Neurobiological mediators of neuronal apoptosis in experimental neuroAIDS

Neuronal loss has often been described at post-mortem in the brain neocortex of patients suffering from AIDS. Neuroinvasive strains of HIV infect macrophages, microglial cells and multinucleated giant cells but not neurones. Processing of the virus by cells of the myelomonocytic lineage yields viral products that, in conjunction with potentially neurotoxic molecules generated by the host, might initiate a complex network of events which leads neurones to death. In particular, the HIV-1 coat glycoprotein gp120 has been proposed as a likely aetiologic agent of the described neuronal loss because it causes death of neurones in culture. More recently, it has been shown that brain neocortical cell death is caused in rat by intracerebroventricular injection of a recombinant gp120 coat protein and this occurs via apoptosis. The latter observation broadens our knowledge in the pathophysiology of the reported neuronal cell loss and opens a new lane of experimental research for the development of novel therapeutic strategies to limit damage to the brain of patients suffering from HIV associated dementia.