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 A promising target for kidney fibrosis
21.04.2017 | Brigham and Women's Hospital

nachricht Stem cell transplants: activating signal paths may protect from graft-versus-host disease
20.04.2017 | Technische 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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>