KHN Morning Briefing

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HIV Activates Biochemical Pathway That Leads to Nerve Cell Destruction in Brain, Study Says

HIV can activate a previously unknown biochemical pathway that leads to nerve cell destruction in the brain, a likely cause of neurological symptoms -- including dementia, seizures, depression and loss of memory and motor skills -- that some HIV-positive people experience late in the disease's progression, according to a study published in this month's issue of the journal Nature Neuroscience, the Wall Street Journal reports. Dr. Christopher Power, a physician and University of Calgary professor of neurology, and colleagues from the University of Calgary and the University of British Columbia have shown that white blood cells infected with HIV secrete an enzyme, known as MMP-2, that can convert the brain protein SDF-1 -- which normally helps to keep the brain healthy -- into a "brain-eroding poison." One of SDF-1's normal functions is to protect the brain from viruses such as HIV, which explains why dementia and other neurological problems occur late in the disease's progression, according to Power. "MMP-2 is normally relatively quiescent, but HIV turns it on," Power said, adding, "Other viruses don't turn it on." Avindra Nath, professor of neurology at Johns Hopkins University School of Medicine, said that the researchers' discovery "opens up a brand new area of research" that could lead to treatments for other neurological diseases such as Alzheimer's and multiple sclerosis, according to the Journal. Nath added that researchers have "only recently" begun to examine chemokines, a group of substances, including SDF-1, that play a role in brain function. Power said that it will be years before the research yields new treatments for AIDS-related dementia. However, he added that the cancer drug Prinomastat -- which drug maker Pfizer abandoned after the drug failed to show benefit in a Phase III trial in cancer patients -- has been "very effective" at blocking MMP-2 in mice (Carlisle, Wall Street Journal, 10/14).

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