Featured Research

from universities, journals, and other organizations

Why HIV patients develop dementia

Date:
September 3, 2014
Source:
Ruhr-Universitaet-Bochum
Summary:
Since the introduction of the combination anti-retroviral therapy (cART) in the mid-90s, the life expectancy of HIV patients has significantly improved. As a result, long-term complications are becoming more relevant: almost every second HIV patient is affected by neurocognitive disorders, which can lead to dementia. Researchers have now successfully identified mechanisms how infected cells can activate brain-specific immune cells which subsequently display harmful behaviour and lead to the destruction of neurons.

"HIV-associated neurocognitive disorders" (HAND) include disorders of the cognitive functions, motor capacities as well as behavioural changes. How exactly HAND occur has not, as yet, been fully understood. "Scientists assume that HIV is harmful to cells directly and that is also triggers indirect mechanisms that lead to nerve cell damage," explains Dr Simon Faissner (RUB clinic for neurology, St. Josef-Hospital). The researchers strongly suspect that, once activated in the brain and the spinal cord, immune cells keep up a chronic inflammation level which then results in the destruction of nerve cells. An immune activation in peripheral tissue as well as therapeutic consequences may likewise contribute to nerve cell damage in the brain.

Related Articles


First steps of HIV infection are sufficient

The HI virus overcomes the blood-brain barrier hitchhiking on infected immune cells, the monocytes and probably the T cells. The researchers from Bochum tested the hypothesis that HIV-infected monocytes activate specific immune cells in the brain, the so-called microglial cells. These cells, in turn, respond by releasing harmful substances, such as reactive oxygen metabolites and inflammatory signalling molecules, i.e. cytokines. To test this hypothesis, the researchers developed a cell culture system in which they initially examined the effect of HIV-infected monocytes on microglial cells. The researchers simulated the individual steps of HIV infection and measured the volume of the cytokines released at each stage. Thus, they were able to demonstrate that releasing the viral RNA in the monocytes was a sufficient trigger for maximal microglial activation. Subsequent infection phases -- reverse transcription into DNA and the resulting formation of HIV proteins -- did not augment activation any further.

Released substances result in neuronal cell death

In the second step, they analysed nerve cells from rat brains to determine if the substances released by the microglial cells could lead to cell death. Compared with the control group, the number of cell deaths was indeed twice as high. Studies of liquor cerebrospinalis received from HIV-infected patients have shown a positive correlation with marker of neuronal degeneration in patients who did not as yet present any neurocognitive disorders.

Detailed understanding necessary for therapeutic strategies

"Thanks to our research, we have gained a better understanding of the mechanisms of HIV-associated neurodegeneration," concludes Prof Dr Andrew Chan. "These results are likely to contribute to HAND biomarkers becoming established. In the long term, these data will be used to develop therapeutic strategies aiming at retarding HAND progression in HIV-infected patients." Starting points may include activation of microglial cells -- a method that is applied in other autoimmune diseases of the central nervous system, for example in multiple sclerosis.

Start-up through FoRUM funds

The research, which was initiated following a collaboration between clinics for neurology and dermatology, St. Josef Hospital, as well as the Department for Molecular and Medical Virology, has been made possible through start-up funding provided by the Faculty of Medicine at Ruhr-Universität (FoRUM). The collaboration has evolved into an international consortium of clinics and basic research organisations in Bochum, Langen, Strasbourg and Mailand. One objective of the follow-up study, for which an application for EU funds is pending, is going to be an in-depth analysis of inflammatory processes in the central nervous system. The researchers will attempt to inhibit inflammatory processes with different drugs. They are, moreover, planning to study direct cell-cell interaction by means of state-of-the-art microscopy, in collaboration with the University of Strasbourg.


Story Source:

The above story is based on materials provided by Ruhr-Universitaet-Bochum. Note: Materials may be edited for content and length.


Journal Reference:

  1. Simon Faissner, Björn Ambrosius, irsten Schanzmann, Bastian Grewe, Anja Potthoff, Jan Münch, Ulrich Sure, Thomas Gramberg, Sabine Wittmann, Norbert Brockmeyer, Klaus Überla, Ralf Gold, Thomas Grunwald, Andrew Chan. Cytoplasmic HIV-RNA in monocytes determines microglial activation and neuronal cell death in HIV-associated neurodegeneration. Experimental Neurology, 2014; DOI: 10.1016/j.expneurol.2014.08.011

Cite This Page:

Ruhr-Universitaet-Bochum. "Why HIV patients develop dementia." ScienceDaily. ScienceDaily, 3 September 2014. <www.sciencedaily.com/releases/2014/09/140903091940.htm>.
Ruhr-Universitaet-Bochum. (2014, September 3). Why HIV patients develop dementia. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2014/09/140903091940.htm
Ruhr-Universitaet-Bochum. "Why HIV patients develop dementia." ScienceDaily. www.sciencedaily.com/releases/2014/09/140903091940.htm (accessed October 24, 2014).

Share This



More Health & Medicine News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) — Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com
Ebola Fears Keep Guinea Hospitals Empty

Ebola Fears Keep Guinea Hospitals Empty

AP (Oct. 23, 2014) — Fears of Ebola are keeping doctors and patients alike away from hospitals in the West African nation of Guinea. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Despite Rising Death Toll, Many Survive Ebola

Despite Rising Death Toll, Many Survive Ebola

AP (Oct. 23, 2014) — The family of a Dallas nurse infected with Ebola in the US says doctors can no longer detect the virus in her. Despite the mounting death toll in West Africa, there are survivors there too. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) — Is your child ready? Video provided by Working Mother
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins