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HIV Disrupts Blood-Brain Barrier Which May Lead to Neurological Deficits

Discussion in 'Other Health News and Research' started by Waverunner, Jul 6, 2011.

  1. Waverunner

    Waverunner Senior Member

    Awesome study which perfectly helps to explain how a virus can cause neurological deficits. The question however: When will they transform their knowledge into working treatments? I'm 100% sure that all kinds of people with different diseases will benefit from treatments that cure BBB disruptions.


    ScienceDaily (June 28, 2011) HIV weakens the blood-brain barrier -- a network of blood vessels that keeps potentially harmful chemicals and toxins out of the brain -- by overtaking a small group of supporting brain cells, according to a new study in the June 29 issue of The Journal of Neuroscience. The findings may help explain why some people living with HIV experience neurological complications, despite the benefits of modern drug regimens that keep them living longer.

    Standard antiretroviral treatments successfully suppress the replication of HIV and slow the progression of the disease. Yet recent studies show 40 to 60 percent of patients on such therapy continue to experience mild to moderate neurological deficits -- including memory loss and learning challenges.
    In the new study, Eliseo Eugenin, PhD, of Albert Einstein College of Medicine, found that HIV infection in a small number of supporting brain cells called astrocytes breaks down the blood-brain barrier, despite low to undetectable viral production. Under normal conditions astrocytes help bolster the blood vessels comprising the barrier.
    To test if HIV interfered with this support system, Eugenin and his colleagues built a model of the blood-brain barrier using human cells in the laboratory. In a previous study, the researchers found HIV infects around 5 percent of astrocytes. In the current study, the researchers found the presence of HIV in a similar percentage of astrocytes led to the death of nearby uninfected cells and made the barrier more permeable.
    As the neighboring cells died, however, HIV-infected astrocytes survived. Astrocytes exchange chemical signals through specialized molecules called gap junctions. When they were blocked in the model, it prevented the changes to the blood-brain barrier and nearby cells, suggesting the infected astrocytes relay toxic signals to neighboring cells through the gap junctions.
    "Our results suggest HIV infection of astrocytes may be important in the onset of cognitive impairment in people living with the disease," Eugenin said. "New therapies are needed that not only target the virus, but also to stop the virus from spreading damage to other uninfected brain cells."
    Eugenin's group also analyzed the brain tissue of macaque monkeys infected with the simian form of HIV. Similar to what they saw in the human blood-brain barrier model, the researchers found uninfected cells in contact with HIV-infected astrocytes died, while infected astrocytes remained alive as the disease progressed.

    "Researchers have been stymied to explain why HIV-associated neurological complications persist, despite potent combination antiviral therapies that have dramatically improved health and survival," said Igor Grant, an expert who studies HIV-associated neurocognitive impairment at the University of California, San Diego. "This study provides a possible explanation indicating that minute numbers of infected astrocytes can trigger a cascade of signals that could open the brain to various toxic influences."
    The findings open up the possibility of developing new therapeutic approaches that block or modify the transmission of signals from the HIV-infected astrocytes, added Grant, who was not affiliated with the study.
  2. Enid

    Enid Senior Member

    Yes I quite agree Waverunner - personally never doubted whatever pathogen crossed the BBB - (extreme end of the ME/CFS spectrum with encephalitis at the worst stage).
  3. Overstressed

    Overstressed Senior Member

    Sometimes I get so tired of research in general... Some time ago, a German researcher discovered why so many CD4 cells 'died' despite the fact HIV infected a small number of cells. It kills these cells indirectly, by releasing/creating a protein, Nef I think.

    I'm sure, these astrocytes die by the same mechanism, perhaps by means of another protein. You wonder why the HIV puzzle is not solved after more than 3 decades, it's because they ask the same questions again, over and over and over...

  4. Waverunner

    Waverunner Senior Member

    Ye, the problem in my eyes is that we have endless amounts of research for HIV. No human is able to work through all that stuff but as long as the money flows we will have similar studies over and over again. If only 1% of the money directed towards HIV research would be directed towards CFS, so much useful studies could be done.

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