HIV and the BBB.

HIV can cause damage to the brain, including problems in thinking and understanding information. This damage is thought to occur because certain HIV drugs cannot get into the brain to suppress the HIV infection. The blood-brain barrier (BBB)is a tightly connected network of cells that surrounds

the brain and protects it from outside substances. However, the BBB also prevents many beneficial drugs from entering the brain. At the conference, 2 studies questioned whether using HIV medications that are able to get through the BBB actually protect against damage caused by HIV. In the first study (abstract 501), the cognitive ability of 32 HIV+ patients taking one of the medications believed to penetrate the BBB was compared to that of 14 HIV+ patients not taking one of these drugs. A second study (abstract 508) examined 165 HIV+ patients and compared cognitive ability in those patients taking an HIV medication thought to penetrate the BBB to those patients who were not. Both studies found that a higher viral load was associated with cognitive problems, rather than the specific HIV medications. In the second study, higher levels of education were shown to protect patients against these types of problems. In terms of protecting the brain and the body from HIV, the most important factor is keeping viral load low. Patients should be sure to have their viral load measured every 3 to 4 months and take HIV medications regularly and on-time.