VIH en el cerebro
HIV and the brain
Gail Shor-Posner, Ph.D., Universidad de Miami, EE.UU.
Cognitive impairment is the major neurological complication of HIV-1 infection, ranging in severity from a mild subclinical cognitive deficit to a dementing illness (HIV-1 associated dementia). The advent of protease inhibitors raises the possibility of HIV-1 suppression and potential eradication, as well as potential neuropsychological benefit. Despite these advances, no cure exists and even with the availability of effective antiretroviral therapies, HIV remains a serious psychological burden. Further, viral persistence may occur in the CNS and, with longer survival time, it is reasonable to predict that the destructive effects of HIV-1 within the brain will involve significant cognitive impairment.
Although the precise cause of HIV-1 associated dementia remains unknown, several factors affecting neuronal degeneration have been implicated, including impaired neuroprotection due to increased oxidative stress. The brain, which is particularly susceptible to oxidative stress, is protected from radical-mediated oxidative damage by a number of antioxidant defense systems. Inhibitors of oxidative damage and/or cytokines could, thus, be promising therapeutic agents for preventing progressive nerve cell death and slowing the advance of dementia.
Antioxidant therapies, for example, have been reported to improve cognitive function in late life in those without dementia, and decrease oxidative stress in HIV-1 infected patients. The results of our selenium-neuroprotection clinical trial suggest that supplementation with selenium, an in vivo antioxidant, may be a beneficial treatment to decrease psychological burden in HIV+ individuals. Moreover, an increase in enzymatic antioxidant defense systems, following supplementation with selenium, has been demonstrated in latently infected T lymphocytes, and in HIV/AIDS patients. Together, these findings indicate the potential importance of antioxidant administration in preserving, restoring, or enhancing systemic and brain immune responses that may prevent or slow the development of HIV associated cognitive disorders.