Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study shows role of disease-fighting cells in HIV-related neurological damage

12.05.2015

Findings add to evidence macrophage accumulation is central to brain injury

Despite symptom-stifling anti-retroviral drugs, as many as half of all patients living with HIV experience neurological damage tied to chronic inflammation in the brain fueled by the body's own immune defenses.


Dyes illuminate macrophage and monocyte cells as they arrive in the brain, where their presence is tied to neurological damage in people otherwise living symptom-free with HIV. By using different colored dyes to tag these disease-fighting cells, researchers have developed a clearer picture of how and when macrophages and monocytes accumulate in different parts of the brain during stages of HIV infection and the onset of AIDS. The findings, reported in the American Journal of Pathology, add new evidence about the role of these cells in AIDS-related dementia and other illnesses.

Credit: Amer. Journal of Pathology

In an effort to understand why patients who appear virus free are afflicted with AIDS-related dementia and other illnesses, researchers have focused on disease-fighting cells, called macrophages and monocytes, as they traffic throughout the body and into the brain.

But little has been known about the timing and dynamics behind these types of white blood cells as they invade the central nervous system during the initial stages of HIV infection or at the onset of AIDS.

A new investigative approach in SIV-infected rhesus monkeys has yielded fresh clues that show the caustic interplay between macrophage and monocyte traffic in the central nervous system and the onset of HIV infection and the formation of brain lesions tied to neurological damage, according to a new report in the online edition of the American Journal of Pathology.

Researchers from Boston College, the University of Florida and Tulane University Health Science Center report macrophages accumulate in different parts of the brain during different stages of initial infection, a finding that clarifies the spread of infection to the brain is a multi-layered and dynamic process.

"This type of approach allowed us to label macrophages in the perivascular space in the brain to identify macrophage and monocyte traffic to the brain in the early, mid and late stages of infection," said Boston College Professor of Biology Kenneth Williams, the senior author of the report. "We now know what cells bring the virus to the brain and what cells contribute to neurological damage in the brain, as well as the timing of the entry of these cells and when the pathologic virus enters. These are two big questions researchers have had."

The researchers tagged monocytes, destined to enter the brain, in bone marrow with a biochemical marker known as BrdU and also used a series of different color dyes to label macrophages as they entered the central nervous system at different times in infection, including early, mid and terminal states. As infection progressed, the researchers found MAC387 macrophages accumulated in the meninges and choroid plexus in early-stage brain infection. Later on, MAC387 macrophages were found in perivascular spaces that surround arteries and veins in the brain, as well as at sites where brain lesions would form.

Another macrophage, known as CD163 macrophages, was traced to perivascular space and brain lesions during the late stage, the team reports. Late in infection, the volume of macrophages entering the brain was nearly three times as great as during early-stage infection.

"An important question researchers have is what drives the pathology and the resulting damage in the brain?" said Williams. "Is it the virus itself or macrophage and monocyte cells? What we found is that these cells that arrive late with the development of AIDS have a 2.9-fold higher percentage of being infected with the virus. So there is a dramatic increase in the viral load as infection progresses that correlates to macrophage accumulation."

Turning their attention to lesion formation, the researchers discovered that greater than 80 percent of the macrophages found in the lesions were present in the brain prior to lesion formation. The surprising finding suggests the cells in the lesions migrated from non-lesion sites in the brain rather than from outside the brain.

"Brain lesions are central to understanding what causes AIDS-related dementia," said Williams. "In early stages of infection, we could see two or three macrophages scattered along the vessel. By the late stage, when lesions appeared, there were 30 to 50 at the site. What we found is that a majority of the cells in the lesions were present in the brain at an early stage. So these macrophages are migrating from the brain to the lesion sites, which shows a complex and dynamic level of activity."

Media Contact

Ed Hayward
ed.hayward@bc.edu
617-552-4826

 @BostonCollege

http://www.bc.edu 

Ed Hayward | EurekAlert!

Further reports about: HIV brain lesions central nervous system damage macrophage macrophages nervous neurological

More articles from Life Sciences:

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

nachricht Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>