Scientists Uncover Cause of AIDS Related Dementia


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Scientists Uncover Cause of AIDS Related Dementia Report.

Posted: April 21, 2004 2:20 p.m. ET

(New York City)  Researchers have uncovered an HIV/AIDS mystery that
affects about a quarter of the people infected with the disease.

Scientists at Philadelphia's Thomas Jefferson University,
Philadelphia have discovered that the virus produces proteins that
cause brain cells to die.

For twenty years doctors have been trying to determine why so many
people develop AIDS Related Dementia, and why there are not warning
signs it is coming on. 

Unlike other brain infections such as meningitis and herpes, HIV
causes hardly any brain inflammation or white blood cell increase.

The Thomas Jefferson team has found that HIV causes neurons - or
nerve cells - to die, leading to wastage of the brain.

This is "extremely unusual" and different to other infectious
agents, according to Dr Roger Pomerantz, at Jefferson Medical

The theory has previously been that HIV infects brain cells called
macrophages and miroglia, which then produce cytokines and
chemokines, killing neurons.

Dr Pomerantz's team tested whether the virus itself caused the nerve
cells to die, or whether this was caused by substances produced by
infected cells.

They looked at brain cells and T-lymphocyte blood cells, taking the
virus out of some of them and leaving it in others. When applied to
the nerve cells, they found they were killed when the virus and its
proteins were present.

"When we looked at T-cells, the only thing that killed neurons was
the virus," Pomerantz said..

"Once the virus is removed, nothing from the T-cells would kill

After investigating the neurons themselves, they found two well-
defined pathways to cell death, which were activated by proteins
from the virus.

Dr Pomerantz said: "We feel that it is mainly the virus and viral
proteins causing the neuronal cell death, and may now know the
precise pathways involved."

This would allow the development of treatments which prevent the
virus damaging the neurons, he said.

Dr Pomerantz's research appears in the Proceedings of the National
Academy of Sciences.

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 This story has been published with the permission of the author and can be found online at