Other candidates include potentially neurotoxic factors released by HIV-infected macrophages and microglia. To learn how HIV causes nerve cell death and to test potential therapeutic agents, our laboratory recently developed a cell culture model for HIV infection of human brain cells. Using this model, we found that only certain strains of HIV could infect human brain cells. Apoptosis is a cell suicide program that is believed to have a healthy function until it is set off by a disease process such as stroke and Alzheimer's disease, in which it has been implicated. Apoptosis is also a cause of immune cell death in AIDS, raising the possibility that HIV-related damage to the immune system and nervous system may share common mechanisms.
Apoptosis is activated by certain cell proteins and genes, some of which have been identified.
Recent studies have identified drugs that can block specific steps in the cell suicide program, providing hope that inhibiting nerve cell apoptosis may be a potential therapeutic approach for AIDS dementia and possibly other neurodegenerative disorders. The human brain cell culture model developed in our laboratory may therefore be a useful tool for discovering drugs that can prevent HIV-induced nerve cell suicide. We also examined brain tissue from AIDS patients and confirmed that nerve cell apoptosis occurs in the brains of patients with AIDS dementia, a finding recently reported by several other groups. We found evidence of nerve cell apoptosis in some AIDS patients without neurological symptoms, suggesting that the neurodegenerative process may start prior to the development of overt cognitive impairment. To develop a therapy for AIDS dementia, researchers hope t interfere and block effects of these neurotoxins.