U of M discovery offers potential breakthrough in preventing HIV transmissionby Lorna Benson, Minnesota Public Radio
Promising new research in monkeys has scientists excited about the prospects of preventing HIV transmission in humans. University of Minnesota researchers say they have discovered a way to block a cousin of the deadly virus in female Rhesus Macaques. They used an inexpensive food additive to do it.
St. Paul, Minn. — Public health officials have not had much success in preventing the spread of HIV around the world, but research at the U of M could change that. There are between two and three million new cases of HIV reported each year. Most of the infections are in sub-Saharan Africa where women represent close to 60 percent of the cases.
The product tested by U researchers is called Glycerol Monolaurate or GML. It's already approved by the FDA for human use. It's used primarily to extend the shelf life of certain foods.
"It's used in foods like ice cream and gravy. It's in cosmetics as an emulsifying agent and as a mild antimicrobial agent. It's also in breast milk so it is a naturally occurring compound," said Pat Schlievert, who has been studying GML in his U of M research lab since 1992.
The compound has a couple of very useful properties, he says. For one, it can prevent microorganisms from growing. Schlievert has used GML to stop the spread of dangerous toxins associated with Toxic Shock Syndrome. It also can kill Staph Aureus, Chlamydia and Candida.
GML's effectiveness has nothing to do with killing HIV. But it has another property that appears to stop the virus's transmission from males to females in primates.
"It actually stabilizes cells," Schlievert said.
That's important because HIV uses the body's own immune system against itself. When the body sends its T-cells to fight the HIV infection, the virus latches on to the cells and gets a free ride throughout the rest of the body.
Schlievert's team figured that GML's stabilizing properties could shut down the cells that essentially call in the immune system's T-cells. That prevents the virus from spreading.
"Basically it freezes them at that point for eight to 12 hours. It doesn't kill them, it freezes them. But then it allows them to take off again after that. So in that period when it's frozen it can't produce inflammation. You don't get the inflammation. That inflammation is necessary to attract the T-cells that become infected by the virus," he said.
Here's how it worked in the U of M monkey study, which is the closest example researchers have to an HIV infection in humans. Researchers inserted GML mixed with KY Warming gel into the vagina's of five Rhesus Macaques. They then exposed the monkeys to massive amounts of HIV. Two weeks later, they tested the animals to see if they had contracted HIV.
"Ordinarily when we expose these animals to these high doses two weeks later an infected animal will have hundreds of millions of copies of virus floating around in its bloodstream. And all of the GML treated animals had nothing at two weeks," Schlievert said.
Dr. Ashley Haase also worked on the study. His team repeated the process and again, none of the five monkeys became infected. However most of the monkeys in their control group, 4 out 5 animals, did contract HIV. But none of those animals had received GML.
The findings are "extraordinary," Haase said. But he also urges caution in reading too much in to the results.
For one, the study is very small. Also, a few months after the project ended, one of the five HIV free monkeys developed the infection. Researchers don't understand yet how that might have happened. But it poses an obvious concern for using the technique in humans if it's still possible to contract HIV months after exposure.
GML doesn't have to be perfect to be useful in the worldwide battle to stop the spread of HIV, Haase said.
"Something that was used 20 percent of the time at 60 percent efficacy could avert two and a half million cases in the next three years or something like that. So yes, we'd love 100% but we're perfectly happy with something that shows a high level of efficacy," Haase said.
That goal seems reasonable to Sharon Hillier. Hillier is the principle investigator for the Microbicide Trials Network, an HIV/AIDS clinical trials network established in 2006.
Hillier describes the U of M study as a "very exciting discovery" in part because it represents a new way of thinking about how to stop the virus. GML is also a product that currently costs just less than a penny per dose.
"The thing that's intoxicating about the idea is that something that's very inexpensive that could be used very widely and not have significant toxicity would be a tremendous benefit to women and men around the world in slowing down the epidemic of HIV," Hillier said.
The University of Minnesota has filed for a patent on GML's anti-inflammatory activities. But U researchers say the school probably would figure out a way to keep the cost low for uses related to preventing HIV. GML has a lot of other potential uses that could make money for the University such as preventing Gonorrhea and Chlamydia.
The U of M team is not really looking at their discovery as the sole approach to preventing the spread of HIV. There are some products currently available that they think might be even more effective when used in combination with GML.
Discovering those combinations will take time. Lorraine Teel is Executive Director of the Minnesota AIDS Project.
"Clearly we're at the beginning. We haven't gone through human trials with this yet. So there's a long way to go from the research lab to the pharmacy shelf and frankly to a woman's bedroom. So there's a long ways yet to go. But it's very good news," Teel said.
More animal studies are needed before human testing can begin on GML and HIV, researchers say.
One area the U of M wants to explore is whether the findings could apply to HIV infections acquired rectally. They haven't studied that possibility, but they don't think there's any reason why GML couldn't have an impact on transmissions between men.
The U of M findings are published in the latest edition of the journal "Nature."
The research was financed by National Institute of Health grants, funds from the National Cancer Institute and a grant from the National Center for Research Resources, a component of the NIH, to the Wisconsin National Primate Research Center.