Saturday, March 7, 2009

Inexpensive Compound May Offer Protection Against AIDS

AIDS has been described as “one of the most destructive microbial scourges in history,” and for good reason. In just over 25 years, the disease has claimed more than 25 million lives worldwide. The number of people living with HIV, the virus that causes AIDS, has risen from around 8 million in 1990 to 33 million today, and is still growing. There is no cure for AIDS, and currently the only way to remain safe is not to get infected. The surest way to do that is by abstaining from sex or monogamy with an uninfected partner. Condoms are not 100 percent safe, but if used properly, will reduce the risk of HIV transmission. However, experts say women often acquire HIV in situations where it is difficult or impossible for them to refuse sex or negotiate condom use. They need a safe and discrete way to protect themselves—and scientists say they may have found just the thing.

Researchers at the University of Minnesota tested a common compound called glycerol monolaurate, or GML, used in ice cream, cosmetics and found in breast milk in macaque monkeys. After mixing the compound with Johnson and Johnson’s K-Y Warming Liquid, they placed the treatment into the vaginas of five monkeys and then applied SIV, a monkey version of HIV. Four out of five avoided infection while five monkeys that got the gel without GML were all infected after exposure to SIV. GML appears to work by stopping the immune-system cells, or T-cells, which are usually targeted by the virus, from moving to the infected regions of the vagina, thus reducing the opportunity for HIV to take hold. “Even though it sounds counter-intuitive, halting the body’s natural defense system might actually prevent transmission and rapid spread of the infection,” said chief investigator, Dr. Ashley Haase, head of the Department of Microbiology at the University.

While the treatment does not provide 100 percent protection, it could still greatly reduce a woman’s risk of being infected. “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 percent but we’re perfectly happy with something that shows a high level of efficacy,” Haase said. The researchers have been asked if their findings could apply to HIV infections acquired rectally, and though they haven’t studied that possibility, they see no reason why GML couldn’t have an impact on transmissions between men.

GML’s use as a microbicide and anti-inflammatory was discovered by one of the researchers, Patrick Schlievert, when he explored toxic shock syndrome in the use of menstrual tampons. He found that the compound inhibited the toxin-making mechanism of the germ Staphylococcus aureus. Tampons coated with GML protected women from the bacterium and eased vaginal inflammation. Schlievert says GML has already been repeated tested and proven safe, and as an added bonus, is inexpensive, costing less than a cent for each dose for a woman, and is easy to formulate in many ways for vaginal use. “This result represents a highly encouraging new lead in the search for an effective microbicide to prevent HIV transmission that meets the criteria of safety, affordability and efficacy,” the authors wrote.

Dr. Jeffrey C. Laurence, a professor at Cornell University who studies AIDS and a senior scientist for programs at The Foundation for AIDS Research, called the new study “innovative” because the treatment targets the body’s immune responses rather than directly killing the virus itself. He says the challenge is to develop a product that prevents AIDS and is also “unobtrusive, easy to use, and has long-lasting effects so that it need not be applied daily or before each act of intercourse.”

The University of Minnesota has filed for a patent on GML’s anti-inflammatory activities. Schiefert said the school would probably figure out a way to keep the cost low for uses related to preventing HIV. He says GML has a lot of other potential uses that could make money in the U.S. such as preventing gonorrhea and chlamydia.

Last month, scientists reported the first positive trial of a microbicide, a gel made by Massachusetts-based Indevus Pharmaceuticals called PRO 2000, but it reduced the risk of infection by only about 30 percent. Another microbicide, BufferGel made by ReProtect Inc., was also tested, but showed no significant effect on HIV transmission. Other research presented the same day at a meeting in Montreal suggested that Gilead Science’s Inc.’s Viread and Truvada in gel or oral form might also prevent the spread of HIV.

Today, 33 million people are living with HIV, and that number is still growing. Most of the infections are in sub Saharan Africa where women represent close to 60 percent of the cases. As Haase said: “The pandemic continues to grow unless we find a way to stop transmission.”