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 A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich

nachricht New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin

All articles from Life Sciences >>>

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

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>