Monday, November 10, 2008

Giving Women Control Against HIV

HIV, the AIDS virus, "targets women with Darwinian ferocity," says Patrick Kiser, an assistant biomedical engineering professor at the University of Utah who got his Ph.D. at Duke. In Africa, the HIV infection rate among young women can be three times higher than men.

That's in part because females are at the "receiving end" of HIV-infected semen and partly because of their vulnerable societal status, Kiser said Nov. 6 at a Duke conference on Bioengineering Applications to Address Global Health. So while male use of condoms can prevent transmission, that requires far-from-certain negotiating between sexual partners.

Kiser's lab is working on techniques that would shift control to women by introducing agents called "microbiocides" to stop the virus cold in the vagina. But early experiments by others have not been promising, he said.

While one candidate gel preparation seemed to block the virus in laboratory culture, for example, the salt content of semen interfered with the agent's effectiveness. Also, women did not always follow instructions that called for applications before each sex act.

His group's tactic is to combine advanced microbiocides more attuned to bodily chemistries with better drug delivery techniques. As one example, it is developing flexible plastic intravaginal rings that can be made for pennies and deliver a constant amount of microbiocide for 30 days.

One gel method of action he described would trigger the release of anti-HIV drug when normally acidic vaginal fluids undergo a pH change upon intercourse (sperm is basic rather than acidic). At the same time, the normally free-flowing gel would chemically crosslink into a semi-solid to stop viral particles from reaching vulnerable white blood cells of the immune system.

Kiser is also collaborating with a Duke group headed by biomedical engineering professor David Katz.

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