HIV, the pandemic virus that causes AIDS, kills 2 million people each year worldwide. Malaria, a pervasive parasite spread by mosquitoes, infects 225 million people and kills 781,000 annually. The former disease has ravaged our species since spreading to us from monkeys a mere 40 years ago; the latter has been our enemy for so long, our bodies have evolved ways to fight it.
The two killers, new and old, actually have a few molecular similarities. Because of this — and some brand-new research — a single "superdrug" could soon fight both.
That drug is HIV protease inhibitor, a medicine that scientists designed specifically to treat HIV by preventing the deadly virus from constructing its proteins correctly. "HIV protease inhibitors are in clinical use now and are a leading HIV drug," said Photini Sinnis, head of the Medical Parasitology Laboratory at the NYU Langone Medical Center. "They have completely changed the face of HIV treatment in recent years. People who take these drugs don't die of AIDS anymore."
Proteases are enzymes that cut proteins into their correct shapes, allowing them to become active. HIV protease inhibitors stop the HIV virus in its tracks by preventing one of its protease enzymes from doing that job. Without the work of the protease, HIV proteins remain uncut and inactive, and so the HIV units, called virions, cannot assemble them to make new virions. The body has natural mechanisms for killing HIV virions, but it can only kill so many at a time; preventing the virus from replicating keeps the HIV cell population to a level that the body can handle.
Two birds, one stone
Over the past few years, several research groups (including Sinnis' group) have noticed a surprising positive side-effect of the HIV-specific protease inhibitors. "We're finding that the drugs have anti-malaria properties," Sinnis told Life's Little Mysteries, a sister site to LiveScience.
Researchers believe that HIV protease inhibitors shut down a protease present in the malaria parasite just like they do to protease in HIV. Sinnis' group has found that the anti-HIV drugs prevent the parasite from replicating in mice.
No human trials have been conducted, but the initial results in mice already have HIV researchers advocating the exclusive use of protease inhibitors for HIV treatment in Africa. "In Africa, where HIV and malaria overlap a lot, the HIV drugs we use should be the protease inhibitors," Sinnis said. "Then they would have the added benefit of inhibiting malaria infection."
