With results that admittedly surprised investigators, a team of researchers at Georgetown University Medical Center (GUMC) announced that lab tests have shown that morphine, a strong pain-killer that can be used to make heroin, protects against HIV brain toxicity in rats.

“We started with the opposite hypothesis – that heroin was going to destroy neurons in the brain and lead to HIV dementia,” admitted Italo Mocchetti, a professor of neuroscience at GUMC, in a press release.

Instead, they found that morphine had a protective effect on the brain.

HIV-associated dementia is caused by brain damage that can occur when infected white blood cells bring HIV into the brain.

Sufferers can experience a range of symptoms with varying degrees of severity, including behavior changes, reduced range of motion, or memory loss.

Before the highly active antiretroviral (HAART) era, HIV dementia was common in patients, and as many as 50 percent of AIDS patients experienced some signs of dementia before succumbing to AIDS.

Although seen less frequently today, HIV-associated dementia still appears in some individuals and is especially likely to be seen in areas of the world where HAART remains unavailable.

Recent studies have also shown that cases of HIV dementia have gone up slightly, possibly due to development of HIV drug resistance.

The GUMC team began their investigation because of the high numbers of HIV-positive individuals who also use heroin. Heroin can increase the risk of developing neurological problems, although some users never seem to have any.

Contrary to the researchers’ expectations, in the rats studied, morphine prevented toxicity resulting from HIV. In particular, the investigators found that morphine spurs the production of protein CCL5, which is released by a certain kind of brain cell.

This protein activates factors that inhibit HIV infection of immune cells, making HIV less toxic in the brain.

The results are still very preliminary, and the action of morphine needs further investigation. Additionally, the scientists found that morphine only acted on a particular strain of HIV, the M-tropic strain.

This is the same strain that the anti-HIV drug Selzentry (maraviroc) works on, and is typically found in earlier stages of infection.

Nonetheless, the researchers find their result promising.

“We believe that morphine may be neuroprotective in a subset of people infected with HIV,” said Prof. Mocchetti. “That is not to say that people should use heroin to protect themselves – that makes no medical sense at all – but our findings gives us ideas about designing drugs that could be of benefit.”

“Ideally we can use this information to develop a morphine-like compound that does not have the typical dependency and tolerance issues that morphine has,” he added.

Their findings were announced at the 16th Scientific Conference of the Society on NeuroImmune Pharmacology in Manhattan Beach, California.

For more information about HIV dementia, please see WebMD’s eMedicine website. To read more about the investigation, please see the press release at the Georgetown University Medical Center website.