The discovery refutes earlier medical studies that suggested HIV infection of astrocyte brain cells was considered rare and that the cells played only a minor role in the development of this disease
The findings were recently published in the prestigious scientific journal, Annals of Neurology.
The discovery was the result of collaborative research by Monash University Dean of Medicine, Nursing and Health Sciences, Professor Steve Wesselingh, St Vincent’s Hospital in Sydney and John Hopkins University in Baltimore, USA and led by the Burnet Institute’s Dr Melissa Churchill.
Professor Wesselingh said the discovery was extremely important to HIV research and the HIV community.
“It gives greater insight into HIV-associated dementia, and although it has a more rapid onset then age-related dementia or Alzheimer’s and is caused by a virus, this research is also highly significant in understanding Alzheimer’s,” Professor Wesselingh said.
HIV-associated dementia is caused by infection of the central nervous system and is a debilitating complication in people living with HIV or AIDS. It is the most common cause of dementia in people under the age of 40 and places considerable pressure on health resources in Australia and around the world.
HIV-associated dementia usually occurs at the later stages of HIV infection, when the immune system of patients is failing, but in some people it can occur within a few years of contracting the virus.
While there are drugs available to treat HIV infection, doctors have reported increased incidents of HIV-associated dementia. This is thought to be for two reasons; fewer patients are now dying from AIDS before the onset of HIV-associated dementia, and most existing drugs are inadequate for treating brain infection because they cannot effectively penetrate the brain.
Astrocytes are the most abundant cell type in the brain. They perform many important tasks critical for normal functioning of the brain. One major role is to maintain an optimal environment for neurons, which are the brain cells that instruct the body how to function.
It is possible that in HIV-associated dementia, astrocytes may stop functioning normally when they are infected with HIV, which may then result in neurons dying or not functioning normally. Unlike other cell types in the body that constantly regenerate, astrocytes are long-lived and do not readily regenerate. Therefore, the effect that HIV has on astrocytes may be long-term or even permanent.
There is currently a major focus in the field of HIV research to identify novel ways to permanently eradicate HIV from the body (effectively curing HIV infection), in particular from so-called “viral reservoirs” that are hard to treat with anti-HIV drugs.
The results of this new study highlight the brain as an important viral reservoir. Therefore, the new strategies that are being designed to eradicate HIV from the body must also be designed to eradicate virus from brain astrocytes.
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