Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scavenger cells could be key to treating HIV-related dementia

15.09.2005


Understanding macrophages could lead to ways to prevent HIV-associated dementia



Bacteria-eating cells that generally fight infection may cause dementia in HIV patients, University of Florida and University of California at San Francisco researchers have found.

Macrophages, long-living white blood cells often considered the scavengers of the immune system, actually may damage a part of the brain where many memories are stored in their attempt to attack the virus there, according to findings reported in the Journal of Virology this month.


Researchers found that HIV-infected macrophages in the brain continuously travel to the temporal lobe, a part of the brain Alzheimer’s disease often damages. Because the virus mutates nearly 100 times faster in the temporal lobe than other parts of the brain, attacking macrophages migrate there in a constant stream, causing harmful inflammation.

Nearly 15 percent of HIV patients develop dementia as their disease progresses. But understanding the routes macrophage cells take in the brain could help researchers find ways to block the migration and prevent HIV-associated dementia, said Marco Salemi, Ph.D, a UF assistant professor of pathology and immunology and an author of the study.

"In a way, it’s not the virus that directly causes the dementia," Salemi said. "It’s the fact that there is this continuous migration of infected macrophages to the temporal lobe. The virus mutates much faster there, the macrophages keep accumulating and keep creating this inflammation that leads to dementia."

Macrophages also may explain why current drugs cannot kill the virus that causes AIDS.

Researchers have known for years how HIV replicates in T cells, also part of the immune system. But most are just beginning to understand how the virus affects macrophages, said Michael S. McGrath, M.D., Ph.D, a UCSF professor of pathology and laboratory medicine who co-authored the study.

"It’s likely the oldest (form of the) virus lives in a macrophage in the brain and most virus strains evolve from that," McGrath said. "Imagine having cells, already infected, that live as long as you do."

Current antiretroviral drugs block HIV from replicating in new T cells, but don’t kill the virus in infected macrophages. And the drugs cannot stop the virus from evolving into new forms, McGrath said. Because the virus mutates faster than other cells in the body, it also can develop resistance to these drugs, Salemi said.

Even the HIV already in an infected person’s brain is not one single virus, but rather populations of slightly different viruses that infect different parts of the brain, the findings show.

"We agree there are different strains that populate different regions of the brain," said Francisco Gonzalez-Scarano, M.D., chairman of the University of Pennsylvania neurology department. "We’ve done similar studies in monkeys."

To obtain their findings, the researchers studied different regions of the brain of a person who died with HIV-associated dementia using specimens from the AIDS and Cancer Specimen Resource at UCSF. They also used a new computer-based research tool to study the results. Dubbed phylodynamic analysis, this new method links traditional ways of studying the virus to give researchers a more comprehensive understanding, which Salemi says is crucial to analyzing the ever-changing disease.

"If we really want to understand what happens to a person infected with this disease, we need to develop new tools," he said. "We can put together all these different resources and describe how the virus changes over time and try to understand why this particular damage happens"

But these results are just a first step, Salemi said. The team is now analyzing brains from 10 people, some who died with HIV-associated dementia and others who did not.

The well-known cocktail of antiretroviral drugs prescribed to most HIV patients has cut the number of HIV-associated dementia cases reported each year, Gonzalez-Scarano said. However, this is because the drugs slow the progression of the disease, he said. Patients still have the same chance of developing dementia later, as the disease advances.

That’s one of the reasons why the researchers say developing drugs that target macrophages as well as T cells is important. These drugs could provide better treatments for dementia and potentially lead to a way to "eradicate HIV-1 infection," the study states.

"You can’t cure (HIV) with antiretroviral therapy (alone)," McGrath said.

April Frawley Birdwell | EurekAlert!
Further information:
http://www.health.ufl.edu

More articles from Life Sciences:

nachricht Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>