Five monkeys infected with simian immunodeficiency virus (SIV), a very close relative of HIV, and treated with minocycline had less damage to brain cells, less brain inflammation, and less virus in the central nervous system than six infected monkeys that received no treatment, the researchers report in the April 27 issue of the Journal of the American Medical Association.
"In people, antiretroviral treatments do a great job of controlling HIV in blood, but most of the drugs don't cross the blood-brain barrier very well," says Christine Zink, D.V.M., Ph.D., professor of comparative medicine at the Johns Hopkins University School of Medicine. "As a result, even though the infection seems to be controlled, it may still cause damage in the brain. And because people are living with HIV longer than ever, the prevalence of neurological damage is increasing. Currently, there's no drug to treat it directly."
In use for more than 30 years, minocycline was specifically designed to cross the blood-brain barrier, the biological "wall" that limits what can pass from the blood into the brain. Other researchers have reported that this antibiotic can protect brain cells in animal models of other diseases -- multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, stroke and more. The drug is being tested in early clinical trials for some non-HIV-related conditions.
"Last year we discovered that SIV triggers some of the same biological pathways of cell death and inflammation as these other diseases," says Sheila Barber, Ph.D., assistant professor of comparative medicine. "Testing minocycline in our animal model of HIV infection was really a logical next step."