A new test developed at the Institute of Psychiatry in London will provide much better evidence on which anti-HIV drugs control HIV replication in the brain, according to a presentation at Tuesday’s annual Conference of the Public Health Laboratory Service.
A laboratory study at London University's Institute of Psychiatry used samples of foetal brain tissue to test the protective effects of the nucleoside analogue d4T (stavudine, Zerit) on the main groups of brain cells, including neurons, astrocytes, oligodendrocytes, macrophages as well as neurotransmitters. The samples were divided into two groups, one of which was kept as a control and the other infected with HIV. When treated with d4T, the condition of all the HIV infected cells improved to resemble the uninfected cells in the control group.
They found that d4T not only has the ability to suppress the ability of HIV to replicate, but also appears to prevent HIV from causing damage to brain cells and to restore damage to these cells when it has occurred.
HIV enters the brain soon after infection causing cognitive disorders and in some cases HIV-related dementia. Although treatment with HAART has dramatically reduced the incidence of brain disorders in people with HIV, there has been some uncertainty as to which drugs offered the best neurological protection.
Dr Kandanearachi who presented the results said: "This is clearly very encouraging data."
The same research group has also shown that even when HIV activity in brain tissue is upregulated by exposing it to granulocyte macrophage colony stimulating factor (GM-CSF), d4T can still overcome higher levels of HIV replication. Prof. Ian Everall said that the group has also looked at AZT and abacavir, and plan to look at other drugs to assess which compounds have the best anti-HIV activity.
“The issue of anti-HIV activity in the brain continues to be important because in cases of drug resistance, we need to know which compounds will also be active in the brain when selecting new regimens”, he said.