June 26, 2017
Insulin in the brain may help regulate the hunger sensation and improve functional connectivity in the default-mode network (DMN), as well as in the hippocampus and hypothalamus. This is the finding of a new study by researchers ...

Structural deficits may explain mood-independent cognitive difficulties in bipolar disorder

November 1, 2016
A new study in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging using magnetic resonance imaging (MRI) reports a link between reduced functional activation and reduced cortical thickness in the brains of patients ...

Recommended for you

Long-acting injectable implant shows promise for HIV treatment and prevention

October 9, 2018
A persistent challenge in HIV/AIDS treatment and prevention is medication adherence – getting patients to take their medication as required to get the best results.

Scientists develop rapid test for diagnosing tuberculosis in people with HIV

October 8, 2018
An international team that includes Rutgers scientists has made significant progress in developing a urine diagnostic test that can quickly, easily and inexpensively identify tuberculosis infection in people also infected ...

Researchers uncover new role of TIP60 protein in controlling tumour formation

October 8, 2018
Scientists from the Cancer Science Institute of Singapore (CSI Singapore) at the National University of Singapore (NUS) have discovered a new molecular pathway that controls colorectal cancer development, and their exciting ...

Combination therapy targets latent reservoir of HIV

October 3, 2018
With more than 35 million people worldwide living with the virus and nearly 2 million new cases each year, the human immunodeficiency virus (HIV) remains a major global epidemic. Existing antiretroviral drugs do not cure ...

Anti-integrin therapy effect on intestinal immune system in HIV-infected patients

October 3, 2018
In a study published today in Science Translational Medicine, Mount Sinai researchers describe for the first time a mechanism that may shrink collections of immune cells in the gastrointestinal (GI) tract, called lymphoid ...

No 'reservoir': Detectable HIV-1 in treated human liver cells found to be inert

October 1, 2018
In a proof-of-principle study, researchers at Johns Hopkins report that a certain liver immune cell called a macrophage contains only defective or inert HIV-1 copies, and aren't likely to restart infection on their own in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.