A drug used to treat HIV can help restore memory loss in mice. The results are promising for humans.

ROBERT F. BUKATY/AP

An HIV drug may have another use.

In this week's issue of the journal Nature, a team reports that the medication appears to restore a type of memory that allows us to link an event, like a wedding, with the people we saw there.

The ability of Maraviroc to improve this sort of memory was demonstrated in mice, but the drug acts on a brain system that is also found in humans and plays a role in a range of problems with the brain and nervous system.

You might have an effect in Alzheimer's disease, in stroke, in Parkinson's and also in spinal cord injuries, according to Dr. S. Thomas Carmichael, chair of neurology at the University of California, Los Angeles.

From mice to maraviroc

The ability to link memories that occur at the same time is known as relational memory. It may be severely impaired in people with Alzheimer's disease.

Alcino Silva is the director of the Integrative Center for Learning and Memory at UCLA and is an author of the new study.

You learn about something, but you can't remember where you heard it. Silva says you cannot remember who told you about it.

Silva says that scientists have known about the existence of memory for a long time.

Silva's lab began studying a molecule called CCR5.

The immune system is made up of CCR5 in the body. The brain controls a process that separates recent memories from older ones. Without that separation, we would not know if we met someone at the wedding we attended last week or at a conference that happened decades ago.

Silva didn't believe that the CCR5 molecule could explain why people and mice have memory problems.

He says that they checked and voila.

The ability to link memories appears to be turned off by the increase in levels of CCR5 with age.

The idea was tested in mice with a disabled form of CCR5.

These mice were able to link memories made a week apart, while typical mice were only able to link memories made within a few hours of each other.

The team took typical middle-aged mice and infused maraviroc into the hippocampus, an area of the brain that is important to memory.

Silva says that the drug gave you the same thing.

A possible treatment for stroke

The results hold promise for older people and stroke patients.

Silva and Carmichael were among the authors of a paper showing that levels of CCR5 rise after a stroke.

The systems that help brain cells survive are the ones that stay active.

The process of forming new links between brain cells is similar to the one used to connect certain memories. That is prevented by CCR5.

They tried to give maraviroc to mice that had suffered a stroke or brain injury. They recovered faster than other mice.

They studied a group of stroke patients who had low levels of CCR5. Again, that meant faster recovery.

A study is being done to see if maraviroc can help people who have had a stroke.