Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

AIDS inflicts specific pattern of brain damage, reveals UCLA/Pittsburgh imaging study

11.10.2005


Antiretroviral drugs don’t halt damage



A new UCLA/University of Pittsburgh imaging study for the first time shows the selective pattern of destruction inflicted by AIDS on brain regions that control motor, language and sensory functions. High-resolution 3-D color scans created from magnetic resonance images (MRI) vividly illustrate the damage.

Published Oct. 10 by the online Proceedings of the National Academy of Sciences, the research offers a new way to measure the impact of AIDS on the living brain, and reveals that the brain is still vulnerable to infection when patients are receiving highly active antiretroviral therapy (HAART).


"Two big surprises came out of this study," explained Paul Thompson, Ph.D., first author and associate professor of neurology at the David Geffen School of Medicine at UCLA. "First, that AIDS is selective in how it attacks the brain. Second, drug therapy does not appear to slow the damage. The brain provides a sanctuary for HIV where most drugs cannot follow."

Thompson’s laboratory used a new 3-D brain-mapping technique developed at UCLA to analyze the MRIs of 26 people diagnosed with AIDS, and then compared the scans to those of 14 HIV-negative people. The brain scans measured the thickness of gray matter in various regions of the cerebral cortex.

The University of Pittsburgh diagnosed and scanned the AIDS patients; all 26 subjects had lost at least half of their T-cells, the immune cells targeted by HIV. None had experienced AIDS-related dementia, and 13 were on HAART.

The striking differences between the AIDS patients’ and the control subjects’ brain scans were easy to see on the detailed 3-D images. Areas of tissue loss glowed red and yellow, while intact regions shone blue and green.

The researchers were surprised to discover that AIDS consistently injured the brain’s motor, language and judgment centers, but left other areas alone. Specific patterns of tissue damage directly correlated with patients’ physical and mental symptoms, including impaired motor coordination and slowed reflexes.

"The brain scan really catches AIDS red-handed, allowing us to see precisely where the damage is," Thompson observed. "For the first time, we can understand why motor skills deteriorate with AIDS, because the virus attacks the motor centers on top of the brain."

"We saw up to a 15-percent tissue loss in the brain centers that regulate motor skills, such as movement and coordination," added Thompson. "This helps explain the slowed reflexes and disruption of balance and gait that often affect people with early AIDS."

The UCLA team also linked thinning of the language cortex and reasoning center to depletion of T-cells from the immune system. The finding may shed light on why AIDS is often accompanied by mild vocabulary loss, judgment problems and difficulty planning. As the disease advances, these symptoms can worsen into memory loss and dementia similar to Alzheimer’s disease.

"Tissue loss follows T-cell loss, meaning that people with poor immune function also show severe brain damage," explained Thompson. "This was a revelation. We used to consider these separate phenomena, because HIV harms the brain and immune system in different ways. Now we see they are intrinsically linked."

"This is an exciting finding, not only because we can now see the effects of HIV/AIDS on the cortex, but also because it reinforces the importance of using sophisticated neuroimaging measurements as biomarkers for the effects of the virus on the brain," said James Becker, Ph.D., professor of psychiatry, neurology and psychology at the University of Pittsburgh. "Techniques such as these may also prove useful in evaluating the effects of HIV-medications on the brain."

The researchers were most startled to see no difference in tissue loss between the patients taking HAART and those who were not.

"This was the most terrifying aspect of our findings," said Thompson. "Even though antiretroviral drugs rescue the immune system, AIDS is still stalking the brain. A protective blood barrier prevents drugs from entering the brain, transforming it into a reservoir where HIV can multiply and attack cells unchecked."

The scientists hail brain imaging as a useful method for monitoring AIDS and evaluating new drugs’ effect on disease progression. The technique can be powerfully applied to gauge patients’ response to therapy, even before the onset of dementia or opportunistic infections.

"Brain mapping can help physicians monitor patients with more accurate detail than they can obtain by counting T-cells," said Thompson. "The scans also can test new drugs’ ability to penetrate the brain during clinical trials."

One in 100 people aged 15 to 49 is infected with HIV, the fourth leading cause of death worldwide. In 2004, 40 million people were living with the disease. Forty percent of AIDS patients suffer from progressive neurological symptoms, typically leading to death.

Elaine Schmidt | EurekAlert!
Further information:
http://www.mednet.ucla.edu

More articles from Health and Medicine:

nachricht Organ-on-a-chip mimics heart's biomechanical properties
23.02.2017 | Vanderbilt University

nachricht Researchers identify cause of hereditary skeletal muscle disorder
22.02.2017 | Klinikum der Universität München

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>